Gut Microbiota Seen to Differ in People with Relapsing MS, Especially Those with Active Disease

Fecal samples from a group of people with relapsing-remitting multiple sclerosis (RRMS) showed evidence of a different gut microbiota than that found in healthy controls, and may be a non-genetic reason for the altered immune system responses seen in MS patients. The study, “Multiple sclerosis patients have a distinct gut microbiota compared to healthy controls,” was published in the journal Scientific Reports.

Both genetic and environmental factors are known to play a role in MS. Recent studies suggest that gut microbiota, the complex community of microorganisms that live in the digestive tract, are a key environmental factor for MS.

Researchers here investigated whether the gut microbiome differs in patients with relapsing MS, particularly, when compared to age- and gender-matched people serving as controls. The scientists analyzed microbial DNA extracted from fecal samples from 31 RRMS patients and 36 healthy people using DNA sequencing.

They observed that RRMS patients carry a distinct fecal microbiome when compared to the controls: specifically, they detected an increased abundance of microbes belonging to the Pseudomonas, Mycoplana, Haemophilus, Blautia, and Dorea genera in MS patients, while controls showed higher levels of Parabacteroides, Adlercreutzia and Prevotella genera.

Previous studies have linked some of the most frequent type of bacteria now identified in MS patients to inflammatory diseases, such as inflammatory bowel disease (IBD). However, researchers noted that further studies with larger patient cohorts are needed to define the role of the gut microbiota abundant in MS patients.

Notably, in this study, RRMS patients with active disease showed a reduced richness in microbial species when compared to patients in remission and to controls. This suggests that less diverse microbial communities may lead to disease exacerbation.

Overall, results support the hypothesis that MS patients indeed have a gut microbial imbalance (dysbiosis), and  Additionally, suggest that gut microbiota is a potential environmental factor triggering disease progression in genetically susceptible individuals.

Larger studies, with detailed and controlled time for sample collection and analysis, are required to more fully investigate the functional changes in the intestinal microbiota and understand how gut microbiota may exacerbate abnormal immune responses, leading to inflammatory diseases like RRMS.