iPSC-RPE patch restores photoreceptors and regenerates choriocapillaris in a pig retinal degeneration model.

Dry age-related macular degeneration (AMD) is a leading cause of untreatable vision loss. In advanced cases, retinal pigment epithelium (RPE) cell loss occurs alongside photoreceptor and choriocapillaris degeneration. We hypothesized that an RPE-patch would mitigate photoreceptor and choriocapillaris degeneration to restore vision. An induced pluripotent stem cell-derived RPE (iRPE) patch was developed using a clinically compatible manufacturing process by maturing iRPE cells on a biodegradable poly(lactic-co-glycolic acid) (PLGA) scaffold. To compare outcomes, we developed a surgical procedure for immediate sequential delivery of PLGA-iRPE and/or PLGA-only patches in the subretinal space of a pig model of laser-induced outer retinal degeneration. Deep learning algorithm-based optical coherence tomography (OCT) image segmentation verified preservation of the photoreceptors over the areas of PLGA-iRPE-transplanted retina and not in laser-injured or PLGA-only-transplanted retina. Adaptive optics imaging of individual cone photoreceptors further supported this finding. OCT-angiography revealed choriocapillaris regeneration in PLGA-iRPE- and not in PLGA-only-transplanted retinas. Our data, obtained using clinically relevant techniques, verified that PLGA-iRPE supports photoreceptor survival and regenerates choriocapillaris in a laser-injured pig retina. Sequential delivery of two 8 mm2 transplants allows for testing of surgical feasibility and safety of the double dose. This work allows one surgery to treat larger and noncontiguous retinal degeneration areas.