Monash scientists target brown fat brain processes for ‘skinny pill’

SCIENTISTS are working on a “skinny pill” after tracing how the brain converts fat into weight-loss tissue.

Diet pic from Thinkstock to go with Lauren Dor column on women and weight-loss issues. Oct 5, 2013.

MELBOURNE scientists are working to create a “skinny pill” after zeroing in on the brain processes that help convert fat into special weight-loss tissue.

The tissue, known as “brown fat”, burns energy rather than storing it. It keeps babies and small mammals warm and helps ward off diabetes, obesity and other disorders. People were thought to lose their brown fat stores by the age of three, until scanning breakthroughs in 2009 revealed that it still exists in adults.

Since then scientists have found that the more brown fat people have, the leaner they tend to be. Researchers have shown that brown fat stores rise when people live in cold environments, and studies on mice suggest that exercise can convert ordinary white fat into “beige” tissue that behaves like brown fat.

Brian Oldfield, from Monash University’s School of Biomedical Sciences, said brown fat needed to be “activated” by nerve cells before it could burn calories. “It’s pointless having all the brown fat in the world unless it’s recruited by the nervous system,” he said.

“We’re trying to identify a part of the brain that will help us selectively activate brown fat. If we can learn how brown fat is triggered by the brain to burn calories, it will provide us with an ideal weight-loss solution.”

The goal is to identify a “neurotransmitter” which performs this role without sparking other unwanted processes, such as increasing blood pressure. Professor Oldfield said the body had hundreds of different types of neurotransmitter proteins.

The team is yet to identify a “candidate” protein, or even a shortlist, but experiments on rats have given an indication where to look.

Using a technique unique to their group, the researchers track artificially glowing virus cells as they make their way through the rats’ nervous systems, before and after brown fat stores have been stimulated by cold or exercise. “We’ve started to look at the rewiring of the nervous system that occurs after the browning of the white fat,” Professor Oldfield said.

He was reluctant to predict if and when the team might find its candidate. But if it does, the tremendous global interest in brown fat means the team will be able to “move very quickly” in developing a drug to trigger it.

Professor Oldfield said medical interventions were needed to overcome the obesity epidemic. Diet and exercise were the ideal solutions, but the last 30 years had shown they had limited impact at a population level. And while turning off the heat might activate the body’s natural obesity defences, people were “too used to being warm”.