Mechanistic characterisation of a novel oat-based postbiotic: microbiome modulation, barrier protection, and wound...

Postbiotics, the inactivated microorganisms and their products derived from fermentation, represent an evolution in the rapidly growing biotics industry and extend health benefits without the need for bacterial viability. In this study, we explored the potential of a novel oat-based postbiotic to provide health benefits by modulating the host immune system and gut microbiome. Two Lactobacillus species, Lactiplantibacillus plantarum 276 and Lacticaseibacillus rhamnosus GG, were used together to ferment 15% oat flour for 24 h at 37 °C followed by pasteurisation and freeze-drying to produce the oat-based postbiotic (OP). OP (1 mg/ml) was used to pretreat a mammalian intestinal epithelial cell line (Caco-2) for 1 h before stimulation with TNF-α and IL-1β (10 ng/ml each). The immuno-modulatory and barrier-supporting effect of OP were evaluated by measuring transepithelial electrical resistance (TEER), wound healing, and expression of cytokines genes (IL-6 and CXCL-8) as well as in a nematode (Caenorhabditis elegans) model. OP protected intestinal barrier integrity as measured by TEER in Caco-2 cells and in the C. elegans model. IL-6 and CXCL-8 expressions in OP pretreated cells were upregulated and OP promoted significant wound closure within 24 h. OP also markedly modulated the human gut microbiome as demonstrated by a 6.48-fold increase in native Bifidobacterium spp. in the in vitro human faecal model. Findings of this study suggest that OP is a novel, safe, stable, and effective intervention for foundational gut health and overall wellness.