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

Benef Microbes. 2019 Mar 13;10(2):137-147. doi: 10.3920/BM2018.0050. Epub 2018 Dec 21.


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 life (PAC-QoL)) was administered. A group of healthy subjects was enrolled as controls (HC). At V1, the mean serum 5-HT level in the whole patient group was significantly higher (P=0.027) than in HC subjects, while serum BDNF did not. At the end of probiotic administration (V4), 5-HT and BDNF levels were significantly lower than the initial values (V1) (P=0.008 and P=0.015, respectively). 5-HT and BDNF serum concentration were significantly associated (r=0.355; P=0.007). Neither 5-HT nor BDNF serum levels correlated with the CSS item scores and with the PAC-QoL. Lastly, the regression analysis demonstrated that the presence of the S allele of the 5-HTTLPR accounted for the reduction in the 5-HT concentration at V4. In conclusion, the long-term administration of LR DSM 17938 demonstrated that such a probiotic strain could improve FC by affecting 5-HT and BDNF serum concentrations.

Keywords: DSM 17938; 5-HT; BDNF; constipation; probiotics.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Aged
  • Brain-Derived Neurotrophic Factor / blood*
  • Brain-Derived Neurotrophic Factor / genetics
  • Constipation / pathology
  • Constipation / therapy*
  • Double-Blind Method
  • Female
  • Humans
  • Limosilactobacillus reuteri / growth & development*
  • Male
  • Middle Aged
  • Polymorphism, Single Nucleotide
  • Probiotics / administration & dosage*
  • Quality of Life
  • Serotonin / blood*
  • Serotonin Plasma Membrane Transport Proteins / genetics
  • Serotonin Receptor Agonists / blood*
  • Surveys and Questionnaires
  • Treatment Outcome
  • Young Adult


  • Brain-Derived Neurotrophic Factor
  • SLC6A4 protein, human
  • Serotonin Plasma Membrane Transport Proteins
  • Serotonin Receptor Agonists
  • Serotonin
  • BDNF protein, human