Bad Boy in the Blood: CRP
Heart Disease, Sudden Death Tied to Blood Protein
Jan. 15, 2003 -- It's known as high-sensitivity C-reactive protein or hsCRP. Now it's being called a killer.
The body makes CRP to help it fight infection. But ongoing high levels of the blood protein mean high risk of heart disease, stroke, and sudden cardiac death. It also seems to be an early sign of the development of type 2 diabetes.
Now it looks like CRP is more than alarm. It appears to play a central role in the formation of blood clots that cause heart attacks and stroke. Ishwarlal Jialal, MD, PhD, director of the laboratory for atherosclerosis and metabolic Research at the University of California, Davis, and colleagues report the new findings in the Jan. 25 issue of the journal Circulation.
"CRP does more than sit in your blood vessels. It is an active contributor to heart disease. It is not innocent bystander," Jialal tells WebMD. "CRP doesn't just mark risk. It contributes to plaque formation in the blood-vessel wall. It promotes cholesterol uptake."
CRP isn't always a bad guy. The liver makes it to help the body heal wounds and fight infections. But when CRP hangs around too long, it becomes most unwelcome.
"The problem we are talking about is a lifetime of low-grade, nagging inflammation," Jialal says. "It might be you have a dental infection over many years, or something like oxidative stress. ... The most dazzling observation has been that in postmenopausal women, even those with low cholesterol levels, CRP identifies a three-fold increased risk for coronary artery disease."
In their lab, Jialal's team grew cultures of the cells that line the inside of blood vessels. When they added CRP to these cells, they saw dramatic effects. The cells began to secrete a substance called PAI-1. Increased PAI-1 secretion predicts formation of blood clots and heart disease. It also predicts diabetes and the pre-diabetes condition known as metabolic disorder.
"Metabolic syndrome is the plague of our time," Jialal says. "This is an area of intense inquiry in my research lab."
There's a lot a person can do about CRP, Jialal and colleague Sridevi Devaraj, PhD, note in the Jan. 15 issue of The American Journal of Cardiology. You can lower your CRP levels by doing the same things you would do to lower your cholesterol levels: lose weight, eat fewer calories and a very low fat diet, take the cholesterol-lowering drugs known as statins, and the natural form of vitamin E.
There's a simple blood test for CRP. Many doctors already have begun to measure some patients' CRP levels, says cardiologist Arshed Quyyumi, MD, professor of medicine at Atlanta's Emory University.
"This may well become something we will add to our standard list of things that we measure," Quyyumi (pronounced cue-YOU-me) tells WebMD. "It is not there yet because the test and what to make of it needs to be worked out in terms of what it means for an individual. We cardiologists sometimes measure CRP because we see people who already have heart disease. If you are seeing someone young and relatively healthy, and they have low cholesterol and normal blood pressure, that might be the reason to measure CRP. A high CRP level might frighten such people into dieting and taking care of themselves."
The CDC and the American Heart Association are already working out guidelines for measuring CRP. Jialal says he will be "shocked" if CRP tests aren't soon recommended for people at risk of heart disease but with normal cholesterol levels. Related Link:
Simple Blood Test Predicts Heart Disease, Nov. 13, 2002