Roubenoff R
Body Composition Laboratory, USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111.
J Nutr. 1993 Feb;123(2 Suppl):469-73. doi: 10.1093/jn/123.suppl_2.469.
Loss of lean body mass (LBM) is a hallmark of aging and of acute and chronic illness. Loss of more than 40% of lean mass is not compatible with life. The causes of loss of LBM in aging remain obscure, although changes in growth hormone production, physical activity and the cytokines interleukin-1 beta and tumor necrosis factor-alpha may play a role. The usefulness of a disease model based on rheumatoid arthritis (RA) is considered, in which all these changes occur to a greater degree and independently of age. RA is a common autoimmune condition in which cytokine production is increased, LBM is reduced and mortality is greatly accelerated. These observations suggest that, with respect to body composition at least, RA represents a model of "accelerated" aging. A hypothesis is presented that unifies metabolic and immunologic observations and changes in body composition. The interrelationship of the immune system and body composition is an important area that deserves further investigation.
瘦体重（LBM）的丧失是衰老以及急慢性疾病的一个标志。瘦体重丧失超过40%则无法维持生命。衰老过程中LBM丧失的原因仍不清楚，尽管生长激素分泌、身体活动以及细胞因子白细胞介素-1β和肿瘤坏死因子-α的变化可能起了一定作用。人们考虑了一种基于类风湿关节炎（RA）的疾病模型的效用，在该模型中，所有这些变化的程度更大且与年龄无关。RA是一种常见的自身免疫性疾病，其中细胞因子分泌增加，LBM减少，死亡率大幅加速。这些观察结果表明，至少就身体组成而言，RA代表了一种“加速”衰老的模型。本文提出了一个统一代谢、免疫观察结果以及身体组成变化的假说。免疫系统与身体组成之间的相互关系是一个值得进一步研究的重要领域。
