new study on stem cells in ovaries

[Evo]

I found this article rather interesting. I don't know how wise extending the reproductive age of humans would be though. There are other health risks to older women.

Once Thought Impossible, Study Shows Adult Mice May Generate New Eggs

"A half-century of conventional wisdom in biology may be wrong. A groundbreaking new study has found female mammals, in this case mice, make new eggs well into adulthood. If true for humans too, it would dramatically change thinking about the limits of reproduction."

http://abcnews.go.com/sections/Living/SciTech/fertility_mice_eggs_040310-1.html

[Monique]

That is very interesting! Another dogma overthrown :P

The next big question is whether Tilly's results in mice will apply to other mammals, including humans. "Reproductive aging is tough to translate into humans," explains Copperman. Most animals do not experience menopause the same way that humans do." Tilly believes he already has one tantalizing clue new egg formation may be taking place in humans. He points to two groups of women with cancer who were treated with chemotherapy cocktails. In one group, the cocktail included bulsulphan, the same drug Tilly used to kill off stem cells in the mice ovaries.

In the group that got bulsulphan, 72 of 73 of the women suffered premature menopause. In contrast, less than half the women whose chemotherapy did not include bulsulphan suffered premature menopause.

[Evo]

If the growth of new eggs in humans could be accomplished, perhaps this would significantly decrease the birth defects linked to childbirth for older women such as down syndrome.

[Monique]

Well, if the case of the mouse can be extrapolated to humans, it would seem that we already regenerate our own eggs, but apparently it slows down right before menopause.

But yeah, maybe some kind of 'booster' can be given that favours the growth of fresh eggs, which can then be fertilized the natural way.

[Moonbear]

Mice have been known to be quite different from humans when it comes to things like oocytes and reproduction. It's part of why it's so easy to clone mice or create transgenic mice for research, but so difficult in other species. So, I'm reserving my excitement until this same thing is shown in other species (I'm sure that now that this report is out and so highly publicized, it won't be long before others look for evidence of the same thing in a variety of other species).

Basically, the take-home message isn't really as big of news as it appears. It's saying that menopause isn't just due to running out of eggs, which we've known for quite a while now. Even under the old dogma of every woman is born with her lifetime supply of eggs, menopause begins before that supply is depleted. Therefore, even though the hype all seems to surround the idea of a "cure" for menopause, which I don't think should be treated as a disease that needs curing (granted, some symptoms need addressing, but do 50 and 60 year old women really need to be having babies?), I really think the interesting implications of this work lies in treating other forms of infertility. One obvious scenario that comes to mind is the woman given chemo or radiation treatment early in life for a cancer that responds well to treatment such that she is in full remission (and ultimately considered cured). She will now live a full and normal life, but finds she is sterile due to the treatments. Currently, women facing such treatment can opt to have eggs frozen and attempt in vitro fertilization later, but there are a lot of risks to this, and once the stored eggs are used up, even if no successful pregnancy has resulted, she's done with all her opportunity to have a child of her own. If, instead, she could have these stem cells harvested and reimplanted later, then it might be possible to "re-stock" her own egg supply, and conceive naturally.