Pediatric Inflammatory Bowel Disease Research Articles

Priming lymphocyte responsiveness and differential T cell signaling in pediatric IBD patients with Cannabis use.

The prevalence of inflammatory bowel disease (IBD) has increased dramatically in recent years, particularly in pediatric populations. Successful remission with current therapies is limited and often transient, leading patients to seek alternative therapies for symptom relief, including the use of medical marijuana (Cannabis sativa). However, chronic cannabis use among IBD patients is associated with increased risk for surgical interventions. Therefore, determining the direct impact of cannabis use on immune modulation in IBD patients is of critical importance. Peripheral blood mononuclear cells of cannabis using and non-using pediatric IBD patients were phenotyped by flow cytometry and functionally assessed for their cytokine production profile. A phospho-kinase array was also performed to better understand changes in immune responses. Results were then compared with serum phytocannabinoid profiles of each patient to identify cannabinoid-correlated changes in immune responses. Results demonstrated elevated levels of a myriad of pro-inflammatory cytokines in users versus non-users. Differences in signaling cascades of activated T cells between users and non-users were also observed. A number of anti-inflammatory cytokines were inversely correlated with serum phytocannabinoids. These results suggest that cannabis exposure, which can desensitize cannabinoid receptors, may prime pro-inflammatory pathways in pediatric IBD patients.

Improved high-performance liquid chromatography tandem mass spectrometry method for quantification of infliximab in pediatric plasma and its application in therapeutic drug monitoring.

The application of infliximab (IFX) to immune-mediated disease is limited by the significant individual variability and associated clinical nonresponse, emphasizing the importance of therapeutic drug monitoring (TDM). Because of the cross-reactivity, limited linear range, and high costs, the clinical application of the previous reported methods was limited. Here, an improved high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method was developed to address the issues. This study developed an improved bioanalytical HPLC-MS/MS method coupling nanosurface and molecular-orientation limited proteolysis technology. The commercially available compound P14R was selected as the internal standard. This method was developed with fewer volume of reagents and was thoroughly validated. The validated method was applied to TDM in pediatric inflammatory bowel disease (IBD). Chromatography was performed using a Shim-pack GISS-HP C18 metal-free column (3 μm, 2.1 × 100 mm) with a gradient elution of 0.1% formic acid in water and acetonitrile at 0.4 mL/min. Detection and quantitation were performed using electrospray ionization (ESI) and multiple reaction monitoring in the positive ion mode. The method was validated to demonstrate its selectivity, linearity, accuracy, precision, recovery, matrix effect, and stability. The method exhibited a linear dynamic range of 0.3-100 μg/mL, with intra- and inter-day precision and relative errors below 15%. The recovery and matrix effect were measured as 87.28%-89.72% and 41.98%-67.17%, respectively, which were effectively compensated by the internal standard. A total of 32 samples collected from 24 pediatric patients with IBD were analyzed using the validated method, and only 46.9% achieved the reported targeted trough level. This study developed an improved HPLC-MS/MS method for the quantitative determination of IFX concentration in human plasma. The accurate, reliable, and cost-effective method was validated and utilized in the analysis of clinical samples. The results confirmed the importance of TDM on IFX and the clinical application prospects of the improved method.

Prevalence of Preceding and Follow-up Outpatient Care Surrounding Emergency Department Visits for Pediatric Inflammatory Bowel Disease: Identifying Opportunities for Quality Improvement.

To assess prevalence of outpatient care received before and after emergency department (ED) visits for pediatric patients with inflammatory bowel disease (IBD). Using commercial claims, we identified patients 2-18 years old with IBD and a related ED visit (2015-2018). We identified outpatient visits in 2 weeks before and after ED visits, then used logistic regression to assess relationships between care received and patient characteristics. Forty-one percent received care in 2 weeks before an IBD-related ED visit and 51% in 2 weeks after. High-risk medications and outpatient continuity were associated with higher odds of outpatient care. Gaps in preceding and follow-up care signal opportunities to improve care quality.

A real-life pediatric experience of Crohn's disease exclusion diet at disease onset and in refractory patients.

We aimed to appraise the real-life efficacy of Crohn's disease exclusion diet (CDED) coupled with partial enteral nutrition (PEN) in inducing clinical and biochemical remission at disease onset and in patients with loss of response to biologics and immunomodulators. We retrospectively gathered data of patients aged less than 18 years of age with a diagnosis of Crohn's disease (CD), who received CDED coupled with PEN at a tertiary level pediatric inflammatory bowel disease center. Sixty-six patients were identified. Forty (60.6%) started CDED plus PEN at disease onset and 26 (39.4%) received CDED with PEN as add-on therapy. Forty-six (69.7%) patients achieved clinical remission (weighted Pediatric Crohn's Disease Activity Index < 12.5) at the end of phase 1, 44 (66.7%) normalized c-reactive protein levels (<0.5 mg/dL) and 18 (27.2%) patients normalized calprotectin levels (<150 µg/g). Nine of 19 (47.3%) of patients with clinically severe disease (defined by Physician Global Assessment) achieved clinical remission at the end of phase I. Patients with extraintestinal manifestations had statistically lower clinical response rates to the dietary regimen (p = 0.018). Among patients who received CDED + PEN as add-on treatment, a previous successful course of Exclusive Enteral Nutrition was associated with statistically higher clinical remission rates at Week 8 (p = 0.026). Clinical response at Week 4 was an independent predictor of clinical remission and fecal calprotectin normalization at Week 8 (p = 0.002). CDED with PEN confirmed its efficacy in a real-life setting, proving to be effective also in refractory patients and those with severe disease. Early clinical response predicts clinical remission at the end of phase 1.

Frequency, Types, and Risk Factors of Anemia in Pediatric Inflammatory Bowel Disease

Objective: Inflammatory bowel disease patients are prone to be anemic at diagnosis and follow-up. As it is a common extra-intestinal manifestation, its early identification and treatment are essential. We aimed to evaluate the frequency, types, and predictors of anemia and its treatment in pediatric inflammatory bowel disease patients. Methods: The electronic records of pediatric IBD patients who attended our outpatient clinics between 1 April 2018 and 01 May 2019 were retrospectively evaluated. Patients who had the results of hemoglobin, hematocrit, mean corpuscular volume, iron indices, vitamin B12 level, folic acid level, reticulocyte count, C-reactive protein, and erythrocyte sedimentation rate at least once on a single day were included in the study. Laboratory results associated with anemia and disease activity index scores at three- and six-months follow-ups were recorded. Anemia was diagnosed according to WHO criteria in childhood. Anemia, risk factors, and management of anemia were determined. Results: Forty patients were included in the study. At first evaluation, anemia was observed in 38.1% of Crohn’s disease patients and 57.9% of ulcerative colitis patients. Iron deficiency anemia was the main type of anemia in both groups. The rate of anemia decreased at follow-up. Out of 40 patients, 21 had treatment at the initial evaluation. Active disease was the only predictor of iron deficiency anemia. Conclusion: Anemia was common in pediatric inflammatory bowel disease patients, ranging between 25-47.5% during the 6-month follow-up in our study. Iron deficiency anemia was the main type of anemia. Having active disease was the only risk factor for anemia. The treatment of anemia and iron deficiency without anemia should be kept in mind in parallel with anti-inflammatory treatment.

Clinical impacts of immunomodulator withdrawal from anti-tumor necrosis factor combination therapy in pediatric inflammatory bowel disease.

Combination therapy consists of both anti-tumor necrosis factor (anti-TNF) and an immunomodulator (IMM) and has been shown to improve outcomes in patients with inflammatory bowel disease (IBD). This study assesses the impacts of IMM withdrawal from combination therapy to anti-TNF monotherapy in children with IBD. This single-center retrospective cohort study included children with IBD initiated on combination therapy between 2014 and 2019 who discontinued the IMM. We evaluated whether IMM withdrawal impacts laboratory values and disease activity. Linear mixed effects models with random intercepts were used to compare differences between groups. Chi-square and Kruskal-Wallis tests were used for comparisons between patients who did and did not require subsequent escalation of therapy. One hundred and fifty-two patients discontinued the IMM which did not significantly affect disease activity. However, 18% of patients escalated therapy after IMM withdrawal, primarily due to low anti-TNF levels. Lower anti-TNF and higher erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels before IMM withdrawal were associated with subsequent escalation of therapy. Overall, there was no statistically significant effect on anti-TNF drug levels. Patients with Crohn's disease (CD) on infliximab (IFX) and methotrexate (MTX) who discontinued the IMM had an increase in mean ESR and CRP (p < 0.05). IMM withdrawal from anti-TNF combination therapy may be considered safe in the setting of higher anti-TNF levels and normal serum inflammatory markers. Clinicians should consider assessing anti-TNF levels and inflammatory markers after IMM withdrawal, especially in patients with CD receiving IFX who discontinued MTX.

Liver enzyme profiles after initiating biological treatment in children with inflammatory bowel diseases.

Biological treatments (BTs) are essential in managing pediatric inflammatory bowel diseases (PIBDs). Elevated liver enzymes sometimes succeed BT, yet elucidating studies are scarce. We addressed liver biochemistry after introducing BT and searched for their determinants. We identified PIBD patients receiving infliximab, adalimumab, vedolizumab, or ustekinumab at the Children's Hospital, University of Helsinki, Finland, in 2000-2023, and followed their alanine transaminase (ALT) and γ-glutamyl transpeptidase (GT) levels for 24 months. ALT was categorized based on the age- and sex-specific upper limit of normal. We disregarded 46 patients with underlying primary sclerosing cholangitis with/without autoimmune hepatitis (AIH), pretreatment AIH diagnosis, and elevated liver enzymes at the beginning of BT from the analyses. Of 618 BT episodes in 403 patients, 22.2% exhibited increased ALT or GT (ALT in 117, GT in 4, and both ALT/GT in 16 episodes). Of all ALT elevations (n = 133), 41.4% occurred within the first 3 months. ALT elevation was more common after infliximab (representing 59.5% of BTs) than other BTs (25.9% vs. 14.2%, adjusted odds ratio [OR]: 2.41, 95% confidence interval [CI]: 1.23-4.72). AIH followed 1.5% (n = 9) of BT episodes. Ninety-five percent of ALT elevations resolved within 6 months. Antibiotic exposure (particularly to metronidazole) was associated with ALT elevation in general (adjusted OR: 5.76, 95% CI: 2.40-13.9) and short disease duration before starting BT with notable ALT elevation (adjusted OR: 1.10, 95% CI: 1.01-1.22). Benign ALT elevation is common within 3 months after starting BT (especially infliximab) and scarcely led to cessation of the treatment. AIH is a rare finding during the first year of BT.

The role of upper gastrointestinal endoscopy in the diagnosis of pediatric inflammatory bowel disease.

Upper gastrointestinal (UGI) tract involvement is frequently reported in pediatric Crohn disease (CD) and ulcerative colitis (UC). Aside from granulomas, most findings are nonspecific. The aims of this study were to review the prevalence of UGI tract findings in pediatric patients with CD or UC at diagnosis and to describe differences in endoscopic and histologic features. Patients with CD and UC aged 2 to 17 years diagnosed between 2000 and 2015 who had upper and lower endoscopy at diagnosis were randomly chosen from the BC Children's Hospital inflammatory bowel disease (IBD) registry. Pathology review of the UGI biopsy specimens was blinded to IBD diagnosis. Of the 198 patients, 102 with CD and 96 with UC were included, with a mean age of 11.7 years (range, 2.3-17 years). Patients with CD were more likely to have aphthous ulcers (20.4% vs 3.5%, P = .002) and erosions (16.3% vs 3.5%, P =.018), most commonly affecting the antrum. Macroscopically normal UGI endoscopy was present in 60% of patients. Microscopic disease was reported in 100% of patients with CD and 87% of patients with UC. In both groups, nonspecific inflammation was the most common finding. Chronic deep, superficial, and diffuse inflammation were more frequent among patients with CD than UC (42% vs 4%, P < .001; 60% vs 17%, P < .001; 50% vs 34%, P = .04, respectively). The UGI tract macroscopic changes were common in pediatric IBD, especially in CD. Despite macroscopically normal endoscopy, histologic abnormalities were frequent. Although chronic inflammation was more often reported in patients with CD, aside from granulomas there were no unique histologic abnormalities unique to CD.

Sexual health in adolescents with inflammatory bowel disease - The paediatric gastroenterologists' point of view.

Although sexual health (SH) impairment and sexually transmitted infections (STI) are occasionally encountered in patients with inflammatory bowel disease (IBD), paediatric gastroenterologists (PedGI) do not often discuss these issues. Literature about SH in the paediatric IBD population is limited. We aimed to assess PedGI knowledge and common practice related to sexual advice and STI workups in patients with IBD. A questionnaire comprising 25 questions addressing sexual activity in youth, SH, recommendations, and workup for STI in adolescents with IBD was sent to all registered PedGI in Israel. Fifty-two physicians completed the questionnaire (27 males,52%). Only 50% correctly predicted the mean age that Israeli youth start practicing sex. Seventy-five per cent responded that providers should discuss sexual activity with their patients, but only 19% do so, most often in response to a patient's query. Ninety six percent answered that they do not have enough knowledge about SH in IBD. Finally, only 2% obtain rectal swabs for STI in patients with refractory proctitis. Sexual issues and recommendations are not routinely discussed by the majority of PedGI in paediatric IBD clinics. Providers should obtain more knowledge in the field and initiate discussion of these issues with adolescent patients with IBD.

Acute pancreatitis in children with inflammatory bowel disease: Risk factors, clinical course, and prognosis.

To characterize the clinical course of acute pancreatitis (AP) in pediatric inflammatory bowel disease (IBD) patients compared to children with AP without IBD and to identify risk factors associated with AP among IBD patients. This retrospective, single-center study compared clinical characteristics of children (<19 years) with AP with and without concomitant IBD who were hospitalized 2005-2019. We also conducted a risk factor analysis of AP development in pediatric IBD. Sixty-eight (54% males) patients with 120 episodes of AP were admitted at a median age of 15.3 years. Thirteen patients (14 episodes) had a co-diagnosis of IBD, representing 4% of our IBD patient population. The AP-IBD patients presented with lower amylase levels compared to the non-IBD patients (160 [interquartile range, IQR: 83-231] vs. 418 [IQR: 176-874] U/L, p > 0.01), all had a mild pancreatitis, and none required invasive intervention. The presumed etiology for AP in all IBD patients was IBD-related: IBD flare-up in five, side effects of medications in two, and undetermined in seven. The only risk factor for AP development among IBD patients was IBD-associated arthritis (23% vs. 3% for IBD-non-AP, p = 0.04), while extracolonic Crohn's disease and induction therapy with nutrition were negative risk factors (15% vs. 51%, p = 0.05, and 8% vs. 44%, p = 0.04, respectively). Other parameters, including disease type and medications, were nonsignificant. The clinical course of AP in pediatric IBD patients is mild. Only IBD-associated arthritis emerged as a risk factor for the development of AP, while, unexpectedly, IBD medication did not.

Identification and validation of a blood- based diagnostic lipidomic signature of pediatric inflammatory bowel disease

Improved biomarkers are needed for pediatric inflammatory bowel disease. Here we identify a diagnostic lipidomic signature for pediatric inflammatory bowel disease by analyzing blood samples from a discovery cohort of incident treatment-naïve pediatric patients and validating findings in an independent inception cohort. The lipidomic signature comprising of only lactosyl ceramide (d18:1/16:0) and phosphatidylcholine (18:0p/22:6) improves the diagnostic prediction compared with high-sensitivity C-reactive protein. Adding high-sensitivity C-reactive protein to the signature does not improve its performance. In patients providing a stool sample, the diagnostic performance of the lipidomic signature and fecal calprotectin, a marker of gastrointestinal inflammation, does not substantially differ. Upon investigation in a third pediatric cohort, the findings of increased lactosyl ceramide (d18:1/16:0) and decreased phosphatidylcholine (18:0p/22:6) absolute concentrations are confirmed. Translation of the lipidomic signature into a scalable diagnostic blood test for pediatric inflammatory bowel disease has the potential to support clinical decision making.

Arterial structure and function in children with inflammatory bowel disease.

People with inflammatory bowel disease (IBD) have an increased risk of cardiovascular disease, including in younger adulthood. This may arise in part from chronic, systemic low-grade inflammation. The process of atherosclerosis may begin in childhood. We sought to determine whether pediatric IBD is associated with adverse changes in arterial structure and function as a marker of early increased cardiovascular risk. We performed a case-control study comparing children with IBD for a median disease duration of 2.49 (interquartile range 1.23, 4.38) years with healthy children. In a single visit, we collected baseline clinical and anthropometric data, and measured blood pressure, pulse wave velocity, carotid artery distensibility, and aortic and carotid intima-media thickness. High-sensitivity C-reactive protein and fasting lipids were measured. We enrolled 81 children with IBD (40 with Crohn's disease, 40 with ulcerative colitis, and 1 with unspecified IBD) and 82 control participants. After adjusting for age, sex, body mass index z-score, blood pressure, and low-density lipoprotein cholesterol, there was no difference in measures of arterial structure and function in children with IBD compared with controls, nor between those with Crohn's disease or ulcerative colitis. We did not show any differences in arterial structure and function in children with a history of IBD for less than 5 years compared with healthy controls. IBD diagnosed in childhood may provide a window of opportunity to actively reduce standard cardiovascular risk factors and improve future cardiovascular outcomes.

Landscape of TPMT and NUDT15 Pharmacogenetic Variation in a Cohort of Canadian Pediatric Inflammatory Bowel Disease Patients.

Patients with inflammatory bowel disease (IBD) exhibit considerable interindividual variability in medication response, highlighting the need for precision medicine approaches to optimize and tailor treatment. Pharmacogenetics (PGx) offers the ability to individualize dosing by examining genetic factors underlying the metabolism of medications such as thiopurines. Pharmacogenetic testing can identify individuals who may be at risk for thiopurine dose-dependent adverse reactions including myelosuppression. We aimed to evaluate PGx variation in genes supported by clinical guidelines that inform dosing of thiopurines and characterize differences in the distribution of actionable PGx variation among diverse ancestral groups. Pharmacogenetic variation in TPMT and NUDT15 was captured by genome-wide genotyping of 1083 pediatric IBD patients from a diverse Canadian cohort. Genetic ancestry was inferred using principal component analysis. The proportion of PGx variation and associated metabolizer status phenotypes was compared across 5 genetic ancestral groups within the cohort (Admixed American, African, East Asian, European, and South Asian) and to prior global estimates from corresponding populations. Collectively, 11% of the cohort was categorized as intermediate or poor metabolizers of thiopurines, which would warrant a significant dose reduction or selection of alternate therapy. Clinically actionable variation in TPMT was more prevalent in participants of European and Admixed American/Latino ancestry (8.7% and 7.5%, respectively), whereas variation in NUDT15 was more prevalent in participants of East Asian and Admixed American/Latino ancestry (16% and 15% respectively). These findings demonstrate the considerable interpopulation variability in PGx variation underlying thiopurine metabolism, which should be factored into testing diverse patient populations.

Effectiveness and Safety of Ustekinumab in Pediatric Ulcerative Colitis: A Multi-center Retrospective Study from the Pediatric IBD Porto Group of ESPGHAN.

Current data on ustekinumab therapy in children with ulcerative colitis (UC) or unclassified inflammatory bowel disease (IBDU) are limited. We aimed to evaluate the effectiveness and safety of ustekinumab in pediatric UC and IBDU. This multicenter retrospective study included 16 centers affiliated with the IBD Interest and Porto groups of ESPGHAN. Children with UC or IBDU treated with ustekinumab were enrolled. Demographic, clinical, laboratory, endoscopic, and imaging data as well as adverse events were recorded. Analyses were all based on the intention-to-treat principle. Fifty-eight children (39 UC and 19 IBDU, median age 14.5 [IQR 11.5-16.5] years) were included. All had failed biologic therapies, and 38 (66%) had failed two or more biologics. Corticosteroid-free clinical remission (CFR) was observed in 27 (47%), 33 (57%), and 37 (64%) children at 16, 26, and 52 weeks, respectively. Normalization of C-reactive protein and calprotectin <150μg/g were achieved in 60% and 52%, respectively, by 52 weeks. Endoscopic and radiologic remissions were reached in 8% and 23%, respectively. The main predictors of CFR were diagnosis of UC compared with IBDU (hazard ratio [HR] 2.2, 95% CI 1.03-4.85; p=0.041) and no prior vedolizumab therapy (HR 2.1, 95% CI 1.11-4.27; p=0.023). Ustekinumab serum levels were not associated with disease activity. Adverse events were recorded in six (10%) children, leading to discontinuation of the drug in three. Based on these findings, ustekinumab appears as an effective therapy for pediatric refractory UC and IBDU. The potential efficacy should be weighed against the risks of serious adverse events.

Transcultural adaptation and validation of IMPACT-III and IMPACT-III-P in Spanish families: a multicenter study from SEGHNP.

The SEGHNP versions of IMPACT-III and IMPACT-III-P are valid and reliable instruments for Spanish p-IBD families. • IMPACT-III and parent-proxy IMPACT-III (IMPACT-III-P) are useful questionnaires for assessing health-related quality of life (HRQoL) in pediatric inflammatory bowel disease (p-IBD) patients and their parents/caregivers and have been translated and validated in several countries. • To date, no transcultural adaptation and validation of these questionnaires have been published for Spanish patients with p-IBD and their families. • This is the first transcultural adaptation and validation of IMPACT-III and IMPACT-III-P for Spanish p-IBD families. • These are valid and reliable instruments for assessing HRQoL in Spanish families of patients with p-IBD.

STEP-CD study: ustekinumab use in paediatric Crohn's disease-a multicentre retrospective study from paediatric IBD Porto group of ESPGHAN.

Ustekinumab is an effective therapy for adult Crohn's disease (CD), but data in paediatric CD patients are scarce. The aim of the study was to describe the real-life effectiveness and safety of ustekinumab in paediatric CD. This is a multicentre review of children with Crohn's disease treated with ustekinumab. The aim of our study was to describe the effectiveness and safety of ustekinumab in paediatric real-life practice. This is a study of the Paediatric IBD (inflammatory bowel disease) Porto group of ESPGHAN. Corticosteroid (CS)- and exclusive enteral nutrition (EEN)-free remission, defined as weighted Paediatric Crohn's Disease Activity Index (wPCDAI) < 12.5, and physician global assessment (PGA) were determined at weeks 12 and 52. A total of 101 children were included at a median age of 15.4 years (IQR 12.7-17.2) with a median follow-up of 7.4 months (IQR 5.6-11.8). Ninety-nine percent had received prior anti-TNF, 63% ≥ 2 anti-TNFα therapies and 22% vedolizumab. Baseline median wPCDAI was 39 (IQR 25-57.5) (71 (70%) patients with moderate-severe activity). Weeks 12 and 52 CS- and EEN-free remission were both 40.5%. Clinical response at week 6, iv induction route and older age at onset of ustekinumab treatment were predictive factors associated with clinical remission at week 12. Seven minor adverse events probably related to ustekinumab were reported. One patient died from an unrelated cause. Conclusion: Our results suggest that ustekinumab is effective and safe in children with chronically active or refractory CD. What is Known: • Ustekinumab is an effective therapy for adult moderate to severe Crohn's disease (CD). • Off-label use of ustekinumab in children is increasing especially in anti-TNF refractory CD. What is New: • Is the largest cohort of real-world use of ustekinumab in paediatric CD to date. • Clinical response at week 6, iv induction and older age at onset of ustekinumab were predictive factors associated with clinical response at week 12.

Pediatric to Adult Transition in Inflammatory Bowel Disease: Consensus Guidelines for Australia and New Zealand.

The incidence of pediatric inflammatory bowel disease (IBD) is rising, and there is an increasing need to support adolescents when they transition to adult care. Evidence supports the use of a structured transition process but there is great variation across Australasia. The study aim was to develop evidence and expert opinion-based consensus statements to guide transitional care services in IBD. A modified UCLA-RAND methodology was employed to develop consensus statements. An IBD expert steering committee was formed and a systematic literature review was conducted to guide the drafting of consensus statements. A multidisciplinary group was formed comprising 16 participants (clinicians, nurses, surgeons, psychologists), who anonymously voted on the appropriateness and necessity of the consensus statements using Likert scales (1 = lowest, 9 = highest) with a median ≥7 required for inclusion. Patient support groups, including direct input from young people with IBD, informed the final recommendations. Fourteen consensus statements were devised with key recommendations including use of a structured transition program and transition coordinator, mental health and transition readiness assessment, key adolescent discussion topics, allied health involvement, age for transition, and recommendations for clinical communication and handover, with individualized patient considerations. Each statement reached median ≥8 for appropriateness, and ≥7 for necessity, in the first voting round, and the results were discussed in an online meeting to refine statements. A multidisciplinary group devised consensus statements to optimize pediatric to adult transitional care for adolescents with IBD. These guidelines should support improved and standardized delivery of IBD transitional care within Australasia.

Biomarkers predicting the effect of anti-TNF treatment in paediatric and adult inflammatory bowel disease.

Paediatric and adult inflammatory bowel disease (pIBD, aIBD) patients may lose response to anti-tumour necrosis factor (TNF) treatment within the first year. Adult-extrapolated weight-based dosing is incorrect in children, due to age-related pharmacokinetic differences. We investigated biomarkers for initial and maintenance of response to infliximab (IFX) or adalimumab (ADA), comparing pIBD and aIBD patients. In this prospective, observational study, pIBD (n = 24) and aIBD (n = 21) patients were included when initiating anti-TNF. Escalation from standard dosing and continued anti-TNF at 12 and 18 months were assessed. Biomarkers included clinical laboratory parameters, faecal calprotectin (FCP) and IFX trough levels (TLs). Plasma proteomics was performed in pIBD. During our study, treatment escalation (in clinical loss of response) occurred more common in pIBD versus aIBD (p = 0.02). We established that IFX therapy escalation in pIBD patients was not due to low infliximab levels. We identified 9 pro-inflammatory proteins that were elevated in patients losing response. Anti-TNF exposure-response relationship may be different in pIBD versus aIBD. No biomarkers for maintained response were identified, but 9 inflammatory proteins were of interest as potential predictors for loss of response in pIBD.

Fecal proteolytic profiling of pediatric inflammatory bowel disease: A pilot study.

Colonoscopy is the gold standard for diagnosing inflammatory bowel disease (IBD). However, this invasive procedure has a high burden for pediatric patients. Previous research has shown elevated fecal amino acid concentrations in children with IBD versus controls. We hypothesized that this finding could result from increased proteolytic activity. Therefore, the aim of this study was to investigate whether fecal protease-based profiling was able to discriminate between IBD and controls. Protease activity was measured in fecal samples from patients with IBD (Crohn's disease (CD) n = 19; ulcerative colitis (UC) n = 19) and non-IBD controls (n = 19) using a fluorescence resonance energy transfer (FRET)-peptide library. Receiver operating characteristic (ROC) curve analysis was used to determine the diagnostic value of each FRET-peptide substrate. Screening the FRET-peptide library revealed an increased total proteolytic activity (TPA), as well as degradation of specific FRET-peptides specifically in fecal samples from IBD patients. Based on level of significance (p < .001) and ROC curve analysis (AUC > 0.85), the fluorogenic substrates W-W, A-A, a-a, F-h, and H-y showed diagnostic potential for CD. The substrates W-W, a-a, T-t, G-v, and H-y showed diagnostic potential for UC based on significance (p < .001) and ROC analysis (AUC > 0.90). None of the FRET-peptide substrates used was able to differentiate between protease activity in fecal samples from CD versus UC. This study showed an increased fecal proteolytic activity in children with newly diagnosed, treatment-naïve, IBD. This could lead to the development of novel, noninvasive biomarkers for screening and diagnostic purposes.

Elucidating the Role of SYK in the Intestinal Epithelium

Background: Inflammatory Bowel Disease (IBD) involves chronic and recurring inflammation of the gastrointestinal tract. We identified several patients presenting with immune dysregulation and systemic inflammation, including inflammation of the gut. Analysis of Whole Exome Sequencing data from pediatric IBD patients has identified five rare protein coding Spleen Tyrosine Kinase (SYK) variants. Functional studies have demonstrated increased kinase activity implicating them in disease pathophysiology. While the role of SYK is well characterized in immune cells, it is not understood what role it plays in the intestinal epithelium. Aims: The primary aim of this project is to understand the role SYK plays in the intestinal epithelium, what molecular pathways it signals through, and how its dysregulation leads to intestinal disease. Methods: To understand SYKs role in the intestinal epithelium, a BioID screen was used to identify novel SYK interacting proteins. BioID was done with wild type SYK as well as the patient derived variants in HEK293 cells. BioID hits were validated using co-immunoprecipitation (CoIP) and proximity ligation assay (PLA). Further functional analysis was done in Caco2 cells, an intestinal epithelial cell model, with western blot, ELISA, and luciferase assays to assess the effect of SYK activity on downstream inflammatory pathways. Finally, we investigated the effect of small molecule kinase inhibitors to explore possible novel treatment options. Results: The BioID screen revealed several high confidence interactors, with dysregulated interactions in the patient variants. USP25, a ubiquitin specific peptidase that is widely expressed, including in the intestinal epithelium, was identified as one of the strongest hits based on peptide counts. The interaction was validated with CoIP and PLA, and further analysis showed SYK activation decreased USP25 protein levels by up to eight-fold. The secretion of the proinflammatory chemokine, IL-8, in response to lipopolysaccharide (LPS) was found to be almost twice as high in Caco2 cells with patient SYK variants relative to WT. Cells expressing the patient variants of SYK showed increased NFkB and AP1 levels, indicating increased inflammatory gene expression when stimulated with 100ng/mL LPS. NFkB was also active for longer in cells expressing the patient variant of SYK post stimulation, with WT cells returning to baseline in under half an hour, while the patient variant stayed in an inflamed state for 36 to 48 hours after LPS was removed. Conclusions: Increased SYK activity is associated with the degradation of USP25. USP25 is known to cleave ubiquitin off TNF receptor associated factors (TRAFs). TRAFs are activated downstream of innate immune receptors such as TLR4, and need to be ubiquitinated for activation. USP25, which is responsible for the deubiquitination of these TRAFs, acts as a negative regulator of these pathways. The hyperactive SYK variants degrade USP25 and impair the cells’ ability to switch off inflammatory signaling pathways, indicated by the cells elongated period in an inflamed state. This research is funded by grants from Canadian Institute for Health Research (CIHR) and the Leona M. and Harry B. Helmsley Charitable Trust. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.