Researchers led by Evelyn Telfer at the University of Edinburgh have discovered that it might be possible to stimulate the growth of new eggs within the adult ovary, something previously considered impossible.
The study compared ovarian biopsies from Hodgkin lymphoma cancer patients who had received a chemotherapy drug called ABVD, unusual for the fact that it does not cause fertility problems, with biopsies from 11 healthy women. The ABVD patients appeared to have double or even quadruple the density of egg follicles.
Evelyn states “This was something remarkable and completely unexpected for us.” Her lab has gone on to submit a research paper, which is currently in review.
In 2012 Jonathan Tilly and colleagues at Massachusetts General Hospital in Boston found there may be stem cells in the ovary capable of producing new egg follicles. Evelyn’s discovery may be evidence of these stems cells at work.
The ABVD patient egg follicles resembled those of a prepubescent girl, supporting the idea they were recently formed.
The discovery has met with some scepticism from David Albertini, laboratory director at the Center for Human Reproduction in New York.
“Honestly, I think there are too many other ways to explain the results, one of which is that new eggs were made.” It is possible that the ‘new’ eggs were already in the ovary and have been brought to the surface through irritation by the chemotherapy drug.
It is also possible they are split egg follicles, which would double the apparent number of eggs.
What could this mean for women? Possibly, the discovery could lead to developments in IVF that help young women with poor fertility. Additionally it could give post-menopausal women another chance at motherhood.
Professor Nick Macklon at the University of Southampton added “there’s no evidence at this stage that these drugs would improve the odds for people who are having a poor response to IVF drugs.”
Evelyn Telfer said “We have to be very cautious about jumping to clinical applications […] There’s so much we don’t know about the ovary.”
Profile on: Evelyn Telfer
Professor Evelyn Telfer and her team of researchers published a paper last June, which demonstrated follicle density can be used as a measure of fertility.
This is “the number of immature eggs that a woman has within a certain volume of her ovary,” says Telfer. Speaking in a podcast for the School of Biological Sciences, she added “the number of eggs determines the fertile lifespan of a woman.” Scientists used donated ovarian tissue, obtained at the point of caesarian section, and counted the number of follicles present. The experimentally acquired data was found to correlate strongly with the predictions obtained using the mathematical model.
These findings were promising in two particular contexts: firstly, to predict how many eggs a healthy woman will have at any stage in her life, and secondly, to compare this value to a ‘perturbed situation’ (this might include women who have undergone chemotherapy or been affected by any illnesses that decreases fertility) and calculate how many follicles will remain.
Image: Evelyn Telfer