THE GUT–BRAIN AXIS IN NEUROLOGICAL DISORDERS: FROM MICROBIAL DYSBIOSIS TO THERAPEUTIC INTERVENTION

Abstract

The gastrointestinal tract, gut bacteria, immune system, endocrine pathways, and central nervous system are all connected by the intricate bidirectional communication network known as the gut–brain axis. There is mounting evidence that dysbiosis—a term used to describe changes in gut microbial composition and function—may have an impact on neurological health through alterations in microbial metabolites, intestinal barrier integrity, immune signaling, blood brain barrier function, and neuroinflammation. The architecture and physiological roles of the gut-brain axis are summarized in this overview, which also looks at the main causes of microbial dysbiosis, such as nutrition, aging, antibiotics, stress, lifestyle, and drug use. With a focus on short-chain fatty acids, tryptophan metabolites, bile acids, immunological mediators, and microbial components like lipopolysaccharide, the molecular pathways connecting gut microbial changes with the brain are examined. The link between gut dysbiosis and clinically significant neurological disorders including multiple sclerosis, Alzheimer's disease, Parkinson's disease, epilepsy, stroke, and neuropsychiatric disorders is extensively analyzed, taking into account the difference between an association and a causative role. In addition, the research considers novel microbiome-based approaches, probiotics, prebiotics, synbiotics, postbiotics, microbial metabolites, fecal microbiota transplantation, and dietary interventions for targeting the gut-brain axis. Finally, the possibility of using multi-omics and precision microbiome medicine is highlighted, together with current challenges and translational limitations. Individualized treatment strategies for the management and prevention of neurological diseases can benefit from an improved understanding of host-microbe interactions.