When animal models are and are not scientifically viable
Goleta, CA - Nov 13, 2013
Animals and humans are examples of evolved, complex systems and therefore manifest diverse responses to the same perturbation. The fact that complex systems evolve over time explains the failures, and successes, of animals when used to model humans for response to drugs and disease and commonalities in basic physiology.
Drs. Ray Greek and Lawrence Hansen have published an article in the November 2013 issue of the journal Progress in Biophysics and Molecular Biology (Volume 113, Issue 2, Pages 231-253). In “Questions regarding the predictive value of one evolved complex adaptive system for a second: Exemplified by the SOD1 mouse,” Greek and Hansen explain Trans-Species Modeling Theory (TSMT) and apply it to studies of the SOD1 mouse used in research for amyotrophic lateral sclerosis.
TSMT can be summarized as follows. While trans-species extrapolation is possible when perturbations concern lower levels of organization or when studying morphology and function on the gross level, one evolved, complex system will not be of predictive value for another when the perturbation affects higher levels of organization.
For over a century, animals have been successful used in biomedical research to discover fundamental physiological principles of humans and animals. That the pancreas is involved in controlling blood sugar levels, the heart circulates blood in a circle, and the fundamentals of the immune system are similar among mammals are all examples of knowledge that involved studying animals.
Yet animal models have consistently failed to offer predictive value for human response to drugs and disease. For example, the poliovirus infected monkeys differently than humans and this delayed development of the vaccine for decades. Scientists were misled about HIV enters the human cell because of studies on nonhuman primates. Studying strokes in animals has led to multiple medical treatments that worked in animals but that resulted in harm to human patients. HIV vaccines that protected monkeys have actually increased the risk of contracting HIV in the volunteers that took the vaccine. After successfully navigating animal tests in drug development less than one out of ten drug make it to patients. Most fail because of efficacy or toxicity issues, both of which were studied extensively in animals. This is because drugs and disease affect higher levels of organization in animal and humans. These higher levels of organization are where the consequences of a complex system appear.
The flip side of all this is the fact that society has also lost cures and treatments because scientists believed the results from animals.
Drs. Greek and Hansen have explained why animals have succeeded in explaining basic phenomenon, like the function of organs, but have failed to predict human response to drugs and disease. Evolution has produced species that are superficially similar but very different in the details. At lower levels of organization, animals can inform us about humans. For example, animal and humans respond to the laws of physics. But at higher levels of organization (the focus of complexity science) the same drug or disease will elicit various responses depending on the species that is studied. Animal models offer no predictive value for humans in these areas and never will, regardless of how their genomes are modified.
TSMT has major implications for using animals in science in general. A proper understanding of TSMT will result in the elimination the vast majority of animals used in research and testing just as the Germ Theory of Disease eliminated miasma as a possible cause of illness.
“Questions regarding the predictive value of one evolved complex adaptive system for a second: Exemplified by the SOD1 mouse,” is available as an open-access article and can be viewed at http://www.sciencedirect.com/science/article/pii/S0079610713000539
For more information, contact:
Americans For Medical Advancement
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