Stratification of risk of progression to colectomy in ulcerative colitis via measured and predicted gene expression.

An important goal of clinical genomics is to be able to estimate the risk of adverse disease outcomes. Between 5% and 10% of individuals with ulcerative colitis (UC) require colectomy within 5 years of diagnosis, but polygenic risk scores (PRSs) utilizing findings from genome-wide association studies (GWASs) are unable to provide meaningful prediction of this adverse status. By contrast, in Crohn disease, gene expression profiling of GWAS-significant genes does provide some stratification of risk of progression to complicated disease in the form of a transcriptional risk score (TRS). Here, we demonstrate that a measured TRS based on bulk rectal gene expression in the PROTECT inception cohort study has a positive predictive value approaching 50% for colectomy. Single-cell profiling demonstrates that the genes are active in multiple diverse cell types from both the epithelial and immune compartments. Expression quantitative trait locus (QTL) analysis identifies genes with differential effects at baseline and week 52 follow-up, but for the most part, differential expression associated with colectomy risk is independent of local genetic regulation. Nevertheless, a predicted polygenic transcriptional risk score (PPTRS) derived by summation of transcriptome-wide association study (TWAS) effects identifies UC-affected individuals at 5-fold elevated risk of colectomy with data from the UK Biobank population cohort studies, independently replicated in an NIDDK-IBDGC dataset. Prediction of gene expression from relatively small transcriptome datasets can thus be used in conjunction with TWASs for stratification of risk of disease complications.

Baseline Clinical Factors Are Associated With Risk of Complications in Crohn's Disease: Appraisal of the American Gastroenterological Association Clinical Care Pathway.

INTRODUCTION: The American Gastroenterological Association (AGA) has compiled risk factors that may be predictive of disease complications in Crohn's disease (CD) and ulcerative colitis (UC). The aim of this study was to evaluate the performance of the AGA risk factors for risk stratification in UC and CD. METHODS: We included participants of 2 cohorts: the Ocean State Crohn's and Colitis Area Registry cohort and the Mayo Clinic cohort. Baseline clinical risk factors were extracted according to the AGA pathway. Our primary end point was defined as follows: (i) any inflammatory bowel disease related-hospitalization, (ii) any inflammatory bowel disease-related bowel surgery, or (iii) any progression of disease. We analyzed the association of the number of AGA risk factors with our end point. Statistical multivariable modeling was performed with Cox proportional hazards model. RESULTS: A total of 412 patients with CD were included. Comparing ≥3 risk factors with 0-1 risk factor, we found a significantly increased risk of complications in both the Ocean State Crohn's and Colitis Area Registry cohort (hazard ratio [HR] 2.75, 95% confidence interval 1.71-4.41) and Mayo Clinic cohort (HR 2.07, 95% confidence interval 1.11-3.84). Diagnosis at younger age (HR 2.07), perianal disease (HR 1.99), and B2/B3 behavior (HR 1.92) were significantly associated with disease complications. We did not observe a consistent association between number of risk factors nor any specific individual risk factors and risk of disease complications in the 265 patients with UC included. DISCUSSION: We found a significant association between the number of AGA risk factors and the risk of disease complication in CD; this association was not significant in UC. The presence of ≥ 3 risk factors in CD leads to the highest risk of complications. The AGA care pathway is a useful tool to stratify patients who are at higher risk of disease complications in patients with CD.

Safety and Durability of Accelerated Infliximab Dosing Strategies in Pediatric IBD: A Single Center, Retrospective Study.

OBJECTIVES: Infliximab (IFX) is commonly used to treat children with inflammatory bowel disease (IBD). We previously reported that patients with extensive disease started on IFX at a dose of 10 mg/kg had greater treatment durability at year one. The aim of this follow-up study is to assess the long-term safety and durability of this dosing strategy in pediatric IBD. METHODS: We performed a retrospective single-center study of pediatric IBD patients started on IFX over a 10-year period. RESULTS: Two hundred ninety-one patients were included (mean age = 12.61, 38% female) with a follow-up range of 0.1-9.7 years from IFX induction. One hundred fifty-five (53%) were started at a dose of 10 mg/kg. Only 35 patients (12%) discontinued IFX. The median duration of treatment was 2.9 years. Patients with ulcerative colitis ( P ≤ 0.01) and patients with extensive disease ( P = 0.01) had lower durability, despite a higher starting dose of IFX ( P = 0.03). Adverse events (AEs) were observed to occur at a rate of 234 per 1000 patient-years. Patients with a higher serum IFX trough level (≥20 µg/mL) had a higher rate of AEs ( P = 0.01). Use of combination therapy had no impact on risk of AEs ( P = 0.78). CONCLUSIONS: We observed an excellent IFX treatment durability, with only 12% of patients discontinuing therapy over the observed timeframe. The overall rate of AEs was low, the majority being infusion reactions and dermatologic conditions. Higher IFX dose and serum trough level> 20 µg/mL were associated with higher risk of AEs, the majority being mild and not resulting in cessation of therapy.

Emulsifiers and Intestinal Health: An Introduction.

ABSTRACT: Food additives in general, and emulsifiers in particular, are considered to be important dietary components with a potential to harm the intestine, in part by promoting intestinal inflammation. There is inadequate objective information about the specific nature and the magnitude of the problem.The Food and Drug Administration (FDA) has recognized approximately 450 items added to our foods as being generally regarded as safe and has placed them on a generally regarded as safe (GRAS) list. Additionally, it has also approved approximately 3000 "food additives." There is a general lack of transparency as to how either of these selections were and continue to be made. Once items are officially designated by the FDA as "food additives" or placed on the GRAS list, there is no regulatory mechanism for the ongoing monitoring of their safety.The most widely used emulsifier is "lecithin," which is biochemically identified as phosphatidylcholine (PC). Regulatory guidelines allow manufacturers to use the label "lecithin" to be applied to emulsifiers that contain PC plus other phospholipids in a variety of unspecified concentrations. The PC used in experiments cited in the literature, is unlikely to be the same thing as the "lecithin" in our diets.The objective of this introduction to emulsifiers is to raise awareness of the current state of food additives in the USA and to encourage thoughtful approaches to the study of all additives found in our diets. The overriding goal should be to assure the safety of what we eat. As examples we discuss eight widely distributed food additives; four "natural" emulsifiers that are classified as GRAS as well as an additional emulsifier-associated food additive that is also on the GRAS list, and three synthetic emulsifying agents that are FDA approved as "food additives."

Early Change in Fecal Calprotectin Predicts One-Year Outcome in Children Newly Diagnosed With Ulcerative Colitis.

INTRODUCTION: While fecal calprotectin (FC) is used to assess disease activity in ulcerative colitis (UC) there are little data concerning the role of serial FC levels at diagnosis in predicting clinical course. We sought to determine whether FC at diagnosis or early change following therapy predicts clinical outcomes in pediatric UC.Methods: Children with newly diagnosed UC were treated with standardized regimens of mesalamine or corticosteroids (CS). CS tapering and escalation to additional therapy or colectomy were by protocol. Patients with baseline or week 4 or week 12 FC levels were included in the analysis. Our primary outcome was CS-free remission on mesalamine at week 52. We compared the prognostic value of a baseline FC as well as a change in FC by week 4 or week 12 in predicting clinical outcomes. RESULTS: The study included 352 children (113 initial mesalamine, 239 initial CS, mean age 12.6 years) with UC. At Week 52, 135 (38.3%), 84 (23.8%), and 19 (5.4%) children achieved CS-free remission, needed anti-tumor necrosis factor therapy or had colectomy respectively. Baseline FC was not associated with CS-free remission at week 52. However, both week 4 (odds ratio [OR] 0.95, 95% confidence interval [CI] 0.901.00) and week 12 FC levels (OR 0.91, 95% CI 0.87-0.96) were associated with outcomes, with the latter having a stronger association with CS-free remission. Patients with a >75% decrease by 12 weeks, had a 3-fold increased likelihood of CS-free remission at 1 year. DISCUSSION: Longitudinal changes in FC may predict 1 year outcomes better than values at diagnosis in children with a new diagnosis of UC.

Clinical and biological predictors of response to standardised paediatric colitis therapy (PROTECT): a multicentre inception cohort study.

BACKGROUND: Lack of evidence-based outcomes data leads to uncertainty in developing treatment regimens in children who are newly diagnosed with ulcerative colitis. We hypothesised that pretreatment clinical, transcriptomic, and microbial factors predict disease course. METHODS: In this inception cohort study, we recruited paediatric patients aged 4-17 years with newly diagnosed ulcerative colitis from 29 centres in the USA and Canada. Patients initially received standardised mesalazine or corticosteroids, with pre-established criteria for escalation to immunomodulators (ie, thiopurines) or anti-tumor necrosis factor-α (TNFα) therapy. We used RNA sequencing to define rectal gene expression before treatment, and 16S sequencing to characterise rectal and faecal microbiota. The primary outcome was week 52 corticosteroid-free remission with no therapy beyond mesalazine. We assessed factors associated with the primary outcome using logistic regression models of the per-protocol population. This study is registered with ClinicalTrials.gov, number NCT01536535. FINDINGS: Between July 10, 2012, and April 21, 2015, of 467 patients recruited, 428 started medical therapy, of whom 400 (93%) were evaluable at 52 weeks and 386 (90%) completed the study period with no protocol violations. 150 (38%) of 400 participants achieved week 52 corticosteroid-free remission, of whom 147 (98%) were taking mesalazine and three (2%) were taking no medication. 74 (19%) of 400 were escalated to immunomodulators alone, 123 (31%) anti-TNFα therapy, and 25 (6%) colectomy. Low baseline clinical severity, high baseline haemoglobin, and week 4 clinical remission were associated with achieving week 52 corticosteroid-free remission (n=386, logistic model area under the curve [AUC] 0·70, 95% CI 0·65-0·75; specificity 77%, 95% CI 71-82). Baseline severity and remission by week 4 were validated in an independent cohort of 274 paediatric patients with newly diagnosed ulcerative colitis. After adjusting for clinical predictors, an antimicrobial peptide gene signature (odds ratio [OR] 0·57, 95% CI 0·39-0·81; p=0·002) and abundance of Ruminococcaceae (OR 1·43, 1·02-2·00; p=0·04), and Sutterella (OR 0·81, 0·65-1·00; p=0·05) were independently associated with week 52 corticosteroid-free remission. INTERPRETATION: Our findings support the utility of initial clinical activity and treatment response by 4 weeks to predict week 52 corticosteroid-free remission with mesalazine alone in children who are newly diagnosed with ulcerative colitis. The development of personalised clinical and biological signatures holds the promise of informing ulcerative colitis therapeutic decisions. FUNDING: US National Institutes of Health.

Harmonizing Nutritional Therapies for Pediatric Inflammatory Bowel Disease.

Uses of nutritional therapies for inflammatory bowel disease (IBD) are of tremendous interest to the lay and professional communities. This interest currently outweighs the scientific basis for deciding on a particular therapy for any given patient. Some nutritional therapies have credible reports, in peer-review journals, validating their use for some patients. The broad pediatric gastroenterology community in the United States has, however, been unable or unwilling to agree on the details necessary to disseminate the most effective therapies with adequate reliability and validity to implement these interventions successfully. The well-established importance of the appropriate use of nutritional interventions for the treatment of undernutrition and maintenance of optimal nutrition is not an issue. A consensus and widely applicable solution for nutrition as therapy for IBD is, however, not imminent. In the interim, we aim to help the science-based reader to evaluate manuscripts appearing in our journals and to use this information to make rational, informed therapeutic decisions. We outline the current limited evidence base and make recommendations to advance the field of nutritional therapy in IBD.

Constipation.

Constipation in otherwise healthy infants and children is a common problem despite confusion about how to precisely define constipation and constipation-related disorders. Constipation may, rarely, be a sign or symptom of a more serious disease or a diagnosis defined only by its symptoms and without any structural or biochemical findings. In the latter case it is classified as a functional gastrointestinal disorder (FGID). FGIDs are defined as disorders that cannot be explained by structural or biochemical findings. The Rome Foundation has standardized diagnostic criteria for all FGIDs. The Rome criteria are based on the available research as well as the clinical experience of the Foundation's assembled experts. The most recent report, Rome IV, described clinical criteria and diagnostic tools and encouraged more rigorous research in the area of FGIDs. The true incidence and prevalence of constipation is difficult to know because it may be treated at home using home remedies or diagnosed at a visit to a primary care provider or to a subspecialist pediatric gastroenterologist. The most recent attempts to define the prevalence of all pediatric FGIDs have been made using the Rome IV criteria. The defined FGID entities that may be associated with the complaint of constipation are infant dyschezia, functional constipation, and nonretentive fecal incontinence. The term encopresis, omitted from Rome IV, is defined by the American Psychiatric Association (APA) in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition The 3 Rome-defined (constipation-related) entities and the APA entity of encopresis are the focus of this review.

Clinical and Genomic Correlates of Neutrophil Reactive Oxygen Species Production in Pediatric Patients With Crohn's Disease.

BACKGROUND & AIMS: Individuals with monogenic disorders of phagocyte function develop chronic colitis that resembles Crohn's disease (CD). We tested for associations between mutations in genes encoding reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, neutrophil function, and phenotypes of CD in pediatric patients. METHODS: We performed whole-exome sequence analysis to identify mutations in genes encoding NADPH oxidases (such as CYBA, CYBB, NCF1, NCF2, NCF4, RAC1, and RAC2) using DNA from 543 pediatric patients with inflammatory bowel diseases. Blood samples were collected from an additional 129 pediatric patients with CD and 26 children without IBD (controls); we performed assays for neutrophil activation, reactive oxygen species (ROS) production, and bacteria uptake and killing. Whole-exome sequence analysis was performed using DNA from 46 of the children with CD to examine associations with NADPH gene mutations; RNA sequence analyses were performed using blood cells from 46 children with CD to test for variations in neutrophil gene expression associated with ROS production. RESULTS: We identified 26 missense mutations in CYBA, CYBB, NCF1, NCF2, and NCF4. Patients with CD who carried mutations in these genes were 3-fold more likely to have perianal disease (P = .0008) and stricturing complications (P = .002) than children with CD without these mutations. Among patients with CD with none of these mutations, 9% had undergone abdominal surgery; among patients with mutations in these NADPH oxidase genes, 31% had undergone abdominal surgery (P = .0004). A higher proportion of neutrophils from children with CD had low ROS production (47%) than from controls (15%) among the 129 patients tested for ROS (P = .002). Minor alleles of the NADPH genes were detected in 7% of children with CD whose neutrophils produced normal levels of ROS vs 38% of children whose neutrophils produced low levels of ROS (P = .009). Neutrophils that produced low levels of ROS had specific alterations in genes that regulate glucose metabolism and antimicrobial responses. CONCLUSIONS: We identified missense mutations in genes that encode NADPH oxidases in children with CD; these were associated with a more aggressive disease course and reduced ROS production by neutrophils from the patients.

Mucosal Expression of Type 2 and Type 17 Immune Response Genes Distinguishes Ulcerative Colitis From Colon-Only Crohn's Disease in Treatment-Naive Pediatric Patients.

BACKGROUND & AIMS: There is controversy regarding the role of the type 2 immune response in the pathogenesis of ulcerative colitis (UC)-few data are available from treatment-naive patients. We investigated whether genes associated with a type 2 immune response in the intestinal mucosa are up-regulated in treatment-naive pediatric patients with UC compared with patients with Crohn's disease (CD)-associated colitis or without inflammatory bowel disease (IBD), and whether expression levels are associated with clinical outcomes. METHODS: We used a real-time reverse-transcription quantitative polymerase chain reaction array to analyze messenger RNA (mRNA) expression patterns in rectal mucosal samples from 138 treatment-naive pediatric patients with IBD and macroscopic rectal disease, as well as those from 49 children without IBD (controls), enrolled in a multicenter prospective observational study from 2008 to 2012. Results were validated in real-time reverse-transcription quantitative polymerase chain reaction analyses of rectal RNA from an independent cohort of 34 pediatric patients with IBD and macroscopic rectal disease and 17 controls from Cincinnati Children's Hospital Medical Center. RESULTS: We measured significant increases in mRNAs associated with a type 2 immune response (interleukin [IL]5 gene, IL13, and IL13RA2) and a type 17 immune response (IL17A and IL23) in mucosal samples from patients with UC compared with patients with colon-only CD. In a regression model, increased expression of IL5 and IL17A mRNAs distinguished patients with UC from patients with colon-only CD (P = .001; area under the receiver operating characteristic curve, 0.72). We identified a gene expression pattern in rectal tissues of patients with UC, characterized by detection of IL13 mRNA, that predicted clinical response to therapy after 6 months (odds ratio [OR], 6.469; 95% confidence interval [CI], 1.553-26.94), clinical response after 12 months (OR, 6.125; 95% CI, 1.330-28.22), and remission after 12 months (OR, 5.333; 95% CI, 1.132-25.12). CONCLUSIONS: In an analysis of rectal tissues from treatment-naive pediatric patients with IBD, we observed activation of a type 2 immune response during the early course of UC. We were able to distinguish patients with UC from those with colon-only CD based on increased mucosal expression of genes that mediate type 2 and type 17 immune responses. Increased expression at diagnosis of genes that mediate a type 2 immune response is associated with response to therapy and remission in pediatric patients with UC.

Biologics Delay Progression of Crohn's Disease, but Not Early Surgery, in Children.

BACKGROUND & AIMS: Up to 30% of patients with Crohn's disease (CD) require surgery within the first 5 years from diagnosis. We investigated the recent risk of bowel surgery in an inception cohort of pediatric patients with CD and whether early use of biologics (tumor necrosis factor antagonists) alters later disease course. METHODS: We collected data from the Pediatric Inflammatory Bowel Disease Collaborative Research Group registry on 1442 children (age, ≤16 y) diagnosed with CD from January 2002 through December 2014. Data were collected at diagnosis, 30 days following diagnosis, and then quarterly and during hospitalizations for up to 12 years. Our primary aim was to determine the 10-year risk for surgery in children with CD. Our secondary aim was to determine whether early use of biologics (<3 mo of diagnosis) affected risk of disease progression. RESULTS: The 10-year risk of first bowel surgery was 26%. The 5-year risk of bowel surgery did not change from 2002 through 2014, and remained between 13% and 14%. Most surgeries occurred within 3 years from diagnosis. The only predictor of surgery was disease behavior at diagnosis. CD with inflammatory behavior had the lowest risk of surgery compared to stricturing disease, penetrating disease, or both. We associated slowing of disease progression to stricturing or penetrating disease (but not surgery) with early use of biologics, but this effect only became evident after 5 years of disease. Our results indicate that biologics slow disease progression over time (hazard ratio, 0.85; 95% CI, 0.76-0.95). CONCLUSIONS: In an analysis of data from a registry of pediatric patients with CD, we found that among those with significant and progressing disease at or shortly after presentation, early surgery is difficult to prevent, even with early use of biologics. Early use of biologics (<3 mo of diagnosis) can delay later disease progression to stricturing and/or penetrating disease, but this affect could become evident only years after initial management decisions are made.

Omes of Inflammatory Bowel Disease: A Primer for Clinicians.

Recent advances in high-throughput laboratory technologies and bioinformatics tools are redefining how we view inflammatory bowel disease (IBD). Instead of 2 diseases, we now see a diverse set of molecular subtypes. Large-scale investigation of the genome, exome, transcriptome, proteome, metabolome, microbiome, and epigenome are providing transformative insights into the pathophysiology of IBD, with the promise of accurately predicting prognosis and targeting therapy. Understanding these tools and their application is crucial to navigating the molecular era of IBD. This review aims to help the IBD clinician understand, appreciate, and eventually incorporate this coming paradigm shift to improve the care of children with IBD.

CHD6 regulates the topological arrangement of the CFTR locus.

The control of transcription is regulated through the well-coordinated spatial and temporal interactions between distal genomic regulatory elements required for specialized cell-type and developmental gene expression programs. With recent findings CFTR has served as a model to understand the principles that govern genome-wide and topological organization of distal intra-chromosomal contacts as it relates to transcriptional control. This is due to the extensive characterization of the DNase hypersensitivity sites, modification of chromatin, transcription factor binding sites and the arrangement of these sites in CFTR consistent with the restrictive expression in epithelial cell types. Here, we identified CHD6 from a screen among several chromatin-remodeling proteins as a putative epigenetic modulator of CFTR expression. Moreover, our findings of CTCF interactions with CHD6 are consistent with the role described previously for CTCF in CFTR regulation. Our results now reveal that the CHD6 protein lies within the infrastructure of multiple transcriptional complexes, such as the FACT, PBAF, PAF1C, Mediator, SMC/Cohesion and MLL complexes. This model underlies the fundamental role CHD6 facilitates by tethering cis-acting regulatory elements of CFTR in proximity to these multi-subunit transcriptional protein complexes. Finally, we indicate that CHD6 structurally coordinates a three-dimensional stricture between intragenic elements of CFTR bound by several cell-type specific transcription factors, such as CDX2, SOX18, HNF4α and HNF1α. Therefore, our results reveal new insights into the epigenetic regulation of CFTR expression, whereas the manipulation of CFTR gene topology could be considered for treating specific indications of cystic fibrosis and/or pancreatitis.

Durability of Infliximab Is Associated With Disease Extent in Children With Inflammatory Bowel Disease.

OBJECTIVES: The aim of the study was to evaluate infliximab (IFX) dosing and treatment durability relative to luminal disease burden in patients with inflammatory bowel disease. METHODS: Records from 98 pediatric patients treated with IFX between 2012 and 2014 were reviewed. Disease extent was classified as "limited," "moderate," or "extensive" based on cumulative assessment of mucosal involvement. Patients started taking standard 5 mg/kg dosing were compared with those initiated taking 10 mg/kg with regard to treatment durability. RESULTS: Overall, 26.4%, 58.3%, and 70% with limited, moderate, or extensive disease, respectively, started taking a standard IFX dose of 5 mg/kg required therapy escalation. Patients with moderate and extensive disease, started taking the 5 mg/kg per dose, showed statistically significant shorter times to escalation than those with limited disease. The percentage of patients remaining on their initial 5 mg/kg per dose at 12 months was 80.1%, 56.9%, and 40.0% for limited, moderate, and extensive disease, respectively. Among patients started taking 10 mg/kg, 100% remained on this dose. All the patients with limited disease who required dose escalation continued on the higher dose at the time of analysis; however, among those with the most extensive disease, 43% failed escalation because of nonresponse or infusion reaction. CONCLUSIONS: Patients with extensive disease started taking 5 mg/kg of IFX were more likely to require dose escalation compared to those with limited or moderate disease. All of the patients with moderate and extensive disease started taking 10 mg/kg of IFX remained on this dose. These results suggest that patients with more extensive disease may benefit from higher initial IFX dosing as it relates to durability of the treatment.

Corticosteroid Use in a Prospective, Community-Based Cohort of Newly Diagnosed Inflammatory Bowel Disease Patients.

BACKGROUND: Systemic corticosteroids (CS) are a mainstay of treatment for patients with newly diagnosed inflammatory bowel disease (IBD). Previous population-based studies report CS exposure rates range from 39 to 75 % within the first year of diagnosis with surgical resection rates as high as 13-18 % in the same time frame. These reports represent an older cohort of patients enrolled over prolonged periods of time and do not necessarily reflect current treatment approaches. We examine CS use during the first year of IBD diagnosis in a community-based, inception cohort. METHODS: Data were derived from the Ocean State Crohn's and Colitis Area Registry (OSCCAR), a prospective inception cohort of IBD patients who are residents of Rhode Island. RESULTS: A total of 272 patients were included in the current analyses. Overall, 60 % of Crohn's disease and 57 % of ulcerative colitis patients were exposed to at least one course of CS during year 1 of study enrollment. Most notably, only 2 % of patients (n = 5) required a surgical resection. CONCLUSIONS: In this community-based cohort, 59 % of patients were exposed to at least one course of CS during their first year of enrollment. In contrast to previous studies, OSCCAR represents a more modern cohort of patients. While steroid exposure rates were similar or slightly higher than those in previous reports, we observed a low rate of surgical resection. As our cohort ages, future analysis will focus on the role more contemporary agents may play on the low rates of surgery we observed.