Telomeres, chromosomal caps that promote genetic stability, naturally shorten with each cellular replication: shorter telomeres are associated with greater biological age. In the new work, Elissa S. Epel of the University of California at San Francisco and her colleagues studied healthy premenopausal women to investigate the link between psychological stress and telomere shortening. For the high-stress group, the researchers recruited 39 mothers of chronically ill children and compared them to control women who had healthy children. In a questionnaire, mothers with sick children reported that they were more stressed compared to mothers with healthy children. When the scientists obtained cell samples and compared stress levels to telomere length, they found correlations between the length of caregiving (and thus stress levels) and cellular aging. According to the report, women who felt more stressed had cells with shorter telomeres, lower levels of the associated enzyme telomerase, and greater levels of oxidative stress.
"The new findings suggest a cellular mechanism for how chronic stress may cause premature onset of disease," Epel says. "Chronic stress appears to have the potential to shorten the life of cells, at least immune cells." The team plans to continue its investigation of the connection between stress and telomere length with a long-term study that repeatedly measures the variables over time instead of taking a single snapshot. In addition, the researchers intend to try to determine whether prolonged stress impacts telomeres in other types of cells, such as those that line the cardiovascular system.