Chemical mediators of intraocular neovascularization

Intraocular neovascularization occurs in several ocular disorders. Evidence from clinical experimental observations suggests that the retina and the vitreous are potential sources of angiogenic stimulators and inhibitors which may play a role in the development of intraocular neonvascularization. We have demonstrated that extracts of adult retina are capable of stimulating vasoproliferation on the chick chorioallantoic membrane (CAM) and that extracts of adult vitreous inhibit this response. In addition, extracts of adult retina are capable of stimulating vascular endothelial cell proliferation and chemotaxis in vitro. The relationship of these findings to human disease is as yet unknown. However, we have found a good correlation between the presence of retinal, optic disc, and/or iris neovascularization in eyes undergoing therapeutic vitrectomy and the ability of intraocular fluid from these eyes (obtained at the time of surgery) to stimulate vasoproliferation on the CAM As well as thymidine uptake of vascular endothelial cells in culture. Further studies will be necessary to determine the relationship of these different findings to human intraocular neovascularization.