Fetal hypoplastic lungs have multilineage inflammation that is reversed by amniotic fluid stem cell extracellular vesicle treatment

Epithelial Dysfunction in Congenital Diaphragmatic Hernia: Mechanisms, Models and Emerging Therapies

Congenital diaphragmatic hernia (CDH) is a complex disorder whereby improper formation of the diaphragm allows herniation of the internal organs into the thoracic cavity, resulting in pulmonary hypoplasia among other complications. Although epithelial dysfunction is central to CDH pathology, relatively little attention has been paid to the underlying mechanisms orchestrating epithelial malfunction. Proinflammatory signaling downstream of impaired mechanotransduction due to in utero lung compression has been elucidated to drive epithelial cell phenotypes. This has been illustrated by a reduction in nuclear YAP and the upregulation of NF-kB in CDH models. In this review, we draw from recent findings using emerging technologies to examine epithelial cell mechanisms in CDH and discuss the role of compression as a central and, crucially, sufficient driver of CDH phenotypes. In recognition of the limitations of using genetic knockout models to recapitulate such a heterogenic and etiologically complicated disease, we discuss alternative models such as the established nitrofen rat model, air-liquid interface (ALI) cultures, organoids and ex vivo lung explants. Throughout, we acknowledge the importance of involving mechanical compression in the modeling of CDH in order to faithfully recapitulate the disease. Finally, we explore novel therapeutic strategies from stem cell and regenerative therapies to precision medicine and the importance of defining CDH endotypes in order to guide treatments.

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.

Amniotic fluid stem cell extracellular vesicles as a novel fetal therapy for pulmonary hypoplasia: a review on mechanisms and translational potential

Disruption of developmental processes affecting the fetal lung leads to pulmonary hypoplasia. Pulmonary hypoplasia results from several conditions including congenital diaphragmatic hernia (CDH) and oligohydramnios. Both entities have high morbidity and mortality, and no effective therapy that fully restores normal lung development. Hypoplastic lungs have impaired growth (arrested branching morphogenesis), maturation (decreased epithelial/mesenchymal differentiation), and vascularization (endothelial dysfunction and vascular remodeling leading to postnatal pulmonary hypertension). Herein, we discuss the pathogenesis of pulmonary hypoplasia and the role of microRNAs (miRNAs) during normal and pathological lung development. Since multiple cells and pathways are altered, the ideal strategy for hypoplastic lungs is to deliver a therapy that addresses all aspects of abnormal lung development. In this review, we report on a novel regenerative approach based on the administration of extracellular vesicles derived from amniotic fluid stem cells (AFSC-EVs). Specifically, we describe the effects of AFSC-EVs in rodent and human models of pulmonary hypoplasia, their mechanism of action via release of their cargo, including miRNAs, and their anti-inflammatory properties. We also compare cargo contents and regenerative effects of EVs from AFSCs and mesenchymal stromal cells (MSCs). Overall, there is compelling evidence that antenatal administration of AFSC-EVs rescues multiple features of fetal lung development in experimental models of pulmonary hypoplasia. Lastly, we discuss the steps that need to be taken to translate this promising EV-based therapy from the bench to the bedside. These include strategies to overcome barriers commonly associated with EV therapeutics and specific challenges related to stem cell-based therapies in fetal medicine.

Extracellular Vesicles: Advanced Tools for Disease Diagnosis, Monitoring, and Therapies

Extracellular vesicles (EVs) are a heterogeneous group of membrane-encapsulated vesicles released by cells into the extracellular space. They play a crucial role in intercellular communication by transporting bioactive molecules such as proteins, lipids, and nucleic acids. EVs can be detected in body fluids, including blood plasma, urine, saliva, amniotic fluid, breast milk, and pleural ascites. The complexity and diversity of EVs require a robust and standardized approach. By adhering to standardized protocols and guidelines, researchers can ensure the consistency, purity, and reproducibility of isolated EVs, facilitating their use in diagnostics, therapies, and research. Exosomes and microvesicles represent an exciting frontier in modern medicine, with significant potential to transform the diagnosis and treatment of various diseases with an important role in personalized medicine and precision therapy. The primary objective of this review is to provide an updated analysis of the significance of EVs by highlighting their mechanisms of action and exploring their applications in the diagnosis and treatment of various diseases. Additionally, the review addresses the existing limitations and future potential of EVs, offering practical recommendations to resolve current challenges and enhance their viability for clinical use. This comprehensive approach aims to bridge the gap between EV research and its practical application in healthcare.

Sex-specific differences in the severity of pulmonary hypoplasia in experimental congenital diaphragmatic hernia and implications for extracellular vesicle-based therapy

PURPOSE

Amniotic fluid stem cell extracellular vesicles (AFSC-EVs) hold regenerative potential to treat hypoplastic lungs secondary to congenital diaphragmatic hernia (CDH). This study aims to investigate sex-specific differences in pulmonary hypoplasia severity and responses to AFSC-EV administration in an experimental CDH mouse model.

METHODS

C57BL/6J dams were fed with nitrofen + bisdiamine (left-sided CDH) or olive oil only (control) at embryonic day (E) 8.5. Lungs were dissected (E18.5), grown ex vivo and treated with medium ± AFSC-EVs that were collected via ultracentrifugation and characterized (nanoparticle tracking analysis, electron microscopy, Western blotting). Pulmonary hypoplasia was assessed via mean linear intercept (MLI). Gene and protein expression changes (Cd31, Enos, Il1b, TNFa) were measured via RT-qPCR and immunofluorescence. Pups were genotyped for Sry.

RESULTS

Experimental CDH showed a male predominance without sex differences for pulmonary hypoplasia severity, fetal lung vascularization, and inflammation. AFSC-EV administration led to improved lung growth (decreased MLI), improved fetal lung vascularization (increased Cd31 and Enos), and decreased fetal lung inflammation (Il1b, TNFa). There was no sex-specific response to AFSC-EV administration.

CONCLUSION

This study shows sex-independent impaired lung growth, vascularization and fetal lung inflammation in a CDH mouse model. Antenatal administration of AFSC-EVs reverses aspects of pulmonary hypoplasia secondary to CDH independent of the biological sex.