Using fruit flies, U.S. researchers have uncovered a protein called TOR which is linked with heart disease.
TOR, a nutrient-sensing protein, regulates molecular circuits involved in growth, metabolism and lifespan, and normally keeps a damper on an enzyme that breaks down fats.

Manipulating TOR protects the hearts of obese flies from damage caused by high-fat diets, researchers at Sanford-Burnham Medical Research Institute said in the study appearing in the Nov. issue of the journal Cell Metabolism.

In the study, the researchers fed flies with a high-fat diet of coconut oil so as to make them obese and exhibit many of the same secondary symptoms as obese humans, including heart dysfunction.

Then, to determine how TOR regulates the effects of fat on the heart, the researchers generated flies that lowered this protein's activity. By inhibiting TOR (or boosting the fat-digesting enzyme), the researchers reduced fat accumulation in the heart and improved the cardiac health of otherwise obese flies.

The heart-protective results were the same whether TOR was blocked in the whole fly, just in fat tissue or just in heart cells, the researchers said.

"We noticed previously that reducing TOR had a large number of beneficial effects on aging," explained Dr. Sean Oldham, co-senior author of the study. "We next wanted to look at TOR activity in obesity-related heart disease, but we didn't have a good system. In this study, we establish the fruit fly as a model for obesity caused by a high-fat diet."

The fruit fly model is ideal for studying the heart because most of the basic molecular mechanisms controlling its development are surprisingly similar to those in vertebrates -- even somewhat interchangeable. What's more, it's relatively easy to delete individual genes in the fly, allowing researchers to specifically map out each one's role in heart development and function, according to the researchers.

"These results open the possibility that we can intervene with the effects of obesity by targeting TOR and other proteins it regulates -- either directly in fat or in a specific organ like the heart," said Rolf Bodmer, Ph.D, co-senior author of the study and professor and director of the Development and Aging Program.

VietNamNet/Xinhuanet