Multiple Sclerosis connected with a gut dysbiosis
Multiple sclerosis – an autoimmune disease!
Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS). MS is thought to be an autoimmune disease, with immune cells (T-cells) attacking the myelin peptides (layer which protects the nerves). As a result MS patients suffer from inflammation and neurodegeneration, manifesting in sensory, motor and/or cognitive deficits. The genesis of MS is complex, with both genetic and environmental factors playing major roles in pathogenesis. Genetic factors account for 30% of disease risk, resulting in 70% of environmental influences. Recent evidence suggests that the gut microbiome plays a major role in these 70% of environmental risks.
Analysis of the microbiome of patients with autoimmune diseases such as MS, type I diabetes, inflammatory bowel disease and rheumatoid arthritis has shown an altered microbiome in all diseases. All these autoimmune diseases have a common pattern: a decrease of beneficial bacteria and an increase of harmful bacteria.
In all studies the MS patients showed a dysbiosis
Different studies around the globe were conducted in order to find a specific bacterial pattern in MS patients. A comparison of these studies shows that in all studies the MS patients showed a dysbiosis. However, no specific bacterial pattern could be identified, meaning that no higher or lower abundance of specific bacterial families was found, but the microbiome as a whole has shifted to a state which induces inflammation. Consequently microbiome data must be taken with caution. Influences like the geographical location, genetics, methods of analysis and diets have to be considered. Instead of looking at the distinct bacteria research has to focus on the function of the changed bacterial population.
As soon as scientist would have revealed the functional bacterial shift in the gut of MS (and other autoimmune diseases) patients, therapies can be developed.
As for example one common pattern in MS patients was the low abundance of bacteria which are capable of the production of short-chain fatty acids (SCFA), such as the bacterium Prevotella or Bacteroides fragilis. Besides serving as energy source, SCFAs strongly interact with the immune system via down-regulation of inflammatory reactions.
The gut microbiota play an important role
Overall gut microbiota obviously play an important role in the development of MS by immune modulation of the host via the influence on different metabolic pathways such as the SCFA, bile acid, phytoestrogen and other pathways. What is now to further investigate, is the complex cross-talk between the different bacterial species, our metabolism and our immune system.
In the near future the treatment of the microbiome hopefully will be a therapy for MS!
Link to publication: Freedman et al., 2018