[Show abstract][Hide abstract] ABSTRACT: Necrotizing enterocolitis (NEC) affects up to 10% of premature infants, has a mortality of 30%, and can leave surviving patients with significant morbidity. Neuregulin-4 (NRG4) is an ErbB4-specific ligand that promotes epithelial cell survival. Thus, this pathway could be protective in diseases such as NEC, in which epithelial cell death is a major pathologic feature. We sought to determine whether NRG4-ErbB4 signaling is protective in experimental NEC. NRG4 was used i) in the newborn rat formula feeding/hypoxia model; ii) in a recently developed model in which 14- to 16-day-old mice are injected with dithizone to induce Paneth cell loss, followed by Klebsiella pneumoniae infection to induce intestinal injury; and iii) in bacterially infected IEC-6 cells in vitro. NRG4 reduced NEC incidence and severity in the formula feed/hypoxia rat model. It also reduced Paneth cell ablation–induced NEC and prevented dithizone-induced Paneth cell loss in mice. In vitro, cultured ErbB4−/− ileal epithelial enteroids had reduced Paneth cell markers and were highly sensitive to inflammatory cytokines. Furthermore, NRG4 blocked, through a Src-dependent pathway, Cronobacter muytjensii–induced IEC-6 cell apoptosis. The potential clinical relevance of these findings was demonstrated by the observation that NRG4 and its receptor ErbB4 are present in human breast milk and developing human intestine, respectively. Thus, NRG4-ErbB4 signaling may be a novel pathway for therapeutic intervention or prevention in NEC.
American Journal Of Pathology 10/2014; · 4.60 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Prehospital traumatic cardiopulmonary arrest is associated with dismal prognosis, and patients rarely survive to hospital discharge. Recently established guidelines do not apply to the pediatric population because of paucity of data. The study objective was to determine the survival of pediatric patients presenting in the field with no signs of life after blunt trauma.
The Journal of Trauma and Acute Care Surgery 09/2014; 77(3):422-426. · 1.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Purpose
The effect of timing of onset of necrotizing enterocolitis (NEC) on outcomes has not been determined for the full-term infant. In this study we aimed to characterize the full-term NEC population and to evaluate onset of NEC.
We performed a two-center retrospective review of all full-term infants (≥ 37 weeks) with a diagnosis of NEC between 1990 and 2012. Patients were identified by ICD-9 and age. Early onset for NEC was ≤ 7 days and late onset after 7 days of life. Demographics, comorbidities, maternal factors, clinical factors, surgical intervention, complications, and mortality were evaluated. Wilcoxon’s test was performed on continuous variables and Fisher’s exact test on categorical data. A p-value < 0.05 was considered significant. Univariate outcomes with a p-value < 0.1 were selected for multivariable analysis.
Thirty-nine patients (24 boys, 15 girls) with median EGA of 39 weeks were identified. Overall mortality was 18%. Univariate predictors of mortality included congenital heart disease and placement of an umbilical artery (UA) catheter. Multivariate analysis revealed late onset of NEC to be an independent predictor of mortality (OR 90.8, 95% CI 2.6-3121).
Full-term infants who develop NEC after 7 days of life, have congenital heart disease, and/or need UA catheterization have increased mortality.
Journal of Pediatric Surgery 06/2014; · 1.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Pyloric atresia with epidermolysis bullosa (EB) dystrophica is a rare entity that may not be immediately recognized. We describe the fourth confirmed case of pyloric atresia associated with the dystrophic subtype of EB diagnosed by standard pathologic measures, and discuss the clinical disease features and recent advances in the pathophysiology.
Pediatric Surgery International 04/2014; · 1.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Purpose: The intestinal microbiota is altered in numerous pathologies including necrotizing enterocolitis (NEC), although how changes in the bacterial milieu lead to intestinal damage is unknown. Bacteria are responsible for modification of bile acids by first deconjugation followed by dehydroxylation, converting conjugated primary bile acids into more hydrophobic deconjugated secondary acids. Increased levels of secondary bile acids are found in the intestinal lumen in experimental NEC and have been implicated in intestinal epithelial cell damage. Epidermal growth factor (EGF) is known to play a key role in enterocyte migration and proliferation. We hypothesized that secondary bile acids may play a role in intestinal damage by modulating epithelial cell migration via the EGF receptor (EGFR).
Methods: After 24 hour treatment in serum-starved conditions, IEC-6 cell monolayers were subjected to a modified scratch wound restitution assay in the presence of bile acids, EGF, the EGFR inhibitor AG1478, or a combination. Pictures were taken at zero and six hours and compared for wound closure. Bile acid dosing was based on viability studies using a MTS-based assay. The dose used in the migration studies was the highest nontoxic dose for each bile acid.
Results: At the doses tested, neither glycine- nor taurine-conjugated bile acids altered baseline epithelial cell migration. Unconjugated primary bile acids cholic and chenodeoxycholic also did not alter cell migration versus control. In contrast, unconjugated secondary bile acids deoxycholic (DCA) and lithocholic (LCA) decreased baseline migration 14 and 45%, respectively. However, when cells were exposed to DCA and EGF together, cell migration was stimulated by 25%, similar to the 40% increase in migration seen with EGF treatment alone. Interestingly, EGF only partially reversed the decrease in cell migration seen with LCA alone. Ursodeoxycholic acid (UDCA), a tertiary bile acid, was the only bile acid tested that stimulated cell migration (20% above control). UDCA plus EGFR inhibitor resulted in a decrease in cell migration similar to levels seen with EGFR inhibitor alone (73 versus 71% respectively). When added in combination, UDCA reversed DCA-induced inhibition of cell migration, although migration only returned to control levels without exceeding them. The LCA-induced decrease in migration, however, was not altered by the addition of UDCA.
Conclusion: These data demonstrate that UDCA promotes epithelial cell migration via an EGFR-dependent mechanism. Secondary bile acids DCA and LCA inhibit intestinal epithelial restitution possibly through a mechanism involving EGFR inhibition. Further, UDCA reverses DCA-induced inhibition of migration. These mechanisms provide insight into how secondary bile acids may play a role in the pathogenesis of diseases such as NEC and how UDCA administration may modulate these effects via the EGFR pathway.
2013 American Academy of Pediatrics National Conference and Exhibition; 10/2013
[Show abstract][Hide abstract] ABSTRACT: The intestinal barrier becomes compromised during systemic inflammation, leading to the entry of luminal bacteria into the host and gut origin sepsis. Pathogenesis and treatment of inflammatory gut barrier failure is an important problem in critical care. In this study, we examined the role of cyclooxygenase-2 (COX-2), a key enzyme in the production of inflammatory prostanoids, in gut barrier failure during experimental peritonitis in mice. I.p. injection of LPS or cecal ligation and puncture (CLP) increased the levels of COX-2 and its product prostaglandin E2 (PGE2) in the ileal mucosa, caused pathologic sloughing of the intestinal epithelium, increased passage of FITC-dextran and bacterial translocation across the barrier, and increased internalization of the tight junction (TJ)-associated proteins junction-associated molecule-A and zonula occludens-1. Luminal instillation of PGE2 in an isolated ileal loop increased transepithelial passage of FITC-dextran. Low doses (0.5-1 mg/kg), but not a higher dose (5 mg/kg) of the specific COX-2 inhibitor Celecoxib partially ameliorated the inflammatory gut barrier failure. These results demonstrate that high levels of COX-2-derived PGE2 seen in the mucosa during peritonitis contribute to gut barrier failure, presumably by compromising TJs. Low doses of specific COX-2 inhibitors may blunt this effect while preserving the homeostatic function of COX-2-derived prostanoids. Low doses of COX-2 inhibitors may find use as an adjunct barrier-protecting therapy in critically ill patients.Laboratory Investigation advance online publication, 14 October 2013; doi:10.1038/labinvest.2013.119.
[Show abstract][Hide abstract] ABSTRACT: Hirschsprung's-associated enterocolitis (HAEC) continues to be a significant source of morbidity for patients with Hirschsprung's disease (HD). New clinical and histologic classification systems for HAEC will improve consistency between reports and increase the ability to compare outcomes. A complete understanding of disease pathogenesis is lacking, but evidence suggests that the intestinal microbiota may play a role in the development of HD and HAEC. The benefits of adjunctive therapies, such as anal dilations and botulinum toxin to reduce the incidence of HAEC following corrective endorectal pull-through, remain controversial. Finally, new clinical data have identified an association between HAEC and inflammatory bowel disease and will likely lead to further genetic studies to elucidate the connection between these two disease processes.
Current Gastroenterology Reports 08/2013; 15(8):340.
[Show abstract][Hide abstract] ABSTRACT: Disasters occur randomly and can severely tax the health care delivery system of affected and surrounding regions. A significant proportion of disaster survivors are children, who have unique medical, psychosocial, and logistical needs after a mass casualty event. Children are often transported to specialty centers after disasters for a higher level of pediatric care, but this can also lead to separation of these survivors from their families. In a recent theoretical article, we showed that the availability of a pediatric trauma center after a mass casualty event would decrease the time needed to definitively treat the pediatric survivor cohort and decrease pediatric mortality. However, we also found that if the pediatric center was too slow in admitting and discharging patients, these benefits were at risk of being lost as children became "trapped" in the slow center. We hypothesized that this effect could result in further increased mortality and greater costs.
Here, we expand on these ideas to test this hypothesis via mathematical simulation. We examine how a delay in discharge of part of the pediatric cohort is predicted to affect mortality and the cost of inpatient care in the setting of our model.
We find that mortality would increase slightly (from 14.2%-16.1%), and the cost of inpatient care increases dramatically (by a factor of 21) if children are discharged at rates consistent with reported delays to reunification after a disaster from the literature.
Our results argue for the ongoing improvement of identification technology and logistics for rapid reunification of pediatric survivors with their families after mass casualty events.
Journal of Surgical Research 06/2013; · 2.12 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Development of necrotizing enterocolitis (NEC) requires a susceptible host, typically a premature infant or an infant with congenital heart disease, enteral feedings and bacterial colonization. Although there is little doubt that microbes are critically involved in the pathogenesis of NEC, the identity of specific causative pathogens remains elusive. Unlike established normal adult gut microbiota, which is quite complex, uniform, and stable, early postnatal bacterial populations are simple, diverse, and fluid. These properties complicate studies aimed at elucidating characteristics of the gut microbiome that may play a role in the pathogenesis of NEC. A broad variety of bacterial, viral, and fungal species have been implicated in both clinical and experimental NEC. Frequently, however, the same species have also been found in physiologically matched healthy individuals. Clustered outbreaks of NEC, in which the same strain of a suspected pathogen is detected in several patients suggest, but do not prove, a causative relationship between the specific pathogen and the disease. Studies in Cronobacter sakazakii, the best characterized NEC pathogen, have demonstrated that virulence is not a property of a bacterial species as a whole, but rather a characteristic of certain strains, which may explain why the same species can be pathogenic or non-pathogenic. The fact that a given microbe may be innocuous in a full-term, yet pathogenic in a pre-term infant has led to the idea of opportunistic pathogens in NEC. Progress in understanding the infectious nature of NEC may require identifying specific pathogenic strains and unambiguously establishing their virulence in animal models.
Seminars in Pediatric Surgery 05/2013; 22(2):69-75. · 1.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: PURPOSE: Heterotaxy syndrome is associated with intestinal abnormalities. We sought to define the gastrointestinal anatomy and determine both the risk of volvulus and benefit of screening upper gastrointestinal fluoroscopy (UGI) in these patients. METHODS: Medical records from 2003 until 2011 at Children's Hospital Los Angeles were reviewed in patients with heterotaxy for cardiovascular diagnosis, gastrointestinal symptoms, imaging and surgical arrangement of viscera, perioperative morbidities, and overall mortality. RESULTS: 224 patients were identified. Fifteen had polysplenia, 41 had asplenia, 50 had normal splenic morphology, 13 had inversus, and 104 were uncharacterized. UGI was performed in 4 patients for suspected volvulus and 20 for obstructive symptoms. Sixty-two had "screening" UGIs. Of 138 asymptomatic patients without imaging, none developed volvulus during the study period. In 30 patients with duodenojejunal malposition (DJM) who underwent surgery, none had malrotation or narrow mesentery. Eleven developed complications, with 8 requiring reoperation for obstruction. Of 8 patients with malrotation, 7 received a Ladd's procedure, and 2 had volvulus with viable bowel. One patient required reoperation and resection for obstruction. CONCLUSION: While rotational abnormalities are common in heterotaxy, risk of volvulus is low. Following operation, the risk of bowel obstruction and of need for reoperation is higher. We advocate avoiding operation in the asymptomatic patient.
Journal of Pediatric Surgery 01/2013; 48(1):164-169. · 1.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The signaling pathways that are essential for gastric organogenesis have been studied in some detail; however, those that regulate the maintenance of the gastric epithelium during adult homeostasis remain unclear. In this study, we investigated the role of Fibroblast growth factor 10 (FGF10) and its main receptor, Fibroblast growth factor receptor 2b (FGFR2b), in adult glandular stomach homeostasis. We first showed that mouse adult glandular stomach expressed Fgf10, its receptors, Fgfr1b and Fgfr2b, and most of the other FGFR2b ligands (Fgf1, Fgf7, Fgf22) except for Fgf3 and Fgf20. Fgf10 expression was mesenchymal whereas FGFR1 and FGFR2 expression were mostly epithelial. Studying double transgenic mice that allow inducible overexpression of Fgf10 in adult mice, we showed that Fgf10 overexpression in normal adult glandular stomach increased epithelial proliferation, drove mucous neck cell differentiation, and reduced parietal and chief cell differentiation. Although a similar phenotype can be associated with the development of metaplasia, we found that Fgf10 overexpression for a short duration does not cause metaplasia. Finally, investigating double transgenic mice that allow the expression of a soluble form of Fgfr2b, FGF10's main receptor, which acts as a dominant negative, we found no significant changes in gastric epithelial proliferation or differentiation in the mutants. Our work provides evidence, for the first time, that the FGF10-FGFR2b signaling pathway is not required for epithelial proliferation and differentiation during adult glandular stomach homeostasis.
PLoS ONE 11/2012; 7(11):e49127. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Purpose: Patients with a diagnosis of heterotaxy engender concern for the clinicians who care for them because they seem to “do worse.” It is increasingly recognized that heterotaxy includes a wide spectrum of abnormalities in the arrangement of thoracoabdominal organs beyond simple isomerism that makes it hard to define as a syndrome. We sought to identify groups of patients who should be suspected as having heterotaxy, define their workup, and determine the morbidities and mortality risk for these patients. We hypothesize that heterotaxy should be viewed as a complex and not a syndrome.
Methods: A search for of MEDLINE, the National Library of Medicine Medical Subject Headings, and International Pediatric and Congenital Cardiac Code was performed for heterotaxy, disorders of organ situs and abdominal rotation, and disorders of ciliary dysfunction for both hepatobiliary and pulmonary diseases. After IRB approval, medical records between July 2003 and July 2011 at our institute were queried for patients with these diagnoses. Data collected included demographics, cardiovascular and noncardiac diagnoses, imaging and surgical/autopsy appearance of thoracoabdominal organs, and overall mortality.
Results: 224 patients presented with congenital heart disease (CHD) and were confirmed as having heterotaxy. 19 patients presenting with CHD without heterotaxy were found to have malrotation. 61 patients were identified with malrotation without mechanical cause or chromosomal abnormality. 78 patients presented with biliary atresia. 11 patients were identified as having a primary ciliary dyskinesia. Associations between presentation and organ findings are shown in the table. Overall mortality was 83.7%.
Conclusion: Although the classic description of heterotaxy syndrome relies upon the presence of isomerism, it is now clear that significant deviation from the usual visceral asymmetry can occur without bilateral sidedness. Our data supports a non-random relationship between solid and hollow organ situs and CHD. Multiple correlations are the hallmark of a disease complex: we believe that heterotaxy should be considered a complex including a situs abnormality and a dysfunctional organ rather than a syndrome of bilateral sidedness. We therefore we recommend these patients undergo a careful history, physical examination, chest x-ray, peripheral blood smear, echocardiogram, and abdominal ultrasound. We also indicate potential non-cardiac morbidities in this group of patients. Further study will clarify the requirements for inclusion into heterotaxy complex.
Classic Heterotaxy Cardiac Lesion
Splenic Situs Abnormality
CHD then Malrotation
2012 American Academy of Pediatrics National Conference and Exhibition; 10/2012
[Show abstract][Hide abstract] ABSTRACT: Purpose: Psychosocial, sociocultural, and socioeconomic variables play a significant role in the outcomes of surgical disease, and while family structure has been evaluated in the social sciences, its clinical implications are not well known. Single ventricle (SV) congenital heart disease requires a series of palliative surgical procedures and multiple hospital admissions. Our goal was to evaluate the impact of family and socioeconomic contributions to treatment progression and survival in patients with single ventricle disease. We hypothesized that SV infants/children with single or separated, unemployed, and uninsured caretakers with a primary language other than English had higher mortality between surgical palliative stages, compared to infants/children with more than one caretaker who is employed, has health insurance, and speaks English.
Methods: After IRB approval, all medical records between July 2003 and July 2010 at a single, tertiary care, university affiliated children’s hospital were reviewed for patients with a diagnosis of single ventricle. Social work notes were used to identify family structure, parental employment, insurance, and primary language. Outcomes included survival to each stage of repair (Stage I, Stage II – Bidirectional Glenn, and Stage III – Fontan completion) and overall survival. Data were analyzed using Chi-square analysis and multivariate logistic regression.
Results: Of 421 patients with SV disease, 99% had parents as guardians, (86% together, 5% separated, 8% single parent). Patients with separated parents had decreased survival between Stage I and Glenn (p=0.014), as well as between Glenn and Fontan (p<0.0001). In fact, separated parents led to a three-fold increase in mortality over single parents and couples. Unemployment of both parents also led to decreased survival between Glenn and Fontan (p=0.002). Additional adults, usually grandparents, were living in 22.8% of households. Survival was similar after Stage I and Glenn, but patients with additional adults had worse survival after Fontan (p=0.005). In general, patients with English as their primary language had better outcomes than secondary and non-English speakers, especially in survival to Fontan (p=0.058). Neither number of siblings nor type of insurance had an effect on survival at any stage.
Conclusion: The ongoing care of an infant with single ventricle disease is demanding. Families with additional challenges such as multiple households, multiple caretakers, and language barriers may affect the child’s chance of long-term survival. This effect is most noticeable between Glenn and Fontan, which is generally accepted as the safest periods from a physiologic standpoint. High-risk families such as those with separated parents, additional family members at home, or those who speak a primary language other than English may benefit from additional resources to improve patient survival and treatment progression. Family structure and socioeconomics must be taken into account to improve long-term outcomes in these fragile patients.
2012 American Academy of Pediatrics National Conference and Exhibition; 10/2012
[Show abstract][Hide abstract] ABSTRACT: Recent events including the 2001 terrorist attacks on New York; Hurricane Katrina; the 2010 Haitian and Chilean earthquakes; and the 2011 earthquake, tsunami, and nuclear disaster in Japan have reminded disaster planners and responders of the tremendous scale of mass casualty disasters and their resulting human devastation. Although adult disaster medicine is a well-developed field with roots in wartime medicine, we are increasingly recognizing that children may comprise up to 50% of disaster victims, and response mechanisms are often designed without adequate preparation for the number of pediatric victims that can result. In this short educational review, we explore the differences between the pediatric and adult disaster and trauma populations, the requirements for designation of a site as a pediatric trauma center (PTC), and the magnitude of the problem of pediatric disaster patients as described in the literature, specifically as it pertains to the availability and use of designated PTCs as opposed to trauma centers in general. We also review our own experience in planning and simulating pediatric mass casualty events and suggest strategies for preparedness when there is no PTC available. We aim to demonstrate from this brief survey that the availability of a designated PTC in the setting of a mass casualty disaster event is likely to significantly improve the outcome for the pediatric demographic of the affected population. We conclude that the relative scarcity of disaster data specific to children limits epidemiologic study of the pediatric disaster population and offer suggestions for strategies for future study of our hypothesis. LEVEL OF EVIDENCE: Systematic review, level III.
The journal of trauma and acute care surgery. 07/2012; 73(4):885-9.