Nasal expression of SARS-CoV-2 entry receptors in newborns.

Background: SARS-CoV-2 infection is typically mild in children. Lower expression of SARS-CoV-2 entry receptors in the nasal epithelia have been described in children compared with adults. However, data from newborns are lacking.

Glucocorticoids, sodium transport mediators, and respiratory distress syndrome in preterm infants.

Background: Antenatal glucocorticoids (GCs) reduce respiratory distress syndrome (RDS) in preterm infants and are associated with reduced lung liquid content. Our aim was to assess whether airway gene expression of mediators of pulmonary epithelial sodium and liquid absorption, and further, respiratory morbidity, associate with cord blood GC concentrations.

Methods: The study included 64 infants delivered <32 weeks gestation.

Postnatal gene expression of airway epithelial sodium transporters associated with birth stress in humans.

Introduction: Lung fluid clearance is essential for successful postnatal pulmonary adaptation. The epithelial sodium channel (ENaC) and Na-K-ATPase, induced by serum- and glucocorticoid-inducible kinase 1 (SGK1) as well as aquaporins (AQP), represent key players in the switch from fetal lung fluid secretion to absorption and in early postnatal lung fluid balance. Birth stress, including a surge in catecholamines, promotes pulmonary adaptation, likely through the augmentation of epithelial sodium reabsorption.

Inhibition of Regulatory-Associated Protein of Mechanistic Target of Rapamycin Prevents Hyperoxia-Induced Lung Injury by Enhancing Autophagy and Reducing Apoptosis in Neonatal Mice.

Administration of supplemental oxygen remains a critical clinical intervention for survival of preterm infants with respiratory failure. However, prolonged exposure to hyperoxia can augment pulmonary damage, resulting in developmental lung diseases embodied as hyperoxia-induced acute lung injury and bronchopulmonary dysplasia (BPD). We sought to investigate the role of autophagy in hyperoxia-induced apoptotic cell death in developing lungs.

Lung Ultrasound and Static Lung Compliance during Postnatal Adaptation in Healthy Term Infants.

Background: B-lines in lung ultrasound can be used to estimate lung liquid. B-lines are ring-down artifacts that arise from alterations to subpleural lung parenchyma. Lung ultrasound has been used to differentiate between diseases causing respiratory symptoms in neonates.

Duration of gestation and mode of delivery affect the genes of transepithelial sodium transport in pulmonary adaptation.

Background: Respiratory distress due to inadequate lung liquid clearance is a significant problem in infants delivered late preterm or early term, especially by elective cesarean delivery (CD). Lung liquid clearance depends on epithelial ion transport and in animals is induced by glucocorticoids.

Objectives: In newborn late preterm and term infants to study airway epithelial gene expressions of epithelial sodium channel (ENaC), and the serum and glucocorticoid-inducible kinase 1 (SGK1), and their association with cortisol, mode of delivery, and gestational age (GA).

Antenatal betamethasone associates with transient immunodepression in very low birth weight infants.

Background: Antenatal betamethasone (BM) treatment for mothers at risk for premature delivery is effective in reducing neonatal morbidity. Immunodepression, defined as monocyte human leukocyte antigen (HLA)-DR expression <60%, is common in patients in intensive care. In very low birth weight (VLBW) infants, immunodepression correlates with gestational age and may predispose to infections.

Delayed lung liquid absorption after cesarean section at term.

Background: Delayed postnatal removal of lung liquid may result in respiratory distress, which is more common in infants born by cesarean section. Vertical artefacts (B-lines) arising from the lung surface in lung ultrasound have been shown to correlate with the liquid content of the lungs.

Objectives: We studied whether lung ultrasound could be used for the assessment of postnatal lung liquid in healthy term infants born vaginally and by cesarean section.

Hyperoxia and interferon-γ-induced injury in developing lungs occur via cyclooxygenase-2 and the endoplasmic reticulum stress-dependent pathway.

We noted a marked increase in cyclooxygenase-2 (Cox2) and the activation of the endoplasmic reticulum (ER) stress pathway in newborn murine lung on exposure to hyperoxia and IFN-γ. We sought to evaluate Cox2-mediated ER stress pathway activation in hyperoxia-induced and IFN-γ-mediated injury in developing lungs. We applied in vivo genetic gain-of-function and genetic/chemical inhibition, as well as in vitro loss-of-function genetic strategies.

Low monocyte HLA-DR expression as an indicator of immunodepression in very low birth weight infants.

Background: As a protective response to an inflammatory stimulus, the antigen-presenting molecules (human leukocyte antigen-DR (HLA-DR)) on monocytes are downregulated. If severe, the response may lead to immunodepression or immunoparalysis, associated with an increased rate of morbidity and mortality in adults. In very low birth weight (VLBW) infants, birth and intensive care present major immunological challenges.

High tissue factor in lungs and plasma associates with respiratory morbidity in preterm infants.

Aim: In preterm infants, inflammation and intra-alveolar fibrin formation characterize respiratory distress syndrome (RDS). Tissue factor (TF) is a link between inflammation and coagulation pathways. We investigated the relationship between TF and cytokines in preterm infants to gain information of the role of TF in the inflammatory response.

Airway expression of the epithelial sodium channel α-subunit correlates with cortisol in term newborns.

Background: Glucocorticoids have profound effects on lung maturation and function. In in vitro and animal models, they induce epithelial sodium channels (ENaCs) in the airway epithelium, a process that is important to perinatal lung fluid clearance.

Objective: The objective of this study was to determine whether, in newborn infants, airway ENaC expression is associated with cortisol concentrations.

Expression of airway epithelial sodium channel in the preterm infant is related to respiratory distress syndrome but unaffected by repeat antenatal beta-methasone.

Background: The airway epithelial sodium channel (ENaC) is rate limiting for postnatal alveolar fluid clearance. Increased lung water content is a feature of respiratory distress syndrome (RDS), which is reduced by antenatal corticosteroid treatment in preterm infants.

Objectives: Since corticosteroids also induce ENaC gene expression, we studied whether a repeat dose of antenatal beta-methasone affects postnatal expression of airway ENaC.

Pulmonary fluid balance in the human newborn infant.

At birth, the infant's lungs must be cleared of fetal lung fluid. This process is mediated through the activation of airway epithelial sodium channels (ENaC). In animals, ENaC is considered crucial for postnatal pulmonary adaptation.

Expression of the epithelial sodium channel in airway epithelium of newborn infants depends on gestational age.

Objective: In the newborn infant, removal of fetal lung liquid from the airways depends on ion transport through the airway epithelium. The epithelial sodium channel is considered rate limiting for the postnatal clearance of lung liquid, but it is unknown whether during the early postnatal period the expression of epithelial sodium channel is associated with maturity. Our objective was to study the relationship between gestational age and epithelial sodium channel expression in airway epithelium.