There’s a new vision for a rare, inherited condition.
Recent research has identified a one-time treatment that may repair damaged retinas and even reverse vision loss.
This treatment, tested on an unexpected source, also raises the prospect of repairing nerve cells in mammals, a feat once thought impossible.
Faulty copies of the CaBP4 gene cause poor vision from childhood by creating deficiency of a protein necessary for vision and signal transmission in the retina.
This protein can also affect dogs, leading researchers from Michigan State University to create a potential remedy by injecting the retinas of the animals with a harmless virus carrying a working copy of the gene.
The single-dose therapy improved vision in dim light, which is where the CaBP4 protein deficiency makes the most difference.
The treatment also helped areas of the damaged retina degrade less, while the outer plexiform layer that holds crucial connectors for vision and the synaptic ribbons inside the eye’s light-sensing cells expanded.
Growth of both the outer plexiform layer and synaptic ribbons is stunted when the CaBP4 gene isn’t working properly. The researchers compared this underdevelopment to building blueprints.
“One can essentially discuss the mutations in the retinal gene as a typo in a blueprint that makes the instructions incomprehensible to the system, resulting in a faulty design and subsequent vision loss,” study lead Billie Beckwith-Cohen said in a press release.
The treatment allows the growth of a layer in the eye that didn’t form as it typically would have during retinal development, establishing that the outer plexiform layer of the retina has the ability to change.
It also allows for synaptic features that support proper vision to grow properly, building a better support system for the whole retinal neural network.
Another highlight of the single-dose treatment is its ability to repair years of damage.
The team saw evidence of nerve cells being rewired, even after years of stunted growth in the eye and ensuing damage to nerve cell connections.
The benefits were long-lasting as well, as seen in follow-up periods three years after the initial treatment.
While the genetic condition is rare in both humans and dogs, the findings could provide other methods for repairing damaged neural networks.
One such application would look at the role that calcium signaling plays in handling cell communication in the eye — which also involves CaBP4.
The treatment has yet to be applied to humans. However, researchers are confident it will work.
“Our results show that gene therapy is not only capable of restoring retinal function but is also able to establish a nearly normal anatomical arrangement in the OPL of the retina,” they wrote in the paper.
