Adult stem cell-based therapy for the heart

It is unusual that a research topic generates such broad interest and debate in the scientific and public communities as the study of stem cells in regenerative medicine is doing. The ability to mobilize and activate endogenous stem/progenitor cells in diseased organs or to introduce exogenous stem cells for tissue regeneration/repair may impact many diseases, including those affecting the brain, skeletal muscle, pancreas and heart. The recent reports suggesting that embryonic and adult stem cells can differentiate into cardiomyocytes, vascular smooth muscle cells and endothelial cells have stimulated studies investigating the use of stem cells as reparative therapy for cardiovascular diseases that, despite many recent advances in medical treatment and interventional techniques, still remain major causes of morbidity and mortality. For example, the current therapeutic approaches to treat congestive heart failure merely delay the progression of the disease, thus generating a population of chronically-ill patients. Heart transplantation is the only effective therapy for this otherwise deadly clinical condition. However, the limited number of organs donated is not sufficient to treat all patients who would require a transplant. Consequently, the disabilities of a growing number of people with heart disease will continue to place a heavy burden on an already financially-strained healthcare system, and the socioeconomic costs are incalculable. Cellular therapy for treating these and other heart conditions is a growing field of basic and clinical research. Here, we examine the current basic science that is the foundation of future clinical approaches to adult stem cell therapy for heart diseases, and summarize the results of recent attempts to repair ischemic myocardial damage in humans by transplanting adult cells of bone marrow origin.