Characteristics of the Gut Microbiota in Multiple Sclerosis Patients: An Analytical Observational Study

Abstract

Background:

Multiple sclerosis (MS) is a chronic disease of the central nervous system characterized by autoimmune inflammation, demyelination, and axonal damage. MS has been linked to neuroinflammatory effects originating in the gut. Recently, research has focused on the gut microbiota composition and the differences in the abundance of specific taxa in patients with MS. We aim to determine the distribution of bacterial composition in the intestinal microbiota of patients with MS and to compare them with healthy controls.

Methods:

A total of 27 individuals were selected for the study, 18 of whom were in the MS group and nine in the healthy control group. Participants were surveyed to obtain some demographic and clinical information, body mass index, vitamin D use, and weekly consumption levels of prebiotics–probiotics, carbohydrates, fast-food, and some other foods. Stool samples were also collected.16S rRNA gene sequencing was executed on the samples using the Illumina MiSeq platform. Bioinformatics (alpha and beta diversity indices) and statistical analyses (analysis of similarity, principal coordinate analysis, permutational multivariate analysis of variance, linear discriminant analysis effect size, Ward′s hierarchical clustering method, etc.) were applied to compare the gut microbiome composition of the groups.

Results:

In the bioinformatics analysis process, all samples were analyzed for 391 taxa. However, due to the complete absence of some taxa or the very low relative abundance of some taxa (n_{excluded−taxa} = 249), only 142 taxa were included in the analysis. No significant differences were provided between the groups for microbiota diversity indices (p > 0.05). However, we found that 22 taxa were discriminatory in the gut microbiota compositions of groups. Actinomyces from the phylum Actinobacteria, unclassified some genera (Barnesiellaceae_, Barnesiellaceae_g_, and Desulfovibrionaceae_g) from the families Barnesiellaceae, Desulfovibrionaceae, a genus classified as other (Veillonellaceae_g_other) from the family Veillonellaceae showed higher levels in the MS patients compared with the healthy controls (p < 0.05). The control group showed significant increases in relative abundance of Blautia, Peptococcus from the phylum Firmicutes, Pseudomonas from the phylum Proteobacteria, unclassified genus (Streptophyta_g_) from the order Streptophyta, unclassified genera (Pseudomonadaceae_g_, Lachnospiraceae_g_) from the families Pseudomonadaceae and Lachnospiraceae (p < 0.05).

Conclusion:

In our study, it was thought that the increase in the taxa Actinomycetaceae, Barnesiellaceae, Desulfovibrionaceae, and Veillonellaceae, which have been proven to be associated with inflammatory processes in the intestinal microbiota, and the decrease or loss of the taxa Blautia, Opitutae, and Lachnospiraceae, which are important parts of the eubiotic microbiota, may be effective in MS disease by causing inflammatory processes. We believe that our findings will make a crucial contribution to establishing a picture of the gut microbiota composition in MS patients.