Cellular origins and translational approaches to congenital diaphragmatic hernia.

Congenital Diaphragmatic Hernia (CDH) is a complex developmental abnormality characterized by abnormal lung development, a diaphragmatic defect and cardiac dysfunction. Despite significant advances in management of CDH, mortality and morbidity continue to be driven by pulmonary hypoplasia, pulmonary hypertension, and cardiac dysfunction. The etiology of CDH remains unknown, but CDH is presumed to be caused by a combination of genetic susceptibility and external/environmental factors. Current research employs multi-omics technologies to investigate the molecular profile and pathways inherent to CDH. The aim is to discover the underlying pathogenesis, new biomarkers and ultimately novel therapeutic targets. Stem cells and their cargo, non-coding RNAs and agents targeting inflammation and vascular remodeling have produced promising results in preclinical studies using animal models of CDH. Shortcomings in current therapies combined with an improved understanding of the pathogenesis in CDH have given rise to novel promising experimental treatments that are currently being evaluated in clinical trials. This review provides insight into current developments in translational research, ranging from the cellular origins of abnormal cardiopulmonary development in CDH and the identification of novel treatment targets in preclinical CDH models at the bench and their translation to clinical trials at the bedside.

Comprehensive meta-analysis of surgical procedure for congenital diaphragmatic hernia: thoracoscopic versus open repair.

PURPOSE: Previous studies have shown a higher recurrence rate and longer operative times for thoracoscopic repair (TR) of congenital diaphragmatic hernia (CDH) compared to open repair (OR). An updated meta-analysis was conducted to re-evaluate the surgical outcomes of TR. METHODS: A comprehensive literature search comparing TR and OR in neonates was performed in accordance with the PRISMA statement (PROSPERO: CRD42020166588). RESULTS: Fourteen studies were selected for quantitative analysis, including a total of 709 patients (TR: 308 cases, OR: 401 cases). The recurrence rate was higher [Odds ratio: 4.03, 95% CI (2.21, 7.36), p < 0.001] and operative times (minutes) were longer [Mean Difference (MD): 43.96, 95% CI (24.70, 63.22), p < 0.001] for TR compared to OR. A significant reduction in the occurrence of postoperative bowel obstruction was observed in TR (5.0%) compared to OR (14.8%) [Odds ratio: 0.42, 95% CI (0.20, 0.89), p = 0.02]. CONCLUSIONS: TR remains associated with higher recurrence rates and longer operative times. However, the reduced risk of postoperative bowel obstruction suggests potential long-term benefits. This study emphasizes the importance of meticulous patient selection for TR to mitigate detrimental effects on patients with severe disease.

The brain of fetuses with congenital diaphragmatic hernia shows signs of hypoxic injury with loss of progenitor cells, neurons, and oligodendrocytes.

Congenital diaphragmatic hernia (CDH) is a birth defect characterized by incomplete closure of the diaphragm, herniation of abdominal organs into the chest, and compression of the lungs and the heart. Besides complications related to pulmonary hypoplasia, 1 in 4 survivors develop neurodevelopmental impairment, whose etiology remains unclear. Using a fetal rat model of CDH, we demonstrated that the compression exerted by herniated organs on the mediastinal structures results in decreased brain perfusion on ultrafast ultrasound, cerebral hypoxia with compensatory angiogenesis, mature neuron and oligodendrocyte loss, and activated microglia. In CDH fetuses, apoptosis was prominent in the subventricular and subgranular zones, areas that are key for neurogenesis. We validated these findings in the autopsy samples of four human fetuses with CDH compared to age- and sex-matched controls. This study reveals the molecular mechanisms and cellular changes that occur in the brain of fetuses with CDH and creates opportunities for therapeutic targets.

Core Outcome Set for Necrotizing Enterocolitis Treatment Trials.

BACKGROUND AND OBJECTIVES: Variability in outcome reporting in necrotizing enterocolitis (NEC) treatment trials hinders conducting meta-analyses and implementing novel treatments. We aimed to develop a core outcome set (COS) for NEC treatment trials including outcome measures most relevant to patients and physicians, from NEC diagnosis to adulthood. METHODS: Clinicians and/or researchers from low-middle- and high-income countries were approached based on their scientific contributions to NEC literature, and patients and parents through local organizations. We presented participants with 45 outcomes used in NEC research, identified through a systematic review. To achieve consensus, outcomes were rated on a scale of 1 to 9 in 3 online Delphi rounds, and discussed at a final consensus meeting. RESULTS: Seventy-one participants from 25 countries completed all Delphi rounds, including 15 patients and family representatives. Thirteen outcomes reached consensus in one of the stakeholder groups and were included in the consensus meeting, 6 outcomes reached consensus in both groups. Twenty-seven participants from both high- and low-middle-income countries attended the online consensus meeting, including family representatives and NEC patients. After discussion and a final vote, 5 outcomes reached consensus to be included: mortality, NEC-related mortality, short bowel syndrome, quality of life, and neurodevelopmental impairment. CONCLUSIONS: This NEC COS includes 5 predominantly long-term outcomes agreed upon by clinicians, patients, and family representatives. Use of this international COS will help standardize outcome selection in clinical trials, ensure these are relevant to those most affected by NEC care, and, ultimately, improve the care of infants with NEC.

iPSC-derived healthy human astrocytes selectively load miRNAs targeting neuronal genes into extracellular vesicles.

Astrocytes are in constant communication with neurons during the establishment and maturation of functional networks in the developing brain. Astrocytes release extracellular vesicles (EVs) containing microRNA (miRNA) cargo that regulates transcript stability in recipient cells. Astrocyte released factors are thought to be involved in neurodevelopmental disorders. Healthy astrocytes partially rescue Rett Syndrome (RTT) neuron function. EVs isolated from stem cell progeny also correct aspects of RTT. EVs cross the blood-brain barrier (BBB) and their cargo is found in peripheral blood which may allow non-invasive detection of EV cargo as biomarkers produced by healthy astrocytes. Here we characterize miRNA cargo and sequence motifs in healthy human astrocyte derived EVs (ADEVs). First, human induced Pluripotent Stem Cells (iPSC) were differentiated into Neural Progenitor Cells (NPCs) and subsequently into astrocytes using a rapid differentiation protocol. iPSC derived astrocytes expressed specific markers, displayed intracellular calcium transients and secreted ADEVs. miRNAs were identified by RNA-Seq on astrocytes and ADEVs and target gene pathway analysis detected brain and immune related terms. The miRNA profile was consistent with astrocyte identity, and included approximately 80 miRNAs found in astrocytes that were relatively depleted in ADEVs suggestive of passive loading. About 120 miRNAs were relatively enriched in ADEVs and motif analysis discovered binding sites for RNA binding proteins FUS, SRSF7 and CELF5. miR-483-5p was the most significantly enriched in ADEVs. This miRNA regulates MECP2 expression in neurons and has been found differentially expressed in blood samples from RTT patients. Our results identify potential miRNA biomarkers selectively sorted into ADEVs and implicate RNA binding protein sequence dependent mechanisms for miRNA cargo loading.

Antenatal Administration of Extracellular Vesicles Derived From Amniotic Fluid Stem Cells Improves Lung Function in Neonatal Rats With Congenital Diaphragmatic Hernia.

BACKGROUND: The severity of pulmonary hypoplasia is a main determinant of outcome for babies with congenital diaphragmatic hernia (CDH). Antenatal administration of extracellular vesicles derived from amniotic fluid stem cells (AFSC-EVs) has been shown to rescue morphological features of lung development in the rat nitrofen model of CDH. Herein, we evaluated whether AFSC-EV administration to fetal rats with CDH is associated with neonatal improvement in lung function. METHODS: AFSC-EVs were isolated by ultracentrifugation and characterized by size, morphology, and canonical marker expression. At embryonic (E) day 9.5, dams were gavaged with olive oil (control) or nitrofen to induce CDH. At E18.5, fetuses received an intra-amniotic injection of either saline or AFSC-EVs. At E21.5, rats were delivered and subjected to a tracheostomy for mechanical ventilation (flexiVent system). Groups were compared for lung compliance, resistance, Newtonian resistance, tissue damping and elastance. Lungs were evaluated for branching morphogenesis and collagen quantification. RESULTS: Compared to healthy control, saline-treated pups with CDH had fewer airspaces, more collagen deposition, and functionally exhibited reduced compliance and increased airway resistance, elastance, and tissue damping. Conversely, AFSC-EV administration resulted in improvement of lung mechanics (compliance, resistance, tissue damping, elastance) as well as lung branching morphogenesis and collagen deposition. CONCLUSIONS: Our studies show that the rat nitrofen model reproduces lung function impairment similar to that of human babies with CDH. Antenatal administration of AFSC-EVs improves lung morphology and function in neonatal rats with CDH. LEVEL OF EVIDENCE: N/A (animal and laboratory study).

Neonatal Intestinal Segmental Volvulus: What Are the Differences with Midgut Volvulus?

OBJECTIVE: Intestinal volvulus in the neonate is a surgical emergency caused by either midgut volvulus (MV) with intestinal malrotation or less commonly, by segmental volvulus (SV) without intestinal malrotation. The aim of our study was to investigate if MV and SV can be differentiated by clinical course, intraoperative findings, and postoperative outcomes. METHODS: Using a defined search strategy, two investigators independently identified all studies comparing MV and SV in neonates. PRISMA guidelines were followed, and a meta-analysis was performed using RevMan 5.3. RESULTS: Of 1,026 abstracts screened, 104 full-text articles were analyzed, and 3 comparative studies were selected (112 patients). There were no differences in gestational age (37 vs. 36 weeks), birth weight (2,989 vs. 2,712 g), and age at presentation (6.9 vs. 3.8 days). SV was more commonly associated with abnormal findings on fetal ultrasound (US; 65 vs. 11.6%; p < 0.00001). Preoperatively, SV was more commonly associated with abdominal distension (32 vs. 77%; p < 0.05), whereas MV with a whirlpool sign on ultrasound (57 vs. 3%; p < 0.01). Bilious vomiting had similar incidence in both (88 ± 4% vs. 50 ± 5%). Intraoperatively, SV had a higher incidence of intestinal atresia (2 vs. 19%; p < 0.05) and need for bowel resection (13 vs. 91%; p < 0.00001). There were no differences in postoperative complications (13% MV vs. 14% SV), short bowel syndrome (15% MV vs. 0% SV; data available only from one study), and mortality (12% MV vs. 2% SV). CONCLUSION: Our study highlights the paucity of studies on SV in neonates. Nonetheless, our meta-analysis clearly indicates that SV is an entity on its own with distinct clinical features and intraoperative findings that are different from MV. SV should be considered as one of the differential diagnoses in all term and preterm babies with bilious vomiting after MV was ruled out-especially if abnormal fetal US and abdominal distension is present.

Diagnosis and management of congenital diaphragmatic hernia: a 2023 update from the Canadian Congenital Diaphragmatic Hernia Collaborative.

OBJECTIVE: The Canadian Congenital Diaphragmatic Hernia (CDH) Collaborative sought to make its existing clinical practice guideline, published in 2018, into a 'living document'. DESIGN AND MAIN OUTCOME MEASURES: Critical appraisal of CDH literature adhering to Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Evidence accumulated between 1 January 2017 and 30 August 2022 was analysed to inform changes to existing or the development of new CDH care recommendations. Strength of consensus was also determined using a modified Delphi process among national experts in the field. RESULTS: Of the 3868 articles retrieved in our search that covered the 15 areas of CDH care, 459 underwent full-text review. Ultimately, 103 articles were used to inform 20 changes to existing recommendations, which included aspects related to prenatal diagnosis, echocardiographic evaluation, pulmonary hypertension management, surgical readiness criteria, the type of surgical repair and long-term health surveillance. Fifteen new CDH care recommendations were also created using this evidence, with most related to the management of pain and the provision of analgesia and neuromuscular blockade for patients with CDH. CONCLUSIONS: The 2023 Canadian CDH Collaborative's clinical practice guideline update provides a management framework for infants and children with CDH based on the best available evidence and expert consensus.

Anti-inflammatory effects of antenatal administration of stem cell derived extracellular vesicles in the brain of rat fetuses with congenital diaphragmatic hernia.

PURPOSE: Congenital diaphragmatic hernia (CDH) survivors may experience neurodevelopmental impairment, whose etiology remains elusive. Preclinical evidence indicates that amniotic fluid stem cell extracellular vesicle (AFSC-EV) administration promotes lung development but their effects on other organs are unknown. Herein, we investigated the brain of rat fetuses with CDH for signs of inflammation and response to AFSC-EVs. METHODS: CDH was induced by maternal nitrofen administration at E9.5. At E18.5, fetuses were injected intra-amniotically with saline or AFSC-EVs (isolated by ultracentrifugation, characterized as per MISEV guidelines). Fetuses from vehicle-gavaged dams served as controls. Groups were compared for: lung hypoplasia, TNFa and IL-1B brain expression, and activated microglia (Iba1) density in the subgranular zone (SGZ). RESULTS: CDH lungs had fewer airspaces compared to controls, whereas AFSC-EV-treated lungs had rescued branching morphogenesis. Fluorescently labeled AFSC-EVs injected intra-amniotically into CDH fetuses had fluorescent signal in the brain. Compared to controls, the brain of CDH fetuses had higher TNFa and IL-1B levels, and increased activated microglia density. Conversely, the brain of AFSC-EV treated fetuses had inflammatory marker expression levels and microglia density similar to controls. CONCLUSION: This study shows that the brain of rat fetuses with CDH has signs of inflammation that are abated by the intra-amniotic administration of AFSC-EVs.

Characterization of the congenital diaphragmatic hernia model in C57BL/6J fetal mice: a step toward lineage tracing experiments.

PURPOSE: Lineage tracing is key to study the fate of individual cells and their progeny especially in developmental biology. To conduct these studies, we aimed to establish a reproducible model of CDH in the most commonly used genetic background strain that is C57BL/6J mice. METHODS: CDH was induced in C57BL/6J dams by maternal administration of nitrofen + bisdiamine at E8.5. Fetuses from olive oil-gavaged mothers served as controls. Lungs from CDH and control fetuses were compared for (1) growth via radial airspace count (RAC), mean linear intercept (MLI) and gene expression for Fgf10, Nrp1, and Ctnnb1; (2) maturation (Pdpn, Spc, Ager, Abca3, Eln, Acta2, Pdgfra) via gene and protein expression; (3) vascularization via gene and protein expression (CD31, Vegfa, Vegfr1/2, Epas1, Enos). STATISTICS: unpaired t-test or Mann-Whitney test. RESULTS: Nitrofen + bisdiamine administration resulted in 36% left-sided CDH (31% mortality). CDH fetuses had hypoplastic lungs and impaired growth (lower RAC, higher MLI, lower Fgf10, Nrp1, Ctnnb1), maturation (decreased Pdpn, Ager, Eln gene expression), and vascularization (decreased Cd31, Vegfr1/2; Epas1 and Enos). Lower protein expression was confirmed for PDPN, ELN and CD31. CONCLUSION: Modeling CDH in C57BL/6J mouse fetuses is effective in reproducing the classical CDH hallmarks. This model will be critical for lineage tracing experiments.

Beyond the diaphragm and the lung: a multisystem approach to understanding congenital diaphragmatic hernia.

Congenital diaphragmatic hernia (CDH) is a birth defect characterized by the incomplete closure of the diaphragm and herniation of abdominal organs into the chest during gestation. This invariably leads to an impairment in fetal lung development (pulmonary hypoplasia) that involves the pulmonary vessels (vascular remodeling) leading to postnatal pulmonary hypertension. Moreover, approximately 60% of CDH survivors have long-term comorbidities, including critical cardiac anomalies, neurodevelopmental impairment, gastroesophageal reflux, and musculoskeletal malformations. While the pathophysiology of the diaphragmatic defect and pulmonary hypoplasia have been studied in detail over the decades, less is known about the other organs affected in CDH. In this review, we searched the literature for reports on other organs beyond the lung and diaphragm in human and experimental models of CDH. We found studies reporting gross morphometric changes and alterations to biological pathways in the heart, brain, liver, kidney, gastrointestinal tract, and musculoskeletal system. Given the paucity of literature and the importance that these comorbidities play in the life of patients with CDH, further studies are needed to comprehensively uncover the pathophysiology of the changes observed in these other organs.

Development of an international core outcome set for treatment trials in necrotizing enterocolitis-a study protocol.

AIM: Necrotizing enterocolitis (NEC) is the most lethal disease of the gastrointestinal tract of preterm infants. New and existing management strategies need clinical evaluation. Large heterogeneity exists in the selection, measurement, and reporting of outcome measures in NEC intervention studies. This hampers meta-analyses and the development of evidence-based management guidelines. We aim to develop a Core Outcome Set (COS) for NEC that includes the most relevant outcomes for patients and physicians, from moment of diagnosis into adulthood. This COS is designed for use in NEC treatment trials, in infants with confirmed NEC. METHODS: This study is designed according to COS-STAD (Core Outcome Set-STAndards for Development) recommendations and the COMET (Core Outcome Measures in Effectiveness Trials) Initiative Handbook. We obtained a waiver from the Ethics Review Board and prospectively registered this study with COMET (Study 1920). We will approach 125 clinicians and/or researchers from low-middle and high-income countries based on their scientific output (using SCIVAL, a bibliometric tool). Patients and parents will be approached through local patient organisations. Participants will be separated into three panels, to assess differences in priorities between former patients and parents (1. lay panel), clinicians and researchers involved in the neonatal period (2. neonatal panel) and after the neonatal period (3. post-neonatal panel). They will be presented with outcomes currently used in NEC research, identified through a systematic review, in a Delphi process. Eligible outcome domains are also identified from the patients and parents' perspectives. Using a consensus process, including three online Delphi rounds and a final face-to-face consensus meeting, the COS will be finalised and include outcomes deemed essential to all stakeholders: health care professionals, parents and patients' representatives. The final COS will be reported in accordance with the COS-Standards for reporting (COS-STAR) statement. CONCLUSIONS: Development of an international COS will help to improve homogeneity of outcome measure reporting in NEC, will enable adequate and efficient comparison of treatment strategies, and will help the interpretation and implementation of clinical trial results. This will contribute to high-quality evidence regarding the best treatment strategy for NEC in preterm infants.

A Tracheal Aspirate-derived Airway Basal Cell Model Reveals a Proinflammatory Epithelial Defect in Congenital Diaphragmatic Hernia.

Rationale: Congenital diaphragmatic hernia (CDH) is characterized by incomplete closure of the diaphragm and lung hypoplasia. The pathophysiology of lung defects in CDH is poorly understood. Objectives: To establish a translational model of human airway epithelium in CDH for pathogenic investigation and therapeutic testing. Methods: We developed a robust methodology of epithelial progenitor derivation from tracheal aspirates of newborns. Basal stem cells (BSCs) from patients with CDH and preterm and term non-CDH control subjects were derived and analyzed by bulk RNA sequencing, assay for transposase accessible chromatin with sequencing, and air-liquid interface differentiation. Lung sections from fetal human CDH samples and the nitrofen rat model of CDH were subjected to histological assessment of epithelial defects. Therapeutics to restore epithelial differentiation were evaluated in human epithelial cell culture and the nitrofen rat model of CDH. Measurements and Main Results: Transcriptomic and epigenetic profiling of CDH and control BSCs reveals a proinflammatory signature that is manifested by hyperactive nuclear factor kappa B and independent of severity and hernia size. In addition, CDH BSCs exhibit defective epithelial differentiation in vitro that recapitulates epithelial phenotypes found in fetal human CDH lung samples and fetal tracheas of the nitrofen rat model of CDH. Furthermore, blockade of nuclear factor kappa B hyperactivity normalizes epithelial differentiation phenotypes of human CDH BSCs in vitro and in nitrofen rat tracheas in vivo. Conclusions: Our findings have identified an underlying proinflammatory signature and BSC differentiation defects as a potential therapeutic target for airway epithelial defects in CDH.

Seasonal Variation of Congenital Diaphragmatic Hernia: A Review of the Literature and Database Report from the United States and Canada.

INTRODUCTION: The etiology of congenital diaphragmatic hernia (CDH) remains unknown and only 10 to 30% of patients have a genetic cause. Seasonal variation is known to contribute to the development of some congenital anomalies. Our aim was to investigate whether CDH births have seasonal variation. MATERIALS AND METHODS: A literature review was conducted for CDH and seasonality. Moreover, data from the CDH International Patient Registry Database were collected for infants with due dates between 2008 and 2014. Due dates were used to determine seasonal distribution of births. Birth rates per month in the United States and Canada were extracted from publicly available databases. Data were analyzed using analysis of variance and contingency tables. RESULTS: First, the literature review revealed 11 articles, of which 3 were eligible for inclusion. These studies reported conflicting results on seasonality of CDH. Second, we extracted due dates from the CDH International Patient Registry Database (1,259 patients) and found that there were fewer due dates in winter months (12.1 ± 4 patients/month) than in summer (16.7 ± 6 patients/month; p = 0.011) and fall months (16.3 ± 5 patients/month; p = 0.022). Although this trend was similar to that of all births in the United States and Canada, a lower incidence was observed in winter for CDH infants (20.2%) than for the general population (24.1%, p = 0.0012). CDH survival rate did not vary by season. CONCLUSION: This study provides evidence for a seasonal variation of CDH births. No causative link was established between CDH development and seasonality. Population-based studies with a focus on exposome data are needed to explain seasonal variation in CDH.

Congenital lung malformations: Dysregulated lung developmental processes and altered signaling pathways.

Congenital lung malformations comprise a diverse group of anomalies including congenital pulmonary airway malformation (CPAM, previously known as congenital cystic adenomatoid malformation or CCAM), bronchopulmonary sequestration (BPS), congenital lobar emphysema (CLE), bronchogenic cysts, and hybrid lesions. Little is known about the signaling pathways that underlie the pathophysiology of these lesions and the processes that may promote their malignant transformation. In the last decade, the use of transgenic/knockout animal models and the implementation of next generation sequencing on surgical lung specimens have increased our knowledge on the pathophysiology of these lesions. Herein, we provide an overview of normal lung development in humans and rodents, and we discuss the current state of knowledge on the pathophysiology and molecular pathways that are altered in each congenital lung malformation.