Fig. 5.

Proposed role of FA and FA metabolism in MS patients. First, FAs can serve as biomarkers of disease activity and therapeutic efficacy. Multiple FAs serological concentration can reflect disease activity, including intestinal barrier permeability, Treg–Th1 axis balance and EDSS score. A longitudinal cohort of pregnant MS patients indicates the predictive value of FAs ratio in determining risk of relapse. Moreover, after DMF treatment, drop of lymphocyte counts correlates the fluctuation of serological SFA and MUFA level. Second, FAs intake or metabolic state contributes to MS susceptibility. MS patients, long before onset, acquire a unique FA serological profile. Gut microbiome data indicates a preferentially decrease of SCFAs-producing bacteria in MS patients. Several FA metabolism-related enzyme single nucleotide polymorphisms (SNPs), and PUFAs intake patterns are related to MS incidence. Third, FAs are potential MS therapeutic targets. As FAs and related bio-mediators level are altered among MS patients, adequate supplementation helps to reduce MS incidence risk, annual relapse rate (ARR), clinical score, CNS pathology and quality of life (QOL). Fourth, FAs biological compositions are constituents of MS metabolic memory that would influence immune system. A significantly decreased level of adipose-resident oleic acid among MS patients leads to a pro-inflammatory transcriptional profile of Treg cells, which can be reversed by oleic acid supplementation. CIS clinically isolated syndrome, EDSS Expanded Disability Status Scale, FADS fatty acid desaturase