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Week Six: Infliximab Trough Levels are Associated with One Year Clinical Outcomes in Pediatric IBD Patients
FC. High FC levels at routine measurement justify careful disease monitoring and evaluation of current treatment.
AGA Abstracts
Su1979 MAYO ENDOSCOPIC SUBSCORE DOES NOT PREDICT DISEASE PHENOTYPE IN PEDIATRIC ULCERATIVE COLITIS PATIENTS Joshua D. Noe, Jose Cabrera, Bhaskar Gurram, Steven Werlin Ulcerative colitis (UC) is an autoimmune disorder characterized by chronic inflammation of the colon with myriad severity and extent. The Mayo endoscopic subscore (MES) has been created in order to describe the macroscopic severity of the disease. Adult studies have shown the MES is useful to predict both short-term and long-term outcomes. No pediatric studies correlating outcome and MES have been done. Aim: We hypothesize that (1) a higher MES will predict a higher rate of colectomy and (2) patients with a higher MES will be more likely to require immunomodulators or biologic therapy compared to patients that require sulfasalazine or 5-aminosalicylates (5ASA) to maintain remission. Methods: A 10 year retrospective chart review of all UC patients who had their diagnostic colonoscopy at the Children's Hospital of Wisconsin was performed. 3 blinded investigators reviewed the de-identified endoscopic photos of that original colonoscopy and performed MES. The following data was collected from diagnosis to 5 years post-diagnosis: Date of birth; date of diagnosis; whether a colectomy had been performed at or before 1 year post-diagnosis, and at or before 5 years post-diagnosis; use of 5-ASAs or sulfasalazine; use of immunomodulators; use of biologics; extent of gross colitis as defined as the most proximal portion of the colon involved or distance from the anal verge. Results: 213 patients were identified, of whom 171 had photographs available that could have MES performed confidently. 28 patients underwent colectomy. There was moderate agreement between the three observers calculating MES (Kappa coefficient ranged 0.42-0.59). Regardless of which investigator's MES was used, MES did not predict colectomy, including if a subject's highest MES score between observers was used (p=0.28). Secondarily regardless of which investigator's MES was used, or if a subject's highest MES score between observers was used, the MES did not distinguish between patients needing sulfasalazine or 5ASA (p=0.76) compared to those requiring immunomodulators (p=0.98) or those requiring biologic therapy (p=0.99). MES did not correlate with the extent of colitis proximal to the anus (p=0.61). Conclusion: In children with UC, the MES does not predict disease phenotype in pediatric patients, and it should not be used as a counseling measure when educating families.
FIgure 1. Distribution of active small bowel inflammation as determined by magnetic resonance enterography or wireless capsule endoscopy. Abbreviations: magnetic resonance enterography, MRE; wireless capsule endoscopy, WCE; terminal ileum, TI.
Figure 2. Terminal ileal inflammation as identified by ileo-colonoscopy, magnetic resonance enterography and wireless capsule endoscopy in 23 pediatric patients with suspected Crohn's disease. Abbreviations: magnetic resonance enterography, MRE; wireless capsule endoscopy, WCE.
Su1980 CAPSULE ENDOSCOPY COMPLEMENTS MAGNETIC RESONANCE ENTEROGRAPHY AND ILEO-COLONOSCOPY IN THE EVALUATION OF SUSPECTED SMALL BOWEL CROHN'S DISEASE IN PEDIATRIC PATIENTS David O. Prichard, Zachary Hamilton, Thomas Savage, Matthew Smyth, Carlie Penner, Alam Lakhani, Matthew Carroll, Ahmed A. Alsarkhy, Daniel Lemberg, Robert A. Enns, Robert J. Prosser, Daniel Jamieson, Kevan Jacobson
Su1981 CYTOMEGALOVIRUS INFECTION IN PEDIATRIC ACUTE SEVERE ULCERATIVE COLITIS - A MULTICENTER CASE-CONTROLLED STUDY FROM THE PEDIATRIC IBD PORTO GROUP OF ESPGHAN Shlomi Cohen, Christine Martinez-Vinson, Marina Aloi, Dan Turner, Amit Assa, Lissy de Ridder, Victorien Wolters, Tim de Meij, Patrizia Alvisi, Jiri Bronsky, Uri Kopylov
Background: Limited data exists regarding the relative ability of wireless capsule endoscopy (WCE) and magnetic resonance enterography (MRE) to identify mucosal inflammation in the small bowel (SB) of children with suspected Crohn's disease (CD). This study compares the ability of these modalities to identify SB inflammation in this cohort. In the terminal ileum (TI), these modalities are compared to the reference standard ileo-colonoscopy. Methods: Participants were prospectively recruited between 09/2010 and 12/2014. Inclusion criteria: children age 10-17 years requiring ileo-colonoscopy for evaluation of suspected CD. Exclusion criteria: ulcerative or infectious colitis, MRE contraindications (e.g. metal foreign body, severe renal insufficiency, contrast allergy or claustrophobia) or suspected high grade SB stricture. Subsequent to endoscopy, participants underwent MRE and WCE. Inflammation identified during ileocolonoscopy and WCE was scored using the Simple Endoscopic Score - Crohn's Disease (SES-CD) and the Lewis score respectively. Scores ≥ 1 and ≥135 respectively were considered active disease. For MRE, active inflammation in three defined SB segments (jejunum, proximal and distal ileum) was determined by the presence or absence of the following 5 variables: bowel wall thickening, bowel wall enhancement, fibro-fatty proliferation, hyperemia/vascular engorgement and proximal dilation. Each finding was given a score of 1 and a score ≥2 in any segment was considered active disease. Comparative analyses were performed using Cohen's kappa coefficient (κ), Spearman rank correlation (ρ) and bootstrap resampling techniques. Results: Of 35 recruited patients 23 completed the study protocol. Failure to complete the protocol was because of failure to swallow the capsule (n=7), failure to intubate the TI (n=3) or incomplete capsule studies (n=2). WCE and MRE were equally sensitive in identifying SB inflammation (17/23 [74%] vs. 15/23 [65%], P= NS). However, WCE detected more extensive SB disease relative to MRE with active disease throughout the SB in 13 [57%] vs. 1 [4%] patients (Figure 1). Within the TI, WCE identified numerically more patients with active mucosal inflammation than MRE or endoscopy (15 [65%] vs. 12 [52%] vs. 11 [48%] respectively, Figure 2). Bootstrapping techniques demonstrated that WCE is at least as sensitive as MRE or ileo-colonoscopy (both P=0.05) in identifying TI inflammation. The presence of ulcers on WCE correlated with bowel wall thickening and bowel wall enhancement on MRE (both κ=0.64, P=0.002) but not with fibro-fatty proliferation, hyperemia/vascular engorgement or proximal dilation. Conclusions: WCE is as sensitive as MRE or endoscopy for identifying active SB mucosal inflammation. In the absence of concern regarding stricturing or extra-luminal disease WCE can be considered for the evaluation of suspected SB CD.
Background: Data on the clinical course and outcomes of pediatric patients with cytomegalovirus (CMV) infection complicating acute severe ulcerative colitis (ASC) is very limited. The aim of our study was to compare the outcome of CMV-positive and negative pediatric ASC. Methods: This was a multicenter retrospective case-controlled study, from centers in Europe and Israel. We included CMV -positive pediatric patients hospitalized for acute severe colitis and compared their outcomes (rate of colectomy during hospitalization and up to 1 year from the hospitalization) to matched CMV-negative controls. Results: A total of 56 children from 10 centers were included. The patient cohort included 23 (41.1%) males/ 33 (58.9%) females, with a median age of 11.5 (interquartile range (IQR)- 7-14) years. Fifty-two (92.9%) of the patients had extensive/pan-colitis colitis and the rest left sided colitis, with severe disease in 52 (92.9%) of the patients and moderate in 4 (7.1%). Fifteen patients were CMVpositive and 41 - CMV-negative. Significantly higher proportion of CMV positive patients were resistant to intravenous corticosteroids (p=0.009). After diagnosis of CMV infection, 14/15 patients were started on gancyclovir (5 mg/kg- 5/14 (35.7%) and 10 mg/kg - 9/14 (64.3%). During hospitalization, 3 (20%) CMV positive and 3 (7.8%) CMV-negative patients required colectomy (p=0.17). By 12 months of follow-up,5 (33.3%) and 5 (12.5%) CMV positive and negative patients required colectomy, respectively (p=0.049). Previous antiTNF exposure and Pediatric Ulcerative Colitis Activity Index score on index date were significantly associated with the risk of colectomy during hospitalization and by 12 months( p=0.037 and p=0.01 for previous anti-TNF exposure and p=0.021 for PUCAI) on univariate analysis, however none of the factors including CMV positivity retained significance on multivariate analysis. Conclusions: A higher prevalence of CMV positivity was found in pediatric UC patients who required colectomy within 12 months of index hospitalisation, however the difference was not statistically significant on multivariate analysis. Further studies are merited to clarify the impact of CMV infection on the outcome of acute severe colitis in pediatric patients.
Su1982 WEEK SIX: INFLIXIMAB TROUGH LEVELS ARE ASSOCIATED WITH ONE YEAR CLINICAL OUTCOMES IN PEDIATRIC IBD PATIENTS Namita Singh, Yogesh Arora, Kelly Hester, Anjali Jain, Shervin Rabizadeh, Marla Dubinsky Background: Evidence suggests that week 14 infliximab (IFX) trough levels are associated with a durable response to IFX. It is unclear if there are markers that may be measured earlier than week 14 to predict long term outcomes of patients on IFX. We aim to determine
AGA Abstracts
S-618
Su1984 GIT1 PHOSPHORYLATION BY GRK2 REGULATES INTESTINAL EPITHELIAL RESTITUTION BY ALTERING RAC1 ACTIVITY AFTER WOUNDING Navneeta Rathor, Shelley R. Wang, Hee Kyoung Chung, Lan Xiao, James M. Donahue, Jian-Ying Wang, Rao N. Jaladanki The mammalian intestinal mucosa exhibits a spectrum of responses after acute injury and repairs itself rapidly to restore the epithelial integrity. Early epithelial restitution after superficial wounds is an important repair modality in the gut mucosa and occurs as a consequence of intestinal epithelial cell (IEC) migration rather than proliferation. Defected regulation of early mucosal restitution underlies various critical pathological states such as massive mucosal injury and hemorrhage. Our previous study shows that G-protein-coupled receptor (GPCR) kinase-interacting protein 1 (GIT1) is necessary for stimulation of IEC migration over the wounded area by activating Rac1, but the exact mechanism by which GIT1 is regulated remains unknown. GPCR kinase 2 (GRK2) is a key player in GPCR pathway and regulates many cellular processes by altering the activity of its downstream targets in response to stressful environments. This study determined if GRK2 modulates GIT1 activity after wounding, thus contributing the control of rapid epithelial restitution. Methods: Studies were conducted in differentiated IECs (IEC-Cdx2L1 line) induced by stable Cdx2-transfection. GIT1/GRK2 association was measured by immunoprecipitation assay. Functions of GRK2 were investigated by specific siRNA targeting GRK2 mRNA (siGRK2) or its specific chemical inhibitor. Cell migration was examined in an in vitro model that mimics early cell divisionindependent stages of epithelial restitution. Results: GRK2 directly interacted with GIT1 and formed [GRK2/GIT1] complex, and this association resulted in the phosphorylation of GIT1 and increased GIT1 activity. Migrating cells over the wounded area was associated with an increase in the levels of phosphorylated-GIT1 induced by GRK2. GRK2 silencing by transient transfection with siGRK2 decreased GIT1 phosphorylation and repressed its activity (by ~55%), although it failed to alter total cellular GIT1 level. Decreasing the levels of GRK2 by siGRK2 also decreased the levels of phosphorylated Rac1 and inhibited cell migration (by ~45%) after wounding. In GRK2-silenced population of cells, ectopically expressed Rac1 rescued cell migration after wounding. Similarly, treatment with the selective chemical inhibitor β-ARK1 specifically inhibited GRK2 activity, which was associated with a significant decrease in the levels of GRK2/GIT1 complex and phosphorylated-GIT1. The levels of phosphorylated GIT1 were decreased by ~45% in cells treated with β-ARK1. Inhibition of GIT1 activity by β-ARK1 also decreased the levels of phosphorylated Rac1 (by ~50%) and delayed epithelial restitution (by ~60%) after wounding. Conclusions: These results indicate that 1) GRK2 phosphorylates GIT1 and increases its activity and 2) GRK2mediated activation of GIT1 stimulates rapid epithelial restitution by enhancing Rac1 signaling.
Week 6 Infliximab Trough level by Week 54 persistent remission status
Su1983 Su1985 THE NOVEL TUMOR SUPPRESSIVE ROLE OF NOTCH1 IN COLITISASSOCIATED CANCER Pallavi Garg, Adani Pujada, Lewins Walter, Zhan Zhang, Hamed Laroui, Yuchen Zhang
GENE EXPRESSION PROFILES IN COLLAGENOUS COLITIS Qingqing Liu, Noam Harpaz
Introduction: Colitis-associated cancer (CAC) is chronic inflammation driven colon cancer, prevalent among individuals with inflammatory bowel disease. In CAC, p53 mutations are the first ones to be detected, followed by KRAS and APC mutations respectively. On the other hand in sporadic colon cancer (CRC) APC mutations are the first ones to be identified followed by KRAS and p53 mutations respectively. Therefore CAC is mechanistically different than CRC. Notch1 is a transmembrane protein. Notch1 signaling is important and well established for cell fate determination, stem cell potential,to and lineage commitment. Notch1 also contributes significantly to carcinogenesis. Notch1 is known to promote CRC. However, Notch1 function is highly context-dependent and, can be oncogenic or tumor suppressive. Aim: Aim of this study is to know the role of Notch1 in CAC in the setting of chronic inflammation. Methods: We used C57/B6 Notchflox/flox mice (control group) and crossed them with C57/B6 vilin-cre mice to generate Ncre mice (Notch1-/-), which cannot express Notch1 in villin-epithelium. CAC was induced by one injection of azoxymethane and two cycles of dextran sodium sulfate. We also used HCT116 cells overexpressing active Notch1 (Notch1 intracellular domain, NICD) to support our in vivo data. Results: Ncre mice had more body weight loss compared to controls in CAC. Colonoscopy indicated increased tumor burden and dysplastic lesions among Ncre mice versus controls. H&E staining indicated higher clinical score due to increased infiltration of inflammatory cells, extensive loss of crypt architecture and dysplasia. WB data showed increased PCNA expression (proliferation marker) while decreased expressions of cleaved caspase-3 (apoptotic marker). Ncre mice also exhibited high ROS levels and increased protein expression of γH2AX (DNA damage marker) compared to control in CAC. WB data showed a decrease in protein expressions of non-mutated (wild-type) p53 and p21 among Ncre mice versus control in CAC. We also observed altered levels of mismatch repair proteins MLH1 and MSH2 by WB among Ncre mice compared to controls in CAC. In vitro model of HCT116 overexpressing NICD displayed increased expressions of (wild-type) p53 and p21 but, decreased expression of γH2AX. Conclusion: Taken together our data suggest a novel tumor suppressive role of Notch1 in the colon in the setting of chronic inflammation. Our study implies that inhibition of Notch1 in colonic epithelium result in the accumulation of ROS levels leading to DNA damage due to lower levels of non-mutated p53 expression. Protective role of Notch1 in CAC suggests that the use of targeted Notch1 inhibitors should be avoided, specifically in CAC treatment.
BACKGROUND: Collagenous colitis (CC) is thought to result from dysregulated mucosal immune responses to unknown luminal agents in genetically susceptible individuals. Its association with immune dysregulation is suggested epidemiologically by its close associations with celiac disease and a variety of autoimmune disorders. We aimed to improve our understanding of its pathogenesis by means of gene expression profile analysis with a focus on inflammatory and immunological pathways. METHODS: Messenger RNA (mRNA) was isolated from colonic biopsies of 13 histologically confirmed CC and analyzed by the NanoString nCounter gene expression assay. The analysis included a comparison of mucosa with and without abnormal subepithelial collagen ("involved" and "uninvolved") (N=5), pooled biopsies of involved mucosa of additional patients (N=8) and pooled biopsies from control patients undergoing biopsies for unrelated reasons (N=8). Assays were carried out with 2 platforms targeting 594 and 184 genes differentially expressed in immunological and inflammatory conditions, respectively. The resulting raw expression data were normalized using nSolver Analysis Software 3.0 and a dataset of gene expression ratios for CC vs controls was generated. RESULTS: Compared to the non-CC controls, there was increased expression of matrix-matalloproteinases (MMP3, 7.84X; MMP9, 3.65X) in all cases of CC, confirming the results of a prior study. Expression of leukocyte immunoglobulin-like receptor subfamily B members (LILRBs), a group of critical negative regulators of inflammation and cytotoxicity, was increased 1.29-2.83X whereas LILRA3, a potential antagonist of LILRBs, was upregulated 27X. Additionally, there was increased expression of interferon gamma (31X) and its downstream genes (e.g., STAT1, 3.5X) as well as multiple T-lymphocyte chemokines (CXCLs, 5.07-13.39X) and their receptors (CXCRs, 2.79-5.71X). Expression of TGF-β1 and TNFα were only minimally increased (1.3X and 1.2X respectively). Importantly, each of these findings was observed in both involved and uninvolved mucosa of CC cases. CONCLUSION: The colonic mucosa in CC is characterized by enhanced expression of a limited repertoire of immunological and inflammatory genes. The fact that these alterations are expressed in histologically uninvolved as well as involved mucosa suggests that the underlying pathology is more globally distributed than its characteristically patchy histology.
Su1986 GUT LYMPHATIC PLASTICITY IN RESPONSE TO OBESITY AND INFLAMMATION Ya-Hsien Chou, Shih-Jung Peng, Pankaj J. Pasricha, Shiue-Cheng Tang Background. The intestinal lymphatic vessel network is responsible for lipid absorption and involves in inflammatory responses of intestinal diseases such as colitis. Despite the important roles of lymphatics in intestinal physiology and pathophysiology, the lymphatic vessel system in health and adaptation to diseases is understudied. This is largely due to the intricate and dispersed network of lymphatics which cannot be easily traced and characterized via standard microtome-based histology. Aims. To examine the response of the lymphatic system to obesity and inflammation in mouse models. Methods. We applied tissue clearing
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AGA Abstracts
AGA Abstracts
if IFX trough levels and C reactive protein (CRP) levels obtained at week 6 are associated with IFX outcomes at week 54. Methods: A prospective cohort of pediatric IBD patients initiating IFX therapy had blood drawn at each time point of IFX infusion starting at week 6, during the first year of IFX therapy. Blood was analyzed for IFX, anti-IFX antibodies and CRP levels. Outcome of week 54 persistent remission (PR) was defined as steroid- free clinical remission per the clinical disease activity index, without IFX dose intensification. Univariate analyses tested associations of week 6 IFX, week 14 IFX, baseline CRP, week 6 CRP, week 14 CRP and baseline immunomodulator use with week 54 outcomes. Results: 15 patients (7 with ulcerative colitis and 8 with Crohn's disease) were initiated on IFX therapy and were followed for 54 weeks. Median age of patients starting IFX was 14 years (range 8-22 years). Median week 6 IFX trough levels were higher in patients who were in week 54 PR than those that were not (23.5ug/ml in PR vs. 2.1ug/ml not in PR, p=0.03). Week 14 median IFX trough levels were higher in those in week 54 PR than those not in week 54 PR (10ug/ml in PR vs. 3.1ug/ml not in PR, p=0.03 ). IFX trough levels showed a positive trend between week 6 and week 14 (p=0.09). Median CRP level at week 6 was associated with week 54 PR (0.08 pg/ml in PR vs. 1.21 pg/ml not in PR, p=0.01). Baseline CRP level and concomitant immunomodulator (methotrexate, azathioprine, 6 mercaptopurine) use were not associated with week 54 PR. Conclusion: Lower week 6 CRP levels, higher week 6 IFX levels, and higher week 14 IFX levels were each independently associated with week 54 IFX efficacy. The utility of measuring IFX levels earlier than week 14 warrants further study, and has potential utility in early proactive infliximab dose optimization.
AGA Abstracts
Su1979 MAYO ENDOSCOPIC SUBSCORE DOES NOT PREDICT DISEASE PHENOTYPE IN PEDIATRIC ULCERATIVE COLITIS PATIENTS Joshua D. Noe, Jose Cabrera, Bhaskar Gurram, Steven Werlin Ulcerative colitis (UC) is an autoimmune disorder characterized by chronic inflammation of the colon with myriad severity and extent. The Mayo endoscopic subscore (MES) has been created in order to describe the macroscopic severity of the disease. Adult studies have shown the MES is useful to predict both short-term and long-term outcomes. No pediatric studies correlating outcome and MES have been done. Aim: We hypothesize that (1) a higher MES will predict a higher rate of colectomy and (2) patients with a higher MES will be more likely to require immunomodulators or biologic therapy compared to patients that require sulfasalazine or 5-aminosalicylates (5ASA) to maintain remission. Methods: A 10 year retrospective chart review of all UC patients who had their diagnostic colonoscopy at the Children's Hospital of Wisconsin was performed. 3 blinded investigators reviewed the de-identified endoscopic photos of that original colonoscopy and performed MES. The following data was collected from diagnosis to 5 years post-diagnosis: Date of birth; date of diagnosis; whether a colectomy had been performed at or before 1 year post-diagnosis, and at or before 5 years post-diagnosis; use of 5-ASAs or sulfasalazine; use of immunomodulators; use of biologics; extent of gross colitis as defined as the most proximal portion of the colon involved or distance from the anal verge. Results: 213 patients were identified, of whom 171 had photographs available that could have MES performed confidently. 28 patients underwent colectomy. There was moderate agreement between the three observers calculating MES (Kappa coefficient ranged 0.42-0.59). Regardless of which investigator's MES was used, MES did not predict colectomy, including if a subject's highest MES score between observers was used (p=0.28). Secondarily regardless of which investigator's MES was used, or if a subject's highest MES score between observers was used, the MES did not distinguish between patients needing sulfasalazine or 5ASA (p=0.76) compared to those requiring immunomodulators (p=0.98) or those requiring biologic therapy (p=0.99). MES did not correlate with the extent of colitis proximal to the anus (p=0.61). Conclusion: In children with UC, the MES does not predict disease phenotype in pediatric patients, and it should not be used as a counseling measure when educating families.
FIgure 1. Distribution of active small bowel inflammation as determined by magnetic resonance enterography or wireless capsule endoscopy. Abbreviations: magnetic resonance enterography, MRE; wireless capsule endoscopy, WCE; terminal ileum, TI.
Figure 2. Terminal ileal inflammation as identified by ileo-colonoscopy, magnetic resonance enterography and wireless capsule endoscopy in 23 pediatric patients with suspected Crohn's disease. Abbreviations: magnetic resonance enterography, MRE; wireless capsule endoscopy, WCE.
Su1980 CAPSULE ENDOSCOPY COMPLEMENTS MAGNETIC RESONANCE ENTEROGRAPHY AND ILEO-COLONOSCOPY IN THE EVALUATION OF SUSPECTED SMALL BOWEL CROHN'S DISEASE IN PEDIATRIC PATIENTS David O. Prichard, Zachary Hamilton, Thomas Savage, Matthew Smyth, Carlie Penner, Alam Lakhani, Matthew Carroll, Ahmed A. Alsarkhy, Daniel Lemberg, Robert A. Enns, Robert J. Prosser, Daniel Jamieson, Kevan Jacobson
Su1981 CYTOMEGALOVIRUS INFECTION IN PEDIATRIC ACUTE SEVERE ULCERATIVE COLITIS - A MULTICENTER CASE-CONTROLLED STUDY FROM THE PEDIATRIC IBD PORTO GROUP OF ESPGHAN Shlomi Cohen, Christine Martinez-Vinson, Marina Aloi, Dan Turner, Amit Assa, Lissy de Ridder, Victorien Wolters, Tim de Meij, Patrizia Alvisi, Jiri Bronsky, Uri Kopylov
Background: Limited data exists regarding the relative ability of wireless capsule endoscopy (WCE) and magnetic resonance enterography (MRE) to identify mucosal inflammation in the small bowel (SB) of children with suspected Crohn's disease (CD). This study compares the ability of these modalities to identify SB inflammation in this cohort. In the terminal ileum (TI), these modalities are compared to the reference standard ileo-colonoscopy. Methods: Participants were prospectively recruited between 09/2010 and 12/2014. Inclusion criteria: children age 10-17 years requiring ileo-colonoscopy for evaluation of suspected CD. Exclusion criteria: ulcerative or infectious colitis, MRE contraindications (e.g. metal foreign body, severe renal insufficiency, contrast allergy or claustrophobia) or suspected high grade SB stricture. Subsequent to endoscopy, participants underwent MRE and WCE. Inflammation identified during ileocolonoscopy and WCE was scored using the Simple Endoscopic Score - Crohn's Disease (SES-CD) and the Lewis score respectively. Scores ≥ 1 and ≥135 respectively were considered active disease. For MRE, active inflammation in three defined SB segments (jejunum, proximal and distal ileum) was determined by the presence or absence of the following 5 variables: bowel wall thickening, bowel wall enhancement, fibro-fatty proliferation, hyperemia/vascular engorgement and proximal dilation. Each finding was given a score of 1 and a score ≥2 in any segment was considered active disease. Comparative analyses were performed using Cohen's kappa coefficient (κ), Spearman rank correlation (ρ) and bootstrap resampling techniques. Results: Of 35 recruited patients 23 completed the study protocol. Failure to complete the protocol was because of failure to swallow the capsule (n=7), failure to intubate the TI (n=3) or incomplete capsule studies (n=2). WCE and MRE were equally sensitive in identifying SB inflammation (17/23 [74%] vs. 15/23 [65%], P= NS). However, WCE detected more extensive SB disease relative to MRE with active disease throughout the SB in 13 [57%] vs. 1 [4%] patients (Figure 1). Within the TI, WCE identified numerically more patients with active mucosal inflammation than MRE or endoscopy (15 [65%] vs. 12 [52%] vs. 11 [48%] respectively, Figure 2). Bootstrapping techniques demonstrated that WCE is at least as sensitive as MRE or ileo-colonoscopy (both P=0.05) in identifying TI inflammation. The presence of ulcers on WCE correlated with bowel wall thickening and bowel wall enhancement on MRE (both κ=0.64, P=0.002) but not with fibro-fatty proliferation, hyperemia/vascular engorgement or proximal dilation. Conclusions: WCE is as sensitive as MRE or endoscopy for identifying active SB mucosal inflammation. In the absence of concern regarding stricturing or extra-luminal disease WCE can be considered for the evaluation of suspected SB CD.
Background: Data on the clinical course and outcomes of pediatric patients with cytomegalovirus (CMV) infection complicating acute severe ulcerative colitis (ASC) is very limited. The aim of our study was to compare the outcome of CMV-positive and negative pediatric ASC. Methods: This was a multicenter retrospective case-controlled study, from centers in Europe and Israel. We included CMV -positive pediatric patients hospitalized for acute severe colitis and compared their outcomes (rate of colectomy during hospitalization and up to 1 year from the hospitalization) to matched CMV-negative controls. Results: A total of 56 children from 10 centers were included. The patient cohort included 23 (41.1%) males/ 33 (58.9%) females, with a median age of 11.5 (interquartile range (IQR)- 7-14) years. Fifty-two (92.9%) of the patients had extensive/pan-colitis colitis and the rest left sided colitis, with severe disease in 52 (92.9%) of the patients and moderate in 4 (7.1%). Fifteen patients were CMVpositive and 41 - CMV-negative. Significantly higher proportion of CMV positive patients were resistant to intravenous corticosteroids (p=0.009). After diagnosis of CMV infection, 14/15 patients were started on gancyclovir (5 mg/kg- 5/14 (35.7%) and 10 mg/kg - 9/14 (64.3%). During hospitalization, 3 (20%) CMV positive and 3 (7.8%) CMV-negative patients required colectomy (p=0.17). By 12 months of follow-up,5 (33.3%) and 5 (12.5%) CMV positive and negative patients required colectomy, respectively (p=0.049). Previous antiTNF exposure and Pediatric Ulcerative Colitis Activity Index score on index date were significantly associated with the risk of colectomy during hospitalization and by 12 months( p=0.037 and p=0.01 for previous anti-TNF exposure and p=0.021 for PUCAI) on univariate analysis, however none of the factors including CMV positivity retained significance on multivariate analysis. Conclusions: A higher prevalence of CMV positivity was found in pediatric UC patients who required colectomy within 12 months of index hospitalisation, however the difference was not statistically significant on multivariate analysis. Further studies are merited to clarify the impact of CMV infection on the outcome of acute severe colitis in pediatric patients.
Su1982 WEEK SIX: INFLIXIMAB TROUGH LEVELS ARE ASSOCIATED WITH ONE YEAR CLINICAL OUTCOMES IN PEDIATRIC IBD PATIENTS Namita Singh, Yogesh Arora, Kelly Hester, Anjali Jain, Shervin Rabizadeh, Marla Dubinsky Background: Evidence suggests that week 14 infliximab (IFX) trough levels are associated with a durable response to IFX. It is unclear if there are markers that may be measured earlier than week 14 to predict long term outcomes of patients on IFX. We aim to determine
AGA Abstracts
S-618
Su1984 GIT1 PHOSPHORYLATION BY GRK2 REGULATES INTESTINAL EPITHELIAL RESTITUTION BY ALTERING RAC1 ACTIVITY AFTER WOUNDING Navneeta Rathor, Shelley R. Wang, Hee Kyoung Chung, Lan Xiao, James M. Donahue, Jian-Ying Wang, Rao N. Jaladanki The mammalian intestinal mucosa exhibits a spectrum of responses after acute injury and repairs itself rapidly to restore the epithelial integrity. Early epithelial restitution after superficial wounds is an important repair modality in the gut mucosa and occurs as a consequence of intestinal epithelial cell (IEC) migration rather than proliferation. Defected regulation of early mucosal restitution underlies various critical pathological states such as massive mucosal injury and hemorrhage. Our previous study shows that G-protein-coupled receptor (GPCR) kinase-interacting protein 1 (GIT1) is necessary for stimulation of IEC migration over the wounded area by activating Rac1, but the exact mechanism by which GIT1 is regulated remains unknown. GPCR kinase 2 (GRK2) is a key player in GPCR pathway and regulates many cellular processes by altering the activity of its downstream targets in response to stressful environments. This study determined if GRK2 modulates GIT1 activity after wounding, thus contributing the control of rapid epithelial restitution. Methods: Studies were conducted in differentiated IECs (IEC-Cdx2L1 line) induced by stable Cdx2-transfection. GIT1/GRK2 association was measured by immunoprecipitation assay. Functions of GRK2 were investigated by specific siRNA targeting GRK2 mRNA (siGRK2) or its specific chemical inhibitor. Cell migration was examined in an in vitro model that mimics early cell divisionindependent stages of epithelial restitution. Results: GRK2 directly interacted with GIT1 and formed [GRK2/GIT1] complex, and this association resulted in the phosphorylation of GIT1 and increased GIT1 activity. Migrating cells over the wounded area was associated with an increase in the levels of phosphorylated-GIT1 induced by GRK2. GRK2 silencing by transient transfection with siGRK2 decreased GIT1 phosphorylation and repressed its activity (by ~55%), although it failed to alter total cellular GIT1 level. Decreasing the levels of GRK2 by siGRK2 also decreased the levels of phosphorylated Rac1 and inhibited cell migration (by ~45%) after wounding. In GRK2-silenced population of cells, ectopically expressed Rac1 rescued cell migration after wounding. Similarly, treatment with the selective chemical inhibitor β-ARK1 specifically inhibited GRK2 activity, which was associated with a significant decrease in the levels of GRK2/GIT1 complex and phosphorylated-GIT1. The levels of phosphorylated GIT1 were decreased by ~45% in cells treated with β-ARK1. Inhibition of GIT1 activity by β-ARK1 also decreased the levels of phosphorylated Rac1 (by ~50%) and delayed epithelial restitution (by ~60%) after wounding. Conclusions: These results indicate that 1) GRK2 phosphorylates GIT1 and increases its activity and 2) GRK2mediated activation of GIT1 stimulates rapid epithelial restitution by enhancing Rac1 signaling.
Week 6 Infliximab Trough level by Week 54 persistent remission status
Su1983 Su1985 THE NOVEL TUMOR SUPPRESSIVE ROLE OF NOTCH1 IN COLITISASSOCIATED CANCER Pallavi Garg, Adani Pujada, Lewins Walter, Zhan Zhang, Hamed Laroui, Yuchen Zhang
GENE EXPRESSION PROFILES IN COLLAGENOUS COLITIS Qingqing Liu, Noam Harpaz
Introduction: Colitis-associated cancer (CAC) is chronic inflammation driven colon cancer, prevalent among individuals with inflammatory bowel disease. In CAC, p53 mutations are the first ones to be detected, followed by KRAS and APC mutations respectively. On the other hand in sporadic colon cancer (CRC) APC mutations are the first ones to be identified followed by KRAS and p53 mutations respectively. Therefore CAC is mechanistically different than CRC. Notch1 is a transmembrane protein. Notch1 signaling is important and well established for cell fate determination, stem cell potential,to and lineage commitment. Notch1 also contributes significantly to carcinogenesis. Notch1 is known to promote CRC. However, Notch1 function is highly context-dependent and, can be oncogenic or tumor suppressive. Aim: Aim of this study is to know the role of Notch1 in CAC in the setting of chronic inflammation. Methods: We used C57/B6 Notchflox/flox mice (control group) and crossed them with C57/B6 vilin-cre mice to generate Ncre mice (Notch1-/-), which cannot express Notch1 in villin-epithelium. CAC was induced by one injection of azoxymethane and two cycles of dextran sodium sulfate. We also used HCT116 cells overexpressing active Notch1 (Notch1 intracellular domain, NICD) to support our in vivo data. Results: Ncre mice had more body weight loss compared to controls in CAC. Colonoscopy indicated increased tumor burden and dysplastic lesions among Ncre mice versus controls. H&E staining indicated higher clinical score due to increased infiltration of inflammatory cells, extensive loss of crypt architecture and dysplasia. WB data showed increased PCNA expression (proliferation marker) while decreased expressions of cleaved caspase-3 (apoptotic marker). Ncre mice also exhibited high ROS levels and increased protein expression of γH2AX (DNA damage marker) compared to control in CAC. WB data showed a decrease in protein expressions of non-mutated (wild-type) p53 and p21 among Ncre mice versus control in CAC. We also observed altered levels of mismatch repair proteins MLH1 and MSH2 by WB among Ncre mice compared to controls in CAC. In vitro model of HCT116 overexpressing NICD displayed increased expressions of (wild-type) p53 and p21 but, decreased expression of γH2AX. Conclusion: Taken together our data suggest a novel tumor suppressive role of Notch1 in the colon in the setting of chronic inflammation. Our study implies that inhibition of Notch1 in colonic epithelium result in the accumulation of ROS levels leading to DNA damage due to lower levels of non-mutated p53 expression. Protective role of Notch1 in CAC suggests that the use of targeted Notch1 inhibitors should be avoided, specifically in CAC treatment.
BACKGROUND: Collagenous colitis (CC) is thought to result from dysregulated mucosal immune responses to unknown luminal agents in genetically susceptible individuals. Its association with immune dysregulation is suggested epidemiologically by its close associations with celiac disease and a variety of autoimmune disorders. We aimed to improve our understanding of its pathogenesis by means of gene expression profile analysis with a focus on inflammatory and immunological pathways. METHODS: Messenger RNA (mRNA) was isolated from colonic biopsies of 13 histologically confirmed CC and analyzed by the NanoString nCounter gene expression assay. The analysis included a comparison of mucosa with and without abnormal subepithelial collagen ("involved" and "uninvolved") (N=5), pooled biopsies of involved mucosa of additional patients (N=8) and pooled biopsies from control patients undergoing biopsies for unrelated reasons (N=8). Assays were carried out with 2 platforms targeting 594 and 184 genes differentially expressed in immunological and inflammatory conditions, respectively. The resulting raw expression data were normalized using nSolver Analysis Software 3.0 and a dataset of gene expression ratios for CC vs controls was generated. RESULTS: Compared to the non-CC controls, there was increased expression of matrix-matalloproteinases (MMP3, 7.84X; MMP9, 3.65X) in all cases of CC, confirming the results of a prior study. Expression of leukocyte immunoglobulin-like receptor subfamily B members (LILRBs), a group of critical negative regulators of inflammation and cytotoxicity, was increased 1.29-2.83X whereas LILRA3, a potential antagonist of LILRBs, was upregulated 27X. Additionally, there was increased expression of interferon gamma (31X) and its downstream genes (e.g., STAT1, 3.5X) as well as multiple T-lymphocyte chemokines (CXCLs, 5.07-13.39X) and their receptors (CXCRs, 2.79-5.71X). Expression of TGF-β1 and TNFα were only minimally increased (1.3X and 1.2X respectively). Importantly, each of these findings was observed in both involved and uninvolved mucosa of CC cases. CONCLUSION: The colonic mucosa in CC is characterized by enhanced expression of a limited repertoire of immunological and inflammatory genes. The fact that these alterations are expressed in histologically uninvolved as well as involved mucosa suggests that the underlying pathology is more globally distributed than its characteristically patchy histology.
Su1986 GUT LYMPHATIC PLASTICITY IN RESPONSE TO OBESITY AND INFLAMMATION Ya-Hsien Chou, Shih-Jung Peng, Pankaj J. Pasricha, Shiue-Cheng Tang Background. The intestinal lymphatic vessel network is responsible for lipid absorption and involves in inflammatory responses of intestinal diseases such as colitis. Despite the important roles of lymphatics in intestinal physiology and pathophysiology, the lymphatic vessel system in health and adaptation to diseases is understudied. This is largely due to the intricate and dispersed network of lymphatics which cannot be easily traced and characterized via standard microtome-based histology. Aims. To examine the response of the lymphatic system to obesity and inflammation in mouse models. Methods. We applied tissue clearing
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AGA Abstracts
AGA Abstracts
if IFX trough levels and C reactive protein (CRP) levels obtained at week 6 are associated with IFX outcomes at week 54. Methods: A prospective cohort of pediatric IBD patients initiating IFX therapy had blood drawn at each time point of IFX infusion starting at week 6, during the first year of IFX therapy. Blood was analyzed for IFX, anti-IFX antibodies and CRP levels. Outcome of week 54 persistent remission (PR) was defined as steroid- free clinical remission per the clinical disease activity index, without IFX dose intensification. Univariate analyses tested associations of week 6 IFX, week 14 IFX, baseline CRP, week 6 CRP, week 14 CRP and baseline immunomodulator use with week 54 outcomes. Results: 15 patients (7 with ulcerative colitis and 8 with Crohn's disease) were initiated on IFX therapy and were followed for 54 weeks. Median age of patients starting IFX was 14 years (range 8-22 years). Median week 6 IFX trough levels were higher in patients who were in week 54 PR than those that were not (23.5ug/ml in PR vs. 2.1ug/ml not in PR, p=0.03). Week 14 median IFX trough levels were higher in those in week 54 PR than those not in week 54 PR (10ug/ml in PR vs. 3.1ug/ml not in PR, p=0.03 ). IFX trough levels showed a positive trend between week 6 and week 14 (p=0.09). Median CRP level at week 6 was associated with week 54 PR (0.08 pg/ml in PR vs. 1.21 pg/ml not in PR, p=0.01). Baseline CRP level and concomitant immunomodulator (methotrexate, azathioprine, 6 mercaptopurine) use were not associated with week 54 PR. Conclusion: Lower week 6 CRP levels, higher week 6 IFX levels, and higher week 14 IFX levels were each independently associated with week 54 IFX efficacy. The utility of measuring IFX levels earlier than week 14 warrants further study, and has potential utility in early proactive infliximab dose optimization.