Update June 2017

Acquired lymphedema is a cancer sequela and a global health problem currently lacking pharmacologic therapy. We have previously demonstrated that ketoprofen, an anti-inflammatory agent with dual 5-lipoxygenase and cyclooxygenase inhibitory properties, effectively reverses histopathology in experimental lymphedema. We show that the therapeutic benefit of ketoprofen is specifically attributable to its inhibition of the 5-lipoxygenase metabolite leukotriene B4 (LTB4). LTB4 antagonism reversed edema, improved lymphatic function, and restored lymphatic architecture in the murine tail model of lymphedema. In vitro, LTB4 was functionally bimodal: Lower LTB4 concentrations promoted human lymphatic endothelial cell sprouting and growth, but higher concentrations inhibited lymphangiogenesis and induced apoptosis. During lymphedema progression, lymphatic fluid LTB4 concentrations rose from initial prolymphangiogenic concentrations into an antilymphangiogenic range. LTB4 biosynthesis was similarly elevated in lymphedema patients. Low concentrations of LTB4 stimulated, whereas high concentrations of LTB4 inhibited, vascular endothelial growth factor receptor 3 and Notch pathways in cultured human lymphatic endothelial cells. Lymphatic-specific Notch1-/- mice were refractory to the beneficial effects of LTB4 antagonism, suggesting that LTB4 suppression of Notch signaling is an important mechanism in disease maintenance. In summary, we found that LTB4 was harmful to lymphatic repair at the concentrations observed in established disease. Our findings suggest that LTB4 is a promising drug target for the treatment of acquired lymphedema.

The overall premise of this review is that cerebrospinal fluid (CSF) is transported within a dedicated peri-vascular network facilitating metabolic waste clearance from the central nervous system while we sleep. The anatomical profile of the network is complex and has been defined as a peri-arterial CSF influx pathway and peri-venous clearance routes, which are functionally coupled by interstitial bulk flow supported by astrocytic aquaporin 4 water channels. The role of the newly discovered system in the brain is equivalent to the lymphatic system present in other body organs and has been termed the “glymphatic pathway” or “(g)lymphatics” because of its dependence on glial cells. We will discuss and review the general anatomy and physiology of CSF from the perspective of the glymphatic pathway, a discovery which has greatly improved our understanding of key factors that control removal of metabolic waste products from the central nervous system in health and disease and identifies an additional purpose for sleep. A brief historical and factual description of CSF production and transport will precede the ensuing discussion of the glymphatic system along with a discussion of its clinical implications.

Mural cells of the vertebrate brain maintain vascular integrity and function, play roles in stroke and are involved in maintenance of neural stem cells. However, the origins, diversity and roles of mural cells remain to be fully understood. Using transgenic zebrafish, we identified a population of isolated mural lymphatic endothelial cells surrounding meningeal blood vessels. These meningeal mural lymphatic endothelial cells (muLECs) express lymphatic endothelial cell markers and form by sprouting from blood vessels. In larvae, muLECs develop from a lymphatic endothelial loop in the midbrain into a dispersed, nonlumenized mural lineage. muLEC development requires normal signaling through the Vegfc-Vegfd-Ccbe1-Vegfr3 pathway. Mature muLECs produce vascular growth factors and accumulate low-density lipoproteins from the bloodstream. We find that muLECs are essential for normal meningeal vascularization. Together, these data identify an unexpected lymphatic lineage and developmental mechanism necessary for establishing normal meningeal blood vasculature.

Lymphatic vasculature regulates fluid homeostasis by returning interstitial fluid to blood circulation. Lymphatic endothelial cells (LECs) are the building blocks of the entire lymphatic vasculature. LECs originate as a homogeneous population of cells predominantly from the embryonic veins and undergo stepwise morphogenesis to become the lymphatic capillaries, collecting vessels or valves. The molecular mechanisms underlying the morphogenesis of the lymphatic vasculature remain to be fully understood. Here we show that canonical Wnt/beta-catenin signaling is necessary for lymphatic vascular morphogenesis. Lymphatic vascular-specific ablation of beta-catenin in mice prevents the formation of lymphatic and lymphovenous valves. Additionally, lymphatic vessel patterning is defective in these mice, with abnormal recruitment of mural cells. We found that oscillatory shear stress (OSS), which promotes lymphatic vessel maturation, triggers Wnt/beta-catenin signaling in LECs. In turn, Wnt/beta-catenin signaling controls the expression of several molecules, including the lymphedema-associated transcription factor FOXC2. Importantly, FOXC2 completely rescues the lymphatic vessel patterning defects in mice lacking beta-catenin. Thus, our work reveals that mechanical stimulation is a critical regulator of lymphatic vascular development via activation of Wnt/beta-catenin signaling and, in turn, FOXC2.

OBJECTIVE: Mesenteric lymphatic vessel pumping, important to propel lymph and immune cells from the intestinal interstitium to the mesenteric lymph nodes, is compromised during intestinal inflammation. The objective of this study was to test the hypothesis that the pro-inflammatory cytokine TNF-alpha, is a significant contributor to the inflammation-induced lymphatic contractile dysfunction, and to determine its mode of action. METHODS: Contractile parameters were obtained from isolated rat mesenteric lymphatic vessels mounted on a pressure myograph after 24-hours incubation with or without TNF-alpha. Various inhibitors were administered, and quantitative real-time PCR, Western blotting, and immunofluorescence confocal imaging were applied to characterize the mechanisms involved in TNF-alpha actions. RESULTS: Vessel contraction frequency was significantly decreased after TNF-alpha treatment and could be restored by selective inhibition of NF-small ka, CyrillicB, iNOS, guanylate cyclase, and ATP-sensitive K+ channels. We further demonstrated that NF-small ka, CyrillicB inhibition also suppressed the significant increase in iNOS mRNA observed in TNF-alpha-treated lymphatic vessels and that TNF-alpha treatment favored the nuclear translocation of the p65 NF-kappaB subunit. CONCLUSIONS: These findings suggest that TNF-alpha decreases mesenteric lymphatic contractility by activating the NF-kappaB-iNOS signaling pathway. This mechanism could contribute to the alteration of lymphatic pumping reported in intestinal inflammation.

The major function of the lymphatic system is to drain interstitial fluid from tissue. Functional drainage causes increased fluid flow that triggers lymphatic expansion, which is conceptually similar to hypoxia-triggered angiogenesis. Here, we have identified a mechanotransduction pathway that translates laminar flow-induced shear stress to activation of lymphatic sprouting. While low-rate laminar flow commonly induces the classic shear stress responses in blood endothelial cells and lymphatic endothelial cells (LECs), only LECs display reduced Notch activity and increased sprouting capacity. In response to flow, the plasma membrane calcium channel ORAI1 mediates calcium influx in LECs and activates calmodulin to facilitate a physical interaction between Kruppel-like factor 2 (KLF2), the major regulator of shear responses, and PROX1, the master regulator of lymphatic development. The PROX1/KLF2 complex upregulates the expression of DTX1 and DTX3L. DTX1 and DTX3L, functioning as a heterodimeric Notch E3 ligase, concertedly downregulate NOTCH1 activity and enhance lymphatic sprouting. Notably, overexpression of the calcium reporter GCaMP3 unexpectedly inhibited lymphatic sprouting, presumably by disturbing calcium signaling. Endothelial-specific knockouts of Orai1 and Klf2 also markedly impaired lymphatic sprouting. Moreover, Dtx3l loss of function led to defective lymphatic sprouting, while Dtx3l gain of function rescued impaired sprouting in Orai1 KO embryos. Together, the data reveal a molecular mechanism underlying laminar flow-induced lymphatic sprouting.

Cardiac lymphatic vasculature undergoes substantial expansion in response to myocardial infarction (MI). However, there is limited information on the cellular mechanisms mediating post-MI lymphangiogenesis and accompanying fibrosis in the infarcted adult heart. Using a mouse model of permanent coronary artery ligation, we examined spatiotemporal changes in the expression of lymphendothelial and mesenchymal markers in the acutely and chronically infarcted myocardium. We found that at the time of wound granulation, a three-fold increase in the frequency of podoplanin-labeled cells occurred in the infarcted hearts compared to non-operated and sham-operated counterparts. Podoplanin immunoreactivity detected LYVE-1-positive lymphatic vessels, as well as masses of LYVE-1-negative cells dispersed between myocytes, predominantly in the vicinity of the infarcted region. Podoplanin-carrying populations displayed a mesenchymal progenitor marker PDGFRalpha, and intermittently expressed Prox-1, a master regulator of the lymphatic endothelial fate. At the stages of scar formation and maturation, concomitantly with the enlargement of lymphatic network in the injured myocardium, the podoplanin-rich LYVE-1-negative multicellular assemblies were apparent in the fibrotic area, aligned with extracellular matrix deposits, or located in immediate proximity to activated blood vessels with high VEGFR-2 content. Of note, these podoplanin-containing cells acquired the expression of PDGFRbeta or a hematoendothelial epitope CD34. Although Prox-1 labeling was abundant in the area affected by MI, the podoplanin-presenting cells were not consistently Prox-1-positive. The concordance of podoplanin with VEGFR-3 similarly varied. Thus, our data reveal previously unknown phenotypic and structural heterogeneity within the podoplanin-positive cell compartment in the infarcted heart, and suggest an alternate ability of podoplanin-presenting cardiac cells to generate lymphatic endothelium and pro-fibrotic cells, contributing to scar development.

Lymphangiogenesis, the formation of new lymphatic vessels, occurs in primary tumors and in draining lymph nodes leading to pre-metastatic niche formation. Reliable in vivo models are becoming instrumental for investigating alterations occurring in lymph nodes before tumor cell arrival. In this study, we demonstrate that B16F10 melanoma cell encapsulation in a biomaterial, and implantation in the mouse ear, prevents their rapid lymphatic spread observed when cells are directly injected in the ear. Vascular remodeling in lymph nodes was detected two weeks after sponge implantation, while their colonization by tumor cells occurred two weeks later. In this model, a huge lymphangiogenic response was induced in primary tumors and in pre-metastatic and metastatic lymph nodes. In control lymph nodes, lymphatic vessels were confined to the cortex. In contrast, an enlargement and expansion of lymphatic vessels towards paracortical and medullar areas occurred in pre-metastatic lymph nodes. We designed an original computerized-assisted quantification method to examine the lymphatic vessel structure and the spatial distribution. This new reliable and accurate model is suitable for in vivo studies of lymphangiogenesis, holds promise for unraveling the mechanisms underlying lymphatic metastases and pre-metastatic niche formation in lymph nodes, and will provide new tools for drug testing.

This protocol describes a unique in vitro method for the generation of a 3D human lymphatic network within native connective tissue devoid of any exogenous material such as scaffolds or growth factors. In this five-stage protocol, human lymphatic endothelial cells (LECs) cocultured with dermal fibroblasts spontaneously organize into a stable 3D lymphatic capillary network. Stage 1 involves the isolation of primary fibroblasts and LECs from human skin. Fibroblasts are then cultured to produce connective tissue rich in extracellular matrix (stage 2), onto which LECs are seeded to form a network (stage 3). After stacking of tissue layers and tissue maturation at the air-liquid interface (stage 4), the 3D construct containing the lymphatic microvascular network can be analyzed by microscopy (stage 5). Lymphatic vasculature generated by this approach exhibits the major cellular and ultrastructural features of native in vivo human dermal lymphatic microvasculature and is stable over many weeks. The protocol for generating a 3D construct takes 6 weeks to complete, and it requires experience in cell culture techniques. The system described here offers a unique opportunity to study the mechanisms underlying lymphatic vessel formation, remodeling and function in a human cell context.

BACKGROUND: Lymphoedema represents the cardinal manifestation of lymphatic dysfunction and is associated with expansion of the adipose tissue in the affected limb. In mice, high-fat diet (HFD)-induced obesity was associated with impaired collecting lymphatic vessel function, and adiposity aggravated surgery-induced lymphoedema in a mouse model. The aim of the current study was to investigate whether adiposity is necessary to impair lymphatic function or whether increased lipid exposure alone might be sufficient in a surgical lymphoedema model. METHODS: To investigate the role of increased lipid exposure in lymphoedema development we used a well-established mouse tail lymphoedema model. Female mice were subjected to a short-term (6 weeks) HFD, without development of obesity, before surgical induction of lymphedema. Lymphoedema was followed over a period of 6 weeks measuring oedema, evaluating tissue histology and lymphatic vascular function. RESULTS: HFD increased baseline angiogenesis and average lymphatic vessel size in comparison to the chow control group. Upon induction of lymphedema, HFD-treated mice did not exhibit aggravated oedema and no morphological differences were observed in the blood and lymphatic vasculature. Importantly, the levels of fibro-adipose tissue deposition were comparable between the 2 groups and lymphatic vessel function was not impaired as a result of the HFD. Although the net immune cell infiltration was comparable, the HFD group displayed an increased infiltration of macrophages, which exhibited an M2 polarization phenotype. CONCLUSIONS: These results indicate that increased adiposity rather than dietary influences determines predisposition to or severity of lymphedema.

Secondary lymphedema is a common post-cancer treatment complication but the pathomechanisms underlying the disease remain unclear. Using a mouse-tail lymphedema model, we found an increase in local and systemic levels of the lymphangiogenic factor VEGF-C, and identified CD68+ macrophages as a cellular source. Surprisingly, overexpression of VEGF-C in a transgenic mouse model led to aggravation of lymphedema with increased immune cell infiltration and vascular leakage in comparison to wild-type littermates. Conversely, blockage of VEGF-C by overexpression of soluble VEGFR3 reduced edema development, diminishing inflammation and blood vascular leakage. Similar findings were obtained in a hind limb lymph node excision lymphedema model. Flow cytometry analyses and immunofluorescence stainings in lymphedematic tissue revealed that VEGFR3 expression was restricted to lymphatic endothelial cells. Our data suggest that endogenous VEGF-C causes blood vascular leakage and fluid influx into the tissue, thus actively contributing to edema formation. These data may provide the basis for future clinical therapeutic approaches.

BACKGROUND: Secondary lymphedema is often observed in postmalignancy treatment of the breast and the gynecologic organs, but effective therapies have not been established in chronic cases even with advanced physiologic operations. Currently, reconstructive surgery with novel approaches has been attempted. METHODS: The hindlimbs of 10-week-old male C57BL/6J mice, after 30-Gy x-irradiation, surgical lymph node dissection, and 5-mm gap creation, were divided into four groups, with vascularized lymph node transfer abdominal flap and 1.0 × 10 adipose-derived stem cells. Lymphatic flow assessment, a water-displacement plethysmometer paw volumetry test, tissue quantification of lymphatic vessels, and functional analysis of lymphatic vessels and nodes were performed. RESULTS: Photodynamic Eye images, using indocyanine green fluorescence, demonstrated immediate staining in subiliac lymph nodes, and linear pattern imaging of the proximal region was observed with the combined treatment of adipose-derived stem cells and vascularized lymph node transfer. Both percentage improvement and percentage deterioration with the combined treatment of adipose-derived stem cells and vascularized lymph node transfer were significantly better than with other treatments (p < 0.05). The numbers of lymphatic vessels with LYVE-1 immunoreactivity significantly increased in mice treated with adipose-derived stem cells (p < 0.05), and B16 melanoma cells were metastasized in groups treated with vascularized lymph node transfers by day 28. CONCLUSIONS: Adipose-derived stem cells increase the number of lymphatic vessels and vascularized lymph node transfers induce the lymphatic flow drainage to the circulatory system. Combined adipose-derived stem cell and vascularized lymph node transfer treatment in secondary lymphedema may effectively decrease edema volume and restore lymphatic function by lymphangiogenesis and the lymphatic-to-venous circulation route.

The maintenance of tissue homeostasis is indispensable for health. In particular, removal of toxic compounds from cells and organs is a vital process for the organism. The lymphatic vasculature works in order to ensure the efficient removal of tissue waste. Forbidden over the last decade when more attention was paid to the blood vasculature, studies on the lymphatic vasculature have gained momentum during the last couple of years. The lymphatic vasculature naturally runs parallel to the blood vasculature and their synergistic work is critical for maintaining tissue homeostasis. Diminished lymphatic function results in accumulation of body fluids in tissues and gives rise to edema. Recently, it became obvious that immune cells including myeloid cells and lymphocytes are able to interact with and control the development and function of the lymphatic vasculature. In this review, we will focus on the interaction between myeloid cells, including macrophages, monocytes, and dendritic cells, with lymphatic vessels.

Several studies have produced contradictory findings about the prognostic implications for inhibitor of apoptosis proteins (IAPs) in different types of cancer. Cellular inhibitor of apoptosis 2 (cIAP2/BIRC) is one of the most extensively characterized human IAPs. To date no studies have focused on the expression level of cIAP2 in human gallbladder cancer (GBC), and the mechanism of cIAP2 in GBC invasion and lymphangiogenesis remains unclear. Therefore, in the present study, cIAP2 expression in GBC was detected using qRT-PCR and immunohistochemistry, and the relationship between cIAP2 levels in cancer tissues and the clinicopathological characteristics of patients was analysed. The biological effect of cIAP2 in GBC cells was tested using the Cell Counting Kit-8 assay, transwell assays and the ability of human dermal lymphatic endothelial cells (HDLECs) to undergo tube formation. The role of cIAP2 in activating the NF-kappaB pathway was determined using a dual-luciferase reporter assay, immunofluorescence staining, Western blotting and ELISA. Finally, an animal model was used to further confirm the role of cIAP2 in lymphangiogenesis. We showed that cIAP2 expression was elevated in human GBC tissues and correlateed with a negative prognosis for patients. Moreover, cIAP2 was identified as a lymphangiogenic factor of GBC cells and thus promoted lymph node metastasis in GBC cells. Our study is the first to suggest that cIAP2 can promote GBC invasion and lymphangiogenesis by activating the NF-kappaB pathway. This article is protected by copyright. All rights reserved.

Trafficking of tissue dendritic cells (DCs) via lymph is critical for the generation of cellular immune responses in draining lymph nodes (LNs). In the current study we found that DCs docked to the basolateral surface of lymphatic vessels and transited to the lumen through hyaluronan-mediated interactions with the lymph-specific endothelial receptor LYVE-1, in dynamic transmigratory-cup-like structures. Furthermore, we show that targeted deletion of the gene Lyve1, antibody blockade or depletion of the DC hyaluronan coat not only delayed lymphatic trafficking of dermal DCs but also blunted their capacity to prime CD8+ T cell responses in skin-draining LNs. Our findings uncovered a previously unknown function for LYVE-1 and show that transit through the lymphatic network is initiated by the recognition of leukocyte-derived hyaluronan.

The lymphatic vascular system is a hierarchically organized complex network essential for tissue fluid homeostasis, immune trafficking, and absorption of dietary fats in the human body. Despite its importance, the assembly of the lymphatic network is still not fully understood. The zebrafish is a powerful model organism that enables study of lymphatic vessel development using high-resolution imaging and sophisticated genetic and experimental manipulation. Although several studies have described early lymphatic development in the fish, lymphatic development at later stages has not been completely elucidated. In this study, we generated a new Tg(mrc1a:egfp)y251 transgenic zebrafish using a Mannose receptor C type 1 (MRC1) promoter that drives strong EGFP expression in lymphatic vessels at all stages of development and in adult zebrafish. We used this line to describe the assembly of the major vessels of the trunk lymphatic vascular network, including the later-developing collateral cardinal lymphatics, spinal lymphatic, superficial lateral lymphatics, and superficial intersegmental lymphatics. Our results show that major trunk lymphatic vessels are conserved in the zebrafish, and provide a thorough and complete description of trunk lymphatic vessel assembly.

RATIONALE: Lymphatic vessel formation and function constitutes a physiologically and pathophysiologically important process, but its genetic control is not well understood. OBJECTIVE: Here, we identify the secreted Polydom/Svep1 protein as essential for the formation of the lymphatic vasculature. We analyzed mutants in mice and zebrafish to gain insight into the role of Polydom/Svep1 in the lymphangiogenic process. METHODS AND RESULTS: Phenotypic analysis of zebrafish polydom/svep1 mutants showed a decrease in venous and lymphovenous sprouting, which leads to an increased number of intersegmental arteries. A reduced number of primordial lymphatic cells populated the horizontal myoseptum region but failed to migrate dorsally or ventrally, resulting in severe reduction of the lymphatic trunk vasculature. Corresponding mutants in the mouse Polydom/Svep1 gene showed normal egression of Prox-1+ cells from the cardinal vein at E10.5, but at E12.5, the tight association between the cardinal vein and lymphatic endothelial cells at the first lymphovenous contact site was abnormal. Furthermore, mesenteric lymphatic structures at E18.5 failed to undergo remodeling events in mutants and lacked lymphatic valves. In both fish and mouse embryos, the expression of the gene suggests a nonendothelial and noncell autonomous mechanism. CONCLUSIONS: Our data identify zebrafish and mouse Polydom/Svep1 as essential extracellular factors for lymphangiogenesis. Expression of the respective genes by mesenchymal cells in intimate proximity with venous and lymphatic endothelial cells is required for sprouting and migratory events in zebrafish and for remodeling events of the lymphatic intraluminal valves in mouse embryos.

BACKGROUND: Although lymphedematous skin exhibits delayed wound healing, little is known about lymph drainage during wound healing. We investigated the wound healing process in the presence of lymphatic dysfunction. METHODS AND RESULTS: The right inguinal lymph nodes (iLNs) and the surrounding tissue were excised in each mouse (the operation side), and a sham operation was performed in the left hindlimb (the control side). The next day, full-thickness wounds were made on both hindlimbs. The right hindlimb exhibited acute edema until day 3; however, it started to improve after day 4, and the wound area and epithelialization ratio were similar on both sides. Indocyanine green (ICG) was injected into both hindlimbs to observe lymph flow. On the operation side, ICG leaked out of the surgical site or remained at the injection site until day 2. Some lymph flow toward the existing lymph vessels was seen on day 3, and on day 10, lymph flow toward the axial LNs was detected on the operation side in all mice. On the operation side, the number of dermal lymph vessels was significantly increased on days 3 and 15. The dermal lymph vessel area of the peripheral wound was significantly smaller on the operation side. CONCLUSIONS: In a hindlimb lymphedema mouse model, lymph transiently accumulated in subcutaneous tissue, and then was gradually absorbed by the existing lymph vessels. The increase in the number of lymph vessels contributes to lymph drainage during wound healing. Acute lymphedema because of transient lymphatic dysfunction has little effect on wound healing.

PURPOSE: To investigate the feasibility of nintedanib, a novel triple angiokinase inhibitor, for inhibiting lymphatic endothelial cell (LEC)-induced lymphangiogenesis in vitro and inflammatory corneal lymphangiogenesis in vivo. MATERIALS AND METHODS: Methylthiazolyldiphenyl-tetrazolium bromide (MTT) test, transwell system, and tube-formation assay were used to evaluate the effects of nintedanib on the proliferation, migration, and tube formation of LECs stimulated by vascular endothelial growth factor-C (VEGF-C), basic fibroblast growth factor (bFGF), or platelet-derived growth factor-BB (PDGF-BB). The murine model of suture-induced corneal neovascularization was used to assess the anti-hemangiogenic and anti-lymphangiogenic effects of nintedanib via systemic and topical applications. Corneal flatmounts were stained with lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1) and CD31, and the areas of involved blood and lymph vessels were analyzed morphometrically. Corneal cryosections were stained with F4/80 to evaluate inflammatory cell recruitment. RESULTS: We observed a significant enhanced effect of LEC proliferation, migration, and tube formation with the administration of VEGF-C, PDGF-BB, and bFGF, respectively, which was diminished by nintedanib. Both topical and systemic applications of nintedanib inhibited suture-induced hemangiogenesis and lymphangiogenesis in the murine cornea. A reduction in F4/80+ cell infiltration was observed at day 14 after corneal suture for both systemic and topical applications of nintedanib. In comparison with controls, 61% of F4/80+ cell recruitment was inhibited via the systemic application of nintedanib, while 49% of F4/80+ cell recruitment was inhibited with the topical application of nintedanib. CONCLUSION: Nintedanib was shown to inhibit in vitro lymphangiogenesis stimulated by VEGF-C, bFGF, and PDGF-BB. Applied topically or systemically, it effectively inhibited corneal hemangiogenesis and lymphangiogenesis, accompanied by reduced inflammatory cell recruitment, which represents a new promising treatment for graft rejection after penetrating keratoplasty.

Kallistatin has been recognized as an endogenous angiogenic inhibitor. However, its effects on lymphatic endothelial cells and lymphangiogenesis remain poorly understood. Lymphangiogenesis is involved in tumor metastasis via the lymphatic vasculature in various types of tumors. The aim of this study was to investigate the effects of kallistatin on lymphangiogenesis and the mechanism of action involved. Treatment with kallistatin recombinant protein or overexpression of kallistatin inhibited the proliferation, migration and tube formation of human lymphatic endothelial cells (hLECs), and induced apoptosis of hLECs. Furthermore, our results showed that the lymphatic vessel density (LVD) was reduced in lung and stomach sections from kallistatin-overexpressing transgenic mice. Treatment with kallistatin recombinant protein decreased the LVD in the implanted gastric xenograft tumors of nude mice. To the best of our knowledge, the present study is the first to demonstrate that kallistatin possesses anti-lymphangiogenic activity in vitro and in vivo. Moreover, kallistatin inhibited proliferation and migration of hLECs by reducing the phosphorylation of ERK and Akt, respectively. These findings suggested that kallistatin may be a promising agent that could be used to suppress cancer metastasis by inhibiting both angiogenesis and lymphangiogenesis.

Purpose: Netrin-4, a secreted protein, is found in the basement membrane of blood vessels and acts as a key regulator of angiogenesis. Here we investigated the role of Netrin-4 in the mouse-model of suture-induced corneal hem- and lymphangiogenesis. Methods: Corneal hem- and lymphangiogenesis were induced in Netrin-4-deficient (Ntn4-/-) and wild-type (WT) mice by placing three 11-0 nylon sutures intrastromally. Fourteen days after suturing, the vascularized area was analyzed via corneal flat mount immunohistochemistry. Messenger RNA levels for VEGF-A, VEGF-C, Lyve-1, Netrin-4, Unc5H2, “deleted in colon cancer” receptor, and Neogenin in treated and nontreated mouse corneas, cultured human corneal keratocytes (HCK) and epithelial cells (HCEC+HCET) were analyzed by quantitative PCR. Results: In wild-type mice, Netrin-4 mRNA expression in the cornea decreased in growing corneal neovascularization after suturing. Correspondingly, Ntn4-/- mice showed an increased vascularized area compared to that in WT mice. Expression of VEGF-A mRNA was higher in Ntn4-/- versus WT mice. There was no Netrin-4 expression in lymphatic vessels and the area of lymphatic vascularization did not differ between Ntn4-/- and WT mice, nor did expression of VEGF-C and Lyve-1 mRNA. Human corneal epithelial cells showed mainly Netrin-4 mRNA expression, which increased after stimulation, while HCK demonstrated Unc5H2 mRNA expression. Expression of VEGF-A, Netrin-4, Unc5H2, and Neogenin mRNA in HCEC and HCK did not differ significantly between the serum-free condition and VEGF-A or Netrin-4 stimulation. Conclusions: Absence of Netrin-4 increased corneal hemangiogenesis but not lymphangiogenesis in the mouse-model of suture-induced neovascularization. Netrin-4 acted as an antiangiogenic factor in the cornea, with which the healthy cornea is enriched via its expression by corneal epithelial cells.

Mesenchymal stem cells (MSCs) are multipotent stromal cells with immunomodulatory properties. They have emerged as a very promising treatment for autoimmunity and inflammatory diseases such as rheumatoid arthritis. Previous studies have demonstrated that MSCs, administered systemically, migrate to lymphoid tissues associated with the inflammatory site where functional MSC-induced immune cells with a regulatory phenotype were increased mediating the immunomodulatory effects of MSCs. These results suggest that homing of MSCs to the lymphatic system plays an important role in the mechanism of action of MSCs in vivo. Thus, we hypothesized that direct intralymphatic (IL) (also referred as intranodal) administration of MSCs could be an alternative and effective route of administration for MSC-based therapy. Here, we report the feasibility and efficacy of the IL administration of human expanded adipose mesenchymal stem cells (eASCs) in a mouse model of collagen-induced arthritis (CIA). IL administration of eASCs attenuated the severity and progression of arthritis, reduced bone destruction and increased the levels of regulatory T cells (CD25+Foxp3+CD4+ cells) and Tr1 cells (IL10+CD4+), in spleen and draining lymph nodes. Taken together, these results indicate that IL administration of eASCs is very effective in modulating established CIA and may represent an alternative treatment modality for cell therapy with eASCs.

Angiogenesis is important for normal development as well as for tumour growth. However, the molecular and cellular mechanisms underlying angiogenesis are not fully understood, partly because of the lack of a good animal model for imaging. Here, we report the generation of a novel transgenic (Tg) mouse that expresses a bioluminescent reporter protein, Nano-lantern, under the control of Fetal liver kinase 1 (Flk1). Flk1-Nano-lantern BAC Tg mice recapitulated endogenous Flk1 expression in endothelial cells and lymphatic endothelial cells during development and tumour growth. Importantly, bioluminescence imaging of endothelial cells from the aortic rings of Flk1-Nano-lantern BAC Tg mice enabled us to observe endothelial sprouting for 18 hr without any detectable phototoxicity. Furthermore, Flk1-Nano-lantern BAC Tg mice achieved time-lapse luminescence imaging of tumour angiogenesis in freely moving mice with implanted tumours. Thus, this transgenic mouse line contributes a unique model to study angiogenesis within both physiological and pathological contexts.

PURPOSE OF REVIEW: The central nervous system (CNS) has a unique relationship with the immune system. This review highlights the distinct roles of lymphatic vessels and endothelial cells in the interface between CNS and immune cells and invites to revisit the concept of CNS immune privilege. RECENT FINDINGS: T cells can follow several routes to penetrate the CNS parenchyma but may also benefit, together with antigen-loaded presenting cells, from the newly described lymphatic network to exit the CNS. CNS endothelial cells (EC) critically positioned at the interface between circulating immune cells and the CNS regulate the multistep cascade for immune cell trafficking into the CNS. They can also be considered as semiprofessional antigen-presenting cells through their ability to present antigens to T cells and to regulate their activation through co-stimulatory and inhibitory molecules. SUMMARY: The lymphatic network linking the CNS to draining lymph nodes may contribute to the inflammatory reaction occurring in multiple sclerosis (MS). The abundance and strategic positioning of endothelial cells at the blood-brain barrier level most likely endow them with an important role in controlling local adaptive immune responses, rendering them potential therapeutic targets in neuro-inflammatory such as MS.

RATIONALE: Lymphatic vasculature constitutes a second vascular system essential for immune surveillance and tissue fluid homeostasis. Maturation of the hierarchical vascular structure, with a highly branched network of capillaries and ducts, is crucial for its function. Environmental cues mediate the remodeling process, but the mechanism that underlies this process is largely unknown. OBJECTIVE: Polydom (also called Svep1) is an extracellular matrix protein identified as a high-affinity ligand for integrin alpha9beta1. However, its physiological function is unclear. Here, we investigated the role of Polydom in lymphatic development. METHODS AND RESULTS: We generated Polydom-deficient mice. Polydom-/- mice showed severe edema and died immediately after birth because of respiratory failure. We found that although a primitive lymphatic plexus was formed, it failed to undergo remodeling in Polydom-/- embryos, including sprouting of new capillaries and formation of collecting lymphatic vessels. Impaired lymphatic development was also observed after knockdown/knockout of polydom in zebrafish. Polydom was deposited around lymphatic vessels, but secreted from surrounding mesenchymal cells. Expression of Foxc2 (forkhead box protein c2), a transcription factor involved in lymphatic remodeling, was decreased in Polydom-/- mice. Polydom bound to the lymphangiogenic factor Ang-2 (angiopoietin-2), which was found to upregulate Foxc2 expression in cultured lymphatic endothelial cells. Expressions of Tie1/Tie2 receptors for angiopoietins were also decreased in Polydom-/- mice. CONCLUSIONS: Polydom affects remodeling of lymphatic vessels in both mouse and zebrafish. Polydom deposited around lymphatic vessels seems to ensure Foxc2 upregulation in lymphatic endothelial cells, possibly via the Ang-2 and Tie1/Tie2 receptor system.

During plaque progression, inflammatory cells progressively accumulate in the adventitia, paralleled by an increased presence of leaky vasa vasorum. We here show that next to vasa vasorum, also the adventitial lymphatic capillary bed is expanding during plaque development in humans and mouse models of atherosclerosis. Furthermore, we investigated the role of lymphatics in atherosclerosis progression. Dissection of plaque draining lymph node and lymphatic vessel in atherosclerotic ApoE-/- mice aggravated plaque formation, which was accompanied by increased intimal and adventitial CD3+ T cell numbers. Likewise, inhibition of VEGF-C/D dependent lymphangiogenesis by AAV aided gene transfer of hVEGFR3-Ig fusion protein resulted in CD3+ T cell enrichment in plaque intima and adventitia. hVEGFR3-Ig gene transfer did not compromise adventitial lymphatic density, pointing to VEGF-C/D independent lymphangiogenesis. We were able to identify the CXCL12/CXCR4 axis, which has previously been shown to indirectly activate VEGFR3, as a likely pathway, in that its focal silencing attenuated lymphangiogenesis and augmented T cell presence. Taken together, our study not only shows profound, partly CXCL12/CXCR4 mediated, expansion of lymph capillaries in the adventitia of atherosclerotic plaque in humans and mice, but also is the first to attribute an important role of lymphatics in plaque T cell accumulation and development.

Chronic inflammatory diseases are associated with a persistent and enhanced response to environmental antigens. As an adaptive response to this exaggerated immune state, affected tissue typically develops tertiary lymphoid organs. Studies of Crohn disease (CD), a chronic inflammatory disease of the intestinal tract, report tertiary lymphoid organs present within the mucosal wall, along with other lymphatic diseases, such as lymphangiogenesis and obstructed lymphatic vessels. These observations suggest that downstream mesenteric lymphatic vessels and lymph drainage into mesenteric lymph nodes may be compromised. However, information is lacking on the morphologic features and functional status of mesenteric lymphatics in CD. Using confocal imaging, PCR, flow cytometry, and functional strategies, we addressed these questions in the established TNFDeltaARE mouse model of CD and found that this mouse model had many lymphatic abnormalities reminiscent of human CD. These abnormalities include intestinal lymphangiectasia, mesenteric lymph node lymphadenopathy, and lymphangiogenesis in both the mesentery and mucosa. Critically, TNFDeltaARE mice also present mesenteric tertiary lymphoid organs and have altered lymphatic transport of dendritic cells to mesenteric lymph nodes, two features likely to actively modulate immunity. Our findings provide key insights into lymphatic remodeling in the TNFDeltaARE mouse model. They shed light on the involvement of these lymphatic changes in immune dysfunctions observed in CD and suggest the lymphatic system as new target for therapeutic options.

Optical Coherence Tomography (OCT) imaging of living subjects offers increased depth of penetration while maintaining high spatial resolution when compared to other optical microscopy techniques. However, since most protein biomarkers do not exhibit inherent contrast detectable by OCT, exogenous contrast agents must be employed for imaging specific cellular biomarkers of interest. While a number of OCT contrast agents have been previously studied, demonstrations of molecular targeting with such agents in live animals have been historically challenging and notably limited in success. Here we demonstrate for the first time that microbeads (microBs) can be used as contrast agents to target cellular biomarkers in lymphatic vessels and can be detected by OCT using a phase variance algorithm. This molecular OCT method enables in vivo imaging of the expression profiles of lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1), a biomarker that plays crucial roles in inflammation and tumor metastasis. In vivo OCT imaging of LVYE-1 showed that the biomarker was significantly down-regulated during inflammation induced by acute contact hypersensitivity (CHS). Our work demonstrated a powerful molecular imaging tool that can be used for high resolution studies of lymphatic function and dynamics in models of inflammation, tumor development, and other lymphatic diseases.

A controversy over the transport of chyle and lymph started a few weeks after the publication of Pecquet's Experimenta Nova Anatomica. There are records of nearly seventy people who had an active interest in this matter. Three issues were discussed: the purpose of the liver and especially its haematopoietic function, the capacity of the thoracic duct to transport all chyle, and the purpose of the lymph vessels. The controversy over the use of the lacteals and the lymph vessels subsided about 20 years after the first publication of the new theories. In this contribution, we focused on the ideas of William Harvey, since his ideas were close to the real configuration of the lymphatic system, and on the peculiar anatomical set-up of Louis De Bils (ca 1624–1669), an obscure French-Flemish non-professional anatomist, who was the initiator of a heated controversy in the Netherlands with his original ideas.

Podoplanin is a mucin-type highly O-glycosylated glycoprotein identified in several somatyic cells: podocytes, alveolar epithelial cells, lymphatic endothelial cells, lymph node stromal fibroblastic reticular cells, osteocytes, odontoblasts, mesothelial cells, glia cells, and others. It has been reported that podoplanin-RhoA interaction induces cytoskeleton relaxation and cell process stretching in fibroblastic cells and osteocytes, and that podoplanin plays a critical role in type I alveolar cell differentiation. It appears that podoplanin plays a number of different roles in contributing to cell functioning and growth by signaling. However, little is known about the functions of podoplanin in the somatic cells of the adult organism because an absence of podoplanin is lethal at birth by the respiratory failure. In this report, we investigated the tooth germ development in podoplanin-knockout mice, and the dentin formation in podoplanin-conditional knockout mice having neural crest-derived cells with deficiency in podoplanin by the Wnt1 promoter and enhancer-driven Cre recombinase: Wnt1-Cre;PdpnDelta/Deltamice. In the Wnt1-Cre;PdpnDelta/Deltamice, the tooth and alveolar bone showed no morphological abnormalities and grow normally, indicating that podoplanin is not critical in the development of the tooth and bone.

Only few tissues lack lymphatic supply, such as the CNS or the inner eye. However, if the scleral border is compromised due to trauma or tumor, lymphatics are detected in the eye. Since the situation in the optic nerve (ON), part of the CNS, is not clear, the aim of this study is to screen for the presence of lymphatic markers in the healthy and lesioned ON. Brown Norway rats received an unilateral optic nerve crush (ONC) with defined force, leaving the dura intact. Lesioned ONs and unlesioned contralateral controls were analyzed 7 days (n = 5) and 14 days (n = 5) after ONC, with the following markers: PDGFRb (pericyte), Iba1 (microglia), CD68 (macrophages), RECA (endothelial cell), GFAP (astrocyte) as well as LYVE-1 and podoplanin (PDPN; lymphatic markers). Rat skin sections served as positive controls and confocal microscopy in single optical section mode was used for documentation. In healthy ONs, PDGFRb is detected in vessel-like structures, which are associated to RECA positive structures. Some of these PDGFRb+/RECA+ structures are closely associated with LYVE-1+ cells. Homogenous PDPN-immunoreactivity (IR) was detected in healthy ON without vascular appearance, showing no co-localization with LYVE-1 or PDGFRb but co-localization with GFAP. However, in rat skin controls PDPN-IR was co-localized with LYVE-1 and further with RECA in vessel-like structures. In lesioned ONs, numerous PDGFRb+ cells were detected with network-like appearance in the lesion core. The majority of these PDGFRb+ cells were not associated with RECA-IR, but were immunopositive for Iba1 and CD68. Further, single LYVE-1+ cells were detected here. These LYVE-1+ cells were Iba1-positive but PDPN-negative. PDPN-IR was also clearly absent within the lesion site, while LYVE-1+ and PDPN+ structures were both unaltered outside the lesion. In the lesioned area, PDGFRb+/Iba1+/CD68+ network-like cells without vascular association might represent a subtype of microglia/macrophages, potentially involved in repair and phagocytosis. PDPN was detected in non-lymphatic structures in the healthy ON, co-localizing with GFAP but lacking LYVE-1, therefore most likely representing astrocytes. Both, PDPN and GFAP positive structures are absent in the lesion core. At both time points investigated, no lymphatic structures can be identified in the lesioned ON. However, single markers used to identify lymphatics, detected non-lymphatic structures, highlighting the importance of using a panel of markers to properly identify lymphatic structures.

Trafficking cells frequently transmigrate through epithelial and endothelial monolayers. How monolayers cooperate with the penetrating cells to support their transit is poorly understood. We studied dendritic cell (DC) entry into lymphatic capillaries as a model system for transendothelial migration. We find that the chemokine CCL21, which is the decisive guidance cue for intravasation, mainly localizes in the trans-Golgi network and intracellular vesicles of lymphatic endothelial cells. Upon DC transmigration, these Golgi deposits disperse and CCL21 becomes extracellularly enriched at the sites of endothelial cell-cell junctions. When we reconstitute the transmigration process in vitro, we find that secretion of CCL21-positive vesicles is triggered by a DC contact-induced calcium signal, and selective calcium chelation in lymphatic endothelium attenuates transmigration. Altogether, our data demonstrate a chemokine-mediated feedback between DCs and lymphatic endothelium, which facilitates transendothelial migration.

Trans-endothelial migration (TEM) is essential for leukocyte circulation. While much is known about trans-blood endothelial migration, far less is known about trans-lymphatic endothelial migration. We established an in vitro system to evaluate lymphatic TEM for various cell types across primary mouse and human lymphatic endothelial cells (LEC), and validated the model for the murine LEC cell line SVEC4-10. T cells exhibited enhanced unidirectional migration from the basal (abluminal) to the apical (luminal) surface across LEC, whereas for blood endothelial cells (BEC) they migrated similarly in both directions. This preferential, vectorial migration was chemotactic toward many different chemoattractants and dose-dependent. Stromal protein fibers, interstitial type fluid flow, distribution of chemokines in the stromal layer, and inflammatory cytokines influenced LEC phenotype and leukocyte TEM. Activated and memory CD4 T cells, macrophages, and dendritic cell (DC) showed chemoattractantDeltadriven vectorial migration, while CD8 T cell migration across LEC was not. The system was further validated for studying cancer cell transmigration across lymphatic endothelium. This model for lymphatic TEM for various migrating and endothelial cell types possesses the capacity to be high-throughput, highly reproducible and integrate the complexities of lymphatic biology, stromal variability, chemoattractant distribution, and fluid flow.

Lymphatic vessels have been traditionally considered as passive transporters of fluid and lipids. However, it is apparent from recent literature that the function of lymphatic vessels is not only restricted to fluid balance homeostasis but also extends to regulation of immune cell trafficking, antigen presentation, tolerance, and immunity, all which may impact the progression of inflammatory responses and diseases such as cancer. The lymphatic system and the immune system are intimately connected, and there is emergent evidence for a crosstalk between T cell and lymphatic endothelial cell (LEC). This review describes how LECs in lymph nodes can affect multiple functional properties of T cells and the impact of these LEC-driven effects on adaptive immunity and, conversely, how T cells can modulate LEC growth. The significance of such crosstalk between T cells and LECs in cancer will also be discussed.

Fetal akinesia deformation sequence is a clinically and genetically heterogeneous disorder characterized by a variable combination of fetal akinesia, intrauterine growth restriction, developmental abnormalities such as cystic hygroma, hydrops fetalis, pulmonary hypoplasia, occasional arthrogryposis, and pterygia. The pathogenetic mechanisms of fetal akinesia deformation sequence include neuropathy, muscular disorders, neuromuscular junction disorders, maternal myasthenia gravis, restrictive dermopathy and others. We here report an Egyptian family presenting with recurrent lethal multiple pterygium syndrome. The diagnosis was based on antenatal sonographic demonstration of complete fetal akinesia and a large cystic hygroma with severe limb contractures evident on postmortem examination. Next generation sequencing performed on the second affected fetus identified a novel homozygous essential splice-site variant in the nebulin gene. In conclusion, our report adds further evidence for the involvement of the nebulin gene in the etiology of fetal akinesia deformation sequence/lethal multiple pterygium syndrome.

BACKGROUND: Muscle enzymes are cleared from the extracellular space by the lymphatic system, while smaller proteins enter the bloodstream directly. We investigated if manual lymphatic drainage (MLD), local cryotherapy (CRY), and rest (RST) differently affect the time course of creatine kinase (CK, 84 kDa) and heart-type fatty acid binding protein (h-FABP, 15 kDa) in the blood. DESIGN: Randomized controlled trial. METHODS: After 4x20 unilateral, eccentric accentuated knee extensions (with one-third of the maximal isometric force) 30 sports students randomly received either a 30 min MLD, CRY or they rested (RST) for the same amount of time. CK, h-FABP, neutrophil granulocytes, and the perceived muscle soreness were assessed before, immediately after, and 1 h, 4 h, and 24 h after the exercise. RESULTS: All measures increased significantly (p < 0.001) after the protocol indicating that muscle damage was induced. However, the responses did not differ between the treatments. CONCLUSIONS: Large and small damage markers were not affected differently by MLD, CRY, or RST, when applied for 30 min and no beneficial effects on inflammation or muscle soreness could be found for MLD and CRY when compared to RST. This information is particularly important for those sports physicians and conditioning specialists who use biochemical muscle damage markers to adjust the training load and volume of athletes'.

INTRODUCTION: GATA2 mutations are associated with several conditions, including Emberger syndrome which is the association of primary lymphedema with hematological anomalies and an increased risk for myelodysplasia and leukemia. OBJECTIVE: To describe a family with Emberger syndrome with incomplete penetrance. METHODS: A DNA sequencing of GATA2 gene was performed in the parents and offspring (five individuals in total). RESULTS: The family consisted of 5 individuals with a GATA2 null mutation (c.130G>T, p.Glu44*); three of them were affected (two of which were deceased) while two remained unaffected at the age of 40 and 13 years old. The three affected siblings (two boys and one girl) presented with lymphedema of the lower limbs, recurrent warts, epistaxis and recurrent infections. Two died due to hematological abnormalities (AML and pancytopenia). In contrast, the two other family members who carry the same mutation (the mother and one brother) have not presented any symptoms and their blood tests remain normal. DISCUSSION: Incomplete penetrance may indicate that GATA2 haploinsufficiency is not enough to produce the phenotype of Emberger syndrome. It could be useful to perform whole exome or genome sequencing, in cases where incomplete penetrance or high variable expressivity is described, in order to probably identify specific gene interactions that drastically modify the phenotype. In addition, skewed gene expression by an epigenetic mechanism of gene regulation should also be considered.

INTRODUCTION: Use of indocyanine green (ICG) near-infrared fluorescence as a dye to assess tissue vascularization is now well standardized. The aim of this literature review was to review and resume the most recent recommendations for ICG use in its plastic surgery applications. METHODS: A systematic literature review was performed using Medline, EMBASE, and PubMed databases to obtain the latest recommendations for ICG in plastic surgery. Inclusion criteria were all articles written in English language that evaluated pre-, intra-, or postoperative ICG applications in surgical procedures usually performed by plastic surgeons. Case reports, reviews, meta-analyses, and experimental studies on animals or cadavers were excluded after title and abstract screening. RESULTS: Of the 1389 article titles retrieved, 41 full-text articles met the inclusion criteria. ICG applications in plastic surgery were ICG lymphangiography used in sentinel lymph node mapping for breast cancer and melanoma and in microsurgery for the staging and treatment of secondary chronic lymphedema. The latest updates of ICG angiography in assessing free flaps, pedicled flaps, or large skin paddles were also retrieved. CONCLUSIONS: Large prospective studies suggest that ICG lymphography could be used as a single tracer to reliably perform sentinel lymph node biopsy. In the case of cutaneous melanoma, ICG lymphography increases node detection sensitivity and accuracy in conjunction with lymphoscintigraphy. In chronic lymphedema, it is useful for pre- and postoperative staging and intraoperative anatomical location of lymphatic pathways when lymphovenous bypass is indicated. ICG angiography is used intraoperatively to assess free flap anastomosis and design skin paddles and postoperatively to monitor buried flaps. In pedicled perforator flaps or for large skin paddles, intraoperative ICG angiography is strongly correlated with postoperative outcomes. LEVEL OF EVIDENCE: 3.

Elephantiasis is considered a cutaneous region of immune deficiency with cobblestone-like surface caused by a wart-like eruption. Verrucosis is a diffuse human papillomavirus (HPV) infection linked to immunodeficiency disorders. The objective of this study was to examine the prevalence of HPV infection in lymphedema and its pathogenic role in elephantiasis. A retrospective case-control study was performed examining lymphedematous skin and controls of peritumoral normal skin. HPV infection was evaluated at the DNA, protein, and histopathologic levels by polymerase chain reaction, immunohistochemistry, and light microscopy, respectively. Overall, 540 HPV DNAs were detected in 120 of 122 cutaneous samples (median 4 HPV DNAs per sample, range 0–9). Compared with controls, no differences existed in type or number of HPVs identified. Instead, a diverse spectrum of HPV-related histopathologies were evident, likely reflecting the multiplicity of HPV genotypes detected. Most notably, increasing histopathologic lymphedema stage significantly correlated with markers of productive HPV infection such as altered keratohyaline granules and HPV L1 capsid expression. Limitations of this study are the absence of normal skin controls not associated with neoplasia or subclinical lymphedema, and lack of assessment of HPV copy number per keratinocyte infected. In conclusion, productive HPV infection, not HPV type or numbers detected, distinguished lymphedematous skin from controls. These findings support the theory that lymphedema creates a region of depressed immunity that permits productive HPV infection, manifested clinically by diffuse papillomatosis, characteristic of elephantiasis.

OBJECTIVE: We present cytogenetic and molecular cytogenetic diagnoses of mosaic deletion of chromosome 15q11.1-q11.2 in a fetus with diffuse lymphangiomatosis. CASE REPORT: A 33-year-old woman underwent amniocentesis at 22 weeks of gestation because of fetal diffuse lymphangiomatosis involving left-side chest, abdominal cavity, thigh and vulva, and intrauterine growth restriction. Amniocentesis revealed a karyotype of 46,XX,del(15) (q11.1q11.2)[9]/46,XX[26]. The mother had a karyotype of 46,XX. The father had a karyotype of 46,XY. The parents elected to terminate the pregnancy. A 610-g female fetus was delivered at 23 weeks of gestation with large cystic lymphangioma over the left abdomen, thigh, and vulva. The umbilical cord had a karyotype of 46,XX,del(15)(q11.1q11.2)[24]/ 46,XX[16]. The placental tissue had a karyotype of 46,XX,del(15)(q11.1q11.2)[23]/ 46,XX[17]. Array comparative genomic hybridization analysis of the umbilical cord and placenta revealed a 2.42-Mb deletion of 15q11.1-q11.2 encompassing the genes of NBEAP1 and POTEB. CONCLUSION: Deletion of 15q11.1-q11.2 encompassing NBEAP1 and POTEB may be associated with diffuse lymphangiomatosis.

PURPOSE: To exploit the long 3.0T relaxation times and low flow velocity of lymphatic fluid to develop a noninvasive 3.0T lymphangiography sequence and evaluate its relevance in patients with lymphedema. MATERIALS AND METHODS: A 3.0T turbo-spin-echo (TSE) pulse train with long echo time (TEeffective = 600 msec; shot-duration = 13.2 msec) and TSE-factor (TSE-factor = 90) was developed and signal evolution simulated. The method was evaluated in healthy adults (n = 11) and patients with unilateral breast cancer treatment-related lymphedema (BCRL; n = 25), with a subgroup (n = 5) of BCRL participants scanned before and after manual lymphatic drainage (MLD) therapy. Maximal lymphatic vessel cross-sectional area, signal-to-noise-ratio (SNR), and results from a five-point categorical scoring system were recorded. Nonparametric tests were applied to evaluate study parameter differences between controls and patients, as well as between affected and contralateral sides in patients (significance criteria: two-sided P < 0.05). RESULTS: Patient volunteers demonstrated larger lymphatic cross-sectional areas in the affected (arm = 12.9 +/− 6.3 mm2 ; torso = 17.2 +/− 15.6 mm2) vs. contralateral (arm = 9.4 +/− 3.9 mm2 ; torso = 9.1 +/− 4.6 mm2) side; this difference was significant both for the arm (P = 0.014) and torso (P = 0.025). Affected (arm: P = 0.010; torso: P = 0.016) but not contralateral (arm: P = 0.42; torso: P = 0.71) vessel areas were significantly elevated compared with control values. Lymphatic cross-sectional areas reduced following MLD on the affected side (pre-MLD: arm = 8.8 +/− 1.8 mm2 ; torso = 31.4 +/− 26.0 mm2 ; post-MLD: arm = 6.6 +/− 1.8 mm2 ; torso = 23.1 +/− 24.3 mm2). This change was significant in the torso (P = 0.036). The categorical scoring was found to be less specific for detecting lateralizing disease compared to lymphatic-vessel areas. CONCLUSION: A 3.0T lymphangiography sequence is proposed, which allows for upper extremity lymph stasis to be detected in approximately 10 minutes without exogenous contrast agents. LEVEL OF EVIDENCE: 1 J. Magn. Reson. Imaging 2017.

Lymphatics play a critical role in maintaining gastrointestinal homeostasis and in the absorption of dietary lipids, yet their roles in intestinal inflammation remain elusive. Given the increasing prevalence of inflammatory bowel disease, we investigated whether lymphatic vessels contribute to, or may be causative of, disease progression. We generated a mouse model with temporal and spatial deletion of the key lymphangiogenic receptor for the adrenomedullin peptide, calcitonin receptor-like receptor (Calcrl), and found that the loss of lymphatic Calcrl was sufficient to induce intestinal lymphangiectasia, characterized by dilated lacteals and protein-losing enteropathy. Upon indomethacin challenge, Calcrlfl/fl/Prox1-CreERT2 mice demonstrated persistent inflammation and failure to recover and thrive. The epithelium and crypts of Calcrlfl/fl/Prox1-CreERT2 mice exhibited exacerbated hallmarks of disease progression, and the lacteals demonstrated an inability to absorb lipids. Furthermore, we identified Calcrl/adrenomedullin signaling as an essential upstream regulator of the Notch pathway, previously shown to be critical for intestinal lacteal maintenance and junctional integrity. In conclusion, lymphatic insufficiency and lymphangiectasia caused by loss of lymphatic Calcrl exacerbates intestinal recovery following mucosal injury and underscores the importance of lymphatic function in promoting recovery from intestinal inflammation.

OBJECTIVE: The contralateral limbs of patients with unilateral lymphedema in the lower limbs (LLs) can exhibit abnormal lymphatic circulation, even in the absence of lymphedema. This idea is based on a number of reports that have studied isolated cases using lymphoscintigraphy. It is likely that these patients previously had some form of lymphopathy, and the lymphedema arose after the action of some external factor. However, there are no studies in the literature that adequately assess the asymptomatic contralateral limbs of these patients or address the prevalence and characteristics of the abnormal lymphatic circulation in these limbs. The aim of this study was to assess the prevalence of abnormal lymphatic circulation in the asymptomatic contralateral limbs of patients with unilateral lymphedema of the LL. METHODS: Forty-three patients from the angiology and vascular surgery ward of the Hospital das Clinicas da Universidade Federal de Pernambuco with unilateral lymphedema of the LL underwent lymphoscintigraphy. All patients received a subcutaneous injection of 0.2 mL (74 MBq) of a solution of dextran 70 labeled with technetium Tc 99m in the first interdigital space of each foot. Images were obtained on two occasions: 10 minutes and 1 hour after the injection. The study design was transversal prospective. RESULTS: Among the 43 asymptomatic LLs, 30 (70%) showed abnormal lymphatic circulation. The lymphoscintigraphic abnormalities found were the following: reduced visualization of the lymphatic vessels and lymph nodes during 1 hour (83%), collateral circulation (30%), visualization of the inguinal and pelvic lymph nodes after at least 1 hour (30%), visualization of the popliteal lymph nodes (20%), dilation and lymphatic tortuosity (20%), and dermal backflow (10%). CONCLUSIONS: In this study,70% of the patients with unilateral lymphedema of the LL had some form of lymphopathy in the contralateral limb during the lymphoscintigraphic examination. These findings could favor the early treatment of these patients to prevent the disease from progressing to its most severe stage.

Introduction: Lymphoscintigraphy is an imaging technique to diagnose and characterize the severity of edema in upper and lower extremities. In lymphoscintigraphy a scoring system can increase ability of diagnostic differentiation but the use of any scoring system requires sufficient reliability. AIM: To determine inter- and intraobserver reliability of a proposed scoring system used for visual interpretation of lymphoscintigraphic imaging of lower extremities. Materials and Methods: Lymphoscintigrams in 81 persons were randomly selected from our database for retrospective evaluation. These scans were assessed according to the criteria of a scoring system by two nuclear medicine physicians at two different time-points with a three month interval. The scoring system included 8 criteria for visual interpretation of lymphoscintigraphy imaging of lower extremities. The total score was the sum of all evaluating criteria with a potential range from 0 (normal lymphatic drainage) to 58 (severe lymphatic impairment). It was used the Wilcoxon signed-rank test, percentage of agreement, weighted kappa and Intraclass Correlation Coefficient (ICC) with 95% confidence intervals for investigation of the intra- and interobserver reliabilities of the scoring system. It was also categorized the differences of the total scores in 7 different categories for graphic comparison between/within the raters. Results: It was found some differences of the ratings between the raters, which were not statistically substantial. There were high or very high percentages of agreement between the raters from 82.7% to 99.4% and within the raters from 84.6% to 99.4%. It was found moderate to very good kappa correlations of inter- or intraobserver reliability of each sign of the scoring system. The total scores obtained from all signs had good inter- and intraobserver reliability. Regarding the comparison between the raters 66% and 64% of differences of the total scores are within plus/minus one scale point[ −1, +1], and regarding the comparison within the rate 68% and 72% of the total score differences are within plus/minus one scale point[ −1, +1]. Conclusion: The scoring system used for visual qualitative evaluation of lymphoscintigraphy of lower extremities is a reliable tool for evaluating lymph transport problem in patients with lymphedema in lower extremity.

Gorham-Stout disease (GSD) is a rare condition of osteolysis with excessive lymphangiogenesis within bone tissue. The etiology of this condition remains unknown but seems to affect mainly children and young adults of both genders all over the world. Unfortunately, there is no standardized method for diagnosis; however, histopathology remains as the gold standard. This condition is often misdiagnosed due to its varying clinical presentations from case-to-case. Here, we report the case of an 8-year-old girl who presented with chronic mandibular pain during mastication and received multiple antibiotic treatment due to infectious origin suspicion. After integrating information from clinical manifestations, radiographic, laboratory, and histopathology information, she was diagnosed with GSD. Additionally, due to the lack of literature with respect to insights into biological mechanisms and standardized treatment for this condition, we underwent a literature revision to provide information related to activation of cells from the immune system, such as macrophages, T-cells, and dendritic cells, and their contribution to the lymphangiogenesis, angiogenesis, and osteoclastogenic process in GSD. It is important to consider these mechanisms in patients with GSD, especially since new studies performed in earlier stages are required to confirm their use as novel diagnostic tools and find new possibilities for treatment.

Secondary lymphedema, a life-long complication of cancer treatment, currently has no cure. Lymphedema patients have decreased quality of life and recurrent infections with treatments limited to palliative measures. Accumulating evidence indicates that T cells play a key role in the pathology of lymphedema by promoting tissue fibrosis and inhibiting lymphangiogenesis. Here using mouse models, we show that topical therapy with tacrolimus, an anti-T-cell immunosuppressive drug, is highly effective in preventing lymphedema development and treating established lymphedema. This intervention markedly decreases swelling, T-cell infiltration and tissue fibrosis while significantly increasing formation of lymphatic collaterals with minimal systemic absorption. Animals treated with tacrolimus have markedly improved lymphatic function with increased collecting vessel contraction frequency and decreased dermal backflow. These results have profound implications for lymphedema treatment as topical tacrolimus is FDA-approved for other chronic skin conditions and has an established record of safety and tolerability.

OBJECTIVE: Aim of this study is to evaluate the possibility of limb magnetic resonance lymphography (MRL) to differentiate lymphatic vessels from pathological veins, collect a specimen of the identified lymphatic vessel during operations of super microsurgical lymphatic-venular anastomosis (s-LVA) and perform immunohistochemical stainings to confirm the nature of the collected vessels. PATIENTS AND METHODS: Twenty patients presenting lymphedema were enrolled in this study. Five patients reported lower limb lymphedema and 15 patients reported upper limb lymphedema. All patients had the indication for s-LVA and underwent preoperative MRL imaging of the affected limb. A total of 57 lymphatic vessels were identified by MRL and used to guide s-LVA: all these vessels have also been used to perform an intraoperative biopsy for immunohistochemical evaluation. RESULTS: A total of 53/57 vascular structures resulted compatible with lymphatic vessels at the immunohistochemical study performed with D2-40 antibody; 3/57 specimen showed the absence of the D2-40 antibody. A significant association was found between preoperative MRL and immunohistochemical marker D2-40 on collected specimen. CONCLUSIONS: Most of the articles in the international literature report the concomitant presence of both lymphatic and venous vessels at MRL. However, no one in literature describes the possibility to differentiate venous vessels from lymphatic vessels, and this is a crucial issue for the correct evaluation of the lymphatic system in patients with limb lymphedema undergoing a future surgical correction. In the present study, MRL allowed to identify active lymphatic vessels. MRL was predictive to determine preoperatory lymphatic vessels and to perform successful s-LVA in lymphedema patients. This is the first study to prove the nature of the vessels identified at the preoperative MRL with immunohistochemical stainings.

OBJECTIVE: Aim of this paper is to present our reduction of the frequency of cellulitis before and after supramicrosurgical lymphaticovenular anastomosis (s-LVA) in lymphoedema patients, and discuss the possibility to perform this technique outside Japan. PATIENTS AND METHODS: 37 patients affected by lymphoedema were enrolled. All patients received preoperative indocyanine green lymphography. Under local anaesthesia s-LVA was performed on all patients. All patients were followed for 1 year. Lymphoedema was staged using the lymphoedema staging classification recommended by the International Society of Lymphology. Cellulitis rate was recorded for all patients the year before and after the s-LVA. A t-test was used to evaluate differences in the frequency of cellulitis the year before surgery and the year following surgery. RESULTS: Cellulitis incidence decreased in all patients, with a mean 1.7 cases the year before s-LVA and 0.1 the year after s-LVA. A significant difference between preoperative and postoperative cellulitis rate was found (p = 0.0012). CONCLUSIONS: This study reports our s-LVA case series of lymphoedema patients. With the proper learning curve, s-LVA may be reproduced and lymphoedema patients may gain a better quality of life and a reduced cellulitis rate.

Primary lymphedema in the pediatric population remains poorly diagnosed and misunderstood due to a lack of information on the causation and underlying anatomy of the lymphatic system. Consequently, therapeutic protocols for pediatric patients remain sparse and with little evidence to support them. In an effort to better understand the causation of primary pediatric lymphedema and to better inform clinical care, we report the use of near-infrared fluorescence lymphatic imaging on the extremities of an alert, 21-month-old boy who presented with unilateral right arm and hand lymphedema at birth. The imaging results indicated an intact, apparently normal lymphatic anatomy with no obvious malformation, but with decreased lymphatic contractile function of the affected upper extremity relative to the contralateral and lower extremities. We hypothesized that the lack of contraction of the lymphatic vessels rather than an anatomic malformation was the source of the unilateral extremity swelling, and that compression and manual lymphatic drainage could be effective treatments.

OBJECTIVES: Pulmonary lymphangiectasia associated with hypoplastic left heart syndrome with an intact or restrictive atrial septum may result from increased left atrial pressure, and is associated with worse outcomes following staged reconstruction due to lung dysfunction and significant hypoxaemia. Our objective was to characterise the incidence of pulmonary lymphangiectasia in cases of early mortality following stage 1 reconstructions. METHODS: An institutional cardiac surgical database was retrospectively searched for patients who died within 30 days following a stage 1 reconstruction between 1 January, 1984 and 31 December, 2013. During that period, 1669 stage 1 procedures were performed. Autopsy lung specimens were reviewed by a paediatric pathologist. Patients who died of suspected technical issues were excluded. RESULTS: A total of 54 patients were included, and of these seven cases (8.5%) of pulmonary lymphangiectasia were identified. The mean estimated gestational age was 38.2+/−2.4 weeks, and the mean birth weight was 3.0+/−0.6 kg. The median interval between surgery and death was 1 day (with a range from 0 to 18 days). The atrial septum was intact in one patient (14.3%), restrictive in three patients (42.9%), and unrestrictive in three patients (42.9%). CONCLUSIONS: Pulmonary lymphangiectasia may develop in hypoplastic left heart syndrome with or without a restrictive atrial septum. As standard prenatal diagnostic evaluations and treatment methods for pulmonary lymphangiectasia are limited, this may be an important contributor to early and late mortality following stage 1 reconstruction for hypoplastic left heart syndrome.

The thoracic lymphatic disorders are a heterogeneous group of uncommon conditions that are associated with thoracic masses, interstitial pulmonary infiltrates, and chylous complications. Accurate diagnosis of the thoracic lymphatic disorders has important implications for the newest approaches to management, including embolization and treatment with antilymphangiogenic drugs. New imaging techniques to characterize lymphatic flow, such as dynamic contrast-enhanced magnetic resonance lymphangiogram, are redefining approaches to disease classification and therapy.

The lymphatic vasculature has been regarded as a passive conduit for interstitial fluid and responsible for the absorption of macromolecules such as proteins or lipids and transport of nutrients from food. However, emerging data show that the lymphatic vasculature system plays an important role in immune modulation. One of its major roles is to coordinate antigen transport and immune-cell trafficking from peripheral tissues to secondary lymphoid organs, lymph nodes. This perspective was recently updated with the notion that the interaction between lymphatic endothelial cells and leukocytes controls the immune-cell migration and immune responses by regulating lymphatic flow and various secreted molecules such as chemokines and cytokines. In this review, we introduce the lymphatic vasculature networks and genetic transgenic models for research on the lymphatic vasculature system. Next, we discuss the contribution of lymphatic endothelial cells to the control of immune-cell trafficking and to maintenance of peripheral tolerance. Finally, the physiological roles and features of the lymphatic vasculature system are further discussed regarding inflammation-induced lymphangiogenesis in a pathological condition, especially in mucosal tissues such as the gastrointestinal tract and respiratory tract.

Lymphatic vessels are vital for the trafficking of immune cells from the interstitium to draining lymph nodes during inflammation. Hypertension is associated with renal infiltration of activated immune cells and inflammation; however, it is unknown how renal lymphatic vessels change in hypertension. We hypothesized that renal macrophage infiltration and inflammation would cause increased lymphatic vessel density in hypertensive rats. Spontaneously hypertensive rats (SHR) that exhibit hypertension and renal injury (SHR-A3 strain) had significantly increased renal lymphatic vessel density and macrophages at 40 wk of age compared with Wistar-Kyoto (WKY) controls. SHR rats that exhibit hypertension but minimal renal injury (SHR-B2 strain) had significantly less renal lymphatic vessel density compared with WKY rats. The signals for lymphangiogenesis, VEGF-C and its receptor VEGF-R3, and proinflammatory cytokine genes increased significantly in the kidneys of SHR-A3 rats but not in SHR-B2 rats. Fischer 344 rats exhibit normal blood pressure but develop renal injury as they age. Kidneys from 24-mo- and/or 20-mo-old Fischer rats had significantly increased lymphatic vessel density, macrophage infiltration, VEGF-C and VEGF-R3 expression, and proinflammatory cytokine gene expression compared with 4-mo-old controls. These data together demonstrate that renal immune cell infiltration and inflammation cause lymphangiogenesis in hypertension- and aging-associated renal injury.

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Discuss the key points in diagnosing lymphedema. 2. Understand the imaging modalities that facilitate diagnosis and surgical planning. 3. Appreciate the indications for both physiologic and ablative procedures. 4. Recognize the potential role of lymphaticovenular anastomosis and vascularized lymph node transfer in the treatment of patients with lymphedema. SUMMARY: Lymphedema is an incurable disease caused by insufficient lymphatic drainage leading to abnormal accumulation of interstitial fluid within the soft tissues. Although this condition may result from a primary structural defect of the lymphatic system, most cases in developed countries are secondary to iatrogenic causes. The diagnosis of lymphedema can be made readily by performing a clinical history and physical examination and may be confirmed by imaging studies such as lymphoscintigraphy, magnetic resonance lymphangiography, or indocyanine green lymphangiography. Nonsurgical treatment continues to be the mainstay of lymphedema management. However, advances in microsurgical techniques have revolutionized surgical options for treating lymphedema, and emerging evidence suggests that reconstructive methods may be performed to restore lymphatic flow. Procedures such as lymphaticovenular anastomosis and vascularized lymph node transfer can potentially offer a more permanent solution to chronic lymphedema, and initial studies have demonstrated promising results.

Multifocal lymphangioendotheliomatosis with thrombocytopenia (MLT) is a rare disease characterized by congenital and progressive vascular lesions of the skin and gastrointestinal tract that may be associated with thrombocytopenia and possibly life-threatening gastrointestinal bleeding. Reports published on the disease and treatment strategies are scarce. We present two cases of MLT treated with sirolimus.

Swelling is the most common symptom of extremities lymphedema. Clinical evaluation and laboratory analysis were conducted after far infrared radiation (FIR) treatment on the main four components of lymphedema: fluid, fat, protein, and hyaluronan. Far infrared radiation is a kind of hyperthermia therapy with several and additional benefits as well as promoting microcirculation flow and improving collateral lymph circumfluence. Although FIR therapy has been applied for several years on thousands of lymphedema patients, there are still few studies that have reported the biological effects of FIR on lymphatic tissue. In this research, we investigate the effects of far infrared rays on the major components of lymphatic tissue. Then, we explore the effectiveness and safety of FIR as a promising treatment modality of lymphedema. A total of 32 patients affected by lymphedema in stage II and III were treated between January 2015 and January 2016 at our department. After therapy, a significant decrease of limb circumference measurements was noted and improving of quality of life was registered. Laboratory examination showed the treatment can also decrease the deposition of fluid, fat, hyaluronan, and protein, improving the swelling condition. We believe FIR treatment could be considered as both an alternative monotherapy and a useful adjunctive to the conservative or surgical lymphedema procedures. Furthermore, the real and significant biological effects of FIR represent possible future applications in wide range of the medical field.

OBJECTIVE: The popularity of contemporary microsurgical techniques in treatment of lower-limb lymphedema calls for better visualization of the lymphatic system, both preoperatively and intra-operatively. The aim of this prospective study was to investigate the feasibility of a novel combination of 68Ga-NEB positron emission tomography (PET) with magnetic resonance lymphography (MRL) in evaluating lymphedema and guiding surgical intervention. METHODS: A total of 11 patients (F 9, M 2, age range 29–69 y) with lower-limb lymphedema classified into stage I to III were recruited. PET acquisition was performed at 30, 60 and 90 min after subcutaneous injection of the albumin-binding radiotracer 68Ga-NEB into the bilateral first web spaces of the feet. All the patients were also subjected to 99mTc-sulfur colloid (SC) lymphoscintigraphy for comparison. Gd-DTPA-enhanced magnetic resonance imaging (MRI) was performed using sequences specialized for lymphatic vessel scans. All the patients underwent surgical interventions within a week. The surgical approach includes the use of a linear marker for edema localization and indocyanine green (ICG) lymphography with a near-infrared surgical navigation system intra-operatively. RESULTS: Lymph transport in lymphatic channels was clearly observed by visualization of 68Ga-NEB activity in the lymphatic vessels and within lymph nodes for all 11 patients as well as the visualization of the edema section plane with dermal backflow (DB), abnormally increased and disconnected uptake along the lymphatic channels. Preoperative 68Ga-NEB PET combined with MRL provides advantageous three-dimensional images, higher temporal resolution, significantly shorter time lapse before image acquisition after tracer injection and more accurate pathological lymphatic vessel distribution than 99mTc-SC lymphoscintigraphy combined with MRI. CONCLUSION: This study documented an effective imaging pattern to combine 68Ga-NEB PET and MRL in patients with lower-limb lymphedema. This strategy demonstrated significant advantage over 99mTc-SC lymphoscintigraphy/MRL in the evaluation of lymphedema severity, staging and pathological location of lymph vessels to make an individualized treatment plan. Dual 68Ga-NEB PET/MRL is thus recommended before the operation for staging and therapy planning.

We propose a practical approach for performing high-resolution MR lymphangiography (MRL). We shall discuss and illustrate the technical approach for the visualization of lymphatic vessels in patients suffering from lymphedema, how to distinguish lymphatic vessels from veins, and MRL role in supermicrosurgery treatment planning. A brief review of literature, from a technical point of view, is also reported.

Bilateral lower extremity inflammatory lymphedema (BLEIL) is a recently described condition that presents with exquisite tenderness, erythema and edema of the lower leg, ankle and dorsal foot resembling an acute cellulitis. It was first reported in healthy, young adult military basic trainees with a normal body mass index during the first 72 hours of arrival to basic training. It occurs while standing at attention for many hours, and shows rapid resolution with elevation and rest. We report an additional case of BLEIL and describe the histopathology of this case and 2 of the previously reported cases. All 3 biopsies showed a deep perivascular infiltrate of neutrophils with karyorrhectic debris and prominent red blood cell extravasation. One of the 3 cases was positive for complement by direct immunofluorescence. We postulate this condition represents a deep leukocytoclastic vascultis with secondary reactive lymphedematous changes.

BACKGROUND: We investigate the effectiveness of lymphaticovenous anastomosis (LVA) in releasing lymphedema-associated pain. METHODS: We performed a retrospective analysis. Subjects of this study included lower extremity lymphedema patients who presented persistent and constant degrees of pain in their lower limbs. LVA was performed under local anesthesia. The preoperative lower extremity pain and postoperative lower extremity pain were surveyed using the visual analog scale on a score from 0 to 10. The circumferences of the limbs were also recorded. RESULTS: A total of 8 patients (16 lower limbs) were included. The subjects included 1 man and 7 women, and their average age was 72 years. The average follow-up period was 17 months. The average preoperative and postoperative visual analog scale scores were 5.3 and 1.8, respectively. Moreover, 7 patients who had records of their lower extremity circumference observed an average changing rate of −4.7% in lower extremity lymphedema index after the surgery. CONCLUSION: LVA can release the pain in the affected limbs of lymphedema.

Morbihan disease (MD) is rosacea-like disease characterized by persistent lymphedema on the upper half of the face. Currently, there is no established standard treatment for MD. Recently, MD has been reported to be associated with the infiltration of mast cells. The aim of this study was to investigate the association of treatment response and mast cell infiltration in MD. We report four cases of MD that were successfully treated with long-term oral doxycycline therapy.

PURPOSE: To evaluate the efficacy of intralesional bleomycin injection in the management of lymphangiomas of the orbit. METHODS: This prospective noncomparative interventional case study included 13 patients with orbital lymphangiomas. Reconstituted bleomycin 1–5 ml (0.5 IU/kg body weight; maximum, 15 IU/ml) was injected with 2% lignocaine in the lesion as seen on imaging or, in deeper lesions, under ultrasound guidance. Repeat injections were administered when required after every 4 weeks. The decision to retreat was based on clinical and radiological evidence of response. RESULTS: Patients were treated with 1–6 injections of bleomycin 0.5 IU/kg body weight. Dramatic response was achieved in all cases. During the mean follow-up period of 19.69 months (range, 7–26 months) none of the patients experienced recurrence or significant complication. CONCLUSIONS: In this patient cohort lymphangiomas of the orbit showed favorable and promising results with intralesional injections of bleomycin. This treatment should be considered as a first-line therapy for lymphangiomas of the orbit.

BACKGROUND: The lymphatic vasculature provides a route for cancer metastases, and its dysfunction after cancer treatment can result in lymphedema. However, changes in the lymphatics before, during, and after surgery and radiation remain unclear. METHODS: Near-infrared fluorescence lymphatic imaging was performed before and after lymph node dissection and fractionated radiotherapy to assess changes in external lymphatic function. RESULTS: Patients who underwent both lymph node dissection and radiotherapy developed lymphatic dermal backflow on treated sides ranging from days after the start of radiotherapy to weeks after its completion, whereas contralateral regions that were not associated with lymph node dissection but also treated with radiotherapy experienced no such changes in external lymphatic anatomies. CONCLUSION: The external lymphatics undergo transient changes during and weeks after lymph node dissection and radiotherapy. (c) 2017 Wiley Periodicals, Inc. Head Neck 39: 1177–1188, 2017.

BACKGROUND: Fabry disease (FD) is a treatable multisystem disease caused by a defect in the alpha-galactosidase gene. Ocular signs of FD, including corneal verticillata, are among the earliest diagnostic findings. Conjunctival lymphangiectasia (CL) has not previously been associated with FD. METHODS: We examined the eyes of a cohort of 13 adult patients, eight men and five women, with documented classic FD, all treated with enzyme replacement therapy (ERT) at the University of Alabama at Birmingham between February 2014 and April 2015. The average age was 48 years with a range of 35–55 years for men and 21–71 years for women. The mean duration of ERT was 8.4 years (men 8.9 years, women 7.6 years) with a range of 4–14 years. Classical Fabry mutations included Q283X, R227X, W236X and W277X. A high resolution Haag-Streit BQ-900 slit lamp with EyeCap imaging system was used to record conjunctival images. RESULTS: CL was observed in 11 of the 13 patients (85%) despite long-term ERT. Clinical presentations included single cysts, beaded dilatations and areas of conjunctival oedema. Lesions were located within 6 mm of the corneal limbus. Ten of the 13 subjects (77%) had Fabry-related cataracts and all 13 demonstrated bilateral corneal verticillata. Twelve of the 13 patients had evidence of dry eye, 9 of whom were symptomatic, and 10 had peripheral lymphoedema. CONCLUSION: CL represents a common but under-recognised ocular manifestation of FD, which persists despite ERT, and is often accompanied by peripheral lymphoedema and dry eye syndrome.

OBJECTIVES: To evaluate radiographic characteristics and to identify locations of cervicofacial lymphatic malformations in children based on known lymph node groupings. METHODS: Retrospective chart review of pediatric patients with cervicofacial lymphatic malformations who underwent imaging with magnetic resonance imaging (MRI), computed tomography (CT) or ultrasonography (US). Ninety charts were reviewed from November 2005 to June 2015. Demographic information and imaging characteristics were evaluated. RESULTS: Ninety children were included. The average age at presentation was 52 months (range, 1 day to 170 months). Imaging modalities were MRI in 73 (81%), CT in 7 (8%), US in 6 (7%), and multimodality imaging in 4 (4%) cases. Nearly half (49%) of lesions were found in the parotid and submandibular nodal group, 32% in the cervical group, and 19% in the midline face and oral cavity group. The lymphatic malformations were found on the left in 39 (43%) of cases, on the right in 30 (33%) of cases, and were bilateral in 21 (23%) cases. Nineteen (21%) lesions were macrocystic, twenty-two (24%) were microcystic, and forty-nine (49%) had mixed features. Mixed lesions were more likely to be extensive and involve multiple lymph node groups (P = 0.0005). Adjacent lymphadenopathy was present in 20 (22%) among all subjects, with an average size of 1.22 (+/− 1.92) cm in the short-axis. CONCLUSION: The results of this study demonstrate three lymph node groupings in which LM are commonly identified. The midline face and oral cavity lesions are predominantly microcystic, the parotid and submandibular lesions are predominately of mixed morphology, and the cervical lesions are predominately macrocystic and mixed. Further studies are needed to determine if such a classification system demonstrates clinically significant difference in disease progression and response to therapy.

The Lymphatic Microsurgical Preventing Healing Approach (LYMPHA) procedure entails performing a lymphovenous bypass (LVB) at the time of axillary lymph node dissection to reduce lymphedema risk. The two most common fluorophores utilized in LVB are blue dye and indocyanine green. We developed a novel application of fluorescein isothiocyanate for intraoperative lymphatic mapping. Our goal is to demonstrate the safety and efficacy of fluorescein isothiocyanate for this application. We reviewed a prospectively collected database on breast cancer patients who underwent LYMPHA from March to September 2015. Fluorescein isothiocyanate was used to identify arm lymphatic channels after axillary lymph node dissection to perform an LVB between disrupted lymphatics and axillary vein tributaries. Data on preoperative and intraoperative variables were analyzed. Thirteen patients underwent LYMPHA with intraoperative fluorescein isothiocyanate lymphatic mapping from March to September 2015. Average patient age was 50 years with a mean body mass index of 28. On average, 3.4 lacerated lymphatic channels were identified at an average distance of 2.72 cm (range, 0.25–5 cm) caudal to the axillary vein. On average, 1.7 channels were bypassed per patient. Eleven anastomoses were performed to the accessory branch of the axillary vein and 1 to a lateral branch. In 1 patient, a bypass was not performed due to poor lymphatic caliber and inadequate length of the harvested vein tributary. No intraoperative adverse events were noted. Fluorescein isothiocyanate is a safe and effective method for intra-operative lymphatic mapping. Fluorescein isothiocyanate imaging allows for simultaneous dissection and lymphatic visualization, making it an ideal agent for lymphatic mapping and dissection in open surgical fields, such as in the LYMPHA procedure.

Advances in our ability to identify lymphatic endothelial cells and differentiate them from blood endothelial cells have led to important progress in the study of lymphatic biology. Over the past decade, pre-clinical and clinical studies have shown that there are changes to the lymphatic vasculature in nearly all lung diseases. Efforts to understand the contribution of lymphatics and their growth factors to disease initiation, progression and resolution have led to seminal findings establishing critical roles for lymphatics in lung biology spanning from the first breath after birth to asthma, tuberculosis, and lung transplantation. However, in other diseases, it remains unclear if lymphatics are part of the overall lung remodeling process or real contributors to disease pathogenesis. The goal of this translational review is to highlight some of the advances in our understanding of the role(s) of lymphatics in lung disease and shed light on the critical needs and unanswered questions that might lead to novel translational applications.

OBJECTIVE: The aim of this study was to analyze the findings of MDCT performed after direct lymphangiography in patients with diffuse pulmonary lymphangiomatosis. MATERIALS AND METHODS: Twenty-three patients (13 male and 10 female patients) diagnosed with diffuse pulmonary lymphangiomatosis on the basis of clinical features and findings from imaging, bronchoscopy, and pathologic analysis were retrospectively evaluated. All patients underwent pulmonary MDCT after direct lymphangiography, surgical operation or open lung biopsy, and histopathologic examination. MDCT images were analyzed by two experienced radiologists independently. RESULTS: MDCT after direct lymphangiography revealed numerous intrathoracic abnormalities, including abnormal distribution of contrast medium, dilatation of lymphatic channels, mediastinal soft-tissue infiltration, and peribronchovascular thickening. Nineteen patients had interlobular septal thickening, 18 had diffuse ground-glass opacities, 22 had pleural effusion, 14 had extrapleural soft-tissue thickening, 20 had pericardial effusion and thickened pericardium, 10 had multiple lymphadenopathy in mediastinum, and five had mediastinal, pericardial, and thoracic aeroceles. CONCLUSION: MDCT performed after direct lymphangiography is well suited to clarify the characteristics of intrathoracic disorders and is an excellent tool in the diagnosis of diffuse pulmonary lymphangiomatosis.

As a new trial, we used interstitial computed tomography-lymphography (CT-LG) in 10 patients with lower extremity lymphedema (n = 20 limbs) at stage 0, 1, 2, or 3 under the International Society of Lymphology (ISL) classification. In all cases, CT-LG, lymphoscintigraphy, and indocyanine green fluorescence-lymphography (ICG-LG) were performed. In the examination of the ascending level of depicted lymphatic vessels, we measured the diameters of lymphatic vessels detected with CT-LG and conducted an image analysis of dermal backflow of lymph (DB). CT-LG had better resolution than lymphoscintigraphy and enabled the clear visualization of lymphatic vessels with a minimum lumen size of 0.7 mm. CT-LG also showed the three-dimensional architecture of the DB, which originated from deep lymphatic collectors via branched small lymphatic vessels. Our findings are quite valuable not only for detailed examinations of lymphedematous sites and for the lymphedema surgery, but also for investigations of the pathogenesis of lymphedema which has not yet been established. We observed that lymphoscintigraphy could show the lymphatic vessels up to the thigh level in all cases, whereas CT-LG enabled the vessels' visualization up to the leg level at maximum. In conclusion, CT-LG provided adequate and detailed three-dimensional imaging of the lymphatic system in lymphedema patients.

An eight-yr-old female with a history of multifocal lymphangioendotheliomatosis and thrombocytopenia presented for MVT. The patient had multiple vascular lesions in the skin and stomach in infancy. Although her cutaneous lesions resolved with vincristine and methylprednisolone, her gastric lesions persisted. Eight yr later, she was diagnosed with portal hypertension and decompensating liver function despite therapy with bevacizumab, propranolol, furosemide, and spironolactone. Upon presentation, she was found to have a Kasabach-Merritt-like coagulopathy in association with multiple lesions in her GI tract and persistent gastric lesions. Although treatment with methylprednisolone and sirolimus normalized her coagulation factors and d-dimer levels, she never developed sustained improvement in her thrombocytopenia. Her liver function continued to deteriorate and she developed hepatorenal syndrome. Given better outcomes after OLT in comparison with MVT, she underwent OLT, with the plan to manage her GI lesions with APC post-transplant. Post-transplant, her liver function and coagulopathy normalized, and GI tract lesions disappeared upon screening with capsule endoscopy. The patient is doing well, without recurrence of either GI lesions or thrombocytopenia, at 18 months after transplantation.

Somatic mutations in PIK3CA cause many overgrowth syndromes that have been recently coined the “PIK3CA-Related Overgrowth Spectrum.” Here, we present seven molecularly confirmed patients with PIK3CA-Related Overgrowth Spectrum, including patients with Congenital Lipomatous Overgrowth, Vascular Malformations, Epidermal Nevi, Scoliosis/Skeletal and Spinal syndrome, Klippel-Trenaunay syndrome, lymphatic malformation and two with atypical phenotypes that cannot be classified into existing disease categories. The literature on PIK3CA-Related Overgrowth Spectrum, suggests that PIK3CA c.1258T>C; p.(Cys420Arg), c.1624G>A; p.(Glu542Lys), c.1633G>A; p.(Glu545Lys), c.3140A>G; p.(His1047Arg), and c.3140A>T; p.(His1047Leu) can be identified in approximately 90% of patients without brain overgrowth. Therefore, droplet digital polymerase chain reaction targeting these mutation hotspots could be used as the first-tier genetic test on patients with PIK3CA-Related Overgrowth Spectrum who do not have signs of overgrowth in their central nervous system. (c) 2017 Wiley Periodicals, Inc.

PURPOSE: Lymphedema is a chronic and disabling sequel of breast cancer treatment that can be treated by lymphatico-venous anastomosis (LVA). Artificial connections between the venous and lymphatic system are performed supermicrosurgically. This prospective study analyses the effect of LVA on quality of life. METHODS: A prospective study was performed between November 2015 and July 2016 on consecutive patients in the Maastricht University Medical Centre. Quality of life was considered as the primary outcome, and the Lymphedema International Classification of Functioning (Lymph-ICF) questionnaire was used. Discontinuation of compressive stockings and arm volume, using the Upper Extremity Lymphedema index (UEL-index), were the secondary outcomes. RESULTS: Twenty women with early-stage breast cancer-related lymphedema (BCRL) were included. The mean age was 55.9 +/− 4 years and the median BMI was 25.1 [21–30] kg/m2. The mean follow-up was 7.8 +/− 1.5 months. Statistically significant improvement in quality of life was achieved in the total score and for all the quality of life domains after one year of follow-up (p < 0.05). The discontinuation rate in compressive stockings use was 85%. The difference in mean relative volume did not show a statistically significant decrease. CONCLUSIONS: LVA for early-stage BCRL resulted in a significant improvement in quality of life and a high rate in stocking discontinuation.

BACKGROUND: Lymphedema is one of the most dreaded side effects to any cancer treatment involving lymphadenectomy. Progressed lymphedema is adversely complex and currently there is no widely acknowledged curative treatment. Therefore recent focus has shifted to risk reduction and prevention. It has been hypothesized that bypassing lymphatic vessels to veins prophylactically, could minimize the lymphatic dysfunction seen following lymphadenectomy. METHODS: To investigate this possible future treatment modality, we performed a systematic meta-analysis of studies treating patients with prophylactic lymphovenous analysisstomosis (LVA) for the prevention of secondary lymphedema following lymphadenectomy. A systematic search yielded 12 articles included in the qualitative analysis and four of these were further eligible to be included in the quantitative analysis. RESULTS: We found that patients treated with prophylactic LVA had a significant reduction in lymphedema incidence (Relative risk: 0.33, 95%CI: 0.19 to 0.56) when compared to patients receiving no prophylactic treatment (P < 0.0001). CONCLUSION: Prophylactic LVA in relation to lymphadenectomy shows promising results, however because of the low number of eligible studies and method heterogeneity between studies, there is an urgent need for uniformly high quality studies, before the treatment can be concluded effective.

Several lymphangiogenic factors, such as vascular endothelial growth factors (VEGFs), have been found to drive the development of lymphatic metastasis in bladder cancer (BCa).Here, we have analyzed the gene expression of lymphangiogenic factors in tissue specimens from 12 non-muscle invasive bladder cancers (NMIBC) and 11 muscle invasive bladder cancers (MIBC), considering tumor and tumor-adjacent normal bladder areas obtained from the same organs. We then compared the results observed in patients with those obtained after treating human primary bladder microvascular endothelial cells (MEC) with either direct stimulation with VEGF-A or VEGF-C or by co-culturing (trans-well assay) MEC with bladder cancer cell lines varying in VEGF-A and VEGF-C production based on tumor grade.The genes of three markers of lymphatic endothelial commitment and development (PDPN, LYVE-1 and SLP-76) were significantly overexpressed in tissues of MIBC patients showing positive lymphovascular invasion (LVI+), lymph node metastasis (Ln+) and tumor progression. Their expression was also significantly enhanced either after direct stimulation of MEC by VEGF-A and VEGF-C or in the trans-well assay with each bladder cancer cell line.SLP-76 showed the highest gene expression. Both VEGF-A and VEGF-C also enhanced the expression of SLP-76 protein in MEC. However, a correlation between increase of SLP-76 gene expression and the ability of MEC to migrate could only be seen after induction by VEGF-C.The significant expression of SLP-76 in LVI+/Ln+ progressive MIBC and its overexpression in MEC after VEGF-A and VEGF-C stimulation suggest the need to develop this regulator of developmental lymphangiogenesis as a diagnostic tool in BCa.

BACKGROUND: Potassium (K) channels play an important role in lymph pump activity, lymph formation, lymph transport, and the functions of lymph nodes. No studies have examined the relationship between K channel candidate genes and the development of secondary lymphedema (LE). OBJECTIVE: The study purpose was to evaluate for differences in genotypic characteristics in women who did (n = 155) or did not (n = 387) develop upper extremity LE following breast cancer treatment based on an analysis of single-nucleotide polymorphisms (SNPs) and haplotypes in 10 K channel genes. METHODS: Upper extremity LE was diagnosed using bioimpedance resistance ratios. Logistic regression analyses were used to identify those SNPs and haplotypes that were associated with LE while controlling for relevant demographic, clinical, and genomic characteristics. RESULTS: Patients with LE had a higher body mass index, had a higher number of lymph nodes removed, had more advanced disease, received adjuvant chemotherapy, received radiation therapy, and were less likely to have undergone a sentinel lymph node biopsy. One SNP in a voltage-gated K channel gene (KCNA1 rs4766311), four in two inward-rectifying K channel genes (KCNJ3 rs1037091 and KCNJ6 rs2211845, rs991985, rs2836019), and one in a two-pore K channel gene (KCNK3 rs1662988) were associated with LE. DISCUSSION: These preliminary findings suggest that K channel genes play a role in the development of secondary LE.

BACKGROUND: Overexpression of Vav3, a gene involved in signal transduction, promotes invasion and inhibits apoptosis in several cancers. The clinical value of the protein product of this gene, Vav3, in the peripheral blood of gastric cancer patients is unknown. We hypothesised increased serum Vav3 that related to tissue levels and lymph node metastases. In addition, we further explored its clinical value in respect of linked molecules Rac-1, MMP-7 and ICAM-1 Methods: 120 gastric cancer patients who had radical surgery were enrolled. Immunohistochemistry was used to determine the expressions of Vav3, Rac-1, MMP-7 and ICAM-1 in gastric cancer mucosa and normal mucosa. ELISA was used to detect these proteins in peripheral blood of gastric cancer patients and 100 age- and sex-matched healthy controls. RESULTS: Vav3, Rac-1 and MMP-7 (P < 0.001), but not ICAM-1 (P = 0.303) were more highly expressed by cancer tissues than normal gastric mucosa. Serum levels of all molecules were higher than those in healthy subjects (P < 0.001). Levels of Vav3, Rac-1 and MMP-7 decreased 2 weeks postoperatively (all P < 0.001) but there was no change in ICAM-1 (P = 0.192). Similarly, increased levels of Vav3, Rac-1 and MMP-7 were present in patients with lymphatic metastasis than those without (all P < 0.001) but there was no difference in ICAM-1 levels (P = 0.378). There were positive correlations between Vav3 with Rac-1 and MMP-7 in cancer tissues (P < 0.001), and also between Vav3 and Rac-1 in pre-surgery blood (P = 0.003). CONCLUSIONS: Vav3 in peripheral blood may serve as a biomarker for gastric cancer, and to predict the lymphatic metastasis in gastric cancer.

INTRODUCTION: Lymphedema is one of the most serious complications following breast cancer treatment. While many risk factors are well described the role of seroma formation has recently produced mixed results. Therefore, we aimed to evaluate if seroma is a risk factor for development of lymphedema in one of the largest retrospective cohort studies. MATERIAL AND METHODS: We included all patients with unilateral breast cancer treated in the period of 2008–2014. Data regarding treatment and breast cancer characteristics were retrieved from the national breast cancer registry. Data regarding lymphedema treatment and seroma aspirations were retrieved from local treatment codes. RESULTS: In total 1822 patients were included of which 291 developed lymphedema. Multivariate cox regression analysis showed that seroma was an independent risk factor (HR 1.92 CI 1.30–2.85, p = 0.001). Other independent risk factors were lymphadenectomy, radiation therapy, chemotherapy, BMI above 30, total lymph nodes removed above 15 and higher number of metastatic lymph nodes. CONCLUSIONS: Postoperative seroma doubles the risk of developing lymphedema. Future studies should examine if seroma reducing measures will lead to lower risk of lymphedema.

BACKGROUND: Lymphatic vessel density and lymphovascular invasion are commonly assessed to identify the clinicopathological outcomes in breast cancer. However, the prognostic values of them on patients' survival are still uncertain. METHODS: Databases of PubMed, Embase, and Web of Science were searched from inception up to 30 June 2016. The hazard ratio with its 95% confidence interval was used to determine the prognostic effects of lymphatic vessel density and lymphovascular invasion on disease-free survival and overall survival in breast cancer. RESULTS: Nineteen studies, involving 4215 participants, were included in this study. With the combination of the results of lymphatic vessel density, the pooled hazard ratios and 95% confidence intervals were 2.02 (1.69–2.40) for disease-free survival and 2.88 (2.07–4.01) for overall survival, respectively. For lymphovascular invasion study, the pooled hazard ratios and 95% confidence intervals were 1.81 (1.57–2.08) for disease-free survival and 1.64 (1.43–1.87) for overall survival, respectively. In addition, 29.56% (827/2798) of participants presented with lymphovascular invasion in total. CONCLUSIONS: Our study demonstrates that lymphatic vessel density and lymphovascular invasion can predict poor prognosis in breast cancer. Standardized assessments of lymphatic vessel density and lymphovascular invasion are needed.