FRIDAY, Oct. 29 (HealthDayNews) -- Human retinal stem cells can regenerate when implanted into the eyes of chicks and mice, says a University of Toronto study.

After being transplanted into the animals, the human retinal stem cells developed into light-sensing photoreceptor cells and retinal pigment epithelial cells (RPE), which bounce images and light back onto the retina.

This research may eventually help scientists develop treatments for degenerative eye diseases such as macular degeneration and retinitis pigmentosa, the researchers said.

"We transplanted the cells early in the animals' development when all the nutrients and signals they needed for differentiation were still there," study author Brenda Cole, a laboratory technician in the department of medical genetics and microbiology, said in a prepared statement.

"When their eyes fully developed, the human cells survived, migrated into the sensory part of the eye and formed the correct cells," Cole said.

The study appeared in a recent issue of the Proceedings of the National Academy of Sciences.

The next step in this line of research is to transplant retinal stem cells from healthy mice into mice with diseased eyes to see if the stem cells develop into photoreceptor and RPE cells.

"We're starting with mice to see if they can overcome the genetics involved in disease. 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," Cole said.

More information

The U.S. National Eye Institute has more about eye disease.