Field of Science

Showing posts with label retina. Show all posts
Showing posts with label retina. Show all posts

Embryonic stem cells: can we really restore vision to the blind?


Restoring sight to the blind is, literally, a miracle.  For centuries, men have told stories of miracles in which a blind person suddenly was able to see again.

In modern times, there have been cases of vision restored thanks to corneal transplants and cataract surgery.  These are amazing treatments themselves, and they have become almost routine in the developed world.  But when the cells inside the eye are damaged, there is nothing we can do.

Until now.  In an amazing advance, scientists at Advanced Cell Technology reported this week in The Lancet that they used embryonic stem cells to restore partial vision to 2 patients who were legally blind.  One patient had macular degeneration, a very common but incurable eye disease, and the second had Stargardt disease.  Both diseases are progressive and usually lead to blindness.

Both diseases also affect internal eye cells known as retinal pigment epithelium (RPE) cells.  The research team, led by Robert Lanza, took human embryonic stem cells and coaxed them into becoming RPE cells.  They tested the RPE cells extensively for any signs of contamination by viruses or bacteria, and once they confirmed that the cell cultures were pure, they injected them into the eyes of these first two patients.  (Earlier studies were done in mice and rats before trying the therapy on humans.)

After four months, both patients showed improvements in vision.  This is an amazing result for macular degeneration, which has been, until now, irreversible.  The cells appeared to "take" in both patients, attaching to other cells in the eye and replacing damaged areas.  As Rob Stein and David Brown reported in the Washington Post
"One of them no longer needs a large magnifying glass to read and can reportedly thread a needle. The other has begun to go shopping on her own."
According to the study, neither patient has shown any signs of rejecting the cells.

The Lancet study, which you can read here, was funded entirely by private funds due to U.S. government restrictions on embryonic stem cell research.

This is only an early result from a very small study, but coming on the heels of reports just a few months ago, in which adult stem cells restored heart function to patients with advanced heart failure, the promise of stem cells again got just a bit brighter.

So yes, maybe we really can make the blind see again.