Gut Microbiota Imbalance Discovered in Multiple Sclerosis Patients

A new study recently published in the journal PLOS One revealed that multiple sclerosis (MS) patients have a microbial imbalance (dysbiosis) in their gut microbiota that is most likely linked to the disease pathogenesis. The study is entitled “Dysbiosis in the Gut Microbiota of Patients with Multiple Sclerosis, with a Striking Depletion of Species Belonging to Clostridia XIVa and IV Clusters” and was developed by researchers at several institutes and universities in Japan where the incidence of MS has been increasing.

MS is a chronic, progressive neurodegenerative disorder that results from an attack on the central nervous system (brain, spinal cord and optical nerves) by the body’s own immune system, resulting in motor function impairment (coordination, balance, speech and vision), irreversible neurological disability and paralysis. The most frequent form of the disease is relapsing-remitting MS (RRMS), which is clinically characterized by recurring episodes of neurological symptoms. It is estimated that more than 2.3 million people in the world suffer from MS and there is currently no cure.

Studies on experimental autoimmune encephalomyelitis (EAE), a rodent model of MS that is used in the lab, have suggested that alterations in the gut microbiota are a potential risk factor for the development of MS. Interestingly, recent studies have shown that Clostridia clusters XIVa, IV, and Bacteroides fragilis bacteria in humans are able to induce specific regulatory immune T cells and suppress inflammatory conditions like EAE.

To investigate this hypothesis, researchers have now analyzed the gut microbiota of 20 Japanese patients with RRMS, 40 healthy Japanese individuals and an additional group of 18 healthy individuals. DNA isolated from fecal samples of the participants was analyzed for the bacterial 16S ribosomal RNA gene.

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Researchers found that MS patients had a moderate dysbiosis in their gut microbiota. They found significant changes in the abundance of 21 species between MS patients and healthy individuals, namely a reduction in species belonging to Bacteroidetes and Clostridia clusters XIVa and IV, which are known to have an anti-inflammatory action.

The research team concluded that there is indeed a relevant association between an altered gut microbiota and MS pathogenesis. The findings suggest that correcting the dysbiosis present in MS patients and controlling the gut microbiota could be an important therapeutic approach for MS prevention and treatment.