Protein linked to heart disease
Lowering levels of a protein in the blood could offer another way of reducing the risk of heart disease, a study suggests.
High levels of the C-reactive protein are linked to clogged arteries and damage to blood vessels in the heart.
Two US studies, funded by drug companies, found patients with lower CRP levels after treatment with statins had a lower risk of heart disease.
The research is published in the New England Journal of Medicine.
It has been suggested that high CRP levels could be an indicator of cardiovascular disease risk, even if someone does not have high cholesterol levels.
High cholesterol is the prime cause of clogged arteries.
But CRP, an inflammatory marker associated with the process of the build-up of fatty deposits within the artery walls, is also a contributory factor.
It has been suggested that statins can lower CRP levels as well as cutting cholesterol. The researchers set out to see if this was true.
In the first study, partly funded by Bristol-Myers Squib and Sankyo, scientists from the Brigham and Women's Hospital and Harvard Medical School in Boston monitored over 3,700 patients taking statins who had either had a heart attack or who had angina.
They were assigned to take either 80mg of atorvastatin or 40mg of pravastatin - two different kinds of statin - each day for two years.
Blood levels of LDL (low-density lipoprotein or 'bad' cholesterol involved in heart disease), were measured, along with levels of CRP.
Researchers also looked at whether patients experienced cardiovascular illness.
They found that, as expected, patients who had lower LDL cholesterol levels were less likely to have been ill.
But, in addition, patients who had lower CRP levels after statin treatment were also less likely to experience cardiovascular illness.
Those who had both low cholesterol and low CRP levels were the least likely to become ill.
Writing in the New England Journal, the researchers, led by Dr Paul Ridker, said: "Patients who have low CRP levels after statin therapy have better clinical outcomes than those with higher CRP levels, regardless of the resultant level of LDL cholesterol."
He suggested statins could be used to lower CRP levels as well as cholesterol.
In the second study, a team from the Cleveland Clinic Foundation monitored 500 patients with cardiovascular disease for 18 months.
Again, they were assigned to take a daily dose of either 80mg of atorvastatin or 40mg of pravastatin.
Ultrasound scans of the heart were carried out at the beginning and end of the study, funded by Pfizer, to see how their disease developed.
The researchers found lower CRP levels were linked to slower disease progression even when other factors, including reduced cholesterol levels, were taken into account.
The effect was greatest for patients on the higher statin dose.
The team, led by Dr Steven Nissen, said: "Our study raises the provocative question of whether the effects of statins on CRP, as well as LDL cholesterol, should be considered in decisions regarding therapy."
Belinda Linden, Head of Medical Information at the British Heart Foundation, said: "There is evidence to suggest that inflammation may be an important trigger for the development of coronary heart disease.
"This study supports previous research suggesting that treatment with statin drugs can influence C-reactive protein levels in the blood.
"Statins appear to have an anti-inflammatory effect as well as cholesterol lowering properties, so therefore it would follow that levels of C-reactive protein could possibly be lowered by statin treatment.
"However, the researchers point out themselves that further research is needed and that C-reactive protein should not be measured solely to moderate the statin dose."
Source: BBC News