Abstract
Retinal degenerations are significant causes of vision loss. Efforts to stimulate regeneration of retinal neurons from Muller glia have recently been successful for amacrine cells, but not for photoreceptors. Cell replacement using transplantation offers an alternative therapy to potentially restore visual function to individuals who have lost their sight from photoreceptor degeneration. To provide a source of new retinal neurons for cell based therapies, we developed methods to derive retinal progenitors from human ES cells. We have found that the photoreceptors derived from human ES cells can be transplanted to mice with inherited retinal degeneration, and that they restore light response to the animals. We have also recently developed methods to purify the photoreceptors prior to transplantation. These results provide a proof of principle that human ES cells can be useful in cell replacement therapies for retinal degenerations.