Type 1 IFN Induction by Cytosolic Nucleic Acid Is Intact in Neonatal Mononuclear Cells, Contrasting Starkly with Neonatal Hyporesponsiveness to TLR Ligation Due to Independence from Endosome-Mediated IRF3 Activation.

Two million infants die each year from infectious diseases before they reach 12 mo; many of these diseases are vaccine preventable in older populations. Pattern recognition receptors represent the critical front-line defense against pathogens. Evidence suggests that the innate immune system does not fully develop until puberty, contributing to impaired response to infection and impaired vaccine responses in neonates, infants, and children. The activity of the pattern recognition receptor family of cytosolic nucleic acid (CNA) sensors in this pediatric population has not been reported. We show that in direct contrast to weak TLR-induced type I IFN in human cord blood mononuclear cells, cord blood mononuclear cells are capable of initiating a potent response to CNA, inducing both antiviral type I IFN and, unexpectedly, proinflammatory TNF-α. A deficiency in Rab11-GTPase endosome formation and consequent lack of IRF3 activation in neonatal monocytes is at least in part responsible for the marked disparity in TLR-induced IFN production between neonatal and adult monocytes. CNA receptors do not rely on endosome formation, and therefore, these responses remain intact in neonates. Heightened neonatal responses to CNA challenge are maintained in children up to 2 y of age and, in marked contrast to TLR4/9 agonists, result in IL-12p70 and IFN-γ generation. CNA sensors induce robust antiviral and proinflammatory pathways in neonates and children and possess great potential for use as immunostimulants or vaccine adjuvants for targeted neonatal and pediatric populations to promote cell-mediated immunity against invasive infectious disease.

Nucleic acid cytokine responses in obese children and infants of obese mothers.

Almost a third of Irish children are now overweight and the country ranks 58th out of 200 countries for its proportion of overweight youths. With the rising obesity epidemic, and the impaired immune responses of this population, it is vital to understand the effects that obesity has on the immune system and to design future therapeutics, adjuvants and vaccines with overweight and obese populations in mind. Many current vaccines use adjuvants that have been found to be less effective at stimulating the immune response in children compared with adults and there is now substantial effort to design paediatric-focused adjuvants. Additionally, vaccine responses have been shown to be less effective in obese populations indicating that this is a particularly vulnerable population. We have recently identified cytosolic nucleic acids (CNAs), as novel candidate adjuvants for childhood vaccines. Here we investigated whether immune responses to these candidate adjuvants were adversely affected in infants born to overweight or obese mothers, and in overweight and obese children. Type I Interferon (IFN) and proinflammatory cytokines such as Tumor Necrosis Factor α (TNFα) are vital for driving innate and adaptive immune responses. We found that childhood obesity conferred no significant adverse effect on CNA-induced Type I IFN responses when compared with lean children. Similarly, Type I IFN responses were intact in the cord blood of babies delivered from overweight and obese mothers, when compared with lean mothers. There was also no significant impact of obesity on CNA-induced TNFα responses in children or from cord blood of infants born to overweight/obese mothers. In all cases, there was a tendency towards decreased production of innate cytokine Type I Interferon and TNFα, however there was no significant negative correlation. Interestingly, high maternal BMI showed weak and moderate positive correlation with IL-12p70 and IFNγ, respectively, in response to CNA stimulation. This study demonstrates that future adjuvants can be tailored for these populations through the use of activators of CNA sensors.

Notochord manipulation does not impact oesophageal and tracheal formation from isolated foregut in 3D explant culture.

BACKGROUND: Tracheo-oesophageal malformations result from disturbed foregut separation during early development. The notochord, a specialised embryonic structure, forms immediately adjacent to the dividing foregut. In the Adriamycin mouse model of oesophageal atresia, foregut and notochord abnormalities co-exist, and the site and severity of foregut malformations closely correlate to the position and extent of the notochord defects. Notochord and foregut abnormalities also co-exist in the Noggin Knockout mouse as well in a small number of human cases. The notochord is a source of powerful molecular signals during early embryogenesis, being particularly important for neural crest development. The influence of notochord signaling on the adjacent foregut is not known. The purpose of this study was to examine the impact of notochord manipulation on foregut separation using a robust 3D explant method for culturing isolated foregut which permits oeosphageal and tracheal formation in vitro. METHODS: Foregut was micro-dissected from embryonic day 9 mice (License B100/4447 Irish Medicines Board), embedded in collagen and cultured for 48 h with native notochord intact (n = 6), notochord removed (n = 10) or additional notochord transplanted from stage matched controls (n = 8). Specimens were analysed for foregut morphology and molecular patterning using immunohistochemistry for Hnf3b (an endoderm marker) and Sox2 (a notochord and oesophageal marker) on cryosections. RESULTS: Foregut separation into distinct oesophagus and trachea was observed in isolated foregut specimens with or without their native notochord. In specimens with additional notochord transplants, foregut morphology and molecular patterning were comparable to controls whether or not the native notochord was maintained. In particular foregut separation was not disrupted by the transplantation of additional notochord at the dorsal foregut endoderm. CONCLUSION: The relationship between the embryonic foregut and notochord is complex and ill-defined; however, the notochord does not contribute essentially to oesophagus and trachea formation beyond E9 in the mouse, and the transplantation of additional notochord does not disrupt foregut separation in 3D explant culture.

Abdominal radiography is not necessary in children with intussusception.

BACKGROUND: Children with intussusception require rapid and accurate diagnosis to enable timely intervention for satisfactory outcome. Ultrasonography is the recommended standard diagnostic modality; however, abdominal radiography (AR) is still used as an initial investigation. The aim of this study was to investigate the benefit of AR in intussusception by determining diagnostic accuracy and analysing correlation of AR findings with outcome. METHODS: Index cases of intussusception presenting over 15 years (1998-2013) were analysed. Those who had AR performed were allocated into groups with positive or normal findings. Outcome of pneumatic reduction of intussusception (PRI) between these groups was compared. RESULTS: Six hundred and forty-four cases of intussusception treated with PRI were identified, 412 (64 %) had AR performed and 232 (36 %) did not. 303 (74 %) radiographs had positive findings and 109 (26 %) were normal. The success rate of PRI did not differ between AR positive (82 %) and AR normal (84 %). Occult pneumoperitoneum was not detected in any patient by AR in our cohort. CONCLUSION: AR is not recommended for the diagnosis of intussusception in children, for the prediction of the outcome of PRI or for the detection of occult pneumoperitoneum. AR should always be performed when clinical peritonism is present but is not otherwise necessary in children with suspected or confirmed intussusception.

Familial Hirschsprung's disease: a systematic review.

INTRODUCTION: Hirschsprung's disease (HSCR) is a multi-genetic disorder with complex inheritance patterns. Population risk is 1 in 5000 but is reported to be increased in families of patients with HSCR. Appropriate counseling of affected families could be assisted by data from a large volume of patients. It was the aim of this study to systematically analyse the patterns of familial HSCR in the published literature. METHODS: Pubmed (®) database was searched using the terms "Hirschsprung's disease" and "familial" for studies published between 1980 and 2015 on cohorts of index patients with HSCR reporting on familial recurrence. Studies giving rates of familial HSCR together with the total number of HSCR cases at that centre were included. RESULTS: In 4331 index cases of HSCR, an overall rate of 7.6% familial recurrence was found. In total colonic aganglionosis, 20% of cases were familial. Recurrence of HSCR within families predominantly occurred in siblings (62%) and was reported between parent and offspring in 22% and in other relatives in 16%. Multiple generations were affected in 15% of families. CONCLUSION: Familial recurrence of HSCR occurs frequently and should be discussed with families of diagnosed patients. Genetic counseling should be offered in these families and in particular for those patients with long segment and total colonic aganglionosis.

Altered Tbx1 gene expression is associated with abnormal oesophageal development in the adriamycin mouse model of oesophageal atresia/tracheo-oesophageal fistula.

INTRODUCTION: Oesophageal atresia/tracheo-oesophageal atresia (OA/TOF) frequently arises with associated anomalies and has been clinically linked with 22q11 deletion syndromes, a group of conditions due to Tbx1 gene mutation which include Di George syndrome. Tbx1 and Tbx2 genes modulate pharyngeal and cardiac development, but are also expressed in the developing foregut and are known to interact with key signalling pathways described in oesophageal formation including bone morphogenic proteins. The adriamycin mouse model (AMM) reliably displays OA/TOF-like foregut malformations providing a powerful system for investigating the disturbances in gene regulation and morphology involved in tracheo-oesophageal malformations. We hypothesised that foregut abnormalities observed in the AMM are associated with altered Tbx1 and Tbx2 gene expression. METHODS: Time-mated CBA/Ca mice received intra-peritoneal injection of adriamycin (for treated) or saline (for controls) on embryonic days (E)7 and 8. Untreated Cd1 embryos were used to establish normal expression patterns. Embryos harvested on E9-E11 underwent whole-mount in situ hybridization with labelled RNA probes for Tbx1 and Tbx2. Optical projection tomography was used to visualise expression in whole embryos by 3D imaging. RESULTS: Tbx1 expression was visualised in a highly specific pattern in the proximal oesophageal endoderm in normal and control embryos. In the AMM, extensive ectopic expression of Tbx1 was detected in the dorsal foregut and adjacent to the TOF. The focally restricted oesophageal expression pattern persisted in the AMM, but was posteriorly displaced in relation to the tracheal bifurcation. Tbx2 was widely expressed in the ventral foregut mesoderm of controls, lacking specific endoderm localisation. In the AMM, altered Tbx2 expression in the foregut was only seen in severely affected embryos. CONCLUSION: Highly specific Tbx1 expression in the proximal oesophageal endoderm suggests that Tbx1 may be an important regulator of normal oesophageal development. Altered Tbx1 expression in dorsal foregut and adjacent to the TOF in the AMM suggests that Tbx1 gene disruption may contribute to the pathogenesis of tracheo-oesophageal malformations.

Familial megacystis microcolon intestinal hypoperistalsis syndrome: a systematic review.

BACKGROUND: Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is a rare and severe disorder of functional obstruction affecting bladder and bowel, usually diagnosed in the neonatal period. Over 230 cases have been reported since Berdon and colleagues first described this clinical entity in 1976. The exact pathogenesis of MMIHS is unknown. Familial occurrence of MMIHS has been reported and could offer insight into the aetiology of this disease. The purpose of this study was to systematically review the published literature for the evidence of familial MMIHS and to characterise these presentations. METHODS: A literature search was performed using the keywords "megacystis microcolon intestinal hypoperistalsis" (1976-2013). Retrieved articles, including additional studies from reference lists, were reviewed for consanguinity between parents and recurrence of MMIHS between siblings. Data were extracted for cases where familial MMIHS was present. RESULTS: A total of 47 patients were reported in which familial MMIHS was likely or confirmed. 15 sibling sets were definitively diagnosed with MMIHS (14 pairs and one set of three siblings). Four further index patients with a confirmed diagnosis and also one of the sibling pairs were reported to have a sibling in which MMIHS was probable. Consanguinity between parents was present in four of the confirmed sibling sets and in an additional seven individual cases. The outcome for familial MMIHS is generally poor. Multiple sibling fatalities were frequent and in only one family were both siblings' survivors at the time of reporting. CONCLUSION: Consanguinity between parents and recurrence in siblings indicate that MMIHS is inherited in an autosomal recessive manner. With the advent of next generation sequencing, these familial clusters may be key to determining the genetic basis for MMIHS.

Does the length of the history influence the outcome of pneumatic reduction of intussusception in children?

PURPOSE: Intussusception is the most common cause of acute abdomen in infants and preschool children. Nonoperative reduction using air enema is an established treatment in children with intussusception. The aim of this study was to determine whether length of the history influences the outcome of pneumatic reduction of intussusception in children? METHODS: The medical records of 256 consecutive children with intussusception between July 1998 and June 2010, who underwent air enema reduction regardless of the length of the history were reviewed. In all 256 patients, intussusception was confirmed by ultrasound before proceeding to air enema. RESULTS: The length of history ranged from 2 to 240 h with median time of 18.5 h. The median age in 256 patients was 7 months (range 1 day to 12 years). The presenting clinical features included irritability/abdominal pain (77%), vomiting (80%), bleeding per rectum (36%) and palpable abdominal mass (50%). Air enema reduction was successful in 234 (91.5%) of the 256 patients. In 22 (8.5%) patients, air enema failed to reduce the intussusception and 3 (1.1%) of these patients had colonic perforation during the procedure. All 22 patients required surgery. The duration of symptoms did not influence the outcome of pneumatic reduction. 37 (14%) patients developed recurrence after successful pneumatic reduction of intussusception, with 58% presenting within 48 h of the initial procedure. CONCLUSION: Our data suggest that pneumatic reduction should be first-line treatment in all children with intussusception regardless of the length of the history.

Rare Association of Extended Total Colonic Aganglionosis and Intestinal Malrotation.

Total colonic aganglionosis occurring together with malrotation is a rare occurrence and may pose diagnostic and management dilemmas for the paediatric surgeon. We report a case of a neonate that presented with extended total colonic aganglionosis and malrotation, along with a spectrum of central nervous system and renal abnormalities. The clinical and radiological features and potential diagnostic and management pitfalls are discussed along with a literature review of this exceptionally infrequent association.