EXPLORING THE ROLE OF GUT MICROBIOTA IN PATIENTS WITH MULTIPLE SCLEROSIS IN UKRAINE: A CROSS-SECTIONAL STUDY

Introduction. Multiple sclerosis (MS) is an inflammatory disorder characterized by demyelination in the central nervous system (CNS), linked to both genetic predispositions and environmental influences. Gut microbiota can be considered as an environmental factor that plays a role in MS disease. Aim. The study aims to assess enterotype and microbiota composition in multiple sclerosis patients and a control group in the Ukrainian population, as well as to identify factors influencing their formation and role in disease pathogenesis. Materials and methods. A total of 33 subjects, from which 28 diagnosed with multiple sclerosis (MS) and 5 healthy volunteers participated in this single-center cross-sectional study. Data were collected from stool samples obtained from participants, medical records and neurological exam during 2025. Microbiome analysis was performed via 16S rRNA gene sequencing on the Illumina MiSeq platform. Results. The MS and control cohorts had comparable demographic characteristics. The median age was 33 (IQR: 31-37). In this study we investigated the impact of gut microbiota on adults with multiple sclerosis in Ukraine and found that enterotype has potential moderate-strong association with MS, and were significantly related to treatment status. The association among enterotype distribution and treatment status was with large effect (Cramér’s V = 0.41), indicating relationship between microbiome changes and DMT therapy. In our study MS patients also had an increased level of the phylum Proteobacteria (d=-0,36) and decreased levels for Bacteroidetes (d=0.27) and Firmicutes (d=0.44) compared to healthy controls. Kruskal-Wallis H test showed that Firmicutes (H = 12.262, p = 0.016) and Proteobacteria (H = 10.18, p = 0.037) differ significantly between control group, group without treatment and preventive therapy groups. Other phyla do not show statistically significant differences. Conclusions. This study demonstrates that gut microbiota composition in MS patients differs from that of healthy controls, with enterotype distribution potentially influenced by disease-modifying therapies. Increased levels of proinflammatory phylum have been identified in the MS cohort, so further studies on genus and species level is needed.