Cell transplants 'restore sight' in mice

Thursday Nov 9 20:36 AEDT
British scientists say they have used cell transplants to restore vision to
blind mice, raising hopes the development could one day help people.

The mice, which had eye damage similar to that seen in many human eye
diseases, were able to see again after scientists transplanted immature
retinal stem cells into their eyes, the BBC reported.

UK experts described the research as "stunning".

"This is a stunning piece of research that may in the distant future may
lead to transplants in humans to relieve blindness," said Professor Andrew
Dick University of Bristol.

If the results can be translated to treat humans, it could help people
suffering from a broad range of eye conditions ranging from age-related
macular degeneration to diabetes.

In the study involving the mice, scientists took cells from mice aged three
to five days - the stage when the retina is about to be formed.

The cells were then transplanted into the retinas of the blind mice where
they implanted and connected with existing cells in the eye, restoring some
sight to the mice.

Tests showed that the mice's pupils responded to light and that there was
activity in the optical nerve, showing signals were being sent to the brain.

The study was funded by the Medical Research Council and involved scientists
from the University College London Institutes of Ophthalmology and Child
Health and Moorfields Eye Hospital.

"Remarkably, we found that the mature retina, previously believed to have no
capacity for repair, is in fact able to support the development of new
functional photoreceptors," said Dr Jane Sowden, one of the study's leaders.

Photoreceptors are a special type of nerve cell that are necessary for
sight.

To replicate the result in humans, stem cells would have to be taken from a
foetus during the second trimester of pregnancy.

But Dr Robert MacLaren, a specialist at Moorfields Eye Hospital who worked
on the research, said they did not want to go down that route.

He said the aim now would be to look at adult stem cells to see if they
could be genetically altered to behave like the mouse retinal cells, the BBC
reported.