Circulating endothelial microparticles correlate inversely with endotheilal function in patients with ischemic left ventricular dysfunction

Background: Bone-marrow derived endothelial progenitor cells (CD34+ and VEGFR2(+) KDR+ EPC) and endothelial-derived microparticles (CD 31+Annexin V+, EMP; indicator for endothelial apoptosis) were examined in the peripheral blood of 35 male, clinically stable patients with 3-vessel coronary artery disease (CAD). The patients were divided in 2 groups, those with preserved or normal function (n = 17; EF 65 +/- 6%) and those with reduced left ventricular (LV) function (n = 18; EF 36 +/- 11%). Methods and Results: The number of circulating EPCs was decreased by 25% (P =.07) and the number of EMPs was increased by 109% (P <.05) in patients with LV dysfunction compared with those with normal or preserved LV function. EPCs were positively correlated (r = 0.24 for patients with LV dysfunction and r = 0.28 for patients with preserved LV function) with endothelial function as assessed by flow-mediated vasodilatation. In contrast, EMPs were inversely correlated (r = -0.42 for patients with LV dysfunction and r = -0.49 for patients with preserved LV function). Conclusions: CAD patients with significant LV dysfunction show an increased index of endothelial cell damage. This decrease (or lack of compensatory elevation) of EPCs may result in a reduced potential for repair and thus contribute at least in part to the pathogenesis of endothelial dysfunction.