Stem cell cure for blindness
Posted on: 11:08 PM IST Jun 06, 2007
London: British scientists plan to use stem cells to cure a common form of blindness, with the first patients receiving test treatment in five years.
The pioneering project launched on Tuesday, aims to repair damaged retinas with cells derived from human embryonic stem cells. Its backers say it involves simple surgery that could one day become as routine as cataract operations.They believe the technique is capable of restoring vision in the vast majority of patients with age-related macular degeneration (AMD), a leading cause of blindness among the elderly that afflicts around 14 million people in Europe.Some drugs, like Genentech Inc.'s Lucentis, can help the one in 10 patients with so-called "wet" AMD and US biotech firm Advanced Cell Technology is looking at stem cells in other eye conditions. But there is no treatment for the 90 per cent with "dry" AMD.AMD is caused by faulty retinal pigment epithelial (RPE) cells, which form a supporting carpet under the light-sensitive rods and cones in the retina.The new procedure will generate replacement RPE cells from stem cells in the lab, with surgeons then injecting a small patch of new cells, measuring four by six millimeters, back into the eye.PAGE_BREAKUS DonorThe London Project to Cure AMD brings together scientists from University College London (UCL), Moorfields Eye Hospital in London and the University of Sheffield.It has been made possible by a £4 million ($8 million) donation from an anonymous US donor, who the project's leaders said, had become frustrated by US curbs on stem cell work.Embryonic stem cells are the ultimate master cells of the body, giving rise to all of the tissues and organs. Their use is controversial because many people oppose embryo destruction, although Britain has encouraged such research.Surgeons at Moorfields have already restored the vision of a few patients using cells harvested from their own eyes, which were moved to a new site. But this process is complicated and only a small number of cells can be moved, limiting its use.By injecting RPE cells derived from stem cells instead, Dr Lyndon Da Cruz of Moorfields hopes the operation can be reduced to a simple 45-minute procedure under local anesthetic."If it hasn't become routine in about 10 years it would mean we haven't succeeded," he told reporters. "It has to be something that's available to large numbers of people."Similar tests on rats have already proved highly effective.Pete Coffey of UCL, the director of the project, said he was confident the procedure would work in humans but the team needed to ensure the safety and quality of batches of cells, which would take time."The goal is within five years to have a cohort of 10 or 12 patients to put the cells into," he said.The project, which is non-commercial, was welcomed by patient support groups. Alistair Fielder of the eye research charity Fight for Sight said it represented a real chance to tackle a hitherto untreatable condition.