Abstract
Purpose: :
The goal of this study was to follow the natural history of experimental monkey CNV after suprachoroidal sustained release of both VEGF and bFGF. Part 2. Natural History of Experimental CNV in Non-Human Primates.
Methods: :
In this pilot monkey study (N = 5), either non-biodegradable placebos or VEGF/bFGF implants that are shown to produce in the rabbit progressive CNV after suprachoroidal implantation (Zahn et al.), were used. One monkey eye initially was implanted with the VEGF/bFGF pellet to establish the procedure and define preliminary histology. In the other monkeys (N=4) subsequent implants, 1x or 2x VEGF/bFGF in the OD eyes or placebo in the OS eyes, were placed suprachoroidally, within 2 disc diameters of the macula. One day post implant, with a Kryptom-red laser, 3 spots were placed on retinas next to each pellet. In the following 14 wks, all monkeys were anesthetized and monitored with color fundus photography, fluorescein angiography, multifocal ERG, and spectral domain OCT. At either wk 7 or wk 14, eyes were enucleated and then placed in neutral buffered formalin for several days. Following dissection, areas containing the macula, laser burns, and VEGF/bFGF implants were processed and embedded into paraffin for appropriate serial dissection and then stained with hematoxylin and eosin.
Results: :
Fluorescein leakage was seen around the laser spots and above the implants in all eyes that had VEGF/bFGF implants from wk 1 up to wk 14 with varying intensities. Fluorescein leakage was not observed in placebo-implanted eyes. In 2 eyes, the florid leak peaked at wk 8 and included vessel tortuosity. In the other 2 eyes, leakage was less and the pattern was reminiscent of plypoidal choroidal vasculopathy. In OD eyes, at both 100X and 200X, dilated blood vessels by the VEGF/bFGF implant could be seen in the choroidal layer not far from the macula. Laser burns demonstrated severe disruption of both retina and choroid. Normal-appearing maculas were found in all OS eyes.
Conclusions: :
Experimental intra-CNV can be induced in the non-human primate eye through a VEGF/bFGF implant within the suprachoroidal space.
Keywords: choroid: neovascularization • retinal neovascularization • choroid