New obesity research highlighted at ENDO 2004

06/16/04

Findings show promising new treatments and possible risks associated with condition

New Orleans, LA – New treatment options for the millions of people who suffer from obesity could be just around the corner, according to new research presented this week at ENDO 2004, the 86th Annual Meeting of The Endocrine Society. The meeting, which is the largest annual gathering of endocrinologists in the world, will have a special focus on "Obesity, Endocrinology and the future."

During a press conference on Wednesday, June 16, 2004, leading obesity researchers from around the world will discuss some of the latest obesity research, which shows how different body systems, such as the brain, impact overeating as well as possible new treatments options for obesity. The new findings could help doctors and researchers uncover the causes of obesity and identify new ways to treat the growing epidemic and related health conditions.

"With obesity affecting the health of a growing number of people worldwide, researchers and clinicians are working to understand the causes and identify new treatments for this condition. To highlight the important research that is being conducted in the area of obesity, ENDO 2004 will have a special focus on 'Obesity, Endocrinology and the Future.' Throughout the meeting, presentations and activities will highlight the important contributions that the endocrine community is making towards the fight against obesity," noted Endocrine Society President, E. Chester Ridgway, M.D. The five abstracts highlighted below will be discussed in the June 16 press conference, which will take place at 10:00 a.m. CT in the Ernest Morial Convention Center in New Orleans.

Study proves effectiveness of Rimonabant in treating obesity

Scientists have confirmed that rimonabant, a new class of medications, may be a possible new treatment for obesity. The findings could offer a new option to the 64 percent of Americans who suffer from obesity. Dr. Xavier Pi-Sunyer and colleagues at sites around the United States randomized 287 subjects (both men and women between the ages of 18 and 65 with a body mass index of 29 to 41) to receive five, 10 or 20 mg of rimonabant or a placebo, while on a mild hypocaloric diet.

After 16 weeks, patients who took rimonabant lost an average of two to four times (five to eight pounds) more weight than the patients on the placebo. In addition, waist circumference in the patients taking rimonabant also decreased from more than twice as much as the placebos.

"Our findings demonstrate that rimonabant is a safe and effective treatment for obesity," explained Dr. Pi-Sunyer. "These findings may help provide an option for the growing number of people who suffer from obesity, but do not respond to traditional weight loss options such as diet and exercise. Longer and larger studies are needed to confirm these findings."

Drug combination reduces cravings, causes weight loss in rats

Combining two pre-market drugs, which block cravings for tasty, but unhealthy foods, causes weight loss in rats. While researchers know that two drugs--cannabinoid-1 receptor SR141716A (SR) and opioid antagonist LY255582 (LY)--reduce the intake of rewarding food, the effects of combining these two drugs over time has, until now, been unknown.

Dr. Dana Kevin Sindelar and colleagues at Eli Lilly and Co. evaluated the effects of giving SR alone and in combination with LY on body weight and food intake for 14 days in obese rats. One group received oral SR, a second received SR and LY and a third group served as controls.

The study, led by Joelle Dill, found that rats on the SR/LY combination had a greater decrease in food intake and a greater degree of decrease in body weight. Researchers note that weight loss for both groups was maintained at the end of the study and was entirely due to a decrease in fat mass.

Two other groups were given SR for two weeks but this time LY was added for the first week only or for the second week only. Again, body weight and food intake decreased more with the combination, but increased when LY was removed. Likewise, body weight decreased when the LY was added during the second week.

While several studies had suggested that targeting both the cannabinoid-1 and opioid systems could reduce food intake and body weight after one day of dosing, this is the first data indicating that the combination of both could effectively reduce weight, and especially fat mass, over a longer treatment period.

Obese men at risk for infertility

While researchers already know that obesity is an infertility factor in females, new research shows that obese males may also be at risk for infertility. After hypothesizing that obesity impacts hypothalamic and gonadal function in men, which impacts infertility, Dr. Eric Pauli and doctors at Pennsylvania State University College of Medicine investigated fertility markers, such as reproductive history, inhibin B levels, testosterone and semen analysis, in 87 adult males with a range of BMI levels.

Results showed lower testosterone, free testosterone and follicle stimulating hormone (FSH) levels, which indicates mild hypogonadotropic hypogonadism, in men with a higher BMI. Additionally, men with children had a lower BMI.

"These results indicate that obesity is an infertility factor in men as well as women," notes Dr. Pauli. "Our research provides evidence of another risk associated with obesity. At the same time, it may help to identify a cause of infertility in men."

Lack of gut hormone causes obese people to need more food to feel full

British researchers have discovered that people who are obese do not produce enough of the gut hormone PYY3-6 (PYY), which helps people feel full and helps to limit food intake. The results could help explain why some obese people need to eat more food to feel full.

Dr. Carel le Roux, Dr. Simon Aylwin and researchers at Imperial College and King's College Hospital in London provided a series of different sized meals to 20 obese and 21 lean individuals to find out whether obese people experience a PYY deficiency. The researchers measured the release of PYY for 180 minutes after the meal and asked participants to record how full they felt.

While both groups experienced an increase in PYY levels at each size meal, the obese subjects had a lower level of PYY and recorded lower levels of fullness for every size meal, compared with the lean group.

"We found that obese people needed a meal twice the size to achieve the same blood levels of PYY as the lean group," explains Dr. Aylwin. In a second part of the study, the researchers gave 12 lean volunteers graded doses of PYY to examine how different levels of PYY influence the size of a meal. Following each infusion of PYY, subjects were given a buffet meal with no limitations. Again, as PYY levels increased, the subjects ate less food.

"Reduced PYY levels in obese people following a meal could contribute to a reduced feeling of fullness and a larger-sized next meal," notes Dr. Aylwin. "By finding a way to reverse or overcome this deficiency, we may be able to help patients lose weight and maintain the weight loss."

Food taste causes elevated brain activity in obese people

Tasting food causes elevated activity in brain regions involved in the recognition of taste and in the emotional response to ingestion of food in obese people. The new findings could help doctors understand why some people overeat. While taste plays an important role in overeating, scientists have not known whether a person's experience of taste is related to the development of obesity.

Dr. Angelo Del Parigi and Antonio Tataranni at the National Institutes of Health and their colleagues at Good Samaritan Medical Center in Phoenix, Arizona, took pictures of the brains of 21 obese and 20 lean, hungry subjects, both before and after tasting a liquid meal (Ensure plus) following a 36 hour fast. The researchers found significantly elevated activity in the brain regions that are activated in response to the sensory and emotional aspects of food ingestion in the obese subjects.

"Abnormally high activity in the insular cortex region of the brain, which responds to the sensory experience of food, may put people at an increased risk for developing obesity," explains Dr. Del Parigi. "Continued research in this area could help us understand why some people consistently overeat and are susceptible to gaining weight." It is unknown whether the brains of obese people are especially sensitive to food stimuli or if other aspects of being obese change the way the brain responds to any stimulus, note the researchers.

Source: Eurekalert & others

Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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