Scientists say they've restored the vision of blind mice by introducing light-sensitive cells into their retinas. These are not stem cells, but come from a later stage of cell development when stem cells have already determined what type of cells they will be. In this case we're talking about the rod-and-cone photoreceptors the eye uses to sense light.
"We think this is a major breakthrough because it shows what can be achieved," said study lead researcher Dr. Robert MacLaren, a consultant vitreoretinal surgeon at Moorfields Eye Hospital and a clinician scientist at the University of London, in England.
Scientists have tried to use stem cells before to restore sight, but their efforts failed. Dr. MacLaren believes that timing is crucial to success. He transplanted the photreceptors from newborn mice into the blind mice's retinas (they are looking for a way to use adult stem cells) and the retinas accepted these photoreceptors and made connections to the mice's brains. The mice are receptive to light.
"These cells were transplanted extremely quickly (i.e., 30 minutes out of their normal environment)," MacLaren said. This rapid transfer, plus their positioning in a conducive retinal environment, means that the cells "were able to form quick connections with host cells," he said.
This certainly sounds hopeful. If they can learn how to use adult stem cells they won't need embryonic stem cells.
Dale L. Edwards
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