Decrease in circulating endothelial progenitor cells in patients with stable coronary artery disease.

T he bone marrow derived endothelial progenitor cells (EPCs) are considered to originate from haematopoietic stem cells, which are positive for CD34. Human CD34 expressing cells (CD34 cells) injected into nude mice and rats undergoing neovascularisation caused by hindlimb ischaemia are incorporated into the neovasculature and express endothelial antigens. We recently reported that transplantation of autologous bone marrow cells, including CD34 cells, improved ischaemia in patients with critical limb ischaemia. Moreover, increased neovascularisation by bone marrow derived CD34 cells was shown to improve cardiac function. Recently, a mobilisation of EPCs into circulation from bone marrow was reported in patients with acute myocardial infarction and acute coronary syndrome, 4 but little is known about the regulation of EPC mobilisation in patients with stable coronary artery disease (CAD). In the present study, we investigated the number of circulating CD34 cells in patients with CAD and the influence of atherosclerotic risk factors on this number.