Pulmonary outcome in former preterm, very low birth weight children with bronchopulmonary dysplasia: a case-control follow-up at school age

Identification and validation of diagnostic markers and drugs for pediatric bronchopulmonary dysplasia based on integrating bioinformatics and molecular docking analysis

BACKGROUND

BPD is a prevalent chronic lung disease in infancy with lifelong impacts. Its early diagnosis and treatment are hindered by complex pathophysiology and limited mechanistic understanding. This study seeks to establish a foundation for early diagnosis and targeted therapy by identifying diagnostic markers and exploring drug-gene associations.

METHODS

Gene expression data were retrieved from the GEO database. Functional enrichment analyses were conducted on the differentially expressed genes (DEGs). DEGs were used to construct a PPI network. Three algorithms were applied to identify diagnostic markers. Immune cell infiltration was analyzed using the CIBERSORT tool, assessing relationships between immune cells and diagnostic markers. Molecular docking was performed to evaluate interactions between predict candidate drugs and diagnostic markers.

RESULTS

Six hub genes were identified as diagnostic markers. Diagnostic markers showed significant correlations with specific immune cells. Resveratrol and progesterone were found to stably bind to all six diagnostic markers in molecular docking analyses, suggesting therapeutic potential.

CONCLUSION

In conclusion, our results show that IL7R, CXCL10, DEFA4, PRTN3, NCAPG and CCNB1 are BPD diagnostic indicators, and revealing immunological features associated with BPD. The molecular interactions of resveratrol and progesterone with the aforementioned key targets suggest their potential as therapeutic drugs for treating BPD.

[Prognosis of bronchopulmonary dysplasia]

Children with bronchopulmonary dysplasia (BPD) often exhibit severe respiratory problems and significant pulmonary dysfunction during school age and adulthood. Exercise tests show a decline in cardiopulmonary function and physical performance in children with BPD, who also have a higher incidence of pulmonary hypertension. These children generally perform poorly in terms of intelligence, language, and motor development. As they age, the risk of neurodevelopmental disorders increases, and health-related quality of life is also affected. This article reviews the prognosis of the respiratory system, physical capacity, cardiovascular system, nervous system, and health-related quality of life in children with BPD, aiming to improve the management of these patients and enhance their subsequent quality of life.

L-Citrulline in Neonates: From Bench to Bed Side

L-citrulline (L-CIT), a precursor to L-arginine (L-ARG), is a key contributor to the nitric oxide (NO) signaling pathway. Endothelial dysfunction, characterized by deficient nitric oxide synthesis, is implicated in the pathogenesis of various neonatal conditions such as necrotizing enterocolitis (NEC) and bronchopulmonary dysplasia (BPD) associated pulmonary hypertension (PH). This review summarizes the current evidence around the possible role of L-CIT supplementation in the treatment of these conditions. Detoxification of endogenously produced superoxide radicals is inadequate in preterm infants due to immature antioxidants that leads to the production of peroxynitrite, a reactive oxygen-free radical that is cytotoxic and causes damage to organelles and cellular membranes, further disrupting the coupling of endothelial NO synthase enzyme and the generation of high levels of reactive nitrogen and oxygen species. Animal studies in lipopolysaccharide-induced models of chorioamnionitis and hyperoxia- and inflammation-induced BPD-PH in rodent lung models revealed that L-CIT supplementation significantly mitigated structural changes in the pulmonary vasculature, preserved alveolar growth, and increased vascular endothelial growth factor gene expression, highlighting the anti-inflammatory and antioxidant effects of L-CIT supplementation. Similar benefits were noted in newborn piglet models of chronic hypoxia-induced PH and NEC. Pharmacokinetic studies in neonates have shown doses of 100-300 mg/kg/day to be safe and well tolerated. A few studies have shown the beneficial effects of L-CIT supplementation in pulmonary hypertension secondary to congenital heart disease, but evidence of efficacy in the neonatal population is lacking. While L-CIT shows promise in the treatment of various neonatal conditions, adequately powered studies to evaluate the safety and efficacy of L-CIT supplementation post-surgical NEC and BPD ± PH in the extremely preterm population are needed to translate this novel therapy to clinical practice.

A rat model establishment of bronchopulmonary dysplasia-related lung & brain injury within 28 days after birth

PURPOSE

Lung injury associated with bronchopulmonary dysplasia (BPD) and its related neurodevelopmental disorders have garnered increasing attention in the context of premature infants. Establishing a reliable animal model is essential for delving into the underlying mechanisms of these conditions.

METHODS

Newborn rats were randomly assigned to two groups: the hyperoxia-induced BPD group and the normoxia (NO) group. For the BPD group, they were nurtured in a hyperoxic environment with a high oxygen inspired fraction (0.85) from birth until day 14 within 28 days postnatally. In contrast, the NO group consisted of newborn rats that were nurtured in a normoxic environment with a standard oxygen inspired fraction (0.21) for 28 days postnatally. Various pathological sections of both lung and brain tissues were examined. TUNEL staining, immunofluorescence assays, and functional tests were performed, and the results were meticulously analyzed to assess the impact of hyperoxia environments on the developing organs.

RESULTS

In the newborn rats of the BPD group, a significant reduction in alveolar number coupled with enlargement was observed, alongside severe fibrosis, collagen deposition, and constriction of bronchi and vascular lumens. This was accompanied by an accumulation of inflammatory cells and a marked deterioration in lung function compared to the NO group (P < 0.05). Additionally, a decrease in neuronal count, an increase in neuronal apoptosis, proliferation of neuroglia cells, and demyelination were noted, and poorer performance in the Morris water maze test within the BPD group (P < 0.05).

CONCLUSION

The BPD-rats model was established successfully. Lung injury in the BPD group evident across the bronchi to the alveoli and pulmonary vessels, which was associated with deteriorated lung function at postnatal day 14. Concurrently, brain injury extended from the cerebral cortex to the hippocampus, which was associated with impaired performance in orientation navigation and spatial probe tests at postnatal day 28.

Perception of quality of life in school-age children born before 32 weeks of gestational age

Preterm infants with bronchopulmonary dysplasia (BPD) are at increased risk of disruptions in their quality of life (QoL) at school age, often associated with respiratory morbidity and the need for ongoing hospital care. The objective of this study is to assess the impact of BPD on the perceived quality of life in preterm infants at school age. We conducted a prospective observational study of infants born at less than 32 weeks gestation who were admitted to our neonatal unit between January 2012 and December 2014. These children were followed up, and at ages 8 to 10 years, their quality of life was assessed using the Pediatric Quality of Life (PedsQL) questionnaire, with higher scores indicating poorer quality of life. The study included 102 patients with a mean gestational age of 29.42 weeks (SD 1.87) and a mean birth weight of 1221.36 g (SD 347.25), with an average age of 8.59 years (SD 0.90) at the time of the survey. Patients with BPD 2-3 exhibited a significantly poorer perception of "total quality of life" (p = 0.03) and in the "social activities" domain (p = 0.02) compared to those without BPD or with BPD 1, even after adjusting for gestational age in a multivariate model. No significant differences were observed for the "health and activities" domain (p = 0.31), "emotional state" domain (p = 0.58), or "school activities" domain (p = 0.33). Patients who experienced asthma symptoms during follow-up had a poorer perception of total quality of life than those who did not (20.53 (SD 6.19) vs. 11.89 (SD 1.44), p < 0.01). No significant differences were found between patients without a diagnosis of BPD and those with grade 1 BPD. Similarly, no significant differences were observed when comparing patients of less than 28 weeks gestational age and more than 28 weeks of gestational age.

CONCLUSION

In our population of preterm school-aged children with grades 2-3 BPD, worse perceived quality of life was reported compared to those with no BPD or grade 1 BPD. Preterm children who developed asthma symptoms during the follow-up period also reported lower perceived quality of life. No differences in QoL were observed between patients with no BPD and those with grade 1 BPD, or between those born before and after 28 weeks of gestation. These findings highlight the importance of assessing the QoL in preterm patients with BPD, particularly those with grade 2-3 BPD or asthma symptoms, as early assessment can help identify patients who may benefit from targeted interventions to improve quality of life and long-term outcomes.

WHAT IS KNOWN

• Survival rates of extremely preterm infants have increased significantly in recent years, but respiratory morbidity, particularly bronchopulmonary dysplasia, remains a common problem. The impact of BPD on the quality of life of preterm infants, particularly at school age, is still debated. BPD is associated with an increased risk of asthma and abnormal lung function, but its effect on QoL is not fully understood.

WHAT IS NEW

• Preterm infants with grade 2-3 BPD have a significantly worse perception of QoL at school age, especially in the domain of "social activities". This finding emphasises the need for long-term follow-up and possible interventions to improve QoL, especially in terms of social integration. Asthma symptoms during childhood also contribute to poorer QoL perceptions, highlighting the importance of early diagnosis and effective treatment.

Towards a new taxonomy of preterm birth

Disease categories traditionally reflect a historical clustering of clinical phenotypes based on biologic and nonbiologic features. Multiomics approaches have striven to identify signatures to develop individualized categorizations through tests and/or therapies for 'personalized' medicine. Precision health classifies clinical syndromes into endotype clusters based on novel technological advancements, which can reveal insights into the etiologies of phenotypical syndromes. A new taxonomy of preterm birth should be considered in this context, as not all preterm infants of similar gestational ages are the same because most have different biologic vulnerabilities and hence different health trajectories. Even the choice of interventions may affect observed clinical conditions. Thus, a new taxonomy of prematurity would help to advance the field of neonatology, but also obstetrics and perinatology by adopting anticipatory and more targeted approaches to the care of preterm infants with the intent of preventing and treating some of the most common newborn pathologic conditions.

Long-term lung function follow-up of preterm infants less than 32 weeks of gestational age

BACKGROUND

Preterm infants, particularly those with bronchopulmonary dysplasia (BPD), are at risk of lung development problems. Over the last decades, lung protective strategies have been used, decreasing the risk of chronic lung disease.

OBJECTIVE

To evaluate the pulmonary function test (PFT) of preterm infants born after the introduction of lung protective strategies and to assess perinatal determinants of impaired lung function in this population.

METHODS

A prospective, observational, single-center study was conducted in the neonatal unit of a high-complexity hospital. The study included newborns with less than 32 weeks gestational age born between 2012 and 2014, who were followed up until they reach school age. For the main outcome, two groups were stablished: no BPD or grade 1 BPD (no BPD/1) and grade 2 or 3 BPD (BPD 2/3).

RESULTS

Out of 327 patients, 116 were included. BPD was diagnosed in 49.1% (47), with 50.9% (29) classified as grade 1, 35.1% (20) as grade 2, and 14.0% (8) as grade 3. Mean age at PFT was 8.59 years (SD 0.90). Mean FEV1% was 95.36% (SD 13.21) and FEV1 z-score -0.36 (SD 1.12); FVC% 97.53% (SD 12.59) and FVC z-score -0.20 (SD 1.06); FEV1/FVC ratio 85.84% (SD 8.34) and z-score -0.24 (SD 1.34). When comparing patients with no BPD/1 and BPD 2/3, we observed differences in all pulmonary function parameters, which persisted after adjusting for gestational age. No differences in PFT were observed between patients without BPD and those with grade 1 BPD. Most patients (76.7%, 89) had normal spirometry pattern, with obstructive pattern observed in 12.9% (15), restrictive pattern in 9.5% (11), and mixed pattern in 0.9% (1) of patients.

CONCLUSION

Preterm infants with BPD 2/3 showed a decrease in all pulmonary function parameters compared to preterm infants with no BPD/1; an effect that was independent of gestational age. Among patients with BPD who had an altered PFT pattern, the most common pattern was obstructive, followed by restrictive and then, mixed.

[Measurement of intrinsic positive end-expiratory pressure and clinical outcomes of infants with severe bronchopulmonary dysplasia]

OBJECTIVES

To investigate the levels of intrinsic positive end-expiratory pressure (PEEPi) in infants with severe bronchopulmonary dysplasia (sBPD) and the relationship between different levels of PEEPi and clinical outcomes.

METHODS

A retrospective analysis was conducted on the clinical data of 12 sBPD infants who underwent PEEPi measurement and were hospitalized at Guangzhou Women and Children's Medical Center from January 2022 to June 2023. The clinical manifestations and outcomes at discharge were compared between infants with very high PEEPi (≥10 cmH2O) and those with lower PEEPi (<10 cmH2O).

RESULTS

PEEPi measurements were taken in 12 sBPD infants between gestational age 31+3 and 67+2 weeks postmenstrual age, with the lowest PEEPi measured at 0.9 cmH2O and the highest at 19.6 cmH2O; 50% (6/12) of the infants had PEEPi ≥10 cmH2O. All infants with very high PEEPi exhibited ineffective triggering and patient-ventilator asynchrony. Among them, 5 infants could not be weaned off invasive ventilation, resulting in 4 deaths and 1 infant being discharged with a tracheostomy and ventilator support. In contrast, among the infants with PEEPi <10 cmH2O, only 1 infant died, while the others were successfully extubated and discharged.

CONCLUSIONS

Infants with sBPD may have elevated PEEPi levels, and very high PEEPi may be associated with adverse outcomes in these patients.

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.

Repeated intravenous doses of human umbilical cord-derived mesenchymal stromal cells for bronchopulmonary dysplasia: results of a phase 1 clinical trial with 2-year follow-up

BACKGROUND

Currently, there is a lack of effective treatments or preventive strategies for bronchopulmonary dysplasia (BPD). Pre-clinical studies with mesenchymal stromal cells (MSCs) have yielded encouraging results. The safety of administering repeated intravenous doses of umbilical cord tissue-derived mesenchymal stromal cells (UC-MSCs) has not yet been tested in extremely-low-gestational-age newborns (ELGANs).

AIMS

to test the safety and feasibility of administering three sequential intravenous doses of UC-MSCs every 7 days to ELGANs at risk of developing BPD.

METHODS

In this phase 1 clinical trial, we recruited ELGANs (birth weight ≤1250 g and ≤28 weeks in gestational age [GA]) who were on invasive mechanical ventilation (IMV) with FiO2 ≥ 0.3 at postnatal days 7-14. Three doses of 5 × 106/kg of UC-MSCs were intravenously administered at weekly intervals. Adverse effects and prematurity-related morbidities were recorded.

RESULTS

From April 2019 to July 2020, 10 patients were recruited with a mean GA of 25.2 ± 0.8 weeks and a mean birth weight of 659.8 ± 153.8 g. All patients received three intravenous UC-MSC doses. The first dose was administered at a mean of 16.6 ± 2.9 postnatal days. All patients were diagnosed with BPD. All patients were discharged from the hospital. No deaths or any serious adverse events related to the infusion of UC-MSCs were observed during administration, hospital stays or at 2-year follow-up.

CONCLUSIONS

The administration of repeated intravenous infusion of UC-MSCs in ELGANs at a high risk of developing BPD was feasible and safe in the short- and mid-term follow-up.

Early metabolic markers as predictors of respiratory complications in preterm infants with bronchopulmonary dysplasia

BACKGROUND

Bronchopulmonary dysplasia (BPD), a common complication of premature birth, exerts considerable impact on the respiratory health of infants. This study aimed to identify the role of plasma metabolites in predicting respiratory outcomes in BPD-afflicted infants.

METHODS

This was a case-control study including 15 BPD premature infants and 15 gestational age and birth weight matched no-BPD preterm infants. Plasma samples, obtained at 36 weeks postmenstrual age (PMA), were subjected to a comprehensive analysis of over 300 metabolites using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The respiratory outcomes of the infants were collected with the first 2 years of corrected postnatal age.

RESULTS

The analysis revealed a significant upregulation of urea and downregulation of nine metabolites in BPD infants, including oxalacetic acid, cis-aconitic acid, itaconic acid, betaine, L-asparagine, L-alanine, picolinic acid, inositol, and purine (p < 0.05). These metabolites primarily pertained to the citrate cycle (TCA cycle), glyoxylate and dicarboxylate metabolism, and alanine, aspartate, and glutamate metabolism. Furthermore, seven metabolites demonstrated substantial predictive capacity for respiratory readmissions within the first two years of corrected postnatal age, achieving an area under curve (AUC) exceeding or equal to 0.8. These included chenodeoxycholic acid, dehydrolithocholic acid, glucaric acid, D-glucuronic acid, gamma-glutamylvaline, mevalonic acid, and 3-ureidopropionic acid.

CONCLUSIONS

This study identified ten distinct plasma metabolites at 36 weeks PMA that differentiate BPD infants from their non-BPD counterparts, implicating three major metabolic pathways. Additionally, seven metabolites showed strong predictive value for heightened risk of respiratory readmission within two years, underscoring their potential utility in clinical prognostication and management strategies for BPD.

TGF-β controls alveolar type 1 epithelial cell plasticity and alveolar matrisome gene transcription in mice

Premature birth disrupts normal lung development and places infants at risk for bronchopulmonary dysplasia (BPD), a disease disrupting lung health throughout the life of an individual and that is increasing in incidence. The TGF-β superfamily has been implicated in BPD pathogenesis, however, what cell lineage it impacts remains unclear. We show that TGFbr2 is critical for alveolar epithelial (AT1) cell fate maintenance and function. Loss of TGFbr2 in AT1 cells during late lung development leads to AT1-AT2 cell reprogramming and altered pulmonary architecture, which persists into adulthood. Restriction of fetal lung stretch and associated AT1 cell spreading through a model of oligohydramnios enhances AT1-AT2 reprogramming. Transcriptomic and proteomic analyses reveal the necessity of TGFbr2 expression in AT1 cells for extracellular matrix production. Moreover, TGF-β signaling regulates integrin transcription to alter AT1 cell morphology, which further impacts ECM expression through changes in mechanotransduction. These data reveal the cell intrinsic necessity of TGF-β signaling in maintaining AT1 cell fate and reveal this cell lineage as a major orchestrator of the alveolar matrisome.

Five-year follow-up of phase II trial of stromal cells for bronchopulmonary dysplasia

BACKGROUND

We previously performed a phase II randomised double-blind clinical trial of mesenchymal stromal cell (MSCs) transplantation to prevent bronchopulmonary dysplasia in extremely premature infants. Subsequently, we followed the infants enrolled in this clinical trial to determine the safety and effectiveness of MSCs against bronchopulmonary dysplasia at 5-year follow-up.

METHODS

We evaluated infants at 5 years of age receiving placebo or MSCs in a prospective follow-up study.

RESULTS

In terms of the primary end point of composite respiratory morbidities, including respiratory problem-related readmission, emergency department visits or oxygen therapy, the MSC group had a rate of 60.7% for composite morbidities, while the control group showed a tendency of higher rate of 83.9% for the same outcomes without statistical significance. In terms of the secondary outcomes, the MSC group infants showed a tendency of being less likely to visit emergency department (control 67.7% vs MSC 35.7%) and to receive oxygen therapy (control 29.0% vs MSC 3.6%). No difference was observed in the incidence of respiratory problem-related hospital readmission or wheezing episodes between the groups.

CONCLUSION

Intratracheally instilled MSCs showed the possibility of potential to decrease respiratory symptom-related emergency department visits and oxygen therapy episodes in infants born extremely preterm during the 5 years after a phase II randomised controlled, double-blind trial of MSCs transplantation for bronchopulmonary dysplasia. This small size study suggests preliminary insights that can be further tested using larger sample sizes.

TRIAL REGISTRATION NUMBER

NCT01897987.

Mesenchymal stromal/stem cells and bronchopulmonary dysplasia

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

Outpatient management of established bronchopulmonary dysplasia: An update

As the incidence of infants with bronchopulmonary dyspasia (BPD) has continued to rise, so has their rate of survival. Their medical management is often complex and requires the use of numerous therapies such as steroids, bronchodilators, diuretics and modalities to deliver supplemental oxygen and positive pressure. It also requires multi-disciplinary care to ensure adequate growth and to optimize neurodevelopmental outcomes. This review aims to discuss the most widely used therapies in the treatment of patients with established BPD. The focus will be on ongoing outpatient (post-neonatal intensive care) management of children with BPD. Since many of the mentioned therapies lack solid evidence to support their use, more high quality research, such as randomized controlled trials, is needed to assess their effectiveness using defined outcomes.

Lung biopsy in infants with severe bronchopulmonary dysplasia

INTRODUCTION

Lung biopsy is infrequently performed in the population of infants with severe bronchopulmonary dysplasia (BPD). Yet, its presentation may overlap with other infant diffuse lung diseases, including those within the spectrum of childhood interstitial lung diseases (chILD). Lung biopsy might differentiate between these entities or identify those with an extremely poor prognosis. Both might alter the clinical management of some infants diagnosed with BPD.

METHODS

In this tertiary referral center, we drew on a retrospective cohort of 308 preterm infants with severe BPD. Of these, nine underwent lung biopsy between 2012 and 2017. We aimed to assess the indication for lung biopsy, the prior clinical history, safety of the procedure, and describe the biopsy findings. Finally, we considered management decisions in relation to the biopsy results in these patients.

RESULTS

All nine infants undergoing biopsy survived the procedure. The mean gestational age and birth weight of the nine patients were 30 ± 3 (range 27-34) weeks and 1421 ± 571 (range 611-2140) grams. All infants received serial echocardiograms to assess pulmonary hypertension, genetic testing, and computed tomography angiography (CTA) before biopsy. In all nine patients moderate to severe alveolar simplification was present and eight had some degree of pulmonary interstitial glycogenosis (PIG) ranging from focal to diffuse. Following biopsy, two infants with PIG received high dose systemic steroids and two separate infants had care redirected.

CONCLUSION

In our cohort, lung biopsy was safe and well tolerated. Findings from lung biopsy may aid decision making in selected patients as a part of a step-wise diagnostic algorithm.

Risk of asthma in preterm infants with bronchopulmonary dysplasia: a systematic review and meta-analysis

BACKGROUND

This study aimed to systematically review and meta-analyze the available literature on the association between preterm infant bronchopulmonary dysplasia (BPD) and pre-adulthood asthma.

METHODS

Studies examining the association between BPD and asthma in children and adolescents were systematically reviewed, and a meta-analysis was conducted. We searched Scopus, Embase, Web of Science, PubMed, and Cochrane Library from the database inception to March 26, 2022. The pooled odds ratio (OR) estimate was used in our meta-analysis to calculate the correlation between BPD and the probability of developing asthma before adulthood. Stata 12.0 was used to conduct the statistical analysis.

RESULTS

The correlation between asthma and BPD in preterm newborns was examined in nine studies. We used a random effect model to pool the OR estimate. Our results indicated a marked increase in the risk of subsequent asthma in preterm infants with BPD [OR = 1.73, 95% confidence interval (CI) = 1.43-2.09]. Moreover, there was no obvious heterogeneity across the studies (P = 0.617, I2 = 0%). The pooled OR remained stable and ranged from 1.65 (95% CI = 1.35-2.01) to 1.78 (95% CI = 1.43-2.21). Regarding publication bias, the funnel plot for asthma risk did not reveal any noticeable asymmetry. We further performed Begg's and Egger's tests to quantitatively evaluate publication bias. There was no evidence of a publication bias for asthma risk (P > |Z| = 0.602 for Begg's test, and P > |t| = 0.991 for Egger's test).

CONCLUSIONS

Our findings indicate that preterm infants with BPD have a much higher risk of developing asthma in the future (OR = 1.73, 95% CI = 1.43-2.09). Preterm infants with BPD may benefit from long-term follow-up.

TGFβ controls alveolar type 1 epithelial cell plasticity and alveolar matrisome gene transcription

Premature birth disrupts normal lung development and places infants at risk for bronchopulmonary dysplasia (BPD), a disease increasing in incidence which disrupts lung health throughout the lifespan. The TGFβ superfamily has been implicated in BPD pathogenesis, however, what cell lineage it impacts remains unclear. We show that Tgfbr2 is critical for AT1 cell fate maintenance and function. Loss of Tgfbr2 in AT1 cells during late lung development leads to AT1-AT2 cell reprogramming and altered pulmonary architecture, which persists into adulthood. Restriction of fetal lung stretch and associated AT1 cell spreading through a model of oligohydramnios enhances AT1-AT2 reprogramming. Transcriptomic and proteomic analysis reveal the necessity of Tgfbr2 expression in AT1 cells for extracellular matrix production. Moreover, TGFβ signaling regulates integrin transcription to alter AT1 cell morphology, which further impacts ECM expression through changes in mechanotransduction. These data reveal the cell intrinsic necessity of TGFβ signaling in maintaining AT1 cell fate and reveal this cell lineage as a major orchestrator of the alveolar matrisome.

Harnessing the therapeutic potential of the stem cell secretome in neonatal diseases

Preterm birth and intrapartum related complications account for a substantial amount of mortality and morbidity in the neonatal period despite significant advancements in neonatal-perinatal care. Currently, there is a noticeable lack of curative or preventative therapies available for any of the most common complications of prematurity including bronchopulmonary dysplasia, necrotizing enterocolitis, intraventricular hemorrhage, periventricular leukomalacia and retinopathy of prematurity or hypoxic-ischemic encephalopathy, the main cause of perinatal brain injury in term infants. Mesenchymal stem/stromal cell-derived therapy has been an active area of investigation for the past decade and has demonstrated encouraging results in multiple experimental models of neonatal disease. It is now widely acknowledged that mesenchymal stem/stromal cells exert their therapeutic effects via their secretome, with the principal vector identified as extracellular vesicles. This review will focus on summarizing the current literature and investigations on mesenchymal stem/stromal cell-derived extracellular vesicles as a treatment for neonatal diseases and examine the considerations to their application in the clinical setting.

Maternal and neonatal risk factors of asthma in children: Nationwide population based study

BACKGROUND

Small population group-based cohorts have found that perinatal factors may contribute to the development of asthma in children. We aimed to investigate maternal and neonatal risk factors for the asthma phenotypes using two databases from the Taiwan's Maternal and Child Health Database (TMCHD) and the National Health Insurance Research Database (NHIRD).

METHODS

Perinatal data was obtained from 2004 to 2008 in the TMCHD and linked the NHIRD to obtain relevant medical information regarding maternal and neonatal risk factors of three asthma phenotypes which were identified as transient early asthma, persistent asthma, and late-onset asthma. A multivariate logistic regression analysis was conducted to adjust for covariates.

RESULTS

The percentage of non-asthmatic patients was 77.02% and asthmatic (transient early asthma, late onset asthma, and persistent asthma) patients were 8.96%, 11.64%, and 2.42%, respectively. Maternal risk factors-including Cesarean section, maternal asthma, maternal allergic rhinitis (AR), and premature rupture of membranes-and neonatal risk factors, such as male gender, gestational age 29-37 weeks, ventilator use, antibiotics use, AR, and atopic dermatitis, were associated with the development of these three asthma phenotypes. Twins and a gestational age of 28 weeks or less premature were associated with the development of transient early asthma and persistent asthma, but not late onset asthma. Triplets and above were associated with the development of transient early asthma, but not late onset or persistent asthma.

CONCLUSION

Various asthma phenotypes have different risk factors; therefore, their distinct risk factors should be identified in order to early diagnosis and treatment.

Early Origins of Chronic Obstructive Pulmonary Disease: Prenatal and Early Life Risk Factors

The main risk factor for chronic obstructive pulmonary disease (COPD) is active smoking. However, a considerable amount of people with COPD never smoked, and increasing evidence suggests that adult lung disease can have its origins in prenatal and early life. This article reviews some of the factors that can potentially affect lung development and lung function trajectories throughout the lifespan from genetics and prematurity to respiratory tract infections and childhood asthma. Maternal smoking and air pollution exposure were also analyzed among the environmental factors. The adoption of preventive strategies to avoid these risk factors since the prenatal period may be crucial to prevent, delay the onset or modify the progression of COPD lung disease throughout life.

Identification of Premature Infants at High Risk of Late Respiratory Diseases: A Retrospective Cohort Study

Aim

To identify infants with very low birth weight at risk of late respiratory diseases after discharge.

Methods

This retrospective longitudinal study included 388 preterm infants with gestational age of < 32 weeks and birth weight of < 1,500 g and evaluated perinatal information, assessments performed while in the neonatal intensive care unit, and longitudinal follow-up via questionnaire until the corrected gestational age of 18-24 months.

Results

The mean birth weight and gestational age were 1,191.2 ± 191.8 g and 29.1 ± 1.4 weeks, respectively. Sixty-four (16.5%) infants developed late respiratory diseases after discharge to the corrected gestational age of 18-24 months. Univariate analyses showed that gestational age, birth weight, respiratory support, oxygen use, bronchopulmonary dysplasia diagnosed at 36 weeks' postmenstrual age and length of hospital stay were associated with late respiratory diseases. After adjusting for covariates, respiratory support was significantly associated with serious respiratory morbidities to 18-24 months corrected gestational age. With each day of respiratory support, the odds of late respiratory diseases increased by 1.033-fold.

Conclusion

Respiratory support was associated with increased odds of developing late respiratory diseases during early childhood, which may be an early predictor to late respiratory morbidities. Thus, it is imperative to identify a safe and effective strategy to prevent chronic dependency on respiratory support.

Comparison of respiratory distress syndrome amongst preterm twins (28-34 Weeks) born within and after two weeks of completion of single antenatal corticosteroid course: A bidirectional cohort study

BACKGROUND

The literature on neonatal outcomes in preterm twins delivered before 34 weeks but within and after 14 days of a single initial steroid course is limited.

MATERIAL AND METHODS

This bidirectional (226 prospective and 42 retrospectives) cohort study was performed at a tertiary care teaching hospital in South India. We compared the respiratory distress syndrome and neonatal death amongst preterm twins from 28 to 34 weeks born < 14 days (Group A, n=268) and after 14 days (Group B, n=268) of completion of a single course of antenatal steroids. We used multivariable regression analysis (log-binomial model) to adjust for confounding variables. We generated a propensity-matched score with probit regression to analyse outcomes (respiratory distress and neonatal deaths).

RESULTS

The two groups had significant differences in the distribution of birthweight, gestation period and mode of delivery. On adjusted analysis, the period of gestation below 33 weeks and weight below 1.5 kg had the maximum influence on respiratory and other morbidities, and weight less than 1 kg on neonatal death. [adjusted relative risk (ARR) 26.06, (95%CI=2.37-285.5), p=0.008]. On propensity scoring after matching all these variables, we found an [ARR of 2.0 (95% CI: 1.03-3.88), P=0.017] for neonatal death after 14 days of steroid injection. The ARR for respiratory distress syndrome was 1.13 in those born after 14 days of steroids, though it did not reach statistical significance.

CONCLUSION

On propensity scoring, the steroid-delivery interval more than 14 days was associated with a significantly increased risk (ARR of 2) of neonatal death.

Novel Ventilation Strategies to Reduce Adverse Pulmonary Outcomes

Extremely preterm infants who must suddenly support their own gas exchange with lungs that are incompletely developed and lacking adequate amount of surfactant and antioxidant defenses are susceptible to lung injury. The decades-long quest to prevent bronchopulmonary dysplasia has had limited success, in part because of increasing survival of more immature infants. The process must begin in the delivery room with gentle assistance in establishing and maintaining adequate lung aeration, followed by noninvasive support and less invasive surfactant administration. Various modalities of invasive and noninvasive support have been used with varying degree of effect and are reviewed in this article.

Effectiveness and safety of early combined utilization of budesonide and surfactant by airway for bronchopulmonary dysplasia prevention in premature infants with RDS: A meta-analysis

OBJECTIVE

To address the effectiveness and safety of early airway combined utilization of budesonide and surfactant for bronchopulmonary dysplasia (BPD) prevention in premature infants with respiratory distress syndrome (RDS).

METHODS

Literature retrieval was carried out in the PubMed, Web of Science, EMBASE, Cochrane Library, Wanfang, CQ VIP, and China National Knowledge Infrastructure databases, searching from the inception to September 2021. Stata 16.0 software was used for statistical analysis.

RESULTS

This meta-analysis suggested that early combined utilization of budesonide and surfactant by airway have a superiority on BPD incidence (risk ratio [RR] = 0.62; 95% confidence interval [CI]: 0.54-0.71, p < 0.001], mortality (RR = 0.64; 95%CI: 0.45-0.92, p = 0.016), the composite outcome of BPD or mortality (RR = 0.58; 95%CI: 0.50-0.68, p < 0.001), the additional doses of surfactant (RR = 0.53; 95%CI: 0.44-0.63, p < 0.001), the duration of assisted ventilation (standard mean difference [SMD] = -1.14; 95%CI: -1.58 to -0.70, p < 0.001), duration of invasive ventilation(SMD = -1.77; 95% CI: -2.61 to -0.93, p < 0.001), and hospital stays (SMD = -1.11; 95% CI: -1.73 to -0.49, p = 0.001) in preterm infants with RDS. And these benefits were not associated with increased adverse outcomes. Furthermore, a decreased incidence of patent ducts arterious (PDA) (RR = 0.79; 95% CI: 0.65 to 0.97, p = 0.028) was found in premature infants treated with budesonide and surfactant. Subgroup analysis based on budesonide delivery methods (inhalation or intratracheal instillation) indicated that the decrease of mortality (RR = 0.63; 95% CI: 0.43-0.93, p = 0.019), duration of assisted ventilation (SMD = -0.95; 95% CI: -1.30 to -0.61, p < 0.001), hospital stays (SMD = -1.23; 95% CI: -2.05 to -0.41, p = 0.003) and PDA incidence (RR = 0.80; 95% CI: 0.65 to 0.99, p = 0.044) were mainly in budesonide intratracheal instillation subgroup, rather than in budesonide inhalation subgroup.

CONCLUSIONS

This meta-analysis suggested that early combined utilization of budesonide and surfactant by airway might be an effective and safe clinical practice for BPD prevention in premature infants with RDS, especially when budesonide was delivered by intratracheal instillation. However, many of the included studies were small and were from Asian origin. More well-designed randomized controlled trials with larger sample sizes and longer follow-up from all over the world ought to be conducted in the future.

Physiological aspects of cardiopulmonary dysanapsis on exercise in adults born preterm

Progressive improvements in perinatal care and respiratory management of preterm infants have resulted in increased survival of newborns of extremely low gestational age over the past few decades. However, the incidence of bronchopulmonary dysplasia, the chronic lung disease after preterm birth, has not changed. Studies of the long-term follow-up of adults born preterm have shown persistent abnormalities of respiratory, cardiovascular and cardiopulmonary function, possibly leading to a lower exercise capacity. The underlying causes of these abnormalities are incompletely known, but we hypothesize that dysanapsis, i.e. discordant growth and development, in the respiratory and cardiovascular systems is a central structural feature that leads to a lower exercise capacity in young adults born preterm than those born at term. We discuss how the hypothesized system dysanapsis underscores the observed respiratory, cardiovascular and cardiopulmonary limitations. Specifically, adults born preterm have: (1) normal lung volumes but smaller airways, which causes expiratory airflow limitation and abnormal respiratory mechanics but without impacts on pulmonary gas exchange efficiency; (2) normal total cardiac size but smaller cardiac chambers; and (3) in some cases, evidence of pulmonary hypertension, particularly during exercise, suggesting a reduced pulmonary vascular capacity despite reduced cardiac output. We speculate that these underlying developmental abnormalities may accelerate the normal age-associated decline in exercise capacity, via an accelerated decline in respiratory, cardiovascular and cardiopulmonary function. Finally, we suggest areas of future research, especially the need for longitudinal and interventional studies from infancy into adulthood to better understand how preterm birth alters exercise capacity across the lifespan.

Prediction Models for Bronchopulmonary Dysplasia in Preterm Infants: A Systematic Review

OBJECTIVE

To provide an overview and critical appraisal of prediction models for bronchopulmonary dysplasia (BPD) in preterm infants.

METHODS

We searched PubMed, Embase, and the Cochrane Library to identify relevant studies (up to November 2021). We included studies that reported prediction model development and/or validation of BPD in preterm infants born at ≤32 weeks and/or ≤1,500 g birth weight. We extracted the data independently based on the CHecklist for critical Appraisal and data extraction for systematic Reviews of prediction Modelling Studies (CHARMS). We assessed risk of bias and applicability independently using the Prediction model Risk Of Bias ASsessment Tool (PROBAST).

RESULTS

Twenty-one prediction models from 13 studies reporting on model development and 21 models from 10 studies reporting on external validation were included. Oxygen dependency at 36 weeks' postmenstrual age was the most frequently reported outcome in both development studies (71%) and validation studies (81%). The most frequently used predictors in the models were birth weight (67%), gestational age (62%), and sex (52%). Nearly all included studies had high risk of bias, most often due to inadequate analysis. Small sample sizes and insufficient event patients were common in both study types. Missing data were often not reported or were discarded. Most studies reported on the models' discrimination, while calibration was seldom assessed (development, 19%; validation, 10%). Internal validation was lacking in 69% of development studies.

CONCLUSION

The included studies had many methodological shortcomings. Future work should focus on following the recommended approaches for developing and validating BPD prediction models.

Chronic respiratory failure in bronchopulmonary dysplasia

Although survival has improved dramatically for extremely preterm infants, those with the most severe forms of bronchopulmonary dysplasia (BPD) fail to improve in the neonatal period and go on to develop chronic respiratory failure. When careful weaning of respiratory support is not tolerated, the difficult decision of whether or not to pursue chronic ventilation via tracheostomy must be made. This requires shared decision-making with an interdisciplinary medical team and the child's family. Although they suffer from increased morbidity and mortality, the majority of these children will survive to tolerate ventilator liberation and tracheostomy decannulation. Care coordination for the technology-dependent preterm infant is complex, but there is a growing consensus that chronic ventilation can best support neurodevelopmental progress and improve long-term outcomes.

Lung growth and pulmonary function after prematurity and bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) still carries a heavy burden of morbidity and mortality in survivors of extreme prematurity. The disease is characterized by simplification of the alveolar structure, involving a smaller number of enlarged alveoli due to decreased septation and a dysmorphic pulmonary microvessel growth. These changes lead to persistent abnormalities mainly affecting the smaller airways, lung parenchyma, and pulmonary vasculature, which can be assessed with lung function tests and imaging techniques. Several longitudinal lung function studies have demonstrated that most preterm-born subjects with BPD embark on a low lung function trajectory, never achieving their full airway growth potential. They are consequently at higher risk of developing a chronic obstructive pulmonary disease-like phenotype later in life. Studies based on computer tomography and magnetic resonance imaging, have also shown that in these patients there is a persistence of lung abnormalities like emphysematous areas, bronchial wall thickening, interstitial opacities, and mosaic lung attenuation also in adult age. This review aims to outline the current knowledge of pulmonary and vascular growth in survivors of BPD and the evidence of their lung function and imaging up to adulthood.

Design-Based Stereology of the Lung in the Hyperoxic Preterm Rabbit Model of Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a complex condition frequently occurring in preterm newborns, and different animal models are currently used to mimic the pathophysiology of BPD. The comparability of animal models depends on the availability of quantitative data obtained by minimally biased methods. Therefore, the aim of this study was to provide the first design-based stereological analysis of the lungs in the hyperoxia-based model of BPD in the preterm rabbit. Rabbit pups were obtained on gestation day 28 (three days before term) by cesarean section and exposed to normoxic (21% O2, n = 8) or hyperoxic (95% O2, n = 8) conditions. After seven days of exposure, lung function testing was performed, and lungs were taken for stereological analysis. In addition, the ratio between pulmonary arterial acceleration and ejection time (PAAT/PAET) was measured. Inspiratory capacity and static compliance were reduced whereas tissue elastance and resistance were increased in hyperoxic animals compared with normoxic controls. Hyperoxic animals showed signs of pulmonary hypertension indicated by the decreased PAAT/PAET ratio. In hyperoxic animals, the number of alveoli and the alveolar surface area were reduced by one-third or by approximately 50% of control values, respectively. However, neither the mean linear intercept length nor the mean alveolar volume was significantly different between both groups. Hyperoxic pups had thickened alveolar septa and intra-alveolar accumulation of edema fluid and inflammatory cells. Nonparenchymal blood vessels had thickened walls, enlarged perivascular space, and smaller lumen in hyperoxic rabbits in comparison with normoxic ones. In conclusion, the findings are in line with the pathological features of human BPD. The stereological data may serve as a reference to compare this model with BPD models in other species or future therapeutic interventions.

Predictive Ability of the New Bronchopulmonary Dysplasia Definition on Pulmonary Outcomes at 20 to 24 months' Corrected Age of Preterm Infants

OBJECTIVE

 This study aimed to determine the predictive abilities of the National Institute of Child Health and Human Development (NICHD) 2018 definition of bronchopulmonary dysplasia (BPD) on mortality and pulmonary outcomes of preterm infants at 20 to 24 months' corrected age and compare them with the National Institutes of Health (NIH) 2001 definition.

STUDY DESIGN

 A retrospective cohort study was conducted in a level III neonatal intensive care unit (NICU) in Bangkok, Thailand. Data from 502 infants less than 32 weeks of gestation born between 2011 and 2017 were reviewed. Follow-up data were available in 460 infants (91.6%). BPD severity was graded according to the NICHD 2018 and the NIH 2001 definitions. Infants' mortality and pulmonary outcomes were compared between these two definitions.

RESULTS

 The prevalence of BPD by the NIH 2001 and NICHD 2018 definition were 52.4 and 23.9%, respectively. Using the NIH 2001 definition, the severity of BPD could not be classified in 4.2% of the infants. Progressive severity of BPD by the NICHD 2018 definition was associated with higher incidence of pulmonary morbidities. By using area under the curve (AUC), the accuracy of NICHD 2018 definition in predicting death due to respiratory diseases and home oxygen therapy were significantly higher than those using NIH 2001 definition (0.884 vs. 0.740 [p <0.001] and 0.893 vs. 0.746 [p <0.001], respectively).

CONCLUSION

 The NICHD 2018 definition of BPD categorized fewer preterm infants with BPD in our cohort of preterm infants. This current definition has better predictive ability on mortality and pulmonary morbidities than the NIH 2001 definition.

KEY POINTS

· The NICHD 2018 BPD definition has not been validated for predicting long-term pulmonary outcomes.. · The NICHD 2018 definition categorized fewer preterm infants with BPD in our cohort of preterm.. · The NICHD 2018 definition adequately predicted mortality and morbidities of preterm infants..

Lung function between 8 and 15 years of age in very preterm infants with fetal growth restriction

BACKGROUND

The impact of intrauterine growth restriction (IUGR) on lung function in very preterm children is largely unknown as current evidence is mainly based on studies in children born small for gestational age but not necessarily with IUGR.

METHODS

Spirometry, transfer factor of the lung for carbon monoxide (TLco), and lung clearance index (LCI) were cross-sectionally evaluated at 8.0-15.0 years of age in children born <32 weeks of gestation with IUGR (n = 28) and without IUGR (n = 67). Controls born at term (n = 67) were also included.

RESULTS

Very preterm children with IUGR had lower mean forced expired volume in the first second (FEV₁) z-score than those with normal fetal growth (∆ -0.66, 95% confidence interval (CI) -1.12, -0.19), but not significant differences in LCI (∆ +0.24, 95% CI -0.09, 0.56) and TLco z-score (∆ -0.11, 95% CI -0.44, 0.23). The frequency of bronchopulmonary dysplasia (BPD) in the two groups was, respectively, 43% and 10% (P = 0.003). IUGR was negatively associated with FEV₁ (B = -0.66; P = 0.004), but the association lost significance (P = 0.05) when adjusting for BPD.

CONCLUSIONS

IUGR has an impact on conducting airways function of very preterm children at school age, with part of this effect being mediated by BPD. Ventilation inhomogeneity and diffusing capacity, instead, were not affected.

IMPACT

IUGR does not necessarily imply a low birthweight for gestational age (and vice versa). While a low birthweight is associated with worse respiratory outcomes, the impact of IUGR on lung function in premature children is largely unknown. IUGR affects conducting airways function in school-age children born <32 weeks with IUGR, but not ventilation inhomogeneity and diffusing capacity. The impact of IUGR on FEV₁ seems mainly related to the higher risk of BPD in this group.

Clinical Characteristics and Outcomes Until 2 Years of Age in Preterm Infants With Typical Chest Imaging Findings of Bronchopulmonary Dysplasia: A Propensity Score Analysis

Objective: The goal of the current study was to assess the associations of typical chest imaging findings of bronchopulmonary dysplasia (BPD) in preterm infants with clinical characteristics and outcomes until 2 years of age. Method: This retrospective cohort study enrolled 256 preterm infants with BPD who were admitted between 2014 and 2018. A propensity score analysis was used to adjust for confounding factors. The primary outcomes were the severity of BPD, home oxygen therapy (HOT) at discharge and mortality between 28 days after birth and 2 years of age. A multivariate logistic regression analysis was performed to identify related variables of mortality. Results: Seventy-eight patients with typical chest imaging findings were enrolled, of which 50 (64.1%) were first found by CXR, while 28 (35.9%) were first found by CT. In addition, 85.9% (67/78) were discovered before 36 weeks postmenstrual age (PMA) (gestational age [GA] < 32 weeks) or before 56 days after birth (GA > 32 weeks). After propensity score matching, the matched groups consisted of 58 pairs of patients. Those with typical imaging findings had a remarkably higher mortality rate (29.3 vs. 12.1%, p = 0.022, OR 3.021), higher proportion of severe BPD (32.8 vs. 12.1%, p = 0.003, OR 4.669) and higher rate of HOT at discharge (74.1 vs. 46.6%, p = 0.002, OR 3.291) than those without typical imaging findings. The multivariate logistic regression analysis showed that typical imaging findings ≤ 7 days and typical typical imaging findings >7 days were independent risk factors for mortality in preterm infants with BPD (OR 7.794, p = 0.004; OR 4.533, p = 0.001). Conclusions: More attention should be given to chest imaging findings of BPD, especially in the early stage (within 7 days). Early recognition of the development of BPD helps early individualized treatment of BPD. Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT04163822.

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.

Predictors of pulmonary function at 6 years of age in infants with bronchopulmonary dysplasia

RATIONALE

Bronchopulmonary dysplasia (BPD) is a major complication of premature birth and the most common cause of chronic lung disease in infancy. Previous studies have shown that children with a history of BPD have impaired lung function in childhood compared to their term counterparts. However, little is known about potential modifiable factors that alter lung function trajectories and subsequent respiratory morbidity in this population.

OBJECTIVES

To identify potential modifiable risk factors for the development of impaired lung function in patients with a history of prematurity and bronchopulmonary dysplasia.

METHODS

Growth parameters (birth, 2 years old, 6 years old) and pulmonary function testing (6 years old) were retrospectively reviewed for subjects (n = 598) recruited from an outpatient BPD clinic who were born ≤36 weeks gestation and were ≥5 years of age.

RESULTS

Of the 598 recruited subjects, 88 (14.7%) performed adequate pulmonary function testing at approximately 6 years of age. The mean forced expiratory volume in 1 s global lung initiative (GLI) Z-score was -1.31 with lower values associated with Nissen fundoplication. The mean forced vital capacity GLI Z-score was -0.72 with lower values associated with higher amounts of oxygen required at time of initial hospital discharge and Nissen fundoplication.

CONCLUSION

Our study found that children with BPD have lower predicted lung function values. Although growth parameters at age 2 and 6 years did not correlate with lung function values at 6 years of age; use and greater requirement for supplemental oxygen and the presence of a Nissen fundoplication at discharge were associated with lower lung function. Prospective studies should focus on identifying modifiable risk factors that could minimize the impact of BPD on later lung function.

Respiratory effects of prolonged prednisolone use in infants with evolving and established Bronchopulmonary dysplasia

BACKGROUND

Current literature focuses on systemic corticosteroids for prevention of bronchopulmonary dysplasia (BPD) in preterm infants with limited data on use for pulmonary disease after the first month of life. Prednisolone may be a reasonable option for late treatment given its desirable pharmacologic properties and use in other pediatric disease states.

AIMS

To characterize a premature population that received an extended prednisolone course and determine the effect on respiratory and anthropometric outcomes over time.

STUDY DESIGN

Single-center, retrospective study.

SUBJECTS

Preterm infants who received ≥30 days of prednisolone or methylprednisolone for treatment of respiratory complications following preterm birth.

OUTCOMES MEASURES

Assessment of pulmonary severity score (PSS), weight, length, and occipital frontal circumference weekly during the first 4 weeks of prednisolone and after discontinuation.

RESULTS

Thirty-four infants with a mean gestational age of 26.5 ± 2.5 weeks and birth weight of 846 ± 353 g were identified. Nine patients were on invasive mechanical ventilation and 25 patients were on non-invasive respiratory support at prednisolone initiation. Prednisolone was initiated at a mean post-menstrual age of 41.7 ± 5 weeks and a mean dose of 1.7 ± 0.6 mg/kg/day. A significant decrease in PSS was seen over time (p < 0.001) without rebound following discontinuation. Eleven patients decreased the mode of respiratory support during prednisolone treatment. No significant impact in anthropometric outcomes were identified.

CONCLUSION

Prolonged prednisolone use was associated with a sustained decrease in PSS without adverse effects on growth measurements. These results suggest potential benefit of prednisolone on respiratory outcomes in a subset of preterm infants.

Revisiting the definition of bronchopulmonary dysplasia in premature infants at a single center quaternary neonatal intensive care unit

OBJECTIVE

To compare the incidence of bronchopulmonary dysplasia (BPD) based on the 1988 Vermont Oxford Network (VON) criteria, National Institutes of Health (NIH) 2001 definition, and NIH 2018 definition.

METHODS

BPD incidence by each definition was compared in premature infants born at a single center between 2016 and 2018. Comorbidities were compared between those with and without BPD according to the newest definition.

RESULTS

Among 352 survivors, BPD incidence was significantly different at 9%, 28% and 34% according to VON, NIH 2001 and NIH 2018 definitions, respectively (p < 0.05). According to the newest definition, any grade of BPD was associated with more co-morbidities than those without BPD (P < 0.001).

CONCLUSION

At a center that emphasizes use of early noninvasive respiratory support, the incidence of BPD was significantly higher according to the NIH 2018 definition compared to other two definitions. The relationship between BPD diagnosis and long-term clinical outcomes remains unclear.

Multimodal longitudinal respiratory function assessment in very low birth weight 7-year-old children

PURPOSE

Preterm birth is associated with adverse pulmonary outcomes. We aimed to evaluate respiratory morbidities and lung function of very low birth weight (VLBW) Polish children followed up at the age of 7 years old, and to compare with electrical impedance segmentography (EIS) results recorded at 4 years of age.

MATERIALS AND METHODS

VLBW children were compared with term controls using impulse oscillometry and spirometry. Perinatal data and current respiratory morbidities were analyzed and pulmonary function test results were compared with previous EIS results.

RESULTS

We included 40 VLBW children and 30 controls in the analysis. Elevated total airway resistance and forced expiratory volume in the first second below the lower limit of normal were more prevalent in VLBW children compared with term controls (15 vs 0%; 18 vs 0%). A positive bronchodilator response was more common in VLBW children (R_{5 Hz}: 46 vs 13.3%; R_5-20 ​Hz: 65 vs 36.7%). Children with bronchopulmonary dysplasia (BPD) had higher total airway resistance (R_{5 Hz}/R_{5 Hz pred}: 1.35 vs 0.95; p ​< ​0.001), large airway resistance (R_{20 Hz}/R_{20 Hz pred}: 0.89 vs 0.66; p ​= ​0.001), small airway resistance (R_5-20 ​Hz: 0.57 vs 0.34 ​kPa ​L^-1 ​s^-1; p ​= ​0.009), than controls. Strong correlation between BDR in EIS and R_{5 Hz}/R_{5 Hz pred} was observed in children with BPD (r ​= ​0.7).

CONCLUSION

VLBW school-aged children with BPD presented with substantial respiratory morbidity and persistent reduction of lung function, affecting small and large airways and lung parenchyma. EIS may be an alternative tool for lung function assessment in children with BPD.

Telomere length shortening in hospitalized preterm infants: A pilot study

Leukocyte telomere length is a biomarker of aging-related health risks. Hospitalized preterm infants frequently experience elevated oxidative stress and inflammation, both of which contribute to telomere shortening. Our aim was to examine changes in telomere length during neonatal intensive care unit (NICU) hospitalization in a cohort of preterm infants <32 weeks' gestation. We conducted a longitudinal study of 10 infants (mean gestational age 27 weeks, range 23.5 to 29, at birth). We isolated DNA from dried blood spots and used Real Time Quantitative PCR to measure relative leukocyte telomere length in triplicate at three time points for each participant. From birth to discharge, infants experienced an average decline in relative telomere length of 0.021 units per week (95% CI -0.040, -0.0020; p = 0.03), after adjustment for gestational age at birth. Our results suggest a measurable decline in telomere length during NICU hospitalization. We speculate that telomere length change may convey information about NICU exposures that carry short- and long-term health risks.

Pulmonary Gas Exchange Improves over the First Year in Preterm Infants with and without Bronchopulmonary Dysplasia

BACKGROUND

Right shift of the peripheral oxyhaemoglobin saturation (SpO2) versus inspired oxygen pressure (PIO2) curve is a sensitive marker of pulmonary gas exchange.

OBJECTIVES

The aim of this study was to assess the impact of prematurity and bronchopulmonary dysplasia (BPD) on gas exchange and right-to-left shunt in the neonatal period, and its evolution over the first year of life.

METHOD

We assessed shift and shunt in extremely preterm (EP) and very preterm (VP) infants at 36 and 44 weeks' postmenstrual age (PMA), and at 1-year corrected postnatal age (cPNA). PIO2 was decreased stepwise to achieve SpO2 between 85 and 98%. Shift and shunt were calculated from paired SpO2/PIO2 measurements using customized software. Results were examined cross-sectionally at each time point, and longitudinally using generalized linear regression. Term infants were assessed at 44 wk PMA as a comparative reference.

RESULTS

Longitudinal modelling showed continuous decline in shift in EP and VP infants during the first year of life. There was no difference in shift compared to term infants at 44 wk PMA (p = 0.094). EP infants with BPD had higher shift than infants without BPD at 36 wk PMA (p < 0.001) and 44 wk PMA (p = 0.005) but not at 1-year cPNA.

CONCLUSIONS

In the absence of lung disease, prematurity per se did not result in reduced gas exchange at 1-year cPNA. We report ongoing, significant improvements in pulmonary gas exchange in all preterm infants during the first year of life, despite evidence of early deficits in gas exchange in EP infants with BPD.

Long-term respiratory and developmental outcomes in children with bronchopulmonary dysplasia and history of tracheostomy

OBJECTIVE

The long-term morbidity among children with severe bronchopulmonary dysplasia who require tracheostomy (tBPD) relative to those without tracheostomy (sBPD) is not well characterized. We compared childhood lung function and neurodevelopmental outcomes in tBPD and sBPD.

STUDY DESIGN

Retrospective case-control study of N = 49 tBPD and N = 280 sBPD subjects in Boston Children's Hospital Preterm Lung Patient Registry and medical record. We compared NICU course, childhood spirometry, and neurodevelopmental testing.

RESULT

tBPD subjects were more likely than sBPD to be Black, have pulmonary hypertension, and have subglottic stenosis. tBPD subjects had lower maximal childhood FEV₁ % predicted (β = -0.14) and FEV₁/FVC (β = -0.08); spirometry curves were more likely to suggest fixed extrathoracic obstruction. tBPD subjects had greater cognitive and motor delays <24 months, and greater cognitive delays >24 months.

CONCLUSION

Compared to subjects with sBPD who did not require tracheostomy, tBPD subjects suffer from increased long-term impairment in respiratory function and neurodevelopment.

Predicting Long-Term Respiratory Outcomes in Premature Infants: Is It Time to Move beyond Bronchopulmonary Dysplasia?

Premature birth has been shown to be associated with adverse respiratory health in children and adults; children diagnosed with bronchopulmonary dysplasia (BPD) in infancy are at particularly high risk. Since its first description by Northway et al. about half a century ago, the definition of BPD has gone through several iterations reflecting the changes in the patient population, advancements in knowledge of lung development and injury, and improvements in perinatal care practices. One of the key benchmarks for optimally defining BPD has been the ability to predict long-term respiratory and health outcomes. This definition is needed by multiple stakeholders for hosts of reasons including: providing parents with some expectations for the future, to guide clinicians for developing longer term follow-up practices, to assist policy makers to allocate resources, and to support researchers involved in developing preventive or therapeutic strategies and designing studies with meaningful outcome measures. Long-term respiratory outcomes in preterm infants with BPD have shown variable results reflecting not only limitations of the current definition of BPD, but also potentially the impact of other prenatal, postnatal and childhood factors on the respiratory health. In this manuscript, we present an overview of the long-term respiratory outcomes in infants with BPD and discuss the role of other modifiable or non-modifiable factors affecting respiratory health in preterm infants. We will also discuss the limitations of using BPD as a predictor of respiratory morbidities and some of the recent advances in delineating the causes and severity of respiratory insufficiency in infants diagnosed with BPD.

Preschool Asthma Symptoms in Children Born Preterm: The Relevance of Lung Function in Infancy

Background: The aim of the study is to assess whether lung function of infants born preterm predicts wheezing in pre-school age. Methods: A survey of the core wheezing questionnaire of the International Study on Asthma and Allergy in Children was administered to parents of preterm newborns, to whom lung function tests were performed at a corrected age of six months, and who, at the time of the survey, were between three and nine years of age. Results: Low values of all lung function parameters measured, except FVC, were predictors of wheezing at some time in life, (FEV0.5 OR: 0.62 (95%CI 0.39; 0.995); FEV0.5/FVC OR: 0.73 (0.54; 0.99)) FEF75 OR: 0.60 [0.37; 0.93]; FEF25-75 OR: 0.57 (0.37; 0.89)); and of wheezing in the past year (FEV0.5 OR: 0.36 (0.17; 0.76); FEV0.5/FVC OR: 0.59 (0.38; 0.93); FEF75 OR: 0.38 [0.19; 0.76]; FEF25-75 OR: 0.35 (0.17; 0.70). In addition, FEV0.5/FVC values lower than the lowest limit of normality, were predictive of hospital admissions due to wheezing (OR: 3.07; (1.02; 9.25)). Conclusions: Limited lung function in infancy is predictive of both future wheezing and hospitalization for a wheezing episode.

Correlation between chorionic plate vascularization and risk of bronchopulmonary dysplasia in extremely preterm infants

INTRODUCTION/OBJECTIVES

The chorionic plate vessels of the placenta are in direct continuity with the fetal vasculature, suggesting chorionic and fetal angiogenesis may be subjected to similar regulatory mechanisms. In this study, we determined the correlation between chorionic plate vascularization and complications of prematurity, focusing on bronchopulmonary dysplasia (BPD) and other conditions with important microvascular components.

METHODS

We performed a clinicoplacental analysis of 127 extremely preterm infants (23-28 weeks gestation). Chorionic plate vascularization was assessed by number and density of perforating chorionic vessels (PCVs). Charts were reviewed for relevant maternal and neonatal data, including respiratory, neurologic and gastrointestinal complications of prematurity.

RESULTS

The placentas displayed marked variability in number (36-523/placenta) and density of PCVs (0.46-3.74 PC V/cm²). The median PCV density of infants with severe BPD was significantly higher than that of infants without BPD (1.51 PC V/cm² versus 1.09 PC V/cm², P < 0.05). Conversely, the frequency of moderate-to-severe BPD was 33% higher in infants with PCV density ≥1.50 PC V/cm² than in those with PCV density <1.50 PC V/cm² (56% versus 40%, P < 0.01). There was no correlation with neonatal neurologic or gastrointestinal complications.

CONCLUSION

Chorionic plate vascularization correlates with frequency and severity of BPD, supporting a vascular basis that in part is antenatal in origin. Quantitative assessment of chorionic plate vascularization may allow early identification of preterm infants at high risk for BPD (proposed threshold: PCV density ≥1.50 PC V/cm²). The lack of correlation between chorionic vascularization and neurologic/gastrointestinal complications suggests these conditions may have less important antenatal and/or vascular contributions.

Lung imaging in bronchopulmonary dysplasia: a systematic review

BACKGROUND

Bronchopulmonary dysplasia (BPD) remains a common complication of preterm birth. Both historically and in current practice, radiologic evaluation of the lungs has an important role in assessing disease severity and complications.

AIM

To provide an overview of imaging techniques for detecting lung abnormalities in patients with BPD in all age ranges.

METHODS

A systematic literature search was conducted in PubMed, Web of Science and the Cochrane Library. Records were screened by title and abstract and then by full text. A total of 37 records were selected and included in this qualitative literature overview.

RESULTS

Computed tomography (CT) was the most commonly used imaging modality, followed by chest radiography and magnetic resonance imaging (MRI). Several qualitative and quantitative scoring systems were presented and most showed good correlation with BPD severity. The association with functional and clinical outcomes was only rarely reported, showing varying correlation with spirometry results and respiratory exacerbations. MRI is an upcoming imaging technique for BPD that is technically feasible, showing clear differences in the lung parenchyma of patients with BPD.

CONCLUSION

Several imaging and scoring methods indicate that lung imaging continues to play a role in BPD care. Standardization and correlation with functional and clinical outcomes will become increasingly important for further research.

Exercise capacity in children with bronchopulmonary dysplasia at school age

OBJECTIVE

To assess the exercise capacity, exercise habits, and lung function of preterm born children with bronchopulmonary dysplasia (BPD) compared to term born controls at school age.

METHODS

Cardiopulmonary exercise test (CPET) by cycle ergometer and pulmonary function test were performed in children with BPD (n = 42) and compared with a term born control group (n = 42). Daily activity, participation in sports and respiratory symptoms were assessed by questionnaire.

RESULTS

Children with BPD versus controls had significantly lower values for oxygen consumption (V̇O₂ [mL/min] 1442 ± 417 vs. 1766 ± 541), minute ventilation (VE [L/min] 48 ± 14.92 vs. 60 ± 18.33), and workload (W [watt] 96.1 ± 16.7 vs. 110.6 ± 17.2) at peak exercise and a lower anaerobic threshold (VO₂ AT [mL/min] 1183 ± 345 vs. 1382 ± 398). When corrected for weight, only for the workload (2.7 ± 0.5 vs. 3.1 ± 0.5, p = 0.0013) did significant differences persist. The forced expiratory volume in 1 s and forced expiratory flow between 25 and 75% of expired forced vital capacity were significantly reduced in the BPD group (p < 0.0001). Children with BPD have a higher risk of reporting difficulties in physical activity (OR 2.5) and of suffering from wheezing or shortness of breath while exercising (OR 2.5).

CONCLUSION

Compared to term born controls, children with BPD at school age show airflow obstruction, a lower workload in CPET, and more respiratory symptoms related to physical activity. The comparable oxygen consumption based on weight suggests a functionally normal alveolar compartment.

Early Neonatal Oxygen Exposure Predicts Pulmonary Morbidity and Functional Deficits at 1 Year

OBJECTIVE

To evaluate the predictive value of cumulative oxygen exposure thresholds over the first 2 postnatal weeks, linking them to bronchopulmonary dysplasia (BPD) and 1-year pulmonary morbidity and lung function in extremely low gestational age newborns.

STUDY DESIGN

Infants (N = 704) enrolled in the Prematurity and Respiratory Outcomes Program, a multicenter prospective cohort study, that survived to discharge were followed through their neonatal intensive care unit hospitalization to 1-year corrected age. Cumulative oxygen exposure (Oxygen_AUC14) thresholds were derived from univariate models of BPD, stratifying infants into high-, intermediate-, and low-oxygen exposure groups. These groups were then used in multivariate logistic regressions to prospectively predict post-prematurity respiratory disease (PRD), respiratory morbidity score (RMS) in the entire cohort, and pulmonary function z scores (N = 108 subset of infants) at 1-year corrected age.

RESULTS

Over the first 14 postnatal days, infants exposed to high oxygen averaged ≥33.1% oxygen, infants exposed to intermediate oxygen averaged 29.1%-33.1%, and infants exposed to low oxygen were below both cutoffs. In multivariate models, infants exposed to high oxygen showed increased PRD and RMS, whereas infants exposed to intermediate oxygen demonstrated increased moderate/severe RMS. Infants in the high/intermediate groups had decreased forced expiratory volume at 0.5 seconds/forced vital capacity ratio.

CONCLUSIONS

Oxygen_AUC14 establishes 3 thresholds of oxygen exposure that risk stratify infants early in their neonatal course, thereby predicting short-term (BPD) and 1-year (PRD, RMS) respiratory morbidity. Infants with greater Oxygen_AUC14 have altered pulmonary function tests at 1 year of age, indicating early evidence of obstructive lung disease and flow limitation, which may predispose extremely low gestational age newborns to increased long-term pulmonary morbidity.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01435187.