While symptoms of the second group improved moderately, the third group demonstrated dramatic improvements in both body weight and diabetes. The fourth group exhibited nearly 100 percent recovery in all areas.
To bolster these findings, Shi and colleagues then took a group of mice whose ability to produce mast cells was genetically impaired. Despite three months of a diet rich in sugar and fat, these mice neither became obese nor developed diabetes.
"The best thing about these drugs is that we know it's safe for people," says Shi. "The remaining question now is: Will this also work for people?"
Shi now intends to test both cromolyn and ketotifen fumarate on obese and diabetic non-human primates.
Beyond friendly fire
In findings independent of Shi, researchers at Harvard Medical School and Joslin Diabetes Center discovered that a class of immune system cells called regulatory T cells, or Tregs, were abundant in the abdominal fat tissue of normal-weight humans and mice, but were virtually absent in the same tissue from obese and diabetic humans and mice.
Their numbers were inversely correlated with the numbers of a class of inflammatory immune cells, macrophages, in a sense creating parallel universes of fat. While obese and diabetic fat tissue was full of inflammatory macrophages and nearly absent of Tregs, normal-weight fat tissue was the diametric opposite.
"For immunologists this is very important, because Tregs had always been thought to control other T cells and that's it," says Markus Feuerer, a postdoctoral researcher in the lab of HMS professors of pathology Diane Mathis and Christophe Benoist. "But this is an entirely new concept." Mathis and Benoist collaborated on the study with Steven Shoelson, HMS professor of medicine at the Joslin Diabetes Center.
"I come at this studying the
|Contact: David Cameron|
Harvard Medical School