Hospitalization costs associated with bronchopulmonary dysplasia in the first year of life

Changes in Patent Ductus Arteriosus Management and Outcomes in Infants Born at 26-28 Weeks' Gestation

OBJECTIVE

To investigate the association between the secular decrease in treatment of patent ductus arteriosus (PDA) and trends in neonatal mortality and morbidity in infants born at 26 0/7-28 6/7 weeks' gestation.

STUDY DESIGN

A retrospective cohort study including infants born between 2012 and 2021 in continually participating hospitals in the National Institute of Child Health and Human Development Neonatal Research Network. The primary composite outcome was defined as surgical necrotizing enterocolitis, grade 2-3 bronchopulmonary dysplasia (BPD), severe intraventricular hemorrhage, or death. Relationships of temporal trends in PDA treatment with the primary composite outcome and its components were analyzed using a multilevel model accounting for patient-level factors. A separate analysis assessed these relationships stratified by hospital changes in PDA treatment.

RESULTS

The study included 7864 infants. There was a decrease in any PDA treatment from 21% to 16% (P < .01) and an increase in the primary composite outcome from 24% to 36% (P < .01). Change in the primary outcome was driven by increased grade 2-3 BPD (13%-26%, P < .01), with grade 2 BPD accounting for most of this increase (10%-22%, P < .01). Temporal decreases in PDA treatment were associated with increases in the primary outcome and grade 2-3 BPD after adjusting for patient-level factors (P < .01). However, stratified analyses showed that grade 2-3 BPD increased in all hospital groups, regardless of changes in PDA management.

CONCLUSIONS

From 2012 to 2021, temporal decreases in PDA treatment for infants 26-28 weeks were associated with an increase in grade 2-3 BPD. However, caution is warranted in determining causality. Reasons for increased grade 2-3 BPD during the past decade warrant investigation.

TRIAL REGISTRATION

Generic Database: NCT00063063.

L-Citrulline in Neonates: From Bench to Bed Side

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

Association of TNF-α genetic variants with neonatal bronchopulmonary dysplasia: consolidated results

Objectives

Inflammation is increasingly recognized as a key factor in the pathophysiology of bronchopulmonary dysplasia (BPD). While previous research has established significant links between TNF-α polymorphisms and BPD susceptibility, further validation of these associations is needed. This study aims to examine the relationship between TNF-α polymorphisms and the risk of BPD.

Methods

All relevant articles published before October 1, 2024, have been screened in the PubMed, Web of Science, CNKI, and Scopus databases.

Results

A total of 14 case-control studies were conducted: five studies with 1,252 cases and 1,377 controls on -308G/A, three studies with 1,180 cases and 1,194 controls on -238G/A, four studies with 149 cases and 192 controls on -857C/T, and two studies with 82 cases and 162 controls on 1,031 T/C. A significant association was found between the TNF-α -238G/A polymorphism and the risk of BPD. However, no significant relationships were observed for the TNF-α -308G/A, -857C/T, and 1,031 T/C polymorphisms regarding BPD susceptibility.

Conclusions

Our findings indicate a significant association between the TNF-α -238G/A polymorphism and the susceptibility to BPD in preterm neonates, suggesting potential biomarkers for its pathogenesis. However, this meta-analysis has limitations, including possible publication bias and heterogeneity due to the limited number of studies, which may affect the reliability of our conclusions. Moreover, population variability further complicates the interpretation of the link between TNF-α polymorphisms and BPD risk.

Finding treasure in the journey: a single center quality improvement bundle to reduce bronchopulmonary dysplasia

BACKGROUND

Reducing bronchopulmonary dysplasia (BPD) utilizing a single intervention has been challenging. The quality improvement (QI) bundle approach may better address BPD multifactorial risk factors.

METHODS

A single-center interdisciplinary quality improvement (QI) initiative to enhance respiratory care for preterm infants born less than 30 weeks gestation.

GLOBAL AIM

To reduce BPD in preterm infants.

SMART AIM

Introduce and implement a comprehensive, evidence-based respiratory care bundle within 12 months, targeting areas needing improvement in our practices.

RESULTS

Our preplanned improvement targets were achieved for all process measures. Overall BPD incidence did not change (45% vs. 44.3%). After the QI intervention, inborn infants had a lower BPD rate, though not statistically significant (38.7% vs. 30.3%, p = 0.22), with a significant reduction in grade 1 BPD (24.5% vs. 12.4%, p = 0.032).

CONCLUSION

Structured interdisciplinary QI work tailored to local settings can improve respiratory care and possibly amend the outcomes of infants at risk for BPD.

Blocking IL-17a Signaling Decreases Lung Inflammation and Improves Alveolarization in Experimental Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is the most common chronic lung disease of preterm infants that is associated with life-long morbidities. Inflammatory insults contribute to BPD pathogenesis. Although the proinflammatory cytokine, IL-17a, plays a role in various neonatal inflammatory disorders, its role in BPD pathogenesis is unclear. To test the hypothesis that blocking IL-17a signaling decreases lipopolysaccharide (LPS)-mediated experimental BPD in neonatal mice, wild-type mice were injected intraperitoneally with phosphate-buffered saline or LPS during the saccular lung developmental phase. Pulmonary IL-17a expression was determined by enzyme-linked immunosorbent assay and by flow cytometry. LPS-injected mice had higher pulmonary IL-17a protein levels and IL-17a+ and IL-22+ cells. γδ T cells, followed by non-T lymphoid cells, were the primary producers of IL-17a. Wild-type mice were then injected intraperitoneally with isotype antibody (Ab) or IL-17a Ab, while they were treated with phosphate-buffered saline or LPS, followed by quantification of lung inflammatory markers, alveolarization, vascularization, cell proliferation, and apoptosis. LPS-mediated alveolar simplification, apoptosis, and cell proliferation inhibition were significantly greater in mice treated with isotype Ab than in those treated with IL-17a Ab. Furthermore, STAT1 activation and IL-6 levels were significantly greater in LPS-exposed mice treated with isotype Ab than in those treated with IL-17a Ab. The study results indicate that blocking IL-17a signaling decreases LPS-mediated experimental BPD.

The emerging roles of microbiome and short-chain fatty acids in the pathogenesis of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease that affects premature infants and leads to long-term pulmonary complications. The pathogenesis of BPD has not been fully elucidated yet. In recent years, the microbiome and its metabolites, especially short-chain fatty acids (SCFAs), in the gut and lungs have been demonstrated to be involved in the development and progression of the disease. This review aims to summarize the current knowledge on the potential involvement of the microbiome and SCFAs, especially the latter, in the development and progression of BPD. First, we introduce the gut-lung axis, the production and functions of SCFAs, and the role of SCFAs in lung health and diseases. We then discuss the evidence supporting the involvement of the microbiome and SCFAs in BPD. Finally, we elaborate on the potential mechanisms of the microbiome and SCFAs in BPD, including immune modulation, epigenetic regulation, enhancement of barrier function, and modulation of surfactant production and the gut microbiome. This review could advance our understanding of the microbiome and SCFAs in the pathogenesis of BPD, which also helps identify new therapeutic targets and facilitate new drug development.

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.

Discharge preparation experiences and needs of intergenerational caregivers of neonatal intensive care unit preterm: A qualitative study

PURPOSE

This study aimed to explore the real experiences and needs of neonatal intensive care unit (NICU) preterm intergenerational caregivers for discharge preparation and provide a basis for nursing staff to formulate systemic and personalized health education plans and continuous nursing plans for preterm discharge.

DESIGN AND METHODS

This was a descriptive qualitative study. An objective sampling method was used to select 16 intergenerational caregivers of preterm infants admitted to the NICU of tertiary obstetrics and gynecology hospitals in Zhejiang and Jilin provinces from December 2023 to February 2024. Semi-structured interviews were conducted on the day of discharge of the preterm infants and six weeks after discharge. Colaizzi's seven-step analysis method was used to analyze the interview data.

RESULTS

Based on the existence, relatedness, and growth (ERG) theory, the discharge preparation experiences and needs of neonatal intergenerational caregivers in the NICU were summarized into three themes: psychological condition, care capacity condition, and multi-party support needs.

CONCLUSIONS

In the process of hospital discharge preparation, intergenerational caregivers of premature infants in NICU have multiple needs, including enhancing nursing ability and obtaining psychological and multi-party support. It is helpful to take effective interventions to improve their readiness for discharge.

PRACTICE IMPLICATIONS

The nursing staff should develop personalized discharge health education plans and continuous nursing plans to improve the level of discharge preparation.

PATIENT OR PUBLIC CONTRIBUTIONS

There were no patient or public contributions.

miRNA Signatures in Bronchopulmonary Dysplasia: Implications for Biomarkers, Pathogenesis, and Therapeutic Options

Bronchopulmonary dysplasia (BPD) is a chronic lung disease in premature infants characterized by alveolar dysplasia, vascular simplification and dysmorphic vascular development. Supplemental oxygen and mechanical ventilation commonly used as life-saving measures in premature infants may cause BPD. microRNAs (miRNAs), a class of small, non-coding RNAs, regulate target gene expression mainly through post-transcriptional repression. miRNAs play important roles in modulating oxidative stress, proliferation, apoptosis, senescence, inflammatory responses, and angiogenesis. These cellular processes play pivotal roles in the pathogenesis of BPD. Accumulating evidence demonstrates that miRNAs are dysregulated in the lung of premature infants with BPD, and in animal models of this disease, suggesting contributing roles of dysregulated miRNAs in the development of BPD. Therefore, miRNAs are considered promising biomarker candidates and therapeutic agents for this disease. In this review, we discuss how dysregulated miRNAs and their modulation alter cellular processes involved in BPD. We then focus on therapeutic approaches targeting miRNAs for BPD. This review provides an overview of miRNAs as biomarkers, and highlights potential pathogenic roles, and therapeutic strategies for BPD using miRNAs.

An epidemiological investigation of high-risk infants for Respiratory Syncytial Virus infections: a retrospective cohort study

BACKGROUND

Respiratory Syncytial Virus (RSV) infections may lead to severe consequences in infants born preterm with breathing problems (such as bronchopulmonary dysplasia (BPD) and respiratory distress syndrome (RDS)) or congenital heart diseases (CHD). Since studies investigating the influence of different gestational age (WGA) and concomitant specific comorbidities on the burden of RSV infections are scarce, the present study aimed to better characterize these high-risk populations in the Italian context.

METHODS

This retrospective, longitudinal and record-linkage cohort study involved infants born between 2017 and 2019 in Lazio Region (Italy) and is based on data extracted from administrative databases. Each infant was exclusively included in one of the following cohorts: (1) BPD-RDS (WGA ≤35 with or without CHD) or (2) CHD (without BPD and/or RDS) or (3) Preterm (WGA ≤35 without BPD (and/or RDS) or CHD). Each cohort was followed for 12 months from birth. Information related to sociodemographic at birth, and RSV and Undetermined Respiratory Agents (URA) hospitalizations and drug consumption at follow-up were retrieved and described.

RESULTS

A total of 8,196 infants were selected and classified as 1,084 BPD-RDS, 3,286 CHD and 3,826 Preterm. More than 30% of the BPD-RDS cohort was composed by early preterm infants (WGA ≤ 29) in contrast to the Preterm cohort predominantly constitute by moderate preterm infants (98.2%), while CHD infants were primarily born at term (83.9%). At follow-up, despite the cohorts showed similar proportions of RSV hospitalizations, in BPD-RDS cohort hospitalizations were more frequently severe compared to those occurred in the Preterm cohort (p<0.01), in the BPD-RDS cohort was also found the highest proportion of URA hospitalizations (p<0.0001). In addition, BPD-RDS infants, compared to those of the remaining cohorts, received more frequently prophylaxis with palivizumab (p<0.0001) and were more frequently treated with adrenergics inhalants, and glucocorticoids for systemic use.

CONCLUSIONS

The assessment of the study clinical outcomes highlighted that, the demographic and clinical characteristics at birth of the study cohorts influence their level of vulnerability to RSV and URA infections. As such, continuous monitoring of these populations is necessary in order to ensure a timely organization of health care system able to respond to their needs in the future.

Risk Prediction of Severe Bronchopulmonary Dysplasia (BPD) Using the Respiratory Severity Score (RSS) in Extremely Preterm Infants: A Retrospective Study From Saudi Arabia

Background Bronchopulmonary dysplasia (BPD) is a significant complication in extremely preterm infants. Therefore, early diagnosis of BPD is important for planning treatment strategies. In this study, we aimed to assess the predictive efficacy of the Respiratory Severity Score (RSS) in determining severe BPD or death outcomes in very preterm infants. Methodology This retrospective study included preterm infants born with a gestational age of ≤30 weeks. The inclusion criteria comprised individuals who were mechanically ventilated (<1 week) during the first four weeks of life. Any patients who died during the first seven days of life were excluded. RSS values were recorded on days 3, 14, 21, and 28 of life. Multivariate logistic regression was used to identify a correlation between RSS and patient outcomes. Results A total of 154 infants were included in the analysis, of whom 82 (53.24%) developed severe BPD and 38 (24.67%) died. RSS was higher in patients who either died or developed severe BPD compared to those who survived. The multivariate logistic regression analysis revealed that RSSs at postnatal day 14 (odds ratio (OR) = 3.970; 95% confidence interval (CI) = 1.114-14.147; p < 0.05), day 21 (OR = 6.201; 95% CI = 1.937-19.851; p < 0.05), and day 28 (OR = 8.925; 95% CI = 3.331-28.383; p < 0.05) was significantly associated with a higher risk of death or severe BPD. Conclusions The findings of the present study revealed that RSS can help predict the risk of severe BPD in very preterm infants.

Quality, outcome, and cost of care provided to very low birth weight infants in California

OBJECTIVE

To examine association of costs with quality of care and patient outcome across hospitals in California.

METHODS

Retrospective study of very low birth weight (VLBW) births from 2014-2018 linking birth certificate, hospital discharge records and clinical data. Quality was measured using the Baby-MONITOR score. Clinical outcome was measured using survival without major morbidity (SWMM). Hierarchical generalized linear models, adjusting for clinical factors, were used to estimate risk-adjusted measures of costs, quality, and outcome for each hospital. Association between these measures was evaluated using Pearson correlation coefficient.

RESULTS

In total, 15,415 infants from 104 NICUs were included. Risk-adjusted Baby-MONITOR score, SWMM rate, and costs varied substantially. There was no correlation between risk-adjusted cost and Baby-MONITOR score (r = 0, p = 0.998). Correlation between risk-adjusted cost and SWMM rate was inverse and not significant (r = -0.07, p = 0.48).

CONCLUSIONS

With the metrics used, we found no correlation between cost, quality, and outcomes in the care of VLBW infants.

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.

Incremental cost of premature birth - a public health care payer perspective from Hungary

BACKGROUND

Preterm birth remains a significant burden to families, health systems and societies. The aim was to quantify the incremental prematurity-related public health expenditure in Hungary and to estimate the potential impact of a decrease in the prevalence of prematurity on the public payer's spending.

METHODS

Over a 6-year time horizon, public financing data of inpatient, outpatient and pharmaceutical care for children born at ≥ 25 weeks of gestation in 2009/2010 were retrieved from the Hungarian National Health Insurance Fund database. In descriptive analysis, the public payer's spending was given as cost/capita. The impact of a decrease in prematurity prevalence was specified as the total budget impact. An exchange rate of 294 Hungarian forint/Euro was applied.

RESULTS

A total of 93,124 children (including 8.6% who were premature babies) were included in the analysis. A strong negative relationship was shown between gestational age and per capita cost. The 6-year cost of care for the cohort born at 26 weeks of gestation (28,470 Euro per capita) was 24 times higher than that for the cohort born at 40 weeks. First-year inpatient spending accounted for the largest proportion of total health care spending across all gestational ages. All investigated prematurity complications (retinopathy of prematurity, necrotizing enterocolitis, bronchopulmonary dysplasia, intraventricular cerebral bleeding and leukomalacia) resulted in additional significant incremental spending. If 70% of pregnancies ending with preterm birth could be prolonged by 1 week, the savings would be almost 7.0 million Euros in the first 6 years of life.

CONCLUSION

This comprehensive analysis of prematurity-related health care spending confirmed that premature infants have much higher costs for care than those born at term in Hungary. These quantitative outcomes can provide essential inputs for the cost-effectiveness analysis of medical technologies and public health interventions that can decrease the prevalence of premature birth.

TRIAL REGISTRATION

Not applicable.

Very-low-birth-weight infant short-term post-discharge outcomes: A retrospective study of specialized compared to standard care

OBJECTIVE

Ongoing health care challenges, low breast milk intake, and the need for rehospitalization are common during the first year of life after hospital discharge for very low birth weight (VLBW) infants. This retrospective cohort study examined breast milk intake, growth, emergency department (ED) visits, and non-surgical rehospitalizations for VLBW infants who received specialized post-discharge follow-up in western Canada, compared to VLBW infants who received standard follow-up in central Canada.

DESIGN

Data were collected from two neonatal follow-up programs for VLBW babies (n = 150 specialized-care; n = 205 standard-care). Logistic regression was used to examine odds of breast milk intake and generalized estimating equations were used for odds of growth, ED visits and non-surgical rehospitalization by site.

RESULTS

Specialized-care was associated with enhanced breast milk intake duration; the odds of receiving breastmilk at 4 months in the specialized-care cohort was 6 times that in the standard-care cohort. The specialized-care cohort had significantly more ED visits and rehospitalizations. However, for infants with oxygen use beyond 36 weeks compared to those with no oxygen use, the standard-care cohort had over 7 times the odds of rehospitalization where as the specialized-care cohort with no increased odds of rehospitalization.

CONCLUSION

Specialized neonatal nursing follow-up was associated with continued breastmilk intake beyond discharge. Infants in the specialized-care cohort used the ED and were hospitalized more often than the standard-care cohort with the exception of infants with long term oxygen needs.

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.

Health Economics of Selective Early Rescue Surfactant Administration and Standard Surfactant Administration for Newborns With Respiratory Distress Syndrome

OBJECTIVE

To quantify the effect of early rescue surfactant administration techniques for preterm infants with respiratory distress syndrome (RDS) from a health care delivery system perspective.

METHODS

A cost-consequence model was developed based on previously published literature to compare the health economic impact of implementing early surfactant administration strategies vs standard surfactant administration via endotracheal intubation and mechanical ventilation (MV).

RESULTS

Early rescue surfactant treatment strategies are associated with a decrease in the number of patients requiring MV, cumulative MV days, and rate of neonatal complications. Total annual surfactant costs are higher than standard surfactant administration, but this is offset by savings in total hospital and complication costs.

CONCLUSIONS

This cost-consequence analysis suggests selective early rescue surfactant administration strategies are associated with a lower health care burden in premature infants with RDS.

Racial identification represents significant risk factor for healthcare disparity among patients with severe bronchopulmonary dysplasia treated with tracheostomy

OBJECTIVES

To characterize the patient population with severe bronchopulmonary dysplasia (BPD) requiring tracheostomy in a large tertiary level 4 neonatal intensive care unit (NICU) and to identify potential targets for improvement in the delivery of high-quality healthcare.

METHODS

An IRB-exempt but IRB-registered retrospective review of medical records. Study inclusion criteria: patients treated for severe BPD with tracheostomy under 2 years of age in our tertiary referral center NICU. Control group criteria: 4-year aggregate NICU patient demographics. Basic demographics, maternal history, clinical data points, and outcomes variables were collected.

RESULTS

There was a statistically significant difference between the two groups in only one variable: racial identification (p-value = 0.036). All data points were then analyzed against racial identification, and statistically significant differences appeared in 4 categories: 1) illicit drug use, 2) birth head circumference and length, 3) days to readmission, and 4) child opportunity index scores. There was not a statistically significant difference in any other maternal characteristics or medical comorbidities, NICU length of stay, age at tracheostomy, or decannulation status.

CONCLUSION

The incidence of our tracheostomy in infants with severe BPD was significantly higher (p = 0.036) in the subjects whose families identified as racially African American or Black, a marked contrast to our general NICU population and our overall tracheostomy population. The timing of the first readmission to the hospital was shorter for Caucasian or White infants compared to African American or Black infants. COI demonstrated statistically significantly poorer resources for African American or Black infants compared to White infants with tracheostomy. All other perinatal and outcome measurements did not differ significantly between the two racial groups. This suggests that this racial disparity is present and needs further investigation to better assess its impact on risk and outcomes as we develop pathways for high-quality healthcare delivery.

Extracellular Signal-Regulated Kinase 1 Alone Is Dispensable for Hyperoxia-Mediated Alveolar and Pulmonary Vascular Simplification in Neonatal Mice

Bronchopulmonary dysplasia (BPD) is a morbid lung disease distinguished by lung alveolar and vascular simplification. Hyperoxia, an important BPD causative factor, increases extracellular signal-regulated kinases (ERK)-1/2 expression, whereas decreased lung endothelial cell ERK2 expression reduces angiogenesis and potentiates hyperoxia-mediated BPD in mice. However, ERK1′s role in experimental BPD is unclear. Thus, we hypothesized that hyperoxia-induced experimental BPD would be more severe in global ERK1-knockout (ERK1^-/-) mice than their wild-type (ERK1^+/+ mice) littermates. We determined the extent of lung development, ERK1/2 expression, inflammation, and oxidative stress in ERK1^-/- and ERK1^+/+ mice exposed to normoxia (FiO₂ 21%) or hyperoxia (FiO₂ 70%). We also quantified the extent of angiogenesis and hydrogen peroxide (H₂O₂) production in hyperoxia-exposed neonatal human pulmonary microvascular endothelial cells (HPMECs) with normal and decreased ERK1 signaling. Compared with ERK1^+/+ mice, ERK1^-/- mice displayed increased pulmonary ERK2 activation upon hyperoxia exposure. However, the extent of hyperoxia-induced inflammation, oxidative stress, and interrupted lung development was similar in ERK1^-/- and ERK1^+/+ mice. ERK1 knockdown in HPMECs increased ERK2 activation at baseline, but did not affect in vitro angiogenesis and hyperoxia-induced H₂O₂ production. Thus, we conclude ERK1 is dispensable for hyperoxia-induced experimental BPD due to compensatory ERK2 activation.

Severe bronchopulmonary dysplasia in extremely premature infants: a scoping review protocol for identifying risk factors

INTRODUCTION

The remarkable improvement in the long-term prognosis of extremely premature infants has led to an increase in the number of cases of bronchopulmonary dysplasia (BPD). BPD affects pulmonary function and developmental outcomes, resulting in high chronic health burdens for infants and their families over the years. Therefore, identifying its risk factors in the early period of life and exploring better prophylactics and treatment strategies are important.The objectives of our scoping review are to screen available evidence, identify perinatal risk factors involved in the development and severity of BPD and devise a novel disease classification system that can predict long-term prognosis.

METHODS AND ANALYSIS

Eligibility criteria are as follows: articles published from 2002 to 2021; studies conducted in developed countries; articles written in English (PubMed) or Japanese (Ichushi); randomised controlled trials, prospective/retrospective cohort studies or case-control studies; extremely premature infants born before 28 weeks of gestational age; and articles in which endpoint was severe BPD as classified by the National Institute of Child Health and Human Development.We will screen the titles and abstracts of studies identified by independent reviewers using the population-concept-context framework. After a full-text review and data charting, we will provide the perinatal risk factors for severe BPD along with the risk ratio or odds ratio, 95% confidence interval and p values.

ETHICS AND DISSEMINATION

Institutional review board approval is not required due to the nature of the study. The results of this review will be disseminated through peer-reviewed publications and presentations at relevant conferences.Protocol V.1, 22 September 2021 TRIAL REGISTRATION NUMBER: UMIN000045529.

Novel Ventilation Strategies to Reduce Adverse Pulmonary Outcomes

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

The Aryl Hydrocarbon Receptor (AHR): A Novel Therapeutic Target for Pulmonary Diseases?

The aryl hydrocarbon receptor (AHR) is a cytoplasmic transcription factor that is well-known for regulating xenobiotic metabolism. Studies in knockout and transgenic mice indicate that the AHR plays a vital role in the development of liver and regulation of reproductive, cardiovascular, hematopoietic, and immune homeostasis. In this focused review on lung diseases associated with acute injury and alveolar development, we reviewed and summarized the current literature on the mechanistic role(s) and therapeutic potential of the AHR in acute lung injury, chronic obstructive pulmonary disease, and bronchopulmonary dysplasia (BPD). Pre-clinical studies indicate that endogenous AHR activation is necessary to protect neonatal and adult lungs against hyperoxia- and cigarette smoke-induced injury. Our goal is to provide insight into the high translational potential of the AHR in the meaningful management of infants and adults with these lung disorders that lack curative therapies.

Comparisons of two definitions of bronchopulmonary dysplasia for the premature infants

OBJECTIVE

Bronchopulmonary dysplasia (BPD) is a very common respiratory disease in premature infants, but there is still a different understanding of the definition of BPD. Therefore, this study is intended to compare are main clinical results and health economic expenditures under different BPD definitions.

METHODS

This study included premature infants who came into the neonatal intensive care unit (NICU) from January 2018 to January 2020, who were not more than 32 weeks of premenstrual age. The main clinical consequences and health economic expenditures were analyzed by the National Institute of Health and Human Development definition (Workshop) and Jensen definition.

RESULTS

Total 303 survivors were evaluated at 36 weeks. BPD was performed in 47.5% and 37.6% of infants, respectively, with Workshop's and Jensen's definitions. The percentage of unclassified BPD infants was 0.9% in Workshop's and 3.3% in Jensen's definitions. Further discussing the health economic burden and found that Jensen's definitions had a significantly correlated with NICU charges than the Workshop's definitions.

CONCLUSION

Comparing the Workshop definition of BPD, the Jensens definition was better correlated to health expenditure.

Impact of early respiratory care for extremely preterm infants

Despite advances in neonatal intensive care, more than half of surviving infants born extremely preterm (EP; < 28 weeks' gestation) develop bronchopulmonary dysplasia (BPD). Prevention of BPD is critical because of its associated mortality and morbidity, including adverse neurodevelopmental outcomes and respiratory health in later childhood and beyond. The respiratory care of EP infants begins before birth, then continues in the delivery room and throughout the primary hospitalization. This chapter will review the evidence for interventions after birth that might improve outcomes for infants born EP, including the timing of umbilical cord clamping, strategies to avoid or minimize exposure to mechanical ventilation, modes of mechanical ventilation and non-invasive respiratory support, oxygen saturation targets, postnatal corticosteroids and other adjunct therapies.

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

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

Systematic review of the healthcare cost of bronchopulmonary dysplasia

OBJECTIVES

To determine the costs directly or indirectly related to bronchopulmonary dysplasia (BPD) in preterm infants. The secondary objective was to stratify the costs based on gestational age and/or birth weight.

DESIGN

Systematic literature review.

SETTING

PubMed and Scopus were searched on 3 February 2020. Studies were selected based on eligibility criteria by two independent reviewers. Included studies were further searched to identify eligible references and citations.Two independent reviewers extracted data with a prespecified data extraction sheet, including items from a published checklist for quality assessment. The costs in the included studies are reported descriptively.

PRIMARY OUTCOME MEASURE

Costs of BPD.

RESULTS

The 13 included studies reported the total costs or marginal costs of BPD. Most studies reported costs during birth hospitalisation (cost range: Int$21 392-Int$1 094 509 per child, equivalent to €19 103-€977 397, in 2019) and/or during the first year of life. One study reported costs during the first 2 years; two other studies reported costs later, during the preschool period and one study included a long-term follow-up. The highest mean costs were associated with infants born at extremely low gestational ages. The quality assessment indicated a low risk of bias in the reported findings of included studies.

CONCLUSIONS

This study was the first systematic review of costs associated with BPD. We confirmed previous reports of high costs and described the long-term follow-up necessary for preterm infants with BPD, particularly infants of very low gestational age. Moreover, we identified a need for studies that estimate costs outside hospitals and after the first year of life.

PROSPERO REGISTRATION NUMBER

CRD42020173234.

Duration of mechanical ventilation and prediction of bronchopulmonary dysplasia and home oxygen in extremely preterm infants

AIM

To determine whether the duration of invasive ventilation predicted the development of bronchopulmonary dysplasia (BPD) and need for discharge home on supplementary oxygen in extremely preterm infants.

METHODS

Retrospective whole-population study of all infants <28 weeks of gestation admitted to a neonatal unit in England between 2014 and 2018. BPD development was defined as any respiratory support at 36 weeks postmenstrual age. The performance of the duration of mechanical ventilation to predict BPD or discharge home on oxygen was assessed by receiver operator characteristic curve analysis.

RESULTS

The 11,806 infants had a median (IQR) gestational age of 26.0(24.9-27.1) weeks and birthweight of 0.81(0.67-0.96) kg. At discharge from neonatal care, 9,415 infants (79.7%) were alive. The incidence of BPD was 57.5% and of home oxygen 29.4%. Mechanical ventilation duration had areas under the curve of 0.793 and 0.703 in predicting BPD and home oxygen, respectively. Mechanical ventilation for >8 days predicted BPD development with 71% sensitivity and 71% specificity and mechanical ventilation for >10 days predicted discharge on home oxygen with 66% sensitivity and 65% specificity.

CONCLUSION

In extremely preterm infants, the duration of invasive support predicted BPD and need for home oxygen with moderate sensitivity and specificity.

Anemia, nutrition, and ambulatory oxygen weaning in a cohort of oxygen-dependent premature infants

BACKGROUND

In Bogotá, Colombia, oxygen-dependent (OD) preterm infants are home discharged in Kangaroo Position, to a Kangaroo Mother Care Program (KMCP) with ambulatory oxygen, strict follow-up, and oxygen weaning protocols.

OBJECTIVES

(1) To describe growth, morbimortality, and oxygen monitoring up to 6 months in OD preterm infants. (2) To explore associations between oxygen weaning, perinatal history, Hb levels, transfusions, feeding patterns, and growth.

METHODS

A prospective cohort study. Descriptive and multivariate analysis.

RESULTS

Recruited patients were 407 with 33 weeks median gestational age (GA). Mothers presented infections >28%, pre-eclampsia in 22%, and 80% received antenatal corticosteroids. Upon KMCP admission, median GA, chronological age, and hospital stay were 36 weeks, 21 and 17 days, respectively; 56.8% of patients had neonatal sepsis and 67.8% were admitted to the neonatal intensive care unit. At oxygen weaning, patients had a median of 54 days with oxygen, median weight 3240 g and GA 41 weeks. Median follow-up oxygen saturation was 94% with 1/64-1/2 L/min of oxygen. One-year mortality was 0.2% and attrition 20%. At 6 months, all patients had appropriate growth and 67% were breastfeeding. Multiple regression analysis showed that higher GA, Hb levels, weight gain, and exclusive breastfeeding decreased oxygen requirement while invasive ventilation and transfusions had the opposite effect (R²  = .49).

CONCLUSIONS

In OD preterm infants, there is a close relationship between days of oxygen requirement and GA, mechanical ventilation, Hb levels at discharge, transfusions, exclusive breastfeeding, and weight gain. Strict monitoring with established protocols in an ambulatory KMCP allows adequate growth and safe oxygen weaning.

Increasing Volume-Targeted Ventilation Use in the NICU

BACKGROUND

In preterm infants who require mechanical ventilation (MV), volume-targeted ventilation (VTV) modes are associated with lower rates of bronchopulmonary dysplasia compared with pressure-limited ventilation. Bronchopulmonary dysplasia rates in our NICU were higher than desired, prompting quality improvement initiatives to improve MV by increasing the use of VTV.

METHODS

We implemented and tested interventions over a 3-year period. Primary outcomes were the percentage of conventional MV hours when any-VTV mode was used and the percentage of conventional MV hours when an exclusively VTV mode was used. Exclusively VTV modes were modes in which all breaths were volume targeted. We evaluated outcomes during 3 project periods: baseline (May 2016-December 2016); epoch 1 (December 2016-October 2018), increasing the use of any-VTV mode; and epoch 2 (October 2018-November 2019), increasing the use of exclusively VTV modes.

RESULTS

Use of any-VTV mode increased from 18 694 of 22 387 (83%) MV hours during baseline to 72 846 of 77 264 (94%) and 58 174 of 60 605 (96%) MV hours during epochs 1 and 2, respectively (P < .001). Use of exclusively VTV increased from 5967 of 22 387 (27%) during baseline to 47 364 of 77 264 (61%) and 46 091 of 60 605 (76%) of all conventional MV hours during epochs 1 and 2, respectively (P < .001). In statistical process control analyses, multiple interventions were associated with improvements in primary outcomes. Measured clinical outcomes were unchanged.

CONCLUSIONS

Quality improvement interventions were associated with improved use of VTV but no change in measured clinical outcomes.

A Quality Improvement Initiative to Reduce Bronchopulmonary Dysplasia in a Level 4 NICU-Golden Hour Management of Respiratory Distress Syndrome in Preterm Newborns

BACKGROUND

Prevention of chronic lung disease (CLD) requires a multidisciplinary approach spanning from the delivery room to Neonatal Intensive Care Unit (NICU) discharge. In 2018, a quality improvement (QI) initiative commenced in a level 4 NICU with the goal of decreasing chronic lung disease rates below the Vermont Oxford Network (VON) average of 24%.

METHODS

Improvement strategies focused on addressing the primary drivers of ventilation strategies, surfactant administration, non-invasive ventilation, medication use, and nutrition/fluid management. The primary outcome was VON CLD, defined as need for mechanical ventilation and/or supplemental oxygen use at 36 weeks postmenstrual age. Statistical process control charts were used to display and analyze data over time.

RESULTS

The overall CLD rate decreased from 33.5 to 16.5% following several interventions, a 51% reduction that has been sustained for >18 months. Changes most attributable to this include implementation of the "golden hour" gestational age (GA) based delivery room protocol that encourages early surfactant administration and timely extubation. Fewer infants were intubated across all GA groups with the largest improvement among infants 26-27 weeks GA.

CONCLUSIONS

Our efforts significantly decreased CLD through GA-based respiratory guidelines and a comprehensive, rigorous QI approach that can be applicable to other teams focused on improvement.

A comparison of LISA versus InSurE: A single center experience

BACKGROUND

Less invasive surfactant replacement therapy (SRT) methods have been linked to better respiratory outcomes. The primary aim of this study was to determine if Less Invasive Surfactant Administration (LISA) altered the rate of bronchopulmonary dysplasia (BPD) in preterm infants. Secondary objectives were to determine if LISA compared to Intubation Surfactant Extubation (InSurE) resulted in different respiratory outcomes and hospital course.

METHODS

In this retrospective chart review, outcomes were compared in two preterm infant groups (25-32 weeks gestation). Infants in Group 1 received surfactant replacement therapy (SRT) via InSurE method, while infants in Group 2 received SRT via LISA method.

RESULTS

Regardless of SRT method utilized, there were no significant differences in rates of BPD between the two groups in infants born at 25-32 weeks gestation (30.6% vs 33.3%; P = 0.47).

CONCLUSIONS

Despite using LISA method rather than InSurE for SRT, premature infants continue to be at high risk for BPD. LISA shows promise as a safe, noninvasive SRT alternative to invasive methods like InSurE.

Newer bronchopulmonary dysplasia definitions and prediction of health economics impacts in very preterm infants

OBJECTIVE

To compare the abilities of bronchopulmonary dysplasia (BPD) definitions to predict hospital charges as a surrogate of disease complexity.

METHODS

Retrospective study of infants admitted to the neonatal intensive care unit (NICU) less than 32 weeks gestational age. Subjects were classified according to the Canadian Neonatal Network (CNN), the National Institute of Child Health and Human Development (NICHD) (2018), and Jensen BPD definitions as none, mild (1), moderate (2), or severe (3) BPD. Spearman's correlation was performed to evaluate the association of BPD definitions with health economics outcomes.

RESULTS

One hundred and sixty-eight infants were included with mean birth weight of 1197 g and mean gestational age of 28.4 weeks. More infants were classified as no BPD according to CNN definition (79%) in comparison to NICHD 2018 (64.3%) and Jensen (59.5%) definitions. There were fewer infants as the grade of severity increased for all definitions, this was most linear for Jensen definition with Grade 1 present in 25%, Grade 2 in 12.5%, and Grade 3 in 3%. A stronger correlation with NICU length of stay, NICU hospital charges, NICU charges per day, and first year of life hospital charges was detected for Jensen definition (correlation coefficient of 0.58, 0.66, 0.64, 0.67, respectively) in comparison to CNN and NICHD 2018 definitions (p < .0001).

CONCLUSION

Jensen BPD definition had the strongest correlation with first year health economics outcomes in our study. Validating recent BPD definitions using population-based data is imperative to improve family counseling and enhance the designs of quality improvement initiatives and therapeutic research studies targeting patient-centric outcomes.

New BPD-prevalence and risk factors for bronchopulmonary dysplasia/mortality in extremely low gestational age infants ≤28 weeks

OBJECTIVE

To evaluate prevalence and risk factors of moderate-severe Bronchopulmonary dysplasia (BPD)/Death in extremely low gestation age neonates (ELGANs).

STUDY DESIGN

Study of 266 ELGANs born at gestational age (GA) ≤ 28 weeks (w). Primary Outcome measure-composite outcome of moderate-severe BPD/Death using the National Institute of Child Health and Human Development NICHD's (2001) BPD definition.

RESULT

Cohort's mean GA and birth-weight (BW) were 25.3 ± 1.4w and 724 ± 14 g respectively with an overall mortality of 19% and moderate-severe BPD of 67%. Prevalence of moderate-severe BPD/death decreased significantly with increasing GA (86-93%) at 23-24 w; to <60% at 27-28w (OR 0.63; 95% CI; 0.52-0.77). On univariate analysis, other risk factors included BW(OR 1.005; 95% CI; 1.003-1.007), Sepsis (OR 2.9; 95% CI, 1.3-6.4), PDA needing treatment (OR 2.2; 95% CI, 1.3-3.9); air leaks (OR 2.7; 95% CI; 1.02-7.3) FiO₂ requirement >25%(OR 1.06; 95% CI; 1.01-1.11); and mechanical ventilation(MV) on Day7 (OR5.5; 95% CI; 2.8-10.8). Only need for Day7 MV was independently predictive of composite outcome (OR1.97; 95% CI; 1.3-3.1).

CONCLUSION

Risk factor identification will enable initiatives to implement lung protective strategies and develop prospective models for BPD prediction and prognostication.

Interactive and independent effects of early lipopolysaccharide and hyperoxia exposure on developing murine lungs

Bronchopulmonary dysplasia (BPD)-associated pulmonary hypertension (PH) is a chronic infantile lung disease that lacks curative therapies. Infants with BPD-associated PH are often exposed to hyperoxia and additional insults such as sepsis that contribute to disease pathogenesis. Animal models that simulate these scenarios are necessary to develop effective therapies; therefore, we investigated whether lipopolysaccharide (LPS) and hyperoxia exposure during saccular lung development cooperatively induce experimental BPD-PH in mice. C57BL/6J mice were exposed to normoxia or 70% O₂ (hyperoxia) during postnatal days (PNDs) 1-5 and intraperitoneally injected with varying LPS doses or a vehicle on PNDs 3-5. On PND 14, we performed morphometry, echocardiography, and gene and protein expression studies to determine the effects of hyperoxia and LPS on lung development, vascular remodeling and function, inflammation, oxidative stress, cell proliferation, and apoptosis. LPS and hyperoxia independently and cooperatively affected lung development, inflammation, and apoptosis. Growth rate and antioxidant enzyme expression were predominantly affected by LPS and hyperoxia, respectively, while cell proliferation and vascular remodeling and function were mainly affected by combined exposure to LPS and hyperoxia. Mice treated with lower LPS doses developed adaptive responses and hyperoxia exposure did not worsen their BPD phenotype, whereas those mice treated with higher LPS doses displayed the most severe BPD phenotype when exposed to hyperoxia and were the only group that developed PH. Collectively, our data suggest that an additional insult such as LPS may be necessary for models utilizing short-term exposure to moderate hyperoxia to recapitulate human BPD-PH.

Tie-2 Cre-Mediated Deficiency of Extracellular Signal-Regulated Kinase 2 Potentiates Experimental Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension in Neonatal Mice

Bronchopulmonary dysplasia (BPD)-associated pulmonary hypertension (PH) is a significant lung morbidity of infants, and disrupted lung angiogenesis is a hallmark of this disease. We observed that extracellular signal-regulated kinases (ERK) 1/2 support angiogenesis in vitro, and hyperoxia activates ERK1/2 in fetal human pulmonary microvascular endothelial cells (HPMECs) and in neonatal murine lungs; however, their role in experimental BPD and PH is unknown. Therefore, we hypothesized that Tie2 Cre-mediated deficiency of ERK2 in the endothelial cells of neonatal murine lungs would potentiate hyperoxia-induced BPD and PH. We initially determined the role of ERK2 in in vitro angiogenesis using fetal HPMECs. To disrupt endothelial ERK2 signaling in the lungs, we decreased ERK2 expression by breeding ERK2^flox/flox mice with Tie-Cre mice. One-day-old endothelial ERK2-sufficient (eERK2^+/+) or –deficient (eERK2^+/−) mice were exposed to normoxia or hyperoxia (FiO₂ 70%) for 14 d. We then performed lung morphometry, gene and protein expression studies, and echocardiography to determine the extent of inflammation, oxidative stress, and development of lungs and PH. The knockdown of ERK2 in HPMECs decreased in vitro angiogenesis. Hyperoxia increased lung inflammation and oxidative stress, decreased lung angiogenesis and alveolarization, and induced PH in neonatal mice; however, these effects were augmented in the presence of Tie2-Cre mediated endothelial ERK2 deficiency. Therefore, we conclude that endothelial ERK2 signaling is necessary to mitigate hyperoxia-induced experimental BPD and PH in neonatal mice. Our results indicate that endothelial ERK2 is a potential therapeutic target for the management of BPD and PH in infants.

Novel Strategies to Reduce Pulmonary Hypertension in Infants With Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a developmental lung disorder of preterm infants primarily caused by the failure of host defense mechanisms to prevent tissue injury and facilitate repair. This disorder is the most common complication of premature birth, and its incidence remains unchanged over the past few decades. Additionally, BPD increases long-term cardiopulmonary and neurodevelopmental morbidities of preterm infants. Pulmonary hypertension (PH) is a common morbidity of BPD. Importantly, the presence of PH increases both the short- and long-term morbidities and mortality in BPD infants. Further, there are no curative therapies for this complex disease. Besides providing an overview of the pathogenesis and diagnosis of PH associated with BPD, we have attempted to comprehensively review and summarize the current literature on the interventions to prevent and/or mitigate BPD and PH in preclinical studies. Our goal was to provide insight into the therapies that have a high translational potential to meaningfully manage BPD patients with PH.