LOX-1 may be involved in smoking-induced inflammation at vessel walls

LOX-1 may be involved in smoking-induced inflammation at vessel walls

Rieko Takanabe-Mori, Koh Ono, Hiromichi Wada, Tomohide Takaya, Hajime Yamakage, Noriko Satoh-Asahara, Akira Shimatsu, Yuko Takahashi, Masatoshi Fujita, Yoshiko Fujita, Tatsuya Sawamura, Koji Hasegawa.

Division of Translational Research, National Hospital Organization Kyoto Medical Center, Kyoto, Japan.

American College of Cardiology 61st Annual Scientific Session (Chicago, USA), 2012/03/25 (Poster).

Abstract

Background: Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a scavenger receptor, induced by oxidative stress, and suggested to be associated with atherosclerotic plaque destabilization. Soluble LOX-1 (sLOX-1) is known as a biomarker of acute coronary syndrome. It is reported that the LOX index, represented by multiplication of LOX-1 ligand containing apolipoprotein B (LAB) with sLOX-1, is associated with an increased risk of coronary artery disease and ischemic stroke. However, the role of sLOX-1 or LOX index as a cardiovascular risk marker in smokers is unknown. Therefore, we hypothesized that sLOX-1 and LOX index are related to smoking-related factors.

Method: We measured sLOX-1 and LAB levels in sera from 207 current smokers by ELISA.

Results: The sLOX-1 levels were positively correlated with smoking variables such as the number of cigarettes per day (r = 0.150, p < 0.05), expired air carbon monoxide (CO) concentrations (r = 0.198, p < 0.005), Fagerstrom test for nicotine dependence score (r = 0.190, p < 0.01), and serum high-sensitivity C-reactive protein levels (hsCRP; r = 0.232, p < 0.005). The multivariate regression analysis revealed that the independent determinants of serum sLOX-1 levels were expired air CO concentrations (β = 0.182, p < 0.05) and hsCRP levels (β = 0.213, p < 0.01). LOX index were positively correlated with the number of cigarettes per day (r = 0.188, p < 0.01), Brinkman index (r = 0.151, p < 0.05), Fagerstrom test for nicotine dependence score (r = 0.181, p < 0.05), BMI (r = 0.142, p < 0.05), LDL-C (r = 0.362, p < 0.0001) and serum hsCRP (r = 0.249, p < 0.005). The multivariate regression analysis revealed that the independent determinants of LOX index were expired air CO concentrations (β = 0.225, p < 0.01), hsCRP levels (β = 0.324, p < 0.0005) and LDL-C (β = 0.273, p < 0.005).

Conclusions: Both the serum LOX-1 level and the LOX index are increased in close association with the expired air CO concentration, one of smoking-related indicators, and the hsCRP level, a representative inflammatory marker. Thus, LOX-1 may be up-regulated by smoking-induced inflammation at vessel walls, being involved in the increased risk of cardiovascular diseases.