Hormones are essential to human development. If the endocrine system is disrupted during foetal stages, it can have serious developmental consequences: An increasing number of children are born with malformed genitalia, and many have problems conceiving. We also see an increasing impact on brain development, leading to cognitive difficulties such as concentration and memory issues. Not only does this affect individuals, it also has major societal consequences.
Terje Svingen, Head of the Research Group for Molecular and Reproductive Toxicology at DTU Food, has no doubt that the many chemicals we are exposed to play a role in this development, and he has dedicated his working life to identifying and protecting humans from harmful chemicals before they are born.
"Endocrine disruptors are particularly problematic during the foetal stage. So, if there are chemicals that can cause irreversible damage to unborn children, we must do what we can to protect them from those chemicals," says Professor Svingen.
Protecting people from the most harmful chemicals is a daunting task, however. Around 100,000 chemicals are already on the market, and more are being added all the time. Researchers cannot possibly test them all—there is neither time nor money for that. And it is not their job either. It is the manufacturers themselves who are responsible for testing the chemicals they put on the market.
"As researchers, we advise the authorities and ensure that the manufacturers do the testing correctly and that the guidelines we prepare, e.g., under the auspices of the OECD, are up to date. We are constantly working to improve them so that they'll catch more harmful effects," says Terje Svingen.
There are several groups of known endocrine disruptors, e.g,. phthalates, which make plastic malleable, bisphenols, which are found in the inside coating of tins and on receipts, and fungicides, which prevent fungal attacks in agricultural crops.
Knowledge about how these substances affect living organisms at a molecular level is now being used in, for instance, computer models to predict the effects of other substances with similar structures. This can then be followed up with experiments in tissue cultures—cells grown in an artificial environment—and later animal testing, if the substance has effects that warrant a proposal for a ban.
Alternatives to animal testing on the horizon
When it comes to identifying the effects of chemicals, petri dishes and cell cultures will only take you so far and will usually not be enough to predict the effect on humans. Terje Svingen's research group therefore still carry out tests on rats. However, he emphasizes: "We only do animal testing when it's necessary to protect humans."
Terje Svingen is a board member on Denmark's 3R Centre (Reduce, Refine, Replace), which aims to ensure that as few laboratory animals as possible are used and to provide the best possible conditions for the laboratory animals that have to be used. Alongside his other projects, he is also working on developing new methods for testing chemicals that do not involve animal testing. He believes the project will succeed within the foreseeable future, but he is also worried that politicians will decide to ban the use of laboratory animals before new methods are ready.
"I think that might cause some unpleasant surprises in terms of harmful effects on humans. And even if the EU bans animal testing, it will likely still be legal in many other countries," he says.
