Bile acids, once considered mere digestive detergents, have emerged as multifaceted signaling molecules with systemic influence extending far beyond the gastrointestinal tract. Recent discoveries reveal their capacity to modulate immune responses, cross the blood–brain barrier, and interact with central nervous system (CNS) cells through their receptors. Neuroinflammation, a key driver of neurodegenerative and neuroimmune disorders, is increasingly linked to bile acid signaling pathways that regulate glial activation, cytokine production, and neuronal survival. This review compiles the current evidence connecting bile acids to CNS inflammation, highlighting mechanistic insights, disease-specific alterations, and the gut–microbiome-bile acid-brain axis. It also explores the therapeutic potential of bile acid derivatives and receptor modulators, as well as their emerging role as biomarkers in conditions such as Alzheimer’s disease, multiple sclerosis, and hepatic encephalopathy. Despite promising advances, critical gaps remain, including the need for bile receptor mapping in human CNS cells, standardized CNS bile acid profiling, and longitudinal metabolomic studies. Bridging these gaps may unlock new strategies for targeting neuroinflammation through bile acid-immune crosstalk.

Inflammatory bowel disease (IBD) is increasingly recognized as a systemic inflammatory disorder associated with elevated long-term risk of ischemic stroke, even among younger individuals without traditional vascular risk factors. Although chronic inflammation, endothelial dysfunction, and hypercoagulability partially explain this association, the biological mechanisms linking intestinal inflammation to cerebral vascular injury remain incompletely defined. Extracellular vesicles (EVs), membrane-bound particles released by epithelial, immune cells and platelets, have emerged as potent mediators of intercellular communication in inflammatory states. In IBD, circulating EVs are enriched with pro-inflammatory cytokines, microRNAs, adhesion molecules, tissue factors, which are capable of promoting endothelial activation, blood–brain barrier disruption, immune-thrombosis and neuroinflammation. This review summarizes epidemiologic, vascular, and EV biology literature to propose a mechanistic framework in which EV-mediated signaling integrates intestinal inflammation with cerebrovascular vulnerability along the gut–vascular–brain axis. While direct causal evidence remains limited, converging mechanistic data supports biological plausibility and defines priorities for future experimental and translational investigation.