Cell and Animal Models used for Retinal Stem Cell Research

There are at least 100 million photoreceptors in the human retina and many more cells relaying visual information and providing metabolic support. The pathophysiology of degenerative diseases of the retina such as age-related macular degeneration (AMD), retinitis pigmentosa (RP), and glaucoma involves progressive loss of cell types necessary for vision (photoreceptors, ganglion cells) as well as inadequate trophic support from neighbor cell types (retinal pigmented epithelial cells (RPE), endothelial cells). A cell delivery approach has promise for restoring vision in patients who otherwise have a poor prognosis. Recent strides in the field allowed retinal cell differentiation from a multitude of sources, including but not limited to embryonic stem cells (ESC), adult tissue-derived stem cells (SC), induced pluripotent stem cells (iPSC) [1], retinal progenitor cells (RPC), and Muller cells [2], with excitement for gene-edited autologous stem cell therapy in the near future [3]. Mature RPE cells, photoreceptors, and ganglion cells have also been used in both animals and humans with very promising results. This chapter will provide a brief overview on the types of cells used in retinal cell therapy research and a summary of recent accomplishments.