Dose-Dependent Effect of Pitavastatin on VEGF and Angiogenesis in a Mouse Model of Choroidal Neovascularization

Abstract

PURPOSE. To evaluate the relation between statin therapy, vascular endothelial growth factor (VEGF) expression, vascular leakage, and CNV size in experimentally induced choroidal neovascularization (CNV). METHODS. Wild-type (C57 Bl/6J) mice received pitavastatin 0.18 mg/kg per day (group 1), 1.8 mg/kg per day (group 2) or 18 mg/kg per day (group 3) for 3 days before laser-induced CNV and continued to receive the drug for 14 days. Serum total cholesterol levels were measured by spectrophotometry. Fluorescein angiograms were graded by masked observers. VEGF protein levels from retinal lysates were measured and CNV area was assessed by histology. RESULTS. Pitavastatin did not reduce total serum cholesterol at any of the doses used. The incidence rate ratios for development of clinically significant CNV leakage was 0.62 (95% CI, 0.46 -0.84) for group 1, 0.56 (95% CI, 0.28 -1.10) for group 2, and 1.22 (95% CI, 1.01-1.48) for group 3 (P ϭ 0.002, 0.09, and 0.04, respectively). Mean CNV area increased by 13%, 22%, and 95% in groups 1, 2, and 3, respectively (P Ͼ 0.05). Normalized VEGF levels did not mirror the observed changes in fluorescein leakage and CNV area in histologic examination. 1 An essential element in the development of CNV is the rupture of Bruch's membrane and the proliferation of blood vessels through breaks in the membrane. Experimental CNV can be created by laser-induced rupture of Bruch's membrane, which stimulates preexisting capillaries to proliferate into new capillary networks. 2 There are a large number of specific proteins involved in angiogenesis that interact in complex ways, and their expression depends on the surrounding cell types. In the recent past, considerable attention has been directed to the lipid-lowering independent effects of 3 hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, generally called statins. The available data from population and case series 3-12 investigations of the effect of statins on visual loss from exudative AMD is controversial. Furthermore, initial reports by Kureishi et al. 13 Subsequent reports from Vincent et al. 14 demonstrated that another statin, cerivastatin, has antiangiogenic activity. Cerivastatin inhibits mitogen-induced endothelial migration. This effect is attributed to the inhibition of Rho A, which was shown to be mediated by the inhibition of focal adhesion kinase and Akt activation. 15 The resulting controversy about the role of statins in angiogenesis has been addressed in three subsequent reports. 16 -18 Weis et al. 17 Apoptosis was observed in both studies using the higher concentration of statins