Interactions of platelets, macrophages, and lipoproteins in hypercholesterolemia: antiatherogenic effects of HMG-CoA reductase inhibitor therapy

Potential Benefits and Risks Associated with the Use of Statins

HMG-CoA reductase inhibitors, commonly known as statins, are the primary treatment choice for cardiovascular diseases, which stand as the leading global cause of mortality. Statins also offer various pleiotropic effects, including improved endothelial function, anti-inflammatory properties, reduced oxidative stress, anti-thrombotic effects, and the stabilization of atherosclerotic plaques. However, the usage of statins can be accompanied by a range of adverse effects, such as the development of type 2 diabetes mellitus, muscular symptoms, liver toxicity, kidney diseases, cataracts, hemorrhagic strokes, and psychiatric complications. These issues are referred to as statin-associated symptoms (SAS) and are relatively infrequent in clinical trials, making it challenging to attribute them to statin use definitively. Therefore, these symptoms can lead to significant problems, necessitating dose adjustments or discontinuation of statin therapy. This review aims to provide a comprehensive overview of the mechanism of action, potential advantages, and associated risks of statin utilization in clinical settings.

Understanding the molecular mechanisms of statin pleiotropic effects

Statins represent the cornerstone of pharmacotherapy for the prevention of atherosclerotic cardiovascular disease. These medications not only reduce low-density lipoprotein cholesterol (LDL-C) via inhibition of 3-hydroxy-3-methylglutarate attached to CoA reductase, the key rate-limiting step in the cholesterol biosynthetic pathway, but also upregulate expression of the low-density lipoprotein receptor, improving serum clearance. Given LDL-C is a causal risk factor for the development of atherosclerosis, these complementary mechanisms largely explain why statin therapy leads to reductions in major adverse cardiovascular events. However, decades of basic and clinical research have suggested that statins may exert other effects independent of LDL-C lowering, termed pleiotropic effects, which have become a topic of debate among the scientific community. While some literature suggests statins may improve plaque stability, reduce inflammation and thrombosis, decrease oxidative stress, and improve endothelial function and vascular tone, other studies have suggested potential harmful pleiotropic effects related to increased risk of muscle-related side effects, diabetes, hemorrhagic stroke, and cognitive decline. Furthermore, the introduction of newer, non-statin LDL-C lowering therapies, including ezetimibe, proprotein convertase subtilisin/Kexin Type 9, and bempedoic acid, have challenged the statin pleiotropy theory. This review aims to provide a historical background on the development of statins, explore the mechanistic underpinnings of statin pleiotropy, review the available literature, and provide up to date examples that suggest statins may exert effects outside of LDL-C lowering and the cardiovascular system.

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.

A Review of Red Yeast Rice, a Traditional Fermented Food in Japan and East Asia: Its Characteristic Ingredients and Application in the Maintenance and Improvement of Health in Lipid Metabolism and the Circulatory System

Red yeast rice has been used to produce alcoholic beverages and various fermented foods in China and Korea since ancient times; it has also been used to produce tofuyo (Okinawan-style fermented tofu) in Japan since the 18th century. Recently, monacolin K (lovastatin) which has cholesterol-lowering effects, was found in some strains of Monascus fungi. Since statins have been used world-wide as a cholesterol-lowering agent, processed foods containing natural statins are drawing attention as materials for primary prevention of life-style related diseases. In recent years, large-scale commercial production of red yeast rice using traditional solid-state fermentation has become possible, and various useful materials, including a variety of monascus pigments (polyketides) that spread as natural pigments, in addition to statins, are produced in the fermentation process. Red yeast rice has a lot of potential as a medicinal food. In this paper, we describe the history of red yeast rice as food, especially in Japan and East Asia, its production methods, use, and the ingredients with pharmacological activity. We then review evidence of the beneficial effects of red yeast rice in improving lipid metabolism and the circulatory system and its safety as a functional food.

Influence of Simvastatin on Aspects of Thrombogenesis in CAPD Patients

← Background

Patients on continuous ambulatory peritoneal dialysis (CAPD) are prone to dyslipidemia and have a high risk of cardiovascular death. Statins show beneficial effects on serum lipids and thrombogenesis in various groups of patients, but prospective studies have so far not been performed on CAPD patients.

← Aim

To determine the effects of 6 month's treatment with simvastatin on platelet function and some hemostatic parameters, markers of endothelial cell injury, in 14 CAPD patients with hypercholesterolemia.

← Methods

Simvastatin was given in a dose of 10 mg at bedtime. Commercially available kits were used for all determinations.

← Results

Cholesterol and low density lipoprotein fell significantly as early as after 1 month of the therapy ( p < 0.001). Platelet aggregation in whole blood and plateletrich plasma was transiently decreased by simvastatin therapy. The fibrinolytic activity index increased significantly after 6 months of simvastatin administration ( p < 0.05), reaching values observed in the control group, whereas euglobulin clot lysis time, which was also significantly shortened after 6 months ( p < 0.05), did not reach values obtained in healthy volunteers. Vascular cell adhesion molecule, thrombomodulin, and protein Z decreased significantly after 3 months of the therapy ( p < 0.05, p < 0.05, and p < 0.01, respectively), whereas intercellular adhesion molecule decreased after 6 months ( p < 0.05). Vascular endothelial growth factor and its receptor, protein Z, total tissue factor pathway inhibitor (TFPI), TFPI/Xa complexes, and thrombin activatable fibrinolysis inhibitor concentration and activity fell significantly after 6 months of treatment with simvastatin (all p < 0.05). Tissue plasminogen activator concentration increased after 1 month ( p < 0.01 after 1 month, p < 0.05 after 3 and 6 months), whereas total homocysteine fell after 6 months of simvastatin therapy ( p < 0.05). Truncated TFPI decreased significantly as early as after 1 month of therapy ( p < 0.05 after 1 month, p < 0.01 after 3 and 6 months).

← Conclusion

Simvastatin is an effective hypolipemic agent in CAPD patients. It favorably affects platelet aggregation and the extrinsic coagulation pathway, improves fibrinolysis, and ameliorates endothelial dysfunction. Simvastatin might reduce the risk of thrombotic complications in CAPD patients.

Selected pharmacotherapy agents as antiproliferative and anti-inflammatory compounds

The repurposing of safe therapeutic drugs has emerged as an alternative approach to rapidly identify effective, safe, and conveniently available therapeutics to treat/prevent cancer. Therefore, it was hypothesized that acidic chelator drugs could have a genuine potential as antiproliferative agents. Based on their pKa, the selected 15 acidic drugs of eight classes-namely sulfonylureas, proton pump inhibitors, fluoroquinolones, nonsteroidal anti-inflammatory agents, thiazolidinediones, thienopyridines, statins, and nicotinic acid-were assayed for anticancer HTS against the lung A549, skin A375, breast MCF7 and T47D, pancreatic PANC1, cervical HeLa, and leukemia K562 cancer cell lines and normal fibroblasts. Lipopolysaccharide-prompted inflammation in RAW264.7 macrophages was the potential anticancer mechanism. Atorvastatin exerted remarkably superior cytotoxicity against A375.2S (IC50 value 0.02 μM p < .001 vs. cisplatin 0.07 μM IC50 value). Atorvastatin exhibited an equipotency to cisplatin's T47D growth inhibition (34.6 μM vs. 34.59 μM; p > .05). Levofloxacin as well as ciprofloxacin superbly superseded the antineoplastic cisplatin activity against the K562 cell line (respective IC50 values [μM] 10.4 and 19.5 vs. 29.3; p < .05-<.01). Gemifloxacin and lansoprazole had comparable antiproliferation in K562 to cisplatin's (respective IC50 values [μM] 34.9 and 36.3 vs. 29.3; p > .05). The selected agents lacked cytotoxicity in the panel of MCF7, HeLa, A549, or Panc1 cancer cells. Most notably, LPS prompted RAW264.7 macrophages, atorvastatin, piroxicam, clopidogrel, esomeprazole, and lansoprazole were of higher anti-inflammation potency than indomethacin (p < .01-.001). Evidently, omeprazole, pioglitazone, gemifloxacin, and indomethacin were of comparable anti-inflammation potencies (p > .05). Collectively, this work reveals acidic chelator drugs (atorvastatin, gemifloxacin, and lansoprazole with dual anti-inflammation and antiproliferation propensities) as authentic agents for the repurposing approach in anticancer chemotherapy/prevention.

Effect of statin treatment on circulating malondialdehyde concentrations: a systematic review and meta-analysis

Background

The effect of statins on oxidative stress markers, such as malondialdehyde (MDA), is still a matter of debate. We sought to address this issue by conducting a systematic review and meta-analysis of published data on the effect of statin treatment on systemic MDA concentrations.

Methods

A literature search was conducted on MEDLINE/PubMed, ISI Web of Sciences and Scopus. Data were pooled using a random-effects model.

Results

A total of 35 studies assessing MDA concentrations before and after statin treatment in 1512 participants (mean age 53.6 years, 48.7% males) were identified. Extreme between-study heterogeneity was observed (I² = 96.0%, p < 0.001). Pooled standardized mean difference (SMD) showed a significant reduction in plasma MDA concentrations after treatment (SMD = -1.47 µmol/l, 95% confidence interval = -1.89 to -1.05 μmol/l; p < 0.001). Similarly, a subgroup analysis of 10 studies that also included a placebo group showed a significant reduction in plasma MDA concentrations with statins (-1.03 μmol/l, 95% confidence interval = -1.52 to -0.29 μmol/l; p = 0.036).

Conclusions

This systematic review and meta-analysis showed that statin treatment significantly reduces systemic MDA concentrations. However, the results should be interpreted with caution because of extreme between-study heterogeneity, which warrants further intervention studies.

Interaction of statins with phospholipid bilayers studied by solid-state NMR spectroscopy

Statins are drugs that specifically inhibit the enzyme HMG-CoA reductase and thereby reduce the concentration of low-density lipoprotein cholesterol, which represents a well-established risk factor for the development of atherosclerosis. The results of several clinical trials have shown that there are important intermolecular differences responsible for the broader pharmacologic actions of statins, even beyond HMG-CoA reductase inhibition. According to one hypothesis, the biological effects exerted by these compounds depend on their localization in the cellular membrane. The aim of the current work was to study the interactions of different statins with phospholipid membranes and to investigate their influence on the membrane structure and dynamics using various solid-state NMR techniques. Using ¹H NOESY MAS NMR, it was shown that atorvastatin, cerivastatin, fluvastatin, rosuvastatin, and some percentage of pravastatin intercalate the lipid-water interface of POPC membranes to different degrees. Based on cross-relaxation rates, the different average distribution of the individual statins in the bilayer was determined quantitatively. Investigation of the influence of the investigated statins on membrane structure revealed that lovastatin had the least effect on lipid packing and chain order, pravastatin significantly lowered lipid chain order, while the other statins slightly decreased lipid chain order parameters mostly in the middle segments of the phospholipid chains.

Foam cell formation: A new target for fighting atherosclerosis and cardiovascular disease

During atherosclerosis, the gradual accumulation of lipids into the subendothelial space of damaged arteries results in several lipid modification processes followed by macrophage uptake in the arterial wall. The way in which these modified lipoproteins are dealt with determines the likelihood of cholesterol accumulation within the monocyte-derived macrophage and thus its transformation into the foam cell that makes up the characteristic fatty streak observed in the early stages of atherosclerosis. The unique expression of chemokine receptors and cellular adhesion molecules expressed on the cell surface of monocytes points to a particular extravasation route that they can take to gain entry into atherosclerotic site, in order to undergo differentiation into the phagocytic macrophage. Indeed several GWAS and animal studies have identified key genes and proteins required for monocyte recruitment as well cholesterol handling involving lipid uptake, cholesterol esterification and cholesterol efflux. A re-examination of the previously accepted paradigm of macrophage foam cell origin has been called into question by recent studies demonstrating shared expression of scavenger receptors, cholesterol transporters and pro-inflammatory cytokine release by alternative cell types present in the neointima, namely; endothelial cells, vascular smooth muscle cells and stem/progenitor cells. Thus, therapeutic targets aimed at a more heterogeneous foam cell population with shared functions, such as enhanced protease activity, and signalling pathways, mediated by non-coding RNA molecules, may provide greater therapeutic outcome in patients. Finally, studies targeting each aspect of foam cell formation and death using both genetic knock down and pharmacological inhibition have provided researchers with a clearer understanding of the cellular processes at play, as well as helped researchers to identify key molecular targets, which may hold significant therapeutic potential in the future.

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.

Increased Mean Platelet Volume in Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is a genetic disorder of lipoprotein metabolism and increases the risk of premature cardiovascular diseases. In patients with FH, platelet function may be activated; however, the extent of this activation and its etiology are unclear. We aimed to evaluate the mean platelet volume (MPV), a marker of platelet activation, in patients with FH. The study group consisted of 164 patients with FH and 160 control patients. Controls were matched for age, gender, hypertension, and smoking. The MPV was significantly higher in patients with FH than in controls (9.2 ± 0.4 vs 7.9 ± 0.6 fL, respectively; P < .001). Platelet count was significantly lower among patients with FH when compared to control patients (259 ± 51 vs 272 ± 56 × 103/L, respectively; P = .03). In linear regression analysis, MPV was independently associated only with total cholesterol (β = .6, 95% confidence interval: 0.004-0.008, P < .001). We have shown that MPV was increased in patients with FH and that it was independently associated with total cholesterol level.

Platelets in inflammation: regulation of leukocyte activities and vascular repair

There is now a large body of evidence that platelets are central actors of inflammatory reactions. Indeed, platelets play a significant role in a variety of inflammatory diseases. These diseases include conditions as varied as atherosclerosis, arthritis, dermatitis, glomerulonephritis, or acute lung injury. In this context, one can note that inflammation is a convenient but imprecise catch-all term that is used to cover a wide range of situations. Therefore, when discussing the role of platelets in inflammation, it is important to clearly define the pathophysiological context and the exact stage of the reaction. Inflammatory reactions are indeed multistep processes that can be either acute or chronic, and their sequence can vary greatly depending on the situation and organ concerned. Here, we focus on how platelets contribute to inflammatory reactions involving recruitment of neutrophils and/or macrophages. Specifically, we review past and recent data showing that platelets intervene at various stages of these reactions to regulate parameters such as endothelial permeability, the recruitment of neutrophils and macrophages and their effector functions, as well as inflammatory bleeding. The mechanisms underlying these various modulating effect of platelets are also discussed.

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.

HMG-CoA reductase inhibitors (statins), inflammation, and endothelial progenitor cells-New mechanistic insights of atherosclerosis

Statins have been shown to favorably affect the prognosis of patients with risk factors to atherosclerosis-both as a primary and a secondary prevention. The beneficial effects observed with statin therapy are not merely related to changes in lipid profile but also are due to a positive effect on vascular inflammation and on immune-modulation of T lymphocytes and endothelial progenitor stem cells (EPCs). This dual effect has been demonstrated mainly in clinical trials where a change in endothelial function was observed within hours, much earlier than the effects of statins on the lipid profile (weeks). Based on all the knowledge that we have today questions were raised as to the mechanistic pathways that may explain the process of atherosclerosis and through this pathway to find better solutions and therapies to prevent and fight atherosclerosis. Our review will focus on the new updates in the field of inflammation and stem cells in vascular biology-in relation with atherosclerosis.

Estimation of cell membrane properties and erythrocyte red-ox balance in patients with metabolic syndrome

Metabolic syndrome (MS) is associated with occurrence of the many cardiovascular risk factors such as atherogenic dyslipidemia, visceral fat distribution, arterial hypertension and pro-thrombotic and pro-inflammatory status. In our study the effect of disorders that appear in MS on red-ox balance and erythrocyte cell membrane properties were estimated. The study comprised 50 patients with diagnosed MS and in 25 healthy subjects. Content of thiobarbituric acid reactive substances (TBARS) and catalase, superoxide dismutase and glutathione peroxidase activity were estimated in red blood cells. Moreover, conformation status of membrane proteins, membrane fluidity and osmotic fragility were evaluated. MS was found to manifest: (1) the increase of the concentration of TBARS in erythrocytes with no statistically significant differences in antioxidant enzymes activity, (2) disorders in the structure of erythrocyte cytoskeleton proteins, (3) the increase in membrane lipids fluidity at the depth of 5th and 12th carbon atom of fatty acid hydrocarbon chain and significantly decreased fluidity at the depth of 16th carbon atom, (4) increased erythrocyte osmotic fragility.

The effect of a platelet cholesterol modulation on the acetylsalicylic acid-mediated blood platelet inhibition in hypercholesterolemic patients

Aspirin (acetylsalicylic acid, ASA) is widely used in the prevention of cardiovascular disease, but its beneficial effects may be restrained in some individuals, where the reduced ability of ASA to protect against arterial thrombotic events is observed. We analyzed the influence of the treatment with atorvastatin (10mg/day) on the platelet sensitivity to ASA monitored under in vitro conditions in hypercholesterolemic patients. The associations between plasma or platelet cholesterol parameters and the ASA-mediated inhibition of platelet reactivity or the extent of platelet protein acetylation by ASA were estimated in the patients treated with atorvastatin for 1, 3, or 6 months. Out of 27 patients, in 17 individuals platelets appeared significantly more sensitive to 50 μM ASA in arachidonic acid- or collagen-induced whole blood aggregation following 1 month atorvastatin therapy (inhibition by 60.9 ± 5.6% vs. 48.8 ± 5.4%, P<0.05 for 0.5mM arachidonic acid, 40.8 ± 2.9% vs. 27.0 ± 4.1%, P<0.05 for 1 μg/ml collagen), and this effect lasted for 3 and 6 months, remaining in a weak, although significant, relation to the reduction of platelet cholesterol content (R(S)=-0.277, P<0.002 for arachidonic acid, R(S)=-0.197, P<0.02 for collagen). It was, however, not dependent upon either antiplatelet action or plasma lipid-lowering activity of atorvastatin. In addition, in about 50% of patients, we noticed that ASA (50 μM) significantly and time-dependently diminished thromboxane B(2) concentration in atorvastatin-treated patients. The ASA-induced acetylation of platelet proteins significantly increased in the course of atorvastatin therapy and was associated with reduced platelet cholesterol (R(S)=-0.598, P<0.0001). In conclusion, statin therapy may improve platelet sensitivity to ASA in some hypercholesterolemic patients. This effect may extend beyond the action of atorvastatin as merely a lipid-lowering agent. The mechanisms of resistance of some patients to such a combined ASA-statin treatment remain to be elucidated.

Basic Science Review: Statin Therapy-Part I: The Pleiotropic Effects of Statins in Cardiovascular Disease

3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG CoA-reductase) inhibitors, otherwise known as statins, are currently the medical treatment of choice for hypercholesterolemia. Hypercholesterolemia is a known risk factor for cardiovascular disease, and statin therapy has led to a significant reduction in morbidity and mortality from adverse cardiac events, stroke, and peripheral arterial disease. In addition to achieving a therapeutic decrease in serum cholesterol levels, statin therapy appears to promote other effects that are independent of changes in serum cholesterol. These ‘‘pleiotropic’’ effects include attenuation of vascular inflammation, improved endothelial cell function, stabilization of atherosclerotic plaque, decreased vascular smooth muscle cell migration and proliferation, and inhibition of platelet aggregation. This article is part I of a 2-part review, and it focuses on the pleiotropic effects of statins at the cellular level.

Anti-inflammatory and hypolipemic effects in vitro of simvastatin comparing to epicatechin in patients with type-2 hypercholesterolemia

OBJECTIVE

The study involved 25 patients with type-2 hypercholesterolemia (mean age 49.3+/-11.3). The control group consisted of 28 healthy individuals (mean age 50.7+/-7.2).

METHODS

The cholesterol concentrations in plasma membranes of erythrocytes were measured by means of Liebermann-Burchard reagent. The membrane lipid peroxidation in whole erythrocytes was determined. The membrane fluidity was estimated by spin labelled method.

RESULTS

The in vitro study shows that the cholesterol concentration in membranes incubated with simvastatin and epicatechin decreases; in healthy donors there are no changes. Simvastatin does not lead to changes in the lipid peroxidation in the in vitro data. Epicatechin decreases the level of membrane lipid peroxidation in patients with hypercholesterolemia and in healthy donors. Simvastatin and epicatechin cause an increase in the fluidity of plasma membranes of erythrocytes.

CONCLUSIONS

Simvastatin causes the decrease in cholesterol concentration in erythrocytes membranes not only in the in vivo but also the in vitro experiments. Flavonoids have antioxidant properties in vitro. Simvastatin influences the lipid peroxidation only in vivo, not in vitro systems. This observation is an additional contribution to the statins' pleiotropic effect.

The effect of rosuvastatin treatment on the mean platelet volume in patients with uncontrolled primary dyslipidemia with hypolipidemic diet treatment

Platelet activation and aggregation are central processes in the pathophysiology of coronary heart disease. Mean platelet volume (MPV), a determinant of platelet activation, is a newly emerging risk marker for atherothrombosis. Rosuvastatin, a new hydrophilic 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin), is approved as an adjunct to diet in patients with dyslipidemia. In this study, we evaluated the effects of rosuvastatin on the MPV levels in patients with uncontrolled primary dyslipidemia with hypolipidemic treatment. We selected 30 age, sex and body mass index matched patients with uncontrolled primary dyslipidemia and hypolipidemic diet treatment and 30 normolipidemic healthy subjects. Dyslipidemic patients were treated with 10 mg/day rosuvastatin for 12 weeks. Metabolic parameters and MPV were measured at baseline and after rosuvastatin treatment in dyslipidemic group. At baseline, the dyslipidemic group had significantly higher MPV levels than in the healthy control group (8.4 +/-1.2 fl vs. 8.1 +/-0 1.0 fl, p < 0.005). The level of MPV decreased significantly after rosuvastatin treatment from a mean of 8.4 +/- 1.2 fl to 8.1 +/- 1.3 fl, (p < 0.001). The changes in MPV levels with rosuvastatin treatment were not correlated to changes in plasma lipids (p > 0.05). In addition to its well-known hypolipidemic effect, rosuvastatin also possesses significant anti-platelet activation properties. This antiplatelet effect of rosuvastatin treatment could play a role in reducing cardiovascular complications in primary hyperlipidemic patients.

Korean red ginseng attenuates hypercholesterolemia-enhanced platelet aggregation through suppression of diacylglycerol liberation in high-cholesterol-diet-fed rabbits

Intake of Korean red ginseng (KRG, ginseng Radix rubra), rich in glycosylated saponins (ginsenosides), has been known to inhibit platelet aggregation in the normocholesterolemic condition. However, it is unclear whether KRG can attenuate hypercholesterolemia-enhanced platelet aggregation. This study examined whether the daily consumption of a KRG-water extract (WE) could prevent the hypercholesterolemia-enhanced platelet aggregation and progression of hypercholesterolemic atherosclerosis. KRG-WE administration (200 mg/kg/day) for 8 weeks potently inhibited the platelet aggregation induced by low doses of agonists (0.5 microg/mL collagen and 0.025 unit/mL thrombin), whereas it weakly reduced the blood-cholesterol levels and formation of atheromatous lesions. In further investigation, KRG-WE significantly suppressed collagen-induced 1,2-diacylglycerol liberation, but had no significant effect on arachidonic acid liberation. Taken together, it can be suggested that the antiplatelet effect of KRG-WE may, at least partly, be due to the inhibition of 1,2-diacylglycerol generation rather than regulation of blood lipid levels. In conclusion, daily consumption of KRG-WE could be a useful alternative measure for the prevention of thrombus and atheroma formation in hypercholesterolemia.

Statin Therapy for Vascular Failure

There is increasing evidence that statins reduce cardiovascular events such as coronary artery disease or stroke in hypercholesterolemic patients in both primary and secondary prevention. The striking benefit achieved with statin treatments in patients with a wide range of cholesterol levels cannot be attributed to their cholesterol lowering effect alone. Substantial data has recently accumulated showing that statins exert various effects on multiple targets, namely pleiotropic effects, especially targeting the concept of 'vascular failure', including the improvement of vascular endothelial function, inhibition of vascular smooth muscle cell proliferation and migration, anti-inflammatory actions, anti-oxidative effects or stabilization of vulnerable plaques. These effects have potential in the treatments of coronary artery disease in various settings, such as prevention of its onset as well as its progression, or plaque rupture. Statin therapy should be more extensively applied even in normolipidemic patients if there are additional risk factors such as hypertension, diabetes mellitus, or others. Furthermore, statins may be used to intervene in earlier stage risk conditions such as postprandial hyperlipidemia or hyperglycemia, insulin resistant state, masked hypertension, or metabolic syndrome to further reduce mortality or morbidity of coronary artery disease and heart failure.

Ongoing clinical trials of the pleiotropic effects of statins

BACKGROUND

The multiple effects (ie, pleiotropic effects of statins) have received increasing recognition and may have clinical applicability across a broad range of cardiovascular and noncardiovascular conditions.

OBJECTIVE

To determine the relevance and significance of ongoing clinical trials of the pleiotropic effects of statins, focusing on nonlipid effects.

METHOD

Ongoing trials were identified through personal communication, reports presented at scientific meetings (2000-2004), and queries made to AstraZeneca, Bristol-Myers Squibb Co, Merck & Co, Novartis, and Pfizer, manufacturers of the currently marketed statins. Published trials and other source material were identified through electronic searches on MEDLINE (1990-2003), abstract books, and references identified from bibliographies of pertinent articles. Eligible studies were the clinical trials of statins currently under way in which primary or secondary outcomes included the statins' nonlipid (ie, pleiotropic) effect(s). Data were extracted and trial quality was assessed by the authors.

RESULTS

Of the 22 ongoing trials of the nonlipid effects of statins identified, 10 assessed inflammatory markers and plaque stabilization, 4 assessed oxidized low density lipoprotein/vascular oxidant stress, 3 assessed end-stage renal disease, 3 assessed fibrinogen/viscosity, 2 assessed endothelial function, 2 assessed acute coronary syndrome, 2 assessed aortic stenosis progression, and 1 each assessed hypertension, osteoporosis, ischemic burden, Alzheimer's disease, multiple sclerosis, and stroke (outcomes often overlapped).

CONCLUSION

Given the excellent safety and tolerability of statins as a class, full exploration of their pleiotropic effects has the potential to provide additional benefits to many patients.

[Platelet activation and hypercholesterolemia in the pathogenesis of deep vein thrombosis]

Currently it is accepted that deep vein thrombosis is a multifactorial event in which the presence of activated platelets and also plasmatic lipids seems to play a pivotal role that it is not well established in the scientific bibliography. Due to the non consensus state about these topics between the different groups working in these aspects, the topic involving deep vein thrombosis-platelets-lipids, and also their interactions, still is an interesting area of investigation, in which it is necessary to carry out studies with the aim of establishing risk factors, initial diagnostic methods and clinical assays to probe the efficacy of new therapies.

Statin use and survival in patients with chronic heart failure — results from two observational studies with 5200 patients

BACKGROUND

There is minimal evidence that HMG-CoA reductase inhibitors (statins) are beneficial in patients with chronic heart failure (CHF). Treatment with statins may lead to a lower mortality in CHF, independent of cholesterol levels, CHF etiology and clinical status.

METHODS

In a first study, we included 3132 patients with CHF from the ELITE 2 study in whom information on body mass index (BMI) and statin use at baseline were available. In a second study, we pooled the databases of 5 tertiary referral centers with 2068 CHF patients. In this cohort 705 patients were on a statin (34%), 585 of 1202 (49%) patients with ischemic etiology, and 120 of 866 (14%) patients with non-ischemic etiology (established by coronary angiography).

FINDINGS

Patients in ELITE 2 who received statin therapy at baseline (n=397, 13%) had lower mortality (hazard ratio [HR] 0.61, 95% CI 0.45-0.83; p=0.0007). In univariate analysis, increasing age, NYHA class, creatinine, and decreasing BMI, LVEF, and cholesterol, as well as lack of beta-blocker treatment and ischemic etiology (all p<0.002) related to higher mortality. In multivariable analysis, statin therapy related to lower mortality independently of all these variables (adjusted HR 0.66, 95% CI 0.47-0.93; p=0.017). In the second study CHF patients on statins had lower mortality (adjusted HR 0.58, 95% CI 0.44-0.77; p=0.0001). Both in patients with ischemic (p<0.0001) and non-ischemic etiology (p=0.028) statin treatment related to better survival.

INTERPRETATION

In chronic heart failure, treatment with statins is related to lower mortality, independent of cholesterol levels, disease etiology and clinical status.

Diabetes mellitus-associated atherosclerosis: mechanisms involved and potential for pharmacological invention

While diabetes mellitus is most often associated with hypertension, dyslipidemia, and obesity, these factors do not fully account for the increased burden of cardiovascular disease in patients with the disease. This strengthens the need for comprehensive studies investigating the underlying mechanisms mediating diabetic cardiovascular disease and, more specifically, diabetes-associated atherosclerosis. In addition to the recognized metabolic abnormalities associated with diabetes mellitus, upregulation of putative pathological pathways such as advanced glycation end products, the renin-angiotensin system, oxidative stress, and increased expression of growth factors and cytokines have been shown to play a causal role in atherosclerotic plaque formation and may explain the increased risk of macrovascular complications. This review discusses the methods used to assess the development of atherosclerosis in the clinic as well as addressing novel biomarkers of atherosclerosis, such as low-density lipoprotein receptor-1. Experimental models of diabetes-associated atherosclerosis are discussed, such as the streptozocin-induced diabetic apolipoprotein E knockout mouse. Results of major clinical trials with inhibitors of putative atherosclerotic pathways are presented. Other topics covered include the role of HMG-CoA reductase inhibitors and fibric acid derivatives with respect to their lipid-altering ability, as well as their emerging pleiotropic anti-atherogenic actions; the effect of inhibiting the renin-angiotensin system by either ACE inhibition or angiotensin II receptor antagonism; the effect of glycemic control and, in particular, the promising role of thiazolidinediones with respect to their direct anti-atherogenic actions; and newly emerging mediators of diabetes-associated atherosclerosis, such as advanced glycation end products, vascular endothelial growth factor and platelet-derived growth factor. Overall, this review aims to highlight the observation that various pathways, both independently and in concert, appear to contribute toward the pathology of diabetes-associated atherosclerosis. Furthermore, it reflects the need for combination therapy to combat this disease.

Effect of atorvastatin upon platelet activation in hypercholesterolemia, evaluated by flow cytometry

Hyperlipidemia is a well established risk factor for cardiovascular disease and atherothrombotic events, in which platelet activation also plays a significant role. However, very few studies have addressed platelet activation in hypercholesterolemia, the potential effect of lipid lowering drugs upon platelet hyperfunction, and the question of whether changes in the latter are correlated to normalization of plasma lipids. This study used whole blood flow cytometry to assess in vivo and in vitro platelet activation in a group of 33 patients with hypercholesterolemia, and also the ex vivo effect of atorvastatin (20 mg/day) upon such activation. A control group of 40 normolipidemic volunteers matched in terms of age, sex and added risk factors to the patient group was used. The results showed that hypercholesterolemic patients had in vivo a significantly greater percentage of GPIIb/IIIa- and phosphatidylserine-positive platelets compared with the control group (4.62+/-3.51% and 2.58+/-1.19% versus 2.73+/-1.08% and 1.54+/-0.68%, respectively). In vitro response of CD62 expression to thrombin was also greater in the patients than in the controls (92.51+/-6.00% versus 89.63+/-10.72%, p<0.05). Atorvastatin therapy normalized platelet hyperfunction in the patients studied and reduced GPIIb/IIIa response to ADP (from 82.65+/-6.43% to 75.84+/-4.89%, p<0.01). A significant correlation can be seen between such normalization and the decrease in plasma levels of total and LDL cholesterol.

Modulation of macrophage function and metabolism

Several drugs or pharmacologically active molecules such as statins, calcium antagonists, and PPAR agonists have been shown to affect macrophage functions that contribute to atherosclerosis and modulate plaque stability. For example, the modulation of matrix metalloproteinase secretion and cholesterol metabolism in macrophages may help to prevent cardiovascular disease independently of the correction of risk factors.

Beneficial cardiovascular pleiotropic effects of statins

Pleiotropic effects of a drug are actions other than those for which the agent was specifically developed. These effects may be related or unrelated to the primary mechanism of action of the drug, and they are usually unanticipated. Pleiotropic effects may be undesirable (such as side effects or toxicity), neutral, or, as is especially the case with HMG-CoA reductase inhibitors (statins), beneficial. Pleiotropic effects of statins include improvement of endothelial dysfunction, increased nitric oxide bioavailability, antioxidant properties, inhibition of inflammatory responses, and stabilization of atherosclerotic plaques. These and several other emergent properties could act in concert with the potent low-density lipoprotein cholesterol-lowering effects of statins to exert early as well as lasting cardiovascular protective effects. Understanding the pleiotropic effects of statins is important to optimize their use in treatment and prevention of cardiovascular disease.

The antioxidant effects of statins

Oxidative stress contributes to the initiation and the development of atherosclerotic plaques and adversely influences myocardial integrity. Statins interfere with oxidation in several ways that may contribute to reducing the atherogenic process. In addition to direct antioxidant effects, statins reduce circulating oxidized low-density lipoproteins (oxLDL) and inhibit their uptake by macrophages. They also reduce circulating markers of oxidation such as F2-isoprostane and nitrotyrosine. Statins inhibit oxidant enzymes activity such as that of reduced nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase and myeloperoxidase and up-regulate the activity of antioxidant enzymes such as catalase and paraoxonase. They reduce endothelial dysfunction mainly by their ability to enhance endothelial nitric oxide bioavailability, which is achieved by several mechanisms. The antioxidant properties of statins extend to organ protection especially the myocardium and the lungs.

[Non-lipid effects of statins: myth or fact?]

Hydroxy-methylglutaryl coenzyme A reductase-inhibitors (HMG-CoA [statins]) are currently the most effective method to pharmacologically decrease total plasma cholesterol levels. A number of multicenter studies have demonstrated, that statins administered for several years lead to a significant reduction of cardiovascular events and mortality compared with placebo. Apart from the well known LDL- and cholesterol lowering effect, statins have been postulated to exert beneficial effects on mortality due to so called 'non-lipid effects'. There is circumstantial evidence from a number of experimental studies that statins can improve endothelial function, exert anti-inflammatory and anti-oxidative effects, stabilize arteriosclerotic plaque and inhibit proliferation and activation of smooth muscle cells. However, the clinical implications of these beneficial 'non-lipid effects' are unclear, but appear to exert only a minor role in comparison to the lowering effect of statins on total plasma cholesterol levels.

Endothelial cell injury markers in chronic renal failure on conservative treatment and continuous ambulatory peritoneal dialysis

AIM

In chronic renal failure in dialyzed patients vascular damage is frequently observed and it is probable that disturbances in fibrinolytic activity and endothelial dysfunction may play a role in vascular complications such as stroke or ischemic heart disease. There have been a few data concerning hemostasis in chronic renal failure. Since hemostatic disturbances in nephrotic syndrome mimick those observed in patients maintained on chronic ambulatory peritoneal dialyses (CAPD), the aim of the study was to assess adhesion molecules (P-selectin, E-selectin, ICAM, VCAM and markers of endothelial cell injury), von Willebrand factor, thrombomodulin, and TFPI (tissue factor pathway inhibitor) in CAPD patients as well as in subjects with chronic renal failure (CRF) treated conservatively.

METHODS

The studies were performed on 23 CAPD patients, 24 patients with nephrotic syndrome and 24 sex- and age-matched healthy volunteers. TFPI total, full length, truncated, von Willebrand factor, trombomodulin, P-selectin, E-selectin, ICAM, VCAM and vascular endothelial growth factor (VEGF) and its receptor sFlt3 were assayed using commercially available kits. We evaluated also thrombin activity (thrombin-antithrombin complexes (TAT), prothrombin fragments 1 and 2) and the degree of plasmin generation.

RESULTS

In CAPD and CRF patients, concentrations of the adhesion molecules P-selectin, E-selectin, ICAM and VCAM were significantly higher when compared to the control group. Concentrations of total, free and truncated TFPI were significantly higher in CAPD and CRF patients when compared to the healthy volunteers. Concentrations of 'classical' markers of endothelial cell injury, von Willebrand factor and thrombomodulin, were significantly higher in CAPD and CRF patients when compared to the control group. In CAPD patients, VCAM and thrombomodulin were significantly elevated when compared to the CRF patients.

CONCLUSIONS

The elevated levels of adhesion molecules in CAPD patients probably reflect inadequate clearance as well as enhanced synthesis/release. They may also indicate endothelial cell injury as well as elevated levels of von Willebrand factor and trombomodulin and increased ICAM and VCAM in CAPD patients. Our studies indicate that in renal failure patients, particularly on CAPD, there is evidence of endothelial cell injury and a high degree of hypercoagulation relative to healthy subjects. It may lead to fibrin deposition in the vascular wall, thrombus formation, and development and progression of atherosclerosis with its complications.

A comparative study of the in vitro antioxidant activity of statins

BACKGROUND

Treatment of hypercholesterolemia with statins is remarkably effective in cardiovascular prevention. This has led to the hypothesis that these drugs may act on the atherosclerotic plaque by mechanism(s) independent of the reduction of serum cholesterol levels. The aim of this study was to assess the total antioxidant activity of the most prescribed statins: fluvastatin, atorvastatin, pravastatin and simvastatin.

METHODS

We measured the in vitro antioxidant activity of statins as their ability to antagonize the oxidation of alpha-keto-gamma-methiolbutyric acid by both hydroxyl and peroxyl radicals. The results are expressed as Total Oxyradical Scavenging Capacity (TOSC) units. Uric acid and Trolox were used as the reference antioxidants.

RESULTS

The scavenging capacity towards hydroxyl radicals was highest for simvastatin (3375+/-112 U/mg), a value 270.2% higher (P<0.0001) compared to uric acid (reference antioxidant vs. hydroxyl radicals, 1249+/-71 U/mg). Among the tested statins, fluvastatin exhibited the highest anti-peroxyl radical antioxidant capacity (8755+/-187 U/mg) which appeared 50% lower (P<0.0001) compared to Trolox (reference antioxidant vs. peroxyl radicals, 17460+/-379 U/mg).

CONCLUSIONS

All the statins tested have intrinsic antioxidant activity with both anti-hydroxyl and peroxyl radical activity. Simvastatin was the most effective as an anti-hydroxyl radical antioxidant and fluvastatin as an anti-peroxyl radical antioxidant.

Lovastatin extended release: a review of its use in the management of hypercholesterolaemia

Lovastatin extended release (ER) provides a new form of delivery for lovastatin, an HMG-CoA reductase inhibitor. Lovastatin ER delivers the drug in a more sustained fashion, as shown by a smoother plasma concentration-time profile, a lower maximum plasma concentration and a prolonged half-life compared with that of lovastatin immediate release (IR). At dosages of 10-60 mg/day, lovastatin ER significantly reduced levels of total cholesterol, low density lipoprotein (LDL)-cholesterol and triglycerides, and increased levels of high density lipoprotein-cholesterol, in patients with primary hypercholesterolaemia in a randomised, double-blind study of 12 weeks' duration. These effects were maintained in a 6-month extension study in which patients received lovastatin 40 or 60 mg/day. In a randomised 4-week study in 24 patients with primary hypercholesterolaemia, the reduction in plasma LDL-cholesterol levels was significantly greater with lovastatin ER 40 mg/day than with the IR formulation administered at the same dosage. Lovastatin ER was well tolerated in all studies and adverse events were usually mild to moderate and transient. The tolerability profile of lovastatin ER was similar to that of lovastatin IR. There were no reports of clinically relevant elevations in liver transaminases or creatine phosphokinase attributed to the drug in recipients of lovastatin ER.

CONCLUSION

The ER formulation of lovastatin provides smooth and sustained delivery of this established and well-tolerated agent over the dosage interval, significantly reducing LDL-cholesterol in patients with primary hypercholesterolaemia. If, as expected, the beneficial changes in lipid levels are maintained during long-term treatment and further clinical experience confirms the greater efficacy of the lovastatin ER formulation than the IR formulation, then lovastatin ER is likely to supplant lovastatin IR and provide a useful option in the management of patients with dyslipidaemia and prevention of coronary heart disease.

Valsartan therapy has additive anti-oxidative effect to that of fluvastatin therapy against low-density lipoprotein oxidation: studies in hypercholesterolemic and hypertensive patients

In hypercholesterolemic and hypertensive patients, an increased propensity of their low-density lipoprotein (LDL) to oxidative modification has been observed. Because oxidized LDL (ox-LDL) plays a major role in atherosclerosis, the current study analyzed the anti-oxidative effect of valsartan (an angiotensin II receptor antagonist) therapy in combination with fluvastatin therapy in these patients. Administration of 40 mg/d of fluvastatin for 2 months to seven patients resulted in significant reduction in plasma total and LDL cholesterol (by 24-28%). Valsartan administration (80 mg/d for an additional 2-month period) in combination with fluvastatin did not further affect plasma cholesterol levels. Fluvastatin therapy inhibited the susceptibility of LDL to copper ion-induced oxidation, as shown by prolongation of the lag time by 22% and by a reduction of thiobarbituric acid-reactive substances (TBARS) levels by 14%, as compared with the patient's LDL baseline oxidation. The addition of valsartan to fluvastatin resulted in a further 17% prolongation of the lag time and in an additional reduction of 21% in TBARS levels. In a parallel study, the LDL from eight patients who were first treated with 80 mg/d of valsartan for 2 months demonstrated reduced susceptibility to copper ion-induced oxidation, as observed by prolongation of lag time by 23% and reduction in TBARS levels by 19%, compared with the baseline values. The administration of 40 mg/d of fluvastatin for an additional 2 months in combination with valsartan, however, demonstrated no further inhibitory effect on LDL oxidation. The anti-oxidative properties of fluvastatin and valsartan against LDL oxidation were also demonstrated in vitro and the combination of both drugs was shown to have an additive effect. Valsartan therapy in hypercholesterolemic and hypertensive patients has an additive anti-oxidative effect to that of fluvastatin therapy. This may be related both to the anti-oxidative properties of valsartan and to the blocking of angiotensin II-induced oxidative stress.

Dyslipidemia and the vulnerable plaque

In the last decade, an increasingly sophisticated understanding of the pathogenesis of atherosclerosis and its cardiovascular consequences has emerged. The characteristics of the unstable atherosclerotic plaque, the substrate for the majority of acute coronary events, have been well defined: mild-to-moderate stenosis, a lipid-rich pool, few smooth muscle cells, a friable fibrous cap, and macrophage infiltration. Lipid modification, an important cardiovascular risk reduction strategy, induces a number of effects at the vascular level that may contribute to the clinical benefits seen in large-scale, prospective prevention trials. New developments in imaging technologies may afford improved opportunities to visualize the at-risk plaque and may provide new insights into the optimal management of the unstable plaque.

Influence of HMG-CoA reductase inhibitors on markers of coagulation, systemic inflammation and soluble cell adhesion

BACKGROUND

Beneath its lipid-lowering properties additional non-lipid effects of statin therapy are discussed. We therefore examined the impact of statins on laboratory markers of coagulation, inflammation and soluble cell adhesion to further explore these effects in 950 hospitalised patients with angiographically proven CAD.

METHODS AND RESULTS

Although no significant differences were found in total cholesterol, LDL and HDL and triglyceride levels a statistically lower value in 277 statin-treated patients was found for von Willebrand factor [162(130/224) vs. 208(154/283)%, P=0.0001], leukocyte count [6.9(5.8/8.4) vs. 7.3(6.1/9.4)/nl, P=0.0005], high sensitive CRP [4.3(1.8/10.8) vs. 7.6(2.8/20.0) mg/dl, P=0.0001], interleukin-6 [9.5(5.1/18.7) vs. 14.4(7.2/28.1) mg/dl, P=0.0001] and soluble p-selectin [112.6(82.0/146.0) vs. 127.8(93.8/162.4) mg/dl, P=0.001] compared to 673 patients without statin therapy. This result was confirmed in a subgroup of 510 patients matched for age, gender and percentage of acute coronary syndromes.

CONCLUSIONS

In statin treated patients significantly lower levels of coagulation, systemic inflammation and soluble cell adhesion markers were found. Therefore the effect of statin therapy may also be mediated by additional non-lipid-lowering effects.

Fluvastatin depresses the enhanced lipid peroxidation in vitamin E-deficient hamsters

Fluvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, has recently been reported to have the antioxidative activity in vitro. However, it is still unclear whether chronic treatment with this drug actually leads to amelioration of the redox status in the body. In this study, we investigated the antioxidative effect of fluvastatin in vivo, using a vitamin E-deficient hamster model, an in vivo model of enhanced oxidative stress. After pre-treatment with a vitamin E-deficient diet for 2 months, fluvastatin, pravastatin or probucol was added to the diet for 1 month. Vitamin E deficiency caused a significant increase in the levels of plasma oxidative stress markers such as 8-iso-prostaglandin F2alpha (8-iso-PGF2alpha) and hydroperoxides. Furthermore, there was a significant increase in the oxidizability of plasma lipids in the vitamin E-deficient animals, indicating that the oxidative stress was increased in the circulation. Fluvastatin markedly depressed the above oxidative stress markers in plasma, and significantly decreased the oxidizability of plasma lipids without affecting their levels. Probucol, a reference antioxidant, also showed a similar effect while pravastatin, another HMG-CoA reductase inhibitor, showed only a weak improvement. We suggest that the treatment with fluvastatin leads to a reduction of oxidative stress in vivo, which is mainly derived from its antioxidative property rather than its lipid-lowering activity.

Statins: mechanism of action and effects

The beneficial effects of statins are the result of their capacity to reduce cholesterol biosyntesis, mainly in the liver, where they are selectively distributed, as well as to the modulation of lipid metabolism, derived from their effect of inhibition upon HMG-CoA reductase. Statins have antiatherosclerotic effects, that positively correlate with the percent decrease in LDL cholesterol. In addition, they can exert antiatherosclerotic effects independently of their hypolipidemic action. Because the mevalonate metabolism generates a series of isoprenoids vital for different cellular functions, from cholesterol synthesis to the control of cell growth and differentiation, HMG-CoA reductase inhibition has beneficial pleiotropic effects. Consequently, statins reduce significantly the incidence of coronary events, both in primary and secondary prevention, being the most efficient hypolipidemic compounds that have reduced the rate of mortality in coronary patients. Independent of their hypolipidemic properties, statins interfere with events involved in bone formation and impede tumor cell growth.

Fluorescence spectroscopic analysis of circulating platelet activation during coronary angioplasty

BACKGROUND AND OBJECTIVE

Platelet activation during percutaneous transluminal coronary angioplasty (PTCA) initiates thrombus formation and plaque regrowth at sites of arterial injury, limiting procedure efficacy. We have developed a simple assay for circulating platelet activation based on fluorescence analysis of membrane fluidity and intracellular calcium concentration and light scattering analysis of platelet aggregation.

STUDY DESIGN/MATERIALS AND METHODS

Platelet activation state was measured in 45 patients undergoing angioplasty, before and after treatment with platelet inhibitors.

RESULTS

PTCA alone produced a decrease in pyrene dimer formation (P0.0083) and an increase in light scattering at 650 nm (P0.0128). Treatment with ADP and GPIIb/IIIa receptor antagonists reduced PTCA induced changes in pyrene dimer formation. An unexpected decrease in pyrene dimer formation (P0.05) was detected when the GPIIb/IIIa receptor antagonist was given together with an ADP receptor antagonist.

CONCLUSIONS

1) Analysis of membrane fluidity provides a sensitive marker for platelet activation state. 2) Reduced membrane fluidity after combined platelet inhibitor treatments suggests reduced antiplatelet efficacy.

Effects of long-term treatment with simvastatin on some hemostatic parameters in continuous ambulatory peritoneal dialysis patients

BACKGROUND/AIM

Disturbances in serum lipids, hemostasis and platelet functions are frequent features in uremia and may contribute to the progression of atherosclerosis and its thrombotic complications. Recently, attention has been paid to beneficial effects of statins on serum lipids and hemostasis in uremic patients. Peritoneally dialyzed (continuous ambulatory peritoneal dialysis; CAPD) subjects are particularly prone to dyslipidemia and have a high risk of cardiovascular death. The purpose of this work was to assess platelet functions, some hemostatic parameters and serum lipids in 8 hyperlipidemic CAPD patients treated with simvastatin (Zocor, MSD) for 6 months.

METHODS

Platelet aggregation in whole blood and in platelet-rich plasma (PRP) induced by collagen (2 microg/ml for whole blood and PRP), arachidonic acid (0.75 mM for whole blood and PRP), ADP (10 microM for whole blood and 5 microM for PRP) and ristocetin (0.75 mg/ml for whole blood and 1.5 mg/ml for PRP) was studied before and after 1, 3 and 6 months of simvastatin (dose: 10 mg at bedtime) treatment.

RESULTS

Whole-blood platelet aggregation induced by collagen decreased significantly after 3 and 6 months of the therapy, whereas in PRP, platelet aggregation induced by collagen and ADP decreased significantly after 6 months. Ristocetin-induced platelet aggregation in PRP decreased significantly after 3 and 6 months of simvastatin therapy. P-selectin remained unaltered by 6 months of simvastatin therapy. The fibrinolytic activity index was significantly higher after 3 months of the therapy when compared to the baseline values. Thrombomodulin, a marker of endothelial cell injury, was significantly lower after 3 and 6 months of the therapy. Prothrombin fragments 1 + 2 did not change significantly during 6 months of simvastatin administration. Cholesterol and LDL fell significantly as early as after 1 month and remained lowered during further months of the therapy.

CONCLUSION

Simvastatin is an effective hypolipemic agent and favorably affects platelet aggregation, endothelial function and fibrinolysis in CAPD patients.

The effects of converting from simvastatin to atorvastatin on plasminogen activator inhibitor type-1

Plasminogen activator inhibitor type-1 (PAI-1) is an important regulatory component of fibrinolysis and is elevated in the presence of endothelial dysfunction. Endothelial dysfunction and PAI-1 in patients with coronary artery disease (CAD) have been demonstrated to improve following simvastatin therapy. The effect of converting from simvastatin to atorvastatin on PAI-1 has not been reported and may be an additional consideration when making a formulary medication switch. Fourteen adult patients with hypercholesterolemia and CAD who were receiving simvastatin for a minimum of 3 months were randomized to continue on simvastatin or be converted to atorvastatin. Doses were adjusted to achieve or sustain a low-density lipoprotein (LDL) cholesterol of < or = 100 mg/dL. A fasting lipid panel and PAI-1 were obtained at baseline and following 10 weeks of treatment. Mean +/- SD LDL cholesterol at baseline (95.6 +/- 13.8 vs. 87.0 +/- 12.3 dL, p = 0.24) and following 10 weeks of simvastatin or atorvastatin (96.6 +/- 8.9 vs. 87.4 +/- 20.3 mg/dL, p = 0.29) were similar. No differences in PAI-1 were observed at baseline (47.7 +/- 19.3 vs. 64.6 +/- 22.2 ng/mL, p = 0.15) or at 10 weeks (51.1 +/- 32.5 vs. 63.9 +/- 26.9 ng/mL, p = 0.44). These data suggest that the conversion from simvastatin to atorvastatin does not adversely affect PAI-1 plasma concentrations in patients with CAD.

Use of statins in CNS disorders

It is well established that 3-hydroxy-3-methyglutaryl coenzyme A (HMG-CoA) reductase inhibitors ("statins") reduce cholesterol levels and prevent coronary heart disease (CHD). Although a causal relation between elevated cholesterol levels and stroke has not been well defined, a number of large secondary prevention studies and meta-analyses have shown that statin therapy reduces stroke in patients with CHD and hypercholesterolemia. In addition to the vascular effects of statins (stabilization of atherosclerotic plaques, decreased carotid intimal-medial thickness), there are increasing data to suggest that these agents have additional properties that are potentially neuroprotective. These include endothelial protection via actions on the nitric oxide synthase system, as well as antioxidant, anti-inflammatory and anti-platelet effects. These actions of statins might have potential uses in other neurological disorders such as Alzheimer's disease and certain types of brain tumors.