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In Stem-Cell Transplants, Timing Is Everything

A research study published earlier this week gave a hint that the dream of life-changing stem-cell therapy could soon come true. Cell transplant surgery enabled blind mice to show rudimentary responses to light, a modest step toward sight.

The study may turn out to be extremely important, not just for sight studies, but for the entire field of cell-based therapies, including stem cells.

Stem cells are a promising part of advances in therapy, because they can turn into a variety of cell types. But stem cells may only be useful after they've begun to change into the cell type they're destined to become.


A case in point: If you transplant stem cells into an eye with a damaged retina, nothing happens. But according to new research, if you wait until those cells start turning into specific cells in the retina, and then transplant them, you can restore some vision.

The researchers, who have published their findings in Nature, waited to locate cells that were already destined to become a particular kind of retinal cell called a rod.

When transplanted into a mouse, the new cells took up residence. And when the researchers shined a light into the mouse's eye, the animal's pupil constricted, meaning it was seeing the light.

Understanding the timing of when to transplant the cells -- after they're no longer stem cells, for instance -- may be the key to a variety of new therapies.

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