Summary: Scientists have discovered that people with multiple sclerosis (MS) have a clearly unbalanced oral microbiome, characterized by a loss of beneficial bacteria and an increase in microbes linked to inflammation. Using advanced genetic and metabolic profiling, researchers revealed that saliva from MS patients also had lower levels of hypotaurine, a molecule that supports antioxidant defense and nerve health.
These microbial and metabolic differences suggest that oral bacteria may contribute to immune dysregulation in MS. The findings could pave the way for simple saliva-based diagnostic tools and new treatments that restore healthy bacterial communities to support neurological health.
Key facts:
Distinctive oral microbiome: MS patients showed reduced levels of beneficial bacteria and increased inflammatory microbes in saliva. Metabolic signature: Lower levels of hypotaurine, a protective metabolite, were linked to neural health and antioxidant function. Clinical potential: Saliva testing may one day help diagnose or monitor MS, and restoring healthy oral bacteria could become a therapeutic strategy.
Source: University of Iowa
With advertisements everywhere for probiotic or prebiotic foods and supplements, most people are familiar with the gut microbiome (the trillions of bacteria, fungi, and viruses that colonize our digestive tract) and the idea that keeping our gut microbiome healthy improves our overall health.
But other areas of our body also host their own unique microbiomes, and researchers are now beginning to explore the role these microbial ecosystems play in health and disease.
Researchers at the University of Iowa Health Care have produced the most comprehensive genetic and metabolic analysis to date of the oral microbiome associated with multiple sclerosis (MS), a progressive autoimmune disease that damages nerves in the brain and spinal cord. They found that people with MS have a different (dysbiotic) oral microbiome compared to healthy people.
“While the gut microbiome has long been linked to MS, the oral microbiome, the rich microbial ecosystem in our mouth, has received much less attention, even though it is the second most diverse microbiome in the human body and has been linked to other neurological diseases, such as Alzheimer’s disease, and inflammatory diseases, such as rheumatoid arthritis,” says Ashutosh Mangalam, PhD, UI pathology professor. and lead author of the new study, which was recently published in the journal npj Bioflims and Microbiomes.
“Your mouth can reveal more about your overall health than you think,” he adds. “Our study shows that people with MS have measurable differences in the bacteria and metabolites found in their saliva. And it’s not just about losing some good bacteria; it suggests that there is a deterioration of the oral ecosystem in people with MS.”
While there are treatments that can slow MS, which causes muscle weakness, balance problems, and problems with vision and thinking, there is currently no cure for MS.
The knowledge gained from the new study could eventually help doctors develop simple saliva-based tests to detect or monitor MS and may open the door to new classes of MS treatments that replace or restore healthy bacteria.
MS characterized by the loss of good bacteria and the enrichment of bad bacteria.
Mangalam and his team used rapid metagenomic sequencing and untargeted metabolomics to study how changes in the entire community of bacteria in the mouth and the small molecules (metabolites) these organisms produce could influence MS.
They analyzed the saliva of 50 people with relapsing-remitting MS (RRMS), the most common form of MS, and 50 healthy controls. Compared to healthy people, people with MS had an altered oral microbiome.
This imbalance was primarily characterized by a loss of beneficial “early colonizing” bacteria, such as Streptococcus and Actinomyces, which are the building blocks of a healthy oral community, and an increase in bacteria with the potential to cause disease, including Fusobacterium nucleatum, Porphyromonas gingivalis, and several Prevotella species.
Also different was the metabolic profile of saliva, a measure of small molecules (metabolites) produced by both the patient and the bacteria. People with MS had reduced levels of a protective metabolite called hypotaurine, which is involved in antioxidant defense and nerve health. The study suggests that decreased hypotaurine levels are likely related to altered bacteria in the oral microbiome of MS.
Together, these findings suggest that oral microbial and metabolic changes may contribute to inflammation and disease processes in MS.
The researchers also developed a new machine learning approach called thematic modeling that allowed them to identify groups of bacteria that coexist as communities. This analysis uncovered microbial networks that are unique to healthy individuals and showed that five microbial communities were significantly lost in MS patients. This loss suggests a fundamental breakdown in the cooperative microbial network that maintains oral health.
“This multi-omics approach revealed how bacterial composition, function and metabolite profiles are interconnected, highlighting specific bacterial taxa and metabolic signatures that may shape inflammation and immune dysregulation in MS,” says Mangalam.
“These findings provide one of the most detailed views to date into the relationship between oral microbes, bacterial function and host metabolism in MS. The results expand our understanding of MS beyond the gut and brain and highlight the mouth as another important site of immunomicrobial interaction.”
The oral microbiome offers opportunities for new diagnostics and therapies
The new findings could lead to better ways to diagnose, monitor and even treat MS.
Because saliva collection is simple and noninvasive, the oral microbiome and metabolome could become valuable biomarkers for monitoring disease activity or response to treatment.
For example, microbiome profiling could be used to create a diagnostic signature for MS, and measuring hypotaurine levels in saliva could be a simple, non-invasive biomarker to aid in the diagnosis or monitoring of the disease.
Additionally, since the oral microbiome is easier to access and manipulate than the gut microbiome, the findings could open the door to a new class of MS treatments that replace or restore healthy bacteria to improve disease management and patient outcomes.
The multidisciplinary research team included scientists from the UI Carver School of Medicine, School of Dentistry, School of Public Health, School of Nursing and Holden Comprehensive Cancer Center. In addition to Mangalam, the team included Rachel Fitzjerrells, lead author and graduate student in Mangalam’s lab, Leeann Aguilar Meza, Meeta Yadav, Heena Olalde, Mishelle Paullus, Jemmie Hoang, Catherine Cherwin, Tracey Cho, Grant Brown, and Sukirth M. Ganesan.
Funding: The research was funded in part by grants from the National Institutes of Health.
Key questions answered:
A: Researchers found that people with multiple sclerosis have an altered oral microbiome characterized by a loss of beneficial bacteria and an increase in microbes linked to inflammation. This microbial imbalance, or dysbiosis, can contribute to immune dysfunction that worsens the symptoms and progression of MS.
A: The study identified unique saliva biomarkers in people with MS, including reduced levels of the protective molecule hypotaurine, which supports nerve health and antioxidant defense. These findings suggest that simple saliva tests could one day help detect or monitor MS activity based on metabolic and microbial signatures.
A: The mouth is home to one of the most complex microbial ecosystems in the body, and this study shows that it plays a key role in systemic inflammation related to multiple sclerosis. By mapping how oral bacteria interact with immune and metabolic pathways, scientists are discovering how microbial imbalances in the mouth can influence the brain and nervous system.
About this multiple sclerosis research news
Author: Jennifer Brown
Source: University of Iowa
Contact: Jennifer Brown – University of Iowa
Image: Image is credited to Neuroscience News.
Original research: Open access.
“Multiple sclerosis patients present with oral dysbiosis with decreased early colonizers and lower hypotaurine levels” by Ashutosh Mangalam et al. npj Biofilms and microbiomes
Abstract
Patients with multiple sclerosis present oral dysbiosis with decreased early colonizers and lower levels of hypotaurine.
Although gut microbiome dysbiosis is implicated in the pathobiology of multiple sclerosis (MS), the role of the oral microbiome (OM), the second largest microbiome, remains poorly understood.
Furthermore, while the salivary metabolome has been linked to other neurodegenerative diseases; Its role in people with relapsing-remitting MS (pwRRMS), the most prevalent form of MS, is unknown.
Combining shotgun metagenomics with untargeted metabolomics, we identified a reduced abundance of several early colonizing species, including Streptococcus and Actinomyces, in pwRRMS and an enrichment of bacteria with pathogenic potential, including Fusobacterium nucleatum, Porphyromonas gingivalis, and several Prevotella species. pwRRMS had an altered metabolite profile including decreased hypotaurine compared to healthy controls.
Therefore, we report an altered oral microbiome and metabolome in pwRRMS that could contribute to the pathobiology of MS.
These findings offer potential microbiome- and metabolome-based diagnostic biomarkers for MS and pave the way for new therapeutic interventions to improve disease management and patient outcomes.
