Experimental studies suggested that intravascular or intramyocardial administration of bone-marrow-derived progenitor cells or blood-derived progenitor cells may contribute to functional regeneration of the infarcted
myocardium and enhance neovascularization of ischemic myocardium. Initial clinical studies demonstrated that intracoronary infusion of progenitor cells is feasible and may beneficially affect left ventricular contractile recovery or infarct size in patients with acute myocardial infarction. Nevertheless, some trials have shown that conflicting results and uncertainties remain regarding mechanisms of action and possible ways to improve clinical impact of stem cells in cardiac repair. This paper reviews pivotal phase I and II randomized clinical trials and their limitations, discusses key points in the design of future trials. Recently it has been shown that adipose tissue contains population of adult multipotent mesenchymal stem cells and endothelial progenitor cells. In cell culture conditions they have extensive proliferative capacity and are able to differentiate into several lineages, including endothelial cells, smooth muscle cells and cardiomyocytes. The similarities between stem cells extracted from the bone marrow and the adipose tissue suggest the potential for the adipose tissue to act as an alternative, and perhaps preferable, cell source for repairing damaged tissues, such as the ischemic or infarcted heart.