![]() | ||||
![]() |
![]() ![]() ![]()
Eye images courtesy Brian's Eye. ![]() Ganglion cells are one of three types of neural cells which make up the retina. By injecting stem cells into the retina, scientists hope to encourage the eye to make more of these bad boys. Image courtesy University of Delaware Department of Biological Sciences. Eye diagram courtesy Brian's Eye. The cellular layers of the retina, including retinal pigment epithelium, photoreceptors (rods and cones) and neurons. Courtesy The Schepens Eye Research Institute. |
![]() |
![]()
Cataracts can be removed. Corneas can be transplanted. Glaucoma can be treated. But dead photoreceptor cells are, well, dead. In diseases like age-related macular degeneration, retinitis pigmentosa and diabetes, doctors can do little but monitor the cell death in the retina.
Doctors have tried to transplant retinas, but with little success so far, leaving the millions of Americans with these diseases little cause for optimism. Now comes a ray of hope in the quest to restore the retina, courtesy of the all-purpose, handy-dandy stem cell . If you've been diligently reading The Why Files, you know that stem cells are the body's all-purpose cells. Stem cells are so handy, they remind us of Vise Grips, the plier tool that does almost everything. Stem cells can transmute into many kinds of cells. ![]()
An eye on the prize
In the gathering excitement over stem cells, this is not a theoretical proposition. Results from the lab of Michael Young, at the Schepens Eye Research Institute and Harvard Medical School, demonstrate that stem cells can repopulate a damaged retina. Eventually, this work could lead to treatment for some major blinding diseases. But that's far enough down the road to give us time to find out what he did, and what remains to be done.
The fine print
Curiously, stem cells are smart enough to read chemical cues in their environment. In the diseased eyes, they "know" enough to migrate to where they are needed, and to differentiate into some types of neurons. In normal eyes, they do nothing. "This result is strongly supportive of other recent studies, in which stem or progenitor cells seem to respond to injury cues," Young says. "Stem cells have the potential to rewrite the rules for developmental biology and have the potential to repair damaged retina." He adds, "This is the first definite evidence for survival, migration and nerve cell differentiation for transplanted stem cells in diseased eyes of mature rats." More broadly, it's also "one of the first demonstrations that stem cells can help repair the diseased, mature central nervous system." But we found more evidence. A group at Washington University has helped repair damaged spinal cord in rats, nine days after the damage, using neural stem cells. Returning to the vision research, before you set off any fireworks, remember that nobody knows if the new cells are working. "Now we have to determine the level of information being transferred," as Young says. Let's recap what remains to be done: ![]()
We're keeping our eye on the prospect that hearts could grow new arteries on demand. |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() | ||||
![]() |
![]() |
![]() Bibliography | Credits | Feedback | Search ©1999, University of Wisconsin, Board of Regents. |