Changes in Gut Microbiome Taxonomic Composition and Еheir Relationship to Biosynthetic and Metabolic Pathways of B Vitamins in Children with Multiple Sclerosis

Multiple sclerosis (MS) is a chronic inflammatory autoimmunedisease characterized by progressive demyelination, leading to thedeath of neurons in the central nervous system. Although the disease typicallymanifests itself in people aged 20–40 years, recent years have witnesseda rising incidence of early-onset MS. We assume that this may bedue to the peculiarities of the gut microbiota taxonomic compositionand its ability to produce B vitamins. This work was aimed to revealchanges in the gut microbiome composition in the onset of multiplesclerosis in children and adults, and to assess the potential ofthe gut microbiome to synthesise and metabolise B vitamins. Thestudy included 15 children (aged 9–17 years) and 15 adults withMS manifested in childhood, as well as 14 adults over 35 years of agewith MS duration less than one year. The gut microbiome compositionwas identified by sequencing the 16S rRNA gene on the Illumina platformwith universal primers for the 16S rRNA V3–V4 variable region. ThePICRUSt algorithm using the KEGG reference genome database was appliedto predict the presence of B vitamin metabolic pathways in the gutmicrobiome. In the onset of MS, children exhibited specific microbiomechanges different from those in adults, which included a decreasein alpha diversity, as well as a reduction in the dominant phylaand an increase in p_Verrucomicrobiota and p_Mycoplasmatota, accompanied bya decrease in the number of bacterial genes involved in metabolic andbiosynthetic pathways of vitamins B1, B2, B3, B5 and B12. Thesechanges may relate to the early manifestation of MS symptoms inchildren. Our findings accentuate the importance of further investigatingthe impact of the gut microbiome and its metabolic potential onMS development and progression, especially in childhood, and maycontribute to the development of more effective methods to treatand prevent demyelinating diseases.