Effect of cholesterol-lowering therapy on coronary endothelial vasomotor function in patients with coronary artery disease

TNF-α Predicts Endothelial Function and Number of CD34+ Cells after Stimulation with G-CSF in Patients with Advanced Heart Failure

Patients with advanced heart failure (HF) have reduced cardiac output and impaired peripheral blood flow, which diminishes endothelial shear stress and consequently flow-mediated dilatation (FMD). The aim of our study was to find out whether endothelial dysfunction is associated with the number of CD34+ cells and TNF-α levels in patients with ischemic and non-ischemic HF after stimulation with granulocyte colony-stimulating factor (G-CSF). We included 56 patients with advanced HF (LVEF < 35%). Eighteen patients (32.14%) had ischemic and 38 (67.86%) patients had non-ischemic HF. FMD of the brachial artery was performed before the patients underwent 5-day bone marrow stimulation with daily subcutaneous injections of G-CSF (5 μg/kg bid). On the fifth day peripheral blood CD34+ cell count was measured. No statistically significant differences were found between the patient groups in NT-proBNP levels ((1575 (425−2439) vs. 1273 (225−2239)) pg/mL; p = 0.40), peripheral blood CD34+ cell count ((67.54 ± 102.32 vs. 89.76 ± 71.21) × 106; p = 0.32), TNF-α ((8.72 ± 10.30 vs. 4.96 ± 6.16) ng/mL; p = 0.13) and FMD (6.7 ± 5.4 vs. 7.2 ± 5.9%; p = 0.76). In a linear regression model, only FMD (p = 0.001) and TNF-α (p = 0.003) emerged as statistically significant predictors of CD34+ cells counts. Our study suggests that TNF-α is a good predictor of impaired endothelial function and of CD34+ cells mobilization after G-CSF stimulation in patients with advanced HF of ischemic and non-ischemic origin.

Coronary Artery Disease and Endothelial Dysfunction: Novel Diagnostic and Therapeutic Approaches

Coronary artery disease is the leading cause of morbidity and mortality worldwide. The most common pathophysiologic substrate is atherosclerosis which is an inflammatory procedure that starts at childhood and develops throughout life. Endothelial dysfunction is associated with the initiation and progression of atherosclerosis and is characterized by the impaired production of nitric oxide. In general, endothelial dysfunction is linked to poor cardiovascular prognosis and different methods, both invasive and non-invasive, have been developed for its evaluation. Ultrasound evaluation of flow mediated dilatation of the branchial artery is the most commonly used method to assessed endothelial function while intracoronary administration of vasoactive agents may be also be used to test directly endothelial properties of the coronary vasculature. Endothelial dysfunction has also been the subject of therapeutic interventions. This review article summarizes the knowledge about evaluation of endothelial function in acute coronary syndromes and stable coronary artery disease and demonstrates the current therapeutic approaches against endothelial dysfunction.

Chronic inhibition of lipoprotein-associated phospholipase A2 does not improve coronary endothelial function: A prospective, randomized-controlled trial

AIMS

Lipoprotein-associated phospholipase A₂ (Lp-PLA₂), a novel biomarker for vascular inflammation, is associated with coronary endothelial dysfunction (CED) and independently predicts cardiovascular events. The current study aimed to determine whether darapladib, an orally administered Lp-PLA₂ inhibitor, improved CED.

METHODS AND RESULTS

Fifty-four patients with CED were enrolled in a double-blinded randomized placebo-controlled trial, and were randomized to receive oral darapladib, 160mg daily, or placebo. Coronary angiography and invasive coronary endothelial function assessment were performed at baseline and post-6months of treatment. Primary endpoints were change in coronary artery diameter and coronary blood flow in response to acetylcholine. Additionally, Lp-PLA₂ activity was measured at baseline and on follow-up to evaluate for adherence and drug effect. Fifty-four patients were randomized to placebo (n=29) and darapladib (n=25). Mean age in darapladib group was 55.2.±11.7years vs. 54.0±10.5years (p=0.11). On follow-up, there was no significant difference in the percent response to acetylcholine of coronary artery diameter in treatment vs. placebo group (+3 (IQR -9, 15) vs. +3 (-12, 19); p=0.87) or coronary blood flow (-5 (IQR -24, 54) vs. 39 (IQR -26, 67); p=0.41). There was significant reduction in Lp-PLA₂ activity in the treatment arm vs. placebo (-76 (IQR -113, -52) vs. -7(-21, -7); p<0.001).

DISCUSSION

Lp-PLA₂ inhibition with darapladib did not improve coronary endothelial function, despite significantly reduced Lp-PLA2 activity with darapladib. This study suggests endogenous Lp-PLA₂ may not play a primary role in coronary endothelial function in humans. CLINICALTRIALS.

GOV IDENTIFIER

NCT01067339.

Stabilization of symptomatic carotid atherosclerotic plaques by statins: a clinico-pathological analysis

Human and animal studies have revealed a stabilization of atherosclerotic plaques by statins. However, the stabilization of human carotid plaques has not been thoroughly described pathologically. This analysis explored the relationship between statin therapy and plaque stability in carotid endarterectomy (CEA) specimens. We analyzed specimens harvested between May 2015 and February 2017, from 79 consecutive patients presenting with > 70% carotid artery stenoses, of whom 66 were untreated (group 1) and 13 treated (group 2) with a statin. Immunohistochemistry was performed, using an endothelial specific antibody to CD31, CD34 and platelet derived growth factor receptor-β. The prevalence of plaque ruptures (P = 0.009), lumen thrombi (P = 0.009), inflammatory cells (P = 0.008), intraplaque hemorrhages (P = 0.030) and intraplaque microvessels (P < 0.001) was significantly lower in group 2 than in group 1. Among 66 patients presenting with strokes and infarct sizes > 1.0 cm³ on magnetic resonance imaging, the mean infarct volume was significantly smaller (P = 0.031) in group 2 (4.2 ± 2.5 cm³) than in group 1 (8.2 ± 7.1 cm³). The difference in mean concentration of low-density lipoprotein cholesterol between group 1 (121 ± 32 mg/dl) and group 2 (105 ± 37 mg/dl) was non-significant (P = 0.118). This analysis of plaques harvested from patients undergoing CEA suggests that statin therapy mitigates the plaque instability, which, in patients presenting with strokes, might decrease infarct volume.

Effect of mild endurance exercise training and pravastatin on peripheral vasodilatation of forearm resistance vessels in patients with coronary artery disease

Background Improved endothelial function may contribute to the beneficial effects of cholesterol lowering therapy in patients with coronary artery disease (CAD), but results of the effect of statin therapy on endothelial function are disparate in these patients. Exercise training has been reported to improve endothelial function of patients at risk of or with established CAD. The goal of the study was to compare the effect of mild exercise training or statin therapy on forearm endothelial function in CAD patients with average cholesterol levels.

Design and methods Twenty-eight sedentary male patients with angiographically documented CAD and average pretreatment total plasma cholesterol levels (5.1±0.9 mmol/l) aged 42–75 years were included. They were randomly assigned in a 2:1 order to either statin therapy (pravastatin, 40 mg daily) or exercise training therapy (mild endurance exercise three or more times a week). The effects of 10 weeks of either treatment on endothelium-dependent and independent vasodilation of forearm resistance vessels was assessed by plethysmography. Cardiopulmonary exercise testing was performed at baseline and after 10 weeks.

Results Ten weeks of pravastatin therapy significantly reduced low-density lipoprotein cholesterol (from 3.8±0.6 to 3.1±0.6 mmol/l at study end, P=0.04) and the ratio of total to high-density lipoprotein cholesterol (from 4.9±0.8 to 3.7±0.7 mmol/l, P=0.002). Exercise training did not significantly modify the lipid profile. Peak oxygen consumption, maximal achieved workload and exercise duration tended to improve in the exercise training group but remained unchanged in the pravastatin-treated group. Neither 10 weeks of pravastatin nor mild endurance exercise training improved endothelium-dependent or independent vasomotor function in forearm resistance vessels.

Conclusions In patients with CAD and average cholesterol levels, 10 weeks of treatment with mild endurance exercise training or with pravastatin failed to improve endothelium-dependent or independent vasomotor function in forearm resistance vessels.

Effects of Low-Dose Atorvastatin on Vascular Responses in Patients Undergoing Percutaneous Coronary Intervention With Stenting

Background: The primary endpoint of this study was to evaluate the effects of low-dose atorvastatin on carotid intima-media thickness (IMT) and endothelial function, and the secondary endpoint comprised restenosis and target lesion revascularization (TLR) in patients undergoing percutaneous coronary intervention (PCI) with stenting for the treatment of coronary artery disease.

Methods: Two hundred five consecutive patients (mean age, 60 years) undergoing PCI were prospectively randomized to usual therapy (control group, n = 100) or to 10 mg of atorvastatin daily plus usual therapy (statin group, n = 105). Carotid IMT, endothelial function (flow-mediated dilatation [FMD] of the brachial artery), and coronary angiograms were taken before the study and 6 months after randomization. The 6-month follow-up measurements of the above factors were obtained in 83 patients (83%) of the control group and in 97 patients (92%) of the statin group.

Results: No significant differences were noted in the baseline clinical and angiographic findings in either group. FMD was significantly improved during the 6 months in the statin group (4.38% ± 1.7% vs 4.85% ± 1.6%, P = .003), but did not change in the control group. Carotid IMT did not show any significant changes at 6 months in either group. There was a trend in favor of statin in terms of restenosis rate (26.8% vs 36.1%, P = .177) and TLR rate (18.6% vs 25.3%, P = .274). The changes of FMD were significantly correlated with the changes of total cholesterol and the changes of low-density lipoprotein, respectively ( r= -0.336, P = .009, and r = -0.310, P = .046).

Conclusion: Low-dose atorvastatin reduces endothelial dysfunction as measured by FMD, which coincides with the beneficial effects on lipid profiles, and can decrease restenosis and TLR rate in patients undergoing PCI with stenting.

Treating coronary disease and the impact of endothelial dysfunction

Ischemic heart disease is the leading cause of morbidity and mortality throughout the world. Many clinical trials have suggested that lifestyle and pharmacologic interventions are effective in attenuating atherosclerotic disease progression and events development. However, an individualized approach with careful consideration to comprehensive vascular health is necessary to perform successful intervention strategies. Endothelial dysfunction plays a pivotal role in the early stage of atherosclerosis and is also associated with plaque progression and occurrence of atherosclerotic complications. The assessment of endothelial function provides us with important information about individual patient risk, progress and vulnerability of disease, and guidance of therapy. Thus, the application of endothelial function assessment might enable clinicians to innovate ideal individualized medicine. In this review, we summarize the current knowledge on the impact of pharmacological therapies for atherosclerotic cardiovascular disease on endothelial dysfunction, and argue for the utility of non-invasive assessment of endothelial function aiming at individualized medicine.

Effect of statins on endothelial function in patients with acute coronary syndrome: a prospective study using adhesion molecules and flow-mediated dilatation

Background

Accumulating evidence suggests that inflammatory mechanisms play a central role in the development, progression and outcome of atherosclerosis. Recent evidence suggests that statins improve anti-inflammatory, anti-thrombotic and endothelial functions, along with their lipid-decreasing effects. We examined the effect of statins on endothelial function using biochemical markers of endothelial dysfunction and brachial artery flow-mediated dilatation (FMD).

Methods

Thirty male patients presenting with acute coronary syndrome (ACS) and 26 age-matched healthy control subjects aged 40 - 60 years who were not on any medication were enrolled in the study. The patient group was started on atorvastatin (40 mg/day) without consideration of their low-density lipoprotein (LDL)-cholesterol levels. Endothelin, sICAM and E-selectin from stored serum samples were measured using commercially available enzyme-linked immunosorbant assays (ELISAs). Endothelial function was assessed using brachial artery FMD.

Results

Prior to statin treatment, E-selectin, sICAM and endothelin levels, endothelial dysfunction markers, were 99.74 ± 34.67 ng/mL, 568.8 ± 149.0 ng/mL and 0.62 ± 0.33 fmol/mL, respectively in the patient group. E-selectin and sICAM levels were significantly higher in the patients than in the control subjects (P < 0.001); however, endothelin levels were not significantly different between groups. Statin treatment significantly reduced E-selectin and sICAM levels (P < 0.001); however, the decrease in endothelin levels was not statistically significant. %FMD values were significantly increased after statin treatment (P = 0.005), and levels of C-reactive protein (CRP), an inflammation marker, were significantly reduced.

Conclusion

Our results indicate that statins play an important role in treatment endothelial dysfunction by reducing adhesion of inflammatory cells.

Targeting the unstable plaque in acute coronary syndromes

BACKGROUND

Rupture or erosion of an unstable atherosclerotic plaque is the typical pathology and usual cause of acute coronary syndromes. Despite detailed understanding of the processes of lipid accumulation, thinning of the fibrous cap, and inflammation leading to plaque instability, there are no strategies in clinical use that uniquely target the unstable plaque.

OBJECTIVE

A critical review of recent publications on potential therapies that could be used to stabilize unstable plaque.

METHODS

We searched PubMed, other literature databases, drug development sites, and clinical trial registries to retrieve clinical studies on anti-inflammatory and lipid-modulating therapies that could be used to stabilize unstable atherosclerotic plaque.

RESULTS

Multiple experimental targets involving lipid and inflammatory pathways have the potential to stabilize the plaque and expand the armamentarium against coronary artery disease. Randomized clinical trials of darapladib, methotrexate, canakinumab, and colchicine are well advanced to establish if plaque stabilization is feasible and effective in patients with acute coronary syndromes.

CONCLUSIONS

Although there are still no agents in clinical use for plaque stabilization, there are important advances in understanding plaque instability and several encouraging approaches are being evaluated in Phase III clinical trials.

Impact of atorvastatin treatment in first-degree relatives of patients with premature coronary artery disease with endothelial dysfunction: a double-blind, randomized, placebo-controlled crossover trial

BACKGROUND

A family history of premature coronary artery disease (CAD) is a well-known risk factor for cardiovascular events.

HYPOTHESIS

Atorvastatin may improve endothelial dysfunction (ED) in the first-degree relatives (FDRs) of patients with premature CAD with ED.

METHODS

Thirty-five FDRs (median age, 52 years [interquartile range (IQR), 46-57 years], 21 male) of patients with premature CAD with ED were recruited in a prospective trial with a crossover double-blind design: 6 weeks of treatment with atorvastatin 40 mg/day followed by placebo, or vice versa. After each treatment, the digital pulse wave amplitude was determined by EndoPAT to obtain the reactive hyperemia index (RHI), a measure for endothelial function. The primary outcome was the difference of RHI between atorvastatin and placebo treatment.

RESULTS

Low-density lipoprotein cholesterol was lower after atorvastatin compared with placebo treatment (124 [102-145] mg/dL vs 67 [50-73] mg/dL, P < 0.001). However, RHI was not different after atorvastatin compared with placebo treatment (1.9 [1.5-2.4] vs 1.9 [1.6-2.2], P = 0.902). Also, the augmentation index was similar after each treatment. These results were observed both in subjects who had indications for statin treatment (31%) and those who did not (69%) according to National Cholesterol Education Program Adult Treatment Panel III guidelines.

CONCLUSIONS

Despite improvement in the lipid profile, atorvastatin failed to improve ED in the FDRs of patients with premature CAD with ED. Although we identified those with ED in FDRs of patients with premature CAD as a high-risk group for future cardiovascular events, atorvastatin treatment may not be a beneficial primary prevention strategy for this population.

Endothelial function as a functional expression of cardiovascular risk factors

Traditional cardiovascular risk (CV) factors based on the Framingham study have been used to estimate the risk of CV events and determine target cholesterol levels for primary prevention. Recently published systematic reviews have, however, demonstrated that the Framingham risk score is limited in certain cohorts and requires adjustment. Indeed, traditional CV risk factors fail to predict the development of coronary heart disease in 25-50% of cases. This underscores the complex interplay between traditional CV risk factors, genetic predisposition and other atheroprotective factors present in individuals of different populations in predicting CV events. Endothelial dysfunction, a functional expression of the inherent atherosclerotic risk representing an integrated index of both the overall CV risk-factor burden and the sum of all vasculoprotective factors in an individual, may serve as the missing link between CV risk factors and atherosclerotic disease. Endothelial function measurements may aid in future prediction of CV events and help identify high-risk patients for targeted therapy as well as provide a primary therapeutic end point for clinical follow-up of these patients. Recently introduced reactive hyperemia peripheral arterial tonometry is emerging as a promising tool in endothelial function measurement and CV risk stratification.

A randomized placebo-controlled study on the effect of nifedipine on coronary endothelial function and plaque formation in patients with coronary artery disease: the ENCORE II study

AIMS

Endothelial dysfunction and plaque formation are features of atherosclerosis. Inhibition of L-type calcium channels or HMG-CoA pathway improves endothelial function and reduces plaque size. Thus, we investigated in stable coronary artery disease (CAD) the effects of a calcium antagonist on coronary endothelial function and plaque size.

METHODS AND RESULTS

In 454 patients undergoing PCI, acetylcholine (10(-6) to 10(-4) M) was infused in a coronary segment without significant CAD. Changes in coronary diameter were measured and an intravascular ultrasound examination (IVUS) was performed. On top of statin therapy, patients were randomized in a double-blind fashion to placebo or nifedipine GITS 30-60 mg/day and followed for 18-24 months. Blood pressure was lower on nifedipine than on placebo by 5.8/2.1 mmHg (P < 0.001) as was total and LDL cholesterol (4.8 mg/dL; P = 0.495), while HDL was higher (3.6 mg/dL; P = 0.026). In the most constricting segment, nifedipine reduced vasoconstriction to acetylcholine (14.0% vs. placebo 7.7%; P < 0.0088). The percentage change in plaque volume with nifedipine and placebo, respectively, was 1.0 and 1.9%, ns.

CONCLUSION

The ENCORE II trial demonstrates in a multi-centre setting that calcium channel blockade with nifedipine for up to 2 years improves coronary endothelial function on top of statin treatment, but did not show an effect of nifedipine on plaque volume.

Endothelial dysfunction and cardiovascular risk factors

The endothelium plays an integral role in the regulation of vascular tone, platelet activity, leukocyte adhesion, and thrombosis and is intimately involved in the development of atherosclerosis. Endothelial dysfunction has been observed in patients with established coronary artery disease or coronary risk factors, both in the coronary and peripheral vasculature. Therapeutic interventions with lipid-lowering drugs, ACE inhibitors, physical activity, and antioxidant agents have been shown to improve endothelial function in coronary and peripheral vessels. This systemic manifestation and improvement of endothelial function suggests that a common mechanism may contribute to endothelial dysfunction in the coronary and peripheral circulation.

TARGET AUDIENCE

Internist, Cardiologists, Family physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to define the participation of cardiovascular risk factors in the various complications associated with endothelial dysfunction.

Flow-mediated dilation in patients with coronary artery disease is enhanced by high dose atorvastatin compared to combined low dose atorvastatin and ezetimibe: results of the CEZAR study

BACKGROUND

Effects independent from cholesterol reduction on vascular function are considered to importantly contribute to the beneficial effects of statin therapy in cardiovascular disease. We aimed to evaluate the effect of high versus low dose atorvastatin on endothelial dysfunction in patients with coronary artery disease (CAD) in a setting of comparable cholesterol reduction.

METHODS AND RESULTS

Fifty-eight patients with CAD were randomly assigned to double-blind treatment for 8 weeks with atorvastatin 80 mg per day (A80) or atorvastatin 10mg+ezetimibe 10mg per day (A10E10), respectively. Flow-mediated vasodilation (FMD) of the brachial artery, nitroglycerin-mediated endothelium-independent vasodilation (NMD), lipid, C-reactive protein (CRP) plasma concentrations and urinary 8-iso-prostaglandin F2alpha excretion were measured before and after treatment. Total cholesterol, triglycerides and LDL-cholesterol levels were significantly reduced with no difference between A80 and A10E10. A80 caused significantly stronger improvement of FMD compared to A10E10 (absolute change FMD: A80+2.7+/-3.0% (post vs. pre p<0.001), A10E10+0.6+/-2.9% (post vs. pre p=0.25), A80 vs. A10E10 p=0.018). NMD was improved by A80 but not by A10E10 (absolute change NMD: A80+2.7+/-4.6%, A10E10+0.7+/-3.5%, p=0.12). Both treatment groups caused a comparable reduction of CRP and did not effect urinary 8-iso-prostaglandin F2alpha excretion. There was no correlation between FMD or NMD change and LDL-cholesterol change in either treatment group.

CONCLUSIONS

The present findings clearly suggest that in the presence of comparable LDL-lowering effects of both treatment forms, LDL-cholesterol independent effects of high dose atorvastatin therapy account for the improvement of endothelium-dependent vasodilation in patients with stable CAD.

Effects of a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, fluvastatin, on coronary spasm after withdrawal of calcium-channel blockers

OBJECTIVES

The purpose of this study was to determine whether a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) suppresses coronary spasm.

BACKGROUND

Coronary spasm is associated with endothelial dysfunction. Statins have been shown to improve endothelial function.

METHODS

This was a prospective, randomized, open-label, end point study. Sixty-four patients who had no significant organic coronary stenosis and in whom coronary spasm was induced by intracoronary injection of acetylcholine (ACh) were randomly assigned to fluvastatin 30 mg/day plus the conventional calcium-channel blocker (CCB) therapy (31 patients, statin group) or the conventional CCB therapy (33 patients, nonstatin group). After 6 months of treatment, the intracoronary injection of ACh was repeated and the coronary spasm was assessed.

RESULTS

Coronary spasm was suppressed in 16 of the 31 patients (51.5%, p < 0.0001) of the statin group and in 7 of the 33 patients (21.2%, p = 0.0110) of the nonstatin group after 6 months of treatment. Thus, the number of patients with ACh-induced coronary spasm was significantly reduced in the statin group as compared with the nonstatin group (51.6% vs. 21.2%, p = 0.0231) after 6 months of treatment.

CONCLUSIONS

The addition of fluvastatin 30 mg/day to the conventional CCB therapy for 6 months significantly reduced the number of patients with ACh-induced coronary spasm as compared with the conventional CCB therapy. Thus, a statin (fluvastatin) may possibly be a novel therapeutic drug for coronary spasm.

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.

Asymmetric Dimethylarginine Determines the Improvement of Endothelium-Dependent Vasodilation by Simvastatin

OBJECTIVES

We hypothesized that the level of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of endothelial nitric oxide (NO) synthase (eNOS), might determine the endothelial effects of statins.

BACKGROUND

Endothelial NO synthase is up-regulated by statins. However, statins failed to improve endothelial function in some studies. Asymmetric dimethylarginine inhibits eNOS by a mechanism that is reversible by L-arginine.

METHODS

Ninety-eight clinically asymptomatic elderly subjects had their plasma ADMA levels screened. Those in the highest (high ADMA, n = 15) and lowest quartiles of the ADMA distribution (low ADMA, n = 13) were eligible to receive, in a randomized order, simvastatin (40 mg/day), L-arginine (3 g/day), or a combination of both, each for 3 weeks. Endothelium-dependent vasodilation (EDD) was assessed by brachial artery ultrasound.

RESULTS

Simvastatin had no effect on EDD in subjects with high ADMA (6.2 +/- 1.2% vs. 6.1 +/- 0.9%), whereas simvastatin plus L-arginine significantly improved EDD (9.8 +/- 1.5% vs. 5.3 +/- 0.8%; p < 0.01). In subjects with low ADMA, simvastatin improved endothelial function when given alone (9.5 +/- 3.2% vs. 6.1 +/- 3.8%; p < 0.001) or in combination with L-arginine (9.0 +/- 3.1% vs. 6.3 +/- 3.3%; p = 0.001). L-arginine alone improved endothelial function in both groups. Endothelium-independent vasodilation was not affected.

CONCLUSIONS

Simvastatin does not enhance endothelial function in subjects with elevated ADMA, whereas it does so in patients with low ADMA. Combination of simvastatin with oral L-arginine improves endothelial function in subjects with high ADMA, but has no additional effect in subjects with low ADMA. As NO-mediated effects may play a major role in the therapeutic effects of statins, ADMA concentration is an important factor that influences the "pleiotropic" effects of simvastatin.

Impaired endothelial vasomotor function after sirolimus-eluting stent implantation

BACKGROUND

Sirolimus inhibits endothelial cell proliferation in vitro, but although the sirolimus-eluting stent (SES) is widely used because of the very low rates of in-stent restenosis, the influence of SES on coronary endothelial vasomotor function in humans is not well known.

METHODS AND RESULTS

The present study included 21 patients treated with SES, and 12 patients treated with conventional bare metal stent (BMS). Endothelium-dependent vasomotor function was evaluated 6 months after stent implantation, using intracoronary acetylcholine infusion. Changes in diameter at the 5-mm proximal and distal edges of the stent, and at the control segment were assessed by quantitative coronary angiography. To evaluate native endothelial function, an intracoronary acetylcholine test was performed before stenting. In the 21 SES patients acetylcholine infusion at 10(-8) mol/L and 10(-7) mol/L produced significant vasoconstriction in the proximal stent segment (-11.3+/-10.3%, and -14.1+/-11.3%, respectively) and the distal stent segment (-13.7+/-9.3%, and -17.5+/-12.5%, respectively). In contrast, in the 12 BMS patients, acetylcholine infusion at the same concentrations did not produce a vasoconstrictive response in the proximal stent segment (5.0+/-8.2% and 4.9+/-9.1%, respectively) or the distal stent segment (4.2+/-7.6% and 5.1+/-7.7%, respectively). Intracoronary nitroglycerin induced a similar grade of vasodilation in the peri-stent area in both groups. Local endothelial function before SES implantation showed no vasoconstrictive response.

CONCLUSIONS

In contrast to vasodilation in BMS patients, SES implantation in the peri-stent area resulted in a vasoconstrictive response to acetylcholine. SES implantation may impair endothelial function in humans.

Asymmetrical dimethylarginine (ADMA) and coronary endothelial function in patients with coronary artery disease and mild hypercholesterolemia

OBJECTIVE

To investigate the association of the endogenous nitric oxide synthase inhibitor asymmetrical dimethylarginine (ADMA) and coronary endothelial function.

METHODS AND RESULTS

In 289 patients with coronary artery disease we assessed coronary endothelium-dependent and -independent vascular responses to intracoronary infusion of acetylcholine, adenosine, and nitroglycerin, respectively, and determined plasma ADMA and l-arginine concentrations by HPLC. After 6 months of treatment with either cerivastatin, nifedipine, cerivastatin+nifedipine, or placebo, coronary vascular function testing as well as ADMA and l-arginine determinations were repeated. We observed no correlation of plasma ADMA or l-arginine concentration and coronary response to acetylcholine, adenosine or nitroglycerin baseline, and no correlation of changes of ADMA or l-arginine plasma concentration with changes in coronary function (all r and rho<0.3, all p>0.05).

CONCLUSION

At physiological plasma concentrations ADMA appears to have only little impact on coronary endothelial function.

High-dose atorvastatin is associated with impaired myocardial angiogenesis in response to vascular endothelial growth factor in hypercholesterolemic swine

OBJECTIVES

The disappointing results of myocardial angiogenic therapy have been attributed, in part, to endothelial dysfunction present in patients with coronary disease. Statins have established proendothelial properties but seem to have dose-dependent effects on angiogenesis. We investigated the functional and molecular effects of high-dose atorvastatin on vascular endothelial growth factor-induced myocardial angiogenesis in hypercholesterolemic swine.

METHODS

Yucatan miniswine (20-30 kg) were fed either a normal (ND group, n = 8) or high-cholesterol diet, with (HC-ATOR group, n = 8) or without (HC group, n = 8) atorvastatin (3 mg x kg(-1) x d(-1)), for 13 weeks. Chronic ischemia was induced by ameroid constrictor placement around the circumflex artery, followed 3 weeks later by perivascular vascular endothelial growth factor administration (2 microg over 4 weeks) with a sustained release osmotic pump. Microvessel relaxation responses, myocardial perfusion, and myocardial expression of angiogenic mediators were assessed 4 weeks later.

RESULTS

Hypercholesterolemic swine demonstrated impaired microvessel relaxation to vascular endothelial growth factor (P < .01 vs ND group) and adenosine diphosphate (P < .001 vs ND group), which was normalized in the HC-ATOR group. After perivascular vascular endothelial growth factor administration, collateral-dependent myocardial perfusion was significantly increased in the ND group but decreased in both the HC and HC-ATOR groups (both P < .01 vs the ND group). The animals in the HC-ATOR group demonstrated increased myocardial expression of the antiangiogenic protein endostatin and increased Akt phosphorylation without significant changes in Akt and endothelial nitric oxide synthase expression.

CONCLUSIONS

Atorvastatin treatment reverses hypercholesterolemia-induced endothelial dysfunction without appreciable improvements in collateral-dependent myocardial perfusion in response to vascular endothelial growth factor treatment. Increased myocardial endostatin expression and chronic Akt activation, associated with atorvastatin therapy, might account for the lack of improvement in the angiogenic response to vascular endothelial growth factor therapy.

Linking C-reactive protein to late-life disability in the National Health and Nutrition Examination Survey (NHANES) 1999-2002

BACKGROUND

Chronic inflammation, measured by interleukin-6, predicts incident disability among elderly people. However, little is known about the relation of C-reactive protein (CRP) to disability.

METHOD

Participants (>60 years old, N = 1680) were from the National Health and Nutrition Examination Survey 1999-2002. Disability in activities of daily living (ADL), instrumental activities of daily living (IADL), leisure and social activities (LSA), lower extremity mobility (LEM), and general physical activities (GPA) was obtained by self-report. Peak muscle power was the product of isokinetic peak leg torque and peak force velocity. Functional limitations were evaluated via habitual walking speed, which was obtained from a 20-foot timed walk. CRP levels were quantified by using latex-enhanced nephelometry.

RESULTS

Elevated CRP levels were associated with disability in IADL, LSA, LEM, and GPA, independent of basic demographics, chronic medical diseases, health behaviors, as well as nutritional markers. The corresponding odds ratios of disability for each standard-deviation increase in natural-log-transformed CRP were 1.18 (95% confidence interval [CI], 1.02-1.35), 1.18 (95% CI, 1.00-1.39), 1.17 (95% CI, 1.03-1.33), and 1.17 (95% CI, 1.05-1.31), respectively. The relationship diminished after additional adjustment of leg power and/or walking speed, meaning that impairment in leg power and limitations in gait speed likely mediate the association between CRP and disability. CRP had an inverse relationship to leg power and walking speed. Likewise, additional adjustment for leg power substantially diminished the association between CRP and walking speed, suggesting a mediating effect of power between CRP and gait speed.

CONCLUSIONS

Independent of chronic diseases, elevated CRP is associated with multiple domains of disability through mediation of muscle power, habitual gait speed, or both. Future research is needed to understand CRP as a risk factor for disability in older populations.

Myocardial flow reserve is influenced by both coronary artery stenosis severity and coronary risk factors in patients with suspected coronary artery disease

PURPOSE

Myocardial flow reserve (MFR) measurement has an important role in assessing the functional severity of coronary artery stenosis. However, a discrepancy between the anatomical severity of coronary artery stenosis and MFR is often observed. Such a discrepancy may be explained by coronary risk factors. In this study, we aimed to investigate the influence of coronary artery stenosis severity and risk factors on MFR.

METHODS

Seventy-four patients suspected to have coronary artery disease and seven age-matched healthy volunteers were enrolled. Myocardial blood flow (MBF) and MFR were measured using 15O-labelled water PET. Regional MFR was calculated in regions with significant coronary artery stenosis (stenotic regions) and in regions without significant stenosis (remote regions). The contributions of coronary artery stenosis severity and coronary risk factors were assessed using univariate and multivariate analyses.

RESULTS

In stenotic regions, MFR correlated inversely with coronary artery stenosis severity (r=-0.50, p<0.01). Univariate analysis did not show any significant difference in MFR between the patients with and the patients without each risk factor. In remote regions, however, MFR was significantly decreased in the diabetes and smoking groups (each p<0.05). By multivariate analysis, diabetes and smoking were independent predictors of MFR (each p<0.05). In the group with more than one risk factor, MFR was significantly lower (2.78+/-0.79) than in the other group (3.40+/-1.22, p<0.05).

CONCLUSION

MFR is influenced not only by coronary stenosis severity but also by coronary risk factors. In particular, the influence of risk factors should be considered in regions without severe coronary stenosis.

Effect of pravastatin on blood pressure in people with cardiovascular disease

Experimental evidence and several small studies in humans suggest that HMG-CoA (3-hydroxy 3-methylglutaryl coenzyme A) reductase inhibitors (statins) reduce blood pressure, perhaps through effects on endothelial function or by reducing inflammation. We tested the hypothesis that pravastatin would reduce blood pressure at 3 months and the risk of developing new hypertension over a follow-up period of 5 years. This was a post hoc subgroup analysis of a randomized double-blind placebo-controlled trial of pravastatin 40 mg daily vs placebo in 4159 participants with previous myocardial infarction and total plasma cholesterol <240 mg/dl (6.2 mmol/l). The primary outcome was the unadjusted change in mean arterial pressure (MAP) from baseline to 3 months. We also considered systolic and diastolic blood pressure (SBP and DBP) and pulse pressure. Analysis of covariance was used to calculate the adjusted effect of treatment on change in these outcomes at 3, 6, 12 and 24 months postrandomization, after controlling for potential confounders. Logistic regression was used to calculate the adjusted effect of treatment on incident hypertension (blood pressure > or =140/90 in those without known hypertension at baseline). This analysis included 4126/4159 (99.2%) participants for whom blood pressure was measured at baseline and during at least one follow-up visit. Median duration of follow-up was 57.8 months. The unadjusted and adjusted change in MAP, SBP, DBP or pulse pressure from baseline was not significantly different for pravastatin or placebo recipients at 3, 6, 12 or 24 months after randomization, or at last follow-up. Pravastatin did not reduce the adjusted risk of incident systolic hypertension (odds ratio 0.99, 95% CI 0.80-1.23), or incident diastolic hypertension (odds ratio 0.97, 95% CI 0.73-1.27). In summary, pravastatin 40 mg daily did not reduce blood pressure in survivors of myocardial infarction without overt hypercholesterolaemia.

Differential effects of short-term lipid lowering with ezetimibe and statins on endothelial function in patients with CAD: clinical evidence for 'pleiotropic' functions of statin therapy

AIMS

Statin therapy is associated with improved endothelial vasodilator function. The clinical availability of ezetimibe, a potent novel cholesterol absorption inhibitor, enables to differentiate lipid-lowering effects from potential non-lipid-lowering (pleiotropic) mechanisms of statins.

METHODS AND RESULTS

Forearm blood flow (FBF) responses to acetylcholine (ACH) and sodium nitroprusside (SNP) were measured by venous occlusion plethysmography in four prospectively defined groups of patients with stable coronary artery disease (CAD) before and after 4 weeks of lipid-lowering therapy. Group A (n=15): de novo monotherapy with 10 mg/day ezetimibe; Group B (n=15): 10 mg/day ezetimibe as an add-on to chronic simvastatin therapy with 20 mg/day; Group C (n=15): dose escalation from chronic 10 to 40 mg/day atorvastatin; and Group D (n=15): de novo monotherapy with 40 mg/day atorvastatin. After 4 weeks of therapy, LDL cholesterol levels were significantly reduced in all four groups. Neither ezetimibe monotherapy (Group A) nor ezetimibe combined with 20 mg simvastatin (Group B) was associated with an increase in ACH-mediated FBF responses after 4 weeks. In contrast, dose escalation of atorvastatin from 10 to 40 mg/day (Group C) or de novo therapy with 40 mg atorvastatin/day (Group D) was associated with a significant increase in ACH-mediated FBF responses (P<0.013).

CONCLUSION

Thus, both statins and ezetimibe effectively lower LDL-levels within 4 weeks of therapy. However, only statin therapy is associated with improved endothelial vasodilator function, disclosing the relevance of pleiotropic effects of statins during short-term treatment of patients with CAD.

Impact of Coronary Endothelial Function on the Progression of Cardiac Transplant–associated Arteriosclerosis: Effect of Anti-oxidant Vitamins C and E

BACKGROUND

Excessive vascular oxidant stress has been implicated in cardiac transplant-associated arteriosclerosis (TxAA). In a recent placebo-controlled study of 40 cardiac transplant recipients, vitamin C 500 mg twice a day and vitamin E 400 IU twice a day for 1 year retarded the progression of TxAA, as assessed by intravascular ultrasound (IVUS). Endothelial dysfunction is a key feature of TxAA and reflects oxidant stress. We hypothesized that coronary endothelial dysfunction portends greater TxAA progression and a larger therapeutic response to anti-oxidant vitamins.

METHODS

In this pre-specified analysis, the 40 cardiac transplant recipients were categorized according to normal or abnormal coronary endothelial vasomotor function at baseline, as assessed by acetylcholine (10(-8) to 10(-6) mol/liter). The effect of anti-oxidant vitamins within these two groups of patients was assessed by the change in intimal index over 1 year using IVUS.

RESULTS

With placebo (n = 21), the increase in intimal index was greater in the presence vs absence of endothelial dysfunction (11 +/- 3% vs 5 +/- 1%, p < 0.05). Among patients with endothelial dysfunction (n = 21), the intimal index increased 11 +/- 3% with placebo, but decreased -1 +/- 2% with vitamins (p = 0.002). Among patients with normal endothelial function (n = 14), the intimal index increased 5 +/- 1% with placebo and 1 +/- 1% with vitamins (p < 0.05).

CONCLUSIONS

Endothelial dysfunction indicates rapid TxAA progression, even in the statin era. Although anti-oxidant vitamins reduce disease progression in patients with normal or abnormal endothelial function, the magnitude of benefit is larger in patients with endothelial dysfunction.

Short- and long-term influence of diet and simvastatin on brachial artery endothelial function

BACKGROUND

Endothelium-dependent dilation (EDD) has often been studied in patients with hypercholesterolemia without overt coronary atherosclerosis where an improvement after statin treatment has been documented within few weeks. The aim of the study was to assess the short-term effect of diet as well as short- and long-term effect of simvastatin on EDD in patients with hypercholesterolemia and ischemic heart disease.

METHODS

In 43 male patients with hypercholesterolemia and ischemic heart disease, EDD of the brachial artery was measured at baseline, after 3 months on a lipid-lowering diet, and after another 1, 3 and 12 months on simvastatin at 40 mg/day.

RESULTS

Three months changes in EDD were neither influenced by diet nor short-term simvastatin therapy (4.9% vs. 4.9% vs. 4.8%, p=ns). Twelve months simvastatin treatment, however, significantly improved EDD by 32.7% (4.9% vs. 6.5%, p=0.007). By regression analysis an individual adjusted increase in EDD during the simvastatin treatment period was seen (coefficient 0.132 a month, p=0.002). A significant reduction in total cholesterol of 31.0% (6.1+/-0.8 vs. 4.2+/-0.7, p<0.001) and LDL cholesterol of 42.6% (4.0+/-0.8 vs. 2.2+/-0.6, p<0.001) was observed.

CONCLUSION

EDD is improved after long-term simvastatin therapy; however, neither did 3 months diet or 3 months simvastatin therapy has influence on the EDD.

Effect of simvastatin on coronary flow reserve in patients with atherosclerosis and hypercholesterolemia: an intracoronary Doppler study

BACKGROUND

Early stages of coronary atherosclerosis are accompanied by a functional impairment of coronary vasodilator capacity and endothelial dysfunction. Reduced coronary flow reserve has been reported in patients with hypercholesterolemia, despite angiographically normal coronary arteries. The aim of the study was to evaluate the effect of simvastatin on coronary flow reserve.

METHODS

The study was an open non-placebo-controlled serial investigation in which every patient acted as his own control: 36 male patients with hypercholesterolemia and a non-significant coronary artery lesion in a not previously revascularized coronary artery. Intracoronary Doppler measurements were performed. Coronary flow reserve, relative coronary flow reserve and average peak velocity were performed at baseline, after 3 months on a lipid-lowering diet (control period), and after another 12 months of simvastatin 40 mg/day. In the same patient cohort, significant reduction in lesion plaque plus media has been demonstrated by intravascular ultrasound.

RESULTS

Changes in coronary flow reserve were not influenced by either diet or simvastatin (2.5+/-0.6 vs. 2.6+/-0.5 vs. 2.6+/-0.6, P=ns). Maximum hyperemic flow (34.8+/-12.2 vs. 36.7+/-12.5 vs. 42.5+/-13.1, P<0.001) as well as resting flow (14.3+/-5.3 vs. 14.5+/-4.4 vs. 16.6+/-4.6, P<0.001) increased significantly after 12 months simvastatin therapy.

CONCLUSION

Despite plaque plus media, regression simvastatin therapy for 12 months does not affect coronary flow reserve obtained using serial intracoronary Doppler studies. Simvastatin, however, increases the hyperemic flow velocity.

The effects of HMG-CoA reductase inhibitors on endothelial function

Vascular endothelial dysfunction is a complex phenomenon that is caused by an imbalance of vasodilator and vasoconstrictor factors that regulate the equilibrium-maintaining vascular tone. In the early phase of hypercholesterolemia, endothelial dysfunction precedes vascular wall lesions. One of the earliest recognizable benefits of treatment with HMG-CoA reductase inhibitors (statins) is the normalization of endothelium-dependent relaxation in hypercholesterolemia; this effect occurs before significant lowering of serum cholesterol levels. Recent insights into cellular mechanisms indicate that statins promote vasorelaxation by upregulating the expression of endothelial nitric oxide (NO) synthase, activating the phosphatidylinositide 3-kinase/Akt pathway, inhibiting superoxide anion generation and endothelin synthesis, and by anti-inflammatory effects. These effects appear to be linked to the inhibition of geranylgeranylation of small G proteins such as Rho and Rac GTPases. In this regard, statins preserve endothelial function through the improvement of NO bioavailability and the reduction of oxidative stress, thereby shifting the balance from vasoconstriction to vasodilation. This review highlights the various mechanisms underlying the vasculoprotective effects of statins, independent of their effects on cholesterol lowering.

Relationship between endothelial function in the coronary and brachial arteries

BACKGROUND

Endothelial dysfunction is the first step in the progression to atherosclerosis, but little is known regarding whether there is a correlation in endothelial function between the coronary and peripheral arteries.

HYPOTHESIS

We investigated the relationship between coronary and peripheral endothelial function.

METHODS

In 41 patients (mean age 63 years; 23 men, 18 women) with angiographically normal coronary arteries, changes in brachial artery diameter in response to hyperemic flow and sublingual nitroglycerin (NTG) were measured by high-resolution ultrasonography. During coronary angiography, acetylcholine (ACh, 3 and 30 microg/min) and NTG were infused into the left coronary ostium. The diameter of the coronary artery was quantitatively measured and coronary blood flow (CBF) was calculated by quantitative angiography and Doppler flow velocity measurements. Changes in these parameters in response to each drug infusion were expressed as the percent change from the baseline values.

RESULTS

Flow-mediated dilation (FMD) of the brachial artery was 5.0 +/- 3.5% and correlated positively not only with the change in coronary diameter (ACh at 30 microg/min, r = 0.31, p < 0.05) but also with the change in CBF (ACh at 3 microg/min, r = 0.39, p < 0.05; ACh at 30 microg/min, r = 0.46, p < 0.01). Multivariate analysis demonstrated that FMD was one of the factors associated with the changes in coronary diameter and CBF.

CONCLUSIONS

These results suggest that brachial endothelial function is associated with coronary endothelial function in patients with angiographically normal coronary arteries, suggesting that impairment of endothelial function may occur simultaneously in both coronary and peripheral arteries.

Fluvastatin and lovastatin but not pravastatin induce neuroglial differentiation in human mesenchymal stem cells

Recent studies have shown that statins, the most potent inhibitors of 3-hydroxy-2-methylglutaryl coenzyme A (HMG-CoA) reductase, stimulate bone formation in vitro and in rodents by activating the expression of bone morphogenetic protein-2 (BMP-2), one of the most critical osteoblast differentiation-inducing factors. However, the effect of statins on mesenchymal stem cells (MSCs) is yet to be reported. The purpose of this study is to investigate the influence of fluvastatin, lovastatin, and pravastatin, three commonly prescribed lipid-lowering agents, on the proliferation and differentiation of human MSCs. To our surprise, even though fluvastatin and lovastatin effectively suppressed the growth of human MSCs, a neuroglia rather than osteoblast-like morphology was observed after treatment. Interestingly, such morphological change was inhibited by the co-addition of geranylgeranyl pyrophosphate (GGPP). Immunofluorescence staining with antibodies against neuron-, astrocyte-, as well as oligodendrocyte-specific markers confirmed the neuroglial identity of the differentiated cells. However, BMP-2 is unlikely to play a positive role in neuroglial differentiation of MSCs since its expression was down-regulated in fluvastatin-treated cells. Taken together, our results suggest that fluvastatin and lovastatin induce neuroglial differentiation of human MSCs and that these cholesterol-lowering agents might be used in conjunction with MSC transplantation in the future for treating neurological disorders and injuries.

The case for intensive statin therapy after acute coronary syndromes

Acute coronary syndromes (ACS) consist of unstable angina or acute myocardial infarction and are associated with a high risk of early recurrent ischemic events. Revascularization procedures do not modify underlying pathophysiology and only modestly reduce early ischemic events after an index episode of ACS. Although statins improve dyslipidemia and cardiovascular risk over the long term, efforts to identify new ACS treatments are focusing on the ability of statins to modify the arterial wall-blood interface and reduce the risk of early recurrent ischemic events. Statins have been shown to reduce circulating markers of inflammation within days of an acute ischemic event. Short-term statin therapy also has been associated with improved coronary endothelial function, reversal of prothrombotic states, and reduction in atherosclerotic plaque volume. Findings from 6 randomized, controlled intervention trials were evaluated to determine if risk reduction is associated with the intensity of statin therapy. In addition, the predictive ability of baseline lipid levels and inflammatory markers were examined. High-intensity statin therapy (atorvastatin 80 mg) reduced early recurrent ischemic events after ACS compared with moderate-intensity treatment (eg, pravastatin 40 mg) or placebo. Moderate-intensity regimens (simvastatin 40 mg, pravastatin 20 to 40 mg, fluvastatin 80 mg, cerivastatin 0.4 mg) provided minimal benefit compared with placebo. Although there was no apparent relation between low-density lipoprotein (LDL) cholesterol levels before or during randomized treatment and short-term (4-month) risk of recurrent events, the degree of LDL cholesterol reduction with statin treatment after ACS may be related to longer-term event reduction. Moreover, evidence suggests that anti-inflammatory effects of high-intensity statin treatment are associated with clinical benefit.

Clinical impact of vasomotor function assessment and the role of ACE-inhibitors and statins

Impaired endothelial function is recognised as one of the earliest events of atherogenesis. Endothelium-dependent vasomotion has been the principal method to assess endothelial function. In this article, we will discuss the clinical value of the different techniques to evaluate endothelium-dependent vasomotion. To date, there seems not to be a simple and reliably endothelial function test to identify asymptomatic subjects at increased risk for cardiovascular disease in clinical practice. Recent studies indicate that pharmacological interventions, in particular with ACE-inhibitors and statins, might improve endothelial function. However, there is no solid evidence that improvement of endothelial function is a necessity for the observed reduction in cardiovascular events by these compounds. Overall, at this moment, there is no place in clinical practice for the use of endothelial function as a method for risk assessment or target of pharmacological interventions.

Effects of combined administration of low dose atorvastatin and vitamin E on inflammatory markers and endothelial function in patients with heart failure

BACKGROUND

Heart failure has been associated with impaired endothelial function, increased inflammatory process and elevated oxidative stress status. Both statins and vitamin E separately improve endothelial function in patients with hypercholesterolemia and/or advanced atherosclerosis.

AIM

To evaluate the effect of atorvastatin alone or in combination with vitamin E on endothelial function and serum levels of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha) and vascular cells adhesion molecule (sVCAM-1) in patients with ischemic heart failure.

METHODS

Thirty-eight male patients with ischemic cardiomyopathy were randomly divided into three groups and received either atorvastatin 10 mg/day (n = 14), a combination of atorvastatin 10 mg/day plus vitamin E 400 IU/day (n = 12), or no statin or antioxidant treatment (n=12, controls) for 4 weeks. Forearm blood flow (FBF) was measured using venous occlusion strain-gauge plethysmography. Forearm vasodilatory response to reactive hyperemia (RH%) or to nitrate (NTG%) was defined as the percent change of FBF from rest to the maximum flow during reactive hyperemia or after nitrate administration, respectively.

RESULTS

RH% was significantly improved in both the atorvastatin-treated (p < 0.01) and atorvastatin plus vitamin E groups (p < 0.05), but the increase was significantly higher in the atorvastatin-treated group (p < 0.05). Serum levels of IL-6, TNF-alpha and sVCAM-1 were decreased in the atorvastatin-treated group (p < 0.05 for all), but remained unaffected in the other two groups (p = NS for all).

CONCLUSIONS

Low dose atorvastatin treatment improves endothelial function and reduces the expression of proinflammatory cytokines and adhesion molecules in patients with ischemic heart failure, an effect partly depressed by vitamin E.

Cardiovascular risk factor profiles and endothelial function in coronary artery disease patients treated with statins

Although endothelial dysfunction is associated with cardiovascular risk factors and is improved by cholesterol-lowering therapy, the relationship between endothelial function and cardiovascular risk factor profiles has not been fully investigated in coronary artery disease patients who have been treated with statins. We investigated endothelial function in male hypercholesterolemic patients (n=53) who underwent statin therapy over 6 months in a cross-sectional study. Patients were classified into three groups based on the results of coronary angiography: a normal coronary artery group (n=15), an angina pectoris group (n=20) and a myocardial infarction group (n=18). Endothelial function was assessed by measuring flow-mediated dilatation after reactive hyperemia in the brachial artery, and serum lipid, lipoprotein (a), glucose and insulin levels were measured. Significant associations were observed between the status of coronary disease and systolic blood pressure, lipoprotein (a), glucose and insulin levels (p <0.05, respectively), and the levels of these risk factors in the myocardial infarction group were higher than those in the other groups. Flow-mediated dilatation was also associated with the status of coronary disease (p <0.05), and the myocardial infarction group showed the lowest levels of flow-mediated dilatation (p <0.05). Flow-mediated dilatation was negatively correlated with systolic and diastolic blood pressures, serum levels of lipoprotein (a), glucose and insulin, and the status of coronary disease. Stepwise multiple regression analysis also revealed that lipoprotein (a), diastolic blood pressure and the status of myocardial infarction were significantly correlated with impaired vasodilatation. Serum lipids, age and smoking habit were independent of flow-mediated dilatation. In conclusion, even after cholesterol-lowering treatment, male patients with myocardial infarction still had endothelial dysfunction, and higher levels of lipoprotein (a) may be associated with endothelial dysfunction in such patients.

Elevated C-reactive protein levels and coronary microvascular dysfunction in patients with coronary artery disease

AIMS

It is still unknown whether elevated C-reactive protein levels are responsible for coronary microcirculatory dysfunction in patients with coronary artery disease (CAD). This study was aimed at evaluating the association between C-reactive protein levels and endothelium-dependent and endothelium-independent coronary blood flow (CBF) responses in non-culprit arteries of patients with CAD.

METHODS AND RESULTS

We studied 28 patients (14 with normal and 14 with elevated C-reactive protein levels, >5 mg/L) with single-vessel disease and otherwise angiographically normal coronary arteries undergoing percutaneous transluminal coronary angioplasty (PTCA). CBF was measured in the non-PTCA vessel using an intracoronary Doppler guide wire and quantitative coronary angiography at baseline, after intracoronary infusion of substance P and of adenosine, and expressed as per cent change from baseline. The increases in CBF during infusion of substance P and of adenosine were lesser in patients with elevated than in those with normal C-reactive protein levels (34+/-22 vs. 61+/-34%, P=0.04 and 131+/-53 vs. 189+/-89%, P=0.03, respectively). Multivariable analysis identified elevated C-reactive protein level as the only independent predictor of reduced response to substance P (P=0.01) and adenosine (P=0.02).

CONCLUSION

In patients with CAD, evidence of systemic inflammation is independently associated with endothelium-dependent and endothelium-independent coronary microvascular dysfunction, which, in turn, may be critical to precipitate myocardial ischaemia, in particular, in unstable patients.

Lack of association between Chlamydia Pneumoniae serology and endothelial dysfunction of coronary arteries

BACKGROUND

Recent publications brought up the hypothesis that an infection with Chlamydia Pneumoniae (CP) might be a major cause of coronary artery disease (CAD). Therefore, we investigated whether endothelial dysfunction (ED) as a precursor of atherosclerosis might be detectable in patients with previous infection with CP but without angiographic evidence of CAD.

METHODS

We included 16 patients (6 male / 10 female) of 52 consecutive patients with normal coronary angiography who had typical angina pectoris and pathologic findings in the stress test. Exclusion criteria were: active smoker, elevated cholesterol, hypertension, age > 65 years, diabetes mellitus, treatment with ACE-inhibitors, or known CAD. Blood sample analysis for serum titer against CP (aCP-IgG) was performed after coronary angiography. We looked for endothelial dysfunction analyzing the diameter of the left anterior descending coronary artery (LAD) before and after acetylcholine (ACh) i. c. Quantitative analysis of luminal diameter (LD) was performed in at least two planes during baseline conditions and after ACh for 2 minutes in dosages of 7.2 microg/min and 36 microg/min with an infusion speed of 2 ml/min. Using Doppler guide wire, the coronary flow velocity was measured continuously in the LAD. The coronary flow velocity reserve (CFVR) was measured after 20 microg adenosine i. c.

RESULTS

10 patients had an elevated aCP-IgG (> 1:8). 6 patients with negative titers (aCP-IgG <or= 1:8) served as control (CTRL). Both groups were comparable in age, gender, angina class, results of non-invasive stress-test and the baseline values of LD and flow. In the CP positive group 3 patients (30%) did not show an increase of LD after ACh as evidence of ED. In the CTRL group 4 patients (67 %) had ED. There was no association between aCP-IgG and changes of coronary blood flow after ACh. All patients showed normal CFVR (3.0 +/- 0.27) irrespective of their aCP-IgG values.

CONCLUSION

In patients with typical symptoms of coronary ischemia but without angiographically visible CAD and absence of other factors affecting the endothelial function, a previous infection with CP is not associated with endothelial dysfunction.

Endothelium-ameliorating effects of statin therapy and coenzyme Q10 reductions in chronic heart failure

Although not currently indicated for chronic heart failure (CHF), statins have been associated with improved outcome in retrospective analysis. However, statin therapy reduces plasma levels of coenzyme Q(10) (ubiquinone), which may have adverse effects on heart failure states. We hypothesized that atorvastatin treatment improves endothelial function in patients with chronic heart failure independent of LDL-cholesterol alterations. Furthermore, we assessed how reductions in coenzyme Q(10) levels impact on potentially improved endothelial function. Twenty-four patients with stable, symptomatic heart failure (New York Heart Association Class II or III) and a left ventricular ejection fraction <40% were randomised to 40 mg atorvastatin or placebo for 6 weeks and crossed over to the other treatment arm for a further 6 weeks, after a 2-week wash out. Forearm resistance vessel function was assessed by venous occlusion plethysmography during infusion of acetylcholine (ACh), sodium nitroprusside (SNP), and N(G)-monomethyl-L-arginine (L-NMMA) into the brachial artery. Atorvastatin treatment lowered triglycerides, LDL-cholesterol and coenzyme Q(10) levels (all p<0.001) and improved endothelium-dependent vasodilatation during acetylcholine infusion (p=0.015). Endothelium-dependent forearm blood flow improvements correlated with reductions in coenzyme Q(10) levels (p=0.011), but not with LDL-cholesterol levels (p=0.084). Coenzyme Q(10) remained the significant variable predicting improvement in NO dependent endothelial function after adjusting for LDL-cholesterol levels (p=0.041). In conclusion, short-term atorvastatin therapy improved endothelial function in chronic heart failure patients. Further studies are required to determine whether coenzyme Q(10) reductions are limiting the maximum favourable effects of statin therapy on the microcirculation.

Fetal and childhood onset of adult cardiovascular diseases

Childhood onset of adult cardiovascular disease has become a significant public health problem. Whether genetic, environmental, or fetal influences are the primary culprits in the epidemic of the cardiovascular disease seen today remains unknown. The benefits of an overall physically active lifestyle that includes weight control, lower blood pressure, avoidance of tobacco use, and consistent exercise are clear and can impact the overall health of children and adolescents. Physicians who care for children and adolescents must begin to incorporate screening of adult cardiovascular disorders into their practice. Better understanding of the etiology of these disease states will bring with it enhanced preventive and targeted therapies.

Effects of statins on vascular structure and function: a systematic review

PURPOSE

Statins reduce cardiovascular events by more than can be explained by their effects on lipids. We conducted a systematic review of how statins affect vascular structure and function, differences among statins, and correlations between the effects of statins on vascular outcomes and either lipid levels or cardiovascular outcomes.

METHODS

We primarily searched MEDLINE (1980 to March 2004) to identify all studies with at least 10 subjects that reported the effects of currently available statins on coronary artery stenosis, carotid intima-media thickness, and endothelial function (excluding studies of drug combinations and subjects with organ transplants). Meta-analyses were performed when feasible.

RESULTS

Statins decrease the progression and increase the regression of coronary artery lesions and luminal narrowing. Compared with placebo, statins decrease the likelihood of coronary artery restenosis (summary risk ratio = 0.85; 95% confidence interval: 0.77 to 0.95). Statins appear to slow the progression of carotid artery intima-media thickness. Although the effect of statins on coronary endothelial function is uncertain, statins appear to improve peripheral endothelial function. There is no conclusive evidence to suggest that individual statins differ in their effects on these outcomes. Studies generally found weak or no correlation between the effects of statins on vascular outcomes and lipid levels. No study showed a correlation between vascular effect and clinical outcome.

CONCLUSION

Statins slow the progression of, and may reverse, atherosclerosis. The magnitude of these effects, however, is small compared with the effects of statins on cardiovascular events. Statins also improve measures of vascular function, which may contribute to their clinical benefits. There is insufficient evidence to suggest that individual statins differ in their vascular effects.

The role of coronary endothelial function testing in patients suspected for angina pectoris

Coronary vasomotor function plays an important role in onset and progression of coronary artery disease. Suwaidi [Circulation 101 (2000) 948] and Schächinger [Circulation 101 (2000) 1899] demonstrated that vasomotor dysfunction has a significant impact on events in patients with minimal coronary artery disease. Endothelial specific testing can be performed in coronary as well as peripheral arteries. However, non-coronary tests have a low correlation with the coronary vasomotor response, as assessed by acetylcholine. In large clinical prospective placebo-controlled trials, angiotensin-converting enzyme (ACE) inhibitors and lipid-lowering drugs reduce morbidity and mortality after myocardial infarction or myocardial infarction-induced heart failure. The same drugs restore endothelial dysfunction after myocardial infarction, as was demonstrated in small experimental and clinical studies. Recent studies in patients with coronary artery disease showed a relation with endothelial dysfunction and the occurrence of adverse coronary events. For this reason, it is important to develop methods to evaluate endothelial function.

Effects of statins on endothelium and their contribution to neovascularization by mobilization of endothelial progenitor cells

Statins are potent drugs with a variety of cardiovascular protective effects which appear to occur independent of cholesterol reduction. The vasculoprotective effects of statins might be due to their direct effect on endothelial cells leading to improved nitric oxide (NO) bioavailability. Mechanistically, statins induce endothelial nitric oxide synthesis (eNOS) mRNA stability in endothelial cells and promote eNOS activity through a PI3K/Akt dependent pathway. Novel targets of statins are pro-angiogenic actions including the mobilization and differentiation of bone marrow derived endothelial progenitor cells, which accelerate angiogenesis or re-endothelialization. The functional improvement and increased homing capacity of endothelial progenitor cells induced by statin treatment might reverse impaired functional regeneration capacities seen in patients with risk factors for coronary artery disease or documented active coronary artery disease.

Statin drugs do not affect serum complement activation in vitro

Statin drugs prevent coronary heart disease through anti-inflammatory mechanisms in addition to the well-known reduction of low-density lipoproteins. The complement system plays an essential role in the inflammatory response and has been postulated to be modified by statins. A direct role for statins in complement activation, however, has not been previously investigated. We therefore studied the effect of statins on in vitro complement activation. Pravastatin, atorvastatin and the active metabolite of the latter, ortho-hydroxy atorvastatin, were added to normal human serum and incubated for 1 h in the absence or presence of aggregated immunoglobulin (classical pathway activation) or cobra venom factor (alternative pathway activation). The degree of complement activation, as detected by specific complement-activation products for the classical pathway (C1rs-C1-inhibitor complexes), the combined classical and lectin pathway (C4bc), the alternative pathway (C3bBbP) and the final common pathway (C3bc and TCC), was not affected by pre-incubation of the serum with any of the statins. Statins do not affect complement activation directly, but indirect effects in vivo may well be operative.

Effect of pravastatin compared with placebo initiated within 24 hours of onset of acute myocardial infarction or unstable angina: the Pravastatin in Acute Coronary Treatment (PACT) trial

BACKGROUND

The efficacy of statin drugs after an acute coronary event is now well established, but the evidence for statin use in the early treatment of acute coronary events remains unclear.

METHODS

We tested the effects of administering pravastatin within 24 hours of the onset of symptoms in patients with unstable angina, non-ST-segment elevation myocardial infarction, or ST-segment elevation myocardial infarction. Patient recruitment of 10,000 with 1200 end points was planned, but the trial was stopped early. A total of 3408 patients were randomly assigned to treatment with pravastatin (1710 patients) or matching placebo (1698 patients). Treatment was continued for 4 weeks. The primary end point of the study was a composite of death, recurrence of myocardial infarction, or readmission to hospital for unstable angina within 30 days of random assignment.

RESULTS

The primary end point occurred in 199 of patients allocated to pravastatin (11.6%) and in 211 patients allocated to placebo (12.4%). A relative risk reduction of 6.4% favored allocation to pravastatin but was not statistically significant (95% CI, -13.2% to 27.6%). No adverse effects were seen.

CONCLUSIONS

We conclude that 20 to 40 mg of pravastatin can be safely administered within 24 hours of the onset of symptoms of an acute coronary event, with a favorable but not significant trend in outcome at 30 days compared with placebo.

Coronary endothelial dysfunction is not rapidly reversible with ascorbic acid

In humans with cardiovascular risk factors, increased vascular production of superoxide anion may contribute to endothelial dysfunction by its reacting with nitric oxide and reducing its biological activity. High concentrations of ascorbic acid scavenge superoxide anion and restore normal endothelium-dependent vasodilation in humans with cardiovascular risk factors. To investigate the contribution of increased superoxide anion to endothelial dysfunction in atherosclerotic coronary arteries, we examined the effect of sequential infusions of ascorbic acid (final concentration 0.1, 1.0, and 10 mmol/L) or placebo on coronary endothelial function in 26 subjects referred for cardiac catheterization to evaluate coronary artery disease. Coronary vasomotor function was evaluated using intracoronary agonist infusion, quantitative angiography, and intracoronary Doppler measurements. At baseline, endothelium-dependent vasodilation of epicardial arteries and coronary microvessels was impaired to an equivalent extent in the ascorbic acid and placebo groups. Sequential ascorbic acid infusions had no effect on the acetylcholine-induced change in coronary artery diameter (-11+/-8, -12+/-10, and -9+/-9%) compared with the effect of placebo (-14+/-13, -16+/-10, and -13+/-9%) infusions (p=0.98). Similarly, the changes in coronary blood flow during acetylcholine infusions were equivalent during ascorbic acid (51+/-44, 67+/-66, and 62+/-52%) and placebo (61+/-104, 55+/-93, and 50+/-69%) infusions (p=0.63). Ascorbic acid also had no effect on the dilator response to intracoronary nitroglycerin (p=0.19). These data argue against an important role for superoxide-mediated "inactivation" of nitric oxide or another rapidly reversible form of oxidative stress as a mechanism of coronary endothelial dysfunction in patients with coronary atherosclerosis.