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Association of Nitrotyrosine Levels With Cardiovascular Disease and Modulation by Statin Therapy
Mehdi H. Shishehbor, DO;
Ronnier J. Aviles, MD;
Marie-Luise Brennan, PhD;
Xiaoming Fu, MS;
Marlene Goormastic, MPH;
Gregory L. Pearce, MS;
Noyan Gokce, MD;
John F. Keaney, Jr, MD;
Marc S. Penn, MD, PhD;
Dennis L. Sprecher, MD;
Joseph A. Vita, MD;
Stanley L. Hazen, MD, PhD
JAMA. 2003;289:1675-1680.
ABSTRACT
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Context Formation of nitric oxide–derived oxidants may serve as a mechanism linking inflammation to development of atherosclerosis. Nitrotyrosine, a specific marker for protein modification by nitric oxide–derived oxidants, is enriched in human atherosclerotic lesions and low-density lipoprotein (LDL) recovered from human atheroma.
Objectives To determine whether systemic levels of nitrotyrosine are associated with the prevalence of coronary artery disease (CAD) and are modulated by hydroxymethylglutaryl coenzyme-A reductase inhibitor (statin) therapy.
Design, Setting, and Patients A case-control and interventional study at 2 urban tertiary-care referral centers; recruitment for each was from June 1, 2001, until January 1, 2002. For the case-control study, 100 case-patients with established CAD and 108 patients with no clinically evident CAD were recruited consecutively. In the interventional study, participants aged 21 years or older with hypercholesterolemia (LDL cholesterol  130 mg/dL [3.5 mmol/L]) underwent nutrition and exercise counseling. Those whose levels did not decrease with 6 to 8 weeks were enrolled in the study (n = 35). For 12 weeks, they received 10 mg/d of oral atorvastatin therapy.
Main Outcome Measures In the case-control study, the association between systemic levels of protein-bound nitrotyrosine, CAD risk, and presence of CAD. In the interventional study, the change in nitrotyrosine, lipoprotein, and C-reactive protein (CRP) levels.
Results Nitrotyrosine levels were significantly higher among patients with CAD (median 9.1 µmol/mol [interquartile range, 4.8-13.8 µmol/mol] tyrosine vs 5.2 µmol/mol [interquartile range, 2.2-8.4 µmol/mol]; P<.001). Patients in the upper quartile of nitrotyrosine (29%; P<.001) had a higher odds of CAD compared with those in the lowest quartile (unadjusted odds ratio, 6.1; 95% confidence interval, 2.6-14.0; P<.001). In multivariate models adjusting for Framingham Global Risk Score and CRP, upper quartiles of nitrotyrosine remained associated with CAD (odds ratio, 4.4; 95% confidence interval, 1.8-10.6; P<.001). Statin therapy reduced nitrotyrosine levels significantly (25%; P<.02) with a magnitude similar to reductions in total cholesterol levels (25%; P<.001) and LDL particle number (29%; P<.001) yet were independent of alterations in lipoproteins and inflammatory markers like CRP.
Conclusions The findings from this preliminary study indicate that nitrotyrosine levels are associated with the presence of CAD and appear to be modulated by statin therapy. These results suggest a potential role for nitric oxide–derived oxidants as inflammatory mediators in CAD and may have implications for atherosclerosis risk assessment and monitoring of anti-inflammatory actions of statins.
INTRODUCTION
Nitric oxide is a vasodilator and inhibitor of platelet aggregation, leukocyte adhesion, and smooth muscle cell proliferation.1-3 However, under pathological conditions, nitric oxide may be converted into potent nitrating oxidants that promote oxidative damage, cell injury, and conversion of low-density lipoprotein (LDL) into an atherogenic form.1-5 One pathway for generating nitric oxide–derived oxidants involves interaction with superoxide anion, leading to formation of peroxynitrite. Peroxynitrite is a potent oxidant that promotes nitration of protein tyrosine residues producing a distinctive "molecular fingerprint" for nitric oxide–derived oxidants, nitrotyrosine.6-7 An alternative mechanism for generating nitric oxide–derived oxidants involves myeloperoxidase,7-11 a leukocyte-derived enzyme enriched in atherosclerotic lesions that serves as an independent predictor of cardiovascular risk.10 Although pathways that form nitrotyrosine have been mechanistically linked to atherosclerosis development, and nitrotyrosine levels are enriched in human atheroma,12-13 a role for plasma or serum levels of nitrotyrosine as a predictor of human coronary artery disease (CAD) has not yet been examined.
The pleiotropic effects of hydroxymethylglutaryl coenzyme-A reductase inhibitors (statins) are an area of intense interest.14-15 The pathways leading to generation of nitric oxide–derived oxidants and nitrotyrosine formation all require the formation of superoxide or its dismutation product, hydrogen peroxide.5-7,11 The major enzymatic sources for superoxide anion formation within vascular tissues involve leukocyte and vascular cell NAD(P)H oxidase complexes.5 Statins have been shown to inhibit superoxide anion formation within vascular cells by inhibiting isoprenylation of key NAD(P)H oxidase components,15-16 suggesting that statins may cause significant reductions in nitrotyrosine formation. Alternatively, statin-induced inhibition in isoprenylation of the small G-protein Rho leads to increased levels of endothelial cell nitric oxide synthase and enhanced nitric oxide production.15, 17 The net effect of statin therapy on formation of nitric oxide–derived oxidants in vivo is unclear. This study was performed to determine whether CAD is associated with increased systemic levels of nitrotyrosine and whether statin therapy would reduce these levels.
METHODS
Case-Control Study
We enrolled 208 individuals from 2 venues in Boston, Mass, from June 2001 until January 2002. Consecutive patients presenting to the cardiology section of the Boston Medical Center were enrolled. Simultaneously (and to increase recruitment of controls), consecutive area residents responding to advertisements in a community newspaper were recruited. The 100 case patients had a history of CAD, defined as documented myocardial infarction, coronary artery bypass graft surgery, percutaneous coronary intervention, or a stenosis of 50% or greater in 1 or more major coronary vessels on angiography. Some of the patients with CAD also had peripheral arterial disease (PAD), defined as an ankle-brachial index less than 0.9, intermittent claudication, and/or documented stenoses of peripheral or carotid arteries by angiography, magnetic resonance imaging, or ultrasound. Controls had no clinical history or symptoms suggestive of CAD or PAD. All participants gave written informed consent, and the institutional review board of Boston Medical Center approved the study protocol.
Prospective Intervention Study
We enrolled 35 consecutive patients from the Preventive Cardiology Clinic at the Cleveland Clinic Foundation from June 2001 until January 2002. Patients who were at least 21 years old, had no clinical evidence of CAD, PAD, or diabetes mellitus, were naive to statin therapy, and had low-density lipoprotein cholesterol (LDL-C) levels that were 130 mg/dL or higher (3.3 mmol/L) received counseling on nutritional and exercise interventions. If after 6 to 8 weeks LDL-C remained at 130 mg/dL or higher (3.3 mmol/L), patients were eligible for enrollment in the study. Fasting morning plasma samples were collected prior to initiation of therapy (baseline) and following 12 weeks of atorvastatin therapy (10 mg/d). All patients enrolled completed the study. Exclusion criteria included liver disease, renal insufficiency, or changes in medical therapy during the treatment period. All patients gave written informed consent, and the institutional review board at the Cleveland Clinic Foundation approved the study protocol.
Laboratory Analysis
General. Blood samples were collected into serum separator tubes (case-control study) or EDTA tubes (interventional study) from patients who had fasted overnight. Samples were centrifuged at 3500 rpm for 10 minutes, plasma/serum were recovered, and aliquots were stored at -80°C until analysis. Personnel blinded to clinical data performed all laboratory measurements. Lipoprotein/lipid profiles and high-sensitivity C-reactive protein (CRP) measurements were performed as previously described.18-19
Nitrotyrosine. Protein-bound nitrotyrosine levels were determined by stable isotope dilution liquid chromatography–electrospray ionization tandem mass spectrometry-based methods using an ion trap mass spectrometer (LCQ Deca, ThermoFinigann, San Jose, Calif), as previously described.11 Synthetic 3-nitro-[13C6]tyrosine (2 pmol) and [13C915N1]tyrosine (2 nmol) were added to protein pellets both as internal standards and to simultaneously monitor nitrotyrosine, tyrosine, and potential artifactual formation of nitrotyrosine during analyses.11 Nitrotyrosine content in samples is expressed as the molar ratio between nitrotyrosine and the precursor amino acid tyrosine. Protein-bound nitrotyrosine levels in plasma reproducibly were greater than that observed in serum, suggesting clotting factors represent preferential targets for nitration. Control studies demonstrated protein-bound nitrotyrosine levels within plasma of healthy subjects are stable over time, with coefficients of variance less than 15% for multiple independent repeated measures on different days or for comparisons made during more than 3 months apart.
Statistical Analysis
Case-Control Study. Nitrotyrosine levels were not normally distributed (Shapiro-Wilk test). Consequently, quartile-based methods were used for analyses, and summary measures were presented as median and interquartile range. Comparisons between cases and controls were made with  2 tests for categorical measures and Wilcoxon rank-sum tests for continuous measures. Trends were assessed with Cochran-Armitage tests.
Logistic regression models (SAS System, SAS Institute, Cary, NC) were used to calculate odds ratios (ORs) associated with the second, third, and highest quartile of nitrotyrosine compared with the lowest quartile for the indicated outcomes. Single adjustments were made for individual traditional CAD risk factors (age, sex, diabetes, hypertension, smoking [ever or current]), family history, total cholesterol, LDL-C, high-density lipoprotein cholesterol [HDL-C], triglycerides, CRP), and a modified Framingham Global Risk Score,10 alone and with CRP. Hosmer-Lemeshow goodness-of-fit tests were used to evaluate appropriate model fit. Associations among continuous variables were assessed with use of Spearman rank-correlation coefficient. Associations among categorical variables were assessed using Wilcoxon rank-sum tests.
The study was planned to have at least 100 patients per group, based on a logistic regression power calculation demonstrating that 198 patients would provide 80% power ( = .05) to detect an OR of 2.0 for elevated nitrotyrosine (upper quartile).
Interventional Study. Wilcoxon rank-sum test was used to analyze the differences between measurements at baseline and 12 weeks. Spearman rank-correlation coefficients were used to assess associations between both baseline and atorvastatin-induced changes in nitrotyrosine levels, lipoprotein profile measures, and CRP levels. Approximate 95% confidence intervals (CIs) were found using Fisher r-to-z transform. Multiple regression analyses were performed to determine factors associated with changes in nitrotyrosine levels.
RESULTS
Case-Control Study
Patient Demographics. Baseline characteristics of study participants are shown in Table 1. As expected, patients with CAD were older, more likely to be men, and more likely to have hypertension, diabetes mellitus, or family history of CAD. Patients with CAD also had increased triglyceride levels and CRP levels, and they were more likely to use lipid-lowering drugs and other cardiovascular medications.
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Table 1. Baseline Characteristics by Coronary Artery Disease Status
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Nitrotyrosine Levels and CAD. Nitrotyrosine levels were higher in patients with CAD compared with controls (median values, 9.1 µmol/mol tyrosine vs 5.2 µmol/mol tyrosine, respectively; P<.001; Table 1). Rates of CAD increased with higher nitrotyrosine quartiles (26% vs 58%, lowest vs highest quartiles; P<.001 for trend). Patients in the highest quartile of nitrotyrosine levels had increased risk of CAD compared with patients in the lowest quartile (Table 2; the unadjusted nitrotyrosine fourth quartile OR, 6.1; 95% CI, 2.6-14.0; P<.001). CAD rates were also higher with increasing CRP quartiles (25% vs 50%, lowest vs highest quartiles; P<.001 for trend). The proportion of patients with CAD was higher among those in the upper quartile of both nitrotyrosine and CRP levels compared with patients in the lower quartiles (76% vs 7%; P<.001).
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Table 2. Odds Ratios of Cardiovascular Disease Risk According to Quartiles of Nitrotyrosine
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Nitrotyrosine Levels and CAD Risk Factors. Nitrotyrosine levels correlated with age (r = 0.14, P = .03), fasting triglycerides (r = 0.14, P = .03), and CRP levels (r = 0.15, P = .02); however, these associations were small in magnitude and accounted for less than 5% of the observed variance in nitrotyrosine. There was no significant correlation between nitrotyrosine and LDL-C, HDL-C, or total cholesterol. Participants with diabetes had higher nitrotyrosine levels than those who did not have diabetes (median values, 9.6 µmol/mol tyrosine vs 5.7 µmol/mol tyrosine, respectively; P<.001).
Adjusted Models for Nitrotyrosine and CAD. Nitrotyrosine levels remained significantly associated with CAD following individual adjustments for age; sex; history of diabetes; current smoking; history of hypertension; and levels of HDL-C, LDL-C, triglyceride, and CRP with minimal changes observed in adjusted ORs and CIs (data not shown). After adjustment for the Framingham Global Risk Score, nitrotyrosine remained a robust predictor of presence of CAD (Table 2, Model 1; adjusted nitrotyrosine 4th quartile OR, 5.4; 95% CI, 2.0-14.3; P<.001). Addition of CRP to the model had little effect on the OR for nitrotyrosine as a predictor of CAD status (Table 2, Model 2; adjusted nitrotyrosine fourth quartile OR, 4.4; 95% CI, 1.8-10.6; P<.001). Likelihood ratio tests confirmed that introducing nitrotyrosine to multivariable prediction models that included established markers of cardiovascular risk (eg, Model 2, Table 2) significantly added to prediction for presence of CAD (2 = 10.42; P<.001).
Nitrotyrosine Levels and Atherosclerosis Burden. We also examined whether nitrotyrosine levels correlate with clinical evidence of atherosclerotic burden (ie, determine if the correlation of nitrotyrosine levels with atherosclerosis is even stronger in patients with more extensive atherosclerosis [CAD plus PAD]). Patients with CAD plus PAD demonstrated increases in prevalence of atherosclerosis with increasing nitrotyrosine quartiles (3% vs 46%, lowest vs highest quartiles; P<.001 for trend). Within this atherosclerosis-laden group, nitrotyrosine served as the strongest independent predictor associated with atherosclerosis risk following multivariable adjustments with Framingham Global Risk Score and CRP (adjusted nitrotyrosine fourth quartile OR, 25.4; 95% CI, 2.8-274; P<.001 [Table 2]; adjusted Framingham Global Risk Score OR, 1.25; 95% CI, 1.15-1.36; P<.001; adjusted CRP fourth quartile OR, 5.0; 95% CI, 2.1-16.6; P<.001).
Interventional Study
In the case-control study of the entire cohort (n = 208), nitrotyrosine levels demonstrated a tendency toward being lower in patients taking statins (P = .06), suggesting that statin therapy may reduce nitrotyrosin levels. This was directly assessed in an interventional study comprised of 35 patients with a mean (SD) of 54 (10) years, 49% of whom were men. Table 3 shows the lipid and lipoprotein levels, CRP, and nitrotyrosine levels at baseline and after taking orally 10 mg/d of atorvastatin for 12 weeks. Atorvastatin treatment reduced total cholesterol levels by 25%, LDL-C by 39%, and apolipoprotein B-100 by 29%. Statin-induced reductions in plasma nitrotyrosine levels (25%; P = .02) were similar in magnitude to decreases in total cholesterol and LDL particle number (ie, apolipoprotein B-100). A nonsignificant trend toward statin-induced reductions in CRP levels was also observed (11% reduction; P = .10).
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Table 3. Lipid Levels, High-Sensitivity C-Reactive Protein, and Nitrotyrosine at Baseline and After 12 Weeks of Treatment With Atorvastatin*
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No significant correlations were noted between baseline levels of nitrotyrosine, lipid parameters, and CRP. Furthermore, no significant correlations were noted between statin-induced changes in nitrotyrosine vs changes in lipoprotein and inflammatory markers including total cholesterol level (95% CI;  , -0.23 to 0.43), LDL-C (95% CI; , -0.2 to 0.45), HDL-C (95% CI; , -0.18 to 0.47), or CRP (95% CI, -0.22 to 0.44). In multivariable regression analysis, there was no significant association between change in nitrotyrosine levels and changes in levels of total cholesterol, LDL-C, HDL-C, and CRP (F-ratio = 0.71; P = .60).
COMMENT
The results of these preliminary studies suggest that nitrotyrosine, a marker specific for protein modification by nitric oxide–derived oxidants, may serve as an inflammatory marker for CAD. Systemic levels of protein-bound nitrotyrosine were associated with presence of CAD even following multivariable adjustments for traditional CAD risk factors and CRP. Importantly, statin therapy promoted significant reductions in nitrotyrosine levels that were similar in magnitude to reductions in total cholesterol and LDL particle number. Moreover, reductions in nitrotyrosine promoted by statin therapy were independent of reductions in lipid parameters and CRP. Taken together, these results suggest that nitrotyrosine measurements may prove useful both in assessing CAD status and for monitoring the anti-inflammatory effects of statins.
Numerous lines of evidence support potential links between formation of nitric oxide–derived oxidants and development of CAD. Current evidence suggests that an imbalance between superoxide and nitric oxide formation within diseased artery walls leads to a functional deficiency of nitric oxide, and consequent generation of nitric oxide-derived oxidants such as peroxynitrite and myeloperoxidase-generated reactive nitrogen species.1-5,9-11 Enhanced formation of superoxide in diseased artery walls may occur through vascular, endothelial (eg, nox), and leukocyte-derived NAD(P)H oxidase complexes,20-21 as well as nitric oxide synthase that is "uncoupled."22 Superoxide thus formed may interact with nitric oxide, resulting in formation of nitrating oxidants. Similarly, myeloperoxidase, a leukocyte-derived heme protein enriched in human atheroma,23-24 catalytically consumes nitric oxide as a physiological substrate.9, 25 Organ chamber studies and studies with myeloperoxidase knockout mice suggest that peroxidase enrichment at sites of inflammation, such as within the subendothelial space of a diseased vessel wall, inhibits nitric oxide-dependent vasodilation responses through mechanisms that lead to nitrotyrosine formation.26-27 Human monocytes have been shown to use both peroxynitrite and myeloperoxidase-dependent pathways for generating nitric oxide–derived oxidants, as monitored by nitrotyrosine formation.7 One consequence of these reactions appears to be the oxidative conversion of LDL into a high uptake form for macrophages, leading to cholesterol accumulation and foam cell formation.4 Alternative mechanisms have linked nitric oxide–derived oxidants to activation of matrix metalloproteases and development of unstable plaques28 and development of prothrombic states.29-30 The potential contributions of nitric oxide–derived oxidants to CAD development are thus numerous and varied.
In this study, therapy with low-dose atorvastatin significantly reduced nitrotyrosine levels. Statins promote systemic effects that extend beyond simply lowering cholesterol levels.1, 14-15 Statin-induced inhibition in superoxide formation has been shown in cultured vascular smooth muscle cells.16 We therefore hypothesized that significant reductions in nitrotyrosine would be noted since pathways leading to formation of nitric oxide–derived oxidants invariably require superoxide generation. The mechanism for decreased superoxide formation appears to involve inhibition of isoprenylation of the protein Rac, a key NAD(P)H oxidase component that normally requires isoprenylation for appropriate translocation to the plasma membrane surface during cell stimulation.15-16 Thus, in contrast to the modest alterations in CRP typically noted relative to those observed for lipoprotein and cholesterol levels,31-33 these results demonstrated that nitrotyrosine reductions were comparable in magnitude to those noted for total cholesterol or LDL particle number with administration of low-dose statin (Table 3). The growing appreciation of the pleiotropic actions of statins has underscored the requirement for new measures that quantify the anti-inflammatory properties of this widely used class of drugs. Our study suggests that systemic nitrotyrosine levels may serve as an independent measure of the anti-inflammatory actions of statins.
A corollary to these findings is that low-dose atorvastatin therapy promotes potent systemic antioxidant effects by suppressing formation of nitric oxide–derived oxidants. Further studies of the systemic antioxidant actions promoted by statin therapy are warranted. Recent randomized trials with antioxidant vitamins, particularly -tocopherol, have failed to demonstrate benefit against cardiovascular disease,34-35 and it is notable that -tocopherol is relatively ineffective at blocking the effects of nitric oxide–derived oxidants.36-38 It is tempting to speculate that interventional studies with statins, which have repeatedly demonstrated clinical benefits, have in fact also been "antioxidant" trials that used therapeutic agents able to suppress generation of more clinically relevant nitric oxide–derived oxidants.
Elevated nitrotyrosine levels in patients with diabetes were recently reported,39 a finding also observed in our cohort. Postprandial elevations in nitrotyrosine levels following consumption of a high fat or high glucose meal that were attenuated following simvastatin therapy were also recently reported.40 Although nitrotyrosine enrichment in human atherosclerotic lesions is well known from both immunohistochemical and mass spectrometry-based studies,12-13 our study is the first, to our knowledge, that directly correlates systemic levels of nitrotyrosine with presence of CAD and response to statin therapy. The cross-sectional (rather than longitudinal) design of the case-control study and the pilot nature of the intervention study are important limitations of our study. However, the results point toward promising potential clinical utility in use of nitrotyrosine levels as an adjunct for CAD risk stratification and monitoring of anti-inflammatory actions of statin therapy. Further evaluation of nitrotyrosine levels as a predictor of future cardiovascular events and outcomes and as a means of monitoring risk reduction attendant with statin therapy are warranted.
AUTHOR INFORMATION
Corresponding Author and Reprints: Stanley L. Hazen, MD, PhD, Cleveland Clinic Foundation, Cleveland, OH 44195 (e-mail: hazens{at}ccf.org).
Author Contributions: Study concept and design: Sprecher, Vita, Hazen.
Acquisition of data: Shishehbor, Aviles, Brennan, Fu, Gokce, Keaney, Vita, Hazen.
Analysis and interpretation of data: Shishehbor, Aviles, Brennan, Fu, Goormastic, Pearce, Gokce, Keaney, Penn, Sprecher, Vita, Hazen.
Drafting of the manuscript: Shishehbor, Aviles, Brennan, Pearce, Gokce, Penn, Vita, Hazen.
Critical revision of the manuscript for important intellectual content: Shishehbor, Aviles, Brennan, Fu, Goormastic, Keaney, Penn, Sprecher, Vita, Hazen.
Statistical expertise: Shishehbor, Aviles, Brennan, Goormastic, Pearce, Penn, Hazen.
Obtained funding: Vita, Hazen.
Administrative, technical, or material support: Brennan, Fu, Gokce, Hazen.
Study supervision: Gokce, Keaney, Hazen.
Funding/Support: This study was supported by grants HL70621, HL62526, and HL61878 (Dr Hazen) and HL60886 (Dr Vita) from the National Institutes of Health. Dr Shishehbor is a recipient of a Crile Fellowship Award, and Dr Aviles is a recipient of an American Heart Association Fellowship Award.
Acknowledgment: Mass spectrometry analyses were performed at the Cleveland Clinic Foundation Mass Spectrometry Core Facility, within the Center for Cardiovascular Diagnostics and Prevention.
Financial Disclosure: Dr Hazen is named as co-inventor on pending patents filed by the Cleveland Clinic Foundation that relate to the use of biomarkers for inflammatory and cardiovascular diseases.
Author Affiliations: Departments of Cell Biology (Drs Shishehbor, Aviles, Brennan, Penn, Sprecher, and Hazen and Ms Fu), Cardiovascular Medicine (Drs Aviles, Penn, Sprecher, and Hazen and Ms Goormastic and Mr Pearce) and the Center for Cardiovascular Diagnostics and Prevention (Drs Shishehbor, Aviles, Brennan, Penn, Sprecher, and Hazen and Ms Goormastic), the Cleveland ClinicFoundation, Cleveland, Ohio; and Evans Department of Medicine (Drs Gokce, Keaney, and Vita), Boston University School of Medicine, Boston, Mass.
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J. Clin. Endocrinol. Metab. 2009;94:2751-2756.
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Superoxide-mediated inactivation of nitric oxide and peroxynitrite formation by tobacco smoke in vascular endothelium: studies in cultured cells and smokers
Peluffo et al.
Am. J. Physiol. Heart Circ. Physiol. 2009;296:H1781-H1792.
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JUPITER to Earth: A statin helps people with normal LDL-C and high hs-CRP, but what does it mean?
SHISHEHBOR and HAZEN
Cleveland Clinic Journal of Medicine 2009;76:37-44.
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Fibrinogen {beta}-Chain Tyrosine Nitration Is a Prothrombotic Risk Factor
Parastatidis et al.
J. Biol. Chem. 2008;283:33846-33853.
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Poor 1-Year Outcomes After Percutaneous Coronary Interventions in Systemic Lupus Erythematosus: Report From the National Heart, Lung, and Blood Institute Dynamic Registry
Maksimowicz-McKinnon et al.
Circ Cardiovasc Interv 2008;1:201-208.
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Intermittent hypoxia has organ-specific effects on oxidative stress
Jun et al.
Am. J. Physiol. Regul. Integr. Comp. Physiol. 2008;295:R1274-R1281.
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Association between statin therapy and reductions in atrial fibrillation or flutter and inappropriate shock therapy
Bhavnani et al.
Europace 2008;10:854-859.
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Oscillating Glucose Is More Deleterious to Endothelial Function and Oxidative Stress Than Mean Glucose in Normal and Type 2 Diabetic Patients
Ceriello et al.
Diabetes 2008;57:1349-1354.
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Plasma Biomarkers of Oxidative Stress: Relationship to Lung Disease and Inhaled Nitric Oxide Therapy in Premature Infants
Ballard et al.
Pediatrics 2008;121:555-561.
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Glucose metabolism and hyperglycemia
Giugliano et al.
Am. J. Clin. Nutr. 2008;87:217S-222S.
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C-reactive Protein Level and Traditional Vascular Risk Factors in the Prediction of Carotid Stenosis
Mullenix et al.
Arch Surg 2007;142:1066-1071.
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White Blood Cells Telomere Length Is Shorter in Males With Type 2 Diabetes and Microalbuminuria
Tentolouris et al.
Diabetes Care 2007;30:2909-2915.
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Profound biopterin oxidation and protein tyrosine nitration in tissues of ApoE-null mice on an atherogenic diet: contribution of inducible nitric oxide synthase
Upmacis et al.
Am. J. Physiol. Heart Circ. Physiol. 2007;293:H2878-H2887.
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Increased Protein Nitration Burden in the Atherosclerotic Lesions and Plasma of Apolipoprotein A-I Deficient Mice
Parastatidis et al.
Circ. Res. 2007;101:368-376.
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Biochemistry of protein tyrosine nitration in cardiovascular pathology
Peluffo and Radi
Cardiovasc Res 2007;75:291-302.
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Telmisartan Shows an Equivalent Effect of Vitamin C in Further Improving Endothelial Dysfunction After Glycemia Normalization in Type 1 Diabetes
Ceriello et al.
Diabetes Care 2007;30:1694-1698.
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Prognostic Value and Echocardiographic Determinants of Plasma Myeloperoxidase Levels in Chronic Heart Failure
Tang et al.
J Am Coll Cardiol 2007;49:2364-2370.
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Simultaneous Control of Hyperglycemia and Oxidative Stress Normalizes Endothelial Function in Type 1 Diabetes
Ceriello et al.
Diabetes Care 2007;30:649-654.
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Retraction
Matschinsky
Diabetes 2006;55:2664-2664.
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Statin Use and Incident Nuclear Cataract
Klein et al.
JAMA 2006;295:2752-2758.
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Biomarkers of Cardiovascular Disease: Molecular Basis and Practical Considerations
Vasan
Circulation 2006;113:2335-2362.
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C-reactive protein and other emerging blood biomarkers to optimize risk stratification of vulnerable patients.
Tsimikas et al.
J Am Coll Cardiol 2006;47:C19-C31.
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Proteomic analysis of nitrated and 4-hydroxy-2-nonenal-modified serum proteins during aging.
Kim et al.
Journals of Gerontology Series A: Biological Sciences and Medical Sciences 2006;61:332-338.
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Consumption of Bing Sweet Cherries Lowers Circulating Concentrations of Inflammation Markers in Healthy Men and Women
Kelley et al.
J. Nutr. 2006;136:981-986.
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Biomarkers of Oxidative Damage in Human Disease
Dalle-Donne et al.
Clin. Chem. 2006;52:601-623.
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Women and Ischemic Heart Disease: Pathophysiologic Implications From the Women's Ischemia Syndrome Evaluation (WISE) Study and Future Research Steps
Quyyumi
J Am Coll Cardiol 2006;47:S66-S71.
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Atorvastatin Improves Left Ventricular Systolic Function and Serum Markers of Inflammation in Nonischemic Heart Failure
Sola et al.
J Am Coll Cardiol 2006;47:332-337.
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Activation of TLR-9 Induces IL-8 Secretion through Peroxynitrite Signaling in Human Neutrophils
Jozsef et al.
J. Immunol. 2006;176:1195-1202.
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Phagocytic NADPH Oxidase Overactivity Underlies Oxidative Stress in Metabolic Syndrome
Fortuno et al.
Diabetes 2006;55:209-215.
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Pulmonary and Systemic Nitric Oxide Metabolites in a Baboon Model of Neonatal Chronic Lung Disease
Munson et al.
Am. J. Respir. Cell Mol. Bio. 2005;33:582-588.
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An Apolipoprotein A-I Mimetic Works Best in the Presence of Apolipoprotein A-I
Navab et al.
Circ. Res. 2005;97:1085-1086.
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Tyrosine Modification Is Not Required for Myeloperoxidase-induced Loss of Apolipoprotein A-I Functional Activities
Peng et al.
J. Biol. Chem. 2005;280:33775-33784.
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Loss of Pentameric Symmetry in C-Reactive Protein Induces Interleukin-8 Secretion Through Peroxynitrite Signaling in Human Neutrophils
Khreiss et al.
Circ. Res. 2005;97:690-697.
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Iron Stores and Vascular Function in Voluntary Blood Donors
Zheng et al.
Arterioscler. Thromb. Vasc. Bio. 2005;25:1577-1583.
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Myeloperoxidase and Cardiovascular Disease
Nicholls and Hazen
Arterioscler. Thromb. Vasc. Bio. 2005;25:1102-1111.
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Effect of Atorvastatin and Irbesartan, Alone and in Combination, on Postprandial Endothelial Dysfunction, Oxidative Stress, and Inflammation in Type 2 Diabetic Patients
Ceriello et al.
Circulation 2005;111:2518-2524.
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Myeloperoxidase: friend and foe
Klebanoff
J. Leukoc. Biol. 2005;77:598-625.
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Cigarette Smoke Alters Human Vitamin E Requirements
Bruno and Traber
J. Nutr. 2005;135:671-674.
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Effects of Pramlintide on Postprandial Glucose Excursions and Measures of Oxidative Stress in Patients With Type 1 Diabetes
Ceriello et al.
Diabetes Care 2005;28:632-637.
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Effects of supplemental oxygen administration on coronary blood flow in patients undergoing cardiac catheterization
McNulty et al.
Am. J. Physiol. Heart Circ. Physiol. 2005;288:H1057-H1062.
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Acute hyperglycaemia: a 'new' risk factor during myocardial infarction
Ceriello
Eur Heart J 2005;26:328-331.
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Conditional Risk Factors for Atherosclerosis
Kullo and Ballantyne
Mayo Clin Proc. 2005;80:219-230.
ABSTRACT
Myeloperoxidase mediates neutrophil activation by association with CD11b/CD18 integrins
Lau et al.
Proc. Natl. Acad. Sci. USA 2005;102:431-436.
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Localization of Nitration and Chlorination Sites on Apolipoprotein A-I Catalyzed by Myeloperoxidase in Human Atheroma and Associated Oxidative Impairment in ABCA1-dependent Cholesterol Efflux from Macrophages
Zheng et al.
J. Biol. Chem. 2005;280:38-47.
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Postprandial Hyperglycemia and Diabetes Complications: Is It Time to Treat?
Ceriello
Diabetes 2005;54:1-7.
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Simvastatin Prevents Vascular Hyporeactivity During Inflammation
Pleiner et al.
Circulation 2004;110:3349-3354.
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The Moving Frontier in Nitric Oxide-Dependent Signaling
Nathan
Sci Signal 2004;2004:pe52-pe52.
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Antiinflammatory Properties of HDL
Barter et al.
Circ. Res. 2004;95:764-772.
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Human Atherosclerotic Intima and Blood of Patients with Established Coronary Artery Disease Contain High Density Lipoprotein Damaged by Reactive Nitrogen Species
Pennathur et al.
J. Biol. Chem. 2004;279:42977-42983.
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Role of Oxidative Modifications in Atherosclerosis
Stocker and Keaney
Physiol. Rev. 2004;84:1381-1478.
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Toward Broader Inclusion of Liquid Chromatography-Mass Spectrometry in the Clinical Laboratory
Kinter
Clin. Chem. 2004;50:1500-1502.
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Circulating free nitrotyrosine in obstructive sleep apnea
Svatikova et al.
Am. J. Physiol. Regul. Integr. Comp. Physiol. 2004;287:R284-R287.
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Atorvastatin Restores Endothelial Function in Normocholesterolemic Smokers Independent of Changes in Low-Density Lipoprotein
Beckman et al.
Circ. Res. 2004;95:217-223.
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Established and Emerging Plasma Biomarkers in the Prediction of First Atherothrombotic Events
Ridker et al.
Circulation 2004;109:IV-6-IV-19.
FULL TEXT
Thematic review series: The Pathogenesis of Atherosclerosis The oxidation hypothesis of atherogenesis: the role of oxidized phospholipids and HDL
Navab et al.
J. Lipid Res. 2004;45:993-1007.
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Albumin mediates the transcytosis of myeloperoxidase by means of caveolae in endothelial cells
Tiruppathi et al.
Proc. Natl. Acad. Sci. USA 2004;101:7699-7704.
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Pharmacologic Lipid-Lowering Therapy in Type 2 Diabetes Mellitus: Background Paper for the American College of Physicians
Vijan and Hayward
ANN INTERN MED 2004;140:650-658.
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Nitric oxide, oxidants, and protein tyrosine nitration
Radi
Proc. Natl. Acad. Sci. USA 2004;101:4003-4008.
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Identification of Free Radicals on Hemoglobin from its Self-peroxidation Using Mass Spectrometry and Immuno-spin Trapping: OBSERVATION OF A HISTIDINYL RADICAL
Deterding et al.
J. Biol. Chem. 2004;279:11600-11607.
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Pro-thrombotic State Induced by Post-translational Modification of Fibrinogen by Reactive Nitrogen Species
Vadseth et al.
J. Biol. Chem. 2004;279:8820-8826.
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Effect of Postprandial Hypertriglyceridemia and Hyperglycemia on Circulating Adhesion Molecules and Oxidative Stress Generation and the Possible Role of Simvastatin Treatment
Ceriello et al.
Diabetes 2004;53:701-710.
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The Role of Oxidative Stress-Altered Lipoprotein Structure and Function and Microinflammation on Cardiovascular Risk in Patients with Minor Renal Dysfunction
Kaysen and Eiserich
J. Am. Soc. Nephrol. 2004;15:538-548.
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Urinary 8-iso-Prostaglandin F2{alpha} as a Risk Marker in Patients With Coronary Heart Disease: A Matched Case-Control Study
Schwedhelm et al.
Circulation 2004;109:843-848.
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Dynamics of protein nitration in cells and mitochondria
Aulak et al.
Am. J. Physiol. Heart Circ. Physiol. 2004;286:H30-H38.
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Inflammatory/Antiinflammatory Properties of High-Density Lipoprotein Distinguish Patients From Control Subjects Better Than High-Density Lipoprotein Cholesterol Levels and Are Favorably Affected by Simvastatin Treatment
Ansell et al.
Circulation 2003;108:2751-2756.
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Isolevuglandins, a novel class of isoprostenoid derivatives, function as integrated sensors of oxidant stress and are generated by myeloperoxidase in vivo
POLIAKOV et al.
FASEB J. 2003;17:2209-2220.
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Statins Promote Potent Systemic Antioxidant Effects Through Specific Inflammatory Pathways
Shishehbor et al.
Circulation 2003;108:426-431.
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Coronary Artery Calcium and Cardiac Events: Is Electron-Beam Tomography Ready for Prime Time?
Weintraub
Circulation 2003;107:2528-2530.
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