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International MS Microbiome Study Links Gut Bacteria to MS Susceptibility, Severity and Treatment in Novel Study

September 16, 2022

A new study published by the International MS Microbiome Study Consortium links gut bacteria to MS susceptibility, severity and treatment. This team is using novel technologies to investigate this pathway to MS cures in large numbers of people with MS from different locations around the world.
  • Each of us has millions of “commensal” bacteria and other microorganisms living within our intestines (collectively known as the microbiome). Most of these are harmless and some appear to play a critical role in our normal physiology, such as in establishing and maintaining immune balance by the molecules they release.
  • A Collaborative MS Center award from the National MS Society to lead author Sergio Baranzini, PhD (University of California, San Francisco) fostered a U.S. collaboration of talented individuals from a wide range of disciplines to come together to answer fundamental questions about the role that gut bacteria may play in MS. This led to the formation of a global International MS Microbiome Study (iMSMS) Consortium. The team is funded by the Valhalla Foundation and receives support from the Society, among others.
  • The iMSMS team recruited participants with MS and study controls without MS from the same households as the participants. This enables them to tease out genetic and environmental effects.
  • For this publication, they report on gut microbiome differences between 576 people with MS and 576 household controls in the United States, the United Kingdom, Spain and Argentina. The team collected data from stool and blood samples, clinical measures of disease activity, and questionnaires on diet. They analyzed the samples using advanced DNA sequencing techniques.
  • The results identify dozens of new bacteria species associated with MS and confirm other species previously identified. The team found differences suggesting a role for gut microbiome in susceptibility to MS. They also confirmed that individuals’ geographic locations contribute heavily to the gut microbiome, as do MS type and severity. Age, sex, and body mass also impact composition of the microbiome, and to a lesser degree, diet.
  • Although further study is needed to examine how each form of bacteria contribute to MS and how they might be manipulated to reverse symptoms, some hints emerged. People with MS who were not being treated with disease-modifying therapies showed reduced amounts of 7 species of bacteria including ones with beneficial anti-inflammatory properties. Some beneficial modifications to the gut microbiome were observed in response to treatment with disease-modifying therapies. Several species of bacteria were linked to disease severity.
  • The authors comment, “The origin and biological relevance of these associations remain to be elucidated. Nevertheless, our study supports the possibility that microbial manipulation and dietary intervention could be used as preventive and therapeutic strategies in MS.”
  • In further studies, the team will follow participants for more than two years to see how gut bacteria change in response to treatment, lifestyle changes, and MS progression.
Learn more…
Read more about this study on the UCSF website
Learn more about the iMSMS Consortium and participate in this research
Gut microbiome of multiple sclerosis patients and paired household healthy controls reveal associations with disease risk and course,” by the iMSMS Consortium is published in Cell 2022;185:19(P3467-3486).

About Multiple Sclerosis

Multiple sclerosis is an unpredictable, often disabling disease of the central nervous system. Symptoms range from numbness and tingling to blindness and paralysis, and there is currently no cure for MS. The progress, severity and specific symptoms of MS in any one person cannot yet be predicted, but advances in research and treatment are leading to better understanding and moving us closer to a world free of MS. An estimated 1 million people live with MS in the United States. Most people with MS are diagnosed between the ages of 20 and 50, and it affects women three times more than men.


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