Non-animal
methods have more predictive value and specificity for the human condition than
do animal methods, which rely on different species with different anatomies and
physiologies. In one head-to-head comparison, the Multicentre Evaluation of
In-Vitro Cytotoxicity (MEIC) evaluated 68 different methods to predict toxicity
for 50 different chemicals. The animal tests were at best 65 percent predictive
of human toxicity, while human tests were predictive more than 80 percent of
the time.
Non-animal tests include:
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In vitro (test-tube) research
Cell and tissue cultures are powerful investigative tools. Cell and tissue
cultures can be used to screen new therapies and to test for product safety. In
fact, human tissues could have predicted the catastrophic reaction to the drug
TGN1412 in a clinical trial in London
in 2006.
Microfluidic circuits provide the nearest thing to a human body on a chip. They
comprise tiny channels with cells from various human organs and are linked by a
circulating blood substitute. Using these circuits, new drugs can be tested on
a “whole system” where they encounter human cells in the same order as they
would encounter them in the human body. Sensors in the chip then feed back
information for computer analysis.
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In silicon or computer modeling
Computer modeling is so sophisticated that scientists can simulate in silico in
minutes or hours experiments that would take months or years in animals. Drugs
can be designed on computers and then tested on virtual organs or in virtual
clinical trails.
This exciting new field is based on the principle that the best model for a man
is man. Human microdosing relies on ultra-sensitive analytical techniques and
permits the safe introduction of miniscule doses of new drugs into subjects in
order to evaluate drug activity in the human body.
Epidemiological studies of human populations contribute greatly to our
understanding of human health and medicine. Such studies have shown the links
between tobacco and lung cancer, between cholesterol and heart disease, between
high blood pressure and stroke, and between toxins and birth defects.
Clinical research is the direct study of human disease through the close
monitoring of human patients. For example, clinical studies have shown how a
low-fat vegetarian diet can treat heart disease and diabetes. Sophisticated
scanning technologies, such as MRI and PET scans, have allowed scientists to
“see” abnormalities—and track treatment progress—in the brains of people with
epilepsy, schizophrenia, and other diseases.
Why do researchers still use animals with so many excellent
alternatives available? Although there is a growing use of replacements in some
fields, it’s clear that inertia, tradition, and a lack of will plague many U.S. scientists
and the regulatory agencies that oversee them. Most important, current U.S. regulatory
practices often require the use of animals for drug, chemical, and device
approvals. (Animal tests are not required for basic research.) An international
coalition of organizations is calling on the Food and Drug Administration to
mandate alternatives when available.