BETHESDA, Md., Oct. 14 (UPI) -- Using gene therapy, researchers were able to halt the progress of retinitis pigmentosa in dogs, offering hope they may be able to save the vision of people with the eye condition.
Retinitis pigmentosa is an inherited condition characterized by the degeneration of the retina, the light-sensitive tissue in the back of the eye, which leads to blindness. Roughly 1 in 4,000 people have the condition.
"The study shows that a corrective gene can stop the loss of photoreceptors in the retina, and provides good proof of concept for gene therapy at the intermediate stage of the disease, thus widening the therapeutic window," said Dr. Neeraj Agarwal, a program director at the National Eye Institute, in a press release.
Roughly 70 percent of people with the x-linked form of the condition carry a genetic mutation that leads to loss of function of the GTPase Regulator, or RPGR, gene that encodes a protein essential to the function of photoreceptors in the eye. The cells are what converts light into signals sent to the brain.
Researchers at the University of Pennsylvania and University of Florida combined healthy RPGR genes with an adeno-associated virus, treating one eye of dogs who have the disease and leaving the other eye untreated as a control.
Using serial imaging and immunolabeling, the researchers were able to see the injection of healthy genes into the animals' eyes helped preserve the function of photoreceptors in the treated eye. The health of the dogs' vision was confirmed in maze tests under dim light, as they performed better with the treated eye than with the untreated one.
The researchers said they plan to continue testing the safety of the treatment, as well as any risk for potential toxicity of the virus, before moving on to a clinical trial with people.