Atorvastatin reduces platelet-oxidized-LDL receptor expression in hypercholesterolaemic patients

Seven days of statin treatment improves nitric-oxide mediated endothelial-dependent cutaneous microvascular function in women with endometriosis

INTRODUCTION

Endometriosis is associated with systemic inflammation and increased risk of cardiovascular disease (CVD). Endothelial dysfunction is one of the first manifestations of CVD but is unexplored in women with endometriosis. HMG-CoA-reductase inhibitors (statins) exert potent anti-inflammatory effects, and have been proposed as an adjunctive therapy in women with endometriosis. We hypothesized that microvascular endothelial function would be impaired in otherwise healthy women with endometriosis mediated by reduced nitric oxide (NO)-dependent dilation and that short term statin administration would improve endothelial function.

METHODS

In 8 healthy control (HC: 33 ± 9 yr) and 8 women with endometriosis (EN: 34 ± 9 yr), laser-Doppler flux (LDF) was measured continuously during graded intradermal microdialysis perfusion of the endothelium-dependent agonist acetylcholine (Ach: 10-10-10-1 M) alone and in combination with the NO synthase inhibitor (L-NAME: 0.015 M). 6 EN repeated the microdialysis experiment following 7 days of oral atorvastatin treatment (10 mg). Cutaneous vascular conductance was calculated (CVC = LDF*mmHg-1) and normalized to site-specific maximum (28 mM sodium nitroprusside, 43 °C). The NO-dependent dilation was calculated as the difference between the areas under the dose response curves.

RESULTS

Ach-induced vasodilation was blunted in women with endometriosis (main effect p < 0.01), indicating impaired endothelial function. NO-dependent vasodilation was also reduced in women with endometriosis (HC: 217 ± 120.3 AUC vs. EN: 88 ± 97 AUC, p = 0.03). Oral atorvastatin improved Ach-induced (main effect p < 0.01) and NO-dependent (295 ± 153 AUC; p = 0.05) vasodilation in women with endometriosis.

CONCLUSION

Microcirculatory endothelium-dependent vasodilation is impaired in women with endometriosis, mediated in part by reductions in NO. Short-term oral atorvastatin improved endothelium-dependent vasodilation, suggesting that statin therapy may be a viable intervention strategy to mitigate accelerated CVD risk in women with endometriosis.

Independent association of Lp(a) with platelet reactivity in subjects without statins or antiplatelet agents

The physiological effect of Lp(a) on platelet activity is unclear. Previous studies explored the relationship between Lp(a) and platelet aggregation in patients taking statins and antiplatelet agents, but few was conducted in individuals without the bias of those drugs that either influence Lp(a) or platelet activity. The aim of this study was to assess the relationship between Lp(a) levels and platelet aggregation in subjects not taking statins or antiplatelet drugs. A hospital-based cross-sectional study was conducted to investigate the independent contribution of Lp(a) to platelet activity by controlling the effects of potential confounding factors including lipoprotein-associated phospholipase A2 [Lp-PLA2]. Blood samples were collected from 92 subjects without statins or antiplatelet agents from the Second Xiangya Hospital. The univariate correlation analysis showed a significant correlation between AA-induced average aggregation rate [AAR] and ApoB (r = 0.324, P = 0.002), ApoA1 (r = 0.252, P = 0.015), Lp(a) (r = 0.370, P < 0.001), Lp-PLA2 (r = 0.233, P = 0.025) and platelet counts [PLT] (r = 0.389, P < 0.001). Multivariate regression analysis suggested that Lp(a) contributed independently to AA-induced average aggregation rate (β = 0.023, P = 0.027) after controlling for the effects of ApoB, Lp-PLA2 and platelet counts. Lp(a) is positively associated with platelet aggregation independent of Lp-PLA2, which may partly account for the atherothrombotic effect of Lp(a).

Biochemistry and Nanomechanical Properties of Human Colon Cells upon Simvastatin, Lovastatin, and Mevastatin Supplementations: Raman Imaging and AFM Studies

One of the most important areas of medical science is oncology, which is responsible for both the diagnostics and treatment of cancer diseases. Over the years, there has been an intensive development of cancer diagnostics and treatment. This paper shows the comparison of normal (CCD-18Co) and cancerous (CaCo-2) cell lines of the human gastrointestinal tract on the basis of nanomechanical and biochemical properties to obtain information on cancer biomarkers useful in oncological diagnostics. The research techniques used were Raman spectroscopy and imaging and atomic force microscopy (AFM). In addition, the studies also included the effect of the statin compounds—mevastatin, lovastatin, and simvastatin—and their influence on biochemical and nanomechanical changes of cell properties using Raman imaging and AFM techniques. The cytotoxicity of statins was determined using XTT tests.

Oxidised Low-Density Lipoprotein-Induced Platelet Hyperactivity—Receptors and Signalling Mechanisms

Dyslipidaemia leads to proatherogenic oxidative lipid stress that promotes vascular inflammation and thrombosis, the pathologies that underpin myocardial infarction, stroke, and deep vein thrombosis. These prothrombotic states are driven, at least in part, by platelet hyperactivity, and they are concurrent with the appearancxe of oxidatively modified low-density lipoproteins (LDL) in the circulation. Modified LDL are heterogenous in nature but, in a general sense, constitute a prototype circulating transporter for a plethora of oxidised lipid epitopes that act as danger-associated molecular patterns. It is well-established that oxidatively modified LDL promote platelet activation and arterial thrombosis through a number of constitutively expressed scavenger receptors, which transduce atherogenic lipid stress to a complex array of proactivatory signalling pathways in the platelets. Stimulation of these signalling events underlie the ability of modified LDL to induce platelet activation and blunt platelet inhibitory pathways, as well as promote platelet-mediated coagulation. Accumulating evidence from patients at risk of arterial thrombosis and experimental animal models of disease suggest that oxidised LDL represents a tangible link between the dyslipidaemic environment and increased platelet activation. The aim of this review is to summarise recent advances in our understanding of the pro-thrombotic signalling events induced in platelets by modified LDL ligation, describe the contribution of individual platelet scavenger receptors, and highlight potential future challenges of targeting these pathways.

Endothelial Dysfunction in Chronic Kidney Disease, from Biology to Clinical Outcomes: A 2020 Update

The vascular endothelium is a dynamic, functionally complex organ, modulating multiple biological processes, including vascular tone and permeability, inflammatory responses, thrombosis, and angiogenesis. Endothelial dysfunction is a threat to the integrity of the vascular system, and it is pivotal in the pathogenesis of atherosclerosis and cardiovascular disease. Reduced nitric oxide (NO) bioavailability is a hallmark of chronic kidney disease (CKD), with this disturbance being almost universal in patients who reach the most advanced phase of CKD, end-stage kidney disease (ESKD). Low NO bioavailability in CKD depends on several mechanisms affecting the expression and the activity of endothelial NO synthase (eNOS). Accumulation of endogenous inhibitors of eNOS, inflammation and oxidative stress, advanced glycosylation products (AGEs), bone mineral balance disorders encompassing hyperphosphatemia, high levels of the phosphaturic hormone fibroblast growth factor 23 (FGF23), and low levels of the active form of vitamin D (1,25 vitamin D) and the anti-ageing vasculoprotective factor Klotho all impinge upon NO bioavailability and are critical to endothelial dysfunction in CKD. Wide-ranging multivariate interventions are needed to counter endothelial dysfunction in CKD, an alteration triggering arterial disease and cardiovascular complications in this high-risk population.

Statins reduce vascular inflammation in atherogenesis: A review of underlying molecular mechanisms

Chronic inflammation enhances the detrimental role of dyslipidaemia during atherogenesis. Statins are among the most effective anti-atherosclerotic medications, being able to impact on both cardiovascular morbidity and mortality. Although these molecules have been first described as lipid-lowering medications, several lines of evidence suggest additional benefits through their "pleiotropic" anti-atherosclerotic activities. Specifically, statins can modulate vascular atherosclerotic inflammation by directly improving functions of endothelial cells, vascular smooth muscle cells, platelets, and immune cells. Here, we discuss basic and clinical evidence to provide an update on the molecular mechanisms underlying the protective anti-inflammatory role of statins in atherogenesis.

The effect of HMG-CoA reductase inhibitors on thrombolysis-induced haemorrhagic transformation

Thrombolysis-induced haemorrhagic transformation is the most challenging preventable complication in thrombolytic therapy. This condition is often associated with poor functional outcome and long-term disease burden. Statins, or 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, are controversially suggested to either increase or decrease the odds of better primary outcomes compared to treatment without statins after thrombolysis in patients or animals; statins are thought to act by influencing lipid levels, the inflammatory response, blood brain barrier permeability and cell apoptosis. Statins are the cornerstone of secondary prevention of cardiovascular and cerebrovascular diseases. However, the role of statins in acute phase stroke, and the necessity of their use, remains unclear. Currently, whether statins can increase the risk of haemorrhagic transformation is of great concern for patients treated with tissue plasminogen activator (t-PA). Herein, we thoroughly summarize the recent advances that address whether the administration of statins in ischaemic stroke increases haemorrhagic transformation in patients or animals who received thrombolysis at an early stage and the related mechanisms. This review will provide more clinical and preclinical evidence to address questions regarding the exercise of caution in the use of high dose statins in patients who received thrombolysis and if low dose statins may be beneficial in decreasing thrombolysis-induced haemorrhagic transformation.

Statins, haemostatic factors and thrombotic risk

PURPOSE OF REVIEW

Statins reduce cholesterol synthesis and promote low-density lipoprotein clearance from circulation. Beyond their cholesterol-lowering action, statins may interfere with haemostasis. This review aims to provide an update on the impact of statin treatment on markers of haemostasis and platelet function and on thrombosis-related outcomes.

RECENT FINDINGS

Different coagulation factors are modulated by statins, leading to inhibition of coagulation and increased fibrinolysis. Also, an impact of statins on platelet function has been documented. From a clinical perspective, several observational studies have revealed a reduced incidence of venous thromboembolism in patients receiving statins, which has been argued in some available studies and meta-analyses. Furthermore, a beneficial effect of early statin initiation following acute coronary syndrome for short-term prevention of thrombosis-related events has been documented, but the available data are still not consistent.

SUMMARY

Although statins influence the levels of a multitude of haemostatic factors in an antithrombotic direction, data supporting their use for venous thromboembolism prevention are not consistent, and the impact of statins on early vascular events following acute coronary syndrome is still debated. Whether the robust long-term beneficial effects of statins in reducing cardiovascular risk may be also explained by persistent changes in haemostatic factors needs further exploration.

Association between statin use and plasma D-dimer levels

D-dimers, specific breakdown fragments of cross-linked fibrin, are generally used as circulating markers of activated coagulation. Statins influence haemostatic factors, but their effect on plasma D-dimer levels is controversial. Therefore, the aim of this meta-analysis was to evaluate the association between statin therapy and plasma D-dimer levels. We searched PubMed, Web of Science, Cochrane Library, Scopus and EMBASE (up to September 25, 2014) to identify randomised controlled trials (RCTs) investigating the impact of statin therapy on plasma D-dimer levels. Two independent reviewers extracted data on study characteristics, methods and outcomes. Meta-analysis of data from nine RCTs with 1,165 participants showed a significant effect of statin therapy in reducing plasma D-dimer levels (standardised mean difference [SMD]: –0.988 µg/ml, 95 % confidence interval [CI]: –1.590 – –0.385, p=0.001). The effect size was robust in sensitivity analysis and omission of no single study significantly changed the overall estimated effect size. In the subgroup analysis, the effect of statins on plasma D-dimer levels was significant only in the subsets of studies with treatment duration ≥ 12 weeks (SMD: –0.761 µg/ml, 95 %CI: –1.163– –0.360; p< 0.001), and for lipophilic statins (atorvastatin and simvastatin) (SMD: –1.364 µg/ml, 95 % CI: –2.202– –0.526; p=0.001). Hydrophilic statins (pravastatin and rosuvastatin) did not significantly reduce plasma D-dimer levels (SMD: –0.237 µg/ml, 95 %CI: –1.140–0.665, p=0.606). This meta-analysis of RCTs suggests a decrease of plasma D-dimer levels after three months of statin therapy, and especially after treatment with lipophilic statins. Well-designed trials are required to validate these results.

Note: The review process for this paper was fully handled by Christian Weber, Editor in Chief.

Contribution of lectin-like oxidized low-density lipoprotein receptor-1 and LOX-1 modulating compounds to vascular diseases

The lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is the major receptor for binding and uptake of oxidized low-density lipoprotein (oxLDL) in endothelial cells. LOX-1 is also expressed in macrophages, smooth muscle cells and platelets. Following internalization of oxLDL, LOX-1 initiates a vicious cycle from activation of pro-inflammatory signaling pathways, thus promoting an increased reactive oxygen species formation and secretion of pro-inflammatory cytokines. LOX-1 plays a pivotal role in the development of endothelial dysfunction, foam cell and advanced lesions formation as well as in myocardial ischemia. Furthermore, it is known that LOX-1 plays a pivotal role in mitochondrial DNA damage, vascular cell apoptosis, and autophagy. A large number of studies provide evidence of a LOX-1's role in endothelial dysfunction, hypertension, diabetes, and obesity. In addition, novel insights into LOX-1 ligands and the activated signaling pathways have been gained. Recent studies have shown an interaction of LOX-1 with microRNA's, thus providing novel tools to regulate LOX-1 function. Because LOX-1 is increased in atherosclerotic plaques and contributes to endothelial dysfunction, several compounds were tested in vivo and in vitro to modulate the LOX-1 expression in therapeutic approaches.

Platelet tissue factor activity and membrane cholesterol are increased in hypercholesterolemia and normalized by rosuvastatin, but not by atorvastatin

BACKGROUND AND AIMS

High plasma LDL-cholesterol (LDL-C) and platelet responses have major pathogenic roles in atherothrombosis. Thus, statins and anti-platelet drugs constitute mainstays in cardiovascular prevention/treatment. However, the role of platelet tissue factor-dependent procoagulant activity (TF-PCA) has remained unexplored in hypercholesterolemia. We aimed to study platelet TF-PCA and its relationship with membrane cholesterol in vitro and in 45 hypercholesterolemic patients (HC-patients) (LDL-C >3.37 mmol/L, 130 mg/dL) and 37 control subjects (LDL-C <3.37 mmol/L). The effect of 1-month administration of 80 mg/day atorvastatin (n = 21) and 20 mg/day rosuvastatin (n = 24) was compared.

METHODS

Platelet TF-PCA was induced by GPIbα activation with VWF-ristocetin.

RESULTS

Cholesterol-enriched platelets in vitro had augmented aggregation/secretion and platelet FXa generation (1.65-fold increase, p = 0.01). HC-patients had 1.5-, 2.3- and 2.5-fold increases in platelet cholesterol, TF protein and activity, respectively; their platelets had neither hyper-aggregation nor endogenous thrombin generation (ETP). Rosuvastatin, but not atorvastatin, normalized platelet cholesterol, TF protein and FXa generation. It also increased slightly the plasma HDL-C levels, which correlated negatively with TF-PCA.

CONCLUSIONS

Platelets from HC-patients were not hyper-responsive to low concentrations of classical agonists and had normal PRP-ETP, before and after statin administration. However, washed platelets from HC-patients had increased membrane cholesterol, TF protein and TF-PCA. The platelet TF-dependent PCA was specifically expressed after VWF-induced GPIbα activation. Rosuvastatin, but not atorvastatin treatment, normalized the membrane cholesterol, TF protein and TF-PCA in HC-patients, possibly unveiling a new pleiotropic effect of rosuvastatin. Modulation of platelet TF-PCA may become a novel target to prevent/treat atherothrombosis without increasing bleeding risks.

The Role of CD36 in the Effect of Arginine in Atherosclerotic Rats

Background

The aim of this study was to investigate the effects of arginine in the development of atherosclerosis in rats fed a high-fat diet supplemented with arginine and to evaluate the role of CD36 in this process.

Material/Methods

A total of 40 Sprague-Dawley rats were randomly assigned to 4 groups: control group, fat diet group, simvastatin group, and arginine group. They were fed for 12 weeks and were then sacrificed. Immunohistochemical CD36 expression and pathology was investigated in the aorta; CD36 expression in mononuclear cells was detected by Western blot and RT-PCR.

Results

The thickness of the aortal intima, media, and I/M significantly decreased in the arginine group rats compared with those in the fat diet group (P<0.05). CD36 expression was up-regulated in rats in the fat diet group compared with the control group and was down-regulated in rats in the arginine group compared with rats in the fat diet group.

Conclusions

The addition of arginine has a significant effect on reducing rat atherosclerosis development, which may be attributed to both the down-regulation of CD36 expression in rat aortic endothelial and blood mononuclear cells and the NO pathway.

Atorvastatin protects cardiomyocytes from oxidative stress by inhibiting LOX-1 expression and cardiomyocyte apoptosis

Coronary artery disease (CAD) is a major health problem worldwide. The most severe form of CAD is acute coronary syndrome (ACS). Recent studies have demonstrated the beneficial role of atorvastatin in ACS; however, the mechanisms underlying this effect have not been fully clarified. Growing evidence indicates that activation of the lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) plays an important role in oxidative stress-induced cardiomyocyte apoptosis during ACS. In this study, we examined whether atorvastatin inhibits H2O2-induced LOX-1 expression and H9c2 cardiomyocyte apoptosis, and investigated the underlying signaling pathway. Treatment of H9c2 cardiomyocytes with H2O2 resulted in elevated expression of LOX-1 mRNA and protein, as well as increased caspase-3 and -9 protein expression and cell apoptosis. H2O2-induced LOX-1 expression, caspase protein expression, and cardiomyocyte apoptosis were attenuated by pretreatment with atorvastatin. Atorvastatin activated H2O2-inhibited phosphorylation of Akt in a concentration-dependent manner. The Akt inhibitor, LY294002, inhibited the effect of atorvastatin on inducing Akt phosphorylation and on suppressing H2O2-mediated caspase up-regulation and cell apoptosis. These findings indicate that atorvastatin protects cardiomyocyte from oxidative stress via inhibition of LOX-1 expression and apoptosis, and that activation of H2O2-inhibited phosphorylation of Akt may play an important role in the protective function of atorvastatin.

Platelets, acting in part via P-selectin, mediate cytomegalovirus-induced microvascular dysfunction

Cytomegalovirus (CMV) infects a majority of the population worldwide. It has been implicated in cardiovascular disease, induces microvascular dysfunction, and synergizes with hypercholesterolemia to promote leukocyte and platelet recruitment in venules. Although platelets and platelet-associated P-selectin contribute to cardiovascular disease inflammation, their role in CMV-induced vascular responses is unknown. We assessed the role of platelets in CMV-induced microvascular dysfunction by depleting platelets and developing bone marrow chimeric mice deficient in platelet P-selectin. Wild-type and chimeric mice received mock or murine (m)CMV intraperitoneally. Five weeks later, some mice were switched to a high-cholesterol diet (HC) to investigate the synergism between mCMV and HC. Arteriolar vasodilation and recruitment of leukocytes and donor platelets in venules were measured at 11wk. mCMV with or without HC caused significant endothelial dysfunction in arterioles. Platelet depletion restored normal vasodilation in mCMV-HC but not mCMV-ND mice, whereas protection was seen in both groups for platelet P-selectin chimeras. Only mCMV + HC elevated leukocyte and platelet recruitment in venules. Leukocyte adhesion was reduced to mock levels by acute platelet depletion but was only partially decreased in platelet P-selectin chimeras. Platelets from mCMV-HC mice and, to a lesser extent, mCMV-ND but not mock-HC mice showed significant adhesion in mCMV-HC recipients. Our findings implicate a role for platelets, acting through P-selectin, in CMV-induced arteriolar dysfunction and suggest that the addition of HC leads to a platelet-dependent, inflammatory infiltrate that is only partly platelet P-selectin dependent. CMV appeared to have a stronger activating influence than HC on platelets and may represent an additional therapeutic target in vulnerable patients.

Pravastatin and simvastatin improves acetylsalicylic acid-mediated in vitro blood platelet inhibition

BACKGROUND

Insight into the pathophysiology of atherothrombosis indicates that an integrated risk factor approach, focusing particularly on the management of dyslipidaemia (with statins) and thrombosis (with ASA), may constitute an optimal therapeutic approach. We investigated whether pravastatin, simvastatin and atorvastatin may directly modulate under in vitro conditions the reactivity of blood platelets originating from healthy volunteers. In addition, we analysed the influence of statins on the platelet sensitivity to ASA under such conditions.

MATERIALS AND METHODS

We monitored collagen- or ADP-induced platelet aggregation, CD36, PAC-1 and CD62 expression on platelet surface and thromboxane generation after incubation with pravastatin, simvastatin, atorvastatin and/or ASA.

RESULTS

The incubation of whole blood with simvastatin and pravastatin significantly decreased CD36 expression. In the presence of 50 μM ASA, simvastatin and pravastatin significantly reduced the PAC-1 expression (30% reduction for simvastatin, P < 0·01, and 15% reduction for pravastatin, P < 0·01), platelet aggregation (20% reduction for both statins, P < 0·01) and thromboxane generation (35% reduction for simvastatin, P < 0·001, and 30% reduction for pravastatin, P < 0·001) compared to ASA alone. Atorvastatin changed neither baseline platelet aggregation nor ASA-mediated platelet inhibition.

CONCLUSIONS

Our results suggested that statins may directly interact with platelet membranes or may modulate a signalling pathway in platelets (the pleiotropic effects of statins). It is possible that the statin effect on CD36 and ASA-mediated protein acetylation can be reached by the modulation of a distribution or a function of membrane-associated proteins. Further studies are certainly needed to better elucidate the mechanism(s) underlying the statins' effects on platelet sensitivity to ASA.

Statins as anti-inflammatory agents in atherogenesis: molecular mechanisms and lessons from the recent clinical trials

Ample evidence exists in support of the potent anti-inflammatory properties of statins. In cell studies and animal models statins exert beneficial cardiovascular effects. By inhibiting intracellular isoprenoids formation, statins suppress vascular and myocardial inflammation, favorably modulate vascular and myocardial redox state and improve nitric oxide bioavailability. Randomized clinical trials have demonstrated that further to their lipid lowering effects, statins are useful in the primary and secondary prevention of coronary heart disease (CHD) due to their anti-inflammatory potential. The landmark JUPITER trial suggested that in subjects without CHD, suppression of low-grade inflammation by statins improves clinical outcome. However, recent trials have failed to document any clinical benefit with statins in high risk groups, such in heart failure or chronic kidney disease patients. In this review, we aim to summarize the existing evidence on statins as an anti-inflammatory agent in atherogenesis. We describe the molecular mechanisms responsible for the anti-inflammatory effects of statins, as well as clinical data on the non lipid-lowering, anti-inflammatory effects of statins on cardiovascular outcomes. Lastly, the controversy of the recent large randomized clinical trials and the issue of statin withdrawal are also discussed.

Pharmacological actions of statins: a critical appraisal in the management of cancer

Statins, among the most commonly prescribed drugs worldwide, are cholesterol-lowering agents used to manage and prevent cardiovascular and coronary heart diseases. Recently, a multifaceted action in different physiological and pathological conditions has been also proposed for statins, beyond anti-inflammation and neuroprotection. Statins have been shown to act through cholesterol-dependent and -independent mechanisms and are able to affect several tissue functions and modulate specific signal transduction pathways that could account for statin pleiotropic effects. Typically, statins are prescribed in middle-aged or elderly patients in a therapeutic regimen covering a long life span during which metabolic processes, aging, and concomitant novel diseases, including cancer, could occur. In this context, safety, toxicity, interaction with other drugs, and the state of health have to be taken into account in subjects treated with statins. Some evidence has shown a dichotomous effect of statins with either cancer-inhibiting or -promoting effects. To date, clinical trials failed to demonstrate a reduced cancer occurrence in statin users and no sufficient data are available to define the long-term effects of statin use over a period of 10 years. Moreover, results from clinical trials performed to evaluate the therapeutic efficacy of statins in cancer did not suggest statin use as chemotherapeutic or adjuvant agents. Here, we reviewed the pharmacology of the statins, providing a comprehensive update of the current knowledge of their effects on tissues, biological processes, and pathological conditions, and we dissected the disappointing evidence on the possible future use of statin-based drugs in cancer therapy.

Synthesis and structure-activity relationship of N-(2-arylethyl) isoquinoline derivatives as human scavenger receptor CD36 antagonists

By using human scavenger receptor CD36 as the target, twenty-five N-(2-arylethyl) isoquinoline derivatives were designed, synthesized and evaluated for their antagonistic activities for CD36-oxidatively low density lipoprotein (oxLDL) binding. The primary analysis of structure-activity relationship (SAR) indicated a methoxyl at the 7-position and a hydroxyl at the 6- or 8-position could afford good activities. Among these analogs, compounds 7e and 7t showed the potential CD36 antagonistic activities with IC(50) values of 0.2 and 0.8 μg/mL, respectively. Furthermore, both of them could effectively inhibit oxLDL uptake in insect Sf9 cells overexpressing human CD36, and thus have been selected for further investigation. We consider N-(2-arylethyl) isoquinoline analogs to be a family of novel CD36 antagonists.

Effects of atorvastatin and rosuvastatin on thromboxane-dependent platelet activation and oxidative stress in hypercholesterolemia

OBJECTIVES

We examined the time-dependent effects of atorvastatin and rosuvastatin on in vivo oxidative stress and platelet activation, to assess whether these phenomena are related to any pleiotropic effect of any statin or to their LDL-lowering effect. We also asked whether the presence of specific allele frequencies in carriers of the 3'UTR/lectin-like oxidized LDL receptor-1 (LOX-1) polymorphism may influence the effect of either statin.

METHODS

We included 60 hypercholesterolemic subjects, previously screened for LOX-1 3'UTR polymorphism, randomized, according to genetic profile (15 T and 15 C carriers for each arm), to atorvastatin 20mg/day or rosuvastatin 10mg/day.

RESULTS

After 8 weeks, atorvastatin and rosuvastatin were associated with comparable, significant reductions in LDL cholesterol (40.8% and 43.6%, respectively), plasma hs-CRP (9.5% vs. 13.8%), urinary 11-dehydro-thromboxane (TX) B(2) (38.9% vs. 27.1%) and 8-iso-prostaglandin (PG) F(2α) (39.4% vs. 19.4%). The impact of rosuvastatin or atorvastatin on CRP, 8-iso-PGF(2α), and 11-dehydro-TXB(2) did not differ according to the LOX-1 haplotype. On multiple regression analyses, only CRP and LDL were independent predictors of 11-dehydro-TXB(2), and only LDL was a significant predictor of 8-iso-PGF(2α).

CONCLUSIONS

Both atorvastatin and rosuvastatin cause comparable reductions of thromboxane-dependent platelet activation, lipid peroxidation and inflammation. The presence of 3'UTR/LOX-1 polymorphism does not affect the changes induced by either statin.

Serum soluble CD36, assessed by a novel monoclonal antibody-based sandwich ELISA, predicts cardiovascular mortality in dialysis patients

AIM

Accelerated atherosclerosis is a characteristic feature of chronic kidney disease (CKD). CD36 is a scavenger receptor which contributes to foam cell formation, an early crucial step in atherosclerosis development. Recently, a soluble form of CD36 (sCD36) has been discovered. The aim of the study was to develop an ELISA method for quantitative sCD36 evaluation and to measure it in a cohort of CKD stage 5 patients.

METHOD

A novel monoclonal antibody-based sandwich ELISA for sCD36 evaluation was developed and verified by repeated optimization procedures. Serum concentration of sCD36 was then analyzed in a cohort of 228 CKD stage 5 patients prior to dialysis initiation. Additionally, samples from a control group of 73 healthy, age and gender-matched subjects were evaluated.

RESULTS

The novel CD36 ELISA assay had a recovery of at least 90%, and intra- and inter-assay variability of 6 and 11%, respectively. Concentration of serum sCD36 in CKD patients was significantly increased as compared to controls, and associated with the use of HMG-CoA reductase inhibitors (statins) and the presence of diabetes mellitus (DM). Patients above the 75th percentile of sCD36 concentration were at increased risk of 3-year cardiovascular mortality, as compared to the rest of the cohort [HR 2.85 (1.09-7.59) p=0.03].

CONCLUSION

For the first time, sCD36 was assessed quantitatively in a group of patients and showed associations with DM, CKD, and statin use. Furthermore, the concentration of sCD36 predicted cardiovascular mortality in CKD stage 5 patients.

Atorvastatin induces associated reductions in platelet P-selectin, oxidized low-density lipoprotein, and interleukin-6 in patients with coronary artery diseases

The development and progression of atherosclerosis comprises various processes, such as endothelial dysfunction, chronic inflammation, thrombus formation, and lipid profile modification. Statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors that have pleiotropic effects in addition to cholesterol-lowering properties. However, the mechanisms of these effects are not completely understood. Here, we investigated whether atorvastatin affects the levels of malondialdehyde-modified low-density lipoprotein (MDALDL), an oxidized LDL, the proinflammatory cytokine interleukin-6 (IL-6), or platelet P-selectin, a marker of platelet activation, relative to that of LDL cholesterol (LDL-C). Forty-eight patients with coronary artery disease and hyperlipidemia were separated into two groups that were administered with (atorvastatin group) or without (control group) atorvastatin. The baseline MDA-LDL level in all participants significantly correlated with LDL-C (r = 0.71, P < 0.01) and apolipoprotein B levels (r = 0.66, P < 0.01). Atorvastatin (10 mg/day) significantly reduced the LDL-C level within 4 weeks and persisted for a further 8 weeks of administration. Atorvastatin also reduced the MDA-LDL level within 4 weeks and further reduced it over the next 8 weeks. Platelet P-selectin expression did not change until 4 weeks of administration and then significantly decreased at 12 weeks, whereas the IL-6 level was gradually, but not significantly, reduced at 12 weeks. In contrast, none of these parameters significantly changed in the control group within these time frames. The reduction (%) in IL-6 between 4 and 12 weeks after atorvastatin administration significantly correlated with that of MDALDL and of platelet P-selectin (r = 0.65, P < 0.05 and r = 0.70, P < 0.05, respectively). These results suggested that the positive effects of atorvastatin on the LDL-C oxidation, platelet activation and inflammation that are involved in atherosclerotic processes are exerted in concert after lowering LDL-C.

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

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

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

WHAT THIS STUDY ADDS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Molecular basis of human CD36 gene mutations

CD36 is a transmembrane glycoprotein of the class B scavenger receptor family. The CD36 gene is located on chromosome 7 q11.2 and is encoded by 15 exons. Defective CD36 is a likely candidate gene for impaired fatty acid metabolism, glucose intolerance, atherosclerosis, arterial hypertension, diabetes, cardiomyopathy, Alzheimer disease, and modification of the clinical course of malaria. Contradictory data concerning the effects of antiatherosclerotic drugs on CD36 expression indicate that further investigation of the role of CD36 in the development of atherosclerosis may be important for the prevention and treatment of this disease. This review summarizes current knowledge of CD36 gene structure, splicing, and mutations and the molecular, metabolic, and clinical consequences of these phenomena.

Molecular basis of human CD36 gene mutations

CD36 is a transmembrane glycoprotein of the class B scavenger receptor family. The CD36 gene is located on chromosome 7 q11.2 and is encoded by 15 exons. Defective CD36 is a likely candidate gene for impaired fatty acid metabolism, glucose intolerance, atherosclerosis, arterial hypertension, diabetes, cardiomyopathy, Alzheimer disease, and modification of the clinical course of malaria. Contradictory data concerning the effects of antiatherosclerotic drugs on CD36 expression indicate that further investigation of the role of CD36 in the development of atherosclerosis may be important for the prevention and treatment of this disease. This review summarizes current knowledge of CD36 gene structure, splicing, and mutations and the molecular, metabolic, and clinical consequences of these phenomena.

Lectin-like oxidized low-density lipoprotein receptor-1, a new promising target for the therapy of atherosclerosis?

Endothelial activation and dysfunction induced by oxidized modified low-density lipoprotein (ox-LDL) is one of the key steps in the initiation of atherosclerosis. Recent studies have shown that a new lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) mediates the recognition and internalization of ox-LDL. LOX-1 is the main receptor for ox-LDL and may play an important role in the pathogenesis of hypertension, diabetes, and, especially, of atherosclerosis. The potential role of LOX-1 in the pathogenesis of atherosclerosis includes: endocytosis of ox-LDL, expression co-location with atherosclerosis enhanced by atherosclerosis-related risk factors, elevated LOX-1 protein in cardiovascular disease, effects related to atherosclerosis and eliminated by antiatherosclerotic drugs. Identification and regulation of LOX-1 and understanding its signal transduction pathways might improve our insight toward the pathogenesis of atherosclerosis and provide a selective treatment approach. LOX-1 might be a potential and promising target for the development of novel antiatherosclerotic drugs. However, due to limited knowledge about LOX-1, there are still many questions to be answered.

Lectin-like oxidized-LDL receptor-1 (LOX-1) polymorphisms influence cardiovascular events rate during statin treatment

BACKGROUND

Oxidized-LDL (ox-LDL) are involved in atherothrombosis by induction of endothelial dysfunction and thrombosis. The specific receptor lectin-like oxidized-LDL receptor-1 (LOX-1) is expressed in endothelial cells, monocytes and platelets. LOX-1 gene allelic variants (3'UTR/T) have been related with cardiovascular events and reduced anti-platelet activity induced by statins.

OBJECTIVES

To detect whether LOX-1 polymorphisms could affect statins effectiveness in cardiovascular prevention.

PATIENTS/METHODS

The present was a retrospective study performed in 751 white hypercholesterolemic subjects treated with increasing doses of atorvastatin (n=382, 247 male, 135 female) or simvastatin (n=369, 244 male, 125 female) up to 4 years, whose LDL target was 3.36 mmol/L according to the National Cholesterol Education Program, Adult Treatment Panel III (NCEP-ATPIII). Single nucleotide polymorphism were evaluated by allelic discrimination assays (PCR), lipid profile by enzymatic-colorimetric methods and C-reactive protein (CRP) by a nephelometric technique.

RESULTS

Twenty-three non-ST elevation (NSTEMI) and eleven ST-elevation myocardial infarction (STEMI) were encountered in the observational period without differences between treatments (p=0.175) and sex (p=0.139). Each symptomatic subject (10 reaching the appropriate LDL target and 24 with still undesirable LDL) had the 3'UTR/T allelic variant (adjusted O.R. 4.63, 95% C.I. 3.46-6.70, p<0.0001). Among patients not reaching LDL target the C allele resulted protective with respect to T carriers (p<0.00001). Also, similar changes of CRP resulted in different event rate between T and C carriers (p<0.001) in the whole cohort.

CONCLUSIONS

In the studied population LOX-1 genetic variants influence cardiovascular risk reduction induced by statins also in patients not reaching the LDL target. The previously described LOX-1-related antithrombotic actions of both statins employed could have a specific role in what observed, suggesting a genetic influence in statins LDL-lowering partially related actions.

Modulation of ADP-induced platelet activation by aspirin and pravastatin: role of lectin-like oxidized low-density lipoprotein receptor-1, nitric oxide, oxidative stress, and inside-out integrin signaling

Lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (LOX-1), a receptor for oxidized-LDL, is up-regulated in activated endothelial cells, and it plays a role in atherothrombosis. However, its role in platelet aggregation is unclear. Both aspirin and HMG CoA reductase inhibitors (statins) reduce LOX-1 expression in endothelial cells. In this study, we investigated the effect of aspirin and pravastatin on LOX-1 expression on plate-lets. After ADP stimulation, mean fluorescence intensity of LOX-1 expression on platelets increased 1.5- to 2.0-fold. Blocking LOX-1 inhibited ADP-induced platelet aggregation in a concentration- and time-dependent manner. We also established that LOX-1 is important for ADP-stimulated inside-out activation of platelet alpha(IIb)beta(3) and alpha(2)beta(1) integrins (fibrinogen receptors). The specificity of this interaction was determined by arginine-glycine-aspartate-peptide inhibition. Furthermore, we found that LOX-1 inhibition of integrin activation is mediated by inhibition of protein kinase C activity. In other experiments, treatment with aspirin (1-10 mM) and pravastatin (1-5 microM) reduced platelet LOX-1 expression, with a synergistic effect of the combination of aspirin and pravastatin. Aspirin and pravastatin both reduced reactive oxygen species (ROS) released by activated platelets measured as malonyldialdehyde (MDA) release and nitrate/nitrite ratio. Aspirin and pravastatin also enhanced nitric oxide (NO) release measured as nitrite/nitrite + nitrate (NOx) ratio in platelet supernates. Small concentrations of aspirin and pravastatin had a synergistic effect on the inhibition of MDA release and enhancement of nitrite/NOx. Thus, LOX-1 is important for ADP-mediated platelet integrin activation, possibly through protein kinase C activation. Furthermore, aspirin and pravastatin inhibit LOX-1 expression on platelets in part by favorably affecting ROS and NO release from activated platelets.

CD36: implications in cardiovascular disease

CD36 is a broadly expressed membrane glycoprotein that acts as a facilitator of fatty acid uptake, a signaling molecule, and a receptor for a wide range of ligands, including apoptotic cells, modified forms of low density lipoprotein, thrombospondins, fibrillar beta-amyloid, components of Gram positive bacterial walls and malaria infected erythrocytes. CD36 expression on macrophages, dendritic and endothelial cells, and in tissues including muscle, heart, and fat, suggest diverse roles, and indeed, this is truly a multi-functional receptor involved in both homeostatic and pathological conditions. Despite an impressive increase in our knowledge of CD36 functions, in depth understanding of the mechanistic aspects of this protein remains elusive. This review focuses on CD36 in cardiovascular disease-what we know, and what we have yet to learn.

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 in the treatment of polycythaemia vera and allied disorders: An antithrombotic and cytoreductive potential?

Thrombohaemorrhagic complications are major clinical problems in the classical chronic Ph-negative myeloproliferative disorders (CMPDs), polycytaemia vera (PV), essential thrombocythaemia (ET) and idiopathic myelofibrosis (IMF), contributing significantly to morbidity and mortality. Pathophysiologically these disorders are characterized by clonal myeloproliferation, myeloaccumulation and a propensity to develop myelofibrosis and neoangiogenesis in both the bone marrow and spleen. Based upon in vitro and in vivo studies of the effects of statins (antithrombotic, antiproliferative, proapoptotic and antiangiogenic), this review focuses on the translation of these effects into potential clinical benefits of statin therapy in patients with CMPDs.