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VEGF induces NO-dependent hyperpermeability in coronary venules
1Microcirculation Research Institute, Texas A&M University Health Science Center, Temple 76504, USA.
The American Journal of Physiology
|December 1, 1996
Summary
Vascular endothelial growth factor (VEGF) increases microvascular permeability by activating nitric oxide (NO) synthesis, guanylate cyclase (GC), and protein kinase G (PKG). This pathway is crucial for regulating blood vessel permeability.
Area of Science:
- Physiology
- Molecular Biology
- Cardiovascular Research
Background:
- Microvascular permeability is critical for regulating fluid and solute exchange.
- Vascular Endothelial Growth Factor (VEGF) is a key regulator of angiogenesis and vascular function.
- Understanding VEGF's signaling pathways is essential for therapeutic development.
Purpose of the Study:
- To investigate the direct impact of VEGF on microvascular permeability.
- To elucidate the specific signaling mechanisms mediating VEGF's effects on permeability.
- To determine the roles of nitric oxide (NO), guanylate cyclase (GC), and protein kinase G (PKG) in VEGF-induced permeability.
Main Methods:
- Isolated coronary venules were used to measure albumin permeability.
- VEGF was applied topically to assess its dose-dependent effects.
- Inhibitors of NO synthesis (NG-monomethyl-L-arginine), GC (1H-[1,2,4]oxadiazolo[4,3-alpha]quinoxalin-1-one), and PKG (KT-5823) were employed.
Main Results:
- VEGF dose-dependently increased albumin permeability in venules by two- to threefold.
- Inhibition of NO synthesis abolished the VEGF-induced hyperpermeability.
- Inhibiting GC and PKG prevented the hyperpermeability response to VEGF, also reducing basal permeability.
Conclusions:
- VEGF directly modulates microvascular permeability.
- The signaling cascade involves NO synthesis, GC stimulation, and PKG activation.
- These findings highlight a novel pathway for controlling vascular permeability.