The Influence of Lipid Composition on the Binding of LDL to Chondroitin 6-Sulphate

The interaction between low-density lipoprotein (LDL) and glycosaminoglycans is a key factor in atherosclerosis. The present study examines the characteristics of LDL and its binding properties with the main glycosaminoglycan of the vascular wall, chondroitin 6- sulphate (C6S). The compositional characteristics that were studied for each LDL sample were phase transition temperature, phospholipid content, free cholesterol content, cholesteryl ester content, triglyceride content, and size. Correlations of these characteristics with LDL-C6S binding were analyzed using a turbidity assay. Our results showed that there is no correlation between LDL-C6S binding and phase transition temperature, triglyceride content, or size. Strong correlations were present for LDL-C6S binding and phospholipid content (P \u3c 0.0001, r2 = 0.4591), free cholesterol content (P \u3c 0.01, r2 = 0.2495), and cholesteryl ester content (P \u3c 0.005, r2 = 0.2952). When values for surface (phospholipids and free cholesterol) and core (cholesteryl esters and triglycerides) lipids were determined a positive correlation was also present with LDL-C6S binding (P \u3c 0.0005, r2 = 0.4172; P \u3c 0.0005, r2 = 0.4282; respectively). These results indicate that large, lipid-rich LDL particles have a higher capacity to bind C6S than smaller, lipid poor LDL. Possible implications for the atherogenicity of LDL are discussed