A New Way to Effectively Suppress the ‘Hunger Hormone’?

Considering that more than two-thirds of U.S. adults are either overweight or obese, understanding the cause of obesity and finding treatments is crucial. It is known that obesity occurs when a person consumes more calories from food than he or she burns. Our bodies need calories to sustain life and be physically active, but when a person eats more calories than they burn, the balance is tipped toward weight gain and obesity. While some people eat even when they are not hungry and for other, complex reasons, many people eat because they ‘feel’ hungry. This sensation is created by a chemical called ghrelin, which fluctuates throughout the day, responding to all kinds of environmental and emotional factors. For more than a decade, efforts to effectively suppress this hormone have met with very limited success, but researchers at John Hopkins University School of Medicine in Baltimore may have found a way!

Dr. Aravind Arepally, clinical director of Hopkins's Center for Bioengineering Innovation and Design, and colleagues used 10 healthy pigs for their study. They chose to work with pigs because their anatomy and circulatory system is very similar to humans. After an overnight fast, the pigs were weighed and blood samples were taken to determine their baseline ghrelin levels. Using X-ray for guidance, the researchers inserted a thin tube through a large blood vessel near the pigs’ groins and into the gastric arteries that supply blood to the area of the stomach that produces ghrelin. There they administered one-time injections of sodium morrhuate, a chemical that destroys the tissue, into five pigs and harmless saline into the others.

After treatment, the pigs who received the chemical stopped gaining weight, while the pigs given saline continued to fatten. Blood samples taken for one month after the treatment showed their levels of ghrelin were suppressed up to 60 percent from baseline. “With gastric artery chemical embolization, called GACE, there's no major surgery. In our study in pigs, this procedure produced an effect similar to bariatric surgery by suppressing ghrelin levels and subsequently lowering appetite,” Dr. Arepally said in a statement.

If a similar procedure could be done safely in humans, it could complement or substitute for bariatric surgery, the researchers said. Bariatric surgery involves removal, reconstruction or bypass of part of the stomach and sometimes small intestine so that people eat less and so their bodies have less time to digest food. While bariatric surgery is effective in suppressing appetite and leading to significant weight less, it carries substantial risks and complications. Regardless, about 205,000 people in the United States had bariatric surgery last year. “This procedure (GACE) leaves the stomach’s anatomy intact, and just targets the part that produces the hormone,” said Dr. Arepally. “Obesity is the biggest bio-medical problem in the country, and a minimally invasive alternative would make an enormous difference in choices and outcome for obese people.”

Dr. Arepally said the chemical and the GACE procedure are already approved by the Food and Drug Administration, and he is currently talking to pharmaceutical companies to design a better way to try this approach in people. “One of the things I want to do—I want to put this chemical in a better format,” he said. “We just injected this chemical into the blood vessels.”

The study was published in the September 16 issue of Radiology.