The novel role of C-reactive protein in cardiovascular disease: risk marker or pathogen

C-reactive protein (CRP) is a non-specific biomarker of inflammation. Recent research has shown that inflammation is an important step in the genesis of atherosclerosis, and is involved in the development of unstable plaques. Measurement of serum levels of CRP using a high sensitivity assay (hsCRP) can demonstrate subclinical inflammatory states, which may reflect vascular inflammation. Clinical studies have shown that elevated hsCRP levels in healthy populations predict vascular events such as myocardial infarction (MI) and stroke as well as the development of diabetes. In patients with acute coronary syndromes, higher hsCRP levels are associated with adverse outcomes and subsequent vascular events. There is data to suggest that aspirin, angiotensin converting enzyme (ACE) inhibitors and HMG Co-A reductase inhibitors (statins), which all reduce vascular event rates, also reduce serum levels of hsCRP and therefore hsCRP levels may potentially guide therapy. As well as having a critical role in risk prediction, recent evidence has emerged implicating CRP directly in atherogenesis. CRP has been found in human atherosclerotic plaque and CRP has been shown to cause endothelial cell dysfunction, oxidant stress and intimal hypertrophy in experimental models. We review the postulated roles of CRP in atherogenesis and prediction of vascular events, as well as discussing current recommendations for CRP testing in patients.