Validation of iPS Cell-Derived RPE Tissue in Animal Models

Previous work suggests that replacing diseased Retinal Pigment Epithelium (RPE) with a healthy autologous RPE sheet can provide vision rescue for AMD patients. We differentiated iPSCs into RPE using a directed differentiation protocol. RPE cells at the immature RPE stage were purified and seeded onto either electrospun poly(lactic-co-glycolic acid) (PLGA) scaffolds or non-biodegradable polyester cell culture inserts and compared the two tissues. In vitro, PLGA and polyester substrates produced functionally similar results. Following in vitro evaluation, we tested RPE tissue in animal models for safety and function. Safety studies were conducted in RNU rats using an injection composed of intact cells and homogenized scaffolds. To assess function and develop surgical procedures, the tissues were implanted into an acute RPE injury model pig eye and evaluated using optical coherence tomography (OCT), multifocal ERG (mfERG), and histology. Subretinal injection studies in rats demonstrated safety of the implant. Biodegradability and biocompatibility data from a pig model demonstrated that PLGA scaffold is safe, with the added benefit of being resorbed by the body over time, leaving no foreign material in the eye. We confirmed that biodegradable substrates provide suitable support for RPE maturation and transplantation.