Opposing Effects of TGFß and BMP in the Pulmonary Vasculature in Congenital Diaphragmatic Hernia.

Background: Pulmonary hypertension is the major cause of morbidity and mortality in congenital diaphragmatic hernia (CDH). Mutations in several genes that encode signaling molecules of the transforming growth factor ß (TGFß) and bone morphogenetic protein (BMP) pathways have previously been associated with CDH. Since studies on the activation of these pathways in CDH are scarce, and have yielded inconsistent conclusions, the downstream activity of both pathways was assessed in the nitrofen-CDH rat model. Methods and Results: Pregnant Sprague-Dawley rats were treated with nitrofen at embryonic day (E) 9.5 to induce CDH in offspring. At E21, lungs were screened for the expression of key factors of both signaling pathways, at both the mRNA transcript and protein levels. Subsequently, paying particular attention to the pulmonary vasculature, increased phosphorylation of SMAD2, and decreased phosphorylation of Smad5 was noted in the muscular walls of small pulmonary vessels, by immunohistochemistry. This was accompanied by increased proliferation of constituent cells of the smooth muscle layer of these vessels. Conclusions: Increased activation of the TGFß pathway and decreased activation of the BMP pathway in the pulmonary vasculature of rats with experimentally-induced CDH, suggesting that the deregulated of these important signaling pathways may underlie the development of pulmonary hypertension in CDH.

Treatment of rat congenital diaphragmatic hernia with sildenafil and NS-304, selexipag's active compound, at the pseudoglandular stage improves lung vasculature.

Patients with congenital diaphragmatic hernia (CDH) often suffer from severe pulmonary hypertension, and the choice of current vasodilator therapy is mostly based on trial and error. Because pulmonary vascular abnormalities are already present early during development, we performed a study to modulate these pulmonary vascular changes at an early stage during gestation. Pregnant Sprague-Dawley rats were treated with nitrofen at day 9.5 of gestation (E9.5) to induce CDH in the offspring, and subsequently, the phosphodiesterase-5 inhibitor sildenafil and/or the novel prostaglandin-I receptor agonist selexipag (active compound NS-304) were administered from E17.5 until E20.5. The clinical relevant start of the treatment corresponds to week 20 of gestation in humans, when CDH is usually detected by ultrasound. CDH pups showed increased density of air saccules that was reverted after the use of only sildenafil. The pulmonary vascular wall was thickened, and right ventricular hypertrophy was present in the CDH group and improved both after single treatment with sildenafil or selexipag, whereas the combination therapy with both compounds did not have additive value. In conclusion, antenatal treatment with sildenafil improved airway morphogenesis and pulmonary vascular development, whereas selexipag only acted positively on pulmonary vascular development. The combination of both compounds did not act synergistically, probably because of a decreased efficiency of both compounds caused by cytochrome- P450 3A4 interaction and induction. These new insights create important possibilities for future treatment of pulmonary vascular abnormalities in CDH patients already in the antenatal period of life.

Pulmonary vascular development in congenital diaphragmatic hernia.

Congenital diaphragmatic hernia (CDH) is a rare congenital anomaly characterised by a diaphragmatic defect, persistent pulmonary hypertension (PH) and lung hypoplasia. The relative contribution of these three elements can vary considerably in individual patients. Most affected children suffer primarily from the associated PH, for which the therapeutic modalities are limited and frequently not evidence based. The vascular defects associated with PH, which is characterised by increased muscularisation of arterioles and capillaries, start to develop early in gestation. Pulmonary vascular development is integrated with the development of the airway epithelium. Although our knowledge is still incomplete, the processes involved in the growth and expansion of the vasculature are beginning to be unravelled. It is clear that early disturbances of this process lead to major pulmonary growth abnormalities, resulting in serious clinical challenges and in many cases death in the newborn. Here we provide an overview of the current molecular pathways involved in pulmonary vascular development. Moreover, we describe the abnormalities associated with CDH and the potential therapeutic approaches for this severe abnormality.

Changes in vasoactive pathways in congenital diaphragmatic hernia associated pulmonary hypertension explain unresponsiveness to pharmacotherapy.

BACKGROUND: Patients with congenital diaphragmatic hernia (CDH) have structural and functional different pulmonary vessels, leading to pulmonary hypertension. They often fail to respond to standard vasodilator therapy targeting the major vasoactive pathways, causing a high morbidity and mortality. We analyzed whether the expression of crucial members of these vasoactive pathways could explain the lack of responsiveness to therapy in CDH patients. METHODS: The expression of direct targets of current vasodilator therapy in the endothelin and prostacyclin pathway was analyzed in human lung specimens of control and CDH patients. RESULTS: CDH lungs showed increased expression of both ETA and ETB endothelin receptors and the rate-limiting Endothelin Converting Enzyme (ECE-1), and a decreased expression of the prostaglandin-I2 receptor (PTGIR). These data were supported by increased expression of both endothelin receptors and ECE-1, endothelial nitric oxide synthase and PTGIR in the well-established nitrofen-CDH rodent model. CONCLUSIONS: Together, these data demonstrate aberrant expression of targeted receptors in the endothelin and prostacyclin pathway in CDH already early during development. The analysis of this unique patient material may explain why a significant number of patients do not respond to vasodilator therapy. This knowledge could have important implications for the choice of drugs and the design of future clinical trials internationally.

Attenuated PDGF signaling drives alveolar and microvascular defects in neonatal chronic lung disease.

Neonatal chronic lung disease (nCLD) affects a significant number of neonates receiving mechanical ventilation with oxygen-rich gas (MV-O2). Regardless, the primary molecular driver of the disease remains elusive. We discover significant enrichment for SNPs in the PDGF-Rα gene in preterms with nCLD and directly test the effect of PDGF-Rα haploinsufficiency on the development of nCLD using a preclinical mouse model of MV-O2 In the context of MV-O2, attenuated PDGF signaling independently contributes to defective septation and endothelial cell apoptosis stemming from a PDGF-Rα-dependent reduction in lung VEGF-A. TGF-ß contributes to the PDGF-Rα-dependent decrease in myofibroblast function. Remarkably, endotracheal treatment with exogenous PDGF-A rescues both the lung defects in haploinsufficient mice undergoing MV-O2 Overall, our results establish attenuated PDGF signaling as an important driver of nCLD pathology with provision of PDGF-A as a protective strategy for newborns undergoing MV-O2.

Congenital Diaphragmatic Hernia and Growth to 12 Years.

OBJECTIVES: Growth problems are reported in patients with congenital diaphragmatic hernia during the first years of life. However, it is unknown if poor growth persists during childhood. We therefore evaluated growth of patients longitudinally until 12 years of age. METHODS: This prospective study included 172 patients (43 treated with extracorporeal membrane oxygenation [ECMO]) born from 1999 to 2014. Z scores of height-for-age (HFA), weight-for-height, and distance-to-target height were calculated at 6 months of age and at 1, 2, 5, 8, and 12 years of age. Data were analyzed by using general linear models. RESULTS: At 1 year of age, the mean weight-for-height z score had declined in ECMO (-1.30, 95% confidence interval: -1.62 to -0.97) and non-ECMO patients (-0.72, 95% confidence interval: -0.91 to -0.54; P < .05). Thereafter in ECMO patients, the mean HFA z score deteriorated between 1 (-0.43, 95% confidence interval: -0.73 to -0.13) and 5 years of age (-1.08, 95% confidence interval: -1.38 to -0.78; P < .01). In non-ECMO patients, the mean HFA z score deteriorated between 2 (-0.35, 95% confidence interval: -0.53 to -0.17) and 5 years of age (-0.56, 95% confidence interval: -0.75 to -0.37; P = .002). At 12 years of age, the mean HFA z score was still less than the norm in both groups: ECMO (-0.67, 95% confidence interval: -1.01 to -0.33) versus non-ECMO (-0.49, 95% confidence interval: -0.77 to -0.20; P < .01). Adjusting for target height improved the mean height z scores but did not bring them to normal range. CONCLUSIONS: Poor linear growth persisted at 12 years of age. The pattern of early deterioration of weight gain followed by a decline in linear growth is suggestive of inadequate nutrition during infancy. Therefore, nutritional assessment and intervention should be started early and should be continued during childhood.

Clinically relevant timing of antenatal sildenafil treatment reduces pulmonary vascular remodeling in congenital diaphragmatic hernia.

Patients with congenital diaphragmatic hernia (CDH) suffer from severe pulmonary hypertension attributable to altered development of the pulmonary vasculature, which is often resistant to vasodilator therapy. Present treatment starts postnatally even though significant differences in the pulmonary vasculature are already present early during pregnancy. We examined the effects of prenatal treatment with the phosphodiesterase-5 inhibitor sildenafil on pulmonary vascular development in experimental CDH starting at a clinically relevant time. The well-established, nitrofen-induced CDH rodent model was treated daily with 100 mg/kg sildenafil from day 17.5 until day 20.5 of gestation (E17.5-20.5). Importantly, this timing perfectly corresponds to the developmental stage of the lung at 20 wk of human gestation, when CDH is detectable by 2D-ultrasonography and/or MRI. At E21.5 pups were delivered by caesarean section and euthanized by lethal injection of pentobarbital. The lungs were isolated and subsequently analyzed using immunostaining, real-time PCR, and volume measurements. Prenatal treatment with sildenafil improved lung morphology and attenuated vascular remodeling with reduced muscularization of the smaller vessels. Pulmonary vascular volume was not affected by sildenafil treatment. We show that prenatal treatment with sildenafil within a clinically relevant period improves pulmonary vascular development in an experimental CDH model. This may have important implications for the management of this disease and related pulmonary vascular diseases in human.

Increased incidence of hypertrophic pyloric stenosis in esophageal atresia patients.

INTRODUCTION: Around half of patients with esophageal atresia (EA) have additional congenital anomalies. Hypertrophic pyloric stenosis (HPS) in these patients is less known, with only 36 cases reported in the past literature. This retrospective study aimed to establish the incidence and clinical presentation of EA patients in combination with HPS in our hospital. MATERIALS AND METHODS: A retrospective study was based on the medical histories from all patients with EA who underwent surgical repair in our hospital from 1988 through 2012. RESULTS: Of 267 patients with EA, 20 also developed HPS (7.5%). The latter group showed male predominance, 90 versus 60% in the EA without HPS group. The first symptoms of HPS were mostly vomiting and/or feeding intolerance (n = 19). The diagnosis was mostly delayed, with a median of 6 days (range, 1-21 days). CONCLUSIONS: This is the first report on the high incidence of HPS in a large series of EA patients. The incidence found is 30 times higher than that in the normal population. HPS should be considered when patients show recurrent or persisting vomiting and feeding intolerance after surgery. The reason for the higher incidence should be further investigated.