Retinal stem cells can regenerate after transplant

U of T researchers work with human retinal cells

University of Toronto researchers have shown that human retinal stem cells transplanted into the eyes of mice and chicks can successfully regenerate. The research, published in the Oct. 19 issue of The Proceedings of the National Academy of Sciences, documents the development of transplanted human retinal stem cells into light-sensing photoreceptor cells and retinal pigment epithelial (RPE) cells, the cells which bounce light and images back onto the retina.

“We transplanted the cells early in the animals’ development when all the nutrients and signals they needed for differentiation were still there,” says lead author Brenda Coles, a U of T laboratory technician working under the supervision of Professor Derek van der Kooy in the Department of Medical Genetics and Microbiology. “When their eyes fully developed, the human cells survived, migrated into the sensory part of the eye and formed the correct cells.”

The research has implications for future treatment of degenerative eye diseases such as retinitis pigmentosa and macular degeneration but that’s still a long way off, says Coles. She, van der Kooy and their colleagues are now exploring whether retinal stem cells from healthy mice continue to develop into photoreceptor cells and RPE cells when transplanted to mice with diseased eyes. “We’re starting with mice to see if they can overcome the genetics involved in disease,” says Coles. “The eye itself is telling the stem cells what to do, so when we go to a disease model, it is important to know what those signals from the eye are so we can inhibit them or protect the cells.”

The other researchers involved in this study are U of T’s Prof. Roderick McInnes, and post-doctoral fellow Tomoyuki Inoue, Department of Medical Genetics and Microbiology; Brigitte Angenieux and Yvan Arsenijevic, Hopital Ophtalmique Jules Gonin, Lausanne, Switzerland; and Katia Del Rio-Tsonis, Miami University, Ohio.