Jazwinski S Michal, Kim Sangkyu
Tulane Center for Aging, Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA, United States.
Front Genet. 2019 Mar 26;10:263. doi: 10.3389/fgene.2019.00263. eCollection 2019.
The concept of biological age has been used more and more frequently in aging research in attempts to measure the progress of the biological aging process as opposed to the simple passage of time. Several approaches to quantify biological age have been utilized, including the use of biomarkers in the form of serum analytes, epigenetic markers, and deficit or frailty indices. Among these methods, the deficit index possesses a theoretical basis grounded in systems biology by incorporating networks, with their emergent properties, to describe the complex aging system. Application of the deficit index in human aging studies points to the increased energetic demands posed by an aging system that is losing integration. Different aspects of mitochondrial function appear to be responsible in males and females. The gut microbiome loses complexity in tandem with the host, as biological age increases, with likely impact on host metabolism and immunity. Specific DNA methylation changes are associated with biological age. They suggest declining connectivity within the aging network, at the cellular level. The deficit/frailty index may account for at least part of the departure at older ages of the observed mortality in the population from the exponential increase modeled by the Gompertz equation.
生物年龄的概念在衰老研究中使用得越来越频繁，旨在衡量生物衰老过程的进展，而非仅仅是时间的流逝。已经采用了几种量化生物年龄的方法，包括使用血清分析物、表观遗传标记以及缺陷或衰弱指数等形式的生物标志物。在这些方法中，缺陷指数具有基于系统生物学的理论基础，通过纳入具有涌现特性的网络来描述复杂的衰老系统。缺陷指数在人类衰老研究中的应用表明，衰老系统失去整合会带来能量需求的增加。线粒体功能的不同方面似乎在男性和女性中发挥着不同作用。随着生物年龄的增加，肠道微生物群与宿主同步失去复杂性，这可能会影响宿主的新陈代谢和免疫力。特定的DNA甲基化变化与生物年龄相关。它们表明在细胞水平上，衰老网络内的连通性正在下降。缺陷/衰弱指数可能至少部分解释了在老年时观察到的人群死亡率偏离由冈珀茨方程建模的指数增长的现象。
