UW Stem Cell Researchers Building a 'Retinal Patch' to Restore Vision
Madison, Wisconsin – A team led by a University of Wisconsin School of Medicine and Public Health stem-cell scientist and ophthalmologist is beginning work on a patch made of induced pluripotent stem cells (iPSCs) to help restore vision to people whose retinas have been damaged by conditions such as retinitis pigmentosa and age-related macular degeneration.
Dr. David Gamm, director of the McPherson Eye Research Institute and associate professor of ophthalmology and visual sciences at the UW School of Medicine and Public Health, and collaborators will begin developing the stem-cell therapy, thanks to a $900,000 grant from the Foundation Fighting Blindness.
Gamm, a pioneer in retinal stem-cell research, says that a two-layered patch of cells to replace damaged retinal tissue could be the best strategy for reconstructing the outer retina when multiple cell types have succumbed to disease. Gamm’s lab has succeeded in using stem-cell technology to turn skin and blood cells into retinal cells.
“The continuing challenge has been to get the transplanted cells to survive the hostile conditions of the diseased retina, arrange themselves appropriately, and make the necessary connections to restore vision,” says Gamm. “I believe we have a plan that will make progress toward that goal.”
Gamm’s collaborators include Dr. James Thomson of the Morgridge Institute for Research, Dr. Derek Hei of the UW-Madison Waisman Center and Dr. Dennis Clegg of the University of California-Santa Barbara.
The plan is to create a two-layered patch of cells consisting of photoreceptor precursors, which can develop into vision-enabling rods and cones, and mature retinal pigment epithelial (RPE) cells, which provide waste disposal and nutrition for the photoreceptors.
A thin plastic film developed by Clegg’s group will serve as a structural backbone for the patch. A biodegradable gel will protect the cells and bring the layers together.
“In many retinal diseases, both RPE and photoreceptors are lost and need to be replaced,” says Gamm. “We don’t want to transplant an unstructured mix of RPE and photoreceptors, because they are not likely to integrate and function properly, especially in a retina that’s suffered significant degeneration. Our patch - a pre-formed structure that better resembles natural retina - should give the cells a better chance of surviving and providing vision.”
Gamm’s group is working with the Madison-based company Cellular Dynamics International as well as the Waisman Biomanufacturing Facility, who are creating lines of iPSCs from “super donors” - people whose cells and tissues provide a beneficial immune match for a significant percentage of the general public.
When properly matched with the recipient, the cells are less likely to be rejected. Their collective goal is to have an “off-the-shelf” iPSC inventory that can be used to create a patch therapy for virtually any patient, regardless of their disease or immune-system profile.
While iPSCs can be derived from each patient on a case-by-case basis, Gamm says the super-donor solution is technically simpler, less costly and may work just as effectively. His research will help bear out this approach’s feasibility and benefits.
Gamm acknowledges that he and his colleagues will be learning as much from the research process as they will from its final outcomes
“We’re pushing the envelope by transplanting multiple cell types. But along the way we will seek to answer several important questions: Can we make cells that align correctly with one another? Do they make connections with other cells? What is the best way to transplant them, keep them healthy, and promote their integration within a diseased retina?
“It’s not an easy task, but neither was making those first retinal cells from iPSC back in 2008. We reached our goals then, and I am confident that the field will keep moving forward.”
Date Published: 04/12/2013