Dozens of gut bacteria are associated with multiple sclerosis

In recent years, scientists have increasingly made connections between intestinal bacteria and a number of diseases—not just diseases of the gut—including diabetes and arthritis. However the link between gut bacteria and multiple sclerosis (MS) has been unclear, mainly because studies have used small numbers of participants and it has been difficult to exclude the effects of the environment.

International consortium

Now, a consortium of scientists participating in the International Multiple Sclerosis Microbiome Study (iMSMS) have recruited a large number of people living with MS from three continents and selected genetically unrelated controls from the same households. It it the first time this methodology has been used in such a large study.

iMSMS is led by the University of California San Francisco. The Anne Rowling Clinic is one of the recruiting sites and so far nearly 300 pairs of people with MS with a household control have participated in this study from the Clinic, providing valuable data for this global effort.

New findings from the study, which have been published in the scientific journal Cell, describe differences between the gut microbiome profiles of 576 people with MS and an equal number of household controls in the United States, Canada, the United Kingdom, Germany, Spain and Argentina. With their innovative protocol, the team was able to identify dozens of new bacteria species associated with MS and confirm other species that had previously only been associated with the disease. They were surprised by just how much variation there was in the types of bacteria between people with MS and controls.

Drug mechanisms

Using genetic analysis of the bacteria, the researchers are trying to understand the effect of the different bacterial profiles on a person's MS. For example, some of the bacteria the team found to be associated with MS seem to play a role in helping humans process fibre from plants. Other species seem to have an influence on inflammation and the energy production machinery of the cell.

The research can also provide hints about how disease-modifying therapies for MS actually work. It provided evidence that interferon beta-1a, the oldest therapy for MS, might work by increasing the transportation of molecules called short-chain fatty acids from the gut to the blood stream. Short-chain fatty acids are known for their anti-inflammatory properties.

The findings from iMSMS could lead to new therapeutics that involve either manipulating the microbiome or dietary interventions.

This is an example of how big science can only be achieved collaboratively. In the iMSMS, we really brought together the best and the brightest researchers in the microbiome research field and in multiple sclerosis, and they're all pulling towards the same objective.

Opportunity to participate

The iMSMS group will continue to recruit participants until the total number reaches 2000.

We would like to thank everyone who has already participated in this important initiative from the Anne Rowling Clinic. If you would like to get involved, please see our MS Microbiome Study page, or speak to your care team.

Related links

Read the scientific article: "Gut microbiome of multiple sclerosis patients and paired household healthy controls reveal associations with disease risk and course". iMSMS Consortium. Cell, 2022. DOI: doi.org/10.1016/j.cell.2022.08.021. Only the summary is free of charge at this link. For an unformatted version of the full text please visit the page for this output on Edinburgh Research Explorer.