Gastrointestinal Tract, Microbiota and Multiple Sclerosis (MS) and the Link Between Gut Microbiota and CNS

Multiple sclerosis (MS) is a chronic inflammatory disease characterized by central nervous system (CNS) lesions that can lead to severe neurological defects. Evidence is mounting that immune function is crucial in neuroinflammatory illnesses like MS. Through its impact on systemic immunological reactions, the large microbial population known as the gut microbiota has been linked to both human health and disease. The gut-brain axis (GBA) therefore encompasses neurological, immunological, and hormonal pathways, and microbiota can have a number of effects on the immune system, influencing MS. Recent research revealed a bidirectional relationship between metabolites originating from the gut microbiota, namely short-chain fatty acids (SCFAs). Intestinal epithelial cells are influenced by SCFAs, which also boosts the secretion of -Defensins and regenerating islet-derived III (REGIII) proteins. These proteins reduce intestinal pathogens, induce T-reg differentiation, and modulate immune responses by reducing IL-1 and IL-6 expression and increasing IL-10. Nutrition and psychological stress are two of the most significant elements that can directly and indirectly change the microbiota compositions along with other environmental influencing factors. An important regulator of intestinal physiology in the gut-brain-microbiota axis is butyrate, a well-known SCFA. Intestinal dysbiosis, altered intestinal barrier function, behavioral abnormalities, and activation of the hypothalamic-pituitary-adrenal (HPA) axis are all brought on by exposure. Probiotics, bacterial metabolite supplementation, fecal matter transplantation, defined microbial communities, and dietary intervention are some methods for modifying the composition of the gut microbiota that may be used to affect disease-related immune dysfunction and serve as the foundation for a new class of therapeutics.