Bronchopulmonary Dysplasia: An Update of Current Pharmacologic Therapies and New Approaches

Risk Factors for Foster Care Placement in Patients with Bronchopulmonary Dysplasia

OBJECTIVE

Bronchopulmonary dysplasia (BPD) is a major cause of morbidity in neonates and can be associated with long hospitalization and high health care utilization. This extremely stressful situation can be difficult for many families and caregivers. The high-risk situation combined with increased medical complexity can result in involvement of Department of Child Services (DCS) and even foster care placement. This study seeks to define risk factors for DCS involvement and foster care placement in children with BPD.

STUDY DESIGN

A retrospective study of children born at less than 32 weeks of gestation born between 2010 and 2016, on oxygen at 28 days of life and discharged home from a tertiary care center.

RESULTS

A total of 246 patients were identified. DCS was involved in 49 patients with 13 requiring foster care placement. The most common correlated risk factors that were identified for DCS involvement were maternal THC (tetrahydrocannabinol) positivity, hospital policy violations, maternal mental health diagnosis, and home insecurity. Home insecurity (p < 0.005) and amphetamine use (p < 0.005) were associated with foster care placement.

CONCLUSION

There are numerous risk factors for both DCS and foster care placement. The identification of these risk factors is important to help establish services to help families and identify potential biases to avoid.

KEY POINTS

· There were both substance-related and non-substance-related risk factors for DCS involvement.. · Home insecurity and maternal amphetamine use were risk factors associated with foster care placement.. · This study fills the knowledge gap of risk factors for DCS and foster care placement in BPD..

Diuretics use in the management of bronchopulmonary dysplasia in preterm infants: A systematic review

AIM

Bronchopulmonary dysplasia (BPD), a respiratory complication associated with neonatal prematurity, presents opportunities for pharmacological intervention due to its contributing risk factors. Despite diuretics' controversial usage in BPD treatment and varying institutional practices, this review aims to consolidate evidence from clinical trials regarding diuretic use in BPD.

METHODS

We conducted a systematic review following PRISMA guidelines, searching EMBASE, Medline, Web of Science and CINAHL databases (PROSPERO 2022: CRD42022328292). Covidence facilitated screening and data extraction, followed by analysis and formatting in Microsoft Excel.

RESULTS

Among 430 screened records, 13 were included for analysis. Three studies assessed spironolactone and chlorothiazide combinations, two studied spironolactone and hydrochlorothiazide, while eight examined furosemide. All studies evaluated drug effects on dynamic pulmonary compliance and pulmonary resistance, serving as comparative measures in our review.

CONCLUSION

Diuretics' effectiveness in treating bronchopulmonary dysplasia remains uncertain. The limited number of identified randomised controlled trials (RCTs) hampers high-level evidence-based conclusions when applying the Population, Intervention, Comparison, Outcome (PICO) approach. Conducting large prospective studies of good quality could provide more definitive insights, but the rarity of outcomes and eligible patients poses challenges. Further research, primarily focusing on RCTs assessing diuretics' safety and efficacy in this population, is warranted.

Predictive and Diagnostic Values of Systemic Inflammatory Indices in Bronchopulmonary Dysplasia

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the most common respiratory complication in preterm infants, and there is a lag in the diagnosis of BPD. Inflammation is a vital pathogenic factor for BPD; we aim to evaluate the predictive and diagnostic values of systemic inflammatory indices in BPD.

METHODS

Between 1 January 2019 and 31 May 2023, the clinical data of 122 premature infants with a gestational age of <32 weeks in the Department of Neonatology, the Affiliated Huai'an No. 1 People's Hospital of Nanjing Medical University, were retrospectively collected and classified into non-BPD (n = 72) and BPD (n = 50) groups based on the National Institute of Child Health and Human Development 2018 criteria. To compare the general characteristics of each group, we identified the independent risk variables for BPD using multivariate logistic regression analysis, compared the systemic inflammatory indices at birth, 72 h, 1 week, 2 weeks, and 36 weeks postmenstrual age (PMA), and constructed the receiver operating characteristic curves of neutrophil-to-lymphocyte ratio (NLR) diagnosis of BPD at different time points.

RESULTS

① The independent risk factors for BPD in preterm infants were birth weight, small for gestational age, and days of oxygen therapy (all p < 0.05). ② At 72 h and 1 week after birth, the serum NLR of the BPD group was higher than for the non-BPD group (p < 0.05). Furthermore, the neutrophil count (N), NLR, monocyte-to-lymphocyte ratio (MLR), systemic immune-inflammation index, systemic inflammation response index (SIRI), and pan-immune-inflammation value of infants with BPD were higher than the non-BPD group at 3 weeks after birth (p < 0.05). Moreover, at 36 weeks of PMA, the serum N, NLR, MLR, and SIRI of BPD infants were higher than those of non-BPD infants (p < 0.05). ③ The NLR of infants with and without BPD gradually increased after birth, reaching a peak at 72 h and 1 week, respectively. At 3 weeks postnatal, the NLR had the highest predictive power for BPD, with an area under the curve (AUC) of 0.717 (p < 0.001); the sensitivity was 56% and specificity was 86.1%. In addition, the NLR at 36 weeks of PMA exhibited some diagnostic value for BPD. The AUC was 0.693 (p < 0.001), the sensitivity was 54%, and specificity was 83.3%.

CONCLUSIONS

At 3 weeks after birth and 36 weeks of PMA, some systemic inflammation indices (like N, NLR, SIRI) of preterm infants with BPD have specific predictive and diagnostic values; these indices may help the management of high-risk preterm infants with BPD.

Furin Regulates the Alveolarization of Neonatal Lungs in a Mouse Model of Hyperoxic Lung Injury

Despite advances in treatment options, such as corticosteroid administration and less invasive respiratory support, bronchopulmonary dysplasia (BPD) remains an important prognostic factor in preterm infants. We previously reported that furin regulates changes in lung smooth muscle cell phenotypes, suggesting that it plays a critical role in BPD pathogenesis. Therefore, in this study, we aimed to evaluate whether it regulates the alveolarization of immature lungs through activating alveolarization-driving proteins. We first examined furin expression levels, and its functions, using an established hyperoxia-induced BPD mouse model. Thereafter, we treated mice pups, as well as primary myofibroblast cell cultures, with furin inhibitors. Finally, we administered the hyperoxia-exposed mice pups with recombinant furin. Immunofluorescence revealed the co-expression of furin with alpha-smooth muscle actin. Hyperoxia exposure for 10 d decreased alveolar formation, as well as the expression of furin and its target, IGF-1R. Hexa-D-arginine administration also significantly inhibited alveolar formation. Another furin inhibitor, decanoyl-RVKR-chloromethylketone, accumulated pro-IGF-1R, and decreased IGF-1R phosphorylation in myofibroblast primary cultures. Finally, recombinant furin treatment significantly improved alveolarization in hyperoxia-exposed mice pups. Furin regulates alveolarization in immature lungs. Therefore, this study provides novel insights regarding the involvement of furin in BPD pathogenesis, and highlights a potential treatment target for ameliorating the impact of BPD.

L-citrulline attenuates lipopolysaccharide-induced inflammatory lung injury in neonatal rats

BACKGROUND

Prenatal or postnatal lung inflammation and oxidative stress disrupt alveolo-vascular development leading to bronchopulmonary dysplasia (BPD) with and without pulmonary hypertension. L-citrulline (L-CIT), a nonessential amino acid, alleviates inflammatory and hyperoxic lung injury in preclinical models of BPD. L-CIT modulates signaling pathways mediating inflammation, oxidative stress, and mitochondrial biogenesis-processes operative in the development of BPD. We hypothesize that L-CIT will attenuate lipopolysaccharide (LPS)-induced inflammation and oxidative stress in our rat model of neonatal lung injury.

METHODS

Newborn rats during the saccular stage of lung development were used to investigate the effect of L-CIT on LPS-induced lung histopathology and pathways involved in inflammatory, antioxidative processes, and mitochondrial biogenesis in lungs in vivo, and in primary culture of pulmonary artery smooth muscle cells, in vitro.

RESULTS

L-CIT protected the newborn rat lung from LPS-induced: lung histopathology, ROS production, NFκB nuclear translocation, and upregulation of gene and protein expression of inflammatory cytokines (IL-1β, IL-8, MCP-1α, and TNF-α). L-CIT maintained mitochondrial morphology, increased protein levels of PGC-1α, NRF1, and TFAM (transcription factors involved in mitochondrial biogenesis), and induced SIRT1, SIRT3, and superoxide dismutases protein expression.

CONCLUSION

L-CIT may be efficacious in decreasing early lung inflammation and oxidative stress mitigating progression to BPD.

IMPACT

The nonessential amino acid L-citrulline (L-CIT) mitigated lipopolysaccharide (LPS)-induced lung injury in the early stage of lung development in the newborn rat. This is the first study describing the effect of L-CIT on the signaling pathways operative in bronchopulmonary dysplasia (BPD) in a preclinical inflammatory model of newborn lung injury. If our findings translate to premature infants, L-CIT could decrease inflammation, oxidative stress and preserve mitochondrial health in the lung of premature infants at risk for BPD.

Respiratory management of established severe bronchopulmonary dysplasia

Respiratory management of infants with established severe BPD is difficult and there is little evidence upon which to base decisions. Nonetheless, the physiology of severe BPD is well described with a predominantly obstructive pattern. This pulmonary dysfunction results in prolonged exhalatory time constants and thus ventilator management must be focused on maintaining adequate oxygenation and ventilation through achieving full exhalation. This approach is often difficult to maintain in acute care settings and a culture of chronic care focused on slow change and steady progress is imperative. Once respiratory stability is achieved, the focus should shift to growth and development and avoidance of care practices and medications that impair neurodevelopment.

Nutrition-based implications and therapeutics in the development and recovery of bronchopulmonary dysplasia

Premature births account for over 10% of live births worldwide. Bronchopulmonary dysplasia (BPD) represents a severe sequela in neonates born very prematurely and remains the most common chronic neonatal lung disease, often leading to serious adverse consequences in adulthood. Nutrition plays a crucial role in lung development and repair. Ongoing research has primarily focused on the pathogenesis and prevention of BPD in preterm birth. However, infants with established BPD need specialist medical care that persists throughout their hospitalization and continues after discharge. This manuscript aims to highlight the impact of growth and nutrition on BPD and highlight research gaps to provide direction for future studies. Protective practices include ensuring adequate early energy delivery through parenteral nutrition and enteral feedings while carefully monitoring total fluid intake and the use of breast milk over formula. These nutritional strategies remain the same for infants with established BPD with the addition of limiting the use of diuretics and steroids; but if employed, monitoring carefully without compromising total energy delivery. Functional nutrient supplements with a potential protective role against BPD are revisited, despite the limited evidence of their efficacy, including vitamins, trace elements, zinc, lipids, and sphingolipids. Planning post-intensive care and outpatient longitudinal nutrition support is critical in caring for an infant with established BPD.

A Paternal Fish Oil Diet Preconception Reduces Lung Inflammation in a Toxicant-Driven Murine Model of New Bronchopulmonary Dysplasia

New bronchopulmonary dysplasia (BPD) is a neonatal disease that is theorized to begin in utero and manifests as reduced alveolarization due to inflammation of the lung. Risk factors for new BPD in human infants include intrauterine growth restriction (IUGR), premature birth (PTB) and formula feeding. Using a mouse model, our group recently reported that a paternal history of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure increased his offspring's risk of IUGR, PTB, and new BPD. Additionally, formula supplementation of these neonates worsened the severity of pulmonary disease. In a separate study, we reported that a paternal preconception fish oil diet prevented TCDD-driven IUGR and PTB. Not surprisingly, eliminating these two major risk factors for new BPD also significantly reduced development of neonatal lung disease. However, this prior study did not examine the potential mechanism for fish oil's protective effect. Herein, we sought to determine whether a paternal preconception fish oil diet attenuated toxicant-associated lung inflammation, which is an important contributor to the pathogenesis of new BPD. Compared to offspring of standard diet TCDD-exposed males, offspring of TCDD-exposed males provided a fish oil diet prior to conception exhibited a significant reduction in pulmonary expression of multiple pro-inflammatory mediators (Tlr4, Cxcr2, Il-1 alpha). Additionally, neonatal lungs of pups born to fish oil treated fathers exhibited minimal hemorrhaging or edema. Currently, prevention of BPD is largely focused on maternal strategies to improve health (e.g., smoking cessation) or reduce risk of PTB (e.g., progesterone supplementation). Our studies in mice support a role for also targeting paternal factors to improve pregnancy outcomes and child health.

Vascular Endothelial Growth Factor as Molecular Target for Bronchopulmonary Dysplasia Prevention in Very Low Birth Weight Infants

Bronchopulmonary dysplasia (BPD) still represents an important burden of neonatal care. The definition of the disease is currently undergoing several revisions, and, to date, BPD is actually defined by its treatment rather than diagnostic or clinic criteria. BPD is associated with many prenatal and postnatal risk factors, such as maternal smoking, chorioamnionitis, intrauterine growth restriction (IUGR), patent ductus arteriosus (PDA), parenteral nutrition, sepsis, and mechanical ventilation. Various experimental models have shown how these factors cause distorted alveolar and vascular growth, as well as alterations in the composition and differentiation of the mesenchymal cells of a newborn's lungs, demonstrating a multifactorial pathogenesis of the disease. In addition, inflammation and oxidative stress are the common denominators of the mechanisms that contribute to BPD development. Vascular endothelial growth factor-A (VEGFA) constitutes the most prominent and best studied candidate for vascular development. Animal models have confirmed the important regulatory roles of epithelial-expressed VEGF in lung development and function. This educational review aims to discuss the inflammatory pathways in BPD onset for preterm newborns, focusing on the role of VEGFA and providing a summary of current and emerging evidence.

Diagnostic efficacy of targeted high-throughput sequencing for lower respiratory infection in preterm infants

OBJECTIVE

To examine the pathogen diagnostic performance of targeted high-throughput next-gen sequencing (tNGS) in respiratory infectious diseases in preterm infants using dynamic follow-up.

METHODS

Clinical samples of respiratory secretions were consecutively collected from 20 preterm infants weekly for 5 weeks, during which 10 developed bronchopulmonary dysplasia. Pathogen identification from these collected specimens was performed by both conventional cultivation and tNGS.

RESULTS

We found that targeted next-generation sequencing shared a 90.9% full or partial consistency for lower respiratory pathogen detection with the traditional culture-based approach, and increased the detection rate by 105.9%. Moreover, most of the pathogens identified by tNGS were diminished in patients after treatment.

CONCLUSION

This study reveals the high sensitivity and performance of targeted high-throughput sequencing for respiratory infectious disease diagnosis and pathogen identification. The trial registry number is NCT03850457, and the trial URL is https://clinicaltrials.gov/ct2/show/NCT03850457.

Landscape analysis for a neonatal disease progression model of bronchopulmonary dysplasia: Leveraging clinical trial experience and real-world data

The 21^st Century Cures Act requires FDA to expand its use of real-world evidence (RWE) to support approval of previously approved drugs for new disease indications and post-marketing study requirements. To address this need in neonates, the FDA and the Critical Path Institute (C-Path) established the International Neonatal Consortium (INC) to advance regulatory science and expedite neonatal drug development. FDA recently provided funding for INC to generate RWE to support regulatory decision making in neonatal drug development. One study is focused on developing a validated definition of bronchopulmonary dysplasia (BPD) in neonates. BPD is difficult to diagnose with diverse disease trajectories and few viable treatment options. Despite intense research efforts, limited understanding of the underlying disease pathobiology and disease projection continues in the context of a computable phenotype. It will be important to determine if: 1) a large, multisource aggregation of real-world data (RWD) will allow identification of validated risk factors and surrogate endpoints for BPD, and 2) the inclusion of these simulations will identify risk factors and surrogate endpoints for studies to prevent or treat BPD and its related long-term complications. The overall goal is to develop qualified, fit-for-purpose disease progression models which facilitate credible trial simulations while quantitatively capturing mechanistic relationships relevant for disease progression and the development of future treatments. The extent to which neonatal RWD can inform these models is unknown and its appropriateness cannot be guaranteed. A component of this approach is the critical evaluation of the various RWD sources for context-of use (COU)-driven models. The present manuscript defines a landscape of the data including targeted literature searches and solicitation of neonatal RWD sources from international stakeholders; analysis plans to develop a family of models of BPD in neonates, leveraging previous clinical trial experience and real-world patient data is also described.

Developing a machine learning-based tool to extend the usability of the NICHD BPD Outcome Estimator to the Asian population

The NICHD BPD Outcome Estimator uses clinical and demographic data to stratify respiratory outcomes of extremely preterm infants by risk. However, the Estimator does not have an option in its pull-down menu for infants of Asian descent. We hypothesize that respiratory outcomes in extreme prematurity among various racial/ethnic groups are interconnected and therefore the Estimator can still be used to predict outcomes in infants of Asian descent. Our goal was to apply a machine learning approach to assess whether outcome prediction for infants of Asian descent is possible with information hidden in the prediction results using White, Black, and Hispanic racial/ethnic groups as surrogates. We used the three racial/ethnic options in the Estimator to obtain the probabilities of BPD outcomes for each severity category. We then combined the probability results and developed three respiratory outcome prediction models at various postmenstrual age (PMA) by a random forest algorithm. We showed satisfactory model performance, with receiver operating characteristics area under the curve of 0.934, 0.850, and 0.757 for respiratory outcomes at PMA 36, 37, and 40 weeks, respectively, in the testing data set. This study suggested an interrelationship among racial/ethnic groups for respiratory outcomes among extremely preterm infants and showed the feasibility of extending the use of the Estimator to the Asian population.

Headway and the remaining hurdles of mesenchymal stem cells therapy for bronchopulmonary dysplasia

Objective

Preterm infants are at a high risk of developing BPD. Although progression in neonatal care has improved, BPD still causes significant morbidity and mortality, which can be attributed to the limited therapeutic choices for BPD. This review discusses the potential of MSC in treating BPD as well as their hurdles and possible solutions.

Data Sources

The search for data was not limited to any sites but was mostly performed on all clinical trials available in ClinicalTrials.gov as well as on PubMed by applying the following keywords: lung injury, preterm, inflammation, neonatal, bronchopulmonary dysplasia and mesenchymal stem cells.

Study Selections

The articles chosen for this review were collectively determined to be relevant and appropriate in discussing MSC not only as a potential treatment strategy for curbing the incidence of BPD but also including insights on problems regarding MSC treatment for BPD.

Results

Clinical trials regarding the use of MSC for BPD had good results but also illustrated insights on problems to be addressed in the future regarding the treatment strategy. Despite that, the clinical trials had mostly favourable reviews.

Conclusion

With BPD existing as a constant threat and there being no permanent solutions, the idea of regenerative medicine such as MSC may prove to be a breakthrough strategy when it comes to treating BPD. The success in clinical trials led to the formulation of prospective MSC‐derived products such as PNEUMOSTEM®, and there is the possibility of a stem cell medication and permanent treatment for BPD in the near future.

Role of endoplasmic reticulum stress in impaired neonatal lung growth and bronchopulmonary dysplasia

Myeloperoxidase (MPO), oxidative stress (OS), and endoplasmic reticulum (ER) stress are increased in the lungs of rat pups raised in hyperoxia, an established model of bronchopulmonary dysplasia (BPD). However, the relationship between OS, MPO, and ER stress has not been examined in hyperoxia rat pups. We treated Sprague-Dawley rat pups with tunicamycin or hyperoxia to determine this relationship. ER stress was detected using immunofluorescence, transcriptomic, proteomic, and electron microscopic analyses. Immunofluorescence observed increased ER stress in the lungs of hyperoxic rat BPD and human BPD. Proteomic and morphometric studies showed that tunicamycin directly increased ER stress of rat lungs and decreased lung complexity with a BPD phenotype. Previously, we showed that hyperoxia initiates a cycle of destruction that we hypothesized starts from increasing OS through MPO accumulation and then increases ER stress to cause BPD. To inhibit ER stress, we used tauroursodeoxycholic acid (TUDCA), a molecular chaperone. To break the cycle of destruction and reduce OS and MPO, we used N-acetyl-lysyltyrosylcysteine amide (KYC). The fact that TUDCA improved lung complexity in tunicamycin- and hyperoxia-treated rat pups supports the idea that ER stress plays a causal role in BPD. Additional support comes from data showing TUDCA decreased lung myeloid cells and MPO levels in the lungs of tunicamycin- and hyperoxia-treated rat pups. These data link OS and MPO to ER stress in the mechanisms mediating BPD. KYC's inhibition of ER stress in the tunicamycin-treated rat pup's lung provides additional support for the idea that MPO-induced ER stress plays a causal role in the BPD phenotype. ER stress appears to expand our proposed cycle of destruction. Our results suggest ER stress evolves from OS and MPO to increase neonatal lung injury and impair growth and development. The encouraging effect of TUDCA indicates that this compound has the potential for treating BPD.

Upregulating carnitine palmitoyltransferase 1 attenuates hyperoxia-induced endothelial cell dysfunction and persistent lung injury

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a chronic lung disease in premature infants that may cause long-term lung dysfunction. Accumulating evidence supports the vascular hypothesis of BPD, in which lung endothelial cell dysfunction drives this disease. We recently reported that endothelial carnitine palmitoyltransferase 1a (Cpt1a) is reduced by hyperoxia, and that endothelial cell-specific Cpt1a knockout mice are more susceptible to developing hyperoxia-induced injury than wild type mice. Whether Cpt1a upregulation attenuates hyperoxia-induced endothelial cell dysfunction and lung injury remains unknown. We hypothesized that upregulation of Cpt1a by baicalin or L-carnitine ameliorates hyperoxia-induced endothelial cell dysfunction and persistent lung injury.

METHODS

Lung endothelial cells or newborn mice (< 12 h old) were treated with baicalin or L-carnitine after hyperoxia (50% and 95% O2) followed by air recovery.

RESULTS

We found that incubation with L-carnitine (40 and 80 mg/L) and baicalin (22.5 and 45 mg/L) reduced hyperoxia-induced apoptosis, impaired cell migration and angiogenesis in cultured lung endothelial cells. This was associated with increased Cpt1a gene expression. In mice, neonatal hyperoxia caused persistent alveolar and vascular simplification in a concentration-dependent manner. Treatment with L-carnitine (150 and 300 mg/kg) and baicalin (50 and 100 mg/kg) attenuated neonatal hyperoxia-induced alveolar and vascular simplification in adult mice. These effects were diminished in endothelial cell-specific Cpt1a knockout mice.

CONCLUSIONS

Upregulating Cpt1a by baicalin or L-carnitine ameliorates hyperoxia-induced lung endothelial cell dysfunction, and persistent alveolar and vascular simplification. These findings provide potential therapeutic avenues for using L-carnitine and baicalin as Cpt1a upregulators to prevent persistent lung injury in premature infants with BPD.

All trans-retinoic acid modulates hyperoxia-induced suppression of NF-kB-dependent Wnt signaling in alveolar A549 epithelial cells

INTRODUCTION

Despite recent advances in perinatal medicine, bronchopulmonary dysplasia (BPD) remains the most common complication of preterm birth. Inflammation, the main cause for BPD, results in arrested alveolarization. All trans-retinoic acid (ATRA), the active metabolite of Vitamin A, facilitates recovery from hyperoxia induced cell damage. The mechanisms involved in this response, and the genes activated, however, are poorly understood. In this study, we investigated the mechanisms of action of ATRA in human lung epithelial cells exposed to hyperoxia. We hypothesized that ATRA reduces hyperoxia-induced inflammatory responses in A549 alveolar epithelial cells.

METHODS

A549 cells were exposed to hyperoxia with or without treatment with ATRA, followed by RNA-seq analysis.

RESULTS

Transcriptomic analysis of A549 cells revealed ~2,000 differentially expressed genes with a higher than 2-fold change. Treatment of cells with ATRA alleviated some of the hyperoxia-induced changes, including Wnt signaling, cell adhesion and cytochrome P450 genes, partially through NF-κB signaling.

DISCUSSION/CONCLUSION

Our findings support the idea that ATRA supplementation may decrease hyperoxia-induced disruption of the neonatal respiratory epithelium and alleviate development of BPD.

Effects of early vitamin D supplementation on the prevention of bronchopulmonary dysplasia in preterm infants

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a respiratory dysfunction caused by poor lung bronchial development, which may lead to long-term lung disease, threatening the lives of children. Studies have shown that premature infants with low vitamin D are highly associated with BPD. In this study, we aim to obtain insights into whether early vitamin D supplementation could prevent BPD in preterm infants.

METHODS

A total of 112 preterm infants were randomly divided into two groups: the control and vitamin D supplementation (VD) group. The VD group received vitamin D (800 IU/day) within 48 h at birth for consecutively 28 days. The serum levels of 25(OH)D₃ and C-reactive protein (CRP), IL6, and TNF-α were measured using ELISA assay. The arterial partial pressure of oxygen (PaO₂ ) and carbon dioxide (PaCO₂ ) was measured using an i-STAT analyzer.

RESULTS

The occurrence of BPD was decreased in the VD group compared with the control. The decreased serum 25(OH)D₃ was significantly elevated by supplementation with vitamin D. In addition, the serum inflammation factors (CRP, IL6, and TNF-α) were significantly reduced by vitamin D supplementation.

CONCLUSION

We demonstrated that early vitamin D supplementation could significantly reduce BPD incidence in preterm infants. We showed that early vitamin D supplementation could significantly increase serum level of 25(OH)D₃ and reduce inflammatory response thereby preventing and reducing neonatal BPD.

LIMITATION

Firstly, a larger sample size will be needed to be included to gain a comprehensive understanding of the protective effects of vitamin D and BPD mechanistically in preterm infants. Secondly, the pathophysiological process of BPD will need to be studied. In addition, the pathways that vitamin D is responsible for, need to be further researched.

Pharmacotherapy in Bronchopulmonary Dysplasia: What Is the Evidence?

Bronchopulmonary Dysplasia (BPD) is a multifactorial disease affecting over 35% of extremely preterm infants born each year. Despite the advances made in understanding the pathogenesis of this disease over the last five decades, BPD remains one of the major causes of morbidity and mortality in this population, and the incidence of the disease increases with decreasing gestational age. As inflammation is one of the key drivers in the pathogenesis, it has been targeted by majority of pharmacological and non-pharmacological methods to prevent BPD. Most extremely premature infants receive a myriad of medications during their stay in the neonatal intensive care unit in an effort to prevent or manage BPD, with corticosteroids, caffeine, and diuretics being the most commonly used medications. However, there is no consensus regarding their use and benefits in this population. This review summarizes the available literature regarding these medications and aims to provide neonatologists and neonatal providers with evidence-based recommendations.

Postnatal diuretics, weight gain and home oxygen requirement in extremely preterm infants

OBJECTIVES

Diuretics are often given to infants with evolving/established bronchopulmonary dysplasia (BPD) with the hope of improving their pulmonary outcomes. We aimed to determine if diuretic use in preterm infants was associated with improved pulmonary outcomes, but poorer weight gain.

METHODS

An observational study over a 5 year period was undertaken of all infants born at less than 29 weeks of gestation and alive at discharge in all neonatal units in England who received consecutive diuretic use for at least 7 days. Postnatal weight gain and home supplementary oxygen requirement were the outcomes. A literature review of randomised controlled trials (RCTs) and crossover studies was undertaken to determine if diuretic usage was associated with changes in lung mechanics and oxygenation, duration of supplementary oxygen and requirement for home supplementary oxygen.

RESULTS

In the observational study, 9,457 infants survived to discharge, 44.6% received diuretics for at least 7 days. Diuretic use was associated with an increased probability of supplementary home oxygen of 0.14 and an increase in weight gain of 2.5 g/week. In the review, seven of the 10 studies reported improvements only in short term lung mechanics. There was conflicting evidence regarding whether diuretics resulted in short term improvements in oxygenation.

CONCLUSIONS

Diuretic use was not associated with a reduction in requirement for supplemental oxygen on discharge. The literature review highlighted a lack of RCTs assessing meaningful long-term clinical outcomes. Randomised trials are needed to determine the long-term risk benefit ratio of chronic diuretic use.

Lung recruitment improves the efficacy of intubation-surfactant-extubation treatment for respiratory distress syndrome in preterm neonates, a randomized controlled trial

Background

Lung recruitment is a maneuver used to decrease the length of intubation in preterm neonates. This study aimed to compare the therapeutic efficacy of lung recruitment plus intubation-surfactant-extubation (INSURE) procedure and INSURE alone for the preterm neonates with respiratory distress syndrome.

Methods

From 2017 to 2019, 184 preterm neonates (gestational age 24–32 weeks) with respiratory distress syndrome were enrolled and randomized into the lung recruitment group receiving lung recruitment (25 cm H₂O, 15 s) plus INSURE and the control group receiving INSURE only. The primary outcome was the need for mechanical ventilation (MV) within 72 h after extubation. The secondary outcomes included duration of MV, noninvasive ventilation, total oxygen therapy, hospitalization time, and complications.

Results

Compared to the control group, the lung recruitment group had a significantly lower proportion of preterm neonates requiring MV within 72 h after extubation (23% vs. 38%, P = 0.025) and pulmonary surfactant administration, as well as a shorter MV duration. There was no significant difference in the incidences of complications (all P > 0.05) and in-hospital mortality (2% vs. 4%, P = 0.4) between the lung recruitment group and control group. Multivariate logistic regression analysis demonstrated that the control group had a 2.17-time higher risk of requiring MV than the lung recruitment group (AOR: 2.17, 95% CI: 1.13–4.18; P = 0.021). Compared with infants with a normotensive mother, infants with a hypertensive mother have a 2.41-time higher risk of requiring MV (AOR: 2.41, 95% CI: 1.15–5.05; P = 0.020).

Conclusion

Lung recruitment plus INSURE can reduce the need for MV within 72 h after extubation and did not increase the incidence of complications and mortality.

Trial registration

Chinese Clinical Trial Registry ChiCTR1800020125, retrospectively registered on December 15, 2018.

Role of the LRP1-pPyk2-MMP9 pathway in hyperoxia-induced lung injury in neonatal rats

OBJECTIVES

To study the role of the low-density lipoprotein receptor-related protein 1 (LRP1)-proline-rich tyrosine kinase 2 phosphorylation (pPyk2)-matrix metalloproteinases 9 (MMP9) pathway in hyperoxia-induced lung injury in neonatal rats.

METHODS

A total of 16 neonatal rats were randomly placed in chambers containing room air (air group) or 95% medical oxygen (hyperoxia group) immediately after birth, with 8 rats in each group. All of the rats were sacrificed on day 8 of life. Hematoxylin and eosin staining was used to observe the pathological changes of lung tissue. ELISA was used to measure the levels of soluble LRP1 (sLRP1) and MMP9 in serum and bronchoalveolar lavage fluid (BALF). Western blot was used to measure the protein expression levels of LRP1, MMP9, Pyk2, and pPyk2 in lung tissue. RT-PCR was used to measure the mRNA expression levels of LRP1 and MMP9 in lung tissue.

RESULTS

The hyperoxia group had significantly higher levels of sLRP1 and MMP9 in serum and BALF than the air group (P<0.05). Compared with the air group, the hyperoxia group had significant increases in the protein expression levels of LRP1, MMP9, and pPyk2 in lung tissue (P<0.05). The hyperoxia group had significantly higher relative mRNA expression levels of LRP1 and MMP9 in lung tissue than the air group (P<0.05).

CONCLUSIONS

The activation of the LRP1-pPyk2-MMP9 pathway is enhanced in hyperoxia-induced lung injury in neonatal rats, which may be involved in the pathogenesis of bronchopulmonary dysplasia.

Mesenchymal Stem Cells: Potential Therapeutic Prospect of Paracrine Pathways in Neonatal Infection

Infection is the leading cause of admission and mortality in neonatal intensive care units. Immature immune function and antibiotic resistance make the treatment more difficult. However, there is no effective prevention for it. Recently, more and more researches are focusing on stem cell therapy, especially mesenchymal stem cells (MSCs); their potential paracrine effect confer MSCs with a major advantage to treat the immune and inflammatory disorders associated with neonatal infection. In this review, we summarize the basal properties and preclinical evidence of MSCs and explore the potential mechanisms of paracrine factors of MSCs for neonatal infection.

Dexamethasone Alters Tracheal Aspirate T-Cell Cytokine Production in Ventilated Preterm Infants

Postnatal corticosteroids improve respiratory status and facilitate respiratory support weaning in preterm infants with bronchopulmonary dysplasia (BPD). Older literature describes characteristic cytokine profiles in tracheal aspirates (TA) of BPD patients which are altered with corticosteroids. Corticosteroids also influence peripheral blood T-cell presence. However, little is known regarding TA T-cell phenotype and cytokine production before or after exogenous corticosteroids. We hypothesized that postnatal dexamethasone alters the TA T-cell cytokine profiles of preterm infants. TA samples were collected from 14 infants born from 23 0/7 to 28 6/7 weeks who were mechanically ventilated for at least 14 days. Samples were collected up to 72 h before a ten-day dexamethasone course and again 1 to 3 calendar days after dexamethasone initiation. The primary outcome was change in T cell populations present in TA and their intracellular cytokine profile after dexamethasone treatment, ascertained via flow cytometry. Following dexamethasone treatment, there were significant decreases in respiratory severity score (RSS), percent CD4+IL-6+ cells, CD8+IL-6+ cells, CXCR3+IL-6+ cells, and CXCR3+IL-2+ cells and total intracellular IFN-γ in TA. RSS significantly correlated with TA percent CD4+IL-6+ cells. To our knowledge, this is the first study demonstrating that dexamethasone reduced T-cell IL-6 and this reduction was associated with improved RSS in pre-term infants with evolving BPD.

Use of diuretics in the neonatal period

The use of diuretics is extremely frequent in sick neonates, the more so in very premature newborn infants. The use of diuretics in patients whose kidney function is immature necessitates a thorough knowledge of renal developmental physiology and pathophysiology. This review presents the basic aspects of body fluid homeostasis in the neonate, discusses the development of kidney function, and describes the mechanisms involved in electrolyte and water reabsorption along the nephron. Diuretics are then classified according to the site of their action on sodium reabsorption. The use of diuretics in sodium-retaining states, in oliguric states, in electrolyte disorders, and in arterial hypertension, as well as in a few specific disorders, is presented. Common and specific adverse effects are discussed. Recommended dosages for the main diuretics used in the neonatal period are given. New developments in diuretic therapy are briefly mentioned.

Metabolic dysregulation in bronchopulmonary dysplasia: Implications for identification of biomarkers and therapeutic approaches

Bronchopulmonary dysplasia (BPD) is a common chronic lung disease in premature infants. Accumulating evidence shows that dysregulated metabolism of glucose, lipids and amino acids are observed in premature infants. Animal and cell studies demonstrate that abnormal metabolism of these substrates results in apoptosis, inflammation, reduced migration, abnormal proliferation or senescence in response to hyperoxic exposure, and that rectifying metabolic dysfunction attenuates neonatal hyperoxia-induced alveolar simplification and vascular dysgenesis in the lung. BPD is often associated with several comorbidities, including pulmonary hypertension and neurodevelopmental abnormalities, which significantly increase the morbidity and mortality of this disease. Here, we discuss recent progress on dysregulated metabolism of glucose, lipids and amino acids in premature infants with BPD and in related in vivo and in vitro models. These findings suggest that metabolic dysregulation may serve as a biomarker of BPD and plays important roles in the pathogenesis of this disease. We also highlight that targeting metabolic pathways could be employed in the prevention and treatment of BPD.

The Role of LncRNA H19 in MAPK Signaling Pathway Implicated in the Progression of Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD), also known as neonatal chronic lung disease, is an important cause of respiratory illness in preterm newborns that results in significant morbidity and mortality. Long noncoding RNAs (lncRNAs) have been discovered with many biological functions. However, the role of lncRNAs in the pathogenesis of BPD remains poorly understood. Here, we established a mouse lung injury model that mimicked human BPD. Subsequently, we found the lncRNA H19 expression level was significantly increased in BPD compared with normal lung tissues using quantitative real-time polymerase chain reaction. Next, we observed that overexpression of lncRNA H19 enhanced mitogen-activated protein kinase (MAPK) signaling pathway. In addition, we also found that dysfunction of lncRNA H19 altered the expression of inflammatory factors. Thus, our study validates that lncRNA H19 contributes to the progression of BPD by regulating MAPK signaling pathway, which could be used as a potential target for treating BPD.

Therapeutic Effects of Mesenchymal Stromal Cell-Derived Small Extracellular Vesicles in Oxygen-Induced Multi-Organ Disease: A Developmental Perspective

Despite major advances in neonatal intensive care, infants born at extremely low birth weight still face an increased risk for chronic illness that may persist into adulthood. Pulmonary, retinal, and neurocognitive morbidities associated with preterm birth remain widespread despite interventions designed to minimize organ dysfunction. The design of therapeutic applications for preterm pathologies sharing common underlying triggers, such as fluctuations in oxygen supply or in the inflammatory state, requires alternative strategies that promote anti-inflammatory, pro-angiogenic, and trophic activities—ideally as a unitary treatment. Mesenchymal stem/stromal cell-derived extracellular vesicles (MEx) possess such inherent advantages, and they represent a most promising treatment candidate, as they have been shown to contribute to immunomodulation, homeostasis, and tissue regeneration. Current pre-clinical studies into the MEx mechanism of action are focusing on their restorative capability in the context of preterm birth-related pathologies, albeit not always with a multisystemic focus. This perspective will discuss the pathogenic mechanisms underlying the multisystemic lesions resulting from early-life disruption of normal physiology triggered by high oxygen exposures and pro-inflammatory conditions and introduce the application of MEx as immunomodulators and growth-promoting mediators for multisystem therapy.

Hypochloremia Secondary to Diuretics in Preterm Infants: Should Clinicians Pay Close Attention?

Diuretic therapy, commonly used in the newborn intensive care unit, is associated with a variety of electrolyte abnormalities such as hyponatremia, hypokalemia, and hypochloremia. Hypochloremia, often ignored, is associated with significant morbidities and increased mortality in infants and adults. Clinicians respond in a reflex manner to hyponatremia than to hypochloremia. Hypochloremia is associated with nephrocalcinosis, hypochloremic alkalosis, and poor growth. Besides, the diuretic resistance associated with hypochloremia makes maintaining chloride levels in the physiological range even more logical. Since sodium supplementation counters the renal absorption of calcium and lack of evidence for spironolactone role in diuretic therapy for bronchopulmonary dysplasia (BPD), alternate chloride supplements such as potassium or arginine chloride may need to be considered in the management of hypochloremia due to diuretic therapy. In this review, we have summarized the current literature on hypochloremia secondary to diuretics and suggested a pragmatic approach to hypochloremia in preterm infants.

Bronchopulmonary dysplasia predicted at birth by artificial intelligence

Aim

To develop a fast bedside test for prediction and early targeted intervention of bronchopulmonary dysplasia (BPD) to improve the outcome.

Methods

In a multicentre study of preterm infants with gestational age 24‐31 weeks, clinical data present at birth were combined with spectral data of gastric aspirate samples taken at birth and analysed using artificial intelligence. The study was designed to develop an algorithm to predict development of BPD. The BPD definition used was the consensus definition of the US National Institutes of Health: Requirement of supplemental oxygen for at least 28 days with subsequent assessment at 36 weeks postmenstrual age.

Results

Twenty‐six (43%) of the 61 included infants developed BPD. Spectral data analysis of the gastric aspirates identified the most important wave numbers for classification and surfactant treatment, and birth weight and gestational age were the most important predictive clinical data. By combining these data, the resulting algorithm for early diagnosis of BPD had a sensitivity of 88% and a specificity of 91%.

Conclusion

A point‐of‐care test to predict subsequent development of BPD at birth has been developed using a new software algorithm allowing early targeted intervention of BPD which could improve the outcome.

A shift from glycolytic and fatty acid derivatives toward one-carbon metabolites in the developing lung during transitions of the early postnatal period

During postnatal lung development, metabolic changes that coincide with stages of alveolar formation are poorly understood. Responding to developmental and environmental factors, metabolic changes can be rapidly and adaptively altered. The objective of the present study was to determine biological and technical determinants of metabolic changes during postnatal lung development. Over 118 metabolic features were identified by liquid chromatography with tandem mass spectrometry (LC-MS/MS, Sciex QTRAP 5500 Triple Quadrupole). Biological determinants of metabolic changes were the transition from the postnatal saccular to alveolar stages and exposure to 85% hyperoxia, an environmental insult. Technical determinants of metabolic identification were brevity and temperature of harvesting, both of which improved metabolic preservation within samples. Multivariate statistical analyses revealed the transition between stages of lung development as the period of major metabolic alteration. Of three distinctive groups that clustered by age, the saccular stage was identified by its enrichment of both glycolytic and fatty acid derivatives. The critical transition between stages of development were denoted by changes in amino acid derivatives. Of the amino acid derivatives that significantly changed, a majority were linked to metabolites of the one-carbon metabolic pathway. The enrichment of one-carbon metabolites was independent of age and environmental insult. Temperature was also found to significantly influence the metabolic levels within the postmortem sampled lung, which underscored the importance of methodology. Collectively, these data support not only distinctive stages of metabolic change but also highlight amino acid metabolism, in particular one-carbon metabolites as metabolic signatures of the early postnatal lung.

Description of a Nutrition Screening and Assessment Tool and Associations with Clinical Outcomes in Preterm Newborns

BACKGROUND

Preterm newborns have higher nutrition risk and mortality. Nutrition risk screening enables early intervention. This article evaluates a nutrition screening tool in a neonatal intensive care unit (NICU).

METHOD

Retrospective longitudinal study of preterm newborns (aged <37 weeks) in a NICU in Brazil from May 2018 to January 2019. Weight, length, and head circumference (HC) were analyzed. Nutrition screening was defined by care levels (CLs). Outcomes analyzed were bronchopulmonary dysplasia (BPD), peri-intraventricular hemorrhage (PIVH), retinopathy of prematurity (ROP), late sepsis, length of stay, mortality, and time receiving enteral and parenteral nutrition.

RESULTS

Data on 110 newborns were studied, with median gestational age 34 (31-35) weeks, mean weight 1914.92 g (±657.7), length 42.2 cm (±4.45), and HC 29.9 cm (±2.97). Most (82.7%) of them were adequate for gestational age. Screening classifications were 41.8% (n = 46) at CL 2, 41.8% (n = 46) at CL 3, and 16.4% (n = 18) at CL 4. CL 3 and CL 4 patients had higher frequencies of BPD (P = .003), ROP (P = .027), and PIVH (P = .006) and longer enteral time (P < .001) and length of stay (P < .001). All mortality occurred in CL 4 patients (P < .001).

CONCLUSIONS

CL 3 and CL 4 patients had more BPD, ROP, PIVH, and mortality and longer enteral nutrition. Hospital stay was longer for CL ≥3 than CL 2 patients. Patients classified as CL 3 and CL 4 by the nutrition screening tool may have higher nutrition risk.

Comparison of Multivariable Logistic Regression and Machine Learning Models for Predicting Bronchopulmonary Dysplasia or Death in Very Preterm Infants

Bronchopulmonary dysplasia (BPD) is the most prevalent and clinically significant complication of prematurity. Accurate identification of at-risk infants would enable ongoing intervention to improve outcomes. Although postnatal exposures are known to affect an infant's likelihood of developing BPD, most existing BPD prediction models do not allow risk to be evaluated at different time points, and/or are not suitable for use in ethno-diverse populations. A comprehensive approach to developing clinical prediction models avoids assumptions as to which method will yield the optimal results by testing multiple algorithms/models. We compared the performance of machine learning and logistic regression models in predicting BPD/death. Our main cohort included infants <33 weeks' gestational age (GA) admitted to a Canadian Neonatal Network site from 2016 to 2018 (n = 9,006) with all analyses repeated for the <29 weeks' GA subcohort (n = 4,246). Models were developed to predict, on days 1, 7, and 14 of admission to neonatal intensive care, the composite outcome of BPD/death prior to discharge. Ten-fold cross-validation and a 20% hold-out sample were used to measure area under the curve (AUC). Calibration intercepts and slopes were estimated by regressing the outcome on the log-odds of the predicted probabilities. The model AUCs ranged from 0.811 to 0.886. Model discrimination was lower in the <29 weeks' GA subcohort (AUCs 0.699-0.790). Several machine learning models had a suboptimal calibration intercept and/or slope (k-nearest neighbor, random forest, artificial neural network, stacking neural network ensemble). The top-performing algorithms will be used to develop multinomial models and an online risk estimator for predicting BPD severity and death that does not require information on ethnicity.

A clinical study on plasma biomarkers for deciding the use of adjuvant corticosteroid therapy in bronchopulmonary dysplasia of premature infants

Objective: The study was designed to investigate some plasma markers which help us to decide the use of adjuvant corticosteroid therapy in bronchopulmonary dysplasia (BPD) of premature infants. Methods: Thirty BPD infants were treated by dexamethasone. Among these cases, dexamethasone was significant effective in 10 cases, and no significant effective in 20 cases. These patients were divided into two groups as the significant effect (SE) group (n=10) and the non-significant effect (NE) group (n=20) according to the curative effect of dexamethasone. Fifteen non-BPD infants with gestational age and gender matching were selected as the control group. Plasma samples before and after dexamethasone treatment were collected from three infants chosen randomly from SEG for the data-independent acquisition (DIA) analysis. ELISA was further used to detect the levels of differential proteins LRP1 and S100A8 in all individuals, including SE, NE and control groups. Results: DIA analysis results showed that after dexamethasone treatment, there were a total of 52 plasma proteins that showed significant differences, of which 43 proteins were down-regulated and 9 proteins were up-regulated. LRP1 and S100A8 were two plasma proteins that were significantly changed after dexamethasone treatment. Compared with the control group, plasma LRP1 was significantly increased in BPD. Interestingly, the plasma concentration of LRP1 in the NE group was significantly higher than that in the SE group. S100A8, as an indicator of plasma inflammation, was significantly higher in BPD than the control group. Unlike LRP1, there was no significantly difference between the SE and NE group (P=0.279) before dexamethasone treatment. Conclusion: Elevated plasma LRP1 and S100A8 in BPD infants are two indicators that correlated with the efficacy of dexamethasone, and might be used as biomarkers for deciding the use of adjuvant corticosteroids therapy in the BPD.

Exogenous Surfactant as a Pulmonary Delivery Vehicle for Budesonide In Vivo

Background

Lung inflammation is associated with many respiratory conditions. Consequently, anti-inflammatory medications, like glucocorticoids, have become mainstay intrapulmonary therapeutics. However, their effectiveness for treating inflammation occurring in the alveolar regions of the lung is limited by suboptimal delivery. To improve the pulmonary distribution of glucocorticoids, such as budesonide to distal regions of the lung, exogenous surfactant has been proposed as an ideal delivery vehicle for such therapies. It was therefore hypothesized that fortifying an exogenous surfactant (BLES) with budesonide would enhance efficacy for treating pulmonary inflammation in vivo.

Methods

An intratracheal instillation of heat-killed bacteria was used to elicit an inflammatory response in the lungs of male and female rats. Thirty minutes after this initial instillation, either budesonide or BLES combined with budesonide was administered intratracheally. To evaluate the efficacy of surfactant delivery, various markers of inflammation were measured in the bronchoalveolar lavage and lung tissue.

Results

Although budesonide exhibited anti-inflammatory effects when administered alone, delivery with BLES enhanced those effects by lowering the lavage neutrophil counts and myeloperoxidase activity in lung tissue. Combining budesonide with BLES was also shown to reduce several other pro-inflammatory mediators. These results were shown across both sexes, with no observed sex differences.

Conclusion

Based on these findings, it was concluded that exogenous surfactant can enhance the delivery and efficacy of budesonide in vivo.

Allogeneic administration of human umbilical cord-derived mesenchymal stem/stromal cells for bronchopulmonary dysplasia: preliminary outcomes in four Vietnamese infants

Background

Bronchopulmonary dysplasia (BPD) is a severe condition in premature infants that compromises lung function and necessitates oxygen support. Despite major improvements in perinatal care minimizing the devastating effects, BPD remains the most frequent complication of extreme preterm birth. Our study reports the safety of the allogeneic administration of umbilical cord-derived mesenchymal stem/stromal cells (allo-UC-MSCs) and the progression of lung development in four infants with established BPD.

Methods

UC tissue was collected from a healthy donor, followed by propagation at the Stem Cell Core Facility at Vinmec Research Institute of Stem Cell and Gene Technology. UC-MSC culture was conducted under xeno- and serum-free conditions. Four patients with established BPD were enrolled in this study between May 25, 2018, and December 31, 2018. All four patients received two intravenous doses of allo-UC-MSCs (1 million cells/kg patient body weight (PBW) per dose) with an intervening interval of 7 days. Safety and patient conditions were evaluated during hospitalization and at 7 days and 1, 6 and 12 months postdischarge.

Results

No intervention-associated severe adverse events or prespecified adverse events were observed in the four patients throughout the study period. At the time of this report, all patients had recovered from BPD and were weaned off of oxygen support. Chest X-rays and CT scans confirmed the progressive reductions in fibrosis.

Conclusions

Allo-UC-MSC administration is safe in preterm infants with established BPD.

Trial registration This preliminary study was approved by the Vinmec International Hospital Ethics Board (approval number: 88/2019/QĐ-VMEC; retrospectively registered March 12, 2019).

Amniotic fluid and breast milk: a rationale for breast milk stem cell therapy in neonatal diseases

Amniotic fluid and breast milk play important roles in structural development throughout fetal growth and infancy. Given their significance in physical maturation, many studies have investigated the therapeutic and protective roles of amniotic fluid and breast milk in neonatal diseases. Of particular interest to researchers are stem cells found in the two fluids. These stem cells have been investigated due to their ability to self-replicate, differentiate, reduce tissue damage, and their expression of pluripotent markers. While amniotic fluid stem cells have received some attention regarding their ability to treat neonatal diseases, breast milk stem cells have not been investigated to the same extent given the recency of their discovery. The purpose of this review is to compare the functions of amniotic fluid, breast milk, and their stem cells to provide a rationale for the use of breast milk stem cells as a therapy for neonatal diseases. Breast milk stem cells present as an important tool for treating neonatal diseases given their ability to reduce inflammation and tissue damage, as well as their multilineage differentiation potential, easy accessibility, and ability to be used in disease modelling.

Advancing Therapeutic Development for Pulmonary Morbidities Associated with Preterm Birth

Chronic pulmonary and respiratory conditions associated with preterm birth are incompletely characterized, complicating long-term treatment and development of more effective therapies. Stakeholders face challenges in the development of validated, clinically meaningful endpoints that adequately measure morbidities and predict or represent health outcomes for preterm neonates. We propose in this paper a research agenda, informed by the input of experts from a 2018 workshop we convened on this topic, to advance endpoint and treatment development. We discuss the necessity of further evaluation of existing endpoints and the improved characterization of disease endotypes. We also discuss key steps to the development of optimized short- and long-term endpoints that can be linked to meaningful health outcomes. Finally, we discuss the importance of limiting variability in data collection and the application of new clinical trial endpoints as well as the critical nature of multi-stakeholder collaboration to advancing therapeutic development for this vulnerable patient population.

Stem-cell therapy for bronchopulmonary dysplasia

PURPOSE OF REVIEW

Clinical trials of mesenchymal stem/stromal cell (MSC) therapy for bronchopulmonary dysplasia (BPD) are underway. A thorough understanding of the preclinical work that underpins these trials is critical for neonatal practitioners to properly evaluate them.

RECENT FINDINGS

Significant progress has been made in understanding that MSCs have anti-inflammatory and proangiogenic effects, and that these can be mediated by the noncellular exosome fraction of MSCs.

SUMMARY

In rodent hyperoxia models of BPD, MSCs have a proangiogenic effect mediated largely by vascular endothelial growth factor and shift the balance of endogenous lung cells from a proinflammatory to a prohealing phenotype. MSC-derived exosomes can recapitulate these effects.

Attenuation of Hyperoxic Lung Injury in Newborn Thioredoxin-1-Overexpressing Mice through the Suppression of Proinflammatory Cytokine mRNA Expression

The role of thioredoxin-1 (TRX), a small redox-active protein with antioxidant effects, during hyperoxic lung injury in newborns remains undetermined. We investigated TRX impact on hyperoxic lung injury in newborn TRX transgenic (TRX-Tg) and wildtype (WT) mice exposed to 21% or 95% O₂ for four days, after which some mice were allowed to recover in room air for up to 14 days. Lung morphology was assessed by hematoxylin/eosin and elastin staining, as well as immunostaining for macrophages. The gene expression levels of proinflammatory cytokines were evaluated using quantitative real-time polymerase chain reaction. During recovery from hyperoxia, TRX-Tg mice exhibited an improved mean linear intercept length and increased number of secondary septa in lungs compared with the WT mice. Neonatal hyperoxia enhanced the mRNA expression levels of proinflammatory cytokines in the lungs of both TRX-Tg and WT mice. However, interleukin-6, monocyte chemoattractant protein-1, and chemokine (C-X-C motif) ligand 2 mRNA expression levels were reduced in the lungs of TRX-Tg mice compared with the WT mice during recovery from hyperoxia. Furthermore, TRX-Tg mice exhibited reduced macrophage infiltration in lungs during recovery. These results suggest that in newborn mice TRX ameliorates hyperoxic lung injury during recovery likely through the suppression of proinflammatory cytokines.

Proteomic analysis of sex differences in hyperoxic lung injury in neonatal mice

Sex-specific differences in the severity of bronchopulmonary dysplasia (BPD) are due to different susceptibility to hyperoxic lung injury, but the mechanism is unclear. In this study, neonatal male and female mouse pups (C57BL/6J) were exposed to hyperoxia and lung tissues were excised on postnatal day 7 for histological analysis and tandem mass tags proteomic analysis. We found that the lung sections from the male mice following postnatal hyperoxia exposure had increased alveolar simplification, significant aberrant pulmonary vascularization and arrest in angiogenesis compared with females. Comparison of differentially expressed proteins revealed 377 proteins unique to female and 425 unique to male as well as 750 proteins in both male and female. Bioinformatics analysis suggested that several differentially expressed proteins could contribute to the differences in sex-specific susceptibility to hyperoxic lung injury. Our results may help identify sex-specific biomarkers and therapeutic targets of BPD.

Inhibition of microRNA-29a alleviates hyperoxia-induced bronchopulmonary dysplasia in neonatal mice via upregulation of GAB1

Background

The main features of bronchopulmonary dysplasia (BPD) are alveolar simplification, pulmonary growth arrest, and abnormal lung function. Multiple studies have highlighted microRNA-29 (miR-29) as a potential biomarker for lung diseases and cancers. Upregulation of miR-29a has been known to downregulate GRB2-associated-binding protein 1 (GAB1), which is often highly expressed in the lung. The current study was designed to investigate the potential role of miR-29a in hyperoxia-induced BPD by targeting GAB1 in a neonatal mouse model.

Methods

The expression of miR-29a and GAB1 in lung tissues of neonatal mice with hyperoxia-induced BPD and mouse alveolar epithelial cells (MLE-12) was determined using RT-qPCR and western blot analysis. Subsequently, the relationship between miR-29a and GAB1 was verified using in silico analysis. In order to assess the effects of miR-29a or GAB1 on BPD, the pathological characteristics of alveoli, as well as proliferation and apoptosis of cells were measured through gain- and loss-of-function studies.

Results

Upregulation of miR-29a and downregulation of GAB1 were evident in both lung tissues and MLE-12 cells following BPD modeling. GAB1 was a direct target gene of miR-29a. Inhibition of miR-29a and overexpression of GAB1 were shown to alleviate lung injury, promote cell proliferation and inhibit apoptosis but reduce chord length in lung tissues of neonatal mice following hyperoxia-induced BPD modeling.

Conclusion

Altogether, down-regulation of miR-29a can potentially elevate GAB1 expression, reducing cell apoptosis and stimulating proliferation, ultimately retarding the development of BPD in mice. This study highlights the potential of a promising new target for preventing BPD.

Erythropoietin treatment is associated with a reduction in moderate to severe bronchopulmonary dysplasia in preterm infants. A regional retrospective study

Erythropoietin treatment is associated with a reduction in moderate to severe bronchopulmonary dysplasia in preterm infants. A regional retrospective study.

OBJECTIVE

To determine whether premature infants treated with erythropoietin (Epo) in the neonatal period for anemia had a lower incidence of bronchopulmonary dysplasia (BPD), defined as oxygen need at 36 weeks postmenstrual age, and lower rehospitalization rates in the first year of life than infants not exposed.

METHODS

Retrospective study of a population of infants born at 23 to 32 weeks gestational age, between January 2009 and December 2014, with birthweight ≤1500 g. Patient characteristics, and risk factors for BPD were compared between patients who received erythropoietin, and those not exposed. To examine the association between the outcomes of BPD at 36 weeks PMA, rehospitalization, and erythropoietin treatment, we performed a propensity score (PS) analysis using inverse probability of treatment weighted (IPTW) approach. For comparison, we conducted a logistic regression adjusting for the same covariates used to generate PS using the original population.

RESULTS

The study population included 1821 preterm infants: 928 received Epo and 893 did not. Epo treatment was associated with a reduction in BPD (18.8% versus 25.9%, p < 0.01) at 36 weeks PMA and reduced median length of stay with lowest BPD rate with Epo initiation before 2 weeks of age. There was no difference in rehospitalization rates in the first year of life.

CONCLUSION

Erythropoietin treatment was associated with a reduction in BPD but not in rehospitalization rate in the first year of life.

Decorin Secreted by Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Induces Macrophage Polarization via CD44 to Repair Hyperoxic Lung Injury

Bronchopulmonary dysplasia (BPD), caused by hyperoxia in newborns and infants, results in lung damage and abnormal pulmonary function. However, the current treatments for BPD are steroidal and pharmacological therapies, which cause neurodevelopmental impairment. Treatment with umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) is an efficient alternative approach. To prevent pulmonary inflammation in BPD, this study investigated the hypothesis that a key regulator was secreted by MSCs to polarize inflammatory macrophages into anti-inflammatory macrophages at inflammation sites. Lipopolysaccharide-induced macrophages co-cultured with MSCs secreted low levels of the inflammatory cytokines, IL-8 and IL-6, but high levels of the anti-inflammatory cytokine, IL-10. Silencing decorin in MSCs suppressed the expression of CD44, which mediates anti-inflammatory activity in macrophages. The effects of MSCs were examined in a rat model of hyperoxic lung damage. Macrophage polarization differed depending on the levels of decorin secreted by MSCs. Moreover, intratracheal injection of decorin-silenced MSCs or MSCs secreting low levels of decorin confirmed impaired alveolarization of damaged lung tissues by down-regulation of decorin. In tissues, a decrease in the anti-inflammatory macrophage marker, CD163, was observed via CD44. Thus, we identified decorin as a key paracrine factor, inducing macrophage polarization via CD44, a master immunoregulator in mesenchymal stem cells.

Phenotypic overlap in neonatal respiratory morbidity following preterm premature rupture of membranes versus spontaneous preterm labor

BACKGROUND

Bronchopulmonary dysplasia (BPD), a major source of morbidity in premature neonates, has been associated with intrauterine infection and preterm birth. Both preterm premature rupture of membranes (PPROM) and spontaneous preterm labor (sPTL) are linked with intrauterine inflammation. Whether PPROM and sPTL, as two phenotypic categories of preterm birth, are associated with exposure to different degrees and durations of inflammation that might impact fetal lung development is unknown. PPROM may be associated with longer latency until delivery, which is beneficial for neonatal mortality, but may impart greater injury risk to the developing fetal lungs. It is unknown if PPROM is associated with a greater risk of adverse neonatal respiratory outcomes than sPTL.

OBJECTIVE

The objective of this study was to determine if PPROM imparts a differentially greater risk for neonatal BPD than sPTL. A secondary objective was to determine if PPROM was associated with a greater risk of adverse neonatal respiratory outcomes other than BPD and whether gestational latency following PPROM or sPTL diagnosis constitutes a risk factor for fetal lung injury.

STUDY DESIGN

We conducted a retrospective secondary analysis of a large cohort of women at risk for spontaneous preterm birth, who were originally enrolled in a randomized controlled trial of magnesium sulfate versus placebo examining neuroprotection. For our study, we included women with a singleton pregnancy complicated by PPROM or sPTL and delivery between 24 and 34 weeks gestational age. Cases with multiple gestation, congenital anomalies, maternal seropositivity for human immunodeficiency virus, or hypertensive diseases of pregnancy (including preeclampsia) were excluded. The primary outcome was BPD. Secondary outcomes were respiratory distress syndrome (RDS), transient tachypnea of the newborn (TTN), requirement for mechanical ventilation, pneumonia, neonatal sepsis, fetal or neonatal death, and a composite of adverse neonatal respiratory outcomes including (BPD, pneumonia, RDS, and TTN). Statistical analyses included chi-square, Student's t-test and logistic and multiple regression.

RESULTS

A total of 1729 women were included in this analysis including 1554 with PPROM and 175 with sPTL. Women in the PPROM group were more likely to be older, not of Hispanic race, married, more educated, have smoked during pregnancy and have a greater body mass index. The BPD rate was not significantly different following PPROM versus sPTL. Neonates in the PPROM group experienced a lower rate of pneumonia (p = .001), neonatal sepsis (p = .009) and patent ductus arterious (PDA) requiring either medical or surgical therapy (p < .001) than neonates in the sPTL group. Chorioamnionitis was more common in the PPROM group (p = .008) than the sPTL group. After multivariable logistic regression with BPD or composite of adverse neonatal respiratory outcomes as the dependent outcomes, and controlling for gestational age at delivery, maternal smoking history, duration of mechanical ventilation and RDS, there was no significant difference between PPROM and sPTL.

CONCLUSIONS

BPD rates were not significantly different in neonates born to women following PPROM versus sPTL. However, PPROM was associated with lower rates of pneumonia, neonatal sepsis, and PDA requiring therapy in the univariate analysis, but not the multivariate analysis. Neonatal respiratory outcomes may have a similar phenotypic overlap regardless of whether preterm birth follows PPROM or sPTL.