News: Research on mice suggests new fertility treatments


Scientists have turned mouse skin cells into eggs that produced baby mice, if successfully applied to humans, could someday allow women to stop worrying about the ticking of their biological clocks and perhaps even help couples create "designer babies."

Some experts say it could help millions of women who don't have working eggs of their own, whether because of a medical condition or cancer treatment, or because they are too old. "It could mean the reproductive clock doesn't tick for women anymore," said Hank Greely, a Stanford University law professor who studies the implications of biomedical technologies.

"I think it's a pretty large advance in the next generation of reproductive technologies for women," said Amander Clark, who studies egg development at the University of California, Los Angeles.

Discussion about policy and regulation "needs to begin now." The mice experiments were reported online Thursday in the journal Science by scientists at Kyoto University in Japan. The same group had previously reported work with male mouse cells that led to sperm. In the new work, they began with genetically reprogrammed skin cells from female fetal mice. The Japanese researchers turned these cells into an early-stage version of eggs.

Then they mixed them with mouse ovarian cells and implanted them into mice. Four weeks later they collected immature eggs, matured and fertilized them in the laboratory, and placed them into surrogate mother mice. The result: three baby mice, which grew into fertile adults.

That procedure is too cumbersome to be adapted directly for human use, experts said, and study co-author Katsuhiko Hayashi said in an email that it is also too inefficient. What's more, he and others said, biological differences between mice and people would have to be overcome before some version of the technique could be applied to women.

The hurdles are so big that some experts are skeptical about ever using the approach in people. "I don't think there's a lot of clinical potential here," said David Albertini, who has studies the development of eggs at the University of Kansas. Others are more optimistic but say it won't be easy. A human therapy is in "the quite far future," Hayashi said.

Greely, the Stanford law professor, speculated that in 20 to 40 years, the technique might make couples more likely to go through test-tube fertilization just so they could choose characteristics of their babies. In the future, Greely said, couples could create eggs and then have the resulting embryos analyzed genetically. Some others, however, said they doubt that practice would become widespread.

For example, the new work moves scientists closer to the possibility of tinkering with genes that would affect not only one person but also be inherited by future generations, which has long been controversial, said Dr. George Daley of the Harvard Stem Cell Institute.




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