Pulmonary neuroendocrine cells in nitrofen-induced diaphragmatic hernia and the effect of prenatal glucocorticoids

The high mortality associated with congenital diaphragmatic hernia (CDH) is due to pulmonary hypoplasia and hypertension, structural and functional abnormalities which can to some extent be ameliorated by prenatal administration of glucocorticoids. In the hypoplastic, hypertensive lungs of neonatal rats in which CDH has been induced by nitrofen, those pulmonary neuroendocrine cells (PNCs) containing calcitonin gene-related peptide (CGRP) increase in number, and it has been suggested that this might be due to inhibition of secretion of the peptide, the consequent decrease in its vasodilatory effects contributing to the hypertension. Whether this increase affects the entire population of PNCs, however, and how these cells are affected by administration of prenatal glucocorticoids, is unknown. As revealed by immunolabelling for protein gene product (PGP) 9.5, a general marker of NCs and expressed per cm² tissue section, the total PNC population in rats with nitrofen-induced CDH was significantly greater than in controls receiving only olive oil (672 vs 375/cm², P = 0.03) and was further increased (824 per cm²) in animals treated prenatally with dexamethasone (n = 8 in all groups). The increase in the total PNC population in rats with CDH is similar in magnitude to that described for the CGRP-containing subpopulation. Since the major role of the products of PNCs is now thought to be the regulation of development of pulmonary tissues and their response to injury, it is probable that the expansion of their population in the abnormal lungs associated with CDH is an adaptive response to pulmonary maldevelopment, a response possibly augmented by exogenous corticosteroids.     

Increased intracellular levels of calcitonin gene-related peptide-like immunoreactivity in pulmonary endocrine cells in an experimental model of congenital diaphragmatic hernia

A congenital diaphragmatic hernia (CDH) model was induced in pregnant rats following administration of 100 mg nitrofen. The fetuses were stored and fixed in Bouin's solution for 24 h after caesarean section at term. After fixation, the lungs were dissected out. Immunostaining of the CDH lungs and controls with rabbit anti-rat calcitonin gene-related peptide (CGRP) antibody at optimal and supraoptimal dilution levels was obtained by examining the intensity of staining with a series of dilutions of the antisera from 1: 1,000 to 1: 20,000. Supraoptimal dilution detects variations in antigen concentration that may be masked if the routine optimal dilution is used. Immunostaining of the lung by antisera to platelet-derived growth factor (PDGF) and alpha-smooth-muscle actin (ASMA) was performed to examine vascular remodelling. The number of CGRP-immunoreactive cells was significantly (P <0.001) greater in the lungs of CDH rats (n = 26) (0.74 +-0.19 NEB [neuroepithelial bodies]/mm²; mean +- SEM) compared with controls (n = 21) (0.30+-0.16 NEB/mm²) seen at supraoptimal dilution (1:20,000). Since CGRP is a vasodilator, this could have important implications in the development of pulmonary hypertension. The pattern of ASMA and PDGF immunostaining was similar in CDH lungs and controls, and therefore, vascular remodelling is not a feature of CDH lungs in fetuses delivered by caesarean section and not exposed to hypoxia.     

Perinatal management of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) retains high mortality due to lung hypoplasia and pulmonary hypertension. Efforts to improve survival and outcome have included fetal intervention, delivery at specialist centres, elective operation after stabilisation of labile physiology and minimising barotrauma. Permissive hypercapnea ('gentle ventilation') represents a significant advance in therapy gaining wider acceptance in centres worldwide. Human genetic studies are underway to identify candidate genes for the birth defect. Progress in the basic sciences may uncover critical aspects of developmental biology fundamental to CDH. Clinical trends in perinatal management of CDH are highlighted, which underpin the challenges of this lethal human anomaly.     

Management of pulmonary hypertension in congenital diaphragmatic hernia: nitric oxide with prostaglandin-E1 versus nitric oxide alone

Aim  Prostaglandin-E1 (PGE₁) is used at most centers for treating pulmonary hypertension (PH) in congenital diaphragmatic hernia (CDH) because it has been regarded as effective. The aim of this study was to investigate the role of PGE1 for treating PH in CDH. Methods  We reviewed 49 CDH cases with echocardiography-proven PH. PH was treated with PGE₁ and nitric oxide (NO) and high frequency oscillatory ventilation (HFOV) from 1997 to 2001 (PG + NO; n = 19) and with NO and HFOV from 2002 to 2007 (NO; n = 30). Results  Subject demographics, severity of PH, and presence of other anomalies were not significantly different between the two groups. In the PG + NO group, 12/19 (63.2%) survived (PG + NO-s) and 7/19 (36.8%) died (PG + NO-d). In the NO group, 21/30 (70.0%) survived (NO-s) and 9/30 (30.0%) died (NO-d). Survival rates were not significantly different. In the NO-s group, spontaneous closure of the ductus arteriosus (DA) was significantly earlier compared with the PG + NO-s group (P < 0.01; 4.0 ± 0.9 vs. 9.5 ± 2.2 days after birth). DA diameters were significantly larger in groups that died compared with groups that survived (P < 0.01), and PH persisted in groups that died. In the NO-s group, surgery was possible significantly earlier compared with the PG + NO-s group (P < 0.01; 3.75 ± 0.67 vs. 6.12 ± 0.78 days after birth). No NO-s case developed a PH crisis even though PGE₁ was not used. Hospital stay was significantly shorter in the NO-s group compared with the PG + NO-s group (P < 0.05; 39.9 ± 19 vs. 53.2 ± 23 days). Conclusion  Nitric oxide alone would appear to simplify the management of CDH with PH and provide better outcome.     

先天性膈疝继发新生儿持续肺动脉高压的研究进展

先天性膈疝(CDH)继发新生儿持续性肺动脉高压(PPHN)是新生儿高病死率的重要原因之一,是导致CDH 患儿生后出现呼吸、循环衰竭的重要因素。CDH 继发PPHN 的病情危重,治疗困难,治疗预后差,故针对阻止CDH 病理进程的产前干预已成为研究热点,尤其是关于阻断PPHN 形成过程的病因治疗。鉴于PPHN 的病因尚不明确,治疗效果差,该文以国内外相关研究为基础,综述CDH-PPHN 的发病机制与治疗研究进展,以期为相关研究与临床治疗提供参考     

Review shows that implementing a nationwide protocol for congenital diaphragmatic hernia was a key factor in reducing mortality and morbidity

The French Rare Disease Reference Center for congenital diaphragmatic hernia (CDH) was created in 2008, to implement a national protocol for foetuses and children with this serious condition. Neonatal mortality from CDH is 30‐40%, mainly due to pulmonary hypoplasia and persistent pulmonary hypertension, and half of those who live have high respiratory, nutritional and digestive morbidity. CDH management requires long‐term and specialised multidisciplinary care. It has been well established that a standardised management protocol improves the prognosis of children with CDH.

Conclusion

Organising health care and implementing a nationwide French protocol were key factors for reducing mortality and morbidity from CDH.     

Antenatal dexamethasone administration inhibits smooth-muscle-cell DNA synthesis in pulmonary-arterial media in nitrofen-induced congenital diaphragmatic hernia in rats

 The aim of this study was to investigate the effect of antenatal glucocorticoid therapy on smooth-muscle-cell (SMC) DNA synthesis in the pulmonary arteries (PA) in a nitrofen-induced congenital diaphragmatic hernia (CDH) rat model following nitrofen administration on day 9.5 of gestation. Antenatal dexamethasone (DEX) was given intraperitoneally on days 18.5 and 19.5 of gestation. Bromodeoxyuridine (BrdU) was injected via a jugular vein into the dam 1 h before the fetuses were killed by cesarean section at term. The fetuses were divided into three groups: group I (n = 10): normal controls; group II (n = 10): nitrofen-induced CDH; group III (n = 10): nitrofen-induced CDH with antenatal DEX treatment. Immunostaining of the lungs with anti-BrdU antibody was obtained by a standard avidin-biotin complex method. The number of immunopositive cells in the PA media and adventitia were counted using an image analyzer and analyzed statistically. The number of BrdU-immunopositive cells in the media was significantly increased in group II (16.83 ± 3.01) compared to groups I (9.16 ± 2.20) and III (6.83 ± 1.70) (P < 0.01). There was no significant difference between groups I and III. The number of BrdU-immunopositive cells in the adventitia was not significantly different between the three groups. Antenatal DEX treatment inhibits SMC DNA synthesis in PA media in CDH lungs. This may be a possible mechanism by which antenatal DEX prevents structural PA changes in nitrofen-induced CDH in rats. Accepted: 26 August 1999     

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.     

Aneurysmal dilatation of ductus arteriosus during lipo-prostaglandin E1 therapy for diaphragmatic hernia

We report a case of congenital diaphragmatic hernia in which aneurysmal dilatation of ductus arteriosus developed after lipo-prostaglandin E₁ (PGE₁) therapy for persistent fetal circulation. After surgery Lipo-PGE₁ was used at a dosage of 5 ng/kg per minute from days 2–9 during which aneurysmal dilatation (7 mm in diameter) developed and remained thereafter. Ductus arteriosus ligation was then performed. Lipo-PGE₁ may promote ductus arteriosus dilatation in cases of persistent fetal circulation.     

Endogenous nitric oxide and endothelin-1 in persistent pulmonary hypertension of the newborn

We studied changes in endogenous nitric oxide (NO) synthesis and endothelin-1 (ET-1) production in infants with persistent pulmonary hypertension of the newborn (PPHN). We determined concentrations of serum NO metabolites, i.e., nitrites and nitrates (NOx), and of plasma ET-1 in five infants with PPHN (PPHN group) and in 25 healthy full-term neonates (control group). In both groups, serum NOx concentrations increased over time and plasma ET-1 concentrations decreased with age. The differences in serum NOx concentrations between groups were not significant at <12 h and 24 h of age; however, they were significantly higher in the PPHN group than in the control group at 5 days of age. The differences in plasma ET-1 concentrations between groups were not significant at 5 days of age, but were significantly higher in the PPHN group than in the control group at <12 h and 24 h of age. Conclusion Limited endogenous nitric oxide synthesis and elevated endogenous endothelin-1 production during the first few days of life may contribute to pulmonary hypertension in infants with persistent pulmonary hypertension of the newborn. Received: 2 September 2000 / Accepted: 15 June 2000     

Sensory innervation of normal and hypospadiac prepuce: possible implications in hypospadiology

Sensory innervation of the skin influences wound healing through the release of neuropeptides from the nerve endings. The purpose of this study was to investigate the differences in the sensory innervation of the normal and the hypospadiac prepuce. The prepuce from 10 healthy children undergoing routine circumcision and 10 age-matched children undergoing hypospadias repair were submitted for immunohistochemistry, using antibodies against protein gene product (PGP) 9.5, calcitonin gene-related peptide (CGRP), and substance P (SP). The hypospadiac prepuce was found to be hypo-innervated for PGP 9.5 and CGRP positive nerves when compared with the normal prepuce (p<0.05). The number of SP-positive nerves were increased in the hypospadiac prepuce, but not to statistical significance (p=0.06, confidence interval >95%). There may be differences in the sensory innervation of the normal and hypospadiac prepuce. These differences in tissue environment may partly explain the postoperative edema, poor wound healing leading to urethrocutaneous fistula (UF), and increased analgesia requirements in patients undergoing hypospadias surgery.     

Neonatal extracorporeal life support: impact of new therapies on survival

OBJECTIVE: To evaluate the effects of pre-extracorporeal life support (ECLS) management with nitric oxide (NO), high frequency ventilation (HFV), and surfactant on mortality among neonates supported with ECLS. STUDY DESIGN: Extracorporeal Life Support Organization (ELSO) data on 7017 neonates cannulated for respiratory reasons between 1996 and 2003 were analyzed using chi2, analysis of variance, and logistic regression. RESULTS: The use of ECLS declined by 26.6% over the study period with no significant change in mortality. Unadjusted ECLS mortality for NO-treated patients was lower than for infants not treated with NO (25.1% vs 28.6%, P = .0012) and for infants treated with surfactant than for infants not treated with surfactant (18.7% vs 30.3%, p <.0001.) Unadjusted mortality for HFV-treated patients was no different than for non-HFV-treated patients (26.0% vs 26.6%, P = .56). After adjusting for confounders (primary diagnosis, age at cannulation, ECMO year 1996-1999 vs 2000-2003), surfactant use was associated with decreased mortality. NO-treated neonates were less likely to have a pre-ECLS cardiopulmonary arrest than infants not treated with NO. NO, HFV, and surfactant were not associated with prolongation of ECLS or mechanical ventilation. CONCLUSIONS: NO, HFV, and surfactant were not associated with increased mortality in neonates who require ECLS for hypoxic respiratory failure.