Functional potential of gut microbiome in paediatric MS

A study using metagenomic sequencing found differences in the functional potential of the gut microbiome of patients with paediatric-onset MS compared with controls at various metabolic pathways [1]. Exposure to disease-modifying therapy (DMT) was associated with enrichment of pathways involved in promoting central nervous system remyelination.

A Canadian group examined the gut microbiome functional diversity and potential by metagenomic analysis of stool samples from 20 patients ≤21 years old (mean age 16.1 years) with paediatric-onset MS and from 20 matched controls. Exposure to antibiotics or corticosteroids 30 days prior to sampling was not allowed. MS patients were either DMT-naïve (n=8) or used interferon-beta or glatiramer acetate (n=12).

There were no significant differences in functional alpha-diversity by disease or DMT status. However, differential analysis of metabolic pathways revealed that MS patients exhibited higher Archaea-related methanogenesis, flavin biosynthesis (producing vitamin B and flavin cofactors), viral activity, metabolism of heavy metals, and degradation of L-glutamate (which produces the short-chain fatty-acid propionate). These differences were not significant for the DMT-naïve versus DMT-exposed MS patients. Homolactic fermentation (lactate production, associated with anti-inflammatory effects) and bacterial carbohydrate degradation were lower in MS patients than in controls. In patients using a DMT, an enrichment of pathways involved in promoting CNS remyelination was observed versus DMT-naïve MS patients. For example, choline biosynthesis was enriched in DMT-exposed patients (log-fold change 21; 95% CI 12–29; P<0.0001).

1. Mirza A, et al. Functional survey of the pediatric multiple sclerosis microbiome. MSVirtual 2020, Abstract PS10.03.