Human stem cells help blind rats see

Washington: Human embryonic stem cells can partly restore vision in blinded rats, and may offer a source of transplants for people with certain eye diseases, researchers at a US company reported yesterday.

The finding, published in the journal Cloning and Stem Cells, might offer a way to use stem cells that now exist in laboratories, the researchers said.

"We have developed a technology that we hope can be used to treat degenerative eye diseases such as macular degeneration," said Dr Robert Lanza of Advanced Cell Technology in Massachusetts, who led the study.

At the start of the experiment, the researchers had to get the stem cells to generate the desired tissue. Then they transplanted them into the rats. The cells grew normally and did not as is a risk with embryonic cells form tumours, Lanza said. Soon the rats were able to follow lights with their eyes. They had about 70 per cent of the spatial acuity of a normal, healthy rat. When examined, their eyes had grown layers of retinal cells.