Circulation research
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Circulation research · Jun 2005
Overexpression of VEGF-C causes transient lymphatic hyperplasia but not increased lymphangiogenesis in regenerating skin.
Vascular endothelial growth factor (VEGF)-C is necessary for lymphangiogenesis and holds potential for lymphangiogenic therapy in diseases lacking adequate lymphatic drainage. However, the ability of VEGF-C to enhance sustainable, functional lymphatic growth in adult tissues remains unclear. To address this, we evaluated VEGF-C overexpression in adult lymphangiogenesis in regenerating skin. ⋯ Furthermore, the hyperplasia disappeared when VEGF-C levels diminished, which occurred after 25 days, rendering the lymphatics indistinguishable from those in control groups. In vitro, we showed that whereas cell-derived VEGF-C could induce chemoattraction of LECs across a membrane (which involves amoeboid-like transmigration), it did not increase LEC chemoinvasion within a 3-dimensional fibrin matrix (which requires proteolytic migration). These results suggest that whereas excess VEGF-C may enhance early LEC proliferation and cause lymphatic vessel hyperplasia, it does not augment the physiological rate of migration or functionality, and by itself cannot sustain any lasting effects on lymphatic size, density, or organization in regenerating adult skin.
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Circulation research · Jun 2005
HMG-CoA reductase inhibitors inhibit endothelial exocytosis and decrease myocardial infarct size.
Three-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors protect the vasculature from inflammation and atherosclerosis by cholesterol dependent and cholesterol independent mechanisms. We hypothesized that HMG-CoA reductase inhibitors decrease exocytosis of Weibel-Palade bodies, endothelial cell granules whose contents promote thrombosis and vascular inflammation. We pretreated human aortic endothelial cells with simvastatin for 24 hours, then stimulated the cells with thrombin, and measured the amount of vWF released into the media. ⋯ However, simvastatin did not affect exocytosis and inflammation in myocardial infarcts of eNOS knockout mice. Inhibition of endothelial exocytosis is a novel mechanism by which HMG-CoA reductase inhibitors may reduce vascular inflammation, inhibit thrombosis, and protect the ischemic myocardium. These findings may explain part of the pleiotropic effects of statin therapy for patients with cardiovascular disease.