Effects of bezafibrate and simvastatin on endothelial activation and lipid peroxidation in hypercholesterolemia: evidence of different vascular protection by different lipid-lowering treatments

Cocoa Consumption Decreases Oxidative Stress, Proinflammatory Mediators and Lipid Peroxidation in Healthy Subjects: A Randomized Placebo-Controlled Dose-Response Clinical Trial

INTRODUCTION

Cocoa flavonoids have been described to reduce the cardiovascular risk. Nevertheless, the involved mechanisms should be clarified and the dose-effect relation has never been evaluated.

AIM

To investigate the dose-dependent effects of cocoa flavonoids on markers of endothelial and platelet activation and oxidative stress.

METHODS

According to a randomized, double-blind, controlled, cross-over design, 20 healthy nonsmokers were assigned to receive either five treatments with daily intake of 10 g cocoa (0, 80, 200, 500 and 800 mg cocoa flavonoids/day) in five periods lasting 1 week each.

RESULTS

Compared with flavonoid-free cocoa control, cocoa reduced sICAM-1 mean values [from 1190.2 to 1123.0; 906.3; 741.7 and 625.6 pg/mL (p = 0.0198 and p = 0.0016, for 500 and 800 mg respectively], sCD40L mean values [from 218.8 to 210.2; 165.5; 134.5 and 128.4 pg/mL (p = 0.023 and p = 0.013, for 500 and 800 mg respectively] and 8-isoprostanes F2 mean values [from 4703.9 to 4670.7; 2000.1; 2098.4 and 2052.3 pg/mL (p = 0.025; p = 0.034 and p = 0.029, for 200, 500 and 800 mg respectively)].

CONCLUSIONS

In our study we observed that short-term cocoa consumption improved proinflammatory mediators, lipid peroxidation and oxidative stress with a significant effect for higher dosages of flavonoids. Our findings suggest cocoa might be a valid tool for dietary intervention in prevention of atherosclerosis.

Platelet Redox Imbalance in Hypercholesterolemia: A Big Problem for a Small Cell

The imbalance between reactive oxygen species (ROS) synthesis and their scavenging by anti-oxidant defences is the common soil of many disorders, including hypercholesterolemia. Platelets, the smallest blood cells, are deeply involved in the pathophysiology of occlusive arterial thrombi associated with myocardial infarction and stroke. A great deal of evidence shows that both increased intraplatelet ROS synthesis and impaired ROS neutralization are implicated in the thrombotic process. Hypercholesterolemia is recognized as cause of atherosclerosis, cerebro- and cardiovascular disease, and, closely related to this, is the widespread acceptance that it strongly contributes to platelet hyperreactivity via direct oxidized LDL (oxLDL)-platelet membrane interaction via scavenger receptors such as CD36 and signaling pathways including Src family kinases (SFK), mitogen-activated protein kinases (MAPK), and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. In turn, activated platelets contribute to oxLDL generation, which ends up propagating platelet activation and thrombus formation through a mechanism mediated by oxidative stress. When evaluating the effect of lipid-lowering therapies on thrombogenesis, a large body of evidence shows that the effects of statins and proprotein convertase subtilisin/kexin type 9 inhibitors are not limited to the reduction of LDL-C but also to the down-regulation of platelet reactivity mainly by mechanisms sensitive to intracellular redox balance. In this review, we will focus on the role of oxidative stress-related mechanisms as a cause of platelet hyperreactivity and the pathophysiological link of the pleiotropism of lipid-lowering agents to the beneficial effects on platelet function.

Discovery of new therapeutic redox targets for cardioprotection against ischemia/reperfusion injury and heart failure

Global epidemiological studies reported a shift from maternal/infectious communicable diseases to chronic non-communicable diseases and a major part is attributable to atherosclerosis and metabolic disorders. Accordingly, ischemic heart disease was identified as a leading risk factor for global mortality and morbidity with a prevalence of 128 million people. Almost 9 million premature deaths can be attributed to ischemic heart disease and subsequent acute myocardial infarction and heart failure, also representing a substantial socioeconomic burden. As evidenced by typical oxidative stress markers such as lipid peroxidation products or oxidized DNA/RNA bases, the formation of reactive oxygen species by various sources (NADPH oxidases, xanthine oxidase and mitochondrial resperatory chain) plays a central role for the severity of ischemia/reperfusion damage. The underlying mechanisms comprise direct oxidative damage but also adverse redox-regulation of kinase and calcium signaling, inflammation and cardiac remodeling among others. These processes and the role of reactive oxygen species are discussed in the present review. We also present and discuss potential targets for redox-based therapies that are either already established in the clinics (e.g. guanylyl cyclase activators and stimulators) or at least successfully tested in preclinical models of myocardial infarction and heart failure (mitochondria-targeted antioxidants). However, reactive oxygen species have not only detrimental effects but are also involved in essential cellular signaling and may even act protective as seen by ischemic pre- and post-conditioning or eustress - which makes redox therapy quite challenging.

Revisiting pharmacology of oxidative stress and endothelial dysfunction in cardiovascular disease: Evidence for redox-based therapies

According to the latest Global Burden of Disease Study data, non-communicable diseases in general and cardiovascular disease (CVD) in particular are the leading cause of premature death and reduced quality of life. Demographic shifts, unhealthy lifestyles and a higher burden of adverse environmental factors provide an explanation for these findings. The expected growing prevalence of CVD requires enhanced research efforts for identification and characterisation of novel therapeutic targets and strategies. Cardiovascular risk factors including classical (e.g. hypertension, diabetes, hypercholesterolaemia) and non-classical (e.g. environmental stress) factors induce the development of endothelial dysfunction, which is closely associated with oxidant stress and vascular inflammation and results in CVD, particularly in older adults. Most classically successful therapies for CVD display vasoprotective, antioxidant and anti-inflammatory effects, but were originally designed with other therapeutic aims. So far, only a few 'redox drugs' are in clinical use and many antioxidant strategies have not met expectations. With the present review, we summarise the actual knowledge on CVD pathomechanisms, with special emphasis on endothelial dysfunction, adverse redox signalling and oxidative stress, highlighting the preclinical and clinical evidence. In addition, we provide a brief overview of established CVD therapies and their relation to endothelial dysfunction and oxidative stress. Finally, we discuss novel strategies for redox-based CVD therapies trying to explain why, despite a clear link between endothelial dysfunction and adverse redox signalling and oxidative stress, redox- and oxidative stress-based therapies have not yet provided a breakthrough in the treatment of endothelial dysfunction and CVD.

Therapeutic Effects of PPAR α on Neuronal Death and Microvascular Impairment

Peroxisome-proliferator activated receptor-alpha (PPARα) is a broadly expressed nuclear hormone receptor and is a transcription factor for diverse target genes possessing a PPAR response element (PPRE) in the promoter region. The PPRE is highly conserved, and PPARs thus regulate transcription of an extensive array of target genes involved in energy metabolism, vascular function, oxidative stress, inflammation, and many other biological processes. PPARα has potent protective effects against neuronal cell death and microvascular impairment, which have been attributed in part to its antioxidant and anti-inflammatory properties. Here we discuss PPARα's effects in neurodegenerative and microvascular diseases and also recent clinical findings that identified therapeutic effects of a PPARα agonist in diabetic microvascular complications.

Interactions of commonly used dietary supplements with cardiovascular drugs: a systematic review

BACKGROUND

The objective of this systematic review was to examine the benefits, harms and pharmacokinetic interactions arising from the co-administration of commonly used dietary supplements with cardiovascular drugs. Many patients on cardiovascular drugs take dietary supplements for presumed benefits and may be at risk for adverse supplement-drug interactions.

METHODS

The Allied and Complementary Medicine Database, the Cochrane Library, EMBASE, International Bibliographic Information on Dietary Supplements and MEDLINE were searched from the inception of the review to October 2011. Grey literature was also reviewed.Two reviewers independently screened records to identify studies comparing a supplement plus cardiovascular drug(s) with the drug(s) alone. Reviewers extracted data using standardized forms, assessed the study risk of bias, graded the strength of evidence and reported applicability.

RESULTS

Evidence was obtained from 65 randomized clinical trials, 2 controlled clinical trials and 1 observational study. With only a few small studies available per supplement, evidence was insufficient for all predefined gradable clinical efficacy and harms outcomes, such as mortality and serious adverse events. One long-term pragmatic trial showed no benefit from co-administering vitamin E with aspirin on a composite cardiovascular outcome. Evidence for most intermediate outcomes was insufficient or of low strength, suggesting no effect. Incremental benefits were noted for triglyceridemia with omega-3 fatty acid added to statins; and there was an improvement in levels of high-density lipoprotein cholesterol with garlic supplementation when people also consumed nitrates

CONCLUSIONS

Evidence of low-strength indicates benefits of omega-3 fatty acids (plus statin, or calcium channel blockers and antiplatelets) and garlic (plus nitrates or warfarin) on triglycerides and HDL-C, respectively. Safety concerns, however, persist.

Keishibukuryogan (gui-zhi-fu-ling-wan), a Kampo formula, decreases disease activity and soluble vascular adhesion molecule-1 in patients with rheumatoid arthritis

An increasing death rate due to cardiovascular disease in patients with rheumatoid arthritis (RA) has been reported. Keishibukuryogan (KBG) is a traditional Chinese/Japanese (Kampo) formula that has been administered to patients with blood stagnation, e.g. thrombotic disease and atherosclerosis. The objective of this study was to evaluate the efficacy of KBG on disease activity and endothelial dysfunction in RA patients. Sixteen RA patients were enrolled and administered KBG (12 g per day) for 12 weeks in addition to continuing other drugs. The disease activity of RA was assessed by modified disease activity scores for 28 joints (DAS(28)). Plasma levels of adhesion molecules, soluble E-selectin (sE-selectin), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) were evaluated. C-reactive protein (CRP), inflammatory cytokines (IL-1beta, IL-6 and TNF-alpha) and lipid peroxide (LPO) were also evaluated. Fourteen patients completed the study. The disease activity of RA, tender joint count, swollen joint count and DAS(28) decreased significantly. Among adhesion molecules, only sVCAM-1 decreased significantly. LPO also decreased significantly, whereas CRP and inflammatory cytokines remained unchanged. These results suggest that KBG has insufficient anti-inflammatory or immunomodulating effect but does have a beneficial effect on articular symptoms and a protective effect against endothelial dysfunction in RA patients.

Insulin therapy has a complex relationship with measure of oxidative stress in type 2 diabetes: a case for further study

BACKGROUND

Because pharmacotherapies in type 2 diabetes exert complex effects, we examined the different anti-diabetic strategies, especially the influence of insulin doses, on the activation of oxidative stress, a key player in atherosclerosis, ageing and the risk of cancer.

METHODS

This observational study included 122 persons with type 2 diabetes, 61 treated with oral hypoglycaemic agents alone (group I), 61 treated with a combination of oral hypoglycaemic agents and insulin at either a low dose (<0.40 unit/kg/day, group IIa, n = 30) or high dose (≥0.40 unit/kg/day, group IIb, n = 31) of insulin. Oxidative stress was estimated from 24-h urinary excretion rates of 8-iso-prostaglandin F2α. Haemoglobin A(1c) (%) was also measured to assess overall diabetic control.

RESULTS

The 24-h excretion rates of 8-iso-prostaglandin F2α [median (range) pmol/mmol of creatinine] were much lower in group IIa [68 (32-220)] than in either group I [120 (26-329) p < 0.001] or group IIb [101 (30-289) p = 0.026]. Considering groups IIa and IIb as a whole, a significant and positive relationship (p = 0.021) was observed between insulin dose and 8-iso-prostaglandin F2α. Haemoglobin A(1c) was comparable in the three groups.

CONCLUSIONS

The main benefit of insulin therapy is the restoration and maintenance of near normal glycaemia. However insulin at elevated doses can promote oxidative stress which is thought to be an important mediator of some of the deleterious effects of insulin. Our study shows that the link between insulin action and oxidative stress in type 2 diabetes is complex and warrants further study.

F2-isoprostanes as an indicator and risk factor for coronary heart disease

Coronary heart disease (CHD) is the leading single cause of death in the United States and most Western countries, killing more than 400,000 Americans per year. Although CHD often manifests suddenly as a fatal myocardial infarction, the atherosclerosis that gives rise to the infarction develops gradually and can be markedly slowed or even reversed through pharmacological and lifestyle interventions. These same atherosclerotic processes also drive related vascular diseases such as stroke and peripheral artery disease, and individuals surviving occlusive events often develop additional complications including ischemic cardiomyopathy and heart failure. Therefore, better detection of subclinical atherosclerosis, along with more effective treatments, could significantly reduce the rate of death from CHD and related vascular diseases in the United States. In recent years, oxidation of polyunsaturated fatty acids (PUFAs) in plasma lipoproteins has been postulated to be a critical step in the development of atherosclerosis. If so, then monitoring lipid peroxidation should be a useful indicator of disease risk and progression. This review focuses on the evidence that specific PUFA peroxidation products, the F(2)-isoprostanes, are useful biomarkers that could potentially be utilized as indicators of CHD.

Fenofibrate treatment enhances antioxidant status and attenuates endothelial dysfunction in streptozotocin-induced diabetic rats

Diabetic endothelial dysfunction is accompanied by increased oxidative stress and upregulated proinflammatory and inflammatory mediators in the vasculature. Activation of peroxisome proliferator-activated receptor-alpha (PPAR-α) results in antioxidant and anti-inflammatory effects. This study was designed to investigate the effect of fenofibrate, a PPAR-α activator, on the endothelial dysfunction, oxidative stress, and inflammation in streptozotocin diabetic rats. Diabetic rats received fenofibrate (150 mg kg⁻¹ day⁻¹) for 4 weeks. Fenofibrate treatment restored the impaired endothelium-dependent relaxation and increased basal nitric oxide availability in diabetic aorta, enhanced erythrocyte/liver superoxide dismutase and catalase levels, ameliorated the abnormal serum/aortic thiobarbituric acid reactive substances, and prevented the increased aortic myeloperoxidase without a significant change in serum total cholesterol and triglyceride levels. It did not affect the decreased total homocysteine level and the increased tumor necrosis factor-α level in the serum of diabetic rats. Fenofibrate-induced prevention of the endothelial function seems to be related to its potential antioxidant and antiinflammatory activity.

Effects of fenofibrate on plasma oxidized LDL and 8-isoprostane in a sub-cohort of GOLDN participants

BACKGROUND

Fenofibrate significantly reduces circulating triglyceride (TG) concentrations, particularly in individuals with elevated levels. The purpose of the current study was to determine whether fenofibrate treatment reduces markers of oxidative stress, oxidized low density lipoprotein (ox-LDL) and 8-isoprostane (8-isoP), in a manner similar to TG where those with the highest levels show the greatest reductions.

MATERIALS/METHODS

The concentrations of TG, 8-isoP, and ox-LDL were measured in plasma before and after 3 weeks of fenofibrate treatment (160 mg/d) in a sub-cohort (n=187) of the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) study.

RESULTS

Data were divided into tertiles as determined by pre-treatment values of the respective target. Fenofibrate treatment resulted in significant reductions in TG concentrations by 24.2% (p<0.0001), 41.9% (p < 0.0001), and 46.6% (p < 0.0001) in tertiles 1, 2, and 3, respectively. Significant reductions were also observed in ox-LDL of 7.2% (p=0.0096), 8.5% (p = 0.0019) and 12.1% (p < 0.0001) in tertiles 1, 2, and 3, respectively. Finally, fenofibrate treatment resulted in a 32.7% increase (p=0.0201) in 8-isoP levels in tertile 1, but a significant decrease of 34.4% (p < 0.0001) in tertile 3.

CONCLUSIONS

This study is the largest to date to demonstrate that fenofibrate reduces oxidative stress and the first to show a suppressive effect on 8-isoP levels in individuals with a high oxidative burden following short term (3 wk) drug therapy. Those with the highest baseline levels of ox-LDL and 8-isoP showed the greatest reductions following fenofibrate treatment. Given the role of oxidative stress in atherosclerosis and coronary heart disease, our observations may partially explain the efficacy of fenofibrate in reducing cardiovascular events in select patients.

PPARalpha: an emerging therapeutic target in diabetic microvascular damage

The global pandemic of diabetes mellitus portends an alarming rise in the prevalence of microvascular complications, despite advanced therapies for hyperglycemia, hypertension and dyslipidemia. Peroxisome proliferator-activated receptor alpha (PPARalpha) is expressed in organs affected by diabetic microvascular disease (retina, kidney and nerves), and its expression is regulated specifically in these tissues. Experimental evidence suggests that PPARalpha activation attenuates or inhibits several mediators of vascular damage, including lipotoxicity, inflammation, reactive oxygen species generation, endothelial dysfunction, angiogenesis and thrombosis, and thus might influence intracellular signaling pathways that lead to microvascular complications. PPARalpha has emerged as a novel target to prevent microvascular disease, via both its lipid-related and lipid-unrelated actions. Despite strong experimental evidence of the potential benefits of PPARalpha agonists in the prevention of vascular damage, the evidence from clinical studies in patients with diabetes mellitus remains limited. Promising findings from the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study on microvascular outcomes are countered by elevations in participants' homocysteine and creatinine levels that might potentially attenuate the benefits of PPARalpha activation. This Review focuses on the role of PPARalpha activation in diabetic microvascular disease and highlights the available experimental and clinical evidence from studies of PPARalpha agonists.

Do statins cause myopathy by lowering vitamin E levels?

Statins and other lipid lowering drugs have been repeatedly described to decrease blood levels of minor fat soluble components such as vitamin E (as alpha-tocopherol). Clinical consequences of this secondary state of deficiency have not been described so far, but recent biochemical and molecular evidence on homeostatic and molecular responses to vitamin E deficiency in skeletal muscle cells may suggest the hypothesis presented in this paper of a role as risk factor in the development of statin-associated myopathy. This hypothesis that needs to be further investigated, could suggest the need for precautionary measures during lipid lowering therapy, which include timely diagnosis and active prevention of vitamin E deficiency.

Biomarkers of oxidative stress in heart failure

Oxidative stress is the relative excess of reactive oxygen species (ROS) versus endogenous defense mechanisms. Abundant evidence has demonstrated the role of ROS, along with reactive nitrogen species (RNS), in the pathophysiology of cardiovascular disease, including heart failure. Many biomarkers of oxidative stress have been studied as surrogates of oxidative damage. Recently, markers of impaired nitric oxide signaling have also been identified. Many biomarkers have been associated with prognosis and mortality, and some may even be modified by therapy. However, the clinical utility is limited by less than optimal standardization techniques and the lack of sufficient large-sized, multimarker prospective trials.

In vivo real-time measurement of superoxide anion radical with a novel electrochemical sensor

The dynamics of superoxide anion (O(2)(-)) in vivo remain to be clarified because no appropriate method exists to directly and continuously monitor and evaluate O(2)(-) in vivo. Here, we establish an in vivo method using a novel electrochemical O(2)(-) sensor. O(2)(-) generated is measured as a current and evaluated as a quantified partial value of electricity (Q(part)), which is calculated by integration of the difference between the baseline and the actual reacted current. The accuracy and efficacy of this method were confirmed by dose-dependent O(2)(-) generation in xanthine-xanthine oxidase in vitro in phosphate-buffered saline and human blood. It was then applied to endotoxemic rats in vivo. O(2)(-) current began to increase 1 h after lipopolysaccharide, and Q(part) increased significantly for 6 h in endotoxemic rats, in comparison to sham-treated rats. These values were attenuated by superoxide dismutase. The generation and attenuation of O(2)(-) were indirectly confirmed by plasma lipid peroxidation with malondialdehyde, endothelial injury with soluble intercellular adhesion molecule-1, and microcirculatory dysfunction. This is a novel method for measuring O(2)(-) in vivo and could be used to monitor and treat the pathophysiology caused by excessive O(2)(-) generation in animals and humans.

Effects of propyl gallate on adhesion of polymorphonuclear leukocytes to human endothelial cells induced by tumor necrosis factor alpha

OBJECTIVE

To investigate the effects of Propyl Gallate (PrG) on cellular adhesion between human To investigate the effects of Propyl Gallate (PrG) on cellular adhesion between human umbilical vein endothelial cells (HUVEC) and polymorphonuclear leukocytes (PMN) as well as the expression umbilical vein endothelial cells (HUVEC) and polymorphonuclear leukocytes (PMN) as well as the expression of intercellular adhesion molecule-1 (ICAM-1, CD54) and E-selectin (CD62E) on the VEC surface. of intercellular adhesion molecule-1 (ICAM-1, CD54) and E-selectin (CD62E) on the VEC surface.

METHODS

A human VEC inflammation model was induced by tumor necrosis factor alpha (TNF-alpha). VECs were pre- A human VEC inflammation model was induced by tumor necrosis factor alpha (TNF-alpha). VECs were preincubated with varying concentrations of PrG (0.001-5 mmol/L) or 1 per thousand DMSO (v:v) or 10 mmol/L acetylsalicylic incubated with varying concentrations of PrG (0.001-5 mmol/L) or 1 per thousand DMSO (v:v) or 10 mmol/L acetylsalicylic acid (ASA) for 1 h, and then were stimulated with 10 ng/mL TNF-alpha for 6 h. Rose bengal vital staining method acid (ASA) for 1 h, and then were stimulated with 10 ng/mL TNF-alpha for 6 h. Rose bengal vital staining method was used to measure the adherence rate of PMN to VEC, while flow cytometry was used to determine the was used to measure the adherence rate of PMN to VEC, while flow cytometry was used to determine the expression of CD54 and CD62E on the VEC surface. expression of CD54 and CD62E on the VEC surface.

RESULTS

After 6 h of incubation with TNF-alpha, the adherence After 6 h of incubation with TNF-alpha, the adherence of PMN to HUVECs as well as the percentage of fluorescence-positive cells and mean fluorescence intensity of PMN to HUVECs as well as the percentage of fluorescence-positive cells and mean fluorescence intensity (MFI) of surface CD54 and CD62E in HUVECs increased significantly ( (MFI) of surface CD54 and CD62E in HUVECs increased significantly (P<0.01). Pre-treatment of HUVECs with <0.01). Pre-treatment of HUVECs with PrG (0.1-5 mmol/L) significantly suppressed the adherence of PMN to VECs induced by TNF-alpha (PrG (0.1-5 mmol/L) significantly suppressed the adherence of PMN to VECs induced by TNF-alpha (P<0.05). PrG <0.05). PrG (1-5 mmol/L) inhibited the VEC surface expression of CD62E and CD54 in a dose-dependent way ( (1-5 mmol/L) inhibited the VEC surface expression of CD62E and CD54 in a dose-dependent way (P<0.05). PrG <0.05). PrG at lower concentrations (0.001-0.1 mmol/L) showed no effect on CD54 expression, while it showed a slightly at lower concentrations (0.001-0.1 mmol/L) showed no effect on CD54 expression, while it showed a slightly increasing trend in CD62E expression (increasing trend in CD62E expression (P>0.05). ASA at 10 mmol/L had no obvious effect on the positive rate of >0.05). ASA at 10 mmol/L had no obvious effect on the positive rate of CD62E and CD54. CD62E and CD54.

CONCLUSIONS

High concentrations of PrG (0.1-5 mmol/L) exert its inhibitory effect on cellular High concentrations of PrG (0.1-5 mmol/L) exert its inhibitory effect on cellular adherence of PMN to HUVECs, and its mechanism may be related to inhibiting surface expression of CD54 and adherence of PMN to HUVECs, and its mechanism may be related to inhibiting surface expression of CD54 and CD62E in HUVECs. Its action concentration was lower than that of ASA. CD62E in HUVECs. Its action concentration was lower than that of ASA.

Effects of antioxidant supplementation on insulin sensitivity, endothelial adhesion molecules, and oxidative stress in normal-weight and overweight young adults

The objective of the study was to determine whether short-term antioxidant (AOX) supplementation affects insulin sensitivity, endothelial adhesion molecule levels, and oxidative stress in overweight young adults. A randomized, double-blind, controlled study tested the effects of AOXs on measures of insulin sensitivity (homeostasis model assessment [HOMA]) and quantitative insulin sensitivity check index), endothelial adhesion molecules (soluble intercellular adhesion molecule-1, vascular adhesion molecule, and endothelial-leukocyte adhesion molecule-1), adiponectin, and oxidative stress (lipid hydroperoxides) in overweight and normal-weight individuals (N = 48, 18-30 years). Participants received either AOX (vitamin E, 800 IU; vitamin C, 500 mg; beta-carotene, 10 mg) or placebo for 8 weeks. The HOMA values were initially higher in the overweight subjects and were lowered with AOX by week 8 (15% reduction, P = .02). Adiponectin increased in both AOX groups. Soluble intercellular adhesion molecule-1 and endothelial-leukocyte adhesion molecule-1 decreased in overweight AOX-treated groups by 6% and 13%, respectively (P < .05). Plasma lipid hydroperoxides were reduced by 0.31 and 0.70 nmol/mL in the normal-weight and overweight AOX-treated groups, respectively, by week 8 (P < .05). Antioxidant supplementation moderately lowers HOMA and endothelial adhesion molecule levels in overweight young adults. A potential mechanism to explain this finding is the reduction in oxidative stress by AOX. Long-term studies are needed to determine whether AOXs are effective in suppressing diabetes or vascular activation over time.

The influence of pravastatin and atorvastatin on markers of oxidative stress in hypercholesterolemic humans

OBJECTIVES

The aim of this study was to determine the effects of pravastatin and atorvastatin on markers of oxidative stress in plasma.

BACKGROUND

Hydroxymethylglutaryl coenzyme A reductase inhibitors reduce low-density lipoprotein cholesterol (LDL-C) and cardiovascular risk, but their effects on circulating biomarkers of oxidative stress are not well-defined.

METHODS

Hypercholesterolemic subjects (n = 120, ages 21 to 80 years with LDL-C 130 to 220 mg/dl) were randomized in a double-blind, parallel design to pravastatin 40 mg/day (prava40), atorvastatin 10 mg/day (atorva10), atorvastatin 80 mg/day (atorva80), or placebo. At baseline and 16 weeks, urinary isoprostanes (8, 12-iso-iPF(2 alpha)-VI isoform), plasma lipoprotein-associated phospholipase A2 (Lp-PLA2), Mercodia oxidized LDL (OxLDL) with antibody 4E6, oxidized phospholipids/apolipoprotein B-100 particle (OxPL/apoB) with antibody E06, immunoglobulin (Ig)G/IgM autoantibodies to malondialdehyde (MDA)-LDL, and apolipoprotein B (apoB)-immune complexes (IC) were measured.

RESULTS

After 16 weeks, there were no significant changes in urinary 8, 12-iso-iPF(2 alpha)-VI. The Lp-PLA2 and OxLDL were reduced in statin-treated groups, but after adjusting for apoB, only prava40 led to a reduction in Lp-PLA2 (-15%, p = 0.008) and atorva10 to a decrease in OxLDL (-12.9%, p = 0.01). The OxPL/apoB increased 25.8% (p < 0.01) with prava40 and 20.2% (p < 0.05) with atorva80. There were no changes in MDA-LDL autoantibodies, but significant decreases in IC were noted.

CONCLUSIONS

This study suggests that statin therapy results in variable effects on oxidative stress markers in hypercholesterolemic subjects. Future outcome studies should collectively assess various oxidative markers to define clinical utility.

In vivo markers of oxidative stress and therapeutic interventions

Over the last decade, significant data has accumulated to suggest that biomarkers of oxidative stress accurately reflect the presence of cardiovascular risk factors, the extent of cardiovascular disease (CVD), and cardiovascular outcomes. This cumulative evidence has supported the approval of several of these biomarkers for clinical applications. For example, lipoprotein-associated phospholipase A(2) (Lp-PLA2) and myeloperoxidase (MPO) mass assays are now available to assist clinicians in determining overall cardiovascular risk in asymptomatic patients thought to be at increased risk or in patients with cardiovascular symptoms. However, it is not yet firmly established whether and to what extent these oxidative biomarkers reflect changes in response to therapeutic interventions. This article reviews the latest data on MPO, isoprostanes, oxidized low-density lipoprotein, oxidized phospholipids, and Lp-PLA2 biomarker assays, and it assesses their role in reflecting therapeutic interventions to treat CVD.

Effect of peroxisome proliferator-activated receptor-alpha agonist (bezafibrate) on gastric secretion and gastric cytoprotection in rats

The effect of peroxisome proliferator-activated receptor-alpha (PPAR-alpha) on gastric secretion and gastric cytoprotection was evaluated using five different models of gastric ulcers: acetic acid-induced chronic gastric ulcers, pylorus ligation, ethanol-induced, indomethacin-induced and ischemia-reperfusion-induced gastric ulcers. Bezafibrate, a PPAR-alpha agonist was administered at two different doses of 10 and 100 mg/kg body weight intraperitoneanally. Both doses of bezafibrate showed significant antiulcer effect in ethanol-induced, indomethacin-induced and pylorus ligation-induced gastric ulcers. Bezafibrate increased healing of ulcer in acetic acid-induced chronic gastric ulcer model. Both doses were also effective in preventing gastric lesions induced by ischemia-reperfusion. It was concluded that PPAR-alpha activation increases healing of gastric ulcers and also prevents development of gastric ulcers in rats.

Oxidative biomarkers in the diagnosis and prognosis of cardiovascular disease

Oxidative damage to lipids and proteins is an important component of atherosclerotic cardiovascular disease (CVD). Studies of oxidation-related molecules are helping to define atherosclerotic mechanisms, and measurements of circulating levels of specific oxidant compounds may improve cardiovascular risk assessment. The present article reviews accumulating data of selected oxidative biomarkers that support their role in providing diagnostic and/or prognostic information. For example, plasma levels of the enzyme myeloperoxidase, which generates the strong oxidizing agent hypochlorous acid, have been found to be correlated with risk for myocardial infarction and endothelial dysfunction. Elevated levels of lipoprotein-associated phospholipase A(2) are associated with coronary artery disease (CAD) and stroke. Oxidized phospholipids play an important role in atherosclerosis. Recent studies measuring circulating levels of oxidized phospholipids have suggested a strong association with CAD, plaque disruption, and response to 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor ("statin") therapy. Isoprostanes correlate strongly with cardiovascular risk factors, but their role in risk prediction is less well defined. Future studies are expected to clarify the role of oxidative biomarkers in the diagnosis and prognosis of CVD and to determine their value in specific clinical populations.

Cocoa reduces blood pressure and insulin resistance and improves endothelium-dependent vasodilation in hypertensives

Consumption of flavanol-rich dark chocolate (DC) has been shown to decrease blood pressure (BP) and insulin resistance in healthy subjects, suggesting similar benefits in patients with essential hypertension (EH). Therefore, we tested the effect of DC on 24-hour ambulatory BP, flow-mediated dilation (FMD), and oral glucose tolerance tests (OGTTs) in patients with EH. After a 7-day chocolate-free run-in phase, 20 never-treated, grade I patients with EH (10 males; 43.7+/-7.8 years) were randomized to receive either 100 g per day DC (containing 88 mg flavanols) or 90 g per day flavanol-free white chocolate (WC) in an isocaloric manner for 15 days. After a second 7-day chocolate-free period, patients were crossed over to the other treatment. Noninvasive 24-hour ambulatory BP, FMD, OGTT, serum cholesterol, and markers of vascular inflammation were evaluated at the end of each treatment. The homeostasis model assessment of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), and insulin sensitivity index (ISI) were calculated from OGTT values. Ambulatory BP decreased after DC (24-hour systolic BP -11.9+/-7.7 mm Hg, P<0.0001; 24-hour diastolic BP -8.5+/-5.0 mm Hg, P<0.0001) but not WC. DC but not WC decreased HOMA-IR (P<0.0001), but it improved QUICKI, ISI, and FMD. DC also decreased serum LDL cholesterol (from 3.4+/-0.5 to 3.0+/-0.6 mmol/L; P<0.05). In summary, DC decreased BP and serum LDL cholesterol, improved FMD, and ameliorated insulin sensitivity in hypertensives. These results suggest that, while balancing total calorie intake, flavanols from cocoa products may provide some cardiovascular benefit if included as part of a healthy diet for patients with EH.

Early activation of vascular endothelial cells and platelets in obese children

Obesity in adulthood is combined with vascular endothelial cell and platelet activation. In this study we evaluated whether or not such activation is already present in obese children. Forty obese (10.3 +/- 2.5 yr) and 40 nonobese (10.3 +/- 2.3 yr) children were studied. Circulating levels of soluble (s) intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin, as indices of vascular endothelial cell activation, were assessed in both groups. Plasma concentrations of sP-selectin and sCD40 ligand, as indices of platelet activation, were also measured. Circulating levels of highly sensitive C-reactive protein (hs-CRP) and the lipid peroxidation product 8-iso-prostaglandin (PG)F(2alpha) were evaluated because of their ability to promote vascular endothelial cell and platelet activation. Circulating levels of all of the assessed markers were higher in obese than in nonobese children (sICAM-1, +38.8 +/- 13.3%; sVCAM-1, +26.5 +/- 13.7%; sE-selectin, +31.3 +/- 17.3%; sP-selectin, +31.7 +/- 16.9%; sCD40 ligand, +36.9 +/- 22.1%; total 8-iso-PGF(2alpha), +24.0 +/- 20.2%; hs-CRP, +76.6 +/- 12.9%; P < 0.0001). Significant correlations (P < 0.004) between plasma total 8-iso-PGF(2alpha) levels and circulating sICAM-1 (r = 0.485), sVCAM-1 (r = 0.506), sP-selectin (r = 0.449), sCD40 ligand (r = 0.498), and hs-CRP (r = 0.520) concentrations were found in obese children. In conclusion, an early activation of vascular endothelial cells and platelets was present in obese children. Increased lipid peroxidation was also present in these children and likely contributed to the observed proinflammatory phenotype.

Endothelial function and dysfunction. Part I: Methodological issues for assessment in the different vascular beds: a statement by the Working Group on Endothelin and Endothelial Factors of the European Society of Hypertension

An enormous number of studies in the last two decades have been devoted to investigating the role of the endothelium in cardiovascular diseases. Nonetheless, the optimal methodology for investigating the multifaceted aspects of endothelial dysfunction is still under debate. Biochemical markers, molecular genetic tests and invasive and non-invasive tools with and without pharmacological and physiological stimuli have been introduced. Furthermore newer pharmacological tools have been proposed. However, the application of these methodologies should fulfil a number of requirements in order to provide conclusive answers in this area of research. Thus, the most relevant methodological issues in the research on endothelial function and dysfunction are summarized in this paper.

Factors regulating isoprostane formation in vivo

Discovery of the F2-isoprostanes, a group of prostaglandin F2-like compounds biosynthesized from arachidonic acid nonenzymatically, has uncovered a new and novel facet of free radical biology. Some of these compounds are bioactive and thus may mediate adverse effects associated with oxidant stress. F2-Isoprostanes have also been shown to be reliable biomarkers of lipid peroxidation. Factors influencing their formation and metabolism have been studied to some extent, although much remains to be determined. The purpose of this review is to summarize our current knowledge of conditions that modulate endogenous generation of these compounds. Isoprostanes have a wide daily variation in secretion in humans. Although normal levels can be defined, these compounds are found in increased concentrations in various pathophysiological states, including ischemia-reperfusion injury, atherosclerosis, and diabetes, and in experimental conditions of oxidative stress and inflammation. Alterations in isoprostane biosynthesis, secretion, and excretion in normal physiology and in pathophysiological states are due to the various types of endogenous and exogenous regulatory mechanisms that control the availability of precursors required for isoprostane synthesis, such as dietary and tissue arachidonic acid content, oxygen concentration, and the generation of various free radical species. Selected aspects of issues related to isoprostane formation and metabolism in vivo will be examined herein.

Vitamin E Modulation of Cardiovascular Disease

Endothelium in the vascular system is an important modulator of vasomotor tone and coagulation, and it plays a crucial role in the inhibition of adhesion and activation of platelets and leukocytes. Evidence indicates that dietary antioxidants may modulate these endothelium-dependent vascular functions through several mechanisms and may contribute to the prevention of vascular diseases such as atherosclerosis. Several cell cultures as well as animal and human clinical and observational studies have tested the efficacy of vitamin E on vascular function and the prevention of atherosclerosis. Our cell culture studies have indicated that vitamin E (alpha-tocopherol) inhibits the activation of endothelial cells stimulated by high levels of low-density lipoprotein cholesterol and pro-inflammatory cytokines. This inhibition is associated with the suppression of chemokines, the expression of cell surface adhesion molecules, and the adhesion of leukocytes to endothelial cells, all of which contribute to the development of lesions in the arterial wall. The molecular mechanisms by which alpha-tocopherol and other tocopherols modulate endothelial cells and smooth muscle functions have been delineated. We, and others, have also demonstrated a positive effect of dietary vitamin E on endothelium and vascular function in animal models of atherosclerosis. Several human clinical trials have also shown an improvement in the surrogate markers of atherosclerosis and vascular function by vitamin E supplementation. However, these findings have been contradicted by several vitamin E supplementation trials for the prevention of secondary cardiovascular events showing null effect. Intervention at a relatively late stage of disease and the single use of vitamin E rather than in combination with other antioxidants might have contributed to these contradictory findings. Evidence from cell cultures, as well as animal and human clinical and observational studies, strongly supports the contribution of dietary vitamin E to the maintenance of vascular function and health, in particular when it is used in combination with other dietary antioxidants, which are found in fruits, vegetables, and nuts.