Latest Articles

Australian researchers discover a novel cause of preeclampsia

Preeclampsia is a life-threatening, pregnancy-induced disorder unique to humans. It is diagnosed by the sudden onset of maternal hypertension after 20 weeks of pregnancy plus one other symptom including elevated urinary protein, other organ damage or fetal growth restriction. If left unmanaged, preeclampsia can lead to maternal seizures (eclampsia) and death. Preeclampsia affects between 3-4% of all pregnancies in Australia, with 10,000 women diagnosed in Australia each year.

This dangerous condition is caused by a damaged placenta which releases toxins into the maternal blood stream, causing the clinical symptoms. It is widely accepted that preeclampsia arises due to abnormal placental development during the early stages of pregnancy however studying human placental development is very difficult and the mechanisms leading to poor placental development remain unclear.

New research published in Hypertension by Dr Ellen Menkhorst and Professor Eva Dimitriadis from the University of Melbourne and the Royal Women’s Hospital, has identified that a protein called galectin-7 is abnormally elevated in the early pregnancy placenta of women who subsequently develop preterm preeclampsia. The researchers were able to show that elevations of this protein in mice caused classic symptoms of preeclampsia, including hypertension and elevated urinary protein. Galectin-7 was also shown to regulate key components of the renin-angiotensin system, a central hormone system controlling blood pressure.

Overall this new research suggests that elevated placental production of galectin-7 during early pregnancy contributes to abnormal placental development and altered renin-angiotensin system function which may ultimately lead to the development of preeclampsia. 

The researchers hope this discovery will lead to the identification of new treatment options to improve placental development during early pregnancy and prevent preeclampsia.

Researchers propose a new concept for the cause of premature menopause

On average, women undergo menopause at the age of 51. However, early menopause ,which can occur between the ages of 40 and 45, and in some cases before the age of 40, has been associated with environmental exposures and genetic causes.

Previous research into the genetics of early menopause suggested that errors in genes for genome maintenance and DNA repair could be involved. Other research has proposed that an increased rate of death of ovarian follicles can deplete the reserve of follicles, thus causing early menopause.

An article in Human Reproduction by Dr Ray Rodgers at the Robinson Research Institute and Dr Joop Laven from Erasmus University Rotterdam proposes a new mechanism by which genetic changes in a specific region of the ovary could lead to follicle death. The researchers propose a link between genetic changes known to be associated with premature menopause, and those known to be involved in follicle degeneration (atresia). These findings support the concept that more follicles are likely to die in women who have less effective genes for genome maintenance. This in turn could lead to an earlier depletion in follicle reserves and ultimately to early menopause.

This new concept of follicle depletion will direct research that could ultimately lead to the development of novel strategies to prevent follicle depletion and early menopause.

Find the article here

Highlighting the impacts of pollution on wildlife reproduction

The environment is changing at an unprecedented rate due to human activity. Wildlife are increasingly confronted with many forms of anthropogenic pollution, including chemicals released through the usage and disposal of countless products, noise from traffic and industrial activities, artificial light at night, and heat pollution from urban heat islands and global warming. These various forms of pollution can disrupt many biological processes that are critical for successful reproduction.

A recent review led by Australian researchers highlights the scope of disruption of reproductive processes via a diverse range of pollutants. This includes not only direct effects on the physiology and development of reproductive organs, but also consequences on factors relevant to reproduction such as shifts in reproductive timing, impacts on gamete quality, and interference of sexual communication and selection. The authors highlight how these alterations to traits necessary for reproductive success can have detrimental repercussions on populations and wider ecosystems, as well as ramifications on the evolution of affected species. The authors then suggest a number of strategies that could be implemented to mitigate the concerning impacts of pollution, such as additional wastewater treatment steps, sound barriers, and reduced usage of artificial light.

Read the review article here

Australian researchers show a commonly used herbicide in Australia affects reproductive development in wallabies

Marsupials are experiencing devastating population declines across Australia, with 21 per cent of native mammals currently threatened with extinction. As their habitat becomes more restricted, marsupials are pushed into agricultural areas and forestry plantations, attracted to the food resources and rare permanent water sources.  This shift may increase their risk of exposure to agricultural contaminants, such as pesticides.

The herbicide atrazine is of particular concern due to its ability to disrupt the signals from reproductive hormones in a broad range of vertebrates, including fish, reptiles, frogs and rodents. Atrazine is of such concern that it has been banned across the European Union since 2003, due to its known impacts on the health of wildlife and potential impacts on humans.  However atrazine is used extensively in Australia, on cereal crops and in forestation to prevent the growth of weeds, with approximately 3000 tons used on crops annually.

Researchers at the University of Melbourne investigated whether atrazine disrupted development of the reproductive organs in marsupials. After exposure to atrazine at 450ppm in the drinking water during gestation and lactation, male offspring had a 20% reduction in penis length and altered expression of genes involved in testis development. This indicates that the hormone environment had been disrupted during a critical window of reproductive development.

This is the first study to show that endocrine disruptors (chemicals that disrupt normal hormone signalling) are able to affect developing marsupial pouch young through gestational and lactational exposure. These data raise major concerns for the use of pesticides in areas with vulnerable or endangered marsupial populations and illustrates the need for more stringent guidelines surrounding the use of known endocrine disrupting chemicals such as atrazine in Australia.

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New study investigates how ovarian development in the fetus could be linked to the development of Polycystic Ovary Syndrome (PCOS) later in life

Polycystic ovary syndrome (PCOS) is a common reproductive metabolic disorder of unknown cause(s). A person’s genes and history of development as a fetus both seem to affect the development of PCOS in later life, but how this happens is not known.

Researchers at the Robinson Research Institute in Adelaide formed a collaboration with international researchers to investigate whether genes known to be involved in PCOS are active during development of the foetal ovary. The research found that nearly all of the PCOS genes were activated during ovarian development and they clustered into three different patterns of activity, probably indicating different important roles in development.

These results are important because they provide clues as to the processes in fetal ovarian development that could be linked to PCOS later in life. The next step is to discover the factors that alter these genes during foetal development and to use this knowledge to identify strategies to prevent PCOS.

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Discovery of a new approach to fertility preservation in women undergoing treatment for cancer

Survival rates for many common cancers now exceed 80%, and there are an estimated 14 million female cancer survivors world-wide. Unfortunately, one of the major side effects of cancer treatment in women is infertility and premature menopause. This is because cancer treatments cause DNA damage in cells other than just the cancerous cells. Oocytes (eggs) are extremely sensitive to DNA damage and kill themselves via a process known as apoptosis, presumably to prevent genetic mutations to be passed onto the next generation.

Researchers in Dr Karla Hutt’s Ovarian Biology lab at the Monash Biomedicine Discovery Institute have found that when the oocytes are prevented from killing themselves they are able to accurately repair the damaged DNA. These animals can be treated with radiation yet produce healthy offspring without any genetic mutations or health issues. This study provides a fundamental step towards developing a truly effective fertility preservation strategy for female cancer patients and has important implications for prolonging women’s fertile lifespan.

Read more here.

Identification of a new mechanism that could underly disorders of foetal testis development

It is well known that perturbations to testis development in foetal life can underpin certain reproductive disorders in males, such as infertility, hypospadias, cryptorchidism and testicular cancer.

New research from the Hudson Institute of Medical Research has discovered a new mechanism in foetal testis development that could be vulnerable to environmental disturbances and could, in turn, have long lasting impacts on male health and fertility.

Previous research has shown that the protein activin A is required for the normal development of the seminiferous cords, the structures in the foetal testis that will eventually become the site of sperm production in the adult. Alterations in activin A can disturb the balance between the gonocytes (the foetal germ cells that will ultimately differentiate into sperm) and the somatic cells that support sperm production, leading to infertility.

Research by Kate Loveland’s group at the Centre for Reproductive Health has now revealed that alterations in activin A impact on the production of androgen within the testis and that this could be a key reason why the testis develops abnormally. Androgens are essential for male development, yet alterations in activin A caused important changes in the amount and type of androgens produced in the foetal testis.

This is important because circulating activin A can be altered by various conditions in pregnant women, including preeclampsia, infection or exposure to certain medications. This work suggests exposure to certain conditions during pregnancy could alter activin A at a key stage of testis development, and this could result in androgen imbalance and disorders of reproduction.  

See the article here

An extraordinary lizard that lays eggs and gives birth – watching evolution in action

The transition from egg-laying (oviparity) to live-bearing (viviparity) represents a key evolutionary innovation that has arisen multiple times across a range of animal groups. The evolution of viviparity is significant because it has enabled several vertebrate groups to become highly successful in exploiting novel environmental conditions. Understanding how viviparity evolves is a question that is linked to the evolution of biological diversity itself and, not surprisingly, has been the focus of considerable research interest.  A new study has now shed light on the possible genetic mechanisms underpinning the evolution of viviparity.

New work by a team of researchers from the University of Sydney has capitalised on the extraordinary reproductive biology of the three-toed skink, a small native lizard that exhibits geographic variation in reproductive mode.

While some skink populations are viviparous, others are oviparous. However, oviparity in three toed skinks is atypical and may represent an intermediate form between ‘true’ oviparity and viviparity. This is because, in contrast to the more conventional oviparity seen in other lizards, oviparous three toed skinks have a long egg retention stage, such that most of the embryonic development has already occurred inside the mother before the eggs are laid.

Using a transcriptomics approach, the researchers found functional similarities between differentially expressed genes between viviparous and oviparous three toed skinks. Intriguingly, genes expressed in oviparous three toed skinks over the reproductive cycle differed from more typical oviparous lizards.

These results suggest that the oviparous mode of reproduction seen in populations of three toed skinks may, indeed, represent an intermediate form between the ancestral egg laying state and live birth.  Importantly, they offer important insights into the genetic changes that may have given rise to viviparity.      

The paper was published in Molecular Ecology.

New strategies to improve reproductive success in Australian livestock

Australia is the World’s largest exporter of sheep meat and the third largest exporter of beef, with the red meat industry contributing billions of dollars to the national economy. The international market for both products is growing despite serious challenges within the Australian livestock industry, including drought and feed restriction, and now flood and bushfires.

These factors all combine to create an acute need for strategies to rapidly increase herd/flock size. Assisted reproduction technologies (ART) have the potential to do this and, when combined with genetic selection strategies, improvements in the quality of the herd and its ability to withstand external challenges can be achieved at the same time.

A recent review by Australian researchers provides a timely reminder of why, and how, knowledge of animal reproduction is being harnessed to optimise calving/lambing rates.

Much research has gone into improving the ART technologies themselves, leading to increased efficiency and decreased costs. However, the transfer of an ART-generated embryo to a recipient cow or ewe is another major determinant of the effectiveness of ART. The ability of a recipient to establish and maintain a pregnancy is a key factor in breeding success, and the major cause of reproductive loss is failure to maintain a pregnancy. The authors highlight that improvements in the selection and management of recipient animals could play a major role in increasing productivity in Australian livestock industries.

Australian researchers investigate whether supplements can improve egg quality and fertility in women

Oocyte (egg) quality has a major influence on female fertility and pregnancy outcomes, and scientists are trying to find ways to improve or preserve oocyte quality in women. Two recent papers from Australian researchers have addressed whether a particular supplement, nicotinamide mononucleotide, or NMN, can improve egg quality in women.

One study focussed on testing whether NMN could prevent the loss of eggs by women undergoing treatment for cancer. Cancer treatments, such as radiation and chemotherapy, cause the loss of the ovarian follicles (primordial follicles) that contain the oocytes, leading to ovarian insufficiency and premature menopause. The authors hypothesized that treatment of young mice with NMN, a precursor of the well-known cofactor NAD+, would protect their eggs from the cancer therapies. Unfortunately, intraperitoneal administration of NMN could not protect oocytes from either radiation or a chemotherapy agent under the experimental conditions used. It is likely that one action of cancer therapies is to inflict DNA damage in the eggs, so unless the damage is repaired quickly, the egg will die. The authors suggest that further research should investigate whether different NMN formulations could protect against DNA damage in oocytes during cancer treatment.

Another study addressed the problem of declining egg quality with ageing, an important problem as many women wish to fall pregnant later in life when their oocyte number and quality is rapidly declining. The authors showed that treating old mice with NMN in the drinking water could restore egg quality and subsequent fertility, and that this was recapitulated by treating eggs recovered from old mice in vitro. This exciting finding suggests that NMN supplementation could be a promising approach to preserve fertility in older women, but independent verification will be required. The authors caution against the immediate use of NMN supplements by patients until further research establishes how this treatment actually works.