Factors Affecting the Gut Microbiome in Pediatric Intestinal Failure.

BACKGROUND: There is little data on gut microbiome and various factors that lead to dysbiosis in pediatric intestinal failure (PIF). This study aimed to characterize gut microbiome in PIF and determine factors that may affect microbial composition in these patients. METHODS: This is a single-center, prospective cohort study of children with PIF followed at our intestinal rehabilitation program. Stool samples were collected longitudinally at regular intervals over a 1-year period. Medical records were reviewed, and demographic and clinical data were collected. Medication history including the use of acid blockers, scheduled prophylactic antibiotics, and bile acid sequestrants was obtained. Gut microbial diversity among patients was assessed and compared according to various host characteristics of interest. RESULTS: The final analysis included 74 specimens from 12 subjects. Scheduled prophylactic antibiotics, presence of central line associated bloodstream infection (CLABSI) at the time of specimen collection, use of acid blockers, and ≥50% calories delivered via parenteral nutrition (PN) was associated with reduced alpha diversity, whereas increasing age was associated with improved alpha diversity at various microbial levels ( P value <0.05). Beta diversity differed with age, presence of CLABSI, use of scheduled antibiotics, acid blockers, percent calories via PN, and presence of oral feeds at various microbial levels ( P value <0.05). Single taxon analysis identified several taxa at several microbial levels, which were significantly associated with various host characteristics. CONCLUSION: Gut microbial diversity in PIF subjects is influenced by various factors involved in the rehabilitation process including medications, percent calories received parenterally, CLABSI events, the degree of oral feeding, and age. Additional investigation performed across multiple centers is needed to further understand the impact of these findings on important clinical outcomes in PIF.

Initial Laparotomy Versus Peritoneal Drainage in Extremely Low Birthweight Infants With Surgical Necrotizing Enterocolitis or Isolated Intestinal Perforation: A Multicenter Randomized Clinical Trial.

OBJECTIVE: The aim of this study was to determine which initial surgical treatment results in the lowest rate of death or neurodevelopmental impairment (NDI) in premature infants with necrotizing enterocolitis (NEC) or isolated intestinal perforation (IP). SUMMARY BACKGROUND DATA: The impact of initial laparotomy versus peritoneal drainage for NEC or IP on the rate of death or NDI in extremely low birth weight infants is unknown. METHODS: We conducted the largest feasible randomized trial in 20 US centers, comparing initial laparotomy versus peritoneal drainage. The primary outcome was a composite of death or NDI at 18 to 22 months corrected age, analyzed using prespecified frequentist and Bayesian approaches. RESULTS: Of 992 eligible infants, 310 were randomized and 96% had primary outcome assessed. Death or NDI occurred in 69% of infants in the laparotomy group versus 70% with drainage [adjusted relative risk (aRR) 1.0; 95% confidence interval (CI): 0.87-1.14]. A preplanned analysis identified an interaction between preoperative diagnosis and treatment group (P = 0.03). With a preoperative diagnosis of NEC, death or NDI occurred in 69% after laparotomy versus 85% with drainage (aRR 0.81; 95% CI: 0.64-1.04). The Bayesian posterior probability that laparotomy was beneficial (risk difference <0) for a preoperative diagnosis of NEC was 97%. For preoperative diagnosis of IP, death or NDI occurred in 69% after laparotomy versus 63% with drainage (aRR, 1.11; 95% CI: 0.95-1.31); Bayesian probability of benefit with laparotomy = 18%. CONCLUSIONS: There was no overall difference in death or NDI rates at 18 to 22 months corrected age between initial laparotomy versus drainage. However, the preoperative diagnosis of NEC or IP modified the impact of initial treatment.

Scheduled Empiric Antibiotics May Alter the Gut Microbiome and Nutrition Outcomes in Pediatric Intestinal Failure.

BACKGROUND: In this study, we aim to determine the effect of scheduled antibiotics on gut microbiome in pediatric intestinal failure (IF) and to evaluate the effect of the gut microbiome on nutrition outcomes in IF. METHODS: Fecal samples were collected at regular intervals from pediatric patients with IF for gut microbiome comparison between 2 cohorts: (group 1) those on scheduled prophylactic antibiotics and (group 2) those who were not on scheduled antibiotics. Gut microbiome composition and diversity were compared among the 2 cohorts. The association among gut microbiome composition, diversity, and nutrition outcomes (mainly ability to decrease parenteral nutrition [PN] energy requirement and ability to attain positive growth) was also determined. RESULTS: The microbiome of patients with IF on scheduled antibiotics differed significantly from those not on scheduled antibiotics. Abundance of certain Gram-negative and pathogenic bacteria (Pseudomonas, Prevotella, and Sutterella) was higher in the scheduled cohort. Patients with decreased Enterobacteriaceae demonstrated a greater ability to demonstrate a reduction in PN requirement, as well as attain positive growth. CONCLUSION: Scheduled antibiotics may alter the gut microbiome in children IF, which in turn may have an influence on important nutrition outcomes in pediatric IF. Further larger, multicenter studies are needed to determine the effect of scheduled antibiotics on the gut microbiome in this patient population and their overall effect on nutrition outcomes.

Risk models for predicting the health-related quality of life of caregivers of youth with gastrointestinal concerns.

PURPOSE: To determine the usefulness of cumulative and additive risk models in predicting the healthy-related quality of life (HRQOL) of caregivers of youth with chronic gastrointestinal conditions. METHODS: 203 caregivers (82.8% mothers; 77.3% white) of youth (M = 11.27 years; 44.3% female; 78.8% White) completed self-report questionnaires focused on potential environmental, child health, and family risk factors that could impact caregiver HRQOL. Cumulative risk models, evaluating overall combined risk level, as well as an additive risk model, exploring individual risk variables, were evaluated. RESULTS: Higher levels of cumulative risk were associated with poorer caregiver HRQOL after controlling for child and caregiver sex. A linear cumulative risk model was a better fit than a quadratic cumulative risk model for predicting caregiver HRQOL, while an additive model identified child HRQOL, child pain interference and family functioning as the most individually impactful risk variables. CONCLUSION: This study illustrates the usefulness of both additive and cumulative risk approaches in identifying caregivers at risk for poor HRQOL. Provision of appropriate referrals and interventions based on the caregiver's risk factors can help protect caregiver quality of life and, in turn, benefit the care children with chronic conditions receive at home.

Serum Transaminases at Presentation and Association with Acute Dialysis in Children with Hemolytic Uremic Syndrome.

Background: To determine whether serum transaminases at presentation predict the need for dialysis in children with hemolytic uremic syndrome (HUS). Methods: Single-center, retrospective chart review of pediatric patients with HUS. Data collected included demographics, clinical and laboratory parameters, and need for dialysis. These factors were compared between two groups: "dialysis" versus "no dialysis." Continuous data were compared using a t test whereas categoric data were compared by the chi-squared test. Multivariate logistic regression was performed on a prior set of variables to determine if serum transaminases independently predict the need for dialysis. Results: A total of 70 children were included in the study, of which, 39 (27%) received dialysis. The no-dialysis group had a higher proportion of white patients compared with the dialysis group (74% dialysis versus 94% no dialysis). The only clinical sign at admission associated with dialysis was reduced urine output (56% versus 16%, P<0.001). Univariate logistic regression identified admission serum creatinine, aspartate transaminase (AST), and alanine transaminase (ALT) to be associated with the need for dialysis. Multivariate logistic regression showed serum AST and ALT to be independent predictors of the need for dialysis, with both improving the performance of the regression model. Sensitivity analysis showed a cutoff of 129 U/L for AST and 83 U/L for ALT with high specificity. Conclusions: Serum transaminases at presentation are independently associated with the subsequent need for dialysis in patients with HUS. Our study suggests that when both serum ALT and AST are normal, the likelihood to need dialysis is very low; alternatively, when both serum ALT and AST are more than two times the upper level of normal, the need for dialysis is very high.

Key Determinants for Achieving Enteral Autonomy and Reduced Parenteral Nutrition Exposure in Pediatric Intestinal Failure.

BACKGROUND: We sought to evaluate the relationship between determinants of intestinal failure (IF) and achieving enteral autonomy from parenteral nutrition (PN) in a large single-center cohort of children. METHODS: This is a retrospective chart review of pediatric subjects enrolled in a database for the Center for Advanced Intestinal Rehabilitation at Children's of Alabama from 1989 to 2016. IF was defined as dependence on PN for >60 days. Subjects were included if they were followed since birth or infancy for a minimum of 3 months and sufficient documentation of study variables were available. Gestational age, race, diagnosis, anatomy (percent small and large bowel remaining, presence of ileocecal valve [ICV]), county of residence (rural/urban), and days of PN use were recorded. Kaplan-Meier curves and parametric survival regression models were used to investigate the relationship between the demographic and clinical variables with the length of PN use. RESULTS: Initially, 290 subjects were available to review. After inclusion/exclusion were applied, 158 subjects remained. Gestational age, diagnosis (necrotizing enterocolitis), small-bowel length (>50%), and presence of an ICV were all positive predictors for reaching enteral autonomy. Residual colon length was associated with shorter duration of PN in days. CONCLUSION: Enteral autonomy is a key outcome among children with IF. In our cohort, we found that gestational age, diagnosis, remaining small bowel, and presence of ICV are positive predictors for reaching this important milestone. Colon length is also an important factor with respect to duration of PN in days.

Evidence of Disturbed Sleep in Children With Eosinophilic Esophagitis and Persistent Epigastric Pain.

Objective: To determine whether the experience of persistent epigastric pain is associated with sleep disturbances in children with eosinophilic esophagitis (EoE). We hypothesized that children with EoE and persistent epigastric pain would (1) self-report greater current and worst pain severity, and (2) experience more disturbed sleep on objective and subjective measures in comparison with children with EoE but no persistent pain and healthy children. Methods: Fifty children with EoE were recruited for this cross-sectional study, of which 24 (48%) reported experiencing persistent epigastric pain. The remaining 26 (52%) children with EoE denied experiencing persistent pain. An additional 25 healthy children without EoE or persistent pain were included. All children provided severity ratings of current pain and worst pain experienced over the past week. Children then completed 12 consecutive nights of ambulatory sleep monitoring via actigraphy in the home. Caregivers provided information regarding their child's sleep patterns and internalizing symptoms. Results: Children with EoE and persistent pain reported significantly greater severity of current pain (p < .001) and worst pain over the past week (p < .001) compared with EoE without persistent pain and healthy children. Compared with the other groups, children with EoE and persistent pain also demonstrated greater actigraphic sleep disturbances, lower sleep efficiency (p = .004) and greater wake after sleep onset (p = .034). Conclusions: This study provides novel evidence that a significant proportion of children with EoE experience persistent symptoms of epigastric pain. Persistent pain was associated with significant sleep disturbances in children with EoE.

Disease-Related Predictors of Health-Related Quality of Life in Youth With Eosinophilic Esophagitis.

Objective: To evaluate relations between health-related quality of life (HRQoL) and clinical symptom presentation in youth with eosinophilic esophagitis (EoE). We hypothesized that presence of dysphagia, reflux, nausea/vomiting, and epigastric pain would be related to poorer HRQoL. In predictive models, it was hypothesized that dysphagia, reflux, nausea/vomiting, and epigastric pain would each significantly and uniquely predict poorer HRQoL. Methods: This cross-sectional, two-study design included 91 dyads comprised children with EoE and their respective caregivers across two tertiary children's hospitals, Site 1 in the Midwest (N = 47) and Site 2 in the Deep South (N = 44). Youth and their caregivers both completed questionnaires addressing HRQoL and EoE symptoms during clinic visits. Results: Per youth self-report, epigastric pain was found to be a significant predictor of poor physical and psychosocial HRQoL. Per caregiver-proxy reports, epigastric pain was found to be a significant predictor of poor physical HRQoL. Conclusions: The clinical symptoms of EoE, specifically epigastric pain, were found to be predictive of the youth's HRQoL. Targeted interventions to help youth with EoE better manage their specific symptom experiences could ultimately improve HRQoL.

Outcomes from a 12-Week, Open-Label, Multicenter Clinical Trial of Teduglutide in Pediatric Short Bowel Syndrome.

OBJECTIVE: To determine safety and pharmacodynamics/efficacy of teduglutide in children with intestinal failure associated with short bowel syndrome (SBS-IF). STUDY DESIGN: This 12-week, open-label study enrolled patients aged 1-17 years with SBS-IF who required parenteral nutrition (PN) and showed minimal or no advance in enteral nutrition (EN) feeds. Patients enrolled sequentially into 3 teduglutide cohorts (0.0125 mg/kg/d [n = 8], 0.025 mg/kg/d [n = 14], 0.05 mg/kg/d [n = 15]) or received standard of care (SOC, n = 5). Descriptive summary statistics were used. RESULTS: All patients experienced ≥1 treatment-emergent adverse event; most were mild or moderate. No serious teduglutide-related treatment-emergent adverse events occurred. Between baseline and week 12, prescribed PN volume and calories (kcal/kg/d) changed by a median of -41% and -45%, respectively, with 0.025 mg/kg/d teduglutide and by -25% and -52% with 0.05 mg/kg/d teduglutide. In contrast, PN volume and calories changed by 0% and -6%, respectively, with 0.0125 mg/kg/d teduglutide and by 0% and -1% with SOC. Per patient diary data, EN volume increased by a median of 22%, 32%, and 40% in the 0.0125, 0.025, and 0.05 mg/kg/d cohorts, respectively, and by 11% with SOC. Four patients achieved independence from PN, 3 in the 0.05 mg/kg/d cohort and 1 in the 0.025 mg/kg/d cohort. Study limitations included its short-term, open-label design, and small sample size. CONCLUSIONS: Teduglutide was well tolerated in pediatric patients with SBS-IF. Teduglutide 0.025 or 0.05 mg/kg/d was associated with trends toward reductions in PN requirements and advancements in EN feeding in children with SBS-IF. TRIAL REGISTRATION: ClinicalTrials.gov:NCT01952080; EudraCT: 2013-004588-30.

Quintuplets: 5 Cases of NEC. Are There Other Risk Factors?

OBJECTIVE: To review a case of quintuplets with all babies developing necrotizing enterocolitis. METHODS: A retrospective study of preterm quintuplets all developing necrotizing enterocolitis. Clinical outcomes were reviewed. RESULTS: Quintuplets were born at 24 weeks gestation. Each baby developed NEC and was treated. One baby died. Currently the remaining 4 infants are on full enteral nutrition. CONCLUSION: Further studies are needed to better understand this emerging population of multiple birth pregnancy and the frequency of NEC development.

A Heterozygous RAB27A Mutation Associated with Delayed Cytolytic Granule Polarization and Hemophagocytic Lymphohistiocytosis.

Frequently fatal, primary hemophagocytic lymphohistiocytosis (HLH) occurs in infancy resulting from homozygous mutations in NK and CD8 T cell cytolytic pathway genes. Secondary HLH presents after infancy and may be associated with heterozygous mutations in HLH genes. We report two unrelated teenagers with HLH and an identical heterozygous RAB27A mutation (c.259G→C). We explore the contribution of this Rab27A missense (p.A87P) mutation on NK cell cytolytic function by cloning it into a lentiviral expression vector prior to introduction into the human NK-92 cell line. NK cell degranulation (CD107a expression), target cell conjugation, and K562 target cell lysis was compared between mutant- and wild-type-transduced NK-92 cells. Polarization of granzyme B to the immunologic synapse and interaction of mutant Rab27A (p.A87P) with Munc13-4 were explored by confocal microscopy and proximity ligation assay, respectively. Overexpression of the RAB27A mutation had no effect on cell conjugate formation between the NK and target cells but decreased NK cell cytolytic activity and degranulation. Moreover, the mutant Rab27A protein decreased binding to Munc13-4 and delayed granzyme B polarization toward the immunologic synapse. This heterozygous RAB27A mutation blurs the genetic distinction between primary and secondary HLH by contributing to HLH via a partial dominant-negative effect.

Topical Review: Eosinophilic Esophagitis in Children: Implications for Health-Related Quality of Life and Potential Avenues for Future Research.

OBJECTIVE: To characterize the health-related quality of life (HRQoL) of children with eosinophilic esophagitis (EoE) as well as generate novel hypotheses for future research in this pediatric population. METHOD: A literature review was completed using PubMed and the keywords below. RESULTS: Research has shown that for children with EoE and their parents, symptom experiences and recommended treatments can have a negative impact on HRQoL. However, studies have yet to adequately address mechanisms that may help explain why this is. Areas of interest include sleep quality and disturbances, the experience of pain, and the presence of internalizing symptoms, all of which have the potential to uniquely and synergistically impact HRQoL. CONCLUSION: With greater understanding of the associations among sleep, pain, internalizing symptoms, and HRQoL in children with EoE may come enhanced therapies that substantially improve the quality of their health care.

Third transmembrane domain of the adrenocorticotropic receptor is critical for ligand selectivity and potency.

The ACTH receptor, known as the melanocortin-2 receptor (MC2R), plays an important role in regulating and maintaining adrenocortical function. MC2R is a subtype of the melanocortin receptor (MCR) family and has unique characteristics among MCRs. Endogenous ACTH is the only endogenous agonist for MC2R, whereas the melanocortin peptides α-, ß-, and γ-melanocyte-stimulating hormone and ACTH are full agonists for all other MCRs. In this study, we examined the molecular basis of MC2R responsible for ligand selectivity using ACTH analogs and MC2R mutagenesis. Our results indicate that substitution of Phe(7) with D-Phe or D-naphthylalanine (D-Nal(2')) in ACTH(1-24) caused a significant decrease in ligand binding affinity and potency. Substitution of Phe(7) with D-Nal(2') in ACTH(1-24) did not switch the ligand from agonist to antagonist at MC2R, which was observed in MC3R and MC4R. Substitution of Phe(7) with D-Phe(7) in ACTH(1-17) resulted in the loss of ligand binding and activity. Molecular analysis of MC2R indicated that only mutation of the third transmembrane domain of MC2R resulted in a decrease in D-Phe ACTH binding affinity and potency. Our results suggest that Phe(7) in ACTH plays an important role in ligand selectivity and that the third transmembrane domain of MC2R is crucial for ACTH selectivity and potency.

Structural insight into the MC4R conformational changes via different agonist-mediated receptor signaling.

The melanocortin-4 receptor (MC4R) plays a key role in the regulation of food intake and body weight. Previous studies indicate that α-melanocyte stimulating hormone (α-MSH) binds to MC4R and activates three signal pathways (cAMP, calcium, and mitogen-activated protein kinase pathways), whereas MC4R synthetic agonist THIQ can activate only the cAMP pathway. The molecular basis of the MC4R responsible for different ligand-mediated signaling is unknown. We hypothesize that different MC4R agonists can stabilize different MC4R conformations and result in ligand-mediated signal transduction. In this study, we examined the effect of the MC4R conformational change in cAMP signaling pathways mediated by different agonists by cross-linking two transmembrane helices (TM3 and TM6). We generated and tested 11 single and 8 double mutations that are located at the end of TM3 and beginning of TM6 in MC4R. Our results indicate that (1) single or double mutations of the MC4R did not significantly alter cAMP production induced by NDP-MSH compared to that of wild-type MC4R except single mutation 243H (the mutation 243H significantly decreased cAMP production mediated by NDP-MSH or THIQ due to a low level of receptor expression at the cell surface), (2) the mutation 247H significantly decreased THIQ-mediated cAMP production but not NDP-MSH, and (3) the receptor cAMP signaling pathway activation by THIQ is blocked in the presence of Zn(2+) with the double mutation I150/242H but activation by NDP-MSH is not, suggesting that the activated conformation of MC4R mediated by NDP-MSH and THIQ is different. This study provides insight into the molecular basis of MC4R responsible for receptor signaling mediated by different agonists.

Cytokines associated with necrotizing enterocolitis in extremely-low-birth-weight infants.

BACKGROUND: The goal was to identify cytokines associated with necrotizing enterocolitis (NEC). Based on our earlier reports of decreased tissue expression of transforming growth factor (TGF)-ß, we hypothesized that infants with NEC also have low blood TGF-ß levels. We further hypothesized that because fetal inflammation increases the risk of NEC, infants who develop NEC have elevated blood cytokine levels in early neonatal period. METHODS: Data on 104 extremely-low-birth-weight infants with NEC and 893 without NEC from 17 centers were analyzed. Clinical information was correlated with blood cytokine levels on postnatal day 1 (D1), D3, D7, D14, and D21. RESULTS: Male gender, non-Caucasian/non-African American ethnicity, sepsis, lower blood TGF-ß and interleukin (IL)-2 levels, and higher IL-8 levels were associated with NEC. The NEC group had lower TGF-ß levels than controls since D1. The diagnosis of NEC was associated with elevated IL-1ß, IL-6, IL-8, IL-10, monocyte chemoattractant protein-1/CC-motif ligand-2, macrophage inflammatory protein-1ß/CC-motif ligand-3, and C-reactive protein. CONCLUSION: Clinical characteristics, such as gender and ethnicity, and low blood TGF-ß levels are associated with higher risk of NEC. Infants who developed NEC did not start with high blood levels of inflammatory cytokines, but these rose mainly after the onset of NEC.

Baclofen for the treatment of pediatric GERD.

BACKGROUND AND AIM: Baclofen, a γ-aminobutyric acid receptor agonist, has been shown to reduce the episodes of gastroesophageal reflux (GER) by reducing the incidence of transient lower esophageal sphincter relaxations. Although baclofen has been shown to reduce reflux symptoms in adults, data in pediatric patients are limited. The aim of the study was to evaluate the efficacy of baclofen in children with refractory GER. METHODS: Medical charts of patients 1 to 18 years of age treated with baclofen for persistent GER symptoms were reviewed retrospectively. Short-term (at first clinic visit) and long-term (12 months) clinical responses were assessed. RESULTS: A total of 53 patients were included in the final analysis. The mean duration of illness was 1.5 years and the mean age was 6.1 years. All of the patients were taking either once- (53%) or twice-daily (47%) doses of proton pump inhibitors (PPIs) at the time of initiation of baclofen. Thirty-five (66%) patients experienced a significant reduction in clinical symptoms at their first follow-up visit. In the remaining 18 patients, however, baclofen was stopped because of either no response (n = 15) or adverse events (n = 3). A total of 27 patients continued treatment and were assessed for long-term response. Of those, 22 (81%) had a sustained response to baclofen at 12 months, whereas 5 (19%) lost response. We recognized no clinical characteristic differences between those with and without a response to baclofen at either time point. CONCLUSIONS: Baclofen can be used as supplemental therapy to proton pump inhibitors in children with refractory GER; however, prospective trials are needed to further validate our results and assess safety.

Mortality and intestinal failure in surgical necrotizing enterocolitis.

BACKGROUND/PURPOSE: To examine whether as initial surgical intervention for necrotizing enterocolitis, primary peritoneal drainage as compared to primary laparotomy is associated with increased mortality or intestinal failure. METHODS: Retrospective observational study of 240 infants with surgical necrotizing enterocolitis. RESULTS: There was no difference concerning the composite outcome of mortality before discharge or survival with intestinal failure after adjusting for known covariates (Odds Ratio 1.73, 95% CI 0.88, 3.40). More surviving infants in the peritoneal drainage with subsequent salvage or secondary laparotomy had intestinal failure compared to those who received a peritoneal drain without subsequent laparotomy and survived (12% vs. 14% vs. 1%, p=0.015). CONCLUSIONS: There is no difference between peritoneal drainage and laparotomy in infants with surgical necrotizing enterocolitis concerning the combined outcome of mortality or survival with intestinal failure. There is increased intestinal failure in surviving infants treated with peritoneal drain with either subsequent salvage or secondary laparotomy compared to peritoneal drainage alone.