Fecal markers in Multiple Sclerosis Sex makes the difference

Abstract Background. Multiple Sclerosis (MS) is primarily considered as a neuro-inflammatory CNS disease. Yet, experimental data suggest a role for gut microbiota and microbial products like short chain fatty acids (SCFA) in the pathogenesis of MS. Very recently a high-ranked publication reported beneficial effects of propionate, a SCFA, in MS patients. Based on experimental and preliminary human data, we hypothesized that not only the gut microbiota but also microbial products and fecal inflammatory markers might be altered in MS.Methods. In a pilot study, we investigated fecal markers (short chain fatty acids, calprotectin) as well as clinical markers in patients with relapsing-remitting MS (RRMS) under different therapeutic regimes and compared the results to age-matched control subjects.Results. We observed a non-significant reduction in fecal SCFA in RRMS patients compared to control subjects. Fecal calprotectin concentrations did not differ significantly between MS patients and control subjects. We observed a significant reduction in fecal SCFA concentrations in women compared to men.Conclusions. We conclude that the observed sex-associated difference in fecal SCFA concentrations might be a contributing factor in the pathogenesis of MS, especially when taking into account the female predominance in MS. We suggest investigating the role of SCFA in MS in a longitudinal study (starting in drug-naïve patients) in larger cohorts of MS patients with defined therapeutic regimes. Such a study would allow to distinguish between drug effects and disease-immanent effects and might help to identify a potentially modifiable sex-associated contributing factor in MS.Trial registration. Registered by the local Ethics Committee (Reg.Nr. 81/18, Ethikkommission der Aerztekammer des Saarlandes, Saarbruecken, Germany).