Etiology of congenital diaphragmatic hernia: the retinoid hypothesis

Fetoscopic Endoluminal Tracheal Occlusion-Synergic Therapies in the Prenatal Treatment of Congenital Diaphragmatic Hernia

Congenital diaphragmatic hernia (CDH) is a relatively rare and severe developmental disease. Even with the most recent multidisciplinary therapies, the risk for neonatal mortality and morbidity remains high. Recent advancements in prenatal treatments, alongside experimental and clinical data, suggest that fetoscopic endoluminal tracheal occlusion (FETO) promotes lung development and offers a promising strategy against lung hypoplasia and pulmonary hypertension. It is the only existing direct mechanical therapy that intervenes in the regulation of pulmonary pressure. Its influence on lung development also interferes with tissue homeostasis and cell differentiation; it also enhances inflammation and apoptosis. Its physiopathology on cellular and molecular levels is still poorly understood. Unfortunately, the procedure also carries significant pregnancy-, maternal-, and fetus-related risks. Assessing a multifaceted intervention requires a collective view of all aspects. This scoping review uncovers potential materno-fetal procedure-related risks and highlights innovative solutions. Future research on lung development therapies in CDH may focus on the "dual hit" mechanism, combining molecular-targeting drugs and regenerative medicine with the mechanical nature of FETO for synergistic effects.

Toll-like receptors ligand immunomodulators for the treatment congenital diaphragmatic hernia

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a rare disease that affects the development of the diaphragm, leading to abnormal lung development. Unfortunately, there is no established therapy for CDH. Retinoic acid pathways are implicated in the ethology of CDH and macrophages are known to play a role in repairing organ damage.

METHODS

We have analyzed the effect of several Toll like receptor (TLR) ligands in the nitrofen-induced CDH model in pregnant rats widely used to study this disease and in the G2-GATA4Cre;Wt1fl/fl CDH genetic mice model. Morphometric and histological studies were carried out. Immune cell infiltration was assayed by immunochemistry and immunofluorescence and retinoic pathway gene expression analyzed in vivo and in vitro in macrophages.

RESULTS

We found that administering a single dose of atypical TLR2/4 ligands (CS1 or CS2), 3 days after nitrofen, cured diaphragmatic hernia in 73% of the fetuses and repaired the lesion with complete diaphragm closure being on the other hand nontoxic for the mothers or pups. Moreover, these immunomodulators also improved pulmonary hypoplasia and alveolar maturation and vessel hypertrophy, enhancing pulmonary maturity of fetuses. We also found that CS1 treatment rescued the CDH phenotype in the G2-GATA4Cre;Wt1fl/fl CDH genetic mice model. Only 1 out of 11 mutant embryos showed CDH after CS1 administration, whereas CDH prevalence was 70% in untreated mutant embryos. Mechanistically, CS1 stimulated the infiltration of repairing M2 macrophages (CD206+ and Arg1+) into the damaged diaphragm and reduced T cell infiltration. Additionally, those TLR ligands induced retinol pathway genes, including RBP1, RALDH2, RARα, and RARβ, in the affected lungs and the diaphragm and in macrophages in vitro.

CONCLUSIONS

Our research has shown that TLR ligand immunomodulators that influence anti-inflammatory macrophage activation can be effective in treating CDH, being nontoxic for the mothers or pups suggesting that those TLR ligands are a promising solution for CDH leading to orphan drug designation for CS1. The immune system of the fetus would be responsible for repairing the damage and closure of the hernia in the diaphragm and enhanced proper lung development after CS1 treatment.

Role of genetics and the environment in the etiology of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a congenital malformation characterized by failure of diaphragm closure during embryonic development, leading to pulmonary hypoplasia and pulmonary hypertension, which contribute significantly to morbidity and mortality. The occurrence of CDH and pulmonary hypoplasia is theorized to result from both abnormalities in signaling pathways of smooth muscle cells in pleuroperitoneal folds and mechanical compression by abdominal organs within the chest cavity on the developing lungs. Although, the precise etiology of diaphragm maldevelopment in CDH is not fully understood, it is believed that interplay between genes and the environment contributes to its onset. Approximately 30% of patients with CDH possess chromosomal or single gene defects and these patients tend to have inferior outcomes compared with those without genetic associations. At present, approximately 150 gene variants have been linked to the occurrence of CDH. The variable expression of the CDH phenotype in the presence of a recognized genetic predisposition can be explained by an environmental effect on gene penetrance and expression. The retinoic acid pathway is thought to play an essential role in the interactions of genes and environment in CDH. However, apart from the gradually maturing retinol hypothesis, there is limited evidence implicating other environmental factors in CDH occurrence. This review aims to describe the pathogenesis of CDH by summarizing the genetic defects and potential environmental influences on CDH development.

Epidemiology of congenital diaphragmatic hernia among 24 million Chinese births: a hospital-based surveillance study

BACKGROUND

The prevalence of congenital diaphragmatic hernia (CDH) varies across countries, with limited information available on its epidemiology in China. Our study aimed to investigate the prevalence, time trends, and perinatal outcomes of CDH in China, as well as its associated malformations and potential associations with maternal and infant characteristics.

METHODS

This study included all birth and CDH cases from the Chinese Birth Defects Monitoring Network between 2007 and 2019, with CDH cases classified as either isolated or associated. We employed the joinpoint regression model to calculate the trends of prevalence and the annual percent change, with Poisson regression used for adjusted prevalence rate ratios. A P value ≤ 0.05 was considered statistically significant.

RESULTS

A total of 4397 CDH cases were identified among 24,158,029 births in the study period, yielding prevalence rates of 1.82, 1.13 and 0.69 per 10,000 for overall, isolated, and associated CDH, respectively. The prevalence of each type of CDH increased over time. The prevalence of overall CDH varied significantly by infant sex (male vs. female, 1.91/10,000 vs. 1.63/10,000), maternal residence (urban vs. rural, 2.13/10,000 vs. 1.45/10,000), maternal age (< 20 years, 1.31/10,000; 20-24 years, 1.63/10,000; 25-29 years, 1.80/10,000; 30-34 years, 1.87/10,000; ≥ 35 years, 2.22/10,000), and geographic region (central, 1.64/10,000; east, 2.45/10,000; west, 1.37/10,000). Cardiovascular anomalies were the most common malformations associated with CDH. Infants with associated CDH had a higher risk of premature birth and perinatal death than those with isolated CDH.

CONCLUSION

The increasing prevalence and high perinatal mortality rate of CDH highlight the need for further etiological, epidemiological, and clinical studies among the Chinese population. Video Abstract.

The etiology of congenital diaphragmatic hernia: the retinoid hypothesis 20 years later

Congenital diaphragmatic hernia (CDH) is a severe birth defect and a major cause of neonatal respiratory distress. Impacting ~2-3 in 10,000 births, CDH is associated with a high mortality rate, and long-term morbidity in survivors. Despite the significant impact of CDH, its etiology remains incompletely understood. In 2003, Greer et al. proposed the Retinoid Hypothesis, stating that the underlying cause of abnormal diaphragm development in CDH was related to altered retinoid signaling. In this review, we provide a comprehensive update to the Retinoid Hypothesis, discussing work published in support of this hypothesis from the past 20 years. This includes reviewing teratogenic and genetic models of CDH, lessons from the human genetics of CDH and epidemiological studies, as well as current gaps in the literature and important areas for future research. The Retinoid Hypothesis is one of the leading hypotheses to explain the etiology of CDH, as we continue to better understand the role of retinoid signaling in diaphragm development, we hope that this information can be used to improve CDH outcomes. IMPACT: This review provides a comprehensive update on the Retinoid Hypothesis, which links abnormal retinoic acid signaling to the etiology of congenital diaphragmatic hernia. The Retinoid Hypothesis was formulated in 2003. Twenty years later, we extensively review the literature in support of this hypothesis from both animal models and humans.

Connecting clinical, environmental, and genetic factors point to an essential role for vitamin A signaling in the pathogenesis of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a developmental disorder that results in incomplete diaphragm formation, pulmonary hypoplasia, and pulmonary hypertension. Although a variety of genes have been linked to its etiology, CDH is not a monogenetic disease, and the cause of the condition is still unclear in the vast majority of clinical cases. By comparing human clinical data and experimental rodent data from the literature, we present clear support demonstrating the importance of vitamin A (vitA) during the early window of pregnancy when the diaphragm and lung are forming. Alteration of vitA signaling via dietary and genetic perturbations can create diaphragmatic defects. Unfortunately, vitA deficiency is chronic among people of child-bearing age, and this early window of diaphragm development occurs before many might be aware of pregnancy. Furthermore, there is an increased demand for vitA during this critical period, which exacerbates the likelihood of deficiency. It would be beneficial for the field to further investigate the connections between maternal vitA and CDH incidence, with the goal of determining vitA status as a CDH risk factor. Regular clinical monitoring of vitA levels in child-bearing years is a tractable method by which CDH outcomes could be prevented or improved.

Embryology and anatomy of congenital diaphragmatic hernia

Prenatal and postnatal treatment modalities for congenital diaphragmatic hernia (CDH) continue to improve, however patients still face high rates of morbidity and mortality caused by severe underlying persistent pulmonary hypertension and pulmonary hypoplasia. Though the majority of CDH cases are idiopathic, it is believed that CDH is a polygenic developmental defect caused by interactions between candidate genes, as well as environmental and epigenetic factors. However, the origin and pathogenesis of these developmental insults are poorly understood. Further, connections between disrupted lung development and the failure of diaphragmatic closure during embryogenesis have not been fully elucidated. Though several animal models have been useful in identifying candidate genes and disrupted signalling pathways, more studies are required to understand the pathogenesis and to develop effective preventative care. In this article, we summarize the most recent litterature on disrupted embryological lung and diaphragmatic development associated with CDH.

The role of genes and environment in the etiology of congenital diaphragmatic hernias

Structural birth defects are a common cause of abnormalities in newborns. While there are cases of structural birth defects arising due to monogenic defects or environmental exposures, many birth defects are likely caused by a complex interaction between genes and the environment. A structural birth defect with complex etiology is congenital diaphragmatic hernias (CDH), a common and often lethal disruption in diaphragm development. Mutations in more than 150 genes have been implicated in CDH pathogenesis. Although there is generally less evidence for a role for environmental factors in the etiology of CDH, deficiencies in maternal vitamin A and its derivative embryonic retinoic acid are strongly associated with CDH. However, the incomplete penetrance of CDH-implicated genes and environmental factors such as vitamin A deficiency suggest that interactions between genes and environment may be necessary to cause CDH. In this review, we examine the genetic and environmental factors implicated in diaphragm and CDH development. In addition, we evaluate the potential for gene-environment interactions in CDH etiology, focusing on the potential interactions between the CDH-implicated gene, Gata4, and maternal vitamin A deficiency.

Diagnosis & management of pulmonary hypertension in congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) contributes to neonatal morbidity and mortality worldwide. Pulmonary hypertension (PH) is a key component of CDH pathophysiology and critical consideration for management and therapeutic options. PH associated with CDH has traditionally been attributed to pulmonary vascular maldevelopment and associated lung parenchymal hypoplasia, leading to pre-capillary increase in pulmonary vascular resistance (PVR). However, there is increasing recognition that left ventricular hypoplasia, dysfunction and elevated end diastolic pressure may contribute to post-capillary pulmonary hypertension in CDH patients. The interplay of these mechanisms and associated dysfunction in the right and left ventricles results in variable hemodynamic phenotypes in CDH. Clinical assessment of individual phenotype may help guide personalized management strategies, including effective use of pulmonary vasodilators and extra-corporeal membrane oxygenation. Ongoing investigation of the underlying mechanisms of PH in CDH, and efficacy of physiology-based treatment approaches may support improvement in outcomes in this challenging condition.

A novel surgical toxicological-free model of diaphragmatic hernia in fetal rats

BACKGROUND

Teratogen-induced congenital diaphragmatic hernia (CDH) rat models are commonly used to study the pathophysiology. We have created a new and reliable surgically induced diaphragmatic hernia (DH) model to obtain a purely mechanical DH rat model, and avoid the confounding teratogen-induced effects on the lung development.

METHODS

Fetal DH was surgically created on fetuses at E18.5 and harvested at E21.5 in rats. Four groups were evaluated (n = 16): control (CONT), control exposed to Nitrofen (CONT NIT), DH surgically created (DH SURG), and CDH Nitrofen (CDH NIT). Body weight, total lung weights, and their ratio (BW, TLW, and TLBR) were compared. Air space (AS), parenchyma (PA), total protein, and DNA contents were measured to verify lung hypoplasia. Medial wall thickness (MWT) of pulmonary arterioles was also analyzed.

RESULTS

DH SURG showed significant hypoplasia (decreased in total protein and DNA) vs CONT (p < 0.05); DH SURG vs CDH NIT were similar in TLW and TLBR. DH SURG has less AS than CONT (p < 0.05) and similar PA compared to CONT NIT and CDH NIT, MWT were similarly increased in CONT NIT, DH SURG, and CDH NIT.

CONCLUSIONS

This novel surgical model generates fetal lung hypoplasia contributing to the study of the mechanical compression effect on fetal lung development in DH.

IMPACT

There is a critical need to develop a surgical model in rat to complement the findings of the well-known Nitrofen-induced CDH model. This experimental study is pioneer and can help to understand better the CDH pathophysiological changes caused by herniated abdominal viscera compression against the lung during the final stage of gestation in CDH fetuses, and also to develop more efficient treatments in near future.

Prenatal treprostinil reduces the pulmonary hypertension phenotype in the rat model of congenital diaphragmatic hernia

Background

Persistent pulmonary hypertension (PH) causes significant mortality and morbidity in infants with congenital diaphragmatic hernia (CDH). Since pulmonary vascular abnormalities in CDH develop early during foetal development, we hypothesized that prenatal maternal administration of treprostinil, through its anti-remodelling effect, would improve the PH-phenotype in the nitrofen rat model of CDH.

Methods

In a dose-finding study in normal, healthy pregnant rats, we demonstrated target-range foetal plasma treprostinil concentrations without signs of toxicity. Next, an efficacy study was performed assessing the effects of treprostinil administration at 900 and 1500ng/kg/min from gestational day (GD) 16 until term (GD 21) in CDH and control pups. Pulmonary vascular and airway morphometry, lung mechanics, and expression patterns of genes implicated in the prostaglandin vasoactive pathway were studied.

Findings

In rats maternal administration of 1500ng/kg/min treprostinil reached target foetal concentrations, with no detrimental maternal or foetal side-effects. Prenatal exposure to 900 and 1500 ng/kg/min treprostinil reduced the medial wall thickness (%MWT) (CDH·900, 38.5± 8·4%; CDH.1500, 40·2±9·7%; CDH, 46·6±8·2%; both p < 0·0001) in rat pups with CDH, however increased the %MWT in normal foetuses (C.T.900, 36·6±11·1%; C.T.1500, 36·9±9·3%; C.P., 26·9±6·2%; both p < 0·001). Pulmonary airway development, lung hypoplasia and pulmonary function were unaffected by drug exposure.

Interpretation

In pregnant rats maternally administered treprostinil crosses the placenta, attains foetal target concentrations, and is well tolerated by both mother and foetuses. This report shows a significant reduction of pulmonary arteriole muscularization with prenatal treprostinil in a nitrofen rat model, supporting the promise of this treatment approach for PH of CDH.

Funding

United Therapeutics Corporation provided treprostinil and financial support (ISS-2020-10879).

Global gene expression profiling in congenital diaphragmatic hernia (CDH) patients

Congenital diaphragmatic hernia (CDH) is an anomaly characterized by a defect in the diaphragm, leading to the passage of intra-abdominal organs into the thoracic cavity. Herein, the presented work analyzes the global gene expression profiles in nine CDH and one healthy newborn. All of the patients had left posterolateral (Bochdalek) diaphragmatic hernia, operated via an abdominal approach, and stomach and bowels in the thorax cavity. Some patients also had additional anomalies. A total of 560 differentially regulated genes were measured. Among them, 11 genes showed significant changes in expression associated with lung tissue, vascular structure development, and vitamin A metabolism, which are typical ontologies related to CDH etiology. Among them, SLC25A24 and RAB3IL1 are involved in angiogenesis, HIF1A and FOXC2-AS1 are related with the alveolus, MAGI2-AS3 is associated with the diaphragm, LHX4 and DHH are linked with the lung, and BRINP1, FZD9, WNT4, and BLOC1S1-RDH5 are involved in retinol. Besides, the expression levels of some previously claimed genes with CDH etiology also showed diverse expression patterns in different patients. All these indicated that CDH is a complex, multigenic anomaly, requiring holistic approaches for its elucidation.

Malarial PI4K inhibitor induced diaphragmatic hernias in rat: Potential link with mammalian kinase inhibition

Background

MMV390048 is an aminopyridine plasmodial PI4K inhibitor, selected as a Plasmodium blood‐stage schizonticide for a next generation of malaria treatments to overcome resistance to current therapies. MMV390048 showed an acceptable preclinical safety profile and progressed up to Phase 2a clinical trials. However, embryofetal studies revealed adverse developmental toxicity signals, including diaphragmatic hernias and cardiovascular malformations in rats but not rabbits.

Methods

In vivo exposures of free plasma concentrations of compound in rats were assessed in relation to in vitro human kinase inhibition by MMV390048, using the ADP‐Glo™ Kinase Assay.

Results

We demonstrate a potential link between the malformations seen in the embryofetal developmental (EFD) studies and inhibition of the mammalian PI4Kβ paralogue, as well as inhibition of the off‐target kinases MAP4K4 and MINK1. PI3Kγ may also play a role in the embryofetal toxicity as its in vitro inhibition is covered by in vivo exposure. The exposures in the rabbit embryofetal development studies did not reach concentrations likely to cause PI4K inhibition. Overall, we hypothesize that the in vivo malformations observed could be due to inhibition of the PI4K target in combination with the off‐targets, MAP4K4 and MINK1. However, these relationships are by association and not mechanistically proven.

Conclusions

Deciphering if the EFD effects are dependent on PI4K inhibition, and/or via inhibition of other off‐target kinases will require the generation of novel, more potent, and more specific PI4K inhibitors.

Low maternal vitamin A intake increases the incidence of teratogen induced congenital diaphragmatic hernia in mice

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a severe birth defect associated with high perinatal mortality and long-term morbidity. The etiology of CDH is poorly understood although abnormal retinoid signaling has been proposed to contribute to abnormal diaphragm development. Existing epidemiological data suggest that inadequate dietary vitamin A intake is a risk factor for developing CDH.

METHODS

Using a mouse model of teratogen-induced CDH, the objective of this study was to test the hypothesis that low maternal vitamin A intake contributes to abnormal diaphragm development. To test this hypothesis, we optimized a model of altered maternal dietary vitamin A intake and a teratogenic model of CDH in mice that recapitulates the hallmark features of posterolateral diaphragmatic hernia in humans.

RESULTS

Our data uniquely show that low maternal dietary vitamin A intake and marginal vitamin A status increases the incidence of teratogen-induced CDH in mice.

CONCLUSION

Low dietary vitamin A intake and marginal vitamin A status lead to an increased incidence of teratogen-induced CDH in mice, highlighting the importance of adequate dietary vitamin A intake and CDH risk.

IMPACT

This study describes and validates a mouse model of altered maternal and fetal vitamin A status. This study links existing epidemiological data with a mouse model of teratogen-induced congenital diaphragmatic hernia, highlighting the importance of low maternal vitamin A intake as a risk factor for the development of congenital diaphragmatic hernia. This study supports the Retinoid Hypothesis, which posits that the etiology of congenital diaphragmatic hernia is linked to abnormal retinoid signaling in the developing diaphragm.

Maternal Bochdalek Hernia during Pregnancy: A Systematic Review of Case Reports

Background: Since the first report of a diaphragmatic hernia from Ambroise Paré’s necropsy in 1610, the Bochdalek hernia (BH) of the congenital diaphragmatic hernia (CDH) has been the most common types with high morbidity and mortality in the neonatal period. Due to the nature of the disease, CDH associated with pregnancy is too infrequent to warrant reporting in the literature. Mortality of obstruction or strangulation is mostly due to failure to diagnose symptoms early. Data sources and study selection: A systematic literature search of maternal BH during pregnancy was conducted using the electronic databases (PubMed and EMBASE) from January 1941 to December 2020. Because of the rarity of the disease, this review included all primary studies, including case reports or case series that reported at least one case of maternal BH in pregnant. Searches, paper selection, and data extraction were conducted in duplicate. The analysis was performed narratively regardless of the control groups’ presence due to their rarity. Results: The search retrieved 3450 papers, 94 of which were deemed eligible and led to a total of 43 cases. Results of treatment showed 16 cases in delayed delivery after hernia surgery, 10 cases in simultaneous delivery with hernia surgery, 3 cases in non-surgical treatment, and 14 cases in hernia surgery after delivery. Of 16 cases with delayed delivery after hernia surgery, 13 (81%) cases had emergency surgery and three (19%) cases had surgery after expectant management. Meanwhile, 10 cases underwent simultaneous delivery with hernia surgery, 6 cases (60%) had emergent surgery, and 4 cases (40%) had delayed hernia surgery after expectant management. 3 cases underwent non-surgical treatment. In this review, the maternal death rate and fetal/neonatal loss rate from maternal BH was 5% (2/43) and 16% (7/43), respectively. The preterm birth rate has been reported in 35% (15/43) of maternal BH, resulting from maternal deaths in 13% (2/15) of cases and 6 fetal loss in 40% (6/15) of cases; 44% (19/43) of cases demonstrated signs of bowel obstruction, ischemia, or perforation of strangulated viscera in the operative field, resulting from maternal deaths in 11% (2/19) of cases and fetal-neonatal loss in 21% (4/19) of cases. Conclusion: Early diagnosis and surgical intervention are imperative, as a gangrenous or non-viable bowel resection significantly increases mortality. Therefore, multidisciplinary care should be required in maternal BH during pregnancies that undergo surgically repair, and individualized care allow for optimal results for the mother and fetus.

Management of Congenital Diaphragmatic Hernia (CDH): Role of Molecular Genetics

Congenital diaphragmatic hernia (CDH) is a relatively common major life-threatening birth defect that results in significant mortality and morbidity depending primarily on lung hypoplasia, persistent pulmonary hypertension, and cardiac dysfunction. Despite its clinical relevance, CDH multifactorial etiology is still not completely understood. We reviewed current knowledge on normal diaphragm development and summarized genetic mutations and related pathways as well as cellular mechanisms involved in CDH. Our literature analysis showed that the discovery of harmful de novo variants in the fetus could constitute an important tool for the medical team during pregnancy, counselling, and childbirth. A better insight into the mechanisms regulating diaphragm development and genetic causes leading to CDH appeared essential to the development of new therapeutic strategies and evidence-based genetic counselling to parents. Integrated sequencing, development, and bioinformatics strategies could direct future functional studies on CDH; could be applied to cohorts and consortia for CDH and other birth defects; and could pave the way for potential therapies by providing molecular targets for drug discovery.

Inhibition of triple negative breast cancer metastasis and invasiveness by novel drugs that target epithelial to mesenchymal transition

Invasive breast cancer (BrCa) is predicted to affect 1 in 9 women in a lifetime;1 in 32 will die from this disease. The most aggressive forms of BrCa, basal-like/triple-negative phenotype (TNBC), are challenging to treat and result in higher mortality due high number of metastatic cases. There is a paucity of options for TNBC treatment, which highlights the need for additional innovative treatment approaches. NIH-III mice were injected in the abdominal mammary fat pad with luciferase-expressing derivative of the human TNBC cell line, MDA-MB-231 cells. Animals were gavage-fed with nitrofen at the doses of 1, 3 or 6 mg/kg/alternate days. However, several structural properties/components of nitrofen raise concerns, including its high lipophilicity (cLogP of nearly 5) and a potential toxophore in the form of a nitroarene group. Therefore, we developed analogues of nitrofen which lack the nitro group and/or have replaced the diaryl ether linker with a diarylamine that could allow modulation of polarity. In vitro anti-invasiveness activity of nitrofen analogues were evaluated by quantitative determination of invasion of MDA-MB-231-Luciferase cells through Matrigel using a Boyden chamber. Our in vivo data show that nitrofen efficiently blocks TNBC tumor metastasis. In vitro data suggest that this is not due to cytotoxicity, but rather is due to impairment of invasive capacity of the cells. Further, using an in vitro model of EMT, we show that nitrofen interferes with the process of EMT and promotes mesenchymal to epithelial transformation. In addition, we show that three of the nitrofen analogues significantly reduced invasive potential of TNBC cells, which may, at least partially, be attributed to the analogues' ability to promote mesenchymal to epithelial-like transformation of TNBC cells. Our study shows that nitrofen, and more importantly its analogues, are significantly effective in limiting the invasive potential of TNBC cell lines with minimal cytotoxic effect. Further, we demonstrate that nitrofen its analogues, are very effective in reversing mesenchymal phenotype to a more epithelial-like phenotype. This may be significant for the treatment of patients with mesenchymal-TNBC tumor subtype who are well known to exhibit high resistance to chemotherapy.

Defective mesothelium and limited physical space are drivers of dysregulated lung development in a genetic model of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a developmental disorder associated with diaphragm defects and lung hypoplasia. The etiology of CDH is complex and its clinical presentation is variable. We investigated the role of the pulmonary mesothelium in dysregulated lung growth noted in the Wt1 knockout mouse model of CDH. Loss of WT1 leads to intrafetal effusions, altered lung growth, and branching defects prior to normal closure of the diaphragm. We found significant differences in key genes; however, when Wt1 null lungs were cultured ex vivo, growth and branching were indistinguishable from wild-type littermates. Micro-CT imaging of embryos in situ within the uterus revealed a near absence of space in the dorsal chest cavity, but no difference in total chest cavity volume in Wt1 null embryos, indicating a redistribution of pleural space. The altered space and normal ex vivo growth suggest that physical constraints are contributing to the CDH lung phenotype observed in this mouse model. These studies emphasize the importance of examining the mesothelium and chest cavity as a whole, rather than focusing on single organs in isolation to understand early CDH etiology.

Isolated congenital diaphragm hernia associated with homozygous SLIT3 gene variant in dizygous twins

Congenital diaphragmatic hernia (CDH) is a serious life-threatening birth defect characterized by abnormal development in the muscular or tendinous portion of the diaphragm during embryogenesis. Despite its high incidence, the etiology of CDH hasn't been fully understood. Genetic factors are important in pathogenesis; however, few single genes have been definitively implicated in human CDH. SLIT1, SLIT2, and SLIT3 (slit guidance ligand) are three human homologs of the drosophila Slit gene. They interact with roundabout (Robo) homolog receptors to affect cell migration, adhesion, cell motility, and angiogenesis and play important roles in cell signaling pathways including the guidance of axons. In this report, we presented dizygous twin babies with CDH related to the SLIT3 gene variant. Previous studies showed that Slit3 null mice had congenital diaphragmatic hernias on or near the ventral midline portion of the central tendon. This is the first report of homozygous SLIT3 variant associated with CDH in humans.

Perspective on Similarities and Possible Overlaps of Congenital Disease Formation-Exemplified on a Case of Congenital Diaphragmatic Hernia and Neuroblastoma in a Neonate

The coincidence of two rare diseases such as congenital diaphragmatic hernia (CDH) and neuroblastoma is exceptional. With an incidence of around 2–3:10,000 and 1:8000 for either disease occurring on its own, the chance of simultaneous presentation of both pathologies at birth is extremely low. Unfortunately, the underlying processes leading to congenital malformation and neonatal tumors are not yet thoroughly understood. There are several hypotheses revolving around the formation of CDH and neuroblastoma. The aim of our study was to put the respective hypotheses of disease formation as well as known factors in this process into perspective regarding their similarities and possible overlaps of congenital disease formation. We present the joint occurrence of these two rare diseases based on a patient presentation and immunochemical prognostic marker evaluation. The aim of this manuscript is to elucidate possible similarities in the pathogeneses of both disease entities. Discussed are the role of toxins, cell differentiation, the influence of retinoic acid and NMYC as well as of hypoxia. The detailed discussion reveals that some of the proposed pathophysiological mechanisms of both malformations have common aspects. Especially disturbances of the retinoic acid pathway and NMYC expression can influence and disrupt cell differentiation in either disease. Due to the rarity of both diseases, interdisciplinary efforts and multi-center studies are needed to investigate the reasons for congenital malformations and their interlinkage with neonatal tumor disease.

Impact of congenital diaphragmatic hernia on diaphragm muscle function in neonatal rats

Congenital diaphragmatic hernia (CDH) is characterized by incomplete partitioning of the thoracic and abdominal cavities by the diaphragm muscle (DIAm). The resulting in utero invasion of the abdominal viscera into the thoracic cavity leads to impaired fetal breathing movements, severe pulmonary hypoplasia, and pulmonary hypertension. We hypothesized that in a well-established rodent model of Nitrofen-induced CDH, DIAm isometric force generation, and DIAm fiber cross-sectional areas would be reduced compared with nonlesioned littermate and Control pups. In CDH and nonlesioned pups at embryonic day 21 or birth, DIAm isometric force responses to supramaximal field stimulation (200 mA, 0.5 ms duration pulses in 1-s duration trains at rates ranging from 10 to 100 Hz) was measured ex vivo. Further, DIAm fatigue was determined in response to 120 s of repetitive stimulation at 40 Hz in 330-ms duration trains repeated each second. The DIAm was then stretched to L_o, frozen, and fiber cross-sectional areas were measured in 10 μm transverse sections. In CDH pups, there was a marked reduction in DIAm-specific force and force following 120 s of fatiguing contraction. The cross-sectional area of DIAm fibers was also reduced in CDH pups compared with nonlesioned littermates and Control pups. These results show that CDH is associated with a dramatic weakening of the DIAm, which may contribute to poor survival despite various surgical efforts to repair the hernia and improve lung development.NEW & NOTEWORTHY There are notable respiratory deficits related to congenital diaphragmatic hernia (CDH), yet the contribution, if any, of frank diaphragm muscle weakness to CDH is unexplored. Here, we use the well-established Nitrofen teratogen model to induce CDH in rat pups, followed by diaphragm muscle contractility and morphological assessments. Our results show diaphragm muscle weakness in conjunction with reduced muscle fiber density and size, contributing to CDH morbidity.

Resolving the heterogeneity of diaphragmatic mesenchyme: a novel mouse model of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a relatively common developmental defect with considerable mortality and morbidity. Formation of the diaphragm is a complex process that involves several cell types, each with different developmental origins. Owing to this complexity, the aetiology of CDH is not well understood. The pleuroperitoneal folds (PPFs) and the posthepatic mesenchymal plate (PHMP) are transient structures that are essential during diaphragm development. Using several mouse models, including lineage tracing, we demonstrate the heterogeneous nature of the cells that make up the PPFs. The conditional deletion of Wilms tumor 1 homolog (Wt1) in the non-muscle mesenchyme of the PPFs results in CDH. We show that the fusion of the PPFs and the PHMP to form a continuous band of tissue involves movements of cells from both sources. The PPFs of mutant mice fail to fuse with the PHMP and exhibit increased RALDH2 (also known as ALDH1A2) expression. However, no changes in the expression of genes (including Snai1, Snai2, Cdh1 and Vim) implicated in epithelial-to-mesenchymal transition are observed. Additionally, the mutant PPFs lack migrating myoblasts and muscle connective tissue fibroblasts (TCF4⁺/GATA4⁺), suggesting possible interactions between these cell types. Our study demonstrates the importance of the non-muscle mesenchyme in development of the diaphragm.

Update on Congenital Diaphragmatic Hernia

Congenital diaphragmatic hernia (CDH) is a rare developmental defect of the diaphragm, characterized by herniation of abdominal contents into the chest that results in varying degrees of pulmonary hypoplasia and pulmonary hypertension (PH). Significant advances in the prenatal diagnosis and identification of prognostic factors have resulted in the continued refinement of the approach to fetal therapies for CDH. Postnatally, protocolized approaches to lung-protective ventilation, nutrition, prevention of infection, and early aggressive management of PH have led to improved outcomes in infants with CDH. Advances in our understanding of the associated left ventricular (LV) hypoplasia and myocardial dysfunction in infants with severe CDH have allowed for the optimization of hemodynamics and management of PH. This article provides a comprehensive review of CDH for the anesthesiologist, focusing on the complex pathophysiology, advances in prenatal diagnosis, fetal interventions, and optimal postnatal management of CDH.

Extracellular Vesicles Attenuate Nitrofen-Mediated Human Pulmonary Artery Endothelial Dysfunction: Implications for Congenital Diaphragmatic Hernia

Congenital diaphragmatic hernia (CDH) leads to pathophysiologic pulmonary vasoreactivity. Previous studies show that mesenchymal stromal cell-derived extracellular vesicles (MSCEv) inhibit lung inflammation and vascular remodeling. We characterize MSCEv and human pulmonary artery endothelial cell (HPAEC) interaction, as well as the pulmonary artery (PA) response to MSCEv treatment. HPAECs were cultured with and without exposure to nitrofen (2,4-dichloro-phenyl-p-nitrophenylether) and treated with MSCEv. HPAEC viability, architecture, production of reactive oxygen species (ROS), endothelial dysfunction-associated protein levels (PPARγ, LOX-1, LOX-2, nuclear factor-κB [NF-κB], endothelial NO synthase [eNOS], ET-1 [endothelin 1]), and the nature of MSCEv-cellular interaction were assessed. Newborn rodents with and without CDH (nitrofen model and Sprague-Dawley) were treated with intravascular MSCEv or vehicle control, and their PAs were isolated. Contractility was assessed by wire myography. The contractile (KCL and ET-1) and relaxation (fasudil) responses were evaluated. HPAEC viability correlated inversely with nitrofen dose, while architectural compromise was directly proportional. There was a 2.1 × increase in ROS levels in nitrofen HPAECs (P < 0.001), and MSCEv treatment attenuated ROS levels by 1.5 × versus nitrofen HPAECs (P < 0.01). Nitrofen-induced alterations in endothelial dysfunction-associated proteins are shown, and exposure to MSCEv restored more physiologic expression. Nitrofen HPAEC displayed greater MSCEv uptake (80% increase, P < 0.05). Adenosine, a clathrin-mediated endocytosis inhibitor, decreased uptake by 46% (P < 0.05). CDH PA contraction was impaired with KCL (108.6% ± 1.4% vs. 112.0% ± 1.4%, P = 0.092) and ET-1 (121.7% ± 3.0% vs. 131.2% ± 1.8%, P < 0.01). CDH PA relaxation was impaired with fasudil (32.2% ± 1.9% vs. 42.1% ± 2.2%, P < 0.001). After MSCEv treatment, CDH PA contraction improved (125.9% ± 3.4% vs. 116.4 ± 3.5, P = 0.06), and relaxation was unchanged (32.5% ± 3.2% vs. 29.4% ± 3.1%, P = 0.496). HPAEC exposure to nitrofen led to changes consistent with vasculopathy in CDH, and MSCEv treatment led to a more physiologic cellular response. MSCEv were preferentially taken up by nitrofen-treated cells by clathrin-dependent endocytosis. In vivo, MSCEv exposure improved PA contractile response. These data reveal mechanisms of cellular and signaling alterations that characterize MSCEv-mediated attenuation of pulmonary vascular dysfunction in CDH-associated pulmonary hypertension.

The influence of genetics in congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a common birth defect that is associated with significant morbidity and mortality, especially when associated with additional congenital anomalies. Both environmental and genetic factors are thought to contribute to CDH. The genetic contributions to CDH are highly heterogeneous and incompletely defined. No one genetic cause accounts for more than 1-2% of CDH cases. In this review, we summarize the known genetic causes of CDH from chromosomal anomalies to individual genes. Both de novo and inherited variants contribute to CDH. Genes causing CDH are increasingly identified from animal models and from genomic strategies including exome and genome sequencing in humans. CDH genes are often transcription factors, genes involved in cell migration or the components of extracellular matrix. We provide clinical genetic testing strategies in the clinical evaluation that can identify a genetic cause in up to ∼30% of patients with non-isolated CDH and can be useful to refine prognosis, identify associated medical and neurodevelopmental issues to address, and inform family planning options.

Perinatal Undernutrition, Metabolic Hormones, and Lung Development

Maternal and perinatal undernutrition affects the lung development of litters and it may produce long-lasting alterations in respiratory health. This can be demonstrated using animal models and epidemiological studies. During pregnancy, maternal diet controls lung development by direct and indirect mechanisms. For sure, food intake and caloric restriction directly influence the whole body maturation and the lung. In addition, the maternal food intake during pregnancy controls mother, placenta, and fetal endocrine systems that regulate nutrient uptake and distribution to the fetus and pulmonary tissue development. There are several hormones involved in metabolic regulations, which may play an essential role in lung development during pregnancy. This review focuses on the effect of metabolic hormones in lung development and in how undernutrition alters the hormonal environment during pregnancy to disrupt normal lung maturation. We explore the role of GLP-1, ghrelin, and leptin, and also retinoids and cholecalciferol as hormones synthetized from diet precursors. Finally, we also address how metabolic hormones altered during pregnancy may affect lung pathophysiology in the adulthood.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Gene ontology enrichment analysis of congenital diaphragmatic hernia-associated genes

Congenital diaphragmatic hernia (CDH) is a commonly occurring major congenital anomaly with a profound impact on neonatal mortality. The etiology of CDH is poorly understood and is complicated by multiple clinical presentations, reflecting the location and type of diaphragm defect. With the increased power of genetic screening, more genes are being associated with CDH, creating a knowledge gap between CDH-associated genes and their contribution to diaphragm embryogenesis. Our goal was to investigate CDH-associated genes and identify common pathways that may lead to abnormal diaphragm development. A comprehensive list of CDH-associated genes was identified from the literature and categorized according to multiple factors, including type of CDH. We undertook a large-scale gene function analysis using gene ontology to identify significantly enriched biological pathways and molecular functions associated with our gene set. We identified 218 CDH-associated genes. Our gene ontology analysis showed that genes representing distinct biological pathways are significantly enriched in relation to different clinical presentations of CDH. This includes retinoic acid signaling in Bochdalek CDH, myogenesis in diaphragm eventration, and angiogenesis in central tendon defects. We have identified unique genotype-phenotype relationships highlighting the major genetic drivers of the different types of CDH.

Assessment of the nitrofen model of congenital diaphragmatic hernia and of the dysregulated factors involved in pulmonary hypoplasia

PURPOSE

To study pulmonary hypoplasia (PH) associated with congenital diaphragmatic hernia (CDH), investigators have been employing a fetal rat model based on nitrofen administration to dams. Herein, we aimed to: (1) investigate the validity of the model, and (2) synthesize the main biological pathways implicated in the development of PH associated with CDH.

METHODS

Using a defined strategy, we conducted a systematic review of the literature searching for studies reporting the incidence of CDH or factors involved in PH development. We also searched for PH factor interactions, relevance to lung development and to human PH.

RESULTS

Of 335 full-text articles, 116 reported the incidence of CDH after nitrofen exposure or dysregulated factors in the lungs of nitrofen-exposed rat fetuses. CDH incidence: 54% (27-85%) fetuses developed a diaphragmatic defect, whereas the whole litter had PH in varying degrees. Downregulated signaling pathways included FGF/FGFR, BMP/BMPR, Sonic Hedgehog and retinoid acid signaling pathway, resulting in a delay in early epithelial differentiation, immature distal epithelium and dysfunctional mesenchyme.

CONCLUSIONS

The nitrofen model effectively reproduces PH as it disrupts pathways that are critical for lung branching morphogenesis and alveolar differentiation. The low CDH rate confirms that PH is an associated phenomenon rather than the result of mechanical compression alone.

Morgagni Hernia Repair: A Review

Anteromedial subcostosternal defects, also known as a diaphragmatic hernia of Morgagni (MH), allow potentially life-threatening herniation of the abdominal organs into the thorax. Constituting only a small fraction of all types of congenital diaphragmatic hernias, correct diagnosis of MH is often delayed, owing in large part to nonspecific associated respiratory and gastrointestinal complaints. Once identified, the primary management for both symptomatic and incidentally discovered asymptomatic cases of MH are surgical correction because the herniated contents present increasing risk for strangulation. Various thoracic and abdominal surgical approaches have been described without a clear consensus on preference for operative repair technique. In this article, the literature regarding management of MH within the past decade is reviewed, and an illustrative case of laparoscopic repair of a MH with novel reinforcement using a Falciform ligament onlay flap is presented.

Congenital diaphragmatic hernias: from genes to mechanisms to therapies

Congenital diaphragmatic hernias (CDHs) and structural anomalies of the diaphragm are a common class of congenital birth defects that are associated with significant morbidity and mortality due to associated pulmonary hypoplasia, pulmonary hypertension and heart failure. In ∼30% of CDH patients, genomic analyses have identified a range of genetic defects, including chromosomal anomalies, copy number variants and sequence variants. The affected genes identified in CDH patients include transcription factors, such as GATA4, ZFPM2, NR2F2 and WT1, and signaling pathway components, including members of the retinoic acid pathway. Mutations in these genes affect diaphragm development and can have pleiotropic effects on pulmonary and cardiac development. New therapies, including fetal endoscopic tracheal occlusion and prenatal transplacental fetal treatments, aim to normalize lung development and pulmonary vascular tone to prevent and treat lung hypoplasia and pulmonary hypertension, respectively. Studies of the association between particular genetic mutations and clinical outcomes should allow us to better understand the origin of this birth defect and to improve our ability to predict and identify patients most likely to benefit from specialized treatment strategies.

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.

Seasonality, Epidemiology and Outcome of Congenital Diaphragmatic Hernia in South West of Iran

INTRODUCTION

The pathogenesis of congenital diaphragmatic hernia (CDH) is not clear. Risk factors including environmental factors have been implicated in the pathogenesis of few congenital anomalies. We aimed to assess the effect of season on the incidence of CDH and mortality rate in the southwest of Iran.

MATERIAL AND METHODS

In this retrospective study, the records of 60 patients with CDH who were admitted at Neonatal Intensive Care Unit (NICU) of Imam Khomeini Hospital of Ahvaz, Iran were evaluated.

RESULTS

Assuming that all the neonates born with CDH in the region reach this hospital, overall CDH prevalence rate was 1.09 per 10 000 total births. Conceptions in spring and summer in this region had statistically significantly higher incidence of CDH. Survival rate in the series was 41.6%.

CONCLUSION

Seasonal variation has impact on the incidence of CDH. Mortality rate in neonates with CDH is still very high.

Congenital diaphragmatic hernia with concurrent aplasia of the pericardium in a foal

Background

In veterinary medicine congenital abnormalities of the diaphragm and pericardium are rare, idiopathic malformations, being reported mainly in dogs. This report documents an unusual case of developmental defects in a foal consisting of diaphragmatic hernia concurrent with pericardial aplasia.

Case presentation

Following a normal delivery, a full term, female Friesian stillborn foal with the placenta was presented for necropsy. External morphological examination indicated a normally developed foal. At necropsy, a large oval defect (approximately 20 × 15 cm in size) was observed in the left-dorsal side of the diaphragm (left lumbocostal triangle). This defect allowed the intestinal loops, spleen and partially the liver to translocate into the thorax. The loops of the left ascending colon, including the pelvic flexure and partially the small intestine covered the cranial and dorsal posterior parts of the heart due to the complete absence of the left pericardium. The remaining pericardium presented as a white, semi-transparent strip, partially covering the right side of the heart. The left lung and the main bronchus were severely hypoplastic to approximately one-fifth the size of their right homologue. The intermediate part of the liver, containing mainly the enlarged quadrate lobe was translocated in the thorax, severely enlarged and showed marked fibrosis. Histologically in the herniated lobes we diagnosed hepatic chronic passive congestion, telangiectasia and medial hypertrophy of blood vessels.

Conclusion

Concomitant malformation involving diaphragmatic hernia and pericardial aplasia in horses have not been previously reported. Moreover, this is the first case describing pericardial aplasia in horse.

Lung growth factors in the amniotic fluid of normal pregnancies and with congenital diaphragmatic hernia

AIM

Respiratory failure secondary to pulmonary hypoplasia is the main cause of death in congenital diaphragmatic hernia (CDH). Lung growth is regulated by growth factors (GFs), whose imbalances are reported in pathological conditions. We measured amniotic fluid levels of GFs, regulating lung development, in pregnancies with CDH and compared them with normal gestations.

METHODS

Amniotic fluid was collected at amniocentesis and delivery from 4 women carrying fetuses with CDH and 12 with normal pregnancy. GFs were isolated and quantified. Same GFs were measured in lung biopsies collected during autopsy of three newborns dead of CDH.

RESULTS

Impairment expression of lung GFs in the amniotic fluid of CDH pregnancies in comparison with normal was found. Fibroblast growth factor 10 (FGF10), fibroblast growth factor 7, vascular endothelial growth factor and transforming growth factor β (TGFβ) were decreased at amniocentesis, while platelet-derived growth factor (PDGF) increased. While FGF10 and PDGF tended to normalize at delivery, epidermal growth factor increased and TGFβ was still decreased. Same GFs were similarly expressed in both lungs of babies dead of CDH.

CONCLUSION

Anomalies in lung GFs expression of embryos and fetuses with CDH can be detected by measuring their levels in the amniotic fluid during pregnancy. Further investigation would help to correlate prenatal expression of GFs and clinical outcome of babies with CDH after birth.

Metabolic disturbances of the vitamin A pathway in human diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a common life-threatening congenital anomaly resulting in high rates of perinatal death and neonatal respiratory distress. Some of the nonisolated forms are related to single-gene mutations or genomic rearrangements, but the genetics of the isolated forms (60% of cases) still remains a challenging issue. Retinoid signaling (RA) is critical for both diaphragm and lung development, and it has been hypothesized that subtle disruptions of this pathway could contribute to isolated CDH etiology. Here we used time series of normal and CDH lungs in humans, in nitrofen-exposed rats, and in surgically induced hernia in rabbits to perform a systematic transcriptional analysis of the RA pathway key components. The results point to CRPBP2, CY26B1, and ALDH1A2 as deregulated RA signaling genes in human CDH. Furthermore, the expression profile comparisons suggest that ALDH1A2 overexpression is not a primary event, but rather a consequence of the CDH-induced lung injury. Taken together, these data show that RA signaling disruption is part of CDH pathogenesis, and also that dysregulation of this pathway should be considered organ specifically.

Congenital diaphragmatic hernia: where and what is the evidence?

Congenital diaphragmatic hernia (CDH) retains high mortality and morbidity due to lung hypoplasia, pulmonary hypertension and severe co-existent anomalies. This article offers a comprehensive state-of-the-art review for the paediatric surgeon whilst also describing key contributions from the basic sciences in the search to uncover the cause of the birth defect together with efforts to develop new and better therapies for CDH.

Congenital diaphragmatic hernia

Congenital diaphragmatic hernia is an uncommon congenital anomaly of the diaphragm with pulmonary hypoplasia and persistent pulmonary hypertension as serious consequences. Despite recent advances in therapy, congenital diaphragmatic hernia remains a challenging condition. Best treatment strategies are still largely unknown, and practice strategies vary widely among different centres. Additionally, as congenital diaphragmatic hernia is a relatively uncommon condition, it is difficult to recruit sufficient numbers of patients for clinical trials. In recent years, survival rates of congenital diaphragmatic hernia patients appear to have increased. With the progressively improved survival rates, the long-term prognosis and quality of life of patients have become an increasingly important issue. Survivors have been shown to be at risk for many long-term morbidities, which highlights the importance of long-term follow-up of these children. The aim of this review is to give an overview of the current knowledge regarding congenital diaphragmatic hernia.

Doppler parameters of fetal lung hypoplasia and impact of sildenafil

OBJECTIVE

Congenital diaphragmatic hernia (CDH) is clinically challenging because of associated lung hypoplasia (LH). There have been no validated parameters to evaluate fetal LH severity. Sildenafil has been shown to improve LH mass in nitrofen-induced pulmonary artery (PA) models, but the pulmonary vascular tone has not been evaluated in vivo. The aim of this study was to identify the PA Doppler parameter that best predicts LH severity and to investigate the efficacy of antenatal sildenafil treatment in experimental CDH.

STUDY DESIGN

Nitrofen (50-60% CDH in offspring) or vehicle on E9.5 and sildenafil or vehicle on E11.5-20.5 were administrated to pregnant rats. On E20.5, PA Doppler indices were investigated with and without maternal hyperoxia. The presence/absence of CDH, lung/body weight ratio and radial saccular count were assessed at E20.5.

RESULTS

At baseline, CDH rats had lower PA Doppler acceleration/ejection time ratios and pulsatility index (PI). Maternal hyperoxia resulted in a significant decrease in the PA/PI suggesting pulmonary vasodilation. In contrast, in CDH fetuses, the ipsilateral PA/PI showed little or no response to hyperoxia (P > .05), and in those with LH, PI response to maternal hyperoxia correlated positively with hernia, lung/body weight ratio (r = 0.70, P = .01). Maternal sildenafil therapy significantly improved PA response to hyperoxia and lung growth in CDH fetuses (P < .01).

CONCLUSION

Pulmonary vasodilation that occurs in E20.5 fetal rats in response to maternal hyperoxia is blunted in CDH. Change in PA/PI with hyperoxia is a useful predictor of LH severity. Sildenafil improves pulmonary vascular response and lung growth in fetal CDH.

Nontraumatic Liver Herniation through a Right–Sided Congenital Diaphragmatic Hernia of Morgagni: An Autopsy Case Report with a Review of Liver Herniations through the Defect and a Review of the Defect

Congenital diaphragmatic hernia of Morgagni (CMH) is a rare developmental defect that develops during the development of the human diaphragm. It is usually right-sided and tends to produce symptoms in later life when abdominal viscera herniate into the chest cavities.

Herniations of the liver through this defect into the chest cavities are rare and are often not clinically suspected even when they are associated with symptoms. The amounts of liver tissue involved are usually small, do not cause symptoms and are often an incidental finding during imaging studies of the chest for unrelated symptoms.

This case report documents a clinically unrecognized incidental herniation of the liver into the right chest cavity through a CMH. The report also reviews previously reported cases of liver herniations through a CMH and the possible causes of the defect.

New Insights into Congenital Diaphragmatic Hernia - A Surgeon's Introduction to CDH Animal Models

In recent decades, new research into the developmental defects and pathophysiological basis of congenital diaphragmatic hernia (CDH) has revealed opportunities for the development of innovative therapies. Importantly, the use of animal models to represent this anomaly in the laboratory has resulted in the discovery of many important genetic, epigenetic, and other molecular contributors to this condition. In this review, the most commonly used and newly devised animal models of CDH are presented to familiarize the reader with the latest innovations in the basic sciences.

Duplication of the ALDH1A2 gene in association with pentalogy of Cantrell: a case report

Introduction

The pentalogy of Cantrell is rare clustering of congenital defects, first described by Cantrell and colleagues in 1958. The exact pathogenesis for the pentalogy remains unknown and no specific genetic abnormalities have been correlated; however, a failure of embryogenesis has been suspected. The microduplication of chromosome 15q21.3 (57,529,846 to 58,949,448) found in our patient with pentalogy of Cantrell has not been described previously.

Case presentation

We describe a case of a newborn Caucasian male baby with prenatally diagnosed pentalogy of Cantrell and a novel maternally inherited copy number variant detected by chromosome microarray analysis. Among the genes within the duplicated region is ALDH1A2, encoding the enzyme retinaldehyde dehydrogenase type 2.

Conclusion

Vital for retinoic acid synthesis during early development, ALDH1A2 has previously been demonstrated in animal models to have a strong association with congenital heart disease and diaphragmatic hernia, two key elements comprising pentalogy of Cantrell. It is possible that perturbation of retinoic acid levels during development secondary to this microduplication could underlie the pathology observed in the current case of pentalogy of Cantrell.

Looking beyond PPHN: the unmet challenge of chronic progressive pulmonary hypertension in the newborn

Abstract Infants with forms of pulmonary hypertension (PH) that persist or develop beyond the first week of life are an understudied group of patients with up to 40%-60% mortality. The clinical management of the progressive PH that develops in these infants is challenging because of the nonspecific signs and symptoms of clinical presentation, the limited diagnostic sensitivity of standard echocardiographic techniques, and the lack of proven therapies. The signaling mechanisms that underlie the structural and functional abnormalities in the pulmonary circulation of these infants are not yet clear. The ability to improve outcomes for these patients awaits technological advances to improve diagnostic capabilities and therapeutic discoveries made in basic science laboratories that can be tested in randomized clinical trials.