Team identifies stem cells that repair injured muscles

Mar 05, 2009

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, which could have important implications in the treatment of injured, diseased or aging muscle tissue in humans, including the ravages of muscular dystrophy.

The newly identified stem cells 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, said Professor Bradley Olwin of CU-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, said Olwin. The stem cell population identified by the CU team within the satellite cells -- dubbed "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.

"This research shows how satellite cells can maintain their populations within injured tissues," said Olwin. "The hope is this new method will allow us to repair damaged or diseased skeletal muscle tissue."

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.

Stem cells are distinguished by their ability to renew themselves through cell division and differentiate into specialized cell types. In healthy skeletal muscle tissue, the population of satellite cells is constantly maintained, leading the CU-Boulder team to believe that at least some of the satellite cell population in the mouse study included stem cells.

For the study, the researchers injected 2,500 satellite-SP cells into a population of satellite cells within injured mouse muscle tissue. They found that 75 percent of the satellite cells that reproduced were derived from the previous satellite-SP cells injected into the tissue. The results demonstrated the injected satellite-SP cells were renewing the satellite cell pool, Olwin said.

"The key point here is we are not just repairing the tissue," said 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 implications for a number of human diseases, he said. In muscular dystrophy, the loss of a protein called dystrophin causes the muscle to literally tear itself apart, a process that cannot be repaired without cell-based intervention. Although injected cells will repair the muscle fibers, maintaining the muscle fibers requires additional cell injections.

Source: University of Colorado at Boulder

Explore further: Researchers uncover secrets of internal cell fine-tuning

add to favorites email to friend print save as pdf

Related Stories

Hoverbike drone project for air transport takes off

1 hour ago

What happens when you cross a helicopter with a motorbike? The crew at Malloy Aeronautics has been focused on a viable answer and has launched a crowdfunding campaign to support its Hoverbike project, "The ...

Study indicates large raptors in Africa used for bushmeat

2 hours ago

Bushmeat, the use of native animal species for food or commercial food sale, has been heavily documented to be a significant factor in the decline of many species of primates and other mammals. However, a new study indicates ...

'Shocking' underground water loss in US drought

2 hours ago

A major drought across the western United States has sapped underground water resources, posing a greater threat to the water supply than previously understood, scientists said Thursday.

Recommended for you

Researchers uncover secrets of internal cell fine-tuning

3 hours ago

New research from scientists at the University of Kent has shown for the first time how the structures inside cells are regulated – a breakthrough that could have a major impact on cancer therapy development.

Microscopic rowing—without a cox

4 hours ago

Many different types of cell, including sperm, bacteria and algae, propel themselves using whip-like appendages known as flagella. These protrusions, about one-hundredth of a millimetre long, function like ...

Illuminating the dark side of the genome

10 hours ago

Almost 50 percent of our genome is made up of highly repetitive DNA, which makes it very difficult to be analysed. In fact, repeats are discarded in most genome-wide studies and thus, insights into this part ...

User comments : 0