News article

Activating Immune System Could Treat Obesity, Diabetes

Posted:  Wednesday, June 11, 2014

Spiraling obesity rates have resulted in alarming rates of diabetes, heart disease and cancer. Scientists are however hopeful that in the next two years a new jab could be available to tackle obesity and in turn slash the associated health risks.

Obesity is a worldwide epidemic that is causing alarming rates of diabetes and cardiovascular disease, but currently there is a lack of effective drug treatments. Two unrelated studies published by Cell Press on 5th June in the journal Cell reveal an important role for immune pathways in activating good types body fat, called brown and beige fat, which burn stored calories, reduce weight, and improve metabolic health. The findings could pave the way for much-needed treatments for obesity and related metabolic diseases.

"The idea that metabolic health can be improved by activation of immune cells in fat is pretty amazing," says senior study author Bruce Spiegelman of the Dana-Farber Cancer Institute and Harvard Medical School. "This research reveals an exciting new class of potential treatments that could one day be used for obesity-related disorders."

Human infants have large amounts of heat-generating brown fat to protect them from extreme cold, and scientists recently discovered that adult humans retain small amounts of brown fat consisting mainly of a subtype known as beige fat.

Cold exposure or exercise can activate brown or beige fat, which burn stored calories and protect mammals from hypothermia, obesity, and metabolic problems.

Despite their therapeutic potential for treating these conditions, relatively little was known about the molecular pathways that trigger the formation of these good types of fat.

The new study focused on a protein that stimulates the secretion of a hormone which is released into the bloodstream and produced in muscle tissue after exercise and in fat tissue after cold exposure in mice. By converting energy-storing white fat to calorie-burning brown or beige fat, the hormone increases energy expenditure and improves metabolic health in obese, diabetic mice.

This hormone could potentially be suitable as a new therapy for obesity and diabetes. The new research focused on a protein found to stimulate the secretion of the hormone irisin. Prof. Spiegelman said “Harnessing irisin could help scientists develop better therapies for any illness that can be controlled by exercise”.

The breakthrough marks an important first step in understanding the biological mechanisms that translate physical exercise into beneficial changes throughout the body, both in healthy people and in preventing or treating disease.

Prof. Spiegelman said: 'There has been a feeling in the field that exercise ‘talks to’ various tissues in the body. But the question has been, how?'

The report said the irisin hormone has direct and 'powerful effects' on adipose or fatty tissue - deposits of white fat that store excess calories, which contribute to obesity.

When irisin levels rise during exercise - or when injected directly into mice - it switches on genes that convert white fat into brown fat. In the wake of findings by Prof. Spiegelman and others, there has been a surge of interest in the therapeutic possibilities of increasing brown fat in adults.