Adult stem cell therapy for heart failure

Evidence indicates that bone marrow and many other somatic tissues contain pluripotent or multipotent adult stem cells as well as progenitor cells which can differentiate into cells of various phenotypes. Experimental studies strongly suggest that the normal function of the marrow derived adult stem cells is for tissue repair, and that they can be recruited by signals originating from injured tissue, traffic through the circulation and home into the injured site to undergo milieu dependent differentiation in situ. In the heart, these cells may differentiate into cardiomyocytes, vascular cells and scar tissue, thus participating in vasculogenesis, scar maturation and modulation of the remodelling process of the myocardium. To augment such a healing process, cell therapy using such cells, which may be preprogrammed if desired, may have donor cells implanted by direct injection, coronary infusion and, in some cases, by systemic intravenous administration. Improved ventricular function has been reported in myocardial infarct animal models. Although early Phase I clinical trials have been initiated for both autologous myoblast and autologous marrow cell transplants with favourable reported outcomes, the data are still too preliminary to draw definitive conclusions regarding their safety and efficacy. Additional mechanistic and translational preclinical investigations are essential, and well designed clinical studies are required before the great potential of adult stem cell therapy can be fully realised and benefit the vast number of heart failure patients.