Genomic Contributors to Esophageal Atresia and Tracheoesophageal Fistula: A 12 Year Retrospective Review

OBJECTIVE

To evaluate genetic testing utilization and diagnostic yield in infants with esophageal atresia (EA)/tracheoesophageal fistula (TEF) over the past 12 years to inform future practices and individualize prognostication and management.

STUDY DESIGN

A retrospective cohort study was performed for all infants with EA or EA/TEF hospitalized between January 2011 and January 2023 at a quaternary children's hospital. For each infant, demographic information, prenatal and postnatal history, and genetic testing were reviewed.

RESULTS

There were 212 infants who were classified as 1) complex/syndromic with EA/TEF plus an additional major anatomic anomaly (N=114, of which 74 met VACTERL criteria); 2) isolated/non syndromic EA/TEF (N=88) and 3) isolated/nonsyndromic EA (N=10). A range of genetic tests were sent with varying diagnostic rates including karyotype analysis in 12 (all with complex/syndromic phenotypes and all positive), chromosomal microarray analysis in 189 (114 of whom were complex/syndromic with an overall diagnostic rate of 3/189), single gene testing for CHD7 in 18 (4 positive), and exome analysis in 37 complex/syndromic patients (8 positive).

CONCLUSION

(s): EA/TEF with and without additional anomalies is genetically heterogeneous with a broad range of associated phenotypes. While the genetic etiology of EA/TEF with or without VACTERL remains largely unknown, genome wide testing (exome or genome) including copy number analysis is recommended over chromosomal microarray testing. We anticipate that expanded genetic/genomic testing modalities such as RNA sequencing and tissue specific molecular testing are needed in this cohort to improve our understanding of the genetic contributors to EA/TEF.

Trends in Histrelin Implantation at a Pediatric Tertiary Care Center

INTRODUCTION

Determine procedural outcomes and identify changing trends of utilization among patients undergoing histrelin implantation at a large pediatric tertiary care center over 15 y.

METHODS

Retrospective review of all patients undergoing histrelin implantation between January 2008 and April 2022.

RESULTS

A total of 746 patients underwent 1794 unique procedures (1364 placements/replacements, 430 removals). Procedures were performed in the clinic (1071, 60%), sedation unit (630, 35%), and operating room (93, 5%). A total of 14 (0.8%) complications were identified, including two patients that required early implant removal and one patient requiring antibiotics. Implants were placed for central precocious puberty (CPP, 579) or gender dysphoria (GD, 167). Cohort included 25.9% males and 74.1% females with mean age of implantation of 9.48 y (SD: 2.34, range: 1.05-17.34). The GD group is comprised of 52.4% males and 47.6% females, compared to 18.3% males and 81.7% females in the CPP. Significant difference was identified for mean age at placement by indication (CPP 8.65 y versus GD 12.34, P < 0.001). New patient referrals and implant procedures increased significantly over 14 y. Yearly frequency of patients receiving implants for CPP and GD increased significantly (P < 0.001), with proportion of GD patients increasing from 7% to 32%.

CONCLUSIONS

Histrelin procedures have increased in frequency overall with the greater increase noted in the GD cohort. The development of a streamlined process and a dedicated team have enabled histrelin procedures to be safely performed in the clinic setting for most, with a very low complication rate.

Primary sigmoidectomy and appendicostomy for chronic idiopathic constipation

PURPOSE

To present our experience in patients with chronic idiopathic constipation complicated by megarectosigmoid and fecal incontinence who underwent a primary sigmoidectomy and appendicostomy.

METHODS

We reviewed eight patients referred to the Colorectal Center from 2014 to 2016 with chronic idiopathic constipation and undergoing a sigmoidectomy and appendicostomy. We analyzed the previous medical treatment, indications for the surgical procedure, and outcomes.

RESULTS

Age at operation was 5-19 years. Time with constipation was 4-15 years. All patients received multiple laxatives, mainly polyethylene glycol, and all had severe social problems. Four patients have autism. The indication for surgery was an unsuccessful laxative trial, refusal to continue with rectal enemas or both, and social fear of continued fecal incontinence. Post-operatively, all patients were having daily bowel movements without fecal accidents.

CONCLUSION

Selected patients with chronic idiopathic constipation complicated by megarectosigmoid and fecal incontinence can obtain great benefit from primary sigmoidectomy and appendicostomy.

Interferon regulatory factor-2 is protective against hepatic ischemia-reperfusion injury

Interferon regulatory factor (IRF)-1 is a nuclear transcription factor that induces inflammatory cytokine mediators and contributes to hepatic ischemia-reperfusion (I/R) injury. No strategies to mitigate IRF1-mediated liver damage exist. IRF2 is a structurally similar endogenous protein that competes with IRF1 for DNA binding sites in IRF-responsive target genes and acts as a competitive inhibitor. However, the role of IRF2 in hepatic injury during hypoxic or inflammatory conditions is unknown. We hypothesize that IRF2 overexpression may mitigate IRF1-mediated I/R damage. Endogenous IRF2 is basally expressed in normal livers and is mildly increased by ischemia alone. Overexpression of IRF2 protects against hepatic warm I/R injury. Furthermore, we demonstrate that IRF2 overexpression limits production of IRF1-dependent proinflammatory genes, such as IL-12, IFNβ, and inducible nitric oxide synthase, even in the presence of IRF1 induction. Additionally, isograft liver transplantation with IRF2 heterozygote knockout (IRF2(+/-)) donor grafts that have reduced endogenous IRF2 levels results in worse injury following cold I/R during murine orthotopic liver transplantation. These findings indicate that endogenous intrahepatic IRF2 protein is protective, because the IRF2-deficient liver donor grafts exhibited increased liver damage compared with the wild-type donor grafts. In summary, IRF2 overexpression protects against I/R injury by decreasing IRF1-dependent injury and may represent a novel therapeutic strategy.

miR-375 inhibits autophagy and reduces viability of hepatocellular carcinoma cells under hypoxic conditions

BACKGROUND & AIMS

Tumor cells survive hypoxic conditions by inducing autophagy. We investigated the roles of microRNAs (miRNAs) in regulating autophagy of hepatocellular carcinoma (HCC) cells under hypoxic conditions.

METHODS

We used gain- and loss-of-function methods to evaluate the effect of miRNAs on autophagy in human HCC cell lines (Huh7 and Hep3B) under hypoxic conditions. Autophagy was quantified by immunoblot, immunofluoresence, and transmission electron microscopy analyses, and after incubation of cells with bafilomycin A1. We used a luciferase reporter assay to confirm associations between miRNAs and their targets. We analyzed growth of HCC xenograft tumors in nude mice.

RESULTS

miR-375 was down-regulated in HCC cells and tissues; it inhibited autophagy under hypoxic conditions by suppressing the conversion of LC3I to LC3II and thereby autophagic flux. The ability of miR-375 to inhibit autophagy was independent of its ability to regulate 3'-phosphoinositide-dependent protein kinase-1-AKT-mammalian target of rapamycin signaling, but instead involved suppression of ATG7, an autophagy-associated gene. miR-375 bound directly to a predicted site in the 3' untranslated region of ATG7. Up-regulating miR-375 or down-regulating ATG7 inhibited mitochondrial autophagy of HCC cells, reduced the elimination of damaged mitochondria under hypoxia, increased release of mitochondrial apoptotic proteins, and reduced viability of HCC cells. In mice, xenograft tumors that expressed miR-375 had fewer autophagic cells, larger areas of necrosis, and grew more slowly than tumors from HCC cells that expressed lower levels of miR-375.

CONCLUSIONS

miR-375 inhibits autophagy by reducing expression of ATG7 and impairs viability of HCC cells under hypoxic conditions in culture and in mice. miRNAs that inhibit autophagy of cancer cells might be developed as therapeutics.

Interferon regulatory factor-1 regulates the autophagic response in LPS-stimulated macrophages through nitric oxide

The pathogenesis of sepsis is complex and, unfortunately, poorly understood. The cellular process of autophagy is believed to play a protective role in sepsis; however, the mechanisms responsible for its regulation in this setting are ill defined. In the present study, interferon regulatory factor 1 (IRF-1) was found to regulate the autophagic response in lipopolysaccharide (LPS)-stimulated macrophages. In vivo, tissue macrophages obtained from LPS-stimulated IRF-1 knockout (KO) mice demonstrated increased autophagy and decreased apoptosis compared to those isolated from IRF-1 wild-type (WT) mice. In vitro, LPS-stimulated peritoneal macrophages obtained from IRF-1 KO mice experienced increased autophagy and decreased apoptosis. IRF-1 mediates the inhibition of autophagy by modulating the activation of the mammalian target of rapamycin (mTOR). LPS induced the activation of mTOR in WT peritoneal macrophages, but not in IRF-1 KO macrophages. In contrast, overexpression of IRF-1 alone increased the activation of mTOR and consequently decreased autophagic flux. Furthermore, the inhibitory effects of IRF-1 mTOR activity were mediated by nitric oxide (NO). Therefore, we propose a novel role for IRF-1 and NO in the regulation of macrophage autophagy during LPS stimulation in which IRF-1/NO inhibits autophagy through mTOR activation.

Dendritic cells and damage-associated molecular patterns: endogenous danger signals linking innate and adaptive immunity

Dendritic cells (DCs) are potent antigen-presenting cells critical in regulating the adaptive immune response. The role of DCs is dichotomous; they may both present antigens and the appropriate stimulatory molecules to initiate an adaptive immune response, or they may induce tolerance and release anti-inflammatory signals. The activation of immature DCs, required for the expression of the necessary costimulatory T cell molecules, is dependent on pattern recognition receptors. In addition to the pathogen-derived ligands of pattern recognition receptors, several damage-associated molecular patterns (DAMPs) have recently been shown to interact with DCs and dramatically affect their ultimate function. The complex interplay of DAMPs on DCs is clinically important, with implications for transplantation, tumor immunity, autoimmunity, chronic inflammation and other conditions of sterile inflammation such as ischemia reperfusion injury. In this review, we will focus on the role of DAMPs in DC function.

Endogenous histones function as alarmins in sterile inflammatory liver injury through Toll-like receptor 9 in mice

Sterile inflammatory insults are known to activate innate immunity and propagate organ damage through the recognition of extracellular damage-associated molecular pattern (DAMP) molecules. Although DAMPs such as endogenous DNA and nuclear high-mobility group box 1 have been shown to be critical in sterile inflammation, the role of nuclear histone proteins has not yet been investigated. We report that endogenous histones function as DAMPs after ischemic injury through the pattern recognition receptor Toll-like receptor (TLR) 9 to initiate inflammation. Using an in vivo model of hepatic ischemia/reperfusion (I/R) injury, we show that levels of circulating histones are significantly higher after I/R, and that histone neutralization significantly protects against injury. Injection of exogenous histones exacerbates I/R injury through cytotoxic effects mediated by TLR9 and MyD88. In addition, histone administration increases TLR9 activation, whereas neither TLR9 nor MyD88 mutant mice respond to exogenous histones. Furthermore, we demonstrate in vitro that extracellular histones enhance DNA-mediated TLR9 activation in immune cells through a direct interaction.

CONCLUSION

These novel findings reveal that histones represent a new class of DAMP molecules and serve as a crucial link between initial damage and activation of innate immunity during sterile inflammation.

Validation of a lactic acid- and citric acid-based antimicrobial product for the reduction of Escherichia coli O157: H7 and Salmonella on beef tips and whole chicken carcasses

The objectives of this study were to determine the effects of a lactic acid- and citric acid-based antimicrobial product on the reduction of Salmonella on whole broiler carcasses during processing and the reduction of Salmonella and Escherichia coli O157:H7 on beef trim. Freshly harvested broiler carcasses were inoculated with an inoculum of Salmonella strains to yield a 10(5) CFU/ml pathogen load on the surface of the carcass. The beef tips were inoculated as well with an inoculum of either E. coli O157:H7 or Salmonella to yield 10(4) CFU/100 cm(2). After 30 min for attachment, the broiler carcasses were treated with Chicxide applied for 5 s via a spray or immersed in Chicxide for 5, 10, or 20 s. Broiler carcasses were rinsed in poultry rinse bags with 400 ml of Butterfield's phosphate buffer in which Salmonella was enumerated from the diluents and Butterfield's phosphate. Chicxide significantly reduced Salmonella by 1.3 log CFU/ml with spray treatment and 2.3 log CFU/ml for all dip treatments. Following 30 min of attachment, the beef tips were placed into a spray cabinet with either Beefxide or sterilized water (control) and sprayed at 1 ft/2.5 s chain speed at 40 lb/in(2). The external surface of each beef tip was swabbed (100 cm(2)) to determine pathogen loads. Beefxide significantly reduced E. coli O157:H7 by 1.4 log CFU/100 cm(2) and Salmonella by 1.1 log CFU/100 cm(2) (P < 0.05) compared with the control samples.

Iron(III)--phosphoprotein chelates: stoichiometric equilibrium constant for interation of iron(III) and phosphorylserine residues of phosvitin and casein

Estimates of the strength of iron binding to model phosphoproteins were obtained from equilibrium dialysis experiments. Iron-free phosvitin (chicken and frog) or alpha sl-casein (cow) was dialyzed against the iron(III) chelates of nitrilotriacetate (NTA), )ethylenedinitrilo)tetraacetate (EDTA), or citrate. Protein-bound metal was measured at equilibrium; competition of chelator and phosphoprotein for iron(III) was determined by reference to comprehensive equilibrium equations presented in the Appendix. Analysis of the iron-binding data for phosvitin suggested that clusters of di-O-phosphorylserine residues (SerP.SerP) were the most probable iron-binding sites. A stoichiometric equilibrium constant of 10(18.0) was calculated for the formation of the Fe3+(SerP.SerP) chelate. When comared on the basis of phosphate content, casein bound iron more weakly than phosvitin. However, if the stoichiometric equilibrium constant for the formation of the casein Fe3+(SerP.SerP) chelate (10(17.5) was adjusted to account for the fact that a smaller percentage of casein phosphoserines occurs in di-O-phosphorylserine clusters, the affinity of casein and phosvitin for iron was very similar. A theoretical comparison showed that the "strengths" of the ferric chelates can be ranked: EDTA greater than phosphoprotein di-O-phosphorylserine greater than citrate greater than NTA.