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| Stem-cell Treatment Helps Restore Eye-sight |
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| Animals | |
| Vendredi, 13 Juin 2008 08:00 | |
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There are no translations available. Source: Telegraph.co.uk  By Richard Gray Six blind patients have had their eye-sight restored after undergoing pioneering stem cell transplants.
Researchers at Moorfields Eye Hospital in London treated the patients as part of a clinical trial on patients who have lost their sight from chemical accidents or a rare genetic disease. Using stem cells from tissue donors, surgeons grew the cells in the laboratory before transplanting them onto the patients' eyes. Dr Julie Daniels, who is leading the research team, will present the results at a conference on regenerative medicine being held in Welwyn Garden City, Hertfordshire, today. She said: "Before the surgery the patients were barely able to recognise when someone was waving a hand in front of their face but we have restored their vision to the point they can read three to four lines down the eye chart." Nineteen patients have now received the treatment, known as limbal stem cell therapy, at Moorfields Eye Hospital. The patients were chemical burn victims or sufferers of a rare genetic disease known as aniridia. They had injuries to the limbal cells in their eyes, which are under the eye lid and maintain the transparent layer on the outside of the cornea. Dr Daniels said: "Their cornea becomes opaque, blood vessels grow across it and their eyes become inflamed and they can't see anymore. It is very painful. "By replacing the limbal stem cells, the cornea begins to clear up as the cells are replaced with the healthy transparent layer again. "We can't restore sight completely yet as the material we are growing the stem cells on is slightly opaque, but patients are certainly reporting an improvement." Ten patients were given the transplant 32 months ago and six of those have showed remarkable recovery. The remaining nine patients were treated eight months ago and are still to have their recovery assessed. Scientists at Moorfields Eye Hospital are also hoping to use stem cells to treat other causes of blindness by creating small patches of retina cells, which detect light at the back of the eye. The Royal National Institute for the Blind (RNIB) welcomed the results of the limbal cell trial. Barbara McLaughlin, campaigns manager at RNIB, said: "Anything that can restore sight to people who thought they had irretrievably lost their eyesight is a major step forward. "This research is very exciting, but we would caution that these treatments can take a significant amount of time and research before they can be widely used." More than 250,000 people suffer injuries to their eyes every year as a result of accidents, although only a small proportion of these are due to burns. Hays was taking Maggie Mae to acupuncture treatments and learned of the stem-cell option during one of those appointments. "If this is something that works, it could help many people and many animals someday," Hays said. "I'm just thrilled to think [Maggie Mae has] been a part of it." The stem-cell treatment starts with surgery to remove about 50 grams of fat, typically from the dog's abdomen, explained Dr. Jacek de Haan from Affiliated Veterinary Specialists in Maitland. He said all tissue holds some stem cells, and veterinarians use fat because it's typically plentiful and easy to remove. The dogs must be healthy enough to have the surgery, which requires the animals to be put under general anesthesia. Because anesthesia comes with risks, de Haan said dogs with other major health issues -- such as heart disease or kidney failure -- are not good candidates. It's more for dogs that are generally healthy aside from their arthritis. After the fat is removed, it is sent to the California company that has been using it to help horses recover from tendon and other injuries since 2003. Vet-Stem began offering the treatment for dogs with arthritis earlier this year. De Haan said the cost is about $2,500. The company takes the fat sample, isolates the stem cells and returns the solution to the veterinarian, who then injects arthritic joints. There are no guarantees that the dogs will get relief, but many owners report seeing improvements within a month of the treatment, de Haan said. He has treated seven local dogs so far. "Usually, activity level improves, they're able to run more and be more active. If they weren't able to jump on furniture before, they are about to do it afterward," he said. The treatment -- because it involves removing and replacing cells from the same animal -- is not controversial and not regulated by the government, said Dr. Julie Ryan Johnson, a veterinarian and vice president at Vet-Stem. That also means it hasn't been tested in large-scale, rigorous studies before it hit the market. But one study sponsored by the company compared dogs that were given stem cells with those that received placebo injections. The researchers found that the stem-cell group had significant improvement in their walking and trotting. The animals also had less pain when their joints were manipulated and had greater range of motion. What exactly are the stem cells doing? Short answer: No one knows. Johnson said X-rays of the animals' arthritic joints don't show marked differences after treatment, suggesting that the stem cells are working in subtle ways. "They may be signaling other cells to come in and do different things -- to reduce pain and inflammation or build new tissue," Johnson said. "The X-rays may not look any better, but there's definitely something going on there." Robyn Shelton can be reached at 407-420-5487 or Cette adresse email est protégée contre les robots des spammeurs, vous devez activer Javascript pour la voir. .
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