Epithelial-mesenchymal transition, regulated by ß-catenin and Twist, leads to esophageal wall remodeling in pediatric eosinophilic esophagitis.

Eosinophilic Esophagitis (EoE) is an antigen-triggered inflammatory condition of the esophageal lining characterized by eosinophilic infiltration. EoE is associated with significant remodeling, and although this remodeling is reversed by current treatment regimens, symptoms of EoE and associated remodeling reappear upon cessation of therapies. We hypothesized that structural remodeling of cell-cell adhesion is a key factor in the pathogenesis of EoE and that epithelial to mesenchymal transition (EMT) was a viable molecular process to lead to this remodeling. Endoscopically obtained biopsy samples from 18 EoE and 18 control pediatric patients were evaluated by transmission electron microscopy to measure intercellular spaces (IS) between cells. Biopsy samples from all groups were analyzed for cellular levels of cell-cell adhesion proteins: E-cadherin, zonula occludens associated protein-1 (ZO-1), and N-cadherin. We also analyzed for cellular levels and localization two of transcription factors, Twist1 and ß-catenin, that are associated with promoting EMT. The IS was significantly increased in the EoE group compared to the control. We observed a significant decrease in E-cadherin and ZO-1 levels and a concomitant increase in N-cadherin levels in EoE samples compared to control. Further, while there was no significant change in cellular levels of ß-catenin, we observed an altered localization of the protein from the cell membrane in control tissue to a nuclear/perinuclear localization in EoE. We observed higher levels of the transcription factor Twist1 in the EoE group compared to normal which was localized mainly at the nucleus. Our results suggest that the integrity of normally sealed esophageal epithelia is compromised in the EoE patients compared to control subjects, and this is due to alterations in the expression of cell adhesion molecules at the esophageal epithelium. Our data also suggest that EMT, potentially regulated by transcription factors ß-catenin and Twist1, may be responsible for the molecular alteration which leads to the remodeling of esophageal epithelia in EoE.

Endoscopy simulation for pre-clerkship students.

Here we report a simulation session carried out with pre-clerkship medical students during their gastroenterology block. We used endoscopy simulator to cement the clinical and anatomic implications of endoscopy and to build interest in gastroenterology. Students thought the session was helpful for their interest and understanding. Endoscopy simulation provided for pre-clinical students is an enjoyable adjunct to gastroenterology learning.

Nous rapportons ici une séance de simulation réaliséeavec des étudiants en médecine au pré-externatet pendant leur bloc de gastro-entérologie. Nous utilisons un simulateur d'endoscopie pour consoliderles implications cliniques et anatomiques de l'endoscopie et pour susciter un intérêt pour la gastro-entérologie. Les étudiants ont considéré la séance comme utile pour leurs intérêts et leur compréhension. Une simulation d'endoscopie offerte aux étudiants fu pré-externat est un complément agréable à leur apprentissage en gastro-entérologie.

A Canadian Study toward Changing Local Practice in the Diagnosis of Pediatric Celiac Disease.

Background. The European Society for Pediatric Gastroenterology, Hepatology and Nutrition endorses serological diagnosis (SD) for pediatric celiac disease (CD). The objective of this study was to pilot SD and to prospectively evaluate gastrointestinal permeability and mucosal inflammation at diagnosis and after one year on the gluten-free diet (GFD). We hypothesized that SD would be associated with similar short term outcomes as ED. Method. Children, 3-17 years of age, referred for possible CD were eligible for SD given aTTG level ≥200 U/mL, confirmed by repeat aTTG and HLA haplotypes. Gastrointestinal permeability, assessed using sugar probes, and inflammation, assessed using fecal calprotectin (FC), at baseline and after one year on a GFD were compared to patients who had ED. Results. Enrolled SD (n = 40) and ED (n = 48) patients had similar demographics. ED and SD groups were not different in baseline lactulose: mannitol ratio (L : M) (0.049 versus 0.034; p = 0.07), fractional excretion of sucrose (%FES; 0.086 versus 0.092; p = 0.44), or fecal calprotectin (FC; 89.6 versus 51.4; p = 0.05). At follow-up, urine permeability improved and was similar between groups, L : M (0.022 versus 0.025; p = 0.55) and %FES (0.040 versus 0.047; p = 0.87) (p > 0.05). FC improved but remained higher in the SD group (37.1 versus 15.9; p = 0.04). Conclusion. Patients on the GFD showed improved intestinal permeability and mucosal inflammation regardless of diagnostic strategy. This prospective study supports that children diagnosed by SD have resolving mucosal disease early after commencing a GFD.

Reduced sodium/proton exchanger NHE3 activity causes congenital sodium diarrhea.

Congenital sodium diarrhea (CSD) refers to an intractable diarrhea of intrauterine onset with high fecal sodium loss. CSD is clinically and genetically heterogeneous. Syndromic CSD is caused by SPINT2 mutations. While we recently described four cases of the non-syndromic form of CSD that were caused by dominant activating mutations in intestinal receptor guanylate cyclase C (GC-C), the genetic cause for the majority of CSD is still unknown. Therefore, we aimed to determine the genetic cause for non-GC-C non-syndromic CSD in 18 patients from 16 unrelated families applying whole-exome sequencing and/or chromosomal microarray analyses and/or direct Sanger sequencing. SLC9A3 missense, splicing and truncation mutations, including an instance of uniparental disomy, and whole-gene deletion were identified in nine patients from eight families with CSD. Two of these nine patients developed inflammatory bowel disease (IBD) at 4 and 16 years of age. SLC9A3 encodes Na(+)/H(+) antiporter 3 (NHE3), which is the major intestinal brush-border Na(+)/H(+) exchanger. All mutations were in the NHE3 N-terminal transport domain, and all missense mutations were in the putative membrane-spanning domains. Identified SLC9A3 missense mutations were functionally characterized in plasma membrane NHE null fibroblasts. SLC9A3 missense mutations compromised NHE3 activity by reducing basal surface expression and/or loss of basal transport function of NHE3 molecules, whereas acute regulation was normal. This study identifies recessive mutations in NHE3, a downstream target of GC-C, as a cause of CSD and implies primary basal NHE3 malfunction as a predisposition for IBD in a subset of patients.

Exploring anthropometric and laboratory differences in children of varying ethnicities with celiac disease.

BACKGROUND: Celiac disease (CD) is a common autoimmune disorder with an increasing prevalence, including in ethnic minorities. OBJECTIVE: To report the frequency of CD diagnosis in ethnic minorities presenting to a Canadian pediatric celiac clinic and to determine whether ethnic differences exist at diagnosis or follow-up. METHODS: Patients with biopsy-proven CD diagnosed at a multidisciplinary celiac clinic between 2008 and 2011 were identified through the clinic database. Data at referral, and six-month and 12-month follow-ups were collected. These included demographics, self-reported ethnicity, symptoms, anthropometrics and laboratory investigations, including serum immunoglobulin antitissue transglutaminase (aTTG). RESULTS: A total of 272 patients were identified; 80% (n = 218) were Caucasian (group 1) and 20% (n = 54) were other ethnicities. South Asians (group 2) comprised 81% (n = 44) of the minority population. No differences in age or sex were found between the two groups. Group 1 patients presented more often with gastrointestinal symptoms (71% versus 43%; P < 0.001), while patients in group 2 presented more often with growth concerns (21% versus 68%; P < 0.001). At diagnosis, serum aTTG level was consistently lower in group 1 compared with group 2 (367 IU/mL versus 834 IU/mL; P = 0.030). Both groups reported symptom improvement at six months and one year. At the end of one year, aTTG level was more likely to be normal in group 1 compared with group 2 (64% versus 29%; P < 0.001). CONCLUSION: Although they represent a minority group, South Asian children comprised a significant proportion of CD patients presenting to a Canadian celiac clinic. South Asian children were more likely to present with growth concerns, which has important implications for timely diagnosis in this population. In addition, the apparent delay in normalization of aTTG levels suggests that careful follow-up and culturally focused education supports should be developed for South Asian children with CD.

Patient and parent satisfaction with a dietitian- and nurse- led celiac disease clinic for children at the Stollery Children's Hospital, Edmonton, Alberta.

OBJECTIVE: To assess patient and parent satisfaction with a primarily nurse- and dietitian-led celiac disease clinic in a tertiary pediatric centre. METHODS: An online survey was sent to families and patients attending the Stollery Children's Hospital's Multidisciplinary Pediatric Celiac Clinic (Edmonton, Alberta) since 2007. The survey focused on clinic attendance, satisfaction with clinic structure, processes, and education and preference for alternatives to the current process. Respondents were asked to rank satisfaction or preference on a five-point Likert scale, with 1 being lowest and 5 being highest. RESULTS: Most satisfaction related to follow-up with serology (4.6) and with a dietitian (4.3). The most preferred changes included either meeting the entire multidisciplinary team after the biopsy (4.7), or meeting with only the dietitian and nurse after the biopsy (4.4). The preferred education resources were the Internet (4.3) and the dietitian (4.2). The mean overall satisfaction score of the Multidisciplinary Pediatric Celiac Clinic was 4.0. CONCLUSIONS: Results of the present survey suggested that patients and families value a multidisciplinary follow-up clinic for children with celiac disease. In particular, feedback based on repeat blood work and regular contact with a dietitian were highly valued. The present survey, outlining the most valued aspects of the clinic, may be useful for service delivery in other regions. In addition, it provides information on how to better support pediatric patients with celiac disease.

Angiogenic remodeling in pediatric EoE is associated with increased levels of VEGF-A, angiogenin, IL-8, and activation of the TNF-α-NFκB pathway.

OBJECTIVES: Eosinophilic esophagitis (EoE) is a clinicopathologic diagnosis characterized by inflammation and infiltration of eosinophils at the esophageal mucosa. The underlying etiology of EoE remains elusive. Inflammatory diseases, such as asthma, are associated with structural remodeling of the airways, which includes angiogenesis. The aims of this study were to determine the angiogenic profile of esophageal mucosa in children presenting with EoE and to evaluate the putative mechanism(s) underlying the early inflammatory angiogenic response observed in EoE. METHODS: Endoscopically obtained biopsy samples from 18 EoE and 18 control pediatric patients were analyzed for angiogenic markers (CD31, von Willebrand factor, vascular cell adhesion molecule-1) and tissue levels of angiogenic factors (vascular endothelial growth factor [VEGF]-A, VEGF-R2, angiogenin and interleukin [IL]-8). Expression levels of angiogenic factors and markers in EoE and control samples were characterized by immunofluorescence analysis and quantitative reverse transcriptase-polymerase chain reaction. Vascular density of biopsy samples was evaluated by immunofluorescence analysis. RESULTS: Samples from patients with EoE exhibited higher levels of von Willebrand factor, CD31, and vascular cell adhesion molecule-1, which is suggestive of neovascularization and an activated endothelium. Moreover, EoE biopsies showed greater levels of the angiogenesis promoters VEGFA, angiogenin, and IL-8. Interestingly, there were greater cellular levels of tumor necrosis factor-α in EoE samples compared with controls. Furthermore, there were higher nuclear levels of p50 and p65 subunits of NFκB and lower cellular levels of the inhibitor of NFκB, IκB-α, in EoE samples compared with controls. CONCLUSIONS: We demonstrate increased angiogenesis in the esophageal mucosa of pediatric patients with EoE. The data also provided evidence that the angiogenic factors VEGF-A, angiogenin, and IL-8 were prominently involved in promoting angiogenic remodeling.

Muscle weakness in a girl with autoimmune hepatitis and Graves' disease.

Autoimmune hepatitis (AIH) is a chronic hepatic autoimmune disease of unknown etiology associated with inflammatory changes and autoantibodies. The combination of AIH, Grave's disease, and myasthenia gravis (MG) is rare, with only one other case reported. We report a pediatric patient with AIH type 2 and Grave's disease who developed MG whilst on a treatment with corticosteroids. A 13-year-old girl, diagnosed with thyrotoxicosis, was identified as having AIH type 2. During the course of her therapy, she developed muscle weakness. Investigations revealed increased anti-acetylcholine receptor (AChR) antibodies and her electromyography (EMG) was characteristic for MG. Her course is described here. This case highlights the importance of investigating muscle weakness in severely ill hospitalized patients.

The prevalence of long bone fractures in pediatric inflammatory bowel disease.

INTRODUCTION: The association of inflammatory bowel disease (IBD) with decreased bone mineral density is well recognized. In the adult population, up to 50% of IBD patients are reported to have osteopenia, correlating with an increase in the incidence of fractures as compared with controls. The aim of this study was to determine the prevalence of fractures in a pediatric population with IBD as compared with healthy sibling controls (SC). PATIENTS AND METHODS: The families of 209 patients with IBD were sent a questionnaire asking them to compare their children with IBD to a healthy sibling (non-IBD). RESULTS: Surveys were returned by 132 of the 209 families (63%). The sample characteristics of this sample closely resembled the overall clinic population for age (mean 14.3 vs 14.7 years), gender (53% vs 59% male) and diagnosis (58.1 vs 57.8 Crohn disease). Completed surveys described 263 children. Of the 132 with IBD 73 (55%) had Crohn disease, 52 (39%) had ulcerative colitis and 7 (6%) had indeterminate colitis. There were 76/132 males (age range, 4-18 years) with IBD and 64/131 males (age range, 1-26 years) in the sibling controls. Mean ages of the IBD sample 14.3 +/-.3 was compared with 13.9 +/- in SC. Of the total group, 73/263 (28%) reported ever having a fracture, 44 (60%) were siblings (SC), and 29 (40%) had IBD. Of the 29 children with IBD, 17 (59%) reported having a fracture after diagnosis including 2 who had fractures both before and after diagnosis. The total number of fractures reported was 96 (55 SC:41 IBD). CONCLUSION: In this survey, we found no statistically significant difference in the prevalence of fracture in IBD patients compared with their normal siblings.

Effects of chronic, rapid right atrial pacing on cardiac hemodynamics and myofibrillar ATPase activity in piglets.

OBJECTIVES: To determine whether chronic, rapid right atrial pacing in newborn neonatal piglets has any effects on cardiac hemodynamics, and whether these changes are associated with intrinsic alterations in cardiac contractile potential as shown by cardiac myofibrillar calcium ATPase activity. BACKGROUND: Although many studies have examined aspects of heart function in models of supraventricular tachycardia, far less is known about its effects in neonatal animals. It is thought that rapid pacing induces a dilated cardiomyopathy in immature pigs. ANIMALS AND METHODS: Two-week-old piglets underwent rapid right atrial pacing (250 beats/min) for 10 days, and their cardiac hemodynamic response was monitored. To obtain subcellular mechanistic information regarding systolic dysfunction, cardiac myofibrils were isolated and calcium adenosine triphosphatase activity was measured. RESULTS: Control piglets had a heart rate of 185 beats/min at the end of the experimental period. Pulmonary artery flow, pulmonary artery flow index and left ventricular end-diastolic diameter were unchanged as a function of rapid, chronic right atrial pacing. Aortic pressure decreased in the paced piglets. Left atrial pressure increased approximately threefold in the paced animals. Left ventricular end-systolic diameter was also significantly higher after pacing, but left ventricular end-diastolic diameter was unchanged. Left ventricular shortening fraction was depressed approximately 50%. Myofibrillar calcium adenosine triphosphatase activity was significantly depressed as a function of pacing. CONCLUSIONS: Neonatal piglets undergoing chronic supraventricular tachycardia exhibit systolic dysfunction in the absence of dilation. The depression in contractile protein calcium adenosine triphosphatase activity provides information at a subcellular level regarding the mechanism responsible for this cardiomyopathy.