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MERLON research examines how the use of animal testing to identify endocrine-disrupting substances in the EU can be reduced. The results show that although it is, in principle, possible to identify such substances without using animals, non-animal methods are still rarely applied.
Identifying endocrine-disrupting substances in the EU
Three criteria must be fulfilled to classify a substance as endocrine-disrupting:
1. It must cause harm (as assessed via animal tests or so-called new approach methodologies (NAMs) – NAMs are currently seldom used for this purpose).
2. It must interfere with hormone systems (NAMs are already used here).
3. A link must be demonstrated between the hormonal disruption and the adverse effect.
Alternative testing methods are, from an animal welfare perspective, clearly preferable. However, these methods are also much faster to carry out, which means that NAMs could significantly increase the efficiency of identifying endocrine disruptors in the EU.
“This is an area in which we are in urgent need of the support offered by digitalisation and new laboratory techniques. The WHO estimates that over 60,000 chemical substances are in global commerce. With today’s methods, we would not be able to test them all for the many harmful effects associated with endocrine disruptors – not even in 100 years,” says Marie Louise Holmer.
Endocrine disrupting substances pose risks to humans, animals and the environment, and can affect health in multiple ways. They may, for example, be carcinogenic, impair fertility, or interfere with the development of the brain and immune system. In the EU, substances can be regulated if testing confirms they are endocrine-disrupting – and such testing has so far primarily relied on animal experiments.
Animal testing has been widely debated for many years. Following a large public petition, the European Commission is developing a roadmap to outline how all animal testing for chemical safety assessments can eventually be phased out.
The researchers advocate a balanced approach. They argue that there is a need both to develop and validate alternative methods and to explore how these – potentially in combination – can predict harmful effects to the same degree as animal tests. At the same time, animal testing should be refined and optimised to provide as much valuable information as possible.
“We must ensure that the alternatives are just as effective as animal testing before animal methods can be phased out completely. That is why we also emphasise the continued need for animal testing until alternatives are fully accepted and routinely implemented in chemical regulation,” says Marie Louise Holmer.
One of the recommendations from the researchers is to bring together all stakeholders affected by the legislation in order to build consensus.
“We need, among other things, to determine when results from NAMs – or combinations of NAMs – are sufficiently robust and reliable to predict harmful effects and thus replace animal testing,” says Marie Louise Holmer.
Stakeholders could include national authorities (such as the Danish Environmental Protection Agency), relevant EU agencies, researchers, industry representatives, and NGOs.
New approach methodologies (NAMs)
NAMs include:
• In vitro tests – laboratory experiments carried out on cells or tissues outside a living organism.
• In silico models – computer-based models that predict the properties and effects of chemicals.
• Read-across – using data from one chemically similar substance to assess another.