Stem cell saviors

Stem cell saviors. By removing adult stem cells from mouse bone marrow and injecting them into a region of myocardial damage, researchers rescued up to 37% of the lost heart function.

Infarction occurs when a coronary artery becomes blocked. This blockage cuts off the supply of oxygen to the cardiac muscle and leads to scarring and loss of muscle function. If more than 40% of this function is lost, the patient’s prognosis is poor and death is likely. Thus, it is imperative that muscle function be restored as quickly as possible.

One potential way of repairing muscle function is to replace the damaged tissue with healthy tissue. But which tissue does one use? Early studies transplanted fetal or adult cardiac muscle cells, adult skeletal muscle cells, or satellite cells, but the transplants failed to regenerate myocardial function. These tissues, regardless of their ability to differentiate in vitro, did not appear to possess the plasticity required in vivo. Two researchers, however, reporting at the IBC Drug Discovery Technology 2001 conference in Boston, tried a different tack.

Working with mice, Piero Anversa of New York Medical College (Valhalla, NY) and Donald Orlic of the National Human Genome Research Institute (Bethesda, MD) directly injected adult stem cells from bone marrow into healthy myocardial tissue that surrounded infarcted tissue. Within 7–11 days, the stem cells migrated to the damaged area and began to grow and differentiate into cardiomyocytes, vascular endothelia, and smooth muscle cells. This development of new muscle tissue and blood vessels led to a recovery of up to 37% of the lost cardiac function.

The researchers are excited by the potential benefits of their experiments. Treatment with autologous stem cells would eliminate problems of immunologic rejection. Adult stem cells from bone marrow could be enriched in culture and injected directly into the damaged area without surgery. And cell therapy would reduce both the need for heart transplantation and the costs of treatment. The researchers are also hopeful that this technology can be extended to infarcted tissues of the kidneys, intestines, and brain.