IDENTIFICATION OF NOVEL PROBIOTIC STRAINS WITH BENEFICIAL POTENTIAL IN GASTROINTESTINAL DISORDERS
Abstract
Objective: The goal is to identify promising bacterial strains against gastrointestinal disorders that will be tested in in vivo assays in the future. We have used an in vitro approach to compare the anti-inflammatory properties of 41 bacterial strains, including commercialized probiotics as benchmark controls.
Methods: Growth kinetics were determined by optical density and colony forming unit countings. All strains were recovered and cryoconserved at the beginning of their stationary phase. Bacterial supernatants were analyzed for short chain fatty acid and Arylhydrocarbon Receptor (AhR) agonists production, using gas chromatography and HepG2 Lucia reporter line respectively. Strains were then tested in vitro with equal multiplicity of infection: dosing of cytokines produced after co-incubation on TNF-alpha challenged HT-29 cells and non stimulated peripheral blood mononuclear cells (PBMC), and measures of TransEpithelial Electrical Resistance of TNF-alpha challenged Caco2 cells.
Results: 7 strains demonstrated acetate production and 10 strains demonstrated AhR agonists production. Coincubation on HT29 resulted in a 20% decrease of IL8 production for 6 strains; and coincubation on PBMC revealed a change in the TH1/TH2 profile through modulation of IL10 / IL12 production for 22 strains. 15 strains were able to restore the paracellular permeability of Caco2.
Conclusions: 41 strains were screened for parameters linked with intestinal disorders: production of anti-inflammatory metabolites, immunomodulation and capacity to restore the intestinal barrier function. Combining these data allowed a ranking of strains and selection of 4 promising ones that will be further tested in in vivo gastrointestinal disorder models.