Differential effects of pravastatin, simvastatin, and atorvastatin on Ca2+ release and vascular reactivity

Simvastatin causes pulmonary artery relaxation by blocking smooth muscle ROCK and calcium channels: Evidence for an endothelium-independent mechanism

Simvastatin reduces pulmonary arterial pressure and right ventricular hypertrophy in animal models of pulmonary arterial hypertension (PAH) and is thought to restore endothelial dysfunction. In vivo effects of drugs are complicated by several factors and little is known of the direct effects of statins on pulmonary arteries. This study investigated the direct effects of simvastatin on pulmonary arteries isolated from rats with or without monocrotaline-induced PAH. Simvastatin suppressed contractions evoked by the thromboxane A2 receptor agonist U46619 (30 nM), the α₁–adrenergic agonist phenylephrine (5 μM) and KCl (50 mM) by ~50% in healthy and diseased arteries, but did not reduce contraction evoked by sarco/endoplasmic reticulum ATPase blockers. It relaxed hypertensive arteries in the absence of stimulation. Removing the endothelium or inhibiting eNOS did not prevent the inhibition by simvastatin. Inhibiting RhoA/rho kinase (ROCK) with Y27632 (10 μM) suppressed contractions to U46619 and phenylephrine by ~80% and prevented their inhibition by simvastatin. Y27632 reduced KCl-induced contraction by ~30%, but did not prevent simvastatin inhibition. Simvastatin suppressed Ca²⁺ entry into smooth muscle cells, as detected by Mn²⁺ quench of fura-2 fluorescence. The calcium antagonist, nifedipine (1 μM), almost abolished K⁺-induced contraction with less effect against U46619 and phenylephrine. We conclude that simvastatin relaxes pulmonary arteries by acting on smooth muscle to interfere with signalling through G-protein coupled receptors and voltage-dependent Ca²⁺ entry. Its actions likely include inhibition of ROCK-dependent Ca²⁺ sensitisation and voltage-gated Ca²⁺ channels. These are likely to contribute to the beneficial effects of simvastatin in animal models of PAH.

Relaxant effect of atorvastatin on isolated rat gastric fundus strips: implications for Ca2+-signalling mechanisms

Statins are determined to have various pleiotropic effects apart from their lipid-lowering properties. Herein, we investigated the direct effects of atorvastatin on gastric smooth muscle tone. Atorvastatin effectively relaxed isolated rat gastric fundus strips precontracted with acetylcholine, potassium chloride, and serotonin. Incubation of the strips with nitric oxide synthase inhibitor, l-NOARG (10−4 M, 20 min), l-type voltage-operated Ca2+ channel (VOCC) blocker, nifedipine (10−6 M, 30 min), KATP channel blocker, glibenclamide (10−5 M, 30 min), or precursor of cholesterol, mevalonate (10−2 M, 45 min) did not change the relaxations to atorvastatin. However, pretreatment of fundus strips with atorvastatin (3×10−5–3×10−4 M, 30 min) inhibited the contractions to calcium chloride (10−4–10−1 M), acetylcholine (10–4 M), and caffeine (20 mM) in the calcium-free medium. Moreover, atorvastatin reduced the contractions induced by sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) inhibitor, cyclopiazonic acid (10−7–3×10−5 M). The current study demonstrated that atorvastatin produces an acute relaxant effect on gastric fundus strips, which appears to be mediated by several Ca2+-signalling mechanisms such as the blockade of l-type VOCC-independent Ca2+ entry, decrease in smooth muscle Ca2+ sensitivity, inhibition of IP3- and ryanodine-sensitive intracellular stores to mediate Ca2+ release, as well as the activation of SERCA. This acute relaxing effect seems unlikely to be related with nitric oxide, KATP channels, and the mevalonate pathway.

Cilostazol enhances atorvastatin-induced vasodilation of female rat aorta during aging

Statins have cholesterol-independent effects including an increased vascular nitric oxide activity and are commonly used by patients with cardiovascular disease. Such patients frequently have cardiovascular diseases, which may be treated with cilostazol, a platelet aggregation inhibitor. This study was designed to investigate whether combined use of cilostazol would increase the inhibitory effect of statin on vascular smooth muscle and how maturation would affect these responses. Female Wistar rats, aged 3–4 months (young) and 14–15 months (adult), were sacrificed by cervical dislocation and the thoracic aorta was dissected and cut into 3- to 4-mm-long rings. The rings were mounted under a resting tension of 1 g in a 20-ml organ bath filled with Krebs–Henseleit solution. Rings were precontracted with phenylephrine (10−6 M), and the presence of endothelium was confirmed with acetylcholine (10−6 M). Then, the concentration–response curves were obtained for atorvastatin alone (10−10 to 3 × 10−4 M; control) and in the presence of cilostazol (10−6 M) in young and adult rat aortas. This experimental protocol was also carried out in aorta rings, which had been pretreated with NG-nitro-l-arginine methyl ester (l-NAME, 10−4 M). Atorvastatin induced concentration-dependent relaxations in young and adult rat thoracic aorta rings precontracted with phenylephrine. The pIC50 value of atorvastatin was significantly decreased in adult rat aortas. In addition, pretreatment of aortas with cilostazol enhanced the potency of atorvastatin in both young and adult aortas. Incubation with l-NAME did not completely eliminate the relaxations to atorvastatin in the presence of cilostazol. These results suggest that combined application of cilostazol with atorvastatin was significantly more potent than atorvastatin alone. Combined drug therapy may be efficacious in delaying the occurrence of cardiovascular events.

Serum cholesterol levels and postoperative atrial fibrillation

Background

Post-operative atrial fibrillation is an important complication after coronary bypass surgery. As inflammation and oxidative stress were makedly encountered in the etiology, high cholesterol was also defined to provoke atrial fibrillation. In this present study, the relationship between postoperative atrial fibrillation and preoperative serum lipid levels were evaluated.

Methods

A total of 100 patients, who were operated at the department of Cardiovascular Surgery of our hospital were included to the study analysis. Patients, who had preoperative atrial fibrillation, thyroid dysfunction, or left atrial dilatation (above 4.5 cm) were excluded from the study. Patients were divided into two groups with postoperative atrial fibrillation development (Group I n = 36), and without atrial fibrillation development (Group II n = 64). Preoperative routine blood analyses, ECG, echocardiography were evaluated. Patients were followed for atrial fibrillation development for one month starting from the intensive care unit at the postoperative period. Serum lipid profiles and thyroid function were measured. For homogenization of inflammatory factors and oxidative stress, treatments other than statins, betablockers, calcium channel blockers, aspirin, ACE inhibitors, and ARB were stopped for 10 days. Atrial fibrillation for at least ≥5 minutes in the intensive care unit was accepted as postoperative atrial fibrillation.

Results

Demographic data were similiar between groups (p > 0.05). There was no difference in TC levels between groups, whereas LDL-C levels were statistically lower in patients developing post-operative atrial fibrillation (106.67 ± 28.36 vs 118.75 ± 27.75; P < 0.05).

Conclusion

The more lowered is the LDL-C in the preoperative period, the more reduced risk of postoperative atrial fibrillation development. High levels of LDL-C in the preoperative period could be predictor of atrial fibrillation development in the post operative period.

Dysfunction of vascular smooth muscle and vascular remodeling by simvastatin

Statins, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, are widely prescribed for hypercholesterolemia. With the increasing use of statins, numerous reports demonstrated that statins can cause damage to skeletal muscles. However, the toxicities of statins on vascular smooth muscle, which are essential to cardiovascular homeostasis, have not been previously described. Here, we examined the effects of simvastatin on the contractile function and the integrity of vascular smooth muscle in isolated rat thoracic aortic rings, primary cultured vascular smooth muscle cells (VSMCs) in vitro and rats in vivo. In aortic rings, simvastatin suppressed the normal agonist-induced contractile responses in time- and concentration-dependent manners (0.86 g ± 0.11 at 10 μM simvastatin for 24 h compared with 1.89 g ± 0.11 at control). The suppression persisted in the endothelium-denuded aortic rings and was irreversible even after wash-out of simvastatin. Simvastatin suppressed the contraction induced by Bay K8644, an activator of voltage-operated Ca²⁺ channel (VOCC) in rat aortic rings and abolished agonist-induced intracellular Ca²⁺ increase in VSMCs. The simvastatin-induced contractile dysfunction was reversed by the supplementation of mevalonate and geranylgeranylpyrophosphate, precursors for protein isoprenylation. Consistently, activation of RhoA, a representative isoprenylated protein, was disrupted by simvastatin in VSMCs and RhoA-mediated phosphorylation of MYPT1 and CPI-17, and tonic tension were also suppressed. Notably, prolonged treatment of simvastatin up to 48 h induced apoptosis of vascular smooth muscle in aortic rings. Most importantly, simvastatin treatment in vivo significantly attenuated the agonist-induced vasoconstriction in rats ex vivo and induced a decrease in luminal area of the vascular wall. Collectively, these results demonstrate that simvastatin can impair the normal vascular contractility by disturbing Ca²⁺ influx and RhoA activity, ultimately leading to apoptosis and structural remodeling.

Acute simvastatin inhibits K ATP channels of porcine coronary artery myocytes

Background

Statins (3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase inhibitors) consumption provides beneficial effects on cardiovascular systems. However, effects of statins on vascular K_ATP channel gatings are unknown.

Methods

Pig left anterior descending coronary artery and human left internal mammary artery were isolated and endothelium-denuded for tension measurements and Western immunoblots. Enzymatically-dissociated/cultured arterial myocytes were used for patch-clamp electrophysiological studies and for [Ca²⁺]_i, [ATP]_i and [glucose]_o uptake measurements.

Results

The cromakalim (10 nM to 10 µM)- and pinacidil (10 nM to 10 µM)-induced concentration-dependent relaxation of porcine coronary artery was inhibited by simvastatin (3 and 10 µM). Simvastatin (1, 3 and 10 µM) suppressed (in okadaic acid (10 nM)-sensitive manner) cromakalim (10 µM)- and pinacidil (10 µM)-mediated opening of whole-cell K_ATP channels of arterial myocytes. Simvastatin (10 µM) and AICAR (1 mM) elicited a time-dependent, compound C (1 µM)-sensitive [³H]-2-deoxy-glucose uptake and an increase in [ATP]_i levels. A time (2–30 min)- and concentration (0.1–10 µM)-dependent increase by simvastatin of p-AMPKα-Thr¹⁷² and p-PP2A-Tyr³⁰⁷ expression was observed. The enhanced p-AMPKα-Thr¹⁷² expression was inhibited by compound C, ryanodine (100 µM) and KN93 (10 µM). Simvastatin-induced p-PP2A-Tyr³⁰⁷ expression was suppressed by okadaic acid, compound C, ryanodine, KN93, phloridzin (1 mM), ouabain (10 µM), and in [glucose]_o-free or [Na⁺]_o-free conditions.

Conclusions

Simvastatin causes ryanodine-sensitive Ca²⁺ release which is important for AMPKα-Thr¹⁷² phosphorylation via Ca²⁺/CaMK II. AMPKα-Thr¹⁷² phosphorylation causes [glucose]_o uptake (and an [ATP]_i increase), closure of K_ATP channels, and phosphorylation of AMPKα-Thr¹⁷² and PP2A-Tyr³⁰⁷ resulted. Phosphorylation of PP2A-Tyr³⁰⁷ occurs at a site downstream of AMPKα-Thr¹⁷² phosphorylation.

Long-term administration of rosuvastatin prevents contractile and electrical remodelling of diabetic rat heart

In recent years, many findings have been presented about the potential benefit of statin therapy on diabetes-induced cardiovascular complications. Cardioprotective effects of statins were suggested to be mediated at least in part through inhibition of small GTPases, particularly those of the Rho family. The present study was designed to examine whether rosuvastatin can improve electrical remodeling and contractile dysfunction in type 1 diabetic rat heart via modulation of RhoA pathway. Type 1 diabetes was induced by single dose injection of STZ (50 mg/kg). One week after injection rosuvastatin (10 mg/kg/day) and sham treatment was given for 5 weeks in the diabetic rats, as well as in control groups. Shortening and Ca²⁺ transients were recorded in myocytes loaded with Fura2-AM. Membrane currents and Ca²⁺ transients were measured synchronously via whole-cell patch clamping. In untreated diabetic rats, relaxation of shortening and decay of the matched Ca²⁺ transients were prolonged. Fractional shortening and Ca²⁺ transients were also decreased. Rosuvastatin treatment reversed those changes. I(CaL) density did not change in either group but rosuvastatin recovered the loss of sarcoplasmic reticulum Ca²⁺ and Na⁺/Ca²⁺ exchange as evidenced from amplitude and decay of caffeine-induced Ca²⁺ transients, peak INCX and calculated sarcoplasmic reticulum Ca²⁺ content. Diabetes-induced attenuation of I(to) and I(sus) was also reversed, whilst I(K1) was unchanged in diabetes and unaffected by treatment. Rosuvastatin prevented the diabetes-induced increase in RhoA expression. Plasma cholesterol and triglyceride levels were higher in diabetic rats, but rosuvastatin reduced only the latter. In conclusion, HMG-CoA reductase inhibitor rosuvastatin can prevent diabetes-induced electrical and functional remodeling of heart due to inhibition of RhoA signalling rather than reduction of cholesterol level.

Antibacterial activity of statins: a comparative study of atorvastatin, simvastatin, and rosuvastatin

Background

Statins have several effects beyond their well-known antihyperlipidemic activity, which include immunomodulatory, antioxidative and anticoagulant effects. In this study, we have tested the possible antimicrobial activity of statins against a range of standard bacterial strains and bacterial clinical isolates.

Methods

Minimum inhibitory concentrations (MIC) values were evaluated and compared among three members of the statins drug (atorvastatin, simvastatin, and rosuvastatin).

Results

It was revealed that statins are able to induce variable degrees of antibacterial activity with atorvastatin, and simvastatin being the more potent than rosuvastatin. Methicillin-sensitive staphylococcus aureus (MSSA), methicillin-resistant staphylococcus aureus (MRSA), vancomycin-susceptible enterococci (VSE), vancomycin-resistant enterococcus (VRE), acinetobacter baumannii, staphylococcus epidermidis, and enterobacter aerogenes, were more sensitive to both atorvastatin, and simvastatin compared to rosuvastatin. On the other hand, escherichia coli, proteus mirabilis, and enterobacter cloacae were more sensitive to atorvastatin compared to both simvastatin and rosuvastatin. Furthermore, most clinical isolates were less sensitive to statins compared to their corresponding standard strains.

Conclusion

Our findings might raise the possibility of a potentially important antibacterial class effect for statins especially, atorvastatin and simvastatin.

Anti-inflammatory effect of atorvastatin on vascular reactivity and insulin resistance in fructose fed rats

We investigated the possible protective effect of atorvastatin against vascular dysfunction associated with insulin resistance (IR) in fructose-fed model rats. The effect of atorvastatin (10 mg/kg/day for 8 weeks) on vascular reactivity, glucose, cholesterol, insulin, and the IR index in a well-established model of dietary hypertriglyceridemia, the fructose-fed rat, was investigated. Fructose feeding (10% fructose in drinking water for 8 weeks) induced hypercholesterolemia and hyperinsulinemia without any change in blood glucose levels. Fructose feeding also elevated serum tumor necrosis factor-alpha (TNF-α), the insulin resistance index, leukocyte infiltration, and endothelial cell pyknosis. Fructose feeding induced hyper-responsiveness to both phenylephrine (PE), KCl, and hyporesponsiveness to acetylcholine (Ach) but not to sodium nitroprusside-induced relaxation. Atorvastatin, given concurrently with fructose, reduced hypercholesterolemia, hyperinsulinemia, TNF-α level, and the IR index. It also reduced leukocyte infiltration and endothelial cell pyknosis and decreased hyper-responsiveness to both PE and KCl but did not affect hyporesponsiveness to Ach relaxation. In conclusion, atorvastatin protected against impairment in aortic vascular reactivity associated with insulin resistance, particularly increased contractility, but not reduced endothelium-dependent relaxation, by a mechanism involving a reduction in cholesterol and IR in addition to anti-inflammatory effects.

Differential metabolic effects of distinct statins

Reciprocal relationships between endothelial dysfunction and insulin resistance suggest that therapies improving endothelial dysfunction will simultaneously improve insulin sensitivity and other metabolic parameters. However, previous studies with some statins either did not alter insulin sensitivity or promoted insulin resistance despite significant improvements in endothelial dysfunction and decreases in circulating pro-inflammatory markers. This may be due to pleiotropic or off-target effects of some statins to cause insulin resistance by diverse mechanisms unrelated to endothelial dysfunction. Indeed, there is evidence of other differential metabolic actions of distinct statins including effects on hydroxymethylglutaryl-CoA reductase inhibition, isoprotenoid synthesis, calcium release, glucose transport, insulin secretion, and/or insulin resistance. Pravastatin increases expression of adiponectin mRNA, enhances adiponectin secretion, increases plasma levels of adiponectin, and enhances insulin sensitivity in mice and humans. Clinical studies including large scale randomized controlled trials demonstrate potential differences between individual statins, with pravastatin promoting risk reduction for new onset of diabetes. Conversely, other statins including atorvastatin, rosuvastatin, and simvastatin all promote significant increase in this risk. Given the frequent concordance of metabolic diseases including diabetes, obesity, and metabolic syndrome with cardiovascular diseases associated with hyperlipidemia, it is important to understand the potential metabolic risks and benefits of therapies with distinct statins. In this review, we discuss these differential effects of statins on metabolic homeostasis and insulin sensitivity.

Interactions between cell death induced by statins and 7-ketocholesterol in rabbit aorta smooth muscle cells

BACKGROUND AND PURPOSE

7-Ketocholesterol, an oxysterol present in atherosclerotic lesions, induces smooth muscle cell (SMC) death, thereby destabilizing plaques. Statins protect patients from myocardial infarction, though they induce SMC apoptosis. We investigated whether statins and 7-ketocholesterol exerted additive cell death effects.

EXPERIMENTAL APPROACH

Cultured rabbit aorta SMCs (passage 2-6) were exposed to 7-ketocholesterol with or without fluvastatin, simvastatin or pravastatin. Uptake of neutral red (NR), monolayer protein, cleavage of the pan-caspase substrate Asp-Glu-Val-Asp-rhodamine110, cell morphology (light and electron microscopy) and processing of microtubule-associated protein 1 light chain 3 (LC3, immunoblot) were determined.

KEY RESULTS

NR uptake declined upon 18 h exposure to 25 microM 7-ketocholesterol (-41+/-3%, n=13), 100 microM fluvastatin (-59%) or 30-100 microM simvastatin (-28 to -74%). Oxysterol and high statin concentrations exerted additive effects, but lower concentrations (fluvastatin 10-30 microM, simvastatin 1-10 microM) partly reversed viability loss. 7-Ketocholesterol caused intense cytoplasmic vacuolization, processing of LC3-I to LC3-II, but little caspase activation (increase 29.5%). Fluvastatin (10-100 microM, 70-545% increase) and simvastatin (3-100 microM 43-322% increase) induced caspase activation without LC3 processing, but failed to activate caspases in 7-ketocholesterol-treated SMCs. Pravastatin up to 100 microM was always inactive.

CONCLUSIONS AND IMPLICATIONS

7-Ketocholesterol caused SMC death, mainly via autophagic vesicle formation with LC3 processing, whereas lipophilic statins evoked SMC apoptosis. Cell death following 7-ketocholesterol and low statin concentrations were not additive, presumably because the autophagic process interfered with statin-induced caspase activation. This further illustrates that drug effects in normal SMCs are not necessarily predictive for activities in atherosclerotic settings.

Modulation by simvastatin of iberiotoxin-sensitive, Ca2+-activated K+ channels of porcine coronary artery smooth muscle cells

BACKGROUND AND PURPOSE

Statins (3-hydroxy-3-methyl-glutaryl coenzyme A (HMG CoA) reductase inhibitors) have been demonstrated to reduce cardiovascular mortality. It is unclear how the expression level of HMG CoA reductase in cardiovascular tissues compares with that in cells derived from the liver. We hypothesized that this enzyme exists in different cardiovascular tissues, and simvastatin modulates the vascular iberiotoxin-sensitive Ca2+-activated K(+) (BK(Ca)) channels.

EXPERIMENTAL APPROACHES

Expression of HMG CoA reductase in different cardiovascular preparations was measured. Effects of simvastatin on BK(Ca) channel gatings of porcine coronary artery smooth muscle cells were evaluated.

KEY RESULTS

Western immunoblots revealed the biochemical existence of HMG CoA reductase in human cardiovascular tissues and porcine coronary artery. In porcine coronary artery smooth muscle cells, extracellular simvastatin (1, 3 and 10 microM) (hydrophobic), but not simvastatin Na+ (hydrophilic), inhibited the BK(Ca) channels with a minimal recovery upon washout. Isopimaric acid (10 microM)-mediated enhancement of the BK(Ca) amplitude was reversed by external simvastatin. Simvastatin Na+ (10 microM, applied internally), markedly attenuated isopimaric acid (10 microM)-induced enhancement of the BK(Ca) amplitude. Reduced glutathione (5 mM; in the pipette solution) abolished simvastatin -elicited inhibition. Mevalonolactone (500 microM) and geranylgeranyl pyrophosphate (20 microM) only prevented simvastatin (1 and 3 microM)-induced responses. simvastatin (10 microM ) caused a rottlerin (1 microM)-sensitive (cycloheximide (10 microM)-insensitive) increase of PKC-delta protein expression.

CONCLUSIONS AND IMPLICATIONS

Our results demonstrated the biochemical presence of HMG CoA reductase in different cardiovascular tissues, and that simvastatin inhibited the BK(Ca) channels of the arterial smooth muscle cells through multiple intracellular pathways.

Lipid-lowering therapy with statins, a new approach to antiarrhythmic therapy

Inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (statins) are the most effective and best-tolerated drugs to treat elevated levels of low-density lipoprotein cholesterol (LDL-C). In addition, they exhibit other effects unrelated to their lipid lowering effects (pleiotropic actions). In recent years, experimental and clinical evidence demonstrates that statins exert antiarrhythmic properties, reducing the recurrences of supraventricular and life-threatening ventricular arrhythmias both in patients with and without coronary artery disease (CAD). Thus, statins may constitute a novel therapeutic approach to cardiac arrhythmias. This article reviews the antiarrhythmic properties of statins as well as the possible mechanisms involved, including the lowering of LDL-C levels, the improvement of endothelial dysfunction and autonomic function, the stabilization of the atherosclerotic plaques, the antioxidant, antiinflammatory, antithrombotic and cardioprotective properties and the modulation of transmembrane ion fluxes.

Effects of simvastatin on cardiohemodynamic responses to ischemia–reperfusion in isolated rat hearts

Simvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, has long been thought to exert its benefits by reducing cholesterol synthesis, and has been shown to significantly reduce cardiovascular events and mortality in patients with or without coronary artery disease. However, it is still unknown whether acute administration of simvastatin beneficially affects the cardiac function prior or during ischemia-reperfusion. The aim of this study is to evaluate the cardioprotective effect of acute simvastatin treatment on isolated rat hearts or isolated ischemia-reperfusion hearts. Hearts were isolated from male Sprague-Dawley rats and attached to a Langendorff apparatus. The isolated hearts with or without ischemia (15 min) and reperfusion (60 min) were perfused with different concentrations of simvastatin. The parameters of cardiac function (such as left ventricular developed pressure [LVDP], +dp/dt max, and -dp/dt max), heart rate, and coronary flow were recorded. Simvastatin (3-30 micromol/l) significantly increased LVDP, +dp/dt max, and -dp/dt max in isolated rat hearts perfused for 60 min. Heart rate was depressed by 30 micromol/l simvastatin and the coronary flow was increased by 10 and 30 micromol/l simvastatin. At a concentration of 100 micromol/l simvastatin, worsening of heart function and subsequent cardiac arrest occurred. Administration of simvastatin (3-30 micromol/l) significantly preserved cardiac function detected by LVDP, +dp/dt max, and -dp/dt max in the isolated ischemia/reperfused (15/60 min) rat hearts. Simvastatin also significantly decreased heart rate at 30 micromol/l, and increased coronary flow at 10 and 30 micromol/l in these rat hearts. However, the protective effect of simvastatin reverted to increased damage at 100 micromol/l. Only 3 micromol/l simvastatin pretreatment before 15/60 min ischemia-reperfusion altered LVDP, +dp/dt max, and -dp/dt max. Both heart rate and coronary flow were unaltered after simvastatin pretreatment. Since simvastatin at a concentration lower than 100 micromol/l exerted beneficial effects on cardiac function in isolated perfused rat hearts, it could be applied just after myocardial ischemia and reperfusion.

Statins Decrease Serotonin-Induced Contractions in Coronary Arteries of Swine in vitro

Recent evidence suggests that statins improve the status of patients with coronary artery disease not only by reducing cholesterol levels, but also by acting at the level of the endothelium-smooth muscle unit. Previous results from our laboratory showed that these drugs interact with the vascular wall by partially inhibiting calcium-dependent, agonist-induced contractions in rat aortas. To evaluate whether this effect is also extended to the coronary vasculature, we assessed the effect of statins on serotonin (5-HT) induced contractions of left and right coronary arteries of swine. Concentration-response curves for the 5-HT-induced contractions (from 0.1 nmol/l to 100 micromol/l) were calculated on rings from both coronaries in the presence and absence of either (5 micromol/l) pravastatin, mevastatin, simvastatin, lovastatin, or atorvastatin. After a 45-min incubation period, all statins significantly reduced the Emax for the 5-HT-induced contractions, ranging from 51.9 +/- 1.9% (simvastatin) to 15.9 +/- 2.0% (pravastatin) in the left coronary artery and from 48.8 +/- 2.0% (simvastatin) to 17.8 +/- 2.5% (pravastatin) in the right coronary artery. The EC50 values for the 5-HT-induced contractions were 0.150 +/- 0.005 micromol/l for the left coronary artery and 0.171 +/- 0.010 micromol/l for the right coronary artery. These values significantly changed after incubation with statins, ranging from 1.240 +/- 0.101 micromol/l (for simvastatin) to 0.081+/- 0.008 micromol/l (for pravastatin) in the left coronary artery and from 1.410 +/- 0.075 micromol/l (for simvastatin) to 0.084 +/- 0.008 micromol/l (for pravastatin) in the right coronary artery. This evidence supports the possibility that, beyond their lipid-lowering properties, statins may provide a beneficial effect in atherosclerotic patients by reducing the tone in the coronary vasculature, facilitating blood flow to the myocardium.

Pravastatin Decreases Blood Pressure in Hypertensive and Hypercholesterolemic Patients Receiving Antihypertensive Treatment

BACKGROUND

Previous studies have suggested that the lipid-lowering agents, statins, may help reduce blood pressure (BP). The goal of the present study was to characterize the effect of pravastatin on BP in hypercholesterolemic and hypertensive patients already receiving antihypertensive drugs.

METHODS AND RESULTS

Eighty-two patients with hypercholesterolemia were retrospectively studied before and after 3 months of treatment with pravastatin. Forty-four patients had hypertension (HT group) and were receiving antihypertensive treatment, while the remaining 38 patients were normotensive (NT group). Patients in the HT group were further subdivided into those with uncontrolled or controlled BP. Pravastatin treatment significantly reduced systolic BP (SBP) in the HT group (134+/-16 to 130+/-13 mmHg, p<0.005) but not in the NT group (124+/-10 to 123+/-9 mmHg, p=0.52), despite the fact that treatment significantly reduced low-density lipoprotein cholesterol in both groups (HT group 178+/-27 to 132+/-17 mg/dl, p<0.0001; NT group 169+/-27 to 125+/-21 mg/dl, p<0.0001). Further, pravastatin significantly decreased SBP in the uncontrolled BP group (148+/-7 to 138+/-12 mmHg, p<0.005) but not in the controlled BP group (122+/-10 to 123+/-9 mmHg, p=0.72).

CONCLUSION

Concomitant use of statins and antihypertensive drugs could result in improved BP control in hypertensive patients with hypercholesterolemia.

The effects of HMG-CoA reductase inhibitors on endothelial function

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

Effects of statins on vascular function of endothelin-1

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

Statins and proteinuria

The proteinuria associated with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors is composed of primarily low-molecular weight proteins that disappear rapidly following discontinuation of the statin agent. More importantly, no evidence exists of nephrotoxicity or reduced renal function observed with the approved clinical dosages of any available statins. Recent clinical studies have suggested actual improvement in renal function demonstrated by decreases in creatinine concentrations and improvement in estimated glomerular filtration rates with both short-term and long-term administration of these agents. The progressive fibrosis and renal scarring of chronic kidney disease appears to be the end result of increased protein traffic in the proximal renal tubule. Early animal and recent clinical studies have suggested that treatment with statin agents in established chronic kidney disease can, in fact, provide renoprotection over and above that observed with aggressive blood pressure control and the use of angiotensin II antagonists.

Regulation of Vascular Tone from Spontaneously Hypertensive Rats by the HMG-CoA Reductase Inhibitor, Simvastatin

The acute effect of simvastatin on aortic rings from spontaneously hypertensive rats (SHRs) was identified. Simvastatin-evoked relaxations of both depolarized and phenylephrine-precontracted arteries were independent of the presence of endothelium. This effect was inhibited by diltiazem and mevalonate, but not by the Rho-kinase inhibitor, Y-27632. Simvastatin prevented contraction induced by phenylephrine, calcium ionophore A-23187 and CaCl2 in Ca2+-free medium. Y-27632 decreased the effect of simvastatin. On the contrary, contraction induced by noradrenaline in Ca2+-free medium was not affected. These results suggest that simvastatin elicited an effect on vascular smooth muscle cells from SHRs that may involve blockade of extracellular calcium entry and decrease vascular contraction by affecting Rho-kinase.

Effects of simvastatin on cardiac performance and expression of sarcoplasmic reticular calcium regulatory proteins in rat heart

AIM

To investigate the effect of simvastatin on the cardiac contractile function and the alteration of gene and protein expression of the sarcoplasmic calcium regulatory proteins, including sarcoplasmic reticulum Ca2+-ATPase (SERCA), phospholamban (PLB), and ryanodine receptor 2 (RyR2) in rat hearts.

METHODS

Langendorff-perfused rat hearts were subjected to 60-min perfusion with different concentrations of simvastatin (1, 3, 10, 30, or 100 microml/L), and the parameters of cardiac function such as left ventricular developed pressure (LVDP), +dp/dtmax, and -dp/dtmax were determined. The cultured neonatal rat ventricular cardiomyocytes were incubated with simvastatin (1, 3, 10, 30, and 100 micromol/L) for 1 h or 24 h. The levels of SERCA, PLB, and RyR2 expression were measured by reverse transcription-polymerase chain reaction and Western blot. Cytotoxic effect of simvastatin on ventricular cardiomyocytes was assessed by the MTT colorimetric assay.

RESULTS

LVDP, +dp/dtmax, and -dp/dtmax of hearts were increased significantly after treatment with simvastatin 3, 10, and 30 micromol/L. In simvastatin-treated isolated hearts, the levels of mRNA expression of SERCA and RyR2 were elevated compared with the control (P<0.05), while the mRNA expression of PLB did not change. After the cultured neonatal rat ventricular cardiomyocytes were incubated with 3, 10, 30, and 100 mumol/L simvastatin for 1 h, SERCA and RyR2 mRNA expressions of cardiomyocytes rose, but there was no alteration in protein expressions. However, with the elongation of simvastatin treatment to 24 h, the protein expression of SERCA and RyR2 were also elevated. Additionally, simvastatin (1-30 micromol/L) had no influence on cell viability of cultured cardiac myocytes, but simvastatin 100 micromol/L inhibited the cell viability.

CONCLUSION

Simvastatin improved cardiac performance accompanied by the elevation of SERCA and RyR2 gene and protein expression.

Relaxant effects of pravastatin, atorvastatin and cerivastatin on isolated rat aortic rings

Increasing evidence suggests that statins may have pleiotropic effects on vascular wall independent of their cholesterol lowering properties. In the present study, we investigated the acute vascular effects of pravastatin, atorvastatin and cerivastatin on rat isolated aortic rings. Statins effectively and comparably relaxed the aortic rings precontracted submaximally with noradrenaline, in a concentration-dependent manner, in which a high potency was observed with cerivastatin. Endothelium removal or incubation of the aortic rings with nitric oxide synthase inhibitor L-NOARG (10(-4) M) and/or cyclooxygenase inhibitor indomethacin (10(-5) M) significantly attenuated the acute vasorelaxation induced by either of statin. Additionally, different from the other two statins, a significant reduction was observed in response to cerivastatin in the presence of KATP channel inhibitor, glibenclamide (10(-5) M) and Na+- K+ ATPase inhibitor, ouabain (10(-4) M). Furthermore, pretreatment of the rings with the cholesterol precursor mevalonate (10(-3) M) significantly inhibited the endothelium-mediated relaxant effects of the statins. Our findings suggest that statins could acutely modulate vascular tone importantly by endothelium-dependent and mevalonate-related pathways.

Fluvastatin: clinical and safety profile

Therapy with HMG-CoA reductase inhibitors (statins) has been shown to significantly reduce major coronary events and death in a wide range of individuals at risk for these events. In addition, recent observations suggest that some of the clinical benefits associated with statin therapy may be pleiotropic; that is, independent of their cholesterol-inhibiting action. It is clear that the clinical benefits associated with statin therapy far outweigh the risks; however, there may be important clinical differences among agents within the class, related to both benefits and drug safety. Evaluation of the benefit-to-risk profile for each available statin should include considering the results of randomised clinical outcome trials, the safety record of each agent, effect on lipoproteins and evidence of beneficial pleiotropic properties.Recently, data from several clinical outcome trials have shown that substantial benefits are associated with treatment with fluvastatin in diverse populations. In particular, data from two large, randomised clinical trials have demonstrated that fluvastatin is effective for secondary prevention of cardiac events in patients following coronary intervention procedures, and for primary prevention of cardiac events in renal transplant recipients. Pleiotropic benefits for fluvastatin have been shown in experimental and clinical studies as well. Fluvastatin was the first statin available as an extended-release product (fluvastatin XL 80mg); both formulations have demonstrated efficacy and safety in a wide range of patients. Taken together, these clinical outcomes and safety data suggest a strong benefit-to-risk profile for fluvastatin.

Simvastatin Induces Death of Multiple Myeloma Cell Lines

Background

Accumulating reports indicate that statins widely prescribed for hypercholesteromia have antineoplastic activity. We hypothesized that because statins inhibit farnesylation of Ras that is often mutated in multiple myeloma (MM), as well as the production of interleukin (IL)-6, a key cytokine in MM, they may have antiproliferative and/or proapoptotic effects in this malignancy.

Methods

U266, RPMI 8226, and ARH77 were treated with simvastatin (0–30 μM) for 5 days. The following aspects were evaluated: viability (IC50), cell cycle, cell death, cytoplasmic calcium ion levels, supernatant IL-6 levels, and tyrosine kinase activity.

Results

Exposure of all cell lines to simvastatin resulted in reduced viability with IC50s of 4.5 μM for ARH77, 8 μM for RPMI 8226, and 13 μM for U266. The decreased viability is attributed to cell-cycle arrest (U266, G1; RPMI 8226, G2M) and cell death. ARH77 underwent apoptosis, whereas U266 and RPMI 8226 displayed a more necrotic form of death. Cytoplasmic calcium levels decreased significantly in all treated cell lines. IL-6 secretion from U266 cells was abrogated on treatment with simvastatin, whereas total tyrosine phosphorylation was unaffected. Conclusions: Simvastatin displays significant antimyeloma activity in vitro. Further research is warranted for elucidation of the modulated molecular pathways and clinical relevance.

The role of statins in vascular disease

BACKGROUND

Recent publications have highlighted the benefits of statins in non-cardiac occlusive disease but also the failure of vascular surgeons to recognise and treat the risk factors for atherosclerosis, in particular hypercholesterolaemia. The aim of this review is to clarify the current experimental and clinical evidence for the use of statins in vascular disease.

METHODS

Literature compiled from an extensive search of Medline and the Cochrane database has been used for the basis of this review.

RESULTS

Experimental and clinical evidence consistently reports that statins improve endothelial dysfunction, are anti-inflammatory, anti-proliferative, anti-thrombogenic and anti-proteolytic. These effects are known to inhibit atherogenesis and improve plaque stability. Independent groups support the use of statins in the prevention of both primary and secondary cardiac events. The National Stroke association recommends their use to reduce strokes following myocardial infarction and the Heart Protection Study reports benefits in patients with non-cardiac occlusive disease.

CONCLUSIONS

There is substantial evidence advocating the use of statins in patients with clinically significant vascular disease. In the future this may evolve to include those patients at risk from neointimal hyperplasia, aneurysmal disease and ischaemia reperfusion injury.

Chronic treatment with fluvastatin improves smooth muscle dilatory function in genetically determined hyperlipoproteinemia

We hypothesized that the HMG-CoA reductase inhibitor fluvastatin, does not only improve endothelium-dependent vasorelaxation, but that it also increases vascular smooth muscle reactivity in hyperlipoproteinemia. New Zealand White (NZW) rabbits aged 37 weeks (control), Watanabe Heritable Hyperlipidemic rabbits (WHHL) aged 37 weeks, and WHHL aged 35 weeks with fluvastatin treatment of 17 weeks (10 mg/kg/d) were examined. Aortas were isolated for isometric tension recording. Both endothelium-dependent and independent relaxation were impaired in WHHL. Fluvastatin significantly restored impaired endothelium-independent relaxation (WHHL: 57 +/- 12 versus WHHL+ fluvastatin: 150 +/- 22%; P < 0.05) and in tendency endothelium-dependent relaxation (WHHL: 26 +/- 5 versus WHHL+ fluvastatin: 83 +/- 29%; (P = 0.07)). In parallel, fluvastatin restored nitrite plasma level in hyperlipoproteinemic animals (WHHL: 480 (13-3821) versus WHHL+ fluvastatin: 808 (467-1595) nmol; P < 0.05). Thus, chronic treatment with fluvastatin not only improves endothelial but also vascular smooth muscle function in hyperlipoproteinemia, which may contribute to the beneficial clinical effects of statins.

Lovastatin induces relaxation and inhibits L-type Ca(2+) current in the rat basilar artery

Statins inhibit cholesterol biosynthesis and protect against ischaemic stroke. It has become increasingly apparent that the beneficial effects of statin therapy may extend beyond lowering of serum cholesterol. The present study was done to explore possible pleiotropic statin effects at the level of the cerebral vascular smooth muscle. Lovastatin, lovastatin acid, simvastatin and pravastatin, were added to segments of the rat basilar artery and effects on contraction and Ca2+ handling were examined. Pravastatin had no effect on contraction. Simvastatin, lovastatin, and, to a lesser degree, lovastatin acid, caused relaxation (IC50=0.8, 1.9 and 22 micromol/l) of both intact and denuded arteries precontracted with 5-HT or high-K+. This effect was not reversed by mevalonate, suggesting that it was not related to cholesterol or isoprenoid metabolism. Relaxation was associated with a reduction of the intracellular Ca2+ concentration measured with Fura 2 and with a reduced Mn2+ quench rate, suggesting a direct effect on ion channels in the smooth muscle cell membrane. Current measurements in isolated and voltage clamped basilar artery muscle cells demonstrated that both lovastatin and lovastatin acid inhibit L-type Ca2+ current. We propose that lipophilicity is an important factor behind the effects of statins on vascular tone and that Ca2+ current inhibition is the likely mechanism of action.

Effects of atorvastatin on vascular remodeling in spontaneously hypertensive rats

OBJECTIVE

To investigate the structural changes of aorta, and evaluate the effects of atorvastatin on the remodeling of thoracic aorta in spontaneously hypertensive rats (SHR).

METHODS

Twelve eight-week-old SHR were randomized into atorvastatin treated group (ATV group, n=6) and distilled water group (DW group, n=6); Wistar-Kyoto rats (WKY) were used as normal controls. Atorvastatin was administered to ATV group for 10 weeks by gavage in mixture with distilled water (1 ml); the latter two groups were given the same amount of distilled water by gavage for 10 weeks. Systolic blood pressure of caudal artery was examined before and after treatment, and serum concentrations of total cholesterol, triglycerides and HDL-C were measured. Wall thickness, media thickness, medial cross-sectional area and lumen diameter of thoracic aorta were assessed with computed video processing.

RESULTS

Systolic blood pressure in ATV group was markedly lower than that in DW group (P<0.01). Compared with DW group and WKY group, serum concentrations of total cholesterol, triglycerides and HDL-C in ATV group were significantly lower (P<0.01,P<0.05). Wall thickness, media thickness, and medial cross-sectional area to lumen ratio in DW group were significantly higher than those in WKY group and ATV group (P<0.01,P<0.05), but no such difference was found between WKY group and ATV group (P>0.05).

CONCLUSION

Vascular structural changes of aorta are due to the alteration of the vessel wall in early stage of SHR. Atorvastatin can markedly improve vascular remodeling.

Increased endothelin-induced Ca2+ signaling, tyrosine phosphorylation, and coronary artery disease in diabetic dyslipidemic Swine are prevented by atorvastatin

Endothelin-1 (ET-1) signaling mechanisms have been implicated in the pathogenesis of excess coronary artery disease in diabetic dyslipidemia. We hypothesized that in diabetic dyslipidemia ET-1-induced coronary smooth muscle calcium (Ca2+m) and tyrosine phosphorylation would be increased, and the lipid lowering agent, atorvastatin, would inhibit these increases. Male Yucatan miniature swine groups were treated for 20 weeks: normal low-fat fed control, high-fat/cholesterol fed (hyperlipidemic), hyperlipidemic made diabetic with alloxan (diabetic dyslipidemic), and diabetic dyslipidemic treated with atorvastatin (atorvastatin-treated). Blood glucose values were 5-fold greater in diabetic dyslipidemic and atorvastatin-treated versus control and hyperlipidemic. Total and low-density lipoprotein (LDL) plasma cholesterol in hyperlipidemic, diabetic dyslipidemic, and atorvastatin-treated were approximately 5-fold greater than control. Intravascular ultrasound detectable coronary disease and hypertriglyceridemia were only observed in diabetic dyslipidemic and were abolished by atorvastatin. In freshly isolated cells, the Ca2+m response to ET-1 in diabetic dyslipidemic was greater than in control, hyperlipidemic, and atorvastatin-treated groups. Selective ET-1 receptor antagonists showed in the control group that the ETB subtype inhibits ETA regulation of Ca2+m. There was almost a complete switch of receptor subtype regulation of Ca2+m from largely ETA in control to an increased inhibitory interaction between ETA and ETB in hyperlipidemic and diabetic dyslipidemic groups, such that neither ETA nor ETB antagonist alone could block the ET-1-induced Ca2+m response. The inhibitory interaction was attenuated in the atorvastatin-treated group. In single cells, basal and ET-1-induced tyrosine phosphorylation in diabetic dyslipidemic were more than 3- and 6-fold greater, respectively, than in control, hyperlipidemic, and atorvastatin-treated. Attenuation by atorvastatin of coronary disease and ET-1-induced Ca2+m and tyrosine phosphorylation signaling with no change in cholesterol provides strong evidence for direct actions of atorvastatin and/or triglycerides on the vascular wall.

Acute vasodilator effects of HMG-CoA reductase inhibitors: involvement of PI3-kinase/Akt pathway and Kv channels

3-hydroxy-3-methylglutaryl Coenzyme A (HMG-CoA) reductase inhibitors (statins) have several non-lipid-lowering actions; however, characteristics of their acute vasodilator effects remain to be elucidated. In this study, acute vasodilator effects of statins were examined in isolated rat blood vessels. After incubation with cerivastatin (1 microM) for 2 hours, acetylcholine-induced endothelium-dependent relaxations were enhanced in the rat aorta. This effect was abolished by a nitric oxide synthase (NOS) inhibitor, L-NNA, and by a PI3 kinase inhibitor, LY294002. Western blot analysis showed that the extent of phosphorylation of Akt, an active form of Akt, was increased by cerivastatin while it was reduced by LY294002, suggesting an involvement of PI3 kinase/Akt-dependent activation of endothelial NOS. At higher concentrations (1-300 microM), both cerivastatin and fluvastatin, but not pravastatin, directly relaxed the blood vessels, regardless of the presence or absence of the endothelium. These relaxations were abolished by KCl and were significantly inhibited by an inhibitor of Kv channel, 4-aminopyridine. These results indicate that multiple mechanisms are involved in the acute vasodilator effects of statins, including augmentation of nitric oxide-mediated endothelium-dependent relaxations through the PI3 kinase/Akt pathway and endothelium-independent relaxations via Kv channel-mediated smooth muscle hyperpolarizations. These acute vasodilator effects of statins may account, at least in part, for their beneficial effects on cardiovascular diseases associated with impaired organ blood flow.

[The statins: new properties]]

The comparison of major statin trials with trials using either cholestyramine or ileal bypass has suggested that the reduction in coronary heart disease events for those patients receiving statin therapy largely result from their low density lipoprotein (LDL)-cholesterol lowering action. LDL-cholesterol lowering has several physiological consequences, including plaque stabilisation with a decrease in the inflammatory process, slowing of plaque progression, and improvement of endothelial function, as evidenced by the measurement of endothelial-dependent vasorelaxation in response to hyperhaemia or acetylcholine infusion. Statins lower C-reactive protein without any consistent effect on the other inflammation acute phase proteins. The cause and consequences of this effect are still debated. In order to explain why some statins can prevent coronary events within a few months, a direct effect of this therapy on thrombosis has also been advocated; however, the evaluation of statin antithrombotic effects in humans has produced conflicting results. By inhibiting L-mevalonic acid synthesis, statins also prevent the farnelysation of small-GTP binding proteins such as Rho and Ras. In vitro, and in animal models, the inhibition of Rho with statins results in a decrease in endothelial nitric oxide production, an inhibition of leucocyte adhesion on endothelium, decrease in PPAR alpha activation and high density lipoprotein (HDL) production by the hepatocyte, decrease in Ca2+ stores in vascular smooth cells, and a stimulation of vascular smooth muscle cell apoptosis. However, most of these effects were obtained with high statin concentrations. Further evidence is needed before a full assessment of the clinical importance of isoprenylation blockage with therapeutic concentrations of statins in humans can be made.

Increased atherosclerosis in diabetic dyslipidemic swine: protection by atorvastatin involves decreased VLDL triglycerides but minimal effects on the lipoprotein profile

Male Yucatan swine were allocated to four groups (n = 5-6 pigs per group): low fat (3%) fed control, high fat/2% cholesterol (CH) fed (HF), high fat/CH fed with alloxan-induced diabetes (DF) and DF pigs that were treated with atorvastatin (80 mg/day; DF+A). Pigs were fed two meals per day and daily insulin injections were used in diabetic pigs to maintain plasma glucose between 250 and 350 mg/dl. Diabetic dyslipidemic (DF) pigs exhibited greater coronary atherosclerosis and increased collagen deposition in internal mammary artery compared with normoglycemic hyperlipidemic pigs. Although total and LDL CH concentrations did not differ, triglyceride (TG) were increased in DF pigs and FPLC analysis indicated that the LDL/HDL CH ratio was significantly increased in DF compared with HF pigs. The LDL fraction of DF pigs contained larger, lipid enriched particles resembling IDL. Consumption of the high fat/CH diet caused a moderate increase in the percentage of 14:0 fatty acids in plasma lipids and this was compensated by small-moderate declines in several unsaturated fatty acids. There was a significant increase in phospholipid arachidonic acid in DF compared with HF pigs. Atorvastatin protected diabetic pigs from atherosclerosis and decreased total and VLDL TG, but exerted minimal effects on the FPLC lipoprotein and plasma fatty acid profiles and plasma concentrations of total and LDL CH, vitamin A, vitamin E, and lysophosphatidylcholine. Across all groups the plasma CH concentration was positively correlated with hepatic CH concentration. These findings suggest that atorvastatin's protection against coronary artery atherosclerosis in diabetes may involve effects on plasma VLDL TG concentration. Lack of major effects on other lipid parameters, including the LDL/HDL ratio, suggests that atorvastatin may have yet other anti-atherogenic effects, possibly directly in the vessel wall.

Atorvastatin treatment prevents alterations in coronary smooth muscle nuclear Ca2+ signaling in diabetic dyslipidemia

Atorvastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, alters bulk myoplasmic Ca2+ regulation and inhibits phenotypic modulation and proliferation of vascular smooth muscle in culture. Nuclear Ca2+ (Ca(n)) signaling is tightly coupled to transcriptional events and cell growth. Therefore, we hypothesized that in vivo treatment with atorvastatin would attenuate alterations in mitogen-induced Ca(n) signaling associated with coronary atherosclerosis. Three groups of male Yucatan pigs were treated for 20 weeks: controls, alloxan-induced diabetics fed an atherogenic diet and diabetics fed an atherogenic diet plus atorvastatin (80 mg/day). Right coronary artery single-cell cytosolic Ca2+ (Ca(c)) and Ca(n) responses to the mitogen endothelin-1 (5 x 10(-8) M) were measured by laser confocal microscopy using the calcium indicator Fluo-4. We observed a 39% increase in Ca(c) and a 52% increase in Ca(n) responses to endothelin-1 in cells from diabetic dyslipidemic arteries compared to control. These alterations were prevented in animals treated with atorvastatin. We show that during proliferation, the nucleus of a smooth muscle cell becomes rounded and loses the characteristic multilobular shape, clefts and invaginations. Consistent with this, a redistribution of Ca2+ stores from a transnuclear morphology in controls to a more perinuclear morphology occurred in cells from diabetic dyslipidemic arteries and was prevented by atorvastatin. In addition, the peak Ca(n) responses to endothelin-1 were inversely correlated (r = 0.712) with the extent of the transnuclear distribution of Ca2+ stores and directly correlated (r = 0.874) with the extent of atherosclerosis, as assessed in vivo by intravascular ultrasound. These findings indicate that chronic treatment with atorvastatin directly decreases mitogen-induced Ca(n) mobilization, which we suggest is related to the spatial localization of Ca(n) stores.

Treatment with atorvastatin to the National Cholesterol Educational Program goal versus 'usual' care in secondary coronary heart disease prevention. The GREek Atorvastatin and Coronary-heart-disease Evaluation (GREACE) study

BACKGROUND

Atorvastatin is very effective in reducing plasma low-density lipoprotein cholesterol (LDL-C) levels. However, there is no long-term survival study that evaluated this statin.

PATIENTS-METHODS

To assess the effect of atorvastatin on morbidity and mortality (total and coronary) of patients with established coronary heart disease (CHD), 1600 consecutive patients were randomised either to atorvastatin or to 'usual' medical care. The dose of atorvastatin was titrated from 10 to 80 mg/day, in order to reach the National Cholesterol Education Program (NCEP) goal of LDL-C <100 mg/dl (2.6 mmol/l). All patients were followed up for a mean period of 3 years.

MAIN OUTCOME MEASURES

Primary endpoints of the study were defined as death, non-fatal myocardial infarction, unstable angina, congestive heart failure, revascularisation (coronary morbidity) and stroke. Secondary endpoints were the safety and efficacy of the hypolipidaemic drugs as well as the cost-effectiveness of atorvastatin.

RESULTS

The mean dosage of atorvastatin was 24 mg/day. This statin reduced total chlesterol by 36%, LDL-C by 46%, triglycerides by 31%, and non-high-density lipoprotein cholesterol (non-HDL-C) by 44%, while it increased HDL-C by 7%; all these changes were significant. The NCEP LDL-C and non-HDL-C treatment goals were reached by 95% (n = 759) and 97% (n = 776), respectively, of patients on atorvastatin. Only 14% of the 'usual' care patients received any hypolipidaemic drugs throughout the study and 3% of them reached the NCEP LDL-C treatment goal. The cost per quaility-adjusted life-year gained with atorvastatin was estimated at $US 8350. During this study 196 (24.5%) CHD patients on 'usual' care had a CHD recurrent event or died vs. 96 (12%) CHD patients on atorvastatin; risk ratio (RR) 0.49, confidence interval (CI) 0.27-0.73, p < 0.0001. In detail, atorvastatin reduced, in comparison to 'usual' care, total mortality (RR 0.57, CI 0.39-0.78, p = 0.0021), coronary mortality (RR 0.53, CI 0.29-0.74, p = 0.0017), coronary morbidity (RR 0.46, CI 0.25-0.71, p < 0.0001), and stroke (RR 0.53, CI 0.30-0.82, p = 0.034). All subgroups of patients (women, those with diabetes mellitus, arterial hypertension, age 60 to 75 years, congestive heart failure, recent unstable angina or prior revascularisation) benefited from treatment with atorvastatin. Withdrawal of patients because of side-effects from the atorvastatin group was low (0.75%) and similar to that of the 'usual' care group (0.4%).

CONCLUSIONS

Long-term treatment of CHD patients with atorvastatin to achieve NCEP lipid targets significantly reduces total and coronary mortality, coronary morbidity and stroke, in comparison to patients receiving 'usual' medical care. Treatment with atorvastatin is well tolerated and cost-effective.

Effect of atorvastatin on intracellular calcium uptake in coronary smooth muscle cells from diabetic pigs fed an atherogenic diet

Intracellular Ca(2+) store loading has been shown to alter proliferation and apoptosis of several cell types. In addition, HMG-CoA reductase inhibitors (i.e. atorvastatin) are effective in treating diabetic dyslipidemic patients. Thus, we hypothesized that chronic atorvastatin treatment would prevent increased Ca(2+) uptake into intracellular Ca(2+) stores in vascular smooth muscle cells from diabetic dyslipidemic pigs. Male Yucatan pigs were divided into four groups for 20 weeks-- (1) low fat fed (control); (2) hyperlipidemic (F); (3) alloxan-induced diabetic dyslipidemic (DF); and (4) diabetic dyslipidemic pigs treated with atorvastatin (DFA). The F, DF, and DFA groups were fed a high fat/cholesterol diet. Cells were isolated from the coronary artery and the myoplasmic Ca(2+) (Ca(m)) response measured using single cell fura-2 imaging. The Ca(m) response to caffeine (5 mM to release Ca(2+) from the sarcoplasmic reticulum, SR) and ionomycin (10 microM; to release the total Ca(2+) store) was determined in either the presence of low Na (19Na; inhibits Na(+)-Ca(2+) exchange), thapsigargin (TSG; inhibits the SR Ca(2+) pump), and a 19Na+TSG solution. Low Na induced the uptake of Ca(2+) into both SR and non-SR Ca(2+) stores in the DF group, but not the DFA group. Furthermore, after depletion of the SR Ca(2+) store with TSG, 19Na evoked Ca(2+) uptake into non-SR Ca(2+) stores in all three groups except in the DFA group. In summary, this study demonstrates that atorvastatin prevents the enhanced uptake of Ca(2+) by SR and non-SR Ca(2+) stores in diabetic dyslipidemic pigs.

Design and rationale of the ARBITER trial (Arterial Biology for the Investigation of the Treatment Effects of Reducing Cholesterol)--a randomized trial comparing the effects of atorvastatin and pravastatin on carotid artery intima-media thickness

BACKGROUND

As a class, statins are remarkably effective in reducing low-density lipoprotein (LDL) cholesterol, and several of these drugs have now been shown to reduce coronary heart disease morbidity and mortality. However, several important controversies in the use of statins remain to be answered by clinical trials. For example, it is controversial whether marked cholesterol reduction to levels below 100 mg/dL would further reduce the incidence of coronary heart disease. Furthermore, concerns about differences among statins for nonlipid effects has raised the concern that the assumption of a class effect is premature until head-to-head clinical trials are completed.

METHODS

Arterial Biology for the Investigation for the Treatment Effects of Reducing Cholesterol (ARBITER) is a single-center, randomized, active-controlled study comparing the efficacy of high-dose atorvastatin (80 mg/d) and pravastatin (40 mg/d) in patients being treated for either the primary or secondary prevention of coronary heart disease. This trial will enroll up to 200 patients for the primary end point of the mean change in intima-media thickness of the common carotid artery. This effect will be evaluated over a treatment duration of 12 months. Secondary end points include the effects of statin therapy on inflammatory and hemostatic markers (C-reactive protein and fibrinogen).

CONCLUSION

ARBITER will provide important data on the role of marked LDL reduction and the "class effect" theory of statin therapy in cardiovascular medicine.

Effect of simvastatin on vascular smooth muscle responsiveness: involvement of Ca(2+) homeostasis

This report is focused on the study of simvastatin-induced relaxation of rat aorta through its effects on vascular smooth muscle and Ca(2+) signalling. The presence of endothelium affected only the simvastatin-induced relaxation of aortic rings precontracted with noradrenaline, but not by depolarization with KCl 80 mM. Blockade of Ca(2+) entry through voltage-operated Ca(2+) channels (VOCCs) by diltiazem abolished the endothelium-dependent and direct relaxation, whereas Ca(2+)-ATPase inhibition by cyclopiazonic acid (3 x 10(-5) M) only affected the endothelium-dependent relaxation. In KCl-depolarised arteries concentration-response curves for CaCl(2) were shifted to the right in the presence of simvastatin (3 x 10(-6) and 3 x 10(-5) M) or diltiazem (10(-6) and 10(-7) M). The transient contraction caused by noradrenaline in Ca(2+)-free medium, which is mainly due to intracellular Ca(2+) release, was inhibited by simvastatin (3 x 10(-5) M) or cyclopiazonic acid (3 x 10(-5) M) and the contraction induced by CaCl(2) (2 x 10(-3) M) added after noradrenaline was inhibited by diltiazem and simvastatin. All the reported effects of simvastatin were inhibited by the product of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, mevalonate (10(-3) M). These findings demonstrate that the vascular effects of simvastatin may involve both Ca(2+) release from intracellular stores, which could promote activation of endothelial factors, and blockade of extracellular Ca(2+) entry, which promote relaxations independent of the presence of endothelium. This action on Ca(2+) could be related to the inhibition of isoprenoid synthesis, which subsequently affects the function of G-proteins involved in communication among intracellular Ca(2+) pools and capacitative Ca(2+) entry.

Use of statins and blood pressure control in treated hypertensive patients with hypercholesterolemia

High serum cholesterol has been frequently reported in patients with arterial hypertension in whom it might influence the blood pressure control. The aim of this study was to compare the extent of blood pressure changes in 41 patients with hypertension and hypercholesterolemia, taking antihypertensive drugs and treated for 3 months with statins (HC-S; pravastatin or simvastatin) and compared with matched controls with high (HC-D; 44) or normal serum cholesterol (NC-D; 45) undergoing antihypertensive treatment combined with dietary treatment alone. After 3 months of follow-up, a greater reduction of systolic (SBP) and diastolic (DBP) blood pressure values was observed in HC-S patients (ASBP/DBP, -11.3 +/-3/-10.6 +/- 2%) when compared with both HC-D (deltaSBP/DBP, -6.6 +/- 2/-6.1 +/- 2%; p < 0.05) and NC-D (deltaSBP/DBP, -6.9 +/- 2/-6.8 +/- 1.5%; p < 0.05). In statin-treated patients, a slight linear relation has been found between the percentage changes in DBP and those in plasma total cholesterol (R = 0.37, p = 0.043), whereas no relation was found with SBP changes (R =0.11; p = 0.35). In conclusion, the results of this study demonstrate that the use of statins in combination with antihypertensive drugs can improve blood pressure control in patients with uncontrolled hypertension and high serum cholesterol levels. The additional blood pressure reduction observed in patients treated with statins is clinically relevant and only partially related to the lipid-lowering effect.