Vet researchers develop treatment for dog blindness

Researchers at the School of Veterinary Medicine have developed a groundbreaking treatment for blindness in dogs, and potentially, humans.

The treatment is a gene therapy targeted at dogs with Best’s disease, a hereditary form of macular degeneration that occurs in humans as well as dogs, which results in blindness. Karen Guziewicz, a researcher, and Gustavo Aguirre, a professor at the Vet School have been working on a treatment for Best’s with a team from the University of Florida since 2006, when Aguirre realized that the vision problems of a dog he was examining had the same Best’s disease that was previously only found in humans.

“One day, I’m examining the dog clinically and the dog looked like a human,” he said. Its resemblance to a human face sparked his epiphany. Aguirre immediately sent the dog, a fluffy Coton de Tulear, off for genetic testing.

The results were scientifically thrilling for Aguirre. Not only did the dog have Best’s disease, but also the cause of the disease was the same as in humans — a mutation of the BEST1 gene that is typically inherited.

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Aguirre explained that certain dogs were more likely to have the mutated gene than others, similar to humans. The English Bull Mastiff is one of these breeds.

This discovery has significant implications for people afflicted with Best’s disease, or people suffering from macular degeneration in general. Aguirre’s finding led to the development of the new gene therapy treatment.

According to Guziewicz, the therapy is “the first attempt to treat this disease,” which did not have an effective treatment before their research.

Guziewicz describes their treatment strategy as, “We try to replace the mutated gene with the healthy one.”

Aguirre compares the therapy to a cargo truck, where the cargo truck is a virus that delivers a cell promoter, the “cargo,” into an affected cell in a dog with the disease. From there, the cell promoter changes “how the [mutated] gene is expressed,” he said.

“This is a tool,” Aguirre said, that can be potentially used to treat macular degeneration in humans, which is the “major cause of blindness in the developed world in the aging population.”

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“The new study by Dr. Aguirre and Guziewicz lays important groundwork for expanding the spectrum of retinal diseases that could be treated by gene therapy,” Josh Dunaief, professor of ophthalmology at the Perelman School of Medicine, said in an email.

However, it will take some time before this treatment can be used in clinical settings.

“We know it will work,” Aguirre says, but nevertheless he estimates it will take another five years before the treatment can go to clinical trials for dogs. “As a patient you think we’re moving like super cold molasses [but] we look at it as moving at the speed of light,” Aguirre says.

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