Pulmonary outcomes in adults with a history of Bronchopulmonary Dysplasia differ from patients with asthma

Cohort-based strategies as an in-house tool to evaluate and improve phenotyping robustness of LC-MS/MS lipidomics platforms

In recent years, instrumental improvements have enabled the spread of mass spectrometry-based lipidomics platforms in biomedical research. In mass spectrometry, the reliability of generated data varies for each compound, contingent on, among other factors, the availability of labeled internal standards. It is challenging to evaluate the data for lipids without specific labeled internal standards, especially when dozens to hundreds of lipids are measured simultaneously. Thus, evaluation of the performance of these platforms at the individual lipid level in interlaboratory studies is generally not feasible in a time-effective manner. Herein, using a focused subset of sphingolipids, we present an in-house validation methodology for individual lipid reliability assessment, tailored to the statistical analysis to be applied. Moreover, this approach enables the evaluation of various methodological aspects, including discerning coelutions sharing identical selected reaction monitoring transitions, pinpointing optimal labeled internal standards and their concentrations, and evaluating different extraction techniques. While the full validation according to analytical guidelines for all lipids included in a lipidomics method is currently not possible, this process shows areas to focus on for subsequent method development iterations as well as the robustness of data generated across diverse methodologies.

Recombinant fragment of human surfactant protein D to prevent neonatal chronic lung disease (RESPONSE): a protocol for a phase I safety trial in a tertiary neonatal unit

INTRODUCTION

Chronic respiratory morbidity from bronchopulmonary dysplasia (BPD) remains the most common complication of preterm birth and has consequences for later respiratory, cardiovascular and neurodevelopmental outcomes. The early phases of respiratory illness are characterised by rapid consumption of endogenous surfactant and slow replenishment. Exogenous surfactant is routinely administered to infants born before 28 weeks of gestation as prophylaxis. Endogenous surfactant includes four proteins, known as surfactant proteins (SPs) A, B, C and D. Current bovine-derived and porcine-derived surfactant preparations only contain SPs B and C. SP-D has a key role in lung immune homeostasis as part of the innate immune system. Laboratory studies using recombinant SP-D have demonstrated reduced inflammation, which may be a pathway to reducing the associated morbidity from BPD. RESPONSE uses a recombinant fragment of human SP D (rfhSP-D), in a phase I safety and dose-escalation trial as the first stage in determining its effect in humans.

METHODS AND ANALYSIS

This is a single-centre, dose-escalation, phase I safety study aiming to recruit 24 infants born before 30 weeks gestation with respiratory distress syndrome. In addition to routine surfactant replacement therapy, participants will receive three doses of rfhSP-D via endotracheal route at either 1 mg/kg, 2 mg/kg or 4 mg/kg. The study uses a Bayesian continual reassessment method to make dose escalation decisions. Dose-limiting events (DLE) in this trial will be graded according to the published Neonatal Adverse Event Severity Score. The primary outcome of this study is to evaluate the safety profile of rfhSP-D across each dose level based on the profile of DLE to establish the recommended phase 2 dose (RP2D) of rfhSP-D.

ETHICS AND DISSEMINATION

The RESPONSE study has received ethical approval from London-Brent NHS Research Health Authority ethics committee. Results from the study will be published in peer-reviewed journals and presented at national and international conferences.

TRIAL REGISTRATION NUMBERS

ISRCTN17083028, NCT05898633.

PROTOCOL VERSION

RESPONSE Protocol V.4.0 24th July 2024.

Expiratory airflow limitation in adults born extremely preterm: A systematic review and meta-analysis

Extreme preterm (EP) birth, denoting delivery before the onset of the third trimester, interrupts intrauterine development and causes significant early-life pulmonary trauma, thereby posing a lifelong risk to respiratory health. We conducted a systematic review and meta-analysis to investigate adult lung function following EP birth (gestational age <28 weeks); comparing forced expiratory volume in first second (FEV1), forced vital capacity (FVC), and FEV1/FVC to reference values. Subgroup differences were explored based on timing of birth relative to surfactant use (1991) and bronchopulmonary dysplasia (BPD) status. Systematic searches were performed in Medline, EMBASE, Web of Science and Cochrane Central. Quality assessments were carried out using a modified Newcastle-Ottawa Scale for cohort studies. Sixteen studies encompassing 1036 EP-born adults were included, with 14 studies (n = 787) reporting data as %predicted, and 11 (n = 879) as z-score (not mutually exclusive). Overall mean [95 % confidence interval (CI)] %FEV1 was 85.30 (82.51; 88.09), %FVC was 94.33 (91.74; 96.91), and FEV1/FVC was 79.54 (77.71 to 81.38), all three with high heterogeneity. Overall mean (95 %CI) zFEV1 was -1.05 (-1.21; -0.90) and zFVC was. -0.45 (-0.59; -0.31), both with moderate heterogeneity. Subgroup analyses revealed no difference in FEV1 before versus after widespread use of surfactant, but more impairments after neonatal BPD. This meta-analysis revealed significant airflow limitation in EP-born adults, mostly explained by those with neonatal BPD. FEV1 was more reduced than FVC, and FEV1/FVC was at the lower limit of normal. Although at a group level, most adult EP-born individuals do not meet COPD criteria, these findings are concerning.

Approaches to Interdisciplinary Care for Infants with Severe Bronchopulmonary Dysplasia: A Survey of the Bronchopulmonary Dysplasia Collaborative

OBJECTIVE

Bronchopulmonary dysplasia (BPD) remains the most common late morbidity for extremely premature infants. Care of infants with BPD requires a longitudinal approach from the neonatal intensive care unit to ambulatory care though interdisciplinary programs. Current approaches for the development of optimal programs vary among centers.

STUDY DESIGN

We conducted a survey of 18 academic centers that are members of the BPD Collaborative, a consortium of institutions with an established interdisciplinary BPD program. We aimed to characterize the approach, composition, and current practices of the interdisciplinary teams in inpatient and outpatient domains.

RESULTS

Variations exist among centers, including composition of the interdisciplinary team, whether the team is the primary or consult service, timing of the first team assessment of the patient, frequency and nature of rounds during the hospitalization, and the timing of ambulatory visits postdischarge.

CONCLUSION

Further studies to assess long-term outcomes are needed to optimize interdisciplinary care of infants with severe BPD.

KEY POINTS

· Care of infants with BPD requires a longitudinal approach from the NICU to ambulatory care.. · Benefits of interdisciplinary care for children have been observed in other chronic conditions.. · Current approaches for the development of optimal interdisciplinary BPD programs vary among centers..

Prematurity-associated lung disease: is it asthma?

Not all wheeze is "asthma" in those born very preterm. Further work is needed to better understand the aetiology of prematurity-associated lung disease and the best treatments for this population. https://bit.ly/3Tko3vi.

Bronchopulmonary dysplasia in adults: Exploring pathogenesis and phenotype

This review highlights both the longstanding impact of bronchopulmonary dysplasia (BPD) on the health of adult survivors of prematurity and the pressing need for prospective, longitudinal studies of this population. Conservatively, there are an estimated 1,000,000 survivors of BPD in the United States alone. Unfortunately, most of the available literature regarding outcomes of lung disease due to prematurity naturally focuses on pediatric patients in early or middle childhood, and the relative amount of literature on adult survivors is scant. As the number of adult survivors of BPD continues to increase, it is essential that both adult and pediatric pulmonologists have a comprehensive understanding of the pathophysiology and underlying disease process, including the molecular signaling pathways and pro-inflammatory modulators that contribute to the pathogenesis of BPD. We summarize the most common presenting symptoms for adults with BPD and identify the critical challenges adult pulmonologists face in managing the care of survivors of prematurity. Specifically, these challenges include the wide variability of the clinical presentation of adult patients, comorbid cardiopulmonary complications, and the paucity of longitudinal data available on these patients. Adult survivors of BPD have even required lung transplantation, indicating the high burden of morbidity that can result from premature birth and subsequent lung injury. In addition, we analyze the disparate symptoms and management approach to adults with "old" BPD versus "new" BPD. The aim of this review is to assist pulmonologists in understanding the underlying pathophysiology of BPD and to improve clinical recognition of this increasingly common pulmonary disease.

Large airway T cells in adults with former bronchopulmonary dysplasia

BACKGROUND

Bronchopulmonary Dysplasia (BPD) in infants born prematurely is a risk factor for chronic airway obstruction later in life. The distribution of T cell subtypes in the large airways is largely unknown.

OBJECTIVE

To characterize cellular and T cell profiles in the large airways of young adults with a history of BPD.

METHODS

Forty-three young adults born prematurely (preterm (n = 20), BPD (n = 23)) and 45 full-term-born (asthma (n = 23), healthy (n = 22)) underwent lung function measurements, and bronchoscopy with large airway bronchial wash (BW). T-cells subsets in BW were analyzed by immunocytochemistry.

RESULTS

The proportions of both lymphocytes and CD8 + T cells in BW were significantly higher in BPD (median, 6.6%, and 78.0%) when compared with asthma (3.4% and 67.8%, p = 0.002 and p = 0.040) and healthy (3.8% and 40%, p < 0.001 and p < 0.001). In all adults born prematurely (preterm and BPD), lymphocyte proportion correlated negatively with forced vital capacity (r= -0.324, p = 0.036) and CD8 + T cells correlated with forced expiratory volume in one second, FEV1 (r=-0.448, p = 0.048). Correlation-based network analysis revealed that lung function cluster and BPD-birth cluster were associated with lymphocytes and/or CD4 + and CD8 + T cells. Multivariate regression analysis showed that lymphocyte proportions and BPD severity qualified as independent factors associated with FEV1.

CONCLUSIONS

The increased cytotoxic T cells in the large airways in young adults with former BPD, suggest a similar T-cell subset pattern as in the small airways, resembling features of COPD. Our findings strengthen the hypothesis that mechanisms involving adaptive and innate immune responses are involved in the development of airway disease due to preterm birth.

Unravelling the respiratory health path across the lifespan for survivors of preterm birth

Many survivors of preterm birth will have abnormal lung development, reduced peak lung function and, potentially, an increased rate of physiological lung function decline, each of which places them at increased risk of chronic obstructive pulmonary disease across the lifespan. Current rates of preterm birth indicate that by the year 2040, around 50 years since the introduction of surfactant therapy, more than 700 million individuals will have been born prematurely-a number that will continue to increase by about 15 million annually. In this Personal View, we describe current understanding of the impact of preterm birth on lung function through the life course, with the aim of putting this emerging health crisis on the radar for the respiratory community. We detail the potential underlying mechanisms of prematurity-associated lung disease and review current approaches to prevention and management. Furthermore, we propose a novel way of considering lung disease after preterm birth, using a multidimensional model to determine individual phenotypes of lung disease-a first step towards optimising management approaches for prematurity-associated lung disease.

Lung function deficits and bronchodilator responsiveness at 12 years of age in children born very preterm compared with controls born at term

INTRODUCTION

Very preterm birth is associated with lung function impairment later in life, but several aspects have not been studied. We aimed to comprehensively assess lung function at school age in very preterm infants and term controls, with special emphasis on bronchopulmonary dysplasia (BPD), sex, and bronchodilator response.

METHODS

At 12 years of age, 136 children born very preterm (85 with and 51 without BPD) and 56 children born at term performed spirometry, body plethysmography, impulse oscillometry, measurement of diffusion capacity, and multiple breath washout, before and after bronchodilator inhalation.

RESULTS

Airway symptoms and a diagnosis of asthma were more common in children born very preterm. These children had more airflow limitation, seen as lower forced expiratory volume in 1 s (FEV1 ) (p < .001), FEV1 /forced vital capacity (FVC) (p = .011), and mean forced expiratory flow between 25% and 75% of FVC (p < .001), and a higher total and peripheral airway resistance compared with term-born controls. There was no difference in total lung capacity but air trapping and lung clearance index were higher in children born very preterm. Diffusion capacity was lower in children born very preterm, especially in those with a diagnosis of BPD. In most other tests, the differences between preterm-born children with or without BPD were smaller than between children born preterm versus at term. Boys born preterm had more lung function deficits than preterm-born girls. In children born very preterm, airway obstruction was to a large extent reversible.

CONCLUSION

At 12 years of age, children born very preterm had lower lung function than children born at term in most aspects and there was only little difference between children with or without BPD. Airway obstruction improved markedly after bronchodilator inhalation.

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.

Multidisciplinary bronchopulmonary dysplasia care

INTRODUCTION

Bronchopulmonary dysplasia (BPD) is a chronic respiratory disease in neonates and infants, which often presents with multisystem organ involvement, co-morbidities, and prolonged hospital stays. Therefore, a multidisciplinary chronic care approach is needed in the severest forms of BPD to optimize outcomes. However, this approach can be challenging to implement. The objective of this article is to review and synthesize the available literature regarding multidisciplinary care in infants and children with established BPD, and to provide a framework that can guide clinical practice and future research.

AREAS COVERED

A literature search was conducted using Ovid MEDLINE, CINAHL, and Embase and several components of multidisciplinary management of BPD were identified and reviewed, including chronic care, team development, team members, discharge planning, and outpatient care.

EXPERT OPINION

Establishing a core multidisciplinary group familiar with the chronicity of established BPD is recommended as best practice for this population. Acknowledging this is not feasible for all individual centers, it is important for clinical practice and future research to focus on the development and incorporation of national consulting services, telemedicine, and educational resources.

Increasing airway obstruction through life following bronchopulmonary dysplasia: a meta-analysis

Background

Few studies exist investigating lung function trajectories of those born preterm; however growing evidence suggests some individuals experience increasing airway obstruction throughout life. Here we use the studies identified in a recent systematic review to provide the first meta-analysis investigating the impact of preterm birth on airway obstruction measured by the forced expiratory volume in 1 s (FEV1) to forced vital capacity (FVC) ratio.

Methods

Cohorts were included for analysis if they reported FEV1/FVC in survivors of preterm birth (<37 weeks' gestation) and control populations born at term. Meta-analysis was performed using a random effect model, expressed as standardised mean difference (SMD). Meta-regression was conducted using age and birth year as moderators.

Results

55 cohorts were eligible, 35 of which defined groups with bronchopulmonary dysplasia (BPD). Compared to control populations born at term, lower values of FEV1/FVC were seen in all individuals born preterm (SMD -0.56), with greater differences seen in those with BPD (SMD -0.87) than those without BPD (SMD -0.45). Meta-regression identified age as a significant predictor of FEV1/FVC in those with BPD with the FEV1/FVC ratio moving -0.04 sds away from the term control population for every year of increased age.

Conclusions

Survivors of preterm birth have significantly increased airway obstruction compared to those born at term with larger differences in those with BPD. Increased age is associated with a decline in FEV1/FVC values suggesting increased airway obstruction over the life course.

Preterm Birth, Developmental Smoke/Nicotine Exposure, and Life-Long Pulmonary Sequelae

This review delineates the main pulmonary issues related to preterm birth, perinatal tobacco/nicotine exposure, and its effects on offspring, focusing on respiratory health and its possible transmission to subsequent generations. We review the extent of the problem of preterm birth, prematurity-related pulmonary effects, and the associated increased risk of asthma later in life. We then review the impact of developmental tobacco/nicotine exposure on offspring asthma and the significance of transgenerational pulmonary effects following perinatal tobacco/nicotine exposure, possibly via its effects on germline epigenetics.

Geographical Differences and Temporal Improvements in Forced Expiratory Volume in 1 Second of Preterm-Born Children: A Systematic Review and Meta-analysis

Importance

Although preterm birth is associated with later deficits in lung function, there is a paucity of information on geographical differences and whether improvements occur over time, especially after surfactant was introduced.

Objective

To determine deficits in percentage predicted forced expiratory volume in 1 second (%FEV1) in preterm-born study participants, including those with bronchopulmonary dysplasia (BPD) in infancy, when compared with term-born control groups.

Data Sources

Eight databases searched up to December 2021.

Study Selection

Studies reporting spirometry for preterm-born participants with or without a term-born control group were identified.

Data Extraction and Synthesis

Data were extracted and quality assessed by 1 reviewer and checked by another. Data were pooled using random-effects models and analyzed using Review Manager and the R metafor package.

Main Outcomes and Measures

Deficits in %FEV1 between preterm-born and term groups. Associations between deficits in %FEV1 and year of birth, age, introduction of surfactant therapy, and geographical region of birth and residence were also assessed.

Results

From 16 856 titles, 685 full articles were screened: 86 with and without term-born control groups were included. Fifty studies with term controls were combined with the 36 studies from our previous systematic review, including 7094 preterm-born and 17 700 term-born participants. Of these studies, 45 included preterm-born children without BPD, 29 reported on BPD28 (supplemental oxygen dependency at 28 days), 26 reported on BPD36 (supplemental oxygen dependency at 36 weeks' postmenstrual age), and 86 included preterm-born participants. Compared with the term-born group, the group of all preterm-born participants (all preterm) had deficits of %FEV1 of -9.2%; those without BPD had deficits of -5.8%, and those with BPD had deficits of approximately -16% regardless of whether they had BPD28 or BPD36. As year of birth increased, there was a statistically significant narrowing of the difference in mean %FEV1 between the preterm- and term-born groups for the all preterm group and the 3 BPD groups but not for the preterm-born group without BPD. For the all BPD group, when compared with Scandinavia, North America and western Europe had deficits of -5.5% (95% CI, -10.7 to -0.3; P = .04) and -4.1% (95% CI, -8.8 to 0.5; P = .08), respectively.

Conclusions and Relevance

Values for the measure %FEV1 were reduced in preterm-born survivors. There were improvements in %FEV1 over recent years, but geographical region had an association with later %FEV1 for the BPD groups.

Bronchodilator responsiveness and dysanapsis in bronchopulmonary dysplasia

Background

The incidence of bronchopulmonary dysplasia (BPD) following preterm birth is increasing. Bronchodilators are often used to treat patients with BPD with little evidence to guide therapy. The aim of this study was to test the hypothesis that there are infant pulmonary function test (iPFT) parameters that can predict subsequent bronchodilator response in infants with BPD.

Methods

Subjects in this study were part of a patient group in which we reported three BPD phenotypes (obstructive, restrictive and mixed) based on iPFT data. From that group, a cohort of 93 patients with iPFT data including bronchodilator response was eligible for this study.

Results

Bronchodilator responsiveness was found in 59 people (63%) in the cohort. There were no differences in demographics between the responders and non-responders. There was no difference in forced vital capacity (FVC) between the two groups. Responders had significantly lower forced expiratory volume in 0.5 s (FEV0.5) and FEV0.5/FVC (p<0.005) and greater indices of hyperinflation than did non-responders (p<0.005). Logistic regression modelling found that pre-bronchodilator FEV0.5 and functional residual capacity/total lung capacity were significantly associated with bronchodilator response. The magnitude of response to bronchodilators was negatively correlated (R= −0.49, R2= 0.24, p<0.001) with the FEV0.5. The median dysanapsis ratio in responders (0.08, 95% CI 0.05–0.19) was significantly (p=0.005) smaller than in non-responders (0.18, 95% CI 0.06–0.38).

Conclusion

These findings demonstrate that there are pulmonary function test parameters associated with bronchodilator response. Responders had evidence of greater dysanaptic lung growth than non-responders.

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.

Increased cytotoxic T-cells in the airways of adults with former bronchopulmonary dysplasia

Rationale

Bronchopulmonary dysplasia (BPD) in preterm-born infants is a risk factor for chronic airway obstruction in adulthood. Cytotoxic T-cells are implicated in COPD, but their involvement in BPD is not known.

Objectives

To characterise the distribution of airway T-cell subsets in adults with a history of BPD.

Methods

Young adults with former BPD (n=22; median age 19.6 years), age-matched adults born preterm (n=22), patients with allergic asthma born at term (n=22) and healthy control subjects born at term (n=24) underwent bronchoalveolar lavage (BAL). T-cell subsets in BAL were analysed using flow cytometry.

Results

The total number of cells and the differential cell counts in BAL were similar among the study groups. The percentage of CD3⁺CD8⁺ T-cells was higher (p=0.005) and the proportion of CD3⁺CD4⁺ T-cells was reduced (p=0.01) in the BPD group, resulting in a lower CD4/CD8 ratio (p=0.007) compared to the healthy controls (median 2.2 versus 5.3). In BPD and preterm-born study subjects, both CD3⁺CD4⁺ T-cells (r_s=0.38, p=0.03) and CD4/CD8 ratio (r_s=0.44, p=0.01) correlated positively with forced expiratory volume in 1 s (FEV₁). Furthermore, CD3⁺CD8⁺ T-cells were negatively correlated with both FEV₁ and FEV₁/forced vital capacity (r_s= −0.44, p=0.09 and r_s= −0.41, p=0.01, respectively).

Conclusions

Young adults with former BPD have a T-cell subset pattern in the airways resembling features of COPD. Our findings are compatible with the hypothesis that CD3⁺CD8⁺ T-cells are involved in mechanisms behind chronic airway obstruction in these patients.

Young adults with former BPD display more cytotoxic T-cells in the airways than healthy subjects. These T-cells correlate with FEV₁. Thus, cytotoxic T-cells may contribute to the pathology behind chronic airway obstruction in adults with former BPD.https://bit.ly/3soI4lK

Macitentan attenuates cardiovascular remodelling in infant rats with chronic lung disease

Background

Cardiovascular impairment contributes to increased mortality in preterm infants with chronic lung disease. Macitentan, an endothelin-1 receptor antagonist, has the potential to attenuate pulmonary and cardiovascular remodelling.

Methods

In a prospective randomized placebo-controlled intervention trial, Sprague–Dawley rats were exposed to 0.21 or 1.0 fraction of inspired oxygen (FiO2) for 19 postnatal days. Rats were treated via gavage with placebo or macitentan from days of life 5 to 19. Alveoli, pulmonary vessels, α-smooth muscle actin content in pulmonary arterioles, size of cardiomyocytes, right to left ventricular wall diameter ratio, and endothelin-1 plasma concentrations were assessed.

Results

FiO2 1.0 induced typical features of chronic lung disease with significant alveolar enlargement (p = 0.012), alveolar (p = 0.048) and pulmonary vessel rarefaction (p = 0.024), higher α-smooth muscle actin content in pulmonary arterioles (p = 0.009), higher right to left ventricular wall diameter ratio (p = 0.02), and larger cardiomyocyte cross-sectional area (p < 0.001). Macitentan treatment significantly increased pulmonary vessel count (p = 0.004) and decreased right to left ventricular wall diameter ratios (p = 0.002). Endothelin-1 plasma concentrations were higher compared to placebo (p = 0.015). Alveolar number and size, α-smooth muscle actin, and the cardiomyocyte cross-sectional area remained unchanged (all p > 0.05).

Conclusion

The endothelin-1 receptor antagonist macitentan attenuated cardiovascular remodelling in an infant rat model for preterm chronic lung disease. This study underscores the potential of macitentan to reduce cardiovascular morbidity in preterm infants with chronic lung disease.

Pulmonary Magnetic Resonance Imaging of Ex-preterm Children with/without Bronchopulmonary Dysplasia

RATIONALE

Children born prematurely, particularly those with bronchopulmonary dysplasia, have persisting lung abnormalities requiring longitudinal monitoring. Pulmonary ultra-short echo time magnetic resonance imaging (MRI) measurements may provide sensitive markers of persisting lung abnormalities, and have not been evaluated in school-aged children born prematurely.

OBJECTIVE

To compare pulmonary MRI and pulmonary function test measurements in preterm-born school-aged children with and without bronchopulmonary dysplasia.

METHODS

Children aged 7-9 years, born extremely preterm, with and without bronchopulmonary dysplasia, were recruited from three centers. Participants underwent pulmonary ultra-short echo time MRI and pulmonary function tests. Primary outcomes included total proton density and proton density at full expiration, measured using MRI. Multiple linear regression analysis was performed, adjusting for gestational age and bronchopulmonary dysplasia. Associations between MRI and pulmonary function were tested.

RESULTS

Thirty-five children were included in the primary analysis (24 with bronchopulmonary dysplasia, 11 without); 29 completed pulmonary function tests, of whom 11 (38%) had airflow limitation. Children with bronchopulmonary dysplasia had 44% (CI: 10%, 66%) lower mean total proton density (mean ± SD: 3.6 ± 2.6) compared to those without (6.1 ± 4.0). Those with bronchopulmonary dysplasia had 25% (CI: 3%, 42%) lower proton density at full expiration than those without. Lower total proton density and proton density at full expiration were moderately correlated with greater residual volume, residual volume/total lung capacity, and lung clearance index (Spearman correlations for total proton density: -0.42, -0.57, and -0.53, respectively. Spearman correlations for proton density at full expiration: -0.28, -0.57, and -0.45, respectively).

CONCLUSIONS

School-aged preterm-born children with bronchopulmonary dysplasia have parenchymal tissue abnormalities measured using ultrashort MRI proton density, compared to those without. MRI proton density correlated with pulmonary function measures indicative of gas trapping. Clinical trial registered with ClinicalTrials.gov (NCT02921308).

Outpatient Respiratory Management of Infants, Children, and Adolescents with Post-Prematurity Respiratory Disease: An Official American Thoracic Society Clinical Practice Guideline

Background: Premature birth affects millions of neonates each year, placing them at risk for respiratory disease due to prematurity. Bronchopulmonary dysplasia is the most common chronic lung disease of infancy, but recent data suggest that even premature infants who do not meet the strict definition of bronchopulmonary dysplasia can develop adverse pulmonary outcomes later in life. This post-prematurity respiratory disease (PPRD) manifests as chronic respiratory symptoms, including cough, recurrent wheezing, exercise limitation, and reduced pulmonary function. This document provides an evidence-based clinical practice guideline on the outpatient management of infants, children, and adolescents with PPRD. Methods: A multidisciplinary panel of experts posed questions regarding the outpatient management of PPRD. We conducted a systematic review of the relevant literature. The Grading of Recommendations, Assessment, Development, and Evaluation approach was used to rate the quality of evidence and the strength of the clinical recommendations. Results: The panel members considered the strength of each recommendation and evaluated the benefits and risks of applying the intervention. In formulating the recommendations, the panel considered patient and caregiver values, the cost of care, and feasibility. Recommendations were developed for or against three common medical therapies and four diagnostic evaluations in the context of the outpatient management of PPRD. Conclusions: The panel developed recommendations for the outpatient management of patients with PPRD on the basis of limited evidence and expert opinion. Important areas for future research were identified.

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

BACKGROUND

Chorioamnionitis, an intrauterine infection of the placenta and fetal membranes, is a common risk factor for adverse pulmonary outcomes in premature infants including BPD, which is characterized by an arrest in alveolar development. As endogenous epithelial stem/progenitor cells are crucial for organogenesis and tissue repair, we examined whether intrauterine inflammation negatively affects these essential progenitor pools.

METHODS

In an ovine chorioamnionitis model, fetuses were intra-amniotically exposed to LPS, 2d or 7d (acute inflammation) before preterm delivery at 125d of gestation, or to intra-amniotic Ureaplasma parvum for 42d (chronic inflammation). Lung function, pulmonary endogenous epithelial stem/progenitor pools, and downstream functional markers were studied.

RESULTS

Lung function was improved in the 7d LPS and 42d Ureaplasma groups. However, intrauterine inflammation caused a loss of P63+ basal cells in proximal airways and reduced SOX-9 expression and TTF-1+ Club cells in distal airways. Attenuated type-2 cell numbers were associated with lower proliferation and reduced type-1 cell marker Aqp5 expression, indicative for impaired progenitor function. Chronic Ureaplasma infection only affected distal airways, whereas acute inflammation affected stem/progenitor populations throughout the lungs.

CONCLUSIONS

Acute and chronic prenatal inflammation improve lung function at the expense of stem/progenitor alterations that potentially disrupt normal lung development, thereby predisposing to adverse postnatal outcomes.

IMPACT

In this study, prenatal inflammation improved lung function at the expense of stem/progenitor alterations that potentially disrupt normal lung development, thereby predisposing to adverse postnatal outcomes. Importantly, we demonstrate that these essential alterations can already be initiated before birth. So far, stem/progenitor dysfunction has only been shown postnatally. This study indicates that clinical protocols to target the consequences of perinatal inflammatory stress for the immature lungs should be initiated as early as possible and ideally in utero. Within this context, our data suggest that interventions, which promote function or repair of endogenous stem cells in the lungs, hold great promise.

Functional respiratory imaging provides novel insights into the long-term respiratory sequelae of bronchopulmonary dysplasia

RATIONALE

Bronchopulmonary dysplasia (BPD) is a common complication of preterm birth. Lung function and imaging are classically used to assess BPD. Functional respiratory imaging (FRI) combines a structural and functional assessment of the airways and their vasculature. We aimed to assess BPD using FRI and to correlate these findings with the clinical presentation.

METHODS

We included 37 adolescents with a history of preterm birth (22 BPD cases and 15 preterm controls). The study protocol included a detailed history, lung function testing and computed tomography (CT) (at total lung capacity (TLC) and functional residual capacity (FRC)) with FRI. CT images were also assessed using the Aukland scoring system.

RESULTS

BPD patients had lower forced expiratory volume in 1 s to forced vital capacity ratio (p=0.02) and impaired diffusion capacity (p=0.02). Aukland CT scores were not different between the two groups. FRI analysis showed higher lobar volumes in BPD patients at FRC (p<0.01), but not at TLC. Airway resistance was significantly higher in the BPD group, especially in the distal airways. Additionally, FRI showed more air trapping in BPD patients, in contrast to findings on conventional CT images.

CONCLUSION

This study is the first to use FRI in research for BPD. FRI analysis showed higher lobar volumes in BPD patients, indicating air trapping and reduced inspiratory capacity. In contrast to Aukland CT scores, FRI showed more air trapping in the BPD group, suggesting that FRI might be a more sensitive detection method. Importantly, we also showed increased distal airway resistance in BPD patients. By combining structural and functional assessment, FRI may help to better understand the long-term sequelae of BPD.

Lung function trajectories in children with post-prematurity respiratory disease: identifying risk factors for abnormal growth

Background

Survivors of prematurity are at risk for abnormal childhood lung function. Few studies have addressed trajectories of lung function and risk factors for abnormal growth in childhood. This study aims to describe changes in lung function in a contemporary cohort of children born preterm followed longitudinally in pulmonary clinic for post-prematurity respiratory disease and to assess maternal and neonatal risk factors associated with decreased lung function trajectories.

Methods

Observational cohort of 164 children born preterm ≤ 32 weeks gestation followed in pulmonary clinic at Boston Children’s Hospital with pulmonary function testing. We collected demographics and neonatal history. We used multivariable linear regression to identify the impact of neonatal and maternal risk factors on lung function trajectories in childhood.

Results

We identified 264 studies from 82 subjects with acceptable longitudinal FEV₁ data and 138 studies from 47 subjects with acceptable longitudinal FVC and FEV₁/FVC data. FEV₁% predicted and FEV₁/FVC were reduced compared to childhood norms. Growth in FVC outpaced FEV₁, resulting in an FEV₁/FVC that declined over time. In multivariable analyses, longer duration of mechanical ventilation was associated with a lower rate of rise in FEV₁% predicted and greater decline in FEV₁/FVC, and postnatal steroid exposure in the NICU was associated with a lower rate of rise in FEV₁ and FVC % predicted. Maternal atopy and asthma were associated with a lower rate of rise in FEV₁% predicted.

Conclusions

Children with post-prematurity respiratory disease demonstrate worsening obstruction in lung function throughout childhood. Neonatal risk factors including exposure to mechanical ventilation and postnatal steroids, as well as maternal atopy and asthma, were associated with diminished rate of rise in lung function. These results may have implications for lung function trajectories into adulthood.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01720-0.

Glutathione S-transferases and their implications in the lung diseases asthma and chronic obstructive pulmonary disease: Early life susceptibility?

Our lungs are exposed daily to airborne pollutants, particulate matter, pathogens as well as lung allergens and irritants. Exposure to these substances can lead to inflammatory responses and may induce endogenous oxidant production, which can cause chronic inflammation, tissue damage and remodeling. Notably, the development of asthma and Chronic Obstructive Pulmonary Disease (COPD) is linked to the aforementioned irritants. Some inhaled foreign chemical compounds are rapidly absorbed and processed by phase I and II enzyme systems critical in the detoxification of xenobiotics including the glutathione-conjugating enzymes Glutathione S-transferases (GSTs). GSTs, and in particular genetic variants of GSTs that alter their activities, have been found to be implicated in the susceptibility to and progression of these lung diseases. Beyond their roles in phase II metabolism, evidence suggests that GSTs are also important mediators of normal lung growth. Therefore, the contribution of GSTs to the development of lung diseases in adults may already start in utero, and continues through infancy, childhood, and adult life. GSTs are also known to scavenge oxidants and affect signaling pathways by protein-protein interaction. Moreover, GSTs regulate reversible oxidative post-translational modifications of proteins, known as protein S-glutathionylation. Therefore, GSTs display an array of functions that impact the pathogenesis of asthma and COPD.

In this review we will provide an overview of the specific functions of each class of mammalian cytosolic GSTs. This is followed by a comprehensive analysis of their expression profiles in the lung in healthy subjects, as well as alterations that have been described in (epithelial cells of) asthmatics and COPD patients. Particular emphasis is placed on the emerging evidence of the regulatory properties of GSTs beyond detoxification and their contribution to (un)healthy lungs throughout life. By providing a more thorough understanding, tailored therapeutic strategies can be designed to affect specific functions of particular GSTs.

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.

Cigarette Smoke Exposure, Pediatric Lung Disease, and COVID-19

The detrimental effects of tobacco exposure on children's health are well known. Nonetheless, the prevalence of secondhand or direct cigarette smoke exposure (CSE) in the pediatric population has not significantly decreased over time. On the contrary, the rapid incline in use of e-cigarettes among adolescents has evoked public health concerns since increasing cases of vaping-induced acute lung injury have highlighted the potential harm of these new "smoking" devices. Two pediatric populations are especially vulnerable to the detrimental effects of cigarette smoke. The first group is former premature infants whose risk is elevated both due to their prematurity as well as other risk factors such as oxygen and mechanical ventilation to which they are disproportionately exposed. The second group is children and adolescents with chronic respiratory diseases, in particular asthma and other wheezing disorders. Coronavirus disease 2019 (COVID-19) is a spectrum of diseases caused by infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that has spread worldwide over the last year. Here, respiratory symptoms ranging from mild to acute respiratory distress syndrome (ARDS) are at the forefront of COVID-19 cases among adults, and cigarette smoking is associated with worse outcomes in this population, and cigarette smoking is associated with worse outcomes in this population. Interestingly, SARS-CoV-2 infection affects children differently in regard to infection susceptibility, disease manifestations, and complications. Although children carry and transmit the virus, the likelihood of symptomatic infection is low, and the rates of hospitalization and death are even lower when compared to the adult population. However, multisystem inflammatory syndrome is recognized as a serious consequence of SARS-CoV-2 infection in the pediatric population. In addition, recent data demonstrate specific clinical patterns in children infected with SARS-CoV-2 who develop multisystem inflammatory syndrome vs. severe COVID-19. In this review, we highlight the pulmonary effects of CSE in vulnerable pediatric populations in the context of the ongoing SARS-CoV-2 pandemic.

High-Precision Automated Workflow for Urinary Untargeted Metabolomic Epidemiology

Urine is a noninvasive biofluid that is rich in polar metabolites and well suited for metabolomic epidemiology. However, because of individual variability in health and hydration status, the physiological concentration of urine can differ >15-fold, which can pose major challenges in untargeted liquid chromatography-mass spectrometry (LC-MS) metabolomics. Although numerous urine normalization methods have been implemented (e.g., creatinine, specific gravity-SG), most are manual and, therefore, not practical for population-based studies. To address this issue, we developed a method to measure SG in 96-well-plates using a refractive index detector (RID), which exhibited accuracy within 85-115% and <3.4% precision. Bland-Altman statistics showed a mean deviation of -0.0001 SG units (limits of agreement: -0.0014 to 0.0011) relative to a hand-held refractometer. Using this RID-based SG normalization, we developed an automated LC-MS workflow for untargeted urinary metabolomics in a 96-well-plate format. The workflow uses positive and negative ionization HILIC chromatography and acquires mass spectra in data-independent acquisition (DIA) mode at three collision energies. Five technical internal standards (tISs) were used to monitor data quality in each method, all of which demonstrated raw coefficients of variation (CVs) < 10% in the quality controls (QCs) and < 20% in the samples for a small cohort (n = 87 urine samples, n = 22 QCs). Application in a large cohort (n = 842 urine samples, n = 248 QCs) demonstrated CVQC < 5% and CVsamples < 16% for 4/5 tISs after signal drift correction by cubic spline regression. The workflow identified >540 urinary metabolites including endogenous and exogenous compounds. This platform is suitable for performing urinary untargeted metabolomic epidemiology and will be useful for applications in population-based molecular phenotyping.

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.

Agreement between spirometry and impulse oscillometry for lung function assessment in 6-year-old children born extremely preterm and at term

BACKGROUND

Extremely preterm birth is a risk factor for reduced lung function later in life, and clinical follow-up from early childhood is recommended. Dynamic spirometry is the most widely used method to assess airway obstruction, but impulse oscillometry (IOS) may be an alternative method that is easier to perform in young children. The feasibility and agreement between spirometry and IOS outcome variables has not been investigated in children born extremely preterm.

AIM

To determine the feasibility of and correlation between spirometry and IOS in pre-school children born extremely preterm.

METHODS

Spirometry and IOS were performed in 6-year-old children born extremely preterm (n = 88) and age-matched term controls (n = 84) in Stockholm, Sweden. Correlations between spirometry and IOS outcome variables were analyzed using Pearson's partial correlation, adjusting for height.

RESULTS

Success rate for spirometry (60%) was lower than for IOS (93%) but did not differ significantly between the preterm and term groups (56% and 64% for spirometry, P = .25; and 92% and 94% for IOS, P = .61). Correlations between spirometry and IOS outcomes were at best moderate (Spearman's r = -0.31 to -0.56). Normal IOS identified 69% to 90% of those with normal spirometry. A negative predictive value of 90% was found for R5-R20 versus FEV_0.75 /FVC, suggesting that IOS may be used to exclude obstructive airway disease as measured by spirometry.

CONCLUSION

IOS is a more feasible method than spirometry to assess lung function in young children irrespective of gestational age at birth and could be considered an alternative in children who cannot perform spirometry.

Neonatal therapy with PF543, a sphingosine kinase 1 inhibitor, ameliorates hyperoxia-induced airway remodeling in a murine model of bronchopulmonary dysplasia

Hyperoxia (HO)-induced lung injury contributes to bronchopulmonary dysplasia (BPD) in preterm newborns. Intractable wheezing seen in BPD survivors is associated with airway remodeling (AWRM). Sphingosine kinase 1 (SPHK1)/sphingosine-1-phosphate (S1P) signaling promotes HO-mediated neonatal BPD; however, its role in the sequela of AWRM is not known. We noted an increased concentration of S1P in tracheal aspirates of neonatal infants with severe BPD, and earlier, demonstrated that Sphk1^-/- mice showed protection against HO-induced BPD. The role of SPHK1/S1P in promoting AWRM following exposure of neonates to HO was investigated in a murine model. Therapy using PF543, the specific SPHK1 inhibitor, during neonatal HO reduced alveolar simplification followed by reduced AWRM in adult mice. This was associated with reduced airway hyperreactivity to intravenous methacholine. Neonatal HO exposure was associated with increased expression of SPHK1 in lung tissue of adult mice, which was reduced with PF543 therapy in the neonatal stage. This was accompanied by amelioration of HO-induced reduction of E-cadherin in airway epithelium. This may be suggestive of arrested partial epithelial mesenchymal transition (EMT) induced by HO. In vitro studies using human primary airway epithelial cells (HAEpCs) showed that SPHK1 inhibition or deletion restored HO-induced reduction in E-cadherin and reduced formation of mitochondrial reactive oxygen species (mtROS). Blocking mtROS with MitoTempo attenuated HO-induced partial EMT of HAEpCs. These results collectively support a therapeutic role for PF543 in preventing HO-induced BPD in neonates and the long-term sequela of AWRM, thus conferring a long-term protection resulting in improved lung development and function.

Chitin Analog AVR-25 Prevents Experimental Bronchopulmonary Dysplasia

Infants born extremely preterm are at a high risk of developing bronchopulmonary dysplasia (BPD) which is characterized by large, simplified alveoli, increased inflammation, disrupted and dysregulated vasculogenesis, decreased cell proliferation, and increased cell death in the lungs. Due to lack of specific drug treatments to combat this condition, BPD and its long-term complications have taken a significant toll of healthcare resources. AVR-25, a novel immune modulator experimental compound, was able to partially recover the pulmonary phenotype in the hyperoxia-induced experimental mouse model of BPD. We anticipate that AVR-25 will have therapeutic potential for managing human BPD.

Lifelong pulmonary sequelae of bronchopulmonary dysplasia

PURPOSE OF REVIEW

To summarize the current literature evaluating long-term pulmonary morbidity among surviving very preterm infants with bronchopulmonary dysplasia (BPD).

RECENT FINDINGS

BPD predisposes very preterm infants to adverse respiratory signs and symptoms, greater respiratory medication use, and more frequent need for rehospitalization throughout early childhood. Reassuringly, studies also indicate that older children and adolescents with BPD experience, on average, similar functional status and quality of life when compared to former very preterm infants without BPD. However, measured deficits in pulmonary function may persist in those with BPD and indicate an increased susceptibility to early-onset chronic obstructive pulmonary disease during adulthood. Moreover, subtle differences in exercise tolerance and activity may put survivors with BPD at further risk of future morbidity in later life.

SUMMARY

Despite advances in neonatal respiratory care, a diagnosis of BPD continues to be associated with significant pulmonary morbidity over the first two decades of life. Long-term longitudinal studies are needed to determine if recent survivors of BPD will also be at increased risk of debilitating pulmonary disease in adulthood.

Diverging effects of premature birth and bronchopulmonary dysplasia on exercise capacity and physical activity - a case control study

Background

Extreme prematurity has been associated with exercise intolerance and reduced physical activity. We hypothesized that children with bronchopulmonary dysplasia (BPD) would be especially affected based on long-term lung function impairments. Therefore, the objective of this study was to compare exercise capacity and habitual physical activity between children born very and extremely preterm with and without BPD and term-born children.

Methods

Twenty-two school-aged children (aged 8 to 12 years) born with a gestational age < 32 weeks and a birthweight < 1500 g (9 with moderate or severe BPD (=BPD), 13 without BPD (=No-BPD)) and 15 healthy term-born children (=CONTROL) were included in the study. Physical activity was measured by accelerometry, lung function by spirometry and exercise capacity by an incremental cardiopulmonary exercise test.

Results

Peak oxygen uptake was reduced in the BPD-group (83 ± 11%predicted) compared to the No-BPD group (91 ± 8%predicted) and the CONTROL group (94 ± 9%predicted). In a general linear model, variance of peak oxygen uptake was significantly explained by BPD status and height but not by prematurity (p < 0.001).

Compared to CONTROL, all children born preterm spent significantly more time in sedentary behaviour (BPD 478 ± 50 min, No-BPD 450 ± 52 min, CONTROL 398 ± 56 min, p < 0.05) and less time in moderate-to-vigorous-physical activity (BPD 13 ± 8 min, No-BPD 16 ± 8 min, CONTROL 33 ± 16 min, p < 0.001). Prematurity but not BPD contributed significantly to explained variance in a general linear model of sedentary behaviour and likewise moderate-to-vigorous-physical activity (p < 0.05 and p < 0.001 respectively).

Conclusion

In our cohort, BPD but not prematurity was associated with a reduced exercise capacity at school-age. However, prematurity regardless of BPD was related to less engagement in physical activity and more time spent in sedentary behaviour. Thus, our findings suggest diverging effects of prematurity and BPD on exercise capacity and physical activity.