3-hydroxy-3-methylglutaryl coenzyme a reductase inhibition prevents endothelial NO synthase downregulation by atherogenic levels of native LDLs: balance between transcriptional and posttranscriptional regulation

Effect of Statin on Radiographic and Clinical Outcomes of Intracranial Aneurysms Treated With Pipeline Embolization: A Propensity Score-Matched Analysis

BACKGROUND AND OBJECTIVES

Studies have shown that use of statin can improve radiographic and clinical outcomes in patients receiving treatment for coronary artery or peripheral vascular stenosis. Statins are thought to be effective by reducing arterial wall inflammation. The same mechanism may have an influence on the efficacy of pipeline embolization device (PED) for intracranial aneurysm treatment. Although this question has been of interest, there is a lack of well-controlled data in the literature. The objective of this study is to analyze the effect of statins on outcomes of aneurysms treated with pipeline embolization through propensity score matching.

METHODS

Patients who underwent PED for unruptured intracranial aneurysms at our institution between 2013 and 2020 were identified. Patients on statin treatment vs those who were not were matched through propensity score by controlling for confounding factors including age, sex, current smoking status, diabetes, aneurysm morphology, volume, neck size, location of aneurysm, history of treatment for the same aneurysm, type of antiplatelet therapy, and elapsed time at last follow-up. Occlusion status at first follow up and last follow-up, and incidence of in-stent stenosis and ischemic complications during the follow-up period were extracted for comparison.

RESULTS

In total, 492 patients with PED were identified, of whom 146 were on statin therapy and 346 were not. After one-to-one nearest neighbor matching, 49 cases in each group were compared. At last follow-up, 79.6%, 10.2%, and 10.2% of cases in the statin therapy group and 67.4%, 16.3%, and 16.3% in the nonstatin group were noted to have Raymond-Roy 1, 2, and 3 occlusions, respectively ( P = .45). No significant difference was observed in immediate procedural thrombosis ( P > .99), long-term in-stent stenosis ( P > .99), ischemic stroke ( P = .62), or retreatment ( P = .49).

CONCLUSION

Statin use does not affect occlusion rate or clinical outcomes in patients treated with PED treatment for unruptured intracranial aneurysms.

The Impact of Simvastatin on Lipidomic Markers of Cardiovascular Risk in Human Liver Cells Is Secondary to the Modulation of Intracellular Cholesterol

Statins are the first-line lipid-lowering therapy for reducing cardiovascular disease (CVD) risk. A plasma lipid ratio of two phospholipids, PI(36:2) and PC(18:0_20:4), was previously identified to explain 58% of the relative CVD risk reduction associated with pravastatin, independent of a change in low-density lipoprotein-cholesterol. This ratio may be a potential biomarker for the treatment effect of statins; however, the underlying mechanisms linking this ratio to CVD risk remain unclear. In this study, we investigated the effect of altered cholesterol conditions on the lipidome of cultured human liver cells (Hep3B). Hep3B cells were treated with simvastatin (5 μM), cyclodextrin (20 mg/mL) or cholesterol-loaded cyclodextrin (20 mg/mL) for 48 h and their lipidomes were examined. Induction of a low-cholesterol environment via simvastatin or cyclodextrin was associated with elevated levels of lipids containing arachidonic acid and decreases in phosphatidylinositol species and the PI(36:2)/PC(18:0_20:4) ratio. Conversely, increasing cholesterol levels via cholesterol-loaded cyclodextrin resulted in reciprocal regulation of these lipid parameters. Expression of genes involved in cholesterol and fatty acid synthesis supported the lipidomics data. These findings demonstrate that the PI(36:2)/PC(18:0_20:4) ratio responds to changes in intracellular cholesterol abundance per se, likely through a flux of the n-6 fatty acid pathway and altered phosphatidylinositol synthesis. These findings support this ratio as a potential marker for CVD risk reduction and may be useful in monitoring treatment response.

Effects of Statin Treatment on Patients with Angina and Normal or Nearly Normal Angiograms

This article offers an updated and comprehensive overview of major findings on the effects of statin treatment in patients with chronic angina but without any epicardial coronary artery with obstructive lesion.

The histone deacetylase inhibitor tubacin mitigates endothelial dysfunction by up-regulating the expression of endothelial nitric oxide synthase

Endothelial nitric oxide (NO) synthase (eNOS) plays a critical role in the maintenance of blood vessel homeostasis. Recent findings suggest that cytoskeletal dynamics play an essential role in regulating eNOS expression and activation. Here, we sought to test whether modulation of cytoskeletal dynamics through pharmacological regulation of histone deacetylase 6 (HDAC6)-mediated tubulin deacetylation affects eNOS expression and endothelial function in vitro and in vivo We found that tubulin acetylation inducer (tubacin), a compound that appears to selectively inhibit HDAC6 activity, dramatically increased eNOS expression in several different endothelial cell lines, as determined by both immunoblotting and NO production assays. Mechanistically, we found that these effects were not mediated by tubacin's inhibitory effect on HDAC6 activity, but rather were due to its ability to stabilize eNOS mRNA transcripts. Consistent with these findings, tubacin also inhibited proinflammatory cytokine-induced degradation of eNOS transcripts and impairment of endothelium-dependent relaxation in the mouse aorta. Furthermore, we found that tubacin-induced up-regulation in eNOS expression in vivo is associated with improved endothelial function in diabetic db/db mice and with a marked attenuation of ischemic brain injury in a murine stroke model. Our findings indicate that tubacin exhibits potent eNOS-inducing effects and suggest that this compound might be useful for the prevention or management of endothelial dysfunction-associated cardiovascular diseases.

Identifying the anti-inflammatory response to lipid lowering therapy: a position paper from the working group on atherosclerosis and vascular biology of the European Society of Cardiology

Dysregulated lipid metabolism induces an inflammatory and immune response leading to atherosclerosis. Conversely, inflammation may alter lipid metabolism. Recent treatment strategies in secondary prevention of atherosclerosis support beneficial effects of both anti-inflammatory and lipid-lowering therapies beyond current targets. There is a controversy about the possibility that anti-inflammatory effects of lipid-lowering therapy may be either independent or not of a decrease in low-density lipoprotein cholesterol. In this Position Paper, we critically interpret and integrate the results obtained in both experimental and clinical studies on anti-inflammatory actions of lipid-lowering therapy and the mechanisms involved. We highlight that: (i) besides decreasing cholesterol through different mechanisms, most lipid-lowering therapies share anti-inflammatory and immunomodulatory properties, and the anti-inflammatory response to lipid-lowering may be relevant to predict the effect of treatment, (ii) using surrogates for both lipid metabolism and inflammation as biomarkers or vascular inflammation imaging in future studies may contribute to a better understanding of the relative importance of different mechanisms of action, and (iii) comparative studies of further lipid lowering, anti-inflammation and a combination of both are crucial to identify effects that are specific or shared for each treatment strategy.

Statin Therapy and Diabetes Do Not Affect Aneurysm Occlusion or Clinical Outcomes After Pipeline Embolization Device Treatment: A Preliminary Study

BACKGROUND

The effect of statins and diabetes on angiographic and clinical outcomes in aneurysms treated with pipelines has not been adequately reported. Our aim is to assess the effect of concurrent statin medications and diabetes mellitus (DM) on aneurysm occlusion status and outcomes in patients treated with the pipeline embolization device.

METHODS

A retrospective review of our institution's database of aneurysms treated with the pipeline embolization device between 2013 and 2017 was conducted. We collected data about statin therapy status and intensity, and identified patients with a documented history of DM. Our primary outcome was aneurysm obliteration seen on digital subtracted angiography or magnetic resonance angiography at last follow-up.

RESULTS

We identified 151 patients with 182 aneurysms for this cohort, with a median radiographic follow-up time of 7.2 months (6.1-14.5). Thirty-nine patients were taking statins, and 112 patients did not receive statins. Log-rank tests revealed no statistically significant difference in occlusion rates between patients with and without statin therapy (P = 0.30). A history of DM was documented in 11 patients, with 14 aneurysms in total; 140 patients with 168 aneurysms had no history of DM. Similarly, there were no differences in occlusion rates between the diabetic and nondiabetic groups in multivariate analysis (P = 0.24). Only 2 patients showed significant in-stent stenosis on angiographic follow up, and both were diabetic.

CONCLUSIONS

Our analysis did not identify a statistically significant association between statin therapy or DM and higher occlusion rates or better outcomes after pipeline embolization. Diabetic patients may have a theoretic risk of significant in-stent stenosis.

Cardiovascular pleiotropic effects of statins and new onset diabetes: is there a common link: do we need to evaluate the role of KATP channels?

INTRODUCTION

Statins are considered the main stay of treatment in the prevention of cardio-vascular morbidity and mortality. They have multiple pleiotropic effects, like stabilization of atherosclerotic plaques, inhibition of platelet aggregation, and vascular smooth muscle proliferation; in addition to their lipid lowering action. Statins manifest these pleiotropic effects because they activate KATP channels in the cardiac and vascular tissue. Simultaneous activation of the KATP channels by statins in β cells of pancreas may inhibit insulin release which may lead to diabetes. Areas covered: Literature published between 1980 and 2016 on cholesterol biosynthesis, new onset diabetes and on the pleiotropic effects of statins, was reviewed. A comprehensive search on PubMed, Embase and Cochrane databases was carried out. Expert opinion: Statins exert their beneficial pleiotropic effects on the cardiovascular system by activating KATP channels in the cardiac and vascular tissue. However, simultaneous activation of KATP channels in the beta cells of pancreas leads to inhibition of insulin release. This disturbs the carbohydrate metabolism and probably leads to diabetes. In our opinion, use of stains should be more judicious and restricted to secondary prevention only.

Kallistatin levels in HIV-infected patients and effects of statin therapy

BACKGROUND

Kallistatin, a serine proteinase inhibitor, has vasodilatory and anti-inflammatory properties and is increased in other inflammatory conditions. We measured kallistatin in HIV for the first time, examined its relationship with inflammation, and determined if statin therapy affected levels.

METHODS

Kallistatin levels were measured in subjects from a randomized, double-blinded, placebo-controlled trial.

RESULTS

One hundred and thirty-five HIV-infected subjects were included. Kallistatin levels were 28.4 μg/mL at baseline and not affected by rosuvastatin. Levels were correlated with high-sensitivity C-reactive protein (hsCRP), interleukin-6, fibrinogen and insulin resistance.

CONCLUSIONS

Kallistatin levels were correlated with some markers of systemic inflammation and should be further explored in the HIV population.

The effects of anti-obesity intervention with orlistat and sibutramine on microvascular endothelial function

INTRODUCTION

Obesity is associated with impaired microvascular endothelial function. We aimed to determine the effects of orlistat and sibutramine treatment on microvascular endothelial function, anthropometric and lipid profile, blood pressure (BP), and heart rate (HR).

METHODS

76 subjects were recruited and randomized to receive orlistat 120 mg three times daily or sibutramine 10 mg daily for 9 months. Baseline weight, BMI, BP, HR and lipid profile were taken. Microvascular endothelial function was assessed using laser Doppler fluximetry and iontophoresis process. Maximum change (max), percent change (% change) and peak flux (peak) in perfusion to acetylcholine (ACh) and sodium nitroprusside (SNP) iontophoresis were used to quantify endothelium dependent and independent vasodilatations.

RESULTS

24 subjects in both groups completed the trial. After treatment, weight and BMI were decreased for both groups. AChmax, ACh % change and ACh peak were increased in orlistat-treated group but no difference was observed for sibutramine-treated group. BP and total cholesterol (TC) were reduced for orlistat-treated group. HR was reduced for orlistat-treated group but was increased in sibutramine-treated group.

CONCLUSION

9 months treatment with orlistat significantly improved microvascular endothelial function. This was associated with reductions in weight, BMI, BP, HR, TC and low density lipoprotein cholesterol. No effect was seen in microvascular endothelial function with sibutramine.

Vascular endothelial dysfunction and pharmacological treatment

The endothelium exerts multiple actions involving regulation of vascular permeability and tone, coagulation and fibrinolysis, inflammatory and immunological reactions and cell growth. Alterations of one or more such actions may cause vascular endothelial dysfunction. Different risk factors such as hypercholesterolemia, homocystinemia, hyperglycemia, hypertension, smoking, inflammation, and aging contribute to the development of endothelial dysfunction. Mechanisms underlying endothelial dysfunction are multiple, including impaired endothelium-derived vasodilators, enhanced endothelium-derived vasoconstrictors, over production of reactive oxygen species and reactive nitrogen species, activation of inflammatory and immune reactions, and imbalance of coagulation and fibrinolysis. Endothelial dysfunction occurs in many cardiovascular diseases, which involves different mechanisms, depending on specific risk factors affecting the disease. Among these mechanisms, a reduction in nitric oxide (NO) bioavailability plays a central role in the development of endothelial dysfunction because NO exerts diverse physiological actions, including vasodilation, anti-inflammation, antiplatelet, antiproliferation and antimigration. Experimental and clinical studies have demonstrated that a variety of currently used or investigational drugs, such as angiotensin-converting enzyme inhibitors, angiotensin AT1 receptors blockers, angiotensin-(1-7), antioxidants, beta-blockers, calcium channel blockers, endothelial NO synthase enhancers, phosphodiesterase 5 inhibitors, sphingosine-1-phosphate and statins, exert endothelial protective effects. Due to the difference in mechanisms of action, these drugs need to be used according to specific mechanisms underlying endothelial dysfunction of the disease.

Endothelial progenitor cells in diabetic patients with myocardial infarction - can statins improve their function?

The effect of statins on endothelial progenitor cells (EPCs) function derived from diabetic patients (DMpts) with acute myocardial infarction (AMI) is unknown. In this study we assess the response of early and late EPCs from diabetic versus non-diabetic patients (NDMpts) with AMI to statins. EPCs were obtained from 10 diabetic and 10 age-matched non-diabetic male patients with AMI. For each patient, cultures of early and late EPCs were performed under 4 different conditions: normal glucose concentration (control); high glucose concentration; normal glucose concentration with atorvastatin supplementation and normal glucose concentration with pravastatin supplementation. To compare the effect of these treatments on EPC function in DMpts versus NDMpts, we performed in vitro: EPC colony-forming units (CFU) assay; cell cycle analysis; viability assessment and expression of the surface markers CXCR4, CD133, CD34 and KDR. Under control conditions, CFU numbers were reduced in DMpts-derived EPCs when compared to those of NDMpts (1.4±0.8 vs 2.6±1.2 CFU/well, P=0.021). When early EPCs from DMpts were cultured in the presence of statins, CFU capacity was restored, surmounting that of NDMpts under control conditions. Statins significantly improved viability of early EPCs and delayed the onset of late EPCs senescence, even in cells from DMpts. In addition, statins induced approximately a 2-fold increase in the proportion of late EPCs in S-phase of the cell cycle (P<0.05). Statins have a beneficial effect on both early and late EPCs from DMpts with AMI. Despite the functional impairment of EPCs from DMpts, they exhibit similar responsiveness to statins as equivalent cells from NDMpts.

Statins as regulators of redox state in the vascular endothelium: beyond lipid lowering

SIGNIFICANCE

Endothelial dysfunction and the imbalance between nitric oxide (NO) and reactive oxygen species production in the vascular endothelium are important early steps in atherogenesis, a major socioeconomic health problem. Statins have well-established roles in primary and secondary prevention of cardiovascular disease (CVD), due to both their lipid-lowering capacity and their pleiotropic properties. It is therefore important to understand the mechanisms by which statins can modify endothelial function and affect atherogenesis.

RECENT ADVANCES

In the last decade, the concept of statin pleiotropy has been reinforced by a large number of cell culture, animal, and translational studies. Statins have been shown to suppress the activity of pro-oxidant enzymes (such as NADPH oxidase) and pro-inflammatory transcriptional pathways in the endothelium. At the same time, they enhance endothelial NO synthase expression and activity while they also improve its enzymatic coupling. This leads to increased NO bioavailability and improved endothelial function.

CRITICAL ISSUES

Despite significant recent advances, the exact mechanisms of statin pleitropy are still only partially understood. The vast majority of the published literature relies on animal studies, while the actual mechanistic studies in humans are limited.

FUTURE DIRECTIONS

The success of statins as endothelium redox-modifying agents with a direct impact on clinical outcome highlights the importance of the endothelium as a therapeutic target in CVD. Better understanding of the mechanisms that underlie endothelial dysfunction could lead to the design of novel therapeutic strategies that target the vascular endothelium for the prevention and treatment of CVD.

Comparison of rosuvastatin versus atorvastatin for preventing postoperative atrial fibrillation

BACKGROUND

Postoperative atrial fibrillation (AF) following cardiac surgery is associated with an increased risk of stroke, prolonged hospitalization, and increased costs. Statin therapy is associated with a lower incidence of postoperative AF. We aimed to compare the preventive effects of rosuvastatin and atorvastatin on postoperative AF.

METHODS

This study included 168 patients undergoing elective cardiac surgery with cardiopulmonary bypass. Patients were divided into 2 groups according to treatment of statin. Group 1 (n = 96) was patients receiving atorvastatin, and group 2 (n = 72) was patients receiving rosuvastatin. Postoperative electrocardiographs (ECGs) and telemetry strips were examined for AF within postoperative period during hospitalization.

RESULTS

The incidences of postoperative AF were 17.9% (n = 17) in group 1 and 22.2% (n = 16) in group 2 (P = .48). Left ventricular end-diastolic diameter (LVEDD) and ejection fraction (EF) were not different between groups. Incidence of diabetes, hypertension, hyperlipidemia, smoking, myocardial infarction in past medical history, family history of atherosclerosis, male sex, drug use, and perioperative features were similar between groups.

CONCLUSIONS

The present study revealed that preoperative rosuvastatin or atorvastatin treatment did not have a different effect in preventing postoperative AF.

Tackling endothelial dysfunction by modulating NOS uncoupling: new insights into its pathogenesis and therapeutic possibilities

Endothelial nitric oxide synthase (eNOS) serves as a critical enzyme in maintaining vascular pressure by producing nitric oxide (NO); hence, it has a crucial role in the regulation of endothelial function. The bioavailability of eNOS-derived NO is crucial for this function and might be affected at multiple levels. Uncoupling of eNOS, with subsequently less NO and more superoxide generation, is one of the major underlying causes of endothelial dysfunction found in atherosclerosis, diabetes, hypertension, cigarette smoking, hyperhomocysteinemia, and ischemia/reperfusion injury. Therefore, modulating eNOS uncoupling by stabilizing eNOS activity, enhancing its substrate, cofactors, and transcription, and reversing uncoupled eNOS are attractive therapeutic approaches to improve endothelial function. This review provides an extensive overview of the important role of eNOS uncoupling in the pathogenesis of endothelial dysfunction and the potential therapeutic interventions to modulate eNOS for tackling endothelial dysfunction.

Dextromethorphan, chlorphenamine and serotonin toxicity: case report and systematic literature review

The aim of this review was to describe a patient with serotonin toxicity after an overdose of dextromethorphan and chlorphenamine and to perform a systematic literature review exploring whether dextromethorphan and chlorphenamine may be equally contributory in the development of serotonin toxicity in overdose. A Medline literature review was undertaken to identify cases of serotonin toxicity due to dextromethorphan and/or chlorphenamine. Case reports were included if they included information on the ingested dose or plasma concentrations of dextromethorphan and/or chlorphenamine, information about co-ingestions and detailed clinical information to evaluate for serotonin toxicity. Cases were reviewed by two toxicologists and serotonin toxicity, defined by the Hunter criteria, was diagnosed when appropriate. The literature was then reviewed to evaluate whether chlorphenamine may be a serotonergic agent. One hundred and fifty-five articles of dextromethorphan or chlorphenamine poisoning were identified. There were 23 case reports of dextromethorphan, of which 18 were excluded for lack of serotonin toxicity. No cases were identified in which serotonin toxicity could be solely attributed to chlorphenamine. This left six cases of dextrometorphane and/or chlorphenamine overdose, including our own, in which serotonin toxicity could be diagnosed based on the presented clinical information. In three of the six eligible cases dextromethorphan and chlorphenamine were the only overdosed drugs. There is substantial evidence from the literature that chlorphenamine is a similarly potent serotonin re-uptake inhibitor when compared with dextrometorphan. Chlorphenamine is a serotonergic medication and combinations of chlorphenamine and dextromethorphan may be dangerous in overdose due to an increased risk of serotonin toxicity.

Effects of atorvastatin and lisinopril on endothelial dysfunction in patients with Behçet's disease

OBJECTIVE

Behçet's disease is a chronic inflammatory vasculitis. Vascular involvement is one of the major complications of Behçet's disease, during the course of the disease. Previous studies showed that ACE inhibitors and statins may improve endothelial functions in endothelial dysfunction. The aim of our study is to compare the effects of atorvastatin and lisinopril to placebo on endothelial dysfunction in patients with Behçet's disease.

PATIENTS AND METHODS

We prospectively studied 92 (48 female) Behçet's patients who were diagnosed according to the International Study Group criteria. Endothelial dysfunction was evaluated by brachial artery flow-mediated dilatation (FMD) method using high-resolution vascular ultrasound device at baseline and after for 3-month therapy. Patients were consecutively randomized into three groups as (atorvastatin (n = 31), lisinopril (n = 31), and placebo groups (n = 30). Patients in atorvastatin group received 20 mg atorvastatin, lisinopril group received 10 mg lisinopril per day, and placebo group received placebo per day for 3 months.

RESULTS

The baseline characteristics of patients were similar among three groups; however, high-sensitive C-reactive protein (hs-CRP) levels were lower in atorvastatin group than placebo group. A significant improvement in FMD was observed in both atorvastatin (5.0 ± 1.4 vs. 12.8 ± 3.6%, P < 0.001) and lisinopril groups (5.0 ± 1.2 vs. 11.4 ± 5.0%, P < 0.001). Partial significant enhancement was observed in placebo group (4.9 ± 1.1% vs. 5.7 ± 1.0, P = 0.002). However, it was lower than the cutoff value for endothelial dysfunction.

CONCLUSION

These findings suggest that atorvastatin and lisinopril improve endothelial functions in Behçet's disease patients. However, large studies are needed to determine the long-term effects of atorvastatin and lisinopril therapy.

Effects of a nutraceutical combination (berberine, red yeast rice and policosanols) on lipid levels and endothelial function randomized, double-blind, placebo-controlled study

BACKGROUND AND AIMS

Some nutraceuticals are prescribed as lipid-lowering substances. However, doubts remain about their efficacy. We evaluated the effects of a nutraceutical combination (NC), consisting of 500 mg berberine, 200mg red yeast rice and 10mg policosanols, on cholesterol levels and endothelial function in patients with hypercholesterolemia.

METHODS AND RESULTS

In this single centre, randomized, double-blind, placebo-controlled study, 50 hypercholesterolemic patients (26 males and 24 females, mean age 55±7 years, total cholesterol 6.55±0.75 mmol/l, BMI 28±3.5) were randomized to 6 weeks of treatment with a daily oral dose of NC (25 patients) or placebo (25 patients). In a subsequent open-label extension of 4 weeks, the whole sample received NC. The main outcome measure was decrease total cholesterol (C) levels in the NC arm. Secondary outcome measures were decreased low-density lipoprotein cholesterol (LDL-C) and triglyceride levels, and improved endothelial-dependent flow-mediated dilation (FMD) and insulin sensitivity in relation to NC. Evaluation of absolute changes from baseline showed significant reductions in NC versus placebo for C and LDL-C (C: -1.14±0.88 and -0.03±0.78 mmol/l, p<0.001; LDL-C: -1.06±0.75 and -00.4±0.54 mmol/l, p<0.001), and a significant improvement of FMD (3±4% and 0±3% respectively, p<0.05). After the extension phase, triglyceride levels decreased significantly from 1.57±0.77 to 1.26±0.63 mmol/l, p<0.05 and insulin sensitivity improved in a patient subgroup with insulin resistance at baseline (HOMA: from 3.3±0.4 to 2.5±1.3, p<0.05). No adverse effect was reported.

CONCLUSIONS

This NC reduces cholesterol levels. The reduction is associated with improved endothelial function and insulin sensitivity.

Simvastatin reduces sympathetic activity in men with hypertension and hypercholesterolemia

Beyond their hypolipidemic effect, statins reduce cardiovascular risk in hypertensive subjects via various mechanisms; one suggested mechanism is that they reduce sympathetic activity. We investigated the hypothesis that simvastatin decreased muscle sympathetic nerve activity (MSNA) in 31 hypertensive subjects with hypercholesterolemia (aged 38.7 ± 10 years). In this randomized, placebo-controlled, double-blinded study, patients were treated with simvastatin (40 mg day(-1); n=15) or placebo (n=16) for 8 weeks. Before and after treatment, we measured MSNA, blood pressure and heart rate. Baroreceptor control of the heart rate, or baroreceptor sensitivity (BRS), was computed by the sequence method, a cross-analysis of systolic blood pressure and the electrocardiogram R-R interval. Blood samples were tested for plasma levels of catecholamines, neuropeptide Y, aldosterone, endothelin and renin activity. Simvastatin significantly reduced MSNA (from 36.5 ± 5 to 27.8 ± 6 bursts per min, P=0.001), heart rate (from 77 ± 6.7 to 71 ± 6.1 beats per min, P=0.01) and both total and low-density lipoprotein cholesterol (from 249 ± 30.6 to 184 ± 28.3 mg dl(-1), P=0.001 and from 169 ± 30.6 to 117 ± 31.2 mg dl(-1), P=0.01, respectively). Simvastatin also improved BRS (from 10.3 ± 4.1 to 17.1 ± 4.3 ms per mm Hg, P=0.04). No changes were observed in systolic or diastolic blood pressures, or in plasma levels of catecholamines, neuropeptide Y, endothelin, aldosterone and renin activity. After simvastatin therapy, MSNA and BRS were inversely related (r=-0.94, P<0.05). In conclusion, we found that, in patients with hypertension and hypercholesterolemia, simvastatin reduced MSNA, and this was related to increased baroreceptor sensitivity.

Protein geranylgeranylation controls collagenase expression in osteoarthritic cartilage

OBJECTIVE

Statins possess anti-inflammatory properties. This study was undertaken to characterize the mechanism of action of statin drugs on collagenase expression in primary human osteoarthritic cartilage tissue.

METHOD

Human articular chondrocytes and cartilage explants from osteoarthritic donors were exposed to simvastatin in the presence or absence of interleukin-1 beta (IL-1beta). Collagenase expression was determined by quantifying levels of matrix metalloproteinase 13 (MMP-13) and MMP-1 mRNA and MMP-13 protein. The mechanism of statin action was tested by addition of farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP) or by using inhibitors of farnesyl transferase (FT) and geranylgeranyl transferase (GGT-1).

RESULTS

Treatment of osteoarthritic chondrocytes with simvastatin decreased mRNA levels of MMP-13 and MMP-1 whether under basal conditions or during stimulation with IL-1beta. MMP-13 protein secreted into the culture media was also decreased. Genes involved in cartilage synthesis (type II collagen and aggrecan) were not down-regulated by simvastatin. Exogenous addition of GGPP completely reversed the statin-mediated decrease in MMP-13 mRNA and protein levels whereas FPP partially reversed the statin-mediated effect. An inhibitor of GGT-1 mimicked the simvastatin-mediated reduction in MMP-13 expression by chondrocytes. Finally, consistent with impacts on MMP-13 and MMP-1 expression, simvastatin as well as the GGT-1 inhibitor both blocked type II collagen degradation in primary human articular cartilage explants.

CONCLUSION

These results suggest that statins modulate chondrocyte metabolism by reducing prenylation of key signaling molecules that control the expression of collagen-degrading enzymes. Our results strongly support the hypothesis that protein prenyltransferases including geranylgeranyl transferase regulate chondrocyte collagenase expression in osteoarthritis.

Cardiovascular and metabolic effects of Berberine

Berberine (BBR) is a natural alkaloid isolated from the Coptis Chinensis. While this plant has been used in Ayurvedic and Chinese medicine for more than 2500 years, interest in its effects in metabolic and cardiovascular disease has been growing in the Western world in the last decade. Many papers have been published in these years reporting beneficial effects in carbohydrate and lipid metabolism, endothelial function and the cardiovascular system. In this review, we report a detailed analysis of the scientific literature regarding this topic, describing the effects and the underlying mechanisms of BBR on carbohydrate and lipid metabolism, endothelial function and the cardiovascular system.

Atherosclerosis induced by chronic inhibition of the synthesis of nitric oxide in moderately hypercholesterolaemic rabbits is suppressed by pitavastatin

BACKGROUND AND PURPOSE

It is not clear if the new 3-hydroxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor pitavastatin prevents atherogenesis by a direct effect. Statins have a cholesterol-lowering effect, so an accessible animal model of atherosclerosis showing only moderate hypercholesterolaemia as in humans, is needed. The effects of pitavastatin were evaluated on atherosclerotic lesions accumulating foam cells derived from macrophages, produced in rabbits with moderate hypercholesterolaemia by chronic inhibition of nitric oxide synthase (NOS).

EXPERIMENTAL APPROACH

White New Zealand rabbits were fed a 0.2% cholesterol diet with the NOS inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) in the same diet. Pitavastatin (0.1 and 0.3 mg x kg(-1)) was given orally once a day for 8 weeks. The aortic arch and thoracic aorta were analysed by histochemistry and atherosclerotic lesions were quantified. The effect of pitavastatin on adhesion of THP-1 cells to endothelial cells, and cholesterol content in RAW264.7 cells incubated with oxidized or acetylated LDL were also investigated.

KEY RESULTS

Atherosclerotic lesions containing foam cells were induced in a model of atherosclerosis in rabbits with moderate hypercholesterolaemia by chronic inhibition of NOS. The area of atherosclerotic lesions was diminished by pitavastatin administration. The adhesion of THP-1 cells and cholesteryl ester content in RAW macrophages were decreased by pitavastatin treatment.

CONCLUSION

Atherosclerosis induced by chronic inhibition of NOS in moderately hypercholesterolaemic rabbits was suppressed by pitavastatin via inhibition of macrophage accumulation and macrophage foam cell formation.

Stimulation of endothelial progenitor cells: a new putative effect of several cardiovascular drugs

The role of vascular endothelium in cardiovascular disorders is well recognized. Mature endothelial cells contribute to the repair of endothelial injury, but they only have a limited capacity to do so. This has led to growing interest and further investigation into circulating endothelial progenitor cells (EPCs) and their role in vascular healing, repair, and postnatal neovascularization. The current perception of vascular health is that of a balance between ongoing injury and resultant vascular repair, mediated at least in part by circulating EPCs. Circulating EPCs play an important role in accelerating endothelialization at areas of vascular damage, and EPC enumeration is a viable strategy for assessing reparative capacity. Recent studies have shown that EPCs are affected both in number and function by several cardiovascular risk factors as well as various cardiovascular disease states, such as hypertension, hypercholesterolemia, and coronary artery disease. The present review summarizes the most relevant studies on the effects of cardiovascular drugs on vascular function and EPCs, focusing on their mechanisms of action.

Defining the regulation of KLF4 expression and its downstream transcriptional targets in vascular endothelial cells

The Kruppel-like factor 2 (KLF2) and Kruppel-like factor 4 (KLF4) transcription factors have recently been shown to act as critical regulators of endothelial homeostasis. While several insights have been made into the signaling mechanisms orchestrating endothelial KLF2 expression, those governing the expression of KLF4 in the vascular endothelium remain largely unknown. Here, we show that diverse vasoprotective stimuli including an atheroprotective shear stress waveform, simvastatin, and resveratrol induce the expression of KLF4 in cultured human endothelial cells. We further demonstrate that the induction of KLF4 by resveratrol and atheroprotective shear stress occurs via a MEK5/MEF2-dependent signaling pathway. Since MEK5 activation is also critical for the expression of KLF2, we assessed the individual contribution of KLF4 and KLF2 to the global transcriptional activity triggered by MEK5 activation. Genome-wide transcriptional profiling of endothelial cells overexpressing KLF4, KLF2, or constitutively active MEK5 revealed that 59.2% of the genes regulated by the activation of MEK5 were similarly controlled by either KLF2 or KLF4. Collectively, our data identify a significant degree of mechanistic and functional conservation between KLF2 and KLF4, and importantly, provide further insights into the complex regulatory networks governing endothelial vasoprotection.

Statins normalize vascular lysyl oxidase down-regulation induced by proatherogenic risk factors

AIMS

Statins are lipid-lowering drugs widely used in the management of vascular diseases. Clinical and experimental evidence suggest that statins improve endothelial function by both cholesterol-lowering-dependent and -independent mechanisms. We have previously shown that endothelial dysfunction induced by risk factors and proinflammatory cytokines is associated with down-regulation of lysyl oxidase (LOX), a key enzyme modulating extracellular matrix maturation and vascular integrity. Our aim was to analyse whether statins could normalize LOX expression impaired by proatherogenic risk factors.

METHODS AND RESULTS

We observed that pharmacological concentrations of statins (atorvastatin and simvastatin) modulated LOX transcriptional activity, counteracting the down-regulation of LOX (at the mRNA, protein, and activity level) caused by tumour necrosis factor-alpha (TNFalpha) in porcine, bovine, and human aortic endothelial cells. Geranylgeraniol but not farnesol reversed this effect, suggesting the involvement of geranylgeranylated proteins. In accordance, inhibitors of RhoA/Rho kinase also counteracted LOX down-regulation caused by TNFalpha, and over-expression of a RhoA dominant-negative mutant mimicked statin effects. Statins were also able to counteract the decrease in LOX expression produced by atherogenic concentrations of LDL by a similar mechanism and to partially prevent the increase in endothelial permeability elicited by these lipoproteins. Finally, in the in vivo porcine model of hypercholesterolaemia, we observed that statins abrogated the reduction of vascular LOX expression triggered by high plasma levels of LDL.

CONCLUSION

These data indicate that statins normalize vascular LOX expression altered by atherogenic risk factors through a RhoA/Rho kinase-dependent mechanism. Thus, modulation of LOX by statins could contribute to vascular protection and to the cardiovascular risk reduction achieved by this therapy.

HMG-CoA reductase inhibitor regulates endothelial progenitor function through the phosphatidylinositol 3'-kinase/AKT signal transduction pathway

HMG-CoA reductase inhibitor (statins) are known to have pleiotropic effects. We examined the effect and mechanism of simvastatin on peripheral endothelial progenitor cells (EPCs). Rats were divided into simvastatin group and the control group after cardiac infarction operation. Simvastatin treatment significantly increased the number of peripheral blood CD34+ CD133+ cells, and serum concentration of vascular endothelial growth factor (VEGF) and AKT was markedly increased in vivo. In cultured EPC, simvastatin increased the concentrations of VEGF, AKT and eNOS. Western blots analysis showed that simvastatin increased the phosphorylation of eNOS and FKHRL1, which can be blocked by the PI3K/AKT pathway blocker LY294002 . Our study demonstrated that simvastatin increases the mobilization of EPCs after cardiac infarction. In in vitro study, simvastatin increases the phosphorylation of eNOS and of FKHRL1 through the PI3K/AKT signaling pathway.

Oleanolic acid induces prostacyclin release in human vascular smooth muscle cells through a cyclooxygenase-2-dependent mechanism

Oleanolic acid is a triterpenoid that may contribute to the cardio-protective effects of olive oil. Our goal was to assess whether oleanolic acid could modulate eicosanoid biosynthesis and to determine the mechanism involved in this effect. Human coronary smooth muscle cells (SMC) were treated with oleanolic acid, erythrodiol, or hydroxytyrosol and eicosanoid release was measured by enzyme immunoassay. Cyclooxygenase (Cox)-1 and Cox-2 protein and messenger sRNA levels were analyzed by Western blot and real-time PCR, respectively. Mitogen-activated protein kinase (MAPK) pathways were assessed using specific antibodies. Oleanolic acid induced prostaglandin I2 (PGI2) release by human coronary SMC, an effect that was prevented by celecoxib (a specific inhibitor of Cox-2). The increased PGI2 was time-and dose-dependent and was associated to the up-regulation of Cox-2. No effects were observed on thromboxane A2. Erythrodiol but not hydroxytyrosol upregulated Cox-2 expression and induced PGI2 synthesis. Oleanolic acid induced an early phosphorylation of p38 MAPK and p42/44 MAPK but not c-Jun N-terminal kinase-1 (JNK-1). SB203580 (p38MAPK inhibitor) and U0126 (MAPK kinase1/2 inhibitor) abrogated the upregulation of Cox-2 and PGI2 release induced by oleanolic acid. A peptide inhibitor of JNK-1 (L-JNKI1) did not produce any effect. The induction of Cox-2 was preceded by an early activation of cAMP regulatory element-binding protein, a key transcription factor involved in Cox-2 transcriptional upregulation. Therefore, oleanolic acid contributes to vascular homeostasis by inducing PGI2 release in a Cox-2-dependent manner. Oleanolic acid could be regarded as a bioactive molecule that may contribute to the beneficial effects of the Mediterranean diet.

Simvastatin reverses the hypertension of heterozygous mice lacking cystathionine beta-synthase and apolipoprotein A-I

Double heterozygous mice lacking Apoa1 and Cbs genes show mild hyperhomocysteinemia in combination with hypoalphalipoproteinemia. This situation leads to a moderate hypertension associated with a dysregulation in nitric oxide metabolism. The aim of this study was to investigate the potential beneficial effects of statin treatment in these mice. After 4 weeks of simvastatin administration, plasma parameters; apolipoproteins A-I, A-II and A-IV; lipid profile; and blood pressure were assessed, Western blotting was performed in the aorta of these mice to measure endothelial nitric oxide synthase and caveolin-1 content. The high blood pressure level present in the double heterozygous group was corrected down to that of the wild-type group after simvastatin treatment (124+/-7.7 vs. 109+/-11.2 mmHg, p<0.01). Concomitant with this effect, an increase in nitric oxide levels was observed in these double heterozygous mice receiving simvastatin treatment probably mediated in part by a decrease in caveolin-1 levels. Blood pressure changes appeared to be independent of the arylesterase activity of paraoxonase or the lipid content. Another remarkable result was the significant increase in apoA-IV content in animals receiving simvastatin, an effect considered to be protective for the endothelium. In conclusion, the results of this study demonstrate that the use of simvastatin can improve blood pressure control in mice with elevated homocysteinemia and low levels of apoA-I, and this effect is mediated by mechanisms independent of plasma lipids and related to nitric oxide levels.

Synergistic effect of amlodipine and atorvastatin in reversing LDL-induced endothelial dysfunction

PURPOSE

Statins and certain calcium channel blockers may improve nitric oxide (NO) release and endothelial function through various mechanisms, but their combined effects are not well understood.

METHODS

The separate versus combined effects of amlodipine (AML) and atorvastatin (AT) on NO and peroxynitrite (ONOO-) were measured in human umbilical vein endothelial cells (HUVEC) in the presence and absence of low-density lipoprotein (LDL) using electrochemical nanosensors.

RESULTS

The combination of AML (5 micromol/l) and AT (3-6 micromol/l) directly stimulated NO release that was about twofold greater than the sum of their separate effects (p < 0.05). This synergistic activity is attributed to enhanced endothelial NO synthase (eNOS) function and decreased cytotoxic ONOO-. LDL (100 mg/dl) caused a dysfunction of HUVEC manifested by a 60% reduction in NO and an almost twofold increase in ONOO-. Treatment with AML/AT partially reversed the effects of LDL on endothelial function, including a 90% increase in NO and 50% reduction in ONOO-. Small-angle X-ray diffraction analysis indicates that AML and AT are lipophilic and share an overlapping molecular location in the cell membrane that could facilitate electron transfer for antioxidant mechanisms.

CONCLUSION

These findings indicate a synergistic effect of AML and AT on an increase in NO concentration, reduction of nitroxidative stress. Also, AML/AT partially restored the NO level of LDL-induced dysfunctional endothelium. Their combined effects may be enhanced by antioxidant properties related to their intermolecular actions in the cell membrane and an increase in the expression and coupling of endothelial nitric oxide synthase.

Simultaneous assessment of endothelial function, nitric oxide synthase activity, nitric oxide-mediated signaling, and oxidative stress in individuals with and without hypercholesterolemia

BACKGROUND

Endothelial function is impaired in hypercholesterolemia and atherosclerosis. Based on mostly indirect evidence, this impairment is attributed to reduced synthesis or impaired biological activity of endothelium-derived nitric oxide (NO). It was the aim of this study to directly estimate and compare whole-body NO production in normo- and hypercholesterolemia by applying a nonradioactive stable isotope dilution technique in vivo.

METHODS

We enrolled 12 normocholesterolemic and 24 hypercholesterolemic volunteers who were all clinically healthy. To assess whole-body NO synthesis, we intravenously administered l-[guanidino-((15)N(2))]-arginine and determined the urinary excretion of (15)N-labeled nitrate, the specific end product of NO oxidation in humans, by use of gas chromatography-mass spectrometry. In addition, we measured flow-mediated vasodilation (FMD) of the brachial artery, expression of endothelial NOS (eNOS) in platelets, plasma concentration of the endogenous NOS inhibitor asymmetric dimethylarginine (ADMA), and urinary excretion of 8-isoprostaglandin F(2alpha) (8-iso-PGF(2alpha)).

RESULTS

After infusion of l-[guanidino-((15)N(2))]-arginine, cumulative excretion of (15)N-labeled-nitrate during 48 h was 40% [95% CI 15%-66%] lower in hypercholesterolemic than normocholesterolemic volunteers [mean 9.2 (SE 0.8) micromol vs 15.4 (2.3) micromol/l, P = 0.003]. FMD was on average 36% [4%-67%] lower in hypercholesterolemic than normocholesterolemic volunteers [6.3 (4.0)% vs 9.4 (4.6)%, P = 0.027]. Normalized expression of NOS protein in platelets was also significantly lower in hypercholesterolemic volunteers, whereas there were no significant differences in plasma ADMA concentration or urinary excretion of 8-iso-PGF(2alpha) between the 2 groups.

CONCLUSIONS

This study provides direct evidence for a decreased whole body NO synthesis rate in healthy people with hypercholesterolemia.

Rosuvastatin prevents endothelial cell death and reduces atherosclerotic lesion formation in ApoE-deficient mice

Accumulating evidence suggests that statins have beneficial effects which are independent of their lipid-lowering actions, on vascular cells. Here, we investigated whether the HMG-CoA reductase inhibitor rosuvastatin can inhibit atherosclerotic lesion development with favorable effects on endothelial cells in ApoE-deficient mice. Rosuvastatin rapidly phosphorylated Akt and endothelial nitric oxide synthase (eNOS) in human endothelial cells. Endothelial cell death induced by serum starvation was significantly inhibited by rosuvastatin (percent cell death; 45.9+/-2.4% vs. 37.3+/-1.1%, p<0.05). Eight-week-old ApoE-deficient mice were orally administered vehicle or rosuvastatin at a dose of 20mg/kg/day for 24 weeks. There was no significant difference in cholesterol profile. Rosuvastatin preserved endothelial lining at the aortic root (CD31-positive luminal side; 63.8+/-2.8% vs. 81.7+/-3.9%, p<0.05). En face Sudan IV staining of aorta revealed that rosuvastatin significantly decreased the atherosclerotic area (21.9+/-2.9% vs. 11.9+/-1.9%, p<0.05). Lipid deposition at the atherosclerotic area was also suppressed by rosuvastatin with more stabilized morphologic features as determined by oil red O staining (3.4+/-0.4% vs. 1.7+/-0.4%, p<0.05). Our findings indicate that rosuvastatin protects endothelial cells from death with phosphorylation of Akt and eNOS. These effects may contribute, at least in part, to the anti-atherosclerotic effects of rosuvastatin.

Neuron-derived orphan receptor-1 (NOR-1) is induced by thrombin and mediates vascular endothelial cell growth

BACKGROUND AND AIM

Neuron-derived orphan receptor-1 (NOR-1) is a transcription factor overexpressed in human atherosclerotic plaques that is involved in vascular smooth muscle cell (VSMC) proliferation. The aim of this study was to analyze the role of NOR-1 in thrombin-induced endothelial cell growth.

RESULTS

Thrombin induced an early and transient up-regulation of NOR-1 in human umbilical vein endothelial cells (HUVEC). NOR-1 up-regulation by thrombin is dependent on multiple pathways, including cytosolic Ca(2+), activation of protein kinase C (PKC), mitogen-activated protein kinase (MAPK) pathways [both extracellular-regulated kinase (ERK) and p38 MAPK], and downstream activation of cAMP response element binding protein (CREB). The critical role of CREB in the induction of NOR-1 by thrombin was demonstrated using a dominant-negative of CREB. By site-direct mutagenesis we identified two CRE sites present at -79 and -53 bp in the NOR-1 promoter involved in the up-regulation of NOR-1 by thrombin. Inhibition of thrombin receptor PAR-1 abolished CREB activation, NOR-1 up-regulation and DNA synthesis (used as an index of cell proliferation). TRAP-6 mimicked both NOR-1 up-regulation and CREB activation induced by thrombin, while PPACK (an irreversible thrombin inhibitor) prevented such an effect. Direct inhibition of thrombin-induced NOR-1 up-regulation, using antisense oligonucleotides or siRNA against NOR-1, reduced DNA synthesis and endothelial cell re-growth after injury in an in vitro model of wound repair.

CONCLUSIONS

These results indicate that NOR-1 up-regulation plays a key role in thrombin-induced endothelial cell growth. Strategies aimed to block NOR-1 could be useful to prevent vascular effects triggered by thrombin.

Lysyl oxidase (LOX) down-regulation by TNFalpha: a new mechanism underlying TNFalpha-induced endothelial dysfunction

OBJECTIVE

TNFalpha is a pro-inflammatory cytokine that induces endothelial dysfunction and promotes atherosclerosis progression. Down-regulation of lysyl oxidase (LOX), a key enzyme in extracellular matrix maturation, by pro-atherogenic risk factors such as LDL and homocysteine, is associated with an impairment of endothelial barrier function. Our hypothesis is that the inflammatory cytokine TNFalpha could also modulate LOX expression/function in endothelial cells.

METHODS

The study was carried out in human umbilical vein endothelial cells (HUVEC), porcine aortic endothelial cells (PAEC) and bovine aortic endothelial cells (BAEC). LOX mRNA levels were analysed by real-time PCR and LOX activity was assessed by a high sensitive fluorescent assay. Promoter activity was determined by transient transfection using a luciferase reporter system.

RESULTS

TNFalpha decreases LOX mRNA levels in endothelial cells in a dose- and time-dependent manner. The effect of TNFalpha was observed at low concentrations (0.1-1 ng/mL) and was maximal at 2.5 ng/mL (after 21 h). In transfection assays, TNFalpha reduced LOX transcriptional activity to a similar extent than LOX mRNA. Furthermore, TNFalpha decreases endothelial LOX enzymatic activity. By using both TNF receptor (TNFR) agonist and blocking antibodies we determined the involvement of TNFR2 on LOX down-regulation. Moreover, while TNFR-associated factor-2 (TRAF-2) did not mediate signalling events leading to LOX inhibition, PKC inhibitors counteracted the TNFalpha-induced decrease of LOX mRNA levels. Finally, TNFalpha administration significantly reduced vascular LOX expression in rat aorta.

CONCLUSIONS

Endothelial dysfunction induced by TNFalpha is associated with a decrease of LOX expression/activity. Thus, LOX seems to be involved in the impairment of endothelial function triggered by different pathological conditions.

Atorvastatin: beyond lipid-lowering effects in the diabetic population

Statins are the mainstay of therapy in coronary artery disease and hypercholesterolemia. Atorvastatin is a 3-hydroxy-3-methylglutaryl coenzyme-A reductase inhibitor that is taken once daily. It has been shown to considerably reduce cardiovascular mortality events. Recently, several trials have demonstrated that atorvastatin has pleiotropic effects beyond its lipid-lowering capacities. Atorvastatin is especially beneficial in diabetics for stroke prevention and improving cardiovascular mortality risk.

NOR-1 is involved in VEGF-induced endothelial cell growth

Neuron-derived orphan receptor-1 (NOR-1) is a transcription factor over-expressed in human atherosclerotic plaques that is involved in vascular smooth muscle cell proliferation. The aim of this study was to analyze whether NOR-1 plays a role in vascular endothelial growth factor (VEGF) induced endothelial cell growth. VEGF induced an early and transient up-regulation of NOR-1 in human umbilical vein endothelial cells (HUVEC). NOR-1 up-regulation by VEGF is processed through VEGF receptor-2 (VEGFR-2) and involves different signaling pathways including increase in cytosolic Ca(2+), activation of protein kinase C and mitogen-activated protein kinase (MAPK) pathways (both extracellular-signaling regulated kinase [ERK] and p38 MAPK). VEGF induced CREB activation (phosphorylation in Ser(133)). In transfection assays, a dominant-negative of CREB inhibited NOR-1 promoter activity, while mutation of the three CRE sites in the NOR-1 promoter abolished VEGF-induced NOR-1 promoter activity. Antisense oligonucleotides against NOR-1 inhibited VEGF-induced endothelial cell growth (reduced DNA synthesis, and inhibited cell cycle progression and endothelial cell wound repair after mechanical injury). These results indicate that NOR-1 could be a key transcription factor regulating endothelial cell growth induced by VEGF.

Is atrial fibrillation an inflammatory disorder?

There is mounting evidence to support the influence of inflammation in the pathogenesis of atrial fibrillation (AF). Indeed, AF is associated with increased levels of known inflammatory markers, even after adjustment for confounding factors. The renin-angiotensin-aldosterone system (RAAS) appears to play a key role in this process. Atrial biopsies from patients with AF have also confirmed the presence of inflammation. Furthermore, there is preliminary evidence to support a number of drug therapies that have the potential to reduce the clinical burden of AF. In this review, we present an overview of the evidence supporting a link between inflammation and AF, and some of the drug therapies, such as the angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, steroids, fish oils, and vitamin C, that might be efficacious in the prevention of AF by modulating inflammatory pathways.

Intermolecular differences of 3-hydroxy-3-methylglutaryl coenzyme a reductase inhibitors contribute to distinct pharmacologic and pleiotropic actions

Statin drugs inhibit 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and share the common mechanism of lowering circulating levels of low-density lipoprotein (LDL) cholesterol, a powerful indicator of risk for cardiovascular disease. Large clinical trials have documented the benefit of hypolipidemic therapy for both primary and secondary prevention of coronary artery disease and stroke. Recent clinical findings, including direct comparator studies, now indicate that certain statins may slow progression of disease at a rate and to an extent that cannot be solely attributed to LDL reduction. The proposed mechanisms for such pleiotropic actions include enhancement of endothelial-dependent nitric oxide bioavailability, anti-inflammatory activity, and inhibition of oxidative stress. To understand the biochemical basis for such differences among statins, this article reviews their physicochemical properties and pharmacology at the molecular level.

Therapeutic potential of nitric oxide donors in the prevention and treatment of atherosclerosis

Well-known risk factors for atherosclerosis include hypercholesterolaemia, hypertension, diabetes, and smoking. These conditions are associated with endothelial dysfunction, which itself is associated with reduced endothelial generation of nitric oxide (NO). This is an overview of the implications of NO generation in atherosclerosis and of the potential therapeutic benefit of drugs which donate NO, such as organic nitrates, nicorandil, and sydnonimines, or those which increase the availability of endogenous NO, such as statins, angiotensin-converting enzyme inhibitors, L-arginine, and tetrahydrobiopterin.

Beneficial effect of simvastatin and pravastatin treatment on adverse cardiac remodelling and glomeruli loss in spontaneously hypertensive rats

The aim of the present study was to investigate the possibility of different effects of the hydrophobic statin simvastatin and the hydrophilic statin pravastatin on the remodelling process in the overloaded left ventricle and renal cortex of SHRs (spontaneously hypertensive rats). Fifteen SHRs were treated for 40 days with simvastatin, pravastatin or placebo (water) via orogastric administration. Left ventricle and renal cortex were examined by light microscopy and stereology. LV (left ventricular) cardiomyocyte nuclei (N[cmn]) and glomeruli (N[gl]) numbers were estimated by the dissector method. BP (blood pressure) and serum triacylglycerols (triglycerides) were lower in the statin-treated groups than in the untreated control group. The volume density of the interstitial connective tissue was smaller and length density of the intramyocardial arteries, as well as the arteries/cardiomyocyte ratio, was greater in the statin-treated groups than in the control group. No difference was observed between the two statin-treated groups. The cross-sectional cardiomyocyte area was significantly smaller in the simvastatin-treated group than in the control or pravastatin-treated groups, and it was smaller in the pravastatin-treated group than in the control group. N[cmn] and N[gl] were greater in the two statin-treated groups than in the control group, but no significant difference was observed between the two statin-treated groups. In conclusion, administration of the statins simvastatin and pravastatin to SHRs effectively prevented the elevation in BP and serum triaclyglycerols, and also attenuated adverse cardiac and kidney remodelling by preventing LV hypertrophy, enhancing myocardial vascularization with the decrease in interstitial fibrosis and attenuating cardiomyocyte and glomerular loss.

The unsaponifiable fraction of virgin olive oil in chylomicrons from men improves the balance between vasoprotective and prothrombotic factors released by endothelial cells

Minor components of virgin olive oil (VOO) may play a key role in the beneficial effects of VOO on atherosclerosis. In the present study we evaluated the influence of the unsaponifiable fraction of VOO on the production of eicosanoids and nitric oxide (NO) by endothelial cells (HUVECs). Triglyceride-rich lipoprotein (TRLs) were isolated from human serum after the intake of meals enriched in 3 high-oleic acid oils, i.e., high-oleic sunflower (HOSO), VOO, or enriched-virgin olive (EVO) oils, the last-mentioned containing 2.4% of unsaponifiable matter. HOSO induced a greater accumulation of triglycerides (TGs) in the postprandial serum than VOO or EVO, as measured by calculating the area under the curve. The incubation with TRLs increased NO release by endothelial cells compared with untreated control cells, but the effects of the various TRLs did not differ. EVO-derived TRLs reduced the production of prostaglandin E(2) (PGE(2)) and thromboxane B(2) (TxB(2)) (the stable metabolite of TxA(2)) compared with VOO- or HOSO-derived TRLs. The release of PGI(2) (as 6-keto PGF(1alpha)) was similarly diminished by all TRLs compared with the control. In conclusion, the unsaponifiable fraction of VOO does not affect postprandial triglyceridemia, but it has favorable effects on endothelial function, mainly by reducing proinflammatory and vasoconstrictor eicosanoid synthesis (PGE(2) and TxB(2)).

Simvastatin potenciates PGI2 release induced by HDL in human VSMC: effect on Cox-2 up-regulation and MAPK signalling pathways activated by HDL

High density lipoproteins (HDL) induce prostacyclin (PGI(2)) release in vascular smooth muscle cells (VSMC) by up-regulation of cyclooxygenase-2 (Cox-2). Our goal was to analyse the mechanisms underlying this effect, and its potential modulation by HMG-CoA reductase inhibition in human VSMC. The contribution of mitogen-activated protein kinase (MAPK) signalling pathways was assessed by Western blot analysis and using specific inhibitors [PD098059 for p42/44 MAPK kinase (MEK); SB203580 for p38 MAPK or L-JNKI1 for c-Jun N-terminal kinase-1 (JNK-1)]. HDL-induced PGI(2) release was inhibited by rofecoxib (a specific Cox-2 inhibitor, 5 microM). HDL induced the early activation of p42 MAPK, p38 MAPK and JNK-1. p42/44 MAPK was the major pathway involved in both Cox-2 up-regulation and PGI(2) synthesis; p38 MAPK was also involved in both processes while JNK inhibition only affected PGI(2) synthesis. Pertussis toxin (an inhibitor of Galphai/Galphao proteins) prevented MAPK activation and inhibited both Cox-2 up-regulation and PGI(2) release. Genistein (a tyrosine kinase inhibitor) inhibited PGI(2) release without affecting MAPK activation or Cox-2 up-regulation. Simvastatin (0.1-1 microM) increased HDL-induced PGI(2) release ( approximately 45% at 1 microM) but did not significantly modify early MAPK activation or Cox-2 expression. Simvastatin alone did not significantly affect PGI(2) release. Our results suggest that mechanisms associated with G protein-coupled receptor activation, trigger Cox-2 up-regulation and PGI(2) release via multiple MAPK signalling pathways in VSMC. The mechanism is independent of tyrosine kinase receptors, although cytosolic tyrosine kinases could activate Cox-2 post-translationally. The potential contribution of HDL to vascular homeostasis, via increases in PGI(2) synthesis, could be enhanced by HMG-CoA reductase inhibitors.

Noncholesterol-lowering effects of statins

Statins, 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitors, inhibit the rate-limiting enzyme in cholesterol synthesis and lead to a significant reduction of plasma lipid concentrations. As a clear correlation exists between serum cholesterol and cardiovascular risk, statins have become increasingly important in current preventive medicine. Studies prompted by the extraordinary benefits afforded by these drugs have reported minimal changes in the vasculature of hypercholesterolemic patients when compared with clinical benefits and have led to further investigations to determine the underlying reasons for these clinical benefits. The purpose of this review is to present the wide array of systems that HMG-CoA reductase inhibitors are known to influence, which range from adverse events due to coronary artery disease, stroke risk, platelet function, endothelial function, and inflammatory effects to intracellular signaling pathways that control vascular cell migration, proliferation, and differentiation.

Experimental and interventional dietary study in humans on the role of HDL fatty acid composition in PGI2 release and Cox-2 expression by VSMC

BACKGROUND

High-density lipoproteins (HDLs) induce prostacyclin (PGI2) release in vascular smooth muscle cells (VSMCs) by up-regulation of cyclooxygenase-2 (Cox-2). Our goal was to analyze the role of human HDL lipid moiety on Cox-2-dependent PGI2 synthesis in human VSMCs and to assess the impact that the intake of diets with different fatty acid composition exert on HDL-induced PGI2 release.

MATERIALS AND METHODS

Human VSMCs were treated with HDL or fatty acids in the presence or absence of different cell signalling inhibitors and PGI2 (by enzyme immunoassay) and Cox-2 protein levels (by Western blot) were analyzed. High-density lipoproteins were obtained from a plasma pool or from plasma of 12 volunteers subjected to a longitudinal dietary interventional study of three consecutive diets periods enriched in monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids n-6 (PUFA n-6) or n-3 (PUFA n-3).

RESULTS

High-density lipoprotein delipidation attenuated the effect of HDL on both PGI2 synthesis and Cox-2 up-regulation, while arachidonic acid (AA) but not other fatty acids mimicked the effects of HDL. Arachidonic acid induced PGI2 synthesis and Cox-2 expression through similar mechanisms to those activated by HDL [pertussis toxin-sensitive G proteins, p42/44 mitogen-activated protein kinase (MAPK), p38MAPK, and c-Jun N-terminal kinase-1 (JNK-1) pathways]. Finally, we observed that HDL from the PUFA n-3 dietary period induced lower PGI2 release than that from the PUFA n-6 period (64% vs. 100%).

CONCLUSIONS

Our results suggest that lipid moiety modulates HDL-induced PGI2 release/Cox-2 up-regulation in human VSMCs, and that changes in fatty acids as accomplished with the diet can modulate vascular PGI2 homeostasis.

Beyond lipid-lowering: effects of statins on endothelial nitric oxide

Endothelial dysfunction is now recognised as an important process in the pathogenesis of atherosclerosis. Nitric oxide (NO) release by the endothelium regulates blood flow, inflammation and platelet aggregation, and consequently its disruption during endothelial dysfunction can decrease plaque stability and encourage the formation of atherosclerotic lesions and thrombi. Inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (statins) are often utilised in the prevention of coronary heart disease due to their efficacy at lowering lipid levels. However, statins may also prevent atherosclerotic disease by non-lipid or pleiotropic effects, for example, improving endothelial function by promoting the production of NO. There are various mechanisms whereby statins may alter NO release, such as inhibiting the production of mevalonate and important isoprenoid intermediates, thereby preventing the isoprenylation of the small GTPase Rho, which negatively regulates the expression of endothelial nitric oxide synthase (eNOS). Furthermore, statins may also increase eNOS activity via post-translational activation of the phosphatidylinositol 3-kinase/protein kinase Akt (PI3 K/Akt) pathway and/or through an interaction with the molecular chaperone heat-shock protein 90 (HSP90). Data suggest that statins may vary in their efficacy for enhancing the release of NO, and the mechanisms dictating these differences are not yet clear. By increasing NO production, statins may interfere with atherosclerotic lesion development, stabilise plaque, inhibit platelet aggregation, improve blood flow and protect against ischaemia. Therefore, the ability of statins to improve endothelial function through the release of NO may partially account for their beneficial effects at reducing the incidence of cardiovascular events.

Differential intracellular trafficking of von Willebrand factor (vWF) and vWF propeptide in porcine endothelial cells lacking Weibel-Palade bodies and in human endothelial cells

Von Willebrand factor (vWF) is an adhesive protein involved in primary haemostasis virtually absent in the thoracic aorta of swine, an animal model widely used in thrombosis and atherosclerosis. By RT-PCR analysis we show that porcine aortic endothelial cells (PAEC) express the vWF gene, although vWF mRNA levels were 8+/-0.8-fold (p<0.05) or 290+/-8.9-fold (p<0.0001) lower than those in porcine pulmonary artery EC (PPEC) or human aortic EC (HAEC), respectively. Although vWF was rare in the thoracic aorta of swine, vWF propeptide (vWFpp) was present in the endothelium of this artery and in both primary and passaged PAEC. In addition, vWFpp but not vWF was detected in PAEC by Western blot. In PAEC neither vWFpp nor P-selectin immunostaining depicted Weibel-Palade bodies (WPB)-like structures, and acute stimuli (alpha-thrombin or the calcium ionophore A23187) did not increase vWF secretion. vWFpp co-localized with a Golgi marker, that cycles between the stacked Golgi (SG fraction) and earlier compartments of the secretory pathway. Our results confirm that PAEC express very low levels of vWF mRNA and indicate that in these cells, that do not have WPB, vWF and vWFpp have divergent intracellular trafficking pathways.

Atorvastatin, administered at the onset of reperfusion, and independent of lipid lowering, protects the myocardium by up-regulating a pro-survival pathway

OBJECTIVES

The purpose of this study was to determine whether atorvastatin, a 3-hydroxy-3-methylglutaryl (HMG)-co-enzyme A (CoA) reductase inhibitor, limits myocardial necrosis when administered as an adjunct to reperfusion.

BACKGROUND

Statins inhibit HMG-CoA reductase to reduce the synthesis of cholesterol. However, it is proposed that statins have cardiovascular effects beyond their ability to lower cholesterol, possibly via recruitment of phosphatidyl inositol 3-kinase (PI3K) and the serine/threonine kinase, Akt. This signaling pathway has recently been linked to growth factor-mediated reperfusion salvage.

METHODS

Isolated perfused mouse hearts were subjected to 35 min of global ischemia and reperfused for 30 min in the presence of incremental concentrations of atorvastatin. Infarct size was determined by triphenyltetrazolium chloride staining, and the activity of the PI3K signaling cascade was determined by Western blot analysis.

RESULTS

We found that there was a profound dose-dependent reduction of infarct size with atorvastatin in the range of 25 to 100 micromol/l (optimal protection was seen at 50 micromol/l with infarct size of 16 +/- 2% vs. control, 33 +/- 2%, p < 0.01). Moreover, this protection was sensitive to inhibition with the PI3 kinase inhibitor, wortmannin, and was absent in endothelial nitric oxide synthase (eNOS) knockout mice. Western blot analysis revealed that atorvastatin resulted in rapid activation of the PI3K/Akt signaling cascade (within 5 min) and that both Akt and eNOS phosphorylation were significantly increased by 4.1-fold and 2.9-fold, respectively (p < 0.01). Moreover, phosphorylation of the PI3K substrates was abrogated by the administration of wortmannin.

CONCLUSIONS

Atorvastatin attenuates lethal reperfusion-induced injury in a manner that is reliant on PI3K and Akt activity and the presence and activity of eNOS.

Molecular mechanisms involved in the regulation of the endothelial nitric oxide synthase

The endothelial nitric oxide synthase (eNOS), the expression of which is regulated by a range of transcriptional and posttranscriptional mechanisms, generates nitric oxide (NO) in response to a number of stimuli. The physiologically most important determinants for the continuous generation of NO and thus the regulation of local blood flow are fluid shear stress and pulsatile stretch. Although eNOS activity is coupled to changes in endothelial cell Ca(2+) levels, an increase in Ca(2+) alone is not sufficient to affect enzyme activity because the binding of calmodulin (CaM) and the flow of electrons from the reductase to the oxygenase domain of the enzyme is dependent on protein phosphorylation and dephosphorylation. Two amino acids seem to be particularly important in regulating eNOS activity and these are a serine residue in the reductase domain (Ser(1177)) and a threonine residue (Thr(495)) located within the CaM-binding domain. Simultaneous alterations in the phosphorylation of Ser(1177) and Thr(495) in response to a variety of stimuli are regulated by a number of kinases and phosphatases that continuously associate with and dissociate from the eNOS signaling complex. eNOS associated proteins, such as caveolin, heat shock protein 90, eNOS interacting protein, and possibly also motor proteins provide the scaffold for the formation of the protein complex as well as its intracellular localization.