Clinical Hemorheology and Microcirculation

High-density lipoprotein (HDL) plays an important role not only in protecting against atherosclerosis but also in innate immunity. Several lines of evidence showed that HDL could ameliorate the toxic effects of endotoxin or lipopolysaccharide (LPS). In this study, we examined whether HDL could inhibit LPS-induced leukocyte adhesion on endothelial cells in rats. Normal HDL and acute-phase HDL (AP-HDL) were purified from plasma of hamsters that received normal saline and LPS injection, respectively. Wistar rats were given LPS injection and the number of leukocytes adhering to endothelial cells of the mesenteric venules was determined using intravital fluorescence videomicroscopy. Intravenous injection of LPS enhanced leukocyte adhesion to the mesenteric venules. However, when LPS was preincubated with normal HDL, leukocyte adhesion on endothelial cells in response to LPS was significantly attenuated in a dose-dependent manner. AP-HDL was also able to significantly decrease LPS-induced leukocyte adhesion on endothelial cells. It appeared to be more effective than normal HDL since lower concentrations were required. This inhibitory effect of HDL was not due to HDL itself but it requires preincubation of HDL with LPS. When HDL was separated into protein and lipid fractions, it was found that lipid-free apoHDL was able to significantly inhibit LPS-induced leukocyte adhesion, whereas lipid component of HDL had no effect. In conclusion, HDL, both normal and acute-phase, could inhibit an inflammatory effect of LPS on endothelial cells in vivo. AP-HDL was more potent than normal HDL in inhibiting LPS-induced leukocyte adhesion, and this effect was attributed to the protein component of HDL.

Background: Conflicting results were reported about the efficacy of vitamin E (E) treatment in porphyria cutanea tarda (PCT). We conducted a study in PCT patients to investigate whether E treatment has any additional beneficial effects compared with phlebotomy (P) treatment alone on rheological and oxidative stress parameters. Methods: Twenty three patients with sporadic PCT in clinical remission and 10 healthy control patients were studied. All patients were treated with P prior to the study until clinical remission was achieved. Baseline routine laboratory [blood glucose, serum lipids, C-reactive protein (CRP), iron metabolism indices, liver function tests], oxidative stress [serum thiobarbituric acid reactive substances (TBARS), plasma H-donor activity, plasma free SH-groups, erythrocyte glutathion peroxidase activity] and rheological parameters (whole blood and plasma viscosity, cell transit time, clogging rate) were measured in both groups. Then all PCT patients received E (tocopherol acetate) 200 mg/day for 8 weeks and at the end of treatment measurements identical to those performed at baseline were repeated. Results: Increased urine uroporphyrin, serum CRP, TBARS concentrations, whole blood and plasma viscosity and decreased plasma H-donor activity, free SH-group level, erythrocyte glutathione peroxidase activity were detected in PCT patients treated with P alone compared with control group consistent with residual oxidative stress in PCT patients. E treatment decreased urine uroporphyrin and serum TBARS concentrations; increased plasma H-donor activity and did not influence whole blood and plasma viscosity compared with P treatment alone. Conclusions: E treatment reduced the residual oxidative stress and did not influence increased plasma and whole blood viscosity present in PCT patients receiving P treatment prior to clinical remission.

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are the most commonly used cholesterol-lowering drugs, with recent clinical trends usually aimed at achieving the lowest possible plasma cholesterol levels. Although the effects of increased plasma cholesterol have been previously reported, it is not obvious how very low plasma cholesterol levels would affect membrane composition and the deformability of red blood cells (RBC). The present study investigated the effects of hypocholesterolemia achieved by atorvastatin therapy on RBC membrane and mechanical properties in guinea pigs fed a normal diet. Two groups of animals were used (atorvastatin-treated, n=12; control n=12), and atorvastatin given orally in isotonic phosphate-buffered saline (PBS) at a dose of 20 mg/kg/day for a 21-day period. Our results indicate that the atorvastatin-treated group had significantly lower plasma total cholesterol (17.42±1.70 mg/dl), low-density lipoprotein cholesterol (5.25±2.22 mg/dl) and triglycerides (42.60±3.78 mg/dl) than the control group (34.08±1.72, 21.17±1.41 and 60.64±2.43 mg/dl, respectively). In addition, membrane cholesterol content was lower (p<0.0001) and phospholipid content higher (p<0.0001) in the atorvastatin-treated group, thus decreasing the cholesterol to phospholipid ratio; a significant enhancement in sodium-potassium-ATPase activity also occurred. However, in spite the marked changes of plasma and RBC membrane composition, there was no change of RBC deformability. Note that although our results indicate no adverse rheological alterations, extension of our findings to humans requires caution.

Objective: To investigate the extent to which B-flow and B-flow with 3D postprocessing and speckle reduction imaging (SRI) have advantages in appraising the morphology of a high-grade stenosis of the internal carotid artery (ICA) for preinterventional planning and for postinterventional ultrasonographic follow-up. Materials/methods: A comparative appraisal of flow with CCDS, power Doppler, B-flow and 3D B-Flow with SRI were carried out prospectively in 50 patients with >70% stenosis according to NASCET criteria in contrast medium-enhanced MRA before and after the intervention. After stenting of the internal carotid artery (ICA), i.a. digital substraction angiography (DSA) served as an additional reference method. Results: In >70% ICA stenosis, simultaneous imaging of the pre-stenotic, intra-stenotic and post-stenotic flow was attained with B-flow in 45/90 cases (90%), with power Doppler in 39/50 cases (78%) and with CCDS in only 31/50 cases (62%). After intervention, a complete detection of flow without overwriting or blooming artifacts was achieved in all 50 patients only by B-flow. The intrastenotic flow (p<0.05) could be better demarcated against the lumen and the vessel wall before the intervention, whereas the flow within the stent could be very much better appraised after the intervention (p<0.01) using 3D postprocessing of B-flow with additional SRI. Re-stenoses with hypoechoic vascular wall changes (3/50 patients) were detected at an early stage using B-flow. Conclusions: B-flow technique with SRI and 3D postprocessing can facilitate the intrastenotic detection of flow in >70% ICA stenosis with fewer flow artifacts. After stenting, the perfused vascular lumen shows less flow artifacts compared with CCDS and power Doppler. In order to elucidate hemodynamic changes, additional Doppler examinations are still necessary.

The upper aerodigestive tract, composed of the oral cavity, the pharynx and the esophagus, is a complex system whose components function in both organ-specific ways as well in serving as a protective barrier against the enzymes which initiate digestion as well as against the mechanical functions which serve to ensure movement of food through the upper aerodigestive tract. Given these diverse functional requirements, the study of the anatomy and physiology of this region are uniquely complex and significantly understudied. The goal of the current study was to develop a simple and reproducible method for the isolation, growth, and maintenance of primary epithelial cells from the oral cavity, the pharynx and the esophagus. In addition, given the increased interest in diseases characterized by a loss of mucosal integrity in these areas which is often accompanied by a diminished wound healing capability, these cells were biochemically characterized with a focus on the components of the extracellular matrix remodeling axis including the activity and inhibition of the matrix metalloproteinases (MMPs).

Recently silver fibers containing compression stockings for the use in patients with chronic venous insufficiency (CVI) were introduced to the market. In order to gain some first insight into the effects of these new fabrics on the cutaneous microcirculation, a double-blind, randomized cross-over trial was performed in 10 healthy volunteers. A 3 days run-in phase preceded the (2×10 days) treatment phases and was used to assess the reproducibility of the primary endpoint, which was the transcutaneous partial oxygen pressure (tcpO₂) measured at a probe temperature of 44°C in the perimalleolar region of the reference leg in supine and dependent leg positions. Coefficients of variation for double measured tcpO₂ values were 4.2% (3.1 SD) and 5.8% (6.0 SD) for the leg in supine and dependent position. The intra-individual comparison of the effects from both treatment phases (value end of treatment – start of treatment) resulted in a negative tcpO₂ net balance for the regular hosiery (−0.93 (2.7 SD) mmHg, supine; −1.1 (3.5 SD) mmHg, dependent) but a positive net balance for the silver fibers containing stockings (0.25 (4.0 SD) mmHg, supine; 1.7 (3.9 SD) mmHg, dependent). The inter-treatment differences were statistically significant for the leg in a dependent position. The trial provides first evidence that interweaving silver threads into regular compression stockings may result in a positive effect regarding the nutritive skin perfusion.

The aim of this study is to investigate the effects of CsA on lymphocyte deformability and oxidant–antioxidant system in peripheral lymphocytes in rats. Female WistarAlbino rats were injected 10 mg/kg/30 days Sandimmun i.p. the control rats were injected 0.9% NaCl. CsA administration caused a significant reduction in the deformability of lymphocytes, and produced a significant increase in peripheral lymphocytes lipid peroxide level and a significant decrease in nitric oxide (NO) level. The activity of superoxide dismutase (SOD) in peripheral lymphocytes did not show significant differences between CsA administrated and control rats. However the total thiol (t-SH) content of lymphocytes was significantly lower in CsA administrated rats. Conlusions. The present data demonstrate that CsA administration increased lipid peroxidation and decreased the NO levels and t-SH contents in the peripheral lymphocytes of rats. This effect was accompanied by a decrease in lymphocytes deformability. These results support the hypothesis that sufficient cellular t-SH concentrations may be important to prevent cyclosporin toxicity, and indicate that disturbances in lymphocytes rheology may be an additional risk factor in the pathogenesis of side effects associated with CsA.

Behçet's disease (BD) is a chronic systemic vasculitis characterized by recurrent oral and genital ulcers, uveitis, and skin lesions. It is also associated with an increased risk of developing thrombosis, although the prothrombotic mechanisms are not clearly defined. The role played by rheological alterations in the development of thrombotic events in BD is not well defined, existing little information on whether erythrocyte deformability (ED) may be involved in this issue. Therefore we aimed to evaluate ED by ektacytometric techniques in a large group of patients with BD in a non-active phase of the disease at sampling and in a well-matched control group, in order to establish a possible association between alterations in ED and the presence of thrombotic events. The patient group comprised 45 patients with BD (22 male, 23 female aged 42±14 years) and the control group comprised 46 healthy volunteers (23 male, 23 female aged 45±13 years). Twelve of the 45 patients with BD had a previous documented history of deep vein thrombosis at least six months before entering the study, and the other 33 did not. Erythrocyte elongation indexes (EI) at the three shear stresses tested (EI12, EI30, EI60) were not statistically different between patients and controls (EI12: P=0.453; EI30: P=0.411; EI60: P=0.403). There were no significant differences in these parameters, either, when patients with and without previous thrombotic events were compared (EI12: P=0.272; EI30: P=0.215; EI60: P=0.171). Our results suggest that ED is not compromised in BD and does not seem to be involved in the development of thrombotic events in these patients.

Several studies had assessed the rheological and haemostatic parameters in both sickle cell anaemia(HbSS) and haemoglobin AA(HbAA) subjects. The effect of the heterogeneous state on these parameters has not been fully determined. Our aim was to assess the haemorheological and haemostatic parameters and there relationship to body mass index in individuals with the sickle cell trait. Fifty eight males (41 HbAA and 17 HbAS) who were neither smokers nor drinkers were studied. Body mass index was calculated as weight in Kg divided by height in m², blood samples were analysed for haematocrit, erythrocyte sedimentation rate, platelets, fibrinogen and factor VII by standard methods. There were no significant differences in the levels of haemostatic and cardiovascular risk factors between the HbAA and HbAS individuals. Fibrinogen correlated positively with BMI (r=0.6014, p=0.0107), systolic blood pressure (r=0.4820, p=0.0570), diastolic blood pressure (r=0.4699, p=0.0570) in HbAS individuals. The body mass index also correlated positively with diastolic blood pressure (r=0.5182, p<0.05), and systolic blood pressure (r=0.6189, p<0.01). Positive associations were also found between fibrinogen and body mass index (r=0.5012, p=0.0008), and fibrinogen and haematocrit (r=0.3696, r=0.0174) respectively in HbAA subjects. We conclude that the lack of significant difference in both haemorheological and cardiovascular risk factors in HbAS and HbAA subjects has further supported the observation that HbAS is a benign condition under physiological settings. Also the positive associations of fibrinogen with other cardiovascular risk factors have further underscored the central role of fibrinogen as an independent risk factors in the development of cardiovascular diseases.