Can Animals Faithfully Model Human Health? Studies on metabolism, nutrition, cancer research … scientists and journalists look for similarities between animals and humans. However, problems can arise when researchers make predictions about human health based on the results of such studies.
Scientists refer to this concept as clinical relevance. Many agencies require researchers to justify the use of animal models by predicting the likelihood that the results will have an impact on human health. Meanwhile, journalists often write catchy news headlines to get attention, sometimes without critically evaluating the clinical relevance of a study; or worse, they neglect the fact that the scientists did the work on animals and not humans.
A great debate
The debate about the clinical relevance of animal models is very much alive on Twitter, through an account called @justsayinmice , which encourages users of social networks to retweet news that does not clearly indicate whether the results are from an animal model or of human volunteers.
Can we assume that conducting research on animal models will reveal information about our own health, and who is to blame when a news story includes broad claims about clinical relevance?
Animal models date back to 2000 BC
The first written records of animal testing date back to 2000 BC, when Babylonians and Assyrians documented surgeries and medications for humans and animals. Through the centuries, animals revealed much of the information that we assume today to be fact.
Since Galen’s discovery in the 2nd century AD. Since blood, not air, flows through our arteries, animal models are at the heart of scientific progress in the biosciences.
The key term here is animal model . For a model serves as a substitute and is not necessarily identical to the subject being modeled.
Animal models in modern medicine
“The use of animals is not only based on the great similarities in the biology of most mammals, but also on the fact that human diseases often affect other animal species. This is particularly the case for most of the infectious diseases, but also very common diseases such as type 1 diabetes, hypertension, allergies, cancer, epilepsy, myopathies, etc. Not only are these diseases shared, but also the mechanisms are often so similar that 90% of the veterinary drugs used to treat animals are identical or very similar to those used to treat humans “, explain Françoise Barré-Sinoussi and Xavier Montagutelli, from the Pasteur Institute in Paris, France in an article from the Future Science OA magazine .
There is no doubt that animal models have made a great contribution to the healthcare from which we benefit today. But it should also be noted that the results obtained in animals are not necessarily confirmed in human studies.
For what reason?
The truth is that although we share a significant proportion of our genetic code with the various animal models that scientists use in research, there are clear genetic differences.
Not all scientists see it this way.
In a 2018 article in the Journal of Translational Medicine , Pandora Pound, of the Safer Medicines Trust in the UK, and Merel Ritskes-Hoitinga, of the Radboud University Medical Center in Nijmegen, the Netherlands, argue that “preclinical animal models can never be fully valid due to the uncertainties introduced by species differences. “
The authors write that: “A predominant reason is that preclinical animal models cannot predict clinical efficacy and safety.”
Objective discussions
Do journalists misinterpret or misrepresent what scientists publish?
“I think the main problem is in the scientists and their press releases: how they sell the data and the results, how much evidence they find in relation to some devastating diseases, promises that are not yet there, even if they are based on interesting and important, but often preliminary, “says Vootele Voikar of the University of Helsinki in Finland, who uses mice in his research on neurological behavior.
“It usually means that more research needs to be done to find out if the findings are reproducible and applicable to the other conditions. Care or treatment is not available overnight, unfortunately, in most cases. However, overselling the find is often necessary to attract new research grants, “says Voikar.
Although the debate is served, many scientists use animals to model human diseases in the hope of improving our health. And, along the way, all the agents involved, we have a level of responsibility.
Referencia: Animal models are essential to biological research: issues and perspectives. Françoise Barré-Sinoussi and Xavier Montagutelli. Future Sci OA. 2015 Nov; 1(4): FSO63. Published online 2015 Nov 1. doi: 10.4155/fso.15.63 // Is it possible to overcome issues of external validity in preclinical animal research? Why most animal models are bound to fail Pandora Pound and Merel Ritskes-Hoitinga. J Transl Med. 2018; 16: 304. Published online 2018 Nov 7. doi:10.1186/s12967-018-1678-1
