Objective: Sleeve gastrectomy (SG) is widely used in treating obesity because of significant weight loss and anti-diabetic effects, but there are still cases of long-term weight loss failure. Our aim was to explore the weight loss mechanism following SG in mice to learn how initial improvements in glucose metabolism are reversed in the long term.
Methods: C57/BL6 mice were divided into two groups, one undergoing SG and the other sham surgery. Body weight, gastric volume, blood glucose level, and the expression of sodium-glucose cotransporter 1 (SGLT1) were assessed at 2 weeks, 1 month, and 2 months after surgery.
Results: The SG mice had reduced food intake and lost weight during the 30 days after surgery. However, food intake and weight recovered gradually and even surpassed the sham group after 30 days. SGLT1 expression decreased within 1 month after SG and then increased at 2 months. Although initial SGLT1 expression levels in the stomach were much lower than at intestinal sites, levels increased following surgery and then decreased. The gastric volume decreased after SG, but was significantly increased at 2 months, exceeding the gastric volume in the sham mice.
Conclusions: The metabolic benefits of SG are achieved through reduced gastrointestinal glucose absorption as evidenced by decreased expression of SGLT1 without bypassing the proximal intestine as in other forms of bariatric surgery. In addition, SGLT1 expression in the stomach may play a greater role in post-surgical metabolic effects, but further studies are needed.
Keywords: Glucose absorption; Obesity; Residual gastric volume; SGLT1; Sleeve gastrectomy; Type 2 diabetes; Weight loss.