Immature Lung Research Articles

The fungal microbiota modulate neonatal oxygen-induced lung injury

BackgroundThe immature lungs of very preterm infants are exposed to supraphysiologic oxygen, contributing to bronchopulmonary dysplasia (BPD), a chronic lung disease that is the most common morbidity of prematurity. While the microbiota significantly influences neonatal health, the relationship between the intestinal microbiome, particularly micro-eukaryotic members such as fungi and yeast, and lung injury severity in newborns remains unknown.ResultsHere, we show that the fungal microbiota modulates hyperoxia-induced lung injury severity in very low birth weight premature infants and preclinical pseudohumanized and altered fungal colonization mouse models. Instead of fungal communities dominated by Candida and Saccharomyces, the first stool microbiomes of infants who developed BPD had less interconnected community architectures with a greater diversity of rarer fungi. After using a pseudohumanized model to show that transfer to the neonatal microbiome from infants with BPD increased the severity of lung injury, we used gain and loss of function approaches to demonstrate that modulating the extent of initial neonatal fungal colonization affected the extent of BPD-like lung injury in mice. We also identified alterations in the murine intestinal microbiome and transcriptome associated with augmented lung injury.ConclusionsThese findings demonstrate that features of the initial intestinal fungal microbiome are associated with the later development of BPD in premature neonates and exert a microbiome-driven effect that is transferable and modifiable in murine models, which suggests both causality and a potential therapeutic strategy.7tBaiGhHzrwGBbT1j3n_5hVideo

P0984 Treatment with allopurinol and low-dose azathioprine during pregnancy in patients with Inflammatory Bowel Disease. A Danish single center experience

Abstract Background Low-dose azathioprine in combination with allopurinol (LD-AZA/ALLO) is a widely used treatment option in inflammatory bowel disease (IBD). Data on pregnancy and birth outcomes from exposure to combination therapy are sparse. The aim of this study was to provide data on safety and risk for adverse pregnancy and birth outcomes in women with IBD treated with LD-AZA/ALLO at the Gastrounit, Hvidovre Hospital, Copenhagen. Methods The study was a retrospective single center study. Inclusion criteria were established IBD diagnosis and treatment with LD-AZA/ALLO (AZA 50-75 mg/ ALLO 100 mg) during conception and pregnancy between 2013-2023. Data was collected from electronic medical charts and by questionnaire to all included women. Data registered was; demographics, diagnosis, disease characteristics, disease activity, IBD medications and number of pregnancies. Pregnancy outcomes were neonatal characteristics, obstetric complications, lactation and congenital malformations, disease, infections and admission to the hospital during the first year of life. Results In all, 44 women with 62 pregnancies (one twin pregnancy) and 59 live births were included. There were 1 spontaneous and 3 provoked abortions due to genetic disorders (1 trisomy 21 and 2 spinocerebellar ataxia). Obstetric complications were present in 8 (13%) pregnancies, (1 pre-eclampsia, 1 HELLP syndrome, 6 hypertension and/or gestational diabetes mellitus). 7 (11%) women had an IBD flare during pregnancy, none resulting in obstetrical complications. 5 (9 %) children were born prematurely, 4 (7 %) had low birth weight. No congenital malformations were reported. One child was born with facial nerve paralysis and later diagnosed with hyper-IgD syndrome. 8 (14 %) were admitted to neonatal ward (hours to days), mainly due to immature lungs. During the first year of life, one child was admitted to the hospital due to COVID. One child was suspected to have an immune defect, but all symptoms and biochemical abnormalities resolved and interpreted as side effect to LD-AZA/ALLO. 5 children (9%) were treated with antibiotics due to minor infections. In total 84 % of the children were breastfed during LD-AZA/ALLO treatment. Conclusion In this large single center experience with 62 pregnancies in women treated with LD- AZA/ALLO, no malformations or indications of increased risk of complications of pregnancy and birth were observed. The majority of children were breastfed and no serious signals or complications were reported first year of life. Treatment with LD-AZA/ALLO during pregnancy and breastfeeding seems safe.

Cortisol regulates neonatal lung development via Smoothened

BackgroundNeonatal respiratory distress syndrome (NRDS), one of the main causes of neonatal death, is clinically characterized by progressive dyspnea and cyanosis 1 to 2 h after birth. Corticosteroids are commonly used to prevent NRDS in clinical. However, the protective mechanism of the corticosteroids remains largely unclear.MethodsIn this study, the simulation of the molecular docking by Autodock, in vitro binding experiments, and Sonic Hedgehog (SHH) pathway examination in cells were performed to study the directly binding of cortisol to Smoothened (SMO). To explore the effect of cortisol action on the SHH pathway on neonatal lung development, we generated a genetic mouse, in which leucine 116 (L112 in human) of SMO was mutated to alanine 116 (L116A, Smoa/a) by the CRISPR-Cas9, based on sequence differences between human and mice. Then, we performed morphological analysis, single-cell RNA sequencing (scRNA-seq) on lung tissue and fluorescence in situ hybridization (FISH).ResultsIn this study, we reported that cortisol, the endogenous glucocorticoid, inhibited the sonic hedgehog (Shh)/SMO-mediated proliferation of lung fibroblasts to maintain the normal lung development. Specifically, cortisol competed with cholesterol for binding to the cysteine-rich domain (CRD) in SMO to inhibit the activation of Shh/SMO signaling, a critical signaling known for cell proliferation. Cortisol did not inhibit the activation of SMO when L112 in its CRD was mutated to A112. Moreover, Smoa/a (L116A) mice exhibited the immature lungs in which over-proliferation of interstitial fibroblasts and reduction in the surfactant protein were evident.ConclusionTogether, these results suggested that cortisol regulated cholesterol stimulation of SMO by competitively binding to the CRD to regulate neonatal lung maturation in mice.

Respiratory Severity Score (RSS): A Predictive Tool for Successful Extubation in Preterm Neonates

Introduction: The coexistence of immature lungs, poor respiratory drive, overly compliant chest wall, and surfactant deficiency in preterm neonates, leads to dependency on mechanical ventilation during the first days of life. Respiratory Severity Score (RSS) is a readily available, simple and non-invasive extubation failure prediction tool. Objective This study aims to evaluate the utility of pre-extubation RSS as a tool for predicting successful extubation among preterms. Methods and Analysis: This was a retrospective study with a duration of two years started after obtaining clearance from the Institutional Ethics Committee. All preterm neonates ventilated in NICU were included in the study. The hospital unit number was noted and the respective patient records were procured from the hospital records department. Demographic data were recorded from the files. Pre-extubation RSS was calculated. Other findings related to clinical review such as duration of invasive and non-invasive ventilation, surfactant requirement, intraventricular hemorrhage (IVH), early and late-onset sepsis, length of hospital stay (LOS), retinopathy of prematurity (ROP), bronchopulmonary dysplasia (BPD) mortality data etc. were also recorded. The age, time of extubation and weight of those babies who underwent planned extubation were also recorded. Results: The RSS and RSS/kg were significantly higher among the neonates who failed extubation ( P < .001). The Area under curve (AUC) for RSS and RSS/kg was 0.921 and 0.85, respectively. There was a significantly higher proportion of morbidities such as late-onset sepsis ( P = .046), grade ≥3 IVH ( P = .004) and ROP ( P = .043) observed among the neonates with extubation failure. The prevalence of in-hospital mortality was observed only among neonates with extubation failure which was statistically significant ( P < .001). Conclusion: This study shows that pre-extubation RSS is an excellent tool for predicting successful extubation and is more accurate than RSS/kg. RSS could be a useful tool for clinicians to assess readiness of extubation. However, more prospective, multicentric studies are necessary to validate the generalizability of RSS.

Surgery of premature infants-Perspectives and limitations

The continuous improvement in the quality of modern perinatology, sociodemographic changes and the increasing spread of reproductive medicine have resulted in an increasing number of premature infants to be treated. The treatment of preterm infants (< 37thweek of pregnancy) and especially extremely premature infants (< 28thweek of pregnancy) is challenging due to immature organ development, which differs considerably from that of other age groups. While the fate of premature infants and especially extremely premature infants was unfavorable 100 years ago, the survival of premature infants > 1000 g has now shifted to survival in over 80% of cases [30]. The main medical problem areas of immature patients are afetal proinflammatory immune system, an immature gastrointestinal tract with reduced transport capability, an incompletely developed intestinal barrier and adeveloping intestinal flora (microbiome) as well as immature lungs, which was significantly limiting for the survival of premature infants before the development of synthetic pulmonary surfactants. Furthermore, the central nervous system (CNS), which is far from being fully developed in preterm infants, is particularly vulnerable to exogenous factors, such as inflammation, toxins and medications. In addition, the CNS requires an environment appropriate to the developmental stage of the neonate to ensure normal physiological psychomotor development in the future. The article presents the special aspects of surgery on premature infants, the indications, complications and outcome, taking the special general problems of prematurity into account. Finally, the ethical conflicts associated with the care of extremely premature infants are briefly discussed.

Moving on from clinical animal-derived surfactants to peptide-based synthetic pulmonary surfactant.

Research on lung surfactant has exerted a great impact on newborn respiratory care and significantly improved survival and outcome of preterm infants with respiratory distress syndrome (RDS) due to surfactant deficiency because of lung immaturity. Current clinical, animal-derived, surfactants are among the most widely tested compounds in neonatology However, limited availability, high production costs, and ethical concerns about using animal-derived products constitute important limitations in their universal application. Synthetic lung surfactant offers a promising alternative to animal-derived surfactant by providing improved consistency, quality and purity, availability and scalability, ease of production and lower costs, acceptance, and safety for the treatment of neonatal RDS and other lung conditions. Third-generation synthetic surfactants built around surfactant protein B (SP-B) and C (SP-C) peptide mimics stand at the forefront of innovation in neonatal pulmonary medicine, while nasal continuous positive airway pressure (nCPAP) has become the standard non-invasive respiratory support for preterm infants. nCPAP can prevent the risk of chronic lung disease (bronchopulmonary dysplasia) and reduce lung injury by avoiding intubation and mechanical ventilation, is a relatively simple technique and can be initiated safely and effectively in the delivery room. Combining nCPAP with noninvasive, preferably aerosol, delivery of synthetic lung surfactant promises to improve respiratory outcomes for preterm infants, especially in low-and-middle income countries.

“Challenging acquired pulmonary interstitial emphysema in an extreme preterm infant: A case report and review of literature”

Background Pulmonary interstitial emphysema (PIE) can occur in the immature lungs of preterm infants due to overdistension from mechanical ventilation. Case Report Preterm female infant (26 weeks of gestational age, 950 grams) born via urgent cesarean section, APGAR 1/3/6. Invasive mechanical ventilation during the first day of life transitioned to noninvasive positive pressure ventilation (NIPPV), afterward initially stable. Apnea and bradycardia noted at 20 days of life, requiring endotracheal intubation, with complementary studies showing right PIE. Progressive emphysema deterioration, air trapping, and left lung atelectasis, with hemodynamic repercussion despite positioning, high-frequency oscillatory ventilation, and hemodynamic support with dopamine and dobutamine. Selective left intubation attempted positioning the infant, unsuccessful. Due to failure of conventional therapies and impossibility to achieve selective intubation, pediatric surgery performed endobronchial balloon occlusion with angioplasty balloon inflated with contrast with fluoroscopy control. Progressive improvement, weaning ventilatory settings with acceptable oxygenation. Balloon was retired after 5 days. Mechanical ventilation was discontinued at 52 days of life. Infant was discharged without respiratory support nor oxygen at 100 days of life. Conclusions PIE treatment is based in conventional measures (respiratory support and positioning) but eventually might require alternative techniques when the first fail, with limited work in pediatric population and further technical limitations in the preterm infants.

Perinatal Inflammation Results in Sex-Dependent Cardiac Dysfunction.

An increased incidence of adult-onset heart failure is seen in individuals born preterm or affected by fetal growth restriction. An adverse maternal environment is associated with both preterm birth and poor fetal development, and postnatal oxygen therapy is frequently required to sustain oxygenation of vulnerable tissues due to lung immaturity. Studies using our murine model of maternal inflammation (LPS) and neonatal hyperoxia exposure (O2) observed pathological changes in cardiac structural proteins and functional analysis with sex dependent differences in pathologies at 10 months of age. Using our previous model, the current investigations tested the hypothesis that early-life perturbations in cardiac structural proteins might predict adult cardiac dysfunction in a sex dependent manner. LPS-exposed females had lower αMHC mRNA and protein at P0 and P7 relative to the saline-exposed females, but these changes did not persist. Male mice exposed to LPS/O2 had normal expression of αMHC mRNA and protein compared to saline/room air controls though P56, when they dramatically increased. Correlative changes were observed in left ventricular function with a more severe phenotype in the males indicating sex-based differences in cardiac adaptation. Our findings demonstrate that early changes in contractile proteins temporally correlate with deficits in cardiac contractility, with a more severe phenotype in males. Our data suggest that similar findings in humans may predict risk for disease in growth-restricted infants.

Metabolic and Microbial Dysregulation in Preterm Infants with Neonatal Respiratory Distress Syndrome: An Early Developmental Perspective.

Neonatal respiratory distress syndrome (NRDS) is one of the most severe respiratory disorders in preterm infants (PTIs) due to immature lung development. To delineate the serum metabolic alterations and gut microbiota variations in NRDS and assess their implications on neonatal development, we enrolled 13 NRDS neonates and 12 PTIs and collected fecal and serum specimens after birth. Longitudinal fecal sampling was conducted weekly for a month in NRDS neonates. NRDS neonates were characterized by notably reduced gestational ages and birth weights and a higher rate of asphyxia at birth relative to PTIs. Early postnatal disturbances in tryptophan metabolism were evident in the NRDS group, concomitant with elevated relative abundance of Haemophilus, Fusicatenibacter, and Vibrio. Integrative multiomics analyses revealed an inverse relationship between tryptophan concentrations and Blautia abundance. At one-week old, NRDS neonates exhibited cortisol regulation anomalies and augmented hepatic catabolism. Sequential microbial profiling revealed distinct gut microbiota evolution in NRDS subjects, characterized by a general reduction in potentially pathogenic bacteria. The acute perinatal stress of NRDS leads to mitochondrial compromise, hormonal imbalance, and delayed gut microbiota evolution. Despite the short duration of NRDS, its impact on neonatal development is significant and requires extended attention.

Anti-CCL2 therapy reduces oxygen toxicity to the immature lung

Oxygen toxicity constitutes a key contributor to bronchopulmonary dysplasia (BPD). Critical step in the pathogenesis of BPD is the inflammatory response in the immature lung with the release of pro-inflammatory cytokines and the influx of innate immune cells. Identification of efficient therapies to alleviate the inflammatory response remains an unmet research priority. First, we studied macrophage and neutrophil profiles in tracheal aspirates of n = 103 preterm infants <29 weeks´ gestation requiring mechanical ventilation. While no differences were present at birth, a higher fraction of macrophages, the predominance of the CD14+CD16+ subtype on day 5 of life was associated with moderate/severe BPD. Newborn CCL-2−/− mice insufficient in pulmonary macrophage recruitment had a reduced influx of neutrophils, lower apoptosis induction in the pulmonary tissue and better-preserved lung morphometry with higher counts of type II cells, mesenchymal stem cells and vascular endothelial cells when exposed to hyperoxia for 7 days. To study the benefit of a targeted approach to prevent the pulmonary influx of macrophages, wildtype mice were repeatedly treated with CCL-2 blocking antibodies while exposed to hyperoxia for 7 days. Congruent with the results in CCL-2−/− animals, the therapeutic intervention reduced the pulmonary inflammatory response, attenuated cell death in the lung tissue and better-preserved lung morphometry. Overall, our preclinical and clinical datasets document the predominant role of macrophage recruitment to the pathogenesis of BPD and establish the abrogation of CCL-2 function as novel approach to protect the immature lung from hyperoxic injury.

Initial non-invasive in vivo sensing of the lung using time domain diffuse optics

The in vivo diagnosis and monitoring of pulmonary disorders (caused for example by emphysema, Covid-19, immature lung tissue in infants) could be effectively supported by the non-invasive sensing of the lung through light. With this purpose, we investigated the feasibility of probing the lung by means of time-resolved diffuse optics, leveraging the increased depth (a few centimeters) attained by photons collected after prolonged propagation time (a few nanoseconds). We present an initial study that includes measurements performed on 5 healthy volunteers during a breathing protocol, using a time-resolved broadband diffuse optical spectroscopy system. Those measurements were carried out across the spectral range of 600–1100 nm at a source-detector distance of 3 cm, and at 820 nm over a longer distance (7–9 cm). The preliminary analysis of the in vivo data with a simplified homogeneous model revealed a maximum probing depth of 2.6–3.9 cm, suitable for reaching the lung. Furthermore, we observed variations in signal associated with respiration, particularly evident at long photon propagation times. However, challenges stemming from both intra- and inter-subject variability, along with inconsistencies potentially arising from conflicting scattering and absorption effects on the collected signal, hindered a clear interpretation. Aspects that require further investigation for a more comprehensive understanding are outlined.

Development of the terminal air spaces in the gray short-tailed opossum (Monodelphis domestica)- 3D reconstruction by microcomputed tomography.

Marsupials are born with structurally immature lungs when compared to eutherian mammals. The gray short-tailed opossum (Monodelphis domestica) is born at the late canalicular stage of lung development. Despite the high degree of immaturity, the lung is functioning as respiratory organ, however supported by the skin for gas exchange during the first postnatal days. Consequently, the majority of lung development takes place in ventilated functioning state during the postnatal period. Microcomputed tomography (μCT) was used to three-dimensionally reconstruct the terminal air spaces in order to reveal the timeline of lung morphogenesis. In addition, lung and air space volume as well as surface area were determined to assess the functional relevance of the structural changes in the developing lung. The development of the terminal air spaces was examined in 35 animals from embryonic day 13, during the postnatal period (neonate to 57 days) and in adults. At birth, the lung of Monodelphis domestica consists of few large terminal air spaces, which are poorly subdivided and open directly from short lobar bronchioles. During the first postnatal week the number of smaller terminal air spaces increases and numerous septal ridges indicate a process of subdivision, attaining the saccular stage by 7 postnatal days. The 3D reconstructions of the terminal air spaces demonstrated massive increases in air sac number and architectural complexity during the postnatal period. Between 28 and 35 postnatal days alveolarization started. Respiratory bronchioles, alveolar ducts and a typical acinus developed. The volume of the air spaces and the surface area for gas exchange increased markedly with alveolarization. The structural transformation from large terminal sacs to the final alveolar lung in the gray short-tailed opossum follows similar patterns as described in other marsupial and placental mammals. The processes involved in sacculation and alveolarization during lung development seem to be highly conservative within mammalian evolution.

Enteral supplementation with arachidonic and docosahexaenoic acid and pulmonary outcome in extremely preterm infants

Enteral supplementation with arachidonic acid (AA) and docosahexaenoic acid (DHA) in extremely preterm infants has shown beneficial effects on retinopathy of prematurity and pulmonary outcome whereas exclusive DHA supplementation has been associated with increased pulmonary morbidity. This secondary analysis evaluates pulmonary outcome in 204 extremely preterm infants, randomized to receive AA (100 mg/kg/day) and DHA (50 mg/kg/day) enterally from birth until term age or standard care. Pulmonary morbidity was primarily assessed based on severity of bronchopulmonary dysplasia (BPD). Serum levels of AA and DHA during the first 28 days were analysed in relation to BPD. Supplementation with AA:DHA was not associated with increased BPD severity, adjusted OR 1.48 (95 % CI 0.85–2.61), nor with increased need for respiratory support at post menstrual age 36 weeks or duration of oxygen supplementation. Every 1 % increase in AA was associated with a reduction of BPD severity, adjusted OR 0.73 (95 % CI 0.58–0.92). In conclusion, in this study, with limited statistical power, enteral supplementation with AA:DHA was not associated with an increased risk of pulmonary morbidity, but higher levels of AA were associated with less severe BPD. Whether AA or the combination of AA and DHA have beneficial roles in the immature lung needs further research.

In utero ventilation induces lung parenchymal and vascular alterations in extremely preterm fetal sheep.

Extremely preterm infants are often exposed to long durations of mechanical ventilation to facilitate gas exchange, resulting in ventilation-induced lung injury (VILI). New lung protective strategies utilizing noninvasive ventilation or low tidal volumes are now common but have not reduced rates of bronchopulmonary dysplasia. We aimed to determine the effect of 24 h of low tidal volume ventilation on the immature lung by ventilating preterm fetal sheep in utero. Preterm fetal sheep at 110 ± 1(SD) days' gestation underwent sterile surgery for instrumentation with a tracheal loop to enable in utero mechanical ventilation (IUV). At 112 ± 1 days' gestation, fetuses received either in utero mechanical ventilation (IUV, n = 10) targeting 3-5 mL/kg for 24 h, or no ventilation (CONT, n = 9). At necropsy, fetal lungs were collected to assess molecular and histological markers of lung inflammation and injury. IUV significantly increased lung mRNA expression of interleukin (IL)-1β, IL-6, IL-8, IL-10, and tumor necrosis factor (TNF) compared with CONT, and increased surfactant protein (SP)-A1, SP-B, and SP-C mRNA expression compared with CONT. IUV produced modest structural changes to the airways, including reduced parenchymal collagen and myofibroblast density. IUV increased pulmonary arteriole thickness compared with CONT but did not alter overall elastin or collagen content within the vasculature. In utero ventilation of an extremely preterm lung, even at low tidal volumes, induces lung inflammation and injury to the airways and vasculature. In utero ventilation may be an important model to isolate the confounding mechanisms of VILI to develop effective therapies for preterm infants requiring prolonged respiratory support.NEW & NOTEWORTHY Preterm infants often require prolonged respiratory support, but the relative contribution of ventilation to the development of lung injury is difficult to isolate. In utero mechanical ventilation allows for mechanistic investigations into ventilation-induced lung injury without confounding factors associated with sustaining extremely preterm lambs ex utero. Twenty-four hours of in utero ventilation, even at low tidal volumes, increased lung inflammation and surfactant protein expression and produced structural changes to the lung parenchyma and vasculature.

Dr. Tetsuro Fujiwara-My Memories from the Early Days of Dr. Fujiwara's Research.

This brief commentary honors Dr. Tesuro Fujiwara, the first person to treat infants with respiratory distress syndrome by instilling surfactant into their trachea. In the 1960s, mortality from RDS, which could only be treated with oxygen, was about 50 percent. Based on the physiology Fujiwara learned that lung immaturity could be treated with doses of surfactant from animals in sheep models. He then made a surfactant from cow lungs called Servanta and treated 10 infants with RDS, who all had a large improvement in oxygenation. Other new therapies, such as continuous positive airway pressure and newer infant ventilators-in combination with surfactant therapy have decreased infant mortality to less than 1% from RDS in the most recent US infant death statistics.

Energizing the Lung Vasculature in the Premature Infant to Promote Alveolar Formation

Background/Objective: Chronic lung disease of prematurity, bronchopulmonary dysplasia (BPD) occurs when infants born with underdeveloped immature lungs are forced to navigate the expansion of future air spaces, with irregular vascular formation proceeding development of BPD. Lung development has distinct and dynamic metabolic requirements. We recently identified by mass spectrometry that nicotinamide adenine dinucleotide (NAD+), generated from vitamin B3 ‘Nicotinamide’ (NAM), was significantly reduced in a hyperoxia murine model of BPD. As NAM/NAD+ are dynamic regulators of tissue regenerating neovascularization in otherdisease processes, we hypothesized that NAM/NAD+ metabolic deficiencies contribute to compromised angiogenesis formation and alveolar formation. Methods: Impact of NAM supplementation on circulating human neonatal endothelial colonyforming cells (ECFCs) were assessed for differential capillary formation properties of angiogenesis (Matrigel), migration (wound healing), proliferation (WST1 and crystal violetstaining), and mitochondrial function in normoxia and hyperoxia (85% oxygen) conditions. Results: Hyperoxia suppresses ECFC angiogenesis, while NAM supplementation in hyperoxia significantly rescued vascular networks, branched nodes, and branch points (p&lt;0.001). Wound healing assays suggest that NAM promotes cell migration in normoxia and hyperoxia (p&lt;0.0001). Although NAM increased WST1 activity in hyperoxia, crystal violet analysis determined that NAM had no impact on ECFC proliferation. Lastly, NAM significantly reduced hyperoxia induced mitochondrial oxidative stress in a dose dependent manner (p&lt;0.05). Conclusion and Clinical Implications: Lung development has specific metabolic needs during different stages of development that are disrupted by premature birth. Replenishment of NAM promotes angiogenesis and migration in hyperoxia while reducing mitochondrial activity. Future studies are necessary to explore the role of NAM/NAD+ axis in the developing lung.

Reduced number of alveoli after birth in rats exposed to iron in utero.

Clinical studies have shown that diffuse chorioamniotic hemosiderosis (DCH) is a risk factor for bronchopulmonary dysplasia (BPD). However, the details of the underlying mechanism are unknown. We focused on iron, one of the blood components that diffuses within the amniotic cavity in DCH. Specifically, we conducted a histological evaluation of its effects on fetal lung development. Iron dextran 10 mg (Fe group) or physiological saline (control group) was injected into the individual amniotic cavities of pregnant Sprague Dawley rats on gestational day 19. The pups were born naturally, and the placentas and lungs collected on postnatal days 1, 14, and 60 were subjected to histological analysis. The placenta and lungs of the Fe group on day 14 contained significantly larger numbers of iron-positive granules. Morphological analysis of the lungs showed that on day 60, the total number of alveoli was significantly lower in the Fe group (p = 0.015). Immunohistochemical staining of the lung tissue for 8-hydroxy-2'-deoxyguanosine showed that, on day 1, there were significantly more positive cells in the Fe group (p = 0.003). The number of ectodermal dysplasia 1 positive cells on day 14 was significantly increased in the Fe group (p = 0.001). These results suggest that diffuse iron deposition in immature fetal lungs increases oxidative stress and decreases the number of postnatal alveoli associated with impaired lung development.

Assessment of Skin Maturity by LED Light at Birth and Its Association With Lung Maturity: Clinical Trial Secondary Outcomes

Background Clinicians face barriers when assessing lung maturity at birth due to global inequalities. Still, strategies for testing based solely on gestational age to predict the likelihood of respiratory distress syndrome (RDS) do not offer a comprehensive approach to addressing the challenge of uncertain outcomes. We hypothesize that a noninvasive assessment of skin maturity may indicate lung maturity. Objective This study aimed to assess the association between a newborn’s skin maturity and RDS occurrence. Methods We conducted a case-control nested in a prospective cohort study, a secondary endpoint of a multicenter clinical trial. The study was carried out in 5 Brazilian urban reference centers for highly complex perinatal care. Of 781 newborns from the cohort study, 640 were selected for the case-control analysis. Newborns with RDS formed the case group and newborns without RDS were the controls. All newborns with other diseases exhibiting respiratory manifestations were excluded. Skin maturity was assessed from the newborn's skin over the sole by an optical device that acquired a reflection signal through an LED sensor. The device, previously validated, measured and recorded skin reflectance. Clinical data related to respiratory outcomes were gathered from medical records during the 72-hour follow-up of the newborn, or until discharge or death, whichever occurred first. The main outcome measure was the association between skin reflectance and RDS using univariate and multivariate binary logistic regression. Additionally, we assessed the connection between skin reflectance and factors such as neonatal intensive care unit (NICU) admission and the need for ventilatory support. Results Out of 604 newborns, 470 (73.4%) were from the RDS group and 170 (26.6%) were from the control group. According to comparisons between the groups, newborns with RDS had a younger gestational age (31.6 vs 39.1 weeks, P&lt;.001) and birth weight (1491 vs 3121 grams, P&lt;.001) than controls. Skin reflectance was associated with RDS (odds ratio [OR] 0.982, 95% CI 0.979-0.985, R2=0.632, P&lt;.001). This relationship remained significant when adjusted by the cofactors antenatal corticosteroid and birth weight (OR 0.994, 95% CI 0.990-0.998, R2=0.843, P&lt;.001). Secondary outcomes also showed differences in skin reflectance. The mean difference was 0.219 (95% CI 0.200-0.238) between newborns that required ventilatory support versus those that did not and 0.223 (95% CI 0.205-0.241) between newborns that required NICU admission versus those that did not. Skin reflectance was associated with ventilatory support (OR 0.996, 95% CI 0.992-0.999, R2=0.814, P=.01) and with NICU admission (OR 0.994, 95% CI 0.990-0.998, R2=0.867, P=.004). Conclusions Our findings present a potential marker of lung immaturity at birth using the indirect method of skin assessment. Using the RDS clinical condition and a medical device, this study demonstrated the synchrony between lung and skin maturity. Trial Registration Registro Brasileiro de Ensaios Clínicos (ReBEC) RBR-3f5bm5; https://tinyurl.com/9fb7zrdb International Registered Report Identifier (IRRID) RR2-10.1136/bmjopen-2018-027442

Fetal Type Morphologies Suggest the Presence of DICER1 Hotspot Mutations in Non-small Cell Lung Cancer.

Germline and somatic pathogenic variants (PVs) in DICER1, encoding a miRNA biogenesis protein, are associated with a wide variety of highly specific pathologic entities. The lung tumors pleuropulmonary blastoma, pulmonary blastoma (PB), and well-differentiated fetal lung adenocarcinoma (WDFLAC) are all known to harbor DICER1 biallelic variants (loss of function and/or somatic hotspot missense mutations), and all share pathologic features reminiscent of the immature lung. However, the role of DICER1 PVs in non-small cell lung cancer (NSCLC) is relatively unknown. Here, we aimed to establish the spectrum of lung pathologies associated with DICER1 hotspot PVs and to compare the mutational landscape of DICER1-mutated NSCLC with and without hotspots. We queried DNA sequencing data from 12,146 NSCLCs featuring somatic DICER1 variants. 235 (1.9%) cases harboring ≥ 1 DICER1 PV were found and 9/235 (3.8%) were DICER1 hotspot-positive cases. Histologic review of DICER1 hotspot-positive cases showed that all but one tumor were classified as within the histologic spectrum of PB/WDFLAC, whereas all the DICER1 non-hotspot double variants were classified as lung adenocarcinomas, not otherwise specified. Comparison between the mutational landscape of DICER1 hotspot-positive and hotspot-negative cases revealed a higher frequency of CTNNB1 mutations in the hotspot-positive cases (5/9 vs. 2/225; P<0.00001). We conclude that DICER1 somatic hotspots are not implicated in the most common forms of NSCLC but rather select for morphologic features of lung tumor types such as PB and WDFLAC. As a corollary, cases showing this tumor morphology should undergo testing for DICER1 variants, and if positive, genetic counseling should be considered.

Furin Regulates the Alveolarization of Neonatal Lungs in a Mouse Model of Hyperoxic Lung Injury.

Despite advances in treatment options, such as corticosteroid administration and less invasive respiratory support, bronchopulmonary dysplasia (BPD) remains an important prognostic factor in preterm infants. We previously reported that furin regulates changes in lung smooth muscle cell phenotypes, suggesting that it plays a critical role in BPD pathogenesis. Therefore, in this study, we aimed to evaluate whether it regulates the alveolarization of immature lungs through activating alveolarization-driving proteins. We first examined furin expression levels, and its functions, using an established hyperoxia-induced BPD mouse model. Thereafter, we treated mice pups, as well as primary myofibroblast cell cultures, with furin inhibitors. Finally, we administered the hyperoxia-exposed mice pups with recombinant furin. Immunofluorescence revealed the co-expression of furin with alpha-smooth muscle actin. Hyperoxia exposure for 10 d decreased alveolar formation, as well as the expression of furin and its target, IGF-1R. Hexa-D-arginine administration also significantly inhibited alveolar formation. Another furin inhibitor, decanoyl-RVKR-chloromethylketone, accumulated pro-IGF-1R, and decreased IGF-1R phosphorylation in myofibroblast primary cultures. Finally, recombinant furin treatment significantly improved alveolarization in hyperoxia-exposed mice pups. Furin regulates alveolarization in immature lungs. Therefore, this study provides novel insights regarding the involvement of furin in BPD pathogenesis, and highlights a potential treatment target for ameliorating the impact of BPD.