Monocyte cyclooxygenase-2 overactivity:: a new marker of subclinical atherosclerosis in asymptomatic subjects with cardiovascular risk factors?

Aims Cyclooxygenase-2 (COX-2)-mediated prostaglandin production by activated macrophages is associated with inflammation and atherosclerosis. We investigated the relationship between COX-2-mediated prostaglandin-E-2 (PGE(2)) release, cardiovascular risk factors, and carotid atherosclerosis in apparently healthy subjects. Methods and results PGE2 release by lipopolysaccharide-stimulated blood monocytes was measured by ELISA in 291 subjects (76.5 % men, mean age 58) who underwent global vascular risk assessment and carotid ultrasonography. COX-2 expression (real-time RT-PCR) was analysed in a subgroup of 100 subjects (76 % men, mean age 59). Inducible PGE2 production was associated with smoking and diabetes (P < 0.05), but not with arterial hypertension, dyslipidaemia, or obesity. Subjects in the highest tertile of PGE2 (> 8.1 ng/mL) had significantly higher mean carotid intimamedia thickness (IMT) than those in the Lowest tertile (P < 0.01). No significant differences among tertiles were observed in the levels of inflammatory markers (C-reactive protein, fibrinogen, and von Willebrand factor). The association between PGE2 and carotid IMT remained statistically significant (P = 0.012) after adjustment for a number of cardiovascular and inflammatory risk factors. A correlation between COX-2 expression and PGE2 production was observed (P < 0.005). Conclusions COX-2-mediated PGE2 overproduction by stimulated monocytes might provide a new marker of subclinical atherosclerosis in asymptomatic subjects exposed to cardiovascular risk factors.