Neural crest-derived defects in experimental esophageal atresia

Tracheo-Esophageal Fistula (TEF) in a Newborn Following Maternal Antenatal Exposure to Olanzapine

There is a dearth of evidence on the safety of the use of antipsychotics during pregnancy. Olanzapine, a pregnancy category C drug, has no unequivocal evidence of harm to the fetus. Against this backdrop, we report the first case of a tracheo-esophageal fistula (TEF) in a newborn following maternal antenatal exposure to olanzapine. A 29-year-old woman with acute psychotic disorder had been treated with olanzapine for the last 7 years. Her first pregnancy, while taking olanzapine, resulted in a miscarriage at 4 months' gestation, following which she discontinued olanzapine. She reconceived after a few months and delivered a full-term normal child. However, due to the recurrence of psychiatric illness after her second pregnancy, she was prescribed olanzapine again, which was continued throughout her third pregnancy. The outcome of the third pregnancy was a full-term female baby with a TEF. The baby was managed surgically and discharged with satisfactory vital signs. Unfortunately, however, the baby did not survive beyond 11 months of age. Causality between antenatal maternal olanzapine exposure and TEF in the newborn was determined to be 'probable' (score +5) as per the Naranjo causality assessment scale. Greater knowledge of this potential teratogenicity caused by olanzapine is needed to reduce morbidity and mortality in newborns.

Vascular Anomalies Associated with Esophageal Atresia and Tracheoesophageal Fistula

OBJECTIVE

To report the incidence of congenital vascular anomalies in a cohort of patients with esophageal atresia (EA) and tracheoesophageal fistula (TEF) while describing the clinical presentation, diagnosis, and consequences, and to evaluate the diagnostic value of esophagram in diagnosing an aberrant right subclavian artery (ARSA).

METHODS

All patients born with EA/TEF between 2005 and 2013 were studied. Preoperative echocardiography reports, surgical descriptions of primary esophageal repair, and esophagrams were reviewed retrospectively.

RESULTS

Of the 76 children born with EA/TEF included in this study, 14 (18%) had a vascular malformation. The incidence of a right aortic arch (RAA) was 6% (5 of 76), and that of an aberrant right subclavian artery (ARSA) was 12% (9 of 76). RAA was diagnosed in the neonatal period by echocardiography (4 of 5) or surgery (1 of 5), and ARSA was diagnosed by echocardiography (7 of 9) or later on the esophagram (2 of 9). Respiratory and/or digestive symptoms occurred in 9 of the 14 patients with vascular malformation. Both long-gap EA and severe cardiac malformations necessitating surgery were significantly associated with vascular anomalies (P<.05). The sensitivity of the esophagram for diagnosing ARSA was 66%, the specificity was 98%, the negative predictive value was 95%, and the positive predictive value was 85%.

CONCLUSION

ARSA and RAA have an incidence of 12% and 6% respectively, in patients with EA/TEF. A computed tomography angioscan is recommended to rule out such malformations when stenting of the esophagus is indicated, before esophageal replacement surgery, and when prolonged (>2 weeks) use of a nasogastric tube is considered.

Lung hypoplasia in rats with esophageal atresia and tracheo-esophageal fistula

INTRODUCTION

Survivors of esophageal atresia and tracheo-esophageal fistula (EA-TEF) often suffer chronic respiratory tract disease. EA-TEF results from abnormal emergence of the trachea from the foregut. This study in a rat model tests the hypothesis that primary lung maldevelopment might be a downstream consequence of this defect.

RESULTS

The lung was hypoplastic in rats with EA-TEF although the histological pattern was normal. Maturation and arteriolar wall thickness were unchanged, but mesenchymal control of airway branching was weakened. This branching was deficient from embryonal day (E13) on in adriamycin-treated explants.

DISCUSSION

In conclusion, the lungs were hypoplastic in rats with experimental EA-TEF due to defective embryonal airway branching. However, arteriolar wall and respiratory epithelial patterns remained normal. These findings suggest that similarly defective lung development might contribute to chronic respiratory disease in EA-TEF patients.

METHODS

Pregnant rats received either 1.75 mg/kg i.p. adriamycin or vehicle on E7, E8, and E9. Lungs were recovered at E15, E18, and E2. Lung weight/body weight ratio, total DNA and protein, radial alveolar count, arteriolar wall thickness, lung maturity, and mesenchymal control of airway branching were assessed. E13 lungs were cultured for 72 h and explant airway branching was measured daily. For comparisons, nonparametric tests (*P < 0.05) were used.

Congenital anomalies of the esophagus

Congenital malformations of the esophagus are frequently encountered by pediatric surgeons, especially esophageal atresia with or without tracheo-esophageal fistula. However, the molecular mechanisms underlying the development of these various anomalies are not clear. Here we present a brief overview of the embryologic development of the tracheoesophageal tube, along with some of the genetic controls which, when defective can lead to abnormal separation of this tube.

Stephen L. Gans Distinguished Overseas Lecture. The neural crest in pediatric surgery

AIM

This review highlights the relevance of the neural crest (NC) as a developmental control mechanism involved in several pediatric surgical conditions and the investigative interest of following some of its known signaling pathways.

METHODS

The participation of the NC in facial clefts, ear defects, branchial fistulae and cysts, heart outflow tract and aortic arch anomalies, pigmentary disorders, abnormal enteric innervation, neural tumors, hemangiomas, and vascular anomalies is briefly reviewed. Then, the literature on clinical and experimental esophageal atresia-tracheoesophageal fistula (EA-TEF) and congenital diaphragmatic hernia (CDH) is reviewed for the presence of associated NC defects. Finally, some of the molecular signaling pathways involved in both conditions (sonic hedgehog, Hox genes, and retinoids) are summarized.

RESULTS

The association of facial, cardiovascular, thymic, parathyroid, and C-cell defects together with anomalies of extrinsic and intrinsic esophageal innervation in babies and/or animals with both EA-TEF and CDH strongly supports the hypothesis that NC is involved in the pathogenesis of these malformative clusters. On the other hand, both EA-TEF and CDH are observed in mice mutant for genes involved in the previously mentioned signaling pathways.

CONCLUSIONS

The investigation of NC-related molecular pathogenic pathways involved in malformative associations like EA-TEF and CDH that are induced by chromosomal anomalies, chemical teratogens, and engineered mutations is a promising way of clarifying why and how some pediatric surgical conditions occur. Pediatric surgeons should be actively involved in these investigations.

Expression of homeotic genes Hoxa3, Hoxb3, Hoxd3 and Hoxc4 is decreased in the lungs but not in the hearts of adriamycin-exposed mice

Exposure of rat and mouse embryos to adriamycin (doxorubicin chlorhydrate) induces esophageal atresia (EA) and VACTERL association. Sonic hedgehog (Shh) and Gli2/Gli3 pathways are involved in these conditions and knockout mice for homeotic Hox genes Hoxa3, Hoxb3, Hoxc3, Hoxc4 and Hoxa5 show phenotypes with some of the associated VACTERL features. This study aims at evaluating the possible influence of Hoxa3, Hoxb3, Hoxd3 and Hoxc4 as upstream regulators of this complex signalling. Pregnant mice were exposed either to 4 mg/kg of adriamycin (EA group) or vehicle (controls) on embryonic days 7.5 and 8.5. Embryos were recovered at four endpoints (E12.5-E15.5) and randomly assigned for immunohistochemical or molecular biology studies. Lungs and hearts were separately harvested and processed for Hoxa3, Hoxb3, Hoxd3 and Hoxc4 quantitative RT-PCR measurements. Antibodies for Hoxa3, Hoxb3 and Hoxd3 proteins were used for immunohistochemical studies. RT-PCR studies showed a drastic and statistically significant decrease of the four genes in the lungs of EA mice when compared to controls, with a slight recovery from E15.5. Hearts of both groups showed a similar expression of all the genes throughout gestation. Control embryos expressed the hox3 paralogous genes in heart, skin, foregut derivatives and their surrounding mesoderm through E12.5-E15.5 whereas adriamycin-exposed embryos showed a severe decrease in expression of these three proteins in the same tissues but not in the heart. Adriamycin drastically reduced the expression of Hoxa3, Hoxb3, Hoxd3 and Hoxc4 in mice embryonic lungs. Their expression in the heart did not seem to be influenced by adriamycin in this experimental setting.

Pediatric epilepsy evaluations from the prenatal perspective

Prenatal contributions to childhood epilepsy include malformations and acquired injuries, which can occur from conception and throughout gestation. Five case histories from the Pediatric Epilepsy Service are discussed that exemplify maternal, fetal, and placental conditions that contribute to childhood epilepsy. Two full-term neonates presented with neonatal seizures, with or without accompanying encephalopathy. Placental pathology suggested antepartum maternal-placental diseases that caused or contributed to their brain disorders. Two children presented as preterm infants with systemic organ system diseases that also implicated brain injury. One child had a complicated maternal history with both genetic and acquired illnesses. Two children required epilepsy surgery, with improved seizure control despite persistent neurocognitive and neurobehavioral deficits related to diffuse encephalopathies. Dual pathology should include prenatal contributions to childhood epilepsy on both a genetic and acquired basis. Epileptologists should consider an ontogenetic approach to study the epileptic condition from a fetal neurology perspective.

Impact of preoperative diagnosis of congenital heart disease on the treatment of esophageal atresia

Congenital heart disease (CHD) has a major impact on the survival of babies with esophageal atresia (EA). The present study assesses whether early diagnosis influences the management strategies in a large series of EA. Cases of EA treated between 1982 and 2002 were retrospectively divided into groups according to the presence or absence of CHD and to whether this was diagnosed or not prior to tracheo-esophageal fistula repair. Patients were also staged according to Spitz's classification in which major congenital heart disease (MCHD) are those associated with cyanosis and/or heart failure requiring surgery. Comparisons between groups of patients were made by standard statistical tests. Among 195 babies with EA (99 boys and 96 girls), 82 (42%) had CHD (31 boys, 39% and 51 girls, 61%, chi2 P < 0.05) and 43 out of these 82 (52%) had MCHD. Six children died without treatment. CHD was diagnosed prenatally in six cases and before EA repair in 26 cases. The diagnoses were missed in 12 instances (in five it was a MCHD). Regardless of preoperative diagnosis of right aortic arch in 3/6 cases, the oesophagus was approached from the right thorax in all cases and only in one of them the operation was not completed due to hemodynamic instability. There were 145/195 (75%) Spitz group I patients; 44/195 (22%) were group II and 6/195 (3%) group III. The mortality was respectively 9.5, 59 and 83%. We lost 15/113 (13%) babies with EA without CHD, 4/39 (10.2%) with EA and CHD and 26/43 (60%) with EA and MCHD. In children with CHD diagnosed prior to the esophageal operation 8/26 (30.7%) died and among those without diagnoses 3/12 (25%) died, (chi2 P > 0.1). 1. CHD was diagnosed after EA repair in one-third of cases. 2. Preoperative diagnosis of CHD changed the operative indication only in one case. 3. Survival after treatment for EA was not influenced by the moment or the accuracy of the diagnosis of CHD in this series. 4. With only a few exceptions, associated CHD should not change the strategies of EA repair.

Decrease of parafollicular thyroid C-cells in experimental esophageal atresia: further evidence of a neural crest pathogenic pathway

Adriamycin-induced experimental esophageal atresia (EA) is often associated with malformations of neural crest (NC) origin, such as abnormal pharyngeal pouch derivatives like the thymus and the parathyroids. The aim of the present study was to examine whether NC-derived thyroid C-cells were abnormal in a rat model. Pregnant rats received intraperitoneally either 2 mg/kg Adriamycin (EA) or vehicle (controls) on days 8 and 9 of gestation. Fetuses were recovered on day 21, and blocks including the trachea and thyroid were fixed in formalin, coronally sectioned at 3-mum widths, and stained with standard hematoxylin and eosin until the largest area of thyroid was reached. From this point on, the 1st, 10th, and 20th slices were immunohistochemically stained with anti-calcitonin antibody. Positively-stained cells in each section of the gland were counted using a computer-assisted image analysis method, and the results were averaged. The distribution of the cells within the gland was assessed as well. Comparisons between EA and control rats were made by nonparametric tests with a significance threshold of p<0.05. The number of C-cells was dramatically reduced in EA animals compared with controls (32.4+/-36 vs. 92.3+/-60.5, p<0.001). Histology of the thyroid was similar in both groups, but the distribution of positive C-cells within the gland followed an abnormal pattern in EA rats. Adriamycin causes a pattern of NC-derived malformations, including a severe decrease in thyroid C-cells accompanied by abnormal distribution or migration patterns. These results represent further evidence of the involvement of NC organogenic control dysregulation in the pathogenesis of EA and its associated malformations. The similarities between the rat model and the clinical picture strongly support investigating other subclinical NC-derived anomalies in patients with EA.

Pattern of cardiovascular anomalies associated with esophageal atresia: support for a caudal pharyngeal arch neurocristopathy

Patients with cephalic neurocristopathy (an abnormality of neural crest differentiation) present a striking pattern of associated cardiovascular anomalies (CVA). Therefore, to support the hypothesis that esophageal atresia (EA) may be related to a defective contribution from the cephalic neural crest, we studied the pattern of CVA associated with EA. Medical records of 99 patients with isolated EA, 101 with isolated anorectal malformations (ARM) and 15 with both EA and ARM, consecutively admitted to our unit, were reviewed. The prevalence and pattern of CVA associated with isolated EA or isolated ARM were compared on the assumption that the cranial or caudal location of a major malformation is related to a different regional patterning of associated anomalies. The prevalence of CVA was 39% in patients with isolated EA and 7% in those with isolated ARM (p < 0.01). Neural crest-related CVA (aortic arch anomalies, conotruncal defects, and superior vena cava malformations) accounted for 72% of all CVA in patients with isolated EA versus 14% in those with isolated ARM (p < 0.02). In patients with isolated EA, anomalies of the fourth and sixth aortic arch derivatives accounted for 75% of all neural crest related CVA. The present pattern of CVA in infants with EA supports the concept that EA may be related to an abnormal contribution from caudal portion of cephalic neural crest.

An examination of the unintended consequences of the rule-out sepsis evaluation: a parental perspective

In order to document unintended consequences of the "rule-out" sepsis (ROS) evaluation, a survey of parents of infants who had undergone such an evaluation at Primary Children's Medical Center in 1997 was conducted. Sixty parents were interviewed. Parental perceptions of the sepsis evaluation and its impact on their families were recorded. Specific data evaluated included parental anxiety, impact on breastfeeding, perceived complications, financial stress, and parental preferences. The majority of parents found the ROS evaluation very stressful. Parental perception of illness increased significantly after being told the infant would require an ROS evaluation, with nearly 30% of parents, after speaking with a physician, believing their infant might die. Breastfeeding problems were reported by 36% of the mothers. Iatrogenic complications were reported by 33%. Although all infants were covered by some form of insurance, 43% of parents reported financial stress. Forty-two percent of parents would have preferred to be treated at home and all parents would prefer an evaluation that could be accomplished in 24 hours. We conclude that unintended consequences of the ROS evaluation included excessive parental anxiety, cessation of breastfeeding, iatrogenic complications, and financial stress. Suggestions to decrease these adverse consequences are given.