Stem cells taken from the muscles of female mice are better at regenerating tissue than those taken from male mice, a new study finds.

This revelation could have a major impact on the development of stem cells as therapies for many diseases and conditions.

The researchers, whose work is published in the April 9 issue of the Journal of Cell Biology, found that female cells produced many more fibers than male cells.

They then did an experiment with both male and female cells to see if they would perform similarly.

The researchers injected stem cells from healthy mice into mice that had a disease analogous to the human genetic disease Duchene muscular dystrophy, which affects one in every 3,500 to 5,000 young boys in the United States, according to the U.S. Centers for Disease Control and Prevention.

People with this disease lack a protein called dystrophin that gives muscle cells structure.
After injecting the mice with the stem cells, the researchers measured the cells’ ability to regenerate muscle fibers that contained dystrophin.

Regardless of the sex of the host, the implantation of female stem cells led to significantly better skeletal muscle regeneration, say the study’s senior author Johnny Huard, also of the University of Pittsburgh School of Medicine.

The sex-related differences seemed to come from the cells’ stress responses. When cells are transplanted, the tissue becomes inflamed and the new cells are exposed to free radicals, which causes the male cells to differentiate, or stop making more of themselves.

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