Humane Research Alternatives
Besides saving countless animal lives, alternatives to animal tests are efficient and reliable. Unlike crude, archaic animal tests, non-animal methods usually take less time to complete, cost only a fraction of what the animal experiments that they replace cost, and are not plagued with species differences that make extrapolation difficult or impossible. Effective, affordable, and humane research methods include studies of human populations, volunteers, and patients as well as sophisticated in vitro, genomic, and computer-modeling techniques.
Forward-thinking companies are exploring modern alternatives. For example, Pharmagene Laboratories, based in Royston, England, is the first company to use only human tissues and sophisticated computer technology in the process of drug development and testing. With tools from molecular biology, biochemistry, and analytical pharmacology, Pharmagene conducts extensive studies of human genes and how drugs affect those genes or the proteins they make. While some companies have used animal tissues for this purpose, Pharmagene scientists believe that the discovery process is much more efficient with human tissues. "If you have information on human genes, what's the point of going back to animals?" says Pharmagene cofounder Gordon Baxter.(1)
Alternatives to Animals in Research
Comparative studies of human populations allow doctors and scientists to discover the root causes of human diseases and disorders so that preventive action can be taken. Epidemiological studies led to the discoveries of the relationship between smoking and cancer and to the identification of heart disease risk factors.(2) Conversely, tobacco company executives relied on misleading animal-based studies to deny the link between smoking and cancer as recently as 1994.(3)
Population studies demonstrated the mechanism of the transmission of AIDS and other infectious diseases and also showed how these diseases can be prevented, whereas animal studies have produced no real results in terms of preventing or treating AIDS.(4) The National Institutes of Health have reported that more than 80 HIV/AIDS vaccines that have passed animal testing have failed in human clinical trials.(5) As the associate editor of the British Medical Journal stated, "When it comes to testing HIV vaccines, only humans will do."(6)
In the course of treating patients, much has been learned about the causes of diseases and disorders. Studies of human patients using sophisticated scanning technology (e.g., MRI, fMRI, PET, and CT) have isolated abnormalities in the brains of patients with schizophrenia and other disorders.(7)
Cell and tissue culture (in vitro) studies are used to screen for anti-cancer, anti-AIDS, and other types of drugs, and they are also a means of producing and testing a number of other pharmaceutical products, including vaccines, antibiotics, and therapeutic proteins. The U.S. National Disease Research Interchange provides human tissue to scientists investigating diabetes, cancer, cystic fibrosis, muscular dystrophy, glaucoma, and other human diseases. In vitro genetic research has isolated specific markers, genes, and proteins associated with Alzheimer's disease, muscular dystrophy, schizophrenia, and other inherited diseases. A 3-dimensional model of breast cancer has recently been developed that will allow investigators to study the earliest stages of breast cancer and test potential treatments. Rather than studying cancer in rodents, this model, which uses both healthy and cancerous human tissue, effectively allows the study of cancer as it develops in humans.(8)
Those who experiment on animals artificially induce disease; clinical investigators study people who are already ill with naturally occurring diseases or who have died. Animal experimenters want a disposable "research subject" who can be manipulated as desired and killed when convenient; clinicians must do no harm to their patients or study participants. Animal experimenters face the unavoidable fact that their artificially created "animal model" can never fully replicate the human condition, whereas clinical investigators know that the results of their work are directly relevant to people.
Alternatives to Animals in Testing
Alternatives to the use of animals in toxicity testing include replacing animal tests with non-animal methods, as well as modifying animal-based tests to reduce the number of animals used and to minimize pain and distress. Non-animal tests are generally faster and less expensive than the animal tests they replace and improve upon.
To date, several non-animal test methods have been formally validated and accepted by some countries as replacements for an existing animal test. Examples include the following:
. An embryonic stem cell test, using mouse-derived cells to assess
potential toxicity to developing embryos, has been validated as a partial
replacement for birth-defect testing in rats and rabbits.(9)
. The 3T3 Neutral Red Uptake Phototoxicity Test uses cells grown in culture to assess the potential for sunlight-induced ("photo") irritation to the skin.
. Human skin model tests are now in use, including the validated EpiDermT test, which has been accepted almost universally as a total replacement for skin corrosion studies in rabbits.(10)
. The use of human skin leftover from surgical procedures or donated cadavers can be used to measure the rate at which a chemical is able to penetrate the skin.
. Microdosing can provide information on the safety of an experimental drug and how it is metabolized in the body by administering an extremely small one-time dose that is well below the threshold necessary for any potential pharmacologic effect to take place.(11)
While effective non-animal test methods become more and more numerous, animal-based toxicology remains, as researcher Thomas Hartung wrote, "frozen in time, using and accepting the same old animal models again and again, often without stringent examination of their validity."(12)
1) Andy Coghlan, "Pioneers Cut Out Animal Experiments," New Scientist 31 Aug. 1996.
2) Christopher Anderegg et al., "A Critical Look at Animal Experimentation," Medical Research Modernization Committee, 2002.
3) Stanton Glantz, "A Selection of OSHA Comments on Lung Cancer," Tobacco.org, last accessed 14 May 2009.
4) Samuel Baron, M.D., et al., Medical Microbiology, 4th ed., University of Texas: Churchill Livingstone Inc., 1996.
5) National Institute of Allergy and Infectious Diseases, "Clinical Trials of HIV Vaccines," National Institutes of Health, 19 Sept. 2008.
6) Alison Tonks, "Quest for the AIDS Vaccine," British Medical Journal 334 (2007): 1346-8.
7) Kelvin O. Lim et al., "In Vivo Structural Brain Assessment," The American College of Neuropsychopharmacology, 2000.
8) Michael Balls, "The Use of Scientifically-Validated In Vitro Tests for Embryotoxicity," European Centre for the Validation of Alternative Methods, 3 June 2002.
9) Deborah L. Holliday et al., "Novel Multicellular Organotypic Models of Normal and Malignant Breast: Tools for Dissecting the Role of the Microenvironment in Breast Cancer Progression," Breast Cancer Research," 11 (2009): R3.
10) Michael Balls, "Statement on the Application of the EpidermT Human Skin Model for Skin Corrosivity Testing," European Centre for the Validation of Alternative Methods, 21 Mar. 2000.
11) Center for Drug Evaluation and Research (CDER). Guidance for Industry, Investigators, and Reviewers: Exploratory IND Studies, Rockville, Md.: CDER, 2006.
12) Marcel Leist et al., "The Dawning of a New Age of Toxicology," ALTEX 25 (2008): 102.