Gut Microbiota and Central Nervous System Condemned to Understand Each Other: Their Role in Multiple Sclerosis

The possible relationship between microbiota and inflammatory processes has been known since the 1990’s. However, it was at the beginning of the 21st century that the role played by commensal bacteria (normal microflora, indigenous microbiota) of the gastrointestinal tract in immunomodulating phenomena began to be examined, and, therefore, its effects on the pathogenesis of chronic inflammation, such as ulcerative colitis, rheumatoid arthritis, crohn disease, arteriosclerosis, colon cancer, metabolic diseases and others. Thus, the data show how gut microbiota modulates the production of proinflammatory cytokines such as TNF-α. However, it can be said that it has been in the last five years when studies made have evidenced a possible relationship between the central nervous system (CNS) and gut tract microbiota, or, similarly, the possible intervention of gut microbiota in neuroinflammatory and neurogenerative processes such as depresion, autism, cognitive disorders (dementia), etc. and possibly, multiple sclerosis [1,2].