The role of the gut microbiota in the development of rheumatic diseases: a focus on fibromyalgia.

Fibromyalgia (FM) is a chronic widespread pain syndrome affecting 2%-4% of the population whose pathophysiology remains incompletely understood. Growing evidence implicates gut microbiota dysbiosis as a contributing factor, acting through immune, neuroendocrine, and metabolic pathways that may reinforce central sensitization. Consistent findings of reduced microbial diversity and altered metabolite profiles-including short-chain fatty acids, bile acids, and tryptophan derivatives-suggest mechanistic links between the gut and FM symptoms. Microbiota-targeted interventions such as probiotics, dietary modification, and fecal microbiota transplantation have shown preliminary benefits, though evidence remains limited by small sample sizes and methodological heterogeneity. This review synthesizes current knowledge on the role of the gut microbiota in FM within the broader context of rheumatic diseases and discusses future research directions.