Readers of Life Extension Update may recall the November 29, 2004 issue which described an association between emotional stress and shortened telomeres, a marker of cellular aging. Now, in research published in the May, 2008 issue of Brain, Behavior and Immunity, a team at the University of California, Los Angeles report that they may have discovered why.
Telomeres are caps at the ends of chromosomes (the genetic material of the cell) that contribute to their stability. Each time a cell divides, telomeres lose length. Telomeres also lose length in response to chronic stress. Shortened telomeres in white blood cells known as lymphocytes have been associated with HIV, osteoporosis, heart disease and aging. An enzyme within the cell known as telomerase helps prevent telomere shortening and maintains the cells' ability to continue dividing.
For the current investigation, UCLA David Geffen School of Medicine professor of pathology and laboratory medicine Rita Effros and colleagues studied lymphocytes from healthy male and female donors between the ages of 25 and 55. The cells were treated with varying concentrations of cortisol, the hormone released by the body when under stress, or with DMSO (as a control).
After three days, cultures treated with cortisol had fewer cells than the control cultures. While treatment with a concentration of cortisol equivalent to that normally found in humans had no effect on telomerase activity, concentrations of the hormone comparable to levels found in the body under stress were demonstrated to reduce telomerase activity by up to 50 percent compared with telomerase activity measured in the control cultures.
The discovery explains how stress reduces telomerase, thereby accelerating cellular aging, via increased cortisol production. "When the body is under stress, it boosts production of cortisol to support a "fight or flight" response," Dr Effros explained. "If the hormone remains elevated in the bloodstream for long periods of time, though, it wears down the immune system. We are testing therapeutic ways of enhancing telomerase levels to help the immune system ward off cortisol's effect. If we're successful, one day a pill may exist to strengthen the immune system's ability to weather chronic emotional stress."
Related Health Concern: Anxiety
Anxiety can occur independently or in conjunction with other psychiatric or medical conditions, such as depression, phobias, chronic fatigue, cardiac disease, or respiratory compromise. Moreover, chronic anxiety is associated with a higher risk of morbidity and mortality from cerebrovascular and cardiovascular diseases, such as hypertension, cardiac ischemia, and arrhythmias, and it predisposes people to a range of other disorders (Muller JE et al 2005; Weissman MM et al 1990; Coryell W 1986, 1988). People with severe anxiety disorders who experience adverse life events such as divorce or financial disaster may be at increased risk of suicidal behavior (Allgulander C et al 1991).
Dietary L-lysine deficiency increases stress-induced anxiety (Smriga M et al 2002). In one small study, L-lysine supplementation lessened plasma cortisol in response to stress and reduced chronic anxiety (Smriga M et al 2004). L-lysine acts like a partial serotonin receptor antagonist, inhibiting neurotransmitter reuptake in the synapse (Smriga M et al 2003).
By now, it is well known that most steroid hormones (e.g., pregnenolone, estrogen, progesterone, testosterone, and DHEA) are neurologically active. In fact, large quantities of DHEA, as well as estrogen and progesterone receptors, are found in the brain. These hormones have a number of effects within the brain, including regulation of mood. Accordingly, a number of studies have linked abnormalities in hormone levels to various anxiety disorders (Birzniece V et al 2006; Cohen H et al 2006; Strous RD et al 2006). In addition, studies have documented that abnormalities in the hypothalamic-pituitary-adrenal axis, which controls the body's response to stress through the release of cortisol and DHEA, can predispose a person to anxiety and depression (Leonard BE 2005). During times of stress and anxiety, the balance between cortisol and DHEA is altered in favor of cortisol.
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