A Novel Human Epithelial Enteroid Model of Necrotizing Enterocolitis.

Necrotizing enterocolitis (NEC) is a devastating disease of newborn infants. It is characterized by multiple pathophysiologic alterations in the human intestinal epithelium, leading to increased intestinal permeability, impaired restitution, and increased cell death. Although there are numerous animal models of NEC, response to injury and therapeutic interventions may be highly variable between species. Furthermore, it is ethically challenging to study disease pathophysiology or novel therapeutic agents directly in human subjects, especially children. Therefore, it is highly desirable to develop a novel model of NEC using human tissue. Enteroids are 3-dimensional organoids derived from intestinal epithelial cells. They are ideal for the study of complex physiologic interactions, cell signaling, and host-pathogen defense. In this manuscript we describe a protocol that cultures human enteroids after isolating intestinal stem cells from patients undergoing bowel resection. The crypt cells are cultured in media containing growth factors that encourage differentiation into the various cell types native of the human intestinal epithelium. These cells are grown in a synthetic, collagenous mix of proteins that serve as a scaffold, mimicking the extra-cellular basement membrane. As a result, enteroids develop apical-basolateral polarity. Co-administration of lipopolysaccharide (LPS) in media causes an inflammatory response in the enteroids, leading to histologic, genetic, and protein expression alterations similar to those seen in human NEC. An experimental model of NEC using human tissue may provide a more accurate platform for drug and treatment testing prior to human trials, as we strive to identify a cure for this disease.

Outcomes and associated ethical considerations of long-run pediatric ECMO at a single center institution.

PURPOSE: Survival of neonatal and pediatric patients undergoing extracorporeal membrane oxygenation (ECMO) ≥ 21 days has not been well described. We hypothesized that patients would have poor survival and increased long-term complications. METHODS: Retrospective, single center, review and case analysis. Tertiary-care university children's hospital including neonatal, pediatric and cardiac intensive care units. After institutional review board approval, the charts of all patients < 18 years of age undergoing ECMO for ≥ 21 continuous days were performed, and they were compared to comparative patients undergoing shorter runs. Overall survival, incidence of complications, and post-discharge recovery were recorded. RESULTS: Overall survival was 36% in patients undergoing ≥ 21 days of ECMO (N = 14). 5/8 patients with cardiopulmonary failure from acquired etiologies survived versus 0/6 patients with congenital anomalies. 1/5 survivors achieved complete recovery with no neurologic deficits. The remaining survivors suffer from multiple medical and neurodevelopmental morbidities. CONCLUSION: ECMO support for ≥ 21 days is associated with poor survival, particularly in neonates with congenital anomalies. Long-term outcomes for survivors ought to be carefully weighed and discussed with parents given the high incidence of neurologic morbidities in this population.

Utility of liver biopsy in the evaluation of pediatric total parenteral nutrition cholestasis.

BACKGROUND: Cholestasis is a serious complication of total parenteral nutrition (TPN) in neonates. Liver biopsies may be requested to assess the severity of cholestasis and fibrosis. We hypothesized that liver biopsy would not lead to changes in management or improved patient outcomes. METHODS: A single institution retrospective review of infants with TPN cholestasis from January 2008 to January 2016. OUTCOMES: length of stay, complications, change in management and mortality. Statistical analysis was performed using Fisher's exact test. RESULTS: Twenty-seven out of 95 patients with TPN cholestasis underwent liver biopsy. Liver biopsy was associated with increased utilization or ursodeoxycholic acid (p = 0.001). There were no differences in length of stay (LOS) or mortality. One patient had a complication following anesthesia for liver biopsy, there were no bleeding complications recorded. CONCLUSIONS: Liver biopsy in patients with TPN cholestasis was associated with an increase in utilization of ursodeoxycholic acid. The effects of this are not fully understood; however, liver biopsy was not associated with improved patient outcomes such as LOS or mortality.

The science and necessity of using animal models in the study of necrotizing enterocolitis.

Necrotizing enterocolitis (NEC) remains one of the highest causes of mortality and of acute and long-term morbidity in premature infants. Multiple factors are involved in the pathophysiology of NEC including the immaturity of the immune system and the complex changing composition of the intestinal microbiome. This is compounded by the fact that the premature infant should ideally still be a developing fetus and has an immature intestinal tract. Because these complexities are beyond the scope of studies in single-cell cultures, animal models are absolutely essential to understand the mechanisms involved in the pathophysiology of NEC and the effects of inflammation on the immature intestinal tract. To this end, investigators have utilized many different species (e.g., rats, mice, rabbits, quails, piglets, and non-human primates) and conditions to develop models of NEC. Each animal has distinct advantages and drawbacks related to its preterm viability, body size, genetic variability, and cost. The choice of animal model is strongly influenced by the scientific question being addressed. While no model perfectly mimics human NEC, each has greatly improved our understanding of disease. Examples of recent discoveries in NEC pathogenesis and prevention underscore the importance of continued animal research in NEC.

Effect of preadmission bowel preparation on outcomes of elective colorectal procedures in young children.

BACKGROUND: The utility of mechanical bowel preparation (MBP) to minimize infectious complications in elective colorectal surgery is contentious. Though data is scarce in children, adult studies suggest a benefit to MBP when administered with oral antibiotics (OAB). METHODS: After IRB approval, the Pediatric Health Information System (PHIS) was queried for young children undergoing elective colon surgery from 2011 to 2014. Patients were divided into: no bowel preparation (Group 1), MBP (Group 2), and MBP plus OAB (Group 3). Statistical significance was determined using univariate and multivariate analysis with GEE models accounting for clustering by hospital. RESULTS: One thousand five hundred eighty-one patients met study criteria: 63.7% in Group 1, 27.1% in Group 2, and 9.2% in Group 3. Surgical complication rate was higher in Group 1 (23.3%) compared to Groups 2 and 3 (14.2% and 15.5%; P<0.001). However, median length of stay was shorter in Group 1 (4, IQR 4days) compared to Group 2 (5, IQR 3) and Group 3 (6, IQR 3) (P<0.001). 30-day readmission rates were similar. In multivariate analysis compared to patients in Group 1, the odds of surgical complications were 0.72 (95% CI 0.40-1.29, P=0.28) with MBP alone (Group 2), 1.79 (95% CI 1.28-2.52, P=0.0008) with MBP+OAB (Group 3), and 1.13 (95% CI 0.81-1.58, P=0.46) for the aggregate Group 2 plus 3. CONCLUSION: Utilization of bowel preparation in children is variable across children's hospitals nationally, and the benefit is unclear. Given the discrepancy with adult literature, a three-armed pediatric-specific randomized controlled trial is warranted. LEVEL OF EVIDENCE: Level III treatment study - retrospective comparative study.