Empty E1–, E3–, E4+ and Empty E1–, E3–, E4– Adenoviral Vectors Inhibit Retinal Neovascularization

Abstract

Abstract: : Purpose: Previously, we had found that empty adenoviral vectors also have some anti–neovascular activity in addition to that of the antiangiogenic factor, pigment epithelium–derived factor (Mori, et al, 2001). To further understand and quantify the antiangiogenic effect of empty E1^–, E3^–, E4⁺ and E1^–, E3^–, E4^–, serotype 5, adenoviral vectors on retinal neovascularization, we evaluated the gene expression profile of each vector following intravitreous injection. Methods: C57BL/6 mouse pups were exposed to 75% oxygen from post–natal day (P) 7 to 12 and then returned to room air. Intravitreous injection of 1x10⁹ particles of empty E1^–, E3^–, E4⁺, empty E1^–, E3^–, E4^– adenoviral vector or vehicle was performed on P10. Histopathological evaluation, quantitative analysis of retinal neovascularization, microarray and qRT–PCR analysis was performed on eyes from each group. Results: Retinal neovascularization was significantly reduced after intravitreous injection of empty E1^–, E3^–, E4⁺ and empty E1^–, E3^–, E4^– adenoviral vectors (p<0.001, 83% reduction and p<0.01, 43% reduction, respectively). Statistical analyses identified 48 genes that were determined to be preferentially expressed in vector injected eyes. These included, but were not limited to, CC/CXC chemokines and ESTs. Conclusions: The data quantify and may explain the relative antiangiogenic effect of empty E1^–, E3^–, E4⁺ and E1^–, E3^–, E4^– adenoviral vectors in the setting of retinal neovascularization only. Data from microarray and qRT–PCR analysis have identified 48 over–expressed genes that may contribute to the antiangiogenic activity. Last, these data suggest that adenovector–delivered antiangiogenic compounds in some disease states may provide additional benefit than initially recognized.

Keywords: adenovirus • cytokines/chemokines • gene transfer/gene therapy