Gut Bacteria and MS: What's the Connection?

Researchers continue to find strong evidence that gut bacteria could play a role in MS

bacteria-icon-2316230 640Whether there are potential connections between our intestines and brain health, and what that could mean for the treatment and prevention of MS, has been a focus of research for several years now.  Two recently published studies add to this growing body of research and have found additional strong evidence that intestinal bacteria could play a role in MS.

The first study was published in the Proceedings of the National Academy of Sciences (PNAS) in August, 2017 and was led by Dr. Sergio Baranzini of the University of California, San Francisco. The researchers analyzed the microbiomes (microorganisms, such as bacteria, fungi, and viruses, in the intestine) of 71 MS patients and 71 healthy individuals. They found that two types of bacteria, Acinetobacter and Akkermansia, are quite rare in healthy people and more abundant in people with MS.

Their finding adds to prior studies which have found a difference between the gut bacteria of MS patients and healthy people. However, the researchers took their result to the next level. They wanted to try to understand whether having MS changes the bacteria in the gut, or whether it’s the reverse.  To do this, the team took the two kinds of bacteria, added them into healthy blood samples and then tested the blood.

The addition of these two bacteria to the blood resulted in increased levels of T helper cells (cells that activate immune attacks) and decreased levels of regulatory T cells (cells that suppress excessive immune responses, including autoimmune attacks like MS).  On top of this discovery, the Acinetobacter bacteria also mimic myelin molecularly (referred to as antigen mimicry). Myelin is the coating of nerve cells that the immune system attacks in MS.  This means that the bacteria might trigger immune attacks and could suggest a previously unknown environmental trigger for developing MS.

The second study, led by Hartmut Wekerle of Germany’s Max Planck Institute of Neurobiology and also published in PNAS in August, 2017, examined 34 sets of twins where only one of the  pair had MS. They transplanted gut microbes from the twins into lab mice and discovered that more of the mice that received the MS microbiome develop the mouse version of MS than the mice receiving the microbiome from the healthy twin.  This suggests the gut bacteria could be necessary for developing MS and could drive a microbiome-based therapeutic approach for treatment.

These studies add to the growing body of research related to potential connections between MS and gut bacteria.  While much more research will be necessary to further explore these findings and their implications, the research provides increasing knowledge of potential triggers of MS and could eventually lead to improved treatment or prevention of the disease.