Effects of Lactulose on Gut Microbiota and Metabolism in Diabetic Constipated Patients

Constipation is the most common gastrointestinal manifestation in diabetic patients. Emerging evidence suggests that gut microbiota dysbiosis may contribute to the pathogenesis of diabetes, highlighting the need to investigate its role in diabetic constipation, though current research remains limited. Current management of diabetic constipation primarily relies on bulk-forming and osmotic laxatives. Additionally, microbiome-modulating agents (e.g., probiotics, prebiotics, and synbiotics) may serve as adjunctive therapies by regulating gut microbiota and enhancing intestinal motility. Lactulose, a well-tolerated osmotic laxative with prebiotic effects, is widely recommended in clinical guidelines. It promotes short-chain fatty acid production, increases fecal volume, and accelerates colonic transit, thereby alleviating constipation. However, its specific impact on gut microbiota composition and metabolic pathways in diabetic constipation remains unclear. This study aims to explore changes in fecal microbiota and metabolomic profiles in diabetic patients with chronic constipation following treatment with lactulose alone or in combination with Bacillus subtilis-Enterococcus faecium probiotics, providing mechanistic insights into prebiotic therapy for this condition.