Stem cells derived from fat may someday be used to provide a "medical bypass," a non-surgical alternative to heart bypass operations for people suffering from narrowed coronary arteries.

Treating coronary artery disease is one of three clinical applications considered most promising for these fat-derived stem cells, at least in the judgment of an expert consensus panel that met yesterday at the International Fat Applied Technology Society meeting here.

Treating peripheral artery disease in the legs and repairing congenital bone deformities and bone injuries are two other applications that should be considered for early clinical experiments, said Dr. Keith March, director of the Indiana Center for Vascular Biology and Medicine at Indiana University School of Medicine, who moderated the session on clinical applications.

Stem cells are famous for their ability to turn into a variety of specialized cells, but these first applications for fat-derived cells depend less on this ability to assume identities than their ability to stimulate other cells to grow, regenerate or repair themselves.

A number of researchers have noted that the fat-derived cells ---- which scientists yesterday decided to officially call "adipose stem cells," or ASCs ---- encourage the growth of new blood vessels. In the case of heart disease, the cells thus might be used to help the heart grow new vessels to bypass narrowed or blocked coronary arteries that feed the heart.

March said his lab has produced evidence that the cells can become "like a heart cell," and can even beat like heart cells in cell cultures. What's more important than the cells becoming part of the organ, however, is the apparent ability of the cells to support the organ.

Researchers already have evidence that the fat stem cells can become bone, cartilage or skeletal muscle, noted Patricia Zuk, research director of the Regenerative Bioengineering and Repair Lab at UCLA. But even in clinical applications for bone repair, it may be the stem cells' ability to stimulate new vessel growth that is critical. Bone is a highly vascularized tissue, she said.

Stem cells can be found throughout the body, where they normally are involved in repairing or regenerating damaged cells. Their existence in fat tissue was confirmed only three years ago, however. So consensus panels such as yesterday's are needed to help define terms in the young field of adipose stem cells and to reach agreement on what kind of basic and clinical research would best advance the field.

Though bone repair and treatment of vascular disease were emphasized for clinical studies, research is not limited to those areas, emphasized Dr. J. Peter Rubin, a plastic surgeon in the University of Pittsburgh School of Medicine and president of the International Fat Applied Technology Society.

Rubin, for instance, is most interested in using fat stem cells to rebuild breasts following breast cancer surgery. Earlier this year, Japanese researchers began such a clinical study.

And yesterday, Dr. Damian Garcia Olmo of the University of Madrid reported results of a clinical study using fat stem cells to stimulate healing of holes in the intestinal wall, called fistulas, that are a complication of Crohn's disease.

Olmo treated nine fistulas in four Crohn's patients. The trial was primarily to show that the treatment was safe and, in fact, he found no adverse effects. About three-fourths of the fistulas had closed within eight weeks.

He is planning a larger trial, involving 50 patients, to better demonstrate the effectiveness of the treatment.