According to a study published in the “Stem Cell Reports”, experiments carried out on animals are inadequate for evaluating potential therapies against Alzheimer in humans. The problem is that brain cells of mice are much more sensitive to the effects of drugs that those in humans. As a result, this leads to an overestimation of the effectiveness of the drugs when they are tried on patients.
Much of the research to develop drugs against Alzheimer is focused on preparing drugs that stop the production of amyloid proteins that make clusters or plaques and surround the brain tissue.
In spite of the promising results on animals, these drugs with which clinical studies have been carried out, have failed to date. Researchers made use of brain cells originating from stem cells of patients suffering Alzheimer’s. Therapeutically relevant doses of drugs could not influence the amyloid plaques of such cells. According to the authors, it seems that “thanks to the data [...] generated from mice […] it has been overestimated the efficiency of these drugs on human neurons, leading to a hypothesis that is supported by the clinical failure of these drugs.”
Reference: Mertens J, Stüber K, Wunderlich, et al. APP processing in human pluripotent stem cell-derived neurons is resistant to NSAID-based γ-secretase modulation. Stem Cell Reports. 2013; 1:491-498.
Note: One thing is certain; according to Dr. Tony Lindl’s studies, 99.7% of these tests on animals are not transferable to humans.
http://www.animalexperiments.ch/data/pdf/transmiss_d.pdf
Another interesting report regarding this topic was broadcasted by the TV channel 3sat: http://www.youtube.com/watch?v=FKl-7xp1Rmk