Abstract
Purpose::
The fibronectin receptor a5b1 integrin was shown to be essential for angiogenesis in eyes and tumors. The highly potent and selective a5b1 small molecule inhibitor JSM6427 was evaluated in a variety of in vitro and in vivo models. To prove the dose dependent anti-angiogenic activity in the eye, relevant models for AMD were performed in rabbit and Cynomolgus monkey.
Methods::
The compound was characterized in vitro using cell adhesion, phosphorylation and tube formation assays. For in vivo characterization a laser-induced CNV model in monkey and a growth factor induced CNV model in rabbit were performed. The experimental CNV in rabbit was induced by implantation of a VEGF/bFGF Hydron pellet within the suprachoroidal space. In both models different doses of intravitreal injections of JSM6427 (100, 300 and 1000 µg/eye) or vehicle were administered on Day 1, 8, 15, and 22. Weekly fluorescein angiographies (FA) were performed over the time course of 4 weeks, to evaluate the extent of neovascularization as determined by the leakage of fluorescein through neovessels, the validated endpoint of CNV in these models. Additionally, further parameters were analyzed (ERG, biomicroscopy, histopathology) to evaluate the safety of repeated intravitreal injections of JSM6427.
Results::
Selective a5b1 small molecule inhibitor JSM6427 showed clear inhibitory activity in several binding and functional cellular assays in the nanomolar range. Additionally, JSM6427 inhibits migration of activated endothelial and ARPE-19 cells.In both in vivo models weekly intravitreal injections of JSM6427 showed very similar results with a clear dose dependent inhibition of choroidal neovascularization. Ophthalmologic and histopathological examinations showed that no adverse effects were observed related to the repeated intravitreal administration of JSM6427.
Conclusions::
Intravitreal injection of JSM6427 prevents dose dependently neovascularization as determined in two different CNV models. Thus, the inflammatory triggered laser induced CNV in monkey and growth factor induced CNV in rabbit can be prevented via inhibition of a5b1 integrin. Therefore, the a5b1 small molecule inhibitor JSM6427 provides a new approach for inhibition of AMD as well as other neovascular diseases in the eye.
Keywords: choroid: neovascularization • age-related macular degeneration • neovascularization