International Association Against Painful Experiments on Animals

Human Tissue - Alternative to Animal Testing Experiments

9: Animal Experiments have Serious Limitations

Fortunately, some researchers are beginning to recognize that animal experiments have serious limitations. In 1987 the scientific journal Trends in Pharmacological Sciences stated that "direct extrapolation from animals to humans is frequently invalid" and noted that "recently much interest has focused on use of human autopsy or biopsy tissue as a means of overcoming these limitations."(24) An example is the use of diseased human heart muscle preparations from patients who have died. Researchers at Hamburg's . Universität-Krankenhaus Eppendorf and the University ät Munchen argue that such tissue is useful in evaluating certain heart drugs and may also provide new insights into the nature of heart disease.(25) The preference for human cardiac tissue is shared by scientists at Stanford University and the School of Medicine at the University of Utah who have studied the chemical changes that occur in cardiac tissue during heart failure. Only human material can provide accurate results because of species differences in the type and proportion of the all-important tissue chemicals known as receptors.(26)

It has even proved possible to study beating human heart cells. Researchers from the Children's Hospital of Winnipeg and the Department of Pediatrics at the University of Manitoba state that "although numerous in vitro studies have been done on beating cardiac tissue and cells from experimental animals, there has been a surprising paucity of similar work with human material." During chromosome studies with tissue from early human spontaneous abortions, they found isolated heart cells maintaining a rhythmic beat in tissue culture. Pulsation continued for up to 88 days allowing heart drugs and body chemicals to be tested for their effects. As expected from their action in a living person, adrenaline increased pulsation rate while addition of the heart drug propranolol slowed the rate.(27)

Pharmacologists have used many other human tissues for their research. Professor Schrör of the University of Dusseldorf and Raphaela Verheggen at the University of Göttingen argue that human cerebral blood vessels, obtained within 24 hours of death, provide a valuable means of studying cerebral vasospasm, a condition in which blood vessels in the brain constrict, with fatal results for patients with subarachnoid hemorrhage. Little is known about how to treat cerebral vasospasm because the underlying chemical processes are poorly understood. The German researchers refer to considerable species variations in animal models and conclude that much needed improvements in treatment can be expected from human tissue studies.(20) Another example is the use of lung tissue to investigate asthma and related conditions. The tissue is obtained from patients undergoing surgery for lung disease. When treated with the bronchodilator drugs used to treat asthma, the tissue is "relaxed" as would be expected in patients receiving treatment. On the other hand, bronchoconstrictor drugs make the tissue constrict.(28)

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