Pediatrics

Background Procedural sedation and analgesia (PSA) is frequently required to perform closed reductions for fractures and dislocations in children. Intravenous (IV) ketamine is the most commonly used sedative agent for closed reductions. However, as children find IV insertion a distressing and painful procedure, there is need to identify a feasible alternative route of administration. There is evidence that a combination of dexmedetomidine and ketamine (ketodex), administered intranasally (IN), could provide adequate sedation for closed reductions while avoiding the need for IV insertion. However, there is uncertainty about the optimal combination dose for the two agents and whether it can provide adequate sedation for closed reductions. The Intranasal Dexmedetomidine Plus Ketamine for Procedural Sedation (Ketodex) study is a Bayesian phase II/III, non-inferiority trial in children undergoing PSA for closed reductions that aims to address both these research questions. This article p...

Background The brainegut axis is a key regulator of normal intestinal physiology; for example, psychological stress is linked to altered gut barrier function, development of food allergies and changes in behaviour. Whether intestinal events, such as enteric bacterial infections and bacterial colonisation, exert a reciprocal effect on stressassociated behaviour is not well established. Objective To determine the effects of either acute enteric infection or absence of gut microbiota on behaviour, including anxiety and non-spatial memory formation. Methods Behaviour was assessed following infection with the non-invasive enteric pathogen, Citrobacter rodentium in both C57BL/6 mice and germ-free Swiss-Webster mice, in the presence or absence of acute water avoidance stress. Whether daily treatment with probiotics normalised behaviour was assessed, and potential mechanisms of action evaluated. Results No behavioural abnormalities were observed, either at the height of infection (10 days) or following bacterial clearance (30 days), in C rodentium-infected C57BL/6 mice. When infected mice were exposed to acute stress, however, memory dysfunction was apparent after infection (10 days and 30 days). Memory dysfunction was prevented by daily treatment of infected mice with probiotics. Memory was impaired in germ-free mice, with or without exposure to stress, in contrast to conventionally reared, control Swiss-Webster mice with an intact intestinal microbiota. Conclusions The intestinal microbiota influences the ability to form memory. Memory dysfunction occurs in infected mice exposed to acute stress, while in the germ-free setting memory is altered at baseline.

Background. Delayed growth is a wellestablished feature of pediatric Crohn's disease. Several factors have been shown to affect growth, including disease location, severity, and treatment. The recently discovered NOD2 gene has been correlated to ileal location of Crohn's disease and subsequently could affect growth through the resulting phenotype or as an independent risk factor. The aim of our study was to determine if growth retardation is affected by genotype independently of disease location or severity.

Ras association domain family protein 1A (RASSF1A) is a tumor suppressor gene silenced in cancer. Here we report that RASSF1A is a novel regulator of intestinal inflammation as Rassf1a(+/-) , Rassf1a(-/-) and an intestinal epithelial cell specific knockout mouse (Rassf1a (IEC-KO) ) rapidly became sick following dextran sulphate sodium (DSS) administration, a chemical inducer of colitis. Rassf1a knockout mice displayed clinical symptoms of inflammatory bowel disease including: increased intestinal permeability, enhanced cytokine/chemokine production, elevated nuclear factor of kappa light polypeptide gene enhancer in B-cells (NFκB) activity, elevated colonic cell death and epithelial cell injury. Furthermore, epithelial restitution/repair was inhibited in DSS-treated Rassf1a(-/-) mice with reduction of several makers of proliferation including Yes associated protein (YAP)-driven proliferation. Surprisingly, tyrosine phosphorylation of YAP was detected which coincided with increased n...

the pathogenesis of chronic inflammatory bowel diseases (IBD, including Crohn disease and ulcerative colitis) is well established. However, the mechanisms by which bacteria lead to intestinal injury in IBD remain unclear and are the focus of current research. Using adherentinvasive Escherichia coli (AIEC) strain LF82, which is linked to Crohn disease, we recently demonstrated the ability of these intestinal microbes to disrupt the integrity of epithelial cells in an in vitro cell model. This disruption provides the bacteria a capacity to penetrate into and beyond the epithelial monolayer, replicate in cells, disseminate within the host, and induce a chronic immune response. These findings provide a link between microbes related to IBD, disruption of the intestinal epithelial cell barrier, and disease pathogenesis.

Background Recurrence following abdominal surgery in Crohn disease is over 50%. The impact of genetics on postoperative recurrence is not well defined. Methods A literature search was conducted where inclusion required an assessment, by genotype, of postoperative recurrence. The primary endpoint was odds of surgical recurrence. Results Twenty-eight studies identified a total of 6715 patients. Thirteen loci were identified as modifying the risk of recurrence. NOD2 was identified as a risk factor for recurrence by multiple works (cumulative odds ratio: 1.64, P = 0.003). Conclusions A NOD2 risk allele is associated with recurrence following surgery in Crohn disease. Progress in this area will require standardized reporting in future works.

Background Although bacteria are implicated in the pathogenesis of chronic inflammatory bowel diseases (IBD), mechanisms of intestinal injury and immune activation remain unclear. Identification of adherent-invasive Escherichia coli (AIEC) strains in IBD patients offers an opportunity to characterize the pathogenesis of microbial-induced intestinal inflammation in IBD. Previous studies have focused on the invasive phenotype of AIEC and the ability to replicate and survive in phagocytes. However, the precise mechanisms by which these newly identified microbes penetrate the epithelial lining remain to be clarified. Therefore, the aim of this study was to delineate the effects of AIEC, strain LF82 (serotype O83:H1) on model polarized epithelial monolayers as a contributor to intestinal injury in IBD. Results Infection of T84 and Madin-Darby Canine Kidney-I polarized epithelial cell monolayers with AIEC, strain LF82 led to a reduction in transepithelial electrical resistance and increas...

Owing to the lack of large randomized controlled studies, which would produce level 1 evidence, to guide management of gastrointestinal disorders in children, data are often extrapolated from adult studies to aid in treatment strategies. However, there are unique aspects to the management of children and adolescents with these chronic diseases, including issues of growth, side effects, long-term outcomes and psychosocial factors that might not be considered in adult trials. There is a major need for increased research in this population. In the future, a better understanding of the pathophysiologic mechanisms of these diseases should guide the development of rational novel therapies with better safety profiles for children with gastrointestinal disorders.

Campylobacter jejuni is the most common bacterial cause of enterocolitis in humans, leading to diarrhoea and chronic extraintestinal diseases. Although probiotics are effective in preventing other enteric infections, beneficial microorganisms have not been extensively studied with C. jejuni. The aim of this study was to delineate the ability of selected probiotic Lactobacillus strains to reduce epithelial cell invasion by C. jejuni. Human colon T84 and embryonic intestine 407 epithelial cells were pretreated with Lactobacillus strains and then infected with two prototypic C. jejuni pathogens. Lactobacillus helveticus, strain R0052 reduced C. jejuni invasion into T84 cells by 35-41%, whereas Lactobacillus rhamnosus R0011 did not reduce pathogen invasion. Lactobacillus helveticus R0052 also decreased invasion of one C. jejuni isolate (strain 11168) into intestine 407 cells by 55%. Lactobacillus helveticus R0052 adhered to both epithelial cell types, which suggest that competitive exclusion could contribute to protection by probiotics. Taken together, these findings indicate that the ability of selected probiotics to prevent C. jejuni-mediated disease pathogenesis depends on the pathogen strain, probiotic strain and the epithelial cell type selected. The data support the concept of probiotic strain selectivity, which is dependent on the setting in which it is being evaluated and tested.

overweight and obese patients. Methods: A cross-sectional study was performed in a consecutive sample of over-weighted adult patients attending to a single hospital for nutritional counseling between February and April 2009. All patients were submitted to: a) clinical questionnaire addressing personal (including GI symptoms); family data and previous knowledge on cancer risk factors; b) QoL assessment through EQ5D and c) a specific questionnaire asking participants to mention their perception of an increased risk and to estimate their own relative risk when compared to an individual with normal BMI. Results: Participants description (n=100): With a median age of 36 years old (min=16, max=64), 82% were women; 33 % were obese (BMI>30); 46% refer GI complains; 42% refer family history of cancer; only 6% had previously received information on cancer risk factor (but 35% mention they knew CCR risk factors identifying in obesity as a risk factor). Median QoL was 75 (p25=57; p75=80). Nine percent misperceived their current BMI. Perception of risk for CRC: For 62% of participants, their own current BMI status did not confer any increased risk for CRC. Also for half (48%) of patients their BMI status will not lead to an increased risk during lifetime. For 39 % an increased risk was accurately estimated as varying from 2 (34%) and 5 (5%). Patients that accurately consider themselves at a higher risk tend to be older patients (p=0,022), with GI complains (p=0,035) and those with familial cancer history (p=0,017, respectively), but with inaccurate risk estimation. No differences were found between gender, knowledge of risk factors, BMI status (overweight vs obese) or BMI misperception and current health status. Main Limitations: Hospital based small size sample of patients. Conclusions: Only a third of patients seem to adequately consider their own overweight as a potential risk for colorectal cancer during lifetime. Health education programs concerning obesity must include GI cancer as a potential outcome for over weighted patients

Background: Ileal lesions in Crohn disease patients are colonized by adherent-invasive Escherichia coli (AIEC), which are able to invade and replicate within intestinal epithelial cells. The mechanisms by which AIEC exerts its pathogenic effects are not understood. Interferon gamma (IFN-γ) is an important cytokine involved in the host innate defence, which signals through signal transducer and activator of transcription 1 (Stat1). Previous studies have shown that other gastrointestinal pathogens block Stat1 phosphorylation as a means of subverting the host innate immune response. AIM: To determine if AIEC blocks STAT1 signalling in order to evade the host immune response. Methods: Intestine 407 cells were infected for 6 hr with AIEC, strain LF82 (serotype O83:H1) or other pathogenic and commensal Escherichia coli strains as positive and negative controls, respectively. To asses activation of Stat1, epithelial cells were stimulated with IFN-γ (50ng/ml) for 30 min after infection and tyrosine phosphorylation was monitored by immunoblotting. Results: AIEC strain LF82 and enterohemorrhagic E. coli O157:H7, but not E. coli commensal strain HB-101 or enteropathogenic E. coli strain E2348/69 (O127:H6), blocked Stat1 phosphorylation in intestinal epithelial cell lines after stimulation with IFN-γ. Preliminary studies indicate that the inhibitory factor was secreted into culture medium, was dependent on the presence of live bacteria, and required intact bacterial protein synthesis machinery. Conclusions: Suppression of host epithelial cell IFN-γ signalling by a secreted factor produced by AIEC strain LF82 could represent a novel mechanism by which this pathogen evades the host innate immune system, and thereby may explain a predisposition to chronic inflammation in Crohn disease.

Aim: 30% of patients hospitalized with severe UC prove steroid-refractory. We aimed to evaluate outcomes and predictors of response to infliximab as rescue therapy in severe pediatric UC. Methods: As part of a prospective multicenter study, we evaluated factors associated with immediate and 1-year response to infliximab in steroid-refractory severe pediatric UC. Data were recorded at admission, days 3 and 5, at introduction of infliximab, at discharge and 1-year thereafter, using standardized data collection forms. Disease activity was determined using the validated Pediatric UC Activity Index (PUCAI). Serum TNF alpha level was determined before infliximab treatment using a cytokine antibody panel (TransSignal, CA). Concurrently, fecal calprotectin and lactoferrin levels were ascertained using standard assays in a central laboratory. Results: Of 128 children admitted, 33 failed steroids and treated with infliximab within 10.5±6 days. Mean PUCAI score at introduction of infliximab was 66±13 points, indicating persistence of severe colitis. 25/33 children (76%) responded and were discharged within 5±4 days of infliximab therapy; 7 in complete clinical remission (PUCAI<10 points), and 18 with mild disease (PUCAI<35 points). All 8 nonresponders had new-onset disease vs. 10 (40%) of the responders (P=0.03). Similarly, disease duration was shorter for the non-responders (median 0.5 months (IQR 0-3)) than for responders (5.4 months (3.4-18); P=0.015). Non-responders had higher disease activity at admission and during the subsequent three days(P=0.02). Responders and non responders did not differ in age, disease duration, steroid dosing, or admission length prior to infliximab (all P>0.2). CRP, ESR, albumin and hemoglobin were not predictive of response to infliximab. Neither fecal calprotectin nor lactoferrin values were predictive of response (area under ROC curve 0.61 and 0.63, respectively; P>0.2). Serum TNF-alpha level was similar between responders and non-responders (10.6pg/ml (IQR 4-30) vs. 8.3pg/ml (5.7-11); P=0.4). 8 of the 25 responders received only 3-dose induction, and the others continued maintenance therapy without concomitant immunomodulation. Cumulative 1-year sustained response rate was 55% (18/33). There were no deaths and only 1 patient stopped treatment due to infusion reaction. Conclusion: Infliximab is safe and effective in inducing and maintaining clinical remission in steroid-refractory pediatric UC. Serum TNF-alpha level and fecal biomarkers are not useful in predicting outcome, but higher disease severity, judged clinically, and new onset disease are associated with reduced response.

Background-Although the role of microbes in disease pathogenesis is well established, data describing the variability of the vast microbiome in children diagnosed with ulcerative colitis (UC) are lacking. This study characterizes the gut microbiome in hospitalized children with severe UC and determines the relationship between microbiota and response to steroid therapy. Methods-Fecal samples were collected from 26 healthy controls and 27 children hospitalized with severe UC as part of a prospective multi-center study. DNA extraction, PCR amplification of bacterial 16S rRNA, and microarray hybridization were performed. Results were analyzed in Genespring GX 11.0 comparing healthy controls to children with UC, and steroid responsive (n=17) to non-responsive patients (n=10). Results-Bacterial signal strength and distribution showed differences between UC and healthy controls (adjusted p<0.05) for Phylum, Class, Order, Family, Genus, and Phylospecies levels with reduction in Clostridia and an increase in Gamma-proteobacteria. The number of microbial phylospecies was reduced in UC (266±69) vs. controls (758±3, p<0.001), as was the Shannon diversity index (6.1±0.23 vs. 6.49±0.04, respectively; p<0.0001). Steroids non-responders harbored less phylospecies than responders (142±49 vs. 338±62, p=0.013). Conclusions-Richness, evenness, and biodiversity of the gut microbiome were remarkably reduced in children with UC, compared to healthy controls. Children who did not respond to steroids harbored a microbiome that was even less rich than steroid responders. This study is the first to characterize the gut microbiome in a large cohort of pediatric patients with severe ulcerative colitis and describes changes in the gut microbiome as a potential prognostic feature.

The health impacts of air pollution have received much attention and have recently been subject to extensive study. Exposure to air pollutants such as particulate matter (PM) has been linked to lung and cardiovascular disease and increases in both hospital admissions and mortality. However, little attention has been given to the effects of air pollution on the intestine. The recent discovery of genes linked to susceptibility to inflammatory bowel diseases (IBD) explains only a fraction of the hereditary variance for these diseases. This, together with evidence of increases in incidence of IBD in the past few decades of enhanced industrialization, suggests that environmental factors could contribute to disease pathogenesis. Despite this, little research has examined the potential contribution of air pollution and its components to intestinal disease. Exposure of the bowel to air pollutants occurs via mucociliary clearance of PM from the lungs as well as ingestion via food and water sources. Gaseous pollutants may also induce systemic effects. Plausible mechanisms mediating the effects of air pollutants on the bowel could include direct effects on epithelial cells, systemic inflammation and immune activation, and modulation of the intestinal microbiota. Although there is limited epidemiologic evidence to confirm this, we suggest that a link between air pollution and intestinal disease exists and warrants further study. This link may explain, at least in part, how environmental factors impact on IBD epidemiology and disease pathogenesis.

Background and aim: Approximately one third of patients with acute severe ulcerative colitis (ASC) will fail intravenous corticosteroids (IVCS). Predicting response to IVCS to initiate early salvage therapy remains challenging. The aim of this study was to evaluate the role of serum inflammatory cytokines in ASC and determine their predictive utility with IVCS treatment failure. Methods: This preplanned ancillary study, part of the prospective multicenter OSCI study, evaluated pediatric ASC in North America. Serum samples were obtained from 79 children admitted for ASC on the third day of IVCS treatment. Twenty-three (29%) patients required second-line therapy.

Background. Intestinal bacterial infections are a major cause of morbidity and mortality, especially in neonates. Therefore, the aims of this study were to characterize Citrobacter rodentium infection in neonatal mice and determine the role played by specific probiotics in ameliorating disease severity. Methods. Infection of C57BL/6 mice with C. rodentium was performed at postnatal day 14. A subset of mice was pretreated orally with either a mixture of Lactobacillus rhamnosus and Lactobacillus helveticus or placebo, starting at 7 days. To study the effects of B and T cells, rag1 Ϫ/Ϫ and JH Ϫ/Ϫ mice were used, with survival, colonic crypt depth, and barrier function evaluated as outcome measures. Results. C. rodentium infection caused weight loss and death. In contrast, survival was maintained by daily treatment with Lactobacilli. Weight loss, colonic epithelial cell hyperplasia, mucosal barrier dysfunction, and elevated serum corticosterone levels in C. rodentium-infected wild-type mice were ameliorated by probiotics, but not in rag1 Ϫ/Ϫ animals. Beneficial effects of probiotics were observed in B cell-deficient (JH Ϫ/Ϫ ) mice, indicating the requirement of T cells in reducing the adverse sequelae of neonatal enteric infection. Conclusions. These findings demonstrate that C. rodentium infection in newborn mice causes death and that probiotics promote survival, but only in the presence of T cells. Disease burden caused by bacterial pathogens, including enterohemorrhagic Escherichia coli O157:H7 (EHEC), is considerable . EHEC is linked to both food-and water-borne outbreaks and adverse systemic sequelae, including hemorrhagic colitis and hemolytic uremic syndrome . As with other pathogens, young, elderly, and immune-compromised individuals are at increased risk of developing systemic complications after EHEC infection . Currently, no therapy has proven efficacious in reducing disease burden of EHEC, and con-