Stress and aging
In the privacy of sensitive genetic mechanisms governing cell division and multiplication, scientists first found evidence that the anticipated stress aging.

The finding of the neuroendocrinology laboratory at the University of California shows that an accumulation of stressful situations can add many more years to the DNA of a person than his actual chronological age.

The scientists found that blood cells from women who had spent most of their lives caring for a disabled child were, genetically speaking, a decade older than the same cells of those mothers who had less time in the same difficult task.

The study, which appears in Proceedings of the National Academy of Sciences of the USA, also suggests that the perception of being stressed can add years genetic biological age of a person.

Though doctors have linked chronic psychological stress to weakened immune function and increased risk of infection, still trying to understand how that tension damages and weakens the body’s tissues.

New research suggests one way that this deterioration could occur and, even more promising, at the same time opens the possibility that the process can be reversed.

Effects of aging: tissue damage.
“This is a significant finding,” said Dr. Bruce McEwen, director of the neuroendocrinology laboratory at Rockefeller University in the city, adding that the research provided some of the clearest evidence ever found so far about “damage paid by tissues after a stressful life.

“We know that as we age,” continued Dr. McEwen, “we have more tendency to gain weight, develop heart disease and diabetes, but this is a novelty.”

In the experiment, the doctors Elissa Epel and Elizabeth Blackburn of the University of California, San Francisco led a team of researchers who analyzed blood samples of 58 young mothers and middle-aged, 39 of them caring for a child with chronic diseases such as autism or cerebral palsy. Using genetic techniques, examined the DNA of white blood cells, which are essential for the body’s response to infection.

The scientists focused on a piece of DNA called the telomere, at the end of the chromosomes of the cell.

As the head of a split matchstick, the telomere shrinks each time a cell divides and duplicates itself.

Cells may reproduce themselves many times in life to repair and strengthen their host organs, to grow or to fight disease.

A chemical called telomerase helps restore a portion of the telomere with each division.

But after 10 to 50 divisions, approximately, the number varies by tissue type and condition of the person: biologists still do not understand how the system works well, but the telomere gets so short that the cell can not reproduce more .

People born with a genetic disease called dyskeratosis congenita, which causes accelerated shortening of telomeres, die young, usually by middle age, most often from complications due to a weak immune system.

In short, it is believed that the change in telomere length, over time, is a measure of cell age, its vitality.

When the researchers compared the DNA of mothers caring for disabled children, found a striking trend: after considering the effects of age, they calculated that the longer women had been caring for her child, the shorter was the length of the telomere and lower their telomerase activity.

Some of the more experienced mothers were years older than their chronological age, as measured by their white blood cells.

“When people under stress look haggard, it’s like they age before our eyes, and here’s something going at the molecular level, that’s what reflects that impression, said Dr. Blackburn, a professor of biochemistry and biophysics.

The researchers also gave the women a questionnaire asking them to establish a score in a three-point scale to indicate the degree of exhaustion they felt in their daily lives and how often were unable to control the important things. Women who were under heavy stress also had significantly shortened telomeres compared with those from whom they felt more relaxed, or were raising a disabled child.

“Some of the women who had a real stress also had a low perception of it and the next step is to try to understand what causes this type of resilience,” said Dr. Epel.

Epel said they planned to study the effect of meditation and meditation training and yoga, both as perceived stress in telomere length. One type of treatment, cognitive therapy, in which people learn to temper their responses to stress, could also help, psychologists say.

Genes and education
However, the personality and upbringing probably also have to make a difference. In 2003 a group of researchers began studying 850 people in New Zealand from birth to age 26 and reported that variations in a single gene helped predict which children will later be susceptible to depression to stressful events, such as divorce and unemployment.

Researchers at the National Institutes of Health in the U.S. in monkeys showed that a loving and attentive rearing of offspring could protect the young of this genetic variation by promoting resilience in genetically vulnerable individuals. An education and excessive cold, psychiatrists say, can have the opposite effect.

“All these factors are intertwined in the way a person handles stress,” said Dr. Ronald Glaser, director of the Institute for Behavioral Medicine Research at Ohio University, who with his wife, Dr. Janice Kiecolt-Glaser, has documented the effect of stress on immune function. Now we have evidence from a wide range of fields, from studies of wound healing, inflammation, vaccines, and recently, the age of the cells, what really explains the Stress can cause damage. ”

Experts caution that the telomere study needs to be repeated and that no one has shown convincingly that psychological stress significantly shortens people’s lives.

Other effects of stress
Moreover, it is far from clear exactly how worrying about the problems of learning a child, for example, can cause parental telomeres shorten prematurely. Although researchers know that emotional stress of this type causes the release of stress hormones like cortisol, which over time can damage cells, no one knows how these hormones or other stress-related toxins affect telomeres.

“For now, that’s the black box,” said Dr. Blackburn. “And that’s what we’re going to study next.”