Oral Spore-Based Probiotic Supplementation Alters Post-Prandial Expression of mRNA Associated with Gastrointestinal Health

<b>Background/Objectives</b>: Unregulated post-prandial dietary endotoxemia may accumulate over time and underlie the development of chronic disease (e.g., leaky gut, inflammatory bowel disease, etc.), for which oral probiotic supplementation may be a prophylactic. The purpose of this study was to determine if 45 d of oral spore-based probiotic supplementation altered gastrointestinal-associated mRNA expression following a high-fat meal. <b>Methods</b>: A subset of apparently healthy individuals from a larger study who had dietary endotoxemia at baseline completed 45 d of supplementation with either a placebo (rice flour; <i>n</i> = 10) or spore-based probiotic (Megasporebiotic™; Novonesis, Kongens Lyngby, Denmark; <i>Bacillus indicus</i> (HU36™), <i>Bacillus subtilis</i> (HU58™), <i>Bacillus coagulans</i> (SC208™), and <i>Bacillus licheniformis</i> (SL-307), and <i>Bacillus clausii</i> (SC109™); <i>n</i> = 10). Venous blood was collected in Paxgene RNA tubes prior to (PRE), 3 h, and 5 h after consumption of a high-fat meal (85% of the daily fat RDA and 65% of the daily calorie needs). Total RNA was analyzed for 579 mRNAs of interest (Nanostring nCounter Sprint; Seattle, WA, USA). After normalization to housekeeping controls and calculation of differential expression relative to PRE and controlled for FDR, 15 mRNAs were determined to be significantly changed at either 3 h and/or 5 h post-prandial in the probiotic group but not in the placebo group. <b>Results</b>: Significant mRNA expressions were associated with gastrointestinal tract barrier function (four mRNAs: BATF3, CCR6, CXCR6, and PDCD2), gastrointestinal immunity (four mRNAs: CLEC5A, IL7, CARD9, and FCER1G), or future IBD risk (seven mRNAs: PD-L1, CSF1R, FAS, BID, FADD, GATA3, and KIR3DL). <b>Conclusions</b>: Collectively, the present findings may support the notion that post-prandial immune response to eating is enhanced following 45 d of probiotic supplementation.