Retinal transplants bear threefold fruit

Darkfrog submitted, created time 2 months 1 week (www.nature.com)

A formerly clinically blind woman's vision improved from 20/800 to 20/160--from one-fortieth of ordinary vision to one-eighth--after receiving donated retina. Six months after the operation, the started noticing the pendulum in her grandfather clock. For years, she found that she could read large-print books and emails and returned to her hobbies, knitting and sewing. Now, six years after her operation, her vision is fading, but it is still better than it was before the operation.

Of the ten patients who each received a four-millimeter square of retina and retinal progenitor cells, seven have experienced some improvement in their vision (though I suspect the woman described above is the most dramatic example).

However, Marco Zarbin director of the Institute of Ophthalmology and Visual Sciences at New Jersey Medical School, believes that this treatment will "never work as a standard clinical therapy."

First off, the efficacy of the procedure isn't so high, even after twenty years of experiments on animals. There are some results, but no evidence that the photoreceptors are hooking up or that new blood vessels are growing in to keep the transplanted tissue alive. There is evidence of these things happening in lab animals, but not in humans.

Second, the restored vision only lasts about six years. Nothing to sneeze at, but still.

Third, the transplanted tissue is obtained from aborted fetuses, which creates two separate problems: 1. A lot of people will object on ethical grounds , then a lot of other people will point out that the fetus was aborted anyway, then some more people will come back with that not making it okay and commentators on both sides will fill the airways until everyone forgets what we were talking about in the first place. 2. there isn't enough tissue to go around.

Ordinarily, I'd say, "This looks like a job for ...induced pluripotent stem cells!" because I simply don't think I can say enough good things about them (even though the kind of retinal tissue they're transplanting seems to be a little complex for the current state of the iPS field). However, there is another possibility. The fact that the photoreceptors don't seem to be connecting with the host's body and that the host doesn't seem to be growing new blood vessels and that the patients have recovered some vision anyway suggests that it might not be the tissue itself that causes the improvement. It might be the growth factors that are in the tissue.

So, this experiment gives us three things: 1. We know we can drop highly active cells in patient's sub-retinal areas without giving them eye cancer. The researchers seem to consider this a major victory. 2. We know that the recovered vision lasts for several years. 3. We know that there is another path to take. I call this pretty good.

Keywords: age-related macular degeneration opthalmology macular degeneration blindness stem cell research politics bioethics retinitis pigmentosa retina eyes sight vision transplants Vision Problems repair vision