Translating retinal stem cells

Published on December 28, 2016   22 min
My name is Michael Young from the Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Stem Cell Institute. I'm in the Department of Ophthalmology at Harvard Medical School, talking to you today about translating retinal stem cells.
So the disease that we focus on in my laboratory for treating with stem cells is retinitis pigmentosa. The retinitis pigmentosa are a group of hereditary diseases that cause retinal degeneration and there are a lot of different diseases, there are actually hundreds of different mutations that can lead to retinitis pigmentosa, but the common feature is that rod photoreceptors typically die first. And again, there is no effective treatment at present for this disease.
What is new in this field is that there are a host of new regenerative and neuroprotective strategies available to treat retinitis pigmentosa. So these include gene therapy, neuroprotection with growth factors, implants such as prosthetic chips that are being devised to integrate with the visual system in a variety of different ways, a brand new field called optogenetics in which non-photosensitive cells are induced to become photosensitive through gene transfer technology; And what I'm going to talk to you today about, principally, is cell replacement. I'm really talking mostly about replacing rods and cones.
So the diseased retina has been thought of as a structure that can be repaired for many years, but most of these attempts have failed. But these retinal transplants we'll call them, have been performed without the use of stem cells, so with embryonic tissue, fetal tissue, even adult tissue but not expanded stem cells; And these grafts have failed principally because they did not connect to the host. So what's new is that stem cells can overcome this barrier and integrate with the host. But this brings up a new challenge and that is to harness the plasticity of these cells, and that means differentiation - getting these cells to become the type of cells that we really want them to become. And in the case of the work I'm talking about today, that really is rod photoreceptor.