The aging process has been linked to the occurrence of chronic diseases and functional impairments, including cancer, sarcopenia, frailty, metabolic, cardiovascular, and neurodegenerative diseases. Nonetheless, aging is highly variable and heterogeneous and represents a challenge for its characterization. In this sense, intrinsic capacity (IC) stands as a novel perspective by the World Health Organization, which integrates the individual wellbeing, environment, and risk factors to understand aging. However, there is a lack of quantitative and qualitative attributes to define it objectively. Therefore, in this review we attempt to summarize the most relevant and promising biomarkers described in clinical studies at date over different molecular levels, including epigenomics, transcriptomics, proteomics, metabolomics, and the microbiome. To aid gerontologists, geriatricians, and biomedical researchers to understand the aging process through the IC. Aging biomarkers reflect the physiological state of individuals and the underlying mechanisms related to homeostatic changes throughout an individual lifespan; they demonstrated that aging could be measured independently of time (that may explain its heterogeneity) and to be helpful to predict age-related syndromes and mortality. In summary, we highlight the areas of opportunity and gaps of knowledge that must be addressed to fully integrate biomedical findings into clinically useful tools and interventions.

衰老过程与慢性疾病和功能障碍的发生有关，包括癌症，肌肉减少症，虚弱，代谢，心血管和神经退行性疾病。然而，老化是高度可变的并且是异质的，并且对其表征提出了挑战。从这个意义上说，内在能力（IC）是世界卫生组织（World Health Organization）的一个新颖观点，该组织整合了个人的健康，环境和风险因素以了解衰老。但是，缺乏定量和定性的属性来客观地对其进行定义。因此，在这篇综述中，我们试图总结迄今为止在不同分子水平上临床研究中描述的最相关和最有前途的生物标记物，包括表观基因组学，转录组学，蛋白质组学，代谢组学和微生物组。帮助老年病学家，老年病学家和生物医学研究人员通过IC了解衰老过程。老化的生物标志物反映了个体的生理状态以及在整个生命周期中与体内稳态变化相关的潜在机制；他们证明了可以独立于时间来测量衰老（这可以解释其异质性），并且有助于预测与年龄有关的综合征和死亡率。总之，我们重点介绍了将生物医学发现完全整合到临床有用的工具和干预措施中必须解决的机会和知识领域。