Van Bodegom David, May Linda, Meij Hans J, Westendorp Rudi G J
Department of Geriatrics and Gerontology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands.
Ann N Y Acad Sci. 2007 Apr;1100:84-97. doi: 10.1196/annals.1395.007.
Most species with a long life span have few offspring while species with a short life span have many offspring. This evolutionary trade-off between fertility and body maintenance, based on the theory of r/K-selection, is a central theme in the theory of life history regulation. This trade-off is not only found between various species but also between individuals within one species. There is accumulating evidence for this trade-off in humans. We hypothesize that the innate immune system is a critical factor skewing an individual into the direction of either a high fertility or better maintenance strategy. As over thousands of years human survival has been highly dependent on resistance to infectious diseases, genetic adaptations resulting in inflammatory responses were favored. An inflammatory host response is critical to fight infection necessary to survive up to reproductive age. An inflammatory host response is also negatively associated with fertility and can explain for the trade-off between fertility and body maintenance. After human reproductive age, these inflammatory responses contribute also to development of chronic degenerative diseases. These will especially become apparent in affluent societies where the majority of individuals reach old age. Identifying the inflammatory host response as a critical factor both in the regulation of human life histories and in the occurrence of chronic diseases at old age implies means for intervention allowing individuals to live healthier for longer.
大多数寿命长的物种后代较少，而寿命短的物种后代较多。基于r/K选择理论，这种生育力与身体维持之间的进化权衡是生命史调节理论的核心主题。这种权衡不仅存在于不同物种之间，也存在于同一物种的个体之间。在人类中，这种权衡的证据越来越多。我们假设，先天免疫系统是使个体偏向高生育力或更好维持策略方向的关键因素。由于数千年来人类的生存高度依赖于对传染病的抵抗力，导致炎症反应的基因适应受到青睐。炎症性宿主反应对于对抗活到育龄所需的感染至关重要。炎症性宿主反应也与生育力呈负相关，并且可以解释生育力与身体维持之间的权衡。在人类生殖年龄之后，这些炎症反应也会导致慢性退行性疾病的发展。这在大多数个体都能活到老年的富裕社会中尤其明显。将炎症性宿主反应确定为人类生命史调节和老年慢性病发生的关键因素，意味着有干预手段可以让个体活得更健康、更长久。
