Conventional thought would have it that a woman is born with a finite number of eggs in her ovaries, which get used up over time as monthly ovulation occurs. Thus for oldies like me over 40, this means trouble, as our eggs are aged and hagged and there might not even be enough of them left. But research in the past couple of years might just debunk this theory. Studies have discovered that there are stem cells in each ovary, and that ovarian stem cells could become new eggs. More research is needed to see to what extent these stem cells create eggs naturally that can be used by the body; but certainly the field of reproductive endocrinology is happily investigating how to utilize this to improve current IVF techniques.
In 2004, researchers at Harvard discovered ovarian germ cells in mice (germ cells are cells that originally developed into almost mature eggs throughout embryonic development and would fully develop throughout a females life and be released on ovulation), and found that by extracting them, they would develop into eggs, both in petri dishes and when injected into mouse ovaries. They named these cells oogonial stem cells (OSCs). Furthermore, scientists managed to fertilize these oocytes, and mouse pups were born, all starting from the OSCs.
Jonathon Tilly (director of the Vincent Center for Reproductive Biology at the Massachusetts General Hospital) applied these findings to human embryo’s, developing a method to identify stem cells in the ovaries. He found that while the stem cells make up less than 1% of ovarian cells, they do nonetheless exist, which was a big leap forward from conventional thinking. He also was able to pull these cells out, culture them in a lab and grow normal immature oocytes.
Reproductive endocrinologists are examining the ways in which this could change fertility treatments. If they can harvest ovarian stem cells, and develop them into oocytes in petri dishes, fertilize them and create babies, that may increase the prospects of having a healthy baby over using the woman’s older and more limited supply of eggs she was born with.
The first baby born using the findings of this research was in April 2015. Baby Zain was born in Canada, after his parents opted for the new type of IVF (marketed under the name Augment) that injected her eggs with mitochondria taken from her own ovarian stem cells. This is supposed to enhance the quality of eggs and their energy for embryonic development. Interestingly, studies in the past have done similar things – injecting mitochondria from a younger woman’s eggs into embryos of older IVF patients, and the rates of pregnancy and live births did increase, but it was halted due to ethical dilemmas around “three parent children”. If someone else’s mitochondria are injected into an embryo, that by definition means that some of their DNA is embedded into that child. I can see their point that it raises some ethical dilemmas. Being able to harvest a woman’s own stem cells and utilize that fountain of youth gets around the problem. Even so, the FDA in the United States has not approved Augment – they consider is gene therapy which is tightly regulated; the developers of Augment responded by taking it to other international markets. Time magazine reports that as of May 2015, three dozen women in four countries have tried the technique, and eight were pregnant at that time. All of those women had had at least one unsuccessful IVF attempt, some up to seven.
Whatever happens with the commercial reproductive endocrinology aspect of this is one thing; I think the really cool part is the discovery that these ovarian stem cells exist at all. I love it when science finds things that debunk current thought and potentially rewrite the text books. And like I said, it is still unclear in the research if these stem cells are regenerating eggs naturally in our bodies. I want to say, stepping away from science for a minute, that if God put them in our bodies they must have a function for us organically, not necessarily requiring scientific intervention and petri dishes.
So good news ladies, maybe our eggs aren’t all in one basket after all!