Joint Centers of Excellence Program

Biomaterial delivery of novel primitive retinal stem cells to treat retinopathy

Age-related macular degeneration (AMD) is the leading cause of blindness in developed countries, affecting over 30 million people worldwide, and Stargardt’s macular dystrophy is the most common form of pediatric retinal degeneration. Both the common, dry form of advanced AMD and Stargardt’s result from the degeneration of the retinal pigmented epithelium (RPE), the cell layer surrounding the retina that provides trophic and structural support to photoreceptors. Despite the prevalence of AMD, these diseases are currently untreatable. In late stages of these diseases, RPE degeneration causes photoreceptor degeneration, so the ideal therapy would replace both RPE and photoreceptors. Replacing RPE will only support surviving photoreceptors; if few remain, this has little effect on vision. Conversely, replacing only photoreceptors would not be effective in the long term, as they require functional RPE to survive. Though transplantation of embryonic stem (ES) cell-derived RPE has advanced to clinical trials and transplantation of retinal progenitors has been shown to replace photoreceptors, no study has yet demonstrated simultaneous replacement of both RPE and photoreceptors. Further, the recent development of injectable hydrogels to improve transplant survival and distribution across the retina promises to enhance their efficacy. Here, we propose to develop a novel approach that combines human ES cell-derived primitive retinal stem cells (hpRSCs), which can differentiate into both RPE and photoreceptors, with a biomaterial delivery system.