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Friday, June 25, 2010

great news for vi persons

(taken from the internet)
June 18 (Bloomberg) -- Patients blinded in one or both eyes bychemical burns regained their vision after healthy stem cells wereextracted from their eyes and reimplanted, according to a report byItalian researchers at a scientific meeting. The tissue was drawn from the limbus, an area at the junction of thecornea and white part of the eye. It was grown on a fibrous tissue,then layered onto the damaged eyes. The cells grew into healthycorneal tissue, transforming disfigured, opaque eyes into functioningones with normal appearance and color, said researchers led byGraziella Pellegrini of the University of Modena’s Center forRegenerative Medicine. The stem-cell treatment restored sight to more than three- quarters ofthe 112 patients treated, Pellegrini said yesterday in a presentationat the International Society for Stem Cell Research meeting. Thepatients were followed for an average of three years and some for aslong as a decade, Pellegrini said. “The patients, they are happy, even the partial successes,” she saidin an interview at the meeting in San Francisco. “We have a couple ofpatients who were blind in both eyes. Can you imagine for thesepatients the change in their quality of life?” The work was praised by Ivan Schwab, an ophthalmology professor andstem cell researcher at the University of California, Davis, who hastreated patients in clinical trials with a procedure based onPellegrini’s work. While his patients improved for a time, thebenefits didn’t endure, he said in a June 15 telephone interview.Pellegrini’s patients appear to have long-term improvement, he said. “The powerful part of her work is she has such long-term follow-up,”Schwab said. Many of the patients she treated had been blind for years as result oftissue and blood vessels growing over damaged parts of the eye. Somehad been through failed surgeries and alternative treatments.Pellegrini estimated 1,000 to 2,000 patients in Europe suffer fromburns with chemicals such as bleach or industrial solvents and maybenefit from the procedure. The key to success is to be certain that when the stem cells extractedfrom the limbus are grown in culture they have the right mix of stemcells and the differentiated cells that form the corneal tissue,Pellegrini said. If there are too few stem cells in the transplant,the improvement won’t last because there will be no reservoir to formthe new corneal cells needed with the normal recycling of cells overtime, she said. The procedure succeeded after a single transplant in 69 percent ofcases. A second procedure was performed on some patients, boosting thesuccess rate to 77 percent, she said. The procedure was deemed apartial success in 13 percent of cases and a failure in 10 percent,she said. Depending on the depth of the injury, some patients regained sight inas little as two months, Pellegrini said. Others with deeper injuriesneeded a second procedure and waited a year before sight was restored,she said. The applications of the work may extend to other organs, Schwab said. “This is bigger than just the surface of the eye,” he said. “She maybe making a model for how to regenerate livers or other organs.”