Introduction. Bone marrow-derived endothelial progenitor cells (EPCs) circulate in the peripheral blood and are involved in endothelial homeostasis and repair.
Aim. The aim of this study was to assess the circulating levels of different EPC phenotypes in overweight men with or without erectile dysfunction (ED). As endothelial dysfunction is considered a necessary link with ED, endothelium-dependent vasodilation and its relation with EPCs were also investigated.
Methods. We studied 30, otherwise healthy, overweight subjects with symptomatic ED for at least 6 months, and 30 age- and weight-matched subjects without ED. Erectile function was assessed by completing the International Index of Erectile Function (IIEF-5), which consists of items 5, 15, 4, 2, and 7 from the full-scale IIEF-15.
Main Outcome Measures. Seven subpopulations of EPCs were determined by flow cytometry on the basis of the surface expression of CD34, CD133, and KDR antigens: CD34+, CD133+, KDR+, CD34+CD133+, CD34+KDR+, CD133+KDR+, and CD34+CD133+KDR+. Endothelium-dependent flow-mediated dilation (FMD) was evaluated in the right brachial artery with a high-resolution ultrasound machine following reactive hyperemia.
Results. CD34+KDR+ cell count was significantly lower in men with ED as compared with men without ED (63.1 ± 4 vs. 92.4 ± 6 cells/106 events, mean ± standard error, P < 0.01). There was a significant direct correlation between circulating CD34+KDR+ cells and the IIEF score (r = 0.44; P = 0.01): men with the severe form of ED presented the lowest level of circulating EPC CD34+KDR+ cells. No significant correlation was found between the circulating levels of the other EPC phenotypes and the IIEF score. There was a significant correlation between CD34+KDR+ cell count and FMD (r = 0.45; P = 0.01), but not between FMD and the other phenotypes.
Conclusions. Circulating levels of CD34+KDR+ EPC are reduced in overweight subjects with ED and correlate with the severity of ED. Other EPC phenotypes are not related to ED, suggesting that the CD34+KDR+ phenotype of EPCs may be preferred in future studies. Esposito K, Ciotola M, Maiorino MI, Giugliano F, Autorino R, De Sio M, Jannini E, Lenzi A, and Giugliano D. Circulating CD34+KDR+ endothelial progenitor cells correlate with erectile function and endothelial function in overweight men. J Sex Med 2009;6:107–114.