C-Reactive Protein

Chiayu Chen, M.D., F.A.C.C., Riverside Cardiology Associates Medical Group

• What is C-Reactive Protein?
• CRP and Atherosclerosis
• CRP and HMG-CoA Reductase Inhibitor Medication

What is C-Reactive Protein?

C-reactive protein (CRP) is an acute phase reactant. CRP is released by the body in response to acute injury, infection, or other inflammatory stimuli. Recent development of a high sensitivity assay for CRP (hs-CRP) has enabled investigation of this marker of systemic inflammation.

CRP and Atherosclerosis

Atheromatous plaques in diseased arteries typically contain inflammatory cells. Rupture of atheromatous plaque is thought to be the mechanism for acute myocardial infarction and acute coronary syndrome. The most common site of plaque rupture appears to be the shoulder region where inflammatory cells are most prominent. Thus the release of acute phase reactants as a response to inflammation have been proposed as a potential marker of an "unstable" atheromatous plaque and underlying atherosclerosis.

Studies have shown a positive association between CRP and coronary artery disease. In a survey of 388 British men aged 50-69, the prevalence of coronary artery disease increased 1.5 fold for each doubling of CRP level (Mendall MA, Patel P, Ballam L, et al. C-reactive protein and its relation to cardiovascular risk factor: A population based cross sectional study. BMJ. 1996;312:1061-1065.)

Multiple prospective studies have also demonstrated that baseline CRP is a good marker of future cardiovascular events (Riker P, Haughie P. Prospective studies of C-reactive protein as a risk factor for cardiovascular disease. J Investig Med. 1998;46:391-395.)

It has been suggested that CRP may be a good marker of cardiovascular risk in addition to lipid level.

CRP and HMG-CoA Reductase Inhibitor Medication

A recent study has shown that treatment with pravastatin, a HMG-CoA reductase inhibitor or statin medication, appears to result in significantly reduced levels of CRP (Ridker P, Nader R, et al. Long-term effects of pravastatin on plasma concentration of C-reactive protein. Circulation. 1999;100:230-235.)

The study was done on baseline and 5-year follow-up blood samples from the Cholesterol and Recurrent Events (CARE) trial. The CARE trial was a secondary prevention trial of cardiovascular disease in 4159 patients with a history of myocardial infarction who had total cholesterol <240 mg/dL and LDL cholesterol between 115 and 175 mg/dL.

In the recent study, Dr. Ridker and other CARE investigators demonstrated that CRP, a marker of inflammation, may be a modifiable risk factor. In addition, this study also gave us some insights into potential mechanisms of action for the medication pravastatin.

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