Objectives: To assess whether circulating endothelial progenitor cells (CEPCs) can be considered as a cardiovascular risk marker before event has occurred, that is less firmly established than in clinically overt atherosclerosis.
Methods: Number of CD34+KDR+ cell number per ml blood was measured by flow cytometry in 84 untreated subjects without cardiovascular disease. Atherosclerotic plaque was detected by ultrasound in carotid, abdominal aortic and femoral sites and the number of sites affected by plaque among these three sites was counted as 0, 1, 2 or 3. Additionally, intima-media thickness (IMT) was measured by computerized ultrasound imaging of both common carotid segments.
Results: CD34+KDR+ cell number decreased by 48, 29 or 30% in the presence of carotid, aortic or femoral plaque (p<0.001, 0.05, 0.05, respectively) as compared to the absence of plaque and by 70% in the presence of three sites affected with plaque as compared with 0 site with plaque (p<0.01) but did not change with increasing IMT tertiles. Adjustment for Framingham risk score, that was also associated with decreased CD34+KDR+ cell number (p<0.001), made CD34+KDR+ cell number associations with plaque insignificant, except at the carotid site (p<0.01).
Conclusions: Reduced CEPC number may participate to preclinical stage of atherosclerosis and provide additional information to traditional risk factors as regards global risk assessment.