Human umbilical cord blood cells and myocardial infarction: Novel ways to treat an old problem.

Myocardial infarction and its consequences such as congestive heart failure continue to be a major cause of death in Western societies despite therapeutic advances made in recent years. A growing body of evidence indicates that cell-based strategies might have promising therapeutic potentials for cardiac revascularization and the restoration of cardiac function. In that respect, several recent experimental studies have demonstrated varying degrees of cardiac regeneration using different stem cell populations such as embryonic stem cells, skeletal myoblasts, hematopoietic stem cells, endothelial progenitor cells, and mesenchymal stem cells [1,2]. Similarly, our group has detected cardiac regeneration by cells of noncardiac origin in biopsies from the hearts of male patients that had undergone sex-mismatched cardiac transplantation [3]. Furthermore, first data from nonrandomized phase I clinical trials for treatment of acute myocardial infarction or chronic ischemic heart failure have emerged, the majority of which show improvements of clinical symptoms, left-ventricular function, and myocardial perfusion following transplantation of total bone marrow cells, bonemarrow-derived mononuclear cells, or peripheral bloodderived stem cells [1,2]. However, there is an ongoing controversy about the cellular source with the highest potential for cardiovascular regeneration.