Role of the Gut Microbiome as Determinant of Depression in Multiple Sclerosis Subjects

Our overall hypothesis is that specific gut microbiome or gut-derived metabolites are associated with depression in pwMS. Mechanistically, the investigators further hypothesize that depression in pwMS is related to decreased abundance of gut bacteria with GABA-producing activities and/or with anti-inflammatory properties.

AIM 1. To determine if the presence of depression in pwMS is associated with specific gut microbiome, gut-derived metabolites or peripheral blood immune profiles.

The investigators will perform a cross-sectional study in clinically stable pwMS recruited at the John L. Trotter MS Center. The investigators will evaluate the presence of depression using the Quality of Life in Neurological Disorders (Neuro-Qol) depression scale, one of the 13 scales in the Neuro-Qol recently developed by the NIH using modern psychometric techniques and validated in pwMS. A total of 120 pwMS will be recruited: 60 with and 60 without depression based on the Neuro-Qol depression scale. At the study visit each participant will be asked to provide a stool sample for microbiome analyses and a blood sample for peripheral blood immunophenotyping. Potential confounders will be collected and treated as covariates in the analyses. These include: 1) degree of disability (EDSS); 2) treatment with anti-depressants and DMTs; 3) a 4-days food diary to evaluate diet composition; 4) the investigatorsight and height to calculate the BMI; 5) fatigue; 6) level of physical activity; 7) sleep quality.

AIM 1A. To determine if depression will correlate with specific gut microbiome or gut-derived metabolites profiles in pwMS.

Stool samples will be processed for microbiome sequencing and metabolome characterization.