Experiments on human vs experiments on animals . What do you prefer?

From one side it is morally wrong to treat animals in this way solely for human benefit. But from the other side removing animals completely from the lab would impede our understanding of health and disease, and consequently affect the development of new and vital treatments. So the dilemma is what we a ready to sacrifice - the animal life or a human live. 

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"Trade off"

Animal experiments remain essential to understand the fundamental mechanisms underpinning malignancy and to discover improved methods to prevent, diagnose and treat cancer. Excellent standards of animal care are fully consistent with the conduct of high quality cancer research. There exists a special guidelines on the welfare and use of animals in cancer research. All experiments should incorporate the Three Rs (3Rs) principles.[3]

Three Rs 

The guiding principles underpinning the humane use of animals in scientific research are called the three Rs(in detail [2]). Basically the 3Rs include:

• Replacement: methods which avoid or replace the use of animals in research
• Reduction: use of methods that enable researchers to obtain comparable levels of information from fewer animals, or to obtain more information from the same number of animals.
• Refinement: use of methods that alleviate or minimize potential pain, suffering or distress, and enhance animal welfare for the animals used.

The 3Rs related to cancer research according to "Guidelines for the welfare and use of animals in cancer research" can be found in the Box 1 below.

Reliability of animal studies

Despite the general lack of success in translating animal models to clinical studies ( the average rate of successful translation from animal models to clinical cancer trials is less than 8%[11]) , animals are used in laboratories all over the world [7]. All attempt to derive probabilistic knowledge in one context that will generalize to humans. All are forms of modeling that will map onto the whole population with less than perfect precision and predict with even less precision the fate of any individual. Notwithstanding, these methods risk missing some important knowledge, or risk finding knowledge that doesn’t hold up in the clinical setting even to a point that is actually harmful once widely deployed.[5]

Ultimately, we come into the question as to whether we should spare resources and bypass animal models to evaluate therapy in humans directly. In the last decade, the FDA and the European Medicines Agency introduced guidelines for testing very small ‘micro-doses’ of drugs in humans [8]. These are concentrations less than a one-hundredth of the therapeutic dose. Because the concentrations are so low, the drugs can be tested in a small number of patients without the level of safety data normally required before a phase I study. These early ‘phase 0’ studies collect human data quickly by showing how the drug is distributed and metabolized in the body, and whether it hits the right molecular target. Approximately one-quarter of the molecules entering clinical trials fail due to pharmacological issues such as lack of absorption or penetration into the target organ [8]. With a direct test in humans, pharmaceuticals can determine earlier whether the drug is worth investing both time and money into clinical research. Phase 0 trials may be small in scope, but they require very sensitive tests to detect the minute quantities of the drug in the body and possibly its mechanism of action.[5]

Aside from phase 0 studies, a wide range of alternatives to animal-based preclinical research has emerged. These include epidemiological studies, autopsies, in vitro studies, in silico computer modelling, “human organs on a chip” - creating living systems on chips by mimicking a micro- biological environment with cells of a certain organ implanted onto silicon and plastic chips [9], and “microfluidic chips” - automation of over a hundred cell cultures or other experiments on a tiny rubbery silicone integrated circuit with miniscule plumbing [10].

In summary, animal models have been the basic translational model in the preclinical setting in elucidating key biochemical and physiologic processes of cancer onset and propagation in a living organism. Experimental tumors raised in animals, particularly in rodents, constitute the major preclinical tool of evaluating novel diagnostic and therapeutic anticancer drugs screening before clinical testing. The power of the animal models to predict clinical efficacy is a matter of dispute due to weaknesses in faithfully mirroring the extremely complex process of human carcinogenesis. The vast majority of agents that are found to be successful in animal models do not pan out in human trials. Differences in physiology, as well as variations in the homology of molecular targets between mice and humans, may lead to translational limitations. Even though animal models still remain a unique source of in vivo information, other emerging translational alternatives may eventually replace the link between in vitro studies and clinical applications.[5]

Usefulness of Animal trials

• There is no way to completely replace animal testing and research because the pathway to fully duplicating a whole, living system does not yet exist.

  Cell cultures and computers are limited in what they can model. A cell culture is not a full living system, like an animal or person, so it doesn’t show how a disease or drug works throughout the entire body. Researchers can study diseases like cancer cells in a petri dish, but they don’t behave the same way in a dish as in a living, breathing animal or person. So researchers must study treatments for diseases in a whole living system in order to discover and develop new drugs to fight them. They can’t do that in a single cell or with tissue in a petri dish alone.[4]
  
  

• Far fewer animals are used in scientific research than are killed for humans to eat. It has been estimated that 2.5 billion animals are consumed in the UK each year. This is around 700 times more animals than the number used in scientific research.

• The alternative to using animals in the lab would be to test new drugs in humans. It would be very difficult for researchers to find willing volunteers who would be able to provide informed consent to been involved in testing a new drug that hadn’t first been tested on animals.

• To stop animal research would also be unethical as it would dramatically affect the development of new knowledge and flow of treatments to those with health conditions who desperately need them.

• Where there are reliable alternatives in scientific research, animals are not used. There must always be a very clear scientific reason for research on animals to be considered.

• Through testing on animals we are able to ensure any risks of a drug are identified and minimized before it is tested on humans during clinical trials.

  
  

• Using animals in research has played important roles in Nobel Prize winning medical discoveries and breakthroughs

  In fact, since 1979, every Nobel Prize in Medicine awarded has had foundations in animal testing and research. The exception is the 1983 Prize awarded to Dr. Barbara McClintock for her work in plant genetics. To see a full list about the animal testing and research behind Nobel Prize winning work use a link . [4].

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References

[1] Yilin Cao, Joseph P. Vacanti, Keith T. Paige, Joseph Upton, Charles A. Vacanti: Transplantation of chondrocytes utilizing a polymer-cell construct to produce tissue-engineered cartilage in the shape of a human ear. In: Plastic and reconstructive surgery. Band 100, Nr. 2, 1997, S. 297–302 (Diskussion S. 303-304).

[2] Joanne Zurlo, Deborah Rudacille, and Alan M. Goldberg Article reprinted from "Environmental Health Perspectives" August 1996, vol. 104, no. 8

[3] Workman, P., et al. "Guidelines for the welfare and use of animals in cancer research." British journal of cancer 102.11 (2010): 1555-1577.

[4] https://fbresearch.org/

[5] Mak IW, Evaniew N, Ghert M. Lost in translation: animal models and clinical trials in cancer treatment. American Journal of Translational Research. 2014;6(2):114-118.

[6] http://scienceblog.cancerresearchuk.org/2011/06/21/animal-research-is-helping-us-beat-cancer

[7] Cook N, Jodrell DI, Tuveson DA. Predictive in vivo animal models and translation to clinical trials. Drug Discov Today. 2012;17:253–60. [PubMed]
[8]  Marchetti S, Schellens JH. The impact of FDA and EMEA guidelines on drug development in relation to Phase 0 trials. Br J Cancer. 2007;97:577–81. [PMC free article] [PubMed]
[9]  Wood C. Casey Research. 2011. Is Animal Testing about to become Obsolete?
[10] Orenstein D. Stanford Report: Stanford University. 2006. ‘Microfluidic’ chips may accelerate biomedical research.
[11] Food and Drug Administration: U. S. Department of Health and Human Services. 2004. Innovation or Stagnation: Challenge and Opportunity on the Critical Path to New Medical Products.

[12] http://genpsychology2012.blogspot.de/2012/06/animal-consciousness-and-their-role-in.html (04.07.2017)