Hypertension In Congenital Diaphragmatic Hernia Research Articles

Effect of tadalafil on pulmonary hypoplasia in congenital diaphragmatic hernia of rat fetuses

Background. Pulmonary hypoplasia and persistent pulmonary hypertension in congenital diaphragmatic hernia are the cause of adverse perinatal outcomes. Dissatisfaction with the outcomes of intrauterine surgical correction of CDH determines the search for alternative non-surgical prenatal methods of treating pulmonary hypoplasia in CDH. Objective. To study the effect of a reversible selective inhibitor of specific phosphodiesterase type 5 (tadalafil) on the development of fetal lungs in rats in a model of congenital diaphragmatic hernia. Design and methods. An experimental study was conducted on the possibility of correcting fetal lung hypoplasia in rats when modeling a diaphragmatic hernia with nitrophen (100 mg orally, once on the 9th day of pregnancy). Results. Congenital diaphragmatic hernia was recorded in 12.5 % of offspring. Subcutaneous administration of tadalafil to pregnant rats (0,83 mg/kg, for 10 days, from the 9th day of pregnancy) in the lungs of fetuses increases the number of alveoli (by 22 % at p ≤ 0.05), the area of microvasculature vessels and the volume of lung parenchyma increases (by 1.25 % and 1.13 % more (at p ≤ 0.05)). Conclusion. The results obtained from the first experiment conducted in the Russian Federation to study the effect of tadalafil on the lungs in congenital diaphragmatic hernia of the fetus are comparable with the data of the authors who used sildenafil, however, the use of tadalafil seems more optimal due to the ease of its administration for potential practical use.

Arterial hypertension in infants with congenital diaphragmatic hernia following surgical repair

Pulmonary hypertension (PH) and cardiac dysfunction are established comorbidities of congenital diaphragmatic hernia (CDH). However, there is very little data focusing on arterial hypertension in CDH. This study aims to investigate the incidence of arterial hypertension in neonates with CDH at hospital discharge. Archived clinical data of 167 CDH infants who received surgical repair of the diaphragmatic defect and survived for > 60 days were retrospectively analyzed. Blood pressure (BP) values were averaged for the last 7 days before discharge and compared to standard BP values for sex, age, and height provided by the AHA in 2004. BP values reaching or extending the 95th percentile were defined as arterial hypertension. The use of antihypertensive medication was analyzed at discharge and during hospitalization. Arterial hypertension at discharge was observed in 19 of 167 infants (11.3%) of which 12 (63%) were not receiving antihypertensive medication. Eighty patients (47.9%) received antihypertensive medication at any point during hospitalization and 28.9% of 152 survivors (n = 44) received antihypertensive medication at discharge, although in 45.5% (n = 20) of patients receiving antihypertensive medication, the indication for antihypertensive medication was myocardial hypertrophy or frequency control. BP was significantly higher in ECMO compared to non-ECMO patients, despite a similar incidence of arterial hypertension in both groups (13.8% vs. 10.1%, p = 0.473). Non-isolated CDH, formula feeding, and minimal creatinine in the first week of life were significantly associated with arterial hypertension on univariate analysis. Following multivariate analysis, only minimal creatinine remained independently associated with arterial hypertension. Conclusion: This study demonstrates a moderately high incidence of arterial hypertension in CDH infants at discharge and an independent association of creatinine values with arterial hypertension. Physicians should be aware of this risk and include regular BP measurements and test of renal function in CDH care and follow-up.What is Known:• Due to decreasing mortality, morbidity is increasing in surviving CDH patients.• Pulmonary hypertension and cardiac dysfunction are well-known cardiovascular comorbidities of CDH.What is New:• There is a moderately high incidence of arterial hypertension in CDH infants at discharge even in a population with frequent treatment with antihypertensive medication.• A more complicated hospital course (ECMO, higher degree of PH, larger defect size) was associated with a higher risk for arterial hypertension.

Intra-amniotic sildenafil administration in rabbits: Safety, pharmacokinetics, organ distribution and histologic evaluation

BackgroundThe effectiveness of sildenafil in the management of pulmonary hypertension in congenital diaphragmatic hernia (CDH) has been reported but has not been systematically evaluated. Our studies have also demonstrated that intra-amniotic (IA) sildenafil administration improves pulmonary hypertension in CDH. MethodsWe evaluated the pharmacokinetics of sildenafil after IA administration in pregnant rabbits. Following maternal laparotomy, fetuses received IA injection of 0.8 mg of sildenafil. Maternal blood, amniotic fluid, and fetal tissues were collected at various time points. The concentrations of sildenafil and its major metabolite in samples were analyzed by liquid chromatography-mass spectrometry. To assess organ toxicity, 7 days after IA sildenafil administration, fetal organs were examined histologically. ResultsAfter IA dosing, sildenafil was absorbed quickly with an absorption half-life of 0.03–0.07 h into the fetal organs. All the organs showed a maximum concentration within 1 h and the disposition half-life ranged from 0.56 to 0.73 h. Most of the sildenafil was eliminated from both mothers and fetuses within 24 h after a single dose. There was no histological evidence of organ toxicity in the fetuses after a single dose of IA administration of sildenafil. ConclusionIA sildenafil is rapidly absorbed into the fetus, distributes into the mother, and is eliminated by the mother without accumulation or fetal organ toxicity. This study confirms the feasibility and the safety of IA administration of sildenafil and enables future applications in the treatment of CDH fetuses.

The heart in congenital diaphragmatic hernia: Knowns, unknowns, and future priorities

There is growing recognition that the heart is a key contributor to the pathophysiology of congenital diaphragmatic hernia (CDH), in conjunction with developmental abnormalities of the lung and pulmonary vasculature. Investigations to date have demonstrated altered fetal cardiac morphology, notably relative hypoplasia of the fetal left heart, as well as early postnatal right and left ventricular dysfunction which appears to be independently associated with adverse outcomes. However, many more unknowns remain, not least an understanding of the genetic and cellular basis for cardiac dysplasia and dysfunction in CDH, the relationship between fetal, postnatal and long-term cardiac function, and the impact on other parts of the body especially the developing brain. Consensus on how to measure and classify cardiac function and pulmonary hypertension in CDH is also required, potentially using both non-invasive imaging and biomarkers. This may allow routine assessment of the relative contribution of cardiac dysfunction to individual patient pathophysiological phenotype and enable better, individualized therapeutic strategies incorporating targeted use of fetal therapies, cardiac pharmacotherapies, and extra-corporeal membrane oxygenation (ECMO). Collaborative, multi-model approaches are now required to explore these unknowns and fully appreciate the role of the heart in CDH.

Prenatal Molecular Hydrogen Administration Ameliorates Several Findings in Nitrofen-Induced Congenital Diaphragmatic Hernia.

Oxidative stress plays a pathological role in pulmonary hypoplasia and pulmonary hypertension in congenital diaphragmatic hernia (CDH). This study investigated the effect of molecular hydrogen (H2), an antioxidant, on CDH pathology induced by nitrofen. Sprague-Dawley rats were divided into three groups: control, CDH, and CDH + hydrogen-rich water (HW). Pregnant dams of CDH + HW pups were orally administered HW from embryonic day 10 until parturition. Gasometric evaluation and histological, immunohistochemical, and real-time polymerase chain reaction analyses were performed. Gasometric results (pH, pO2, and pCO2 levels) were better in the CDH + HW group than in the CDH group. The CDH + HW group showed amelioration of alveolarization and pulmonary artery remodeling compared with the CDH group. Oxidative stress (8-hydroxy-2′-deoxyguanosine-positive-cell score) in the pulmonary arteries and mRNA levels of protein-containing pulmonary surfactant that protects against pulmonary collapse (surfactant protein A) were significantly attenuated in the CDH + HW group compared with the CDH group. Overall, prenatal H2 administration improved respiratory function by attenuating lung morphology and pulmonary artery thickening in CDH rat models. Thus, H2 administration in pregnant women with diagnosed fetal CDH might be a novel antenatal intervention strategy to reduce newborn mortality due to CDH.

Stereological Lung Parameters After Fetoscopic Abdominal Decompression of Congenital Diaphragmatic Hernia in an Ovine Model: A Pilot Study.

Background: Fetoscopic endoluminal tracheal occlusion (FETO) improves lung maturation in severe cases of congenital diaphragmatic hernia (CDH) but it does not ameliorate lung compression by herniated abdominal organs. Surgically opening the fetal abdomen (abdominal decompression [AD]) reduces the intrathoracic pressure by diverting the abdominal organs into the amniotic cavity-a probable causal therapy for lung hypoplasia and pulmonary hypertension in CDH. Open surgical abdominal decompression has been reported: we describe a minimally invasive approach in an ovine model of CDH as a probable fetoscopic intervention. Materials and Methods: Eight fetuses were included, 2 were kept as HEALTHY controls. A CDH (left side, liver down) was created by open fetal surgery at midgestation in 6 fetuses, 2 were taken as CDH controls. Fetoscopic abdominal decompression (fAD) was performed 21 days later in 4 animals. The fetuses were retrieved at the end of gestation and evaluated by lung stereology. Results: fAD led to a near total evacuation of the thoracic cavity in 2 of the 4 animals. Fetuses with CDH had a lower total volume and fraction of alveolar air space, a lower volume fraction of the parenchyma, and an increase of the volume fraction of the alveolar septa and atelectasis, as well as an increased mean thickness of alveolar septa compared with HEALTHY fetuses. Fetuses treated with abdominal decompression showed an improvement of stereological parameters. Conclusions: In spite of relevant limitations (pilot study, small groups, spontaneous closure of the abdominal incision) we were able to demonstrate that abdominal decompression for CDH can be performed by fetoscopy. Our results support the hypothesis of causally improving lung development by abdominal decompression, thus implying increased survival in extreme cases of CDH. A refinement of the fetoscopic techniques and direct comparison to FETO appears warranted.

Opposing Effects of TGFβ 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 β (TGFβ) 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 TGFβ 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.

Emerging antenatal therapies for congenital diaphragmatic hernia-induced pulmonary hypertension in preclinical models.

Congenital diaphragmatic hernia (CDH)-related deaths are the largest contributor of in-hospital neonatal deaths in children with congenital malformations. Morbidity and mortality in CDH are directly related to the development of pulmonary hypertension (PH). Current treatment consists of supportive measures. To date, no pharmacotherapy has been shown to effectively reverse the hallmark finding of pulmonary vascular remodeling that is associated with pulmonary hypertension in CDH (CDH-PH). As such, there is a great need for novel therapies to effectively manage CDH-PH. Our review aims to evaluate emerging therapies, and specifically focuses on those that are still under investigation and not approved for clinical use by the Food and Drug Administration. Therapies were categorized into antenatal pharmacotherapies or antenatal regenerative therapies and assessed on their method of administration, safety profile, effect on pulmonary vascular pathophysiology, and overall efficacy. In general, emerging antenatal pharmaceutical and regenerative treatments primarily aim to alleviate pulmonary vascular remodeling by restoring normal function and levels of key regulatory factors involved in pulmonary vascular development and/or in promoting angiogenesis. Overall, while these emerging therapies show great promise for the management of CDH-PH, most require further assessment of safety and efficacy in preclinical models before translation into the clinical setting.

Overexpression of YAP and miR-130a is closely related to pulmonary hypertension in congenital diaphragmatic hernia

Purpose: The aim of this study was to investigate the expression of YAP and miR-130a in the normal lung tissues and CDH lung tissues through the rat model of CDH, and preliminarily explored the relationship between YAP, miR-130a and CDH. Methods: Pregnant rats were divided into two groups: control (n = 5) and CDH (n = 5). A single oral dose (125 mg/kg) of nitrofen was administered to pregnant rats on embryonic day (E) 9.5 to induce CDH. All fetuses were acquired by cesarean delivery on E21.5. Fetuses with diaphragmatic hernias in the CDH groups were chosen for analysis. Lung weight (LW) and body weight (BW) were recorded and histologic evaluations, image analysis, western blot analysis and PCR were performed after lung processing. Results: Five female rats in the control group produced 76 fetuses without CDH. CDH was observed in 49 of 72 rat fetuses in the CDH group. Pulmonary hypoplasia and vascular remodeling were observed in the CDH group. YAP expression in the lungs was markedly increased in the CDH group compared to the control group (P = 0.001). However, there was no significant difference in the phosphorylation level of YAP (P = 0.113) between the two group. YAP mRNA and miR-130a expression in the lungs were markedly increased in the CDH group compared to the control group (P = 0.01, P = 0.002). Conclusion: A relative increase YAP activity and miR-130a expression in the CDH rats may be associated with increased pulmonary vascular resistance. The role of the feedback mechanism between YAP and miR-130a playing in the CDH-associated pulmonary hypertension deserves further study.

Use of prostaglandin E1 to treat pulmonary hypertension in congenital diaphragmatic hernia

Background/PurposeProstaglandin E1 (PGE) has been used to maintain ductus arteriosus patency and unload the suprasystemic right ventricle (RV) in neonates with congenital diaphragmatic hernia (CDH) and severe pulmonary hypertension (PH). Here we evaluate the PH response in neonates with CDH and severe PH treated with PGE. MethodsWe performed a retrospective chart review of CDH infants treated at our center between 2011 and 2016. In a subset, PGE was initiated for echocardiographic evidence of severe PH, metabolic acidosis, or hypoxemia. To assess PH response, we evaluated laboratory data, including B-type natriuretic peptide (BNP) and echocardiograms before and after PGE treatment. Categorical and continuous data were analyzed with Fisher's exact tests and Mann–Whitney t-tests, respectively. ResultsFifty-seven infants were treated with PGE a mean 17 ± 2 days. BNP levels declined after 1.4 ± 0.2 days of treatment and again after 5.2 ± 0.6 days. After 6 ± 0.8 days of treatment, echocardiographic estimates of severe PH by tricuspid regurgitation jet velocity, ductus arteriosus direction, and ventricular septum position also improved significantly. Treatment was not associated with postductal hypoxemia or systemic hypoperfusion. ConclusionsIn patients with CDH and severe PH, PGE is well tolerated and associated with improved BNP and echocardiographic indices of PH, suggesting successful unloading of the RV. Type of studyTreatment study. Level of evidenceLevel III.

Antenatal sildenafil administration to prevent pulmonary hypertension in congenital diaphragmatic hernia (SToP-PH): study protocol for a phase I/IIb placenta transfer and safety study

BackgroundCongenital diaphragmatic hernia is an orphan disease with high neonatal mortality and significant morbidity. An important cause for this is pulmonary hypertension, for which no effective postnatal therapy is available to date. An innovative strategy aiming at treating or preventing pulmonary hypertension more effectively is urgently needed. Prenatal sildenafil administration to expectant mothers prevented fetal and neonatal vascular changes leading to pulmonary hypertension in several animal models, and is, therefore, a promising approach. Before transferring this antenatal medical approach to the clinic, more information is needed on transplacental transfer and safety of sildenafil in humans.MethodsThis is a randomized, investigator-blinded, double-armed, parallel-group, phase I/IIb study with as a primary objective to measure the in-vivo transplacental transfer of sildenafil in women in the second and early third trimester of pregnancy (sub-study 1; weeks: 20.0–32.6) and at term (sub-study 2; weeks: 36.6–40). Participants will be randomized to two different sildenafil doses: 25 or 75 mg. In sub-study 1, a single dose of the investigational product will be administered to women undergoing termination of pregnancy, and maternal and fetal blood samples will be collected for determination of sildenafil concentrations. In sub-study 2, sildenafil will be administered three times daily from 3 days before planned delivery until actual delivery, following which maternal and umbilical cord samples will be collected. Proxies of maternal and fetal tolerance as well as markers of fetal pulmonary vasodilation will also be measured.DiscussionThis is the first study evaluating in-vivo transplacental passage of sildenafil in humans.Trial registrationEU Clinical Trials Register 2016–002619-17, validated on 12 August 2016.Trial sponsor: UZ Leuven, Herestraat 49, 3000 Leuven.

Cardiac dysfunction in congenital diaphragmatic hernia: Pathophysiology, clinical assessment, and management

Cardiac dysfunction is an important consequence of pulmonary hypertension in congenital diaphragmatic hernia and a determinant of disease severity. Increased afterload leads to right ventricular dilatation and diastolic dysfunction. Septal displacement and dysfunction impair left ventricular function, which may also be compromised by fetal hypoplasia. Biventricular failure contributes to systemic hypotension and hypoperfusion. Early and regular echocardiographic assessment of cardiac function and pulmonary artery pressure can guide therapeutic decision-making, including choice and timing of pulmonary vasodilators, cardiotropes, ECMO, and surgery.

Outcomes of congenital diaphragmatic hernia repair on extracorporeal life support.

Extracorporeal life support (ECLS) is applied to refractory pulmonary hypertension in congenital diaphragmatic hernia (CDH). We evaluate the single-center outcomes of infants with CDH to determine the utility of late repair on ECLS versus repair post-decannulation. Records of infants with CDH (2004-2014) were retrospectively reviewed. CDH was diagnosed in 177 infants. Sixty six (37%) underwent ECLS, of which, 11 died prior to repair, 33 were repaired post-decannulation, and 22 were repaired on ECLS. Repair was delayed in patients on ECLS (19 versus 10days, p<0.001). Patients repaired on ECLS had longer ECLS runs (22 versus 12days, p<0.001) and higher rates of bleeding and mortality than those repaired post-decannulation. Survival was 54% in infants undergoing ECLS, 65% in those who underwent repair, 36% in those repaired during ECLS, and 85% in those who were decannulated prior to repair. Eighteen percent (N=4) of deaths after repair on ECLS were attributable to surgical bleeding. The remainder was due to pulmonary hypertension or sepsis. Infants who underwent CDH repair post-decannulation had excellent outcomes and no mortalities attributable to repair. Neonates who underwent repair on ECLS late on bypass had the lowest survival rate with only 18% of mortality in this cohort attributable to surgical bleeding.

Fetal ultrasound markers of severity predict resolution of pulmonary hypertension in congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) results in morbidity and death from lung hypoplasia and persistent pulmonary hypertension (PH). We sought to define the relationship between fetal ultrasound markers of severity in CDH and the time to resolution of neonatal PH. We conducted a retrospective study of fetuses with an antenatal ultrasound scan and left-sided CDH cared for at the University of California San Francisco (2002-2012). Fetal liver position was classified on ultrasound scan as abdominal (entire liver within the abdomen) or thoracic (any portion of the liver within the thorax). Fetal stomach position was classified from least to most aberrant: abdominal, anterior left chest, mid-posterior left chest, or retrocardiac (right chest). Lung-to-head ratio (LHR) was determined from available scans at 20-29 weeks of gestational age (GA). Routine neonatal echocardiograms were performed weekly for up to 6 weeks or until PH resolved or until discharge. PH was assessed by echocardiogram with the use of a hierarchy of ductus arteriosus level shunt, interventricular septal position, and tricuspid regurgitant jet velocity. Days to PH-free survival was defined as the age at which pulmonary artery pressure was estimated to be <2/3 systemic blood pressure. Cox proportional hazards models adjusted for GA at birth, era of birth, fetal surgery, and GA at ultrasound scan (LHR model only), with censoring at 100 days. Of 118 patients, the following fetal markers were available: LHR (n = 53), liver position (n = 112), and stomach position (n = 80). Fewer infants experienced resolved PH if they had LHR <1 (P = .006), thoracic liver position (P = .001), or more aberrant stomach position (P < .001). There was also a decreased rate of resolution of PH in infants with LHR <1 (hazard ratio, 0.30; P = .007), thoracic liver position (hazard ratio, 0.38; P < .001), and more aberrant stomach position (hazard ratios, 0.28 [P = .002]; 0.1 [P < .001]; and 0.07 [P < .001]). Fetal ultrasound markers of CDH severity are predictive not only of death but also of significant morbidity. LHR <1, thoracic liver, and aberrant stomach position are associated with delayed time to resolution of PH in infants with CDH and may be used to identify fetuses at high risk of persistent PH.

Early neonatal echocardiographic findings in an experimental rabbit model of congenital diaphragmatic hernia.

This study aimed to demonstrate that congenital diaphragmatic hernia (CDH) results in vascular abnormalities that are directly associated with the severity of pulmonary hypoplasia and hypertension. These events increase right ventricle (RV) afterload and may adversely affect disease management and patient survival. Our objective was to investigate cardiac function, specifically right ventricular changes, immediately after birth and relate them to myocardial histological findings in a CDH model. Pregnant New Zealand rabbits underwent the surgical procedure at 25 days of gestation (n=14). CDH was created in one fetus per horn (n=16), and the other fetuses were used as controls (n=20). At term (30 days), fetuses were removed, immediately dried and weighed before undergoing four-parameter echocardiography. The lungs and the heart were removed, weighed, and histologically analyzed. CDH animals had smaller total lung weight (P<0.005), left lung weight (P<0.005), and lung-to-body ratio (P<0.005). Echocardiography revealed a smaller left-to-right ventricle ratio (LV/RV, P<0.005) and larger diastolic right ventricle size (DRVS, P<0.007). Histologic analysis revealed a larger number of myocytes undergoing mitotic division (186 vs 132, P<0.05) in CDH hearts. Immediate RV dilation of CDH hearts is related to myocyte mitosis increase. This information may aid the design of future strategies to address pulmonary hypertension in CDH.

Effect of corticosteroids and lung ventilation in the VEGF and NO pathways in congenital diaphragmatic hernia in rats.

The use of dexamethasone (Dx) stimulates growth, fetal lung maturation and can improve pulmonary hypertension in congenital diaphragmatic hernia (CDH). Our aim was to evaluate the effect of Dx on the lung after fetal pulmonary ventilation in the CDH rat model. Some groups underwent prenatal treatment with dexamethasone (0.4mg/kg) that was given at 18.5 gestational day (GD). Sprague-Dawley rat fetuses were divided into groups: control (C); ventilated control (CV); control exposed to dexamethasone (CDx); ventilated control exposed to dexamethasone (CVDx); congenital diaphragmatic hernia (CDH), ventilated CDH (CDHV), CDH exposed to dexamethasone (CDHDx) and ventilated CDH exposed to dexamethasone (CDHVDx). At 21.5 GD fetuses were delivered by C-section, weighed and ventilated for 30min. We analyzed the lung morphometry by Masson's Trichrome stain, and VEGF, VEGFR1, VEGFR2 and NOS3 expression by immunohistochemistry. All fetuses with CDH, with or without prenatal dexamethasone showed lung and body weight lower than control fetuses (p<0.05). All groups that received dexamethasone showed a decrease in the medial muscular layer of arterioles, the internal diameter of the air spaces (Lma) and length of parenchymal transection/airspace ratio (p<0.05). In the immunohistochemistry, VEGF decreased more in CDHDV group (p<0.05). VEGFR1 showed no difference, whereas VEGFR2 decreased significantly in the CDHDV group (p<0.05). NOS3 increased in the group CDHDV (p<0.05). The use of prenatal dexamethasone added to ventilation alters the VEGF and NO pathways.

Sildenafil in Use for Treatment of Pulmonary Hypertension in Congenital Diaphragmatic Hernia: Short Literature Review

Congenital Diaphragmatic Hernia (CDH) is a complex malformation in the newborn baby. The management, either surgical or non-surgical is an ongoing challenge. Especially in regard to the question how to treat the concomitant pulmonary hypertension best. Here sildenafil, more commonly known in the public as Viagra® and for the treatment of erectile dysfunction seems to have beneficial effects in pulmonary hypertension treatment of CDH patients as well. Thus, this short review aims to evaluate the actual literature for current evidence and practical application.

Fetal production of growth factors and inflammatory mediators predicts pulmonary hypertension in congenital diaphragmatic hernia

BackgroundCongenital diaphragmatic hernia (CDH) represents a spectrum of lung hypoplasia and consequent pulmonary hypertension is an important cause of postnatal morbidity and mortality. We studied biomarkers at the maternal-fetal interface to understand factors associated with the persistence of pulmonary hypertension.MethodsMaternal and cord blood samples from fetuses with CDH and unaffected controls were analyzed using a human 39plex immunoassay kit. Cellular trafficking between the mother and the fetu was quantified using quantitative real-time PCR for non-shared alleles. Biomarker profiles were then correlated with CDH severity based on the degree of pulmonary hypertension.ResultsCord blood levels of epidermal growth factor, platelet-derived growth factor, and several inflammatory mediators increased significantly as the severity of CDH increased, while maternal levels growth factors and mediators decreased significantly with CDH severity. Maternal cells were increased in fetuses with severe CDH compared to controls, with elevated levels of the chemokine CXCL-10 in patients with the highest trafficking.ConclusionPatients with CDH demonstrate pro-inflammatory and chemotactic signals in fetal blood at the time of birth. Since some of these molecules have been implicated in the development of pulmonary hypertension, prenatal strategies targeting specific molecular pathways may be useful adjuncts to current fetal therapies.

Increased activation of NADPH oxidase 4 in the pulmonary vasculature in experimental diaphragmatic hernia

Persistent pulmonary hypertension remains a major cause of mortality and morbidity in congenital diaphragmatic hernia (CDH). NADPH oxidases (Nox) are the main source of superoxide production in vasculature. Nox4 is highly expressed in the smooth muscle and endothelial cells of the vascular wall and increased activity has been reported in the pulmonary vasculature of both experimental and human pulmonary hypertension. Peroxisome proliferator-activated receptor (PPARγ) is a key regulator of Nox4 expression. Targeted depletion of PPARγ results in pulmonary hypertension phenotype whereas activation of PPARγ attenuates pulmonary hypertension and reduces Nox4 production. The nitrofen-induced CDH model is an established model to study the pathogenesis of pulmonary hypertension in CDH. It has been previously reported that PPARγ-signaling is disrupted during late gestation and H(2)O(2) production is increased in nitrofen-induced CDH. We designed this study to investigate the hypothesis that Nox4 expression and activation is increased and vascular PPARγ is decreased in nitrofen-induced CDH. Pregnant rats were treated with either nitrofen or vehicle on gestational day 9 (D9). Fetuses were sacrificed on D21 and divided into control and CDH. RT-PCR, western blotting and confocal-immunofluorescence-double-staining were performed to determine pulmonary expression levels of PPARγ, Nox4 and Nox4-activation (p22(phox)). There was a marked increase in medial and adventitial thickness in pulmonary arteries of all sizes in CDH compared to controls. Pulmonary Nox4 levels were significantly increased whereas PPARγ levels were decreased in nitrofen-induced CDH compared to controls. Western blotting revealed increased pulmonary protein expression of the Nox4-activating subunit p22(phox) and decreased protein expression of PPARγ in CDH compared to controls. Confocal-microscopy confirmed markedly increased pulmonary expression of the Nox4 activating subunit p22(phox) accompanied by decreased perivascular PPARγ expression in lungs of nitrofen-exposed fetuses compared to controls. To our knowledge, the present study is the first to report increased Nox4 production in the pulmonary vasculature of nitrofen-induced CDH. Down-regulation of the PPARγ-signaling pathway may lead to increased superoxide production, resulting in pulmonary vascular dysfunction and contributing to pulmonary hypertension in the nitrofen-induced CDH model. PPARγ-activation inhibiting Nox4 production may therefore represent a potential therapeutic approach for the treatment of pulmonary hypertension in CDH.

Prenatal retinoic acid improves lung vascularization and VEGF expression in CDH rat

We sought to investigate the effects of antenatal retinoic acid on the pulmonary vasculature and vascular endothelial growth factor (VEGF) and VEGF receptors (VEGFR) expression in a nitrofen-induced congenital diaphragmatic hernia (CDH) model. Rat fetuses were exposed to nitrofen at gestational day 9.5 and/or all-trans retinoic acid (ATRA) at gestational days 18.5-20.5. We assessed lung growth, airway, and vascular morphometry. VEGF, VEGFR1, and VEGFR2 expression was analyzed by Western blotting and immunohistochemistry. Continuous data were analyzed by analysis of variance and Kruskal-Wallis test. CDH decreased lung to body weight ratio, increased mean linear intercept and mean transection length/airspace, and decreased mean airspace cord length. ATRA did not affect lung growth or morphometry. CDH increased proportional medial wall thickness of arterioles while ATRA reduced it. ATRA recovered expression of VEGF and receptors, which were reduced in CDH. Retinoic acid and VEGF may provide pathways for preventing pulmonary hypertension in CDH.