Functional potential of gut microbiome may be disturbed in those with pediatric-onset MS

Individuals with pediatric-onset MS may exhibit disturbances in their gut microbiome, according to study results published in Neurology.

“With the use of metagenomics, it is possible to survey all the genes present in the gut microbiome and infer the abundance of microbial functions,” Ali I. Mirza, MSc, of the department of medicine at the University of British Columbia in Canada, and colleagues wrote. “A higher relative abundance of a specific gene also implies a higher potential of the gut microbiome to produce a related product. While other ‘omics, such as metabolomics and proteomics, provide a survey of functional products, they alone do not provide information on the functional potential because gene products are not always expressed or detected.”

According to the researchers, data are lacking on the functional potential of the gut microbiome in pediatric-onset MS. In the current study, they conducted metagenomic analyses of stool samples from 20 patients with MS (mean age at symptom onset, 13.6 years) according to McDonald criteria with symptom onset at an age younger than 18 years who enrolled in the Canadian Pediatric Demyelinating Disease Network. They compared these stools with those of 20 controls matched by sex, age, stool consistency and race. Further, they estimated microbial taxonomy and functional potentials via metagenomic reads derived from stool samples and compared them by disease status and exposure to disease-modifying drug (DMD) based on alpha-diversity, relative abundance and prevalence. A total of eight individuals with MS were DMD naive. Participants with MS and controls had a mean age at stool sample of 16.1 years and 15.4 years, respectively, and 80% were girls.

Results showed no difference between alpha-diversity of enzymes and proteins based on disease or DMD status (P > .2); however, the researchers noted differences in metabolic pathways, gene annotations and microbial taxonomy. Compared with controls, patients with MS had higher methanogenesis prevalence (OR = 10; P = .044) and Methanobrevibacter abundance but lower homolactic fermentation abundance. Patients with MS who were DMD-naive had lower phosphate butyryltransferase compared with DMD-exposed patients with MS.

“Our findings can be considered as hypotheses-generating, worthy of validation and further investigation, preferably in large longitudinal studies capable of establishing the potential causal relationship of the gut microbiome with MS, and the contribution of other factors, such as dietary patterns,” Mirza and colleagues wrote. “The relative rarity of pediatric-onset MS is such that multisite collaborative efforts will be required, such as enrollment of participants and accrual of samples through established networks of pediatric clinics. Ultimately, this study advances understanding surrounding the potential association of the microbiome functions in individuals with MS.”