Isolation, characterization, and functional assessment of oxidatively modified subfractions of circulating low-density lipoproteins

Chao Yuh Yang, Joe L. Raya, Hsin Hung Chen, Chu Huang Chen, Yasunori Abe, Henry J. Pownall, Addison A. Taylor, Charles V. Smith

Research output: Contribution to journalArticle

85 Scopus citations

Abstract

Objective - Current evidence suggests that oxidatively modified human plasma low-density lipoproteins (ox-LDLs) are proatherogenic and cytotoxic to endothelial and vascular smooth muscle cells. The present study describes a method using ion-exchange chromatography that is capable of large-scale subfractionation of LDL for adequate analyses of composition or bioactivities. Methods and Results - LDLs from normolipidemic (N-LDL) and homozygous familial hypercholesterolemic (FH-LDL) subjects were separated into 5 subfractions (L1 through L5) by high-capacity ion-exchange chromatography. The most strongly retained fraction from FH subjects, FH-L5, suppressed DNA synthesis in cultured bovine aortic endothelial cells and stimulated mononuclear cell adhesion to cultured endothelial cells under flow conditions in vitro. L5, which represented 1.1±0.2% and 3.7±1.7% of the LDL from N-LDL and FH-LDL, respectively, was more triglyceride-rich (17% versus 5%) and cholesteryl ester-poor (23% versus 33%) than were L1 through L4. Electrophoretic mobilities on agarose gels increased from L1 to L5. According to SDS-PAGE, apolipoprotein B-100 in N-LDL fractions L1 through L5 appeared as a single ≈500-kDa band. In contrast, the fractions isolated from FH-LDL showed substantial fragmentation of the apolipoprotein B-100, including bands between 200 and 116 kDa. Competitive ELISA analyses using a malondialdehyde-specific monoclonal antibody against Cu2+ ox-LDL suggest that FH-L5 is malondialdehyde-modified. Conclusions - Relative to N-LDL, FH-LDL contains higher concentrations of a fraction, L5, that exhibits distinctive physicochemical properties and biological activities that may contribute to initiation and progression of atherogenesis in vivo.

Original languageEnglish (US)
Pages (from-to)1083-1090
Number of pages8
JournalArteriosclerosis, Thrombosis, and Vascular Biology
Volume23
Issue number6
DOIs
StatePublished - Jun 1 2003

Keywords

  • Adhesion molecule induction
  • Atherosclerosis
  • DNA synthesis
  • Hypercholesterolemia
  • Oxidized LDL

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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