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Protein
Identified as Heart Risk Factor
(HealthScoutNews)
-- Researchers have identified a new coronary risk factor: high
blood levels of an inflammation-related molecule called C-reactive
protein (CRP). And they say that risk can be reduced by taking
one of the statins, the drugs that cut heart risk by lowering
cholesterol levels.
The June
28 New England Journal of Medicine reports that statin
therapy reduced the risk of heart attacks for people with low
cholesterol levels and high CRP levels in a five-year study of
more than 5,700 participants.
The drug
in the study was lovastatin, marketed as Mevacor, but "all the
other statins also lower blood levels of CRP," says Dr. Kenny
Jailal, professor of pathology at the University of Texas Southwestern
Medical Center in Dallas.
CRP is part
of the body's response to infection. The molecule binds to the
surface of invading microbes, marking them for attack by the immune
system. It also neutralizes oxidants called proteases and other
potentially harmful molecules released from the site of an inflammation.
There are
at least two theories explaining CRP's protective effect. One
says it reduces inflammation of the endothelium, the sensitive
lining of the arteries. Another says it limits the formation of
blood clots that could block arteries.
Statins also
are believed to have an anti-inflammatory effect on the endothelium,
which may partly explain how they help in other diseases. One
study last year reported a lowered risk of Alzheimer's disease
among older people who took statins to reduce cholesterol levels.
Another study found a lowered risk of stroke and diabetes.
Dr. Paul
Ridker, a cardiologist at Brigham and Women's Hospital in Boston
and leader of new study, says in a statement that the findings
"confirm the importance of inflammation in heart disease. …
Now we are closer to a biological understanding not only about
who is at high risk, but also about who is most likely to benefit
from aggressive therapy."
Jailal says
a blood test for CRP levels is available now, but it must be used
with care because "triggers for elevated CRP can come from anywhere
-- a sprained ankle, tonsillitis, another injury."
"We would
need at least two estimates, a week apart, to tell you what risk
you have. After all, we don't treat people on the basis of one
elevated cholesterol reading," Jailal says.
A blood test
for CRP is available at "most good academic centers," he says,
but it might not be suitable for coronary screening. The test
is designed to detect the very large increases of CRP in severe
inflammations, when blood levels can go up 500-fold. A more sensitive
test is needed to detect the much less dramatic increase that
could signal coronary risk, Jailal says.
And Ridker
says further study is needed to apply the new findings. "If we
are going to change clinical practice, we will now need to undertake
a large-scale randomized trial directly evaluating statin therapy
among those with low cholesterol levels and high levels of CRP."
Jailal says
nonprescription ways to lower CRP levels includes a daily 300-milligram
dose of aspirin or 800 international units of vitamin E daily.
What To
Do
Until more
definitive information is available about CRP and its effect on
heart disease, pay attention to the well-established risk factors,
including high blood cholesterol, high blood pressure, inactivity
and smoking.
For detailed
information about risk factors and what to do about them, visit
the
American Heart Association or the
Centers for Disease Control and Prevention.
Reference
Source 101
For more information on how to prevent other diseases, use
PreventDisease.com's "Quick
Prevention Resources".
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