Chipping away at the surface of the endothelial progenitor cell (EPC) mystery

Abstract

Ever since Asahara et al published their seminal report describing “putative progenitor endothelial cells“ in 1997 [1], the idea of circulating cells that can replenish dysfunctional endothelium and promote angiogenesis has captured the imagination of cardiovascular researchers. In the following years, these cells were widely referred to as “endothelial progenitor cells” or “EPCs” and the adjective “putative” that the authors had astutely used in the initial report was dropped. Numerous in vitro and in vivo studies were subsequently conducted to elucidate the role of these cells in the pathogenesis of cardiovascular disease and to investigate their therapeutic potential. This resulted in roughly 1000 publications using the expression “endothelial progenitor cells” within a decade of the initial 1997 publication, and by now this number has grown to over 2500. Most studies have found that the number of circulating EPCs is reduced in patients with known cardiovascular risk factors or established cardiovascular disease. This has lead to the notion that circulating EPCs may be required to maintain a healthy vasculature.