Endothelial progenitor cells and vascular disease Are they for real

Endothelial progenitor cells (EPCs) were initially described in 1997, though their properties and roles are still being investigated and debated. Their core characteristics were identified as circulating cells displaying a variety of cell surface proteins thought to be endothelial specific, the ability to grow in culture, and the ability to localize and promote vascular growth at sites of ischemia.1 Very soon thereafter, studies suggested an inverse relationship between the number of circulating EPCs and vascular risk factors in patients with stable ischemic heart disease2 and, later, in those with acute or stable stroke.3 Subsequent reports suggested that the use of statins could increase EPC numbers in patients with stable coronary artery disease, though this observation was not confirmed in a larger randomized trial.4 Other data suggested that infusion of EPCs after an acute myocardial infarction could result in improvement in cardiac function and decreased mortality.5 The initial excitement, not surprisingly, prompted numerous investigations on EPCs. However, despite 13 years having passed since the landmark article in Science ,1 and having done further, more detailed, analyses on EPCs, we are still …