It is well recognized that oxidative modification of low-density lipoprotein (LDL) accelerates atherogenesis of the arterial vascular wall. In this study, we examined the relationship between various methods of measuring the extent of oxidation, namely lipid peroxidation products, surface charge, and spectrophotometric patterns. LDL was isolated from fresh human normal plasma by centrifugation and was oxidized by incubating with copper ions. Apolipoprotein B was isolated from the LDL solution. We also prepared artificial lipid particles composed of cholesterol linolenate, triolein, and phosphatidylcholine. Our results suggest that lipid peroxidation begins drastically in 30–60 min, while the abolition of the positive charge on apoliproproteins is accelerated after 60 min. We found a characteristic change in the spectrophotometric pattern during the process and conclude that the spectrophotometric absorption ratio at 232 and 203 nm is a useful measure of in vitro oxidation of LDL.
Ylä-HerttualaSPalinskiWRosenfeldMEParthasarathySCarewTEButlerS. Evidence for the presence of oxidatively modified low density lipoprotein in atherosclerotic lesions of rabbit and man. J Clin Invest1989; 84: 1086–95.
ManginELJrKugiyamaKNguyJHKernsSAHenryPD. Effects of lysolipids and oxidatively modified low density lipoprotein on endothelium-dependent relaxation of rabbit aorta. Circ Res1993; 72: 161–6.
4.
PettersenKSBobergKMStabursvikAPrydzH. Toxicity of oxygenated cholesterol derivatives toward cultured human umbilical vein endothelial cells. Arterioscler Thromb1991; 11: 423–8.
5.
JialalIFreemanDAGrundySM. Varying susceptibility of different low density lipoproteins to oxidative modification. Arterioscler Thromb1991; 11: 482–8.
6.
SteinbergDParthasarathySCarewTEKhooJCWitztumJL. Beyond cholesterol, modifications of low-density lipoprotein that increase its atherogenicity. N Engl J Med1989; 320: 915–24.
7.
KalantNMcCormickSParniakMA. Effects of copper and histidine on oxidative modification of low density lipoprotein and its subsequent binding to collagen. Arterioscler Thromb1991; 11: 1322–9.
8.
HeineckeJWSuitsAGAviramMChaitA. Phagocytosis of lipase-aggregated low density lipoprotein promotes macrophage foam cell formation, sequential morphological and biochemical events. Arterioscler Thromb1991; 11: 1643–51.
9.
NicholsonACFriedaNSPearceASilversteinRL. Oxidized LDL binds to CD36 on human monocyte-derived macrophages and transfected cell lines, evidence implicating the lipid moiety of the lipoprotein as the binding site. Arterioscler Thromb Vasc Biol1995; 15: 269–75.
10.
QuinnMTParthasarathySSteinbergD. Lysophosphatidylcholine; a chemotactic factor for human monocytes and its potential role in atherogenesis. Proc Natl Acad Sci USA1988; 85: 2805–9.
11.
OhgushiMKugiyamaKFukunagaKMurookaTSugiyamaWMiyamotoE. Protein kinase C inhibitors prevent impairment of endothelium-dependent relaxation by oxidatively modified LDL. Arterioscler Thromb1993; 13: 1525–32.
12.
YagiK. A simple fluorometric assay for lipoperoxide in blood plasma. Biochem Med1976; 15: 212–6.
13.
MaggiEChiesaRMelissanoGCastellanoRAstoreDArossiA. LDL oxidation in patients with severe carotid atherosclerosis, a study of in vitro and in vivo oxidation markers. Arterioscler Thromb1994; 14: 1892–9.
14.
EsterbauerHStrieglGPuhlHTothenederM. Continuous monitoring of in vitro oxidation of human low density lipoprotein. Free Rad Res Commun1989; 6: 67–75.
15.
PetersonGL. A simplification of the protein assay method of Lowry et al. which is more generally applicable. Anal Biochem1977; 83: 346–56.
16.
OlofssonSOBoströmKSvanbergUBondjersG. Isolation and partial characterization of a polypeptide belonging to apolipoprotein B from low-density lipoproteins of human plasma. Biochemistry1980; 19: 1059–64.
17.
TajimaSYokoyamaSYamamotoA. Effect of lipid particle size on association of apolipoproteins with lipid. J Biol Chem1983; 258: 10073–82.
18.
YagiKKikuchiKSaitoYMiikeAKayaharaNTatanoT. Use of a new methylene blue derivative for determination of lipid peroxides in foods. Biochem Int1986; 12: 267–71.
19.
JurgensGHoffHFChisolmGM3rdEsterbauerH. Modification of human serum low density lipoprotein by oxidation-characterization and pathophysiological implications. Chem Phys Lipids1987; 45: 315–36.
20.
SteinbrecherUP. Oxidation of human low density lipoprotein results in derivatization of lysine residues of apolipoprotein B by lipid peroxide decomposition products. J Biol Chem1987; 262: 3603–8.
21.
BallaGJacobHSEatonJWBelcherJDVercellottiGM. Hemin: A possible physiological mediator of low density lipoprotein oxidation and endothelial injury. Arterioscler Thromb1991; 11: 1700–11.
22.
ReavenPDParthasarathySBeltzWFWitztumJL. Effect of probucol dosage on plasma lipid and lipoprotein levels and on protection of low density lipoprotein against in vitro oxidation in humans. Arterioscler Thromb1992; 12: 318–24.
23.
OkadaMSugitaOMiidaTMatsutoTInanoK. Effects of modified low density lipoprotein and hypoxia on the expression of endothelial leukocyte adhesion molecule-1. Presse Med1995; 24: 483–8.
24.
ReavenPDFergusonENavabMPowellFL. Susceptibility of human LDL to oxidative modification. Effects of variations in β-carotene concentration and oxygen tension. Arterioscler Thromb1994; 14: 1162–9.
25.
Hurt-CamejoECamejoGRosengrenBLópezFAhlströmCFagerG. Effect of arterial proteoglycans and glycosaminoglycans on low density lipoprotein oxidation and its uptake by human macrophages and arterial smooth muscle cells. Arterioscler Thromb1992; 12: 569–83.
26.
HoffHFO'NeilJ. Lesion-derived low density lipoprotein and oxidized low density lipoprotein share a liability for aggregation, leading to enhanced macrophage degradation. Arterioscler Thromb1991; 11: 1209–22.
27.
HermannMGmeinerB. Altered susceptibility to in vitro oxidation of LDL in LDL complexes and LDL aggregates. Arterioscler Thromb1992; 12: 1503–6.
