DNA strands might predict heart disease

Short telomeres, also tied to aging, increase likelihood of illness, study says

updated 6:00 p.m. ET Jan. 12, 2007

LONDON - British scientists have discovered a potential new way to identify people who have a higher risk of developing heart disease.

Telomeres, tiny strands of DNA at the ends of chromosomes that seem to contain secrets about aging, may also hold clues about who is more likely to suffer from coronary heart disease.

The researchers, who measured telomere length in leukocytes, or white blood cells, in 1,500 men 45-64 years old, found short telomeres indicate a higher likelihood of developing heart disease.

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“We have shown that leukocyte telomere length is associated with future coronary heart disease events in middle-aged, high-risk men,” professor Nilesh Samani, of the University of Leicester in England, said in a report in The Lancet medical journal Friday.

Telomeres protect the ends of chromosomes from fraying. They shorten each time a cell divides and the loss is associated with aging. As telomeres get smaller, the chromosomes can become unstable and at greater risk of mutation.

Earlier research had shown that people with heart disease have shorter telomeres, but it was not clear until now if telomere length could be a predictive marker for the illness.

“They have shown that it is a predictor. It doesn’t say it is functionally linked to heart disease but it is certainly associated with it,” said professor Jeremy Pearson of the British Heart Foundation.

He said the findings are also important in understanding the disease process and in finding ways to prevent heart attacks.

The researchers, who compared the length of telomeres of 484 men who went on to develop heart disease and 1,058 healthy men, found shorter telomere length was linked to disease risk.

Heart disease is a leading killer in industrialized countries. Smoking, being overweight or obese, lack of exercise, high blood pressure, diabetes and raised cholesterol levels increase the odds of developing the illness.

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In addition to pinpointing which men might develop heart disease, Samani and his team said telomere length could be used to help identify men who would benefit from taking cholesterol-lowering drugs known as statins to reduce their risk of heart disease.

They showed statins lowered the odds of developing heart disease in patients with short telomeres. But if patients with short telomeres were given a placebo, or dummy pill, their odds of illness were almost double compared to people with long telomeres.

Pfizer’s Lipitor, Merck’s Zocor and AstraZeneca’s Crestor are among the leading statins.