The role of microbial succinate in the pathophysiology of inflammatory bowel disease: mechanisms and therapeutic potential.

Inflammatory bowel disease (IBD) is a chronic immune-mediated condition linked to gut microbiota dysbiosis and altered production of bacterial metabolites, including succinate, which is also a key intermediate in human mitochondrial energy metabolism in human cells. Succinate levels in the gut are influenced by microbial community dynamics and cross-feeding interactions, highlighting its dual metabolic and ecological importance. Extracellular succinate acts as a key signaling metabolite linking microbial metabolism to host physiology, with transient rises supporting metabolic regulation but chronic elevations contributing to metabolic disorders and disease progression. Succinate signals through its cognate receptor SUCNR1, which mediates adaptive metabolic responses under normal conditions but drives inflammation and fibrosis when dysregulated. IBD patients display a dysbiotic gut microbiota characterized by an increased prevalence of succinate-producing bacteria, contributing to elevated succinate levels in the gut and circulation. This imbalance drives inflammation, worsens IBD severity, and contributes to complications like Clostridioides difficile infection and fibrosis. Emerging evidence highlights the potential of intestinal and systemic succinate levels as indicators of microbial dysbiosis, with a bidirectional relationship between microbial composition and succinate metabolism. Understanding the factors influencing succinate levels and their interaction with dysbiosis shows promise in the development of therapeutic strategies to restore microbial balance. Approaches such as dietary fiber enrichment, prebiotics, and probiotics to enhance succinate-consuming bacteria, combined with targeted modulation of succinate pathways (e.g. SDH inhibitors, SUCNR1 antagonists), hold promise for mitigating inflammation and improving gut health in IBD.