Written by Joyce Smith, BS. This study demonstrates that multiple sclerosis is associated with a change in microbial diversity as demonstrated from sequenced fecal samples of 31 participating patients with relapsing-remitting multiple sclerosis.

Multiple sclerosis (MS) is an unpredictable, potentially disabling disease of the central nervous system. In MS, the immune system attacks the protective myelin that covers nerve fibers and impairs the conduction of signals in the affected nerves. This causes communication problems within the brain as well as between the brain and body.1

MS is a relapsing-remitting (RRMS) disease with bouts of attacks or relapses followed by varying degrees of recovery. The etiology of this immune-mediated disease is complex and poorly understood and encompasses both genetic and environmental factors. 2,3 People with MS have higher rate of constipation and fecal incontinence, 4 as well as increased gut permeability.5 There is also an increased incidence of inflammatory bowel disease (IBD) in these patients and often an autoimmune/allergic component in both MS patients and their families. 6

These factors suggest an important gut-CNS connection. Studies have shown that gut bacteria can even influence the integrity of the blood brain barrier. 7 Researchers hypothesized that gut microbiota may play a role in MS. Their objective was to prove that RRMS patients have a gut microbiota composition that is distinctly different from healthy controls.

Researchers isolated, sequenced and analyzed the microbiome in fecal samples of 31 patients with RRMS. They found the following similarities and differences between the gut microbiota of RRMS patients and healthy controls. They also documented the differences in the microbiota of patients that were in active and remission phases of RRMS.

  • Their results showed that gut microbiota of RRMS patients did not differ significantly from the healthy controls (P=0.73); however, when compared to healthy controls, those RRMS patients with active multiple sclerosis, showed a trend toward a decrease in gut diversity. (P=0.1
  • Patients with active MS showed a similar trend toward decreasing gut diversity (P=0.2) while patients in the remission phase of MS had a gut population similar to healthy controls.
  • Also the structure of microbiota differed significantly between RRMS patients (in both remission and active state) and healthy controls (P<0.001). The structure of the active state microbiota also differed significantly from that of the remission state (P=0.05) while the remission state microbiota were similar to the healthy controls (P=0.06).
  • The remission group of microbiota was composed of two subgroups: one that was similar to the active state, the other similar to the healthy controls.
  • The microbial community profile also differed between MS patients and healthy controls. MS patients had increased Psuedomonas, Mycoplana, Haemophilus, Blautia, and Dorea genera while healthy controls had increased Parabacteroides, Adlercreutzia and Prevotella genera.

Researchers clearly demonstrated that MS patients had dysbiosis of fecal microbiota in their gut. Because of the small sampling size of RRMS patients and healthy controls, researchers could not rule out the effect that smoking, family history, or treatment status may have had on the abundance of microbiota. They suggest that larger studies are needed in order to examine the functional changes that occur in intestinal microbiota over time and to evaluate their potential role in immune system response.

Source: Chen, J. et al. Multiple sclerosis patients have a distinct gut microbiota compared to healthy controls. Sci. Rep. 6, 28484; doi: 10.1038/srep28484 (2016).

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Posted August 30, 2016.

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