Prebiotic Enhancement of Intestinal Adaptation in Piglets With Short Bowel Syndrome is Associated with Microbial and Enteroendocrine Modifications

Abstract

BackgroundShort bowel syndrome is a costly condition affecting very low birth weight, premature infants and is associated with microbial dysbiosis. Microbially derived short chain fatty acids (SCFA) stimulate enteroendocrine secretion of glucagon‐like peptide 2 (GLP‐2), an intestinotrophic hormone. Hence, leverage of the intestinal microbiota to stimulate enteroendocrine driven intestinal adaptation requires investigation.ObjectiveThe aim of this study was to determine the mechanism by which prebiotic (short chain fructooligosaccharides, scFOS), probiotic (Lactobacillus rhamnosus GG, LGG), and synbiotic modify microbial stimulation of the enteroendocrine system to enhance intestinal adaptation in a neonatal piglet model of intestinal failure.MethodsNeonatal piglets (48 hours old, n = 38) underwent 80% jejunoileal resection and jugular catheter placement. Piglets received 80% parenteral and 20% enteral nutrition (EN) for 7 days and received 1 of 4 treatments: (1) control (CON), unsupplemented EN; (2) prebiotic (PRE), 10g scFOS/L EN; (3) probiotic (PRO), 10^9 CFU LGG/L EN, or (4) synbiotic (SYN), scFOS + LGG. Bacterial 16s rRNA genes (V3–V5 region) were amplified from the distal ileum and proximal colon and sequenced on the Illumina MiSeq system. qPCR was used to quantify expression of genes associated with enteroendocrine function. Multiple regression analysis was performed to assess the relationship of data to markers of intestinal adaptation. Statistical significance was determined at p < 0.05.ResultsIn the ileum, SYN increased expression of the SCFA transporters monocarboxylate transporter 1 (MCT1) and sodium monocarboxylate transporter 1 (SMCT1). In the colon, SYN increased MCT1, but PRE and PRO decreased SMCT1. SYN increased expression of SCFA‐responsive free fatty acid receptors 2 and 3 (FFAR2, FFAR3) in the ileum while PRO decreased FFAR2 in the colon. PRE and PRO decreased expression of dipeptidyl peptidase‐4 (DPP‐IV, the enzyme that inactivates GLP‐2) in the ileum but PRO decreased expression of GLP‐2 receptor (GLP‐2R) in both ileum and colon. PRO decreased expression of trophic hormone insulin‐like growth factor 1 (IGF‐1) and IGF‐1 receptor (IGF‐1R) in the colon. PRO also decreased expression of caudal‐type homeobox transcription factor 2 (CDX2, a marker of intestinal differentiation) in both ileum and colon.Multiple regression analysis identified the following factors as the most important covariates of markers of intestinal adaptation (top 3 listed) in the ileum: villus height with D‐lactate producing Lactobacillus abundance, Enterococcus faecalis abundance, and IGF‐1R (r^2 = 0.53); crypt depth with IGF‐1R, FFAR2, and MCT1 (r^2 = 0.58); proliferation with IGF‐1, GLP‐2R, and FFAR2 (r^2 = 0.61). In the colon: crypt depth with IGF‐1R, FFAR2, and proglucagon expression (r^2 = 0.63); proliferation with CDX2, IGF‐1R, and IGF‐1 (r^2 = 0.67).ConclusionsThese data demonstrate that intestinal adaptation is associated with a complex interaction between the intestinal microbiota and enteroendocrine system in a segment‐dependent fashion. Interestingly, SYN induced changes in enteroendocrine regulation that were unique from PRE and PRO. Microbial activity may contribute both positively (butyrate producing bacteria enhancing proliferation) and negatively (E. faecalis diminishing villus height). Future research should determine how various microbial products impact each step of enteroendocrine regulation specifically.