The potential of stem cell research for the treatment of neuronal damage in glaucoma.

Stem cell research offers a wide variety of approaches for the advancement of our understanding of basic mechanisms of neurodegeneration and tissue regeneration and for the discovery and development of new therapeutic strategies to prevent and restore neuronal cell loss. Similar to most other regions of our central nervous system, degenerative diseases of the retina lead to the loss of neurons, which are not replaced. Recent work in animals has provided proof-of-concept evidence for the restoration of photoreceptor cells by cell transplantation and neuronal cell replacement by regeneration from endogenous cell sources. However, efficient therapeutic prevention of neuronal cell loss has not been achieved. Moreover, successful cell replacement of retinal neurons in humans, including that of ganglion cells, remains a major challenge. Future successes in the discovery and translation of neuroprotective drug and gene therapies and of cell-based regenerative therapies will depend on a better understanding of the underlying disease pathomechanisms. Existing stem cell and cell-reprogramming technologies offer the potential to generate human retina cells, to develop specific human-cell-based retina disease models, and to open up novel therapeutic strategies. Further, we might glean substantial knowledge from species that can or cannot regenerate their neuronal retina, in the search for new therapeutic approaches. Thus, stem cell research will pave the way toward clinical translation. In this review, I address some of the major possibilities presently on offer and speculate about the power of stem cell research to gain further insights into the pathomechanisms of retinal neurodegeneration (with special emphasis on glaucoma) and to advance our therapeutic options.