Gut Microbiota and Diabetic Complications: Potential Mechanisms, Microbial Signatures, and Clinical Implications

Type 2 diabetes mellitus is a systemic metabolic disorder with an extensive spectrum of complications, which still persist despite improvements in glycemic control. Emerging evidence suggests that gut dysbiosis may be an underpinning factor in the pathogenesis of both microvascular and macrovascular complications associated with diabetes. This narrative review explores the relationship between gut microbiota and the development of diabetes complications, including nephropathy, retinopathy, neuropathy, cardiovascular, cerebrovascular, peripheral vascular, and reproductive system disorders. First, existing evidence regarding the nature of shared and organ-specific microbial patterns is summarized. Next, key mechanistic pathways of inflammation and metabolism underlying tissue damage induced by dysbiosis are illustrated. Lastly, the role of gut microbiota and inflammaging as modifiers of these processes is described. Emerging clinical and translational implications are finally discussed, underscoring the promises of microbiota-based diagnostics as well as therapeutics that could serve as add-on approaches to the management of diabetic complications, alongside the application of artificial intelligence-based approaches to microbiome data analysis which may enhance biomarker discovery and risk stratification. Overall, although most evidence remains associative, increasing data support that gut microbiota dysbiosis may represent a potential disease modifier in the development of various diabetic complications. Further longitudinal and mechanistic studies are needed to clarify causality and to evaluate the clinical utility of microbiome-targeted interventions, including AI-assisted predictive models, in preventing or mitigating diabetic complications.