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

Proline betaine facilitates angiogenesis in bronchopulmonary dysplasia

BACKGROUND

Bronchopulmonary dysplasia (BPD) is prevalent and severe diseases in preterm infants, characterized by abnormal lung development. This study aims to investigate the therapeutic potential of proline betaine, a natural alkaloid recognized for its vasculo-protective and anti-inflammatory properties, in BPD model.

METHODS

Network pharmacology was utilized to predict the targets of proline betaine and BPD-related genes (BPD-RGs). In vitro, HUVECs were treated with proline betaine to evaluate its effects on proliferation and angiogenesis. In vivo, a hyperoxia-induced BPD rat model (85 % oxygen, first day to 14th day) was used to evaluate the effects of proline betaine on pulmonary injury, angiogenesis and fibrosis.

RESULTS

We identified a total of 100 proline-betaine targets and 825 BPD-RGs, with 20 shared targets between them. These shared targets modulated inflammation, immune response, hypoxia, and vascular homeostasis, especially the vascular phenotype. In vitro, proline betaine significantly enhanced the activity, number of tubes, and capillary length of HUVECs. The pro-angiogenic effect of proline betaine on HUVECs was dose-dependent. The hyperoxia-induced BPD rat model corroborated these findings. In vivo, proline betaine increased the radial alveolar count and reduced the mean linear intercept and collagen content in the lung. Mechanistically, proline betaine upregulated VEGF and VEGFR2 expression as well as MEK/ERK pathway activity. Notably, blocking the VEGFR2 and MEK/ERK pathways made proline betaine less effective as a medicine.

CONCLUSION

Proline betaine enhances angiogenesis and mitigates pulmonary injury through the MEK/ERK pathway. These findings suggest that proline betaine could serve as a novel therapeutic strategy for managing BPD in neonates.

Gender-specific effects of prenatal polystyrene nanoparticle exposure on offspring lung development

Nanoplastics are widely present in the environment. Exposure to environmental pollutants during pregnancy can have adverse effects on fetal development and health. Establishing a link between nanoplastics and Bronchopulmonary Dysplasia (BPD) requires further investigation. In this study, we examined the impact of prenatal exposure to 80 nm polystyrene nanoparticles (PS-NPs) on offspring lung development, taking into account potential gender-specific effects. Pregnant female mice were exposed to PS-NPs through oropharyngeal aspiration, and critical data on lung development were collected at postnatal days 1, 7, and 21. We found that exposure to PS-NPs reduced birth weight in female offspring and significantly increased lung weight in both male and female offspring by PND 21. Maternal exposure led to a reduction in alveolar numbers across offspring, with distinct underlying mechanisms observed between sexes. In female offspring, the reduction in alveolar numbers was linked to disrupted surfactant protein expression, significant inflammation, and increased apoptosis and fibrosis. In male offspring, impaired angiogenesis was the primary factor contributing to the increased risk of BPD. The impact on alveolar development was substantial in both genders. This study underscores the gender-specific impacts of prenatal nanoplastic exposure on lung development and offers new evidence and direction for future research on the cross-generational respiratory toxicity of PS-NPs.

A rat model establishment of bronchopulmonary dysplasia-related lung & brain injury within 28 days after birth

PURPOSE

Lung injury associated with bronchopulmonary dysplasia (BPD) and its related neurodevelopmental disorders have garnered increasing attention in the context of premature infants. Establishing a reliable animal model is essential for delving into the underlying mechanisms of these conditions.

METHODS

Newborn rats were randomly assigned to two groups: the hyperoxia-induced BPD group and the normoxia (NO) group. For the BPD group, they were nurtured in a hyperoxic environment with a high oxygen inspired fraction (0.85) from birth until day 14 within 28 days postnatally. In contrast, the NO group consisted of newborn rats that were nurtured in a normoxic environment with a standard oxygen inspired fraction (0.21) for 28 days postnatally. Various pathological sections of both lung and brain tissues were examined. TUNEL staining, immunofluorescence assays, and functional tests were performed, and the results were meticulously analyzed to assess the impact of hyperoxia environments on the developing organs.

RESULTS

In the newborn rats of the BPD group, a significant reduction in alveolar number coupled with enlargement was observed, alongside severe fibrosis, collagen deposition, and constriction of bronchi and vascular lumens. This was accompanied by an accumulation of inflammatory cells and a marked deterioration in lung function compared to the NO group (P < 0.05). Additionally, a decrease in neuronal count, an increase in neuronal apoptosis, proliferation of neuroglia cells, and demyelination were noted, and poorer performance in the Morris water maze test within the BPD group (P < 0.05).

CONCLUSION

The BPD-rats model was established successfully. Lung injury in the BPD group evident across the bronchi to the alveoli and pulmonary vessels, which was associated with deteriorated lung function at postnatal day 14. Concurrently, brain injury extended from the cerebral cortex to the hippocampus, which was associated with impaired performance in orientation navigation and spatial probe tests at postnatal day 28.

Knockdown of the long noncoding RNA VSIG2-1:1 promotes the angiogenic ability of human pulmonary microvascular endothelial cells by activating the VEGF/PI3K/AKT pathway

BACKGROUND

Abnormal pulmonary vascular development poses significant clinical challenges for infants with bronchopulmonary dysplasia (BPD). Although numerous factors have been suggested to control the development of pulmonary blood vessels, the mechanisms underlying the role of long noncoding RNAs (lncRNAs) in this process remain unclear.

METHODS

A lncRNA array was used to measure the differential expression of lncRNAs in premature infants with and without BPD. The expression of lncRNA-VSIG2-1:1 in patients with BPD and hyperoxia-induced human pulmonary microvascular endothelial cells (HPMECs) was assessed using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Fluorescence in situ hybridization (FISH) assay was performed to detect the subcellular localization of lncRNA-VSIG2-1:1. Pulmonary microvascular endothelial cells were stably transfected with adenoviral vectors to silence or overexpress lncRNA-VSIG2-1:1. The effects of lncRNA-VSIG2-1:1 on the proliferation, migration, and tube formation abilities of HPMECs subjected to hyperoxia were examined by performing Cell Counting Kit-8 (CCK-8), cell migration, and tubule formation assays. RNA sequencing (RNA-seq) was performed to determine the correlation between lncRNA-VSIG2-1:1 and phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT). The protein levels of vascular endothelial growth factor (VEGF), p-PI3K, PI3K, p-AKT, and AKT were determined using western blotting.

RESULTS

The expression of lncRNA-VSIG2-1:1 was upregulated in patients with BPD and hyperoxia-treated HPMECs. Inhibiting lncRNA-VSIG2-1:1 expression promoted the proliferation, migration, and tube-formation abilities of HPMECs, while significantly increasing VEGF, p-PI3K, and p-AKT levels.

CONCLUSION

Our findings reveal that the suppression of lncRNA-VSIG2-1:1 expression stimulates angiogenesis in vitro by inducing the initiation of the VEGF/PI3K/AKT signaling pathway. This observation may aid the development of novel therapeutic targets for treating BPD.

The association between VEGF genetic variations and the risk of bronchopulmonary dysplasia in premature infants: a meta-analysis and systematic review

Objective

Previous studies on the link between VEGF gene polymorphisms and bronchopulmonary dysplasia (BPD) have yielded inconsistent results. This meta-analysis sought to clarify the relationship between genetic variations in the VEGF gene and the risk of BPD.

Methods

Data were collected from multiple databases, including PubMed, Scopus, EMBASE, and CNKI, up to January 5, 2024.

Results

Nineteen case-control studies were analyzed, featuring 1,051 BPD cases and 1,726 healthy neonates. The analysis included four studies on the -460T/C polymorphism (312 cases, 536 controls), four on the -2578C/A polymorphism (155 cases, 279 controls), six on the +405G/C polymorphism (329 cases, 385 controls), and five on the +936C/T polymorphism (225 cases, 526 controls). The meta-analysis suggests that the -460T/C polymorphism may protect against BPD (C vs. T: OR = 0.715, 95% CI 0.543-0.941, p = 0.017; CC vs. TT: OR = 0.478, 95% CI 0.233-0.983, p = 0.045; CC vs. CT + TT: OR = 0.435, 95% CI 0.248-0.764, p = 0.004). No significant associations were found between the -2578C/A, +405G/C, and +936C/T polymorphisms and BPD susceptibility.

Conclusions

This meta-analysis indicates that the C allele of the -460T/C polymorphism may offer protection against BPD. No significant associations were observed for the -2578C/A, +405G/C, and +936C/T polymorphisms.

Reinitiating lung development: a novel approach in the management of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the predominant chronic lung disease in preterm infants, linked with various adverse long-term outcomes. Multiple prenatal and postnatal risk factors can impede lung development, leading to BPD. Current management of BPD relies heavily on pharmacotherapies and alterations in ventilatory strategies. However, these interventions only mitigate BPD symptoms without addressing underlying alveolar, vascular, structural, and functional deficiencies. Given the retarded lung development in infants with BPD and the limitations of existing modalities, new therapeutic approaches are imperative. The induced differentiation of stem/progenitor cells and the spatiotemporal expression patterns of growth factors associated with lung developmental processes are critical for lung development reactivation in BPD, which focuses on stimulating pulmonary vasculogenesis and alveolarization. This review summarizes the process of lung development and offers a comprehensive overview of advancements in therapies designed to reinitiate lung development in BPD. Furthermore, we assessed the potential of these therapies for maintaining lung homeostasis and effectively restoring pulmonary structure and function through stem/progenitor cells and growth factors, which have been widely researched.

Lower peripheral blood CD4+ lymphocyte ratio is associated with severe bronchopulmonary dysplasia

OBJECTIVE

To elucidate the characteristics of lymphocyte subsets in bronchopulmonary dysplasia (BPD) diagnosis following Jensen's criterion to understand the spectrum of lymphocytes in different degrees of BPD.

STUDY DESIGN

This single-center retrospective cohort study included 120 neonates admitted to the neonatal intensive care unit between 1 July 2014 and 30 June 2021, who had undergone peripheral blood lymphocyte subpopulation detection.

RESULTS

Thirty-one neonates were included in the control group, whereas 33 infants with BPD were included in the case group. In addition, we selected 56 infants with a gestational age (GA) <37 weeks without BPD who were receiving oxygen therapy. Among the three groups, the B cell and NK cell frequencies were significantly higher and the frequencies of T cells and CD4+ cells were significantly lower in the BPD group. In newborns without BPD, the distribution of T lymphocyte subsets was similar at different GAs. Comparing different degrees of BPD, the patients in the grades 2-3 BPD group had significantly lower percentages of T lymphocytes and CD4+ T cells than those in the other groups. Remarkably, the frequencies of NK cells were significantly higher in patients with grades 2-3 BPD, and the Treg cells slightly increased with BPD severity, although the differences were not significant.

CONCLUSION

Healthy neonates had similar ratios of lymphocyte subsets among different GAs; although as the GAs increased, the percentage of lymphocytes increased slightly. Severe BPD was associated with lower CD4+ T cells and higher NK cells. However, whether such changes were the cause or the consequence of BPD has not been determined.

Temporal Dynamics of Oxidative Stress and Inflammation in Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is the most common lung complication of prematurity. Despite extensive research, our understanding of its pathophysiology remains limited, as reflected by the stable prevalence of BPD. Prematurity is the primary risk factor for BPD, with oxidative stress (OS) and inflammation playing significant roles and being closely linked to premature birth. Understanding the interplay and temporal relationship between OS and inflammation is crucial for developing new treatments for BPD. Animal studies suggest that OS and inflammation can exacerbate each other. Clinical trials focusing solely on antioxidants or anti-inflammatory therapies have been unsuccessful. In contrast, vitamin A and caffeine, with antioxidant and anti-inflammatory properties, have shown some efficacy, reducing BPD by about 10%. However, more than one-third of very preterm infants still suffer from BPD. New therapeutic agents are needed. A novel tripeptide, N-acetyl-lysyltyrosylcysteine amide (KYC), is a reversible myeloperoxidase inhibitor and a systems pharmacology agent. It reduces BPD severity by inhibiting MPO, enhancing antioxidative proteins, and alleviating endoplasmic reticulum stress and cellular senescence in a hyperoxia rat model. KYC represents a promising new approach to BPD treatment.

Caffeine: The Story beyond Oxygen-Induced Lung and Brain Injury in Neonatal Animal Models-A Narrative Review

Caffeine is one of the most commonly used drugs in intensive care to stimulate the respiratory control mechanisms of very preterm infants. Respiratory instability, due to the degree of immaturity at birth, results in apnea of prematurity (AOP), hyperoxic, hypoxic, and intermittent hypoxic episodes. Oxidative stress cannot be avoided as a direct reaction and leads to neurological developmental deficits and even a higher prevalence of respiratory diseases in the further development of premature infants. Due to the proven antioxidant effect of caffeine in early use, largely protective effects on clinical outcomes can be observed. This is also impressively observed in experimental studies of caffeine application in oxidative stress-adapted rodent models of damage to the developing brain and lungs. However, caffeine shows undesirable effects outside these oxygen toxicity injury models. This review shows the effects of caffeine in hyperoxic, hypoxic/hypoxic-ischemic, and intermittent hypoxic rodent injury models, but also the negative effects on the rodent organism when caffeine is administered without exogenous oxidative stress. The narrative analysis of caffeine benefits in cerebral and pulmonary preterm infant models supports protective caffeine use but should be given critical consideration when considering caffeine treatment beyond the recommended corrected gestational age.

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.

The Influence of Neurotrophins on the Brain-Lung Axis: Conception, Pregnancy, and Neonatal Period

Neurotrophins (NTs) are four small proteins produced by both neuronal and non-neuronal cells; they include nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4). NTs can exert their action through both genomic and non-genomic mechanisms by interacting with specific receptors. Initial studies on NTs have identified them only as functional molecules of the nervous system. However, recent research have shown that some tissues and organs (such as the lungs, skin, and skeletal and smooth muscle) as well as some structural cells can secrete and respond to NTs. In addition, NTs perform several roles in normal and pathological conditions at different anatomical sites, in both fetal and postnatal life. During pregnancy, NTs are produced by the mother, placenta, and fetus. They play a pivotal role in the pre-implantation process and in placental and embryonic development; they are also involved in the development of the brain and respiratory system. In the postnatal period, it appears that NTs are associated with some diseases, such as sudden infant death syndrome (SIDS), asthma, congenital central hypoventilation syndrome (CCHS), and bronchopulmonary dysplasia (BPD).

IRF4 affects the protective effect of regulatory T cells on the pulmonary vasculature of a bronchopulmonary dysplasia mouse model by regulating FOXP3

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a common chronic lung disease in preterm infants, characterised by compromised alveolar development and pulmonary vascular abnormalities. Emerging evidence suggests that regulatory T cells (Tregs) may confer protective effects on the vasculature. Knockdown of their transcription factor, interferon regulatory factor 4 (IRF4), has been shown to promote vascular endothelial hyperplasia. However, the involvement of Tregs and IRF4 in the BPD pathogenesis remains unclear. This study aimed to investigate the regulation of Tregs by IRF4 and elucidate its potential role in pulmonary vasculature development in a BPD mouse model.

METHODS

The BPD model was established using 85% hyperoxia exposure, with air exposure as the normal control. Lung tissues were collected after 7 or 14 days of air or hyperoxia exposure, respectively. Haematoxylin-eosin staining was performed to assess lung tissue pathology. Immunohistochemistry was used to measure platelet endothelial cell adhesion molecule-1 (PECAM-1) level, flow cytometry to quantify Treg numbers, and Western blot to assess vascular endothelial growth factor (VEGFA), angiopoietin-1 (Ang-1), forkhead box protein P3 (FOXP3), and IRF4 protein levels. We also examined the co-expression of IRF4 and FOXP3 proteins using immunoprecipitation and immunofluorescence double staining. Furthermore, we employed CRISPR/Cas9 technology to knock down the IRF4 gene and observed changes in the aforementioned indicators to validate its effect on pulmonary vasculature development in mice.

RESULTS

Elevated IRF4 levels in BPD model mice led to FOXP3 downregulation, reduced Treg numbers, and impaired pulmonary vascular development. Knockdown of IRF4 resulted in improved pulmonary vascular development and upregulated FOXP3 level.

CONCLUSION

IRF4 may affect the protective role of Tregs in the proliferation of pulmonary vascular endothelial cells and pulmonary vascular development in BPD model mice by inhibiting the FOXP3 level.

Oxygen and mechanical stretch in the developing lung: risk factors for neonatal and pediatric lung disease

Chronic airway diseases, such as wheezing and asthma, remain significant sources of morbidity and mortality in the pediatric population. This is especially true for preterm infants who are impacted both by immature pulmonary development as well as disproportionate exposure to perinatal insults that may increase the risk of developing airway disease. Chronic pediatric airway disease is characterized by alterations in airway structure (remodeling) and function (increased airway hyperresponsiveness), similar to adult asthma. One of the most common perinatal risk factors for development of airway disease is respiratory support in the form of supplemental oxygen, mechanical ventilation, and/or CPAP. While clinical practice currently seeks to minimize oxygen exposure to decrease the risk of bronchopulmonary dysplasia (BPD), there is mounting evidence that lower levels of oxygen may carry risk for development of chronic airway, rather than alveolar disease. In addition, stretch exposure due to mechanical ventilation or CPAP may also play a role in development of chronic airway disease. Here, we summarize the current knowledge of the impact of perinatal oxygen and mechanical respiratory support on the development of chronic pediatric lung disease, with particular focus on pediatric airway disease. We further highlight mechanisms that could be explored as potential targets for novel therapies in the pediatric population.

Genetic Polymorphisms of Vascular Endothelial Growth Factor in Neonatal Pathologies: A Systematic Search and Narrative Synthesis of the Literature

(1) Background: Vascular endothelial growth factor (VEGF) is essential in vasculo- and angiogenesis due to its role in endothelial cell proliferation and migration. As a vascular proliferative factor, VEGF is one of the hallmarks of cancer and, in adult populations, the relationship between genetic polymorphism and neoplasm was widely investigated. For the neonatal population, only a few studies attempted to uncover the link between the genetic polymorphism of VEGF and neonatal pathology, especially related to late-onset complications. Our objective is to evaluate the literature surrounding VEGF genetic polymorphisms and the morbidity of the neonatal period. (2) Methods: A systematic search was initially conducted in December 2022. The PubMed platform was used to explore MEDLINE (1946 to 2022) and PubMed Central (2000 to 2022) by applying the search string ((VEGF polymorphism*) and newborn*). (3) Results: The PubMed search yielded 62 documents. A narrative synthesis of the findings was undertaken considering our predetermined subheadings (infants with low birth weight or preterm birth, heart pathologies, lung diseases, eye conditions, cerebral pathologies, and digestive pathologies). (4) Conclusion: The VEGF polymorphisms seem to be associated with neonatal pathology. The involvement of VEGF and VEGF polymorphism has been demonstrated for retinopathy of prematurity.