Bronchopulmonary dysplasia: clinical aspects and preventive and therapeutic strategies

The role of nutritional interventions in the prevention and treatment of chronic lung disease of prematurity

Chronic lung disease of prematurity or bronchopulmonary dysplasia (BPD) is a common complication of preterm birth. Nutrition may affect incidence and severity of BPD. In this context, the Section on Nutrition, Gastroenterology and Metabolism, the Pulmonary Section of the European Society for Paediatric Research (ESPR) and SPR have joined forces to review the current knowledge on nutritional issues related to BPD. The aim of this narrative review is to discuss the clinical implications for nutritional practice. Nutrient deficiencies may influence pathogenesis of BPD. Adequate nutrition and growth can play a crucial role in the prevention of and recovery from BPD. Optimal nutrition strategy is an important principle, especially in the early postnatal period. As optimal energy intake in infants at risk of BPD or with evolving BPD is not yet defined, further research with well-designed studies on nutritional strategies for preterm infants with BPD is urgently needed. IMPACT: Based on current evidence it seems reasonable to recommend that BPD diagnosed infants should receive an energy supply ranging from 120 to 150 Kcal/kg/d. Exclusive MOM feed with adequate fortification should be encouraged as this is associated with a significant reduction in the risk of BPD. Suboptimal nutritional delivery is often seen in preterm infants with BPD compared to controls.

The microbiome: an integral player in immune homeostasis and inflammation in the respiratory tract

The last decade of microbiome research has highlighted its fundamental role in systemic immune and metabolic homeostasis. The microbiome plays a prominent role during gestation and into early life, when maternal lifestyle factors shape immune development of the newborn. Breast milk further shapes gut colonization, supporting the development of tolerance to commensal bacteria and harmless antigens while preventing outgrowth of pathogens. Environmental microbial and lifestyle factors that disrupt this process can dysregulate immune homeostasis, predisposing infants to atopic disease and childhood asthma. In health, the low-biomass lung microbiome, together with inhaled environmental microbial constituents, establishes the immunological set point that is necessary to maintain pulmonary immune defense. However, in disease perturbations to immunological and physiological processes allow the upper respiratory tract to act as a reservoir of pathogenic bacteria, which can colonize the diseased lung and cause severe inflammation. Studying these host-microbe interactions in respiratory diseases holds great promise to stratify patients for suitable treatment regimens and biomarker discovery to predict disease progression. Preclinical studies show that commensal gut microbes are in a constant flux of cell division and death, releasing microbial constituents, metabolic by-products, and vesicles that shape the immune system and can protect against respiratory diseases. The next major advances may come from testing and utilizing these microbial factors for clinical benefit and exploiting the predictive power of the microbiome by employing multiomics analysis approaches.

Incidence and Predictors of Bronchopulmonary Dysplasia Development and Severity Among Preterm Infants Born at 32 Weeks of Gestation or Less

Background As the most common chronic lung disease (CLD) related to premature birth, bronchopulmonary dysplasia (BPD) is associated with long-term lung disease along with cardiovascular and neurodevelopmental disorders. However, data on the incidence and predictors of BPD in Qatar are lacking. Objectives In this study, we aimed to determine the incidence of BPD among infants born at ≤ 32 weeks gestational age (GA) at our neonatal unit, and identify risk factors for the development of BPD and moderate-severe BPD. Methods This was a retrospective observational cohort study conducted at a single site: a level-III neonatal intensive care unit (NICU) in Qatar. We included 1539 neonates born at ≤ 32 weeks of gestation with birth weights of ≤ 1500 grams who were admitted to the NICU between 2017 and 2020. Univariate and multivariate logistic regression analyses were performed to identify potential factors and predictors and their possible associations with the development of BPD and moderate-severe BPD. We also applied BPD classifications to determine the variability in the incidence of BPD in our cohort according to various definitions (2001 National Institute of Child Health and Human Development (NICHD) Diagnostic Criteria, 2016 Revisions of NICHD Criteria, and 2019 Neonatal Research Network Jensen Grading). Results A total of 451 infants (29.3%) had BPD (BPD group) while 1088 (70.7%) did not (non-BPD group), and the overall incidence of BPD was 29.3%. The most relevant risk factors associated with a higher risk of developing BPD identified in the multivariate logistic regression analysis were appropriate weight for gestational age (adjusted OR (aOR) 3.67, 95%CI 2.02-6.67, P < 0.001), presence of patent ductus arteriosus (PDA) (aOR 2.61, 95%CI 1.86-3.66, P < 0.001), late-onset sepsis (aOR 2.16; 95%CI 1.29-3.62; P = 0.003), and use of invasive ventilation (aOR 1.90; 95%CI 1.35-2.69; P < 0.001). The most relevant independent risk factors associated with a higher risk for developing moderate-severe BDP were postnatal steroids (aOR 7.12, 95%CI 3.77-13.44, P < 0.001), use of inhaled nitric oxide (aOR 3.65, 95%CI 1.48-9.01, P = 0.005), use of invasive ventilation (aOR 2.13, 95%CI 1.13-4.00, P = 0.019), late-onset sepsis (aOR 2.07, 95%CI 1.10-3.91, P = 0.025), and male sex (aOR 2.04, 95%CI 1.24-3.36, P = 0.005). The difference in the distribution of BPD severity across the three different definitions of NICHD was significant (P < 0.001). Conclusion The results of this study showed that the incidence of BPD remained high in infants born at ≤ 32 weeks of gestational age and birth weight <1500 g with appropriate weight for gestational age. The presence of PDA at birth or first echocardiography, late-onset sepsis, and use of invasive ventilation were significant risk factors for the incidence of BPD. The identification of risk factors will contribute to the implementation of lung-protective strategies for at-risk infants who may benefit from potential preventive therapy.

Association of Fetal Lung Development Disorders with Adult Diseases: A Comprehensive Review

Fetal lung development is a crucial and complex process that lays the groundwork for postnatal respiratory health. However, disruptions in this delicate developmental journey can lead to fetal lung development disorders, impacting neonatal outcomes and potentially influencing health outcomes well into adulthood. Recent research has shed light on the intriguing association between fetal lung development disorders and the development of adult diseases. Understanding these links can provide valuable insights into the developmental origins of health and disease, paving the way for targeted preventive measures and clinical interventions. This review article aims to comprehensively explore the association of fetal lung development disorders with adult diseases. We delve into the stages of fetal lung development, examining key factors influencing fetal lung maturation. Subsequently, we investigate specific fetal lung development disorders, such as respiratory distress syndrome (RDS), bronchopulmonary dysplasia (BPD), congenital diaphragmatic hernia (CDH), and other abnormalities. Furthermore, we explore the potential mechanisms underlying these associations, considering the role of epigenetic modifications, transgenerational effects, and intrauterine environmental factors. Additionally, we examine the epidemiological evidence and clinical findings linking fetal lung development disorders to adult respiratory diseases, including asthma, chronic obstructive pulmonary disease (COPD), and other respiratory ailments. This review provides valuable insights for healthcare professionals and researchers, guiding future investigations and shaping strategies for preventive interventions and long-term care.

Effects of postnatal corticosteroids on lung development in newborn animals. A systematic review

BACKGROUND

Postnatal systemic corticosteroids reduce the risk of bronchopulmonary dysplasia but the effect depends on timing, dosing, and type of corticosteroids. Animal studies may provide valuable information on these variable effects. This systematic review summarizes the effects of postnatal systemic corticosteroids on lung development in newborn animals.

METHODS

A systematic search was performed in PubMed and Embase in December 2022. The protocol was published on PROSPERO (CRD42021177701).

RESULTS

Of the 202 eligible studies, 51 were included. Only newborn rodent studies met the inclusion criteria. Most studies used dexamethasone (98%). There was huge heterogeneity in study outcome measures and corticosteroid treatment regimens. Reporting of study quality indicators was mediocre and risk of bias was unclear due to poor reporting of study methodology. Meta-analysis showed that postnatal corticosteroids caused a decrease in body weight as well as persistent alveolar simplification. Subgroup analyses revealed that healthy animals were most affected.

CONCLUSION

In newborn rodents, postnatal systemic corticosteroids have a persistent negative effect on body weight and lung development. There was huge heterogeneity in experimental models, mediocre study quality, unclear risk of bias, and very small subgroups for meta-analysis which limited firm conclusions.

IMPACT

Postnatal corticosteroids reduce the risk of bronchopulmonary dysplasia but the effect depends on timing, dosing, and type of corticosteroids while the underlying mechanism of this variable effect is unknown. This is the first systematic review and meta-analysis of preclinical newborn animal studies reviewing the effect of postnatal systemic corticosteroids on lung development. In newborn rodent models, postnatal corticosteroids have a persistent negative effect on body weight and lung alveolarization, especially in healthy animals.

Investigation of the miRNA-mRNA Regulatory Circuits and Immune Signatures Associated with Bronchopulmonary Dysplasia

Background

Bronchopulmonary dysplasia (BPD) has become a major cause of morbidity and mortality in preterm infants worldwide, yet its pathogenesis and underlying mechanisms remain poorly understood. The present study sought to explore microRNA-mRNA regulatory networks and immune cells involvement in BPD through a combination of bioinformatic analysis and experimental validation.

Methods

MicroRNA and mRNA microarray datasets were obtained from the Gene Expression Omnibus (GEO) database. Differentially expressed microRNAs (DEMs) were identified in BPD patients compared to control subjects, and their target genes were predicted using miRWalk, miRNet, miRDB, and TargetScan databases. Subsequently, protein-protein interaction (PPI) and functional enrichment analyses were conducted on the target genes. 30 hub genes were screened using the Cytohubba plugin of the Cytoscape software. Additionally, mRNA microarray data was utilized to validate the expression of hub genes and to perform immune infiltration analysis. Finally, real-time PCR (RT-PCR), immunohistochemistry (IHC), and flow cytometry were conducted using a mouse model of BPD to confirm the bioinformatics findings.

Results

Two DEMs (miR-15b-5p and miR-20a-5p) targeting genes primarily involved in the regulation of cell cycle phase transition, ubiquitin ligase complex, protein serine/threonine kinase activity, and MAPK signaling pathway were identified. APP and four autophagy-related genes (DLC1, PARP1, NLRC4, and NRG1) were differentially expressed in the mRNA microarray dataset. Analysis of immune infiltration revealed significant differences in levels of neutrophils and naive B cells between BPD patients and control subjects. RT-PCR and IHC confirmed reduced expression of APP in a mouse model of BPD. Although the proportion of total neutrophils did not change appreciably, the activation of neutrophils, marked by loss of CD62L, was significantly increased in BPD mice.

Conclusion

Downregulation of APP mediated by miR-15b-5p and miR-20a-5p may be associated with the development of BPD. Additionally, increased CD62L- neutrophil subset might be important for the immune-mediated injury in BPD.

A Review of the Use of Extracellular Vesicles in the Treatment of Neonatal Diseases: Current State and Problems with Translation to the Clinic

Neonatal disorders, particularly those resulting from prematurity, pose a major challenge in health care and have a significant impact on infant mortality and long-term child health. The limitations of current therapeutic strategies emphasize the need for innovative treatments. New cell-free technologies utilizing extracellular vesicles (EVs) offer a compelling opportunity for neonatal therapy by harnessing the inherent regenerative capabilities of EVs. These nanoscale particles, secreted by a variety of organisms including animals, bacteria, fungi and plants, contain a repertoire of bioactive molecules with therapeutic potential. This review aims to provide a comprehensive assessment of the therapeutic effects of EVs and mechanistic insights into EVs from stem cells, biological fluids and non-animal sources, with a focus on common neonatal conditions such as hypoxic-ischemic encephalopathy, respiratory distress syndrome, bronchopulmonary dysplasia and necrotizing enterocolitis. This review summarizes evidence for the therapeutic potential of EVs, analyzes evidence of their mechanisms of action and discusses the challenges associated with the implementation of EV-based therapies in neonatal clinical practice.

Transforming neonatal care with artificial intelligence: challenges, ethical consideration, and opportunities

Artificial intelligence (AI) offers tremendous potential to transform neonatology through improved diagnostics, personalized treatments, and earlier prevention of complications. However, there are many challenges to address before AI is ready for clinical practice. This review defines key AI concepts and discusses ethical considerations and implicit biases associated with AI. Next we will review literature examples of AI already being explored in neonatology research and we will suggest future potentials for AI work. Examples discussed in this article include predicting outcomes such as sepsis, optimizing oxygen therapy, and image analysis to detect brain injury and retinopathy of prematurity. Realizing AI's potential necessitates collaboration between diverse stakeholders across the entire process of incorporating AI tools in the NICU to address testability, usability, bias, and transparency. With multi-center and multi-disciplinary collaboration, AI holds tremendous potential to transform the future of neonatology.

Montelukast Sodium to Prevent and Treat Bronchopulmonary Dysplasia in Very Preterm Infants: A Quasi-Randomized Controlled Trial

Bronchopulmonary dysplasia (BPD) is the most common chronic lung disease in preterm infants and lacks effective methods for prevention and treatment. The aim of this study is to explore the efficacy and safety of montelukast in preventing or treating BPD in preterm infants. The preterm infants with BPD risk factors were divided randomly into a montelukast group and a control group. In the montelukast group, preterm infants were given 1 mg/kg of montelukast sodium daily. There was no placebo in the control group. There was no significant difference in the incidence of moderate or severe BPD between the two groups (31.8% vs. 35%). The duration of respiratory support in the montelukast group was shorter than that in the control group (36.4 ± 12.8 d vs. 43.1 ± 15.9 d, p = 0.037). The pulmonary severity score (PSS) at 21 days of life in the montelukast group was significantly lower than that in the control group (0.56 ± 0.13 vs. 0.62 ± 0.14, p = 0.048). There were no significant differences in the duration of mechanical ventilation, length of stay, hospitalization expenses, or incidence of adverse events. Although montelukast cannot alleviate the severity of BPD, it may shorten the duration of respiratory support and decrease the PSS in very preterm infants. There were no significant adverse drug events associated with montelukast treatment.

A Systematic Review: Is Early Fluid Restriction in Preterm Neonates Going to Prevent Bronchopulmonary Dysplasia?

Preterm birth causes constant challenges, with bronchopulmonary dysplasia (BPD) being a major concern. Immediately after birth, it takes time to establish feeding between the mother and the premature baby. During this time, the telological shifting of fluid from extracellular space to intracellular space will help the baby; this transition should be smooth. Both normal physiologic changes and pathophysiologic events are capable of disrupting this delicate fluid shifting that occurs in very low-birth-weight infants during the first week of life. The immaturity of the renal system and evaporative losses complicate this process. This lack of fluid displacement can be associated with an increased amount of water in the lungs and reduced lung compliance. This can lead to the need for more ventilatory support and a higher oxygen requirement, which, in turn, leads to lung damage. The fluid restriction is also associated with complications such as severe dehydration, intracranial hemorrhage, and bilirubin toxicity. However, the administration of large amounts of fluid and salt is associated with an increased incidence of patent ductus arteriosus, BPD, necrotizing enterocolitis, and intraventricular hemorrhage. There were studies conducted in both the pre-surfactant and surfactant eras that were inconclusive regarding fluid restriction in BPD. We only included very recent studies. This systematic review attempts to summarize the current evidence, focusing on the efficacy and safety of early fluid management in preterm infants. This reduces the risk of BPD and improves outcomes for premature infants. As we know, intact survival is very important. Our review supported the early fluid restriction.

Regulating NLRP3 Inflammasome-Induced Pyroptosis via Nrf2: TBHQ Limits Hyperoxia-Induced Lung Injury in a Mouse Model of Bronchopulmonary Dysplasia

Nuclear factor e2-related factor 2 (Nrf2) plays a key role in cellular resistance to oxidative stress injury. Oxidative stress injury, caused by Nrf2 imbalance, results in increased pyroptosis, DNA damage, and inflammatory activation, which may lead to the arrest of alveolar development and bronchopulmonary dysplasia (BPD) in premature infants under hyperoxic conditions. We established a BPD mouse model to investigate the effects of tert-butylhydroquinone (TBHQ), an Nrf2 activator, on oxidative stress injury, pyroptosis, NLRP3 inflammasome activation, and alveolar development. TBHQ reduced abnormal cell death in the lung tissue of BPD mice and restored the number and normal structure of the alveoli. TBHQ administration activated the Nrf2/heme oxygenase-1 (HO-1) signaling pathway, resulting in the decrease in the following: reactive oxygen species (ROS), activation of the NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome, and IL-18 and IL-1β expression and activation, as well as inhibition of pyroptosis. In contrast, after Nrf2 gene knockout in BPD mice, there was more severe oxidative stress injury and cell death in the lungs, there were TUNEL + and NLRP3 + co-positive cells in the alveoli, the pyroptosis was significantly increased, and the development of alveoli was significantly blocked. We demonstrated that TBHQ may promote alveolar development by enhancing Nrf2-induced antioxidation in the lung tissue of BPD mice and that the decrease in the NLRP3 inflammasome and pyroptosis caused by Nrf2 activation may be the underlying mechanism. These results suggest that TBHQ is a promising treatment for lung injury in premature infants with hyperoxia.

Impact of advanced maternal age on neonatal morbidity: a systematic review

OBJECTIVE

This systematic review aimed to understand the impact of advanced maternal age (AMA) on the neonatal morbidity, based on the available scientific evidence.

METHODS

A systematic search was conducted on 22 November 2021, using the PubMed and Scopus databases to identify studies that compared the morbidity of neonates delivered to AMA mothers with that of neonates delivered to non-AMA mothers.

RESULTS

Sixteen studies that evaluated the effect of AMA on the neonatal morbidity were included in this review. Nine of these studies found some association between AMA and increased neonatal morbidity (with two of them only reporting an increase in asymptomatic hypoglycemia, and one only reporting an association in twins), six found no association between AMA and neonatal morbidity and one study found a decrease in morbidity in preterm neonates. The studies that found an increase in overall neonatal morbidity with AMA considered older ages for the definition of AMA, particularly ≥40 and ≥45 years.

CONCLUSION

The current evidence seems to support a lack of association between AMA and the neonatal morbidity of the delivered neonates. However, more studies focusing on the neonatal outcomes of AMA pregnancies are needed to better understand this topic.

Self-assembled miR-134-5p inhibitor nanoparticles ameliorate experimental bronchopulmonary dysplasia (BPD) via suppressing ferroptosis

Bronchopulmonary dysplasia (BPD) is a chronic lung disease in premature infants with increased levels of reactive oxygen species (ROS) and ferroptosis. Herein, we designed a peptide-based nanoparticle to deliver therapeutic molecules to pulmonary, thereby ameliorating BPD. The BPD-induced damages of lung tissues were detected by H&E and immunohistochemistry staining. Inflammatory cytokines, Fe2+, and ROS levels were quantified by the indicated kits, respectively. The targeting relationship was verified by luciferase reporter assay and pull-down assay. Subsequently, self-assembled miR-134-5p inhibitor nanoparticles with pulmonary epithelial cell-targeting were synthesized. The characteristics were detected by transmission electron microscopy, luminescence imaging, and dynamic light scattering. A significant ferroptosis was observed in the BPD mice. The protein level of GPX4 was decreased significantly compared to the control group. Constantly, miR-134-5p showed positive regulation on ferroptosis by targeting GPX4. The designed nanoparticles were mainly accumulated in the lung region. Besides, it ameliorated experimental bronchopulmonary dysplasia via suppressing ferroptosis, in vivo and in vitro. Our findings provided a miR-134-5p/GPX4 axis in regulating ferroptosis of BPD and prompted the potential of applying the peptide-based nanoparticle to BPD treatment.

Management of bronchopulmonary dysplasia in Japan: A nationwide survey

BACKGROUND

The incidence of bronchopulmonary dysplasia (BPD) and respiratory management practices for extremely low birth weight infants (ELBWIs) widely vary among institutions and countries.

AIMS

To clarify the variation and characteristics of the current practices of Japanese neonatologists managing patients with BPD.

STUDY DESIGN

Questionnaire-based survey.

PARTICIPANTS

Level II and III perinatal centers certified by the Japan Society of Perinatal and Neonatal Medicine.

OUTCOME MEASURES

Policies of the neonatal intensive care units (NICUs) regarding respiratory care and medications for BPD prevention and treatment.

RESULTS

A total of 76 % of facilities (207/274) responded to our survey. The response rates of level III and II facilities were 91 % (102/112) and 35 % (105/296), respectively. INtubation-SURfactant-Extubation and Less Invasive Surfactant Administration methods were performed in 23 % (47/206) and 1 % (3/206) of facilities, respectively. For the prophylactic purpose, systemic and inhaled steroids were administered "frequently" or "occasionally" in 14 % (28/205) and 42 % (86/204) of NICUs, respectively. For the therapeutic purpose, systemic and inhaled steroids were administered "frequently" or "occasionally" in 84 % (171/204) and 29 % (59/204) of NICUs, respectively. Approximately half of the NICUs (99/202) used volume-targeted ventilation (VTV) "frequently" or "occasionally" in progressing BPD. High-frequency oscillation ventilation (HFOV) was used for progressing BPD "frequently" and "occasionally" in 89 % (180/202) of the facilities.

CONCLUSIONS

Our study provided an overview and characteristics of BPD management in Japan in recent years. Noninvasive approaches with surfactant administration remain not widely used in Japan. HFOV is a widely accepted management for progressing BPD.

Risk factors for bronchopulmonary dysplasia infants with respiratory score greater than four: a multi-center, prospective, longitudinal cohort study in China

Bronchopulmonary dysplasia (BPD) is the most common complication of prematurity involving both pre- and post-natal factors. A large, prospective, longitudinal cohort study was conducted to determine whether inflammation-related factors are associated with an increased risk of BPD in preterm infants who were born at a gestational age < 32 weeks, < 72 h after birth and respiratory score > 4. The study included infants from 25 participating hospitals in China between March 1, 2020 and March 31, 2022. The primary outcomes were BPD and severity of BPD at 36 weeks post-menstrual age. A total of 1362 preterm infants were enrolled in the study. After exclusion criteria, the remaining 1088 infants were included in this analysis, of whom, 588 (54.0%) infants were in the BPD group and 500 (46.0%) were in the non-BPD group. In the BPD III model, the following six factors were identified: birth weight (OR 0.175, 95% CI 0.060-0.512; p = 0.001), surfactant treatment (OR 8.052, 95% CI 2.658-24.399; p < 0.001), mean airway pressure (MAP) ≥ 12 cm H2O (OR 3.338, 95% CI 1.656-6.728; p = 0.001), late-onset sepsis (LOS) (OR 2.911, 95% CI 1.514-5.599; p = 0.001), ventilator-associated pneumonia (VAP) (OR 18.236, 95% CI 4.700-70.756; p < 0.001) and necrotizing enterocolitis (NEC) (OR 2.725, 95% CI 1.182-6.281; p = 0.019). Premature infants remained at high risk of BPD and with regional variation. We found that post-natal inflammation-related risk factors were associated with an increased risk of severe BPD, including LOS, VAP, NEC, MAP ≥ 12 cm H2O and use of surfactant.

A predictive model for preterm infants with bronchopulmonary dysplasia based on ferroptosis-related lncRNAs

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the most challenging chronic lung disease for prematurity, with difficulties in early identification. Given lncRNA emerging as a novel biomarker and the regulator of ferroptosis, this study aims to develop a BPD predictive model based on ferroptosis-related lncRNAs (FRLs).

METHODS

Using a rat model, we firstly explored mRNA levels of ferroptosis-related genes and ferrous iron accumulation in BPD rat lungs. Subsequently, a microarray dataset of umbilical cord tissue from 20 preterm infants with BPD and 34 preterm infants without BPD were downloaded from the Gene Expression Omnibus databases. Random forest and LASSO regression were conducted to identify diagnostic FRLs. Nomogram was used to construct a predictive BPD model based on the FRLs. Finally, umbilical cord blood lymphocytes of preterm infants born before 32 weeks gestational age and term infants were collected and determined the expression level of diagnostic FRLs by RT-qPCR.

RESULTS

Increased iron accumulation and several dysregulated ferroptosis-associated genes were found in BPD rat lung tissues, indicating that ferroptosis was participating in the development of BPD. By exploring the microarray dataset of preterm infants with BPD, 6 FRLs, namely LINC00348, POT1-AS1, LINC01103, TTTY8, PACRG-AS1, LINC00691, were determined as diagnostic FRLs for modeling. The area under the receiver operator characteristic curve of the model was 0.932, showing good discrimination of BPD. In accordance with our analysis of microarray dataset, the mRNA levels of FRLs were significantly upregulated in umbilical cord blood lymphocytes from preterm infants who had high risk of BPD.

CONCLUSION

The incorporation of FRLs into a predictive model offers a non-invasive approach to show promise in improving early detection and management of this challenging chronic lung disease in premature infant, enabling timely intervention and personalized treatment strategies.

CircABPD1 alleviates oxidative lung injury of bronchopulmonary dysplasia through regulating miR-330-3p/HIF1α axis

In the NICU, bronchopulmonary dysplasia (BPD) is a concerning common respiratory complication in preterm and low birth-weight infants. Clinical studies have confirmed that human milk has an important nutritional role for children with BPD, therefore, dentification of beneficial components in human milk that prevent BPD is urgently needed. Our previous work showed that human milk exosomes (HM-Exos) could inhibit apoptosis of alveolar type II epithelial cells (AT II), and the circular RNA (circRNA)-circABPD1 were highly expressed in preterm colostrum milk exosomes. Exosomes transport circRNAs that are stable and may exert anti-inflammatory and immune effects attracted the attention of researchers, but the role and mechanism of human milk exosome-derived circABPD1 in BPD remains unclear. Here, we constructed BPD in vivo and in vitro models through exposure to hyperoxia, verified the effect of circABPD1 and revealed its mechanism through rescue experiments. We found that circABPD1 had circRNA properties, and overexpression of circABPD1 could improve reduced alveolar number, enlarged the alveolar linear intercept in vivo models of BPD, promote cell proliferation, reduce oxidative stress levels and alleviate lung epithelial cell damage in vivo and in vitro models. Mechanistically, circABPD1 targets miR-330-3p and regulates the expression of HIF1α. These results suggest that circABPD1 can improve the pathologoical changes of bronchopulmonary dysplasia, promote cell proliferation, inhibit oxidative stress level, and alleviate lung injury by targeting the miR-330-3p/HIF1α axis, which provides a new idea for the prevention and treatment of bronchopulmonary dysplasia.

Integration of transcriptomics reveals ferroptosis-related signatures and immune cell infiltration in bronchopulmonary dysplasia

Ferroptosis has emerged as a significant factor in the development of bronchopulmonary dysplasia (BPD). Nevertheless, our understanding of the potential involvement of ferroptosis-related genes (FRGs) in BPD remains incomplete. In this study, we leveraged the Gene Expression Omnibus (GEO) database to investigate this aspect. We identified 20 differentially expressed FRGs that are associated with BPD, shedding light on their potential role in the condition.LASSO along with SVM-RFE algorithms found that 12 genes: MEG3, ACSL1, DPP4, GALNT14, MAPK14, CD82, SMPD1, NR1D1, PARP3, ACVR1B, H19, and SLC7A11 were closely related to ferroptosis modulation and immunological response. These genes were used to create a nomogram with good predictive power and were found to be involved in BPD-linked pathways. In addition, the marker genes-based prediction model performed well in external validation data sets. The study also showed a significance between BPD and control samples in terms of immune cell infiltration. These findings may help improve our understanding of FRGs in BPD and lead to the development of more effective immunotherapies.

[Clinical characteristics and pathogens of infancy lower respiratory tract infections in infants with bronchopulmonary dysplasia]

OBJECTIVES

To study the clinical characteristics and pathogen features of infants with bronchopulmonary dysplasia (BPD) who were readmitted during infancy due to lower respiratory tract infections.

METHODS

A retrospective analysis was conducted on 128 preterm infants with BPD who were admitted for lower respiratory tract infections in Qingdao Women and Children's Hospital from January 2020 to December 2022. An equal number of non-BPD preterm infants admitted during the same period were selected as controls. General information, clinical characteristics, lung function parameters, and respiratory pathogen results were compared between the two groups.

RESULTS

Compared with the non-BPD group, the BPD group had a lower gestational age and birth weight, were more likely to experience shortness of breath, wheezing, and cyanosis, and had a longer duration of wheezing relief (P<0.05). Compared with the non-BPD group, the BPD group had lower lung function parameters, including tidal volume per kilogram of body weight, ratio of time to peak tidal expiratory flow to total expiratory time, ratio of volume at peak tidal expiratory flow to expiratory tidal volume, tidal expiratory flow at 25%, 50%, and 75% of tidal volume, and increased respiratory rate (P<0.05). The detection rates of gram-negative bacteria, such as Klebsiella pneumoniae and Acinetobacter baumannii, were higher in the BPD group than in the non-BPD group (P<0.05).

CONCLUSIONS

Infants with BPD who develop infancy lower respiratory tract infections require closer attention to the clinical characteristics such as shortness of breath, wheezing, and cyanosis. Lung function is characterized by obstructive changes and small airway dysfunction. Gram-negative bacteria, including Klebsiella pneumoniae and Acinetobacter baumannii, are more likely to be detected as respiratory pathogens.

Tat-P combined with GAPR1 releases Beclin1 to promote autophagy and improve Bronchopulmonary dysplasia model

Long-term exposure to hyperoxia can leading to the bronchopulmonary dysplasia (BPD). The progression of BPD is primarily driven by the apoptosis of alveolar epithelial cells, and the regulation of autophagy has an impact on apoptosis. This study aims to investigate the therapeutic potential and underlying mechanism of an autophagy-promoting peptide (Tat-P) in ameliorating BPD. In vitro experiments demonstrated that Tat-P promoted autophagy and partially prevented apoptosis caused by exposure to hyperoxia. Further investigation into the mechanism revealed that Tat-P competitively binds to GAPR1, displacing the Beclin1 protein and thereby inhibiting the apoptosis. In vivo experiments conducted on Sprague-Dawley pups exposed to high oxygen levels demonstrated that Tat-P promoted autophagy and reduced apoptosis in lung tissues and ameliorated BPD-related phenotypes. Our findings elucidate the underlying mechanisms and effects of Tat-P in enhancing autophagy and preventing apoptosis. This study presents an approach for the prevention and treatment of BPD.

Effect of Breast Milk on the Frequency of Bronchopulmonary Dysplasia in Very Low Birth Weight Premature Infants: A Meta-analysis

Purpose: To analyze the effect of different feeding types on bronchopulmonary dysplasia (BPD) in very low birth weight preterm infants. Methods: The Cochrane Library, PubMed, Embase, China National Knowledge Infrastructure (CNKI), Wanfang Data Knowledge Service Platform, China Biomedical Literature Database (CBM) were searched for literature related to breastfeeding and BPD, with a search period from their inception to January 2023. Two researchers independently screened the literature, extracted data, and assessed the quality of included studies before analyzing the data using Stata16 and RevMan5.4.1 software. Results: A total of 17 studies were included. The results showed that there was no significant difference in the frequency of BPD between human milk (HM) and donor human milk (DHM) (OR = 0.54, 95% CI: 0.29-1.03, p = 0.07). However, DHM had a significant effect in reducing the frequency of BPD compared to preterm formula (PF) (OR = 0.62, 95% CI: 0.41-0.94, p = 0.02). Exclusive HM also had a significant effect in reducing the frequency of BPD compared to exclusive PF (OR = 0.51, 95% CI: 0.34-0.78, p = 0.002), as well as compared to any PF (OR = 0.57, 95% CI: 0.37-0.88, p = 0.01). Furthermore, mainly (>50%) HM had a significant effect in reducing the frequency of BPD compared to mainly PF (OR = 0.72, 95% CI: 0.55-0.93, p = 0.01). However, there was no statistically significant difference between any HM and exclusive PF (OR = 0.88, 95% CI: 0.62-1.23, p = 0.46). Conclusions: Our study findings suggest that both HM and DHM have a significant protective effect in reducing the frequency of BPD occurrence compared to PF. Furthermore, even when the amount of HM is insufficient, feeding more than 50% of the HM volume still provides a protective effect against the frequency of BPD. Therefore, we recommend feeding infants with more than 50% of HM to harness the protective effect of HM against BPD occurrence.

Targeting miR-146b-5p to Regulate KDM6B Expression Aggravates Bronchopulmonary Dysplasia

miR-146b-5p has been studied to be highly expressed in bronchopulmonary dysplasia (BPD), but whether it is involved in regulating the process of BPD in premature infants remains unclear. This study was to explore miR-146b-5p in premature BPD and reveal its molecular mechanism. BPD mouse model and high-oxygen MLE-12 cell model were established. HE staining, TUNEL staining, and IF staining were conducted to evaluate the pathological injury and protein expression in mouse lung tissue. LDH assay, MMT assay, and flow cytometry were achieved to evaluate cytotoxicity, cell viability, and apoptosis. ELISA and immunoblotting were performed to evaluate inflammatory cytokines and Wnt pathway proteins in lung tissues and cells. Dual-luciferase reporter assay and RIP assay were needed to examine the targeting relationship between miR-146b-5p and KDM6B. miR-146b-5p was abundantly expressed in BPD and KDM6B was lowly expressed. miR-146b-5p knockdown improved hyperoxia-induced lung epithelial cell inflammation and apoptosis in both models. miR-146b-6p upregulation or KDM6B downregulation aggravated hyperoxia-induced inflammation and apoptosis of lung epithelial cells. This effect of overexpressing miR-146b-5p was rescued by forcing KDM6B. MiR-146b-5p activated Wnt signaling by regulating KDM6B. miR-146b-5p activates the Wnt pathway through targeted regulation of KDM6B, thereby aggravating hyperoxia-induced inflammation and apoptosis of lung epithelial cells.

Temporal profile of adverse drug reactions and associated clinical factors: a prospective observational study in a neonatal intensive care unit

OBJECTIVE

Although adverse drug reactions (ADRs) are quite common in hospitalised neonates, pharmacovigilance activities in this public are still incipient. This study aims to characterise ADRs in neonates in a neonatal intensive care unit (NICU), identifying causative drugs, temporal profile and associated factors.

DESIGN

Prospective observational study.

SETTING

NICU of a public maternity hospital in Natal/Brazil.

PARTICIPANTS

All neonates admitted to the NICU for more than 24 hours and using at least one medication were followed up during the time of hospitalisation.

PRIMARY OUTCOME MEASURES

Incidence rate and risk factors for ADRs. The ADRs were detected by an active search in electronic medical records and analysis of spontaneous reports in the hospital pharmacovigilance system.

RESULTS

Six hundred neonates were included in the study, where 118 neonates had a total of 186 ADRs. The prevalence of ADRs at the NICU was 19.7% (95% CI 16.7% to 23.0%). The most common ADRs were tachycardia (30.6%), polyuria (9.1%) and hypokalaemia (8.6%). Tachycardia (peak incidence rate: 57.1 ADR/1000 neonates) and hyperthermia (19.1 ADR/1000 neonates) predominated during the first 5 days of hospitalisation. The incidence rate of polyuria and hypokalaemia increased markedly after the 20th day, with both reaching a peak of 120.0 ADR/1000 neonates. Longer hospitalisation time (OR 0.018, 95% CI 0.007 to 0.029; p<0.01) and number of prescribed drugs (OR 0.127, 95% CI 0.075 to 0.178; p<0.01) were factors associated with ADRs.

CONCLUSION

ADRs are very common in NICU, with tachycardia and hyperthermia predominant in the first week of hospitalisation and polyuria and hypokalaemia from the third week onwards.

Human Milk Feeding Is Associated with Decreased Incidence of Moderate-Severe Bronchopulmonary Dysplasia in Extremely Preterm Infants

BACKGROUND

An increased rate of bronchopulmonary dysplasia (BPD) is reported in extremely preterm infants. A potential role of human milk feeding in protecting against this condition has been suggested.

METHODS

A retrospective descriptive study was conducted based on data about morbidity in the population of infants born between 22+0 and 26+6 weeks of gestation, included in the Spanish network SEN1500 during the period 2004-2019 and discharged alive. The primary outcome was moderate-severe BPD. Associated conditions were studied, including human milk feeding at discharge. The temporal trends of BPD and human milk feeding rates at discharge were also studied.

RESULTS

In the study population of 4341 infants, the rate of moderate-severe BPD was 43.7% and it increased to >50% in the last three years. The factors significantly associated with a higher risk of moderate-severe BPD were birth weight, male sex, high-frequency oscillatory ventilation, duration of invasive mechanical ventilation, inhaled nitric oxide, patent ductus arteriosus, and late-onset sepsis. Exclusive human milk feeding and any amount of human milk at discharge were associated with a lower incidence of moderate-severe BPD (OR 0.752, 95% CI 0.629-0.901 and OR 0.714, 95% CI 0.602-0.847, respectively). During the study period, the proportion of infants with moderate-severe BPD fed any amount of human milk at discharge increased more than twofold. And the proportion of infants with moderate-severe BPD who were exclusively fed human milk at discharge increased at the same rate.

CONCLUSIONS

Our work shows an inverse relationship between human milk feeding at discharge from the neonatal unit and the occurrence of BPD.

Longitudinal development of the airway metagenome of preterm very low birth weight infants during the first two years of life

Preterm birth is accompanied with many complications and requires severe therapeutic regimens at the neonatal intensive care unit. The influence of the above-mentioned factors on the premature-born infants' respiratory metagenome or more generally its maturation is unknown. We therefore applied shotgun metagenome sequencing of oropharyngeal swabs to analyze the airway metagenome development of 24 preterm infants from one week postpartum to 15 months of age. Beta diversity analysis revealed a distinct clustering of airway microbial communities from hospitalized preterms and samples after hospital discharge. At nine and 15 months of age, the preterm infants lost their hospital-acquired individual metagenome signatures towards a common taxonomic structure. However, ecological network analysis and Random Forest classification of cross-sectional data revealed that by this age the preterm infants did not succeed in establishing the uniform and stable bacterial community structures that are characteristic for healthy full-term infants.

METTL3 promotes hyperoxia-induced pyroptosis in neonatal bronchopulmonary dysplasia by inhibiting ATG8-mediated autophagy

OBJECTIVES

N6-Methyladenosine (m6A) modification plays a vital role in lung disorders. However, the potential of m6A in neonatal Bronchopulmonary Dysplasia (BPD) has not been reported. This study aimed to investigate the roles of METTL3 in BPD.

METHODS

BPD models were established by hyperoxia in vivo and in vitro. Histological analysis was determined using HE staining. Gene expression was determined using Western blotting, qRT-PCR, and immunofluorescence. The release of IL-1β and IL-18 was detected using ELISA. The m6A sites of ATG8 were predicted by SCRAPM and verified by MeRIP assay. The location of GSDMD and ATG8 was determined by FISH assay. The interaction between ATG8 and GSDMD was detected using Coimmunoprecipitation (Co-IP). Cell pyroptosis was determined using flow cytometry and TUNEL assays.

RESULTS

METTL3 was overexpressed in BPD, which was accompanied by an increase in m6A levels. Interestingly, METTL3 suppressed hyperoxia-mediated damage and pyroptosis in BEAS-2B cells and promoted cell autophagy. METTL3-mediated m6A modification of ATG8 suppressed its expression and disrupted the interaction between ATG8 and GSDMD. However, autophagy inhibition induced pyroptosis in BEAS-2B cells. In vivo assays showed that METTL3-mediated autophagy inhibition induced a decrease in the radial alveolar count and an increase in the mean linear intercept and promoted cell pyroptosis.

CONCLUSION

In conclusion, METTL3-mediated cell pyroptosis promotes BPD by regulating the m6A modification of ATG8. This may provide new insight into the development of BPD.

[Association between early parenteral nutrition and the development of bronchopulmonary dysplasia in preterm infants]

OBJECTIVES

To study the relationship between early parenteral nutrient intake and the development of bronchopulmonary dysplasia (BPD) in preterm infants with gestational age less than 32 weeks who could not receive enteral nutrition within one week after birth.

METHODS

A retrospective study was conducted on preterm infants born between October 2017 and August 2022 with gestational age less than 32 weeks who were admitted to the Neonatal Intensive Care Unit in Children's Hospital of Soochow University within 24 hours after birth and relied solely on parenteral nutrition within the first week of life. The study population included 79 infants with BPD and 73 infants without BPD. Clinical data during hospitalization were compared between the two groups.

RESULTS

The proportions of infants with weight loss of more than 10% after birth, extrauterine growth retardation, and parenteral nutrition-associated cholestasis in the BPD group were higher than in the non-BPD group (P<0.05). The time to regain birth weight, time to achieve full enteral feeding, and corrected gestational age at discharge were longer in the BPD group than in the non-BPD group. The Z-scores of physical growth at corrected gestational age of 36 weeks were lower in the BPD group than in the non-BPD group (P<0.05). The BPD group had a higher fluid intake and a lower calories intake in the first week than the non-BPD group (P<0.05). The starting dose and total amount of amino acids, glucose, and lipids in the first week were lower in the BPD group than in the non-BPD group (P<0.05). The BPD group had a higher glucose-to-lipid ratio on the third day and higher energy-to-nitrogen and glucose-to-lipid ratios on the seventh day after birth than the non-BPD group (P<0.05).

CONCLUSIONS

Preterm infants with BPD had lower intake of amino acids and lipids and a lower proportion of calories provided by amino acids and lipids in the first week of life, which suggests an association between early parenteral nutrition intake and the development of BPD.

Involvement of HIF1 stabilization and VEGF signaling modulated by Grx-1 in murine model of bronchopulmonary dysplasia

Hypoxia inducible factor (HIF)-1α could be stabilized by Grx1 deletion, which is implicated critical in the pathogenesis of bronchopulmonary dysplasia (BPD). Until now, the stabilization of HIF-1α by glutathionylation to regulate the pulmonary microcirculation in BPD is not well addressed. In this study, we investigated whether the HIF-1α stabilization modulated by Grx1 ablation could ameliorate the pathological changes in the mouse model of BPD, including angiogenesis and alveolar formation. We found that depletion of Grx1 increased levels of GSH-protein adducts, which was associated with the improvement in the numbers of alveoli, the capillary density in the pulmonary microcirculation and the survival rate in the littermates with hyperoxic exposure. Grx1 ablation could promote HIF-1α glutathionylation by increasing GSH adducts to stabilize HIF-1α and to induce VEGF-A production in the lung tissue. The above phenotype of capillary density and VEGF-A production was removed by the pharmacological administration of YC-1, the HIF-1α inhibitor, suggesting the HIF-1α dependent manner for pulmonary microcirculatory perfusion. These data indicate that HIF-1α stabilization plays an critical role in modification pulmonary microcirculatory perfusion, which is associated with the pathological damage under hyperoxic conditions, suggesting that targeting with HIF-1α stabilization should be a potential clinical and therapeutic strategy for BPD treatment.

Melatonin Protects Against Hyperoxia-Induced Apoptosis in Alveolar Epithelial type II Cells by Activating the MT2/PI3K/AKT/ETS1 Signaling Pathway

PURPOSE

Hyperoxia-induced apoptosis in alveolar epithelial type II cells (AECIIs) plays a critical role in the development of bronchopulmonary dysplasia (BPD). Melatonin has been shown to improve BPD. However, the protective effect of melatonin on hyperoxia-induced apoptosis in AECIIs and the precise mechanisms involved remain unclear.

METHODS

Human alveolar epithelial type II A549 cells were treated with hyperoxia as an in vitro model to investigate the antiapoptotic mechanism of melatonin. CCK-8 assays were performed to investigate the viability of A549 cells. Hoechst 33,258 staining was carried out to quantify apoptosis in A549 cells. The protein expression levels of E26 oncogene homolog 1 (ETS1), Bcl-2, Bax, Bim, Wnt, β-catenin, AKT and phosphorylated AKT were measured by western blotting. LY294002, SC79 and the downregulation of ETS1, melatonin receptor 1 (MT1) and MT2 with specific siRNAs were used to investigate the role of the PI3K/AKT pathway, ETS1, MT1 and MT2 in hyperoxia-induced apoptosis in A549 cells.

RESULTS

Melatonin prevented hyperoxia-induced apoptosis in A549 cells, and the upregulation of E26 oncogene homolog 1 (ETS1) contributed to the antiapoptotic effect of melatonin. Melatonin activated the PI3K/AKT axis, which led to ETS1 upregulation and inhibited apoptosis in hyperoxia-exposed A549 cells. Furthermore, melatonin-induced activation of the PI3K/AKT axis, upregulation of ETS1 and inhibition of apoptosis were reversed by melatonin receptor 2 (MT2) siRNA in hyperoxia-exposed A549 cells.

CONCLUSION

Melatonin prevents hyperoxia-induced apoptosis by activating the MT2/PI3K/AKT/ETS1 axis in alveolar epithelial cells.

Oxygen toxicity causes cyclic damage by destabilizing specific Fe-S cluster-containing protein complexes

Oxygen is toxic across all three domains of life. Yet, the underlying molecular mechanisms remain largely unknown. Here, we systematically investigate the major cellular pathways affected by excess molecular oxygen. We find that hyperoxia destabilizes a specific subset of Fe-S cluster (ISC)-containing proteins, resulting in impaired diphthamide synthesis, purine metabolism, nucleotide excision repair, and electron transport chain (ETC) function. Our findings translate to primary human lung cells and a mouse model of pulmonary oxygen toxicity. We demonstrate that the ETC is the most vulnerable to damage, resulting in decreased mitochondrial oxygen consumption. This leads to further tissue hyperoxia and cyclic damage of the additional ISC-containing pathways. In support of this model, primary ETC dysfunction in the Ndufs4 KO mouse model causes lung tissue hyperoxia and dramatically increases sensitivity to hyperoxia-mediated ISC damage. This work has important implications for hyperoxia pathologies, including bronchopulmonary dysplasia, ischemia-reperfusion injury, aging, and mitochondrial disorders.

Circular RNAs in the Origin of Developmental Lung Disease: Promising Diagnostic and Therapeutic Biomarkers

Circular RNA (circRNA) is a newly discovered noncoding RNA that regulates gene transcription, binds to RNA-related proteins, and encodes protein microRNAs (miRNAs). The development of molecular biomarkers such as circRNAs holds great promise in the diagnosis and prognosis of clinical disorders. Importantly, circRNA-mediated maternal-fetus risk factors including environmental (high altitude), maternal (preeclampsia, smoking, and chorioamnionitis), placental, and fetal (preterm birth and low birth weight) factors are the early origins and likely to contribute to the occurrence and progression of developmental and pediatric cardiopulmonary disorders. Although studies of circRNAs in normal cardiopulmonary development and developmental diseases have just begun, some studies have revealed their expression patterns. Here, we provide an overview of circRNAs’ biogenesis and biological functions. Furthermore, this review aims to emphasize the importance of circRNAs in maternal-fetus risk factors. Likewise, the potential biomarker and therapeutic target of circRNAs in developmental and pediatric lung diseases are explored.

Hyperoxia exposure upregulates Dvl-1 and activates Wnt/β-catenin signaling pathway in newborn rat lung

BACKGROUND

Bronchopulmonary dysplasia is a serious and lifelong pulmonary disease in premature neonates that influences around one-quarter of premature newborns. The wingless-related integration site /β-catenin signaling pathway, which is abnormally activated in the lungs with pulmonary fibrosis, affects cell differentiation and lung development.

METHODS

Newborn rats were subjected to hyperoxia exposure. Histopathological changes to the lungs were evaluated through immunohistochemistry, and the activation of disheveled and Wnt /β-catenin signaling pathway components was assessed by Western blotting and real-time PCR. The abilities of proliferation, apoptosis and migration were detected by Cell Counting Kit-8, flow cytometry and scratch wound assay, respectively.

RESULTS

Contrasting with normoxic lungs, hyperoxia-exposed lungs demonstrated larger alveoli, fewer alveoli and thicker alveolar septa. Superoxide dismutase activity was significantly decreased (7th day: P < 0.05; 14th day: P < 0.01) and malondialdehyde significantly increased (7th day: P < 0.05; 14th day: P < 0.01) after hyperoxia exposure. Protein and mRNA expression levels of β-catenin, Dvl-1, CTNNBL1 and cyclin D1 were significantly upregulated by hyperoxia exposure on 7th day (P < 0.01) and 14th day (P < 0.01). In hyperoxic conditions, Dvl-l downregulation and Dvl-l downregulation + MSAB treatment significantly increased the proliferation rates, decreased the apoptosis rates and improved the ability of cell migration. In hyperoxic conditions, Dvl-l downregulation could decrease the mRNA expression levels of GSK3β, β-catenin, CTNNBL1 and cyclin D1 and decrease the protein relative expression levels of GSK3β, p-GSK3β, β-catenin, CTNNBL1 and cyclin D1.

CONCLUSIONS

We confirmed the positive role of Dvl-1 and the Wnt/β-catenin signaling pathway in promoting BPD in hyperoxia conditions and provided a promising therapeutic target.

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.

Molecular mechanisms of cell death in bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) in neonates is the most common pulmonary disease that causes neonatal mortality, has complex pathogenesis, and lacks effective treatment. It is associated with chronic obstructive pulmonary disease, pulmonary hypertension, and right ventricular hypertrophy. The occurrence and development of BPD involve various factors, of which premature birth is the most crucial reason for BPD. Under the premise of abnormal lung structure and functional product, newborns are susceptible to damage to oxides, free radicals, hypoxia, infections and so on. The most influential is oxidative stress, which induces cell death in different ways when the oxidative stress balance in the body is disrupted. Increasing evidence has shown that programmed cell death (PCD), including apoptosis, necrosis, autophagy, and ferroptosis, plays a significant role in the molecular and biological mechanisms of BPD and the further development of the disease. Understanding the mode of PCD and its signaling pathways can provide new therapeutic approaches and targets for the clinical treatment of BPD. This review elucidates the mechanism of BPD, focusing on the multiple types of PCD in BPD and their molecular mechanisms, which are mainly based on experimental results obtained in rodents.

Impaired pulmonary function mediates inattention in young adults born extremely preterm

AIM

To test whether poor childhood pulmonary function explains the relationship between extremely preterm (EP) birth and attention-deficit/hyperactivity disorder (ADHD) symptoms in young adulthood.

METHODS

EPICure birth cohort participants include children born <26 weeks' gestation in the United Kingdom and Ireland in 1995 and their term-born classmates. Predictor was EP birth. Outcomes were inattention/hyperactivity subscale z-scores at 19 years. Forced expiratory volume (FEV1) z-scores in childhood and young adulthood were mediators. We used recursive path analysis to determine the direct effect of EP birth on inattention/hyperactivity and its indirect effect through pulmonary function.

RESULTS

Ninety EP and 47 term-born participants had pulmonary function testing at 11 and 19 years. Inattention z-scores were higher in the EP group (mean difference 0.55 [95% CI 0.11, 0.99]) but not hyperactivity. Compared to term-born peers, EP participants had lower FEV1 z-scores at 11 (mean difference-1.35 [95% CI -1.72, -0.98]) and 19 (mean difference-1.29 [95% CI -1.65, -0.92]). Path models revealed that childhood pulmonary function explained the relationship between EP birth and inattention.

CONCLUSIONS

Extremely preterm young adults have increased risk for inattention compared to term-born peers. Poor pulmonary function appears to underlie this risk. The mechanisms responsible remain unclear and warrant further study.

MSC-EXO and tempol ameliorate bronchopulmonary dysplasia in newborn rats by activating HIF-1α

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a major complication of premature infants and an important cause of morbidity and mortality. This study investigates the effect of the combination of mesenchymal stem cells-derived exosomes (MSC-EXO) and tempol on BPD and analyzes its mechanism.

METHODS

MSC-EXO was extracted by centrifugation and identified by transmission electron microscopy (TEM), nanoparticle tracking analysis, and western blot analysis (WB). Tidal volume (TV), minute ventilation (MV), peak inspiratory flow (PIF), and dynamic pulmonary compliance (Cdyn) of rats were measured by BuxCo pulmonary function experimental platform. Hematoxylin-eosin staining was performed to observe the lung morphology and radical alveolar count (RAC) and mean linear intercept (MLI) were assessed. Immunofluorescence (IF) was conducted to detect the expression of CD31 and α-SMA in pulmonary blood vessels. The kits were used to calculate malondialdehyde (MDA), superoxide dismutase (SOD), and total antioxidant capacity (TAOC) concentration in lung tissue. Enzyme linked immunosorbent assay was applied to detect the levels of IL-1β, IL-17, IL-6, and IFN-γ in bronchoalveolar lavage fluid. In addition, the expressions of HIF-1α, vascular endothelial growth factor (VEGF), p-PI3K, and p-AKT were analyzed by WB and IF.

RESULTS

We successfully extracted and identified MSC-EXO. In BPD rats, TV, MV, PIF, and Cdyn decreased, alveoli were simplified, and the number of interalveoli small vessels, blood vessel density decreased. Moreover, RAC, CD31, TAOC, and SOD decreased, and MLI, α-SMA, MDA, IL-1β, IL-17, IL-6, and IFN-γ increased, which was reversed by the combination of MSC-EXO and tempol treatment after combined treatment. In addition, the expression levels of HIF-1α, VEGF, p-PI3K, and p-AKT were increased after combined treatment.

CONCLUSIONS

Combined treatment could improve lung tissue injury, promote pulmonary vascular remodeling, restore lung function, and inhibit oxidative stress in BPD rats. These effects were achieved through activation of HIF-1α.

The Effect of Contingent Singing on Infants with Bronchopulmonary Dysplasia in the Neonatal Intensive Care Unit

A significant component of care for infants with bronchopulmonary dysplasia (BPD) is providing an optimal environment for supporting neurodevelopment and growth. Interventions that support the behavioral and physiologic stability of this population may play an important role in improving overall outcomes. Contingent singing is a music intervention that allows the caregiver to tailor certain musical elements, such as rhythm and tempo, to match behavioral and physiologic cues and support the infant in achieving optimal stabilization. A randomized crossover design was used to study the effect of contingent singing on the behavioral state and physiologic measures compared to standard care practices in the neonatal intensive care unit (NICU). Data were collected on a sample of 37 infants diagnosed with BPD. There were no significant differences in the physiologic measures or behavioral states of infants in the contingent singing sessions compared to control sessions. Parents and staff reported favorable views of music therapy in the NICU, and there were no adverse responses from infants during contingent singing. Further research is needed to determine the effectiveness of this intervention on the physiologic stability of infants with BPD.

The clinical value of lung ultrasound in premature infants with bronchopulmonary dysplasia

OBJECTIVE

This study aimed to explore the risk factors of bronchopulmonary dysplasia in premature infants and the clinical application value of lung ultrasound in the diagnosis of bronchopulmonary dysplasia.

METHODS

A total of 80 premature infants with a gestational age of <32 weeks or a birth weight of <1,500 g who were treated in our hospital from January to August 2021 were randomly divided into a bronchopulmonary dysplasia group (n=12) and a non-bronchopulmonary dysplasia group (n=62). The clinical data, lung ultrasound, and X-ray image characteristics of the two groups were compared.

RESULTS

Among the 74 preterm infants, 12 preterm infants were diagnosed with bronchopulmonary dysplasia, and 62 preterm infants were determined not to have bronchopulmonary dysplasia. There were significant differences in sex, severe asphyxia, invasive mechanical ventilation, premature membrane ruptures, and intrauterine infection between the two groups (p<0.05). Lung ultrasound showed abnormal pleural lines and alveolar-interstitial syndrome in all 12 patients with bronchopulmonary dysplasia and vesicle inflatable signs in 3 patients. Before clinical diagnosis, the accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of lung ultrasound in the diagnosis of bronchopulmonary dysplasia were 98.65, 100, 98.39, 92.31, and 100%, respectively. The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of X-rays in the diagnosis of bronchopulmonary dysplasia were 85.14, 75.00, 87.10, 52.94, and 94.74%, respectively.

CONCLUSION

The diagnostic efficiency of lung ultrasound for premature bronchopulmonary dysplasia is better than that of X-rays. The application of lung ultrasound can screen patients with bronchopulmonary dysplasia early for timely intervention.

SIRT3 improves alveolar epithelial cell damage caused by bronchopulmonary dysplasia through deacetylation of FOXO1

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a serious and long-term lung condition commonly observed in premature babies. Sirtuin 3 (SIRT3) has been reported to reduce pulmonary injury and pulmonary fibrosis.

OBJECTIVE

The present study investigated the specific role of SIRT3 in BPD by establishing hyperoxia-induced BPD rat and cell models. Hematoxylin and eosin staining was used to observe pathological changes in lung tissues.

MATERIALS AND METHODS

The expression levels of SIRT3 and forkhead box protein O1 (FOXO1), as well as its acetylation levels, were detected in hyperoxia-induced lung tissues and cells by Western blot analysis and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Levels of reactive oxygen species, superoxide dismutase, and malondialdehyde were assessed by using biochemical kits. Following SIRT3 overexpression, the levels of inflammatory cytokines were assessed by RT-qPCR. Apoptosis was determined by terminal deoxynucleotidyl transferase dUTP nickend labeling (TUNEL) and Western blot analysis. Upon FOXO1 knockout, cell inflammation, oxidative stress and apoptosis were evaluated again.

RESULTS

Compared to the control group, the SIRT3 and FOXO1 expression levels were decreased and the FOXO1 acetylation levels were increased in hyperoxia-induced lung tissues and cells. In addition, SIRT3 reduced hyperoxia-induced inflammation, oxidative stress, and apoptosis in A549 cells, and inhibited FOXO1 acetylation to activate FOXO1. However, FOXO1 knockdown reversed the effects of SIRT3 overexpression in hyperoxia-induced A549 cells.

CONCLUSION

SIRT3 relieved alveolar epithelial cell damage caused by BPD via deacetylation of FOXO1, suggesting that SIRT3 could be a therapeutic target in BPD.

Vascular and pulmonary effects of ibuprofen on neonatal lung development

BACKGROUND

Ibuprofen is a nonsteroidal anti-inflammatory drug that is commonly used to stimulate closure of a patent ductus arteriosus (PDA) in very premature infants and may lead to aberrant neonatal lung development and bronchopulmonary dysplasia (BPD).

METHODS

We investigated the effect of ibuprofen on angiogenesis in human umbilical cord vein endothelial cells (HUVECs) and the therapeutic potential of daily treatment with 50 mg/kg of ibuprofen injected subcutaneously in neonatal Wistar rat pups with severe hyperoxia-induced experimental BPD. Parameters investigated included growth, survival, lung histopathology and mRNA expression.

RESULTS

Ibuprofen inhibited angiogenesis in HUVECs, as shown by reduced tube formation, migration and cell proliferation via inhibition of the cell cycle S-phase and promotion of apoptosis. Treatment of newborn rat pups with ibuprofen reduced pulmonary vessel density in the developing lung, but also attenuated experimental BPD by reducing lung inflammation, alveolar enlargement, alveolar septum thickness and small arteriolar wall thickening.

CONCLUSIONS

In conclusion, ibuprofen has dual effects on lung development: adverse effects on angiogenesis and beneficial effects on alveolarization and inflammation. Therefore, extrapolation of the beneficial effects of ibuprofen to premature infants with BPD should be done with extreme caution.

Right ventricular myocardial performance index (Tei) in premature infants

OBJECTIVE

The objective of this study was to evaluate the right ventricular myocardial performance index) based on echocardiography in very low birth weight premature neonates, close to hospital discharge.

METHODS

This was a prospective cross-sectional study that included premature neonates with birth weight <1,500 g and gestational age <37 weeks at the Intermediate Neonatal Unit of Bonsucesso Federal Hospital from July 2005 to July 2006. The infants underwent two-dimensional color Doppler echocardiography, being the right ventricular myocardial performance index evaluated close to hospital discharge. We compared the neonatal and echocardiographic variables in neonates with and without bronchopulmonary dysplasia.

RESULTS

A total of 81 exams were analyzed. The mean birth (standard deviation) weight and gestational age were 1,140 (235) g and 30 (2.2) weeks, respectively. The incidence of bronchopulmonary dysplasia was 32%. The mean right ventricle myocardial performance index (standard deviation) of the sample was 0.13 (0.06). We found a significant difference in aortic diameter [non-bronchopulmonary dysplasia 0.79 (0.07) vs. bronchopulmonary dysplasia 0.87 (0.11) cm, p=0.003], left ventricle in diastole [non-bronchopulmonary dysplasia 1.4 (0.19) vs. bronchopulmonary dysplasia 1.59 (0.21) cm, p=0.0006], ventricular septal thickness [non-bronchopulmonary dysplasia 0.23 (0.03) vs. bronchopulmonary dysplasia 0.26 (0.05) cm, p=0.032], and "a" measurement [(= sum of the isovolumetric contraction time, ejection time, and isovolumetric relaxation time) when calculating the myocardial performance index (p=0.01)].

CONCLUSION

Higher "a" interval in neonates with bronchopulmonary dysplasia suggests right ventricle diastolic dysfunction. We conclude that the right ventricle myocardial performance index is an important indicator both of ventricular function and for serial follow-up testing of very low birth weight premature neonates, especially those with bronchopulmonary dysplasia.

Neutrophil extracellular traps promote bronchopulmonary dysplasia-like injury in neonatal mice via the WNT/β-catenin pathway

Background

Bronchopulmonary dysplasia (BPD) is one of the most common and severe chronic diseases in preterm infants. Premature infants are susceptible to BPD due to immature lungs and adverse perinatal episodes of infection, hyperoxia, and mechanical ventilation.

Methods

Neutrophils are the first line of host defence, and the release of neutrophil extracellular traps (NETs) is an important strategy to immobilize and kill invading microorganisms. This study examined whether NETs were associated with BPD in preterm infants and contributed to hyperoxia-induced lung injury in neonatal mice via the WNT/β-catenin pathway.

Results

In this study, we found that preterm infants with BPD had higher levels of NETs in their tracheal aspirates than those without BPD. Neonatal mice treated with NETs after birth exhibited BPD-like changes in their lungs. Furthermore, the levels of Aquaporin 5 (AQP5) and surfactant-associated protein C (SPC), which represent alveolar differentiation and development, were significantly lower than those in the controls. The WNT/β-catenin pathway is one of the most well-known signalling pathways involved in lung growth. We found that the expression of the target genes c-MYC, cyclin D, and vascular endothelial growth factor (VEGF) and the important proteins WNT3a and β-catenin significantly decreased. Moreover, heparin, which is a NET inhibitor, attenuated changes in gene and protein expression, thereby attenuating BPD-like changes.

Discussion

This finding indicates that NETs are associated with BPD and can induce BPD-like changes in neonatal mice via the WNT/β-catenin pathway.

Pathogenesis of bronchopulmonary dysplasia in preterm neonates revealed by an RNA sequencing interaction network analysis

BACKGROUND

The chronic lung condition known as bronchopulmonary dysplasia (BPD), which primarily affects newborns, especially preterm neonates, is brought on by prolonged oxygen consumption and mechanical ventilation. This case-control study sought to investigate the pathogenesis of BPD in preterm neonates by RNA sequencing (RNA-seq).

METHODS

First, RNA-seq samples were collected from 3 BPD and 3 healthy preterm neonates. Based on the sequencing data and microarray data sets, MERGE.57185.1, the key long non-coding RNA (lncRNA), was identified from the differentially expressed lncRNAs and the key module by a weighted gene co-expression network analysis (WGCNA), a Venn diagram, and an expression analysis. Next, the differentially expressed messenger RNAs (mRNAs) and microRNAs (miRNAs) that were strongly correlated to MERGE.57185.1 were identified in the protein-protein interaction networks and underwent a functional enrichment analysis and Spearman correlation analysis. Finally, the mRNA [i.e., eukaryotic translation initiation factor 5A (EIF5A)] and miRNA (i.e., hsa-miR-6833-5p) with the strongest correlations to MERGE.57185.1 were identified as the downstream targets.

RESULTS

Among the 32 genes in the dark-red module and the 158 differentially expressed lncRNAs, 21 overlapping genes were identified. In the gene expression analysis, MERGE.57185.1 (an oncogene) was identified as the key lncRNA in BPD. The results of the multiple bioinformatics analysis showed that the mRNA and the miRNA with the strongest correlations to MERGE.57185.1 were hsa-miR-6833-5p (a suppressor gene) and EIF5A (an oncogene), respectively. Hsa-miR-6833-5p was lowly expressed in the BPD group, while EIF5A was highly expressed in the BPD group.

CONCLUSIONS

This study identified 1 key upregulated lncRNA (i.e., MERGE.57185.1) in preterm neonatal BPD, and revealed the MERGE.57185.1/hsa-miR-6833-5p/EIF5A mechanism in preterm neonatal BPD from the lncRNA-miRNA-mRNA network. This key lncRNA gene could serve as a promising diagnostic biomarker for prenatal examinations.

Care practices and short-term clinical outcomes of very low birth weight infants in Yangtze River Delta in China

BACKGROUND

Intensive care is of great significance for very low birth weight infants (VLBWI). The Yangtze River Delta is the most ecomonically developed area in China. However, there are few data on the care practices and survival of VLBWI in this region.

OBJECTIVES

To investigate the prevalence, care practices and motality of VLBWI in Yangtze River Delta in China.

METHODS

A multi-center retrospective investigation study was conducted at five tertiary hospitals within the Yangtze River Delta in China from January to December 2017. Clinical data included the general characteristics of the infants and the mothers, clinical prognosis, care practices in NICUs was collected by trained research members.

RESULTS

During the study period, 1059 VLBWIs were included. Infants with birth weight < 750 g, 750-1000 g, 1000-1250 g and 1250-1500 g accounted for 2.3, 14.9, 34.8 and 47.8%, respectively. Premature rupture of membranes (17.8%) was the main cause of premature delivery. The catheterization rates of umbilical vein catheterization (UVC) and peripherally inserted central catheter (PICC) were 25.0 and 64.4%, respectively. The duration of parenteral nutrition was 27.0 ± 19.5 d, the meantime of feeding tube indwelling was 36.2 ± 24.2 d. The corrected gestational age of the infants who reached full oral feeding was 35.8 ± 2.7 weeks. The breast feeding rate in the investigated infants was 61.9%. The mortality rate of preterm infants was 3.4%. The incidence of main complications BPD, PDA, ROP, NEC and sepsis were 24.9, 29.9, 21.7, 9.4 and 13.3% respectively.

CONCLUSIONS

Maternal and infant care practices need to be improved in the very preterm births. This study provides a baseline for the improvement in the further study.

The Outcome- or Cost-Effectiveness Analysis of LUS-Based Care or CXR-Based Care of Neonatal Lung Diseases: The Clinical Practice Evidence from a Level Ⅲ NICU in China

OBJECTIVE

To compare the effect of managing neonatal lung disease with lung ultrasound (LUS) or chest X-ray (CXR) monitoring on health outcomes and cost-effectiveness.

METHODS

The data obtained from the NICU of the Beijing Chaoyang District Maternal and Child Healthcare Hospital were used as the study group, as LUS has completely replaced CXR in managing newborn lung disease in the hospital for the past 5 years. The primary outcomes of this study were the misdiagnosis rate of respiratory distress syndrome (RDS), the using status of mechanical ventilation, the incidence rate of bronchopulmonary dysplasia (BPD) and the survival rate in hospitalized infants. The secondary outcomes included the use pulmonary surfactant (PS), and the mortality rate of severe diseases (such as pneumothorax, pulmonary hemorrhage and RDS, etc.).

RESULTS

Managing neonatal lung disease with LUS monitoring may enable the following effects: The frequency of ventilator use reducing by 40.2%; the duration of mechanical ventilation reducing by 67.5%; and the frequency of ventilator weaning failure being totally avoided. A misdiagnosis rate of 30% for RDS was also avoided. The dosage of PS was significantly reduced by 50% to 75%. No BPD occurred in the LUS-based care group for 5 years. The fatality rates of RDS, pneumothorax and pulmonary hemorrhage decreased by 100%. The poor prognosis rate of VLBW infants decreased by 85%, and the total mortality rate of hospitalized infants decreased by 90%. Therefore, the cost of LUS-based care was inevitably saved.

CONCLUSIONS

Diagnosing and managing neonatal lung diseases with LUS monitoring have significant benefits, and this technology should be widely promoted and applied around the world.

Risk factors and machine learning prediction models for bronchopulmonary dysplasia severity in the Chinese population

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a common chronic lung disease in extremely preterm neonates. The outcome and clinical burden vary dramatically according to severity. Although some prediction tools for BPD exist, they seldom pay attention to disease severity and are based on populations in developed countries. This study aimed to develop machine learning prediction models for BPD severity based on selected clinical factors in a Chinese population.

METHODS

In this retrospective, single-center study, we included patients with a gestational age < 32 weeks who were diagnosed with BPD in our neonatal intensive care unit from 2016 to 2020. We collected their clinical information during the maternal, birth and early postnatal periods. Risk factors were selected through univariable and ordinal logistic regression analyses. Prediction models based on logistic regression (LR), gradient boosting decision tree, XGBoost (XGB) and random forest (RF) models were implemented and assessed by the area under the receiver operating characteristic curve (AUC).

RESULTS

We ultimately included 471 patients (279 mild, 147 moderate, and 45 severe cases). On ordinal logistic regression, gestational diabetes mellitus, initial fraction of inspiration O₂ value, invasive ventilation, acidosis, hypochloremia, C-reactive protein level, patent ductus arteriosus and Gram-negative respiratory culture were independent risk factors for BPD severity. All the XGB, LR and RF models (AUC = 0.85, 0.86 and 0.84, respectively) all had good performance.

CONCLUSIONS

We found risk factors for BPD severity in our population and developed machine learning models based on them. The models have good performance and can be used to aid in predicting BPD severity in the Chinese population.

Risk Factors Affecting Development and Persistence of Preschool Wheezing: Consensus Document of the Emilia-Romagna Asthma (ERA) Study Group

Wheezing at preschool age (i.e., before the age of six) is common, occurring in about 30% of children before the age of three. In terms of health care burden, preschool children with wheeze show double the rate of access to the emergency department and five times the rate of hospital admissions compared with school-age asthmatics. The consensus document aims to analyse the underlying mechanisms involved in the pathogenesis of preschool wheezing and define the risk factors (i.e., allergy, atopy, infection, bronchiolitis, genetics, indoor and outdoor pollution, tobacco smoke exposure, obesity, prematurity) and the protective factors (i.e., probiotics, breastfeeding, vitamin D, influenza vaccination, non-specific immunomodulators) associated with the development of the disease in the young child. A multidisciplinary panel of experts from the Emilia-Romagna Region, Italy, addressed twelve key questions regarding managing preschool wheezing. Clinical questions have been formulated by the expert panel using the PICO format (Patients, Intervention, Comparison, Outcomes). Systematic reviews have been conducted on PubMed to answer these specific questions and formulate recommendations. The GRADE approach has been used for each selected paper to assess the quality of the evidence and the degree of recommendations. Based on a panel of experts and extensive updated literature, this consensus document provides insight into the pathogenesis, risk and protective factors associated with the development and persistence of preschool wheezing. Undoubtedly, more research is needed to improve our understanding of the disease and confirm the associations between certain factors and the risk of wheezing in early life. In addition, preventive strategies must be promoted to avoid children's exposure to risk factors that may permanently affect respiratory health.

Dead space washout by intentional leakage flow during conventional ventilation of premature infants-an experimental study

OBJECTIVE

Invasive mechanical ventilation poses a strong risk factor for the development of chronic lung disease in preterm infants. A reduction of the dead space as part of the total breathing volume would reduce the ventilation effort and thereby lower the risk of ventilator-induced lung injuries. In this experimental study, we compared the efficacy of mechanical dead space washout via uncontrolled and controlled leakage flow in their ability to eliminate CO₂ during conventional ventilation in preterm infants.

METHODS

Three frequently used neonatal ventilators, operating under standard conventional ventilating parameters, were individually connected to a test lung. To maintain a constant physiological end-expiratory pCO₂ level during ventilation, the test lung was continuously flooded with CO₂ . A side port in the area of the connector between the endotracheal tube and the flow sensor allowed breathing gas to escape passively or in a second experimental setup, regulated by a pump. Measurements of end-expiratory pCO₂ were taken in both experiments and compared to end-expiratory pCO₂ levels of ventilation without active dead space leakage.

RESULTS

Following dead space washout, a significant reduction of end-expiratory pCO₂ was attained. Under conditions of uncontrolled leakage, the mean decrease was 14.1% while controlled leakage saw a mean reduction of 16.1%.

CONCLUSION

Washout of dead space by way of leakage flow is an effective method to reduce end-expiratory pCO₂ . Both controlled and uncontrolled leakage provide comparable results, but precise regulation of leakage allows for a more stable ventilation by preventing uncontrolled loss of tidal volume during inspiration.

Bronchopulmonary dysplasia and wnt pathway-associated single nucleotide polymorphisms

AIM

Genetic variants contribute to the pathogenesis of bronchopulmonary dysplasia (BPD). The aim of this study is to evaluate the association of 45 SNPs with BPD susceptibility in a Turkish premature infant cohort.

METHODS

Infants with gestational age &lt;32 weeks were included. Patients were divided into BPD or no-BPD groups according to oxygen need at 28 days of life, and stratified according to the severity of BPD. We genotyped 45 SNPs, previously identified as BPD risk factors, in 192 infants.

RESULTS

A total of eight SNPs were associated with BPD risk at allele level, two of which (rs4883955 on KLF12 and rs9953270 on CHST9) were also associated at the genotype level. Functional relationship maps suggested an interaction between five of these genes, converging on WNT5A, a member of the WNT pathway known to be implicated in BPD pathogenesis. Dysfunctional CHST9 and KLF12 variants may contribute to BPD pathogenesis through an interaction with WNT5A.

CONCLUSIONS

We suggest investigating the role of SNPs on different genes which are in relation with the Wnt pathway in BPD pathogenesis. We identified eight SNPs as risk factors for BPD in this study. In-silico functional maps show an interaction of the genes harboring these SNPs with the WNT pathway, supporting its role in BPD pathogenesis.

TRIAL REGISTRATION

NCT03467828.

IMPACT

It is known that genetic factors may contribute to the development of BPD in preterm infants. Further studies are required to identify specific genes that play a role in the BPD pathway to evaluate them as a target for therapeutic interventions. Our study shows an association of BPD predisposition with certain polymorphisms on MBL2, NFKBIA, CEP170, MAGI2, and VEGFA genes at allele level and polymorphisms on CHST9 and KLF12 genes at both allele and genotype level. In-silico functional mapping shows a functional relationship of these five genes with WNT5A, suggesting that Wnt pathway disruption may play a role in BPD pathogenesis.

Nutrition of Infants with Bronchopulmonary Dysplasia before and after Discharge from the Neonatal Intensive Care Unit

Bronchopulmonary dysplasia (BPD) represents a severe sequela in neonates born very prematurely. The provision of adequate nutritional support in this high-risk population is challenging. The development of the lungs and physical growth are closely linked together in infants with BPD. Growth deficiency has been associated with pulmonary dysfunction, whereas improvement in respiratory status results in growth acceleration. Currently, there is not enough data regarding optimal nutritional strategies in this population. Nutrition in these infants should provide sufficient calories and nutrients to establish growth, avoid growth retardation and assist alveolarization of the lungs. Meticulous follow-up is mandatory during and after discharge from the Neonatal Intensive care Unit (NICU) to minimize growth retardation and improve lung function. Despite the significant literature supporting the contribution of growth and nutrition in the avoidance of BPD, there is limited research regarding interventions and management of infants with established BPD. Our aim was to review clinical strategies applied in everyday clinical practice and identify debates on the nutritional approach of newborns with BPD. Well-organized interventions and clinical trials regarding the somatic development and nutrition of infants with BPD are warranted.