Congenital diaphragmatic hernia, what defect?

Human induced pluripotent stem cell-derived lung organoids in an ex vivo model of the congenital diaphragmatic hernia fetal lung

Three‐dimensional lung organoids (LOs) derived from pluripotent stem cells have the potential to enhance our understanding of disease mechanisms and to enable novel therapeutic approaches in neonates with pulmonary disorders. We established a reproducible ex vivo model of lung development using transgene‐free human induced pluripotent stem cells generated from fetuses and infants with Bochdalek congenital diaphragmatic hernia (CDH), a polygenic disorder associated with fetal lung compression and pulmonary hypoplasia at birth. Molecular and cellular comparisons of CDH LOs revealed impaired generation of NKX2.1⁺ progenitors, type II alveolar epithelial cells, and PDGFRα⁺ myofibroblasts. We then subjected these LOs to disease relevant mechanical cues through ex vivo compression and observed significant changes in genes associated with pulmonary progenitors, alveolar epithelial cells, and mesenchymal fibroblasts. Collectively, these data suggest both primary cell‐intrinsic and secondary mechanical causes of CDH lung hypoplasia and support the use of this stem cell‐based approach for disease modeling in CDH.

Fetal lung transcriptome patterns in an ex vivo compression model of diaphragmatic hernia

BACKGROUND

The purpose of this study was to employ a novel ex vivo lung model of congenital diaphragmatic hernia (CDH) to determine how a mechanical compression affects early pulmonary development.

METHODS

Day-15 whole fetal rat lungs (n = 6-12/group) from nitrofen-exposed and normal (vehicle only) dams were explanted and cultured ex vivo in compression microdevices (0.2 or 0.4 kPa) for 16 h to mimic physiologic compression forces that occur in CDH in vivo. Lungs were evaluated with significance set at P < 0.05.

RESULTS

Nitrofen-exposed lungs were hypoplastic and expressed lower levels of surfactant protein C at baseline. Although compression alone did not alter the α-smooth muscle actin (ACTA2) expression in normal lungs, nitrofen-exposed lungs had significantly increased ACTA2 transcripts (0.2 kPa: 2.04 ± 0.15; 0.4 kPa: 2.22 ± 0.11; both P < 0.001). Nitrofen-exposed lungs also showed further reductions in surfactant protein C expression at 0.2 and 0.4 kPa (0.53 ± 0.04, P < 0.01; 0.69 ± 0.23, P < 0.001; respectively). Whereas normal lungs exposed to 0.2 and 0.4 kPa showed significant increases in periostin (POSTN), a mechanical stress-response molecule (1.79 ± 0.10 and 2.12 ± 0.39, respectively; both P < 0.001), nitrofen-exposed lungs had a significant decrease in POSTN expression (0.4 kPa: 0.67 ± 0.15, P < 0.001), which was confirmed by immunohistochemistry.

CONCLUSIONS

Collectively, these pilot data in a model of CDH lung hypoplasia suggest a primary aberration in response to mechanical stress within the nitrofen lung, characterized by an upregulation of ACTA2 and a downregulation in SPFTC and POSTN. This ex vivo compression system may serve as a novel research platform to better understand the mechanobiology and complex regulation of matricellular dynamics during CDH fetal lung development.

The relationship between three signs of fetal magnetic resonance imaging and severity of congenital diaphragmatic hernia

OBJECTIVE

To seek a simple approach for prenatally classifying congenital diaphragmatic hernia (CDH) severity using fetal magnetic resonance imaging (MRI) markers.

STUDY DESIGN

A retrospective, multicenter study using questionnaires to investigate fetal MRI findings. We included fetuses prenatally diagnosed with isolated left-sided CDH and delivered after 36 weeks of gestation. We focused on three fetal MRI morphological signs: incomplete pulmonary baseline (IPB), liver up (LU) and retrocardiac stomach (RCS). We also evaluated the fetal MRI score defined as the total number of positive signs; the primary outcome was survival at discharge.

RESULTS

In 256 patients (from 56 institutions), IPB, LU and RCS findings correlated with lower survival: odds ratio (95% confidence interval), 0.16 (0.08 to 0.33); 0.24 (0.12 to 0.51); and 0.14 (0.07 to 0.28); respectively. Patients with higher fetal MRI scores had a higher mortality rate.

CONCLUSION

IPB, LU and RCS on fetal MRI are related to CDH severity.

Congenital diaphragmatic hernia: defect size correlates with developmental defect

PURPOSE

The aim of our study was to elucidate if the defect size reflects the magnitude of the developmental defect in patients with CDH.

METHODS

All patients recorded in the CDH Study Group registry between January 1, 2007, and December 31, 2010, and with defect classification were included in the study. They were divided according to defect size (A-D) and compared for: gestational age (GA), birth weight (BW), number of abnormal organ systems, prevalence of associated anomalies, cardiovascular malformations (CVM), chromosomal anomalies, liver in the chest, and hernia sac.

RESULTS

A total of 1350 of 1778 patients had defect classification: 173 A, 557 B, 438 C, and 182 D. Mortality rate was 0.6%, 5.3%, 22.6%, and 45.6% in group A, B, C, and D, respectively, (p<0.0001; p for trend <0.0001). GA, BW, prevalence of associated anomalies, particularly CVM, number of abnormal organ systems, and prevalence of sac were significantly different between the groups, with a significant reduction of GA, BW, and prevalence of sac. There was an increase in prevalence of associated anomalies, liver in the chest, and number of abnormal systems as the defect size increased.

CONCLUSION

Defect size is directly correlated with mortality rate, prevalence of other anomalies (particularly CVM), and number of abnormal systems, and inversely with GA, BW, and prevalence of hernia sac. The defect size may be a marker for the magnitude of developmental abnormality, thereby explaining its relationship with the outcome.

Prostanoids in bronchoalveolar lavage fluid do not predict outcome in congenital diaphragmatic hernia patients

Vasoactive prostanoids may be involved in persistent pulmonary hypertension (PPH) in infants with a congenital diaphragmatic hernia (CDH). We hypothesized that increased levels of prostanoids in bronchoalveolar lavage (BAL) fluid would predict clinical outcome. We measured the concentrations of 6-keto-prostaglandin F_1α (6-keto-PGF_1α), thromboxane B₂ (TxB₂), protein, albumin, total cell count, and elastase-α1-proteinase-inhibitor complex in BAL fluid of 18 CDH patients and of 13 control subjects without PPH. We found different concentrations of prostanoids in BAL fluid of CDH patients with PPH: infants with a poor prognosis had either high levels of both 6-keto-PGF_1α and TxB₂ compared to controls, or high levels of 6-keto-PGF_1α only. TxB₂ levels showed a large variability in all CDH patients irrespective of outcome. We conclude that prostanoid levels in BAL fluid do not predict clinical outcome in CDH patients.

Lung eicosanoids in perinatal rats with congenital diaphragmatic hernia

Abnormal levels of pulmonary eicosanoids have been reported in infants with persistent pulmonary hypertension (PPH) and congenital diaphragmatic hernia (CDH). We hypothesized that a dysbalance of vasoconstrictive and vasodilatory eicosanoids is involved in PPH in CDH patients. The levels of several eicosanoids in lung homogenates and in bronchoalveolar lavage fluid of controls and rats with CDH were measured after caesarean section or spontaneous birth. In controls the concentration of the stable metabolite of prostacyclin (6-keto-PGF_1α), thromboxane A₂ (TxB₂), prostaglandin E₂ (PGE₂), and leukotriene B₄ (LTB₄) decreased after spontaneous birth. CDH pups showed respiratory insufficiency directly after birth. Their lungs had higher levels of 6- keto-PGF_1α, reflecting the pulmonary vasodilator prostacyclin (PGI₂), than those of controls. We conclude that in CDH abnormal lung eicosanoid levels are present perinatally. The elevated levels of 6-keto-PGF_1α in CDH may reflect a compensation mechanism for increased vascular resistance.

Pulmonary artery size has prognostic value in low birth weight infants with congenital diaphragmatic hernia

AIM

The aim of this study was to examine the relationship between birth weight, pulmonary artery (PA) size, and outcome in congenital diaphragmatic hernia (CDH) to establish if PA size has prognostic value.

METHODS

The subjects for this study were 39 consecutive left-sided CDH patients treated at our institution according to the same protocol from 2002 to 2009. Other CDH patients with concurrent anomalies that eventually caused death or who became symptomatic more than 6 h after birth were excluded. Birth weight was used to create two groups; low birth weight (LBW; birth weight ≤ 2,500 g; n = 15) and normal birth weight (NBW; birth weight >2,500 g; n = 24). Right PA (RPA) and left PA (LPA) were measured by echocardiography (EC) during late pregnancy (fetal; gestational age (GA): 32-34 weeks), and on days 0, and 2 of life and compared.

RESULTS

Mean birth weights were significantly different between the two groups; however, gender, mean GA, and outcome were similar. In LBW survivors, RPA was significantly larger than in non-survivors. PA size was not related to outcome in NBW.

CONCLUSION

We are the first to show that RPA size has prognostic value in low birth weight infants with left-sided CDH.

Significance of pulmonary artery size and blood flow as a predictor of outcome in congenital diaphragmatic hernia

AIM

To determine if pulmonary artery size and blood flow have prognostic value in congenital diaphragmatic hernia (CDH).

METHODS

Twenty-eight consecutive left-sided CDH patients treated according to a standard protocol with high frequency oscillatory ventilation (HFOV) + nitric oxide (NO) had right and left pulmonary artery (RPA, LPA) diameters, LPA/RPA diameter (L/R) ratios, and PA blood flows examined by echocardiography (EC) on days 0, 2, and 5 after birth and compared prospectively.

RESULTS

Twenty-two patients (78.6%) survived. Of these, 15 required NO (NO-s), and seven did not (non-NO-s). All six patients that died required NO (NO-d). RPA in the NO-d group was significantly smaller than in the NO-s or non-NO-s groups on day 0 (2.90 +/- 0.41 vs. 3.40 +/- 0.49 or 4.01 +/- 0.43; P < 0.01, respectively). LPA in the NO-d group was significantly smaller than in the non-NO-s on day 0 (2.13 +/- 0.45 vs. 3.39 +/- 0.34; P < 0.01). L/R ratios in NO subjects were significantly smaller (NO-s 0.74 +/- 0.11; NO-d 0.73 +/- 0.11) than in non-NO-s subjects (0.84 +/- 0.03) on day 0 (P < 0.01). PA diameters and L/R ratios did not change significantly from day 0 to day 5 in all three groups. There was LPA flow on day 0 in all non-NO-s subjects, but none in all NO subjects. In the NO-s group, LPA flow was confirmed in 87% (13/15) on day 2 and in 100% on day 5, however, there was no LPA flow from day 0 to day 5 in any of the NO-d group.

CONCLUSION

Our data indicate that PA diameters on day 0 and LPA flow are strongly prognostic in left-sided CDH and L/R ratio would appear to be a simple highly reliable indicator of the necessity for NO therapy.

Predictors of outcome in patients with congenital diaphragmatic hernia requiring extracorporeal membrane oxygenation

BACKGROUND

The role of extracorporeal membrane oxygenation (ECMO) in patients with congenital diaphragmatic hernia is still evolving. The use of ECMO is invasive with potential complications during instrumentation for cannulation and heparinization. There are no reliable predictors of outcome in patients requiring ECMO. We aimed to identify (a) the factors that could predict outcome and (b) the incidence and relation of complications during ECMO to outcome.

METHODS

"Pre" ECMO (age, sex, birth weight, blood gasses, and ventilator settings) and "on" ECMO variables (mode of ECMO, use of nitric oxide, surfactant, liquid ventilation, inotropes, timing of repair, and complications on ECMO) were analyzed to identify predictors of outcome.

RESULTS

Fifty-two patients were included. The overall survival was 58%. Mean duration of ECMO (181 +/- 120 vs 317 +/- 156 hours, P = .001), use of nitric oxide (6 vs 10, P = .049), and renal complications (4 vs 14; P < .001) differed between survivors and nonsurvivors. The survival of patients requiring ECMO support for more than 2 weeks is significantly lower than that of patients requiring ECMO support for less than 2 weeks (18% vs 68%, P = .005). Multiple logistic regression revealed ECMO duration of 2 weeks or more and renal complications to be associated with mortality.

CONCLUSION

No pre-ECMO variable could be identified as predictor of mortality. Prolonged duration of ECMO and renal complications on ECMO were independently associated with mortality.

The MRI findings of the right-sided fetal lung can be used to predict postnatal mortality and the requirement for extracorporeal membrane oxygenation in isolated left-sided congenital diaphragmatic hernia

We evaluated whether a correlation existed between fetal pulmonary magnetic resonance imaging (MRI) findings and postnatal mortality, as well as the requirements for extracorporeal membrane oxygenation (ECMO) in infants with prenatally diagnosed, isolated left-sided congenital diaphragmatic hernia (CDH). Twenty-one pregnant women carrying fetuses with CDH underwent 30 MRI scans, and the right-sided fetal lung volume (FLV) was measured. In the control, a regression analysis was performed to associate FLV with gestational age. This yielded a formula that enabled the calculation of the expected right fetal lung volume (ERFLV). In cases with CDH, the right-sided observed FLV/ERFLV (= %RFLV) was compared with both the postnatal mortality and whether ECMO was required. Additionally, we investigated the relationship between the lung shape on MRI (whether there was a complete pulmonary baseline present) and postnatal mortality. The %RFLV was significantly lower in nonsurvivors compared with survivors. Among survivors, the %RFLV was significantly lower in infants who required ECMO compared with those who did not. The pulmonary baseline was completely present in 3 (38%) and 13 (100%) of the nonsurvivors and survivors, respectively. In isolated left-sided CDH, the %RFLV is a good predictor not only of postnatal mortality but also of the requirement for ECMO.

Serum monocyte chemotactic protein-1 levels in congenital diaphragmatic hernia

To measure serum monocyte chemotactic protein-1 (MCP-1) in patients with congenital diaphragmatic hernia (CDH) and investigate its relationship to the development of persistent pulmonary hypertension (PPH). Serum MCP-1 was measured in 13 neonates with high risk for CDH at the time of diagnosis and postoperatively, and in five age-matched controls using an ELISA system. The 13 CDH subjects were divided into four groups according to the presence of PPH and outcome. Group I (severe-pre group): subjects with severe PPH who died prior to surgery (n = 5); Group II (mild-pre group): subjects with mild PPH controlled by medications (n = 8); Group IIa (severe-post group): subjects who subsequently developed severe PPH postoperatively and died (n = 3); and Group IIb (mild-post group): subjects who continued to have mild PPH controlled by medications. We also examined nitrofen-induced hypoplastic lungs from five rat fetuses with CDH and five control lung specimens for MCP-1 using immunohistochemistry. Mean serum MCP-1 in Group I was (1038.0 +/- 95.8 pg/ml), which was significantly higher than Group II (444.9 +/- 39.7 pg/ml) (P < 0.0001) and controls (147.3 +/- 11.3 pg/ml) (P < 0.0001). Postoperatively, Group IIa was significantly higher than Group IIb from 24 to 120 h postoperatively (P < 0.001). In Group IIb serum MCP-1 did not rise at all between 24 and 120 h postoperatively. Hypoplastic fetal rat CDH lungs had strong expression of MCP-1 compared with control lungs. Up-regulated expression and high circulating levels of MCP-1 in CDH patients with PPH suggest that MCP-1 may play a role in the development of PPH in CDH.

Antenatal vitamin A decreases ventilation-induced lung injury in the lamb model of congenital diaphragmatic hernia

OBJECTIVE

Infants with congenital diaphragmatic hernia (CDH) are susceptible to ventilation-induced lung injury. Vitamin A may protect the lung from injury during ventilation. The authors investigated the effects of antenatal vitamin A on ventilation-induced lung injury in CDH lambs using lung myeloperoxidase (MPO) activity as an indicator of lung injury.

METHODS

Left-sided diaphragmatic defects were created in 10 lambs at 79-81 days' gestation. Six CDH lambs had right jugular venous catheters inserted at 120 days' gestation and were given vitamin A until 135 days' gestation. Four CDH lambs were not treated. Twin littermates (n = 3) served as controls. All lambs were delivered at 136-139 days of gestation and ventilated for 2 hours. Lambs were sacrificed following ventilation and samples of left lung were snap frozen. MPO was extracted from lung tissue and MPO activity was assayed.

RESULTS

CDH lambs treated with antenatal vitamin A demonstrated significantly lower MPO activity than untreated CDH lambs (0.0477 +/- 0.0150 vs. 0.1106 +/- 0.0230 units/mg protein, p < 0.05).

CONCLUSION

This is the first study to look at the effect of vitamin A on lung injury in CDH. In the lamb model of CDH, antenatal vitamin A decreases ventilation-induced lung injury.

Cardiopulmonary anatomy and function in long-term survivors of mild to moderate congenital diaphragmatic hernia

BACKGROUND/PURPOSE

In the last decades, several studies regarding cardiopulmonary sequelae in survivors of congenital diaphragmatic hernia (CDH) have been published, but results often are conflicting, and controversies still exist. The aim of this study was to assess cardiopulmonary anatomic and functional outcome in a group of long-term survivors of CDH of mild to moderate degree.

METHODS

Twenty-four children aged 8.15 +/- 2.80 years underwent clinical examination with growth assessment, chest radiographs, echocardiography, pulmonary perfusion scintigraphy, static lung volumes measurement, and spirometry.

RESULTS

Mean Z scores of weight for age and height for age were within normal values. Echocardiography showed normal anatomy and function in all but 3 patients with isolated CDH, in whom minor alterations were detected. Mean perfusion to the affected side was significantly lower (45.16 +/- 5.30%; P <.0001) but still within normal range. Four children showed a substantial impairment of perfusion to the hernia side. The mean spirometric values and pulmonary volumes were normal. However, a mild restrictive pattern was evident in 6 children (27.3%), an obstructive pattern in 3 (13.6%), and a mixed obstructive and restrictive impairment in 1.

CONCLUSIONS

Hypoplastic lungs of mild to moderate CDH survivors continue to cause pulmonary morbidity in some children many years after the correction of the defect. In particular, lung perfusion appears to be impaired in 20% of the patients and pulmonary function in 45%, without any significant cardiac or developmental sequelae. The negative correlation between FEV1 and duration of ventilation at presentation (r = -0.49; P =.026) may be caused by the consequences of lung hypoplasia, but initial ventilatory management may contribute to increased pulmonary morbidity. Relationship between perfusion and FEF25-75 (r = 0.61; p = 0.004) could reflect an equivalent degree of reduction in the caliber of distal airways and pulmonary vascular tree.

Increased levels of circulating adhesion molecules in neonates with congenital diaphragmatic hernia complicated by persistent pulmonary hypertension

The aim of this study was to determine circulating levels of adhesion molecules in serum from patients with congenital diaphragmatic hernia (CDH) to investigate the relationship between soluble ICAM-1, ELAM-1, and VCAM-1 liberated by activated vascular endothelium and the development of persistent pulmonary hypertension (PPH) in patients with CDH. We measured serum levels of ICAM-1, ELAM-1, and VCAM-1 in 20 high-risk neonates with CDH at the time of diagnosis (11 with PPH and 9 without PPH) and 7 age-matched controls using ELISA system. We further examined the lungs of 5 patients with CDH complicated by PPH who died during resuscitation and stabilization, and three control lung specimens for the expression of adhesion molecules using immunohistochemistry. The mean serum ICAM-1 levels in CDH patients with PPH (227.0+/-98.9 ng/ml) were increased compared with levels in CDH patients without PPH (140.29+/-37.4 ng/ml; p<0.05) and controls (130.0+/-23.8 ng/ml; p<0.05). Mean serum ELAM-1 levels in CDH patients with PPH (116.5+/-19.2 ng/ml) were significantly increased compared with levels in CDH patients without PPH (79.3+/-27.9 ng/ml; p<0.01) and controls (58.4+/-14.5 ng/ml; p<0.001). Mean serum VCAM-1 levels in CDH patients with PPH (1596.9+/-460.4 ng/ml) were significantly higher compared with levels in CDH patients without PPH (1069.3+/-444.6 ng/ml; p<0.01) and controls (838.0+/-171.2 ng/ml; p<0.001). But serum adhesion molecule levels in CDH patients without PPH were no different from controls statistically. Pulmonary vascular endothelial cells from CDH lung with PPH had strong expression of adhesion molecules compared with controls. Up-regulated expression of adhesion molecules on the endothelium of pulmonary vessels and high circulating levels of adhesion molecules in CDH patients with PPH suggest that adhesion molecules may play a role in the development of PPH in CDH.

Congenital diaphragmatic hernia: an evaluation of the prognostic value of the lung-to-head ratio and other prenatal parameters

OBJECTIVES

A retrospective analysis of the prognostic significance of the lung-to-head ratio (LHR) and other prenatal parameters on the outcome of fetuses with left-sided congenital diaphragmatic hernia (CDH).

METHODS

A total of 26 fetuses with isolated left CDH without chromosomal abnormalities were included. Twenty-one LHR measurements could retrospectively be calculated from the last available ultrasonographic recordings before birth. The relationship between LHR and fetal outcome and the gestational age dependency of this relation was tested. Cutoff levels as previously published were applied to determine their predictive value in this population. The association between other prenatal predictive variables and fetal outcome was also determined. Survival was defined as discharge from the hospital.

RESULTS

The overall survival rate was 50%. There was a statistically significant difference between the mean LHR of the survivors compared to the mean LHR of the nonsurvivors (1.78 vs 1.02), whereas the mean gestational age of these two groups did not differ. LHR was not gestational age dependent in the prediction of fetal outcome. The cutoff levels LHR <1, 1-1.4, >1.4 showed a good applicability in the prediction of fetal outcome within the present study population with a 100% survival if LHR >1.4 and a 100% mortality if LHR <1. An intrathoracic position of the stomach, mediastinal shift, polyhydramnios as individual variables and early diagnosis (<25 weeks' gestation) revealed to be poor sonographic predictors for fetal outcome.

CONCLUSION

LHR proved to be a good predictor for fetal outcome, independent of gestational age at the time of the measurement. To substantiate our observation, a prospective multicenter study is warranted.

Gene expression of fibroblast growth factors 10 and 7 is downregulated in the lung of nitrofen-induced diaphragmatic hernia in rats

BACKGROUND/PURPOSE

Newborns with congenital diaphragmatic hernia (CDH) still have a high mortality rate, which has been attributed to pulmonary hypoplasia and pulmonary hypertension. Fibroblast growth factors (FGFs) are essential components of the gene network that regulates lung development. Recent studies suggest that the new member of FGF family, FGF-10, plays a fundamental role in branching morphogenesis and is essential for lung formation. FGF-10-deficient mice exhibit complete absence of lungs. FGF-7 promotes epithelial proliferation and expansion leading to the formation of cystlike structures. The aim of this study was to determine the gene level expression of FGF-10 and FGF-7 in the lung of nitrofen-induced CDH.

METHODS

Congenital diaphragmatic hernia (CDH) was induced in pregnant rats after administration of 100 mg of nitrofen on day 9.5 of gestation (term, 22 days). In control animals, the same dose of olive oil was given without nitrofen. Cesarean section was performed on day 21 of gestation. The fetuses were divided into 3 groups: normal controls (n = 16), nitrofen induced without CDH (n = 16), and nitrofen-induced CDH (n = 16). Total RNA and DNA were extracted from the lung in each group and measured. mRNA was extracted from total RNA. Reverse transcription polymerase chain reaction (RT-PCR) was performed to evaluate mRNA expressions of FGF-10 and FGF-7. Levels of mRNA were expressed as a ratio of the band density divided by that of beta-actin, a house-keeping gene.

RESULTS

FGF-10 mRNA expression was decreased significantly in CDH lung (2.914 +/- 0.320) compared with controls (4.062 +/- 0.307; P <.05) and nitrofen induced without CDH lung (3.923 +/- 0.250; P <.01). FGF-7 mRNA expression was decreased significantly in CDH lung (0.777 +/- 0.097) compared with controls (1.028 +/- 0.093; P <.01).

CONCLUSIONS

Decreased gene expression of FGF-10 and FGF-7 in the hypoplastic lung suggests that pulmonary hypoplasia in nitrofen-induced CDH rat may be caused by reduced synthesis of FGF-10 and FGF-7 during lung morphogenesis.

Altered gene level expression of thyroid hormone receptors alpha-1 and beta-1 in the lung of nitrofen-induced diaphragmatic hernia

PURPOSE

Thyroid receptor alpha-1 (TR-alpha1) and thyroid receptor beta-1 (TR-beta1) are thought to be essential for the fetal and postnatal development of the lung. The authors investigated gene level expression of TR-alpha1 and TR-beta1 in the lung of nitrofen-induced congenital diaphragmatic hernia (CDH) using reverse transcription polymerase chain reaction (RT-PCR).

METHODS

CDH was induced in pregnant rats after administration of 100 mg nitrofen on day 9.5 of gestation. Cesarean section was performed on day 21 of gestation. The fetuses were divided into 3 groups: normal controls (n = 16), nitrofen-induced CDH (n = 16), and nitrofen-treated without CDH (n = 16). mRNA was extracted from the left lung in each group. RT-PCR was performed to evaluate mRNA expressions of TR-alpha1 and TR-beta1. Levels of mRNA were expressed as a ratio of the band density divided by that of beta-actin, a house-keeping gene.

RESULTS

TR-alpha1 mRNA expression was decreased significantly in CDH lung (1.618 +/- 0.148) compared with controls (2.658 +/- 0.251; P <.01) and nitrofen-treated without CDH lung (2.232 +/- 0.193; (P <.05). TR-beta1 mRNA expression also was significantly decreased in CDH lung (2.223 +/- 0.270) compared with controls (3.569 +/- 0.262; P <.01) and nitrofen-treated without CDH lung (3.235 +/- 0.299; P <.05).

CONCLUSION

These data suggest that the downregulation of thyroid hormone signaling pathway through altered expression of TR-alpha1 and TR-beta1 during lung morphogenesis may be a contributory factor in the pathogenesis of pulmonary hypoplasia in nitrofen-induced CDH.

Neurodevelopmental outcome after congenital diaphragmatic hernia: Extracorporeal membrane oxygenation before and after surgery

BACKGROUND/PURPOSE

Extracorporeal membrane oxygenation (ECMO) as a treatment of last resort for neonates with persistent pulmonary hypertension of the newborn (PPHN) caused by congenital diaphragmatic hernia (CDH) may be used for preoperative stabilization or postoperative rescue. The aim of this study was to examine the acute and long-term morbidity associated with pre- and postoperative ECMO.

METHODS

Neonates born with CDH and needing ECMO were classified into 2 groups. Group 1 consisted of neonates placed on ECMO after CDH surgery. Patients in group 2 underwent preoperative ECMO stabilization. Medical records after birth were evaluated. Growth, neuromotor and cognitive development, hearing, and behavior were evaluated. Student t test and chi(2) were used to determine statistical significance between groups.

RESULTS

Subjects in group 2 had significantly more days on ECMO and loop diuretics. Alkalosis was induced for a longer duration in group 2. At follow-up 3 to 9 years later, no differences were found between the 2 groups in growth parameters, neuromotor outcome, or behavior. However, in group 1, 2 of 9 children had significant hearing impairment necessitating amplification compared with 6 of 6 subjects in group 2.

CONCLUSIONS

Neonates with CDH first stabilized on ECMO (group 2) had a higher incidence of hearing loss compared with those needing ECMO postrepair (group 1). The etiology of this finding is not clear. This may be secondary to the prolonged period of hyperventilation or general intensive care that is part of the protocol for neonates who are electively stabilized on ECMO preoperatively. J Pediatr Surg 36:539-544.

Remodeling of pulmonary arteries in human congenital diaphragmatic hernia with or without extracorporeal membrane oxygenation

PURPOSE

The aim of this study was to describe in detail the perinatal developmental profile of the pulmonary vasculature in congenital diaphragmatic hernia (CDH) and to examine the potential beneficial effects of extracorporeal membrane oxygenation (ECMO) on the vascular morphology. Additionally the authors aimed to identify the differences in pulmonary vascular morphology among CDH cases according to the primary cause of death: either extreme lung hypoplasia (LH) or persistent pulmonary hypertension (PPH).

METHODS

The authors studied autopsy sections from 30 high-risk CDH cases with respect to the pulmonary arteries in relation to gestational age (GA) and ECMO treatment. They were grouped into CDH-I: 20 cases with GA greater than 34 weeks who were not subjected to ECMO and CDH-II: 10 cases with GA greater than 34 weeks, who were subjected to ECMO for an average time of 237 hours. Five age-matched neonates who died from placental insufficiency or birth asphyxia without evidence of lung hypoplasia served as controls (CON). Medial and adventitial thicknesses of pulmonary arteries were measured in lung sections stained with Elastic van Gieson by 2 investigators blinded for the clinical data. Immunohistological staining with anti-alpha-smooth muscle actin (alpha-SMA) was performed to confirm the precise location of the arterial media before morphometry. CDH cases were subgrouped and compared according to the primary cause of death. Unpaired Student t test was used for statistics, with significant P value < or =.05.

RESULTS

In CDH newborns, a significant increase in medial, adventitial, and total wall thickness was found in pulmonary arteries with an external diameter of less than 200 microm as compared with age-matched controls (P<.004, .0001, and .0009, respectively). ECMO-treated CDH newborns showed a significantly thinner arterial adventitia than CDH patients who did not receive this treatment (P<.0001), approaching normal values. However, the medial thickness remained increased. Morphometrically, no significant differences in CDH cases between patients dying of PPH or severe LH could be determined.

CONCLUSIONS

(1) In CDH, there is failure of the normal arterial remodeling processes occurring in the perinatal period. (2) Pulmonary vascular morphology in CDH does not differ between the groups with lung hypoplasia or persistent pulmonary hypertension as primary cause of death. (3) Adventitial thinning of these arteries might be one of the mechanisms by which ECMO alters PPH in CDH cases.

Fetal stabilization for antenatally diagnosed diaphragmatic hernia

BACKGROUND/PURPOSE

Infants with congenital diaphragmatic hernia have pulmonary hypoplasia resulting in persistent pulmonary hypertension of neonates (PPHN), which is the main contributor to both high mortality and morbidity. The pulmonary artery bed in patients with congenital diaphragmatic hernia (CDH) is underdeveloped and is very sensitive to slight stimuli. It is, therefore, vital to avoid any factors that might increase pulmonary vascular resistance during the perinatal treatment of these patients. Recently, fetal anesthesia for perinatal stabilization in patients with CDH has been reported. However, the efficacy of this method remains controversial. The aim of this study is to analyze the benefits of fetal stabilization using fetal anesthesia in patients with CDH.

METHODS

The authors have seen 9 cases of antenatally diagnosed CDH and attempted fetal stabilization. The indication for fetal stabilization was a lung thoracic ratio of less than 0.2, without any severe associated anomalies. The protocol for fetal stabilization was (1) monitoring the fetal respiratory movement and heart beat by ultrasonography, (2) the administration of morphine (20 to 30 mg) and diazepam (5 mg) to the mother, (3) the confirmation of any interruptions in fetal movement followed by a cesarean section, (4) pancuronimum (0.5 mg) was given through the umbilical vessels, (5) intubation before clamping of the umbilical cord, and (6) high-frequency oscillatory ventilation (HFO) without bagging.

RESULTS

The lung-thratic ratio (LTR) was between 0.06 to 0.17 (average, 0.10+/-0.04). Operation was performed in 7 of 9 patients at between 2.5 and 27 hours after birth. The overall survival rate was 66.7% (6 of 9). All of the patients who underwent operation within 5 hours after birth survived.

CONCLUSIONS

Perinatal stabilization using fetal anesthesia was found to be effective in preventing PPHN and shortening the period of preoperative stabilization. It also improved the survival rate of patients with severe CDH.

Cardiovascular malformations in congenital diaphragmatic hernia: human and experimental studies

BACKGROUND/PURPOSE

Cardiovascular malformations (CVM) associated with congenital diaphragmatic hernia (CDH) account in part for the high mortality caused by this defect. The aim of this study is to examine the nature of these malformations in a large series of autopsies and to assess if similar defects are also present in rat fetuses with experimental CDH.

METHODS

The incidence of CVM and their nature were examined in the autopsy records of 136 stillborns and neonates with CDH admitted to our institution in the last 30 years. Experimental CDH was induced in rat fetuses by giving 100 mg of nitrofen to their mothers on gestational day 9.5, and the fetuses were harvested on day 21 (near full term). The presence of CDH and the anatomy of the heart and great vessels were studied under dissecting microscope after formalin fixation. Unexposed fetuses were used as controls.

RESULTS

Thirty-three newborns with CDH (24%) had CVM, either isolated or associated with other defects, and 7 had heart hypoplasia. Most CVM (ventricular septal defect, tetralogy of Fallot, transposition of the great vessels, double-outlet right ventricle) involved the outflow tract. In our animal experiments, no malformations were found in 21 control pups. Conversely, 80 of 130 nitrofen-exposed fetuses (61%) had CDH, and 59 of them (74%) had CVM. A significant association (Fisher's Exact test, P<.01) was found between CDH and CVM because only 25 of the 50 exposed animals without CDH (50%) had CVM. Again, most defects involved the outflow tract and were similar to those seen in human CDH (tetralogy of Fallot, persistent truncus, ventricular septal defect, double-outlet right ventricle, aberrant right subclavian artery, agenetic ductus, and interrupted aortic arch). Animals with CDH had significantly decreased heart weight to fetal weight ratio in comparison with controls and with those without CDH.

CONCLUSIONS

The similar nature of the cardiovascular defects found in babies succumbing to CDH and in nitrofen-exposed rats suggests that a similar disturbance of the regional organogenesis related to the neural crest might be involved in both settings, and further validates the use of this animal model for clarifying the cellular and molecular pathogenetic mechanisms.

Calcitonin gene-related peptide expression is altered in pulmonary neuroendocrine cells in developing lungs of rats with congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is associated with high neonatal mortality from lung hypoplasia and persistent pulmonary hypertension. Pulmonary neuroendocrine cells (PNEC) produce calcitonin gene-related peptide (CGRP), a potent vasodilator. We previously reported altered distribution of CGRP-positive PNEC in full-term rats with CDH, that may lead to an imbalance in vasoactive mediators. In the present study we examined the expression of CGRP-positive PNEC during lung development in rats with CDH induced by 2,4-dichlorophenyl-p-nitrophenylether (Nitrofen). Cesarean sections were performed on Days 16, 18, 20, or 22, and the lungs were immunostained for CGRP and immunoreactive cells were quantitated through image analysis. On Day 16, CGRP-immunoreactive staining was negative; on Day 18, CGRP-immunoreactive cells were found in all controls (not exposed to Nitrofen), whereas in CDH pups, CGRP-positive cells were present in only four of six cases. On Day 20, CGRP immunoreactivity was similar in CDH pups, Nitrofen-exposed pups without CDH, and controls. On Day 22 (term), significantly more CGRP-positive cells (i.e., number of positive cells per surface area [mm2] or lung volume [mm3]) were found in ipsilateral lungs of CDH pups than in controls (P < 0.05). The difference was even more striking in contralateral lungs of CDH pups (P < 0.001), ruling out nonspecific effects of Nitrofen. In CDH lungs, the proportion of immunostained epithelium and the size of the neuroendocrine cell clusters (neuroepithelial bodies [NEB]) were not significantly different from those of controls. On Day 22, supraoptimal dilution immunocytochemistry yielded similar results in CDH pups and controls. We conclude that in CDH, CGRP expression in PNEC and NEB is delayed during early stages of lung development. Because CGRP also exhibits growth factor-like properties for endothelium and epithelial cells, the lack of this factor during a crucial developmental stage (canalicular period) may be causally related to lung hypoplasia.

Differential display of genes in normal and hypoplastic fetal murine lungs

To evaluate lung development at the level of gene expression, a comparison was made between normal and hypoplastic murine fetal lungs by using the mRNA differential display technique. We focused on altered gene expressions at gestational day (Gd) 19 in normal and hypoplastic murine lungs. Hypoplastic fetal lungs were created by gavaging pregnant mice at Gd8 with 25 mg of nitrofen (2,4-dichlorophenyl-p-nitrophenyl ether) [1]. Normal as well as gavaged mice were euthanized by an overdose of halothane at Gd19, and fetuses were removed by laparotomy. Lungs were excised and total RNA was extracted from normal and hypoplastic fetal lungs. Differential display technique was carried out using the RNAimage kit (GenHunter Corp., TN). Each reverse transcription and polymerase chain reaction (RT-PCR) was performed using one specific anchor primer H-T11M (5'HindIII-T11A/C/G3') and one arbitrary primer. We have used a total of 3 different anchor primers and 24 arbitrary primers for each sample. There were 20 differentially expressed cDNA clones, either induced, inhibited, enhanced, or reduced in hypoplastic fetal lungs as compared to normal. Of these, one clone (NL2) with reduced expression in Gd19 hypoplastic lungs had 100% homology with mouse nucleosome assembly protein I gene. Another clone (NT5) with induced expression in hypoplastic lungs is an unknown gene. Further, analyses of Northern blots of lungs from various gestational ages showed that the expression of NT5 was induced in hypoplastic lungs at Gd18, whereas in normal lungs it was first expressed at the neonatal stage and was increasingly expressed into adulthood. There is a single hybridized band, approximately 400 bp long for NT5 message. Dexamethasone induced expression of NT5 in normal Gd14 pseudoglandular lungs cultured for 7 days; however, different growth factors did not. Northern blot hybridization of multiple adult mice tissues showed NT5 expression in the lung, intestine, and spleen. The thyromimetic action of nitrofen and the interactive functional pathways of dexamethasone with T3 are known. Therefore, we suggest that the isolation and characterization of NT5 may provide valuable information on the regulation of lung development.

Pulmonary vascular balance in congenital diaphragmatic hernia: enhanced endothelin-1 gene expression as a possible cause of pulmonary vasoconstriction

BACKGROUND

Pulmonary hypoplasia and persistent pulmonary hypertension (PPH) are the principal causes of the ongoing mortality in congenital diaphragmatic hernia (CDH) presenting with respiratory insufficiency within 6 hours after birth. Endothelin-1 (ET-1) is an endothelial-derived vasoconstrictor, which could play an important role in modulating pulmonary vascular tone in PPH. ET-1 exerts its role in controlling vascular tone through two different subtype receptors, endothelin-A receptor (ETA) which is responsible for vasoconstriction and endothelin-B receptor (ETB) which is responsible for vasodilatation by induction of nitric oxide synthase.

METHODS

We examined the pulmonary expression of ET-1, ETA and ETB mRNAs in a rat model of CDH. CDH was induced in rats by administration of 100 mg of nitrofen dissolved in olive oil on day 10 of gestation. Fetal lungs were collected after cesarean section on gestational day 22 (term) and processed for Northern blot analysis and quantitative polymerase chain reaction (PCR).

RESULTS

Significantly (P<.05) enhanced levels of ET-1 mRNA were observed in CDH rats compared with control rats. In contrast to equal levels of ETB mRNA, a two- to fourfold increase in ETA mRNA levels were observed in CDH as compared with control rats.

CONCLUSIONS

The upregulated expression of ET-1 and ETA receptor mRNA before birth strongly support the reason for pulmonary vasoconstriction and altered pulmonary vascular muscularization in CDH. Consequently in the clinical setting, the use of endothelin receptor blockade for the treatment of PPH may be considered against the background of the unpredictable and variable response to inhaled nitric oxide in newborns with CDH.

Abnormal expression of pulmonary bombesin-like peptide immunostaining cells in infants with congenital diaphragmatic hernia

Infants with congenital diaphragmatic hernia (CDH) have a high neonatal mortality and morbidity owing to lung hypoplasia and persistent pulmonary hypertension. Pulmonary neuroendocrine cells produce bombesin-like peptide (BLP), a peptide with growth factor-like properties involved in lung development. We examined the expression of BLP immunostaining in pulmonary neuroendocrine cells (PNEC), and in clusters of these cells called neuroepithelial bodies (NEB), in the lungs of three groups of infants: patients with CDH, newborns with lung hypoplasia due to other causes, and control subjects without lung abnormalities. Morphometric analysis included: 1) percent immunostained airways; 2) percent immunostained epithelium (i.e. frequency of PNEC and NEB); and 3) NEB size. Controls and infants with lung hypoplasia did not differ with respect to BLP immunostaining. The ipsilateral and the contralateral lungs in CDH had a similar BLP immunostaining pattern of PNEC and NEB. The BLP immunostaining varied between CDH cases, possibly due to the differences in clinical presentation. The mean NEB size was significantly increased in infants with CDH compared with the other two groups (p = 0.02). Some CDH cases with large NEBs also showed a high percentage of immunostained epithelium. Lung-body weight ratio correlated positively with percent immunostained airways, and negatively with the NEB size. We conclude that in lungs of CDH patients BLP immunostaining in PNEC and NEB differs from that of infants with lung hypoplasia due to other causes and controls. The increased BLP immunostaining observed in some cases of CDH might reflect a compensatory mechanism related to impaired lung development and/or failure of neuropeptide secretion during neonatal adaptation.

How often is extracorporeal membrane oxygenation needed in cases of congenital diaphragmatic hernia?

Some newborns with congenital diaphragmatic hernia (CDH) and severe pulmonary hypertension cannot be saved by conventional treatment and may obtain some benefit from extracorporeal membrane oxygenation (ECMO) as a bridging measure until adequate hematosis is possible. Early prediction of the insufficiency of "optimal" assistance is still unclear; we reviewed our recent experience with CDH patients in an attempt to evaluate the real need for ECMO in our institution. Between 1987 and 1994, 47 newborns with CDH manifested in the first 24 h were treated with maximal ventilatory assistance (including high-frequency ventilation in 12 cases) and vasoactive drugs prior to surgical repair. In order to summarize the ventilatory and blood-gas parameters, we determined oxygenation index (OI) and ventilatory index (VI) and compared the results in survivors and nonsurvivors. Overall survival was 60% (2 cases of Fryns' syndrome were excluded from analysis). OI was 10.3±5.7 (mean ± SD) for survivors and 46.2 ± 37.8 for nonsurvivors (P < 0.01). VI was 460.9±303 and 1,532±500.6, respectively (P <0.01). Bayesian analysis and receiver operating characteristic curves enabled us to select a threshold value of OI of 20 as the best means of predicting survival in our current conditions (sensitivity: 0.7, specificity: 0.83). The generally accepted figure of 40 had a sensitivity of 1 but a specificity of only 0.44. For VI, the best threshold value was 1,100 (sensitivity: 0.93, specificity: 0.94), whereas the generally used figure of 1,000 had 0.89 and 1, respectively. According to our results, with our current management conditions, approximately 50% of our CDH patients might have obtained some benefit from ECMO.

Congenital eventration of the diaphragm - 45 years' perspective

Fifty-five children with congenital eventration of the diaphragm were operated upon in a single tertiary-care children's hospital during the 45-year period from 1948 to 1992. The study was divided into three periods: 1948-1962, 1963-1977, 1978-1992. There were 14 patients in the first group, 26 in the second, and 15 in the third. Children later in the series presented earlier and with more acute symptoms. Mortality was related to severe pulmonary hypoplasia and associated anomalies, especially chromosomal defects: 14% during the first period, 27% during the second, and 7% during the third.

Prenatal hormonal therapy improves pulmonary compliance in the nitrofen-induced CDH rat model

Neonates with congenital diaphragmatic hernia (CDH) experience a high mortality despite intensive medical and surgical management. The associated pulmonary hypoplasia is accompanied by an underlying biochemical deficiency that bears similarity to respiratory distress syndrome (RDS) in the premature newborn. Using therapies extrapolated from those used to treat RDS, the authors have previously shown correction of the immature pulmonary biochemical indices in the nitrofen rat CDH model. This study investigates the functional and histological outcome of prenatal hormone therapy on CDH rats. Compared with saline-treated CDH controls, dexamethasone-treated CDH animals achieved significant increases in lung distensibility (P = .0006) and functional residual capacity (P = .004); CDH rats treated with combined dexamethasone and thyrotropin-releasing hormone (TRH) showed improved functional residual capacity (P = .043) and alveolar stability (P = .025); CDH animals treated with TRH alone (TRH-CDH) showed no improvement in any parameter tested. Histologically, the lungs from dexamethasone- and dexamethasone-TRH-treated CDH animals showed changes that included narrow septal walls, increased air saccule size, and thinning of the pulmonary interstitium compared with the lungs of saline or TRH-CDH rats, which were developmentally arrested at the canalicular stage. Lung weights and lung weight-body weights ratios were similar in all CDH rats, confirming that treatment did not impair pulmonary growth. These results support the potential clinical use of prenatal pharmacological therapies to treat human fetuses with prenatally diagnosed CDH.

Repair of congenital diaphragmatic hernia after weaning from extracorporeal membrane oxygenation

Stabilization and delayed operation for patients with congenital diaphragmatic hernia (CDH) is now widely accepted. When preoperative extracorporeal membrane oxygenation (ECMO) is needed, most centers have CDH repaired on ECMO to minimize the risk of postoperative deterioration. The authors adopted a policy of weaning from ECMO before repair in an effort to avoid hemorrhagic risks. They reviewed their experience with CDH patients who required ECMO for stabilization before repair but for whom post-ECMO repair was planned. The records of all high-risk CDH patients with a gestational age of at least 34 weeks were reviewed. Eighteen patients were identified. None of the eight who were stabilized and operated on without ECMO required bypass postoperatively; all survived. Ten were placed on bypass, nine for stabilization before repair. Of the nine, seven (78%) were weaned from ECMO to conventional ventilation. Repair of the diaphragmatic defect was performed an average of 3.8 days later; none of these patients had severe pulmonary hypertension postoperatively, and all survived. Two could not be weaned before repair, one of whom had a complex congenital heart defect. This patient died. The other patient had repair on ECMO because of intrathoracic gastric volvulus. Severe blood loss prompted decannulation, and the patient died. One patient who was placed on bypass was transferred 10 days after having had repair elsewhere (at 4 hours of age). Pulmonary hypertension did not resolve, and the postmortem examination showed alveolar capillary dysplasia, with focal misalignment of the pulmonary vessels.(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar epithelial composition and architecture of the late fetal pulmonary acinus: an immunocytochemical and morphometric study in a rat model of pulmonary hypoplasia and congenital diaphragmatic hernia

The aim of the present study was to compare the architecture and alveolar epithelial cell composition of the pulmonary acinus in hypoplastic and normal fetal rat lungs. For this purpose, a rat model of pulmonary hypoplasia in association with congenital diaphragmatic hernia (CDH) induced by Nitrofen (100 mg on day 10 of pregnancy) was studied. Sections (5 microns) from lungs of control and Nitrofen-exposed fetal Sprague Dawley rats with or without CDH aged 18-22 days (vaginal plug on day 1, birth on day 23) were stained with hematoxylin and eosin. To identify developing alveolar epithelial cells, sections were incubated with anti-surfactant protein A (SP-A; rabbit anti-mouse) or preimmunization serum (indirect immunofluorescence). On days 18 and 19, control lungs and exposed lungs from fetuses with and without CDH looked similar (pseudoglandular stage of lung development). The prospective pulmonary acinus consisted of acinar tubules with small round lumens, lined by cuboid, fluorescent type II cells. Morphometric analysis on day 19 showed significantly smaller lung volumes and lung tissue volumes after Nitrofen exposure. On day 20 (canalicular stage), some tubules were slightly dilated and lined by cuboid and thinner fluorescent cells; these dilated tubules were less numerous in lungs from exposed fetuses with CDH. On days 21 and 22 (saccular stage), the saccular lining consisted of cuboid to thin fluorescent cells in exposed lungs from fetuses with and without CDH, and fluorescent (low) cuboid cells interspersed with dark zones (type I cell areas) in control lungs. In the exposed lungs from fetuses with CDH, the lumens of all airspaces were frequently slit-like, and the septa were thicker. These phenomena gave the lungs a primitive, compact aspect. Morphometric analysis on day 22 showed smaller lung volumes and lung tissue volumes, smaller airspace/tissue ratios, smaller epithelial surface areas, and more type II cells per surface area in Nitrofen-exposed lungs than in normal control lungs. The results suggest that Nitrofen-exposed, and thus hypoplastic, fetal rat lungs are retarded with respect to the differentiation of cuboid type II cells into squamous type I cells whether or not CDH is present, and with respect to the development of the future airspaces between days 20 and 22 if CDH is present.

Ultrastructural features of alveolar epithelial cells in the late fetal pulmonary acinus: a comparison between normal and hypoplastic lungs using a rat model of pulmonary hypoplasia and congenital diaphragmatic hernia

The aim of this study was to describe and compare the ultrastructural features and functional maturity of alveolar epithelial cells in hypoplastic and normal fetal rat lungs. Pulmonary hypoplasia in association with congenital diaphragmatic hernia was induced in fetuses by administration of 2,4-dichlorophenyl-p-nitrophenylether (Nitrofen) to pregnant Sprague Dawley rats (100 mg on day 10 of gestation). Lung tissue of Nitrofen-exposed and control fetal rats aged 19-22 days (vaginal plug day 1, birth day 23) was embedded in Epon. Semithin (1 micron) toluidine blue-stained sections were examined by light microscopy; ultrathin sections (approximately 80 nm) were studied via transmission electron microscopy. In bronchoalveolar lavage fluid from control and Nitrofen-exposed fetuses (day 22), phospholipid fractions and surfactant protein A content were measured semiquantitatively. On day 19 both control and Nitrofen-exposed lungs contained only cuboid alveolar epithelial cells; from day 20 there were cuboid, low cuboid, and thinner epithelial cells. The (low) cuboid cells contained large glycogen fields, some precursory stages of multilamellar bodies (MLBs), and just a few mature MLBs on day 19 and 20; smaller glycogen fields, more precursory stages, and more mature MLBs on day 21; and little or no glycogen but many precursory stages and mature MLBs on day 22. The thinner cells contained little or no glycogen and a few precursory stages of MLBs on days 20-22; very thin cells on day 22 contained neither glycogen nor any precursory stages of MLBs. MLBs and tubular myelin were seen in the lumens of future air spaces from day 20 onward. Nitrofen-exposed lungs differed from control lungs in that inclusion bodies (IBs) were less numerous in (low) cuboid alveolar cells on days 19 and 20, and more glycogen was seen on day 22. In addition intra- and extracellular "MLBs" in exposed lungs more often had an unusual appearance, i.e., a confluent structure and higher electron density. However, despite morphologic differences, there was no clear difference in phospholipid composition and SP-A content per mol phospholipid in bronchoalveolar lavage fluid. We conclude that morphologically hypoplastic lungs are less mature near term, without an apparent effect on surfactant composition.

Newborn surgical emergencies. Congenital diaphragmatic hernia and extracorporeal membrane oxygenation

Bochdalek hernia is a posterolateral defect in the embryogenesis of the diaphragm. Abdominal contents enter the thorax during fetal development and result in pulmonary hypoplasia. A cause of respiratory distress in the newborn, the management of this disease has undergone dramatic changes. The defect requires surgical repair, but success depends more on preoperative and postoperative management of the associated physiologic derangements.

Radiographic evidence of bronchopulmonary dysplasia in high-risk congenital diaphragmatic hernia survivors

Congenital diaphragmatic hernia is a congenital malformation associated with pulmonary hypoplasia. It often leads to respiratory failure, requiring artificial ventilation with high inflation pressures and high percentages of oxygen. We evaluated radiographic evidence of bronchopulmonary dysplasia (BPD) in survivors, who presented with respiratory distress within 6 hours after birth, by a radiographic scoring system measuring the severity of BPD by the Toce score and the degree of pulmonary hypoplasia by the Touloukian score. Fifteen of 45 survivors (33 percent) had clinical and radiological lung disease resembling BPD. As a group they had significantly higher Touloukian and Toce scores than survivors without BPD. Morbidity expressed as the duration of artificial ventilation, supplemental oxygen, and hospital stay was much higher in the BPD group. The hypoplastic lung in infants with congenital diaphragmatic hernia appears to be as susceptible to barotrauma and pulmonary oxygen toxicity as the lungs of prematurely born infants. To what extent BPD occurring in congenital diaphragmatic hernia survivors might influence the future development of lung function is not yet known.