Bronchopulmonary dysplasia: what are its links to COPD?

Outpatient inhaled corticosteroid use in bronchopulmonary dysplasia

RATIONALE

In the outpatient setting, inhaled corticosteroids (ICS) are frequently given to children with bronchopulmonary dysplasia (BPD) for treatment of respiratory and asthma-associated symptoms. In this study we sought to determine if correlations existed between ICS use and ICS initiation and patient characteristics and outpatient respiratory outcomes.

METHODS

This study included children with the diagnosis of BPD (n = 661) who were seen in outpatient pulmonary clinics at the Children's Hospital of Philadelphia between 2016 and 2021. Chart review was used to determine patient demographics, use and timing of ICS initiation, asthma diagnosis, and acute care usage following initial hospital discharge.

RESULTS

At the first pulmonary visit, 9.2% of children had been prescribed an ICS at NICU discharge, 13.9% had been prescribed an ICS after NICU discharge but before their first pulmonary appointment, and 6.9% were prescribed an ICS at the completion of initial pulmonary visit. Children started on an ICS as outpatients had a higher likelihood of ER visits (adjusted odds ratio: 2.68 ± 0.7), hospitalizations (4.81 ± 1.16), and a diagnosis of asthma (3.58 ± 0.84), compared to children never on an ICS. Of those diagnosed with asthma, children prescribed an ICS in the outpatient setting received the diagnosis at an earlier age. No associations between NICU BPD severity scores and ICS use were found.

CONCLUSIONS

This study identifies an outpatient BPD phenotype associated with ICS use and ICS initiation independent of NICU severity score. Additionally, outpatient ICS initiation correlates with a subsequent diagnosis of asthma and acute care usage in children with BPD.

Comparison of home-based spirometry and oscillometry measurements in school-age children with bronchopulmonary dysplasia

INTRODUCTION

This study compares home-based oscillometry and spirometry for characterizing respiratory system disease in school-aged children with bronchopulmonary dysplasia (BPD) in clinical research. We hypothesized higher rates of successful completion and abnormal cases identified through oscillometry, with correlations between device measurements.

METHODS

Participants 6-12 years old with BPD in the ongoing Air Quality, Environment and Respiratory Outcomes in BPD (AERO-BPD) study performed oscillometry followed by spirometry at two separate home visits. Parameters measured included airway resistance at 5 Hz(R5), resistance from 5 to 19 Hz(R5-19), resonance frequency(Fres), reactance at 5 Hz(X5), area under the curve between Fres and X5(AX), forced expiratory volume in 1 second(FEV1), forced vital capacity(FVC), and FEV1/FVC. Descriptive statistics identified the proportion of successful tests, correlation in measurements, and rate of lung disease for each device.

RESULTS

Among 76 subjects with 120 paired observations, 95% and 71% of participants successfully performed oscillometry and spirometry, respectively, at home visit one. 98% and 77% successfully performed oscillometry and spirometry, respectively, at home visit two. Odds ratios favored oscillometry (range 5.31-10.13, p < 0.01). FEV1 correlated with AX (correlation coefficient r = -0.27, p = 0.03); FEV1/FVC with AX (r = -0.32, p = 0.02); and FEV1/FVC with R5 (r = -0.37, p = 0.01). AX exhibited the highest prevalence of abnormality at 25%; other oscillometry parameters ranged from 5%-22%. Forty-five to sixty-four percent of participants had abnormal spirometry. Oscillometry assessments had significantly lower odds of capturing lung disease (odds ratios 0.07-0.24, p < 0.0001).

CONCLUSIONS

School-aged children with BPD demonstrated higher success rates in field-based oscillometry than spirometry. Spirometry exhibited higher rates of abnormality than oscillometry. Moderate correlation exists between device measurements.

Hydrogen gas inhalation ameliorates LPS-induced BPD by inhibiting inflammation via regulating the TLR4-NFκB-IL6/NLRP3 signaling pathway in the placenta

INTRODUCTION

Hydrogen (H2) is regarded as a novel therapeutic agent against several diseases owing to its inherent biosafety. Bronchopulmonary dysplasia (BPD) has been widely considered among adverse pregnancy outcomes, without effective treatment. Placenta plays a role in defense, synthesis, and immunity, which provides a new perspective for the treatment of BPD. This study aimed to investigate if H2 reduced the placental inflammation to protect the neonatal rat against BPD damage and potential mechanisms.

METHODS

We induced neonatal BPD model by injecting lipopolysaccharide (LPS, 1 µg) into the amniotic fluid at embryonic day 16.5 as LPS group. LPS + H2 group inhaled 42% H2 gas (4 h/day) until the samples were collected. We primarily analyzed the neonatal outcomes and then compared inflammatory levels from the control group (CON), LPS group and LPS + H2 group. HE staining was performed to evaluate inflammatory levels. RNA sequencing revealed dominant differentially expressed genes. Bioinformatics analysis (GO and KEGG) of RNA-seq was applied to mine the signaling pathways involved in protective effect of H2 on the development of LPS-induced BPD. We further used qRT-PCR, Western blot and ELISA methods to verify differential expression of mRNA and proteins. Moreover, we verified the correlation between the upstream signaling pathways and the downstream targets in LPS-induced BPD model.

RESULTS

Upon administration of H2, the inflammatory infiltration degree of the LPS-induced placenta was reduced, and infiltration significantly narrowed. Hydrogen normalized LPS-induced perturbed lung development and reduced the death ratio of the fetus and neonate. RNA-seq results revealed the importance of inflammatory response biological processes and Toll-like receptor signaling pathway in protective effect of hydrogen on BPD. The over-activated upstream signals [Toll-like receptor 4 (TLR4), nuclear factor kappa-B p65 (NF-κB p65), Caspase1 (Casp1) and NLR family pyrin domain containing 3 (NLRP3) inflammasome] in LPS placenta were attenuated by H2 inhalation. The downstream targets, inflammatory cytokines/chemokines [interleukin (IL)-6, IL-18, IL-1β, C-C motif chemokine ligand 2 (CCL2) and C-X-C motif chemokine ligand 1 (CXCL1)], were decreased both in mRNA and protein levels by H2 inhalation in LPS-induced placentas to rescue them from BPD. Correlation analysis displayed a positive association of TLR4-mediated signaling pathway both proinflammatory cytokines and chemokines in placenta.

CONCLUSION

H2 inhalation ameliorates LPS-induced BPD by inhibiting excessive inflammatory cytokines and chemokines via the TLR4-NFκB-IL6/NLRP3 signaling pathway in placenta and may be a potential therapeutic strategy for BPD.

Musculoskeletal crosstalk in chronic obstructive pulmonary disease and comorbidities: Emerging roles and therapeutic potentials

Chronic Obstructive Pulmonary Disease (COPD) is a multifaceted respiratory disorder characterized by progressive airflow limitation and systemic implications. It has become increasingly apparent that COPD exerts its influence far beyond the respiratory system, extending its impact to various organ systems. Among these, the musculoskeletal system emerges as a central player in both the pathogenesis and management of COPD and its associated comorbidities. Muscle dysfunction and osteoporosis are prevalent musculoskeletal disorders in COPD patients, leading to a substantial decline in exercise capacity and overall health. These manifestations are influenced by systemic inflammation, oxidative stress, and hormonal imbalances, all hallmarks of COPD. Recent research has uncovered an intricate interplay between COPD and musculoskeletal comorbidities, suggesting that muscle and bone tissues may cross-communicate through the release of signalling molecules, known as "myokines" and "osteokines". We explored this dynamic relationship, with a particular focus on the role of the immune system in mediating the cross-communication between muscle and bone in COPD. Moreover, we delved into existing and emerging therapeutic strategies for managing musculoskeletal disorders in COPD. It underscores the development of personalized treatment approaches that target both the respiratory and musculoskeletal aspects of COPD, offering the promise of improved well-being and quality of life for individuals grappling with this complex condition. This comprehensive review underscores the significance of recognizing the profound impact of COPD on the musculoskeletal system and its comorbidities. By unravelling the intricate connections between these systems and exploring innovative treatment avenues, we can aspire to enhance the overall care and outcomes for COPD patients, ultimately offering hope for improved health and well-being.

Dynamic Hippo pathway activity underlies mesenchymal differentiation during lung alveolar morphogenesis

Alveologenesis, the final stage in lung development, substantially remodels the distal lung, expanding the alveolar surface area for efficient gas exchange. Secondary crest myofibroblasts (SCMF) exist transiently in the neonatal distal lung and are crucial for alveologenesis. However, the pathways that regulate SCMF function, proliferation and temporal identity remain poorly understood. To address this, we purified SCMFs from reporter mice, performed bulk RNA-seq and found dynamic changes in Hippo-signaling components during alveologenesis. We deleted the Hippo effectors Yap/Taz from Acta2-expressing cells at the onset of alveologenesis, causing a significant arrest in alveolar development. Using single cell RNA-seq, we identified a distinct cluster of cells in mutant lungs with altered expression of marker genes associated with proximal mesenchymal cell types, airway smooth muscle and alveolar duct myofibroblasts. In vitro studies confirmed that Yap/Taz regulates myofibroblast-associated gene signature and contractility. Together, our findings show that Yap/Taz is essential for maintaining functional myofibroblast identity during postnatal alveologenesis.

Long-term outcomes of infants with severe BPD

Preterm birth disrupts the normal sequence of lung development. Additionally, interventions that support gas exchange, including positive pressure ventilation and supplemental oxygen can further exacerbate lung injury, increasing the risk of developing bronchopulmonary dysplasia (BPD) in infants born preterm. Approximately 50,000 preterm infants each year in the United States develop BPD. Heterogeneous lung pathology involving the upper and lower respiratory tract can contribute to the BPD phenotype and can be age-dependent. These phenotypes include alveolar, upper airway, large airways, small airways, and vascular. Each of these phenotypes may improve, resolve, or persist at different ages, throughout childhood. The development of BPD endotypes can be influenced by gestational age and length and type of respiratory support. Although, long-term pulmonary outcomes of infants with severe BPD are variable, the presence of small airway disease is a common phenotype in school age and adolescent children. In this review we examine the more common respiratory endotypes found in infants and children with severe BPD and discuss the long-term prognosis for cardiovascular, neurological, and gastrointestinal morbidities in this patient population.

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

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

Pulmonary phenotypes of bronchopulmonary dysplasia in the preterm infant

Bronchopulmonary dysplasia (BPD) remains the most common complication of premature birth, imposing a significant and potentially life-long burden on patients and their families. Despite advances in our understanding of the mechanisms that contribute to patterns of lung injury and dysfunctional repair, current therapeutic strategies remain non-specific with limited success. Contemporary definitions of BPD continue to rely on clinician prescribed respiratory support requirements at specific time points. While these criteria may be helpful in broadly identifying infants at higher risk of adverse outcomes, they do not offer any precise information regarding the degree to which each compartment of the lung is affected. In this review we will outline the different pulmonary phenotypes of BPD and discuss important features in the pathogenesis, clinical presentation, and management of these frequently overlapping scenarios.

Nutrition-based implications and therapeutics in the development and recovery of bronchopulmonary dysplasia

Premature births account for over 10% of live births worldwide. Bronchopulmonary dysplasia (BPD) represents a severe sequela in neonates born very prematurely and remains the most common chronic neonatal lung disease, often leading to serious adverse consequences in adulthood. Nutrition plays a crucial role in lung development and repair. Ongoing research has primarily focused on the pathogenesis and prevention of BPD in preterm birth. However, infants with established BPD need specialist medical care that persists throughout their hospitalization and continues after discharge. This manuscript aims to highlight the impact of growth and nutrition on BPD and highlight research gaps to provide direction for future studies. Protective practices include ensuring adequate early energy delivery through parenteral nutrition and enteral feedings while carefully monitoring total fluid intake and the use of breast milk over formula. These nutritional strategies remain the same for infants with established BPD with the addition of limiting the use of diuretics and steroids; but if employed, monitoring carefully without compromising total energy delivery. Functional nutrient supplements with a potential protective role against BPD are revisited, despite the limited evidence of their efficacy, including vitamins, trace elements, zinc, lipids, and sphingolipids. Planning post-intensive care and outpatient longitudinal nutrition support is critical in caring for an infant with established BPD.

Neonatal sequential organ failure assessment score within 72 h after delivery reliably predicts bronchopulmonary dysplasia in very preterm infants

Background

The neonatal sequential organ failure assessment (nSOFA) score is an operational definition of organ dysfunction employed to predict sepsis-associated mortality. However, the relationship between the nSOFA score and bronchopulmonary dysplasia (BPD) has not been investigated clearly. This study evaluates whether the nSOFA score within 72 h after delivery could be used to predict the occurrence of BPD in very preterm infants.

Methods

In this retrospective, single-center cohort study, preterm infants born between 2019 and 2021 were investigated, the nSOFA score was calculated from medical records after admission to the neonatal intensive care unit (NICU) within 72 h after delivery, and the peak value was used for calculation. A logistic regression model was used to evaluate the relationship between the nSOFA score and BPD. Propensity score matching and subgroup analysis were performed to verify the reliability of the results.

Results

Of 238 infants meeting the inclusion criteria, 93 infants (39.1%) were diagnosed with BPD. The receiver operating characteristic curve of the nSOFA score in predicting BPD was 0.790 [95% confidence interval (CI): 0.731-0.849]. The logistic regression model showed that an increment of one in the nSOFA score was related to a 2.09-fold increase in the odds of BPD (95% CI: 1.57-2.76) and 6.36-fold increase when the nSOFA score was higher than 1.5 (95% CI: 2.73-14.79).

Conclusions

The nSOFA score within 72 h after delivery is independently related to BPD and can be used to identify high-risk infants and implement early interventions.

Preterm birth and asthma and COPD in adulthood: a nationwide register study from two Nordic countries

BACKGROUND

Preterm birth affects lungs in several ways but few studies have follow-up until adulthood. We investigated the association of the entire spectrum of gestational ages with specialist care episodes for obstructive airway disease (asthma and chronic obstructive pulmonary disease (COPD)) at age 18-50 years.

METHODS

We used nationwide registry data on 706 717 people born 1987-1998 in Finland (4.8% preterm) and 1 669 528 born 1967-1999 in Norway (5.0% preterm). Care episodes of asthma and COPD were obtained from specialised healthcare registers, available in Finland for 2005-2016 and in Norway for 2008-2017. We used logistic regression to estimate odds ratios (ORs) for having a care episode with either disease outcome.

RESULTS

Odds of any obstructive airway disease in adulthood for those born at <28 or 28-31 completed weeks were 2-3-fold of those born full term (39-41 completed weeks), persisting after adjustments. For individuals born at 32-33, 34-36 or 37-38 weeks, the odds were 1.1- to 1.5-fold. Associations were similar in the Finnish and the Norwegian data and among people aged 18-29 and 30-50 years. For COPD at age 30-50 years, the OR was 7.44 (95% CI 3.49-15.85) for those born at <28 weeks, 3.18 (95% CI 2.23-4.54) for those born at 28-31 weeks and 2.32 (95% CI 1.72-3.12) for those born at 32-33 weeks. Bronchopulmonary dysplasia in infancy increased the odds further for those born at <28 and 28-31 weeks.

CONCLUSION

Preterm birth is a risk factor for asthma and COPD in adulthood. The high odds of COPD call for diagnostic vigilance when adults born very preterm present with respiratory symptoms.

Ozone and childhood respiratory health: A primer for US pediatric providers and a call for a more protective standard

Ground level ozone is a potent respiratory toxicant with decades of accumulated data demonstrating respiratory harms to children. Despite the ubiquity of ozone in the United States, impacting both urban and rural communities, the associated harms of exposure to this important air pollutant are often infrequently or inadequately covered during medical training including pulmonary specialization. Thus, many providers caring for children's respiratory health may have limited knowledge of the harms which may result in reduced discussion of ozone pollution during clinical encounters. Further, the current US air quality standard for ozone does not adequately protect children. In this nonsystematic review, we present basic background information for healthcare providers caring for children's respiratory health, review the US process for setting air quality standards, discuss the respiratory harms of ozone for healthy children and those with underlying respiratory disease, highlight the urgent need for a more protective ozone standard to adequately protect children's respiratory health, review impacts of climate change on ozone levels, and provide information for discussion in clinical encounters.

Perinatal origins of bronchopulmonary dysplasia-deciphering normal and impaired lung development cell by cell

Bronchopulmonary dysplasia (BPD) is a multifactorial disease occurring as a consequence of premature birth, as well as antenatal and postnatal injury to the developing lung. BPD morbidity and severity depend on a complex interplay between prenatal and postnatal inflammation, mechanical ventilation, and oxygen therapy as well as associated prematurity-related complications. These initial hits result in ill-explored aberrant immune and reparative response, activation of pro-fibrotic and anti-angiogenic factors, which further perpetuate the injury. Histologically, the disease presents primarily by impaired lung development and an arrest in lung microvascular maturation. Consequently, BPD leads to respiratory complications beyond the neonatal period and may result in premature aging of the lung. While the numerous prenatal and postnatal stimuli contributing to BPD pathogenesis are relatively well known, the specific cell populations driving the injury, as well as underlying mechanisms are still not well understood. Recently, an effort to gain a more detailed insight into the cellular composition of the developing lung and its progenitor populations has unfold. Here, we provide an overview of the current knowledge regarding perinatal origin of BPD and discuss underlying mechanisms, as well as novel approaches to study the perturbed lung development.

RSV infection does not induce EMT

Respiratory syncytial virus (RSV) infection does not cause severe disease in most of us despite suffering from multiple RSV infections in our lives. However, infants, young children, older adults, and immunocompromised patients are unfortunately vulnerable to RSV-associated severe diseases. A recent study suggested that RSV infection causes cell expansion, resulting in bronchial wall thickening in vitro. Whether the virus-induced changes in the lung airway resemble epithelial-mesenchymal transition (EMT) is still unknown. Here, we report that RSV does not induce EMT in three different in vitro lung models: the epithelial A549 cell line, primary normal human bronchial epithelial cells, and pseudostratified airway epithelium. We found that RSV increases the cell surface area and perimeter in the infected airway epithelium, which is distinct from the effects of a potent EMT inducer, TGF-β1-driven cell elongation-indicative of cell motility. A genome-wide transcriptome analysis revealed that both RSV and TGF-β1 have distinct modulation patterns of the transcriptome, which suggests that RSV-induced changes are distinct from EMT.

Vascular and pulmonary effects of ibuprofen on neonatal lung development

BACKGROUND

Ibuprofen is a nonsteroidal anti-inflammatory drug that is commonly used to stimulate closure of a patent ductus arteriosus (PDA) in very premature infants and may lead to aberrant neonatal lung development and bronchopulmonary dysplasia (BPD).

METHODS

We investigated the effect of ibuprofen on angiogenesis in human umbilical cord vein endothelial cells (HUVECs) and the therapeutic potential of daily treatment with 50 mg/kg of ibuprofen injected subcutaneously in neonatal Wistar rat pups with severe hyperoxia-induced experimental BPD. Parameters investigated included growth, survival, lung histopathology and mRNA expression.

RESULTS

Ibuprofen inhibited angiogenesis in HUVECs, as shown by reduced tube formation, migration and cell proliferation via inhibition of the cell cycle S-phase and promotion of apoptosis. Treatment of newborn rat pups with ibuprofen reduced pulmonary vessel density in the developing lung, but also attenuated experimental BPD by reducing lung inflammation, alveolar enlargement, alveolar septum thickness and small arteriolar wall thickening.

CONCLUSIONS

In conclusion, ibuprofen has dual effects on lung development: adverse effects on angiogenesis and beneficial effects on alveolarization and inflammation. Therefore, extrapolation of the beneficial effects of ibuprofen to premature infants with BPD should be done with extreme caution.

Lung structure and function on MRI in preterm born school children with and without BPD: A feasibility study

BACKGROUND AND OBJECTIVE

The most common respiratory complication of prematurity is bronchopulmonary dysplasia (BPD), leading to structural lung changes and impaired respiratory outcomes. However, also preterm children without BPD may show similar adverse respiratory outcomes. There is a need for a safe imaging modality for preterm children with and without BPD for disease severity assessment and risk stratification. Our objective was to develop a magnetic resonance imaging (MRI) protocol in preterm children with and without BPD at school age.

METHODS

Nine healthy volunteers (median age 11.6 [range: 8.8-12.8] years), 11 preterm children with BPD (11.0 [7.2-15.6] years), and 9 without BPD (11.1 [10.7-12.6] years) underwent MRI. Images were scored on hypo- and hyperintense abnormalities, bronchopathy, and architectural distortion. MRI data were correlated to spirometry. Ventilation and perfusion defects were analyzed using Fourier Decomposition (FD) MRI.

RESULTS

On MRI, children with BPD had higher %diseased lung (9.1 (interquartile range [IQR] 5.9-11.6)%) compared to preterm children without BPD (3.4 (IQR 2.5-5.4)%, p < 0.001) and healthy volunteers (0.4 (IQR 0.1-0.8)%, p < 0.001). %Diseased lung correlated negatively with %predicted FEV₁ (r = -0.40, p = 0.04), FEV₁ /FVC (r = -0.49, p = 0.009) and FEF₇₅ (r = -0.63, p < 0.001). Ventilation and perfusion defects on FD sequence corresponded to hypointense regions on expiratory MRI.

CONCLUSION

Chest MRI can identify structural and functional lung damage at school age in preterm children with and without BPD, showing a good correlation with spirometry. We propose MRI as a sensitive and safe imaging method (without ionizing radiation, contrast agents, or the use of anesthesia) for the long-term follow-up of preterm children.

Area deprivation and respiratory morbidities in children with bronchopulmonary dysplasia

INTRODUCTION

Infants and children diagnosed with bronchopulmonary dysplasia (BPD) have a higher likelihood of recurrent hospitalizations and asthma-like symptoms. Socio-environmental factors that influence the frequency and severity of pulmonary symptoms in these children during the preschool age are poorly understood. In this study, we used the Area Deprivation Index (ADI) to evaluate the relationship between the socio-environmental exposures in children with BPD and respiratory outcomes during the first few years of life.

METHODS

A registry of subjects recruited from outpatient BPD clinics at Johns Hopkins University (n = 909) and the Children's Hospital of Philadelphia (n = 125) between January 2008 and October 2021 was used. Subjects were separated into tertiles by ADI scores aggregated to ZIP codes. Caregiver questionnaires were used to assess the frequency of respiratory morbidities and acute care usage for respiratory symptoms.

RESULTS

The mean gestational age of subjects was 26.8 ± 2.6 weeks with a mean birthweight of 909 ± 404 g. The highest tertile (most deprived) of ADI was significantly associated with emergency department visits (aOR 1.72; p = 0.009), hospital readmissions (aOR 1.66; p = 0.030), and activity limitations (aOR 1.55; p = 0.048) compared to the lowest tertile. No association was seen with steroid, antibiotic or rescue medication use, trouble breathing, or nighttime symptoms.

CONCLUSION

In this study, children with BPD who lived in areas of higher deprivation were more likely to be rehospitalized and have ED visits for respiratory reasons. Identifying socio-environmental factors that contribute to adverse pulmonary outcomes in children with BPD may provide opportunities for earlier interventions to improve long-term pulmonary outcomes.

Association between bronchopulmonary dysplasia and early respiratory morbidity in children with respiratory distress syndrome: a case-control study using nationwide data

Bronchopulmonary dysplasia (BPD) can cause respiratory morbidity beyond the neonatal period. We aimed to analyze the association of BPD on childhood lower respiratory illness (LRI) and asthma among patients diagnosed with respiratory distress syndrome (RDS). This case–control study analyzed data between 2002 and 2015 from a nationwide database. We included 55,066 children with RDS. Two-year LRI and asthma at ages 3 and 5 were assessed. Readmission for LRIs within 2 years of birth occurred in 53.9% and 37.9% of the BPD (n = 9470) and non-BPD (n = 45,596) cases, respectively. In the BPD group, the median number of hospitalizations, mechanical ventilation and oxygen use rates were significantly higher, while the hospitalization duration was significantly longer (P < 0.001 for all). The relative risk of BPD was 1.42 (1.39–1.45) on total readmission and 6.53 (5.96–7.15) on intensive care unit readmission. Asthma prevalence was significantly higher in BPD group (57.6% vs. 48.9% at age 3 and 44.3% vs. 38.2% at age 5, P < 0.001). In children with RDS, BPD could affect repetitive and worse LRI as an independent risk factor for respiratory morbidity during the first 2 years of life. BPD may also be a crucial risk factor for asthma in preschoolers.

Lifelong Lung Sequelae of Prematurity

The clinical, functional, and structural pattern of chronic lung disease of prematurity has changed enormously in last years, mirroring a better perinatal management and an increasing lung immaturity with the survival of increasingly premature infants. Respiratory symptoms and lung function impairment related to prematurity seem to improve over time, but premature birth increases the likelihood of lung function impairment in late childhood, predisposing to chronic obstructive pulmonary disease (COPD). It is mandatory to identify those individuals born premature who are at risk for developing long-term lung disease through a better awareness of physicians, the use of standardized CT imaging scores, and a more comprehensive periodic lung function evaluation. The aim of this narrative review was to provide a systematic approach to lifelong respiratory symptoms, lung function impairment, and lung structural anomalies in order to better understand the specific role of prematurity on lung health.

Endotypes of Prematurity and Phenotypes of Bronchopulmonary Dysplasia: Toward Personalized Neonatology

Bronchopulmonary dysplasia (BPD), the chronic lung disease of prematurity, is increasingly recognized as the consequence of a pathological reparative response of the developing lung to both antenatal and postnatal injury. According to this view, the pathogenesis of BPD is multifactorial and heterogeneous with different patterns of antenatal stress (endotypes) that combine with varying postnatal insults and might distinctively damage the development of airways, lung parenchyma, interstitium, lymphatic system, and pulmonary vasculature. This results in different clinical phenotypes of BPD. There is no clear consensus on which are the endotypes of prematurity but the combination of clinical information with placental and bacteriological data enables the identification of two main pathways leading to birth before 32 weeks of gestation: (1) infection/inflammation and (2) dysfunctional placentation. Regarding BPD phenotypes, the following have been proposed: parenchymal, peripheral airway, central airway, interstitial, congestive, vascular, and mixed phenotype. In line with the approach of personalized medicine, endotyping prematurity and phenotyping BPD will facilitate the design of more targeted therapeutic and prognostic approaches.

Mesenchymal Stromal Cell-Derived Extracellular Vesicles for Neonatal Lung Disease: Tiny Particles, Major Promise, Rigorous Requirements for Clinical Translation

Extreme preterm birth disrupts late lung development and puts newborns at risk of developing chronic lung disease, known as bronchopulmonary dysplasia (BPD). BPD can be associated with life-long complications, and currently no effective treatment is available. Cell therapies are entering the clinics to curb complications of extreme preterm birth with several clinical trials testing the feasibility, safety and efficacy of mesenchymal stromal cells (MSCs). The therapeutic effect of MSCs is contained in their secretome, and nanosized membranous structures released by the MSCs, known as extracellular vesicles (EVs), have been shown to be the therapeutic vectors. Driven by this discovery, the efficacy of EV-based therapy is currently being explored in models of BPD. EVs derived from MSCs, contain a rich cargo of anti-inflammatory and pro-angiogenic molecules, making them suitable candidates to treat multifactorial diseases such as BPD. Here, we review the state-of-the-art of preclinical studies involving MSC-derived EVs in models of BPD and highlight technical and regulatory challenges that need to be addressed before clinical translation. In addition, we aim at increasing awareness regarding the importance of rigorous reporting of experimental details of EV experiments and to increase the outreach of the current established guidelines amongst researchers in the BPD field.

Nutrition and growth in infants with established bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) remains the most common late morbidity of preterm birth. Ongoing clinical care and research have largely focused on the pathogenesis and prevention of BPD in preterm infants. However, preterm infants who develop BPD have significant medical needs that persist throughout their neonatal intensive care unit course and continue post-discharge, including those associated with growth and nutrition. The objective of this manuscript was to provide a review on nutrition and growth in infants with established BPD after discharge from the hospital and to identify the knowledge and research gaps to provide direction for future studies.

Bronchopulmonary dysplasia-A historical perspective

Bronchopulmonary dysplasia (BPD) was first described by Northway et al in 1967. This article describes the evolution of our understanding of the pathophysiology of BPD and the approaches to treatments of this illness developed over the past fifty years. These interventions had their roots in the understanding of the principles of the surface tension present at air-liquid interfaces, which were developed over 150 years before BPD's initial description. Improving outcomes in neonatal care have led to greater survival of preterm and very preterm infants, and to an evolution of the pathogenesis and pathology of BPD, from an illness caused primarily by barotrauma and oxygen toxicity to one of interruption of lung development. While the incidence of BPD has remained about the same in recent decades, this is because survival of infants born at lower gestational ages is increasing. Understanding of molecular, genetic and physiologic mechanisms has led to newer treatments that have mitigated some of the harmful effects of prolonged mechanical ventilation. Recognition of BPD as a chronic multi-system disease has resulted in further improvements in care after discharge from neonatal intensive care. Since many of the origins of chronic obstructive lung disease in adults are based in childhood respiratory illnesses, improving outcomes of BPD in infancy and childhood will undoubtedly lead to improved respiratory outcomes in the adults that these children will become.

Development of lung diffusion to adulthood following extremely preterm birth

Background

Gas exchange in extremely preterm (EP) infants must take place in fetal lungs. Childhood lung diffusing capacity of the lung for carbon monoxide (D_LCO) is reduced; however, longitudinal development has not been investigated. We describe the growth of D_LCO and its subcomponents to adulthood in EP compared with term-born subjects.

Methods

Two area-based cohorts born at gestational age ≤28 weeks or birthweight ≤1000 g in 1982–1985 (n=48) and 1991–1992 (n=35) were examined twice, at ages 18 and 25 years and 10 and 18 years, respectively, and compared with matched term-born controls. Single-breath D_LCO was measured at two oxygen pressures, with subcomponents (membrane diffusion (D_M) and pulmonary capillary blood volume (V_C)) calculated using the Roughton–Forster equation.

Results

Age-, sex- and height-standardised transfer coefficients for carbon monoxide (K_CO) and D_LCO were reduced in EP compared with term-born subjects, and remained so during puberty and early adulthood (p-values for all time-points and both cohorts ≤0.04), whereas alveolar volume (V_A) was similar. Development occurred in parallel to term-born controls, with no signs of pubertal catch-up growth nor decline at age 25 years (p-values for lack of parallelism within cohorts 0.99, 0.65, 0.71, 0.94 and 0.44 for z-D_LCO, z-V_A, z-K_CO, D_M and V_C, respectively). Split by membrane and blood volume components, findings were less clear; however, membrane diffusion seemed most affected.

Conclusions

Pulmonary diffusing capacity was reduced in EP compared with term-born subjects, and development from childhood to adulthood tracked in parallel to term-born subjects, with no signs of catch-up growth nor decline at age 25 years.

Pulmonary diffusing capacity following extremely preterm (EP) birth was reduced compared with term-born subjects. From mid-childhood to adulthood, development tracked in parallel in the EP and term-born groups, with preterms following lower trajectories.https://bit.ly/3ARPD7D

Influences of environmental exposures on preterm lung disease

Introduction: Environmental factors play a critical role in the progression or resolution of chronic respiratory diseases. However, studies are limited on the impact of environmental risk factors on individuals born prematurely with lung disease after they leave the neonatal intensive care unit and are discharged into the home environment.Areas covered: In this review, we cover current knowledge of environmental exposures that impact outcomes of preterm respiratory disease, including air pollution, infections, and disparities. The limited data do suggest that certain exposures should be avoided and there are potential preventative strategies for other exposures. There is a need for additional research outside the neonatal intensive care unit that focuses on individual and community-level factors that affect long-term outcomes.Expert opinion: Preterm respiratory disease can impose a significant burden on infants, children, and young adults born prematurely, but may improve for many individuals over time. In this review, we outline the exposures that may potentially hasten, delay, or prevent resolution of lung injury in preterm children.

Neutrophilic inflammation during lung development disrupts elastin assembly and predisposes adult mice to COPD

Emerging evidence indicates that early life events can increase the risk for developing chronic obstructive pulmonary disease (COPD). Using an inducible transgenic mouse model for NF-κB activation in the airway epithelium, we found that a brief period of inflammation during the saccular stage (P3-P5) but not alveolar stage (P10-P12) of lung development disrupted elastic fiber assembly, resulting in permanent reduction in lung function and development of a COPD-like lung phenotype that progressed through 24 months of age. Neutrophil depletion prevented disruption of elastic fiber assembly and restored normal lung development. Mechanistic studies uncovered a role for neutrophil elastase (NE) in downregulating expression of critical elastic fiber assembly components, particularly fibulin-5 and elastin. Further, purified human NE and NE-containing exosomes from tracheal aspirates of premature infants with lung inflammation downregulated elastin and fibulin-5 expression by saccular-stage mouse lung fibroblasts. Together, our studies define a critical developmental window for assembling the elastin scaffold in the distal lung, which is required to support lung structure and function throughout the lifespan. Although neutrophils play a well-recognized role in COPD development in adults, neutrophilic inflammation may also contribute to early-life predisposition to COPD.

Persistent airflow obstruction in inner-city children with asthma

Background: Airway remodeling has been shown to be persistent in patients with asthma despite treatment with controller medications. Patients with early airflow obstruction may continue to experience poor lung function despite treatment. Objectives: To determine whether early airflow obstruction in inner-city children with asthma persists despite guideline-based asthma care. Methods: In a retrospective study that used a cohort of inner-city children with asthma treated by using an asthma-specific disease management system, the patients were stratified into "low" or "high" lung function groups at the time of the initial visit (high, forced expiratory volume in the first second of expiration [FEV₁] % predicted and FEV₁/forced vital capacity [FVC] ≥ 80%; and low, FEV₁% predicted and FEV₁/FVC < 80%). These patients then received National Heart, Lung, and Blood Institute guideline-based asthma treatment at regular follow-up intervals with spirometry performed at these visits as part of regular care. FEV₁% predicted and FEV₁/FVC were followed up for up to 10 years for both the high and low cohorts. Results: Over 10 years, the patients initially in the "high" group maintained FEV₁% predicted and FEV₁/FVC at values similar to the initial visit (94 to 96% and 87 to 89%, respectively), whereas those in the low group had only slight increases of FEV₁% predicted and FEV₁/FVC over the same time (77 to 82% and 78 to 82%, respectively). Low FEV₁% predicted and FEV₁/FVC at the time of the first visit was significantly associated with an increased risk of low values of these lung functions over the next 3-5 years despite treatment. African American ethnicity and male gender were also associated with lower lung function over time. Conclusion: Early airflow obstruction in inner city children asthma is associated with poor lung function in later life despite guideline-based asthma care. Current asthma therapy may not affect pathways and leads to airway remodeling in children with asthma.

Respiratory outcomes of "new" bronchopulmonary dysplasia in adolescents: A multicenter study

OBJECTIVE

Long-term respiratory consequences of bronchopulmonary dysplasia (BPD) in preterm infants born in the post-surfactant era ("new" BPD) remain partially unknown. The present study aimed to evaluate the respiratory outcomes of "new" BPD in adolescents who were born preterm.

METHODS

This multicenter, cross-sectional study included 286 adolescents born between 2003 and 2005 (mean age: 14.2 years); among them, 184 and 102 were born extremely preterm (EP; <28 weeks' gestation) and moderate-late preterm (32 to <37 weeks' gestation), respectively. Among EP adolescents, 92 had BPD, and 92 did not. All participants underwent lung function tests, skin prick testing, and questionnaires on asthma symptoms and quality of life.

RESULTS

EP adolescents with BPD had significantly lower forced expiratory volume in 1 s (FEV₁ ), forced vital capacity (FVC), FEV₁ /FVC ratio, and forced expiratory flow between 25% and 75% of FVC than other included adolescents. FEV₁ /FVC ratios were below the lower limit of normal (z-score <-1.645) in 30.4% of EP adolescents with BPD, 13.0% of EP adolescents without BPD, and 11.8% of adolescents who were born moderate-late preterm. Bronchodilator response and air-trapping were significantly higher in BPD adolescents than in other adolescents. Diffusion capacity was significantly lower in EP adolescents than in moderate-late preterm adolescents. Asthma symptoms and quality-of-life scores were similar among groups.

CONCLUSION

EP adolescents with "new" BPD had poorer pulmonary function than EP adolescents without BPD or moderate-late preterm adolescents. Further studies are needed to determine whether "new" BPD is associated with early-onset chronic obstructive pulmonary disease in adulthood.

Loss of circadian protection against influenza infection in adult mice exposed to hyperoxia as neonates

Adverse early-life exposures have a lasting negative impact on health. Neonatal hyperoxia that is a risk factor for bronchopulmonary dysplasia confers susceptibility to influenza A virus (IAV) infection later in life. Given our previous findings that the circadian clock protects against IAV, we asked if the long-term impact of neonatal hyperoxia vis-à-vis IAV infection includes circadian disruption. Here, we show that neonatal hyperoxia abolishes the clock-mediated time of day protection from IAV in mice, independent of viral burden through host tolerance pathways. We discovered that the lung intrinsic clock (and not the central or immune clocks) mediated this dysregulation. Loss of circadian protein, Bmal1, in alveolar type 2 (AT2) cells recapitulates the increased mortality, loss of temporal gating, and other key features of hyperoxia-exposed animals. Our data suggest a novel role for the circadian clock in AT2 cells in mediating long-term effects of early-life exposures to the lungs.

Respiratory distress syndrome and bronchopulmonary dysplasia after fetal growth restriction: Lessons from a natural experiment in identical twins

BACKGROUND

Fetal growth restriction (FGR) is thought to negatively affect lung development resulting in increased respiratory morbidity. However, research performed in singletons is often limited by a certain level of bias caused by individual differences in genetic constitution, obstetrical and maternal factors.

METHODS

Respiratory morbidity was compared between the smaller and the larger twin in monochorionic twins with selective fetal growth restriction (sFGR), defined as a birth weight discordance ≥ 20%, born in our center between 2010 and 2019 in this retrospective study. Respiratory distress syndrome (RDS) was diagnosed based on the clinical picture of a neonate with respiratory failure requiring mechanical ventilation and/or surfactant, confirmed by a chest X-ray. Bronchopulmonary dysplasia (BPD) was diagnosed when the neonate required treatment with >21% oxygen for at least 28 days.

FINDINGS

Median gestational age at birth for the 94 included pregnancies was 32.4 (IQR 30.4-34.3) weeks. Within-pair analyses showed that the prevalence of RDS was lower in the smaller twin compared to the larger twin, 19.1% (18/94) vs 34.0% (32/94), respectively (p = 0.004). The odds of RDS for the larger twin was doubled (OR 2.1 (CI95% 1.3-3.5). In contrast, the rate of BPD in the smaller twin was higher as opposed to the larger twin, 16.7% (15/90) vs 6.7% (6/89), respectively (p = 0.008), with a more than doubled odds (OR 2.5 (CI95% 1.3-4.9)).

INTERPRETATION

Despite being genetically identical, sFGR twins have different respiratory outcomes. Adverse growth condition in utero in the smaller twin is associated with a reduced odds of RDS at birth but a more than doubled odds of BPD, reflecting the pathophysiologic adverse effect of growth restriction on lung development.

FUNDING

The Dutch Heart Foundation (2017T075).

Pulmonary Outcomes in Children Born Extremely and Very Preterm at 11 Years of Age

Background: There is increasing evidence of prematurity being a risk factor for long-term respiratory outcomes regardless the presence of bronchopulmonary dysplasia (BPD). Aim: To assess the effect of prematurity on respiratory outcomes in children born ≤32 weeks of gestational age at 11 years of age. Materials and Methods: Fifty five ex-preterm children (≤ 32 weeks of gestational age), born in Chieti between January 1, 2006 and December 31, 2007, performed lung function and diffusing capacity test (DLCO) at 11 years of age. Furthermore, allergy evaluation by skin prick test (SPT), eosinophil blood count and assessment of eosinophilic airways inflammation by exhaled nitric oxide (FeNO) were performed. The ex-preterm group was compared to an age- and sex-matched group of term children. Results: No difference for atopic and respiratory medical history was found between ex-preterm children and term controls, except for preschool wheezing that resulted more frequent in ex-preterm children. No difference neither in school-aged asthma frequency nor in lung function assessment at 11 years of age was found between the two groups. Lower DLCO values in ex-preterm children compared to term controls regardless the presence of BPD were found; furthermore, we showed a positive association between DLCO and gestational age. Eosinophil blood count, positive SPTs and FeNO values were similar between the two groups. Conclusions: Diffusing lung capacity was decreased in ex-preterm children at 11 years of age in the absence of lung function impairment and eosinophil airway inflammation, suggesting a non-eosinophilic pattern underlying pulmonary alterations. It could be desirable to include the diffusing capacity assessment in follow-up evaluation of all ex-preterm children.

Effect of a new respiratory care bundle on bronchopulmonary dysplasia in preterm neonates

The development of devices that can fix the tidal volume in high-frequency oscillatory ventilation (HFOV) has allowed for a significant improvement in the management of HFOV. At our institution, this had led to the earlier use of HFOV and promoted a change in the treatment strategy involving the use of higher frequencies (above 15 Hz) and lower high-frequency tidal volumes (VThf). The purpose of this observational study was to assess how survival without bronchopulmonary dysplasia grades 2 and 3 (SF-BPD) is influenced by these modifications in the respiratory strategy applied to preterm infants (gestational age < 32 weeks at birth) who required mechanical ventilation (MV) in the first 3 days of life. We compared a baseline period (2012-2013) against a period in which this strategy had been fully implemented (2016-2017). A total of 182 patients were exposed to MV in the first 3 days of life being a higher proportion on HFOV at day 3 in the second period 79.5% (n 35) in 2016-2017 vs 55.4% (n 31) in 2012-2013. After adjusting for perinatal risk factors, the second period is associated with an increased rate of SF-BPD (OR 2.28; CI 95% 1.072-4.878); this effect is more evident in neonates born at a gestational age of less than 29 weeks (OR 4.87; 95% CI 1.9-12.48).Conclusions : The early use of HFOV combined with the use of higher frequencies and very low VT was associated with an increase in the study population's SF-BPD. What is Known: • High-frequency ventilation with volume guarantee improve ventilation stability and has been shown to reduce lung damage in animal models. What is New: • The strategy of an earlier use of high-frequency oscillatory ventilation combined with the use of higher frequencies and lower tidal volume is associated to an increase in survival without bronchopulmonary dysplasia in our population of preterm infants.