Scientists say Stem Cells from Female Mice Superior

Women are superior in the world of mice when it comes to stem cells, according to Children's Hospital of Pittsburgh scientists.

Stem cells from the muscles of female mice, on average, were twice as good at growing muscle tissue as stem cells from male mice, researchers reported in the Journal of Cell Biology. They tested the use of stem cells gathered from muscle in mice with muscular dystrophy.

"For muscles, the female cells are clearly superior," said Johnny Huard, director of the Stem Cell Research Center at Children's and senior author of the journal article.

Huard began looking into gender differences when he noticed that most stem cells surviving after transplant at the center came from females.

The discovery means that stem cell scientists should consider the gender of stem cell donors when analyzing research results, said Amy Wagers, a scientist with the Harvard Stem Cell Institute who is familiar with the research but did not participate in it.

"I think it is an important variable to consider," said Wagers, who also is an investigator at the Joslin Diabetes Center in Boston.

But, because the results were variable, Wagers said, "I would interpret this cautiously. It's intriguing but focuses on one particular population."

Mice -- and people -- with muscular dystrophy have a genetic mutation that causes them to lack a protein called dystrophin, needed for muscle fiber to function normally. Researchers in several countries are hoping that by infusing healthy muscle-building stem cells into people with the disease, they will generate new dystrophin.

Unlike controversial embryonic stem cells, stem cells derived from muscle can only become muscle. Female stem cells might not be better across the board, said Huard, who is testing bone-derived stem cells.