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Life Expectancy Can Be Predicted By Your DNA Length

Telomeres, repeated nucleotide sequences at the tips of chromosomes, appear white in this photo.
Telomeres, repeated nucleotide sequences at the tips of chromosomes, appear white in this photo. They were shortened in cardiac patients who have lower life expectancy. NIH/HESED PADILLA-NASH AND THO

Researchers analyzed the length of telomeres, the tips of each of the 46 chromosomes, and found that their size accurately predicted the length cardiac patients would live.

Telomeres are caps on the ends of chromosomes whose job it is to protect the DNA from degradation. The usually get shorter with age and short telomeres are known to be associated with diseases such as cancer and heart disease. Cells that proliferate constantly, like stem cells, do not lose their telomeres and appear to be ageless.

In the current study scientists analyzed the telomere length of cells from peripheral blood taken from 3,500 patients with heart disease and stroke. The longer the ends of the chromosomes, the longer people lived.

Previous studies have shown that telomeres can accurately predict the age of people, but this study expands the prediction to how long heart disease patients might live.

"Chromosomes by their nature get shorter as we get older," said John Carlquist, PhD, director of the Intermountain Heart Institute Genetics Lab. "Once they become too short, they no longer function properly, signaling the end of life for the cell. And when cells reach this stage, the patient's risk for age-associated diseases increases dramatically."

Dr. Calquest continued.

"Our research shows that if we statistically adjust for age, patients with longer telomeres live longer, suggesting that telomere length is more than just a measure of age, but may also indicate the probability for survival. Longer telomere length directly correlate with the likelihood for a longer life -- even for patients with heart disease," 

"I believe telomere length could be used in the future as a way to measure the effectiveness of heart care treatment," said Dr. Carlquist. "We can already test cholesterol and blood pressure of a patient to see how treatment is working, but this could give us a deeper view into how the treatment is affecting the body and whether or not the treatment is working."

Researchers in other fields are studying the role that telomeres play in aging and cancer. Cancer cells have the ability to rebuild their telomeres even though they are dividing rapidly, hence they remain viable and do not get exhausted from proliferating. Scientists hope to harness information about this process to not only treat cancer, but to possibly alter the aging process. 

Elizabeth BlackburnCarol Greider, and Jack Szostak were awarded the 2009 Nobel Prize in Physiology or Medicine for the discovery of how chromosomes are protected by telomeres and the enzyme telomerase. 

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