Conclusions

The social and economic costs of amyotrophic lateral sclerosis, Alzheimer's disease, Huntington's chorea, and Parkinson's disease are considerable. Given that resources are limited, wise use of available research funds increases the likelihood of ameliorating the negative effects of these diseases.

This study found that the animal models designed to improve our understanding and treatment of these conditions have had little impact, and their future value is highly dubious. Animal models of degenerative neurological diseases do not merit the enthusiastic support they currently receive among animal researchers or funding agencies.

For each of the four diseases, a better understanding of etiology is a critical clinical issue. Such information would assist preventive and treatment strategies. The animal models, which involve artificially induced conditions and have fundamentally different etiopathologies from the analogous human diseases, appear to have been of little use. Insights are more likely to come from clinical investigations, whose potential has been enhanced by recently developed methods employing advanced technology.

Advances in epidemiology, largely due to computerized data processing, may help identify risk factors for the development of the degenerative neurological diseases. Risk factors may, in turn, elucidate these conditions’ underlying causes.

Non-invasive imaging devices, such as CAT, MRI, and PET scans, permit safe study of ongoing disease processes. These tests can identify subtle changes in CNS structure and function.

Post-market surveillance of drugs may serendipitously reveal clinical efficacy of some drugs for the management of neurological diseases. Robinson and Kurtz have written:

The potential of serendipity cannot be overlooked when evaluating treatment strategies. Throughout the history of medicine, there are examples of a significant advance coming about as a result of careful clinical monitoring of a drug that was supposed to do something else but had an effect in an unpredicted direction.. . . Perhaps there exists a drug available today that when looked at with the proper perspective would shed light on new and effective treatment strategies of AD.(1)

Finally, in vitro research will likely help determine toxicity of endogenous and exogenous substances at concentrations that are more physiological than the concentrations that occur when these substances are injected into local regions of the brains of laboratory animals.

Appropriate use of scarce research funds is an important public health issue. Based on the findings of this review, as well as other analyses of animal models,(2-5) we recommend that funding agencies take a closer look at the value of all animal models of human diseases.

References

1. Robinson DS, Kurtz NM: A scientific and pharmacological industry perspective, in Crook T, Bartus R, Ferris S, Gershon S (eds): Treatment Strategies for Alzheimer's Disease. New York; Mark Powley, 1986.

2. Kaufman SR, Reines BP, Casele H, Lawson L, Lurie J: An evaluation of ten randomly chosen animal models of human disease. Perspec An Res 1989;1S:1-131.

3. Reines BP: A critique of animal psychology research at the University of California at Berkeley. Perspec An Res 1989;1:25-55.

4. Wiebers DO, Adams HP, Whisnant JP: Animal models of stroke: Are they relevant to human disease? Stroke 1990;21:1-3.

5. Sperlinger D (ed): Animals in Research.- New Perspectives in Animal Experimentation. New York, John Wiley & Sons, 1981.

Acknowledgements

We would like to thank the Physicians Committee for Responsible Medicine whose summer fellowship program helped make this project possible. We also thank Joan Dunayer and Rhoda Karp for their editorial assistance.

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