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Vol. LXII, No. 18
September 3, 2010
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Can Correct Weight, Metabolism
Researchers Explore Bariatric Surgery for Adults, Teens

  Dr. Lee Kaplan  
  Dr. Lee Kaplan  

As American waistlines continue to expand, doctors are widening their tool set accordingly to help their patients address the problem and lose the weight.

With the complications that being overweight or obese can bring—type 2 diabetes, hypertension, heart disease, arthritis and sleep apnea, to name a few—it’s no wonder patients are often willing to try almost anything to shed the extra pounds. The available options include diet, exercise, medication and, in some cases, bariatric surgery, especially when excess weight is causing health complications that make it difficult for the patient to lose weight in other ways.

Surgical intervention, often described as stomach stapling or gastric banding, can be a critically valuable therapy for patients whose severe or medically complicated obesity leaves them few other options. Bariatric surgery was the subject of a pair of recent lectures in the NIH obesity research task force’s seminar series on the uses and effects of the procedure in adolescents and adults.

Dr. Thomas Inge of Cincinnati Children’s Hospital Medical Center not only studies use of this surgery for teens, but also directs the Center for Bariatric Research and Innovation. He is currently principal investigator for a large multicenter bariatric study funded by NIH.

The slides he presented in Lipsett Amphitheater offered a grave picture of what the medical community is up against as our sedentary lifestyles, poor eating habits and technological conveniences fill our lives with more calories than we could ever use. And it’s not just adults who are guilty of eating chips on the couch, a soda in one hand and a remote control in the other.

Blowflies, which are known to show up at the first sign of waste and can cross-contaminate surfaces, were rampant during Lubbert’s visit.  

Dr. Thomas Inge of Cincinnati Children’s Hospital Medical Center

 

“Pediatric obesity is becoming an increasing problem,” Inge said. “The complications this causes and the quality of life limitations can persist into adulthood.”

While the idea of using bariatric surgery in patients who are not yet of age may sound controversial, the procedure has produced such dramatic results that researchers now recognize new groups of patients in whom the benefits likely outweigh the risks. Once someone undergoes a typical bariatric procedure, weight loss is usually substantial and sustained, which is a big positive in the long run.

“This is significant because many preteens are developing huge BMIs,” Inge said.

BMI, or body mass index, is the calculation of height as it relates to weight. The higher the BMI, the greater a person’s risk of developing weight-related health complications. With bariatric surgery, a person’s BMI drops significantly and generally stays that way.

“It’s a manipulation of the digestive tract that hopefully will allow the weight-loss effect to persist over time,” Inge said.

Of course any surgery, especially on a youngster, is not without risks, which is why Inge stresses that it only be used in special circumstances after an assessment of co-morbidities (complications compromising a patient’s health) and informed consent. Even then, the weight loss comes with some risks attached. Recent data from a randomized trial of adjustable gastric banding in Australian teens showed that 24 percent required additional procedures after the original surgery. This high rate of early reoperations has not been reported with other types of surgery in teenagers.

Still, Inge says that early intervention in an obese patient may be preferable, because it could correct co-morbidity factors sooner, giving the patient a longer, healthier life.

For Dr. Lee Kaplan, another NIH researcher who is director of Massachusetts General Hospital’s Weight Center and who works extensively on obesity and gastrointestinal physiology, examining what bariatric surgery can do for patients involves more than just weight.

By manually correcting the body’s food intake system with surgery, he says, the feedback loop that regulates energy balance and metabolism is dramatically altered.

“The body does defend its weight,” Kaplan said, by regulating the amount of stored fat. This occurs even in the presence of obesity, which is why long-term weight loss from diets is so difficult to achieve.

By changing the body’s “set point” through bariatric surgery, the signaling between body and brain about energy intake and expenditure is rewired. The body recognizes that it doesn’t need as much food and begins correcting the imbalance of being overweight by burning off excess fat, thus aiding and maintaining weight loss. It’s as if the surgery hits a “reset” button on the body’s ability to regulate weight naturally.

“It goes well beyond the weight,” Kaplan said. “In our animal models, we have seen that surgery also prolongs lifespan and improves diabetes and metabolic diseases more generally. The changes in metabolic function are related to the surgery, but not necessarily to the weight loss. Surgery creates a sense that the body is overweight, which the body then corrects to drive itself to a new, lower set point.”

While this intervention would seem to be a magic bullet for many who struggle with weight, Kaplan said the procedure is a “fairly blunt tool,” and its effectiveness must be balanced against its invasiveness, risk and cost. Because surgery is so effective, however, we can study how it works and use those physiological mechanisms to design less costly and invasive means of mimicking its effects, he said. One of the lessons learned has been the value of combination therapies for obesity.

“Combination therapies targeted to individual patients will be most effective” in tackling obesity, he said. “I see a bright future where we get away from the ‘one size fits all’ thinking.” NIHRecord Icon


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