Marrow Transplant Grows New Vessels in Legs

Prevents limb amputation in those with circulatory problems

MONDAY, Nov. 18, 2002 (HealthDayNews) -- Doctors have prevented amputations in people with poor circulation in their legs by injecting the patients' own bone marrow into their limbs.

A Japanese research team says the marrow injections helped new blood vessels form in the affected limbs, which had clogged arteries. The team reported the feat today at the American Heart Association's scientific sessions meeting in Chicago.

The team believes it is the first to try the technique, says Dr. Hiroya Masaki of Kansai Medical University in Moriguchi, Japan. It is not only effective but appears very safe. "There are no serious side effects or complications from the technique," he says.

In peripheral artery disease (PAD), deposits build up along the walls of the arteries and reduce blood circulation, especially to the legs and feet. Due to the risk of blood clots, those with PAD have a higher risk of death from stroke and heart attack.

The condition can be painful and, in later stages, it can lead to a lack of blood flow or even gangrene, which triggers the need for amputation of a limb.

Current treatments include medication to prevent blood from clotting or angioplasty, in which a deflated balloon is passed into the narrowed vessel and then inflated to open it up. Surgery can also be done to bypass the diseased vessel portion or to cut out the fatty deposits.

The Japanese researchers tried another approach. They aspirated bone marrow cells from the person's hip bone. They implanted either a patient's own bone marrow cells or saline (as a control treatment) into the calf muscles of 45 patients with peripheral artery disease. Twenty had reduced blood flow in both legs and 25 had it in one leg.

Those who got the bone marrow cell transplants had a "striking" increase in new formation of collateral vessels, as shown on angiography (exam of the blood vessels by X-ray after injecting an opaque substance) and thus improved blood flow, the researchers found.

New vessels were documented in 27 limbs among those who received the bone marrow transplants. New capillary vessel formation was much less in those who got the saline injections.

"Bone marrow cells contain endothelial stem cells and also release growth factors," says Dr. Hiroaki Matsubara of Kansai Medical University, who presented the data today. "The endothelial cells attach to existing capillary cells" and enhance their growth, he says. New capillaries then sprout and provide collateral circulation. Endothelial cells are delicate cells that line arteries.

"It's interesting that they used the person's own bone marrow cells," says Dr. Richard Nesto, chairman of cardiovascular medicine at Lahey Clinic Medical Center in Boston and a spokesman for the American Heart Association.

Over the past several years, Nesto says, there have been many studies using growth factors to encourage blood vessel growth. The Japanese study, however, "is the first I've seen where they inject directly into the muscle itself. Usually they inject into the artery supplying the [smaller] blood vessels."

The technique seems safe and effective, Nesto says. Once perfected, he adds, it would seem feasible the treatment could be a simple outpatient procedure.

What To Do

For more information on peripheral artery disease, try the American Heart Association or the University of California at Davis.

SOURCES: Hiroya Masaki, M.D., Ph.D., Kansai Medical University, Moriguchi, Japan; Hiroaki Matsubara, M.D., Ph.D., Kansai Medical University, Moriguchi, Japan; Richard Nesto, M.D., associate professor, medicine, Harvard Medical School, and chairman, cardiovascular medicine, Lahey Clinic Medical Center, Boston; Nov. 18, 2002, presentation, American Heart Association scientific sessions meeting, Chicago
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