February 2021

The exact mechanisms underlying the metabolic effects of gastric bypass or bariatric surgery remain unclear.  At the University of Iowa Carver College of Medicine, Mohamad Mokadem, MD, Assistant Professor of Internal Medicine and member of FOEDRC, and his research team have developed an animal model of bariatric surgery, which they are using to understand the underlying mechanisms by which this treatment not only prevents obesity but also reverses diabetes. Mokadem’s lab studied obese animals that underwent bariatric surgery (i.e. weight loss surgery) in order to understand the body’s physiologic response to such a treatment. Understanding these responses could lead to the development of similar therapies that are less invasive.  They found that one type of bariatric surgery, namely the Roux-en-Y Gastric bypass, induces its weight loss and other metabolic benefits by altering the activity of a specific nerve (the splanchnic)  that connects the gut to the brain to cause direct burning of the fat within the abdomen. This fat burning increases energy expenditure and is specific for this  model of bariatric surgery.   The new findings in their study identified a receptor within the intestine (the Endocannabinoid-receptor-1) that seems to be responsible for activating this “splanchnic” nerve signal to cause the metabolic benefits of this surgical procedure.  The main implication of these findings on patient care is the future possibility of manipulating a specific receptor or its downstream effectors or the splanchnic nerve itself, to mimic the long-lasting effects of bariatric surgery.  The more we understand details of how bariatric surgery works the more we will understand the underlying changes that are leading to the obesity epidemic. In addition, this research may lead to less invasive options to manage obesity and to reverse diabetes.