Gene treatment eases eyes
Scientists have used a new gene therapy technique to repair nerve damage that causes vision loss.
Researchers say the findings in experiments on mice show promise for developing new gene therapies to treat both glaucoma and dementia.
The study also demonstrates how gene therapies could treat complex neurodegenerative diseases that are caused by multiple factors rather than a single genetic fault.
“Currently many gene therapies are targeted at rare diseases caused by a single genetic fault, where a missing or damaged gene can be replaced to treat the condition,” says Professor Keith Martin from the Centre for Eye Research Australia.
“More common neurodegenerative diseases like glaucoma or dementia are much more complex and caused by a range of genetic and other contributing factors.
“Although the research is in early stages, it shows promise for developing gene therapies for many of these common diseases to complement existing therapies.”
The study suggests gene therapy could be used to support optic nerve function by improving its ability to transport vital materials and information between the eye and brain.
Axons are long nerve fibres which transport electrical signals that allow nerve cells to communicate with other nerve cells and muscles. In many neurodegenerative diseases this transport system is disrupted, leading to chronic, progressive disease.
In glaucoma, the breakdown of signal transmission along the optic nerve leads to vision loss and blindness. In dementia, the build-up of tau proteins ‘tangles’ in the brain disrupts vital communication between brain cells, causing memory loss and cognitive decline.
In the latest study, researchers combined two key molecules into a single viral vector and delivered it to mice affected by glaucoma and dementia.
Before the therapy, both groups of mice had impaired optic nerve function with reduced transmission of electrical signals between the eye and brain. Those with glaucoma also showed signs of reduced vision.
However, after the therapy was delivered, optic nerve activity improved in both groups and the mice with glaucoma showed signs of improved vision.
There was also a possible small improvement in the mice’s short-term memory, which researchers now plan to test in a larger study to confirm the effect.