Epithelial IL-1R2 acts as a homeostatic regulator during remission of ulcerative colitis.

Ulcerative colitis (UC) is a chronic intestinal inflammatory disease that may undergo periods of activity followed by remission. We aimed to identify the endogenous regulatory mechanisms that may promote disease remission. Transcriptional and protein analysis of the intestinal mucosa revealed that the IL-1 decoy receptor, interleukin-1 receptor type 2 (IL1R2), was upregulated in remission compared with active UC and controls. We identified epithelial cells as being responsible for increased IL-1R2 production during remission. Expression of IL1R2 was negatively regulated by Wnt/beta-catenin signals in colonic crypts or epithelial stem cell cultures; accordingly, epithelial stem cells upregulated IL-1R2 upon differentiation. Blocking IL-1R2 in isolated colonic crypt cultures of UC patients in remission and T-cell cultures stimulated with biopsy supernatant from UC patients in remission boosted IL-1ß-dependent production of inflammation-related cytokines. Finally, IL1R2 transcription was significantly lower in patients that relapsed during a 1-year follow-up period compared with those in endoscopic remission. Collectively, our results reveal that the IL-1/IL-1R2 axis is differentially regulated in the remitting intestinal mucosa of UC patients. We hypothesize that IL-1R2 in the presence of low concentrations of IL-1ß may act locally as a regulator of intestinal homeostasis.

Value of endoscopy and MRI for predicting intestinal surgery in patients with Crohn's disease in the era of biologics.

OBJECTIVE: Severe endoscopic lesions (SEL) in patients with colonic Crohn's disease (CD) have been linked to higher risk of colectomy. The aims of this study were to reassess the predictive value of colonoscopy compared against MRI for requirement of resection surgery in patients with CD and determine the influence of current therapeutic options. DESIGN: In this single-centre, observational, prospective, longitudinal study, patients with an established diagnosis of CD and suspected activity were included. After baseline assessment, including colonoscopy and MRI, patients were followed until resection surgery or the end of study. RESULTS: 112 patients were eligible for analysis. Ulcers were present in 94/112 (84%) of patients at colonoscopy (SELs in 51/112 (46%)) and stenosis in 38/112 (34%). MRI identified ulcers in 79/112 (71%) of patients, stenosis in 36/112 (32%) and intra-abdominal fistulae in 20/112 (18%). Surgical resection requirements (29/112 (26%)) were not associated with the presence of SELs at colonoscopy. The presence of stenosis (p<0.001) or intra-abdominal fistulae (p<0.001) at MRI correlated with a higher risk of surgery. In the multivariate analysis, perianal disease (OR 9 (2 to 39), p=0.003), stenosis (OR 3.4 (1 to 11), p=0.04) and fistulae at MRI (OR 10.6 (2 to 46), p=0.002) increased the risk of abdominal resection surgery, while months under immunomodulators (OR 0.94 (0.90 to 0.98), p=0.002) and/or antitumor necrosis factor (anti-TNF) therapy (OR 0.97 (0.94 to 1), p=0.04) during follow-up decreased this risk. CONCLUSIONS: Perianal disease, stenosis and/or intra-abdominal fistulae at MRI independently predict an increased risk of resection surgery in patients with CD, whereas immunosuppressants and/or anti-TNF therapy reduce such risk. Under current therapeutic strategies, the presence of SELs is not a predictor of resection surgery in patients with CD.