scholarly journals Overexpression of Vascular Endothelial Growth Factor in the Avian Embryo Induces Hypervascularization and Increased Vascular Permeability without Alterations of Embryonic Pattern Formation

1995 ◽  
Vol 171 (2) ◽  
pp. 399-414 ◽  
Author(s):  
Ingo Flamme ◽  
Marie von Reutern ◽  
Hannes C.A. Drexler ◽  
Sarwar Syed-Ali ◽  
Werner Risau
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Growth Factor ◽  
Pattern Formation ◽  
Vascular Permeability ◽  
Avian Embryo ◽  
Vascular Endothelial ◽  
Endothelial Growth Factor ◽  
Embryonic Pattern Formation

scholarly journals Vascular Permeability Factor/Vascular Endothelial Growth Factor Induces Lymphangiogenesis as well as Angiogenesis

2002 ◽  
Vol 196 (11) ◽  
pp. 1497-1506 ◽  
Author(s):  
Janice A. Nagy ◽  
Eliza Vasile ◽  
Dian Feng ◽  
Christian Sundberg ◽  
Lawrence F. Brown ◽  
...  
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Growth Factor ◽  
Blood Vessels ◽  
Vascular Permeability ◽  
Malignant Tumors ◽  
Vascular Endothelial ◽  
Vascular Permeability Factor ◽  
Immunodeficient Mice ◽  
Permeability Factor ◽  
Endothelial Growth Factor

Vascular permeability factor/vascular endothelial growth factor (VPF/VEGF, VEGF-A) is a multifunctional cytokine with important roles in pathological angiogenesis. Using an adenoviral vector engineered to express murine VEGF-A164, we previously investigated the steps and mechanisms by which this cytokine induced the formation of new blood vessels in adult immunodeficient mice and demonstrated that the newly formed blood vessels closely resembled those found in VEGF-A–expressing tumors. We now report that, in addition to inducing angiogenesis, VEGF-A164 also induces a strong lymphangiogenic response. This finding was unanticipated because lymphangiogenesis has been thought to be mediated by other members of the VPF/VEGF family, namely, VEGF-C and VEGF-D. The new “giant” lymphatics generated by VEGF-A164 were structurally and functionally abnormal: greatly enlarged with incompetent valves, sluggish flow, and delayed lymph clearance. They closely resembled the large lymphatics found in lymphangiomas/lymphatic malformations, perhaps implicating VEGF-A in the pathogenesis of these lesions. Whereas the angiogenic response was maintained only as long as VEGF-A was expressed, giant lymphatics, once formed, became VEGF-A independent and persisted indefinitely, long after VEGF-A expression ceased. These findings raise the possibility that similar, abnormal lymphatics develop in other pathologies in which VEGF-A is overexpressed, e.g., malignant tumors and chronic inflammation.

Abstract 326: Granzyme B Releases Vascular Endothelial Growth Factor from Extracellular Matrix Stores and Induces Vascular Permeability in vivo

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Alon Hendel ◽  
David J Granville
Keyword(s):  
Extracellular Matrix ◽  
Vascular Endothelial Growth Factor ◽  
Growth Factor ◽  
Vascular Permeability ◽  
Chronic Inflammation ◽  
Granzyme B ◽  
Vascular Endothelial ◽  
Endothelial Growth Factor ◽  
Vegf Release

Introduction The formation of unstable and leaky neovessels underlies the pathogenesis of a large number of chronic inflammatory diseases. Granzyme B (GZMB) is a serine protease that is expressed and released by a variety of immune cells and accumulates in the extracellular matrix (ECM) during chronic inflammation where it cleaves a number of ECM proteins, including fibronectin (FN). Vascular endothelial growth factor (VEGF) is a potent vascular permeabilizing agent that is sequestered in the ECM by binding FN in both normal and diseased tissue. We hypothesize that GZMB cleavage of FN will release VEGF from its extracellular stores and promote vascular permeability as a mechanism that contributes to neovessel leakage during chronic inflammation. Methods GZMB-mediated VEGF release from either FN coated wells or endogenously produce endothelial cell (EC) matrix was measured by VEGF ELISA. VEGF-release supernatants were used to treat EC and VEGF receptor 2 (VEGFR2) activation was evaluated by immunoblotting for phosphorylated VEGFR2. Evan’s blue was injected intravenously to CD1 mice followed by ear injection of either mouse GZMB, saline control, GZMB + neutralizing mouse VEGF antibody or GZMB+ IgG control (n=5 for each experimental group). Vascular leakage was evaluated by Evan’s blue dye extraction. Results GZMB effectively releases VEGF from both FN and from EC matrix, while inhibition of GZMB prevented VEGF release. GZMB-mediated VEGF release resulted in significant activation of VEGFR2 in EC monolayer signified by increased VEGFR2 phosphorylation. GZMB ear injection resulted in a significant increase in vascular permeability in vivo. Importantly, co-injection of GZMB and neutralizing mouse VEGF antibody significantly reduced vascular leakage compared to co-injection of GZMB and matching IgG control. Conclusions and Impact GZMB increases VEGF bioavailability by releasing it from the ECM leading to VEGFR2 activation and increased vascular permeability in vivo. These findings present a novel role for GZMB as a modulator of vascular response during chronic inflammation.

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