BACKGROUND: Endothelial progenitor cells (EPCs) have been assumed to maintain vascular endothelial integrity, so the present study investigated whether the functional capacity of EPCs correlates with endothelial function in healthy young subjects, as has been confirmed in aged subjects with atherosclerotic disease. METHODS AND RESULTS: EPCs in 41 healthy, young male nonsmokers (age 33.1 +/-3.9 years, mean +/- SD) were characterized. The correlation between flow-mediated vasodilation (FMD) and the number of EPCs or the plasma concentrations of growth factors, such as vascular endothelial growth factor, did not reach statistical significance. However, FMD was significantly correlated with the EPC differentiation index, defined as the ratio of the number of EPCs to the total number of adherent cells (r=0.391, P=0.011) and the abundance of endothelial nitric oxide synthase mRNA (r=0.340, P=0.030). CONCLUSIONS: In healthy young men, despite a lack of correlation of the number or colony counts of EPCs, the ability of circulating progenitor cells to differentiate into an endothelial lineage is closely correlated with endothelial function. This cell function assay may serve as a novel biomarker for vascular function in healthy subjects in the pre-atherosclerotic stage.
BACKGROUND: Endothelial progenitor cells (EPCs) have been assumed to maintain vascular endothelial integrity, so the present study investigated whether the functional capacity of EPCs correlates with endothelial function in healthy young subjects, as has been confirmed in aged subjects with atherosclerotic disease. METHODS AND RESULTS: EPCs in 41 healthy, young male nonsmokers (age 33.1 +/-3.9 years, mean +/- SD) were characterized. The correlation between flow-mediated vasodilation (FMD) and the number of EPCs or the plasma concentrations of growth factors, such as vascular endothelial growth factor, did not reach statistical significance. However, FMD was significantly correlated with the EPC differentiation index, defined as the ratio of the number of EPCs to the total number of adherent cells (r=0.391, P=0.011) and the abundance of endothelial nitric oxide synthase mRNA (r=0.340, P=0.030). CONCLUSIONS: In healthy young men, despite a lack of correlation of the number or colony counts of EPCs, the ability of circulating progenitor cells to differentiate into an endothelial lineage is closely correlated with endothelial function. This cell function assay may serve as a novel biomarker for vascular function in healthy subjects in the pre-atherosclerotic stage.