RESTORING SIGHT to the blind may just have moved from the realms of miracle to medical reality. Researchers in Britain have successfully renewed a level of sight in visually impaired mice, opening the possibility that the same can be achieved in humans.
The University College London researchers transplanted immature vision cells directly into the mouse retina.
Within weeks the cells began to integrate into the retina and the researchers, led by Prof Robin Ali in the university’s Institute of Ophthalmology, were able to show that vision began to return to the mice.
The cells involved – known as photoreceptors – are lost in very common degenerative diseases such as retinitis pigmentosa, age-related macular degeneration and diabetic retinopathy, said Anna Moran, external affairs manager at Irish medical charity Fighting Blindness. At least 100,000 people here are affected by these conditions.
Prof Ali receives funding from Fighting Blindness and is also the body’s associate director of research. This work was funded directly by the UK Medical Research Council and details are published this morning in the journal Nature.
The eye has two types of photoreceptors: rod cells and cone cells. The UCL team collected immature rod photoreceptor cells from healthy donor mice and transplanted them into the retinas of the vision-impaired mice.
After four to six weeks the transplanted cells had formed connections to the optic nerve and were working almost as well as rod cells in healthy mice, the researchers found.
The research team was able to confirm vision had been restored by placing the mice in a dimly lit maze. Mice with transplanted cells were able to find a raised platform much more quickly than mice without the transplanted cells.
“We have shown for the first time that transplanted photoreceptor cells can integrate successfully with the existing retinal circuitry and truly improve vision,” Prof Ali said.
Researchers were taken aback by the results. “It is restoring visual function and to a much higher degree than they expected,” Ms Moran said.
“Fighting Blindness has been supporting vision research for 30 years and this is probably the most important finding in that time.”
It will be some years before human trials can begin, but as a next step Prof Ali hopes to use embryonic stem cells to produce transplant tissues to renew damaged retinas.
