[Nfbf-l] From BBCC News: Totally blind mice have had their sight restored by injections of light-sensing cells

[Alan Dicey]

>From BBC News, 1/6/2013.
Totally blind mice have had their sight restored by injections of 
light-sensing cells into the eye, UK researchers report.

The team in Oxford said their studies closely resemble the treatments that 
would be needed in people with degenerative eye disease.
Similar results have already been achieved with night-blind mice.
Experts said the field was advancing rapidly, but there were still questions 
about the quality of vision restored.
Patients with retinitis pigmentosa gradually lose light-sensing cells from 
the retina and can become blind.
It's the first proof that you can take a completely blind mouse, put the 
cells in and reconstruct the entire light-sensitive layer"
Prof Robert MacLaren University of Oxford
The research team, at the University of Oxford, used mice with a complete 
lack of light-sensing photoreceptor cells in their retinas. The mice were 
unable to tell the difference between light and dark.
Reconstruction
They injected "precursor" cells which will develop into the building blocks 
of a retina once inside the eye. Two weeks after the injections a retina had 
formed, according to the findings presented in the Proceedings of the 
National Academy of Sciences journal.
Prof Robert MacLaren said: "We have recreated the whole structure, basically 
it's the first proof that you can take a completely blind mouse, put the 
cells in and reconstruct the entire light-sensitive layer."
Previous studies have achieved similar results with mice that had a 
partially degenerated retina. Prof MacLaren said this was like "restoring a 
whole computer screen rather than repairing individual pixels".
The mice were tested to see if they fled being in a bright area, if their 
pupils constricted in response to light and had their brain scanned to see 
if visual information was being processed by the mind.
Vision
Prof Pete Coffee, from the Institute of Ophthalmology at University College 
London, said the findings were important as they looked at the "most 
clinically relevant and severe case" of blindness.
This is probably what you would need to do to restore sight in a patient 
that has lost their vision," he said.
However, he said this and similar studies needed to show how good the 
recovered vision was as brain scans and tests of light sensitivity were not 
enough.
He said: "Can they tell the difference between a nasty animal and something 
to eat?"
Prof Robin Ali published research in the journal Nature showing that 
transplanting cells could restore vision in night-blind mice and then showed 
the same technique worked in a range of mice with degenerated retinas.
He said: "These papers demonstrate that it is possible to transplant 
photoreceptor cells into a range of mice even with a severe level of 
degeneration.
"I think it's great that another group is showing the utility of 
photoreceptor transplantation."
Researchers are already trialling human embryonic stem cells, at Moorfields 
Eye Hospital, in patients with Stargardt's disease. Early results suggest 
the technique is safe but reliable results will take several years.
Retinal chips or bionic eyes are also being trailed in patients with 
retinitis pigmentosa.

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