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ObjectiveDietary fibres are essential for maintaining microbial diversity and the gut microbiota can modulate host physiology by metabolising the fibres. Here, we investigated whether the soluble dietary fibre oligofructose improves host metabolism by modulating bacterial transformation of secondary bile acids in mice fed western-style diet.DesignTo assess the impact of dietary fibre supplementation on bile acid transformation by gut bacteria, we fed conventional wild-type and TGR5 knockout mice western-style diet enriched or not with cellulose or oligofructose. In addition, we used germ-free mice and in vitro cultures to evaluate the activity of bacteria to transform bile acids in the caecal content of mice fed with western-style diet enriched with oligofructose. Finally, we treated wild-type and TGR5 knockout mice orally with hyodeoxycholic acid to assess its antidiabetic effects.ResultsWe show that oligofructose sustains the production of 6α-hydroxylated bile acids from primary bile acids by gut bacteria when fed western-style diet. Mechanistically, we demonstrated that the effects of oligofructose on 6α-hydroxylated bile acids were microbiota dependent and specifically required functional TGR5 signalling to reduce body weight gain and improve glucose metabolism. Furthermore, we show that the 6α-hydroxylated bile acid hyodeoxycholic acid stimulates TGR5 signalling, in vitro and in vivo, and increases GLP-1R activity to improve host glucose metabolism.ConclusionModulation of the gut microbiota with oligofructose enriches bacteria involved in 6α-hydroxylated bile acid production and leads to TGR5-GLP1R axis activation to improve body weight and metabolism under western-style diet feeding in mice.

Background and aimsTeduglutide, a GLP-2 analogue, may restore intestinal structural and functional integrity by promoting repair and growth of the mucosa and reducing gastric emptying and secretion, thereby increasing fluid and nutrient absorption in patients with short bowel syndrome (SBS). This 24-week placebo-controlled study evaluated the ability of teduglutide to reduce parenteral support in patients with SBS with intestinal failure.MethodsIn 83 patients randomised to receive subcutaneous teduglutide 0.10 mg/kg/day (n=32), 0.05 mg/kg/day (n=35) or placebo (n=16) once daily, parenteral fluids were reduced at 4-week intervals if intestinal fluid absorption (48 h urine volumes) increased ≥10%. Responders were subjects who demonstrated reductions of ≥20% in parenteral volumes from baseline at weeks 20 and 24. The primary efficacy end point, a graded response score (GRS), took into account higher levels and earlier onset of response, leading to longer duration of response. The intensity of the response was defined as a reduction from baseline in parenteral volume (from 20% to 100%), and the duration of the response was considered the response at weeks 16, 20 and 24. The results were tested according to a step-down procedure starting with the 0.10 mg/kg/day dose.ResultsUsing the GRS criteria, teduglutide in a dose of 0.10 mg/kg/day did not have a statistically significant effect compared with placebo (8/32 vs 1/16, p=0.16), while teduglutide in a dose of 0.05 mg/kg/day had a significant effect (16/35, p=0.007). Since parenteral volume reductions were equal (353±475 and 354±334 ml/day), the trend towards higher baseline parenteral volume (1816±1008 vs 1374±639 ml/day, p=0.11) in the 0.10 mg/kg/day group compared with the 0.05 mg/kg/day group may have accounted for this discrepancy. Three teduglutide-treated patients were completely weaned off parenteral support. Serious adverse events were distributed similarly between active treatment groups and placebo. Villus height, plasma citrulline concentration and lean body mass were significantly increased with teduglutide compared with placebo.ConclusionsTeduglutide was safe, well tolerated, intestinotrophic and suggested pro-absorptive effects facilitating reductions in parenteral support in patients with SBS with intestinal failure.ClinicalTrials.gov numberNCT00172185.

BackgroundShorter half-life glucagon-like peptide-1 receptor agonists (GLP-1 RAs) delay gastric emptying (DGE) more than GLP-1 RAs with longer half-lives. DGE is a known risk factor for gastro-oesophageal reflux disease (GERD) and its complications.AimTo determine whether short-acting or long-acting GLP-1 RAs are associated with an increased risk of new GERD or GERD-related complicationsDesignWe used the TriNetX global database to identify adult patients with type 2 diabetes mellitus and generated two cohorts totalling 1 543 351 patients on (1) GLP-1 RA or (2) other second-line diabetes medication. Using propensity-score matching, Kaplan-Meier Analysis and Cox-proportional hazards ratio (HR), we analysed outcomes and separately examined outcomes in patients starting short-acting (≤1 day) and long-acting (≥5 days) GLP-1 RAs.Results177 666 patients were in each propensity-matched cohort. GLP-1 RA exposure was associated with an increased risk (HR 1.15; 95% CI 1.09 to 1.22) of erosive reflux disease (ERD). However, this was solely due to short-acting (HR 1.215; 95% CI 1.111 to 1.328), but not long-acting (HR 0.994; 95% CI 0.924 to 1.069) GLP-1 RA exposure. Short-acting GLP-1 RAs were also associated with increased risk of oesophageal stricture (HR 1.284; 95% CI 1.135 to 1.453), Barrett’s without dysplasia (HR 1.372; 95% CI 1.217 to 1.546) and Barrett’s with dysplasia (HR 1.505; 95% CI 1.164 to 1.946) whereas long-acting GLP-1 RAs were not. This association persisted in sensitivity analyses, and when individually examining the short-acting GLP-1 RAs liraglutide, lixisenatide and exenatide.ConclusionStarting shorter-acting GLP-1 RAs is associated with increased risks of GERD and its complications.

ObjectiveFood intake normally stimulates release of satiety and insulin-stimulating intestinal hormones, such as glucagon-like peptide (GLP)-1. This response is blunted in obese insulin resistant subjects, but is rapidly restored following Roux-en-Y gastric bypass (RYGB) surgery. We hypothesised this to be a result of the metabolic changes taking place in the small intestinal mucosa following the anatomical rearrangement after RYGB surgery, and aimed at identifying such mechanisms.DesignJejunal mucosa biopsies from patients undergoing RYGB surgery were retrieved before and after very-low calorie diet, at time of surgery and 6 months postoperatively. Samples were analysed by global protein expression analysis and Western blotting. Biological functionality of these findings was explored in mice and enteroendocrine cells (EECs) primary mouse jejunal cell cultures.ResultsThe most prominent change found after RYGB was decreased jejunal expression of the rate-limiting ketogenic enzyme mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (mHMGCS), corroborated by decreased ketone body levels. In mice, prolonged high-fat feeding induced the expression of mHMGCS and functional ketogenesis in jejunum. The effect of ketone bodies on gut peptide secretion in EECs showed a ∼40% inhibition of GLP-1 release compared with baseline.ConclusionIntestinal ketogenesis is induced by high-fat diet and inhibited by RYGB surgery. In cell culture, ketone bodies inhibited GLP-1 release from EECs. Thus, we suggest that this may be a mechanism by which RYGB can remove the inhibitory effect of ketone bodies on EECs, thereby restituting the responsiveness of EECs resulting in increased meal-stimulated levels of GLP-1 after surgery.

Fuchs et al present two possible explanations which are not mutually exclusive: on the one hand, LCA and DCA are the two most potent endogenous agonists for the membrane-bound BA receptor Takeda G protein-coupled receptor 5 (TGR5) and increased TGR5 signalling after colesevelam treatment leads to the secretion of the enteroendocrine peptide glucagon-like peptide 1 (GLP-1) from the large intestine.2 Since GLP-1 receptor signalling has protective effects on cholangiocytes,3 4 the authors suggest that this pathway contributes to the phenotypic improvements in the liver. In the Mdr2−/− model, pharmacological inhibition of ASBT can efficiently reduce liver damage and serum liver enzymes.5 6 Mechanistically, inhibition of ABST has effects on intestinal BA signalling that are overlapping, but distinct from the effects of BA sequestration: similar to resin treatment, ASBT inhibition blocks intestinal reuptake of BAs in the ileum (where ASBT is predominantly expressed) leading to decreased signalling via the intracellular BA receptor farnesoid X receptor (FXR) and decreased expression of its target gene FGF15.5 However, after microbiota-dependent deconjugation in the colon, a certain proportion of BAs are thought to enter the cells independently of active transport via ASBT and therefore signal via both extracellular (TGR5) and intracellular receptors (FXR). ASBT, apical sodium-dependent bile acid transporter; CYP7A1, cholesterol 7 alpha-hydroxylase; FGF15/19, fibroblast growth factor 15/19; FGFR4, fibroblast growth factor receptor 4; FXR, farnesoid X receptor; GLP-1, glucagon-like peptide 1; OCA, obeticholic acid; TGR5, Takeda G protein-coupled receptor 5. Pharmacological inhibition of apical sodium-dependent bile acid transporter changes bile composition and blocks progression of sclerosing cholangitis in multidrug resistance 2 knockout mice.