Airway anomalies in patients with congenital diaphragmatic hernia

Rescuing lung development through embryonic inhibition of histone acetylation

A major barrier to the impact of genomic diagnosis in patients with congenital malformations is the lack of understanding regarding how sequence variants contribute to disease pathogenesis and whether this information could be used to generate patient-specific therapies. Congenital diaphragmatic hernia (CDH) is among the most common and severe of all structural malformations; however, its underlying mechanisms are unclear. We identified loss-of-function sequence variants in the epigenomic regulator gene SIN3A in two patients with complex CDH. Tissue-specific deletion of Sin3a in mice resulted in defects in diaphragm development, lung hypoplasia, and pulmonary hypertension, the cardinal features of CDH and major causes of CDH-associated mortality. Loss of SIN3A in the lung mesenchyme resulted in reduced cellular differentiation, impaired cell proliferation, and increased DNA damage. Treatment of embryonic Sin3a mutant mice with anacardic acid, an inhibitor of histone acetyltransferase, reduced DNA damage, increased cell proliferation and differentiation, improved lung and pulmonary vascular development, and reduced pulmonary hypertension. These findings demonstrate that restoring the balance of histone acetylation can improve lung development in the Sin3a mouse model of CDH.

Forty days old infant with Pig Bronchus, presenting with recurrent pneumonia: A Case Report

Background

Pig bronchus is rare and usually asymptomatic, but it may also cause significant respiratory symptoms such as recurrent pneumonia, chronic bronchitis, atelectasis, and difficult airway management in surgical and critical care patients. This study is aimed to examine a case of pig bronchus in which the patient presented with recurrent pneumonia in her early days of life.

Case Report

A case report is the study design utilized in this assessment of a 40-days-old girl from a consanguineous marriage, who presented with cough and difficulty breathing for approximately a month. She was referred from a provincial hospital with no improvement in respiratory symptoms after three times hospitalization since birth. Radiological investigation revealed pig bronchus as the cause of recurrent pneumonia.

Conclusion

Pig bronchi, if not diagnosed on time, may result in severe lung infection that can even result in fatal disease. A high level of clinical suspicion is required to initiate an appropriate diagnostic workup. The gold standard modality for the diagnosis of pig bronchus is computed tomography (CT), ideally with multi-detector three-dimensional (3D) image reconstruction.

Neonatal rodent ventilation and clinical correlation in congenital diaphragmatic hernia

INTRODUCTION

Ventilator management is a critical part of managing congenital diaphragmatic hernia (CDH). We aimed to use a murine model and patient data to study CDH-associated differences in oxygenation, airway resistance, and pulmonary mechanics by disease severity.

METHODS

We used the nitrofen model of CDH. For control and CDH rodents, data were collected within the first hour of life. Oxygen saturations (SpO₂ ) were collected using MouseOx, and large airway resistance and inspiratory capacities were collected using flexiVent. A single-center, retrospective review of term CDH infants from 2014 to 2020 was performed. Tidal volumes were collected every 6 h for the first 48 h of life or until the patient was taken off conventional ventilation. Newborns that were mechanically ventilated but had no pulmonary pathology were used as controls. CDH severity was defined using the CDH Study Group (CDHSG) classification system.

RESULTS

Control rodents had a median SpO₂ of 94% (IQR: 88%-98%); CDH pups had a median SpO₂ of 27.9% (IQR: 22%-30%) (p < 0.01). CDH rodents had lower inspiratory capacity than controls (median: 110 μl, IQR: 70-170 vs. median: 267 μl, IQR: 216-352; p < 0.01). CDH infants had a lower initial SpO₂ than control infants. Overall, CDH infants had lower tidal volumes than control infants (median: 4.2 ml/kg, IQR: 3.3-5.0 vs. 5.4 ml/kg, IQR: 4.7-6.2; p = 0.03). Tidal volumes varied by CDHSG stage.

CONCLUSION

Newborns with CDH have lower SpO₂ and lower, CDHSG stage specific, tidal volumes than control infants. The nitrofen model of CDH reflects these differences. Rodent models may be useful in studying therapeutic ventilatory strategies for CDH infants.

A case of successful slide tracheoplasty for long-segment congenital tracheal stenosis in a neonate with a congenital diaphragmatic hernia and Fallot's tetralogy

Background

Congenital tracheal stenosis (CTS) is a rare and life-threatening airway disorder, which is often associated with cardiac malformations. Among them, neonatal symptomatic CTS with cardiac malformations has an extremely poor prognosis. In contrast to cardiac malformation, congenital diaphragmatic hernia (CDH) has rarely been associated with CTS. We report a neonatal case in which slide tracheoplasty and intracardiac repair were performed simultaneously for CTS and Fallot’s tetralogy (TOF).

Case presentation

An infant with left CDH and Fallot's tetralogy (TOF) was born by cesarean section at 38 weeks of gestation. At the time of resuscitation, a 2.5 mm (ID) endotracheal tube could only be inserted just below the vocal cords. After repairing the CDH at 3 days of age, planned extubation was performed at 7 days of age. However, the patient required re-intubation due to life-threatening episodes after 2 days of the extubation. Enhanced CT revealed a long segment CTS from the upper trachea to the right bronchus (length of stenosis: 40 mm, minimum inner diameter: 2 mm). At 24 days of age, veno-arterial extracorporeal membrane oxygenation (ECMO) was introduced due to severe respiratory failure. At 28 days of age, slide tracheoplasty and palliative right ventricular outflow tract reconstruction (RVOTR) was performed with cardiopulmonary bypass (CPB). After tracheoplasty, a 3.5 mm tracheal (ID) tube could be placed in the reconstructed trachea in a patient with CTS. ECMO was completed 7 days after the operation. On the 17th day after the operation, he was extubated successfully. He was discharged 5 months after birth with home oxygenation therapy.

Conclusions

We reported the successful simultaneous correction of slide tracheoplasty and palliative RVOTR for a neonate with CDH. ECMO was used for respiratory management before and after surgery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40792-022-01422-9.

The Cellular and Molecular Effects of Fetoscopic Endoluminal Tracheal Occlusion in Congenital Diaphragmatic Hernia

Congenital diaphragmatic hernia (CDH) is a complex disease associated with pulmonary hypoplasia and pulmonary hypertension. Great strides have been made in our ability to care for CDH patients, specifically in the prenatal improvement of lung volume and morphology with fetoscopic endoluminal tracheal occlusion (FETO). While the anatomic effects of FETO have been described in-depth, the changes it induces at the cellular and molecular level remain a budding area of CDH research. This review will delve into the cellular and molecular effects of FETO in the developing lung, emphasize areas in which further research may improve our understanding of CDH, and highlight opportunities to optimize the FETO procedure for improved postnatal outcomes.

Anatomical deadspace during resuscitation of infants with congenital diaphragmatic hernia

BACKGROUND

Congenital diaphragmatic hernia (CDH) has a high mortality and morbidity related to pulmonary hypoplasia.

AIMS

To test the hypothesis that CDH infants who survived would have a greater anatomical deadspace reflecting less severe pulmonary hypoplasia. Furthermore, infants with CDH who had undergone feto-tracheal occlusion (FETO) would have a greater anatomical deadspace.

STUDY DESIGN

Infants were studied during resuscitation in the delivery suite. They were all intubated immediately at delivery, given a neuromuscular blocking agent and underwent respiratory monitoring. The anatomical deadspace was calculated from volumetric capnography measurements.

SUBJECTS

Thirty infants born at 32 weeks of gestation or greater and diagnosed antenatally with a CDH were studied. Eleven had undergone FETO and overall five died.

OUTCOME MEASURES

Anatomical deadspace (Vd_ANA) and survival to discharge.

RESULTS

The median (IQR) gestational age of the infants was 38.1 (35.2-39.3) weeks and birthweight 2.8 (2.3-3.3) kg. The anatomical deadspace was higher in those infants who survived (2.9 (2.8-3.3) mls/kg) compared to those who died (2.2 (2.1-2.7) mls/kg; p = 0.003) and was higher in those who had undergone FETO (3.0 (2.8-3.8) mls/kg) compared to those who had not (2.8 (2.4-3.0) mls/kg; p = 0.032). In predicting survival to discharge, the anatomical deadspace had an AUC of 0.90 (p = 0.006).

CONCLUSIONS

CDH infants who survived had a larger anatomical deadspace than those who died suggesting they had less lung hypoplasia. In addition, infants who had undergone FETO had greater anatomical deadspace possibly reflecting distension of the conducting airways.

A new approach using image analysis to assess pulmonary hypoplasia in the fetal lamb diaphragmatic hernia model

BACKGROUND

In congenital diaphragmatic hernia (CDH), there is pulmonary hypoplasia (PH) and also pulmonary vascular and bronchial abnormalities. Few studies have investigated bronchial maldevelopment in CDH. We evaluated bronchial area (BA) by bronchography in a fetal lamb DH model to develop a measure of PH.

METHODS

We created DH in fetal lambs at 75 days gestation, delivering by cesarean section and killing them at term (DH, n = 12). Normal term fetuses provided controls (C, n  = 5). We measured total lung volume (TLV) and performed barium bronchography. Using image analysis, BA, total lung area (TLA) and bronchial area/lung area ratio (B/L ratio) were calculated. Student's T test (p < 0.05; significant) and Spearman's correlation coefficient were performed.

RESULTS

TLV (ml) was 133.3 ± 41.2 in DH and 326 ± 22.5 in C (p = 0.0000001). TLA (cm²) was 78.8 ± 17.4 in DH and 107.1 ± 10.3 in C (p = 0.006). BA (cm²) was 39.6 ± 11.9 in DH and 52.2 ± 7.7 in C (p = 0.019). The B/L ratio was 0.45 ± 0.06 in DH and 0.49 ± 0.05 in C (p = 0.28). There are correlations in DH between TLV and TLA (r = 0.79), TLV and BA (r = 0.73) and in C between TLV and TLA (r = 0.97) and TLV and BA (r = 0.67).

CONCLUSION

It may be possible to assess PH on fetal MRI, given the correlation between TLV and TLA, and TLV and BA.

[Medium and long-term respiratory outcome in patients operated from congenital diaphragmatic hernia: From a series of 56 patients]

INTRODUCTION

Recent advances in prenatal diagnosis, high frequency oscillatory ventilation and pulmonary arterial hypertension (PAH) therapies have progressively improved the survival of patients with congenital diaphragmatic hernia (CDH). However, CDH is associated with high morbidity that affects about half of surviving children. The main sequelae observed are respiratory (asthma, persistent PAH [PPAH], bronchopulmonary dysplasia, respiratory infections) and digestive (gastroesophageal reflux disease [GERD]).

METHOD

This retrospective study focuses on the medium and long-term respiratory evolution of a cohort of 56 children with CDH and operated at Strasbourg University Hospital between 1999 and 2017.

RESULTS

The mean age at assessment was 6,6 years (minimum: 5 months; maximum: 19 years). Seventeen patients (30 %) had asthmatic manifestations. Pulmonary Function Tests (PFT) showed obstructive patterns in 5/11 patients (2 with post-bronchodilator reversibility), and restrictive impairment in 5/11 patients, 3 of whom had thoracic deformity and/or scoliosis. Thirteen patients (23 %) had bronchopulmonary dysplasia. Few patients had recurrent respiratory infections (3.6 %) and chronic respiratory insufficiency (5.3 %). Thirty-nine patients (70 %) presented with an initial PAH, two of whom progressed to PPAH. Sixteen patients (29 %) had thoracic deformity and/or scoliosis and 48 patients (86 %) had GERD, 10 of whom had fundoplication.

CONCLUSION

The long-term respiratory outcome of CDH operated patients is characterized by a moderate prevalence of respiratory symptoms and alterations in PFT that are important to consider in their medical follow-up during adolescence and adulthood. PAH is common in the neonatal period but rarely seems to persist.

Long-term morbidity of congenital diaphragmatic hernia: A plea for standardization

Congenital diaphragmatic hernia (CDH) survivors present long-term morbidities in several systems, including the neurodevelopmental, gastrointestinal, pulmonary, and musculoskeletal ones, and CDH long-term sequelae are increasingly being recognized. Due to high co-morbidity, health related quality of life in a significant proportion of CDH patients might be compromised. As a consequence of consciousness on the long-term sequelae of CDH survivors, and their consequences for life, several follow-up programs were brought to life worldwide. In this review, we will summarize the long-term sequelae of CDH survivors, the impact of new treatments, and analyze the consistency of follow-up programs.

Abnormal lung development in congenital diaphragmatic hernia

The outcomes of patients diagnosed with congenital diaphragmatic hernia (CDH) have recently improved. However, mortality and morbidity remain high, and this is primarily caused by the abnormal lung development resulting in pulmonary hypoplasia and persistent pulmonary hypertension. The pathogenesis of CDH is poorly understood, despite the identification of certain candidate genes disrupting normal diaphragm and lung morphogenesis in animal models of CDH. Defects within the lung mesenchyme and interstitium contribute to disturbed distal lung development. Frequently, a disturbance in the development of the pleuroperitoneal folds (PPFs) leads to the incomplete formation of the diaphragm and subsequent herniation. Most candidate genes identified in animal models have so far revealed relatively few strong associations in human CDH cases. CDH is likely a highly polygenic disease, and future studies will need to reconcile how disturbances in the expression of multiple genes cause the disease. Herein, we summarize the available literature on abnormal lung development associated with CDH.

Complications in neonatal surgery

Neonatal surgery is recognized as an independent discipline in general surgery, requiring the expertise of pediatric surgeons to optimize outcomes in infants with surgical conditions. Survival following neonatal surgery has improved dramatically in the past 60 years. Improvements in pediatric surgical outcomes are in part attributable to improved understanding of neonatal physiology, specialized pediatric anesthesia, neonatal critical care including sophisticated cardiopulmonary support, utilization of parenteral nutrition and adjustments in fluid management, refinement of surgical technique, and advances in surgical technology including minimally invasive options. Nevertheless, short and long-term complications following neonatal surgery continue to have profound and sometimes lasting effects on individual patients, families, and society.

Common Congenital Anomalies of the Central Airways in Adults

The knowledge of airway anatomy is the most fundamental requirement of every bronchoscopist. There are numerous and frequent anatomic variations of the central airways making the examination unique for every individual. It is imperative for every bronchoscopist to be fully cognizant of the common congenital anomalies involving the central airways. Proper identification and reporting of these findings are a matter of the utmost importance, especially when surgical options in a patient with lung cancer or lung transplantation is under consideration. This article focuses on the congenital anomalies of central airway encountered among adults. Each of these anatomic variations has a characteristic appearance, yet requires bronchoscopic acumen for their identification. This review provides a comprehensive description of these anomalies and highlights their clinical implications.

Nonmuscle myosin II regulation of lung epithelial morphology

BACKGROUND

The regulation of epithelial cell shape and orientation during lung branching morphogenesis is not clearly understood. Nonmuscle myosins regulate cell size, morphology, and planar cell polarity. Here, we test the hypothesis that nonmuscle myosin II (NM II) regulates lung epithelial morphology in a spatially restricted manner.

RESULTS

Epithelial cell orientation at airway tips in fetal mouse lungs underwent a significant transformation at embryonic day (E) E17. Treatment of E15 lung explants with the NM II inhibitor blebbistatin increased airway branching, epithelial cell size, and the degree of anisotropy in epithelial cells lining the airway stalks. In cultured MLE-12 lung epithelial cells, blebbistatin increased cell velocity, but left the migratory response to FGF-10 unchanged.

CONCLUSIONS

In the developing lung, NM II acts to constrain cell morphology and orientation, but may be suppressed at sites of branching and cell migration. The regulation of epithelial orientation may therefore undergo dynamic variations from E15 to E17.

Congenital diaphragmatic hernia

Congenital Diaphragmatic Hernia (CDH) is defined by the presence of an orifice in the diaphragm, more often left and posterolateral that permits the herniation of abdominal contents into the thorax. The lungs are hypoplastic and have abnormal vessels that cause respiratory insufficiency and persistent pulmonary hypertension with high mortality. About one third of cases have cardiovascular malformations and lesser proportions have skeletal, neural, genitourinary, gastrointestinal or other defects. CDH can be a component of Pallister-Killian, Fryns, Ghersoni-Baruch, WAGR, Denys-Drash, Brachman-De Lange, Donnai-Barrow or Wolf-Hirschhorn syndromes. Some chromosomal anomalies involve CDH as well. The incidence is < 5 in 10,000 live-births. The etiology is unknown although clinical, genetic and experimental evidence points to disturbances in the retinoid-signaling pathway during organogenesis. Antenatal diagnosis is often made and this allows prenatal management (open correction of the hernia in the past and reversible fetoscopic tracheal obstruction nowadays) that may be indicated in cases with severe lung hypoplasia and grim prognosis. Treatment after birth requires all the refinements of critical care including extracorporeal membrane oxygenation prior to surgical correction. The best hospital series report 80% survival but it remains around 50% in population-based studies. Chronic respiratory tract disease, neurodevelopmental problems, neurosensorial hearing loss and gastroesophageal reflux are common problems in survivors. Much more research on several aspects of this severe condition is warranted.

[Congenital diaphragmatic hernia - mechanisms of pulmonary hypoplasia]

Congenital diaphragmatic hernia (CDH) is a common cause of severe neonatal respiratory distress. Mortality and morbidity are determined by the amount of pulmonary hypoplasia (PH) that occurs and by the development of therapy-resistant pulmonary hypertension. The pathogenesis and aetiology of CDH and its associated anomalies are still largely unknown despite all research efforts. The pathogenesis of CDH is based on an assumption linking herniation of abdominal viscera into the thorax with compression of the developing lung. PH, however, can also result from reduced distension of the developing lung secondary to impaired fetal breathing movements. Our understanding of CDH has also been aided by basic research with the use of dietary, teratogen-induced, and knockout models of CDH. These studies indicate that lung hypoplasia may involve disturbances of mitogenic signalling pathways fundamental to embryonic lung development. Recent data reveal the role of disruption of a retinoid-signalling pathway in the pathogenesis of CDH. Although multifactorial inheritance may best explain most cases of CDH in humans, much has been learned about the genetic factors that play a role in the development of CDH by studies of patients with CDH caused by specific genetic syndromes and chromosome anomalies. More research is warranted to improve our understanding of normal and abnormal lung development in relation to CDH. Such investigations will help in the design of new treatment strategies to improve the natural course or even to prevent this anomaly.

Neonatal tracheal changes following in utero fetoscopic balloon tracheal occlusion in severe congenital diaphragmatic hernia

OBJECTIVE

To report postnatal tracheal changes after in utero fetoscopic balloon tracheal occlusion in severe congenital diaphragmatic hernia (CDH).

DESIGN

Case series.

SETTING

Tertiary care center, CDH National Reference Center.

PATIENTS

Seven consecutive newborn infants with severe CDH who underwent fetoscopic balloon tracheal occlusion.

INTERVENTIONS

Flexible laryngotracheoscopy and histological aspect observed at necropsy in 2 nonsurvivors.

RESULTS

All infants displayed elongation and relaxation of the posterior tracheal wall, intermittently obstructing the lumen during tidal breathing. Whereas the cartilage displayed adequate rigidity, the pars membranacea appeared both flaccid and loose. Tracheal widening (tracheomegaly) was seen in all cases. Histology (n = 2) pointed to structural modifications throughout the pars membranacea, that is, loss of epithelial folding and of longitudinal elastic network and focal muscular disruption. The cartilage displayed no visible or histologic changes. The above tracheal changes were not symptomatic, except for a barking cough during increased respiratory efforts.

CONCLUSIONS

Tracheal widening and intermittent collapse of the posterior wall of the trachea during tidal breathing was found in 7 consecutive newborns who underwent fetoscopic balloon tracheal occlusion, causing mild clinical symptoms. Endoscopic tracheal assessment might provide useful information in children with CDH, in particular, when they underwent in utero fetoscopic balloon tracheal occlusion.

Tracheal innervation is abnormal in rats with experimental congenital diaphragmatic hernia

BACKGROUND

Tracheobronchial motility influences lung development. Lung hypoplasia and lung sequelae accompany congenital diaphragmatic hernia (CDH) in which the vagus nerves and esophageal innervation are abnormal. As the vagus supplies tracheal innervation, this study tested the hypothesis that it might also be abnormal in rats with CDH.

MATERIAL AND METHODS

Intrinsic ganglia were counted and measured in whole mount acetylcholinesterase-stained tracheas from CDH and control E21 fetal rats. The relative surfaces occupied by neural structures were measured in tracheal sections immunostained for p75(NTR) and PGP 9.5. PGP 9.5 protein and mRNA expression were determined. Mann-Whitney tests were used for comparisons between groups using P < .05 as significant.

RESULTS

p75(NTR) staining showed the neural crest origin of tracheal innervation. Scarce neural structures and smaller ganglia were found in CDH fetuses. PGP 9.5 protein expression was decreased in CDH fetuses, whereas PGP 9.5 mRNA levels were increased in comparison with controls.

CONCLUSIONS

Decreased density of neural structures and size of intramural ganglia, reduced expression of neural tissue and PGP 9.5 protein, and increased levels of PGP 9.5 mRNA reveal deficient tracheal innervation in rats with CDH. If similar anomalies exist in the human condition, they could contribute to explaining the pathogenesis of lung hypoplasia and bronchopulmonary sequelae.

Congenital diaphragmatic hernia: current status and review of the literature

Treatment of congenital diaphragmatic hernia (CDH) challenges obstetricians, pediatric surgeons, and neonatologists. Persistent pulmonary hypertension (PPHT) associated with lung hypoplasia in CDH leads to a high mortality rate at birth. PPHT is principally due to an increased muscularization of the arterioles. Management of CDH has been greatly improved by the introduction of prenatal surgical intervention with tracheal obstruction (TO) and by more appropriate postnatal care. TO appears to accelerate fetal lung growth and to increase the number of capillary vessels and alveoli. Improvement of postnatal care over the last years is mainly due to the avoidance of lung injury by applying low peak inflation pressure during ventilation. The benefits of other drugs or technical improvements such as the use of inhaled nitric oxide or extracorporeal membrane oxygenation (ECMO) are still being debated and no single strategy is accepted worldwide. Despite intensive clinical and experimental research, the treatment of newborn with CDH remains difficult.

Lung development and implications for hypoplasia found in congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is associated with various degrees of pulmonary hypoplasia and severe persistent pulmonary hypertension in the newborn. These conditions have significant implications for the outcome for the patient. Defects in early lung development are likely to be central to the generation of hypoplasia. A number of mouse models with defects in pathways that are central to lung development were found to have CDH. Understanding all aspects of early lung development will provide fresh insight into the pathogenesis of CDH and its associated conditions.

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.

Gata4 is necessary for normal pulmonary lobar development

Mutations of Fog2 in mice result in a phenotype that includes pulmonary lobar defects. To determine whether formation of the accessory lobe bronchus is mediated by a Gata family cofactor, we evaluated embryonic lungs from mice carrying missense mutations that cause loss of FOG-GATA protein interaction. Lungs from embryos carrying a missense mutation in Gata6 were structurally normal, while lungs from embryos carrying mutations of either Gata4 or of both Gata4 and Gata6 had a structural phenotype that matched the Fog2 mutant phenotype. Expression analysis showed that Gata4 and Fog2 are expressed in the ventral and medial pulmonary mesenchyme during secondary budding. Although Gata4 has not previously been suspected as playing a role in lung development, we have found that a Fog2-Gata4 interaction is critical for the development of normal pulmonary lobar structure, and this phenotype is not influenced by the additional loss of Gata6 interaction. Fog2 and Gata4 in the early pulmonary mesenchyme participate in patterning the secondary bronchus of the accessory lobe.

Effects of antioxidant vitamins on molecular regulators involved in lung hypoplasia induced by nitrofen

INTRODUCTION

Oxidant herbicide nitrofen (2,4-dichloro-4'-nitrodiphenyl ether) induces in rat embryos congenital diaphragmatic hernia (CDH) with lung hypoplasia. The present study aims at examining whether antioxidant vitamins A, E, and C reverse the effects of the teratogen in the lungs of exposed rats and how they modify the expression of molecular regulators known to be involved in their pathogenesis.

MATERIALS AND METHODS

Wet lung weight-body weight ratio, total DNA, and total protein were determined. Thyroid transcription factor 1 (TTF-1), hepatocyte nuclear factor 3beta (HNF-3beta), and surfactant protein B (SP-B) proteins were measured by immunoblot assay in lung homogenates from rat fetuses exposed in utero to either nitrofen 100 mg intragastrically or vehicle. The coexpression of these factors in the alveolar epithelium was demonstrated by immunohistochemistry. The effects of the addition of vitamins A, C, and E were assessed by comparison with analysis of variance.

RESULTS

Nitrofen decreased lung weight, total DNA, and total protein. The addition of antioxidant vitamins had no effect on lung weight, but increased DNA and protein contents. TTF-1, HNF-3beta, and SP-B proteins were decreased in lung homogenates of exposed rats with CDH. The addition of antioxidant vitamins nearly normalized these values.

CONCLUSIONS

The effects of nitrofen in fetal rat lungs are reversed in part by antioxidant vitamins by upregulating the expression of TTF-1, HNF-3beta, and SP-B. This approach could help to develop transplacental prenatal interventions for CDH.

Long-term follow-up of patients with high-risk congenital diaphragmatic hernia

BACKGROUND/PURPOSE

Recent advances including prenatal diagnosis, high-frequency oscillatory ventilation, and nitric oxide inhalation therapy have gradually improved the survival of high-risk congenital diaphragmatic hernia. However, the factors affecting the long-term outcome of these patients have not been well established.

METHODS

Thirty-three children with ages 4.1 +/- 2.5 years underwent clinical examination including growth measurements, echocardiography, ventilation, and perfusion scintigraphy.

RESULTS

No late death was observed. Common complications were frequent respiratory tract infection (13 patients) and bowel obstruction (5 patients underwent surgery). Although frequent respiratory tract infection decreased with increasing age, patients with frequent respiratory tract infection had a decreased uptake of lung ventilation and perfusion scintigraphy on the affected side and had a decreased height for age and weight for height. No significant difference in lung ventilation and perfusion scintigraphy was observed between patients treated with and without extracorporeal membrane oxygenation, those requiring oxygen more than 1 month, and between those with and without prenatal diagnosis. Patients with a patch repair had decreased uptake on lung perfusion scintigraphy. Although frequent respiratory tract infection may be owing to hypoplasia of the ipsilateral lung, it may impair recovery of the hypoplastic lung.

CONCLUSION

These results indicate that monitoring for respiratory tract infection in addition to nutritional assessment should be required in the follow-up of patients with congenital diaphragmatic hernia at high risk.

Fog2 is required for normal diaphragm and lung development in mice and humans

Congenital diaphragmatic hernia and other congenital diaphragmatic defects are associated with significant mortality and morbidity in neonates; however, the molecular basis of these developmental anomalies is unknown. In an analysis of E18.5 embryos derived from mice treated with N-ethyl-N-nitrosourea, we identified a mutation that causes pulmonary hypoplasia and abnormal diaphragmatic development. Fog2 (Zfpm2) maps within the recombinant interval carrying the N-ethyl-N-nitrosourea-induced mutation, and DNA sequencing of Fog2 identified a mutation in a splice donor site that generates an abnormal transcript encoding a truncated protein. Human autopsy cases with diaphragmatic defect and pulmonary hypoplasia were evaluated for mutations in FOG2. Sequence analysis revealed a de novo mutation resulting in a premature stop codon in a child who died on the first day of life secondary to severe bilateral pulmonary hypoplasia and an abnormally muscularized diaphragm. Using a phenotype-driven approach, we have established that Fog2 is required for normal diaphragm and lung development, a role that has not been previously appreciated. FOG2 is the first gene implicated in the pathogenesis of nonsyndromic human congenital diaphragmatic defects, and its necessity for pulmonary development validates the hypothesis that neonates with congenital diaphragmatic hernia may also have primary pulmonary developmental abnormalities.

Clinical characteristics of children with tracheobronchial anomalies

Tracheobronchial anomalies (TBA) originate between the third and sixteenth week of gestation, and they primarily affect the main bronchi. The reported incidence varies between 1-3% of pediatric endoscopic studies. The objective of our review was to describe the clinical characteristics of patients with TBA diagnosed by flexible bronchoscopy (FB). During the period from March 1993-May 2001, we performed 580 FB at the Pediatric Services of the Catholic University Hospital. During this study period, 52 patients (9.65%) had a TBA (32 males, or 61.5%), with a mean age of 21.2 months (range, 7 days to 6 years). In 39 cases (75%), the diagnosis was made under age 2 years. Thirty-six patients with symptoms related to TBA were symptomatic (70%), and in 16 cases (30%) the TBA was an accidental finding during FB. The main clinical manifestations were recurrent atelectasis of the right upper lobe (RUL), recurrent pneumonia, or congenital stridor. Most of the TBA were localized at the RUL bronchus (47%) and were characterized by an anomaly at its origin, either agenesis or a supernumerary bronchus. Also, we found patients with tracheal bronchus and congenital tracheal stenosis. In 6 patients (12%), we had more than one TBA, the most frequent being the association between RUL and RML anomalies. In 12 cases we found another congenital airway anomaly, mainly laryngomalacia. Patients had associated diseases, such as genetic disorders in 16 cases (particularly Down syndrome), and congenital cardiopathies. In summary, in our clinical experience, TBA are more frequent than previously reported. The majority of young patients have symptoms or signs, and most are localized to the RUL. We found patients with more than one TBA, laryngomalacia associated with TBA, and at a high frequency related to Down syndrome.