In experiments with mice and rats, the so-called stem cells grew into new muscle and blood vessels. So far, the treatment is limited to short-term experiments. But doctors said that if the approach continues to work, testing on humans could begin within three years. The idea is to harness a patient's own restorative powers to reverse the damage done by heart attacks, a leading killer throughout the industrialized world. The two new studies involve adult stem cells taken from bone marrow.
Stem cells are the body's building blocks for all types of tissue.
In recent years, research has increasingly shown that adult stem cells are remarkably adaptable and can repair disease damage. Other scientists who did not participate in the studies said they demonstrate the body's remarkable flexibility in how it responds to disease and injury. A heart attack occurs when a blockage in coronary arteries reduces blood supply to the heart muscle, suffocating cells. Death typically results if more than 40 percent of the left ventricle, the heart's main pumping chamber, is damaged. Nor does the damage necessarily end there.