Endothelial progenitor cells and abdominal aortic aneurysms.

Endothelial progenitor cells (EPCs) are a population of circulating stem cells that hone in to sites of vascular injury where they undergo differentiation to become incorporated into damaged tissue. The aim of this study was to enumerate EPCs in patients with abdominal aortic aneurysms (AAA). CD133(+) peripheral blood mononuclear cells were immunomagnetically selected and CD34/CD133 was used as a marker of EPCs. EPCs were detected using flow cytometry. AAA patients had significantly higher levels of circulating EPCs than age-matched controls (2.43% vs. 1.25% of all events, P = 0.008). The role and function of EPCs in AAA remain to be determined, but their implication with angiogenesis may represent one plausible mechanism.