Navigation Links
Born to Be Obese?

New research suggests brains of heavy individuals may be wired differently

TUESDAY, Feb. 5 (HealthDay News) -- The brain circuitry that controls appetite might be wired differently in some people, and that could predispose them to obesity, California researchers suggest.

The study was conducted in rats, not humans, and yet it could ultimately lead to novel obesity treatments, said Philip Smith, director of the Office of Obesity Research at the National Institute of Diabetes and Digestive and Kidney Diseases.

"It is not just about drugs that modify short-term appetite," he said, "there may be drugs that stimulate development of the appropriate neural pathways. So, it is an exciting, but very early, time in this field."

The study was published in the February issue of Cell Metabolism.

Sebastien Bouret, an assistant professor of neuroscience at the University of Southern California, and his colleagues examined neural circuits emanating from the appetite, hunger and body-weight control center of the brain -- the so-called arcuate nucleus of the hypothalamus (ARH) -- in a series of rats bred to be either prone to, or resistant to, obesity.

The team found fewer neural connections projecting from the ARH in obesity-prone animals than in their leaner counterparts. Surprisingly, Bouret said, this deficiency developed very early in life, before the animals became obese, and appeared to extend into adulthood.

"Somehow, these animals are programmed to become obese," Bouret said. "The obesity is hard-wired into the brain."

When the researchers then looked at why the brains of obese rats differed from their normal-weight counterparts, they found that the neurons from obesity-prone animals were less responsive to leptin, a hormone that controls the development of these circuits, and which also signals the body's energy status and controls metabolic rate.

"This paper presumes to say, these animals must be leptin-resistant, and that is why the pathways are not developing," said Smith.

But that doesn't mean they are doomed to a life of severe obesity, said Dr. Barbara Kahn, chief of the Division of Endocrinology, Diabetes and Metabolism at Beth Israel Deaconess Medical Center, in Boston. How they live their lives also matters.

"It is important not to 'blame' the obese person or imply that he/she is responsible for being obese," Kahn noted. "Having said that, reasonable, healthy caloric restriction and a safe and sustainable program of physical activity can help limit weight gain and often bring about some degree of weight loss. In addition, healthy eating and regular exercise can reduce the complications of obesity such as type 2 diabetes and cardiovascular disease."

At the same time, she added, not everyone can wear a size 4.

"There is a certain aspect of genetics that sets somebody in a certain range of possible body weights, and then how that person lives his or her life will determine whether they are at the bottom or top of the range," she explained.

Human obesity has both genetic and environmental roots. The rats used in this study, like most humans, developed obesity when fed a high-energy diet. On a normal diet, they were heavier than normal rats, but not yet obese.

"This is quite an exciting paper," said Smith, "because it links more closely to human behavior than most rodent models we have seen."

The findings also suggest a possible therapeutic approach to combating human obesity. If drugs could be designed to influence the formation of neural circuits during development and targeted to at-risk pregnancies, Smith said, "there is a good likelihood we could have successful interventions that improve the health of the mother, and which have a major impact on disease risk for the infant, during pregnancy."

A related study from Boston University researchers in the same journal found that bulking up muscle mass can lead to a general metabolic improvement in obese individuals. "Interventions designed to increase skeletal muscle mass in at-risk human populations may prove to be critical weapons in the fight against obesity and obesity-related comorbidities, including diabetes, heart disease, stroke, hypertension and cancer," an accompanying editorial stated.

More information

For more on obesity, visit the National Institute of Diabetes and Digestive and Kidney Diseases.

SOURCES: Sebastien G. Bouret, Ph.D., assistant professor, neuroscience, University of Southern California, Los Angeles; Philip Smith, Ph.D., co-director, Office of Obesity Research, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Md.; Barbara Kahn, M.D., chief, Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, and George R. Minot Professor of Medicine, Harvard Medical School, both in Boston; February 2008, Cell Metabolism

Copyright©2008 ScoutNews,LLC.
All rights reserved  

Post Your Comments:
Related Image:
Born to Be Obese?
(Date:11/28/2015)... ... November 28, 2015 , ... Trying to relax on a couch can actually ... conceived of this design due to personal experience with a bad back," he said. ... and convenience, as well as increases support. It also makes it easier to eat, ...
(Date:11/28/2015)... Viejo, CA (PRWEB) , ... November 28, 2015 , ... ... new fully customizable media panels to choose from, the possibilities are endless. Users have ... and more. With the ProPanel: Pulse masking effects, users are sure to get heads ...
(Date:11/27/2015)... CA (PRWEB) , ... November 27, 2015 , ... According ... at the recent 2015 American Dental Association meeting in Washington D.C. revolved around the ... protect a patient’s overall health. The talk stressed the link between periodontal disease (more ...
(Date:11/27/2015)... ... November 27, 2015 , ... According to an article published November ... they are handling security in light of the recent terrorist attacks in Paris, other ... to stop an attack from reaching U.S. soil. Especially around special events that may ...
(Date:11/27/2015)... ... November 27, 2015 , ... A team of Swiss doctors ... treat it. Surviving Mesothelioma has just posted the findings on the website. Click ... analyzed the cases of 136 mesothelioma patients who were treated with chemotherapy followed by ...
Breaking Medicine News(10 mins):
(Date:11/26/2015)... Research and Markets ( ) has announced ... Outlook to 2019 - Rise in Cardiac Disorders and Growing ... to their offering. Boston ... scientific and others. --> The market ... Boston scientific and others. ...
(Date:11/26/2015)... , November 26, 2015 ... the addition of the  "2016 Future ... Global Cell Surface Testing Market: Supplier ... to their offering.  --> ... of the  "2016 Future Horizons and ...
(Date:11/26/2015)... , November 26, 2015 ... the addition of the  "2016 Future ... European Therapeutic Drug Monitoring (TDM) Market: ... Intelligence, Emerging Opportunities"  report to their ... has announced the addition of the  ...
Breaking Medicine Technology: