Effects of toll-like receptor-4 gene polymorphisms on soluble P-selectin and von Willebrand factor levels in hypercholesterolemic patients.

Toll-like receptor-4 (TLR-4) gene polymorphisms have been associated with a lower risk of atherosclerosis. High levels of soluble P-selectin (sP-selectin) and von Willebrand factor predict an increased risk for cardiovascular events and correlate to atherosclerotic risk factors. The relationship between these markers and TLR-4 gene polymorphisms was evaluated in a cohort of consecutive hypercholesterolemic outpatients. TLR-4 gene polymorphisms were detected in 48 out of 330 (14%) patients with hypercholesterolemia. Lipid and inflammatory markers, sP-selectin and von Willebrand were evaluated in carriers and in 96 (ratio 2:1 to cases) age- and sex-matched TLR-4 wild-type patients randomly selected from the same population. A cohort of normocholesterolemic outpatients (n = 262) served as the control group. sP-selectin was sensibly lower in carriers of TLR-4 variants as compared to wild-types and controls (89 ng/ml vs. 162 ng/ml and 163 ng/dl, respectively, p = 0.0001). Similarly, carriers showed lower von Willebrand factor values (683 mU/ml) than wild-types (910 mU/ml; p = 0.001). In multivariate analysis, TLR-4 gene polymorphisms were positively associated with sP-selectin, whereas the relationship with von Willebrand factor was no longer significant. HMG-CoA reductase inhibitors reduced sP-selectin and von Willebrand factor levels independently of TLR-4 gene variants. Plasma concentrations of these markers, however, remained lower in carriers of TLR-4 gene polymorphisms even after cholesterol lowering. In conclusion, carriership of Asp299 and Thr399Ile TLR-4 gene polymorphisms is associated with lower levels of sP-selectin and von Willebrand factor among hypercholesterolemic patients. While the underlying mechanisms remain to be investigated, such an association may indicate a protective effect of TLR-4 variants for atherosclerosis.

Soluble thrombomodulin and vascular adhesion molecule-1 are associated to leptin plasma levels in obese women.

Recent studies have suggested that leptin, a plasma protein secreted by adipocytes, may play a role in artherothrombosis. In this study, we tested the hypothesis that leptin contributes to in vivo endothelial dysfunction in obese subjects. A cross-sectional comparison of plasma leptin, soluble thrombomodulin (sTM) and soluble vascular adhesion molecule-1 (VCAM-1) was carried out in 35 obese women (age 48+/-13) selected with a body mass index (BMI) > or =30kg/m(2) and 25 normal weight women (age 50+/-11, BMI < 25). An additional study was conducted to determine the short-term effects of weight loss induced by caloric restriction. Plasma levels of leptin, sTM and sVCAM-1 were measured before and after weight loss. Obese women had higher levels of leptin (35+/-22 versus 22+/-19, P<0.01), sTM (4.8+/-1.8 versus 1.9+/-1.5, P<0.001) and sVCAM-1 (726+/-109 versus 583+/-50, P<0.001) than non-obese women. sTM and sVCAM-1 concentrations had a positive correlation with BMI (sTM, r=0.70, P<0.001; sVCAM-1, r=0.60, P<0.001), waist circumference (sTM, r=0.66, P<0.001; sVCAM-1, r=0.37, P<0.01) and leptin levels (sTM, r=0.53, P<0.001; sVCAM-1, r=0.42, P<0.005). At multiple regression analysis leptin predicted sTM and sVCAM-1 independently of obesity measures and other covariates. Twenty-nine obese patients who completed the program of weight reduction showed a significant decrease in leptin, sTM, and sVCAM-1 levels. The magnitude of decrease of sTM and sVCAM-1 was related to the magnitude of reduction in leptin levels. Therefore, our results show that obesity is associated with enhanced levels of atherosclerosis markers. These abnormalities are related to abdominal obesity possibly mediated by leptin levels, and are reversible with weight loss.

Circulating leptin is associated with oxidized LDL in postmenopausal women.

Recently, leptin has been suggested as a possible cause of atherosclerotic disease. In the present study, we have investigated in postmenopausal women (n = 60; age: 52 +/- 13) the relationship between circulating levels of leptin, oxidized LDL (Ox-LDL) and other biochemical and anthropometric variables of atherosclerotic risk. In addition, we have evaluated soluble thrombomodulin (sTM) as a marker of endothelial damage. An additional study was conducted in a subgroup of obese subjects to determine the short-term effects of weight loss on selected variables. Ox-LDL showed a positive correlation with leptin circulating levels (r = 0.65, P < 0.0001). A significant association was also found between Ox-LDL and body mass index (r = 0.69, P < 0.0001), waist-to-hip ratio (r = 0.50, P < 0.0001), insulin levels (r = 0.65, P < 0.0001), HOMA index (r = 0.55, p < 0.0001) and sTM (r = 0.74, P < 0.0001) levels. After multivariate regression analysis leptin was still related to Ox-LDL levels (P = 0.007). In obese women who completed the program of weight reduction, leptin changes persisted as a significant predictor of plasma changes in Ox-LDL levels. These findings suggested a novel link between leptin and Ox-LDL, possibly involved in atherosclerotic disease.

Differential association between human prostacyclin receptor polymorphisms and the development of venous thrombosis and intimal hyperplasia: a clinical biomarker study.

OBJECTIVE AND METHODS: The role of prostacyclin in the development of venous thrombosis and vascular dysfunction in humans is unclear. In patients with deep vein thrombosis (DVT, n=34) and controls (matched for age, sex, indexes of systemic inflammation and metabolic status, n=20), we studied (i) differences on systemic markers of vascular disease and platelet activation and (ii) the influence of prostacyclin receptor gene (PTGIR) polymorphisms. MAIN RESULTS: Enhanced levels of urinary 11-dehydro-thromboxane (TX)B2 and plasma [soluble(s)] P-selectin, mostly platelet derived, were detected in DVT patients, whereas plasma von Willebrand factor levels and intima-media thickness of the common carotid arteries were not significantly different. In all patients' cohorts, we identified five PTGIR polymorphisms (three nonsynonymous: P226T, R212C, V196L; two synonymous: V53V, S328S). In the four individuals carriers of R212C polymorphism (three in DVT, one in controls), intima-media thickness values were significantly (P=0.0043) higher than those detected in individuals of all cohorts [1.68+/-0.38, 1.55 (1.4-2.2) vs. 1.05+/-0.33, 1.08 (0.01-1.68) mm, respectively, mean+/-SD, median (range)]. Moreover, enhanced sP-selectin and 11-dehydro-TXB2, in DVT versus controls, were statistically significant only in carriers of both synonymous PTGIR polymorphisms V53V/S328S. Only the PTGIR mutant R212C was dysfunctional when examined in an in vitro overexpression system. CONCLUSION: Our results suggest a propensity of enhanced platelet activation in DVT patients with PTGIR polymorphisms V53V/S328S. Moreover, we identified a dysfunctional PTGIR polymorphism (R212C) associated with intimal hyperplasia.

Reduced thromboxane biosynthesis in carriers of toll-like receptor 4 polymorphisms in vivo.

The recent demonstration that platelets express a functional toll-like receptor 4 (TLR4) prompted us to explore the influence of TLR4 polymorphisms (Asp299Gly alone or in combination with Thr399Ile) on thromboxane A(2) (TXA(2)) biosynthesis in vivo. In 17 subjects with TLR4 polymorphisms versus 17 wild type (untreated with aspirin, matched for age, sex, and cardiovascular risk factors), intima-media thickness in the common carotid arteries was significantly lower. Average urinary excretion of 11-dehydro-TXB(2), an index of systemic biosynthesis of TX, was significantly reduced by 65%. The urinary excretion of 2,3-dinor-6-keto-prostaglandin F(1alpha), an index of systemic biosynthesis of prostacyclin, was marginally depressed but the prostacyclin/TXA(2) biosynthesis ratio was significantly higher than in wild type. Selective inhibition of cyclooxygenase 2-dependent prostacyclin (by rofecoxib or etoricoxib) was associated with increased urinary excretion of 11-dehydro-TXB(2) in carriers of TLR4 polymorphisms, but not in wild-type, suggesting a restrainable effect of prostacyclin on platelet function in vivo in this setting. Reduced TXA(2) biosynthesis may contribute to the protective cardiovascular phenotype of TLR4 polymorphisms.