| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Molecular Medicine |
From the Biochemistry Group (A.C.T., S.R.T., R.S.), The Heart Research Institute, Camperdown, New South Wales, Australia; Department of Pharmacology and Toxicology (J.A.B., D.C.L.), College of Pharmacy, University of Arizona, Tucson, Ariz.
Correspondence to Professor Roland Stocker, The Heart Research Institute, 145 Missenden Rd, Camperdown, NSW, 2050, Australia. E-mail r.stocker{at}hri.org.au
Oxidation of low-density lipoproteins (LDL) is a key process in atherogenesis, and vitamin E (
-tocopherol, TOH) has received attention for its potential to attenuate the disease. Despite this, the type and extent of TOH oxidation and its relationship to lipid oxidation in the vessel wall where lesions develop remain unknown. Therefore, we measured oxidized lipids, TOH, and its oxidation products,
-tocopherylquinone (TQ), 2,3- and 5,6-epoxy-
-tocopherylquinones by gas chromatographymass spectrometry analysis in human lesions representing different stages of atherosclerosis. We also oxidized LDL in vitro to establish "footprints" of TOH oxidation product for different oxidants. The in vitro studies demonstrated that tocopherylquinone epoxides are the major products when LDL is exposed to the one-electron (ie, radical) oxidants, peroxyl radicals, and copper ions, whereas TQ preferentially accumulates with the two-electron (nonradical) oxidants, hypochlorite, and peroxynitrite. In human lesions, the relative extent of TOH oxidation was maximal early in the disease where it exceeded lipid oxidation. Independent of the disease stage, TQ was always the major oxidation product with all products together representing <20% of the total TOH present, and the oxidation product profile mirroring that formed during LDL oxidation by activated monocytes in the presence of nitrite. In contrast, oxidized lipid increased with increasing disease severity. These results suggest that two-electron oxidants are primarily responsible for TOH oxidation in the artery wall, and that the extent of TOH oxidation is limited yet substantial lipid oxidation takes place. This study may have important implications regarding antioxidant supplements aimed at preventing LDL oxidation and hence atherogenesis.
Key Words: tocopherol LDL oxidation atherogenesis hypochlorous acid
This article has been cited by other articles:
![]() |
B. Fletcher, K. Berra, P. Ades, L. T. Braun, L. E. Burke, J. L. Durstine, J. M. Fair, G. F. Fletcher, D. Goff, L. L. Hayman, et al. Managing Abnormal Blood Lipids: A Collaborative Approach Circulation, November 15, 2005; 112(20): 3184 - 3209. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. S. Bruno and M. G. Traber Cigarette Smoke Alters Human Vitamin E Requirements J. Nutr., April 1, 2005; 135(4): 671 - 674. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Stocker and J. F. Keaney Jr. Role of Oxidative Modifications in Atherosclerosis Physiol Rev, October 1, 2004; 84(4): 1381 - 1478. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Kontush, M. J. Chapman, and R. Stocker Vitamin E Is Not Deficient in Human Atherosclerotic Plaques Arterioscler Thromb Vasc Biol, July 1, 2004; 24(7): e139 - e140. [Full Text] [PDF] |
||||
![]() |
B. M. Rezk, G. R. M. M. Haenen, W. J. F. van der Vijgh, and A. Bast Lipoic Acid Protects Efficiently Only against a Specific Form of Peroxynitrite-induced Damage J. Biol. Chem., March 12, 2004; 279(11): 9693 - 9697. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Stocker and R. A O'Halloran Dealcoholized red wine decreases atherosclerosis in apolipoprotein E gene-deficient mice independently of inhibition of lipid peroxidation in the artery wall Am. J. Clinical Nutrition, January 1, 2004; 79(1): 123 - 130. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. K. Griendling and G. A. FitzGerald Oxidative Stress and Cardiovascular Injury: Part II: Animal and Human Studies Circulation, October 28, 2003; 108(17): 2034 - 2040. [Full Text] [PDF] |
||||
![]() |
A. Dutta and S. K. Dutta Vitamin E and its Role in the Prevention of Atherosclerosis and Carcinogenesis: A Review J. Am. Coll. Nutr., August 1, 2003; 22(4): 258 - 268. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Pankhurst, X. L. Wang, D. E. Wilcken, G. Baernthaler, U. Panzenbock, M. Raftery, and R. Stocker Characterization of specifically oxidized apolipoproteins in mildly oxidized high density lipoprotein J. Lipid Res., February 1, 2003; 44(2): 349 - 355. [Abstract] [Full Text] [PDF] |
||||
|
Circulation Research Home | Subscriptions | Archives | Feedback | Authors | Help | AHA Journals Home | Search Copyright © 2002 American Heart Association, Inc. All rights reserved. Unauthorized use prohibited. |