Cell-Based Neuroprotection of Retinal Ganglion Cells in Animal Models of Optic Neuropathies

SIMPLE SUMMARY: Progressive loss of retinal ganglion cells in glaucoma and other optic neuropathies results in visual deterioration and eventual blindness. Treatment options for these conditions are limited. In this review, we summarize preclinical work that has demonstrated significant attenuation of ganglion cell loss after intraocular transplantations of a variety of cell types. We also discuss studies aimed at improving the outcome of cell-based neuroprotective approaches by using cells with a forced expression of neurotrophic factors or by employing combinatorial cell-based neuroprotective strategies. ABSTRACT: Retinal ganglion cells (RGCs) comprise a heterogenous group of projection neurons that transmit visual information from the retina to the brain. Progressive degeneration of these cells, as it occurs in inflammatory, ischemic, traumatic or glaucomatous optic neuropathies, results in visual deterioration and is among the leading causes of irreversible blindness. Treatment options for these diseases are limited. Neuroprotective approaches aim to slow down and eventually halt the loss of ganglion cells in these disorders. In this review, we have summarized preclinical studies that have evaluated the efficacy of cell-based neuroprotective treatment strategies to rescue retinal ganglion cells from cell death. Intraocular transplantations of diverse genetically nonmodified cell types or cells engineered to overexpress neurotrophic factors have been demonstrated to result in significant attenuation of ganglion cell loss in animal models of different optic neuropathies. Cell-based combinatorial neuroprotective approaches represent a potential strategy to further increase the survival rates of retinal ganglion cells. However, data about the long-term impact of the different cell-based treatment strategies on retinal ganglion cell survival and detailed analyses of potential adverse effects of a sustained intraocular delivery of neurotrophic factors on retina structure and function are limited, making it difficult to assess their therapeutic potential.