Phenotypic Assessment of Endothelial Microparticles in Diabetic and Nondiabetic Men with Erectile Dysfunction

Abstract Introduction Endothelial microparticles (EMPs) may play a role as biomarkers of vascular injury. EMPs are higher in men with diabetes diabetic men with erectile dysfunction (ED) than in nondiabetic potent men. Aim The aim of this study was to quantize different phenotypic circulating EMP levels among diabetic and nondiabetic patients with ED, and to determine whether EMPs are released as a result of activation or apoptosis. Methods We studied 30 type 2 diabetic and 24 nondiabetic subjects with symptomatic ED from at least 6 months, and 20 nondiabetic men without ED matched for age and weight with diabetic and nondiabetic subjects. Erectile function was assessed by completing the International Index of Erectile Function (IEEF)-5, which consists of Items 5, 15, 4, 2, and 7 from the full-scale IIEF-15. A score of 21 or less indicates the presence of ED. Main Outcome Measures EMP levels in plasma were quantified by flow cytometry. Markers for apoptosis (platelet/endothelial cell adhesion molecule 1/CD31 antigen) and activation (E-selectin/CD62E antigen) were compared. Endothelium-dependent flow-mediated dilation (FMD) was evaluated in the right brachial artery with a high-resolution ultrasound machine following reactive hyperemia. Results Diabetic patients were found to have the highest levels of EMP31+; diabetic and nondiabetic men with ED were found to have significantly higher levels of EMP62+ than nondiabetic men without ED. The EMP62/EMP31 ratio, an index of endothelial activation (high ratio) or apoptosis (low ratio), was lowest in diabetic men with ED (0.20). In the whole group of 54 men with ED (diabetic and nondiabetic), there was an inverse correlation between FMD and the number of circulating EMPs (P <0.05). Conclusions The presence of diabetes in subjects with ED is associated with a different pattern of endothelial cell injury. The phenotypic assessment of EMPs in diabetic patients with ED is consistent with increased apoptotic activity.