Stem cells in eyeball discovered

Washington: Scientists have discovered stem cells in the back of the eye which they say could be used to regenerate damaged tissues in the body.

The finding has the potential to help treat eye diseases like macular degeneration and, could also explain weird diseases where non-eye tissue grows in the eyes, said the
researchers at the Neural Stem Cell Institute of Regenerative Research Foundation in New York.

In the future, the researchers said, they hope to figure out how to switch on these stem cells within the eye, allowing diseased eyes to heal themselves though that`s a long way off.

The stem cells were found in a special layer of cells in the eye called the retinal pigment epithelium, or RPE, which lies underneath the retina -- the eye`s light sensor. The RPE
keeps the retina alive and functioning. But in diseases like macular degeneration, the RPE fails and the retina dies.

"We found stem cells within that pigmented layer, that retinal pigmented epithelium, we started testing these cells and found they could divide many times in culture," study researcher Sally Temple told LiveScience.

"They are a valuable source of new central nervous system cells, and we showed they could differentiate into different cell types as well."

The researchers took RPE cells from donor eyes and grew them in the lab. Surprisingly, even though the cells don`t grow in an adult human, they grew like gangbusters in the lab.

When the researchers cultured cells individually, they found that only about 10 per cent of the cells were actually matured -- the others, which were discovered to be stem cells,
remained dormant.

The researchers, who detailed their work in the journal Cell Stem Cell, were able to treat these cells with different chemicals to make them turn into fat, brain and other types of
cells, proving they were what researchers call "multipotent," meaning they can turn into a variety of different cell types.

In the future, researchers may be able to harvest these stem cells from a person`s eye, culture them in the lab, and then re-inject them to treat a disease.

Even better, if the researchers could find the particular conditions or chemicals that make the cells grow in the lab, they would be able to figure out how to turn these stem cells
on while still in the eye to repair damaged or diseased RPE.

"We have the cells activated in culture, and we can figure out what factors can make them grow and activate them in vivo, that`s one of the things we would love to do," Temple said.

"Animals like certain amphibians can regenerate their eye tissues and you feel as if evolutionarily we are now more complex, we should have that ability hidden within us. That`s what we are really hopping to release here."

The researchers are still working to understand the cells` ability to form different kinds of cell, specifically, what different types of cell they can turn into.

"They are a little bit different than the neural stem cells that have been found before, based on the cell types they make," Temple said. "They are a pretty unique type of stem cell."