The goal of gene therapy is to restore the faulty enzyme so the body uses sugar properly, said Mah, a UF assistant professor of pediatric cellular and molecular therapy and a co-investigator on the study.
The dog, which comes from a line of dogs genetically prone to the disease, received its first dose of gene therapy the day after it was born, Mah said. The dog improved at first, often going as long as two to three hours without needing additional glucose to supplement its diet. But several weeks later the progress stopped.
When the dog was 5 months old, the researchers administered another dose of gene therapy, this time using a different type of AAV. Six weeks after the therapy, the dog was completely weaned off glucose supplements.
"We have never had to use any glucose supplementation since we weaned her off," Mah said. "She just gets fed normal dog food. That is a huge improvement in quality of life."
A few years ago, when Weinstein, Mah and other UF and National Institutes of Health collaborators began discussing the project, the longest a dog with the disease had lived was 28 days. The dog treated at UF is now 20 months old.
"The success is beyond what I would have imagined at this stage," Weinstein said. "To have a dog off treatment for 14 months that is clinically doing great with outstanding lab results is beyond what I even dreamt about."
Researchers hope to eventually establish a clinical trial in humans, but for now would like to test gene therapy in dogs again within the next year, Weinstein said.
"This is very exciting work and holds great promise for treatment of the disease in humans," said Joseph Wolfsdorf, M.B., B.Ch., a pediatric endocrinologist at Children's Hospital Boston and professor of pediatrics at Harvard Medical School who studies glycogen storage disease in children.
Finding better treatments for the glycogen storage disease is crucial because the disorder is
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University of Florida