Telomere length has long been considered to play an important role in ageing and disease. Longer telomeres are associated with aging well, while shorter telomeres are associated with increased risk of age-related diseases and mortality.
But so far, most studies investigating the telomere length and aging relationship have focused solely on our blood cells, but is this actually representative of telomere length in other tissues? And therefore, do all our organs and tissues age at the same rate?
The answer has important implications for the study of telomeres in age-related disease.
In the study, the scientists took advantage of the Genotype-Tissue Expression (GTEx) project, a massive public resource focused on collecting samples from many different tissues from hundreds of human subjects.
The researchers used a new type of assay for measuring telomere length, comparable in cost to traditional methods but with “higher throughput and better precision,” according to study co-author Muhammad Kibriya, MD, PhD, Research Associate Professor at the Institute for Population and Precision Health at UChicago. By analyzing more than 6,000 tissue samples across over 20 tissue types and nearly 1,000 unique post-mortem human subjects, Kibriya said, “We were able to find statistically significant tissue-to-tissue differences in telomere length within the sample set.”
They found that out of the 23 tissues they studied, telomere length in 15 tissues showed a clear, positive correlation with telomere length in whole blood cells, supporting the use of easily collected whole blood cell telomere length as a proxy for telomere length in harder-to-access tissues, like brain and kidney.
Interestingly, some relationships involving telomere length that have been established in blood cells did not hold true in other tissues:
Some patterns held up across different tissues, like shorter telomeres in aging, and longer telomeres in people of African ancestry, but others didn’t, like longer telomeres in females. We observed shorter telomeres among smokers in only a few tissues.”