| 英文摘要 |
Taiwan will be a super-aged society by 2026. The demand for long-term care in conjunction with the wide variation in the physical and financial conditions of the individual elderly result in a very serious societal problem. Especially since we have yet to fully understand the biological aspects of aging. Thus, we briefly discuss the ‘whys’ and ‘hows’ of aging in terms of theories developed in evolutionary biology and physiological processes for aging; respectively. Aging arises as a result of a declining pressure to maintain long-lasting physiological functions, thus allowing the accumulation of mutations that exert negative effects during late stages of life. This forms the basis for the Mutation Accumulation Hypothesis. Conversely, the Antagonistic Pleiotropy Hypothesis describes a mutation that is beneficial during early life but exerts negative effects in late life. The tradeoff between reproduction and survival is considered in the Disposable Soma Hypothesis. Two main categories of theories have been proposed for the aging process: In Program Theory aging follows a biological timetable under the guidance of a genetic program while Damage (or Error) Theory follows environmental assaults that cause physiological damages to accumulate and eventually result in loss of function and thus aging. In general, the evolutionary theories do not exclude each other and have received support from genetic studies. The physiological theories, however, are less in agreement. Recent studies in the Free Radical Oxidative Stress Hypothesis have made significant progress in the understanding of cellular aging pathways or senescence. These efforts may lead to further understanding of the aging processes. |
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