Introduction and Objective: Type 2 diabetes (T2D), obesity, and inflammatory bowel disease (IBD) are increasingly common inflammatory disorders. Additionally, comorbid obesity and T2D are linked to more severe IBD. Glucagon-like peptide-1 receptor agonists (GLP-1RAs), such as Semaglutide (Sema), are thought to promote weight loss and improve glycemic control through peripheral and central nervous system (CNS) pathways, while also exerting anti-inflammatory effects. This study examined whether Sema reduces IBD severity in diet-induced obese (DIO) mice and whether this involves a central mechanism of action. Methods: Adult male C57BL/6 mice consumed a high-fat diet for 12-14 wks to induce DIO, then underwent subcutaneous (subQ) implantation of an osmotic minipump containing either Sema or vehicle (veh). In separate studies, Sema was delivered either subQ (40 μg/kg bw), or infused directly into the brain via an intracerebroventricular (ICV) cannula at a much lower dose (4 μg/kg bw; a dose with no peripheral effect). After 14d, 2% dextran sodium sulfate (DSS) was given in drinking water for 10d to induce colitis. Results: Peripheral and central Sema both caused weight loss before DSS, with a greater effect from peripheral dosing (peripheral Sema: -18.44%, p0.0001 vs veh. Central Sema: -8.62%, p0.0001 vs veh, p0.0001 peripheral vs central). Sema reduced both clinical and histopathologic DSS colitis severity given centrally (18.3% and 17.6%, respectively; p0.0001 for each) or SubQ (35.9% and 12.9%, respectively; p0.0001 for each). Systemic Sema also lowered colonic proinflammatory cytokine expression, an effect not seen with ICV Sema. Conclusion: We report that DSS colitis is ameliorated by Sema administration, whether given centrally or systemically. Additional mechanistic studies are needed, but we conclude that activation of GLP1 receptors in the brain is sufficient to improve outcomes in a mouse model of IBD. Disclosure B. Desai: None. K. Francis: None. C. Bryan: None. J.N. Connolly: None. T. Karunagaran: None. S.A. Mathan: None. K. Sharma: None. C.A. Watts: None. P. Choi: None. K.H. Kadlec: None. B.N. Phan: None. M.C. Pacheco: Research Support; Current; Taisho Pharmaceutical Holdings Co., Ltd. G. Morton: None. M.W. Schwartz: Consultant; Current; Eli Lilly and Company. J. Scarlett: None. Funding National Institutes of Health (2T32DK007247-46)
DESAI et al. (Fri,) studied this question.