A group of Canadian researchers showed for the first time that muscle stem cells are directly affected by Duchenne muscular dystrophy, which could translate to better treatment of the degenerative disease.
This type of muscular dystrophy affects one out of 3,600 boys and results from a genetic lack of dystrophin, a protein involved in repairing muscle fibers affected by everyday movement, exercise, or injury. It leads to progressive weakness in muscle and death once the patient reaches his 20s or 30s.
Senior study author Dr. Michael Rudnicki, a University of Ottawa professor and regenerative medicine director at Ottawa Hospital, said that for nearly two decades, muscle weakness in Duchenne patients is thought to be caused by muscle fiber problems.
“[B]ut our research shows that it is also due to intrinsic defects in the function of their muscle stem cells," he said, optimistic about finding far more effective treatments for the condition.
The study was published in the journal Nature Medicine.
The team found that without dystrophin, muscle stem cells produce ten times fewer precursor cells subsequently creating fewer functional muscle fibers.
The protein also plays a key role in enabling muscle stem cells to detect their orientation in the surrounding tissue. Without it, the stem cells are unable to say which way is up or down, and then fail to divide and repair damaged muscle properly, explained Dr. Rudnicki.
While conducted in mouse models, the findings are expected to be the same in humans, as dystrophin is nearly the same among all animals.
The disease is currently being treated through physical therapy and steroids, which help slow its progression and manage symptoms. Gene therapy is in its experimental stage, but the team said these approaches need to be altered in order to target both muscle stem cells and fibers.
While uncertain if Duchenne muscular dystrophy will ever be cured, the researchers are targeting to turn the deadly condition into a chronic yet manageable one.
Dr. Ronald Worton, co-discoverer of the disease gene in 1987, welcomed the findings, citing their hope that the disease will be treated soon after their discovery of the responsible gene.
"This has been much more difficult than we initially thought,” said the retired doctor, expressing positivity that the breakthrough research will revive interest in patients and their families.
Dr. Rudnicki also noted that their discovery highlights the importance of basic or exploratory research.
Canadian research, for instance, is fast shifting toward applied research, leaving less funding and support for studies fueled by curiosity or, as in this case, “radically change” people’s perception of a disease.
