P912 Increased Primary Bile Acids with Ileocolonic Resection Impact Ileal Inflammation and Gut Microbiota in Inflammatory Bowel Disease

Abstract Background A majority of Crohn’s disease (CD) patients require surgery. Ileitis recurs after most ileocolectomies and is a critical determinant for outcomes. The impact ileocolectomy-induced bile acid (BA) perturbations on intestinal microbiota inflammation are unknown. We characterized relationships between ileocolectomy, stool BA, microbiota, in inflammatory bowel (IBD). Methods Validated IBD clinical endoscopic assessments were prospectively collected. Matched primary secondary BA concentrations measured using Agilent Quadrupole Time Flight Liquid chromatography-mass spectrometry compared based ileocolectomy ileitis status. Primary thresholds evaluated area under the receiver operating characteristic curve analyses. In CD, remission was defined as SES-CD <3 or Rutgeerts <i2b. Ileal ER ileal ≤ 1 colonic SES-CD≤2 without any segment >1. UC, UC-ESS 1. Metagenomic sequencing profiled microbial composition function. Relationships assessed. Results 166 patients, elevated existed with ileocolectomy. With ileitis, only (795 nMol/g vs 398 nMol/g, p=0.009) higher to ileitis. optimal threshold (≥228nMol/g) identified multivariable analysis (OR=2.3, p=0.04). Similar (471 vs. 606 p=0.8) (382 242 p=0.2) inflammation. Microbial diversity (Shannon index, p=0.0006), Faecalibacterium prausnitzii O-acetylhomoserine aminocarboxypropyltransferase (MetY, p=0.0002) decreased BA. Amongst those had (p=0.01), F.prausnitzii MetY (p=0.04) reductions. Those both intermediate (p=0.002) high (≥228nMol/g, p=9.1e-11) ) reduced (Figure 1). low (<29.2nMol/g) similar (P=0.13). (p=0.02). Conclusion Elevated acids associated diversity, abundance, enzymatic expression (acetate L-methionine producing enzyme expressed by F.prausnitzii) factor these findings