Metabolic Surgery and the Improvement of Type 2 Diabetes: Clinical, Physiological and Molecular Mechanisms

Background and purpose: The prevalence of type 2 diabetes mellitus has increased along with the global epidemic of obesity. One of the most important advances in metabolic surgery is its impact on type 2 diabetes. In this review, the effect of metabolic surgeries, and their physiological and molecular effects have been investigated on weight loss, improvement of diabetes, and metabolic disorders. Materials and methods: Metabolic surgeries have been introduced as an effective treatment modality for type 2 diabetes. This review discusses various types of metabolic surgeries along with their benefits and drawbacks. It also explores the different physiological and molecular mechanisms that contribute to the improvement or remission of diabetes. Results: In general, anatomical, physiological, and molecular changes in the gastrointestinal tract, independent of weight loss, can effectively improve blood glucose levels and regulate insulin secretion over a long period. The most important effects of metabolic surgery include enhanced insulin sensitivity, improved functionality and enhanced quantity of β cells in the pancreas, increased insulin release by affecting incretin hormones, alterations in the configuration and circulation of bile acids and intestinal microbiota, and improvement in intestinal glucose metabolism. Conclusion: Considering the significant effects of metabolic surgery on improving type 2 diabetes independent of weight loss, it would be valuable to explore the different mechanisms that contribute to glucose reduction after surgery.