Anti-oxidants - a protective role in cardiovascular disease?

Established risk factors for cardiovascular disease (CVD), such as hypertension, smoking and diabetes mellitus, explain only some of the observed variation in clinical events. This has maintained interest in other nutritional and biochemical factors that might contribute to the underlying pathophysiology of CVD. All of these risk factors are associated with increased oxidative stress in the vessel wall, which may contribute to CVD by several mechanisms. Studies in animal models of CVD have suggested that natural and synthetic anti-oxidants can prevent the development of clinical end points. These observations have generated the hypothesis that anti-oxidant therapy might also prevent CVD in human populations. This has been supported by epidemiological studies showing a negative correlation between circulating concentrations or dietary intake of natural anti-oxidant vitamins and CVD event rate. Many studies have also demonstrated a beneficial effect of anti-oxidants on surrogate markers of CVD such as endothelial function and lipoprotein oxidation. However, the results of large prospective randomised controlled intervention trials, mostly involving vitamin E in patients at increased risk of CVD, have been disappointing and have failed to demonstrate the anticipated benefits. This paper will critically examine the evidence and try to offer some explanation for the apparent failure of animal and epidemiological data to translate into meaningful clinical benefits.

[1]  A. Chait,et al.  Dietary antioxidants inhibit development of fatty streak lesions in the LDL receptor-deficient mouse. , 1998, Arteriosclerosis, thrombosis, and vascular biology.

[2]  R. Cohen,et al.  Oxidized low density lipoproteins cause contraction and inhibit endothelium-dependent relaxation in the pig coronary artery. , 1990, The Journal of clinical investigation.

[3]  E D Lehmann,et al.  Relation between number of cardiovascular risk factors/events and noninvasive Doppler ultrasound assessments of aortic compliance. , 1998, Hypertension.

[4]  P. Reaven,et al.  Effect of dietary antioxidant combinations in humans. Protection of LDL by vitamin E but not by beta-carotene. , 1993, Arteriosclerosis and thrombosis : a journal of vascular biology.

[5]  B. Adams-Huet,et al.  Dose-Response Comparison of RRR-α-Tocopherol and All-Racemic α-Tocopherol on LDL Oxidation , 1997 .

[6]  D. Webb,et al.  Impaired Coronary Tissue Plasminogen Activator Release Is Associated With Coronary Atherosclerosis and Cigarette Smoking: Direct Link Between Endothelial Dysfunction and Atherothrombosis , 2001, Circulation.

[7]  J L Witztum,et al.  Beyond cholesterol. Modifications of low-density lipoprotein that increase its atherogenicity. , 1989, The New England journal of medicine.

[8]  U. Steinbrecher,et al.  Oxidation of human low density lipoprotein results in derivatization of lysine residues of apolipoprotein B by lipid peroxide decomposition products. , 1987, The Journal of biological chemistry.

[9]  M. Gail,et al.  Nutrition intervention trials in Linxian, China: supplementation with specific vitamin/mineral combinations, cancer incidence, and disease-specific mortality in the general population. , 1993, Journal of the National Cancer Institute.

[10]  R. Stocker,et al.  Vitamin E in human low-density lipoprotein. When and how this antioxidant becomes a pro-oxidant. , 1992, The Biochemical journal.

[11]  T. Carew,et al.  Antiatherogenic effect of probucol unrelated to its hypocholesterolemic effect: evidence that antioxidants in vivo can selectively inhibit low density lipoprotein degradation in macrophage-rich fatty streaks and slow the progression of atherosclerosis in the Watanabe heritable hyperlipidemic rabbit. , 1987, Proceedings of the National Academy of Sciences of the United States of America.

[12]  G. Plotnick,et al.  Effect of antioxidant vitamins on the transient impairment of endothelium-dependent brachial artery vasoactivity following a single high-fat meal. , 1997, JAMA.

[13]  S. Moncada,et al.  ENDOGENOUS NITRIC OXIDE INHIBITS HUMAN PLATELET ADHESION TO VASCULAR ENDOTHELIUM , 1987, The Lancet.

[14]  S. Moncada,et al.  Superoxide anion is involved in the breakdown of endothelium-derived vascular relaxing factor , 1986, Nature.

[15]  K. Thompson,et al.  Dietary antioxidants do not reduce fatty streak formation in the C57BL/6 mouse atherosclerosis model. , 1998, Arteriosclerosis, thrombosis, and vascular biology.

[16]  D. Steinberg,et al.  Enhanced macrophage degradation of low density lipoprotein previously incubated with cultured endothelial cells: recognition by receptors for acetylated low density lipoproteins. , 1981, Proceedings of the National Academy of Sciences of the United States of America.

[17]  A. Quyyumi,et al.  Effect of copper-zinc superoxide dismutase on endothelium-dependent vasodilation in patients with essential hypertension. , 1995, Hypertension.

[18]  S. Ripatti,et al.  Randomised trial of α-tocopherol and β-carotene supplements on incidence of major coronary events in men with previous myocardial infarction , 1997, The Lancet.

[19]  J. Welch MRC/BHF Heart Protection Study of cholesterol-lowering therapy and of antioxidant vitamin supplementation in a wide range of patients at increased risk of coronary heart disease death: early safety and efficacy experience. , 1999, European heart journal.

[20]  S. Young,et al.  Probucol inhibits oxidative modification of low density lipoprotein. , 1986, The Journal of clinical investigation.

[21]  S. Rankin,et al.  Alpha-tocopherol consumption during low-density-lipoprotein oxidation. , 1990, The Biochemical journal.

[22]  C. Rice-Evans,et al.  A novel method for measuring antioxidant capacity and its application to monitoring the antioxidant status in premature neonates. , 1993, Clinical science.

[23]  N. Holbrook,et al.  Oxidants, oxidative stress and the biology of ageing , 2000, Nature.

[24]  A. Quyyumi,et al.  Effect of antioxidant vitamins on low density lipoprotein oxidation and impaired endothelium-dependent vasodilation in patients with hypercholesterolemia. , 1994, Journal of the American College of Cardiology.

[25]  J. Joseph,et al.  Inhibition of macrophage-dependent low density lipoprotein oxidation by nitric-oxide donors. , 1995, Journal of lipid research.

[26]  Robert Luben,et al.  Relation between plasma ascorbic acid and mortality in men and women in EPIC-Norfolk prospective study: a prospective population study , 2001, The Lancet.

[27]  H. Alessio,et al.  Oxygen-radical absorbance capacity assay for antioxidants. , 1993, Free radical biology & medicine.

[28]  S. Yusuf,et al.  Vitamin E supplementation and cardiovascular events in high-risk patients. , 2000, The New England journal of medicine.

[29]  T. Andersson,et al.  Vitamin E reverses cholesterol-induced endothelial dysfunction in the rabbit coronary circulation. , 1994, Atherosclerosis.

[30]  S. Rankin,et al.  α-tocopherol consumption during low-density-lipoprotein oxidation , 1990 .

[31]  G. Walldius,et al.  Antioxidants and atherosclerosis progression: unresolved questions. , 1994, Current opinion in lipidology.

[32]  P. Brecher,et al.  Superoxide anion from the adventitia of the rat thoracic aorta inactivates nitric oxide. , 1998, Circulation research.

[33]  A. Hamsten,et al.  Susceptibility to low-density lipoprotein oxidation and coronary atherosclerosis in man , 1992, The Lancet.

[34]  C. Walling,et al.  Autoxidation of lipids and antioxidation by alpha-tocopherol and ubiquinol in homogeneous solution and in aqueous dispersions of lipids: unrecognized consequences of lipid particle size as exemplified by oxidation of human low density lipoprotein. , 1993, Proceedings of the National Academy of Sciences of the United States of America.

[35]  M. Boaz,et al.  Secondary prevention with antioxidants of cardiovascular disease in endstage renal disease (SPACE): randomised placebo-controlled trial , 2000, The Lancet.

[36]  D. Harrison,et al.  Probucol improves endothelial-dependent relaxation and decreases vascular superoxide production in cholesterol-fed rabbits. , 1998, The American journal of the medical sciences.

[37]  U. Beisiegel,et al.  The effect of pharmacological doses of different antioxidants on oxidation parameters and atherogenesis in hyperlipidaemic rabbits. , 2001, Atherosclerosis.

[38]  S. Wolff,et al.  Oxidative glycation and free radical production: a causal mechanism of diabetic complications. , 1991, Free radical research communications.

[39]  B. Ames,et al.  Ascorbate is an outstanding antioxidant in human blood plasma. , 1989, Proceedings of the National Academy of Sciences of the United States of America.

[40]  J. Packer,et al.  Direct observation of a free radical interaction between vitamin E and vitamin C , 1979, Nature.

[41]  D. Harrison,et al.  Hypercholesterolemia increases endothelial superoxide anion production. , 1993, The Journal of clinical investigation.

[42]  H. Nakamura,et al.  Effect of supplementation with vitamin E on LDL oxidizability and prevention of atherosclerosis , 1998, BioFactors.

[43]  D. Webb,et al.  An in vivo Model for the Assessment of Acute Fibrinolytic Capacity of the Endothelium , 1997, Thrombosis and Haemostasis.

[44]  S. Maxwell,et al.  Comparison of antioxidant activity in lipoprotein fractions from insulin-dependent diabetics and healthy controls. , 1997, Atherosclerosis.

[45]  D. Giugliano,et al.  Anti-oxidants show an anti-hypertensive effect in diabetic and hypertensive subjects. , 1991, Clinical science.

[46]  R. Ostlund,et al.  The effects of native LDL and oxidized LDL on EDRF bioactivity and nitric oxide production in vascular endothelium. , 1994, The Journal of laboratory and clinical medicine.

[47]  H. Esterbauer,et al.  The role of lipid peroxidation and antioxidants in oxidative modification of LDL. , 1992, Free radical biology & medicine.

[48]  S. Ripatti,et al.  Randomised trial of alpha-tocopherol and beta-carotene supplements on incidence of major coronary events in men with previous myocardial infarction. , 1997, Lancet.

[49]  E. Rimm,et al.  Vitamin E consumption and the risk of coronary heart disease in men. , 1993, The New England journal of medicine.

[50]  T. Andersson,et al.  Dietary vitamin E increases the resistance to lipoprotein oxidation and attenuates endothelial dysfunction in the cholesterol-fed rabbit. , 1994, Atherosclerosis.

[51]  B. Halliwell,et al.  Free radicals in biology and medicine , 1985 .

[52]  H. Blackburn,et al.  Dietary saturated and trans fatty acids and cholesterol and 25-year mortality from coronary heart disease: the Seven Countries Study. , 1995, Preventive medicine.

[53]  H. Griffiths,et al.  Measuring in vivo oxidative damage : a practical approach , 2000 .

[54]  S. Maxwell,et al.  Enhanced chemiluminescent assay for antioxidant capacity in biological fluids , 1992 .

[55]  J. Woodside,et al.  Antioxidants in health and disease , 2001, Journal of clinical pathology.

[56]  B. Babior,et al.  Oxygen-dependent microbial killing by phagocytes (second of two parts). , 1978, The New England journal of medicine.

[57]  Trevor A. Mori,et al.  Dietary Cosupplementation With Vitamin E and Coenzyme Q10 Inhibits Atherosclerosis in Apolipoprotein E Gene Knockout Mice , 2001, Arteriosclerosis, thrombosis, and vascular biology.

[58]  K. Metze,et al.  Effects of vitamin E on endothelium-dependent coronary flow in hypercholesterolemic dogs. , 1996, Atherosclerosis.

[59]  S. Maxwell,et al.  Red wine and antioxidant activity in serum , 1994, The Lancet.

[60]  G. Newton,et al.  Vitamin C Augments the Inotropic Response to Dobutamine in Humans With Normal Left Ventricular Function , 2001, Circulation.

[61]  U. Garbin,et al.  Predisposition to LDL oxidation in patients with and without angiographically established coronary artery disease. , 1993, Atherosclerosis.

[62]  J L Witztum,et al.  Evidence for the presence of oxidatively modified low density lipoprotein in atherosclerotic lesions of rabbit and man. , 1989, The Journal of clinical investigation.

[63]  S. Yusuf,et al.  Heart Outcomes Prevention Evaluation Study Investigators. Effects of an angiotensin-converting-enzyme inhibitor, ramipril, on cardiovascular events in high-risk patients. N Engl J Med 2000;342:145-53. , 2000 .

[64]  J. Loscalzo,et al.  Low-dose alpha-tocopherol improves and high-dose alpha-tocopherol worsens endothelial vasodilator function in cholesterol-fed rabbits. , 1994, The Journal of clinical investigation.

[65]  P. Richardson,et al.  Reduction of platelet adhesiveness by vitamin E supplementation in humans. , 1988, Thrombosis research.

[66]  Kukin Ml The Heart Outcomes Prevention Evaluation Study. , 2001, Current cardiology reports.

[67]  S. Maxwell Antioxidant Vitamin Supplements , 1999, Drug safety.

[68]  A. Yeung,et al.  The effect of cholesterol-lowering and antioxidant therapy on endothelium-dependent coronary vasomotion. , 1995, The New England journal of medicine.

[69]  M. Rich Uric acid: is it a risk factor for cardiovascular disease? , 2000, The American journal of cardiology.

[70]  D. Wood,et al.  Risk of angina pectoris and plasma concentrations of vitamins A, C, and E and carotene , 1991, The Lancet.

[71]  M. Catalano,et al.  Increased superoxide anion production in humans: a possible mechanism for the pathogenesis of hypertension. , 1996, Journal of human hypertension.

[72]  J. Sasaki,et al.  Does superoxide underlie the pathogenesis of hypertension? , 1991, Proceedings of the National Academy of Sciences of the United States of America.

[73]  D. Steinberg,et al.  Oxidatively modified low density lipoproteins: a potential role in recruitment and retention of monocyte/macrophages during atherogenesis. , 1987, Proceedings of the National Academy of Sciences of the United States of America.

[74]  A. Hassid,et al.  Nitric oxide-generating vasodilators and 8-bromo-cyclic guanosine monophosphate inhibit mitogenesis and proliferation of cultured rat vascular smooth muscle cells. , 1989, The Journal of clinical investigation.

[75]  J. George,et al.  Dietary β-Carotene and α-Tocopherol Combination Does Not Inhibit Atherogenesis in an ApoE–Deficient Mouse Model , 1999 .

[76]  D. Albanes,et al.  The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. , 1994, The New England journal of medicine.

[77]  P. Chowienczyk,et al.  Effects of vitamin C and of a cell permeable superoxide dismutase mimetic on acute lipoprotein induced endothelial dysfunction in rabbit aortic rings , 1999, British journal of pharmacology.

[78]  A. Dominiczak,et al.  Oxidative stress and vascular damage in hypertension , 2001, Current opinion in nephrology and hypertension.

[79]  A. Barnett,et al.  Antioxidant status in patients with uncomplicated insulin‐dependent and non‐insulin‐dependent diabetes mellitus , 1997, European journal of clinical investigation.

[80]  B. Hoffman,et al.  Inactivation of endothelial derived relaxing factor by oxidized lipoproteins. , 1992, The Journal of clinical investigation.

[81]  E. Feskens,et al.  Dietary antioxidant flavonoids and risk of coronary heart disease: the Zutphen Elderly Study , 1993, The Lancet.

[82]  S. Aust,et al.  Role of metals in oxygen radical reactions. , 1985, Journal of free radicals in biology & medicine.

[83]  A. Wheatley,et al.  &bgr;2-Adrenoceptor Polymorphism Determines Vascular Reactivity in Humans , 2000, Hypertension.

[84]  D. Harrison,et al.  Diet-induced atherosclerosis increases the release of nitrogen oxides from rabbit aorta. , 1990, The Journal of clinical investigation.

[85]  J. Salonen,et al.  Autoantibody against oxidised LDL and progression of carotid atherosclerosis , 1992, The Lancet.

[86]  J. Manson,et al.  Lack of effect of long-term supplementation with beta carotene on the incidence of malignant neoplasms and cardiovascular disease. , 1996, The New England journal of medicine.

[87]  E. Parks,et al.  Inhibition of oxidation of human low-density lipoprotein by phenolic substances in red wine , 1993, The Lancet.

[88]  S. Weiss Tissue destruction by neutrophils. , 1989, The New England journal of medicine.

[89]  P. Puska,et al.  Inverse correlation between plasma vitamin E and mortality from ischemic heart disease in cross-cultural epidemiology. , 1991, The American journal of clinical nutrition.

[90]  L. Appel,et al.  Association between cigarette smoking and lipid peroxidation in a controlled feeding study. , 1997, Circulation.

[91]  O. Aruoma,et al.  Stimulation of lipid peroxidation and hydroxyl-radical generation by the contents of human atherosclerotic lesions. , 1992, The Biochemical journal.

[92]  J. Kluger Beyond cholesterol. , 1997, Time.

[93]  A. Quyyumi,et al.  Abnormal endothelium-dependent vascular relaxation in patients with essential hypertension. , 1990, The New England journal of medicine.

[94]  S. Maxwell,et al.  Measurement of antioxidant activity in lipoproteins using enhanced chemiluminescence. , 1994, Atherosclerosis.

[95]  E. Orringer,et al.  An ascorbate-mediated transmembrane-reducing system of the human erythrocyte. , 1979, The Journal of clinical investigation.

[96]  R. Stocker,et al.  Time-dependent changes to lipids and antioxidants in plasma and aortas of apolipoprotein E knockout mice. , 1999, Journal of lipid research.

[97]  M. Brown,et al.  Lipoprotein metabolism in the macrophage: implications for cholesterol deposition in atherosclerosis. , 1983, Annual review of biochemistry.

[98]  S. Maxwell,et al.  Antioxidant status in controlled and uncontrolled hypertension and its relationship to endothelial damage. , 1994, Journal of human hypertension.

[99]  G. Hatch,et al.  Alteration of lysophosphatidylcholine content in low density lipoprotein after oxidative modification: relationship to endothelium dependent relaxation. , 1994, Cardiovascular research.

[100]  M. Woodward,et al.  The Scottish Heart Health Study. Dietary intake by food frequency questionnaire and odds ratios for coronary heart disease risk. II. The antioxidant vitamins and fibre. , 1992, European journal of clinical nutrition.

[101]  G. Watts,et al.  Impaired endothelium-dependent vasodilation of forearm resistance vessels in hypercholesterolaemia , 1992, The Lancet.

[102]  S. L. Hazen,et al.  Reactive Nitrogen Intermediates Promote Low Density Lipoprotein Oxidation in Human Atherosclerotic Intima* , 1997, The Journal of Biological Chemistry.

[103]  P. Nataf,et al.  Effect of the oxidation state of LDL on the modulation of arterial vasomotor response in vitro. , 1997, Atherosclerosis.

[104]  P. Groop,et al.  Chronic hyperglycemia impairs endothelial function and insulin sensitivity via different mechanisms in insulin-dependent diabetes mellitus. , 1996, Circulation.

[105]  GISSI-Prevenzione Investigators,et al.  Dietary supplementation with n-3 polyunsaturated fatty acids and vitamin E after myocardial infarction: results of the GISSI-Prevenzione trial , 1999, The Lancet.

[106]  M. Brown,et al.  A Randomised Controlled Trial of Vitamin E in Patients with Coronary Disease: The Cambridge Heart Antioxidant Study (CHAOS) , 1996 .

[107]  S. Hazen,et al.  Myeloperoxidase-generated reactive nitrogen species convert LDL into an atherogenic form in vitro. , 1999, The Journal of clinical investigation.

[108]  L. Prónai,et al.  Low superoxide scavenging activity associated with enhanced superoxide generation by monocytes from male hypertriglyceridemia with and without diabetes. , 1991, Atherosclerosis.

[109]  R Busse,et al.  Effects of native and oxidized low density lipoproteins on formation and inactivation of endothelium-derived relaxing factor. , 1991, Arteriosclerosis and thrombosis : a journal of vascular biology.

[110]  B. Ames,et al.  Uric acid provides an antioxidant defense in humans against oxidant- and radical-caused aging and cancer: a hypothesis. , 1981, Proceedings of the National Academy of Sciences of the United States of America.

[111]  W. A. Bradley,et al.  Superoxide and peroxynitrite in atherosclerosis. , 1994, Proceedings of the National Academy of Sciences of the United States of America.