The Role of Bile After Roux-en-Y Gastric Bypass in Promoting Weight Loss and Improving Glycaemic Control

Abstract

Gastric bypass leads to the remission of type 2 diabetes independently of weight loss. Our hypothesis is that changes in bile flow due to the altered anatomy may partly explain the metabolic outcomes of the operation. We prospectively studied 12 patients undergoing gastric bypass and six patients undergoing gastric banding over a 6-wk period. Plasma fibroblast growth factor (FGF)19, stimulated by bile acid absorption in the terminal ileum, and plasma bile acids were measured. In canine and rodent models, we investigated changes in the gut hormone response after altered bile flow. FGF19 and total plasma bile acids levels increased after gastric bypass compared with no change after gastric banding. In the canine model, both food and bile, on their own, stimulated satiety gut hormone responses. However, when combined, the response was doubled. In rats, drainage of endogenous bile into the terminal ileum was associated with an enhanced satiety gut hormone response, reduced food intake, and lower body weight. In conclusion, after gastric bypass, bile flow is altered, leading to increased plasma bile acids, FGF19, incretin. and satiety gut hormone concentrations. Elucidating the mechanism of action of gastric bypass surgery may lead to novel treatments for type 2 diabetes.

Bile acid profiles over 5 years after gastric bypass and duodenal switch: results from a randomized clinical trial

“…Most short-term studies (< 2 months after surgery) report unchanged or decreased levels of total BAs [26][27][28], while most studies reporting data from several months and years after surgery report increased concentrations [18,20,[29][30][31][32]. Our findings are in accordance with the existent literature, and extend the current knowledge by showing that the BA levels apparently continue to increase up to 5 years after RYGB.…”

Nonalcoholic fatty liver disease and bariatric surgery: a comprehensive review

“…It is clear that while weight loss plays an important role in controlling metabolic abnormalities, this effect appears to be more significant over the long term. [158][159][160] Furthermore, there is evidence that excess weight is not the main pathophysiological feature relating to NAFLD. 158 The causes of early improvement of MetS after bariatric surgery are complex and relate to changes on the entero-insular axis mediated by gastrointestinal hormones called incretins.…”

Obesity diabetes and the role of bile acids in metabolism

“…The increase in bile acids strongly correlates with the improvement in glucose and lipid metabolism [28,29] . Interestingly, catheter-mediated bile diversion to the mid distal jejunum in rats induces weight loss, decreases adiposity, improves glucose tolerance, and increases circulating bile acids [30] .…”