Making Obese Mice Slim, Without Diet or Exercise

June 4 -- WEDNESDAY, June 3 (HealthDay News) -- Researchers have come up with two new ways to control weight and blood sugar levels in obese mice -- without diet or exercise.

And although putting the techniques to use in people is a long way off, they hope the research will help in the development of drugs that could be used to treat obesity or type 2 diabetes.

The findings appear in two studies in the June issue of Cell Metabolism.

In one of the studies, researchers inserted a molecular shunt into the liver cells of 94 mice.

Despite chowing down on high-fat foods that mimicked a human fast-food diet, the mice with the genetically engineered shunts stayed skinny, compared with mice without the shunts.

The shunt, which contained an enzyme normally found in bacteria and plants but not in mammals, acted as an "artificial engine" that enabled liver cells to burn more fat.

Instead of accumulating in the blood or being stored by the body, the fat was metabolized, converted to carbon dioxide and exhaled.

"Exercise is always a good way to burn fat, but we found you can increase the metabolic channels for burning fat even without exercising more," said study author James Liao, a professor of chemical and biomolecular engineering at the University of California, Los Angeles.

Dr. Stuart Weiss, an endocrinologist at New York University Langone Medical Center, said the concept of boosting the liver's ability to burn energy without stepping up physical activity is intriguing.

"The idea that we can use this shunt pathway to manipulate fatty acid metabolism in the liver is very exciting as a basic science question," Weiss said.

Still, genetic engineering has not yet been used to successfully treat people, so any anti-obesity treatments using molecular shunts are years away, Liao said.

In the other study, researchers were able to restore blood glucose levels in obese, severely diabetic mice to normal -- again without changing their diets or activity levels.