Dr. Stephen Tsang, from the Columbia University Medical Center, said researchers had “never seen this type of improvement in retinal function in mouse models of RP”.
In the stem cell study, researchers used induced pluripotent stem (iPS) cell grafts to restore visual function. Like embryonic stem cells, iPS cells are capable of developing into any cell type. In this case, they were derived from adult human skin cells and injected underneath the mice retinas.
The iPS cells assimilated into the host retina and were found to express markers specific to retinal pigmented epithelium, showing they had the potential to develop into functional retinal cells. In theory, iPS cell transplants could also be used to treat age-related macular degeneration, Dr. Tsang said.
In the second study, researchers tested whether gene therapy could be used to improve photoreceptor survival in mice with RP caused by a genetic called phosphodiesterase-alpha – a common form of the disease in humans. Photoreceptor cells were later found in the treated eyes but not the untreated eyes. More importantly, the treated eyes showed functional visual responses, while the untreated eyes had lost all vision.