Levels of Small Dense LDL, Lipids and Lipoproteins in Patients with Coronary Artery Stenosis and Healthy Individuals

Low density lipoprotein (LDL) particles are heterogenous with respect to their size,density and lipid composition. Among LDL particles, the smaller and denser LDLs (small dense (sd)LDL) are believed to be atherogenic since these particles are taken up more easily by arterial wall.They are readily oxidized and have reduced affinity for LDL receptor and increased affinity for arterial proteoglicans. Therefore, they are strongly associated with development of coronary artery disease(CAD).The aim of this study was to compare sdLDL levels in CAD patients and healthy individuals. Patients and In this comparative cross-sectional and case-control study, the sdLDL levels were determined in 86 patients with coronary stenosis,35 patients without coronary stenosis confirmed by angiography, and 30 healthy individuals. SdLDL was measured by a direct homogenous LDL-C assay in the supernatant of serum that remained after heparin-magnesium precipitation. The results of ANOVA test showed that the sdLDL levels were higher in patients with coronary stenosis than patients without coronary stenosis and healthy individuals(21.54±7.1 mg/dl,16.88±4.4 mg/dl and 15.45±5 mg/dl respectively, p=0.001). In addition, linear regression analysis and Pearson correlation coefficient revealed that sdLDL levels were positively correlated with serum triglyceride (r=0.494),total cholesterol(r=0.354) and LDL-C(r=0.749) and were inversely correlated with HDL-C(r=-0.586) (p<0.01). The results suggest that patients with increased levels of sdLDL are at high risk for coronary artery stenosis.