Beneficial effects of cholesterol-lowering therapy on the coronary endothelium in patients with coronary artery disease

Statin therapy in cardiovascular diseases other than atherosclerosis

Statins are drugs that inhibit 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, thereby blocking the synthesis of cholesterol. Since being discovered in Japan in the mid 1970s, statins have been widely used to lower low-density lipoprotein cholesterol. However, analysis of cardiovascular research has revealed other important effects beyond changes in lipid parameters, referred to as pleiotropic effects. This paper focuses on the effects of statins as anti-ischemic agents with improvement in endothelial function, along with studies on valvular aortic stenosis, atrial fibrillation, heart failure, peripheral arterial disease, and cancer. As the evolution of statin research continues, there appear to be new potential benefits from statins to be found in many facets of cardiovascular disease.

The effects of atorvastatin on coronary endothelial function in patients with recent myocardial infarction

BACKGROUND

Endothelial dysfunction is a key early event in atherosclerosis that occurs in acute coronary syndrome. It was reported that atorvastatin improves the endothelial function of skeletal muscle vessels, but the effect on the coronary artery is unknown.

HYPOTHESIS

The purpose of this study is to determine the effects of atorvastatin on coronary endothelial function in humans.

METHODS

Non-infarct-related coronary arteries of 48 patients with acute myocardial infarction who had undergone successful percutaneous transluminal coronary angioplasty were examined. Three groups were studied: hyperlipidemia with use of atorvastatin (Group 1, n=17), hyperlipidemia without statin use (Group 2, n=18), and normal cholesterol level controls (Group 3, n=13). Statin treatment was started at discharge. Acetylcholine (Ach) was infused into the coronary artery and the diameter was assessed by quantitative angiography at baseline and after 6 months.

RESULTS

Acetylcholine given in doses of 1, 3, 10, and 30 mg/min increased the coronary artery diameter change in a dose-dependent manner. In the initial study, patients in the three groups had similar responses to Ach. The mean diameter change after 6 months was significantly improved in Group 1 compared with Groups 2 and 3 (-11 +/- 3% vs. -20 +/- 7% and -21 +/- 6%, respectively; p < 0.01 in each case). Multivariate regression analysis showed that atorvastatin (p < 0.01) was the significant determinant for improvement of endothelial function.

CONCLUSIONS

These findings suggest that atorvastatin improves endothelial function of the coronary artery in patients with myocardial infarction.

Targeting Nitric Oxide With Drug Therapy

Increasing knowledge of the role of nitric oxide (NO) in physiology and disease has stimulated efforts to target the NO pathway pharmacologically. These therapeutic strategies include NO donors that directly or indirectly release NO and agents that increase NO bioactivity. Traditional organic nitrates such as nitroglycerin, which indirectly release NO, were believed to have limited long-term efficacy and tolerability, chiefly because of nitrate tolerance. Recent studies, however, suggest more effective ways of using these agents and new applications for them. Nicorandil, a hybrid organic nitrate that also activates potassium channels, has demonstrated significant benefits in acute coronary syndromes. Other nitrates are being investigated for use in neurodegenerative diseases. Direct NO donors include NO gas, which is useful in respiratory disorders, and the more recent classes of diazeniumdiolates, sydnonimines, and S-nitrosothiols. Preliminary data suggest that these agents may be effective as antiatherosclerotic agents as well as in other disease states. In addition, hybrid agents that consist of an NO donor coupled with a parent anti-inflammatory drug, including nonsteroidal anti-inflammatory drugs, have demonstrated enhanced efficacy and tolerability compared with the anti-inflammatory parent drug alone in diverse experimental models. Established drugs that enhance NO bioactivity include antihypertensive agents, particularly angiotensin-converting enzyme inhibitors, calcium channel blockers, and newer vasodilating beta-blockers. In addition, 3-methylglutaryl coenzyme A reductase inhibitors (statins) promote NO bioactivity, both through and independent of lipid lowering. The NO-promoting actions of these established drugs provide some insight into their known benefits and suggest possible therapeutic potential.

Highly Active Antiretroviral Therapy Attenuates Re-Endothelialization and Alters Neointima Formation in the Rat Carotid Artery After Balloon Injury

Highly active antiretroviral therapy (HAART) has led to a sustained decline of HIV-associated morbidity and mortality. HAART exhibits significant side effects, however, such as hyperlipidemia and hyperglycemia, which possibly contribute to accelerated atherosclerosis in HAART-treated patients. In addition, direct effects of HAART on vascular cells have been described, which may promote atherosclerotic lesion formation. The effects of HAART on balloon-induced neointima formation have not been studied previously. The rat carotid artery balloon model was used to evaluate the effects of HAART (lopinavir, ritonavir, lamivudine, and zidovudine) on neointima formation and endothelial recovery. Furthermore, the effects of concomitant administration of the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor rosuvastatin were investigated. HAART-treated animals displayed an increase in lesion size (neointima/media ratio: 1.14 +/- 0.32 vs. 1.31 +/- 0.20 in control vs. HAART; P < 0.05) and an impaired regenerative capacity of the endothelium, as indicated by reduction in endothelial regrowth from an adjacent undilated vessel segment 14 days after injury (re-endothelialization area: 8.29 +/- 1.45 mm vs. 5.09 +/- 0.53 mm in control vs. HAART; P < 0.05). When rosuvastatin was given in addition to HAART, these effects were not observed. In conclusion, HAART inhibited endothelial cell-mediated healing and promoted neointima formation after angioplasty in rats. These deleterious effects were attenuated by cotreatment with rosuvastatin, however. Our studies suggest that currently used drug regimens against HIV infection may lead to an increased risk for restenosis after percutaneous vascular interventions. Moreover, the findings indicate that the additional treatment with statins might counteract these adverse effects by HAART.

Uric acid and xanthine oxidase: future therapeutic targets in the prevention of cardiovascular disease?

Serum uric acid may be an independent risk factor for cardiovascular disease. This review examines this association, potential mechanisms, and explores whether strategies to reduce uric acid will improve outcomes. The recent studies of xanthine oxidase inhibition are given particular focus. Epidemiological evidence supports the theory that uric acid is an independent risk factor for cardiovascular disease. Recent studies of losartan, atorvastatin and fenofibrate suggest that uric acid reduction contributes to the risk reduction offered by these therapies. Several small studies of xanthine oxidase inhibition have shown improvements in measures of cardiovascular function of a similar magnitude to that of other proven preventative treatments. These trial data and the convincing epidemiological evidence mandate that large clinical trials of uric acid-lowering strategies are performed in patients with or at high risk of cardiovascular disease. If such approaches are shown to be effective in reducing cardiovascular events, they would represent a novel and cost-effective preventative approach.

Insulin resistance and endothelial dysfunction: the road map to cardiovascular diseases

Cardiovascular disease affects approximately 60% of the adult population over the age of 65 and represents the number one cause of death in the United States. Coronary atherosclerosis is responsible for the vast majority of the cardiovascular events, and a number of cardiovascular risk factors have been identified. In recent years, it has become clear that insulin resistance and endothelial dysfunction play a central role in the pathogenesis of atherosclerosis. Much evidence supports the presence of insulin resistance as the fundamental pathophysiologic disturbance responsible for the cluster of metabolic and cardiovascular disorders, known collectively as the metabolic syndrome. Endothelial dysfunction is an important component of the metabolic or insulin resistance syndrome and this is demonstrated by inadequate vasodilation and/or paradoxical vasoconstriction in coronary and peripheral arteries in response to stimuli that release nitric oxide (NO). Deficiency of endothelial-derived NO is believed to be the primary defect that links insulin resistance and endothelial dysfunction. NO deficiency results from decreased synthesis and/or release, in combination with exaggerated consumption in tissues by high levels of reactive oxygen (ROS) and nitrogen (RNS) species, which are produced by cellular disturbances in glucose and lipid metabolism. Endothelial dysfunction contributes to impaired insulin action, by altering the transcapillary passage of insulin to target tissues. Reduced expansion of the capillary network, with attenuation of microcirculatory blood flow to metabolically active tissues, contributes to the impairment of insulin-stimulated glucose and lipid metabolism. This establishes a reverberating negative feedback cycle in which progressive endothelial dysfunction and disturbances in glucose and lipid metabolism develop secondary to the insulin resistance. Vascular damage, which results from lipid deposition and oxidative stress to the vessel wall, triggers an inflammatory reaction, and the release of chemoattractants and cytokines worsens the insulin resistance and endothelial dysfunction.From the clinical standpoint, much experimental evidence supports the concept that therapies that improve insulin resistance and endothelial dysfunction reduce cardiovascular morbidity and mortality. Moreover, interventional strategies that reduce insulin resistance ameliorate endothelial dysfunction, while interventions that improve tissue sensitivity to insulin enhance vascular endothelial function. There is general agreement that aggressive therapy aimed simultaneously at improving insulin-mediated glucose/lipid metabolism and endothelial dysfunction represents an important strategy in preventing/delaying the appearance of atherosclerosis. Interventions that 1 correct carbohydrate and lipid metabolism, 2 improve insulin resistance, 3 reduce blood pressure and restore vascular reactivity, and 4 attenuate procoagulant and inflammatory responses in adults with a high risk of developing cardiovascular disease reduce cardiovascular morbidity and mortality. Whether these benefits hold when the same prevention strategies are applied to younger, high-risk individuals remains to be determined.

Novel therapies targeting vascular endothelium

Endothelial dysfunction has been identified as a major mechanism involved in all the stages of atherogenesis. Evaluation of endothelial function seems to have a predictive role in humans, and therapeutic interventions improving nitric oxide bioavailability in the vasculature may improve the long-term outcome in healthy individuals, high-risk subjects, or patients with advanced atherosclerosis. Several therapeutic strategies are now available, targeting both the synthesis and oxidative inactivation of nitric oxide (NO) in human vasculature. Statins seem to be currently the most powerful category of these agents, improving endothelial function and decreasing cardiovascular risk after long-term administration. Other cardiovascular agents improving endothelial function in humans are angiotensin-converting enzyme inhibitors/angiotensin receptors blockers, which increase NO bioavailability by modifying the rennin-angiotensin-aldosterone system. Newer therapeutic approaches targeting endothelial dysfunction in specific disease states include insulin sensitizers, L-arginine (the substrate for endothelial NO synthase [eNOS]) as well as substances that target eNOS "coupling," such as folates or tetrahydrobiopterin. Although there are a variety of strategies to improve NO bioavailability in human endothelium, it is still unclear whether they have any direct benefit at a clinical level.

The nonlipid effects of statins on endothelial function

Hydroxymethylglutaryl-coenzyme A reductase inhibitors or statins constitute one of the wonder drugs of the last 2 decades. Use of this hypolipidemic medication class reduces morbidity and mortality in patients with a wide variety of cholesterol levels. Beneficial effects of the medication are seen in advance of changes in lipids suggesting nonlipid mechanisms may play a role in mediating these benefits of statins. One important nonlipid mechanism by which statins may improve vascular outcomes is restoration of normal endothelial cell function. This review will discuss the nonlipid effects of statins on endothelial cell function to highlight other avenues of benefit conferred by these medications.

Review article: The role of statins in reducing perioperative cardiac risk: physiologic and clinical perspectives

PURPOSE

To review the pathobiology and clinical implications of coronary vulnerable atherosclerotic plaques (VAPs), to discuss the role of statin therapy in VAP stabilization, and the potential benefits of perioperative statin therapy (PST) in reducing perioperative risk of acute coronary syndromes (ACSs).

SOURCE

MEDLINE search using "perioperative", "cardiac morbidity", "atherosclerosis", "vulnerable plaque", "statins" and combinations of these terms as keywords. The reference lists of relevant articles were further reviewed to identify additional citations.

PRINCIPAL FINDINGS

The nonstenotic, yet rupture-prone VAP causes most myocardial infarctions (MIs) and other ACSs, both in the nonsurgical and surgical patients. Large clinical trials in both primary and secondary prevention and in patients with ACSs have demonstrated that statin therapy will reduce cardiovascular morbidity and mortality across a broad spectrum of patient subgroups. These trials also suggest, and laboratory investigations establish, that statins possess favourable vascular effects independent of cholesterol reduction. Statins appear to interfere specifically with the pathophysiologic mechanisms implicated in atherothrombotic disease. Statins reduce vascular inflammation, improve endothelial function, stabilize VAPs, and reduce platelet aggregability and thrombus formation. Recent studies have shown that PST is associated with a reduced incidence of perioperative and long-term cardiovascular complications in high-risk patients. Combined therapy with statins and ss-blockers is a conceptually valid strategy targeting critical steps in the pathogenesis of an ACS.

CONCLUSION

Emerging evidence for the efficacy and safety of PST is promising, especially when combined with ss-blocker therapy in patients at highest risk. Confirmation of this early evidence awaits the results of ongoing and future prospective randomized controlled trials.

Statins and Peripheral Arterial Disease: Potential Mechanisms and Clinical Benefits

Peripheral arterial disease (PAD) is a manifestation of widespread atherosclerosis. Lipid modification (especially with statins) is a component of the treatment of patients with PAD since this condition is considered a coronary heart disease equivalent. This review considers the mechanism of action of statins in PAD. Statins have been shown to reduce the incidence of new coronary events in patients with PAD. However, surveys suggest that many such patients remain undertreated. Statins can also increase walking distance in patients with PAD. There is also evidence that statins can improve renal function in these patients. Several other actions of statins are considered in this review. PAD patients have an increased morbidity and mortality, largely due to myocardial infarction and stroke. Recognizing and treating these high-risk patients as early as possible should be a priority.

Novel “plum pudding” gels as potential drug-eluting stent coatings: Controlled release of fluvastatin

This study evaluated novel structural motifs known as "plum pudding" gels as potential drug-eluting stent coatings. Controlled delivery of a HMG-CoA reductase inhibitor (statin) from the intravascular stent surface represents a potential therapeutic modality for prevention of in-stent restenosis (ISR). In this study, gels were comprised of fluvastatin-loaded thermoresponsive microgel particles containing the relatively hydrophilic N-isopropylacrylamide (NiPAAm), mixed with the more hydrophobic N-tert-butylacrylamide (NtBAAm) in different wt/wt ratios: 85/15, 65/35, and 50/50, randomly dispersed in a 65/35 or 85/15 NiPAAm/NtBAAm copolymer matrix. Fluvastatin release from 5 microm copolymer films was greatest from the most hydrophilic systems and least from the more hydrophobic systems. Release from hydrophobic matrices appeared to be via Fickian diffusion, enabling use of the Stokes-Einstein equation to determine diffusion coefficients. Release from hydrophilic matrices was non-Fickian. Eluted drug retained its bioactivity, assessed as selective inhibition of human coronary artery smooth muscle cell proliferation. When stainless steel stent wires were coated (25 microm thickness) with fluvastatin-loaded 65/35 microgels in an 85/15 copolymer matrix, drug elution into static and perfused flow environments followed similar elution profiles. In contrast to elution from copolymer films cast on flat surfaces, diffusion from stent wires coated with hydrophilic and hydrophobic systems both followed Fickian patterns, with slightly larger diffusion coefficients for elution from the flow system. We conclude that manipulation of the relative hydrophobicities of both microgel and matrix components of "plum pudding" gels results in tightly regulated release of fluvastatin over an extended time period relevant to initiation and propagation of ISR.

Effects of statins on experimental colitis in normocholesterolemic rats

OBJECTIVE

The results of previous studies suggest that statins have a direct anti-inflammatory effect that is not directly related to their cholesterol-lowering activity. The aim of this study was to investigate the effect of simvastatin (SIM) and fluvastatin (FLU) on trinitrobenzene sulfonic acid (TNBS)-induced colonic inflammation in rats.

MATERIAL AND METHODS

The drugs were given for 3 days (0.1 and 1 mg/kg day-1; intraperitoneally) after induction of colitis. The lesions in the distal colon were scored at the macroscopic and microscopic level. Tissue malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen content were assessed and formation of reactive oxygen species and peroxynitrite was monitored by chemiluminescence (CL) assay. Trunk blood was collected for the measurement of serum tumor necrosis factor (TNF)-alpha level.

RESULTS

Treatment with SIM reduced the lesion score of the colitis group at macroscopic level (p<0.05), but there was no effect of treatment with FLU. The increase in colonic MDA level of the colitis group was reduced by both drugs at all doses (p<0.05-0.001). The decrease in GSH and the an increase in MPO activity in the colitis group were reversed by SIM at all doses (p<0.01), but FLU had no effect. An increase in colonic lucigenin CL value in the colitis group was reduced by SIM and FLU at all doses (p<0.001) and an increase in peroxynitrite ratio in the colitis group showed a significant reduction in SIM-treated groups; FLU reduced this effect at a dose of 1 mg/kg (p<0.01). An increase in tissue collagen content and serum TNF-alpha level in the colitis group was reversed by both drugs at all doses (p<0.001).

CONCLUSIONS

SIM and FLU seemed to be beneficial in a TNBS-induced rat colitis model through the prevention of lipid peroxidation, superoxide generation, cytokine production and neutrophil accumulation.

Rosuvastatin attenuates hypertension-induced cardiovascular remodeling without affecting blood pressure in DOCA-salt hypertensive rats

The pleiotropic effects of statins represent potential mechanisms for the treatment of end-organ damage in hypertension. This study has investigated the effects of rosuvastatin in a model of cardiovascular remodeling, the DOCA-salt hypertensive rat. Male Wistar rats weighing 300 to 330 g were uninephrectomized (UNX) or UNX and treated with DOCA (25 mg subcutaneously every fourth day) and 1% NaCl in the drinking water. Compared with UNX controls, DOCA-salt rats developed hypertension, cardiovascular hypertrophy, inflammation with perivascular and interstitial cardiac fibrosis, endothelial dysfunction, and prolongation of ventricular action potential duration at 28 days. Rosuvastatin-treated rats received 20 mg/kg/d of the drug in 10% Tween 20 by oral gavage for 32 days commencing 4 days before uninephrectomy. UNX and DOCA-salt controls received vehicle only. Rosuvastatin therapy attenuated the development of cardiovascular hypertrophy, inflammation, fibrosis, and ventricular action potential prolongation, but did not modify hypertension or vascular dysfunction. We conclude that the pleiotropic effects of rosuvastatin include attenuation of aspects of cardiovascular remodeling in the DOCA-salt model of hypertension in rats without altering systolic blood pressure.

Pravastatin reduces microvascular basal lamina damage following focal cerebral ischemia and reperfusion

Transient ischemia has been shown to damage the basal lamina of the cerebral microvasculature. Other studies proved statins to be beneficial to non-cerebral microvessels. The aim of this study was to determine whether pravastatin pretreatment ameliorates microvascular basal lamina damage following transient ischemia. Using the suture model, we subjected 15 rats to focal ischemia (3 h) and reperfusion (24 h). Rats received pravastatin (20 mg/kg/day) or saline for 4 weeks prior to the experiment. The outcome was determined by a behavior test and the infarct size. Collagen type IV, a marker for an intact basal lamina, and hemoglobin extravasation were measured by Western blot analysis. A ratio (in percentage) between ischemic and contralateral hemispheres was calculated. Pravastatin pretreatment resulted in a significantly better neurological outcome and reduced infarct size (15 +/- 0.5 and 59 +/- 10 mm(3), respectively) compared with controls (12.25 +/- 0.4 and 167 +/- 13 mm(3), respectively, P < 0.01 for both). In controls, loss of collagen type IV was seen in the basal ganglia and in the cortex (43 +/- 4 and 64 +/- 5%, respectively). Pravastatin prevented significant collagen loss (basal ganglia: 106 +/- 17%; cortex: 112 +/- 14%, P < 0.01 for both) and significantly reduced the hemoglobin extravasation compared with controls in the basal ganglia (198 +/- 49 vs. 553 +/- 47%, P < 0.01). Pravastatin pretreatment resulted in a reduction of microvascular basal lamina damage and hemoglobin extravasation following transient ischemia. Pravastatin seems to protect the cerebral microvascular system.

Statins and the endothelium

Statins have been shown to have pleiotropic effects apart from serum lipid-lowering effect in human. One of the major target organs for the effects of statins is the vascular endothelium, which plays an important role in the development of atherosclerosis and angiogenesis. Recent numerous studies have shown that the statins' cholesterol-independent vascular effects appear to involve directly restoring or improving endothelial function by increasing NO production, promoting re-endothelialization after arterial injury, and inhibiting inflammatory responses within the vessel wall that are thought to contribute to atherosclerosis. This review provides an update of the unique effects of statins on endothelial cells including endothelial progenitor cells as well as highlighting the therapeutic potential of statins beyond their established lipid-lowering effects.

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 interaction between left ventricular dysfunction and endothelial function in hypertension

Hypertension, one of the most important risk factors for cardiovascular diseases, is associated with both left ventricular hypertrophy and endothelial dysfunction. Both have been recently recognized as independent predictors of clinical events in different groups of patients. In fact, a dysfunctioning endothelium loses its antiatherosclerotic and antithrombotic action, and, therefore, promotes the atherosclerotic process. Similarly, cardiac hypertrophy is recognized as a powerful and independent risk factor for cardiovascular morbidity and mortality because it predisposes to arrhythmias and maximizes the consequences of acute myocardial ischemia. Recently, an evident interaction has been demonstrated between endothelial dysfunction and left ventricular mass. In particular, the coexistence of both left ventricular hypertrophy and endothelial dysfunction almost doubles the risk for future vascular events in hypertensives. Thus, in hypertensive patients, it is clinically useful to choose an aggressive therapeutic strategy--to reduce left ventricular mass and to improve endothelial function.

The impact of early administration of low-dose atorvastatin treatment on inflammatory process, in patients with unstable angina and low cholesterol level

BACKGROUND

Lipid-lowering agents are known to reduce long-term mortality in patients with stable angina or multiple risk factors. However, the effects of lipid-lowering treatment on inflammatory process during and immediately after the acute phase of unstable angina remain unclear. In this study we assessed the effects of low-dose atorvastatin treatment, on inflammatory process in patients admitted for unstable angina with low cholesterol level.

METHODS

Forty-seven normocholesterolemic patients with unstable angina were randomized into two groups, and received atorvastatin 10 mg/day (n = 24) or no statin (n = 23) for 6 weeks. Circulating levels of inteleukin 6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor alpha (TNF-alpha) and soluble vascular cell adhesion molecule (sVCAM-1) were measured by their admission, and at the 1st and 6th week of the study.

RESULTS

Serum levels of MCP-1 and sVCAM-1 were significantly increased in the control group (p < 0.05) while remained unaffected in the atorvastatin-treated group six weeks after admission. However, IL-6 and TNF-alpha levels were similarly decreased in both atorvastatin-treated and control groups.

CONCLUSION

Low-dose atorvastatin treatment modifies inflammatory process in patients with unstable angina and low cholesterol level, an effect seen at 6 weeks but not 1 week after admission.

TGF-beta1-induced thrombospondin-1 expression through the p38 MAPK pathway is abolished by fluvastatin in human coronary artery smooth muscle cells

Thrombospondin-1 (TSP-1) and transforming growth factor-beta1 (TGF-beta1) are both implicated in the pathogenesis of in-stent restenosis. This study evaluated the hypothesis that the HMG-CoA reductase inhibitor fluvastatin inhibits TGF-beta1 induced TSP-1 expression via inhibition of p38 mitogen activated protein kinase (MAPK) phosphorylation in human coronary artery smooth muscle cells (HCASMC) and may therefore have anti-restenosis potential. Fluvastatin significantly reduced TSP-1 mRNA and protein expression in HCASMC in a concentration-dependent manner with a significant reduction in expression observed after treatment with 0.25 microM fluvastatin. TGF-beta1 (5 ng/ml) induced phosphorylation of p38 MAPK and induced TSP-1 mRNA and protein expression in HCASMC. Fluvastatin abolished TGF-beta1-induced phosphorylation of p38 MAPK and TGF-beta1-induced TSP-1 expression. Blockade of the p38 MAPK pathway with the upstream inhibitor SB-203580 also abolished TGF-beta1-induced TSP-1 expression. We conclude that fluvastatin decreases expression of TSP-1 and abolishes the ability of TGF-beta1 to induce TSP-1 expression in HCASMC; this may be achieved by preventing signalling through the p38 MAPK pathway. Targeted delivery of fluvastatin may therefore be a useful therapeutic objective for prevention of the intimal hyperplasia associated with in-stent restenosis.

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.

The regulation and pharmacology of endothelial nitric oxide synthase

Nitric oxide (NO) is a small, diffusible, lipophilic free radical gas that mediates significant and diverse signaling functions in nearly every organ system in the body. The endothelial isoform of nitric oxide synthase (eNOS) is a key source of NO found in the cardiovascular system. This review summarizes the pharmacology of NO and the cellular regulation of endothelial NOS (eNOS). The molecular intricacies of the chemistry of NO and the enzymology of NOSs are discussed, followed by a review of the biological activities of NO. This information is then used to develop a more global picture of the pharmacological control of NO synthesis by NOSs in both physiologic conditions and pathophysiologic states.

Oxidative Stress and Vascular Disease

There is compelling evidence that oxidative stress plays a key role in the pathophysiology of several major cardiovascular diseases. In atherosclerosis, hypertension, stroke, diabetes, and heart failure, expression of superoxide is increased in blood vessels, and endothelial vasomotor function is impaired, presumably caused in large part by inactivation of nitric oxide by superoxide. Endothelial dysfunction is predictive of cardiovascular risk, and probably plays a key role in the pathophysiology of atherosclerosis and its complications. In preliminary studies in hypercholesterolemic mice and in older humans, we have found high levels of superoxide in the aortic valve, as well as aorta. We speculate that superoxide, in addition to playing a key role in atherogenesis, may play a key role in signaling that leads to calcific aortic valvular stenosis. Antioxidant enzymes, especially the three isoforms of superoxide dismutase (SOD), modulate basal levels of superoxide and protect against vasomotor dysfunction. A common gene variant of extracellular SOD (ecSOD) is associated with increased risk of ischemic heart disease. We have made recombinant adenoviruses to examine cardiovascular effects of ecSOD and its heparin-binding domain. This approach might be used to study the almost 500 other proteins with a heparin-binding domain. Finally, several key unanswered questions in relation to oxidative stress and atherosclerosis are raised, and proposed as fruitful areas of research.

Statins in nephrotic syndrome: a new weapon against tissue injury

The nephrotic syndrome is characterized by metabolic disorders leading to an increase in circulating lipoproteins levels. Hypertriglyceridemia and hypercholesterolemia in this case may depend on a reduction in triglyceride-rich lipoproteins catabolism and on an increase in hepatic synthesis of Apo B-containing lipoproteins. These alterations are the starting point of a self-maintaining mechanism, which can accelerate the progression of chronic renal failure. Indeed, hyperlipidemia can affect renal function, increase proteinuria and speed glomerulosclerosis, thus determining a higher risk of progression to dialysis. 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase is the rate-limiting enzyme in cholesterol synthesis from mevalonate and its inhibitors, or statins, can therefore interfere with the above-mentioned consequences of hyperlipidemia. Statins are already well known for their effectiveness on primary cardiovascular prevention, which cannot be explained only through their hypolipemic effect. As far as kidney diseases are concerned, statin therapy has been shown to prevent creatinine clearance decline and to slow renal function loss, particularly in case of proteinuria, and its favorable effect may depend only partially on the attenuation of hyperlipidemia. Statins may therefore confer tissue protection through lipid-independent mechanisms, which can be triggered by other mediators, such as angiotensin receptor blockers. Possible pathways for the protective action of statins, other than any hypocholesterolemic effect, are: cellular apoptosis/proliferation balance, inflammatory cytokines production, and signal transduction regulation. Statins also play a role in the regulation of the inflammatory and immune response, coagulation process, bone turnover, neovascularization, vascular tone, and arterial pressure. In this study, we would like to provide scientific evidences for the pleiotropic effects of statins, which could be the starting point for the development of new therapeutical strategies in different clinical areas.

Statin Use and Functional Decline in Patients With and Without Peripheral Arterial Disease

OBJECTIVES

We determined whether statin use (vs. non-use) is associated with less annual decline in lower-extremity functioning in patients with and without lower-extremity peripheral arterial disease (PAD) over three-year follow-up.

BACKGROUND

It is unclear whether statin use is associated with less functional decline in patients with PAD.

METHODS

Participants included 332 men and women with an ankle brachial index (ABI) <0.90 and 212 with ABI 0.90 to 1.50. Functional outcomes included 6-min walk distance and usual and rapid-pace 4-m walking velocity. A summary performance score combined performance in walking speed, standing balance, and time for five repeated chair rises into an ordinal score ranging from 0 to 12 (12 = best).

RESULTS

Adjusting for age, race, gender, comorbidities, education, health insurance, total cholesterol/high-density lipoprotein level, body mass index, pack-years of smoking, leg symptoms, immediately previous year functioning, statin use/non-use, ABI, and change in ABI, the PAD participants using statins had less annual decline in usual-pace walking velocity (0.002 vs. -0.024 m/s/year, p = 0.013), rapid-pace walking velocity (-0.006 vs. -0.042 m/s/year, p = 0.006), 6-min walk performance (-34.5 vs. -57.9 feet/year, p = 0.088), and the summary performance score (-0.152 vs. -0.376, p = 0.067) compared with non-users. These associations were attenuated slightly by additional adjustment for high-sensitivity C-reactive protein levels. Among non-PAD participants, there were no significant associations between statin use and functional decline.

CONCLUSIONS

The PAD patients on statins have less annual decline in lower-extremity performance than PAD patients who are not taking statins.

Endothelial dysfunction: a comprehensive appraisal

The endothelium is a thin monocelular layer that covers all the inner surface of the blood vessels, separating the circulating blood from the tissues. It is not an inactive organ, quite the opposite. It works as a receptor-efector organ and responds to each physical or chemical stimulus with the release of the correct substance with which it may maintain vasomotor balance and vascular-tissue homeostasis. It has the property of producing, independently, both agonistic and antagonistic substances that help to keep homeostasis and its function is not only autocrine, but also paracrine and endocrine. In this way it modulates the vascular smooth muscle cells producing relaxation or contraction, and therefore vasodilatation or vasoconstriction. The endothelium regulating homeostasis by controlling the production of prothrombotic and antithrombotic components, and fibrynolitics and antifibrynolitics. Also intervenes in cell proliferation and migration, in leukocyte adhesion and activation and in immunological and inflammatory processes. Cardiovascular risk factors cause oxidative stress that alters the endothelial cells capacity and leads to the so called endothelial "dysfunction" reducing its capacity to maintain homeostasis and leads to the development of pathological inflammatory processes and vascular disease.

There are different techniques to evaluate the endothelium functional capacity, that depend on the amount of NO produced and the vasodilatation effect. The percentage of vasodilatation with respect to the basal value represents the endothelial functional capacity. Taking into account that shear stress is one of the most important stimulants for the synthesis and release of NO, the non-invasive technique most often used is the transient flow-modulate "endothelium-dependent" post-ischemic vasodilatation, performed on conductance arteries such as the brachial, radial or femoral arteries. This vasodilatation is compared with the vasodilatation produced by drugs that are NO donors, such as nitroglycerine, called "endothelium independent". The vasodilatation is quantified by measuring the arterial diameter with high resolution ultrasonography. Laser-Doppler techniques are now starting to be used that also consider tissue perfusion.

There is so much proof about endothelial dysfunction that it is reasonable to believe that there is diagnostic and prognostic value in its evaluation for the late outcome. There is no doubt that endothelial dysfunction contributes to the initiation and progression of atherosclerotic disease and could be considered an independent vascular risk factor. Although prolonged randomized clinical trials are needed for unequivocal evidence, the data already obtained allows the methods of evaluation of endothelial dysfunction to be considered useful in clinical practice and have overcome the experimental step, being non-invasive increases its value making it use full for follow-up of the progression of the disease and the effects of different treatments.

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.

Effects of early administration of atorvastatin treatment on thrombotic process in normocholesterolemic patients with unstable angina

BACKGROUND

Although statin-treatment during the acute phase of unstable coronary syndromes improve the outcome their effects on thrombosis/fibrinolysis system in normocholesterolemic patients admitted with unstable angina remain obscure. We assessed the effects of short-term atorvastatin treatment on thrombotic/fibrinolysis markers in normocholesterolemic in patients with unstable angina.

METHODS

Forty-five patients with unstable angina were allocated into two groups to receive atorvastatin 10 mg/day (n = 24) or no statin (n = 21) for 6 weeks. Circulating levels of von Willebrand Factor (vWF), factor V (fV), protein C (prC), tissue plasminogen activator (tPA) and antithrombin III (ATIII) were measured by enzyme linked immunosorbent assay, by the patients admission and at the 1st and 6th week of the study.

RESULTS

After 1 week of treatment, a significant increase of ATIII (p < 0.05), fV (p < 0.01) and vWF (p < 0.05) was found in the control group, but not in atorvastatin-treated group. Similarly, at 6 weeks after admission, plasma levels of ATIII were still significantly higher than at baseline in controls (p < 0.05), but not in atorvastatin-treated group. Plasma levels of PrtC were significantly increased in both controls (p < 0.01) and atorvastatin-treated patients (p < 0.05) at 1 week, while remained unaffected in atorvastatin-treated group at 6th week. There was no significant difference in the variations of plasma levels of tPA, PrtS and fVII between the two groups at 1 and 6 weeks after admission.

CONCLUSIONS

In normocholesterolemic patients admitted with unstable angina the early administration of atorvastatin, significantly affects von Willebrand factor levels and the expression of liver-derived components of both thrombosis and fibrinolysis system.

Time course of rapid C-reactive protein reduction by pravastatin in patients with stable angina

The evidence has indicated that rapid reduction of inflammatory marker, such as C-reactive protein (CRP) could be achieved by administration of a statin. However, limited information is available in evaluating the short-term time course of CRP reduction in patients with coronary artery disease by use of a statin. Forty-two patients with stable angina were randomly assigned to 20 mg/d or 40 mg/d group of pravastatin. Blood samples were drawn at days 0, 1, and 14 for measuring lipid profile, CRP levels, and hepatic enzymes in all patients. The results showed that both doses of pravastatin induced significant reductions in median CRP levels and in mean CRP levels, respectively, at day 1 (20% in the 20 mg/d group and 17.6% in the 40 mg/d group; 15% in the 20 mg/d group and 10% in the 40 mg/d group) as well as at day 14 (28.6% in the 20 mg/d group and 33.3% in the 40 mg/d group; 25% in the 20 mg/d group and 22.8% in the 40 mg/d group) compared with baseline data without a dose-dependent manner. In addition, no changes were found at day 1 regarding lipid profile; however, both doses of pravastatin induced significant reductions in total cholesterol (TC, 22% and 30%), and low-density lipoprotein (LDL) cholesterol (30% and 40%) compared with baseline at 14 days. The higher dose of pravastatin resulted in significantly greater reductions in TC and LDL cholesterol compared with the 20 mg/d dose (p = 0.05, p = 0.01, respectively). A less significant reduction was observed in triglycerides level (16% and 24%) compared with TC and LDL cholesterol. There was no significant difference in mean high-density lipoprotein (HDL) cholesterol levels compared with baseline in both groups. These data suggested that a common daily dose of pravastatin resulted in rapid reduction of CRP within 24 hours and of lipid profile within 2 weeks, and the benefit to the vascular endothelium might occur quickly by reduction of CRP levels, which may be clinically important for patients in a high-risk subgroup, such as acute coronary artery disease.

Protection of endothelial function: targets for nutritional and pharmacological interventions

The vascular endothelium synthesizes and releases a spectrum of vasoactive substances and therefore plays a fundamental role in the basal and dynamic regulation of the circulation. Nitric oxide (NO)-originally described as endothelium-derived relaxing factor-is released from endothelial cells in response to shear stress produced by blood flow, and in response to activation of a variety of receptors. After diffusion from endothelial to vascular smooth muscle cells, NO increases intracellular cyclic guanosine-monophosphate concentrations by activation of the enzyme guanylate cyclase leading to relaxation of the smooth muscle cells. NO has also antithrombogenic, antiproliferative, leukocyte-adhesion inhibiting effects, and influences myocardial contractility. Endothelium-derived NO-mediated vascular relaxation is impaired in spontaneously hypertensive animals. NO decomposition by free oxygen radicals is a major mechanism of impaired NO bioavailability. The resulting imbalance of endothelium-derived relaxing and contracting substances disturbs the normal function of the vascular endothelium. Endothelin acts as the natural counterpart to endothelium-derived NO. Besides its arterial blood pressure rising effect in humans, endothelin-1 induces vascular and myocardial hypertrophy, which are independent risk factors for cardiovascular morbidity and mortality. Current therapeutic strategies concentrate mainly on lowering low-density lipoprotein cholesterol and an impressive reduction in the risk for cardiovascular morbidity and mortality has been achieved. Inflammatory mechanisms play an important role in vascular disease and inflammatory plasma markers correlate with prognosis. The production of reactive oxygen species under pathological conditions may represent an important inflammatory trigger. Novel therapeutic strategies specifically targeting inflammation thus bear great potential for the prevention and treatment of atherosclerotic vascular disease. In this context, the vascular actions of flavanol-rich cocoa, particularly with regard to enhanced NO synthesis and endothelial function observed in humans following consumption, warrants further attention. This review discusses pharmacological and dietary intervention.

Other than potency, are all statins the same?

Statins have been shown to interact with metabolic pathways that potentially affect physiologic functions beyond cholesterol balance. We may broadly categorize non-lipid effects of statins as clinically favorable or clinically detrimental. Whether non-lipid effects of statins are of clinical significance and whether there are differences in non-lipid effects among statins remain points of major current controversy. This review evaluates the available information on potential differences among statins in non-lipid effects.

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.

Pregnancy-Related Hyperlipidemia and Endothelial Function in Healthy Women

BACKGROUND

The purpose of the present study was to investigate pregnancy-related changes in the maternal serum lipid profile and endothelial function.

METHODS AND RESULTS

As part of the population-based, prospective cohort Cardiovascular Risk in Young Finns study conducted in Finland, 57 pregnant Finnish women and 62 control women matched for age and smoking were examined throughout gestation. Serum triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were determined and concomitantly endothelium-dependent brachial artery flow mediated dilation (FMD) was measured by ultrasound. During pregnancy serum TC, LDL-C, HDL-C, TG and very-low-density lipoprotein cholesterol increased significantly when compared with the non-pregnant state (p<0.001 for each) and towards the end of pregnancy (p<0.001, p<0.001, p=0.007, p<0.001, p<0.001). FMD increased towards the end of pregnancy and there was a statistically significant direct correlation between gestational age and FMD% (r=0.345, p=0.010). Brachial artery diameter at rest and FMD% were negatively correlated in pregnant (r=-0.280, p=0.035) and non-pregnant women (r=-0.360, p<0.004). The univariate correlation analysis showed a direct correlation between maternal serum TC (r=0.333, p=0.012) and TG (r=0.366, p=0.006) and FMD%, whereas a negative non-significant correlation was found in non-pregnant women. In a multivariate model, vessel size (beta=-0.436, p=0.001) and TG (beta=0.502, p<0.001) were the most powerful predictors for FMD% in pregnancy, the influence of other lipids was non-significant.

CONCLUSIONS

In healthy pregnant women increased gestational age is associated with improved endothelium-dependent vasodilation responses regardless of concurrently appearing lipid changes.

Inflammatory markers and serum lipids in idiopathic dilated cardiomyopathy

Coronary microcirculation is impaired in idiopathic dilated cardiomyopathy (IDC), possibly because of endothelial dysfunction. High-density lipoproteins (HDLs) have the potential to regulate endothelial function and modulate inflammation and the innate immune response. This study investigated whether reduced HDLs, concomitantly with the activation of inflammation, are associated with IDC. Fifty-five patients with IDC, without evidence of other organ or systemic, chronic, or recurrent diseases, were compared with 55 healthy controls for HDLs and complete lipid profiles, C-reactive protein, C3 and C4 complement fractions, soluble intercellular adhesion molecule-1 and soluble endothelial leukocyte adhesion molecule-1, haptoglobin, and ceruloplasmin. Patients with IDC differed from controls, with lower HDL levels, lower apolipoprotein A-I and A-II levels, and higher triglyceride levels, but not on total and low-density lipoprotein cholesterol, apolipoprotein B, or lipoprotein(a). In addition, all measured inflammation markers were significantly greater in patients with IDC than in controls and were negatively correlated with HDLs. A strong and independent association with IDC was found for age, soluble intercellular adhesion molecule-1, and HDLs that, when categorized as <40 or >40 mg/dl, showed the strongest association (prevalence odds ratio 0.10, p <0.0005) with the disease. In conclusion, the data here reported on reduced HDLs and increased endothelial inflammatory activation and the linear negative correlation between HDLs and inflammation markers, particularly soluble intercellular adhesion molecule-1, could suggest a role for HDLs in the endothelial-microvascular dysfunction seen in IDC.

Rho GTPases, statins, and nitric oxide

The lipid-lowering drugs, 3-hydroxy-3-methylgulutaryl-coenzyme A (HMG-CoA) reductase inhibitors or statins, are used in the prevention and treatment of cardiovascular diseases. Recent experimental and clinical studies suggest that statins may exert vascular protective effects beyond cholesterol reduction. For example, statins improve endothelial function by cholesterol-dependent and -independent mechanisms. The cholesterol-independent or "pleiotropic" effects of statins include the upregulation and activation of endothelial NO synthase (eNOS). Because statins inhibit an early step in the cholesterol biosynthetic pathway, they also inhibit the synthesis of isoprenoids such as farnesylpyrophosphate and geranylgeranylpyrophosphate, which are important posttranslational lipid attachments for intracellular signaling molecules such as the Rho GTPases. Indeed, decrease in Rho GTPase responses as a consequence of statin treatment increases the production and bioavailability of endothelium-derived NO. The mechanism involves, in part, Rho/Rho-kinase (ROCK)-mediated changes in the actin cytoskeleton, which leads to decreases in eNOS mRNA stability. The regulation of eNOS by Rho GTPases, therefore, may be an important mechanism underlying the cardiovascular protective effect of statins.

Endothelial urocortin has potent antioxidative properties and is upregulated by inflammatory cytokines and pitavastatin

BACKGROUND

Urocortin, a neuropeptide discovered in the midbrain, is a member of the corticotropin-releasing factor family and is expressed in heart tissues. Urocortin exerts potent cardioprotective effects under various pathological conditions including ischemia/reperfusion. However, the regulation and function of vascular urocortin are unknown.

METHODS AND RESULTS

Immunohistochemistry showed definitive expression of urocortin in endothelial cells of coronary large arteries and microvessels from autopsied hearts. RT-PCR confirmed the expression of urocortin in human umbilical vein endothelial cells (HUVECs). Urocortin (10(-8) M) potently suppressed the generation of angiotensin II-induced reactive oxygen species (ROS) in HUVECs. Tumor necrosis factor-alpha and interferon-gamma increased the urocortin mRNA levels and its release from HUVECs. Incubation with pitavastatin (0.1-3.0 microM) significantly increased the urocortin mRNA levels and its release from HUVECs. Furthermore, treatment with pitavastatin (2 mg/day) for 4 weeks increased the serum urocortin level from 11.0 +/- 6.5 to 16.4 +/- 7.3 ng/ml in healthy volunteers.

CONCLUSION

Endothelial urocortin was upregulated by inflammatory cytokines and pitavastatin and suppressed ROS production in endothelial cells. Treatment with pitavastatin increased the serum urocortin level in human subjects. Thus, endothelial urocortin might protect cardiomyocytes in inflammatory lesions. Urocortin might partly explain the mechanisms of various pleiotropic effects of statins.

Potential vascular benefits of statins

Atherosclerosis is associated with a number of functional abnormalities that affect endothelium-dependent vasomotor function, inflammation, and thrombosis. The 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) have effects on many of these functions, likely explaining their benefit in reducing the incidence of clinical events in patients at high risk of cardiovascular disease. Statins may improve this vascular biology by lowering levels of low-density lipoprotein (LDL) or potentially by a number of non-LDL-related mechanisms. Cell culture and some animal studies have demonstrated LDL-independent effects of statins. The non-LDL mechanisms include effects on isoprenoid production and function, interactions between caveolin and nitric oxide synthase, and direct immunomodulatory effects. Although these mechanisms are clearly demonstrated in the experimental setting, their relevance to the clinical use of statins is unknown. From a purely pragmatic viewpoint, the debate of lipid versus nonlipid effects of statins matters little to clinical practice. Their proven effect on vascular biology and risk reduction justifies their important therapeutic role.

A rationale for combination therapy in risk factor management: a mechanistic perspective

Endothelial dysfunction contributes to mechanisms of atherogenesis and its clinical manifestations, including coronary heart disease. Cardiovascular risk factors have been linked directly to a loss of endothelial function, such as endothelium-dependent nitric oxide (NO) release, resulting in abnormal vasodilation in response to various stimuli. There is evidence that multiple risk factors, including hypertension and hyperlipidemia, lead to a synergistic effect on endothelial dysfunction, likely through oxidative stress mechanisms. Damage to the endothelium leads to reduced NO bioavailability and facilitates vessel wall permeability to low-density lipoprotein. Certain agents, including the antihypertensive drug amlodipine and the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) atorvastatin, are known to influence endothelial function and NO bioavailability directly; these properties may contribute to clinical benefits. Recent experimental evidence at the cellular level indicates that these agents stimulate NO release from human endothelial cells in a highly synergistic fashion. The clinical implications of these observations are discussed in this article in the context of cardiovascular risk factor management strategies.

Microvascular endothelial function in subjects with Type 2 diabetes and the effect of lipid-lowering therapy

AIMS

Abnormalities of microvascular and endothelial function are present in subjects with Type 2 diabetes. Although statin therapy improves cardiovascular risk in diabetes, dyslipidaemia in diabetes may be more responsive to combined statin and fibrate therapy. We examined the effect of cerivastatin and fenofibrate on microvascular function in subjects with Type 2 diabetes with no clinical evidence of cardiovascular disease and near normal lipid levels.

METHODS

Age-, sex-, lipid- and blood pressure-matched subjects with Type 2 diabetes were randomized in double-blind fashion to one of four treatment groups: group 1 placebo/placebo (n=12), group 2 fenofibrate/placebo (n=10), group 3 cerivastatin/placebo (n=20) and group 4 cerivastatin/fenofibrate (n=11). The subjects were recruited from the Lipid in Diabetes Study. Microvascular function was assessed by skin blood flow response to iontophoresis of acetylcholine and sodium nitroprusside and by skin maximum hyperaemia to local heating. Measurements were carried out at baseline and 3 months later.

RESULTS

Although all lipid parameters improved in groups 2-4 after 3 months' therapy, no difference was detected in skin blood flow to iontophoresis or maximum hyperaemia in any of the groups. Highly sensitive c-reactive protein (Hs-CRP) did not change with therapy.

CONCLUSIONS

In conclusion, we were unable to demonstrate any improvement in microvascular endothelial function in non-hyperlipidaemic Type 2 diabetic subjects treated with single or combination lipid-lowering therapy.

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.

Anti-Inflammatory Effects of Statins: Clinical Evidence and Basic Mechanisms

Chronic inflammation is a key feature of vascular disease states such as atherosclerosis. Multiple clinical studies have shown that a class of medications termed statins lower cardiovascular morbidity and mortality. Originally developed to lower serum cholesterol, increasing evidence suggests that these medications have potent anti-inflammatory effects that contribute to their beneficial effects in patients. Here, we discuss the clinical and experimental evidence underlying the anti-inflammatory effects of these agents.

Effect of intensive versus moderate lipid lowering on endothelial function and vascular responsiveness to angiotensin II in stable coronary artery disease

Recent evidence has demonstrated that intensive lipid-lowering therapy with a high-dose statin provides significant clinical benefit beyond moderate lipid-lowering therapy. However, dose-dependent effects of short-term statin therapy on vascular function have not been demonstrated. We studied endothelial function and vascular responsiveness to angiotensin II in patients who had coronary artery diseased and were randomized to receive low- or high-dose atorvastatin (10 or 80 mg, respectively) or placebo. Internal thoracic artery segments were obtained during coronary bypass surgery and studied in vitro. Endothelium-dependent vasodilation was increased with atorvastatin therapy (p = 0.035) but was significantly increased further in patients who received 80 mg compared with those who received 10 mg of atorvastatin (p = 0.05). Endothelium improvement was accompanied by decreased vascular response to angiotensin II (p = 0.039). These findings suggest a mechanism for the clinical benefit of intensive lipid-lowering treatment in coronary heart disease.

Intensity of lipid lowering with statins and brachial artery vascular endothelium reactivity after acute coronary syndromes (from the BRAVER trial)

The time course and differential effects of statin regimens on endothelial function after acute coronary syndromes (ACSs) are unknown and could contribute to the superiority of a more intense strategy. A subset of subjects who were enrolled in the PROVE IT-TIMI 22 trial (n = 50) underwent evaluation of vascular reactivity by high-resolution brachial ultrasound. Endothelium-dependent flow-mediated dilation (FMD) and endothelium-independent sublingual nitroglycerin-mediated dilation (NMD) were measured at baseline and at 48 hours, 1 month, and 4 months after the initiation of 40 mg of pravastatin (n = 26) or 80 mg of atorvastatin (n = 24). After 4 months, low-density lipoprotein cholesterol was decreased by 32% in the atorvastatin group but was not different from baseline after ACS in the pravastatin group. C-reactive protein decreased similarly in the 2 groups. Brachial artery diameters at rest were similar in the 2 groups and at each time point of the trial. FMD and NMD increased significantly after 4 months by 27% and 24%, respectively (p <0.05), with no difference between groups. There was no correlation between the change in FMD and the change in lipids or C-reactive protein. In subjects who had received previous statin therapy (n = 15), there was no significant variation in FMD (p = 0.140) and NMD (p = 0.129). In conclusion, initiation of statin therapy soon after ACS is associated with improvements in endothelium-dependent and independent vascular reactivities after 4 months.

Indication of long-term endothelial dysfunction after sirolimus-eluting stent implantation

AIMS

Endothelial dysfunction has been related both to progression of atherosclerotic disease and to future cardiovascular events. We assessed local epicardial endothelial function 6 months after sirolimus-eluting stent (SES) or bare metal stent (BS) implantation.

METHODS AND RESULTS

In 12 patients (seven SES, five BS), endothelium-dependent vasomotion of a coronary segment 15 mm in length, starting 2 mm distal to the stent, was assessed with quantitative coronary angiography immediately after the procedure and at 6 months follow-up, after intracoronary infusion of acetylcholine. Intravascular ultrasound (IVUS) was performed and coronary flow reserve (CFR) assessed in all patients. At follow-up significant vasoconstriction was seen in SES (median 32% diameter reduction from baseline) but not in BS (median 2% reduction) patients after acetylcholine infusion (P=0.03 for SES vs. BS); endothelium-independent vasodilatation to nitrates did not differ significantly between groups (20% SES, 5% BS, P=0.14). IVUS revealed no late unhealed dissections and CFR was comparable between groups (SES 3.1 vs. BS 3.2, n.s.).

CONCLUSION

SES implantation may have an adverse effect on local endothelium-dependent vasomotor responses compared with BS implantation at 6 months. Long-term clinical consequences of this observation are still unknown.

Effects of statins on vascular function of endothelin-1

1. Although statins have been reported to inhibit the prepro-endothelin-1 (ET-1) gene transcription in endothelial cells, their effects on the vascular function of ET-1 have not been explored. We, therefore, examined the effects of statins on contraction and DNA synthesis mediated by ET-1 in vascular smooth muscle. The effects of statins on contraction induced by ET-1 were compared to those mediated by noradrenaline (NA) and KCl. 2. Simvastatin (SV) induced a concentration-dependent relaxation of tonic contraction mediated by ET-1 (10 nM) (IC50 value of 1.3 microM). The relaxation was also observed in rings precontracted with NA (0.1 microM) and KCl (60 mM). In contrast, pravastatin did not have any effect on the contractions. 3. Endothelial denudation or pretreatment with L-NAME did not prevent the relaxation, but did reduce the relaxant activity of SV. 4. SV prevented Rho activation caused by ET-1 and KCl in aortic homogenates, as assessed by a Rho pulldown assay. 5. The Rho kinase inhibitor HA-1077 mimicked the effects of SV on tonic contractions induced by ET-1, NA and KCl. 6. Pretreatment with the Kv channels inhibitor, 4-aminopyridine, attenuated the ability of SV to relax contractions mediated by ET-1 and NA. 7. In quiescent VSM cells, SV significantly inhibited DNA synthesis and Rho translocation stimulated by ET-1, as assessed by [3H]thymidine incorporation and Western blot, respectively. 8. Inhibition of Rho geranylgeranylation by GGTI-297, or treatment with HA-1077, mimicked the effects of SV on DNA synthesis stimulated by ET-1. 9. The results show that the statin potently inhibits both ET-1-mediated contraction and DNA synthesis via multiple mechanisms. Clinical benefits of statins may result, in part, from their effects on vascular function of ET-1.

Aged garlic extract improves endothelial function in men with coronary artery disease

Endothelium-dependent vasodilation is impaired and predicts the risk of a coronary event in patients with coronary artery disease (CAD). Oxidant stress and increased systemic inflammation may contribute to this endothelial dysfunction. Aged garlic extract (AGE) contains antioxidant compounds and increases nitric oxide production and decreases the output of inflammatory cytokines from cultured cells. The aim of this study was to test the effect of treatment with AGE on brachial artery flow mediated endothelium-dependent dilation (FMD) and circulating markers of oxidative stress and systemic inflammation. The trial included 15 men with angiographically proven CAD in a randomized, placebo-controlled, cross-over design with 2-week treatment and washout periods. During AGE supplementation, FMD increased (44%) significantly (p = 0.04) from the baseline and mainly in men with lower baseline FMD. Levels of FMD at the end of AGE treatment were significantly (p = 0.03) higher compared with the corresponding levels at the end of placebo treatment when the variation in baseline body weight was taken into account. Markers of oxidant stress (plasma oxidized low density lipoprotein and peroxides), systemic inflammation (plasma C-reactive protein ad interleukin-6) and endothelial activation (VCAM-1) did not change significantly during the study. These data suggest that short-term treatment with AGE may improve impaired endothelial function in men with CAD treated with aspirin and a statin. Whether improvement in endothelial function decreases the risk of future cardiovascular events remains to be determined.