Roux-en-Y gastric bypass surgery restored normal regulation of the appetite hormone ghrelin, an analysis of the STAMPEDE trial found.
In addition, bypass patients lost more belly fat and had improved insulin secretion compared with patients who had sleeve gastrectomy, even though their total weight loss was the same, according to Sangeeta R. Kashyap, MD, of the Cleveland Clinic, and colleagues.
The finding that bypass surgery patients had greater suppression of acylated ghrelin two years after surgery and had better metabolic outcomes, including pancreatic beta-cell function, suggests that ghrelin suppression may play a key role in improved glucose control, they wrote in the International Journal of Obesity, published online Nov. 22.
"Our data highlight plasma acylated ghrelin as a potential modifying factor in Roux-en-Y gastric bypass (RYGB)-induced diabetes remission," the authors wrote.
Several theories have been proposed to explain the positive effects of bariatric surgery on diabetes prior to weight loss.
The hindgut hypothesis suggests that diabetes control results from the more rapid delivery of nutrients to the distal small intestine, thereby enhancing the release of hormones such as glucagon-like peptide-1 (GLP-1).
The foregut hypothesis, in contrast, suggests that exclusion of the proximal small intestine reduces or suppresses the secretion of anti-incretin hormones, leading to improvement of blood glucose control as a consequence.