Endothelial Microparticles Correlate with Endothelial Dysfunction in Obese Women

CONTEXT: Cell-derived microparticles are supposed to be involved in atherogenesis. OBJECTIVE: This study aimed to evaluate circulating microparticles in obese women and their relation with anthropometric measures and endothelial dysfunction. DESIGN, SETTING, AND PARTICIPANTS: Forty-one obese [body mass index (BMI) > 30 kg/m(2)] women and 40 normal weight (BMI < 25 kg/m(2)) age-matched women were studied. Flow cytometry was used to assess microparticles by quantification of circulating endothelial microparticles (EMP, CD31+/CD42b-) and platelet microparticles (PMP, CD31+/CD42b+) in peripheral blood; endothelium-dependent flow-mediated vasodilation (FMD) was evaluated in the right brachial artery after reactive hyperemia. RESULTS: Compared with lean women, obese women presented significantly higher numbers of EMP and PMP, and reduced FMD. BMI did not correlate with either EMP (r = 0.02, P = 0.9) or PMP (r = -0.07, P = 0.645), whereas waist-to-hip ratio (WHR) showed significant correlation with both microparticles (r = 0.699, P < 0.001; r = 0.373, P = 0.016, respectively). Both EMP and PMP counts positively correlated with impairment of FMD in obese women. Multivariate analysis correcting for age, anthropometric indices, lipid parameters, and PMP identified EMP as the only independent predictor for impaired endothelial-dependent vasodilation (P = 0.003). CONCLUSIONS: EMP are elevated in obese women and independently involved in the pathogenesis of endothelial dysfunction. WHR is the anthropometric measure more closely related to EMP and endothelial dysfunction.