Necrotizing enterocolitis (NEC) is a devastating intestinal disease primarily affecting preterm neonates and causing high morbidity, high mortality, and huge costs for the family and society. The ...treatment and the outcome of the disease have not changed in recent decades. Emerging evidence has shown that stimulating the Wnt/β-catenin pathway and enhancing intestinal regeneration are beneficial in experimental NEC, and that they could potentially be used as a novel treatment. Amniotic fluid stem cells (AFSC) and AFSC-derived extracellular vesicles (EV) can be used to improve intestinal injury in experimental NEC. However, the mechanisms by which they affect the Wnt/β-catenin pathway and intestinal regeneration are unknown. In our current study, we demonstrated that AFSC and EV attenuate NEC intestinal injury by activating the Wnt signaling pathway. AFSC and EV stimulate intestinal recovery from NEC by increasing cellular proliferation, reducing inflammation and ultimately regenerating a normal intestinal epithelium. EV administration has a rescuing effect on intestinal injury when given during NEC induction; however, it failed to prevent injury when given prior to NEC induction. AFSC-derived EV administration is thus a potential emergent novel treatment strategy for NEC.
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.
Necrotizing enterocolitis (NEC) remains the leading cause of gastrointestinal surgical emergency in preterm neonates. Over the last five decades, a variety of experimental models have been developed ...to study the pathophysiology of this disease and to test the effectiveness of novel therapeutic strategies. Experimental NEC is mainly modeled in neonatal rats, mice and piglets. In this review, we focus on these experimental models and discuss the major advantages and disadvantages of each. We also briefly discuss other models that are not as widely used but have contributed to our current knowledge of NEC.
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.
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.
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.
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.
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.
N/A (animal and laboratory study).
What is currently known about this topic?•Pulmonary hypoplasia is a primary determinant for the impaired lung function in infants with CDH.•Impaired airway branching and abnormal lung collagen deposition directly affect lung mechanics, such as compliance and resistance.•Antenatal administration of AFSC-EVs rescues features of lung development in human and rodent models of pulmonary hypoplasia.
What new information is contained in this article?•Ventilation studies in neonatal rats with CDH reveal that the nitrofen model reproduces lung function impairment like that of human babies with CDH.•Intra-amniotic administration of AFSC-EVs in fetal rats with CDH improves not only postnatal lung branching morphogenesis and collagen levels, but also pulmonary function parameters and pCO2 blood levels.
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.
Abstract
Pulmonary hypoplasia secondary to congenital diaphragmatic hernia (CDH) is characterized by impaired branching morphogenesis and differentiation. We have previously demonstrated that ...administration of extracellular vesicles derived from rat amniotic fluid stem cells (AFSC-EVs) rescues development of hypoplastic lungs at the pseudoglandular and alveolar stages in rodent models of CDH. Herein, we tested whether AFSC-EVs exert their regenerative effects at the canalicular and saccular stages, as these are translationally relevant for clinical intervention. To induce fetal pulmonary hypoplasia, we gavaged rat dams with nitrofen at embryonic day 9.5 and demonstrated that nitrofen-exposed lungs had impaired branching morphogenesis, dysregulated signaling pathways relevant to lung development (FGF10/FGFR2, ROBO/SLIT, Ephrin, Neuropilin 1, β-catenin) and impaired epithelial and mesenchymal cell marker expression at both stages. AFSC-EVs administered to nitrofen-exposed lung explants rescued airspace density and increased the expression levels of key factors responsible for branching morphogenesis. Moreover, AFSC-EVs rescued the expression of alveolar type 1 and 2 cell markers at both canalicular and saccular stages and restored markers of club, ciliated epithelial, and pulmonary neuroendocrine cells at the saccular stage. AFSC-EV-treated lungs also had restored markers of lipofibroblasts and PDGFRA+ cells to control levels at both stages. EV tracking showed uptake of AFSC-EV RNA cargo throughout the fetal lung and an mRNA-miRNA network analysis identified that several miRNAs responsible for regulating lung development processes were contained in the AFSC-EV cargo. These findings suggest that AFSC-EV-based therapies hold potential for restoring fetal lung growth and maturation in babies with pulmonary hypoplasia secondary to CDH.
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