I am a pediatric gastroenterologist and physician scientist, who has been devoted to inflammatory bowel disease (IBD) research since beginning medical training over 20 years ago. I am also Director of the Stanford Center for Pediatric IBD and Celiac Disease. I have expertise crossing mucosal immunology and epithelial biology, formal training and experience in clinical and translational investigation with human biospecimens, and direct insight regarding the important clinical challenges caring for children with complicated IBD. My translational research program focuses on how the immune system regulates epithelial function in chronic intestinal inflammation as it relates to IBD. My clinical research program has focused on optimization of anti-TNF therapy in pediatric IBD, and in particular acute severe ulcerative colitis (ASUC). My laboratory has demonstrated a protective role for IL33, a cytokine that induces type 2 cytokines from T cells an innate lymphoid cells (ILCs), in acute oxazolone colitis through preservation of epithelial goblet cells and barrier function. In line with this finding, we have also shown in a large prospective patient cohort that mucosal expression of type 2 and type 17 immune response genes distinguishes ulcerative colitis (UC) from colon-only Crohn’s disease, and that type 2 gene expression is associated with superior clinical outcome in pediatric UC. We have now developed an organoid-immune cell in vitro culture system to demonstrate the ILC2-dependent mechanism through which IL33 induces goblet cell differentiation in the intestinal epithelium. I led the multicenter study Anti-TNF for Refractory Colitis in Hospitalized Children (ARCH) Study, which aims to establish determinants of anti-TNF response in pediatric ASUC and currently Co-Chair the Crohn's & Colitis Foundations Cohort for Pediatric Translational and Clinical Research in IBD (CAPTURE IBD) and PRO-KIIDS Pediatric IBD clinical research network.
- Pediatric Gastroenterology
Director, Stanford Center for Pediatric IBD and Celiac Disease (2021 - Present)
Boards, Advisory Committees, Professional Organizations
Editorial Board, Gastroenterology (2021 - Present)
Chair, PRO-KIIDS Pediatric IBD Research Network, Crohn's & Colitis Foundation (2019 - Present)
Editorial Board, Inflammatory Bowel Diseases (2015 - Present)
Board Certification: American Board of Pediatrics, Pediatric Gastroenterology (2009)
Fellowship: Vanderbilt University Medical Center (2009) TN
Board Certification: American Board of Pediatrics, Pediatrics (2006)
Residency: Boston Childrens Hospital Pediatric Residency (2006) MA
MD, Harvard Medical School (2003)
Medical Education: Harvard Medical School (2003) MA
BS, Duke University, Biology (1999)
MSCI, Vanderbilt University School of Medicine, Clinical Investigation (2006)
MULTICENTER COHORT STUDY OF INFLIXIMAB PHARMACOKINETICS AND THERAPY RESPONSE IN PEDIATRIC ACUTE SEVERE ULCERATIVE COLITIS.
Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association
BACKGROUND AND AIMS: We aimed to model infliximab (IFX) pharmacokinetics (PK) in pediatric acute severe ulcerative colitis (ASUC) and assess the association between PK parameters, including drug exposure, and clinical response.METHODS: We studied a multicenter prospective cohort of hospitalized children initiating IFX for ASUC or IBD-unclassified. Serial IFX serum concentrations over 26 weeks were used to develop a PK model. We tested the association of PK parameter estimates with day 7 clinical response, week 8 clinical remission, week 26 corticosteroid-free clinical remission (CSF-CR) (using the Pediatric Ulcerative Colitis Activity Index) and colectomy-free survival.RESULTS: 38 participants received IFX (median initial dose 9.9 mg/kg). Day 7 clinical response, week 8 clinical remission, and week 26 CSF-CR occurred in 71%, 55%, and 43%, respectively. Albumin, C-reactive protein, white blood cell count, platelets, weight, and antibodies to IFX were significant covariates incorporated into a PK model. Week 26 non-remitters exhibited faster IFX clearance than remitters (P=.013). However, cumulative IFX exposure did not differ between clinical response groups. One (2.7%) and four (10.8%) participants underwent colectomy by week 26 and two years, respectively. Day 3 IFX clearance > .02 L/h was associated with colectomy (HR 58.2, 95% CI: 6.0-568.6, P < .001).CONCLUSIONS: At median higher-than-label IFX dosing for pediatric ASUC, baseline faster IFX CL was associated with colectomy and, at week 26, with lack of CSF-CR. IFX exposure was not predictive of clinical outcomes. Higher IFX dosing may sufficiently optimize early outcomes in pediatric ASUC. Larger studies are warranted to determine if sustained intensification can overcome rapid clearance and improve later outcomes.
View details for DOI 10.1016/j.cgh.2022.08.016
View details for PubMedID 36031093
Targeted Assessment of Mucosal Immune Gene Expression Predicts Clinical Outcomes in Children with Ulcerative Colitis.
Journal of Crohn's & colitis
We aimed to determine whether a targeted gene expression panel could predict clinical outcomes in pediatric UC and investigated putative pathogenic roles of predictive genes.313 rectal RNA samples from a cohort of newly diagnosed pediatric UC patients (PROTECT) were analyzed by a real-time PCR microfluidic array for expression of type 1, 2, and 17 inflammation genes. Associations between expression and clinical outcomes were assessed by logistic regression. Identified prognostic markers were further analyzed using existing RNA sequencing (RNA-seq) data sets and tissue immunostaining.IL13RA2 was associated with lower likelihood of corticosteroid-free remission (CSFR) on mesalamine at week 52 (P= .002). A model including IL13RA2 and only baseline clinical parameters was as accurate as an established clinical model, which requires week 4 remission status. RORC was associated with lower likelihood of colectomy by week 52. A model including RORC and PUCAI predicted colectomy by 52 weeks (AUC 0.71). Bulk RNA-seq identified IL13RA2 and RORC as hub genes within UC outcome-associated expression networks related to extracellular matrix and innate immune response, and lipid metabolism and microvillus assembly, respectively. Adult UC single-cell RNA-seq data revealed IL13RA2 and RORC co-expressed genes were localized to inflammatory fibroblasts and undifferentiated epithelial cells, respectively, which was supported by protein immunostaining.Targeted assessment of rectal mucosal immune gene expression predicts 52-week CSFR in treatment-naïve pediatric UC patients. Further exploration of IL-13Rɑ2 as a therapeutic target in UC, and future studies of the epithelial-specific role of RORC in UC pathogenesis are warranted.
View details for DOI 10.1093/ecco-jcc/jjac075
View details for PubMedID 35665804
Identification of Immunoglobulin G Autoantibody Against Malondialdehyde-Acetaldehyde Adduct as Novel Serological Biomarker for Ulcerative Colitis.
Clinical and translational gastroenterology
INTRODUCTION: Inflammatory bowel disease (IBD) is associated with immune responses with oxidative stress wherein high levels of malondialdehyde result in the formation of a highly stable and immunogenic malondialdehyde-acetaldehyde adduct (MAA). Thus, this study evaluated the status of MAA-adducts and anti-MAA antibody isotypes in IBD, and their potential as novel serologic biomarkers for differentiating ulcerative colitis (UC) from Crohn's disease (CD).METHODS: Levels of MAA-adduct and anti-MAA antibodies were examined in patients with IBD (171), non-IBD gastrointestinal diseases (77) and controls (83), from 2-independent cohorts using immunohistochemistry and enzyme-linked immunosorbent assay. Receiver operating characteristic curves and Youden cut-off index from logistic regression were used to determine the sensitivity and specificity.RESULTS: The MAA-adduct and blood immunoglobulin G (IgG) anti-MAA antibody levels were significantly elevated in IBD compared to non-IBD patients (P = 0.0008) or controls (P = 0.02). Interestingly, UC patients showed higher levels of IgG anti-MAA (P < 0.0001) than CD patients including those with colonic CD (P = 0.0067). Odds ratio by logistic regression analysis predicted stronger association of IgG anti-MAA antibody with UC than CD. Subsequent analysis showed that IgG anti-MAA antibody levels could accurately identify (P = 0.0004) UC in the adult cohort with sensitivity of (75.3%) and specificity of (71.4%), and area under the curve of 0.8072 (0.7121-0.9024). The pediatric cohort also showed area under the curve of 0.8801 (0.7988-0.9614) and precisely distinguished (P < 0.0001) UC with sensitivity (95.8%) and specificity (72.3%).DISCUSSION: Circulating IgG anti-MAA antibody levels can serve as novel, non-invasive, and highly sensitive test to identify UC patients, and possibly differentiate them from patients with CD.
View details for DOI 10.14309/ctg.0000000000000469
View details for PubMedID 35287144
Antibodies-to-infliximab accelerate clearance while dose intensification reverses immunogenicity and recaptures clinical response in paediatric Crohn's disease
ALIMENTARY PHARMACOLOGY & THERAPEUTICS
Antibodies to infliximab (ATI) are associated with secondary loss of response and increased risk for drug reactions. Limited studies have associated ATI with increased infliximab clearance.We assessed the impact of ATI on infliximab clearance and loss of response in an inception paediatric Crohn's disease cohort with 1-year follow-up.This multi-centre prospective cohort study collected peak and trough serum infliximab/ATI concentrations from 660 infusions (78 patients) during the first year of therapy. Clinicians were blinded to these research labs. The primary outcome was the difference in infliximab clearance between ATI-positive (ATI) and ATI-negative (no-ATI) patients. Secondary outcomes included pre-treatment predictors of ATI (including HLA-DQA1 genotyping). Clinical remission, loss of response and infliximab clearance were compared between pre-ATI, during ATI and following ATI resolution with MANOVA. Time to ATI was calculated by Cox proportional Hazards model.ATI were detected in 68% (53/78) patients with a median concentration of 76 ng/mL (range 23-1828). Maximum ATI concentration was <200 ng/mL in 73.6% (39/53). Median clearance in ATI patients was higher (with higher clearance if loss of response), compared to no-ATI patients (P < 0.001). Neutrophil CD64 ratio >6 and starting dose <7.5 mg/kg independently predicted ATI in multivariable regression, while HLA-DQA1*05 presence did not. Dose adjustment resolved ATI in 37.5% (12/32) patients with concomitant infliximab concentration and clearance recovery. A maximum ATI level of ≤99 ng/mL predicted ATI resolution (area under the receiver operating curve 0.80 [95% CI 0.64-0.96]).In this real-world cohort, ATI as low as 23 ng/mL impacted drug clearance. Our data suggest that dose optimisation for low-level ATI can improve infliximab clearance and prevent loss of response.
View details for DOI 10.1111/apt.16733
View details for Web of Science ID 000732588600001
View details for PubMedID 34935161
- New role for fatty acid receptor regulation of immune cells to control intestinal inflammation. Gastroenterology 2021
SLCO1B1 *15 allele is associated with methotrexate-induced nausea in pediatric patients with inflammatory bowel disease.
Clinical and translational science
Low-dose methotrexate (MTX) is an immunosuppressant used to treat inflammatory bowel disease (IBD). SLCO1B1 genetic variation has been associated with delayed MTX clearance and increased toxicity. The purpose of this study was to evaluate the association between SLCO1B1 genetic variation and MTX-induced nausea in children with IBD. We performed a single center retrospective chart analysis of 278 patients who were prescribed MTX for IBD. Two hundred two patients had banked DNA and were genotyped for three SLCO1B1 single nucleotide polymorphisms (SNPs; rs4149056, rs2306283, and rs11045819). Diplotypes were determined by combining the SNPs into *1, *4, *5, *14, *15, and *37 alleles. Incidence of nausea was abstracted from clinician notes. Prescriptions and demographics were extracted from the medical record. The cohort was 69.8% boys, 89.1% White, and 87.6% had a diagnosis of Crohn's disease with a mean age of 16.0 (± 3.8) years. MTX-induced nausea was noted in 34% of the cohort. MTX-induced nausea was associated with the number of reduced-function *15 alleles (p=0.034) and occurred 2.26 times more often in patients with at least one *15 allele who did not initiate MTX treatment with concomitant ondansetron (p=0.034). MTX-induced nausea was significantly independently associated with SLCO1B1 diplotype (p=0.006) after controlling for MTX dose group and concomitant ondansetron. Our data demonstrate that the SLCO1B1 *15 allele is associated with MTX-induced nausea in pediatric patients with IBD. Additionally, *15 allele carriers could benefit from a dose reduction of MTX to reduce exposure and treatment initiation with concomitant ondansetron to reduce nausea.
View details for DOI 10.1111/cts.13130
View details for PubMedID 34423897
The Promise of Patient-Derived Colon Organoids to Model Ulcerative Colitis.
Inflammatory bowel diseases
Physiologic, molecular, and genetic findings all point to impaired intestinal epithelial function as a key element in the multifactorial pathogenesis of ulcerative colitis (UC). The lack of epithelial-directed therapies is a conspicuous weakness of our UC therapeutic armamentarium. However, a critical barrier to new drug discovery is the lack of preclinical human models of UC. Patient tissue-derived colon epithelial organoids (colonoids) are primary epithelial stem cell-derived in vitro structures capable of self-organization and self-renewal that hold great promise as a human preclinical model for UC drug development. Several single and multi-tissue systems for colonoid culture have been developed, including 3-dimensional colonoids grown in a gelatinous extracellular matrix, 2-dimensional polarized monolayers, and colonoids on a chip that model luminal and blood flow and nutrient delivery. A small number of pioneering studies suggest that colonoids derived from UC patients retain some disease-related transcriptional and epigenetic changes, but they also raise questions regarding the persistence of inflammatory transcriptional programs in culture over time. Additional research is needed to fully characterize the extent to which and under what conditions colonoids accurately model disease-associated epithelial molecular and functional aberrations. With further advancement and standardization of colonoid culture methodology, colonoids will likely become an important tool for realizing precision medicine in UC.
View details for DOI 10.1093/ibd/izab161
View details for PubMedID 34251431
PIR-B Regulates CD4+ IL17a+ T-Cell Survival and Restricts T-Cell-Dependent Intestinal Inflammatory Responses.
Cellular and molecular gastroenterology and hepatology
BACKGROUND & AIMS: CD4+ T cells are regulated by activating and inhibitory cues, and dysregulation of these proper regulatory inputs predisposes these cells to aberrant inflammation and exacerbation of disease. We investigated the role of the inhibitory receptor paired immunoglobulin-like receptor B (PIR-B) in the regulation of the CD4+ T-cell inflammatory response and exacerbation of the colitic phenotype.METHODS: We used Il10-/- spontaneous and CD4+CD45RBhi T-cell transfer models of colitis with PIR-B-deficient (Pirb-/-) mice. Flow cytometry, Western blot, and RNA sequencing analysis was performed on wild-type and Pirb-/- CD4+ T cells. In silico analyses were performed on RNA sequencing data set of ileal biopsy samples from pediatric CD and non-inflammatory bowel disease patients and sorted human memory CD4+ T cells.RESULTS: We identified PIR-B expression on memory CD4+ interleukin (IL)17a+ cells. We show that PIR-B regulates CD4+ T-helper 17 cell (Th17)-dependent chronic intestinal inflammatory responses and the development of colitis. Mechanistically, we show that the PIR-B-SHP-1/2 axis tempers mammalian target of rapamycin complex 1 signaling and mammalian target of rapamycin complex 1-dependent caspase-3/7 apoptosis, resulting in CD4+ IL17a+ cell survival. In silico analyses showed enrichment of transcriptional signatures for Th17 cells (RORC, RORA, and IL17A) and tissue resident memory (HOBIT, IL7R, and BLIMP1) networks in PIR-B+ murine CD4+ T cells and human CD4+ T cells that express the human homologue LILRB3. High levels of LILRB3 expression were associated strongly with mucosal injury and a proinflammatory Th17 signature, and this signature was restricted to a treatment-naive, severe pediatric CD population.CONCLUSIONS: Our findings show an intrinsic role for PIR-B/LILRB3 in the regulation of CD4+ IL17a+ T-cell pathogenic memory responses.
View details for DOI 10.1016/j.jcmgh.2021.06.013
View details for PubMedID 34242819
Achieving Target Infliximab Drug Concentrations Improves Blood and Fecal Neutrophil Biomarkers in Crohn's Disease
INFLAMMATORY BOWEL DISEASES
2021; 27 (7): 1045-1051
The neutrophil fecal biomarkers, calprotectin (FCP) and lactoferrin (LCT), and peripheral blood neutrophil CD64 surface receptor (nCD64) are biomarkers for mucosal inflammation in inflammatory bowel disease (IBD). Although FCP has been evaluated as a biomarker for mucosal healing, cut points for LCT and nCD64 are less known. We aimed to identify the cut points for LCT and nCD64 that were associated with FCP remission, with a secondary aim to evaluate the relationship between biochemical outcomes and infliximab (IFX) trough concentrations.We analyzed FCP, LCT, and nCD64 before and after IFX induction in a pediatric Crohn's disease (CD) cohort study. Week-14 FCP biomarker remission was defined as FCP <250 µg/g, with clinical response defined as a weighted Pediatric Crohn's Disease Activity Index <12.5 or Δ>17.5 improvement. Predictive outcomes were calculated by receiver operating characteristics (ROCs).Among 56 CD patients, ROC analysis identified an infusion 4 LCT <8.06 (area under the receiver operator characteristics [AUROC], 0.934, P < 0.001) and nCD64 <6.12 (AUROC, 0.76, P = 0.02) as the ideal cut points for week-14 FCP biomarker remission. End of induction IFX-trough of >9.4 µg/mL (AUROC, 0.799, P = 0.002) and >11.5 µg/mL (AUROC, 0.835, P = 0.003) were associated with a FCP <250 and FCP <100, respectively. We found patients achieving end of induction trough >5 µg/mL had a median FCP improvement (dose 1 to dose 4) of 90% compared with a median of 35% with levels <5 µg/mL (P = 0.024) with a similar median reduction in nCD64 (48% vs 20%, P = 0.031).This study establishes cut points in neutrophil stool and blood biomarkers for both biochemical remission and therapeutic trough levels following induction therapy. Further studies that evaluate pharmacodynamic biomarker targets for endoscopic and histologic healing are warranted.
View details for DOI 10.1093/ibd/izaa241
View details for Web of Science ID 000670937700013
View details for PubMedID 32944769
View details for PubMedCentralID PMC8205636
IL-33 is produced by colon fibroblasts and differentially regulated in acute and chronic murine colitis
2021; 11 (1): 9575
IL-33 is upregulated in ulcerative colitis and has a protective role in chemically-induced acute murine colitis. We aimed to determine whether IL-33 influences Il10-/- chronic colitis and its cellular source in health and during colitis. Il10-/-Il33-/- and Il10-/-Il33+/+ littermates developed colitis of similar severity. Colon Il33 was induced in WT and Il10-/- mice exposed to DSS, but not in unchallenged Il10-/- mice with colitis. Il33-citrine reporter mice showed that Il33-citrine colocalized with α-smooth muscle actin+ myofibroblasts and vimentin+ fibroblasts in WT mice. Citrine+CD74+CD90hi inflammatory fibroblasts were increased with DSS treatment. IL-1β induced Il33 expression in colon myofibroblasts, but colon Il33 expression did not differ between DSS-treated WT and Il1r1-/- mice. In conclusion, deficiency of IL-33 does not alter the severity of chronic colitis in Il10-/- mice. Induction of Il33 upon DSS exposure in WT and Il10-/- mice, but not in unchallenged Il10-/- mice, suggests epithelial injury induces colon IL-33. Fibroblasts are the primary colonic source of IL-33 and IL-33-expressing CD90hiCD74+ fibroblasts are increased during DSS-induced colitis. IL-1β induces Il33 in colon myofibroblasts in vitro, but signaling through the IL-1R1 is not necessary for induction of IL-33 in DSS-induced colitis.
View details for DOI 10.1038/s41598-021-89119-1
View details for Web of Science ID 000656453000020
View details for PubMedID 33953267
View details for PubMedCentralID PMC8100152
Quality Improvement Methodology Optimizes Infliximab Levels in Pediatric Patients with Inflammatory Bowel Disease.
Pediatric quality & safety
2021; 6 (3): e400
Achieving and maintaining target serum trough infliximab levels improves outcomes in children and young adults with inflammatory bowel disease. Our goal was to improve adherence to an infliximab therapy guideline. The primary aim was to increase the percentage of patients with infliximab levels ≥5 mug/mL and results checked in the last 12 months from 73% to ≥80% from July 2017 to January 2018.Methods: We participated in Intermediate Improvement Science Series, a course at Cincinnati Children's Hospital Medical Center designed to catalyze change using quality improvement methodology. We implemented interventions through plan-do-study-act cycles. Our outcome measure was balanced by 2 process measures to determine what actions impacted improvement. These measures included the percentage of infusion plans revised in response to a drug level <5 mug/mL and the proportion of plans for which a follow-up drug level was ordered.Results: We increased the percentage of infusion plans revised before the next infusion from 63% to 87% and the percentage of plans that had an appropriate drug level recheck from 61% to 83% from July 2017 to January 2018. We increased the percentage of patients with an infliximab level >5 mug/mL, and results checked in the last 12 months, from 73% to 80%.Conclusions: Quality improvement methodology was effective in improving provider adherence to infliximab therapeutic drug monitoring guidelines. Improvement in adherence to guidelines directly improved the percentage of patients achieving target infliximab levels at any time during infliximab therapy.
View details for DOI 10.1097/pq9.0000000000000400
View details for PubMedID 33977189
Effect of a Practice-wide Anti-TNF Proactive Therapeutic Drug Monitoring Program on Outcomes in Pediatric Patients with Inflammatory Bowel Disease
INFLAMMATORY BOWEL DISEASES
2021; 27 (4): 482-492
Reports on the feasibility and effectiveness of translating proactive, antitumor necrosis factor (TNF) therapeutic drug monitoring (TDM) for inflammatory bowel disease into practice-wide quality improvement (QI) are lacking. We aimed to determine whether a TDM QI program improved outcomes at a large academic pediatric gastroenterology practice.We instituted local anti-TNF TDM practice guidelines to proactively monitor and optimize drug levels (goal >5 μg/mL). We conducted a retrospective single-center cohort analysis of patient outcomes before (pre-TDM) and after (post-TDM) guideline institution and assessed the independent effect by multivariable regression. Primary outcome was sustained clinical remission (SCR22-52), defined as physician global assessment (PGA) of inactive from 22 to 52 weeks and off corticosteroids at 52 weeks.We identified 108 pre-TDM and 206 post-TDM patients. The SCR22-52 was achieved in 42% of pre-TDM and 59% of post-TDM patients (risk difference, 17.6%; 95% CI, 5.4-29%; P = 0.004). The post-TDM group had an increased adjusted odds of achieving SCR22-52 (odds ratio, 2.03; 95% CI, 1.27-3.26; P = 0.003). The adjusted risk of developing high titer antidrug antibodies (ADAs) was lower in the post-TDM group (hazard ratio, 0.18; 95% CI, 0.09-0.35; P < 0.001). Although the risk of anti-TNF cessation for any reason was not significantly different, there was a lower adjusted risk of cessation related to any detectable ADA in the post-TDM group (hazard ratio, 0.45; 95% CI, 0.26-0.77; P = 0.003).A practice-wide proactive anti-TNF TDM QI program improved key clinical outcomes at our institution, including sustained clinical remission, incidence of high titer ADA, and anti-TNF cessation related to ADA.
View details for DOI 10.1093/ibd/izaa102
View details for Web of Science ID 000637281600012
View details for PubMedID 32448898
View details for PubMedCentralID PMC7957222
Favorable Outcomes and Anti-TNF Durability After Addition of an Immunomodulator for Anti-Drug Antibodies in Pediatric IBD Patients
INFLAMMATORY BOWEL DISEASES
2021; 27 (4): 507-515
Anti-drug antibodies (ADAs) to anti-tumor necrosis factor alpha (anti-TNF) drugs are associated with increased drug clearance and loss of response. We aimed to assess the effectiveness of starting an immunomodulator (IM) drug in patients with newly detected ADAs on anti-TNF monotherapy.We reviewed the medical records of pediatric patients with inflammatory bowel disease on infliximab or adalimumab monotherapy with first-time detection of significant ADAs between 2014 and 2018. Patients who started an IM within 3 months of ADA detection were compared with those who did not (No-IM). Outcomes included steroid-free clinical and biochemical remission on the same anti-TNF , anti-TNF durability, and ADA reversal.We identified 89 patients with ADAs: 30 IM patients and 59 No-IM patients. The initial anti-TNF was stopped shortly after ADA detection in 36% of the No-IM patients vs none of the IM patients, driving longer survival on the initial anti-TNF in the IM group (P = 0.005). At 12 months, steroid-free clinical and biochemical remission on the same anti-TNF occurred in 53.9% of the IM group vs 26.8% in the No-IM group (P = 0.025). Drug levels rose higher (P = 0.003) and ADA levels fell farther (P = 0.037) in the IM group than in the No-IM group. Baseline ADA level predicted ADA reversal in the No-IM patients with an area under the receiver operating characteristic of 0.79 (P = 0.006). An ADA level <329 ng/mL had a 76.2% sensitivity and an 83.3% specificity for ADA reversal without IM.Pediatric patients with inflammatory bowel disease on anti-TNF monotherapy who started an IM for significant ADA levels exhibited longer anti-TNF durability and a higher likelihood of steroid-free clinical and biochemical remission on the same anti-TNF. Patients not treated with an IM were unlikely to reverse ADAs >329 ng/mL.
View details for DOI 10.1093/ibd/izaa108
View details for Web of Science ID 000637281600015
View details for PubMedID 32426829
View details for PubMedCentralID PMC7957223
Colonic Epithelial-Derived Selenoprotein P Is the Source for Antioxidant-Mediated Protection in Colitis-Associated Cancer
2021; 160 (5): 1694-+
Patients with inflammatory bowel disease (IBD) demonstrate nutritional selenium deficiencies and are at greater risk of developing colon cancer. Previously, we determined that global reduction of the secreted antioxidant selenium-containing protein, selenoprotein P (SELENOP), substantially increased tumor development in an experimental colitis-associated cancer (CAC) model. We next sought to delineate tissue-specific contributions of SELENOP to intestinal inflammatory carcinogenesis and define clinical context.Selenop floxed mice crossed with Cre driver lines to delete Selenop from the liver, myeloid lineages, or intestinal epithelium were placed on an azoxymethane/dextran sodium sulfate experimental CAC protocol. SELENOP loss was assessed in human ulcerative colitis (UC) organoids, and expression was queried in human and adult UC samples.Although large sources of SELENOP, both liver- and myeloid-specific Selenop deletion failed to modify azoxymethane/dextran sodium sulfate-mediated tumorigenesis. Instead, epithelial-specific deletion increased CAC tumorigenesis, likely due to elevated oxidative stress with a resulting increase in genomic instability and augmented tumor initiation. SELENOP was down-regulated in UC colon biopsies and levels were inversely correlated with endoscopic disease severity and tissue S100A8 (calprotectin) gene expression.Although global selenium status is typically assessed by measuring liver-derived plasma SELENOP levels, our results indicate that the peripheral SELENOP pool is dispensable for CAC. Colonic epithelial SELENOP is the main contributor to local antioxidant capabilities. Thus, colonic SELENOP is the most informative means to assess selenium levels and activity in IBD patients and may serve as a novel biomarker for UC disease severity and identify patients most predisposed to CAC development.
View details for DOI 10.1053/j.gastro.2020.12.059
View details for Web of Science ID 000637453900035
View details for PubMedID 33388316
View details for PubMedCentralID PMC8035252
Predicting Therapeutic Response in Pediatric Ulcerative Colitis-A Journey Towards Precision Medicine
FRONTIERS IN PEDIATRICS
2021; 9: 634739
Ulcerative colitis (UC) is a disabling disease, characterized by chronic inflammation of the colon, with a rising prevalence worldwide in the pediatric age group. Although UC presents in children with varying severity, disease extent, and comorbidities, initial treatment is essentially uniform, consisting of 5-aminosalicylate drugs with corticosteroid induction for those with moderately to severely active disease. With the advent of anti-tumor necrosis factor (TNF) biologic therapy and several new biologics and small-molecule drugs for UC, precision medicine approaches to treatment are needed to more rapidly achieve sustained remission, restore quality of life, normalize development, and limit exposure to toxic corticosteroids in children with UC. Here, we review available data on clinical, biochemical, histopathologic, and molecular predictors of treatment response in UC. We also address known predictors and special treatment considerations in specific relevant scenarios such as very-early-onset UC, acute severe UC, ileal pouch anal anastomosis, and UC with concomitant primary sclerosing cholangitis. The review concludes with a prediction of how machine learning will integrate multimodal patient data to bring precision medicine to the bedside of children with UC in the future.
View details for DOI 10.3389/fped.2021.634739
View details for Web of Science ID 000624511300001
View details for PubMedID 33681110
View details for PubMedCentralID PMC7925616
Sprouty2 limits intestinal tuft and goblet cell numbers through GSK3 beta-mediated restriction of epithelial IL-33
2021; 12 (1): 836
Dynamic regulation of intestinal cell differentiation is crucial for both homeostasis and the response to injury or inflammation. Sprouty2, an intracellular signaling regulator, controls pathways including PI3K and MAPKs that are implicated in differentiation and are dysregulated in inflammatory bowel disease. Here, we ask whether Sprouty2 controls secretory cell differentiation and the response to colitis. We report that colonic epithelial Sprouty2 deletion leads to expanded tuft and goblet cell populations. Sprouty2 loss induces PI3K/Akt signaling, leading to GSK3β inhibition and epithelial interleukin (IL)-33 expression. In vivo, this results in increased stromal IL-13+ cells. IL-13 in turn induces tuft and goblet cell expansion in vitro and in vivo. Sprouty2 is downregulated by acute inflammation; this appears to be a protective response, as VillinCre;Sprouty2F/F mice are resistant to DSS colitis. In contrast, Sprouty2 is elevated in chronic colitis and in colons of inflammatory bowel disease patients, suggesting that this protective epithelial-stromal signaling mechanism is lost in disease.
View details for DOI 10.1038/s41467-021-21113-7
View details for Web of Science ID 000617500200009
View details for PubMedID 33547321
View details for PubMedCentralID PMC7864916
Real-World Infliximab Pharmacokinetic Study Informs an Electronic Health Record-Embedded Dashboard to Guide Precision Dosing in Children with Crohn's Disease
CLINICAL PHARMACOLOGY & THERAPEUTICS
2021; 109 (6): 1639-1647
Standard-of-care infliximab dosing regimens were developed prior to the routine use of therapeutic drug monitoring and identification of target concentrations. Not surprisingly, subtherapeutic infliximab concentrations in pediatric Crohn's disease (CD) are common. The primary aim was to conduct a real-world pharmacokinetic (PK) evaluation to discover blood biomarkers of rapid clearance, identify exposure targets, and a secondary aim to translate PK modeling to the clinic. In a multicenter observational study, 671 peak and trough infliximab concentrations from 78 patients with CD were analyzed with a drug-tolerant assay (Esoterix; LabCorp, Calabasas, CA). Individual area under the curve (AUC) estimates were generated as a measure of drug exposure over time. Population PK modeling (nonlinear mixed-effect modeling) identified serum albumin, antibody to infliximab, erythrocyte sedimentation rate (ESR), and neutrophil CD64 as biomarkers for drug clearance. Week 14 and week 52 biochemical remitters (fecal calprotectin < 250 µg/g) had higher infliximab exposure (AUC) throughout induction. The optimal infliximab AUC target during induction for week 14 biochemical remission was 79,348 µg*h/mL (area under the receiver operating characteristic curve (AUROC) 0.77, [0.63-0.90], 85.7% sensitive, and 64.3% specific) with those exceeding the AUC target more likely to achieve a surgery-free week 52 biochemical remission (OR 4.3, [1.2-14.6]). Pretreatment predictors for subtherapeutic week 14 AUC included neutrophil CD64 > 6 (OR 4.5, [1.4-17.8]), ESR > 30 mm/h (OR 3.8, [1.4-11]), age < 10 years old (OR 4.2, [1.2-20]), and weight < 30 kg (OR 6.6, [2.1-25]). We created a decision-support PK dashboard with an iterative process and embedded the modeling program within the electronic health record. Model-informed precision dosing guided by real-world PKs is now available at the bedside in real-time.
View details for DOI 10.1002/cpt.2148
View details for Web of Science ID 000605586500001
View details for PubMedID 33354765
View details for PubMedCentralID PMC8159860
Vedolizumab Experience in Children and Adolescents with Inflammatory Bowel Disease: A Multicenter Observational Study
Crohn's & Colitis 360
View details for DOI 10.1093/crocol/otab039
- Could a Small Population of Epithelial Cells Get "Tuft" With Crohn 's Disease? GASTROENTEROLOGY 2020; 159 (6): 2025-2027
A Micro-longitudinal Approach to Measuring Medication Adherence in Pediatric Inflammatory Bowel Diseases
JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION
2020; 71 (3): 366-370
Measuring medication adherence in pediatric inflammatory bowel diseases (IBD) is challenging because of complexities in personalized treatment regimens and increased use of biologic mono- and combination therapy. Objective measurement of adherence via electronic monitoring is the gold standard; however, it is not useful for daily monitoring when multiple medication formulations (eg, pills, injections, infusions) as well as vitamins/supplements are prescribed. Although validated subjective measures are available, they are not designed for daily use and do not capture day-to-day variation in adherence. In the following article, a new approach to measuring adherence regardless of a patient's specific medication regimen is presented. Utilizing a micro-longitudinal design, 30 days of daily self-reported medication adherence data was collected from youth with IBD via text message. Results reflect mean adherence rates from studies utilizing pill counts and electronic monitoring, suggesting promise for the use of self-reported daily diaries to assess medication adherence in pediatric IBD.
View details for DOI 10.1097/MPG.0000000000002778
View details for Web of Science ID 000570130600019
View details for PubMedID 32404759
View details for PubMedCentralID PMC8025293
Pediatric Patient With Ulcerative Colitis-Associated Bronchiectasis
ACG CASE REPORTS JOURNAL
2020; 7 (4): e00365
We report a unique case of ulcerative colitis-associated bronchiectasis in a pediatric patient 6 years after colectomy. The patient presented with a chronic cough and had a computed tomography demonstrating bronchiectasis. She was treated with sputum expectoration (airway clearance) via chest physiotherapy and pulse-dose steroids with a prolonged oral taper. Her initial response was excellent; however, she experienced a recurrence of symptoms with de-escalation of airway clearance. Pulmonary extraintestinal manifestations of inflammatory bowel disease are most often diagnosed later in life. Both the severity of this patient's presentation and her age are unique to this case.
View details for DOI 10.14309/crj.0000000000000365
View details for Web of Science ID 000588330100010
View details for PubMedID 32548193
View details for PubMedCentralID PMC7224709
Improved Population Pharmacokinetic Model for Predicting Optimized Infliximab Exposure in Pediatric Inflammatory Bowel Disease
INFLAMMATORY BOWEL DISEASES
2020; 26 (3): 429-439
Many pediatric patients with inflammatory bowel disease (IBD) lose response to infliximab (IFX) within the first year, and achieving a minimal target IFX trough concentration is associated with higher remission rates and longer durability. Population pharmacokinetic (PK) modeling can predict trough concentrations for individualized dosing. The object of this study was to refine a population PK model that accurately predicts individual IFX exposure during maintenance therapy using longitudinal real-practice data.We exported data from the electronic health records of pediatric patients with IBD treated with originator IFX at a single center between January 2011 and March 2017. Subjects were divided into discovery and validation cohorts. A population PK model was built and then validated.We identified 228 pediatric patients with IBD who received IFX and had at least 1 drug concentration measured, including 135 and 93 patients in the discovery and validation cohorts, respectively. Weight, albumin, antibodies to IFX (ATI) detected by a drug-tolerant assay, and erythrocyte sedimentation rate (ESR) were identified as covariates significantly associated with IFX clearance and incorporated into the model. The model exhibited high accuracy for predicting target IFX trough concentrations with an area under the receiver operating characteristic curve (AUROC) of 0.86 (95% confidence interval [CI], 0.81-0.91) for population-based predictions without prior drug-level input. Accuracy increased further for individual-based predictions when prior drug levels were known, with an AUROC of 0.93 (95% CI, 0.90-0.97).A population PK model utilizing weight, albumin, ordinal drug-tolerant ATI, and ESR accurately predicts IFX trough concentrations during maintenance therapy in real-practice pediatric patients with IBD. This model, which incorporates dynamic clinical information, could be used for individualized dosing decisions to increase response durability.
View details for DOI 10.1093/ibd/izz143
View details for Web of Science ID 000515114000015
View details for PubMedID 31287855
View details for PubMedCentralID PMC7171445
Elevated Pretreatment Plasma Oncostatin M Is Associated With Poor Biochemical Response to Infliximab.
Crohn's & colitis 360
2019; 1 (3): otz026
Background: We hypothesized that elevations of plasma Oncostatin M (OSM) would be associated with infliximab nonresponse.Methods: Plasma OSM was measured in Crohn disease patients pre-infliximab with biochemical response (>50% reduction in fecal calprotectin) as the primary outcome.Results: The median OSM in biochemical responders was 86 (69-148) pg/mL compared with 166 (74-1766) pg/mL in nonresponders (P = 0.03). Plasma OSM > 143.5 pg/mL was 71% sensitive and 78% specific for biochemical nonresponse (area under the curve 0.71). Early biochemical nonremission was also associated with an elevated neutrophil CD64 expression (odds ratio 8.9, P = 0.011).Conclusions: Elevated preinfliximab plasma OSM and nCD64 surface expression were both associated with poor biochemical outcomes.
View details for DOI 10.1093/crocol/otz026
View details for PubMedID 31667468
Development of Infliximab Target Concentrations During Induction in Pediatric Crohn Disease Patients
JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION
2019; 69 (1): 68-74
Subtherapeutic drug concentrations contribute to both primary and secondary nonresponse to infliximab in children with Crohn disease (CD). The aim of this study was to evaluate treatment outcomes and infliximab concentrations at infusions 2 and 3 with an objective to establish infliximab targets during induction for primary responders.Single-center, prospective cohort of anti- tumor necrosis factor-alpha naïve CD patients younger than 22 years starting infliximab. Clinical response was defined with the weighted pediatric CD activity index at the fourth infusion. Rates of biological response (>50% improvement in fecal calprotectin) and maintenance concentrations ≥5 μg/mL were secondary outcomes.We enrolled 72 patients with CD with 70 of 72 receiving infliximab monotherapy. Clinical response, biological response, and start of maintenance concentrations ≥5 μg/mL were achieved in 64%, 54%, and 22%, respectively. The median (interquartile range) infliximab concentrations at infusion 2 and 3 in clinical responders were 27.8 μg/mL (19.5-40) and 14 μg/mL (8.3-24) compared to 18.8 μg/mL (9.1-23, P < 0.001) and 7.8 μg/mL (4-13.2, P < 0.01) in nonresponders. Receiver operating characteristic analysis determined that an infliximab concentration ≥15.9 μg/mL at infusion 3 was associated with clinical response (area under the curve [AUC] 0.73), whereas an infusion 3 level ≥18 μg/mL was associated with a start of maintenance concentration >5 μg/mL (AUC 0.85). Independent predictors for infusion 3 levels <18 μg/mL included pretreatment prednisone, low body mass index, elevated erythrocyte sedimentation rate and C-reactive protein, hypoalbuminemia, and an infusion 2 infliximab level <29 μg/mL.We found that infusion 2 (≥29 μg/mL) and infusion 3 (≥18 μg/mL) infliximab concentrations were strongly associated with improved early outcomes and higher first maintenance dose levels.
View details for DOI 10.1097/MPG.0000000000002304
View details for Web of Science ID 000501132000018
View details for PubMedID 31232885
View details for PubMedCentralID PMC6607916
IL-33 Induces Murine Intestinal Goblet Cell Differentiation Indirectly via Innate Lymphoid Cell IL-13 Secretion
JOURNAL OF IMMUNOLOGY
2019; 202 (2): 598-607
Regulation of the intestinal mucus layer by goblet cells is important for preventing inflammation and controlling infection. IL-33, a cytokine upregulated in inflammatory bowel disease and helminth infection, induces intestinal goblet cells, but the mechanism remains unclear. Enteroids are three-dimensional structures of primary small intestinal epithelial cells that contain all differentiated intestinal epithelial cell types. We developed an enteroid-immune cell coculture model to determine the mechanism through which IL-33 affects intestinal goblet cell differentiation. We report that IL-33 does not directly induce goblet cell differentiation in murine enteroids; however, IL-13, a cytokine induced by IL-33, markedly induces goblet cells and gene expression consistent with goblet cell differentiation. When enteroids are cocultured with CD90+ mesenteric lymph node cells from IL-33-treated mice, IL-33 then induces IL-13 secretion by group 2 innate lymphoid cells and enteroid gene expression consistent with goblet cell differentiation. In cocultures, IL-33-induced Muc2 expression is dependent on enteroid Il4ra expression, demonstrating a requirement for IL-13 signaling in epithelial cells. In vivo, IL-33-induced intestinal goblet cell hyperplasia is dependent on IL-13. These studies demonstrate that IL-33 induces intestinal goblet cell differentiation not through direct action on epithelial cells but indirectly through IL-13 production by goup 2 innate lymphoid cells.
View details for DOI 10.4049/jimmunol.1800292
View details for Web of Science ID 000455041800030
View details for PubMedID 30530480
View details for PubMedCentralID PMC6324976
Ulcerative colitis mucosal transcriptomes reveal mitochondriopathy and personalized mechanisms underlying disease severity and treatment response
2019; 10: 38
Molecular mechanisms driving disease course and response to therapy in ulcerative colitis (UC) are not well understood. Here, we use RNAseq to define pre-treatment rectal gene expression, and fecal microbiota profiles, in 206 pediatric UC patients receiving standardised therapy. We validate our key findings in adult and paediatric UC cohorts of 408 participants. We observe a marked suppression of mitochondrial genes and function across cohorts in active UC, and that increasing disease severity is notable for enrichment of adenoma/adenocarcinoma and innate immune genes. A subset of severity genes improves prediction of corticosteroid-induced remission in the discovery cohort; this gene signature is also associated with response to anti-TNFα and anti-α4β7 integrin in adults. The severity and therapeutic response gene signatures were in turn associated with shifts in microbes previously implicated in mucosal homeostasis. Our data provide insights into UC pathogenesis, and may prioritise future therapies for nonresponders to current approaches.
View details for DOI 10.1038/s41467-018-07841-3
View details for Web of Science ID 000454757200003
View details for PubMedID 30604764
View details for PubMedCentralID PMC6318335
Contemporary Medical Management of Acute Severe Ulcerative Colitis
INFLAMMATORY BOWEL DISEASES
2019; 25 (1): 56-66
Acute severe ulcerative colitis is a medical emergency that requires prompt recognition, evaluation, and intervention. Patients require hospital admission with laboratory, radiographic, and endoscopic evaluation with initiation of corticosteroid treatment. Despite early intervention, many patients require salvage medical therapy, with some progressing to colectomy. Here we review important concepts and recent advances in the evaluation and medical management of adult and pediatric patients with acute severe ulcerative colitis.
View details for DOI 10.1093/ibd/izy208
View details for Web of Science ID 000462579400006
View details for PubMedID 29889235
View details for PubMedCentralID PMC6290785
Challenges in IBD Research: Preclinical Human IBD Mechanisms.
Inflammatory bowel diseases
2019; 25 (Suppl 2): S5-S12
Preclinical human IBD mechanisms is part of five focus areas of the Challenges in IBD research document, which also include environmental triggers, novel technologies, precision medicine and pragmatic clinical research. The Challenges in IBD research document provides a comprehensive overview of current gaps in inflammatory bowel diseases (IBD) research and delivers actionable approaches to address them. It is the result of a multidisciplinary input from scientists, clinicians, patients, and funders, and represents a valuable resource for patient centric research prioritization. In particular, the preclinical human IBD mechanisms manuscript is focused on highlighting the main research gaps in the pathophysiological understanding of human IBD. These research gap areas include: 1) triggers of immune responses; 2) intestinal epithelial homeostasis and wound repair; 3) age-specific pathophysiology; 4) disease complications; 5) heterogeneous response to treatments; and 6) determination of disease location. As an approach to address these research gaps, the prioritization of reverse translation studies is proposed in which clinical observations are the foundation for experimental IBD research in the lab, and for the identification of new therapeutic targets and biomarkers. The use of human samples in validating basic research findings and development of precision medicine solutions is also proposed. This prioritization aims to put emphasis on relevant biochemical pathways and humanized in vitro and in vivo models that extrapolate meaningfully to human IBD, to eventually yield first-in-class and effective therapies.
View details for DOI 10.1093/ibd/izz075
View details for PubMedID 31095706
Microbiota-sensitive epigenetic signature predicts inflammation in Crohn's disease
2018; 3 (18)
Altered response to the intestinal microbiota strongly associates with inflammatory bowel disease (IBD); however, how commensal microbial cues are integrated by the host during the pathogenesis of IBD is not understood. Epigenetics represents a potential mechanism that could enable intestinal microbes to modulate transcriptional output during the development of IBD. Here, we reveal a histone methylation signature of intestinal epithelial cells isolated from the terminal ilea of newly diagnosed pediatric IBD patients. Genes characterized by significant alterations in histone H3-lysine 4 trimethylation (H3K4me3) showed differential enrichment in pathways involving immunoregulation, cell survival and signaling, and metabolism. Interestingly, a large subset of these genes was epigenetically regulated by microbiota in mice and several microbiota-sensitive epigenetic targets demonstrated altered expression in IBD patients. Remarkably though, a substantial proportion of these genes exhibited H3K4me3 levels that correlated with the severity of intestinal inflammation in IBD, despite lacking significant differential expression. Collectively, these data uncover a previously unrecognized epigenetic profile of IBD that can be primed by commensal microbes and indicate sensitive targets in the epithelium that may underlie how microbiota predispose to subsequent intestinal inflammation and disease.
View details for DOI 10.1172/jci.insight.122104
View details for Web of Science ID 000445115700018
View details for PubMedID 30232290
View details for PubMedCentralID PMC6237229
Validation of Neutrophil CD64 Blood Biomarkers to Detect Mucosal Inflammation in Pediatric Crohn's Disease
INFLAMMATORY BOWEL DISEASES
2018; 24 (1): 198-208
In a pilot study, neutrophil CD64 surface expression was significantly elevated in newly diagnosed, pediatric-onset Crohn's disease. We aimed to test the CD64 biomarkers (neutrophil CD64 surface expression and soluble CD64) as determinates for mucosal inflammation in a larger pediatric Crohn's cohort with the hypotheses that the CD64 biomarkers would reliably detect intestinal inflammation and correlate with endoscopic severity scores.We enrolled patients referred for colonoscopy for either suspected inflammatory bowel disease or with established Crohn's. Neutrophil CD64 index was determined by flow cytometry using a commercial kit (Leuko64, Trillium) and soluble CD64 by ELISA (LifeSpan).A total of 209 patients (72 controls, 76 new inflammatory bowel disease patients, and 61 established Crohn's) were enrolled. Both neutrophil CD64 index and soluble CD64 were significantly elevated in new Crohn's compared with controls. The area under the curve (AUC) for neutrophil CD64 index ≥1 was 0.85 (95% confidence interval, 0.77-0.92), 75% sensitive and 89% specific for new Crohn's. Comparatively, soluble CD64 ≥39 ng/mL was 92% sensitive and 85% specific (AUC, 0.93) for new Crohn's. Neutrophil CD64 index, soluble CD64, and fecal calprotectin discriminated endoscopic inactive from moderate and severe activity while soluble CD64 differentiated endoscopic mild from moderate and severe activity. Neutrophil CD64 index (r = 0.46, P < 0.001) and fecal calprotectin (r = 0.55, P < 0.001) correlated well with the Simple Endoscopic Score-Crohn's disease. Spearman correlation between the CD64 index and calprotectin was 0.39 (P < 0.001).In a large Crohn's disease cohort, we found that neutrophil CD64 index and soluble CD64 were significantly elevated during active gastrointestinal inflammation.
View details for DOI 10.1093/ibd/izx022
View details for Web of Science ID 000427524400021
View details for PubMedID 29272485
View details for PubMedCentralID PMC5831176
- MTG16 is a tumor suppressor in colitis-associated carcinoma JCI INSIGHT 2017; 2 (16)
MTG16 is a tumor suppressor in colitis-associated carcinoma.
2017; 2 (16)
MTG16 is a member of the myeloid translocation gene (MTG) family of transcriptional corepressors. While MTGs were originally identified in chromosomal translocations in acute myeloid leukemia, recent studies have uncovered a role in intestinal biology. For example, Mtg16-/- mice have increased intestinal proliferation and are more sensitive to intestinal injury in colitis models. MTG16 is also underexpressed in patients with moderate/severe ulcerative colitis. Based on these findings, we postulated that MTG16 might protect against colitis-associated carcinogenesis. MTG16 was downregulated at the protein and RNA levels in patients with inflammatory bowel disease and in those with colitis-associated carcinoma. Mtg16-/- mice subjected to inflammatory carcinogenesis modeling exhibited worse colitis and increased tumor multiplicity and size. Loss of MTG16 also increased severity of dysplasia, apoptosis, proliferation, DNA damage, and WNT signaling. Moreover, transplantation of WT marrow into Mtg16-/- mice failed to rescue the Mtg16-/- protumorigenic phenotypes, indicating an epithelium-specific role for MTG16. While MTG dysfunction is widely appreciated in hematopoietic malignancies, the role of this gene family in epithelial homeostasis, and in colon cancer, was unrealized. This report identifies MTG16 as an important modulator of colitis and tumor development in inflammatory carcinogenesis.
View details for DOI 10.1172/jci.insight.78210
View details for PubMedID 28814670
View details for PubMedCentralID PMC5621889
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
2017; 152 (6): 1345-+
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.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.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).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.
View details for DOI 10.1053/j.gastro.2017.01.016
View details for Web of Science ID 000401811300028
View details for PubMedID 28132889
View details for PubMedCentralID PMC5406257
Activation of TGF-beta activated kinase 1 promotes colon mucosal pathogenesis in inflammatory bowel disease
2017; 5 (7)
The etiology and mechanisms for inflammatory bowel disease (IBD) are incompletely known. Determination of new, clinically important mechanisms for intestinal inflammation is imperative for developing effective therapies to treat IBD We sought to define a widespread mechanism for colon mucosal inflammation via the activation of TGF-β activated Kinase 1 (TAK1), a central regulator of cellular inflammatory actions. Activation of TAK1 and the downstream inflammatory signaling mediators was determined in pediatric patients with ulcerative colitis (UC) or Crohn's disease (CD) as well as in DSS-induced and spontaneous IBD in mice. The role of TAK1 in facilitating intestinal inflammation in murine models of IBD was investigated by using (5Z)-7-Oxozeaenol, a highly selective pharmacological inhibitor of TAK1. We found hyper-activation of TAK1 in patients with UC or CD and in murine models of IBD Pharmacological inhibition of TAK1 prevented loss in body weight, disease activity, microscopic histopathology, infiltration of inflammatory cells in the colon mucosa, and elevated proinflammatory cytokine production in two murine models of IBD We demonstrated that at the early phase of the disease activation of TAK1 is restricted in the epithelial cells. However, at a more advanced stage of the disease, TAK1 activation predominantly occurs in nonepithelial cells, especially in macrophages. These findings elucidate the activation of TAK1 as crucial in promoting intestinal inflammation. Thus, the TAK1 activation pathway may represent a suitable target to design new therapies for treating IBD in humans.
View details for DOI 10.14814/phy2.13181
View details for Web of Science ID 000399683800006
View details for PubMedID 28373409
View details for PubMedCentralID PMC5392505
A Low Neutrophil CD64 Index Is Associated with Sustained Remission During Infliximab Maintenance Therapy
INFLAMMATORY BOWEL DISEASES
2016; 22 (11): 2641-2647
We have previously shown that CD64 surface expression on circulating neutrophils is significantly elevated in children with newly diagnosed Crohn's disease (CD). Our primary aim was to investigate whether elevations in neutrophil CD64 in asymptomatic patients could be used to predict treatment failure during maintenance infliximab.Pediatric CD subjects receiving maintenance infliximab in clinical remission (short pediatric CD activity index [shPCDAI] <15) were enrolled. We measured neutrophil CD64 expression (CD64 index, Trillium Diagnostics, LLC) and infliximab trough concentrations. Infliximab failure was defined as an shPCDAI >15 on 2 consecutive infusions, discontinuation of infliximab, hospitalization, endoscopic ulcerations, or surgery during the following year of maintenance infliximab.We enrolled 36 subjects, 22/36 were male and 29/36 were white. Mean (SD) age at study entry was 15 (4) years with a median of 14 (5-20) infusions before study entry. 4/36 were receiving a concurrent immunomodulator. Over 1 year, 15/36 subjects were classified as infliximab failures. Asymptomatic subjects with a neutrophil CD64 index >1 at study entry had a higher probability of treatment failure compared with asymptomatic subjects with a CD64 index <1 (log-rank = 0.002). We found only neutrophil CD64 index >1 and nonwhite race were risk factors for treatment failure by univariate regression analysis. We found no difference in the mean infliximab trough concentration at study entry between treatment failures (2.8 μg/mL, SD, 1.2) and subjects remaining in remission on infliximab (4.2 μg/mL, SD, 3.4; P = 0.17).Neutrophil CD64 index >1 is a significant risk factor for treatment failure during infliximab maintenance therapy.
View details for DOI 10.1097/MIB.0000000000000922
View details for Web of Science ID 000387248500017
View details for PubMedID 27749455
View details for PubMedCentralID PMC5117809
IL-33 Signaling Protects from Murine Oxazolone Colitis by Supporting Intestinal Epithelial Function
INFLAMMATORY BOWEL DISEASES
2015; 21 (12): 2737-2746
IL-33, a member of the IL-1 cytokine family that signals through ST2, is upregulated in ulcerative colitis (UC); however, the role of IL-33 in colitis remains unclear. IL-33 augments type 2 immune responses, which have been implicated in UC pathogenesis. We sought to determine the role of IL-33 signaling in oxazolone (OXA) colitis, a type 2 cytokine-mediated murine model of UC.Colon mucosal IL-33 expression was compared between pediatric and adult UC and non-IBD patients using immunohistochemistry and real-time PCR. OXA colitis was induced in WT, IL-33, and ST2 mice, and histopathology, cytokine levels, and goblet cells were assessed. Transepithelial resistance was measured across IL-33-treated T84 cell monolayers.Colon mucosal IL-33 was increased in pediatric patients with active UC and in OXA colitis. IL-33 and ST2 OXA mice exhibited increased disease severity compared with WT OXA mice. OXA induced a mixed mucosal cytokine response, but few differences were observed between OXA WT and IL-33 or ST2 mice. Goblet cells were significantly decreased in IL-33 and ST2 OXA compared with WT OXA mice. IL-33 augmented transepithelial resistance in T84 cells, and this effect was blocked by the ERK1/2 inhibitor PD98,059.OXA colitis is exacerbated in IL-33 and ST2 mice. Increased mucosal IL-33 in human UC and murine colitis may be a homeostatic response to limit inflammation, potentially through effects on epithelial barrier function. Further investigation of IL-33 protective mechanisms would inform the development of novel therapeutic approaches.
View details for DOI 10.1097/MIB.0000000000000532
View details for Web of Science ID 000365593500001
View details for PubMedID 26313694
View details for PubMedCentralID PMC4654638
Inflammatory Bowel Disease in Children and Adolescents
2015; 169 (11): 1053-1060
The inflammatory bowel diseases (IBDs), including ulcerative colitis and Crohn disease, are chronic inflammatory disorders of the gastrointestinal tract most often diagnosed in adolescence and young adulthood, with a rising incidence in pediatric populations. These disorders are common enough in children that most pediatricians and other pediatric clinicians will encounter children with IBD in their general practice. Inflammatory bowel disease is caused by a dysregulated mucosal immune response to the intestinal microflora in genetically predisposed hosts. Although children can present with the classic symptoms of weight loss, abdominal pain, and bloody diarrhea, many present with nonclassic symptoms of isolated poor growth, anemia, or other extraintestinal manifestations. Once IBD is diagnosed, the goals of therapy consist of eliminating symptoms, normalizing quality of life, restoring growth, and preventing complications while minimizing the adverse effects of medications. Unique considerations when treating children and adolescents with IBD include attention to the effects of the disease on growth and development, bone health, and psychosocial functioning. The purpose of this review is to provide a contemporary overview of the epidemiologic features, pathogenesis, diagnosis, and management of IBD in children and adolescents.
View details for DOI 10.1001/jamapediatrics.2015.1982
View details for Web of Science ID 000364430000016
View details for PubMedID 26414706
View details for PubMedCentralID PMC4702263
Treatment with immunosuppressive therapy may improve depressive symptoms in patients with inflammatory bowel disease.
Digestive diseases and sciences
2015; 60 (2): 465-70
Recent research suggests a relationship of inflammatory bowel disease (IBD) and depression. Our objective was to evaluate for improvement of depressive symptoms with treatment of IBD using immunosuppressive medications.A retrospective study of consecutive patients with IBD started on immunosuppressive agents [anti-tumor necrosis factor (anti-TNF) or immunomodulator therapy] was conducted. Patients were evaluated if disease activity indices using Harvey Bradshaw Index for Crohn's disease (CD) and Simple Clinical Colitis Disease Activity Index for ulcerative colitis (UC) and depressive indices using Patient Health Questionnaire-9 (PHQ-9) scores were obtained before and at least 30 days after initiation of therapy.Sixteen patients with UC and 53 patients with CD (all with active disease symptoms) were evaluated over a 60 day median follow-up evaluation (range 30, 140 days). Twenty-two patients started on immunomodulator therapy, and 47 patients started on anti-TNF therapy. Crohn's disease patients had significantly decreased PHQ-9 scores at follow-up [median 9 (range 3, 14) to 4 (1, 8)], with significant decreases only in those started on anti-TNF therapy. Changes in PHQ-9 and CRP were correlated (ρ = 0.38, p < 0.05). In patients with UC, PHQ-9 scores [5 (3, 9) to 2 (0, 5)] were significantly decreased. Percentage at risk of moderate to severe depression (PHQ-9 scores ≥10) was lower after treatment [Crohn's disease 51-18 % (p < 0.05), ulcerative colitis 18-0 %].Depressive scores decreased significantly in patients with IBD treated with immunosuppressive therapy and the number at risk for moderate to severe depression improved significantly.
View details for DOI 10.1007/s10620-014-3375-0
View details for PubMedID 25274158
- Letter: stool adalimumab detection in ulcerative colitis and Crohn's disease--authors' reply. Alimentary pharmacology & therapeutics 2015; 42 (2): 241
Endoscopic Diagnosis of Duodenal Stenosis in a 5-Month-Old Male Infant
2014; 47 (6): 568-570
Duodenal stenosis and duodenal atresia are well-known gastrointestinal anomalies in patients with Down syndrome. Although duodenal atresia presents early and classically with vomiting in the immediate neonatal period, the presentation of duodenal stenosis can be significantly more subtle and the diagnosis delayed. Here, we describe the case of a 5-month-old male infant with Down syndrome and delayed presentation of high-grade duodenal stenosis diagnosed endoscopically. Pediatric gastroenterologists should include duodenal stenosis in the differential diagnosis of older infants and children with vomiting and should be familiar with the endoscopic appearance of this lesion.
View details for DOI 10.5946/ce.2014.47.6.568
View details for Web of Science ID 000410057300016
View details for PubMedID 25505725
View details for PubMedCentralID PMC4260107
Small Intestinal Intraepithelial TCR gamma delta(+) T Lymphocytes Are Present in the Premature Intestine but Selectively Reduced in Surgical Necrotizing Enterocolitis (vol 9, e99042, 2014)
2014; 9 (8): e99042
Gastrointestinal barrier immaturity predisposes preterm infants to necrotizing enterocolitis (NEC). Intraepithelial lymphocytes (IEL) bearing the unconventional T cell receptor (TCR) γδ (γδ IEL) maintain intestinal integrity and prevent bacterial translocation in part through production of interleukin (IL) 17.We sought to study the development of γδ IEL in the ileum of human infants and examine their role in NEC pathogenesis. We defined the ontogeny of γδ IEL proportions in murine and human intestine and subjected tcrδ-/- mice to experimental gut injury. In addition, we used polychromatic flow cytometry to calculate percentages of viable IEL (defined as CD3+ CD8+ CD103+ lymphocytes) and the fraction of γδ IEL in surgically resected tissue from infants with NEC and gestational age matched non-NEC surgical controls.In human preterm infants, the proportion of IEL was reduced by 66% in 11 NEC ileum resections compared to 30 non-NEC controls (p<0.001). While γδ IEL dominated over conventional αβ IEL early in gestation in mice and in humans, γδ IEL were preferential decreased in the ileum of surgical NEC patients compared to non-NEC controls (50% reduction, p<0.05). Loss of IEL in human NEC was associated with downregulation of the Th17 transcription factor retinoic acid-related orphan nuclear hormone receptor C (RORC, p<0.001). TCRδ-deficient mice showed increased severity of experimental gut injury (p<0.05) with higher TNFα expression but downregulation of IL17A.Complimentary mouse and human data suggest a role of γδ IEL in IL17 production and intestinal barrier production early in life. Specific loss of the γδ IEL fraction may contribute to NEC pathogenesis. Nutritional or pharmacological interventions to support γδ IEL maintenance in the developing small intestine could serve as novel strategies for NEC prevention.
View details for DOI 10.1371/journal.pone.0105487
View details for Web of Science ID 000339995100097
View details for PubMedID 24905458
View details for PubMedCentralID PMC4048281
- Small Intestinal Intraepithelial TCR gamma delta(+) T Lymphocytes Are Present in the Premature Intestine but Selectively Reduced in Surgical Necrotizing Enterocolitis PLOS ONE 2014; 9 (6)
Outcomes following infliximab therapy for pediatric patients hospitalized with refractory colitis-predominant IBD.
Journal of pediatric gastroenterology and nutrition
2014; 58 (2): 213-9
Although randomized trials demonstrated the efficacy of infliximab for both pediatric Crohn disease and ulcerative colitis (UC), few patients in these studies exhibited colitis requiring hospitalization. The aims of this study were to determine the rate of subsequent infliximab failure and dose escalation in pediatric patients who started taking infliximab during hospitalization for colitis-predominant IBD, and to identify potential predictors of these endpoints.This is a single-center retrospective cohort study of patients admitted from 2005 to 2010 with Crohn colitis, UC, or IBD-unspecified (IBD-U) and initiated on infliximab.We identified 29 patients (12 Crohn colitis, 15 UC, and 2 IBD-U; median age 14 years) with a median follow-up of 923 days. Eighteen patients (62%) required infliximab dose escalation (increased dose or decreased infusion interval). Infliximab failure occurred in 18 patients (62%) because of ineffectiveness in 12 (67%) and adverse reactions in 6 (33%). Twelve patients (41%) underwent colectomy. Subsequent need for infliximab dose escalation was associated with lower body mass index z score (P = 0.01), lower serum albumin (P = 0.03), and higher erythrocyte sedimentation rate (ESR) (P = 0.002) at baseline. ESR predicted subsequent infliximab dose escalation with an area under the curve of 0.89 (95% confidence interval [CI] 0.72-1.00) and a sensitivity and specificity at a cutoff of 38 mm/hour of 0.79 (95% CI 0.49-0.95) and 0.88 (95% CI 0.47-0.99), respectively.Most hospitalized pediatric patients with colitis treated with infliximab require early-dose escalation and fail the drug long term. Low body mass index and albumin and high ESR, may identify patients who would benefit from a higher infliximab starting dose.
View details for DOI 10.1097/MPG.0b013e3182a98df2
View details for PubMedID 24048170
View details for PubMedCentralID PMC3946904
Activation of the epidermal growth factor receptor in macrophages regulates cytokine production and experimental colitis.
Journal of immunology (Baltimore, Md. : 1950)
2014; 192 (3): 1013-23
Macrophages regulate innate immunity to maintain intestinal homeostasis and play pathological roles in intestinal inflammation. Activation of the epidermal growth factor receptor (EGFR) promotes cellular proliferation, differentiation, survival, and wound closure in several cell types. However, the impact of EGFR in macrophages remains unclear. This study was to investigate whether EGFR activation in macrophages regulates cytokine production and intestinal inflammation. We found that EGFR was activated in colonic macrophages in mice with dextran sulfate sodium (DSS)-induced colitis and in patients with ulcerative colitis. DSS-induced acute colitis was ameliorated, and recovery from colitis was promoted in Egfr(fl/fl)LysM-Cre mice with myeloid cell-specific deletion of EGFR, compared with LysM-Cre mice. DSS treatment increased IL-10 and TNF levels during the acute phase of colitis, and increased IL-10 but reduced TNF levels during the recovery phase in Egfr(fl/fl)LysM-Cre mice. An anti-IL-10 neutralizing Ab abolished these effects of macrophage-specific EGFR deletion on DSS-induced colitis in Egfr(fl/fl)LysM-Cre mice. LPS stimulated EGFR activation and inhibition of EGFR kinase activity enhanced LPS-stimulated NF-κB activation in RAW 264.7 macrophages. Furthermore, induction of IL-10 production by EGFR kinase-blocked RAW 264.7 cells, in response to LPS plus IFN-γ, correlated with decreased TNF production. Thus, although selective deletion of EGFR in macrophages leads to increases in both pro- and anti-inflammatory cytokines in response to inflammatory stimuli, the increase in the IL-10 level plays a role in suppressing proinflammatory cytokine production, resulting in protection of mice from intestinal inflammation. These results reveal an integrated response of macrophages regulated by EGFR in intestinal inflammatory disorders.
View details for DOI 10.4049/jimmunol.1300133
View details for PubMedID 24391216
View details for PubMedCentralID PMC4006992
STAT6 Deficiency Ameliorates Severity of Oxazolone Colitis by Decreasing Expression of Claudin-2 and Th2-Inducing Cytokines
JOURNAL OF IMMUNOLOGY
2013; 190 (4): 1849-1858
Patients suffering from ulcerative colitis (UC) exhibit chronic colonic inflammation caused by a dysregulated mucosal immune response and epithelial barrier disruption. Th2 cytokines, including IL-13, have been implicated in the pathogenesis of UC. IL-13 induces phosphorylation of STAT6, and we previously demonstrated increased epithelial p-STAT6 in children with UC. In this study, we investigated the role of STAT6 in oxazolone colitis, a murine model of UC, by inducing colitis in STAT6-deficient (STAT6(-/-)) and wild type (WT) mice. We observed increased epithelial cell, T cell, macrophage, and NKT cell STAT6 phosphorylation, as well as increased p-STAT6(+) IL-13-producing NKT cells, in colitic WT mice. Colitis was attenuated in STAT6(-/-) mice, with improvements in weight, colon length, and histopathology. There was decreased induction of the pore-forming tight junction protein claudin-2 in STAT6(-/-) mice. Similarly, short hairpin RNA STAT6 knockdown reduced claudin-2 induction and transepithelial resistance decrease in IL-13-treated human T84 cells. Tissue expression of IL-13, IFN-γ, IL-17, and IL-10 mRNA was similarly induced in WT and STAT6(-/-) colitic mice; however, we observed increased mRNA expression for the Th2-inducing cytokines IL-33 and thymic stromal lymphopoietin in WT mice with colitis, which was abrogated in STAT6(-/-) mice. Mesenteric lymph node cells from STAT6(-/-) mice with colitis exhibited reduced secretion of IL-4, IL-5, IL-13, and IFN-γ. IL-33 augmented mesenteric lymph node cell secretion of IL-5, IL-13, IL-6, and IFN-γ. These data implicate STAT6 in the pathogenesis of colitis in vivo with important roles in altering epithelial barrier function and regulating Th2-inducing cytokine production.
View details for DOI 10.4049/jimmunol.1201373
View details for Web of Science ID 000314825400048
View details for PubMedID 23303670
View details for PubMedCentralID PMC3563924
High-throughput multi-analyte Luminex profiling implicates eotaxin-1 in ulcerative colitis.
2013; 8 (12): e82300
Accurate and high-throughput technologies are needed for identification of new therapeutic targets and for optimizing therapy in inflammatory bowel disease. Our aim was to assess multi-analyte protein-based assays of cytokines/chemokines using Luminex technology. We have reported that Luminex-based profiling was useful in assessing response to L-arginine therapy in the mouse model of dextran sulfate sodium colitis. Therefore, we studied prospectively collected samples from ulcerative colitis (UC) patients and control subjects. Serum, colon biopsies, and clinical information were obtained from subjects undergoing colonoscopy for evaluation of UC or for non-UC indications. In total, 38 normal controls and 137 UC cases completed the study. Histologic disease severity and the Mayo Disease Activity Index (DAI) were assessed. Serum and colonic tissue cytokine/chemokine profiles were measured by Luminex-based multiplex testing of 42 analytes. Only eotaxin-1 and G-CSF were increased in serum of patients with histologically active UC vs. controls. While 13 cytokines/chemokines were increased in active UC vs. controls in tissues, only eotaxin-1 was increased in all levels of active disease in both serum and tissue. In tissues, eotaxin-1 correlated with the DAI and with eosinophil counts. Increased eotaxin-1 levels were confirmed by real-time PCR. Tissue eotaxin-1 levels were also increased in experimental murine colitis induced by dextran sulfate sodium, oxazolone, or Citrobacter rodentium, but not in murine Helicobacter pylori infection. Our data implicate eotaxin-1 as an etiologic factor and therapeutic target in UC, and indicate that Luminex-based assays may be useful to assess IBD pathogenesis and to select patients for anti-cytokine/chemokine therapies.
View details for DOI 10.1371/journal.pone.0082300
View details for PubMedID 24367513
View details for PubMedCentralID PMC3867379
Necrotising enterocolitis is characterised by disrupted immune regulation and diminished mucosal regulatory (FOXP3)/effector (CD4, CD8) T cell ratios.
2013; 62 (1): 73-82
Necrotising enterocolitis (NEC) is the most common gastrointestinal emergency in premature infants. Immaturity of gastrointestinal immune regulation may predispose preterm infants to NEC as FOXP3 T regulatory cells (Treg) are critical for intestinal immune homoeostasis.To investigate the hypothesis that abnormal developmental regulation of lamina propria Treg would define premature infants with NEC.Lamina propria mononuclear cell populations from surgically resected ileum from 18 patients with NEC and 30 gestational age-matched non-NEC surgical controls were prospectively isolated. Polychromatic flow cytometry was performed to phenotype and analyse lamina propria T cell populations. The cytokine gene expression profile in NEC tissue was compared with that of non-NEC controls.The total number of Treg, CD4, or CD8 T cells in each ileum section was independent of gestational age, age or postmenstrual age and similar between patients with NEC and controls. In contrast, the ratio of Treg to CD4 T cells or Treg to CD8 T cells was significantly lower in NEC ileum than in infants without NEC (medians 2.9% vs 6.6%, p=0.001 and medians 6.6% vs 25.9%, p<0.001, respectively). For any given number of CD4 or CD8 T cells, Treg were, on average, 60% lower in NEC ileum than in controls. NEC tissue cytokine gene expression profiles were characteristic of inhibited Treg development or function. Treg/CD4 and Treg/CD8 ratios recovered between initial resection for NEC and reanastomosis.The proportion of lamina propria Treg is significantly reduced in the ileum of premature infants with NEC and may contribute to the excessive inflammatory state of this disease.
View details for DOI 10.1136/gutjnl-2011-301551
View details for PubMedID 22267598
View details for PubMedCentralID PMC3606820
Deletion of cationic amino acid transporter 2 exacerbates dextran sulfate sodium colitis and leads to an IL-17-predominant T cell response.
American journal of physiology. Gastrointestinal and liver physiology
2013; 305 (3): G225-40
L-Arginine (L-Arg) is a semiessential amino acid that has altered availability in human ulcerative colitis (UC), a form of inflammatory bowel disease, and is beneficial in murine colitis induced by dextran sulfate sodium (DSS), a model with similarity to UC. We assessed the role of cationic amino acid transporter 2 (CAT2), the inducible transporter of L-Arg, in DSS colitis. Expression of CAT2 was upregulated in tissues from colitic mice and localized predominantly to colonic macrophages. CAT2-deficient (CAT2-/-) mice exposed to DSS exhibited worsening of survival, body weight loss, colon weight, and histological injury. These effects were associated with increased serum L-Arg and decreased tissue L-Arg uptake and inducible nitric oxide synthase protein expression. Clinical benefits of L-Arg supplementation in wild-type mice were lost in CAT2-/- mice. There was increased infiltration of macrophages, dendritic cells, granulocytes, and T cells in colitic CAT2-/- compared with wild-type mice. Cytokine profiling revealed increases in proinflammatory granulocyte colony-stimulating factor, macrophage inflammatory protein-1α, IL-15, and regulated and normal T cell-expressed and -secreted and a shift from an IFN-γ- to an IL-17-predominant T cell response, as well as an increase in IL-13, in tissues from colitic CAT2-/- mice. However, there were no increases in other T helper cell type 2 cytokines, nor was there a global increase in macrophage-derived proinflammatory cytokines. The increase in IL-17 derived from both CD4 and γδ T cells and was associated with colonic IL-6 expression. Thus CAT2 plays an important role in controlling inflammation and IL-17 activation in an injury model of colitis, and impaired L-Arg availability may contribute to UC pathogenesis.
View details for DOI 10.1152/ajpgi.00091.2013
View details for PubMedID 23703655
View details for PubMedCentralID PMC3742860
Mycophenolate mofetil-related enterocolitis and weight loss: a pediatric case series.
Case reports in pediatrics
2012; 2012: 624168
Mycophenolate mofetil (MMF) is an immunosuppressive medication utilized in the management of both autoimmune and solid organ transplant patients. Diarrhea is a common gastrointestinal side effect of MMF, but more severe forms of GI symptoms are described in renal transplant patients with a distinct pattern of histopathologic change, similar to graft-versus-host disease or Crohn's disease. This rare entity, commonly referred to as "MMF-related enterocolitis," has been described in adult patients, mostly in renal transplant patients, and in only two pediatric renal transplant patients. In previously reported cases, symptoms and abnormal histopathology improve with dose reduction of MMF. We describe a series of three pediatric patients with varied underlying disease process who presented with severe diarrhea and histopathologic findings characteristic of MMF-related enterocolitis, who share a novel finding of weight loss as a complication of MMF-related enterocolitis in pediatric patients.
View details for DOI 10.1155/2012/624168
View details for PubMedID 23133776
View details for PubMedCentralID PMC3485763
Transactivation of EGFR by LPS induces COX-2 expression in enterocytes.
2012; 7 (5): e38373
Necrotizing enterocolitis (NEC) is the leading cause of gastrointestinal morbidity and mortality in preterm infants. NEC is characterized by an exaggerated inflammatory response to bacterial flora leading to bowel necrosis. Bacterial lipopolysaccharide (LPS) mediates inflammation through TLR4 activation and is a key molecule in the pathogenesis of NEC. However, LPS also induces cyclooxygenase-2 (COX-2), which promotes intestinal barrier restitution through stimulation of intestinal cell survival, proliferation, and migration. Epidermal growth factor receptor (EGFR) activation prevents experimental NEC and may play a critical role in LPS-stimulated COX-2 production. We hypothesized that EGFR is required for LPS induction of COX-2 expression. Our data show that inhibiting EGFR kinase activity blocks LPS-induced COX-2 expression in small intestinal epithelial cells. LPS induction of COX-2 requires Src-family kinase signaling while LPS transactivation of EGFR requires matrix metalloprotease (MMP) activity. EGFR tyrosine kinase inhibitors block LPS stimulation of mitogen-activated protein kinase ERK, suggesting an important role of the MAPK/ERK pathway in EGFR-mediated COX-2 expression. LPS stimulates proliferation of IEC-6 cells, but this stimulation is inhibited with either the EGFR kinase inhibitor AG1478, or the selective COX-2 inhibitor Celecoxib. Taken together, these data show that EGFR plays an important role in LPS-induction of COX-2 expression in enterocytes, which may be one mechanism for EGF in inhibition of NEC.
View details for DOI 10.1371/journal.pone.0038373
View details for PubMedID 22675459
View details for PubMedCentralID PMC3364993
- Commentaries on "Workshop report: developing a pediatric inflammatory bowel diseases network and data platform in Canada": pediatric inflammatory bowel disease networks: raising the bar. Journal of pediatric gastroenterology and nutrition 2012; 55 (2): 121-2
L-arginine supplementation improves responses to injury and inflammation in dextran sulfate sodium colitis.
2012; 7 (3): e33546
Inflammatory bowel disease (IBD), consisting of Crohn's disease and ulcerative colitis (UC), results in substantial morbidity and is difficult to treat. New strategies for adjunct therapies are needed. One candidate is the semi-essential amino acid, L-arginine (L-Arg), a complementary medicine purported to be an enhancer of immunity and vitality in the lay media. Using dextran sulfate sodium (DSS) as a murine colonic injury and repair model with similarities to human UC, we assessed the effect of L-Arg, as DSS induced increases in colonic expression of the y(+) cationic amino acid transporter 2 (CAT2) and L-Arg uptake. L-Arg supplementation improved the clinical parameters of survival, body weight loss, and colon weight, and reduced colonic permeability and the number of myeloperoxidase-positive neutrophils in DSS colitis. Luminex-based multi-analyte profiling demonstrated that there was a marked reduction in proinflammatory cytokine and chemokine expression with L-Arg treatment. Genomic analysis by microarray demonstrated that DSS-treated mice supplemented with L-Arg clustered more closely with mice not exposed to DSS than to those receiving DSS alone, and revealed that multiple genes that were upregulated or downregulated with DSS alone exhibited normalization of expression with L-Arg supplementation. Additionally, L-Arg treatment of mice with DSS colitis resulted in increased ex vivo migration of colonic epithelial cells, suggestive of increased capacity for wound repair. Because CAT2 induction was sustained during L-Arg treatment and inducible nitric oxide (NO) synthase (iNOS) requires uptake of L-Arg for generation of NO, we tested the effect of L-Arg in iNOS(-/-) mice and found that its benefits in DSS colitis were eliminated. These preclinical studies indicate that L-Arg supplementation could be a potential therapy for IBD, and that one mechanism of action may be functional enhancement of iNOS activity.
View details for DOI 10.1371/journal.pone.0033546
View details for PubMedID 22428068
View details for PubMedCentralID PMC3299802
- 15-year-old girl with metaplastic atrophic gastritis and enterochromaffin-like cell hyperplasia. Journal of pediatric gastroenterology and nutrition 2012; 55 (6): e148-51
STAT6 activation in ulcerative colitis: a new target for prevention of IL-13-induced colon epithelial cell dysfunction.
Inflammatory bowel diseases
2011; 17 (11): 2224-34
Interleukin 13 (IL-13) is upregulated in ulcerative colitis (UC) and increases colon epithelial permeability by inducing apoptosis and expression of the pore-forming tight junction protein claudin-2. IL-13 induces activation of signal transducer and activator of transcription 6 (STAT6). However, the STAT6 phosphorylation status in patients with UC is unknown, as is the effect of STAT6 inhibition on colonic epithelium exposed to IL-13. The study aims were to determine if mucosal STAT6 phosphorylation is increased in patients with UC, and if STAT6 inhibition attenuates IL-13-induced colon epithelial cell dysfunction.Immunohistochemical staining for phosphorylated (p) STAT6 was performed on colonic tissue from newly diagnosed pediatric subjects with UC (early UC) or Crohn's disease (CD), colectomy tissue from adults with UC (advanced UC), and controls. Colon HT-29 and T84 cells were transfected with STAT6 small interfering RNA (siRNA), or treated with suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor that inhibits STAT6, prior to IL-13 treatment.The median score for epithelial pSTAT6 was 0 in control subjects, 2 in early UC (versus control P = 0.019), 4 in advanced UC (P = 0.003), and 0 in CD (P = 0.4). Cell transfection with STAT6 siRNA prevented IL-13-induced apoptosis and claudin-2 expression. SAHA inhibited IL-13-induced STAT6 phosphorylation, apoptosis, and claudin-2 expression, and mitigated IL-13-induced reductions in transepithelial resistance.UC is associated with increased colonic epithelial STAT6 phosphorylation, and STAT6 inhibition prevents IL-13-induced apoptosis and barrier disruption. These data identify STAT6 as a novel target for UC treatment and support further study of SAHA as a therapeutic agent.
View details for DOI 10.1002/ibd.21628
View details for PubMedID 21308881
View details for PubMedCentralID PMC3120916
Ciliated hepatic foregut cysts in children.
Pediatric surgery international
2010; 26 (7): 753-7
Ciliated hepatic foregut cyst (CHFC) is a rare foregut developmental malformation usually diagnosed in adulthood; however, rare cases have been reported in the pediatric population. CHFC can transform into a squamous cell carcinoma resulting in death despite surgical resection of the isolated malignancy. We report the presentation, evaluation, and surgical management of a symptomatic 17-year-old girl found to have a 6.5 x 4.5 cm CHFC and suggest that all patients with suspected CHFC undergo prompt evaluation and complete cyst excision.
View details for DOI 10.1007/s00383-009-2468-x
View details for PubMedID 19760201
View details for PubMedCentralID PMC3718281
Endoscopic ultrasound to guide the combined medical and surgical management of pediatric perianal Crohn's disease.
Inflammatory bowel diseases
2010; 16 (3): 461-8
Perianal fistulas are a debilitating manifestation of Crohn's disease (CD) in the pediatric population and present a management challenge. The aims of this study were to describe our experience using endoscopic ultrasound (EUS) to guide management of perianal CD (PCD) in a pediatric population, and determine whether using EUS to monitor healing after seton placement improves outcomes.We conducted a retrospective study of 2 cohorts: pediatric subjects with PCD who underwent EUS and pediatric subjects who underwent seton placement between 2002 and 2007.In all, 25 children underwent a total of 42 EUS procedures. Of 28 EUSs performed to evaluate suspected perianal disease, complex fistulizing disease was identified in 15 (54%). Setons were placed after most EUSs demonstrating complex fistulizing disease and after none demonstrating superficial or no fistulizing disease. Of 14 EUSs performed to monitor healing around a seton, 7 (50%) demonstrated persistent peri-seton inflammation. Setons were more often left in place after an EUS revealing persistent inflammation (86% versus 0%), and the patients were more likely to have a biologic initiated or changed (57% versus 0%). Among all subjects who underwent seton placement, time from seton removal to recurrence was longer for those followed by EUS compared to those followed by physical exam only; however, we were not powered to test for statistical significance.EUS to guide the combined medical and surgical management of PCD is feasible in the pediatric population. Larger prospective studies are needed to determine if EUS-directed management improves outcomes in pediatric patients with PCD.
View details for DOI 10.1002/ibd.21067
View details for PubMedID 19637325
View details for PubMedCentralID PMC2871764
- A 31-year-old patient with colitis and perianal disease. Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association 2010; 8 (1): 10-4
A randomized prospective trial of endoscopic ultrasound to guide combination medical and surgical treatment for Crohn's perianal fistulas.
The American journal of gastroenterology
2008; 103 (10): 2527-35
To prospectively determine if rectal endoscopic ultrasound (EUS) can guide combination medical and surgical therapy and improve outcomes for patients with perianal fistulizing Crohn's disease.Ten patients with perianal Crohn's disease were prospectively enrolled in a randomized prospective pilot study. The patients were randomized to either the EUS cohort or the control group. All patients underwent a rectal EUS to delineate fistula anatomy followed by an examination under anesthesia by a colorectal surgeon with seton placement and/or incision and drainage, as indicated. The surgeon was blinded to the initial EUS results of patients in the control group. Medical treatment was maximized with 6-mercaptopurine (1.0-1.5 mg/kg) or azathioprine (2.0-2.5 mg/kg), ciprofloxacin (1,000 mg a day) or metronidazole (1,500 mg a day), and infliximab (5 mg/kg at 0, 2, and 6 wk and then every 8 wk). For patients in the control group, additional interventions (seton removal and repeat surgery) were at the discretion of the surgeon (without EUS guidance). Patients in the EUS cohort had EUS performed at weeks 22 and 38, with additional surgical interventions based on EUS findings. The primary end point was complete cessation of drainage at week 54. All patients had a repeat EUS performed at week 54 to determine the fistula status on EUS (secondary end point). The need for additional surgery was defined as a treatment failure.Ten patients were enrolled in the study. One of 5 (20%) in the control group and 4 of 5 (80%) in the EUS group had complete cessation of drainage. From the control group, 3 patients failed due to repeat surgery (2 for persistent/recurrent fistula and 1 for abscess), and 1 had a persistent drainage at week 54. In the EUS cohort, 1 patient had a recurrent abscess after his seton fell out prematurely. In the EUS cohort, the median time to cessation of drainage was 99 days, and the time to EUS evidence of fistula inactivity was 229 days.This pilot study suggests that using EUS to guide combination medical and surgical therapy for perianal fistulizing Crohn's disease improves the outcomes.
View details for DOI 10.1111/j.1572-0241.2008.02063.x
View details for PubMedID 18684178
Acute appendicitis following colonoscopy.
Journal of clinical gastroenterology
2005; 39 (1): 78
View details for PubMedID 15599219
Anti-Saccharomyces cerevisiae antibody (ASCA) positivity is associated with increased risk for early surgery in Crohn's disease.
2004; 53 (8): 1117-22
Anti-Saccharomyces cerevisiae antibodies (ASCA) are a specific but only moderately sensitive diagnostic marker for Crohn's disease. We sought to explore the role of ASCA as a prognostic marker for aggressive disease phenotype in Crohn's disease.To determine the role of ASCA status as a risk factor for early surgery in Crohn's disease.We performed a case control study in a cohort of patients, newly diagnosed with Crohn's disease, between 1991 and 1999. All patients were followed for at least three years. Case subjects (n = 35) included those who had major surgery for Crohn's disease within three years of diagnosis. Controls (n = 35) included patients matched to cases for age, sex, disease location, and smoking status, and who did not undergo major surgery for Crohn's disease within three years of diagnosis.Blinded assays were performed on serum for ASCA (immunoglobulin (Ig)A and IgG). A paired analysis of cases-controls was performed to test for the association between ASCA status and risk of early surgery.ASCA IgA was strongly associated with early surgery (odds ratio (OR) 8.5 (95% confidence interval (CI) 2.0-75.9); p = 0.0013). ASCA IgG+ and ASCA IgG+/IgA+ patients were also at increased risk for early surgery (OR 5.5 (95% CI 1.2-51.1), p = 0.0265; and OR 5.0 (95% CI 1.1-46.9), p = 0.0433, respectively). The association between ASCA and early surgery was evident in patients requiring surgery for ileal or ileocolonic disease.Patients with Crohn's disease who are positive for ASCA IgA, IgG, or both, may define a subset of patients with Crohn's disease at increased risk for early surgery.
View details for DOI 10.1136/gut.2003.030734
View details for PubMedID 15247177
View details for PubMedCentralID PMC1774147
Risk of early surgery for Crohn's disease: implications for early treatment strategies.
The American journal of gastroenterology
2003; 98 (12): 2712-8
In this study we aimed to define the rate of early surgery for Crohn's disease and to identify risk factors associated with early surgery as a basis for subsequent studies of early intervention in Crohn's disease.We assembled a retrospective cohort of patients with Crohn's disease diagnosed between 1991 and 1997 and followed for at least 3 yr, who were identified in 16 community and referral-based practices in New England. Chart review was performed for each patient. Details of baseline demographic and disease features were recorded. Surgical history including date of surgery, indication, and procedure were also noted. Risk factors for early surgery (defined as major surgery for Crohn's disease within 3 yr of diagnosis, exclusive of major surgery at time of diagnosis) were identified by univariate analysis. Multiple logistic regression was used to identify independent risk factors.Of 345 eligible patients, 69 (20.1%) required surgery within 3 yr of diagnosis, excluding the 14 patients (4.1%) who had major surgery at the time of diagnosis. Overall, the interval between diagnosis and surgery was short; one half of all patients who required surgery underwent operation within 6 months of diagnosis. Risk factors identified by univariate analysis as significantly associated with early surgery included the following: smoking; disease of small bowel without colonic involvement; nausea and vomiting or abdominal pain on presentation; neutrophil count; and steroid use in the first 6 months. Disease localized to the colon only, blood in the stool, use of 5-aminosalicylate, and lymphocyte count were inversely associated with risk of early surgery. Logistic regression confirmed independent associations with smoking as a positive risk factor and involvement of colon without small bowel as a negative risk factor for early surgery.The rate of surgery is high in the first 3 yr after diagnosis of Crohn's disease, particularly in the first 6 months. These results suggest that improved risk stratification and potent therapies with rapid onset of action are needed to modify the natural history of Crohn's disease.
View details for DOI 10.1111/j.1572-0241.2003.08674.x
View details for PubMedID 14687822