Induction of Vascular Endothelial Growth Factor in Balloon-Injured Baboon Arteries

Abstract

Neovascularization is a hallmark of neointimal formation in atherosclerotic plaques and restenotic lesions. Vascular endothelial growth factor (VEGF) promotes neovascular growth, whereas oxidative stress is a potent factor in vascular cell proliferation. To investigate the mechanisms of neovascular formation, we treated human and rat vascular smooth muscle cells (VSMCs) with H2O2. Northern blot analysis demonstrated a dose- and time-dependent increase in VEGF mRNA, with a maximum of 4-fold at 3 hours (200 mumol/L). As determined by immunoblotting and enzyme-linked immunosorbent assay, VEGF protein expression and secretion were similarly increased. Human umbilical vein endothelial cells were treated with conditioned medium from VSMCs incubated with 200 mumol/L H2O2. DNA synthesis, measured by thymidine incorporation, was increased 4-fold compared with control, an effect that was blocked by a neutralizing anti-VEGF antibody. The lipid peroxidation product 4-hydroxynonenal (1 mumol/L), an endogenous reactive oxygen species present in human atherosclerotic lesions, also increased VEGF secretion in VSMCs in a similar time-dependent fashion. Immunohistochemical staining and in situ hybridization of aortic sections from balloon-injured baboons demonstrated increased VEGF expression in discrete areas of the neointima and media compared with control sections, and expression correlated with the generation of 4-hydroxynonenal. Regulators of VEGF expression, such as reactive oxygen species, may enhance neovascularization of atherosclerotic and restenotic arteries.

Contribution of Aldose Reductase to Diabetic Hyperproliferation of Vascular Smooth Muscle Cells

“…Previous studies have shown that balloon-injured arteries display higher levels of protein-HNE adducts (24). In agreement with these findings, we observed that the proliferative regions of the neointima were intensely stained with anti-protein-HNE antibody.…”

“…Hence inhibition of aldose reductase could increase oxidative stress. Protein adducts of aldehydes accumulate in neointimal lesions in balloon-injured arteries (24), and our previous results show that that HNE is a potent SMC mitogen (43). Hence increased formation of HNE or related electrophiles could be one mechanism for stimulating SMC growth in arterial lesions.…”

NADPH Oxidase-Derived Overproduction of Reactive Oxygen Species Impairs Postischemic Neovascularization in Mice with Type 1 Diabetes

“…NADPH oxidase activity and ROS production mediate angiogenesis in both cultured cells and in vivo models of neovascularization. 13,14 A recent study also shows that vessel growth in ischemic hindlimbs is significantly hampered in mice lacking gp91 phox . 15 We could confirm these previous studies, because we found that NAC administration and gp91 phox deficiency reduced postischemic neovascularization.…”

“…H 2 O 2 stimulates cell migration and proliferation in endothelial cells, 12 and ROS directly modulate VEGF-A expression and vascular smooth muscle cell proliferation. 13 Previous reports also suggest that both the gp91 phoxcontaining NADPH oxidase and Rac1 play a major role in VEGF-A-induced endothelial cell proliferation.…”

Vascular Endothelial Growth Factor Induces Heparin-binding Epidermal Growth Factor-like Growth Factor in Vascular Endothelial Cells

“…The induction of VEGF and its receptors (flk-1 and flt) in human atherosclerotic lesions and in animal models of arterial injury has also been described (37,47,48). Lazarous et al (49) reported recently that VEGF given postoperatively in a canine model of left circumflex coronary artery occlusion and iliofemoral artery denudation induced further accumulation of neointima without inducing collateral blood vessel formation in the coronary circulation.…”