Comparative reactivity of remnant-like lipoprotein particles (RLP) and low-density lipoprotein (LDL) to LDL receptor and VLDL receptor: Effect of a high-dose statin on VLDL receptor expression

Background: Comparison of the reactivity of remnant-like lipoprotein particles (RLP) and LDL particles to LDL receptor and VIOL receptor has not been investigated. Methods: LDL receptor- or VLDL receptor-transfected IdlA-7, HepG2 and L6 cells were used. Human LDL and rabbit beta-VLDL were isolated by ultracentrifugation. Human RLP was isolated using an immunoaffinity mixed gel. The effect of statin on lipoprotein receptors was examined. Results: Both LDL receptor and VLDL receptor recognized RLP. In LDL receptor transfectants, RLP, beta-VLDL and LDL all bound to LDL receptor. Cold RLP competed efficiently with Dil-beta-VLDL; however, cold LDL competed weakly. In VLDL receptor transfectants, RLP and beta-VLDL bound to VLDL receptor, but not LDL RLP bound to VLDL receptor with higher affinity than beta-VLDL because of higher apolipoprotein E in RLP. LDL receptor expression was induced in HepG2 by the low concentration of statin while VLDL receptor expression was induced in L6 myoblasts at higher concentration. Conclusions: RLP are bound to hepatic LDL receptor more efficiently than LDL, which may explain the mechanism by which statins prevent cardiovascular risk by primarily reducing plasma RIP rather than by reducing LDL Additionally, a high-dose of statins also may reduce plasma RLP through muscular VLDL receptor. (C) 2011 Elsevier B.V. All rights reserved.