BACKGROUND. Crohn’s disease (CD) is highly heterogeneous, due in large part to variability in cellular processes that underlie the natural history of CD, thereby confounding effective therapy. There is a critical need to advance understanding of the cellular mechanisms that drive CD heterogeneity. METHODS. We performed small RNA sequencing of adult colon tissue from CD and NIBD controls. Colonic epithelial cells and immune cells were isolated from colonic tissues, and microRNA-31 (miR-31) expression was measured. miR-31 expression was measured in colonoid cultures generated from controls and patients with CD. We performed small RNA-sequencing of formalin-fixed paraffin-embedded colon and ileum biopsies from treatment-naive pediatric patients with CD and controls and collected data on disease features and outcomes. RESULTS. Small RNA-sequencing and microRNA profiling in the colon revealed 2 distinct molecular subtypes, each with different clinical associations. Notably, we found that miR-31 expression was a driver of these 2 subtypes and, further, that miR-31 expression was particularly pronounced in epithelial cells. Colonoids revealed that miR-31 expression differences are preserved in this ex vivo system. In adult patients, low colonic miR-31 expression levels at the time of surgery were associated with worse disease outcome as measured by need for an end ileostomy and recurrence of disease in the neoterminal ileum. In pediatric patients, lower miR-31 expression at the time of diagnosis was associated with future development of fibrostenotic ileal CD requiring surgery CONCLUSIONS. These findings represent an important step forward in designing more effective clinical trials and developing personalized CD therapies. FUNDING. This work was supported by CCF Career Development Award (SZS), R01-ES024983 from NIEHS (SZS and TSF), 1R01DK104828-01A1 from NIDDK (SZS and TSF), P01-DK094779-01A1 from NIDDK (SZS), P30-DK034987 from NIDDK (SZS), 1-16-ACE-47 ADA Pathway Award (PS), UNC Nutrition Obesity Research Center Pilot & Feasibility Grant P30DK056350 (PS), CCF PRO-KIIDS NETWORK (SZS and PS), UNC CGIBD T32 Training Grant from NIDDK (JBB), T32 Training Grant (5T32GM007092-42) from NIGMS (MH), and SHARE from the Helmsley Trust (SZS). The UNC Translational Pathology Laboratory is supported, in part, by grants from the National Cancer Institute (3P30CA016086) and the UNC University Cancer Research Fund (UCRF) (PS).

The long-term efficacy of infliximab (IFX) for patients with refractory ulcerative colitis (UC) is unclear. The aim of this study was to assess the long-term outcomes of IFX treatment in patients with refractory UC.

Intestinal epithelial cell (IEC) barrier dysfunction is critical to the development of Crohn's disease (CD). However, the mechanism is understudied. We recently reported increased microRNA-31-5p (miR-31-5p) expression in colonic IECs of CD patients, but downstream targets and functional consequences are unknown. MiR-31-5p target genes were identified by integrative analysis of RNA- and small RNA-sequencing data from colonic mucosa and confirmed by qPCR in colonic IECs. Functional characterization of Activin Receptor-Like Kinase 1 (ACVRL1 or ALK1) in IECs was performed ex vivo using 2 dimensional-cultured human primary colonic IECs. The impact of altered colonic ALK1 signaling in CD for the risk of surgery and endoscopic relapse was evaluated by a multivariate regression analysis and a Kaplan-Meier estimator. ALK1 was identified as a target of miR-31-5p in colonic IECs of CD patients and confirmed using a 3'-UTR reporter assay. Activation of ALK1 restricted the proliferation of colonic IECs in an EdU proliferation assay and down-regulated the expression of stemness-related genes. Activated ALK1 signaling increased colonic IEC differentiation toward colonocytes. Down-regulated ALK1 signaling was associated with increased stemness and decreased colonocyte-specific marker expression in colonic IECs of CD patients compared to healthy controls. Activation of ALK1 enhanced epithelial barrier integrity in a trans-epithelial electrical resistance permeability assay. Lower colonic ALK1 expression was identified as an independent risk factor for surgery and associated with a higher risk of endoscopic relapse in CD patients. Decreased colonic ALK1 disrupted colonic IEC barrier integrity and associated with poor clinical outcomes in CD patients.

Early induction with biologics can reduce complications in patients with Crohn’s disease (CD) and improve their quality of life. The safety of biologics, however, is uncertain. Granulocyte and monocyte adsorptive apheresis (GMAA) is a natural biologic therapy that selectively removes granulocytes and monocytes/macrophages and has few severe adverse effects. The effects of GMAA on patients with early-diagnosed CD are unclear. We investigated the effects of GMAA combined with thiopurines on patients with early-diagnosed CD. Twenty-two corticosteroid- and biologic-naïve patients with active early-diagnosed CD were treated with intensive GMAA (twice per week) combined with thiopurines administration. Active early-diagnosed CD was defined as follows: (i) within 2years after diagnosis of CD, (ii) with no history of both surgical treatment and endoscopic dilation therapy, and (iii) Crohn’s Disease Activity Index (CDAI) was higher than 200. We investigated the ratios of clinical remission defined as CDAI was less than or equal to 150 at 2, 4, 6 and 52weeks and mucosal healing defined as a Simplified Endoscopic Activity Score for Crohn’s Disease (SES-CD) as 0 at 6 and 52weeks. Adverse events were recorded at each visit. The ratios of clinical remission at 2, 4, and 6 weeks were 6 of 22 (27.2%), 12 of 22 (54.5%), and 17 of 22 (77.2%), respectively. At 52 weeks, 18 of 21 patients (81.8%) were in clinical remission. The ratios of mucosal healing at 6 and 52 weeks were 5 of 22 (22.7%) and 11 of 22 (50%), respectively. The difference in the mucosal healing ratio was significant between 6 and 52 weeks (p = 0.044). No serious adverse effects were observed during this study. Combination therapy with intensive GMAA and thiopurines administration rapidly induced high remission in patients with active early-diagnosed CD without serious adverse effect. Mucosal healing was observed in 50.0% of enrolled patients. This combination therapy might be a rational option for patients with early-diagnosed CD.

Increasing number of patients with ulcerative colitis (UC) have received biologic treatment during the last decade. The association between endoscopic healing (EH) and biologic treatment failure remains understudied. Medical information of UC patients who started biologic treatment was retrospectively collected. EH was defined as Mayo endoscopic subscore of 0 or 1. Loss of response (LOR)-free drug continuation rate was compared between patients who achieved EH and those who did not using Kaplan–Meier estimator. Fifty-two patients received 53 biologic treatments and underwent follow-up colonoscopies within 2 years. Thirty-three patients achieved EH, all of which remained on the same treatment without LOR during the observational period. Twenty patients did not achieve EH, 8 of which ultimately discontinued the treatment due to LOR to biologic agents. Kaplan–Meier estimator found a significantly lower drug continuation rate in patients without EH (p < 0.001; log-rank test). A Cox regression analysis identified EH as an independent factor associated with a reduced risk of LOR-related biologic treatment failure irrespective of the types of biologic agents (Hazard Ratio = 0.0324, p < 0.001). EH within 2 years is associated with a reduced risk of LOR-related biologic treatment failure in patients with UC.