Fat-burning pill closer to reality, Harvard researchers say

Harvard University researchers say they're one step closer to creating a pill that may someday replace the treadmill, thanks to a breakthrough that can change the way energy-storing white fat cells behave.

The laboratory work enables scientists to more easily manipulate white fat cells, the bad kind that stores energy for later use and contributes to obesity and diabetes, according to the report in Nature Cell Biology. The scientists screened about 1,000 compounds and found two that make the white fat cells act more like their brown cousins, which burn excess energy rather than store it.

"What we wanted to do is take the white fat no one wants, especially post-holidays, and turn it into the fat everyone wants, the brown fat," said senior author Chad Cowan, a faculty member at the Harvard Stem Cell Institute. The results suggest "you could someday come up with a small molecule that might be a pill that would replace a treadmill in terms of its ability to burn fat or burn calories," he said in a telephone interview.

The researchers worked with stem cells that would normally turn into white fat cells. Exposing the cells to drugs, including Pfizer Inc.'s rheumatoid arthritis medicine Xeljanz, made them behave more like brown cells that burn fat to regulate body temperature. The researchers next will test the medicine in animals to see if it produces the same metabolic changes seen in the laboratory tests, Cowan said.

A cursory examination of Xeljanz research didn't show if the drug had an effect on the metabolism or weight of rheumatoid arthritis patients, Cowan said. Pfizer officials didn't have an immediate comment on the findings. The researchers are hoping to find a way to deliver the medicine directly to fat cells rather than infuse it widely in the body, where it depresses the immune system as a way to treat rheumatoid arthritis, Cowan said.

While the original investigation was conducted with the support of Roche Holding AG, the company has stopped working in the area, Cowan said. He is talking with several pharmaceutical companies to interest them in the work.

Exercise has numerous benefits beyond burning fat and lowering weight, including controlling cholesterol and blood pressure, boosting mood and energy levels, and enhancing sleep and mental function.

A medicine "would never replace the other benefits of exercise, so in no way would I tell people to stop exercising," Cowan said. "But this does give us great hope that with further research we could come to the realization that you could have a therapy for both obesity and diabetes."