Present and Future of Bronchopulmonary Dysplasia

Exploring research trends and hotspots on oxidative stress and bronchopulmonary dysplasia: Insights from bibliometric and visualized study

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a severe chronic lung disease primarily affecting premature infants, often resulting from prolonged mechanical ventilation and oxygen therapy. Oxidative stress plays a critical role in the pathogenesis of BPD, contributing to lung injury, inflammation, and impaired lung development. Despite extensive research, there is a need to systematically map out the research trends and hotspots in this field to inform future studies and therapeutic strategies.

METHODS

This study utilized bibliometric and visualized analysis to explore global research trends and hotspots on oxidative stress and BPD from 2004 to 2024. A comprehensive literature search was conducted in the Web of Science Core Collection, focusing on publications related to oxidative stress and BPD. Tools such as VOSviewer, Citespace, and the R package Bibliometrix were employed to analyze Coauthorship, co-citation, and keyword co-occurrence networks, as well as to identify emerging research fronts and influential studies.

RESULTS

The analysis identified 597 relevant publications, showing a steady increase in research output over the 20-year period, with a significant surge in the last decade. The United States led in research contributions, followed by China and Germany, with notable collaborations among these countries. Coauthorship analysis highlighted key research institutions, such as Harvard University and the University of California, as central nodes in the research network. Thematic clustering revealed five major research areas: antioxidant mechanisms, inflammation, molecular pathways, lung development, and therapeutic interventions. The keyword co-occurrence analysis showed a shift in research focus over time. Early studies concentrated on basic pathophysiological mechanisms, while recent research has increasingly focused on advanced molecular techniques, such as gene expression and targeted therapies. Notably, the study identified emerging research hotspots, including the role of extracellular vesicles and cellular senescence in BPD, as well as the potential therapeutic applications of antioxidants like superoxide dismutase mimetics.

CONCLUSION

This bibliometric study provides a comprehensive overview of the research landscape on oxidative stress and BPD, identifying key trends, influential authors, and emerging research topics. The findings underscore the importance of continued research in this field, particularly in translating basic scientific insights into clinical applications to improve outcomes for infants affected by BPD. The study also highlights potential areas for future investigation, including the development of novel therapeutic strategies targeting oxidative stress in BPD.

Risk factors and clinical outcomes of pulmonary hypertension associated with bronchopulmonary dysplasia in extremely premature infants: A systematic review and meta-analysis

This systematic review and meta-analysis evaluated the risk factors for bronchopulmonary dysplasia associated pulmonary hypertension (BPD-PH) in extremely premature infants (gestational age < 32 weeks) and its impact on outcomes. A computerized search of eight databases was performed, from the time of library construction to February 2024. The quality of the included studies was assessed with the Newcastle‒Ottawa scale. Statistical analyses were performed using RevMan 5.4.1 and Stata 16.0 software. Meta-analysis of 2137 extremely premature infants revealed that oligohydramnios (OR = 2.21, 95% CI 1.06-4.61), low gestational age (SMD = -0.36, 95% CI -0.47 to -0.24), low birth weight (SMD = -0.54, 95% CI -0.74 to -0.35), small for gestational age (OR = 1.61, 95% CI 1.06-2.44), neonatal respiratory distress syndrome (OR = 2.05, 95% CI 1.45-2.91), grade III bronchopulmonary dysplasia (OR = 4.67, 95% CI 1.34-16.30), and sepsis (OR = 2.25, 95% CI 1.69-4.66) were risk factors for BPD-PH, whereas antenatal steroids (OR = 0.66, 95% CI 0.49-0.88) were protective factors. BPD-PH led to the extension of oxygen therapy (SMD = 0.67, 95% CI 0.42-0.92) and hospital stay (SMD = 0.77, 95% CI 0.14-1.40), and elevated the risk of discharged on oxygen (OR = 2.77, 95% CI 1.35-5.70) and death (OR = 4.38, 95% CI 2.21-8.69). BPD-PH is a multifactorial disease. In this study, a total of seven risk factors, and one protective factor for BPD-PH were identified in extremely premature infants. By managing and mitigating these factors, it is possible to decrease the occurrence of BPD-PH. Furthermore, BPD-PH may increase the risk of a poor prognosis in extremely premature infants.

Antibiotics and beyond: Unraveling the dynamics of bronchopulmonary dysplasia in very preterm infants

BACKGROUND

Bronchopulmonary dysplasia (BPD) remains a significant challenge in neonatal care. Prenatal inflammation and neonatal sepsis contribute to the multifactorial nature of BPD. A potential association between empirical antibiotic therapy and BPD risk has been proposed due to microbiota dysbiosis in very low birth weight premature infants.

METHODS

A single centered retrospective cohort study of preterm infants (24-32 weeks gestation) from 2014 to 2021. The study compared groups that received empirical antibiotics in the first days of life and those that did not receive any antibiotic in the first days of life. The primary outcomes studied were BPD, death, and the combined outcome of BPD/death. Statistical analysis employed t-tests, Mann-Whitney U, Chi-square, and logistic regression.

RESULTS

Of 454 preterm infants, 61.5% received antibiotics. This group had lower gestational age, birth weight, and Apgar scores. Antibiotic use was associated with higher incidence of BPD (35.5% vs. 10.3%), death (21.5% vs. 8.6%), and combined outcomes (54.5% vs. 18.3%). In multivariate analysis, antibiotic use independently associated with BPD (OR 2.58, p < 0.001) and combined outcome BPD/death (OR 2.06, p < 0.02). Antenatal corticosteroids provided protection against BPD, but not mortality.

CONCLUSION

This study suggests an association between early empirical antibiotic use and BPD in preterm infants, emphasizing the need for judicious antibiotic practices in neonatal care.

Multicentre online registration of bronchopulmonary dysplasia in very preterm infants in China: protocol for a prospective, open, observational cohort study

INTRODUCTION

Bronchopulmonary dysplasia (BPD) in very preterm infants (VPIs) has adverse long-term outcomes and affects the quality of survival. There are no registry studies on BPD in VPIs in China. Our aim was to conduct a prospective, multicentre, open, longitudinal, observational cohort study to investigate the epidemiological characteristics, diagnosis, treatment, and short-term and long-term outcomes of BPD in a real-life setting in China and lay the grounds for establishing a nationwide registry with clinical data and biological specimens.

METHODS

This study aims to recruit a minimum of 2000 VPIs and start research in January 2024 in Shenzhen, China. We will collect clinical data from the beginning of the life of VPIs and follow them up to 3 years old. Short-term outcomes, such as the incidence of BPD, necrotising enterocolitis, retinopathy of prematurity, intraventricular haemorrhage and porencephalic ventricular leukomalacia, as well as the cost of hospitalisation, are the major variables of concern. Bayley-III Scale assessment, gross motor function and pulmonary function evaluation will be performed at the age of correction, that is, 18-24 months and 30-36 months. The follow-up outcomes include loss to follow-up, survival status, moderate-to-severe neurodevelopmental deficits and severe respiratory complications. Cord blood, peripheral blood, tracheal aspirate, faeces and urine from VPIs, as well as mother's milk, will be collected and stored at -80°C. All the data will be registered, stored and managed in a cloud-based database. This knowledge will be useful for establishing diagnostic criteria and predictive models for BPD in the Chinese population.

ETHICS AND DISSEMINATION

Our protocol has been approved by the Medical Ethics Committee of Shenzhen People's Hospital (LL-KY-2023174-02) and the local ethics committee of each participating centre. Our goal is to present our findings at national conferences and in peer-reviewed paediatric journals.

TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Registry (ChiCTR2400081615).

[Risk factors for bronchopulmonary dysplasia in preterm infants and establishment of a prediction model]

OBJECTIVES

To investigate the risk factors for bronchopulmonary dysplasia (BPD) in preterm infants, and to establish a risk prediction model.

METHODS

A total of 120 preterm infants who were admitted to the neonatal intensive care unit of Shanghai Children's Hospital from January to December 2022 were included. According to the diagnostic criteria for BPD released by the National Institute of Child Health and Human Development in 2018, they were divided into a non-BPD group (84 infants) and a BPD group (36 infants). The clinical data of the infants and their mothers were compared between the two groups. The univariate analysis and the stepwise multivariate regression analysis were used to identify the risk factors for BPD and establish a risk prediction model.

RESULTS

The results showed that a gestational age of <28 weeks, duration of noninvasive respiratory support, comorbidity with infectious pneumonia, and chorioamnionitis in the mother were independent risk factors for BPD in preterm infants (P<0.05). A nomogram model for predicting the development of BPD was established based on the risk factors, with an area under the receiver operating characteristic curve of 0.93, and the calibration curve of this nomogram had a slope of about 1. The goodness-of-fit test indicated the model fitted well (χ2=8.287, P=0.406).

CONCLUSIONS

A gestational age of <28 weeks, duration of noninvasive respiratory support, comorbidity with infectious pneumonia, and chorioamnionitis in the mother are independent risk factors for BPD in preterm infants.

The association between VEGF genetic variations and the risk of bronchopulmonary dysplasia in premature infants: a meta-analysis and systematic review

Objective

Previous studies on the link between VEGF gene polymorphisms and bronchopulmonary dysplasia (BPD) have yielded inconsistent results. This meta-analysis sought to clarify the relationship between genetic variations in the VEGF gene and the risk of BPD.

Methods

Data were collected from multiple databases, including PubMed, Scopus, EMBASE, and CNKI, up to January 5, 2024.

Results

Nineteen case-control studies were analyzed, featuring 1,051 BPD cases and 1,726 healthy neonates. The analysis included four studies on the -460T/C polymorphism (312 cases, 536 controls), four on the -2578C/A polymorphism (155 cases, 279 controls), six on the +405G/C polymorphism (329 cases, 385 controls), and five on the +936C/T polymorphism (225 cases, 526 controls). The meta-analysis suggests that the -460T/C polymorphism may protect against BPD (C vs. T: OR = 0.715, 95% CI 0.543-0.941, p = 0.017; CC vs. TT: OR = 0.478, 95% CI 0.233-0.983, p = 0.045; CC vs. CT + TT: OR = 0.435, 95% CI 0.248-0.764, p = 0.004). No significant associations were found between the -2578C/A, +405G/C, and +936C/T polymorphisms and BPD susceptibility.

Conclusions

This meta-analysis indicates that the C allele of the -460T/C polymorphism may offer protection against BPD. No significant associations were observed for the -2578C/A, +405G/C, and +936C/T polymorphisms.

Optimized lung expansion ventilation modulates ventilation-induced lung injury in preterm lambs

INTRODUCTION

Preterm infants close to viability commonly require mechanical ventilation (MV) for respiratory distress syndrome. Despite commonly used lung-sparing ventilation techniques, rapid lung expansion during MV induces lung injury, a risk factor for bronchopulmonary dysplasia. This study investigates whether ventilation with optimized lung expansion is feasible and whether it can further minimize lung injury. Therefore, optimized lung expansion ventilation (OLEV) was compared to conventional volume targeted ventilation.

METHODS

Twenty preterm lambs were surgically delivered after 132 days of gestation. Nine animals were randomized to receive OLEV for 24 h, and seven received standard MV. Four unventilated animals served as controls (NV). Lungs were sampled for histological analysis at the end of the experimental period.

RESULTS

Ventilation with OLEV was feasible, resulting in a significantly higher mean ventilation pressure (0.7-1.3 mbar). Temporary differences in oxygenation between OLEV and MV did not reach clinically relevant levels. Ventilation in general tended to result in higher lung injury scores compared to NV, without differences between OLEV and MV. While pro-inflammatory tumor necrosis factor-α messenger RNA (mRNA) levels increased in both ventilation groups compared to NV, only animals in the MV group showed a higher number of CD45-positive cells in the lung. In contrast, mean (standard deviations) surfactant protein-B mRNA levels were significantly lower in OLEV, 0.63 (0.38) compared to NV 1.03 (0.32) (p = .023, one-way analysis of variance).

CONCLUSION

In conclusion, a small reduction in pulmonary inflammation after 24 h of support with OLEV suggests potential to reduce preterm lung injury.

Correlation between Bronchopulmonary Dysplasia and Cerebral Palsy in Children: A Comprehensive Analysis Using the National Inpatient Sample Dataset

Background: The existing literature lacks conclusive evidence regarding the relationship between bronchopulmonary dysplasia (BPD) and cerebral palsy (CP). This large epidemiological study aimed to explore the co-occurrence of BPD and CP among children. Methods: This retrospective cohort analysis utilized the National Inpatient Sample (NIS) dataset from 2016 to 2019, investigating pediatric patients with BPD and CP diagnoses. Descriptive and inferential statistics, including univariate and multivariate regression analyses, were conducted to explore the association between BPD and CP. Results: Overall, 3,951,039 patients were analyzed. Among them, 28,880 patients had CP (n = 796 with BPD and n = 28,084 without BPD). The rates of intraventricular hemorrhage grade 3 and 4, central nervous system anomalies, chromosomal disorders, retinopathy of prematurity (≥grade 3), periventricular leukomalacia, prematurity, and low birth weight were significantly higher in the CP-with-BPD arm contrasted to the CP-without-BPD arm. Univariate regression demonstrated a significant BPD-CP association (odds ratio [OR] = 7.78, 95% confidence interval [CI]: 7.24-8.37, p < 0.0001). Multivariate analysis, adjusting for various confounders, reinforced this association (OR = 5.70, 95% CI: 5.17-6.28, p < 0.0001). We observed a significant association between increasing prematurity in neonates with BPD and an elevated risk of CP. Conclusions: This nationwide study identified a strong correlation between the co-occurrence of BPD and CP, though it does not establish causality. Rigorous adjustments revealed that patients with BPD appear to have a six-fold increased likelihood of being diagnosed with CP later on, compared to those without BPD. While aligned with the existing literature, this study represents the largest sample size with recommendations for targeted preventive strategies to mitigate the burden of CP.

Predictive value of serum MED1 and PGC-1α for bronchopulmonary dysplasia in preterm infants

OBJECTIVE

This study aimed to predict the bronchopulmonary dysplasia (BPD) in preterm infants with a gestational age(GA) < 32 weeks utilizing clinical data, serum mediator complex subunit 1 (MED1), and serum peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1α).

METHODS

This prospective observational study enrolled 70 preterm infants with GA < 32 weeks. The infants were categorized into two groups: non-BPD group(N = 35) and BPD group(N = 35), including 25 cases with mild BPD and 10 patients with moderate/severe subgroups. We performed multifactorial regression analysis to investigate the postnatal risk factors for BPD. Furthermore, we compared serum levels of biomarkers, including MED1 and PGC-1α, among infants with and without BPD at postnatal days 1, 7, 14, 28, and PMA 36 weeks. A logistic regression model was constructed to predict BPD's likelihood using clinical risk factors and serum biomarkers.

RESULTS

Serum levels of MED1 on the first postnatal day, PGC-1α on the 1st, 7th, and 28th days, and PMA at 36 weeks were significantly lower in the BPD group than in the non-BPD group (P < 0.05). Furthermore, the predictive model for BPD was created by combing serum levels of MED1 and PGC-1α on postnatal day 1 along with clinical risk factors such as frequent apnea, mechanical ventilation time > 7 d, and time to reach total enteral nutrition. Our predictive model had a high predictive accuracy(C statistics of 0.989) .

CONCLUSION

MED1and PGC-1α could potentially serve as valuable biomarkers, combined with clinical factors, to aid clinicians in the early diagnosis of BPD.

Role of Myeloperoxidase, Oxidative Stress, and Inflammation in Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a lung complication of premature births. The leading causes of BPD are oxidative stress (OS) from oxygen treatment, infection or inflammation, and mechanical ventilation. OS activates alveolar myeloid cells with subsequent myeloperoxidase (MPO)-mediated OS. Premature human neonates lack sufficient antioxidative capacity and are susceptible to OS. Unopposed OS elicits inflammation, endoplasmic reticulum (ER) stress, and cellular senescence, culminating in a BPD phenotype. Poor nutrition, patent ductus arteriosus, and infection further aggravate OS. BPD survivors frequently suffer from reactive airway disease, neurodevelopmental deficits, and inadequate exercise performance and are prone to developing early-onset chronic obstructive pulmonary disease. Rats and mice are commonly used to study BPD, as they are born at the saccular stage, comparable to human neonates at 22-36 weeks of gestation. The alveolar stage in rats and mice starts at the postnatal age of 5 days. Because of their well-established antioxidative capacities, a higher oxygen concentration (hyperoxia, HOX) is required to elicit OS lung damage in rats and mice. Neutrophil infiltration and ER stress occur shortly after HOX, while cellular senescence is seen later. Studies have shown that MPO plays a critical role in the process. A novel tripeptide, N-acetyl-lysyltyrosylcysteine amide (KYC), a reversible MPO inhibitor, attenuates BPD effectively. In contrast, the irreversible MPO inhibitor-AZD4831-failed to provide similar efficacy. Interestingly, KYC cannot offer its effectiveness without the existence of MPO. We review the mechanisms by which this anti-MPO agent attenuates BPD.

Deficiency of Secreted Phosphoprotein 1 Alleviates Hyperoxia-induced Bronchopulmonary Dysplasia in Neonatal Mice

Bronchopulmonary dysplasia (BPD) is a common chronic lung disorder characterized by impaired proximal airway and bronchoalveolar development in premature births. Secreted phosphoprotein 1 (SPP1) is involved in lung development and lung injury events, while its role was not explored in BPD. For establishing the in vivo models of BPD, a mouse model of hyperoxia-induced lung injury was generated by exposing neonatal mice to hyperoxia for 7 days after birth. Alveolar myofibroblasts (AMYFs) were treated with hyperoxia to establish the in vitro models of BPD. Based on the scRNA-seq analysis of lungs of mice housed under normoxia or hyperoxia conditions, mouse macrophages and fibroblasts were main different cell clusters between the two groups, and differentially expressed genes in fibroblasts were screened. Further GO and KEGG enrichment analysis revealed that these differentially expressed genes were mainly enriched in the pathways related to cell proliferation, apoptosis as well as the PI3K-AKT and ERK/MAPK pathways. SPP1 was found up-regulated in the lung tissues of hyperoxia mice. We also demonstrated the up-regulation of SPP1 in the BPD patients, the mouse model of hyperoxia-induced lung injury, and hyperoxia-induced cells. SPP1 deficiency was revealed to reduce the hyperoxia-induced apoptosis, oxidative stress and inflammation and increase the viability of AMYFs. In the mouse model of hyperoxia induced lung injury, SPP1 deficiency was demonstrated to reverse the hyperoxia-induced alveolar growth disruption, oxidative stress and inflammation. Overall, SPP1 exacerbates BPD progression in vitro and in vivo by regulating oxidative stress and inflammatory response via the PI3K-AKT and ERK/MAPK pathways, which might provide novel therapeutic target for BPD therapy.

Antimicrobial Peptides (AMPs) and the Microbiome in Preterm Infants: Consequences and Opportunities for Future Therapeutics

Antimicrobial peptides (AMPs) are crucial components of the innate immune system in various organisms, including humans. Beyond their direct antimicrobial effects, AMPs play essential roles in various physiological processes. They induce angiogenesis, promote wound healing, modulate immune responses, and serve as chemoattractants for immune cells. AMPs regulate the microbiome and combat microbial infections on the skin, lungs, and gastrointestinal tract. Produced in response to microbial signals, AMPs help maintain a balanced microbial community and provide a first line of defense against infection. In preterm infants, alterations in microbiome composition have been linked to various health outcomes, including sepsis, necrotizing enterocolitis, atopic dermatitis, and respiratory infections. Dysbiosis, or an imbalance in the microbiome, can alter AMP profiles and potentially lead to inflammation-mediated diseases such as chronic lung disease and obesity. In the following review, we summarize what is known about the vital role of AMPs as multifunctional peptides in protecting newborn infants against infections and modulating the microbiome and immune response. Understanding their roles in preterm infants and high-risk populations offers the potential for innovative approaches to disease prevention and treatment.

Myeloid Nrf2 Protects against Neonatal Oxidant-Stress-Induced Lung Inflammation and Alveolar Simplification in Mice

Bronchopulmonary dysplasia (BPD) is a chronic condition affecting preterm infants, characterized by lung alveolar simplification/hypoalveolarization and vascular remodeling. The nuclear factor erythroid 2 like 2 (Nfe2l2, or Nrf2) plays a critical role in the cytoprotective response to neonatal hyperoxia, and its global deficiency exacerbates hypoalveolarization in mice. The abnormal recruitment and activation of myeloid cells are associated with the pathogenesis of BPD. Therefore, we employed a genetic approach to investigate the role of myeloid Nrf2 in regulating hyperoxia-induced hypoalveolarization. Pups, both wild-type (Nrf2f/f) and those with a myeloid Nrf2 deletion (abbreviated as Nrf2∆/∆mye), were exposed to hyperoxia for 72 h at postnatal day 1 (Pnd1), and then sacrificed at either Pnd4 or Pnd18 following a two-week recovery period. We analyzed the hypoalveolarization, inflammation, and gene expression related to cytoprotective and inflammatory responses in the lungs of these pups. The hypoalveolarization induced by hyperoxia was significantly greater in Nrf2∆/∆mye pups compared to their Nrf2f/f counterparts (35.88% vs. 21.01%, respectively) and was accompanied by increased levels of inflammatory cells and IL-1β activation in the lungs. Antioxidant gene expression in response to neonatal hyperoxia was lower in Nrf2∆/∆mye pups compared to their Nrf2f/f counterparts. Furthermore, Nrf2-deficient macrophages exposed to hyperoxia exhibited markedly decreased cytoprotective gene expression and increased IL-1β levels compared to Nrf2-sufficient cells. Our findings demonstrate the crucial role of myeloid Nrf2 in mitigating hyperoxia-induced lung hypoalveolarization and inflammatory responses in neonatal mice.

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.

Efficacy and safety of different inhaled corticosteroids for bronchopulmonary dysplasia prevention in preterm infants: A systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis aimed to evaluate the efficacy and safety of inhaled corticosteroids (budesonide, beclomethasone, or fluticasone propionate) in preventing bronchopulmonary dysplasia (BPD) for premature infants.

METHOD

Electronic databases, including PubMed, EMBASE, Web of science, Scopus, and Cochrane library, were searched from databases inception to January 2022 for eligible randomized controlled trials. Clinical outcomes such as BPD, mortality, BPD or death, adverse events, and neurodevelopmental outcomes were assessed.

RESULTS

Overall, budesonide was significantly associated with a reduction in BPD at 36 weeks' postmenstrual age (RR 0.48; 95 % CI [0.38, 0.62]) and patent ductus arteriosus (PDA) (RR 0.75; 95 % CI [0.63, 0.89]) compared with control treatments. Early longer duration inhalation of budesonide alone was associated with a lower risk of BPD at 36 weeks' postmenstrual age and PDA compared with controls. Early shorter duration intratracheal instillation of budesonide with surfactant as vehicle was associated with a lower risk of BPD at 36 weeks' postmenstrual age and all-cause mortality compared with surfactant. There was no statistically significant difference between budesonide and control groups regarding neurodevelopmental impairment. Beclomethasone and fluticasone propionate did not show any superior or inferior effect on clinical outcomes compared to control treatments.

CONCLUSION

These findings suggest that budesonide, especially intratracheal instillation of budesonide using surfactant as a vehicle, is a safe and effective option in preventing BPD for preterm infants. More well-design large-scale trials with long-term follow-ups are necessary to verify the present findings.

Urine Desmosine as a Novel Biomarker for Bronchopulmonary Dysplasia and Postprematurity Respiratory Disease in Extremely Preterm or Low Birth Weight Infants

OBJECTIVE

This study aimed to evaluate whether elevated urine desmosine levels at 3 weeks of age were associated with severe radiological findings, bronchopulmonary dysplasia (BPD), and post-prematurity respiratory disease (PRD) in extremely preterm (EP) or extremely low birth weight (ELBW) infants.

STUDY DESIGN

This study recruited 37 EP (22-27 completed weeks) or ELBW (<1,000 g) infants. Urine was collected between 21 and 28 postnatal days, and desmosine was measured using an enzyme-linked immunosorbent assay kit; the urine creatinine level was also measured. Bubbly/cystic lungs were characterized by emphysematous chest X-rays on postnatal day 28. Furthermore, provision of supplemental oxygen or positive-pressure respiratory support at 40 weeks' postmenstrual age defined BPD, and increased medical utilization at 18 months of corrected age defined PRD. The desmosine/creatinine threshold was determined by receiver operating characteristic analysis. The adjusted risk and 95% confidence interval (CI) for elevated urine desmosine/creatinine levels were estimated by logistic regression analysis.

RESULTS

Elevated urine desmosine/creatinine levels higher than the threshold were significantly associated with bubbly/cystic lungs (8/13 [61.5%] vs. 2/24 [8.3%], p = 0.001), BPD (10/13 [76.9%] vs. 8/24 [33.3%], p = 0.02), and PRD (6/13 [46.2%] vs. 2/24 [8.3%], p = 0.01). After adjusting for gestational age, birth weight, and sex, the urine desmosine/creatinine levels were significantly higher in those who were highly at risk of bubbly/cystic lungs (odds ratio [OR], 13.2; 95% CI, 1.67-105) and PRD (OR, 13.8; 95% CI, 1.31-144).

CONCLUSION

Elevated urine desmosine/creatinine levels on the third postnatal week were associated with bubbly/cystic lungs on day 28 and PRD at 18 months of corrected age in EP or ELBW infants.

KEY POINTS

· Urine desmosine was prospectively measured in 3-week-old EP/ELBW infants.. · Elevated urine desmosine levels were associated with emphysematous radiological findings on day 28, PRD at 18 months of corrected age.. · Urine desmosine may be a promising biomarker indicating lung damage in EP/ELBW infants..

Long-term pulmonary outcomes in BPD throughout the life-course

Respiratory disease is one of the most common complications of preterm birth. Survivors of prematurity have increased risks of morbidities and mortalities independent of prematurity, and frequently require multiple medications, home respiratory support, and subspecialty care to maintain health. Although advances in neonatal and pulmonary care have improved overall survival, earlier gestational age, lower birth weight, chorioamnionitis and late onset sepsis continue to be major factors in the development of bronchopulmonary dysplasia. These early life events associated with prematurity can have respiratory consequences that persist into adulthood. Furthermore, after initial hospital discharge, air pollution, respiratory tract infections and socioeconomic status may modify lung growth trajectories and influence respiratory outcomes in later life. Given that the incidence of respiratory disease associated with prematurity remains stable or increased, there is a need for pediatric and adult providers to be familiar with the natural history, manifestations, and common complications of disease.

Research hotspots and emerging trends in mesenchymal stem/stromal cells in bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a prevalent lung disease in neonates that is associated with numerous complications and high mortality. The promising approach to treat BPD is the use of mesenchymal stem cells (MSCs), However, the current treatment of MSCs presents safety concerns, including occlusion of blood vessels and tumorigenicity. In this study, relevant publications from the Web of Science Core Collection were downloaded in January 2023. The acquired data were analyzed and predicted for trends and hotspots in this field using CiteSpace software. Results revealed that in recent years, the focus of co-cited references has been primarily on the clinical studies of MSCs and the application of MSCs derivatives for treating BPD models. The keywords that have gained attention are extracellular vesicles and exosomes. The United States has emerged as the most influential co-authoring country in this field. Among the co-cited journals, the American Journal of Respiratory and Critical Care Medicine holds the highest influence. Thus, this study provides trends in publications, collaboration, research interests, and hotspots, and provides clues for novel ideas and strategies in to further MSCs treatments for BPD.

Extremely preterm infants born outside a provincial tertiary perinatal center and transferred postnatally associated with poor outcomes: a real-world observational study

Introduction

Extremely preterm infants (EPIs) have high morbidity and mortality, and are recommended to be born in a tertiary perinatal center (inborn). However, many EPIs in central China are born in lower-level hospitals and transferred postnatally, the outcomes of which remain to be investigated.

Methods

EPIs admitted to the Department of Neonatology, Maternal and Child Health Hospital of Hubei Province from January 2013 to December 2022 were retrospectively recruited and divided into the control (inborn) and transfer groups (born in other hospitals). The neonatal and maternal characteristics, neonatal outcomes, and the treatment of survival EPIs were analyzed.

Results

A total of 174 and 109 EPIs were recruited in the control and transfer groups, respectively. EPIs in the transfer group have a higher birth weight and a lower proportion of multiple pregnancies than the control group (all P < 0.05). The proportions of antenatal steroids, magnesium sulfate, cesarean delivery, premature rupture of membranes ≥18 h, gestational diabetes, and amniotic fluid abnormalities were lower in the transfer group (all P < 0.05). Survival rates (64.22% vs. 56.32%), proportions of severe periventricular-intraventricular hemorrhage (PIVH) (11.93% vs. 11.49%), severe bronchopulmonary dysplasia (sBPD) (21.05% vs. 20%), and severe retinopathy of prematurity (ROP) (24.77% vs. 20.11%) were similar in the transfer and control groups (all P > 0.05). However, the transfer group had higher proportions of severe birth asphyxia (34.86% vs. 13.22%, P < 0.001), PIVH (42.20% vs. 29.89%, P = 0.034), and extrauterine growth retardation (EUGR) (17.43% vs. 6.32%, P = 0.003). Less surfactant utilization was found in the transfer group among survival EPIs (70.00% vs. 93.88%, P < 0.001).

Conclusion

EPIs born outside a tertiary perinatal center and transferred postnatally did not have significantly higher mortality and rates of severe complications (severe PIVH, severe ROP, and sBPD), but there may be an increased risk of severe asphyxia, PIVH and EUGR. This may be due to differences in maternal and neonatal characteristics and management. Further follow-up is needed to compare neurodevelopmental outcomes, and it is recommended to transfer the EPIs in utero to reduce the risk of poor physical and neurological development.

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.

[Characteristics of the fetal and infant respiratory system : What the pediatric anesthetist should know]

Respiratory complications are the most frequent incidents in pediatric anesthesia after cardiac events. The pediatric respiratory physiology and airway anatomy are responsible for the particular respiratory vulnerability in this stage of life. This article explains the aspects of pulmonary embryogenesis relevant for anesthesia and their impact on the respiration of preterm infants and neonates. The respiratory distress syndrome and bronchopulmonary dysplasia are highlighted as well as the predisposition to apnea of preterm infants and neonates. Due to the anatomical characteristics, the low size ratios and the significantly shorter apnea tolerance, airway management in children frequently represents a challenge. This article gives useful assistance and provides an overview of formulas for calculating the appropriate tube size and depth of insertion. Finally, the pathophysiology and adequate treatment of laryngospasm are explained.

Prophylactic sildenafil to prevent bronchopulmonary dysplasia: A systematic review and meta-analysis

BACKGROUND

Bronchopulmonary dysplasia (BPD) persists as one of the foremost factors contributing to mortality and morbidity in extremely preterm infants. The effectiveness of administering sildenafil early on to prevent BPD remains uncertain. The aim of this study was to investigate the efficacy and safety of prophylactically administered sildenafil during the early life stages of preterm infants to prevent mortality and BPD.

METHODS

MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature, and Ichushi were searched. Published randomized controlled trials (RCTs), non-RCTs, interrupted time series, cohort studies, case-control studies, and controlled before-and-after studies were included. Two reviewers independently screened the title, abstract, and full text, extracted data, assessed the risk of bias, and evaluated the certainty of evidence (CoE) following the Grading of Recommendations Assessment and Development and Evaluation approach. The random-effects model was used for a meta-analysis of RCTs.

RESULTS

This review included three RCTs (162 infants). There were no significant differences between the prophylactic sildenafil and placebo groups in mortality (risk ratio [RR]: 1.32; 95% confidence interval [CI]: 0.16-10.75; very low CoE), BPD (RR: 1.20; 95% CI: 0.79-1.83; very low CoE), and all other outcome assessed (all with very low CoE). The sample sizes were less than the optimal sizes for all outcomes assessed, indicating the need for further trials.

CONCLUSIONS

The prophylactic use of sildenafil in individuals at risk of BPD did not indicate any advantageous effects in terms of mortality, BPD, and other outcomes, or increased side effects.

Molsidomine decreases hyperoxia-induced lung injury in neonatal rats

BACKGROUND

The study's objective is to evaluate if Molsidomine (MOL), an anti-oxidant, anti-inflammatory, and anti-apoptotic drug, is effective in treating hyperoxic lung injury (HLI).

METHODS

The study consisted of four groups of neonatal rats characterized as the Control, Control+MOL, HLI, HLI + MOL groups. Near the end of the study, the lung tissue of the rats were evaluated with respect to apoptosis, histopathological damage, anti-oxidant and oxidant capacity as well as degree of inflammation.

RESULTS

Compared to the HLI group, malondialdehyde and total oxidant status levels in lung tissue were notably reduced in the HLI + MOL group. Furthermore, mean superoxide dismutase, glutathione peroxidase, and glutathione activities/levels in lung tissue were significantly higher in the HLI + MOL group as compared to the HLI group. Tumor necrosis factor-α and interleukin-1β elevations associated with hyperoxia were significantly reduced following MOL treatment. Median histopathological damage and mean alveolar macrophage numbers were found to be higher in the HLI and HLI + MOL groups when compared to the Control and Control+MOL groups. Both values were increased in the HLI group when compared to the HLI + MOL group.

CONCLUSIONS

Our research is the first to demonstrate that bronchopulmonary dysplasia may be prevented through the protective characteristics of MOL, an anti-inflammatory, anti-oxidant, and anti-apoptotic drug.

IMPACT

Molsidomine prophylaxis significantly decreased the level of oxidative stress markers. Molsidomine administration restored the activities of antioxidant enzymes. Molsidomine prophylaxis significantly reduced the levels of inflammatory cytokines. Molsidomine may provide a new and promising therapy for BPD in the future. Molsidomine prophylaxis decreased lung damage and macrophage infiltration in the tissue.

Erythromycin Attenuates Hyperoxia Induced Lung Injury by Enhancing GSH Expression and Inhibiting Expression of Inflammatory Cytokines

Introduction: Oxidative stress and inflammation have proven to be key factors contributing to the occurrence of BPD. Erythromycin has been shown to be effective in treating the redox imbalance seen in many non-bacterial infectious chronic inflammatory diseases. Methods: Ninety-six premature rats were randomly divided into air + saline chloride group, air + erythromycin group, hyperoxia + saline chloride group and hyperoxia + erythromycin group. Lung tissue specimens were collected from 8 premature rats in each group on days 1, 7 and 14, respectively. Results: Pulmonary pathological changes in premature rats after hyperoxia exposure were similar to those of BPD. Hyperoxia exposure induced high expression of GSH, TNF-α, and IL-1β. Erythromycin intervention caused a further increase in GSH expression and a decrease in TNF-α and IL-1β expression. Conclusion: GSH, TNF-α and IL-1β are all involved in the development of BPD. Erythromycin may alleviate BPD by enhancing the expression of GSH and inhibiting the release of inflammatory mediators.

Trends in neonatal mortality and morbidity in very-low-birth-weight (VLBW) infants over a decade: Singapore national cohort study

BACKGROUND

Very preterm infants are at risk for neurodevelopmental impairment because of postnatal morbidities. This study aims to (1) compare the outcomes of very-low-birth-weight (VLBW) infants in Singapore during two time periods over a decade; 2) compare performances among Singaporean neonatal intensive care units (NICUs); and 3) compare a Singapore national cohort with one from the Australian and New Zealand Neonatal Network (ANZNN).

METHODS

Singapore national data on VLBW infants born during two periods, 2007-2008 (SG2007, n = 286) and 2015-2017 (SG2017, n = 905) were extracted from patient medical records. The care practices and clinical outcomes among three Singapore NICUs were compared using SG2017 data. Third, using data from the ANZNN2017 annual report, infants with gestational age (GA) ≤29 weeks in SG2017 were compared with their Oceania counterparts.

RESULTS

SG2017 had 9.9% higher usage of antenatal steroids (p < 0.001), 8% better survival for infants ≤26 weeks (p = 0.174), and used 12.7% lesser nonsteroidal anti-inflammatory drugs for patent ductus arteriosus closure (p < 0.001) than those of SG2007 cohort. Rate of late-onset sepsis (LOS) was almost halved (7.4% vs. 14.0%, p < 0.001), and exclusive human milk feeding after discharge increased threefold (p < 0.001). SG2017, in contrast, had a higher rate of chronic lung disease (CLD) (20.0% vs. 15.1%, p = 0.098). Within SG2017, the rates of LOS, CLD, and human milk feeding varied significantly between the three NICUs. When compared with ANZNN2017, SG2017 had significantly lower rates of LOS for infants ≤25 weeks (p = 0.001), less necrotizing enterocolitis for infants ≤27 weeks (p = 0.002), and less CLD across all GA groups.

CONCLUSION

Postnatal morbidities and survival rates for VLBW infants in Singapore have improved over a decade. Outcomes for VLBW infants varied among three Singapore NICUs, which provide a rationale for collaboration to improve clinical quality. The outcomes of Singaporean VLBW infants were comparable to those of their ANZNN counterparts.

Modulation of engineered nanomaterial interactions with organ barriers for enhanced drug transport

The biomedical use of nanoparticles (NPs) has been the focus of intense research for over a decade. As most NPs are explored as carriers to alter the biodistribution, pharmacokinetics and bioavailability of associated drugs, the delivery of these NPs to the tissues of interest remains an important topic. To date, the majority of NP delivery studies have used tumor models as their tool of interest, and the limitations concerning tumor targeting of systemically administered NPs have been well studied. In recent years, the focus has also shifted to other organs, each presenting their own unique delivery challenges to overcome. In this review, we discuss the recent advances in leveraging NPs to overcome four major biological barriers including the lung mucus, the gastrointestinal mucus, the placental barrier, and the blood-brain barrier. We define the specific properties of these biological barriers, discuss the challenges related to NP transport across them, and provide an overview of recent advances in the field. We discuss the strengths and shortcomings of different strategies to facilitate NP transport across the barriers and highlight some key findings that can stimulate further advances in this field.

Glutamine inhibits inflammation, oxidative stress, and apoptosis and ameliorates hyperoxic lung injury

Glutamine (Gln) is the most widely acting and abundant amino acid in the body and has anti-inflammatory properties, regulates body metabolism, and improves immune function. However, the mechanism of Gln's effect on hyperoxic lung injury in neonatal rats is unclear. Therefore, this work focused on examining Gln's function in lung injury of newborn rats mediated by hyperoxia and the underlying mechanism. We examined body mass and ratio of wet-to-dry lung tissue weights of neonatal rats. Hematoxylin and eosin (HE) staining was performed to examine histopathological alterations of lung tissues. In addition, enzyme-linked immunoassay (ELISA) was conducted to measure pro-inflammatory cytokine levels within bronchoalveolar lavage fluid (BALF). Apoptosis of lung tissues was observed using TUNEL assay. Western blotting was performed for detecting endoplasmic reticulum stress (ERS)-associated protein levels. The results showed that Gln promoted body weight gain, significantly reduced pathological damage and oxidative stress in lung tissue, and improved lung function in neonatal rats. Gln reduced pro-inflammatory cytokine release as well as inflammatory cell production in BALF and inhibited apoptosis in lung tissue cells. Furthermore, we found that Gln could downregulate ERS-associated protein levels (GRP78, Caspase-12, CHOP) and inhibit c-Jun N-terminal kinase (JNK) and inositol-requiring enzyme 1 alpha (IRE1α) phosphorylation. These results in an animal model of bronchopulmonary dysplasia (BPD) suggest that Gln may have a therapeutic effect on BPD by reducing lung inflammation, oxidative stress, and apoptosis and improving lung function; its mechanism of action may be related to the inhibition of the IRE1α/JNK pathway.

Development and Validation of a Risk Scoring Tool for Bronchopulmonary Dysplasia in Preterm Infants Based on a Systematic Review and Meta-Analysis

Background: Bronchopulmonary dysplasia (BPD) is the most common serious pulmonary morbidity in preterm infants with high disability and mortality rates. Early identification and treatment of BPD is critical. Objective: This study aimed to develop and validate a risk scoring tool for early identification of preterm infants that are at high-risk for developing BPD. Methods: The derivation cohort was derived from a systematic review and meta-analysis of risk factors for BPD. The statistically significant risk factors with their corresponding odds ratios were utilized to construct a logistic regression risk prediction model. By scoring the weights of each risk factor, a risk scoring tool was established and the risk stratification was divided. External verification was carried out by a validation cohort from China. Results: Approximately 83,034 preterm infants with gestational age < 32 weeks and/or birth weight < 1500 g were screened in this meta-analysis, and the cumulative incidence of BPD was about 30.37%. The nine predictors of this model were Chorioamnionitis, Gestational age, Birth weight, Sex, Small for gestational age, 5 min Apgar score, Delivery room intubation, and Surfactant and Respiratory distress syndrome. Based on the weight of each risk factor, we translated it into a simple clinical scoring tool with a total score ranging from 0 to 64. External validation showed that the tool had good discrimination, the area under the curve was 0.907, and that the Hosmer-Lemeshow test showed a good fit (p = 0.3572). In addition, the results of the calibration curve and decision curve analysis suggested that the tool showed significant conformity and net benefit. When the optimal cut-off value was 25.5, the sensitivity and specificity were 0.897 and 0.873, respectively. The resulting risk scoring tool classified the population of preterm infants into low-risk, low-intermediate, high-intermediate, and high-risk groups. This BPD risk scoring tool is suitable for preterm infants with gestational age < 32 weeks and/or birth weight < 1500 g. Conclusions: An effective risk prediction scoring tool based on a systematic review and meta-analysis was developed and validated. This simple tool may play an important role in establishing a screening strategy for BPD in preterm infants and potentially guide early intervention.

Complex roles of TGF-β signaling pathways in lung development and bronchopulmonary dysplasia

As survival of extremely preterm infants continues to improve, there is also an associated increase in bronchopulmonary dysplasia (BPD), one of the most significant complications of preterm birth. BPD development is multifactorial resulting from exposure to multiple antenatal and postnatal stressors. BPD has both short-term health implications and long-term sequelae including increased respiratory, cardiovascular, and neurological morbidity. Transforming growth factor β (TGF-β) is an important signaling pathway in lung development, organ injury, and fibrosis and is implicated in the development of BPD. This review provides a detailed account on the role of TGF-β in antenatal and postnatal lung development, the effect of known risk factors for BPD on the TGF-β signaling pathway, and how medications currently in use or under development, for the prevention or treatment of BPD, affect TGF-β signaling.

Prematurity and BPD: what general pediatricians should know

More and more very low birth weight (VLBW) infants around the world survive nowadays, with consequently larger numbers of children developing prematurity-related morbidities, especially bronchopulmonary dysplasia (BPD). BPD is a multifactorial disease and its rising incidence in recent years means that general pediatricians are much more likely to encounter a child born extremely preterm, possibly with BPD, in their clinical practice. Short- and long-term sequelae in VLBW patients may affect not only pulmonary function (principally characterized by an obstructive pattern), but also other aspect including the neurological (neurodevelopmental and neuropsychiatric disorders), the sensorial (earing and visual impairment), the cardiological (systemic and pulmonary hypertension, reduced exercise tolerance and ischemic heart disease in adult age), nutritional (feeding difficulties and nutritional deficits), and auxological (extrauterine growth restriction). For the most premature infants at least, a multidisciplinary follow-up is warranted after discharge from the neonatal intensive care unit in order to optimize their respiratory and neurocognitive potential, and prevent respiratory infections, nutritional deficiencies or cardiovascular impairments.  Conclusion: The aim of this review is to summarize the main characteristics of preterm and BPD infants, providing the general pediatrician with practical information regarding these patients' multidisciplinary complex follow-up. We explore the current evidence on respiratory outcomes and their management that actually does not have a definitive available option. We also discuss the available investigations, treatments, and strategies for prevention and prophylaxis to improve the non-respiratory outcomes and the quality of life for these children and their families, a critical aspect not always considered. This comprehensive approach, added to the increased needs of a VLBW subjects, is obviously related to very high health-related costs that should be beared in mind. What is Known: • Every day, a general pediatrician is more likely to encounter a former very low birth weight infant. • Very low birth weight and prematurity are frequently related not only with worse respiratory outcomes, but also with neurological, sensorial, cardiovascular, renal, and nutritional issues. What is New: • This review provides to the general pediatrician a comprehensive approach for the follow-up of former premature very low birth weight children, with information to improve the quality of life of this special population.

Molecular mechanisms of cell death in bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) in neonates is the most common pulmonary disease that causes neonatal mortality, has complex pathogenesis, and lacks effective treatment. It is associated with chronic obstructive pulmonary disease, pulmonary hypertension, and right ventricular hypertrophy. The occurrence and development of BPD involve various factors, of which premature birth is the most crucial reason for BPD. Under the premise of abnormal lung structure and functional product, newborns are susceptible to damage to oxides, free radicals, hypoxia, infections and so on. The most influential is oxidative stress, which induces cell death in different ways when the oxidative stress balance in the body is disrupted. Increasing evidence has shown that programmed cell death (PCD), including apoptosis, necrosis, autophagy, and ferroptosis, plays a significant role in the molecular and biological mechanisms of BPD and the further development of the disease. Understanding the mode of PCD and its signaling pathways can provide new therapeutic approaches and targets for the clinical treatment of BPD. This review elucidates the mechanism of BPD, focusing on the multiple types of PCD in BPD and their molecular mechanisms, which are mainly based on experimental results obtained in rodents.

MSC-EXO and tempol ameliorate bronchopulmonary dysplasia in newborn rats by activating HIF-1α

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a major complication of premature infants and an important cause of morbidity and mortality. This study investigates the effect of the combination of mesenchymal stem cells-derived exosomes (MSC-EXO) and tempol on BPD and analyzes its mechanism.

METHODS

MSC-EXO was extracted by centrifugation and identified by transmission electron microscopy (TEM), nanoparticle tracking analysis, and western blot analysis (WB). Tidal volume (TV), minute ventilation (MV), peak inspiratory flow (PIF), and dynamic pulmonary compliance (Cdyn) of rats were measured by BuxCo pulmonary function experimental platform. Hematoxylin-eosin staining was performed to observe the lung morphology and radical alveolar count (RAC) and mean linear intercept (MLI) were assessed. Immunofluorescence (IF) was conducted to detect the expression of CD31 and α-SMA in pulmonary blood vessels. The kits were used to calculate malondialdehyde (MDA), superoxide dismutase (SOD), and total antioxidant capacity (TAOC) concentration in lung tissue. Enzyme linked immunosorbent assay was applied to detect the levels of IL-1β, IL-17, IL-6, and IFN-γ in bronchoalveolar lavage fluid. In addition, the expressions of HIF-1α, vascular endothelial growth factor (VEGF), p-PI3K, and p-AKT were analyzed by WB and IF.

RESULTS

We successfully extracted and identified MSC-EXO. In BPD rats, TV, MV, PIF, and Cdyn decreased, alveoli were simplified, and the number of interalveoli small vessels, blood vessel density decreased. Moreover, RAC, CD31, TAOC, and SOD decreased, and MLI, α-SMA, MDA, IL-1β, IL-17, IL-6, and IFN-γ increased, which was reversed by the combination of MSC-EXO and tempol treatment after combined treatment. In addition, the expression levels of HIF-1α, VEGF, p-PI3K, and p-AKT were increased after combined treatment.

CONCLUSIONS

Combined treatment could improve lung tissue injury, promote pulmonary vascular remodeling, restore lung function, and inhibit oxidative stress in BPD rats. These effects were achieved through activation of HIF-1α.

Identification and immunological characterization of endoplasmic reticulum stress-related molecular subtypes in bronchopulmonary dysplasia based on machine learning

Introduction: Bronchopulmonary dysplasia (BPD) is a life-threatening lung illness that affects premature infants and has a high incidence and mortality. Using interpretable machine learning, we aimed to investigate the involvement of endoplasmic reticulum (ER) stress-related genes (ERSGs) in BPD patients. Methods: We evaluated the expression profiles of endoplasmic reticulum stress-related genes and immune features in bronchopulmonary dysplasia using the GSE32472 dataset. The endoplasmic reticulum stress-related gene-based molecular clusters and associated immune cell infiltration were studied using 62 bronchopulmonary dysplasia samples. Cluster-specific differentially expressed genes (DEGs) were identified utilizing the WGCNA technique. The optimum machine model was applied after comparing its performance with that of the generalized linear model, the extreme Gradient Boosting, the support vector machine (SVM) model, and the random forest model. Validation of the prediction efficiency was done by the use of a calibration curve, nomogram, decision curve analysis, and an external data set. Results: The bronchopulmonary dysplasia samples were compared to the control samples, and the dysregulated endoplasmic reticulum stress-related genes and activated immunological responses were analyzed. In bronchopulmonary dysplasia, two distinct molecular clusters associated with endoplasmic reticulum stress were identified. The analysis of immune cell infiltration indicated a considerable difference in levels of immunity between the various clusters. As measured by residual and root mean square error, as well as the area under the curve, the support vector machine machine model showed the greatest discriminative capacity. In the end, an support vector machine model integrating five genes was developed, and its performance was shown to be excellent on an external validation dataset. The effectiveness in predicting bronchopulmonary dysplasia subtypes was further established by decision curves, calibration curves, and nomogram analyses. Conclusion: We developed a potential prediction model to assess the risk of endoplasmic reticulum stress subtypes and the clinical outcomes of bronchopulmonary dysplasia patients, and our work comprehensively revealed the complex association between endoplasmic reticulum stress and bronchopulmonary dysplasia.

Artificial intelligence in bronchopulmonary dysplasia- current research and unexplored frontiers

Provide an overview of bronchopulmonary dysplasia, its definitions, and their shortcomings. Explore the areas where machine learning may be used to further our understanding of bronchopulmonary dysplasia.

Early Biomarkers of Bronchopulmonary Dysplasia: A Quick Look to the State of the Art

Bronchopulmonary dysplasia (BPD) is one of the most common pulmonary sequelae of extreme preterm birth, with long-lasting respiratory symptoms and reduced lung function. A reliable predictive tool of BPD development is urgent and its search remains one of the major challenges for neonatologists approaching the upcoming arrival of possible new preventive therapies. Biomarkers, identifying an ongoing pathogenetic pathway, could allow both the selection of preterm infants with an evolving disease and potentially the therapeutic targets of the indicted pathogenesis. The "omic" sciences represent well-known promising tools for this objective. In this review, we resume the current laboratoristic, metabolomic, proteomic, and microbiomic evidence in the prediction of BPD. KEY POINTS: · The early prediction of BPD development would allow the targeted implementation of new preventive therapies.. · BPD is a multifactorial disease consequently it is unlikely to find a single disease biomarker.. · "Omic" sciences offer a promising insight in BPD pathogenesis and its development's fingerprints..

Extracellular Vesicles: A New Promise for the Prevention of Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) despite numerous efforts of neonatologists remains one of the most frequent and long-lasting chronic respiratory diseases consequent to extreme preterm birth. New clinical trials are exploring the possible use of mesenchymal stem cells (MSCs) and especially their products, extracellular vesicles (EVs), that overcome some of the possible issues related to the use of live cells. MSCs already reached clinical implementation; MSC-EVs, on the contrary, showed extremely promising results in the preclinical setting but are still waiting their first in human results that are likely to happen soon. KEY POINTS: · BPD is one of the most frequent complications of preterm birth, and its prevention lacks an effective tool.. · EVs have shown encouraging results in preclinical animal models.. · Technical and biological advancements are needed before routine clinical use..

Bone mesenchymal stem cell-derived exosomes prevent hyperoxia-induced apoptosis of primary type II alveolar epithelial cells in vitro

Background

The presence of alveolar epithelial type II cells (AECIIs) is one of the most important causes of bronchopulmonary dysplasia (BPD). Exosomes from bone mesenchymal stem cells (BMSCs) can reduce hyperoxia-induced damage and provide better results in terms of alveolar and pulmonary vascularization parameters than BMSCs. Currently, intervention studies using BMSC-derived exosomes on the signaling pathways regulating proliferation and apoptosis of alveolar epithelial cells under the condition of BPD have not been reported. This study investigated the effects of rat BMSC-derived exosomes on the proliferation and apoptosis of hyperoxia-induced primary AECIIs in vitro.

Methods

The isolated AECIIs were grouped as follows: normal control (21% oxygen), hyperoxia (85% oxygen), hyperoxia+exosome (20 µg/mL), hyperoxia+exosome+LY294002 (PI3K/Akt inhibitor, 20 µM), and hyperoxia+exosome+rapamycin (mTOR inhibitor, 5 nM). We used the PI3K/Akt inhibitor LY294002 and the mTOR inhibitor rapamycin to determine the roles of the PI3K/Akt and mTOR signaling pathways. The effects of BMSC-derived exosomes on AECII proliferation and apoptosis were assessed, respectively.

Results

Decreased levels of the antiapoptotic protein Bcl-2, the cell proliferation protein Ki67, p-PI3K, p-Akt, and p-mTOR, as well as increased levels of AECII apoptosis and the proapoptotic protein Bax in the hyperoxia group were observed. Notably, Sprague Dawley rat BMSC-derived exosomes could reverse the effect of hyperoxia on AECII proliferation. However, the application of LY294002 and rapamycin inhibited the protective effects of BMSC-derived exosomes.

Conclusion

Our findings revealed that BMSC-derived exosomes could regulate the expression of apoptosis-related proteins likely via the PI3K/Akt/mTOR signaling pathway, thereby preventing hyperoxia-induced AECII apoptosis.

Bronchopulmonary dysplasia and wnt pathway-associated single nucleotide polymorphisms

AIM

Genetic variants contribute to the pathogenesis of bronchopulmonary dysplasia (BPD). The aim of this study is to evaluate the association of 45 SNPs with BPD susceptibility in a Turkish premature infant cohort.

METHODS

Infants with gestational age &lt;32 weeks were included. Patients were divided into BPD or no-BPD groups according to oxygen need at 28 days of life, and stratified according to the severity of BPD. We genotyped 45 SNPs, previously identified as BPD risk factors, in 192 infants.

RESULTS

A total of eight SNPs were associated with BPD risk at allele level, two of which (rs4883955 on KLF12 and rs9953270 on CHST9) were also associated at the genotype level. Functional relationship maps suggested an interaction between five of these genes, converging on WNT5A, a member of the WNT pathway known to be implicated in BPD pathogenesis. Dysfunctional CHST9 and KLF12 variants may contribute to BPD pathogenesis through an interaction with WNT5A.

CONCLUSIONS

We suggest investigating the role of SNPs on different genes which are in relation with the Wnt pathway in BPD pathogenesis. We identified eight SNPs as risk factors for BPD in this study. In-silico functional maps show an interaction of the genes harboring these SNPs with the WNT pathway, supporting its role in BPD pathogenesis.

TRIAL REGISTRATION

NCT03467828.

IMPACT

It is known that genetic factors may contribute to the development of BPD in preterm infants. Further studies are required to identify specific genes that play a role in the BPD pathway to evaluate them as a target for therapeutic interventions. Our study shows an association of BPD predisposition with certain polymorphisms on MBL2, NFKBIA, CEP170, MAGI2, and VEGFA genes at allele level and polymorphisms on CHST9 and KLF12 genes at both allele and genotype level. In-silico functional mapping shows a functional relationship of these five genes with WNT5A, suggesting that Wnt pathway disruption may play a role in BPD pathogenesis.

Antimicrobial Peptides in Early-Life Host Defense, Perinatal Infections, and Necrotizing Enterocolitis—An Update

Host defense against early-life infections such as chorioamnionitis, neonatal sepsis, or necrotizing enterocolitis (NEC) relies primarily on innate immunity, in which antimicrobial peptides (AMPs) play a major role. AMPs that are important for the fetus and neonate include α and β defensins, cathelicidin LL-37, antiproteases (elafin, SLPI), and hepcidin. They can be produced by the fetus or neonate, the placenta, chorioamniotic membranes, recruited neutrophils, and milk-protein ingestion or proteolysis. They possess antimicrobial, immunomodulating, inflammation-regulating, and tissue-repairing properties. AMPs are expressed as early as the 13th week and increase progressively through gestation. Limited studies are available on AMP expression and levels in the fetus and neonate. Nevertheless, existing evidence supports the role of AMPs in pathogenesis of chorioamnionitis, neonatal sepsis, and NEC, and their association with disease severity. This suggests a potential role of AMPs in diagnosis, prevention, prognosis, and treatment of sepsis and NEC. Herein, we present an overview of the antimicrobial and immunomodulating properties of human AMPs, their sources in the intrauterine environment, fetus, and neonate, and their changes during pre- and post-natal infections and NEC. We also discuss emerging data regarding the potential utility of AMPs in early-life infections, as diagnostic or predictive biomarkers and as therapeutic alternatives or adjuncts to antibiotic therapy considering the increase of antibiotic resistance in neonatal intensive care units.

Nutrition of Infants with Bronchopulmonary Dysplasia before and after Discharge from the Neonatal Intensive Care Unit

Bronchopulmonary dysplasia (BPD) represents a severe sequela in neonates born very prematurely. The provision of adequate nutritional support in this high-risk population is challenging. The development of the lungs and physical growth are closely linked together in infants with BPD. Growth deficiency has been associated with pulmonary dysfunction, whereas improvement in respiratory status results in growth acceleration. Currently, there is not enough data regarding optimal nutritional strategies in this population. Nutrition in these infants should provide sufficient calories and nutrients to establish growth, avoid growth retardation and assist alveolarization of the lungs. Meticulous follow-up is mandatory during and after discharge from the Neonatal Intensive care Unit (NICU) to minimize growth retardation and improve lung function. Despite the significant literature supporting the contribution of growth and nutrition in the avoidance of BPD, there is limited research regarding interventions and management of infants with established BPD. Our aim was to review clinical strategies applied in everyday clinical practice and identify debates on the nutritional approach of newborns with BPD. Well-organized interventions and clinical trials regarding the somatic development and nutrition of infants with BPD are warranted.

Prevalence and Risk Factors for Kidney Disease and Elevated BP in 2-Year-Old Children Born Extremely Premature

BACKGROUND AND OBJECTIVES

Extremely low gestational age neonates born <28 weeks gestation are at risk for chronic disease. We sought to describe the prevalence of kidney outcomes by gestational age and determine risk factors for their development.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Recombinant Erythropoietin for Protection of Infant Renal Disease (REPAIReD) study examined kidney outcomes of extremely low gestational age neonates enrolled in the Preterm Epo NeuroProtection Trial (PENUT) study. Kidney function, urine albumin, and BP were measured at 2-year (24±2 months) corrected gestational age. We compared outcomes across gestational age categories and evaluated associations between kidney-related outcomes and neonatal and maternal characteristics. The primary outcome was eGFR <90 ml/min per 1.73 m² (CKD); secondary outcomes were spot urine albumin-creatinine ratio ≥30 mg/g (albuminuria) and either systolic BP or diastolic BP >90th percentile for height, age, and sex.

RESULTS

A total of 832 survived to 2 years, and 565 (68%) had at least one outcome measured. Overall, 297 (53%) had one abnormal kidney outcome; 61 (18%) had an eGFR <90 ml/min per 1.73 m², 155 (36%) had albuminuria, 65 (22%) had elevated systolic BP, and 128 (44%) had elevated diastolic BP. Gestational age (odds ratio, 0.94; 95% confidence interval, 0.89 to 0.99), birth weight z-score (odds ratio, 0.92; 95% confidence interval, 0.85 to 0.98), and prenatal steroids (odds ratio, 1.23; 95% confidence interval, 1.08 to 1.39) were associated with an eGFR <90 ml/min per 1.73 m². An elevated systolic BP was associated with indomethacin use (odds ratio, 1.18; 95% confidence interval, 1.04 to 1.33) and Black race (odds ratio, 1.19; 95% confidence interval, 1.01 to 1.39); elevated diastolic BP was associated with male sex (odds ratio, 1.29; 95% confidence interval, 1.12 to 1.49), severe AKI (odds ratio, 1.24; 95% confidence interval, 1.04 to 1.48), and indomethacin use (odds ratio, 1.16; 95% confidence interval, 1.01 to 1.33).

CONCLUSIONS

Approximately 18% of extremely low gestational age neonates have CKD, 36% have albuminuria, 22% have an elevated systolic BP, and 44% have an elevated diastolic BP at 2 years of age. Gestational age, birthweight z-score, and prenatal steroids were associated with CKD. Male sex, Black race, indomethacin use, and severe AKI were associated with elevated BP.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2022_07_19_CJN15011121.mp3.

National multi-centre study found a low prevalence of severely impaired lung function in children and adolescents

AIM

As no data to our knowledge exist, the aim of the study was to describe the national prevalence and characteristics of Danish children and adolescents with severely impaired lung function.

METHODS

We performed a descriptive, cross-sectional Danish multi-centre study. Children and adolescents between 6 and 18 years old demonstrating severely impaired lung function from 2015 to 2018, defined by forced expiratory volume in 1 second (FEV₁ ) <60% or who had lung transplantation, were eligible for inclusion.

RESULTS

This study included 113 children with a mean age (standard deviation) of 12.9 years (3.5 years). The prevalence of severely impaired lung function was approximately 13 in 100,000. The mean (standard deviation) FEV₁ was 46.1% (10.1%) of predicted, and z-score was -4.5 (0.8). The most frequent diagnosis was cystic fibrosis (20.4%), followed by asthma (19.5%) and bronchiolitis obliterans (16.8%), while almost 25% had different elements of airway malformations or non-pulmonary conditions. Two adolescents with cystic fibrosis underwent lung transplantation.

CONCLUSION

The estimated prevalence of severely impaired lung function in Danish children and adolescents was low, and extremely, few children underwent lung transplantation. The most frequent diagnosis was cystic fibrosis, while almost 25% had different elements of airway malformations or non-pulmonary conditions, which may require clinical attention.

HLA-A2 Promotes the Therapeutic Effect of Umbilical Cord Blood-Derived Mesenchymal Stem Cells in Hyperoxic Lung Injury

Mesenchymal stem cells (MSCs) are one of the most extensively studied stem cell types owing to their capacity for differentiation into multiple lineages as well as their ability to secrete regenerative factors and modulate immune functions. However, issues remain regarding their further application for cell therapy. Here, to demonstrate the superiority of the improvement of MSCs, we divided umbilical cord blood-derived MSCs (UCB-MSCs) from 15 donors into two groups based on efficacy and revealed donor-dependent variations in the anti-inflammatory effect of MSCs on macrophages as well as their immunoregulatory effect on T cells. Through surface marker analyses (242 antibodies), we found that HLA-A2 was positively related to the anti-inflammatory and immunoregulatory function of MSCs. Additionally, HLA-A2 mRNA silencing in MSCs attenuated their therapeutic effects in vitro; namely, the suppression of LPS-stimulated macrophages and phytohemagglutinin-stimulated T cells. Moreover, HLA-A2 silencing in MSCs significantly decreased their therapeutic effects in a rat model of hyperoxic lung damage. The present study provides novel insights into the quality control of donor-derived MSCs for the treatment of inflammatory conditions and diseases.

Stem-Cell Therapy for Bronchopulmonary Dysplasia (BPD) in Newborns

Premature newborns are at a higher risk for the development of respiratory distress syndrome (RDS), acute lung injury (ALI) associated with lung inflammation, disruption of alveolar structure, impaired alveolar growth, lung fibrosis, impaired lung angiogenesis, and development of bronchopulmonary dysplasia (BPD) with severe long-term developmental adverse effects. The current therapy for BPD is limited to supportive care including high-oxygen therapy and pharmacotherapy. Recognizing more feasible treatment options to improve lung health and reduce complications associated with BPD is essential for improving the overall quality of life of premature infants. There is a reduction in the resident stem cells in lungs of premature infants with BPD, which strongly suggests a critical role of stem cells in BPD pathogenesis; this warrants the exploration of the potential therapeutic use of stem-cell therapy. Stem-cell-based therapies have shown promise for the treatment of many pathological conditions including acute lung injury and BPD. Mesenchymal stem cells (MSCs) and MSC-derived extracellular vesicles (EVs) including exosomes are promising and effective therapeutic modalities for the treatment of BPD. Treatment with MSCs and EVs may help to reduce lung inflammation, improve pulmonary architecture, attenuate pulmonary fibrosis, and increase the survival rate.

Bronchopulmonary dysplasia from chest radiographs to magnetic resonance imaging and computed tomography: adding value

Bronchopulmonary dysplasia (BPD) is a common long-term complication of preterm birth. The chest radiograph appearance and survivability have evolved since the first description of BPD in 1967 because of improved ventilation and clinical strategies and the introduction of surfactant in the early 1990s. Contemporary imaging care is evolving with the recognition that comorbidities of tracheobronchomalacia and pulmonary hypertension have a great influence on outcomes and can be noninvasively evaluated with CT and MRI techniques, which provide a detailed evaluation of the lungs, trachea and to a lesser degree the heart. However, echocardiography remains the primary modality to evaluate and screen for pulmonary hypertension. This review is intended to highlight the important findings that chest radiograph, CT and MRI can contribute to precision diagnosis, phenotyping and prognosis resulting in optimal management and therapeutics.

Evaluation of Trends in Bronchopulmonary Dysplasia and Respiratory Support Practice for Very Low Birth Weight Infants: A Population-Based Cohort Study

OBJECTIVES

To characterize the incidence of bronchopulmonary dysplasia (BPD) over time and to test the association of multilevel factors, including respiratory support, with the diagnosis of BPD.

STUDY DESIGN

This population-based cohort study included 40 268 infants born between 22 and 32 weeks of gestation at hospitals in California between 2008 and 2017. The diagnosis of BPD was based on respiratory support at 36 weeks postmenstrual age. Tests for linear trend and multivariable logistic regression analyses were performed.

RESULTS

The rate of BPD was consistent year to year, and the mortality rate declined. The incidence of BPD was 23.5% for the overall cohort, 44.9% for infants born at <28 weeks of gestational age, and 45.2% for extremely low birth weight infants. For infants born at >26 weeks of gestational age, the incidence of BPD was significantly decreased in the most recent 3-year period compared with the earlier 3 years (OR, 0.91). Invasive ventilation during delivery room resuscitation (OR, 2.64) and after leaving the delivery room (OR, 10.02) conferred the highest risk of BPD compared with oxygen or no respiratory support. Noninvasive ventilation as maximum respiratory support at 36 weeks increased by 20% over time.

CONCLUSIONS

Marked changes in noninvasive support care have occurred without an overall decline in BPD rate. Further research, quality improvement, and strategies, along with noninvasive respiratory support, are needed for a reduction in the incidence of BPD.

Corticosteroids in the prevention and treatment of infants with bronchopulmonary dysplasia: Part II. Inhaled corticosteroids alone or in combination with surfactants

This paper is the second in a two-part State-of-the-Art series that reviews the latest relevant clinical trials investigating the short-term and long-term effects of corticosteroids in the prevention and treatment of bronchopulmonary dysplasia (BPD). Inhaled postnatal corticosteroids demonstrate low systemic bioavailability and rapid systemic clearance with high pulmonary deposition and were expected to reduce the incidence of BPD with reduced adverse effects, however, increased rate of mortality in the neonatal period and at the 18-24 months follow-up was observed. In a milestone study, intratracheal instillation of corticosteroids combined with surfactant decreased the incidence of BPD without increasing the mortality or the long-term neurodevelopmental adverse outcomes. However, subsequent trials using different types of surfactants, different surfactant to budesonide ratio, different time of the drug administration for infants with different severity of respiratory distress syndrome could not reproduce all the beneficial effects. Future perspectives for the identification of premature infants at high risk of BPD and the prevention or treatment of established BPD are discussed.

Hyperoxia Induces Ferroptosis and Impairs Lung Development in Neonatal Mice

Oxygen is often required to treat newborns with respiratory disorders, and prolonged exposure to high oxygen concentrations impairs lung development. Ferroptosis plays a vital role in the development of many diseases and has become the focus of treatment and prognosis improvement for related diseases, such as neurological diseases, infections, cancers, and ischemia-reperfusion injury. Whether ferroptosis participates in the pathogenesis of hyperoxia-induced lung injury remains unknown. The aims of this study are to determine the effects of hyperoxia on lung ferroptosis and development in neonatal mice. Newborn C57BL/6 mice were reared in either room air (RA) or hyperoxia (85% O₂) at postnatal days 1–7. On postnatal days 3 and 7, the lungs were harvested for histological and biochemical analysis. The mice reared in hyperoxia exhibited significantly higher Fe²⁺, malondialdehyde, and iron deposition and significantly lower glutathione, glutathione peroxidase 4, and vascular density than did those reared in RA on postnatal days 3 and 7. The mice reared in hyperoxia exhibited a comparable mean linear intercept on postnatal day 3 and a significantly higher mean linear intercept than the mice reared in RA on postnatal day 7. These findings demonstrate that ferroptosis was induced at a time point preceding impaired lung development, adding credence to the hypothesis that ferroptosis is involved in the pathogenesis of hyperoxia-induced lung injury and suggest that ferroptosis inhibitors might attenuate hyperoxia-induced lung injury.