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New Study Discovers How the Metabolism Can Contribute to Obesity

metabolismobesityThose who have trouble keeping weight off may have genetics to blame, according to a new study from the Massachusetts Institute of Technology and Harvard University.

In 2007, researchers discovered that a gene called FTO can play a role in obesity. The new experiments have found that this gene is also tied to appetite and propensity for exercise, too.

But MIT and Harvard researchers worked together and found that this gene could actually be reversed, thanks to some “genetic tinkering” that the researchers did on mice and human cells.

Manolis Kellis, a professor of computer science and a member of MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) and of the Broad Institute, said that the study opens new doors into how obesity is treated by medical professionals.

“Obesity has traditionally been seen as the result of an imbalance between the amount of food we eat and how much we exercise,” said Kellis, a senior author of the study. “But this view ignores the contribution of genetics to each individual’s metabolism.”

First author Melina Claussnitzer, a visiting professor at CSAIL and instructor in medicine at Beth Israel Deaconess Medical Center and Harvard Medical School, said that the study has given new insight into how brain activity can affect obesity.

“Many studies attempted to link the FTO region with brain circuits that control appetite or propensity to exercise,” said Claussnitzer. “Our results indicate that the obesity-associated region acts primarily in adipocyte progenitor cells in a brain-independent way.”

The MIT and Harvard study used the adipose samples of healthy Europeans carrying either the risk version of the gene, which could cause that obesity-associated region of the brain to switch on, and the non-risk version of the gene.

The risk version affected two distant genes, IRX3 and IRX5, both of which can contribute to obesity.

This means that even those who receive treatments like laser liposuction or tummy tucks may have trouble maintaining their weight loss if they don’t possess those energy-burning beige fat cells. Other research has shown that liposuction patients, for instance, are three times as likely to gain weight again without proper diet and four times as likely if they don’t exercise, but these newly discovered genes and different fat cells could also be responsible.

That could open the door for a new drug to help obese Americans lose weight. Worldwide, obesity affects more than 500 million people, leads to heart disease and diabetes, and costs the U.S. public about $200 billion in health and preventative care each year.

This could even be great news for residents of Detroit and the state of Michigan, which ranks as the 11th heaviest state in the country. The adult obesity rate in Michigan is 31.5% overall, with the same number for men and a 30.7% rate for women.

The study, which was published in the New England Journal of Medicine, has been praised by others in the field.

“It’s a big deal,” said Dr. Clifford Rosen, a scientist at Maine Medical Center Research Institute and an associate editor of the New England Journal of Medicine. “A lot of people think the obesity epidemic is all about eating too much… [but] you now have a pathway for drugs that can make those fat cells work differently.”

Although many drugs on the market target obesity, they are generally for short-term weight loss only and aren’t designed to change the metabolism.



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