Intravitreal Injection of AAV Expressing Soluble VEGF Receptor-1 Variant Induces Anti-VEGF Activity and Suppresses Choroidal Neovascularization

Abstract

PURPOSE. With anti-VEGF-based treatments for wet AMD requiring frequent injections, it is often burdensome to both patients and healthcare providers. To explore its possibility as a desirable alternative, we investigated the therapeutic potential of a recombinant adenoassociated virus 2 expressing a soluble variant of VEGF receptor-1 (rAAV2-sVEGFRv-1) in a laser-induced choroidal neovascularization (CNV) model, as CNV is a defining feature of AMD progression. METHODS. C57/B6 mice were intravitreally administered with rAAV2-sVEGFRv-1, rAAV2-GFP, or clinically used bevacizumab after CNV lesions were induced via laser photocoagulation. Immunostaining was performed with phalloidin and CD31 to measure CNV extensiveness, F4/80 and CD11b for inflammatory cell infiltration, and pan-cytokeratin to visualize fibrotic progression. RESULTS. rAAV2-sVEGFRv-1 (5.0 x 10(7) viral genomes) possesses antiangiogenic, antiinflammatory, and antifibrotic properties. rAAV2-sVEGFRv-1 was demonstrated to significantly decrease retinal CNV lesion size (1336 +/- 186) when compared to rAAV2-GFP-treated (2949 +/- 437, P = 0.0043), mock-treated (3075 +/- 265, P = 0.0013), and bevacizumab-treated models (995 +/- 234). Infiltration by inflammatory cells significantly decreased with rAAV2sVEGFRv- 1 administration, while groups treated with rAAV2-GFP did not. Additionally, antiapoptotic activity was observed via TUNEL assay in rAAV2-sVEGFRv-1 (16.0 +/- 3.6) and rAAV2-GFP (46.0 +/- 7.5, P = 0.003). Overall, the rAAV2-sVEGFRv-1 viral vector was positively comparable to bevacizumab, indicating it as effective as approved therapeutics. CONCLUSIONS. The ability of a low dose of rAAV2-sVEGFRv-1 to exert a therapeutically relevant anti-VEGF effect in a CNV model is demonstrated, and strongly suggests gene therapy as an effective and convenient treatment for sustained VEGF suppression.