Gut microbiota: A possible role in the pathogenesis of multiple sclerosis

Abstract

Multiple sclerosis (MS) is an autoimmune disease affecting the central nervous system, in which both genetic and environmental factors are involved. Prevalence of MS is increasing remarkably in Asian countries including Japan, indicating a role of environmental factors related to westernization of lifestyle. Recent studies in immunology have demonstrated the dependency of pathogenic or regulatory lymphocytes on the gut microbiota component. Based on the epidemiological data in human and mouse immunology studies, we have been hypothesizing that alterations in the gut microbiota may underlie the pathogenesis of MS at least in Japan. Very recently, analysis of the bacterial 16S ribosomal RNA (rRNA) gene by using a high-throughput culture-independent pyrosequencing method provided evidence of a moderate dysbiosis in the structure of gut microbiota in Japanese patients with MS. Furthermore, we have identified 21 species that showed significant differences in relative abundance in MS as compared with healthy subjects, 2 increased and 19 reduced. The taxa reduced in MS comprised primarily of clostridial species belonging to Clostridia clusters XIVa and IV. Correcting the dysbiosis and altered gut microbiota might deserve consideration as a potential strategy for the prevention and treatment of MS.