Objective biomarkers for clinical relapse in multiple sclerosis: a metabolomics approach

Abstract

Accurate determination of relapses in Multiple Sclerosis (MS) is important for diagnosis, classification of clinical course and therapeutic decision making, The identification of biofluid markers for MS relapses would add to our current diagnostic armamentarium and increase our understanding of the biology underlying the clinical expression of inflammation in MS. However, there is presently no biofluid marker capable of objectively determining MS relapses although some, in particular neurofilament-light chain, have shown promise. In this study, we sought to determine if metabolic perturbations are present during MS relapses, and, if so, identify candidate metabolite biomarkers and evaluate their discriminatory abilities at both group and individual levels, in comparison with neurofilament-light chain. High-resolution global and targeted 1H nuclear magnetic resonance metabolomics as well as neurofilament-light chain measurements were performed on the serum in four groups of relapsing-remitting MS (RRMS) patients, stratified by time since relapse onset: (1) in relapse (R), (2) last relapse (LR) ≥ 1 month (M) to < 6 M ago, (3) LR ≥ 6 M to < 24 M ago, and (4) LR ≥ 24 M ago. Two hundred and one RRMS patients were recruited: R (n = 38), LR 1–6 M (n = 28), LR 6–24 M (n = 34), LR ≥ 24 M (n = 101). Using supervised multivariate analysis, we found that the global metabolomics profile of R patients was significantly perturbed compared to LR ≥ 24 M patients. Identified discriminatory metabolites were then quantified using targeted metabolomics. Lysine and asparagine (higher in R), as well as, isoleucine and leucine (lower in R), were shortlisted as potential metabolite biomarkers. ANOVA of these metabolites revealed significant differences across the four patient groups, with a clear trend with time since relapse onset. Multivariable receiver operating characteristics analysis of these four metabolites in discriminating R versus LR ≥ 24 M showed an area under the curve of 0.758, while the area under the curve for serum neurofilament-light chain was 0.575. Within individual patients with paired relapse-remission samples, all four metabolites were significantly different in relapse versus remission, with the direction of change consistent with that observed at group level, while neurofilament-light chain was not discriminatory. The perturbations in the identified metabolites point towards energy deficiency and immune activation in MS relapses, and the measurement of these metabolites, either singly or in combination, are useful as biomarkers to differentiate relapse from remission at both group and individual levels.

Determination of CSF GFAP, CCN5, and vWF Levels Enhances the Diagnostic Accuracy of Clinically Defined MS From Non-MS Patients With CSF Oligoclonal Bands

“…NMR metabolomics is a cheap and rapid analysis method, requiring minimal sample preparation and with the advantage that a host of additional small molecules can be quantified in the same analysis. Indeed, we have shown that NMR metabolomics is able to identify relapse (38), predict conversion (16), and diagnose progression (39) in MS and so, in future, it may be possible to apply multiple tests to a single sample. Future work will develop a chip-based assay to measure only the top biomarkers identified here in the hopes of improving translatability of this method.…”

A metabolome-wide Mendelian randomization study prioritizes causal circulating metabolites for multiple sclerosis

“…Altered circulating levels of amino acids and gamma-glutamyl amino acids have been observed in MS patients 2, 3 . A higher serum level of lysine was observed in MS patients when compared to healthy controls 6 , and also in MS patients who are in relapse in comparison to those that are a few months after the last relapse 35 . The pattern for serine is more complex.…”

Early urinary candidate biomarkers and clinical outcomes of intervention in a rat model of experimental autoimmune encephalomyelitis

“…The other pathways are mostly related to the acute response except for asparagine pathway. Though its role in multiple sclerosis is unclear, asparagine may have roles in proper immune functioning and asparagine biosynthesis may be one of the main canonical pathways involved in multiple sclerosis [ 33 ]. The inhibition of asparagine endopeptidase greatly enhanced presentation of the myelin basic protein [ 34 ], which plays a key role in pathogenesis of multiple sclerosis.…”