Statins initiated after hypertrophy inhibit oxidative stress and prevent heart failure in rats with aortic stenosis

Lipid lowering in dialysis patients with cardiovascular disease who are awaiting kidney transplantation

Dyslipidemias are highly prevalent in chronic kidney disease, end-stage renal disease, and kidney transplant patients. These dyslipidemias are associated with high cardiovascular risk and mortality. Many clinical trials have shown that statin therapy can significantly reduce adverse cardiovascular events in chronic kidney disease patients and kidney transplant recipients. However, three major trials did not show a benefit of statin therapy in end-stage renal disease patients on dialysis. Major guidelines either recommend against the use of statins in patients on dialysis or provide no recommendations about statin use for this complex patient population. As a result, we suspect many patients on dialysis are not on statins, even if they have known atherosclerotic cardiovascular disease. When these patients receive kidney transplants, the risk of adverse cardiovascular events increases in the peri-operative period. Although there are no randomized clinical trials looking at statin use in these patients, we suggest that statin use be considered in patients with a history of atherosclerotic cardiovascular disease, to potentially minimize peri-operative cardiovascular complications. We also recommend further research to determine whether statin therapy in dialysis patients awaiting kidney transplant is associated with better survival.

Atorvastatin protects cardiomyocytes against OGD/R‑induced apoptosis by inhibiting miR‑199a‑5p

The present study aimed to evaluate the protective effects of atorvastatin against myocardial ischemia/reperfusion (I/R) injury in cardiomyocytes and its underlying mechanisms. The direct cytotoxic effects of oxygen-glucose deprivation/reperfusion (OGD/R) on cardiomyocytes with and without atorvastatin pretreatment were evaluated. The effects of atorvastatin on the expression of glycogen synthase kinase-3β (GSK-3β) and microRNA (miR)-199a-5p were determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analyses. In addition, the expression levels of GSK-3β in cells with miR-199a-5p upregulation and downregulation were detected using RT-qPCR, western blot and immunohistochemical analyses. Pretreatment with atorvastatin significantly improved the recovery of cell viability from OGD/R (P<0.05). In addition, atorvastatin pretreatment significantly increased the expression of GSK-3β at the mRNA and protein levels, and the expression of miR-199a-5p at the mRNA level (all P<0.05). The upregulation and downregulation of miR-199a-5p respectively decreased and increased the expression of GSK-3β at the mRNA and protein levels. These results suggested that atorvastatin provided cardioprotective effects against I/R injury via increasing the expression of GSK-3β through the inhibition of miR-199a-5p.

HDAC2 is required by the physiological concentration of glucocorticoid to inhibit inflammation in cardiac fibroblasts

We previously suggested that endogenous glucocorticoids (GCs) may inhibit myocardial inflammation induced by lipopolysaccharide (LPS) in vivo. However, the possible cellular and molecular mechanisms were poorly understood. In this study, we investigated the role of physiological concentration of GCs in inflammation induced by LPS in cardiac fibroblasts and explored the possible mechanisms. The results showed that hydrocortisone at the dose of 127 ng/mL (equivalent to endogenous basal level of GCs) inhibited LPS (100 ng/mL)-induced productions of TNF-α and IL-1β in cardiac fibroblasts. Xanthine oxidase/xanthine (XO/X) system impaired the anti-inflammatory action of GCs through downregulating HDAC2 activity and expression. Knockdown of HDAC2 restrained the anti-inflammatory effects of physiological level of hydrocortisone, and blunted the ability of XO/X system to downregulate the inhibitory action of physiological level of hydrocortisone on cytokines. These results suggested that HDAC2 was required by the physiological concentration of GC to inhibit inflammatory response. The dysfunction of HDAC2 induced by oxidative stress might be account for GC resistance and chronic inflammatory disorders during the cardiac diseases.

Statin Induced Regression of Cardiomyopathy Trial: A Randomized, Placebo-controlled Double-blind Trial

Background:

Hypertrophic cardiomyopathy (HCM), characterized by a thickened, fibrotic myocardium, remains the most common cause of sudden cardiac death in young adults. Based on animal and clinical data, we hypothesized that atorvastatin would induce left ventricular (LV) mass regression.

Methods:

Statin Induced Regression of Cardiomyopathy Trial (SIRCAT) was a randomized, placebo-controlled study. The primary endpoint was change in LV mass measured by cardiac magnetic resonance imaging 12 months after treatment with once-daily atorvastatin 80 mg or placebo. A key secondary endpoint was diastolic dysfunction measured echocardiographically by transmitral flow velocities. SIRCAT is registered with www.clinicaltrials.gov (NCT00317967).

Results:

Of 222 screened patients, 22 were randomized evenly to atorvastatin and placebo. The mean age was 47 ± 10 years, and 15 (68%) were male. All subjects completed the protocol. At baseline, LV masses were 197 ± 76 g and 205 ± 82 g in the placebo and atorvastatin groups, respectively. After 12 months treatment, the LV masses in the placebo and atorvastatin groups were 196 ± 80 versus 206 ± 92 g (P = 0.80), respectively. Echocardiographic indices were not different in the two groups at baseline. After 12 months, diastolic dysfunction as assessed using transmitral flow velocities E/E', A/A', and peak systolic mitral velocity showed no benefit from atorvastatin.

Conclusions:

In patients with HCM, atorvastatin did not cause LV mass regression or improvements in LV diastolic function.

Survival Benefit of Statins in Hemodialysis Patients Awaiting Renal Transplantation

End-stage renal disease (ESRD) patients have extraordinarily high cardiovascular risk and mortality, yet the benefit of statins in this population remains unclear based on the randomized trials. We investigated the prognostic value of statins in a large, pure cohort of prospectively recruited patients with ESRD awaiting renal transplantation, and being followed up in a dedicated cardiac clinic. We prospectively collected demographic, clinical, laboratory, and pharmacological data on 423 consecutive ESRD patients on hemodialysis awaiting renal transplantation. Survival analysis was performed as a function of statin therapy. The baseline characteristics were as follows: age 57 ± 11 years, males 64%, diabetes mellitus in 68%, known coronary artery disease in 30%, left ventricular (LV) ejection fraction 61 ± 11%. Over a mean follow-up of 2 years, there were 43 deaths. Adjusted for age, gender, hypertension, body mass index, diabetes mellitus, coronary artery disease, smoking, and treatment with angiotensin converting enzyme inhibitor, β blocker, and antiplatelet medications, statin use was a predictor of lower mortality (hazard ratio 0.30, 95% confidence interval 0.11-0.79, p = 0.01). This beneficial effect of statin was supported by propensity score analysis (p = 0.02) and was consistent across all clinical subgroups. The benefit of statins seemed to be greater in those with LV hypertrophy and smoking. Statin therapy in hemodialysis patients awaiting renal transplant is independently associated with better survival supporting its use in this high-risk population.

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.

Effects of rosuvastatin on serum asymmetric dimethylarginine levels and atrial structural remodeling in atrial fibrillation dogs

BACKGROUND

Circulating asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, is increased in atrial fibrillation (AF). The purpose of this study was to investigate the effects of rosuvastatin on serum ADMA levels and atrial structural remodeling in AF dogs induced by chronic rapid atrial pacing.

METHODS

Twenty dogs were randomly divided into the sham-operated (n=6), control (n=7), or rosuvastatin (n=7) groups. Sustained AF was induced by rapid pacing of the right atrium at 400 beats per minute for 6 weeks. Rosuvastatin was administered orally (1 mg/kg d) for 3 days before rapid pacing and was continued for 6 weeks. Transthoracic and transesophageal echocardiography were performed to detect left atrial structure and function. Serum levels of nitric oxide and ADMA were measured. Interstitial fibrosis and cardiomyocyte apoptosis in the atria were also identified.

RESULTS

After 6 weeks, compared with the control group, dramatic smaller left atrium and left atrial appendage volumes and higher atrial contractile function were observed in the rosuvastatin group. Serum nitric oxide concentration was increased, whereas ADMA was decreased in the rosuvastatin group compared with the control group. The percentages of interstitial fibrosis and atrial apoptosis in the control group were significantly higher than those in the sham-operated group, and rosuvastatin attenuated these changes induced by atrial rapid pacing.

CONCLUSION

A short course of rosuvastatin treatment decreased apoptosis and prevented atrial structural remodeling in association with a decrease in ADMA levels in AF dogs.

Atorvastatin ameliorates tissue damage of obstructed ureter in rats

AIMS

To investigate the effects of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor on the tissue damage and fibrosis of obstructed ureters, 80 rats were studied.

MAIN METHODS

Atorvastatin, a HMG-CoA reductase inhibitor, was administered to 40 rats at the dose of 20 mg/kg per day 1day before unilateral ligation of ureters and every day thereafter. The other rats served as controls. Eight rats from each group were sacrificed for examination on days 7, 14, 21, 28 and 42 after ligation, respectively. The expressions of transforming growth factor-β1 (TGF-β1), Interleukine-1β (IL-1β), Interleukine-6 (IL-6), tumor necrosis factor-alpha (TNF-α), proliferation cell nuclear antigen (PCNA), and the apoptotic cells in the ureteric smooth muscle were examined.

KEY FINDINGS

Hydroureter and fibrosis of the muscle layer became progressively aggravated in the ligated ureters of the atorvastatin-treated group and control group. The severities of hydroureter and muscle layer fibrosis in the ligated ureters of the treated group were significantly less than in the control group. The atorvastatin administration also decreased the expression of TGF-β1, IL-1β, IL-6, TNF-α, PCNA and the labeling index of apoptotic cells in the smooth muscle layer of ligated ureters in the treated group.

SIGNIFICANCE

We concluded that atorvastatin might ameliorate the tissue damage of obstructed ureters, at least partially, via the inhibition on TGF-β1) expression and by diminishing the effects of pro-inflammatory cytokines.

ROS signalling of inflammatory cytokines during Trypanosoma cruzi infection

Inflammation is a host defence activated by exogenous (e.g. pathogen-derived, pollutants) or endogenous (e.g. reactive oxygen species-ROS) danger signals. Mostly, endogenous molecules (or their derivatives) have well-defined intracellular function but become danger signal when released or exposed following stress or injury. In this review, we discuss the potential role of ROS in chronic evolution of inflammatory cardiovascular diseases, using our experiences working on chagasic cardiomyopathy as a focus-point.

Parathyroid hormone accelerates decompensation following left ventricular hypertrophy

Parathyroid hormone (PTH) treatment was previously shown to improve cardiac function after myocardial infarction by enhancing neovascularization and cell survival. In this study, pressure overload-induced left ventricular hypertrophy (LVH) was induced in mice by transverse aortic banding (TAB) for 2 weeks. We subsequently evaluated the effects of a 2-week treatment with PTH or saline on compensated LVH. After another 4 weeks, the hearts of the mice were analyzed by echocardiography, histology, and molecular biology. Echocardiography showed that hearts of the PTH-treated mice have more severe failing phenotypes than the saline-treated mice following TAB with a greater reduction in fractional shortening and left ventricular posterior wall thickness and with a greater increase in left ventricular internal dimension. Increases in the heart weight to body weight ratio and lung weight to body weight ratio following TAB were significantly exacerbated in PTH-treated mice compared to saline-treated mice. Molecular markers for heart failure, fibrosis, and angiogenesis were also altered in accordance with more severe heart failure in the PTH-treated mice compared to the saline-treated mice following TAB. In addition, the PTH-treated hearts were manifested with increased fibrosis accompanied by an enhanced SMAD2 phosphorylation. These data suggest that the PTH treatment may accelerate the process of decompensation of LV, leading to heart failure.

Experimental therapies in hypertrophic cardiomyopathy

The quintessential clinical diagnostic phenotype of human hypertrophic cardiomyopathy (HCM) is primary cardiac hypertrophy. Cardiac hypertrophy is also a major determinant of mortality and morbidity including the risk of sudden cardiac death (SCD) in patients with HCM. Reversal and attenuation of cardiac hypertrophy and its accompanying fibrosis is expected to improve morbidity as well as decrease the risk of SCD in patients with HCM.The conventionally used pharmacological agents in treatment of patients with HCM have not been shown to reverse or attenuate established cardiac hypertrophy and fibrosis. An effective treatment of HCM has to target the molecular mechanisms that are involved in the pathogenesis of the phenotype. Mechanistic studies suggest that cardiac hypertrophy in HCM is secondary to activation of various hypertrophic signaling molecules and, hence, is potentially reversible. The hypothesis is supported by the results of genetic and pharmacological interventions in animal models. The results have shown potential beneficial effects of angiotensin II receptor blocker losartan, mineralocorticoid receptor blocker spironolactone, 3-hydroxy-3-methyglutaryl-coenzyme A reductase inhibitors simvastatin and atorvastatin, and most recently, N-acetylcysteine (NAC) on reversal or prevention of hypertrophy and fibrosis in HCM. The most promising results have been obtained with NAC, which through multiple thiol-responsive mechanisms completely reversed established cardiac hypertrophy and fibrosis in three independent studies. Pilot studies with losartan and statins in humans have established the feasibility of such studies. The results in animal models have firmly established the reversibility of established cardiac hypertrophy and fibrosis in HCM and have set the stage for advancing the findings in the animal models to human patients with HCM through conducting large-scale efficacy studies.

Additive beneficial effects of amlodipine and atorvastatin in reversing advanced cardiac hypertrophy in elderly spontaneously hypertensive rats

1. Additive beneficial effects on cardiovascular disease have been reported for amlodipine and atorvastatin. However, it is still unclear whether the combination of amlodipine and atorvastatin has additive beneficial effects on the regression of advanced cardiac hypertrophy in hypertension. In the present study, the effects of the drug combination on advanced cardiac hypertrophy were investigated in elderly spontaneously hypertensive rats (SHR). 2. Elderly SHR (36 weeks old) were randomly allocated into four groups of 12: (i) a vehicle-treated control group; (ii) an amlodipine (10 mg/kg per day)-treated group; (iii) an atorvastatin (10 mg/kg per day)-treated group; and (iv) a group treated with a combination of amlodipine and atorvastatin (both at 10 mg/kg per day). Drugs were administered by oral gavage every morning for a period of 12 weeks before hearts were harvested for analysis. 3. Combined administration of amlodipine and atorvastatin significantly suppressed cardiomyocyte hypertrophy, interstitial fibrosis and upregulation of hypertrophic and profibrotic genes, and also improved left ventricular diastolic dysfunction to a greater extent than did amlodipine monotherapy. Further beneficial effects of combination therapy on advanced cardiac hypertrophy were associated with a greater reduction of NADPH oxidase-mediated increases in cardiac reactive oxygen species (ROS), rather than decreased blood pressure and serum cholesterol levels. 4. To elucidate the underlying molecular mechanisms, we examined cardiovascular NADPH oxidase subunits and found that amlodipine clearly attenuated the expression of p47(phox) and p40(phox) and slightly but significantly reduced p22(phox) and Rac-1 levels in heart tissue. Combination treatment with amlodipine plus atorvastatin led to a further reduction in p22(phox), p47(phox) and Rac-1 protein levels compared with amlodipine alone. 5. In conclusion, combined amlodipine and atorvastatin treatment has a greater beneficial effect on advanced cardiac hypertrophy compared with amlodipine monotherapy. The benefits are likely to be related to the additive effects of the drugs on the suppression of NADPH oxidase-mediated ROS generation.

Spectrum of pleiotropic effects of statins in heart failure

The syndrome of heart failure is characterized by increased levels of circulating inflammatory mediators, which have been implicated in the pathogenesis of heart failure. Recently, a number of studies have suggested that statins may exert salutary effects in patients who have heart failure by virtue of their pleiotropic (non-lipid lowering) actions. This article focuses on the non-lipid lowering effects of statins, with an emphasis on the anti-inflammatory properties of these agents.

Effect of atorvastatin on plasma levels of asymmetric dimethylarginine in patients with non-ischaemic heart failure

BACKGROUND

Elevated plasma levels of asymmetric dimethylarginine (ADMA), an endothelial nitric oxide synthase (eNOS) inhibitor, may contribute to endothelial dysfunction in chronic heart failure (CHF). Since statins upregulate eNOS and ameliorate endothelial dysfunction in non-ischaemic CHF, we hypothesized that this may be in part through modification of ADMA.

AIM

To evaluate the effect of atorvastatin on the relationship between ADMA and endothelial function in non-ischaemic CHF.

METHODS

Twenty-four patients with CHF (ejection fraction <40%, New York Heart Association Functional Classes II and III) were randomised to atorvastatin treatment (40 mg) or placebo once daily for 6 weeks in a double-blinded, placebo-controlled crossover study. Plasma ADMA and l-arginine levels were measured by HPLC. Endothelial function was assessed by flow-mediated dilatation and invasive forearm plethysmography.

RESULTS

Post-statin therapy, endothelial function was improved (p<0.05) independent of LDL-cholesterol reductions, but no changes were observed in ADMA levels or the l-arginine to ADMA ratio. There was a trend for ADMA to inversely correlate with endothelial function at baseline.

CONCLUSIONS

Short-term atorvastatin treatment in non-ischaemic CHF improves endothelial function but has no effect on ADMA or the l-arginine to ADMA ratio. Our finding suggests that the observed statin-induced improvements in endothelial function are likely mediated via alternative pathways.

Statins: a perspective for left ventricular hypertrophy treatment

Left ventricular hypertrophy (LVH), despite its adaptive nature, is associated with an increased risk of cardiovascular morbidity and mortality. Achievement of LVH regression is thus considered a principal therapeutic aim. However, regression of LVH induced by various therapeutic means may exhibit differing patterns, with variable biological implications. Inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (statins) have been shown to induce prevention or regression of LVH in different models of pathological myocardial growth. In addition to reduction of LV mass, statins were shown to reduce myocardial fibrosis, increase capillary density network and attenuate electrical instability of the hypertrophied heart. Most importantly, statins improved systolic and diastolic LV function and even decreased mortality. The inhibition of hypertrophic growth was only partly achieved by reduction of haemodynamic overload. Direct mechanisms, such as inhibition of neurohumoral activation in the myocardial tissue, attenuated production of growth factors and markers of inflammation and reduction of oxidative stress also seem to participate. The protective effect of statins was associated with the inhibition of expression and activation of small guanosintriphosphate-binding proteins such as Ras and Rho, which control the intensity of oxidative stress, the production and availability of nitric oxide, and the expression of genes involved in myocardial growth. In addition to reduction of LV mass, statins may also improve the prognosis of LVH independently of their lipid-lowering effect.

Effect of atorvastatin on non-ischemic heart failure and matrix metalloproteinase-2 and 9 in rats

AIM

To examine the role of atorvastatin on volume-overload-induced heart failure and to test the hypothesis that atorvastatin inhibits MMP-2 and 9 expression in heart failure with non-ischemic etiology.

METHODS

Arteriovenous (AV) fistula-treated rats were administered with atorvastatin (3 mg/kg/d) or vehicle for 17 weeks. Ventricular hypertrophy and heart failure were assessed by echocardiography, B-type natriuretic peptide BNP mRNA level and morphological measurement. MMP-2, 9 expression were measured by Western blot and zymography.

RESULTS

Atorvastatin decreased left ventricular end diastolic diameter from 6.86+/-0.51 mm to 6.28+/-0.37 mm (P<0.05), increased fractioning shortening from 41.4%+/-4.5% to 52.7%+/-4.2% (P<0.01), decreased ratio of BNP/GAPDH mRNA level from 0.43+/-0.03 to 0.27+/-0.03 (P<0.05). Similar data were observed for morphological measurement. Protein expression and enzyme activity of MMP-2 and 9 in the left ventricle tissue were significantly increased 18 weeks after surgery and atorvastatin also prevented those changes.

CONCLUSION

Left ventricular remodeling induced by AV fistula was profoundly changed by atorvastatin treatment. Hypertrophy was attenuated and global function was improved. These positive effects of atorvastatin on heart failure were associated with decreased MMP-2 and 9 protein expression and enzyme activity.

Statins in heart failure. Beyond the lipid lowering effect

Statins, the most widely prescribed medications in patients with hyperlipidemia and coronary heart disease, have a number of pleiotropic actions beyond cholesterol lowering. They improve endothelial function, they have antioxidant and anti-inflammatory effects, they regulate neovascularization and have immunomodulatory activities. Experimental evidence suggests that statins may be beneficial in heart failure as they can inhibit myocardial hypertrophy, reduce cardiomyocyte loss by apoptosis, reduce oxidative stress and restore neurohormonal imbalance. Furthermore small randomised clinical trials showed that short term statin administration may improve key pathophysiological aspects of this syndrome. Finally retrospective analyses of large statin trials imply a long term profit on clinical outcome in this group of patients. These results however need to be reviewed with caution as certain studies have demonstrated that low serum cholesterol is associated with worse prognosis in HF and that ubiquinone levels, a micronutrient with antioxidant actions, reduces significantly following statin administration. Large prospective randomised controlled trials are needed to confirm the beneficial effect of statins on cardiovascular outcome in HF patients and further elucidate the contributing mechanisms. Finally the statin dose and the interaction with co-administered drugs need to be studied.

Lovastatin protects mesenchymal stem cells against hypoxia- and serum deprivation-induced apoptosis by activation of PI3K/Akt and ERK1/2

Cell therapy with bone marrow-derived mesenchymal stem cells (MSCs) has been shown to have great promises in cardiac repair after myocardial infarction. However, poor viability of transplanted MSCs in the infracted heart has limited the therapeutic efficacy. Our previous studies have shown in vitro that rat MSCs undergo caspase-dependent apoptosis in response to hypoxia and serum deprivation (Hypoxia/SD). Recent findings have implicated statins, an established class of cholesterol-lowering drugs, enhance the survival of cells under various conditions. In this study, we investigated the effect of lovastatin on rat MSCs apoptosis induced by Hypoxia/SD, focusing in particular on regulation of mitochondrial apoptotic pathway and the survival signaling pathways. We demonstrated that lovastatin (0.01-1 microM) remarkably prevented MSCs from Hypoxia/SD-induced apoptosis through inhibition of the mitochondrial apoptotic pathway, leading to attenuation of caspase-3 activation. The loss of mitochondrial membrane potential and cytochrome-c release from mitochondria to cytosol were significantly inhibited by lovastatin. Furthermore, the antiapoptotic effect of lovastatin on mitochondrial apoptotic pathway was effectively abrogated by both PI3K inhibitor, LY294002 and ERK1/2 inhibitor, U0126. The phosphorylations of Akt/GSK3 beta and ERK1/2 stimulated by lovastatin were detected. The activation of ERK1/2 was inhibited by a PI3K inhibitor, LY294002, but U0126, a ERK1/2 inhibitor did not inhibit phosphorylation of Akt and GSK3 beta. These data demonstrate that lovastatin protects MSCs from Hypoxia/SD-induced apoptosis via PI3K/Akt and MEK/ERK1/2 pathways, suggesting that it may prove a useful therapeutic adjunct for transplanting MSCs into damaged heart after myocardial infarction.

3-HMG-Coenzyme A Reductase Inhibition and Extracellular Matrix Gene Expression in the Pressure-Overloaded Rat Heart

The purpose of this study was to determine whether 3-HMG-Coenzyme A (HMG-CoA) reductase inhibition would attenuate the early pressure overload-induced activation of extracellular matrix genes in the left ventricle (LV) of the heart. Sprague-Dawley rats were randomized to 1 of 4 treatment groups: sham-operation+vehicle (SH-V), aortic constriction+vehicle (AC-V), AC+rosuvastatin (RSV, 2 mg/kg; AC-LO), and AC+RSV (10 mg/kg; AC-HI). Rats were injected with normal NaCl (V) or RSV once daily, beginning 1 day before surgery, and killed 1 or 3 days after surgery. Hemodynamic measurements were made in the open-chest anesthetized state. LV levels of transforming growth factor beta1 (TGF-beta1), procollagen 1 (C1), and fibronectin (FN) mRNA were measured by Northern blotting. AC induced a approximately 25% increase in LV weight after 3 days that was not altered by RSV treatment. LV expression of TGF-beta1, C1, and FN mRNA was approximately 2-fold, approximately 2.5-fold, and approximately 5-fold greater, respectively, in hearts of AC-V compared to SH-V rats 3 days post-operation, and was not significantly decreased by either dose of RSV. Inhibition of HMG-CoA reductase does not attenuate the pronounced aortic constriction-induced increases in the early expression of TGF-beta1, C1, and FN in this model of acute pressure overload of the rat heart.

Hypertensive heart disease

Left ventricular hypertrophy (LVH) and diastolic dysfunction (CHF-D) are the early manifestations of cardiovascular target organ damage in patients with arterial hypertension and signify hypertensive heart disease. Identification of hypertensive heart disease is critical, as these individuals are more prone to congestive heart failure, arrhythmias, myocardial infarction and sudden cardiac death. Regression of left ventricular (LV) mass with antihypertensive therapy decreases the risk of future cardiovascular events. The goal of antihypertensive therapy is to both lower blood pressure (BP) and interrupt BP-independent pathophysiologic processes that promote LVH and CHF-D. The purpose of this review is to summarize current and emerging approaches to the pathophysiology and treatment of hypertensive heart disease.

Roles of exercise and pharmacokinetics in cerivastatin-induced skeletal muscle toxicity

Three-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors are associated with adverse skeletal muscle effects, but the underlying mechanisms remain unclear. To determine whether toxicity involves the level of drug exposure in muscle tissue and to test the effect of exercise on cerivastatin (CVA)-induced skeletal muscle damage, female rats were administered vehicle or CVA at 0.1, 0.5, and 1.0 mg/kg/day by gavage for two weeks and exercised or not on treadmills for 20 min/day. Clinical chemistry and plasma and tissue pharmacokinetics were evaluated; light and transmission electron microscopy (TEM) of Type I and Type II fiber-predominant skeletal muscles were performed. Serum levels of AST, ALT, CK, and plasma lactic acid were significantly elevated dose-dependently. CVA treatment decreased psoas and quadriceps weights. At 1 mg/kg all muscles except soleus demonstrated degeneration. Exercise-exacerbated severity of CVA-induced degeneration was evident in all muscles sampled except soleus and quadriceps. Early mitochondrial involvement in toxicity is suggested by the numerous membranous whorls and degenerate mitochondria observed in muscles at 0.5 mg/kg. No significant differences in CVA concentrations between either EDL and soleus or plasma and muscle were found. We found that CVA had no effect on cleaved caspase 3. In summary, we found that treadmill exercise exacerbated the incidence and severity of CVA-induced damage in Type II fiber-predominant muscles. Tissue exposure is likely not the key factor mediating CVA-induced skeletal muscle toxicity.

Prevention of cardiac hypertrophy by atorvastatin in a transgenic rabbit model of human hypertrophic cardiomyopathy

Cardiac hypertrophy, a major determinant of morbidity and mortality in hypertrophic cardiomyopathy (HCM), is considered a secondary phenotype and potentially preventable. To test this hypothesis, we screened 30 5- to 6-month-old beta-myosin heavy chain Q403 transgenic rabbits by echocardiography and selected 26 without cardiac hypertrophy. We randomized the transgenic rabbits to treatment with atorvastatin (2.5 mg/Kg/d), known to block hypertrophic signaling or a placebo. We included 15 nontransgenic rabbits as controls. Cardiac phenotype was analyzed serially before, 6 and 12 months after randomization. Serum total cholesterol levels were reduced by 49% with atorvastatin administration. Left-ventricular mass, wall thickness; myocyte size, myocardial levels of molecular markers of hypertrophy, lipid peroxides, and oxidized mitochondrial DNA; and the number of terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL)-positive myocytes were increased significantly in the placebo but not in the atorvastatin group. Myocardium catalase mRNA levels were decreased by 5-fold in the placebo but were normal in the atorvastatin group. Catalase protein level and activity were not significantly changed. Levels of membrane-bound Ras and phospho-p44/42 mitogen-activated-protein kinase (MAPK) were increased in the placebo group (approximately 2.5 fold) but were reduced in the atorvastatin group. Levels of GTP- and membrane-bound RhoA and Rac1, phospho-p38, and phospho-c-Jun NH2-terminal kinases were unchanged. Thus, atorvastatin prevented development of cardiac hypertrophy; determined at organ, cellular, and molecular levels, partly through reducing active Ras and p44/42 MAPK. The results indicate potential beneficial effects of atorvastatin in prevention of cardiac hypertrophy, a major determinant of morbidity in all forms of cardiovascular diseases, and beckon clinical studies in humans with HCM.