title: Analysis of lipoprotein diene formation in human serum exposed to copper.
abstract: The susceptibility of low density lipoprotein (LDL) to oxidative modification can be determined by analyzing the lag phase for initiation of diene formation in isolated LDL exposed to Cu2+. However, the applicability of this assay for clinical studies is limited by the requirement of a preparative ultracentrifugation of LDL and that the influence of water soluble antioxidants and other lipoproteins is not accounted for. The present paper describes a modification of this assay allowing determination of lag phase for lipoprotein diene formation in serum. The formation of dienes in serum exposed to Cu2+ begins following the consumption of serum alpha-tocopherol, correlates to the formation of thiobarbituric acid reactive substances (r = 0.987, n = 8), is inhibited by the addition of ascorbic acid and is absent in lipoprotein-deficient serum. It is also accompanied by an increased mobility of serum lipoproteins on agarose gel electrophoresis and with an ability of serum to displace isolated copper-oxidized LDL from binding sites mediating degradation in mouse peritoneal macrophages. The coefficient of variance of the analysis is below 3%. It is concluded that this technique allows analysis of lipoprotein oxidation susceptibility in serum samples and may prove to be useful in clinical analysis of the lipoprotein oxidation susceptibility.
authors.affiliation: King Gustaf V Research Institute, Stockholm, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Regnström
authors.forename: K
authors.initials: K
authors.lastname: Ström
authors.forename: P
authors.initials: P
authors.lastname: Moldeus
authors.forename: J
authors.initials: J
authors.lastname: Nilsson
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D001665:Binding Sites; D002084:Butylated Hydroxytoluene / Q000494:pharmacology; D003300:Copper / Q000008:administration & dosage / Q000494:pharmacology*; D004587:Electrophoresis, Agar Gel; D006801:Humans; D007700:Kinetics; D008074:Lipoproteins / Q000097:blood*; D008077:Lipoproteins, LDL / Q000097:blood; D008264:Macrophages / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D051379:Mice; D010084:Oxidation-Reduction; D013056:Spectrophotometry, Ultraviolet; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014810:Vitamin E / Q000378:metabolism
chemical_list: D008074:Lipoproteins; D008077:Lipoproteins, LDL; D017392:Thiobarbituric Acid Reactive Substances; D014810:Vitamin E; D002084:Butylated Hydroxytoluene; D008315:Malondialdehyde; D003300:Copper; D001205:Ascorbic Acid