Cardiac Progenitor Cells

Abstract

See related article, pages 1090–1092 In the last few years we have witnessed one of most extraordinary revolutions in cardiovascular medicine, namely, an explosion of basic and clinical studies that support the notion that the diseased heart can be repaired by administration of stem cells, resulting in formation of functional new myocytes and vessels. Although the mechanism by which cell therapy improves cardiac function and anatomy remains uncertain, translation of basic findings to the clinical setting is proceeding at a feverish pace.1 A multitude of small, mostly nonrandomized clinical studies have reported improvement in cardiac perfusion and function after therapy with various cell types in patients with acute myocardial infarction or chronic ischemic cardiomyopathy.1 Larger, randomized, double-blinded studies will be reported soon; if they confirm the salubrious effects of cell-based therapies observed in the initial trials, our management of acute myocardial infarction and heart failure will change dramatically. One of the most important and unresolved issues in this scenario is the identity of the ideal cell for myocardial reconstitution. Although most of the clinical studies reported to date have used bone marrow– or skeletal muscle–derived cells, a host of other cells are being investigated in the experimental laboratory. Among these, resident cardiac stem cells (CSCs), discovered by Anversa’s group in 2003,2 hold great promise. In their initial report,2 Beltrami et al identified a lin−/c-kit+ population of primitive cells that can be clonally expanded, differentiates into cardiac myocytes, smooth muscle cells, and endothelial cells in vitro, and is able to reconstitute infarcted myocardium in vivo. It is of translational interest that these cells can effect cardiac repair when delivered via the intravascular route.3 CSCs have also been shown to be present in the human heart, where they give rise to new myocytes in patients with …