Yaron Avitzur

Probiotics Reduce Bacterial Colonization and Gastric Inflammation in H. pylori-Infected Mice

Probiotics are characterized by their ability to interact with commensal microflora in the gastrointestinal tract to produce beneficial health effects. In vitro studies suggest that Lactobacillus species have the potential to suppress the growth of Helicobacter pylori. The goal of this study was to determine if pretreatment of mice with a commercial mixture of live probiotics (L. rhamnosus, strain R0011, and L. acidophilus, strain R0052) would suppress colonization of H. pylori, strain SS1. Thirty C57BL/6 female mice were divided into four groups: Group A was fed sterile water, group B received probiotics in sterile drinking water, group C was challenged orogastrically with H. pylori, and group D was pretreated with probiotics in drinking water prior to and following challenge with H. pylori. Rectal swabs, stomach homogenates, and luminal contents from ileum and colon were plated onto colistin nalidixic acid plates. Serial dilutions of stomach homogenates were plated onto H. pylori-sensitive agar plates and incubated under microaerophilic conditions. Tissue samples from the stomach were analyzed histologically to determine the degree of H. pylori colonization, mucosal inflammation, and epithelial cell apoptosis. Probiotics in drinking water did not affect the overall well-being of mice. Lactobacillus species were excreted in stools over the entire duration of treatment. Pretreatment with probiotics reduced the number of mice with H. pylori growth from stomach homgenates (100 to 50%; P = 0.02). The percentage of mice with moderate-severe H. pylori-induced inflammation in the gastric antrum was reduced with probiotic pretreatment (71 to 29%; P = 0.14). However, pretreatment with probiotics did not prevent H. pylori-induced apoptosis in the gastric mucosa. This preparation of probiotics provided a safe and novel approach for reducing H. pylori colonization and bacterial-induced inflammation of mice.

Amelioration of the Effects of Citrobacter rodentium Infection in Mice by Pretreatment with Probiotics

BACKGROUND Citrobacter rodentium is a naturally occurring murine pathogen that causes colonic epithelial-cell hyperplasia, disrupts the colonic mucosa, and elicits a predominantly T helper 1 cellular immune response; it thereby serves as a model for the study of mechanisms of disease induced by human attaching-effacing pathogens. We sought to determine whether pretreatment of mice with a mixture of Lactobacillus rhamnosus and L. acidophilus probiotics would attenuate C. rodentium-induced colonic disease in mice. METHODS Mice were administered sterile drinking water, probiotics (10(9) cfu/mL) in sterile drinking water, maltodextrin in sterile drinking water, orogastric C. rodentium (10(7) cfu in 0.1 mL), or maltodextrin in sterile drinking water for 1 week before C. rodentium infection, or they were pretreated with probiotics (10(9) cfu/mL) for 1 week before challenge with C. rodentium. RESULTS Mice that received viable probiotics remained healthy. C. rodentium infection elicited mucosal inflammation, epithelial-cell hyperplasia, apoptosis in the colon, and interferon (IFN)- gamma production by splenocytes. Pretreatment with probiotics decreased levels of all but IFN- gamma production. CONCLUSIONS Pretreatment with probiotics attenuates the effects of C. rodentium infection in mice. Understanding the mechanism of these beneficial effects will aid in determining the efficacy of probiotics in preventing infection with related attaching-effacing enteric pathogens in humans.

Ethanol lock therapy to reduce the incidence of catheter-related bloodstream infections in home parenteral nutrition patients with intestinal failure: preliminary experience☆

BACKGROUND Catheter-related bloodstream infections (CRBSI) cause morbidity and mortality in patients with intestinal failure dependent on parenteral nutrition. Ethanol lock of central venous catheters may decrease CRBSI, but limited pediatric data are available. METHODS Home parenteral nutrition patients with at least one previous CRBSI were initiated on a 70% ethanol lock protocol for a minimum of 4 hours. Infection rates (per 1000 catheter days) before and after initiation of ethanol locks were compared using a paired t test. RESULTS Ten patients (4 girls; median age, 44 months [range, 31-129 months]) began ethanol lock therapy after a total of 91 CRBSIs (37 gram-positive, 30 gram-negative, and 24 fungal) with a mean of 10.2 ± 6.2 per 1000 catheter days. Patients received ethanol lock for an average of 227 ± 64 days with only 3 CRBSI occurring (CRBSI rate of 0.9 ± 1.8 per 1000 catheter days [P = .005]). Central venous catheter replacements decreased from 5.6 per 1000 days to 0.3 per 1000 days posttherapy (P = .038). Ethanol lock was discontinued in 2 of 10 patients because of catheter thrombosis. CONCLUSION Preliminary results demonstrate a significant decrease in CRBSI with a 70% ethanol lock protocol. Catheter thrombosis may be a limitation that needs to be addressed. With such a dramatic therapeutic effect, a randomized trial is feasible and should be performed.

Mutations in tetratricopeptide repeat domain 7A result in a severe form of very early onset inflammatory bowel disease

BACKGROUND & AIMS Very early onset inflammatory bowel diseases (VEOIBD), including infant disorders, are a diverse group of diseases found in children younger than 6 years of age. They have been associated with several gene variants. Our aim was to identify the genes that cause VEOIBD. METHODS We performed whole exome sequencing of DNA from 1 infant with severe enterocolitis and her parents. Candidate gene mutations were validated in 40 pediatric patients and functional studies were carried out using intestinal samples and human intestinal cell lines. RESULTS We identified compound heterozygote mutations in the Tetratricopeptide repeat domain 7 (TTC7A) gene in an infant from non-consanguineous parents with severe exfoliative apoptotic enterocolitis; we also detected TTC7A mutations in 2 unrelated families, each with 2 affected siblings. TTC7A interacts with EFR3 homolog B to regulate phosphatidylinositol 4-kinase at the plasma membrane. Functional studies demonstrated that TTC7A is expressed in human enterocytes. The mutations we identified in TTC7A result in either mislocalization or reduced expression of TTC7A. Phosphatidylinositol 4-kinase was found to co-immunoprecipitate with TTC7A; the identified TTC7A mutations reduced this binding. Knockdown of TTC7A in human intestinal-like cell lines reduced their adhesion, increased apoptosis, and decreased production of phosphatidylinositol 4-phosphate. CONCLUSIONS In a genetic analysis, we identified loss of function mutations in TTC7A in 5 infants with VEOIBD. Functional studies demonstrated that the mutations cause defects in enterocytes and T cells that lead to severe apoptotic enterocolitis. Defects in the phosphatidylinositol 4-kinase-TTC7A-EFR3 homolog B pathway are involved in the pathogenesis of VEOIBD.

The impact of multi-disciplinary intestinal rehabilitation programs on the outcome of pediatric patients with intestinal failure: a systematic review and meta-analysis.

BACKGROUND Pediatric intestinal failure (IF) is a complex clinical problem requiring coordinated multi-disciplinary care. Our objective was to review the evidence for the benefit of intestinal rehabilitation programs (IRP) in pediatric IF patients. METHODS A systematic review was performed on Medline (1950-2012), Pubmed (1966-2012), and Embase (1980-2012) conference proceedings and trial registries. The terms short bowel syndrome, intestinal rehabilitation, intestinal failure, patient care teams, and multi-disciplinary teams were used. Fifteen independent studies were included. Three studies that were cohort studies, including a comparison group, were included in a meta-analysis. RESULTS Compared to historical controls (n=103), implementation of an IRP (n=130) resulted in a reduction in septic episodes (0.3 vs. 0.5 event/month; p=0.01) and an increase in overall patient survival (22% to 42%). Non-significant improvements were seen in weaning from PN (RR=1.05, 0.88-1.25, p=0.62), incidence of IFALD (RR=0.2, 0-17.25, p=0.48), and relative risk of liver transplantation (3.99, 0.75-21.3, p=0.11). Other outcomes reported included a reduction in calories from parenteral nutrition (100% to 32%-56%), earlier surgical/transplant evaluation, and improved coordination of patient care. CONCLUSION For pediatric IF patients, IRPs are associated with reduced morbidity and mortality. Standardized clinical practice guidelines are necessary to provide uniform patient care and outcome assessment.

Sirolimus for pediatric liver transplant recipients with post‐transplant lymphoproliferative disease and hepatoblastoma

Abstract:  Sirolimus is a promising immune suppressive agent, with the potential to reduce calcineurin inhibitor associated nephrotoxicity, halt progression of chronic rejection and prevent tumor proliferation. The aim of this study was to review the experience using sirolimus in pediatric liver transplant recipients at a single center. Database and medical charts of all pediatric liver transplant recipients receiving sirolimus at the Hospital for Sick Children in Toronto were reviewed. Eight patients received sirolimus between October, 2000 and September, 2002. Indications for using sirolimus were post‐transplant lymphoproliferative disease (PTLD) (n = 6) and hepatoblastoma (n = 2). Two patients with PTLD concurrently had renal impairment and chronic rejection. Sirolimus dosages ranged between 1.5 and 5 mg once daily. Median duration of follow‐up was 17 months. Persistently elevated liver transaminase levels in the two children with chronic rejection decreased during sirolimus therapy. Recurrence of PTLD occurred in one patient. Two patients were diagnosed with acute cellular rejection after transition to maintenance sirolimus monotherapy. Resolution of adverse effects including mouth sores (n = 3), leg swelling (n =  2) and hyperlipidemia (n = 3) occurred either spontaneously or with dose reduction. Sirolimus was discontinued in four patients because of persisting bone marrow suppression, interstitial pneumonitis, life‐threatening sepsis and refractory diarrhea. Children with PTLD or hepatoblastoma may benefit from immune suppression with sirolimus after liver transplantation. Further multi‐center, prospective, randomized controlled trials will be instrumental to further the knowledge of long‐term efficacy, safety and tolerability of sirolimus for selected children following liver transplantation.

Health status ten years after pediatric liver transplantation--looking beyond the graft.

Background. Little is known about long-term health after pediatric orthotopic liver transplantation (OLT). This study aimed to characterize the health status of recipients 10 years after OLT, with an emphasis on transplant-related morbidity and quality of life. Methods. We performed a retrospective database review of 32 children who underwent OLT before October 1992 at one center and were alive after 10 years. Outcome measures were assessed 10 years after OLT. Cantril’s self-anchoring scale was used for global quality of life assessment. Results. Synthetic liver function at 10 years was preserved in all patients. The annual rate of episodes of acute rejection dropped markedly after the first year (1.4 at year 1 to 0.19 rejections/patient/year at year 10). Histologically confirmed chronic rejection developed in eight (25%) patients. At 10 years, long-term complications included mild to severe chronic renal failure (77%), mild chronic anemia (59%), and hypertension (25%). Significant growth retardation (z-score < −2), hyperlipidemia, and diabetes were uncommon. Infection requiring hospitalization occurred in 81% of the patients, with varicella zoster virus as the most common pathogen. Epstein-Barr virus-related malignancies affected 22% of patients. Ten-year survivors perceived quality of life as very good. Self-reporting of drug nonadherence by seven (22%) adolescents may have contributed to development of late onset rejection in this subgroup. Conclusions. Children who are 10-year survivors of OLT have excellent graft function and, despite chronic extrahepatic morbidities, a self-reported high quality of life.

Intestine Transplantation in Children: Update 2010

This article reviews the current status of pediatric intestinal transplantation, focusing on referral and listing criteria, surgical techniques, patient management, monitoring, complications after transplant, and short- and long-term patient outcome. Intestine transplantation has become the standard of care for children who develop life-threatening complications associated with intestinal failure. The results of intestinal failure treatment have significantly improved in the last decade following the establishment of gut rehabilitation programs and advances in transplant immunosuppressive protocols, surgical techniques, and posttransplant monitoring. The 1-year patient survival is now 80% and more than 80% of the children who survive the transplant are weaned off parenteral nutrition. Early referral for pretransplant assessment and careful follow-up after transplant with prompt recognition and treatment of transplant-related complications are key factors contributing to superior patient outcomes and survival. The best results are being obtained at high-volume centers with survival rates of up to 75% at 5 years.

Resting energy expenditure in children with cyanotic and noncyanotic congenital heart disease before and after open heart surgery.

BACKGROUND Failure to thrive is a common problem in children with congenital heart disease (CHD). Resting energy expenditure (REE) in cyanotic and noncyanotic children with CHD before and after open heart surgery has hardly been investigated. METHODS Twenty-nine children younger than 3 years of age with CHD (14 cyanotic and 15 noncyanotic CHD) who were referred for open heart surgery were enrolled. Data on dietary intake, anthropometric measurements, and indirect calorimetry parameters were measured 24 hours before the surgery, (day -1), and on day 5 after surgery. The measured REE was compared with the Schofield and World Health Organization (WHO) REE prediction equations. RESULTS The mean +/- SD measured REE was similar in the cyanotic and noncyanotic children before and after surgery (before surgery: 57 +/- 13 and 58 +/- 9 kcal/kg per day, respectively; 5 days after surgery: 59 +/- 10 and 62 +/- 10 kcal/kg per day, respectively). Oxygen consumption (VO2) and carbon dioxide production (VCO2) did not change significantly before and after surgery and were similar in both groups. The measured REE for all children on day -1 and day 5 was similar to the calculated REE using the Schofield equation but was significantly different from the calculated REE using the WHO equation (p < .01). CONCLUSIONS Significant changes in REE, VCO2, and VO2 were not observed before and 5 days after open heart surgery in children with CHD. These parameters (REE, VCO2, and VO2) were also similar in children with cyanotic versus noncyanotic CHD. The Schofield equation is more accurate than the WHO equation in predicting energy needs of children with CHD, but measurement of REE is preferred over calculation of REE.

A Clinical Prediction Rule and Platelet Count Predict Esophageal Varices in Children

BACKGROUND & AIMS The validation of noninvasive tests to diagnose esophageal varices is a priority in children because repeated endoscopic evaluations are too invasive. We measured the ability of a previously developed noninvasive clinical prediction rule (CPR) to predict the presence of esophageal varices in children. METHODS We analyzed data from 108 children, younger than age 18, who received endoscopies at 8 centers, to assess portal hypertension from chronic liver disease or portal vein obstruction. Blood test and abdominal ultrasound scan results were obtained within 4 months of endoscopy. Grading of varices identified by endoscopy was confirmed by independent blinded review. Spleen size, based on data from the ultrasound scan, was expressed as a standard deviation score relative to normal values for age. RESULTS Of the children studied, 74 had esophageal varices (69%), including 35 with large varices (32%). The best noninvasive predictors of esophageal varices of any size were as follows: platelet:spleen size z-score ratio (area under the receiver operating characteristic curve [AUROC], 0.84; 95% confidence interval [CI] 0.75-0.93), CPR (AUROC, 0.80; 95% CI, 0.70-0.91), and platelet count (AUROC, 0.79; 95% CI, 0.69-0.90). The positive predictive values for the CPR and platelet count were 0.87 and 0.86, the negative predictive values were 0.64 and 0.63, the positive likelihood ratios were 3.06 and 2.76, and the negative likelihood ratios were 0.64 and 0.63, respectively. Based on positive and negative predictive values, the most accurate noninvasive tests were the CPR and platelet counts. CONCLUSIONS Noninvasive tests such as CPR and platelet count can assist in triaging children for endoscopy to identify esophageal varices.