Stem cells for the treatment of heart failure

An increasing number of clinical trials are enrolling patients in studies designed to examine the safety and efficacy of autologous stem cells for cardiac repair. Recent reports suggest that most patients receiving autologous cell-based therapies after myocardial infarction, or as a treatment for ischemic cardiomyopathy, benefit from a modest increase in global left ventricular function. Despite a significant amount of variability in efficacy reported among different treatment centers, most studies demonstrate an improvement in the ejection fraction that ranges between 2 and 7% after stem cell treatment. The validation of long-term clinical benefit will first require well-controlled studies in appropriate preclinical animal models to develop procedures that enhance cell retention, integration and viability. This review highlights new developments that will benefit long-term cardiomyocyte survival and function of human cardiovascular progenitors as a prelude to achieving clinically significant outcomes in stem cell therapies for cardiac repair.