Cardiovascular disease: potential impact of stem cell therapy.

Atherosclerotic vascular disease becomes a clinical problem when there is sufficient atherosclerotic plaque burden and/or endothelial dysfunction to cause a limitation of nutrient blood flow to tissues. However, once myocardial infarction has occurred, there is little, if any, way to stimulate the growth of new blood vessels or cardiac muscle to replace that which has been lost. The potential use of hematopoietic stem cells (HSCs) to treat cardiovascular disease has recently been suggested from preclinical and clinical studies. HSCs are precursors of all the blood cells, but they may also give rise to cells of the vascular system, endothelial cells in the form of endothelial progenitor cells (EPCs). Clinical trials have been conducted in patients with either acute myocardial infarction or limb ischemia to determine the initial effectiveness and safety of this treatment approach. These studies demonstrated the potential clinical effectiveness of this stem cell approach to the treatment of patients with acute myocardial ischemia and limb ischemia. Today, more preclinical studies are planned to elucidate the mechanism by which transplanted stem cells can home and differentiate into these endothelial cells and cardiac muscle cells. At the same time, new clinical trials are planned to evaluate both chronic, stable as well as acute myocardial ischemia and limb ischemia with CD34+ and CD133+ stem cells, as well as with further selected EPCs and mesenchymal stem cells.