Professor Fredrik Backhed, in collaboration with Randy Seeley and coworkers from the University of Cincinnati in the US, has shown that the positive effects of bariatric surgery are likely caused by the surgery-induced increase in bile acids. The study focuses on a specific receptor called FXR, which is involved in bile acid signaling.
Fredrik Backhed said their study shows that signaling through FXR is essential for the beneficial effects of the surgery to be achieved. This is a major breakthrough in understanding how bariatric surgery affects metabolism and in the development of new treatment strategies.
In this study, mice with or without the FXR gene underwent an operation termed vertical sleeve gastrectomy (VSG) in which approximately 80 percent of the stomach was removed. The surgical procedure is the same as that performed in humans.
The researchers observed that the operation promoted weight loss and improved glucose metabolism in mice with FXR while the operation had no effect in mice that lacked FXR.
This study also showed that VSG resulted in changes in the gut microbiota, a potentially important finding given that Fredrik Backhed's research group has previously demonstrated that the intestinal bacterial flora is altered in obesity and diabetes.
The study has been published online in the journal Nature.