MicroRNAs Expression in the Ileal Pouch of Patients with Ulcerative Colitis is Robustly Up-Regulated and Correlates with Disease phenotypes

Gene expression alterations are associated with disease behavior in inflammatory bowel disease (IBD). microRNAs (miRNAs) are dominant in the regulation of gene expression, and may affect IBD phenotype. Our aim was to assess mucosal miRNA expression in IBD and the correlation with intestinal inflammation. Sixty-one subjects were recruited. The ileum of unoperated UC patients was comparable with NC. There were significant miRNA expression alterations (fold change =2, corrected P =.05) in NP (n = 6), CP (n = 40) and CLDP (n = 139), but only two expression alterations were noted in CD. More than 90% of the altered miRNAs were up-regulated, and many were predicted to be associated with significantly decreased transcripts. miRNAs alterations were generally clustered with disease phenotypes. Ileal inflammation causes increased miRNA expression. miRNA alterations correlate with IBD phenotype, apparently by controlling the down-regulation of specific mRNAs. Overall design: Pouchitis is a model for ileal Inflammatory Bowel Disease (IBD) and may enable the detection of miRNAs associated with intestinal inflammation. Control/disease samples: Crohn''s-like disease of the pouch (CLDP), chronic pouchitis (CP-P), Ileal Crohn''s disease (IlealCD), normal control (NC), normal pouch (NP-P), ulcerative colitis (UC).