Researchers working with laboratory rats have developed a technique that could someday help infertile women who lack usable eggs because of a hormone imbalance to conceive with new eggs created from their own ovaries.
Many women are unable to conceive because of a condition known as polycystic ovary syndrome, in which the ovaries fail to secrete enough hormones to stimulate egg production. Injury to the ovaries caused by radiation or surgery also can interfere with a woman’s ability to produce enough viable eggs, or oocytes, to achieve pregnancy.
Anthony Atala is director of the Wake Forest Institute of Regenerative Medicine in Winston-Salem, North Carolina. Atala says polycystic ovary disease is also commonly seen in older, pre-menopausal women. “What happens is as people get older, the fertility potential goes down and it goes down substantially. In fact, after age 30 it drops off markedly. And after age 40, it is very hard to get pregnant and it has to do with the egg quality that’s present in the ovaries,” he explained.
An estimated 10 percent of women struggle to become pregnant for at least a year. After that time, they are considered to be infertile.
Atala and his research colleagues stimulated the production of immature eggs from rat ovary cells. Atala says the cells are the equivalent of those in a 25-year-old woman.
They bathed the cells for one week in a petri dish filled with a nutrient-rich culture of chemical growth factors, and then placed the cells beneath a gel cover that allowed the cells to grow three-dimensionally instead of in a single layer. After three weeks, scientists tested the immature eggs - which were protruding from clusters of ovarian cells -- for growth, hormone production and their ability to express genes.
Atala says the young eggs produced hormones seen in normal, early-stage oocytes. "Our work is still in its very early stages," he said. "But it does really show that in fact cells be obtained and eggs can be developed. And they can be matured at least up to a certain point.”
Atala says the next step is to try to coax viable eggs from human ovarian cells. Atala envisions employing in vitro fertilization techniques, which would use the father's sperm to artificially fertilize the newly created oocyte outside the womb. The fertilized egg would then be returned to the mother's uterus for a normal gestation.
Atala presented the findings at the recent 2012 meeting of the
American College of Surgeons' Clinical Congress.