The gradual erosion of telomeres 鈥� the strands of DNA that cap our chromosomes and wear away with each cell division 鈥� may play a pivotal role in heart disease. People who go on to have heart attacks have much shorter telomeres than those who remain healthy, a major new study has shown.
Researchers from Leicester and Glasgow Universities in the UK took blood samples from 484 middle-aged men with moderately raised cholesterol, plus 1058 control subjects. They compared the telomere lengths in their white bloods cells at that time and then five years later.
Both patients and controls with the shortest telomeres five years on were twice as likely to have developed serious heart disease. Intriguingly, the study also found that drugs called statins, which are better known for their cholesterol-lowering properties, appeared to alleviate the effects of telomere damage 鈥� and may even have protected telomeres against degradation.
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However, the protective effect of statins was only seen in patients with comparatively short telomeres. 鈥淚n patients whose telomeres were wearing away at a normal rate, statin treatment didn鈥檛 make any difference,鈥� says Leicester University cardiologist Nilesh Samani, who led the research. 鈥淭his suggests that statins were protecting against the worst cases of telomere degradation. Without statins they might have been even shorter.鈥�
These unexpected discoveries provide important new insights into the causes of arterial disease 鈥� the western world鈥檚 biggest killer.
Statin suspicion
For years, doctors and scientists have suspected that another property of statins, unrelated to their cholesterol-lowering ability, explained how they protected patients from heart disease and stroke so effectively. Samani believes his team鈥檚 findings may help explain just why statins are so effective.
He notes that exactly how statins might limit the damage caused by telomere shortening 鈥� or even directly protect telomeres 鈥� was 鈥渟peculation at this stage鈥�. But his group has already begun laboratory studies to test how the drugs interact with telomeres.
鈥淎nd, for me, just as interesting are the implications in terms of biological ageing.鈥� Samani adds. 鈥淭here is the distinct possibility that telomere length can provide us with a marker to identify people whose hearts are ageing more rapidly.鈥�
So how do shortened telomeres increase your risk of heart disease? According to cardiologist Stefanie Dimmler at the University of Frankfurt in Germany, degraded telomeres might cause heart disease by impeding the ability of cells from the bone marrow to repair damaged parts of the arterial walls.
鈥淭his could explain how shortened telomeres increase a person鈥檚 risk of heart disease,鈥� agrees Samani.
Journal reference: The Lancet (vol 369, pg 107)
