I've been pretty good about my gym workouts lately. But I've realized that it's a lot more difficult to build muscle mass now than it was during my 20s. That's because, as we age, muscle stem cells become less able to repair injury and generate new muscle fibers.
Now a report in Nature Medicine outlines some interesting findings from the laboratory of Stanford microbiologist and immunologist Helen Blau, PhD, suggesting it may be possible to perk up a population of elderly stem cells through a combination of biophysical and biochemical cues.
As I describe in our release:
Blau and her colleagues also identified for the first time a process by which the older muscle stem cell populations can be rejuvenated to function like younger cells. “Our findings identify a defect inherent to old muscle stem cells,” she said. “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.”
Blau, who directs Stanford’s Baxter Laboratory for Stem Cell Biology, and postdoctoral scholar Ben Cosgrove, PhD, found that growing muscle stem cells from elderly laboratory mice (a 24-month-old mouse is roughly equivalent to an 80-year-old human, based on average lifespans) in a specialized matrix called hydrogel, coupled with a drug treatment to block an inhibitory pathway, caused the cells to divide rapidly. When implanted into elderly mice with a muscle injury, the cultured cells sprang to work.
“We were able to show that transplantation of the old treated muscle stem cell population repaired the damage and restored strength to injured muscles of old mice,” Cosgrove said. “Two months after transplantation, these muscles exhibited forces equivalent to young, uninjured muscles. This was the most encouraging finding of all.”
The researchers plan to continue their research to learn whether this technique could be used in humans. “If we could isolate the stem cells from an elderly person, expose them in culture to the proper conditions to rejuvenate them and transfer them back into a site of muscle injury, we may be able to use the person’s own cells to aid recovery from trauma or to prevent localized muscle atrophy and weakness due to broken bones,” Blau said. “This really opens a whole new avenue to enhance the repair of specific muscles in the elderly, especially after an injury. Our data pave the way for such a stem cell therapy.”
Previously: Making iPS cells safer for use in human through the study of a cellular odd fellow, New mouse model of muscular dystrophy provides clues to cardiac failure and Mouse model of muscular dystrophy points finger at stem cells
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