Scientists with University of Iowa Health Care have conducted a study that shows why muscles in healthy people don't tear or rupture when they exercise, as they might in a person with a congenital disease such as certain forms of muscular dystrophy.
Dr. Kevin Campbell, the senior study author and head of molecular physiology and biophysics at University of Iowa Roy J. and Lucille A. Carver College of Medicine and a Howard Hughes Medical Institute investigator, talks about the study.
In a healthy person, during exercise, what kinds of pressures are put on the muscles we are using?
When a healthy person exercises, especially exercise that involves lengthening contractions—like running down a hill—they can injure muscle cells, which are also called muscle fibers, because the muscles are trying to contract at the same time they're trying to contract, and this can lead to muscle injury.
What happens with regard to the muscles when those same pressures are put on a person with certain forms of muscular dystrophy?
With a person that has muscular dystrophy, this type of lengthening contraction can cause major damage to the muscles because they're susceptible to this type of injury.
What protein did the research team you lead identify?
The protein that we identified is called Alpha Dystroglycan, which is a protein that's found in muscle and is also defective in some forms of muscular dystrophy.
Can you explain to us non-scientists what the protein does in our healthy bodies?
This protein links the muscle cell membrane—which is a fragile structure, a lipid bilayer structure—to the surrounding basement membrane, which is a strong structure, and thereby allows the muscle cells to contract and stretch at the same time without developing injuries. In patients with muscular dystrophy, many times this protein is not functional, and thereby rendering those patients susceptible to muscle damage.
Some forms of muscular dystrophy do not have this protein, what does that mean for those patients?
In most cases the patients are producing a protein, but it's not functional, and so they don't connect their muscle cell membrane to the basement membrane, and that leads to the damage that's seen during these lengthening contractions.
Is the hope someday to be able to give this protein to people with muscular dystrophy to prevent muscle damage?
There's hope that either this protein could be injected into patients and go to the right place, the functional protein; or if there could be drugs developed that would allow the proper induction of this protein. So in both cases, if the protein was made, you'd be able to protect the muscle from the damage that occurs.
How far away is this study from being able to treat people with muscular dystrophy? What are the next steps?
The next steps are really drug development or protein therapy development. So it will still be some time before patients would be treated. |
