Researchers have used stem therapy to restore movement in dogs with an animal version of muscular dystrophy. While not a cure, observers say the development holds promise of a treatment for the lethal, paralyzing disease, and gives a boost to the field of stem cell research.
Duchenne's muscular dystrophy is a genetic disease that affects about one in 3,000 children, almost all of them boys. By the age of 12, the children are wheelchair-bound. Most die in their teens and twenties of respiratory failure.
The disease is caused by a defect in the gene that produces a protein called dystrophin, which is needed in the production of muscle fiber. Without it, muscle tissue becomes flabby with fat and connective tissue.
About 10 years ago Giulio Cossu of the Stem Cell Research Institute in Milan, Italy and colleagues came across a type of stem cell in blood vessels that can be manipulated to grow into smooth and skeletal muscle cells.
The newly grown cells contain whole copies of the gene that make dystrophin.
Because they come from blood vells, researchers wondered what would happen if they simply injected the stem cells into the blood stream of dogs that had muscular dystrophy.
In a study published in Nature, Cossu's team reports the results of injecting a group of crippled golden retrievers with the dystrophin-producing stem cells.
"They could not extend the hind limb and still were jumping more or less like rabbits, very, very actively and for a long period of time," said Giulio Cossu. " And that's the first evidence of functional recovery."
In one dog, the researchers infused the engineered stem cells directly into the aorta - the major blood vessel that leaves the heart and supplies the entire body - and the animal was walking well after its last injection five months later.
Cossu acknowledges the work is significant, but says much remains to be done.
"It's much better to go cautiously and say one step by step we hope to get close[r] to a therapy, but we don't have a cure in our hands," he said.
If all goes very well, Cossu says preliminary human trials could begin in two to three years.
An opinion piece in Nature says the work pioneered by Cossu's team may be the first to realize a cure through stem cell technology for muscular dystrophy and other degenerative diseases.