Researchers rejuvenate old muscle stem cells so they behave like young ones, repair muscle better

This tale of two-year-old mice could make you feel young again. Two years in a mouse is equivalent to 80 human years and a CIRM-funded Stanford team has found that in those little old guys two thirds of their muscle stem cells are dysfunctional, which means they don’t heal well after a muscle injury.

No marathons on the running wheel for those guys—that is unless they get treated via a process the team led by Helen Blau also discovered. They found that the muscle stem cells in older mice have an elevated level of activity in a signaling pathway that impedes the ability of stem cells to replicate. They then found a drug that can block that pathway, which allowed the stem cells from older mice to proliferate robustly in the lab. When those cells were transplanted back into the mice they were able to contribute to repeated demands for muscle repair.

A press release from the University was picked up by HealthCanal and quoted Blau on the therapeutic potential of this discovery:

Our findings identify a defect inherent to old muscle stem cells. Most exciting is that we also discovered a way to overcome the defect. As a result, we have a new therapeutic target that could one day be used to help elderly human patients repair muscle damage.

One interesting aspect of the current study is it contradicts a prevailing theory on the poor function of stem cells in elderly populations. Blau noted that in the past researchers thought that some eternal factors in the environment around the muscle stem cells caused them to function poorly. So, finding a defect in the stem cells themselves provides a new target for therapy. You can read more about the CIRM grant to Blau for studying rejuvenated muscle stem cells here.

We blogged about her prior work developing a mouse model of muscle disease last fall when we posted the video below.

Don Gibbons