The effects of lipid-lowering therapy on low-density lipoprotein auto-antibodies: relationship with low-density lipoprotein oxidation and plasma total antioxidant status

Behavior of the total antioxidant status in a group of subjects with metabolic syndrome

AIMS

Our purpose was to examine the total antioxidant status (TAS) in subjects with metabolic syndrome (MS) subdivided according to the presence or not of diabetes mellitus.

METHODS

We enrolled 106 subjects (45 women, 61 men) with MS subsequently subdivided in diabetics (14 women, 29 men) and nondiabetics (31 women, 29 men). TAS was obtained using an Assay kit which relies on the ability of plasma antioxidant substances to inhibit the oxidation of 2,2'-azino-bis(3-ethylbenzthiazoline sulfonic acid) to the radical ABTS·+.

RESULTS

In the group of MS subjects a significant decrease in TAS (p<0.05) in comparison with normal controls was evident. This difference was present between normal subjects and nondiabetic subjects with MS (p<0.001) but not between normal and diabetic subjects with MS. Examining the linear regression among TAS, age, anthropometric profile, blood pressure values and glycometabolic pattern, conflicting data were found.

CONCLUSIONS

Although we know that TAS includes several enzymatic and non enzymatic antioxidants, we retain that the difference observed in the two subgroups of subjects with MS must be looked in particular into two pathophysiological aspects regarding bilirubin and uric acid.

Implication of low HDL-c levels in patients with average LDL-c levels: a focus on oxidized LDL, large HDL subpopulation, and adiponectin

To evaluate the impact of low levels of high density lipoprotein cholesterol (HDL-c) on patients with LDL-c average levels, focusing on oxidative, lipidic, and inflammatory profiles. Patients with cardiovascular risk factors (n = 169) and control subjects (n = 73) were divided into 2 subgroups, one of normal HDL-c and the other of low HDL-c levels. The following data was analyzed: BP, BMI, waist circumference and serum glucose Total-c, TGs, LDL-c, oxidized LDL, total HDL-c and subpopulations (small, intermediate, and large), paraoxonase-1 (PON1) activity, hsCRP, uric acid, TNF-α, adiponectin, VEGF, and iCAM1. In the control subgroup with low HDL-c levels, significantly higher values of BP and TGs and lower values of PON1 activity and adiponectin were found, versus control normal HDL-c subgroup. However, differences in patients' subgroups were clearly more pronounced. Indeed, low HDL-c subgroup presented increased HbA1c, TGs, non-HDL-c, Ox-LDL, hsCRP, VEGF, and small HDL-c and reduced adiponectin and large HDL. In addition, Ox-LDL, large-HDL-c, and adiponectin presented interesting correlations with classical and nonclassical markers, mainly in the normal HDL-c patients' subgroup. In conclusion, despite LDL-c average levels, low HDL-c concentrations seem to be associated with a poor cardiometabolic profile in a population with cardiovascular risk factors, which is better evidenced by traditional and nontraditional CV biomarkers, including Ox-LDL, large HDL-c, and adiponectin.

The effects of atorvastatin and rosuvastatin on oxidative stress in diabetic patients

AIM

Diabetes is associated with abnormalities in lipid profile and increased oxidative stress. Statins are preferred agents in diabetic patients due to their antioxidant and LDL-C lowering effects. This study is designed to compare the effects of atorvastatin and rosuvastatin on low density lipoprotein cholesterol (LDL-C), lipid hydroperoxide (LOOH), total oxidant status (TOS) and total antioxidant capacity (TAC) in diabetic patients with hyperlipidemia.

MATERIALS AND METHODS

Sixty two patients who have type 2 diabetes mellitus with serum LDL levels more than 100mg/dL were randomly assigned to receive atorvastatin 20mg (n=31) or rosuvastatin 10mg (n=31). Blood tests were performed at the beginning of the study and after three months.

RESULTS

There were no statistically significant differences in the pre- and after treatment levels of the LDL-C between groups. TAC values were increased in both groups and statistically significant in the former group (p=0.007). There was no difference between the change percentages ((after treatment TAC-pretreatment TAC)/pretreatment level) of TAC between two treatment groups. The effects of two drugs on the other oxidative parameters were not significantly different.

CONCLUSION

Both atorvastatin and rosuvastatin may be helpful in reducing increased oxidative stress in diabetic patients with hyperlipidemia.

Effect of atorvastatin therapy on oxidant-antioxidant status and atherosclerotic plaque formation

Background:

The aim of this study was to determine the oxidant–antioxidant status and lipid peroxidation products, as well as paraoxonase and atherosclerotic plaque formation, in a hypercholesterolemic atherosclerosis rabbit model to investigate the effects of atorvastatin in the atherosclerotic process.

Methods:

Forty male New Zealand rabbits were divided into four groups, ie, a control group receiving standard pellets, a group receiving atorvastatin therapy, a hypercholesterolemic group receiving an atherogenic diet, and a group receiving both an atherogenic diet and atorvastatin.

Results:

The atherogenic diet increased the levels of low-density lipoprotein (LDL) thiobarbituric acid reactive substances (1.84 vs 3.79 nmol/mg protein) and LDL-conjugated diene (147 vs 318 μmol/mg protein) after induction of oxidation by Cu²⁺, despite an increase of superoxide dismutase activity. Treatment with atorvastatin limited LDL oxidation significantly (LDL thiobarbituric acid reactive substances 2.19 nmol/mg protein, LDL-conjugated diene 222 μmol/mg protein). Paraoxonase, which prevents LDL oxidation and inactivates LDL-derived oxidized phospholipids, showed a pronounced decrease in the group receiving the atherogenic diet (110 U/L to 28 U/L), and atorvastatin treatment increased paraoxonase activity. Histological examination of arcus aorta tissues from the hypercholesterolemic group showed abundant plaque formation surrounding and obstructing the lumen, whereas treatment with atorvastatin prevented or limited plaque formation, keeping the plaque thin and localized.

Conclusion:

Atorvastatin has dramatic antiatherosclerotic effects, part of which seems to be due to the antioxidant features of the parent drug and/or its metabolites, favoring inhibition of LDL oxidation.

Caveolae and caveolin-1 mediate endocytosis and transcytosis of oxidized low density lipoprotein in endothelial cells

AIM

To explore the mechanisms involved in ox-LDL transcytosis across endothelial cells and the role of caveolae in this process.

METHODS

An in vitro model was established to investigate the passage of oxidized low density lipoprotein (ox-LDL) through a tight monolayer of human umbilical vein endothelial cells (HUVEC) cultured on a collagen-coated filter. Passage of DiI-labeled ox-LDL through the monolayer was measured using a fluorescence spectrophotometer. The uptake and efflux of ox-LDL by HUVEC were determined using fluorescence microscopy and HPLC.

RESULTS

Caveolae inhibitors - carrageenan (250 μg/mL), filipin (5 μg/mL), and nocodazole (33 μmol/L)-decreased the transport of ox-LDL across the monolayer by 48.9%, 72.4%, and 79.8% as compared to the control group. In addition, they effectively decreased ox-LDL uptake and inhibited the efflux of ox-LDL. Caveolin-1 and LOX-1 were up-regulated by ox-LDL in a time-dependent manner and decreased gradually after depletion of ox-LDL (P<0.05). After treatment HUVEC with ox-LDL and silencing caveolin-1, NF-κB translocation to the nucleus was blocked and LOX-1 expression decreased (P<0.05).

CONCLUSION

Caveolae can be a carrier for ox-LDL and may be involved in the uptake and transcytosis of ox-LDL by HUVEC.

Functional food ingredients as adjunctive therapies to pharmacotherapy for treating disorders of metabolic syndrome

Abstract Information regarding the use of functional foods and nutraceuticals (FFN) in combating disease is rarely communicated to health care practitioners as medicinal strategies for patients. Metabolic syndrome (MetS) is an ideal paradigm for demonstrating the therapeutic properties of FFN. Encompassing multiple etiologies, including atherogenic dyslipidemia, insulin resistance, and hypertension, MetS affects over a third of American adults. However, as disease-related risk factors accumulate over time, guidelines for treating disorders of MetS progressively de-emphasize the use of FFN. Using marine omega-3 fatty acids, plant sterols, fiber, and tomato extract as examples, the purpose of this review is to endorse FFN as long-term adjunctive therapies to pharmaceutical treatment for disorders and risk factors for MetS. An additional goal is to compare physiological and molecular targets of FFN against corresponding prescription medications. Results reveal that FFN are viable treatment strategies for disorders of MetS, complementing pharmacological interventions by targeting and improving the biological processes that foster the development of disease. Thus, efficacious FFN therapies should be emphasized throughout all stages of treatment as adjuncts to pharmacotherapy for disorders of MetS. Accordingly, new developments in FFN research must be implemented into clinical guidelines with the prospect of improving disease prognoses as accessories to prescription medications.

A higher level of IgM anti-oxidized LDL antibodies is associated with a lower severity of coronary atherosclerosis in patients on statins

BACKGROUND

Several studies show the association between anti-oxidized LDL antibodies and atherosclerosis. A certain association also seems to exist between the levels of these antibodies and treatment with statins. However, the clinical importance of these autoantibodies is still under discussion. The aim of this study was to determine whether levels of anti-oxidized LDL antibodies are associated with the presence of multivessel coronary artery disease according to whether statins were or were not being taken.

METHODS AND RESULTS

The study included 236 patients who underwent invasive coronary angiography with quantification of coronary atherosclerotic lesions to determine the presence of multivessel coronary artery disease. Measurements were made of IgG and IgM anti-oxidized LDL antibodies. In the group of patients who were taking statins, the percentage of patients with IgM anti-oxidized LDL antibodies below 50th percentile was significantly higher in those with multivessel coronary artery disease (57.4% vs. 37.5%, P<0.05). A logistic regression model in the patients taking statins showed that the variable significantly associated with the presence of multivessel coronary artery disease was the level of IgM anti-oxidized LDL antibodies.

CONCLUSIONS

The severity of multivessel coronary artery disease was inversely related with the levels of IgM anti-oxidized LDL antibodies, especially in the patients on statins.

Acute fish oil and soy isoflavone supplementation increase postprandial serum (n-3) polyunsaturated fatty acids and isoflavones but do not affect triacylglycerols or biomarkers of oxidative stress in overweight and obese hypertriglyceridemic men

Chronic consumption of fish and fish oil high in (n-3) PUFA reduces triacylglycerols (TG) but may increase oxidative stress, whereas consumption of soy isoflavones may reduce oxidative stress. Elevated serum TG and oxidative stress are considered cardiovascular disease (CVD) risk factors, but the effects of acute (n-3) PUFA and soy isoflavones on these CVD risk factors are unknown. The purpose of the study was to determine the effects of acutely supplementing a high-fat, high-fructose meal with fish oil and isoflavone placebo (FO) and fish oil placebo and soy isoflavones (ISO). In a randomized, double-blind, placebo-controlled, crossover study, 10 overweight or obese men consumed a high-fat, high-fructose meal with 4 dietary supplement combinations: fish oil placebo and isoflavone placebo (placebo); fish oil and isoflavone placebo (FO); fish oil placebo and isoflavones (ISO); and fish oil and isoflavones (FO + ISO). Serum collected at baseline and at 2, 4, and 6 h postprandially was analyzed for fatty acids, isoflavones, TG, and oxidative stress biomarkers (lipid hydroperoxides, oxidized-LDL, total antioxidant status). FO significantly increased serum (n-3) PUFA and ISO increased serum isoflavones. The study meal significantly increased serum total fatty acids and TG without affecting oxidative stress biomarkers. Serum TG and oxidative stress biomarkers did not differ between treatments. The FO and ISO were bioavailable but did not attenuate the postprandial rise in serum TG. Neither the study meal nor the FO or ISO induced significant changes in oxidative stress biomarkers. The current study adds to a limited literature on the acute effects of FO and ISO interventions on postprandial biomarkers of CVD risk.

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.

Beneficial effects of diclofenac therapy on serum lipids, oxidized low-density lipoprotein and antioxidant defenses in rats

To study the effects of diclofenac, a nonselective nonsteroidal anti-inflammatory drug (NSAID), on lipid profile, oxidized low-density-lipoprotein (Ox-LDL), serum antioxidant defenses and markers of oxidative stress, male Wistar rats were divided into two groups (n=10): (C) receiving intramuscularly a single daily dose of saline (NaCl 0.9%), and (AI) receiving intramuscularly a single daily dose of 10 mg/kg diclofenac sodium (C14H10Cl2NNaO2). After 28 days diclofenac-treated rats had lower Ox-LDL, apoprotein B (apo-B), apo-B/LDL-cholesterol and lipid hydroperoxide than C. Total antioxidant substances and superoxide dismutase were increased in diclofenac-treated rats, while no significant changes were observed in catalase, glutathione peroxidase and nitric oxide. A perincubation test done to examine the possibility of mechanism-based activation showed that diclofenac had no effect on maximal superoxide dismutase velocity, but significantly reduced the Michaelis-Menten (KM) constant, indicating that diclofenac induced SOD activation increasing substrate linkage affinity to the enzyme-catalytic site. In conclusion, diclofenac had beneficial effects decreasing Ox-LDL and improving antioxidant defense. It appears that the application of this agent may be feasible and beneficial for serum antioxidant protection, which certainly would bring new insights on dyslipidemia control.

Oxidative stress in young subjects with acute myocardial infarction: evaluation at the initial stage and after 12 months

In 105 subjects (97 men and 8 women) aged <46 years (mean age 39.6 +/- 5.5 years), with recent acute myocardial infarction (T1), thiobarbituric acid reactive substances and total antioxidant status were determined; NO production was evaluated by measuring the nitrite and nitrate (NOx) concentration. The patients with acute myocardial infarction were subdivided according to the main risk factors, number of risk factors, and extent of coronary lesions. The evaluation was repeated after 12 months (T2). In these subjects, thiobarbituric acid reactive substances and NOx were significantly increased and total antioxidant status was significantly decreased at T1. In single risk factor, only NO metabolites were significantly lower in acute myocardial infarction subjects who smoke than in subjects who do not. Subdividing the subjects according to the number of risk factors and number of stenosed coronary vessels, there were no significant differences between the subgroups. At T2, thiobarbituric acid reactive substances and NOx were decreased and total antioxidant status was increased, but all parameters were still altered.

Reduction of oxidative stress and modulation of autoantibodies against modified low-density lipoprotein after rosuvastatin therapy

AIMS

To examine the effect of 24 weeks' rosuvastatin treatment on oxidative stress and changes in immune response to oxidized low-density lipoprotein (LDL).

METHODS

This was an open-label study of patients in Austria receiving 10 or 40 mg rosuvastatin daily alternately during 12 and 24 weeks. Circulating concentrations of antibodies to malondialdehyde-oxidized LDL (MDA-LDL), both IgG and IgM type, to copper-oxidized LDL (Cu-OxLDL-IgG), concentrations of oxidized LDL complexed to IgG (OxLDL-IC) and markers of oxidative stress and systemic inflammation in subjects with plasma LDL cholesterol concentrations between 130 mg dl-1 and 250 mg dl-1 and triglycerides

RESULTS

During statin therapy, plasma endogenous peroxides (POX-ACT) concentrations and peroxidase activity were significantly decreased, associated with a modest increase in total antioxidant capacity (TAC). Antibody titres to MDA-LDL-IgM, Cu-OxLDL-IgG and OxLDL-IC decreased, whereas MDA-LDL-IgG concentrations were increased after therapy. These changes were dose- and LDL-independent. POX-ACT concentrations were significantly positively correlated with inflammation markers before and after therapy and inversely with high-density lipoprotein-cholesterol concentrations after therapy.

CONCLUSION

This study provides in vivo evidence that rosuvastatin significantly reduces oxidative stress and has immunomodulatory properties in a dose- and LDL-independent manner.

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Key Words

• autoantibodies
• oxidative stress
• oxidatively modified low-density lipoprotein
• rosuvastatin

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MESH Headings

• Antioxidants/metabolism
• Autoantibodies/immunology
• Biomarkers/blood
• Copper/metabolism
• Dose-Response Relationship, Drug
• Female
• Fluorobenzenes/therapeutic use
• Humans
• Hydroxymethylglutaryl-CoA Reductase Inhibitors/therapeutic use
• Immunoglobulin G/immunology
• Immunoglobulin M/immunology
• Lipoproteins, LDL/metabolism
• Male
• Malondialdehyde/metabolism
• Middle Aged
• Oxidation-Reduction
• Oxidative Stress/drug effects
• Peroxidase/metabolism
• Peroxides/blood
• Pyrimidines/therapeutic use
• Rosuvastatin Calcium
• Sulfonamides/therapeutic use

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Grants Collapse

Affiliation(s)

Ulrike Resch Medical University of Vienna, Wilhelm Auerswald Atherosclerosis Research Group, Vienna, Austria.
Franz Tatzber
Alexandra Budinsky
Helmut Sinzinger

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Antibodies to oxidized LDL in atherosclerosis development--clinical and animal studies

Atherosclerotic lesions represent the principal cause of death in western industrialized countries. Immune mechanisms have been suggested to play a key role in the development of atherosclerosis. Several lines of evidence support that oxidized LDL (oxLDL) may be a key antigen in atherosclerosis. Antibodies to oxLDL have been found in human and rabbit plasma and in atherosclerotic lesions. So far, it has not been well established if the immune response is predominantly pro- or antiatherogenic. During the last decade, numerous studies have been performed investigating the relationship between circulating antibodies in plasma in relation to endothelial dysfunction, subclinical atherosclerosis and cardiovascular events in different patient categories. Taken together, these studies have shown diverging results. However, most studies have shown that elevated IgG titers to oxLDL are related to atherosclerotic disease. Even if fewer studies have investigated IgM titers, most studies seem to show an inverse relationship between IgM titers and atherosclerotic disease. In animal studies, it has been shown that immunization with oxLDL induces antibody formation (both IgG and IgM) and protects against atherosclerosis development. Furthermore, it has also been shown that immunization with Streptococcus pneumoniae induce an IgM response, which is associated with decreased atherosclerosis development, and plasma from these mice also has the ability to block uptake of oxLDL to macrophages. To conclude, antibodies to oxLDL in clinical cardiovascular disease show diverging results, while animal studies suggest that immunization may have a beneficial role in atherosclerosis development. Prospective and intervention studies, as well as mechanistic studies are clearly needed to elucidate the possible causal role of antibodies to oxLDL in man.

Dietary lipids in the aetiology of Alzheimer's disease: implications for therapy

Amyloid plaques and neurofibrillary tangles are the neuropathological hallmarks of Alzheimer's disease (AD), but no conclusive evidence has emerged showing that these hallmarks are the cause and not a product of the disease. Many studies have implicated oxidation and inflammation in the AD process, and there is growing evidence that abnormalities of lipid metabolism also play a role. Using epidemiology to elucidate risk factors and histological changes to suggest possible mechanisms, the hypothesis is advanced that dietary lipids are the principal risk factor for the development of late-onset sporadic AD. The degree of saturation of fatty acids and the position of the first double bond in essential fatty acids are the most critical factors determining the effect of dietary fats on the risk of AD, with unsaturated fats and n-3 double bonds conferring protection and an overabundance of saturated fats or n-6 double bonds increasing the risk. The interaction of dietary lipids and apolipoprotein E isoforms may determine the risk and rate of sustained autoperoxidation within cellular membranes and the efficacy of membrane repair. Interventions involving dietary lipids and lipid metabolism show great promise in slowing or possibly averting the development of AD, including dietary changes, cholesterol-modifying agents and antioxidants.

Antibodies to oxidized low-density lipoprotein in patients following coronary artery revascularization

BACKGROUND

Measurement of antibodies to oxidized low-density lipoprotein (AB-oxLDL) has been proposed as a way of identifying individuals at risk for cardiovascular disease beyond the determination of LDL cholesterol (LDL-c) alone. While this hypothesis is appealing, evidence that AB-oxLDL is a risk factor independent of LDL-c levels remains to be established.

METHODS AND RESULTS

We conducted a cross-sectional study of 158 hypercholesterolemic adults who underwent coronary revascularization. Patients were randomized in a clinical trial to a nurse case management (NURS) or an enhanced usual care (EUC) group. The goal in the NURS group was to achieve an LDL-c <85 mg/dl with pharmacotherapy and lifestyle advice. Six months after revascularization, serum and urine were collected to determine lipids, AB-oxLDL, urinary isoprostanes (an in-vivo marker of oxidative damage), oxygen-radical-absorbing capacity (ORAC) of serum, serum carotenoids, alpha-tocopherol and C-reactive protein (CRP). After 6 months of intervention, the NURS group had a mean (+/-SD) LDL-c of 84 (18) mg/dl compared with 105 (25) mg/dl in the EUC group (P < 0.001). In addition, AB-oxLDL was lower (median +/- 95% confidence interval, -202 milliunits (mU)/ml, -372 to -32, P = 0.02) in the NURS group (488 mU/ml, 399, 588) than in the EUC group (690 mU/ml, 544, 847). The difference in AB-oxLDL between groups persisted after adjustment for LDL-c (-316 mU/ml, -519 to -112, P = 0.005). Further adjustment for ORAC and alpha-tocopherol did not diminish the group effect. The groups did not differ significantly in serum antioxidants, urinary isoprostane excretion or CRP. In additional analyses, change in LDL-c from baseline was not associated with AB-oxLDL at 6 months.

CONCLUSIONS

Our results demonstrate lower AB-oxLDL in patients who achieve greater lipid reduction. However, AB-oxLDL appears to be independent of achieved LDL-c, ORAC levels or serum antioxidant levels. These results support the hypothesis that AB-oxLDL is independent of LDL-c level. Further prospective studies are needed to determine the prognostic value of AB-oxLDL.