The breakthrough holds out the hope of a cure in the future for age-related macular degeneration
Scientists have improved the sight of two people who were almost blind by injecting their eyes with stem cells from embryos.
The two women, both registered as blind, saw their vision improve in a matter of weeks after being given the embryo-derived cells in the US safety trial.
The breakthrough holds out the hope of a cure in the future for age-related macular degeneration, which currently affects some 500,000 people in Britain.
The results, published this week in The Lancet, provide a major boost for the field of stem cell reseach.
Professor Daniel Brison, of the North West Embryonic Stem Cell Centre in Manchester, said: “This is a very exciting moment for embryonic stem cell therapies.
This is the first peer-reviewed scientific report showing that cells derived from human embryonic stem cells can be transplanted safely into a patient with no sign of complications.
“Although the study is limited to safety considerations, very small in scope, and at a very early stage, this is nonetheless a ground breaking moment for embryonic stem cell therapies.”
Meanwhile, a British man has become the first European to be treated with embryonic stem cells, at the Moorfield Eye Hospital in London, which is running a parallel trial.
Both the women in the US study arm suffer from forms of macular degeneration – worsening central vision – that are caused by retinal cells dying.
The first, in her 70s, suffers from dry age-related macular degeneration, the leading cause of blindness in the West. She went from being able to read 21 letters on a sight test chart to 28.
The second, in her 50s, suffers from Stargardt’s disease, the most common form of macular degeneration in younger patients. She went from only being able to detect hand movements, to being able to see finger movements and better. Both received the stem cell treatment last July.
Researchers at the Jules Stein Eye Institute at the University of California, Los Angeles, also found no safety concerns with the two patients, four months after they were treated.
Each patient had a single eye injected with about 50,000 retinal pigment epithelium (RPE) cells that had been derived from embryonic stem cells. In this way, vision in one eye could be compared against vision in the other.
Dry age-related macular degeneration is caused by death of RPE cells in the retina and subsequent loss of light receptive rod and cone cells beneath them. In Stargardt’s, the same cells are lost, but this is caused by a genetic defect that starts to show in teenagers.
The theory is that the new RPE cells, developed by US stem cell company Advanced Cell Technology (ACT), will help repopulate the epithelial layer, which will improve the health of the underlying rods and cones.
Dr Robert Lanza, chief scientific officer at ACT and one of the study authors, commented: “Despite the progressive nature of these conditions, the vision of both patients appears to have improved after transplantation of the cells, even at the lower dosage.
“This is particularly important, since the ultimate goal of this therapy will be to treat patients earlier in the course of the disease where more significant results might potentially be expected.”
He and his co-authors emphasised that the study, which will be into 24 patients, was currently only “designed to test the safety and tolerability” of the technique.
Meanwhile, the first of 12 volunteers in the European arm has been injected with the stem cell derived RPE cells.
Marcus Hilton, 34, from Wakefield in West Yorkshire, received the dose in his right eye at the Moorfield on Friday under general anaesthetic. He is just the third person worldwide to receive the cells to help vision.
Mr Hilton, who runs bars in the town, said: “I was diagnosed with Stargardt’s at 10 and I have pretty poor central vision.
“Nobody had been able to do anything about it until I was contacted last November by Moorfield.”
He said it was too early for there to have been any effect, but he would be returning to the hospital in March for an assessment.
He said of the US findings: “I’m over the moon they have had early results in America showing this treatment could work.
“It could change many people’s lives – to have some sight restored would be a dream come true.”
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