Common environmental chemicals in diet affect fetal ovarian development

July 04, 2007

Lyon, France: Exposing a developing female sheep fetus to low doses of chemicals commonly present in the environment can disturb the development of the ovary, a scientist told the 23rd annual conference of the European Society of Human Reproduction and Embryology today (Wednesday 4 July). Dr. Paul Fowler, of the University of Aberdeen, Scotland, UK, said that this research would help to establish the importance of the effect of environmental chemicals for fertility.

Over recent decades there has been a dramatic increase in the production of industrial and agricultural chemicals and heavy metals, and this has coincided with widespread reports of breeding problems in wild animals. Fertility also appears to be declining among humans and there has also been a rise in reproductive defects observed in newborn babies.

Until now, most studies have looked at a short-lived exposure to high doses of single compounds, and have usually done so in mice and rats. Dr. Fowler and his colleagues decided to study the effect of long-term, low-level exposure to a cocktail of chemicals and heavy metals in an animal which has a long pregnancy, therefore better replicating the situation in the human.

"Our 'real life' model exposed developing sheep fetuses by pasturing their mothers on fields fertilised with either inorganic fertiliser, the control group, or, in the case of the treatment group, with digested human sewage sludge, before and during pregnancy", said Dr. Fowler.

" We examined the ovaries from the fetuses at day 110 of gestation, the equivalent of week 27 in a human pregnancy, and found that the ovaries from the fetuses where the mother was grazing the sewage sludge fields contained fewer eggs and also a number of protein abnormalities. These differences could have implications for problems such as cancer in later life."

The scientists hope that their Wellcome Trust-funded study will help to pinpoint the stages of pregnancy at which the developing fetus is most sensitive to disruption and also to measure the degree to which fertility is affected in the offspring after puberty, following their exposure as fetuses to environmental concentrations of a mixture of pollutants. "Switching some mothers from sewage sludge fertilised to control pastures before conception will tell us whether maternal exposure either before or during pregnancy does most damage to the offspring", said Dr. Fowler. "The sheep model is quite novel, with relatively little research in the area currently being performed in this way. One of the collaborators in the project, Professor Richard Sharpe from the MRC Human Reproductive Sciences Unit in Edinburgh, UK, has already found reduced testosterone and testis cell numbers in the male fetus exposed to sewage sludge at day 110 of gestation.

The group has applied for further funding to look more closely at the implications of the sheep findings for humans, for instance by comparing quantities of chemicals in the human fetus with those seen in sheep, and investigating whether changes induced in the sheep fetus could be a problem for the developing human. They also intend to look at the mechanisms by which exposure to environmental chemicals can cause defects in reproductive development in order to determine what might be done to reduce risks for the human fetus.

There is still considerable debate around the level of importance of environmental chemicals in cancer, obesity, infertility and other complex diseases which have multiple causes. "We hope our research will help in the drive for evidence-based policy making on this issue", said Dr Fowler. "If we can definitely establish that environmental chemicals are important in triggering these diseases, then we might be able to produce better treatments, but it would also be important to devise legislation to begin reducing the levels of such chemicals. We would then look to work with chemical and agricultural industries to find safer chemicals by improving how they assess fetal development effects. If such measures helped to reduce the rates of cancer, obesity and infertility, there would be considerable benefits in terms of the costs of healthcare."
-end-


European Society of Human Reproduction and Embryology

Related Cancer Articles from Brightsurf:

New blood cancer treatment works by selectively interfering with cancer cell signalling
University of Alberta scientists have identified the mechanism of action behind a new type of precision cancer drug for blood cancers that is set for human trials, according to research published in Nature Communications.

UCI researchers uncover cancer cell vulnerabilities; may lead to better cancer therapies
A new University of California, Irvine-led study reveals a protein responsible for genetic changes resulting in a variety of cancers, may also be the key to more effective, targeted cancer therapy.

Breast cancer treatment costs highest among young women with metastic cancer
In a fight for their lives, young women, age 18-44, spend double the amount of older women to survive metastatic breast cancer, according to a large statewide study by the University of North Carolina at Chapel Hill.

Cancer mortality continues steady decline, driven by progress against lung cancer
The cancer death rate declined by 29% from 1991 to 2017, including a 2.2% drop from 2016 to 2017, the largest single-year drop in cancer mortality ever reported.

Stress in cervical cancer patients associated with higher risk of cancer-specific mortality
Psychological stress was associated with a higher risk of cancer-specific mortality in women diagnosed with cervical cancer.

Cancer-sniffing dogs 97% accurate in identifying lung cancer, according to study in JAOA
The next step will be to further fractionate the samples based on chemical and physical properties, presenting them back to the dogs until the specific biomarkers for each cancer are identified.

Moffitt Cancer Center researchers identify one way T cell function may fail in cancer
Moffitt Cancer Center researchers have discovered a mechanism by which one type of immune cell, CD8+ T cells, can become dysfunctional, impeding its ability to seek and kill cancer cells.

More cancer survivors, fewer cancer specialists point to challenge in meeting care needs
An aging population, a growing number of cancer survivors, and a projected shortage of cancer care providers will result in a challenge in delivering the care for cancer survivors in the United States if systemic changes are not made.

New cancer vaccine platform a potential tool for efficacious targeted cancer therapy
Researchers at the University of Helsinki have discovered a solution in the form of a cancer vaccine platform for improving the efficacy of oncolytic viruses used in cancer treatment.

American Cancer Society outlines blueprint for cancer control in the 21st century
The American Cancer Society is outlining its vision for cancer control in the decades ahead in a series of articles that forms the basis of a national cancer control plan.

Read More: Cancer News and Cancer Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.