Female mammals carry cells in their ovaries that can generate new eggs to produce healthy offspring, according to a study published online Sunday in the journal Nature Cell Biology, the Washington Post reports. In the past, many scientists believed women were born with a set supply of eggs, which would decline until they underwent menopause and became infertile. However, the new research is the first to identify cells that could stimulate egg production, which "raises the tantalizing possibility that it could someday lead to new ways to fight a woman's biological clock," the Post reports. In addition, the study's findings could provide researchers with a new source of eggs for the creation of embryonic stem cell lines.
For the study, Ji Wu of Shanghai Jiao Tong University in China and colleagues studied cells in mouse ovaries and identified a small number of cells that appeared to have characteristics of female "germline" stem cells, which theoretically could become eggs. The researchers extracted these cells, allowed them to multiply and then injected them into the ovaries of infertile mice. They found that the transplanted cells matured into eggs and also allowed some mice to conceive offspring. In addition, the researchers conducted tests and found no evidence that the offspring were abnormal, the authors said. Jonathan Tilly, professor of obstetrics, gynecology and reproductive biology at Harvard Medical School, said, "If you are looking to disprove that females cannot make new eggs, this paper proves it." He added, "This is the smoking gun."
According to the Post, if further research identifies similar cells in human ovaries, scientists potentially could use the findings to develop new treatments for infertility. "You could gain control over how fast the clock will tick," Tilly said. Such new techniques could allow women to "bank" their egg stem cells for later use and could provide options for women who face sterilization as a result of cancer treatment. In addition, physicians might be able to re-activate egg-producing cells for women who are infertile as a result of age, some experts claim. Roger Gosden, director of reproductive medicine at Cornell Weill Medical Center, said his facility encounters "a lot of patients who cannot get pregnant because they have run out of eggs or their eggs are of poor quality because of their age." He said this situation often compels women who want children to pursue adoption or egg donation. However, the new research "means egg donation from a fertile woman might not be necessary because she could have her own genetic child engineered from her stem cells," Gosden said.
However, many observers also cautioned that further research will be necessary to confirm the study's findings. "Although this is a dramatic study, these are huge claims," Gosden said. He added that the research "therefore accordingly should attract the most searing scrutiny." David Keefe, obstetrics and gynecology professor at the University of South Florida, added that the "aging process of the human egg differs fundamentally from that of the mouse egg." Evelyn Telfer, cell biology researcher at the University of Edinburgh, said, "Of course there are always aspects of any work that needs clarification, but this study appears pretty solid, and I am sure that several groups will be poised to try and replicate this work" (Stein, Washington Post, 4/13).
Reprinted with kind permission from nationalpartnership. You can view the entire Daily Women's Health Policy Report, search the archives, or sign up for email delivery here. The Daily Women's Health Policy Report is a free service of the National Partnership for Women & Families, published by The Advisory Board Company.
© 2009 The Advisory Board Company. All rights reserved.
Комментариев нет:
Отправить комментарий