Influence of bronchopulmonary dysplasia on lung function in adolescents who were born extremely prematurely

Bioinformatic analysis reveals the relationship between macrophage infiltration and Cybb downregulation in hyperoxia-induced bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the most common sequela of prematurity and is characterized by alveolar simplification and lung angiogenesis failure. The aim of this study was to explore the immune signatures of BPD. Differentially expressed gene analysis and immune infiltration analysis were conducted to identify key immune cell types and related genes by using the mRNA-seq dataset GSE25286. The expression patterns of key genes were validated in the scRNA-seq dataset GSE209664 and in experiments. The cell-cell crosstalk of key immune cells was explored with CellChat. We found that differentially expressed genes between BPD mice and controls were mostly enriched in leukocyte migration and M1 macrophages were highly enriched in BPD lungs. Hub genes (Cybb, Papss2, F7 and Fpr2) were validated at the single-cell level, among which the downregulation of Cybb was most closely related to macrophage infiltration. The reduced mRNA and protein levels of Cybb were further validated in animal experiments. Colocalization analysis of Cybb and macrophage markers demonstrated a significant decrease of Cybb in M1 macrophages. Cell-cell crosstalk found that alveolar epithelial cells interacted actively with macrophages through MIF-(CD74 + CD44) signalling. In conclusion, M1 macrophages played important roles in promoting BPD-like lung injury, which was correlated with a specific reduction of Cybb in macrophages and the potential activation of MIF signalling.

Prophylactic early low-dose hydrocortisone and survival without bronchopulmonary dysplasia among extremely preterm infants born at 22-27 weeks' gestation

OBJECTIVE

To compare survival without BPD among extremely preterm infants (EPI) who received prophylactic early low-dose hydrocortisone (PEH) with those who did not (non-PEH).

STUDY DESIGN

This single-center retrospective study compared risk-adjusted rates of survival without BPD, BPD, bowel perforation, and late-onset sepsis among infants (22-27 weeks' gestation at birth) who received PEH (n = 82) and who did not (n = 205).

RESULTS

Infants in the PEH group were of lower gestational age, lower birthweight, and higher day-1 risk of death/BPD. After adjusting for risk of death/BPD, PEH-treated infants demonstrated increased survival without BPD (aOR 2.04, 95%CI 1.1-3.7), and lower BPD rates (aOR 0.46, 95%CI 0.25-0.87). Importantly, bowel perforation or sepsis rate were similar among both groups.

CONCLUSION

After risk adjustment, PEH-treated infants demonstrated improved survival without BPD and did not increase rates of bowel perforation or sepsis. In our cohort of infants, PEH was safe and effective among the sickest preterm neonates.

Cellular Senescence Contributes to the Progression of Hyperoxic Bronchopulmonary Dysplasia

Oxidative stress, inflammation, and endoplasmic reticulum (ER) stress sequentially occur in bronchopulmonary dysplasia (BPD), and all result in DNA damage. When DNA damage becomes irreparable, tumor suppressors increase, followed by apoptosis or senescence. Although cellular senescence contributes to wound healing, its persistence inhibits growth. Therefore, we hypothesized that cellular senescence contributes to BPD progression. Human autopsy lungs were obtained. Sprague-Dawley rat pups exposed to 95% oxygen between Postnatal Day 1 (P1) and P10 were used as the BPD phenotype. N-acetyl-lysyltyrosylcysteine-amide (KYC), tauroursodeoxycholic acid (TUDCA), and Foxo4 dri were administered intraperitoneally to mitigate myeloperoxidase oxidant generation, ER stress, and cellular senescence, respectively. Lungs were examined by histology, transcriptomics, and immunoblotting. Cellular senescence increased in rat and human BPD lungs, as evidenced by increased oxidative DNA damage, tumor suppressors, GL-13 stain, and inflammatory cytokines with decreased cell proliferation and lamin B expression. Cellular senescence-related transcripts in BPD rat lungs were enriched at P10 and P21. Single-cell RNA sequencing showed increased cellular senescence in several cell types, including type 2 alveolar cells. In addition, Foxo4-p53 binding increased in BPD rat lungs. Daily TUDCA or KYC, administered intraperitoneally, effectively decreased cellular senescence, improved alveolar complexity, and partially maintained the numbers of type 2 alveolar cells. Foxo4 dri administered at P4, P6, P8, and P10 led to outcomes similar to TUDCA and KYC. Our data suggest that cellular senescence plays an essential role in BPD after initial inducement by hyperoxia. Reducing myeloperoxidase toxic oxidant production, ER stress, and attenuating cellular senescence are potential therapeutic strategies for halting BPD progression.

An Update on Lung Function of Extremely and Very Preterm Infants in Later Life: The Role of Early Nutritional Interventions

Birth occurring at ≤32 weeks' gestation ("very preterm") or at ≤28 weeks' gestation ("extremely preterm") potentially poses considerable health problems for the neonate, including respiratory sequelae, not only during the immediate newborn period, but throughout childhood and into adulthood. With the progressive improvements in neonatal care, the survival of extremely preterm and very preterm neonates has improved substantially. However, a considerable percentage of these infants suffer dysfunctions that may trigger, at some stage later in life, the onset of respiratory morbidities. The interruption of the normal development of the respiratory tract caused by preterm birth, in combination with postnatal lung injury caused by various interventions, e.g., mechanical ventilation and oxygen therapy, increases the risk ofthe development of long-term respiratory deficits in survivors. Those infants that are most affected are those who develop chronic lung disease of prematurity (also called bronchopulmonary dysplasia, BPD), but impaired lung function can develop irrespective of BPD diagnosis. Apart from indicating abnormal lung function in survivors of extreme prematurity, recent long-term follow-up studies also emphasize the crucial role of early nutritional intake as an effective strategy, which promotes lung growth and repair. This article will update the associations between extremely/very preterm birth with long-term respiratory outcomes. It will also discuss the protective effect of nutritional interventions, focusing on recently published follow-up data.

Respiratory and non-respiratory outcomes of bronchopulmonary dysplasia in adolescents: A systematic review

BACKGROUND

There is lack of evidence synthesis on the global consequences of bronchopulmonary dysplasia (BPD) in adolescence.

AIM

Assess the impact of bronchopulmonary dysplasia on respiratory and non-respiratory outcomes in adolescents.

METHODS

A systematic review of studies assessing the outcomes of adolescents aged 10 to 19 years-old with BPD was conducted. We independently screened studies published until 6th March 2023 in PubMed® and Scopus® databases. Data on methodologic design, sample descriptive and findings were extracted from each study. Risk of bias was assessed using quality assessment tools.

RESULTS

Thirty-one studies were included. Adolescents with a history of BPD present with more respiratory symptoms (wheezing, respiratory exacerbations, need for respiratory medication) and twenty-five studies showed a reduction in pulmonary function, with varying impact according to BPD severity and no differences before and after the surfactant era. Spirometry evaluation throughout the years is not consensual, but methacholine and salbutamol response in BPD groups is increased compared to non-BPD groups. Markers of eosinophilic airway inflammation are not increased as in asthma patients. Exercise potential is identical, but data regarding physical capacity and activity are inconsistent. More frequent radiologic abnormalities translate into higher high-resolution computed tomography scores, with linear (72.2 %) and triangular subpleural opacities (58.3 %) as the most common findings. There is a higher risk for special needs in education, but quality of life seems to be equal to non-BPD adolescents.

CONCLUSIONS

BPD negatively impacts both pulmonary and non-pulmonary outcomes in adolescents.

The prevention and management strategies for neonatal chronic lung disease

INTRODUCTION

Survival from even very premature birth is improving, but long-term respiratory morbidity following neonatal chronic lung disease (bronchopulmonary dysplasia (BPD)) has not reduced. Affected infants may require supplementary oxygen at home, because they have more hospital admissions particularly due to viral infections and frequent, troublesome respiratory symptoms requiring treatment. Furthermore, adolescents and adults who had BPD have poorer lung function and exercise capacity.

AREAS COVERED

Antenatal and postnatal preventative strategies and management of infants with BPD. A literature review was undertaken using PubMed and Web of Science.

EXPERT OPINION

There are effective preventative strategies which include caffeine, postnatal corticosteroids, vitamin A, and volume guarantee ventilation. Side-effects, however, have appropriately caused clinicians to reduce use of systemically administered corticosteroids to infants only at risk of severe BPD. Promising preventative strategies which need further research are surfactant with budesonide, less invasive surfactant administration (LISA), neurally adjusted ventilatory assist (NAVA) and stem cells. The management of infants with established BPD is under-researched and should include identifying the optimum form of respiratory support on the neonatal unit and at home and which infants will most benefit in the long term from pulmonary vasodilators, diuretics, and bronchodilators.