P910 Emerging role of IL-33/ST2 and Gut Microbiota axis in the inflammatory process of ulcerative colitis patients with ileal pouch-anal anastomosis

Abstract Background IL-33/ST2 axis and gut microbiota are important factors in the pathogenesis of IBD with a potential reciprocal influence. controls mucosal healing process during intestinal inflammation. Pouchitis, after restorative proctocolectomy ileal pouch-anal anastomosis, is most common complication. We aimed to explore correlation between cytokines inflammatory pouchitis. Methods 23 patients anastomosis were enrolled. 13 showed pouchitis 10 normal pouch. Mucosal samples collected from afferent loop Multiplex analysis for was performed. ELISA, western blot IHC run assess axis. Microbiota analyzed by 16S ribosomal RNA gene amplicon pyrosequencing. Pouchitis Disease Activity Index Histological Score calculated. Multivariate analyses generate transcriptional interaction networks identify biomarkers inflamed pouches. Results IL-1Ra, IL-6, IL-8, IL-17, IP-10, MCP-1, MIP-1a, MIP-1b increased pouch vs. No differences registered loop. In pouchitis, IL-7 resulted reduced pouch, no recorded. IL-33 ST2 protein levels significantly decreased Full-length, bioactive IL33, ST2L sST2 expressed all experimental groups; cleaved, less active form IL33 only stainings intense within ulcerated mucosa compared close proximity areas re-epithelialization. biodiversity (both at level). Lower Verrucomicrobia abundance Actinobacteria recorded vs Akkermansia muciniphila augmented Collinsella multivariate evidenced significant inverse e aereofaciens levels. Conclusion characterized divergent molecular pathways microbial populations specific pattern Our results suggest role driving wound anastomosis.