Vascular endothelial growth factor (VEGF) is a pleiotropic growth factor that binds a broad spectrum of cell types and regulates diverse cellular processes, including angiogenesis, growth and ...survival. However, it is technically difficult to quantify VEGF-cell binding activity because of reversible nature of ligand-receptor interactions. Here we used T7 bacteriophage display to quantify and compare binding activity of three human VEGF-A (hVEGF) isoforms, including hVEGF111, 165 and 206. All three isoforms bound equally well to immobilized aflibercept, a decoy VEGF receptor. hVEGF111-Phage exhibited minimal binding to immobilized heparan sulfate, whereas hVEGF206-Phage and hVEGF165-Phage had the highest and intermediate binding to heparan, respectively. In vitro studies revealed that all three isoforms bound to human umbilical vein endothelial cells (HUVECs), HEK293 epithelial and SK-N-AS neuronal cells. hVEGF111-Phage has the lowest binding activity, while hVEGF206-Phage has the highest binding. hVEGF206-Phage was the most sensitive to detect VEGF-cell binding, albeit with the highest background binding to SK-N-AS cells. These results suggest that hVEGF206-Phage is the best-suited isoform to quantify VEGF-cell binding even though VEGF165 is the most biologically active. Furthermore, this study demonstrates the utility of T7 phage display as a platform for rapid and convenient ligand-cell binding quantification with pros and cons discussed.
•A method to quickly quantify VEGF binding to cells, receptor and heparan.•All three VEGF isoforms, including VEGF111, 165 and 206, can be readily quantified.•VEGF206 isoform shows the highest binding to cells and heparan sulfate.•VEGF165 isoform has the intermediate binding to cells and heparan.•VEGF111 isoform show the lowest binding to cells and heparan.
To assess the rate and risk factors for reactivation of retinopathy of prematurity (ROP) after intravitreal injection (IVI) of antivascular endothelial growth factor (VEGF) agents.
Infants who ...received IVI therapy between 2017 and 2022 were enrolled and divided into 2 groups: those with and without ROP reactivation. Information on ROP variables and patient variables were analyzed using multivariable logistic regression.
A total of 114 infants with 223 eyes were enrolled in the study. The ROP reactivation rate was 11.4% of infants (9.9% of eyes). The mean duration of reactivation was 84 ± 45 days. Among the 223 eyes treated with IVI, reactivation rates were 6% for bevacizumab, 13.9% for aflibercept, and 22.2% for ranibizumab. A multivariable regression model showed that ranibizumab was an independent risk factor (OR 11.4, P = .008) for reactivation. Other risk factors included infants with periventricular leukomalacia (OR 13.8, P = .003), patent ductus arteriosus ligation (OR 10.7, P = .032), and infants who still required invasive mechanical ventilation on the day of IVI therapy (OR 7.0, P = .018).
All anti-VEGF agents carry a risk of ROP reactivation, with the risk being greater with ranibizumab 0.25 mg than with bevacizumab 0.625 mg. Reactivation of ROP should be assessed vigilantly, especially in those infants with increased risks. Future research to determine the optimal anti-VEGF selection and dosage in high-risk infants is warranted.
The vascular endothelial growth factor (VEGF) and its receptor (VEGFR) have been shown to play major roles not only in physiological but also in most pathological angiogenesis, such as cancer. VEGF ...belongs to the PDGF supergene family characterized by 8 conserved cysteines and functions as a homodimer structure. VEGF-A regulates angiogenesis and vascular permeability by activating 2 receptors, VEGFR-1 (Flt-1) and VEGFR-2 (KDR/Flk1 in mice). On the other hand, VEGF-C/VEGF-D and their receptor, VEGFR-3 (Flt-4), mainly regulate lymphangiogenesis. The VEGF family includes other interesting variants, one of which is the virally encoded VEGF-E and another is specifically expressed in the venom of the habu snake (Trimeresurus flavoviridis). VEGFRs are distantly related to the PDGFR family; however, they are unique with respect to their structure and signaling system. Unlike members of the PDGFR family that strongly stimulate the PI3K-Akt pathway toward cell proliferation, VEGFR-2, the major signal transducer for angiogenesis, preferentially utilizes the PLCγ-PKC-MAPK pathway for signaling. The VEGF-VEGFR system is an important target for anti-angiogenic therapy in cancer and is also an attractive system for pro-angiogenic therapy in the treatment of neuronal degeneration and ischemic diseases.
Background
Ischemic stroke is a serious cerebrovascular disease with high morbidity and disability. Zinc accumulation has been shown to play a vital role in neuronal death and blood–brain barrier ...damage following ischemia in acute stage. However, almost nothing is known about whether zinc is involved in neurological recovery in ischemic prolonged period. This study investigates whether zinc promotes neurological recovery through astrocytes‐induced angiogenesis during ischemic repair phase.
Methods
Sprague–Dawley rats were subjected to 2 h ischemia/14, 21, and 28 days reperfusion by middle cerebral artery occlusion, then administered ZnCl2 (10 mg/kg) via intraperitoneally daily from 7 days to tissue collection to observe brain tissue morphology, neurological function recovery by cortical width index, Adhesive removal test, and Forelimb placing test. Angiogenesis, astrocyte activation, and HIF‐1α/VEGF pathway were assessed via Western blot, immunofluorescence, and BrdU method in vivo and in vitro.
Results
The results showed that zinc significantly alleviated brain atrophy and improved neurological function recovery during the cerebral ischemia repair stage. Zinc significantly increased the protein levels of HIF‐1α, VEGF‐A, and VEGF‐R2 in astrocytes, and promoted angiogenesis during cerebral ischemia repair. In vitro and in vivo studies confirmed that zinc promoted angiogenesis via the astrocyte‐mediated HIF‐1α/VEGF signaling pathway.
Conclusions
Zinc significantly improves neurological function recovery during the cerebral ischemia repair stage, providing new evidence supporting zinc as a potential therapeutic target for ischemic stroke by promoting astrocyte induced angiogenesis.
Zinc can alleviate cerebral ischemia atrophy and promote neurological function recovery during cerebral ischemia repair stage.
Zinc promoted angiogenesis via astrocyte‐mediated HIF‐1α/VEGF signaling pathway.
Zinc may serve as a potential therapeutic target for the treatment of functional.
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