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| The necessary cells can be found in the back of everyone's eyes |
Cells taken from the donated eyes of dead people may be able to
give sight to the blind, researchers suggest.
Tests in rats, reported in Stem Cells Translational Medicine,
showed the human cells could restore some vision to completely blind rats.
The team at University College London said similar results in
humans would improve quality of life, but would not give enough vision to read.
Human trials should begin within three years.
Donated corneas are already used to improve some people's sight,
but the team at the Institute for Ophthalmology, at UCL, extracted a special
kind of cell from the back of the eye.
These Muller glia cells are a type of adult stem cell capable of
transforming into the specialised cells in the back of the eye and may be
useful for treating a wide range of sight disorders.
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“This interesting study shows that Muller glial cells are another
viable avenue of exploration for cell therapy in retinal diseases,” Dr Paul
Colville-Nash Medical Research Council said.
In the laboratory, these cells were chemically charmed into
becoming rod cells which detect light in the retina.
Injecting the rods into the backs of the eyes of completely blind
rats partially restored their vision.
Brain scans showed that 50% of the electrical signals between the
eye and the brain were recovered by the treatment.
One of the researchers, Prof Astrid Limb, told the BBC what such a
change would mean in people: "They probably wouldn't be able to read, but
they could move around and detect a table in a room.
"They would be able to identify a kettle and cup to make a
cup of tea. Their quality of life would be so much better, even if they could
not read or watch TV."
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| The different layers of the retina, with the light-sensing rods and cones at the top |
The cells might be able to help patients with disorders such as
macular degeneration or retinitis pigmentosa.
Human stem cell trials are already taking place using material
taken from embryos.
However, this is ethically charged and takes several months to
prepare the cells. The Muller glia cells can be ready within a week.
Prof Limb commented: "They are more easily sourceable and
very easy to handle in the lab so from that perspective they're better, but
they do express antigens that could induce an immune response."
It means the donated cells could be rejected like an organ
transplant.
The next step is to prepare the cells as a clinical grade
treatment in order for human trials to begin.
The researchers believe it could take three years before such a
trial takes place.
Dr Paul Colville-Nash, the regenerative medicine programme manager
at the Medical Research Council, which funded the study, said: "This
interesting study shows that Muller glial cells are another viable avenue of
exploration for cell therapy in retinal diseases.
"It's not clear yet which approach will be most effective
when these experimental techniques enter human trials, which is why it is
important to progress research across all avenues in pursuit of a cure for
sight loss."
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