The researchers found that while children with MS had the same diversity of gut bacteria as the children without MS, there were differences in the abundance of specific species.
Multiple sclerosis (MS) is an autoimmune disease thought to be triggered by genetic and environmental factors, including infections.
In MS, the immune system destroys myelin - the protein insulation that surrounds the nerves of the spinal cord, brain, and optic nerve, causing the electrical impulses that travel to and from these areas to leak out.
As the disease progresses, symptoms - beginning with mild numbness in the limbs - gradually worsen, resulting in paralysis and blindness.
People with relapsing-remitting MS - the most common form of MS - experience symptom flare-ups interspersed with periods of recovery.
The human body contains 10 times more microbial cells than human cells, and over 90 percent of them live in the gut, where they help synthesize vitamins, regulate the immune system, and protect against infection.
Recent studies have suggested that gut bacteria may have a role in MS, but most of this evidence comes from research on animals.
While some studies of human adults have linked disruption of gut bacteria to MS, their evidence is muddied by the fact adults have a lifetime of exposures, making it difficult to pinpoint the role of gut bacteria specifically.
MS linked to pro-inflammatory gut microbes
The team behind the new research thought an investigation comparing gut bacteria of children with and without MS might help clarify the link. The team included members from the University of British Columbia (UBC) in Vancouver, Canada, the University of California-San Francisco (UCSF), and the University of Utah in Salt Lake City.
- There are approximately 2.5 million people with MS worldwide
- An estimated 10,000 new cases are diagnosed in the United States each year
- Most people with MS are diagnosed between 15-50 years of age.
For their pilot study, the researchers compared the gut bacteria of 18 children with relapsing-remitting MS with 17 healthy children without MS. The children (average age 13, ranging between 4-18 years) were patients at a UCSF pediatric clinic.
An analysis of the bacteria - obtained from stool samples - found that children with MS had the same diversity of gut bacteria as the children without MS. However, there were differences in the abundance of specific species.
The researchers found a link between MS and an increase in gut bacteria associated with inflammation, and a decrease in gut bacteria considered to be anti-inflammatory.
Specifically, "relative to controls, MS cases had a significant enrichment in relative abundance for members of the Desulfovibrionaceae (Bilophila, Desulfovibrio, and Christensenellaceae), and depletion in Lachnospiraceae and Ruminococcaceae," they note in their study paper.
First author Helen Tremlett, an associate professor in UBC's faculty of medicine, describes their preliminary findings as "intriguing."
"We also observed some similarities between our findings and other emerging gut microbiota studies in multiple sclerosis; whether these indicate a 'gut signature' of multiple sclerosis or of broader autoimmune disease remains to be determined."
Prof. Helen Tremlett
The authors suggest that a better understanding of the role that gut bacteria play in MS could help find new targets for treating the disease.