Monday November 12 10:25 AM ET
"Study Suggests Way to Replace Diseased Eye Cells"
Study Suggests Way to Replace Diseased Eye Cells
NEW YORK (Reuters Health) - Scientists in Japan have found
a potential way to replace damaged cells in the eye's retina.
Their animal research suggests the technique could someday
prevent blindness from degenerative diseases of the retina such
as macular degeneration and retinitis pigmentosa.
In experiments with rat eye cells, Dr. Masatoshi Haruta of
Kyoto University and colleagues found that some genetic
tinkering could cause cells from the iris to take on new,
light-sensitive features like those of the retina.
The retina is a thin membrane at the back of the eye that
captures images that are then transmitted to the brain through
the optic nerve. Degenerative diseases of the retina are
leading causes of blindness. Once they are damaged, retinal
cells cannot regenerate on their own.
So Haruta's team investigated whether it might be possible
to get cells from the nearby iris to take on the retina's
duties. The surgical removal of part of the iris, they note, is
already an established practice in patients--used, for example,
to extract foreign objects or tumors from the eye.
The researchers took iris cells from rat eyes, then
introduced a gene called Crx that is normally expressed in the
photoreceptor, or light-sensitive, cells of the retina. With
the help of Crx, the iris cells expressed rhodopsin, a
substance in the retina that adapts the eye to changes in
light, according to the report released Monday in the advance
online publication of Nature Neuroscience for December.
In humans, Haruta's team notes, such a technique would
allow doctors to "feasibly obtain" a patient's own tissue for
use in retinal regeneration. It might be possible to remove
some iris tissue, coax the cells into taking on retinal
qualities, then transplant them back into a patient's eye.
Although this study is just a beginning, the researchers
conclude that the findings raise "the possibility that (iris)
cells constitute a potential source of retinal transplantation
in patients with retinal degenerative diseases or damaged
SOURCE: Nature Neuroscience 2001;12:10.1038/nn762.
Email this story - View most popular | Printer-friendly format
Click HERE to return to brain tumor news headlines