New hope to stop the female biological clock
In an encouraging step for female fertility, researchers from the University of Newcastle (UON) have been successful in identifying an antioxidant which has demonstrated potential to halt the aging process in female eggs.
With the average childbearing age continuing the climb in developing nations, the findings may provide a future solution for women who want to fall pregnant at an older age.
PhD student and lead researcher, Bettina Mihalas, along with a team within UON’s Reproductive Science Group, made the discovery by applying a model widely used in sperm research, to female eggs.
“What we found is a link between the deterioration of a certain protein in the female egg, which worsens with age, and its subsequent effect on the ability of chromosomes to separate.
“Further to this, we investigated the application of an antioxidant, which we observed to be successful in restoring the integrity of chromosome separation.
“The results are really encouraging as, with further study, this method could be explored as a possible solution to improving egg quality in mature women,” Ms Mihalas said.
Giving women the choice to start a family later in life
Women present with decreased fertility with increasing maternal age. The phenomenon is largely due to a decrease in the quality of her eggs, which leads to an increase in time to conception, rates of miscarriage and chromosome disorders such as Down syndrome.
This elevated incidence in chromosome disorders increases from approximately 2% for women in their 20s, to 35% in their 40s and 50% in their 50s.
“Women in developed countries such as our own are delaying child bearing to rightfully pursue their professional aspirations or ensure they have met the right partner,” Ms Mihalas said.
In Australia, the average childbearing age has increased from 27.7 years in 1987 to 31 years in 2010. In addition, the percentage of women having their first child later in life has also risen, with 7.1% of first time mothers aged 35-39 in 1987 increasing to 21.4% in 2008. Similar trends have been observed in other developed countries including the UK, US and Japan.
“I am hopeful that our results will aid the research in this area and prompt further work to facilitate women who embody this trend and are choosing to start a family later in life.”
The importance of the ROS factor
Two major known players affecting female fertility are age and the presence of reactive oxygen species (ROS).
An increase in intra-ovarian ROS has long been linked to the decline in egg quality associated with maternal ageing, which has been correlated with reduced embryo development and a decrease in live births.
The implications of the decline in egg quality leads to trouble conceiving, birth defects, miscarriage and infertility.
Co-author and UON reproductive researcher Professor Brett Nixon, said that despite the clear link, the way ROS elicits damage to eggs remains largely unexplored.
“With age, you get a marked increase in ROS and decrease in antioxidant defences, so you’ve essentially got a perfect storm,” he said.
Although the team’s testing was completed in-vitro, the results are incredibly encouraging for further research.
“What’s really exciting about our findings is that we’ve been able to identify that ROS targets and hinders the functionality of the tubulin family, which is a key protein responsible for chromosome separation.
“This will be a vital piece of knowledge moving forward with the research, as it paints a better picture of exactly what causes age associated chromosome abnormalities and miscarriage,” Professor Nixon said.
The future of antioxidant use
The antioxidant used in the study has proven to be of benefit in sperm research and young female eggs under the effects of ROS.
Co-author and UON reproductive researcher, Dr Geoffry De Iuliis, has taken a keen interest in exploring antioxidant use in therapeutic treatment and stressed that it is an area still in need of extensive investigation.
“If we can develop these antioxidants based on current technology, then we’d be in business.
“What’s difficult about making claims related to antioxidant use is that we just won’t know the extent of any benefits until we do the science.
“We need the antioxidant to pass through the gut intact, make it to the reproductive system and then see a therapeutic benefit.”
“Antioxidant use is still an area incredibly under-researched, so it’s imperative we work towards making them a viable therapy,” he said.
The research team, who are also members of the Hunter Medical Research Institute's Pregnancy & Reproduction group, hope the new findings will enable them to further explore the effects of ROS and various treatments to combat decline in egg quality, in a hope to ultimately provide women more options when considering starting a family.