Unveiling the influence of a probiotic combination of Heyndrickxia coagulans and Lacticaseibacillus casei on healthy human gut microbiota using the TripleSHIME® system.

Probiotics are host-friendly microorganisms that can have important health benefits in the human gut microbiota as dietary supplements. Maintaining a healthy gut microbial balance relies on the intricate interplay among the intestinal microbiota, metabolic activities, and the host's immune response. This study aims to explore if a mixture of Heyndrickxia coagulans [ATB-BCS-042] and Lacticaseibacillus casei [THT-030-401] promotes in vitro this balance in representative gut microbiota from healthy individuals using the Triple-SHIME® (Simulation of the Human Intestinal Microbial Ecosystem). Metataxonomic analysis of the intestinal microbes revealed that the probiotic mix was not causing important disruptions in the biodiversity or microbial composition of the three simulated microbiota. However, some targeted populations analyzed by qPCR were found to be disrupted at the end of the probiotic treatment or after one week of washout. Populations such as Cluster IV, Cluster XVIa, and Roseburia spp., were increased indicating a potential gut health-promoting butyrogenic effect of the probiotic supplementation. In two of the systems, bifidogenic effects were observed, while in the third, the treatment caused a decrease in bifidobacteria. For the health-detrimental biomarker Escherichia-Shigella, a mild decrease in all systems was observed in the proximal colon sections, but these genera were highly increased in the distal colon sections. By the end of the washout, Bacteroides-Prevotella was found consistently boosted, which could have inflammatory consequences in the intestinal context. Although the probiotics had minimal influence on most quantified metabolites, ammonia consistently decreased after one week of daily probiotic supplementation. In reporter gene assays, aryl hydrocarbon receptor (AhR) activation was favored by the metabolic output obtained from post-treatment periods. Exposure of a human intestinal cell model to fermentation supernatant obtained after probiotic supplementation induced a trend to decrease the mRNA expression of immunomodulatory cytokines (IL-6, IL-8). Overall, with some exceptions, a positive impact of H. coagulans and L. casei probiotic mix was observed in the three parallel experiments, despite inter-individual differences. This study might serve as an in vitro pipeline for the impact assessment of probiotic combinations on the human gut microbiota.

Evaluation of Four Multispecies Probiotic Cocktails in a Human Colonic Fermentation Model.

Bacteriotherapy represents an attractive approach for both prophylaxis and treatment of human diseases. However, combining probiotic bacteria in "cocktails" is underexplored, despite its potential as an alternative multi-target therapy. Herein, three-strain probiotic mixtures containing different combinations of Bacillus (Bc.) coagulans [ATB-BCS-042], Levilactobacillus (Lv.) brevis [THT 0303101], Lacticaseibacillus (Lc.) paracasei [THT 031901], Bacillus subtilis subsp. natto [ATB-BSN-049], Enterococcus faecium [ATB-EFM-030], and Bifidobacterium (Bf.) animalis subsp. lactis [THT 010802] were prepared. Four cocktails (PA: Bc. coagulans + Lv. brevis + Lc. paracasei, PB: Bc. subtilis subsp. natto + Lv. brevis + Lc. paracasei, PC: E. faecium + Lv. brevis + Lc. paracasei, PD: Bc. coagulans + Lv. brevis + Bf. animalis subsp. lactis) were tested using a short-term (72 h) simulation of the human colonic microbiota in a final dose of 6 × 109 CFU. All these probiotic mixtures significantly increased butyrate production compared to the parallel control experiment. PA and PB promoted a bifidogenic effect and facilitated lactobacilli colonization. Furthermore, reporter gene assays using the AhR_HT29-Lucia cell line revealed that fermentation supernatants from PA and PB notably induced AhR transactivity. Subsequent examination of the metabolic outputs of PA and PB in intestinal epithelial models using cell culture inserts suggested no significant impact on the transepithelial electrical resistance (TEER). Assessment of the expression of proinflammatory and anti-inflammatory cytokines, as well as AhR-related target genes in the Caco-2 cell monolayers indicated that PB's metabolic output upregulated most of the measured endpoints. This in vitro investigation evaluated the potential impact of four multispecies probiotic mixtures in the human colonic microbiota and identified a promising formulation comprising a combination of Bc. subtilis subsp. natto, Lv. brevis, and Lc. paracasei as a promising formulation for further study.