Kate Marusina, PhD wrote an article that appeared in Genetic Engineering & Biotechnology News titled: Animal Models Get Closer to Mimicking Humans.(Marusina 2012) Marusina stated: “Animal models contribute significantly to our understanding of molecular mechanisms underlying disease pathologies. However, few models predictably translate preclinical findings into what will happen in humans.” I agree that animal models are not predictive for humans but question how effective they have been in terms of mechanisms. The mechanisms for cancer in mice are very different from humans and this has led directly to the prediction problem.
Investigational drugs are able to cure mice from many diseases, but continue to fail in clinical trials. This fact is largely attributed to poor model designs that do not sufficiently reflect the pathophysiology of disease in humans. In addition, tremendous diversity of human genetic background, co-medications, dosing, timing of treatment, and many other factors greatly influence the treatment outcome.
Yep! That's the problem all right. But to imply that better design can solve the problem is naïve in light of the fact that humans and animals are evolved systems that are differently complex. That is exactly what Marusina is suggesting however, as the rest of the article describes new models that will no doubt be predictive for humans.
Marusina discusses the fact that mouse embryonic stem cells have been genetically modified in an attempt to build a better model. She then quotes Gary A. Churchill, PhD of The Jackson Laboratory as saying: “And yet, the inbred lab strains proved to be a poor system for discovery of specific genes associated with a particular trait, such as obesity or high blood pressure.”
Marusina then describes efforts to genetically engineer a better mouse. Even if these efforts are successful however, Michael D. Hayward, PhD of Taconic states: “However, it would be difficult to use such a population as a model to study function of individual genes. Taconic fully recognizes the profound influence of the genetic background of inbred strains on the phenotype. But we use this fact to our advantage to design our phenotyping methodology.”
The rest of the essay is basically an advertisement for various companies’ genetically modified animals.
Marusina’s article is typical of the animal model industry that, like the Popeye character Wimpy, lives by the philosophy of: “I'll gladly pay you Tuesday for a hamburger today.” Of course, Tuesday never comes nor does a predictive animal model. Aside from the fact that the animal model industry has been making such promises for decades, science has now advanced to the point that we understand why such models are not predictive and in fact never will be. Just as there will never be a perpetual motion machine, one evolved complex system will never be a predictive modality for another at the level of organization where drug and disease response occurs. Were this statement about complex systems in general no one would raise an eyebrow, as the statement would be considered obvious at this point in the history of complexity science. However, because there is so much money involved, not to mention ego, vivisection activists will pretend that complexity science is on the level of n-rays or Lysenkoism. The scientific community should be embarrassed when their own members deny the existence of such an important advance from the fields of math and physics.
I wonder if any of the vivisection activists that deny there is a prediction problem with animal models ever read essays like Marusina’s?
Marusina, Kate. 2012. Animal Models Get Closer to Mimicking Humans. Genetic Engineering & Biotechnology News. Vol. 32, No. 17, October 1, 2012 2012 [cited October 4 2012]. Available from http://www.genengnews.com/gen-articles/animal-models-get-closer-to-mimicking-humans/4529/?page=1.