The effect of simvastatin, ezetimibe and their combination on the lipid profile, arterial stiffness and inflammatory markers

Arterial Stiffness and its Impact on Cardiovascular Health

PURPOSE OF REVIEW

Cardiovascular diseases are the leading cause of mortality globally. Identifying patients at risk is important to initiate preventive strategies. Over the last few decades, the role of the endothelium and its impact on arterial stiffness have been recognised as playing a pivotal role in cardiovascular disease. This review will focus on the effect of arterial stiffness in different patient cohorts with regard to cardiovascular morbidity and mortality, as well as its use in clinical practice.

RECENT FINDINGS

Arterial stiffness is associated with a range of cardiovascular risk factors and is an independent predictor of cardiovascular mortality. The gold standard for evaluating arterial stiffness is pulse wave velocity. Recently, cardio-ankle vascular index has been implemented as an easy and highly reproducible measure of arterial stiffness. Moreover, certain pharmacologic agents may modify arterial stiffness and alter progression of cardiovascular disease. The endothelium plays an important role in cardiovascular disease. Implementing assessment of arterial stiffness in clinical practice will improve stratification of patients at risk of cardiovascular disease and help modify disease progression.

Beneficial Effect of Statin Therapy on Arterial Stiffness

Arterial stiffness describes the increased rigidity of the arterial wall that occurs as a consequence of biological aging and several diseases. Numerous studies have demonstrated that parameters to assess arterial stiffness, especially pulse-wave velocity, are predictive of those individuals that will suffer cardiovascular morbidity and mortality. Statin therapy may be a pharmacological strategy to improve arterial elasticity. It has been shown that the positive benefits of statin therapy on cardiovascular disease is attributable not only to their lipid-lowering capacity but also to various pleiotropic effects, such as their anti-inflammatory, antiproliferative, antioxidant, and antithrombotic properties. Additionally, statins reduce endothelial dysfunction, improve vascular and myocardial remodeling, and stabilize atherosclerotic plaque. The aim of the present review was to summarize the evidence from human studies showing the effects of statins on arterial stiffness.

Effects of statin therapy on augmentation index as a measure of arterial stiffness: A systematic review and meta-analysis

OBJECTIVE

To evaluate the effects of statin therapy on augmentation index (AIx) as a measure of arterial stiffness using a meta-analysis of clinical trials.

METHODS

The search included PubMed-Medline, Embase, SCOPUS, Web of Science and Google Scholar databases to identify randomized controlled trials investigating the effects of statin therapy on arterial stiffness measured as AIx. A random-effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. Random-effects meta-regression was performed using unrestricted maximum likelihood method to evaluate the impact of potential confounders.

RESULTS

18 trials examining the effects of statin therapy on arterial stiffness were included. A significant reduction in aortic AIx following statin therapy was proven (WMD: -2.40%, 95% CI: -4.59, -0.21, p=0.032; I(2): 51.20%). HR-adjusted AIx 75% values also revealed a significant improvement by statin therapy (WMD: -5.04%, 95% CI: -7.81, -2.27, p<0.001; I(2): 0%), but not when analysis was restricted to unadjusted AIx values (WMD: -2.30%, 95% CI: -4.83, 0.23, p=0.075; I(2): 53.83%). There was no significant change in carotid (WMD: -2.75%, 95% CI: -8.06, 2.56, p=0.309; I(2): 26.86%) and peripheral (WMD: 0.25%, 95% CI: -3.31, 3.82, p=0.889; I(2): 72.19%) AIx due to statin treatment. There was also no difference in the effect size calculated for different statins subgroups. The impact of statins on AIx was independent of LDL-cholesterol level (slope: 0.05; 95% CI: -0.02, 0.13; p=0.181).

CONCLUSION

Statin therapy causes a significant reduction in aortic AIx which is independent of LDL-cholesterol changes.

Prospective risk factors for increased central augmentation index in men and women

BACKGROUND

Arterial wave reflections are important determinants of central pressure pulsatility and left ventricular afterload. The augmentation index (AIx) is the most widely used surrogate of arterial wave reflections. Despite multiple cross-sectional studies assessing the correlates of AIx, little prospective data exist regarding changes in AIx over time. We aimed to assess the predictors of changes in AIx over time in adults from the general population.

METHODS

We performed radial arterial tonometry assessments a median of 3.18 ± 0.4 years apart on 143 nondiabetic adult participants in the population-based PREVENCION study. Central AIx was obtained using the generalized transfer function of the Sphygmocor device.

RESULTS

Predictors of the change in AIx over time were investigated. Among men (n = 67), the change in AIx was predicted by abdominal obesity (standardized β for waist circumference = 0.34; P = 0.002), impaired fasting glucose (standardized β = 0.24; P = 0.009), and the change in heart rate (standardized β = -0.78; P < 0.001). Among women (n = 76), the change in AIx was predicted by non-high-density lipoprotein cholesterol (standardized β = 0.33; P = 0.001), C-reactive protein levels (standardized β = 0.24; P = 0.02), change in mean arterial pressure (standardized β = 0.33; P = 0.001), and change in heart rate (standardized β = -0.52; P < 0.001).

CONCLUSIONS

Metabolic and inflammatory factors predicted changes in AIx over time, with important sex differences. Metabolic factors, such as abdominal obesity and impaired fasting glucose, predicted changes in AIx in men, whereas C-reactive protein and non-high-density lipoprotein cholesterol levels predicted changes in women. Our findings highlight the impact of sex on arterial properties and may guide the design of interventions to favorably impact changes in late systolic pressure augmentation.

"Inflammation and arterial stiffness in humans"

Arterial stiffness is an established marker of cardiovascular morbidity and mortality and a potential therapeutic target. While hypertension and aging are established factors contributing to arterial stiffness, the role of inflammation in stiffening of the arteries is less well understood. We summarize existing literature regarding inflammation and arterial stiffness, including a discussion of the potential mechanisms by which inflammation may lead to arterial stiffening and studies assessing: (1) The association between subclinical inflammation and arterial stiffness in the general population; (2) The presence of increased arterial stiffness in primary inflammatory diseases; (3) The effect of anti-inflammatory therapy on arterial stiffness in primary inflammatory disease including the effect of statins; (4) Experimental evidence of immunization-induced arterial stiffening in normal adults. We discuss potential opportunities to assess the impact of anti-inflammatory interventions on arterial stiffness in subjects without primary inflammatory conditions. We also review the effect of inflammation on wave reflections.

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.

The effects of plant stanol ester consumption on arterial stiffness and endothelial function in adults: a randomised controlled clinical trial

Background

The hypocholesterolemic effect of plant stanol ester consumption has been studied extensively, but its effect on cardiovascular health has been less frequently investigated. We studied the effects of plant stanol esters (staest) on arterial stiffness and endothelial function in adults without lipid medication.

Methods

Ninety-two asymptomatic subjects, 35 men and 57 women, mean age of 50.8±1.0 years (SEM) were recruited from different commercial companies. It was randomized, controlled, double-blind, parallel trial and lasted 6 months. The staest group (n=46) consumed rapeseed oil-based spread enriched with staest (3.0 g of plant stanols/d), and controls (n=46) the same spread without staest. Arterial stiffness was assessed via the cardio-ankle vascular index (CAVI) in large and as an augmentation index (AI) in peripheral arteries, and endothelial function as reactive hyperemia index (RHI). Lipids and vascular endpoints were tested using analysis of variance for repeated measurements.

Results

At baseline, 28% of subjects had a normal LDL cholesterol level (≤3.0 mmol/l) and normal arterial stiffness (<8). After the intervention, in the staest group, serum total, LDL, and non-HDL cholesterol concentrations declined by 6.6, 10.2, and 10.6% compared with controls (p<0.001 for all). CAVI was unchanged in the whole study group, but in control men, CAVI tended to increase by 3.1% (p=0.06) but was unchanged in the staest men, thus the difference in the changes between groups was statistically significant (p=0.023). AI was unchanged in staest (1.96±2.47, NS) but increased by 3.30±1.83 in controls (p=0.034) i.e. the groups differed from each other (p=0.046). The reduction in LDL and non-HDL cholesterol levels achieved by staest was related to the improvement in RHI (r=−0.452, p=0.006 and −0.436, p=0.008).

Conclusions

Lowering LDL and non-HDL cholesterol by 10% with staest for 6 months reduced arterial stiffness in small arteries. In subgroup analyses, staest also had a beneficial effect on arterial stiffness in large arteries in men and on endothelial function. Further research will be needed to confirm these results in different populations.

Trial registration

Clinical Trials Register # NCT01315964

Dose-dependent effects of short term atorvastatin treatment on arterial wall properties and on indices of left ventricular remodeling in ischemic heart failure

OBJECTIVES

Statins, beyond their lipid lowering role, exert beneficial effect on endothelial function in patients with atherosclerosis. Aim of the present study was to examine the short term pleiotropic effects of different doses of atorvastatin treatment, on endothelial function, arterial stiffness and indices of left ventricular remodeling in heart failure (HF) patients.

METHODS

We studied the effect of 4 weeks administration of atorvastatin in 22 patients with ischemic HF. The study was carried out on two separate arms, one with atorvastatin 40 mg/d and one with atorvastatin 10 mg/d (randomized, double-blind, cross-over design). Endothelial function was evaluated by flow mediated dilation (FMD) in the brachial artery and arterial stiffness by augmentation index (AIx). Serum levels of matrix metalloproteinase-9 (MMP-9) and intracellular adhesion molecule-1 (sICAM-1) were measured as biomarkers of left ventricular remodeling and endothelial function, respectively, while, b-type natriuretic peptide (BNP) was measured as a marker of left ventricular function.

RESULTS

Compared to baseline, atorvastatin 40 mg/d significantly improved FMD values (3.18 ± 3.03% vs. 5.98 ± 2.49%, p = 0.001) and AIx values (25.98 ± 8.55% vs. 23.09 ± 8.87%, p = 0.046). In addition, compared to baseline measurements, treatment with atorvastatin 40 mg/d resulted in significantly decreased levels of serum logMMP-9 levels (2.47 ± 0.23 ng/ml vs. 2.39 ± 0.24 ng/ml, p = 0.04) and of logICAM-1 levels (2.46 ± 0.13 ng/ml vs. 2.37 ± 0.16 ng/ml, p < 0.001). No significant changes were found after treatment with atorvastatin 10 mg/d in the aforementioned parameters.

CONCLUSIONS

Short term treatment with 40 mg/d of atorvastatin exerts beneficial impact on arterial wall properties and on indices of left ventricle remodeling in heart failure patients.

Randomised study of ezetimibe, start doses of original statins, and their combination in patients with coronary heart disease and hyperlipidemia Part 2. Therapy effects on the levels of C-reactive protein and proinflammatory cytokines

Aim. To assess the effects of original statins as monotherapy or in combination with ezetimibe on the levels of proinflammatory cytokines and high-sensitive C-reactive protein (hsCRP) in patients with coronary heart disease (CHD) and hyperlipidemia (HLP). Material and methods. The study included 60 male and female patients with CHD, primary polygenic HLP, and the levels of low-density lipoprotein cholesterol (LDL-CH) of 2,9-4,9 mmol/l. Monotherapy with original statins or ezetimibe lasted for 6 months, while the combination therapy lasted for 3 months. In all randomised patients, the levels of hsCRP, interleukin 6 (IL-6), and monocyte chemotactic protein-1 (MCP-1) were measured at baseline, 12 and 24 weeks after the therapy started. Results. At baseline, median hsCRP levels in the groups of Ezetrol, Zocor, Liprimar, and Crestor monotherapy were 0,5-0,88 mg/l, with no significant dynamics after 3 months of the treatment. Baseline IL-6 levels across the monotherapy groups were 1,94-2,54 pg/ml; at 3 months, there was a non-significant reduction by 7-32 %. After 3 months of the therapy, the decrease in MCP-1 levels was not statistically significant (-1,3-7,7 %). The combined therapy did not result in a significant dynamics of hsCRP concentrations, with the exception of the group receiving Ezetrol and Liprimar. Although the combined therapy further reduced MCP-1 levels (by 30-78 pg/ml), these changes were not statistically significant. No significant difference was observed across statin and Ezetrol groups in terms of their effects on IL-6 and MCP-1 levels. Conclusion. The comparison of the three treatment schemes demonstrated similar, but not statistically significant reduction on the levels of hsCRP, IL-6, and MCP-1. No marked benefits were observed for either monotherapy or combination therapy over 12-24 weeks of the follow-up.

Comparative efficacy of the addition of ezetimibe to statin vs statin titration in patients with hypercholesterolaemia: systematic review and meta-analysis

OBJECTIVE

To systematically review and analyse evidence for cholesterol-lowering efficacy of at least 4 weeks of add-on ezetimibe vs doubling statin dose, in adults with primary hypercholesterolaemia.

RESEARCH DESIGN AND METHODS

MEDLINE, EMBASE and Cochrane databases were searched to identify randomised controlled trials of ezetimibe-statin combination vs statin titration (January 1993 - March 2010). Studies were selected using predefined criteria. Two reviewers conducted screening of articles, critical appraisal and data extraction; a third reviewer resolved disagreements. The difference between treatments was analysed for four co-primary outcomes: mean percentage change from baseline in low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and total cholesterol (TC); and proportion of patients achieving LDL-C treatment goal. Data were combined by two sets of direct comparison fixed and random effects meta-analysis: (1) compared data in the same treatment period between groups; (2) compared the incremental change in lipid levels of add-on ezetimibe vs doubling statin dose. Heterogeneity was assessed using the I(2) statistic.

RESULTS

Thirteen studies including 5080 patients were included in the meta-analyses. Data on simvastatin, atorvastatin and rosuvastatin were analysed. Results for primary and secondary outcomes were in favour of the ezetimibe-statin combination. A significantly greater percentage reduction in LDL-C levels was achieved in patients treated with ezetimibe-statin vs statin monotherapy (weighted mean difference [WMD]: -14.1% [-16.1, -12.1], p < 0.001). Reduction in LDL-C levels attributed to add-on ezetimibe was significantly greater than that for statin dose doubling (WMD: -15.3% [-19.1, -11.4], p < 0.001). Achievement of LDL-C goal favoured add-on ezetimibe over statin titration and was statistically significant (odds ratio: LDL-C treatment goal 2.45 [1.95, 3.08], p = 0.007).

CONCLUSIONS

Meta-analyses were restricted by the limited number of studies with similar trial design and method of statin titration. Results indicate that add-on ezetimibe is significantly more effective in reducing LDL-C levels than doubling statin dose, enabling more patients to achieve LDL-C goal.

Improvement of endothelial damage and regeneration indexes in patients with coronary artery disease after 4 weeks of statin therapy

BACKGROUND

In patients with coronary artery disease (CAD), higher numbers of circulating endothelial progenitor cells (EPC) favourably influence clinical outcome. Controversially, increased apoptosis of endothelial cells (EC) may reflect vascular damage. Statins have been shown to improve vascular damage and enhance EPC function and numbers. The availability of ezetimibe, a potent novel cholesterol absorption inhibitor, allows to distinguish between lipid-lowering and pleiotropic properties of statins.

METHODS AND FINDINGS

43 patients with CAD were assigned to receive either: de novo atorvastatin (group A; n=17), ezetimibe as add-on to chronic statin therapy (group B; n=14), or dose escalation of atorvastatin (group C; n=12) over 4 weeks. Circulating apoptotic EC (CD45-CD146+vWF+Annexin-V+) and EPC (CD34+KDR+) were quantified using flow cytometry. LDL cholesterol levels were significantly reduced in all treatment arms. Both statin groups, group A and group C, showed significantly reduced circulating apoptotic EC by 50% each (p<0.01). On the other hand, there was a significant doubling in the numbers of circulating EPC in group A and group C (p<0.005, each). Consequently, the endothelial damage-index calculated from numbers of circulating apoptotic mature EC related to EPC numbers, was improved in group A by 79% (p<0.01) and in group C by 70% (p<0.05). In contrast, sole LDL reduction by ezetimibe exerted no effect on any of the different circulating endothelial cell types.

CONCLUSION

Thus, the improvement in numbers of EPC and reduction of mature apoptotic EC after 4 weeks of statin therapy, document a novel pleiotropic effect of statin therapy in patients with CAD.

Pleiotropic effects of ezetimibe: do they really exist?

Ezetimibe represents a new lipid lowering agent which inhibits cholesterol absorption. It effectively reduces low-density lipoprotein cholesterol when administered either alone or in combination with statins. However, its effect on cardiovascular mortality remains under question since it failed to demonstrate any significant changes in the primary endpoints of the recently published ENHANCE and SEAS studies. A possible explanation for this unsuccessful outcome is that ezetimibe lacks pleiotropic effects. This article aims to review the potential pleiotropic effects of the drug mainly on inflammation markers, lipoprotein subfractions and endothelial function.

The impact of ezetimibe on endothelial function and other markers of cardiovascular risk

OBJECTIVE

To review the published literature characterizing the impact of ezetimibe-containing lipid-lowering regimens on endothelial function and other markers of cardiovascular risk and discuss the potential relevance of these effects to the clinical benefit of ezetimibe.

DATA SOURCES

A MEDLINE search (2000-August 2009) was completed using the key words ezetimibe, statins, endothelial function, flow-mediated dilation, pleiotropic, and inflammation to identify relevant literature. Bibliographies of identified literature were reviewed for additional references.

STUDY SELECTION AND DATA EXTRACTION

All clinical studies published in English that evaluated the effect of ezetimibe on ancillary endpoints of cardiovascular disease risk, including endothelial function, inflammation, thrombosis, and oxidative stress, were evaluated.

DATA SYNTHESIS

Recent studies in patients with coronary artery disease (CAD), heart failure, and hypercholesterolemia have demonstrated that treatment with ezetimibe for 4-12 weeks elicits no improvement of endothelial function or other measures of cardiovascular disease risk. In contrast, other studies have reported that ezetimibe improves endothelial function in certain patient populations, including those with rheumatoid arthritis, CAD with type 2 diabetes, and metabolic syndrome. However, the statin monotherapy comparator groups in these studies that yielded equivalent reductions in cholesterol were superior, or at least equivalent to, ezetimibe-containing regimens in the improvement of these ancillary endpoints.

CONCLUSIONS

Overall, the evidence to date suggests that administration of ezetimibe, either as monotherapy or in combination with a statin, exerts minimal beneficial effects on endothelial function and other ancillary measures of cardiovascular disease risk beyond those conferred by its cholesterol-lowering effects. Studies with larger sample sizes and follow-up beyond 12 weeks remain necessary to further define the impact of ezetimibe on the processes integral to the pathogenesis and progression of cardiovascular disease.

Relationship between job strain and radial arterial wave reflection in middle-aged male workers

OBJECTIVE

This study examined the relationship between job stain and radial arterial wave reflection as expressed by the augmentation index (AI), a marker of cardiovascular risk, in middle-aged male workers.

METHODS

Radial AI was measured using automated applanation tonometry in 808 working men (mean age; 47+/-5 years) at a company in Kanagawa, Japan in 2007. An elevated AI represents the deterioration of arterial properties and increased cardiovascular risk. Job demand and job control (decision latitude) were evaluated by a self-administered, Brief Job Stress Questionnaire. High job strain was defined as the combination of high job demand and low job control.

RESULTS

In the entire study population, the mean+/-SD and the median of AI were 74+/-13% and 75%, respectively. High job strain was seen in 267 subjects. In a multiple logistic regression analysis with adjustment for multiple potential confounders, high job strain showed a significantly increased odds ratio (1.47, 95% CI; 1.04-2.09, P=0.029) for an elevated AI (> or =75%).

CONCLUSION

High job strain was significantly associated with an elevated radial AI. The measurement of AI may be useful when incorporated in workplace interventions to reduce the risk of cardiovascular disease, especially at sites where workers tend to perceive high job strain.

Radial augmentation index unmasks premature coronary artery disease in younger males

OBJECTIVE

The augmentation index, a marker of arterial wave reflection, is considered to indicate cardiovascular risk burden, particularly in younger persons. We assessed whether the easily obtainable radial augmentation index (rAIx) is superior to systolic blood pressure (SBP) or pulse pressure (PP) in detecting atherosclerotic vascular disease at an early age.

METHODS

We determined rAIx by applanation tonometry, SBP and PP in 152 male patients with or without invasively documented coronary artery disease (CAD). Ejection fraction (EF) was visually estimated by echocardiography or left ventricular angiography.

RESULTS

In younger patients (age < or =60 years, EF > or =30%), rAIx was significantly higher in patients with CAD (79.8+/-13.5%, n=31) compared with patients without CAD (68.5+/-22.0%, n=21; P = 0.04), whereas SBP (121+/-16 vs. 131+/-18 mmHg, P=0.04) and PP (48.7+/-9.4 vs. 56.3+/-12.1 mmHg, P=0.01) were even lower in patients with CAD compared with patients without CAD. In patients aged < or =60 years, rAIx was highest when EF was less than 30% (90.0+/-9.2%) compared with patients with EF 30-54% (80.7+/-11.5%) or EF > or =55% (72.1+/-20.4%, P=0.01). In contrast, in patients above 60 years of age, rAIx, SBP or PP did not differ between patients with or without CAD and the rAIx tended to be lowest in patients with severely reduced EF (P=0.07).

CONCLUSION

We conclude that premature vascular disease in younger patients with CAD is reflected only by an elevated rAIx, and not by SBP or PP. The rAIx is not suited to distinguish between older patients with high or low cardiovascular risk. Age seems to influence the interplay between rAIx and systolic heart function.

Impact of ezetimibe on atherosclerosis: is the jury still out?

Ezetimibe is a new lipid-lowering agent that inhibits intestinal absorption of dietary cholesterol. It substantially lowers low-density lipoprotein cholesterol levels when used alone or in combination with statins. However, its effect on cardiovascular mortality remains unknown. We reviewed peer-reviewed published literature on the effect of ezetimibe on different phases of atherosclerosis. MEDLINE, EMBASE, BIOSIS, and other Web of Knowledge databases were searched for relevant abstracts and articles published in the English language that compared ezetimibe and statins as modulators of atherosclerosis. On the basis of the available evidence, ezetimibe appears to reduce inflammation when used in combination with statins, but its effect on endothelial function is mixed and less clear. The effect of ezetimibe on coronary disease progression or prevention of cardiovascular events is currently unknown. Use of ezetimibe as a second- or third-line agent to achieve low-density lipoprotein cholesterol treatment goals seems appropriate on the basis of the available evidence.

Role of the augmentation index in hypertension

Recent studies have revealed the clinical usefulness of central blood pressure (BP) as an index of risk for cardiovascular disease. The arterial pulse waveform is the sum of the forward pressure wave generated by left ventricular ejection and a backward propagating wave that is subsequently reflected from the peripheral site, and the time point at which these forward and backward propagating waves merge and the amplitude of the reflected (backward) wave affect the level of central BP. The augmentation index (AIx) has been proposed as a measure of the wave reflection, and its clinical usefulness has also been evaluated. In the process, the non-linear relationship between age and AIx, the prognostic value of AIx, and the various effects of antihypertensive drugs on AIx have been shown. However, the clinical usefulness of AIx has not been established, and several questions about its use remain. Future studies will be needed to address these questions, and may contribute to important changes in the management of cardiovascular disease. In this review, we present recent findings on the AIx and discuss the role of this parameter in clinical practice.

Ezetimibe's effect on platelet aggregation and LDL tendency to peroxidation in hypercholesterolaemia as monotherapy or in addition to simvastatin

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Statins demonstrate a pleiotropic effect which contributes beyond the hypocholesterolaemic effect to prevent atherosclerosis.

WHAT THIS STUDY ADDS

Ezetimibe has an antioxidative effect when given as monotherapy or as an add-on to the statin, simvastatin. AIMS To investigate the effect of lowering low-density lipoprotein-cholesterol (LDL-C) on platelet aggregation and LDL tendency to peroxidation by ezetimibe alone or with simvastatin in hypercholesterolaemia.

METHODS

Sixteen patients with LDL-C >3.4 mmol l(-1) received ezetimibe for 3 months (Part I). Twenty-two patients on fixed simvastatin dose with LDL-C >2.6 mmol l(-1) were enrolled (Part II). Part II patients continued simvastatin treatment 20 mg day(-1) for 6 weeks, then received 20 mg day(-1) simvastatin combined with ezetimibe 10 mg day(-1) for another 6 weeks. The tendency of LDL to peroxidation measured by lag time in minutes required for initiation of LDL oxidation and by LDL oxidation at maximal point (plateau) was measured before and after ezetimibe treatment.

RESULTS

Part I: Ezetimibe 10 mg daily for 3 months decreased plasma LDL-C level 16% (P = 0.002), prolonged lag time to LDL oxidation from 144 +/- 18 min to 195 +/- 16 min (P < 0.001), decreasing maximal aggregation from 83 +/- 15% to 60 +/- 36% (P = 0.04). Part II: Serum level LDL-C decreased 23% (P = 0.02) and lag time in minutes to LDL oxidation was prolonged from 55.9 +/- 16.5 to 82.7 +/- 11.6 (P < 0.0001) using combined simvastatin-ezetimibe therapy. There were no differences in platelet aggregation.

CONCLUSIONS

Ezetimibe was associated with decreased platelet aggregation and LDL tendency to peroxidation. Treatment with ezetimibe in addition to simvastatin has an additive antioxidative effect on LDL.

White blood cells telomere length is shorter in males with type 2 diabetes and microalbuminuria

OBJECTIVE

To examine differences in telomere (terminal restriction fragment [TRF]) length and pulse wave velocity (PWV)--an index of arterial stiffness--in patients with type 2 diabetes with and without microalbuminuria (MA).

RESEARCH DESIGN AND METHODS

A total of 84 men with type 2 diabetes, 40 with MA and 44 without MA (aged 63.5 +/- 9.0 vs. 61.2 +/- 9.8 years), were studied. TRF length was determined in white blood cells. MA was defined as albumin excretion rate (AER) in the range of 30-300 mg/24 h in at least two of three 24-h urine collections. PWV was assessed using applanation tonometry. Markers of oxidative stress were also measured.

RESULTS

TRF length was shorter in patients with MA than in those without MA (6.64 +/- 0.74 vs. 7.23 +/- 1.01 kb, respectively, P = 0.004). PWV was significantly higher in the patients with MA. Multivariate linear regression analysis in the total sample demonstrated an independent association between TRF length and age (P = 0.02), MA status (P = 0.04) or AER (P = 0.002), and plasma nitrotyrosine levels (P = 0.02). AER was associated significantly with PWV (P < 0.01).

CONCLUSIONS

Subjects with type 2 diabetes and MA have shorter TRF length and increased arterial stiffness than those without MA. Additionally, TRF length is associated with age, AER, and nitrosative stress. As shorter TRF length indicates older biological age, the increased arterial stiffness in patients with type 2 diabetes who have MA may be due to the more pronounced "aging " of these subjects.

Endothelial function, arterial stiffness and lipid lowering drugs

The endothelium is a dynamic organ that plays a pivotal role in cardiovascular homeostasis. Alteration in endothelial function precedes the development of atherosclerosis and contributes to its initiation, perpetuation and clinical manifestations. It has been suggested that the assessment of endothelial function could represent a barometer of vascular health that could be used to gauge cardiovascular risk. This review summarises the various methods used to assess endothelium-dependent vasodilatation and their potential prognostic implications. In addition, the techniques used to evaluate arterial stiffness are discussed. The latter is to some extent controlled by the endothelium and has been the subject of considerable research in recent years. This paper also discusses the effects of lipid lowering treatment on both endothelial function and arterial stiffness.

Ezetimibe and Simvastatin Reduce Inflammation, Disease Activity, and Aortic Stiffness and Improve Endothelial Function in Rheumatoid Arthritis

OBJECTIVES

The aim of this study was to investigate the effect of simvastatin and ezetimibe on inflammation, disease activity, endothelial dysfunction, and arterial stiffness in a cohort of rheumatoid arthritis (RA) patients.

BACKGROUND

Rheumatoid arthritis is a chronic inflammatory condition associated with increased cardiovascular risk. Statins reduce inflammation and disease activity in RA patients, but whether this is due to pleiotropism or cholesterol lowering per se is unclear.

METHODS

Twenty patients received 20 mg simvastatin or 10 mg ezetimibe each for 6 weeks in a randomized double-blind crossover study. Disease activity, blood pressure, aortic pulse wave velocity (PWV), brachial artery flow-mediated dilation (FMD), and serum inflammatory markers were measured before and after each treatment.

RESULTS

Both ezetimibe and simvastatin significantly reduced total cholesterol (-0.62 +/- 0.55 mmol/l and -1.28 +/- 0.49 mmol/l, respectively; p < 0.001), low-density lipoprotein cholesterol (-0.55 +/- 0.55 mmol/l and -1.28 +/- 0.49 mmol/l; p < 0.0001), and C-reactive protein (-5.35 +/- 9.25 mg/l and -5.05 +/- 6.30 mg/l; p < 0.001). Concomitantly, Disease Activity Score (-0.55 +/- 1.01 and -0.67 +/- 0.91; p = 0.002), aortic PWV (-0.69 +/- 1.15 m/s and -0.71 +/- 0.71 m/s; p = 0.001), and FMD (1.37 +/- 1.17% and 2.51 +/- 2.13%; p = 0.001) were significantly improved by both drugs.

CONCLUSIONS

This study demonstrates that both ezetimibe and simvastatin reduce disease activity and inflammatory markers to a similar extent in patients with RA. Therapy is also associated with a concomitant reduction in aortic PWV and improvement in endothelial function. This suggests that cholesterol lowering per se has anti-inflammatory effects and improves vascular function in RA.