The new bronchopulmonary dysplasia

Patent Ductus Arteriosus, Hydrocortisone, and Outcome among Infants Born Extremely Preterm: Secondary Analysis of the Hydrocortisone Trial

OBJECTIVE

To examine whether hydrocortisone (HC) modified the relationship of patent ductus arteriosus (PDA) to outcomes among infants born extremely preterm and enrolled in the National Institute of Child Health and Human Development Neonatal Research Network (NRN) HC trial.

STUDY DESIGN

This was a posthoc secondary analysis of infants born <30 weeks' gestation and enrolled in the NRN HC Trial. The primary outcome was moderate to severe bronchopulmonary dysplasia (BPD) or death. Secondary outcomes included moderate to severe BPD, death, necrotizing enterocolitis, late-onset sepsis, days of mechanical ventilation, oxygen supplementation, Z-scores for growth, home oxygen, BPD severity, neurodevelopmental impairment, and moderate to severe cerebral palsy. Analyses for interaction between PDA (defined as treatment to achieve PDA closure) and HC were performed for the primary and secondary outcomes.

RESULTS

Of 800 infants enrolled in the NRN HC trial, PDA was treated in 198 HC treated and 197 placebo-treated infants. HC did not modify the relationship of PDA with BPD or death (P = .93). Regardless of HC treatment, PDA was associated with a significant increase in duration of ventilatory support, oxygen supplementation at 36 weeks postmenstrual age (PMA), BPD severity, decreased weight-for-age Z-score at 36 weeks PMA, moderate to severe BPD, or death at 36 weeks PMA and home oxygen support.

CONCLUSIONS

HC after the second postnatal week did not alter the relationship between PDA and BPD or death among infants born extremely preterm. PDA was associated with several adverse outcomes regardless of HC treatment.

Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension: Screening and Management

Screening for pulmonary hypertension (PH) in infants with bronchopulmonary dysplasia (BPD) was recommended by the American Thoracic Society in 2015. However, the definition of BPD has since changed. This review summarizes the current definition of BPD, the recommendations and tools for screening for PH in infants with BPD, and the various treatment options and outcomes in infants with BPD-PH.

Morphological and molecular aspects of lung development

Healthy breathing relies on normal morphological and functional development of the lung. This includes different prenatal and postnatal developmental stages. Depending on species and postnatal behavior as nest escapers or nest squatters, the duration of individual developmental phases and the state of differentiation of the lungs at birth differ. However, the sequence and morphology of the lung developmental stages are similar in all mammals, so knowledge gained from animal models about development-specific genetic control and regulatory mechanisms can be translated in principle to the human lung. Functional lung development comprises the maturation of the surfactant system, which is closely linked to the morphological development of the pulmonary acini. Although a number of reviews are found in the literature, a presentation that integrates the morphological and molecular regulatory mechanisms is missing. Therefore, the aim of this article was to provide an up-to-date comprehensive review of the main morphological steps and regulatory mechanisms of lung development, including clinical aspects related to developmental disorders.

Interleukin-1 Receptor Antagonists Partially Inhibited Histological Injury but Not Tissue Inflammation in a Sheep Model of Pregnancy

Intrauterine inflammation is a significant cause of early preterm birth and fetal injury. There is a lack of effective interventions for intrauterine inflammation. This study aimed to determine whether direct fetal treatment with IL-1 receptor antagonists (IL-1RA), specifically anakinra (competitive IL-1RA) or rytvela (allosteric IL-1RA), could reduce intrauterine inflammation caused by intraamniotic injection of E. coli lipopolysaccharides (LPS) in a sheep model of pregnancy. We hypothesized the fetal intramuscular administration of IL1-RA therapy would comprehensively resolve intrauterine inflammation caused by LPS in the pregnant sheep model. Date-mated Merino ewes carrying single fetuses were randomized into four groups: LPS Group (10 mg intraamniotic LPS injection followed by saline), RYTVELA Group (10 mg LPS injection followed by 5 mg rytvela), ANAKINRA Group (LPS injection followed by 100 mg anakinra), and SALINE Group (saline injection followed by saline). All LPS-exposed fetuses had elevated bilirubin levels, leukopenia, and increased inflammatory mediators IL-1β, IL-8, tumour necrosis factor alpha (TNFα), and monocyte chemoattractant protein 1 (MCP-1) in amniotic fluid and lung tissue. Both anakinra and rytvela treatments reduced immunocyte infiltration in chorioamniotic membranes and lungs, and microglial staining, and increased the oligodendrocyte staining, but did not significantly resolve overall inflammation compared to the SALINE Group. In conclusion, fetal intramuscular administration of anakinra and rytvela did not effectively resolve intrauterine inflammation but showed potential in reducing tissue invasion and brain injury markers. These findings suggest that modest inflammation reduction may protect against brain injury and preterm birth, though no additional benefit was observed compared to intraamniotic IL-1RA treatment.

Electrical impedance tomography in neonates: a review

Appropriate interventions informed by real-time assessment of pulmonary function in mechanically ventilated critically ill neonates can reduce the incidence of bronchopulmonary dysplasia, pneumothorax, intraventricular hemorrhage and other complications of newborn life. The respiratory system in neonates is uniquely different from older children, and its physiological and anatomic attributes increase neonatal vulnerability to respiratory distress and eventual failure. While significant advancements have been made in developing respiratory support for neonates, such support is accompanied by inherent risks to their delicate lungs. Ventilator-associated lung injury poses a critical concern that can be potentially decreased with more precise, non-invasive, non-radiating, bedside methods for assessing neonatal pulmonary function in real time. Electrical impedance tomography (EIT) is one such tool, with immense potential for real-time pulmonary function monitoring in neonates. Still relatively new and in the earliest stages of clinical adoption, EIT use in neonatal critical care has been reported in several studies. This review discusses the basic features of EIT, its distinct advantages over traditional pulmonary function monitoring tools, the scope of its adoption in neonatal clinical practice, challenges associated with clinical adoption, and prospects for future applications. IMPACT: 1. Individualized care assisted by bedside pulmonary function monitoring can positively impact neonatal critical care and outcomes. 2. Electrical impedance tomography (EIT) has the potential to improve neonatal pulmonary function monitoring and treatment outcomes. 3. Electrical impedance tomography can be adopted as a part of routine neonatal respiratory critical care, especially in the population of patients most at risk for bronchopulmonary dysplasia and acute respiratory complications.

Association of hyaluronan and proteoglycan link protein 1 gene with the need of home oxygen therapy in premature Japanese infants with bronchopulmonary dysplasia

BACKGROUND

Bronchopulmonary dysplasia (BPD) has a lasting effect on the respiratory function of infants, imposing chronic health burdens. BPD is influenced by various prenatal, postnatal, and genetic factors. This study explored the connection between BPD and home oxygen therapy (HOT), and then we examined the association between HOT and a specific single-nucleotide polymorphism (SNP) in the hyaluronan and proteoglycan link protein 1 (HAPLN1) gene among premature Japanese infants.

MATERIALS AND METHODS

Prenatal and postnatal data from 212 premature infants were collected and analyzed by four SNPs (rs975563, rs10942332, rs179851, and rs4703570) around HAPLN1 using the TaqMan polymerase chain reaction method. The clinical characteristics and genotype frequencies of HAPLN1 were assessed and compared between HOT and non-HOT groups.

RESULTS

Individuals with AA/AC genotypes in the rs4703570 SNP exhibited significantly higher HOT rates at discharge than those with CC homozygotes (odds ratio, 1.20, 95% confidence interval, 1.07-1.35, p = .038). A logistic regression analysis determined that CC homozygotes in the rs4703570 SNP did not show a statistically significant independent association with HOT at discharge.

CONCLUSIONS

Although our study did not reveal a correlation between HAPLN1 and the onset of BPD, we observed that individuals with CC homozygosity at the rs4703570 SNP exhibit a reduced risk of HOT.

Childhood outcomes following discharge from a referral bronchopulmonary dysplasia program

OBJECTIVES

The primary objective of this study was to profile the childhood health, development, and health-related quality of life (HR QoL) for children with the most severe bronchopulmonary dysplasia (BPD), those discharged from a quaternary referral program.

STUDY DESIGN

We collected cross-sectional data through telephone interviews with 282 families of children ages 18 months to 11 years who had been discharged from a BPD referral program.

RESULTS

Respiratory morbidities were near universal, with 42% of children ever having required a tracheostomy and severity of these morbidities correlated with parent-reported health and QoL. Developmental morbidities were also marked: 97% required an individualized educational plan. While respiratory morbidities and overall health improved over time, developmental morbidities were increasingly prominent, resulting in lower quality of life.

CONCLUSIONS

Among children referred to a quaternary BPD program, respiratory and developmental morbidities are on numerous counts more severe than any reported in the literature.

Neonatal Sequential Organ Failure Assessment Score Predicts Respiratory Outcomes in Preterm Newborns with Late-Onset Sepsis: A Retrospective Study

INTRODUCTION

Neonatal sequential organ failure assessment (nSOFA) score predicts mortality in preterm newborns. The aim of the study was to assess whether nSOFA score could predict respiratory outcomes in preterm infants with late-onset sepsis (LOS).

METHODS

This retrospective, observational, single-center study enrolled infants with gestational age <32 weeks born between January 2016 and June 2023 who experienced an episode of LOS during NICU stay. The primary outcome was death or bronchopulmonary dysplasia (BPD); secondary outcomes were BPD, death or mechanical ventilation (MV) on day 5 after the onset of LOS, and MV on day 5 after the onset of LOS. The nSOFA score was assessed at the onset of LOS and after 6 ± 1, 12 ± 3, and 24 ± 3 h.

RESULTS

Neonatal SOFA score was significantly higher in patients who developed each outcome versus those who did not at all timings. Maximal nSOFA score during the first 24 h after onset of LOS was an independent predictive factor for death or BPD (p = 0.007), BPD (p = 0.009), and death or MV on day 5 (p = 0.009), areas under the curve (AUC) were 0.740 (95% CI: 0.656-0.828), 0.700 (95% CI: 0.602-0.800), and 0.800 (95% CI: 0.710-0.889), respectively. Maximal nSOFA score also predicted moderate to severe BPD (p = 0.019) and death or moderate to severe BPD (p < 0.001). Maximal nSOFA ≥4 was associated with odds ratio (OR) of 7.37 (95% CI: 2.42-22.44) for death or BPD, 4.86 (95% CI: 1.54-15.28) for BPD, and 7.99 (95% CI: 3.47-18.36) for death or MV on day 5. AUC of the predicting model was 0.895 (95% CI: 0.801-0.928) for BPD, 0.897 (95% CI: 0.830-0.939) for death or BPD, 0.904 (95% CI: 0.851-0.956) for MV on day 5, 0.923 (95% CI: 0.892-0.973) for death or MV on day 5.

CONCLUSION

Maximal nSOFA score during the first 24 h after the onset of LOS predicts respiratory outcomes and allows identification of patients who may crucially benefit from lung-protective measures.

Oral ibuprofen versus placebo in closure of patent ductus arteriosus in preterm neonates, a randomized control trial

BACKGROUND

A consensus on treatment of patent ductus arteriosus (PDA) in preterm neonates remains elusive. Conservative management has recently gained popularity due to medical treatment lacking the evidence of benefit in terms of mortality and morbidity.

OBJECTIVE

This study compares the efficacy of the standard dose of oral Ibuprofen versus placebo in the closure of PDA in preterm neonates ≤34 weeks gestation.

METHODS

Eighty enrolled preterm neonates with a hemodynamically significant PDA (hsPDA) were randomized to either receive an early 3-day course oral ibuprofen or placebo (1:1). The open-label option and an extended oral ibuprofen therapy were offered if there were concerns over patient's clinical condition being attributed to PDA and only if showing evidence of systemic and/or pulmonary hyperperfusion.

RESULTS

No significant difference in PDA closure between both groups (62.5% vs 65% in Ibuprofen & placebo group respectively, p = .816). No significant difference was observed between groups in mortality (p = 1), Bronchopulmonary dysplasia (BPD) (p = 1), or necrotizing enterocolitis (NEC) (0.5). Placebo group required a longer duration of inotropic support (median of 10 vs 7.5 days in Ibuprofen group, p = .013) and were prescribed more diuretic therapy (27 vs 18 in Ibuprofen group, p = .043).

CONCLUSION

The standard dose of oral ibuprofen was comparable to placebo in early treatment of hsPDA in preterm neonates less than 34 weeks in terms of effect on ductal closure after one course of treatment, incidence of mortality, and morbidities like NEC, and BPD. Failure of ductal closure itself was associated in both groups with increased mortality, failure to reach full feeds, and more use of vasopressors and inotropes.

Role of sex as a biological variable in neonatal alveolar macrophages

The lung macrophages play a crucial role in health and disease. Sexual dimorphism significantly impacts the phenotype and function of tissue-resident macrophages. The primary mechanisms responsible for sexually dimorphic outcomes in bronchopulmonary dysplasia (BPD) remain unidentified. We tested the hypothesis that biological sex plays a crucial role in the transcriptional state of alveolar macrophages, using neonatal murine hyperoxia-induced lung injury as a relevant model for human BPD. The effects of neonatal hyperoxia exposure (95 % FiO2, PND1-5: saccular stage) on the lung myeloid cells acutely after injury and during normoxic recovery were measured. Alveolar macrophages (AM) from room air- and hyperoxia exposed from male and female neonatal murine lungs were subjected to bulk-RNA Sequencing. AMs are significantly depleted in the hyperoxia-exposed lung acutely after injury, with subsequent recovery in both sexes. The transcriptome of the alveolar macrophages is impacted by neonatal hyperoxia exposure and by sex as a biological variable. Pathways related to DNA damage and interferon-signaling were positively enriched in female AMs. Metabolic pathways related to glucose and carbohydrate metabolism were positively enriched in the male AMs, while oxidative phosphorylation was negatively enriched. These pathways were shared with monocytes and airway macrophages from intubated male and female human premature neonates.

Hydrocortisone in very preterm neonates for BPD prevention: meta-analysis and effect size modifiers

OBJECTIVES

To clarify if systemic hydrocortisone, in protocols allowing to start it before the 15th day of life, prevents bronchopulmonary dysplasia (BPD) or other adverse outcomes in very preterm neonates, and to identify any possible effect size modifiers.

STUDY DESIGN

Systematic review and meta-analysis following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Additional analyses included meta-regressions and review of biological plausibility.

RESULTS

Seven trials were included, they were of general good quality and accounted for a total of 2193 infants. Hydrocortisone treatment did not reduce BPD (risk ratio (RR) 0.84 (95% CI 0.64 to 1.04)), but heterogeneity was evident (I2=51.6%). The effect size for BPD is greatest for 10-12 days duration of treatment (β=0.032 (0.01), p=0.007) and tended to be greater in patients with chorioamnionitis (β=-1.5 (0.841), p=0.07). Hydrocortisone treatment may significantly reduce mortality (RR 0.75 (95% CI 0.59 to 0.91)), there is no heterogeneity (I2=0) and the reduction tended to be greater in males (β=-0.06 (0.03), p=0.07). Hydrocortisone may significantly reduce necrotising enterocolitis (NEC; RR 0.72 (95% CI 0.53 to 0.92)); there is neither heterogeneity (I2=0%) nor any effect size modifiers. Hydrocortisone did not affect other adverse outcomes of prematurity.

CONCLUSIONS

Systemic hydrocortisone may be considered, on a case-by-case evaluation, to reduce mortality and NEC, while it does not affect BPD. There are some potential effect size modifiers for mortality and BPD which should be addressed in future explanatory trials.

PROSPERO REGISTRATION NUMBER

CRD42023400520.

Interdisciplinary clinical bronchopulmonary dysplasia programs: development, evolution, and maturation

Multidisciplinary bronchopulmonary dysplasia (BPD) programs provide improved and consistent medical management, care of the developing infant, family support, and smoother transitions in care resulting in improved survival, pulmonary, and extra-pulmonary outcomes. This review summarizes the benefits of interdisciplinary BPD management, as well as strategies for initial programmatic development, program growth, and maintenance at centers across the United States factoring in institutional, provider, and parent reported goals that were derived from a consensus conference on BPD management.

Mitochondrial DNA mutations in extremely preterm infants with bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a serious chronic lung disease affecting extremely preterm infants. While mitochondrial dysfunction has been investigated in various medical conditions, limited research has explored mitochondrial DNA (mtDNA) gene mutations, specifically in BPD. This study aimed to evaluate mitochondrial mtDNA gene mutations in extremely preterm infants with BPD. In this prospective observational study, we enrolled a cohort of extremely preterm infants diagnosed with BPD. Clinical data were collected to provide comprehensive patient profiles. Peripheral blood mononuclear cells were isolated from whole-blood samples obtained within a defined timeframe. Subsequently, mtDNA extraction and sequencing using next-generation sequencing technology were performed to identify mtDNA gene mutations. Among the cohort of ten extremely preterm infants with BPD, mtDNA sequencing revealed the presence of mutations in seven patients, resulting in a total of twenty-one point mutations. Notably, many of these mutations were identified in loci associated with critical components of the respiratory chain complexes, vital for proper mitochondrial function and cellular energy production. This pilot study provides evidence of mtDNA point mutations in a subset of extremely preterm infants with BPD. These findings suggest a potential association between mitochondrial dysfunction and the pathogenesis of BPD. Further extensive investigations are warranted to unravel the mechanisms underlying mtDNA mutations in BPD.

Rates of bronchopulmonary dysplasia in very low birth weight neonates: a systematic review and meta-analysis

IMPORTANCE

Large-scale estimates of bronchopulmonary dysplasia (BPD) are warranted for adequate prevention and treatment. However, systematic approaches to ascertain rates of BPD are lacking.

OBJECTIVE

To conduct a systematic review and meta-analysis to assess the prevalence of BPD in very low birth weight (≤ 1,500 g) or very low gestational age (< 32 weeks) neonates.

DATA SOURCES

A search of MEDLINE from January 1990 until September 2019 using search terms related to BPD and prevalence was performed.

STUDY SELECTION

Randomized controlled trials and observational studies evaluating rates of BPD in very low birth weight or very low gestational age infants were eligible. Included studies defined BPD as positive pressure ventilation or oxygen requirement at 28 days (BPD28) or at 36 weeks postmenstrual age (BPD36).

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently conducted all stages of the review. Random-effects meta-analysis was used to calculate the pooled prevalence. Subgroup analyses included gestational age group, birth weight group, setting, study period, continent, and gross domestic product. Sensitivity analyses were performed to reduce study heterogeneity.

MAIN OUTCOMES AND MEASURES

Prevalence of BPD defined as BPD28, BPD36, and by subgroups.

RESULTS

A total of 105 articles or databases and 780,936 patients were included in this review. The pooled prevalence was 35% (95% CI, 28-42%) for BPD28 (n = 26 datasets, 132,247 neonates), and 21% (95% CI, 19-24%) for BPD36 (n = 70 studies, 672,769 neonates). In subgroup meta-analyses, birth weight category, gestational age category, and continent were strong drivers of the pooled prevalence of BPD.

CONCLUSIONS AND RELEVANCE

This study provides a global estimation of BPD prevalence in very low birth weight/low gestation neonates.

Prevalence, Severity Patterns and Risk Factors of Bronchopulmonary Dysplasia in Preterm Infants Younger than 32 Weeks of Gestation in a Tertiary Centre in Oman

Objectives

This study aimed to determine the rate and severity patterns of bronchopulmonary dysplasia (BPD) and identify antenatal and postnatal factors associated with BPD in preterm infants <32 weeks of gestational age (GA).

Methods

This retrospective observational study included preterm neonates <32 weeks of gestation admitted into the neonatal intensive care unit between January 2010 and December 2017 at Sultan Qaboos University Hospital, Muscat, Oman. A data set of antenatal and perinatal factors were collected. BPD was defined as the need for oxygen and/or respiratory support at 36 weeks post-menstrual age (PMA). Infants with and without BPD were compared in their antenatal and perinatal factors.

Results

A total of 589 preterm infants <32 weeks were admitted. Among them, 505 (85.7%) survived to 36 weeks' PMA and 90 (17.8%) had BPD. The combined BPD and mortality rate was 28.4%. Grades 1, 2 and 3 BPD constituted 77.8%, 7.8% and 14.4%, respectively. BPD was associated with lower GA, lower birth weight, need for intubation at resuscitation, lower Apgar scores, longer duration of ventilation, surfactant therapy and higher rates of neonatal morbidities. On binary logistic regression analysis, predictors of BPD were longer duration of ventilation, intraventricular haemorrhage (IVH) and necrotising enterocolitis (NEC).

Conclusion

In an Omani centre, 17.8% of preterm infants (<32 weeks GA) developed BPD. Various perinatal and neonatal factors were associated with BPD. However, longer duration of ventilation, IVH grades 1 and 2 and NEC stages II and III were significant predictors. Future multicentre research is necessary to provide the overall prevalence of BPD in Oman to help optimise the resources for BPD prevention and management in preterm infants.

Multiresolution semantic segmentation of biological structures in digital histopathology

Purpose

Semantic segmentation in high-resolution, histopathology whole slide images (WSIs) is an important fundamental task in various pathology applications. Convolutional neural networks (CNN) are the state-of-the-art approach for image segmentation. A patch-based CNN approach is often employed because of the large size of WSIs; however, segmentation performance is sensitive to the field-of-view and resolution of the input patches, and balancing the trade-offs is challenging when there are drastic size variations in the segmented structures. We propose a multiresolution semantic segmentation approach, which is capable of addressing the threefold trade-off between field-of-view, computational efficiency, and spatial resolution in histopathology WSIs.

Approach

We propose a two-stage multiresolution approach for semantic segmentation of histopathology WSIs of mouse lung tissue and human placenta. In the first stage, we use four different CNNs to extract the contextual information from input patches at four different resolutions. In the second stage, we use another CNN to aggregate the extracted information in the first stage and generate the final segmentation masks.

Results

The proposed method reported 95.6%, 92.5%, and 97.1% in our single-class placenta dataset and 97.1%, 87.3%, and 83.3% in our multiclass lung dataset for pixel-wise accuracy, mean Dice similarity coefficient, and mean positive predictive value, respectively.

Conclusions

The proposed multiresolution approach demonstrated high accuracy and consistency in the semantic segmentation of biological structures of different sizes in our single-class placenta and multiclass lung histopathology WSI datasets. Our study can potentially be used in automated analysis of biological structures, facilitating the clinical research in histopathology applications.

Protective Effects of Resveratrol Against Airway Hyperreactivity, Oxidative Stress, and Lung Inflammation in a Rat Pup Model of Bronchopulmonary Dysplasia

Oxygen therapy provides an important treatment for preterm and low-birth-weight neonates, however, it has been shown that prolonged exposure to high levels of oxygen (hyperoxia) is one of the factors contributing to the development of bronchopulmonary dysplasia (BPD) by inducing lung injury and airway hyperreactivity. There is no effective therapy against the adverse effects of hyperoxia. Therefore, this study was undertaken to test the hypothesis that natural phytoalexin resveratrol will overcome hyperoxia-induced airway hyperreactivity, oxidative stress, and lung inflammation. Newborn rats were exposed to hyperoxia (fraction of inspired oxygen - FiO2>95 % O2) or ambient air (AA) for seven days. Resveratrol was supplemented either in vivo (30 mg·kg-1·day-1) by intraperitoneal administration or in vitro to the tracheal preparations in an organ bath (100 mikroM). Contractile and relaxant responses were studied in tracheal smooth muscle (TSM) using the in vitro organ bath system. To explain the involvement of nitric oxide in the mechanisms of the protective effect of resveratrol against hyperoxia, a nitric oxide synthase inhibitor - Nomega-nitro-L-arginine methyl ester (L-NAME), was administered in some sets of experiments. The superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and the tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) levels in the lungs were determined. Resveratrol significantly reduced contraction and restored the impaired relaxation of hyperoxia-exposed TSM (p<0.001). L-NAME reduced the inhibitory effect of resveratrol on TSM contractility, as well as its promotion relaxant effect (p<0.01). Resveratrol preserved the SOD and GPx activities and decreased the expression of TNF-alpha and IL-1beta in hyperoxic animals. The findings of this study demonstrate the protective effect of resveratrol against hyperoxia-induced airway hyperreactivity and lung damage and suggest that resveratrol might serve as a therapy to prevent the adverse effects of neonatal hyperoxia. Keywords: Bronchopulmonary dysplasia, Hyperoxia, Airway hyperreactivity, Resveratrol, Pro-inflammatory cytokines.

Antenatal Endotoxin Induces Dysanapsis in Experimental Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD), the chronic lung disease of prematurity, is characterized by impaired lung development with sustained functional abnormalities due to alterations of airways and the distal lung. Although clinical studies have shown striking associations between antenatal stress and BPD, little is known about the underlying pathogenetic mechanisms. Whether dysanapsis, the concept of discordant growth of the airways and parenchyma, contributes to late respiratory disease as a result of antenatal stress is unknown. We hypothesized that antenatal endotoxin (ETX) impairs juvenile lung function as a result of altered central airway and distal lung structure, suggesting the presence of dysanapsis in this preclinical BPD model. Fetal rats were exposed to intraamniotic ETX (10 μg) or saline solution (control) 2 days before term. We performed extensive structural and functional evaluation of the proximal airways and distal lung in 2-week-old rats. Distal lung structure was quantified by stereology. Conducting airway diameters were measured using micro-computed tomography. Lung function was assessed during invasive ventilation to quantify baseline mechanics, response to methacholine challenge, and spirometry. ETX-exposed pups exhibited distal lung simplification, decreased alveolar surface area, and decreased parenchyma-airway attachments. ETX-exposed pups exhibited decreased tracheal and second- and third-generation airway diameters. ETX increased respiratory system resistance and decreased lung compliance at baseline. Only Newtonian resistance, specific to large airways, exhibited increased methacholine reactivity in ETX-exposed pups compared with controls. ETX-exposed pups had a decreased ratio of FEV in 0.1 second to FVC and a normal FEV in 0.1 second, paralleling the clinical definition of dysanapsis. Antenatal ETX causes abnormalities of the central airways and distal lung growth, suggesting that dysanapsis contributes to abnormal lung function in juvenile rats.

The Diaphragmatic Initiated Ventilatory Assist (DIVA) trial: study protocol for a randomized controlled trial comparing rates of extubation failure in extremely premature infants undergoing extubation to non-invasive neurally adjusted ventilatory assist versus non-synchronized nasal intermittent positive pressure ventilation

BACKGROUND

Invasive mechanical ventilation contributes to bronchopulmonary dysplasia (BPD), the most common complication of prematurity and the leading respiratory cause of childhood morbidity. Non-invasive ventilation (NIV) may limit invasive ventilation exposure and can be either synchronized or non-synchronized (NS). Pooled data suggest synchronized forms may be superior. Non-invasive neurally adjusted ventilatory assist (NIV-NAVA) delivers NIV synchronized to the neural signal for breathing, which is detected with a specialized catheter. The DIVA (Diaphragmatic Initiated Ventilatory Assist) trial aims to determine in infants born 240/7-276/7 weeks' gestation undergoing extubation whether NIV-NAVA compared to non-synchronized nasal intermittent positive pressure ventilation (NS-NIPPV) reduces the incidence of extubation failure within 5 days of extubation.

METHODS

This is a prospective, unblinded, pragmatic, multicenter phase III randomized clinical trial. Inclusion criteria are preterm infants 24-276/7 weeks gestational age who were intubated within the first 7 days of life for at least 12 h and are undergoing extubation in the first 28 postnatal days. All sites will enter an initial run-in phase, where all infants are allocated to NIV-NAVA, and an independent technical committee assesses site performance. Subsequently, all enrolled infants are randomized to NIV-NAVA or NS-NIPPV at extubation. The primary outcome is extubation failure within 5 days of extubation, defined as any of the following: (1) rise in FiO2 at least 20% from pre-extubation for > 2 h, (2) pH ≤ 7.20 or pCO2 ≥ 70 mmHg; (3) > 1 apnea requiring positive pressure ventilation (PPV) or ≥ 6 apneas requiring stimulation within 6 h; (4) emergent intubation for cardiovascular instability or surgery. Our sample size of 478 provides 90% power to detect a 15% absolute reduction in the primary outcome. Enrolled infants will be followed for safety and secondary outcomes through 36 weeks' postmenstrual age, discharge, death, or transfer.

DISCUSSION

The DIVA trial is the first large multicenter trial designed to assess the impact of NIV-NAVA on relevant clinical outcomes for preterm infants. The DIVA trial design incorporates input from clinical NAVA experts and includes innovative features, such as a run-in phase, to ensure consistent technical performance across sites.

TRIAL REGISTRATION

www.

CLINICALTRIALS

gov , trial identifier NCT05446272 , registered July 6, 2022.

Early, low-dose hydrocortisone and near-term brain connectivity in extremely preterm infants

BACKGROUND

Postnatal steroids are used to prevent bronchopulmonary dysplasia in extremely preterm infants but may have adverse effects on brain development. We assessed connectivity metrics of major cerebral and cerebellar white matter pathways at near-term gestational age among infants who did or did not receive a standardized regimen of hydrocortisone during the first 10 days of life.

METHODS

Retrospective cohort study.

PARTICIPANTS

Infants born <28 weeks: Protocol group (n = 33) received at least 50% and not more than 150% of an intended standard dose of 0.5 mg/kg hydrocortisone twice daily for 7 days, then 0.5 mg/kg per day for 3 days; Non-Protocol group (n = 22), did not receive protocol hydrocortisone or completed <50% of the protocol dose. We assessed group differences in near-term diffusion MRI mean fractional anisotropy (FA) and mean diffusivity (MD) across the corticospinal tract, inferior longitudinal fasciculus, corpus callosum and superior cerebellar peduncle.

RESULTS

Groups were comparable in gestational age, post-menstrual age at scan, medical complications, bronchopulmonary dysplasia, and necrotizing enterocolitis. No significant large effect group differences were identified in mean FA or MD in any cerebral or cerebellar tract.

CONCLUSION(S)

Low dose, early, postnatal hydrocortisone was not associated with significant differences in white matter tract microstructure at near-term gestational age.

IMPACT

This study compared brain microstructural connectivity as a primary outcome among extremely preterm infants who did or did not receive early postnatal hydrocortisone. Low dose hydrocortisone in the first 10 days of life was not associated with significant differences in white matter microstructure in major cerebral and cerebellar pathways. Hydrocortisone did not have a significant effect on early brain white matter circuits.

Bridging the Gap: Exploring Bronchopulmonary Dysplasia through the Lens of Biomedical Informatics

Bronchopulmonary dysplasia (BPD), a chronic lung disease predominantly affecting premature infants, poses substantial clinical challenges. This review delves into the promise of biomedical informatics (BMI) in reshaping BPD research and care. We commence by highlighting the escalating prevalence and healthcare impact of BPD, emphasizing the necessity for innovative strategies to comprehend its intricate nature. To this end, we introduce BMI as a potent toolset adept at managing and analyzing extensive, diverse biomedical data. The challenges intrinsic to BPD research are addressed, underscoring the inadequacies of conventional approaches and the compelling need for data-driven solutions. We subsequently explore how BMI can revolutionize BPD research, encompassing genomics and personalized medicine to reveal potential biomarkers and individualized treatment strategies. Predictive analytics emerges as a pivotal facet of BMI, enabling early diagnosis and risk assessment for timely interventions. Moreover, we examine how mobile health technologies facilitate real-time monitoring and enhance patient engagement, ultimately refining BPD management. Ethical and legal considerations surrounding BMI implementation in BPD research are discussed, accentuating issues of privacy, data security, and informed consent. In summation, this review highlights BMI's transformative potential in advancing BPD research, addressing challenges, and opening avenues for personalized medicine and predictive analytics.

Prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) augments neonatal hyperoxic lung injury: Role of cytochrome P450 (CYP)1A1, 1A2, and 1B1

Pregnant women exposed to polycyclic aromatic hydrocarbons (PAHs) are at increased risk for premature delivery. Premature infants often require supplemental oxygen, a known risk factor for bronchopulmonary dysplasia (BPD). Cytochrome P450 (CYP) enzymes have been implicated in hyperoxic lung injury. We hypothesize that prenatal PAH exposure exacerbates oxygen-mediated lung injury in neonatal mice, and that this effect is differentially altered in mice lacking the gene for (Cyp)1a1, 1a2, or 1b1. Timed pregnant wild type (WT) (C57BL/6J) mice were orally administered a PAH mixture of benzo[a]pyrene (BP) and benzo[b]fluoranthene (BbF) or the vehicle corn oil (CO) once daily on gestational days 16-19, and the dose response on postnatal lung injury was examined. In addition, timed pregnant mice with one of four genotypes, WT, Cyp1a1-null, Cyp1a2-null, and Cyp1b1-null, were treated orally with CO or PAH on gestational days 16-19 and exposed to hyperoxia or room air for 14 days. Lung injury was assessed on PND15 by radial alveolar count (RAC) and mean linear intercept (MLI) Gene expression of DNA repair genes in lung and liver were measured. Results showed that neonatal hyperoxic lung injury is augmented by prenatal PAH exposure in a dose-dependent manner. This effect was differentially altered in the Cyp-null mice, with Cyp1a2-null showing the greatest extent of lung injury. We concluded that newborn mice exposed to PAH in utero had more significant lung injury in response to hyperoxia than non-PAH exposed pups, and that CYP1A1 and CYP1A2 are protective against lung injury while CYP1B1 augments lung injury.

Neurodevelopment at 24 months corrected age in extremely preterm infants treated with dexamethasone alternatives during the late postnatal period: a cohort study

The administration of dexamethasone has been associated with suboptimal neurodevelopment. We aimed to compare the development of extremely premature infants treated or not with alternatives to dexamethasone: betamethasone, hydrocortisone hemisuccinate. This retrospective cohort study included infants born before 29 weeks of gestational age, treated or not with late (day ≥ 7) postnatal steroids (betamethasone, hydrocortisone hemisuccinate). The neurodevelopment outcome was evaluated at 24 months corrected age, after adjustment on comorbidities of extreme prematurity. In order to analyse their overall development, data about growth and respiratory outcomes were collected. Among the 192 infants included, 59 (30.7%) received postnatal steroids. Suboptimal neurodevelopment concerned 37/59 (62.7%) postnatal steroid-treated and 43/133 (38.1%; p = 0.002) untreated infants. However, in multivariable analysis, only severe neonatal morbidity (p = 0.007) and male gender (p = 0.027) were associated with suboptimal neurodevelopment outcome at 24 months.  Conclusions: Betamethasone or hydrocortisone hemisuccinate treatment was not an independent risk for suboptimal neurological development, growth and respiratory outcomes assessed at 24 months corrected age in extremely premature infants.  Registration number: The study was registered on the ClinicalTrials.gov register: NCT05055193. What is Known: • Late postnatal steroids are used to treat bronchopulmonary dysplasia • Meta-analyses warned against the neurological risk of dexamethasone use during neonatal period. Early or late hydrocortisone hemisuccinate has been evaluated in multiple studies, none of which have reported an adverse effect on neurodevelopment at least to 2 years. Data about the use of betamethasone are scarce. What is New: • The risk of suboptimal neurodevelopment was higher among extremely premature infants who received postnatal steroids when compared to those who did not. • Betamethasone and hydrocortisone hemisuccinate treatment was not an independent risk factor for suboptimal neurodevelopment at 24 months corrected age.

Cardiopulmonary exercise testing in adolescence following extremely premature birth

BACKGROUND

Although extremely premature birth disrupts lung development, adolescent survivors of extreme prematurity show good clinical and physiologic outcomes. Cardiopulmonary limitations may not be clinically evident at rest. Data regarding exercise limitation in adolescents following preterm birth in the postsurfactant era are limited.

RESEARCH QUESTION

What are the long-term effects of bronchopulmonary dysplasia (BPD) and extreme prematurity (<29 weeks) on ventilatory response during exercise in adolescents in the postsurfactant era?

STUDY DESIGN AND METHODS

We followed a longitudinally recruited cohort of children aged 13-19 years who were born at a gestational age of <29 weeks (study group - SG). We compared the cardiopulmonary exercise testing (CPET) results of those with and without BPD, to their own CPET results from elementary school age (mean 9.09 ± 1.05 years).

RESULTS

Thirty-seven children aged 15.73 ± 1.31 years, mean gestational age 26 weeks ( ± 1.19), completed the study. CPET parameters in adolescence were within the normal range for age, including mean V̇O2 peak of 91% predicted. The BPD and non-BPD subgroups had similar results. In the longitudinal analysis of the SG, improvement was observed in adolescence, compared with elementary school age, in breathing reserve (36.37 ± 18.99 vs. 26.58 ± 17.92, p = 0.044), tidal volume as a fraction of vital capacity achieved at maximal load (0.51 ± 0.13 vs. 0.37 ± 0.08, p < 0.001), and respiratory exchange ratio at maximal load (1.18 ± 0.13 vs. 1.11 ± 0.10, p = 0.021).

INTERPRETATION

In the current cohort, adolescents born extremely premature have essentially normal ventilatory response during exercise, unrelated to BPD diagnosis. CPET results in this population improve over time.

Less Invasive Surfactant Administration (LISA) Versus INSURE Method in Preterm Infants: a Retrospective Study

Background

Respiratory distress syndrome (RDS) is a major cause of morbidity and mortality in preterm infants. Early nasal CPAP and selective administration of surfactant via the endotracheal tube are widely used in the treatment of RDS in preterm infants.

Objective

The aim of this study was to compare the need for intubation and mechanical ventilation after surfactant delivery between LISA-treated and INSURE-treated premature infants with respiratory distress syndrome (RDS).

Methods

Retrospective registry-based cohort study enrolled 36 newborns admitted to the neonatal intensive care unit of the "Santa Maria" Hospital of Terni between 2016 and 2023. As a primary outcome, we followed the need for intubation and mechanical ventilation within 72 hours of life, while the secondary outcomes were major neonatal morbidities and death before discharge.

Results

The LISA group and the INSURE group included 13 and 23 newborns respectively. Demographic features showed no significant differences between the two groups. The need for mechanical ventilation in the first 72 hours of life was similar in both groups (p >0.99). There were no significant differences in morbidities.

Conclusion

LISA and INSURE are equally effective modalities for surfactant administration for the treatment of RDS in preterm infants.

Less Invasive Surfactant Administration: A Viewpoint

The standard of care in treating respiratory distress syndrome in preterm infants is respiratory support with nasal continuous positive airway pressure or a combination of continuous positive airway pressure and exogenous surfactant replacement. Endotracheal intubation, the conventional method for surfactant administration, is an invasive procedure associated with procedural and mechanical ventilation complications. The INSURE (intubation, surfactant administration, and extubation soon after) technique is an accepted method aimed at reducing the short-term complications and long-term morbidities related to mechanical ventilation but does not eliminate risks associated with endotracheal intubation and mechanical ventilation. Alternative methods of surfactant delivery that can overcome the problems associated with the INSURE technique are surfactant through a laryngeal mask, surfactant through a thin intratracheal catheter, and aerosolized surfactant delivered using nebulizers. The three alternative methods of surfactant delivery studied in the last two decades have advantages and limitations. More than a dozen randomized controlled trials have aimed to study the benefits of the three alternative techniques of surfactant delivery compared with INSURE as the control arm, with promising results in terms of reduction in mortality, need for mechanical ventilation, and bronchopulmonary dysplasia. The need to find a less invasive surfactant administration technique is a clinically relevant problem. Before broader adoption in routine clinical practice, the most beneficial technique among the three alternative strategies should be identified. This review aims to summarize the current evidence for using the three alternative techniques of surfactant administration in neonates, compare the three techniques, highlight the knowledge gaps, and suggest future directions. KEY POINTS: · The need to find a less invasive alternative method of surfactant delivery is a clinically relevant problem.. · Clinical trials that have studied alternative surfactant delivery methods have shown promising results but are inconclusive for broader adoption into clinical practice.. · Future studies should explore novel clinical trial methodologies and select clinically significant long term outcomes for comparison..

Prenatal FGFR2 Signaling via PI3K/AKT Specifies the PDGFRA+ Myofibroblast

It is well known that FGFR2 (fibroblast growth factor receptor 2) signaling is critical for proper lung development. Recent studies demonstrate that epithelial FGFR2 signaling during the saccular phase of lung development (sacculation) regulates alveolar type 1 (AT1) and AT2 cell differentiation. During sacculation, PDGFRA (platelet-derived growth factor receptor-α)-positive lung fibroblasts exist as three functional subtypes: contractile myofibroblasts, extracellular matrix-producing matrix fibroblasts, and lipofibroblasts. All three subtypes are required during alveolarization to establish a niche that supports AT2 epithelial cell self-renewal and AT1 epithelial cell differentiation. FGFR2 signaling directs myofibroblast differentiation in PDGFRA+ fibroblasts during alveolar reseptation after pneumonectomy. However, it remains unknown if FGFR2 signaling regulates PDGFRA+ myo-, matrix, or lipofibroblast differentiation during sacculation. In this study, FGFR2 signaling was inhibited by temporal expression of a secreted dominant-negative FGFR2b (dnFGFR2) by AT2 cells from embryonic day (E) 16.5 to E18.5. Fibroblast and epithelial differentiation were analyzed at E18.5 and postnatal days 7 and 21. At all time points, the number of myofibroblasts was reduced and the number of lipo-/matrix fibroblasts was increased. AT2 cells are increased and AT1 cells are reduced postnatally, but not at E18.5. Similarly, in organoids made with PDGFRA+ fibroblasts from dnFGFR2 lungs, increased AT2 cells and reduced AT1 cells were observed. In vitro treatment of primary wild-type E16.5 adherent saccular lung fibroblasts with recombinant dnFGFR2b/c resulted in reduced myofibroblast contraction. Treatment with the PI3K/AKT activator 740 Y-P rescued the lack of myofibroblast differentiation caused by dnFGFR2b/2c. Moreover, treatment with the PI3K/AKT activator 740 Y-P rescued myofibroblast differentiation in E18.5 fibroblasts isolated from dnFGFR2 lungs.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Changes in respiratory mechanics in response to crystalloid infusions in extremely premature infants

Extremely premature infants are at a higher risk of developing respiratory distress syndrome and circulatory impairments in the first few weeks of life. Administration of normal saline boluses to manage hypotension is a common practice in preterm infants. As a crystalloid, a substantial proportion might leak into the interstitium; most consequently the lungs in the preterm cohorts, putatively affecting ventilation. We downloaded and analyzed ventilator mechanics data in infants managed by conventional mechanical ventilation and administered normal saline bolus for clinical reasons. Data were downloaded for 30 min prebolus, 60 min during the bolus followed by 30 min postbolus. Sixteen infants (mean gestational age 25.2 ± 1 wk and birth weight 620 ± 60 g) were administered 10 mL/kg normal saline over 60 min. The most common clinical indication for saline was hypotension. No significant increase was noted in mean blood pressure after the saline bolus. A significant reduction in pulmonary compliance (mL/cmH2O/kg) was noted (0.43 ± 0.07 vs. 0.38 ± 0.07 vs. 0.33 ± 0.07, P = 0.003, ANOVA). This was accompanied by an elevation in the required peak inspiratory pressure to deliver set volume-guarantee (19 ± 2 vs. 22 ± 2 vs. 22 ± 3 mmHg, P < 0.0001, ANOVA), resulting in a higher respiratory severity score. Normal saline infusion therapy was associated with adverse pulmonary mechanics. Relevant pathophysiologic mechanisms might include translocation of fluid across pulmonary capillaries affected by low vascular tone and heightened permeability in extremes of prematurity, back-pressure effects from raised left atrial volume due to immature left-ventricular myocardium; complemented by the effect of cytokine release from positive pressure ventilation.NEW & NOTEWORTHY Administration of saline boluses is common in premature infants although hypovolemia is an uncommon underlying cause of hypotension. This crystalloid can redistribute into pulmonary interstitial space. In the presence of an immature myocardium and diastolic dysfunction, excess fluid can also be "edemagenic." This study on extremely premature infants (25 wk gestation) noted adverse influence on respiratory physiology after saline infusion. Clinicians need to choose judiciously and reconsider routine use of saline boluses in premature infants.

Dose-dependent impact of human milk feeding on tidal breathing flow-volume loop parameters across the first 2 years of life in extremely low-birth-weight infants: a cohort study

The purpose of this study is to test the hypothesis that higher consumption of human milk (HM) in preterm infants with birth weight (BW) <1000 g is associated with improved lung function in a dose-dependent manner over the first 2 years of corrected age (CA). This retrospective study at an academic medical center included infants with BW <1000g. They had lung function assessment by the tidal breathing flow-volume loop (TBFVL) follow-up visits at 0-3-, 3-6-, 6-12-, 12-18-, and 18-24-month CA. One hundred eighty infants were included in the study with a mean (SD) gestational age 26.5 (1.90) weeks and BW 772.4 (147.0) g, 50% were female, and 60% developed BPD. 62.8% of infants received HM during the NICU stay. According to a general linear model (including GA, being small for GA (SGA), sex, human milk percentage, sepsis, and BPD), on average, each week of GA resulted in a higher tPTEF/tE of 1.24 (p = 0.039) and being SGA in a lower tPTEF/tE of 5.75 (p = 0.013) at 0-3-month CA. A higher percentage of human milk out of the total enteral intake was associated with better tPTEF/tE z-scores at 0-3 months (p = 0.004) and 18-24 months of CA (p = 0.041). BPD diagnosis was associated with a relevantly worse tPTEF/tE z-score at 6-12 months of CA (p = 0.003).

CONCLUSION

Preterm infants with higher consumption of HM had significantly less airway obstruction across the first 2 years, suggesting that human milk may contribute in a dose-dependent manner to improve lung function in early childhood in former preterm infants born ELBW.

WHAT IS KNOWN

• Human milk feeding reduces the risk of prematurity-related morbidities, including necrotizing enterocolitis, sepsis, lower respiratory tract infections, and BPD. Both exclusive and partial human milk feeding appear to be associated with a lower risk of BPD in preterm infants.

WHAT IS NEW

• This cohort study of 180 preterm infants with birth weight < 1000 g found that exposure to human milk during hospitalization improves airway obstruction markers tPTEF/tE z-score over the first 2 years of corrected age in a dose-dependent manner.

Glucocorticoid signature of preterm infants developing bronchopulmonary dysplasia

BACKGROUND

Systemic inflammation plays a key role in the development of bronchopulmonary dysplasia (BPD). Cortisol is known to dampen inflammation. However, adrenal function following preterm birth is characterized by insufficient cortisol levels for the degree of inflammation, and a relative abundancy of cortisol precursors. We investigated whether this pattern could contribute to the development of BPD in preterm infants born <30 weeks of gestation.

METHODS

Cortisol, cortisone, 17-OH progesterone (17-OHP) and 11-deoxycortisol were measured in serum obtained at postnatal days 1, 3, 7, 14 and 28, using liquid-chromatography-tandem-mass-spectrometry. The presence of BPD was ascertained at 36 weeks postmenstrual age.

RESULTS

Sixty-five infants were included for analysis, of whom 32 (49%) developed BPD. Preterm infants developing BPD, as compared to those without BPD, had higher levels of 17-OHP, 11-deoxycortisol and cortisone relative to cortisol in their first week of life, but not at birth or beyond day 7.

CONCLUSION

Preterm infants developing BPD had higher levels of cortisol precursors and cortisone relative to cortisol in their first week of life than infants without BPD. These findings suggest that BPD is preceded by an activated hypothalamus-pituitary-adrenal axis that could not meet the high cortisol demands, which may predispose to inflammation and BPD.

IMPACT

Relative adrenal insufficiency is common in the first weeks after preterm birth, resulting in insufficient cortisol production for the degree of inflammation and a relative abundance of cortisol precursors; Whether this pattern contributes to the development of bronchopulmonary dysplasia (BPD) is not fully elucidated, since most studies focused on cortisol levels; Preterm infants developing BPD had higher levels of cortisol precursors and cortisone relative to cortisol in the first week of life, suggestive of a hypothalamus-pituitary-adrenal-axis activation during BPD development which cannot meet the high cortisol demands in tissues; This glucocorticoid pattern is likely to dispose to inflammation and BPD.

Mesenchymal stromal/stem cells and bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a common complication in preterm infants, leading to chronic respiratory disease. There has been an improvement in perinatal care, but many infants still suffer from impaired branching morphogenesis, alveolarization, and pulmonary capillary formation, causing lung function impairments and BPD. There is an increased risk of respiratory infections, pulmonary hypertension, and neurodevelopmental delays in infants with BPD, all of which can lead to long-term morbidity and mortality. Unfortunately, treatment options for Bronchopulmonary dysplasia are limited. A growing body of evidence indicates that mesenchymal stromal/stem cells (MSCs) can treat various lung diseases in regenerative medicine. MSCs are multipotent cells that can differentiate into multiple cell types, including lung cells, and possess immunomodulatory, anti-inflammatory, antioxidative stress, and regenerative properties. MSCs are regulated by mitochondrial function, as well as oxidant stress responses. Maintaining mitochondrial homeostasis will likely be key for MSCs to stimulate proper lung development and regeneration in Bronchopulmonary dysplasia. In recent years, MSCs have demonstrated promising results in treating and preventing bronchopulmonary dysplasia. Studies have shown that MSC therapy can reduce inflammation, mitochondrial impairment, lung injury, and fibrosis. In light of this, MSCs have emerged as a potential therapeutic option for treating Bronchopulmonary dysplasia. The article explores the role of MSCs in lung development and disease, summarizes MSC therapy's effectiveness in treating Bronchopulmonary dysplasia, and delves into the mechanisms behind this treatment.

Loss of growth differentiation factor 15 exacerbates lung injury in neonatal mice

Growth differentiation factor 15 (GDF15) is a divergent member of the transforming growth factor-β (TGF-β) superfamily, and its expression increases under various stress conditions, including inflammation, hyperoxia, and senescence. GDF15 expression is increased in neonatal murine bronchopulmonary dysplasia (BPD) models, and GDF15 loss exacerbates oxidative stress and decreases cellular viability in vitro. Our overall hypothesis is that the loss of GDF15 will exacerbate hyperoxic lung injury in the neonatal lung in vivo. We exposed neonatal Gdf15-/- mice and wild-type (WT) controls on a similar background to room air or hyperoxia (95% [Formula: see text]) for 5 days after birth. The mice were euthanized on postnatal day 21 (PND 21). Gdf15-/- mice had higher mortality and lower body weight than WT mice after exposure to hyperoxia. Hyperoxia exposure adversely impacted alveolarization and lung vascular development, with a greater impact in Gdf15-/- mice. Interestingly, Gdf15-/- mice showed lower macrophage count in the lungs compared with WT mice both under room air and after exposure to hyperoxia. Analysis of the lung transcriptome revealed marked divergence in gene expression and enriched biological pathways in WT and Gdf15-/- mice and differed markedly by biological sex. Notably, pathways related to macrophage activation and myeloid cell homeostasis were negatively enriched in Gdf15-/- mice. Loss of Gdf15 exacerbates mortality, lung injury, and the phenotype of the arrest of alveolarization in the developing lung with loss of female-sex advantage in Gdf15-/- mice.NEW & NOTEWORTHY We show for the first time that loss of Gdf15 exacerbates mortality, lung injury, and the phenotype of the arrest of alveolarization in the developing lung with loss of female-sex advantage in Gdf15-/- mice. We also highlight the distinct pulmonary transcriptomic response in the Gdf15-/- lung including pathways related to macrophage recruitment and activation.

Severity of preterm birth and the risk of pulmonary hypertension in childhood: A population-based cohort study in Sweden

BACKGROUND

Preterm birth (<37 completed gestational weeks) has been linked to pulmonary hypertension (PH), but the relationship to severity of preterm birth has not been studied.

OBJECTIVES

We investigated associations between extremely (<28 weeks), very (28-31 weeks), moderately (32-36 weeks) preterm birth, early-term birth (37-38 weeks) and later PH. Additionally, we explored associations between birthweight for gestational age and PH.

METHODS

This registry-based cohort study followed 3.1 million individuals born in Sweden (1987-2016) from 1 up to a maximum of 30 years of age. The outcome was diagnosis or death from PH in national health registers. Adjusted hazard ratios (HR) were estimated using Cox regression analysis. Unadjusted and confounder-adjusted incidence rate differences were also calculated.

RESULTS

Of 3,142,812 individuals, there were 543 cases of PH (1.2 per 100,000 person-years), 153 of which in individuals without malformations. Compared with individuals born at 39 weeks, adjusted HRs with 95% confidence interval (CI) for PH for extremely, moderately, and very preterm birth were 68.78 (95% CI 49.49, 95.57), 13.86 (95% CI 9.27, 20.72) and 3.42 (95% CI 2.46, 4.74), respectively, and for early-term birth 1.74 (1.31, 2.32). HRs were higher in subjects without malformations. There were 90 additional cases of PH per 100,000 person-years in the extremely preterm group (50 after excluding malformations). Very small for gestational age (below 2 SD from estimated birthweight for gestational age and sex) was also associated with increased risk of PH (adjusted HR 2.02, 95% CI 1.14, 3.57).

CONCLUSIONS

We found an inverse association between gestational age and later PH, but the incidence and absolute risks are low. The severity of preterm birth adds clinically relevant information to the assessment of cardiovascular risks in childhood.

Quercetin supplementation attenuates airway hyperreactivity and restores airway relaxation in rat pups exposed to hyperoxia

Hyperoxia exposure of immature lungs contributes to lung injury and airway hyperreactivity. Up to now, treatments of airway hyperreactivity induced by hyperoxia exposure have been ineffective. The aim of this study was to investigate the effects of quercetin on hyperoxia-induced airway hyperreactivity, impaired relaxation, and lung inflammation. Newborn rats were exposed to hyperoxia (FiO2 > 95%) or ambient air (AA) for seven days. Subgroups were injected with quercetin (10 mg·kg-1·day-1). After exposures, tracheal cylinders were prepared for in vitro wire myography. Contraction to methacholine was measured in the presence or absence of organ bath quercetin and/or Nω-nitro-L-arginine methyl ester (L-NAME). Relaxation responses were evoked in preconstricted tissues using electrical field stimulation (EFS). Lung tumor necrosis factor-alpha (TNF-α) and interleukin-1β (IL-1β) levels were measured by enzyme-linked immunosorbent assay (ELISA). A P < 0.05 was considered statistically significant. Contractile responses of tracheal smooth muscle (TSM) of hyperoxic animals were significantly increased compared with AA animals (P < 0.001). Treatment with quercetin significantly reduced contraction in hyperoxic groups compared with hyperoxic control (P < 0.01), but did not have any effect in AA groups. In hyperoxic animals, relaxation of TSM was significantly reduced compared with AA animals (P < 0.001), while supplementation of quercetin restored the lost relaxation in hyperoxic groups. Incubation of preparations in L-NAME significantly reduced the quercetin effects on both contraction and relaxation (P < 0.01). Treatment of hyperoxic animals with quercetin significantly decreased the expression of TNF-α and IL-1β compared with hyperoxic controls (P < 0.001 and P < 0.01, respectively).The findings of this study demonstrate the protective effect of quercetin on airway hyperreactivity and suggest that quercetin might serve as a novel therapy to prevent and treat neonatal hyperoxia-induced airway hyperreactivity and inflammation.

Effects of WeChat follow-up management on the psychological distress, care burden, and quality of life of parents of infants with bronchopulmonary dysplasia: a retrospective cohort study

Objective

The objective was to explore the impact of WeChat follow-up management on the psychological distress, care burden, and quality of life of parents of infants with bronchopulmonary dysplasia (BPD) receiving in-home care.

Methods

This was a retrospective cohort study. A total of 101 parents of infants with BPD who were followed up from January 2016 to January 2022 were included in this study. According to different follow-up methods, these patients were classified into the WeChat group and the routine group. The Depression, Anxiety, and Stress Scale-21 (DASS-21), Zarit Caregiver Burden Interview (ZBI), and WHOQOL-BREF were used. The data on the psychological distress, care burden, and quality of life of the parents in the two groups were analyzed and compared at discharge and at the 3-month follow-up.

Results

There was no significant difference in the DASS-21 and ZBI scores at discharge between the parents in the two groups. During the 3-month follow-up, the scores of the DASS-21 anxiety and stress subscale and the ZBI of parents in the WeChat group were significantly lower than those of parents in the routine group (P < 0.05); however, there was no significant difference in the depression subscale score between the two groups (P > 0.05). A comparison of the WHOQOL-BREF score between the two groups showed that the total quality of life score in the WeChat group was significantly higher than that in the routine group (P < 0.05). The scores of the psychological and social relationship fields in the WeChat group were significantly higher than those in the routine group (P < 0.05). The incidence of adverse events during follow-up was significantly lower in the WeChat group than in the routine group (P < 0.05).

Conclusion

WeChat follow-up management is helpful to decrease the anxiety and stress, reduce the care burden, and improve the quality of life of parents of infants with BPD receiving in-home care.

Endothelial to mesenchymal transition in neonatal hyperoxic lung injury: role of sex as a biological variable

Bronchopulmonary dysplasia (BPD) is characterized by an arrest in alveolarization, abnormal vascular development, and variable interstitial fibroproliferation in the premature lung. Endothelial to mesenchymal transition (EndoMT) may be a source of pathological fibrosis in many organ systems. Whether EndoMT contributes to the pathogenesis of BPD is not known. We tested the hypothesis that pulmonary endothelial cells will show increased expression of EndoMT markers upon exposure to hyperoxia and that sex as a biological variable will modulate differences in expression. Wild-type (WT) and Cdh5-PAC CreERT2 (endothelial reporter) neonatal male and female mice (C57BL6) were exposed to hyperoxia (0.95 [Formula: see text]) either during the saccular stage of lung development (95% [Formula: see text]; postnatal day 1-5 [PND1-5]) or through the saccular and early alveolar stages of lung development (75% [Formula: see text]; PND1-14). Expression of EndoMT markers was measured in whole lung and endothelial cell mRNA. Sorted lung endothelial cells (from room air- and hyperoxia-exposed lungs) were subjected to bulk RNA-Seq. We show that exposure of the neonatal lung to hyperoxia leads to upregulation of key markers of EndoMT. Furthermore, using lung sc-RNA-Seq data from neonatal lung we were able to show that all endothelial cell subpopulations including the lung capillary endothelial cells show upregulation of EndoMT-related genes. Markers related to EndoMT are upregulated in the neonatal lung upon exposure to hyperoxia and show sex-specific differences. Mechanisms mediating EndoMT in the injured neonatal lung can modulate the response of the neonatal lung to hyperoxic injury and need further investigation.NEW & NOTEWORTHY We show that neonatal hyperoxia exposure increased EndoMT markers in the lung endothelial cells and this biological process exhibits sex-specific differences.

Early nasal intermittent positive pressure ventilation (NIPPV) versus early nasal continuous positive airway pressure (NCPAP) for preterm infants

BACKGROUND

Nasal continuous positive airway pressure (NCPAP) is a strategy to maintain positive airway pressure throughout the respiratory cycle through the application of a bias flow of respiratory gas to an apparatus attached to the nose. Early treatment with NCPAP is associated with decreased risk of mechanical ventilation exposure and might reduce chronic lung disease. Nasal intermittent positive pressure ventilation (NIPPV) is a form of noninvasive ventilation delivered through the same nasal interface during which patients are exposed to short inflations, along with background end-expiratory pressure.

OBJECTIVES

To examine the risks and benefits of early (within the first six hours after birth) NIPPV versus early NCPAP for preterm infants at risk of or with respiratory distress syndrome (RDS). Primary endpoints are respiratory failure and the need for intubated ventilatory support during the first week of life. Secondary endpoints include the incidence of mortality, chronic lung disease (CLD) (oxygen therapy at 36 weeks' postmenstrual age), pneumothorax, duration of respiratory support, duration of oxygen therapy, and intraventricular hemorrhage (IVH).

SEARCH METHODS

Searches were conducted in January 2023 in CENTRAL, MEDLINE, Embase, Web of Science, and Dissertation Abstracts. The reference lists of related systematic reviews and of studies selected for inclusion were also searched.

SELECTION CRITERIA

We considered all randomized and quasi-randomized controlled trials. Eligible studies compared NIPPV versus NCPAP treatment, starting within six hours after birth in preterm infants (< 37 weeks' gestational age (GA)).

DATA COLLECTION AND ANALYSIS

We collected and analyzed data using the recommendations of the Cochrane Neonatal Review Group.

MAIN RESULTS

We included 17 trials, enrolling 1958 infants in this review. NIPPV likely reduces the rate of respiratory failure (risk ratio (RR) 0.65, 95% confidence interval (CI) 0.54 to 0.78; risk difference (RD) -0.08, 95% CI -0.12 to -0.05; 17 RCTs, 1958 infants; moderate-certainty evidence) and needing endotracheal tube ventilation (RR 0.67, 95% CI 0.56 to 0.81; RD -0.07, 95% CI -0.11 to -0.04; 16 RCTs; 1848 infants; moderate-certainty evidence) amongst infants treated with early NIPPV compared with early NCPAP. The meta-analysis demonstrated that NIPPV may reduce the risk of developing CLD compared to CPAP (RR 0.70, 95% CI 0.52 to 0.92; 12 RCTs, 1284 infants; low-certainty evidence) slightly. NIPPV may result in little to no difference in mortality (RR 0.82, 95% CI 0.62 to 1.10; 17 RCTs; 1958 infants; I2 of 0%; low-certainty evidence), the incidence of pneumothorax (RR 0.92, 95% CI 0.60 to 1.41; 16 RCTs; 1674 infants; I2 of 0%; low-certainty evidence), and rates of severe IVH (RR 0.98, 95% CI 0.53 to 1.79; 8 RCTs; 977 infants; I2 of 0%; low-certainty evidence).

AUTHORS' CONCLUSIONS

When applied within six hours after birth, NIPPV likely reduces the risk of respiratory failure and the need for intubation and endotracheal tube ventilation in very preterm infants (GA 28 weeks and above) with respiratory distress syndrome or at risk for RDS. It may also decrease the rate of CLD slightly. However, most trials enrolled infants with a gestational age of approximately 28 to 32 weeks with an overall mean gestational age of around 30 weeks. As such, the results of this review may not apply to extremely preterm infants that are most at risk of needing mechanical ventilation or developing CLD. Additional studies are needed to confirm these results and to assess the safety of NIPPV compared with NCPAP alone in a larger patient population.

Role of Postnatal Corticosteroids in the Treatment or Prevention of Bronchopulmonary Dysplasia

As the frequency of viable low birth weight preterm babies increases, bronchopulmonary dysplasia (BPD), one of the most important morbidities in these babies, also increases. Using postnatal steroids to reduce the development of BPD has not been fully enlightened. Besides all prevention strategies for reducing the development of BPD, it is known that steroid therapy used in the 1st week of life could induce negative neuromotor development according to current data. It may be recommended to administer low-dose dexamethasone between 8 and 49 days in infants dependent on mechanical ventilators in the postnatal period. It is seen that the use of hydrocortisone in the early period does not cause negative neuromotor development, but it cannot prevent the development of BPD as much as dexamethasone. All intensive care units must have their steroid protocol for BPD and use steroids in cases when the BPD development scale score is >60-65% and should have a goal of trying to keep the cumulative dose at the lowest level.

Oxygen and mechanical stretch in the developing lung: risk factors for neonatal and pediatric lung disease

Chronic airway diseases, such as wheezing and asthma, remain significant sources of morbidity and mortality in the pediatric population. This is especially true for preterm infants who are impacted both by immature pulmonary development as well as disproportionate exposure to perinatal insults that may increase the risk of developing airway disease. Chronic pediatric airway disease is characterized by alterations in airway structure (remodeling) and function (increased airway hyperresponsiveness), similar to adult asthma. One of the most common perinatal risk factors for development of airway disease is respiratory support in the form of supplemental oxygen, mechanical ventilation, and/or CPAP. While clinical practice currently seeks to minimize oxygen exposure to decrease the risk of bronchopulmonary dysplasia (BPD), there is mounting evidence that lower levels of oxygen may carry risk for development of chronic airway, rather than alveolar disease. In addition, stretch exposure due to mechanical ventilation or CPAP may also play a role in development of chronic airway disease. Here, we summarize the current knowledge of the impact of perinatal oxygen and mechanical respiratory support on the development of chronic pediatric lung disease, with particular focus on pediatric airway disease. We further highlight mechanisms that could be explored as potential targets for novel therapies in the pediatric population.

TITLE: New therapeutic approaches in pediatric diseases: Mesenchymal stromal cell and mesenchymal stromal cell-derived extracellular vesicles as new drugs

Mesenchymal Stromal Cell (MSC) clinical applications have been widely reported and their therapeutic potential has been documented in several diseases. MSCs can be isolated from several human tissues and easily expanded in vitro, they are able to differentiate in a variety of cell lineages, and they are known to interact with most immunological cells, showing immunosuppressive and tissue repair properties. Their therapeutic efficacy is closely associated with the release of bioactive molecules, namely Extracellular Vesicles (EVs), effective as their parental cells. EVs isolated from MSCs act by fusing with target cell membrane and releasing their content, showing a great potential for the treatment of injured tissues and organs, and for the modulation of the host immune system. EV-based therapies provide, as major advantages, the possibility to cross the epithelium and blood barrier and their activity is not influenced by the surrounding environment. In the present review, we deal with pre-clinical reports and clinical trials to provide data in support of MSC and EV clinical efficacy with particular focus on neonatal and pediatric diseases. Considering pre-clinical and clinical data so far available, it is likely that cell-based and cell-free therapies could become an important therapeutic approach for the treatment of several pediatric diseases.

Lung Transplantation for Bronchopulmonary Dysplasia

BACKGROUND

Patients with bronchopulmonary dysplasia (BPD) have poor respiratory trajectories and are at increased risk of lung function decline with age. Lung transplant (LTx) is a possible treatment option for this growing patient population, but little has been published on LTx in this patient group.

RESEARCH QUESTION

What are the characteristics of patients with BPD who are listed for LTx? How do waitlist and post-LTx outcomes for BPD compare with LTx for other diagnoses?

STUDY DESIGN AND METHODS

The United Network for Organ Sharing (UNOS) registry was queried for patients of all ages listed for or who underwent LTx (2000-2020). Descriptive analysis, waitlist outcomes, and post-LTx survival at 1, 5, and 10 years were assessed comparing patients with BPD vs LTx patients with other diagnoses. Post-LTx survival for patients with BPD born in the pre-surfactant era (pre-SE, before 1990) and those born in the post-surfactant era (post-SE) was compared. Propensity score matching was performed to control for the risk factors and match patients with BPD with other LTx patients on a 1:1 ratio.

RESULTS

BPD was reported in 65 patients, of whom 32 (49.2%) underwent LTx. Patients with BPD at listing were younger than those with other diagnoses (median age, 21 [interquartile range, 5-31] years vs 57 [45-63] years; P < .001), and more were likely to receive mechanical ventilation at listing (23% vs 3.7%; P < .001). Patients with BPD had an FEV1 of 17% compared with 34% predicted in other patients (P = .002). Patients with BPD had an overall similar post-LTx survival compared with patients with other diagnoses (P = .106), even following propensity score matching (P = .41).

INTERPRETATION

LTx for BPD has increased over the last 20 years. Patients with BPD have similar post-LTx outcomes compared with those of other patient populations in the modern era. Thus, LTx could be considered for patients with BPD experiencing progressive respiratory deterioration.

Developmental diversity and unique sensitivity to injury of lung endothelial subtypes during postnatal growth

At birth, the lung is still immature, heightening susceptibility to injury but enhancing regenerative capacity. Angiogenesis drives postnatal lung development. Therefore, we profiled the transcriptional ontogeny and sensitivity to injury of pulmonary endothelial cells (EC) during early postnatal life. Although subtype speciation was evident at birth, immature lung EC exhibited transcriptomes distinct from mature counterparts, which progressed dynamically over time. Gradual, temporal changes in aerocyte capillary EC (CAP2) contrasted with more marked alterations in general capillary EC (CAP1) phenotype, including distinct CAP1 present only in the early alveolar lung expressing Peg3, a paternally imprinted transcription factor. Hyperoxia, an injury that impairs angiogenesis induced both common and unique endothelial gene signatures, dysregulated capillary EC crosstalk, and suppressed CAP1 proliferation while stimulating venous EC proliferation. These data highlight the diversity, transcriptomic evolution, and pleiotropic responses to injury of immature lung EC, possessing broad implications for lung development and injury across the lifespan.

Association Between Enteral Supplementation With High-Dose Docosahexaenoic Acid and Risk of Bronchopulmonary Dysplasia in Preterm Infants: A Systematic Review and Meta-analysis

Importance

High-dose docosahexaenoic acid (DHA), a long-chain polyunsaturated fatty acid, may affect the risk of bronchopulmonary dysplasia (BPD). However, high-level summative evidence supporting such clinical association in very preterm infants is lacking.

Objective

To examine the association between enteral supplementation with high-dose DHA during the neonatal period and the risk of BPD in preterm infants born at less than 29 weeks' gestation.

Data Sources

PubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials, medRxiv, and ClinicalTrials.gov were searched from inception to August 1, 2022, for eligible articles with no language restrictions.

Study Selection

Randomized clinical trials (RCTs) were eligible for inclusion (1) if their interventions involved direct administration of a minimum DHA supplementation of 40 mg/kg/d or breast milk or formula feeding of at least 0.4% of total fatty acids, and (2) if they reported data on either BPD, death, BPD severity, or a combined outcome of BPD and death.

Data Extraction and Synthesis

Two investigators completed independent review of titles and abstracts, full text screening, data extraction, and quality assessment using the Cochrane Risk of Bias 2.0. Risk ratios (RRs) with 95% CIs were pooled using random-effect meta-analyses.

Main Outcomes and Measures

Primary outcome was BPD using trial-specific definitions, which was further stratified for RCTs that used a more stringent BPD definition based on systematic pulse oximetry assessment at 36 weeks' postmenstrual age. Other outcomes were BPD, death, BPD severity, or combined BPD and death.

Results

Among the 2760 studies screened, 4 RCTs were included, which involved 2304 infants (1223 boys [53.1%]; mean [SD] gestational age, 26.5 [1.6] weeks). Enteral supplementation with high-dose DHA was associated with neither BPD (4 studies [n = 2186 infants]; RR, 1.07 [95% CI, 0.86-1.34]; P = .53; I2 = 72%) nor BPD or death (4 studies [n = 2299 infants]; RR, 1.04 [95% CI, 0.91-1.18]; P = .59; I2 = 61%). However, an inverse association with BPD was found in RCTs that used a more stringent BPD definition (2 studies [n = 1686 infants]; RR, 1.20 [95% CI, 1.01-1.42]; P = .04; I2 = 48%). Additionally, DHA was inversely associated with moderate-to-severe BPD (3 studies [n = 1892 infants]; RR, 1.16 [95% CI, 1.04-1.29]; P = .008; I2 = 0%).

Conclusions and Relevance

Results of this study showed that enteral supplementation with high-dose DHA in the neonatal period was not associated overall with BPD, but an inverse association was found in the included RCTs that used a more stringent BPD definition. These findings suggest that high-dose DHA supplementation should not be recommended to prevent BPD in very preterm infants.

Exhaled Volatile Organic Compounds for Early Prediction of Bronchopulmonary Dysplasia in Infants Born Preterm

OBJECTIVE(S)

To investigate the predictive performances of exhaled breath volatile organic compounds (VOCs) for development of bronchopulmonary dysplasia (BPD) in infants born preterm.

METHODS

Exhaled breath was collected from infants born <30 weeks' gestation at days 3 and 7 of life. Ion-fragments detected by gas-Chromatography-mass-spectrometry analysis were used to derive and internally validate a VOC prediction model for moderate or severe BPD at 36 weeks postmenstrual age. We tested the predictive performance of the National Institute of Child Health and Human Development (NICHD) clinical BPD prediction model with and without VOCs.

RESULTS

Breath samples were collected from 117 infants (mean gestation 26.8 [±1.5] weeks). Thirty-three percent of the infants developed moderate or severe BPD. The VOC model showed a c-statistic of 0.89 (95% confidence interval [CI] 0.80-0.97) and 0.92 (95% CI 0.84-0.99)) for the prediction of BPD at days 3 and 7, respectively. Adding the VOCs to the clinical prediction model in non-invasive supported infants resulted in significant improvement in discriminative power on both days (day 3: c-statistic 0.83 versus 0.92, p-value 0.04; day 7: c-statistic 0.82 versus 0.94, p-value 0.03).

CONCLUSIONS

This study showed that VOC profiles in exhaled breath of preterm infants on non-invasive support in the first week of life differ between those developing and not developing BPD. Adding VOCs to a clinical prediction model significantly improved its discriminative performance.

Risk factors and clinical outcomes of extubation failure in very early preterm infants: a single-center cohort study

BACKGROUND

Early extubation success (ES) in preterm infants may reduce various mechanical ventilation-associated complications; however, extubation failure (EF) can cause adverse short- and long-term outcomes. Therefore, the present study aimed to identify differences in risk factors and clinical outcomes between ES and EF in very early preterm infants.

METHODS

This retrospective study was conducted between January 2017 and December 2021. Premature infants born at 32 weeks' gestational age in whom extubation had failed at least once were assigned to the EF group. Successfully extubated patients with a similar gestational age and birth weight as those in the EF group were assigned to the ES group. EF was defined as the need for re-intubation within 120 h of extubation. Various variables were compared between groups.

RESULTS

The EF rate in this study was 18.6% (24/129), and approximately 80% of patients with EF required re-intubation within 90.17 h. In the ES group, there was less use of inotropes within 7 days of life (12 [63.2%] vs. 22 [91.7%], p = 0.022), a lower respiratory severity score (RSS) at 1 and 4 weeks (1.72 vs. 2.5, p = 0.026; 1.73 vs. 2.92, p = 0.010), and a faster time to reach full feeding (18.7 vs. 29.7, p = 0.020). There was a higher severity of bronchopulmonary dysplasia BPD (3 [15.8%] vs. 14 [58.3%], p = 0.018), longer duration of oxygen supply (66.5 vs. 92.9, p = 0.042), and higher corrected age at discharge (39.6 vs. 42.5, p = 0.043) in the EF group. The cutoff value, sensitivity, and specificity of the respiratory severity score (RSS) at 1 week were 1.98, 0.71, and 0.42, respectively, and the cutoff value, sensitivity, and specificity of RSS at 4 weeks were 2.22, 0.67, and 0.47, respectively.

CONCLUSIONS

EF caused adverse short-term outcomes such as a higher BPD severity and longer hospital stay. Therefore, extubation in very early preterm infants should be carefully evaluated. Using inotropes, feeding, and RSS at 1 week of age can help predict extubation success.

Timing and cell specificity of senescence drives postnatal lung development and injury

Senescence causes age-related diseases and stress-related injury. Paradoxically, it is also essential for organismal development. Whether senescence contributes to lung development or injury in early life remains unclear. Here, we show that lung senescence occurred at birth and decreased throughout the saccular stage in mice. Reducing senescent cells at this stage disrupted lung development. In mice (<12 h old) exposed to hyperoxia during the saccular stage followed by air recovery until adulthood, lung senescence increased particularly in type II cells and secondary crest myofibroblasts. This peaked during the alveolar stage and was mediated by the p53/p21 pathway. Decreasing senescent cells during the alveolar stage attenuated hyperoxia-induced alveolar and vascular simplification. Conclusively, early programmed senescence orchestrates postnatal lung development whereas later hyperoxia-induced senescence causes lung injury through different mechanisms. This defines the ontogeny of lung senescence and provides an optimal therapeutic window for mitigating neonatal hyperoxic lung injury by inhibiting senescence.