18 March 2022
‘Do we still need animals?’ is the provocative title of a meta-analysis on methods and models used in Alzheimer’s and Parkinson’s disease research, completed by an interdisciplinary team of researchers at VIB, KU Leuven, imec and VITO. After screening thousands of abstracts and papers, mapping both animal-based and animal-free methods, the authors conclude that calls to halt all animal research are premature, and that a more nuanced approach to monitor animal use is needed to inform policy discussions.
Animals in neuroscience
In the European Union alone, almost 10 million animals are used in biomedical experiments each year. This includes all animals used for basic and applied research, as well as for educational purposes and safety and regulatory testing.
Neuroscience accounts for a large proportion of this total number: nearly 1 million animals are used in basic neuroscience in the EU (the highest number for all fields of basic research), and another 300,000 in applied neuroscientific research (second only to applied cancer research).
With animal testing under increased scrutiny worldwide, the question to reduce these numbers is growing louder and louder, culminating in an EU parliamentary vote last September in favor of phasing out the use of animals in research.
What would this mean for research?
The push for quota or phase-outs is worrying scientists, in particular brain researchers, who claim animal research remains indispensable for scientific progress.
“The current ethical standards and strict legal frameworks already hold researchers accountable when designing and conducting experiments,” stresses Aerts. “Policymakers should treat researchers as partners—not opponents—in the search for and development of better models for disease.”
In an assignment from the European Commission’s Joint Research Centre, experts from VIB, KU Leuven, imec and VITO jointly screened neurodegeneration literature in search of human-centered methods and models. The exercise also yielded important data on animal-based approaches used in the field; these have now been published open-access in The EMBO Journal.
“Our screen of more than 13,000 abstracts on Alzheimer’s and Parkinson’s research highlights the great reliance on animal research in these fields. About two-out-of-three involved (non-human) animal-based methods and models, including animal-based cell lines,” says Liesbeth Aerts (VIB-KU Leuven), one of the researchers involved. “We obtained this result despite conducting literature searches that were specifically directed at identifying alternative methods, suggesting that this is still an underestimation of the real contribution of animal-based methods and models in this area.”
Monitoring and statistics
The research team is also convinced of the need for a more nuanced approach and interpretation of animal research statistics.
“Governments report the absolute numbers of animals used in research—in a given country or year, or for a given purpose. Because of legislative differences, it is already difficult to compare these statistics across the globe, let alone to gauge the relative use of animal versus non-animal-based methods,” says Aerts. “Relative and absolute numbers may tell a different story when a research field is expanding, as may very well be the case for neurodegeneration—a field suffering from historic underinvestment and increasing societal burden.”
Even at face value, animal use on its own says very little about whether non-animal approaches are viable alternatives, says Patrik Verstreken (VIB-KU Leuven): “Our literature review shows that an abrupt stop to animal experiments would significantly cripple the Alzheimer’s and Parkinson’s research fields. A move towards animal-free research is simply unrealistic.”
More nuanced policy
“Statements on animal replacement should be accompanied by a realistic assessment of the effects on research, especially in the case of neuroscience. Forced overstimulation of non-animal methods – by legal means – could lead to the promotion of low-complexity research models, with little added value for disease understanding,” says Dries Braeken (imec), whose team is focused on developing more complex non-animal models, which he believes should be used hand in hand with animal-based disease models.
Verstreken: “Policymakers setting the research agenda should carefully consider the compatibility of ambitions to reduce animal experiments and to find a cure, for example, for Alzheimer’s or Parkinson’s in the next decade.”
“The ultimate question is whether we will refuse to treat Alzheimer’s patients in Europe with medication developed in the US, China, Japan, or any other place where animal research will remain possible?” adds Bart De Strooper (VIB-KU Leuven). “It is important to realize that there is no medication for any indication on the market today that hasn’t been developed using or tested in animals.”