Early Onset Inflammatory Bowel Disease Research Articles

Comprehensive Targeted Sequencing Identifies Monogenic Disorders in Patients With Early-onset Refractory Diarrhea.

Causes of early-onset refractory diarrhea include exudative diarrhea associated with very early-onset inflammatory bowel diseases, osmotic or secretory diarrhea, and protein-losing enteropathy. Monogenic disorders are included in these diseases, yet a comprehensive genetic analysis has not been fully established. We established targeted gene panels covering all responsible genes for early-onset diarrhea. In total, 108 patients from 15 institutions were enrolled in this study. We collected clinical data from all patients. Seventy-three patients with exudative diarrhea, 4 with osmotic or secretory diarrhea and 8 with protein-losing enteropathy were subjected to genetic analysis. A total of 15 out of the 108 enrolled patients (13.9%) were identified as monogenic. We identified 1 patient with RELA, 2 with TNFAIP3, 1 with CTLA4, 1 with SLCO2A1, 4 with XIAP, 3 with IL10RA, 1 with HPS1, 1 with FOXP3, and 1 with CYBB gene mutations. We also identified 1 patient with NFKB2 and 1 with TERT mutations from the gene panel for primary immunodeficiency syndromes. The patient with refractory diarrhea caused by heterozygous truncated RelA protein expression is the first case identified worldwide, and functional analysis revealed that the mutation affected nuclear factor kappa B signaling. Genotypes were significantly associated with the clinical and pathological findings in each patient. We identified variable monogenic diseases in the patients and found that genes responsible for primary immunodeficiency diseases were frequently involved in molecular pathogenesis. Comprehensive genetic analysis was useful for accurate molecular diagnosis, understanding of underlying pathogenesis, and selecting the optimal treatment for patients with early-onset refractory diarrhea.An infographic for this article is available at: http://links.lww.com/MPG/B853.

Monogenic Very Early Onset Inflammatory Bowel Disease in Children. A Report of Two Cases and Literature Review

Monogenic Very Early Onset Inflammatory Bowel Disease in Children. A Report of Two Cases and Literature Review

Runx3 prevents spontaneous colitis by directing the differentiation of anti-inflammatory mononuclear phagocytes.

Mice deficient in the transcription factor Runx3 develop a multitude of immune system defects, including early onset colitis. This paper demonstrates that Runx3 is expressed in colonic mononuclear phagocytes (MNP), including resident macrophages (RM) and dendritic cell subsets (cDC2). Runx3 deletion in MNP causes early onset colitis due to their impaired maturation. Mechanistically, the resulting MNP subset imbalance leads to up-regulation of pro-inflammatory genes as occurs in IL10R-deficient RM. In addition, RM and cDC2 display a marked decrease in expression of anti-inflammatory/TGF β-regulated genes and β-catenin signaling associated genes, respectively. MNP transcriptome and ChIP-seq data analysis suggest that a significant fraction of genes affected by Runx3 loss are direct Runx3 targets. Collectively, Runx3 imposes intestinal immune tolerance by regulating maturation of colonic anti-inflammatory MNP, befitting the identification of RUNX3 as a genome-wide associated risk gene for various immune-related diseases in humans, including gastrointestinal tract diseases such as Crohn’s disease and celiac.

A Multicenter Prospective Survey on Early-Onset Inflammatory Bowel Disease in Japan

Introduction: The incidence of early-onset inflammatory bowel disease is increasing in Japan. Objective: This study aimed to analyze the treatment and progress of early-onset inflammatory bowel disease. Methods: This prospective survey evaluated the data of 43 patients aged <8 years who were diagnosed with inflammatory bowel disease (IBD) from the time of diagnosis to 36 months after registration. Results: A total of 12 patients with Crohn’s disease (CD), 21 with ulcerative colitis (UC), and 3 with unclassified IBD were enrolled. The mean disease onset age was 3 years and 7 months. Colon and anal lesions were present in 100 and 50% of patients with CD, respectively. Granulomas were detected in 5 patients (41.7%). Dietary elimination including elemental diet was performed in all patients. Eleven patients (91.7%) were in remission by initial induction therapy, and 72.7% maintained remission for 36 months. Three patients (14.3%) with UC had familial history, 71.4% had pancolitis-type UC, and 66.7% exhibited disease of moderate severity. Colectomy was performed in 4 patients (21.1%). Eighteen patients (85.7%) were in remission by initial induction therapy; however, only 15.8% maintained remission for 36 months. Anal complication was more prevalent in infantile-onset IBD than in childhood-onset IBD (p = 0.014). Conclusions: Among Japanese patients aged <8 years who were diagnosed with IBD, colitis-type disease was more common in CD and pancolitis was more common in UC. As the courses of several patients were severe, identifying primary immunodeficiency appears to be necessary to confirm background disease.

Natural History of Very Early Onset Inflammatory Bowel Disease in North America: A Retrospective Cohort Study.

The incidence of very early onset inflammatory bowel disease (VEOIBD) is increasing, yet the phenotype and natural history of VEOIBD are not well described. We performed a retrospective cohort study of patients diagnosed with VEOIBD (6 years of age and younger) between 2008 and 2013 at 25 North American centers. Eligible patients at each center were randomly selected for chart review. We abstracted data at diagnosis and at 1, 3, and 5 years after diagnosis. We compared the clinical features and outcomes with VEOIBD diagnosed younger than 3 years of age with children diagnosed with VEOIBD at age 3 to 6 years. The study population included 269 children (105 [39%] Crohn's disease, 106 [39%] ulcerative colitis, and 58 [22%] IBD unclassified). The median age of diagnosis was 4.2 years (interquartile range 2.9-5.2). Most (94%) Crohn's disease patients had inflammatory disease behavior (B1). Isolated colitis (L2) was the most common disease location (70% of children diagnosed younger than 3 years vs 43% of children diagnosed 3 years and older; P = 0.10). By the end of follow-up, stricturing/penetrating occurred in 7 (6.6%) children. The risk of any bowel surgery in Crohn's disease was 3% by 1 year, 12% by 3 years, and 15% by 5 years and did not differ by age at diagnosis. Most ulcerative colitis patients had pancolitis (57% of children diagnosed younger than 3 years vs 45% of children diagnosed 3 years and older; P = 0.18). The risk of colectomy in ulcerative colitis/IBD unclassified was 0% by 1 year, 3% by 3 years, and 14% by 5 years and did not differ by age of diagnosis. Very early onset inflammatory bowel disease has a distinct phenotype with predominantly colonic involvement and infrequent stricturing/penetrating disease. The cumulative risk of bowel surgery in children with VEOIBD was approximately 14%-15% by 5 years. These data can be used to provide anticipatory guidance in this emerging patient population.

Effect of Age on the Initiation of Biologic Agent Therapy in Patients With Inflammatory Bowel Disease: Korean Common Data Model Cohort Study.

BackgroundThe Observational Health Data Sciences and Informatics (OHDSI) network is an international collaboration established to apply open-source data analytics to a large network of health databases, including the Korean common data model (K-CDM) network.ObjectiveThe aim of this study is to analyze the effect that age at diagnosis has on the prognosis of inflammatory bowel disease (IBD) in Korea using a CDM network database.MethodsWe retrospectively analyzed the K-CDM network database from 2005 to 2015. We transformed the electronic medical record into the CDM version 5.0 used in OHDSI. A worsened IBD prognosis was defined as the initiation of therapy with biologic agents, including infliximab and adalimumab. To evaluate the effect that age at diagnosis had on the prognosis of IBD, we divided the patients into an early-onset (EO) IBD group (age at diagnosis <40 years) and a late-onset (LO) IBD group (age at diagnosis ≥40 years) with the cutoff value of age at diagnosis as 40 years, which was calculated using the Youden index method. We then used the logrank test and Cox proportional hazards model to analyze the effect that age at diagnosis (EO group vs LO group) had on the prognosis in patients with IBD.ResultsA total of 3480 patients were enrolled. There was 2017 patients with ulcerative colitis (UC) and 1463 with Crohn’s disease (CD). The median follow up period was 109.5 weeks. The EO UC group was statistically significant and showed less event-free survival (ie, experiences of biologic agents) than the LO UC group (P<.001). In CD, the EO CD group showed less event-free survival (ie, experiences of biologic agents) than the LO CD group. In the Cox proportional hazard analysis, the odds ratio (OR) of the EO UC group on experiences of biologic agents compared with the LO UC group was 2.3 (95% CI 1.3-3.8, P=.002). The OR of the EO CD group on experiences of biologic agents compared with the LO CD group was 5.4 (95% CI 1.9-14.9, P=.001).ConclusionsThe EO IBD group showed a worse prognosis than the LO IBD group in Korean patients with IBD. In addition, this study successfully verified the CDM model in gastrointestinal research.

2019 Harry Shwachman Award

2019 Harry Shwachman Award

Genetic diagnosis of autoinflammatory disease patients using clinical exome sequencing.

Autoinflammatory diseases comprise a wide range of syndromes caused by dysregulation of the innate immune response. They are difficult to diagnose due to their phenotypic heterogeneity and variable expressivity. Thus, the genetic origin of the disease remains undetermined for an important proportion of patients. We aim to identify causal genetic variants in patients with suspected autoinflammatory disease and to test the advantages and limitations of the clinical exome gene panels for molecular diagnosis. Twenty-two unrelated patients with clinical features of autoinflammatory diseases were analyzed using clinical exome sequencing (~4800 genes), followed by bioinformatic analyses to detect likely pathogenic variants. By integrating genetic and clinical information, we found a likely causative heterozygous genetic variant in NFKBIA (p.D31N) in a North-African patient with a clinical picture resembling the deficiency of interleukin-1 receptor antagonist, and a heterozygous variant in DNASE2 (p.G322D) in a Spanish patient with a suspected lupus-like monogenic disorder. We also found variants likely to increase the susceptibility to autoinflammatory diseases in three additional Spanish patients: one with an initial diagnosis of juvenile idiopathic arthritis who carries two heterozygous UNC13D variants (p.R727Q and p.A59T), and two with early-onset inflammatory bowel disease harbouring NOD2 variants (p.L221R and p.A728V respectively). Our results show a similar proportion of molecular diagnosis to other studies using whole exome or targeted resequencing in primary immunodeficiencies. Thus, despite its main limitation of not including all candidate genes, clinical exome targeted sequencing can be an appropriate approach to detect likely causative variants in autoinflammatory diseases.

North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition Position Paper on the Evaluation and Management for Patients With Very Early-onset Inflammatory Bowel Disease.

The rate of pediatric inflammatory bowel disease (IBD) has been increasing over the last decade and this increase has occurred most rapidly in the youngest children diagnosed <6 years, known as very early-onset inflammatory bowel disease (VEO-IBD). These children can present with more extensive and severe disease than older children and adults. The contribution of host genetics in this population is underscored by the young age of onset and the distinct, aggressive phenotype. In fact, monogenic defects, often involving primary immunodeficiency genes, have been identified in children with VEO-IBD and have led to targeted and life-saving therapy. This position paper will discuss the phenotype of VEO-IBD and outline the approach and evaluation for these children and what factors should trigger concern for an underlying immunodeficiency. We will then review the immunological assays and genetic studies that can facilitate the identification of the underlying diagnosis in patients with VEO-IBD and how this evaluation may lead to directed therapies. The position paper will also aid the pediatric gastroenterologist in recognizing when a patient should be referred to a center specializing in the care of these patients. These guidelines are intended for pediatricians, allied health professionals caring for children, pediatric gastroenterologists, pediatric pathologists, and immunologists.

A171 MAGNETIC RESONANCE IMAGING IN CHILDREN WITH EARLY ONSET INFLAMMATORY BOWEL DISEASE- A RETROSPECTIVE COHORT STUDY

Abstract Background Magnetic Resonance (MR) Imaging is the preferred imaging method in Inflammatory Bowel Disease (IBD) patients to investigate for small bowel disease. There are challenges in performing MR imaging in Early Onset IBD (EO-IBD) patients, and in particular in children with Very Early Onset IBD (VEO-IBD). These children often need a general anaesthetic which exposes them to adverse effects and preclude conventional luminal distention influencing the quality of the test. Therefore, the utility of MR imaging in this age group is questionable. Aims To assess the quality of MRI studies in VEO-IBD and EO-IBD patients and to compare the utility of this test between the two groups. Methods We retrospectively identified and reviewed IBD patients diagnosed under 10 years of age, between January 1999 and December 2011, from the British Columbia Children’s Hospital (BCCH) GI Division IBD database. Patients’ first diagnostic MRI results were recorded. Disease location and severity were documented according to the Paris classification. Results 124 patients were included in the cohort, 54 VEO-IBD and 70 EO-IBD patients (See Table 1). Median age at diagnosis was 6.46 (IQR 3.94–8.71), 65.32% males and 43.54% were diagnosed with Crohn’s disease. Overall, 52 patients underwent MRI, 17 (31.48%) in the VEO-IBD group and 35 (50%) in the EO-IBD group; median time from diagnosis to MRI was 3.02 years (IQR 1.08–5.83) for VEO-IBD and 0.44 years (IQR 0.07–1.58) for EO-IBD (p&amp;lt;0.001). In the EO-IBD group there was a significantly higher percentage of patients with MRI findings than in the VEO-IBD group, 23 (67.31%) and 5 (29.41%) respectively (p=0.014). Only one patient in the VEO-IBD group had a disease characteristic identified by MR imaging that could not be diagnosed by endoscopy (small bowel disease). Conclusions The diagnostic yield of MRI in children with VEO-IBD appears to be quite limited but requires further study. Funding Agencies None

A106 TTC7A MUTATION AND CHRONIC PRURITUS, A CASE REPORT

Abstract Background TTC7A mutation is a rare autosomal recessive disease that can present with various phenotypes including multiple intestinal atresia (MIA), very early onset inflammatory bowel disease (VEOIBD), and profound combined immunodeficiency with hypoplastic thymus, altered T- and B-cell maturation, lymphopenia, monocytosis and agammaglobulinemia. Although TTC7A mutation mostly affects immune and gut function, it is a multisystemic disease. Chronic pruritus has not been described yet. Aims To describe the case of a child with TTC7A mutation with chronic pruritus and the potential treatment options. Methods Case report and review of literature Results We report a child with TTC7A mutation who developed severe chronic pruritus. The child presented ileal atresia and pyloric stenosis and underwent ileo-caecal resection and pyloroplasty at birth. She required a latero-lateral anastomosis between the stomach and the duodenum because of recurring pyloric stenosis and several dilatations of her ileo-colic anastomosis. She remained dependant on parenteral nutrition for most of her caloric needs. Her immune deficiency manifested with a very low lymphocyte count and low immunoglobulins. She had pneumocystis Carinii infection at 3 months of age and was put on gammaglobulin injections and pentamidine prophylaxis. At 3 years of age, she developed severe pruritus that led to skin infection and recurrent Staphylococcus Aureus sepsis. A skin biopsy revealed eczematous dermatitis with eosinophilic infiltration. Various treatments were attempted. Replacing lipid fat emulsion by fish oil emulsion in her parenteral nutrition did not improve her symptoms. Amitryptiline, gabapentine, hydroxyzine hydrochloride and levofloxacine also failed. Corticosteroids seemed to have a mild effect. A trial of Mepolizumab (anti-IL 5) was unsuccessful. At age of 4, after a sepsis treated by vancomycin, she presented with severe bullous skin disease. Skin biopsy was compatible with linear IgA bullous dermatosis. She was put on dupilumab and systemic corticosteroids. Dupilumab inhibits signaling of both IL-4 and IL-13, two cytokines involved in inflammation that contribute to atopic dermatitis. With this combination of IV steroids and dupilumab, pruritus has improved significantly. Conclusions Our patient’s evolution suggests that some TTC7A mutation can be complicated with severe pruritus and IgA linear bullosis. Skin disease, combined with immunodeficiency and the presence of a central line can lead to life threatening sepsis. Pruritus did not respond to usual treatments but improved the combination of intravenous steroids and dupilumab suggesting a role of IL-4 and IL-13 in the pathophysiology of the pruritus associated with this disease. Hematopoietic stem cell transplantation, may be an alternative solution. Funding Agencies None

A251 VERY EARLY ONSET INFLAMMATORY BOWEL DISEASE IN CHILDREN: A SINGLE CENTER EXPERIENCE OVER 15 YEARS

Abstract Background Very-early-onset inflammatory bowel disease (VEOIBD) refers to an IBD diagnosis established before the 6th year of life, including a subset of patients with disease onset before the age of 2 years, known as infantile-onset IBD (IO-IBD) (1). VEO-IBD accounts for 15% of pediatric IBD and infantile IBD in approximately 1% (2,3). VEOIBD is considered to be a unique entity, and compared to adults with IBD, VEO-IBD children are more likely to present with extensive and treatment-resistant disease (4). Aims To analyze the clinical characteristics and management of patients diagnosed with very early onset inflammatory bowel disease (VEO-IBD). Methods A retrospective analysis of children diagnosed with VEO-IBD (age &amp;lt;6 years) at the Montreal Children’s Hospital from 2003–2018 was performed. Clinical data for VEO-IBD patients was collected to identify the clinical, biochemical, endoscopic and histological features of these patients and their clinical course until 2018. Results A total of 28 VEO-IBD patients (71% male) were included in this study. The median age of disease onset was 52 months. A diagnosis of Crohn’s disease (CD) or CD-like intestinal manifestations accounted for 89% of the VEO-IBD cases. Most patients had Crohn’s colitis (36%) of whom 50% had evidence of granulomatous Crohn’s disease; 11 patients[NAD1] [AQAB2] (39%) had upper gastrointestinal involvement. Over their progress of the disease, 4 patients (14%) required surgical intervention, while 11 patients (39%) required biologic therapy for maintenance therapy. Genetic[NAD3] [AQAB4] results were available for 5 patients out of 28 (18%) and 3 of them were identified to have monogenic IBD. Conclusions In our center, the majority of patients with VEO-IBD had typical Crohn’s disease presentation. Most of the VEO-IBD patients responded well to the standard IBD treatment. Genetic studies were not done regularly for all of our patients, however, among those who had this testing performed 3/5 had an identifiable cause, suggesting that these patients should be investigated for an underlying genetic abnormality. Funding Agencies None

The Dual Role of Reactive Oxygen Species-Generating Nicotinamide Adenine Dinucleotide Phosphate Oxidases in Gastrointestinal Inflammation and Therapeutic Perspectives.

Significance: Despite their intrinsic cytotoxic properties, mounting evidence indicates that reactive oxygen species (ROS) physiologically produced by the nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs) of epithelial cells (NOX1, dual oxidase [DUOX]2) and phagocytes (NOX2) are critical for innate immune response and homeostasis of the intestinal mucosa. However, dysregulated ROS production could be a driving factor in inflammatory bowel diseases (IBDs). Recent Advances: In addition to NOX2, recent studies have demonstrated that NOX1- and DUOX2-derived ROS can regulate intestinal innate immune defense and homeostasis by impacting many processes, including bacterial virulence, expression of bacteriostatic proteins, epithelial renewal and restitution, and microbiota composition. Moreover, the antibacterial role of DUOX2 is a function conserved in evolution as it has been described in invertebrates, and lower and higher vertebrates. In humans, variants of the NOX2, NOX1, and DUOX2 genes, which are associated with impaired ROS production, have been identified in very early onset IBD, but overexpression of NOX/DUOX, especially DUOX2, has also been described in IBD, suggesting that loss-of-function or excessive activity of the ROS-generating enzymes could contribute to disease progression. Critical Issues: Therapeutic perspectives aiming at targeting NOX/DUOX in IBD should take into account the two sides of NOX/DUOX-derived ROS in intestinal inflammation. Hence, NOX/DUOX inhibitors or ROS inducers should be considered as a function of the disease context. Future Directions: A thorough understanding of the physiological and pathological regulation of NOX/DUOX in the gastrointestinal tract is an absolute pre-requisite for the development of therapeutic strategies that can modulate ROS levels in space and time.

A33 THE ROLE OF A HOMOZYGOUS PROTEIN CODING VARIANT OF EPS8 IN THE PATHOGENESIS OF PEDIATRIC IBD

Abstract Background The rate of onset for Inflammatory Bowel Disease (IBD) is rising worldwide—most significantly in the pediatric population. The pathogenesis of the disease involves a complicated interaction between the environment and genetics. Recent findings suggest that there is a broad range of rare, single-gene mutations that correlate with the IBD phenotype in children. Some of these single-gene defects can disrupt the epithelial barrier, which alters intestinal immune homeostasis. Epidermal Growth Factor Receptor Kinase Substrate 8 (EPS8) is crucial for the stabilization of F-actin by capping and bundling the barbed end. Previous literature shows that loss of expression of EPS8 disrupts the polymerization of F-actin in intestinal microvilli resulting in shortened brush borders. We identified a pediatric IBD patient with a homozygous missense EPS8 mutation(c.2099C&amp;gt;T, I700T) in the actin-binding domain. The patient presented with pancolitis, colonic strictures and other IBD-like symptoms at 6 weeks of age. Currently, the functional role of EPS8 in the pathogenesis of very early-onset IBD remains elusive. Aims 1)To investigate if the patient with EPS8 mutation has microvilli disorganization. 2)To determine EPS8 localization in patient samples and cell models. 3)To clarify the mechanism of how the EPS8 mutation affects F-actin in vitro. Ultimately, we want to clarify how the mutation of EPS8 might contribute to the onset of pediatric IBD. Methods A rare, damaging mutation in EPS8 was identified in a very early-onset IBD patient by Whole Exome Sequencing. From patient-derived colon biopsy samples, the localization of EPS8 and actin was visualized by immunofluorescence (IF) microscopy. The morphology of the patient’s intestinal microvilli was assessed using transmission electron microscopy (TEM). EPS8 expression was measured using western blot. An F-actin polymerization assay was performed comparing purified WT and mutant EPS8 protein to assess the rate of polymerization from monomeric G-actin to F-actin. Results IF microscopy of the colonic sections revealed lower co-localization of EPS8 and actin on the apical surfaces, compared to IBD and normal controls. Closer examination of the cell structure using TEM showed disruption of the microvilli in the EPS8 mutant, but not in IBD or normal controls. Western blots showed no differences in protein expression between wildtype and mutant EPS8 in HEK293T cells. F-actin polymerization assay revealed differences in the rate of G-actin to F-actin polymerization between wildtype and mutant EPS8. Conclusions The patient with EPS8 mutation had microvilli disorganization. EPS8 localized differently in the patient colon tissues compared to normal and IBD control samples. The EPS8 mutation may affect F-actin polymerization, which may lead to disruption of the microvilli. Funding Agencies CIHR

A39 NOVEL GAIN OF FUNCTION NON-RECEPTOR TYROSINE KINASE MUTATIONS ARE LINKED TO THE PATHOGENESIS OF VEOIBD

Abstract Background Very early-onset inflammatory bowel disease (VEOIBD) is an emerging global disease, that results in inflammation of the digestive tract. Severe forms of VEOIBD can be caused by mutations in a single gene (monogenic variants) and, can result in death. A candidate gene which codes for a non-receptor tyrosine kinase (nRTK) has recently been implicated as a monogenic cause of IBD (unpublished). Whole exome sequencing was performed in two unrelated children who presented with symptoms of IBD identifying two distinct de novo gain of function mutations (S550Y and P342T). Both mutations are located in the highly conserved region of the nRTK, and were predicted to have similar downstream effects. Furthermore, four other patients with a variety of adult-onset immune disorders have recently been identified with rare variants in the same gene (M450I, R42P, A353T, V433M, S550F) but, their potential gain of function status remains to be determined. Studies show that this nRTK is an essential mediator in inflammation. It is expressed in both intestinal epithelial and immune cells however, its role in infantile IBD is unclear. This protein is first activated by phosphorylation and is linked to activating downstream transcription factors such as ERK and JNK. All these target proteins play a meaningful role in intestinal inflammation in patients with IBD. Aims Since we identified P342T and S550Y to be gain of function, we wanted to determine if the new variants exhibit a similar downstream impact on target protein expression levels when compared with S550Y and P342T. We also wanted to identify if all variants can be rescued with a known nRTK inhibitor. It is hypothesized that the new variants are gain of function and that all variants can be rescued with the inhibitor. Methods Using western blot analysis, the activation of ERK, JNK and nRTK was compared between wildtype (WT) and mutants. This in vitro method helped identify the degree of activation. For the second part of the study, HEK293T cells were treated with inhibitor to test for a rescue of phenotypes via western blot analysis. Results Results show an increased activation of nRTK, ERK and JNK in all variants with S550Y and S550F having the highest activation. Furthermore, pharmacological inhibition using small molecular kinase inhibitors resulted in decreased activation of nRTK, ERK and JNK suggesting a rescue of phenotypes. Conclusions Characterizing the downstream functional impact of these nRTK variants is an important first step to determine if gain of function nRTK mutations drive IBD. With a rising prevalence of IBD worldwide, these findings may lead to the development of pharmacological nRTK inhibitors as a novel personalized therapeutic approach for these patients and possibly for the broader IBD population. Funding Agencies CIHR

Development of Physiologically Responsive Human iPSC-Derived Intestinal Epithelium to Study Barrier Dysfunction in IBD.

In inflammatory bowel disease (IBD), the intestinal epithelium is characterized by increased permeability both in active disease and remission states. The genetic underpinnings of this increased intestinal permeability are largely unstudied, in part due to a lack of appropriate modelling systems. Our aim is to develop an in vitro model of intestinal permeability using induced pluripotent stem cell (iPSC)-derived human intestinal organoids (HIOs) and human colonic organoids (HCOs) to study barrier dysfunction. iPSCs were generated from healthy controls, adult onset IBD, and very early onset IBD (VEO-IBD) patients and differentiated into HIOs and HCOs. EpCAM+ selected cells were seeded onto Transwell inserts and barrier integrity studies were carried out in the presence or absence of pro-inflammatory cytokines TNFα and IFNγ. Quantitative real-time PCR (qRT-PCR), transmission electron microscopy (TEM), and immunofluorescence were used to determine altered tight and adherens junction protein expression or localization. Differentiation to HCO indicated an increased gene expression of CDX2, CD147, and CA2, and increased basal transepithelial electrical resistance compared to HIO. Permeability studies were carried out in HIO- and HCO-derived epithelium, and permeability of FD4 was significantly increased when exposed to TNFα and IFNγ. TEM and immunofluorescence imaging indicated a mislocalization of E-cadherin and ZO-1 in TNFα and IFNγ challenged organoids with a corresponding decrease in mRNA expression. Comparisons between HIO- and HCO-epithelium show a difference in gene expression, electrophysiology, and morphology: both are responsive to TNFα and IFNγ stimulation resulting in enhanced permeability, and changes in tight and adherens junction architecture. This data indicate that iPSC-derived HIOs and HCOs constitute an appropriate physiologically responsive model to study barrier dysfunction and the role of the epithelium in IBD and VEO-IBD.

Cardiac functions and aortic elasticity in children with inflammatory bowel disease: effect of age at disease onset

Childhood onset inflammatory bowel disease is more aggressive and has rapidly progressive clinical course than adult inflammatory bowel disease. Early-onset inflammatory bowel disease has more severe clinical progression as a subspecialised group of monogenic inflammatory bowel disease. We studied cardiac functions and aortic elasticity in children with early- and late-onset inflammatory bowel disease in remission period. Thirty-three paediatric patients were divided into subgroups according to age of disease onset (<10 and >10 years of age). Twenty-five healthy children were admitted as control group. M-Mode echocardiography and pulsed wave Doppler echocardiography were performed. Strain, distensibility, stiffness index of ascending, and abdominal aorta were evaluated. Interventricular septum (mm) and left ventricular end-systolic diameter were higher (6.9 ± 1.2, 26.2 ± 4.6) in early-onset inflammatory bowel disease patients than control patients (6.1 ± 1.27, 22.7 ± 4.12) (p = 0.050, p = 0.050). Mitral E/E' ratio and myocardial performance index were increased in inflammatory bowel disease and early-onset inflammatory bowel disease groups than control group (p = 0.046, p = 0.04; p = 0.023, p = 0.033). Diastolic functions were found to beimpaired in inflammatory bowel disease and early-onset inflammatory bowel disease groups according to control group, while there was no difference between late-onset inflammatory bowel disease and control groups in terms of diastolic functions. Mitral E/A ratio was lower in inflammatory bowel disease patients and early-onset inflammatory bowel disease patients (1.46 ± 0.32, 1.4 ± 0.21) than control patients (1.70 ± 0.27) (p = 0.013, p = 0.004). Aortic elasticity did not differ between groups. Chronic low-grade inflammation has effects on left ventricular diameters and diastolic function in remission period. Aortic elasticity is not affected in our study groups.

P173 Very–Early-Onset inflammatory bowel disease: Russian single centre experience

Abstract Background The incidence of very early-onset inflammatory bowel disease (VEOIBD) is on the rise in Russia but the clinical data is lacking. We aim to study the disease phenotype, clinical course and the presence of primary immunodeficiency (PID) patients in this group. Methods Clinical records of VEOIBD patients treated in Russian State Pediatric Hospital between 2000 and 2018 were revised. In 60 patients admitted between 2016 and 2018 targeted sequencing (PID panel) was performed. 10 patients received genetic testing previously. Results 135 VEOIBD patients were identified: 95 (70%)with ulcerative colitis (UC), 31 (23%) with Crohn’s disease, 9 (7%) with PID. In 14 (11%) IBD patients the diagnosis was changed from UC to CD and vice versa. Median time of diagnosis was 7 months in UC, 24 months in CD and 44 months in PID. The most common clinical symptoms were loose stools (UC—98%, CD—84%), bloody stools (UC—93, CD—65%), stomach ache (UC—53%, CD—52%), fever (UC—35%, CD—42%). Common laboratory features included anemia (UC—56%, CD—39%), low serum ferrum level (UC—75%, CD—61%), thrombocytosis (UC—53%, CD—45%). From 103 patients tested for ANCA 26% had positive results (24—UC, 3—CD). Mean calprotectin level (76 patients) was 750 ± 54.4 μg/g. Pancolitis was seen in UC (84%), as well as in CD (61%). Epithelioid granulomas in CD were present in 7 patients, in 5 of them they were detected years after initial diagnosis. Sixty-nine% of UC and 90% of CD patients received steroids as induction therapy, steroid-dependency was common (42% in UC and 55% in CD). Forty-nine% of patients with UC and 23% od CD patients received azathioprine, anti-TNF agents were used in 26% UC patients and 77% CD patients. In 35% of patients receiving anti-TNF biologic therapy was started before the age of 6 years. 23,8% of VEOIBD patients failed to achieve clinical remission. Total colectomy was performed in 11 patients, in 3 of them the diagnosis was subsequently changed to CD. Segmental resection was performed in 9 CD patients, in 3 of them while on therapy. The most common form of PID was XIAP deficiency (3 patients), 2 of them achieved endoscopic remission after allogenic stem cell transplantation. Conclusion In the VEOIBD group CD resembles UC clinically and endoscopically. A substantial number of patients requires immunosuppressive and biologic therapy before the age of 6 years. Colectomy rates are still high regardless the use of biologics. Boys with refractory VEOIBD should be screened for XIAP deficiency.

Complications of enterostomy and related risk factor analysis of very early onset inflammatory bowel disease with interleukin-10 signalling deficiency: a single-centre retrospective analysis

BackgroundInterleukin-10 (IL10) signalling pathway deficiency results in severe very early onset inflammatory bowel disease (VEOIBD), and enterostomy is often inevitable. However, studies in these surgical populations are lacking. This study aims to determine the enterostomy characteristics, postoperative complications and related risk factors in enterostomy patients.MethodsFrom March 1, 2015, to December 31, 2018, patients with IL10R-mutation who underwent enterostomy were recruited for analysis. We collected data on the patients’ clinical characteristics, enterostomy characteristics, postoperative complications and related risk factors.ResultsTwelve patients required emergency enterostomy, and 10 patients underwent elective enterostomy. Twelve patients experienced postoperative complications, including wound infection (27.3%), wound dehiscence (18.2%), reoperation (18.2%), etc. Compared with the pre-enterostomy values, there was a decrease in C-reactive protein (CRP) (P = 0.001), an increase in albumin (P = 0.001) and an improvement in the weight-for-age (P = 0.029) and body mass index (BMI) Z-scores (P = 0.004) after enterostomy. There was a significant difference between the pre-operation and postoperation medicine expenses (P = 0.002). Univariate binary logistic regression analysis revealed a statistically significant influence of CRP (OR: 1.43, 95% CI: 1.07–1.91, P = 0.016) and a tendency towards a significant influence of intestinal perforation, albumin level, BMI Z-score and weighted paediatric Crohn’s disease activity index (wPCDAI). Multivariate logistic regression analysis showed that CRP (OR: 1.40), wPCDAI (OR: 2.88) and perforation (OR: 1.72) showed a tendency to behave as independent risk factors for postoperative complications, but the results were not significant (all P > 0.05).ConclusionsSurgery and enterostomy showed benefits for VEOIBD with IL-10 signalling deficiency. The timing of intervention, potential postoperative complications, economic burden and other related problems should be considered.

A Retrospective Study of 73 Chinese Children with Very Early Onset Inflammatory Bowel Disease (VEO-IBD): Searching for Laboratory Indicators for Early Screening of Patients with Monogenic VEO-IBD

A Retrospective Study of 73 Chinese Children with Very Early Onset Inflammatory Bowel Disease (VEO-IBD): Searching for Laboratory Indicators for Early Screening of Patients with Monogenic VEO-IBD