It's the latest news from a fast-growing area of biomedical research based on the discovery that even mature organs contain stem cells that can multiply to grow new tissue. Just last year, for example, scientists reported that the brain is capable of growing new nerve cells -- a finding that upset the century-old belief that the number of cells in the adult brain could not be increased.
The new discovery comes from a research group at New York Medical College that has led the study of heart cell regeneration. Last year, these researchers said they had found evidence of new growth in the area where a heart attack had caused muscle damage.That finding is confirmed by study of an unusual group of patients, men who received heart transplants from women, says a report in the Jan. 3 issue of the New England Journal of Medicine. The chromosomes in female cells differ from those in male cells, so the researchers could easily tell whether cells from the body of the man who received the transplant had migrated into the heart and divided to form new cells.
A group led by Dr. Piero Anversa, director of the cardiovascular research institute at New York Medical College, looked at the hearts of eight men who received transplants from women and who died of unrelated causes. They found that not only were there male cells in the female hearts but also that those cells had divided to form new tissue.
Anversa is cautious about interpreting the result. "We have identified cells with stem cell characteristics," he says. "This points to the possibility that cardiac stem cells may be present. First we need to know if we do have stem cells. When these cells are better characterized, we could suggest that there is a mobilization of primitive cells of the heart to reach areas where damage has occurred and promote repair."
Anversa's group is working to extend the findings. He says he cannot be specific because the new work is awaiting scientific publication, but he does say that "we have a number of assessments going on in animals and humans to understand what role these primitive [cells] play."
The ultimate goal, Anversa says, is to "exploit our fantasy, that we will be able to utilize whatever is in the heart to mobilize stem cells."
The New York group is not the only one working on realizing that dream, says Dr. Roberto Bolli, chief of cardiology at the University of Louisville and author of an accompanying editorial. "The field has exploded in the last year or two," he says.
The challenge now is to understand the mechanism by which new heart cells are generated, Bolli says. "If we can identify the mechanism, it should be possible to exploit it to regenerate tissue in heart failure and other conditions," he says. "Once we discover which cells are responsible, then we need to learn how we can do it."
What To Do
The prospects of heart repair from this basic research is years away, so it is still essential to follow the rules about a prudent diet, low in fat and high in fiber, about physical activity, and other measures that prevent damage in the first place.
All you need to know about heart health is available from the American Heart Association.
To learn more about stem cells, visit the