EIAV vector-mediated delivery of endostatin or angiostatin inhibits angiogenesis and vascular hyperpermeability in experimental CNV

We evaluated the efficacy of equine infectious anaemia virus (EIAV)-based lentiviral vectors encoding endostatin (EIAV. endostatin) or angiostatin ( EIAV. angiostatin) in inhibiting angiogenesis and vascular hyperpermeability in the laser-induced model of choroidal neovascularisation (CNV). Equine infectious anaemia virus. endostatin, EIAV. angiostatin or control ( EIAV. null) vectors were administered into the subretinal space of C57BI/6J mice. Two weeks after laser injury CNV areas and the degree of vascular hyperpermeability were measured by image analysis of in vivo fluorescein angiograms. Compared with EIAV.null-injected eyes, EIAV. endostatin resulted in a 59.5% (P < 0.001) reduction in CNV area and a reduction in hyperpermeability of 25.6% ( P < 0.05). Equine infectious anaemia virus. angiostatin resulted in a 50.0% (P < 0.05) reduction in CNV area and a 23.9% (P < 0.05) reduction in hyperpermeability. Equine infectious anaemia virus. endostatin, but not EIAV. angiostatin significantly augmented the frequency of apoptosis within the induced CNV as compared with injected controls. TdT-dUTP terminal nick end labeling analysis 5 weeks post-injection, and histological and retinal flatmount analysis 12 months post-injection revealed no evidence of vector- or transgene expression-related deleterious effects on neurosensory retinal cells, or mature retinal vasculature in non-lasered eyes. Highly expressing EIAV-based vectors encoding endostatin or angiostatin effectively control angiogenesis and hyperpermeability in experimental CNV without long-term deleterious effects, supporting the use of such a strategy in the management of patients with exudative age-related macular degeneration.