Abstract
ABSTRACTS (BY NUMBER)
These are the abstracts as submitted through the website. Last minute changes, title and presenting changes are not always reflected in this file.
“It’s Not Free to Pee.” – Development of NOVO-120 for the Treatment of Bladder and Sensory-Motor Dysfunction After Spinal Cord Injury in Male and Female Rats
1Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, United States, 2Novoron Bioscience, San Diego, United States, 3Department of Physiology, University of Kentucky, College of Medicine, Lexington, USA, 4Department of Pharmacology and Toxicology, Michigan State University, College of Osteopathic Medicine, East Lansing, USA
Spinal cord injury (SCI) often causes irreversible motor, sensory, and autonomic dysfunction. In addition to paralysis, ∼80% of individuals with SCI experience persistent bladder and bowel issues and treatment options are limited. NOVO-120 is a proprietary humanized derivative of LRP1 Receptor Associated Protein, developed by Novoron Bioscience, designed to overcome axon growth inhibition caused by myelin-associated inhibitors that are present after spinal cord injury. Importantly, NOVO-120 administration bypasses the blood-brain barrier, reducing off-target effects and maximizing bioavailability at the spinal cord injury, through intrathecal (IT) delivery - an established clinical route - and it is compatible with IT infusion formulation. In preliminary studies with IT infusion of NOVO-120 in a female rat model of moderate thoracic contusion (T9), we found significantly accelerated recovery of bladder function and improved locomotor outcomes. NOVO-120-treated animals demonstrated earlier volitional voiding, reduced bladder weight and wall thickness, and enhanced BBB locomotor scores relative to controls. The work to be presented includes both male and female rats, larger sample size, and expanded outcome measures to also include urodynamic testing, Catwalk and Gridwalk gait analysis, histological assessments of spinal tissue and bladder remodeling, and biomarker profiling from urine and serum. The study design incorporates clinically relevant parameters for translation, including an 8-hour post-injury treatment delay to reflect real-world clinical feasibility where treatment would coincide with decompression surgery. Although studies are ongoing, the development of a clinically viable therapy that improves locomotor and bladder outcomes after SCI is of significant translational impact.
Funding: Christopher & Dana Reeve Foundation.
A Chemically Gated Platform for Precise Control of Viral Gene Expression in the Central Nervous System
1Department of Biomedical Sciences, Marquette University, Milwaukee, United States, 2Department of Chemistry & Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, United States, 3Milwaukee Institute for Drug Discovery, University of Wisconsin-Milwaukee, Milwaukee, United States
Background: Gene therapy approaches offer solutions to nervous system disorders with unprecedented molecular and cellular precision but are currently hampered by their irreversibility and lack of dose control. Inducible expression systems, in which transgenes are regulated by delivery of exogenous compounds, offer an elegant solution. Currently available inducible systems, however, can have non-zero baseline expression (“leak”) and/or unfavorable kinetics. We therefore aimed to design a novel, dual-compound system for non-leaky and rapidly reversible control of viral transgene expression.
Methods: A split transcription factor was engineered in which transcriptional activity is triggered when an agrochemical causes association of DNA-binding and transcriptional activation domains. In addition, expressed proteins were engineered to include destabilizing dihydrofolate reductase (DHFR) domains, allowing controlled protein stabilization by an antibiotic called trimethoprim. Inducible gene control was tested in a 293T cell culture reporter assay, and reporter activity was tested by viral expression in adult mice.
Results: In 293T culture assays, reporter expression was undetectable in the absence of activating compounds and was strongly expressed when compounds were supplied (EC50 = 302 nM). In vivo, delivery of reporter alone produced signal in fewer than 0.5% of transduced CST neurons, while co-expression of a fused version of the activating transcription factor drove signal in 94.0% ± 2.08 of CST neurons (p < 0.01, unpaired t test), confirming reporter fidelity.
Conclusion: Cell culture testing confirms tight regulation of transgene expression with a novel dual-compound system, and ongoing structural modifications seek to optimize compounds for in vivo use.
A Clinical Neural Stem Cell Line Extensively Restores Skilled Forelimb Function After Primate Cervical Spinal Cord Injury
1Dept. of Neurosciences, University of California - San Diego, La Jolla, CA, 2Veterans Administration Medical Center, La Jolla, CA, 3Dept. of Neurosurgery, University of California, San Francisco, CA, 4California National Primate Research Center, University of California, Davis, CA, 5Departments of Neurology and Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA, 6Veterans Administration Medical Center, Bronx, NY, USA, 7College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, 8Mechatronic Systems Engineering, Simon Fraser University, Surrey, British Columbia, Canada, 9International Collaboration on Repair Discoveries (ICORD), Vancouver, British Columbia, Canada, 10Veterans Administration Medical Center, San Francisco, CA
We previously demonstrated that human neural stem cells (hNSCs) or multipotent neural progenitor cells (hNPCs) grafted into sites of rodent or rhesus monkey spinal cord injury (SCI) survive, extend axons, form synapses, support host axon regeneration, and improve functional recovery. To advance clinical translation, we developed a new GMP-compatible spinal cord neural stem cell line, H9-scNSCs, derived from human embryonic stem cells and directed toward a spinal cord identity. We grafted H9-scNSCs into rhesus monkeys using two SCI models: C7 hemisections and C6 hemi-contusions, with grafting performed two weeks after hemisection and 3–4 weeks after contusion. H9-scNSC grafts placed into either injury model supported up to 50% recovery of skilled forelimb function. Anatomically, grafts promoted regeneration of host corticospinal, raphespinal, and heavy-chain neurofilament–expressing axons into the lesion by four months post-injury. In turn, graft-derived neurons extended extensive axonal projections into the distal host spinal cord, with mean axon counts of 66,200 ± 25,100 in the hemisection model and 87,636 ± 30,136 in the contusion model, reaching distances up to 40 mm. Graft composition included 18 ± 6% NeuN+ neurons, 51 ± 6% Sox9+ astrocytes, and 9 ± 2% Olig2+ oligodendrocytes, approximating normal human spinal cord gray matter ratios. Among NeuN+ neurons, 71 ± 3% expressed CamKII and 15 ± 4% expressed GABA, indicating predominantly excitatory neuronal differentiation. H9-scNSCs are now produced under full GMP conditions and will advance toward clinical translation pending completion of ongoing GLP safety and efficacy studies.
A Diffusion MRI-Derived Brain Health Summary for Detecting White Matter Abnormalities After TBI
1Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States, 2Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States, 3Department of Neurosurgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States, 4Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States
Objective: To develop a diffusion MRI-based white matter (WM) brain health summary for TBI and determine whether patterns of WM abnormalities associate with long-term functional outcome.
Methods: Longitudinal harmonization of TRACK TBI scans with IXI and UK-Biobank yielded a reference dataset (n=13123; 428 TBI, 12695 controls). Free-water volume fraction (FW-VF) was averaged within major WM systems (association, projection, corpus callosum, lobar WM), generating bilateral average and asymmetry features. Non-parametric, sex-specific reference intervals (RIs) were constructed using ≥120 controls per age bin (single RI for ages 18–48; 1 year bins for 48–76). The brain health summary for each patient comprised feature-level outlier indicators (average: low/high; asymmetry: any deviation). We systematically evaluated single and pairwise outlier patterns using logistic regression for associations with 12-month outcomes: GOSE≤6 and impaired performance (≤10th percentile of controls) on RAVLT, TMTA, and TMTB.
Results: Among 225 TBI participants without lesions, the brain health summary revealed multiple WM abnormality patterns associated with outcomes (p<0.05, corrected). Elevated FW-VF in frontal WM was associated with poor RAVLT performance (RAVLT≤37, OR=7.5(95% CI:1.16-48.1)). Elevations in corpus callosum (OR= 6.9(95% CI:1.5-32.0)) and association WM (OR=4.7(95% CI:1.1-20.3)) were associated with impaired TMTB performance (time≥107s). Higher projection WM FW-VF was associated with GOSE≤6 (OR=3.69(95% CI:1.29-10.55), p=0.015, uncorrected). No significant associations were observed for asymmetry or TMTA-time.
Conclusion: Early WM free water abnormalities in TBI patients identified clinically relevant patterns associated with poor cognitive performance at 12 months. These results support the feasibility of a diffusion-based brain health summary for prognostic enrichment in TBI research and clinical trial design.
A Gyrencephalic Model of Controlled Cortical Impact Recapitulates Common Focal and Diffuse Pathologies of Moderate and Severe TBI
1Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States, 2Corporal Michael J. Crescenz VA Medical Center, Philadelphia, United States, 3Department of Neuropathology, Queen Elizabeth University Hospital, Glasgow, United Kingdom, 4Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, United Kingdom, 5Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
The cause of over 300,000 hospitalizations per year, moderate or severe traumatic brain injury (TBI) comprises variable focal and diffuse pathologies that are critical for determining outcome. Reproducible and clinically relevant preclinical models of TBI are essential tools for both exploring mechanisms of disease and effectively translating diagnostic and therapeutic interventions for clinical application. Modeling TBI in the swine brain may confer notable advantages for achieving clinically relevant pathological outcomes by allowing for relevant biomechanical forces, a gyrencephalic structure, and appropriate white matter volumes. Here, we adapted the well-established controlled cortical impact (CCI) model for use in swine (sham = 2, CCI-injured = 5) to examine the immediate mechanically induced and early evolution of focal and diffuse pathologies. We demonstrate that cortical impact, absent any head rotational acceleration, induces focal hemorrhagic contusion, with associated cell death, and extensive glial reactivity in the impacted region. Importantly, while extensive axonal pathology was observed underlying the impact site, a more limited degree of diffuse, mechanically induced axonal pathology was observed remote from the focal lesion in a stereotyped distribution. In addition, significant elevations in serum neurofilament-light were observed at 3 days post-CCI injury. Parallel post-mortem examinations of the neuropathology following acute human TBI validate the clinical relevance of findings. As such, this model recapitulates multiple common focal and diffuse pathologies of acute human moderate or severe TBI and demonstrates utility as a translational model.
A Human Organoid Model of Traumatic Brain Injury Reproduces Synergy Between Repeated Injuries
Ms. Shahrzad Shiravi1, Dr. Hirushi Gunasekara1, Dr. Han Xu1, Dr. Ying S. Hu1,
1University of Illinois Chicago, Chicago, United States
Repeated traumatic brain injury (TBI) is common in populations such as athletes and military personnel. Clinical studies and pre-clinical rodent models indicate that TBI outcomes are worse in subjects with a history of TBI. However, this synergy has not previously been reproduced in a human pre-clinical model. The objective of this study was to develop a human organoid model of repeated TBI and determine whether repeated injuries produce synergistic pathology.
Human induced pluripotent stem cell–derived cortical organoids were subjected to controlled dynamic compression using a custom-built device. Organoids received either a sham procedure, a single injury, two injuries separated by 4-hour interval, or two injuries separated by a 1-week interval. Forty-eight hours after the final injury, organoids were stained for confocal microscopy with CalBryte 520 AM and tetramethylrhodamine methyl ester (TMRM) to quantify calcium dynamics and mitochondrial membrane potential, respectively. Lactate dehydrogenase (LDH) release was measured to evaluate cytotoxicity, and organoid cryosections were immunostained with TOM20 and imaged using super-resolution microscopy to examine mitochondrial morphology.
Injury phenotypes included reduced mitochondrial membrane potential, mitochondrial fragmentation, LDH release, reduced spontaneous electrophysiological activity, and reduced viability. Changes in mitochondrial membrane potential and cell death were amplified in the repeated injury group relative to the single injury group when the interval between injuries was 4 hours but not when the interval was 1 week, indicating a finite period of vulnerability after injury in this model.
These findings establish a human pre-clinical model for investigation of synergy between repeated TBIs.
A Nationwide Study Exploring Factors Associated with Unplanned Intubation Following Severe Isolated Traumatic Brain Injury in Adults
1Suny Downstate Health Sciences University, Brooklyn, United States, 2Icahn School of Medicine at Mount Sinai, New York, United States
Objective: Unplanned intubation following traumatic brain injury (TBI) reflects significant respiratory deterioration. This study analyzed factors linked to unplanned intubation among adults with severe isolated TBI using a national database.
Methods: Adults (≥18 years) with severe isolated TBI were identified in the National Trauma Data Bank from 2019–2021. Severe isolated TBI was defined as head Abbreviated Injury Scale (AIS) ≥3 with no additional body AIS ≥3. Unplanned intubation was recorded when a patient required reintubation more than 24 hours after extubation, or new intubation during hospitalization due to acute clinical decline. Multivariable logistic regression was used to identify factors associated with unplanned intubation, reported as adjusted odds ratios (aOR) with 95% confidence intervals (CI).
Results: Among 250,443 adults with severe isolated TBI, 6,049 (2.4%) experienced unplanned intubation. Indicators of greater neurological injury were associated with higher odds of this event, including Glasgow Coma Scale scores of 3–8 (aOR 2.28, 95% CI 2.08–2.50; p<0.001) and midline shift (aOR 1.40, 95% CI 1.31–1.51; p<0.001). Patients undergoing cerebral monitoring (aOR 1.84, 95% CI 1.67–2.03; p<0.001) and receiving venous thromboembolism prophylaxis (aOR 4.35, 95% CI 4.07–4.65; p<0.001) also displayed higher odds. Complications strongly associated with unplanned intubation included acute respiratory distress syndrome (aOR 8.93), acute kidney injury (aOR 9.43), and catheter-associated urinary tract infection (aOR 6.08) (all p<0.001).
Conclusion: Unplanned intubation was associated with markers of neurological injury and several inpatient complications among severe TBI patients. Identifying such factors may assist clinicians in anticipating respiratory failure and optimizing airway management in TBI care.
A New Classification for Acute, Blunt, Traumatic Clivus Fractures Based on the Mechanism of Injury
1Division of Trauma Surgery, Valleywise Health Medical Center, Phoenix, United States, 2Creighton University School of Medicine-Phoenix, Phoenix, United States, 3Department of Radiology, Valleywise Health Medical Center, Phoenix, United States, 4New York University, New York, United States, 5Valleywise Health Medical Center, Phoenix, United States, 6Department of Pediatrics, Valleywise Health Medical Center, Phoenix, United States, 7Division of Plastic Surgery, Valleywise Health Medical Center, Phoenix, United States, 8Division of Plastic Surgery, Mayo Clinic, Phoenix, United States, 9Division of Neurosurgery, Valleywise Health Medical Center, Phoenix, United States, 10University of Arizona, College of Medicine Phoenix, Phoenix, United States
Current classifications of clivus fractures are based on fracture anatomy. These classifications do not fully capture or characterize all clivus fractures.
A retrospective study was conducted between 2007-2024. Blunt injuries were classified by mechanisms into direct impact related Type A (medial impact), and Type B (lateral impact), or indirect impact related Type C (shear, flexion, distraction, impaction or torque). Type Mix characterized any combination of Types A-C. Medial direct impact was defined as any impact on the head excluding the temporal plane posterior to the Pterion. Lateral direct impact was defined as an impact over the temporal plane posterior to pterion, anterior to the mastoid and ventral to the insertion of the temporalis muscle.
80 patients were included. We identified 36 Type A injuries (45%), 25 Type B (31.25%), 13 type C (16.25%), and 6 Type Mix (7.5%). Overall mortality was 36.25%. Mortality was highest for Type Mix (50%) and lowest for Type C (23.08%) (p=0.006). Risk of cerebrospinal fluid leak was highest 66.67% for Type Mix, and lowest 15.38% for Type C (p=0.027). Cranial nerve injury was highest in Type Mix and lowest in Type C (p=0.011). Cervical spine injuries needing treatment (collar, halo, and/or surgery) were highest in Type Mix (100.0%) and Type C (92.31%), but lowest in Type A (25.0%) or Type B (16.0%) (p<0.001). No correlation amongst the injury types and vascular dissection (p=0.262) or endocrinopathy (0.215) was found.
This classification newly identified Type Mix clivus fractures with highest risk of morbidity and mortality.
A Novel Model of Post-Traumatic Epilepsy in a Neuroplasticity-Susceptible Rat Strain
1University of Wisconsin School of Medicine and Public Health, Madison, United States, 2William S Middleton Memorial Veterans Hospital, Madison, United States
Traumatic brain injury (TBI) is a common cause of human epilepsy, accounting for 10–20% of symptomatic epilepsy. Reproduction of this phenotype in rodents has been challenging. Our objective was to develop a novel model of post-traumatic epilepsy (PTE) using a rat strain with high susceptibility to PTE after a moderate-severe TBI.
Utilizing a strain of inbred rats selected for susceptibility to neuroplasticity in the kindling model, Perforant Path Kindling Susceptible (PPKS), rats (3–4 months old) underwent moderate-to-severe TBI induced by controlled cortical impact (CCI). Freely behaving rats underwent serial video-EEG monitoring continuing for 5–6 months. Spontaneous seizures were identified both by visual review and through a machine learning approach.
For a subset of animals, recordings averaged 138 hours per animal (range 118–166 hours). Spontaneous recurrent seizures were detected in 53.3% of rats (16/30), beginning at 57±4.4 days post-CCI. Electrographic seizures consisted of rhythmic spike/spike-wave discharges, at times >30 secs, and were associated with behavioral arrest and oral automatisms, accompanied by impaired responsiveness to external stimulation. In animals with PTE, seizures became longer (4.9±0.2 vs 11±1.4 sec, p<0.01) and more frequent (2.4±0.6 vs 12±2 per hr, p<0.01) over time. A deep convolutional neural network (DCNN) utilizing multiplexed images of EEG spectral content, kurtosis, and entropy identified seizures with high sensitivity.
These findings demonstrate a novel rodent model of PTE with an incidence of epilepsy, frequent seizures, and progression after the first seizure. This model provides a robust platform for studying epileptogenesis after TBI and perhaps in PTE.
A Novel Molecular Strategy for Strong, Cell-Autonomous Activation of Regenerative JAK/STAT Signaling in Corticospinal Tract Neurons
Dr Zimei Wang1, Dr. Syed Roshan1, Akhila Kasturi1,
1Department of Biomedical Sciences, Marquette University, Milwaukee, United States
Background: Elevation of JAK/STAT signaling, achieved by cytokine ligands and/or knockout of the feedback inhibitor SOCS3, stimulates axon regeneration in the optic and sensory systems. In the corticospinal tract (CST), however, similar strategies have yielded variable and generally smaller effect sizes. We therefore revisited the molecular efficacy of currently available tools and compared them with a novel method of JAK/STAT activation based on forced dimerization of cytokine receptors.
Methods: CST neurons of adult mice were retrogradely transduced with AAV constructs carrying constitutively active STAT3 (caSTAT3), Hyper-IL-6, or forced-dimer constructs in which the extracellular domains of GP130 and LIFR receptors were engineered for continual dimerization and ligand-independent cross-activation. Pathway activation was assessed by immunohistochemistry for STAT3 phosphorylation, and transcriptional effects were measured by single-nucleus RNA sequencing.
Results: caSTAT3 constructs produced minimal pSTAT3 signal in CST neurons, indicating low JAK/STAT activation. Hyper-IL-6 elevated pSTAT3 in CST neurons but also caused widespread microglial activation and a rapid decline in animal weight and well-being, requiring humane euthanasia. Forced-dimer constructs produced strong pSTAT3 signal that was specific to CST neuronal nuclei, indicating JAK/STAT activation. Consistent with this, snRNA-seq detected strong upregulation of hundreds of transcripts, including canonical JAK/STAT target transcripts (e.g. Ccl2, Timp3, Socs3), and enrichment for Gene Ontology terms related to cytokine signaling.
Conclusion: Compared to existing caSTAT3 and Hyper-IL-6 strategies, a novel molecular strategy based on forced dimerization of engineered cytokine receptors offers a stronger and more selective means of elevating JAK/STAT signaling in CNS neurons.
A Novel Multimodal Pharmacologic Strategy for Severe TBI: Case Series of Guanfacine, NAC, and Donepezil (GND) Therapy
Dr. Arman Fesharaki-zadeh1
1Yale University, New Haven, United States
Background: Traumatic brain injury (TBI) remains a major cause of long-term morbidity and disability worldwide. Individuals with moderate to severe TBI frequently exhibit persistent neurocognitive deficits—including short-term memory impairment, executive dysfunction, and slowed cognitive processing—for which there are currently no FDA-approved treatments.
Objective: To evaluate the combined use of guanfacine, N-acetylcysteine (NAC), and donepezil (GND) as an adjunct to cognitive rehabilitation in individuals with chronic moderate to severe TBI.
Methods: This case series examined patients treated with the GND regimen alongside ongoing cognitive rehabilitation. Treatment effects were assessed using pre- and post-intervention Montreal Cognitive Assessment (MoCA) scores. Prior studies suggest guanfacine/NAC may improve working memory and executive function in mild TBI, motivating investigation in more severe presentations.
Rationale for Agents:
Guanfacine: α2A-adrenergic agonist approved for ADHD; enhances prefrontal cortical function.
Donepezil: Cholinesterase inhibitor used to treat cognitive symptoms in mild cognitive impairment and early dementia.
N-acetylcysteine: Antioxidant and glutamate modulator with demonstrated neuroprotective effects in TBI and other neurological conditions.
All three agents have established safety profiles.
Results: Across cases, the GND regimen was associated with encouraging improvements in MoCA performance, suggesting synergistic cognitive benefit when combined with structured rehabilitation.
Conclusions: Preliminary findings indicate that the GND combination may represent a promising multimodal pharmacologic strategy to address chronic neurocognitive sequelae in moderate to severe TBI. Larger, placebo-controlled trials are warranted to further evaluate safety, efficacy, and translational potential.
A Protective Helmet-Like Interface Allows for Higher Energy Impacts in the CHIMERA Traumatic Brain Injury Model in Laboratory Rats
1Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, United States, 2Preclinical Behavior and Modeling Core, Department of Laboratory Animal Resources, Uniformed Services University, Bethesda, United States, 3Department of Anatomy, Physiology, and Genetics, Uniformed Services University, Bethesda, United States
The Closed-Head Impact Model of Engineered Rotational Acceleration (CHIMERA) has been developed to study impact-acceleration head injuries in laboratory animals. While well validated in mice, its use in rats remains challenging as energy levels necessary to produce an observable injury can lead to skull fractures and/or death. The aim of our research is to validate the use of a small helmet-like interface in the rat CHIMERA model, providing adequate protection against skull fractures while allowing for an increase of applied impact energy levels. We first determined the optimal energy level necessary to produce pathology without skull damage or mortality after a single CHIMERA impact with the interface, in male and female Sprague-Dawley rats, at levels ranging from 2.9 J to 8.4 J. Our results show that 6.0 J in males, and 7.4 J in females, is sufficient to induce an observable acute behavioral and neurobiological impairment, while preventing skull fracture and death. Additionally, using high-speed videography analysis, we found that the interface didn’t significantly change the head kinematics (trajectory or velocity) after impact. Finally, we further characterized the resulting injury at 6.0 J by assessing motor and cognitive function and brain pathology up to 35 days post-injury. While our results in males failed to show a behavioral impairment following a 1-time impact, our research is ongoing to characterize the injury in females and following repeated impacts. Overall, we found that the interface allowed for higher impact levels than previously published for rats, while effectively preventing skull fractures and death.
A Single Concussion in Juvenile Mice Leads to Sex-Specific Acute Cerebrovascular and Blood-Brain Border Dysfunction
1Department of Neuroscience, University of California, Riverside, Riverside, United States, 2Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, United States, 3Centre d’Études Biologiques de Chizé, CNRS-UMR7372, La Rochelle Université, Villiers-en-bois, France, 4Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, United States
Objectives: Traumatic brain injury (TBI) can induce alterations to the blood–brain border (BBB) that contributes to long-term deficits. We examined the temporal evolution of BBB and cerebrovascular alterations after concussion in juvenile mice.
Methods: Postnatal day 17 (PND17) C57BL/6J male and female mice were subjected to sham or single closed head injury with long-term disorders (CHILD). At 1h, 6h, 1d, 3d, and 7d post-injury (dpi), Evans blue (EB) was administered to evaluate BBB permeability, followed by vessel painting to visualize cerebral vasculature. Brain tissue properties, including edema, were assessed using MRI-based T2 relaxation mapping at 1dpi.
Results: Single early-life concussion induced hyper-acute structural and functional alterations in brain vasculature: 1) disruption of physiological functions and developmental trajectories, 2) reduced brain volumes and sex-dependent T2 relaxometry changes, and 3) hyper-acute increases in BBB permeability which correlated with cerebrovascular rarefaction. Notably, males exhibited more BBB and vascular perturbations than females, revealing sex-dependent vascular responses to CHILD. Smaller penetrating cortical vessels were more susceptible to alterations compared to larger pial blood vessels. Multivariate modeling demonstrated that vascular features clustered and could be differentiated in a sex-and injury-specific manner. Trajectory analysis confirmed that males displayed a more consistent disease trajectory compared to females after CHI.
Conclusions: A single concussion induced hyper-acute BBB and cerebrovascular perturbations in juvenile mice, which may presage long-term deficits during development. Importantly, sex differences in vascular TBI responses evident at PND17 emphasize the need to consider sex as an important variable in future pediatric TBI research.
A Weighted K-Nearest Neighbor Machine Learning Approach for Parcellating Brain Cortical Functional Regions in Finite Element Head Models
1Department of Mechanical and Materials Engineering, Western University, London, Canada, 2School of Biomedical Engineering, Western University, London, Canada
While contemporary neuroimaging increasingly interprets traumatic brain injury as distributed network-level dysfunction, current Finite Element (FE) head models remain limited in terms of anatomical partitioning. To mechanistically link impact-induced tissue deformation to functional network dysfunction, it is essential to compute biomechanical metrics within specific functional networks. Addressing this gap, this study framed atlas-to-mesh mapping into a discrete machine learning classification problem, developing a framework to project high-resolution neuroimaging networks onto FE meshes. Schaefer functional brain network parcellations (100- and 400-region) were mapped utilizing a distance-weighted K-Nearest Neighbor (KNN) classifier. This instance-based learning approach employed centroid-based geometric assignment with a tunable distance cutoff to prevent erroneous long-range predictions in areas with local atlas–mesh mismatch. Mapping quality was quantified using Dice Similarity Coefficient (Dice) and 95th-percentile Hausdorff Distance (HD95) across cutoffs (1–4.5 mm) and two FE mesh densities. A 3 mm geometric cutoff provided optimal performance, achieving a mean Dice of 0.82 and minimizing boundary error (mean HD95 = 1.42 mm) compared to a stricter 1 mm cutoff (Dice = 0.77; HD95 = 2.21 mm). Mesh density critically impacted high-resolution mapping and increasing element density improved mean Dice for the 400-region atlas from 0.82 to 0.85. The resulting boundary error aligns with acceptable variances reported in clinical 3D segmentation benchmarks. Ultimately, this scalable machine learning pipeline enables network-specific biomechanical analysis within computational models, providing an essential tool for translating physical head impact mechanics into the cognitive dysfunctions observed in clinical neurotrauma.
Acid-Base Derangements Correlate with Unfavorable Outcome After Traumatic Brain Injury: A TRACK-TBI ICU Cohort Study
1Department of Neurological Surgery, University of California San Francisco, San Francisco, United States of America, 2Department of Neurology, University of California San Francisco, San Francisco, United States of America, 3Department of Emergency Medicine, University of California San Francisco, San Francisco, United States of America
The impact of intensive care unit (ICU) management of physiologic parameters, including acid-base status, for traumatic brain injury (TBI) patients is understudied. The presence, duration, and treatment of exposure to acid-base derangements may be important disease modifiers. Using a single-center ICU cohort from the prospective U.S. TRACK-TBI Study (ClinicalTrials.gov #NCT02119182; N=69), we investigated associations between ICU acid-base derangements and six-month functional outcome (Glasgow Outcome Scale-Extended (GOSE)) post-TBI.
To overcome sparse sampling of acid-base status with traditional arterial blood gas (ABG) measurements, we recovered higher temporal resolution acid-base status from temperature-corrected end-tidal CO2 (ETCO2) anchored to ABGs. We calculated the time-normalized exposure to acid-base derangements across canonical acid-base classifications (metabolic acidosis/alkalosis; respiratory alkalosis/acidosis; normal range).
Multivariable logistic (GOSE=1-4 vs. GOSE=5-8) and ordinal regressions for six-month outcome incorporated IMPACT prognostic calculator scores, metabolic alkalosis burden, and their interaction.
Our cohort spent ≥60% of ICU time outside the normal range, which was underestimated by ABGs alone. The time-normalized burden of metabolic alkalosis was statistically associated with GOSE=1-4, independent of IMPACT score, on logistic (p=0.020) and ordinal regression analyses (p=0.004). Multiple imputation for missing data resulted in concordant findings.
Clinicians at the bedside currently optimize to PCO2 to conform with TBI management guidelines. Our data suggest that pH targets should be prioritized, and that a singular focus on PCO2 goals may not be adequate for personalized TBI treatment in the ICU nor for optimizing long-term post-TBI recovery. Our findings underscore that acid-base derangements, particularly metabolic alkalosis burden, are independent predictors of poorer outcomes.
Action Collaborative on Traumatic Brain Injury Care: Longitudinal Patient Characteristics from an Early Single-Center Post-Acute Clinic
1Department of Neurological Surgery, University of California, San Francisco, San Francisco, United States, 2Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital, San Francisco, United States, 3Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, United States, 4Department of Neurology, University of California, San Francisco, San Francisco, United States, 5Philip R. Lee Institute for Health Policy, University of California, San Francisco, San Francisco, United States, 6Medical College of Wisconsin, Milwaukee, United States, 7UCSF School of Medicine, University of California, San Francisco, San Francisco, United States, 8Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, United States, 9Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, United States, 10Department of Physical Therapy and Rehabilitation Science, University of California, San Francisco, San Francisco, United States, 11Department of Neurosurgery, University of Oklahoma, Oklahoma City, United States, 12Founder & Managing Director, Brain Care Catalyst, United States
A Post-Acute Traumatic Brain Injury (TBI) Care Clinic (PACC) was established as part of an emerging learning healthcare system (LHS) via the Action Collaborative on TBI. We sought to understand patient characteristics to improve LHS design and care delivery.
Along with clinical evaluation and management, patients completed the Neurobehavioral Symptom Inventory (NSI), Patient Health Questionnaire (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), Insomnia Severity Index (ISI), Headache Impact Test (HIT-6), and Dizziness Handicap Inventory (DHI) outcome (PRO) measures. Core clinical, biomarker, imaging, and modifier (CBI-M) features ≤24 hours from injury were recorded for patients evaluated after CBI-M publication.
Between 8/24/23-1/15/2026, patients age ≥ 18 completed baseline (n=439) and follow-up (F#) PROs: n=201 (45.8%), n=71 (16.2%), n=22 (5.0%), n=5 (1.1%), and n=1 (0.2%) (F1-F5, respectively). Acute CBI-M features were retrospectively ascertained for n=125, with Glasgow Coma Scale score of 13-15 for n=70/77 (90.9% of available scores), n=0 blood-based biomarkers, and n=72 (57.6%) with neuroimaging (51.4% with intracranial abnormality). Median baseline PRO scores were 26/88 (NSI, interquartile range 16-39), 9/27 (PHQ9, IQR 4.25-16), 6/21 (GAD7, IQR 2-12), 11/28 (ISI, IQR 6-17), 57/78 (HIT-6, IQR 46-64), 32/100 (DHI, IQR10-54), reflecting mild/subthreshold values except headache (substantial impact). At F1, all PRO scores were significantly improved from baseline (Wilcoxon signed-rank test, p<0.01) with differing patterns of recovery thereafter.
In an early LHS single-center TBI PACC, varying follow-up trajectories and PRO scores indicate the necessity of post-acute care. Next steps include systematic assessment of CBI-M features and longitudinal patient outcomes for real-world contextualization of PACC efficacy.
Acute Changes in Circulating MicroRNAs Indicate Neuronal Stress Following Repetitive Sub-Concussive Blast: INVICTA Study
1Henry M Jackson Foundation, Bethesda, United States, 2Uniformed Services University of the Health Sciences, Bethesda, United States
Up to 70% of blast exposure events in the military occur during training, and most are subconcussive. Although not typically associated with clinically diagnosed traumatic brain injury, repetitive sub-concussive blast exposure (RSCBE) has been linked to neurocognitive changes, persistent inflammatory blood marker alterations, and neuropathological changes. However, the long-term physiological impact of these exposures remains poorly understood. The INVICTA study is a 5-year prospective longitudinal investigation designed to quantify the effects of RSCBE during military heavy-weapon training.
We performed miRNA analysis on serum samples from Range Safety Officers (RSOs; n=22) and Active Controls (AC; n=23) using an OpenArray panel of 224 miRNAs implicated in neurodegenerative diseases. Validation samples were analyzed by ddPCR across acute time points after exposure (30 min, 6 hrs, 24 hrs, 72 hrs) and compared to baseline. Statistical significance was assessed by two-way paired ANOVA.
Two miRNAs showed significant group-by-time effects. miR-221-3p was decreased in RSOs compared to ACs at baseline (p=.046) and 6 hours post-exposure (p=.0026). miR-338-3p was also significantly reduced at 6 hours (p=.0001) and 72 hours (p=.0252) in RSOs compared to ACs. Both miRNAs have been associated with neuronal stress, inflammatory signaling, and axonal integrity, suggesting early molecular responses to repeated blast exposure.
These preliminary data indicate that circulating miRNAs may serve as early markers of RSCBE. Ongoing analyses will incorporate chronic time points, blast-gauge metrics, neurocognitive scores, and machine-learning approaches to evaluate exposure-biomarker interactions. Developing an integrated biomarker and exposure profile may improve risk assessment and support mitigation strategies for blast-exposed service members.
Acute CT Findings and Their Relation to Outcome in a Large Prospective Norwegian Cohort of Patients with Moderate and Severe Traumatic Brain Injury
1Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway, 2Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway, 3Department of Radiology, Møre and Romsdal Hospital Trust, Nordmøre and Romsdal Hospital, Molde, Norway, 4Department of Neurosurgery, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway, 5Clinic of Rehabilitation, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway, 6Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway, 7Department of Public Health and Nursing, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway, 8Department of Radiology, Vestre Viken Hospital Trust, Drammen Hospital, Drammen, Norway
Background: In a large prospective single-center cohort of patients with moderate and severe traumatic brain injury (TBI), we aimed to characterize acute CT findings and examine their association with 12-month outcome.
Methods: Standardized reports of acute CT findings from 784 patients (2004–2021) were analyzed by radiology residents or consultants. Outcome was assessed at 12 months using the Glasgow Outcome Scale–Extended (GOSE). Pairwise co-occurrence of CT findings was assessed using φ coefficients and hierarchical clustering. CT findings associated with outcome were identified using elastic-net penalized ordinal regression with age, Glasgow Coma Scale score and pupil dilation included as unpenalized covariates. Variables with non-zero coefficients were further examined by multivariable ordinal regression.
Results: Traumatic subarachnoid hemorrhage (tSAH) (77%) and subdural hematoma (70%) were the most frequent CT findings. Hierarchical clustering identified three principal clusters of intracranial pathology: 1) deep cerebral lesions (corpus callosum, brainstem, thalami or basal ganglia), 2) epidural and fracture-related pathology, and finally the largest 3) mass-effect cluster including subdural hematoma, midline shift and basal cistern compression. The five CT variables with the largest adjusted effect sizes for worse GOSE outcomes after elastic net penalization were non-visible basal cisterns (OR 9.1), compressed basal cisterns (OR 2.2), lesions in thalami or basal ganglia (OR 2.7), generalized edema (OR 1.5) and tSAH (OR 1.2).
Conclusion: We identified three distinct CT clusters, of which the mass-effect cluster comprised the most variables. Among numerous acute CT findings, basal cistern compression was particularly associated with worse long-term functional outcome after adjustment for established prognostic variables.
Acute CT Findings and Their Relation to Traumatic Axonal Injury on Early MRI in a Large Prospective Norwegian Cohort of Patients with Moderate and Severe Traumatic Brain Injury
1Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway, 2Department of Radiology, Møre and Romsdal Hospital Trust, Nordmøre and Romsdal Hospital, Molde, Norway, 3Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway, 4Department of Neurosurgery, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway, 5Clinic of Rehabilitation, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway, 6Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway, 7Department of Public Health and Nursing, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway, 8Department of Radiology, Vestre Viken Hospital Trust, Drammen Hospital, Drammen, Norway
Background: CT imaging detects only a minority of traumatic axonal injury (TAI) compared with MRI. We aimed to describe acute CT findings in a large prospective cohort of patients with moderate or severe traumatic brain injury (TBI) and assess their relation to TAI on early MRI.
Methods: Patients with moderate or severe TBI were included at a single center (2004–2021). Standardized CT reports were available for 784 patients; 305 underwent early MRI (<6 weeks). TAI severity was graded using the Trondheim TAI MRI grading (0–5). CT predictors were identified via elastic-net penalized ordinal regression with age, Glasgow Coma Scale score, and pupil dilation as covariates, and then further evaluated using diagnostic performance measures and multivariable ordinal regression.
Results: Elastic-net selection identified brainstem lesions (OR 15.9), thalamic or basal ganglia lesions (OR 2.2), punctate hemorrhages (OR2.0), intraventricular hemorrhage (IVH) (OR 1.9), and traumatic subarachnoid hemorrhage (tSAH) (OR 1.3) as CT variables predictive of increasing TAI grade. Punctate hemorrhages (n=54) showed 100% specificity but low sensitivity (23%) for TAI. Deep cerebral lesions (brainstem, thalami, or basal ganglia) were highly specific (97%) for higher TAI grades (3–5) but infrequent (n=20). IVH (87%) and tSAH (79%) showed moderate positive predictive value for TAI but limited negative predictive value for higher TAI grades (67% and 71%).
Conclusion: Punctate hemorrhages and deep cerebral lesions on CT were highly specific for TAI and high-grade TAI but showed low sensitivity. Most patients with TAI lacked these CT signs, highlighting the importance of early MRI for detection and grading.
Acute Imaging Strategy Patterns in Screened Emergency Department Patients with Traumatic Brain Injury
1University of Pennsylvania, Philadelphia, United States
Objectives: To assess emergency department (ED) utilization patterns of head CT (hCT) in the evaluation of traumatic brain injury (TBI) in a single Level 1 Trauma Center.
Methods: We analyzed hCTs ordered from the ED at Penn Presbyterian Medical Center from 07/2023 to 06/2024. Pan-scans were hCTs done as part of a whole-body scan. TBI was identified by abnormalities on the hCT and/or evidence of loss of consciousness, post-traumatic amnesia, confusion, or post-concussive symptoms (ACRM criteria). Injury mechanism, arrival Glasgow Coma Scale (GCS) score, neurosurgical consult time, and whether neurosurgical intervention occurred was recorded.
Results: 5,721 hCTs were ordered, of which 3,498 (62.9%) were suspected TBI. 304 (8.7%) showed TBI-related findings. 1,080 (30.9%) hCTs done for TBI were pan-scans. 735 patients with TBI were identified (median age 50 years [IQR, 35], 50.2% male), 304 (41.4%) by hCTs with trauma-related abnormalities and 431 by ACRM criteria despite normal hCT. Of the 304 abnormal hCTs, 174 (57.2%) were isolated hCTs and 130 (42.8%) were pan-scans. TBI-related abnormalities were found in 172 (7.1%) for isolated hCTs and 121 (11.2%) of pan-scans. Pan-scan use was highest for motor vehicle collisions [144 (64.6%)] and GCS 9-12 [27 (81.8%)]. Median arrival-to-neurosurgical consult time was 2.3 hours (IQR, 3.9). Neurosurgical intervention occurred in 35 (4.8%).
Conclusion: Over 30% of TBI evaluation hCTs in the ED were obtained as part of a pan-scan. Pan-scan use varied by injury mechanism and GCS, reflecting trauma imaging protocols. Implementation of biomarkers testing to minimize hCT use must account for these workflows.
Acute Physiological Effects of Diffuse Rotational Traumatic Brain Injury in Yucatan Miniature Swine
1University Of Pennsylvania, Philadelphia, United States, 2Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, United States, 3Neuroscience Graduate Group, Biomedical Graduate Studies, University of Pennsylvania, Philadelphia, United States
Yucatan miniature swine are widely used in translational traumatic brain injury (TBI) research due to their human-relevant gyrencephalic cortex and white-to-gray matter proportions. However, the acute physiological response to diffuse rotational TBI has not been systematically characterized, limiting the ability to distinguish injury-driven effects from anesthetic or procedural effects. This study characterized the immediate and subacute physiological responses to diffuse rotational TBI. Twenty female Yucatan miniature swine (7.05±0.72 months; 29.55±3.35 kg) were enrolled: 15 injured (one animal excluded due to inconsistent injury procedure, yielding 14 paired observations) and 5 sham controls. Heart rate, end-tidal carbon dioxide (ETCO2), peripheral oxygen saturation (SpO2), respiratory rate, and core temperature were recorded every five minutes. Within each injured subject, acute responses were assessed by comparing means from a 30-minute pre-injury window to a 30-minute post-injury window using paired t-tests. Physiological stability across injury conditions was evaluated by comparing vital signs at days 3, 7, and 14 to sham controls using one-way analysis of variance (ANOVA). TBI produced significant acute tachycardia (TBI: 120.8±14.3 vs. sham: 108.3±13.9 bpm; p=0.016; Cohen's d=0.74) and ETCO2 reduction (TBI: 43.9±3.6 vs. sham: 50.9±6.5 mmHg; p=0.017; Cohen's d=-1.24). SpO2, respiratory rate, and core temperature showed no significant changes. These acute changes in heart rate and ETCO2 were transient, as no physiological differences were detected between injured and sham subjects at subsequent timepoints (ANOVA; p>0.12), though small samples sizes limit conclusions. These acute cardiovascular changes are consistent with autonomic responses observed in clinical TBI, supporting the translational relevance of this model.
Adult Hypertension as a Clinically Relevant Comorbidity Augmenting Cognitive Deficits, Anxiety, and Pathological Outcomes After TBI in Pediatric and Adult Rats
1University Of Pittsburgh, Pittsburgh, United States
The prevalence of traumatic brain injury (TBI) necessitates post-injury cognitive and emotional assessments, especially considering overlapping comorbidities. We investigated how hypertension affects adult rats after pediatric TBI (pTBI) or adult TBI (aTBI) and hypothesized that comorbid hypertension worsens post-TBI cognitive performance. Male Spontaneously Hypertensive (SHR) and normotensive Wistar rats received a moderate controlled cortical impact or sham injury at 17 days or four months old. At five months old, the 3-Choice serial reaction time test (3-CSRT; sustained attention), T-maze attentional set-shifting (behavioral flexibility), open field testing (OFT; anxiety), and the shock-probe defensive burying test (SPDB; active and passive coping) assessed neurobehavior. In the pTBI cohort, TBI rats required longer 3-CSRT training, with normotensive TBI resulting in lower accuracy and higher omissions. SHR-pTBI rats showed greater distractibility (p<0.05). In the aTBI cohort, all TBI rats showed accuracy and omissions deficits on 3-CSRT, with SHR-aTBI rats demonstrating the greatest deficits and more impulsivity (p<0.05). SHR-pTBI rats showed impaired rule learning on the T-maze and set-shifting deficits when required to turn left, suggesting hemispatial neglect (p<0.05), and greater active avoidance in SPDB (p<0.05), indicating anxiety. SHR-aTBI rats displayed attentional deficits (specifically in accuracy and impulsivity) beyond either condition alone, and they approached and buried the probe less in SPDB (p<0.05). In the pTBI cohort, hypertension enlarged lateral ventricles, while TBI enlarged ipsilateral ventricles (p<0.05). SHR-pTBI rats showed disrupted colocalization of GFAP and aquaporin-4 in the dorsal hippocampus. These findings support assessing preclinical studies of comorbidities in TBI to enhance translatability and therapy development.
Advancing Global Data Sharing and Harmonization in TBI: Results from The International InTBIR Data Science and Harmonization Working Group
Dr. Stefania Mondello3,
1University Of Waterloo, Waterloo, Canada, 2University of California San Francisco, San Francisco, USA, 3University of Messina, Messina, Italy, 4Karolinska Institutet, Stockholm, Sweden
Objective: To identify priorities, challenges, and strategic actions required to enable global data sharing, harmonization, and interoperability in traumatic brain injury (TBI) research through an international consultation organized by the International Initiative for Traumatic Brain Injury Research (InTBIR) Data Science and Harmonization Working Group.
Methods: A global virtual workshop was organized using the World Café methodology to collect perspectives from multidisciplinary stakeholders. International experts from academia, clinical practice, funding agencies, and industry participated in structured discussions across four thematic domains, namely educational/landscape analysis, harmonization-interoperability, data sharing practices, and sustainability. Contributions from participants were collected during interactive sessions and through subsequent offline feedback. Discussion outputs were synthesized into key themes and recommendations.
Results: Participants emphasized the need for coordinated international leadership to develop educational resources, standardized frameworks, and practical tools supporting data harmonization. Major barriers to global TBI data sharing included regulatory differences across countries, lack of standardized data-sharing agreements, limited interoperability across databases, and insufficient infrastructure to support federated analysis. Priority actions identified were harmonizing existing datasets through retrospective approaches alongside the development of prospective standards for future studies, mapping and integrating existing repositories and initiatives, promoting interoperable data platforms, strengthening data curation practices, and establishing shared legal and ethical frameworks for data use.
Conclusion: Coordinated international efforts through InTBIR can play a central role in advancing global harmonization and interoperability in TBI research. The workshop outcomes provide a foundation for a strategic roadmap aimed at enabling large-scale data integration, strengthening global collaborative research, and accelerating progress in TBI.
Age-Adjusted Normative Data Improves Interpretation of Serum Neurofilament Light Associations with Neurologic and Extracranial Injury After Pediatric Traumatic Brain Injury
Mr. Tali Romero1, Dr. Jennifer Cooper1, Ms. Jasmine Gill1, Dr. Sara Mostafavi2, Dr. William Panenka1, Dr. Paul van Donkelaar1, Dr. Alexis Turgeon3, Dr. Keith Yeates4, Dr. Khosrow Adeli5, Dr. James Hutchison6, Dr. Sophie Stukas1,
1University Of British Columbia, Vancouver, British Columbia, Canada, 2University of Washington, Washington, Seattle, United States, 3Université Laval, Quebec City, Quebec, Canada, 4University of Calgary, Calgary, Alberta, Canada, 5Hospital for Sick Children, University of Toronto, Toronto, Ontatrio, Canada, 6Children’s Hospital of Eastern Ontario, University of Ottawa, Ottawa, Ontario, Canada
We aimed to characterize serum neurofilament light (NfL), a sensitive marker of neuroaxonal damage, across the pediatric TBI severity spectrum compared to reference intervals (RI). NfL RI were established using the Canadian Laboratory Initiative on Pediatric Reference Intervals cohort. NfL was measured in 130 children (87 GSC 13-15, 43 GCS 3-12) enrolled in the prospective, multisite, observational Canadian Biobank and Database for Traumatic Brain Injury (CanTBI) study. Pediatric inclusion criteria included: age 0-≤18 years at time of injury, presentation to hospital with TBI defined using Centre for Disease Control criteria, and collection of blood within 30 hours. Age-adjusted Z-scores were derived from RI and associations between NfL and clinical variables were evaluated using non-parametric methods. NfL correlated positively with hospital length of stay (ρ=0.609) and negatively with GCS (ρ=–0.640) and Pediatric Trauma Score (PTS) (ρ=–0.695) (all p<0.0001). NfL was elevated in participants presenting with loss of consciousness, peripheral fracture, and damage to the spine. Separated by GCS, NfL was higher in GCS 3-12 (56.1 pg/mL, Z=3.27) compared to GCS 13-15 (6.89 pg/mL, Z=0.90; p<0.001). Using Z>1.96, 29% of GCS 13–15 and 83% of GCS 3-12 exceeded this threshold. Elevated (>1.96) Z-scores in GCS 13-15 were associated with longer hospital stays, lower PTS, fracture, and loss of consciousness. In GCS 13-15, NfL was higher in CT-positive participants with intracranial injury (17.3 pg/mL, Z=2.46 vs 5.71 pg/mL, Z=0.63; p<0.001). NfL reflects injury severity and clinical burden, with age-adjusted Z-scores associated with unfavorable outcome despite substantial heterogeneity in milder injuries.
AI-Aided Triage for GSWH: Validating an Interpretable HCT-Based Mortality Model
1University Of Chicago, Chicago, United States, 2University of Oklahoma, Oklahoma City, United States, 3University of Cincinnati, Cincinnati, United States, 4Geisinger Health Systems, United States, 5Mechnikov Dnipropetrovsk Regional Clinical Hospital, Dnipro, Ukraine
Objectives: The goal of this study was to assess penetrating brain injury (PBI) patients through AI evaluation of head CT scans, particularly focused on complementing GCS as the clinical standard.
Methods: This single-center study retrospectively evaluated 222 CT scans obtained from unique patients who were admitted with PBI caused by gun shot wound to the head and met inclusion criteria. Of these, 106 (47.8%) lived and 116 (52.2%) died. An image-based multiple instance learning AI model (PBI-AI) was trained to predict mortality from initial CT scan acquisitions. In brief, PBI-AI extracted quantitative imaging features from individual CT slices, identified important information and aggregated features through attention pooling, and performed classification using patient mortality as the binary outcome variable.
Area under the ROC curve (AUC) was used as the primary performance metric, and model explainability and comparison with GCS were used for additional evaluation.
Results: The model achieved an AUC of 0.92 [0.87, 0.94] with optimal sensitivity and specificity of 0.88 [0.78, 0.97] and 0.87 [0.74, 0.96], respectively. This compares favorably with similar published models.
Further, inherent model interpretability allowed for both case-by-case and population level analysis of influential information within each CT scan. Regions of highest importance matched clinical expectation (cerebellum, midbrain). Visualization of model features through uniform manifold approximation and projection (UMAP) demonstrate association, but not perfect agreement, with GCS.
Conclusions: This study has demonstrated strong potential for AI in evaluating images acquired from patients with PBI, which is further verified by explainable AI output.
Alterations in Cerebral Blood Flow Associated with White Matter Hyperintensities Following Traumatic Brain Injury (TBI)
Dr. Alexa Walter1, Dr. James J. Gugger2, Dr. Linda Xu1, Stefanie Darnley1, Katie Brecker1, Priyanka Kalyani1, Amber Erich1, Justin Desprebiteres1, Trevor Mccutcheon1, Kate Deppen1, My Duyen Le1, Abbie Chan1, Daniel Brennan1, Dr. Andrea L.C. Schneider1, Dr. Danielle Sandsmark1, Dr. Ramon Diaz-Arrastia1
1University Of Pennsylvania, Ellicott City, United States2University of Rochester, Rochester, New York, United States
Objectives: To examine differences in cerebral blood flow (CBF) associated with white matter hyperintensities (WMHs) after TBI.
Methods: Fluid attenuated inversion recovery (FLAIR) and arterial spin labeling (ASL) sequences from TBI participants, at 2-weeks and 6-months post-injury, and healthy control (HC) participants were analyzed. WMHs were identified and segmented on FLAIR. WMH penumbra was identified by dilating WMH masks in 3 dimensions by 3 and 6 voxels. CBF within WMHs was compared with CBF in the homologous region of the contralateral hemisphere to provide intra-participant comparison. Group differences in CBF were analyzed using Wilcoxon sign-rank and rank-sum tests.
Results: 73 TBI participants were included (mean (SD) age: 39.74 (16.05) years, 79.5% male, 91.7% GCS 13-15, 54.79% head CT positive), 44 of whom returned at 6-months. 30 HC participants were included (34.36 (13.39) years, 66.7% male). Compared to HC, TBI participants had significantly higher WMH count at 2-weeks (TBI: median 15; HC 5.5; z=-2.64, p=0.008) and 6-months post-injury (TBI: 26.5; z=-3.64, p<0.001), as well as greater volume (2-weeks: z=-2.67, p=0.008; 6-months: z=-3.18, p=0.002). Mean CBF within WMHs was similar in TBI and HC. For both TBI and HC, mean CBF within WMHs was significantly lower than CBF of the homologous region of the contralateral hemisphere (z=-2.76, p=0.006). CBF was also significantly lower in WMH compared to the surrounding 3 and 6 voxel penumbra.
Conclusions: Reductions in mean CBF within WMHs suggest local hypoperfusion underlies this common radiologic finding. Hypoperfusion may also underlie the progression of WMHs over the first month’s post-injury.
Amnion Cell Secretome–Mediated Therapy for Repetitive Head Injury
Dr Scott Ferguson1,2, Mackenzie Browning1, Dr Daniel Paris1, Steven Bracco1, George Cottle1, Sc.D Larry Brown3, Dr Howard Wessel3, Tessa Vincennie1, Dr Fiona Crawford1,2,
1The Roskamp Institute, Sarasota, United States, 2James. A Haley Veterans' hospital, Tampa, United States, 3Noveome Biotherapeutics, Inc., Pittsburgh, United States
Background: ST266 has been evaluated in several Phase I/II clinical trials for non-neurological indications and has demonstrated a favorable safety profile, supporting its potential for translation to neurological disorders. Intranasal delivery enables direct transport to the central nervous system while bypassing the BBB. In this study, we assess whether ST266 exerts disease-modifying effects after traumatic brain injury by comparing continuous daily treatment for five months until euthanasia with a three-month treatment regimen followed by treatment cessation to determine whether therapeutic benefits persist after withdrawal.
Methods: Male and female C57BL/6 mice were randomly assigned to intranasal ST266 or vehicle starting one month after repetitive head impact (RHI). To assess potential disease-modifying effects, two treatment paradigms were compared: continuous daily treatment for five months until euthanasia, or three months of daily treatment followed by cessation. Neurobehavioral outcomes were evaluated using the Elevated Plus Maze, optomotor response, Rotarod, and Barnes Maze. Neuropathology evaluated GFAP, Iba1, and oligodendrocyte-associated tau pathology.
Results. ST266 significantly improved motor performance and reduced disinhibition-like behavior, with the most pronounced behavioral benefits observed in male mice. Neuropathological analyses at 6 months post-injury revealed chronic white matter pathology including axonal injury, oligodendrocyte alterations, astrogliosis, and microglial activation (CD45, CD68) that was attenuated by lifelong ST266 treatment. In vitro biochemical studies demonstrated that ST266 suppresses NF-κB activation and reduces pro-inflammatory cytokine production, including TNF-α, IFN-γ, and IL-12p70, in microglial cells.
Conclusion: These findings indicate that prolonged ST266 administration exerts anti-inflammatory and neuroprotective effects that mitigate chronic behavioral and neuropathological consequences of RHI.
Antagonist of Cellular Prion Protein Protects Learning and Memory in a Mouse Model of Traumatic Brain Injury
1Morehouse School of Medicine, Atlanta, United States, 2Department of Neuroscience, Yale School of Medicine, New Haven, United States, 3Department of Neurosurgery, Emory University School of Medicine, Atlanta, United States
Introduction: Cellular Prion Protein (PrPc) is implicated in Alzheimer disease (AD) pathogenesis. Chronic Traumatic Encephalopathy resulting from repetitive traumatic brain injury (rTBI) shares behavioral and histologic similarities to AD and may share a common biochemical mechanism. No US FDA (Food and Drug Administration) approved treatment or prophylaxis for patients with TBI exists. We aim to investigate PSCMA, an antagonist of PrPc, and its potential therapeutic benefit in a TBI mouse model.
Methods: Three-month old mice were placed in five groups, WT-, WT+Impact, WT+No Impact+PSCMA, WT+Impact+PSCMA pre and post treatment. Acquisition and probe trials of Morris Water Maze were utilized to establish baseline cognitive function. Mice received rTBI using closed cortical impacts and allowed six-week recovery. Reversal swim and probe trials were conducted to assess learning and memory. Behavioral analysis was performed following probe trials.
Results: Mice showed no difference in latency to platform or time in target quadrant during baseline assessment. After impaction, and recovery WT+Impact showed greatest latency to platform, while unimpacted controls showed the shortest in reversal swims. Impacted pre and post treatment showed intermediate latency to platform which was statistically different compared to unimpacted controls (p < 0.01). Probe trials showed all treatment groups spent more time in target when compared to WT+Impact (p<0.01).
Conclusion: Impacted treatment groups showed superior performance in spatial memory tasks compared to WT+Impacted cohort. Our findings suggest that learning and memory can be protected with administration of PSCMA before or after TBI.
Assessing First Responder Perceptions About Gunshot Wounds to the Head (GSWH)
Elaine Lo1,
1University of Chicago, Chicago, United States
Objective: Gunshot wounds to the head (GSWH) usually require immediate triage and resuscitation on scene by first responders, but little research has explored this prehospital care. We hypothesized that emergency medical service (EMS) providers may develop a nihilistic outlook on GSWH survivability. This study sought to elicit EMS provider perceptions of GSWH survivability and its potential impact on decision-making and care delivered in the prehospital setting.
Methods: We conducted a series of focus groups, using a standardized guide, with a convenient sample of EMS providers recruited from a single, urban, Level 1 Trauma Center. Participants were asked about GSWH survivability, factors affecting decision making and care delivery in the field, and emotional impact of GSWH cases. Dyads of coders independently coded each transcript using a codebook derived from the guide, with codes added as needed.
Results: Five focus groups were held with 16 EMS providers. All participants (69% male; 69% white, 13% black, 13% Hispanic) were paramedics in the Chicago Fire Department EMS with at least one year of experience (median [Q1-Q3] 9 [6,15] years), and 88% had prior GSWH field exposure. Common themes included (1) Concerns about scene control and personal safety; (2) Overwhelming perception of poor prognosis; (3) Resource limitations in the field, and (4) Lack of follow-up about patient outcomes.
Conclusion: In addition to EMS perception of poor prognosis, issues of scene control, personal safety, victim count, and limited resources impact GSWH field care. Clinical decision-making factors varied considerably, and participants reported scarce follow-up on patient outcomes.
Assessing Kinematic Fidelity of Head Movement During a Rotational Acceleration Traumatic Brain Injury in Pigs
1Center for Brain Injury & Repair, Department of Neurosurgery, University of Pennsylvania, Philadelphia, United States, 2Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, United States, 3Department of Bioengineering, University of Pennsylvania, Philadelphia, United States, 4Center for Injury Research and Prevention, Children’s Hospital of Philadelphia, Philadelphia, United States, 5Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
Traumatic brain injury (TBI) affects 69 million people annually and is most frequently caused by rapid rotational acceleration of the head. Modeling rotational injuries in pigs can employ biomechanical parameters scaled from humans, allowing researchers to answer basic and translational questions about clinical pathology. However, precisely describing head kinematics during rotational acceleration injuries is imperative to understand the relationships between biomechanical parameters, pathology, and neurological outcomes. Using the established HYGE model of rapid rotational acceleration, we examined kinematic transfer efficiency during rotational acceleration by assessing how closely the motion of the subject’s head matched the motion of the rotational device. Pigs were subjected to head rotation in the sagittal plane (n=5). Kinematics were recorded with angular velocity transducers and high-frame-rate videography, which was quantified with the deep learning neural network, DeepLabCut. The rotational device was programmed to generate peak angular velocities ranging from 86.3 - 108.5 rad/s. The kinematic coupling of peak angular velocities between the head and the rotational device was 94.6% ± 3.4% (mean ± SD) across the range of angular velocities, suggesting a high kinematic transfer efficiency. These angular velocity and acceleration levels exceeded clinical concussion thresholds based on appropriate mass scaling. These findings provide critical insights into the fidelity of large-animal rotational acceleration injury by enhancing our understanding of force transmission and head kinematics, leading to more accurate scaling and representation of human TBI events.
Assessing Outcomes of an Institutional Protocol for Antibiotic Prophylaxis for Civilian Cranial Gunshot Wounds
1College of Medicine, University of Cincinnati, Cincinnati, United States, 2Department of Neurosurgery, University of Cincinnati, Cincinnati, United States, 3Department of Neurology & Rehabilitation Medicine, University of Cincinnati, Cincinnati, United States
Cranial gunshot wounds (cGSW) remain a leading cause of penetrating traumatic brain injuries (pTBI), with variable rates of intracranial infection (1% to 59%) reported in the literature. Current guidelines support the use of prophylactic antibiotics in the setting of pTBI, however, there remains debate on agent selection and duration of therapy. We aimed to evaluate the feasibility, safety, and clinical impact of implementing a routine antibiotic prophylaxis protocol in a sequential cohort of patients who presented to our Level 1 trauma center with cGSWs from March 2021 to July 2025. Our protocol calls for initiation of a single third-generation cephalosporin within 24 hours of admission for a five-day course. Infection rates were compared to a propensity-matched historic cohort from the pre-protocol era with heterogenous antibiotic use. Fifty-six patients met inclusion criteria. There was a high rate of protocol adherence (95%) and very few adverse drug events (diarrhea; 7.1%). We observed three cranial infections, at a median of 44 (IQR 32, 46) days from injury and nine nosocomial infections with pneumonia being most common. On multivariable regression, CSF leak was associated with the development of cranial infection (OR 8.47; 95% CI 0.89-104.6). Though limited by study power, we observed fewer infectious complications (3; 5.3%) following adoption of our antibiotic protocol compared to the matched cohort (5; 8.9%) from six years prior to protocol implementation (p = 0.468). Overall, our study provides evidence for the efficacy, safety, and feasibility of implementing a single antibiotic protocol for prophylaxis in patients with cGSW.
Association of Systemic Hospital Complications with Functional Disability After Moderate to Severe Traumatic Brain Injury: A TRACK-TBI Study
1Department of Neurological Surgery, University of California San Francisco, San Francisco, United States, 2Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital and Trauma Center, San Francisco, United States, 3Weill Institute for Neurosciences, University of California San Francisco, San Francisco, United States, 4Department of Neurological Surgery, Medical College of Wisconsin, Milwaukee, United States, 5Rush University Medical College, Chicago, United States, 6Departments of Neurological Surgery and Biostatistics, University of Washington, Seattle, United States, 7Department of Neurology, University of Pennsylvania, Philadelphia, United States, 8Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, United States, 9School of Medicine, University of Missouri-Kansas City, Kansas City, United States, 10New York University Grossman School of Medicine, New York City, United States, 11University Neurosurgical Center Holland, Leiden University Medical Center, Haaglanden Medical Center, Leiden-The Hague, The Netherlands, 12Department of Surgery, Division of Neurosurgery, QEII Health Sciences Center and Dalhousie University, Halifax, Canada, 13Department of Neurology, Medical College of Wisconsin, Milwaukee, United States, 14Department of Surgery, Vanderbilt University Medical Center, Nashville, United States, 15Department of Emergency Medicine, University of California San Francisco, San Francisco, United States, 16Department of Neurological Surgery, Baylor College of Medicine, Houston, United States, 17Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, United States, 18Department of Rehabilitation Medicine, Spaulding Rehabilitation Hospital, Charlestown, United States, 19Department of Psychiatry, Massachusetts General Hospital, Boston, United States, 20 Institute of Health Policy Studies, University of California San Francisco, San Francisco, United States
Introduction: Systemic in-hospital complications after moderate to severe traumatic brain injury (msTBI) are associated with greater hospital length of stay (HLOS) and in-hospital mortality, but their role in longitudinal recovery is not well-characterized. We investigated whether hospital complications are associated with poorer acute and longitudinal outcomes in the first year post-msTBI.
Methods: The TRACK-TBI Study enrolled TBI patients presenting to 18 U.S. Level 1 trauma centers within 24-hours. The current analysis included patients aged ≥17-years with Glasgow Coma Scale (GCS)=3-12, intracranial hemorrhage on computed tomography, intensive care unit admission, and complete complication records. Multivariate regressions evaluated associations between complications and acute (HLOS, discharge status) or longitudinal (Glasgow Outcome Scale-Extended [GOSE] score) outcomes, adjusting for age, sex, GCS, Marshall score, intracranial surgeries/procedures, extracranial injury, and pre-existing conditions. Multivariate hazard ratios (mHR; [95% CI]) and multivariate odds ratios (mORs; [95% CI]) were reported.
Results: Of 392 patients (76% GCS=3-8), 56% had ≥1 in-hospital complication(s). Complications were associated with elevated HLOS (cardiovascular mHR=1.49, gastrointestinal mHR=1.76, infection mHR=1.73, and pneumonia mHR=1.54) and discharge non-home (hematologic mOR=4.43, infection mOR=5.08, and pneumonia mOR=2.57). Longitudinally, pneumonia (mOR=3.28[1.59-9.59]; p=0.036) and infection (mOR=11.67[1.31-103.79]; p=0.028) at 2-weeks; neurological (mOR=2.23[1.04-4.79]; p=0.040), pneumonia (mOR=1.86[1.01-3.84]; p=0.045), and infection (mOR=2.19[1.01-4.74]; p=0.047) at 3-months; gastrointestinal (mOR=6.54[1.59-26.83]; p=0.009) at 6-months; and cardiovascular (mOR=4.91[1.34-17.93]; p=0.016) and pneumonia (mOR=1.98[1.04-3.79]; p=0.039) at 12-months were associated with death/severe disability (GOSE=1-3).
Discussion: msTBI patients with infection, pneumonia, gastrointestinal, neurologic, and cardiovascular complications are at elevated risk for death/disability within 12-months postinjury. These findings highlight the need for early detection and intervention.
Associations of Neurotrauma History with Parkinsonism and Lewy Body Dementia Clinical Features in Former NFL Players at Late Life
1Department of Neurosurgery and Neurology, Medical College Of Wisconsin, Milwaukee, United States, 2Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, United States, 3Departments of Emergency Medicine and Pediatrics, Harvard Medical School, Boston, United States, 4Division of Emergency Medicine, Boston Children’s Hospital, Boston, United States, 5University of Missouri Kansas City, Kansas City, United States, 6Department of Kinesiology, Michigan State University, East Lansing, United States, 7The Micheli Center for Sports Injury Prevention, Boston Children's Hospital, Waltham, United States
Objectives: Greater neocortical Lewy Body disease (LBD) has been reported in those with higher contact sport exposure. In vivo Parkinsonism associations with contact sport exposure have been variable. This study characterized Parkinsonism and LBD clinical features and examined associations with neurotrauma history in former professional football players at late life.
Methods: Former players (N=171; Mage=60.12±6.19) were evaluated using the Movement Disorders Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) Part-III and completed questionnaires including: concussion history, Cumulative Head Impact Exposure Estimate (CHII), select REM-sleep behavior disorder questions, and Neuropsychiatric Inventory-Questionnaire (NPI-Q). Descriptive statistics characterized clinical features of Parkinsonism and LBD. Logistic regression models examined associations with neurotrauma history.
Results: MDS-UPDRS Part-III scores were mild with a median score of 1 (IQR=0,5; range=0-26). A notable percentage of players endorsed REM-related sleep disruption symptoms including leg cramping at night (n=73; 43.7%), needing to get up and move legs at night (n=47; 28.1%), and having unusually vivid or bizarre dreams (n=47; 28.7%). Four (2.5%) participants reported visual hallucinations. Compared to those with low concussion history, participants with 15+ concussions were more likely to endorse leg cramping at night (p=.013; B=1.27, SE=0.51). Associations between neurotrauma history with MDS-UPDRS total scores or other sleep behavior items (Ps>.05) were not observed.
Conclusions: Associations between neurotrauma history with Parkinsonism and LBD clinical features were limited, though a select feature of atypical sleep symptomology was associated with very high concussion history. Ongoing monitoring of clinical features and their potential association with post-mortem findings related to neurotrauma history is needed.
Associations of Traumatic Brain Injury with Incident Cardiovascular Disease: Results from the Atherosclerosis Risk in Communities (ARIC) Study
1Thomas Jefferson University, Philadelphia, United States, 2University of Pennsylvania-Perelman School of Medicine, Philadelphia, USA, 3Harvard Medical School, Cambridge, USA, 4Emory University, Atlanta, USA, 5Johns Hopkins School of Medicine, Baltimore, USA
Objective: To examine associations of traumatic brain injury (TBI) and incident coronary artery disease (CAD), heart failure (HF), and atrial fibrillation (AF) among community dwelling older adults.
Methods: 12,238 Atherosclerosis Risk in Communities (ARIC) Study participants without prevalent TBI, CAD, HF, or AF at study baseline (1987-1989) were included. TBI history (frequency and severity), was ascertained via self-report and ICD-9/10 codes. Incident CAD was identified through physician-adjudicated medical records and death indices, while incident HF and AF were identified using ICD-9/10 codes. Cox proportional hazards models were used to estimate associations of time-dependent TBI with incident cardiovascular outcomes, adjusting for sociodemographic and cardiovascular risk factors.
Results: At baseline, participants were mean age of 54 years, 58% were female, and 28% self-reported as Black. Over a median follow-up of 26 years, there were 1,985 incident CAD events, 3,165 incident HF events, and 2,769 incident AF events. In adjusted models, compared to individuals without TBI, individuals with TBI had 1.23 (95%CI=1.05-1.45) times the rate of incident CAD, 1.38 (95%CI=1.24-1.55) times the rate of incident HF, and 1.21 (95%CI=1.07-1.37) times the rate of incident AF. There was evidence for dose dependent associations of TBI frequency and severity with incident HF, but the rates of incident CAD and incident AF were not meaningfully different by TBI frequency or severity.
Conclusions: TBI sustained in mid-to-late adulthood is associated with elevated risk of incident cardiovascular disease. These individuals represent a high-risk subgroup who may benefit from targeted cardiovascular risk factor prevention and modification.
Astrocytic Tau Pathology Differentiates Early Onset Alzheimer’s Disease Associated with Traumatic Brain Injury
1Department of Laboratory Medicine, University of Washington, Seattle, United States, 2Neuroscience Graduate Program, University of Southern California, Los Angeles, United States, 3Office of Chief Medical Examiner of the City of New York, New York, United States, 4Gladstone Institute of Neurological Disease, San Francisco, United States, 5Universidade Federal de Minas Gerais, Departamento de Clínica Médica, Faculdade de Medicina, Grupo de Pesquisa em Neurologia Comportamental e Cognitiva, Belo Horizonte, Brazil, 6Departments of Laboratory Medicine and Pathology and Neurosciences, Mayo Clinic, Jacksonville, United States
Astrocytes are vital cells in the brain that contribute to maintaining neural circuits. Like neurons, astrocytes can accrue abnormal protein deposits with aging and neurodegenerative disease. Phosphorylated tau accumulates in astrocytes, the most common version seen in the form of thorn-shaped and granular/fuzzy astrocytes, collectively referred to as aging-related tau astrogliopathy (ARTAG). These same tau-laden astrocytic morphologies frequently accompany the sulcal lesions of chronic traumatic encephalopathy (CTE) – a pathology associated with head injury. An early age of onset is also associated with Alzheimer’s disease in the context of traumatic brain injury (TBI). Thus, we hypothesized that early onset Alzheimer’s disease (EOAD) with a history of TBI would be more likely to have ARTAG pathology along with a wider distribution throughout the brain compared to EOAD without TBI. We analyzed ARTAG pathology across three cohorts: early-onset Alzheimer's Disease, late-onset Alzheimer’s disease (LOAD), and no dementia, from brain donors with and without TBI, including cases from three studies and two institutions (Adult Changes in Thought (ACT) Study, UW Alzheimer’s Disease Research Center, and the UCSF Alzheimer’s Disease Research Center (aka. Neurodegenerative Brain Bank)). The presence of thorn-shaped and granular/fuzzy astrocytes throughout cortical and subcortical regions was identified and analyzed with multivariable logistic regression. We found a significant association with TBI for ARTAG presence in the anterior cingulate and angular gyrus, as well as for white matter, subpial and perivascular subtypes, specifically in EOAD cases with minimal effects for TBI in the LOAD and no dementia cases.
AT 035, a NOP Receptor Partial Agonist, Enhances Recovery After Repeated Closed Head Traumatic Brain Injury with and Without Prior Stress
1The University of Oklahoma, Oklahoma City, United States
Repeated closed-head (CH) TBI produces persistent neurological and sensory deficits in up to 20% of patients and often noted comorbidly with PTSD. There are no FDA-approved disease-modifying therapies for TBI, and only two for PTSD. Previous studies found that NOP receptor modulation improved PTSD and CCI-TBI symptoms. To test if prior traumatic stress further exacerbates recovery from CH-TBI outcomes and if NOP receptor modulation with AT-035 improves neurological and affective outcomes, male Sprague-Dawley rats (N=10—14/group) received 3 CHI-TBI impacts over 5 days with or without 7 day prior exposure to the single prolong stress (SPS) PTSD model or sham TBI. AT-035 (1 mg/kg, i.p., 1x daily) or vehicle was administered for 7 days beginning 1 hour post first impact (PFI) first impact; outcomes were assessed over 21 days PFI.
Modified Neurological Severity Scores (mNSS), time on rotarod, thermal and tactile sensitivity significantly worsened in both TBI and TBI+SPS rats compared to sham and persisted for at least 21 days. Rats in the polytrauma group exhibited greater thermal hyperalgesia than TBI alone, but rotarod and mNSS deficits and tactile allodynia were similar. AT-035 significantly improved scores in all groups, but improvements were not always as rapid with polytrauma, or to the same extent as TBI. However, AT improved open arm time in SPS+TBI rats more than TBI.
These findings indicate that early NOP receptor modulation yields significant functional benefits after TBI or TBI+SPS, supporting AT-035 as a promising candidate for disease-modifying treatment of mild TBI with or without polytrauma.
Autonomic Reflex–Induced NRF2 Activation Prevents Secondary Injury in Traumatic Brain Injury
1The Feinstein Institutes for Medical Research, Manhasset, United States
Background: Traumatic brain injury (TBI) triggers oxidative stress within minutes, disrupting p62–KEAP1–NRF2 signaling to drive neurodegeneration. NRF2, the master regulator of antioxidant and cytoprotective genes, remains underutilized in TBI, possibly because electrophilic activators fail in an already exhausted redox environment. The diving reflex (DR), or oxygen conserving reflex, a trigeminal nerve–mediated autonomic response, may enable non-electrophilic NRF2 activation.
Methods: In 252 male Sprague-Dawley rats with controlled cortical impact TBI, we compared natural DR (breath-hold diving), trigeminal nerve stimulation–induced DR (TNS), and CGRP supplementation against the electrophilic activator dimethyl fumarate (DMF). Interventions were delivered at 3 h post-injury, coinciding with peak oxidative stress. Over 28 days, we assessed NRF2 nuclear translocation and phosphorylation, p62–KEAP1 axis dynamics, glutathione levels, lipid peroxidation, lesion volume, and sensorimotor, anxiety, memory, and pain behaviors.
Results: DR rapidly reactivated the p62–KEAP1–NRF2 axis via CGRP-mediated p62 Ser351 phosphorylation, and halted lipid peroxidation. Natural DR, TNS, and CGRP reduced lesion volumes by 32%, 39%, and 23% respectively, and significantly improved sensorimotor, cognitive, affective, and nociceptive outcomes (all p < 0.05). In contrast, DMF though enhancing NRF2 nuclear levels, further depleted glutathione, aggravated oxidative injury, and failed to improve or even worsened histological and functional endpoints.
Conclusions: DR via physiological diving, electrical stimulation, or CGRP pharmacology, provides the first non-electrophilic approach to activate NRF2 in TBI. By harnessing the CGRP–p62–KEAP1–NRF2 axis during peak oxidative stress, DR delivers robust neuroprotection and multi-domain functional recovery where electrophilic activators fall short.
Acknowledgements: Supported by USAMRAA award #HT9425-24-1-1017.
Axon Fiber Orientation Predicts Region-Specific Axonal Vulnerability in Traumatic Brain Injury: A Mechanistic Basis for Selective White Matter Damage
1Department of Mechanical and Materials Engineering, Western University, London, Canada, 2School of Biomedical Engineering, Western University, London, Canada, 3Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Canada
Diffuse axonal injury (DAI) is a hallmark pathology of traumatic brain injury (TBI). Postmortem and neuroimaging studies consistently reveal that DAI selectively targets the corpus callosum and internal capsule, yet the biomechanical basis for this regional predilection remains unexplained. We hypothesized that axon fiber orientation relative to the direction of mechanical strain is the primary independent determinant of region-specific axonal susceptibility.
We employed a whole-brain mouse finite element model with anatomically resolved vasculature and axon tracts from diffusion magnetic resonance imaging tractography, a well-established platform for controlled TBI research. Axonal strain responses were examined across three rotational planes and two loading severities representing mild to moderate/severe TBI. A simplified tensile validation model confirmed a near-perfect linear relationship between fiber orientation angle and axon strain amplification (R2 = 0.97).
In the whole-brain model, fiber orientation angle consistently and linearly predicted the axon-to-brain strain ratio across all loading conditions, with strong correlations in the corpus callosum (R2 = 0.65–0.70) and stronger relationships in the internal capsule (R2 = 0.75–0.89), consistent with its highly organized projection fiber architecture. Meanwhile, axons parallel to head rotational axes developed minimal axial strains.
This study provides the first quantitative framework linking fiber directionality to region-specific axonal vulnerability in a rodent TBI model, offering a mechanistic explanation for selective white matter damage observed clinically. By establishing fiber orientation as an independent predictor of axonal injury risk, this framework supports future translation to human TBI studies, potentially informing injury-threshold criteria and complementing diffusion tensor imaging-based biomarkers for DAI assessment.
Axonal Stretch Injury Induces Oma1 Activation and Disrupts Mitochondrial Dynamics
1University of Michigan Medicine, Ann Arbor, United States, 2Michigan Neuroscience Institute, Ann Arbor, United States, 3Department of Emergency Medicine, Ann Arbor, United States, 4Department of Molecular and Integrative Physiology, Ann Arbor, United States, 5Neuroscience Graduate Program, Ann Arbor, United States
Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. Secondary injury mechanisms following head trauma—including energy deficit, excitotoxicity, and ionic imbalance—contribute to neuronal death that occurs minutes to years after injury. Mitochondria play a central role in neuronal homeostasis and energy production through regulated cycles of fission and fusion mediated by Drp1 and Opa1, collectively termed mitochondrial dynamics. We hypothesize that disruption of these regulators contributes to neuronal death following TBI. To test this, we used an in vitro model of axonal stretch injury (ASI) that replicates the mechanical forces of head trauma. Primary mouse cortical neurons cultured on silicone membranes were subjected to uniaxial strain to stretch neuronal cell bodies and processes. Mitochondrial morphology was assessed up to 24h post-ASI using confocal microscopy and a validated machine learning classifier. Cell viability was measured using a lactate dehydrogenase assay, and mitochondrial dynamics proteins were quantified by western blot. ASI induced punctate and swollen mitochondrial morphology (n = 3–4, p < 0.05), increased Drp1, and enhanced Oma1-mediated cleavage of Opa1 (sOpa1) 2–4h post-injury (n = 3–4, p < 0.01). Cell death increased up to 4h (n = 3, p < 0.05). Translational validation in mice subjected to controlled cortical impact revealed increased Oma1 activation and sOpa1 (n = 5, p < 0.05). Oma1 knockout neurons showed increased baseline mitochondrial networking that developed injury-induced fragmentation and upregulated Drp1 with decreased cell death. These findings identify Oma1 activation as a key driver of mitochondrial dysfunction following TBI.
Baroreflex Sensitivity and Dynamic Cerebral Autoregulation after Acute Traumatic Brain Injury: Disentangling Brain-Specific and Systemic Trauma Effects
1UT Southwestern Medical Center, Dallas, United States, 2Institute for Exercise and Environmental Medicine, Dallas, United States, 3Presbyterian Hospital Dallas, Texas Health Resource, Dallas, United States, 4Parkland Health, Dallas, United States, 5Mayo Clinic, Rochester, United States
Dynamic cerebral autoregulation (dCA), cardiac baroreflex sensitivity (BRS), and their interrelationships play the key roles in cerebral blood flow regulation, yet their behaviors in the acute traumatic brain injury (TBI) remain poorly defined. This cross-sectional study aims to characterize BRS, dCA, and their interrelationships in acute TBI (<7 days post-injury). Forty TBI patients (age 38±18 yr, 40% female), 11 non-TBI orthopedic trauma controls (OTC, age 41±16 yr, 45% female), and 25 age- and sex-matched-healthy controls (age 41±18 yr, 44% female) were included. Beat-to-beat heart rate, blood pressure, and middle cerebral artery mean blood velocity (MCA Vm) were continuously recorded at rest. Transfer function analysis (TFA) was used to quantify BRS (systolic blood pressure→R-R interval) and dCA (mean arterial pressure→MCA Vm). BRS gain in the low-frequency (LF) band (0.07–0.15 Hz) was lower in the TBI group compared with the OTC and matched-controls (P = 0.040). dCA gain across all frequency bands (0.07-0.35 Hz) was lower in both TBI and OTC groups relative to the matched controls (P ≤ 0.001). Covariate-adjusted partial correlation analyses showed a positive correlation between BRS LF gain and dCA LF gain (0.07-0.20 Hz) in OTC (r = 0.912, P = 0.031) and matched-controls (r = 0.524, P = 0.018), but not in the TBI group (r = 0.141, P = 0.473). These findings suggest that brain-specific trauma impairs BRS and leads to absence of the interrelationships between BRS and dCA, whereas dCA alterations may reflect both brain-specific and systemic responses to acute traumatic conditions.
Basic Needs Screening for Emergency Department Neurotrauma Patients
1Medical College of Wisconsin, Milwaukee, United States
Background: There is increasing recognition that healthcare settings should screen for patients’ basic needs; however, it is unknown which basic needs are most relevant to mTBI patients as well as how emergency department (ED) providers can most effectively screen for and address these. Here, we aimed to determine the prevalence of basic needs in a sample of patients with traumatic causes of injury.
Methods: Patients with traumatic causes of injury were enrolled during their visit to the emergency department (ED) at Southeast Wisconsin’s Level I Trauma Center. Participants completed basic needs questionnaires, and the prevalence of basic needs were quantified and compared by type of injury using binary logistic regression and inverse probability weights.
Results: A total of 220 ED patients with traumatic causes of injury (n=107 mTBI, n=113 trauma control [TC]) were enrolled. 158 patients (71.8%) endorsed insecurity in at least one domain, with many (41.1%) requesting resources from the study team. The most frequently endorsed insecurities were those involving finances (80 patients [36.3%]), food (83 patients [37.5%]), and living situation (65 patients [30.2%]). The prevalence of positive screens for individual domains was not significantly different between groups.
Conclusion: Our results highlight the necessity of basic needs screening in ED settings and contribute to a growing understanding of commonly unmet domains. Future directions of this study will explore the longitudinal changes in needs after ED discharge and the impact of injury type on these needs over time.
Bedside Electromagnetic Neuronavigation to Advance Precision and Safety for Cranial Access Procedures: Proof-of Principle Study in Neurotrauma and Neurocritical Care
Dr. Alexander Aabedi1, Mr. Youssef Sibih1, Dr. David Caldwell1, Ms. Maria Velasco1, Dr. Edilberto Amorim1, Dr. Alexander Haddad1, Dr. Daniel Chang1, Dr. Jason Chung1, Dr. Maxwell Wang1, Dr. Robert Osorio1, Mr. Lawrence Chyall1, Dr. Cathra Halabi1, Dr. H. E. Hinson1, Dr. Rajiv Saigal1, Dr. Anthony DiGiorgio1, Dr. Michael Huang1, Dr. Phiroz Tarapore1, Dr. Geoffrey Manley1,
1University Of California, San Francisco, San Francisco, United States
Objectives: Bedside cranial access devices, including external ventricular drain (EVD), subdural evacuation port system (SEPS), and intracranial pressure monitor (ICPM), are foundational to neurotrauma/neurocritical care. Craniometric-based placement techniques may be limited by aberrant anatomy, clot-filled ventricles, and/or complex extra-axial collections. Bedside electromagnetic (EM) neuronavigation registered to computed tomography imaging may enable precise targeting and peri-procedural risk reduction, without requiring operating room transport or rigid cranial fixation.
Methods: We retrospectively reviewed consecutive patients who underwent bedside cranial procedures using Stealth EM neuronavigation (Medtronic) from 11/2025-01/2026 at a single-center neurocritical care unit. Neuronavigation was used for distorted intracranial anatomy, atypical targets, and/or high consequences of imprecision. Outcomes included immediate procedural function, post-procedure imaging confirmation, need for revision, and procedure-related complications.
Results: Eight patients underwent 12 EM-navigated bedside procedures (8 EVDs, 2 SEPS, 2 intraparenchymal ICPMs). Indications included aneurysmal subarachnoid hemorrhage, traumatic brain injury, ventriculitis with ventricular trapping, obstructive hydrocephalus, diffuse cerebral edema, and complex postoperative or membrane-rich subdural collections. Neuronavigation enabled precise bedside trajectory planning for dual-catheter placement to access non-communicating ventricular compartments, and targeted SEPS placement at regions of maximal subdural collection thickness. All procedures achieved immediate intended function and post-procedure imaging confirmation. There were no attributable complications or post-procedural revisions.
Conclusions: Our proof-of-principle series showed bedside EM neuronavigation was feasible, safe, and readily integrated into neurocritical care workflows for high-risk cranial access. This approach may improve procedural precision, support trainee education through real-time image-based supervision, and reduce transport or operative needs of neurologically or hemodynamically unstable patients. Validation studies are needed.
Beyond Demographics: Diffusion MRI Improves Prediction of Cognitive Outcome After TBI
1Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States, 2Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States, 3Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States, 4Department of Neurosurgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States
Objective: Numerous TBI patients with GCS13–15 and CT-negative develop persistent cognitive impairment. Current outcome prediction models rely primarily on clinical/demographic variables. We aim to test whether diffusion MRI (dMRI) improves 1-year cognitive outcome prediction beyond these variables.
Methods: We analyzed 424 controls (TRACK-TBI, IXI) and 187 patients (TRACK-TBI, GCS13–15, CT-negative) with dMRI at 2-weeks and 6-months post-injury and 1-year cognitive outcomes. Poor cognitive outcome was defined as cognitive impairment (<9th percentile) or cognitive decline (>90% reliable change index) in any score across two domains, based on 5 cognitive scores.
Each individual was characterized by mean diffusivity from 84 white matter (WM) regions, age- and sex-corrected and standardized using controls. A normative WM microstructural space was defined from control microstructural measures, and a Microstructural Abnormality Index (MAI) was computed for each patient, as Euclidean distance from the normative space.
Baseline demographic/clinical variables were selected using backward stepwise logistic regression(p<0.2). Support vector machine models were trained using clinical/demographic variables from the same timepoint as imaging with and without MAI. Model performance was evaluated across 200training/hold-out iterations with 5-fold cross-validation. Area under the curve(AUC) was compared using DeLong test.
Results: Selected clinical/demographic measures included depression (SWLS), sex, race, health insurance status, and symptom burden (RPQ). At 2-weeks, clinical/demographic-only models achieved AUC=0.65±0.10; adding MAI increased AUC to 0.75±0.09(p<0.01). At 6-months, performance improved from 0.68±0.08 to 0.73±0.08(p<0.01).
Conclusions: MAI significantly improved prediction of 1-year cognitive outcome beyond clinical/demographic measures. These findings show that subtle microstructural abnormalities detected early after injury carry prognostic information, supporting MAI as early dMRI-based biomarker for risk stratification in CT-negative TBI.
Beyond Glasgow Coma Scale: Applying the Comprehensive Brain Injury Model to Pediatric Traumatic Brain Injury
1Children's Healthcare of Atlanta, Atlanta, United States, 2Georgia Institute of Technology, Atlanta, United States, 3Emory University, Atlanta, United States, 4Morehouse School of Medicine, Atlanta, United States, 5Boston Children's Hospital, Boston, United States
Pediatric traumatic brain injury (pTBI) outcomes are highly variable, and the Glasgow Coma Scale (GCS) provides only limited prognostic value. We examined whether applying the Comprehensive Brain Injury Model (CBI-M) in an operationalized form improves prediction of 6-month Pediatric Glasgow Outcome Scale–Extended (pGOSE) outcomes.
In a prospective cohort (N = 592), prediction models were developed in a subset of patients with 6-month pGOSE (n = 90). Unfavorable outcomes were defined as pGOSE 1–6. Twenty-eight predictors were screened with univariable logistic regression for association with unfavorable pGOSE (p<0.20), then pillar-specific multivariable models (p<0.10), leading to a combined CBI-M model. Incremental discrimination was summarized with stepwise ROC. A 5-item score was derived via ridge-penalized logistic regression with 10-fold cross-validation and internally validated with 500 Monte Carlo resamples. Discrimination is reported as AUC with 95% confidence intervals (CI).
The combined model retained GCS ≤8 (adjusted odds ratio [aOR] 9.38; 95% CI 2.38–44.1), Ubiquitin C-terminal hydrolase-L1 (UCH-L1) ≥327 pg/mL (aOR 10.5; 95% CI 1.41–21.6), midline shift on CT (aOR 10.5; 95% CI 2.36–62.1), age ≤5yr (aOR 1.27; 95% CI 0.312–4.95), and male sex (aOR 4.94; 95% CI 1.18–26.7).
Versus GCS alone, CBI-M improved AUC (95% CI) for pGOSE 7–8: 0.890 (0.805–0.954) vs 0.775 (0.682–0.869); pGOSE 3–6: 0.746 (0.614–0.870) vs 0.603 (0.476–0.730); pGOSE 1–2: 0.953 (0.903–0.992) vs 0.859 (0.806–0.912).
These findings suggest that integrating clinical, biomarkers, imaging, and patient modifiers provides superior prognostic discrimination compared with GCS alone and can be translated into a practical bedside score for pTBI.
BHB Stabilizes Circadian Fragmentation After TBI in an Alzheimer's-Vulnerable Brain
1Spinal Cord & Brain Injury Research Center, University of Kentucky, Lexington, United States, 2Department of Neuroscience, University of Kentucky, Lexington, United States, 3Sanders-Brown Center on Aging, University of Kentucky, Lexington, United States
Traumatic brain injury (TBI) and Alzheimer's disease (AD) both disrupt sleep and circadian organization, and these disturbances are linked to poor neurological recovery and cognitive decline. Because sleep deficits are clinically important and measurable, they may serve as biomarkers of treatment response. We tested whether TBI worsens sleep disruption in APP-SAA knock-in mice and whether β-hydroxybutyrate (BHB) improves this phenotype. APP-SAA KI 15-18 months old underwent closed head injury (CHI) or sham surgery and received continuous BHB or vehicle delivery using osmotic pumps implanted 3 and 16 days post-injury. Sleep was measured with Piezo Sleep and analyzed as percent change from baseline using linear mixed-effects models with time, surgery, treatment, sex, and cohort as fixed effects. CHI significantly altered sleep across the light-dark cycle. Total sleep showed a main effect of surgery (F(1,51) = 4.66, p = 0.035), light-phase sleep showed a surgery effect in the reduced model (F(1,54) = 5.63, p = 0.021), and dark-phase sleep showed main effects of surgery (F(1,51) = 4.34, p = 0.042) and sex (F(1,51) = 4.12, p = 0.048). Injury increased sleep during the dark phase, when mice should be active, indicating a shift in circadian sleep organization. BHB reduced rest-phase activity, a marker of fragmentation, in CHI females at the later post-injury timepoint (Holm-adjusted p = 0.034), consistent with partial recovery of the injury-induced sleep phenotype. These findings identify sleep fragmentation and circadian sleep disruption as features of TBI in aged AD mice and support sleep as a biomarker of therapeutic response.
Biomechanical Features of Head Impact Exposure Associated with Clinical Changes in Uninjured Contact Sport Athletes
1Medical College of Wisconsin, Milwaukee, United States, 2Zablocki Veterans Affairs Medical Center, Milwaukee, United States, 3Indiana University, Bloomington, United States
Biomechanical mechanisms for sport-related concussion include single high magnitude head impacts (i.e., concussive event) and accumulating subinjury associated with repetitive head impact exposure (HIE). While HIE was greater in concussed contact-sport athletes, HIE tolerance and biomechanical features associated with accumulating subinjury have not been defined. Twenty-one high school football athletes participated in preseason and post-season clinical assessments, along with daily head impact measurement using the Head Impact Telemetry System. Twelve athletes had clinically significant cognitive changes (RCI+) at the post-season timepoint according to reliable change index (RCI) thresholds for SAC and ImPACT assessments. Random Forest analysis with correlation-based variable reduction ranked 116 features of season-long and time-windowed single impact and HIE biomechanics in terms of their importance in differentiating between RCI+ athletes and athletes without post-season clinical changes (RCI-). The two most important features included peak linear acceleration of the season-long highest magnitude impact and the number of days between that impact and the post-season assessment. RCI+ athletes had 60% greater highest magnitude impacts (p<0.05), which occurred 28 days closer to the post-season assessment (p<0.05) compared to RCI-. The third, six, and seventh ranked features included cumulative measures of HIE (i.e., cumulative linear acceleration and risk-weighted exposure) for all impacts that exceeded 60 g’s. In all cases, RCI+ athletes had greater HIE (p<0.05). These findings indicate that high magnitude single and repeated impacts are important in accumulating clinical changes over the course of a contact-sport season and that lower magnitude impacts, despite being much more common, are not as important.
Blast-Induced Large Deformations in Brain-Like Soft Matter
Dr. Enze Chen1,
1Department of Mechanical Engineering, University of Wisconsin-Madison, Madison, United States, 2Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, United States, 3School of Engineering, Brown University, Providence, United States, 4Department of Mechanical Engineering, Iowa State University, Ames, United States, 5Department of Engineering, Robert Morris University, Moon Township, United States
Blast exposure is a major cause of traumatic brain injury (TBI) in the military population, but the underlying physical mechanisms of blast-induced TBI remain poorly understood. Although a wide range of biological pathologies have been reported, direct causation between blast loading and injurious brain deformation is difficult to establish due to the extremely short time scales of blast impulses, the inaccessibility of intracranial strain measurements, the complex geometry and material behavior of the brain, and the limited availability of facilities capable of generating controlled, open-field–like blast exposures.
In this study, we experimentally measure blast-induced deformation in skull–brain phantoms using an Advanced Blast Simulator and elucidate the governing deformation mechanisms through coupled numerical simulations. A biofidelic brain phantom embedded with a speckle pattern is subjected to well-controlled blast exposures and imaged using a dual-camera system, followed by digital image correlation (DIC) for deformation quantification.
Experimental results show that early shock–brain interaction (<2ms) produces minimal deformation, small negative pressure, and no observable cavitation under the tested conditions. However, the blast impulse induces skull rotation, resulting in large-amplitude, delayed deformation occurring tens of milliseconds after shock arrival. Matching numerical simulations are used in conjunction with the experimental measurements to reconstruct the 3D displacement and strain fields. Combined numerical and experimental results reveal how energy from the blast impulse converts into rotation of the phantom, providing a mechanistic explanation for the observed delayed deformation. Together, this work establishes a fundamental understanding of blast-induced large deformation in brain-like soft materials beyond traditional early-time-point shock metrics.
Blast-Primed CD3+ T Cells Drive Chronic Retinal Ganglion Cell Dysfunction and Loss After Adoptive Transfer
1University of Iowa, Iowa City, United States
Blast-mediated traumatic brain injury (bTBI) causes chronic retinal ganglion cell (RGC) dysfunction and degeneration. We previously showed that adoptive transfer (AT) of whole splenocytes from blast-exposed mice induces delayed RGC dysfunction and loss in naïve recipients. Here, we identified immune subsets sufficient to mediate these effects. C57BL/6J donor mice were exposed to a single 140 kPa blast or sham injury using an advanced blast simulator. Four weeks later, splenic CD3+ T cells, CD4+ T cells, CD8+ T cells, CD19+CD3− B cells, pan-B cells, dendritic cells (DCs), and NK cells were isolated and transferred into naïve recipients. Visual outcomes were assessed longitudinally by pattern electroretinography (PERG), optical coherence tomography, and BRN3A+ RGC quantification.
AT of CD3+ T cells from blast-exposed donors caused sustained PERG deficits 2 months (p=0.0002), 4 months (p=0.0005), and 6 months (p=0.041) post-AT, and reduced RGC density in the retina (p=0.001) at the termination of the study. CD4+ T cells induced a transient PERG decrease at 4 months (p=0.012) without RGC loss, while CD8+ T cells had no effect. Pan-B cells caused delayed PERG impairment 6 months following AT (p=0.005) without RGC loss. DCs induced early dysfunction (p=0.021) and reduced RGC density, whereas these effects were absent in Rag1−/− recipients (which lack mature T- and B-cells) following AT of DCs. These findings identify CD3+ T cells as key mediators of blast-induced chronic retinal neurodegeneration, with diminished roles for other immune cell types.
Blood-Brain-Barrier Signaling Biomarkers Demonstrate Distinct Temporal, Severity, and Outcome Patterns in Patients with Traumatic Brain Injury
1Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, United States
Disruption of the blood brain barrier (BBB) is a secondary injury process contributing to neurological deficit and disability after traumatic brain injury (TBI). Matrix metalloproteinase 9 (MMP-9), tissue inhibitors of metalloproteinase-1 (TIMP-1), vascular endothelial growth factor (VEGF-A) and tumor necrosis factor alpha (TNF-α) play a role in BBB permeability and their potential as injury biomarkers have yet to be elucidated. This preliminary study investigated the dynamics of MMP-9, VEGF and TIMP-1 protein levels in TBI patients, across time, injury severity (initial Glasgow Coma Scale score) and outcome measures (Glasgow Outcome Score-Extended-GOS-E). Under an approved IRB, mild (n=36), moderate (n=6) and severe (n=18) TBI subjects were enrolled, serum was acquired 1, 3, 5 days, 2- and 12-weeks post-injury and biomarkers were measured using the Meso Scale Discovery platform. Mixed effect models were used to analyze the effect of time, severity and outcome for each biomarker. There were significant effects of severity (mild, moderate, severe) for all 4 biomarkers (p<0.05). TIMP1 and VEGF-A showed a significant time effect (p=0.0096, p=0.003). GOS-E was dichotomized as favorable (severe: 5-8, mild: 7-8) or unfavorable. In severe TBI, there was a significant effect of outcome for MMP9 and TIMP1 (p=0.0008, p=0.0093). In mild TBI, there was significant outcome effect for VEGF-A and TNF-α (p=0.0137, p=0.0002). Interestingly, MMP9, TIMP1 and TNF-α levels were higher in the favorable group. These results show BBB biomarkers demonstrate a distinct biological response based on time from injury, severity, and outcome and further our understanding of secondary injury mechanisms after TBI.
Botulinum-Toxin Enhanced Expression of an Intramuscularly Injected Optogenetic AAV Vector
1Medical College of Wisconsin, Milwaukee, United States, 2Marquette University, Milwaukee, United States
Optogenetic stimulation of peripheral motor nerves has the potential to overcome several drawbacks of electrical stimulation in reanimating muscle activity paralyzed by spinal cord injury (SCI). Intramuscular injection of an adeno-associated virus (AAV) vector presents a non-invasive, clinically relevant approach to labelling peripheral nerves with light-sensitive opsins for such optical stimulation, but successful labelling of neurons relies on robust uptake of virus at the neuromuscular junction (NMJ). Previous studies have shown NMJ sprouting and remodeling after intramuscular botulinum neurotoxin (BoTX) injections, and increased uptake of an adenovirus vector. We sought to examine whether prior BoTX injection could similarly improve peripheral nerve opsin expression in rats after intramuscular AAV injection. Adult Fischer-344 rats were first injected with BoTX into the Tibialis Anterior (TA) muscle, followed by injection of an AAV6-hSyn-ChR2-eYFP optogenetic vector two weeks later. We assessed functional opsin expression weekly via transdermal optical stimulation of the targeted peroneal nerve while recording electromyography (EMG) and kinematic data. Eight weeks after virus injection, animals were perfused for histological tissue collection. Rats injected with BoTX displayed increased density and elongated morphology of NMJs in the target muscle both at the 2- and 10-week post BoTX timepoints. Rats injected with the optogenetic AAV vector after BoTX showed an earlier onset of functional opsin expression and optical sensitivity compared to control rats, as well as similar magnitudes of evoked muscle activity. These results suggest BoTX may be used to enhance AAV-mediated opsin expression for motor rehabilitation after SCI.
Brain Age and Its Association with Concussion History, Head Impact Exposure, and Clinical Measures Across Three Cohorts of American Football Players Spanning Adolescence to Early Midlife
1Department of Neurosurgery, Medical College Of Wisconsin, Milwaukee, United States, 2Department of Neurology, Medical College of Wisconsin, Milwaukee, United States, 3The Mind Research Network/Lovelace Biomedical Research Institute, Albuquerque, United States, 4Neurology Department, University of New Mexico School of Medicine, Albuquerque, United States, 5Psychiatry Department, University of New Mexico School of Medicine, Albuquerque, United States, 6Psychology Department, University of New Mexico School of Medicine, Albuquerque, United States, 7Department of Kinesiology, Michigan State University, East Lansing, United States
Brain age gap (BAG) is an emerging structural neuroimaging biomarker derived from predictive models trained on large datasets, calculated as the difference between an individual’s predicted brain age and their chronological age. Positive values indicate accelerated brain ageing, whereas negative values suggest preserved or resilient brain ageing. Prior studies have reported associations between repetitive neurotrauma with conventional structural imaging metrics and clinical function earlier in the lifespan, though its relationship with BAG remains unclear. Using T1-weighted images from 198 current and former male American football players across three cohorts spanning adolescence to early midlife (Project Head-to-Head II, n=86, Mage=18.3±1.7; ChronEx, n=57, Mage=21.1±1.5; NCAA-15, n=55, Mage=38.0±1.4), we examined associations between BAG, based on the pyment model (corrected for age and scanner differences within each cohort), self-reported concussion history, cumulative head impact exposure (CHII), depression symptom burden (PROMIS T-scores), and sleep disturbance (PSQI). BAG was not significantly associated with neurotrauma history. In the adolescent/young adult cohort (HTH2+ChronEx), BAG was not associated with clinical measures. In the early midlife cohort (NCAA-15), depressive symptoms were positively associated with BAG. One standard deviation increase in depression T-score was associated with approximately 1.9 years greater BAG (r=.31, B=0.19 [95% CI .03, .34], p=.02). Although BAG was not directly associated with concussion history or head-impact exposure, greater BAG was associated with depressive symptoms in early midlife. Given prior work linking recurrent concussion to depression, longitudinal studies are needed to clarify the contribution of BAG to the potential evolving effects of neurotrauma over the lifespan.
Brain and Spine Injuries During Rollover Crashes: Evaluating the Effects of the Updated FMVSS 216a Standard
Lauren Douglas1,2, Dr. Qi Zhang3,4, Dr. Thomas Jenkyn1,2,
1Mechanical and Materials Engineering, Western University, London, Canada, 2Biomedical Engineering, Western University, London, Canada, 3Department of Pathology and Laboratory Medicine, London Health Science Centre, Western University, London, Canada, 4Department of Clinical Neurological Sciences, London Health Science Centre, Western University, London, Canada
Despite accounting for less than 5% of total crashes, rollovers account for approximately 30% of annual fatalities. Beyond fatalities, severe brain and spine injuries remain a major concern. The Federal Motor Vehicle Safety Standard (FMVSS) 216a was updated in 2009 and enacted in 2016 vehicle models. It mandates vehicle roofs undergo a weighted plate of 3x the vehicles weight (increased from the previous 1.5x) without crushing the roof more than 5” or applying greater than 50lbs of force to a 50th percentile male head form.
This study aimed to determine the effects of the FMVSS 216a update on real-world crashes. The National Highway Traffic Safety Administration’s Crash Investigation Sampling System database was used and was filtered to include vehicles with model years between 2010-2012 (pre-update) and 2016-2018 (post-update). The phase-in period including 2013-2015 vehicle years was excluded. The database yielded 56 rollovers with 63 severely injured occupants in the 2010-2012 group, and 87 rollovers with 95 severely injury occupants in the 2016-2018 group.
57% of rollovers in the 2010-2012 cohort had roof crush, and 59% had head and spine injuries. The most common being cerebrum subarachnoid hemorrhages (24%) and cerebrum hematomas (22%). 44% of rollovers in the 2016-2018 cohort had roof crush, and 45% had head and spine injuries. The most common being cerebrum hematomas (18%) and basilar skull fractures (17%). Given the only 13% decrease in roof crush occurrence and 14% decrease in head and spine injuries, this analysis supports further investigation into the biomechanics of rollover crashes.
Brain Injury & Inflammatory Biomarker Trajectory Variations in Surgical Approaches
1University Of Pittsburgh, Pittsburgh, United States, 2NYU Grossman School of Medicine, New York, United States
Blood biomarkers have increased utilization in prognosticating outcomes following traumatic brain injury (TBI). The endoscopic endonasal approach (EEA) to skull base tumors is a less tissue disruptive approach compared to open craniotomy (OPEN), potentially decreasing trauma associated with surgical interventions performed after disease or injury. This study conducted a time-course of injury biomarkers in serum to compare biomarker levels after OPEN or EEA surgeries. Patients undergoing tumor dissection (N=40) were enrolled into two surgery groups, EEA (N=21) or OPEN (N=19). Serum was collected up to five times within a two-week period (pre-operative, days 1-2 post-surgery, follow-ups). Neurofilament light chain (NfL) and pro-inflammatory biomarkers were measured using the MesoScale Discovery platform. Statistical analyses were completed using log-transformed biomarker concentrations on a mixed-effects model (fixed-effects for time, surgery, and their interaction with subject-level random intercepts). Analysis showed significant time interactions for NfL, interleukin (IL)-6, IL-10, IL-4, tumor necrosis factor (TNF)-α and interferon (IFN)-γ (p<0.001). Significant surgery interaction was observed in IFN-γ (p=0.003) noting a higher average concentration in the OPEN surgery group. Significant interactions were observed in NfL and IL-6 between surgery groups (p=0.009, p=0.001), with NfL levels higher at follow-up (EEAm=1.48pg/mL, OPENm=32.13pg/mL) and IL-6 levels higher at day 2 post-surgery (EEAm=1.78pg/mL, OPENm=5.56pg/mL). Other inflammatory markers showed no significance by time, surgery type, or interaction (IL-12p70, IL-13, IL-1β, IL-2, IL-8). This pilot investigation demonstrates an increase in various biomarkers following craniotomy vs EEA surgical approach, which may be due to a reduced inflammatory response from a less traumatic operative corridor.
Brain Injury Blood Biomarker Levels Remain Consistent Across Collection and Processing Variations in Healthy Controls
1University Of Pittsburgh, Department of Neurosurgery, Pittsburgh, United States, 2University of Pennsylvania, Philadelphia, USA, 3Foundation for Applied Molecular Evolution, Alachua, USA, 4University of British Columbia, Vancouver, Canada, 5Children's Hospital of Eastern Ontario, Ontario, Canada, 6University of Messina, Messina, Italy
Blood based biomarkers are emerging as a critical diagnostic and prognostic tool across the spectrum of traumatic brain injury. However, consistent protocols for the collection and processing of blood samples for analysis are lacking. Understanding factors that may potentially alter accurate measurement of blood protein is crucial to advancement of the use of injury biomarkers in the clinical space. The aim of this study was to determine the effect of varied blood collection and processing of hallmark injury biomarkers in blood. This study enrolled healthy participants (N=12) to undergo fasting and non-fasting blood draws. Participants fasted for 8-12 hours before the first blood draw (fasting), then received a second blood draw 30 minutes after consuming a 360-calorie BOOST protein shake (non-fasting). Blood samples were centrifuged at either 1,500 RCF or 2,800 RCF. Plasma and serum samples were analyzed for brain derived (BD)-tau, glial fibrillary acidic protein (GFAP), neurofilament light (NFL), and ubiquitin carboxy-terminal hydrolase LI (UCH-L1) using the Quanterix platform. Wilcoxon Signed Rank test was used to assess changes in protein concentration. No significant results were found in centrifuge speed or fasting status (p>0.05); however, trends were observed in the comparison of fasting groups in plasma BD-tau (p=0.052) and centrifugation speed in plasma GFAP (p=0.052). This data suggests that protocol standardization is vital for the future use of blood biomarkers in the TBI field. Future analyses will explore additional collection and processing variations to support the harmonization of collection and processing methods across studies.
Building Partnerships to Optimize Traumatic Brain Injury Care: A Community-Based Participatory Research (CBPR) Approach to Health System Improvement
1Medical College of Wisconsin - Milwaukee, WI, Milwaukee, United States, 2Brain Care Catalyst Foundation, Patient stakeholder, MILWAUKEE, United States, 3The Ohio State University, Columbus OH, Columbus, United States, 4University of Kentucky, Lexington, KY, Lexington, United States
Meaningfully engaging community partners is increasingly expected by funders and essential to effective health system improvement research. However, community engagement has not historically been embedded in TBI research, and it is unclear how to carry out effective engagement. As part of our federally-funded implementation science study (EDucate)—which aimed to improve concussion education in emergency departments—we implemented a community-based participatory research (CBPR) plan. We retrospectively mapped our partnership processes onto the Patient-Centered Outcomes Research Institute (PCORI) Six Foundational Expectations for Partnerships to illustrate how our CBPR approach aligns with established engagement principles. Our CBPR process demonstrated strong representative involvement of relevant stakeholders, meaningful inclusion/ongoing engagement of partners in decision making, and ongoing review and assessment of engagement. Stakeholder engagement highlighted opportunities to strengthen discharge communication, improve clinical workflow, and standardize patient education. We identified opportunities to improve partnerships by tailoring and strengthening partner recruitment to accommodate attrition and allow fluctuations in engagement. We also uncovered gaps in communication with select stakeholder groups, necessitating better long-term engagement plans. In a Year 2 partnership survey, partners were satisfied with the project goals (82%), collaborative environment (73%), and personal skill development (82%). Applying CBPR principles within our health system strengthened the relevance, and uptake of TBI education. This project provides generalizable lessons/recommendations for others seeking to develop more genuine engagement with diverse community members in their research, and demonstrates how collaborative, community-engaged methods can enhance quality improvement efforts, support patient-centered care, and improve outcomes for populations with complex needs.
C3 and CD14 Are Structure-Specific Regulators of Acute Microglial Neuroinflammation in a Murine TBI+polytrauma Model
1Ulm University, Ulm, Germany
Traumatic brain injury (TBI) associated with non-cerebral injuries defines the TBI-polytrauma (TBI-PT) associated with acute neurological deterioration, delirium and severe prognosis, due to the systemic inflammation enhancing the focal neuroimmune reaction with detrimental consequences. Microglia is anticipated to respond to local as well as systemic damage-associated molecular patterns (DAMPs) in TBI-PT. We explored the role of Complement factor 3 (C3) and of the TLR-co receptor CD14 in a murine polytrauma model including mild TBI, femur fracture, thorax blunt trauma and resuscitated haemorrhagic shock, making use of WT, C3-/-, CD14-/- or C3-/-/CD14-/- mice. TBI-PT resulted in rapid (3h), brain-wide induction of cytokines, with TNF and Il1b dominating in striatum vs TNF and CCL-2 in cortex. TNF and CCL2 mRNA ands protein synthesis rate was upregulated in microglia upon TBI-PT in cortex, striatum and hippocampus but not in C3-/-CD14-/- animals. The induction of TNF and CCL2 was abolished in C3-/- but not in CD14-/- animals in striatum and cortex controlateral to the lesion but were suppressed in the hippocampus of either genotype. In the cortical focal lesion neither C3 nor CD14 affected the induction of pro-inflammatory cytokines. C3 and CD14 are dispensable for the acute cytokine response to TBI-PT in the site of cerebral injury but are differentially necessary across cortex, hippocampus and striatum for their induction in the microglia of the non-injured parenchyma. Interventions on C3 may reduce the encephalopathy risk associated with TBI-PT but not the acute response in the injury site, where other DAMPs may offer redundant activation pathways.
Cannabigerol in Traumatic Brain Injury: Acute Behavioral Findings Inform Future Delivery Strategies
Dr. Jena' Mazique1, Dr. Robert Welch2, Blake Smith3,
1University of Mississippi Medical Center, Jackson, United States, 2University of Mississippi, Oxford, United States, 3Intrepid Biosciences & Zion Pharmaceuticals, Murray, United States
Traumatic brain injury (TBI) precipitates a complex cascade of secondary injury processes—neuroinflammation, oxidative stress, axonal degeneration, synaptic disruption, and anxiety-like behavioral disturbances—that extend well beyond the initial mechanical insult. Collectively, these mechanisms exacerbate tissue damage and underlie the persistent functional impairments observed after injury. Cannabigerol (CBG), a non-psychoactive phytocannabinoid, engages CB2 receptors on myeloid-lineage immune cells and microglia and acts as an agonist at peroxisome proliferator-activated receptor gamma (PPARγ) in macrophages, thereby attenuating NF-κB–mediated inflammatory signaling.
Using the Closed-Head Impact Model of Engineered Rotational Acceleration (CHIMERA) in male rats, we examined the acute behavioral sequelae of TBI and assessed whether post-injury CBG administration (10 mg/kg, intraperitoneally, once daily for two days) modulated behavioral outcomes or peripheral immune profiles. Behavioral testing conducted approximately three hours post-injury demonstrated that TBI animals—regardless of treatment—exhibited pronounced light-arm avoidance and start-arm preference relative to sham controls, consistent with post-traumatic photosensitivity and diminished exploratory drive. CBG did not ameliorate these behavioral deficits and was additionally associated with reduced overall locomotion compared to sham, whereas vehicle-treated TBI animals did not show a statistically significant reduction on this measure.
These findings suggest that intraperitoneal delivery may limit CBG bioavailability in this context. Accordingly, future studies will prioritize the evaluation of orally bioavailable formulations to more effectively interrogate its therapeutic potential.
Caveolin-1 Scaffolding Domain Peptide Improves Mild Traumatic Brain Injury (mTBI) Outcomes in a Juvenile Mouse Model
1Department of Neuroscience, University of California, Riverside, Riverside, United States, 2Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, United States, 3Centre d’Études Biologiques de Chizé, CNRS-UMR7372, La Rochelle Université, Villiers-en-bois, France, 4Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, United States
Objectives: Endothelial caveolin-1 (Cav-1) participates in blood-brain barrier integrity, angiogenesis, and neurovascular coupling. Caveolin scaffolding domain (CSD) anchors cell signaling molecules, and is mimicked by a synthetic peptide associated with antennapedia, Cav-AP. This study evaluated the efficacy of Cav-AP in improving outcomes following mild closed head injury (CHI) in juvenile mice.
Methods: Postnatal day 17 (PND17) C57BL/6 mice were assigned to four experimental groups: sham scrAP, sham Cav-AP, CHI scrAP, CHI Cav-AP (scr-scrambled). Behavioral assessments, including open field, were performed at 1 and 30-day post-injury (dpi). Functional ultrasound imaging (fUSI) was performed to assess vascular function and morphology. The cerebral vasculature was painted by intracardiac DiI injection at 1 or 30dpi.
Results: At 1dpi, neither scrAP nor Cav-AP treatment significantly altered anxiety or motor mobility levels in any of the groups. Cav-AP-treated sham or CHI mice exhibited increased distance travelled in the open field compared to scrAP treatment. Cav-AP increased vessel density, vessel length, and junction density in both CHI and sham animals at 1dpi. At 30dpi, fUSI revealed that CHI Cav-AP mice had enhanced cerebral vascular coupling compared to CHI scrAP.
Conclusions: Cav-AP induced both morphological and functional vascular alterations in both sham and CHI animals at 1dpi. Increased neurovascular coupling was observed in CHI Cav-AP mice compared to CHI scrAP mice, a potential mechanism for the observed behavioral changes. This improvement in cerebral vascular outcomes suggests that Cav-AP may represent a potential pharmacological treatment for juvenile mTBI.
Cellular Prion Protein Deletion Affects Gene Expression and is Neuroprotective in a Repetitive Head Injury Model
1Morehouse School of Medicine, Stone Mountain, United States, 2Department of Neurosurgery, Emory University School of Medicine, Atlanta, United States, 3Department of Neuroscience, Yale School of Medicine, New Haven, United States
Introduction: Cellular prion protein (PrPc) is the neuronal receptor for Amyloid beta oligomers. We have shown that PrPc is essential for development of neurologic deficit after traumatic brain injury (TBI). However, the molecular pathways mediating PrPc TBI related deficits are unknown. We performed mRNA expression analysis in mouse cortex using a repetitive head injury (rHI) model in PrPc knockout (KO) mice and controls to evaluate behavioral and transcriptional changes seven weeks after rHI.
Methods: Three-month-old mice were used in four groups, WT and PrPc KO with and without rHI. Cognitive performance was assessed using acquisition and probe trials of Morris Water Maze (MWM). Mice were sacrificed, and bulk RNA sequencing was performed on injured and uninjured cortex. Differentially expressed genes (DEG’s) were identified by the institutional core facility.
Results: Injured PrPc KO mice performed comparably to uninjured controls in MWM testing suggesting a neuroprotective effect. DEG analysis demonstrated significant transcriptional differences between WT impacted cortex and PrPc KO impacted cortex. Of 209 upregulated DEG’s in WT impacted animals, 27 (12.9%) showed reversal in PrPc KO injured mice. Of 29 downregulated DEG’s, 31% demonstrated reversal in PrPc KO mice. Notable DEG’s included Orexin, FERMT1, and C3.
Conclusion: PrPc deletion modulates neurobehavioral and transcriptional outcomes following TBI. mRNA expression analysis showed multiple DEG’s involved in inflammation, wakefulness, and arousal. Further studies are needed to clarify the mechanism by which PrPc deletion affords neuroprotection in head injury.
Cellular Responses After Combined Treatment for Repetitive Low-Level Blast-Induced Traumatic Brain Injuries
1Laboratory of Molecular Biology, VA New Jersey Health Care System, East Orange, United States, 2Neurobehavioral Research Laboratory, VA New Jersey Health Care System, East Orange, United States, 3Laboratory for Regenerative Neurobiology, Rutgers-New Jersey Medical School, Newark, United States, 4School of Graduate Studies, Rutgers University, Newark, United States, 5Dept. of Pharmacology, Physiology, & Neuroscience, Rutgers-New Jeresy Medical School, Newark, United States, 6Department of Neuroscience, Mayo Clinic, Jacksonville, United States, 7Biomedical Engineering and Center for Injury Biomechanics, Materials and Medicine, New Jersey Institute of Technology, Newark, United States
Repetitive low-level blast-induced TBIs are too common and significant numbers of military personnel have been affected. As detailed in many news reports and recognized by policymakers, a typical case would involve a Veteran who previously sustained blast exposures, e.g., from mortar firings while serving in an artillery unit, and now has significant difficulties with daily activities and the ability to remember tasks required for work. We have been investigating factors that could be targeted therapeutically to improve outcomes. Our mouse model mimics the effects of pressure wave exposures produced by heavy-caliber and breaching weapons. Mice received five 70 kPa (12 PSI) peak overpressure blasts with one-minute intervals. We tested a combined treatment of positive modulators of transcription factors, Nrf2 and PPAR-γ, administered 30 minutes after injury. We examined cell-specific mRNA dysregulations in acute response to the low-level blasts and the treatments with snRNA-seq at 24 hours after injury. We have been analyzing the specific genes, processes, and pathways that were altered. For example, in neurons of the dentate gyrus, genes involved in neuron projection organization were downregulated (-2.2 normalized enrichment score) by the low-level pressure waves while neuron projection morphogenesis genes were upregulated (2.7 NES) by the treatment with adjusted p-values < 10-6. We hope that a better understanding of mechanistic responses to the low-level blasts and the treatment through the regulatory factors will help identify useful treatment strategies that could improve the health of Veterans with exposure histories.
Supported by the VA, DOD, and Veterans Bio-Medical Research Institute.
Cerebellar Gray Matter Volume and Associated Outcomes in Balance in Athletes with Repetitive Head Impact
1Georgia State University, Department of Psychology, Atlanta, United States, 2University of Utah, Department of Psychology, Department of Neurology, Salt Lake City, United States
Repetitive head impacts (RHI), including concussion and asymptomatic impacts, can impair balance and alter brain tissue, particularly in older age. However, whether RHI disrupts cerebellum structure is unknown. This study examined the effects of RHI and age on cerebellar gray matter volume and whether volume relates to balance in athletes with and without RHI exposure.
Seventy athletes (43 RHI/27 comparisons; ages 18–42; 80.0% Male; 38.6% White) were recruited for the Atlanta Fighter Study and completed 3T MRI. The RHI group included active combat sport athletes. Comparisons were age- and sex-matched noncontact sport athletes without RHI histories. Automated segmentation of T1-weighted images computed volume for 21 cerebellar regions. The modified Balance Error Scoring System total errors score was used to measure balance. Linear and Poisson regressions, with multiple comparison correction, were conducted.
Groups did not differ in demographics or balance scores. Age moderated group differences for vermis Crus II volume (adjusted p <.01). In older athletes (95th percentile, 39.9 years), relative to comparisons volume was substantially higher after RHI (d = 1.38, p <.05). Age and vermis Crus II volume moderated group differences in balance scores (p <.01). At older age and higher volume, balance error scores were substantially higher after RHI versus comparisons (Incidence Ratio Rate = 7.16, p <.001).
Results suggests that RHI exposure may be associated with neuroinflammatory changes that alter cerebellar structure, leading to functional consequences later in life. Results highlight the need for additional research on the effects of RHI on the cerebellum.
Cerebral Perfusion, Oxygenation, and Metabolism During Progressive Intracranial Pressure Elevation in Piglets
Sule Karagulleoglu-Kunduraci1,3,
1Western University, London, Canada, 2Lawson Research Institute, London, Canada, 3Robarts Research Institute, London, Canada
Intracranial hypertension contributes to secondary brain injury by reducing cerebral perfusion pressure (CPP) and impairing cerebral blood flow and oxygen delivery. However, detecting the physiological effects of rising intracranial pressure (ICP) typically requires invasive monitoring, limiting its use in neonatal populations. We investigated whether diffuse optical monitoring could characterize cerebral hemodynamic and metabolic responses to progressive ICP elevation.
Seven newborn piglets were monitored with a hybrid system combining broadband near-infrared spectroscopy (bNIRS) and diffuse correlation spectroscopy (DCS). DCS provided an index of cerebral blood flow (CBFi), while bNIRS measured tissue oxygen saturation (StO2) and the oxidation state of cytochrome-c-oxidase (oxCCO), a marker of metabolism. ICP was gradually increased via ventricular saline infusion while mean arterial pressure and ICP were recorded to compute CPP.
CBFi deviated significantly from baseline when ΔCPP dropped below −11 mmHg, while StO2 deviated when ΔCPP fell below −15 mmHg. In contrast, oxCCO remained unchanged across ΔCPP levels, suggesting preserved cerebral energy metabolism despite elevated ICP. Breakpoint analysis revealed transitions to steeper declines as CPP decreased: StO2 showed the earliest breakpoint (−7.5 mmHg), followed by CBFi (−10.5 mmHg), while oxCCO changed only at substantially lower CPP (−17.5 mmHg). The delayed oxCCO breakpoint is consistent with compensatory increases in oxygen extraction preceding metabolic compromise.
Multimodal optical monitoring revealed a physiological sequence during ICP elevations: early perfusion decline, altered oxygenation, and delayed metabolic disturbance. Non-invasive optical monitoring may therefore help detect hemodynamic stress associated with rising ICP and enable earlier identification of impending cerebral compromise across neurocritical care populations.
Characterizing Persistent Neurotological Deficits Following Blast Exposure
1University Of Miami, Coral Gables, Florida, United States
Primary blast injury can result in significant auditory and vestibular dysfunction, imbalance, and cognitive impairment. Since the underlying pathophysiology remains incompletely understood, this study investigated damage to the inner ear and associated central nervous system pathways by characterizing the long-term functional, behavioral, and histological consequences following blast exposure. Controlled overpressure exposures of 10–12 psi were generated using a customized blast apparatus. Auditory and vestibular function were evaluated using auditory brainstem responses (ABR) and cervical vestibular evoked myogenic potentials (cVEMP), respectively. Behavioral outcomes were assessed using balance beam testing and quantitative gait analysis. Performance was measured by time to cross, number of stops, and foot falls as indicators of balance and motor coordination. Locomotor changes were further quantified using machine-learning–assisted body-part tracking to extract kinematic parameters such as step length, step with and cadence. In addition, histological analyses of the inner ear and relevant brain regions were performed to assess structural damage. Results showed that a single blast exposure produced persistent ABR and cVEMP threshold shifts for up to one-year. In contrast, balance beam deficits gradually subsided by approximately seven months after blast exposure, suggesting possible central compensation. Histological analysis revealed significant inner and outer cochlear hair cell loss at one-year post-blast, along with vestibular hair cell degeneration. Together, these findings demonstrate persistent peripheral sensory injury following blast exposure and highlight the importance of integrating functional, behavioral, and histological assessments to better understand the mechanisms of blast-induced neurotological damage.
Characterizing the Immune Response in SCI Treated with FPLG
1Rush University, Chicago, United States
Spinal cord injury (SCI) is characterized by a primary mechanical injury followed by a secondary injury cascade involving inflammation, oxidative stress, and apoptosis. Secondary damage is largely driven by overactivation of the immune system. Research into the immune profile following SCI has revealed a complex and dynamic interplay between innate and adaptive immune responses that contribute to both neurodegeneration and repair. After injury, there is an acute infiltration of neutrophils and macrophages, leading to the release of pro-inflammatory cytokines exacerbating tissue damage. In rodent models, macrophage activity peaks at 7- and 60-days post-injury (dpi), influencing inflammation, and repair. Scaffolds made from poly(lactic-co-glycolic) acid (PLG), a bioresorbable polymer, have emerged as a promising strategy for promoting regeneration and modulating inflammation. This study explores the effects of a highly porous form of PLG, Fluffy PLG (FPLG), at various timepoints after injury to assess its effects.
Female wild-type Sprague Dawley rats underwent a bilateral moderate contusion at the ninth thoracic vertebral level (T9) or a laminectomy at the same level. At 1 dpi, a subset of rats underwent a myelotomy at the site of injury, or implantation of FPLG. At 2-, 5-, and 7- dpi all rats were sacrificed for flow cytometric analysis and immunohistochemistry. FPLG scaffolds appear to sequester inflammatory macrophages, preserve spinal cord structure, and induce a sub-acute anti-inflammatory shift at 7 dpi, highlighting FPLG's potential to modulate inflammation and support tissue preservation in SCI.
Characterizing the Role of Nursing Staff in the Implementation of a Remote Monitoring Tool for Adults Acutely Recovering from Concussion
1Medical College of Wisconsin, Wauwatosa, United States, 2Froedtert Health, Wauwatosa, United States
Background: Patients’ desire for individualized support during concussion recovery inspired the
Concussion GetWell Loop (GWL) – a remote monitoring tool providing education, symptom monitoring, and access to concussion specialists for 30 days. This program enables patients to connect with the Concussion Nurse for personalized support, care, and education.
Aim: Characterize the role and function of the Concussion Nurse to guide other centers developing post-acute pathways of concussion care.
Methods: 355 adults recovering from concussion were invited to the program and contacted by the Concussion Nurse from August 1st, 2024, thru October 30th, 2025. We coded all nurse encounters for content and outcomes. Data were collected via GWL exports and electronic medical records. All data were analyzed in IBM-SPSS Statistics.
Results: The Concussion Nurse contacted 355 patients 529 times (median [IQR] = 1 [1, 2]). 333 (62.9%) of the contacts were intended to follow-up on concussion recovery after discharge, 80 (15.1%) for alerts of concerning symptoms, and 50 (9.45%) for individualized patient circumstances, most notably care coordination and referrals (24 contacts, 48.0% of non-standard contacts). 227 (52.4%) contacts resulted in a patient response. 207 contacts (39.1%) resulted in the Concussion nurse providing additional concussion recovery education to the patient. When education was provided, 135 (65.2%) received an official Center for Disease Control hand-out with general information and 87 (42.0%) received education specific to their symptom burden.
Discussion: The Concussion Nurse serves a unique and valuable role in the remote monitoring tool by individualizing the care and education patients receive.
Chronic Microvascular Disruption Is Associated with Traumatic Brain Injury
1University Of Washington Department Of Neurology, Seattle, United States, 2University of Washington Department of Neuropathology, Seattle, United States
Traumatic brain injury (TBI) leads to elevated risk for diseases associated with vascular dysfunction, including stroke and neurodegenerative disease, decades after the initial injury. It is well known that TBI acutely disrupts the cerebral vasculature. However, whether vessels are restored to pre-injury function or remain indelibly impaired and contribute to incident neurological disease remains largely unknown. Here, using human post-mortem brain tissue, we assessed whether patients with chronic TBI have altered cerebral microvasculature. Brain donors under the age of 65 with chronic brain contusion in the orbitofrontal cortex (OFC) and age-matched controls without a history of head injury were chosen for evaluation. In the OFC sections stained with hematoxylin and eosin, cerebral microvascular area (capillary area normalized to tissue area) as well as capillary number and size were quantified in three regions (cortex, u-fibers, white matter). Chronic TBI cases demonstrated decreased microvascular area in the cortex (p = 0.019) and u-fiber (p = 0.023) regions as well as fewer numbers of capillaries in the u-fiber region (0.009) compared to controls. These results support chronic alterations in microvasculature, especially in the grey matter and grey-white junction, after TBI. Further investigation into function of the neurovascular unit of these vessels is warranted to understand the implications on neuronal function.
Chronic Myoclonic Seizure Burden Following Repetitive Blast Exposure and Social Isolation
1University of Kentucky, Lexington, United States
Introduction: Blast-induced traumatic brain injury (bTBI) is a prevalent injury among military personnel and is associated with an increased risk of post-traumatic epilepsy (PTE). Although clinical evidence increasingly implicates epileptogenesis in bTBI, the underlying mechanisms remain largely unexplored. This study aims to develop a preclinical model of repetitive bTBI (rbTBI) and investigate long-term seizure burden and sleep–wake alterations under conditions of social isolation.
Methods: Adult male and female Sprague–Dawley rats (rbTBI: males n=15, females n=15; sham: males n=7, females n=5) received sham procedures or two blast exposures 24 h apart using a helium-driven shock tube (19.69 ± 1.15 psi; impulse: 57.49 ± 2.00 psi·ms). After a 4-month latency under single housing, animals were monitored for one month in noninvasive piezoelectric cages (Signal Solutions LLC) to assess seizures (SeizureStats) and sleep (SleepStats). Following, whole brain GFAP protein expression was quantified.
Results: No differences in total sleep time were observed between rbTBI and sham groups, however rbTBI animals showed reduced light-phase sleep (p=0.013) and increased dark-phase sleep (p=0.0164) between weeks 17 and 20 post-rbTBI. Sleep percentage was higher in males than females in both groups. Myoclonic events occurred in 93% (14/15) of rbTBI males versus 67% (10/15) of rbTBI females, with 82% of total events occurring during the dark phase. rbTBI males also showed significantly higher GFAP expression than rbTBI females, consistent with greater myoclonic activity.
Conclusions: These findings suggest that rbTBI exacerbates myoclonus in socially-isolated animals and that the emergence of myoclonic events occurs independently of overt sleep disturbances.
Chronic Pain Following Mild Concussive-like Injury: Development of a Rat Model
Mr. Eric J. Sánchez Ayala1
1University Of Puerto Rico at Cayey, Caguas, Puerto Rico
Chronic pain, one of the most common outcomes of mild traumatic brain injury (mTBI), affects over 60% of patients. Nonetheless, the underlying mechanisms remain poorly understood due to the lack of reliable animal models. A repetitive closed head injury (rCHI) weight-drop approach was used to develop a rat model of mTBI-induced chronic pain. Injury severity was evaluated through time to wake, right, and ambulate, and no significant differences were observed between groups, supporting the mild injury criteria. Locomotor activity, assessed by distance traveled in the open field at various time points after injury, was not affected in our model. Von Frey filaments were used to assess pain-related behaviors via cephalic and extra-cephalic mechanical sensitivity. rCHI animals displayed cephalic (p=0.002) and hindpaw (p=0.0380) mechanical allodynia up to 49 days post-injury. Anxiety index, assessed with the elevated plus maze, was not a comorbidity in this model (p=0.8673). Microglial (Iba-1) and neuronal activity (cFos) markers were analyzed in pain-processing regions such as the anterior cingulate cortex (ACC) and periaqueductal gray (PAG). No significant changes were observed between groups in microglia in the ACC (p=0.8150) or PAG (p=0.4166), nor in neuronal activity in the ACC (p=0.4166) or PAG (p=0.3835). Future work will focus on analyzing glial morphology, astrocytes (GFAP), neuronal density (NeuN), neurofilament (Nf-1), and proinflammatory cytokine expression in serum and brain tissue. In summary, we developed a model that shows human-like persistent pain and may help elucidate mechanisms of pathological pain following mTBI, contributing to the development of targeted therapies.
Clinical Trial of Inhaled Nitric Oxide for Treatment of Microvascular Dysfunction in Acute Traumatic Brain Injury: Preliminary Report
1University of Pennsylvania, Philadelphia, Pennsylvania, United States
Background/Objective: Microvacular ischemia is a major secondary phenomena following traumatic brain injury (TBI). Inhaled nitric oxide (iNO) is currently FDA approved for hypoxic respiratory failure in neonates. This study was initiated to explore the potential for optimizing cerebral perfusion after acute TBI. Methods: Five initial patients with GCS 9-12 or GCS 13-15 with abnormal imaging are reported (target enrollment: 38). Subjects with TBI (within 72 hours) were enrolled and randomized into standard respiratory support (SRS) or iNO group (open-label). Each group received SRS or iNO each day lasting 1-4 hours, up to 4 days. Direct correlation spectroscopy (DCS) and near infrared spectroscopy (NIRS) were used to monitor relative blood flow and oxygen saturation. This was analyzed using linear mixed effect model. We monitored for methemoglobin levels, hypotension, headaches, creatinine levels, and neurological exam changes. Results: NIRS showed increased relative oxygen saturation in iNO vs SRS group: 0.033 [0.024,0.041] vs 0.018 [0.011,0.025] %/min, P=0.0097 and DCS showed trend toward increased perfusion in iNO vs SRS group 0.43 [0.33,0.54] vs 0.31 [0.23,0.40] %/min, P=0.0903. No episode of hypotension was noted for either groups throughout the study. Methemoglobin, Creatinine levels, and rates of headache showed no difference between the SRS and iNO groups. Key TBI injury blood biomarkers and 6-month outcome results are pending further study progress. Conclusion: This is a preliminary data set for the ongoing iNO clinical trial (n=5), showing promising results for iNO optimizing cerebral blood flow after acute TBI.
Closed-Head Diffuse Traumatic Brain Injury Alters the Gut Microbiome in Female Pigs
1Center for Brain Injury & Repair, Department of Neurosurgery, University of Pennsylvania, Philadelphia, United States, 2Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, United States, 3Department of Bioengineering, University of Pennsylvania, Philadelphia, United States
Approximately 2.5 million Americans experience a traumatic brain injury (TBI) annually, contributing to approximately 5.3 million people living with TBI-related disabilities nationwide. Beyond the initial mechanical insult, TBI triggers systemic changes, including gut microbiome dysbiosis. Here, we investigated the relationship between the injured brain and microbiome in a clinically relevant closed-head diffuse TBI model, emulating the most common presentation of TBI in humans. Female pigs underwent a sham, low-velocity (85–95 rad/s), or high-velocity (105–110 rad/s) TBI in the sagittal plane. This procedure generated no notable pathology in sham brains while fibrinogen staining was extensive 3 days after a high-velocity TBI in midline brain regions but was minimal 14-days post injury (dpi) following high- and low-velocity TBIs. Stool samples were collected pre-injury and 1-, 3-, 7-, 10-, and 14-dpi. Shotgun metagenomics revealed reductions in two major short-chain fatty acid (SCFA)-producing phyla, Firmicutes and Bacteroidetes, following TBI relative to sham, and at 1- and 14-dpi relative to pre-injury. SCFA-producing genera, Roseburia, Butyrivibrio, Pseudobutyrivibrio, Anaerobutyricum, and Anaerostipes, were significantly decreased following TBI. Similarly, SCFA-producing species (Roseburia hominis, Blautia sp. SC05B48, and Megasphaera elsdenii) and beneficial Lactobacillus species (L. salivarius, L. reuteri) were reduced post-TBI. Finally, genes involved in butyrate synthesis, a SCFA, were decreased following TBI. Together, these data suggest that TBI induces broad disruption of SCFA-producing taxa. SCFAs are immunoregulatory, neuroprotective, and essential for metabolic homeostasis, and their loss could negatively influence brain and systemic health. These findings suggest potential microbial targets for therapeutic intervention to enhance recovery after TBI.
Cluster Analysis of TBI Serum Biomarker Trajectories Identifies Critical Care Subgroups Predicting Global Outcome and Quality of Life
Thanh Son Do1, Chantal Carnes2, Dr. Firas Kobeissy3, Guangzheng Cai3,4, Dr. Gayla R. Olbricht6, Dr. Ewout W. Steyerberg5, Dr. Andras Buki7, Dr. David Menon8, Dr. Andrew Maas9,10, Dr. Kevin K. Wang3,4,
1Missouri State University, Springfield, United States, 2Department of Surgery, Meharry Medical College, Nashville, USA, 3Department of Neurobiology, Center for Neurotrauma, Multiomics & Biomarkers, the Neuroscience Institute, Morehouse School of Medicine, Atlanta, USA, 4Foundation for Applied Molecular Evolution (FfAME), Alahua, 32615, 5Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, The Netherlands, 6Mathematics & Statistics Department, Missouri University of Science & Technology, Rolla, USA, 7Department of Neurosurgery, Örebro University, Sweden, 8Department of Medicine, University of Cambridge, United Kingdom, 9Department of Neurosurgery, Antwerp University Hospital, Belgium, 10Department of Translational Neuroscience, Faculty of Medicine and Health Science, University of Antwerp, Belgium
Traumatic brain injury (TBI) is highly heterogeneous, and current prognostic tools often rely on single time-point clinical or biomarker measurements that may not capture dynamic evolution of injury processes. This study aimed to identify temporal serum biomarker trajectory profiles in ICU patients with CT-positive TBI and evaluate associations with long-term functional outcome, mortality, and quality of life.
We analyzed 373 patients from the multicenter CENTER-TBI study who had ≥2 serum samples collected within first 5 days post-injury. Unsupervised machine-learning (clustering) was applied to identify trajectory classes using six brain injury biomarkers—GFAP, UCH-L1, NfL, Tau, S100B, and NSE. Associations between trajectory membership and clinical outcomes were assessed using Glasgow Outcome Scale Extended (GOSE), mortality, and Quality of Life after Brain Injury Overall Scale at 3, 6, and 12 months. Incremental prognostic value beyond the IMPACT prediction model was also evaluated.
Two distinct trajectory classes (high and low) emerged for all biomarkers. Patients with high biomarker trajectories showed increased odds of poor functional outcome (GOSE:1–4; OR 8.79–12.29, P<0.001) and higher 6-month mortality (OR 14.84, P<0.001). Low-trajectory profiles predicted favorable recovery (GOSE:6–8; OR 7.42–10.83) and improved quality of life (QoLIBRI-OS≥52; OR 4.98). Trajectory-based models demonstrated stronger predictive performance than single day-1 biomarker measurements and provided additional prognostic value when integrated with IMPACT model (ΔR2 up to 17%).
These findings highlight clinical relevance of longitudinal biomarker monitoring in neurotrauma care. Early biomarker trajectory profiling may improve risk stratification, guide ICU management, and support precision patient selection for clinical trials targeting secondary injury processes post-TBI.
CNS-Injury Proteins, Repetitive Head Impact Exposure, and Prior Concussion in Collegiate Athletes 5-10 Years Post-Career: A CARE Consortium Preliminary Analysis
1Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, United States, 2Department of Physical Medicine & Rehabilitation, Uniformed Services University of the Health Sciences, Bethesda, United States, 3Michigan Concussion Center, University of Michigan, Ann Arbor, United States, 4Department of Psychiatry, Indiana University School of Medicine, Indianapolis, United States
Early biomarkers of pathological processes that may place subsets of athletes with repeated concussion and exposure to repetitive head impact (RHI) at risk for adverse long-term outcomes are needed. Here, the Alamar Nucleic Acid-Linked Immuno-Sandwich Assay with next generation sequencing simultaneously quantified >120 central nervous system-related proteins in plasma collected from former collegiate athletes (N=401; 39% female; mean age 28.5 +/- 1.24 years) 5-10 years post-exposure. Participants were classified as High (HE; n=152) or Low Exposure (LE; n=249) based on sport (RHI proxy) participation during their collegiate careers. Separate linear models were conducted to 1) identify group differences in biomarkers between HE and LE and 2) identify associations of biomarkers with the number of prior concussions; all models accounted for sex, age, ethnicity, race, and body mass index. False discovery rate was applied to adjust for multiple testing. Seventeen biomarkers were significantly upregulated in HE relative to LE (p-fdr<0.05; Oligo Alpha-synuclein, Alpha-synuclein, Huntingtin, Malate dehydrogenase, Parkinson disease protein 7, Phosphorylated alpha-synuclein at serine 129, Superoxide dismutase [Cu-Zn], TAR DNA-binding protein 43, Presenilin-1, Annexin A5, Gamma-enolase, Neuronal pentraxin-2, RE1-silencing transcription factor, Pro-interleukin-16, S100-A12, RuvB-like 2, and Phosphoglycerate kinase 1). Three biomarkers were downregulated in HE relative to LE (p-fdr<0.05; Amyloid-beta precursor protein 38 and 40, Secreted frizzled-related protein 1). In contrast to RHI, there were no strong associations between biomarkers and number of prior concussions (p-fdr>0.10). These preliminary results suggest that proteomic markers of CNS disease processes are evident in plasma in former collegiate athletes 5-10 years following RHI exposure.
Co-Expression of 3R and 4R Tau Increases Synaptic Density and Preserves Cognition After Closed Head Injury in Mice
1SUNY Downstate Health Sciences University, Brooklyn, United States
Tau protein crosslinks microtubules but has poorly defined functions at the synapse. Tau isoforms have either 3 (3R) or 4 (4R) microtubule-binding sites. Microtubule-associated protein tau knock-in mice (MAPTKI) carrying the human tau coding sequence express all six human 3R and 4R tau isoforms, similar to adult humans. Wild-type (WT) mice express only three murine 4R tau isoforms. We compared WT C57Bl/6 mice with MAPTKI mice to determine whether differences in tau isoform expression alter traumatic brain injury (TBI) outcomes using a clinically relevant closed head injury (CHI) model. At 14 days post-injury, injured WT mice had cognitive and memory deficits on active place avoidance and the Barnes maze. Unexpectedly, the cognition and memory of injured MAPTKI mice were similar to those of uninjured MAPTKI, suggesting that human tau expression prevents cognitive and memory deficits. Active place avoidance and the Barnes maze require the activation of hippocampal synapses; therefore, I assessed synaptic density by measuring the colocalization of the presynaptic protein synaptophysin and the postsynaptic protein PSD-95 in the CA1 and CA3 regions of the hippocampus. Synaptic density in the CA1 stratum radiatum or CA3 stratum lucidum of uninjured MAPTKI mice was two-fold higher than that of WT mice. In addition, injured MAPTKI mice showed a trend toward higher synaptic density compared with injured WT mice. The higher synaptic density observed in MAPTKI mice may underlie the absence of cognitive deficits following CHI. The preserved cognition in MAPTKI mice after injury has broader implications for understanding TBI in humans.
Cognitive Decline Following Mid-Life and Later-Life Traumatic Brain Injury: Evidence from the Framingham Heart Study
1Department of Rehabilitation and Human Performance, Icahn School Of Medicine At Mount Sinai, New York, United States, 2Traumatic Brain Injury and Concussion Center, Department of Neurology, University of Utah School of Medicine, Salt Lake City, United States, 3Department of Neurology, Chobanian & Avedisian School of Medicine Boston University, Boston, United States, 4Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, United States, 5Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, United States
Background: Traumatic brain injury (TBI) is associated with increased risk of Alzheimer's disease and related dementias (ADRDs). Life stage at TBI may influence long-term clinical outcomes. We investigated domain-specific cognitive change following incident TBI in mid-to-later life.
Methods: Data were drawn from the Framingham Heart Study (Original and Offspring cohorts). Incident TBI was identified through medical chart review and modelled as a time-varying exposure. Within-between linear mixed effects models examined longitudinal cognitive change, adjusting for age, sex, education, cohort, and APOE-ℇ4 status. Exploratory analyses stratified participants by age at incident TBI: 40–70, and 70+ years.
Results: Of 2,781 participants, 411 (14.8%) experienced incident TBI. Those with incident TBI performed lower across all cognitive domains compared to those without TBI. Incident TBI was associated with within-person decline at next post-TBI study visit across all domains (Executive function: β=-0.09; language: β=-0.12; memory: β=-0.08, all p<.001); however, there was no subsequent acceleration in decline. Stratified analyses revealed divergent patterns. Those with incident TBI aged 70+ (n=303) demonstrated significant next-visit decline across all domains (β=-0.12 - -0.15; all p<.001) and no subsequent decline. While incident TBI at age 40–70 (n=108) showed no next-visit decline, there was a trend suggesting accelerated decline in executive function, equivalent to 2 additional years of cognitive aging per 5-year interval (β=-0.08, p=.04).
Conclusion: Incident TBI was associated with multi-domain cognitive decline post-TBI, but without subsequent acceleration. However, exploratory findings suggest midlife TBI has less immediate impact but may initiate accelerated decline in executive function. Findings are hypothesis-generating and require replication.
Complement-Mediated Neuroimmune Activation Drives Chronic Cognitive Decline After Repetitive Mild Traumatic Brain Injury
1Department of Pharmacology and Immunology, Medical University of South Carolina, Charleston, United States, 2Ralph Johnson VA Medical Center, Charleston, United States, 3Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, United States, 4Department of Dermatology, Medical University of South Carolina, Charleston, United States, 5Department of Regenerative Medicine & Cell Biology, Medical University of South Carolina, Charleston, United States, 6Department of Clinical Pharmacology, Faculty of Medicine, Alexandria University, Alexandria, Egypt, 7Institute for Global Food Security, School of Biological Sciences, Queens University Belfast, Belfast, United Kingdom, 8Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon, 9Department of Neurobiology, Center for Neurotrauma, Multiomics & Biomarkers, Morehouse School of Medicine, Atlanta, United States, 10Hollings Cancer Center, Charleston, United States
Introduction: Repetitive mild traumatic brain injury (rmTBI) is linked to persistent cognitive impairment and elevated neurodegenerative risk, but the mechanisms that maintain chronic pathology are unclear. Using a newly developed murine rmTBI model, we investigated whether complement activation is a central driver of post-injury neuroimmune dysfunction.
Methods: Mice received 12 mild impacts and were assessed for spatial learning and memory using the Barnes maze. Complement deposition and microglial morphology were quantified by immunofluorescence microscopy. We integrated RNA sequencing and quantitative proteomics to identify injury-associated molecular pathways. Complement was inhibited with CR2-Crry, a targeted inhibitor of all complement pathways. Subacute and chronic cohorts were analyzed to evaluate both early and persistent molecular and behavioral changes. This work was funded by the U.S. Department of Veterans Affairs, National Institutes of Health, and Brain Injury Association of America.
Results: rmTBI resulted in significant cognitive deficits as detected on the Barnes Maze, robust C3 deposition in vulnerable brain regions, and an activated microglial state. Multi-omic integration revealed coordinated increases in complement components, inflammatory mediators, synaptic regulatory pathways, and neurodegeneration-associated signatures, with enrichment of immune effector and neurodegenerative networks. CR2-Crry reduced C3 deposition, normalized microglial morphology, improved cognition, and blunted injury-induced transcriptomic and proteomic pathways. Longitudinal analyses showed persistent complement activation and behavioral deficits months after injury, both attenuated by early complement inhibition.
Conclusion: Complement activation is a driver of sustained neuroimmune activation and cognitive decline after rmTBI. Targeted complement inhibition mitigates progressive dysfunction after rmTBI, supporting complement-directed strategies as potential disease-modifying therapies in neurotrauma.
Computational Schema to Decode Ependymal-Driven CSF Flow Patterns in Post-traumatic Hydrocephalus
1University of Pittsburgh, Pittsburgh, United States
A complication of TBI is hydrocephalus, characterized by abnormal cerebrospinal fluid (CSF) accumulation and ventricular enlargement. Mechanisms underlying post-traumatic hydrocephalus (PTH) remain understudied, but ependymal ciliary loss and decreased CSF flow are implicated post-TBI. The goal of this project is to establish a computational pipeline to analyze ependymal cilia-driven CSF flow patterns in mice with PTH. We established an ependymal near-wall ciliary flow assay to quantify fluorescent bead velocity as a measure for ependymal ciliary function. Fresh ependymal tissues were harvested from the lateral ventricles and maintained in physiological buffer. Fluorescent beads were added to the “cilia carpet” to quantify velocity using fluorescent video microscopy. Motion vectors and dynamics of the flowing beads through ependymal tissues were quantified and computed using Particle Image Velocimetry (PIV) with the MQD algorithm. After calculation of vector motion fields, each bead from the previous step was assigned to a set of vectors and the motion of that bead. Vector metrics such as divergence, curl, and Laplacian were characterized to quantify the ciliary dynamics. Then, each video was rearranged into a grid and stitched together to reconstitute the entire ventricle. We stitched ∼400 flow videos from a lateral ventricle to create a flow map for each animal. Dice score-based comparison of automated segmentations and ground truth manual segmentations of bead flow showed validation of automated pipeline. Quantitative flow analysis demonstrated that PTH mice presented with a reduction in overall flow velocity and reduced angular velocity, which contribute to abnormal neuronal and CSF homeostasis in PTH.
Concussion Symptoms Associated with Same-Day Head Impact Exposure in Collegiate Rugby Players
1Virginia Tech, Blacksburg, United States
The objective of this study was to examine the association between subconcussive head impact exposure (HIE) and changes in symptom reporting and Pupillary Light Reflex (PLR) metrics. Twenty-one male collegiate rugby players wore instrumented mouthguards (Prevent Biometrics) during seven 15s rugby games. Before and after each game, players completed a graded symptom checklist and PLR measurement (PLR-4000, NeurOptics). For each player, the change in Symptom Severity Score (SSS) and PLR metrics were calculated by subtracting baseline from post-game measurements. Players were classified as having elevated symptoms if SSS increased ≥ 7, which occurred in 18.4% of player matches throughout the season. Linear mixed models were used to determine the association between HIE and change in SSS and PLR with player as a random effect. Metrics included total head impacts, impacts ≥ 30 g, and maximum peak linear acceleration (PLA) across three windows: this game, past 7 days, and season to date. Associations varied between HIE and PLR response across windows and metrics. Total head impacts this game (β = 0.20, p = 0.013) and impacts ≥ 30 g this game (β = 1.21, p = 0.048) were significantly associated with change in SSS. In a generalized linear mixed model, total head impacts this game were significantly associated with increased odds of elevated symptoms (odds ratio = 1.10, p = 0.042). Data suggest that within-day HIE has the largest effect on symptom reporting, with diminishing effects as the time window is extended.
Concussive Injury Modulates Neurogenesis and Circuit Function in Human Forebrain Organoids
1University of California Riverside, Riverside, United States
Traumatic brain injury (TBI) disrupts neurogenesis and neural circuit function, yet species differences limit the translational relevance of rodent models. We developed a regionally specified human forebrain organoid (hFBO) platform to model concussive injury across developmental stages. Human induced pluripotent stem cells were differentiated into dorsal (glutamatergic) and ventral (GABAergic) hFBOs using dual SMAD inhibition. Regional and developmental specifications were assessed by immunohistochemistry for neural progenitor and neuronal subtype markers. Functional maturation was evaluated using whole-cell patch-clamp electrophysiology and synaptic recordings. Concussive injury was induced using the Cell Injury Controller II. Cell death, neurogenic responses, and injury signaling were assessed by immunostaining, and network activity was examined using calcium imaging. Early-stage organoids (25 days in vitro, DIV) exhibited neural progenitor markers (Nestin, SOX2) and ventricular zone–like structures marked by ZO1, whereas later-stage (80 DIV) showed neuronal subtype specification with glutamatergic neurons (CTIP2) enriched in dorsal organoids and GABAergic interneuron markers (GABA, SST) in ventral organoids. Electrophysiological recordings revealed neuronal maturation, with rudimentary action potentials at 80 DIV and repetitive firing and spontaneous synaptic activity by 150 DIV. Concussive injury produced severity-dependent increases in TUNEL-positive cell death. Moderate injury increased expression of progenitor and proliferation markers (SOX2, Nestin, Ki67) three days post-injury in dorsal and ventral hFBOs. Calcium imaging at 150 DIV revealed injury severity–dependent increases in intracellular calcium consistent with network hyperexcitability. These findings establish a human organoid-based TBI model that captures neurogenic and circuit-level responses to concussive injury in a human-relevant system.
Keywords: Human forebrain organoids, Neurogenesis, Concussive injury
Connecting the Spots: Applying the Void-Spot-Assay and Machine Learning to Evaluate Urinary Function and Behavior After Spinal Cord Injury
1Spinal Cord Injury Research Group (SCIRG), School of Biomedicine, Adelaide University, Kaurna, Adelaide, Australia, 2SpineLabs Adelaide, School of Medicine, Adelaide University, Kaurna, Adelaide, Australia, 3School of Science, Western Sydney University, Penrith, Australia, 4IIMPACT in Health, College of Health, Adelaide University, Kaurna, Adelaide, Australia
Regaining bladder function is a priority for individuals with spinal cord injury (SCI). However, only 3.1% of preclinical studies include urological outcomes, as current assessments are invasive, complicated, and necessitate animal sacrifice. The void spot assay (VSA) involves placing animals on filter paper, which is imaged to evaluate urinary outcomes. We aimed to adapt the VSA as a non-invasive urological assessment for SCI rats, assess sex differences in outcomes, and apply machine learning to evaluate urinary behavior.
Female and male Sprague Dawley rats were randomized into groups: naïve (n=4/sex), sham (females=7, males=8), or SCI (T10, 200kdyne; n=8/sex). VSAs were performed at baseline and days 2-15 post-SCI to assess function (voided volume, residual urine, bladder capacity, voiding efficiency) and behavior (void location). Convolutional neural networks (CNNs) were trained on urination patterns to predict sex. Statistical analysis was conducted using linear mixed models and Fisher's exact test.
For both sexes, voided volume, residual urine volume, and bladder capacity significantly increased after SCI, whereas voiding efficiency decreased (p < 0.001). Urinary functional deficits were significantly greater and lasted longer in males. The largest void for males occurred significantly more often in the center (p<0.001) than females, who preferred voiding along the edges (p=0.01). CNNs distinguished male and female post-SCI voiding patterns with 92.7% accuracy.
We establish the VSA as a non-invasive urological test and demonstrate sex differences in voiding function and behavior post-SCI. Our findings may increase the number of studies incorporating urological outcomes, paving the way for future treatment development.
Continuous, Unsupervised, Time-Lapse Miniscope Imaging Captures Microglial Pathodynamics After Closed-Head Injury
1University of Michigan Concussion Center, Ann Arbor, United States, 2University of Michigan, Physical Medicine and Rehabilitation, Ann Arbor, United States, 3University of Michigan, Emergency Medicine, Ann Arbor, United States, 4University of Michigan, Electrical Engineering and Computer Science Department, Ann Arbor, United States, 5University of California Riverside, Biomedical Sciences Department, Riverside, United States, 6University of Colorado Boulder, Integrative Physiology, Boulder, United States
Traumatic brain injury (TBI) initiates dynamic pathophysiological processes marked by changes in cellular movement, vascular function, and inflammation. Microglia respond rapidly to TBI, exhibiting shifts in motility, spatial distribution, and cell-cell interactions. But current experimental approaches are restricted to discrete snapshots, limiting observations between time points to inference. Therefore, we developed continuous unsupervised time-lapse imaging of cortical microglia before and after closed-head injury in mice. A male Cx3cr1-eGFP mouse underwent implantation of a 3mm cranial window and baseplate. A v4.4 miniscope continuously imaged the mouse cortex (0.5 image/min,1 mm x 1 mm) for 20 hours pre-injury. The miniscope was swapped for a protective cap and a 100g weight was released from 94cm, producing a closed-head injury at the site of the imaging window. Post-injury imaging resumed 30 minutes after injury and continued for 29 hours. Time-lapse images were processed in Python using a tophat morphological filter and watershed segmentation to identify cells. The Hungarian algorithm was applied to centroids to track locations across frames. Following closed-head injury, the proportion of motile microglia increased from 13% to 43% and median velocity increased from 1.01 μm/min to 2.68 μm/min by the second post-injury dark period. Microglia movement relative to a penetrating blood vessel was quantified in a 100 μm x 100 μm region. Pre-injury microglia exhibited no directional bias relative to the blood vessel, while post-injury microglia showed directional homing toward the vessel. These data capture TBI pathodynamics, providing a framework to resolve the temporal relationship between microglial responses and cerebrovascular dysfunction.
Cortical Spreading Depolarizations Amplify Epileptic Spikes in Rat Model of Traumatic Brain Injury
1University of Cincinnati College of Medicine, Cincinnati, United States, 2University Of Cincinnati, Cincinnati, United States
Nearly 1 in 50 patients who experience a traumatic brain injury (TBI) develop post-traumatic epilepsy (PTE). Identifying high-risk patients is vital for guiding care but is often hindered by our limited understanding of the pathogenesis of PTE. Cortical spreading depolarizations (CSDs) are self-propagating waves of mass neuronal depolarizations that occur in 60% of acute TBI patients and can disrupt hippocampal physiology. Given the role of hippocampal circuitry in epileptogenesis, we hypothesized that CSDs increase the risk of PTE by facilitating pathologies such as mossy fiber sprouting. To test this hypothesis, adult male Sprague Dawley rats received a moderate TBI via lateral fluid percussion injury, followed by cortical application of potassium chloride to induce CSDs (TBI+CSD, n = 4) or saline for controls (TBI, n = 4). Six months post-injury, video-electroencephalography (EEG) was used to monitor the animals during a pentylenetetrazole (PTZ) challenge, a well-established model for seizure susceptibility in rodents. One month later animals were euthanized, and brain tissue was processed for Zinc Transporter 3 (ZnT3) immunohistochemistry, a marker of mossy fiber sprouting. We found no difference in latency to first PTZ-induced seizure [two-tailed Student’s T test, p > 0.05]. Interestingly, a linear mixed-effects model revealed that TBI+CSD rats exhibited epileptic spikes with significantly larger EEG amplitude than controls [p = 0.0056]. Qualitative histological findings between TBI+CSD and TBI tissue indicate similar patterns of ZnT3 positivity in the hippocampal dentate gyrus. These initial findings suggest CSDs may promote neuronal hyperexcitability during epileptic events without appreciable mossy fiber sprouting.
Cortical Spreading Depolarizations Increase Aquaporin-4 Expression in a Rat Model of Traumatic Brain Injury
1University Of Cincinnati College of Medicine, Cincinnati, United States, 2Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, United States
Cortical spreading depolarizations (CSDs) are pathological waves of mass depolarization that disrupt cerebral ion homeostasis. CSDs occur in 60% of moderate-severe traumatic brain injury (TBI) patients and are associated with poor 6-month outcomes. We demonstrated in a rat model of TBI that CSDs induced 3-days-post-injury (dpi) caused increased cerebral blood flow compared to CSDs induced at 0 or 7dpi. Given the critical role of astrocytes in mediating cerebral blood flow, we hypothesized that 3dpi-CSD animals would exhibit increased cyclooxygenase-1 (COX-1), a marker of astrocyte-mediated vasodilation, and decreased aquaporin-4 (AQP4), a contact-dependent astrocytic water channel present at vascular interfaces, secondary to decreased astrocyte-vessel interactions. Adult male Sprague Dawley rats (n=16) underwent lateral fluid percussion injury and received no-CSD (controls) or CSDs at 0dpi, 3dpi, or 7dpi. Brain tissue was processed for immunofluorescence and vasculature was reconstructed via confocal microscopy. At the injury center, 3dpi-CSD animals had significantly increased vessel diameter [one-way ANOVA, p=0.046] compared to controls. Contrary to our hypothesis, we found decreased COX-1 [p=0.047] and increased AQP4 expression [p=0.009]. These findings suggest a COX-1-independent vasodilatory response at 3dpi-CSD, possibly reflecting increased osmotic forces driven by AQP4. Overall, our results indicate that CSDs modulate astrocyte-vessel interactions and may underlie potentially pathologic vasodilation and hyperemia. Such vascular alterations raise the possibility that CSDs disrupt physiologic water flux compatible with edema formation. The 3-day temporal pattern of increased AQP4 following CSDs suggests a potential target for future therapeutic intervention in TBI patients with CSDs.
Cracking the Code of Baroreflex Dysfunction After Spinal Cord Injury
1Dalton Cardiovascular Research Center, Department of Pathology and Anatomical Sciences, Department of Physical Medicine and Rehabilitation, University of Missouri School of Medicine, Columbia, United States
Blood pressure instability contributes substantially to mortality after high-level spinal cord injury (SCI). The arterial baroreflex stabilizes hemodynamics through coordinated sympathetic and parasympathetic control. After SCI, supraspinal regulation of sympathetic outflow is disrupted while parasympathetic pathways persist intact, leading to imbalanced autonomic activity and subsequent baroreflex dysfunction to maintain blood pressure. However, SCI-induced baroreflex dysfunction remains poorly understood. Clinical findings are variable and experimental animal models have rarely been examined. To elucidate the change of baroreceptor-mediated cardiovascular and sympathetic reflexes following SCI, adult rats underwent T2/3 spinal cord crush and survived for 10 weeks. Baroreflex function was assessed in thiobutabarbital (Inactin) anesthetized rats by simultaneously recording mean arterial pressure (MAP), heart rate (HR), and splanchnic sympathetic nerve activity (sSNA) during pressor and depressor stimulation. Four-parameter logistic modeling revealed that uninjured animals had robust negative relationships between MAP-HR and MAP-sSNA. In contrast, SCI rats exhibited positive gains and prolonged recovery time. As Inactin suppresses vagal activity, the reversed cardiac baroreflex response in SCI rats may result from anesthesia-induced attenuation of parasympathetic tone that was elevated. To explore potential therapeutic strategies, a separate cohort of SCI rats received embryonic brainstem-derived neural progenitor cell (BS-NPC) transplantation and/or passive hindlimb cycling (PHLC) exercise training for 10 weeks. Consequently, PHLC alone partially restored MAP-HR and MAP-sSNA coupling while transplantation alone further increased positive gain. Combined treatment yielded effects similar to exercise alone. In conclusion, high-level SCI changes cardio-sympathetic baroreflex function. Exercise but not cell transplantation, improves baroreflex responses and may enhance cardiovascular stability after SCI.
CT-Independent Mortality Prediction After Traumatic Brain Injury Using Soft-Voting Machine Learning: A Multicenter Study
1Kobe University Graduate School of medicine, Kobe, Japan, 2Hyogo Prefectural Harima Himeji Medical Center, Himeji, Japan, 3Hyogo Emergency Medical Center and Kobe Red Cross Hospital, Kobe, Japan, 4Hyogo Prefectural Kakogawa Medical Center, Kakogawa, Japan, 5Hyogo Prefectural Awaji Medical Center, SUmoto, Japan, 6Kita-harima medical center, Ono, Japan
Assessing the severity of traumatic brain injury (TBI) is challenging due to its heterogeneous and multifactorial pathophysiology, particularly in resource-limited settings. We developed CT-independent outcome prediction models using 13 predictors available at presentation and recently reported tabular foundation models.
This retrospective study included 1,200 patients with blunt TBI from six Japanese hospitals. The dataset was randomly split into training (n=1,000) and test (n=200) sets. We evaluated several machine learning models, including pre-trained tabular foundation models (TabDPT, TabSTAR, TabICL, TARTE, and CARTE), and constructed a soft-voting ensemble model using some of these models. This model was compared with logistic regression, IMPACT-Core, and the MOST score.
Among the 1,200 patients, the median age was 71 years, 166 (13.8%) had severe TBI, and 86 (7.2%) underwent emergent craniotomy. The median hospital stay was 13.0 days, and 61 patients (5.1%) died in the hospital. On the test set, the soft-voting machine learning model and the logistic regression model showed nearly equivalent results: 58.3% sensitivity, 98.4% specificity, 70.0% positive predictive value, 96.0% accuracy, an F1 score of 0.636, and an AUROC of 0.91. IMPACT-Core and the MOST score showed the highest sensitivity (75.0%); however, their positive predictive value was insufficient (33.3%). No tabular foundation model consistently outperformed conventional approaches.
These results suggest that while conventional scores had high sensitivity, they also had high false-positive rates. Furthermore, triage-oriented prognostic prediction was feasible with reasonable validity using generalized linear models, without requiring complex nonlinear models. Accurate CT-independent prediction may support clinical decision-making in resource-limited settings.
Data Field Matching in Traumatic Brain Injury Studies Using Micro Large Language Models
Dr. Ilhan Bok1, Dr. Frederic Sala1, Dr. Abel Torres-Espin2, Dr. Vikas Singh1, Justin Wong3, Dr. Geoffrey Manley3, Dr. Michael McCrea4,
1University of Wisconsin - Madison, Madison, United States, 2University of Waterloo, Waterloo, Canada, 3University of California-San Francisco, San Francisco, United States, 4Medical College of Wisconsin, Milwaukee, United States
Introduction: Large language models (LLMs) have seen recent major theoretical advances applicable to database harmonization. Multi-site clinical study datasets potentially represent rich sources for disease modeling and analysis, but retrospective studies of these data sources are often not reproducible when applied to independently gathered datasets. Field matching is an essential first step in study harmonization.
Objective: To match candidate data fields across the large multi-site, previously completed observational acute TBI clinical studies TRACK-TBI and CENTER-TBI.
Methods: We first generated full lists of cosine embeddings vectors from full field names using the all-MiniLM-L6-v2 sentence transformer. A complete cosine similarity matrix between all permutations of variables was interpreted as private preference rankings for the Gale-Shapley stable marriage algorithm and then iteratively matched. Matches with identical field names were verified using Meta® Llama 3.2-generated data descriptions.
Results: For 770 total matches, we omitted 200 entries with identical field names. Matches for CENTER measured 171.56 ± 125.26 chars with Shannon entropy of 4.217 ± 1.437 (skew -1.476) nats and for TRACK measured 85.56 ± 50.01 chars with Shannon entropy 4.236 ± 0.627 (-0.809) nats. We found a substantial R2 = 0.5808 compared to Levenshtein distance (λ). We found significant heteroskedasticity (p = 1.89 × 10-10) using a Chi-squared test with Lagrange multiplier value of 44.778 from White’s test.
Conclusion: Micro LLMs represent a possible advance over natural language processing methods in assisting the harmonization of clinical studies with one another, including TBI studies.
Data Field Transformation for Formatting Harmonization in Traumatic Brain Injury Studies Using Micro Large Language Models
Dr. Ilhan Bok1, Dr. Frederic Sala1, Dr. Vikas Singh1, Dr. Abel Torres-Espin2, Justin Wong3, Dr. Geoffrey Manley3, Dr. Michael McCrea4,
1University of Wisconsin - Madison, Madison, United States, 2University of Waterloo, Waterloo, Canada, 3University of California-San Francisco, San Francisco, United States, 4Medical College of Wisconsin, Milwaukee, United States
Introduction: Input from multiple independently gathered large clinical studies provides a potentially rich source of data for clinical analysis with high potential for external validity. However, harmonization between these databases has been held back by formatting and notation differences between studies. Field transformation using Micro LLM-generated code for this purpose has not yet been attempted.
Objective: Transform previously matched data fields across the large multi-site, previously completed observational acute clinical TBI studies TRACK-TBI and CENTER-TBI to allow for pooled or federated analysis.
Methods: Subroutines were iteratively generated across the matched data field sets. Data samples for matched fields were supplied to Meta® Llama 3.2 along with the prompt: “Return a Python function to transform to a common language. Provide code only, no prose.” Output was automatically evaluated using a manual interpreter. Data fields without valid entries were excluded.
Results: We tokenized the generated transformation subroutines and identified the following tokens related to transformation: `transform_to_common_language` (n = 1347 occurrences), `center_tbi` (n = 885), `center_tbi_data` (n = 591), `track_tbi` (n = 619), and `track_tbi_data` (n = 392) within the 25 most frequent. Log-normal distribution was assumed for average line length (38.5 ± 0.48 characters). Levenshtein distance was 8.14 ± 7.17 characters for transformed entries (n = 295).
Conclusion: Despite deep differences in data structure and content, micro LLMs can assist transformation of clinical data entries for harmonization, including for TBI studies.
Delirium After Traumatic Brain Injury: High Prevalence, Low Recognition in Older Adults
1University of California, San Francisco, San Francisco, United States, 2Buck Institute for Research on Aging, Novato, United States, 3Sheba Medical Center, Tel HaShomer, Ramat Gan, Israel, 4Tel Aviv University, Tel Aviv, Israel
Objectives: To evaluate agreement between prospectively administered Confusion Assessment Method (CAM) and retrospective chart-based delirium screening in older adults with traumatic brain injury (TBI) and identify predictors of discordance.
Methods: Adults 65 years and older presenting to a Level 1 Trauma Center within 72 hours of TBI underwent daily CAM on weekdays throughout hospitalization. Chart-based delirium was ascertained using CHART-DEL under narrow (definite/probable) and broad (definite/probable/possible) criteria. Diagnostic accuracy was evaluated against CAM as the reference standard using Cohen’s kappa and standard metrics. Multivariable logistic regression identified clinical predictors of discordance.
Results: Among 50 subjects (median age 78 years, 56% women, median arrival GCS 15), 31 met CAM criteria for delirium. Only 5 CAM-positive subjects were documented as delirious in the medical record. Chart-based agreement was substantially higher under broad (κ=0.66, sensitivity 0.87, specificity 0.79) than narrow (κ=0.35, sensitivity 0.42, specificity 1.00) criteria. Discordance was driven primarily by under-recognition of inattention, a core diagnostic feature, in documentation (κ=0.18, sensitivity 0.35, specificity 1.00). ICU admission (OR 4.94, p=0.028) and traumatic findings on head CT (OR 5.06, p=0.015) were independently associated with greater inattention agreement.
Conclusions: Delirium affects nearly two-thirds of older TBI patients yet remains largely unrecognized in routine documentation. Broad CHART-DEL criteria, favoring sensitivity over specificity, achieve substantial agreement with in-person CAM, while narrow criteria miss the majority of true cases due to inattention under-documentation. Structured inattention screening in non-ICU settings represents a key modifiable target.
De-Novo Post-Injury Substance Use Is Associated with Poorer 12-Month Multidimensional Outcomes After GCS 13-15 Traumatic Brain Injury: A TRACK-TBI Study
1University Of California, San Francisco, San Francisco, United States, 2University of Pittsburgh Medical Center, Pittsburgh, United States, 3University of Washington, Seattle, United States, 4Leiden University Medical Center, Leiden, The Netherlands, 5University of Michigan, Ann Arbor, United States, 6Medical College of Wisconsin, Milwaukee, United States, 7Harvard Medical School, Boston, United States, 8University of Wisconsin-Madison, Madison, United States, 9University of Pennsylvania, Philadelphia, United States, 10University of Texas Southwestern Medical Center, Dallas, United States, 11University of California, San Diego, San Diego, United States
Objectives: Substance use disorders are prevalent in neurotrauma populations. While pre-injury substance use is associated with disability after traumatic brain injury (TBI), relationships between new post-injury substance use and outcomes are not well-characterized. We examined associations between de-novo illicit/non-prescription substance use (DNSU) and 12-month outcomes.
Methods: The TRACK-TBI Study prospectively enrolled TBI patients across 18 Level 1 trauma centers within 24-hours post-injury. This analysis included subjects aged ≥17-years, arrival Glasgow Coma Scale score 13-15, without pre-injury substance use. Outcomes in subjects with/without DNSU (DNSU+/DNSU-) were examined at 12-months across functional recovery (GOSE), post-concussive symptoms (RPQ), psychological-distress (BSI-18), depression (PHQ), post-traumatic stress (PCL-5), quality-of-life (QOLIBRI), pain (PROMIS-Pain), and insomnia (ISI) domains. Predictors were analyzed using multivariable regression models. Covariate-adjusted proportional odds ratios (aOR), covariate-adjusted mean differences (aMD), and [95% confidence intervals] were reported.
Results: In 1102 TBI subjects (DNSU+: 7.7%), DNSU+ were younger (mean±SD: 36.7±18.2 vs. 46.6±16.7-years, p<0.004), more likely to have Medicaid (21% vs. 7%, p<0.001) and high-risk alcohol intake (53% vs. 35%, p<0.001). At 12-months, DNSU+ was associated with poorer functional recovery (aOR=0.56 [0.35-0.88]) and worse cross-domain symptoms burden: post-concussive (aMD=+3.64 [0.12-7.17]), psychological-distress (aMD=+5.30 [2.52-8.08]), post-traumatic stress (aMD=+6.92 [2.42-11.42]), depression (aMD=+2.43 [1.04-3.82]), pain (aMD=+0.34 [0.07-0.61]), insomnia (aMD=+3.07 [1.09-5.05]). DNSU+ was associated with higher quality-of-life scores (aMD=+7.31 [1.78-12.84]).
Conclusions: Post-TBI DNSU was associated with poorer 12-month outcomes, underscoring its role as a modifiable risk factor in longitudinal recovery. DNSU-related recovery trajectories are complex and potentially bidirectional, warranting investigation into causal mechanisms and social determinants to inform strategies for early intervention.
Designing and Characterizing an MRI compatible Rat Degenerative Cervical Myelopathy Model
1Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, United States, 2Department of Physiology, University of Kentucky, Lexington, United States, 3Novoron Bioscience, San Diego, United States
Degenerative Cervical Myelopathy (DCM) is caused by age-related degeneration of the spine resulting in chronic, progressive compression of the cervical spinal cord. DCM is the most common cause of non-traumatic spinal cord injury. Symptoms often include numbness and tingling of the hands, later progressing to a loss of dexterity, balance, and locomotor function. MRI-based imaging of the spinal cord is used for diagnosis in clinic. Currently, there are no additional tools to enhance prognostics and develop better treatments for this highly prevalent condition. We have chosen to develop a screw-based rat model for DCM that mimics the human condition and is gradual in severity. Other screw-based models for DCM were not compatible with MRI screening. To effectively test for additive treatments beyond surgery, a model that can account for varying degrees of degeneracy while also being MRI imaging compatible must be formed. We have done this by securing a nut and screw onto the spinal cord that can be tightened gradually. Compression of the rat cervical spine across three groups will be characterized using MRI imaging and measurement of sensory and motor deficits. Groups one and two will undergo screw tightening surgeries with gradual compression until 75% or 90% compression is reached. While group three will represent a sham surgery. From these studies we aim to better understand the sensory and functional decline along with the immunological response to chronic compression in DCM. Gained insight will progress further research and approaches when dealing with treatment options for patients with DCM.
Detection of Cortical Spreading Depolarizations in Traumatic Brain Injury Using Acoustic-Inspired Spectral Features in Electrocorticography
1Hennepin Healthcare Research Institute, Minneapolis, United States
Objective: To develop and validate an automated detection method for cortical spreading depolarizations (CSDs) based on acoustic-inspired spectral features, enabling efficient and reliable identification in noisy clinical electrocorticography (ECoG) recordings and overcoming the limitations of labor-intensive manual review.
Methods: The method was evaluated on 51 days of DC-coupled ECoG data from 8 patients with traumatic brain injury (TBI) after craniotomy or craniectomy, acquired using 32 electrodes in four eight-contact subdural strips. Acoustic-inspired spectral features, including time-frequency metrics, were extracted from continuous two-minute epochs. These features were used to capture the characteristics of CSD, a prominent slow negative potential shift (<0.05 Hz) and concurrent suppression of high-frequency activity over the 4 Hz band.
Results: CSDs were detected in six of eight patients. A total of 1,315 events were identified, with a sensitivity of 78.16%, precision of 85.7%, and area under the receiver operating characteristic curve (AUC) of 88.93%. Average processing time per event was 0.154 minutes, substantially reducing manual annotation effort. The selected features showed greater robustness to clinical noise and artifacts than non-CSD signals.
Conclusion: This efficient and robust automated detection method accelerated large-scale analysis of CSDs, and demonstrated strong agreement with expert manual annotations. By addressing the challenges of labor-intensive manual review and mitigating the impact of clinical noise and artifacts, the approach enables more comprehensive CSD investigations and paves the way for translation to real-time bedside monitoring in the neuro intensive care unit.
Development and Implementation of a Standardized Framework for the Clinical Diagnosis of Traumatic Brain Injury in Adults: a TRACK-TBI Study
1Department of Neurological Surgery, University of California, San Francisco, San Francisco, United States, 2Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital, San Francisco, United States, 3Weill Institute for the Neurosciences, University of California, San Francisco, San Francisco, United States, 4Division of Emergency Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, United States, 5Department of Pediatrics, Harvard Medical School, Boston, United States, 6Department of Neurosurgery, Oklahoma University Health, Oklahoma City, United States, 7Department of Neurosurgery & Neurology, Medical College of Wisconsin, Milwaukee, United States, 8Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, United States, 9Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States, 10Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States, 11Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States, 12Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, United States, 13Department of Emergency Medicine, University of Rochester School of Medicine and Dentistry, Rochester, United States
Traumatic brain injury (TBI) is difficult to diagnose in patients without definitive intracranial lesions on computed tomography (CT) scan. Neurological signs and symptoms may be confounded by systemic injuries and non-TBI-related insults, hindering accurate classification of TBI severity, triage to care, and stratification for clinical trial inclusion. In a multicenter prospective cohort study, we describe the development and iterative refinement of an adjudication framework for TBI diagnosis.
The TRACK-TBI Pilot Aid in Diagnosis study enrolled patients aged≥18 years presenting to three US trauma centers with a plausible TBI mechanism and either no CT or a negative head CT for acute intracranial pathologies. Subjects with blood collected within 24 hours of injury and a 2-week research MRI were adjudicated by twenty TBI experts across five iterative rounds. Process improvements were made in response to low (<75%) agreement and Fleiss’ kappa inter-rater reliability (IRR).
Overall agreement (Round (R)1/2/3: 83%/90%/89%), IRR (R1/2/3 k: 0.55/0.56/0.65), and percentage of subjects with <75% agreement (R1/2/3: 31.2%/12.5%/20%) improved across adjudication R1-3. Ten adjudicators participated in R4 and three in R5, partly accounting for lower agreement (R4/5: 84%/85%) and IRR (R4/5 k: 0.55/0.38). Using the R5 adjudicators’ responses across all 71 adjudicated subjects, overall agreement was 90.1% and IRR was 0.56.
Our clinical adjudication framework for diagnosis showed fair-to-substantial agreement encapsulating objective clinical data, neuroimaging, and clinical signs not better accounted for by confounders in a plausible, initially indeterminate TBI cohort. Continued implementation and validation of this framework will advance precision medicine approaches for TBI diagnosis and classification.
Development of an AI-Driven Tool to Characterize Vascular-Related Glial Changes Following Repeated Mild Blast Traumatic Brain Injury
1University Of Kentucky, Lexington, United States
A major hallmark of blast-induced TBI is glial dysfunction, which can be exacerbated around blood vessels due to neurovascular damage. We hypothesized that glial changes occur in a time-dependent manner after repeated mild blast TBI (rmbTBI) and that changes will be heightened around blood vessels. Therefore, we sought to define astrocytic and microglial responses around blood vessels following rmbTBI at 1-day, 7-days, and 5-months post blast. Rats were assigned into groups (sham and rmbTBI) and time points (acute (1-day post-blast, n=6/group), sub-acute (7-day post-blast, n=6/group), and chronic (5 months post blast, n=12/group)). rmbTBI rats were exposed to two 11 psi static peak overpressure blast waves at a 24h interval. Hemibrain slices were stained for IBA-1 and GFAP, and a HALO AI MiniNet classifier was trained to recognize blood vessels. ROIs include the cortex, hippocampus, amygdala, and corpus callosum. In the 1-day timepoint, there was a decrease in IBA-1 expression in the amygdala (p=0.048), hippocampus (p=0.015), and cortex (p=0.021) and a decrease in GFAP in the amygdala (p=0.014) of the rmbTBI groups. There were no other significant differences in the expression of GFAP, although there is a trend of decreased GFAP expression in all ROIs in the rmbTBI group 1-day timepoint. Although glial dysfunction resolves by 7 days, GFAP expression is significantly enriched around blood vessels despite treatment group. Thus, rmbTBI decreases astrocyte GFAP expression and microglial IBA-1 expression in early time points that resolve over time.
Development of an Ultra-Selective DYRK1A Inhibitor as an Acute Therapeutic Strategy for Repeated Head Trauma
1The Roskamp Institute, Manatee County, United States, 2James A. Haley Veterans' Hospital, Tampa, United States, 3Biosplice Therapeutics and TenaRx, San Diego, United States
Background: Dual-specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A) phosphorylates Tau at multiple residues, priming Tau for pathological hyperphosphorylation after brain injury. DYRK1A also regulates inflammatory signaling and cellular responses to DNA damage, processes activated early following brain injury. Targeting DYRK1A during the acute post-injury window may therefore mitigate secondary injury mechanisms and limit the progression of tau pathology.
Methods: Human Tau (hTau) transgenic mice received five repeated head injuries RHI administered 48 hours apart. Treatment with the ultra-selective DYRK1A inhibitor SM15685 supplied by TenaRx (10 or 20 mg/kg) began 1 hour after the final injury and continued daily for 21 days. Behavioral assessments included Rotarod, Barnes Maze, elevated-plus maze (EPM), and optomotor response. Neuropathology evaluated GFAP, Iba1, and oligodendrocyte-associated tau pathology. Plasma biomarkers (GFAP, NFL, and total Tau) were quantified using the MSD S-PLEX assays.
Results: Injured animals displayed persistent motors and visual deficits. Treatment with SM15685 improved motor coordination, with injured mice approaching sham performance by Day 17. SM15685 also improved visual tracking responses and partially normalized behavioral alterations in the EPM. Histological analyses revealed reduced microglial activation and astrocytosis in the brainstem, along with reductions in oligodendrocyte-associated p-tau. Plasma biomarker analysis demonstrated reduced GFAP and neurofilament light levels during the sub-acute phase following treatment.
Conclusion: Acute DYRK1A inhibition with SM15685 attenuates early neuroinflammation, axonal injury biomarkers, and tau pathology while improving functional outcomes after RHI. These findings support DYRK1A inhibition as a promising acute therapy to limit secondary injury and warrant further study of its effects on chronic RHI outcomes.
Dexmedetomidine Combined with Hypothermia Synergistically Suppresses Inflammasome Activation and Promotes Reparative Immunity After Spinal Cord Injury
1Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, United States, 2Spinal Cord and Brain Injury Research Group, Stark Neuroscience Research Institute, Indianapolis, United States, 3Department of Anesthesia, Indiana University School of Medicine, Indianapolis, United States, 4Department of Pathology & Laboratory Medicine, Indiana University School of Medicine, Indianapolis, United States, 5Neuroscience and Behavioral Biology, Emory University, Atlanta, United States
Spinal cord injury (SCI) triggers persistent systemic inflammation that contributes to progressive multi-organ dysfunction. Targeting this inflammatory cascade is critical for improving recovery. Dexmedetomidine (DEX), an α2-adrenergic agonist widely used clinically, and therapeutic hypothermia both exhibit anti-inflammatory properties. Our previous work demonstrated that DEX-induced hypothermia significantly improves locomotor and bladder recovery post-SCI compared with either treatment alone. Here, we investigated the synergistic anti-inflammatory mechanisms of this approach and and the cellular mechanisms involved. A single intraperitoneal dose of DEX (100 μg/kg) administered 1h after a T10 contusive SCI was combined with controlled moderate hypothermia for 16h. Mice were evaluated for six weeks using multiplex cytokine assays, flow cytometry, histology, and IVIS imaging using a caspase-1 luciferase reporter line. Cytokine profiling revealed robust early suppression of pro-inflammatory IL-6, IFN-γ, and G-CSF at 24h, exceeding the effects of DEX or hypothermia alone, followed by increased anti-inflammatory IL-10 at 14d. Tissue macrophage accumulation was reduced at 6 week. Flow cytometry and immunostaining (6h–7d) demonstrated decreased monocyte and neutrophil infiltration and a shift toward reparative M2-like monocytes, most prominent at day 3. IVIS imaging revealed widespread NLRP3/caspase-1 activation post-SCI through four weeks. A single DEX dose significantly suppressed inflammasome activity in vivo, confirmed ex vivo in the spinal cord and bladder. MCC950, a selective NLRP3 inhibitor, further validated pathway specificity. No sex differences were detected. Conclusively, DEX-induced hypothermia synergistically suppresses systemic and inflammasome-driven inflammation and promotes reparative immune responses post-SCI. FDA-approved DEX offers a practical, translatable therapy for SCI induced inflammation.
Dietary EPA Promotes Cerebrovascular Remodeling and Impairs Neurovascular Repair After Repetitive Mild Traumatic Brain Injury
Dr. Onder Albayram1
1Medical University of South Carolina, Charleston, United States
Objective: Omega 3 supplements are commonly used after repetitive mild traumatic brain injury (TBI), but it is unclear whether specific components such as eicosapentaenoic acid (EPA) influence long term neurovascular recovery and chronic traumatic encephalopathy (CTE) related vulnerability. We tested whether sustained EPA exposure engages carnitine palmitoyltransferase 1A (CPT1A) mediated fatty acid oxidation in cerebrovascular endothelial cells and aligns with impaired vascular repair.
Methods: Mice were maintained on a fish oil-enriched diet or matched control diet, underwent repetitive, less than mild TBI, and were assessed six months later using lipidomics, whisker-evoked cerebral blood flow (CBF), behavioral testing, transmission electron microscopy, and traumatic cortex transcriptomics. Cerebrovascular endothelial cells were studied under fatty acid-permissive conditions to quantify fatty acid oxidation and regenerative function in the presence of CPT1A inhibition.
Results: Fish oil feeding increased circulating EPA and docosahexaenoic acid, but only EPA accumulated in cortex and was lower in the traumatic region. Fish oil plus injury was associated with reduced stimulus evoked CBF and impaired spatial learning. The traumatic cortex showed increased basement membrane thickness and condensed endothelial nuclei. Transcriptomic analyses highlighted fatty acid metabolism and extracellular matrix remodeling with reduced endothelial proliferation and migration markers. In vitro, EPA increased fatty acid oxidation and suppressed endothelial wound healing and tube formation, and these effects were attenuated by CPT1A inhibition.
Diets Enriched in Omega-3 Polyunsaturated Fatty Acids Alter Brain Cell Membrane Lipid Species and Responses to Brain Injury in Rats
1University Of Pennsylvania, Philadelphia, United States
Studies show omega-3 polyunsaturated fatty acids (ω3 PUFAs) are promising neuroprotective agents that reduce oxidative stress and inflammation while improving cognitive function after traumatic brain injury (TBI). Though critical for neuronal membranes, the specifics of their cellular incorporation and post-TBI impact remain under-explored. Notably, conjugating ω3 PUFAs to lysophosphatidylcholine (LPC) enhances their bioavailability across the blood-brain barrier. In this study, we evaluated the effects of prophylactic dietary administration of free fatty acid docosahexaenoic acid (FFA-DHA), LPC-DHA, and vehicle (PB2) on membrane lipid species and cytokine release. Animals were fed diets daily for 28 days prior to fluid percussion injury (FPI). Twenty-four hours after FPI, both FFA-DHA and LPC-DHA had significant effects on cortical and hippocampal phosphotidylcholine (PC) and phosphotidylethanolamine (PE) lipid species and membrane curvature. In the cortex, FFA-DHA increased free fatty acids but decreased the PE associated with linoleic acid (p≤0.05), while LPC-DHA decreased multiple PEs associated with linoleic acid, palmitic acid, oleic acid, and stearic acid (p≤0.05). Furthermore, LPC-DHA decreased PCs associated with arachidonic acid (p≤0.05). In the hippocampus, FFA-DHA increased only PCs associated with palmitic acid while LPC-DHA decreased only PEs associated with arachidonic acid (p≤0.05). Interestingly, LPC-DHA increased TNF-alpha and IL-6 tissue levels (p≤0.05). Histologically, LPC-DHA reduced hippocampal astrocytosis burden when compared to vehicle diet (p≤0.05), but only trended toward lesser burden in the cortex (p=0.08). Our results suggest that membrane remodeling may play an important role in physiological responses to TBI and that targeted treatment with DHA may offer the potential for prophylactic therapeutic intervention.
Differential Neuropathology in Female versus Male Brain Donors with Chronic Traumatic Brain Injury
1University Of Washington, Seattle, United States, 2Icahn School of Medicine at Mount Sinai, New York City, United States
Traumatic brain injury (TBI) is a growing public health concern and an established risk factor for later neurodegenerative disease. However, how sex influences patterns of exposure, TBI-associated pathology, neuroinflammatory responses, and subsequent neurodegeneration remains poorly understood. Characterizing sex-specific exposures and neuropathologic outcomes may improve risk assessment, prevention strategies, and therapeutic approaches. Brains were obtained from the Pacific Northwest Brain Donor Network and the Mount Sinai Brain Bank. TBI exposure metrics were collected through structured family questionnaires and medical record review. Age-matched male (n=10/group) and female (n=7/group) cohorts younger than 70 years were categorized into control, mild TBI, or severe TBI groups. Mild TBI was defined as head injury with associated symptoms (e.g., headache, slowed processing, or memory loss), while severe TBI included injuries associated with coma, skull fracture, or contusion. All cases underwent comprehensive neuropathologic evaluation for TBI-associated pathology and neurodegenerative disease according to consensus criteria, including assessment for chronic traumatic encephalopathy (CTE). TBI exposures resulted from diverse mechanisms, including falls, motor vehicle collisions, assault, and sports-related injuries. Repeated injuries were more frequently documented in females across both TBI groups, most commonly related to intimate partner violence. Neuropathologic assessment identified CTE and Lewy body pathology exclusively in male TBI cohorts. Females with mild TBI demonstrated higher rates of hippocampal gliosis, while contusions were more frequent in males with severe TBI. These findings highlight sex-related differences in TBI exposure and neuropathologic outcomes, underscoring the need for larger studies to inform prevention and treatment strategies.
Differential Roles of Endothelial and Phagocytic MERTK in Regulating Secondary Injury After Traumatic Brain Injury
Ms. Allison Porter1
1East Carolina University, Greenville, United States
Efferocytosis, the process by which phagocytes eliminate apoptotic debris to resolve inflammation, remains under-researched in the context of traumatic brain injury (TBI). Using the controlled cortical impact (CCI) mouse model, we previously reported that efferocytosis receptor MERTK is expressed on phagocytes (macrophages and microglia) and endothelial cells in injured brain. The current study aims to evaluate the specific role of MERTK in both cell types after trauma. Our group has generated endothelial (Mertkf/fVE-CadherinCreER)- and phagocyte (Mertkf/Cx3cr1CreER)-specific Mertk knock-out (KO) mice and used Mertkf/f and Cx3cr1 CreER mice as wild-type (WT) controls. Western blot analysis showed upregulation of MERTK (2.5-fold) starting 4-dpi and of its ligand, GAS6 (3.6-fold) as early as 1-dpi. Immunohistochemistry revealed GAS6 expression on perivascular cells and phagocyte neighbors. Conditional deletion of Mertk in endothelial cells showed non-significant changes in tissue damage and blood-brain-barrier (BBB) permeability at 3-dpi. However, deletion of Mertk in CX3CR1+ phagocytes significantly increased lesion volume and IgG deposition. A significant increase in apoptotic cell accumulation in the injured cortex was observed in phagocytic-Mertk KO mice. Quantifying the number of phagocytes containing nuclear remnants in their lysosomes revealed more IBA1+ phagocytes upregulating LAMP1, a lysosomal protein, and engulfing DAPI+ puncta in phagocytic-Mertk KO mice than in WT controls. This effect was accompanied by delayed motor function recovery. These findings underscore the critical role of MERTK in phagocyte- (not endothelial cell-) mediated efferocytosis in mitigating acute damage post-TBI.
Differentiating Concussion-Related and Organic Phenotypes of Depression in Former Collegiate Athletes: A CARE-SALTOS Integrated Study-Based Analysis
1Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, United States, 2Department of Neurology, Medical College of Wisconsin, Milwaukee, United States, 3Department of Physical Medicine & Rehabilitation, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States, 4Michigan Concussion Center, University of Michigan, 5Department of Psychiatry, Indiana University School of Medicine
Physical Medicine & Rehabilitation, Uniformed Services University of the Health Sciences, Bethesda, United States, 4Michigan Concussion Center, University of Michigan, Ann Arbor, United States, 5Department of Psychiatry, Indiana University School of Medicine, Indianapolis, United States
Recurrent concussion is generally associated with greater depressive symptom burden across the lifespan. Whether concussion-related depression represents a distinct clinical or biological phenotype remains unclear. In a cohort of 649 former NCAA athletes (Mage=28.5±1.2, 55% male), we examined item-level depressive symptom endorsement on the Patient Health Questionnaire-9 (PHQ-9; n=649), structural brain measures from T1-weighted magnetic resonance imaging (n=600), blood-based proteomic biomarkers (n=420), and their cross-sectional associations with depressive symptom burden, recurrent concussion (0-1 vs. ≥2) and head impact exposure sport participation (no/low vs. high). Recurrent concussion (vs. 0-1 concussion) was associated with 56% greater overall depressive symptom burden (p<.001), whereas participation in high head impact exposure sports was not (p=.26). When stratified by depression symptom severity, participants with subclinical symptoms (PHQ<5) and recurrent concussion endorsed 38% higher overall PHQ-9 scores (p=.006); no differences were observed among those with elevated symptom burden (PHQ-9≥5; p=.24). At the symptom level, recurrent concussion was associated with higher odds of endorsing fatigue (≥several days) among participants with subclinical symptom burden (OR=2.0, p=.003), but not among those with elevated symptoms. Associations of concussion with preselected biomarkers were not moderated by depression symptom severity group. In contrast, symptom severity group moderated the exposure—left medial orbitofrontal cortex thickness association (p=.04), driven by reduced thickness with greater exposure among participants with subclinical depressive symptoms. Collectively, recurrent concussion was associated with differences in select clinical features and structural brain measures only at subclinical levels of depression. Future work should determine whether subclinical symptoms evolve into clinically significant impairment.
Diffuse Axonal Injury Persists in the Posterior Cortex One Month Post-Injury in a Gyrencephalic Model of Blast + Rotational TBI
1Uniformed Services University of the Health Sciences, Bethesda, United States, 2Henry M. Jackson Foundation, Bethesda, United States
Blast-induced traumatic brain injury (TBI) is a prevalent consequence of recent military conflicts. The combined forces of blast overpressure and sudden rotational acceleration on the brain often generate anatomical morphology-dependent pathologies that persist for months post injury. Force transmission through the brain is highly dependent on anatomical morphology, rendering gyrencephalic animal models particularly valuable for replicating human-like injury patterns. Diffuse axonal injury (DAI) signatures, generated by axonal stretching and shearing, are key pathological features of non-penetrating rotational head injury. DAI can manifest as axonal neurofilament hyperphosphorylation and accumulation of axonal beta amyloid precursor protein (β-APP) due to axoplasmic transport dysfunction. Here, we characterize DAI patterns of phosphorylated heavy neurofilament protein (pNfH) and β-APP accumulation in the posterior, medial, and anterior cortex in a ferret model of blast + closed head rotational TBI at one month post injury. In injured animals, gnarled varicosities colabeled with pNfH+/β-APP+ emerge in myelinated neurons at grey/white matter interfaces in the posterior telencephalon. Preliminary data indicate that the intensity of pNfH is elevated in these axonal varicosities by 35.2% (p < 0.05) and 29.7% (p < 0.01) respectively, while the intensity of β-APP is elevated in posterior grey matter by 34% (p < 0.05, n = 2 sham, 2 injured for all). In contrast, pNfH+/β-APP+ signal trends toward a more modest increase in the anterior and medial cortex. These observations reveal morphologically-influenced hotspots of persistent axonal pathology in posterolateral cortical white matter even in the absence of lesions or gross anatomical abnormalities.
Diffusion Abnormalities One Year After Pediatric Mild Traumatic Brain Injury
1Mind Research Network/Lovelace Biomedical and Environmental Research Institute, Albuquerque, United States, 2Department of Emergency Medicine University of New Mexico, Albuquerque, United States, 3Department of Neurology University of New Mexico, Albuquerque, United States, 4Department of Psychiatry and Behavioral Sciences University of New Mexico, Albuquerque, United States, 5Department of Psychology University of New Mexico, Albuquerque, United States
Pediatric “mild” traumatic brain injury (pmTBI) represents a significant clinical challenge given injury incidence and difficulty to asses physiological recovery. Diffusion magnetic resonance imaging (dMRI) has been used to characterize injury extent and recovery, with the majority of studies focused on fractional anisotropy (FA) and mean diffusivity (MD). In contrast, multi-compartmental, geometric models (orientation dispersion index [ODI], intracellular volume fraction [Vic], and isotropic volume fraction [Viso]), may be more sensitive to microstructure abnormalities within the brain, especially when the models are tuned for biologically relevant and tissue-specific properties of diffusion. The current study investigated differences between pmTBI (N=269) and healthy controls (HC; N=231) in these five metrics at ∼7 days (V1), ∼4-months (V2) and ∼1-year (V3) post-injury. Clinical results suggested small but persistent differences across multiple domains, with ∼18.4% of the sample exhibiting persisting symptoms after concussion at 1 year. Imaging results indicated increased FA and decrease in MD in both white and gray matter, persisting up to 1-year post-TBI. Widespread evidence of increased ODI and Vic was also observed in pmTBI across multiple brain regions, whereas, the Viso was increased in WM and decreased in GM. Ongoing analyses are examining the classification accuracy of these various diffusion metrics for predicting group membership. In conclusion, current findings suggest that multiple diffusion abnormalities persist for up to 1-year post-injury, suggesting a prolonged physiological recovery. These findings suggest a potentially longer window of vulnerability following pediatric injury.
DNA Methylation Changes in Response to Mild Traumatic Brain Injury
1UT Houston, Houston, United States
Introduction: Changes in gene expression contribute to the pathophysiology of almost all diseases. Mild traumatic brain injury (mTBI) leads to a spectrum of clinical manifestations, which are likely caused by changes in gene expression. Epigenetic modifications are key regulators of gene expression; we sought to better define DNA methylation changes in response to TBI by comparing the methylation profiles of DNA isolated from circulating cells from mTBI and orthopedic injury patients.
Methods: Whole blood samples were collected from mTBI patients (n=74) and orthopedic controls (n=38) 24 hours after injury. Genomic DNA was extracted and CpG methylation sites were quantified using Infinium MethylationEPIC bead chips, which interrogate the methylation status of >850,000 CpGs. Differentially methylated regions (DMR) were identified by congregating genomically localized CpGs using DMRcate algorithm. Gene Ontology (GO) enrichment analysis was conducted using gene sets derived from DMR-overlapping genes.
Results: 281 DMRs were identified distinguishing mild TBI from orthopedic controls. 166 DMRs (59%) were hypermethylated, and 115 DMRs (41%) were hypomethylated. Hypomethylated DMRs were enriched for processes including tissue remodeling, apoptotic chromosome condensation, membrane invagination, and regulation of monocyte differentiation, with enrichment p-values ranging from 0.01 to 0.001. Hypermethylated DMRs were enriched for processes related to the regulation of anatomical structure, smooth muscle cell migration, sodium ion homeostasis, and metabolic shifts.
Conclusion: After mTBI there are changes in the methylation patterns of several genes, which are likely to alter their expression. Future work will need to elaborate on gene-specific methylation changes and how they may relate to clinical outcomes.
Dose-Dependent Brain Pathology Following Single and Repeated Blast Exposure in Rats
1Department of Neuroscience Karolinska Institutet, Sweden
Blast-induced traumatic brain injury (bTBI) is a major concern among military personnel. Repeated mild bTBI (rmbTBI) may cause persistent cognitive impairments and neurodegeneration, but the underlying pathological changes and injury thresholds remain unclear. In this study, we characterized neuroinflammatory and neurodegenerative changes in vulnerable brain regions following single mild bTBI (mbTBI) and rmbTBI in rats.
Rats were randomized into sham, mbTBI, or rmbTBI groups (n=6/group). Blast exposure was delivered using a metal shock tube with 5 g of pentyl plastic explosive. Animals were secured in a holder shielding the body, exposing only the head with the left side facing the blast.
The hippocampus and cortex were analyzed due to their roles in memory and their vulnerability to TBI. Brain sections were immunostained for glial fibrillary acidic protein (GFAP) to assess gliosis, and TAR DNA-binding protein 43 (TDP-43) as a marker of early neurodegeneration. Integrated density was quantified in cortex and hippocampal subregions Cornu Ammonis (CA) 1, 2 and dentate gyrus (DG) bilaterally.
GFAP expression showed no significant differences, although a non-significant increase was observed following repeated bTBI. In contrast, TDP-43 levels were significantly elevated in the ipsilateral hippocampus of rmbTBI animals compared with sham in CA1 (p=0.0079), CA2 (p=0.0224), and DG (p=0.0397). A contralateral increase was observed in the DG (p=0.0162). However, no significant differences were observed in contralateral CA1, CA2, or cortex.
These findings suggest dose-dependent vulnerability to blast exposure and highlight the importance of assessing long-term pathological consequences following bTBI.
Dynamics of the Pupillary Light Reflex in Collegiate Athletes After Acute Concussion
1Indiana University, Bloomington, United States
Objective: Investigate the pupillary light reflex response in concussed and control athletes at multiple light levels and time points.
Methods: Analysis included 46 collegiate athletes with sport-related concussions and 44 sport-matched controls from Indiana University. Data was collected at 4 timepoints (24 hr post injury, ∼1 wk post recovery, 6 mo, 1 yr). The pupillary light reflex was measured using an SR Research Eyelink 2000. The three light levels were presented in random order and repeated 8 times for a total of 24 trials. The mean, standard deviation, effect size, and AUC for standard measures of pupil dynamics were calculated for each light level. Within subject test-retest reliability was measured using Pearson correlation coefficients within a single study and across time points.
Results: The standard 10 measures of the pupillary light reflex yielded small effect sizes (d = 0.01 - 0.45) and small AUCs (0.47 - 0.62) at the acute time point (24 hr post injury) between the concussed and control athletes. Nine of the 10 pupillary measures yielded moderate to strong test-retest correlation coefficients (r = 0.50 - 0.87) between timepoints 1 and 2. 7 of the 10 pupillary measures had moderate to strong correlation coefficients (r = 0.59 - 0.88) between individual trials within a session.
Conclusion: These results indicate the future is dim for the pupillary light reflex to be useful in acute concussion identification. The correlation results show the pupillary light reflex has surprisingly good test-retest reliability across two different time scales (minute to months).
Early Changes in Hippocampal Network Oscillations Predict Long-Term Seizure Burden and Cognitive Impairments across Distinct Injury Models
1UC Davis Department of Neurological Surgery, Davis, United States, 2UC Davis Department of Molecular Biosciences, Davis, United States
We have previously demonstrated alterations in hippocampal theta oscillations following traumatic brain injury (TBI). Increases in slow-wave delta power are also associated with spontaneous recurrent seizures (SRS). We hypothesize that the ratio of theta to delta power (theta:delta) represents an early electrophysiological biomarker that predicts long-term cognitive impairments following TBI and also the development of SRS subsequent to acute organophosphate intoxication.
Adult male Sprague-Dawley (SD) rats underwent sham (n=13) or lateral fluid percussion TBI (n=40). Cortical screws and depth electrodes were implanted in the dorsal and ventral hippocampus, medial septal nucleus, and prefrontal cortex. Local field potentials and EEG were recorded over the first two weeks following injury, and spatial learning was assessed using the Barnes maze and water maze.
In a separate cohort, adult male and female SD rats were similarly implanted with cortical screws and electrodes and seven days later injected with saline (n=15 males, n=10 females) or the organophosphate diisopropylfluorophosphate (DFP; 4 mg/kg; n=23 males, n=16 females), followed one minute later by atropine-sulfate (2 mg/kg) and pralidoxime (25 mg/kg), and midazolam (0.65 mg/kg) at 40- and 50-minutes. Video-EEG was continuously recorded for 21 days.
The ratio of hippocampal theta:delta power measured one day after injury was significantly and inversely correlated with spatial learning deficits (Barnes maze and water maze) in TBI rats and with SRS burden and spatial learning impairment (Barnes maze) following DFP. Together, these findings suggest that early disruptions to hippocampal oscillations represent a shared biomarker of long-term neurological dysfunction across distinct disease models.
Early Chronic Cognitive and Neurobehavioral Sequalae 5-10 Years Following Repetitive Neurotrauma Exposure in Collegiate Athletes and Military Cadets
1Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, United States, 2Departments of Radiology and Imaging Sciences and Neurology, Indiana University School of Medicine, Indianapolis, United States, 3Indiana Alzheimer’s Disease Research Center, Indianapolis, United States, 4Department of Physical Medicine & Rehabilitation, Uniformed Services University of the Health Sciences, Bethesda, United States, 5Michigan Concussion Center, University of Michigan, Ann Arbor, United States, 6Department of Psychiatry, Indiana University School of Medicine, Indianapolis, United States
Repetitive neurotrauma has been associated with long-term cognitive decline and increased risk for dementia later in life. This study examined associations of recurrent concussion and repetitive head impact (RHI) exposure with cognitive and neurobehavioral function in former athletes/military cadets 5-10 years post-exposure (N=823; Mage=28.7±1.3; 39.6% female). Recurrent concussion and RHI groups included 0, 1, 2, and 3+ and were dichotomized as low and high exposure sport groups, respectively. Outcomes included the Rey Auditory Verbal Learning Test (RAVLT), select subtests of the Delis-Kaplan Executive Function System, WAIS-IV Processing Speed Index, NIH Cognitive Toolbox subtests, and self-report Neuro-QoL Cognitive Function and Emotional and Behavioral Dyscontrol measures. Linear regression models tested associations of exposure with outcomes controlling for estimated baseline intellectual abilities. Compared to those with no concussion history, the 3+ group endorsed significantly more cognitive symptoms (B=-3.85, SE=0.89, p<.001), worse emotional/behavioral difficulties (B=3.43, SE=0.85, p <.001), and performed significantly worse on RAVLT delayed recall (B=-.36, SE=.13, p=.005). The high exposure group performed significantly worse (∼0.5 standard deviation difference) on RAVLT Total Learning (B=-.37, SE=0.08, p<.001), Delayed Recall (B-.34, SE=.09, p<.001), and NIH Picture Sequence Memory (visual memory; B=-3.90, SE=1.29, p =.003) compared to the low exposure group. Individuals with repetitive neurotrauma exhibited subtle cognitive weaknesses compared to their peers, with episodic memory emerging as an area of vulnerability 5-10 years post-exposure. Longitudinal follow-up is ongoing and will be important to determine the long-term trajectory of the observed changes.
Early Field Deployment of the Abbott i-STAT Alinity TBI Whole-Blood Test in MotoAmerica
1The University of Texas at Austin Dell Medical School, Austin, United States, 2MotoAmerica, Irvine, United States
Objectives: To evaluate real-world, trackside deployment of the i-STAT Alinity TBI whole-blood assay (GFAP, UCH-L1) within a professional motorcycle racing series and to assess the clinical utility of ultra-early biomarker measurement, particularly UCH-L1 within one hour of injury, in concussion management.
Methods: During the 2025 MotoAmerica season, riders involved in on-track incidents with suspected concussion underwent standardized clinical assessment. Whole-blood samples were obtained at the point of care and analyzed immediately. Eighteen tests were performed in seventeen riders: fourteen on the day of injury (the majority within the first hour post-incident) and four obtained >12 hours after injury. Biomarkers were considered elevated at GFAP ≥65 pg/mL or UCH-L1 ≥360 pg/mL (FDA-cleared thresholds). Time from injury to blood draw was recorded.
Results:14 of 18 tests (78%) were elevated. UCH-L1 demonstrated particular value in the immediate assessment window, providing objective biochemical evidence when clinical findings were equivocal. Except for 2 riders who had loss of consciousness (witnessed) GFAP was not elevated in same day assays. All riders with elevated biomarkers underwent CT imaging; no intracranial lesions were identified. Four riders with negative biomarker results did not undergo CT and biomarker data were used to exclude concussion.
Conclusion: This represents the first documented real-world integration of rapid whole-blood TBI biomarkers into a professional sport concussion protocol. Immediate biomarker assessment enhanced triage confidence, reduced unnecessary CT utilization, and strengthened objective diagnosis and athlete acceptance, supporting its role in time-critical, field-based concussion management. UCH-L1 was the primary biomarker utilized in the immediate setting.
Early Functional Network Phenotypes Predict Long-term Cognitive Risk After Mild Traumatic Brain Injury
1Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States, 2Department of Neurosurgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States, 3Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States
Objective: Reliable early markers that identify patients at risk for persistent cognitive impairment after TBI remain limited. We aimed to identify reproducible, data-driven phenotypes of large-scale resting-state network organization two weeks post-injury and evaluate their association with cognitive performance and long-term outcomes.
Methods: TRACK-TBI resting-state fMRI data were analyzed in 409 patients (GCS 13-15) two weeks post-injury. Functional connectivity organization was summarized using nodal efficiency, local clustering, and betweenness centrality, averaged within seven canonical networks (Yeo et al., 2011). Ward-linkage hierarchical clustering with bootstrap consensus was used to identify stable phenotypes. Association of these clusters with cognitive performance at 2-weeks and 6-months was tested using age- and sex-adjusted linear regression for RAVLT total and delayed recall, TMT A/B, and WAIS-IV) measures; association with one-year cognitive outcome, defined as impairment (<9th percentile or >91st percentile) or cognitive decline (exceeding the 90% reliable change index on ≥2 of 5 tests) (Schneider et al., 2022), was evaluated using logistic regression. P-values were corrected for false discovery rate.
Results: Three stable network phenotypes emerged, primarily differing in nodal efficiency and centrality. Phenotype membership was associated with one-year cognitive outcome (F=5.12, p=0.025). The most disrupted phenotype demonstrated lower RAVLT performance at 2-weeks (d=0.37, p=0.06) and 6-months post-injury (d=0.48, p=0.03) and had five-fold higher odds of poor one-year cognitive outcome (OR=5.0, 95% CI:1.67–14.9, p=0.035) compared with the least disrupted phenotype.
Conclusion: System-level network phenotyping early after injury identifies injury subgroups with persistent memory deficits and markedly elevated long-term cognitive risk, suggesting a promising imaging marker for early patient stratification.
Early Insomnia Severity Is a Predictor of 12-Month Functional and Quality of Life Outcomes in GCS 14–15 Traumatic Brain Injury
1Department of Neurological Surgery, University of California San Francisco, San Francisco, United States, 2Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital and Trauma Center, San Francisco, United States
Traumatic brain injury patients (TBI) without acute intracranial lesions on computed tomography (CT) imaging often experience persistent symptoms, including sleep disturbance, which negatively impacts functional recovery and quality of life (QOL). The relationship between acute insomnia and long-term outcomes remains undercharacterized. We examined this association in a prospective trauma center cohort.
Participants aged ≥17-years presenting to one Level 1 trauma center with arrival Glasgow Coma Scale (GCS) score 14-15, negative head CT scan within 24-hours, no pre-injury insomnia, who completed 2-week Insomnia Severity Index (ISI, 0-28) and 12-month outcomes (Glasgow Outcome Scale-Extended (GOSE, 1-8) and Quality of Life after Brain Injury-Overall Scale (QoLIBRI-OS, 0-100), were included. Adjusted linear (mean difference (β) [95%CI]) and logistic (adjusted odds ratio (aOR) [95%CI]) regression models examined associations between 2-week ISI, 12-month QoLIBRI-OS and incomplete functional recovery (GOSE < 8).
In 99 subjects aged 39.7±15.3-years, male=68%, White/Caucasian=79%, 20% had clinically significant insomnia at 2-weeks post-injury (ISI≥15). Regression models showed higher 2-week ISI predicted 12-month incomplete functional recovery (aOR=1.15 [1.06-1.26]; p=0.001) and poorer 12-month QoLIBRI-OS (β=−0.84 [−1.34,−0.35]; p=0.001). Baseline psychiatric history (β=−13.08 [−21.54,−4.12]; p=0.003) and older age (β=−0.23 [−0.45,−0.01]; p=0.044) predicted poorer 12-month QoLIBRI-OS.
Two-week insomnia severity predicted 12-month incomplete functional recovery and lower QOL in GCS 14-15, CT-negative TBI patients. Early post-injury insomnia represents a modifiable risk factor in this cohort prone to post-TBI symptoms. Our findings underscore the opportunity for early surveillance for post-TBI insomnia and determining the efficacy of indicated interventions to improve long-term outcomes.
Early Predictors of Long-Term Outcomes in Pediatric “Mild” Traumatic Brain Injury: A Machine Learning Approach
1Mind Research Network, Albuquerque, United States
While most children recover from pediatric “mild” traumatic brain injury (pmTBI), up to one-third experience persisting symptoms after concussion (PSaC) that interfere with school, social, and emotional functioning. Clinicians face the dual challenge of low PSaC rates and non-specific symptom rating even among uninjured peers, making accurate prognosis especially challenging. We used machine learning in a large prospective pmTBI cohort (N=321) to identify indicators of poor recovery at 4 months and 1-year post-injury. Participants completed comprehensive assessments within 11 days of injury that spanned multiple domains including demographics, injury-related factors, child and parent symptom ratings, cognitive tasks, objective performance and symptom provocation on neurosensory tasks. Variable importance scores and 90% confidence intervals from 150 bootstraps were used to identify the best performing assessments within each domain and then integrated into a combined model to assess overall prognostic value. Key findings suggest that retrospective self-report of symptom burden and vulnerability to symptom provocation were the most robust predictors of PSaC at both 4 months and 1-year post-injury, outperforming established risk scores. Other important measures included near point convergence, long-term memory, household size and parental report of child symptom burden. Retrospective symptom burden and acute symptom provocation during simple tasks alongside established risk scores holds promise for improving early risk stratification and guiding individualized care. Additional research is needed to determine how to best integrate these measures into clinical workflows and validate their utility across diverse settings.
Effect of Daily Television and Sleep with Concussion History on Academic Grades: A Youth Risk Behavior Survey Study from 2017-to-2021
Dr. Shawn Eagle1
1University Of Pittsburgh, Pittsburgh, United States
Objectives: We evaluated the association between daily hours of sleep and television, concussion history, and academic performance in a nationally representative sample of U.S. adolescents.
Methods: The YRBS is a nationally representative sample of U.S. adolescents compiled with a 3-stage cluster sampling method. The datasets from 2017, 2019, and 2021 were combined for analysis (n=36,115). Two general linear binomial models were built to evaluate the moderation of sleep and television on SRRC and academic performance controlling for age, gender, race/ethnicity, physical activity and sport participation. Weighted analyses were conducted using the “survey” package in R.
Results: The moderation model for television and SRRC (R2=0.06l; p<0.001) had a significant interaction effect for SRRC and 3+hours of daily television (aOR=0.592, 95% CI: 0.49-0.71, p<0.001). The moderation model for sleep and SRRC (R2=0.08; p<0.001) had a significant interaction effect for SRRC and 8+hours of daily sleep (aOR=1.845, 95% CI: 1.489-2.285, p<0.001). For adolescents with SRRC in the last year, a normal distribution was observed with the lowest probabilities seen in ≤4 hours (7.5%, 95%CI: 6.0-9.2) and 10 or more hours (42.2%, 95%CI: 25.6-60.8); highest probabilities for this population were observed at 7 hours of sleep (73.5%, 95%CI: 68.0-78.3).
Discussion: Reducing daily television to <3 hours/day and sleeping 7-8 hours/day may improve odds of better academic performance in adolescents with SRRC in the past year. A “goldilocks” window of 7-8 hours of daily sleep may be protective against the potentially negative effects of SRRC on academic performance.
Effective Cognitive Rehabilitation for Diffuse Traumatic Brain Injury in Rats Is Associated with Diffusion Restriction Metrics in Limbic Regions
1Neuroscience Graduate Program - University of Michigan, Ann Arbor, United States, 2Physical Medicine and Rehabilitation - University of Michigan, Ann Arbor, United States, 3Concussion Center - University of Michigan, Ann Arbor, United States, 4Veterans Administration Health Care Systems, Ann Arbor, United States
Diffuse traumatic brain injury (TBI) results in axonal injury, neuroinflammation, and synaptic deafferentation that collectively disconnect neural circuits. Despite endogenous repair mechanisms, maladaptive circuit reorganization contributes to persistent cognitive impairment, even in rodents. We developed the spatial exploration Peg Forest cognitive rehabilitation task, which prevents TBI-induced cognitive impairments when initiated subacutely post-injury but is ineffective for deficits persisting chronically. Psychoplastogens, such as ketamine, increase neuroplasticity through widespread spinogenesis and neuritogenesis. We hypothesized that ketamine-induced neuroplasticity, followed by Peg Forest rehabilitation, would restore cognitive performance, with limbic circuit reorganization detectable by MRI diffusivity. Experimentally, female Sprague-Dawley rats received midline fluid percussion injury. One-month post-injury, cognitive performance was assessed on novel object tasks: recognition (NOR), location (NOL), and temporal order (TOR). Animals received a single high dose of ketamine (20mg/kg, IP; n=8) or saline (n=8) one day before ten days of Peg Forest rehabilitation (15 min/day). One-week after rehabilitation, cognitive performance was reassessed, and diffusion tensor MRI was acquired post-mortem. Final discrimination ratios and within-animal cognitive performance differences were compared by multiple linear regression to MRI diffusivity metrics averaged across both hemispheres. Injury-induced cognitive deficits persisted for saline-treated rats (ineffective rehabilitation), and ketamine treatment restored discrimination ratios (effective rehabilitation; NOR=0.002, NOL=0.04, TOR<0.001). Cognitive performance improvement correlated with lower diffusion metrics in the hippocampus (r=-0.68; p=0.0040) and PFC (r=-0.73; p=0.0015). For the first time, psychedelic medicine facilitated effective cognitive rehabilitation, with links to microstructural diffusion states in cognition-relevant brain regions. Imaging may serve as a therapeutic biomarker to track recovery from chronic TBI.
Effects of Falls and Infections on Functional Outcomes in Traumatic Brain Injury Patients During Long-term Acute Care Hospital Rehabilitation
1Walden University, Minneapolis, United States, 2Lakeview Specialty Hospital and Rehab, Waterford, United States
Falls and infections are common complications after traumatic brain injury (TBI) during postacute hospitalization and may impede rehabilitation; however, their impact in long-term acute care hospitals (LTACHs) is not well defined. The objective of this study was to examine associations between in-hospital falls, infections, and functional rehabilitation outcomes among adults with TBI receiving postacute care in an LTACH.
A cross-sectional observational study was conducted among adults with moderate-to-severe TBI admitted for multidisciplinary rehabilitation. Functional outcomes in mobility and activities of daily living (ADLs) were measured using Centers for Medicare & Medicaid Services (CMS) Section GG scores and defined as improvement based on positive change from admission to discharge relative to goal scores. Multivariable logistic regression was used to estimate adjusted associations.
Falls were associated with a 69% reduction in the likelihood of functional improvement (odds ratio [OR]=0.31, 95% confidence interval [CI] 0.10–0.98, p=0.046), and infections with a 62% reduction (OR=0.38, 95% CI 0.15–0.97, p=0.042). No significant interactions with demographic factors were observed.
Falls and infections are independently associated with reduced likelihood of achieving functional rehabilitation goals among adults with TBI in LTACH settings. Preventing these complications is a critical target for improving outcomes in postacute neurorehabilitation.
Effects of Oxycodone Exposure after Mild Traumatic Brain Injury
1University of Miami Miller School of Medicine, Miami, United States
Chronic pain is a common, debilitating symptom after traumatic brain injury (TBI). Oxycodone is often prescribed for chronic pain after TBI, but whether oxycodone impacts recovery from TBI is not well understood. Prior studies have found that oxycodone use after mild TBI (mTBI) increases drug-seeking behavior and neuroinflammation characterized by increased Iba-1 positive microglia. Thus, we hypothesized that mTBI modifies the severity of opioid withdrawal and related emotional and cognitive behaviors after chronic oxycodone use. To test this hypothesis, we characterized affective and cognitive outcomes following mild controlled cortical impact (CCI) and post-injury chronic oxycodone exposure. Male and female C57BL/6J mice received sham or mild CCI surgery followed by escalating oxycodone doses (10–50 mg/kg, s.c.) or saline twice daily for nine days. Behavioral assessments included spontaneous withdrawal testing, open field test, sociability test, tail suspension test, light-dark box test, and fear conditioning.
Mice subjected to mTBI and oxycodone exposure exhibited lower withdrawal severity compared to sham oxycodone-treated mice (interaction of surgery × drug treatment, F(1,89)=7.216, p=0.0086, n=20-26/group). Oxycodone treatment reduced time spent in the center of the open field (main effect of treatment, F(1,75)=12.45, p=0.0007, n=19-20/group) and increased social avoidance (main effect of treatment, F(1,22)=21.37, p=0.0001, n=6-9/group), independent of injury. No significant effects were observed in the tail suspension test, light-dark box, or in associative fear memory or between male and female mice in these measures. These findings indicate that mTBI modulates opioid withdrawal symptoms while oxycodone exposure selectively affects anxiety- and social-related behaviors.
Effects of Peripheral Injury and Surgery on Traumatic Brain Injury Outcomes in Rats
1Medical College of Wisconsin, Milwaukee, WI, United States
Introduction: Extracranial surgery is associated with worse functional and cognitive outcomes in humans early after TBI, but only in participants with decreased alertness/responsiveness (GCS 3-12) or with radiographic abnormalities on CT scan with preserved GCS at index admission. This observational data cannot establish causality. We utilized a reverse translational animal model to control confounding variables that cannot be manipulated clinically.
Hypothesis: Peripheral injury or surgery is a secondary insult after TBI that leads to worse outcomes when compared to TBI or peripheral injury alone.
Methods: Male Sprague-Dawley rats (n=40) were randomized to exposure to validated models of TBI (rotational injury) and peripheral injury (stabilized femur fracture) in four groups (n=5-17): Sham, Sham+fracture, TBI, TBI+fracture. Neurological Severity Score (NSS-R) was assessed on days 1, 4, 7, and 14 after TBI.
Results: TBI groups had significantly worse NSS-R scores than sham groups on post-TBI day 1 (7.0±2.9 vs. 0.7±0.7, p<0.0001), day 4 (3.4±2.3 vs. 0.6±0.7, p=0.0035), and day 7 (2.6± 1.1 vs. 0.3±0.5, p=0.0307). There was a trend towards worse function between Sham+fracture versus sham groups. No significant differences were detected between TBI and TBI+fracture groups.
Conclusions: Univariate analysis did not support the hypothesis that a peripheral injury or surgery worsened TBI outcomes. Null results may indicate confounds (sleep disruption, food restriction) or that the rotational injury may not reflect the TBI groups vulnerable in humans. Future directions include covariate analysis accounting for blood-based biomarkers and other clinical assessments to determine if peripheral injury worsens neurological outcomes in this rat TBI model.
Effects of Pre-existing Angiotensin II–Induced Hypertension on Acute TBI-Induced Neuropathology in Mice
1University of Kentucky, Lexington, United States
Traumatic brain injury (TBI) is a leading cause of morbidity and mortality, commonly associated with neuroinflammation, blood-brain barrier (BBB) disruption, and neuronal loss. Hypertension, an independent risk factor for cerebrovascular dysfunction, is prevalent among TBI patients, yet its influence on post-traumatic neuropathology remains unclear. To evaluate the effects of premorbid systemic hypertension, adult male C57BL/6 mice (n=8/group) were implanted 3 weeks before injury with a 4-week mini-osmotic pump to deliver saline or angiotensin II (Ang-II; 1000 ng/kg/min) to elevate systolic blood pressure (≥160 mmHg). To isolate pre-injury effects of Ang-II infusion, one group had their Ang-II pump removed one day before injury, normalizing blood pressure at injury. Mice were euthanized 1 week after controlled cortical impact (CCI, n=32) or sham injury (n=16) for histological analyses.
Ang-II infusion in sham-injured mice led to a small, but significant, increase in cortical microbleeds (Prussian blue staining) and a trend towards increased thalamic and hippocampal neurodegeneration (Fluorojade C+ cells). In injured mice, hypertension limited to the pre-injury period led to increased cortical contusion volume and greater injury-induced hippocampal microbleeds, along with a trend towards increased astrogliosis. However, when Ang-II administration was continued through 1-week postinjury, most of these effects were not observed; rather, an increase in IgG extravasation was noted in the ipsilateral corpus callosum. These results suggest that pre-injury hypertension may modestly amplify CCI-induced cortical tissue damage and astrogliosis, but post-injury hypertension elicited by Ang-II infusion acts to partially mitigate these effects.
Effects of the Probiotic Limosilactobacillus reuteri on Behavioral Outcomes Following Frontal TBI in Rats
1The Ohio State University, Columbus, United States, 2Nationwide Children's Hospital, Columbus, United States
Traumatic Brain Injury (TBI) contributes to chronic psychiatric and cognitive impairments, including impulsivity and risky decision-making. TBI also causes gut dysbiosis, or an imbalance of microorganisms within the gut microbiome. Given the gut microbiome’s role in modulating neurotransmitter production and metabolism, alterations in microbial composition following TBI may contribute to behavioral deficits through disrupted signaling along the gut-brain axis.
The current study assessed whether targeting gut dysbiosis with the probiotic dietary supplement, Limosilactobacillus reuteri (L.reuteri), could mitigate behavioral deficits following TBI. Rats were food restricted on standard chow and administered L.reuteri (125µl of 1x107 CFU/mL) in strawberry Jell-O tablets (or vehicle) twice/day six weeks prior to and 4 weeks after receiving a moderate-severe frontal controlled cortical impact injury (or sham surgery). Rats were assessed on the Rodent Gambling Task (RGT; risky decision making), the elevated plus maze (EPM; anxiety-like behavior), the forced swim test (FST; depressive-like behavior), and the Morris water maze (MWM; learning and memory). Fecal samples were collected prior to injury and at multiple post-injury time points for DNA extraction and 16S rRNA microbiome sequencing.
During pre-surgical training on the RGT, L.reuteri increased preference for the optimal choice over time. Moderate-severe TBI impaired behavior on the MWM, EPM, and RGT, but L.reuteri did not significantly alter these outcomes. L. reuteri decreased time spent immobile on the FST. Results are ongoing but suggest that modulating the gut microbiome may be a promising therapeutic strategy for improving select TBI-related behavioral deficits.
Effects of Transcranial Magnetic Stimulation on Sleep and Astrogliosis Following Repetitive Traumatic Brain Injury
Ms. Nija White1
1Florida International University, Miami, United States
In the central nervous system adenosine levels are integral to sleep regulation and efficiency. Adenosine accumulation promotes sleep and inhibits arousal, and adenosine clearance triggers wakefulness. Adenosine kinase (ADK) is an enzyme that regulates adenosine levels, through the conversion of adenosine to adenosine monophosphate (AMP). Following a traumatic brain injury (TBI), ADK activity is upregulated, leading to increased sleep disruption, neuroinflammation, and astrogliosis. This pathology creates a prime environment for neurodegeneration and cognitive decline. Transcranial magnetic stimulation (TMS) is a non-invasive neuromodulation technique, that directly impacts cortical excitability and improves cognitive function. This work examines the impact of repetitive transcranial magnetic stimulation on sleep efficiency and astrogliosis through adenosine metabolism following diffused rTBI and induced chronic sleep disruption.
We induced chronic sleep disruption for 14 days followed by repetitive diffuse TBI in 12–16-week-old C57BL/6J mice (SHAM, TBI, TBI+TMS). TMS treatment started on day 1 post-TBI and lasted 2 weeks. After the final session, epidural electrodes and nuchal muscle leads were implanted for 2 weeks of continuous monitoring. Automated sleep analysis was performed in NeuroScore to assess sleep efficiency. Blood collection and plasma separation was conducted at 4 timepoints; prior to TBI, 14, 28, and 60 days post injury.
Two-way ANOVA of preliminary data showed significant differences in GFAP concentrations across groups and timepoints. Preliminary sleep analysis revealed that TBI increases the number of NREM bouts, reflecting greater sleep fragmentation and reduced sleep efficiency. However, TMS treatment appeared to reduce fragmentation and promote more stable sleep patterns.
Electrode Density Determines Detection Sensitivity for Cortical Spreading Depolarizations in Acute Brain Injury
1Hennepin Healthcare Research Institute, Minneapolis, United States
Objective: To quantify how electrode number and placement strategy influence detection of cortical spreading depolarizations (CSD) in patients with acute brain injury.
Methods: Cortical spreading depolarizations were identified from 32-contact subdural electrocorticography recordings in six patients using semi-automated detection with manual validation. Reduced-contact monitoring configurations were simulated using three approaches: random electrode sampling, frequency-based ranking according to event participation, and greedy selection maximizing marginal event capture. For each configuration, we calculated the probability of detecting at least one CSD event and the proportion of total events captured.
Results: Single-electrode sampling captured a small fraction of total events, indicating limited ability to estimate event burden. Detection probability increased nonlinearly with electrode count. Random electrode sampling required an average of 21 electrodes to achieve event-capture fractions approaching 90% in spatially diffuse cases. In contrast, frequency-guided and greedy strategies improved capture efficiency when events were spatially clustered, requiring only 12 and 7 electrodes on average, respectively. Notably, substantially fewer electrodes were required to determine the presence of cortical spreading depolarizations than to accurately quantify total event burden.
Conclusions: Electrode density critically determines monitoring performance. Limited-contact systems may be sufficient to detect whether spreading depolarizations are occurring, but accurate burden quantification generally requires higher-density coverage or optimized electrode placement. These findings provide a quantitative framework for designing scalable monitoring strategies in acute neurotrauma.
Elevated Intracranial Pressure Alters Astrocyte-Related Protein Expression, Localization, and Solute Clearance Following Traumatic Brain Injury in Rats
1Virginia Commonwealth University, Richmond, United States
Secondary intracranial pressure (ICP) elevation exceeding 20mmHg exacerbates the negative outcomes caused by traumatic brain injury (TBI). TBI induces edema linked to changes in water movement, blood brain barrier permeability, and impaired solute clearance/glymphatic dysfunction, which are intensified by ICP elevation. Therapy for TBI-induced ICP elevation centers around avoiding ischemic hypoperfusion by redirecting water from the brain via hypertonic solutions, however, a sub-population is unresponsive to treatment. Therefore, investigating potential cellular and molecular mechanisms involved in mediating water movement within the brain following TBI and secondary ICP elevations could lead to new therapeutic targets. Additionally, there is debate regarding the clinical cutoff of 20mmHg for intervention, therefore, investigating secondary ICP elevation induced changes across varying ICP levels may provide further insight into the mechanisms of damage associated with decreased mortality and morbidity. Astrocytes are the primary regulators of water movement and blood-brain barrier maintenance in the brain. To evaluate the TBI-induced changes in astrocyte-mediated water movement at various ICP levels, adult male Sprague-Dawley rats sustained a central fluid percussion injury paired with either ICP monitoring or manual ICP elevation via intracerebroventricular infusion to 15mmHg, 20mmHg, or 25mmHg from 15min to 1hr post-injury. Evaluations were done at 4-week post-injury to investigate expression of astrocytic swelling related channels, potential shifts of aquaporin-4 (AQP4) localization, and long-term solute clearance impairment. Our results indicated TBI and ICP-mediated astrocytic alterations, though additional analyses are needed to clarify AQP4 and glymphatic involvement.
This work was funded by NINDS R01NS096143.
Elucidation of Progressive Transcriptional Regulation within Serotonin Neurons Following Mild Traumatic Brain Injury
1University of Cincinnati, James L Winkle College of Pharmacy, Division of Pharmaceutical Sciences, Cincinnati, United States, 2University of Cincinnati, College of Medicine, Neuroscience Graduate Program, Cincinnati, United States
Mild traumatic brain injury (mTBI) affects millions annually within the United States alone. mTBI commonly results in comorbidities such as anxiety, depression, sleep disturbances and intractable headache, all classically associated with serotonin (5-HT) neurotransmission. 5-HT neurons reside in the raphe nucleus (RN) and project to brain regions controlling behavior, emotions, and physiological functions. Currently, there are no available pharmacotherapies specifically for mTBI.
We hypothesize that elucidation of cell-specific mTBI-induced 5-HT neuron adaptations will allow for informed drug discovery efforts. To investigate this, adult C57Bl/6 mice underwent blast-/acceleration-deceleration-induced mTBI or sham procedures. 3-, 10-, or 30-days post-injury (dpi), RN tissue was excised for single-nucleus RNA sequencing (snRNA-seq). Using Seurat in R for UMAP generation and differential expression analyses, 5-HT neuron populations were identified by NeuN and Tph2 co-expression. Differential expression analysis at 3, 10 and 30 dpi, revealed 142, 182 and 19 differentially expressed genes (DEGs) identified specifically within 5-HT neurons, respectively (adjusted P value ≤ 0.05). STRING analysis revealed 5-HT neuron specific DEGs are associated with cell & plasma membrane adhesion at 3-dpi, transitioning to synaptic signaling and synaptic transmission alterations at 10-dpi. Waddington optimal-transport analysis of snRNA-seq data revealed that specific, unique subpopulations of 5-HT neurons are preferentially altered by injury over time. Studies are the first to provide evidence of transitional phenotypes within specific subpopulations of 5-HT neurons with a high level of temporal resolution following a single mTBI. Future studies are aimed at elucidating injury-elicited cell-specific adaptations within established, identifiable 5-HT neuron subpopulations of the RN.
Emergency Department Clinician Perspectives on Giving Effective Discharge Education for Concussion from the EDucate Study
1Medical College of Wisconsin, Milwaukee, United States, 2The Ohio State University, Columbus, United States, 3University of Michigan, Ann Arbor, United States, 4University of Kentucky, Lexington, United States
Patients who present to emergency departments (EDs) may neither be formally diagnosed with concussion nor receive education about post-acute management. This abstract reports on the methods and findings of a federally funded qualitative study investigating themes of clinician perspectives regarding determinants of giving effective concussion discharge education. We developed a semi-structured interview guide aligned with the Integrated-Promoting Action on Research Implementation in Health Services model to understand clinician perspectives on clinical assessment, workflow, and decision making related to concussion, current education and discharge practices for patients with concussion, and barriers and facilitators for improving education. Utilizing a deductive rapid qualitative analysis method (Stanford Lightning Report), we generated a concise report for partners that synthesized themes. Interview and qualitative survey feedback was integrated from 95 participants (physicians, advanced practice providers, nurses, residents) into a final lightning report. The findings were as follows: 1) Positives included consistent understanding of key concussion principles, multidisciplinary collaboration during discharge, involvement of support persons, public awareness of concussion; 2) Challenges included insufficient time, knowledge gaps leading to diagnostic variability, limited review of handouts with patients, ingrained practice patterns resistant to change, and ineffective follow-up referral pathways; 3) Insights and Recommendations including clinicians preferring “concussion” over mTBI diagnoses, empowering nurses for discharge education, implementing post-discharge follow-up calls, and integrating scoring tools for mTBI assessment. The study identifies targets for clinical intervention and illustrates the use of rapid qualitative analysis methodology to provide timely qualitative data to stakeholders for implementation science studies.
Engineered Mesenchymal Stem Cell Transplantation for Reduction of Acute Inflammation after Spinal Cord Injury
1Rush University, Chicago, United States
After a traumatic spinal cord injury (SCI) there is initially a loss of nervous tissue followed by secondary damage, driven by chronic inflammation, which is not reversible. Mesenchymal stem cells (MSC) are multipotent stem cells that have been shown to improve multiple SCI outcomes following transplantation, notably via their anti-inflammatory effects and immunomodulation. However, unlike other tissues, MSCs do not home to sites of spinal cord injury. This is due to mammalian MSCs lacking E-selectin binding activity, because their sialylated (sLeX) motif in CD44 lacks fucose, which is crucial for cell trafficking and homing. To make MSCs capable of adhering to the endothelial barrier and being trafficked to injury sites, our team has generated Hematopoietic cell E-/L-Selectin ligand (HCELL) CD44 glycoform in MSCs by exofucosylation. We administered HCELL-MSCs directly within the vasculature to deliver MSCs to the SCI epicenter (via tail vein injection) to female Sprague-Dawley rats after they received a moderate SCI (at vertebral T9). We compared the effect of HCELL-MSCs to regular MSC transplantations using behavioral measures as well as flow analysis and immunohistological outcomes.
Past experiments have shown that MSCs reduce the expression of immune cells and promote M2 polarization. After HCELL-MSC transplantation, immune cells within the spinal cord exhibited similar levels to rats that received transplantations of normal [nonfucosylated] MSCs within the cord, but with a significant shift in anti-inflammatory (M2) macrophage polarization in the rats that were transplanted with HCELL-MSCs. Additionally, HCELL-MSCs offer a minimally invasive method of administration, enhancing their translatability.
Engineering ARC nanocapsids for systemic RNA delivery targeting post-traumatic brain
1Sanders-Brown Center on Aging, University of Kentucky, Lexington, United States, 2Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, United States, 3Pathology & Laboratory Medicine, University of Kentucky, Lexington, United States, 4Neuroscience, University of Kentucky, Lexington, United States
Traumatic brain injury (TBI) triggers a complex pathophysiological cascade that progresses over hours to days after the initial insult. Neurons are especially susceptible to both primary mechanical injury and subsequent secondary processes, including oxidative stress, excitotoxicity, and neuroinflammation, all of which contribute to poor functional outcomes. Despite extensive research, effective strategies to mitigate secondary injury and restore neuronal function remain limited. A major barrier to therapeutic success is the blood–brain barrier (BBB), a highly selective physiological interface that protects the brain from pathogens and toxins but also restricts systemic delivery of most therapeutic molecules.
Here, we report the development of BIONARC (Blood–brain barrier Infiltrating Optimized Neuron-targeting ARC Capsids), a versatile nanocarrier platform capable of systemically delivering RNA therapeutics to the injured brain. BIONARC leverages the self-assembling properties of neuronal Arc protein, incorporates the BBB-penetrating rabies virus glycoprotein peptide (RVG29), and is engineered to encapsulate mRNA and microRNA cargos. Plasmid constructs were designed to co-express the RVG29 peptide, Arc proteins, and a StrepII affinity tag protein purification. The polypeptides were then assembled and loaded with mRNAs (EGFP, SOD2) or microRNA (miR-223).
BIONARC nanocarriers were successfully produced, and the resulting capsid-like structures were confirmed using nanoparticle tracking analysis and transmission electron microscopy. In vitro studies further demonstrated efficient packaging of RNA cargos and release and expression within recipient cells. Together, these findings establish BIONARC as a novel, functional nanocarrier system capable of delivering RNA therapeutics to target cells and represent a promising platform for treating TBI-related neuronal pathology.
Environmental Drivers of Rod Microglia Morphology in the Brain-Injured Cortex
1University of Michigan, Ann Arbor, United States
Activated microglia are central architects of pathophysiology and recovery after traumatic brain injury (TBI), coordinating inflammatory, synaptic, and extracellular remodeling. Among these varied roles, microglia adopt diverse morphologies. Yet structure–function relationships remain incompletely defined; microglia morphologies generate overlapping gene expression profiles across diseases.
Rod microglia represent a unique activated morphology with functions left undetermined. Importantly, rod microglia emerge in injured—not healthy or necrotic—tissue, positioning them as gatekeepers between progressive damage and repair after TBI. They are defined by elongated, spiraling cell bodies aligned end-to-end in linear trains within the cortex, enabling genetic interrogation of function from structure – yet revealing no shared gene expression profile from transcriptomics. Among activated microglia, we propose that rod morphology arises from environmental drivers: targeted associations with linear elements of injured tissue (e.g., axons).
Using fluid percussion injury to induce rod microglia in rat cortex, we performed dual-label immunohistochemistry to link rod microglia (IBA-1) with environmental markers. 25 putative targets were selected from published RNAseq datasets of rod-enriched microglia in orthogonal disease models (mouse amyotrophic lateral sclerosis, human Alzheimer’s disease) related to cellular architecture, extracellular remodeling, and tissue stress responses. Fluorescence microscopy revealed that rod microglia coil around ferritin-positive neuronal processes rather than align, forming an intimate interface at oxidatively stressed sites. Thus, rod microglia may envelope injured cellular elements. Also, rod microglia were MMP9-positive and colocalized with aggrecan, findings consistent with extracellular remodeling. Encouraging results motivate studies of rod microglia within their surrounding environment, where identifying environmental drivers clarifies functional roles and therapeutic potential.
Epidemiology of All-Terrain Vehicle Accidents in Children Younger Than 11 Years Old Seen at a Trauma Center in West Texas
Mr. Nicolas Fandrich1,
1Texas Tech Hsc, Department of Pediatrics, Lubbock, United States
This study examines all-terrain vehicle (ATV)- related injuries seen at University Medical Center Children’s Hospital (UMCCH) in Lubbock, TX over a five-year period (January 2020-December 2024), with a focus on identifying differences in head injury rates and injury severity across age groups. We hypothesize that younger children, 0-10 years old (y), will have a higher incidence of head injury based on anatomical differences (head occupying a larger fraction of the body surface area) when compared to older children.
In this retrospective cohort study of a total of 194 cases, we analyzed injury characteristics including Injury Severity Score (ISS), driver vs. passenger status, helmet and protective gear use, and head trauma incidence. Head injuries were more common in younger children (0–10), affecting 53% of the group, compared to 32% of older children (11+), despite similar rates of helmet use.
These findings suggest that younger pediatric populations are particularly vulnerable to head trauma in ATV accidents and may benefit from targeted safety interventions.
Evoked Compound Action Potentials as a Marker of Motor Activity During Spinal Cord Stimulation in Spinal Cord Injury
1University Of Minnesota, Minneapolis, United States, 2Hennepin Healthcare Research Institute, Minneapolis, United States, 3University of Miami, Miami, United States
Spinal Cord Stimulation (SCS) is a promising treatment for Spinal Cord Injury (SCI). Prior studies have shown that motor responses change with stimulation frequency and amplitude. Recent advances demonstrate that Evoked Compound Action Potentials (ECAPs) can serve as a physiologic biomarker to titrate stimulation intensity in SCS for chronic pain. ECAPs have not been examined in SCI and provide a novel method to gain mechanistic insight and clinical translation of SCS. We hypothesize that ECAP features can serve as a biomarker of motor threshold.
We intraoperatively recorded ECAPs and electromyography (EMG) in individuals receiving SCS for SCI while systematically varying stimulation frequency and stimulation amplitude. EMG signals were analyzed to identify motor thresholds and characterize motor recruitment patterns. ECAPs were cleaned for feature extraction. Statistical analyses were performed using a generalized linear model (GLM) with stimulation amplitude and frequency as predictors.
Both stimulation amplitude and frequency significantly influenced ECAP morphology and EMG activity. Increasing stimulation frequency reduced ECAP amplitude and area under the curve at equivalent amplitudes (p-value < 0.005). EMG recordings showed fewer muscles responding and higher motor thresholds with increasing frequency, indicating frequency-dependent attenuation of motor recruitment (p-value < 0.001).
Stimulation amplitude and frequency jointly shape ECAP and EMG responses during SCS for spinal cord injury. ECAP features emerge as quantitative biomarkers linking stimulation waveform energy and neural synchrony to downstream motor recruitment, providing a mechanistic framework for optimizing frequency-dependent SCS paradigms and improving motor restoration outcomes in SCI.
Examining Regionally Specified Spinal Neural Progenitor Cells and Targeted Forelimb Rehabilitation in Enhancing Recovery After Bilateral Compressive-Contusive Cervical Cord Injury
1Institute of Medical Science, University of Toronto, Toronto, Canada, 2Division of Genetics and Development, Krembil Brain Institute, University Health Network, Toronto, Canada, 3Xuanwu Hospital of Capital Medical University, Beijing, China, 4Department of Anatomy, University of Toronto, Toronto, Canada, 5Division of Neurosurgery and Spine Program, Department of Surgery, University of Toronto, Toronto, Canada
Transplantation of regionally specified spinal cord neural progenitor cells (spNPCs) represents a novel approach to promote enhanced graft integration, neural repair, and functional recovery following cervical spinal cord injury (SCI). In the study, we aimed to examine the therapeutic effect of combining spNPC transplantation with forelimb rehabilitation in SCI. Following a unique and clinically relevant bilateral C6/C7 clip compression-contusion SCI (n=52), female immunodeficient Rowett Nude rats were randomly assigned to injury, rehabilitation, spNPC transplantation, and rehabilitation + spNPC transplantation groups (n=8-15/group). Control animals (n=9) received a laminectomy surgery. 4-7 days after spNPC transplantation, 8 weeks of forelimb rehabilitation was conducted and involved two pellet reaching tasks that enabled continuous engagement. Forelimb grip strength, Montoya staircase test (skilled reaching), inclined plane (trunk stability), and Von Frey (mechanical sensitivity) were conducted biweekly for 15 weeks post-SCI to examine behavioural outcomes. CatWalk gait analysis (locomotion) and electrophysiological assessment of the corticospinal tract (n=8-12/group) were completed at endpoint. Perilesional scar components (collagen IV and chondroitin sulfate proteoglycans), excitatory synapses, and spNPC differentiation were assessed by immunohistochemistry and confocal imaging (n=4-6/group). The combined treatment enabled better performance at the Montoya staircase test (p<0.05; weeks 3-13) and grip strength test (p<0.05; weeks 7-9), demonstrating improved recovery of forelimb function. The combined treatment also improved electrophysiological outcomes, specifically the stimulation threshold, latency, and total muscle response (p<0.05). The observed enhancement in functional and electrophysiological recovery indicates the importance of regional specification of cell therapies and targeted rehabilitation strategies as exciting approaches to inform future therapeutic strategies.
Examining the Influence of Neurotrauma History and Obesity on Cerebral Blood Flow in Former NFL Players at Late Life
1Clement J. Zablocki VA Medical Center, Milwaukee, United States, 2Department of Neurosurgery and Neurology, Medical College of Wisconsin, Milwaukee, USA, 3Departments of Emergency Medicine and Pediatrics, Harvard Medical School, Boston, USA, 4Division of Emergency Medicine, Boston Children’s Hospital, Boston, USA, 5Department of Neurological Sciences, Rush Alzheimer’s Disease Center, Chicago, USA, 6University of Missouri Kansas City, Kansas City, USA, 7University Orthopedics Center Concussion Clinic, State College, USA, 8Department of Kinesiology, Michigan State University, East Lansing, USA, 9The Micheli Center for Sports Injury Prevention, Boston, USA
Studies have reported associations between repetitive neurotrauma and long-term neurological outcomes. The potential contribution of cerebrovascular health has been understudied in older former athletes despite its importance in neurological function. This study examined associations between cumulative neurotrauma and obesity with cerebral blood flow (CBF) in a subsample (N=58) of former National Football League players (Mage=60.66±6.16 years). Participants underwent magnetic resonance imaging with pseudo-continuous arterial spin labeling to quantify CBF. A priori CBF regions of interest (ROIs) were total white and gray matter, and bilateral medial temporal lobe regions including the hippocampus, amygdala, parahippocampal and entorhinal cortex. Neurotrauma metrics included concussion history (low[0-3], medium[4-12], high[13+]) and the Cumulative Head Impact Index (CHII) as a measure of repetitive head impact exposure (RHI). Obesity was quantified as the android/gynoid fat (A/G) ratio as measured by dual-energy x-ray absorptiometry. Associations between neurotrauma history with ROI CBF were largely not observed (ps>.05), with the exception of lower parahippocampal CBF (p=.014, np2=.11) in those with greater RHI. Higher A/G ratio was significantly associated with lower CBF in all ROIs (ps<.05; np2 =.20), with the strongest observed in the hippocampus (p<.001; np2 =.20), amygdala (p<.001; np2 =.20), and total grey matter (p=.005; np2 =.14). Findings suggest limited associations between repetitive head impact exposure and long-term CBF, though specific ROIs (i.e., parahippocampal gyrus) may represent regions of vulnerability independent of systemic cardiometabolic health. Obesity was strongly associated with CBF diffusely and represents a critical factor for inclusion of cerebrovascular and neurological health in older former contact sport athletes.
Examining the Relationship Between Hypercapnea and ICP in Critically Ill Patients after TBI
1Brain and Spinal Injury Center (BASIC), Zuckerberg San Francisco General Hospital and Trauma Center, San Francisco, United States, 2Weill Institute for Neurosciences, University of California, San Francisco (UCSF), San Francisco, United States, 3Department of Neurosurgery, University of California, San Francisco, San Francisco, United States, 4San Francisco Veterans Affairs Healthcare System, 5Department of Neurology, University of California, San Francisco, San Francisco, United States
Though current guidelines suggest inducing hypocapnia to lower intracranial pressure (ICP) in traumatic brain injury (TBI) patients, it is well established that hypocapnia can cause cerebral ischemia. In contrast, there is limited evidence regarding the safety of hypercapnia in TBI patients and its relationship to ICP.
Our objective was to explore the relationship between maximum blood carbon dioxide (PaCO2) levels and ICP (PaCO2*ICP). Our secondary objective was to understand if PaCO2*ICP is altered in cases where patients developed the secondary complication of acute respiratory distress syndrome (ARDS), which can commonly occur in TBI patients.
Eighty-seven intubated patients with TBI and intracranial monitoring, grouped by ARDS status, were included. In the ARDS group there were 16 patients (15 male, 1 female) with median age 44.0 years (± 1.7 SEM) and median GCS 7 at admission (IQR 3-12). In the non-ARDS group there were 71 patients (56 male, 15 female) with median age 58.8 years (± 1.1 SEM) and median GCS 8 at admission (IQR 3-12).
Using linear mixed models, we found that ICP was not directly associated with PaCO2 (β=0.10, p=0.706). Mean PaCO2 levels were significantly elevated in ARDS compared to non-ARDS group (40.2 ± 0.6, 37.0 ± 0.3 SEM, p<0.05), but ARDS did not alter the relationship between PaCO2*ICP (β=0.26, p=0.324).
These results indicate PaCO2*ICP, if one does exist, is likely non-linear. Further work will explore additional physiological variables, as well as non-linear modeling approaches to better characterize PaCO2*ICP dynamics in TBI patients.
Extending a Repetitive Mild Traumatic Brain Injury Model to Female Rats: Behavioral Characterization and Implications for Chronic Pain Mechanisms
1University of Puerto Rico at Cayey, Cayey, Puerto Rico, 2University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico
Chronic pain is a frequent and debilitating consequence of mild traumatic brain injury (mTBI), affecting over 60% of patients. Sex differences in mTBI outcomes have received growing attention, as females often report greater prevalence and severity of post-traumatic symptoms, including chronic pain. However, preclinical studies have historically underrepresented females, limiting translational relevance. To address this gap, we employed a repetitive closed head injury (rCHI) weight-drop model in female rats to further characterize mTBI. Injury severity was evaluated by measuring time to wake, right, and ambulate, with no significant differences observed between Sham and rCHI groups (p=0.1399, p=0.0807, p=0.3333), supporting classification as mild injury and indicating no loss of consciousness. Locomotor activity was assessed using the open field test at 4, 8, and 16 days post-injury, revealing no differences in total distance traveled or time spent in the center between groups. Given the association between mTBI and anxiety, anxiety-like behavior was assessed using the elevated plus maze at 48 days post-injury. No significant differences were observed in time spent in open arms or number of open arm entries, suggesting absence of anxiety-like behavior. Ongoing studies are examining pain-related behaviors and NLRP3-associated proinflammatory cytokine expression in brain regions involved in pain processing. Overall, this study extends our rCHI model to females, demonstrating key features of mild injury without confounding locomotor or anxiety-related effects, and supporting investigation of sex-specific mechanisms underlying chronic pain following mTBI.
External Ventricular Drain Versus Intraparenchymal Pressure Monitor in Traumatic Brain Injury: An Updated Meta-analysis
Mr. Lucas Woehl1, Ms. Isabela Bini1, Mr. Pedro Denardi1, Mr. Emanuel Pereira1,
1Planalto Catarinense University of Medicine, Lages, Brazil, 2Houston Methodist Hospital, Houston, United States, 3University of Sao Paulo, Sao Paulo, Brazil
Objective: To compare the efficacy of external ventricular drains (EVDs) versus intraparenchymal monitors (IPMs) for intracranial pressure monitoring (ICPm) in traumatic brain injury (TBI).
Methods: We systematically searched PubMed, Embase, Web of Science, and the Cochrane Library for studies including patients with TBI undergoing ICPm with EVD or IPM. Outcomes were functional outcome (Glasgow Outcome Scale [GOS] or GOS–Extended [GOS-E]), hospital length of stay (LOS), intensive care unit (ICU) LOS, last follow-up mortality, and 6-month mortality. Subgroup analyses were performed for studies including only severe TBI. Meta-analyses used risk ratios (RR) and mean differences (MD) with random-effects models in R (v4.4.2).
Results: From 2657 screened records, nine studies comprising 7,344 patients were included (3,453 EVD and 3891 IPM). The weighted mean age was 46.3 versus 42.8 years in the EVD and IPM groups. ICU LOS was significantly longer with EVD overall (MD 0.88, 95%CI 0.24–1.51; p=0.007; I2=35.9%) and in the severe TBI subgroup (MD 1.90, 95%CI 0.61–3.19]; p=0.004; I2=61.5%). Last follow-up mortality also favored IPM in the severe TBI subgroup (RR 1.05, 95%CI 0.76–1.43; p=0.51; I2= 0.1%). Functional outcome (p=0.37), hospital LOS (p=0.85), and 6-month mortality (p=0.35) did not differ between groups.
Conclusion: Despite overall similar outcomes, IPM may reduce long-term mortality and shorten ICU LOS in severe TBI.
Factors Associated with Spinal Cord Injury Among Adults with Vertebral Fractures: A National Trauma Data Bank Analysis
1Suny Downstate Health Sciences University, Brooklyn, United States, 2Icahn School of Medicine at Mount Sinai, New York, United States
Objective: Identifying vertebral fracture patients at risk for spinal cord injury (SCI) is critical for early monitoring, yet national studies evaluating potential factors remain limited. This study examined factors associated with SCI among adults with vertebral fractures using a national trauma registry.
Methods: Adults (≥18 years) admitted with cervical, thoracic, and/or lumbar vertebral fractures in the National Trauma Data Bank from 2019–2021 were analyzed retrospectively. Demographics, injury characteristics, complications, and hospital course data were collected. A multivariable logistic regression model was used to identify factors associated with SCI presence, reported as adjusted odds ratios (aOR) with 95% confidence intervals (CI).
Results: Among 407,663 adults with vertebral fractures, 29,158 (7.2%) sustained SCI. Patients with subaxial cervical fractures (C3–C7; aOR 2.87, 95% CI 2.78–2.95; p<0.001) and lower thoracic fractures (T9–T12; aOR 1.52, 95% CI 1.47–1.57; p<0.001) displayed strong odds for SCI. Male sex (female aOR 0.73, 95% CI 0.71–0.75; p<0.001) and assault as the injury mechanism (aOR 1.37, 95% CI 1.29–1.45; p<0.001) also emerged as key factors. Hospital course variables including discharge to critical care (aOR 4.19), and complications such as catheter-associated urinary tract infection (aOR 3.05) and acute respiratory distress syndrome (aOR 1.63) also demonstrated associations with SCI presence (all p<0.001).
Conclusion: In this national cohort, 7.2% of adults with vertebral fractures had SCI. Fracture level, sex, and injury mechanism contributed to SCI risk, while certain hospital complications and discharge patterns also correlated with SCI presence. These findings may help support stratification of vertebral fracture patients at elevated risk for SCI.
Fc-Engineered Monoclonal Antibodies Targeting neoGFAP™ as a Disease-Modifying Immunotherapy for Traumatic Brain Injury
Kevin Wang1,2, Zhihui Yang2, Devin Jackson3, Katie Tehas3, Anthony DeLizza3, Caroline Popper3, Todd Kilbaugh4, Franklin Okumu4, Henry Lowman4,
1Foundation for Applied Molecular Evolution, Alachua, USA, 2University of Florida, Gainesville, USA, 3Gryphon Bio, South San Francisco, USA, 4Owl Therapeutics, Cambridge, USA
Background: Traumatic brain injury (TBI) lacks FDA-approved disease-modifying therapies. Astrocytic injury generates and releases pathological protein debris that may propagate secondary neurodegeneration.
Objective: To test a novel proteoform-selective immunotherapy for TBI, we developed Fc-engineered monoclonal antibodies (mAbs) targeting neoGFAP™, a calpain-cleaved 38–40 kDa GFAP proteoform released from injured astrocytes.
Methods: We generated mAbs against the neoGFAP™ N-terminal neo-epitope or a conserved core epitope (shared with total GFAP) and assessed affinity, cross-species reactivity, and FcγR-dependent microglial phagocytosis. Fc variants with enhanced or reduced effector function were tested in mouse controlled cortical impact using target engagement (neoGFAP™/total GFAP), pharmacodynamic biomarkers (p-tau/tau, NfL, etc.), neuropathology, and behavior.
Results: A lead neo-epitope–selective mAb bound neoGFAP™ with apparent dissociation constant <10 pM and showed no detectable binding to total GFAP (human, cynomolgus, mouse). Active immunization or passive dosing reduced cortical neoGFAP™ or total GFAP, lowered p-tau/tau in blood, and improved spatial memory. Enhanced-effector asymmetric Fc formats achieved >80% target depletion in CSF by day 14 post-injury and produced significant sensorimotor and cognitive benefit versus isotype controls, outperforming reduced-effector formats and thereby confirming microglial clearance of opsonized target as the primary mechanism of action.
Conclusions: Targeting the injury-generated neoGFAP™ proteoform with Fc-optimized mAbs supports a biomarker-guided, disease-modifying immunotherapy strategy for neurotrauma and provides a mechanistic framework to couple astrocytic debris clearance with improved functional recovery.
Feasibility of Implementing a Stakeholder-Developed Precision Medicine Dashboard for Post-Acute Traumatic Brain Injury: TBI-BRIDGE
1UCSF, San Francisco, United States, 2UCSF Bakar Computational Health Sciences Institute, San Francisco, United States, 3Weill Institute for Neurosciences, San Francisco, United States, 4Medical College of Wisconsin, Milwaukee, United States, 5ZSFG Brain and Spinal Injury Center, San Francisco, United States
Objective: 1) To leverage a point-of-care precision medicine dashboard (BRIDGE) for visualization of concussion/traumatic brain injury (TBI) features, and 2) to determine deployment feasibility and use of TBI-BRIDGE within a single-center neurorecovery program and related post-acute TBI care clinic (PACC).
Background: A large volume of clinical information must be synthesized and exchanged between clinicians and post-TBI patients. The new Clinical, Biomarker, Imaging, and Modifier (CBI-M) framework would also benefit from clearer visual tools to improve clinical discussions. BRIDGE is an electronic health record (EHR)-integrated, adaptable, scalable digital health tool undergoing local development for TBI (TBI-BRIDGE).
Design/Methods: Reciprocal development and iteration phases included 1) study team knowledge sharing, 2) mock-up development, 3) qualitative evaluations of mock-ups by clinicians and patients, and 4) TBI-BRIDGE development. Phase (5) is focused on TBI-BRIDGE implementation with subsequent qualitative and quantitative feedback.
Results: Phases 1-3 comprised feedback from 19 patients (TBI) and 11 interprofessional clinical team members (CTM) with diverse specialty representation (neurology, neurosurgery, neuropsychology, occupational therapy, physical therapy, speech-language pathology, patient navigation). Patients were substantially more likely to report favorable responses (83.3%) to TBI-BRIDGE compared to usual care (33.3%) (Pearson Chi-square = 9.5, P <0.01). Both groups recommended longitudinal data visualizations (e.g., for patient reported outcome measures) to gauge recovery. CTM additionally recommended CBI-M visualization. Phase 4 comprised collaborative development of a deployable TBI-BRIDGE.
Conclusions: TBI-BRIDGE can enhance clinical encounters with meaningful patient-curated and injury-relevant data visualizations. Ongoing steps include determining deployment feasibility and use of TBI-BRIDGE within a single-center neurorecovery program and related PACC.
Female Mice Exhibit Amplified Cortical Metabolic Responses Following Mild Traumatic Brain Injury
1University Of Pennsylvania, Philadelphia, United States
Mild traumatic brain injury (mTBI) is a leading cause of long-term neurological dysfunction, causing a cascade of acute metabolic disruptions that drive secondary injury. The extent to which these responses differ by biological sex and brain region in the acute post-injury window remains elusive. We examined metabolic changes following mild controlled cortical impact (mCCI) in a mouse model using untargeted HILIC-MS, characterizing the ipsilateral cortex and hippocampus at 6 and 24 hours post-injury in female and male mice.
PLS-DA separated mCCI from sham across all sex-region-timepoint combinations, indicating widespread metabolic changes following mCCI. The cortex was disproportionately affected relative to the hippocampus, particularly at 24h post-injury. Female animals demonstrated broader metabolic responses, with 23 significantly altered metabolites in the female cortex at 24h compared to no significant changes in the male cortex at 24h. N-acetyl-L-aspartic acid (NAA) (VIP = 4.80), lactic acid (VIP = 4.40), and creatine (VIP = 2.85) were the top discriminating metabolites globally. Pathway analysis identified glutathione metabolism as an enriched injury-responsive pathway in multiple groups: female cortex 24h (enrichment ratio = 5.19, p = 0.0001), female hippocampus 24h (enrichment ratio = 2.52, p = 0.03), male hippocampus 24h (enrichment ratio = 3.15, p = 0.008).
These findings demonstrate that mCCI induces region-, timepoint-, and sex-dependent metabolic reprogramming, with female animals exhibiting an amplified cortical response at 24h post-injury. Together, these data implicate energetic failure, oxidative stress, and sex-specific metabolic dysregulation as early signatures of mTBI, providing a foundation for development of sex-stratified biomarkers and therapeutic targets.
From Acute Injury to PTSD: A Translational Study on Early Biological and Cognitive Predictors in Trauma Patients
Dr. Harumi Harakawa1, Preeti Kota2, Jane Chen2, Dr. Esther Sabban2, Dr. Rhea Dornbush1,2,
1Westchester Medical Center, Valhalla, United States, 2New York Medical College, Valhalla, United States
Post-traumatic stress disorder (PTSD) affects 10–30% of trauma survivors and is linked to psychiatric comorbidity, chronic illness, and elevated suicide risk.
This is an interim analysis of an ongoing prospective cohort study testing whether trauma screening, gut microbiome dysbiosis, systemic inflammation, intestinal and BBB permeability and cognitive function markers predict PTSD after physical trauma. Adults admitted 48 hours after trauma activation complete baseline assessments, including National Stressful Events Survey Short Scale (NSESSS), Montreal Cognitive Assessment (MoCA), Test of Premorbid Functioning (TOPF), and biological sampling of serum, saliva and a fecal swab. Assays will quantify inflammatory, stress-reactivity, microbiome, and short-chain fatty acid profiling. At two months, participants complete the Posttraumatic Stress Disorder Symptom Scale Interview for DSM-5 (PSSI-5) and repeat MoCA.
As of March 2026, 40 patients have been recruited and 20 completed follow-up. A moderate positive correlation was observed between NSESSS and PSSI-5 (r=0.667, p<0.01). There was a high correlation between NSESSS and symptoms related to re-experiencing (r=0.647, p<0.01) and arousal/reactivity (r=0.671, p<0.01). There was a moderate correlation between the baseline and follow-up MoCA (r=0.51, p<0.01). Patients lost to follow-up (n=12) had significantly lower mean MoCA scores than those retained (19.7 versus 24.0, p<0.01).
Current results reinforce the validity of the NSESSS to predict development of PTSD after physical trauma, particularly re-experiencing and arousal symptoms. Participants with lower cognitive function are at risk for loss to follow-up PTSD assessment and treatment. Biological assays will be conducted to further elucidate predictive biomarkers of PTSD to enhance early detection and treatment.
Functional, Sensorimotor, and Cognitive Outcomes Following Unilateral MCAO in Rats
1Psychogenics, Inc, Paramus, United States
Ischemic stroke remains a leading cause of disability, highlighting the need for robust preclinical models. The objective of this study was to validate a middle cerebral artery occlusion (MCAO) model in rats by characterizing infarct formation, neurological deficits, and functional impairments relevant to human stroke. Adult male Sprague Dawley rats (10 weeks of age, 280-320g) underwent 2-hour intraluminal filament occlusion of the left middle cerebral artery followed by reperfusion. Location and extent of infarct were assessed 24h post-reperfusion using triphenyltetrazolium chloride staining. Functional outcomes were evaluated using a comprehensive behavioral battery, including neurological scoring, beam balance, horizontal ladder, corner, cylinder, gait analysis, and Morris water maze (MWM) testing.
MCAO produced reproducible infarcts predominantly in the cortex and striatum. MCAO animals exhibited significant increases in neurological scores, with peak deficits at the end of occlusion and persistent impairments up to 2-weeks post-stroke. Gross motor deficits and balance impairments were observed in the beam balance test, while fine motor dysfunction in the contralateral forelimb was detected using the horizontal ladder task. Robust sensorimotor asymmetry was demonstrated by both the corner and cylinder tests, persisting through 4-weeks post-MCAO. In the MWM assessment, performed at 5-weeks post-stroke, MCAO rats showed increased latency and distance to reach the hidden platform during training, indicating delayed spatial learning, although probe trial performance (an indicator of spatial memory) was comparable to sham animals.
In conclusion, this validated MCAO model reliably reproduces key pathological and functional features of human ischemic stroke and provides a sensitive platform for therapeutic evaluation.
Geriatric TBI Admission Institutional Practice Patterns: A TRACK-TBI Survey Study
1Department of Neurology, University of Wisconsin – Madison, 2Department of Neurology, University of Wisconsin – Madison, 3Department of Neurology and Rehabilitation Medicine, University of Cincinnati, 4Department of Emergency Medicine, University of Wisconsin – Madison, 5Department of Neurological Surgery, University of California, San Francisco, 6Department of Neurosurgery, University of Washington, 7Department of Neurological Surgery, University of Pittsburgh, 8Department of Neurology, University of Pennsylvania, 9Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania
Introduction: Geriatric patients with acute TBI have higher rates of clinical decline during hospitalization, but intensive care unit (ICU) admission has been associated with worsened post-hospitalization cognitive status in non-TBI geriatric populations. ICU admission criteria for geriatric TBI are not well defined.
Objective: Characterize admission criteria in geriatric acute TBI hospitalizations.
Methods: A survey was sent to the 18 clinical sites in the TRACK-TBI U01 study. Surveys were returned by 27 providers from 16 sites (88% site response) between June 2020-2021 and again in April 2024 for additional sites. 10 responses were from intensivists and 17 responses from neurosurgeons.
Results: In 68% of responses, age ≥ 65 was considered a possible or always indication for ICU admission after acute TBI. In 92% of responses, TBI patients aged ≥ 80 would be admitted to the ICU if they needed life-saving treatment or had undergone intubation in the ER. 8% of ICU admissions for patients aged ≥ 80 required prior co-morbidity assessment. Most respondents (64%) noted that one of the top reasons for not admitting patients aged ≥ 75 to the ICU was if the patient or family did not want escalation of care. 16% would not admit to the ICU based on prognosis as a factor.
Conclusion: There was general agreement among institutions that geriatric populations with severe brain injury were usually admitted to the ICU for life saving measures, but there was significant variability regarding age as an indication for ICU admission after an acute TBI.
GFAP, NfL, Tau and Inflammatory Cytokines Predict Glascow Outcome Score Extended at Discharge in Moderate to Severe TBI Patients
1Johns Hopkins University, Baltimore, United States, 2Johns Hopkins University School of Nursing, Baltimore, United States, 3Johns Hopkins University School of Medicine, Baltimore, United States, 4University of Chicago, Chicago, United States, 5Uniformed Services University of the Health Sciences, Bethesda, United States
Introduction: This study aimed to identify how a combination of acute blood levels of brain related injury markers (BRIMs) and cytokines performs in the clinical assessment of functional recovery outcomes at discharge from hospitalized care in patients with moderate-severe traumatic brain injury (msTBI). Predicting poor recovery outcomes during acute injury may allow providers to make rehabilitation plans earlier, minimizing critical time during the most malleable period of recovery following TBI.
Methods: Concentrations of BRIMs (GFAP, NfL, tau, and UCH-L1) and cytokines from plasma samples collected within 6 h of injury were measured. Functional recovery at discharge was measured using the Glasgow Outcome Scale-Extended (GOSE). GOSE scores were dichotomized: favorable (GOSE > 4) and unfavorable (GOSE ≤ 4) recovery outcomes. Generalized linear models (GLMs) were created using significant BRIMs and cytokines as predictors. Receiver operating characteristic area under the curve (AUC) analyses were computed to determine predictive value of the models.
Findings: GLMs including BRIMs and cytokines as predictors performed marginally better than BRIMs alone (GFAP, NfL, tau, UCH-L1, age, sex; AUC [95% CI]: 0.816 [0.746-0.887]). Model 1 included GFAP, Tau, NfL, CCL8, CXCL8, age, sex (AUC [95% CI]: (0.834 [0.765-0.903]); Model 2 included GFAP, Tau, NfL, IL-1β, CXCL8, age, sex (AUC [95% CI]: 0.830 [0.762-0.899]). Model 2 achieved higher specificity compared to BRIMs alone (0.800 vs. 0.692).
Implications: Our findings indicate cytokines and BRIMs predict functional recovery outcomes at discharge in msTBI patients better than BRIMs alone. This finding may improve clinical planning for hospitalized msTBI patients.
Glutathione Treatment and the Looming and Visual Cliff Tests as Functional Assessments of Visual Performance in Mice Following Closed Head Impact Model of Engineered Rotational Acceleration (CHIMERA) Brain Injury
1Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, United States, 2Department of Anatomy, Physiology & Genetics, Uniformed Services University, Bethesda, United States, 3Preclinical Behavior and Modeling Core, Department of Laboratory Animal Resources, Uniformed Services University of the Health Sciences, Bethesda, United States, 4Center for Drug Design, College of Pharmacy, University of Minnesota, Minneapolis, United States
Mild traumatic brain injury (mTBI) can present with a wide range of symptoms, including visual deficits. Oxidative stress is known to contribute to the onset and progression of TBI symptomatology. Endogenous glutathione (GSH) is an antioxidant that is depleted in injured and aging models. Ψ-GSH, a chemically modified GSH, more efficiently crosses the blood-brain barrier and is resistant to the breakdown of Ɣ-glutamyl transpeptidase. We implemented a long-term study to explore how mTBIs contribute to visual deficits, and how Ψ-GSH could be used as a treatment. CHIMERA is a clinically relevant model that causes mTBI through forces of acceleration and deceleration. We performed four injuries (once a day for four days), with mice receiving Ψ-GSH injections three times a week for seven weeks, beginning two weeks before CHIMERA. Six months after injuries, we performed visual cliff (three trials/animal) and looming test (five trials/animal). Visual cliff data demonstrated that Ψ-GSH animals moved to the “safe side” of the box significantly sooner than vehicle treated animals (p=0.017), while looming results demonstrated that animals who had received 4x CHIMERA took significantly more time to enter the shelter after the looming stimulus than animals who received no injury (p<0.001). Mice displayed shorter latencies to shelter on trial two compared to trial one (p<0.001), however CHIMERA mice who received vehicle injections were significantly more likely to not enter the shelter at all on trial 2. Overall, CHIMERA injury led to decreased visual performance, and Ψ-GSH had long-term benefits.
Headache Burden in Former Professional Football Players: Associations with Neurotrauma Exposure and Psychological Outcomes: An NFL-LONG Study
1Medical College Of Wisconsin, Milwaukee, USA, 21. Departments of Emergency Medicine and Pediatrics, Harvard Medical School,2. Division of Emergency Medicine, Boston Children’s Hospital, Boston, USA, 3Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, USA, 4Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, USA, 51. University of Missouri-Kansas City,2. Psychological and Neurobehavioral Assocs., Inc, 1. Kansas City,2. Port Matilda, USA, 6Department of Kinesiology, Michigan State University, East Lansing, USA, 71. The Micheli Center for Sports Injury Prevention, Boston Children's Hospital,2. Departments of Emergency Medicine and Pediatrics, Harvard Medical School,3. Division of Emergency Medicine, Boston Children's Hospital, 1. Waltham,2. Boston,3. Boston, USA, 8Department of Neurosurgery and Neurology, Medical College of Wisconsin, Milwaukee, USA, 9Department of Neurosurgery and Neurology, Medical College of Wisconsin, Milwaukee, USA
Background: Chronic headaches and their potential impact on psychological well-being remain understudied in former contact sport athletes. This study examined associations between repetitive neurotrauma (concussion history and head impact exposure), headache burden, and mental health in former professional football players.
Methods: Former professional football players (N=178; Mage=59.96±6.23) completed validated measures including the Headache Impact Test-6 (HIT-6), Beck Depression Inventory-II (BDI-II), and Beck Anxiety Inventory (BAI). Neurotrauma history included concussion history and the three primary metrics from the Cumulative Head Impact Index (CHII; total, linear acceleration, and rotational acceleration). Logistic regression models were fit to evaluate associations between neurotrauma history and headache burden, and Spearman correlations were used to evaluate the association between headache burden and mental health outcomes, as measured by the BDI-II and BAI.
Results: Former players reported a range of headache severities: Little to no (68.5%), some (12.9%), substantial (6.2%), and severe (12.4%). Although 18.6% reported substantial or severe headache burden, neither concussion history nor CHII were significantly associated with total HIT-6 scores (ps > .05). Conversely, higher HIT-6 scores were significantly associated with higher BDI-II (r=.45, p<.001) and BAI scores (r=.45, p<.001).
Conclusion: Concussion history and CHII are not associated with headache burden among former professional football players. Nearly a third of the sample (31.5%), however, endorsed some headache burden, which was strongly associated with mental health symptoms. Effective management of headache symptom burden has the potential to improve mental health function among former professional football players.
Headache Burden Independently Predicts Impairment in Cognitive Performance in Persisting Post-Concussion Symptoms
1Department of Neurology, UCLA, Los Angeles, United States, 2Department of Pediatrics, UCLA, Los Angeles, United States, 3Department of Psychiatry, UCLA, Los Angeles, United States, 4BrainSPORT, Department of Neurosurgery, UCLA, Los Angeles, United States
Objective: To determine if self-reported headache burden independently interferes with performance-based cognitive assessment in adults with persisting post-concussive symptoms (PPCS).
BACKGROUND: Post-traumatic headaches and cognitive difficulties frequently co-occur in PPCS. However, it remains unclear whether individual variability in performance-based cognitive assessment is directly attributable to headache burden independent of overlapping factors, including sociodemographics, mood, anxiety, fear avoidance, and resilience.
Methods: Forty-six adults with high PPCS burden participated in a 3-month clinical trial evaluating neuromodulation. Fluid and crystallized cognition (NIH Toolbox Cognition Battery), headache burden, and psychosocial factors were assessed longitudinally. Hierarchical and LASSO regressions evaluated whether headache burden explained variance in fluid cognition independent of covariates at baseline and as a change over time.
Results: Lower headache burden (Headache Impact Test) consistently predicted better fluid cognition at baseline and longitudinally. At baseline, lower headache burden and greater emotional resilience (Connor-Davidson Resilience Scale) independently predicted superior fluid cognition (19% of variance explained, p=0.005). Over three months, reductions in headache burden emerged as the strongest longitudinal predictor of cognitive improvement (17% of variance, p=0.003). LASSO modeling corroborated these findings, demonstrating that all effects were entirely independent of age, sex, education, current medication, prior history of migraine and learning disability, time since injury, and crystallized cognition.
Conclusion: Headache burden is a consistent and independent predictor of poorer performance on fluid cognitive measures. Conversely, reductions in headache severity are associated with improvements in fluid cognition in PPCS, highlighting headache management as a critical target for interventions aimed at supporting cognitive recovery.
Higher Prevalence of Cardiovascular Dementia Risk Factors in Women with a History of Intimate Partner Violence
1Brain Injury Research Center, Icahn School Of Medicine At Mount Sinai, New York, United States, 2School of Health and Wellbeing, University of Glasgow, Glasgow, United Kingdom, 3Scottish Brain Health Sciences, Edinburgh, United Kingdom, 4University of St. Andrews, St. Andrews, United Kingdom, 5Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, United States, 6Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, United States, 7Heritage College of Osteopathic Medicine, Ohio University, Ohio, United States
Background: Intimate partner violence (IPV), particularly physical IPV, is an underrecognized cause of traumatic brain injury (TBI) and repetitive head impacts (RHI). TBI is a modifiable risk factor for Alzheimer's disease and related dementias (ADRDs) and evidence suggests it elevates cardiovascular disease, another ADRD risk factor. However, the relationship between IPV-related TBI and dementia risk profiles has not been thoroughly examined. We hypothesized that IPV exposure would be associated with elevated prevalence of modifiable ADRD risk factors, particularly cardiovascular risk factors, in women in mid-to-late life.
Methods: We conducted a cross-sectional analysis of female UK Biobank participants with complete lifetime IPV data(n=84,890). IPV was categorized by increasing likelihood of TBI/RHI: no exposure, emotional IPV, physical IPV low/medium-frequency, and physical IPV high-frequency. Twelve modifiable ADRD risk factors were derived from self-report questionnaires, medical assessments, and linked health records. Adjusted prevalence ratios (aPRs) were estimated using robust modified Poisson regression, controlling for age, ethnicity, and socioeconomic status.
Results: High-frequency physical IPV was associated with substantially elevated prevalence of cardiovascular risk factors, including smoking (aPR=2.56, 95%CI:2.32-2.83), diabetes (83% higher; aPR=1.83, 95%CI:1.57-2.13), high cholesterol (64% higher; aPR=1.64, 95%CI:1.46-1.84), obesity (53% higher; aPR=1.53, 95%CI:1.44-1.64), and hypertension (42% higher; aPR=1.42, 95%CI:1.33-1.53). Depression and social isolation were also elevated across IPV exposure groups.
Conclusions: IPV-related TBI may contribute to elevated dementia risk via cardiovascular profiles distinct from the broader psychological and social consequences of IPV. IPV survivors represent an underserved, high-risk population for whom trauma-informed brain health education, and targeted cardiovascular risk prevention strategies are urgently needed.
Hippocampal Network Dysfunction and Altered Sharp-Wave Ripples after Closed Head Injury
1Department of Neurosurgery, The University of Oklahoma Health Campus, Oklahoma City, United States
Traumatic brain injury (TBI) is a leading cause of long-term cognitive impairment, resulting in memory deficits, attention, and executive function. Among affected brain regions, hippocampus is particularly vulnerable due to its critical role in learning, spatial navigation, and memory consolidation. However, the circuit-level mechanisms underlying these impairments remain poorly understood. We used closed head injury (CHI) to characterize hippocampal dysfunction at behavioral, circuit and synaptic levels at 14 and 30 days-post-injury (dpi). Hippocampal dependent memory was assessed using novel object location task. Neuronal network activity across CA1 layers of the hippocampus was measured using implanted high-density silicon probes in freely moving animals during home cage resting and open field exploration across different environments. We further examined synaptic transmission in CA3-CA1 pathway using multi electrode array in acute hippocampal brain slices. We found that CHI mice exhibited impaired spatial discrimination at 14 dpi without changes in exploratory activity. Analysis of local field potentials during non-REM sleep in home cage recordings showed significant alterations in sharp wave ripples (SWR) features - high frequency oscillations essential for memory consolidation. Specifically, CHI mice exhibited increased SWRs power at 14 dpi, whereas SWR power was significantly reduced at 30 dpi, suggesting time-dependent changes in hippocampal network activity after injury. We further examined experience-dependent modulation of SWRs by comparing resting periods before and after novel environment exposure. Sham mice showed a significant increase in SWR rate following novel environment exposure. Together, these studies highlight hippocampal network alterations that may contribute to cognitive dysfunction after TBI.
Home-Cage Monitoring as a Sensitive Tool for Detecting Subtle Behavioral Alterations Following Minimal Traumatic Brain Injury
Chaim G. Pick1,2, Lior Bikovski3,4
1Department of Anatomy and Anthropology, Gray Faculty of Medical and Health Sciences, Tel-Aviv University, Tel-Aviv 6997801, Israel 2Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel 3Department of Human Molecular Genetics & Biochemistry, Gray Faculty of Medical and Health Sciences, Tel-Aviv University, Tel-Aviv 6997801, Israel 4Myers Neuro-Behavioral Core Facility, Gray Faculty of Medical and Health Sciences, Tel-Aviv University, Tel-Aviv 6997801, Israel
Mild traumatic brain injury (mTBI) produces heterogeneous behavioral outcomes influenced by genetic background and experimental context. This study examined how genetic background shapes the magnitude (severity) and variance of mTBI-related behavioral responses using two mouse strains: C57 and outbred ICR mice. Animals underwent a closed-head weight-drop mTBI model and were assessed across a behavioral battery spanning sensorimotor, affective-like, cognitive, and spontaneous home-cage behavior domains. Conventional short-duration assays showed limited injury effects, with most differences driven by strain. Gait analysis revealed strain differences in hind paw base of support and running speed under control conditions that were absent after mTBI. Running speed also differed between ICR controls and mTBI mice. Continuous home-cage monitoring revealed circadian phase-specific injury effects only in ICR mice: mTBI animals traveled less during the active phase, showed smaller active-to-inactive differences in distance traveled, shelter visits, and shelter duration, and displayed increased shelter occupancy during the active phase on day 2. No comparable injury effects were observed in C57 mice. Habituation patterns also differed by strain: in C57 mice, it was observed mainly in control activity during the active phase, whereas ICR mice showed habituation in both groups for activity and distance, primarily during the active phase. Our findings suggest that mTBI-related behavioral changes may vary across measures and strains, and that circadian-phase-sensitive, low-stress monitoring can help detect subtle effects that are not captured by conventional short-duration assays. These observations highlight the value of considering strain selection and behavioral context, given the heterogeneous nature of mTBI-related behavioral outcomes.
How Many Hit Matters? Defining the Threshold for Tau Mediated Degeneration after Repetitive Traumatic Axonal Injuries In-Vitro
1Department of Neurosurgery, CBIR, University of Pennsylvania, Philadelphia, United States
While Traumatic Axonal Injury (TAI) is a recognized risk factor for CTE, the precise biomechanical thresholds and long-term molecular kinetics that drive the transition from repetitive axonal strains to progressive tauopathy remain poorly understood. Utilizing a well-characterized micro-patterned axonal track in vitro model, we subjected primary rat cortical neurons to repetitive dynamic stretch injuries at varying strain rates and frequencies. We found that repetitive TAI induced a dose-dependent influx of extracellular Ca2+, triggering calcium-mediated cytoskeletal degradation. Notably, even at sub-threshold injuries, repetitive injuries, unlike single insult, triggered acute axonal undulation, varicose swelling, and accumulation of microtubule breakdown products including phosphorylated tau (p-tau). Over the course of hours to days, we observed increased p-tau accumulation in somatodendritic compartments, while simultaneously observing a corresponding depletion of p-tau within the distal axons. Interestingly, the somatodendritic accumulation of p-tau, coincided with the breakdown of Axon initial segment (AIS), suggesting that the AIS retrograde transport barrier is mechanically compromised by repetitive TAI, facilitating the leakage of p-tau into the soma – a critical step in the pathogenesis of CTE. Together, our findings demonstrate that repetitive sub-threshold loading, even at strains that do not cause immediate axonal rupture, has a potential to establish intracellular pre-conditions for tau fibrillation and CTE.
Human iPSC-Derived Tissue Engineered Spinal Tracts Promote Axonal Extension and Integration Following Spinal Cord Injury
Dr. Justin Burrell1
1University of Pennsylvania, Philadelphia, United States
Spinal cord injury (SCI) disrupts long-distance axonal pathways required for neural circuit function. Engineered neural tissues offer a potential strategy to reconstruct lost circuits by providing organized neuronal populations capable of extending axons across macroscopic distances and interfacing with host circuitry. We evaluated novel tissue engineered spinal tracts (TE-STs) generated from human induced pluripotent stem cell (iPSC)-derived spinal neuronal populations, including motor neuron, sensory neuron, and interneuron phenotypes. TE-STs were assembled within hydrogel microcolumns within an extracellular matrix lumen designed to support directional axonal growth >1cm to span mature SCI lesions. Neuronal phenotype and long-distance axonal extension were characterized in vitro using neuronal lineage and axonal markers. Pre-grown TE-STs were then transplanted into athymic rats following thoracic balloon compression SCI. Histological analyses revealed TE-ST neuronal survival and axonal extension into host tissue. In animals receiving TE-STs, dense longitudinal axonal tracts were found within the microcolumn lumen spanning the lesion, suggesting a mix of graft and host axons. In contrast, control animals receiving acellular microcolumns showed modest ingrowth of host axons, absent continuous axonal tracts. Animals receiving TE-STs showed modest functional improvement compared to animals receiving acellular microcolumns as early as 6 weeks post-injury. These findings support the feasibility of assembling human stem cell-derived neurons into engineered axonal pathways capable of surviving transplantation and interacting with injured spinal tissue. Ongoing analyses are evaluating how neuronal subtype composition influences axonal organization, host integration, and functional recovery. Overall, TE-STs represent a promising platform for reconstructing disrupted neural circuits following SCI.
Human Multicellular In Vitro Brain Models Reveal How Injury Severity Drives Distinct Neurodegenerative Trajectories
1University Of Cincinnati, Cincinnati, United States
Traumatic brain injury (TBI) is a major risk factor for multiple neurodegenerative disorders, including
Alzheimer’s disease (AD) and chronic traumatic encephalopathy (CTE). However, the mechanisms that determine why different types and severities of injury lead to distinct disease trajectories remain poorly understood. Progress in the field has been limited by the lack of human experimental systems capable of modeling-controlled injury and long-term pathological evolution. Here, we demonstrate that multicellular human in vitro brain models enable mechanistic interrogation of how injury biomechanics shape neurodegenerative outcomes. Using engineered 3D human brain cultures composed of neurons, astrocytes, microglia, and neurovascular elements, we applied controlled mechanical trauma of varying severity that reproduces clinically relevant injury conditions and compared transcriptomic signatures from the model with datasets derived from human patients experiencing either moderate traumatic injury or repetitive mild head impacts.
Moderate injury produced sustained mitochondrial dysfunction, metabolic instability, and accumulation of Alzheimer ’s-associated markers, including phosphorylated Tau, APP, and altered Aβ42/40 ratios, linking cellular bioenergetic failure to AD-like neurodegenerative progression. In contrast, repetitive mild injury induced a staged pathological trajectory characterized by early synaptic disruption, delayed tau phosphorylation, axonal degeneration, and chronic neuroinflammatory signaling consistent with early CTE-like pathology. Importantly, transcriptomic and molecular signatures observed in these models converge with patterns identified in human TBI and CTE datasets, supporting the physiological relevance of the system.
Thus, systematic manipulation of injury magnitude, frequency, and interval revealed that injury biomechanics determine whether neural tissues recover, develop delayed pathology, or transition toward progressive neurodegeneration.
Hunting for a Molecular Phenotype of Rod Microglia in TBI and Neurodegeneration
1Department of Physical Medicine and Rehabilitation, Michigan Medicine, Ann Arbor, USA, 2Concussion Center, University of Michigan, Ann Arbor, USA, 3Neuroscience Graduate Program, Michigan Medicine, University of Michigan, Ann Arbor, USA, 4ASU-Banner Neurodegenerative Disease Research Center, Arizona State University, Tempe, USA, 5School of Biological and Health Systems Engineering, Arizona State University, Tempe, USA
Microglia, the brain’s resident immune cells, become activated after inflammatory events such as traumatic brain injury (TBI) and Alzheimer’s disease (AD). One elusive activated morphology, rod microglia, is defined microscopically by an elongated soma, with processes extending into linear trains across the cortex. Although rod microglia are documented in clinical and experimental neurological conditions (e.g. TBI, AD), their molecular identity and function remain elusive. We hypothesize that rod microglia exhibit a defining set of upregulated genes compared to other non-rod microglial morphologies. Rod microglia and non-rod microglia in post-mortem AD cortical tissue were visualized with immunohistology and isolated using laser-capture microdissection. Single-cell RNA sequencing followed by differential expression analysis (DESeq2) identified genes upregulated in rod microglia compared to non-rod microglia (rod-enriched genes). Upregulated genes were associated with immune activation, stress-induced transcriptional and epigenetic changes, and structural remodeling. Pathway analysis (log2FC>0, p<0.05) indicated rod microglia roles associated with inflammation and metabolism. To validate candidate rod-enriched genes (Cfi, Abcg2, Crispld2, Alox5ap), we induced midline fluid percussion injury in rats and probed brain tissue by fluorescent in situ hybridization (RNAscope). Cfi, Abcg2, and Crispld2 showed non-specific expression in non-rod microglia, whereas Alox5ap, a leukotriene key regulator of the microglial inflammatory cascade, was expressed in both rod and non-rod microglia. Thus, rod microglia remain a unique activated microglial state that undergoes structural and metabolic reorganization. The current workflow builds a molecular profile of rod microglia, establishing fundamental targets that inform cellular function and guides future therapeutic strategies.
Hydrogen Inhalation Attenuates Oxidative Stress After Experimental Traumatic Brain Injury
1Boston Children's Hospital, Boston, United States, 2Harvard Medical School, Boston, United States, 3Micheli Center for Sports Injury Prevention, Waltham, United States
Traumatic brain injury (TBI) induces oxidative stress that contributes to cellular energy crisis, increased susceptibility to secondary injury, and worsened neurological outcomes. Molecular hydrogen has been proposed as a therapeutic antioxidant, yet its effects on oxidative stress following TBI remain incompletely characterized. In this study, adult male C57BL/6 mice (9–10 weeks old) were subjected to experimental mild TBI using a drop-weight model and exposed to hydrogen inhalation (2% hydrogen, 21% oxygen), either for 5 hours or continuously for 3 days following injury. Redox status was evaluated by measuring the ratio of reduced to oxidized glutathione (GSH/GSSG) in hippocampal tissue. TBI significantly reduced the GSH/GSSG ratio compared with sham controls (p = 0.0001), indicating disruption of redox balance after injury. At an early post-injury time point (5 h), hydrogen exposure significantly restored the GSH/GSSG ratio following TBI (p = 0.0049), bringing levels close to those observed in sham controls. At three days post-injury, hydrogen exposure showed a trend toward improvement in the GSH/GSSG ratio, although the difference was not statistically significant (p = 0.1857). Circulating biomarkers of brain injury, including GFAP, neurofilament light chain (NF-L), ubiquitin carboxy-terminal hydrolase-1 (UCH-L1), and tau, were measured at three days post-injury and showed comparable levels between groups. Together, these results suggest that hydrogen inhalation attenuates oxidative stress following TBI without altering circulating biomarkers of neuronal injury. It may represent a promising strategy to modulate oxidative stress after brain injury.
Identifying Motor Responders to Epidural Spinal Cord Stimulation for Spinal Cord Injury
1University Of Minnesota, Department of Biomedical Engineering, Minneapolis, United States, 2University of Minnesota, Department of Neurosurgery, Minneapolis, United States
Spinal cord injury (SCI) presents differently in each patient. Epidural spinal cord stimulation (eSCS) has been shown to improve its most visible symptoms: paralysis and muscle spasms below the level of injury. To assess eSCS for SCI, researchers need a metric that takes into consideration the heterogeneous presentation of SCI and improvements in motor function that have been demonstrated using eSCS.
This work defines quantitative change thresholds for characterizing responders to relevant motor outcomes and applies them to identify responders to eSCS for motor improvement after SCI.
Data was collected at pre-implantation baseline and 12 monthly follow-up visits from 20 ESTAND clinical trial participants with chronic motor complete thoracic SCI. Three motor domains were assessed: electromyogram power during the Brain Motor Control Assessment (BMCA), assisted and unassisted cycling power, and Modified Ashworth Scores (MAS). A linear mixed effects model was developed to assess improvements in each motor domain with stimulation (stim on/off data collected each visit) or over time in our trial (single assessment per visit).
95% of participants significantly improved in at least one motor outcome, 45% in at least 2, and 20% in all 3 (for all, p<0.05). 60% showed significant improvement in BMCA, 55% in cycling power, and 58% in MAS.
No individual outcome measure suggests improvement in motor function at a population level. However, when the heterogeneity of SCI motor impairment presentation and recovery profiles is built into assessment using our metric, 95% of our SCI participants showed some improvement in motor function.
Identifying the Threshold from Mild to Moderate Traumatic Brain Injuries in Rats Using a Staircase Procedure
1Indiana University, Bloomington, United States
The rat weight drop (WD) model of mild traumatic brain injury (mTBI), introduced by Marmarou and colleagues, originally involved dropping a weight onto a helmeted skull, using different masses and heights. However, researchers have not consistently scaled the WD to the animal’s mass, and, surprisingly, animal weights are routinely not reported, which may limit replicability. Here, we sought to identify the WD-mass threshold that defines the transition between mild and moderate TBI. Moderate TBI was defined as a gross brain defect observed at euthanasia 1 hour after injury, which may be similar to radiological findings in humans. We used a psychophysical staircase procedure to determine the threshold from mild to moderate TBI by adjusting the mass of the WD in multiples of animal body mass. Of the 20, three-month old, male Long Evans rats, 7 animals were identified by two non-blinded experimenters to have a moderate TBI with nonexclusive hematological features: 7 subdural, 2 epidural, and 1 transtentorial hematomas. We did not observe apnea or skull fractures. We estimate that the 80%-to-20% mild-to-moderate threshold is 3.83 multiples of body mass; for an average rat in our experiment (393g), the threshold weight is 1505g. In our previous studies with a fixed 450g weight, on average, male and female rats weighed 343g and 217g, respectively, which corresponds to 1.31 and 2.07 multiples of body weight, respectively. Our current findings are expected to identify a mass to produce mTBIs with replicable behavioral results.
IL-1β/IL1Recptor-1 Signaling Mediates Synaptic Dysfunction and Cognitive Deficits After
1Massachusetts General Hospital, Boston, United States, 2Boston Children's Hospital, Boston, United States
Objective: Our prior work demonstrated that inflammasome activation is a key mechanism underlying neurologic dysfunction following repetitive mild TBI. We hypothesize that neuronal IL-1β signaling is induced by NMDA receptor activation and drives synaptic biochemical changes associated with cognitive deficits in an adolescent mouse model of repetitive mild closed head injury (rmCHI).
Methods: Adolescent (postnatal day 38) mice were subjected to four daily weight drop (54g, 52”) CHI (4HD). Post-injury cognitive function was tested with a Morris water maze (MWM). Proteomics and Western blot analyses of synaptosomes examined the effect of 4HD on synaptic biochemistry in wild-type (WT) and global IL-1 receptor-1-deficient mice (IL1R-1r/r). IL-1R-1 was restored in neurons (CamkII-CreERT2/IL1-R-1r/r) or brain endothelial cells (Slco1c1-CreERT2/IL1-R-1r/r) by tamoxifen administration. Data were analyzed using t-tests/ANOVA.
Results: WT mice with cognitive deficits after 4HD (MWM+) (p<0.0001) but not sham or MWM- (no persistent cognitive deficits) had demonstrated IL-1β activation and reduced phosphorylation of synapsin-1 (Ser605 and Ser9) and GluA1 (Ser831) in hippocampal synaptosomes (p<0.05), all of which were abrogated in IL-1R-1r/r mice or by treatment of WT mice with the NMDA receptor antagonist memantine. Deletion of IL-1R-1 also protected against post-injury cognitive deficits. Following tamoxifen-induced recombination 2-3 weeks after 4HD, MWM learning deficits developed in CamkII-CreERT2/IL-1R-1r/r mice (p<0.05) but not in Slco1c1-CreERT2/IL-1R-1r/r mice.
Conclusion: IL-1R1 signaling downstream of NMDA receptor activation contributes to synaptic pathology and cognitive impairment following rmCHI. Inhibition of neuronal IL-1β/IL-1R-1 signaling may provide a therapeutic strategy to preserve synaptic and cognitive function after injury.
IL-1β-Containing Microglial Extracellular Vesicles Mediate Brain-Heart Communication After Traumatic Brain Injury in Mice
Brianne E. Dillon1, Binh Minh N. Nguyen1, Aubrienne Krysiewicz-Bell1, Dr. Hongmei Yang1, Dalila Marzialo1, Ionita Ghiran2, Dr. Michael Whalen1,
1Massachusetts General Hospital, Boston, United States, 2Beth Israel Deaconess Medical Center, Boston, United States
Objective: Epidemiological studies show an increased risk of cardiovascular disease after traumatic brain injury (TBI) through unknown mechanisms. We hypothesized that microglial extracellular vesicles (mEVs) promote cardiac inflammation via IL-1β signaling in a mouse controlled cortical impact (CCI) model.
Methods: Cardiac inflammasome activation after CCI was assessed in ASC reporter mice and IL-1β in isolated cardiac cells by western blot. Brain cell–specific EV trafficking to the heart was examined using inducible hCD63-GFP EV reporter mice with GFP-labelled EVs from neurons, astrocytes, brain endothelium, and microglia. Circulating brain cell–specific EVs were isolated for western blot and adoptively transferred into naïve mice to examine their function. Data were analyzed using t-tests.
Results: ASC GFP fluorescence was increased in the hearts of CCI versus sham at 2 months. IL-1β was activated in cardiac endothelial cells and primed in cardiac macrophages at 7 months after injury (p < 0.05). Although hCD63-GFP+ EVs were detected from all brain cell types of origin, only microglial EVs trafficked to the heart, and these were significantly increased in the heart at 2 months after CCI (p < 0.05). Microglial EVs contained increased IL-1β after CCI, and induced accumulation of IBA1+ cells in the brain and heart in naïve mice at 24 hours after adoptive transfer (p<0.05).
Conclusion: After TBI, microglial EVs traffic to the heart and promote cardiac inflammation via IL-1β. The data are the first to identify microglia-specific EV brain-heart communication and overcome a significant limitation of defining cell specificity in the EV field.
Impaired Intraspinal Hemodynamics and Neurovascular Unit in the Chronically Injured Spinal Cord
1University of Louisville, Louisville, United States, 2University of Washington, Seattle, United States
Vascular disruption and remodeling at the injury epicenter after spinal cord injury (SCI) are well documented, however, whether these changes extend caudally remain unclear. A study suggested that spinal cord oxygenation below a chronic injury is reduced to 40% of preinjury levels. We hypothesize that intraspinal hemodynamics and vascular associated cells are altered caudal to the injury in chronic SCI. We examined intraspinal blood flow using contrast enhanced ultrasound imaging at L3 in rats with chronic SCI at T8/9. We found that while a moderate injury did not show significant alterations in vascular resistance (GM: p=0.582 and WM: p=0.43), a severe SCI resulted in a significantly elevated vascular resistance in both GM (p=0.023) and WM (p=0.017) compared to baseline. Interestingly, vascular response during a metabolic challenge was reduced (27-34%) in both groups compared to sham. Cellular analysis revealed preserved pericyte coverage after moderate injury but was significantly reduced after a severe SCI (p<0.0005). Serotonergic innervation was reduced in both injury (p=0.001). While microglial activation increased across both severities, astrocyte density remained unchanged. Importantly, increased vascular resistance was highly correlated with both spared serotonin percentage (r=-0.712; p=0.002) and pericyte loss (GM: r= -0.856; p=0.144; WM: r= -0.575, p= 0.425). These findings indicate that SCI leads to significant intraspinal vascular dysfunction and cellular alterations below the injury site in an injury severity dependent manner. This study highlights the potential of targeting the neurovascular unit to restore blood flow thereby enhance functional recovery below the injury.
Implantable Flexible Head-Mounted Circuit Interface for Neural Recording and Stimulation in Freely Moving Spinal Cord–Injured Mice
Dr. Ahnsei Shon1, Dr. Wei Wu1
1University Of Louisville, Louisville, United States
Rigid headstages add mechanical load that can alter behavior and introduce movement artifacts, a particular issue in mouse SCI studies. Many available systems are also designed for acute anesthetized experiments, limiting chronic recordings during locomotion. We developed a low-profile, implantable flexible head-mounted interface that supports multi-channel neural recording and electrical stimulation in freely moving SCI mice. The device is built on a conformable flexible PCB that follows cranial curvature and uses a lightweight tether to place amplification off-head, reducing cranial load while maintaining signal quality. A modular design allows recording and stimulation concurrently without hardware changes and accommodates different electrode layouts for chronic studies. During treadmill locomotion, SCI mice showed stable neural recordings over 5 weeks with 4 channels. Stimulation reliably evoked hindlimb EMG responses and synchronized high-speed kinematics enabled alignment of EMG activity with stimulation-evoked movements. This platform enables chronic, behaviorally relevant interrogation of circuit changes after SCI and supports closed-loop neuromodulation experiments in mice.
Implementation of a Microglial Replacement Procedure in a Rat Model of Mild-to-Moderate Traumatic Brain Injury
1Traumatology Unit, French Armed Forces Biomedical Research Institute, Brétigny-sur-Orge, France, 2Neurophysiology of Stress Unit, French Armed Forces Biomedical Research Institute, Brétigny-sur-Orge, France, 3Biological Analyses Unit, French Armed Forces Biomedical Research Institute, France
Traumatic brain injury (TBI) induces persistent activation of brain microglia, which is strongly associated with the development of chronic neurological deficits. Microglial replacement, defined as the pharmacological elimination of microglia followed by spontaneous repopulation after treatment withdrawal, has emerged as a promising strategy to restore neuroimmune homeostasis after TBI. While this approach has been extensively studied and characterized in mice, its translation to rats, a preclinical model widely used in TBI research, remains challenging. Here, we evaluated several microglial replacement procedures in adult male rats. Microglial elimination was induced using PLX5622, a colony-stimulating factor-1 receptor inhibitor, and microglial density was quantified in brain samples by flow cytometry. In naive animals, a 12-day oral treatment (1,200 ppm in chow) failed to induce effective microglial elimination, consistent with previous reports. By contrast, a 7-day intraperitoneal treatment (60 mg/kg, twice daily) resulted in significant depletion (−80.85±8.18% compared to untreated animals, p=0.030; n=4/group). This protocol was subsequently applied to a mild-to-moderate lateral fluid-percussion rat model of TBI. Microglial elimination remained significant in injured animals (−36.16±21.63% compared to untreated animals, p=0.005; n=6/group) but was less pronounced than in naive animals. Three weeks after treatment withdrawal, microglial repopulation was nearly complete. However, density of activated microglia remained relatively high in TBI animals even after replacement. Hence, these findings demonstrate the feasibility of microglial replacement in adult male rats. Future studies will aim at characterizing the phenotype of repopulated microglia in rats exposed to TBI. This work was funded by the French Ministry for Armed Forces.
Implementation of a Standardized Framework to Mitigate Challenges in Imaging Repository Organization for Large Multisite Studies
Mr. Theodore Tran1,2,3,
1Department of Neurological Surgery, University of California, San Francisco, San Francisco, United States, 2Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital, San Francisco, United States, 3Weill Institute for the Neurosciences, University of California, San Francisco, San Francisco, United States, 4Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, United States
Noncontrast head computed tomography (CT) is the primary modality to diagnose traumatic brain injury (TBI). However, a standardized process to upload and store CT images across multiple trauma centers has yet to be implemented, limiting analysis in multicenter research. This study presents a standardized workflow to identify and upload CT scans across research sites in a longitudinal, prospective cohort study.
The TRACK-TBI Study (ClinicalTrials.gov #NCT02119182) enrolled patients presenting to 18 United States trauma centers who received a head CT within 24-hours post-TBI and aimed to collect and upload all inpatient noncontrast head CT scans onto an imaging repository (Flywheel, https://flywheel.io, Minneapolis, Minnesota, USA). Five TRACK-TBI sites were provided with a standardized protocol to identify CT scans completed but missing from Flywheel. Sites uploaded the first four sequential noncontrast head CT scans for enrolled patients using a standardized identifier, specifying the site, de-identified subject ID, and session number, ensuring chronological ordering and traceability.
Across 608 patients, 694/1138 scans (556 second, 355 third, and 227 fourth scans) were reconciled and uploaded. Missing scans can be attributed to limitations accessing scans in medical records and data entry errors.
Differences in imaging repository practices highlight the need for a standardized process when consolidating imaging data across institutions to create a reproducible, high-quality imaging dataset that facilitates accuracy, precision, and efficacy of contemporary, multicenter neuroimaging curation and analyses. Our imaging repository workflow establishes the foundation for downstream research applications, including critically needed identification and modeling of complex intracranial pathology to meaningfully improve TBI diagnosis and prognostication.
Inhibition of ADAM17 and Cerebrovascular Reactivity Following Exposure to Repetitive Low-Level Blast
1Naval Medical Research Command, Silver Spring, United States, 2Henry M Jackson Foundation, Rockville, United States
Military personnel face significant health risks from repetitive low-level blast (rLLB) exposure, which can cause long-term neurological damage. This study investigated the link between rLLB, cerebrovascular dysfunction, neuroinflammation, and tested a treatment targeting TNF-α production in an established rat model of rLLB. Rats were exposed to a single 5.6 psi blast overpressure for 15 days. Following exposure, half of the subjects received an ADAM17 inhibiting drug that blocks TNF-α production for 7 days after the last blast exposure. Using intravital microscopy, we assessed functional responses of the pial microvasculature to vasodilating (CO2) or vasoconstricting (BaCl2 and serotonin) agents one day (1d) after treatment. Analyses of small- (<50µm) and medium- (50-100µm) sized vessels responses revealed that rLLB exposure dysregulated responsiveness. In animals exposed to rLLB, small vessels exhibited increased vascular reactivity to CO2 and BaCl2. Blast exposure significantly increased BaCl2-induced vasoconstriction in small vessels; however, this effect was reduced with drug treatment. Medium vessels in blast-exposed animals exhibited significant constriction following CO2 exposure. Analyses of cortical tissue demonstrated that ADAM17, Aβ40 and 42 levels remained unaffected by blast exposure and treatment, while phospho-tau levels decreased with blast exposure and were lowest in blast-exposed animals treated with the drug. These findings indicate that rLLB is injurious to small pial vessels in the early phase following rLLB and that pharmacological inhibition of ADAM17 may mitigate blast-induced injury, and restore vascular integrity. Further studies on the effects of rLLB and ADAM17 inhibition on neurodegenerative markers are indicated.
Inhibition of TACE Following Repetitive Low-Level Blast Exposure Impacts Cytokine Expression and Neurodegeneration
1Henry Jackson Foundation, Bethesda, United States, 2Naval Medical Research Command, Silver Spring, United States
Service members (SMs) are frequently exposed to low-level blasts in both combat and training operations. While these repeated low-level blasts (rLLBs) often lack overt concussion, there is increasing evidence suggests that damage accumulates over time to create persistent neurological deficits, including neuroinflammation. This study examined the effects of a TNF-α converting enzyme (TACE) inhibitor as treatment after rLLB exposure. We exposed rats to a 5.6 psi blast overpressure (BOP) for 15 days, then injected a TACE inhibitor for 7 days beginning after the final blast exposure. Cytokine levels and neurodegenerative markers were measured in the frontal cortex at 1 day, 7 days, and 30 days post-treatment. The levels of IL-1β were elevated in animals treated with the inhibitor at 1, 7 and 30 days post-treatment, with the highest levels observed at 7-days. IL-6 levels in animals treated with the inhibitor were also increased at 7-day post treatment. No differences in TNF-α expression were seen at any of the timepoints measured. Despite the increase in inflammatory cytokines, animals treated with the inhibitor showed decreased levels of phosphorylated tau (p-tau), and Aβ-40 at 7 days post-treatment, and decreased levels of p-tau, Aβ-40, and Aβ-42 at 30 days post-treatment. While the inhibitor was not shown to affect TNF-α levels in the frontal cortex, inflammatory cytokines and neurodegenerative markers were still being impacted. The observed reduction in neurodegenerative markers with concomitant increase in cytokines with treatment suggests the drug may modulate the levels of neurodegeneration markers via mechanisms other than reduction in neuroinflammatory cytokines.
Inhibition of the RNA Regulator HuR potently mitigates TBI by suppressing post-injury neuroinflammation
1University Of Alabama at Birmingham, Birmingham, United States
Within minutes after traumatic brain injury (TBI), microglia and astrocytes become activated and produce inflammatory mediators such as IL-6, IL-1β, TNF-α, iNOS and COX-2 which promote secondary tissue injury through cytotoxicity, vascular hyperpermeability, edema, and secondary ischemia. This inflammatory cascade is further amplified by chemokines that promote recruitment of peripheral immune cells. Many inflammatory mediators are post-transcriptionally regulated via AU-rich elements in their 3′ UTR. HuR is an RNA regulator that binds to these regions and promotes RNA stability and enhanced translational efficiency. We have developed a small molecule inhibitor, SRI-42127, that blocks HuR function by preventing its homodimerization. This study sought to determine whether SRI-42127 could blunt secondary neuroinflammatory responses after TBI and improve outcome. Briefly, TBI was induced in mice using an open head injury to the dorsal hippocampus and posterior sensorimotor cortex. After a TBI, mice received SRI-42127 or vehicle intraperitoneally and Inflammatory mediators were measured in brain tissue and blood by qPCR, ELISA, immunohistochemistry, and western blot. Behavioral testing was performed to assess functional outcomes including motor recovery and memory.
With SRI-42127 treatment, there was significant improvement in fine motor function and spatial memory compared to vehicle controls. Pro-inflammatory mediators in the injured brain were blunted by ∼60-80%. Moreover, SRI-42127 potently reduced microglial and astrocyte activation, neuronal loss and cortical lesion size. In summary, our findings show that HuR inhibition with SRI-42127 suppresses acute pro-inflammatory responses after TBI and improves functional outcome.
Institutional ICU Admission Criteria in Traumatic Brain Injury Patients: A TRACK-TBI Survey Study
1Department of Neurology, University of Wisconsin – Madison, 2Department of Neurological Surgery, University of Wisconsin – Madison, 3Department of Neurology and Rehabilitation Medicine, University of Cincinnati, 4School of Medicine and Public Health, University of Wisconsin – Madison, 5Department of Neurology, University of Pennsylvania, 6Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania, 7Department of Neurological Surgery, University of California, San Francisco, 8Department of Neurosurgery, University of Washington, 9Department of Neurological Surgery, University of Pittsburgh
Introduction: For patients with acute TBI, intensive care unit (ICU) admission criteria are not well defined. U.S. institutions vary considerably, and the range of practice is uncertain.
Objective: Evaluate institutional ICU admission criteria in acute TBI.
Methods: Surveys on institutional practice were sent to site PIs and ICU providers at 18 sites in the TRACK-TBI U01 study. Surveys were returned by 27 providers from 16 sites (88% site response) between 2020-2021 with a secondary round in 2024 to capture additional sites. 10 responses were from intensivists and 17 responses were from neurosurgeons.
Results: The most common admission destination for TBI ICU patients was a neurosciences ICU (52% of responses) or a dedicated neurotrauma unit (28%). There was agreement that GCS ≤ 8 always prompted ICU admission (96%). GCS 9-12 without CT abnormalities was always an indication for 40% of respondents. GCS 13-15 with CT abnormalities but no large structural lesion was always an indication in 40% of respondents and not an indication for admission in 20%. GCS 13-15 while on anticoagulation (AC) or antiplatelet (AP) therapies without CT abnormalities was possibly an indication in 60% (AC)/52% (AP), not an indication in 32% (AC)/40% (AP), and always an indication in 8% (AC)/8% (AP).
Conclusion: Despite agreement that patients meeting criteria for severe brain injury should be admitted to the ICU, substantial institutional differences exist in ICU admission criteria for patients with smaller lesions or who are on AC/AP without CT abnormalities.
Instrumented Mouthguard-Derived Biomechanical Severity Measures Associated with Head Injury Assessments in Elite Australian Football
James Hickey1, Becca Xie1, Jonathan Reyes1,2, Lauren Evans1, William O’Brien1, Kate Gillespie-Jones2, Lauren Giesler1, Sandy Shultz1, Terence O’Brien1,3, Biswadev Mitra1,3, Michael Makdissi2, Catherine Willmott1,2,
1Monash University, Melbourne, Australia, 2Australian Football League, Melbourne, Australia, 3Bayside Health, Melbourne, Australia
Instrumented mouthguards capture head kinematics in sport and may help identify impacts requiring head injury assessment (HIA), but optimal biomechanical severity measures remain unclear. Elite Australian football provides a high-quality benchmark, with HIA triggers guided by doctors using live observation and video review. We compared mouthguard-derived measures between impacts associated with HIA and impacts not requiring assessment (no-HIA), and between diagnosed concussion and no-HIA impacts.
Across four seasons, 424 men and 487 women wore HIT-IQ mouthguards. Impacts resulting in HIA were video-matched to mouthguard data and compared with a subset of no-HIA impacts. Measures included peak linear acceleration (PLA), peak rotational acceleration (PRA), peak power, diffuse axonal multi-axis general evaluation (DAMAGE), and head acceleration response metric (HARM). Area under the curve (AUC) assessed discrimination, and DeLong’s test compared AUCs.
In men, 41 HIAs (17 concussions, 24 medically cleared) and 754 no-HIAs were analysed. HARM best discriminated HIA from no-HIA impacts (AUC=0.95, 95%CI: 0.91–0.99), outperforming other measures (P<0.05), and concussive from no-HIA impacts (AUC=0.98, 95%CI: 0.96–1.00). In women, 74 HIAs (10 concussions, 64 medically cleared) and 1308 no-HIAs were analysed. Peak power had highest HIA versus no-HIA AUC (AUC=0.90, 95%CI: 0.87–0.93), outperforming PLA and PRA (P<0.05). Peak power and PLA had highest concussive versus no-HIA AUCs (AUC=0.96 each).
Instrumented mouthguard-derived biomechanical severity measures discriminated no-HIA impacts from those resulting in an HIA or diagnosed concussion in elite Australian football. Further work should determine optimal metrics and thresholds for screening across men’s and women’s competitions and sporting levels with varying medical resources.
Insulin Treatment Alters Protein Expression and Actigraphy Levels after TBI
1USUHS, Bethesda, United States, 2HealthPartners Neuroscience Center, St Paul, United States
Traumatic Brain Injury (TBI) is an unfortunate occurrence for many military personnel participating in current conflicts. Although few treatments show clear promise of ameliorating sequalae of TBI, insulin shows promise to improve multiple symptoms. To test the effect of insulin improving TBI outcomes using a gyrencephalic animal, we delivered this drug to ferrets who received a combination of blast and CHIMERA (Closed Head Injury Model of Engineered Rotational Acceleration) injuries. After TBI, each ferret received insulin or saline intranasally for 5 days. Groups of animals included Shams and Injured, with and without insulin; animals also participated in several behavioral tests. After a 5-week survival, we evaluated the brain for a number of features, including expression of related proteins by western blot. Although all the behavioral assessments showed a clear effect of injury, treatment with insulin did not result in behavioral improvement except for actigraphy (a measure of sleep), which showed significant reductions in overall activity in the injured animals. When we studied different brain regions to assess protein expression levels (hypothalamus, anterior cingulate and the posterior temporal lobe – including the hippocampus), both the injury and insulin treatment resulted in altered expression from the Sham animals. TBI lead to increases of protein expression for the hippocampus, which was decreased toward normal with insulin, especially phosphorylated tau and phosphorylated Akt. The anterior cingulate, did not consistently show protein expression increases after TBI. Although our results are mixed regarding potential improvements with insulin treatment, the protein expression alterations are hopeful.
Interleukin 6–Mediated Disruption of Neuronal Adrenergic Signaling during Mild-to-Moderate Traumatic Brain Injury
1University of Texas Rio Grande Valley, Edinburg, United States, 2University of South Florida, Tampa, United States
Traumatic brain injury (TBI) is a neuroinflammatory disease accompanied by overexpression of pro-inflammatory cytokines. It is known that the blood concentration of interleukin-6 (IL-6) is significantly elevated in patients with TBI months after injury, indicating persistent neuroinflammation. However, the effects of the elevated concentration of IL-6 on neuronal adrenergic receptors (ARs), which regulate neurotransmission and cognitive functions, is not known. We hypothesize that prolonged IL-6 signaling induces maladaptive regulation of neuronal ARs via the inflammatory-adrenergic signaling crosstalk, and that this disruption of adrenergic signaling is in part responsible for the cognitive deficit seen during TBI. A cortical contusion injury (CCI)-induced model of mild-to-moderate (m-m) TBI was generated in C57BL/6 mice. Tissue samples collected 2 weeks after CCI revealed that injured mice had an increased level of IL-6, demonstrated with ELISA (blood) and with immunohistochemistry (brain). The direct effect of IL-6 (0.03ng/ml) on AR alpha-1A (ADRA-1A) expression in primary cortical neurons was evaluated in the presence or absence of its soluble receptor subtype - sIL-6Rα (100ng/ml overnight). Western Blot analysis demonstrated that treatment with IL-6 or sIL-6Rα alone significantly increased neuronal expression of ADRA-1A. Interestingly, combined treatment of neurons with both IL-6 and sIL-6Ra attenuated the increase of neuronal ADRA-1A expression. These findings suggest that the IL-6 interaction with sIL-6Rαmay trigger a compensatory mechanism that normalizes ADRA-1A expression. Together, these findings provide the first evidence of IL-6- adrenergic crosstalk in neurons and support a novel mechanism by which inflammation may disrupt adrenergic signaling and contribute to cognitive dysfunction seen during m-mTBI.
Intimate Partner Violence and Traumatic Brain Injury Were Associated with Increased Maternal Morbidities During Pregnancy
1University of Michigan Concussion Center, Ann Arbor, United States, 2New York University New York University Grossman School of Medicine, New York, United States, 3University of Arizona College of Medicine-Phoenix, Phoenix, United States
Background: Physical intimate partner violence (IPV) frequently targets the head, neck, and face, which puts individuals at-risk for traumatic brain injury (TBI). Estimates suggest that 60–90% of IPV co-occurs with TBI and pregnancy represents a critical period of vulnerability for both maternal and infant health, during which individuals are already at-risk for health complications. Yet the impact of IPV and TBI on maternal morbidity during pregnancy remains poorly characterized.
Methods: We conducted a retrospective cohort study using hospital discharge data from the Arizona Department of Health Services (2018–2023). Among pregnancies with a hospital encounter, pregnancies were categorized as control (no IPV or TBI; n=6,864), IPV (n=803), TBI (n=197), or IPV+TBI (n=50). Unadjusted logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for diagnostic categories grouped by ICD-10 chapters.
Results: IPV and TBI exposure during pregnancy were associated with increased odds of neurological and psychiatric diagnoses compared to controls. The strongest associations were observed for substance-related disorders, anxiety/behavioral symptoms, seizure/headache symptoms, and central nervous system-related symptoms, with the highest odds generally seen among pregnancies with IPV+TBI. Beyond neurological outcomes, IPV and TBI were associated with increased odds of multisystem morbidity, including gastrointestinal, respiratory, and musculoskeletal conditions, as well as pregnancy-related complications, particularly hemorrhagic and placental disorders.
Conclusions: Both IPV and TBI were associated with multisystem maternal morbidities during pregnancy. These data underscore the need for improved screening and integrated clinical care in this vulnerable population.
Intranasal Administration of Retinoic Acid Nanoparticles Improves Behavioral Outcomes and Brain Pathology in Mice with Repetitive Mild TBI
Dr. Michael Gower1,2
1Columbia VA Medical Center, Columbia, United States, 2University of South Carolina, Columbia, United States
Background: Repetitive, mild traumatic brain injury (TBI) leads to persistent neurological symptoms driven by axonal damage and chronic neuroinflammation, yet no drug therapies exist. All-trans retinoic acid (ATRA) may benefit mild TBI, as it improves symptoms and reduces brain injury in mouse models of Parkinson’s and Alzheimer’s disease. However, because ATRA acts through widely expressed nuclear receptors, systemic delivery can cause significant side effects. To address this, we are developing polymer nanoparticles to enhance ATRA delivery to the brain while reducing off-target exposure.
Methods: ATRA-loaded nanoparticles (ATRA-NP) were produced using nanoprecipitation. Mice underwent sham or repetitive, mild TBI consisting of 20 closed-head impacts (one per day for 20 days). Object location memory was assessed before injury and at 1, 45, and 90 days post TBI. Gait was analyzed using Palmreader software (BlackboxBio). Beginning 45 days post TBI, mice received intranasal ATRA-NP every three days until day 90; control TBI mice received “empty” nanoparticles. At day 90, brains were examined histologically.
Results: TBI produced progressive deficits in object location memory at days 45 and 90 and caused gait abnormalities marked by front-paw dragging. ATRA-NP treatment restored object location performance and improved gait at day 90. Histology revealed that TBI-induced axonal damage and increased microglia and astrocyte content in the cortex and optic tract were reduced following ATRA-NP treatment.
Conclusion: In a repetitive, mild TBI model, intranasal delivery of ATRA via nanoparticles improves behavioral outcomes and is associated with reduced neuroinflammation and axonal pathology.
Intranasal Delivery of Small Extracellular Vesicles Derived from Human Adipose Tissue Is a Potential Therapy for Traumatic Brain Injury
1University of South Florida, Tampa, United States, 2James A Haley VA Hospital, Tampa, United States
Traumatic brain injury (TBI), caused by rapid acceleration, deceleration, or impact, affects over 2 million individuals annually in the United States. Despite its prevalence, effective therapeutic interventions remain limited. To address this gap, our lab investigates small extracellular vesicles (sEVs) derived from human adipose stem cells (hASC) as a potential treatment for TBI. Prior studies, including our own, have demonstrated that sEV administration 48 hours post-injury improves motor and cognitive outcomes. Here, we aim to extend the therapeutic window to seven days post-injury, a clinically relevant time point given delays in patient treatment. We also assess sex-specific responses, as biological differences may influence injury progression and therapeutic efficacy. To model TBI mice were anesthetized and receive either sham surgery (controls) or a controlled cortical impact. Baseline motor asymmetry was measured using the elevated body swing test (EBST), and animals were evenly distributed into four groups: Sham+PBS, Sham+sEV, TBI+PBS, and TBI+sEV. Mice received intranasal administration of either sEVs or PBS at seven days post-injury. Behavioral and cognitive assessments (EBST, NO/NP, and RAWM) were conducted pre- and post-injury. Immunohistochemistry and digital PCR was used to assess molecular and immune responses, focusing on sex- and treatment-dependent effects. Our findings demonstrate that sEV treatment at seven days post-injury significantly improves motor and cognitive function and reduces brain injury in both male and female mice, supporting an extended therapeutic window for TBI intervention.
Intranasal Hypocretin Reorganizes Glia-Neuron Microcircuitry After Traumatic Brain Injury
1Department of Integrative Physiology, University of Colorado, Boulder, United States, 2The University of Glasgow, Glasgow, Scotland, 3Stanford University School of Medicine, Palo Alto, United States
Sleep-wake dysfunction is a persistent and debilitating consequence of TBI. Although hypocretin (HCRT) neurons are critical for arousal stability, prior work and our findings demonstrate that TBI does not reduce total HCRT neuron number. In contrast, TBI leads to sleep fragmentation, evidenced by increased sleep-wake transitions (p<0.05), suggesting that post-traumatic dysfunction arises from circuit-level remodeling rather than neuronal loss. We tested whether restoring HCRT signaling during the acute post-injury window can reverse injury-induced structural and neuroimmune alterations within the HCRT system.
Adult mice (n=64) underwent focal TBI using controlled cortical impact or sham surgery and received intranasal saline or HCRT on days 1–3 post-injury. Quantitative morphometry and spatial analyses were performed at 3 and 7 days post-injury. TBI did not affect the total number of HCRT neurons in the lateral hypothalamus but significantly increased HCRT neuron soma perimeter (p<0.05), indicating structural remodeling in the absence of degeneration. Intranasal HCRT partially normalized these injury-induced morphological changes.
At the microenvironment level, TBI significantly disrupted astrocyte and microglial process organization surrounding HCRT neurons (TBI × treatment effects, p<0.05). Sholl-based spatial analyses revealed that intranasal HCRT significantly modulated these injury-induced changes, shifting glial process intersections toward a more organized, treatment-dependent pattern.
Together, these findings indicate that post-traumatic sleep-wake instability emerges from dynamic glia-neuron remodeling of the hypocretin arousal network. Importantly, this circuit remains structurally plastic in the acute post-injury period, and intranasal hypocretin can engage and reorganize the injured glial microenvironment, identifying a potential therapeutic strategy for restoring arousal stability after TBI.
Investigating Cellular Senescence in Serotonergic Pain Modulation Following Traumatic Brain Injury
1Loyola University Chicago - Neuroscience Program, Maywood, United States, 2Edward Hines Jr. VA Research and Development Services, Hines, United States, 3Loyola University Chicago Burn and Shock Trauma Research Institute, Maywood, United States, 4Loyola University Chicago Medical Center, Stritch School of Medicine, Maywood, United States, 5Loyola University Chicago Medical Center, Department of Anesthesiology and Perioperative Medicine, Maywood, United States, 6Edward Hines Jr. VA Hospital, Surgical Services, Hines, United States, 7Loyola University Chicago, Department of Molecular Pharmacology and Neuroscience, Maywood, United States, 8Loyola University Chicago Medical Center, Department of Otolaryngology, Head and Neck Surgery, Maywood, United States
Approximately one in four people will experience mild traumatic brain injury (mTBI)-induced chronic pain over their lifetime. Cellular senescence is a proinflammatory cell cycle arrest implicated in nerve injury-induced chronic pain models and in the persistent symptoms of mTBI. Elimination of senescent cells with senolytic drugs has proven beneficial in both paradigms. This study investigated the therapeutic potential of the senolytic drug ABT-263 in mTBI-induced chronic pain and cellular senescence. Rats received 5 mTBIs spaced 48 hours apart. Mechanical and thermal sensitivity were measured using the von Frey and Hargrave’s tests, respectively. Rats displayed increased sensitization at 3, 7, 14, and 49 days post-injury (DPI). At 35 DPI, a subset of mTBI animals received a single intraperitoneal injection of ABT-263, which ameliorated both mechanical and thermal sensitization by 49 DPI. Lumbar spinal cords were then harvested and immunolabelled for senescence and cell type-specific markers to characterize senescent cell types in the spinal cord dorsal horn (SDH) following TBI. Studies have also implicated altered serotonin signaling in the SDH as a potential cause of mTBI-induced diffuse noxious inhibitory control dysregulation. Here, we investigated the impact of SDH cellular senescence and senolytic treatment on serotonin signaling and localization in an mTBI model of chronic pain. Lumbar spinal cords were evaluated at 14 and 49 DPI for changes in serotonergic markers after TBI and senolytic treatment. These findings provide valuable insight into the mechanisms driving rmTBI-induced chronic pain and inform the development of more effective pain management strategies.
Investigating Neuroinflammatory Signatures of Neurobehavioral and Cognitive Impairment in Traumatic brain Injury
1University Of Washington, Seattle, United States
Traumatic brain injury (TBI) is a major cause of long-term neurological and psychiatric disability and increases the risk of cognitive impairment, mood disorders, and neurodegeneration. Despite its clinical impact, the pathological mechanisms underlying these deficits remain incomplete. Emerging evidence suggests that chronic neuroinflammation—characterized by persistent microglial activation plays an important role in post-traumatic neurodegeneration. However, the spatial distribution of these inflammatory processes across functional brain networks involved in cognition and behavior remains poorly characterized. This study aimed to quantitatively assess neuroinflammatory changes across key brain networks implicated in cognitive and behavioral regulation following TBI. Postmortem brain tissue was obtained from donors with a history of TBI and documented behavioral or mixed cognitive and behavioral clinical impairment also controls without a history of TBI or impairment. Immunohistochemistry was performed on key nodes within functional networks involved in cognitive (default mode and executive control networks) and behavioral (salience and limbic networks) regulation. Whole-slide images using Aperio AT2 scanner and analyzed with HALO software. Microglial activation was quantified using IBA1 immunostaining by measuring soma density within gray matter. Quantitative analysis demonstrated cases with behavioral impairment showed elevated microglial density throughout most sampled brain regions compared with controls, with the notable exception of the hippocampus. In contrast, cases with mixed cognitive and behavioral symptoms were not significantly different from controls, although a trend toward increased inflammation was observed (p=0.09). Our findings support chronic neuroinflammation affects brain networks after TBI, but distinct networks were not clearly preferentially involved in our preliminary analyses so far.
Investigating the Impact of TBI and Diet on Gut Microbiome Dysbiosis in a Clinically Relevant Mouse Model of Cardiovascular Disease
Tiffany Veliz1, Sai Anusha Jonnalagadda2, Aayush S. Patel2, Andrew S. Paolini3, Nikki Kashani3, Donna A. Nguyen3, Dr. Mary C. Kosciuk1, Dr. Venkat Venkataraman4, Dr. Robert G. Nagele1,2,3,6, Dr. Randel L. Swanson5,
1Department of Geriatrics and Gerontology, New Jersey Institute for Successful Aging (NJISA), Rowan-Virtua SOM, Stratford, USA, 2Rowan-Virtua School of Translational Biomedical Engineering and Sciences (TBES), Stratford, USA, 3Rowan-Virtua School of Osteopathic Medicine (SOM), Stratford, USA, 4Department of Academic Affairs, Rowan-Virtua SOM, Stratford, USA, 5Department of Physical Medicine and Rehabilitation, University of Pennsylvania Perelman School of Medicine, Philadelphia, USA, 6Department of Cell Biology & Neuroscience, Rowan-Virtua SOM, Stratford, 08084.
Background: The impact of traumatic brain injury (TBI) and Western diet (WD) on gut microbiome dysbiosis is well-recognized. However, longitudinal in vivo TBI studies comprising animals maintained on a WD or high fiber (HF) diet for an extended time period are nonexistent.
Methods: Male and female LDL receptor-deficient (LDLr-KO) mice maintained on either WD (n=5) or HF (n=5) diet for eight months (age: nine months), underwent controlled cortical impact (CCI) injury on the left hemisphere (impactor diameter: 2mm, impact depth: 1mm, speed: 5m/s). Following CCI, animals were maintained on the same diet for the subacute post-CCI period, 17-18 days. Pre-injury fecal samples were collected just before CCI, while naïve and post-injury samples were collected at the time of euthanasia. Fecal samples from naïve LDLr-KO mice on regular vivarium diet (RVD) (n=3) for nine months were also analyzed. Microbiome analysis services of TransnetYX® were used for fecal sample processing, data collection, and analysis.
Results: Sangeribacter muris and Akkermansia muciniphila were the two most predominant gut bacteria in naïve mice on RVD. However, in pre-injury (naïve) WD mice, the population of S.muris is considerably reduced while A.muciniphila is dramatically increased. Following injury, A. muciniphila population remained most predominant in the WD mice. In pre-injury HF mice, S.muris was the second most predominant bacterium, and became the most predominant bacterium following injury. In some WD mice, proinflammatory bacteria, Serratia bockelmannii, Serratia marcescens, and Staphylococcus epidermis were also seen.
Conclusion: Both diet and TBI seem to play a role in gut dysbiosis.
Kinematic Analysis of Closed Head Injury in Mice Using Markerless Motion Capture Reveal Contact and Inertial Effects on Functional Outcomes
1University of California, Riverside, School of Medicine, Riverside, United States, 2Indiana University, School of Medicine, Indianapolis, United States, 3Stark Neuroscience Research Institute, Indianapolis, United States
Mild traumatic brain injuries (mTBI) result in physiological perturbations and lead to Alzheimer’s Disease and Related Dementias (ADRD) symptomology. Single closed head injury (sCHI) and repeated CHI (rCHI) can lead to cognitive disabilities long-term. We developed a mouse head tracking system and processing pipeline, employing videography with markerless motion tracking, to perform accurate kinematic measurements during CHI, aimed at investigating the contact and acceleration effects on functional outcomes. Male and female juvenile C57BL/6J mice at postnatal day 17 (p17), 8-months (8-MO), and 12-months (12-MO) of age, were subjected to sham treatment (anesthesia only), sCHI, or rCHI (n=5) using a pneumatic impactor. Kinematics were recorded with two hardware synchronized cameras. The first CHI was delivered to the left somatosensory cortex while rCHI involved a second impact to the ipsilateral prefrontal cortex 3 days (d) later. From the videography, markerless feature estimation were quantified with the deep learning neural network, DeepLabCut, and the kinematics were analyzed using MATLAB and Python. Brain volumes and bleeding were evaluated by ex vivo MRI (T2-weighted imaging, Susceptibility Weighted Imaging). Highest rotation along the frontal plane was observed in the p17 cohort. rCHI groups had increased weight and decreased righting and exploration time, immediately following injury. Whole brain volumes were lowest in 3d rCHI mice and peak bleed distribution was shifted posteriorly in all rCHI groups relative to sCHI. The study enhances our understanding of head kinematics in mouse mTBI and provides more accurate characterization and scaling of TBI events.
Lesion Topography Shapes the Spatial Clustering and Propagation of Cortical Spreading Depolarizations After Acute Brain Injury
1Hennepin Healthcare Research Institute, Minneapolis, United States
Objective: To determine whether cortical spreading depolarization (CSD) frequency and propagation patterns are structured by lesion location and lesion type in patients with acute brain injury.
Methods: Six patients undergoing subdural electrocorticography monitoring with 32-contact strip arrays were studied. CSD events were detected using a semi-automated pipeline incorporating spectral feature analysis and manual validation. Lesion location was estimated from computed tomography imaging and represented by a lesion centroid mapped to electrode space. For each electrode, distance to the lesion centroid and event frequency were calculated. For each event, first-active contacts and gross propagation direction were characterized.
Results: In five of six participants, CSD frequency decreased as distance from the lesion centroid increased, demonstrating an inverse distance–frequency relationship. In patients with focal cortical lesions (three of six participants), events clustered near the lesion and propagate outward from the lesion centroid. In contrast, patients with diffuse or distributed injury patterns demonstrated spatially widespread activation with multidirectional propagation. Temporal–parietal propagation patterns (on average 81.7% of CSDs) were commonly observed across participants. These findings were consistent despite variability in lesion size and distribution.
Conclusions: Lesion morphology strongly influences the spatial organization of CSD. Focal injury is associated with perilesional clustering and structured outward spread, whereas diffuse injury permits broader multidirectional propagation. Lesion-informed monitoring may improve interpretation of spreading depolarization burden in acute neurotrauma.
Leveraging Patient Perspectives to Improve Social Needs Screening After Traumatic Injury: A Qualitative Study
1Medical College of WI, Milwaukee, United States
Routine screening for social determinants of health (SDOH) is mandated in inpatient settings yet of unclear value to patients. To learn patient perspectives of in-hospital basic needs screening, we conducted qualitative interviews with 20 adults previously hospitalized at a Level I trauma center for traumatic injuries, including traumatic brain injury, who screened positive for one or more unmet needs. Interviews followed a semi-structured guide exploring participants’ recall, experiences, and outcomes of SDOH screening. A three-member research team conducted interviews and applied rapid qualitative analysis using structured note templates. Analysis followed the Stanford Lightning Report Method, incorporating iterative team debriefs, rapid synthesis across interviews, and thematic analysis to identify key findings. Participants generally perceived in-hospital SDOH screening as a positive and appropriate component of trauma care, though experiences varied based on timing, delivery, and follow-up. Screening conducted during acute illness or severe pain was often forgotten or perceived as routine paperwork, while screening delivered after stabilization and framed as meaningful conversation was more memorable and valued. Most participants appreciated being asked about social needs, even when assistance was not required, as it conveyed care beyond medical treatment. Perceived impact ranged from neutral to transformative. Patients with weaker personal support systems benefited most from clinically driven social services, whereas mismatched resources, unclear communication, or fragmented follow-up limited perceived value. Overall, patients viewed in-hospital SDOH screening as acceptable and worthwhile, highlighting the importance of timing, communication, and coordinated follow-up to maximize screening impact and improve social support services for trauma patients.
Liposomal Dexamethasone Delivery Reduces Neuroinflammation and Amyloid Pathology in APP/PS1 Mice Following Traumatic Brain Injury
1Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, United States, 2Department of Nanomedicine, Houston Methodist Research Institute, Houston, United States, 3Department of Neuroscience in Neurological Surgery, Weill Cornell Medical College, New York, United States
Alzheimer’s disease (AD) is a neurodegenerative disorder marked by amyloid-beta (Aβ) plaque deposition, tau neurofibrillary tangles, and persistent neuroinflammation. Traumatic brain injury (TBI) is a major environmental risk factor that can accelerate AD-related pathology, including chronic inflammation and increased Aβ accumulation, yet therapies that effectively target these post-injury mechanisms remain limited. Here, we engineered dexamethasone-loaded liposomes (Lipo-Dex) to suppress neuroinflammation in a TBI-induced AD transgenic mouse model. Moderate TBI was induced via controlled cortical impact (CCI) injury in APP/PS1 (27-32 weeks old) mice. Dynamic Light Scattering (DLS) analysis revealed that Lipo-Dex had a hydrodynamic size of 115.9 ± 4.8 nm, exhibiting a uniform size distribution. Ex vivo biodistribution analysis using IVIS confirmed that Lipo-Dex localized effectively to injured brain regions after retro-orbital injection at 1 and 7 days post-injury (dpi) in both males and females, supporting targeted delivery after TBI. Lipo-Dex reduced Iba1+ microglial activation and Aβ burden in the cortex and dentate gyrus of both male and female mice compared with Lipo-treated groups at 7 dpi. Interestingly, control male mice treated with Lipo showed greater microglial activity and Aβ deposition than control female groups. Functionally, Lipo-Dex treatment improved motor performance in female APP/PS1 mice, whereas it enhanced recognition memory in male APP/PS1 mice compared with Lipo-treated controls at 3 and 7 dpi. Collectively, these findings support Lipo-Dex as a brain-targeted, nanoparticle-based strategy to modulate neuroinflammation, amyloid pathology, and behavioral outcomes following TBI in an AD model, while highlighting the importance of sex as a biological variable for therapeutic response.
Longitudinal Magnetic Resonance Imaging Reveals Neuroprotective Effects of Combined Hydrogen-Enriched Water and Minocycline Therapy After Traumatic Brain Injury
1Ward Melville High School, Setauket, United States, 2San Marino High School, San Marino, United States, 3Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, United States, 4Department of Radiology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, United States, 5Department of Radiology, Stony Brook Medicine, Stony Brook, United States
Objective: Traumatic brain injury is a major cause of death and long-term disability, and effective neuroprotective therapies remain limited. Secondary injury mechanisms, including oxidative stress and neuroinflammation, contribute to progressive tissue damage. This study evaluated whether combination therapy with hydrogen-enriched water and minocycline improves structural and functional outcomes following experimental traumatic brain injury.
Methods: Male Sprague–Dawley rats underwent controlled cortical impact injury and were randomly assigned to vehicle control or combination therapy for 7 days. Longitudinal magnetic resonance imaging was performed at 2, 7, 14, and 30 days after injury using T2-weighted imaging and continuous arterial spin labeling to quantify lesion volume and cerebral blood flow. Sensorimotor recovery was evaluated using cylinder and foot-fault behavioral tests.
Results: Magnetic resonance imaging demonstrated significantly reduced lesion volume in treated animals compared with controls from acute through chronic stages after injury. Differences in normalized cerebral blood flow were observed during early and subacute phases, suggesting modulation of post-traumatic perfusion dynamics. Behavioral testing showed improved motor coordination and forelimb symmetry in treated animals during recovery.
Conclusion: Combined treatment with hydrogen-enriched water and minocycline reduced structural brain injury and improved functional recovery after traumatic brain injury, supporting the potential of multi-target therapeutic strategies.
Longitudinal Monitoring of Capillary Blood Biomarkers in Traumatic Brain Injury: A Dried Plasma Spot Pilot Study
Davin Jackson1, Katie Tehas1, Kristy Radeker1, Anthony DeLizza1, Caroline Popper1, Elaine Peskind2, Ava Puccio3, Raquel Gardner4, John Williamson5, Lisa Merck6,7, Geoff Manley8, Kevin Wang9,
1Gryphon Bio, South San Francisco, United States, 2Northwest Mental Illness Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, USA, 3University of Pittsburgh, Pittsburgh, USA, 4Sheba Medical Center, Tel HaShomer, Israel, 5Brain Rehabilitation Research Center, Gainseville, USA, 6Virginia Commonwealth University, Richmond, USA, 7Brown University, Providence, USA, 8University of California at San Francisco, San Francisco, USA, 9Foundation for Applied Molecular Evolution, Alachua, USA, 10Owl Therapeutics, Cambridge, USA
Background: Traumatic brain injury (TBI) increases long-term risk for cognitive decline and neurodegeneration, motivating objective blood biomarkers that can be measured repeatedly over time. However, reliance on venipuncture limits longitudinal monitoring, particularly outside clinic settings.
Objective: We conducted a pilot feasibility study comparing fingerstick capillary blood collected as dried plasma spots (DPS) with matched venous EDTA plasma for quantification of glial fibrillary acidic protein (GFAP) and neurofilament light (NfL).
Methods: Paired samples were collected prospectively across matched time points spanning hours to decades post-injury and assayed using high-sensitivity immunoassays. We further evaluated the GFAP/NfL ratio as an internal, sample-based normalization strategy for improved concordance between capillary DPS and venous plasma compared with either analyte alone.
Results: Absolute protein recovery from DPS was lower and more variable than venous plasma, but paired GFAP and NfL measurements remained well-correlated. Importantly, the GFAP/NfL ratio dramatically improved the correlation between capillary and venous plasma (Pearson R2 = 0.91; Spearman r = 0.78) by acting as an internal normalization mechanism; effectively correcting for poor blood collections and differing recovery rates.
Conclusions: These results support the feasibility of minimally invasive capillary microsampling for longitudinal neurotrauma biomarker monitoring and suggest that ratio-based normalization may mitigate collection-related variability. Larger prospective studies are needed to validate performance across injury severities and settings, and to define stability and cost-effectiveness for ambient-temperature shipment. If confirmed, capillary DPS sampling could reduce biosampling burden and expand access to biomarker-informed decision-making across prehospital, acute, and post-acute TBI care and related neurodegenerative conditions.
Longitudinal Pain Intensity and Interference Symptomatology in Moderate-Severe Traumatic Brain Injury: A TRACK-TBI Study Across 12-Months Post-Injury
1University of California, San Francisco, San Francisco, United States, 2Brain and Spinal Injury Center, Zuckerberg San Francisco General Hospital, San Francisco, United States, 3Weill Institute for the Neurosciences, University of California, San Francisco, San Francisco, United States, 4Departments of Neurological Surgery and Biostatistics, University of Washington, Seattle, United States, 5Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, United States, 6University Neurosurgical Center Holland, Leiden University Medical Center, Haaglanden Medical Center, Leiden, The Netherlands, 7Department of Neurological Surgery, Medical College of Wisconsin, Milwaukee, United States, 8Department of Neurological Surgery, University of Wisconsin-Madison, Madison, United States, 9Department of Emergency Medicine, University of California, San Francisco, San Francisco, United States, 10Department of Neurology, University of California, San Francisco, San Francisco, United States, 11Department of Emergency Medicine, University of Michigan, Ann Arbor, United States, 12School of Public Health Sciences, University of Waterloo, Waterloo, Canada, 13Department of Rehabilitation Medicine, University of Alberta, Edmonton, Canada, 14Philip R. Lee Institute for Health Policy, University of California, San Francisco, San Francisco, United States, 15Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas, United States, 16Department of Neurological Surgery, Baylor College of Medicine, Houston, United States, 17Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Charlestown, United States
Approximately 50% of moderate-severe traumatic brain injury (msTBI) patients report chronic pain. Pain subtypes, risk factors, and symptom progression are poorly understood. We evaluated pain intensity and interference with daily function in a prospective longitudinal msTBI cohort.
The TRACK-TBI Study (2014-2018) enrolled patients presenting to 18 United States Level 1 trauma centers who received head computed tomography (CT) within 24-hours of TBI. Subjects aged ≥17-years with arrival Glasgow Coma Scale (GCS) 3-12, Marshall CT Score 2-4, completion of PROMIS-Pain Intensity and Interference measures, and without major extracranial injury (AIS>3) or significant pre-injury pain were included. Pain Intensity/Interference T-scores (reported mean±SD) were evaluated using mixed-effect linear regressions with β-values and [95% CIs] reported.
In 97 subjects, mean age=35.1±15.4-years, male=78%, and White/Caucasian=77%. Sixty percent were GCS 3-8 on arrival and 58% had extracranial injuries. Compared with GCS 3-8 subjects, GCS 9-12 subjects had elevated pain intensity at solely 12-months post-injury (β=+5.2[0.5-9.9], p=0.030). Covariates associated with higher pain intensity and interference, respectively, included age (per+10 years: β=+0.9[0.3,4.5], p=0.003; +0.7[0.2,1.2], p=0.011), education (per+4 years: β=-2.5[-3.8,-1.1], p=0.001; -1.8[-3.0,-0.6], p=0.004), and presence of extracranial injuries (yes vs. no: β=+2.7[0.3,5.2], p=0.029; +3.1[0.9,5.3], p=0.006). Pain intensity T-scores improved over time in GCS 9-12 (2-wk/3/6/12-months, mean±SD: 57.3±7.3; 46.0±11.4; 44.7±10.5; 44.2±10.8) but not GCS 3-8 patients (2-wk/3/6/12-months: 54.2±9.1; 43.2±9.5; 43.9±10.4; 48.1±12.3).
Improvement of pain intensity over 12-months post-injury significantly differed between GCS 3-8 and 9-12 cohorts. Our findings underscore the importance of developing mechanism- and intracranial pathophysiology-based diagnostic and therapeutic options for earlier interventions in msTBI patients with extracranial injuries.
Long-Term Effects of Blast-Induced Traumatic Brain Injury on Glial Activation and Blood–Brain Barrier Integrity
1Spinal Cord and Brain Injury Research Center (SCoBIRC), Lexington, United States, 2Department of Biomedical Engineering, Lexington, United States, 3Department of Physiology, University of Kentucky, Lexington, United States, 4 Lexington VA Healthcare System, Lexington, United States
Blast-induced traumatic brain injury (bTBI), caused by high-pressure shockwaves, is common among military personnel and can lead to long-term neurological complications, including post-traumatic epilepsy (PTE). The mechanisms driving PTE or chronic myoclonic activity after bTBI are not fully understood, but disruption of the blood-brain barrier (BBB) is a known consequence of bTBI and may play a role in post-trauma seizure development. To this end, there is a need to characterize chronic neuropathology after bTBI. Our hypothesis is that BBB disruption occurs chronically after bTBI and this pathology will correspond with myoclonic burden.
Adult male and female Sprague Dawley rats were exposed to either mild (∼11psi; n=30) bTBI, moderate (∼21psi; n=30) bTBI or sham procedures (n=12). Four months after injury, seizure burden was assessed using piezoelectric monitoring cages. Brains were then collected and processed for immunofluorescence (IF) staining to detect aquaporin 4 (AQP4), endothelial antigen SMI-71, and Prussian Blue as markers of BBB disruption. We also perform IF staining of glial fibrillary astrocytic protein (GFAP) and IBA1 to evaluate glial activation and neuroinflammation. The tissue will be scanned via ZEISS Digital Slide Scanner Axioscan and analyzed using HALO to compare the stain area and intensity in various brain regions. Statistical analysis, including t-test and pearson correlation tests, will be conducted to examine pathological differences between the bTBI and sham groups. Ongoing analyses will determine whether long-term BBB and glial pathology is associated with seizure burden and injury severity, providing insight into how bTBI may contribute to the development of PTE.
Low Pressure Hydrocephalus After Traumatic Brain Injury: A Case series and Literature Review
Mr. Henry Beckett1,
1University of Cincinnati College of Medicine, Cincinnati, United States, 2Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, United States
Low pressure hydrocephalus (LPH) is an underappreciated pathology in which patients present with ventriculomegaly and intracranial pressures (ICP) below normal, making traditional pressure-driven cerebrospinal fluid diversion treatment strategies challenging. LPH has been observed in patients after traumatic brain injury (TBI), however, its presentation and risk factors for development remain unclear. Thus, we sought to compile patients from our institution and the literature to characterize LPH after TBI. Eleven patients were identified from our institutional chart review. Additionally, we performed a scoping review using PRISMA guidelines, which yielded 6 publications, resulting in a total of 43 patients with LPH after TBI (mean age 38.42 years, 86.1% male). Patients underwent an average of 4.19 (SD 2.78) neurosurgical procedures prior to LPH diagnosis and required an average VPS valve pressure setting of 39.1mmH2O (SD 21.14). Mean Glascow Outcome Scale-Extended (GOS-E) score at 2-6 months post-shunt was 3.16 (SD 1.57), indicating lower-severe disability and a 17.1% mortality. To our knowledge, this is the largest curation of TBI patients with LPH to date. We found that patients affected by LPH after TBI are often young to middle-aged and undergo multiple neurosurgical procedures prior to LPH diagnosis. Outcomes are poor with significant long-term disability and mortality. Clinicians should consider LPH diagnosis in TBI patients with hydrocephalus, especially if they have undergone prior neurosurgical operations. Additionally, providers should recognize that these patients will require VPS systems that permit low pressure drainage. Improved recognition of LPH after TBI can advance understanding of underlying mechanisms and inform treatment strategies.
Lysophosphatidylcholine Drives Post-Recanalization “No-Reflow” via Pericyte Dysfunction in Ischemic Stroke
Mr. Christopher LeDoux1, Keren Powell1, Steven Wadolowski1, Ibrahim Rana1, Dr. Max Brenner1, Dr. Ping Wang1,
1The Feinstein Institutes for Medical Research, Manhasset, United States
Background: Despite successful recanalization, >50% of thrombectomy patients experience devastating outcomes due to microvascular “no-reflow” with zero approved therapies, affecting >400,000 U.S. patients annually. We discovered brain lysophosphatidylcholine LPC (18:1), a bioactive lysolipid, paradoxically accumulates post-stroke and correlates most strongly with penumbra-to-infarct conversion. We hypothesized LPC (18:1) causally drives pericyte-mediated “no-reflow.”
Methods: Adult rats underwent 2h tMCAO with intravenous LPC (18:1) or subcutaneous Varespladib (sPLA2 inhibitor blocking LPC (18:1) generation) supplementation at reperfusion. At 6h post-MCAO, we quantified cerebral perfusion (laser speckle flowmetry), capillary constriction/fragmentation, pericyte coverage/contraction, infarct volumes, and sensorimotor deficits. Human brain pericytes underwent oxygen-glucose deprivation with LPC (18:1).
Results: LPC (18:1) catastrophically reduced cerebral perfusion to 41% (vs. 56% vehicle), while Varespladib preserved 73%, proving LPC (18:1) causally drives microvascular failure. At 24h, LPC (18:1) doubled ischemic core (15.2% vs. 7.1%), accelerating penumbral conversion to infarct, while Varespladib reduced total lesion volume 30% (12.6% vs. 18.1%). Mechanistically, LPC (18:1) triggered three catastrophic failures: maximal endothelin-1 constriction (100% capillary coverage vs. 75%), severe vascular fragmentation (62% vessel length reduction vs. 40%), and pericyte depletion with extreme contraction. Varespladib completely prevented all pathologies, preserving normal microvascular architecture. In human pericytes, LPC (18:1) dose-dependently increased irreversible contraction/cell death from 25% to 53%.
Conclusions: This proves brain-generated LPC (18:1) causally drives pericyte-mediated microvascular “no-reflow.” LPC (18:1) induces pericyte contraction and death, triggering catastrophic microvascular constriction/fragmentation that prevent tissue perfusion despite successful recanalization. Varespladib's rescue by blocking LPC (18:1) generation, with proven safety in >4,500 patients, establishes LPC (18:1) inhibition as the first translatable adjunctive therapy addressing this devastating unmet need.
Acknowledgements: Supported by NINDS R21NS114763.
Machine Learning Classification of Brain and Spinal Cord Injury Using Actigraphy-Derived Sleep Signatures
1Department of Integrative Physiology, University of Colorado Boulder, Boulder, United States, 2Université de Montréal, Montreal, Canada
Sleep disturbance is a prevalent consequence of neurotrauma, including traumatic brain injury (TBI) and spinal cord injury (SCI), yet objective biomarkers distinguishing injury types remain lacking. While sleep disturbances may be common after severe orthopedic injury (SOI), distinct sleep phenotypes across central nervous system injuries versus peripheral trauma are poorly defined. No prior study has applied supervised machine learning to wrist actigraphy to classify neurotrauma injury type based on sleep profiles.
Continuous wrist actigraphy was collected from 61 inpatients (TBI n=33, SCI n=12, SOI n=15) across longitudinal windows. Night and day intervals yielded 24 sleep metrics per observation, including sleep efficiency, wake after sleep onset, fragmentation index, total sleep duration, and bout structure. Five composite features captured circadian and architectural dynamics (circadian disruption index, day/night consolidation, fragmentation severity, 24-hour disruption), producing a 31-feature input space. Seven supervised classifiers were evaluated for two clinically relevant tasks (TBI vs SOI; SCI vs TBI) using stratified five-fold cross-validation, area under the receiver operating characteristic curve (AUC), and average precision.
A stacking ensemble achieved the highest performance. Discrimination was strong for TBI vs SOI (AUC = 0.825 ± 0.033; AP = 0.896) and SCI vs TBI (AUC = 0.900 ± 0.054; AP = 0.975). Nighttime sleep efficiency emerged as the most informative feature.
These findings reveal injury-specific sleep signatures and demonstrate that actigraphy-derived sleep phenotyping can differentiate TBI and SCI using scalable, noninvasive monitoring. This approach advances precision neurotrauma care by providing objective physiological markers to guide clinical stratification and monitor potential recovery trajectories.
Machine Learning Factor Analysis Reveals Injury-Induced Multi-Compartment Inflammatory Heterogeneity and Its Therapeutic Attenuation After Controlled Cortical Impact
1University Of Pittsburgh, Pittsburgh, United States, 2VA Pittsburgh Healthcare System, Pittsburgh, United States
Traumatic brain injury (TBI) produces variable inflammatory responses, yet whether this heterogeneity extends across biological compartments and is therapeutically modifiable remains understudied. We applied machine learning to characterize multi-compartment inflammatory variation across brain, cerebrospinal fluid (CSF), and serum after controlled cortical impact.
Forty-eight male Sprague-Dawley rats underwent controlled cortical impact (CCI; 4 m/s, 2.7 mm depth) or sham surgery and received celastrol, a triterpenoid anti-inflammatory compound, or vehicle (DMSO) via intraperitoneal injection immediately and 24 hours post-injury (n=12/group). Ipsilateral hippocampal lysate, CSF, and serum were collected at 48 hours; nine cytokines were quantified by multiplex electrochemiluminescence immunoassay. Multi-Compartment Factor Analysis (MCFA), an unsupervised Bayesian approach adapted from Multi-Omics Factor Analysis, decomposed cytokine covariance into latent inflammatory axes. Group separation was tested by permutational multivariate analysis of variance (PERMANOVA) and inter-animal heterogeneity by permutational analysis of multivariate dispersion (PERMDISP; 9,999 permutations).
MCFA identified three factors capturing 74.5% of total variance: a hippocampus-dominant axis (89.5% hippocampal variance), a CSF-dominant axis (59.0%), and a serum-dominated axis (74.9%). PERMANOVA confirmed group separation (pseudo-F=5.90, p<0.001); the hippocampal axis distinguished injury from sham (p=0.002) and the serum axis celastrol from vehicle (p<0.01). PERMDISP revealed CCI-vehicle animals exhibited twice the dispersion (mean centroid distance=2.66) versus shams (1.31); celastrol attenuated dispersion to sham-like levels (1.07; p=0.001). Serum loadings on the hippocampal factor identified a peripheral signature tracking central inflammation.
These findings demonstrate animal-specific multi-compartment inflammatory heterogeneity and its therapeutic attenuation, quantified via machine-learning factor analysis, as a novel preclinical screening endpoint.
Mechanisms and Barriers for Understanding Neural Abundant Protein Efflux Following Traumatic Brain Injury
1Mind Research Network, Albuquerque, United States, 2University of New Mexico School of Medicine, Albuquerque, United States, 3Medical College of Wisconsin, Milwaukee, United States, 4University of Groningen, University Medical Center Groningen, Groningen, Netherlands, 5Children’s Hospital of Philadelphia, Philadelphia, United States, 6U.S. Army Aeromedical Research Laboratory, Fort Rucker, United States, 7Boston Children’s Hospital, Boston, United States
Quantifying traumatic brain injury (TBI) based on peripheral fluid protein concentrations is increasingly recommended by expert consensus panels. However, critical knowledge gaps remain regarding underlying mechanisms (e.g., de novo protein synthesis, changes in barrier permeabilities and/or glymphatic clearance), especially for “milder” injuries. Multiple experiments (N=52 swine) used precise, biomechanical targeting of three “mild-to-moderate” TBI levels, pharmacological manipulation of blood-brain barrier permeability (mannitol bolus), and dense temporal sampling of hyper-acute and acute phases to characterize protein kinetics and underlying mechanisms. Similar to previous findings, a non-linear relationship existed for peak angular velocity measured at the device versus swine head, with biomechanical coupling increasing at lower exposures. Glial fibrillary acidic protein (GFAP) and neurofilament light (NfL) exhibited dose-dependent relationships with precisely quantified biomechanics that varied in terms of early (minutes to hours post-injury; GFAP) versus late (one-week post-injury; NfL) peak efflux. Mannitol administration replicated trauma-related kinetics of protein release during hyper-acute to acute phases, implicating blood-brain barrier breach as a primary mechanism for protein efflux into blood and potentially suggesting that efflux dynamics are partially mediated by molecular weight. Immunohistochemical evidence (Immunoglobulin G) exhibited similar dose-dependent evidence of blood-brain barrier breach, but spatial deposition patterns varied across TBI (increased in sulcal fundi/deep gray matter) versus mannitol (diffuse deposition) models. Findings collectively suggest that multiple, non-exclusive mechanisms mediate post-traumatic protein efflux, and that commercially available proteomics may dynamically quantify blood-brain barrier integrity. Dose-dependent accumulation of pathology deep within sulcal depths further confirms the biological relevance of gyrencephalic models of mild-to-moderate TBI.
Mechanistically Anchored Trajectories of neoGFAP™ as a Blood Biomarker for Adult Traumatic Brain Injury Monitoring: A Single-Site Cohort Pilot Study
Kevin Wang1,2, Guangzheng Cai1,2, Khadija Boukholda2, Firas Kobeissy2, Eman Elbayoum2, Devin Jackson3, Katie Tehas3, Anthony DeLizza3, Caroline Popper3, Spyriodula Tsetsou4, Claudia Robertson4,
1Foundation for Applied Molecular Evolution, Alachua, USA, 2Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, USA, 3Gryphon Bio, South San Francisco, USA, 4Neurology and Neurosurgery, Vascular Neurology and Neurocritical Care, Baylor College of Medicine, Ben Taub Hospital, Houston, USA, 5Owl Therapeutics, Cambridge, USA
Background: Blood biomarkers for traumatic brain injury (TBI) are largely optimized for acute triage rather than serial monitoring. Total glial fibrillary acidic protein (GFAP) is an established astrocytic marker, but interpretation may be complicated by heterogeneous circulating GFAP proteoforms and non–injury-related variability.
Objective: We compared total GFAP with neoGFAP™, a mechanistically anchored ∼38–40 kDa calpain-truncated GFAP species bearing a defined neo-N terminus, using a trajectory-oriented framework for longitudinal monitoring in adult severe TBI.
Methods: Archived serial serum samples from adults enrolled in a single-site severe TBI randomized clinical trial (enrollment within 6 h) were assayed for total GFAP and neoGFAP™. Clinically actionable post-injury windows were defined as Early (6–72 h), Late (96–240 h), and All (6–240 h). Outcomes included 6-month global functional outcome (GOSE 1–6 vs 7–8). Models were evaluated using 5-fold stratified cross-validation with pooled out-of-fold predictions.
Results: Among 94 patients, 88% had GOSE 1–6 at 6 months. For GOSE prediction, adding log-transformed Late neoGFAP™ to an age+emergency-department GCS model improved discrimination versus adding total GFAP. Both analytes declined over days 1–10, with persistent separation of low/medium/high trajectory risk groups.
Conclusions: In this adult severe TBI cohort, blood measurement of the calpain-truncated GFAP proteoform neoGFAP™ provided stronger longitudinal prediction of functional outcome than total GFAP. These data support prospective validation of neoGFAP™ as a monitoring biomarker for disease-course tracking and clinical decision support after severe TBI.
Metabolic Solution Compositions with Neuroprotective, Antiseizure, and Cardioprotective Properties: Prospects for Treatment of TBI and Its Long-Term Consequences
1Dept. of Neurology, University of Wisconsin, Madison, United States, 2Department of Pathology, Veterinary Diagnostic Laboratory, University of Wisconsin, Madison, United States, 3Wm. S. Middleton VA Hospital, Madison, United States
2DG (2-deoxy-D-glucose) has established antiseizure and antiepileptic actions in multiple rodent seizure models. Preliminary studies have revealed that repeated daily dosing of 2DG (250 mg/kg, 3-14 days) after controlled-cortical-impact (CCI) in Perforant Path Kindling-Susceptible (PPKS) rats reduces secondary damage progression, decreases development of post-traumatic generalized spike-wave seizures (GSWS), and favorably modifies fear conditioning abnormalities implicated in post-traumatic stress disorder (PTSD). As daily dosing of 2DG for 14 days also induces reversible cardiomyocyte vacuolation, we investigated if combining 2DG with alternative cardiac nutrient energy sources might abrogate the reversible cardiotoxicity. Daily intraperitoneal administration of solutions combining 2DG (250 mg/kg) and the ketone β-hydroxy-butyrate (βHB) (936 mg/kg) immediately after CCI through day 14 in Sprague-Dawley (SD) rats reduced lesion volume by ∼50% compared to matched saline controls (lesion volume = 16 ± 3.4 vs. 34 ± 5.0 mm3, respectively, p = 0.0217). Metabolic solution compositions combining 2DG (2.5-10mM)+βHB (10-25mM) unexpectedly demonstrated enhanced antiseizure actions against spontaneous epileptic burst charges in CA3 exposed to 7.5 mM [K+]o (75% burst rate reduction vs. 47% with 2DG alone or 59% with βHB alone, p=0.046). Cardiomyocyte vacuolation in SD rats treated daily for 14 days with 2DG (250-535 mg/kg) +βHB(668-936 mg/kg) was reduced vs. 2DG alone (250-535 mg/kg) (vacuolation scores = 2.2 ± 0.17 vs. 3.043 ± 0.24, respectively) (p=0.039). Metabolic solutions combining 2DG with alternative cardiac nutrients such as β-hydroxybutyrate have neuroprotective, antiseizure, and cardioprotective actions, suggesting potential for treatment of TBI and its sequelae while avoiding adverse cardiac consequences.
Method-Driven Variance in Gait Coordination and Accuracy Measurements 24 Hours After Mild Traumatic Brain Injury in Mice
1Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, United States, 2Preclinical Behavior and Modeling Core, Department of Laboratory Animal Resources, Uniformed Services University, Bethesda, USA, 3Department of Anatomy, Physiology, and Genetics, Uniformed Services University, Bethesda, USA
Gait analysis is widely used to detect motor dysfunction following traumatic brain injury (TBI), yet many coordination metrics depend strongly on the locomotor platform used for assessment. Ambulation speed confounds most gait parameters: treadmill systems (e.g., DigiGait) constrain speed, whereas voluntary overground systems (e.g., MouseWalker) allow animals to dynamically adjust speed and gait strategy. To examine how platform and speed influence these metrics, acute gait parameters were compared in adult male mice that received either a single CHIMERA (Closed-Head Impact Model of Engineered Rotational Acceleration) brain injury (6.0 J; n=10) or sham procedures (n=10). Animals were tested one day post-injury on both DigiGait, a fixed-speed treadmill (14 cm/s), and MouseWalker, a voluntary overground locomotion system (∼24 cm/s). Measures included interlimb coordination, deviation from expected phase targets, and limb support distributions. During voluntary locomotion on MouseWalker, animals showed tighter phase clustering and predominantly used 2-limb (diagonal) support, consistent with dynamically modulated overground gait. In contrast, DigiGait trials showed larger deviations from expected phase targets and substantially greater 3-limb support, reflecting a more conservative support strategy under constrained conditions. Although speed significantly influenced several gait measures on MouseWalker, distinct platform effects persisted even after accounting for speed. Consequently, voluntary speed variation may reveal gait adaptations within a dynamic locomotor environment that are less apparent when locomotion is externally constrained. At this acute time point, platform-driven effects were larger than injury-related differences. These findings highlight the importance of locomotor context, task constraints, and speed when interpreting gait outcomes following experimental TBI.
Microbiome Driven Gut–brain Axis Dysfunction and Enteric Nervous System Remodeling in Chronic Abdominal Pain After Spinal Cord Injury
1University Of Kansas Medical Center, Kansas City, Kansas, United States
Neurogenic bowel (NB), characterized by slow colonic transit, fecal incontinence, and chronic abdominal pain, is common after central nervous system injuries, including spinal cord injury (SCI). Current therapies are focused on symptom management due to the knowledge gap surrounding underlying mechanisms. We recently identified a possible role for increased DRG, vagal and enteric neuronal responding to stimulation with fecal supernatant from SCI mice, suggesting dysbiosis may contribute to sensory dysfunction in NB. Further, we have found that fecal material transfer (FMT) from chronic SCI mice to naïve mice induces visceral hypersensitivity and metagenomic analysis of fecal material confirmed persistent microbial dysbiosis in chronic SCI (D28 post-injury), including overgrowth of the potentially pathogenic bacterium A. Anaeroplasma. Together, these findings point to a role for SCI-dysbiosis in increased pain transmission from the colon after SCI. Single-nucleus RNA sequencing of enteric neurons from naïve and chronic SCI mice revealed a decrease in putative interneurons and an increase in a population of Nos1+ putative inhibitory motor neurons previously shown to have mechanosensory capacity after SCI. Moreover, expression of the microbial endotoxin receptor Tlr4 is largely restricted to a population of likely intrinsic sensory afferents showing modest expansion in chronic SCI. Collectively, these findings point to SCI-induced microbial imbalance and subsequent alterations in extrinsic and intrinsic neuron responses and ENS remodeling may underlie gut-brain axis dysregulation after SCI. Understanding the potential role of the microbiome in post-SCI bowel pain and dysfunction is critical to the development of mechanism-focused therapeutic strategies for NB.
Microbiome-Derived Metabolites as Modulators of Ion Channel Dysfunction in Traumatic Brain Injury
1Department of Emergency Medicine, Burlington, USA, 2Department of Pharmacology, Burlington, USA, 3Department of Surgery, Burlington, USA, 4The Robert Larner MD College of Medicine, Burlington, USA, 5The University of Vermont Cancer Center, Burlington, USA
Traumatic brain injury (TBI) is a leading cause of mortality and long-term disability worldwide, and effective therapeutic interventions remain limited. Ion channels are key regulators of cellular excitability and homeostasis in the mammalian brain, and their dysfunction following TBI has been associated with worsened neurological outcomes and reduced survival. We previously showed that metabolites, including microbiome-derived short-chain fatty acids (SCFAs), can mitigate lesion size, neurodegeneration, and functional deficits after TBI. However, the effects of these metabolites on brain ion channels following injury remain poorly understood.
We hypothesized that TBI alters the metabolite landscape in the brain and that specific metabolites, including SCFAs, may rescue TBI-induced dysfunction of ion channels such as inward-rectifier potassium channels.
To test whether gut metabolites are depleted in TBI, we employed single and triple blast TBI models, performing metabolomic profiling to identify metabolites differentially regulated following injury.
Our analysis identified over 30 differentially regulated metabolites after TBI, including propanoyl-carnitine, L-carnitine, and urate (p = 0.023, 0.034, and 0.017; t-test, TBI/Sham, respectively), suggesting significant metabolic alterations associated with injury severity.
We conclude that TBI induces substantial metabolic remodeling that may influence ion channel function in the injured brain. Ongoing electrophysiological studies are investigating whether gut-derived metabolites such as SCFAs can restore impaired activity of inward-rectifier potassium channels and elucidating the cellular and molecular mechanisms underlying these effects to identify novel therapeutic targets for TBI.
Microglia Cluster into Multicellular Nodules in White Matter Tracts Following a Closed-Head Diffuse Traumatic Brain Injury in Pigs
1Center for Brain Injury & Repair, Department of Neurosurgery, University of Pennsylvania, Philadelphia, United States, 2Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, United States, 3Neuroscience Graduate Group, Biomedical Graduate Studies, University of Pennsylvania, Philadelphia, United States
Traumatic brain injury (TBI) affects 2.5 million people in the U.S. each year and results in disrupted neuronal circuitry, lasting neurological deficits, accelerated brain aging, and increased risk for neurodegeneration. Microglia are rapid and chronic responders to TBI, undergoing morphological, phenotypic, and functional changes that influence recovery and degeneration. Human postmortem studies show that weeks after injury, microglia form multicellular nodules that persist for years, and these nodules precede and spatially associate with neurodegenerative proteinopathies.
Here, we characterized white matter microglia after a closed-head diffuse TBI in pigs. Animals experienced either sham or rotational TBI (99.4 ± 1.3 radians per second sagittal rotation) and survived 3-, 7-, or 14-dpi, with sham animals surviving 3 days. In fixed tissue stained for Iba1, white matter microglia showed striking morphological changes, with 3 to 20 cells clustering into multicellular nodules. These nodules retained expression of the microglia signature gene Sall1, were most prominent at 14-dpi, and were abundant in the corpus callosum and subcortical white matter. Although data collection is ongoing, nodules tended to contain myelin debris and were not directly associated with axonal pathology (APP). Single nuclear RNA sequencing of white matter will compare microglial gene expression in injured and sham brains and assess how transcriptional profiles change over time.
These findings indicate that white matter microglia undergo persistent morphological alterations into the sub-acute phase after diffuse TBI. Ongoing work will determine how multicellular microglia nodules enhance tissue repair or contribute to degeneration.
Microglia Turnover Modulates Behavioral Outcomes After Early Life Stress and Pediatric Traumatic Brain Injury in Rats
Dr. Marissa Smail, Yoon-Jae Yi, Miranda McDonald, Kristin Lee, Olivia Wirfel, Rebecca Boland, Xander Weinstein, Jake Roush, Alejandra Zaleta Lastra, Dr. Cole Vonder Haar, Dr. Jonathan Godbout, Dr. Olga Kokiko-Cochran,
1The Ohio State University, Columbus, United States
Pediatric traumatic brain injury (TBI) impacts >500K children annually, leaving >20% with lasting symptoms. Early life stress (ELS) and sex can influence these outcomes. We used a rat model of ELS and pediatric TBI, which generates behaviors that reflect human symptomology. In this model, microglia exhibit heightened responses to stress and injury during neurodevelopment. Here, we experimentally tested a causative role for microglia in programming the behavioral effects of ELS and pediatric TBI in male and female rats. Studies used a 2(ELS)x2(TBI)x2(Drug)x2(SEX) design (n=8-12). ELS consisted of maternal separation for 4 hours/day from postnatal day (P)1-14. TBI consisted of a mild lateral fluid percussion injury on P15. BLZ945 (CSF1R inhibitor) was administered on P11-12 to force turnover at end of ELS and prior to TBI to test if microglia renewal mitigated ELS effects on behavioral outcomes. From P45-P60, rats underwent behavioral testing, including novel object recognition, Y maze, social interaction, and forced swim. Data were analyzed using mixed effects linear models. Microglia turnover impacted multiple ELS, TBI, and SEX effects and interactions. BLZ partly rescued novel object recognition deficits in ELS, TBI and ELS+TBI males. BLZ blocked TBI-related increases in spontaneous alternation in control-reared animals but enhanced these effects in ELS animals. BLZ normalized immobility during forced swim, reversing both ELS-related increases in passive coping in both sexes and TBI-related increases in active coping in females alone. Overall, microglia contribute to ELS and pediatric TBI behavioral outcomes, offering insight into the therapeutic potential of microglia following early life insults.
Microstructure of cortical gray matter is altered in relation to soccer heading: novel application of magnetic resonance elastography
Teah Serani1, Alma Davidson1, Ariana Olivares1, Adriana Dipple1, Orion Valentine1, Finn Myrick1, Dr. Roman Fleysher1, Dr. Grace McIlvain1,
1Columbia University, New York, United States
Objectives: Soccer repetitive head impacts (RHI) are associated with white matter (WM) microstructural changes that mediate cognitive dysfunction. Brain surface to skull impact occurs with RHI and cortical gray matter (GM) is a site of pathology in CTE. However, RHI effects on GM have not been demonstrated. We applied magnetic resonance elastography (MRE), an emerging MRI technique, to assess tissue mechanical properties that reflect GM microstructural integrity in relation to RHI.
Methods: We estimated prior 12-month RHI and performed 3 Tesla MRE and T1-weighted MRI scans in 39 amateur soccer players, 26 non-collision athletes, and 25 non-athlete controls. A nonlinear inversion algorithm estimated stiffness(µ) and damping ratio(ξ). Regions of interest were generated using FreeSurfer. Age- and sex-regressed ANOVA with Tukey post hoc testing assessed group differences. The association of heading with GM mechanical properties was tested in soccer players using Spearman correlation.
Results: Global brain µ differed significantly between groups (p<0.001), with soccer players exhibiting higher µ (mean±SD = 2.92±0.18 kPa) than non-contact athletes (2.80±0.19 kPa) and controls (2.78±0.15 kPa). Differences were greater in cortical GM (soccer: 2.65±0.23 kPa; athletes: 2.51±0.21 kPa; p<0.001; controls: 2.48±0.25 kPa) than cerebral WM (p= 0.06). Cortical ξ was significantly (p= 0.0015) lower in soccer players (0.24± 0.01; athlete: 0.25±0.01; control 0.25± 0.02) and greater RHI was associated with lower ξ (p=0.003).
Conclusion: Soccer players, particularly those with higher RHI, exhibit altered brain mechanical properties compared to noncollision athletes and controls. Findings are consistent with neuroinflammation, including microglial activation, astrocytic hypertrophy, and extracellular matrix remodeling.
Microtransport-Related Traumatic Brain Injury in New York City: Injury Patterns and Admission Predictors
1SUNY Downstate College of Medicine, Brooklyn, United States, 2Department of Neurosurgery, Mount Sinai Health System, New York, United States
Objective: Microtransport vehicles are increasingly common in urban environments, yet patterns of traumatic brain injury (TBI) associated with their use remain poorly characterized. This study evaluated demographic, socioeconomic, and injury characteristics of microtransport-related TBI and predictors of admission.
Methods: We conducted a retrospective cohort study of adults (≥18 years) presenting to the emergency department with TBI following pedal bicycle, electric-powered, or motorized microtransport crashes at a Level II trauma center in New York City from January 2023 to June 2024. Demographic, socioeconomic, helmet use, and injury variables were compared across groups. Univariable and multivariable logistic regression identified predictors of inpatient admission.
Results: Among 112 patients, 43.8% were electric riders, 23.2% motorized riders, and 33.0% pedal riders. The cohort was predominantly male (85.7%), and pedal riders were older (median 52 years). Electric and motorized riders were more frequently Hispanic (p = 0.028). Helmet use was uncommon (64.8% no helmet), particularly among electric riders (78.7%). Motorized riders had the highest rates of serious head injury (Abbreviated Injury Scale ≥3: 46.2%, p = 0.026), polytrauma (Injury Severity Score ≥15: 30.8%, p = 0.022), and ICU admission (34.6%, p = 0.026). On multivariable analysis, only serious head injury predicted inpatient admission (adjusted odds ratio 15.1, 95% confidence interval 3.4-107.2, p = 0.001).
Conclusions: In this urban cohort, microtransport-related TBI was marked by low helmet use, socioeconomic disparities, and greater injury severity among motorized riders. Admission was driven by head injury severity rather than transport type, supporting severity-based triage and targeted prevention strategies.
Mid-life Social Relationships, TBI, and Dementia Risk
1Department of Neurology, University Of Pennsylvania Perelman School Of Medicine, Philadelphia, United States, 2Injury Outcomes Network, Englewood, United States, 3Optimal Aging Institute, New York University, New York, United States, 4Intramural Research Program, National Institute of Neurological Disorders and Stroke, Bethesda, United States, 5Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States
Objective: Traumatic brain injury (TBI) is a risk factor for dementia. Psychosocial modifiers, such as weak social relationships and social isolation, are also associated with increased dementia risk as well as worse outcomes after TBI. We examined whether mid-life social relationships modify the association between TBI and dementia risk.
Methods: Participants in the Atherosclerosis Risk in Communities (ARIC) study completed assessments of social support and social isolation in 1990–1992, which were combined into a composite ‘social relationships’ measure (strong versus poor social relationships). We used Cox proportional hazards models to estimate associations between time-varying TBI and incident dementia from 1990–1992 to date of dementia, death, study withdrawal/loss-to follow-up, or administrative censoring on 12/31/2022. We assessed interaction by mid-life social relationships strength on multiplicative and additive scales. Models were adjusted for demographic and clinical/behavioral characteristics.
Results: Among 11,681 participants (58% female; mean baseline age 57 years; 57% “strong” social relationships) without baseline TBI or dementia, 1,218 developed TBI and 2,883 developed dementia over a median of 23.6 years follow-up. In adjusted models, TBI was associated with an increased risk of dementia (HR=1.57, 95%CI=1.42-1.75). Strength of social relationships did not meaningfully modify the association between TBI and dementia risk (strong relationships: HR=1.61, 95% CI=1.40-1.84; poor relationships: HR=1.54, 95% CI=1.31–1.82).
Conclusion: TBI was associated with increased dementia risk, but this risk did not differ by mid-life social relationship strength. Future work should consider the role of social relationships in later life and target additional modifiable risk factors for dementia.
Mitochondrial Hyperpolarization Causes OMA1 Dependent Network Fragmentation After Neuron Stretch Injury
1University of Michigan, Ann Arbor, United States, 2Department of Emergency Medicine, Ann Arbor, United States, 3Neuroscience Graduate Program, Ann Arbor, United States
Traumatic Brain Injury (TBI) arises from a wide variety of injury mechanisms that can lead to long-term disability. The immediate mechanical damage defines the primary injury, whereas reactive molecular processes emerge over time and are considered secondary injury. During this cascade, mitochondrial damage leads to increased energetic demands, ROS production and neuronal death. In order to maintain mitochondrial homeostasis, the electron transport chain proton gradient generates mitochondrial membrane potential (MMP) across the inner mitochondria membrane (IMM). Mitochondrial maintenance mechanisms regulate quality control pathways for morphology, division and turnover. The IMM contains compartmentalized proteins, including OMA1, a stress induced protease that plays a role promoting mitochondrial fragmentation and removal of damaged mitochondrial components. Emerging evidence suggests that hyperpolarization of MMP contributes to mitochondrial dysfunction and ROS production in neurological injuries, however its role in TBI is unexplored. We hypothesize that MMP hyperpolarization contributes to mitochondrial fragmentation through ROS-induced activation of OMA1 leading to cellular injury. We explored the role of elevated MMP by chemically inducing hyperpolarization with oligomycin in live-cell imaging of MMP (TMRE) and mitochondrial superoxide (MitoSOX green) in HT22 neurons. Using our novel structural classifier, we analyzed and characterized changes in mitochondrial morphology of unhealthy mitochondria. Additionally, we investigated the change in MMP regulation after the neuronal stretch injury model of TBI. Analysis of MMP and mitochondrial morphology in OMA1 KO cells provide an understanding of how OMA1 contributes to mitochondrial dysfunction and injury progression.
Modeling Blast Traumatic Brain Injury Using a Bioengineered 3D Neural Tissue Platform
1HJF - Uniformed Services University, Silver Spring, United States, 2Preclinical Behavior and Modeling Core, Uniformed Services University, SILVER SPRING, United States, 3Department of Biomedical Engineering, University of Cincinnati, Cincinnati, United States
Since 2000, over 530,000 U.S. service members have suffered a traumatic brain injury, with a majority caused by blast exposure. Despite its prevalence, blast-related TBI (bTBI), particularly mild bTBI, lacks clear clinical indicators and remains difficult to diagnose. The molecular mechanisms underlying primary bTBI are poorly understood, underscoring the need for models that enable controlled investigation of blast injury mechanisms and damage markers. To address this gap, we utilized a bioengineered three-dimensional (3D) human brain-like culture system to model blast-induced injury. The platform uses hybrid collagen-infused silk scaffold hydrogels seeded with human iPSC–derived neural stem cells, astrocytes, and microglia, partially recreating the brain's cellular microenvironment. Over weeks, constructs form interconnected neural networks with axonal projections spanning the scaffold architecture. Blast exposure is delivered via a controlled advanced blast simulator, with tissues housed in a custom 3D-printed surrogate chamber that preserves sterility and structural integrity during the blast. Post-exposure, engineered tissues were evaluated for injury and neuroinflammatory markers using colorimetric assays, immunostaining, and immunoblotting. Blast-exposed cultures exhibited increased lactate dehydrogenase activity and glutamate release at 24 and 72 hrs post injury, indicative of membrane disruption and excitotoxic stress. Immunostaining with antisera against βIII tubulin and amyloid precursor protein, revealed increased axonal varicosities consistent with impaired axonal transport. Elevated expression of injury markers at acute time points confirmed robust cellular injury and neuroinflammation. Metabolic markers were also altered by blast exposure. Overall, this 3D platform provides a controlled, scalable, human-relevant model for careful dissection of the mechanisms underlying bTBI.
Modeling Central Nervous System Polytrauma: Development of a Rodent Model of Concomitant Mild Traumatic Brain Injury and Spinal Cord Injury
1Medical College of WI, Milwuakee, United States, 2Clement J. Zablocki VA Medical, Milwuakee, United States
Polytrauma involving both the brain and spinal cord is common after traumatic injury, yet the biological consequences of combined central nervous system (CNS) damage remain poorly understood. Spinal cord injury (SCI) is a life-altering condition that causes persistent motor, sensory, autonomic, and respiratory deficits Following the initial mechanical insult, SCI progresses through a secondary phase characterized by hemorrhage, inflammation, and progressive tissue degeneration that exacerbates neurological dysfunction. Notably, an estimated 60% of SCI patients sustain a concurrent mild traumatic brain injury (mTBI). Although often classified as mild, mTBI can produce lasting cognitive and behavioral impairments. Despite the prevalence of concurrent SCI and mTBI, mechanistic understanding of combined CNS trauma is limited. Clinical studies suggest worsened functional outcomes but lack experimental control. The few preclinical models of combined CNS injury use severe TBI models which do not fully reflect the typically observed mild TBIs.
To address this gap, we are developing a clinically relevant rodent model of concomitant mTBI and SCI. Mice undergo closed-head impact mTBI immediately followed by thoracic SCI. Pilot studies focused on optimizing injury parameters to produce a reproducible and behaviorally distinct phenotype and suggest a mild but detectable functional impairment, reflective of mTBI. Elevated Plus Maze and Morris Water Maze testing were used to assess anxiety-like behavior and spatial memory deficits associated with mTBI, and immunofluorescence analyses characterized injury severity and tissue pathology. Establishing this model will enable mechanistic investigation of CNS polytrauma and support development of targeted therapeutic strategies for this understudied patient population.
Modeling CTE-Associated Pathological Features: A Human 3D In Vitro Triculture System for Mild Repetitive Injury
1Department of Biomedical Engineering, University of Cincinnati, Cincinnati, United States, 2Neuroscience Graduate Program, College of Medicine, University of Cincinnati, Cincinnati, United States, 3Pharmacology & Molecular Therapeutics, School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, United States
Chronic traumatic encephalopathy (CTE) is a progressive neurodegenerative disease linked to mild repetitive head trauma. Currently, CTE is definitively diagnosed postmortem via pTAU aggregates, making it impossible to study early disease onset in living patients. Consequently, no diagnostic criteria or targeted treatments exist for individuals with mild traumatic brain injury (TBI) who may develop CTE. Developing a system to investigate molecular mechanisms and biomarkers across the CTE timeline is therefore urgently needed.
Human iNSC-neurons, primary astrocytes, and microglia were embedded in 3D silk-collagen scaffolds (2:0.5:0.1 ratio). Injury was inflicted using a controlled cortical impactor (CCI) to optimize tip size, speed, and time intervals. Our study revealed that calibrated mild impacts (1mm at 1 m/s) maintained neuronal network integrity, enabling robust repetitive injury modeling.
Applying three repetitive TBIs with a 14-day interval induced a sustained increase of pTAU (AT8, THR231, PHF1) and TDP-43 up to four weeks, confirmed by Western blot, multiplex analysis, and immunofluorescence. Crucially, these injuries triggered significant mitochondrial dysfunction and metabolic shifts. We observed an acute compensatory rise in glycolysis (ECAR) during the first week, followed by a significant glycolytic depression at four weeks. Oxygen consumption (OCR) dropped immediately post-injury, transiently increased by 72 hours, and stabilized by one week.
This 3D human model reliably reproduces early CTE-like signatures, demonstrating that a loss of metabolic compensation coincides with sustained proteinopathy. These results position mitochondrial dysfunction as an early driver of CTE pathology, guiding future studies on metabolic contributors to long-term neurodegeneration.
Moderating Effect of the Mediterranean Diet on Traumatic Brain Injury and Depression: A National Health and Nutrition Examination Survey Study
1University Of Pittsburgh, Pittsburgh, United States
Objectives: Traumatic brain injury (TBI) increases risk for depression. Systemic inflammation can increase depressive symptoms. The Mediterranean Diet (MD) has an anti-inflammatory effect and can improve depression; it is unknown if the MD can attenuate depression symptoms after TBI exposure.
Methods: Data were downloaded from the National Health and Nutrition Examination Survey (NHANES) study website for the 2011-2012 and 2013-2014 cycles. Diet was reported to a interviewer for the 24-hour period immediately preceding. The Alternate Mediterranean Diet (aMED) index was calculated, which ranges from 0 (low adherence) to 9 (high adherence). A general linear model predicted Patient Health Questionnaire 9 (PHQ9) total scores using TBI history, high adherence to MD (vs. moderate/low adherence) and their interaction. Age, gender, race/ethnicity, education and poverty-income ratio were covariates. To test whether systemic inflammation modified outcomes, a series of general linear models were built with the same predictor/covariate set and several serum inflammatory indices.
Results: A main effect was observed for TBI (β=0.31; p=0.001), age (β=-0.01; p=0.001), gender (β=0.21; p<0.001) and poverty-income ratio (β=-0.14; p<0.001). The interaction of TBI and high adherence to the MD (β=-0.37; p=0.03) was significant. After including the inflammatory indices in separate models, the interaction between TBI and high adherence to the MD remained (p=0.023-0.030).
Discussion: In this nationally representative sample of U.S. civilians, high adherence to the MD neutralized the negative impact of TBI exposure and current depression symptoms. This effect was not impacted by systemic inflammation, suggesting that the underlying mechanism may be central rather than peripheral.
Multiomic miRNA–Proteomic Profiling Identifies Biomarkers of Neurological Outcome After Traumatic Brain Injury
1Johns Hopkins University School of Nursing, Baltimore, United States, 2Uniformed Services University of the Health Sciences, Bethesda, United States, 3University of Chicago, Chicago, United States, 4Orlando Regional Medical Center, Department of Emergency Medicine, Orlando, United States, 5Johns Hopkins University School of Medicine, Neurology, Baltimore, United States
Introduction: Traumatic brain injury (TBI) triggers complex secondary injury cascades, yet tools for early mechanistic stratification and prognostication remain limited. Circulating microRNAs (miRNAs) are compelling biomarkers due to their stability, brain-enriched origins, and regulatory roles in inflammation and neuronal stress. We evaluated candidate miRNAs for associations with neurological outcomes in adults with TBI.
Methods: We profiled 168 acute plasma samples from a multicenter trial of moderate-to-severe TBI and performed integrated multiomic validation. Participants were classified into control vs. negative outcome groups. Using the NanoString nCounter miRNA Expression Assay, we identified five miRNAs significantly dysregulated in patients with negative neurological outcomes. We applied Olink proximity extension assay (PEA) proteomics to confirm predicted miRNA target proteins.
Findings: miR-144-3p, miR-3158-3p, and miR-378i were upregulated, while miR-212-3p and miR-1283 were downregulated in patients with negative outcomes. Proteomics profiling confirmed that predicted miRNA target proteins (including JUN, MMP9, SUFU, and CCND2) exhibited directionally consistent expression changes. miR-144-3p associated with upregulation of JUN signaling, and miR-212-3p corresponded with higher MMP9 expression, implicating neuroinflammation, blood-brain barrier breakdown, and neuronal death pathways. Canonical pathway analysis further implicated ERK/MAPK and WNT/β-catenin and senescence/stress-response networks in outcome discrimination.
Implications: Acute dysregulation of circulating miRNAs, supported by proteomic target networks, reflects biologically coherent pathways associated with neurological outcomes after TBI and may contribute to outcome variability. This dual-platform molecular profiling approach identifies miR-144-3p, miR-3158-3p, miR-378i, miR-212-3p, and miR-1283 as candidate prognostic biomarkers and potential targets for mechanistic risk stratification in neurotrauma. Prospective validation could enable molecularly informed decision-making in neurotrauma care.
Multi-Omics Identify Unique Protein Signature of Repeated Traumatic Brain Injury in Plasma and Cerebrospinal Fluid
1Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, United States, 2Department of Surgery, University of Pittsburgh, Pittsburgh, United States, 3Vanderbilt University, Nashville, United States
Traumatic brain injury (TBI) is a heterogeneous condition and involves multiple pathophysiological pathways that compound over time. High-dimensional protein and metabolic assays are well-suited for identifying biological processes given the broad range of injury and recovery mechanisms. We hypothesized that a multi-omic approach would distinguish a cohort of repeated (r)TBI participants from controls, as well as from a cohort of severe (s)TBI patients [initial Glasgow Coma Scale score 3-8, positive control]. Under IRB approved protocols, participants with a history of rTBI and self-reported cognitive complaints (n=22), cognitively intact controls (n=8) and sTBI patients (n=9) had plasma and cerebrospinal fluid (CSF) from a single time-point analyzed using proteomics (Alamar, Seer) and metabolomics (Metabolon). In plasma, K-means clustering of proteins identified a module enriched with neural (BDNF, APOE, NPTX1) and immune (IL6R, CCL17) markers, which were relatively higher in rTBI compared to controls. In CSF, principal component analysis separated all three groups by proteome. sPLS-DA predicted rTBI versus control (AUC=0.896). Gene set enrichment analysis showed reduced enrichment of synaptic and axonal pathways in rTBI versus control (adjusted p<0.05). No differences in plasma and CSF metabolites were observed between rTBI and controls, although many pathways were significantly altered in sTBI. Additional analysis is underway to associate protein changes with specific cognitive outcomes and neuroimaging. Altogether, these data identify unique protein signatures of rTBI in both plasma and CSF distinct from controls and sTBI. Targeted validation of key biomarkers may lead to improved diagnosis, monitoring and intervention strategies for individuals with rTBI.
Multi-scale High-Definition Fiber Tractography Reveals Persistent Corpus Callosum Network Disruptions in Pre-clinical and Clinical Mild TBI
1Department of Neurosurgery, University of Pittsburgh, Pittsburgh, United States, 2Department of Pediatrics, University of Pittsburgh, Pittsburgh, United States
Repeated mild traumatic brain injury (rmTBI) frequently results in persistent cognitive impairment despite often normal clinical imaging, suggesting that subtle disruptions in structural brain networks underlie long-term deficits. We hypothesized that the mechanism involves multi-scale disruptions in structural connectivity from local hippocampal circuits to global inter-hemispheric networks. We employed high-definition fiber tractography (HDFT) and graph theoretical connectomics to identify persistent disruptions and establish a translational framework for tracking longitudinal network changes in both preclinical studies and TBI patients. Male Sprague Dawley rats (8-10wks) received dual mild lateral fluid percussion injuries (1.25 atm) or sham surgeries 24hr apart (n=18/group). 8wks post-injury, rmTBI rats exhibited significant spatial learning deficits (ANOVA, p<0.05). Ex vivo HDFT (n=6/group) with graph theoretical analysis quantified connectivity across intra-hippocampal, inter-hippocampal, and whole brain scales. Contrary to our hypothesis, the intra-hippocampal trisynaptic circuit was preserved; however, significant connectivity disruptions at the inter-hippocampal and whole-brain levels were observed (Unpaired t-tests, p<0.05). Reduced corpus callosum volume was corroborated by histological evidence of demyelination and gliosis. This computational HDFT framework was translated to longitudinal in vivo imaging in TBI patients with repeat scans to assess within-subject structural connections 1-year post-TBI. Analysis revealed a dynamic remodeling characterized by a compensatory increase in corpus callosum fiber density within the right hemisphere. This asymmetry mirrored the preclinical model, suggesting a conserved biological signature of injury-induced network reorganization. These findings identify a shared connectomic profile between rmTBI and mTBI patients, demonstrating that longitudinal HDFT provides a robust translational framework for tracking chronic structural connectivity changes post-mTBI.
Multisensory 40 Hz Gamma Stimulation Modulates Glymphatic Transport Recovery Following TBI
1Georgia Institute of Technology, Atlanta, United States, 2Georgia Tech/Emory, Atlanta, United States
The glymphatic system facilitates cerebrospinal fluid (CSF) transport and waste clearance and is impaired following traumatic brain injury (TBI). We assessed whether noninvasive gamma stimulation can restore glymphatic function after TBI. Male Sprague Dawley rats (∼12 weeks old, 350-450 g; nsham= 4, nTBI=4, nTBI+Flicker=4) received 3 closed head impacts (5 m/s; head displacements = 5, 2, 2 mm) delivered at 2-minute intervals. Injury was confirmed by delayed righting latency and increased neurological severity score. At 24 hours post-TBI, animals underwent a single 1-hour session of audiovisual 40 Hz stimulation (flicker). One hour after stimulation, tracer (AF488-dextran, 3 kDa, 7µl) was injected into the cisterna magna. After 1 hour, brain tissue was sectioned coronally (+3.4, 0, -1.8, -3.3, -5.6 mm from bregma), and total fluorescent intensity (TFI) was measured (ImageJ). TFI was significantly decreased across all brain sections in TBI vs. sham animals (p < 0.0001); however, at bregma +3.4 and 0 mm, TBI + Flicker animals showed significantly increased TFI vs. TBI-only animals (p < 0.05). These results suggest that 40 Hz flicker stimulation may partially restore glymphatic transport to the frontal brain after TBI. Notably, changes were observed after only a single 1-hour session, indicating a rapid effect; additional sessions may be required to produce larger or sustained changes. Cervical lymph node analysis is ongoing to assess whether flicker affects peripheral drainage. Flicker stimulation promotes cortical neuronal entrainment, which may positively influence neurovascular and neuroimmune processes and is a potential therapeutic avenue for TBI.
Neural Stem Cell Extracellular Vesicle Therapy Improves Cellular and Functional Recovery in a Pediatric Traumatic Brain Injury Porcine Model
1Regenerative Bioscience Center, University of Georgia, Athens, United States, 2Department of Animal and Dairy Science, University of Georgia, Athens, United States, 3Department of Pathology, University of Georgia, Athens, United States, 4Aruna Bio, Athens, United States
Traumatic brain injury (TBI) affects over 2.8 million individuals annually in the United States and remains a leading cause of death and long-term disability, particularly in children. Pediatric TBI disrupts critical neurodevelopmental processes and often leads to chronic neuropathological changes, resulting in persistent functional deficits. Despite its prevalence, no FDA-approved therapies currently exist for TBI. Neural stem cell-derived extracellular vesicles (NSC EVs) have demonstrated cellular and functional efficacy in preclinical rodent models. However, they have yet to be tested in a translational large-animal pediatric TBI model predictive of human outcomes. We hypothesized that NSC EV treatment would preserve neural populations, attenuate neuroinflammation, and enhance neurogenesis, leading to improved motor function in a pediatric TBI porcine model. Thirty piglets underwent controlled cortical impact targeting the left motor cortex and were randomized to receive vehicle, low-dose (3 × 1010particles/kg), or high-dose (3 × 1011particles/kg) NSC EVs (n=10/group) administered intravenously at 6, 24, and 48 hours post-injury. Gait was assessed longitudinally through 91 days post-injury, after which brains were collected for histological analysis. NSC EV treatment preserved cortical thickness (p≤0.01), increased neuron (NeuN+; p≤0.0001) and oligodendrocyte (Olig2+; p≤0.0001) survival, and promoted neurogenesis (DCX+; p≤0.0001), while reducing glial scaring (GFAP+; p≤0.0001) and microglial (Iba1+; p≤0.0001) activation. Functionally, NSC EV-treated animals exhibited reduced gait cycle (p≤0.05) and stance (p≤0.05) times, indicating improved motor coordination. These findings demonstrate that NSC EV therapy mitigates neuropathological changes and promotes functional recovery in a clinically relevant large-animal pediatric TBI model, supporting its potential as a minimally invasive, cell-free therapeutic.
Neurobehavioral and Electrophysiological Markers of Cognitive Control During Neuromodulation After Traumatic Brain Injury: Interim Results From the SMART Study
1University of Minnesota, Minneapolis, United States, 2Hennepin Healthcare Research Institute, Minneapolis, United States
Background: Traumatic brain injury (TBI) is associated with persistent impairments in cognitive control, motivation, and value-based decision-making. Neuromodulation may improve these deficits, but sensitive behavioral and electrophysiological markers of treatment response remain poorly defined.
Objective: To characterize interim behavioral and electrophysiological markers of cognitive control and task engagement during an ongoing longitudinal neuromodulation study in TBI.
Methods: Participants with TBI and healthy controls completed repeated effort-based decision-making (COGED), reinforcement learning (bandit), and n-back EEG assessments across visits with sham and active stimulation conditions. Behavioral metrics including subjective value, response time, and reward sensitivity were analyzed longitudinally. EEG data underwent strict artifact rejection and recording-level quality control, and event-related potential (ERP) features were quantified with emphasis on canonical cognitive control components (P3 and N2).
Results: Interim analyses included 11 participants (9 TBI, 2 healthy). Behavioral results demonstrated consistent task engagement, including stable effort-value structure in COGED and reward-sensitive behavior in the bandit task. The most robust interim behavioral finding was longitudinal improvement in response time across visits. EEG analyses revealed interpretable task-related structure, including trial-type and load modulation of canonical ERP components (P3/N2). Stimulation-related contrasts were heterogeneous and not yet definitive at the current paired sample size.
Conclusions: These findings support the feasibility of combined behavioral and EEG markers for monitoring cognitive control in longitudinal neuromodulation studies after TBI. The SMART analysis pipeline provides a scalable framework for detecting treatment-related neurobehavioral changes as paired sham–active enrollment increases.
Neuroimmune Mechanisms of Male Infertility Following Spinal Cord Injury
1Department of Biology, Texas A&M University, College Station, United States, 2Department of Biochemistry, Texas A&M University, College Station, United States, 3School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, United States, 4Texas A&M Institute for Neuroscience, Texas A&M University, College Station, United States
Objective: Spinal cord injury (SCI) causes lifelong neurological impairments and systemic complications, including male infertility; however, underlying mechanisms remain poorly understood. Although reduced semen quality has been reported in most men with SCI, the contribution of disrupted autonomic and immune regulation in the testes is unclear. We hypothesized that SCI alters sympathetic input to the testes and promotes testicular immune cell infiltration, leading to impaired sperm quality and testicular pathology.
Methods: We used a thoracic T8 transection model in adult male rats. For reproductive outcome analysis, testicular histology was evaluated to assess seminiferous tubule architecture, and immunofluorescence was performed to assess immune cell infiltration within the seminiferous tubules. Representative sperm motility videos were collected to illustrate functional deficits. In a separate cohort, we employed a trans-synaptic tracing strategy using pseudorabies virus (PRV) to map sympathetic pathways from the spinal cord to the testes. Corresponding spinal cord segments (T10–L2) were cleared using an organic solvent–based tissue clearing method. Cleared spinal cord tissue was imaged and analyzed to assess injury-associated changes in the spinal cord-testis/epididymis circuit.
Results: SCI significantly reduced sperm motility and viability compared to sham controls. Histological analysis revealed disrupted seminiferous tubule architecture, including disorganization of the germinal epithelium. Immunofluorescence demonstrated increased immune cell infiltration within the seminiferous tubules following SCI, indicating loss of testicular immune privilege.
Conclusion: These findings demonstrate that SCI induces functional, structural, and immunological alterations in the male reproductive system, suggesting that neuroimmune dysregulation contributes to SCI-associated male infertility.
Funding: Craig H. Neilsen Foundation
Neuroimmune Modulation of Sleep After Traumatic Brain Injury: Effects of Microglial Depletion and Repopulation
1University of Colorado, Boulder, United States, 2University of Colorado, Denver, Denver, United States
Traumatic brain injury (TBI), particularly when preceded by poor sleep, produces persistent alterations in sleep-wake regulation that worsen neurological and behavioral outcomes. We hypothesized that microglia-driven inflammation contributes to post-injury sleep dysregulation and that the timing of microglial depletion and repopulation critically shapes recovery.
Adult male and female C57BL/6J mice (n = 49) underwent 14 days of sleep disruption followed by midline fluid percussion injury (mFPI) or sham surgery. Microglial populations were manipulated using the CSF1R inhibitor PLX5622, with depletion or repopulation timed relative to injury to test therapeutic windows of microglial activity. Mice were randomized by sex and assigned to Control, Depletion, or Repopulation groups. Sleep was continuously monitored for seven days post-injury using noninvasive piezoelectric cages.
Total sleep time during the first post-injury week showed a significant diet × injury interaction (p = 0.002), indicating that the effects of microglial manipulation depended on injury status. Across injury conditions, mice in the repopulation group exhibited significantly reduced total sleep compared with control and depletion groups (p = 0.032).
Behavioral performance assessed one-week post-injury using Barnes Maze, Open Field, and Novel Object Recognition revealed significant effects of time across all parameters (p < 0.0001).
These findings demonstrate that microglial activity exerts time-dependent effects on post-injury sleep regulation, and that microglial repopulation may impair sleep recovery following TBI. Together, these results support neuroinflammation as a modifiable driver of sleep dysregulation after brain injury and highlight the timing of immune interventions as a critical determinant of recovery.
Neuroinflammatory and Neurovascular Injury Blood Biomarkers Associated with Hyperglycemia in Traumatic Brain Injury (TBI)
1TBI Research Initiative, Philadelphia, United States, 2University of Pennsylvania, Philadelphia, United States
Objective: Hyperglycemia has long been recognized as being associated with poor outcomes after TBI and other acute neurologic insults. We hypothesized that hyperglycemia is related to neuroinflammation and microvascular injury.
Methods: Serum glucose was measured from blood obtained upon presentation to the emergency department for TBI. Hyperglycemia was defined as >125 mg/dL. Blood for biomarker levels was collected within 24 hours of injury, centrifuged within 1 hour, and stored at -80°C until assayed. Neurodegenerative (Neurology Panel 1), vascular injury (vascular injury panels 1 and 2, angiogenesis panel 1), and neuroinflammatory (cytokine panel 1, chemokine panel 1, and proinflammatory panel 1) proteins were measured on plasma using Meso Scale Diagnostics V-Plex and S-Plex panels. Biomarker levels were analyzed using Mann-Whitney U test and False Discovery Rate (FDR) corrected for multiple comparisons.
Results: 76 participants with non-penetrating TBI (mean age 43.2 years, 79% male, median Glasgow Come Scale (GCS) score 13) were included in analyses. 43 (57%) had hyperglycemia. There was a statistically significant difference between glucose groups in GFAP (Z=-2.218, p = 0.027), NfL (Z=-1.996, p=0.046), Tau (Z=-3.013, p=0.003), IFNgamma (Z=2.269, p=0.023), SAA (Z=-2.958, p=0.003), CRP (Z=-2.405, p=0.016), ICAM3 (Z=2.824, p=0.005), Eselectin (Z=2.29, p=0.022), VEGFD (Z=3.153, p=0.002), IL16 (Z=-2.552, p=0.011), and TNFbeta (Z=2.656, p = 0.008). Only Tau (q=0.045), SAA (q=0.045), and VEGFD (q=0.045) survived FDR correction.
Conclusion: Hyperglycemia after TBI is modestly associated with neuroinflammatory, microvascular, and neurodegenerative blood biomarkers. Future research with larger samples sizes will be needed to determine the mechanisms behind these associations.
Neurological Blood-Based Biomarkers of Chronic Exposure to Intimate Partner Violence Caused Brain Injury – Preliminary Study
1University of British Columbia, Vancouver, Canada, 2University of British Columbia Okanagan, Kelowna, Canada, 3Fraser Health Authority, Surrey, Canada, 4Supporting Survivors of Abuse and Brain Injury through Research (SOAR), Vernon, Canada, 5Vancouver Island University, Nanaimo, Canada
One in three women experiences intimate partner violence (IPV), which can cause brain injury (BI) through head/face/neck trauma and/or non-fatal strangulation. IPV-caused BI (IPV-BI) is often repetitive, yet the consequences of chronic exposure remain poorly understood. We examined whether blood-based biomarkers can characterize chronic IPV-BI in community-recruited survivors.
Plasma biomarkers from 40 female chronic survivors of IPV-BI (>6 months post-incident; mean age=38.8 (7.7) years) were profiled using the 131-plex NULISA Central-Nervous-System panel. Lifetime IPV-BI exposure was quantified via the Brain Injury Severity Assessment (BISA; frequency, recency, severity; mean BISA=3.4(1.4), range=1-8). After quality control (QC), biomarker co-expression modules were identified by hierarchical clustering with dynamic tree cutting (deepSplit=2; minimum size=12) and summarised by eigengene (first principal component). Linear regression tested eigengene-BISA associations adjusting for age and APOE4 carriership (p<0.05). Gene Ontology Biological Process enrichment was assessed via the full STRING network (Benjamini–Hochberg FDR<0.05).
120 biomarkers passed QC, resulting in seven co-expression modules (12–26 biomarkers each). Modules 2 and 3 were significantly associated with BISA (Module 2: beta=0.44, p=0.048; Module 3: beta=0.61, p=0.021). Module 2’s top biomarkers included RE1-Silencing Transcription Factor, Interleukin-6, and Intercellular Adhesion Molecule-1, with enrichment mainly in inflammatory pathways. Module 3′s top biomarkers were Amyloid Beta-40, Neuronal Pentraxin-1, Beta-Secretase-1, enriched for Amyloid precursor protein metabolic process, Glial cell proliferation, and Regulation of postsynaptic neurotransmitter receptor activity.
Chronic IPV-BI is associated with proteopathic, neuroinflammatory, and synaptic dysfunction signatures. Future studies should validate these findings in larger cohorts and assess biomarker links to long-term cognitive outcomes and comorbidities.
Neuronal Circular RNA: A New Class of Non-coding RNAs Regulating Repair After TBI
1Ulm University, Ulm, Germany
Circular RNAs are new non-coding RNAs involved in RNA-only regulatory pathways that include also microRNA and mRNA. Multiple circRNAs are upregulated upon TBI in human and mouse tissue, with distinct kinetics, peaking in the acute (3h) or subacute (7d) phase. The Khlh2-circRNA is highly expressed and localized in synapses of hippocampal neurons and independently regulated from the linear counterpart. Overexpression of Khlh2 accelerates the recovery of behavioural alterations, whereas suppression of Khlh2 aggravates the deficits. Khlh2 interferes with the activity of multiple microRNAs, all converging on the regulation of BDNF; in fact, overexpression of circ-Khlh2 increases BDNF levels in hippocampus with a cell-autonomous modality. Axonal growth and synaptic stability are enhanced by circ-Khlh2 but these effects are blocked by TrkB inhibition. Our findings reveal a new class of non-coding mechanisms involved in the repair phase of TBI.
Neuronal Dysfunction and Cognitive Deficits after Brain Injury are Associated with Increased Phosphatase and Tensin Homolog Activation in Cortical Neurons
1The Ohio State University, Columbus, United States
Cognitive impairment can develop in the years after traumatic brain injury (TBI), negatively affecting health span. We reported that TBI in mice increased inflammation and suppressed pathways in cortical neurons associated with homeostasis and plasticity 7 dpi. Moreover, microglial elimination (PLX5622) and stimulator of interferon genes (STING) ablation in microglia (mSTING-/-) prevented the TBI-induced neuronal and cognitive impairments. Thus, we sought to determine shared pathways between these interventions and determine new targets to improve neuronal homeostasis after TBI. Integration of two snRNA-seq experiments shows that the phosphatase and tensin homolog (PTEN) was enhanced by TBI in cortical neurons and prevented by both microglial and STING-related interventions. Moreover, genes associated with PTEN were increased (Pten, Gsk3b, Rock1/2) after TBI while genes associated with the Phosphoinositide 3-kinase (PI3K) growth and survival pathway (Akt3, Igf1r, Mapk1) were suppressed. Next, neuronal culture experiments confirmed neuronal expression of the IFNaR and sensitivity to IFN stimulation. Next, we aimed to inhibit PTEN after TBI using bisperoxovanadium (BPV). At 7 dpi, PTEN protein was increased in cortical neurons, and this was attenuated by BPV. TBI increased inflammation and reactivity of cortical astrocytes and microglia 7 dpi but only increases in rod-shaped microglia were PTEN dependent. Moreover, TBI-induced cognitive deficits at 7 dpi in the novel object location/recognition were blocked by PTEN inhibition. In addition, TBI-induced reductions in cortical NeuN+ were attenuated by PTEN inhibition. Collectively, PTEN was active in cortical neurons after TBI, was linked to microglial/interferon responses, and PTEN inhibition reduced neuronal dysfunction and cognitive impairment.
Neuronal LRP1 Deletion Mitigates Lipid-Peroxidation Driven Mitochondrial Dysfunction and Preserves Metabolic Flexibility in TBI
Dr Hemendra Vekaria1, Scout Grimes1, Frances Meredith1, Erin Sullivan1, Dr. Patrick Sullivan1,
1University Of Kentucky, Lexington, United States
Traumatic brain injury (TBI) triggers profound metabolic dysfunction driven by oxidative lipid damage and mitochondrial failure. Low-density lipoprotein receptor–related protein 1 (LRP1) is a multifunctional endocytic receptor expressed in several cell types, including neurons, that regulates lipid trafficking, inflammatory signaling, and metabolic homeostasis. Our previous studies demonstrated that LRP1-deficient fibroblasts exhibit resistance to oxidative stress–induced mitochondrial dysfunction. Based on these observations, we tested whether neuronal LRP1 deletion confers protection against metabolic injury following TBI.
We generated neuron-specific LRP1 knockout (NLKO) mice and subjected them to controlled cortical impact (CCI). Immunostaining, Western blotting, and mitochondrial bioenergetic analyses revealed significant mitochondrial dysfunction in WT mice 24 hours post-injury. In contrast, NLKO mice maintained mitochondrial respiratory capacity. Consistently, mitochondrial complex proteins were altered in injured WT mice.
To further examine mitochondrial dynamics, we generated Cre-inducible neuron-specific mitochondrial reporter mice expressing Dendra2-green (mtD2g) in the NLKO background (NLKO-NmtD2). WT mice displayed pronounced mitochondrial fragmentation and increased lipid peroxidation (4HNE), whereas these alterations were reduced in NLKO-NmtD2 mice. Transcriptomic profiling revealed that NLKO mice maintain expression of genes associated with mitochondrial respiratory complexes, the TCA cycle, and glucose metabolism, while inflammatory pathway genes were reduced following TBI. Complementary in vitro studies showed that LRP1-deficient fibroblasts resist lipid peroxidation–induced mitochondrial fragmentation and respiratory decline, with lipidomics confirming reduced lipid remodeling.
Together, these findings identify neuronal LRP1 as a stress-responsive amplifier of lipid-mediated mitochondrial injury and inflammation. Targeting LRP1-dependent lipid remodeling may represent a novel strategy to preserve metabolic function and improve neurological outcomes following TBI.
Neuronal LRP1 Regulates TBI-Induced TNFR1 Translocation, Activity and Amyloidosis
1Virginia Commonwealth University, Richmond, United States
Introduction: Low-density lipoprotein receptor-related protein 1 (LRP1) is a cell surface receptor for apolipoprotein E (ApoE), whose apoE4 isoform is a well-established risk factor for Alzheimer’s disease (AD). In vitro studies have demonstrated an anti-inflammatory role of LRP1 through internalization of TNFR1, the receptor for tumor necrosis factor (TNF). TBI upregulates TNF and TNFR1 acutely post-injury, alongside its downstream signaling pathways, resulting in increased levels of amyloid-β, a key pathology of AD. The role of LRP1 in vivo under injury conditions remains unknown.
Methods: Adult WT, ApoE4 and neuronal LRP1 knockout (CamKIIaCreERT2xLRPfl/fl) mice underwent a moderate TBI (controlled cortical impact) or sham-injury and were survived to 12 hours or 7 days post-injury. Ipsilateral hemisphere (flow cytometry) or hippocampus (Western blotting) was collected and processed to quantitate TNFR1 total and surface expression, as well as TNFR1 activity (NFΚB) and amyloidogenic (APP, amyloid-β) proteins. Animals underwent the Barnes Maze (learning 4-6DPI, probe 7DPI) to assess cognition.
Results: Flow cytometry reveals that ApoE4 mice have increased membranous TNFR1 levels, compared to WT, independent of injury. Comparatively, nLRP1 KO mice have significantly increased surface TNFR1 levels by 7DPI, which pairs with increased total TNFR1 levels detected by WBing. WBing also reveals that injury increases TNFR1 activity (NFΚB) in WT mice, but not in ApoE4 or nLRP1 KO. Conversely, injury only increases Aβ1-40 levels in ApoE4 and nLRP1 KO mice. Trends were observed for impaired cognition in nLRP1 KO mice.
Conclusion: These findings suggest that neuronal LRP1 regulates TNFR1 localization and activity, promoting amyloidosis.
Neuronal p38α Knockout Protects Against Neurological Consequences Following Repetitive Mild Traumatic Brain Injury
Dr. Chenxing Li1,2, Sydney Triplett2, Martin Griffin1,2, Abigail Holberton1, Adnan Kadragic1, Felix Rivera Moctezuma1, Sia Saheba1, Paul Saah2, Paul Sanz2, Janie Lee1, Rohan Wadhwani1, Drew Dawson1, Sophie Lunt1, Maya Chigurupati1, Erin Buckley1,2,3,
1Georgia Institute of Technology, Atlanta, United States, 2Emory University, Atlanta, United States, 3Children's Healthcare of Atlanta, Atlanta, United States
Mild traumatic brain injuries (mTBI) can substantially impact quality of life, and repetitive mTBIs (rmTBI) can amplify injury effects compared to a single injury. However, effective clinical treatments remain elusive, largely due to an incomplete understanding of the underlying injury mechanisms. Neuroinflammation has emerged as a key contributor to worse functional outcomes after mTBI/rmTBI. While microglia are traditionally viewed as primary mediators of post-injury inflammation, accumulating evidence suggests neurons play an immunomodulatory role in initiating the rmTBI inflammatory cascade through activation of intracellular proinflammatory pathways like p38 MAPK and secretion of cytokines that, in turn, stimulate microglial activation. Here, we tested whether inducible neuronal p38α knockout protects against functional, immune, and cerebrovascular consequences of a weight-drop closed head injury model of rmTBI. A battery of functional assays were conducted 4 weeks post-injury, and tissues were collected at both 4 hours and 4 weeks following final CHI. In males, neuronal p38α knockout protected against injury-induced depressive-like behavior, hyperactivity, synaptic loss, microglial reactivity, cytokine upregulation, and reduction in cerebral blood flow. In females, neuronal p38α knockout protected against risk-taking behavior and partially protected against cytokine upregulation but had limited effect on microglial reactivity and cerebral blood flow. Together, these findings identify neuronal p38α as a sex-dependent driver of rmTBI-associated neurological consequences, and they support neuronal p38α-immune signaling as a mechanistically relevant therapeutic target for future studies.
Neuronal TLR4 Signaling Compromises Dentate Granule Cell Physiology After Brain Injury by Upregulating MMP-9 Activity
1University of California - Riverside, Riverside, United States
Introduction: Traumatic brain injury (TBI) initiates a complex inflammatory cascade that exacerbates cellular damage and neurological dysfunction. We previously showed that upregulated Toll-like Receptor 4 (TLR4) signaling promotes epileptogenesis and cognitive impairments after TBI. However, the precise mechanisms by which TLR4 influences neuronal excitability remains unclear. This study investigates how TLR4 regulates Matrix Metalloproteinase-9 (MMP-9) activity in the Dentate Gyrus (DG) following brain injury, and its impact on dentate granule cell (DGC) physiology.
Material and Methods: Adult (8–10 week) TLR4fl/fl;CamKIIα-CreERT2 mice received lateral fluid percussion injury (FPI, 1.5 atm) or sham injury. Tamoxifen-induced neuronal TLR4 deletion was confirmed by immunohistochemistry. Cre-ve mice served as controls. MMP-9 activity was assessed 48h post-FPI using in situ zymography. One-week post-FPI, ex vivo electrophysiological recordings (300µm, coronal) evaluated DGC intrinsic properties and spontaneous excitatory postsynaptic currents (sEPSCs). The MMP-9 inhibitor SB-3CT (50mg/kg, i.p.) was used to test the TLR4:MMP-9 axis.
Results: MMP-9 activity increased in the DG of Cre- mice 48h post-FPI but was attenuated in Cre+ mice (P<0.05, TW-ANOVA). DGC intrinsic properties (capacitance, input resistance, rheobase) were similar across groups, though Cre+ FPI DGCs exhibited depolarized resting membrane potentials. Cre+ sham DGCs showed lower capacitance and firing frequency than shams, suggesting a basal role for TLR4. While FPI increased sEPSC frequency (reduced interevent intervals) in Cre-ve mice (P<0.0001, K.S. test), this effect was absent in Cre+ mice and prevented by SB-3CT treatment.
Conclusions: These findings identify a novel TLR4 mediated upregulation of MMP-9 activity that alters DGC physiology early after injury.
Neuronal-Induced Human Mesenchymal Stem Cells Improves Functional Recovery of Acute Spinal Cord Injury through Attenuating Neurotoxic Astrocyte Activation
1Kangwon National University, Chuncheon, Republic of Korea, 2Sungkyunkwan University School of Medicine, Seoul, Republic of Korea, 3Chonnam National University Medical School, Hwasun, Republic of Korea, 4Seoul National University, Seoul, Republic of Korea
Objective: Although mesenchymal stem cells (MSCs) have been widely studied on Spinal cord injury (SCI), their role remains unclear on astrogliosis of SCI. We previously reported that MSCs improved the functional outcomes of SCI by modulating acute astrogliosis.15). The present study aimed to elucidate the mechanisms on reactive astrocyte phenotypes and their influence is continuing in the chronic phase of SCI.
Methods: Neural-induced human adipose tissue-derived MSCs (NI-hADSCs) transplanted into the peri-lesional spinal cord at acute severe SCI model of rat. Functional recovery evaluated serially at postoperative 1 day and weekly thereafter for 6 weeks using the Basso-Beattie-Bresnahan (BBB) locomotor rating scale. Western blot analysis performed to assess protein levels of gliosis markers and neuroinflammatory pathways at 6 weeks post-injury. Histopathological examination conducted at 6 weeks post-injury to evaluate astrogliosis and astrocyte phenotypic changes.
Results: Transplantation of NI-hADSCs improved functional outcomes in the MSC-treated group. Protein levels of GFAP, vimentin, C3, and pSTAT3/STAT3, but not S100A10 and pNF-κB/NF-κB, significantly decreased in the MSC-treated group at 6 weeks post-injury. Immunohistochemical analysis revealed decreased astrogliosis and reduced C3-expressing astrocytes. However, these effects were limited to the dorsal aspect of the peri-lesional spinal cord. Significantly decreased Bax expression and increased Bcl-2 expression indicated that NI-hADSC treatment reduced neuronal apoptosis.
Conclusion: NI-hADSC transplantation can modulate astrogliosis and support functional recovery in SCI by suppressing detrimental A1 astrocytes, potentially through STAT3 signaling. However, stem cell transplantation during the acute phase of SCI yields spatially restricted effects at chronic SCI.
Neuropathology and immunohistochemistry analyses in post-mortem penetrating brain injuries (PBI) brains
Dr Grace Zhai1, Ms Jiaqi Liu1, Dr Liana Kozanno2, Dr Peter Pytel2,
1University of Chicago, Department of Neurology, Chicago, United States, 2University of Chicago, Department of Pathology, Chicago, United States, 3University of Chicago, Department of Neurosurgery, Chicago, United States, 4Cook County Medical Examiner Office, Chicago, United States
Background/Objective: PBI is one of the most devasting forms of brain injury and has mortality rates ranging from 23-92%. This heterogeneity underscores variability in injury mechanisms and tissue responses beyond projectile trajectory. We aim to use immunofluorescence staining of post-mortem brain tissue to evaluate CNS injury at the cellular and molecular level.
Methods: We selected the most proximal and most distal regions in post-mortem self-inflicted PBI brains, and corresponding regions in control patients. The selected blocks were sectioned and processed for immunofluorescence analysis using antibodies for glial fibrillary acidic protein (GFAP), S100B, DAPI and neurofilament light chain (NfL). Protein level and localization were analyzed using Fiji/ImageJ with measurement parameters set to quantify the area, intensity, and density.
Results: One PBI brain (23 y/o M, expired 37 minutes after EMS dispatch notification) and one control brain (31 y/o F, expired without neurologic injury) were stained. We observed a significant increase of GFAP signal in the grey matter area indicating astrocyte toxicity. In contrast, in the white matter area, GFAP signal intensity is modestly reduced with a fragmented morphology.
Conclusion: There is significantly increased GFAP and S100B expression in PBI brain compared to control suggesting astrogliosis response in the tissue distal to the injury site. Our findings provide the first insight to the global cellular changes responding to the PBI.
Newfound Axonal Pathology Phenotypes in Blast Traumatic Brain Injury
1University of Pennsylvania, Philadelphia, United States, 2Duke University, Durham, United States, 3Queen Elizabeth University Hospital, Glasgow, United Kingdom, 4Wayne State University, Detroit, United States
Blast traumatic brain injury (TBI) is highly prevalent among military personnel deployed in modern conflicts, with most cases classified as mild TBI or concussion. Despite being first described in a case series more than a century ago, the underlying neuropathology produced by blast exposure remains poorly defined. Here, we used a swine model to characterize axonal pathology following primary blast exposure (peak overpressure of 284 kPa, positive phase duration of 3.85 ms) generated using a compressed-gas shock tube. Compared with sham controls, we observed only infrequent amyloid precursor protein (APP) positive axonal swellings consistent with impaired axonal transport acutely (up to 5 hrs) after injury. In contrast, blast exposure produced extensive immunoreactivity for the calpain-derived alpha-II spectrin N-terminal fragment (SNTF) throughout white matter axons, indicative of ongoing axonal cytoskeletal proteolysis and degeneration. Notably, SNTF accumulation was frequently accompanied by widespread disruption of sodium channels (NaCh), with some axons showing complete NaCh loss. These findings suggest that calcium-dependent activation of calpain and subsequent axonal protein cleavage may be a key pathological substrate of blast injury. Further, we found that the patterns of diffuse axonal pathologies after blast exposure, marked by numerous SNTF+ axons with confluent or patchy distributions and minimal swellings, appear distinct from the fewer SNTF but more frequent mechanically deformed axonal transport interruptions and varicosities characteristic of non-blast, rotational acceleration injury. Together, this study identifies newfound phenotypes of axonal pathology in blast TBI and provides insight into the mechanisms of diffuse axonal injury associated with blast exposure.
NLRP3 Inflammasome Is Involved in Mediating Cerebral Vascular Integrity Following Traumatic Brain Injury in the Context of Predisposition of AD
Catherine Schivitz1, Dr. Jakob Green1, Sarah Timis1, Christopher Nelson1,
1Virginia Commonwealth University, Richmond, US
Traumatic brain injury (TBI) is a significant risk factor for the development of Alzheimer’s disease (AD). In both TBI and AD, inflammation plays a pivotal role. NLRP3 inflammasome is a key regulator of innate immunity playing an important role in inflammatory response in both TBI and AD. It is known that cerebral endothelial cells (ECs) lining the blood–brain barrier express NLRP3 inflammasome and with increased expression following inflammatory stimulation. ECs are at the interface of the immune and brain with important pathogenic role in both TBI and AD. In this study, we examined the role of NLRP3 in the process of vascular remodeling following TBI in the predisposition of AD using a novel transgenic AD mouse line with NLRP3 gene deletion. Briefly, a group of male and female 3xTg and 3xTg/NLRP3-/- mice received a moderate central fluid percussive injury or sham at the age of 4 months old before the onset of AD. At 7 days post-injury, we evaluated the protein expression levels of cerebral vascular associated proteins including GFAP, AQP4, CD31, Occludin in cerebral cortex and hippocampus with Western blot analysis. Changes of these proteins in relation to injury, NLRP3 and sex were found. Our study has confirmed that TBI significantly alters vascular integrity in the context of predisposition of AD and the NLRP3 inflammasome is important in mediating these TBI-induced changes with significant sex-related differences. Sponsored by Virginia Commonwealth Health Research Board grant (#236-12-25).
Novel Haloalkylated Human 18 kDa Translocator Protein Tracers for High-Accuracy Traumatic Brain Injury Diagnostics
Mr. Dhruv Subramanian1
1The Quarry Lane School, Dublin, United States
Traumatic brain injury (TBI) associated neuroinflammation, which affects over 50 million worldwide, progresses from acute (<72 hours) to chronic phases across three cellular sources. Current tracers in human 18kDa translocator protein (TSPO) PET imaging are inadequate because of low blood-brain barrier (BBB) permeability and high nonspecific binding in brain tissue, leading to inaccurate neuroinflammation diagnoses in the acute phase. This results in suboptimal patient outcomes. I have developed a novel TSPO PET tracer that incorporates haloalkyl side chains with improved BBB permeability in TBI using a multimodal computational architecture.
Eight existing TSPO tracers were ranked through z-score normalization, with emapunil (AC-5216) emerging as the highest-ranked tracer. Emapunil was systematically modified using targeted haloalkylation for two functional groups, with the third being kept as a control. A library of 1,922 analogs was generated and evaluated for highest docking energy through CNS-MPO. Finally, 17 lead candidates were evaluated for partition coefficients (Kp) and brain-plasma ratios; simulated PET kinetics were calculated via plasma-input graphical Logan analysis to derive volume of distribution (VT).
All 17 candidates were haloalkylated, of which 15 contained a fluorinated side chain, thus validating the hypothesis that haloalkylation improves brain partitioning in TSPO PET. Pharmacokinetic simulations showed 5.4x improvements in Kp and 4x improvements in brain-plasma ratio compared to emapunil, indicating increased BBB permeability. VT estimates for all analogs stayed consistent across all t* values, validating PET kinetic feasibility. These findings affirm that haloalkylated TSPO tracer candidates improve BBB permeability and PET kinetics associated with TBI neuroinflammation diagnosis.
Novel Handheld Intracranial Hemorrhage Detection and Treatment Devices Designed for Prolonged Field Care Use Assessed in a Sheep Model of Life-threatening Subdural Hematoma
Dr. David Brody1
1USUHS, Bethesda, United States
Traumatic subdural hemorrhage (SDH) mortality can be up to 50%. Early detection and surgical intervention improve outcomes. In armed conflict with a peer or near-peer adversary, severe injuries are expected to be more common than in recent wars, and casualty care will be complicated by delayed medical evacuation. Therefore, development of improved pre-hospital and prolonged field care is a current priority. In this context, large animal models of life-threatening SDH may allow assessment of new prehospital diagnostic and therapeutic approaches. We modeled SDH in sheep with infusion of autologous blood into the subdural space. Sheep are an appropriate species because their skull thickness is similar to humans. Mortality was low with 10 ml (0/3), low with 12 ml (1/6), at 50% with 15 ml (3/6) and 100% with 20 ml (3/3) of subdural blood infusion. Neurological function was impaired for up to 72h in surviving sheep. After 15 ml of blood infusion, ICP increased significantly to 114 ± 42 mm Hg. There were irregular elevations in blood pressure and variable heart rate responses during subdural blood infusion, consistent with Cushing response. Post-mortem CT scans, necropsy, and histological evaluation revealed intracranial hemorrhage, cellular necrosis, and early inflammatory responses. The sheep model is being used to test a novel hand-held infrared-based intracranial hemorrhage detection device and a novel field-adapted intracranial hemorrhage treatment device designed for non-neurosurgeons. In summary, the sheep model of life-threatening SDH has potential to assist with preparation for severe TBI in large-scale combat operations and other austere environments.
Observable Signs of Concussion in Professional Slap Fighting Using Established Video Review Protocols for Professional Sports
1Neuroscience Graduate Program - University of Michigan, Ann Arbor, United States, 2Physical
Medicine and Rehabilitation - University of Michigan, Ann Arbor, United States, 3Concussion Center - University of Michigan, Ann Arbor, United States, 4Elson S. College of Medicine - Washington State University, Spokane, United States, 5Health Sciences - Thompson Rivers University, Kamloops, Canada, 6Emergency Medical Services - Alberta Health Services, Calgary, Canada, 7Southern Medical Program - University of British Columbia Okanagan, Kelowna, Canada, 8Veterans Administration Ann Arbor Health Care System, Ann Arbor, United States
Concussion is a traumatic brain injury (TBI) with potential short- and long-term neurological consequences. Recognition of objective concussion signs remains limited. In slap fighting, a combat sport involving defenseless head contact, concussion signs are visible. The study objective was to examine the frequency of observable signs of concussion among professional slap fighters using established video review protocols and determine whether participant characteristics predict concussion signs. Three independent reviewers evaluated publicly available video of professional slap fighting events (Power Slap™; 2023-2024) against the National Football League Concussion Protocol, the World Rugby Head Injury Assessment, and International Consensus Guidelines for observable signs of concussion. Signs were recorded for each strike and aggregated across rounds, matches, events, and combatants. Mixed-effects logistic regression evaluated associations between pre-slap characteristics and the likelihood of observing a sign of concussion following a strike. Combatants (60 male, 3 female) competed across 62 matches in six Power Slap™ events. Of the 61 combatants who received a strike, 46 exhibited at least one sign of concussion. Overall, 29% (82/280) of strikes resulted in at least one observable sign of concussion, with lower prevalence across protocol guidelines (24%; 66/280). Motor incoordination (23%; 64/280), blank/vacant look (15%; 41/280), and slow to get up (14%; 40/280) were the most frequently observed signs. Observable signs of concussion in professional slap fighting occurred in one-third of strikes and most matches. Increased awareness of observable signs of concussion in slap fighting may enhance recognition in athletic and societal settings.
Older Veterans Presenting to a VA Emergency Department versus Patients Presenting to Trauma Centers with Acute Traumatic Brain Injury (TBI)
1University of California San Francisco, San Francisco, United States, 2Sheba Medical Center, Tel Hashomer, Israel, 3University of Pittsburgh, Pittsburgh, United States
Background: Older Veterans (aged 65+ years) are underrepresented in acute traumatic brain injury (TBI) research. The demographic, comorbidity, and clinical profiles of older Veterans are not well described and may be distinct from those of the elderly in the general population.
Methods: Data are compared between two cohort studies: TRACK-VA, N=70 older Veterans presenting to one VA ED; TRACK-GERI, N=240 older Adults presenting to a Level 1 Trauma Center; and the National Trauma Data Bank (NTDB), which includes data from TBI patients presenting to Trauma Centers from 2017-2024. Baseline demographics, pre-injury health, and injury features were compared between groups using t-test for continuous variables and chi-squared tests for categorical variables.
Results: Across TRACK-VA, TRACK-GERI, and NTDB, there was a similar prevalence of alcohol use disorder. Comparing TRACK-VA versus TRACK-GERI showed similar prevalence of dementia and presenting GCS score of 13-15, but higher prevalence of pre-existing TBI. TRACK-VA had a higher prevalence of dementia than NTDB, and higher prevalence of psychiatric conditions, PTSD, and lower prevalence of hospital admission than both TRACK-GERI and NTDB.
Conclusion: Older Veterans showed significantly higher rates of psychiatric disorders and PTSD than patients in other cohorts. The similarity of alcohol use disorder across groups may show a commonality across TBI patient populations. Older Veterans enrolled in a single-center VA ED study of acute TBI are a particularly vulnerable population whose unique comorbidities prevent them from adequate representation in current TBI research. Larger multi-center VA-ED studies of older Veterans with acute TBI are indicated.
Optical Characterization of Cerebral Pulsatility During Postural Intracranial Pressure Changes: A Feasibility Study
1Western University, London, Canada, 2Lawson Research Institute, London, Canada, 3University of Toronto, Toronto, Canada
Hemodynamic pulsations carry rich information about cerebrovascular health as their shapes reflect characteristics of the vascular wall, blood pressure, pulse wave reflections, and intracranial pressure. Consequently, assessing these waveforms can serve as a potential biomarker of hemodynamic dysregulation and possibly injury. This work assessed the feasibility of using an in-house-built optical system combining near-infrared spectroscopy (NIRS) with diffuse correlation spectroscopy (DCS) to measure pulsatile components related to cerebral blood volume and flow, respectively. Our system incorporates depth-enhanced optical technology to increase sensitivity to cerebral tissue. The ability to detect changes in waveform morphology with this non-invasive hybrid technology was evaluated by inducing postural intracranial pressure changes.
Data were collected in 10 healthy adults while standing and lying down (30±7 years, 5 female). Pulsatile waveforms were extracted through an in-house-built pipeline (MATLAB; PulseStudio). For comparison, transcranial Doppler ultrasound (TCD) was used to measure blood velocity in the middle cerebral artery.
Pulse amplitude declined with standing for TCD (p < 0.05; paired t-test), DCS (p < 0.005), and NIRS (p < 0.01). Further, DCS and NIRS waveforms exhibited distinct shapes reflecting their sensitivity to different vascular components: DCS captures blood flow pulsation in the smallest arteriole branches, whereas NIRS reflects arterial and venous blood volume changes, which are influenced by intracranial pressure. These findings suggest that hybrid optical monitoring captures complementary pulsatile dynamics across vascular compartments, supporting the development of non-invasive approaches for monitoring intracranial pressure and cerebrovascular function in brain injury.
Optogenetic Peripheral Nerve Stimulation for Motor Rehabilitation in Rodent Chronic Spinal Cord Injury Models
1Medical College of Wisconsin, Milwaukee, United States, 2Marquette University, Milwaukee, United States
Viral-mediated optogenetic peripheral motor nerve stimulation is an attractive tool for rehabilitating motor deficits in conditions such as spinal cord injury (SCI). This technique possesses a number of potential benefits over electrical stimulation including physiological motor unit recruitment and reduced fatigue. However, viral-mediated opsin expression via intramuscular injection has not been validated or optimized in chronic SCI models. In this study, we sought to compare timelines and levels of motor and sensory opsin expression in rat SCI models and non-injured rats. We performed thoracic SCIs in rats followed by a waiting period of 2-8 weeks and intramuscular AAV injection into the tibialis anterior muscle to target channelrhodopsin expression to the peroneal nerve. Weekly optical stimulation sessions were performed from 2-20 weeks after virus injection while recording electromyograms (EMG) from the injected muscle to evaluate functional opsin expression. Nerve samples were examined for opsin expression using immunohistochemistry at the conclusion of the experiment. We observed similar onset of optical sensitivity in the target nerve for all groups (2-6 weeks), and stimulation was able to evoke foot movements. Offset of functional optical sensitivity was variable across groups (8-20 weeks). H-wave analysis of optically stimulated responses revealed opsin expression in a small proportion of sensory axons, confirmed by histology. Overall, these results demonstrate that optogenetic protein expression in peripheral motor axons via intramuscular virus injection is feasible following chronic SCI, offering further support for optogenetic stimulation as a potential rehabilitation therapy for restoring movements.
Oscillating Hypercapnia Induces Neural Abundant Protein Efflux and Potential Depletion in Health and Chronic Traumatic Brain Injury
1Mind Research Network, Albuquerque, United States, 2University of New Mexico School of Medicine, Albuquerque, United States, 3Medical College of Wisconsin, Milwaukee, United States, 4University of Groningen, University Medical Center Groningen, Groningen, Netherlands, 5Boston Children’s Hospital, Boston, United States
Emerging preclinical and clinical evidence suggests that low frequency hemodynamic oscillations (LFHO) drive CSF flow, which in turn mediates glymphatic clearance. The current study investigated whether CO2-induced LFHO(24 cycles) during magnetic resonance imaging would increase clearance of neural abundant proteins (glial fibrillary acidic protein [GFAP], neurofilament light chain [NfL], ptau217 and brain-derived tau [BD tau]) from brain to blood, and temporarily improve cognitive control performance in individuals with chronic traumatic brain injury (TBI; N=22) and age/sex-matched healthy controls (N=22). Results indicated that cerebrovascular reactivity, normalized CSF volume, and predicted brain age significantly differed between chronic TBI and controls, whereas bulk CSF flow differed between groups only at trend levels. GFAP, NfL and BD tau concentrations were significantly increased at ∼45 minutes post-hypercapnia relative to a pre-hypercapnia sample. All proteins were decreased below pre-hypercapnia levels at ∼90 minutes and returned to baseline levels by ∼150 minutes. Total CSF volume and total white matter volume were uniquely associated (i.e., partial correlation) with GFAP, BD tau and ptau217 efflux, whereas cerebrovascular reactivity and bulk CSF flow were associated only with ptau217 efflux. Both groups exhibited reduced cognitive interference post-hypercapnia, and hypercapnia associated symptoms quickly returning to baseline levels. In conclusion, hypercapnia temporarily increases clearance of multiple neural abundant proteins into blood, and this effect is moderated by both atrophy (more prominent) and cerebrovascular functioning. Current results suggest that hypercapnia may therapeutically combat pathological protein aggregation post-trauma, and prophylactically during normal aging to reduce the likelihood of late developing pathologies including neurodegeneration.
Osmotic Transport Device Reduces Lesion Volume in a Rat Model of Penetrating Traumatic Brain Injury
Dr. Joseph Dwyer2,3, Dr. Alan Giglio1, Dr. Xiaofang Yang2,3, Dr. Ying Cao2,3, Dr. Zachary Bailey2, Dr. Alexandru Korotcov4,5,
1University of California, Riverside, United States, 2Walter Reed Army Institute of Research (WRAIR), Silver Springs, United States, 3The Geneva Foundation, Bethesda, United States, 4Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, United States, 5Biomedical Research Imaging Core at Uniformed Services University, Bethesda, United States
Background: Treatments for penetrating traumatic brain injuries (pTBI) represent a critical gap for battlefield point-of-injury care. This study evaluates a novel osmotic transport device (OTD) designed for such injury.
Methods: Acute and extended OTD treatment was evaluated in a rodent model of pTBI. Anesthetized adult male Sprague-Dawley rats experienced a right unilateral pTBI. Animals were assigned to: Sham, Injury only, and OTD with isotonic or hypertonic fluid and treated for either 4hr or 72hr post-injury. In acute (4hr) experiments, animals remained anesthetized and ICP was monitored throughout. Brain water content was measured using the wet-dry method. In extended (72hr) treatment, edema volume was characterized using MRI during and following a 72hr treatment for up to 7 days post-injury. Blood-based biomarker concentrations were measured following the treatment and post-injury histology was performed.
Results: Post-mortem histology revealed a statistically significant reduction in final lesion volume of OTD-treated subjects compared to an injury-only control (p = 0.0069). Also, histology showed significantly decreased IBA1 expression in the hippocampus (p = 0.0142) and striatum (p < 0.0001) contralateral to the injury. Other serum analysis revealed a trending decrease in biomarkers of neuronal and glial injury.
Conclusion: These findings indicate that the OTD is a promising candidate for pTBI treatment for point-of-injury treatment of pTBI. For both acute management of intracranial hypertension as well as providing long-term neuroprotective benefits by mitigating neuroinflammation and tissue loss.
Partial Restoration of Metabolic Network Connectivity in a Rat Blast TBI Model
1Uniformed Services University of the Health Sciences (USUHS), Bethesda, United States, 2The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, United States, 3The University of Warwick, Coventry, United Kingdom
Blast traumatic brain injury (bTBI) remains a critical concern for military personnel, yet targeted pharmacological strategies to restore function following bTBI remain limited. RibAdeAll (ribose, adenine, and allopurinol; RAA) is a purine salvage combination that enhances adenosine triphosphate (ATP) scavenging and has demonstrated neuroprotective effects in rodent stroke models. We investigated whether intravenous RAA administration following bTBI would preserve metabolic function and support behavioral recovery.
Sprague-Dawley rats with indwelling jugular vein catheters underwent repeated blast exposure (15–20 psi, once daily for 3 consecutive days) under isoflurane anesthesia or sham procedures. Immediately following the final blast, animals received intravenous RAA or vehicle infusion (n=6/group for imaging). Behavior was assessed across motor and cognitive domains over 30 days after the final injury. Positron emission tomography (18FDG-PET) was acquired at 24 hours post-injury, and metabolic connectivity was characterized using the Waxholm rat brain atlas across 222 regions.
Metabolic covariance mapping revealed blast-induced network disorganization and widespread regional depression relative to sham controls. RAA treatment did not globally normalize connectivity but produced marked thalamic hyperconnectivity in blast-exposed animals, a shift from the hypoconnectivity in Blast-Veh rats. Critically, auditory relay nuclei, olfactory circuitry, habenular-limbic pathways, and subcortical sensorimotor loops showed normalized connectivity strength in Blast+RAA animals where Blast+Vehicle remained aberrant. Both Sham+RAA and Blast+RAA animals also demonstrated enhanced learning on a reversal learning Y-maze task 21 days post-injury.
These results suggest RAA may support post-blast injury network reorganization by amplifying thalamic output to counteract blast-induced metabolic network depression.
Patterns of Spinal Fusion Utilization Following Vertebral Fractures Without Spinal Cord Injury: Insights from the National Trauma Data Bank
1Suny Downstate Health Sciences University, Brooklyn, United States, 2Icahn School of Medicine at Mount Sinai, New York, United States
Objective: Spinal fusion is frequently performed in the management of vertebral fractures, although large-scale studies describing factors linked to fusion utilization among patients without spinal cord injury (SCI) remain limited. This study examined characteristics associated with spinal fusion among adults with vertebral fractures without SCI from a national trauma database.
Methods: Adult patients (≥18 years) with cervical, thoracic, or lumbar fractures without SCI were identified in the National Trauma Data Bank from 2019–2021. Demographics, fracture location, and hospital course variables were analyzed. Multivariable logistic regression was performed to evaluate variables associated with spinal fusion, reported as adjusted odds ratios (aOR) with 95% confidence intervals (CI).
Results: A total of 378,504 patients were analyzed, with 35,792 (9.5%) undergoing spinal fusion. Female patients had lower odds of undergoing spinal fusion than male patients (aOR 0.84, 95% CI 0.82–0.86; p<0.001), and Black patients had lower odds compared with White patients (aOR 0.88, 95% CI 0.85–0.92; p<0.001). Fracture location showed the strongest association with fusion utilization. Patients with subaxial cervical fractures (C3–C7) had the highest odds of fusion (aOR 2.38, 95% CI 2.32–2.45; p<0.001), whereas lower lumbar fractures (L3–L5) had reduced odds (aOR 0.74, 95% CI 0.71–0.76; p<0.001). Patients with osteomyelitis also had increased odds of undergoing fusion (aOR 2.13, 95% CI 1.39–3.27; p=0.001).
Conclusion: Utilization of spinal fusion following vertebral fractures without SCI varies across demographic groups and fracture locations. These findings highlight patterns of operative management in non-SCI spinal trauma and may inform future evaluation of surgical decision-making in vertebral fracture care.
PDE2A Inhibition as a Therapeutic Strategy for Traumatic Brain Injury
1The Roskamp Institute, Inc., Sarasota, United States
Traumatic brain injury (TBI) is associated with increased risk of developing neurodegenerative diseases, yet no approved disease-modifying treatments exist. Phosphodiesterase-2A (PDE2A) is an enzyme that hydrolyses both cAMP and cGMP cyclic nucleotides, regulating signaling pathways involved in synaptic plasticity, neuroinflammation, and neuronal survival. Our preliminary data demonstrate that PDE2A is increased in the cortices of different mouse models of repetitive mild TBI, suggesting that PDE2A plays an important role in TBI pathogenesis. Gavage administration of a PDE2A inhibitor (PF-05) resulted in improved motor function, learning, and memory, and reduced neuroinflammation.
We have now investigated the effects of PF-05 administered in chow after injury, using two different TBI models - our 5-hit mTBI model (5r-mTBI) and a novel moderate-severe TBI model (msTBI). Analysis of PF-05-treated msTBI mice showed improved motor and cognitive function 21 days post-injury; pathological analyses of this cohort is ongoing. For the 5r-mTBI-treated mice, assessment at 1-month post-last injury showed a trend toward improved motor performance, particularly in females, and increased risk-taking behavior, as evidenced by increased open arm entries in the elevated plus maze. However, they did not show any improvement in memory performance. The same cohort is undergoing behavioral testing at a 6-month timepoint prior to euthanasia, and we will present the behavioral and pathological data.
Our data continue to support a role for PDE2A in TBI pathogenesis and the potential value of PDE2A inhibition, but more work is needed to confirm target engagement and assess the relationship between PDE2A inhibition and TBI pathogenesis.
PDGFRα-mTOR Signaling pathway Drives Reactive Astrocyte Proliferation and Supports Synaptic Remodeling in the Hippocampus After Traumatic Brain Injury
1Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, United States, 2Spinal Cord and Brain Injury Research Group, Stark Neuroscience Research Institute, Indianapolis, United States
Astrogliosis, characterized by astrocytic hypertrophy, proliferation, and transcriptional changes, is a hallmark response to traumatic brain injury (TBI). However, the signaling mechanisms regulating astrocyte proliferation and their functional significance, particularly in the hippocampus, a region distant from the injury site, remain poorly understood. In this study, we characterized the temporal dynamics of astrocyte activation and proliferation in the hippocampus following TBI and investigated signaling pathways regulating this response.
Using a mouse model of controlled cortical impact, we observed rapid astrocyte activation in the hippocampus, marked by increased glial fibrillary acidic protein expression and morphological hypertrophy as early as 4 h post-injury. Astrocyte proliferation emerged later, peaked at 48–72 h, and returned to baseline by 7 days post-injury, indicating a transient proliferative response. Mammalian target of rapamycin complex 1 signaling was strongly activated in reactive astrocytes and was preferentially associated with proliferating astrocytes after injury. Pharmacological inhibition of mTORC1 with rapamycin significantly reduced astrocyte proliferation without affecting hypertrophy.
We further identified platelet-derived growth factor receptor alpha as a key regulator of proliferative astrocytes. Triple immunostaining for PDGFRα, GFAP, and BrdU showed that 90.27% ± 3.83% of proliferating astrocytes expressed PDGFRα after TBI. Conditional deletion of PDGFRα reduced mTOR signaling and astrocyte proliferation, decreased synaptic density in the ipsilateral dentate gyrus, and increased impulsivity-like behavior in the elevated plus maze.
Together, these findings demonstrate that TBI induces a transient astrocyte proliferative response regulated by PDGFRα–mTORC1 signaling and suggest that proliferative astrocytes contribute to synaptic preservation and functional recovery after TBI.
Pediatric Traumatic Cerebral Venous Sinus Thrombosis: A Meta-Regression Analysis of Anticoagulation Practices in Hemorrhagic CVST
1University of Miami Department of Neurological Surgery, Miami, United States, 2University of Miami Department of Orthopaedic Surgery, Miami, United States
Traumatic cerebral venous sinus thrombosis (CVST) is an uncommon but increasingly recognized complication of pediatric head injury. Optimal management, particularly with concurrent intracranial hemorrhage, remains poorly defined, and anticoagulation remains controversial.
A systematic review of PubMed, Scopus, Embase, and the Cochrane Library identified studies reporting therapeutic management of pediatric CVST (2000-2024). Study-level proportions were extracted for traumatic etiology, hemorrhage type, anticoagulation use, and outcomes. Associations were evaluated using weighted least-squares meta-regression with sample-size weighting and Benjamini-Hochberg false discovery rate (FDR) correction.
Sixty-two studies comprising 7,859 pediatric patients from 23 countries were included, including fifteen trauma-focused cohorts. Across studies, 481 traumatic CVST cases were reported, with a median trauma-attributable proportion of 12.6% (IQR 7.3-35.7%). Trauma prevalence was associated with higher reported rates of intracranial hemorrhage (R2=0.603, β=0.571, FDR p<0.001), including subdural hemorrhage (SDH) (R2=0.844, β=0.300, FDR p<0.001) and subarachnoid hemorrhage (R2=0.713, β=0.149, FDR p<0.001). Hemorrhagic CVST was associated with greater anticoagulation withholding (median 25%, range 0-100%), particularly in studies with higher rates of intraparenchymal hemorrhage (R2=0.452, β=0.804, FDR p<0.001), hemorrhagic venous infarction (R2=0.396, β=0.694, FDR p=0.001), and SDH (R2=0.204, β=0.871, FDR p=0.035). Across studies, higher anticoagulation withholding was associated with increased mortality (β=0.140, R2=0.173, FDR p=0.007). Trauma and SDH were also associated with higher rates of recurrent thrombosis (trauma: R2=0.369, β=0.139, FDR p=0.008; SDH: R2=0.344, β=0.471, FDR p=0.021).
Trauma-associated pediatric CVST demonstrates a hemorrhagic phenotype associated with increased anticoagulation withholding and higher reported mortality. These findings highlight the need for prospective studies to clarify optimal anticoagulation strategies for pediatric traumatic CVST.
Perivascular Connexin 43 and Fibronectin expression is a Novel Signature of Interface Astroglial Scarring in a Gyrencephalic Model of Multi-Modal Traumatic Brain Injury
1Uniformed Services University of The Health Sciences, Bethesda, United States
Postmortem findings from U.S. Warfighters with extensive exposure histories to blast and impact reveal the presence of widespread brain scarring. These scarring patterns, demarcated by the presence of reactive astrocytes, occur in unique anatomical patterns linked to blast wave exposure. This phenotype, now known as Interface Astroglial Scarring (IAS), occurs in Layer 1 of the cerebral cortex, the gray/white matter interface, the sulcus of gyri, periventricular zones, and around blood vessels. Our lab developed and characterized a gyrencephalic model of IAS in the ferret by using a combined injury method of repeated blast and CHIMERA exposure. Our model recapitulates the hallmark features of IAS, most notably increases in Glial Fibrillary Acidic Protein (GFAP)+ astrocyte proliferation at sites of interface and a marked increase in Aquaporin 4 (AQP4) around blood vessels. Connexin 43 (CX43) and Fibronectin (FIB) are also biomarkers for astroglial scarring but have not been assessed in a gyrencephalic model of repeated blast and impact TBI. To this end, we investigated the expression profile of CX43 and FIB in conjunction with the canonical IAS biomarkers GFAP and AQP4 through double and triple-labeling immunohistochemistry and fluorescent microscopy of sham (N=3) and injured (N=6) ferret neocortex. We found a substantial increase of CX43 and Fibronectin labeling associated with AQP4+ blood vessels and GFAP + Astrogliosis at 4 weeks (n=3, 455% increase vs. sham, p = 0.034) and 6 months (n=3, 435% increase vs. sham, p = 0.008) post-injury, reinforcing previous reports of blood vessels being key sites of primary injury.
Persistent Cerebellar Pathology in a Gyrencephalic Animal Following Combination Blast-CHIMERA TBI
1Department of Anatomy, Physiology and Genetics, Uniformed Services University, Health Sciences, Bethesda, USA, 2The Military Traumatic Brain Injury Initiative (MTBI2), Bethesda, USA, 3The Henry M. Jackson Foundation Inc., Bethesda, USA
Military service members are often exposed to repetitive forces such as blast overpressure and rotational acceleration. To mimic the types of injuries observed in warfighters, adult male ferrets were exposed to a combination of repetitive injuries including blast and CHIMERA (Closed Head Injury Model of Engineered Rotational Acceleration) delivered over 2 weeks. Subjects then survived for 6 months (6MPI) post-injury. The cerebellum is materializing as a critical structure mediating multiple neural functions including cognition, sleep, and emotion, in addition to its role in integrating balance and coordination, highlighting the importance of understanding the effect of TBI on the cerebellum. We evaluated their cerebella, investigating the distribution of Purkinje cells and the molecular layer via Calbindin labeling. Subjects who received the most combined injuries, and had a prolonged survival showed a decrease in number of Purkinje cells (p=0.0176) and a dramatic decrease in molecular layer Calbindin expression (p=0.001) compared to sham. The loss of Purkinje cells and decrease in Calbindin expression was not evenly distributed across the cerebellar cortex, but clustered in lobules and sulci. We also document disruption to myelination (via MBP), and axons (via SMI-34) in the cerebellum. While individual variability existed within groups, a clear trend emerged: combined blast and rotational injuries correlates with persistent cerebellar neuropathology. These findings suggest that cumulative injury burden and extended post-injury duration could contribute to progressive cerebellar damage.
Persistent Post-concussion Symptoms Correspond to Lasting Axonal and Oligodendrocyte Damage in Repetitive mTBI
1Department of Neurology, University of Pittsburgh, Pittsburgh, United States, 2Pittsburgh Institute for Neurodegenerative Disorders, Pittsburgh, United States, 3Stonybrook University, Stony Brook, United States, 4Veterans Affairs Pittsburgh Health Care System, Geriatric Research Educational and Clinical Center, Pittsburgh, United States, 5Department of Cell Biology, University of Pittsburgh, Pittsburgh, United States, 6Animal Imaging Center, University of Pittsburgh, Pittsburgh, United States, 7Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States, 8Department of Human Genetics, University of Pittsburgh, Pittsburgh, United States, 9University of Pittsburgh School of Public Health, Pittsburgh, United States, 10Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, United States, 11Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, United States
Chronic post-concussion syndrome affects millions of repetitive mild traumatic brain injury (rmTBI) patients, but incomplete understanding of its etiology has limited therapeutic intervention. Recent neuroimaging studies show that chronic symptoms are closely associated with persistent brain demyelination; we hypothesize that rmTBI triggers prolonged oxidative stress/mitochondrial dysfunction that contributes to extended demyelination, impaired oligodendrocyte precursor cells (OPC) differentiation, and associated motor/cognitive function deficits. We investigate the role of Na+/H+ exchanger 1 (NHE1), a key regulator of NADPH oxidase reactive oxygen species generation, in mediating this pathogenesis.
Control (Pdgfra-creERTM-/-;Nhe1fl/fl) and conditional oligodendrocyte NHE1 cko (Pdgfra-creERTM+/-;Nhe1fl/fl) mice underwent five successive mTBI or sham surgeries (n=9-12/group). RmTBI induced transient motor deficits and sustained anxiety-like behavior on rotarod, open field and voluntary wheel running tests as late as 45-55 days post injury in control mice. Ex-vivo diffusion tensor MRI of these mice detected reduced corpus callosum integrity accompanied by decreased NF-L expression and degraded myelin accumulation compared to Sham cohorts. RmTBI controls also exhibited reduced oligodendrocyte counts despite an expansion of OPCs (p<0.05), accompanied by mitochondrial PINK1 protein accumulation and reduced cytochrome c oxidase (COX4) protein. In contrast, COX4 and PINK1 expression in the rmTBI cKO brains remained similar to Sham controls. OL-specific NHE1 cKO conferred resistance to rmTBI-mediated behavioral impairment, white matter damage and oligodendrocyte loss/OPC accumulation (p<0.05).
Our findings suggest that rmTBI-induced neurological deficits involve persistent white matter damage. Oligodendrocyte NOX2-NHE1 axis plays a role in mitochondrial oxidative stress pathogenesis and may present a therapeutic target for improving concussion recovery.
Perspectives on Minimally Acceptable Outcome After Severe Traumatic Brain Injury: A Qualitative Study
1Spaulding Rehabilitation, Charlestown, United States, 2MGH Institute of Health Professions, Boston, United States, 3Harvard Medical School, Boston, United States, 4Boston University School of Medicine, Boston, United States, 5Medical College of Wisconsin, Milwaukee, United States, 6Massachusetts General Hospital, Boston, United States, 7University of Stirling, Stirling, United Kingdom, 8Vanderbilt University Medical Center, Nashville, United States
Objective Explore: (1) perceptions about “minimally acceptable outcome” (MAO) after severe TBI (sTBI); (2) values and beliefs that influence medical decision-making among individuals with sTBI and caregivers.
Method: Qualitative descriptive design: semi-structured open-ended interviews were conducted. Participants with sTBI and caregivers (not paired) read vignettes describing a sTBI case requiring early medical decision-making and answered questions about MAO. Interviews were coded and themes were generated using reflexive thematic analysis.
Results: 15 persons with sTBI (53% female, x̄ = 47.2yrs), and 15 caregivers (73% female, x̄ = 56.3yrs), including parents (60%), siblings (20%), and spouses (20%) were interviewed. 4 themes were identified: (1) Active Participation: Both cohorts discussed the ability to be an active participant in one’s life is crucial for determining the acceptability of outcomes after sTBI but defined active participation differently (partial independence vs. basic communication). (2) “Final” Outcome: Participants struggled to identify an MAO because they did not perceive a “final” outcome, based on the potential for further recovery. (3) Early Decision-Making: Participants emphasized that life-altering decisions (including withdrawal of life-sustaining treatment) should not be made in days immediately following sTBI. (4) Playing God: Participants struggled with surrogate decision-making and were disinclined to “play God” for others.
Conclusion: Study results highlight the complex and deeply personal nature of defining MAO for persons with sTBI and caregivers. Findings emphasize the need for clinical tools that recognize changing recovery trajectories and assist people with both shared decision-making and navigating moral complexities of determining MAO.
Pharmacological Modulation of AMPK Limits Neuroinflammation, Improving Neurobehavioral Outcomes After TBI
1Department of Neurology, Henry Ford Health, Detroit, United States
Traumatic brain injury (TBI) is a major public health concern and a leading cause of mortality and long-term neurological disability worldwide. During physiological stress such as TBI, AMP-activated protein kinase (AMPK) acts as a critical cellular energy sensor that maintains metabolic homeostasis. Emerging evidence suggests that reduced AMPK phosphorylation after TBI disrupts cellular metabolic balance and promotes neuroinflammation; however, the mechanisms by which loss of AMPKα1 activity contributes to neurolopathology remain poorly understood. In this study, we investigated the neuropathological consequences of impaired AMPK signaling after TBI in mice. C57BL/6 mice-wild-type (WT) and AMPKα1 knockout (KO) were underwent TBI or sham surgery. Behavioral tests were conducted 72h post-TBI, followed by the mice's brain collection and histological and biochemical analyses. We also assessed whether pharmacological activation of AMPKα1 could serve as a therapeutic strategy to limit neuroinflammation and neurological damage after TBI. TBI significantly reduced AMPK phosphorylation in WT mice, while AMPKα1 deficiency in KO mice exacerbated behavioral deficits and increased NLRP3 inflammasome activation, leading to elevated levels of pro-inflammatory mediators, including caspase-1 and interleukin-1β. Notably, restoration of AMPKα1 phosphorylation via administration of a small-molecule activator A-769662 post-TBI significantly improved neurobehavioral outcomes. These improvements were accompanied by reduced blood–brain barrier disruption, lessened neutrophil infiltration, and decreased inflammasome activation compared with untreated TBI mice. Collectively, these findings suggest that pharmacological modulation of AMPKα1 signaling may represent a promising therapeutic approach to limit neuroinflammation, reduce secondary brain injury, and improve neurobehavioral outcomes after TBI.
Keywords: TBI, AMPK, Inflammasome, Neuroinflammation, A-769662, Neurobehavioral outcomes.
Phenotypes and Clustering Patterns of Infiltrating B Cells after Contusive Traumatic Brain Injury in Mice
1University Of Kentucky Spinal Cord and Brain Injury Research Center, Lexington, United States, 2University of Kentucky Department of Physiology, Lexington, United States, 3University of Kentucky Departments of Neurology and Neuroscience, Lexington, United States, 4University of Kentucky Department of Engineering, Lexington, United States
Traumatic brain injury (TBI) survivors often face persistent cognitive and neurobehavioral deficits. Despite advances in understanding the roles of astrocytes, microglia, and monocyte-derived macrophages involved in secondary injury cascades, the adaptive immune response to TBI, particularly that of B cells, remains understudied. We previously demonstrated region-specific B cell diapedesis into parenchyma of mice following a lateral controlled cortical impact (CCI). Interestingly, atypical B cell clusters were observed 14 days after injury, suggesting B cells may adopt pathogenic phenotypes. To evaluate antibody production that could result in autoimmunity, coronal brain sections from 5 CCI-injured mice were immunostained with B cell markers B220 and IgG. Some B220+ clusters contained IgG+ cells, occasionally colocalized, indicating that some B cells are producing antibodies at or near the clusters. To test the hypothesis that contusion TBI triggers the development of pathogenic B cell immunophenotypes within the cortex, adult male mice received a lateral CCI or sham injury (n = 6/group/timepoint). At 7 or 14 days after CCI or sham injury, 6 mm diameter cortical punches were collected and processed for flow cytometry. Preliminary analysis suggests elevated numbers of antibody-producing plasmablasts (CD45+B220-CD138+) at 7 and 14 days after CCI. The number of B regulatory cells (CD45+B220+CD5+) within the cortex also increased following CCI, indicating a subset of B cells may confer protection. Future analysis of splenic tissue and blood will provide insight into potential differentiation and migration patterns of B cells found within the cortex.
Phosphorylated Tau is Selectively Increased Around Brain Contusion
1Department of Laboratory Medicine and Pathology, University of Washington, Seattle, United States
Traumatic brain injury (TBI) is recognized as a risk factor for neurodegenerative disease, but the underlying mechanisms remain unclear. This study aimed to investigate how localized brain injury alters pathologic protein aggregation associated with neurodegenerative disease, focusing on hyperphosphorylated tau (p-tau) and beta-amyloid deposition in brain parenchyma adjacent to chronic contusion. Using brain donors from the University of Washington Brain Repository, cases with a diagnosis of unilateral chronic contusion were identified. Beta-amyloid and p-tau deposition were assessed in sections adjacent to the contusion and in contralateral sections without contusion (internal control). Manual counting and HALO imaging analysis were utilized to quantify the highest density of neuritic plaques/neurofibrillary tangles and deposition of abnormal protein in grey matter, respectively. In cases with neurofibrillary tangles, the %area of p-tau deposition and the density of neurofibrillary tangles were higher in contusion compared to the contralateral control. Whereas in cases with extracellular beta-amyloid plaques, there was no significant increase in plaque density with quantitative image analysis or counts of neuritic plaques performed by a neuropathologist. These findings support a selective relationship with p-tau and chronic traumatic brain injury.
Photobiomodulation Therapy Promotes Recovery of Cortical Functioning During Cognitive Performance in Patients with Mild Traumatic Brain Injury: A Feasibility Study
1University At Buffalo, Department of Pharmacology & Toxicology, Neuroscience Program, Jacobs School of Medicine & Biomedical Sciences, Buffalo, United States, 2University at Buffalo, Department of Neurology, Neuroscience Program, Jacobs School of Medicine & Biomedical Sciences, Buffalo, United States, 3University at Buffalo, Department of Oral Biology, Surgery & Biomedical Engineering, School of Dental Medicine, Buffalo, United States, 4University at Buffalo, Department of Periodontics, School of Dental Medicine, Buffalo, United States
Mild Traumatic Brain Injuries (mTBIs) can disrupt brain functioning during cognitive performance. Effective recovery of brain functioning following mTBI can help individuals return to normal activities, but treatment options remain limited in this population. Photobiomodulation (PBM) is a low-level laser therapy that can be applied to the head and is hypothesized to improve neural performance. In a randomized double-blinded feasibility study, we investigated if PBM treatment promotes recovery of brain functioning during cognitive performance following mTBI. Fifteen individuals with a recent mTBI were assigned to either a PBM treatment (n = 8) or sham/control group (n = 7) for six sessions over two weeks. Before and after the intervention, participants completed a computerized Go-NoGo task (testing target identification/response inhibition) while dense electroencephalogram (EEG) recordings were obtained. Event-Related Potentials (ERPs) were derived from the EEG, and the Local Autoregressive Average (LAURA) was applied to estimate cortical activity during task performance. Analyses of variance revealed a significant time (pre, post) X group (PBM, placebo) interaction for bilateral occipital cortex activity during the N1 ERP component time window for Go trials (left occipital: p = 0.045, ηp2= 0.294; right occipital: p = 0.051, ƞp2= 0.282). This interaction was explained by a reduction in occipital activity in the PBM group, in contrast to an increase in occipital activity in the placebo group from pre- to post-treatment. The findings provide preliminary evidence that PBM therapy promoted more efficient occipital activity during visual target detection compared to placebo, potentially reflecting a PBM-induced return to pre-injury functioning.
Phrenic Afferent Activity After C2 Hemisection and Diaphragm Pacing
1Department of Physical Therapy, Marquette University, Milwaukee, United States, 2Neuroscience PhD Program, Marquette University, Milwaukee, United States, 3Department of Physiology, Medical College of Wisconsin, Milwaukee, United States
The phrenic nerve innervates the diaphragm and is composed of motor (efferent) and sensory (afferent) axons. We have shown that delivering electrical stimulation known as diaphragm pacing (DP) to the hemidiaphragm ipsilateral to C2 hemisection (C2Hx) induces long-lasting plasticity and improves breathing in freely behaving male rats 24hrs post-DP. Since our data show that activation of phrenic afferents is necessary for these beneficial effects, we explored the impact of DP on phrenic afferent activity. We established a rodent model to record phrenic afferent activity and tested the hypotheses that: 1) phrenic afferent activity would be increased after chronic C2Hx and, 2) DP would alter the discharge pattern. To test these hypotheses, we recorded phrenic afferent output from the left whole phrenic nerve in anesthetized, spontaneously breathing adult Sprague-Dawley rats after chronic C2Hx (n=5), laminectomy (n=3), and naïve rats (n=4). We collected baseline phrenic afferent output, delivered intermittent DP (40Hz, 0.8mA) and recorded output for 60 minutes. Overall, phrenic afferent output shows a phasic inspiratory component and tonic discharge during expiration. Our preliminary data show a small main effect of group (p = 0.05), with phrenic afferent amplitude in C2Hx rats showing a slight elevation. DP did not alter phrenic afferent amplitude (p = 0.4) or discharge pattern. In conclusion, our data show that phrenic afferent output shows a phasic and tonic bursting pattern after C2Hx that is unaltered by DP. Understanding how phrenic afferent activity is altered by injury and clinically relevant treatments represents important step in developing these treatments.
Phrenic Proprioceptor Activation Induces Plasticity and Is Associated With c-Fos Activation Within the Phrenic Motor Nucleus
1Department of Physical Therapy, Marquette University, Milwaukee, United States, 2Neuroscience PhD Program, Marquette University, Milwaukee, United States, 3Exercise and Rehabilitation Science PhD Program, Marquette University, Milwaukee, United States
Approaches such as electrical stimulation of the phrenic neuromuscular system are currently used to manage breathing impairments following spinal cord injury (SCI). We recently showed that after SCI, phrenic afferent activation induces a long-lasting increase in diaphragm motor output and that daily stimulation significantly improves ventilation for at least 24hrs after stimulation in freely behaving animals. Understanding the mechanisms by which phrenic afferent activation induces plasticity is necessary to guide and improve the development of novel therapies. Here, we tested the hypotheses that intermittent phrenic afferent activation: 1) activates parvalbumin positive proprioceptors, and 2) engages the spinal neural network. To investigate this, spinal intact male rats received unilateral phrenic nerve stimulation (5, 5-minute episodes of 40 Hz, 160 µA, 0.1 ms pulse width) during inspiration (n=3), expiration (n=3), or served as time controls (n=3) not receiving stimulation. Sixty minutes after stimulation, the cervical spinal cord and DRGs (C3–C5) were collected, sectioned, and RNAscope was used to assess the activity marker c Fos and the proprioceptor marker parvalbumin. Our analysis indicates an increase in dual labeled parvalbumin/c-Fos positive cells in DRGs ipsilateral to stimulation compared to time controls (p = 0.035). In addition, our preliminary data shows that animals receiving inspiratory triggered stimulation showed a greater number of c-Fos positive cells (17.8%) compared to time controls. We conclude that activation of proprioceptive phrenic afferents triggers activity-dependent activation of spinal networks. This work highlights the potential of phrenic afferent stimulation as a strategy to activate the spinal network to improve breathing.
Physiology-Guided Programming of Epidural Spinal Cord Stimulation for Functional Restoration After Chronic Spinal Cord Injury
1HHRI, Minneapolis, United States, 2University of Minnesota, Minneapolis, United States
Epidural spinal cord stimulation (eSCS) has emerged as a promising neuromodulatory therapy capable of restoring elements of motor and autonomic function after chronic spinal cord injury (SCI). However, clinical outcomes depend on stimulation programming, which requires navigating a large parameter space of electrode configurations and stimulation parameters. Despite increasing clinical use, systematic workflows for individualized optimization remain poorly defined.
Objective: To characterize stimulation-evoked muscle recruitment patterns and present a practical workflow for individualized programming of epidural spinal cord stimulation in individuals with chronic thoracic SCI.
Methods: Participants with chronic motor-complete SCI implanted with 16-contact epidural paddle leads underwent systematic mapping of stimulation-evoked muscle responses using surface electromyography as part of the Epidural Stimulation After Neurologic Damage (ESTAND) trial. Bipolar stimulation patterns spanning horizontal, vertical, and diagonal electrode configurations were tested while stimulation frequency and pulse width were held constant. These observations were then incorporated into a structured clinical workflow for individualized parameter optimization.
Results: Stimulation-evoked responses demonstrated reproducible spatial features of muscle recruitment. Horizontal, vertical, and diagonal electrode configurations were tested to produce variable muscle activation relative to cathode position, enabling steering of motor output. Substantial inter-participant variability highlighted the need for patient-specific optimization. Based on these findings, we developed a structured programming workflow incorporating stimulation-evoked mapping to guide individualized parameter adjustment.
Conclusions: Physiologically informed mapping of stimulation-evoked muscle responses provides a practical framework for individualized programming of epidural spinal cord stimulation after SCI and may accelerate translation of neuromodulation therapies aimed at restoring motor and autonomic function.
Poor Local Feedback Sensitivity Drives Decision-Making Impairments After Frontal TBI in Rats
1The Ohio State University, Columbus, United States
Annually, over 2.8 million people are affected by traumatic brain injury (TBI) in the United States. Impairments in decision-making following frontal TBI are common but the mechanism underlying this is not well understood. We previously showed that frontal TBI reduced sensitivity to outcomes in rats. In the current study, we used two operant behavioral tasks to dissociate the contributions of global and local sensitivity to outcomes after frontal TBI.
Long-Evans rats were behaviorally trained before moderate-severe bilateral frontal control cortical impact (or sham control) for two separate studies (N=56, ½ TBI, ½ Female).
A Diminishing Returns Task evaluated global sensitivities. Rats were presented two choices, one of which the reward magnitude “depletes” over consecutive choices, and another that “resets” the first option. The point of reset measures optimization and global sensitivity to reward. TBI rats performed at sham levels, suggesting global sensitivity to outcomes remained intact.
In a separate study, a 3-choice Probabilistic Reversal Learning task evaluated local sensitivity. Rats were presented three choices (location randomized daily), each with a distinct probability of reward which then reversed mid-session. The time to switch preference to new contingencies measures local sensitivity to outcomes. The ability to adapt to abrupt change was impaired following TBI. Histological analysis is underway to further explore the brain regions implicated in this. Our findings indicate that local sensitivity to outcomes, rather than global sensitivity, is selectively impaired in decision-making following frontal TBI.
Post-TBI Sensitivity of the Auditory and Vestibular Systems to Intense Noise Exposure
1University Of Miami, Coral Gables, United States
Auditory and vestibular symptoms including hearing difficulty, dizziness, and balance disturbances are frequently reported after traumatic brain injury (TBI) but remain under-studied. Mechanisms underlying these deficits vary with injury severity. Moderate to severe TBI causes conductive loss associated with temporal bone fractures and may also involve sensorineural components. In contrast, mild TBI (mTBI) more commonly leads to sensorineural dysfunction resulting from injury to cochlear and vestibular hair cells and their neural pathways. The CDC reports that individuals at elevated risk for mTBI are also frequently exposed to hazardous noise, a well-established cause of inner-ear injury. In these populations, head and acoustic trauma may produce sequential rather than isolated sensorineural insults. We investigated auditory and vestibular outcomes in adult male Brown Norway rats (n=4/group) following mTBI, noise trauma, or sequential mTBI+noise injury. Diffuse mTBI was induced using the Marmarou weight-drop model. Separate cohorts were exposed to high-intensity noise alone or four days after mTBI. Longitudinal physiological testing targeted peripheral inner-ear function and was complemented by behavioral assessments of locomotion and cognitive performance. Compared with the mTBI- and noise-only groups, the double-insult model showed frequency-dependent changes in sensory recovery. Differences emerged primarily where noise-induced damage was less severe, whereas at frequencies associated with greater peripheral injury additive effects were limited, suggesting acoustic trauma largely determined sensory outcome. Behavioral assessments revealed locomotor alterations in the double-insult group, indicating impaired temporal coordination of gait. Spatial learning remained preserved, although animals adopted alternative navigation strategies consistent with compensatory adaptations to disrupted vestibular or sensorimotor input.
Power Spectral Density-Derived EEG Markers of Thalamocortical Integrity and Epileptogenic Risk Following Acute Hemorrhagic Traumatic Brain Injury
1University Of Pennsylvania, Philadelphia, United States, 2University of North Texas, Dallas, United States, 3University of California Los Angeles, Los Angeles,
Late post-traumatic seizures (PTS), occurring more than one week after traumatic brain injury (TBI), represent a serious complication. Currently there are no clinically validated EEG biomarkers of late PTS development. We hypothesize that preservation of theta relative power (4-8 Hz) that is associated with thalamocortical circuit integrity, would be protective against posttraumatic epileptogenesis.
Continuous EEG recordings obtained in the acute phase following TBI were analyzed in 71 patients enrolled in the multicenter EpiBioS4Rx study (n=34 developed late PTS, n=37 did not develop late PTS within 2 years after TBI). Power spectral density (PSD) was computed across standard frequency bands, and both absolute and relative bandpower features were extracted along with theta/delta ratio (TDR). Univariate group comparisons (Wilcoxon rank-sum), and logistic regression analyses were performed.
Theta relative power was significantly reduced in patients who developed late seizures compared to those who did not (p = 0.019; 95% CI: 0.537-0.799). The TDR was likewise lower in patients who developed late PTS and independently predicted late seizures in logistic regression (p = 0.022, 95% CI: 0.001-0.369).
EEG theta relative power and the TDR in the acute TBI phase may serve as non-invasive markers of thalamocortical circuit integrity following TBI, with preserved theta activity reflecting cortical inhibition and reduced late seizure susceptibility. These findings support the hypothesis that thalamocortical dysfunction, represented by delta dominance and theta suppression, may play an important role in the processes underlying post-traumatic epileptogenesis.
Precision Prevention of Post-traumatic Epilepsy: A Metabolomics-Driven Machine Learning Framework Unlocks Early Predictive Biomarkers
Dr. Xiang Mao1
1Department of Neurosurgery, TBI, The First Affiliated Hospital of Anhui Medical University, Hefei, China
Introduction: Post-traumatic epilepsy (PTE) remains a devastating consequence of traumatic brain injury (TBI), affecting 15–20% of survivors and lacking reliable biomarkers for early risk stratification. Current clinical predictors, such as injury severity and early seizures, exhibit poor sensitivity and specificity. Previous evidence suggests metabolic dysregulation and neuroinflammatory pathways contribute to epileptogenesis. This study integrates untargeted metabolomics with machine learning to identify plasma biomarkers and construct predictive models for PTE risk in TBI patients.
Materials and Methods: A prospective cohort of 467 adult TBI patients (Glasgow Coma Scale≤14) was recruited at a Level I trauma center. Blood samples were collected within 72 hours post-injury and longitudinally at 1, 3, and 6 months. Patients were followed for 24 months to assess PTE development (defined per ILAE criteria). Untargeted metabolomics profiling was performed using liquid chromatography-mass spectrometry (LC-MS) in positive/negative ion modes. Differential metabolites were identified via orthogonal partial least squares-discriminant analysis (OPLS-DA) and pathway enrichment analysis (KEGG). A random forest (RF) algorithm was optimized for feature selection, and predictive models were validated using 10-fold cross-validation and an independent cohort (n=196).
Results: Comprehensive metabolomic profiling revealed distinct metabolic signatures between PTE converters (n=91) and non-converters (n=376). At 72 hours post-injury, 12 metabolites (VIP>1.5, p<0.001) were significantly dysregulated, including elevated lysophosphatidy -lcholines (LysoPC(18:0), LysoPC(20:4)) and decreased sphingosine-1-phosphate (S1P). Longitudinal analysis showed progressive accumulation of neurotoxic ceramides (Cer(d18:1/24:0)) and depletion of neuroprotective docosahexaenoic acid (DHA). Machine learning identified a 7-metabolite signature (AUC=0.92, 95% CI: 0.88–0.96) comprising LysoPC(18:0), S1P, and DHA, outperforming clinical variables alone (AUC=0.78). Pathway analysis implicated dysregulated sphingolipid metabolism and arachidonic acid pathways in PTE pathogenesis.
Conclusions: This study establishes a metabolomic fingerprint for PTE risk, integrating phospholipid remodeling and neuroinflammatory dysregulation. The validated 7-metabolite signature demonstrates superior predictive accuracy, offering a novel tool for early identification of high-risk TBI patients. These findings align with the mission to advance precision medicine in PTE prevention and highlight the therapeutic potential of targeting sphingolipid pathways. Future multi-centers validation and mechanistic studies are warranted to translate these biomarkers into clinical practice.
Predictors of Patient Satisfaction with Emergency Department Care Following Traumatic Brain Injury: A Survey-Based Study
1Medical College of Wisconsin, Milwaukee, United States, 2University of Kentucky, Lexington, United States, 3The Ohio State University, Columbus, United States, 4Brain Care Catalyst Foundation, Milwaukee, United States
As the primary point of entry for the traumatic brain injury (TBI) care continuum, the emergency department (ED) plays a critical role in accurate diagnosis and immediate intervention. This central role necessitates a closer look at the factors that predict patient satisfaction with the care received during these high-stakes encounters. We conducted a prospective survey of 1,514 adults treated for TBI or head injury across seven EDs within a single health system in Southeastern Wisconsin between September 25, 2024, and May 27, 2025. Facilities included one academic level 1 trauma center, one level 3 trauma center, one level 4 trauma center, and four freestanding (non-trauma-rated) EDs. Satisfaction with ED care, the primary outcome, was measured using a 5-point Likert-type scale and dichotomized (Very Satisfied or Not Very Satisfied) for binary logistic regression modeling. Older age (OR = 1.16, 95% CI= 1.03–1.31), male sex (OR = 2.03, 95% CI = 1.22–3.39), having a support person involved during discharge (OR = 2.34, 95% CI= 1.41–3.89), and receiving recommendations from the care team on activities to avoid (OR= 2.99, 95% CI = 1.80–4.98) were associated with higher odds of being very satisfied with TBI care received in the ED in the multivariable model. Our study contributes to the limited literature on patient experience and satisfaction with ED-based TBI care. These findings can inform efforts to strengthen patient-centered care practices and guide system-level improvements across EDs.
Prefrontal Cortex Injury Drives Neuroinflammation in the Nucleus Accumbens while Microglial Turnover Worsens Injury-driven Impulsivity
1The Ohio State University, Columbus, United States
Chronic impulsivity is common after traumatic brain injury (TBI), yet the circuit-level mechanisms remain unclear. Persistent neuroinflammation may drive maladaptive remodeling within corticostriatal networks, particularly the nucleus accumbens (NAc), a key hub for impulse control, decision-making, and reward processing. Because microglia regulate post-injury inflammation and synaptic plasticity, we tested whether aberrant microglial responses contribute to NAc circuit dysfunction and chronic behavioral impairment after TBI.
Adult male and female Long-Evans rats received a moderate-to-severe focal prefrontal cortex controlled cortical impact. First, we evaluated glial profiles at a subacute 14-day post-injury timepoint using single-nucleus RNA sequencing. In a separate cohort, to test the role of microglia, we pharmacologically depleted microglia from days 7–21 post-injury and allowed repopulation. Impulsive behaviors were assessed during repopulation, and single-cell sequencing characterized repopulated microglia 7 days later.
TBI increased the proportion of sequenced microglia in the NAc and upregulated neuroinflammatory and activation pathways. Behaviorally, TBI increased impulsivity, reduced motivation and accuracy in the five-choice serial reaction time task, and increased time spent in the open arms of the Elevated Plus Maze. Microglial turnover exacerbated impulsivity, impaired accuracy, and worsened spatial learning in the Morris Water Maze compared to TBI controls. Repopulated microglia displayed altered activation and inflammatory transcriptional profiles.
Moderate focal prefrontal TBI induced persistent neuroinflammatory and neuroplastic changes within the NAc associated with impaired executive function. These findings suggest persistent microglial responses in distal regions such as the NAc may be protective by compensating for ongoing circuit remodeling.
Funding source: the Department of Defense (HT9425-23-1-1003).
Pregnancy Specific Glycoprotein 1 (PSG1) Overexpression Primes Homeostatic Restoration and Modulates Sex-Specific Microglial Activation Following Traumatic Brain Injury
1Henry M. Jackson Foundation, Department of Anatomy, Physiology, and Genetics, Uniformed Services University School of Medicine, Bethesda, United States, 2School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, United States, 3University of Minnesota School of Dentistry, Malcolm Moos Health Sciences Tower, Minneapolis, United States, 4Department of Pathology, Uniformed Services University School of Medicine, Bethesda, United States, 5Department of Anatomy, Physiology, and Genetics, Uniformed Services University School of Medicine, Bethesda, United States
Traumatic brain injury (TBI) initiates a complex neuroimmunological cascade characterized by the transition of resident microglia from homeostatic to reactive phenotypes following injury. This study investigates how overexpression of (PSG1), a naturally occurring immunomodulatory protein produced by the placenta, influences microglial dynamics and phenotypic skewing in a sex-specific manner following head trauma.
Adult male and female C57BL/6J (WT) and PSG1-KI mice underwent Controlled Cortical Impact (CCI), Closed Head Injury (CHI), and Sham procedures. At 2 and 7 days post-injury (DPI), cortical tissues were processed using a 10-antibody flow cytometry panel to isolate brain-resident microglia. Micropunches were also taken from the injury epicenter for bulk RNA-sequencing.
At 2 DPI, flow cytometric and transcriptomic analyses revealed robust, model-specific activation. Through flow cytometry, the WT microglia remained largely sequestered in a homeostatic state, yet the PSG1 mice exhibited a higher frequency of microglia transitioning into an activated state. This activation followed distinct sex-specific patterns: PSG1 males displayed a dense cluster characterized by high co-expression of CD86 and CD274, whereas PSG1 females exhibited a smear pattern. Through DEG data analysis, PSG1 mice exhibited an upregulation of microglial activation and immunomodulatory markers, most notably Cd274, Cd44, and Cd200, compared to WT controls.
Our data suggests that PSG1 acts as a molecular brake to neuroinflammation and may protect the brain from chronic secondary injury in a sex-specific manner. These findings identify PSG1 as a critical regulator that could accelerate the resolution of microglial activation and promote the return to a homeostatic phenotype following head trauma.
Pregnancy Specific Glycoprotein 1 (PSG1) Overexpression Skews Peripheral Immune Cells Towards Anti-Inflammatory Subpopulations Following Traumatic Brain Injury
1Henry M. Jackson Foundation, Department of Anatomy, Physiology and Genetics, Uniformed Services University School of Medicine, Bethesda, United States, 2School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, United States, 3University of Minnesota School of Dentistry, Malcolm Moos Health Sciences Tower, Minneapolis, United States, 4Department of Pathology, Uniformed Services University School of Medicine, Bethesda, United States, 5Department of Anatomy, Physiology and Genetics, Uniformed Services University School of Medicine, Bethesda, United States
Peripheral immune cells (PICs) infiltrate the brain within minutes following a Traumatic Brain Injury (TBI). PICs adopt a spectrum of pro- to anti-inflammatory cell states to influence TBI outcomes; molecular interventions targeting PIC phenotypes are a focus of TBI research. PSG1 is a member of an immunoglobulin superfamily secreted by the placenta and a known modulator of innate immune cells. To determine the role of PSG1, C57BL/6J (WT) and PSG1-knockin male and female mice underwent Controlled Cortical Impact (CCI) or Closed Head Injury (CHI) surgeries. At 2 and 7 days post-injury (DPI), PICs were isolated and analyzed via flow cytometry using a diagnostic 10-antibody panel. At 2DPI, CCI male and female PSG1 mice exhibited a greater shift towards immunosuppressive neutrophils over inflammatory neutrophils when compared to WT mice who received CCIs. When examining these neutrophils in the CHI model, this shift towards the immunosuppressive phenotype is seen in the male PSG1 mice compared to their WT counterpart. There is also a decrease in the percentage of pro-inflammatory macrophages for the PSG1 mice in both injury models and sexes when compared to WT mice at 2DPI. Additionally, these male CCI PSG1 mice have a marked increase in the anti-inflammatory macrophage population compared to the male WT mice that received CCIs. These data indicate that PSG1 plays a role in skewing the PIC populations towards more anti-inflammatory phenotypes in the acute post-injury period. By modulating these systemic immune cells, PSG1 represents a potential therapeutic agent for limiting secondary injury-induced neuroinflammation.
Pre-Injury Sleep Quality Alters Alcohol Consumption and Functional Outcomes Following TBI
1Department Of Integrative Physiology, University Of Colorado Boulder, Boulder, USA, 2Civilian Institution Programs, Air Force Institude of Technology (AFIT/CI), Wright-Patterson AFB, USA, 3Veteran Affairs Rocky Mountain Mental Illness Research, Education, adn Clinical Center (MIRECC) for Suicide Prevention, Aurora, USA, 4University fo Colroado, Anschutz Medical Campus, Department of Physical Medicine and Rehabilitation, Aurora, USA, 5Veteran Affairs Brain Health Coordinating Center, Aurora, USA, 6University of Colorado, Anschutz Medical Campus, Departments of PM&R, Psychiatry, and Neurology, Aurora, USA, 7Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, USA, 8Wu Tsai Neurosciences Institute, Stanford University School of Medicine, Stanford, USA
Traumatic brain injury (TBI) predicts later alcohol misuse, which impedes rehabilitation and worsens long-term outcomes. While both sleep disorders and TBI increase vulnerability to substance abuse, whether pre-injury sleep disruption alters post-TBI alcohol consumption and recovery remains unknown. We hypothesized that sleep disruption prior to TBI primes microglia-mediated inflammation, thereby altering post-injury alcohol consumption and behavioral outcomes.
Adult male and female mice (n=90) were exposed to sleep disruption (SD) or undisturbed sleep for 4 weeks prior to diffuse TBI or sham surgery. After a 7-day recovery period, voluntary alcohol consumption was measured using a two-bottle choice paradigm (water vs. 20% ethanol) for 4 weeks. Behavioral outcomes were then assessed using rotarod, neurological severity score (NSS), open field (OF), and novel object recognition (NOR).
Females consumed more fluids overall than males (p < 0.0001). Importantly, TBI increased alcohol intake in females (p < 0.05) and sleep disruption altered intake patterns in males (p = 0.032).
Following alcohol consumption (5-weeks post-injury), TBI impaired rotarod performance (p = 0.0018), whereas SD increased neurological impairment measured by NSS (p = 0.047). No TBI or SD effects were observed in OF or NOR performance, although females traveled farther in OF and showed greater investigation time in NOR.
These findings demonstrate that sleep disruption prior to TBI alters alcohol consumption and recovery following the injury in a sex-dependent manner. Ongoing analyses are quantifying microglial morphology using morphometric histology and inflammatory cytokines using multiplex assays to determine whether sleep disruption primes neuroimmune responses underlying these behavioral changes.
Progressive Network Reorganization After Traumatic Brain Injury: From Focal Disruptions to Global Network Inefficiency
1Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States, 2Department of Neurosurgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States, 3Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, United States
Objective: Resting-state fMRI studies in TBI often examine networks individually, leaving unclear how communication across large-scale brain systems evolves after injury. We compared network organization between TBI patients and controls at 2 weeks and 6 months post-injury to determine whether early abnormalities resolve or propagate across the connectome over time.
Methods: TRACK-TBI Resting-state fMRI data were analyzed at 2 weeks (409 TBI, GCS 13-15; 62 controls) and 6 months (348 TBI; 60 controls) post-injury. Functional connectivity was summarized using graph-theoretic metrics capturing integration (nodal efficiency), local specialization (clustering coefficient), and hubness (betweenness centrality). Metrics were averaged within 7 Yeo networks: default mode (DMN), frontoparietal (FPN), dorsal attention (DAN), salience/ventral attention (SN/VAN), sensorimotor (SMN), limbic (LIM), and visual (VIS). Age- and sex-adjusted linear models tested patient–control differences.
Results: At 2 weeks, patients showed reduced efficiency in attention and control networks, FPN (d=-0.41) and DAN (d=-0.29), alongside increased DMN betweenness centrality (d=0.18). By 6 months, disruptions were more widespread and larger in magnitude. Reduced efficiency was observed across six networks (SN/VAN, FPN, DAN, LIM, VIS, and SMN; d=-0.30 to -0.53), with largest decline in networks already abnormal at 2 weeks. DMN, clustering decreased (d=-0.30), while elevated betweenness persisted (d=0.20) (FDR-corrected p<0.05).
Conclusion: Network abnormalities did not normalize but intensified and expanded across systems over time. Early disruption in attention networks was followed by widespread reductions in network efficiency, while persistently elevated DMN hubness with widespread network inefficiency suggests redistribution of communication as system-wide disruption progresses, indicating progressive connectome reorganization following TBI.
Protein Panels and Pathways Related to Persisting Post-Concussion Symptom Domains in Adolescents
1Johns Hopkins University School of Nursing, Baltimore, United States, 2Department of Neurology, University of Utah, Salt Lake City, United States, 3Department of Neurology, University of California, Los Angeles, United States, 4Department of Pediatrics, Department of Epidemiology, University of Washington and Seattle Children's Research Institute, Seattle, United States, 5Division of Pediatric Neuropsychology, Children's National Hospital, Rockville, United States, 6Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, United States, 7Utah Data Coordinating Center, University of Utah, Salt Lake City, United States, 8Division of Neurology, Departments of Pediatrics and Neurosurgery, UCLA School of Medicine, University of California Los Angeles, Los Angeles, United States, 9Emergency Medicine and Neurology, University of Rochester Medical Center, Rochester, United States, 10Johns Hopkins University School of Medicine, Baltimore, United States
Introduction: Concussion symptoms are heterogeneous and span multiple domains: cognitive, physical, emotional, and sleep/fatigue. While many acute concussion symptoms resolve within weeks, symptoms persisting longer than three months after injury are defined as persisting post-concussion symptoms (PPCS) and show little spontaneous recovery. To identify potential biomarker panels predictive of PPCS, we examined overlapping proteins and pathways across the four symptom domains.
Methods: This longitudinal analysis used a subset of data from the Concussion Assessment, Research, and Education for Kids (CARE4Kids) study. Adolescents presenting 7–35 days after injury were recruited from outpatient settings. Symptom severity was assessed using the Retrospective Adjusted Post-Injury Difference-Post-Concussion Symptom Inventory-2 (RAPID-PCSI2). Participants in the upper and lower 25% of RAPID-PCSI2 scores for each symptom domain at 3 months post-injury were compared using Olink Explore HT proteomic profiling to 5,400 plasma proteins collected at study entry.
Results: Of 236 participants (age mean ± SD: 15±1.8; 55% females), for each domain, 69–73 participants were in the high-symptom groups, and 106–149 in the low-symptom groups. Thirty-two proteins were significantly dysregulated (p<0.05) across all four domains, including Leptin, Apolipoprotein E, Persephin, and Wnt Inhibitory Factor 1 (WIF1). Receiver operating characteristic models demonstrated good prognostic performance for the 32-protein panel across domains (AUCs>0.83). Pathway analysis indicated up-regulated neutrophil degranulation and down-regulated integrin cell surface interaction in high-symptom groups for all domains.
Implications: Proteomic analysis revealed shared protein signatures associated with PPCS. The overlapping 32-protein panel showed promising predictive performance. Future research should refine biomarker profiles to better characterize PPCS in adolescents.
Psychoplastogens Unlock the Chronic Injured Brain for Effective Cognitive Rehabilitation in Rats
1Veteran Affairs, Phoenix, United States, 2University of Michigan, Physical Medicine and Rehabilitation, Ann Arbor, United States, 3University of Michigan Concussion Center, Ann Arbor, United States, 4University of Michigan, Neuroscience Graduate Program, Ann Arbor, United States, 5University of Arizona College of Medicine-Phoenix, Phoenix, United States
Diffuse traumatic brain injury (TBI) leads to axonal injury, synaptic deafferentation, vascular permeability, and neuroinflammation that collectively disconnect neural circuits. Coincident maladative regenerative responses reorganize circuits, establishing persistent cognitive impairment as a common clinical outcome. We developed the Peg Forest, a rodent cognitive rehabilitation task, that prevents the onset of TBI-induced cognitive impairments when initiated subacutely post-injury. However, when rehabilitation was prescribed after cognitive impairments developed in the chronic TBI phase, Peg Forest rehabilitation was ineffective to rescue cognitive function. Therefore, we hypothesized that psychoplastogen administration in the chronic TBI phase could induce a neuroplastic state such that the combination with Peg Forest rehabilitation would recover cognitive function. To test this, male and female Sprague-Dawley rats all received midline fluid percussion injury. We confirmed injury-induced cognitive impairment 1-month post-injury using three tasks: novel object recognition, novel object location, temporal order object recognition. Cognitive rehabilitation included a single high dose of ketamine (20mg/kg, IP) or saline 1 day prior to 10 days of Peg Forest rehabilitation (15min/day) over 2 weeks or remaining in the home cage. Cognitive function was reassessed the week following rehabilitation. Saline with rehabilitation and ketamine without rehabilitation were ineffective in altering cognitive performance within animals. When ketamine preceded Peg Forest rehabilitation, cognitive function was significantly improved compared to within-animal pre-rehabilitation object recognition tasks and compared to the control groups. Thus, psychedelic medicine mediated effective cognitive rehabilitation, likely through enhanced neuroplasticity in relevant cognitive circuits in the chronic phase after TBI.
Putting a Damper on TBI: Identifying Injury-Derived Progressive Transcriptional Regulation Occurring within Midbrain Inhibitory GABAergic Neuron Populations
1University of Cincinnati, James L. Winkle College of Pharmacy, Division of Pharmaceutical Sciences, Cincinnati, United States, 2University of Cincinnati, College of Medicine, Neuroscience Graduate Program, Cincinnati, United States
Traumatic brain injury (TBI) is a major public health concern. Approximately 80% of clinical TBI’s are mild (mTBI), 25% of which result in enduring neurologic/neuropsychiatric deficits. Midbrain structures are hypothesized to be preferentially affected by acceleration-deceleration events, an inherent part of many TBI’s. GABAergic neurons are relatively understudied in the context of TBI and are prevalent within the midbrain. We hypothesize that acceleration-deceleration-elicited mTBI results in alterations of midbrain GABAergic neuron populations, impacting the physiologic excitatory/inhibitory balance stemming from midbrain GABAergic neurons. To test this hypothesis, adult, C57Bl/6 subjects underwent mTBI or sham procedures using a multimodal blast- and acceleration-deceleration model for mTBI. Three, ten, or thirty days post-injury (dpi), midbrain samples were excised and underwent nuclei isolation and single nuclei RNA sequencing procedures. Using Seurat to analyze data, GABAergic neurons were identified based on positive expression of Gad1 and/or Gad2, in combination with NeuN (Rbfox3) expression. Analysis revealed 1312 differentially expressed genes (DEGs), 3956 DEGs, and 1679 DEGs, 3, 10 and 30-dpi, respectively (adjusted P value ≤ 0.05). STRING analysis of top 500 DEGs within GABAergic neuron populations, revealed significant alterations in pathways associated with cell adhesion and glutamate receptor activity 3 dpi, glutamatergic synapses 10 dpi and transmembrane transporter activity 30 dpi. Studies herein provide evidence of acute and protracted impacts of a single acceleration-deceleration injury on GABAergic neurons of the midbrain with a high level of temporal resolution, effects that may be associated with alterations in the excitatory-inhibitory balance of the brain post-injury.
Real-Time In Vivo Imaging Reveals Early Perilesional Neurovascular Failure and Therapeutic Rescue by Membrane-Sealing Nanoparticles after SCI
Dr. Wei Wu1
1University of Louisville, Louisville, United States
Vascular disruption is an early and critical event in spinal cord injury (SCI), yet the spatiotemporal dynamics of blood-spinal barrier (BSCB) failure beyond the injury epicenter and its causal contribution to secondary degeneration remain unclear. Using novel in vivo two-photon dual-dye imaging, we found simultaneous blood-spinal cord barrier (BSCB) leakage and venous dilation in both the injury epicenter and adjacent transitional segment after cervical SCI in rats. Notably, vascular permeability in the transitional zone preceded axonal and neuronal loss, revealing a therapeutic window. Systemic delivery of ferulic acid-glycol chitosan (FA-GC) nanoparticles, a membrane-sealant, rapidly stabilized the compromised vasculature, reduced neuronal loss in the transitional region, and improved forelimb muscle strength. These findings identified acute vascular leakage beyond the injury epicenter as a driver of secondary pathology and highlight early vascular stabilization as promising therapeutic strategy.
Real-time Intraoperative Ultrasound and Postoperative MRI: Implications for Duraplasty in AIS grades A-C Traumatic Cervical SCI
Dr. Bizhan Aarabi1, Dr. Gary Schwartzbauer1, Dr. Kenneth Crandall1, Dr. Joshua Olexa1,
1University of Maryland, Department of Neurosurgery, Baltimore, United States
Objectives: Real-time intraoperative ultrasound (IOUS) is a promising modality in traumatic cervical spinal cord injury (tCSCI) for decompression verification (recent conditional recommendation). We questioned if quantitative IOUS can distinguish duraplasty patients from patients with adequate bone-only decompression using postoperative MRI.
Methods: One-hundred-and-eighteen consecutive AIS grades A-C tCSCI patients who underwent IOUS evaluation during posterior cervical surgery were included in this study. Postoperative MRI confirmed adequate decompression in all patients. The cross-sectional subarachnoid to subdural area fraction at the epicenter (S2AFE) was compared among laminectomy plus duraplasty (n=8) versus laminectomy-only (n=110).
Results: Mean age was 55.7 years. Admission AIS grades were A (n=47), B (n=27), and C (n=44). Mean ASIA motor score (AMS) was 16.7. Mean preoperative and postoperative intramedullary lesion length (IMLL) was 42.9 mm and 55.5 mm, respectively. Mean laminectomy bed length was 67.2 mm and mean number of laminectomy levels was 3.8. Mean S2AFE was 47.1%. Laminectomy only decompression was adequate in 110 patients (mean S2AFE 49.1%), and eight patients had laminectomy plus duraplasty (mean S2AFE 18.6%). Age, admission AMS, preoperative and postoperative IMLL, laminectomy bed length, number of laminectomy levels, and S2AFE were significantly associated with selection for duraplasty, with areas under ROC curve (AUC) 0.77, 0.78, 0.91, 0.94, 0.88, 0.92, and 0.99 respectively.
Conclusions: Seven percent of patients (AIS grade A only) had expansion duraplasty. The cross-sectional subarachnoid to subdural area fraction at the epicenter (S2AFE) alone had an AUC of 0.99 for duraplasty and occurred primarily in younger AIS grade A patients with higher IMLL.
Receptor-Interacting Protein Kinase 1/3-Mediated Inflammasome Activation Drives Chronic Blood-Brain Barrier Damage After Controlled Cortical Impact in Mice. drives chronic blood-brain barrier damage after controlled cortical impact in mice
1Massachusetts General Hospital, Boston, United States
Objective: Blood-brain barrier (BBB) damage occurs in the chronic period of traumatic brain injury (TBI) through unknown mechanisms. We hypothesized that a receptor interacting protein kinase-1 (RIPK1)-inflammasome signaling axis cell autonomously drives chronic BBB damage in a mouse controlled cortical impact (CCI) model.
Methods: 2-month-old male and female mice were subjected to CCI. BBB damage was assessed by 70kDa FITC-dextrans, vasculogenesis by 2mDa FITC-dextrans, and activation of RIPK1, RIPK3, and inflammasome proteins in isolated brain endothelial cells by western blot. Data were analyzed by ANOVA/t-test.
Results: CCI induced striatal vasculogenesis and BBB damage between 1 and 2 weeks that persisted through 2 months in male > female mice (p < 0.05). At 2 months after CCI, striatal endothelium in males (but not females) showed activated RIPK1 and RIPK3, and caspase-1 and interleukin-1β processing that was sensitive to caspase-1/11 knockout and RIPK1 and RIPK3 inhibition. Male (but not female) mice lacking caspase-1/11, or functional RIPK1 or RIPK3, had significantly (p < 0.01) reduced BBB damage vs. WT, but similar striatal vasculogenesis, at 2 months. Inducible genetic inhibition of endothelial IL-1 receptor-1, or administration of caspase-1 inhibitor VX765, or the FDA-approved RIPK1 inhibitor Primidone, at several weeks after CCI reduced established BBB damage (p < 0.05).
Conclusions: The data identify a novel, sex dependent brain endothelial cell-autonomous RIPK1/3-inflammasome mechanism that drives chronic BBB damage after CCI independent of reparative angiogenesis. RIPK1, RIPK3, and inflammasomes are therapeutic targets to reduce established BBB damage in males during the chronic period of contusion TBI.
Refining Criteria to Minimize Recovery Variability in a Rat Severe Spinal Cord Injury Model
1VA Eastern Colorado Health Care System, Aurora, United States, 2North Florida/South Georgia Veterans Healthcare System, Gainesville, United States, 3University of Colorado School of Medicine, Aurora, United States
After spinal cord injury (SCI), locomotor recovery is associated with skeletal muscle recovery. The rat severe contusion SCI model mimics the pathophysiology of severe SCI in humans and does not typically recover hindlimb stepping. However, a small subset of severe contusion SCI rats exhibit spontaneous locomotor recovery that adds considerable variability to group outcomes. Our objectives were to 1) compare soleus muscle mass in rats that received severe SCI and did not recover hindlimb stepping (non-walkers, NW) versus rats that recovered walking by 3-weeks post-SCI (early walkers, EW) and 2) explore potential quantitative criteria to identify SCI rats likely to become EW. We examined Infinite Horizons impactor force and velocity, Basso-Beattie-Bresnahan (BBB) locomotor scores, bodyweight change, and soleus masses from an existing cohort of (N=130) 4-mo-old littermate-matched male Sprague-Dawley rats. Rats received severe T9 contusion SCI (programmed at 250 kilodynes; range: 249–380 kilodynes) and were followed for 3-weeks. Of these, 18% (N=23) were classified as EW (≥8.5 BBB score within 3-weeks). Soleus mass (corrected for laminectomy-only sham soleus mass) was 39% higher in EW versus NW (p=0.001). Regression analyses revealed the measured impactor force (p=0.020) and 1-week BBB scores (p<0.001) influenced EW predictions, while other variables did not achieve statistical significance but improved model fit. The regression model with the best fit (R2=0.478) correctly classified 88.4% of EW and NW. Once validated, criteria identified by regression may predict EW rats after severe contusion SCI, which could reduce variability in muscle and locomotor outcomes when implemented before group assignment.
Rehabilitation Differentially Restores Reaching Kinematics Across Cervical Spinal Cord Injury Models
1Marquette University, Milwaukee, United States, 2University of Miami, Miami, United States, 3Brain and Spinal Injury Center (BASIC), Dept. of Neurological Surgery, University of California, San Francisco, San Francisco, United States, 4San Francisco VA Healthcare System, San Francisco, United States
Background: Cervical spinal cord injury disrupts descending motor control. Targeted activity-based therapy is a clinically ubiquitous rehabilitative intervention whose efficacy covaries with specific injury features. Relationships between injury features, motor deficits, and recovery capacity remain poorly understood. To capture the breadth of motor phenotypes seen clinically, we characterized movement-level kinematics of skilled forelimb motility across deliberately varied injury types.
Methods: Mice (n=16/cohort; final n=9-14) received pyramidotomy, contusion, or cervical hemisection injuries and were assessed at baseline, post-injury, and following voluntary rehabilitative training using an automated Farr-Whishaw skilled pellet retrieval task. We analyzed and scored sessions using DeepLabCut and custom reach-parsing algorithms. Feature selection and linear mixed models were used to identify predictors of retrieval and track recovery across groups.
Results: Pellet attention and contact differed significantly by injury group and time (linear mixed model, p<0.001, η2=0.24–0.41), with significant injury-by-time interactions across all outcomes (η2=0.51–0.55). Retrieval was similarly reduced across all injury groups (p=0.06, η2=0.10). LASSO identified swipe length, area, and speed as the strongest predictors of retrieval. All three showed significant group, time, and interaction effects (p<0.05), with post-injury declines followed by rehabilitation-associated rebounds that varied significantly by injury type (p<0.05, η2=0.30–0.46).
Conclusions: Mice with different injury types showed distinct kinematic recovery trajectories, indicating that injury location and severity constrain motor recovery capacity. Animals that regained baseline movement form without recovering original success rates demonstrated genuine motor recovery rather than compensatory strategy. We are currently linking kinematic profiles with supraspinal connectivity to identify circuits underlying recovery potential.
Reliability of Self-Reported Traumatic Brain Injury Over 25 Years
1University of Pennsylvania, Philadelphia, United States, 2University of Mississippi Medical Center, 3National Institute of Neurological Disorders and Stroke, 4New York University,
Objective: To assess the consistency of self-reported traumatic brain injury (TBI) over 25 years in community-dwelling older adults and to examine factors associated with inconsistent reporting.
Methods: The Atherosclerosis Risk in Communities Study (ARIC) is an ongoing cohort study of 15,792 community-dwelling adults from four U.S. locations. Starting at in-person visits in 1993-1995 followed by 5 in-person visits (1996-1998, 2011-2013, 2016-2017, 2018-2019, 2021-2022), questions about TBI history were asked. Frequencies and percent positive agreement were used to assess consistency in responses among individuals who had at least two visits with responses (yes or no) to the TBI questions. To investigate factors associated with inconsistent reporting, we used multivariate logistic regression.
Results: Overall, 11,862 participants responded at two or more visits to the TBI questions, of whom 1,972 participants responded ‘yes’ to TBI and had at least one follow-up response. Among the 11,862 participants with at least two documented responses, 9% were inconsistent (defined as saying ‘yes’ to TBI and ‘no’ at one or more subsequent visits). Among the 1,972 participants who responded ‘yes’ to a TBI, 56% responded ‘no’ at one or more subsequent visits. Female sex and lower education were associated with greater odds of inconsistent reporting; cognitive status was not associated with inconsistency in reporting.
Conclusion: Self-reported TBI history is largely consistent when including individuals who never report a TBI. However, there is greater inconsistency when looking among the subset of individuals who report a TBI, where female sex and lower education were associated with inconsistent reporting.
Reorganization of Intrinsic Neural Oscillations Underlies Symptom Recovery After Traumatic Brain Injury: Evidence from Neurodynamic Modeling of the TRACK-TBI Cohort
Can Liao1, Sujin Jiang1, Dr. Yingjian Liu1, Dr. Xianqiao Wang1,
1University of Georgia, ATHENS, United States
Many TBI patients fail to recover to pre-injury status within six months, yet the mechanisms underlying divergent outcomes remain poorly understood. Blood-based biomarkers and behavioral assessments lack the biological specificity to explain persistent symptoms or recovery variability, motivating the use of neuroimaging, including diffusion MRI (dMRI) and functional MRI (fMRI), to identify specific abnormalities. Here, we investigated brain recovery after TBI using neuroimaging and neurodynamic models linking structural networks to neural synchronization, hypothesizing that recovery emerges from reorganization of intrinsic neural oscillations rather than structural rewiring alone. We analyzed longitudinal data from 468 individuals in the TRACK-TBI dataset with imaging at two weeks and six months post-injury. Structural connectivity (SC) was derived from dMRI tractography and functional connectivity (FC) from resting-state fMRI. FC at both timepoints was simulated using a Kuramoto oscillator model, with SC defining interregional coupling and regional intrinsic frequencies optimized to minimize deviations from empirical FC. Individuals were stratified into four outcome groups based on longitudinal RPQ scores. Changes in regional intrinsic frequency showed significant differences (FWER-corrected p < 0.05) between recovered and other groups. Differences were observed between recovered and deteriorated cases in one Visual and one Dorsal Attention region, and between recovered and partially recovered cases in one Limbic, four Default Mode, and one Frontoparietal regions. In contrast, changes in SC, synchrony, and metastability did not differ across outcome groups. These findings suggest that reorganization of intrinsic neural oscillations plays a key role in functional recovery after TBI and highlight potential targets for neuromodulatory interventions.
Repeat Mild TBI Causes Social Avoidance and Memory Deficits in Peromyscus californicus
1University Of California, Davis, Davis, United States, 2Veterans Association of Northern California Health Care System, Sacramento, United States
It is well-documented that in both the civilian and military population that repeat mild traumatic brain injury (rmTBI) often coincides with significant stress. California mice are monogamous, and both males and females are highly aggressive. When placed in a common environment, one animal will dominate an encounter, with defeated mice demonstrating prolonged stress-like behaviors making this a unique model for studying social stress. To test the hypothesis that California mice are a unique model for studying the intersection of stress and rmTBI, female California mice (n=8) were given 5x closed skull rmTBI every other day over 9 days using controlled cortical impact followed by chronic behavioral testing starting 9 weeks post-injury. Shams received similar durations of anesthesia but were not impacted (n=8). Preliminary data demonstrate that rmTBI mice spent less time (47.8±10.1 seconds) interacting with an unfamiliar stimulus mouse (p<0.05) as compared to shams (91.3±11.7 seconds), suggesting a social deficit. Furthermore, while 100% of sham mice preferred the novel object (p<0.05; Wilcoxon Signed Rank), rmTBI animals performed at chance. These data show that injured California mice exhibit multiple persistent stress- and cognitive-behavioral deficits and have the potential to be a useful model to examine the effects of combined social stress and rmTBI.
Repeat Traumatic Brain Injury and Alzheimer’s Disease: Shared Calcium Dysregulation and Downstream Consequences in Mouse Models
1Rosalind Franklin University of Medicine and Science, North Chicago, United States, 2Chicago Medical School, RFUMS, North Chicago, United States
Repeat traumatic brain injury (rTBI) is a risk factor for Alzheimer’s disease (AD). rTBI and AD share comorbidities including impaired bioenergetics, synaptic signaling, and memory deficits. Despite overlapping symptomatology, mechanisms driving increased neurodegenerative risk after injury are understudied. We hypothesize that repeat injury initiates chronic neuronal calcium (Ca2+) dysregulation promoting an AD-cellular pathogenic phenotype. Non-transgenic (NonTg) mice and triple transgenic AD (3xTg-AD) mice received three mild closed-head TBI or SHAM injuries, 48 hours apart. 30 days post-final injury, mice were euthanized and brains extracted for 2-photon Ca2+ imaging, whole-cell patch clamp and field potential electrophysiological recordings, single cell RNA sequencing, and mitochondrial isolation to determine downstream consequences of Ca2+ dysregulation on cellular and network activity. Our data show that rTBI induces intracellular Ca2+ handling deficits resulting in chronic synaptic and bioenergetic pathology mirroring AD. 3xTg-AD SHAM mice display increased ryanodine receptor (RyR)-evoked Ca2+ release as compared to NonTg rSHAM (***p<0.001), which is found in the NonTg rTBI group (***p<0.001). 3xTg-AD rSHAM animals show increased frequency of spontaneous excitatory post synaptic currents as compared to NonTg rSHAM, which is recapitulated by the NonTg rTBI group (**p<0.01). Single cell RNA sequencing data displayed chronic downregulation of mitochondrial genes including Complex I, III, and V subunits in rTBI animals. Isolated mitochondria from NonTg rTBI animals showed decreased cytochrome c-dependent electron transport activity as compared to NonTg rSHAM (*p<0.05). Taken together, rTBI promotes key pathogenic features seen in AD, including chronic Ca2+ dysregulation, synaptic, and metabolic deficits, bridging the gap between injury and neurodegeneration.
Repeated Traumatic Brain Injuries Cause More Edema Than Single Injuries in “Middle-Aged” C57BL/6J Mice
1University Of California, Riverside, Riverside, United States, 2Indiana University School of Medicine, Indianapolis, United States, 3Stark Neuroscience Research Institute, Indianapolis, United States
Objective: Emerging reports show that concussions may accelerate the risk of Alzheimer’s disease (AD) and related dementias (ADRD). Single and repeated concussions can lead to poor cognition and affective disabilities long-term. We aimed to characterize acute vascular and neural perturbations in “mid-life” adult (8mo) mice exposed to a single (sCHI) or repeated closed head injury (rCHI).
Methods: 8-month-old adult male and female mice (C57BL/6J) underwent a sCHI over the left somatosensory cortex. In the rCHI group, a second concussion was delivered 3days later, but to the ipsilateral frontal cortex. One day after the last injury, mice were perfusion-fixed using our vessel painting paradigm, then underwent ex vivo T2-weighted (T2WI), and Susceptibility-Weighted Imaging (SWI, blood) MRI. Brains were further characterized for evaluation of BBB disruption and cerebrovascular perturbations.
Results: Neither weight gain, righting time, nor time to explore differed between the two groups of injured mice and their respective sham controls. Whole brain volumes did not change significantly across groups. T2-relaxation was not different between sCHI and shams, but significantly increased in the 3d-rCHI group. Intriguingly, T2 values were often lower in the ipsilateral somatosensory cortex compared to the uninjured contralateral hemisphere. SWI indicated ∼30% bleeding in sCHI mice, and ∼7% in rCHIs.
Conclusions: We demonstrate that a rCHI at 8-months of age increases brain edema relative to sCHI, and vascular perturbations may contribute to tissue-level changes visible on MRI. This study is the first step towards assessing how repeated concussions and associated vascular alterations may result in progressive ADRD symptomology.
Repetitive Head Impact Exposure is Associated with a Distinct Pattern of White Matter Hyperintensities among Athletes in Early Adulthood
1Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, United States, 2Department of Neurology, Columbia University, New York, United States, 3Department of Neurology, Boston University Chobanian & Avedisian School of Medicine, Boston, Boston, United States, 4Department of Clinical and Health Psychology, University of Florida, Gainsville, United States, 5Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Department of Neurology, Columbia University, New York, United States, 6Boston University Alzheimer’s Disease Research Center, Boston, United States, 71Florida Alzheimer’s Disease Center, Gainsville, United States
Background: Repetitive head impact (RHI) exposure is associated with a distinct pattern of white matter hyperintensities (WMH) characterized by small, punctate, non-confluent, spherical lesions proximal to deep gray matter (RHI-WMH). These lesions were observed previously in middle-aged to older former tackle football players. RHI-WMH have not been assessed earlier in the lifespan. This study examined the frequency of RHI-WMH and associations with RHI in young-adult football players.
Methods: Current male football players (N=56; Mage=21.1±1.5) completed interviews to characterize RHI history and received 3D T2-weighted FLAIR MRI, which were analyzed with an in-house developed pipeline to characterize RHI-WMH ≤ 1.0 cm from the gray-white matter boundary. RHI metrics included years of all contact sport participation and the Cumulative Head Impact Index (CHII). Logistic regression models were fit to test associations between RHI proxies and the binary presence/absence RHI-WMH.
Results: RHI-WMH were recorded in 31% of the sample. Fourteen percent exhibited two or more lesions. A trend toward greater odds of RHI-WMH lesion presence was observed among those with greater years of contact sport participation (OR=1.12; 95%CI=.98-1.27, p=.09). Those with RHI-WMH had a mean of 2.5 more years contact sport exposure. Odds of RHI-WMH were greater with higher CHII values, though this was not statistically significant (OR=1.0002, 95%CI=.9999-1.0006, p=.21).
Conclusions: The distinct pattern of RHI-WMH is present as early as young-adulthood, though the burden/count is lower compared to prior reports in older adults. Total contact sport exposure was associated with RHI-WMH presence, as well as to a lesser degree, a football-only metric.
Repetitive Head Impacts Drive Collagen IV Vascular Remodeling Before Tau Pathology in Chronic Traumatic Encephalopathy
1Department of Anatomy and Neurobiology, Boston University Chobanian and Avedisian School of Medicine, Boston, United States, 2 Boston University Alzheimer’s Disease and CTE Centers, Boston, United States, 3Section of Computational Biomedicine, Department of Medicine, Boston University Chobanian and Avedisian School of Medicine, Boston, United States, 4VA Boston Healthcare System, Boston, United States, 5Department of Neurology, Boston University Chobanian and Avedisian School of Medicine, Boston, United States, 6Department of Pathology and Laboratory Medicine, Boston University Chobanian and Avedisian School of Medicine, Boston, United States
CTE is a neurodegenerative disease found in individuals with a history of repetitive head impacts (RHI). Currently, CTE can only be diagnosed postmortem with the identification of neuronal hyperphosphorylated tau (pTau) around blood vessels at the depths of cortical sulci. Given this association, there is evidence of an important relationship between disease pathogenesis and the vascular system. To further investigate these changes, we used single-nucleus RNA sequencing (snRNAseq) and immunofluorescence (IF) from human postmortem dorsolateral frontal cortex (DLFC) samples to characterize vascular remodeling in response to RHI. Four groups of cases (aged 22-59) were compared: non-RHI controls, individuals with RHI but no CTE, individuals with low stage CTE, and high stage CTE. First, snRNAseq revealed an enriched cluster of capillary cells unique to individuals with RHI exposure. Analyses of this cluster demonstrated higher expression of collagen-associated genes, including COL4A1/COL4A2. Next, multiplex IF further demonstrated that collagen IV (ColIV) was elevated in response to RHI. Interestingly, while a ColIV increase was observed in the sulcal vasculature of cases with RHI, individuals with low CTE had reduced ColIV compared to RHI only and high CTE cases. Finally, to determine if ColIV changes also correlate with vessel function and stiffness, elastin levels were analyzed. Overall, findings indicated that RHI drives cerebral vascular remodeling prior to, and potentially contributing to, CTE pathogenesis. However, changes did not progress linearly, possibly suggesting different temporal dynamics of vessel dysfunction, which will be critical to consider when developing and implementing diagnostic and therapeutic strategies for CTE.
Retrospective Application of the 2023 American Congress of Rehabilitation Medicine’s Diagnostic Criteria for Mild Traumatic Brain Injury
1Medical College of Wisconsin, Milwaukee, United States
The 2023 American Congress of Rehabilitation Medicine diagnostic criteria for mild traumatic brain injury (mTBI) replace the long-used 1993 definition, necessitating studies into their clinical application. We retrospectively applied the 2023 criteria to individuals prospectively enrolled in a study aimed at improving acute TBI classification. The sample was N=219 adults (Mage=41.4; 50.7% female, 48.1% Caucasian) enrolled in level I trauma centers within 24 hours of a TBI with Glasgow Coma Scale (GCS) scores of 13-15. The ACRM criteria were coded from the electronic health record (EHR; ED triage nurse and provider notes) and research assessments performed in-hospital <24 hours of injury (e.g., structured diagnostic interview data, computerized reaction time performance), allowing for comparisons of diagnostic information across sources. Using all available data, the percentage of participants within ACRM diagnostic categories was as follows: 94.0% mTBI, 4.6% Suspected mTBI, 1.4% no mTBI. Among those who were CT- (n=181), 89.5% qualified for ACRM-defined mTBI through Criterion 2 (Clinical Signs) and 3.3% qualified through Criteria 3 and 4 (Acute Symptoms + Clinical Examination & Laboratory Findings). Notably, ACRM-defined mTBI diagnoses based solely on the EHR were uncommon: 25.4% mTBI, 9.4% Suspected mTBI, 65.2% no mTBI. In contrast, research assessments alone identified 91.2% mTBI, 6.1% Suspected mTBI, and 2.8% no mTBI. Agreement between these data sources was minimal (26%; Cohen’s k=.006), largely accounted for by missing documentation of criteria in the EHR. Findings support the application of the 2023 ACRM criteria when comprehensive data are available, while highlighting limitations in routine ED documentation.
Risk of Spinal Canal Neoplasm after Traumatic Spinal Cord Injury: A Propensity-Matched Cohort and Case-Control Study
1University of Louisville, Louisville, United States
Objective: We examined whether traumatic spinal cord injury (SCI) is associated with subsequent spinal canal neoplasm (SCN) in a large international cohort.
Methods:We performed a retrospective cohort study and a complementary case control analysis using de identified electronic health records from the TriNetX Global Collaborative Network. For the cohort analysis, we identified patients with incident SCI with adequate follow-up. The primary outcome was incident SCN, defined as intramedullary or intradural extramedullary neoplasms. Propensity score matching (PSM) was performed 1:1.
Results:
Retrospective Cohort
After PSM, the retrospective cohort included 132,080 matched pairs. The risk of spinal canal neoplasm was significantly higher in the spinal cord injury group compared with controls (Hazard Ratio, 6.92; 95% CI, 3.80-11.55). Kaplan-Meier analysis demonstrated a divergence in the cumulative probability of neoplasm early in the follow-up period, which persisted through 108 months of observation.
Case-control
After PSM, the case-control analysis included 22,210 matched pairs. The prevalence of SCI was significantly higher in the neoplasm cohort (1.671%) than in the control cohort (0.265%), yielding an adjusted odds ratio of 6.38 (95% CI, 4.84–8.40; P < .001). The absolute risk increase (ARI) for a history of SCI in patients with SCN was 1.41% in the matched cohort.
Conclusion: Traumatic spinal cord injury was associated with significantly increased risk of subsequent spinal canal neoplasm. These findings support spinal cord injury as a potential risk factor for spinal canal neoplasm and warrant further investigation into long-term outcomes.
Role of Neuronal CCR5 in Spinal Cord Injury
1Medical College of Wisconsin, Milwaukee, United States, 2Clement J Zablocki Veterans Affairs Medical Center, Milwaukee, United States
Spinal cord injury (SCI) is a devastating condition that causes severe neurological deficits, determined by the level and extent of tissue damage. The initial mechanical insult causes primary tissue damage and is exacerbated by secondary damage mechanisms, including inflammation. Early inflammation has tissue protective properties while prolonged inflammation can be detrimental to functional recovery.
Chemokines are signaling molecules which mediate immune cell migration and activation.
Chemokines and their receptors are known to upregulate on immune cells following SCI and have been identified as mediators of tissue damage and inflammation. Previous literature reports that neuronal C-C chemokine receptor 5 (CCR5) expression is linked to neuronal death in neurodegenerative diseases. We have previously shown that global pharmacological inhibition of CCR5 resulted in improved functional recovery and better tissue preservation following SCI. We therefore hypothesize that neurons express and upregulate CCR5 after SCI, resulting in impaired neuron survival and functional recovery.
We assessed our own single nuclear (sn) and publicly available single cell (sc) RNAseq datasets after SCI to determine chemokine receptor expression on neurons. CCR5 is expressed by neurons in uninjured and injured spinal cord tissues, with upregulation occurring after SCI. Notably, ligands are also upregulated following SCI, primarily on immune cells. Using RNAscope, we confirmed differential expression levels of CCR5 in neurons and detected CCR5 predominantly expressed in excitatory glutamatergic neurons. Using in vitro and in vivo approaches, we aim to delineate the mechanism of neuronal CCR5 activation and the impact of neuron-specific CCR5 deletion on function recovery after SCI.
Rugby Head Impact Exposure Predicts Microstructural Alterations in the Superior Longitudinal Fasciculus
1Department of Bioengineering, Stanford University, Stanford, United States, 2Department of Radiology, Stanford University, Stanford, United States, 3Stanford Center for Clinical Research, Stanford University, Stanford, United States, 4Department of Neurosurgery, Duke University, Durham, United States
Head impact exposure is associated with white matter microstructural changes, yet tract-specific dose–response relationships remain unclear. We examined whether cumulative exposure predicts tract-specific MR diffusion changes and whether simulated strain improves prediction over sensor-derived impact kinematics.
Twenty-one collegiate rugby athletes and 19 low-contact controls underwent pre- and post-season multi-shell diffusion MRI quantifying fractional anisotropy (FA) and isotropic volume fraction (FISO) in the superior longitudinal fasciculus (SLF), corticospinal tract (CST), and corpus callosum (CC). Head impacts were recorded via instrumented mouthguards and simulated using a finite element (FE) brain model.
Group differences were observed in SLF FA (p=0.015), CST FA (p=0.013), and SLF FISO (p=0.004), but not the CC. Mixed-effects regression was then conducted in SLF and CST . Cumulative impact count was associated only with SLF FISO changes (β=0.0002, p<0.001). FE simulations revealed peak strains concentrated in the periphery supratentorially, including the subcortical white matter overlapping the SLF.
White matter strain (MPS95WM) and peak linear acceleration (PLA) were statistically modeled separately and in combination as predictors of microstructural changes. PLA (p<0.0001) and the combined model (p<0.0001) predicted SLF FISO changes, with the combined model showing improved fit over PLA alone (BIC: -166 vs. -155).
These findings suggest a relationship between SLF free water (FISO) increases and impacts in college rugby athletes. MPS95WM alone was not predictive of microstructural changes, indicating regional FE metrics may not independently capture microstructural injury, and that tract-specific strains may be required. However, the combined model improved fit, suggesting that strain provides complementary information beyond kinematics.
Safety and Utility of Increased Spatial Sampling with Low-Profile Cylindrical Electrodes for Intracranial Electrophysiology in Severe Brain Injury
1Department of Neurological Surgery, University of California San Francisco, San Francisco, United States, 2Department of Neurology, University of California San Francisco, San Francisco, United States
Intracranial electroencephalography (iEEG) after severe brain injury has shown promise in detecting seizures and spreading depolarizations (SDs), which are associated with poor outcome. However, spatial coverage has been sparse, typically using six to eight electrodes, risking the under-detection of clinically significant signals.
To extend the degree of spatial sampling, and explore the utility of low-profile cylindrical electrodes, patients undergoing cranial surgery for severe brain injury were implanted with cylindrical iEEG electrodes at the time of craniotomy (n=1) or craniectomy (n=6). One patient received a 12-contact cylindrical electrode. The remaining six received both a standard 8-contact iEEG strip and a cylindrical electrode (8 contacts, (n=3); 16 contacts (n=2); 12 contact (n=1)).
When compared with strip electrodes, cylindrical iEEG signals showed normal physiologic activity, SDs, and spikes. The use of multiple electrodes showed broader spatial detail than single strip electrodes, and 2/7 patients had SDs that were concordant between electrodes. In one case burst suppression was seen on a cylindrical electrode that would have been missed on the strip alone. Importantly, no complications or morbidity were associated with cylindrical electrode monitoring, demonstrating the safety of this approach.
This study demonstrates that cylindrical electrodes can be safely placed on the brain cortical surface to produce high-quality iEEG data similar to strip electrodes. The use of multiple electrodes captured additional spatial features that may otherwise be missed. These results pave the way for further studies in the spatial topography of electrophysiologic abnormalities after severe brain injury for enhanced diagnostic and potentially therapeutic applications.
Schwann Cell Growth Properties in Collagen Mesh Implant for Cauda Equina Repair
1Norton College of Medicine, Upstate Medical University, Syracuse, United States, 2Department of Neurosurgery, Upstate Medical University, Syracuse, United States, 3Department of Cell and Developmental Biology, Upstate Medical University, Syracuse, United States
Schwann cell transplantation has shown promise in enhancing nerve repair in both the peripheral and central nervous systems. After a nerve injury, Schwann cells adopt a repair phenotype, secreting factors which stimulate axonal growth. Given this, Schwann cells have been included in nerve grafts or guidance channels to promote repair after spinal cord or peripheral nerve injury. In our work, we have designed an implantable collagen mesh seeded with Schwann cells to treat damaged nerve roots in the cauda equina. The Schwann cells utilized are autologous, isolated from a small nerve segment, and expanded in culture before implantation.
Previous studies were often conducted in rodent injury models; however, rodent Schwann cells may have different growth properties than human cells. We are utilizing a porcine model of cauda equina injury to test the repair capabilities of the Schwann cell seeded collagen mesh. However, the characteristics of porcine Schwann cells are not well described, especially after injury. Here we evaluated Schwann cells from several species seeded on collagen. We examined cell proliferation, migration, and the appearance of a repair phenotype over time, which significantly influences their ability to stimulate axon regrowth. Rodent, canine, and porcine Schwann cells were cultured on a 3D collagen mesh and visualized by confocal microscopy. Concurrently, Schwann cells were grown on coverslips and immunostained to identify their phenotype. All species expressed markers of both the repair and myelinating phenotype. More importantly, the Schwann cells survived on and embedded into the 3D collagen mesh, showing promise for neurosurgical applications.
Selective Alteration of Astrocytes in Post-Traumatic Epilepsy
1Department of Laboratory Medicine and Pathology, University of Washington, Seattle, United States, 2Department of Acute Brain and Cardiovascular Injury, Mario Negri Institute for Pharmacological Research, Milan, Italy
Traumatic brain injury (TBI) is a risk factor for the development of epilepsy, though the cellular and network mechanisms underlying the development of post-traumatic epilepsy (PTE) are not well understood. The orbitofrontal cortex (OFC) and thalamus are vulnerable regions to injury after traumatic brain injury, and the thalamus, in particular, is known for its role in seizure propagation. Therefore, we investigated if neuroinflammation might differ in these two regions in brain donors with and without PTE and chronic TBI compared to controls. Postmortem human tissue analyses of TBI PTE+ patients and TBI PTE- patients demonstrated increased astrocytic reactivity in the thalamus and OFC in the PTE+ group but not the PTE- compared controls. Microglial reactivity was identified in both TBI groups only in the OFC. Astrocytes also demonstrated reduced cytoskeletal branching complexity in the PTE+ group in the OFC and the thalamus compared to controls. Parallel studies in a mouse model of PTE recapitulated these results and of most interest, these changes in astrocytes occurred in high-risk mice before seizure onset, supporting a causal relationship of astrocytes with epileptogenesis. These findings identify astrocytic pathology, especially in the thalamus, as a clinically relevant hallmark of PTE conserved across species, and a possible target for intervention. Further research is needed to understand how this astrogliosis might modify neural circuits to initiate and spread hyperexcitable activity associated with epilepsy.
Serum Biomarker Diagnostic and Prognostic Efficacy in Human Degenerative Cervical Myelopathy Patients
1University Of Kentucky, Department of Physiology, Lexington, United States, 2Spinal Cord and Brain Injury Research Center, Lexington, United States, 3University of Kentucky, Department of Neurosurgery, Lexington, United States
Degenerative Cervical Myelopathy (DCM) is the leading cause of non-traumatic spinal cord injury (SCI). Despite its prevalence, diagnoses are often delayed due to the lack of DCM-specific symptoms. In addition to self-reported outcomes (e.g., the modified Japanese Orthopedic Association (mJOA) score) as well as functional and sensory declines, an MRI is necessary for a definitive diagnosis of DCM to show evidence of spinal cord compression and myelomalacia. Currently, decompression surgery is the only disease-modifying therapeutic intervention with long-term symptom relief. However, the factors that predict successful decompression surgery are not well understood. In both pre-clinical and clinical research, there is evidence of altered inflammatory responses as DCM progresses and in response to decompression surgery. In addition, evidence supports the presence of ischemia due to constricted blood flow and reperfusion after decompression surgery. However, diagnostic tools to assess disease severity and prognostic tools for surgical success are lacking. Our goal is to identify blood biomarkers to assess disease severity and that correlate with pre-surgery mJOA scores. To achieve this goal, we are conducting a longitudinal study collecting plasma from DCM patients pre-surgery (currently, n=72) and at 6 months (n=61) and 12 months (n=43) post-surgery for array-based protein analysis of 39 biomarkers using the V-Plex Human Biomarker Assay from MesoScale Discovery). N=7 subjects with peripheral nerve damage and a surgical intervention serve as a control group. From this study, we aim to identify groups of biomarkers that may serve as a diagnostic or prognostic tool for DCM patients.
Serum P-tau-181 and Injury Severity in Spinal Cord Injury: The Confounding Effect of Post-Traumatic Time
1China Rehabilitation Research Center, Beijing, China, 2School of Rehabilitation Medicine, Capital Medical University, Beijing, 中国
Background: Phosphorylated tau at threonine 181 (P-tau-181) has been identified as a promising biomarker for central nervous system injuries. However, its association with spinal cord injury (SCI) severity remains uncertain, potentially due to changes in biomarker expression over time following trauma.
Objective: To determine whether serum P-tau-181 levels can distinguish SCI severity (AIS A+B vs. C+D) and to evaluate the confounding impact of post-traumatic time on this relationship.
Methods: This retrospective study included 24 SCI patients (AIS A+B: n=10; AIS C+D: n=14) treated at the China Rehabilitation Research Center. Serum P-tau-181 levels were quantified using immunoassay. Group comparisons were performed using the Mann–Whitney U test. Spearman and partial correlation analyses were conducted to assess relationships among P-tau-181, injury severity, and post-traumatic time.
Results: Median serum P-tau-181 levels were significantly higher in the AIS A+B group than in the AIS C+D group (83.49 vs. 44.43 pg/mL; U=114.0, p=0.011). Post-traumatic time differed significantly between groups (35 vs. 137 days; U=17.5, p=0.002) and showed a strong negative correlation with P-tau-181 (ρ=-0.678, p<0.001). After adjusting for post-traumatic time, the correlation between injury severity and P-tau-181 disappeared (partial ρ=-0.008, p=0.988).
Conclusions: P-tau-181 is not an independent indicator of SCI severity when post-traumatic time is uncontrolled. Time since injury must be considered a key confounding factor in future biomarker studies.
Keywords: P-tau-181; spinal cord injury; biomarker; AIS grade; post-traumatic time; confounding factor
Severe High-Thoracic Spinal Cord Injury Disrupts Acute Autonomic Function: Cardiovascular, Temperature, and Activity Implications
1University of Kentucky, Lexington, United States, 2Novoron Bioscience, San Diego, United States, 3University of Louisville, Louisville, United States, 4Northwestern University, Evanston, United States
Spinal cord injury (SCI) disrupts supraspinal influence on autonomic function, leading to alterations in cardiovascular parameters such as blood pressure, heart rate, temperature, and activity. The understanding of autonomic physiology, especially cardiovascular changes in animal models acutely after injury, is important to develop targeted interventions that prevent disease progression into long-term disability. To our knowledge, the acute effects of severe, high-thoracic (T3), contusion SCI on these autonomic parameters remain understudied and have not been systematically characterized. In the present study, we analyzed the effect of SCI on systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and heart rate (HR) in female rats. Adult female rats were implanted with in vivo telemetric implants in the descending aorta. Two weeks after implant surgery, animals received T3 spinal contusion (400 kdyn, 5s dwell time). We collected baseline telemetry for SBP, DBP, HR, temperature, and activity for 48 hours prior to SCI and then continuous recordings from 1 to 7 dpi. There was increased in blood pressure (SBP, DBP, and MAP) starting from 1 to 4 dpi. There was drastic disruption of diurnal rhythms especially for heart rate, temperature, and activity. SCI also led to severe heart rate irregularities, temperature fluctuations, and a decrease in activity. Overall, this work provides new insight into acute autonomic changes after SCI. Determining whether these early autonomic changes predict long-term cardiovascular and functional deficits will better define therapeutic windows and guide future development of interventions to improve chronic SCI outcomes.
Sex- and Stress-Dependent Relationships with NOP Receptor Modulation on Cerebral Blood Flow and Neurotrophin Signaling After Traumatic Brain Injury
1Department of Pharmaceutical Sciences, The University of Oklahoma College of Pharmacy, OU Health Campus, Oklahoma City, United States, 2Department of Cell Biology, The University of Oklahoma College of Medicine, OU Health Campus, Oklahoma City, United States
Traumatic brain injury (TBI) and posttraumatic stress (PTSD) are commonly co-morbid, with limited effective treatments. We previously reported that TBI increased brain nociceptin/orphanin FQ (N/OFQ) and its receptor, NOP expression. We tested whether co-morbid PTSD and topical NOP modulators altered TBI-induced changes in cerebral blood flow (CBF). Adult male and female rats (N=5-8/group) received craniectomy (Cr-sham) or controlled cortical impact TBI ± single prolonged stress (SPS) exposure as the PTSD model. Cortical CBF was measured using laser speckle imaging (LSCI) over 3 hours post-Cr/TBI, +/- topical NOP modulator application and tissue collected. TBI reduced ipsilateral CBF in both sexes (p<0.01), independent of PTSD. Ipsilateral N/OFQ increased in both female SPS groups (p<0.05), but not in males, NOP antagonist (SB-612111) improved CBF in stressed females and all Cr-Sham rats, while NOP partial agonist (AT-035) worsened CBF in stressed females (p=0.005), but not males.
Three hours post-TBI, neuronal loss (NeuN intensity) was sex-dependent with males exhibiting greater loss after TBI alone than females. Microglial activation (Sholl analysis) increased with each trauma; most activation in female polytrauma. Injury markers assessed included pro- and mature BDNF, its receptor p75NTR, and MMP-9 (secreted by activated microglia, cleaving proBDNF to mature-BDNF). Both trauma types increased MMP-9 in males, but only TBI increased it in females. Both BDNF forms decreased in females exposed to SPS and to SPS+TBI (p<0.05); levels were unchanged in males. p75NTR increased in male TBI groups but increased in females only with TBI+Cr.
Sex- and trauma-dependent N/OFQ and neurotrophin signaling modulate CBF.
Sex Chromosomes as Novel Drivers of T-Cell Phenotypes and Locomotor Recovery After SCI
1Spinal Cord and Brain Injury Research Center and Department of Physiology, College of Medicine, University of Kentucky, LEXINGTON, United States, 2Spinal Cord and Brain Injury Research Center and Department of Neuroscience, College of Medicine, University of Kentucky, LEXINGTON, United States, 3Department of Pharmacology and Nutritional Sciences, Saha Aortic, University of Kentucky Center, University of Kentucky, LEXINGTON, United States, 4Department of Pediatrics, Division of Research University of Kentucky, LEXINGTON, United States
The inflammatory response to spinal cord injury (SCI) involves innate/adaptive immune mechanisms, including T-cell infiltration, and exhibits sex-specific differences. To distinguish the relative contributions of gonadal sex and sex chromosome complement, we used 3–4-month-old Four Core Genotypes (FCG) mice (XX or XY with either ovaries or testes) subjected to T9 contusion SCI. Splenic T-cells were analyzed at 7- and 42-days post-injury (dpi) for proliferation (CFSE) and lineage differentiation (CD4+, CD8+) following CD3/CD28 stimulation, alongside ex vivo subset quantification. Spinal cords at 7 dpi underwent single-cell RNA sequencing; datasets were integrated 10x Genomics-datasets processed using Harmony and analyzed in Loupe Browser. Locomotor recovery was assessed using the Basso-Mouse-Scale (BMS) weekly through 42 dpi.
Splenic T-cell proliferation did not differ among groups at 7 dpi but was significantly increased at 42 dpi in mice with ovaries, independent of chromosome complement. The Y chromosome did not influence proliferation. Ovaries promoted CD8+ lineage differentiation, and the Y chromosome transiently increased CD8+ cells at 7 dpi. Testes favored CD4+ differentiation, with higher splenic CD4+ proportions at 42 dpi. Single-cell analysis identified 30 spinal cord cell clusters, including a CD3e+ T-cell cluster enriched in mice with ovaries or an XX complement. Although differentially expressed genes were detected among nine T-cell subclusters, none reached significance under stringent criteria. Notably, the Y chromosome independently improved BMS subscores at 42 dpi.
Collectively, we observed that gonadal sex and chromosomes differentially regulate T-cell responses and functional recovery after SCI, identifying sex chromosomes as novel contributors to sexual dimorphism in SCI.
Sex Differences in Stress-Primed Responses to Blast-Induced Traumatic Brain Injury Reveal Distinct Molecular Injury Signatures
1Salem VAMC, Blacksburg, United States, 2Virginia Tech University, Blacksburg, United States
Chronic stress and allostatic overload can lead to detrimental changes in neural circuitry, cognition, and mood. Although the pathophysiological response to blast-induced neurotrauma (BINT) has traditionally been attributed to the blast itself, emerging evidence suggests that stress experienced prior to injury may “prime” the brain, producing molecular responses that could exacerbate injury outcomes. This priming effect may also differ between sexes, contributing to distinct pathophysiological signatures and long-term impairment. Therefore, it is important to consider stress as a pre-existing condition when developing clinically relevant models of BINT. This study aimed to identify molecular signatures that differentiate BINT injury responses in the context of pre-stress exposure and determine whether these responses differ across sexes. Male and female Sprague–Dawley rats were assigned to four groups: control (CON), stress only (AUS), TBI only (BINT), or stress + TBI (AUS+BINT). AUS consisted of three days of unpredictable stress, including restraint, predator urine exposure, and forced swim, while BINT involved one blast exposure per day for three days. Amygdala proteins were analyzed using mass spectrometry-based proteomics (MaxLFQ) to identify differentially expressed proteins (DEPs), followed by Ingenuity Pathway Analysis (IPA). In males, 696 significantly dysregulated proteins were identified in the AUS+BINT group (p < 0.05), compared with 308 in females. IPA identified 148 signaling pathways uniquely dysregulated in AUS+BINT males and 71 in females, with only seven shared between sexes. These findings demonstrate that prestress exposure produces distinct and sex-divergent molecular signatures following BINT, highlighting biological mechanisms that may inform future therapeutic strategies.
Sex-Differences in Microglial Neuronal Interaction after TBI
1University of Washington, Seattle, United States
Microglia are increasingly recognized to shape neuronal circuit function. Our recent work identified that perineuronal satellite microglia (Sat-MG) regulate neuronal intrinsic excitability. Here we further investigated how this relationship changes after traumatic brain injury (TBI) in both male and female mice and the role of P2Y12 receptors, a homeostatic microglial protein with reduced expression after TBI. Utilizing whole-cell patch clamp in transgenic mice with GFP-labeled microglia, we obtained recordings in neurons both with and without Sat-MG. In addition, we recorded from cells incubated in solution with and without a P2Y12R antagonist. We identified a differential response that was sex-dependent. Satellite microglia no longer regulated intrinsic excitability after TBI, but only in male mice. Similarly, the P2Y12R antagonist blocked the ability of Sat-MG to regulate neuronal activity in male mice, but this effect was not seen in female mice. Our results support sex-specific differential regulation of satellite microglia-neuronal interaction with prominent differences especially noted after TBI.
Sex-Specific Glial Remodeling and Sleep Fragmentation Disrupt Growth Hormone Signaling After Juvenile Traumatic Brain Injury
1University Of Colorado Boulder, Department of Integrative Physiology, Boulder, United States, 2University of Glasgow, Glasgow, Scotland, 3Stanford University School of Medicine, Palo Alto, United States, 4Cumberland Biological and Ecological Researchers, Logmont, United States
Traumatic brain injury (TBI) during juvenile development occurs during a critical window of neuroendocrine maturation, yet the mechanisms linking injury to endocrine dysfunction remain poorly understood. Growth hormone (GH), which is predominantly released during sleep, regulates brain development and plasticity. Importantly, glia express GH receptors capable of modulating local neuroendocrine signaling. We tested whether post-injury sleep disruption and glial remodeling following juvenile TBI are associated with dysregulation of the somatotropic axis.
Male and female peripubertal rats (postnatal day 35) underwent midline fluid-percussion injury (mFPI) or sham surgery (n = 56), and we continuously monitored sleep. At 7 days post-injury we measured circulating hormones and quantified glial responses using GFAP and IBA-1 immunohistochemistry with morphometric classification of microglial phenotypes across brain regions.
Males exhibited pronounced sleep fragmentation accompanied by reductions in circulating GH and IGF-1. In both sexes, astrocyte activation increased after injury, and hippocampal GFAP coverage negatively correlated with circulating GH levels (p = 0.036), suggesting astrocyte remodeling contributes to endocrine dysfunction after juvenile TBI. Microglial responses revealed sex-dependent patterns. Both sexes showed reductions in homeostatic ramified microglia following injury (males, p < 0.0001; females, p = 0.005), indicating activation of the neuroimmune response. In males, this remodeling localized to the hippocampus, where ramified microglia decreased significantly. In contrast, females exhibited a brain-wide shift characterized by increased ameboid microglia.
Together, these results reveal a glia–sleep–endocrine axis following juvenile TBI, where sex-specific microglial responses and astrocyte activation associate with disrupted GH signaling and endocrine dysfunction during developmental recovery.
Sex-Specific Neuroimmune Responses to TBI Following Inhibition of MIF/CD74 Signaling in Mice
1Texas A&M Institute for Neuroscience, Texas A&M University, College Station, United States, 2Department of Neuroscience & Experimental Therapeutics, Naresh K. Vashisht College of Medicine, Texas A&M University, Bryan, United States
Traumatic brain injury (TBI) is a major cause of mortality and disability worldwide. TBI is characterized by an acute inflammatory response driven in part by the release of proinflammatory cytokines and activation of innate immune pathways. One mediator implicated in this response is macrophage migration inhibitory factor (MIF), which is upregulated following TBI along with its receptor CD74. While MIF/CD74 signaling has been shown to regulate the astrocytic responses to injury, its role in peripheral and central immune responses following TBI remains unclear. Here, the effects of antagonizing MIF/CD74 signaling on immune response to TBI was investigated.
Because sex differences in TBI pathology and immune reactivity have been reported, we assessed sex as a biological variable in age-matched mice. Male and female C57BL/6J mice underwent sham or mild-to-moderate fluid percussion injury (FPI) to the left hemisphere. Vehicle (Veh) control or ISO-1, a MIF antagonist, was administered 30 minutes post-injury to inhibit MIF/CD74 signaling. Brains were collected one day post-injury for flow cytometric analysis of innate and adaptive immune populations in both hemispheres.
Male FPI+Veh mice exhibited a higher frequency of CD45high infiltrating peripheral immune cells in the ipsilateral hemisphere compared to female FPI+Veh (p=0.0404) and male Sham+Veh (p=0.0045). Female FPI+ISO-1 mice showed reduced frequency of CD45high activated macrophages in the ipsilateral hemisphere relative to the contralateral hemisphere (p=0.0308), an effect not observed in males.
These results highlight sex-specific neuroimmune responses following mild-to-moderate TBI and suggest a role for MIF/CD74 signaling in modulating immune cell infiltration and activation after injury.
Sexual Arousal Measurement in Women with Spinal Cord Injury: A Pilot Study Using Laser Speckle Contrast Imaging
1University of Minnesota, Minneapolis, United States, 2Hennepin Healthcare Research Institute, Minneapolis, United States
Sexual function is a top-ranked priority for restoration among women with spinal cord injury (SCI), yet it remains among the least objectively studied outcomes in SCI research. Current assessment relies on patient-reported outcome measures developed in able-bodied populations, which fail to capture the injury-specific autonomic and sensory changes that shape sexual response after SCI. Objective physiological measurement is needed — both to understand the neurobiology and to evaluate emerging interventions.
Laser speckle contrast imaging (LSCI) is a non-contact optical technique that quantifies cutaneous blood perfusion in real time. We present a pilot study applying LSCI to measure vulvar blood flow during sexual arousal in women with and without SCI. Participants (n = 2 SCI, n = 3 able-bodied) completed one to four laboratory visits during which vulvar perfusion was recorded continuously while viewing neutral and erotic visual stimuli, alongside continuous subjective arousal ratings and standardized questionnaires.
LSCI successfully captured perfusion responses across all participants. Preliminary findings reveal substantial inter-individual variability in baseline perfusion and time-to-peak response, with attenuated responses observed in women with SCI. These results support LSCI as a feasible, objective endpoint for studying genital arousal after neurological injury and for evaluating neuromodulation interventions targeting sexual function recovery in this population.
Sildenafil Improves Mitochondrial Bioenergetics and Reduces Anxiety-Like Behavior Following Repeated Mild Blast Traumatic Brain Injury
1University of Kentucky, Lexington, United States, 2Lexington Veterans' Affairs Healthcare System, Lexington, United States
Repeated mild traumatic brain injury (rmbTBI) is associated with persistent neurological deficits in military personnel that can arise from secondary cerebrovascular and metabolic impairments. Critically, there are no FDA-approved therapeutics for rmbTBI. Phosphodiesterase-5 (PDE-5) inhibition has been explored in preclinical and clinical TBI studies; however, its exact therapeutic mechanism is not fully understood. Recent data demonstrates that PDE5 inhibition can rescue mitochondrial dysfunction. As such, we hypothesized that PDE5 inhibition with sildenafil has a distinct role in restoring mitochondrial health following rmbTBI that improves neurobehavioral outcomes. To model rmbTBI, male rats were exposed to two 11 psi static peak overpressure blast waves 24hr apart. Animals were randomized into sham or rmbTBI groups and received daily vehicle or sildenafil treatment (5 or 20 mg/kg) beginning after blast exposure (N = 5-8/group). At 7d post-rmbTBI, sildenafil restored reduced hippocampal expression of the mitochondrial biogenesis regulator PGC-1α. Transcriptomic analysis revealed enrichment of oxidative phosphorylation pathways in sildenafil-treated animals, and metabolomic profiling indicated that rmbTBI led to cortical accumulation of glycolytic intermediates and altered NAD redox balance, both attenuated by sildenafil. To assess the mitochondrial signature of brain capillaries after PDE5 inhibition, we show that sildenafil restored mitochondrial bioenergetics in capillaries following AAPH-induced oxidative stress and rmbTBI. rmbTBI increased anxiety-like behavior at 3d and 7d post-injury, which was normalized by sildenafil. Together, these findings demonstrate that rmbTBI disrupts mitochondrial function and behavior, and PDE5 inhibition restores these alterations, supporting sildenafil’s potential as a therapeutic intervention for blast-induced TBI.
Sleep Deprivation After Traumatic Brain Injury Reveals Selective Hypothalamic Inflammatory Signaling
1University of Colorado, Boulder, United States, 2University of Michigan, Ann Arbor, United States
Sleep disturbances are among the most common and debilitating consequences of TBI. Both experimental and clinical evidence demonstrate sleep fragmentation, characterized by increased sleep-wake transitions following injury; however, the mechanisms linking disrupted sleep to inflammatory signaling in the brain remain poorly understood. Because hypothalamic hypocretin (orexin) neurons stabilize sleep-wake transitions and are highly sensitive to inflammatory signaling, we hypothesized that sleep deprivation following TBI would reveal region-specific neuroinflammatory transcriptional responses within hypothalamic circuitry.
Mice underwent diffuse TBI using the midline fluid percussion injury model or sham surgery. Immediately following injury, mice were assigned to sleep deprivation or undisturbed sleep for 6-hours. The hypothalamus, hippocampus, thalamus, motor cortex, and somatosensory cortex were collected for transcriptional profiling using the NanoString nCounter Neuroinflammation Panel. Differential expression analyses were performed using linear modeling with false discovery rate correction, and pathway enrichment was assessed using KEGG-based gene set enrichment analysis.
Across regions, sleep deprivation produced stronger transcriptional effects than TBI alone. Region-specific analysis revealed that the hypothalamus exhibited the largest molecular response, with 23 genes significantly altered by sleep deprivation, whereas other regions showed minimal transcriptional changes. Differentially expressed genes included regulators of inflammatory and intracellular signaling pathways. Pathway enrichment analysis identified coordinated regulation of MAPK signaling, innate immune activation, cytokine signaling, and complement pathways.
The hypothalamus exhibits sensitivity to sleep deprivation following TBI and may represent a mechanistic link between post-traumatic sleep fragmentation and hypothalamic neuroinflammatory signaling. Targeting inflammatory signaling within hypothalamic sleep-wake regulatory circuits represents a novel strategy to stabilize sleep following TBI.
Sleep Fragmentation Exacerbates Brain-Lung Axis Dysfunction After TBI in AD-Predisposed Mice
1University Of Miami Miller School of Medicine, Department of Neurological Surgery, Miami, United States, 2Bruce W. Carter Department of Veterans Affairs Medical Center, Miami, United States, 3University Of Miami Miller School of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, Miami, United States
Traumatic brain injury (TBI) has long-term consequences beyond acute effects, including cognitive dysfunction, behavioral changes, and an increased risk of neurodegenerative disorders such as Alzheimer’s disease (AD). Individuals with TBI frequently develop comorbidities such as sleep disturbances and impaired pulmonary function, both of which are associated with poorer prognosis and accelerated cognitive decline. This study investigated the interactions between TBI and disrupted sleep, with a particular emphasis on how their convergency influences respiratory function and AD-related neuropathology. Age-matched wild type (WT) and 3xTg AD-predisposed mice were subjected to controlled cortical impact (CC) injury, followed by 3, 4, or 7 days of acute sleep fragmentation (SF) to disrupt their sleep-wake cycle. Outcomes included inflammatory profiles, cerebral and pulmonary perfusion, tissue morphology, cognitive performance, and respiratory mechanics. SF increased inflammasome proteins (caspase-1, ASC, IL-1β, GSDMD), with greatest elevations in AD-predisposed groups, accompanied by increased Aβ protein expression in both organs. SF significantly reduced cerebral and pulmonary perfusion, particularly in AD mice. Lung histopathology showed alveolar septal thickening and inflammatory cell infiltration, while behavioral testing at 7 days post-injury revealed cognitive impairments in AD-predisposed animals after SF. Respiratory function was also altered in AD mice, with further deterioration following SF. Collectively, these findings reveal a complex interaction among TBI, sleep disruption, and AD genetic predisposition across the brain and the lung, underscoring the role of sleep and the brain-lung axis in TBI outcomes. Targeting sleep health may represent a critical therapeutic strategy to improve multiorgan function and attenuate AD-related pathological processes following TBI.
Sleep Quality Trajectory and Working Memory in Mild Traumatic Brain Injury: A Longitudinal Comparison by Baseline PSQI Severity
1Taipei Neuroscience Institute, Taipei Medical University, Taipei, Taiwan, 2Division of Neurosurgery, Department of Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan, 3Department of Neurosurgery, Taipei Medical University Hospital, Taipei, Taiwan, 4Neuroscience Research Center, Taipei Medical University, Taipei, Taiwan, 5Ph.D. Program in Medical Neuroscience, Taipei Medical University, Taipei, Taiwan
Background: Mild traumatic brain injury (mTBI) accounts for 70–90% of traumatic brain injuries worldwide, affecting approximately 42 million people annually. Despite being classified as “mild,” many patients experience persistent post-concussive symptoms. Sleep disturbance is one of the most common sequelae, affecting 50–80% of patients and increasingly associated with cognitive deficits, including impaired working memory. The Pittsburgh Sleep Quality Index (PSQI) is a validated measure of sleep quality, with scores >8 indicating clinically significant impairment. However, the longitudinal relationship between baseline sleep disturbance and cognitive outcomes after mTBI remains unclear. This study examined whether baseline sleep severity predicts changes in sleep quality and working memory one year following mTBI.
Methods: A total of 220 patients with mTBI completed the PSQI and Digit Span task (Forward, Backward, Total) at baseline and one-year follow-up. Participants were categorized as poor sleepers (PSQI >8; n=129) or good sleepers (PSQI ≤8; n=91). Paired t-tests assessed within-group PSQI changes, and independent t-tests compared Digit Span performance between groups.
Results: Overall PSQI scores improved significantly over one year (p<.05), driven by improvement in poor sleepers, while good sleepers remained stable. Although Digit Span scores were similar at baseline, poor sleepers showed significantly lower Digit Span Forward and Total scores at one-year follow-up (p<.05).
Conclusions: Baseline sleep disturbance predicts poorer working memory outcomes one year after mTBI, highlighting the importance of early sleep assessment and targeted intervention.
Social Context and Neural Processing in Traumatic Brain Injury: Network Size, Social Contact, and Homophily
1University of South Florida, Tampa, United States
Objectives: To determine how specific aspects of social context—network size, social contact, and homophily—are associated with neural processing dynamics in individuals with traumatic brain injury.
Methods: This preliminary study was conducted within an ongoing hyperbaric oxygen therapy trial with Service Members and Veterans with traumatic brain injury (n = 12). Social context was operationalized using egocentric social networks, defined as individuals (alters) directly connected to a participant, capturing immediate sources of interaction and support. Network measures included size and homophily. Social contact was assessed using an item from the Mayo-Portland Adaptability Inventory-4 capturing ease of social interaction. These variables were integrated with electrophysiological data collected via electroencephalography during an image-based semantic recognition task. Neural responses were examined using event-related potential components, including the N400 and P3. Exploratory t-tests assessed associations between social variables and timing of neural responses.
Results: Social contact demonstrated the largest observed effect (Cohen’s d = 2.1), with lower scores (greater difficulty in social interaction) associated with delayed neural integration in parietal regions. Network size showed a strong effect (d = 1.4), with smaller networks linked to slower semantic integration. Homophily demonstrated a large effect (d = 1.9), with greater social insularity associated with heightened attentional responses in central regions.
Conclusions: Social context is strongly associated with electrophysiological markers of cognitive processing following traumatic brain injury. These preliminary findings suggest that both network structure and lived social interaction experiences shape neural efficiency and attentional demand. Ongoing analyses with additional participants will further refine these associations.
Sub-acute Sociability Changes in Yucatan Minipigs Following Mild Traumatic Brain Injury
1Virginia Commonwealth University, Richmond, United States, 2Richmond Veterans Affairs Medical Center, Richmond, United States
Traumatic brain injury (TBI) is a significant health issue impacting millions of Americans annually, with the majority of reported TBIs being categorized as mild. Despite this nomenclature, mild TBI (mTBI) may lead to significant short- and long-term deficits, including social disengagement. However, little is known about mTBI-induced changes in sociability. Pigs are highly translational models with cytoarchitecture and inflammatory systems similar to humans and consequently, can emulate the impacts of mTBI on the gyrencephalic brain. Therefore, the current study investigated sociability changes in Yucatan minipigs following mTBI to evaluate potential translational similarities with clinical sociability changes. For this, we induced either sham or a mTBI via a central fluid percussion injury (cFPI) on adult male (n = 5/group) and female (n = 4/group) Yucatan minipigs. Approachability to known and unknown humans was assessed over a 1-week timeframe using the voluntary human approach task (VHAT). While there were no noted effects of sex or familiarity with the human on approachability, there was a significant injury effect, in which pigs sustaining mTBI demonstrated lower approachability scores compared to sham control animals (F1,4=5.56, p = 0.02). Specifically, sham animals increased approachability to both known and unknown humans over time while animals with mTBI retained a consistent level of approachability throughout the 1w post-injury period. By 1-week post-injury, mTBI animals showed significantly lower approachability toward humans compared to sham (p = 0.00059), indicating that cFPI in minipigs recapitulates subtle sociability changes sub-acutely following TBI. Funding was provided by NINDS grants R21NS126611 and R01NS128104.
Synergistic Effects of Nicotine and Oral Contraceptive Exposure on Mild Traumatic Brain Injury Outcomes in Female Rats
Dr. Juliana Sanchez2, Dr. William Javier Moreno2, Ms. Indy Cabeda Diaz1, Dr. Helen Bramlett2,
1Department of Neurology, Miller School of Medicine, University of Miami, Miami, United States, 2Department of Neurosurgery, Miller School of Medicine, University of Miami and Bruce W. Carter Department of Veterans Affairs Medical Center, Miami, United States, 3Department of Neurology, Miller School of Medicine, University of Miami and Bruce W. Carter Department of Veterans Affairs Medical Center, Miami, United States
Nicotine exposure through electronic cigarettes (EC) and oral contraceptive (OC) use are prevalent among women of reproductive age; however, their combined impact on traumatic brain injury (TBI) outcomes remains poorly understood. We tested the hypothesis that nicotine and OC exposure interact to exacerbate mild TBI outcomes through transcriptomic alterations in the female brain. Adult female rats were exposed to EC aerosol generated from 5% nicotine JUUL pods using the EcigAero Aerosol Exposure System for 16 days (16 episodes/day over 8 hours). Control animals were exposed to air. A separate cohort received OC or placebo during the 16-day EC exposure period. On day 17, rats underwent mild fluid percussion injury (1.5–1.7 atm) or sham surgery and survived for either 16 or 30 days. Cortical tissue collected 16 days post-TBI was subjected to RNA sequencing. Animals surviving for 30 days underwent behavioral assessment, including motor testing using the cylinder task and cognitive evaluation using the Morris water maze, followed by histopathological analysis. Cortical contusion volume, was significantly greater in EC-exposed rats compared with air-exposed controls, indicating that chronic nicotine exposure exacerbates structural brain injury. Transcriptomic analysis revealed marked cortical gene expression changes following combined EC+OC exposure, with 737 genes upregulated and 536 downregulated. Gene ontology analysis demonstrated enrichment of pathways involved in dopaminergic and serotonergic signaling, calcium-regulated exocytosis, SNARE complex assembly, and endoplasmic reticulum calcium homeostasis. The combined EC+OC exposure worsens TBI outcomes in females, highlighting an under recognized risk factor relevant to women’s brain health.
Funding: VA-BLRD-BX006223-01A1 and FDOH 20K09.
Synthetic PreImplantation Factor Protected Against Blast-Induced Traumatic Brain Injury
1Walter Reed Army Institute of Research, Silve Spring, United States
Blast-related casualties are a significant concern in the military. No effective countermeasures were developed against blast-induced traumatic brain injury (bTBI) though clinical reports indicate that 80% of brain injuries in service members with mild TBI are related to blast exposure. The PreImplantation Factor (PIF), an endogenous embryo-derived peptide provides integrated local and systemic immune protection. Synthetic PIF (sPIF) replicates PIF structure and function and is effective in wide-ranging non-pregnancy related disorders including TBI. Here we tested sPIF efficacy against bTBI using our clinically relevant ferret model. Ferrets were exposed to two tightly coupled blasts (19psi) under anesthesia using an advanced blast simulator. sPIF efficacy was evaluated at two different doses (0.75 and 1.25 mg/kg) administered subcutaneously at 1hr and 6hr post-blast with treatment continuing twice daily until euthanasia. Neurobehavioral functional outcomes were assessed at different intervals up to 1-month. They included open field locomotion test (for anxious and depressive-like behaviors), novel object recognition test (NOR, for short-term memory function), actigraphy measurements for sleep pattern and gait analysis using CatWalk XT system. Study results revealed that sPIF protects against blast-induced development of anxious-like behavior, short-term memory loss, sleep pattern disruption and abnormal gait in a dose-dependent manner. Neuropathological outcome measures at 1-month post-blast supported the observed functional outcomes suggesting/positioning sPIF as promising bTBI therapy.
Targeted Reconstruction of Pro-regenerative Gene Expression Programs in Adult Corticospinal Tract Neurons
1Marquette University, Milwaukee, United States
Background: Adult corticospinal tract (CST) neurons exhibit limited regenerative capacity following spinal cord injury, due in part to a failure to spontaneously activate essential regeneration-associated gene programs. In contrast, axon injury in other neuronal cell types (e.g. sensory neurons, zebrafish retinal ganglion cells) triggers widespread changes in gene expression accompanied by successful axon regeneration. Clarifying the patterns of gene expression that explain this regenerative success and mimicking it in normally non-regenerating neurons may help to improve axon growth after spinal injury.
Methods: We gathered prior transcriptional profiles of regeneration-competent cell types and intersected them with growth cone proteomics, yielding a target set of transcripts that are commonly up- and down-regulated during successful axon regeneration. Next, using retrograde AAV transduction, we forced expression of candidate transcription factors (Sox11, Klf6, Jun, Atf3) and activators of cellular stress pathways in CST neurons in adult mice, followed by transcriptional profiling via single-nucleus RNA sequencing. The resulting differentially expressed gene sets were compared to the target set of regeneration-associated gene changes.
Results: Expressed as the percentage of target genes that shifted significantly in the expected direction (Wilcoxon Rank Sum Test), the effects of single transcription factors ranged from minimal (Atf3, <3%) to moderate (Sox11, 44%). Combined expression of Jun and Atf3 also produced moderate effects (54%), while artificial activation of a cellular stress pathway produced the largest effect (75%).
Conclusion: snRNA-Seq monitoring of gene expression allows systematic, rational reconstruction of pro-regenerative gene expression, a pre-requisite for successful axon regeneration after spinal injury.
Targeting Microbial Poly-N-acetylglucosamine Reduces Neuroinflammation and Improves Neurological Outcomes Following Traumatic Brain Injury
1Massachusetts General Hospital, Boston, United States, 2Harvard Medical School, Boston, United States, 3Tufts University, Medford, United States, 4University of Missouri School of Medicine, Columbia, United States, 5Brigham and Women's Hospital, Boston, United States
Objective: Chronic traumatic encephalopathy (CTE) involves persistent neuroinflammation, yet initiating mechanisms remain elusive. We investigated whether microbial poly-N-acetylglucosamine (PNAG) acts as a nidus for sterile inflammation and if targeting it improves outcomes.
Methods: Post-mortem human CTE tissues and controls were examined for PNAG and phosphorylated tau (p-tau). In mice, PNAG accumulation and behavioral outcomes were assessed following closed-head injury. Biological effects were evaluated via direct PNAG administration. Finally, the therapeutic efficacy of passive antibody treatment and active vaccination against PNAG was assessed.
Results: In human CTE, PNAG increased with disease stage and colocalized with p-tau in pathological regions. After mouse head injury, PNAG rapidly accumulated and persisted in cortex, hippocampus, and striatum near neurons and microglia. Direct striatal PNAG administration induced dose- and sex-dependent weight loss and motor impairments. Notably, passive antibody treatment and vaccination reduced brain PNAG levels and improved motor performance in repetitive closed-head injury models. One year after repetitive injury, vaccinated mice demonstrated sustained improvement in neurological function and reduced microglial activation.
Conclusion: Persistent microbial-derived PNAG is detectable in both human CTE and experimental murine head injury. Reducing PNAG-containing microbial material decreases neuroinflammation and preserves neurological function. These findings suggest that PNAG is a novel translational target for mitigating progressive neurodegeneration and cognitive deficits following traumatic brain injury.
Targeting Peripheral T-cell Infiltration to Mitigate Long-Term Neurobehavioral Impairment in Pediatric Repetitive Mild TBI
1Department of Neurosurgery, Virginia Commonwealth University, Richmond, VA, 23298, USA., Richmond, United States, 2Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA, 23298, USA., Richmond, United States
Pediatric repetitive mild traumatic brain injury (rmTBI) is a major public health concern with links to cognitive dysfunction, anxiety, and depression. The underlying mechanisms of neuroinflammation in pediatric rmTBI are not well understood. The objective of this study was to examine the impact of peripheral immune cell infiltration and subsequent neuroinflammation on white matter (WM) disruption and neurobehavior outcomes. Our Central Hypothesis is that pediatric rmTBI alters brain development and long-term neurobehavior through CD4 T-cells infiltration impacting the functionality of myelinating oligodendrocyte lineage cells (OLC). Our prior study (Shumilov et al., 2026) using p P21 mice with a weekly rmTBI frequency have shown T-cell dependent increased infiltration of activated macrophages, CD8/CD4 T-cells, as well as increased density of astrocytes and microglia. Using the same juvenile rmTBI model, two months after injury, Diffusion Tensor Imaging was used to analyze WM structural disruption, light-dark box, and Barnes maze behavioral tests were performed to evaluate memory and anxiety-like behavior. Preliminary data indicates that two months following rmTBI, subjects exhibited significant memory impairments. Notably, the absence of T-cells mitigated these deficits, whereas the depletion of regulatory T-cells exacerbated them. Furthermore, decreased Fractional Anisotropy in the CC was detected two months after injury. These findings suggest that rmTBI triggers WM disruption and neurobehavioral impairments, probably associated with the infiltration of T-cells. Our future goal is to develop noninvasive therapy to reduce T-cell infiltration, prevent disruption of WM connectivity, and prevent neurobehavioral impairments, leading to improved treatment and reducing the long-term burden of children with rmTBI.
Tau Isoform Expression Drives Disease Outcomes Following a Single Closed Head Injury
1SUNY Downstate Health Sciences University, Brooklyn, United States
Tau dysfunction contributes to axonal injury and impaired axonal transport that is seen in experimental and clinical TBI studies. Tau isoform expression is hypothesized to influence TBI disease progression. Adult human brains express six tau isoforms, containing either three (3R) or four (4R) microtubule-binding sites; adult mice only express 4R isoforms. 3R tau binds tubulin with lower affinity, making microtubules more flexible. Neurodegeneration studies suggest the pathogenicity of specific tau isoforms, but the roles of individual isoform are largely uncharacterized in experimental TBI. The course of brain injury is compared between C57/BL6 mice (WT), and C57/BL6 mice with a knock-in of the coding region of the human microtubule associated protein tau (MAPTKI). WT mice express only murine 4R tau, whereas MAPTKI mice express human 3R and 4R tau. At subacute times after injury (14 days post injury (DPI)), MAPTKI have less white matter damage than injured WT mice. Injured WT mice have greater corpus callosum 4R tau loss, impaired transport, and demyelination than injured MAPTKI. In contrast, at 90DPI, injured MAPTKI mice have corpus callosum demyelination and 4R tau loss while injured WT mice remyelinate. Greater white matter damage in WT mice at 14DPI likely contributes to spatial memory deficits that are absent in MAPTKI mice. Greater white matter damage in MAPTKI mice contributes to spatial memory deficits at 90DPI that have recovered in WT mice. These data strongly suggest human tau isoform expression changes both the subacute and chronic disease course of head injury.
TBI-Induced solTNF/TNFR1 Activity Promotes Amyloid Beta Generation and Neurological Deficits, without Impacting Microglial Phagocytosis of Amyloid Beta
1Virginia Commonwealth University, Dept. Surgery, Richmond, United States, 2Barrow Neurological Institute, Dept. Translational Neuroscience and Neurology, Phoenix, United States
Introduction: Traumatic brain injury (TBI) is a known risk factor for Alzheimer’s disease (AD)—increasing the soluble form of the inflammatory cytokine Tumor Necrosis Factor (solTNF), which is implicated in AD progression and microglial dysfunction. SolTNF/TNFR1 may be the crucial mediator between TBI and AD.
Methods: Adult (3 month) male 3xTg-AD mice received a TBI (single moderate CCI, or sham) and XPro1595 (10 mg/kg S.C.;30 min post-injury followed by twice weekly), to selectively inhibit solTNF/TNFR1 (or vehicle). Ipsilateral hippocampi were collected at 1-, 3-, 7DPI, 1-, 4-, or 7MPI with flow cytometry and WBing used to evaluate amyloid production and clearance, paired with neurological function (Barnes maze and Von Frey) at all time points.
Results: WBing reveals that injury promotes a slow increase in BACE1 levels over time (from 1DPI to 7MPI: cf. sham-injured mice), corresponding with a temporary peak in Aβ42 levels sub-acutely (3-7DPI), which was prevented in mice treated with XPro1595. Flow cytometry reveals that injury promotes a reduction in the total number of microglia with age (CD11bhiCD45low), and that these microglia are less reactive sub-acutely (CD11bhiCD45lowCD36+ cells), corresponding with an increased ability to phagocytose (CD11bhiCD45lowCD36+Methoxy04+ cells), independent of XPro1595 treatment. Neurological testing reveals that injury impaired function, which was prevented with XPro1595 treatment, at almost all timepoints tested.
Conclusions: Here, TBI transiently increased Aβ sub-acutely, leading to lasting neurological deficits which are prevented when inhibiting solTNF/TNFR1 activity post-injury. Microglia in younger mice are less reactive after injury with increased ability to phagocytose, independent of solTNF/TNFR1 activity.
The COVID Effect: National Changes in Neurotrauma Injury Patterns, Imaging, and Resource Utilization in U.S. Emergency Departments
1Texas Tech University Health Sciences Center El Paso, El Paso, United States
Introduction/Objective: Emergency departments (EDs) serve as the primary point of care for traumatic head injury in the United States. During the COVID-19 pandemic, EDs underwent substantial operational changes nationwide; however, their impact on head injury evaluation, neuroimaging utilization, and provider involvement remains unclear. We aim to characterize these changes during the pandemic period.
Methods: Using the 2018-2022 National Hospital Ambulatory Medical Care Survey (NHAMCS), we analyzed head injury visits identified using ICD-10-CM S00-S09 codes. Visits were characterized into pre-pandemic (2018-2019) and pandemic (2020-2022) periods. The NHAMCS design variables were used to evaluate patient demographics, injury characteristics, imaging utilization, provider involvement, medications, and resource availability.
Results: We identified 4,296 ED visits for head injury. Pandemic visits involved older patients (37.9 vs 34.4 mean years of age, p=0.042) and greater diagnostic complexity (2.48 vs 2.17 mean number of diagnoses per visit, p=0.036). Imaging utilization increased during the pandemic including head CT (55.9% vs 50.3%, p=0.021), and X-ray usage (30.9% vs 26.3%, p=0.046). Provider involvement expanded, with higher rates of attending physician involvement (85.4% vs 81.0%, p=0.036) and EMT involvement (13.6% vs 9.7%, p=0.038). Injury classification patterns also differed across the periods (p<0.001), with fewer overdose/poisoning-related visits and a small increase in visits related to adverse effects of medical and surgical treatment.
Conclusion: Emergency department evaluation of head trauma shifted substantially during the COVID-19 era, with increased neuroimaging utilization and broader provider involvement. Understanding these shifts may help inform future emergency preparedness and optimize neurotrauma care delivery during healthcare system strain.
The Developing Injured Brain Is Not Quiet: Automated Microglia Morphology Analysis Reveals Rapid Region-specific Changes After Diffuse Traumatic Brain Injury
1Virginia Commonwealth University, Richmond, United States
Traumatic brain injury (TBI) remains a leading cause of death and disability in young children, yet the underlying biology of TBI during early development is poorly understood and largely extrapolated from adult studies. Microglia, play significant roles during development and injury, however, little is known regarding acute neuroinflammatory progression following TBI during early development. To address this, our group used a central fluid percussion injury (cFPI) model of TBI in postnatal day 16-18 old male and female rats, which approximates a human toddler. This model produces clinically relevant features, including apnea despite no gross structural damage. To investigate acute neuroinflammatory changes, we applied high-dimensional morphological analysis using MicrogliaMorphology ImageJ plugins and the MicrogliaMorphologyR package to quantify 27 structural features of individual Iba-1-labeled microglia within the cortex, thalamus, and subcortical white mater in pediatric rats sustaining sham injury or cFPI. Assessments were done at 30min, 1hr, 3hr, 6hr, 12hr, and 1d post-injury (n=2-3 animals/group). Hard k-means clustering of microglia within each region indicated morphological clusters that were distinct for each region encompassing varying levels of process network complexity, cell size, and cell shape, enabling precise data-driven characterization of activation patterns. Further shifts in microglial morphology toward various activated clusters appear to precede peak burden of diffuse axonal injury, indicating rapid and region-specific microglial activation in the injured pediatric brain. This approach offers a powerful and scalable framework to define microglial responses in the developing brain. This work was funded by the Children’s Hospital of Richmond Foundation Research Fund Grants.
The Effect of Concussion and Sport Participation on Self-Reported Measures of Brain Health: A CARE Consortium Study
1Michigan Concussion Center, Ann Arbor, United States
Sport participation is frequently associated with head impact exposure and/or concussion, which have potential negative consequences to long-term brain health, particularly years after sport retirement. The objective of this investigation was to evaluate self-reported measures of brain health in former collegiate athletes and military service academy cadets, 5-10 years following exposure.
Former collegiate athletes and military service academy cadets (N=11,246) completed a battery of assessments through a customized online survey portal 5-10 years following their athletic or cadet career. The battery included: BSI-18, SCAT symptom severity; PROMIS-Pain Interference, PSQI, SWLS, and the PHQ-9. The percentage of individuals exceeding established clinical thresholds for each measure were evaluated by the level of head impact exposure (i.e., high, low, unexposed) and diagnosed lifetime concussion history (i.e, 0, 1-2, 3+).
A dose-response relationship was observed between the number of prior concussions and the likelihood of exceeding a clinical threshold. Those with three or more prior injuries had exceeded thresholds (as high as 62.9%), relative to those with one to two (51.9%) and no prior concussions (40.1%). There was a variable effect of head impact exposure across outcome measures, with the unexposed group reporting the highest percentage of individuals exceeding clinical thresholds (as high as 50.1%), relative to the low (41.4%) and high (43.8%) exposure groups.
These findings suggest that a higher number of lifetime concussions is associated with poorer brain health up to 10 years following a collegiate career – presenting a critical opportunity for early intervention to potentially prevent negative long-term outcomes.
The GITR Drain: A Multimodal Neuromonitoring Device for Detection of Spinal Cord Injury and Systematic Review of Associated Literature
Dr. Serban Negoita1
1University of Florida, Gainesville, United States
To advance detection of pathologic spinal cord injury we propose a multimodal neuromonitoring approach enabled by a device titled the GITR (Guided Intrathecal Reconnaissance) Drain. By enabling simultaneous measurement of spinal cord evoked potentials (SCEP), as well as access to cerebrospinal fluid (CSF) for measurement of injury markers and pressure, the GITR drain can help enable multimodal care to optimize intraoperative and postoperative care (Figure 1).
Here we present initial GITR drain prototypes with associated validation impedance and percutaneous placement validation. As an indicator the performance of this modality in detecting hypoperfusion, we also present a systematic review of SCEP performance in detection of post-operative deficit from ischemic injury.
Methods: A total 203 patients undergoing SCEP monitoring were included across 9 retrospective case series (Table 1). For the systematic review of SCEP performance in detecting spinal cord ischemia, sensitivity, specificity, positive and negative predictive value were utilized as primary outcomes. For device development GITR drain electrodes were microfabricated via photolithography and Polyimide and Titanium deposition. Impedance was verified through Electrode impedance spectroscopy at each stage of fabrication.
Results: We demonstrate that impedance remains at clinically utilizable levels (average 6250 Ohms) through the GITR drain production process while maintaining passage through 14G Tuohey needles (Figure 2). The sensitivity of SCEP monitoring using a 20% decrement in amplitude for new neurologic deficit was 100% (32/32) and the positive predictive value was 75.0% (21/28). All patients with transient amplitude changes were neurologically intact (38/38). The specificity was 96.2% (175/182) and the negative predictive value was 100% (175/175) (Table 2).
The Impact of Traumatic Brain Injury on the Chirality and Interactions of Neurons and Microglia During the Acute Phase Post-injury
1Department of Natural Sciences, CASL, University of Michigan-Dearborn, Dearborn, United States
Cell chirality, a recently discovered fundamental property of cells, has been shown to play a distinctive role in diverse developmental and physiological processes within tissues and organs. However, in the brain, the chirality of various cell types remains poorly understood. This study aimed to elucidate the chirality of microglia and neurons, their interactions, and the effects of traumatic brain injury (TBI) on these behaviors. Male and female C57BL/6 mouse littermates (postnatal day 20–21) were randomly assigned to either Sham or TBI cohorts (n=24 per group; 12 males/12 females). Animals in the TBI group underwent a standardized injury protocol, while Sham group received anesthesia without injury. Neurons and microglia were concurrently isolated from corresponding brain regions in both groups and seeded onto custom-fabricated micropatterns to assess chirality and cell interactions; gene expression profiles were also analyzed separately. Results demonstrated that TBI induces distinct patterns of neuronal and microglial chirality, along with changes of chirality-associated genes. Notably, microglia exhibited a non-chiral-dominated chirality with a weak counterclockwise (CCW) bias (chiral factor = -0.133), whereas TBI induced a pronounced CCW bias (chiral factor = -0.452). In contrast, neurons did not exhibit obvious chirality and showed little influence from TBI. Additionally, the positioning of cell organelles (e.g., mitochondria) and the interactions between neurons and microglia were altered under the TBI condition. These findings suggest that microglial chirality is a dynamic cellular parameter influenced by TBI, offering a potential biomarker for brain injury assessment and a target for therapeutic intervention to improve outcomes following TBI.
The Prevalence of Multiple Concussions in Professional Football Players: A Scoping Review
1Boston Children's Hospital, Boston, United States, 2McGaw Medical Center of Northwestern University, Chicago, United States, 3University of Massachusetts Chan Medical School, Worcester, United States, 4Harvard Medical School, Boston, United States
Objectives: Sport-related concussions in professional American football are associated with increased risk of neurodegenerative disease, yet the cumulative effects of repeated head injury remain poorly understood due to inconsistent classification and reporting criteria. We conducted a scoping review to characterize variability in concussion exposure measurement and reporting in professional American football players.
Methods: Ovid Medline, Embase, CINAHL, Cochrane, and PsychInfo were searched following PRISMA guidelines, supplemented by snowball searching. Eligible studies included peer-reviewed articles reporting concussion metrics in active or former professional American football players with multiple (>1) concussions. Studies were excluded if they enrolled only non-professional players, did not specifically assess concussion, or included subjects with complex concussion. Of 21,399 records screened, 44 were included.
Results: The majority of studies (35/44) relied on self-reported concussion history, with 16 using categorical survey responses that varied substantially in exposure range and grouping. Among the 8 self-reported studies capturing full exposure ranges, maximum reported concussions per player ranged from 7 to 50. Only 7 studies used clinician-diagnosed concussion databases; in the single such study reporting maximum exposure frequency in 12 seasons, the highest individual burden was 7 concussions. This variation in measurement approach precluded meaningful cross-study comparisons.
Conclusions: Concussion reporting in professional American football research is highly heterogeneous, driven by reliance on self-report and inconsistent exposure categorization, which limits the ability to characterize dose-response relationships between concussion burden and long-term neurologic outcomes. Standardized, prospective surveillance protocols are needed to generate reliable exposure data to inform player safety and clinical care.
The Relationship Between Blood-Based Biomarkers and Alterations in Consciousness Following a Mild Traumatic Brain Injury
1Medical College of Wisconsin, Milwaukee, United States, 2University of Washington, Seattle, 3University of California, San Fransisco, San Fransisco,
Recent multidimensional models of traumatic brain injury (TBI) characterization, such as the CBI-M (clinical-biomarker-imaging-modifiers) model, have recommended using blood-based biomarkers along with clinical signs and symptoms of injury (e.g., loss of consciousness [LOC], posttraumatic amnesia [PTA], and retrograde amnesia [RGA]) to effectively describe TBI. However, these clinical and biomarker features are not routinely documented in emergency departments. To integrate biomarkers and clinical signs into TBI characterization, there is a need to clarify their relationship, particularly in mild injuries with no other objective injury markers. N=171 participants with Glasgow Coma Scale 14-15 injury and no head computed tomography findings were enrolled within 24 hours of injury and evaluated with a blood draw and semi-structured interview capturing clinical signs of TBI. N=126 participants also completed a 2-week blood draw. Common biomarkers of TBI, including glial fibrillary acidic protein (GFAP), ubiquitin C-terminal hydrolase-L1 (UCH-L1), tau, and neurofilament light (NF-L) levels were evaluated at each timepoint and as a mean across time. One-way ANOVAs were run to investigate the association between log-transformed biomarkers and LOC, PTA, and RGA. LOC was associated with higher levels of Day 1 and mean GFAP (ps=.01-.007, η2 = .053-.058) and UCH-L1 (ps<.001, η2 = .082-.092). RGA was associated with higher levels of all biomarkers (ps ranging from .006 to <.001, η2s ranging from .044 to .109). PTA was not associated with any biomarker measure. The relationship between biomarkers and clinical signs may motivate clinicians to thoroughly document clinical signs of injury and incorporate a multidimensional approach to characterizing TBI.
The Renin–Angiotensin System Mediates Vascular Remodeling Following Spinal Cord Injury
1Dalton Cardiovascular Research Center, Columbia, United States, 2Department of Pathology and Anatomical Sciences, Columbia, United States, 3Nextgen Precision Health, Columbia, United States, 4Department of Medical Pharmacology and Physiology, Columbia, United States, 5Department of Physical Medicine and Rehabilitation, Columbia, United States
Cardiovascular disease is a leading cause of long-term mortality following spinal cord injury (SCI), yet the vascular mechanisms driving this remain poorly understood. SCI disrupts supraspinal sympathetic control of the circulation, producing chronic hypotension and altered neurohumoral signaling. These changes are predicted to dysregulate the renin–angiotensin system (RAS), a key regulator of vascular tone and remodeling. We hypothesized that chronic RAS activation after SCI promotes arterial remodeling and stiffening through angiotensin II type 1 receptor (AT1R)–dependent signaling. Adult female rats underwent a complete T4 spinal cord transection. Eight weeks post-injury, plasma analyses revealed increased circulating angiotensin II and reduced ACE activity, consistent with a shift toward vasoconstrictive RAS signaling. To determine how these changes affect vascular structure and mechanics, femoral (conduit) and mesenteric (resistance) arteries were isolated and studied ex vivo using pressure myography. Femoral arteries exhibited reduced diameter consistent with inward remodeling, likely reflecting reduced limb blood flow and diminished shear stress associated with inactivity following SCI. In contrast, mesenteric arteries displayed pronounced inward remodeling and increased incremental elastic modulus, indicating pathological stiffening of resistance vessels. To test whether AT1R signaling mediates this phenotype, mesenteric arteries were incubated overnight with vehicle, the AT1R antagonist losartan, or a LIM kinase inhibitor. Both treatments increased arterial strain in SCI vessels relative to vehicle, indicating reduced stiffness following inhibition of AT1R signaling. These findings identify Ang II–AT1R signaling as a driver of resistance artery stiffening and highlight this pathway as a potential therapeutic target to reduce cardiovascular risk.
The Role of Blast-induced Hearing Loss in Driving Alzheimer's-Related Neuropathology
1University Of Miami, Coral Gables, United States
Blast exposures cause inner ear and neurological damage, inducing two major Alzheimer's Disease (AD) risk factors: traumatic brain injury and hearing loss. This study investigates how blast-induced hearing loss drives cognitive decline and AD progression via pro-inflammatory mechanisms. Using a blast model in wild-type and APOE4 mice, we will assess functional outcomes and inflammatory expression post-trauma. APOE4 and wildtype mice (n=4/genotype; 19–20 weeks) were exposed to a blast under anesthesia. Sham control groups (n=4/genotype) received anesthesia but were not exposed to blast. To assess hearing damage, auditory brainstem responses were measured across a range of frequencies at baseline and on days 7, 14, and 28 post-blast. Day 28 post-blast revealed significant shifts in ABR thresholds at all frequencies tested in WT and AD blasted mice when compared to WT and AD shams (*p < 0.05) suggesting permanent auditory dysfunction. Blast exposure significantly increased cerebrovascular dysfunction in the AD-blast when compared to the WT-Sham (*p < 0.01). AD-Blast had a significantly higher cerebrovascular dysfunction compared to the WT-Blast (*p < 0.05) indicating an association between blast and genotype. Behavior assessment through Barnes Maze suggests spatial learning and memory deficits. Chronic inflammation was observed from cochlear tissue collected at Day 28 with significant expression of pro-inflammatory cytokines when compared to WT-Sham. In the cortex, pro-inflammatory expression of TNF-α was observed when comparing WT-Sham to AD-Blast. We have established a preclinical model that effectively captures complex interactions between hearing loss induced by blast, functional damage and pro-inflammatory alterations and long-term neurocognitive loss.
The Unprotected Epidemic: Escalating Incidence and Clinical Severity of E-Scooter Related Traumatic Brain Injury
1School of Medicine, University of California, Davis, 2College of Biological Sciences, University of California, Davis, 3Department of Neurological Surgery, University of California, Davis, 4Department of Pharmacy, University of California, Davis, 5UC Davis Health, Sacramento, 6Department of Neurology, University of California, Davis, 7Department of Physical Medicine & Rehabilitation, University of California, Davis
Objectives: Rapid electric (e-) scooter proliferation has precipitated a surge in micromobility-related traumatic brain injuries (TBI). TBI is the leading cause of e-scooter-related mortality, yet helmet utilization remains low and safety regulations are inconsistent. This study characterizes the prevalence, severity, and risk factors of e-scooter-related TBIs within a major metropolitan trauma center system to inform public health intervention and neurotrauma policy.
Methods: We conducted a retrospective cohort study of patients admitted to a Level I Trauma Center with TBI following e-scooter accidents (2011-2025). The cohort was stratified by sociodemographic data, helmet utilization, and admission toxicology. Clinical outcomes included Glasgow Coma Score (GCS) and hospital length of stay (LOS). Statistical significance was determined using T-tests and Chi-squared tests (p<.05).
Results: Helmet utilization among patients with e-scooter TBIs (n=104) was 7.69% (n=8); among children (n=35), 5.71% (n=2) were helmeted. Helmet use was significantly associated with higher GCS (95% CI: [1.03-2.38], p<.001) and shorter hospital LOS (95% CI: [-5.36 to -1.29, p=0.002). Substance use on presentation was prevalent: 29.81% positive for alcohol, 42.31% positive on toxicology testing. Notably, e-scooter-related TBI cases increased 100.00% between 2023 and 2024, signaling an acceleration in the regional neurotrauma burden.
Conclusion: Escalating e-scooter-related TBIs, compounded by low helmet compliance and intoxication, represent a burgeoning public health crisis. These data underscore the need for targeted injury prevention programs, stricter helmet enforcement, and policy shifts to mitigate the neurological consequences of micromobility accidents.
Therapeutic Targeting of the Thrombin Receptor in Chronic SCI Promotes Functional Gains and Improvements in Lipid Metabolism
1Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, United States, 2Center for Regenerative Biotherapeutics, Mayo Clinic, Rochester, United States, 3Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, United States, 4Regenerative Sciences, Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, United States
Aberrant activation of the thrombin receptor, Protease Activated Receptor 1 (PAR1) after spinal cord injury (SCI), resulting from blood–spinal cord barrier disruption and increased protease release from activated glia and immune cells contributes to the secondary injury cascade. PAR1 knockout mice show improved outcomes after SCI, however whether therapeutic PAR1 targeting can recapitulate these results is not well understood. Here, we demonstrate that delivery of a PAR1 antagonist (SCH79797) initiated 2-weeks after T10 complete compression SCI in 12-week-old female mice improves sensorimotor recovery and signs of neural resiliency and repair. Mice receiving SCH79797 showed increased counts of NeuN+ neurons, GAP43+ growth cones, PDGFRα+ oligodendrocyte progenitors and GST3+ mature oligodendrocytes, in addition to reduced Iba1+ microglial/monocyte reactivity and astrocyte-associated pro-inflammatory properties (C3d+). The underpinning molecular mechanisms were investigated by Ingenuity Pathway Analysis of differentially expressed genes (DEGs) identified by RNA sequencing of total or astrocyte-specific RNA from the injury epicenter across treatment groups. Mice receiving SCH79797 showed gene enrichment in signaling pathways related to Creb, Ncam and Pdgf. DEGs identified in astrocyte RNA from SCH79797 treated mice showed enrichment in pathways related to the Krebs Cycle, LXR/RXR Activation, and DHCR24 Signaling. SCH79797 treatment also improved astrocyte HMGCS1 production in the context of chronic SCI and in purified astrocyte cultures. Collectively, these findings suggest that PAR1 inhibition in the chronic period after SCI promotes astrocyte energy homeostasis and cholesterol availability that may be leveraged to promote neural resiliency and restoration of axonal, synaptic, and myelin membranes that collectively improve functional outcomes.
Three-Dimensional Morphometric Analysis of Brain Capillary Mitochondria Following Repeated Mild Blast Traumatic Brain Injury
1University of Kentucky, Lexington, United States, 2Spinal Cord and Brain Injury Research Center, Lexington, United States, 3Department of Physiology, Lexington, United States, 4Lexington VA Healthcare System, Lexington, United States
Traumatic brain injury (TBI) affects millions globally and remains a leading cause of persistent neurological dysfunction. In military populations, mild blast TBI (mbTBI) is increasingly recognized as a signature injury of modern warfare, and this injury has been associated with neurovascular dysfunction. Reports show that blast TBI leads to oxidative stress in blood vessels, implicating mitochondrial dysfunction in the vasculature. Despite growing recognition of vascular involvement in blast TBI pathology, how mbTBI reshapes mitochondrial morphology within the cerebrovascular network remains to be fully elucidated. This study aims to quantify mitochondrial morphology within isolated cerebral capillaries following repeated mbTBI (rmbTBI) using high-resolution three-dimensional (3D) reconstruction. Male and female transgenic mice expressing a mitochondrial fluorescent reporter Dendra2 (mtD2) were used to visualize mitochondria within intact capillaries. Mice (n=4/sex/group) were subjected to rmbTBI using the McMillan blast device, consisting of two 11 psi exposures separated by 24h. Animals were evaluated at 1, 7, 30, and 60 days post-injury, and sham controls underwent identical handling procedures without blast exposure. Cerebral capillaries were isolated, co-stained with WGA and imaged using confocal microscopy to acquire z-stack images. Reconstruction using Imaris enabled mitochondrial segmentation for quantitative morphometric analysis. There is a non-significant decrease (p=0.054) in mitochondrial volume fraction for rmbTBI group compared to sham at 60d post-rmbTBI, which is driven by a significant decrease (p=0.031) in female rmbTBI group compared to its respective sham group. Collectively, these findings demonstrate the feasibility of interrogating capillary mitochondrial morphology following TBI and potential female aging vulnerability following rmbTBI.
Time-Dependent Alterations in HPA Axis Regulation Following Diffuse Traumatic Brain Injury
1University of South Florida, Tampa, United States, 2University of Arizona College of Medicine - Phoenix, Phoenix, United States, 3Barrow Neurological Institute at Phoenix Children's, Phoenix, United States
Traumatic brain injury (TBI) is frequently followed by delayed or worsening neuropsychiatric symptoms, including depression, anxiety, and post-traumatic stress disorder, across the injury severity spectrum. Dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis has been proposed as a contributing mechanism but has not been systematically evaluated across chronic post-injury intervals. To approximate the trajectory of HPA axis regulation following diffuse TBI, circulating corticosterone (CORT), brain glucocorticoid receptor (GR) expression, adrenal weight, and circuit-related Wallerian degeneration were evaluated across multiple cohorts. In male rats, morning (light-phase) plasma samples and brain biopsies were collected from cohorts at different time points after midline fluid percussion injury (mFPI) and analyzed for circulating CORT and GR expression across acute-to-chronic post-injury intervals. At 56 days post-injury, adrenal weight was normalized to body weight, and amino cupric silver staining was used to evaluate Wallerian degeneration in white matter tracts relevant to HPA axis feedback.
Diffuse TBI was associated with time-dependent endocrine alterations extending through two months post-injury. Circulating CORT was elevated acutely (6–24 h), similar to sham levels at ∼7 days, and ∼60% lower than shams at two months post-injury. At this chronic time point, restraint stress–evoked CORT responses were also blunted. Endocrine changes occurred alongside dynamic GR adaptations in hypothalamus and amygdala, differences in adrenal weight, and significant Wallerian degeneration in white matter tracts. These findings support multiphasic alterations in HPA axis regulation following diffuse TBI, suggesting that endocrine signaling and stress responsivity change dynamically after injury rather than following a simple declining trajectory.
Timing of Decompressive Craniectomy and Outcomes in Pediatric Patients with Traumatic Brain Injury: A Systematic Review and Meta-analysis
Mr. Osnar Lima1, Ms. Samanda Sousa2,
1Federal University of Maranhão, Sao Luis, Brazil, 2Uninovafapi University Center, Teresina, Brazil, 3Houston Methodist Hospital, Houston, United States, 4University of Sao Paulo, Sao Paulo, Brazil
Objectives: Evidence regarding the timing of decompressive craniectomy (DC) in pediatric traumatic brain injury (TBI) remains inconclusive. This study compares outcomes between early and late DC in the pediatric population.
Methods: We searched PubMed, Embase, and Cochrane for studies comparing early (<2 to <24h) to late (>2 to >24h) DC in patients aged <18 years. Outcomes included favorable 6-month Glasgow Outcome Scale (GOS), in-hospital mortality, and length of stay (LOS). Mean difference (MD) and Odds ratios (OR) were employed. Random-effects models and subgroup analyses (ultra-early: <2h; early: <6h; conventional early: <24h) were performed.
Results: Four studies (769 patients; early:439; late:330 DC) were included. Overall, no significant difference was found in favorable GOS (OR 1.58; 95% CI 0.68–3.67; p=0.29) or mortality (p=0.10). However, ultra-early intervention was associated with higher mortality (OR 3.19; 95% CI 2.14–4.76; p<0.001), while the 24h cut-off showed no difference. Early DC significantly reduced LOS overall (MD -8.12 days; 95% CI -10.63 to -5.60; p<0.001) and across all timing subgroups (p<0.05).
Conclusion: Early intervention appears to shorten hospital stays without compromising long-term outcomes. However, the higher death rate within <2h suggests either a bias towards more severe cases or risks associated with immediate treatment. These findings should be viewed with caution because of the limited number of studies. Future research should focus on using standardized, physiologically based criteria instead of strict time limits.
Toward Clinical Implementation of Blood Biomarkers for Traumatic Brain Injury: Analytical Harmonization and Reference Standard Development in the INFORM-TBI Consortium
1University Of Pittsburgh, Department of Neurosurgery, Pittsburgh, United States, 2University of Pennsylvania, Philadelphia, USA, 3Foundation for Applied Molecular Evolution, Alachua, USA, 4University of British Columbia, Vancouver, Canada, 5Children's Hospital of Eastern Ontario, Ontario, Canada, 6University of Messina, Messina, Italy
Objective: Blood biomarkers offer a promising approach to improve diagnosis, stratification, and monitoring of traumatic brain injury (TBI). However, their translation into clinical practice has been limited by analytical variability across platforms and the absence of standardized reference materials. The International Network Focused on Optimizing Research for Markers in Traumatic Brain Injury (INFORM-TBI), funded by the National Institute of Neurological Disorders and Stroke (NINDS), was established to address these barriers through coordinated analytical validation and harmonization of leading neurotrauma biomarkers.
Methods: Recombinant reference materials characterized by mass spectrometry are being developed for key biomarkers, including ubiquitin C-terminal hydrolase-L1 (UCH-L1), glial fibrillary acidic protein (GFAP), neurofilament light (NfL), total tau, brain-derived tau (BD-Tau), and phosphorylated tau (pTau-181/231). Analytical comparability was evaluated through head-to-head testing across widely used assay platforms. In addition, plasma samples from the Canadian Health Measures Survey were analyzed to establish biomarker population reference intervals and assess cross-assay agreement.
Results: Initial analyses demonstrated strong correlations between Single Molecule Array (Simoa) assay configurations for NfL and GFAP, confirming robust consistent detection of biological signal. However, systematic quantitative biases between assay formulations were identified, underscoring the need for calibration against standardized reference materials to achieve measurement comparability. Age-stratified reference intervals were also derived, providing essential benchmarks for clinical interpretation.
Conclusion: These findings demonstrate that rigorous analytical harmonization and the establishment of standardized reference materials are essential for ensuring comparability of blood biomarker measurements and represent a critical step toward their reliable integration into clinical trials and routine clinical care for TBI.
Transcranial Neuromodulation for Epileptogenesis Prevention in the Sleep-Disrupted Injured Brain
1Florida International University, Miami, United States
Sleep disruption (SD) and traumatic brain injury (TBI) both contribute to post traumatic epilepsy (PTE) risk. TBI alone is a known cause of sleep disturbances and PTE, studies suggest sleep loss following TBI can intensify neuronal injury, resulting in more severe long-term consequences. However, whether chronic SD before injury increases the risk of PTE has not been established. We investigated whether chronic SD prior to injury enhances epileptiform hyperexcitability and whether transcranial magnetic stimulation (TMS) can mitigate these pathological network changes. Mice were assigned to 4 groups: SHAM, SD only, TBI only, and SD TBI. SD was induced for two weeks using automated chambers prior to TBI using a weight drop model. Animals underwent long term EEG and EMG monitoring to quantify interictal spikes, fast ripples, and sleep architecture. Repetitive TMS was applied daily for 14 days after TBI. SD TBI mice showed significant increases in epileptiform activity. Fast ripples increased approximately 3–4 fold, while interictal spikes increased 19–24 fold. Sleep analysis revealed alterations in sleep architecture, particularly in SD TBI animals, which showed higher NREM sleep (74–76%) and reduced REM sleep (0.5%), compared to TBI (63% NREM, 2–3% REM). Because epileptiform activity and fast ripples preferentially occur during synchronized NREM states, these alterations may create a network environment that promotes pathological synchronization and hyperexcitability. Importantly, TMS treatment reduced fast ripple activity by 54.5%, decreased spike activity, and partially improved sleep architecture, suggesting that early neuromodulation may attenuate post traumatic network hyperexcitability and limit epileptogenesis after TBI.
Transcriptional Metabolic Reprogramming after Spinal Cord Injury: Dysregulation of Glucose and Lipid Metabolism with Mitochondrial Dysfunction
1Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, USA
Traumatic spinal cord injury (SCI) induces profound secondary disturbances in cellular metabolism that exacerbate tissue damage and functional deficits. To investigate these changes, we performed transcriptome-wide RNA sequencing of rat spinal cords at 3 h and 24 h after SCI. Differential expression analysis revealed striking reprogramming of glucose metabolism, mitochondrial function, and lipid pathways. We identified a pronounced shift toward glycolysis, evidenced by significant upregulation of Hk2, Pfkl, Pgk1, Eno1, and Ldha, accompanied by activation of the pentose phosphate pathway. In contrast, mitochondrial glucose oxidation was impaired, reflected by downregulation of Pdha1 and Pdhb together with induction of inhibitory kinases Pdk1 and Pdk4, indicating suppression of pyruvate dehydrogenase (PDH) activity. Nearly all genes encoding tricarboxylic acid (TCA) cycle enzymes (Cs, Aco2, Idh2, Ogdh, Mdh2) and subunits of respiratory complexes I–V were significantly downregulated after SCI, indicating transcriptional suppression of oxidative phosphorylation. Lipid metabolism showed extensive dysregulation: fatty acid biosynthesis genes (Acaca, Acacb, Fasn) were suppressed, cholesterol pathway genes (Hmgcr, Fdps, Sqle) were dynamically regulated, and triacylglycerol enzymes (Dgat1, Dgat2) were elevated. Furthermore, we observed robust transcriptional activation of phospholipases (Pla2g2a, Pla2g4a) and eicosanoid biosynthetic enzymes (Alox5, Alox15, Ptgs1, Ptgs2, Lpcat2, Ptges, Ptges2, Ptges3, and Tbxas1), alongside a reprogrammed sphingolipid rheostat favoring sphingosine-1-phosphate production. Collectively, these findings demonstrate that SCI drives coordinated transcriptional reprogramming of glucose and lipid metabolism, leading to enhanced glycolysis, PDH inhibition, mitochondrial dysfunction, and bioactive lipid signaling. Targeting these pathways may provide novel therapeutic strategies to restore metabolic balance and limit secondary injury after SCI.
Transcriptional Profiling and Immunohistological Assessments of Thalamic Glia During the Subacute Phase of Diffuse Traumatic Brain Injury in Swine
1Department of Neuroscience and Anatomy, Virginia Commonwealth University School of Medicine, Richmond, United States, 2VCU Massey Comprehensive Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, United States
Diffuse traumatic brain injury (TBI) initiates evolving neuroinflammatory cascades with consistent thalamic involvement. However, transcriptional programs governing subacute glial responses are incompletely understood, particularly in translational models with cytoarchitecture and glial biology similar to humans, such as swine. To address this gap, we performed single-nucleus RNA sequencing on thalami collected 1w after sham or central fluid percussion induced TBI in adult male and female Yucatan swine. 35,000 nuclei/group were sequenced at a depth of 30,000 reads and analyzed using a pipeline including alignment to the sus scrofa reference, quality control to remove sub-par and doublet nuclei, normalization, unsupervised/unbiased clustering, and cell-type annotation. Distinct neuronal and glial clusters were identified, including multiple microglial and astrocytic subclusters. Pathway enrichment analyses revealed strong baseline enrichment of mitochondrial metabolic pathways, including oxidative phosphorylation and respiratory electron transport in sham females vs. sham males (all p<0.0001). Following TBI, males showed enrichment of cytoskeletal and axonal signaling pathways, including RHO GTPase signaling, ROBO receptor signaling, and axonal guidance compared to sham (all p<0.0001). Females demonstrated further enrichment of mitochondrial metabolic pathways and stress responses such as EIF2 signaling and nonsense-mediated decay 1w post-TBI vs. sham (all p<0.0001). Further, initial complementary 3D immunohistochemical reconstructions demonstrated greater microglial process convergence onto inured axonal swellings in females compared to males (0.55 vs. 0.22 contacts/µm), with a similar pattern observed for astrocyte process convergence (0.36 vs. 0.19 contacts/µm). Together, these findings identify injury- and sex-dependent metabolic and structural glial responses within the swine thalamus sub-acutely post-TBI.
Funding: NINDS R01NS128104, R56NS128104.
Transcriptional Profiling of Spinal Cord Macrophages Following Treatment with LPS-MSC-Derived Nanovesicles
1Spinal Cord and Brain Injury Research Center and Dept. Physiol., Univ. of Kentucky, College of Medicine, Lexington, United States, 2Department of Chemistry, Univ. of Kentucky, Lexington, United States
Following the primary spinal cord injury (SCI), a cascade of secondary injury mechanisms—including oxidative stress, excitotoxicity, and persistent neuroinflammation—drives progressive tissue damage and functional decline. Macrophages play a central role in this process; although initially involved in debris clearance, sustained polarization toward a pro-inflammatory (M1-like) phenotype amplifies neuronal loss and impairs recovery. Mesenchymal stem cell-derived nanovesicles (MSC-NVs) primed with Lipopolysaccharide (LPS) represent a potential therapeutic approach to shift the injury environment toward a reparative state. This study aimed to characterize the transcriptional profile and phenotypic identity of macrophages within the injured spinal cord following treatment with LPS-MSC-NVs. Sixteen female C57BL/6 mice underwent T9 contusion SCI and received LPS-MSC-NVs or vehicle control. Macrophages were isolated from spinal cord tissue at 7 days post-injury using a 26%/70% Percoll density gradient. Total RNA was extracted using a Qiagen RNeasy Plus-Micro kit. Samples were pooled (n=2 per group) to ensure adequate RNA yield, producing eight biological replicates. Global gene expression was analyzed using bulk RNA-sequencing. Transcriptomic analyses revealed substantial transcriptional reprogramming of spinal cord macrophages following LPS-MSC-NV treatment. Pathway enrichment analysis revealed significant downregulation of tumor necrosis factor (TNF)-associated processes, including TNF-α production and cytokine signaling, compared with phosphate-buffered saline (PBS) controls. Consistent with these changes, M1-associated genes were significantly downregulated, whereas anti-inflammatory M2-associated transcripts, including Arg1 and Mrc1, were markedly upregulated. These findings demonstrate that LPS-MSC-NVs redirect macrophage polarization toward a pro-regenerative state, highlighting their potential as a therapeutic strategy to mitigate secondary injury after SCI.
Transfer times to Tertiary Admission in Children with Mild Traumatic Brain Injury and Implications for Six Hour Observation Guidelines
1University Of California Davis, Sacramento, United States
Objective: The Pediatric Brain Injury Guidelines (p-BIG) identify children with traumatic intracranial hemorrhage who can be safely discharged from the emergency department (ED) after short-term observation. Children with BIG-1 injuries are often subject to time consuming transfers exceeding the recommended six-hour observation period while at low risk of neurological deterioration. To inform our practice and minimize unnecessary patient transfer to a regional center, we evaluated time of injury to transfer to tertiary arrival among children with BIG-1 injuries.
Methods: We retrospectively reviewed children aged 0-17 years with mild traumatic brain injury (GCS 14-15) and BIG-1 injury transferred to a tertiary pediatric trauma center. Time from injury to arrival was calculated using trauma registry timestamps and transfer center documentation. Descriptive statistics and Pearson correlation assessed the relationship between time to arrival and Injury Severity Score (ISS).
Results: Forty-seven children met inclusion criteria. Mean time from injury to arrival was 8.52 hours (median 6.27 hours, IQR 4.51-8.85). Over half (55%) arrived beyond six hours from the time of injury. Time to arrival was not associated with ISS (r = -0.084, p = 0.57). No child experienced neurological deterioration (decrease in GCS ≥2 points) nor required neurosurgical intervention after transfer.
Conclusions: Most children with BIG-1 injuries arrived after the six-hour observation period had elapsed, indicating that recommended observation can be safely and feasibly completed at the initial hospital. These findings support implementation of a local BIG-1 management pathway, with specialty trauma and neurosurgical consultation, to reduce potentially avoidable transfers while maintaining patient safety.
Translational Trauma Model Defines Dose-Response, Repair Mechanisms, and Biomarkers of Adenosine Receptor Agonist AST-004 in Human Astrocytes
1UCLA, Geffen Sch Medicine, Semel Institute, IDDRC, Los Angeles, United States, 2Dept. of Computational Medicine, Statistics Core, School of Public Health, Los Angeles, United States, 3Astrocyte Pharmaceuticals Inc., Cambridge, United States, 4University of Texas Health Science Center at San Antonio, San Antonio, United States
Traumatic brain injury (TBI) causes progressive neurological deficits with no FDA-approved therapies. To address this gap, we developed an in vitro human astrocyte trauma model using controlled pressure pulses applied to elastic-bottom cultures to evaluate efficacy, mechanisms, target engagement, and biomarker responses to the adenosine receptor agonist AST-004. Persistent membrane disruptions (propidium iodide uptake, %PI+) were used as cyto-analytic outcomes for dose titration. AST-004 reduced %PI+ cells compared to untreated trauma (Cohen’s d=1.3SD units, p<0.0001, linear mixed model, posthoc Tukey). Optimal AST-004 efficacy was estimated at 1.8nM (6donors, n=218 unbiased algorithm-analyzed images, 2-3,000cells/8mm2, 12doses). AST-004 reduced pyknotic cell death (d=1.1; p=0.001) and enhanced membrane repair of cells with partial nuclear condensation (d=1.7-2.7; p<0.0001). Trauma induced a 3.5-fold increase in pyknosis-associated GFAP-filament unwinding, which AST-004 reduced by half (d=1.4, p=0.0004). Distinct astrocyte morphotypes differed in PI+ cells (process-overlapping>fibrous>protoplasmic astrocytes; subpopulations explained 22% of the variance, F=123, p<0.0001, n=171). Trauma reduced the proportion of aligned astrocyte patterns by half, which AST-004 increased (d=1.4, p=0.038). AST-004 also elevated mitochondrial respiration in astrocytes with processes (single-cell JC10-ratiometry, p=0.001, n=29, 7hrs postinjury). Human astrocytes expressed A1 and A3 adenosine receptors (immunofluorescence, immunoblotting). Adenosine receptor antagonists abolished AST-004 injury protection (d=1.1, DPCPX, p=0.03; MRS1523/7799, p=0.001), suggesting dual receptor-mediated signaling. Finally, AST-004 attenuated trauma-release of astrocyte injury-defined biomarkers (densitometry: ALDOC, CRYAB, BLBP, GFAP and α2-spectrin degradation). This trauma platform provides mechanistic insights into membrane repair, adhesion, respiration, target engagement, and proteostasis, supporting human astrocyte survival, and link these responses to pharmacodynamic biomarker monitoring of therapeutic efficacy.
Acknowledgement: SRA- AstrocytePharmaceuticals:award#20220214;DanaFoundation:award#20182601.
Traumatic Brain Injury and HSV-1 Infection Interact To Alter Post-Injury Sleep Architecture in Mice
1University of Colorado, Boulder, United States, 2University of Colorado Anschutz Medical Campus, Aurora, United States
TBI disrupts sleep architecture and increases sleep fragmentation. Viral infection may further modify these effects. Herpes simplex virus-1 (HSV-1) is a neurotropic virus that establishes lifelong latency following primary infection. We hypothesized that latent HSV-1 infection would alter sleep responses following TBI.
Adult mice (n = 32) were intranasally infected with HSV-1 (McKrae strain, 106 PFU) or vehicle. Fourteen days later, mice underwent closed head controlled cortical impact or sham surgery. Sleep was continuously monitored throughout the experiment.
HSV-1 infection alone did not alter overall sleep duration during the infection period (p > 0.15), but transiently disrupted sleep architecture during peak infection. Sleep bout length was significantly reduced on days 6 and 7 post-infection (p=0.001 and p=0.002), with ∼46–47% shorter bouts, while sleep-wake transitions increased on days 5 and 6 (p < 0.05), indicating increased sleep fragmentation during peak viral activity.
Following injury, TBI significantly increased sleep fragmentation (∼71% increase in transitions, p < 0.001). HSV-1 infection alone increased total minutes slept (∼23%, p=0.015) but significantly modified the TBI sleep phenotype, reducing the injury-associated increase in fragmentation by ∼39% (p=0.010). Both infection and TBI altered circadian sleep distribution, reducing sleep during the dark cycle (p < 0.001). Immunohistochemistry analysis is ongoing to assess neuropathological changes and localization of HSV-1.
Together, these findings demonstrate that HSV-1 infection transiently fragments sleep during peak infection and modifies the sleep response following TBI, revealing a previously unrecognized interaction between neurotropic viral infection and brain injury in regulating sleep.
Traumatic Brain Injury and Sleep Disruption Converge To Promote Alzheimer’s-Related Protein Pathology
1University of Colorado Boulder, Boulder, United States, 2Arizona State University, Tempe, United States
Traumatic brain injury (TBI) increases the long-term risk for Alzheimer’s disease and related dementias (ADRDs), yet the mechanisms linking injury to neurodegenerative pathology remain incompletely understood. Sleep disturbance is a common consequence of TBI and may exacerbate neuronal stress and impair proteostatic clearance. We hypothesized that post-injury sleep disruption amplifies the generation and accumulation of ADRD-associated toxic protein variants and contributes to functional impairment.
Adult male and female mice underwent sham, mild, or moderate midline fluid percussion injury (n = 92). After a 7-day recovery period, a subset of animals underwent 7 days of experimental sleep disruption. Behavioral outcomes were assessed longitudinally using rotarod, neurological severity score, open field, and novel object recognition tasks. Brain tissue collected at 14 days post-injury was analyzed for disease-relevant variants of amyloid-β (Aβ), tau, and TDP-43 across multiple brain regions.
TBI induced accumulation of Alzheimer’s disease-related protein variants with regional patterns resembling early neurodegenerative pathology. Behavioral deficits increased with injury severity (p < 0.05) but largely resolved by 14 days post-injury. However, a subset of mice exhibited persistent impairments accompanied by elevated levels of toxic protein variants. Correlation analyses revealed strong region- and variant-specific relationships between protein pathology and behavioral outcomes, particularly involving tau variants. Females also exhibited significantly higher levels of several pathological variants compared with males (p < 0.001).
Together, these findings identify sleep disruption as a critical modifier of TBI-induced proteostatic stress, promoting early ADRD-related protein pathology and functional deficits following brain trauma.
Traumatic Brain Injury Biomarkers and Deficits Associated with Early Extracranial Surgery: A TRACK-TBI Study
1Clement J. Zablocki VAMC, Department of Anesthesiology, Milwaukee, United States, 2Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, United States, 3Department of Neurological Surgery, University of Washington, Seattle, USA, 4Department of Biostatistics, University of Washington, Seattle, USA, 5Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, USA, 6Department of Epidemiology, Biostatistics, and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, USA, 7Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, USA, 8Department of Neurology, Medical College of Wisconsin, Milwaukee, USA
Introduction: We recently demonstrated that exposure to extracranial (EC) surgery/anesthesia shortly after traumatic brain injury (TBI) is associated with cognitive deficits at acute, sub-acute, and chronic timepoints. These observational data cannot imply a causal relationship and are at risk of confounding. This project will analyze blood-based brain injury biomarkers to test if concentrations: 1) before surgery suggest that the primary insult (TBI) was more severe despite similar clinical presentations and CT scan findings; and 2) increase after surgery suggesting CNS cell death.
Methods: Retrospective/secondary analysis of the TRACK-TBI dataset (a prospective observational cohort study). The primary outcomes were blood concentrations of biomarkers for neurons (UCH-L1) and astrocytes (GFAP) on day 1, 3 and 5 after TBI.
Results: Subjects (n=3047) were 70.0% male, mean (SD) age of 42.6 (17.8) with 1273 non-surgical and 465 EC-surgery patients. There was no difference in GFAP or UCHL-1 concentrations on day one between EC-surgery and nonsurgical participants. GFAP concentrations decreased faster in the EC surgery compared to nonsurgical participants (B -0.22; Exp (B) 0.80; p=0.002). UCHL-1 concentrations before and after EC surgery compared to nonsurgical participants are pending.
Conclusions: Biomarker concentrations did not support that the TBI severity was a confound to the association between EC surgery and adverse outcomes. Also, GFAP decreased by 20% after exposure to EC surgery. Biomarker concentrations could be influenced by production, distribution, metabolism, or hemodilution (perioperative volume resuscitation). These findings do not support the hypothesis that EC surgery results in widespread neuronal or astrocyte cell death.
Traumatic Brain Injury During Pregnancy Disrupts Cortical Development, Evidenced by Differential Gene Expression and Cortical Layer Thickness in Exposed Offspring
1University of Arizona, Phoenix, United States, 2Michigan Medicine Physical Medicine & Rehabilitation, University of Michigan Concussion Center, Ann Arbor, United States
Traumatic brain injury during pregnancy (gravida TBI; gTBI) poses significant risks to the fetus, particularly in cases of intimate partner violence. Brain development is highly orchestrated, and exposure to gTBI could dysregulate gene expression and increase risk for neurodevelopmental disorders, such as autism and schizophrenia. We hypothesized that gTBI would disrupt cortical lamination and associated gene expression in gTBI mouse offspring. We induced midline fluid percussion or sham injury in pregnant dams at embryonic day E12.5. At E16.5, fetal brains (gTBI=2; sham=2) were analyzed using spatial transcriptomics (10x Genomics Visium-HD) in layer-segmented cortical regions (ventricular zone, VZ; subventricular zone, SVZ; intermediate zone, IZ; cortical plate, CP). Cortical lamination at E16.5 was visualized using stained (H&E, Statb2, Tbr1) spatial transcriptomic sections. Qualitatively, cortical regions differed in area between gTBI and sham at the same bregma level. Differentially expressed genes (DEGs) in the VZ were increased 8-fold compared to sham and associated with immune regulation. Conversely, DEGs in the IZ and CP were decreased 32-fold compared to sham and associated with transcriptional regulators of neurulation and cortical development (Tfap2c, Eomes, and Nr2e1) and metabolic activity (Aldoc). Thus, gTBI disrupted gene pathways related to cortical development and cell signaling in the fetal brain, consistent with behavioral manifestations of disrupted cortical development observed in gTBI-exposed juvenile offspring. Altogether, these studies provide insight into the molecular mechanisms that link gTBI exposure to increased risk of neurodevelopmental disorders, warranting urgent public health and medical interventions.
Funding: NICHD R01-HD110860
Traumatic Brain Injury During Pregnancy Risks Synapse Loss and Early Communication Behavior in Exposed Offspring
1University of Arizona, Phoenix, United States, 2Michigan Medicine Physical Medicine & Rehabilitation, University of Michigan Concussion Center, Ann Arbor, United States
Traumatic brain injury during pregnancy (gravida TBI; gTBI) is a significant and understudied risk factor for adverse neurodevelopment. Because the developing brain relies on highly orchestrated processes to establish synaptic connections and functional neural circuits, perturbation during development could promote synaptic dysfunction and risk neurodevelopmental disorders (NDD). We hypothesized that gTBI would alter the number of synaptosomes (isolated pre- and post-synaptic components) and behavior in exposed mouse offspring. We induced midline fluid percussion or sham injury in pregnant mouse dams (n=11) at embryonic day 12.5. We measured ultrasonic vocalizations in response to maternal separation, an early communication behavior in gTBI (n=24) and sham (n=18) offspring at postnatal day P9. gTBI (n=23) offspring emitted softer calls, characterized by a reduced peak amplitude, compared to sham (n=18) (t=2.149, df=40, p=0.037). At PND21, gTBI (n=29) and sham (n=23) offspring exhibited similar learned helplessness, measured by the tail suspension test. At PND28, gTBI (n=14) and sham (n=18) offspring expressed similar anxiety levels in the center of the open-field. Whole brain tissue was collected from a subset of gTBI (n=8) and sham (n=5) offspring to quantify synaptosomes by flow cytometry. Analysis showed a ∼25% decrease in number of synaptosomes in gTBI offspring compared to sham (t=2.344, df=11, p=0.039). Thus, gTBI exposure can alter the number of synapses in gTBI offspring and early post-natal behavior which risks NDD phenotypes seen in early childhood.
Funding: NICHD R01-HD110860.
Traumatic Brain Injury Elicits Multisystem Responses in Hemoglobinopathy: A Bulk RNA-Sequencing Analysis in Berkeley Sickle Cell Mice
1University Of Pittsburgh School of Medicine, Pittsburgh, United States
Hemoglobinopathy, including sickle cell disease (SCD), impacts 300+ million individuals globally. We hypothesize systemic inflammation in SCD exacerbates TBI-induced multisystem injury.
Berkeley SCD and C57BL/6J WT mice (12-18wk, n=2-6 per group) underwent controlled cortical impact (CCI) at 6m/s, 1.6mm depth or identical anesthetization without injury (Sham). Whole blood was collected 72h post-injury and sent for bulk RNA sequencing. Processing raw sequencing data, identification of differentially expressed genes (DEGs) and ranked gene set enrichment analysis with pathways in Mus musculus KEGG database were performed in R (v4.5.1). These analyses assessed SCD genotype x CCI interaction ([SCD-CCI – SCD Sham] – [WT-CCI – WT Sham]).
Pathways differentially upregulated by CCI in SCD vs. WT mice include neutrophil extracellular trap formation, platelet activation, neurodegeneration, cardiac muscle contraction, non-alcoholic fatty liver disease, collecting duct acid secretion, and vasopressin-regulated water absorption (FDR<0.05) Pathways differentially downregulated by CCI in SCD vs. WT mice include cell adhesion molecules, cytokine-cytokine receptor interaction, and hematopoietic cell lineage (FDR<0.05). Key upregulated DEGs include H3 clustered histone 10 (Log2FC 5.8), prothrombin (Log2FC 5.7), purinergic receptor P2y12 (Log2FC 0.9), alpha-synuclein (Log2FC 1.7), and alpha-synuclein interacting protein (Log2FC 3.0). Key downregulated DEGs include peptidyl arginine deiminase 4 (Log2FC -0.5), p-selectin (Log2FC -0.9), and vascular cell adhesion molecule 1 (Log2FC -1.3).
CCI differentially alters expression of multisystem pathways involved in immune signaling and migration, vascular and platelet function, hepatic, renal and cardiac dysfunction and neurodegeneration in SCD vs. WT mice. Ongoing histology and cellular imaging will further characterize multisystem sequelae of TBI in hemoglobinopathy.
Traumatic Brain Injury Results in Severely Disrupted axons in the Cerebellar Cortex
1USUHS, Bethesda, United States
The cerebellum, in addition to its role in coordination and motor activities, has emerged as a key structure regulating important neural functions including sleep, cognition, and emotion. It is therefore crucial to understand the effects of traumatic brain injury (TBI) on cerebellar pathology. To evaluate the TBI effect on human cerebellum we studied brains of military personnel exposed to blast injuries, or those of control subjects not known to be exposed to blast. We also evaluated brains of military service members using boats for special operations, SWCC (Special Warfare Combatant-craft Crewmen). SWCC operate small, military boats at high velocities and are exposed to repetitive impacts during operation. Our previous findings revealed extensive Purkinje cell loss, disrupted Bergman glia, and astrocytic changes in blast injured warriors. We focused our current evaluation of the cerebellar cortex on the structure and distribution of axons using antibodies directed against phosphorylated neurofilament H. The control cerebelli showed axons extending throughout the cerebellar cortex and surrounding Purkinje cells. The immunoreactive axons in control brains populated the full thickness of the molecular layer. In the cerebelli of blast injured warriors and SWCC operators, labeled axons demonstrated significant reductions in axon length. The blast and SWCC injured cerebelli showed abnormal appearing swellings and morphologic changes not observed in the axons of control brains, where the processes were smooth, without terminal enlargements. The injured axons were additionally substantially more disorganized than those in control cerebelli. These data strongly suggest that blast and SWCC operation result in severe cerebellar disorganization.
Treat the Agitation, Keep the Gains: A Preclinical Evaluation of Brexpiprazole After TBI
Connor Pivirotto1,2, Haley Capeci1,2, Prajeet Santra1,2, Jeffrey Cheng1,2, Dr Corina Bondi1,2,
1University of Pittsburgh, Physical Medicine and Rehabilitation, Sewickley, United States, 2Safar Center for Resuscitation Research,
Introduction: Managing agitation following traumatic brain injury (TBI) commonly involves the use of antipsychotic drugs (APDs), despite evidence that D2 receptor antagonists, like haloperidol, disrupt recovery. Identifying APDs that do not hinder recovery is therefore critical for TBI patients. Brexpiprazole, a third-generation APD, exhibits partial agonist activity at D2 and 5-HT1A receptors, a pharmacological profile associated with improved outcomes after experimental TBI. Based on these properties, we hypothesized that brexpiprazole would not adversely affect recovery after TBI and may support improved outcomes.
Methods: Anesthetized adult male rats underwent either a cortical impact (2.8 mm depth at 4m/s) or sham injury and randomized to receive brexpiprazole (0.5, 1.0, or 2.0 mg/kg; i.p.) or vehicle beginning 24 h post-injury for 21 days. Motor function was assessed on days 1-5 and cognitive performance was assessed on days 14-20.
Results: No differences were observed between brexpiprazole and vehicle-treated sham groups and hence they were pooled for analysis. Shams outperformed TBI groups on all behavioral measures (p<0.05). No differences were detected between brexpiprazole and vehicle-treated TBI groups on motor outcomes (p>0.05). However, rats receiving 0.5 mg/kg brexpiprazole demonstrated improved spatial learning compared to vehicle controls and the two higher dose brexpiprazole groups (p<0.05).
Conclusions: Brexpiprazole did not impair recovery following TBI, supporting the hypothesis. Moreover, the lower dose improved spatial learning, suggesting a potential dose-dependent cognitive benefit. Significance: While motor outcomes were unaffected, brexpiprazole’s pharmacological profile warrants further investigation for its potential to manage agitation while preserving and possibly enhancing other behaviors affected by TBI.
Type I Interferon-Driven Microglial Pyroptosis Is Associated with Delayed Thalamic Neuronal Loss After Traumatic Brain Injury
1University Of Iowa, Iowa City, United States
Following traumatic brain injury (TBI), secondary injury cascades such as neuroinflammation drive progressive cellular death and dysfunction. Our lab has shown that type I interferon signaling is upregulated after experimental TBI and is associated with increased thalamic neurodegeneration, although the underlying mechanism remains unknown. This study aimed to define region specific reactive microglial populations after TBI and evaluate their association with delayed neuronal loss.
Adult microglial-specific IFNAR KO and wild-type mice were exposed to lateral fluid percussion injury. ScRNAseq was performed on CD11b+/CD45+ microglia/leukocytes isolated from the ipsilateral forebrain at 7 days post injury (dpi). RNAscope evaluated cell-type-specific and spatial expression of an ISG (Irf7) and a neurodegeneration-associated marker (Spp1) at 7 and 28 dpi. RTqPCR was conducted on ipsilateral thalamic punches at 3/7/14/28dpi. NeuN immunofluorescence quantified neuronal loss at 3/7/14/28dpi.
ScRNAseq data demonstrated multiple heterogenous microglial populations induced by TBI, including an IFN-I responsive microglial subset and several populations characterized by upregulation of genes linked to neurodegenerative disease. RNAscope revealed distinct thalamic microglial populations, with Irf7+ microglia present subacutely and Spp1+ microglial predominating chronically. Region specific RT qPCR confirmed these temporal expression patterns. NeuN staining showed delayed thalamic neuronal loss and a RTqPCR screen of cell death pathways highlighted the pyroptosis (Gsdmd, Casp1, Casp4, Zbp1) and apoptosis pathways (Casp3) at later timepoints. Microglial-specific IFNAR deficiency reduced the IFN-I responsive microglial population, decreased expression of pyroptosis-associated genes, and attenuated thalamic neuronal loss. Ongoing work is investigating how IFN I–mediated microglial pyroptosis contributes to delayed thalamic neurodegeneration after TBI.
UCHL1 Mutations Protect Against Repetitive Mild Traumatic Brain Injury-Induced Impulsive-Like Behaviors and Neuropathic Pain
1Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, School of Medicine, Lubbock, United States, 2Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, School of Medicine, Lubbock, United States, 3Brain Drug Discovery Center, Texas Tech University Health Sciences Center, School of Pharmacy, Lubbock, United States
Traumatic brain injury (TBI) is a chronic health condition affecting over 70,000 people per year, with 80% of these cases being mild. Ubiquitin C-terminal hydrolase L1 (UCHL1) is a biomarker for TBI severity, and functions to maintain protein homeostasis in both neurons and peripheral nerves. A C152A knock-in mutation of UCHL1 has been shown to improve neurological outcomes following stroke and severe TBI, however, the protective role(s) of the C152A mutation following repetitive mild TBI (rmTBI) remains poorly understood. Our rmTBI model increases impulsive-like behaviors and pain sensitivity, and we posit that C152A mice exposed to rmTBI will demonstrate improvements in these functional facets. Baseline locomotion and pain sensitivity was performed prior to a NeuropactorTM device being used to deliver three daily bouts of closed-head (mild) TBI to the dorsal midline head of adult female C152A and wild-type (WT) control mice. Pain sensitivity was evaluated through daily mechanical (digital electro Von Frey) and cold (acetone) sensitivity testing. At one-month post-rmTBI, we measured impulsive-like behavior using the Elevated Plus Maze with brain and blood collected to measure markers of neuroinflammation. Our Central Hypothesis is that UCHL1 mediates rmTBI-induced impulsive-like behavior and pain sensitivity. WT mice exposed to rmTBI demonstrated impulsive-like behaviors (P<0.05) and increased pain sensitivity (P<0.001), which was ameliorated in C152A mice (P<0.001). Results suggest that UCHL1-mediated mechanisms may drive TBI-related impulsivity and neuropathic pain. Future studies will use male mice and additional UCHL1 manipulations to further parse out the implications of our functional TBI-related outcomes in female C152A mice.
Ultrastructural Damage to the Optic Nerve and Retina Induced by a Single High-Intensity Blast Exposure in Rats
Dr. Ming Gu1,2, Dr. Rachel Barkey1,2, Ms. Megan Young1,2, Mr. Jonathan Statz1,2, Dr. Mary Johnson3, Dr. Stephen Ahlers2, Dr. Rania Abutarboush1,2,
1Henry Jackson Foundation, Bethesda, United States, 2Naval Medical Research Command, Silver Spring, USA, 3University of Maryland, Baltimore, USA
Blast-induced traumatic brain injury (bTBI) remains a persistent risk in the military population and is associated with ocular dysfunctions. Exposure of the optic nerve (ON) and retina to blast overpressure (BOP) can result in progressive visual loss and neurodegeneration. However, current understanding of blast-induced traumatic ocular injury is limited, as most experimental studies rely on Sprague-Dawley rats, which lack retina pigmentation. Using Long-Evans rats with pigmented retinas, we previously reported functional retina changes following exposure to a single high intensity of BOP. In the present study, we further investigated structural and pathological changes in the ON and retina using the same blast injury model. Anesthetized rats were exposed to a single frontal BOP of 130 kPa (18.85 PSI) and euthanized 28 days post-blast. Ultrastructural analysis using Transmission Electron Microscopy (TEM) revealed significant thinning of myelin sheaths as well as axonal degeneration in the ON following BOP exposure. In addition, retina ultrastructural abnormalities, including photoreceptor disruption, nucleolus pyknosis and cellular vacuolation were observed in BOP-exposed rats. Immunohistochemical analysis of microglial marker Ionized calcium-binding adaptor molecule 1 (IBA1) and the pro-inflammatory cytokine Interleukin 1 beta (IL1β) demonstrated a significant increase in IBA1 expression in the ON, along with a trend toward increase of IL1β levels in both ON and retina of blast rats compared with sham controls. These findings suggest that BOP induces ocular structural injury through microglial activation and inflammatory process. Our study further elucidates the mechanisms underlying ocular pathology leading to visual deficits in military-relevant bTBI.
Unique Transcriptomic Profiles of Oligodendrocyte Lineage Cells Following Traumatic Brain Injury in Male Mice
1Graduate Program in Translational Biology, Medicine, & Health, Virginia Tech, Blacksburg, United States, 2Department of Biomedical Engineering, Virginia Tech, Blacksburg, United States, 3Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, United States, 4Center for Engineered Health, Virginia Tech, Blacksburg, United States
Neuroinflammation and glial activation are hallmarks of traumatic brain injury (TBI), contributing to secondary pathophysiological cascades after the primary insult. Although classically known for forming and maintaining myelin, oligodendrocyte (OL) lineage cells—including oligodendrocyte precursor cells (OPCs) and mature OLs—also perform non-canonical functions, such as modulating neuronal signaling and neuroinflammatory responses, thereby influencing injury progression and recovery. To date, the mechanisms underlying these activities remain poorly defined. Thus, our team processed and analyzed single-cell RNA-sequencing (scRNA-seq) data generated from pooled hippocampal tissue of male mice subjected to controlled cortical impact (CCI) or sham surgery at 7 and 106 days post-injury to characterize injury-associated transcriptional responses. Exploratory differential expression was performed at the single-cell level using Wilcoxon rank-sum testing and further examined using Ingenuity Pathway Analysis (IPA) to explore trends in signaling pathways and regulatory networks associated with these transcriptional shifts. Relative to the corresponding sham, we identified 343 differentially expressed genes (DEGs) in OPCs 7 days post-CCI, 78 in OPCs 106 days post-CCI, 1740 in OLs 7 days post-CCI, and 216 in OLs 106 days post-CCI (FDR < 0.05, |log2FC| ≥ 0.25). IPA revealed pathway-level alterations associated with neuroinflammation, metabolic regulation, extracellular matrix (ECM) remodeling, and ECM signaling dynamics, providing mechanistic context for subsequent investigation. Our findings provide molecular insights into how OL lineage cells contribute to both maladaptive and reparative processes following TBI, with the potential to reshape current perspectives on OL and OPC involvement in brain injury and recovery.
Usage of AI for PubMed Analysis in Preclinical Traumatic Brain Injury Abstracts
1University Of Pittsburgh, Pittsburgh, United States, 2Howard University, Washington, United States
The rapid expansion of biomedical literature makes manually curating information both expensive and time-consuming, making it difficult to stay on pace with rapid research growth. The PREclinical Interagency reSearch resourcE (PRECISE-TBI) model catalog (https://scicrunch.org/precise-tbi) was created as an online resource to enhance reproducibility by centralizing metadata for TBI preclinical models. Currently, the model catalog relies on manual curation, which limits its scalability. To explore a semi-automated approach for metadata extraction, using Gemini-2.5-Flash, independently tested against a control group of two human curators. A dataset of 120 PubMed abstracts from the PRECISE-TBI model catalog was retrieved using NCBI E-utilities to extract parameters including sex, TBI model type, strain, and species. The accuracy of the information extracted was evaluated by calculating the percent agreement with the human-curated dataset. Analysis of the data collected shows that Gemini-2.5-flash achieved an overall agreement of 94% with specific agreements for each parameter being 99% for sex, 88% for strain, 93% for TBI Model type, and 94% for species. This study shows that Gemini can be used at a high level of proficiency to extract experimental metadata from preclinical TBI abstracts, but it should be done with caution. Thus, its outputs should be paired with another automated method, such as the rule-based method, to increase extraction accuracy. These automated methods can reduce the curation time burden and resources required to support PRECISE-TBI’s mission of creating a sustainable, living catalog.
Using Implementation Science to Improve Discharge Education for Concussion in Emergency Departments: Health System Outcomes from the EDucate Study
1Medical College of Wisconsin, Milwaukee, United States
Although providing concussion information at emergency department (ED) discharge is recommended, clinicians often fail to recognize the injury and deliver appropriate education. The federally funded EDucate study applies implementation science strategies to improve concussion discharge education for adults. This abstract reports on the study’s initial phase, which aimed to (1) identify determinants of providing discharge education and (2) evaluate the impact of evidence-based implementation science strategies on clinicians’ delivery of educational handouts. In Fall 2024, we surveyed 115 clinicians and interviewed 29 clinicians across 7 EDs to assess barriers to providing concussion discharge education. Analysis revealed system-level barriers (e.g., time constraints, electronic health record [EHR] limitations), clinician factors (e.g., limited knowledge of diagnostic criteria, variable attitudes toward diagnosing concussion), and patient-level challenges (e.g., acute cognitive impairment, low literacy and health literacy). Using an iterative, community-engaged process, we matched and prioritized evidence-based implementation strategies. Strategies centered on the September 2025 deployment of an ED Discharge SmartSet, designed to consolidate recommended discharge practices—including modern, standardized educational handouts—into a single, accessible place in the EHR. Across more than 1,200 concussion and head injury encounters, SmartSet usage increased from 18% in Month 1 to 48% in Month 5. Moreover, incorporating the SmartSet increased the primary study outcome—the percentage of head injury encounters for which a concussion handout was provided—by approximately 10% from the pre-implementation baseline to implementation Month 5. Findings support the value of community-engaged strategies and offer guidance for building better systems of concussion care.
Utilization of SV2A PET Imaging for Monitoring of Synaptic Alterations After Traumatic Brain Injury
1University of Pittsburgh, Pittsburgh, United States
Traumatic brain injury (TBI) is frequently associated with deficits across cognitive, emotional, and somatic functions that contribute to reduce quality of life for patients living with a TBI. Synaptic alterations are associated with impaired function in the acute to chronic post-injury recovery period. Our group previously demonstrated that changes in synaptic vesicle trafficking and fusion contribute to impaired neurotransmission in the injured brain. Synaptic vesicle glycoprotein 2A (SV2A) is a critical mediator that regulates the coupling of calcium to neurotransmission for neuronal communication. The absence of a non-invasive method to monitor and longitudinally track synaptic alterations has slowed understanding of synaptic dysfunction and examination of therapeutic efficacy. SV2A PET imaging has recently emerged as a non-invasive method to monitor changes in SV2A as an indication of synaptic alterations. We hypothesize that fluid percussion injury results in reduced SV2A PET activity in the weeks post-injury. To test this hypothesis, male and female Sprague Dawley rats received either fluid percussion injury or sham control surgery. SV2A PET imaging was completed in the weeks following injury. Analysis of standardized uptake value (SUV) in the cortex and hippocampus revealed significant reductions in SV2A activity in FPI-injured rats, as compared to sham control rats. Western blot and immunohistochemical assessments confirm reductions in SV2A abundance at the site of injury. Ongoing work will examine whole brain changes and the time course of SV2A PET activity reductions post-injury.
Vascular Reductions at 60 Days Post Cortical Contusion Injury (CCI) Elicits Sex Associated Differences in BBB Leakage
1University Of California, Riverside, Novato, United States, 2Neurotherapeutics Department, Lundquist Institute for Biomedical Innovation, Torrance, United States
Objectives: Our previously published study observed early vascular recovery followed by vessel loss at 60d post injury (dpi) after traumatic brain injury (TBI) in adult male mice. Vessel loss was coupled with decreased brain perfusion. Our aim was to determine whether vascular loss in female mice also occurred.
Methods: TBI was induced using controlled cortical impact (CCI) at the level of somatosensory cortex in 2-3 months old male and female mice. Sham and TBI mice underwent perfusion weighted MRI and behavioral testing across time points 60dpi, along with brain fixation using our vessel painting protocol. Brains were excised, and axial surface vasculature was microscopically imaged. Vascular features were derived, including vessel density, total vessel length and junction density amongst others. MRI-derived lesion volumes and blood brain barrier (BBB) leakage were measured across temporal time points. Coronal sections were assessed primarily on the ipsilateral side.
Results: The axial and coronal vasculature at 60 dpi exhibited subtle differences between sexes in the ipsilateral cortex. Vessel features at 60dpi in males were reduced compared to previously published data at 1-30dpi. TBI female mice reported increased BBB leakage at 7 and 60dpi compared to their sham counterparts.
Conclusions: TBI results in acute damage to the vasculature, yet over time there are notable vessel differences in contralateral and ipsilateral hemispheres. Sex specific differences in BBB leakage coupled with vascular measures suggest early recovery is not sustained long-term.
Vepoloxamer Preserves Cerebral Microvascular Integrity and Blood Flow After Traumatic Brain Injury in Rats
Dr. Liang Chen1, Dr. Ye Xiong1, Dr. Michael Chopp2,3, Dr. Guangliang Ding2, Dr. Lian Li2, Dr. Zheng Gang Zhang2, Dr. Haiyan Pang1, Dr. Xing Wang1, Dr. Quan Jiang2,
1Department of Neurosurgery, Henry Ford Health, Detroit, United States, 2Department of Neurology, Henry Ford Health, Detroit, United States, 3Department of Physics, Oakland University, Rochester, United States
Previous studies show that Vepoloxamer promotes functional recovery in TBI rats. This study determined whether Vepoloxamer restores hemostatic regulation, improves cerebral vascular patency, and preserves vascular integrity after TBI. Young male Wistar rats subjected to moderate TBI were randomly treated with saline or Vepoloxamer (300 mg/kg, IV, 2 h post-injury). Cerebral blood flow (CBF) and vascular permeability (Ki) were assessed by MRI (24 h, 1 week, and 6 weeks post-TBI). Platelet dysfunction markers (platelet factor 4 [PF4], plasma von Willebrand factor [vWF]), and coagulation/fibrinolytic markers (tissue factor [TF], thrombomodulin [TM], D-dimer) were quantified by ELISA (3 h and 26 h post-injury). Cerebral vascular perfusion was assessed at 6 weeks using intravenous FITC-dextran. Vascular integrity was examined by Western blot analysis of tight junction proteins (zonula occludens 1 [ZO-1], claudin-5 [CLDN5], and occludin [OCLN]) and immunohistochemical assessment of matrix metalloproteinase-9 (MMP-9) levels and fibrin deposition at acute (3 h, 26 h) and chronic (35 days) stages. Data were analyzed using ANOVA followed by post hoc Tukey’s tests (P < 0.05). MRI showed that Vepoloxamer restored CBF to pre-TBI levels by 1 week. Vepoloxamer increased extrinsic coagulation and fibrinolysis at 3 h post-injury followed by normalization of coagulation activity and reduced endothelial injury at 26 h. At 6 weeks, Vepoloxamer significantly increased FITC-dextran vascular perfusion in the dentate gyrus, increased CLDN5 expression, partially preserved OCLN levels, and reduced extravascular fibrin deposition vs saline treatment. These results indicate that Vepoloxamer mitigates TBI-induced microvascular pathology and may improve long-term functional recovery after TBI.
When Endocrine and Cognitive Sequelae Overlap: Differentiating Hypopituitarism from Postconcussional Syndrome After Traumatic Brain Injury
1Houston Methodist Hospital, Houston, United States, 2Estacio de Sa University, Rio de Janeiro, Brazil, 3University of Sao Paulo, Sao Paulo, Brazil, 4Hospital Alemao Oswaldo Cruz, Sao Paulo, Brazil, 5University of Miami, Miami, United States, 6UT Health Houston, Houston, United States
Introduction: Traumatic brain injury is one of the significant causes of disability affecting individuals. Hypopituitarism can occur in the acute or chronic phase post-TBI. There is some degree of overlap between the hypopituitarism symptoms and the postconcussional syndrome. This study aims to compare the association of those symptoms with both conditions following TBI.
Methods: This study used TriNetX data from January 1, 2010, to August 13, 2024, to identify adult patients with TBI. The Hypopituitarism post-TBI cohort included patients with a first diagnosis of hypopituitarism within one year after TBI, while the Postconcussional syndrome cohort included patients diagnosed with postconcussional syndrome during the same timeframe. One-to-one PSM was performed for demographics, comorbidities, cranial lesions, mechanism of injury, laboratory, and medication use to balance cohorts. Patients with preexisting symptoms were excluded. Outcomes were assessed within one year of TBI.
Results: A total of 77,320 TBI patients were identified (53.8% female, 41.3% male, 4.9% unspecified). The Hypopituitarism post-TBI cohort included 1,415 patients (1.8%). After PSM, each cohort contained 1,414 patients. Compared with the Postconcussional syndrome cohort, Hypopituitarism post-TBI patients had higher rates of overweight or obesity (OR 1.43, 95% CI 1.00–2.04; p=0.048) and fatigue (OR 1.85, 95% CI 1.31–2.62; p<0.001). In contrast, cognitive deficits were more frequent in the Postconcussional syndrome cohort (OR 0.37, 95% CI 0.23–0.60; p<0.001).
Conclusion: Our findings suggest that patients with post-TBI hypopituitarism were more likely to exhibit weight gain and fatigue, whereas cognitive deficits were more strongly associated with postconcussional syndrome. Further prospective studies are warranted.
When Protocols Collide: Reconciling Damage Control Resuscitation and Cerebral Perfusion Pressure Targets in Polytrauma Patients with Concurrent Traumatic Brain Injury
1Department of Critical Care Medicine, Shuang Ho Hospital, New Taipei City, Taiwan, 2Department of Neurosurgery, Shuang Ho Hospital, New Taipei City, Taiwan
Background and Objectives: Damage control resuscitation (DCR) and traumatic brain injury (TBI) management represent two evidence-based paradigms that become directly contradictory in the polytrauma patient with concurrent hemorrhagic shock. DCR advocates permissive hypotension (MAP ∼50 mmHg) to limit coagulopathy prior to definitive hemorrhage control, while Brain Trauma Foundation guidelines mandate cerebral perfusion pressure (CPP) ≥ 60–70 mmHg to prevent secondary brain injury — targets that are physiologically irreconcilable when intracranial pressure is elevated. This review examines the evidence underlying this conflict and proposes a pragmatic clinical decision framework for the surgical ICU setting.
Methods: A narrative review of DCR and TBI resuscitation literature was conducted, with focused analysis of studies addressing concurrent hemorrhagic shock and TBI, secondary brain injury from hypotension, and vasopressor use in active hemorrhage.
Results: Major DCR trials systematically excluded significant TBI, and BTF guidelines were derived predominantly from isolated neurotrauma cohorts. Observational evidence consistently identifies hypotension as the most injurious secondary insult in TBI, even during brief resuscitation windows. No prospective trial directly addresses the combined management of DCR and TBI. Individualized MAP flooring using clinical ICP surrogates, prioritization of hemorrhage control speed, and judicious early vasopressor use emerge as reconciling strategies.
Conclusion: The DCR-TBI conflict represents a critical evidence gap in polytrauma management. A risk-stratified, time-sensitive framework — anchored by rapid hemorrhage control and clinical ICP estimation — offers a practical approach pending prospective validation.
White Matter Microstructural Characteristics Associated with Persistent Symptoms, Cognitive Impairment and Disability after Acute Traumatic Brain Injury: A TRACK-TBI Study
1University of California San Francisco, San Francisco, United States, 2University of Washington, Seattle, United States, 3Harvard Medical School, Boston, United States, 4Medical College of Wisconsin, Milwaukee, United States, 5Baylor College of Medicine, Houston, United States, 6University of California San Diego, San Diego, United States, 7University of Pennsylvania, Philadelphia, United States, 8University of Pittsburgh Medical Center, Pittsburgh, United States
To leverage standardized diffusion MRI and advanced image analysis in a multicenter longitudinal TBI cohort to characterize post-injury white matter (WM) microstructural evolution and examine associations between early diffusion metrics and persistent symptoms, cognitive impairment, and disability, this study acquired multishell dMRI from 331 acute TBI patients (ages 17-85) from 7 Level-1 trauma centers participating in the TRACK-TBI Phase 2 MRI study at 2 weeks and 6 months post-injury, and 49 demographically matched controls at comparable intervals. Data underwent artifact correction, denoising, retrospective multisite harmonization using rotationally invariant spherical harmonics (RISH), and DTI and NODDI modeling. Clinical outcomes include GOSE for disability, RPQ for symptoms, and WAIS-PSI for processing speed at 3 and 6 months post-injury.
RISH harmonization mitigated inter-site variability in diffusion metrics. Widespread longitudinal WM changes were observed in patients including decreased FA and NDI and increased diffusivities, most prominently in the corpus callosum, internal capsules, and association tracts. Brainstem and cerebellar tracts showed declining FA with trends toward increased NDI. Patients demonstrated higher NDI and FISO in brainstem and cerebellar WM than controls. Adjusting for clinical and demographic covariates, 2-week diffusion metrics in the corpus callosum, brainstem, and cerebellum predicted GOSE, RPQ, and WAIS-PSI outcomes.
Standardized multishell dMRI with advanced preprocessing, harmonization, and analyses enables reproducible multicenter DTI and NODDI, including previously understudied infratentorial WM. Early diffusion abnormalities independently predicted long-term disability, symptoms, and cognition, supporting advanced dMRI processing and modeling for TBI prognosis in research, experimental trials and clinical practice, with NODDI complementing DTI for prognostication.
Whole-Blood Point-of-Care Biomarkers and Head Computerized Tomography Use among Acute Mild Traumatic Brain Injury Patients: A POINT-mTBI Study
1Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, United States, 2Department of Emergency Medicine, University of Wisconsin, Madison, WI, Madison, United States, 3Department of Emergency Medicine, University of Michigan, Ann Arbor, United States, 4Department of Neurology, Medical College of Wisconsin, Milwaukee, United States
Many head computed tomography (CT) scans ordered for mild traumatic brain injury (mTBI) in the emergency department (ED) may be avoidable, generating excess radiation exposure and healthcare costs. In 2024, the Food and Drug Administration (FDA) approved the whole blood Abbott i-STAT TBI Test to rule out CT evaluation for acute traumatic intracranial lesions in mTBI. We investigated i-STAT TBI test positivity among CT-negative mTBI patients (GCS 13-15) enrolled from a Level 1 trauma center ED. Whole blood glial fibrillary acidic protein (GFAP) and ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) were measured using the i-STAT handheld point-of-care device within 12 hours postinjury. FDA-approved cut-offs for GFAP (<65 pg/mL) and UCH-L1 (<360 pg/mL), cleared for use within 24 hours of injury for ruling out CT-detectable acute traumatic intracranial lesions, were used to classify participants as ‘No CT Indicated’ or ‘CT Indicated’. Injury signs, symptoms (Rivermead Post-Concussion Symptoms Questionnaire [RPQ]), and cognition (Standardized Assessment of Concussion [SAC]) were compared between groups. Of 46 CT-negative patients enrolled with arrival GCS 15, 27 (59%) were ‘No CT Indicated’ and 19 (41%) were ‘CT Indicated.’ ‘CT Indicated’ patients were more likely to have loss of consciousness (15/19[79%] vs. 13/27[48%], p=0.033) but reported fewer RPQ symptoms (median[IQR]= 8[4,14] vs. 18[11,23], p=0.023). Groups did not differ in amnesia, altered mental status, or cognition. These results demonstrate that the whole blood testing of GFAP and UCH-L1 using the Abbott i-STAT point-of-care device could reduce avoidable CT scans in more than half of patients presenting to the ED with mTBI.
Why Traumatic Brain Injury Goes Undiagnosed: Diagnostic Patterns Based on Demographics, Injury Factors, and Clinical Presentation Across Seven Emergency Departments
1Medical College of Wisconsin, Milwaukee, United States
To understand why traumatic brain injury (TBI) is underidentified in emergency departments (EDs), it’s important to learn which factors lead to its diagnosis compared to common alternatives (“head injury”). Utilizing the American Congress of Rehabilitation Medicine’s (ACRM) 2023 diagnostic criteria of mTBI, we performed retrospective chart review on 490 adults assessed across seven EDs (3 hospital-based and 4 freestanding). Binary logistic regression was used to characterize the degree to which demographic, injury, and clinically documented ACRM criteria predicted receiving a TBI versus head injury diagnosis. Variables selected for a multivariable model through backwards selection were age, chief complaint, ED type, injury timing, head trauma evidence, ACRM Criterion 2 met, dizziness, balance problems, photophobia, and ACRM mTBI diagnosis met. This model showed odds of a TBI diagnosis were higher with presentation greater than 24 hours post-injury (OR=2.4); chief complaints of assault, motor vehicle collision, or a TBI symptom (versus head injury, ORs=2.6-6.6); evaluation at a Level I Trauma Center (versus freestanding ED, OR=2.6); documentation of dizziness (OR=2.9) or photophobia (OR=5.6); and when overall ACRM diagnostic criteria for mTBI were met (OR=8.9). Diagnosis was less likely if ACRM Criterion 2 (e.g., unconsciousness/amnesia) was met (OR=0.2) or if there was observable head trauma evidence (OR=0.3). The multivariable model demonstrated excellent discrimination, with an area under the receiver operating characteristic curve (AUC) of 0.83. These findings highlight the complexity in clinical decision making and suggest that further investigation will improve our understanding of ED-based clinical decisions about TBI.