Gender differences in circulating endothelial progenitor cell colony-forming capacity and migratory activity in middle-aged adults.

Middle-aged women have a lower prevalence and incidence of cardiovascular events compared with men. The mechanisms responsible for this gender-specific difference are unclear. Numeric and functional impairments of bone marrow-derived circulating endothelial progenitor cells (EPCs) are associated with increased cardiovascular and cerebrovascular morbidity and mortality. It is currently unknown whether there are gender-related differences in EPC number and function in middle-aged adults. We tested the hypothesis that EPCs isolated from middle-aged women demonstrate greater colony-forming capacity and migratory activity compared with men of similar age. Peripheral blood samples were collected from 50 sedentary adults, 25 men (59 +/- 1 years of age) and 25 women (58 +/- 1 years of age). Mononuclear cells were isolated and preplated for 2 days, and nonadherent cells were further cultured for 7 days to determine EPC colony-forming units. Migratory activity of EPCs was determined using a modified Boyden chamber. The number of EPC colony-forming units was significantly higher (approximately 150%) in samples collected from women (16 +/- 3) compared with that collected from men (7 +/- 1). In addition, EPC migration (relative fluorescent units) was approximately 40% greater in women (729 +/- 74) than in men (530 +/- 67). In conclusion, these results demonstrate that EPC colony-forming capacity and migratory activity are higher in middle-aged women than in men.