Gut microbiota composition associated with disability worsening

A new study found a high prevalence of dysbiotic Bacteroides 2 enterotype at baseline and after 3 months in patients with relapsing-remitting multiple sclerosis (RRMS), with additional worsening of the Expanded Disability Status Scale (EDSS) Plus score after 4–5 years. These results underscores the possible involvement of gut microbiota in MS and its potential as a prognostic biomarker.

Several neurological diseases, such as MS, Parkinson's, and Alzheimer's disease, are associated with alterations in the microbiota, called dysbiosis. In the experimental autoimmune encephalomyelitis (EAE) model of MS, modulation of the gut microbiome has been shown to alter the disease [1]. Numerous studies in humans, mainly cross-sectional, have shown subtle differences in specific bacteria, but results are very diverse. By comparison, the number of longitudinal studies of gut microbiota are scarce and most failed to shed light on the possible relation between gut microbiota and long-term disability worsening. To this end, a longitudinal study was conducted by Dr Ayla Pauwels (Vrije Universiteit Brussel, Belgium) and colleagues, including 111 MS patients; 86 with RRMS and 25 with primary progressive MS (PPMS) [2].

Only 27 patients received treatment at baseline; they were all RRMS patients and were all treated with interferon-beta. Studied were the diversity, enterotypes, and specific gut microbial taxa variations between subgroups. There exist 4 clusters/community types in the gut microbiota: Bacteroides 1 (B1), Bacteroides 2 (B2), Prevotella (P), and Ruminococcus (R). “Every single person has one predominant enterotype, which can change over time,” Dr Pauwels explained.

After a mean follow-up of 4.4 years, 39/95 patients had worsened EDSS-Plus score. Baseline enterotype was found to be related to EDDS-Plus worsening. Of patients who had a worsened EDSS score at the last timepoint, a much higher percentage had a B2 enterotype at baseline and after 3 months versus patients who did not worsen (close to 50% vs about 30%, respectively). A B1 enterotype was much more prevalent in the group that did not worsen (just over 50%). These differences were largely driven by the RRMS group, in which they were even more prominent.

Gut microbiota could thus possibly serve as a prognostic biomarker in patients with RRMS and are a target for personalised microbiome therapies.

1. Berer K, et al. Proc Natl Acad Sci USA. 2017;114(40):10719–24.
2. Pauwels A, et al. Gut microbiota composition is associated with disability worsening in MS. Late Breaking News 1, EAN 2022, 25–28 April, Vienna, Austria.

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Posted on 22 August, 202223 April, 2024