Amnion responses to intrauterine inflammation and effects of inhibition of TNF signaling in preterm Rhesus macaque.

Intrauterine infection/inflammation (IUI) is a frequent complication of pregnancy leading to preterm labor and fetal inflammation. How inflammation is modulated at the maternal-fetal interface is unresolved. We compared transcriptomics of amnion (a fetal tissue in contact with amniotic fluid) in a preterm Rhesus macaque model of IUI induced by lipopolysaccharide with human cohorts of chorioamnionitis. Bulk RNA sequencing (RNA-seq) amnion transcriptomic profiles were remarkably similar in both Rhesus and human subjects and revealed that induction of key labor-mediating genes such as IL1 and IL6 was dependent on nuclear factor κB (NF-κB) signaling and reversed by the anti-tumor necrosis factor (TNF) antibody Adalimumab. Inhibition of collagen biosynthesis by IUI was partially restored by Adalimumab. Interestingly, single-cell transcriptomics, flow cytometry, and immunohistology demonstrated that a subset of amnion mesenchymal cells (AMCs) increase CD14 and other myeloid cell markers during IUI both in the human and Rhesus macaque. Our data suggest that CD14+ AMCs represent activated AMCs at the maternal-fetal interface.

Respiratory benefit in preterm lambs is progressively lost when the concentration of fetal plasma betamethasone is titrated below two nanograms per milliliter.

Antenatal steroid therapy is the standard of care for women at imminent risk of preterm delivery. Current dosing regimens use suprapharmacological doses to achieve extended fetal steroid exposures. We aimed to determine the lowest fetal plasma betamethasone concentration sufficient to achieve functional preterm lung maturation. Ewes with single fetuses underwent surgery to install a fetal jugular catheter. Adopting a stepwise design, ewes were randomized to either a saline-only group (negative control group; n = 9) or one of four betamethasone treatment groups. Each betamethasone group fetus received a fetal intravenous infusion to target a constant plasma betamethasone level of either 1) 2 ng/mL (2 ng/mL positive control group, n = 9); 2) 1 ng/mL, (1 ng/mL group, n = 10); 3) 0.5 ng/mL (0.5 ng/mL group, n = 10); or 4) 0.25 ng/mL (0.25 ng/mL group, n = 10). Fetuses were infused for 48 h, delivered, and ventilated. The positive control group, negative control group, and mid-point 0.5 ng/mL group animals were tested first. An interim analysis informed the final betamethasone group tested. Positive control group animals had large, statistically significant improvements in respiratory function. Based on an interim analysis, the 1.0 ng/mL group was studied in favor of the 0.25 ng/mL group. Treatment efficacy was progressively lost at plasma betamethasone concentrations lower than 2 ng/mL. We demonstrated that the acute respiratory benefit conveyed by antenatal steroid exposure in the fetal sheep is progressively lost when constant fetal plasma betamethasone concentrations are reduced below a targeted value of 2 ng/mL.NEW & NOTEWORTHY Lung maturation benefits in preterm lambs were progressively lost when fetal plasma betamethasone concentrations fell below 2 ng/mL. The effective floor threshold for a robust, lung-maturing exposure likely lies between 1 and 2 ng betamethasone per milliliter of plasma. Hypothalamic pituitary adrenal axis signaling and immunocyte populations remained materially disrupted at subtherapeutic steroid concentrations. These data demonstrate the potential to improve antenatal steroid therapy using reduced dose regimens informed by glucocorticoid pharmacokinetics and pharmacodynamics.

Insulin-like growth factor-1 replacement therapy after extremely premature birth: An opportunity to optimize lifelong lung health by preserving the natural sequence of lung development.

The past decades have seen markedly improved survival of increasingly immature preterm infants, yet major health complications persist. This is particularly true for bronchopulmonary dysplasia (BPD), the chronic lung disease of prematurity, which has become the most common sequelae of prematurity and a significant predictor of respiratory morbidity throughout childhood as well as adult life, neurodevelopmental disability, cardiovascular disease, and even death. The need for novel approaches to reduce BPD and related complications of prematurity has never been more critical. Thus, despite major advances in the use of antenatal steroids, surfactant therapy, and improvements in respiratory support, there is a persistent need for developing therapeutic strategies that more specifically reflect our growing understanding of BPD in the post-surfactant age, or the "new BPD." In contrast with the severe lung injury leading to marked fibroproliferative disease from the past, the "new BPD" is primarily characterized by an arrest of lung development as related to more extreme prematurity. This distinction and the continued high incidence of BPD and related sequelae suggest the need to identify therapies that target critical mechanisms that support lung growth and maturation in conjunction with treatments to improve respiratory outcomes across the lifespan. As the prevention of BPD and its severity remains a primary goal, we highlight the concept from preclinical and early clinical observations that insulin-like growth factor 1 (IGF-1) can potentially support the natural sequence of lung growth as a replacement therapy after preterm birth. Data supporting this hypothesis are robust and include observations that low IGF-1 levels persist after extremely preterm birth in human infants and strong preclinical data from experimental models of BPD highlight the therapeutic benefit of IGF-1 in reducing disease. Importantly, phase 2a clinical data in extremely premature infants where replacement of IGF-1 with a human recombinant human IGF-1 complexed with its main IGF-1 binding protein 3, significantly reduced the most severe form of BPD, which is strongly associated with multiple morbidities that have lifelong consequences. As physiologic replacement therapy of surfactant heralded the success of reducing acute respiratory distress syndrome in preterm infants, the paradigm has the potential to become the platform for discovering the next generation of therapies like IGF-1, which becomes deficient after extremely premature birth where endogenous production by the infant is not sufficient to maintain the physiologic levels adequate to support normal organ development and maturation.

Preterm lung and brain responses to mechanical ventilation and corticosteroids.

Mechanical ventilation is necessary to maintain oxygenation and ventilation in many preterm infants. Unfortunately, even short periods of mechanical ventilation can cause lung and airway injury, and initiate the lung inflammation that contributes to the development of bronchopulmonary dysplasia (BPD). The mechanical stretch leads to airway cell differentiation and simplification of the alveoli, and releases cytokines that cause systemic response in other organs. Mechanical ventilation also leads to brain injury (IVH, white and gray matter) and neuronal inflammation that can affect the neurodevelopment of preterm infants. In efforts to decrease BPD, corticosteroids have been used for both prevention and treatment of lung inflammation. Corticosteroids have also been demonstrated to cause neuronal injury, so the clinician must balance the negative effects of both mechanical ventilation and steroids on the brain and lungs. Predictive models for BPD can help assess the infants who will benefit most from corticosteroid exposure. This review describes the lung and brain injury from mechanical ventilation in the delivery room and chronic mechanical ventilation in animal models. It provides updates on the current guidelines for use of postnatal corticosteroids (dexamethasone, hydrocortisone, budesonide, budesonide with surfactant) for the prevention and treatment of BPD, and the effects the timing of each steroid regimen has on neurodevelopment.

Preterm ovine respiratory epithelial cell responses to mechanical ventilation, lipopolysaccharide, and interleukin-13.

Mechanical ventilation causes airway injury, respiratory epithelial cell proliferation, and lung inflammation in preterm sheep. Whether preterm epithelial cells respond similarly to adult epithelial cells or are altered by mechanical ventilation is unknown. We test the hypothesis that mechanical ventilation alters the responses of preterm airway epithelium to stimulation in culture. Respiratory epithelial cells from the trachea, left mainstem bronchi (LMSB), and distal bronchioles were harvested from unventilated preterm lambs, ventilated preterm lambs, and adult ewes. Epithelial cells were grown in culture or on air-liquid interface (ALI) and challenged with combinations of either media only, lipopolysaccharide (LPS; 10 ng/mL), bronchoalveolar fluid (BALF), or interleukin-13 (IL-13). Cell lysates were evaluated for mRNA changes in cytokine, cell type markers, Notch pathway, and acute phase markers. Mechanical ventilation altered preterm respiratory epithelium cell types. Preterm respiratory epithelial cells responded to LPS in culture with larger IL-8 induction than adults, and mechanical ventilation further increased cytokines IL-1ß and IL-8 mRNA induction at 2 h. IL-8 protein is detected in cell media after LPS stimulation. The addition of BALF from ventilated preterm animals increased IL-1ß mRNA to LPS (fivefold) in both preterm and adult cells and suppressed IL-8 mRNA (twofold) in adults. Preterm respiratory epithelial cells, when grown on ALI, responded to IL-13 with an increase in goblet cell mRNA. Preterm respiratory epithelial cells responded to LPS and IL-13 with responses similar to adults. Mechanical ventilation or exposure to BALF from mechanically ventilated animals alters the responses to LPS.NEW & NOTEWORTHY Preterm lamb respiratory epithelial cells can be extracted from the trachea and bronchi and frozen, and the preterm cells can respond in culture to stimulation with LPS or IL-13. Brief mechanical ventilation changes the distribution and cell type of preterm respiratory cells toward an adult phenotype, and mechanical ventilation alters the response to LPS in culture. Bronchoalveolar lavage fluid from preterm lambs receiving mechanical ventilation also alters unventilated preterm and adult responses to LPS.

Chorioamnionitis Causes Kidney Inflammation, Podocyte Damage, and Pro-fibrotic Changes in Fetal Lambs.

Background: Perinatal complications, such as prematurity and intrauterine growth restriction, are associated with increased risk of chronic kidney disease. Although often associated with reduced nephron endowment, there is also evidence of increased susceptibility for sclerotic changes and podocyte alterations. Preterm birth is frequently associated with chorioamnionitis, though studies regarding the effect of chorioamnionitis on the kidney are scarce. In this study, we aim to unravel the consequences of premature birth and/or perinatal inflammation on kidney development using an ovine model. Methods: In a preterm sheep model, chorioamnionitis was induced by intra-amniotic injection of lipopolysaccharide (LPS) at either 2, 8, or 15 days prior to delivery. Control animals received intra-amniotic injections of sterile saline. All lambs were surgically delivered at 125 days' gestation (full term is 150 days) and immediately euthanized for necropsy. Kidneys were harvested and processed for staining with myeloperoxidase (MPO), Wilms tumor-1 (WT1) and alpha-smooth muscle actine (aSMA). mRNA expression of tumor necrosis factor alpha (TNFA), Interleukin 10 (IL10), desmin (DES), Platelet derived growth factor beta (PDGFB), Platelet derived growth factor receptor beta (PDGFRB), synaptopodin (SYNPO), and transforming growth factor beta (TGFB) was measured using quantitative PCR. Results: Animals with extended (but not acute) LPS exposure had an inflammatory response in the kidney. MPO staining was significantly increased after 8 and 15 days (p = 0.003 and p = 0.008, respectively). Expression of TNFA (p = 0.016) and IL10 (p = 0.026) transcripts was increased, peaking on day 8 after LPS exposure. Glomerular aSMA and expression of TGFB was increased on day 8, suggesting pro-fibrotic mesangial activation, however, this was not confirmed with PDFGB or PDGFRB. The number of WT1 positive nuclei in the glomerulus, as well as expression of synaptopodin, decreased, indicating podocyte injury. Conclusion: We report that, in an ovine model of prematurity, LPS-induced chorioamnionitis leads to inflammation of the immature kidney. In addition, this process was associated with podocyte injury and there are markers to support pro-fibrotic changes to the glomerular mesangium. These data suggest a potential important role for antenatal inflammation in the development of preterm-associated kidney disease, which is frequent.

One percent of the clinical dose used for antenatal steroid therapy is sufficient to induce lung maturation when administered directly to the preterm ovine fetus.

Antenatal steroids (ANSs) are routinely administered to women judged to be at imminent risk of preterm delivery. Their principal benefit is precocious functional maturation of the preterm fetal lung. Current dosing regimens expose the mother and fetus to high steroid levels that may be unnecessary, increasing the potential risks of disruption to the maternal and fetal hypothalamic-pituitary-adrenal (HPA) axis and glucose regulation, alterations in placental function, and reduced fetal growth. Using a sheep model of pregnancy, we tested the hypothesis that direct fetal administration of an ultra-low dose course of betamethasone phosphate (∼0.33 mg) would be sufficient to elicit functional maturation of the fetal lung. A jugular catheter was installed in singleton ovine fetuses at 122-day gestation under general anesthesia. Animals were randomized to receive either: 1) fetal intravenous betamethasone phosphate to target fetal plasma betamethasone mean levels of 2 ng/mL for 26 h (fetal treatment group; n = 16); 2) fetal intravenous saline for 26 h and two maternal intramuscular injections of 0.25 mg/kg betamethasone phosphate + betamethasone acetate, simulating a standard clinical treatment (maternal treatment group; n = 12); or 3) fetal intravenous saline only for 26 h (negative control group; n = 10). Fetuses were delivered 48 h after surgery, ventilated for 30 min to allow the collection of lung function and physiological data, and euthanized. Quantitative PCR and Western blots were used to assess markers of lung maturation. The average total betamethasone phosphate dose for the fetal treatment group was 1% (0.3 mg) of the maternal treatment group (31-mg betamethasone phosphate + betamethasone acetate). At 30 min of ventilation, arterial [Formula: see text], pH, heart rate, and ventilation efficacy index (VEI) were significantly (P < 0.05) and equivalently improved in both the fetal treatment group and maternal treatment group, relative to the negative control group. Similarly, SP-A, SP-C, and AQ-5 mRNA expression was significantly higher in both the fetal treatment group and maternal treatment group, relative to negative control. Maternal steroid administration was not required to generate preterm fetal lung maturation in sheep. Using a low dose and targeting steroid treatments directly to the fetus has the potential to significantly reduce maternal exposures, while simultaneously reducing the potential risk of adverse outcomes associated with current clinical dosing regimens.

A potent myeloid response is rapidly activated in the lungs of premature Rhesus macaques exposed to intra-uterine inflammation.

Up to 40% of preterm births are associated with histological chorioamnionitis (HCA), which leads to elevated levels of pro-inflammatory mediators and microbial products in the amniotic fluid, which come in contact with fetal lungs. Yet, fetal pulmonary immune responses to such exposure remain poorly characterized. To address this gap, we used our established HCA model, in which pregnant Rhesus macaques receive intraamniotic (IA) saline or LPS. IA LPS induced a potent and rapid myeloid cell response in fetal lungs, dominated by neutrophils and monocytes/macrophages. Infiltrating and resident myeloid cells exhibited transcriptional profiles consistent with exposure to TLR ligands, as well as cytokines, notably IL-1 and TNFα. Although simultaneous, in vivo blockade of IL-1 and TNFα signaling did not prevent the inflammatory cell recruitment, it blunted the lung overall inflammatory state reducing communication between, and activation of, infiltrating immune cells. Our data indicate that the fetal innate immune system can mount a rapid multi-faceted pulmonary immune response to in utero exposure to inflammation. These data provide mechanistic insights into the association between HCA and the postnatal lung morbidities of the premature infant and highlight therapeutic potential of inflammatory blockade in the fetus.

Inflammatory blockade prevents injury to the developing pulmonary gas exchange surface in preterm primates.

Perinatal inflammatory stress is associated with early life morbidity and lifelong consequences for pulmonary health. Chorioamnionitis, an inflammatory condition affecting the placenta and fluid surrounding the developing fetus, affects 25 to 40% of preterm births. Severe chorioamnionitis with preterm birth is associated with significantly increased risk of pulmonary disease and secondary infections in childhood, suggesting that fetal inflammation may markedly alter the development of the lung. Here, we used intra-amniotic lipopolysaccharide (LPS) challenge to induce experimental chorioamnionitis in a prenatal rhesus macaque (Macaca mulatta) model that mirrors structural and temporal aspects of human lung development. Inflammatory injury directly disrupted the developing gas exchange surface of the primate lung, with extensive damage to alveolar structure, particularly the close association and coordinated differentiation of alveolar type 1 pneumocytes and specialized alveolar capillary endothelium. Single-cell RNA sequencing analysis defined a multicellular alveolar signaling niche driving alveologenesis that was extensively disrupted by perinatal inflammation, leading to a loss of gas exchange surface and alveolar simplification, with notable resemblance to chronic lung disease in newborns. Blockade of the inflammatory cytokines interleukin-1ß and tumor necrosis factor-α ameliorated LPS-induced inflammatory lung injury by blunting stromal responses to inflammation and modulating innate immune activation in myeloid cells, restoring structural integrity and key signaling networks in the developing alveolus. These data provide new insight into the pathophysiology of developmental lung injury and suggest that modulating inflammation is a promising therapeutic approach to prevent fetal consequences of chorioamnionitis.

Direct administration of the non-competitive interleukin-1 receptor antagonist rytvela transiently reduced intrauterine inflammation in an extremely preterm sheep model of chorioamnionitis.

BACKGROUND: Intraamniotic inflammation is associated with up to 40% of preterm births, most notably in deliveries occurring prior to 32 weeks' gestation. Despite this, there are few treatment options allowing the prevention of preterm birth and associated fetal injury. Recent studies have shown that the small, non-competitive allosteric interleukin (IL)-1 receptor inhibitor, rytvela, may be of use in resolving inflammation associated with preterm birth (PTB) and fetal injury. We aimed to use an extremely preterm sheep model of chorioamnionitis to investigate the anti-inflammatory efficacy of rytvela in response to established intra-amniotic (IA) lipopolysaccharide (LPS) exposure. We hypothesized that rytvela would reduce LPS-induced IA inflammation in amniotic fluid (AF) and fetal tissues. METHODS: Sheep with a single fetus at 95 days gestation (estimated fetal weight 1.0 kg) had surgery to place fetal jugular and IA catheters. Animals were recovered for 48 hours before being randomized to either: i) IA administration of 2 ml saline 24 hours before 2 ml IA and 2 ml fetal intravenous (IV) administration of saline (Saline Group, n = 7); ii) IA administration of 10 mg LPS in 2 ml saline 24 hours before 2 ml IA and 2 ml fetal IV saline (LPS Group, n = 10); 3) IA administration of 10 mg LPS in 2 ml saline 24 hours before 0.3 mg/fetal kg IA and 1 mg/fetal kg fetal IV rytvela in 2 ml saline, respectively (LPS + rytvela Group, n = 7). Serial AF samples were collected for 120 h. Inflammatory responses were characterized by quantitative polymerase chain reaction (qPCR), histology, fluorescent immunohistochemistry, enzyme-linked inmmunosorbent assay (ELISA), fluorescent western blotting and blood chemistry analysis. RESULTS: LPS-treated animals had endotoxin and AF monocyte chemoattractant protein (MCP)-1 concentrations that were significantly higher at 24 hours (immediately prior to rytvela administration) relative to values from Saline Group animals. Following rytvela administration, the average MCP-1 concentrations in the AF were significantly lower in the LPS + rytvela Group relative to in the LPS Group. In delivery samples, the expression of IL-1ß in fetal skin was significantly lower in the LPS + rytvela Group compared to the LPS Group. CONCLUSION: A single dose of rytvela was associated with partial, modest inhibition in the expression of a panel of cytokines/chemokines in fetal tissues undergoing an active inflammatory response.

Surfactant-Assisted Distal Pulmonary Distribution of Budesonide Revealed by Mass Spectrometry Imaging.

Direct lung administration of budesonide in combination with surfactant reduces the incidence of bronchopulmonary dysplasia. Although the therapy is currently undergoing clinical development, the lung distribution of budesonide throughout the premature neonatal lung has not yet been investigated. Here, we applied mass spectrometry imaging (MSI) to investigate the surfactant-assisted distal lung distribution of budesonide. Unlabeled budesonide was either delivered using saline as a vehicle (n = 5) or in combination with a standard dose of the porcine surfactant Poractant alfa (n = 5). These lambs were ventilated for one minute, and then the lungs were extracted for MSI analysis. Another group of lambs (n = 5) received the combination of budesonide and Poractant alfa, followed by two hours of mechanical ventilation. MSI enabled the label-free detection and visualization of both budesonide and the essential constituent of Poractant alfa, the porcine surfactant protein C (SP-C). 2D ion intensity images revealed a non-uniform distribution of budesonide with saline, which appeared clustered in clumps. In contrast, the combination therapy showed a more homogeneous distribution of budesonide throughout the sample, with more budesonide distributed towards the lung periphery. We found similar distribution patterns for the SP-C and budesonide in consecutive lung tissue sections, indicating that budesonide was transported across the lungs associated with the exogenous surfactant. After two hours of mechanical ventilation, the budesonide intensity signal in the 2D ion intensity maps dropped dramatically, suggesting a rapid lung clearance and highlighting the relevance of achieving a uniform surfactant-assisted lung distribution of budesonide early after delivery to maximize the anti-inflammatory and maturational effects throughout the lung.

Postnatal steroid management in preterm infants with evolving bronchopulmonary dysplasia.

Bronchopulmonary dysplasia (BPD) is a chronic lung disease commonly affecting extremely preterm infants. Although mechanical ventilation and oxygen requirements in premature infants are identified as inciting mechanisms for inflammation and the development of BPD over time, data now support an array of perinatal events that may stimulate the inflammatory cascade prior to delivery. Corticosteroids, such as dexamethasone and hydrocortisone, have proven beneficial for the prevention and management of BPD postnatally due to their anti-inflammatory characteristics. This review aims to examine the pharmacologic properties of several corticosteroids, appraise the existing evidence for postnatal corticosteroid use in preterm infants, and assess steroid management strategies to ameliorate BPD. Finally, we aim to provide guidance based on clinical experience for managing adrenal suppression resulting from prolonged steroid exposure since this is an area less well-studied.

Sequential Exposure to Antenatal Microbial Triggers Attenuates Alveolar Growth and Pulmonary Vascular Development and Impacts Pulmonary Epithelial Stem/Progenitor Cells.

Perinatal inflammatory stress is strongly associated with adverse pulmonary outcomes after preterm birth. Antenatal infections are an essential perinatal stress factor and contribute to preterm delivery, induction of lung inflammation and injury, pre-disposing preterm infants to bronchopulmonary dysplasia. Considering the polymicrobial nature of antenatal infection, which was reported to result in diverse effects and outcomes in preterm lungs, the aim was to examine the consequences of sequential inflammatory stimuli on endogenous epithelial stem/progenitor cells and vascular maturation, which are crucial drivers of lung development. Therefore, a translational ovine model of antenatal infection/inflammation with consecutive exposures to chronic and acute stimuli was used. Ovine fetuses were exposed intra-amniotically to Ureaplasma parvum 42 days (chronic stimulus) and/or to lipopolysaccharide 2 or 7 days (acute stimulus) prior to preterm delivery at 125 days of gestation. Pulmonary inflammation, endogenous epithelial stem cell populations, vascular modulators and morphology were investigated in preterm lungs. Pre-exposure to UP attenuated neutrophil infiltration in 7d LPS-exposed lungs and prevented reduction of SOX-9 expression and increased SP-B expression, which could indicate protective responses induced by re-exposure. Sequential exposures did not markedly impact stem/progenitors of the proximal airways (P63+ basal cells) compared to single exposure to LPS. In contrast, the alveolar size was increased solely in the UP+7d LPS group. In line, the most pronounced reduction of AEC2 and proliferating cells (Ki67+) was detected in these sequentially UP + 7d LPS-exposed lambs. A similar sensitization effect of UP pre-exposure was reflected by the vessel density and expression of vascular markers VEGFR-2 and Ang-1 that were significantly reduced after UP exposure prior to 2d LPS, when compared to UP and LPS exposure alone. Strikingly, while morphological changes of alveoli and vessels were seen after sequential microbial exposure, improved lung function was observed in UP, 7d LPS, and UP+7d LPS-exposed lambs. In conclusion, although sequential exposures did not markedly further impact epithelial stem/progenitor cell populations, re-exposure to an inflammatory stimulus resulted in disturbed alveolarization and abnormal pulmonary vascular development. Whether these negative effects on lung development can be rescued by the potentially protective responses observed, should be examined at later time points.

Surfactant therapy for COVID-19 related ARDS: a retrospective case-control pilot study.

BACKGROUND: COVID-19 causes acute respiratory distress syndrome (ARDS) and depletes the lungs of surfactant, leading to prolonged mechanical ventilation and death. The feasibility and safety of surfactant delivery in COVID-19 ARDS patients have not been established. METHODS: We performed retrospective analyses of data from patients receiving off-label use of exogenous natural surfactant during the COVID-19 pandemic. Seven COVID-19 PCR positive ARDS patients received liquid Curosurf (720 mg) in 150 ml normal saline, divided into five 30 ml aliquots) and delivered via a bronchoscope into second-generation bronchi. Patients were matched with 14 comparable subjects receiving supportive care for ARDS during the same time period. Feasibility and safety were examined as well as the duration of mechanical ventilation and mortality. RESULTS: Patients showed no evidence of acute decompensation following surfactant installation into minor bronchi. Cox regression showed a reduction of 28-days mortality within the surfactant group, though not significant. The surfactant did not increase the duration of ventilation, and health care providers did not convert to COVID-19 positive. CONCLUSIONS: Surfactant delivery through bronchoscopy at a dose of 720 mg in 150 ml normal saline is feasible and safe for COVID-19 ARDS patients and health care providers during the pandemic. Surfactant administration did not cause acute decompensation, may reduce mortality and mechanical ventilation duration in COVID-19 ARDS patients. This study supports the future performance of randomized clinical trials evaluating the efficacy of meticulous sub-bronchial lavage with surfactant as treatment for patients with COVID-19 ARDS.

Budesonide with surfactant decreases systemic responses in mechanically ventilated preterm lambs exposed to fetal intra-amniotic lipopolysaccharide.

BACKGROUND: Chorioamnionitis is associated with increased rates of bronchopulmonary dysplasia (BPD) in ventilated preterm infants. Budesonide when added to surfactant decreased lung and systemic inflammation from mechanical ventilation in preterm lambs and decreased the rates and severity of BPD in preterm infants. We hypothesized that the addition of budesonide to surfactant will decrease the injury from mechanical ventilation in preterm lambs exposed to intra-amniotic (IA) lipopolysaccharide (LPS). METHODS: Lambs at 126 ± 1 day GA received LPS 10 mg IA 48 h prior to injurious mechanical ventilation. After 15 min, lambs received either surfactant mixed with: (1) saline or (2) Budesonide 0.25 mg/kg, then ventilated with normal tidal volumes for 4 h. Injury markers in the lung, liver, and brain were compared. RESULTS: Compared with surfactant alone, the addition of budesonide improved blood pressures, dynamic compliance, and ventilation, while decreasing mRNA for pro-inflammatory cytokines in the lung, liver, and multiple areas of the brain. LPS caused neuronal activation and structural changes in the brain that were not altered by budesonide. Budesonide was not retained within the lung beyond 4 h. CONCLUSIONS: In preterm lambs exposed to IA LPS, the addition of budesonide to surfactant improved physiology and markers of lung and systemic inflammation. IMPACT: The addition of budesonide to surfactant decreases the lung and systemic responses to injurious mechanical ventilation preterm lambs exposed to fetal LPS. Budesonide was present in the plasma by 15 min and the majority of the budesonide is no longer in the lung at 4 h of ventilation. IA LPS and mechanical ventilation caused structural changes in the brain that were not altered by short-term exposure to budesonide. The budesonide dose of 0.25 mg/kg being used clinically seems likely to decrease lung inflammation in preterm infants with chorioamnionitis.

Chorioamnionitis induces changes in ovine pulmonary endogenous epithelial stem/progenitor cells in utero.

BACKGROUND: Chorioamnionitis, an intrauterine infection of the placenta and fetal membranes, is a common risk factor for adverse pulmonary outcomes in premature infants including BPD, which is characterized by an arrest in alveolar development. As endogenous epithelial stem/progenitor cells are crucial for organogenesis and tissue repair, we examined whether intrauterine inflammation negatively affects these essential progenitor pools. METHODS: In an ovine chorioamnionitis model, fetuses were intra-amniotically exposed to LPS, 2d or 7d (acute inflammation) before preterm delivery at 125d of gestation, or to intra-amniotic Ureaplasma parvum for 42d (chronic inflammation). Lung function, pulmonary endogenous epithelial stem/progenitor pools, and downstream functional markers were studied. RESULTS: Lung function was improved in the 7d LPS and 42d Ureaplasma groups. However, intrauterine inflammation caused a loss of P63+ basal cells in proximal airways and reduced SOX-9 expression and TTF-1+ Club cells in distal airways. Attenuated type-2 cell numbers were associated with lower proliferation and reduced type-1 cell marker Aqp5 expression, indicative for impaired progenitor function. Chronic Ureaplasma infection only affected distal airways, whereas acute inflammation affected stem/progenitor populations throughout the lungs. CONCLUSIONS: Acute and chronic prenatal inflammation improve lung function at the expense of stem/progenitor alterations that potentially disrupt normal lung development, thereby predisposing to adverse postnatal outcomes. IMPACT: In this study, prenatal inflammation improved lung function at the expense of stem/progenitor alterations that potentially disrupt normal lung development, thereby predisposing to adverse postnatal outcomes. Importantly, we demonstrate that these essential alterations can already be initiated before birth. So far, stem/progenitor dysfunction has only been shown postnatally. This study indicates that clinical protocols to target the consequences of perinatal inflammatory stress for the immature lungs should be initiated as early as possible and ideally in utero. Within this context, our data suggest that interventions, which promote function or repair of endogenous stem cells in the lungs, hold great promise.