Animal testing: a gold standard?
The future of animal testing in five propositions
Animal testing plays an important role in the development of medicine and broader scientific research. However, the practice has been coming under growing scrutiny in recent years. The European Union and Dutch government aim to lead the way with animal-free alternatives. The question is: how do we achieve this goal? What are the opportunities and challenges facing the scientific community? How can we speed up this transition process? And how will this affect research into improving the treatment of animals? We will illustrate the current debate on the basis of five propositions, each of which is advocated by a different researcher.
Animal-free science will remain a utopia for the foreseeable future
Why do you support this proposition?
‘I'm not against the transition and I definitely welcome the search for non-animal testing innovations. However, those innovations are still far from adequate in my field of research. I research the brain, and we really don't have a good model of the brain as a whole: we simply don't know how the brain works yet. Organoids and organs-on-a-chip don't even come close to emulating the workings of the brain. The brain is an incredibly complex system, with different brain areas with their own unique functions and a whole network of different cell types that communicate with each other and other organs. You need an entire organism to understand how it all works and study all those interactions.’
Animal testing is often seen as the gold standard, but surely mice aren't the perfect model for many human research questions?
‘You obviously need to keep translating your results into human terms. We use mice because they are both different from people and similar enough. Animal models are incredibly useful, as long as you're aware of their limitations. I do research on fear and stress responses. Mice freeze up when they encounter something frightening. People can have the same response. A mouse may not be the best model, but they're definitely closer to human beings than a cell line in a petri dish.’
Laboratory animals are by far the best modelling system we currently have at our disposal
‘As a society, we can ultimately choose not to do any animal testing because of animals' intrinsic value, but that will have implications in terms of our research progress and the insights we're able to gain. That's just the price you pay. I really think it will be a long time before we can completely eliminate all animal testing. Laboratory animals are by far the best modelling system we currently have at our disposal.’
The Netherlands needs to intensify its efforts to transition to animal-free innovation
Why do you support this proposition?
‘The number of animal tests has stabilised at around 500,000 a year in recent years. I think that's a regrettable situation. We've come to blindly rely on animal testing. That's why we should be motivating researchers to explore non-animal testing innovations and come up with imaginative new ideas. That will allow us to innovate even more rapidly.’
ZonMw has received an incredible amount of promising research proposals for non-animal testing innovations in recent years, but we've had to be very selective due to funding issues. That just goes to show how many creative people there are with good ideas. Still, we will need to invest in them if we aim to bring their ideas to life. Last month, we presented an exploratory study to Carola Schouten calling for more funding for research on animal-free innovations. We carried out the study in collaboration with the National Advisory Committee on Animal Testing Policy. We believe this is the time to double down. We can find more creative solutions if we invest more money and effort.’
We can find more creative solutions if we invest more money and effort.
Some researchers believe the transition will effectively make any meaningful animal testing impossible.
‘I don't agree. ZonMw funds both animal testing and innovation. The two exist side by side. We're not throwing out the baby with the bathwater, so to speak.’
Others argue that research will move abroad.
‘That's theoretically possible, but I don't expect to see any massive exodus of scientific talent. We won't be banning animal testing unless there's a relevant innovation available. The debate should also be taking place on an international level. The Netherlands can't afford to stay in the vanguard alone; the countries around us will have to keep up with the transition. We're already working together to that end.’
Animal testing shouldn't be mandatory
Why do you support this proposition?
‘Chemical substances and medicines have to be safe for humans. The information we need to assess human safety has been recorded in guidelines. However, there shouldn't be any guidelines on the way in which we obtain this information (either through animal testing or non-animal testing). That's why I agree with the proposition. We don't necessarily need to get our safety assessment data from animal tests. We prefer to assess human safety on the basis of human biology and physiology rather than animals.’
Wouldn't safety be compromised if we abolished these laws and regulations?
‘Safety always comes first, but we can achieve that without animal testing. In fact, animal testing actually serves as a last resort in legal frameworks. The European Union is eager to reduce the use of animal testing in chemical and pharmaceutical safety assessments. Almost all legal frameworks – such as those covering industrial chemicals or pesticides – state that animal experiments should only be used if there is no other way of obtaining the necessary information.’
We don't necessarily need to get our safety assessment data from animal tests.
So why do researchers still regularly rely on animal testing?
‘There are animal-free alternatives for basic safety assessment areas such as dermal irritation, but that unfortunately doesn't apply to more complex aspects. Addressing that problem will require new innovations, which we aim to develop through the Virtual Human Platform for Safety Assessment consortium. In addition to developing as many non-animal testing innovations as possible, we also need to make sure these innovations can be used to assess safety. This will require cooperation between all the stakeholders: assessors, developers at the academy and industry. They'll all have to agree, and that also extends to any decisions on the basis of the results: that way, we can all be confident that things are genuinely safe. We still have a long way to go in that sense.’
The use of animal testing is a self-sustaining system
Why do you support this proposition?
‘There's a kind of inherent compulsion in our scientific system. We carry out research with a certain animal model and think we need to keep on using it. Everyone is standing on someone else's shoulders, and that's holding us back from exploring alternatives. You measure different things depending on whether you're using animal testing or non-animal innovations. Still, as long as you can kill animals to examine their organs, there's no real imperative to explore alternative methods. That's not just laziness: these systems create their own dynamics and justifications. It can be hard to escape from those patterns.’
I thought we only did animal testing when it was the best possible option?
‘The best possible option is dictated by habit, and that tends to be the focus of our entire infrastructure. Researchers are under so much pressure to publish that they can't afford to think about non-animal innovations. However, a lot of animal tests don't translate well to human patients. Every mouse is different, and that also applies to every lab mouse and every human being. A lot of animal testing also tends to be sloppy. For example, researchers often fail to use blinding even though that's very relevant. We should also be asking ourselves whether it's acceptable to use animals in such an instrumental way in the first place. Science has become a business, so we're not harnessing its full potential. An entire industry has sprung up around laboratory animals, and that makes it even more difficult.’
As long as you can kill animals to examine their organs, there's no real imperative to explore alternative methods
‘Still, we seem to have reached a tipping point, a paradigm shift. The animal experimentation committees have started to say: enough is enough. That also applies to researchers. We should be making much more use of big data and all our existing knowledge about patients. Patients should become the gold standard again rather than laboratory animals.’
Animal testing is still necessary for animal health research and education
Why do you support this proposition?
‘Most people probably don't realise that about a quarter of all animal experiments are carried out as part of veterinary education or animal health research. If the Faculty of Veterinary Medicine wants to provide good education, we have to let students gain experience with animals. While Medicine students often practise on each other, Veterinary Medicine students practise on dogs, horses or cows. The vets of the future need to gain practical experience. In addition to observing animals, they also need to hold them, perform procedures and see how they react. Most of that is classified as animal testing. Although we should obviously strive to reduce, refine and replace the use of animals and search for innovations, there will always be a need to gain experience with real animals. For example, students need to practise performing caesareans.’
‘Animal testing will also remain a crucial part of research aimed at future improvements to the quality of animal life. We can't simply replace all animal testing with innovations like computer models, in-vitro models or virtual reality. Behavioural research would be a good case in point: researchers need to study animals in their own environment. Research into medicines or animal feed is another good example. You need the entire animal in order to study the interactions between the various organs and functions. It's basically comparable to clinical trials in humans, except this involves animals so it falls under animal testing.’
These animal tests ultimately help us to improve animal health and welfare
We don't do clinical trials on humans if they are dangerous or potentially lethal.
‘That's true, but anything involving more discomfort than a careful injection is already considered an animal test. Taking three blood samples, for example. You always have to carefully consider the benefits and necessity, but there's no major burden on the animal. Only a small part of animal health research requires experiments that cause anything more than moderate distress. What's more, the aim is to ultimately improve animal health and welfare.’