Concise review: toward stem cell-based therapies for retinal neurodegenerative diseases

Loss of sight due to irreversible retinal neurodegeneration imposes a significant disease burden on both patients and society. Glaucoma and age-related macular degeneration are the commonest neurodegenerative blinding diseases in the developed world, and both are becoming increasingly prevalent as populations age. Our heavy reliance on our sense of sight means that visual loss often severely restricts day-to-day life, making it difficult to function without additional support. Visual impairment also limits employment possibilities, adding to the economic burden. Current therapies for many degenerative retinopathies are limited in their efficacy, often treating the effects of disease rather than the underlying causes. Consequently, the development of novel adjunctive neuroprotective and neuroregenerative treatments are important goals. Evidence from animal models suggests that stem cells could be useful as part of novel new treatment strategies for eye disease. The accessibility of the eye and extensive repertoire of available surgical techniques may facilitate the translation of stem cell-based therapies, for example, via transplantation, to the retina more rapidly than to other parts of the central nervous system. This concise review will examine how cell therapies are being applied experimentally for neuroregenerative and neuroprotective treatment of currently incurable degenerative retinal diseases. Furthermore, recent progress toward clinical translation of such therapies will be highlighted.