title: Virtually same oxidizability of LDL but higher Lp(a) levels in arterial compared to venous plasma.
abstract: Plaque formation is confined to the arterial trunk. We assumed that due to the higher aeration of arterial compared to venous blood, higher levels of the atherogenic agent oxidized LDL might be present in arteries, contributing to plaque formation. We aimed to compare (i) the basal oxidative status of LDL in arterial and venous blood and (ii) the susceptibility of arterial and venous LDL to oxidation. The basal oxidative status of LDL was determined by measuring lipid hydroperoxide (LPO) concentrations, plasma levels of auto-antibodies against oxidized LDL, and by measuring oxidation-specific epitopes on LDL particles. The oxidizability of arterial vs. venous LDL (catalyzed by copper) was estimated by monitoring the time-course of conjugated dienes formation. Interestingly, we found the same basal oxidative status of LDL in arterial and venous plasma. LPO concentrations and levels of auto-antibodies against oxidized LDL were similar in arterial and venous plasma and amounts of oxidation-specific epitopes were similar on the respective LDL particles. Moreover, we found similar susceptibilities of arterial and venous LDL to (copper-mediated) oxidation. Lag-times until the onset of conjugated diene formation were slightly shorter in arterial compared to venous LDL in the presence of 5 μM, but not in the presence of 1 μM CuCl2. Additionally, we found significantly higher levels of the atherogenic lipoprotein(a) in arterial plasma. We conclude that not higher oxidizability of arterial LDL but higher arterial lipoprotein(a) levels might help to explain why sclerosis is confined to the arterial trunk.
authors.affiliation: Institute of Physiological Chemistry, Medical University of Graz, Harrachgasse 21/II, Graz A-8010, Austria.
authors.forename: Gerd
authors.initials: G
authors.lastname: Hoerl
authors.affiliation: Institute of Physiological Chemistry, Medical University of Graz, Harrachgasse 21/II, Graz A-8010, Austria.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Ledinski
authors.affiliation: Institute of Physiological Chemistry, Medical University of Graz, Harrachgasse 21/II, Graz A-8010, Austria.
authors.forename: Gerd
authors.initials: G
authors.lastname: Kager
authors.affiliation: Department of Surgery, Medical University of Graz, Graz, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Thalhammer
authors.affiliation: Department of Pediatrics, Medical University of Graz, Graz, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Koestenberger
authors.affiliation: Institute of Physiological Chemistry, Medical University of Graz, Harrachgasse 21/II, Graz A-8010, Austria.
authors.forename: Guenther
authors.initials: G
authors.lastname: Juergens
authors.affiliation: Department of Angiology, Medical University of Graz, Graz, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Gary
authors.affiliation: Institute of Physiological Chemistry, Medical University of Graz, Harrachgasse 21/II, Graz A-8010, Austria. Electronic address: gerhard.cvirn@medunigraz.at.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Cvirn
mesh_terms: D000368:Aged; D000911:Antibodies, Monoclonal / Q000276:immunology; D001158:Arteries / Q000378:metabolism*; D001323:Autoantibodies / Q000097:blood; D003300:Copper / Q000737:chemistry; D000939:Epitopes / Q000032:analysis / Q000276:immunology; D005260:Female; D006801:Humans; D007118:Immunoassay; D008077:Lipoproteins, LDL / Q000097:blood*; D008297:Male; D008875:Middle Aged; D014680:Veins / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D000939:Epitopes; D008077:Lipoproteins, LDL; C099252:oxidized low density lipoprotein; D003300:Copper; C029892:cupric chloride
keywords: Conjugated diene formation; Lipid peroxidation; Lipoprotein(a); Oxidation-specific immune epitopes; Plaque formation