Abstract
Purpose :
Current treatment of exudative age-related macular degeneration (eAMD) aims at antagonizing the effect of vascular endothelial growth factor (VEGF) which is a known driver of choroidal neovascularization (CNV) in the disease. However, injections should be administered repeatedly with an accumulation of adverse effects. Gene therapy has been shown to effectively reduce the expression of VEGF for a longer period in a murine model of CNV. The technique should be brought closer to clinical translation in a porcine model, but laser induced subretinal CNV in pigs have a low success rate, since the laser burns also damage the neuroretina. Therefore, we developed a method using subretinal injection of saline prior to laser application, to protect the neuroretina from thermic burns resulting from the retinal laser by separating it from the underlying retinal pigment epithelium (RPE).
Methods :
In 30 freshly enucleated porcine eyes the protection sleeve of a venflon was introduced through a pars plana incision into the vitreous body until the tip was 1 mm from the posterior retina, a subretinal cannula (Poly Tip Cannula 23g/38g) was introduced into the sleeve to be advanced to penetrate the retinal surface, followed by injection of 0,05 ml saline producing a retinal bleb. Subsequently, laser burns (810 nm, spotsize 600 mm, 1 W for 1 sec) were applied to the retina in the area of the detached neuroretina. Ophthalmoscopy was performed to examine the neuroretina for possible damage caused by the laser.
Results :
In all eyes the subretinal injection of saline was successful, and ophthalmoscopy showed that the neuroretina was unaffected by the laser applications.
Conclusions :
Transvitreal subretinal injection of saline in porcine eyes can detach the retina to protect the neuroretina from laser burns intended to produce choroidal neovascularization. Further studies will have to evaluate this method in an in vivo porcine model. This may facilitate the development of experimental CNV with a high success rate in the porcine eye as a precondition for developing gene therapy to treat eAMD.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.