CD177+ cells produce neutrophil extracellular traps that promote biliary atresia

BACKGROUND & AIMS

We have previously reported on the potential pathogenic role of neutrophils in biliary atresia (BA). Herein, we aimed to delineate the role of CD177+ neutrophils in the pathogenesis of BA.

METHODS

Immune cells from the livers of mice with rhesus rotavirus-induced BA were analysed. Single-cell RNA-sequencing was performed to specifically analyse Gr-1⁺ (Ly6C/Ly6G⁺) cells in the liver. Gene expression profiles of CD177⁺ cells were analysed using the Smart-Seq RNA-sequencing method, and the pathogenesis of BA was examined in Cd177^-/- mice. Neutrophil extracellular trap (NET) inhibitors were used to determine the role of CD177⁺ cell-derived NETs in BA-associated bile duct damage, and a pilot clinical study evaluated the potential effects of N-acetylcysteine on NET release in BA.

RESULTS

Increased levels of Gr-1⁺ cells were observed in the livers of mice with rhesus rotavirus-induced BA. RNA-sequencing analysis revealed that CD177⁺ cells were the main population of Gr-1⁺ cells and expressed elevated levels of both interferon-stimulated and neutrophil degranulation genes. Cd177^-/- BALB/c mice exhibited delayed disease onset and reduced morbidity and mortality. High numbers of mitochondria were detected in CD177⁺ cells derived from mice with BA; these cells were associated with increased levels of reactive oxygen species and increased NET formation, which induced the apoptosis of biliary epithelial cells in cocultures. In a pilot clinical study, the administration of N-acetylcysteine to patients with BA reduced CD177⁺ cell numbers and reactive oxygen species levels, indicating a potential beneficial effect.

CONCLUSIONS

Our data indicate that CD177⁺ cells play an important role in the initiation of BA pathogenesis via NET formation.

CLINICAL TRIAL REGISTRATION

The pilot study of N-acetylcysteine treatment in patients with BA was registered on the Chinese Clinical Trial Registry (ChiCTR2000040505).

LAY SUMMARY

Neutrophils (a type of innate immune cell, i.e. an immune cell that doesn't target a specific antigen) are thought to play a role in the development of biliary atresia (a rare but potentially lethal condition of the bile ducts that occurs in infants). Herein, we found that neutrophils expressing a particular protein (CD177) played an important role in bile duct damage by releasing a special structure (NET) that can trap and kill pathogens but that can also cause severe tissue damage. A pilot study in patients with biliary atresia showed that inhibiting NETs could have a beneficial effect.

Pattern of anatomic disorder and surgical management of anorectal prolapse in anorectal malformation

AIM

Due to the paucity of data and controversy regarding the etiology and surgical approach for managing anorectal prolapse (ARP) after anorectoplasty, we sought to investigate the underlying anatomic disorder and the surgical outcome in managing this challenging complication.

METHODS

We performed a retrospective study on 83 patients with ARP related to anorectal malformations (ARM). Logistic regression analyses were performed to detect the risk factors for the ARP severity. Surgical procedures were stratified according to identified anatomical abnormalities and surgical outcomes were analyzed.

RESULTS

50 patients (62.7%) had high-type ARM. The original anorectoplasty had a higher rate of ARP in laparoscopic-assisted anorectoplasty (n = 49, 59.0%) versus posterior sagittal anorectoplasty (n = 11, 13.3%). ARP was associated with rectal fat hyperplasia (67.5%), dilated muscular tunnel (79.5%), longitudinal muscle (LM) discontinuity (16.9%), rectal dilation (22.9%), mislocated anus (7.2%), and excessive mobile mesorectum (3.6%). Based on the ARP severity, the patients were divided into a severe group (Group 1, n = 38) and a moderate group (Group 2, n = 45). Binary logistic regression analysis showed that hyperplasia rectal fat (OR 4.55, 95% CI 1.16-17.84), rectal dilation (OR 4.21, 95% CI 1.05-16.94), and high-type ARM (OR 2.90, 95% CI 1.14-7.39) were independent risk factors for the development of severe ARP. Complications after stratified surgical repair included wound infection in six patients (7.2%), anal stenosis in one patient (1.2%), and ARP recurrence in two patients (2.4%). Twenty-six patients without colostomy before prolapse repair were followed up for 2 to 12 years. All the patients maintained voluntary bowel movements. Following ARP repair, there was an overall higher rate of no soiling or grade 1 soiling (88.5 vs. 65.4%), but 3 of 12 patients with grade 2 constipation were upgraded to grade 3.

CONCLUSION

Our study shows that ARM-related anorectal prolapse is associated with excessive rectum, hyperplasia of rectal fat, mobile mesorectum, loose muscular tunnel, LM discontinuity, and anal mislocation. Surgical repair with techniques stratified according to the patients' underlying risk factors is effective to prevent recurrence and improve the soiling continence.

Direct Interaction of Sox10 With Cadherin-19 Mediates Early Sacral Neural Crest Cell Migration: Implications for Enteric Nervous System Development Defects

BACKGROUND AND AIMS

The enteric nervous system, which regulates many gastrointestinal functions, is derived from neural crest cells (NCCs). Defective NCC migration during embryonic development may lead to enteric neuropathies such as Hirschsprung's disease (hindgut aganglionosis). Sox10 is known to be essential for cell migration but downstream molecular events regulating early NCC migration have not been fully elucidated. This study aimed to determine how Sox10 regulates migration of sacral NCCs toward the hindgut using Dominant megacolon mice, an animal model of Hirschsprung's disease with a Sox10 mutation.

METHODS

We used the following: time-lapse live cell imaging to determine the migration defects of mutant sacral NCCs; genome-wide microarrays, site-directed mutagenesis, and whole embryo culture to identify Sox10 targets; and liquid chromatography and tandem mass spectrometry to ascertain downstream effectors of Sox10.

RESULTS

Sacral NCCs exhibited retarded migration to the distal hindgut in Sox10-null embryos with simultaneous down-regulated expression of cadherin-19 (Cdh19). Sox10 was found to bind directly to the Cdh19 promoter. Cdh19 knockdown resulted in retarded sacral NCC migration in vitro and ex vivo, whereas re-expression of Cdh19 partially rescued the retarded migration of mutant sacral NCCs in vitro. Cdh19 formed cadherin-catenin complexes, which then bound to filamentous actin of the cytoskeleton during cell migration.

CONCLUSIONS

Cdh19 is a direct target of Sox10 during early sacral NCC migration toward the hindgut and forms cadherin-catenin complexes which interact with the cytoskeleton in migrating cells. Elucidation of this novel molecular pathway helps to provide insights into the pathogenesis of enteric nervous system developmental defects.

Vulnerability and resilience in children during the COVID-19 pandemic

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic is having a profound impact on the health and development of children worldwide. There is limited evidence on the impact of COVID-19 and its related school closures and disease-containment measures on the psychosocial wellbeing of children; little research has been done on the characteristics of vulnerable groups and factors that promote resilience.

METHODS

We conducted a large-scale cross-sectional population study of Hong Kong families with children aged 2-12 years. Parents completed an online survey on family demographics, child psychosocial wellbeing, functioning and lifestyle habits, parent-child interactions, and parental stress during school closures due to COVID-19. We used simple and multiple linear regression analyses to explore factors associated with child psychosocial problems and parental stress during the pandemic.

RESULTS

The study included 29,202 individual families; of which 12,163 had children aged 2-5 years and 17,029 had children aged 6-12 years. The risk of child psychosocial problems was higher in children with special educational needs, and/or acute or chronic disease, mothers with mental illness, single-parent families, and low-income families. Delayed bedtime and/or inadequate sleep or exercise duration, extended use of electronic devices were associated with significantly higher parental stress and more psychosocial problems among pre-schoolers.

CONCLUSIONS

This study identifies vulnerable groups of children and highlights the importance of strengthening family coherence, adequate sleep and exercise, and responsible use of electronic devices in promoting psychosocial wellbeing during the COVID-19 pandemic.

Assessment of SARS-CoV-2 Immunity in Convalescent Children and Adolescents

Persistence of protective immunity for SARS-CoV-2 is important against reinfection. Knowledge on SARS-CoV-2 immunity in pediatric patients is currently lacking. We opted to assess the SARS-CoV-2 adaptive immunity in recovered children and adolescents, addressing the pediatrics specific immunity towards COVID-19. Two independent assays were performed to investigate humoral and cellular immunological memory in pediatric convalescent COVID-19 patients. Specifically, RBD IgG, CD4+, and CD8+ T cell responses were identified and quantified in recovered children and adolescents. SARS-CoV-2-specific RBD IgG detected in recovered patients had a half-life of 121.6 days and estimated duration of 7.9 months compared with baseline levels in controls. The specific T cell response was shown to be independent of days after diagnosis. Both CD4+ and CD8+ T cells showed robust responses not only to spike (S) peptides (a main target of vaccine platforms) but were also similarly activated when stimulated by membrane (M) and nuclear (N) peptides. Importantly, we found the differences in the adaptive responses were correlated with the age of the recovered patients. The CD4+ T cell response to SARS-CoV-2 S peptide in children aged <12 years correlated with higher SARS-CoV-2 RBD IgG levels, suggesting the importance of a T cell-dependent humoral response in younger children under 12 years. Both cellular and humoral immunity against SARS-CoV-2 infections can be induced in pediatric patients. Our important findings provide fundamental knowledge on the immune memory responses to SARS-CoV-2 in recovered pediatric patients.

Biliary Atresia - emerging diagnostic and therapy opportunities

Biliary Atresia is a devastating pediatric cholangiopathy affecting the bile ducts of the liver. In this review, we describe recent progress in the understanding of liver development with a focus on cholangiocyte differentiation and how use of technical platforms, including rodent, zebrafish and organoid models, advances our understanding of Biliary Atresia. This is followed by a description of potential pathomechanisms, such as autoimmune responses, inflammation, disturbed apical-basal cell polarity, primary cilia dysfunction as well as beta-amyloid accumulation. Finally, we describe current and emerging diagnostic opportunities and recent translation breakthroughs for Biliary Atresia in the area of emerging therapy development, including immunomodulation and organoid-based systems for liver and bile duct repair.

Multilevel Factors Affecting Healthcare Workers' Perceived Stress and Risk of Infection During COVID-19 Pandemic

Objectives: This study aimed to identify key factors affecting Healthcare workers (HCWs) perceived stress and risk of contracting COVID-19 among themselves and their family members during the pandemic. Methods: A cross-sectional online questionnaire study was conducted between 19 March and April 5, 2020 in Hong Kong. HCWs from public hospitals and private dentists, and their family members participated. Results: A total of 747 HCWs and 245 family members participated. Higher perceived stress in HCWs was associated with more negative changes in family relationship (p = 0.025). The HCWs' perceived stress, however, was positively associated with family cohesion (p = 0.033) and stress levels of family members (p < 0.001). The level of HCWs' satisfaction toward the hospital policies in response to the COVID-19 outbreak was associated with lower levels of perceived stress and risk of themselves or their family members contracting COVID-19. HCWs' previous frontline experience of SARS was significantly associated with less perceived risk of themselves or their family members contracting COVID-19. Conclusion: Hospital policies addressing HCWs' needs, frontline experience of SARS, and family relationship influenced psychological wellbeing of HCWs during the COVID-19 outbreak.

Size matters: Large copy number losses in Hirschsprung disease patients reveal genes involved in enteric nervous system development

Hirschsprung disease (HSCR) is a complex genetic disease characterized by absence of ganglia in the intestine. HSCR etiology can be explained by a unique combination of genetic alterations: rare coding variants, predisposing haplotypes and Copy Number Variation (CNV). Approximately 18% of patients have additional anatomical malformations or neurological symptoms (HSCR-AAM). Pinpointing the responsible culprits within a CNV is challenging as often many genes are affected. Therefore, we selected candidate genes based on gene enrichment strategies using mouse enteric nervous system transcriptomes and constraint metrics. Next, we used a zebrafish model to investigate whether loss of these genes affects enteric neuron development in vivo.

This study included three groups of patients, two groups without coding variants in disease associated genes: HSCR-AAM and HSCR patients without associated anomalies (HSCR-isolated). The third group consisted of all HSCR patients in which a confirmed pathogenic rare coding variant was identified. We compared these patient groups to unaffected controls. Predisposing haplotypes were determined, confirming that every HSCR subgroup had increased contributions of predisposing haplotypes, but their contribution was highest in isolated HSCR patients without RET coding variants. CNV profiling proved that specifically HSCR-AAM patients had larger Copy Number (CN) losses. Gene enrichment strategies using mouse enteric nervous system transcriptomes and constraint metrics were used to determine plausible candidate genes located within CN losses. Validation in zebrafish using CRISPR/Cas9 targeting confirmed the contribution of UFD1L, TBX2, SLC8A1, and MAPK8 to ENS development. In addition, we revealed epistasis between reduced Ret and Gnl1 expression and between reduced Ret and Tubb5 expression in vivo. Rare large CN losses—often de novo—contribute to HSCR in HSCR-AAM patients. We proved the involvement of six genes in enteric nervous system development and Hirschsprung disease.

Hirschsprung disease is a congenital disorder characterized by the absence of intestinal neurons in the distal part of the intestine. It is a complex genetic disorder in which multiple variations in our genome combined, result in disease. One of these variations are Copy Number Variations (CNVs): large segments of our genome that are duplicated or deleted. Patients often have Hirschsprung disease without other symptoms. However, a proportion of patients has additional associated anatomical malformations and neurological symptoms. We found that CNVs, present in patients with associated anomalies, are more often larger compared to unaffected controls or Hirschsprung patients without other symptoms. Furthermore, Copy Number (CN) losses are enriched for constrained coding regions (CCR; genes usually not impacted by genomic alterations in unaffected controls) of which the expression is higher in the developing intestinal neurons compared to the intestine. We modelled loss of these candidate genes in zebrafish by disrupting the zebrafish orthologues by genome editing. For several genes this resulted in changes in intestinal neuron development, reminiscent of HSCR observed in patients. The results presented here highlight the importance of Copy Number profiling, zebrafish validation and evaluating all CCR expressed in developing intestinal neurons during diagnostic evaluation.

Determining the optimal timing of liver transplant for pediatric patients after Kasai portoenterostomy based on disease severity scores

BACKGROUND

The objective of this study was to determine the most optimal timing of liver transplant (LT) for post-Kasai portoenterostomy (KPE) patients based on disease severity scores.

METHODS

This was a retrospective study and the clinical data of all LT recipients aged <18 years (n = 89) with a history of KPE were analyzed. They were divided into three groups according to their PELD/MELD scores at the time of LT (A: <15; B: 15-25; C: >25). The effects of LT on the clinical outcomes and hospitalization status were analyzed.

RESULTS

There were 33, 34 and 22 patients in group A, B and C, respectively. There was no significant difference in 3-year graft survival rate between the three groups but group C patients had the highest incidence of vascular or biliary complications (p = 0.022). Group C patients had a significantly lower hospital admission frequency (p = 0.036) and shorter hospital stay (p = 0.041) after LT when compared with their pre-LT status and with non-LT patients with similar disease severity scores. On the other hand, the hospitalization frequency and duration were similar in patients with the lowest disease severity score (group A) before, after and without LT.

CONCLUSIONS

The benefit of LT was less obvious when the disease severity score is <15. A high complication rate was reported when LT was performed at a score > 25. Donor availability, the patient's general condition and parental wish should be considered during individual assessment.

TYPE OF STUDY

Clinical research paper.

LEVEL OF EVIDENCE

Level III.

A Comparison Between Chinese Children Infected with Coronavirus Disease-2019 and with Severe Acute Respiratory Syndrome 2003

OBJECTIVES

To compare the clinical and laboratory features of severe acute respiratory syndrome 2003 (SARS) and coronavirus disease 2019 (COVID-19) in 2 Chinese pediatric cohorts, given that the causative pathogens and are biologically similar.

STUDY DESIGN

This is a cross-sectional study reviewing pediatric patients with SARS (n = 43) and COVID-19 (n = 244) who were admitted to the Princess Margaret Hospital in Hong Kong and Wuhan Children's Hospital in Wuhan, respectively. Demographics, hospital length of stay, and clinical and laboratory features were compared.

RESULTS

Overall, 97.7% of patients with SARS and 85.2% of patients with COVID-19 had epidemiologic associations with known cases. Significantly more patients with SARS developed fever, chills, myalgia, malaise, coryza, sore throat, sputum production, nausea, headache, and dizziness than patients with COVID-19. No patients with SARS were asymptomatic at the time of admission, whereas 29.1% and 20.9% of patients with COVID-19 were asymptomatic on admission and throughout their hospital stay, respectively. More patients with SARS required oxygen supplementation than patients with COVID-19 (18.6 vs 4.7%; P = .004). Only 1.6% of patients with COVID-19 and 2.3% of patients with SARS required mechanical ventilation. Leukopenia (37.2% vs 18.6%; P = .008), lymphopenia (95.4% vs 32.6%; P < .01), and thrombocytopenia (41.9% vs 3.8%; P < .001) were significantly more common in patients with SARS than in patients with COVID-19. The duration between positive and negative nasopharyngeal aspirate and the length in hospital stay were similar in patients with COVID-19, regardless of whether they were asymptomatic or symptomatic, suggesting a similar duration of viral shedding.

CONCLUSIONS

Children with COVID-19 were less symptomatic and had more favorable hematologic findings than children with SARS.

Haematological and immunological data of Chinese children infected with coronavirus disease 2019

Haematological and immunological data of children with COVID-19 infection is lacking. Between 21st January and 20th March 2020, 244 children who were confirmed to have COVID-19 infection and admitted to the Wuhan Children's Hospital, China were retrospectively reviewed. 193 children were considered as symptomatic, which was defined as having either the presence of clinical symptoms or the presence of CT thorax abnormalities. Their haematological and immunological profiles, including complete blood counts, lymphocyte subsets (T, B and NK cell counts), immunoglobulin (Ig) profiles (IgG, IgA and IgM) and cytokine profiles were analysed and compared between the symptomatic and asymptomatic groups. The median values and the interquartile ranges were calculated. Comparison was made using the Mann–Whitney U test. Children with symptomatic COVID-19 infection had significantly lower haemoglobin levels, but higher absolute lymphocyte and monocyte counts, IgG and IgA levels, as well as interleukin 6 (IL-6), IL-10, tumour necrosis factor alpha and interferon gamma levels. The obtained data will be utilized for further studies in comparing children and adults with COVID-19 infections in other parts of the world and with different severity .

Laparoscopic surgical technique to enhance the management of anorectal malformations: 330 cases' experience in a single center

PURPOSE

Laparoscopic-assisted anorectoplasty (LAARP) is considered to benefit the patients with vesico-prostatic fistula. The aim of this study is to present the details of our LAARP technique for improving the short- and long-term outcomes in the patients with high and intermediate types of anorectal malformations (ARMs).

METHODS

330 patients with high-type (174 cases) and intermediate-type (156 cases) anorectal malformation (aged 8 days to 15 years) underwent LAARP from 2001 to 2019. LAARP was performed for full mobilization and resection of the dilated rectum, intra-rectal closure of the fistula, visualization, and enlargement of the center of the longitudinal muscle tube (LMT) from pelvic and perineal aspects.

RESULTS

LAARP was performed in all patients and no patient was converted to open procedure. The urethral diverticulum was found in three patients (1.02%, 3/294) according to postoperative protocol voiding cystourethrogram but was not associated with any symptoms such as urinary tract infection and dysuria. Rectal prolapse requiring surgical intervention developed in 25 (7.6%) of 330 patients. Anal stricture occurred in three patients and re-do anoplasty was performed 5 months after LAARP. Anal retraction occurred in two patients and re-pull-through was conducted at 5 and 6 days, respectively, after LAARP. 228 patients who were older than 3 years were followed up. The median follow-up period was 5.8 years (range 3-15 years). 217 patients (95.2%) had voluntary bowel movements; 202 patients (88.6%) were free from soiling or with grade 1 soiling; 30 patients (13.6%) and 25 patients (11.3%) suffered from grade 1 and grade 2 constipation, respectively, while no patient had grade 3 constipation.

CONCLUSION

Our experience demonstrates that the LAARP has advantages on rectal mobilization and resection, intra-rectal fistula closure and accurate tunnel formation in the LMT with minimal trauma. The improvement of the short-term and long-term outcomes after LAARP has been shown not only for high-type ARM but also for intermediate-type ARM.

Quality of life and defecative function 10 years or longer after posterior sagittal anorectoplasty and laparoscopic-assisted anorectal pull-through for anorectal malformation

PURPOSE

In our center, patients with anorectal malformation, including males with recto-vesical (RV)/recto-bladder neck (RBN)/recto-prostatic urethral (RU) fistulas, and females with recto-vaginal (RV) fistulas have been treated by posterior sagittal anorectoplasty (PSARP) before 2000, and by laparoscopic-assisted anorectal pull-through (LAARP) thereafter. We would like to compare the quality of life (QOL) and long-term defecative function between these two groups of patients 10 years after reconstructive surgery.

METHODS

Patients who underwent LAARP between 2001 and 2005 were compared with historical controls treated with PSARP between 1996 and 2000. Degrees of continence were graded by the Krickenbeck classification and Kelly's score. QOL was assessed by Hirschsprung's disease/Anorectal Malformation Quality of Life (HAQL) questionnaire. Results were compared using Chi-square test and t test.

RESULTS

There were 14 LAARP and 7 PSARP patients. All attained voluntary bowel movements. Moderate to severe soiling (Krickenbeck Grade 2 and 3) was found in 3/14 LAARP (21.4%) and 1/7 PSARP (14.3%) patients, p = 1.00. Constipation requiring use of laxatives was present in 3/14 LAARP (28.6%) and 1/7 PSARP (14.3%) patients, p = 0.62. Mean Kelly's scores were 3.79 ± 0.98 (LAARP) and 4.71 ± 1.25 (PSARP), p = 0.12. No patient required Malone antegrade continence enema (MACE). The QOL scores based on the HAQL questionnaire were comparable between the two groups in all areas except social functioning, in which the LAARP patients attained a significantly lower mean score (26.4 vs 71.7, p = 0.0001).

CONCLUSION

The 10-year outcome between LAARP and PSARP patients in terms of QOL and defecative function is comparable. Impairment in social functioning in these patients is reflected by the self-reported lower level of functioning.

Recent trends in the prevalence of Helicobacter Pylori in symptomatic children: A 12-year retrospective study in a tertiary centre

OBJECTIVE

Helicobacter pylori infection is common among Asians. However, evidence in the recent years has demonstrated a decrease in the prevalence of H. pylori infection among children and adults worldwide. Our aim was to update its prevalence in symptomatic children in our locality in the recent 12 years and compared to the results of our previous review published in 2005.

METHODS

A retrospective review was carried out between 2005 and 2017. All children who presented with dyspepsia or gastrointestinal bleeding and underwent oesophagogastroduodenoscopy with antral biopsy taken were included. Patient demographics, endoscopic, or histological diagnosis and the H. pylori status were recorded.

MAIN RESULTS

A total of 602 patients were included. There was a statistically significant decreasing trend of H. pylori infection rate between 2005 and 2017 (p = 0.003). The overall infection rate from this study was 12.8%, compared to 25.6% from our previous review. Overall failure of eradication with first-line antibiotic therapy has increased to 29.3% from 10% in our previous review.

CONCLUSION

There was a decrease in the prevalence of H. pylori infection among symptomatic children for the recent 12 years, comparing to our previous data from 2005. We hypothesize that the reduction in prevalence of H. pylori infection among adults and the decrease in the practice of sharing chopsticks during meals have led to a decrease in transmission of the bacteria among family members in Hong Kong. However, the failure of eradication with first line treatment was higher, possibly due to the increase in antibiotics usage and resistance.

LEVEL OF EVIDENCE

III.

De novo mutations in Caudal Type Homeo Box transcription Factor 2 (CDX2) in patients with persistent cloaca

The cloaca is an embryonic cavity that is divided into the urogenital sinus and rectum upon differentiation of the cloacal epithelium triggered by tissue-specific transcription factors including CDX2. Defective differentiation leads to persistent cloaca in humans (PC), a phenotype recapitulated in Cdx2 mutant mice. PC is linked to hypo/hyper-vitaminosis A. Although no gene has ever been identified, there is a strong evidence for a genetic contribution to PC. We applied whole-exome sequencing and copy-number-variants analyses to 21 PC patients and their unaffected parents. The damaging p.Cys132* and p.Arg237His de novo CDX2 variants were identified in two patients. These variants altered the expression of CYP26A1, a direct CDX2 target encoding the major retinoic acid (RA)-degrading enzyme. Other RA genes, including the RA-receptor alpha, were also mutated. Genes governing the development of cloaca-derived structures were recurrently mutated and over-represented in the basement-membrane components set (q-value < 1.65 × 10-6). Joint analysis of the patients' profile highlighted the extracellular matrix-receptor interaction pathway (MsigDBID: M7098, FDR: q-value < 7.16 × 10-9). This is the first evidence that PC is genetic, with genes involved in the RA metabolism at the lead. Given the CDX2 de novo variants and the role of RA, our observations could potentiate preventive measures. For the first time, a gene recapitulating PC in mouse models is found mutated in humans.

The Role of Neonatal Gr-1+ Myeloid Cells in a Murine Model of Rhesus-Rotavirus-Induced Biliary Atresia

Activation of innate immunity together with cholangiocyte damage occurs in biliary atresia (BA). However, detailed information on the inflammatory cells involved is lacking. This study investigates both the pathophysiology of CD11b⁺Gr-1⁺ cells in a mouse model of BA and their presence in BA patients. CD11b⁺Gr-1⁺ cells were targeted by an anti-Ly6G antibody in murine BA induced by inoculation with rhesus rotavirus. Expression of the Ly6G homolog CD177⁺ was examined in biopsies from BA patients. The symptoms of BA were ameliorated, and survival was prolonged in those mice receiving 5 to 10 μg of antibody per mouse every 3 days for four times compared with the mice treated with virus alone. However, the mice later developed chronic BA with persistent low body weight and jaundice. Hepatic inflammatory cells were reduced compared with acute BA. Blockade of extrahepatic bile ducts occurred, whereas intrahepatic ductules were partially preserved, and a progressive increase in liver fibrosis was observed. High levels of CD11b⁺Gr-1⁺ cells were present in these mice. The administration of an anti-Ly6G antibody again in those chronic BA mice reduced jaundice and restored body weight. In BA patients CD177⁺ cells were highly expressed in the liver. Our data suggest that the chronic mouse BA model shares key characteristics with clinical BA and indicates the importance of CD11b⁺Gr-1⁺ cells in the initiation and progression of BA.

Cholangiopathies - Towards a molecular understanding

Liver diseases constitute an important medical problem, and a number of these diseases, termed cholangiopathies, affect the biliary system of the liver. In this review, we describe the current understanding of the causes of cholangiopathies, which can be genetic, viral or environmental, and the few treatment options that are currently available beyond liver transplantation. We then discuss recent rapid progress in a number of areas relevant for decoding the disease mechanisms for cholangiopathies. This includes novel data from analysis of transgenic mouse models and organoid systems, and we outline how this information can be used for disease modeling and potential development of novel therapy concepts. We also describe recent advances in genomic and transcriptomic analyses and the importance of such studies for improving diagnosis and determining whether certain cholangiopathies should be viewed as distinct or overlapping disease entities.

Congenital pulmonary airway malformation: advances and controversies

Advances in antenatal screening have provided evidence that the prevalence of congenital pulmonary airway malformation is higher than previously thought. This means that, on a global scale, more congenital pulmonary airway malformations will be diagnosed and seen by clinicians across many different specialties. This increase poses new controversies and challenges for clinicians in terms of prenatal and postnatal management. Important and exciting research has begun to emerge in the past decade. This Review describes current understanding of the disease, the latest surgical developments, and highlights management issues and controversies, including the rationale and timing of surgical intervention, the choice of surgical approach, and long-term functional outcomes. In doing so, we attempt to provide a balanced management algorithm for readers.

Advances in paediatric gastroenterology

Recent developments in paediatric gastrointestinal surgery have focused on minimally invasive surgery, the accumulation of high-quality clinical evidence, and scientific research. The benefits of minimally invasive surgery for common disorders like appendicitis and hypertrophic pyloric stenosis are all supported by good clinical evidence. Although minimally invasive surgery has been extended to neonatal surgery, it is difficult to establish its role for neonatal disorders such as oesophageal atresia and biliary atresia through clinical trials because of the rarity of these disorders. Advances in treatments for biliary atresia and necrotising enterocolitis have been achieved through specialisation, multidisciplinary management, and multicentre collaboration in research; similarly robust clinical evidence for other rare gastrointestinal disorders is needed. As more neonates with gastrointestinal diseases survive into adulthood, their long-term sequelae will also need evidence-based multidisciplinary care. Identifying cures for long-term problems of a complex developmental anomaly such as Hirschsprung's disease will rely on unravelling its pathogenesis through genetics and the development of stem-cell therapy.

Advances in paediatric urology

Paediatric urological surgery is often required for managing congenital and acquired disorders of the genitourinary system. In this Series paper, we highlight advances in the surgical management of six paediatric urological disorders. The management of vesicoureteral reflux is evolving, with advocacy ranging from a less interventional assessment and antimicrobial prophylaxis to surgery including endoscopic injection of a bulking agent and minimally invasive ureteric reimplantation. Evidence supports early orchidopexy to improve fertility and reduce malignancy in boys with undescended testes. A variety of surgical techniques have been developed for hypospadias, with excellent outcomes for distal but not proximal hypospadias. Pelvi-ureteric junction obstruction is mostly detected prenatally; indications for surgery have been refined with evidence, and minimally invasive pyeloplasty is now standard. The outlook for patients with neurogenic bladder has been transformed by a combination of clean intermittent catheterisation, algorithms of diagnostic investigations, and innovative medical and surgical therapies. Posterior urethral valves are associated with considerable mortality; fetal diagnosis allows stratification of candidates for intervention, but ongoing bladder dysfunction in patients after valve ablation remains a cause of long-term morbidity.

Trans-ethnic meta-analysis of genome-wide association studies for Hirschsprung disease

Hirschsprung disease (HSCR) is the most common cause of neonatal intestinal obstruction. It is characterized by the absence of ganglia in the nerve plexuses of the lower gastrointestinal tract. So far, three common disease-susceptibility variants at the RET, SEMA3 and NRG1 loci have been detected through genome-wide association studies (GWAS) in Europeans and Asians to understand its genetic etiologies. Here we present a trans-ethnic meta-analysis of 507 HSCR cases and 1191 controls, combining all published GWAS results on HSCR to fine-map these loci and narrow down the putatively causal variants to 99% credible sets. We also demonstrate that the effects of RET and NRG1 are universal across European and Asian ancestries. In contrast, we detected a European-specific association of a low-frequency variant, rs80227144, in SEMA3 [odds ratio (OR) = 5.2, P = 4.7 × 10-10]. Conditional analyses on the lead SNPs revealed a secondary association signal, corresponding to an Asian-specific, low-frequency missense variant encoding RET p.Asp489Asn (rs9282834, conditional OR = 20.3, conditional P = 4.1 × 10-14). When in trans with the RET intron 1 enhancer risk allele, rs9282834 increases the risk of HSCR from 1.1 to 26.7. Overall, our study provides further insights into the genetic architecture of HSCR and has profound implications for future study designs.

Whole exome sequencing coupled with unbiased functional analysis reveals new Hirschsprung disease genes

Background

Hirschsprung disease (HSCR), which is congenital obstruction of the bowel, results from a failure of enteric nervous system (ENS) progenitors to migrate, proliferate, differentiate, or survive within the distal intestine. Previous studies that have searched for genes underlying HSCR have focused on ENS-related pathways and genes not fitting the current knowledge have thus often been ignored. We identify and validate novel HSCR genes using whole exome sequencing (WES), burden tests, in silico prediction, unbiased in vivo analyses of the mutated genes in zebrafish, and expression analyses in zebrafish, mouse, and human.

Results

We performed de novo mutation (DNM) screening on 24 HSCR trios. We identify 28 DNMs in 21 different genes. Eight of the DNMs we identified occur in RET, the main HSCR gene, and the remaining 20 DNMs reside in genes not reported in the ENS. Knockdown of all 12 genes with missense or loss-of-function DNMs showed that the orthologs of four genes (DENND3, NCLN, NUP98, and TBATA) are indispensable for ENS development in zebrafish, and these results were confirmed by CRISPR knockout. These genes are also expressed in human and mouse gut and/or ENS progenitors. Importantly, the encoded proteins are linked to neuronal processes shared by the central nervous system and the ENS.

Conclusions

Our data open new fields of investigation into HSCR pathology and provide novel insights into the development of the ENS. Moreover, the study demonstrates that functional analyses of genes carrying DNMs are warranted to delineate the full genetic architecture of rare complex diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s13059-017-1174-6) contains supplementary material, which is available to authorized users.

Surgical Intervention for Primary Spontaneous Pneumothorax in Pediatric Population: When and Why?

INTRODUCTION

Spontaneous pneumothorax in pediatric patients is relatively uncommon. The management strategy varies in different centers due to dearth of evidence-based pediatric guidelines. In this study, we reviewed our experience of thoracoscopic management of primary spontaneous pneumothorax (PSP) in children and identified risk factors associated with postoperative air leakage and recurrence.

MATERIALS AND METHODS

We performed a retrospective analysis of pediatric patients who had PSP and underwent surgical management in our institution between April 2008 and March 2015. Demographic data, radiological findings, interventions, and surgical outcomes were analyzed.

RESULTS

A total of 92 patients with 110 thoracoscopic surgery for PSP were identified. The indications for surgery were failed nonoperative management with persistent air leakage in 32.7%, recurrent ipsilateral pneumothorax in 36.4%, first contralateral pneumothorax in 14.5%, bilateral pneumothorax in 10%, and significant hemopneumothorax in 5.5%. Bulla was identified in 101 thoracoscopy (91.8%) with stapled bullectomy performed. 14.5% patients had persistent postoperative air leakage and treated with reinsertion of thoracostomy tube and chemical pleurodesis. 17.3% patients had postoperative recurrence occurred at mean time of 11 months. Operation within 7 days of symptoms onset was associated with less postoperative air leakage (P = .04). Bilateral pneumothorax and those with abnormal radiographic features had significantly more postoperative air leakage (P = .002, P < .01 respectively) and recurrence (P < .01, P = .007).

CONCLUSION

Early thoracoscopic mechanical pleurodesis and stapled bullectomy after thoracostomy tube insertion could be offered as a primary option for management of large PSP in pediatric population, since most of these patients had bulla identified as the culprit of the disease.

Application of anchoring stitch prevents rectal prolapse in laparoscopic assisted anorectal pullthrough

BACKGROUND

Rectal prolapse has been reported after laparoscopic assisted anorectal pullthrough in children with anorectal malformation. We report our clinical outcome and study the application of an anchoring stitch to tack the rectum to the presacral fascia and the occurrence of rectal prolapse.

MATERIAL AND METHODS

A retrospective review of all children who had undergone laparoscopic assisted anorectal pullthrough for anorectal malformation from 2000 to 2015 was performed. Patients were divided into two groups (group I: with anchoring stitch, group II: without anchoring stitch). Outcome measures including rectal prolapse, soiling, voluntary bowel control, and constipation, and Kelly Score were analyzed.

RESULTS

There were thirty-four patients (group I, n=20; group II, n=14) undergoing laparoscopic assisted anorectal pullthrough during the study period. The median follow up duration for group I and group II was 60months and 168months, respectively. All patients had stoma performed prior to the operation. Both groups consisted of patients with high type (30% vs 57%, p=0.12) and intermediate type (70% vs 43%, p=0.12) anorectal malformation. Seven (35%) patients in group I and 3 (21%) in group II had concomitant vertebral and spinal cord pathologies (p=0.408). The mean operative time was significantly shorter in group I (193±63min vs 242±49min, p=0.048). Rectal prolapse occurred less in group I, 4 (20%) vs 9 (64%) patients in group II and was statistically significant (p=0.008). Median time to development of rectal prolapse was 7months in group I and 5months in group II (p=0.767). Mucosectomy was performed in 15% of group I and 36% of group II (p=0.171). Soiling occurred less in group I (55% vs 79%, p=0.167). Voluntary bowel control (85% vs 93%, p=0.499) and constipation (55% vs 64%, p=0.601) were comparable in both groups. 75% in group I and 71% in group II achieved a Kelly score of 5 or above (p=0.823).

CONCLUSIONS

Our study showed application of anchoring stitch reduces rectal prolapse and soiling in laparoscopic assisted anorectal pullthrough. Treatment Study-Level III.

Predictors for bowel resection and the presence of a pathological lead point for operated childhood intussusception: A multi-center study

BACKGROUND

Intussusception may require bowel resection. Here, we aim to define factors that predict the need of bowel resection and the presence of pathological lead point.

METHODS

A retrospective review was taken from three tertiary centers for all operated intussusception patients from January 2010 to December 2014. Patient demographics were recorded. Statistical analysis was performed, and risk factors were derived by binary logistic regression.

RESULTS

Five thousand ninety-six patients were treated for intussusception with 73 (57 male, 16 female) operated. The median age was 23.2months, and median duration of symptoms was 2days. Twenty-eight patients (38.4%) required bowel resection. Logistic regression demonstrated that older age (p=0.018) and longer duration of symptoms (p=0.009) were associated with bowel resection. Furthermore, older age was a predictive factor for the presence of a pathological lead point (p=0.01). A palpable abdominal mass was also found to be associated with the need of bowel resection (risk ratio 2.3) and the presence of pathological lead point (risk ratio 2.3) independently.

CONCLUSION

Older age at presentation and a longer duration of symptoms are positive predictors for the need of bowel resection in intussusception. The presence of a pathological lead point is more likely in older children.

LEVEL OF EVIDENCE

Case series with no comparison group - Level IV.

Beneficial effects of mucous fistula refeeding in necrotizing enterocolitis neonates with enterostomies

BACKGROUND

Necrotizing enterocolitis in premature neonates often results in bowel resection and stoma formation. One way to promote bowel adaptation before stoma closure is to introduce proximal loop effluents into the mucous fistula. In this study, we reviewed our experience with distal loop refeeding with respect to control group.

METHODS

All patients with necrotizing enterocolitis between 2000 and 2014 necessitating initial diverting enterostomies and subsequent stoma closure in a tertiary referral center were included. Medical records were retrospectively reviewed. Demographic data, surgical procedures, and postoperative outcomes were analyzed.

RESULTS

92 patients were identified, with 77 patients receiving mucous fistula refeeding. The refeeding group showed less bowel ends size discrepancy (25 vs 53%, p=0.034) and less postoperative anastomotic leakage (3 vs 20%, p=0.029). Fewer refeeding group patients developed parenteral nutrition related cholestasis (42 vs 73%, p=0.045) and required shorter parenteral nutrition support (47 vs 135days, p=0.002). The mean peak bilirubin level was higher in the non-refeeding group (155 vs 275μmol/L, p<0.001). No major complication was associated with refeeding.

CONCLUSIONS

Mucous fistula refeeding is safe and can decrease risk of anastomotic complication and parental nutrition related cholestasis. It provides both diagnostic and therapeutic value preoperatively and its use should be advocated. Level III Treatment Study in a Case Control Manner.

Laparoscopic versus open operation for perforated peptic ulcer in pediatric patients: A 10-year experience

BACKGROUND

Perforated peptic ulcer (PPU) is a relatively uncommon condition in children. We aim to evaluate and compare the outcomes of laparoscopic omental patch repair versus open repair for PPU in pediatric patients.

METHODS

Children who underwent omental patch repair for PPU from 2004 to 2014 in our hospital were reviewed retrospectively. Patient demographics, perioperative as well as intraoperative details and surgical outcomes, were analyzed.

RESULTS

Thirteen patients were identified, and all presented with abdominal pain. The median age of the study group was 14.9years (range 6.3 to 18.4years). Radiological evidence of pneumoperitoneum on erect chest x-ray (CXR) was found only in five patients (38.5%). None of the patients had a known history of peptic ulcer disease. Diagnosis other than PPU was made in five patients preoperatively. Laparoscopic repair was attempted in eight patients with one of them requiring conversion. There was no significant difference in patient demographics when compared with the open repair group. The perforation site was in the duodenum in 11 patients and in the antrum in two patients. The mean size of perforation was larger in the open repair group (p=0.005). Although the operating time was longer in the laparoscopic group (p=0.51), the length of hospital stay was significantly shorter (p=0.048). Only two patient diseases were Helicobacter pylori related.

CONCLUSION

Clinical features of perforated peptic ulcer in children are different from adults. Risk factors are less frequently identified. Laparoscopic omental patch repair is a feasible surgical option and is associated with satisfactory outcomes in pediatric practice.

Use of robotic-assisted laparoscopic Mitrofanoff appendicovesicostomy in a paediatric patient: problem encountered

This report is of robotic-assisted laparoscopic Mitrofanoff appendicovesicostomy in a 12-year-old patient with detrusor underactivity and hereditary sensory neuropathy. The whole operation was performed in 555 minutes with no open conversion. The patient experienced one episode of stomal stenosis, which required dilatation. At 3-year follow-up, the patient had both stomal and urinary continence. This is a safe and effective procedure to create a means of urinary catheterisation with avoidance of a large unsightly scar and comparable clinical outcome to an open procedure.

Childhood intussusception: 17-year experience at a tertiary referral centre in Hong Kong

OBJECTIVES

To review all paediatric patients with intussusception over the last 17 years.

DESIGN

Retrospective case series.

SETTING

A tertiary centre in Hong Kong.

PATIENTS

Children who presented with intussusception from January 1997 to December 2014 were reviewed.

MAIN OUTCOME MEASURES

The duration of symptoms, successful treatment modalities, complication rate, and length of hospital stay were studied.

RESULTS

A total of 173 children (108 male, 65 female) presented to our hospital with intussusception during the study period. Their median age at presentation was 12.5 months (range, 2 months to 16 years) and the mean duration of symptoms was 2.3 (standard deviation, 1.8) days. Vomiting was the most common symptom (76.3%) followed by abdominal pain (46.2%), per rectal bleeding or red currant jelly stool (40.5%), and a palpable abdominal mass (39.3%). Overall, 160 patients proceeded to pneumatic or hydrostatic reduction, among whom 127 (79.4%) were successful. Three (1.9%) patients had bowel perforation during the procedure. Early recurrence of intussusception occurred in four (3.1%) patients with non-operative reduction. No recurrence was reported in the operative group. The presence of a palpable abdominal mass was a risk factor for operative treatment (relative risk=2.0; 95% confidence interval, 1.8-2.2). Analysis of our results suggested that duration of symptoms did not affect the success rate of non-operative reduction.

CONCLUSIONS

Non-operative reduction has a high success rate and low complication rate, but the presence of a palpable abdominal mass is a risk factor for failure. Operative intervention should not be delayed in those patients who encounter difficult or doubtful non-operative reduction.

Biliary-enteric reconstruction with hepaticoduodenostomy following laparoscopic excision of choledochal cyst is associated with better postoperative outcomes: a single-centre experience

BACKGROUND

With the advent of laparoscopic surgery, more choledochal cysts are excised laparoscopically. In this study, we compared the outcomes from laparoscopic hepaticojejunostomy (HJ) and hepaticoduodenostomy (HD) for biliary-enteric reconstruction.

METHODS

A retrospective analysis of patients who had undergone laparoscopic choledochal cyst excision between February 2005 and January 2014 in a tertiary referral centre was performed. Demographics data, operative techniques and surgical outcomes were analysed according to the way of biliary-enteric reconstruction.

RESULTS

A total of 31 patients were identified, 20 of whom underwent HJ and 11 underwent HD. There were no significant differences in terms of demographics. Median operative time was significantly shorter in HD group (211.0 ± 96.4 vs. 386.0 ± 90.4 min, p = 0.001). Although postoperative enteral feeding was initiated later in HD group (5.0 ± 0.8 vs. 4.0 ± 3.6 days, p = 0.036), postoperative stay in intensive care unit (ICU) (0.7 ± 1.0 vs. 2.4 ± 1.7 days, p = 0.007) and overall hospital stay (9.1 ± 1.0 vs. 14.4 ± 12.2 days, p = 0.157) favoured HD group. There was no perioperative mortality. Median follow-up duration was 24.0 (±11.0) months in HD group and 67.5 (±23.7) months in HJ group. One patient in HJ group had postoperative cholangitis related to anastomotic stricture whereas no cholangitis noted in HD group. In total, five patients in HJ group required second operation for complications and residual diseases whereas none in HD group required reoperation.

CONCLUSIONS

Laparoscopic excision of choledochal cyst with hepaticoduodenostomy reconstruction is safe and feasible with shorter operative time, ICU stay and overall hospital stay. It is not inferior to HJ in terms of short-term postoperative outcomes.

The value of the 24-h delayed abdominal radiograph of barium enema in the diagnosis of Hirschsprung's disease

AIM OF STUDY

The objective of this study is to determine the diagnostic value of the 24-h delayed film for Hirschsprung's disease (HD). Other features of the barium enema were also examined, in particular the correlation between the radiological transition zone (TZ) and the final pathology.

METHODS

All patients with suspected HD from 2003 to 2013 who had undergone barium enema and rectal biopsy were reviewed retrospectively to study the correlation between radiological features of barium enema with the final diagnosis as well as severity.

RESULTS

A total of 182 patients were admitted for suspected HD during the study period, of which 82 had both investigations done. 68 patients had radiological features suggestive of the disease and ultimately, 12 patients had the disease confirmed with rectal biopsy. Among those without radiological features of HD, 2 patients were found to have the disease. Thus, the sensitivity of the 24-h delayed film was 85.7 % and the specificity was 17.6 %. The positive predictive value (PPV) of this test was 20.6 % and the negative predictive value (NPV) was 85.7 %. Regarding the level of TZ, it was not detected in the barium enema in 7 (50 %) out of the 14 patients. For those with the presence of TZ, 6 (85.7 %) of them correlated well with the intra-operative findings and 4 (57.1 %) of them correlated well with the final histology.

CONCLUSION

The 24-h delayed film of barium enema has a high NPV and is useful to rule out HD. However, rectal biopsy is still suggested for disease confirmation given its low PPV. Lastly, once present, the level of radiological TZ is also a useful predictor for the actual disease involvement.

SRY interference of normal regulation of the RET gene suggests a potential role of the Y-chromosome gene in sexual dimorphism in Hirschsprung disease

The Hirschsprung disease (HSCR) is a complex congenital disorder, arising from abnormalities in enteric nervous system (ENS) development. There is a gender disparity among the patients, with the male to female ratio as high as 5 : 1. Loss-of-function mutations of HSCR genes and haploinsufficiency of their gene products are the primary pathogenic mechanisms for disease development. Recent studies identified over half of the HSCR disease susceptibility genes as targets for the sex-determining factor SRY, suggesting that this Y-encoded transcription factor could be involved in sexual dimorphism in HSCR. Among the SRY targets, the tyrosine kinase receptor RET represents the most important disease gene, whose mutations account for half of the familial and up to one-third of the sporadic forms of HSCR. RET is regulated by a distal and a proximal enhancer at its promoter, in which PAX3 and NKX2-1 are the resident transcription factors respectively. We show that the SRY-box 10 (SOX10) co-activator interacts and forms transcriptional complexes with PAX3 and NKX2-1 in a sequence-independent manner and exacerbates their respective transactivation activities on the RET promoter. SRY competitively displaces SOX10 in such transcription complexes and represses their regulatory functions on RET. Hence SRY could be a Y-located negative modifier of RET expression; and if it is ectopically expressed during ENS development, such SRY repression could result in RET protein haploinsufficiency and promotion of HSCR development, thereby contributing to sexual dimorphism in HSCR.

Internationalization: the Hong Kong-China experience as a model for collaborative education in Asia

PURPOSE

The Hong Kong model for collaboration in education in Asia is based on internationalization. Hong Kong benefits from being an international city combining an Eastern heritage and a Western society. The University of Hong Kong ranks among the world's top 25 universities (2012/2013 QS world university rankings), and its Division of Paediatric Surgery has an international reputation in research and training. In the past two decades, Hong Kong has leading roles in major international pediatric surgical organizations including Pacific Association of Pediatric Surgeons, International Pediatric Endosurgery Group, Asian Association of Pediatric Surgeons and World Federation of Associations of Pediatric Surgeons. While Hong Kong has close collaboration with Japan and other advanced economies, the talk will focus on our transfer of international experience to Mainland China.

METHODS AND RESULTS

(1) A Train-the-Trainer scheme consisting of a 1-year structured education program for next-generation leaders from selected centers enabled replication and proliferation of similar training nationwide. (2) A series of laparoscopic workshops resulted in training of over 1,300 surgeons in basic and advanced skills in minimally invasive surgery within 5 years and the establishment of a national specialist organization overseeing development and quality assurance. (3) A series of Cross-Strait Symposia on Pediatric Oncology established the foundation of multidisciplinary, multicenter collaboration in education and research in Mainland China, Taiwan and Hong Kong. (4) Initiation of a scientific writing course will enhance surgical research and training in China.

CONCLUSION

The Hong Kong experience may serve as a model of collaboration with other developing economies in Asia.

Thoracoscopic resection of congenital cystic lung lesions is associated with better post-operative outcomes

INTRODUCTION

The incidence of congenital cystic lung lesions has been increasing in recent years due to better antenatal detection. With the introduction and maturation of thoracoscopy, the operative management for these lesions has seen advancement in the last decade. In this study, we aimed to compare the post-operative outcomes of patients who had thoracoscopic resection with those who underwent open resection.

METHODS

A retrospective review of all patients who underwent surgery for congenital cystic lung lesions between January 1996 and June 2012 in a tertiary referral center was conducted. Patients' demographics, operative procedures and post-operative outcomes were analyzed.

RESULTS

Sixty-seven patients were identified over the past 15 years. Thirty-nine patients had thoracoscopic resections and 28 had open resections. Thirteen patients in the thoracoscopic group required conversion. Both groups had similar demographics in terms of age, body weight and laterality of lesions. The mean operative time and blood loss in the two groups were comparable. Patients in the thoracoscopic group had significantly shorter duration of chest tube drainage (4.3 vs. 6.9 days, p = 0.004), shorter intensive care unit stay (2.5 vs. 5.9 days, p = 0.003) and shorter hospital stay (6.9 vs. 12.0 days, p < 0.001). Post-operative complication rate was similar between the two groups. Patients with body weight less than 5 kg showed a significantly higher conversion to open surgery as compared to those with body weight more than 5 kg (62.5 vs. 25.8 %, p = 0.049).

CONCLUSION

Successful thoracoscopic resection for congenital cystic lung lesions results in better post-operative outcomes. However, this technique remains technically challenging in patients with body weight less than 5 kg.

Thoracoscopic repair of oesophageal atresia: experience of 33 patients from two tertiary referral centres

BACKGROUND

With advances in minimally invasive surgery, thoracoscopic repair of oesophageal atresia has become popular in many centres worldwide and indeed has been described as the pinnacle of neonatal surgery. Here, we report our experience in two tertiary referral centres.

METHODS

Thoracoscopic technique was introduced in 2007. Thus, a retrospective review of all patients diagnosed with oesophageal atresia was carried out. Patients who had thoracoscopic repair were included, and those who had open repair due to co-morbidities were excluded. Patient demographics, operative data, complications, and associated anomalies were noted.

RESULTS

A total of thirty-three patients underwent thoracoscopic repair during the time period. Thirty-one were successfully repaired thoracoscopically. Two patients had conversions due to intra-operative instability. The mean body weight of the neonates was 2.58 kg. The mean operative time was 146 min. Three patients suffered from minor anastomotic leaks, which healed on conservative management. Seven patients had anastomotic strictures, which responded successfully to endoscopic dilatation. Two patients died in the post-operative period due to pneumonia. One patient had a recurrent fistula 3 months after the primary repair, and he subsequently underwent a successful second repair.

CONCLUSIONS

In experienced hands, thoracoscopic repair of oesophageal atresia is at least as good as open surgery but with less surgical trauma. Standard of post-operative care contributes significantly to post-operative outcome. Thoracoscopic technique is now our preferred approach.

Adiponectin mediated MHC class II mismatched cardiac graft rejection in mice is IL-4 dependent

Background

Adiponectin regulates glucose and fatty-acid metabolism but its role in chronic graft rejection mediated by Th2 cytokines remains ill-defined.

Methodology/Principal Findings

Wild type and adiponectin-null mice were used as graft recipients in mouse MHC class II disparate cardiac transplantation (bm12 toB6) and the graft rejection was monitored. In adiponectin-null mice we observed that the cellular infiltrate of eosinophils, CD4⁺ and CD8⁺ T cells was reduced in grafts compared to the controls as was collagen deposition and vessel occlusion. A similar outcome was observed for skin transplants except that neutrophil infiltration was increased. Low levels of IL-4 were detected in the grafts and serum. The effect of adiponectin signaling on IL-4 expression was further investigated. Treatment with AMPK and p38 MAPK inhibitors blocked adiponectin enhanced T cell proliferation in mixed lymphocyte reactions. Inhibition of AMPK reduced eosinophil infiltration in skin grafts in wild type recipients and in contrast AMPK activation increased eosinophils in adiponectin-null recipients. The addition of adiponectin increased IL-4 production by the T cell line EL4 with augmented nuclear GATA-3 and phospho-STAT6 expression which were suppressed by knockdown of adiponectin receptor 1 and 2.

Conclusions

Our results demonstrate a direct effect of adiponectin on IL-4 expression which contributes to Th2 cytokine mediated rejection in mouse MHC class II histoincompatible transplants. These results add to our understanding of the interrelationship of metabolism and immune regulation and raise the possibility that AMPK inhibitors may be beneficial in selected types of rejection.

Peanut aspiration: an avoidable life-threatening condition

Foreign body aspiration is a potentially fatal condition. Yet, an accurate diagnosis may not be easy. Management is also challenging and requires a high level of expertise with proper instruments. In this article, we report our experience in the management of peanut aspiration in two young children by means of a ventilating bronchoscope.

Bile duct anastomotic stricture after pediatric living donor liver transplantation

BACKGROUND/PURPOSE

Hepaticojejunostomy is a well-accepted method, whereas duct-to-duct anastomosis is gaining popularity for bile duct reconstruction in pediatric living donor liver transplantation (LDLT). Biliary complications, especially biliary anastomotic stricture (BAS), are not clearly defined. The aim of the present study is to determine the rate of BAS and its associated risk factors.

METHODS

The study included 78 pediatric patients (<18 years old) who underwent LDLT during the period from end of September 1993 to end of November 2010. The diagnosis of BAS was based on clinical, biochemical, histologic, and radiologic results.

RESULTS

All patients received left-side grafts. Thirteen patients (16.7%) developed BAS after LDLT. Among them, 3 patients (23.1%) had duct-to-duct anastomosis during LDLT. The median follow-up period for the BAS group and the non-BAS group was 57.8 and 79.5 months, respectively (P = .683). Ten of the patients with BAS required percutaneous transhepatic biliary drainage with or without dilatation for treating the stricture. Multivariable analysis showed that hepatic artery thrombosis and duct-to-duct anastomosis were 2 risk factors associated with BAS.

CONCLUSION

In pediatric LDLT, hepaticojejunostomy is the preferred method for bile duct reconstruction, but more large-scale research needs to be done to reconfirm this result.

Early post-operative interleukin-6 and tumor necrosis factor-α levels after single-port laparoscopic varicocelectomy in children

PURPOSE

Laparoendoscopic single-site surgery has recently been described in children and regarded as an improved technology leading to less pain and better cosmetic outcome. Compared to the traditional three-port method, it is not known if the single-port method is less invasive. The aim of this study was thus to investigate the post-operative acute inflammatory response in order to evaluate surgical stress in the two surgical approaches in children.

METHODS

A prospective, single blinded, case-control study was carried out. Thirteen male patients who presented with unilateral varicocele were divided into two groups. Six children underwent single-port laparoscopic procedure, while the other seven children underwent three-port laparoscopic procedure. Pre-operative and post-operative blood samples were taken for the measurement of tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) using ELISA. Demographics including the operation time, and complications were recorded. Data between the two groups were analyzed using unpaired t-test and a p value of <0.05 was taken as statistically significant.

RESULTS

The mean age of patients was 14.5 years (range 12-19 years). There was no significant difference between the two groups in terms of operative time, nor there was any complication recorded. The change in serum TNF-α and IL-6 concentrations pre- and post-operatively between the single-port group and three-port group was not statistically significant. Overall, patients in the two groups showed excellent satisfaction in terms of post-operative cosmesis.

CONCLUSION

Single-port laparoscopic varicocelectomy is safe, effective and produces excellent cosmesis with minimal surgical stress.

Upregulation of UCP2 by adiponectin: the involvement of mitochondrial superoxide and hnRNP K

BACKGROUND

The adipocyte-derived hormone adiponectin elicits protective functions against fatty liver diseases and hepatic injuries at least in part by stimulating the expression of a mitochondrial inner membrane transporter, uncoupling protein 2 (UCP2). The present study was designed to investigate the cellular and molecular mechanisms underlying adiponectin-induced UCP2 expression.

METHODOLOGY/PRINCIPAL FINDINGS

Mice were treated with adiponectin and/or different drug inhibitors. Parenchymal (PCs) and nonparenchymal (NPCs) cells were fractionated from the liver tissues for mitochondria isolation, Western blotting and quantitative PCR analysis. Mitochondrial superoxide production was monitored by MitoSOX staining and flow cytometry analysis. Compared to control mice, the expression of UCP2 was significantly lower in NPCs, but not PCs of adiponectin knockout mice (AKO). Both chronic and acute treatment with adiponectin selectively increased the mRNA and protein abundance of UCP2 in NPCs, especially in the enriched endothelial cell fractions. The transcription inhibitor actinomycin D could not block adiponectin-induced UCP2 expression, whereas the protein synthesis inhibitor cycloheximide inhibited the elevation of UCP2 protein but not its mRNA levels. Mitochondrial content of heterogeneous nuclear ribonucleoprotein K (hnRNP K), a nucleic acid binding protein involved in regulating mRNA transportation and stabilization, was significantly enhanced by adiponectin, which also evoked a transient elevation of mitochondrial superoxide. Rotenone, an inhibitor of mitochondrial respiratory complex I, abolished adiponectin-induced superoxide production, hnRNP K recruitment and UCP2 expression.

CONCLUSIONS/SIGNIFICANCE

Mitochondrial superoxide production stimulated by adiponectin serves as a trigger to initiate the translocation of hnRNP K, which in turn promotes UCP2 expressions in liver.

Evaluation of defecative function 5 years or longer after laparoscopic-assisted pull-through for imperforate anus

BACKGROUND

Laparoscopic anorectoplasty was introduced in 2000, but the procedure has not yet gained universal acceptance. Previous studies, including ours, reported satisfactory early postoperative outcome as compared with posterior sagittal anorectoplasty (PSARP), but mid- to long-term results are not available. Here, we aim to evaluate the mid- to long-term defecative function in these patients.

MATERIALS AND METHODS

A retrospective study was carried out and included all patients who underwent laparoscopic-assisted anorectoplasty for high-/intermediate-type imperforate anus between 2001 and 2005. Their degree of continence was graded according to the Krickenbeck classification and compared with historical controls treated with PSARP. The results were compared using χ(2) test, and P < .05 was considered statistically significant.

RESULTS

There were 18 patients who underwent laparoscopic anorectoplasty (LAR) in the study period. They were compared with 20 historical PSARP patients. For defecation sensation, 16 of the 18 LAR patients were positive, whereas there were 16 of 20 PSARP patients. Eight LAR patients were clean without any fecal soiling or incontinence (11/20 PSARP). Only 3 of 18 LAR had constipation as compared with 7 of 20 PSARP. The need for rectal enema for evacuation was seen in 1 of 20 LAR patients and 2 of 20 PSARP patients (for all categories, P > .05).

CONCLUSIONS

Mid- to long-term follow-up study revealed satisfactory defecative function for patients with high-/intermediate-type imperforate anus after LAR. The outcome is at least as good as PSARP. Longer term follow-up with larger sample size is necessary to demonstrate the benefits of LAR over PSARP.

Functional analyses of RET mutations in Chinese Hirschsprung disease patients

BACKGROUND

Hirschsprung disease (HSCR) is a congenital disease characterized by the absence of ganglion cells in various length of distal digestive tract. The rearranged during transfection gene (RET) is considered the major gene in HSCR. Although an increasing number of HSCR-associated RET coding sequence (CDS) mutations have been identified in recent years, not many have been investigated for functional consequence on the RET protein.

METHODS AND RESULTS

We examined the functional implications of the de novo RET-CDS mutations V145G, Y483X, V636fsX1, and F961L that we first identified in sporadic Chinese patients with HSCR. The V145G disrupted RET glycosylation and F961L RET phosphorylation. Presumably, the truncation mutations would affect the translocation or the anchoring of the RET protein onto the cellular membrane.

CONCLUSION

The study of RET-CDS mutations that appear de novo is essential not only for understanding the mechanistic of the disease but also for penetrance and recurrence risk estimations, being the ultimate goal for the improvement in disease management and counseling.

The potency of allospecific Tregs cells appears to correlate with T cell receptor functional avidity

CD4(+) CD25(+) regulatory T cells (T(reg) cells) are an attractive adoptive cell therapy in mediating transplantation tolerance. T-cell receptor (TcR) activation is critical for T(reg) function, suggesting that the TcR avidity of T(reg) cells used in therapy may affect the therapeutic outcome. To address this, we compared the regulatory capacity of T(reg) lines expressing TcRs derived from two TcR transgenic mice shown to have the same specificity but different functional avidities. T(reg) lines generated from CD4(+)CD25(+) T cells from C57BL/6 mice were transduced with one of either of these TcRs. The antigen specificity of the transduced T(reg) lines was confirmed in vitro. T(reg) lines expressing the TcR with higher functional avidity showed stronger suppressive capacity in a linked suppression model in vitro. Furthermore, the same T(reg) lines demonstrated a stronger proliferation in vivo following antigen exposure. Pretreatment of recipient BL/6 mice with these T(reg) cells, together with anti-CD8 antibody and Rapamycin therapies, prolonged survival of BALB/c skins, as compared with mice that received T(reg) lines with lower TcR avidity. Taken together, these data suggest that the TcR functional avidity may be important for T(reg) function. It highlights the fact that strategies to select T(reg) with higher functional avidity might be beneficial for immunotherapy in transplantation.