Inhalation or instillation of steroids for the prevention of bronchopulmonary dysplasia

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.

Neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio are early predictors of bronchopulmonary dysplasia

To determine whether neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are correlated with bronchopulmonary dysplasia (BPD) on the first day of prematurity and to help with early warning, identification, and intervention in the development of BPD. From January 2017 to June 2022, newborns who were diagnosed with BPD conducted a retrospective cohort study. Complete blood cells were measured within the first 24 hours of life in preterm neonates of 32 gestational weeks with BPD as the observation group and non-BPD infants as the control group. In all groups, the NLR and PLR levels were measured. Both univariate and multivariate logistic regression analyses were used to evaluate the data. In this research 76 cases of non-BPD and 48 cases of BPD were used as controls. Compared with the non-BPD group, the NLR and PLR levels were considerably higher in the BPD group. Logistic regression analysis suggested that NLR and PLR were independent risk factors for BPD (OR [odds ratio]: 3.786; 95% CI [confidence interval]: 1.75-8.16; P < .05; OR: 3.391; 95% CI: 1.85-28.78; P < .05). The findings may demonstrate that higher NLR and PLR are independently and significantly associated with the development of BPD.

Molecular Insight into the Therapeutic Effects of Stem Cell-Derived Exosomes in Respiratory Diseases and the Potential for Pulmonary Delivery

Respiratory diseases are the cause of millions of deaths annually around the world. Despite the recent growth of our understanding of underlying mechanisms contributing to the pathogenesis of lung diseases, most therapeutic approaches are still limited to symptomatic treatments and therapies that only delay disease progression. Several clinical and preclinical studies have suggested stem cell (SC) therapy as a promising approach for treating various lung diseases. However, challenges such as the potential tumorigenicity, the low survival rate of the SCs in the recipient body, and difficulties in cell culturing and storage have limited the applicability of SC therapy. SC-derived extracellular vesicles (SC-EVs), particularly SC-derived exosomes (SC-Exos), exhibit most therapeutic properties of stem cells without their potential drawbacks. Similar to SCs, SC-Exos exhibit immunomodulatory, anti-inflammatory, and antifibrotic properties with the potential to be employed in the treatment of various inflammatory and chronic respiratory diseases. Furthermore, recent studies have demonstrated that the microRNA (miRNA) content of SC-Exos may play a crucial role in the therapeutic potential of these exosomes. Several studies have investigated the administration of SC-Exos via the pulmonary route, and techniques for SCs and SC-Exos delivery to the lungs by intratracheal instillation or inhalation have been developed. Here, we review the literature discussing the therapeutic effects of SC-Exos against respiratory diseases and advances in the pulmonary route of delivery of these exosomes to the damaged tissues.

A Randomized Clinical Trial of Intratracheal Administration of Surfactant and Budesonide Combination in Comparison to Surfactant for Prevention of Bronchopulmonary Dysplasia

Objectives

Bronchopulmonary dysplasia (BPD) remains a major problem in preterm infants occurring in up to 50% of infants born at < 28 weeks gestational age. Inflammation plays an important role in the pathogenesis of BPD. This study was conducted to evaluate the efficacy of intratracheal budesonide administration in combination with a surfactant in preventing BPD in preterm infants.

Methods

In a randomized clinical trial, 128 preterm infants at < 30 weeks gestational age and weighing < 1500 g at birth were studied. All had respiratory distress syndrome (RDS) and needed surfactant replacement therapy. They were randomly allocated into two groups; surfactant group (n = 64) and surfactant + budesonide group 
(n = 64). Neonates in the surfactant group received intratracheal Curosurf 200 mg/kg/dose. Patients in the surfactant + budesonide group were treated with intratracheal instillation of a mixed suspension of budesonide 0.25 mg/kg and Curosurf 200 mg/kg/dose. Neonates were followed untill discharge for the primary outcome which was BPD and secondary outcomes including sepsis, patent ductus arteriosus (PDA), retinopathy of prematurity (ROP), and necrotizing enterocolitis (NEC).

Results

The mean gestational age and birth weight of the studied neonates were 28.3±1.6 weeks and 1072.0±180.0 g, respectively. The demographic characteristics and RDS score were similar in the two groups. BPD occurred in 24 (37.5%) neonates in the surfactant + budesonide group and 38 (59.4%) neonates in surfactant group, p = 0.040. Hospital stay was 29.7±19.2 days (median = 30 days) in the surfactant group and 23.3±18.1 days (median = 20 days) in the surfactant + budesonide group, p = 0.050. The rates of sepsis, PDA, ROP, and NEC were not significantly different in the two groups.

Conclusions

The use of budesonide in addition to surfactant for rescue therapy of RDS in preterm infants decreases the incidence of BPD and duration of respiratory support significantly. Large adequately powered clinical trials with long-term safety assessments are needed to confirm our findings before its routine use can be recommended.

The efficacy of intratracheal administration of surfactant and budesonide combination in the prevention of bronchopulmonary dysplasia

Background:

Bronchopulmonary dysplasia (BPD) remains a major problem in preterm infants that occurs in up to 50% of preterm infants. The inflammation plays an important role in its pathogenesis. This study was conducted to evaluate the efficacy intratracheal budesonide administration in combination with surfactant in the prevention of BPD in preterm infants.

Materials and Methods:

In a randomized controlled clinical trial, 128 preterm infants with gestation age <30 weeks and birth weight <1250 g who had respiratory distress syndrome (RDS) and need surfactant replacement therapy were studied. They randomly allocated into two groups, surfactant group (n = 64) and surfactant + budesonide group (n = 64). Patients were followed till discharge for the primary outcome which was BPD.

Results:

The mean gestation age and birth weight of studied neonates were 28.3 ± 1.6 weeks and 1072 ± 180 g, respectively. BPD was occurred in 20 (31.3%) neonates in surfactant + budesonide group and 38 (59.4%) patients in surfactant group, P = 0.02. Respiratory support was needed in two groups similarly, but the mean duration of respiratory support was significantly longer in surfactant group in comparison with surfactant + budesonide group (mechanical ventilation 2.8 ± 0.6 vs. 0.8 ± 0.1 days, P = 0.006, nasal continuous positive airway pressure 5.2 ± 3.0 vs. 4.0 ± 3.5 days, P = 0.04 and high flow nasal cannula 7.7 ± 0.9 vs. 4.1 ± 0.5 days, P = 0.001).

Conclusion:

Based on our findings, the use of budesonide in addition to surfactant for rescue therapy of RDS significantly decreases the incidence of BPD and duration of respiratory support. Future studies are recommended with a large number of patients before routine administration of surfactant and budesonide combination.

Sample preparation strategy for the detection of steroid-like compounds using MALDI mass spectrometry imaging: pulmonary distribution of budesonide as a case study

Corticosteroids as budesonide can be effective in reducing topic inflammation processes in different organs. Therapeutic use of budesonide in respiratory diseases, like asthma, chronic obstructive pulmonary disease, and allergic rhinitis is well known. However, the pulmonary distribution of budesonide is not well understood, mainly due to the difficulties in tracing the molecule in lung samples without the addition of a label. In this paper, we present a matrix-assisted laser desorption/ionization mass spectrometry imaging protocol that can be used to visualize the pulmonary distribution of budesonide administered to a surfactant-depleted adult rabbit. Considering that budesonide is not easily ionized by MALDI, we developed an on-tissue derivatization method with Girard’s reagent P followed by ferulic acid deposition as MALDI matrix. Interestingly, this sample preparation protocol results as a very effective strategy to raise the sensitivity towards not only budesonide but also other corticosteroids, allowing us to track its distribution and quantify the drug inside lung samples.

Corticosteroids for the prevention of bronchopulmonary dysplasia in preterm infants: a network meta-analysis

OBJECTIVE

To determine the comparative efficacy and safety of corticosteroids in the prevention of bronchopulmonary dysplasia (BPD) in preterm infants.

STUDY DESIGN

We systematically searched PubMed, EMBASE and the Cochrane Library. Two reviewers independently selected randomised controlled trials (RCTs) of postnatal corticosteroids in preterm infants. A Bayesian network meta-analysis and subgroup analyses were performed.

RESULTS

We included 47 RCTs with 6747 participants. The use of dexamethasone at either high dose or low dose decreased the risk of BPD (OR 0.29, 95% credible interval (CrI) 0.14 to 0.52; OR 0.58, 95% CrI 0.39 to 0.76, respectively). High-dose dexamethasone was more effective than hydrocortisone, beclomethasone and low-dose dexamethasone. Early and long-term dexamethasone at either high dose or low dose decreased the risk of BPD (OR 0.11, 95% CrI 0.02 to 0.4; OR 0.37, 95% CrI 0.16 to 0.67, respectively). There were no statistically significant differences in the risk of cerebral palsy (CP) between different corticosteroids. However, high-dose and long-term dexamethasone ranked lower than placebo and other regimens in terms of CP. Subgroup analyses indicated budesonide was associated with a decreased risk of BPD in extremely preterm and extremely low birthweight infants (OR 0.60, 95% CrI 0.36 to 0.93).

CONCLUSIONS

Dexamethasone can reduce the risk of BPD in preterm infants. Of the different dexamethasone regimens, aggressive initiation seems beneficial, while a combination of high-dose and long-term use should be avoided because of the possible adverse neurodevelopmental outcome. Dexamethasone and inhaled corticosteroids need to be further evaluated in large-scale RCTs with long-term follow-ups.

Maternal omega-3 PUFA supplementation prevents hyperoxia-induced pulmonary hypertension in the offspring

Pulmonary hypertension (PH) and right ventricular hypertrophy (RVH) affect 16-25% of premature infants with bronchopulmonary dysplasia (BPD), contributing significantly to perinatal morbidity and mortality. Omega-3 polyunsaturated fatty acids (PUFA ω-3) can improve vascular remodeling, angiogenesis, and inflammation under pathophysiological conditions. However, the effects of PUFA ω-3 supplementation in BPD-associated PH are unknown. The present study aimed to evaluate the effects of PUFA ω-3 on pulmonary vascular remodeling, angiogenesis, and inflammatory response in a hyperoxia-induced rat model of PH. From embryonic day 15, pregnant Sprague-Dawley rats were supplemented daily with PUFA ω-3, PUFA ω-6, or normal saline (0.2 ml/day). After birth, pups were pooled, assigned as 12 per litter, randomly assigned to either air or continuous oxygen exposure (fraction of inspired oxygen = 85%) for 20 days, and then euthanized for pulmonary hemodynamic and morphometric analysis. We found that PUFA ω-3 supplementation improved survival, decreased right ventricular systolic pressure and RVH caused by hyperoxia, and significantly improved alveolarization, vascular remodeling, and vascular density. PUFA ω-3 supplementation produced a higher level of total ω-3 in lung tissue and breast milk and was found to reverse the reduced levels of VEGFA, VEGF receptor 2, angiopoietin-1 (ANGPT1), endothelial TEK tyrosine kinase, endothelial nitric oxide synthase, and nitric oxide concentrations in lung tissue and the increased ANGPT2 levels in hyperoxia-exposed rats. The beneficial effects of PUFA ω-3 in improving lung injuries were also associated with an inhibition of leukocyte infiltration and reduced expression of the proinflammatory cytokines IL-1β, IL-6, and TNF-α. These data indicate that maternal PUFA ω-3 supplementation strategies could effectively protect against infant PH induced by hyperoxia.

Use of Glucocorticoids for the Fetus and Preterm Infant

The soon-to-be-delivered fetus and preterm infant have been treated with glucocorticoids to prepare for postnatal life, historically for more than 40 years. The use of glucocorticoids is as much for replacement of cortisol in the setting of a poorly functioning hypothalamic-pituitary-adrenal axis in the preterm infant, as it is for prevention of long-term lung dysfunction. Potential negative effects of glucocorticoid treatment on brain development and function have been observed more often with dexamethasone therapy than with use of other glucocorticoids. Overall, glucocorticoid treatment has improved the outcome of the preterm infant.

Inhaled Drugs and Systemic Corticosteroids for Bronchopulmonary Dysplasia

All definitions of bronchopulmonary dysplasia (BPD) have limitations and a new definition for the purpose of clinical research, benchmarking, and prognostic prediction is needed. Different inhaled and systemic drugs are currently used to prevent or treat BPD. Despite some positive effects on BPD, more information about the effects of inhaled corticosteroids is required to assess overall efficacy and associated risks. One needs to balance the risks of neurodevelopmental impairment owing to systemic corticosteroids against those of BPD itself. Future studies should, therefore, focus on infants with a very high risk of developing BPD and include pharmacokinetics and long-term developmental outcomes.

Airway Remodeling and Hyperreactivity in a Model of Bronchopulmonary Dysplasia and Their Modulation by IL-1 Receptor Antagonist

Bronchopulmonary dysplasia (BPD) is a chronic disease of extreme prematurity that has serious long-term consequences including increased asthma risk. We earlier identified IL-1 receptor antagonist (IL-1Ra) as a potent inhibitor of murine BPD induced by combining perinatal inflammation (intraperitoneal LPS to pregnant dams) and exposure of pups to hyperoxia (fraction of inspired oxygen = 0.65). In this study, we determined whether airway remodeling and hyperresponsiveness similar to asthma are evident in this model, and whether IL-1Ra is protective. During 28-day exposure to air or hyperoxia, pups received vehicle or 10 mg/kg IL-1Ra by daily subcutaneous injection. Lungs were then prepared for histology and morphometry of alveoli and airways, or for real-time PCR, or inflated with agarose to prepare precision-cut lung slices to visualize ex vivo intrapulmonary airway contraction and relaxation by phase-contrast microscopy. In pups reared under normoxic conditions, IL-1Ra treatment did not affect alveolar or airway structure or airway responses. Pups reared in hyperoxia developed a severe BPD-like lung disease, with fewer, larger alveoli, increased subepithelial collagen, and increased expression of α-smooth muscle actin and cyclin D1. After hyperoxia, methacholine elicited contraction with similar potency but with an increased maximum reduction in lumen area (air, 44%; hyperoxia, 89%), whereas dilator responses to salbutamol were maintained. IL-1Ra treatment prevented hyperoxia-induced alveolar disruption and airway fibrosis but, surprisingly, not the increase in methacholine-induced airway contraction. The current study is the first to demonstrate ex vivo airway hyperreactivity caused by systemic maternal inflammation and postnatal hyperoxia, and it reveals further preclinical mechanistic insights into IL-1Ra as a treatment targeting key pathophysiological features of BPD.

Caffeine modulates glucocorticoid-induced expression of CTGF in lung epithelial cells and fibroblasts

Background

Although caffeine and glucocorticoids are frequently used to treat chronic lung disease in preterm neonates, potential interactions are largely unknown. While anti-inflammatory effects of glucocorticoids are well defined, their impact on airway remodeling is less characterized. Caffeine has been ascribed to positive effects on airway inflammation as well as remodeling. Connective tissue growth factor (CTGF, CCN2) plays a key role in airway remodeling and has been implicated in the pathogenesis of chronic lung diseases such as bronchopulmonary dysplasia (BPD) in preterm infants. The current study addressed the impact of glucocorticoids on the regulation of CTGF in the presence of caffeine using human lung epithelial and fibroblast cells.

Methods

The human airway epithelial cell line H441 and the fetal lung fibroblast strain IMR-90 were exposed to different glucocorticoids (dexamethasone, budesonide, betamethasone, prednisolone, hydrocortisone) and caffeine. mRNA and protein expression of CTGF, TGF-β1-3, and TNF-α were determined by means of quantitative real-time PCR and immunoblotting. H441 cells were additionally treated with cAMP, the adenylyl cyclase activator forskolin, and the selective phosphodiesterase (PDE)-4 inhibitor cilomilast to mimic caffeine-mediated PDE inhibition.

Results

Treatment with different glucocorticoids (1 μM) significantly increased CTGF mRNA levels in H441 (p < 0.0001) and IMR-90 cells (p < 0.01). Upon simultaneous exposure to caffeine (10 mM), both glucocorticoid-induced mRNA and protein expression were significantly reduced in IMR-90 cells (p < 0.0001). Of note, 24 h exposure to caffeine alone significantly suppressed basal expression of CTGF mRNA and protein in IMR-90 cells. Caffeine-induced reduction of CTGF mRNA expression seemed to be independent of cAMP levels, adenylyl cyclase activation, or PDE-4 inhibition. While dexamethasone or caffeine treatment did not affect TGF-β1 mRNA in H441 cells, increased expression of TGF-β2 and TGF-β3 mRNA was detected upon exposure to dexamethasone or dexamethasone and caffeine, respectively. Moreover, caffeine increased TNF-α mRNA in H441 cells (6.5 ± 2.2-fold, p < 0.05) which has been described as potent inhibitor of CTGF expression.

Conclusions

In addition to well-known anti-inflammatory features, glucocorticoids may have adverse effects on long-term remodeling by TGF-β1-independent induction of CTGF in lung cells. Simultaneous treatment with caffeine may attenuate glucocorticoid-induced expression of CTGF, thereby promoting restoration of lung homeostasis.

Prednisolone adsorption on lung surfactant models: insights on the formation of nanoaggregates, monolayer collapse and prednisolone spreading

The adsorption of prednisolone on a lung surfactant model was successfully performed using coarse grained molecular dynamics.

Update on Postnatal Steroids

Antenatal steroid treatment to enhance fetal lung maturity and surfactant treatment to prevent or treat respiratory distress syndrome have been major advances in perinatal medicine in the past 40 years contributing to improved outcomes for preterm infants. Use of postnatal steroids to prevent or treat chronic lung disease in preterm infants has been less successful and associated with adverse neurodevelopmental outcomes. Although early (in the first week of life) postnatal steroid treatment facilitates earlier extubation and reduces the risk of chronic lung disease, it is associated with adverse effects, such as hyperglycemia, hypertension, gastrointestinal bleeding and perforation, hypertrophic cardiomyopathy, growth failure, and cerebral palsy, and cannot be recommended. Early treatment with hydrocortisone may also improve survival without chronic lung disease, but concerns remain about possible adverse effects such as gastrointestinal perforation and sepsis, particularly in very preterm infants. Early inhaled budesonide also reduces the incidence of chronic lung disease but there are concerns that this may occur at the expense of increased risk of death. More studies of early low-dose steroids with adequate long-term follow-up are needed before they can be recommended for the prevention of chronic lung disease. Late (after the first week of life) postnatal steroids may have a better benefit-to-harm ratio than early steroids. A Cochrane Review shows that late steroid treatment reduces chronic lung disease, the combination of death and chronic lung disease at both 28 days and 36 weeks' corrected age, and the need for later rescue dexamethasone. Adverse effects include hyperglycemia, hypertension, hypertrophic cardiomyopathy, and severe retinopathy of prematurity but without an increase in blindness. Long-term neurodevelopmental effects are not significantly increased by late postnatal steroid treatment. Current recommendations are that postnatal steroid treatment should be reserved for preterm infants who are ventilator-dependent after the first 7-14 days of life and any course should be low dose and of short duration to facilitate endotracheal extubation. Budesonide/surfactant mixtures show some promise as a means of reducing chronic lung disease in preterm infants with severe respiratory distress syndrome, but further larger studies with long-term follow-up are needed before this treatment can be recommended as a routine intervention.

Abnormal findings in brainstem auditory evoked response at 36-37weeks of postconceptional age in babies with neonatal chronic lung disease

AIM

To examine brainstem auditory function at 36-37weeks of postconceptional age in preterm infants who are diagnosed to have neonatal chronic lung disease (CLD).

STUDY DESIGN

Preterm infants, born at 31 and less weeks of gestation, were studied at 36-37weeks of postconceptional age when they were diagnosed to have neonatal CLD. Brainstem auditory evoked response (BAER) was recorded and analyzed at different click rates.

RESULTS

Compared with healthy controls at the same postconceptional age, the CLD infants showed a slightly increase in BAER wave V latency. However, the I-V, and III-V interpeak intervals in the CLD infants were significantly increased. The III-V/I-III interval ratio was also significantly increased. The amplitudes of BAER waves III and V in the CLD infants tended to be reduced. These BAER findings were similar at all 21, 51 and 91/s clicks, although the abnormalities tended to be more significant at higher than at low click rates.

CONCLUSION

At 36-37weeks of postconceptional age, BAER was abnormal in preterm infants who were diagnosed to have neonatal CLD. This suggests that at time when the diagnosis of CLD is made there is functional impairment, reflecting poor myelination, in the brainstem auditory pathway in preterm infants with neonatal CLD.

Early inhaled steroid use in extremely low birthweight infants: a randomised controlled trial

OBJECTIVE

We hypothesised that a prophylactic inhaled steroid would prevent the progression of bronchopulmonary dysplasia (BPD) in extremely low birthweight infants (ELBWIs).

DESIGN

This study was a multicentre, randomised, double-blinded, placebo-controlled trial.

SETTING

This investigation was conducted in 12 level III neonatal intensive care units (NICUs).

PATIENTS

A total of 211 ELBWIs requiring ventilator support were enrolled.

INTERVENTION

Starting within 24 h of birth and continuing until 6 weeks of age or extubation, two doses of 50 μg fluticasone propionate (FP) or placebo were administered every 24 h.

MAIN OUTCOME MEASUREMENT

The primary outcome measure used to indicate the morbidity of severe BPD incidence was death or oxygen dependence at discharge from the NICU. The secondary measures were neurodevelopmental impairments (NDIs) at 18 months of postmenstrual age and 3 years of age. We performed subgroup analyses based on gestational week (GW) and the presence of chorioamnionitis (CAM).

RESULTS

Infants were randomised into the FP (n=107) or placebo (n=104) groups. No significant differences were detected between the FP and placebo groups with respect to either the frequency of death or the oxygen dependence at discharge or NDIs. In subgroup analyses, the frequencies of death and oxygen dependence at discharge were significantly decreased in the FP group for infants born at 24-26 GWs and for infants with CAM, regardless of the GW at birth.

CONCLUSIONS

Inhaled steroids have no effect on the prevention of severe BPD or long-term NDI but might decrease the severity of BPD for ELBWIs with a risk factor.

TRIAL REGISTRATION NUMBER

UMIN-CTR C000000405.

Systematic Review of Inhaled Bronchodilator and Corticosteroid Therapies in Infants with Bronchopulmonary Dysplasia: Implications and Future Directions

Background

There is much debate surrounding the use of inhaled bronchodilators and corticosteroids for infants with bronchopulmonary dysplasia (BPD).

Objective

The objective of this systematic review was to identify strengths and knowledge gaps in the literature regarding inhaled therapies in BPD and guide future research to improve long-termoutcomes.

Methods

The databases of Academic Search Complete, CINAHL, PUBMED/MEDLINE, and Scopus were searched for studies that evaluated both acute and long-term clinical outcomes related to the delivery and therapeutic efficacy of inhaled beta-agonists, anticholinergics and corticosteroids in infants with developing and/or established BPD.

Results

Of 181 articles, 22 met inclusion criteria for review. Five evaluated beta-agonist therapies (n = 84, weighted gestational age (GA) of 27.1(26–30) weeks, weighted birth weight (BW) of 974(843–1310) grams, weighted post menstrual age (PMA) of 34.8(28–39) weeks, and weighted age of 53(15–86) days old at the time of evaluation). Fourteen evaluated inhaled corticosteroids (n = 2383, GA 26.2(26–29) weeks, weighted BW of 853(760–1114) grams, weighted PMA of 27.0(26–31) weeks, and weighted age of 6(0–45) days old at time of evaluation). Three evaluated combination therapies (n = 198, weighted GA of 27.8(27–29) weeks, weighted BW of 1057(898–1247) grams, weighted PMA of 30.7(29–45) weeks, and age 20(10–111) days old at time of evaluation).

Conclusion

Whether inhaled bronchodilators and inhaled corticosteroids improve long-term outcomes in BPD remains unclear. Literature regarding these therapies mostly addresses evolving BPD. There appears to be heterogeneity in treatment responses, and may be related to varying modes of administration. Further research is needed to evaluate inhaled therapies in infants with severe BPD. Such investigations should focus on appropriate definitions of disease and subject selection, timing of therapies, and new drugs, devices and delivery methods as compared to traditional methods across all modalities of respiratory support, in addition to the assessment of long-term outcomes of initial responders.

Biomarkers for Bronchopulmonary Dysplasia in the Preterm Infant

Bronchopulmonary dysplasia (BPD) is a chronic inflammatory lung disease of very-low-birth-weight (VLBW) preterm infants, associated with arrested lung development and a need for supplemental oxygen. Over the past few decades, the incidence of BPD has significantly raised as a result of improved survival of VLBW infants requiring mechanical ventilation. While early disease detection is critical to prevent chronic lung remodeling and complications later in life, BPD is often difficult to diagnose and prevent due to the lack of good biomarkers for identification of infants at risk, and overlapping symptoms with other diseases, such as pulmonary hypertension (PH). Due to the current lack of effective treatment available for BPD and PH, research is currently focused on primary prevention strategies, and identification of biomarkers for early diagnosis, that could also represent potential therapeutic targets. In addition, novel histopathological, biochemical, and molecular factors have been identified in the lung tissue and in biological fluids of BPD and PH patients that could associate with the disease phenotype. In this review, we provide an overview of biomarkers for pediatric BPD and PH that have been identified in clinical studies using various biological fluids. We also present a brief summary of the information available on current strategies and guidelines to prevent and diagnose BPD and PH, as well as their pathophysiology, risk factors, and experimental therapies currently available.