September 6, 2008 Stress is a function of our primal origins. When the body is under stress, it boosts production of cortisol to support the 'fight or flight' response we all have at the heart of our operating system. If the hormone remains elevated in the bloodstream for long periods of time, though, it wears down the immune system. Every cell contains a tiny clock called a telomere, which shortens each time the cell divides. Short telomeres are linked to a range of human diseases, including HIV, osteoporosis, heart disease and aging. Previous studies have shown that an enzyme within the cell, called telomerase, keeps immune cells young by preserving their telomere length and ability to continue dividing. UCLA scientists have found that the stress hormone cortisol suppresses immune cells' ability to activate their telomerase. This may explain why the cells of persons under chronic stress have shorter telomeres.

The research was published in the May 2008 issue of the peer-reviewed journal “Brain, Behavior and Immunity” and reveals how stress makes people more susceptible to illness. The findings also suggest a potential drug target for preventing damage to the immune systems of individuals suffering from long-term stress — such as caregivers to chronically ill family members, soldiers, air traffic controllers, astronauts and people who drive long daily commutes.

“We are testing therapeutic ways of enhancing telomerase levels to help the immune system ward off cortisol's effect”, said study author Rita Effros, a professor of pathology and laboratory medicine at the David Geffen School of Medicine at UCLA. “If we're successful, one day a pill may exist to strengthen the immune system's ability to weather chronic emotional stress."