Preventing bronchopulmonary dysplasia: new tools for an old challenge

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

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

Effects of bradycardia, hypoxemia and early intubation on bronchopulmonary dysplasia in very preterm infants: An observational study

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the most common pulmonary complication in preterm infants.

OBJECTIVES

The study aimed to explore the effects of bradycardia, hypoxemia, and early intubation on BPD in very preterm infants.

METHODS

This is a prospective observational cohort study. Preterm infants with a mean gestational age of 28.67 weeks were recruited from two level III neonatal intensive care units (NICUs) in Taiwan. Continuous electrocardiography was used to monitor heart rates and oxygen saturation (SpO2). Infants were monitored for heart rates of <100 beats per minute and SpO2 levels of <90 % lasting for 30 s. Generalized estimating equations were used to analyze the effects of bradycardia, hypoxemia, and early intubation on BPD in very preterm infants. Model fit was visually assessed using receiver operating characteristic curve analysis.

RESULTS

Bradycardia, hypoxemia, and early intubation significantly increased the odds of BPD among the preterm infants (N = 39) during NICU stay; the odds ratios for bradycardia, hypoxemia, and early intubation for BPD versus non-BPD were 1.058, 1.013, and 29.631, respectively (all p < 0.05). A model combining bradycardia, hypoxemia, and early intubation accurately predicted BPD development (area under the curve = 0.919).

CONCLUSIONS

Bradycardia, hypoxemia, and early intubation significantly increased the odds of BPD among very preterm infants during NICU stay. The model combining bradycardia, hypoxemia, and early intubation accurately predicted BPD development.

Lung ultrasound scores within the first 3 days of life to predict respiratory outcomes

BACKROUND

Lung ultrasound (LUS) is a rapid and simple method to evaluate preterm babies with respiratory distress. Lately, LUS has also been reported as an accurate predictor for bronchopulmonary dysplasia (BPD).

OBJECTIVES

The aim of the study was to investigate the relationship between the LUS scores within the first 3 days of life and respiratory outcomes including the need and the duration of invasive mechanical ventilation, and development of BPD.

METHODS

It was a retrospective observational study. Preterm infants younger than 32 weeks were included at an academic tertiary Neonatal Intensive Care Unit between 2018 and 2023. LUS was performed within the first 3 days. Each lung was divided into three regions and defined as a score of 0 to 3 points; the total score was obtained by adding the six regional scores. LUS scores were noted in two groups as the highest and lowest scores. Statistical analyses were done to predict respiratory outcomes.

RESULTS

Total 218 patients were enrolled; 40, 17, and 18 infants had mild, moderate, and severe BPD, respectively. BPD did not develop in 143 patients. Within the first 3 days, the highest and lowest LUS scores significantly predicted moderate-to-severe BPD (p < .001) (area under receiver operating characteristic [ROC] curve, 0.684-0.913; area under ROC curve 0.647-0.902; respectively). High LUS scores were also related with the need of mechanical ventilation (p < .001). There was not a significant correlation between the duration of mechanical ventilation and the LUS scores. Regression analysis revealed that the highest LUS scores within the first 3 days of life, sepsis, and the presence of hemodynamically significant patent ductus arteriosus (hsPDA) were significantly associated with the severity of BPD.

CONCLUSIONS

In preterm babies, the LUS scores were useful to predict BPD and the need of invasive ventilation in long term. However, it was not related with the length of invasive ventilation.

A clinical informatics approach to bronchopulmonary dysplasia: current barriers and future possibilities

Bronchopulmonary dysplasia (BPD) is a complex, multifactorial lung disease affecting preterm neonates that can result in long-term pulmonary and non-pulmonary complications. Current therapies mainly focus on symptom management after the development of BPD, indicating a need for innovative approaches to predict and identify neonates who would benefit most from targeted or earlier interventions. Clinical informatics, a subfield of biomedical informatics, is transforming healthcare by integrating computational methods with patient data to improve patient outcomes. The application of clinical informatics to develop and enhance clinical therapies for BPD presents opportunities by leveraging electronic health record data, applying machine learning algorithms, and implementing clinical decision support systems. This review highlights the current barriers and the future potential of clinical informatics in identifying clinically relevant BPD phenotypes and developing clinical decision support tools to improve the management of extremely preterm neonates developing or with established BPD. However, the full potential of clinical informatics in advancing our understanding of BPD with the goal of improving patient outcomes cannot be achieved unless we address current challenges such as data collection, storage, privacy, and inherent data bias.

Lung ultrasound score as a tool to predict severity of bronchopulmonary dysplasia in neonates born ≤25 weeks of gestational age

OBJECTIVE

The primary aim was to evaluate whether the addition of the posterior lung aided in diagnostic accuracy of predicting bronchopulmonary dysplasia (BPD) vs moderate-severe BPD (msBPD); the secondary aim was to explore the diagnostic accuracy of two protocols for BPD vs msBPD.

STUDY DESIGN

This was a single-center prospective observational study. Preterm infants with a gestational age ≤ 25 weeks were included. Two LUS score protocols were evaluated on the 14th day of life (DOL): (A) evaluating the anterolateral (LUS score-al) lung and (B) the anterolateral combined with posterior (LUS score-alp) lung. The LUS score range for the two protocols was 0-32 and 0-48, respectively.

RESULTS

A total of eighty-nine infants were enrolled. Both the LUS score-al and LUS score-alp were higher in neonates developing BPD and msBPD than in the rest of the cohort (LUS score-al 24 (23,26) vs 22 (20,23); LUS score-alp 36 (34,39) vs 28 (25,32)) (LUS score-al 25 (24,26) vs 23 (21,24); LUS score-alp 40 (39,40) vs 34 (28,36)). The LUS score-al on the 14th DOL showed a moderate diagnostic accuracy to predict BPD and msBPD (AUC 95% CI: 0.797 [0.697-0.896]; 0.811[0.713-0.909]), while the LUS score-alp significantly improved diagnostic accuracy of BPD and msBPD (AUC 95% CI: 0.902 [0.834-0.970]; 0.922 [0.848-0.996]). A cutoff of 25 points in the LUS score-al provided a sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of 76.9%, 79.4%, 3.7, and 0.3 respectively to predict msBPD. Meanwhile, that of 39 points in the LUS score-alp provided a sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of 81%, 98.4%, 50.5 and 0.19 to predict msBPD, respectively.

CONCLUSIONS

The LUS score on the 14th DOL can predict BPD and msBPD with moderate diagnostic accuracy. Apart from that, scanning posterior enhanced diagnostic accuracy.

Prematurity and BPD: what general pediatricians should know

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

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

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

A glucocorticoid-receptor agonist ameliorates bleomycin-induced alveolar simplification in newborn rats

BACKGROUND

Glucocorticoids (GCs) are highly effective yet problematic agents against bronchopulmonary dysplasia (BPD). The dimeric trans-activation of GCs induces unfavorable effects, while monomeric trans-repression suppresses inflammation-related genes. Recently, non-steroidal-selective glucocorticoid-receptor agonists and modulators (SEGRAMs) with only the trans-repressive action have been designed.

METHODS

Using a bleomycin (Bleo)-induced alveolar simplification newborn rat model (recapitulating arrested alveolarization during BPD), we evaluated the therapeutic effects of compound-A (CpdA), a SEGRAM. Sprague-Dawley rats were administered Bleo from postnatal day (PD) 0 to 10 and treated with dexamethasone (Dex) or CpdA from PD 0 to 13. The morphological changes and mRNA expression of inflammatory mediators, including interleukin (IL)-1β, C-X-C motif chemokine ligand 1 (CXCL1), and C-C motif chemokine 2 (CCL2) were investigated.

RESULTS

Similar to the effects of Dex, CpdA exerted protective effects on morphological derangements and inhibited macrophage infiltration and production of pro-inflammatory mediators in Bleo-treated animals. The effects of CpdA were probably mediated by GC receptor (GR)-dependent trans-repression, because unlike the Dex-treated group, anti-inflammatory genes specifically induced by GR-dependent trans-activation (such as "glucocorticoid-induced leucine zipper, GILZ") were not upregulated.

CONCLUSIONS

CpdA improved lung inflammation, inhibited the arrest of alveolar maturation, and restored histological and biochemical changes in a Bleo-induced alveolar simplification model.

IMPACT

SEGRAMs have attracted widespread attention because they are expected to not exhibit unfavorable effects of GCs. Compound A, one of the SEGRAMs, improved lung morphometric changes and decreased lung inflammation in a bleomycin-induced arrested alveolarization, a newborn rat model representing one of the main features of BPD pathology. Compound A did not elicit bleomycin-induced poor weight gain, in contrast to dexamethasone treatment. SEGRAMs, including compound A, may be promising candidates for the therapy of BPD with less adverse effects compared with GCs.

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.

Lung Ultrasound for Predicting the Respiratory Outcome in Patients with Bronchopulmonary Dysplasia

OBJECTIVE

This study aimed to investigate the utility of lung ultrasound (LUS) with whole chest scanning for predicting respiratory outcomes in patients with bronchopulmonary dysplasia (BPD).

STUDY DESIGN

We performed a prospective observational study. Preterm infants of less than 32 weeks' gestational age requiring oxygen therapy at 28 days of life were included. LUS was performed on day 28, at 36 weeks' postmenstrual age, and at the time of discharge. Each lung was divided into three regions by the anterior and posterior axillary lines and received an LUS score of 0 to 3 points; the total score was obtained by adding the six regional scores. The classification of BPD was determined based on the National Institute of Child and Human Development. The outcomes of this study were the development of moderate-to-severe BPD and the need for home oxygen therapy (HOT).

RESULTS

We enrolled 87 patients; 39, 33, and 15 infants had mild, moderate, and severe BPD, respectively. The LUS score correlated with BPD severity and exhibited an improvement trend with time toward the point of discharge. LUS at 28 days of life predicted moderate-to-severe BPD with an area under the curve of 0.95 (95% confidence interval: 0.91-0.99) and HOT with an area under the curve of 0.95 (95% confidence interval: 0.81-1.0).

CONCLUSION

LUS with whole chest scanning is useful for predicting respiratory outcomes in patients with BPD, as well as for understanding BPD severity or clinical improvement trends.

KEY POINTS

· LUS predicts respiratory outcomes in patients with BPD.. · LUS indicates BPD severity.. · LUS can show clinical improvement with time..

The benefits, limitations and opportunities of preclinical models for neonatal drug development

Increased research to improve preclinical models to inform the development of therapeutics for neonatal diseases is an area of great need. This article reviews five common neonatal diseases – bronchopulmonary dysplasia, retinopathy of prematurity, necrotizing enterocolitis, perinatal hypoxic–ischemic encephalopathy and neonatal sepsis – and the available in vivo, in vitro and in silico preclinical models for studying these diseases. Better understanding of the strengths and weaknesses of specialized neonatal disease models will help to improve their utility, may add to the understanding of the mode of action and efficacy of a therapeutic, and/or may improve the understanding of the disease pathology to aid in identification of new therapeutic targets. Although the diseases covered in this article are diverse and require specific approaches, several high-level, overarching key lessons can be learned by evaluating the strengths, weaknesses and gaps in the available models. This Review is intended to help guide current and future researchers toward successful development of therapeutics in these areas of high unmet medical need.

Summary: This article reviews and analyzes the available preclinical models for five common neonatal diseases to direct therapeutic development in these areas of high unmet medical need.

Maladaptive functional changes in alveolar fibroblasts due to perinatal hyperoxia impair epithelial differentiation

Infants born prematurely worldwide have up to a 50% chance of developing bronchopulmonary dysplasia (BPD), a clinical morbidity characterized by dysregulated lung alveolarization and microvascular development. It is known that PDGFR alpha-positive (PDGFRA+) fibroblasts are critical for alveolarization and that PDGFRA+ fibroblasts are reduced in BPD. A better understanding of fibroblast heterogeneity and functional activation status during pathogenesis is required to develop mesenchymal population-targeted therapies for BPD. In this study, we utilized a neonatal hyperoxia mouse model (90% O2 postnatal days 0-7, PN0-PN7) and performed studies on sorted PDGFRA+ cells during injury and room air recovery. After hyperoxia injury, PDGFRA+ matrix and myofibroblasts decreased and PDGFRA+ lipofibroblasts increased by transcriptional signature and population size. PDGFRA+ matrix and myofibroblasts recovered during repair (PN10). After 7 days of in vivo hyperoxia, PDGFRA+ sorted fibroblasts had reduced contractility in vitro, reflecting loss of myofibroblast commitment. Organoids made with PN7 PDGFRA+ fibroblasts from hyperoxia in mice exhibited reduced alveolar type 1 cell differentiation, suggesting reduced alveolar niche-supporting PDGFRA+ matrix fibroblast function. Pathway analysis predicted reduced WNT signaling in hyperoxia fibroblasts. In alveolar organoids from hyperoxia-exposed fibroblasts, WNT activation by CHIR increased the size and number of alveolar organoids and enhanced alveolar type 2 cell differentiation.

Pulmonary artery dopplers for early prediction of risk for bronchopulmonary dysplasia in extremely low birth weight babies

OBJECTIVE

The early abnormal pulmonary vasoreactivity observed in babies at risk of Bronchopulmonary dysplasia (BPD) increases the pulmonary vascular resistance. This can be assessed non-invasively using Time to Peak Velocity:Right Ventricular Ejection Time ratio (TPV:RVET) measured from pulmonary artery Doppler waveform obtained using echocardiogram. We postulate that screening for this early can predict BPD in this cohort. The objective of the study was to determine the utility of TPV:RVET in early prediction of BPD in Extremely Low Birth Weight (ELBW) babies born less than 1250grams Birth Weight.

METHODS

This was a single-center retrospective cohort study of ELBW babies born<29 weeks over 4 year period who had echocardiogram between 7-21 days of life. TPV:RVET ratio was measured from pulmonary artery Doppler waveform obtained using echocardiogram. The main outcome was BPD at 36 weeks corrected gestation. The predictive ability of TPV:RVET (cut off 0.34) for subsequent development of BPD was analyzed using ROC.

RESULTS

Of 589 ELBW<29 weeks, 207 babies were eligible. BPD was found in 60.4%. The TPV:RVET at 0.34 had sensitivity 76.8% (95%CI 68.4-83.9), specificity 85.4% (95%CI 75.8-92.2), positive predictive value 88.9% (95%CI 81.4-94.1), negative predictive value 70.7% (95%CI 60.7-79), and ROC area 0.811 (95%CI 0.757-0.864). Odds ratio of having BPD for TPV:RVET at 0.34 was 19.9 (95%CI 8.19-48.34) and increased by 1.07 (95%CI 1.05-1.09) with every additional days of mechanical ventilation. TPV:RVET ratio had 92.75% inter-observer agreement with kappa 0.83.

CONCLUSION

TPV:RVET ratio is a good and reliable early screening tool for subsequent development of BPD in ELBW babies with substantial inter-observer agreement.

The protective effects of apocynin in hyperoxic lung injury in neonatal rats

AIM

Inflammation and oxidate stress are significant factors in the pathogenesis of bronchopulmonary dysplasia (BPD). The aim of this study is to investigate the efficacy of apocynin (APO), an anti-inflammatory, antioxidant, and antiapoptotic drug, in the prophylaxis of neonatal hyperoxic lung injury.

METHOD

This experimental study included 40 neonatal rats divided into the control, APO, BPD, and BPD + APO groups. The control and APO groups were kept in a normal room environment, while the BPD and BPD + APO groups were kept in a hyperoxic environment. The rats in the APO and BPD + APO groups were administered intraperitoneal APO, while the control and BPD rats were administered ordinary saline. At the end of the trial, lung tissue was evaluated with respect to the degree of histopathological injury, apoptosis, oxidant and antioxidant capacity, and severity of inflammation.

RESULT

The BPD and BPD + APO groups exhibited higher mean histopathological injury and alveolar macrophage scores compared to the control and APO groups. Both scores were lower in the BPD + APO group in comparison to the BPD group. The BPD + APO group had a significantly lower average of TUNEL positive cells than the BPD group. The lung tissue examination indicated significantly higher levels of mean malondialdehyde (MDA), total oxidant status (TOS), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) in the BPD group compared to the control and APO groups. While the TNF-α and IL-1β levels of the BPD + APO group were similar to that of the control group, the MDA and TOS levels were higher compared to the controls and lower compared to the BPD group. The BPD group demonstrated significantly lower levels/activities of mean total antioxidant status, glutathione reductase, superoxide dismutase, glutathione peroxidase in comparison to the control and APO groups. While the mean antioxidant enzyme activity of the BPD + APO group was lower than the control group, it was significantly higher compared to the BPD group.

CONCLUSION

This is the first study in the literature to reveal through an experimental neonatal hyperoxic lung injury that APO, an anti-inflammatory, antioxidant, and antiapoptotic drug, exhibits protective properties against the development of BPD.

The Value of Lung Ultrasound Score in Neonatology

Point-of-care lung ultrasound (LUS) is increasingly applied in the neonatal intensive care unit (NICU). Diagnostic applications for LUS in the NICU contain the diagnosis of many common neonatal pulmonary diseases (such as Respiratory distress syndrome, Transient tachypnea of the newborn, Meconium aspiration syndrome, Pneumonia, Pneumothorax, and Pleural effusion) which have been validated. In addition to being employed as a diagnostic tool in the classical sense of the term, recent studies have shown that the number and type of artifacts are associated with lung aeration. Based on this theory, over the last few years, LUS has also been used as a semi-quantitative method or as a "functional" tool. Scores have been proposed to monitor the progress of neonatal lung diseases and to decide whether or not to perform a specific treatment. The semi-quantitative LUS scores (LUSs) have been developed to predict the demand for surfactant therapy, the need of respiratory support and the progress of bronchopulmonary dysplasia. Given their ease of use, accuracy and lack of invasiveness, the use of LUSs is increasing in clinical practice. Therefore, this manuscript will review the application of LUSs in neonatal lung diseases.

Extracellular Vesicles Protect the Neonatal Lung from Hyperoxic Injury through the Epigenetic and Transcriptomic Reprogramming of Myeloid Cells

Rationale: Mesenchymal stem/stromal cell (MSC)-small extracellular vesicle (MEx) treatment has shown promise in experimental models of neonatal lung injury. The molecular mechanisms by which MEx afford beneficial effects remain incompletely understood. Objectives: To investigate the therapeutic mechanism of action through assessment of MEx biodistribution and impact on immune cell phenotypic heterogeneity. Methods: MEx were isolated from the conditioned medium of human umbilical cord Wharton's jelly-derived MSCs. Newborn mice were exposed to hyperoxia (HYRX, 75% O2) from birth and returned to room air at Postnatal Day 14 (PN14). Mice received either a bolus intravenous MEx dose at PN4 or bone marrow-derived myeloid cells (BMDMy) pretreated with MEx. Animals were killed at PN4, PN7, PN14, or PN28 to characterize MEx biodistribution or for assessment of pulmonary parameters. The therapeutic role of MEx-educated BMDMy was determined in vitro and in vivo. Measurements and Main Results: MEx therapy ameliorated core histological features of HYRX-induced neonatal lung injury. Biodistribution and mass cytometry studies demonstrated that MEx localize in the lung and interact with myeloid cells. MEx restored the apportion of alveolar macrophages in the HYRX-injured lung and concomitantly suppressed inflammatory cytokine production. In vitro and ex vivo studies revealed that MEx promoted an immunosuppressive BMDMy phenotype. Functional assays demonstrated that the immunosuppressive actions of BMDMy are driven by phenotypically and epigenetically reprogrammed monocytes. Adoptive transfer of MEx-educated BMDMy, but not naive BMDMy, restored alveolar architecture, blunted fibrosis and pulmonary vascular remodeling, and improved exercise capacity. Conclusions: MEx ameliorate hyperoxia-induced neonatal lung injury though epigenetic and phenotypic reprogramming of myeloid cells.

Does Chrysin prevent severe lung damage in Hyperoxia-Induced lung injury Model?

BACKGROUND

Oxidative stress and inflammation play a critical role in the etiopathogenesis of bronchopulmonary dysplasia (BPD). The aim of this study was to evaluate the preventive effect of Chrysin (CH), an antioxidant, antiinflammatory, antiapoptotic and antifibrotic drug, on hyperoxia-induced lung injury in a neonatal rat model.

METHODS

Forty infant rats were divided into four groups labeled the Control, CH, BPD, and BPD + CH. The control and CH groups were kept in a normal room environment, while the BPD and BPD + CH groups were kept in a hyperoxic (90-95%) environment. At the end of the study, lung tissue was evaluated with respect to apoptosis, histopathological damage and alveolar macrophage score as well as oxidant capacity, antioxidant capacity, and inflammation.

RESULTS

Compared to the BPD + CH and control groups, the lung tissues of the BPD group displayed substantially higher levels of MDA, TOS, TNF-α, and IL-1β (p < 0.05). While the BPD + CH group showed similar levels of TNF-α and IL-1β as the control group, MDA and TOS levels were higher than the control group, and significantly lower than the BPD group (p < 0.05). The BPD group exhibited considerably lower levels of TAS, SOD, GSH, and GSH-Px in comparison to the control group (p < 0.05). The BPD and BPD + CH groups exhibited higher mean scores of histopathological damage and alveolar macrophage when compared to the control and CH groups (p ≤ 0.0001). Both scores were found to be lower in the BPD + CH group in comparison to the BPD group (p ≤ 0.0001). The BPD + CH group demonstrated a significantly lower average of TUNEL and caspase-3 positive cells than the BPD group.

CONCLUSION

We found that prophylaxis with CH results in lower histopathological damage score and reduces apoptotic cell count, inflammation and oxidative stress while increasing anti-oxidant capacity.

Bronchopulmonary dysplasia precursors influence risk of white matter injury and adverse neurodevelopmental outcome in preterm infants

BACKGROUND

Cumulative supplemental oxygen (CSO) and cumulative mean airway pressure (CMAP) are associated with bronchopulmonary dysplasia (BPD) in preterm infants, but their relationships to white matter injury (WMI) and neurodevelopment have not been evaluated.

METHODS

Preterm infants <32 weeks' gestation were prospectively imaged with 3 T MRI near term. CSO and CMAP were retrospectively summed over the first 14 and 28 days. Neurodevelopment was assessed at 30 months adjusted using the Bayley-III. ROC and linear regression were used to evaluate the relationship between CSO, CMAP, and BPD with WMI and neurodevelopmental performance, respectively.

RESULTS

Of the 87 infants, 30 (34.5%) had moderate-severe BPD, which was associated with WMI (OR 5.5, 95% CI 1.1-34.9, p = 0.012). CSO and CMAP predicted WMI as well as BPD (AUC 0.68-0.77). CSO was independently associated with decreased language and cognitive performance (mean difference at 14 days: -11.0, 95% CI -19.8 to -2.2, p = 0.015 and -9.8, 95% CI -18.9 to -0.7, p = 0.035, respectively) at 30 months adjusted.

CONCLUSIONS

BPD precursors predict WMI as well as BPD. Cumulative supplemental oxygen over the first 14 days of life is independently associated with lower language and cognitive performances. These data suggest that early respiratory status influences the risk of adverse neurodevelopment in preterm infants.

IMPACT

Respiratory precursors to bronchopulmonary dysplasia (BPD), cumulative supplemental oxygen and mean airway pressure, over the first 14-28 days performed as well as BPD for the prediction of white matter injury on MRI in preterm infants. Cumulative supplemental oxygen was independently associated with lower language and cognitive performance on the Bayley-III at 30 months adjusted. These data suggest that early respiratory status may help explain why BPD is independently associated with adverse neurodevelopmental outcomes in the preterm population and highlights the importance of interventions targeting respiratory status as a potential avenue to improve neurodevelopmental outcomes.

The Role of Nutrition in the Prevention and Management of Bronchopulmonary Dysplasia: A Literature Review and Clinical Approach

Bronchopulmonary dysplasia (BPD) remains the most common severe complication of preterm birth, and nutrition plays a crucial role in lung growth and repair. A practical nutritional approach for infants at risk of BPD or with established BPD is provided based on a comprehensive literature review. Ideally, infants with BPD should receive a fluid intake of not more than 135-150 mL/kg/day and an energy intake of 120-150 kcal/kg/day. Providing high energy in low volume remains a challenge and is the main cause of growth restriction in these infants. They need a nutritional strategy that encompasses early aggressive parenteral nutrition and the initiation of concentrated feedings of energy and nutrients. The order of priority is fortified mother's own milk, followed by fortified donor milk and preterm enriched formulas. Functional nutrient supplements with a potential protective role against BPD are revisited, despite the limited evidence of their efficacy. Specialized nutritional strategies may be necessary to overcome difficulties common in BPD infants, such as gastroesophageal reflux and poorly coordinated feeding. Planning nutrition support after discharge requires a multidisciplinary approach to deal with multiple potential problems. Regular monitoring based on anthropometry and biochemical markers is needed to guide the nutritional intervention.

Neonatal lymphocyte subpopulations analysis and maternal preterm premature rupture of membranes: a pilot study

OBJECTIVES

Preterm premature rupture of membranes (pPROM) causes preterm delivery, and increases maternal T-cell response against the fetus. Fetal inflammatory response prompts maturation of the newborn's immunocompetent cells, and could be associated with unfavorable neonatal outcome. The aims were (1) to examine the effects of pPROM on the newborn's and mother's immune system and (2) to assess the predictive value of immune system changes in neonatal morbidity.

METHODS

Mother-newborn pairs (18 mothers and 23 newborns) who experienced pPROM and controls (11 mothers and 14 newborns), were enrolled. Maternal and neonatal whole blood samples underwent flow cytometry to measure lymphocyte subpopulations.

RESULTS

pPROM-newborns had fewer naïve CD4 T-cells, and more memory CD4 T-cells than control newborns. The effect was the same for increasing pPROM latency times before delivery. Gestational age and birth weight influenced maturation of the newborns' lymphocyte subpopulations and white blood cells, notably cytotoxic T-cells, regulatory T-cells, T-helper cells (absolute count), and CD4/CD8 ratio. Among morbidities, fewer naïve CD8 T-cells were found in bronchopulmonary dysplasia (BPD) (p=0.0009), and more T-helper cells in early onset sepsis (p=0.04).

CONCLUSIONS

pPROM prompts maturation of the newborn's T-cell immune system secondary to antigenic stimulation, which correlates with pPROM latency. Maternal immunity to inflammatory conditions is associated with a decrease in non-major histocompatibility complex (MHC)-restricted cytotoxic cells.

Prematurity alters the progenitor cell program of the upper respiratory tract of neonates

The impact of prematurity on human development and neonatal diseases, such as bronchopulmonary dysplasia, has been widely reported. However, little is known about the effects of prematurity on the programs of stem cell self-renewal and differentiation of the upper respiratory epithelium, which is key for adaptation to neonatal life. We developed a minimally invasive methodology for isolation of neonatal basal cells from nasopharyngeal (NP) aspirates and performed functional analysis in organotypic cultures to address this issue. We show that preterm NP progenitors have a markedly distinct molecular signature of abnormal proliferation and mitochondria quality control compared to term progenitors. Preterm progenitors had lower oxygen consumption at baseline and were unable to ramp up consumption to the levels of term cells when challenged. Although they formed a mucociliary epithelium, ciliary function tended to decline in premature cells as they differentiated, compared to term cells. Together, these differences suggested increased sensitivity of preterm progenitors to environmental stressors under non-homeostatic conditions.

The Predictive Value of Lung Ultrasound Scores in Developing Bronchopulmonary Dysplasia: A Prospective Multicenter Diagnostic Accuracy Study

BACKGROUND

Different lung ultrasound (LUS) scanning protocols have been used, and the results in terms of diagnostic accuracy are heterogeneous.

RESEARCH QUESTIONS

What is the diagnostic accuracy of the LUS score to predict moderate to severe bronchopulmonary dysplasia (msBPD)? Does scanning of posterior lung fields improve the diagnostic accuracy?

STUDY DESIGN AND METHODS

This was a multicenter prospective, observational study in six centers. Two LUS aeration scores, one involving only anterolateral lung fields and the other adding the posterior fields were obtained at birth, on the third day of life (DOL), on the seventh DOL, on the 14th DOL, and on the 21st DOL. The diagnostic accuracy of both scores to predict msBPD was assessed at each time point.

RESULTS

Eight hundred thirty-two LUS examinations in 298 infants were included. Both LUS score using anterolateral and posterior fields and LUS score using only anterolateral fields showed a similar moderate diagnostic accuracy to predict msBPD on the third DOL (area under the receiver operating characteristic curve [AUC] 95% CI, 0.68-0.85 vs 0.68-0.85; P = .97), seventh DOL (AUC 95% CI, 0.74-0.85 vs 0.74-0.84; P = .26), and 21st DOL (AUC 95% CI, 0.72-0.86 vs 0.74-0.88; P = .17). The LUS score using anterolateral and posterior fields was slightly more accurate at 14th DOL (AUC 95% CI, 0.69-0.83 vs 0.66-0.80; P = .01). A cutoff of 8 points in the LUS score using only anterolateral fields on the seventh DOL provided a sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of 70%, 79%, 3.3, and 0.38, respectively, to predict msBPD. Adding gestational age (GA) and sex improved the discriminative value without significant differences compared with a predictive model based on multiple clinical variables: AUC 95% CI, 0.77-0.88 vs 0.80-0.91 (P = .52).

INTERPRETATION

The LUS score is able to predict msBPD from the third DOL with a moderate diagnostic accuracy. Scanning posterior lung fields slightly improved diagnostic accuracy only at the 14th DOL. Adding GA and sex improves the diagnostic accuracy of the LUS scores. The LUS score is useful to stratify BPD risk early after birth.

Development and Validation of a Nomogram for Predicting Bronchopulmonary Dysplasia in Very-Low-Birth-Weight Infants

Background: Bronchopulmonary dysplasia is a common pulmonary disease in newborns and is one of the main causes of death. The aim of this study was to build a new simple-to-use nomogram to screen high-risk populations. Methods: In this single-center retrospective study performed from January 2017 to December 2020, we reviewed data on very-low-birth-weight infants whose gestational ages were below 32 weeks. LASSO regression was used to select variables for the risk model. Then, we used multivariable logistic regression to build the prediction model incorporating these selected features. Discrimination was assessed by the C-index, and and calibration of the model was assessed by and calibration curve and the Hosmer-Lemeshow test. Results: The LASSO regression identified gestational age, duration of ventilation and serum NT-proBNP in the 1st week as significant predictors of BPD. The nomogram-illustrated model showed good discrimination and calibration. The C-index was 0.853 (95% CI: 0.851-0.854) in the training set and 0.855 (95% CI: 0.77-0.94) in the validation set. The calibration curve and Hosmer-Lemeshow test results showed good calibration between the predictions of the nomogram and the actual observations. Conclusion: We demonstrated a simple-to-use nomogram for predicting BPD in the early stage. It may help clinicians recognize high-risk populations.

Early assessment of lung aeration using an ultrasound score as a biomarker of developing bronchopulmonary dysplasia: a prospective observational study

The objective of this study was to assess the predictive value of a lung ultrasound (LUS) score in the development of moderate-severe bronchopulmonary dysplasia (sBPD). This was a prospective  observational diagnostic accuracy study in a third-level neonatal intensive care unit. Preterm infants with a gestational age below 32 weeks were included. A LUS score (range 0-24 points) was calculated by assessing aeration semiquantitatively (0-3 points) in eight lung zones on the 7th day of life (DOL) and repeated on the 28th DOL. ROC curves and logistic regression were used for analysis. Forty-two preterm infants were included. The LUS on the 7th DOL had an area under the receiver operating characteristic curve (AUROC) of 0.94 (95% CI: 0.87-1) for the prediction of sBPD (optimal cutoff of ≥8 points: sensitivity 93%, specificity 91%). The LUS score was independently associated with sBPD [OR 2.1 (95% CI: 1.1-3.9), p = 0.022, for each additional point in the score]. Conclusions: Lung aeration as assessed by LUS on the 7th DOL may predict the development of sBPD.

Phenotypes of Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is the most common chronic morbidity in preterm infants. In the absence of effective interventions, BPD is currently a major therapeutic challenge. Several risk factors are known for this multifactorial disease that results in disrupted lung development. Inflammation plays an important role and leads to persistent airway and pulmonary vascular disease. Since corticosteroids are potent anti-inflammatory agents, postnatal corticosteroids have been used widely for BPD prevention and treatment. However, the clinical responses vary to a great degree across individuals, and steroid-related complications remain major concerns. Emerging studies on the molecular mechanism of lung alveolarization during inflammatory stress will elucidate the complicated pathway and help discover novel therapeutic targets. Moreover, with the advances in metabolomics, there are new opportunities to identify biomarkers for early diagnosis and prognosis prediction of BPD. Pharmacometabolomics is another novel field aiming to identify the metabolomic changes before and after a specific drug treatment. Through this "metabolic signature," a more precise treatment may be developed, thereby avoiding unnecessary drug exposure in non-responders. In the future, more clinical, genetic, and translational studies would be required to improve the classification of BPD phenotypes and achieve individualized care to enhance the respiratory outcomes in preterm infants.

Mesenchymal stromal cell-derived small extracellular vesicles restore lung architecture and improve exercise capacity in a model of neonatal hyperoxia-induced lung injury

Early administration of mesenchymal stromal cell (MSC)-derived small extracellular vesicles (MEx) has shown considerable promise in experimental models of bronchopulmonary dysplasia (BPD). However, the ability of MEx to reverse the long-term pulmonary complications associated with established BPD remains unknown. In this study, MEx were isolated from media conditioned by human Wharton’s Jelly-derived MSC cultures. Newborn mice (FVB strain) were exposed to hyperoxia (HYRX (75% O2)) before returning to room air at postnatal day 14 (PN14). Following prolonged HYRX-exposure, animals received a single MEx dose at PN18 or serial MEx treatments at PN18-39 (“late” intervention). This group was compared to animals that received an early single MEx dose at PN4 (“early” intervention). Animals were harvested at PN28 or 60 for assessment of pulmonary parameters. We found that early and late MEx interventions effectively ameliorated core features of HYRX-induced neonatal lung injury, improving alveolar simplification, pulmonary fibrosis, vascular remodelling and blood vessel loss. Exercise capacity testing and assessment of pulmonary hypertension (PH) showed functional improvements following both early and late MEx interventions. In conclusion, delivery of MEx following prolonged HYRX-exposure improves core features of experimental BPD, restoring lung architecture, decreasing pulmonary fibrosis and vascular muscularization, ameliorating PH and improving exercise capacity. Taken together, delivery of MEx may not only be effective in the immediate neonatal period to prevent the development of BPD but may provide beneficial effects for the management and potentially the reversal of cardiorespiratory complications in infants and children with established BPD.

[Safety and efficacy of caffeine use started at different time in preterm infants: a multicenter study in Jiangsu Province, China]

OBJECTIVE

To study the efficacy and safety of caffeine used in the early (≤72 hours after birth) and late (>72 hours after birth) stage in preterm infants with a gestational age of ≤31 weeks.

METHODS

A retrospective analysis was performed for 640 preterm infants (with a gestational age of ≤31 weeks) who were admitted to the neonatal intensive care unit of eight hospitals in Jiangsu Province, China. Of the 640 preterm infants, 510 were given caffeine in the early stage (≤72 hours after birth; early use group) and 130 were given caffeine in the late stage (>72 hours after birth; late use group). The clinical data were compared between the two groups.

RESULTS

There were no significant differences in birth weight, Apgar score, sex, gestational age, and age on admission between the two groups (P>0.05). Compared with the late use group, the early use group had a significantly younger age at the beginning and withdrawal of caffeine treatment (P<0.05) and a significantly shorter duration of caffeine treatment (P<0.05). There was no significant difference in respiratory support on admission between the two groups (P>0.05). Compared with the late use group, the early use group had significantly lower incidence rate of apnea (P<0.05) and significantly shorter oxygen supply time and length of hospital stay (P<0.05). There were no significant differences between the two groups in the incidence rates of neonatal intracranial hemorrhage, periventricular leukomalacia, necrotizing enterocolitis, retinopathy of prematurity, and patent ductus arteriosus at discharge and NBNA score at the corrected gestational age of 40 weeks (P>0.05). However, significant differences were found in the incidence of bronchopulmonary dysplasia and the rate of home oxygen therapy, but there was no significant difference in the mortality rate between the two groups (P>0.05).

CONCLUSIONS

Early use of caffeine can shorten the duration of caffeine treatment, oxygen supply time, and length of hospital stay, with little adverse effect, in preterm infants with a gestational age of ≤31 weeks.

Stem cell therapy for preventing neonatal diseases in the 21st century: Current understanding and challenges

Diseases of the preterm newborn such as bronchopulmonary dysplasia, necrotizing enterocolitis, cerebral palsy, and hypoxic-ischemic encephalopathy continue to be major causes of infant mortality and long-term morbidity. Effective therapies for the prevention or treatment for these conditions are still lacking as recent clinical trials have shown modest or no benefit. Stem cell therapy is rapidly emerging as a novel therapeutic tool for several neonatal diseases with encouraging pre-clinical results that hold promise for clinical translation. However, there are a number of unanswered questions and facets to the development of stem cell therapy as a clinical intervention. There is much work to be done to fully elucidate the mechanisms by which stem cell therapy is effective (e.g., anti-inflammatory versus pro-angiogenic), identifying important paracrine mediators, and determining the timing and type of therapy (e.g., cellular versus secretomes), as well as patient characteristics that are ideal. Importantly, the interaction between stem cell therapy and current, standard-of-care interventions is nearly completely unknown. In this review, we will focus predominantly on the use of mesenchymal stromal cells for neonatal diseases, highlighting the promises and challenges in clinical translation towards preventing neonatal diseases in the 21st century.

Prediction of Bronchopulmonary Dysplasia in Preterm Infants Using Postnatal Risk Factors

Objective: To identify postnatal risk factors for bronchopulmonary dysplasia (BPD) development in preterm infants with gestational age ≤32 weeks. Methods: Seventy-two preterm infants(30 with BPD and 42 non-BPD controls) admitted in the neonatal intensive care unit (NICU) of the Children's Hospital of Soochow University during 2017 were enrolled in this prospective longitudinal study. Perinatal clinical data, a neonatal critical illness score (NCIS), different soluble B7-H3(sB7-H3), and interleukin-18 (IL-18) levels by days after birth were collected. An early predictive model for BPD development was established based on clinical data using multiple logistic regression analysis. And the sensitivity and specificity of the model were assesed by ROC curve. Results: Electrolyte disturbances, hemodynamically significant patent ductus arteriosus (hs-PDA), and the age that infants achieved 120 kcal/kg.d via enteral feeding ≥40 days after birth were found to be associated with the BPD pathogenesis. Serum sB7-H3, IL-18, and NCIS were significantly higher in the BPD group compared to the non-BPD group (p < 0.05). BPD group had significantly lower enteral fluid and caloric intake compared to the non-BPD group at 1, 7, 14, and 28 days after birth. The risk factors were analyzed by multiple logistic regression and a predictive model of a combination of sB7-H3 (day 7), IL-18 (day 14), NCIS, and clinical risk factors was evaluated via ROC curve with an area under the curve (AUC) of 0.960 having sensitivity of 86.7% and a specificity of 97.6%, respectively. Conclusion: The causes of BPD are multifactorial postnatal risk factors. And the combination of sB7-H3 (day 7), IL-18 (day 14), NCIS, and clinical risk factors (electrolyte disturbances, hs-PDA, and the age that infants achieved 120 kcal/kg.d via enteral feeding ≥40 days after birth) might be served as an optimal predictive model for the occurrence of BPD.

Predicting the likelihood of bronchopulmonary dysplasia in premature neonates

Introduction: Bronchopulmonary dysplasia (BPD) is the most common serious pulmonary morbidity in premature infants. Despite ongoing advances in neonatal care, the incidence of BPD has not improved. A potential explanation for this phenomenon is the limited ability for accurate early prediction of the risk of BPD. BPD continues to represent a therapeutic challenge and no single effective therapy exists for this condition. Areas covered: Here, we review risk factors of BPD derived from clinical data, biological fluid biomarkers, respiratory management data, and scientific advancements using 'omics' technologies, and their ability to predict the pathogenesis of BPD in preterm neonates. Risk factors and biomarkers were identified via literature search with a focus on the last 5 years of data. Expert opinion: The most accurate predictive tools utilize risk factors that encompass a variety of categories. Numerous predictive models have been proposed but suffer from a lack of adequate validation. An ideal model should include multiple, easily measurable variables validated across a heterogeneous population. In addition to evaluating recent BPD prediction models, we suggest approaches to enhance future models.

Bronchopulmonary dysplasia: how can we improve its outcomes?

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of preterm infants with multiple factors affected from prenatal to postnatal periods. Despite significant advances in neonatal care over almost 50 years, BPD rates have not decreased; in fact, they may have even increased. Since more preterm infants, even at periviable gestational age, survive today, different stages of lung development affect the pathogenesis of BPD. Hence, the definition of BPD has changed from “old” to “new.” In this review, we discuss the various definitions of BPD, risk factors from the prenatal to postnatal periods, management strategies by phase, and future directions for research.

Bronchopulmonary dysplasia: what are its links to COPD?

Emerging evidence suggests that adverse early life events can affect long-term health trajectories throughout life. Preterm birth, in particular, is a significant early life event that affects approximately 10% of live births. Worldwide, prematurity is the number one cause of death in children less than 5 years of age and has been shown to disrupt normal lung development with lasting effects into adult life. Along with impaired lung development, interventions used to support gas exchange and other sequelae of prematurity can lead to the development of bronchopulmonary dysplasia (BPD). BPD is a chronic respiratory disease of infancy characterized by alveolar simplification, small airways disease, and pulmonary vascular changes. Although many survivors of BPD improve with age, survivors of BPD often have chronic lung disease characterized by airflow obstruction and intermittent pulmonary exacerbations. Long-term lung function trajectories as measured by FEV1 can be lower in children and adults with a history BPD. In this review, we discuss the epidemiology and manifestations of BPD and its long-term consequences throughout childhood and into adulthood. Available evidence suggests that disrupted lung development, genetic susceptibility and subsequent environment and infectious events that occur in prenatal and postnatal life likely increase the predisposition of children with BPD to develop early onset chronic obstructive pulmonary disease (COPD). The reviews of this paper are available via the supplemental material section.