Eggs for Life
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Eggs for Life

Women who want to conceive but cannot often find it an emotionally wrenching experience. It�s long been thought that women are born with a limited number of eggs. Imagine if they could produce new eggs throughout life just as men create sperm continually. A new study suggests there is a way to replenish this limited reserve.

Researchers have isolated stem cells in adult human ovaries that could possibly become eggs. These same scientists first isolated stem cells in rat ovaries in 2004, called oogonial stem cells or OSCs. OSCs have a protein on their surface called DDX4.

Using fluorescent antibodies that bind to this marker protein, they isolated OSCs from mouse ovaries using a cell sorting machine. These cells not only went on to become eggs, they were fertilized with sperm and produced embryos.

Recently the research team applied the same technology to donated human ovaries from Japanese women undergoing sex reassignment surgery. Just as with mice, the team was able to isolate OSCs which, when grown in a Petri dish, became immature eggs, called oocytes. When implanted in mice that had human ovarian tissue grafted inside, they matured into eggs. The eggs also expressed several surface markers that confirmed they were indeed eggs.

Since US laws forbid fertilization of human eggs for use in research, it wasn�t possible to tell whether the eggs could actually develop into embryos. Even if they can, it�ll be some time before we�d know whether they�d produce healthy babies. What this study tells us is maybe this new technology can stimulate new egg production for infertile women.

What�s most provocative about this study is the suggestion that perhaps women retain the potential to produce eggs later in life, which goes against what scientists have always believed - that egg production is lost soon after birth.


For more information…

Unlimited human eggs 'potential' for fertility treatment
A BBC News article about the study that has shown it is possible to find stem cells in adult women which spontaneously produced new eggs in the laboratory.

Egg Stem Cells
Technology Review — "Jonathan Tilly may have discovered a way to slow the ticking of women's biological clocks. In a paper published in March, the Harvard University reproductive biologist and his colleagues reported that women carry egg stem cells in their ovaries into adulthood�a possible key to extending the age at which a woman might have a baby."

Stem Cells in Ovaries May Give Women More Eggs
Discovery News — "Contrary to the belief that women are born with a finite number of eggs, there may in fact be a way to replenish the supply, a new study suggests."

American Society for Reproductive Medicine (ASRM)
ASRM offers this series of fact sheets and info booklets on a variety of reproductive health issues and is an excellent source for accurate information.

From Medscape, information about infertility, including the etiology of it, the process of evaluation, options for treatments, and much more.