A47 SYNTHETIC HUMAN MILK OLIGOSACCHARIDES PREVENT EXPERIMENTAL NECROTIZING ENTEROCOLITIS VIA DIVERGENT TRANSCRIPTOMIC RESPONSES

Background

Breastmilk reduces the risk of necrotizing enterocolitis (NEC) in preterm infants, but the bioactive components mediating this effect are not well understood. Human milk oligosaccharides (HMOs) reduce NEC both in humans and in relevant animal models. However, it is unclear if there are functional differences between individual oligosaccharides.

Aims

The objective of this study was to compare the intestinal transcriptome responses of individual HMOs using complementary in vitro and in vivo models of NEC.

Methods

RNA sequencing was performed on Caco-2Bbe1 gut epithelial cells after exposure to commercially-purified 2’-fucosyllactose (2’FL), 3-fucosyllactose, 6’-siallyllactose, lacto-N-tetraose (LNT) or lacto-N-neotetraose for 24hr at 37°C for 24 h (n=3). Signaling pathways were analyzed in murine- and human-derived NEC enteroids by qPCR. To validate these findings, five-day-old mouse pups were orally gavaged formula with or without individual HMOs, followed by NEC induction with hypoxia (5% O2, 95% N2) and lipopolysaccharide (4 mg/kg/day). Coded ileal sections (n=6–7/group) were analyzed for mucosal injury by histology, immune fluorescence, immunohistochemistry, and gene expression via qPCR.

Results

The HMO transcriptome clustered into divergent functional categories including metabolic process, protein processing and responses to external stimuli. Each synthetic HMO induced a unique transcriptome and exhibited varying effects on the intestinal epithelial functions and biological pathways. This was confirmed in the murine model of NEC, as both LNT and 2FL mitigated NEC injury with comparable recovery of intestinal cell proliferation (Ki67) and expression of stem cells (Lgr5+). Both qPCR and immunofluorescence staining showed differences between 2FL- and LNT-fed pups in host inflammatory and immune responses.

Conclusions

This study demonstrates that synthetic HMOs ameliorate intestinal injury in experimental NEC. However, the mechanisms by which individual oligosaccharides act on the intestine differ, suggesting that single synthetic HMOs may not fully recapitulate the benefits of pooled HMOs. Future studies will further delineate structure-function relationships of synthetic HMOs on host intestinal innate and adaptive immune responses.

Funding Agencies

CIHRFerring Canada Medical Student Research grant

A1 F4/80+LY6CHI MACROPHAGES ARE KEY TO CANCER INITIATION IN COLITIS

Background

Colorectal cancer (CRC) is the third leading cause of cancer death, with a major risk factor being chronic inflammation. Thus, patients with inflammatory bowel disease (IBD) are at an increased risk of CRC. Despite the clear association between inflammation and cancer, the mechanism by which colitis leads to CRC is still not well understood.

Aims

In this study, we aim to explore the mechanism by which inflammation contributes to the initiation of colitis-associated cancer (CAC). We hypothesize that dextran sodium sulfate (DSS)-induced colitis leads to the infiltration of a specific immune cell type associated with tumorigenesis.

Methods

Following an injection of azoxymethane (AOM), mice were treated with the colitis-inducing agents DSS, trinitrobenzene sulfonic acid (TNBS), oxazolone (oxa), Citrobacter rodentium, or Doxorubicin (Doxo). The tumor studies were repeated using our published Cre-dependent murine model of CAC. To generate tamoxifen-inducible Cre transgenic mice that allow for Dclk1+ cell lineage tracing and cell-specific knock-out of the tumor suppressor adenomatous polyposis coli (APC), we crossed our Dclk1CreERT2 mice to both ROSA26tdTomato and APCfl/fl mice (Dclk1/APCfl/fl).

Results

Treatment with DSS, TNBS, oxa, C. rodentium, or Doxo induced colonic inflammation as detected by increased myeloperoxidase (MPO) activity and histologic analysis. DSS administration led to colonic tumors, whereas TNBS, oxa, C. rodentium, or Doxo did not lead to tumorigenesis up to 52 weeks following colitis induction. Upon flow cytometric analysis of several types of immune cells in the colonic tissue, we observed no difference in the number of T and B cells between mice treated with various colitis inducing agents. We did, however, detect significantly increased levels of Ly6G+ neutrophils and F4/80+Ly6Chi macrophages in the DSS-treated mice when compared to mice in the other models of colitis. mRNA and protein array analyses of the colonic tissue, as well as analysis of the RNA-seq data from 206 UC patients (GSE109142), revealed upregulated expression of genes associated with macrophages and neutrophils. Addition of macrophage-produced cytokines, such as IL-1β, TNF-α, or IL-6, induced lineage tracing of Dclk1+ tuft cells in intestinal organoids. Clodronate liposome-mediated depletion of F4/80+Ly6Chi macrophages significantly reduced the number of colonic tumors but did not affect tumor size in Dclk1/APCfl/fl mice.

Conclusions

Our data suggest that infiltration of F4/80+Ly6Chi macrophages, unique to DSS-induced colitis, leads to colonic tumor formation. This demonstrates that specific immune cell types, rather than the presence of colonic inflammation, plays an important role in the initiation of CAC.

Funding Agencies

CAG, CIHR

A103 PROBIOTIC FORMULATIONS DIFFERENTIALLY AFFECT DISEASE OUTCOME IN A MOUSE MODEL OF NECROTIZING ENTEROCOLITIS

Background

Necrotizing enterocolitis (NEC) causes severe gastrointestinal disease in premature infants. A precise etiology is not yet known, but it is generally agreed that intestinal immaturity & alterations in the gut microbiota play key roles in NEC progression. There is growing interest in the clinical use of probiotics for the prevention of NEC in at-risk infants. Some probiotics, which are defined as beneficial bioactive microbes that provide a health benefit when administered in sufficient amounts, may influence disease outcome in premature infants with NEC.

Aims

To investigate the efficacy of two commercially available probiotic formulations, Lacidofil® and ProBiokid®, in the prevention of experimentally-induced NEC.

Methods

At gestational day 12.5, treated dams were administered probiotics (109 cfu/mL) in drinking water (Table 1). NEC was induced at postnatal day 5 or when pups were ≥ 3.0 g by the administration of hyperosmolar formula, hypoxia, and lipopolysaccharide (4 mg/kg). NEC pups receiving probiotics were administered 108cfu in hyperosmolar formula once daily during the morning feeding. Body weight, survival and disease severity were scored.

Results

Neither probiotic intervention affected overall survival of NEC-induced pups. Control dam-fed pups (NN) continued to gain weight as expected over time, while untreated NEC pups (NNNEC) exhibited a significant delay in weight gain. LLNEC pups exhibited the greatest percent body weight increase over time, possibly due to a lower birth weight. Lacidofil administration did not improve NEC-induced tissue damage irrespective of the timing of intervention. In contrast, Probiokid provided to both dam and pups (PPNEC) resulted in less severe tissue damage compared to their control counterparts.

Conclusions

These finding demonstrate strain-specific differences in two different commercial probiotic formulations in the prevention of NEC in newborn mice. Future studies seek to provide insight into how Lacidofil and Probiokid engage intestinal stem cells (Lgr5-GFP mice), cell proliferation (Ki67 positivity) and differentiation (MUC2 & Chromogranin A positivity) in the NEC-damaged intestine.

Funding Agencies

CIHRMITACS Accelerate Postdoctoral Award

A16 ROLE OF MYELOID CELLS IN THE INITIATION OF COLITIS-ASSOCIATED COLON CANCER

Background

Colorectal cancer (CRC) is the second leading cause of cancer death, with a major risk factor being chronic inflammation. Despite the clear association between inflammation and cancer, the mechanism by which colitis leads to CRC is not well understood. We recently showed that the presence of inflammation does not always correlate with colonic tumorigenesis, as the type of colitis (i.e. colitis-inducing agent) appears to be important for tumor initiation.

Aims

In this study, we aim to explore the mechanism by which inflammation contributes to the initiation of colitis-associated cancer. We hypothesized that dextran sodium sulfate (DSS)-induced colitis leads to the infiltration of a specific immune cell type that is associated with colonic tumorigenesis.

Methods

To generate tamoxifen-inducible Cre transgenic mice that allow for Dclk1+ cell lineage tracing and cell-specific knock-out of the tumor suppressor adenomatous polyposis coli (APC), we first crossed our transgenic Dclk1CreERT2 mice to both ROSA26tdTomato and APCfl/fl mice (Dclk1/APCfl/fl). Following Tamoxifen induction, mice were treated with the colitis-inducing agents DSS, trinitrobenzene sulfonic acid (TNBS), oxazolone, or Citrobacter rodentium. The tumor studies were repeated using azoxymethane (AOM)-DSS induced colitis-associated cancer model.

Results

Treatment with any of the four colitis-inducing agents (DSS, TNBS, oxazolone, or C. rodentium) induced colonic inflammation as detected by increased myeloperoxidase (MPO) activity and histologic analysis. Interestingly, DSS administration led to colonic tumors, whereas TNBS, oxazolone, or C. rodentium did not, even up to 52 weeks following colitis induction. FACS analysis of immune cells in the colon revealed no difference in the number of T or B cells in mice treated with any of the colitis-inducing agents. We did, however, detect significantly increased levels of Ly6G+ neutrophils and F4/80+ macrophages in DSS-treated mice compared to mice in any of the other three models of colitis. Consistent with this myeloid cell infiltration, significantly upregulated protein levels of G-CSF, IL-6, TNF-α, and CXCL1 were detected in DSS-treated mice compared to the other three models of colitis. IL-1α, IL-1β, IL-4, IL-10, and TGF-β levels were unchanged.

Conclusions

Our data suggest that infiltration of Ly6G+ neutrophils and pro-inflammatory F4/80+ macrophages, unique to DSS-induced colitis, contributes to colonic tumor formation. These data demonstrate that specific immune cell types, rather than the presence of colonic inflammation, play a critical role in the initiation of colitis-associated CRC.

Funding Agencies

CAG, CIHR

Immune signalling responses in intestinal epithelial cells exposed to pathogenic Escherichia coli and lactic acid-producing probiotics

Enterohaemorrhagic Escherichia coli O157:H7 and adherent-invasive Escherichia coli are two groups of enteric bacterial pathogens associated with haemorrhagic colitis and Crohn's Disease, respectively. Bacterial contact with host epithelial cells stimulates an immediate innate immune response designed to combat infection. In this study, immune responses of human epithelial cells to pathogens, either alone or in combination with probiotic bacteria were studied. Industrially prepared Lactobacillus helveticus strain R0052 was first examined by microarray analysis and then compared to broth-grown strains of R0052 and Lactobacillus rhamnosus strain GG using quantitative realt-time polymerase chain reaction. Results showed host immune activation responses increased following pathogen exposure, which were differentially ameliorated using probiotics depending on both the preparation of probiotics employed and conditions of exposure. These findings provide additional support for the concept that specific probiotic strains serve as a promising option for use in preventing the risk of enteric bacterial infections.

Relationship between fractional anisotropy of cerebral white matter and metabolite concentrations measured using (1)H magnetic resonance spectroscopy in healthy adults

Fractional anisotropy (FA) of water diffusion in cerebral white matter (WM), derived from diffusion tensor imaging (DTI), is a sensitive index of microscopic WM integrity. Physiological and metabolic factors that explain intersubject variability in FA values were evaluated in two cohorts of healthy adults of different age spans (N=65, range: 28-50years; and N=25, age=66.6±6.2, range: 57-80years). Single voxel magnetic resonance spectroscopy (MRS) was used to measure N-acetylaspartate (NAA), total choline-containing compounds, and total creatine, bilaterally in an associative WM tract: anterior corona radiata (ACR). FA values were calculated for the underlying, proximal and two distal WM regions. Two-stage regression analysis was used to calculate the proportion of variability in FA values explained by spectroscopy measurements, at the first stage, and subject's age, at the second stage. WM NAA concentration explained 23% and 66% of intersubject variability (p<0.001) in the FA of the underlying WM in the younger and older cohorts, respectively. WM NAA concentration also explained a significant proportion of variability in FA of the genu of corpus callosum (CC), a proximal WM tract where some of the fibers contained within the spectroscopic voxel decussate. NAA concentrations also explained a significant proportion of variability in the FA values in the splenium of CC, a distal WM tract that also carries associative fibers, in both cohorts. These results suggest that MRS measurements explained a significant proportion of variability in FA values in both proximal and distal WM tracts that carry similar fiber-types.

Corticotropin-releasing hormone (CRH) regulates macromolecular permeability via mast cells in normal human colonic biopsies in vitro

OBJECTIVE

Persistent stress and life events affect the course of ulcerative colitis and irritable bowel syndrome by largely unknown mechanisms. Corticotropin-releasing hormone (CRH) has been implicated as an important mediator of stress-induced abnormalities in intestinal mucosal function in animal models, but to date no studies in human colon have been reported. The aim was to examine the effects of CRH on mucosal barrier function in the human colon and to elucidate the mechanisms involved in CRH-induced hyper-permeability.

DESIGN

Biopsies from 39 volunteers were assessed for macromolecular permeability (horseradish peroxidase (HRP), (51)Cr-EDTA), and electrophysiology after CRH challenge in Ussing chambers. The biopsies were examined by electron and confocal microscopy for HRP and CRH receptor localisation, respectively. Moreover, CRH receptor mRNA and protein expression were examined in the human mast cell line, HMC-1.

RESULTS

Mucosal permeability to HRP was increased by CRH (2.8+/-0.5 pmol/cm(2)/h) compared to vehicle exposure (1.5+/-0.4 pmol/cm(2)/h), p = 0.032, whereas permeability to (51)Cr-EDTA and transmucosal electrical resistance were unchanged. The increased permeability to HRP was abolished by alpha-helical CRH (9-41) (1.3+/-0.6 pmol/cm(2)/h) and the mast cell stabilizer, lodoxamide (1.6+/-0.6 pmol/cm(2)/h). Electron microscopy showed transcellular passage of HRP through colonocytes. CRH receptor subtypes R1 and R2 were detected in the HMC-1 cell line and in lamina propria mast cells in human colon.

CONCLUSIONS

Our results suggest that CRH mediates transcellular uptake of HRP in human colonic mucosa via CRH receptor subtypes R1 and R2 on subepithelial mast cells. CRH-induced macromolecular uptake in human colon mucosa may have implications for stress-related intestinal disorders.

The natural history and significance of ultrasonographically defined polypoid lesions of the gallbladder in children

BACKGROUND/PURPOSE

Gallbladder polyps are relatively common in adults and may increase the risk of gallbladder cancer. The increased use of high-quality abdominal ultrasonography has likely led to the increase detection of these lesions in the pediatric population. The aim of the present study was to address the significance of the ultrasonographic finding of a gallbladder polyp in children.

METHODS

This prospective case series of 4 children with ultrasonographically defined gallbladder polyps outlines their presentation and clinical course. A detailed review of the literature and a management approach has been provided.

RESULTS

In the 4 cases, polyps were followed for 2, 5, 72, and 84 months with a clinical follow-up of 7 to 11 years. Three underwent cholecystectomy and only 1 of 3 had a polypoid gallbladder lesion. One child, followed for 7 years, had no change in size, shape, or location of the polyp. This case series adds to the small group of children in the literature with polypoid gallbladder lesions and, to our knowledge, none have developed malignant transformation.

CONCLUSIONS

Clearly more studies on such children are required to further add to our knowledge on the natural history and the appropriate management of these lesions.

Combined challenge of mice with Citrobacter rodentium and ionizing radiation promotes bacterial translocation

PURPOSE

Both enteric infection and exposure to ionizing radiation are associated with increased intestinal permeability. However, the combined effect of irradiation and enteric infection has not been described. We combined infection of mice with the enteric pathogen, Citrobacter rodentium, with exposure to ionizing radiation and assessed the impact on colonic epithelial ion transport, permeability and bacterial translocation.

MATERIALS AND METHODS

Mice were infected with C. rodentium and then received whole-body exposure to 5 Gray gamma-radiation 7 days later. Three days post-irradiation, mice were euthanized and colons removed. Control groups included sham-infected mice that were irradiated and mice that were infected, but not irradiated.

RESULTS

Macroscopic damage score and colonic wall thickness were increased by C. rodentium infection, but these parameters were not exacerbated by irradiation. Infection caused an increase in myeloperoxidase activity that was reduced by irradiation. Irradiation reduced the secretory response to electrical field stimulation, forskolin and carbachol; these changes were not altered by infection with C. rodentium. None of the treatments caused an increase in permeability to 51Cr-ethylenediaminetetraacetic acid (EDTA). However, combined infection and irradiation synergistically increased bacterial translocation to mesenteric lymph nodes, liver, spleen and blood.

CONCLUSIONS

Although the combination of irradiation and infection did not exacerbate the individual effects of these challenges on ion secretion and mucosal permeability to 51Cr-EDTA, it dramatically increased susceptibility to bacterial translocation and bacteremia. These results have important implications for patients who develop an enteric infection during the course of abdominopelvic radiotherapy.

Meta-analysis: Helicobacter pylori eradication treatment efficacy in children

BACKGROUND

Several meta-analyses assessing the efficacy of anti-Helicobacter pylori treatment in adults have been published but a comparable meta-analysis in children is lacking.

AIMS

To summarize the efficacy of treatments aimed at eradicating H. pylori in children and to identify sources of variation in treatment efficacy across studies.

METHODS

We searched Medline, reference lists from published study reports, and conference proceedings for anti-H. pylori treatment trials in children. Weighted meta-regression models were used to find sources of variation in efficacy.

RESULTS

Eighty studies (127 treatment arms) with 4436 children were included. Overall, methodological quality of these studies was poor with small sample sizes and few randomized-controlled trials. The efficacy of therapies varied across treatment arms, treatment duration, method of post-treatment assessment and geographic location. Among the regimens tested, 2-6 weeks of nitroimidazole and amoxicillin, 1-2 weeks of clarithromycin, amoxicillin and a proton pump inhibitor, and 2 weeks of a macrolide, a nitroimidazole and a proton pump inhibitor or bismuth, amoxicillin and metronidazole were the most efficacious in developed countries.

CONCLUSIONS

Before worldwide treatment recommendations are given for eradication of H. pylori, additional well-designed randomized placebo-controlled paediatric trials are needed, especially in developing countries where both drug resistance and disease burden is high.

Probiotics prevent bacterial translocation and improve intestinal barrier function in rats following chronic psychological stress

BACKGROUND AND AIMS

Chronic psychological stress, including water avoidance stress (WAS), induces intestinal mucosal barrier dysfunction and impairs mucosal defences against luminal bacteria. The aim of this study was to determine the ability of a defined probiotic regimen to prevent WAS induced intestinal pathophysiology.

METHODS

Male rats were subjected to either WAS or sham stress for one hour per day for 10 consecutive days. Additional animals received seven days of Lactobacillus helveticus and L rhamnosus in the drinking water prior to stress and remained on these probiotics for the duration of the study. Rats were then sacrificed, intestinal segments assessed in Ussing chambers, and mesenteric lymph nodes cultured to determine bacterial translocation.

RESULTS

All animals remained healthy for the duration of the study. Chronic WAS induced excess ion secretion (elevated baseline short circuit current) and barrier dysfunction (increased conductance) in both the ileum and colon, associated with increased bacterial adhesion and penetration into surface epithelial cells. Approximately 70% of rats subjected to WAS had bacterial translocation to mesenteric lymph nodes while there was no bacterial translocation in controls. Probiotic pretreatment alone had no effect on intestinal barrier function. However, WAS induced increased ileal short circuit current was reduced with probiotics whereas there was no impact on altered conductance. Pretreatment of animals with probiotics also completely abrogated WAS induced bacterial adhesion and prevented translocation of bacteria to mesenteric lymph nodes.

CONCLUSION

These findings indicate that probiotics can prevent chronic stress induced intestinal abnormalities and, thereby, exert beneficial effects in the intestinal tract.

Development of a cavum septi pellucidi after Ommaya reservoir placement: report of an unusual complication

Objective and importance. We present a complication of Ommaya reservoir placement that has not been previously reported. Following injection of a seemingly appropriately placed catheter, the patient developed seizures. Imaging studies showed the development and resolution of a cavum septi pellucidi. This case illustrates that the septum pellucidum is made of two layers and that a potential space exists between these layers. Caution is recommended when injecting a single-hole ventricular catheter if the tip is against the septum pellucidum.

Anastomotic ulceration following small bowel transplantation

We describe, for the first time, anastomotic ulcers (AU) following bowel transplantation at the Hospital for Sick Children. Two children presented with rectal bleeding, 6 and 9 months, following the transplantation. Isolated ulcers were identified at the ileo-colonic and the colo-colonic anastomosis site. The ulcers resolved, but recurred 6 and 7 months after the initial presentation. Both patients were positive for adenovirus in the stool and were treated with rapamycin. The histology revealed granulation tissue formation with mild inflammation in the adjacent mucosa, without evidence of rejection or infection. A literature search revealed 10 studies reporting 29 patients who developed AU following various surgical etiologies, none of which was bowel transplant. Numerous factors that are unique to the post-transplant period may predispose to such ulcer and are discussed in detail. Physicians and surgeons should be aware of this multifactorial complication, among other etiologies, as a cause of anemia or rectal bleeding following intestinal transplantation.

Increased epithelial uptake of protein antigens in the ileum of Crohn's disease mediated by tumour necrosis factor alpha

BACKGROUND AND AIMS

The exact nature of the epithelial barrier defect in Crohn's disease remains to be elucidated. Previously we showed increased permeability to proteins in ileal Crohn's disease. Our aims were to study if this barrier defect (a) involves endocytotic uptake of antigens and (b) is related to low grade inflammation not detectable by histology.

METHODS

Macroscopically normal segments of distal ileum of Crohn's disease patients (n = 10) were subgrouped into non-inflamed (histologically unaffected) and slightly inflamed tissues and studied in Ussing chambers, with normal ileal specimens from colon cancer patients (n = 9) as controls. Endocytotic uptake into enterocytes of the protein antigen horseradish peroxidase was assessed by measuring the area of horseradish peroxidase containing endosomes in electron photomicrographs. Mucosal tumour necrosis factor alpha (TNF-alpha) mRNA was quantified using real time polymerase chain reaction. For comparison, the effects of low doses of TNF-alpha on endosomal uptake of horseradish peroxidase were studied in cultured T84 cells grown on filter supports.

RESULTS

The area of horseradish peroxidase containing endosomes was increased (p<0.001) in enterocytes of non-inflamed ileum of Crohn's disease (2.8 (0.7) mum(2)/300 mum(2)) compared with control ileum (0.6 (0.06)). In non-inflamed mucosa, a significant association between endosomal uptake and mucosal expression of TNF-alpha mRNA (p = 0.03) was found. Low concentrations of TNF-alpha (0.25-1.0 ng/ml) enhanced the endosomal uptake of horseradish peroxidase in polarised T84 cells, without affecting transepithelial electrical resistance.

CONCLUSIONS

Our findings suggest increased endosomal uptake of antigens in ileal Crohn's disease that may be mediated by TNF-alpha. These data highlight the transcellular route of antigen uptake in barrier dysfunction and implicate the interaction between epithelial cells and the innate immune system in the development of mucosal inflammation.

In vivo evaluation of the effects of gravitational force (+Gz) on over-the-wire stainless steel Greenfield inferior vena cava filter in swine

This study was done to determine the effect of exposure to gravitational force (acceleration stress) on in vivo over-the-wire stainless steel Greenfield inferior vena cava filters. Fifteen pigs underwent venous cut down and placement of a stainless steel Greenfield filter. A 4-week observation period simulated realistic convalescence and allowed sufficient time for epithelialization. Ten pigs were exposed to acceleration stress in a centrifuge (3G run for 15 sec followed by rest until return to baseline heart rate, then a 9G run for 15 sec), with inertial loading in a head-to-tail direction (+Gz). Fluoroscopy during acceleration stress allowed assessment for filter migration. Five pigs were not exposed to acceleration stress. AP and lateral abdominal radiographs were obtained at post-filter placement, convalescence, and centrifuge exposure to determine the position and integrity of the filter. All 15 IVCs were resected and evaluated for gross or histological injury to the vessel wall. IVC filter placement was technically successful in all 15 pigs. Radiographic measurements were limited secondary to differences in pig positioning. Fluoroscopy showed no filter migration. All filters were securely attached to the vena cava by the hooks without gross evidence of perforation or hemorrhage. There were varying degrees of fibroplasia involving the hooks and tip of the filters in both the control and experimental groups. Histologically, there was evidence of prior hemorrhage at the level of the hooks, which was similar between the control and experimental groups. It is concluded that Greenfield filter position and vena caval integrity at the implantation site is unaffected by high acceleration stress.

Acetabular paralabral cyst: an uncommon cause of sciatica

The association between tears of the acetabular labrum and paralabral cysts has been well documented, and magnetic resonance imaging (MRI) has been shown to be the most accurate noninvasive method of depicting not only the normal anatomic structures of the hip, but also the common pathologic processes such as labral tears and paralabral cysts. We present the case of an acetabular paralabral cyst that resulted in clinically symptomatic compression of the sciatic nerve.

Current controversies associated with Helicobacter pylori infection in the pediatric population

Helicobacter pylori is a human bacterial gastric pathogen, fulfilling each of Koch's postulates for causal inference for ulceration in children and adults. In addition many reports purport to show that the organism causes a variety of extra-intestinal manifestations in children. This review of the English language literature provides evidence that H. pylori is likely a cause of unexplained iron deficiency (sideropenic) anemia in children, even in the absence of gastrointestinal bleeding. Much stronger evidence is required however, before H. pylori infection can be considered as an etiologic agent in recurrent abdominal pain of childhood, unexplained short stature, protracted diarrhea in pre-schoolers and sudden infant death syndrome.

Inhibition of attaching and effacing lesion formation following enteropathogenic Escherichia coli and Shiga toxin-producing E. coli infection

Enteropathogenic Escherichia coli (EPEC) and Shiga toxin-producing E. coli (STEC) induce cytoskeletal changes in infected epithelial cells. To further characterize host cytosolic responses to infection, a series of specific cell-signaling inhibitors were employed. Initial bacterial adhesion to HEp-2 epithelial cells was not reduced, whereas alpha-actinin accumulation in infected cells was blocked by a phosphoinositide-specific phospholipase C inhibitor (ET-18-OCH3), phosphoinositide 3-kinase inhibitors (wortmannin and LY294002), and a 5-lipoxygenase inhibitor, nordihydroguaretic acid. A cyclooxygenase-2 inhibitor (NS-398), however, did not block alpha-actinin reorganization in response to EPEC and STEC infections. Understanding signal transduction responses to enteric pathogens could provide the basis for the development of novel therapeutic strategies.

MR imaging of the posterior cruciate ligament graft: initial experience in 15 patients with clinical correlation

PURPOSE

To describe the magnetic resonance (MR) appearance of the posterior cruciate ligament (PCL) graft in the 1st postoperative year and to correlate the MR findings with clinical examination findings.

MATERIALS AND METHODS

Nineteen MR examinations were performed in 15 patients (with 15 grafts) 1-33 months after PCL reconstruction. Results of clinical follow-up were available in 14 patients. Graft shape and thickness were recorded, and intrasubstance signal intensity at T2-weighted imaging was graded. The MR findings were correlated with the time between surgery and clinical examination.

RESULTS

At MR imaging, 13 grafts appeared intact, one could not be assessed owing to hardware artifact, and one initially appeared disrupted. Graft thickness was 7-19 mm. There was no significant difference between graft thickness versus time since surgery and signal intensity versus time since surgery (P =.14). In two of three patients who underwent sequential MR examinations, graft thickness and intrasubstance signal intensity decreased as the time between reconstruction and MR imaging increased. Two of 14 patients who underwent physical examination had a posterior drawer, and one also had an anterior cruciate ligament graft tear. Both patients with knee instability demonstrated intact PCL graft fibers at MR imaging. There was no correlation between knee stability and graft thickness, signal intensity, or shape.

CONCLUSION

After PCL reconstruction, MR imaging in the 1st year depicts a thickened graft with increased signal intensity. There does not appear to be a relationship between clinical stability and findings at MR imaging.

Characterization of virulence factors of mouse-adapted Helicobacter pylori strain SS1 and effects on gastric hydrophobicity

Gastric infection with Helicobacter pylori results in chronic active gastritis and in some individuals is associated with complications such as peptic ulceration and gastric cancers. A balance between bacterial factors and host responses may determine disease outcome. The mouse-adapted H. pylori strain SS1 has been utilized as a model to study disease pathogenesis. Although chronic gastritis is observed in this murine model of H. pylori infection, other complications of disease seen in the human host (such as peptic ulceration) are not identified. The objectives of this study were to characterize virulence factors of the mouse-adapted H. pylori strain SS1 and determine host responses to infection. Vacuolating cytotoxin activity of H. pylori strain SS1 was determined after incubation of HEp-2 cells with culture supernatant for 24 hr. Polymerase chain reaction was performed to detect the presence of the cagA and cagE genes. Chemokine responses from human gastric epithelial cells infected with H. pylori SS1 were assessed by measurement of the concentration of interleukin-8 in cell-free supernatants. C57BL/6 and gld mice were infected with strain SS1 or sham-infected. Eight weeks following infection, gastric tissues were obtained for histological analysis and surface hydrophobicity was measured by axisymmetric drop-shape analysis. H. pylori strain SS1 was cytotoxin negative, cagA positive, and cagE positive, but induced only a modest interleukin-8 response (684 +/- 140 pg/ml) from AGS gastric epithelial cells in comparison to a clinical isolate (4170 +/- 410 pg/ml, P < 0.0005). Increased inflammation was observed in the stomachs of H. pylori strain SS1-infected animals compared to uninfected controls. Gastritis was not associated with any disease complications. Despite mucosal inflammation, infected mice did not demonstrate alterations in gastric surface hydrophobicity (42.2 degrees +/- 2.2 degrees and 41.4 degrees +/- 3.2 degrees for C57BL/6 and gld, respectively) compared to uninfected mice (43.2 degrees +/- 2.3 degrees and 39.5 degrees +/- 1.6 degrees, respectively). In conclusion, murine infection with H. pylori SS1, which contains putative bacterial virulence factors, results in gastric inflammation. However, the mucosal changes are not associated with alterations in surface hydrophobicity. Therefore, the mouse model of infection with H. pylori, strain SS1 may not serve as an entirely appropriate model to study host factors associated with disease complications.

Screening for celiac disease in children with recurrent abdominal pain

BACKGROUND

The clinical presentation of celiac disease--a life-long gluten intolerance--may be characterized by chronic abdominal pain. The objective of this study was to determine if children with recurrent abdominal pain had a higher prevalence of antiendomysial antibodies (a serologic marker of celiac disease) compared with healthy children.

METHODS

Children with recurrent abdominal pain and healthy control participants were recruited from the offices of community pediatricians. Serum samples were drawn and antiendomysial antibodies were measured in both groups. Demographic data included age, gender, height, and weight.

RESULTS

A total of 200 children were recruited, of whom 173 (87%) had serum samples drawn. Of these, 92 were children with recurrent abdominal pain and 81 were control participants. Only 2 of the 173 samples (1.2%) were positive for antiendomysial antibody. The frequency of antiendomysial antibody positivity in children with recurrent abdominal pain was 1 in 92 (1%; 95% confidence interval, 0-6%) compared with 1 in 81 (1%; 95% confidence interval, 0-7%) in control participants.

CONCLUSIONS

This community-based case-control study found no association between recurrent abdominal pain and the prevalence of antiendomysial antibody. Therefore, these data do not support screening for celiac disease in the child with classic recurrent abdominal pain in the primary care setting.

Genotypic, clinical, and demographic characteristics of children infected with Helicobacter pylori

Helicobacter pylori isolates vary between geographic regions. Certain H. pylori genotypes may be associated with disease outcome. Thirty-eight children underwent diagnostic upper endoscopy at four medical centers and were retrospectively analyzed to determine if H. pylori virulence genes were associated with endoscopic disease severity, histologic parameters, and host demographics. The H. pylori virulence genotype was analyzed by a reverse hybridization line probe assay and type-specific PCR. Endoscopic ulcers or erosions were found in 17 (45%) patients, with 13 (34%) of these patients having antral nodularity. Histological gastritis, of varying severity, was present in all children. Four patients harbored more than one H. pylori strain: one subject had both cagA(+) and cagA-negative strains, while three patients harbored either two different cagA-negative strains (two children) or two cagA(+) strains (one child). There were 28 (74%) cagA(+) isolates; 19 were associated with the vacA s1b genotype, 7 were associated with the vacA s1a genotype, 1 was associated with the vacA s1c genotype, and 1 was associated with the s2 genotype. Of 14 cagA-negative isolates, 6 were vacA s2 genotype, 4 were vacA s1b, 3 were vacA s1a, and 1 was vacA s1c. Nine of ten (90%) Hispanics had similar H. pylori strains (vacA s1b,m1), and all Asian-Canadian children were infected by strains with vacA s1c genotype. No correlation between H. pylori strain and endoscopic or histopathologic abnormalities was found. This study provides a baseline framework of North American children and their H. pylori strains, serving as a powerful epidemiological tool for prospective investigations to better understand the transmission and evolution of diverse disease outcomes.

Monocyte/macrophage activation by normal bacteria and bacterial products: implications for altered epithelial function in Crohn's disease

Intestinal immune cells are less reactive than those in the peripheral blood; however, such cells from patients with Crohn's disease may be more responsive to bacterial products. Our study examined if nonpathogenic bacteria or lipopolysaccharide (LPS), can affect epithelial function in the presence of monocytes/macrophages. Lamina propria mononuclear cells (LPMCs) and peripheral blood monocytes (PBMs) were obtained from patients with Crohn's disease and control patients. Filter-grown T84 epithelial monolayers were co-cultured with nonactivated or LPS-activated LPMCs or PBMs for 48 hours. Epithelial secretory [baseline short-circuit current (Isc) and DeltaIsc to forskolin] and barrier (transepithelial electrical resistance) parameters were measured in Ussing chambers. LPS-activated PBMs from both controls and patients with Crohn's disease significantly increased Isc ( approximately 300%) and reduced transepithelial electrical resistance ( approximately 40%). Epithelial function was not altered after co-culture with control LPMCs +/- LPS. However, LPMCs from patients with Crohn's disease spontaneously secreted tumor necrosis factor-alpha, and induced epithelial changes similar to those produced by LPS-activated PBMs. Co-culture with control Escherichia coli and PBMs induced comparable changes in epithelial physiology, which were abrogated by anti-tumor necrosis factor-alpha antibody. We conclude that LPMCs of patients with Crohn's disease are spontaneously activated, possibly by gram-negative luminal bacteria, and can directly cause significant alterations in epithelial ion transport and barrier functions.

Implications of antibiotic resistance in the management of Helicobacter pylori infection: Canadian Helicobacter Study Group

Eradication of Helicobacter pylori from the gastric and duodenal mucosa is an important clinical goal in the treatment of infected patients with peptic ulcer disease and other H pylori-associated conditions. Although several oral drug combination regimens are associated with eradication rates of approximately 85% in controlled trials, the success rate in patients infected with a resistant strain of H pylori is closer to 75%. Resistance to metronidazole and clarithromycin, which are common components of combination treatment regimens, is of greatest concern. Reported rates of H pylori resistance to various antibiotics vary considerably. In Canada, the data documenting H pylori susceptibility are limited but suggest that resistance to these antibiotics varies geographically and within specific treatment groups. Although susceptibility testing is not a prerequisite for initial treatment of individual patients infected with H pylori, formal efforts to identify and monitor both the causes and prevalence of antibiotic resistance across Canada are a much needed step in the ongoing management of this important infection. Recommended treatment regimens may be useful, even for treating apparently resistant H pylori strains. However, it is important to understand the mechanisms of the development of resistant strains to manage patients with treatment failure better.

Escherichia coli Shiga toxins induce apoptosis in epithelial cells that is regulated by the Bcl-2 family

Human intestinal cells lack globotriaosylceramide (Gb(3)), the receptor for Shiga toxin-1 (Stx1) and Shiga toxin-2 (Stx2). Therefore, the role of these toxins in mediating intestinal disease during infection with Shiga toxin-producing Escherichia coli is unclear. The aims of this study were to determine whether Stx1 and Stx2 induce apoptosis in epithelial cells expressing (HEp-2, Caco-2) or lacking (T84) Gb(3) and to characterize the role of the Bcl-2 family. Stx1 (12.5 ng/ml) induced apoptosis in both HEp-2 (21.9 +/- 7.9% vs. 0.8 +/- 0.3%, P = 0.01) and Caco-2 (10.1 +/- 1.2% vs. 3.1 +/- 0.4%, P = 0.006) cells but not in Gb(3)-deficient T84 cells. Toxin-mediated apoptosis of HEp-2 cells was associated with enhanced expression of the proapoptotic protein Bax. Inhibition of caspase activation prevented toxin-stimulated apoptosis. In addition, overexpression of Bcl-2 by transient transfection blocked Stx1-stimulated cell death. These findings indicate that Shiga toxins produced by E. coli signal Gb(3)-expressing epithelial cells to undergo apoptosis in association with enhanced Bax expression, thereby resulting in activation of the caspase cascade.

cagE is a virulence factor associated with Helicobacter pylori-induced duodenal ulceration in children

This study was undertaken to determine whether infection with Helicobacter pylori strains that contain the cagE gene was associated with duodenal ulceration in children. The presence of flaA, cagA, and cagE genes was determined by polymerase chain reaction in H. pylori previously cultured from 29 children. Twelve (92%) of 13 children with duodenal ulcers were infected with cagE-positive isolates, compared with only 5 (31%) of 16 with gastritis alone (P<.01). Infection of gastric cells in tissue culture by cagE-positive H. pylori resulted in greater increments in interleukin-8 levels compared with cagE-negative strains (2.3+/-0.1 vs. 1.3+/-0.2 ng/mL in AGS cells [P<.005]; 1.5+/-0.3 vs. 0.5+/-0.2 ng/mL in KATO-III cells [P<.05]). H. pylori-containing cagE was associated with the presence of duodenal ulceration in children. Enhanced chemokine production after infection with cagE-positive H. pylori could affect disease outcome.

Phosphatidylethanolamine recognition promotes enteropathogenic E. coli and enterohemorrhagic E. coli host cell attachment

Using both solid phase and liposome aggregation assays, we screened a variety of glycolipids and phospholipids and found that EHEC and EPEC bind specifically and in a dose-dependent manner to PE. This binding was consistently observed whether the lipid was immobilized on a thin layer chromatography plate, in a microtitre well or incorporated into a unilamellar vesicle suspended in aqueous solution. There was no evidence of binding to other phospholipids such as phosphatidylcholine (PC) or phosphatidylserine (PS). Bacterial binding to two epithelial cell lines also correlated with the level of outer leaflet PE and was reduced following preincubation with anti-PE. The PE-binding phenotype of EPEC appeared to correlate with the bundle-forming pilus (bfp) genotype of a number of clinical isolates. These results provide evidence of a receptor role for PE in the adhesion of EHEC and EPEC to host cells.

Determinants of disease outcome following Helicobacter pylori infection in children

Helicobacter pylori infection is primarily acquired during childhood, causes chronic, active gastritis and peptic ulcer disease, and is associated with the development of gastric malignancies. However, only a small number of infected individuals ever develop the more severe sequelae of peptic ulcer disease and gastric cancers. Therefore, the identification of bacterial and host factors that play a role in determining the outcomes and pathophysiology of infection is a major focus of current research. Recent advances in the understanding of disease pathogenesis are critically considered, with particular reference to the pediatric population.

Helicobacter pylori-epithelial cell interactions: from adhesion to apoptosis

Studies suggest that host cell signal transduction cascades are manipulated during infection with microbes, including the gastric pathogen Helicobacter pylori. Several putative adhesins have been proposed to mediate the attachment of H pylori to gastric epithelial cells. Following bacterial binding, a series of signalling pathways are activated in the infected gastric epithelial cell. These signals include both cytoplasmic (such as vacuolization, tyrosine phosphorylation and elevation of cytosolic calcium) and nuclear (proliferation, apoptosis and chemokine transcription) events. Research aimed at elucidating the interactions that occur between the host cell and the bacterium during infection should improve the limited knowledge of disease pathogenesis.

Surface hydrophobicity is increased in the ileum and proximal colon of cystic fibrosis mice

Patients with cystic fibrosis (CF) have abnormal concentrations and composition of electrolytes and macromolecules in gastrointestinal secretions. Such alterations could change intestinal surface properties, such as surface hydrophobicity, and may influence the adhesion of macromolecules, bacteria, or microbial toxins to the intestinal surface. The objective of this study was to compare the surface hydrophobicity of the gastrointestinal tract in wild type and CF mice. We used axisymmetric drop shape analysis-contact diameter to determine surface hydrophobicity by measuring contact angles of sessile water droplets placed onto epithelial surfaces. In wild type mice, there were no differences in contact angles between the duodenum, upper jejunum, lower jejunum, and ileum. The contact angle of the gastric mucosa was lower than the rest of the gastrointestinal tract. Contact angles of the proximal colon and distal colon were both higher than that of the gastric mucosa and those of the small intestinal sections. In CF mice, contact angles along the gastrointestinal tract followed the same pattern as in wild type mice. However, contact angles in the ileum and proximal colon of CF mice were greater than those from wild type mice. This study of the murine intestine showed regional differences in surface hydrophobicity comparable to those observed in other mammalian species. In addition, we showed that the ileum and proximal colon of CF mice were more hydrophobic than the corresponding segments in wild type mice. These observations are of potential clinical relevance because patients with CF exhibit clinical manifestations of gastrointestinal disease primarily in the ileum and proximal colon.

Helicobacter pylori induces gastric epithelial cell apoptosis in association with increased Fas receptor expression

The mechanisms involved in mediating the enhanced gastric epithelial cell apoptosis observed during infection with Helicobacter pylori in vivo are unknown. To determine whether H. pylori directly induces apoptosis of gastric epithelial cells in vitro and to define the role of the Fas-Fas ligand signal transduction cascade, human gastric epithelial cells were infected with H. pylori for up to 72 h under microaerophilic conditions. As assessed by both transmission electron microscopy and fluorescence microscopy, incubation with a cagA-positive, cagE-positive, VacA-positive clinical H. pylori isolate stimulated an increase in apoptosis compared to the apoptosis of untreated AGS cells (16.0% +/- 2.8% versus 5.9% +/- 1. 4%, P < 0.05) after 72 h. In contrast, apoptosis was not detected following infection with cagA-negative, cagE-negative, VacA-negative clinical isolates or a Campylobacter jejuni strain. In addition to stimulating apoptosis, infection with H. pylori enhanced Fas receptor expression in AGS cells to a degree comparable to that of treatment with a positive control, gamma interferon (12.5 ng/ml) (148% +/- 24% and 167% +/- 24% of control, respectively). The enhanced Fas receptor expression was associated with increased sensitivity to Fas-mediated cell death. Ligation of the Fas receptor with an agonistic monoclonal antibody resulted in an increase in apoptosis compared to the apoptosis of cells infected with the bacterium alone (38.5% +/- 7.1% versus 16.0% +/- 2.8%, P < 0.05). Incubation with neutralizing anti-Fas antibody did not prevent apoptosis of H. pylori-infected cells. Taken together, these findings demonstrate that the gastric pathogen H. pylori stimulates apoptosis of gastric epithelial cells in vitro in association with the enhanced expression of the Fas receptor. These data indicate a role for Fas-mediated signaling in the programmed cell death that occurs in response to H. pylori infection.

Modulation of host cell membrane fluidity: a novel mechanism for preventing bacterial adhesion

Adhesion of bacterial enteropathogens to host mucosal surfaces is a critical primary step in the pathogenesis of diarrheal disease. We investigated the effects of altering the physical properties of eukaryotic cells on bacterial adhesion with the use of a series of three structurally dissimilar membrane fluidizers and several Escherichia coli as test strains. Lipid fluidity of the cell plasma membrane was measured by steady-state fluorescence anisotropy employing the probe 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3, 5-hexatriene. There was a dose-dependent and reversible inhibition of bacterial adhesion with increasing membrane fluidity. Time course experiments indicated that increasing membrane fluidity during the early stages of bacterial adhesion was essential for inhibition of attachment. None of the fluidizers affected the viability of either eukaryotic or prokaryotic cells. These findings demonstrate, for the first time, that changes in plasma membrane physical properties of epithelial cells can prevent microbial adhesion. This also suggests that altering the membrane properties of host cells could form a basis for novel strategies to prevent bacterial adhesion during infection in vivo.

Improved effects of novel glucocorticosteroids on immune-induced epithelial pathophysiology

Glucocorticosteroids are a mainstay therapy in inflammatory bowel disease and other chronic inflammatory conditions. However, severe systemic side effects are associated with their long-term use. The new generation of glucocorticosteroids have a high degree of topical activity with reduced systemic effects due to rapid metabolism. We previously described an in vitro model of inflammation in which monolayers of the human T84 colonic epithelial cell line displayed altered ion secretion and increased permeability after coculture with endotoxin-activated monocytes/macrophages (MPhi). Here, we tested the effects of budesonide and two novel analogs, D5519 and S1316, on MPhi-induced epithelial changes. Filter-grown T84 monolayers were cocultured with activated MPhi and single daily doses of drug were added to the luminal (physiological) side of the monolayer. Basal and stimulated epithelial ion transport [baseline short-circuit current (Isc) and DeltaIsc to forskolin, respectively] and barrier (transepithelial resistance) parameters were measured 48 h later in Ussing chambers. D5519, S1316, and budesonide (10(-7) to 10(-9) M) dose dependently inhibited the MPhi-induced epithelial abnormalities, restoring normal resistance, decreasing the elevated baseline Isc, and improving the reduced Isc response to forskolin. Of the drugs tested, D5519 was consistently the most potent and effective in inhibiting the MPhi-induced epithelial irregularities. Coupled with a further improvement in their rate of hepatic inactivation, our findings indicate that the novel steroids, particularly D5519, will be a valuable addition to current treatment strategies for inflammatory bowel disease and other chronic inflammatory conditions.

Development of a quality-of-life index for pediatric inflammatory bowel disease: dealing with differences related to age and IBD type

BACKGROUND

A child- and adolescent-generated IBD quality-of-life index was designed to be descriptive (to be used to assess the overall impact of IBD on individual patients), and evaluative (to be used as an outcome measure in clinical trials).

METHODS

Item-generation and item-reduction interviews with 82 patients with IBD aged 8 to 17 years (61 with Crohn's disease, 21 with ulcerative colitis; 36 girls, 45 boys) generated a list of ways in which their lives were affected by IBD. These issues were incorporated into an item-reduction questionnaire, which was administered to 117 patients (87 Crohn's disease, 30 ulcerative colitis). Patients indicated on a visual analog scale how important an item was to them and how often it bothered them. Mean and median importance-plus-frequency scores for each issue were calculated for the entire group and among patients in subgroups according to age and IBD type.

RESULTS

Ulcerative colitis and Crohn's disease affect the lives of children and adolescents differently. Bowel symptoms are more troubling and disabling to patients with ulcerative colitis, whereas systemic symptoms and body image concerns are greater for patients with Crohn's disease. The impact of Crohn's disease on ability to function in school and leisure activities is greater. Worries about future health problems and about the effects of IBD on the family are shared. Crohn's disease and ulcerative colitis trigger emotional responses of unfairness and frustration, but anger and embarrassment are more prevalent in ulcerative colitis. Disparities between age groups are fewer and less marked than those between types of IBD.

CONCLUSION

In selection of items to be retained in a pediatric IBD quality-of-life measure, the variation in concerns with disease type must be considered. A single index to assess IBD-related quality of life must include items of major importance to one subgroup of patients, even if not important to all. Alternately, a core of common concerns could be supplemented by disease-specific modules, thereby increasing the content validity of the tool for all patients.

Understanding disease outcome following acquisition of Helicobacter pylori infection during childhood

Helicobacter pylori causes chronic active (type B) gastritis in the overwhelming majority of infected individuals. The relative contribution of virulence factors in the bacterium and host responses to the microbial infection in determining which subjects will go on to develop complications - such as peptic ulceration, gastric cancers and gastric lymphomas - is the subject of current investigative activities.

Assessing activity of pediatric Crohn's disease: which index to use?

BACKGROUND & AIMS

The Pediatric Crohn's Disease Activity Index (PCDAI) is a multi-item measure that, in contrast to the adult-derived CDAI, includes linear growth and places less emphasis on subjectively reported symptoms but more on laboratory parameters of intestinal inflammation. This study compared the feasibility, validity, and responsiveness of PCDAI vs. CDAI in the assessment of Crohn's disease activity among pediatric patients.

METHODS

Eighty-one children and adolescents with Crohn's disease were studied. A gastroenterologist provided a categorical global assessment of disease activity as quiescent, mild, moderate, or severe after interview and physical examination. CDAI and PCDAI scores were calculated by an independent appraiser.

RESULTS

Mean values within each category for CDAI and PCDAI differed significantly between strata. PCDAI values were quiescent, 6.8 +/- 6. 6; mild, 18.7 +/- 7.3; moderate, 38.5 +/- 12.9; and severe, 54.2 +/- 14.0. CDAI values were quiescent, 23.5 +/- 53.6; mild, 96.0 +/- 60. 7; moderate, 184.5 +/- 97.0; and severe, 284.4 +/- 85.8. Individual scores showed less overlap between strata for PCDAI than for CDAI. PCDAI showed better correlation with serum orosomucoid and platelet count, laboratory parameters of inflammation not included in either index.

CONCLUSIONS

Both PCDAI and CDAI reflect disease activity in pediatric Crohn's disease. PCDAI is better at discriminating between levels of disease activity.