Effects of long-term administration of Lactobacillus reuteri DSM-17938 on circulating levels of 5-HT and BDNF in adults with functional constipation

Accumulated evidence shows that some probiotic strains ameliorate functional constipation (FC) via the modulation of specific gastrointestinal peptide pathways. The aims of this study were to investigate: (1) the effects of long-term administration of Lactobacillus reuteri (LR) DSM 17938 on the serum levels of serotonin (5-HT) and brain-derived neurotrophic factor (BDNF); (2) the possible link between 5-HT, BDNF, and specific constipation-related symptoms; (3) whether genetic variability at the 5-HTT gene-linked polymorphic region (5-HTTLPR) and BDNF Val66Met loci could be associated with serum 5-HT and BDNF variations. LR DSM 17938 was administered to 56 FC patients for 105 days in a randomised, double-blind manner. The fasting blood samples were collected during the randomisation visit (V1), at day 15 (induction period, V2), day 60 (intermediate evaluation, V3), and day 105 (V4) and the Constipaq questionnaire (the sum of Constipation Scoring System (CSS) and patient assessment constipation quality of l...