Seeing Anew

University of Toronto researchers have shown that human retinal stem cells transplanted into the eyes of mice and chicks can successfully regenerate – and this knowledge may one day help treat eye diseases such as retinitis pigmentosa and macular degeneration.

After transplantation, the human stem cells developed into photoreceptor cells (which detect light) and retinal pigment epithelial cells (which bounce light and images back onto the retina). “We transplanted them 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 Derek van der Kooy in medical genetics and microbiology.

The pair collaborated with Jules Gonin of Hospital Ophtalmique in Switzerland. “When the animals’ eyes fully developed, the human cells survived, migrated into the sensory part of the eye and formed the correct cells.”