Gene therapy for dogs could help humans with muscular dystrophy

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In a study published in the journal Human Molecular Genetics, researchers at the University of Missouri School of Medicine reported that they have successfully treated dogs with muscular dystrophy using certain forms of gene therapy.

The success of these treatments, they say, could pave the way for new gene therapy treatments for humans as early as 2017.

Video: Muscular Dystrophy Gene Therapy: ScienCentral News Video

The dogs in the University of Missouri School of Medicine experiment had Duchenne muscular dystrophy. Duchenne muscular dystrophy is the most prevent strain of the disease in humans, primarily affecting men. Patients with the disease can lose their ability to walk—or even breath—without assistance as muscle gets replaced with stiff, fatty, boney tissue.

According to the U.S. National Institute of Neurological Disorders and Stroke, nearly 250,000 people suffer from muscular dystrophy in the United States.

More importantly, there’s currently no cure for the disease, and, as study author Dongsheng Duan, a professor of medical research at the University of Missouri School of Medicine, points out, there aren’t even really any treatments that effectively treat the symptoms.

The success of the gene therapies in dogs could mark a breakthrough. “This is the most common muscle disease in boys, and there is currently no effective therapy,” Dr. Duan stated in a press release. “This discovery took our research team more than 10 years, but we believe we are on the cusp of having a treatment for the disease.”

Video: Gene Therapy & CRISPR Cas 9 [PPMD's 2016 Connect Conference]

In his review of the study, Robert Preidt, a reporter for US News, notes that these kinds of results are often tough to replicate in human trials. Indeed, it took University of Missouri researchers over 10 years to deliver their therapy to dogs safely, and human treatments are typically much more complicated.

The disease is caused by disrupting the production of something called dystrophin, a cohesive protein that supports muscle fiber strength.

Treatments are often difficult because the gene is so big- in fact, it’s one of the longest genes in the entire body.

Dr. Duan explains, “Due to its size, it is impossible to deliver the entire gene with a gene therapy vector, which is the vehicle that carries the therapeutic gene to the correct site in the body. Through previous research, we were able to develop a miniature version of this gene called a microgene. This minimized dystrophin protected all muscles in the body of diseased mice.”

Dr. Duan’s team administered their treatment to 2-3-month old puppies who were beginning to show signs of muscular dystrophy. In their paper, they report that the dogs began to develop normally around the 6-month mark.

So why use dogs to test this kind of treatment? “These dogs develop [the disease] naturally in a similar manner as humans,” Duan said. “It’s important to treat [it] early before the disease does a lot of damage, as this therapy has the greatest impact at the early stages in life.”