Fish eyes may hold key to regenerating human retinas
by David Salisbury
Fish could hold the secret to retina repair
If you were a fish and your retina was damaged, it could repair itself and your vision would be restored in a few weeks.
Sadly, human eyes don’t have this beneficial ability. However, new research into retinal regeneration in zebrafish has identified a signal that appears to trigger the self-repair process. And, if confirmed by follow-up studies, the discovery raises the possibility that human retinas can also be induced to regenerate, naturally repairing damage caused by degenerative retinal diseases and injury, including age-related macular degeneration and retinitis pigmentosa.
The research was performed by a team of biologists at Vanderbilt University and is described in a paper titled “Neurotransmitter-Regulated Regeneration in the Zebrafish Retina” published online Mar. 9 by the journal Stem Cell Reports.
“The prevailing belief has been that the regeneration process in fish retinas is triggered by secreted growth factors, but our results indicate that the neurotransmitter GABA might initiate the process instead,” said James Patton, Stevenson Professor of Biological Sciences at Vanderbilt, who directed the study. “All the regeneration models assume that a retina must be seriously damaged before regeneration takes place, but our studies indicate that GABA can induce this process even in undamaged retinas.”
“This work opens new ideas for therapies for blinding diseases and has implications for the broader field of regenerative medicine,” said Tom Greenwell, program officer for retinal neuroscience at the National Eye Institute, which funded the study.
It turns out that the structure of the retinas of fish and mammals are basically the same. Although the retina is very thin – less than 0.5 millimeters thick – it contains three layers of nerve cells: photoreceptors that detect the light, horizontal cells that integrate the signals from the photoreceptors and ganglion cells that receive the visual information and route it to the brain.
In addition, the retina contains a special type of adult stem cell, called Müller glia, that span all three layers and provide mechanical support and electrical insulation. In fish retinas, they also play a key role in regeneration…..
Source: News Vanderbilt