New study finds key to improving fertility in older woman

Researchers have unlocked a potential missing link that may reverse age-related fertility decline and improve the quality and quantity of eggs in older women.

In what has been described as human reproduction’s “holy grail”, scientists in China have announced promising results in enhancing fertility in older females.

The results of a preclinical study in mice published on Tuesday in the journal Nature Aging suggest for the first time that increasing a substance called spermidine may reverse age-related fertility decline and improve the quality and quantity of eggs in older women.

Spermidine is a natural compound found in all cells and helps to extend lifespan in many organisms.

The authors say the study could one day increase the female reproductive lifespan in humans. Picture: iStock

It is known to offer health benefits from regenerating cells to protecting against age-related disease, but this research suggests it declines in the ovaries of older females.

The international study, led by Professor Bo Xiong from the Nanjing Agricultural University in China, found that supplementing spermidine in older mice improved follicle (early egg) development and IVF potential.

The study is the first to evaluate the benefits of additional spermidine on the “aged female reproductive system” and the authors say it could one day increase the female reproductive lifespan in humans.

Providing expert reaction to the study, University of Melbourne Associate Professor Alex Polyakov says while it is early days, the results are “very exciting”.

The research is described as groundbreaking because female age remains the main obstacle to IVF success. Picture: iStock

The fertility specialist says further studies to replicate and confirm the findings are needed and he is in early discussions to do those in Melbourne.

“The implications of these findings are far-reaching. One of the main issues in reproductive medicine is the ever-increasing average age of motherhood,” Associate Professor Polyakov said.

He says the researchers in this study noticed spermidine levels tended to decline in the ovaries of ageing mice when compared to young mice, but when this was supplemented, it increased spermidine levels in the ovaries and helped eggs to grow and mature, enhanced the ability for eggs to be used in a lab for fertilisation, and also improved early embryo formation.

Associate Professor Polyakov said while tremendous advances in fertility treatments over the past few decades resulted in drastically improved IVF success rates, female age remained the main obstacle to success since IVF cannot counteract the effects of age on the quality and quantity of oocytes (immature eggs) that can be obtained.

He said the loss of good-quality oocytes was gradual in women, but accelerated from the mid-30s and by the age of 45 it was unlikely that natural conception would take place.

“The holy grail of reproductive medicine would be a technique or treatment that could reverse the effect of age on the ovaries,” Associate Professor Polyakov said.

Experts say IVF cannot yet counteract the effects of age on the quality and quantity of oocytes (immature eggs).

He described the study as complex and groundbreaking, but preliminary and cautioned that while it was brilliantly conducted, further validation and confirmation was required before they are accepted at face value.

“Additionally, one must be mindful of the differences in physiology between species. Humans are not mice, and what appears to have an effect on other species does not always translate into a useful therapy in humans,” he said.

“Therefore, while showing tremendous promise, the findings of this study must be interpreted with great caution and further research is clearly required to apply these findings to human reproduction.”

In a statement Professor Xiong and his colleagues agreed that further research is needed to investigate if their approach can be safely and effectively translated to humans.