Hormone May Help Reduce Cholesterol
An experimental hormone that has shown promise in boosting the immune system of patients with AIDS and blood diseases also has an unexpected ability to lower cholesterol in the bloodstream, according to UCLA Medical Center researchers.
The finding, being reported in Thursday’s issue of the Journal of the American Medical Assn., may stimulate research to develop new cholesterol-lowering drugs, according to Dr. Stephen D. Nimer, an assistant professor of medicine at UCLA and principal author of the study.
“Our report is the first to demonstrate an effect of this class of hormone on cholesterol metabolism,” Nimer said.
The researcher cautioned that the hormone, known as GM-CSF, is unlikely to replace current anti-cholesterol drugs, except perhaps in rare instances, because of its high cost, potential side effects and its inability to be given in pill form.
Reasons Unknown
Although the researchers don’t know why GM-CSF lowers cholesterol, they found “very marked” decreases in cholesterol levels in eight patients who received the hormone, according to Nimer. The average decrease was 37%, comparable to the amount of decrease found with the most powerful cholesterol-lowering drugs currently available.
GM-CSF, or granulocyte-macrophage colony-stimulating factor, is a naturally occurring human hormone that has been produced in large quantities through genetic engineering. Because it stimulates diseased bone marrow to make large numbers of infection-fighting white blood cells, it has been tested as a potential therapy for patients with cancer, AIDS and a variety of blood diseases.
The new UCLA study involved eight patients with aplastic anemia, a condition in which the bone marrow can no longer make sufficient numbers of blood cells. To determine the proper dose of the hormone, the patients were given continuous intravenous infusions of GM-CSF for about four weeks. The patients who were able to tolerate the hormone had marked increases in their white blood cell counts.
Seven of the eight patients had substantial reductions in their cholesterol levels, in particular the LDL cholesterol, which has been associated with clogging of the arteries, Nimer said. These were independent of changes in their white blood cell counts. According to Nimer, the seven started with cholesterol values as high as 270 milligrams per deciliter. All reached cholesterol values below 170. The patient with little change in cholesterol level had a very low value to begin with. (Medical experts consider a cholesterol level below 200 to be desirable for adults, 200 to 239 to be borderline and more than 240 to be high.)
The reductions in cholesterol were seen within days of starting the patients on GM-CSF, but did not persist after the hormone therapy was stopped, according to the report. Side effects of the GM-CSF included headaches, muscle pains and fatigue. Moreover, the hormone cannot be given as a pill because it would be inactivated in the stomach.
