Article

Is Telomere Length a Biomarker of Aging? A Review

Centre for Mental Health Research, Australian National University, Canberra, Australia.
The Journals of Gerontology Series A Biological Sciences and Medical Sciences (Impact Factor: 5.42). 10/2010; 66(2):202-13. DOI: 10.1093/gerona/glq180
Source: PubMed

ABSTRACT

Telomeres, the DNA–protein structures located at the ends of chromosomes, have been proposed to act as a biomarker of aging.
In this review, the human evidence that telomere length is a biomarker of aging is evaluated. Although telomere length is
implicated in cellular aging, the evidence suggesting telomere length is a biomarker of aging in humans is equivocal. More
studies examining the relationships between telomere length and mortality and with measures that decline with “normal” aging
in community samples are required. These studies would benefit from longitudinal measures of both telomere length and aging-related
parameters.

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    • "The aging process is complex with significant changes in many different molecules, and some of these molecules can be used as aging indicators (Menni et al., 2013). Several aging markers have been identified , such as telomere length, reactive oxygen species levels, and caveolin-1 expression status (Cho et al., 2004; Mather et al., 2011; Pandey and Rizvi, 2010). "
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    • "As many authors have acknowledged, understanding the factors driving among-and within-individual variation in LTL demands longitudinal collection of samples across the entire lifespan of the organism in question (e.g. Aviv, 2008; Mather et al., 2011; Benetos et al., 2013). Our own species' long and continually extending life expectancy means such data sets are currently unavailable, and it remains unclear to what degree telomere dynamics measured in "
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    ABSTRACT: Telomeres play a fundamental role in the maintenance of genomic integrity at a cellular level, and average leukocyte telomere length (LTL) has been proposed as a biomarker of organismal aging. However, studies tracking LTL across the entire life course of individuals are lacking. Here, we examined lifelong patterns of variation in LTL among four birth cohorts of female Soay sheep (Ovis aries) that were longitudinally monitored and sampled from birth to death. Over the first 4 months of life, there was within-individual loss of LTL, consistent with findings in the human and primate literature, but there was little evidence of consistent LTL loss associated with age after this point. Overall, we observed only weak evidence of individual consistency in LTL across years and over the entire lifespan: Within-individual variation was considerable, and birth cohorts differed markedly in their telomere dynamics. Despite the high levels of LTL variation within the lifetimes of individuals, there remained significant associations between LTL and longevity. Detailed analysis of the longitudinal data set showed that this association was driven by improved survival of individuals with longer LTL over the first 2 years of life. There was no evidence that LTL predicted survival in later adulthood. Our data provide the first evidence from a mammal that LTL can predict mortality and lifespan under natural conditions, and also highlight the potentially dynamic nature of LTL within the lifetimes of individuals experiencing a complex and highly variable environment.
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