Leptin and EPCs in Arterial Injury

Abstract

See related article, pages 536–544 Endothelial progenitor cells (EPCs) were introduced to a broad scientific readership in 1997 by Asahara et al, who demonstrated that CD34+ cells from the peripheral blood can adopt an endothelial cell-like phenotype in vitro.1 This culture-modified cell type (subsequently also termed endothelial outgrowth cells) improved ischemic neovascularization after intravenous transfusion.2 The prospect of ameliorating tissue ischemia by ex vivo–expanded autologous angioblasts resulted in extensive research activities, including the therapeutic application in patients with myocardial ischemia.3 However, the results are still conflicting, which is at least partially attributable to the fact that EPCs comprise a heterogenous pool of subpopulations originating from distinct sources and displaying diverse phenotypes.4 For instance, the common characterization of EPCs as CD34+CD133+VEGF-R2+ by flow cytometry has been recently questioned in different studies showing that only CD133−CD45− cells differentiate into endothelial cells.5,6 Early outgrowth of endothelial-like cells from mononuclear cells cultured for 5 to 7 days in the presence of endothelial growth factors represent a monocyte-like subtype with low proliferative capacity secreting high …