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Research on fat cells may offer answers to diabetics (6/25/97)

Robert I. Gregerman, MD, believes that basic research is the foundation upon which medical miracles are built. Dr. Gregerman is a professor of medicine at The University of Texas Health Science Center at San Antonio and associate director for research at the Geriatric Research, Education and Clinical Center (GRECC) at South Texas Veterans Health Care System, Audie L. Murphy Division. He is also a pioneer whose early research was instrumental in developing a new class of medications, now commonly used to treat hypertension and heart failure.

Dr. Gregerman is currently studying a substance that transforms baby fat cells into mature cells. His research may tell us why obese people become diabetic, and may also be applied in a more practical way by transplant surgeons when they want to use precursor cells to form fat deposits.

For instance, Jaime R. Garza, MD, DDS, chief of the division of plastic surgery at the Health Science Center, is looking forward to the future when the results of Dr. Gregerman's research may make it possible to implant precursor cells into a woman's body after a mastectomy. These cells could grow and possibly help fill out the space to eventually appear much like the patient's original breast. Dr. Garza and other plastic surgeons can now reshape excessive abdominal tissue and form a breast for a woman who has had a mastectomy.

"The surgeon removes a pad of fat and skin from the patient's abdominal area and attaches this, with its blood supply, to the vessels under the arm. This tissue is then sewn to the chest area," Dr. Garza explained. "Once the patient has recovered she can go home whole, and feel good about herself."

"There is a long history of attempting to use fat for soft tissue reconstruction, even from the seventies." Dr. Gregerman said. "A decade ago plastic surgeons were saying what needed to be done was to transplant immature cells to the surgical site and get these cells to grow and mature, so this isn't a new idea. Its just that not much has been done with it."

Dr. Gregerman explained that mature fat cells secrete a substance that causes a change when interacting with an immature cell or with itself, or when it enters the body's circulatory system.

"We decided that anything that came from fat cells was worthy of research so we decided to isolate and characterize this substance," Dr. Gregerman continued. "We hope to begin studies to determine if this secretion has anything to do with the body's resistance to insulin action, such as occurs in diabetes. Most diabetics are obese, and some physicians and scientists are looking for what there is in fat that leads to the development of diabetes.

"Artificial chemicals can cause immature (precursor) fat cells to change --to grow up--and chemical agents turn on the production of the genes in these precursor cells," the endocrinologist said. "This is what actually happens when immature cells grow and mature. We are making this transformation happen by using the natural substance prepared in our laboratory."

Dr. Gregerman states that his interests have always been in basic research. It was his early research on an enzyme called renin that was eventually used by other scientists to develop a class of commonly used hypertensive drugs called ACE (angiotensin-converting enzyme) inhibitors.

"As frequently happens, our research wasn't for this specific purpose, but since ACE inhibitors are currently among the most important drugs in the field of cardiology, it is nice that this happened the way it did," Dr. Gregerman said, smiling.

There are already a number of antidiabetic drugs on the market, one of which promotes the transition of precursor fat cells to mature cells. A number of researchers are interested in this link between precursor and mature fat cells and high blood sugar in diabetes. Dr. Gregerman's research, however, may help in learning why obese people become diabetic. Perhaps a preventive medication or drug that could cure diabetes might develop from current studies.

True to form, this pioneer who calls himself a basic researcher, is taking a "wait and see" attitude.

"How our discoveries will be used in the future remains to be seen,'' Dr. Gregerman said. "Sometimes basic research leads to something that is practical, sometimes not. If it turns out that it is of practical use, that's terrific, but my interests are in basic research. That is the way medical progress is made."

A magna cum laude graduate of Harvard University, Dr. Gregerman was a professor at Johns Hopkins University School of Medicine for almost two decades before joining the Health Science Center faculty. He was also chief of the endocrinology section and an investigator for the National Institute on Aging at the National Institutes of Health in Baltimore, Md.

Contact: Jan Elkins (210) 567-2570