Cell therapy for retinitis pigmentosa: From rats to pigs

Retinitis pigmentosa (RP) is a leading cause of blindness worldwide and lacks effective clinical treatment. Stem cell-based therapy offers a novel experimental therapeutic approach, based on the strategy that transplanted progenitor cells can replace or rescue damaged photoreceptor cells. However, many factors remain to be determined, for example, what is the optimal time to choose for targeting the host tissue during the progression of the degeneration, what the characteristics and potential capacities in different stem cells, do stem cells differentiate into functional daughter cells, and to what degree can host retinal function be restored? We have used Royal College of Surgeons rats and light-induced retinal degeneration minipigs as animal models of retinitis pigmentosa to study the effectiveness of cell transplant therapies and the functional capacity of the host retina. Stem cells from rat retina and bone marrow, neonatal pig, and human fetal retina have been investigated to find the proper donor cells. The dedifferentiation and then redifferentiation of Müller cells following retinal stem cell transplantation may contribute to host visual function and presents a promising line of research.