Telomeres shorten at equivalent rates in somatic tissues of adults.
Ontology highlight
ABSTRACT:
SUBMITTER: Daniali L
PROVIDER: S-EPMC3615479 | biostudies-other | 2013
REPOSITORIES: biostudies-other
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Project description:Oxidative stress shortens telomeres in cell culture, but whether oxidative stress explains variation in telomere shortening in vivo at physiological oxidative stress levels is not well known. We therefore tested for correlations between six oxidative stress markers and telomere attrition in nestling birds (jackdaws Corvus monedula) that show a high rate of telomere attrition in early life. Telomere attrition was measured between ages 5 and 30 days, and was highly variable (average telomere loss: 323 bp, CV = 45%). Oxidative stress markers were measured in blood at age 20 days and included markers of oxidative damage (TBARS, dROMs and GSSG) and markers of antioxidant protection (GSH, redox state, uric acid). Variation in telomere attrition was not significantly related to these oxidative stress markers (|r| ≤ 0.08, n = 87). This finding raises the question whether oxidative stress accelerates telomere attrition in vivo The accumulation of telomere attrition over time depends both on the number of cell divisions and on the number of base pairs lost per DNA replication and, based on our findings, we suggest that in a growing animal cell proliferation, dynamics may be more important for explaining variation in telomere attrition than oxidative stress.
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Project description:The length of telomeres, the protective caps of chromosomes, is increasingly used as a biomarker of individual health state because it has been shown to predict chances of survival in a range of endothermic species including humans. Oxidative stress is presumed to be a major cause of telomere shortening, but most evidence to date comes from in vitro cultured cells. The importance of oxidative stress as a determinant of telomere shortening in vivo remains less clear and has recently been questioned. We, therefore, reviewed correlative and experimental studies investigating the links between oxidative stress and telomere shortening in vivo While correlative studies provide equivocal support for a connection between oxidative stress and telomere attrition (10 of 18 studies), most experimental studies published so far (seven of eight studies) partially or fully support this hypothesis. Yet, this link seems to be tissue-dependent in some cases, or restricted to particular categories of individual (e.g. sex-dependent) in other cases. More experimental studies, especially those decreasing antioxidant protection or increasing pro-oxidant generation, are required to further our understanding of the importance of oxidative stress in determining telomere length in vivo Studies comparing growing versus adult individuals, or proliferative versus non-proliferative tissues would provide particularly important insights.
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