Gut dysbiosis and lack of short chain fatty acids in a Chinese cohort of patients with multiple sclerosis

Background: Recent studies, mostly conducted in Western countries, showed that gut microbes are involved in the pathogenesis of multiple sclerosis (MS). Objective: The aim of this study was to investigate whether gut dysbiosis is relevant to the initiation and progression of MS in a Chinese population. Methods: Next-generation sequencing (NGS) and gas chromatography (GC) were integrated and used to compare the fecal bacterial communities and the short-chain fatty acid (SCFA) levels among relapsing-remitting MS (RAMS) patients (n = 34), neuromyelitis optica spectrum disorder (NMOSD) patients (n = 34), and healthy controls (HCs) (n = 34). T-cell profile analyses were performed by flow cytometry for MS patients and matched controls (n = 12). Results: (1) The gut microbiome of MS patients was characterized by an Increase of Streptococcus and a decrease of Prevotella_9; additionally, compared to NMOSD patients, Prevotella_9 was found to be much more abundant in MS patients. (2) A striking depletion of fecal acetate, propionate, and butyrate was observed in MS patients compared to HCs. (3) The abundance of Streptococcus was negatively correlated with the proportion of pTregs (P < 0.05) and positively correlated with Th17 cells (P < 0.05) in the peripheral blood, while the abundance of Prevotella_9 was negatively correlated with the Th17 cell frequency (P < 0.01), and the fecal SCFA level was positively correlated with pTreg frequency (P < 0.05). Conclusions: Gut dysbiosis and a lack of SCFAs exist in Chinese MS patients, which might be related to an aberrant immune response of MS; this relationship may have a diagnostic and therapeutic value for patients with MS.