The inability to repair these vessels may increase a person's chances of developing atherosclerosis--a common artery disease that can lead to heart attack, stroke, and other problems.

Stem cells are typically found in the center of a person's bones--an area known as the marrow. Unlike most cells in the body, stem cells are capABLe of becoming other cell types as needed.

In the new study, Dr. Pascal J. Goldschmidt and colleagues from Duke University in Durham, North Carolina treated mice that were designed to develop atherosclerosis with stem cells taken from either young or old mice.

Treatment with stem cells from young mICE stopped the development of artery disease in the test animals. Moreover, mice that received the cells showed much less disease than those did that didn't. Further testing revealed that the stem cells actually inserted themselves into the animal's own arteries.

In contrast, treatment with stem cells from older mice was "much less effective" in preventing atherosclerosis, the authors report. This suggests that stem cells capable of repairing blood vessels decrease with age.

This study "opens a completely new dimension in atherosclerosis," Goldschmidt told Reuters health. The development of treatments that stimulate the marrow to produce repair cells could be useful for older patients with atherosclerosis, he added.

SOURCE: Circulation: Journal of the American Heart Association July 29 2003