Abstract
Purpose::
To investigate the ciliary body as a potential source of this growth factor in patients with neovascular glaucoma
Methods::
Excessive production of VEGF induces anterior segment neovascularization that may manifest as neovascular glaucoma (NVG). We processed 12 human eyes enucleated for uncontrolled NVG for immunodetection of VEGF protein and hybridization in situ to localize its mRNA.
Results::
Compared with age-matched normal eyes, a strongly positive (15-fold greater) immunoreaction was observed in the nonpigmented ciliary epithelial cells of NVG eyes. Negative control sections, in which nonimmune serum was substituted for the anti-VEGF antibody, showed no immunostaining. Minimal or no staining for VEGF mRNA was detected in ocular tissues of control eyes. In contrast, eyes with neovascular glaucoma revealed strong staining (6-fold greater) for VEGF mRNA in the nonpigmented ciliary epithelium. VEGF mRNA expression was also observed in the ganglion cell, inner nuclear and outer nuclear layers of the retina in eyes with rubeosis iridis. Adjacent sections hybridized with VEGF sense probe showed minimal background staining.
Conclusions::
Our findings identify an extraretinal source for the synthesis of VEGF in eyes with uncontrolled NVG and could account for increased levels of VEGF protein in the aqueous humor that we reported previously (Ophthalmology 105:232-7, 1998). It may also explain why pan-retinal photocoagulation does not induce regression of iris neovascularization in all patients with venous thrombosis and/or diabetic retinopathy. Our investigations provide a rationale for ciliary body ablation as a treatment for neovascular glaucoma.
Keywords: neovascularization • retinal neovascularization • vascular occlusion/vascular occlusive disease