Rosuvastatin increases vascular endothelial PPARgamma expression and corrects blood pressure variability in obese dyslipidaemic mice

High doses of rosuvastatin induce impaired branched-chain amino acid catabolism and lead to insulin resistance

NEW FINDINGS

What is the central question of this study? Is there a risk of developing diabetes associated with statin treatment? What is the underlying mechanism of the increased incidence rate of new-onset diabetes in patients treated with rosuvastatin? What is the main finding and its importance? Rosuvastatin therapy reduced intraperitoneal glucose tolerance and changed the catabolism of branched-chain amino acid (BCAAs) in white adipose tissue and skeletal muscle. Protein phosphatase 2Cm knockdown completely abolished the effects of insulin and rosuvastatin on glucose absorption. This study provides mechanistic support for recent clinical data on rosuvastatin-related new-onset diabetes and underscores the logic for intervening in BCAA catabolism to prevent the harmful effects of rosuvastatin.

ABSTRACT

Accumulating evidence indicates that patients treated with rosuvastatin have an increased risk of developing new-onset diabetes. However, the underlying mechanism remains unclear. In this study, we administered rosuvastatin (10 mg/kg body weight) to male C57BL/6J mice for 12 weeks and found that oral rosuvastatin dramatically reduced intraperitoneal glucose tolerance. Rosuvastatin-treated mice showed considerably higher serum levels of branched-chain amino acids (BCAAs) than control mice. They also showed dramatically altered expression of BCAA catabolism-related enzymes in white adipose tissue and skeletal muscle, including downregulated mRNA expression of BCAT2 and protein phosphatase 2Cm (PP2Cm) and upregulated mRNA expression of branched-chain ketoacid dehydrogenase kinase (BCKDK). The levels of BCKD in the skeletal muscle were reduced in rosuvastatin-treated mice, which was associated with lower PP2Cm protein levels and increased BCKDK levels. We also investigated the effects of rosuvastatin and insulin administration on glucose metabolism and BCAA catabolism in C2C12 myoblasts. We observed that incubation with insulin enhanced glucose uptake and facilitated BCAA catabolism in C2C12 cells, which was accompanied by elevated Akt and glycogen synthase kinase 3 β (GSK3β) phosphorylation. These effects of insulin were prevented by co-incubation of the cells with 25 μM rosuvastatin. Moreover, the effects of insulin and rosuvastatin administration on glucose uptake and Akt and GSK3β signaling in C2C12 cells were abolished when PP2Cm was knocked down. Although the relevance of these data, obtained with high doses of rosuvastatin in mice, to therapeutic doses in humans remains to be elucidated, this study highlights a potential mechanism for the diabetogenic effects of rosuvastatin, and suggests that BCAA catabolism could be a pharmacological target for preventing the adverse effects of rosuvastatin.

Pharmacological Utility of PPAR Modulation for Angiogenesis in Cardiovascular Disease

Peroxisome proliferator activated receptors, including PPARα, PPARβ/δ, and PPARγ, are ligand-activated transcription factors belonging to the nuclear receptor superfamily. They play important roles in glucose and lipid metabolism and are also supposed to reduce inflammation and atherosclerosis. All PPARs are involved in angiogenesis, a process critically involved in cardiovascular pathology. Synthetic specific agonists exist for all PPARs. PPARα agonists (fibrates) are used to treat dyslipidemia by decreasing triglyceride and increasing high-density lipoprotein (HDL) levels. PPARγ agonists (thiazolidinediones) are used to treat Type 2 diabetes mellitus by improving insulin sensitivity. PPARα/γ (dual) agonists are supposed to treat both pathological conditions at once. In contrast, PPARβ/δ agonists are not in clinical use. Although activators of PPARs were initially considered to have favorable effects on the risk factors for cardiovascular disease, their cardiovascular safety is controversial. Here, we discuss the implications of PPARs in vascular biology regarding cardiac pathology and focus on the outcomes of clinical studies evaluating their benefits in cardiovascular diseases.

Long-term statins administration exacerbates diabetic nephropathy via ectopic fat deposition in diabetic mice

Statins play an important role in the treatment of diabetic nephropathy. Increasing attention has been given to the relationship between statins and insulin resistance, but many randomized controlled trials confirm that the therapeutic effects of statins on diabetic nephropathy are more beneficial than harmful. However, further confirmation of whether the beneficial effects of chronic statin administration on diabetic nephropathy outweigh the detrimental effects is urgently needed. Here, we find that long-term statin administration may increase insulin resistance, interfere with lipid metabolism, leads to inflammation and fibrosis, and ultimately fuel diabetic nephropathy progression in diabetic mice. Mechanistically, activation of insulin-regulated phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin signaling pathway leads to increased fatty acid synthesis. Furthermore, statins administration increases lipid uptake and inhibits fatty acid oxidation, leading to lipid deposition. Here we show that long-term statins administration exacerbates diabetic nephropathy via ectopic fat deposition in diabetic mice.

Visit-to-Visit Blood PressureVariations and Hemodynamic Deterioration in Atherosclerotic Major Cerebral ArteryDisease

OBJECTIVE

Visit-to-visit variations in blood pressure (BP) in patients with atherosclerotic major cerebral artery disease could impair the function of cerebral collaterals, leading to hemodynamic deterioration at follow-up. However, few studies have investigated the relationship between visit-to-visit BP variability and changes in hemodynamic parameters at follow-up.

MATERIALS AND METHODS

We evaluated 35 medically treated patients with atherosclerotic internal carotid artery or middle cerebral artery disease with no ischemic episodes during follow-up (mean: 35 ± 20 months); these patients had a three-time visit for positron emission tomography examinations with ¹⁵O-gas. Differences in the mean hemispheric values of hemodynamic parameters in the cortical territory of the diseased artery between the first and third examinations (changes at follow-up) were correlated with the coefficient of variation (CoV) in three systolic BP (SBP) values at the three examinations (BP variability during follow-up).

RESULTS

CoV values were negatively correlated with changes in oxygen metabolism or cerebral blood flow/cerebral blood volume (CBF/CBV) ratio. In 17 patients with higher CoV values (> group median, 0.072), decreases in CBF, cerebral metabolic rate of oxygen, and CBF/CBV ratio were observed at follow-up; CBV decreased in 18 patients without elevated CoV. A higher CoV was associated with a lack of statin use.

CONCLUSION

In patients with atherosclerotic major cerebral artery disease, high visit-to-visit SBP variations during follow-up may be associated with deterioration in cerebral hemodynamics and metabolism.

Oxidative Stress, GTPCH1, and Endothelial Nitric Oxide Synthase Uncoupling in Hypertension

Significance: Hypertension has major health consequences, which is associated with endothelial dysfunction. Endothelial nitric oxide synthase (eNOS)-produced nitric oxide (NO) signaling in the vasculature plays an important role in maintaining vascular homeostasis. Considering the importance of NO system, this review aims to provide a brief overview of the biochemistry of members of NO signaling, including GTPCH1 [guanosine 5'-triphosphate (GTP) cyclohydrolase 1], tetrahydrobiopterin (BH4), and eNOS. Recent Advances: Being NO signaling activators and regulators of eNOS signaling, BH4 treatment is getting widespread attention either as potential therapeutic agents or as preventive agents. Recent clinical trials also support that BH4 treatment could be considered a promising therapeutic in hypertension. Critical Issues: Under conditions of BH4 depletion, eNOS-generated superoxides trigger pathological events. Abnormalities in NO availability and BH4 deficiency lead to disturbed redox regulation causing pathological events. This disturbed signaling influences the development of systemic hypertension as well as pulmonary hypertension. Future Directions: Considering the importance of BH4 and NO to improve the translational significance, it is essential to continue research on this field to manipulate BH4 to increase the efficacy for treating hypertension. Thus, this review also examines the current state of knowledge on the effects of eNOS activators on preclinical models and humans to utilize this information for potential therapy.

Special bioactive compounds and functional foods may exhibit neuroprotective effects in patients with dementia (Review)

Dementia is a failure of cognitive ability characterized by severe neurodegeneration in select neural systems, and Alzheimer's disease (AD) is the most common type of neurodegenerative disease. Although numerous studies have provided insights into the pathogenesis of AD, the underlying signaling and molecular pathways mediating the progressive decline of cognitive function remain poorly understood. Recent progress in molecular biology has provided an improved understanding of the importance of molecular pathogenesis of AD, and has proposed an association between DNA repair mechanisms and AD. In particular, the fundamental roles of phosphatase and tensin homologue deleted on chromosome 10 (PTEN) and breast cancer gene 1 (BRCA1) tumor suppressors have been shown to regulate the pathogenesis of neurodegeneration. Consequently, onset of neurodegenerative diseases may be deferred with the use of dietary neuroprotective agents which alter the signaling mediated by the aforementioned tumor suppressors. In a healthy neuron, homeostasis of key intracellular molecules is of great importance, and preventing neuronal apoptosis is one of the primary goals of treatments designed for dementia-associated diseases. In the present review, progress into the understanding of dietary regulation for preventing or limiting development of dementia is discussed with a focus on the modulatory roles of PTEN and BRCA1 signaling.

Diet induces hepatocyte protection in fatty liver disease via modulation of PTEN signaling

Fatty liver disease (FLD) is characterized by accumulation of excess fat in the liver. The underlying molecular mechanism associated with the progression of the disease has been in elusive. Hepatocellular demise due to increased oxidative stress resulting in an inflammatory response may be a key feature in FLD. Recent advances in molecular biology have led to an improved understanding of the molecular pathogenesis, suggesting a critical association between the PI3K/AKT/PTEN signaling pathway and FLD. In particular, PTEN has been associated with regulating the pathogenesis of hepatocyte degeneration. Given the function of mitochondria in reactive oxygen species (ROS) generation and the initiation of oxidative stress, the mitochondrial antioxidant network is of interest. It is vital to balance the activity of intracellular key molecules to maintain a healthy liver. Consequently, onset of FLD may be delayed using dietary protective agents that alter PTEN signaling and reduce ROS levels. The advancement of research on dietary regulation with a focus on modulatory roles in ROS generation and PTEN associated signaling is summarized in the current study, supporting further preventive and therapeutic exploration.

Effects of statins on the chemoresistance-The antagonistic drug-drug interactions versus the anti-cancer effects

There has been growing interest in the potential anti-cancer activity of statins based on evidence of their anti-proliferative, pro-apoptotic, and radiosensitizing properties, but no studies have focused on the effects of statins on the chemoresistance. In spite of their direct cytostatic/cytotoxic effects on the cancer cells, statins via drug interactions may affect therapeutic effects of the chemotherapy agents and so cause chemoresistance in cancer cells. Here, we aim to present the molecular mechanisms underlying cytotoxic effects of statins on the cancer cells against those mechanisms by which statins may lead to chemoresistance, in order to clarify whether the positive effects of the co-treatment of statins on the efficiency of chemotherapeutic agents is due to the natural anti-cancer effects of statins or it is due to increasing the cellular concentrations of chemotherapy drugs in cancer cells.

Maternal Metabolism and Vascular Adaptation in Pregnancy: The PPAR Link

Current therapies for pregnancy-related hypertension and its complications remain inadequate, although an increasing role for maternal susceptibility is becoming evident. Systemic vascular dysfunction in response to imbalances in angiogenic, inflammatory, and constricting factors is implicated in the pathogenesis of gestational hypertension, and growing evidence now links these factors with maternal metabolism. In particular, the crucial role of peroxisome proliferator-activated receptors (PPARs) in maternal vascular adaptation provides further insights into how obesity and gestational diabetes may be linked to pregnancy-induced hypertension and preeclampsia. This is especially important given the rapidly growing prevalence of obesity during pregnancy, and highlights a new approach to treat pregnancy-related hypertension and its complications.

Combined sub-optimal doses of rosuvastatin and bexarotene impair angiotensin II-induced arterial mononuclear cell adhesion through inhibition of Nox5 signaling pathways and increased RXR/PPARα and RXR/PPARγ interactions

AIM

Mononuclear cell (MC) infiltration into the arterial subendothelium is a key event in atherogenesis. Rosuvastatin (Rosu) and bexarotene (Bex) exert anti-inflammatory activity, but serious dose-related adverse effects have emerged. The need for safer and effective strategies to prevent and treat atherosclerosis led us to test the effect of combined use of both drugs on angiotensin II (Ang-II)-induced arterial MC recruitment.

RESULTS

Vehicle, Rosu (10-30 nM), Bex (0.3-1 μM), or a combination of both were administered to human umbilical arterial endothelial cells (HUAECs) 20 h before stimulation with 1 μM Ang-II (4 h). Surprisingly, a combination of Rosu (10 nM)+Bex (0.3 μM), which did not influence Ang-II-induced MC recruitment when either stimulus was studied alone, significantly reduced this response. This effect was accompanied by diminished Ang-II-induced ICAM-1, VCAM-1, and CX3CL1 endothelial expression and CXCL1, CXCL8, CCL2, and CCL5 production. Preincubation of HUAECs with Rosu+Bex inhibited Nox5 expression and Nox5-induced RhoA activation stimulated by Ang-II through increased RXRα, PPARα, and PPARγ expression in addition to RXRα/PPARα and RXRα/PPARγ interactions. In vivo, combined but not single administration of Rosu (1.25 mg/kg/day) and Bex (10 mg/kg/day) significantly diminished Ang-II-induced arteriolar leukocyte adhesion in the cremasteric microcirculation of C57BL/6 mice and atherosclerotic lesion formation in apoE(-/-) mice subjected to an atherogenic diet.

INNOVATION AND CONCLUSION

Combined administration of Bex+Rosu at suboptimal doses may constitute a new alternative and effective therapy in the control of the vascular inflammation associated to cardiometabolic disorders, since they synergize in their anti-inflammatory actions and may counteract their associated adverse effects.

Circadian rhythms, Wnt/beta-catenin pathway and PPAR alpha/gamma profiles in diseases with primary or secondary cardiac dysfunction

Circadian clock mechanisms are far-from-equilibrium dissipative structures. Peroxisome proliferator-activated receptors (PPAR alpha, beta/delta, and gamma) play a key role in metabolic regulatory processes, particularly in heart muscle. Links between circadian rhythms (CRs) and PPARs have been established. Mammalian CRs involve at least two critical transcription factors, CLOCK and BMAL1 (Gekakis et al., 1998; Hogenesch et al., 1998). PPAR gamma plays a major role in both glucose and lipid metabolisms and presents circadian properties which coordinate the interplay between metabolism and CRs. PPAR gamma is a major component of the vascular clock. Vascular PPAR gamma is a peripheral regulator of cardiovascular rhythms controlling circadian variations in blood pressure and heart rate through BMAL1. We focused our review on diseases with abnormalities of CRs and with primary or secondary cardiac dysfunction. Moreover, these diseases presented changes in the Wnt/beta-catenin pathway and PPARs, according to two opposed profiles. Profile 1 was defined as follows: inactivation of the Wnt/beta-catenin pathway with increased expression of PPAR gamma. Profile 2 was defined as follows: activation of the Wnt/beta-catenin pathway with decreased expression of PPAR gamma. A typical profile 1 disease is arrhythmogenic right ventricular cardiomyopathy, a genetic cardiac disease which presents mutations of the desmosomal proteins and is mainly characterized by fatty acid accumulation in adult cardiomyocytes mainly in the right ventricle. The link between PPAR gamma dysfunction and desmosomal genetic mutations occurs via inactivation of the Wnt/beta-catenin pathway presenting oscillatory properties. A typical profile 2 disease is type 2 diabetes, with activation of the Wnt/beta-catenin pathway and decreased expression of PPAR gamma. CRs abnormalities are present in numerous pathologies such as cardiovascular diseases, sympathetic/parasympathetic dysfunction, hypertension, diabetes, neurodegenerative diseases, cancer which are often closely inter-related.

Low-density lipoprotein-cholesterol-induced endothelial dysfunction and oxidative stress: the role of statins

SIGNIFICANCE

Cardiovascular diseases (CVD) represent a major public health burden. High low-density lipoprotein (LDL)-cholesterol is a recognized pathogenic factor for atherosclerosis, and its complications and statins represent the most potent and widely used therapeutic approach to prevent and control these disorders.

RECENT ADVANCES

A number of clinical and experimental studies concur to identify endothelial dysfunction as a primary step in the development of atherosclerosis, as well as a risk factor for subsequent clinical events. Oxidant stress resulting from chronic elevation of plasma LDL-cholesterol (LDL-chol) is a major contributor to both endothelial dysfunction and its complications, for example, through alterations of endothelial nitric oxide signaling.

CRITICAL ISSUES

Statin treatment reduces morbidity and mortality of CVD, but increasing evidence questions that this is exclusively through reduction of plasma LDL-chol. The identification of ancillary effects on (cardio)vascular biology, for example, through their modulation of oxidative stress, will not only increase our understanding of their mechanisms of action, with a potential broadening of their indication(s), but also lead to the identification of new molecular targets for future therapeutic developments in CVD.

FUTURE DIRECTIONS

Further characterization of molecular pathways targeted by statins, for example, not directly mediated by changes in plasma lipid concentrations, should enable a more comprehensive approach to the pathogenesis of (cardio)vascular disease, including, for example, epigenetic regulation and fine tuning of cell metabolism.

HMGCoA reductase inhibition reverses myocardial fibrosis and diastolic dysfunction through AMP-activated protein kinase activation in a mouse model of metabolic syndrome

AIMS

The metabolic syndrome (MS) leads to myocardial fibrosis (MF) and diastolic dysfunction. Statins have proven beneficial effects in MS, but their impact on cardiac remodelling is uncertain. We examined the effects and mechanisms of chronic statin treatment on cardiac remodelling, e.g. fibrosis and diastolic properties.

METHODS AND RESULTS

We used a mouse model deficient in leptin and the LDL-receptor (DKO) that reproduces this MS phenotype. DKO mice (12 weeks) were treated with rosuvastatin (R) for 6 months vs. placebo. Morphometric and echocardiographic measurements showed that R reduced cardiac mass and increased left-ventricular end-diastolic diameter despite unchanged cardiomyocyte dimensions. Similarly, R had no effect on the hypertrophic response to neurohormones in isolated cardiomyocytes. Conversely, R reversed the age-dependent development of MF as well as mRNA expression of TGF-β1 and several pro-fibrotic markers (procollagen type I, its carboxy-terminal proteinase, Lysyl oxidase). R similarly inhibited the pro-fibrotic effects of TGF-β1 on procollagen type I, alpha Smooth Muscle Actin expression and migratory properties of cardiac fibroblasts in vitro. In parallel, R increased the activation of AMP-activated protein kinase (AMPK), a known inhibitor of fibrosis, in vivo and in vitro, and the anti-fibrotic effects of R were abrogated in fibroblasts transfected with AMPKα1/α2 siRNA. The reversal of MF by R in DKO mice was accompanied with improved diastolic properties assessed by P-V loop analysis (slope of EDPVR, dP/dt min and cardiac output).

CONCLUSION

In this model of MS, statin treatment reverses myocardial remodelling and improves ventricular relaxation through AMPK-mediated anti-fibrotic effects.

Possible involvement of PPARγ-associated eNOS signaling activation in rosuvastatin-mediated prevention of nicotine-induced experimental vascular endothelial abnormalities

Nicotine exposure via cigarette smoking and tobacco chewing is associated with vascular complications. The present study investigated the effect of rosuvastatin in nicotine (2 mg/kg/day, i.p., 4 weeks)-induced vascular endothelial dysfunction (VED) in rats. The development of VED was assessed by employing isolated aortic ring preparation and estimating aortic and serum nitrite/nitrate concentration. Further, scanning electron microscopy and hematoxylin-eosin staining of thoracic aorta were performed to assess the vascular endothelial integrity. Moreover, oxidative stress was assessed by estimating aortic superoxide anion generation and serum thiobarbituric acid-reactive substances. The nicotine administration produced VED by markedly reducing acetylcholine-induced endothelium-dependent relaxation, impairing the integrity of vascular endothelium, decreasing aortic and serum nitrite/nitrate concentration, increasing oxidative stress, and inducing lipid alteration. However, treatment with rosuvastatin (10 mg/kg/day, i.p., 4 weeks) markedly attenuated nicotine-induced vascular endothelial abnormalities, oxidative stress, and lipid alteration. Interestingly, the co-administration of peroxisome proliferator-activated receptor γ (PPARγ) antagonist, GW9662 (1 mg/kg/day, i.p., 2 weeks) submaximally, significantly prevented rosuvastatin-induced improvement in vascular endothelial integrity, endothelium-dependent relaxation, and nitrite/nitrate concentration in rats administered nicotine. However, GW9662 co-administration did not affect rosuvastatin-associated vascular anti-oxidant and lipid-lowering effects. The incubation of aortic ring, isolated from rosuvastatin-treated nicotine-administered rats, with L-NAME (100 μM), an inhibitor of nitric oxide synthase (NOS), significantly attenuated rosuvastatin-induced improvement in acetylcholine-induced endothelium-dependent relaxation. Rosuvastatin prevents nicotine-induced vascular endothelial abnormalities by activating PPARγ and endothelial NOS signaling pathways. Moreover, the PPARγ-independent anti-oxidant and lipid-lowering effects of rosuvastatin might additionally play a role in the improvement of vascular endothelial function.

Submaximal PPARγ activation and endothelial dysfunction: new perspectives for the management of cardiovascular disorders

PPARγ activation plays an important role in glucose metabolism by enhancing insulin sensitization. PPARγ is a primary target for thiazolidinedione-structured insulin sensitizers like pioglitazone and rosiglitazone employed for the treatment of type 2 diabetes mellitus. Additionally, PPARγ activation inhibits adhesion cascades and detrimental vascular inflammatory events. Importantly, activation of PPARγ plays a distinctive role in regulating the physiology and expression of endothelial nitric oxide synthase (eNOS) in the endothelium, resulting in enhanced generation of vascular nitric oxide. The PPARγ activation-mediated vascular anti-inflammatory and direct endothelial functional regulatory actions could, therefore, be beneficial in improving the vascular function in patients with atherosclerosis and hypertension with or without diabetes mellitus. Despite the disappointing cardiac side effect profile of rosiglitazone-like PPARγ full agonists, the therapeutic potential of novel pharmacological agents targeting PPARγ submaximally cannot be ruled out. This review discusses the potential regulatory role of PPARγ on eNOS expression and activation in improving the function of vascular endothelium. We argue that partial/submaximal activation of PPARγ could be a major target for vascular endothelial functional improvement. Interestingly, newly synthesized partial agonists of PPARγ such as balaglitazone, MBX-102, MK-0533, PAR-1622, PAM-1616, KR-62776 and SPPARγM5 are devoid of or have a reduced tendency to cause the adverse effects associated with full agonists of PPARγ. We propose that the vascular protective properties of pharmacological agents, which submaximally activate PPARγ, should be investigated. Moreover, the therapeutic opportunities of agents that submaximally activate PPARγ in preventing vascular endothelial dysfunction (VED) and VED-associated cardiovascular disorders are discussed.

The antihypertensive actions of statins: modulation by salt intake

Hydroxy methyl glutaryl CoA inhibitors (statins) are the agents most frequently used to reduce elevated serum cholesterol. In addition to their cholesterol lowering effects, statins also have nonlipid lowering pleiotropic properties. These include reducing oxidative stress, renin-angiotensin and endothelin synthesis and activity, and improving nitric oxide (NO) synthesis and availability. Thus, one would predict that statins might be able to exert an antihypertensive effect. Experimental models bear out the blood pressure lowering effects but the data from clinical trials have been inconsistent perhaps due to inappropriate experimental designs, sample size, blood pressure measurement techniques etc. Moreover, although experimental models strongly suggest a role for salt intake in the potential antihypertensive responses to statins, available clinical trials fail to report salt intake in the studied populations. The statins' antihypertensive effects remain an unsettled hypothesis and calls for a large clinical trial at a wide range of doses and a controlled salt intake. Statins meanwhile remain as a excellent option to control high cholesterol and in tissue injury prevention.

Rho-associated coiled-coil-containing kinase 2 deficiency in bone marrow-derived cells leads to increased cholesterol efflux and decreased atherosclerosis

BACKGROUND

Macrophages play a central role in the development of atherosclerosis. However, the signaling pathways that regulate their function are not well understood. The Rho-associated coiled-coil-containing kinases (ROCK1 and ROCK2) are serine-threonine protein kinases that are involved in the regulation of the actin cytoskeleton. Recent studies suggest that ROCK1 in macrophages and bone marrow-derived cells mediates atherogenesis. However, a similar role for ROCK2 in the pathogenesis of atherosclerosis has not been determined.

METHODS AND RESULTS

The bone marrows from wild-type, ROCK2(+/-), and ROCK2(-/-) mice were transplanted into irradiated recipient low-density lipoprotein receptor(-/-) mice, and atherosclerosis was induced with a 16-week high-cholesterol diet. Compared with wild-type bone marrow-transplanted mice, ROCK2(+/-) bone marrow-transplanted and ROCK2(-/-) bone marrow-transplanted mice showed substantially less lipid accumulation in the aorta (8.46±1.42% and 9.80±2.34% versus 15.64±1.89%; P<0.01 for both) and decreased atherosclerotic lesions in the subaortic sinus (158.1±44.4 and 330.1±109.5×10(3)μm(2) versus 520.2±125.7×10(3)μm(2); P<0.01 for both). These findings correlated with decreased foam cell formation (2.27±0.57 versus 4.10±0.3; P<0.01) and increased cholesterol efflux (17.65±0.6 versus 9.75±0.8; P<0.05) in ROCK2-deficient mice that are mediated, in part, through the peroxisome proliferator-activated receptor-γ/liver X receptor/ATP-binding cassette transporter A1 pathway in macrophages.

CONCLUSIONS

ROCK2 contributes to atherosclerosis, in part, by inhibiting peroxisome proliferator-activated receptor-γ-mediated reverse cholesterol transport in macrophages, which contributes to foam cell formation. These findings suggest that inhibition of ROCK2 in macrophages may have therapeutic benefits in preventing the development of atherosclerosis.

The effect of rosuvastatin in a murine model of influenza A infection

RATIONALE

HMG-CoA reductase inhibitors such as rosuvastatin may have immunomodulatory and anti-inflammatory effects that may reduce the severity of influenza A infection. We hypothesized that rosuvastatin would decrease viral replication, attenuate lung injury, and improve mortality following influenza A infection in mice.

METHODS

C57Bl/6 mice were treated daily with rosuvastatin (10 mg/kg/day) supplemented in chow (or control chow) beginning three days prior to infection with either A//Udorn/72 [H3N2] or A/WSN/33 [H1N1] influenza A virus (1×10(5) pfu/mouse). Plaque assays were used to examine the effect of rosuvastatin on viral replication in vitro and in the lungs of infected mice. We measured cell count with differential, protein and cytokines in the bronchoalveolar lavage (BAL) fluid, histologic evidence of lung injury, and wet-to-dry ratio on Day 1, 2, 4, and 6. We also recorded daily weights and mortality.

RESULTS

The administration of rosuvastatin had no effect on viral clearance of influenza A after infection. Weight loss, lung inflammation and lung injury severity were similar in the rosuvastatin and control treated mice. In the mice infected with influenza A (A/WSN/33), mortality was unaffected by treatment with rosuvastatin.

CONCLUSIONS

Statins did not alter the replication of influenza A in vitro or enhance its clearance from the lung in vivo. Statins neither attenuated the severity of influenza A-induced lung injury nor had an effect on influenza A-related mortality. Our data suggest that the association between HMG CoA reductase inhibitors and improved outcomes in patients with sepsis and pneumonia are not attributable to their effects on influenza A infection.

Interplay between statins and PPARs in improving cardiovascular outcomes: a double-edged sword?

Statins are best-selling medications in the management of high cholesterol and associated cardiovascular complications. They inhibit 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA)-reductase in order to prevent disproportionate cholesterol synthesis. Statins slow the progression of atherosclerosis, prevent the secondary cardiovascular events and improve the cardiovascular outcomes in patients with elevated cholesterol levels. The underlying mechanisms pertaining to the cardioprotective role of statins are linked with numerous pleiotropic actions including inhibition of inflammatory events and improvement of endothelial function, besides an effective cholesterol-lowering ability. Intriguingly, recent studies suggest possible interplay between statins and nuclear transcription factors like PPARs, which should also be taken into consideration while analysing the potential of statins in the management of cardiovascular complications. It could be suggested that statins have two major roles: (i) a well-established cholesterol-lowering effect through inhibition of HMG-CoA-reductase; (ii) a newly explored PPAR-activating property, which could mediate most of cardiovascular protective pleiotropic effects of statins including anti-inflammatory, antioxidant and anti-fibrotic properties. The present review addressed the underlying principles pertaining to the modulatory role of statins on PPARs.

Rosuvastatin improves endothelial function in db/db mice: role of angiotensin II type 1 receptors and oxidative stress

BACKGROUND AND PURPOSE

HMG-CoA reductase inhibitors, statins, with lipid-reducing properties combat against atherosclerosis and diabetes. The favourable modulation of endothelial function may play a significant role in this effect. The present study aimed to investigate the cellular mechanisms responsible for the therapeutic benefits of rosuvastatin in ameliorating diabetes-associated endothelial dysfunction.

EXPERIMENTAL APPROACH

Twelve-week-old db/db diabetic mice were treated with rosuvastatin at 20 mg·kg⁻¹ ·day⁻¹ p.o.for 6 weeks. Isometric force was measured in isolated aortae and renal arteries. Protein expressions including angiotensin II type 1 receptor (AT₁R), NOX4, p22(phox) , p67(phox) , Rac-1, nitrotyrosine, phospho-ERK1/2 and phospho-p38 were determined by Western blotting, while reactive oxygen species (ROS) accumulation in the vascular wall was evaluated by dihydroethidium fluorescence and lucigenin assay.

KEY RESULTS

Rosuvastatin treatment of db/db mice reversed the impaired ACh-induced endothelium-dependent dilatations in both renal arteries and aortae and prevented the exaggerated contractions to angiotensin II and phenylephrine in db/db mouse renal arteries and aortae. Rosuvastatin reduced the elevated expressions of AT₁R, p22(phox) and p67(phox) , NOX4, Rac1, nitrotyrosine and phosphorylation of ERK1/2 and p38 MAPK and inhibited ROS production in aortae from db/db mice.

CONCLUSIONS AND IMPLICATIONS

The vasoprotective effects of rosuvastatin are attributed to an increase in NO bioavailability, which is probably achieved by its inhibition of ROS production from the AT₁R-NAD(P)H oxidase cascade.

Does blood pressure variability modulate cardiovascular risk?

Exactly how hypertension causes end organ damage and vascular events is poorly understood. Yet the concept that underlying "usual" blood pressure (BP) accounts for all BP-related risk of vascular events and for the benefits of BP-lowering drugs has come to underpin clinical guidelines on the diagnosis and treatment of hypertension. This article reviews evidence that variability in BP also predicts risk of stroke and other vascular events independently of mean BP and evidence that drug-class effects on variability in BP explain differences in the effectiveness of BP-lowering drugs in preventing stroke.

Add-on-Statin Extended Release Nicotinic Acid/Laropiprant but Not the Switch to High-Dose Rosuvastatin Lowers Blood Pressure: An Open-Label Randomized Study

Introduction. Nicotinic acid (NA) and statins have been associated with reductions in blood pressure (BP). Patients and Methods. We recruited 68 normotensive and hypertensive dyslipidemic patients who were treated with a conventional statin dose and had not achieved lipid targets. Patients were randomized to switch to high-dose rosuvastatin (40 mg/day) or to add-on current statin treatment with extended release (ER) NA/laropiprant (1000/20 mg/day for the first 4 weeks followed by 2000/40 mg/day for the next 8 weeks) for 3 months. Results. Switching to rosuvastatin 40 mg/day was not associated with significant BP alterations. In contrast, the addition of ER-NA/laropiprant to current statin treatment resulted in a 7% reduction of systolic BP (from 134 ± 12 to 125 ± 10 mmHg, P < .001 versus baseline and P = .01 versus rosuvastatin group) and a 5% reduction of diastolic BP (from 81 ± 9 to 77 ± 6 mmHg, P = .009 versus baseline and P = .01 versus rosuvastatin group). These reductions were significant only in the subgroup of hypertensives and were independent of the hypolipidemic effects of ER-NA/laropiprant. Conclusions. Contrary to the switch to high-dose rosuvastatin, the addition of ER-NA/laropiprant to statin treatment was associated with significant reductions in both systolic and diastolic BP.

Rosuvastatin attenuates the elevation in blood pressure induced by overexpression of human C-reactive protein

C-reactive protein (CRP) has been shown to function as an inflammatory factor to induce endothelial dysfunction and hypertension in rats. The anti-inflammatory effects of statins suggest that they may attenuate CRP-induced endothelial dysfunction and hypertension in Sprague-Dawley rats. Male Sprague-Dawley rats were injected with an adeno-associated virus (AAV) to induce overexpression of human CRP (AAV-hCRP) or green fluorescent protein (GFP) control (AAV-GFP). At 2 months after injection, rats were administered rosuvastatin by daily oral gavage (10 mg kg(-1)) for 2 additional months. Rosuvastatin administration attenuated the increased blood pressure and loss of vascular endothelial nitric oxide synthase expression in AAV-hCRP-treated rats, and N-nitro-L-arginine methyl ester blocked its hypotensive effect. Rosuvastatin also activated phosphoinositide 3-kinases/Akt, and inhibited Rho kinase activity in aorta. Rosuvastatin reduced the production of reactive oxygen species through downregulation of nicotinamide adenine dinucleotide phosphate oxidase subunits, p22 phox and gp91 phox, and upregulation of superoxide dismutase 1 expression. Rosuvastatin attenuated the increase in blood pressure in AAV-hCRP-treated rats through endothelial protection and antioxidant effects. Our data reveals a novel mechanism through which statins may lower blood pressure.

Pharmacological and non-pharmacological interventions to influence adipose tissue function

Obesity is associated with metabolic derangements such as insulin resistance, inflammation and hypercoagulobility which can all be understood as consequences of adipose tissue dysfunction. The potential role for adipose tissue derived cytokines and adipokines in the development of vascular disease and diabetes may produce a clinical need to influence adipose tissue function. Various pharmacological and non-pharmacological interventions affect plasma cytokine and adipokine levels. The effects of these interventions depend on weight loss per se, changes in fat distribution without weight loss and/or direct effects on adipose tissue inflammation.

Weight loss, as a result of diet, pharmacology and surgery, positively influences plasma adipokines and systemic inflammation. Several classes of drugs influence systemic inflammation directly through their anti-inflammatory actions. PPAR-γ agonism positively influences adipose tissue inflammation in several classes of intervention such as the thiazolidinediones and perhaps salicylates, CB1-antagonists and angiotensin II receptor blockers. Furthermore, within drug classes there are differential effects of individual pharmacologic agents on adipose tissue function.

It can be concluded that several commonly used pharmacological and non-pharmacological interventions have unintended influences on adipose tissue function. Improving adipose tissue function may contribute to reducing the risk of vascular diseases and the development of type 2 diabetes.

Pleiotropic effects of statins. - Basic research and clinical perspectives -

Statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, which are widely used to lower serum cholesterol levels in the primary and secondary prevention of cardiovascular disease. Recent experimental and clinical evidence suggests that the beneficial effects of statins may extend beyond their cholesterol-lowering effects, to include so-called pleiotropic effects. These cholesterol-independent effects include improving endothelial function, attenuating vascular and myocardial remodeling, inhibiting vascular inflammation and oxidation, and stabilizing atherosclerotic plaques. The mechanism underlying some of these pleiotropic effects is the inhibition of isoprenoid synthesis by statins, which leads to the inhibition of intracellular signaling molecules Rho, Rac and Cdc42. In particular, inhibition of Rho and one of its downstream targets, Rho kinase, may be a predominant mechanism contributing to the pleiotropic effects of statins. The aim of the present review is to provide an update on the non-cholesterol-dependent statin effects in the cardiovascular system and highlight some of the recent findings from bench to bedside to support the concept of statin pleiotropy.

Limitations of the usual blood-pressure hypothesis and importance of variability, instability, and episodic hypertension

Although hypertension is the most prevalent treatable vascular risk factor, how it causes end-organ damage and vascular events is poorly understood. Yet, a widespread belief exists that underlying usual blood pressure can alone account for all blood-pressure-related risk of vascular events and for the benefits of antihypertensive drugs, and this notion has come to underpin all major clinical guidelines on diagnosis and treatment of hypertension. Other potentially informative measures, such as variability in clinic blood pressure or maximum blood pressure reached, have been neglected, and effects of antihypertensive drugs on such measures are largely unknown. Clinical guidelines recommend that episodic hypertension is not treated, and the potential risks of residual variability in blood pressure in treated hypertensive patients have been ignored. This Review discusses shortcomings of the usual blood-pressure hypothesis, provides background to accompanying reports on the importance of blood-pressure variability in prediction of risk of vascular events and in accounting for benefits of antihypertensive drugs, and draws attention to clinical implications and directions for future research.

The vicious circle between oxidative stress and inflammation in atherosclerosis

The initial event in atherogenesis is the increased transcytosis of low density lipoprotein, and its subsequent deposition, retention and modification in the subendothelium. It is followed by the infiltration of activated inflammatory cells from the coronary circulation into the arterial wall. There they secrete reactive oxygen species (ROS) and produce oxidized lipoproteins capable of inducing endothelial cell apoptosis, and thereby plaque erosion. Activated T lymphocytes, macrophages and mast cells, accumulate in the eroded plaque where they secrete a variety of proteases capable of inducing degradation of extracellular proteins, thereby rendering the plaques more prone to rupture. This review summarizes the recent advancements in the understanding of the roles of ROS and oxidized lipoproteins in the activation of inflammatory cells and inducing signalling pathways related to cell death and apoptosis. In addition, it presents evidence that this vicious circle between oxidative stress and inflammation does not only occur in the diseased arterial wall, but also in adipose tissues. There, oxidative stress and inflammation impair adipocyte maturation resulting in defective insulin action and adipocytokine signalling. The latter is associated with increased infiltration of inflammatory cells, loss of anti-oxidant protection and cell death in the arterial wall.

The vicious circle between oxidative stress and inflammation in atherosclerosis

The initial event in atherogenesis is the increased transcytosis of low density lipoprotein, and its subsequent deposition, retention and modification in the subendothelium. It is followed by the infiltration of activated inflammatory cells from the coronary circulation into the arterial wall. There they secrete reactive oxygen species (ROS) and produce oxidized lipoproteins capable of inducing endothelial cell apoptosis, and thereby plaque erosion. Activated T lymphocytes, macrophages and mast cells, accumulate in the eroded plaque where they secrete a variety of proteases capable of inducing degradation of extracellular proteins, thereby rendering the plaques more prone to rupture. This review summarizes the recent advancements in the understanding of the roles of ROS and oxidized lipoproteins in the activation of inflammatory cells and inducing signalling pathways related to cell death and apoptosis. In addition, it presents evidence that this vicious circle between oxidative stress and inflammation does not only occur in the diseased arterial wall, but also in adipose tissues. There, oxidative stress and inflammation impair adipocyte maturation resulting in defective insulin action and adipocytokine signalling. The latter is associated with increased infiltration of inflammatory cells, loss of anti-oxidant protection and cell death in the arterial wall.

Role and significance of statins in the treatment of hypertensive patients

BACKGROUND

Statins are the first-line drug therapy in the treatment of hypercholesterolemia. The beneficial clinical impact of statins on the cardiovascular system results not only from their lipid-lowering action but also from other effects. Recently, it has been suggested that statins can reduce blood pressure, especially in hypertensive patients.

AIM

The role of the hypotensive action of statins and other mechanisms which reduce cardiovascular risk in hypertensive patients are discussed in this review.

METHODS

Electronic databases searched were [MEDLINE (1966 - February 2009), EMBASE and SCOPUS (1965 - February 2009), DARE (1966 -- February 2009)]. Additionally, abstracts from national and international cardiovascular meetings were studied to identify unpublished studies. The main data search terms were: blood pressure, hypertension, hypercholesterolemia and statins.

FINDINGS

At present, it is difficult to unequivocally assess the impact of statins on blood pressure. However, according to most authors, the impact of statins on the decrease in BP is slight, but significant, especially among patients with hypertension.

Update on statin-mediated anti-inflammatory activities in atherosclerosis

Anti-inflammatory activities of statins in atherosclerosis have been well documented by both basic research and clinical studies. Statins have been introduced in the 1980s as 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors to block cholesterol synthesis and lower cholesterol serum levels. In the last three decades, statins have been shown to possess several anti-inflammatory and antioxidant activities resulting in the beneficial reduction of atherosclerotic processes and cardiovascular risk in both humans and animal models. Inflammatory intracellular pathways involving kinase phosphorylation and protein prenylation are modulated by statins. The same intracellular mechanisms might also cause statin-induced myotoxicity. In the present review, we will update evidence on statin-mediated regulation of inflammatory pathways in atherogenesis.

Oxidized LDL and the metabolic syndrome

The metabolic syndrome is a common and complex disorder combining obesity, dyslipidemia, hypertension and insulin resistance. It is associated with a high cardiovascular risk that can only partially be explained by its components. There is evidence that low-grade inflammation and high oxidative stress add to this risk. Oxidized LDL, a marker of lipoprotein-associated oxidative stress, is an emerging cardiovascular risk factor. In this review, we demonstrate that the metabolic syndrome exacerbates oxidized LDL in a feedback loop. We introduce molecular mechanisms underlying this loop. Finally, we demonstrate that weight loss and statin treatment lower metabolic syndrome factors associated with a reduction of oxidized LDL. The current data warrant further investigation into the role of lifestyle and therapeutic interventions that inhibit tissue-associated oxidation of LDL in the prevention of the metabolic syndrome.

An overview of the extra-lipid effects of rosuvastatin

Statins, in addition to their beneficial lipid modulation effects, exert a variety of several so-called "pleiotropic" actions that may result in clinical benefits. Rosuvastatin, the last agent of the class to be introduced, has proved remarkably potent in reducing low-density lipoprotein cholesterol levels. At present, no large-scale primary or secondary prevention clinical trials document either its long-term safety or its effectiveness in preventing cardiovascular events. A substantial number of experimental and clinical studies have indicate favorable effects of rosuvastatin on endothelial function, oxidized low-density lipoprotein, inflammation, plaque stability, vascular remodeling, hemostasis, cardiac muscle, and components of the nervous system. Available data regarding the effects of rosuvastatin on renal function and urine protein excretion do not seem to raise any safety concerns. Whether the established "pleiotropy" and/or lipid-lowering efficacy of rosuvastatin may translate into reduced morbidity and mortality remains to be shown in ongoing clinical outcome trials.