Success in Cell Therapy for Degenerative Blindness

There are signs of progress in the use of cell therapies to restore vision. A small trial involving patients suffering from forms of degenerative blindness caused by loss of retinal cells is reporting better results than expected:

The study involved patients suffering from age-related macular degeneration and Stargardt's macular dystrophy, the two leading causes of adult and juvenile blindness in the developed world. The diseases destroy a person's central vision. Working with Advanced Cell Technology Inc. [researchers] took human embryonic stem cells and turned them into the kind of cells that are killed by these diseases - retinal pigment epithelial cells. Then, they infused between 50,000 and 150,000 cells into the retinas of the patients. "What we did is put them into patients who have a disease where those particular cells are dying; and we replaced those dying tissues with new tissue that's derived from these stem cells. In a way it's a retinal transplant."

No one expected the cells to help any of these patients see better, because the study was designed mostly just to see if doing this was safe. Researchers were concerned the cells could destroy whatever vision was left or lead to tumors in the volunteers' eyes. So [they] picked patients whose eyes were so far gone that they weren't risking losing any vision. That also meant that there was little hope the cells could help either.

Surprisingly, many of the patients did start to see better. Ten of the 18 patients can see significantly better. One got worse, but the other seven either got better or didn't lose any more vision. The researchers stress that the findings must be considered preliminary because the number of patients treated was relatively small and they have only been followed for an average of less than two years. But the findings are quite promising. The patients had lost so much vision that there was no expectation that they could benefit.



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