Atherogenic Lipoproteins for the Statin Residual Cardiovascular Disease Risk

Randomized controlled trials (RCTs) show that decreases in low-density lipoprotein cholesterol (LDL-C) by the use of statins cause a significant reduction in the development of cardiovascular disease (CVD). However, one of our previous studies showed that, among eight RCTs that investigated the effect of statins vs. a placebo on CVD development, 56–79% of patients had residual CVD risk after the trials. In three RCTs that investigated the effect of a high dose vs. a usual dose of statins on CVD development, 78–87% of patients in the high-dose statin arms still had residual CVD risk. The risk of CVD development remains even when statins are used to strongly reduce LDL-C, and this type of risk is now regarded as statin residual CVD risk. Our study shows that elevated triglyceride (TG) levels, reduced high-density lipoprotein cholesterol (HDL-C), and the existence of obesity/insulin resistance and diabetes may be important metabolic factors that determine statin residual CVD risk. Here, we discuss atherogenic lipoproteins that were not investigated in such RCTs, such as lipoprotein (a) (Lp(a)), remnant lipoproteins, malondialdehyde-modified LDL (MDA-LDL), and small-dense LDL (Sd-LDL). Lp(a) is under strong genetic control by apolipoprotein (a), which is an LPA gene locus. Variations in the LPA gene account for 91% of the variability in the plasma concentration of Lp(a). A meta-analysis showed that genetic variations at the LPA locus are associated with CVD events during statin therapy, independent of the extent of LDL lowering, providing support for exploring strategies targeting circulating concentrations of Lp(a) to reduce CVD events in patients receiving statins. Remnant lipoproteins and small-dense LDL are highly associated with high TG levels, low HDL-C, and obesity/insulin resistance. MDA-LDL is a representative form of oxidized LDL and plays important roles in the formation and development of the primary lesions of atherosclerosis. MDA-LDL levels were higher in CVD patients and diabetic patients than in the control subjects. Furthermore, we demonstrated the atherogenic properties of such lipoproteins and their association with CVD as well as therapeutic approaches.

Serum Malondialdehyde-Modified Low-Density Lipoprotein Is a Risk Factor for Central Arterial Stiffness in Maintenance Hemodialysis Patients

Circulating malondialdehyde-modified low-density lipoprotein (MDA-LDL) acts as a marker of oxidative stress and is associated with atherosclerotic cardiovascular disease. The relationship between serum MDA-LDL levels and aortic stiffness (AS) in patients with hemodialysis (HD) was evaluated. There were 155 HD patients enrolled in this study. Carotid-femoral pulse wave velocity (cfPWV) was measured by a validated tonometry system. Patients with cfPWV >10 m/s were used to define the AS group, while those with values of ≤10 m/s were regarded as the control group. Serum MDA-LDL levels were measured using a commercial enzyme-linked immunosorbent assay. Sixty-eight patients (43.9%) who were defined as AS sufferers, and were older, had a higher percentage of diabetes and hypertension and higher systolic blood pressure and serum MDA-LDL level compared to subjects in the control group. After adjusting for factors significantly associated with AS by multivariable logistic regression analysis, it was revealed that serum MDA-LDL levels, diabetes, and hypertension were independent predictors of AS in HD patients. Multivariable forward stepwise linear regression analysis also showed that a logarithmically transformed MDA-LDL level was significantly correlated with cfPWV values in HD patients. In HD patients, a high serum MDA-LDL level was positively associated with cfPWV values and was a significant predictor of the development of high AS.

[Pleiotropic effects of ezetimibe]

The article discusses in detail the question of the additional positive effects of ezetimibe in addition to direct hypolipidemic action. The data of experimental and clinical studies in which the effect of ezetimibe on carbohydrate metabolism, inflammation, endothelial dysfunction, and liver is studied. The article also discusses the results of clinical studies that examined the effect of ezetimibe on atherosclerotic plaque.

Progress and perspectives in plant sterol and plant stanol research

Current evidence indicates that foods with added plant sterols or stanols can lower serum levels of low-density lipoprotein cholesterol. This review summarizes the recent findings and deliberations of 31 experts in the field who participated in a scientific meeting in Winnipeg, Canada, on the health effects of plant sterols and stanols. Participants discussed issues including, but not limited to, the health benefits of plant sterols and stanols beyond cholesterol lowering, the role of plant sterols and stanols as adjuncts to diet and drugs, and the challenges involved in measuring plant sterols and stanols in biological samples. Variations in interindividual responses to plant sterols and stanols, as well as the personalization of lipid-lowering therapies, were addressed. Finally, the clinical aspects and treatment of sitosterolemia were reviewed. Although plant sterols and stanols continue to offer an efficacious and convenient dietary approach to cholesterol management, long-term clinical trials investigating the endpoints of cardiovascular disease are still lacking.

Effect of ezetimibe on plasma adipokines: a systematic review and meta-analysis

AIMS

Statins are known to influence the status of adipokines, which play a key role in the pathophysiology of cardiometabolic diseases. As the effect of ezetimibe as an add-on to statin therapy on the impact of statins on plasma adipokines levels is currently unclear, the aim of the present study was to investigate this through a meta-analysis of controlled trials.

METHODS

A systematic review was performed, followed by a bibliographic search in PubMed, Medline, SCOPUS, Web of Science and Google Scholar databases. Quantitative data synthesis was performed using a fixed- or random-effects model (based on the level of interstudy heterogeneity) and the generic inverse variance weighting method. Effect sizes were expressed as standardized mean difference (SMD) and 95% confidence interval (CI).

RESULTS

Meta-analysis of 23 controlled trials did not suggest any significant effect of adding ezetimibe on top of statin therapy on plasma concentrations of adiponectin (SMD 0.34, 95% CI -0.28, 0.96; P = 0.288), leptin (SMD -0.75, 95% CI: -2.35, 0.85; P = 0.360), plasminogen activator inhibitor 1 (SMD -1.06, 95% CI: -2.81, 0.69; P = 0.236) and interleukin 6 (SMD 0.30, 95% CI: -0.08, 0.67; P = 0.124). However, significantly greater reductions in plasma concentrations of tumour necrosis factor α (TNF-α) (SMD -0.48, 95% CI -0.87, -0.08; P = 0.018) were achieved with ezetimibe/statin combination therapy.

CONCLUSIONS

The results suggested that ezetimibe add-on to statin therapy is associated with an enhanced TNF-α-lowering effect compared with statin monotherapy. Owing to the emerging role of TNF-α in the pathogenesis of metabolic disorders, further investigations are required to unveil the translational relevance of this TNF-α-lowering effect.

Coadministration of ezetimibe with pegylated interferon plus ribavirin could improve early virological response in chronic hepatitis C obese Egyptian patients

BACKGROUND

Ezetimibe has been reported to inhibit viral entry and to reduce BMI and has been proposed as a novel therapeutic agent for chronic hepatitis C (CHC), potentiating the effects of pegylated interferon and ribavirin (peg-IFN/RBV).

OBJECTIVE

The aim of the study was to assess the effects of ezetimibe coadministration with peg-IFN/RBV combination on the early virological response (EVR) rates in nonobese and obese patients with CHC genotype 4 (CHC-4).

PATIENTS AND METHODS

A total of 144 CHC-4 patients were divided into two groups; group 1 included nonobese patients (n=76) and group 2 included obese patients (n=68). Each group was further subclassified into equal control and treated groups. The control groups received peg-IFN/RBV combination for 24 weeks, and the treated groups received peg-IFN/RBV plus ezetimibe for 12 weeks and then only peg-IFN/RBV for the remaining 12 weeks.

RESULTS

The study revealed that EVR significantly improved in the obese patients (85.3 vs. 64.7% in the treated and control groups, respectively, at P<0.05) without any significant improvement in the nonobese patients. Biochemical responses (defined as normalization of alanine aminotransferase at week 12) were markedly improved in the treated groups in both the nonobese and obese groups compared with their respective controls.

CONCLUSION

The addition of ezetimibe to peg-IFN/RBV combination significantly improves EVR rates in obese patients compared with nonobese patients, and remarkably improves the biochemical responses in both obese and nonobese patients with CHC-4. This may shed light on a new strategy for the treatment of CHC, particularly in obese Egyptian patients.

Cardiovascular protection by ezetimibe and influence on oxidative stress in mice exposed to intermittent hypoxia

Ezetimibe is as an inhibitor of NPC1L1 protein, which has a key role in cholesterol absorption. The aim of this study was to evaluate the influence of ezetimibe on the plasma lipid profile, atherosclerotic lesions, and cardiomyocyte ultrastructure in an animal model of atherosclerosis with intermittent hypoxia. Apolipoprotein E-knockout mice received a high-fat diet for 30 days. Then animals were exposed to intermittent hypoxia for 10 days or were maintained under normoxic conditions. In the ezetimibe group, ezetimibe (5 mg/kg/day) was added to the diet. Under normoxic conditions, the total cholesterol level was significantly lower in the ezetimibe group (63.6±6.6 mg/dl) than in the control group (116.3±16.9 mg/dl, P<0.001). Intermittent hypoxia accelerated atherosclerosis associated with increased superoxide production, which also caused degeneration of cardiomyocytes, mitochondrial abnormalities, and interstitial fibrosis. Compared with the control group, the ezetimibe group showed significantly less advanced atherosclerotic lesions and lower superoxide production in the thoracic aorta, as well as reduced oxidative stress, preservation of cardiomyocyte ultrastructure, and reduced interstitial fibrosis in the left ventricular myocardium. In conclusion, ezetimibe not only reduces total cholesterol, but also prevents the development of atherosclerosis and cardiovascular events due to intermittent hypoxia at least partly through suppression of oxidative stress.

The effect of a low-fat spread with added plant sterols on vascular function markers: results of the Investigating Vascular Function Effects of Plant Sterols (INVEST) study

BACKGROUND

Plant sterols (PSs) lower LDL cholesterol, an established risk factor for coronary artery disease (CAD). No direct evidence is available supporting a reduced risk of CAD for foods with added PSs. Endothelial dysfunction is seen as an early indicator of atherosclerotic damage.

OBJECTIVES

This study was primarily designed to investigate the effect of a low-fat spread with added PSs on brachial artery endothelial function as measured by flow-mediated dilation (FMD). Second, effects on arterial stiffness, blood pressure, serum lipids, and plasma PS concentrations were investigated. We hypothesized that PSs would not worsen FMD but would rather modestly improve FMD.

DESIGN

This study had a double-blind, randomized, placebo-controlled, parallel design. After a 4-wk run-in period, 240 hypercholesterolemic but otherwise healthy men and women consumed 20 g/d of low-fat spread without (control) or with added PSs (3 g/d) during 12 wk. Pre- and postintervention, vascular function measurements and blood sampling were performed.

RESULTS

In total, 232 participants completed the study period. For the primary endpoint FMD, 199 participants were included in the statistical analysis. PS intake did not affect FMD (+0.01 percentage points; 95% CI: -0.73, 0.75) compared with control. Measures of arterial stiffness (pulse wave velocity and augmentation index) and blood pressure were also not significantly changed compared with control. After PS intervention, LDL cholesterol significantly decreased on average by 0.26 mmol/L (95% CI: -0.40, -0.12) or 6.7% compared with control. Plasma sitosterol and campesterol concentrations significantly increased in the PS group up to on average 11.5 μmol/L and 13.9 μmol/L (expressed as geometric means), respectively.

CONCLUSIONS

The intake of a low-fat spread with added PSs neither improved nor worsened FMD or other vascular function markers in hypercholesterolemic men and women. As expected, serum LDL cholesterol decreased, whereas plasma PSs increased after PS intake. This study was registered at clinicaltrials.gov as NCT01803178.

Circulating malondialdehyde-modified LDL-related variables and coronary artery stenosis in asymptomatic patients with type 2 diabetes

AIMS

To elucidate the levels of malondialdehyde-modified LDL (MDA-LDL)-related variables for predicting coronary artery stenosis (CAS) by coronary CT angiography (CCTA) in asymptomatic patients with type 2 diabetes (T2DM).

METHODS

Enrolled were 36 Japanese patients with T2DM who underwent CCTA and in whom MDA-LDL levels were measured. Definition of CAS was luminal narrowing of ≥50%. Trends through tertiles of each MDA-LDL-related variable were analyzed with a general linear model. The ability of each MDA-LDL-related variable to predict CAS was compared to areas under the curve (AUCs) in receiver operating characteristic curve (ROC) analysis.

RESULTS

Seventeen patients had CAS. Each MDA-LDL-related variable was an independent predictor of CAS (P = 0.039 for MDALDL, P = 0.013 for MDA-LDL/LDL-C, P = 0.047 for MDA-LDL/HDL-C, and P = 0.013 for (MDA-LDL/LDL-C)/HDL-C). AUCs of MDA-LDL, MDA-LDL/LDL-C, MDA-LDL/HDL-C, and (MDA-LDL/LDL-C)/HDL-C were 0.675 (95% CI 0.496-0.854), 0.765 (0.602-0.927), 0.752 (0.592-0.913), and 0.799 (0.643-0.955), respectively, for predicting CAS. Trends throughout the tertiles showed significant associations between MDA-LDL/LDL-C, MDA-LDL/HDL-C, or (MDALDL/LDL-C)/HDL-C and CAS (P = 0.003 for MDA-LDL/LDL-C, P = 0.042 for MDA-LDL/HDL-C, and P = 0.001 for (MDA-LDL/LDL-C)/HDL-C).

CONCLUSIONS

Data suggest that measurements of MDA-LDL/LDL-C, MDA-LDL/HDLC, and (MDA-LDL/LDL-C)/HDL-C are useful for predicting CAS.

Ezetimibe combined with standard diet and exercise therapy improves insulin resistance and atherosclerotic markers in patients with metabolic syndrome

Aims/Introduction

Ezetimibe lowers serum lipid levels by inhibiting intestinal absorption of dietary and biliary cholesterol. However, the effect of ezetimibe on insulin resistance remains unclear. The aim of the present study was to examine this issue in patients with metabolic syndrome in local-dwelling Japanese, who were not being treated with lipid-lowering drugs.

Materials and Methods

In 2009, 1,943 participants received a health examination in the Tanushimaru Study, a Japanese cohort of the Seven Countries Study, of whom 490 participants had metabolic syndrome. Among them, 61 participants (41 men and 20 women) were examined in the present study. They were treated with 10 mg of ezetimibe once a day for 24 weeks, combined with standard diet and exercise therapy.

Results

Bodyweight (P < 0.001), body mass index (P < 0.001), systolic blood pressure (P = 0.003), diastolic blood pressure (P < 0.001), triglycerides (P = 0.002), non-high-density lipoprotein cholesterol (P = 0.001), low-density lipoprotein cholesterol (P < 0.001) and homeostasis model assessment of insulin resistance (P = 0.011) significantly decreased after the observational period. There were no statistically significant differences in the effects of ezetimibe between men and women. Univariate analysis showed that the reduction of homeostasis model assessment of insulin resistance was not associated with the improvement of other metabolic components.

Conclusions

Ezetimibe combined with standard diet and exercise therapy improves not only bodyweight and atherogenic lipid profiles, but also insulin resistance, blood pressure and anthropometric factors in metabolic syndrome in local-dwelling Japanese. Interestingly, the improvement of insulin resistance had no correlation with other metabolic components.

Influence of ezetimibe on selected parameters of oxidative stress in rat liver subjected to ischemia/reperfusion

INTRODUCTION

Ischemia/reperfusion (I/R) is considered to be one of the main causes of liver damage after transplantation. The authors evaluated the effect of ezetimibe on selected oxidative stress parameters in ischemic/reperfused (I/R) rat liver.

MATERIAL AND METHODS

Rats were administered ezetimibe (5 mg/kg) (groups E and E-I/R) or saline solution (groups C and C-I/R) intragastrically for 21 days. Livers of animals in groups C-I/R and E-I/R were subjected to 60 min of partial ischemia (left lateral and median lobes) followed by 4 h of reperfusion. Alanine and asparagine aminotransferase (ALT, AST) activity was determined in blood before I/R and during reperfusion (at 15 and 240 min). After the reperfusion period, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH) and glutathione peroxidase (GPx) were determined in liver homogenates using colorimetric methods.

RESULTS

Ezetimibe caused a significant increase in GSH level in groups subjected to I/R (E-I/R (99.91 ±9.01) vs. C-I/R (90.51 ±8.87), p < 0.05). Additionally, under I/R the decrease of GPx activity in the drug-treated group was lower compared to the non-treated group (E-I/R (3.88 ±1.11) vs. E (5.31 ±1.83), p = 0.076). Neither ezetimibe nor I/R affected SOD or MDA levels. I/R produced a significant increase in aminotransferase levels (ALT240-0: C-I/R (42.23 ±43.56) vs. C (9.75 ±11.09), and E-I/R (39.85 ±26.53) vs. E (4.38 ±1.36), p < 0.05 in both cases; AST 240-0: E-I/R (53.87 ±17.23) vs. E (24.10 ±9.66), p < 0.05) but no effect of ezetimibe on those enzymes was found.

CONCLUSIONS

Ezetimibe demonstrates antioxidant properties in rat livers subjected to I/R. However, neither a hepatoprotective nor a hepatotoxic effect of ezetimibe was demonstrated, regardless of I/R.

Simvastatin but not ezetimibe reduces sympathetic activity despite similar reductions in cholesterol levels

The relationship between the sympatholytic effects of statins and their lipid-lowering activity remains unclear. Ezetimibe lowers cholesterol, but its sympatholytic activity is unknown. The purpose of study was to compare the influence of equipotent doses of simvastatin and ezetimibe on sympathetic activity. This randomized double-blinded study was performed in 22 hypertensive patients (age, 45.6 ± 2.2 years; female/male, 2/20) with untreated hypercholesterolemia. The subjects were administered 20 mg/d of simvastatin (n = 11) or 20 mg/d of ezetimibe (n = 11) for 6 weeks. Pre- and post-treatment measurements of muscle sympathetic nerve activity (MSNA), baroreceptor control of heart rate (baroreflex sensitivity), and impedance cardiography were recorded. Simvastatin and ezetimibe produced similar reductions of total (-58.0 ± 23.4 vs. -45.2 ± 17.2 mg/dL; P = .15, respectively) and low-density lipoprotein cholesterol (-52.6 ± 20.9 vs. -37.9 ± 17.6 mg/dL; P = .09, respectively). There was a significant difference in the effect of simvastatin and ezetimibe on muscle sympathetic nerve activity (-8.5 ± 5.1 vs. -0.7 ± 3.5 bursts/min; P = .0005). Simvastatin improved baroreflex sensitivity as compared with ezetimibe (10.0 ± 14.3 vs. -2.8 ± 6.1 ms/mm Hg; P = .01). There was no difference in the effect of both treatments on blood pressure, heart rate, cardiac output, stroke volume, total peripheral resistance, high-density lipoprotein, and triglycerides. Simvastatin reduced sympathetic activity via lipid-independent mechanisms, but ezetimibe exerts no sympatholytic effects.

Eugenosedin-A ameliorates hyperlipidemia-induced vascular endothelial dysfunction via inhibition of α1-adrenoceptor/5-HT activity and NADPH oxidase expression

Eugenosedin-A (Eu-A) effects on vascular endothelial dysfunction and oxidative stress in a hyperlipidemic rat model were investigated. Rats were randomly divided into four groups: two control groups and two treatment groups. The control rats received a regular diet or high fat diet (HFD); the treatment rats fed received an HFD with 5 mg/kg Eu-A or atorvastatin for 10 weeks. No changes in serotonin levels were observed in the four groups; norepinephrine levels were enhanced in the HFD group which was attenuated by Eu-A and atorvastatin. In the HFD group, the vascular reactivity was increased by vasoconstrictors (5-nonyloxytryptamine, 5-HT, and phenylephrine) and decreased by an endothelium-dependent vasorelaxant, carbachol. Protein levels of α1-adrenergic receptors (not 5-HT1B/2A), reactive oxygen species (ROS) p47(phox), p67(phox), and gp91(phox), and oxidative damage markers 3-nitrotyrosine (3-NT) and 4-hydroxy-2-nonenal (4-HNE) were increased, but endothelial nitric oxide synthase (eNOS), P-eNOS and vasodilator-stimulated phosphoprotein phosphorylation (P-VASP) were decreased. Catalase and superoxide dismutase (SOD-1 and SOD-2) proteins were increased, but glutathione peroxidase (GPx) was decreased in the aorta. Eu-A and atorvastatin reduced vasoconstrictor-induced aortic contractions that might be related to 5-HT1B/2A and α1-adrenergic receptors inhibitory activities. Eu-A and atorvastatin improved eNOS/P-eNOS, P-VASP, GPx, and malondialdehyde (MDA) levels, and decreased ROS and oxidative damage markers. Taken together, we suggest that Eu-A can ameliorate hyperlipidemia-induced vascular endothelial dysfunction and oxidative dysregulation.

Comparison of anti-inflammatory effects and high-density lipoprotein cholesterol levels between therapy with quadruple-dose rosuvastatin and rosuvastatin combined with ezetimibe

BACKGROUND

Statins are frequently administered to reduce low-density lipoprotein cholesterol (LDL-C) and vascular inflammation, because LDL-C and high sensitive C-reactive protein (hs-CRP) are associated with high risk for cardiovascular events. When statins do not reduce LDL-C to desired levels in high-risk patients with coronary artery disease (CAD), ezetimibe can be added or the statin dose can be increased. However, which strategy is more effective for treating patients with CAD has not been established. The present study compares anti-inflammatory effects and lipid profiles in patients with CAD and similar LDL-C levels who were treated by increasing the statin dose or by adding ezetimibe to the original rosuvastatin dose to determine the optimal treatment for such patients.

METHODS

46 patients with high-risk CAD and LDL-C and hs-CRP levels of >70 mg/dL and >1.0 mg/L, respectively, that were not improved by 4 weeks of rosuvastatin (2.5 mg/day) were randomly assigned to receive 10 mg (R10, n = 24) of rosuvastatin or 2.5 mg/day of rosuvastatin combined with 10 mg/day of ezetimibe (R2.5/E10, n = 22) for 12 weeks. The primary endpoint was a change in hs-CRP.

RESULTS

Baseline characteristics did not significantly differ between the groups. At 12 weeks, LDL-C and inflammatory markers (hs-CRP, interleukin-6, tumour necrosis factor-alpha and pentraxin 3) also did not significantly differ between the two groups (LDL-C: R10 vs. R2.5/E10: -19.4 ± 14.2 vs. -22.4 ± 14.3 mg/dL). However, high-density lipoprotein cholesterol (HDL-C) was significantly improved in the R10, compared with R2.5/E10 group (4.6 ± 5.9 vs. 0.0 ± 6.7 mg/dL; p < 0.05).

CONCLUSION

Both enhanced therapies exerted similar anti-inflammatory effects under an equal LDL-C reduction in patients with high-risk CAD despite 2.5 mg/day of rosuvastatin. However, R10 elevated HDL-C more effectively than R2.5/E10.

TRIAL REGISTRATION

UMIN000003746.

Effects of ezetimibe on visceral fat in the metabolic syndrome: a randomised controlled study

BACKGROUND

Although visceral obesity, a key abnormality in the metabolic syndrome, is an important risk for cardiovascular diseases, reduction in visceral fat is hard to achieve despite intensive efforts directed at lifestyle modification. The present study was designed to investigate whether ezetimibe, an inhibitor of intestinal cholesterol absorption through its binding to Niemann-Pick C1-like 1, reduces visceral fat in patients with metabolic syndrome.

MATERIALS AND METHODS

Seventy-eight outpatients (63·7 ± 10·4 years old) with metabolic syndrome were enroled and randomly assigned to receive either ezetimibe (10 mg/day) or nothing for 6 months. Changes in visceral fat were assessed by computed tomography.

RESULTS

Treatment with ezetimibe significantly improved lipid profiles. Visceral fat was decreased 7·2%, from 161·3 ± 58·6 cm(2) to 148·4 ± 52·7 cm(2) (P < 0·05), and adiponectin was increased 7·7%, from 3·61 ± 3·10 μg/mL to 3·86 ± 3·62 μg/mL (P < 0·05), after ezetimibe therapy; these beneficial effects were not observed in the control group. The increase in the adiponectin level was correlated with the reduction in visceral fat after ezetimibe treatment. Furthermore, ezetimibe reduced fasting insulin levels (P < 0·05) and improved the homoeostasis model assessment of insulin resistance (HOMA-IR) (P < 0·05).

CONCLUSIONS

Ezetimibe reduces visceral fat with beneficial effects on adiponectin and insulin resistance in patients with metabolic syndrome, suggesting a new therapeutic approach in such patients.