MONDAY, Aug. 26, 2002 (HealthDayNews) -- If you're heart-conscious and are not yet familiar with c-reactive protein, you should get to know about it, because a new study solidifies its emerging role as a risk factor ranking with cholesterol.
The study, done by researchers at the University of California at Davis, outlines the molecular pathway by which c-reactive protein (CRP, as it's often abbreviated) causes arterial damage that can end in a heart attack or stroke.
The damage is done through inflammation of the endothelium, the delicate outer layer of arterial cells. Those damaged cells are vulnerable to the formation of plaque, the fatty deposit that can rupture and block the artery.
"What we have teased out is that c-reactive protein interferes with a very critical enzyme that produces nitric oxide," says Dr. Ishwarlal Jialal, director of the UC Davis Laboratory for Atherosclerosis and Metabolic Research and lead author of a paper reporting the finding in the journal Circulation: Journal of the American Heart Association. Nitric oxide plays a key role in keeping endothelial cells healthy, he says.
"More important, c-reactive protein causes more white blood cells to adhere to the endothelium, which is the first step in plaque formation," Jialal says. "When you piece all of the evidence together, including the results of previous clinical studies, you can show that if you have a high CRP level, irrespective of cholesterol, you are vulnerable to a heart attack."
There are several ways to lower CRP levels, he says. One is to lose weight, if you are obese. Another is to take aspirin. And statins, the widely used cholesterol-lowering drugs, have also been shown to reduce CRP levels.
CRP levels are increased by most of the commonly accepted cardiovascular risk factors, such as smoking, obesity, and high blood sugar levels, Jialal says. "I believe there is a place in therapy for CRP reduction."
Treatment can be started if someone is found to have elevated CRP levels in two consecutive tests, two weeks apart -- if they don't have an infection, Jialal says; any infection increases CRP levels. The doctor can then choose the best treatment for a given patient, he says. Weight loss is often effective in obese women but does not work as well in men, he adds.
Dr. Richard A. Stein, professor of clinical medicine at Weill Cornell Medical Center in New York and a spokesman for the American Heart Association, says he now tests many patients for CRP because of a long sequence of studies linking the molecule to inflammation and artery damage.
"Five years ago, we began to appreciate that CRP is a marker of inflammation," Stein says. "We've been fascinated over the past decade by the relationship of inflammation to atherosclerosis. If you open a plaque, you see a lot of what you see in infection, such as white blood cells, lacking the bacteria. About two years ago, studies began to show that CRP might not just be a marker of arterial disease but might atherogenic [plaque-causing].
"I used to do just a cholesterol test on these patients. Now in my practice I also do c- reactive protein and homocysteine, another risk factor. Most cardiologists now are doing that, and hopefully primary care physicians will, too," he adds.
Statin therapy is "the most powerful way" to treat high CRP, Stein says, adding that "most of these patients are probably on a statin already."
What To Do
You can learn about the role of inflammation in cardiovascular disease from the American Heart Association, which also has a page on risk factors you can change.
