Abstract
Purpose :
The death of retinal pigment epithelial (RPE) cells in geographic atrophy (GA) is a leading cause of blindness with no cure. GA results in RPE death and progressive central vision loss. GelRPE is a novel, integrated photo-crosslinked hydrogel-RPE cell therapy designed to restore vision in GA patients. GelRPE is injected sub-retinally as a liquid and crosslinked in situ into a solid soft gel. GelRPE improves upon existing saline formulations by creating a favorable environment for RPE cells and localizing cells at the target site, enabling tissue regeneration and potentially vision restoration. The feasibility of GelRPE delivery compared to standard saline formulations were evaluated in a 28-day porcine model.
Methods :
Twelve Yorkshire pigs were segregated into four groups: three GelRPE formulations (shorter and longer persisting, clinical and 5x cell dose) and a RPE saline injection (control clinical dose). Three pigs (six eyes) were treated in each group with a 200 µL subretinal injection using standard cannulas (MedOne Subretinal PolyTip® Cannula). The GelRPE test articles were injected as a liquid, and the existing vitrectomy light source (Alcon Constellation®) was then focused on the injected material for 30 s, crosslinking it into a solid gel. Ocular exams, optical coherence tomography (OCT), and color fundus imaging were performed throughout the duration of the study with eyes collected for histopathology (H&E) and immunohistochemistry (IHC) at day 28.
Results :
Subretinal injections were achieved for all subjects, creating RPE cell sub-retinal blebs. GelRPE test articles successfully crosslinked into solid hydrogels using the vitrectomy light source, as the crosslinked gel fluoresces and was visible in post-operative color fundus imaging. Test articles were generally well tolerated. At day 28, there was evidence of viable, human RPE cells in the sub-retinal space of GelRPE subjects as confirmed by IHC. Additionally, indication of pigmented cells were observed in GelRPE treated eyes, via color fundus imaging; indicative of maturing RPE. Human RPE cells were not observed subretinally in subjects receiving RPE saline injections.
Conclusions :
GelRPE was able to deliver viable RPE cells and localize them at the target location, avoiding cell migration, compromised cell viability, and uneven cell distribution seen with cells delivered via a saline solution.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.