Animal Models of Degenerative Neurological Diseases
Stephen R. Kaufman, Todd Czarnecki, Irene Haralabatos, Mollette Richardson
Introduction
Few conditions are more feared than the degenerative neurological diseases. Slowly, patients suffer progressive loss of muscle and/or mental function. As the victims become incapacitated, they can become major financial and psychological burdens to the family. The medical and social consequences of degenerative neurological diseases create strong incentives to improve the management of these conditions. Research is certainly one component of the treatment strategy. Extensive animal research has focused on the four degenerative neurological diseases reviewed in this study -- amyotrophic lateral sclerosis, Alzheimer's disease, Huntington's chorea, and Parkinson's disease. But is such research the most efficient and effective way to increase our understanding of the diseases and to discover better therapies? Given the massive public and private funding of animal models of degenerative neurological diseases, such research must be carefully and critically examined.
Funding agencies have, in general, been enthusiastic supporters of animal research. For example, the Parkinson's Disease Foundation recently wrote:
All of us who are concerned with the problem of people living with Parkinson's know that improvements in treatment come following research on animal models of the disease. . . . What if animal research were halted today? . . . Researchers would be unable to clarify the cause of Alzheimer's disease. Without that knowledge, the prognosis for the 3 million Alzheimer's victims would remain bleak.(1)
Several organizations devoted to the management of degenerative neurological diseases have formed coalitions to promote animal research. The Amyotrophic Lateral Sclerosis Association, Huntington's Disease Society of America, Parkinson's Disease Foundation, and United Parkinson Foundation were among 52 health organization signatories to a statement endorsing animal research. The statement read, in part, "While great strides have been made in the understanding, prevention, and treatment of diseases, there still is much to be learned. Much of that research relies on laboratory animals."(2)
Given that research funding is limited, such blanket endorsements of animal research appear uncritical at best. It is important to evaluate the likely future contributions from animal models of these diseases.
In our effort to assess the value of the animal models, we used three criteria. First, how well do the clinical presentation and pathogenesis of each animal model conform to the analogous human disease? Second, to what extent do clinicians (as evidenced by recent review articles in the clinical literature) attribute significant contributions to the animal models and expect such models to be useful in the future? Third, how well do animal models address the critical clinical issues that need clarification in order to improve the management of the diseases?
References
1. Parkinson's Disease Foundation: Animal research. Parkinson's Disease Foundation Newsletter, Spring 1989, p 4.
2. Statement of national and voluntary health organizations, April 26, 1989.