Inhibitory effects of fluvastatin, a new HMG-CoA reductase inhibitor, on the increase in vascular ACE activity in cholesterol-fed rabbits

The renin-angiotensin system in the synovium promotes periarticular osteopenia in a rat model of collagen-induced arthritis

Periarticular osteopenia is the most specific hallmark of rheumatoid arthritis (RA). The renin-angiotensin system (RAS) in the synovium has been found to participate in the pathogenic process of RA. This study examined whether and how RAS regulates periarticular osteopenia in RA. The synovial tissues from patients with RA and osteoarthritis (OA) were prepared. Female Sprague-Dawley rats were treated with either saline, bovine type II collagen (CII) to induce arthritis (CIA), or CII combined with perindopril, an inhibitor of angiotensin-converting enzyme (ACE). Expressions of RAS components, including AT1R, AT2R and ACE, in human and rat synovial tissues were detected. Bone mass of rat joints was examined. Levels of RANKL, OPG and DKK-1 in rat synovium and expressions of TRAF6 and β-catenin in rat bone were examined. The results showed that AT1R, AT2R and ACE in human and rat synovium were up-regulated, but the increased ACE in rat synovial tissues was abrogated by perindopril. While CIA rats displayed increased bone resorption and decreased bone formation, perindopril treatment almost completely abrogated the RAS-mediated osteopenia, indicating that inhibition of ACE reduced the joint damages in rats. The expressions of RANKL and DKK-1 increased in CIA rats as compared with those in the control; TRAF6 was up-regulated and β-catenin was down-regulated in the bone tissues of CIA rats. The changes were then reversed by the use of perindopril. Our findings demonstrate that RAS in the synovium promotes periarticular osteopenia by increasing bone resorption and decreasing bone formation through modulating the RANKL/RANK/TRAF6 and Wnt/β-catenin pathways.

Statin therapy increases vascular sensitivity to angiotensin II in hypercholesterolaemic patients

Introduction Cross-talk between various cardiovascular risk factors has been suggested by a number of studies. This study examines the interaction between hypercholesterolaemia and the renin-angiotensin system in vivo in man.

Methods We performed a randomised, placebo-controlled, double-blind crossover study on 40 hypercholesterolaemic patients, comparing cholesterol-lowering therapy with a statin for six months versus placebo. Brachial artery function was assessed by bilateral venous occlusion plethysmography using intra-arterial infusions of the endothelial-dependent vasoconstrictors, angiotensin I (Ang I) and angiotensin II (Ang II), to measure vascular angiotensin-converting enzyme (ACE) and Ang II receptor response respectively. The endothelial-independent vasoconstrictor, noradrenaline, was used as a control vasoconstrictor. Results were analysed by multiple analysis of variance and statistical significance

Cholesterol-lowering treatment with a statin was taken as a p value <0.05. Results Cholesterol-lowering treatment with alstatin significantly reduced the mean total cholesterol level to 5.71 mmol/L vs. 7.57 mmol/L on placebo (p<0.0001). Hypercholesterolaemia significantly increased the vasoconstriction response to noradrenaline (placebo versus statin treatment; p=0.046). In hypercholesterolaemia, there was a strong trend towards a reduction in the vasoconstriction response to Ang I (placebo versus statin treatment; p=0.089). In hypercholesterolaemia, the vasoconstriction response to Ang II was significantly reduced (placebo versus statin treatment; p=0.01).

Conclusions Our in vivo results show that, unlike some other previous work, hypercholesterolaemia is associated with down-regulation of the vasoconstrictor response to Ang II and that statin therapy up-regulates the local vasoconstrictor response to Ang II. The possibility now arises that, in man, statins alter the balance between AT1-receptors and AT2-receptors.

Local renin-angiotensin system is associated with bone mineral density of glucocorticoid-induced osteoporosis patients

The local renin-angiotensin system (RAS) is closely related to bone metabolism. However, it is unknown whether the local RAS is related to bone mineral density (BMD) in glucocorticoid-induced osteoporosis (GIOP). Here, we revealed that the two main characteristics of GIOP might inhibit bone formation and enhance bone resorption.

INTRODUCTION

The aim of this study is to assess the expression of the main RAS components in the trabecular bone of lumbar vertebrae in GIOP and analyze the relationship between the major RAS components and BMD.

METHODS

We collected 96 inpatient cases of lumbar disc herniation from patients who underwent dual-energy X-ray absorptiometry examinations followed by surgical treatment in our hospital. Patients were divided into the GIOP group (n = 48) and control group (n = 48). The circulating and local expression levels of the main RAS components were examined. The correlation between the main RAS components and BMD was then analyzed.

RESULTS

The mRNA expression of local bone angiotensin type 1 and 2 receptors (AT1R and AT2R, respectively) and RANKL was higher in the GIOP group compared with the control group (p < 0.001), but there was no difference in the circulating protein levels between groups (p > 0.05). Multiple logistic regression analysis revealed that AT1R and AT2R expression and the RANKL/OPG ratio in local bone were negatively associated with BMD (p < 0.001, odds ratio (OR) 1.236, 95 % confidence interval (CI) 1.207-1.333; p < 0.001, OR 1.971, 95% CI 1.809-2.233; and p < 0.001, OR 1.676, 95% CI 1.546-1.845, respectively).

CONCLUSION

This study provides evidence that the role of local RAS is related to BMD in GIOP patients, and suggests that local RAS might influence RANKL/OPG signaling to modulate bone metabolism.

Phenolic compounds from sandpaper (ficus exasperata) leaf inhibits angiotensin 1 converting enzyme in high cholesterol diet fed rats

ETHNOPHARMACOLOGICAL RELEVANCE

Sandpaper [Ficus exasperata Vahl (Moraceae)] leaf has been reportedly used in folklore for the management/treatment of cardiovascular diseases with little/or no scientific basis for their action. This study sought to investigate the effect of dietary supplementation of sandpaper leaf on angiotensin-I converting enzyme (ACE) activity in hypercholesterolemia as well as the effect of their phenolic extract on this enzyme in vitro.

MATERIALS AND METHODS

The phenolic extract was prepared, then, the inhibitory effect of the leaf extract on ACE was determined in vitro. Thereafter, the effect of dietary supplementation of sandpaper leaf on angiotensin-I converting enzyme (ACE) activity in high cholesterol diet fed rats for 14 days was evaluated as well as some biochemical parameters.

RESULTS

The result revealed that under in vitro condition, the phenolic extract inhibited ACE (IC50=14.7µg/mL) in a dose-dependent manner (0-10µg/mL). Feeding high cholesterol diets to rats caused a significant (P<0.05) increase in the ACE activity. However, there was a significant (P<0.05) decrease in the ACE activity as a result of supplementation with the sand paper leaves. Furthermore, there was a significant (P<0.05) increase in the plasma lipid profile with a concomitant increase in malondialdehyde (MDA) content in rat liver and heart tissues. However, supplementing the diet with sandpaper leaf (either 10% or 20%) caused a significant (P<0.05) decrease in the plasma total cholesterol (TC), triglyceride (TG), very low density lipoprotein-cholesterol (VLDL-C), and low-density lipoprotein-cholesterol levels (LDL-C), and in MDA content in the tissues. Conversely, supplementation caused a significant (P<0.05) increase in plasma high-density lipoprotein-cholesterol level when compared with the control diet. Reversed phase HPLC analysis of the extract revealed Quercitrin (43.7mg/g), chlorogenic acid (42.8mg/g) and caffeic acid (33.9mg/g) as the major phenolics in the leaf.

CONCLUSION

The inhibition of ACE activity and prevention of hypercholesterolemia by sandpaper leaf could be part of the possible mechanism underlying its anti-hypertensive property which could lay credence to its use in folk medicine. However, these activities may be directly/indirectly attributed to the polyphenolics present.

Glucocorticoids activate the local renin-angiotensin system in bone: possible mechanism for glucocorticoid-induced osteoporosis

Bone metabolism disorder has been identified to play a vital role in the pathogenesis of glucocorticoid-induced osteoporosis (GIOP). The local renin-angiotensin system (RAS) in bone is newly defined to be closely related to the bone metabolism. However, it is unknown whether the local RAS is involved in GIOP. Adult male New Zealand white rabbits were treated with saline, dexamethasone (DXM) alone, or DXM combined with perindopril. The expression of main RAS components in trabecular bone was examined at mRNA and/or protein levels. Bone metabolism was analyzed using dual-energy X-ray absorptiometry, histomorphometry, biomechanics, biochemical techniques, and quantitative RT-PCR. The expressions of local bone angiotensin II, angiotensin types 1 and 2 receptors, and angiotensin-converting enzyme at mRNA and/or protein levels increased when DXM-induced osteoporosis was present. Whereas, perindopril significantly blocked the activation of the local RAS and partially reversed GIOP. Mineralizing surface, mineral apposition rate, and bone formation rate were decreased by DXM, along with serum osteocalcin being downregulated. These changes were then reversed by the use of perindopril. Osteoclast number, osteoclast surface, and eroded surface increased after the administration of DXM, and urinary deoxypyridinoline was upregulated. These were also inhibited when perindopril was given. Quantitative RT-PCR using RNA isolated from the lumbar vertebrae revealed an increase in the SOST expression and a decrease in the Runx2 expression, whereas the receptor activator of nuclear factor-κB ligand/osteoprotegerin ratio and the expression of tartrate resistant acid phosphatase were increased, which were all inhibited by perindopril. The results of this study provide evidence for the role of local RAS is involved in GIOP, and GIOP may be ameliorated by blocking the activation of local RAS in the bone.

Role of the local bone renin‑angiotensin system in steroid‑induced osteonecrosis in rabbits

The specific pathogenesis of steroid‑induced osteonecrosis (ON) is yet to be elucidated and until recently effective prophylactic therapies have not been available. The local renin‑angiotensin system (RAS) exists in the bone and has an important role in local bone regulation. However, to the best of our knowledge, the interrelation between local bone RAS and steroid‑induced ON is yet to be investigated. In the present study, 45 rabbits were injected with a single intramuscular dose of 20 mg/kg methylprednisolone acetate (MPA) and were sacrificed 1 (group A), 2 (group B) and 3 (group C) weeks subsequent to MPA administration (n=15 per group). Ten rabbits were used as a control group (group N). The presence or absence of ON in the bilateral femoral heads was examined histopathologically. The mRNA and protein expression of components of the RAS, including angiotensin II (Ang II), angiotensin converting enzyme (ACE) and Ang II type 1 (AT1) and Ang II type 2 (AT2) receptors, were detected in the bone. Significant changes in Ang II, ACE, and AT1 and AT2 receptor expression were observed in the bone of the rabbits in the different groups. Moreover, the expression of Ang II and ACE was highest one week subsequent to administration of the glucocorticoid methylprednisolone and the expression of the AT1 and AT2 receptors was highest two weeks following methylprednisolone administration. ON occurs most significantly at three weeks following the administration of MPA in this animal model, thus the changes in Ang II, ACE and AT1 and AT2 receptor expression preceded this. The present study found that ON was strongly associated with the activation of the local bone RAS in rabbits.

Statins in heart failure: do we need another trial?

Statins lower serum cholesterol and are employed for primary and secondary prevention of cardiovascular events. Clinical evidence from observational studies, retrospective data, and post hoc analyses of data from large statin trials in various cardiovascular conditions, as well as small scale randomized trials, suggest survival and other outcome benefits for heart failure. Two recent large randomized controlled trials, however, appear to suggest statins do not have beneficial effects in heart failure. In addition to lowering cholesterol, statins are believed to have many pleotropic effects which could possibly influence the pathophysiology of heart failure. Following the two large trials, evidence from recent studies appears to support the use of statins in heart failure. This review discusses the role of statins in the pathophysiology of heart failure, current evidence for statin use in heart failure, and suggests directions for future research.

Atorvastatin treatment affects atrial ion currents and their tachycardia-induced remodeling in rabbits

AIMS

Atrial fibrillation (AF) leads to electrical atrial remodeling including alterations of various ion channels early after arrhythmia onset. The beneficial effects of statins in AF treatment due to their influence on oxidative stress and inflammation are discussed. Our hypothesis was that statins might also alter atrial ion currents and their early tachycardia-induced remodeling.

MAIN METHODS

Effects of an atorvastatin treatment (7 days) on atrial ion currents and their tachycardia-induced alterations were studied in a rabbit model of tachycardia-induced electrical remodeling (rapid atrial pacing (600 min) for 24 and 120 h). Ion currents (L-type calcium channel [I(Ca,L)], transient outward current [I(to)]) were measured using whole cell patch clamp method and were compared with previous experiments in untreated but also tachypaced animals.

KEY FINDINGS

Atorvastatin treatment alone decreased I(Ca,L) similar to rapid atrial pacing alone, currents were also further reduced by additional atrial tachypacing. I(to) and its pacing-induced down-regulation after 24 h were not influenced by atorvastatin treatment. However, I(to) was still reduced after 120 h in atorvastatin-treated animals and did not return to control values as expected.

SIGNIFICANCE

The present study establishes that an atorvastatin treatment can affect atrial ion currents and their tachycardia-induced remodeling in a rabbit model. These results show that-amongst other positive effects on oxidative stress and inflammation-the impact of statins on ion currents and their tachycardia-induced alterations might also play a role in "upstream" treatment of AF with HMG-CoA reductase inhibitors.

Statins: 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase inhibitors demonstrate anti-atherosclerotic character due to their antioxidant capacity

Atherosclerosis is a chronic inflammatory disease of multiple etiologies. It is associated with the accumulation of oxidized lipids in arterial lesions leading to coronary heart disease. 3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (commonly known as statins) are widely used in cardiovascular disease prevention to lower the cholesterol. The antioxidant activity of HMG-CoA reductase inhibitors was studied by lipid peroxidation inhibition assay, DPPH, and hydroxyl radical scavenging-activity methods. The lovastatin (93%) and simvastatin (96%) showed significant action of lipid peroxidation inhibition compared to other HMG-CoA reductase inhibitors. The DPPH radical and hydroxyl radical scavenging activity of simvastatin was 38% and 33%, respectively. The oxidative modification of serum lipid due to reactive oxygen species causes atherosclerosis. This study revealed the importance of lovastatin and simvastatin to prevent oxidative stress-related cardiovascular diseases.

Effects of Statin Therapy on the Development and Progression of Heart Failure: Mechanisms and Clinical Trials

BACKGROUND

Statin therapy has been shown to effectively lower low-density lipoprotein cholesterol levels and reduce cardiovascular events. Statins also appear to exert other favorable effects, including anti-inflammatory actions and improvement in endothelial function. Statin therapy may therefore yield important clinical benefits in patients with heart failure-a physiologic state characterized by systemic inflammation and endothelial dysfunction.

METHODS AND RESULTS

This review summarizes basic and clinical investigations regarding the role of statin therapy in heart failure, focusing on potential mechanisms and preliminary clinical data. There is now extensive evidence suggesting that statins improve endothelial function, inhibit neurohormonal activation, restore autonomic balance, reduce inflammation, and prevent ventricular remodeling. Retrospective and small-scale prospective studies suggest that statins prevent the development of heart failure and reduce mortality in patients with established HF.

CONCLUSION

Preliminary evidence supports a role for statins in improving surrogate markers and clinical outcomes in ischemic and nonischemic heart failure. Large-scale randomized clinical trials are needed to definitively address this important topic.

Pravastatin Prevents Myocardium from Ischemia-Induced Fibrosis by Protecting Vascular Endothelial Cells Exposed to Oxidative Stress

HYPOTHESIS

Statins potently prevents cardiac myocytes from acute ischemia besides chronic inhibition of cholesterol synthesis. We investigated how pravastatin preserves the cardiac function after myocardial infarction (MI).

METHODS

Echocardiographically comparing rats with myocardial ischemia (MI group) with those treated with pravastatin (MI/statin group), we found that cardiac contractility was statistically preserved in the MI/statin whereas it was deteriorated in MI group.

RESULTS

Histochemical analysis suggested that ischemia-induced cardiac fibrosis was prevented by pravastatin. Because there was no significant myocyte apoptosis reflecting myocytes loss between two groups, ischemia-induced interstitial fibrosis might affect the contractility.

CONCLUSION

We hypothesized that statin may directly affect vascular endothelial cells regulating blood supply to the myocardium rather than affecting myocytes. Pravastatin perturbed H2O2-induced endothelial NOS reduction and inhibited H2O2-increased caspase-3 activation in cultured vascular endothelial cells. These data suggested that pravastatin prevent cardiac dysfunction by acting on vascular endothelial cells. Furthermore, early administration of pravastatin to the patients during acute onset of myocardial infarction may be beneficial to prevent myocardial damage caused by fibrosis associated with ischemia.

Scleroderma renal crisis: new insights and developments

Scleroderma renal crisis (SRC) was once a uniformly fatal complication of systemic sclerosis (SSc). With the introduction of angiotensin-converting enzyme inhibitors as treatment, outcomes have improved significantly, though 39% to 50% of SSc patients who develop SRC continue to have poor outcomes, including permanent dialysis and death. Early recognition and treatment with angiotensin-converting enzyme inhibitors are important in the effective management of SRC, though given the continuing morbidity and mortality caused by SRC, they are clearly not sufficient. Newer therapies based on the pathophysiologic mechanisms underlying the development and perpetuation of SRC are needed. This article reviews the epidemiology, pathogenesis, risk factors, clinical features, and treatment of SRC, with an emphasis on recent insights and developments.

Conceptual foundations of the UCSD Statin Study: a randomized controlled trial assessing the impact of statins on cognition, behavior, and biochemistry

BACKGROUND

Statin cholesterol-lowering drugs are among the most prescribed drugs in the United States. Their cardiac benefits are substantial and well supported. However, there has been persistent controversy regarding possible favorable or adverse effects of statins or of cholesterol reduction on cognition, mood, and behavior (including aggressive or violent behavior).

METHODS

The literature pertaining to the relationship of cholesterol or statins to several noncardiac domains was reviewed, including the link between statins (or cholesterol) and cognition, aggression, and serotonin.

RESULTS

There are reasons to think both favorable and adverse effects of statins and low cholesterol on cognition may pertain; the balance of these factors requires further elucidation. A substantial body of literature links low cholesterol level to aggressive behavior; statin randomized trials have not supported a connection, but they have not been designed to address this issue. A limited number of reports suggest a connection between reduced cholesterol level and reduced serotonin level, but more information is needed with serotonin measures that are practical for clinical use. Whether lipophilic and hydrophilic statins differ in their impact should be assessed.

CONCLUSION

There is a strong need for randomized controlled trial data to more clearly establish the impact of hydrophilic and lipophilic statins on cognition, aggression, and serotonin, as well as on other measures relevant to risks and quality-of-life impact in noncardiac domains.

Protective effect of fluvastatin, an HMG-CoA reductase inhibitor, on the formation of 8-oxo-2'-deoxyguanosine in the nuclear DNA of hamster pancreas after a single administration of N-nitrosobis(2-oxopropyl)amine

We examined whether fluvastatin (FV), a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, has antioxidant activity against oxidative DNA damage to hamster pancreas induced by a chemical carcinogen, N-nitrosobis(2-oxopropyl)amine (BOP). Female Syrian golden hamsters were treated with FV by gastric intubation 30 min before BOP administration. Control animals were intubated with saline. Animals were injected subcutaneously with BOP (20 mg/kg body weight) or saline, and sacrificed 1 and 4 h later. The contents of 8-oxo-2'-deoxyguanosine (8-oxodG) in the nuclear DNA and thiobarbituric acid-reacting substances (TBARS) were measured in the pancreas and liver of hamsters. Treatment with more than 0.22 mg/kg body weight FV significantly inhibited the increase in 8-oxodG content induced by BOP treatment. The TBARS contents in pancreas changed similarly by intubation of FV. In the liver, the contents of 8-oxodG and TBARS were not affected by a single administration of BOP. The protective effect of FV was stronger than those of pravastatin and other antioxidants such as Trolox, ascorbic acid and green tea catechin. These results suggest that FV inhibits oxidative damage to DNA and lipids caused by reactive oxygen species formed through the metabolism of chemical carcinogens.

Preservation of endothelium-dependent and Nomega-nitro-L-arginine methyl ester- and indomethacin-resistant arterial relaxation in high-cholesterol-diet fed rabbits by treatment with fluvastatin, an HMG-CoA reductase inhibitor

This study was designed to test the hypothesis that fluvastatin preserves endothelium-dependent and nitric oxide (NO)-independent relaxations in arterial preparations from rabbits fed a high-cholesterol diet in the absence of any cholesterol-lowering action. Rabbits were fed a 0.5% high-cholesterol diet for 12 weeks and then fed the high-cholesterol diet with/without fluvastatin 2 mg/kg/d for an additional 8 weeks. Plasma total and LDL-cholesterol concentrations were not affected by fluvastatin treatment. Endothelium-dependent and NO-mediated relaxation elicited by acetylcholine and A23187 in both the thoracic aorta and femoral artery was impaired in the high-cholesterol group but not in the fluvastatin-treated group. Endothelium-independent relaxation elicited by sodium nitroprusside was similar among the 3 groups. Preincubation of thoracic aortas from each of the 3 groups with Nomega-nitro-L-arginine methyl ester (L-NAME) and indomethacin completely abolished the relaxant response to acetylcholine. In contrast, the maximal response to acetylcholine (1 microM) in femoral artery was only partially reversed in the presence of L-NAME and indomethacin. Fluvastatin treatment preserved the acetylcholine-induced L-NAME and indomethacin-resistant relaxation impaired in the femoral artery from the high-cholesterol diet group. These results suggest that fluvastatin treatment preserves endothelium-dependent, NO-independent function as well as NO-dependent function in absence of its lipid lowering-action.

Antioxidative effects of fluvastatin and its metabolites against DNA damage in streptozotocin-treated mice

Fluvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, and its metabolites have been reported to protect against oxidative DNA damage in vitro. Streptozotocin (STZ) has drawn attention as a potential source of oxidative stress that induces genotoxicity. In order to elucidate the antioxidative effects of fluvastatin in vivo, we investigated the effects of 7-day treatment with fluvastatin on DNA damage in STZ-treated mice, as well as the effects of the main fluvastatin metabolites (M2, M3 and M4) and other inhibitors of the same enzyme, pravastatin and simvastatin. Protective effects against DNA damage in the liver and kidney from STZ-treated mice were assessed by the single-cell gel electrophoresis assay, and by detecting 8-hydroxy-2'-deoxyguanosine. A single intraperitoneal injection of STZ (150 mg/kg) increased serum levels of glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and blood urea nitrogen (BUN), and also caused DNA damage in the liver and kidney. Fluvastatin and its metabolites prevented the STZ-induced elevation of DNA damage and inhibited the increase in serum levels of AST, ALT and BUN. Fluvastatin and its metabolites showed protective effects against DNA damage as potent as that of the reference antioxidants (ascorbic acid, trolox and probucol) though pravastatin and simvastatin still lacked protective activity. Fluvastatin protected the mice against STZ-induced DNA damage, and may reduce the risk of oxidative stress in vivo.

Dipeptidyl peptidase IV inhibition improves impaired glucose tolerance in high-fat diet-fed rats: study using a Fischer 344 rat substrain deficient in its enzyme activity

This study was performed to determine the effects of a high-fat diet on glucose metabolism after an oral glucose challenge in high-fat diet-fed dipeptidyl peptidase IV (DPP-IV) positive (+) and deficient (-) Fischer 344 (F344) rats and the effects of novel DPP-IV inhibitor NVP-DPP728 (1-[2-[(5-cyanopyridin-2-yl)amino]ethylamino]acetyl-2-cyano-(S)-pyrrolidine monohydrochloride salt) on glucose tolerance in high-fat diet-fed F344 rats. In DPP-IV(+) rats, a high-fat diet load caused impaired glucose tolerance, such as increases of plasma insulin and blood glucose concentrations after oral glucose challenge, compared with a standard chow-fed group. In contrast, no marked change in glucose tolerance was induced by the high-fat diet in DPP-IV(-) rats. Blood glucose concentrations in DPP-IV(-) rats after glucose challenge were significantly lower than in DPP-IV(+) rats under high-fat diet load conditions. In standard chow and high-fat diet-fed DPP-IV(+) rats, NVP-DPP728 significantly suppressed glucose excursions after glucose challenge by inhibiting the plasma DPP-IV activity, associated with the stimulation of early insulin secretion. NVP-DPP728 did not affect glucose tolerance in DPP-IV(-) rats under both conditions. These results indicate that the amelioration of glucose tolerance by NVP-DPP728 in DPP-IV(+) rats was directly due to the inhibition of plasma DPP-IV activity, which might be via the subsequent increase in endogenous incretin action.

Fluvastatin, a 3-hydroxy-3-methylglutaryl coenzyme a reductase inhibitor, attenuates left ventricular remodeling and failure after experimental myocardial infarction

BACKGROUND

Short-term administration of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, statins, has been shown to attenuate ischemia-reperfusion injury. However, the effects of long-term administration of statins on left ventricular (LV) remodeling and failure after myocardial infarction remain unknown.

METHODS AND RESULTS

Mice were subjected to coronary artery ligation and were treated for 4 weeks with vehicle or fluvastatin (10 mg/kg per day PO). Fluvastatin increased survival (61% versus 86%; P<0.05) without affecting the infarct size (52+/-2% versus 49+/-3%; P=NS). Fluvastatin not only attenuated LV dilatation but also decreased LV end-diastolic pressure and lung weight. Furthermore, it reduced cardiac myocyte hypertrophy and interstitial fibrosis of the noninfarcted LV and also improved LV ejection performance. LV matrix metalloproteinase (MMP)-2 and MMP-13 were increased in myocardial infarction, which was attenuated in fluvastatin-treated mice.

CONCLUSIONS

Fluvastatin increased survival in a murine model of postinfarct heart failure, which was associated with the amelioration of LV structural remodeling and contractile failure. Moreover, these effects were associated with the attenuation of increased MMP activity. Thus, long-term treatment with fluvastatin might be beneficial also in patients with heart failure and might improve their long-term survival.

Fluvastatin reduces modification of low-density lipoprotein in hyperlipidemic rabbit loaded with oxidative stress

The in vivo antioxidant effect of fluvastain, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, was investigated using Watanabe heritable hyperlipidemic (WHHL) rabbits subjected to nicotine-free cigarette smoke extracts as oxidative stress. Fluvastatin was given orally at doses of 10 and 30 mg/kg per day for 5 months. The cigarette smoke extracts were prepared by bubbling the gas phase of smoke into phosphate-buffered saline and was injected daily into the rabbit ear vein. The rabbits chronically treated with the cigarette smoke extracts showed an increase in plasma lipid peroxide levels, estimated as thiobarbituric acid-reactive substances. Oxidative modification of plasma low-density lipoprotein (LDL) was assessed by anion-exchange high-performance liquid chromatographic analysis, LDL susceptibility to oxidation, LDL incorporation into macrophages and thiobarbituric acid-reactive substances levels in LDL. Treatment with fluvastatin significantly reduced these effects induced by the cigarette smoke extracts in a dose-related manner and exerted a cholesterol-lowering effect. At the end of the experiment, the cigarette smoke extracts caused accumulation of cholesteryl ester in the thoracic aorta, while fluvastatin significantly prevented this accumulation. These results indicate that fluvastatin can exert an antioxidant effect in vivo, with a strong effect on oxidative stress such as smoking, a major risk factor of atherosclerosis.

Estrogen, statins, and polyunsaturated fatty acids: similarities in their actions and benefits-is there a common link?

OBJECTIVES

To investigate whether there is any common link between estrogen, statins, and polyunsaturated fatty acids (PUFAs), which have similar actions and benefits.

METHODS

To critically review the literature pertaining to the actions of estrogen, statins, and various PUFAs.

RESULTS

Estrogen, statins, and PUFAs enhance nitric oxide synthesis, suppress the production of proinflammatory cytokines such as tumor necrosis factor(alpha), interleukin-1, interleukin-2, and interleukin-6, show antioxidant-like and antiatherosclerotic properties, have neuroprotective actions, and by themselves or their products inhibit tumor cell proliferation and improve osteoporosis. Estrogen, statins, and PUFAs not only have similar actions but also appear to interact with each other. For instance, the binding of estrogen to its receptor on the cell membrane may be determined by its lipid content, statins and PUFAs inhibit 3-hydroxy-3-methylglutaryl coenzyme A reductase activity, statins influence the metabolism of PUFAs, and PUFA deficiency enhances 3-hydroxy-3-methylglutaryl coenzyme A reductase activity. Statins and PUFAs inhibit tumor cell proliferation, suppress ras activity, and may prevent neurodegeneration and improve cognitive functions such as learning and memory. This suggests that PUFAs might be mediators of the actions of statins. Estrogen boosts cognitive performance in women after menopause and may protect against Alzheimer's disease.

CONCLUSIONS

The common link between estrogen, statins, and PUFAs may be nitric oxide. Hence, a combination(s) of estrogen or its derivatives, statins, and various PUFAs may form a novel approach in the management of various conditions such as hyperlipidemias, coronary heart disease, atherosclerosis, osteoporosis, cancer, neurodegenerative conditions, and to improve memory.

The hypertension-lipid connection: insights into the relation between angiotensin II and cholesterol in atherogenesis

Clinical data and experimental studies have established the important role of abnormal lipid metabolism in the causation of atherosclerosis and enthroned the hydroxymethylglutaryl coenzyme reductase inhibitors (statins) as a mainstay in management of patients with coronary heart disease. However, emerging experimental data underline the role of vascular renin-angiotensin systems in mediating the early stages of vascular endothelial dysfunction and inflammation as prerequisites for unleashing the cascade of cellular and molecular events that lead to the deposition of foam cells and their eventual progression to the atherosclerotic plaque. We discuss here the biological effects of statins and angiotensin II in the evolution of atherogenesis, underscoring possible links between statins and angiotensin receptor blockers. From the assessment of the commonality of effects resulting from the nonlipidic actions of statins and angiotensin II on the process of atherogenesis, we develop the argument that dyslipidemia may influence the ability to control blood pressure in hypertensive subjects and hypothesize that the combined use of statins and blockers of the renin-angiotensin system may have an additive effect in the management of hypertensive subjects.

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.

Antioxidative effects of fluvastatin and its metabolites against oxidative DNA damage in mammalian cultured cells

We investigated the effects of fluvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, on reactive oxygen species (ROS) and on oxidative DNA damage in vitro, as well as the effects of the main fluvastatin metabolites (M2, M3, and M4) and other inhibitors of the same enzyme, pravastatin and simvastatin. The hydroxyl radical and the superoxide anion scavenging activities of fluvastatin and its metabolites were evaluated using an electron spin resonance spectrometer. Fluvastatin and its metabolites showed superoxide anion scavenging activity in the hypoxanthine-xanthine oxidase system and a strong scavenging effect on the hydroxyl radical produced from Fenton's reaction. Protective effects of fluvastatin on ROS-induced DNA damage of CHL/IU cells were assessed using the single-cell gel electrophoresis assay. CHL/IU cells were exposed to either hydrogen peroxide or t-butylhydroperoxide. Fluvastatin and its metabolites showed protective effects on DNA damage as potent as the reference antioxidants, ascorbic acid, trolox, and probucol, though pravastatin and simvastatin did not exert clear protective effects. These observations suggest that fluvastatin and its metabolites may have radical scavenging activity and the potential to protect cells against oxidative DNA damage. Furthermore, ROS are thought to play a major role in the etiology of a wide variety of diseases such as cellular aging, inflammation, diabetes, and cancer development, so fluvastatin might reduce these risks.

Clinical pharmacokinetics of fluvastatin

Fluvastatin, the first fully synthetic HMG-CoA reductase inhibitor, has been shown to reduce cholesterol in patients with hyperlipidaemia, to prevent subsequent coronary events in patients with established coronary heart disease, and to alter endothelial function and plaque stability in animal models. Fluvastatin is relatively hydrophilic, compared with the semisynthetic HMG-CoA reductase inhibitors, and, therefore, it is extensively absorbed from the gastrointestinal tract. After absorption, it is nearly completely extracted and metabolised in the liver to 2 hydroxylated metabolites and an N-desisopropyl metabolite, which are excreted in the bile. Approximately 95% of a dose is recovered in the faeces, with 60% of a dose recovered as the 3 metabolites. The 6-hydroxy and N-desisopropyl fluvastatin metabolites are exclusively generated by cytochrome P450 (CYP) 2C9 and do not accumulate in the blood. CYP2C9, CYP3A4, CYP2C8 and CYP2D6 form the 5-hydroxy fluvastatin metabolite. Because of its hydrophilic nature and extensive plasma protein binding, fluvastatin has a small volume of distribution with minimal concentrations in extrahepatic tissues. The pharmacokinetics of fluvastatin are not influenced by renal function, due to its extensive metabolism and biliary excretion; limited data in patients with cirrhosis suggest a 30% reduction in oral clearance. Age and gender do not appear to affect the disposition of fluvastatin. CYP3A4 inhibitors (erythromycin, ketoconazole and itraconazole) have no effect on fluvastatin pharmacokinetics, in contrast to other HMG-CoA reductase inhibitors which are primarily metabolised by CYP3A and are subject to potential drug interactions with CYP3A inhibitors. Coadministration of fluvastatin with gastrointestinal agents such as cholestyramine, and gastric acid regulating agents (H2 receptor antagonists and proton pump inhibitors), significantly alters fluvastatin disposition by decreasing and increasing bioavailability, respectively. The nonspecific CYP inducer rifampicin (rifampin) significantly increases fluvastatin oral clearance. In addition to being a CYP2C9 substrate, fluvastatin demonstrates inhibitory effects on this isoenzyme in vitro and in vivo. In human liver microsomes, fluvastatin significantly inhibits the hydroxylation of 2 CYP2C9 substrates, tolbutamide and diclofenac. The oral clearances of the CYP2C9 substrates diclofenac, tolbutamide, glibenclamide (glyburide) and losartan are reduced by 15 to 25% when coadministered with fluvastatin. These alterations have not been shown to be clinically significant. There are inadequate data evaluating the potential interaction of fluvastatin with warfarin and phenytoin, 2 CYP2C9 substrates with a narrow therapeutic index, and caution is recommended when using fluvastatin with these agents. Fluvastatin does not appear to have a significant effect on other CYP isoenzymes or P-glycoprotein-mediated transport in vivo.

Determination of fluvastatin and its five metabolites in human plasma using simple gradient reversed-phase high-performance liquid chromatography with ultraviolet detection

A simple gradient reversed-phase high-performance chromatographic method with ultraviolet detection for the determination of fluvastatin (FV) and its five metabolites, (M-2, M-3, M4, M-5 and M-7) in human plasma was developed and validated. The limit of quantification of FV and its five metabolites in human plasma was 10 ng ml(-1). The assay had satisfactory selectivity, recovery, linearity and precision accuracy. Stability studies showed that FV and its five metabolites were stable in plasma up to at least 1 month of storage at -30 degrees C.

Protective effect of fluvastatin on degradation of apolipoprotein B by a radical reaction in human plasma

Fluvastatin, which is a synthetic 3-hydroxy-3-methylglutaryl coenzyme (HMG-CoA) reductase inhibitor, its metabolites (M2, M3 and M4) and trolox all inhibited the decrease of apolipoprotein B-100 (apoB) and alpha-tocopherol in a radical reaction of human plasma initiated by Cu2+. The concentrations of fluvastatin, M2, M3, M4 and trolox for 50% inhibition (IC50) of apoB fragmentation were 405, 8.55, 1.75, 305, and 43.4 microM, respectively. The IC50 value of pravastatin, which is another HMG-CoA reductase inhibitor, was 2880 microM, showing that pravastatin is not an effective antioxidant. Although fluvastatin, its metabolites and trolox inhibited the decrease of alpha-tocopherol in a similar manner to that of apoB, pravastatin did not significantly inhibit the decrease of alpha-tocopherol. Since oxidation of low density lipopotein (LDL) is an important step in the initiation and progression of atherosclerosis, fluvastatin may reduce the risk of atherosclerosis not only by lowering plasma cholesterol but also by protecting LDL from oxidation.

Protective effects of fluvastatin against reactive oxygen species induced DNA damage and mutagenesis

Oxidative stress may be an important factor in the development of diabetic complications. Advanced glycation end-products have drown attention as potential sources of oxidative stress in diabetes. We investigated the protective effects of fluvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, on oxidative DNA damage from reactive oxygen species or advanced glycation end-products in vitro, as well as effects of main fluvastatin metabolites and other inhibitors of the same enzyme, pravastatin and simvastatin. Protective effects were assessed in terms of the DNA breakage rate in a single-stranded phage DNA system in vitro. DNA was exposed to either reactive oxygen species or advanced glycation end-products. Fluvastatin and its metabolites showed a strong protective effect comparable to those seen with thiourea and mannitol, though pravastatin and simvastatin did not exert clear protective effects. Furthermore, fluvastatin reduced the mutagenesis by reactive oxygen species or advanced glycation end-products in Salmonella typhimurium test strains. Both pravastatin and simvastatin still lacked protective activity. Fluvastatin and its metabolites protect against oxidative DNA damage and may reduce risk of consequent diabetic complications.

Fluvastatin normalizes the decreased turnovers of glutathione and ascorbic acid in Watanabe heritable hyperlipidaemic rabbits

1. Fluvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, has been reported to decrease the oxidizability of plasma lipids in hyperlipidaemic subjects. In order to elucidate one of the mechanisms of this in vivo, we investigated the effects of fluvastatin and pravastatin on the decreased turnovers of reduced glutathione (GSH) and ascorbic acid (AA) in Watanabe heritable hyperlipidaemic (WHHL) rabbits. 2. These drugs (30 mg/kg per day) equally decreased plasma levels of lipids after a 4 week treatment period. However, only fluvastatin significantly decreased thiobarbituric acid-reactive substances, which were increased in the plasma of WHHL. 3. Although these drugs did not affect the steady state levels of total glutathione and low molecular weight thiols in the liver and kidney, fluvastatin markedly normalized the rate of GSH turnover in these tissues, as determined by using L-buthionine-(S,R)-sulphoximine, a specific inhibitor of GSH synthesis. 4. Fluvastatin also increased the clearance of AA from the circulation in WHHL. 5. These results suggest that, in addition to its hypolipidaemic action, fluvastatin has the potential to improve the turnover of anti-oxidants, which is closely related to the amelioration of the redox status in the body.

Fluvastatin: effects beyond cholesterol lowering

Coronary heart disease (CHD) remains a major therapeutic challenge in the Western world, and strategies aimed at cholesterol lowering form the mainstay of treatment. Fluvastatin is an established 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor ("statin") for the treatment of hypercholesterolemia. Its efficacy and safety have been established in numerous clinical trials. Emerging evidence now indicates that treatment with fluvastatin slows the progression of atherosclerotic CHD and reduces the incidence of cardiovascular morbimortality in the secondary prevention setting. This effect of fluvastatin cannot be explained by cholesterol lowering alone; nonlipid-related mechanisms (so-called "pleiotropic effects") undoubtedly contribute to a certain extent, and are probably linked to modulation of the mevalonate pathway. This review discusses the experimental evidence regarding the antiatherosclerotic and antithrombotic effects of fluvastatin that may contribute to its beneficial action on disease progression and clinical events. Such effects include decreased expression of adhesion molecules in monocytes and leucocyte-endothelium adherence responses, immunomodulation, prevention of low-density lipoprotein oxidation, inhibition of cholesterol esterification and accumulation, along with effects on smooth muscle cell proliferation and migration. Pleiotropic actions aimed at plaque stabilization (eg, decreased secretion of matrix metalloproteinases by macrophages), together with effects on platelet activity, tissue factor expression, and endothelial function, may contribute to an antithrombotic effect of fluvastatin. Taken together, the results of these studies indicate that the effects of fluvastatin, at therapeutic doses, may extend beyond cholesterol lowering.

Functional evidence for anti-oxidant action of fluvastatin on low-density lipoprotein using isolated macrophages and aorta

1. Fluvastatin has been reported to have not only a hypocholesterolaemic effect, but also a protective effect on low-density lipoprotein (LDL) from oxidation. We functionally evaluated the anti-oxidant effect of fluvastatin on oxidation of LDL by copper ions in vitro using mouse macrophages and rabbit aorta preparations. 2. After native LDL (N-LDL) from rabbit plasma had been pre-incubated in the presence or absence of fluvastatin (10 micromol/L) for 4 h, the N-LDL was mildly oxidized by incubation with 5 micromol/L CuCl2 for 5 h and two oxidized LDL, fluvastatin-pretreated (Flu-OxLDL) and -non-treated (OxLDL), were prepared. The level of thiobarbituric acid-reactive substances (TBARS) in Flu-OxLDL and OxLDL markedly increased compared with N-LDL. The degree of increment was significantly less in Flu-OxLDL than OxLDL. 3. When macrophages were incubated with Flu-OxLDL or OxLDL, the amount of cholesteryl ester that accumulated in the macrophages markedly increased compared with N-LDL. The degree of increment was significantly less in Flu-OxLDL than OxLDL. 4. Acetylcholine-induced endothelium-dependent relaxations in rabbit aortic rings were impaired in the presence of either Flu-OxLDL or OxLDL. The degree of impairment was significantly less in Flu-OxLDL. 5. The increased TBARS level, facilitated cholesteryl ester accumulation in macrophages and impaired endothelium-dependent relaxation elicited by OxLDL were not affected by simultaneous treatment with fluvastatin (10 micromol/L). 6. These findings indicate that fluvastatin can protect plasma LDL from oxidative modification and, thereby, prevent cholesterol accumulation in macrophages and endothelial dysfunction in blood vessels. This additional anti-oxidative effect of fluvastatin may be beneficial for preventing the progression of atherosclerosis.

Increases of vascular endothelin-converting enzyme activity and endothelin-1 level on atherosclerotic lesions in hyperlipidemic rabbits

The aim of this study was to investigate vascular endothelin-converting enzyme activity and the tissue level of endothelin-1 in the aorta related to atherosclerotic lesions in high cholesterol diet-fed rabbits. Rabbits were fed two atherogenic diets, 0.5% and 1.5% cholesterol, and a normal diet for 16 weeks. Vascular endothelin-converting enzyme activity in the aortic arch and thoracic aorta was significantly increased (2.0-4.4 times) by the atherogenic diet as compared with the normal diet group as well as the levels of lipids and lipid peroxide in plasma were significantly increased. Tissue endothelin-1 levels in both aortas were also elevated (2.3-6.8 times), corresponding well to the increased tissue enzyme activity. In contrast, plasma endothelin-1 levels increased only in the 1.5% cholesterol diet group (2.7 times). These results indicate that the endothelin-converting enzyme activity and the corresponding endothelin-1 level in the vascular walls increase in association with the development of atherosclerotic lesions.

Do pleiotropic effects of statins beyond lipid alterations exist in vivo? What are they and how do they differ between statins?

The inhibition of cellular proliferation, the restoration of endothelial activity, the inhibition of platelet reactivity, and an antioxidant potential are only a few examples of pleiotropic effects of statins. This review analyzes the current knowledge on the pleiotropic properties of this class of drugs and examines the relevant data that support the presence of these effects in vivo. The favorable outcome of major trials of statins has indicated that pleiotropic factors indeed play a role in cardiovascular protection. In addition, recent data indicate that many pleiotropic effects influence mechanisms that belong to the extravascular compartment, as well. Perhaps, some of these properties may eventually justify additional indications for statins and improve the treatment of other diseases, including inflammation and cancer.

Fluvastatin suppresses atherosclerotic progression, mediated through its inhibitory effect on endothelial dysfunction, lipid peroxidation, and macrophage deposition

Fluvastatin, a potent 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, exerts an inhibitory effect on intimal thickening after mechanical injury in normocholesterolemic rabbit artery at a dose not enough to elicit a known action of lipid lowering. This study was designed to determine whether atherosclerotic progression triggered by hypercholesterolemia can be inhibited by fluvastatin under conditions without its hypocholesterolemic effect. Rabbits were fed a 0.5% cholesterol diet or normal diet for 17 weeks and were treated with either fluvastatin (0.3-2 mg/kg/day, p.o.) or pravastatin (2 mg/kg/day, p.o.). Atherogenic features manifested in the cholesterol-diet group, compared with the normal-diet group; they were the increase in serum lipid peroxide level, in the intraluminal lesion area of the aorta, and in macrophage content of the aortic cross-sectional lesion area; the attenuation of endothelium-dependent relaxing response to acetylcholine in the femoral artery; and the increase in serum lipid level. Treatment with fluvastatin, but not pravastatin, inhibited the manifestation of the atherogenic features without a serum lipid-lowering effect. Thus fluvastatin is likely to reduce the risk of atherosclerotic progression, to which endothelial dysfunction, lipid peroxidation, and macrophage accumulation in the vasculature may contribute, irrespective of changes in serum lipid levels.

Simvastatin inhibits cardiac hypertrophy and angiotensin-converting enzyme activity in rats with aortic stenosis

1. In the present study, we tested the hypothesis that long-term administration of the hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor simvastatin may regress hypertrophy and the possible effect of simvastatin on angiotensin-converting enzyme (ACE) activity in rats with pressure-overload cardiac hypertrophy. 2. Pressure-overload left ventricular hypertrophy (LVH) of rats was induced by part coarctation of the abdominal aorta; a sham-operated group served as the control. Six weeks after operation, animals were divided into three groups and an 8 week treatment period was insitgated as follows: (i) the simvastatin treatment group received simvastatin at 3.6 mg/kg per day, p.o.; (ii) the ACE inhibitor group received captopril at 50 mg/kg per day, p.o.; and (iii) the LVH control group received no drug treatment. 3. At the end of the treatment period, left ventricular systolic pressure (LVSP) and left ventricular end-diastolic pressure (LVEDP) were monitored in vivo. Diastolic pressure-volume relationships were evaluated in a Langendorff preparation with a balloon-in-left ventricle (LV) heart. Myocyte cell width was measured. Angiotensin-converting enzyme activity and angiotensin (Ang)II and hydroxyproline contents of the LV were determined. 4. At the end of the experiments, LVH was established in the LVH control group by increases in LV weight, LV weight/body-weight ratio, LV weight/right ventricle weight ratio, LV myocyte cell width, LVSP and LVEDP by 40, 26, 19, 61, 56 and 59%, respectively (all P < 0.01), compared with the sham-operated group. In the simvastatin-treated and ACE inhibitor groups all these parameters were significantly reduced compared with sham-operated controls. In the LVH control group, ACE activity and AngII and hydroxyproline contents of LV tissue increased by 180, 123 and 70, respectively (all P < 0.01), compared with the sham-operated group. Compared with the LVH group, in the simvastatin-treated and ACE inhibitor groups ACE activity was reduced by 36 (P < 0.05) and 48% (P < 0.01), respectively, AngII content was reduced by 11 (P < 0.05) and 43% (P < 0.01), respectively, and hydroxyproline content was reduced by 23 (P < 0.01) and 10% (P < 0.05), respectively. 5. For the first time, the results of the present study demonstrate that simvastatin significantly reduces LVH, cardiac tissue ACE activity and improves LV performance in pressure-overloaded rats. Because, compared with captopril, simvastatin is more potent in its reduction of LVH and less potent in its inhibition of ACE activity, the mechanism of its antihypertrophic action, in addition to ACE inhibition, may involve inhibition of the mevalonic acid pathway, the main target of action of statins. Thus, HMG-CoA reductase inhibitors may be beneficial for the clinical treatment of cardiac hypertrophy.

State-of-the-Art lecture. Statins and blockers of the renin-angiotensin system: vascular protection beyond their primary mode of action

In addition to their primary mode of action, statins and blockers of the renin-angiotensin system possess common additional properties that are under active investigation. The inhibition of cellular proliferation, the restoration of endothelial activity, the inhibition of platelet reactivity, and an antioxidant potential are only a few examples of shared effects that target the arterial wall. These and other properties may eventually become exploited for the improved treatment of cardiovascular diseases and of other diseases apparently unrelated to the cardiovascular field, including inflammation and cancer. This review analyzes the current knowledge on the pleiotropic properties of these classes of drugs. Direct comparison indicates that study of the associations among these drugs may eventually disclose additive or synergistic effects that, perhaps even at lower dosages, may provide improved vascular protection and a strong alliance against several atherogenic mechanisms.

Post-stroke treatment with imidapril reduces learning deficits with less formation of brain oedema in a stroke-prone substrain of spontaneously hypertensive rats

The present study was undertaken to examine the effects of the ACE (angiotensin converting enzyme) inhibitor imidapril, on the brain, when administered after the onset of stroke in a stroke-prone substrain of spontaneously hypertensive rats (SHRSP). Learning deficits and induced lesions in the brain as well as in the kidneys and heart were investigated in detail. SHRSP were divided into two groups with or without salt loading at the age of 4 weeks. The salt loading was performed for 7-9 weeks to increase the incidence of stroke. Within 24 h after the first observation of stroke, animals were subsequently treated with 5 mg/kg imidapril orally once a day or the vehicle for up to the age of 27 weeks. Imidapril attenuated progression of neurological abnormalities such as irritability, hyperkinesia and motor dysfunction, and increased survival rate. In three-panel runway testing, learning deficits did not develop significantly in the imidapril-treated group, and was comparable to that in the non-salt-loaded/non-stroke group. Imidapril reduced oedema formation in the cortex, hippocampus and striatum, and also suppressed lesion formation in the kidneys and heart. Imidapril thus suppressed progression of neurological deficits with loss of learning ability following onset of stroke, and also suppressed formation of oedema in the brain and decreased the number of lesions in other organs. Imidapril-induced reduction of cerebrovascular damage, which presumably occurs in the brain after stroke, may account for the inhibitory effects of imidapril on lesion formation and learning impairment.

Antiatherosclerotic activity of drugs in relation to nitric oxide function

Many studies have shown that loss of endothelium-derived nitric oxide is a major factor of ischemic episodes in patients with coronary artery disease and there is increasing evidence to suggest that nitric oxide might exert antiatherosclerotic actions. Based on these concepts, the results of animal studies on the effects of lipid lowering drugs, antioxidants, angiotensin converting enzyme inhibitors, Ca2+ channel blockers, estrogens and agents which modulate nitric oxide bioavailability are presented and compared to the results of patient studies and clinical trials. In spite of encouraging results obtained with antioxidants in animals, clinical trials could only show a clear positive effect of vitamin E treatment on the outcome of cardiovascular disease. Angiotensin converting enzyme inhibitors can ameliorate endothelial dysfunction in coronary heart disease, but their impact on disease progression remains unclear. There is evidence that estrogen replacement therapy in post-menopausal women may increase the bioavailability of nitric oxide. Finally, improved endothelial function and plaque stability clearly contribute to the clinical benefits of lipid lowering interventions, statins in particular. Taken together, these studies lend support to the concept that improving endothelial function and nitric oxide release might serve as valuable elements in the prevention or therapy of cardiovascular disease.

Fluvastatin: a review of its use in lipid disorders

Fluvastatin is an HMG-CoA reductase inhibitor used to treat patients with hypercholesterolaemia. Since fluvastatin was last reviewed in Drugs, trials have shown its efficacy in the secondary prevention of coronary heart disease (CHD) events and death and have expanded knowledge of its effects in primary CHD prevention and its mechanisms of activity. In addition to reducing total (TC) and low density lipoprotein (LDL-C) cholesterol, fluvastatin has antiatherogenic, antithrombotic and antioxidant effects, can improve vascular function, and may have immunomodulatory effects. Although fluvastatin interacts with bile acid sequestrants (requiring separation of doses), its pharmacokinetics permit oral administration to most patient groups. Fluvastatin is well tolerated, with adverse effects usually mild and transient. Use of fluvastatin to reduce lipids in patients with primary hypercholesterolaemia is well established. Its effects are similar in most patient groups, with 20 to 80 mg/day reducing LDL-C by 22 to 36%, triglycerides (TG) by 12 to 18% and apolipoprotein B by 19 to 28% and increasing high density lipoprotein cholesterol by 3.3 to 5.6%. Attempts to find fluvastatin dosages with efficacy equivalent to that of other HMG-CoA reductase inhibitors produce variable results, but larger per-milligram fluvastatin dosages are needed when patients switch from other HMG-CoA reductase inhibitors. Combinations of fluvastatin with fibric acid derivatives and bile acid sequestrants produce additive effects. Small noncomparative studies suggest fluvastatin reduces LDL-C in patients with hypercholesterolaemia secondary to kidney disorders by < or = 40.5% and with type 2 diabetes mellitus by < or = 32%. Three large randomised, double-blind trials show fluvastatin can help prevent CHD events or death and slow disease progression in patients with CHD with or without hypercholesterolaemia. In the Fluvastatin Angiographic Restenosis trial in patients undergoing balloon angioplasty, fluvastatin 80 mg/day for 40 weeks reduced the postangioplasty rate of deaths plus myocardial infarctions (1.5% vs 4% with placebo, p < 0.025) without altering vessel luminal diameters. In the Lipoprotein and Coronary Atherosclerosis Study in patients with coronary artery stenosis, luminal diameter reduced to a significantly lesser extent after fluvastatin 20 mg twice daily than placebo after 2.5 years (-0.028 vs -0.01 mm, p < 0.005). The Lescol in Symptomatic Angina study found reductions in all cardiac events or cardiac death in patients after 1 year of fluvastatin 40 mg/day (1.6% vs 5.6% for placebo, p < 0.05).

CONCLUSIONS

An evolving pattern of data suggests that, in addition to its well established efficacy and cost effectiveness in reducing hypercholesterolaemia, fluvastatin may now also be considered for use in the secondary prevention of CHD.

Protective effect of fluvastatin sodium (XU-62-320), a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, on oxidative modification of human low-density lipoprotein in vitro

We investigated the protective effect of fluvastatin sodium on the oxidation of low-density lipoprotein (LDL) induced in vitro by copper ions. The extent of lipid peroxidation was assessed by monitoring the increase of UV absorbance at 234 nm, which is the peak absorbance of a conjugated diene. Fluvastatin sodium (1-30 microM) not only prolonged the lag time of oxidation in the initiation step, but also decreased the rate of oxidation in the propagation step, both concentration dependently. Fluvastatin sodium and alpha-tocopherol showed an additive effect when both compounds were added before oxidation. However, when the lag time was prolonged initially by alpha-tocopherol, and fluvastatin sodium and alpha-tocopherol, were further added into the reaction mixture at the end point of the lag phase, fluvastatin sodium still showed an antioxidative effect, whereas alpha-tocopherol showed a pro-oxidative effect. Therefore, the antioxidative property of fluvastatin sodium differs from that of alpha-tocopherol. In this experiment, as neither the double bond-reduced derivative of fluvastatin sodium nor pravastatin sodium showed any protective effect, we concluded that the antioxidative effect of fluvastatin sodium is not a common property of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, but may be derived from its unique chemical structure. Since the oxidative modification of LDL plays an important role in the genesis of atherosclerosis, fluvastatin sodium may help reduce the risk of atherosclerosis, not only by reducing plasma LDL levels but also by protecting LDL from oxidative modification.

Effects of fluvastatin on leukocyte-endothelial cell adhesion in hypercholesterolemic rats

The overall objective of this study was to determine whether peroral treatment with the 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase inhibitor fluvastatin influences the leukocyte-endothelial cell adhesion (LECA) observed in postcapillary venules of hypercholesterolemic rats. Rats were fed either normal chow or a chow supplemented with 1% cholesterol for 10 days. Leukocyte adherence and extravasation, leukocyte rolling velocity, red blood cell velocity, and vessel diameter were monitored in mesenteric venules superfused with either 100 nmol/L platelet-activating factor (PAF) or 20 nmol/L leukotriene B4 (LTB4). Hypercholesterolemic rats exhibited an exaggerated LECA response compared with their normocholesterolemic counterparts. In hypercholesterolemic rats, treatment with fluvastatin significantly attenuated the leukocyte-adherence responses to PAF and LTB4 as well as the leukocyte emigration response to LTB4. Fluvastatin treatment also inhibited the PAF- and LTB4-induced reductions in leukocyte rolling velocity. These findings indicate that fluvastatin blunts the inflammatory responses elicited in post-capillary venules by lipid mediators.