Telomeres and aging

Telomere length is often considered a biological marker for aging and has been linked to cell lifespan, as well as certain diseases. Here we take a closer look at the relationship between telomeres and aging.

What is a telomere?

A telomere is a repetitive chain of DNA repeats found on the end of our chromosomes.

Telomeres act as a buffer, protecting the important coding DNA during replication and cell division. With each division a number of these repeats are lost, meaning that the telomere shortens.

When the number of DNA repeats is critically low, mechanisms will be triggered to halt cell division – this is known as cellular senescence. Telomeres, therefore, give somatic cells a finite lifespan.

This can be considered a protective mechanism. If the cell continued dividing, when the telomeres were not sufficient to protect the genetic integrity of the cell, the resulting instability could allow tumor growth.

How do telomeres relate to aging?

As progressive shortening of telomeres leads to cellular senescence, cell death (apoptosis), or tumor growth; telomere length can, over time, affect the health and lifespan of an individual.

As the number of senescent cells in the body increases this can be considered aging at a biological level. Telomeres can be thought of as a biological clock, determining the lifespan of cells and playing a part in the lifespan of organisms.

Shorter telomeres have been associated with increased incidence of diseases and in some specific cases worse outcomes and survival. For example, idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD).

Telomere biology disorders (TBDs), for example dyskeratosis congenita, are sometimes considered premature aging conditions. Read more about TBDs here.

Telomeres shortening over the course of our lives could contribute to the increased incidence of cancer in older adults.

Can you lengthen telomeres and slow aging?

There have been studies into certain lifestyle factors that may be linked to accelerated telomere shortening. This may adversely affect health and lifespan.

It is important to note that there is a relatively large range of ‘normal’ telomere lengths for each age group. This level of variance explains why when reporting telomere length results, we only class ‘very low’ telomere length as those below the 1^st percentile for age.

Telomere length analysis has been the object of keen interest as a way of providing personal biological aging information.

However, to date this has not been studied in case-controlled clinical studies that are necessary to define interpretation of the results for individuals.

For more information on recent and current areas of telomere research, including how you can get in touch, head to this section of our website.

Sources

Gilley D., Tanaka H., and Herbert B, S. Telomere dysfunction in aging and cancer. Int J Biochem Cell Biol. 2005 May;37(5):1000-13. doi: 10.1016/j.biocel.2004.09.003. PMID: 15743674.

Greenwood M, J. and Lansdorp P, M. Telomeres, telomerase, and hematopoietic stem cell biology. Arch Med Res. 2003 Nov-Dec;34(6):489-95. doi: 10.1016/j.arcmed.2003.07.003. PMID: 14734088.

Shammas, M. A. Telomeres, lifestyle, cancer, and aging. Current opinion in clinical nutrition and metabolic care. vol. 14,1 (2011): 28-34. doi:10.1097/MCO.0b013e32834121b1.

Shin, J,S. et al. The role of telomeres and telomerase in the pathology of human cancer and aging. Pathology. 2006. Apr;38(2):103-13. doi: 10.1080/00313020600580468. PMID: 16581649.