Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1 Plays an Important Role in Vascular Inflammation in Current Smokers

Abstract

Smoking induces vascular inflammation and increases the risk of cardiovascular events. Lectinlike oxidized low-density lipoprotein receptor-1 (LOX-1) is a scavenger receptor that is induced by oxidative stress and is associated with atherosclerotic plaque formation and destabilization. LOX-1 interacts with C-reactive protein (CRP) and plays an important role in inflammatory diseases. We therefore hypothesized that LOX-1 may be involved in the onset of smoking-induced vascular inflammation. We measured the soluble LOX-1 (sLOX-1) levels in sera obtained from 207 current smokers. The serum sLOX-1 levels positively correlated with various smoking variables, such as the number of cigarettes smoked per day (r= 0.150, p<0.05), the expired air carbon monoxide (CO) concentrations (r= 0.198, p<0.005) and the Fagerstrom test for nicotine dependence scores (r= 0.190, p<0.01). The serum levels of sLOX-1 also correlated with those of a representative inflammatory marker, the serum high-sensitivity CRP level (hsCRP; r= 0.232, p<0.005). A multivariate regression analysis revealed the independent determinants of the serum sLOX-1 level to be the expired air CO concentration (β= 0.182, p<0.05) and the hsCRP level (β= 0.213, p<0.01). The serum sLOX-1 level was found to increase in close association with both the smoking-related variables and the inflammatory marker hsCRP. These findings suggest that LOX-1 may therefore play an important role in the onset of smoking-induced inflammation and atherosclerosis in humans.