With obesity gaining momentum, scientists are getting closer to understanding how the disease progresses, providing clues for future treatments.
In one study published in the journal Cell Metabolism, researchers examined the hormone leptin and how a resistance to it can develop. Leptin is a key hormone in the cause of obesity.
Lead author Professor Tony Tiganis, of the Monash Obesity and Diabetes Institute and Monash University’s Department of Biochemistry and Molecular Biology, said our bodies produce leptin in response to increasing fat deposits.
“Acting on a part of the brain called the hypothalamus, leptin instructs the body to increase energy expenditure and decrease food intake, and so helps us maintain a healthy body weight,” said Professor Tiganis.
“The body’s response to leptin is diminished in overweight and obese individuals, giving rise to the concept of ‘leptin-resistance’. We’ve discovered more about how ‘leptin-resistance’ develops, providing new directions for research into possible treatments.”
Previous studies have revealed two proteins that inhibit leptin in the brain and Professor Tiganis’ team have discovered a third.
Tests performed on mice revealed this third protein as more abundant with weight-gain, exacerbating leptin-resistance and hastening progression to morbid obesity. The study showed that the three negative regulators of leptin take effect at different stages, shedding light on how obesity progresses.
“Drugs targeting one of the negative regulators are already in clinical trials for Type 2 Diabetes; however, our research shows that in terms of increasing leptin-sensitivity in obesity, targeting only one of these won’t be enough. All three regulators might need to be switched off,” said Professor Tiganis.
When two of the negative regulators were removed from the test mice, weight gain from a high fat diet was largely prevented.
“We now have to determine what happens when all three negative regulators are neutralised. Do we prevent high fat diet-induced obesity?”
Professor Tiganis said the more that is known about obesity, the better-equipped scientists are to develop drugs to support good diet and exercise choices.
“Humans have a deep-seated attraction to overeating and nutrient-rich food, inherited from our hunter-gatherer ancestors. Now that food is more readily available and our lifestyles are less active, our evolutionary drive to overeat is becoming problematic.”
“Simply telling people to eat less and exercise more is not going to be sufficient to reverse the obesity trend. There is a pressing need to develop novel drugs that complement diet and exercise to both prevent and treat this disease,” said Professor Tiganis.
Monash University. “Another clue to how obesity works.” ScienceDaily, 14 Oct. 2011. Web. 18 Oct. 2011.