How the cells act to preserve the deteriorating eye cells remains unknown, says Gamm. Like all cells, neural progenitor cells do many things and secrete many different types of chemicals that may influence the cells around them.
"The idea was to test the cells as a continuous delivery system" to shuttle an agent known as glial cell line-derived neurotrophic factor or GDNF, Lund explains. "It's not a sensible thing to inject the eyes many times over years. The idea was to use the cells as a continuous delivery system, but we found they work quite well on their own."
Lund has experimented with other cell types as therapies for preserving vision. The neural progenitor cells, a cell model developed by Wisconsin stem cell researcher Clive Svendsen, have been used experimentally to deliver the same growth factor in models of Parkinson's disease and Lou Gehrig's disease. Svendsen is also an author of the new PloS One report.
"It seems that the cells in and of themselves are quite neuroprotective," says Gamm. "They don't become retinal cells. They maintain their own identity, but they migrate within the outer and inner retina" where they seem to confer some protection to the light-sensing cells that typically die in the course of degenerative eye disease.
For researchers, the work is intriguing because the progenitor cells come from the brain itself, and not from the part of the nervous system devoted to vision.
"This cell type isn't derived from the retina. It is derived from the brain," says Gamm. "But we're not asking it to become a retina. They survive in the environment of the eye and don't disrupt the local architecture
Source:University of Wisconsin-Madison