Endothelial progenitor cells and endothelial microparticles are independent predictors of endothelial function.

OBJECTIVE:To examine the degree of microvascular endothelial dysfunction in relation to classical cardiovascular risk factors, arterial stiffness, and numbers of circulating endothelial progenitor cells (EPCs) and endothelial microparticles (EMPs), in obese and normal-weight children. STUDY DESIGN:Cross-sectional study with 57 obese (15.2±1.4 years) and 30 normal-weight children (15.4±1.5 years). The principal outcome was microvascular endothelial function measured with peripheral arterial tonometry. Fasting blood samples were taken for biochemical analysis and EMPs (CD31+/CD42b- particles) and EPCs (CD34+/KDR+/CD45dim/- cells) flow cytometry. Characteristics between groups were compared by use of the appropriate independent samples test; a stepwise multiple regression analysis was used to determine independent predictors of microvascular endothelial function. RESULTS:Microvascular endothelial function was significantly impaired in obese children and inversely correlated with body mass index Z scores (r=-0.249; P=.021) and systolic blood pressure (r=-0.307; P=.004). The number of EPCs was significantly lower in obese children and correlated with endothelial function (r=0.250; P=.022), and the number of EMPs was significantly greater in obese children and correlated inversely with endothelial function (r=-0.255; P=.021). Multivariate analysis revealed that systolic blood pressure and numbers of circulating EPCs and EMPs are important determinants of endothelial function. CONCLUSION:Obese children demonstrate impaired endothelial microvascular function, increased arterial stiffness, fewer EPCs, and more EMPs. Besides systolic blood pressure, EPC and EMP counts independently predict the presence of microvascular endothelial dysfunction.