Widespread vascular production of C-reactive protein (CRP) and a relationship between serum CRP, plaque CRP and intimal hypertrophy.

OBJECTIVES

Evidence of local vascular production and a relationship between serum hsCRP levels and tissue expression of CRP in subjects with vascular disease would support a direct role for CRP in atherosclerosis.

METHODS AND RESULTS

Vascular tissue from subjects undergoing coronary artery bypass grafting surgery (CABGS) (n=28) and carotid endarterectomy (CEA) (n=25) were studied. Histological samples were assessed for intima-media ratio (IMR) and CRP by immunohistochemistry. CRP mRNA was quantified by real-time polymerase chain reaction. CRP mRNA was seen in all plaques, non-atherosclerotic artery and atrium but no difference in mRNA expression was seen between plaque and non-atherosclerotic tissue. Serum hsCRP correlated with IMR (r=0.64, p=0.001) in non-atherosclerotic arteries and with plaque CRP staining (r=0.57, p=0.009) independent of age, BMI, lipids, diabetes and blood pressure. In a separate patient series, serum hsCRP was measured in aortic and coronary sinus blood from subjects undergoing CABGS or angiography (n=54). There was a coronary circulation hsCRP gradient ([mean+/-S.E.M.] aortic CRP 4.3mg/l+/-0.8 versus coronary sinus 5.8+/-1.2mg/l, p<0.05).

CONCLUSIONS

Widespread vascular CRP mRNA expression, a correlation between serum hsCRP, intimal hypertrophy and plaque CRP, and a coronary hsCRP gradient suggest vascular secretion may contribute to serum CRP levels.