A common cancer drug triggers the development of new eggs, an outcome which was previously thought to be impossible, found scientists which have offered new hope to infertile women.
It is possible to reverse the clock and coax the ovaries back into a pre-pubescent state where they begin to produce new eggs, researchers at the University of Edinburgh proved in a discovery hailed as “astonishing”.
Since the eggs grow old, become damaged and eventually run out entirely, conceiving becomes harder with age as women are born with all their eggs. But scientists noticed that up to 10 times the number of eggs as healthy women were found in women who had undergone chemotherapy for Hodgkin’s Lymphoma with a drug combination known as ABVD. The cancer drugs may actually have improved their fertility, instead of damaging the chance of having a baby.
New follicles, the hollow hair-like structures which each produce a single egg, in the ovaries are produced by the shock of chemotherapy may trigger stem cells in the ovaries, the researchers speculate.
“We were astonished when we saw what had happened to the tissue. It looked like pre-pubescent tissue with a high density of follicles and clustering that you don’t normally see in an adult. We knew that ABVD does not have a sterilising effect like some cancer drugs can, but to find new eggs being made, in such huge numbers, that was very surprising to see,” lead researcher Professor Evelyn Telfer, of the University of Edinburgh’s School of Biological Sciences said.
“It looks like something is being activated probably in the germline or stem cells and we need to find out what that mechanism is. It could be that the harshness of the treatment triggers some kind of shock effect or perturbation which stimulates the stem cells into producing new eggs,” Telfer added.
“I think it’s a pretty big deal. It is the first time that we have ever been able to see new follicles being formed within the ovary, and it may only be a small number of women, but it is significant that the same effect was seen in all of the women on ABVD. The outcome may be significant and far-reaching.”
Alongside tissues from 12 healthy women, scientists analysed samples of ovarian tissue donated by 14 women who had undergone chemotherapy.
Compared with tissue from women who had received a different chemotherapy, or healthy women of a similar age, the tissue from eight of the cancer patients who had been treated with ABVD had between four and 10 times more eggs, they found.
Appearing similar to tissue from young women’s ovaries, the ovarian tissue was seen to be in healthy condition.
How to bring the eggs to maturity is what scientists intend to look for after understanding how they were created in the first place even though the eggs are still in an immature state. It is unclear if the eggs in their current form would be functional.
How women could produce more eggs during their lifetime, which was until now thought to be impossible could be helped to be understood by scientists if research can reveal the mechanism.
To better understand the biological mechanisms involved, each of the four drugs that combine to make ABVD – known as adriamycin, bleomycin, vinblastine and dacarbazine, would be studied to examine the separate impact of each in future studies.
“This is a very small but extremely interesting study. It’s very early days but may give an insight as to how the ovary can make new eggs, which previously we thought was impossible. It’s particularly fascinating that a commonly used chemotherapeutic agent to treat cancer in young girls has been shown to cause this effect,” Professor Charles Kingsland, a fertility expert of Liverpool Women’s Hospital, said.
(Adapted from CNBC and Telegraph)