Pharmacy Practice Faculty Publications

Title

Lipoprotein Lipase Greatly Enhances the Retention of Lipoprotein(a) to Endothelial Cell-Matrix

Document Type

Article

Publication Date

1-1999

Journal Title

Atherosclerosis

ISSN

0021-9150

Volume

142

Issue

1

First Page

89

Last Page

96

DOI

http://dx.doi.org/10.1016/s0021-9150(98)00195-6

PubMed ID

9920509

Abstract

The trapping of apolipoprotein (apo)B containing lipoproteins within the arterial subendothelial matrix (ECM) is an early event in atherosclerosis. When lipoprotein lipase, a constituent of the ECM, is prebound to ECM both LDL and oxidized LDL binding is greatly enhanced. In this study we compared the binding of lipoprotein(a) (Lp(a)), a lipoprotein correlated with atherosclerosis and restenosis, to ECM in the presence of varying concentrations of LPL. Without LPL, Lp(a) binding was low and non-saturable. In the presence of LPL, Lp(a) retention increased from 2.7×10−7 to 1.13×10−4 nmoles. Scatchard analysis demonstrated that the affinities of both Lp(a) and LDL to lipase were similar. In competition experiments, LDL, apoE, polymers of lysine and arginine were all capable of preventing the lipase specific [125I]Lp(a) retention. However, neither collagen nor fibronectin were capable of blocking or displacing [125I]Lp(a) from the lipase bound to ECM. In a separate set of experiments, when ECM was not saturated with lipase, both fibronectin and collagen (at 10-fold protein excess) prevented ≈40% of total [125I]Lp(a) retention to ECM. These data suggest, in the absence of lipase, apo(a) may regulate the binding of Lp(a) to ECM. Whereas, lipase enhanced the binding of Lp(a) to ECM, most probably through the apoB moiety of the Lp(a) particle.

Keywords

Matrix binding, lipoprotein lipase, lipoprotein(a), low density lipoproteina, apolipoprotein E