A University of Colorado at Boulder research team has identified a type of skeletal muscle stem cell that contributes to the repair of damaged muscles in mice. It can have crucial implications in the treatment of injured, diseased or aging muscle tissue in humans, and muscular dystrophy.
The newly identified stem cells dubbed “satellite-SP” are found within populations of satellite cells located between muscle fibers and the surrounding connective tissue that are responsible for the repair and maintenance of skeletal muscles according to Professor Bradley Olwin of University of Colorado Boulder’s Molecular, Cellular and Developmental Biology department.
When muscle fibers are stressed or traumatized, satellite cells divide to make more specialized muscle cells and repair the muscle. The satellite-SP cells were shown to renew the satellite cell population after injection into injured muscle cells, contributing to recovery of muscle tissue in the laboratory mice.
A paper on the subject was published in the March 5 issue of the journal Cell Stem Cell. Co-authors on the study included the MCD biology department’s Kathleen Tanaka, John Hall and Andrew Troy, as well as Dawn Cornelison from the University of Missouri and Susan Majka from the University of Colorado Denver.
“The key point here is we are not just repairing the tissue,” said Dr. Olwin. “We injected a permanent, self-renewing population of stem cells. One advantage of using this technology is that we can use a relatively small number of stem cells and do the job with a small number of injections; in this case, only one.”
The research has far reaching implications for varying muscular diseases including the dreaded muscular dystrophy. Muscular dystrophy refers to a group of genetic, hereditary muscle diseases that weaken the muscles that move the human body. Muscular dystrophies are characterized by progressive skeletal muscle weakness, defects in muscle proteins, and the death of muscle cells and tissue. Nine diseases including Duchenne, Becker, limb girdle, congenital, facioscapulohumeral, myotonic, oculopharyngeal, distal, and Emery-Dreifuss are always classified as muscular dystrophy but there are more than 100 diseases in total with similarities to muscular dystrophy. Imagine the possibilities of a permanent, self-renewing population of stem cells, probably inserted with a single injection, which continuously renew the satellite cells, which are responsible for repair and renewal of defective muscle cells.