The expression of VEGF and its receptors in the human ductus arteriosus

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.

The molecular mechanisms of oxygen-sensing in human ductus arteriosus smooth muscle cells: A comprehensive transcriptome profile reveals a central role for mitochondria

The ductus arteriosus (DA) connects the fetal pulmonary artery and aorta, diverting placentally oxygenated blood from the developing lungs to the systemic circulation. The DA constricts in response to increases in oxygen (O2) with the first breaths, resulting in functional DA closure, with anatomic closure occurring within the first days of life. Failure of DA closure results in persistent patent ductus arteriosus (PDA), a common complication of extreme preterm birth. The DA's response to O2, though modulated by the endothelium, is intrinsic to the DA smooth muscle cells (DASMC). DA constriction is mediated by mitochondrial-derived reactive oxygen species, which increase in proportion to arterial partial pressure of oxygen (PaO2). The resulting redox changes inhibit voltage-gated potassium channels (Kv) leading to cell depolarization, calcium influx and DASMC constriction. To date, there has not been an unbiased assessment of the human DA O2-sensors using transcriptomics, nor are there known molecular mechanisms which characterize DA closure. DASMCs were isolated from DAs obtained from 10 term infants at the time of congenital heart surgery. Cells were purified by flow cytometry, negatively sorting using CD90 and CD31 to eliminate fibroblasts or endothelial cells, respectively. The purity of the DASMC population was confirmed by positive staining for α-smooth muscle actin, smoothelin B and caldesmon. Cells were grown for 96 h in hypoxia (2.5% O2) or normoxia (19% O2) and confocal imaging with Cal-520 was used to determine oxygen responsiveness. An oxygen-induced increase in intracellular calcium of 18.1% ± 4.4% and SMC constriction (-27% ± 1.5% shortening) occurred in all cell lines within five minutes. RNA sequencing of the cells grown in hypoxia and normoxia revealed significant regulation of 1344 genes (corrected p < 0.05). We examined these genes using Gene Ontology (GO). This unbiased assessment of altered gene expression indicated significant enrichment of the following GOterms: mitochondria, cellular respiration and transcription. The top regulated biologic process was generation of precursor metabolites and energy. The top regulated cellular component was mitochondrial matrix. The top regulated molecular function was transcription coactivator activity. Multiple members of the NADH-ubiquinone oxidoreductase (NDUF) family are upregulated in human DASMC (hDASMC) following normoxia. Several of our differentially regulated transcripts are encoded by genes that have been associated with genetic syndromes that have an increased incidence of PDA (Crebb binding protein and Histone Acetyltransferase P300). This first examination of the effects of O2 on human DA transcriptomics supports a putative role for mitochondria as oxygen sensors.

Vascular Endothelial Growth Factor: A Translational View in Oral Non-Communicable Diseases

Vascular endothelial growth factors (VEGFs) are vital regulators of angiogenesis that are expressed in response to soluble mediators, such as cytokines and growth factors. Their physiologic functions include blood vessel formation, regulation of vascular permeability, stem cell and monocyte/macrophage recruitment and maintenance of bone homeostasis and repair. In addition, angiogenesis plays a pivotal role in chronic pathologic conditions, such as tumorigenesis, inflammatory immune diseases and bone loss. According to their prevalence, morbidity and mortality, inflammatory diseases affecting periodontal tissues and oral cancer are relevant non-communicable diseases. Whereas oral squamous cell carcinoma (OSCC) is considered one of the most common cancers worldwide, destructive inflammatory periodontal diseases, on the other hand, are amongst the most prevalent chronic inflammatory conditions affecting humans and also represent the main cause of tooth loss in adults. In the recent years, while knowledge regarding the role of VEGF signaling in common oral diseases is expanding, new potential translational applications emerge. In the present narrative review we aim to explore the role of VEGF signaling in oral cancer and destructive periodontal inflammatory diseases, with emphasis in its translational applications as potential biomarkers and therapeutic targets.

Vascular endothelial growth factor polymorphism rs2010963 status does not affect patent ductus arteriosus incidence or cyclooxygenase inhibitor treatment success in preterm infants

BACKGROUND

Vascular endothelial growth factor is critically involved in ductus arteriosus closure. Polymorphisms in the vascular endothelial growth factor gene have been associated with several diseases in neonates and adults.

AIM

Herein, we investigated if vascular endothelial growth factor polymorphism rs2010963 status is associated with patent ductus arteriosus incidence and/or pharmacological treatment success.

METHODS

We assessed rs2010963 status in 814 preterm infants (<1500 g birth weight) by means of restriction fragment length polymorphism analysis. DNA samples were obtained from dry-spot cards used for the German national newborn screening program. Clinical data were obtained by retrospective chart review.

RESULTS

We could not find any statistically significant difference in the incidence of patent ductus arteriosus depending on vascular endothelial growth factor rs2010963 polymorphism status. Furthermore, no statistically significant associations between vascular endothelial growth factor polymorphism rs2010963 status and cyclooxygenase inhibitor treatment success were observed.

CONCLUSION

Our results indicate that there is no association between vascular endothelial growth factor polymorphism rs2010963 status and the occurrence of patent ductus arteriosus or the response to cyclooxygenase inhibitor treatment in a large cohort of preterm infants. Additional studies are needed to determine the role of genetic factors on patent ductus arteriosus incidence and treatment response.

Ibuprofen and indomethacin differentially regulate vascular endothelial growth factor and its receptors in ductus arteriosus endothelial cells

BACKGROUND

Cyclooxygenase inhibitors are widely applied to facilitate ductal closure in preterm infants. The mechanisms that lead to patent ductus arteriosus closure are incompletely understood. Vascular endothelial growth factor plays pivotal roles during ductal closure and remodelling. Aim The aim of this study was to investigate the effects of ibuprofen and indomethacin on the expression of vascular endothelial growth factor and its receptors in a primary rat ductus arteriosus endothelial cell culture.

METHODS

Protein expression of vascular endothelial growth factor and vascular endothelial growth factor receptor 1 and 2 was confirmed in rat ductus arteriosus and aorta by immunofluorescence staining. Fetal rat endothelial cells were isolated from ductus arteriosus and aorta using immunomagnetic cell sorting and treated with ibuprofen or indomethacin. mRNA expression levels were assessed by quantitative polymerase chain reaction analysis.

RESULTS

In ductal endothelial cells, ibuprofen significantly induced vascular endothelial growth factor and its receptor 2, but not receptor 1, whereas indomethacin did not alter the expression levels of the vascular endothelial growth factor system. In contrast, ibuprofen significantly induced vascular endothelial growth factor and its receptors 1 and 2 in aortic endothelial cells, whereas indomethacin only induced vascular endothelial growth factor receptor 2.

CONCLUSION

Our results indicate differential effects of ibuprofen and indomethacin on the expression levels of the vascular endothelial growth factor system in ductus arteriosus endothelial cells. In addition, vessel-specific differences between ductal and aortic endothelial cells were found. Further in vivo studies are needed to elucidate the biological significance of these findings.

Recent Advances in the Treatment of Preterm Newborn Infants with Patent Ductus Arteriosus

A patent ductus arteriosus (PDA) is associated with several adverse clinical conditions. Several strategies for PDA treatment exist, although data regarding the benefits of PDA treatment on outcomes are sparse. Moreover, the optimal treatment strategy for preterm neonates with PDA remains subject to debate. It is still unknown whether and when PDA treatment should be initiated and which approach (conservative, pharmacologic, or surgical) is best for individual patients (tailored therapies). This article reviews the current strategies for PDA treatment with a special focus on recent developments such as oral ibuprofen, high-dose regimens, and the use of paracetamol (oral, intravenous).

Thrombocytopenia in the first 24 hours after birth and incidence of patent ductus arteriosus

BACKGROUND

Experimental studies suggest that platelet-triggered ductal sealing is critically involved in definite ductus arteriosus closure. Whether thrombocytopenia contributes to persistently patent ductus arteriosus (PDA) in humans is controversial. This was a retrospective study of 1350 very low birth weight (VLBW; <1500 g) infants, including 592 extremely low birth weight (ELBW; <1000 g) infants.

METHODS

All infants who had a platelet count in the first 24 hours after birth and an echocardiogram performed on day of life 4 to 5 were included. The incidence of thrombocytopenia was analyzed in infants with and without PDA, and in those who did or did not undergo PDA intervention. The impact of thrombocytopenia, gestational age, birth weight, gender, and sepsis on PDA was determined by receiver operating characteristic curve, odds ratio, and regression analyses.

RESULTS

Platelet numbers within the first 24 hours after birth did not differ between VLBW/ELBW infants with and without spontaneous ductal closure. Platelet numbers were not associated with subsequent PDA treatment. Low platelet counts were not related to failure of pharma-cologic PDA treatment and the need for subsequent surgical ligation. Lower gestational age or birth weight, male gender, and sepsis were linked to the presence of PDA in VLBW infants on day of life 4 to 5.

CONCLUSIONS

Thrombocytopenia in the first 24 hours after birth was not associated with PDA in this largest VLBW/ELBW infant cohort studied to date. Impaired platelet function, due to immaturity and critical illness, rather than platelet number, might play a role in ductus arteriosus patency.

Managing the patent ductus arteriosus in the premature neonate: a new look at what we thought we knew

Over recent years, the clinical approach to patency of the ductus arteriosus in the premature neonate has been the subject of intensive reevaluation. What had once been considered inherently obvious is no longer to be taken for granted. In this review we will focus on some of the controversies surrounding various aspects of the pharmacologic treatment regimens for patent ductus arteriosus closure. The pros and cons of prophylactic vs therapeutic indomethacin, of early vs late therapy, of high- vs low-dose indomethacin, of single vs multiple courses of treatment, and of ibuprofen vs indomethacin will be considered. In addition, the possibility that patency of the ductus arteriosus is merely a physiological manifestation of extreme prematurity, and thus does not necessarily need to be therapeutically closed, has become a viable approach in some cases. As such, we will examine echocardiographic and biochemical criteria aimed at determining the clinical and hemodynamic significance of ductal shunting, and thereby of the need to treat. Finally, we speculate on potential therapeutic directions for the future, including individualized treatment regimens and multidrug treatment cocktails for those who fail initial monodrug therapy.

Isolation and culture of fibroblasts, vascular smooth muscle, and endothelial cells from the fetal rat ductus arteriosus

The ductus arteriosus (DA), a fetal arterial shunt vessel between the proximal descending aorta and the pulmonary artery, closes shortly after birth. Initial functional closure as a result of the DA's smooth muscle contraction is followed by definite anatomical closure. The latter involves several complex mechanisms like endothelial cushion formation and smooth muscle cell migration resulting in fibrosis and sealing of the vessel. These complex steps indicate highly specialized functions of the DA vascular smooth muscle cells (VSMCs), endothelial cells, and fibroblasts. Herein, we describe a new reproducible method for isolating VSMCs, endothelial cells, and fibroblasts of high viability from fetal rat DA using immunomagnetic cell sorting. Purity of the different cell cultures was assessed by immunohistochemistry and flow cytometry and ranged between 85 and 94%. The capability of the VSMCs to react to hypoxic stimuli was assessed by intracellular calcium and ATP measurements and by VEGF mRNA expression analysis. VSMCs respond to hypoxia with decreases in intracellular calcium concentrations and ATP levels, whereas VEGF mRNA expression increased 3.2-fold. The purified vessel-specific different cell types are suitable for subsequent gene expression profiling and functional studies and provide important tools for improving our understanding of the complex processes involved in the closure of the DA.