About this Research Topic
The ‘exposome’ proposes that exposures may jointly impact on common biological mechanisms and may overcome current limitations in identifying new causes of non-communicable diseases. In parallel, it is recognised that common pathological roots underlie multi-morbidity and that exposures throughout the life-course can have far reaching consequences on health later in life. As the greatest risk factor for nearly every major cause of mortality in developed nations, ageing itself may represent one such common biological mechanism. Ageing can be defined as the “time-dependent decline of functional capacity and stress resistance, associated with increased risk of morbidity and mortality”. Both the genome and the exposome, including physical, psychological and behavioural stressors, can influence the ageing process, leading to differing ageing rates. Therefore, a person’s “biological age”, or overall physiological state, may differ from what is expected given their chronological age.
Traditionally, quantitative assessment of “the rate of ageing” relies on the analysis of mortality curves of populations. However, at the level of a living individual, this method does not allow assessment of the state of ageing (i.e. the state of the functional decline) and a prediction of the risk of morbidity and remaining life expectancy. Therefore, markers of ‘biological age’ (the ageing state typical of one’s chronological age) that can be assessed at any point in the lifespan therefore, may have great potential in both personalised medicine and public health. Although the search for biomarkers of biological age has been ongoing for many decades, recent advances in molecular biology has allowed new breakthroughs. Ageing is a process that affects almost all tissues and organs of the body and involves cross-talk between multiple physiological systems and there has been increased research into composite markers of ageing, involving multiple parameters. While many studies have combined established clinical biomarkers to provide important insights into the ageing process, it is the use of ‘omics’, which agnostically assay whole sets of molecular features, that may prove the most promising approach. Since Horvath first proposed his ‘epigenetic clock’ that provides highly accurate age prediction based on the combined methylation levels of multiple CpG loci, there has been an explosion of research into the causes and consequences of ‘accelerated epigenetic ageing’. In parallel new multivariate biomarkers have been proposed based on transcriptomic, metabolomic and proteomic data that may provide more complete or complementary assessments of biological age.
In this research topic we aim to collate articles related to biomarkers of biological ageing. Although later life is the period where variability in biological age is at its greatest, we welcome studies in human populations at all life periods, since early-life and early adulthood are known to be important in determining subsequent ageing trajectories. We welcome research in the following areas:
• Development, validation and application of new and existing biological age biomarkers
• Risk factors and determinants of faster (or slower) biological ageing rates
• Prediction by biological age (over chronological age) of mortality, age-related disease, well-being and physical and functional end points (for example cognition, frailty or developmental staging in children)
People live longer today than ever before but often suffer from multiple diseases or disabilities. Many families struggle to care for elderly relatives who survive for years with reduced quality of life, while nations devote an increasing proportion of finite resources toward medical care for aging populations. The development of new tools to assess biological ageing is going to be critical to adequately study the process of ageing, elucidate the key factors and the mechanisms that modulate this process, and may ultimately help more people experience healthy ageing.
Keywords: ageing, biomarkers, omics, epigenetics, biological clock
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.