Telomeres Tell of Stress

Telomeres are the end caps of chromosomes, protecting the DNA complexes from deterioration during cell division. Telomere shortening is considered a marker of cellular aging, and prematurely shortened telomeres have been linked to increased risk of cancers, heart disease, dementia and death.  Andrew Steptoe, from University College London (United Kingdom), and colleagues enrolled 333 healthy men and women, ages 54 to 76 years, and divided them into three groups: those with longer telomeres, those with shorter telomeres and low telomerase (TA) activity, and those with shorter telomeres and high TA activity. All subjects were given tasks designed to cause psychological stress.  When they performed the tasks, all the subjects experienced an increase in heart rate and blood pressure. Their levels of cortisol, a stress hormone, also rose. However, once the task was completed, some men found it easier to recover and return to normal conditions than other men. Men with longer telomeres had quicker recovery times than men with shorter telomeres. Men with shorter telomeres and low TA activity had quicker recovery times than men with shorter telomeres and high TA activity.  Psychological testing showed that men in the short telomere/high TA group were more hostile and less optimistic than other men. They also had less social support. The researchers think these men found it harder to recover from stress because they were carrying a high allostatic load: chronic stress had caused the their regulatory processes to become disturbed.  The study authors submit that their data “documents the dynamic interplay between social environmental exposures and the mechanisms underlying chromosomal integrity.”