iMSMS Findings Offer Insight Into Gut Microbiome Involvement in MS

Recent findings from the global collaborative International Multiple Sclerosis Microbiome study (iMSMS) identified modest but statistically significant multiple sclerosis (MS) linked changes in gut microbiota composition and function in patients with the disease. This was according to study findings presented at the 8^th Joint American Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) and European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) MSVirtual2020 event, held September 11-13, 2020.

To date, the iMSMS is the largest reported study of the gut microbiome in patients with MS. The goal of this study was to identify microbes, genes, and pathways involved in MS pathogenesis, as well as to examine the effect of treatment on microbiome changes. This analysis of the iMSMS included a total of 576 patients with MS and household healthy control pairs who were enrolled from 7 centers in the United States, Europe, and South America. Study researchers collected stool samples and evaluated these with both 16S and shallow whole metagenome shotgun sequencing. Patterns of variation of the gut microbiome were analyzed using univariate and multivariate linear regression analyses.

According to the researchers, there was a significant difference between patients with MS and healthy controls in terms of beta diversity. The microbiomes of untreated patients with MS were significantly enriched for multiple Akkermansia species, including the mucin-degrading bacterium Akkermansia muciniphila. However, there was no difference between the treated case and control groups regarding this enrichment.

In cases with MS, the most significantly enriched bacteria included Ruminococcus torques and Eisenbergiella tayi. In the untreated patients with MS, Faecalibacterium prausnitzii, a main butyrate producer, was significantly reduced. Additionally, untreated patients with MS exhibited slightly increased functional pathways of L-tryptophan biosynthesis and L-threonine biosynthesis. Patients with MS who did receive treatment had increased 5-aminoimidazole ribonucleotide biosynthesis I.

The investigators from this study concluded that “strain-level genomic variation and microbiome-derived molecules need to be further explored for understanding microbial adaptation and pathogenicity” in patients with MS.

Reference

Singh S, Mendoza M, Baumann R, et al. Exploring the gut microbiome in multiple sclerosis via the international MS Microbiome Study (iMSMS). Presented at: 8^th Joint American Committee for Treatment and Research in Multiple Sclerosis and European Committee for Treatment and Research in Multiple Sclerosis MSVirtual2020 event; September 11-13, 2020. Abstract P0671.