A veterinary ophthalmologist at East Lansing’s Michigan State University has received a five-year, $8.2-million grant to research whether a gene therapy that prevents blindness in dogs can be applied to humans, the school reported Friday.
Simon Petersen-Jones of the College of Veterinary Medicine received the grant from the National Institutes of Health to further therapy for people who have a type of retinitis pigmentosa (RP). The disease is one of the most common inherited diseases of the retina and affects about one in every 3,500 people in the United States and Europe.
An earlier study showed a 100 percent success rate in helping dogs restore their night vision and stop them from losing their daytime vision. The progressive disease is similar to one in humans and often starts with night blindness, followed by a loss of peripheral vision and eventual total blindness.
PRA is an inherited condition in dogs that results from mutations in the same genes that cause RP. The retina, a thin tissue that lines the back of the eye, has light-sensitive cells called photoreceptors that convert light into signals, which are sent to the brain to be turned into information about visual images. In RP, the photoreceptors, rods, and cones of the eye are affected and progressively die.
“We know the disease in dogs looks like the disease in humans and progresses in a similar way,” says Petersen-Jones. He is leading the project and is a Myers-Dunlap endowed chair in canine health. “We were able to identify a shared gene and create a new therapy that effectively helped dogs see again. This new grant will allow us to build on our primary studies in preparation for an eventual clinical trial in human patients.”
Petersen-Jones and his team were the first to show that some dogs with PRA have a mutation involving a gene called cyclic nucleotide-gated channel b 1, which also causes a form of RP in humans. The researchers’ approach involved introducing a normal copy of the gene into the retina of affected dogs, restoring normal function and vision. This approach has been used to treat other inherited retinal degenerations.
“The therapy works extremely well, and we hope that this work will lead to an effective treatment for humans,” says Petersen-Jones.
The team is looking to obtain Food and Drug Administration approval to test the gene therapy as an investigational new drug.
Two groups of patients with RP and the gene mutations, one in the United States and one in Europe, will be enrolled as part of the project. Researchers will track progressive changes in the patients’ retinas that will be used as baseline measurements to assess the effectiveness of the treatment when it enters a clinical trial.
Additional lead researchers on the project include Bill Hauswirth from the University of Florida; Stylianos Michalakis from Ludwig-Maximilian University of Munich, Germany; and Stephen Tsang, from Columbia University.