Eye rich source of flexible adult stem cells
Patients need not look any further than their own eyes to obtain perfectly matched neural (nerve) stem cells, say scientists. Researchers have identified adult stem cells of the central nervous system in a single layer of cells at the back of the eye. That layer, known as the retinal pigment epithelium (RPE), underlies and supports photoreceptors in the light-sensitive retina. Without it, photoreceptors and vision are lost.
These cells are also multi-potent, which means that they can form different cell types, though the researchers admit there is more to do to fully explore the cells' differentiation capacity, the journal Cell Stem Cell reported, citing a statement from the New York-based Rensselaer Institute's Neural Stem Cell Institute.
The new study shows that the RPE also harbours self-renewing stem cells that can wake up to produce actively growing cultures when placed under the right conditions. They can also be coaxed into forming other cell types.
"You can get these cells from a 99-year-old," said Sally Temple of the institute. "These cells are laid down in the embryo and can remain dormant for 100 years. Yet you can pull them out and put them in culture and they begin dividing. It is kind of mind- boggling," she added.
Temple's group got the RPE-derived stem cells they describe from the eyes of donors in the hours immediately after their deaths. But the cells can also be isolated from the fluid that surrounds the retina at the back of the eye, which means they are accessible in living people as well.
"You can literally go in and poke a needle in the eye and get these cells from the sub-retinal space," Temple says. "It sounds awful, but retinal surgeons do it every day." By comparison, access to most other neural stem cell populations would require major surgery.