1942-P: Vertical Sleeve Gastrectomy Confers Metabolic Improvements by Reducing Intestinal Bile Acids and Lipid Absorption in Mice

Vertical sleeve gastrectomy (VSG) is one of the most effective and durable therapies for morbid obesity and its related complications. Although bile acids (BAs) have been implicated as downstream mediators of VSG, the mechanisms through which changes in BA content and signaling contribute to the metabolic effects of VSG remain poorly understood. Therefore, in this study, we aim to systematically evaluate the roles of FXR in VSG and determine the underlying mechanism by which bile acids mediate the beneficial effects of VSG. Our data demonstrated that both intestine- and liver-specific farnesoid X receptor (Fxr) knockout mice retained VSG effects and VSG did not appear to increase FXR activation in the liver or intestine, indicating that hepatic or intestinal FXR is dispensable for the metabolic improvement of VSG. We further found that VSG altered gut microbiota composition and reduced intestinal BA levels in mice, resulting in lower intestinal fat absorption and concomitant metabolic improvements similar to those observed in Fxr null mice. We then confirmed these findings in sterol 27-hydroxylase knockout (Cyp27a1^-/-) mice, which exhibited low intestinal BAs and fat absorption, did not experience metabolic improvements after VSG. Our findings reveal that reductions in intestinal BAs and lipid absorption may underlie the metabolic benefits of VSG.