Copyright 1992 by The Gerontological Society of America
Editorials
The Gerontologist Vol. 32, No. 5, 580-582
ANIMAL STUDIES ARE TEACHING US ABOUT AGING
T. Franklin Williams, MD
The University of Rochester and Monroe Community Hospital Rochester, NY References Cristofalo, V. J., & Lawton, M. P. (Eds.). (1990). Special focus on the biology of aging. Annual Review of Gerontology and Geriatrics, 10, New York: Springer. Finch, C. E. (1990). Longevity, senescence and the human genome. Chicago: University of Chicago Press. Masoro, E. J. (1992). The role of animal models in meeting the gerontologic challenge of the twenty-first century. The Gerontologist, 32, xxx-xxx. Williams, T. F., Sprott, R. L, & Warner, H. R. (Eds.). (1992). Biology of aging. [Special issue]. Generations, 76(4).
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The Gerontologist
Downloaded from http://gerontologist.oxfordjournals.org/ at University of Michigan on September 6, 2015
cal, and social aspects of aging. Not only does "a healthy body support a healthy mind," as one may see in Masoro's dietary restricted rodents. Some studies also offer evidence for the deleterious effect of stress such as social isolation on brain function, perhaps through stimulation of stress hormones such as adrenocortical hormones. The differences between aging phenomena and diseases are discussed. And in the many aspects of the biology of aging, the same considerable variability between individuals appears that we see in psychological and social aspects of aging. In my judgment, the major challenge in all arenas of aging research today is to seek the explanations for the variations among individuals: why, in almost every study of almost every sphere, are there some old individuals whose characteristics for the phenomenon being studied are equivalent of typical younger individuals, even if there are significant changes on average, old compared to young? Finally, we should all take to heart Dr. Masoro's concern that poorly informed views about the use of animals in biologic (and psychological and social) research may threaten the proper use of animals in such research. As he points out in his own research, great care can be and is given to assuring healthful care. There is no need nor place for painful intervention. In fact, it is especially important in conducting animal studies of aging changes that animals be maintained in a fully active, healthful life-style. The interpretations of many past studies can be questioned on the grounds that the aging animals had not been really "normally healthful," but rather were the rodent equivalent of "couch potatoes." The results of animal studies often bring insights into the healthful aging of animals, as well as making enormous and otherwise unobtainable contributions to understanding human aging. I hope that we can all share and support his commitment to such goals.
Dr. Edward J. Masoro deserves thanks for his clear depiction, in his Kleemeier Lecture (1992), of the contributions being made and anticipated to be made, through animal research, to meeting the challenges ahead in gerontology. As he points out, and as others like Caleb Finch in his recent book (1990) have documented, we still know astonishingly little about what characterizes senescence biologically. Some organs and functions change very little with aging, others change more. Overall, there is a rather predictable lifespan for members of any species but considerable variations among the individuals within the species. In order to understand and develop explanatory theories of aging, we need, as Masoro states, "a broad spectrum of animal models." In this context Masoro and his colleagues have made contributions of major importance, through their dietary restriction model studies, to clarifying and simplifying the picture of biological aging. As he summarizes in this article, rodents who live on appropriate dietarily restricted regimens live predictably much longer than ad libitum fed animals, maintain their own protective mechanisms such as immune function, and develop common diseases like tumors and renal disease much less frequently. That is, such animals may be said to have a much "healthier" aging. In his recent studies of metabolic aspects of the effects of dietary restriction, Masoro and his colleagues have shown that such animals apparently achieve a more efficient utilization of glucose in their production of necessary energy, and in the process may reduce the production of potentially damaging free radicals. What are the implications of these incisive studies in rodents for health and senescence in humans? We cannot make any jump to grand conclusions. There are ongoing studies now in testing the effects of prudent dietary restriction in nonhuman primates; early observations show no deleterious effects, but it will obviously take years to determine any significant impacts. The rodent studies do clearly increase our understanding of mechanisms that may be damaging in the course of aging and approaches to minimize or avoid such damage. The importance of the many advances being made in understanding the biology of aging to scholars interested in all aspects of gerontology is seen in the fact that the current issue of Generations (Williams, Sprott, & Warner, 1992) is devoted to this topic. Also, the recent volume in the series of yearbooks on gerontology and geriatrics (Cristofalo & Lawton, 1990) is similarly focused. A number of the elements of biological research findings that are reviewed there reveal increasing evidence of interrelations between biological, psychologi-
Editorials
The Gerontologist Vol. 32, No. 5, 580-582
ANIMAL STUDIES ARE TEACHING US ABOUT AGING
T. Franklin Williams, MD
The University of Rochester and Monroe Community Hospital Rochester, NY References Cristofalo, V. J., & Lawton, M. P. (Eds.). (1990). Special focus on the biology of aging. Annual Review of Gerontology and Geriatrics, 10, New York: Springer. Finch, C. E. (1990). Longevity, senescence and the human genome. Chicago: University of Chicago Press. Masoro, E. J. (1992). The role of animal models in meeting the gerontologic challenge of the twenty-first century. The Gerontologist, 32, xxx-xxx. Williams, T. F., Sprott, R. L, & Warner, H. R. (Eds.). (1992). Biology of aging. [Special issue]. Generations, 76(4).
580
The Gerontologist
Downloaded from http://gerontologist.oxfordjournals.org/ at University of Michigan on September 6, 2015
cal, and social aspects of aging. Not only does "a healthy body support a healthy mind," as one may see in Masoro's dietary restricted rodents. Some studies also offer evidence for the deleterious effect of stress such as social isolation on brain function, perhaps through stimulation of stress hormones such as adrenocortical hormones. The differences between aging phenomena and diseases are discussed. And in the many aspects of the biology of aging, the same considerable variability between individuals appears that we see in psychological and social aspects of aging. In my judgment, the major challenge in all arenas of aging research today is to seek the explanations for the variations among individuals: why, in almost every study of almost every sphere, are there some old individuals whose characteristics for the phenomenon being studied are equivalent of typical younger individuals, even if there are significant changes on average, old compared to young? Finally, we should all take to heart Dr. Masoro's concern that poorly informed views about the use of animals in biologic (and psychological and social) research may threaten the proper use of animals in such research. As he points out in his own research, great care can be and is given to assuring healthful care. There is no need nor place for painful intervention. In fact, it is especially important in conducting animal studies of aging changes that animals be maintained in a fully active, healthful life-style. The interpretations of many past studies can be questioned on the grounds that the aging animals had not been really "normally healthful," but rather were the rodent equivalent of "couch potatoes." The results of animal studies often bring insights into the healthful aging of animals, as well as making enormous and otherwise unobtainable contributions to understanding human aging. I hope that we can all share and support his commitment to such goals.
Dr. Edward J. Masoro deserves thanks for his clear depiction, in his Kleemeier Lecture (1992), of the contributions being made and anticipated to be made, through animal research, to meeting the challenges ahead in gerontology. As he points out, and as others like Caleb Finch in his recent book (1990) have documented, we still know astonishingly little about what characterizes senescence biologically. Some organs and functions change very little with aging, others change more. Overall, there is a rather predictable lifespan for members of any species but considerable variations among the individuals within the species. In order to understand and develop explanatory theories of aging, we need, as Masoro states, "a broad spectrum of animal models." In this context Masoro and his colleagues have made contributions of major importance, through their dietary restriction model studies, to clarifying and simplifying the picture of biological aging. As he summarizes in this article, rodents who live on appropriate dietarily restricted regimens live predictably much longer than ad libitum fed animals, maintain their own protective mechanisms such as immune function, and develop common diseases like tumors and renal disease much less frequently. That is, such animals may be said to have a much "healthier" aging. In his recent studies of metabolic aspects of the effects of dietary restriction, Masoro and his colleagues have shown that such animals apparently achieve a more efficient utilization of glucose in their production of necessary energy, and in the process may reduce the production of potentially damaging free radicals. What are the implications of these incisive studies in rodents for health and senescence in humans? We cannot make any jump to grand conclusions. There are ongoing studies now in testing the effects of prudent dietary restriction in nonhuman primates; early observations show no deleterious effects, but it will obviously take years to determine any significant impacts. The rodent studies do clearly increase our understanding of mechanisms that may be damaging in the course of aging and approaches to minimize or avoid such damage. The importance of the many advances being made in understanding the biology of aging to scholars interested in all aspects of gerontology is seen in the fact that the current issue of Generations (Williams, Sprott, & Warner, 1992) is devoted to this topic. Also, the recent volume in the series of yearbooks on gerontology and geriatrics (Cristofalo & Lawton, 1990) is similarly focused. A number of the elements of biological research findings that are reviewed there reveal increasing evidence of interrelations between biological, psychologi-
