Serum soluble lectin-like oxidized low-density lipoprotein receptor-1 correlates with oxidative stress markers in stable coronary artery disease

Abstract

Background: Although serum soluble lectin-like oxidized low-density lipoprotein receptor-1 (sLOX-1) is reported to be associated with acute coronary syndrome (ACS), its correlation with oxidative stress markers has not been elucidated. We therefore investigated the association of serum sLOX-1 with the severity of CAD, and serum biomarkers for oxidative stress and inflammation, as well as extracellular superoxide dismutase (EC-SOD), which is protective against oxidative stress in the vascular wall. Methods and results: Ninety-four patients with stable CAD were enrolled in this study. Serum sLOX-1, serum high-sensitivity C-reactive protein (hs-CRP), urinary 8-isoprostane, plasma BNP and serum lipid levels were measured. We also measured EC-SOD at baseline and post-heparin injection. Heparin-released EC-SOD (ΔEC-SOD) was calculated as the difference between these two values. No significant correlation was found between log (sLOX-1) and log (basal EC-SOD) ( p = 0.096), log (hs-CRP) ( p = 0.108), or log (BNP) ( p = 0.908) levels, log (sLOX-1) had a significant correlation with ΔEC-SOD ( r = − 0.325, p = 0.0014) levels and urinary 8-isoprostane levels ( r = 0.243, p = 0.020). In the multivariable analysis, ΔEC-SOD ( p = 0.0177) and 8-isoprostane ( p = 0.0318) were independent predictors for log (sLOX-1). Conclusion: Serum sLOX-1 levels were positively correlated with urinary 8-isoprostane levels and inversely correlated with EC-SOD levels. These results thus suggest that increased serum sLOX-1 levels may reflect enhanced oxidative stress in vascular walls.