Plasma metabolomics can provide insights into the biochemical alterations underlying multiple sclerosis (MS) pathophysiology. Prior studies have been limited by small sample sizes and incomplete clinical annotation. The objective of this study was to identify metabolic signatures associated with MS diagnosis, disability, disease subtype, and inflammatory disease activity using a large, deeply phenotyped cohort.
The study conducted plasma metabolomic profiling in 411 patients with MS and 46,443 control participants. A targeted panel measured 162 metabolites, which were organized into 30 biologically related metabolite groups for analysis. Statistical approaches included regression modeling to test associations with clinical variables and differential network enrichment analysis to detect coordinated changes across metabolites. The investigators also examined 25 pre-diagnosis samples collected prior to subjects’ first demyelinating event to assess whether the MS metabolic signature was present before clinical onset.
After correction for multiple testing using the false discovery rate, 14 of the 30 metabolite groups showed significant associations with MS. The strongest positive associations with MS diagnosis were observed for atherogenic lipoproteins, glycine, cholines, and saturated fatty acids. Conversely, the strongest negative associations were for aromatic amino acids, branched-chain amino acids (BCAAs), alanine, and citrate. These bidirectional patterns indicate distinct shifts in both lipid and amino acid metabolic pathways in established MS compared with controls.
Differential network enrichment analysis identified two dysregulated subnetworks among the measured metabolites. One subnetwork encompassed amino acid and energy metabolism, while the other comprised lipid and lipoprotein metabolism. The presence of these coordinated subnetworks suggests that metabolic alterations in MS affect interconnected biochemical pathways rather than isolated analytes, pointing toward systemic metabolic remodeling in established disease.
Five metabolite groups were negatively associated with disability in patients with MS. These were: small high-density lipoprotein (HDL) particles, histidine, branched-chain amino acids, albumin, and aromatic amino acids. Negative association here indicates that lower levels of these metabolite groups correlated with greater disability. The specific relationship between these metabolic measures and clinical disability underscores potential relevance for pathways related to lipid transport, amino acid availability, and systemic protein status.
The study identified a significant association between the omega-6/omega-3 fatty acid ratio and recent clinical relapse. Quantitatively, the odds ratio for recent relapse was reported as 1.92 with an FDR-corrected p value of 0.030. The omega-6/omega-3 ratio was also nominally associated with future MRI activity, with a stronger signal observed among patients receiving moderate or high-efficacy disease-modifying therapy. These results suggest that relative balance of polyunsaturated fatty acids may relate to short-term inflammatory disease activity in treated patients. The report describes this as a novel association deserving further investigation.
The metabolomic signature that characterized established MS was not detectable in the 25 pre-diagnosis samples analyzed. That is, samples collected before participants’ first demyelinating event did not display the same group-level metabolic alterations observed in the cross-sectional cohort of patients with established MS. The authors therefore report that the identified metabolic changes appear to be features of established disease rather than readily detectable preclinical biomarkers, based on the limited pre-diagnosis sample set.
These data highlight coordinated dysregulation of amino acid and lipoprotein metabolism as hallmarks of established MS. Positive associations with atherogenic lipoproteins and saturated fatty acids alongside decreases in aromatic and branched-chain amino acids and citrate point to altered lipid handling and energy/amino acid pathways in patients with MS. The observed link between the omega-6/omega-3 ratio and recent relapse introduces a candidate metabolic marker of inflammatory activity that could inform mechanistic studies and, after validation, clinical research on dietary or metabolic modulation.
Limitations to note from the source: the work is reported as a preprint and has not undergone peer review. The pre-diagnosis sample set was small (25 individuals), limiting conclusions about early detection. As with any observational metabolomics study, measured associations do not establish causality and require replication and longitudinal validation.
Competing interests declared by the authors include institutional research support and consulting or speaking relationships for some investigators; the source lists those disclosures in detail. The study reports funding from the National Multiple Sclerosis Society (grant listed as FAN-2407-43752). The article is made available under a CC-BY 4.0 license and appears on bioRxiv as a preprint, indicating the findings have not been certified by peer review.
Note: All findings and numerical values reported here are drawn directly from the source preprint; further peer-reviewed confirmation is needed.