Endogenous retinal cell therapy by Dr. Chris Moen 5-18-2013:
While stem cells have been highly touted due to their ability to differentiate into RPE and photoreceptors, these cells would require transplantation or injection to reach the areas of the retina depleted by degeneration. However, cells in other layers of the retina, most notably ganglion cells, have been shown to have the capacity to act in a similar fashion. Inducing these cells to differentiate into RPE and photoreceptors would theoretically enable the restoration of visual function without transplantation. Dr. Dong Feng Chen at Schepens Eye Institute at Harvard University has published promising research in this field. They have identified naturally-occurring chemicals, glutamate and aminoadipate, which can induce the Muller cells in the retina to demonstrate progenitor cell behavior, dividing and differentiating into more highly specific cells. By adding aminoadipate to Muller cells in culture then injecting these into the subretinal space of healthy mice, they not only demonstrated the differentiation into photoreceptor cells but also noted the migration of these new cells into areas of the retina in need of healthy cells. Further research will involve testing this technique in animals with specific retinal degenerative diseases. Similar projects are ongoing at Notre Dame, the University of California San Diego, and the University of Washington. Success of any of these projects would likely enable the retina to regenerate itself without the surgical procedures involved with retinal cell transplantation, however no clinical trials are scheduled at this time.