Development Of Congenital Diaphragmatic Hernia Research Articles

Bias in the prenatal lung measurements in fetal congenital diaphragmatic hernia with intrauterine growth restriction.

The failure of a fetus to develop to its full potential due to maternal or placental factors is known as intrauterine growth restriction (IUGR). Fetal head growth is usually preserved in that situation producing a potential discordance between head and body size. Our goal is to discover if IUGR has an impact on the prenatal ultrasound measurements taken to assess pulmonary development in congenital diaphragmatic hernia (CDH). A retrospective chart review (IRB#2017-6361) was performed on all prenatally diagnosed CDH patients from 2007 to 2016. Patient demographics, fetal and neonatal anthropometric measurements, and fetal lung parameters were the main subjects of the data that were gathered. Fetal growth was assessed by the curves based on US data by Olsen etal. and by Peleg etal. Of 147 CDH patients, 19 (12.9 %) patients were diagnosed with IUGR before the 30th gestational week while there were 20 (13.6 %) patients after the 30th gestational week. Patients with IUGR and the observed-to-expected lung-to-head ratio (O/E LHR) less than 25 % had better survival rates both to discharge and date compared to non IUGR group (p=0.226, OR 2.25 95 % CI 0.60-1.08 and p=0.175, OR 2.40 95 % CI 0.66-1.17, respectively). Moreover, the ECMO need of the patients who had IUGR and O/E LHR less than 25 % was significantly less than the patients without IUGR (38.5 vs. 80.0 %, p=0.005). This study confirms that the intrauterine measurements to predict pulmonary hypoplasia in CDH patients are misleading in the presence of IUGR and cause an overestimation.

Pulmonary vasculature development in congenital diaphragmatic hernia: a novel automated quantitative imaging analysis.

Impaired fetal lung vasculature determines the degree of pulmonary hypertension in the congenital diaphragmatic hernia (CDH). This study aims to demonstrate the morphometric measurements that differ in pulmonary vessels of fetuses with CDH. Nitrofen-induced CDH Sprague-Dawley rat fetuses were scanned with microcomputed tomography. The analysis of the pulmonary vascular tree was performed with artificial intelligence. The number of segments in CDH was significantly lower than that in the control group on the left (U = 2.5, p = 0.004) and right (U = 0, p = 0.001) sides for order 1(O1), whereas there was a significant difference only on the right side for O2 and O3. The pooled element numbers in the control group obeyed Horton's law (R2 = 0.996 left and R2 = 0.811 right lungs), while the CDH group broke it. Connectivity matrices showed that the average number of elements of O1 springing from elements of O1 on the left side and the number of elements of O1 springing from elements of O3 on the right side were significantly lower in CDH samples. According to these findings, CDH not only reduced the amount of small order elements, but also destroyed the fractal structure of the pulmonary arterial trees.

Overactivated Epithelial NF-κB Disrupts Lung Development in Congenital Diaphragmatic Hernia.

Abnormal lung development is the main cause of morbidity and mortality in neonates with congenital diaphragmatic hernia (CDH), a common birth defect (1:2500) of largely unknown pathobiology. Recent studies discovered that inflammatory processes, and specifically NF-κB associated pathways are enriched in human and experimental CDH. However, the molecular signaling of NF-κB in abnormal CDH lung development and its potential as a therapeutic target requires further investigation. Using sections and hypoplastic lung explant cultures from the nitrofen rat model of CDH and human fetal CDH lungs, we demonstrate that NF-κB and its downstream transcriptional targets are hyperactive during abnormal lung formation in CDH. NF-κB activity was especially elevated in the airway epithelium of nitrofen and human CDH lungs at different developmental stages. Fetal rat lung explants had impaired pseudoglandular airway branching after exposure to nitrofen, together with increased phosphorylation and transcriptional activity of NF-κB. Dexamethasone, the broad and clinically applicable anti-inflammatory NF-κB antagonist, rescued lung branching and normalized NF-κB signaling in hypoplastic lung explants. Moreover, specific NF-κB inhibition with curcumenol similarly rescued ex vivo lung hypoplasia and restored NF-κB signaling. Lastly, we showed that prenatal intraperitoneal dexamethasone administration to pregnant rat dams carrying fetuses with hypoplastic lungs, significantly improves lung branching and normalizes NF-κB in vivo. Our results indicate that NF-κB is aberrantly activated in human and nitrofen CDH lungs. Anti-inflammatory treatment with dexamethasone and/ or specific NF-κB inhibition should be investigated further as a therapeutic avenue to target lung hypoplasia in CDH.

The interplay between prenatal liver growth and lung development in congenital diaphragmatic hernia.

ObjectiveLiver herniation is a known risk factor for increased severity in CDH and is associated with clinically significant pulmonary hypoplasia and pulmonary hypertension. Better studies are needed to understand the growth of the herniated liver compared to the liver that remains in the abdomen and how this liver growth then affects lung development. Serial hi-resolution fetal MRI enables characterization of liver growth throughout gestation and examination of macroscopic features that may regulate liver growth. Here, we hypothesized that the nature of liver herniation affects liver growth and, in turn, affects lung growth.MethodsClinical data were retrospectively collected from consecutive cases of prenatally diagnosed isolated left-sided or right-sided CDH from June 2006 to August 2021. Only those cases with MRI lung volumetry for both mid-gestation and late-gestation time points were recruited for analysis. Cases with fetal chromosomal abnormalities and other major structural abnormalities were excluded. Fractional liver volume and liver growth was indexed to estimated fetal weight and compared to lung growth.ResultsData was collected from 28 fetuses with a left liver-down CDH (LLD), 37 left liver-up CDH (LLU) and 9 right liver-up CDH (RLU). Overall, RLU fetuses had greater overall and fractional (intra-thoracic vs. intra-abdominal) liver growth when compared to LLD and LLU fetuses. Additionally, intra-thoracic liver growth was consistently slower than intra-abdominal liver growth for either right- or left-sided CDH. When the liver was not herniated, a positive correlation was seen between liver growth and lung growth. However, when the liver was herniated above the diaphragm, this positive correlation was lost.ConclusionRight-sided CDH fetuses exhibit greater liver growth compared to left-sided CDH. Liver herniation disrupts the normal positive correlation between liver and lung growth that is seen when the liver is entirely within the abdomen.

Proteomic Profiling of Hypoplastic Lungs Suggests an Underlying Inflammatory Response in the Pathogenesis of Abnormal Lung Development in Congenital Diaphragmatic Hernia.

The pathogenesis of lung hypoplasia in congenital diaphragmatic hernia (CDH), a common birth defect, is poorly understood. The diaphragmatic defect can be repaired surgically, but the abnormal lung development contributes to a high mortality in these patients. To understand the underlying pathobiology, we compared the proteomic profiles of fetal rat lungs at the alveolar stage (E21) that were either exposed to nitrofen in utero (CDH lungs, n=5) or exposed to vehicle only (non-CDH control lungs, n=5). Pathway analysis of proteomic datasets showed significant enrichment in inflammatory response proteins associated with cytokine signaling and Epstein Barr Virus in nitrofen CDH lungs. Among the 218 significantly altered proteins between CDH and non-CDH control lungs were Tenascin C, CREBBP, LYN, and STAT3. We showed that Tenascin C was decreased around the distal airway branches in nitrofen rat lungs and human CDH lungs, obtained from stillborn fetuses that did not receive pre- or postnatal treatment. In contrast, STAT3 was significantly increased in the airway epithelium of nitrofen lungs at E21. STAT3 inhibition after direct nitrofen exposure to fetal rat lung explants (E14.5) partially rescued the hypoplastic lung phenotype ex vivo by increasing peripheral lung budding. Moreover, we demonstrated that several STAT3-associated cytokines (IL-15, IL-9, andIL-2) are increased in fetal tracheal aspirates of CDH survivors compared with nonsurvivors after fetoscopic endoluminal tracheal occlusion. With our unbiased proteomics approach, we showed for the first time that downstream inflammatory processes are likely involved in the pathogenesis of abnormal lung development in CDH.

Tenascin C is dysregulated in hypoplastic lungs of miR-200b-/- mice.

We previously demonstrated that absence of miR-200b results in abnormal lung development in congenital diaphragmatic hernia due to imbalance between epithelial and mesenchymal cells. Tenascin C is a highly conserved extracellular matrix protein involved in epithelial to mesenchymal transition, tissue regeneration and lung development. Considering the involvement of Tenascin C and miR-200b and their potential interaction, we aimed to study Tenascin C during lung development in the absence of miR-200b. We collected lungs of miR-200b-/- mice (male, 8weeks). We performed Western blot (WB) analysis (N = 6) and immunofluorescence (N = 5) for Tenascin C and alpha smooth muscle actin and RT-qPCR for Tenascin C gene expression (N = 4). Using WB analysis, we observed a decreased total protein abundance of Tenascin C in miR-200b-/- lungs (miR-200b+/+: 3.8 × 107 ± 1 × 107; miR-200b-/-: 1.9 × 107 ± 5 × 106; p = 0.002). Immunofluorescence confirmed decreased total Tenascin C in miR-200b-/- lungs. Tenascin C was significantly decreased in the mesenchyme but relatively increased in the airways of mutant lungs. Total lung RNA expression of Tenascin C was higher in miR-200b-/- lungs. We report dysregulation of Tenascin C in lungs of miR-200b-/- mice. This suggests that absence of miR-200b results in abnormal Tenascin C abundance contributing to the lung hypoplasia observed in miR-200b-/- mice.

Parental risk factors for congenital diaphragmatic hernia \u2013 a large German case-control study

BackgroundEvidence for periconceptional or prenatal environmental risk factors for the development of congenital diaphragmatic hernia (CDH) is still scarce. Here, in a case-control study we investigated potential environmental risk factors in 199 CDH patients compared to 597 healthy control newborns.MethodsThe following data was collected: time of conception and birth, maternal BMI, parental risk factors such as smoking, alcohol or drug intake, use of hairspray, contact to animals and parental chronic diseases. CDH patients were born between 2001 and 2019, all healthy control newborns were born in 2011. Patients and control newborns were matched in the ratio of three to one.ResultsPresence of CDH was significantly associated with maternal periconceptional alcohol intake (odds ratio = 1.639, 95% confidence interval 1.101–2.440, p = 0.015) and maternal periconceptional use of hairspray (odds ratio = 2.072, 95% confidence interval 1.330–3.229, p = 0.001).ConclusionOur study suggests an association between CDH and periconceptional maternal alcohol intake and periconceptional maternal use of hairspray. Besides the identification of novel and confirmation of previously described parental risk factors, our study underlines the multifactorial background of isolated CDH.

EP127 - Evidence that FGFRL1 contributes to congenital diaphragmatic hernia development in humans

Fibroblast growth factor receptor-like 1 (FGFRL1) encodes a transmembrane protein that is related to fibroblast growth factor receptors but lacks an intercellular tyrosine kinase domain. in vitro studies suggest that FGFRL1 inhibits cell proliferation and promotes cell differentiation and cell adhesion. Mice that lack FGFRL1 die shortly after birth from respiratory distress and have abnormally thin diaphragms whose muscular hypoplasia allows the liver to protrude into the thoracic cavity. Haploinsufficiency of FGFRL1 has been hypothesized to contribute to the development of congenital diaphragmatic hernia (CDH) associated with Wolf-Hirschhorn syndrome. However, data from both humans and mice suggest that disruption of one copy of FGFRL1 alone is insufficient to cause diaphragm defects. Here we report a female fetus with CDH whose 4p16.3 deletion allows us to refine the Wolf-Hirschhorn syndrome CDH critical region to an approximately 1.9 Mb region that contains FGFRL1. We also report a male infant with isolated left-sided diaphragm agenesis who carried compound heterozygous missense variants in FGFRL1. These cases provide additional evidence that deleterious FGFRL1 variants may contribute to the development of CDH in humans.

Diaphragmatic Hernia after Radiofrequency Ablation.

Diaphragmatic hernia (DH) is a defect, which can be congenital or can develop later in life. Moreover, chromosomal and genetic abnormalities, environmental exposures, and nutritional deficiencies may be related to the development of congenital DH. In contrast, the risk factors of acquired DH include traumas, such as blunt injuries due to traffic accidents and surgical procedures. We report the case of a 71-year-old man admitted to our gastroenterology department for the treatment of esophageal varices. Four days after the endoscopic treatment, the patient vomited severely and reported severe right upper abdominal pain. He was diagnosed with DH, and surgical fixation was performed. The diaphragmatic injury lesion was located on the estimated needle track of percutaneous radiofrequency ablation, which was performed through the thoracic diaphragm with artificial pleural effusion for hepatocellular carcinoma.

Involvement of YAP and LATS1 in lung development in a rat model of nitrofen-induced congenital diaphragmatic hernia

Purpose: To investigate the role of Hippo pathway in lung development in congenital diaphragmatic hernia (CDH).
 Methods: One oral dose of nitrofen was maternally administered for induction of CDH on embryonic day 9.5 (E 9.5). Sildenafil was administered intragastrically at a dose of 100 mg/kg on E 11.5. Three rat groups were used: control, CDH, and CDH + sildenafil. Cesarean section was used for fetal delivery on E 21.5. Fetuses with left diaphragmatic hernia (except in control rats) were chosen for investigations. Fetal body weight and weight of lung tissue were recorded, and lung histological evaluation, western blot and PCR were carried out after lung processing.
 Results: There was markedly higher expression of YAP in CDH rats than in control rats was unaffected by antenatal sildenafil administration (p < 0.05). However, prenatal sildenafil intervention significantly increased LATS1 expression in the lung of CDH fetuses (p < 0.05).
 Conclusion: These results indicate that increased pulmonary YAP expression in CDH rat model might contribute to pulmonary vascular remodeling and suppression of lung development. Thus, antenatal sildenafil administration not only mitigates abnormal vascular remodeling but also promotes lung development, most likely via increased expression of LATS1.
 Keywords: Congenital diaphragmatic hernia (CDH), Hippo pathway, Lung development, Sildenafil

MiR-130a-5p/Foxa2 axis modulates fetal lung development in congenital diaphragmatic hernia by activating the Shh/Gli1 signaling pathway

AimsCongenital diaphragmatic hernia (CDH) is a lethal birth defect characterized by congenital lung malformation, and the severity of pulmonary hypoplasia directly affects the prognosis of infants with CDH. Using a nitrofen-induced CDH rat model, we previously reported that Foxa2 expression was downregulated in CDH lungs by proteomics analysis. Here, we investigate the role of miR-130a-5p/Foxa2 axis in lung development of the nitrofen-induced CDH and evaluate its potential role in vivo prenatal therapy. Main methodsNitrofen was orally administrated on embryonic day (E) 8.5 to establish a rat CDH model, and fetal lungs were collected on E13.5, E15.5, E17.5, E19.5 and E21.5. The binding sites of miR-130a-5p on Foxa2 mRNA were identified using bioinformatics prediction software and were validated via luciferase assay. The expression levels of miR-130a-5p and Foxa2 were detected using qRT-PCR, ISH, IHC and western blotting. The role of miR-130a-5p/Foxa2 axis in CDH-associated lung development was investigated in ex vivo lung explants. Key findingsWe found that Foxa2 was downregulated in CDH lung tissues, and Foxa2 upregulating improved CDH branching morphogenesis in ex vivo lung explants. Meanwhile, we also showed that miR-130a-5p was significantly upregulated in CDH lungs and thus inversely correlated with Foxa2. Increasing miR-130a-5p abundance with mimics decreases Foxa2-driven Shh/Gli1 signaling and inhibits branching morphogenesis in ex vivo lung explants. SignificanceThis study was the first to show that the miR-130a-5p/Foxa2 axis played a crucial role in CDH-associated pulmonary hypoplasia. These findings may provide relevant insights into the prenatal diagnosis and prenatal therapy of CDH.

MIF inhibition enhances pulmonary angiogenesis and lung development in congenital diaphragmatic hernia.

Congenital diaphragmatic hernia (CDH) is a complex birth anomaly with significant mortality and morbidity. Lung hypoplasia and persistent pulmonary hypertension (PPHN) limit survival in CDH. Macrophage migration inhibitory factor (MIF), a key regulator of innate immunity, is involved in hypoxia-induced vascular remodeling and PPHN. We hypothesized that antenatal inhibition of MIF in CDH fetuses, would reduce vascular remodeling, and improve angiogenesis and lung development. Pregnant rats were randomized into three groups: Control, nitrofen, and nitrofen + ISO-92. Lung volumes of pups were measured by CT scanning. Right ventricular systolic pressure (RVSP) and vascular wall thickness (VWT) were measured together with MIF concentration, angiogenesis markers, lung morphometry, and histology. Prenatal treatment with ISO-92, an MIF inhibitor, improved normalization of static lung volume, lung volume-to-body weight ratio, decreased alveolar septal thickness, RVSP and VWT and improved radial alveolar count as compared to the non-treated group. Expression of MIF was unaffected by ISO-92; however, ISO-92 increased p-eNOS and VEGF activities and reduced arginase 1, 2 and Sflt-1. Prenatal inhibition of MIF activity in CDH rat model improves angiogenesis and lung development. This selective intervention may be a future therapeutic strategy to reduce the morbidity and mortality of this devastating condition.

Regenerative Prophylaxis In Utero.

Technology advances have raised the outlook for regenerative solutions aimed at restoring organ health. Fetal surgery, implemented to reinstate early organ growth and restitute function in select congenital conditions, is increasingly considered with the prospect of improved postnatal outcomes. Herein, we highlight clinical prenatal interventions for rescue of fetal lung development in congenital diaphragmatic hernia and fetal neurological regeneration for spina bifida. Regenerative therapeutic care in utero is poised to transform management algorithms.

The role of FREM2 and FRAS1 in the development of congenital diaphragmatic hernia.

Congenital diaphragmatic hernia (CDH) has been reported twice in individuals with a clinical diagnosis of Fraser syndrome, a genetic disorder that can be caused by recessive mutations affecting FREM2 and FRAS1. In the extracellular matrix, FREM2 and FRAS1 form a self-stabilizing complex with FREM1, a protein whose deficiency causes sac CDH in humans and mice. By sequencing FREM2 and FRAS1 in a CDH cohort, and searching online databases, we identified five individuals who carried recessive or double heterozygous, putatively deleterious variants in these genes which may represent susceptibility alleles. Three of these alleles were significantly enriched in our CDH cohort compared with ethnically matched controls. We subsequently demonstrated that 8% of Frem2ne/ne and 1% of Fras1Q1263*/Q1263* mice develop the same type of anterior sac CDH seen in FREM1-deficient mice. We went on to show that development of sac hernias in FREM1-deficient mice is preceded by failure of anterior mesothelial fold progression resulting in the persistence of an amuscular, poorly vascularized anterior diaphragm that is abnormally adherent to the underlying liver. Herniation occurs in the perinatal period when the expanding liver protrudes through this amuscular region of the anterior diaphragm that is juxtaposed to areas of muscular diaphragm. Based on these data, we conclude that deficiency of FREM2, and possibly FRAS1, are associated with an increased risk of developing CDH and that loss of the FREM1/FREM2/FRAS1 complex, or its function, leads to anterior sac CDH development through its effects on mesothelial fold progression.

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.

Abnormal lung development in congenital diaphragmatic hernia

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

VEGF receptor expression decreases during lung development in congenital diaphragmatic hernia induced by nitrofen

Changes in vascular endothelial growth factor (VEGF) in pulmonary vessels have been described in congenital diaphragmatic hernia (CDH) and may contribute to the development of pulmonary hypoplasia and hypertension; however, how the expression of VEGF receptors changes during fetal lung development in CDH is not understood. The aim of this study was to compare morphological evolution with expression of VEGF receptors, VEGFR1 (Flt-1) and VEGFR2 (Flk-1), in pseudoglandular, canalicular, and saccular stages of lung development in normal rat fetuses and in fetuses with CDH. Pregnant rats were divided into four groups (n=20 fetuses each) of four different gestational days (GD) 18.5, 19.5, 20.5, 21.5: external control (EC), exposed to olive oil (OO), exposed to 100 mg nitrofen, by gavage, without CDH (N-), and exposed to nitrofen with CDH (CDH) on GD 9.5 (term=22 days). The morphological variables studied were: body weight (BW), total lung weight (TLW), left lung weight, TLW/BW ratio, total lung volume, and left lung volume. The histometric variables studied were: left lung parenchymal area density and left lung parenchymal volume. VEGFR1 and VEGFR2 expression were determined by Western blotting. The data were analyzed using analysis of variance with the Tukey-Kramer post hoc test. CDH frequency was 37% (80/216). All the morphological and histometric variables were reduced in the N- and CDH groups compared with the controls, and reductions were more pronounced in the CDH group (P<0.05) and more evident on GD 20.5 and GD 21.5. Similar results were observed for VEGFR1 and VEGFR2 expression. We conclude that N- and CDH fetuses showed primary pulmonary hypoplasia, with a decrease in VEGFR1 and VEGFR2 expression.

Repetitive MR measurements of lung volume in fetuses with congenital diaphragmatic hernia: individual development of pulmonary hypoplasia during pregnancy and calculation of weekly lung growth rates

To investigate individual changes in fetal lung volume (FLV) in fetuses with isolated congenital diaphragmatic hernia (CDH) and to calculate weekly growth rates of the FLV using serial MR examinations during pregnancy. MR-FLV was measured in 89 fetuses with CDH. All fetuses received two MRIs. A mean weekly growth rate of the FLV was determined for each fetus and compared with the growth rate of healthy fetuses. Mean observed-to-expected MR-FLV (o/e MR-FLV) measured at the first MRI was 33.3 ± 12.2% and 29.5 ± 10.9% at the second MRI. In 61% of all fetuses (54/89) the o/e MR-FLV decreased during pregnancy, 26% (23/89) showed an increase in the o/e MR-FLV and 13 % (12/89) had stable values. First and last o/e MR-FLV values were significantly associated with mortality and neonatal extracorporeal membrane oxygenation (ECMO) requirement with a higher prognostic accuracy of MR-FLV measurements near delivery. Patients with CDH had lower weekly lung growth rates than healthy fetuses. There was a significant difference in the mean weekly growth rate between survivors and non-survivors and patients with and without ECMO requirement. Individual development of FLV in patients with CDH during pregnancy is extremely variable. Follow-up MR-FLV measurements are advisable before deciding upon pre- and postnatal therapeutic options. • Lung development in congenital diaphragmatic hernia (CDH) during pregnancy is extremely variable. • MRI demonstrates that lung growth rate is reduced in fetuses with CDH. • The final observed-to-expected fetal lung volume provides the best prognostic information. • Follow-up measurements are advisable before deciding upon therapeutic options.

Mouse model reveals the role of SOX7 in the development of congenital diaphragmatic hernia associated with recurrent deletions of 8p23.1

Recurrent microdeletions of 8p23.1 that include GATA4 and SOX7 confer a high risk of both congenital diaphragmatic hernia (CDH) and cardiac defects. Although GATA4-deficient mice have both CDH and cardiac defects, no humans with cardiac defects attributed to GATA4 mutations have been reported to have CDH. We were also unable to identify deleterious GATA4 sequence changes in a CDH cohort. This suggested that haploinsufficiency of another 8p23.1 gene may contribute, along with GATA4, to the development of CDH. To determine if haploinsufficiency of SOX7-another transcription factor encoding gene-contributes to the development of CDH, we generated mice with a deletion of the second exon of Sox7. A portion of these Sox7(Δex2/+) mice developed retrosternal diaphragmatic hernias located in the anterior muscular portion of the diaphragm. Anterior CDH is also seen in Gata4(+/-) mice and has been described in association with 8p23.1 deletions in humans. Immunohistochemistry revealed that SOX7 is expressed in the vascular endothelial cells of the developing diaphragm and may be weakly expressed in some diaphragmatic muscle cells. Sox7(Δex2/Δex2) embryos die prior to diaphragm development with dilated pericardial sacs and failure of yolk sac remodeling suggestive of cardiovascular failure. Similar to our experience screening GATA4, no clearly deleterious SOX7 sequence changes were identified in our CDH cohort. We conclude that haploinsufficiency of Sox7 or Gata4 is sufficient to produce anterior CDH in mice and that haploinsufficiency of SOX7 and GATA4 may each contribute to the development of CDH in individuals with 8p23.1 deletions.

Myocardium expression of connexin 43, SERCA2a, and myosin heavy chain isoforms are preserved in nitrofen-induced congenital diaphragmatic hernia rat model

Background Previous morphological studies had produced controversial results with regard to heart development in congenital diaphragmatic hernia (CDH), whereas a few publications investigated cardiac function and myocardial maturation. Myocardium maturation is associated with age-dependent increasing of gene expression of gap junction protein connexin 43 (Cx43), adenosine triphosphatase of the sarcoplasmic reticulum (SERCA2a), as well as switching of myosin heavy chains (MHCs) from β to α isoforms. Our aim was to evaluate myocardium maturity in nitrofen-induced CDH rat model. Methods Fetuses from dated pregnant Sprague-Dawley rats were assigned to 3 experimental groups: control, nitrofen (exposed to nitrofen, without CDH), and CDH (exposed to nitrofen, with CDH). Myocardial samples collected from left ventricle free wall were processed to (i) quantification of messenger RNA (mRNA) of Cx43, SERCA2a, α and β MHC isoforms, as well as β-actin (housekeeping gene); and (ii) separation of MHC isoforms ( α and β isoforms) by sodium dodecyl sulfate polyacrylamide gel electrophoresis silver stained. Results We demonstrated that there is no difference in myocardial gene expression of Cx43 (control, 1.0 ± 0.1; nitrofen, 1.1 ± 0.2; CDH, 1.3 ± 0.2) and SERCA2a (control, 1.0 ± 0.1; nitrofen, 0.9 ± 0.1; CDH, 1.0 ± 0.2). Myocardial gene expressions of α and β mRNA of MHC isoforms were slightly decreased both in nitrofen and CDH fetuses when compared with control fetuses, but evaluation of the α-to- β ratios of MHC isoforms at protein level revealed no significant differences between CDH and control (control, 16.9 ± 2.5; CDH, 17.0 ± 2.0). Conclusions Myocardial quantification of Cx43 and SERCA2a mRNA, as well as the expression pattern of MHC isoforms at protein levels, was similar in all studied groups. We predict, therefore, that acute heart failure commonly observed in CDH infants might be attributed predominantly to cardiac overload secondary to severe pulmonary hypertension rather than to myocardial immaturity.