The intestinal microbiota may become a target for therapy in the fight against multiple sclerosis (MS). The results of several studies showed its involvement in the onset of immune anomalies associated with myelin loss.
MS, an autoimmune disorder characterized by loss of the myelin sheath surrounding central nervous system (CNS) neurons, affects around 80,000 people in France and probably more than 2 million worldwide. Studies designed to clarify its pathophysiological mechanisms have largely focused on immunity and the brain, but its etiology remains an enigma.
Intestinal infections suspected
Genetic and environmental factors are suspected. Among them, intestinal infections have attracted particular attention because they provoke immune-system dysfunction. More broadly, a new avenue of investigation is exploring the potential links between MS and the intestinal microbiota, which stimulates autoantigens to induce autoimmune demyelinization1.
A different microbiota
Clinical study results showed associations between gut flora and MS, with patients having, for example, Methanobrevibacter and Akkermansia overrepresentations and Butyricimonas underrepresentation, with modified expressions of genes involved in dendritic cell maturation and several immune-signaling pathways2. Using mouse models, researchers demonstrated that the gut flora is required for MS to develop. Segmented filamentous bacteria in the microbiota induce the production of MS-associated proinflammatory T-lymphocytes in the brain and, conversely, gut flora changes promote attenuation of those lymphocytes’ cytokine production3.
A step towards the use of probiotics?
In practice, consuming the yeast Candida kefyr alleviates MS severity in mice, by reducing the level of inflammation4 . A recent review on the topic proposes the intestinal microbiota as a potential target for MS treatment and prevention5 .
1. Berer K et al. Commensal micro- biota and myelin autoantigen cooperate to trigger autoimmune demyelination. Nature. 2011;479:538-41. http://www.nature.com/nature/journal/v479/n7374/full/nature10554.html
2.Sushrut Jangi et al. Alterations of the human gut microbiome in multiple sclerosis. Nature Communications 2016 online. http://www.nature.com/articles/ncomms12015
3. Lee YK et al. Proinflammatory T-cell responses to gut microbiota promote experimental autoimmune encephalomyelitis. Proc Natl Acad Sci USA. 2011;108:4615-22. https://www.ncbi.nlm.nih.gov/pubmed/20660719
4. Takata K et al. Dietary yeasts reduce inflammation in central nerve system via microflora. Ann Clin Transl Neurol. 2015;2:56-66. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4301675/
5. Glenn Justin D. Emerging Concepts on the Gut Microbiome and Multiple Sclerosis. Journal of Interferon & Cytokine Research 2016 May. Volume 36 Issue 6 http://online.liebertpub.com/doi/abs/10.1089/jir.2015.0177?journalCode=jir