Simvastatin prevents cardiac hypertrophy in vitro and in vivo via JAK/STAT pathway

Simvastatin Significantly Reduced Alcohol-Induced Cardiac Damage in Adolescent Mice

Alcohol abuse by adolescents is becoming a serious health concern as they often progress to becoming alcoholics later in life which may lead to heart problems. Chronic alcohol use alters the cardiac function and structure, such as haemodynamic changes, weakening and loss of cardiomyocytes, myocardial fibrosis, and inflammation. Simvastatin is a commonly used drug for the treatment and management of various cardiovascular problems but information on its protective effects against alcohol-induced cardiomyocyte hypertrophy, fibrosis, and inflammation is lacking in the literature. Four-week-old male (n = 5) and female (n = 5) C57BL/6 J mice were assigned to each experimental group: (I) NT-no administration of alcohol or Simvastatin; (II) ALC-2.5 g/Kg/day of 20% alcohol via intraperitoneal injection (i.p.); (III) SIM-5 mg/Kg/day of Simvastatin via oral gavage; (iv) ALC + SIM5-5 mg/Kg/day of Simvastatin via oral gavage followed by 2.5 g/Kg/day of 20% alcohol via i.p.; and (v) ALC + SIM15-15 mg/Kg/day Simvastatin via oral gavage followed by 2.5 g/Kg/day of 20% alcohol via i.p. After the 28-day treatment period, the heart was removed and processed for H&E, Masson's trichrome, or TNF-α immunolabelling. The area and diameter of cardiomyocytes were measured on the H&E-stained sections. The distribution of collagen or TNF-α expression was quantified using the deconvolution tool of ImageJ software. The results confirmed alcohol-induced toxicity on the cardiomyocytes and Simvastatin reduced alcohol-induced cardiomyocyte hypertrophy, fibrosis, and inflammation in both sexes. This study demonstrated that Simvastatin, an FDA approved and easily accessible drug, may be beneficial in lowering the prevalence of alcohol-induced cardiovascular diseases (especially in adolescents) which will have a huge financial implication on health systems worldwide.

Effect and mechanism of HMG-CoA reductase inhibitor on the improvement of elderly essential hypertension-induced vascular endothelial function impairment based on the JAK/STAT pathway

OBJECTIVE

Our research was designed to figure out the influence and mechanism of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor on the improvement of elderly essential hypertension-induced vascular endothelial function impairment based on the JAK/STAT pathway.

METHODS

Eighty-six elderly patients with essential hypertension were randomized into a control group (oral Amlodipine Besylate Tablets) and an observation group (oral Amlodipine Besylate Tablets + HMG-CoA reductase inhibitor atorvastatin calcium). Patients in both groups were treated with the drug for 12 weeks. Blood pressure, serum levels of inflammatory factors, and vascular endothelial function indicators, and levels of blood lipids were measured. The modeled rats were treated with atorvastatin calcium and a JAK/STAT pathway inhibitor (AG490), and the levels of cardiac function-related indices, left ventricular mass index, lipid levels, serum inflammatory factors and vascular endothelial function-related indices were detected in each group.

RESULTS

HMG-CoA reductase inhibitor improved blood pressure levels, lipid levels, serum inflammatory factor levels and cardiac function in elderly patients with essential hypertension. Both HMG-CoA reductase inhibitor and AG490 improved blood pressure levels, lipid levels, serum inflammatory factor levels and cardiac function in SHR rats. Both HMG-CoA reductase inhibitor and AG490 decreased p-JAK2/JAK2 and p-STAT3/STAT3 expression levels.

CONCLUSION

Our study demonstrates that HMG-CoA reductase inhibitor improves elderly essential hypertension-induced vascular endothelial function impairment by blocking the JAK/STAT pathway.

Simvastatin-loaded nano-niosomes efficiently downregulates the MAPK-NF-κB pathway during the acute phase of myocardial ischemia-reperfusion injury

BACKGROUND

Simvastatin can potentially mitigate acute inflammatory phase of myocardial ischemia-reperfusion injury. However, these effects negatively influenced by its poor bioavailability, low water solubility and high metabolism. Here, we investigated the effects of SIM-loaded nano-niosomes on a rat model of MI/R injury to find a drug delivery method to tackle the barriers.

METHODS

Nano-niosomes' characteristics were identified using dynamic light scattering and transmission electron microscopy. Fifty male Wistar rats were divided into five groups: Sham; MI/R; MI/R + nano-niosome; MI/R + SIM; MI/R + SIM-loaded nano-niosomes. Left anterior descending artery was ligated for 45 min, and 3 mg/kg SIM, nano-niosomes, or SIM-loaded nano-niosomes was intramyocardially injected ten min before the onset of reperfusion. ELISA assay was used to assess cardiac injury markers (cTnI, CK-MB) and inflammatory cytokines (TNF-α, IL-6, TGF-β, MPC-1). Expression level of MAPK-NF-κB and histopathological changes were evaluated by western blot and hematoxylin & eosin staining, respectively.

RESULTS

the size of nano-niosome was 137 nm, reached to 163 nm when simvastatin was loaded. To achieve optimized niosomes span 80, a drug/cholesterol ratio of 0.4 and seven min of sonication time was applied. Optimized entrapment efficiency of SIM-loaded nano-niosomes was 98.21%. Inflammatory cytokines and the expression level of MAPK and NF-κB were reduced in rats receiving SIM-loaded nano-niosomes compared to MI/R + SIM and MI/R + SIM-loaded nano-niosomes.

CONCLUSION

Our results showed that SIM-loaded nano-niosomes could act more efficiently than SIM in alleviating the acute inflammatory response of reperfusion injury via downregulating the activation of MAPK-NF-κB.

Simvastatin-loaded nano-niosomes confer cardioprotection against myocardial ischemia/reperfusion injury

Although simvastatin (SIM) has been proven to be a powerful agent against myocardial ischemia/reperfusion (MI/R) injury, poor water solubility, short half-life, and low bioavailability have made it futile while using conventional drug delivery system. Hence, this study aims to investigate therapeutic efficacy of SIM-loaded nano-niosomes on MI/R injury. Surface active agent film hydration method was used to synthesize nano-niosomes. The physicochemical properties of nano-niosomes were characterized using dynamic light scattering (DLS) and transmission electron microscopy (TEM). Moreover, niosomes were characterized in entrapment efficiency (EE) and releasing pattern. Male Wistar rats were assigned into five groups (sham, MI/R, SIM, nano-niosomes, and SIM-loaded nano-niosomes). To induce MI/R, left thoracotomy was performed along mid-axillary line. The LAD ligation lasted for 45 min. A single dose (3 mg/kg) of drug formulations was injected into myocardial. Echocardiography was performed to evaluate cardiac function. The expression of the necroptosis markers was evaluated using western blot assay. Particle size of only nano-niosomes was about 137 nm, whereas a shift to 163 nm was observed in nano-niosomes containing SIM. Optimized niosomes were achieved by span 80, drug to cholesterol ratio of 0.4 with 7-min sonication time. EE of optimized nano-niosomes containing SIM was 98.21%. The effects of nano-niosomes containing on improving cardiac function and inhibiting necroptosis pathway was more efficient than the SIM group. Our findings have suggested that nano-niosomes can be applied as a notable drug delivery method to augment stability, bioavailability, and therapeutic efficacy of SIM, when it used against myocardial I/R injury.

Hydrogen-rich saline mitigates pressure overload-induced cardiac hypertrophy and atrial fibrillation in rats via the JAK-STAT signalling pathway

Objective

To investigate if hydrogen-rich saline (HRS), which has been shown to have antioxidant and anti-inflammatory properties, could mitigate cardiac remodelling and reduce the incidence of atrial fibrillation (AF) in the rat model of cardiac hypertrophy.

Methods

Pressure overload was induced in rats by abdominal aortic constriction (AAC). The animals were separated into four groups: sham; AAC group; AAC plus low dose HRS (LHRS); AAC plus high dose HRS (HHRS). The sham and AAC groups received normal saline intraperitoneally and the LHRS and HHRS groups received 3 or 6 ml/kg HRS daily for six weeks, respectively. In vitro research was also performed using cardiotrophin-1 (CT-1)-induced hypertrophy of cultured neonatal rat cardiomyocytes.

Results

Cardiac hypertrophy was successfully induced by AAC and low and high dose HRS mitigated the pressure overload as shown by lower heart and atrial weights in these treatment groups. AF incidence and duration of the HRS groups were also significantly lower in the HRS groups compared with the AAC group. Atrial fibrosis was also reduced in the HRS groups and the JAK-STAT signalling pathway was down-regulated. In vitro experiments showed that hydrogen-rich medium mitigated the CT-1-induced cardiomyocyte hypertrophy with a similar effect as the JAK specific antagonists AG490.

Conclusions

HRS was found to mitigate cardiac hypertrophy induced by pressure overload in rats and reduce atrial fibrosis and AF which was possibly achieved via inhibition of the JAK-STAT signalling pathway.

Simvastatin Ameliorates Diabetic Cardiomyopathy by Attenuating Oxidative Stress and Inflammation in Rats

Simvastatin is a lipid-lowering agent used to treat hypercholesterolemia and to reduce the risk of heart disease. This study scrutinized the beneficial effects of simvastatin on experimental diabetic cardiomyopathy (DCM), pointing to the role of hyperglycemia-induced oxidative stress and inflammation. Diabetes was induced by intraperitoneal injection of streptozotocin and both control and diabetic rats received simvastatin for 90 days. Diabetic rats showed significant cardiac hypertrophy, body weight loss, hyperglycemia, and hyperlipidemia. Serum creatine kinase MB (CK-MB) and troponin I showed a significant increase in diabetic rats. Simvastatin significantly improved body weight, attenuated hyperglycemia and hyperlipidemia, and ameliorated CK-MB and troponin I. Simvastatin prevented histological alterations and deposition of collagen in the heart of diabetic animals. Lipid peroxidation and nitric oxide were increased in the heart of diabetic rats whereas antioxidant defenses were decreased. These alterations were significantly reversed by simvastatin. In addition, simvastatin decreased serum inflammatory mediators and expression of NF-κB in the diabetic heart. Cardiac caspase-3 was increased in the diabetic heart and decreased following treatment with simvastatin. In conclusion, our results suggest that simvastatin alleviates DCM by attenuating hyperglycemia/hyperlipidemia-induced oxidative stress, inflammation, and apoptosis.

Stachydrine ameliorates isoproterenol-induced cardiac hypertrophy and fibrosis by suppressing inflammation and oxidative stress through inhibiting NF-κB and JAK/STAT signaling pathways in rats

Cardiac hypertrophy (CH), as one of the major causes of morbidity and mortality in the world, has become an independent and predictive risk factor for adverse cardiovascular events. However, progress in treatment remains sluggish in recent years. Therefore, compounds derived from non-toxic nature plants are urgently needed. Stachydrine (STA), which is isolated from Leonurus, has various activities, including resistance to cardiovascular disease, but little is known about its effect on CH or the mechanisms. We herein investigated the effect of STA on isoproterenol-induced CH and the underlying mechanisms. Treatment with STA significantly increased the ratios of heart weight/body weight, left ventricle weight/body weight and the cross-sectional areas of cardiomyocytes. In addition, STA significantly decreased the mRNA levels of atrial natriuretic peptide, B-type natriuretic peptide and β-myosin heavy chain. Furthermore, isoproterenol-induced fibrosis in rats receiving STA was significant attenuated, as evidenced by decreased ratio of fibrotic area/total area and decreased mRNA levels of collagens I and III. Given down-regulation of interleukin-6, tumor necrosis factor-α, interferon-γ (IFN-γ) and IFN-1β, treatment with STA significantly reversed the expressions of pro-inflammatory induced by isoproterenol. Moreover, STA attenuated the oxidative stress level in serum of isoproterenol-induced CH rats, as shown by increased activity of superoxide dismutase and decreased malondialdehyde level. STA inhibited the expressions of phosphorylated IκBα, NF-κB p65, JAK2 and STAT3 in vivo. Thus, both NF-κB and JAK/STAT signalings played essential roles in mediating the anti-CH effect of STA. Collectively, STA has a potent protective effect on isoproterenol-induced CH, with therapeutic implication for CH.

JAK2/STAT3 Pathway Mediates Protection of Metallothionein Against Doxorubicin-Induced Cytotoxicity in Mouse Cardiomyocytes

Doxorubicin (Dox) is one of the most important anticancer agents; however, its clinical application is limited by its severe cardiotoxicity. In our previous study, we found that the gene expression levels of the Janus-activated kinase/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway were different between MT(-/-) cardiomyocytes and MT(+/+) cardiomyocytes when they were treated with Dox. Thus, this study was intended to investigate the role of JAK2/STAT3 pathway in metallothionein (MT) protection of Dox-induced cardiotoxicity. Tyrphostin AG490 (α-cyano-(3,4-dihydroxy)-N-benzylcinnamide) is a synthetic protein tyrosine kinase inhibitor which at first has been considered as a specific JAK2 inhibitor and can inhibit the JAK2/STAT3 signaling pathway. In the present study, AG490 was used to assess the role of JAK2/STAT3 in MT protection against Dox-induced cardiotoxicity. The AG490 can attenuate the MT protection by increasing lactate dehydrogenase and the number of apoptotic cells. Interestingly, pretreated with AG490, MT(-/-) cardiomyocytes were more sensitive than MT(+/+) to Dox-induced cytotoxicity as measured by reactive oxygen species generation, lipid peroxidation, and protein carbonylation. Metallothionein 1 and MT-2 messenger RNA were upregulated by Dox, and AG490 decreased the protein expression of MT-1 and MT-2. After Dox treatment, the protein expression of p-Jak2 and p-Stat3 levels was significantly increased in MT(+/+) cardiomyocytes, suggesting that the JAK2/STAT3 pathway was partially involved in MT protection against Dox-induced cardiotoxicity.

Simvastatin prevents isoproterenol-induced cardiac hypertrophy through modulation of the JAK/STAT pathway

Simvastatin (SIM) is a lipid-soluble inhibitor of hydroxy-3-methylglutaryl coenzyme A reductase with multiple reported therapeutic benefits. The present study was designed to investigate the effect of pretreatment with SIM on isoproterenol (ISO)-induced cardiac hypertrophy in rats. Twenty-four male albino Wistar rats weighing 180–200 g were divided into four groups. Groups I and III received normal saline while groups II and IV received SIM (10 mg/kg body weight) for 30 days per gavage. In the last 7 days, rats of groups III and IV were administered ISO (5 mg/kg) intraperitoneally to induce cardiac hypertrophy. Administration of ISO induced an increase in heart-to-body weight (HW/BW) ratio, an increase in serum interleukin-6, and elevated systolic and diastolic blood pressure. Serum levels of lipids, cardiovascular risk indices, and cardiac troponin I and creatine phosphokinase-MB showed significant increase in ISO-induced hypertrophic rats. Histopathological examination of heart tissue revealed focal areas of subendocardium degeneration, mononuclear cellular infiltrations, fibrous tissue deposition, and increased thickness of the myocardium of left ventricle. In addition, ISO-administered rats exhibited significant upregulation of cardiac Janus kinase, phosphorylated signal transducer and activator of transcription, and nuclear factor-kappa B. Pretreatment with SIM significantly prevented ISO-induced cardiac hypertrophy, alleviated the altered biochemical parameters, and improved the heart architecture. In conclusion, our study provides evidence that SIM prevented the development of cardiac hypertrophy via modulation of the Janus kinase/signal transducer and activator of transcription-signaling pathway in the heart of ISO-administered animals.

In vitro effects of exercise on the heart

Pathologic and physiologic factors acting on the heart can produce consistent pressure changes, volume overload, or increased cardiac output. These changes may then lead to cardiac remodeling, ultimately resulting in cardiac hypertrophy. Exercise can also induce hypertrophy, primarily physiologic in nature. To determine the mechanisms responsible for each type of remodeling, it is important to examine the heart at the functional unit, the cardiomyocyte. Tests of individual cardiomyocyte function in vitro provide a deeper understanding of the changes occurring within the heart during hypertrophy. Examination of cardiomyocyte function during exercise primarily follows one of two pathways: the addition of hypertrophic inducing agents in vitro to normal cardiomyocytes, or the use of trained animal models and isolating cells following the development of hypertrophy in vivo. Due to the short lifespan of adult cardiomyocytes, a proportionately scant amount of research exists involving the direct stimulation of cells in vitro to induce hypertrophy. These attempts provide the only current evidence, as it is difficult to gather extensive data demonstrating cell growth as a result of in vitro physical stimulation. Researchers have created ways to combine skeletal myocytes with cardiomyocytes to produce functional muscle cells used to repair pathologic heart tissue, but continue to struggle with the short lifespan of these cells. While there have been promising findings regarding the mechanisms that surround cardiac hypertrophy in vitro, the translation of in vitro findings to in vivo function is not consistent. Therefore, the focus of this review is to highlight recent studies that have investigated the effect of exercise on the heart, both in vitro and in vivo.

Effect of ligustilide on Ang II-induced hypertrophy in cardiomyocytes and the potential mechanisms

The aim of the present study was to investigate the effect of ligustilide (LIG) on angiotensin II (Ang II)-induced hypertrophy in neonatal rat myocardial cells and the expression levels of p53, Bcl-2 and Bax. Myocardial cells were isolated and purified from the ventricles of neonate Sprague-Dawley rats (age, 1–3 days) using a differential adhesion method. The cells were then were stimulated by Ang II and LIG for 1–3 days, following which the cell surface area, intracellular protein concentration, rate of apoptosis and the expression levels of p53, Bcl-2 and Bax were determined. Following stimulation with Ang II, the cell surface area of the neonatal rat myocardial cells increased significantly and the cell morphology was distorted. LIG was shown to significantly suppress the Ang II-induced hypertrophy of neonatal rat myocardial cells in a dose-dependent manner. In addition, administration of LIG restored the expression levels of p53, Bcl-2 and Bax. Therefore, LIG can prevent the hypertrophy of cardiomyocytes induced by Ang II, which may be associated with the inhibitory effect that LIG exhibits on cardiomyocyte apoptosis.

Involvement of peptidyl-prolyl isomerase Pin1 in the inhibitory effect of fluvastatin on endothelin-1-induced cardiomyocyte hypertrophy

AIMS

Cardiac hypertrophy is elicited by endothelin (ET)-1 as well as other neurohumoral factors, hemodynamic overload, and oxidative stress; HMG-CoA reductase inhibitors (statins) were shown to inhibit cardiac hypertrophy partly via the anti-oxidative stress. One of their common intracellular pathways is the phosphorylation cascade of MEK signaling. Pin1 specifically isomerizes the phosphorylated protein with Ser/Thr-Pro bonds and regulates their activity through conformational changes. There is no report whether the Pin1 activation contributes to ET-1-induced cardiomyocyte hypertrophy and whether the Pin1 inactivation contributes to the inhibitory effect of statins. The aim of this study was to reveal these questions.

MAIN METHODS

We assessed neonatal rat cardiomyocyte hypertrophy using ET-1 and fluvastatin by the cell surface area, ANP mRNA expression, JNK and c-Jun phosphorylation, and [(3)H]-leucine incorporation.

KEY FINDINGS

Fluvastatin inhibited ET-1-induced increase in the cell surface area, ANP expression, and [(3)H]-leucine incorporation; and it suppressed the signaling cascade from JNK to c-Jun. The phosphorylated Pin1 level, an inactive form, was decreased by ET-1; however, it reached basal level by fluvastatin. Furthermore, Pin1 overexpression clearly elicited cardiomyocyte hypertrophy, which was inhibited by fluvastatin.

SIGNIFICANCE

This is the first report that ET-1-induced cardiomyocyte hypertrophy is mediated through the Pin1 activation and that the inhibitory effect of fluvastatin on cardiomyocyte hypertrophy would partly be attributed to the suppression of the Pin1 function. This study firstly suggests that Pin1 determines the size of hypertrophied cardiomyocyte by regulating the activity of phosphorylated molecules and that statins exert their pleiotropic effects partly via Pin1 inactivation.

Targeting the mevalonate cascade as a new therapeutic approach in heart disease, cancer and pulmonary disease

The cholesterol biosynthesis pathway, also known as the mevalonate (MVA) pathway, is an essential cellular pathway that is involved in diverse cell functions. The enzyme 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase (HMGCR) is the rate-limiting step in cholesterol biosynthesis and catalyzes the conversion of HMG-CoA to MVA. Given its role in cholesterol and isoprenoid biosynthesis, the regulation of HMGCR has been intensely investigated. Because all cells require a steady supply of MVA, both the sterol (i.e. cholesterol) and non-sterol (i.e. isoprenoid) products of MVA metabolism exert coordinated feedback regulation on HMGCR through different mechanisms. The proper functioning of HMGCR as the proximal enzyme in the MVA pathway is essential under both normal physiologic conditions and in many diseases given its role in cell cycle pathways and cell proliferation, cholesterol biosynthesis and metabolism, cell cytoskeletal dynamics and stability, cell membrane structure and fluidity, mitochondrial function, proliferation, and cell fate. The blockbuster statin drugs ('statins') directly bind to and inhibit HMGCR, and their use for the past thirty years has revolutionized the treatment of hypercholesterolemia and cardiovascular diseases, in particular coronary heart disease. Initially thought to exert their effects through cholesterol reduction, recent evidence indicates that statins also have pleiotropic immunomodulatory properties independent of cholesterol lowering. In this review we will focus on the therapeutic applications and mechanisms involved in the MVA cascade including Rho GTPase and Rho kinase (ROCK) signaling, statin inhibition of HMGCR, geranylgeranyltransferase (GGTase) inhibition, and farnesyltransferase (FTase) inhibition in cardiovascular disease, pulmonary diseases (e.g. asthma and chronic obstructive pulmonary disease (COPD)), and cancer.

Simvastatin impairs growth hormone-activated signal transducer and activator of transcription (STAT) signaling pathway in UMR-106 osteosarcoma cells

Recent studies have demonstrated that statins reduce cell viability and induce apoptosis in various types of cancer cells. The molecular mechanisms underlying these effects are poorly understood. The JAK/STAT pathway plays an important role in the regulation of proliferation and apoptosis in many tissues, and its deregulation is believed to be involved in tumorigenesis and cancer. The physiological activation of STAT proteins by GH is rapid but transient in nature and its inactivation is regulated mainly by the expression of SOCS proteins. UMR-106 osteosarcoma cells express a GH-responsive JAK2/STAT5 signaling pathway, providing an experimental model to study the influence of statins on this system. In this study we investigated the actions of simvastatin on cell proliferation, migration, and invasion on UMR-106 cells and examined whether alterations in GH-stimulated JAK/STAT/SOCS signaling may be observed. Results showed that treatment of osteosarcoma cells with simvastatin at 3 to 10 µM doses decreases cell proliferation, migration, and invasion in a time- and dose-dependent manner. At the molecular level, although the mechanisms used by simvastatin are not entirely clear, the effect of the statin on the reduction of JAK2 and STAT5 phosphorylation levels may partially explain the decrease in the GH-stimulated STAT5 transcriptional activity. This effect correlated with a time- and dose-dependent increase of SOCS-3 expression levels in cells treated with simvastatin, a regulatory role that has not been previously described. Furthermore, the finding that simvastatin is capable of inducing SOCS-3 and CIS genes expression shows the potential of the JAK/STAT pathway as a therapeutic target, reinforcing the efficacy of simvastatin as chemotherapeutic drug for the treatment of osteosarcoma.

Statins in heart failure--With preserved and reduced ejection fraction. An update

HMG-CoA reductase inhibitors or statins beyond their lipid lowering properties and mevalonate inhibition exert also their actions through a multiplicity of mechanisms. In heart failure (HF) the inhibition of isoprenoid intermediates and small GTPases, which control cellular function such as cell shape, secretion and proliferation, is of clinical significance. Statins share also the peroxisome proliferator-activated receptor pathway and inactivate extracellular-signal-regulated kinase phosphorylation suppressing inflammatory cascade. By down-regulating Rho/Rho kinase signaling pathways, statins increase the stability of eNOS mRNA and induce activation of eNOS through phosphatidylinositol 3-kinase/Akt/eNOS pathway restoring endothelial function. Statins change also myocardial action potential plateau by modulation of Kv1.5 and Kv4.3 channel activity and inhibit sympathetic nerve activity suppressing arrhythmogenesis. Less documented evidence proposes also that statins have anti-hypertrophic effects - through p21ras/mitogen activated protein kinase pathway - which modulate synthesis of matrix metalloproteinases and procollagen 1 expression affecting interstitial fibrosis and diastolic dysfunction. Clinical studies have partly confirmed the experimental findings and despite current guidelines new evidence supports the notion that statins can be beneficial in some cases of HF. In subjects with diastolic HF, moderately impaired systolic function, low b-type natriuretic peptide levels, exacerbated inflammatory response and mild interstitial fibrosis evidence supports that statins can favorably affect the outcome. Under the lights of this evidence in this review article we discuss the current knowledge on the mechanisms of statins' actions and we link current experimental and clinical data to further understand the possible impact of statins' treatment on HF syndrome.

Cardiotrophin-1 in hypertensive heart disease

Hypertensive heart disease, here defined by the presence of pathologic left ventricular hypertrophy in the absence of a cause other than arterial hypertension, is characterized by complex changes in myocardial structure including enhanced cardiomyocyte growth and non-cardiomyocyte alterations that induce the remodeling of the myocardium, and ultimately, deteriorate left ventricular function and facilitate the development of heart failure. It is now accepted that a number of pathological processes mediated by mechanical, neurohormonal, and cytokine routes acting on the cardiomyocyte and the non-cardiomyocyte compartments are responsible for myocardial remodeling in the context of arterial hypertension. For instance, cardiotrophin-1 is a cytokine member of the interleukin-6 superfamily, produced by cardiomyocytes and non-cardiomyocytes in situations of biomechanical stress that once secreted interacts with its receptor, the heterodimer formed by gp130 and gp90 (also known as leukemia inhibitory factor receptor beta), activating different signaling pathways leading to cardiomyocyte hypertrophy, as well as myocardial fibrosis. Beyond its potential mechanistic contribution to the development of hypertensive heart disease, cardiotrophin-1 offers the opportunity for a new translational approach to this condition. In fact, recent evidence suggests that cardiotrophin-1 may serve as both a biomarker of left ventricular hypertrophy and dysfunction in hypertensive patients, and a potential target for therapies aimed to prevent and treat hypertensive heart disease beyond blood pressure control.

Simvastatin modulates remodeling of Kv4.3 expression in rat hypertrophied cardiomyocytes

Objectives: Hypertrophy has been shown to be associated with arrhythmias which can be caused by abnormal remodeling of the Kv4-family of transient potassium channels. Inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (statins) have recently been shown to exert pleiotropic protective effects in cardiovascular diseases, including anti-arrhythmias. It is hypothesized that remodeling of Kv4.3 occurs in rat hypertrophied cardiomyocytes and is regulated by simvastatin.

Methods: Male Sprague-Dawley rats and neonatal rat ventricular myocytes (NRVMs) underwent abdominal aortic banding (AAB) for 7 weeks and angiotensin II (AngII) treatment, respectively, to induce cardiac hypertrophy. Kv4.3 expression by NRVMs and myocardium (subepicardial and subendocardial) in the left ventricle was measured. The transient outward potassium current (I_to) of NRVMs was recorded using a whole-cell patch-clamp method.

Results: Expression of the Kv4.3 transcript and protein was significantly reduced in myocardium (subepicardial and subendocardial) in the left ventricle and in NRVMs. Simvastatin partially prevented the reduction of Kv4.3 expression in NRVMs and subepicardial myocardium but not in the subendocardial myocardium. Hypertrophied NRVMs exhibited a significant reduction in the I_to current and this effect was partially reversed by simvastatin.

Conclusions: Simvastatin alleviated the reduction of Kv4.3 expression, I_to currents in hypertrophied NRVMs and alleviated the reduced Kv4.3 expression in subepicardial myocardium from the hypertrophied left ventricle. It can be speculated that among the pleiotropic effects of simvastatin, the anti-arrhythmia effect is partly mediated by its effect on Kv4.3.

Statins and myocardial remodelling: cell and molecular pathways

The advent of statins has revolutionised the treatment of patients with raised plasma cholesterol and increased cardiovascular risk. However, the beneficial effects of this class of drugs are far greater than would be expected from lowering of cholesterol alone, and they appear to offer cardiovascular protection at multiple levels, primarily as a result of their pleiotropic activity. Indeed, their favourable effects on the heart seem to be mediated in part through reduced prenylation and subsequent inhibition of small GTPases, particularly those of the Rho family. Such statin-mediated effects are manifested by reduced onset of heart failure and improvements in cardiac dysfunction and remodelling in heart failure patients. Experimental studies have shown that statins mediate their effects on the two major resident cell types of the heart--cardiomyocytes and cardiac fibroblasts--and thus facilitate improvement of adverse remodelling of ischaemic or non-ischaemic aetiology. This review examines evidence for the cellular effects of statins in the heart, and discusses the underlying molecular mechanisms at the level of the cardiomyocyte (hypertrophy, cell death and contractile function) and the cardiac fibroblast (differentiation, proliferation, migration and extracellular matrix synthesis). The prospects for future therapies and ongoing clinical trials are also summarised.

Cardiotrophin-1 in cardiovascular regulation

Cardiotrophin (CT)-1 was discovered by coupling expression cloning with an embryonic stem cell-based model of cardiogenesis. Comparison of similarity in amino acid sequence and conformational structure indicates that CT-1 is a member of the interleukin (IL)-6 type cytokine family that shares the transmembrane signaling protein, glycoprotein (gp) 130 as a receptor. These cytokines mediate overlapping pleiotropic actions on a variety of cell types including cardiac myocytes, hepatocytes, megakaryocytes, osteoclasts, and neuronal cells. CT-lmediates its hypertrophic and cytoprotective properties through the Janus kinase/signal transducers and activators of transcription (JAK/STAT), mitogen-activated protein (MAP) kinase, phosphatidylinositol (PI) 3 kinase, and nuclear factor kappa B (NFkappaB) pathways. CT-1 gene and protein are distributed not only in the heart, but also in the pulmonary, renal, gastrointestinal, cerebral, and muscular tissues. CT-1 could also be synthesized and secreted from vascular endothelial cells and adipocytes. CT-1 has hypertrophic actions on the cardiac myocytes, skeletal muscle cells, and smooth muscle cells as well as cytoprotective actions on the cardiac myocytes, neuronal cells, and hepatocytes. CT-1 is circulating in the body, and its plasma concentration is increased in various cardiovascular and renal diseases such as hypertension, congestive heart failure, myocardial infarction, valvular heart disease, metabolic syndrome, and chronic kidney disease. Treatment with CT-1 is beneficial in experimental animal models of cardiovascular diseases. CT-1 specifically protects the cardiac myocytes from ischemic damage when CT-1 is given not only prior to the ischemia, but also given at the time of reoxygenation. Current evidence suggests that CT-1 plays an important role in the regulation of the cardiovascular system.

Simvastatin prevents ERK activation in myocardial hypertrophy of spontaneously hypertensive rats

BACKGROUND

Statins exert regression of left ventricular hypertrophy independent of their plasma cholesterol-lowering actions. However, the underlying mechanism is not clear.

METHODS

We tested the hypothesis that the extracellular signal-regulated kinases (ERKs) signaling pathway could be a target of simvastatin (SIM) and involved in SIM-induced LVH regression in spontaneously hypertensive rats (SHR). Fourteen 14-week old-SHR males were randomly divided into a SHR SIM group (n = 7) or a SHR control group (n = 7). The SHR SIM group was given SIM 40 mg/kg · d via injection ig, while the SHR control group was routinely given only vehicle (0.5% carboxymethyl cellulose ig). Seven Wistar Kyoto rats served as normal controls.

RESULTS

Ten weeks of treatment with SIM in SHR had no influence on blood pressure. The ratio of left ventricle weight to body weight in the SHR SIM group was decreased significantly compared to that in the SHR control group (p < 0.05). Among the three groups there was no significant difference in total ERK expression (p > 0.05). SIM treatment caused a significant reduction in the expression of phosphorylated-ERK, the kinase activity of ERK, the levels of mitogen-activated protein kinase phosphatase-1 protein and its mRNA (p <0.01 for all).

CONCLUSIONS

The Hydroxymethylglutaryl coenzyme A reductase inhibitor SIM prevents the activation of ERK in SHR to mediate regression of myocardial hypertrophy in SHR.

Simvastatin as a treatment for pulmonary hypertension trial

RATIONALE

In animal models of pulmonary hypertension, simvastatin has been shown to reduce pulmonary artery pressure and induce regression of associated right ventricular (RV) hypertrophy.

OBJECTIVES

To assess the therapeutic value of simvastatin in patients with pulmonary arterial hypertension (PAH).

METHODS

Forty-two patients with PAH were randomized to receive either simvastatin (80 mg/d) or placebo in addition to current care for 6 months, and thereafter offered open-label simvastatin. The primary outcome was change in RV mass, assessed by cardiac magnetic resonance (CMR).

MEASUREMENTS AND MAIN RESULTS

At 6 months, RV mass decreased by 5.2 +/- 11 g in the statin group (P = 0.045) and increased 3.9 +/- 14 g in the placebo group. The treatment effect was -9.1 g (P = 0.028). N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels decreased significantly in the statin group (-75 +/- 167 fmol/ml; P = 0.02) but not the placebo group (49 +/- 224 fmol/ml; P = 0.43; overall treatment effect -124 fmol/ml; P = 0.041). There were no significant changes in other outcome measures (including 6-minute walk test, cardiac index, and circulating cytokines). From 6 to 12 months, both RV mass and NT-proBNP increased toward baseline values in 16 patients on active treatment who continued with simvastatin but remained stable in 18 patients who switched from placebo to simvastatin. Two patients required a reduction in dose but not cessation of simvastatin.

CONCLUSIONS

Simvastatin added to conventional therapy produces a small and transient early reduction in RV mass and NT-proBNP levels in patients with PAH, but this is not sustained over 12 months.