Combined atorvastatin and coenzyme Q10 improve the left ventricular function in isoproterenol-induced heart failure in rat

Evaluation of Coenzyme Q10 (CoQ10) Deficiency and Therapy in Mouse Models of Cardiomyopathy

ABSTRACT

Mitochondrial dysfunction plays a key role in the development of heart failure, but targeted therapeutic interventions remain elusive. Previous studies have shown coenzyme Q10 (CoQ10) insufficiency in patients with heart disease with undefined mechanism and modest effectiveness of CoQ10 supplement therapy. Using 2 transgenic mouse models of cardiomyopathy owing to cardiac overexpression of Mst1 (Mst1-TG) or β 2 -adrenoceptor (β 2 AR-TG), we studied changes in cardiac CoQ10 content and alterations in CoQ10 biosynthesis genes. We also studied in Mst1-TG mice effects of CoQ10, delivered by oral or injection regimens, on both cardiac CoQ10 content and cardiomyopathy phenotypes. High performance liquid chromatography and RNA sequencing revealed in both models significant reduction in cardiac content of CoQ10 and downregulation of most genes encoding CoQ10 biosynthesis enzymes. Mst1-TG mice with 70% reduction in cardiac CoQ10 were treated with CoQ10 either by oral gavage or i.p. injection for 4-8 weeks. Oral regimens failed in increasing cardiac CoQ10 content, whereas injection regimen effectively restored the cardiac CoQ10 level in a time-dependent manner. However, CoQ10 restoration in Mst1-TG mice did not correct mitochondrial dysfunction measured by energy metabolism, downregulated expression of marker proteins, and oxidative stress nor to preserve cardiac contractile function. In conclusion, mouse models of cardiomyopathy exhibited myocardial CoQ10 deficiency likely due to suppressed endogenous synthesis of CoQ10. In contrast to ineffectiveness of oral administration, CoQ10 administration by injection regimen in cardiomyopathy mice restored cardiac CoQ10 content, which, however, failed in achieving detectable efficacy at molecular and global functional levels.

Time-dependent influence of infliximab on hemodynamic responses and cardiac injuries of isoproterenol-induced myocardial infarction in rats

Immune-induced inflammation plays an important role both in aggravating and healing of post myocardial infarction (MI) injuries. Potent anti-inflammatory and local immunomodulatory activity of infliximab has been suggested to have modulating effects on immune responses after MI. The aim of the present study was to evaluate the efficacy of infliximab on hemodynamic responses and myocardial injuries following isoproterenol-induced myocardial infarction. Male Wistar rats, weighting 260 ± 20 g were assigned into ten groups (n = 6) of saline (normal saline), infliximab (7 mg/kg), isoproterenol (100 mg/kg for two consecutive days), and isoproterenol plus infliximab (30 min after the second injection of isoproterenol). The heart tissues and serums were analyzed 24, 48, 72, and 96 h post-MI and hemodynamic parameters, histopathological changes, malondialdehyde (MDA), Total antioxidant capacity (TAC), lactate dehydrogenase (LDH), and lactate levels were assessed in the respective groups. Infliximab partially improved hemodynamic depression in the first days after MI, but the heart became more suppressed later. A similar result also obtained at the MDA tissue levels but not serum levels. Anti-inflammatory effects of Infliximab may improve cardiac function and prevent heart tissue injury early after MI; however, it can worsen the condition later by inhibiting compensatory reactions such as cardiac remodeling and tissue repair.

Nephroprotective Effect of Coenzyme Q10 alone and in Combination with N-acetylcysteine in Diabetic Nephropathy

Aim

Oxidative stress due to chronic hyperglycaemia is a key factor in the development and progression of various microvascular complications including diabetic nephropathy (DN) and associated renal injury. Treatment with antioxidants is one of the strategies to protect the kidney from oxidative tissue damage to improve renal physiology during DN. The investigation, therefore, was designed to assess the nephroprotective effect of coenzyme Q10 (CoQ10) and N-acetylcysteine (NAC), either alone or in combination in streptozotocin (STZ)-nicotinamide (NAD) induced diabetic nephropathy (DN) in rats.

Methods

T2DM induced by STZ (55 mg/kg, i.p.)-NAD (110 mg/kg, i.p.) in Sprague-Dawley rats (220–250 g) was confirmed by the elevated blood glucose level and glycated haemoglobin. DN was assessed by renal function tests. The diabetic rats were treated with CoQ10 (10 mg/kg, p.o.) and/or NAC (300 mg/kg, p.o.) for 8 weeks after confirmation of DN. Oxidative tissue damage due to STZ-NAD was estimated by malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT), reduced glutathione (GSH), myeloperoxidase (MPO) and nitric oxide (NO) in the renal homogenate.

Results

Data showed significant alteration in serum and urinary creatinine, total protein, albumin, serum urea, blood urea nitrogen (BUN) and uric acid in diabetic animals as compared to the control rats. CoQ10 and/or NAC effectively alleviated the disturbances in renal function. Diabetic rats showed increased MDA, decreased SOD and CAT activities and decreased GSH along with a significant increase in MPO activity and nitrite content. Treatment with the aforementioned antioxidants and their combination ameliorated the kidney damage as indicated by the reduced OS with improved renal function.

Conclusion

The investigation suggests that the chronic hyperglycaemia-induced OS leads to the development and progression of DN. The combined treatment with CoQ10 and NAC has shown a remarkable nephroprotective effect suggesting that combined antioxidant therapy with CoQ10 and NAC may be useful in the attenuation of DN.

CoenzymeQ in cellular redox regulation and clinical heart failure

Coenzyme Q (CoQ) is ubiquitously embedded in lipid bilayers of various cellular organelles. As a redox cycler, CoQ shuttles electrons between mitochondrial complexes and extramitochondrial reductases and oxidases. In this way, CoQ is crucial for maintaining the mitochondrial function, ATP synthesis, and redox homeostasis. Cardiomyocytes have a high metabolic rate and rely heavily on mitochondria to provide energy. CoQ levels, in both plasma and the heart, correlate with heart failure in patients, indicating that CoQ is critical for cardiac function. Moreover, CoQ supplementation in clinics showed promising results for treating heart failure. This review provides a comprehensive view of CoQ metabolism and its interaction with redox enzymes and reactive species. We summarize the clinical trials and applications of CoQ in heart failure and discuss the caveats and future directions to improve CoQ therapeutics.

Pharmacokinetics and tissue distribution study of 18 bioactive components in healthy and chronic heart failure rats after oral administration of Qi-Shen-Ke-Li formula using ultra-high-performance liquid chromatography/triple quadrupole mass spectrometry

RATIONALE

Qi-Shen-Ke-Li (QSKL) is a traditional Chinese formula used in clinical practice to treat chronic heart failure (CHF) in humans. To rationalize the use of this formula in clinical practice, the pharmacokinetics and tissue distribution in rats after oral administration of QSKL were investigated using ultra-high-performance liquid chromatography/triple quadrupole mass spectrometry (UHPLC/TQ-MS).

METHODS

The CHF model was induced by intraperitoneal injection of isoprenaline (ISO; also known as isoproterenol) and evaluated by HE staining and brain natriuretic peptide (BNP) measurement. The UHPLC/TQ-MS method was then applied to determine the concentrations of 18 bioactive components in rat plasma and tissues of heathy and CHF rats after oral administration of QSKL. This was followed by investigating the pharmacokinetics and tissue distribution profiles of these bioactive compounds in the heathy and CHF rats.

RESULTS

The pharmacokinetics results showed that the duration time of two compounds was prolonged, the absorption rate of four compounds was accelerated, and the bioavailability of four compounds was increased in the CHF rats compared with the healthy rats. Meanwhile, the tissue distribution results showed that the QSKL formula could be distributed rapidly and widely in different rat tissues. The bioavailability of eight compounds in the liver was enhanced in CHF rats. This suggested that the drug/toxic effects should be considered in clinical practice, as drug-drug interactions might occur in liver metabolism during the drug combination.

CONCLUSIONS

The pharmacokinetic profiles and tissue distribution of 18 bioactive compounds in QSKL are altered by the CHF status. This study provides insight for better clinical applications of this formula in the future and lays the foundation for the development of a new drug for chronic heart failure based on the QSKL formula.

Pathophysiological Basis for Nutraceutical Supplementation in Heart Failure: A Comprehensive Review

There is evidence demonstrating that heart failure (HF) occurs in 1-2% of the global population and is often accompanied by comorbidities which contribute to increasing the prevalence of the disease, the rate of hospitalization and the mortality. Although recent advances in both pharmacological and non-pharmacological approaches have led to a significant improvement in clinical outcomes in patients affected by HF, residual unmet needs remain, mostly related to the occurrence of poorly defined strategies in the early stages of myocardial dysfunction. Nutritional support in patients developing HF and nutraceutical supplementation have recently been shown to possibly contribute to protection of the failing myocardium, although their place in the treatment of HF requires further assessment, in order to find better therapeutic solutions. In this context, the Optimal Nutraceutical Supplementation in Heart Failure (ONUS-HF) working group aimed to assess the optimal nutraceutical approach to HF in the early phases of the disease, in order to counteract selected pathways that are imbalanced in the failing myocardium. In particular, we reviewed several of the most relevant pathophysiological and molecular changes occurring during the early stages of myocardial dysfunction. These include mitochondrial and sarcoplasmic reticulum stress, insufficient nitric oxide (NO) release, impaired cardiac stem cell mobilization and an imbalanced regulation of metalloproteinases. Moreover, we reviewed the potential of the nutraceutical supplementation of several natural products, such as coenzyme Q10 (CoQ10), a grape seed extract, Olea Europea L.-related antioxidants, a sodium-glucose cotransporter (SGLT2) inhibitor-rich apple extract and a bergamot polyphenolic fraction, in addition to their support in cardiomyocyte protection, in HF. Such an approach should contribute to optimising the use of nutraceuticals in HF, and the effect needs to be confirmed by means of more targeted clinical trials exploring the efficacy and safety of these compounds.

Coenzyme Q10 Alleviated Behavioral Dysfunction and Bioenergetic Function in an Animal Model of Depression

Coenzyme Q₁₀ (CoQ₁₀) is a natural compound, is involved in the mitochondrial electron transfer chain (ETC) and plays an important pattern in adenosine triphosphate (ATP) production. Amelioration of ATP is related to abnormalities in cognitive function and psychiatric diseases. Previous studies have shown that depression is accompanied by the induction of inflammatory and oxidative stress pathways and amelioration of antioxidant status. In a recent study, we investigated the beneficial effects of CoQ₁₀ on behavioral dysfunction and CoQ₁₀ level in the rat brain. Therefore, intracerebroventricular (ICV) infusion of a single dose of streptozotocin (STZ, 0.2 mg/mouse) was used in adult male mice to induce depression. The behavioral data revealed a significant difference between the depression and control groups regarding the forced swim test (FST) and splash test results at 24 h following STZ treatment. Also, the validated and accurate high-performance liquid chromatography (HPLC) technique showed decreased CoQ₁₀ level in the brain samples of the STZ group, compared to the controls. Our findings revealed that behavioral abnormalities due to STZ target mitochondria and affect energy metabolism and hemostasis, resulting in the initiation of oxidative damage in the brain. Besides, 4-week administration of CoQ₁₀ could reverse the depressive like behavior and bioenergetic effects of STZ in the treated groups.

Targeting mitochondrial dysfunction and oxidative stress in heart failure: Challenges and opportunities

Mitochondrial dysfunction characterized by impaired bioenergetics, oxidative stress and aldehydic load is a hallmark of heart failure. Recently, different research groups have provided evidence that selective activation of mitochondrial detoxifying systems that counteract excessive accumulation of ROS, RNS and reactive aldehydes is sufficient to stop cardiac degeneration upon chronic stress, such as heart failure. Therefore, pharmacological and non-pharmacological approaches targeting mitochondria detoxification may play a critical role in the prevention or treatment of heart failure. In this review we discuss the most recent findings on the central role of mitochondrial dysfunction, oxidative stress and aldehydic load in heart failure, highlighting the most recent preclinical and clinical studies using mitochondria-targeted molecules and exercise training as effective tools against heart failure.

Effect of concomitant administration of coenzyme Q10 with sitagliptin on experimentally induced diabetic nephropathy in rats

This study was aimed to investigate the therapeutic potential of coenzyme Q10 and its combination with sitagliptin in experimentally induced diabetic nephropathy. The diabetic rats were treated with coenzyme Q10 or sitagliptin and their concomitant administration. Various parameters of renal function like serum creatinine, urea, uric acid and markers of oxidative stress such as renal malondialdehyde content (MDA), glutathione (GSH) level and superoxide dismutase (SOD), catalase activities were measured. TNF-α, TGF-β, MPO activity and nitrite content were estimated in renal tissue with histopathological observation. Diabetic rats showed a significant reduction in renal function, which was reflected with an increase in serum creatinine, urea and uric acid levels. Streptozotocin-nicotinamide caused renal tubular damage with a higher MDA level, depletion of SOD and CAT activity and GSH level. In addition, TNF-α, TGF- β, MPO activity and nitrite content were significantly increased in diabetic rats. Treatment with coenzyme Q10 or sitagliptin and their co-administration ameliorated STZ-nicotinamide-induced renal damage which was reflected by decreased oxidative stress, TNF-α, TGF-β, MPO activity, nitrite content along with histopathological changes. To conclude, concomitant administration of coenzyme Q10 and sitagliptin showed a better renoprotective effect than coenzyme Q10 or sitagliptin when given alone.

Atorvastatin Improves Ventricular Remodeling after Myocardial Infarction by Interfering with Collagen Metabolism

Purpose

Therapeutic strategies that modulate ventricular remodeling can be useful after acute myocardial infarction (MI). In particular, statins may exert effects on molecular pathways involved in collagen metabolism. The aim of this study was to determine whether treatment with atorvastatin for 4 weeks would lead to changes in collagen metabolism and ventricular remodeling in a rat model of MI.

Methods

Male Wistar rats were used in this study. MI was induced in rats by ligation of the left anterior descending coronary artery (LAD). Animals were randomized into three groups, according to treatment: sham surgery without LAD ligation (sham group, n = 14), LAD ligation followed by 10mg atorvastatin/kg/day for 4 weeks (atorvastatin group, n = 24), or LAD ligation followed by saline solution for 4 weeks (control group, n = 27). After 4 weeks, hemodynamic characteristics were obtained by a pressure-volume catheter. Hearts were removed, and the left ventricles were subjected to histologic analysis of the extents of fibrosis and collagen deposition, as well as the myocyte cross-sectional area. Expression levels of mediators involved in collagen metabolism and inflammation were also assessed.

Results

End-diastolic volume, fibrotic content, and myocyte cross-sectional area were significantly reduced in the atorvastatin compared to the control group. Atorvastatin modulated expression levels of proteins related to collagen metabolism, including MMP1, TIMP1, COL I, PCPE, and SPARC, in remote infarct regions. Atorvastatin had anti-inflammatory effects, as indicated by lower expression levels of TLR4, IL-1, and NF-kB p50.

Conclusion

Treatment with atorvastatin for 4 weeks was able to attenuate ventricular dysfunction, fibrosis, and left ventricular hypertrophy after MI in rats, perhaps in part through effects on collagen metabolism and inflammation. Atorvastatin may be useful for limiting ventricular remodeling after myocardial ischemic events.

Bilateral Renal Denervation Ameliorates Isoproterenol-Induced Heart Failure through Downregulation of the Brain Renin-Angiotensin System and Inflammation in Rat

Heart failure (HF) is characterized by cardiac dysfunction along with autonomic unbalance that is associated with increased renin-angiotensin system (RAS) activity and elevated levels of proinflammatory cytokines (PICs). Renal denervation (RD) has been shown to improve cardiac function in HF, but the protective mechanisms remain unclear. The present study tested the hypothesis that RD ameliorates isoproterenol- (ISO-) induced HF through regulation of brain RAS and PICs. Chronic ISO infusion resulted in remarked decrease in blood pressure (BP) and increase in heart rate and cardiac dysfunction, which was accompanied by increased BP variability and decreased baroreflex sensitivity and HR variability. Most of these adverse effects of ISO on cardiac and autonomic function were reversed by RD. Furthermore, ISO upregulated mRNA and protein expressions of several components of the RAS and PICs in the lamina terminalis and hypothalamic paraventricular nucleus, two forebrain nuclei involved in cardiovascular regulations. RD significantly inhibited the upregulation of these genes. Either intracerebroventricular AT1-R antagonist, irbesartan, or TNF-α inhibitor, etanercept, mimicked the beneficial actions of RD in the ISO-induced HF. The results suggest that the RD restores autonomic balance and ameliorates ISO-induced HF and that the downregulated RAS and PICs in the brain contribute to these beneficial effects of RD.

Coenzyme Q10 and Heart Failure: A State-of-the-Art Review

Heart failure (HF) with either preserved or reduced ejection fraction is associated with increased morbidity and mortality. Evidence-based therapies are often limited by tolerability, hypotension, electrolyte disturbances, and renal dysfunction. Coenzyme Q10 (CoQ10) may represent a safe therapeutic option for patients with HF. CoQ10 is a highly lipophilic molecule with a chemical structure similar to vitamin K. Although being a common component of cellular membranes, CoQ10's most prominent role is to facilitate the production of adenosine triphosphate in the mitochondria by participating in redox reactions within the electron transport chain. Numerous trials during the past 30 years examining CoQ10 in patients with HF have been limited by small numbers and lack of contemporary HF therapies. The recent publication of the Q-SYMBIO randomized controlled trial demonstrated a reduction in major adverse cardiovascular events with CoQ10 supplementation in a contemporary HF population. Although having limitations, this study has renewed interest in evaluating CoQ10 supplementation in patients with HF. Current literature suggests that CoQ10 is relatively safe with few drug interactions and side effects. Furthermore, it is already widely available as an over-the-counter supplement. These findings warrant future adequately powered randomized controlled trials of CoQ10 supplementation in patients with HF. This state-of-the-art review summarizes the literature about the mechanisms, clinical data, and safety profile of CoQ10 supplementation in patients with HF.

Effect of coenzyme Q10 alone and its combination with metformin on streptozotocin-nicotinamide-induced diabetic nephropathy in rats

Objectives:

This study was aimed to investigate the therapeutic potential of coenzyme Q10 and its combination with metformin on streptozotocin (STZ)-nicotinamide-induced diabetic nephropathy (DN).

Materials and Methods:

Type 2 diabetes in rats was induced with STZ-nicotinamide. The diabetic rats were treated with coenzyme Q10 (10 mg/kg, p.o.) alone or coenzyme Q10 + metformin. Various parameters of renal function tests such as serum creatinine, urea, uric acid, and markers of oxidative stress such as renal malondialdehyde (MDA) level, superoxide dismutase (SOD), and catalase (CAT) activities were measured. Tumor necrosis factor-α (TNF-α), myeloperoxidase (MPO) activity, transforming growth factor-β (TGF-β), and nitrite content were estimated in renal tissues. All treated animal were subjected to histopathological changes of kidney.

Result:

Diabetic rats showed a significant reduction in renal function, which was reflected with an increase in serum urea, serum creatinine, uric acid. In addition, STZ-nicotinamide caused renal tubular damage with a higher MDA level, depletion of SOD and CAT activity and glutathione (GSH) level. Moreover, TNF-α, MPO activity, TGF-β, and nitrite content were significantly increased in diabetic rats, while treatment with coenzyme Q10 or metformin or their combination ameliorate STZ-nicotinamide induced renal damage due to improvement in renal function, oxidative stress, suppression of TNF-α, MPO activity, TGF-β and nitrite content along with histopathological changes.

Conclusions:

This finding suggests that the treatment with coenzyme Q10 or metformin showed significant renoprotective effect against STZ-nicotinamide-induced DN. However, concomitant administration of both showed a better renoprotective effect than coenzyme Q10 or metformin alone treatment.

Bone marrow-derived multipotent stromal cells promote myocardial fibrosis and reverse remodeling of the left ventricle

Cell therapy is increasingly recognized as a beneficial practice in various cardiac conditions, but its fundamentals remain largely unclear. The fates of transplanted multipotent stromal cells in postinfarction cardiac microenvironments are particularly understudied. To address this issue, labeled multipotent stromal cells were infused into rat myocardium at day 30 after myocardial infarction, against the background of postinfarction cardiosclerosis. Therapeutic effects of the transplantation were assessed by an exercise tolerance test. Histological examination at 14 or 30 days after the transplantation was conducted by means of immunostaining and quantitative image analysis. An improvement in the functional status of the cardiovascular system was observed after both the autologous and the allogeneic transplantations. Location of the label-positive cells within the heart was restricted to the affected part of myocardium. The transplanted cells could give rise to fibroblasts or myofibroblasts but not to cardiac myocytes or blood vessel cells. Both types of transplantation positively influenced scarring processes, and no expansion of fibrosis to border myocardium was observed. Left ventricular wall thickening associated with reduced dilatation index was promoted by transplantation of the autologous cells. According to the results, multipotent stromal cell transplantation prevents adverse remodeling and stimulates left ventricular reverse remodeling.

Tacrolimus ameliorates functional disturbances and oxidative stress in isoproterenol-induced myocardial infarction

BACKGROUND

The inflammatory responses play a major role in the pathogenesis of acute myocardial infarction (MI). Early inhibition of inflammation may improve post MI cardiac function. The aim of this study was to investigate the effects of tacrolimus on cardiac function, hemodynamic parameters as well as histopathologic and electrocardiographic changes in isoproterenol-induced myocardial infarction.

METHODS

Male Wistar rats were randomly divided into six groups of control, isoproterenol alone, tacrolimus alone, and isoproterenol plus tacrolimus (0.5, 1 and 2 mg/kg). Isoproterenol (100 mg/kg) was injected subcutaneously for two consecutive days to induce myocardial infarction, and simultaneously tacrolimus was administered orally twice a day for three days.

RESULTS AND CONCLUSIONS

Administration of isoproterenol resulted in myocardial edema and necrosis as well as a marked reduction in the left ventricular systolic pressure (LVSP), left ventricular contractility (LVdP/dtmax) and relaxation (LVdP/dtmin) along with a severe elevation in left ventricular end-diastolic pressure (LVEDP). Isoproterenol also elevated the ST-segment and suppressed the R-amplitude and R-R interval on ECG. It was found that all doses of tacrolimus could amend the ECG pattern and ameliorated the isoproterenol induced disturbances in cardiac function. Acute and short term treatment with tacrolimus at dose of 2 mg/kg significantly (P < 0.001) improved LVdP/dtmax from 2712 ± 82 in myocardial infarcted rats to 4592 ± 149 mmHg/sec. Similarly, tacrolimus lowered LVEDP from 17.6 ± 0.68 in MI group to the value of 5.6 ± 0.22 mmHg (P < 0.001). Furthermore, tacrolimus was found to reduce malondialdehyde concentration in serum and myocardium by 50-70% (P < 0.001).

Echocardiographic assessment of β-adrenoceptor stimulation-induced heart failure with reduced heart rate in mice

1. Chronic injection with the β-adrenoceptor (β-AR) agonist isoproterenol (ISO) has been commonly used as an animal model of β-AR-induced cardiac remodelling and heart failure. This ISO-treated model usually exhibits significantly decreased conscious heart rate (HR). However, the HR in treatment groups is usually adjusted to the same levels by anaesthesia to assess cardiac geometry and function. In the present study, we report a method of echocardiographic assessment that represents the true cardiac geometry and function under conditions of ISO withdrawal. 2. Briefly, C57BL/6 mice were treated with 5 mg/kg per day ISO for 12 weeks. Cardiac geometry and function were assessed by high-resolution echocardiography in vehicle (saline) - and ISO-treated mice that were either conscious or anaesthetized using different concentrations of isoflurane. 3. The cardiac β-AR response was decreased in ISO-treated mice, as evidenced by markedly decreased conscious HR. Vehicle- and ISO-treated mice did not differ in terms of cardiac geometry or function when HR was adjusted to the same level (400 b.p.m.) in both treatment groups, but cardiac geometry and function did differ when a low (1%) rather than high (1.5% or 2%) isoflurane concentration was used to adjust HR. Furthermore, 3 day ISO withdrawal eliminated the difference in conscious HR between the two groups. In addition, the groups differed in cardiac geometry and function regardless of the isoflurane concentration used. 4. In conclusion, using isoflurane to decrease the HR of treated groups to the same level may mask left ventricular dysfunction in ISO-treated mice. Withdrawal of ISO eliminated the difference in basal HR between the ISO-treated and control groups on echocardiography, allowing a more accurate assessment of cardiac pathological and functional changes.

Exploration of pharmacological interventions to prevent isoproterenol-induced myocardial infarction in experimental models

High incidences of myocardial infarction associated with high morbidity and mortality, are a major concern and economic burden on industrialized nations. Persistent β-adrenergic receptor stimulation with isoproterenol leads to the development of oxidative stress, myocardial inflammation, thrombosis, platelet aggregation and calcium overload, which ultimately cause myocardial infarction. Therapeutic agents that are presently employed for the prevention and management of myocardial infarction are beta-blockers, antithrombotics, thrombolytics, statins, angiotensin converting enzyme inhibitors, angiotensin II type 1 receptor blockers, calcium channel blockers and nitrovasodilators. In spite of effective available interventions, the mortality rate of myocardial infarction is progressively increasing. Thus, there has been a regular need to develop effective therapies for the prevention and management of this insidious disease. In this review, the authors give an overview of the consequences of isoproterenol in the pathogenesis of cardiac disorders and various therapeutic possibilities to prevent these disorders.

Marrubium vulgare L. methanolic extract inhibits inflammatory response and prevents cardiomyocyte fibrosis in isoproterenol-induced acute myocardial infarction in rats

Introduction: Nowadays, finding new therapeutic compounds from natural products for treatment and prevention of a variety of diseases including cardiovascular disorders is getting a great deal of attention. This approach would result in finding new drugs which are more effective and have fewer side effects than the conventional medicines. The present study was designed to investigate the anti-inflammatory effect of the methanolic extract of Marrubiumvulgare, a popular traditional medicinal herb, on isoproterenol-induced myocardial infarction (MI) in rat model.

Methods: Male Wistar rats were assigned to 6 groups of control, sham, isoproterenol, and treatment with 10, 20, and 40 mg/kg/12h of the extract given orally concurrent with MI induction. A subcutaneous injection of isoproterenol (100 mg/kg/day) for two consecutive days was used to induce MI. Then, histopathological changes and inflammatory markers were evaluated.

Results: Isoproterenol injection increased inflammatory response, as shown by a significant increase in peripheral neutrophil count, myocardial myeloperoxidase (MPO) activity and serum levels of creatinine kinase-MB (CK-MB) and TNF-α (p<0.001). In the groups treated with 10, 20 and 40 mg/kg of M.vulgare extract serum CK-MB was subsided by 55.4%, 52.2% and 69%, respectively. Also treatment with the extract (40 mg/kg) significantly reduced (p<0.001) MPO activity in MI group. The levels of TNF-α was also considerably declined in the serums of MI group (p<0.001). In addition, peripheral neutrophil count, was significantly lowered by all doses of the extract (p<0.001). Interstitial fibrosis significantly was attenuated in treated groups compared with control MI group.

Conclusion: The results of study demonstrate that the M. vulgare extract has strong protective effects against isoproterenol-induced myocardial infarction and it seems possible that this protection is due to its anti-inflammatory effects.

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.

Regulation of antioxidant system, lipids and fatty acid β-oxidation contributes to the cardioprotective effect of sodium tanshinone IIA sulphonate in isoproterenol-induced myocardial infarction in rats

OBJECTIVE

Myocardial infarction (MI) is a cause of high morbidity and mortality in the world. Sodium tanshinone IIA sulphonate (STS) has been well used in Oriental medicine for treating cardiovascular diseases, however, the underlying mechanisms remain unclear. Alterations of circulating lipid profiles, increased fatty acid β-oxidation and oxidative stress play most important roles in the pathogenesis of MI. The present study aims to elucidate whether STS possesses cardioprotective effect against MI driven by isoproterenol (ISO), and to investigate its potential mechanisms of action.

METHODS

MI was induced by subcutaneous injection of ISO (85 mg/kg at interval of 24 h for 2 consecutive days) to rats. The rats were randomly divided into 6 groups: (1) control; (2) ISO; (3) STS (16 mg/kg) +control; (4-6) STS (16, 8, 4 mg/kg) +ISO.

RESULTS

Our study showed that STS could ameliorate cardiac dysfunction and variation of myocardial zymogram, up-regulate antioxidant systems, and maintain the levels of circulating lipids driven by supramaximal doses ISO as well. Moreover, modulation of redox-sensitive extracellular signal-regulated kinase1/2 (ERK1/2)/Nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) and AMP-activated protein kinase (AMPK)/acetyl CoA carboxylase (ACC)/carnitine palmitoyltransferase (CPT) 1 pathways were involved in STS induced cardioprotection.

CONCLUSIONS

STS exerts strong favorable cardioprotective action. Additionally, the properties of STS, such as anti-dyslipidemia, anti-oxidant and inhibition of fatty acid β-oxidation, may be the mechanisms underlying the observed results.

Effects of long-term atorvastatin treatment on cardiac aging

A number of studies have reported that atorvastatin (AVT) may have an important role in the delay of cardiac aging. However, the mechanism by which AVT affects cardiac aging has not been established. In this study, a series of experiments were performed to investigate the effects of AVT treatment on the cardiovascular system and the associated mechanism. Wistar rats were administered AVT or saline for 4 months. Age-related changes in the hearts were measured at the end of the experiment. The results showed that compared with young rats, the aged rats had significant changes indicative of myocardial aging, including increased blood lipid 1evelss, increased body weight, cardiac hypertrophy, larger myocardial cells, irregular muscle fibers, fewer deeply stained nuclei, smaller intercellular spaces, a larger number of apoptotic cells and increased levels of lipofuscin in myocardial tissue. However, long-term AVT treatment was able to significantly delay or even reverse these aging-related changes. In addition, these effects showed a certain dose-dependence. In general, long-term AVT treatment reduces blood lipids, inhibits cardiac hypertrophy, suppresses cardiomyocyte apoptosis and lowers the level of oxidative stress to protect the heart from aging.

Coenzyme Q10 supplementation and diastolic heart functions in hemodialysis patients: a randomized double-blind placebo-controlled trial

Coenzyme Q10 (CoQ10) supplementation has been shown to improve diastolic heart function in various patient cohorts. Systolic and diastolic dysfunctions are common in patients with end-stage renal disease. Favorable effects of CoQ10 on cardiac functions are yet to be seen in hemodialysis patients. We aimed to evaluate effect of CoQ10 supplementation on diastolic function in a cohort of maintenance hemodialysis patients. This was a prospective, double-blind, placebo-controlled, crossover study in which all patients received placebo and oral CoQ10 200 mg/d during the 8 weeks in each phase, with a 4-week washout period. Participants underwent conventional and tissue Doppler echocardiography before and after each study phase. Parameters characterizing left ventricle diastolic function and other standard echocardiographic measurements were recorded. Twenty-eight patients were randomized, but 22 patients completed study protocol. Intraventricular septum (IVS) thickness and left ventricle mass were significantly decreased in CoQ10 group (P = 0.03 and P = 0.01, respectively). Myocardial peak systolic and early diastolic velocities derived from IVS were significantly increased (P = 0.048 and P = 0.04, respectively). Isovolumetric relaxation time and E/Em ratio calculated for IVS also significantly reduced in CoQ10 group (p = 0.02 and p = 0.04, respectively). There was no significant difference in any of the studied echocardiographic parameters in placebo group. The results of this study showed that CoQ10 supplementation did not significantly improved diastolic heart functions compared with placebo in maintenance hemodialysis patients.

Phytochemical screening and evaluation of cardioprotective activity of ethanolic extract of Ocimum basilicum L. (basil) against isoproterenol induced myocardial infarction in rats

BACKGROUND AND THE PURPOSE OF THE STUDY

The objectives of the present study were phytochemical screening and study of the effects of ethanolic extract of aerial parts of Ocimum basilicum (basil) on cardiac functions and histopathological changes in isoproterenol-induced myocardial infarction (MI).

METHODS

The leaves of the plant were extracted with ethanol by maceration and subjected to colorimetry to determine flavonoids and phenolic compounds. High-performance TLC analysis and subsequent CAMAG's TLC scanning were performed to quantify rosmarinic acid content. Wistar rats were assigned to 6 groups of normal control, sham, isoproterenol, and treatment with 10, 20, and 40 mg/kg of the extract two times per day concurrent with MI induction. A subcutaneous injection of isoproterenol (100 mg/kg/day) for 2 consecutive days was used to induce MI.

RESULTS

Phytochemical screening indicated the presence of phenolic compounds (5.36%) and flavonoids (1.86%). Rosmarinic acid was the principal phenolic compound with a 15.74% existence. The ST-segment elevation induced by isoproterenol was significantly suppressed by all doses of the extract. A severe myocardial necrosis and fibrosis with a sharp reduction in left ventricular contractility and a marked increase in left ventricular end-diastolic pressure were seen in the isoproterenol group, all of which were significantly improved by the extract treatment. In addition to in-vitro antioxidant activity, the extract significantly suppressed the elevation of malondialdehyde levels both in the serum and the myocardium.

CONCLUSION

The results of the study demonstrate that Ocimum basilicum strongly protected the myocardium against isoproterenol-induced infarction and suggest that the cardioprotective effects could be related to antioxidative activities.

Rosuvastatin promotes angiogenesis and reverses isoproterenol-induced acute myocardial infarction in rats: role of iNOS and VEGF

Several reports highlighted the cardioprotective effect of statins after different types of ischemic injury. We studied the effect of rosuvastatin on acute myocardial infarction induced experimentally in rats focusing on angiogenesis as a potential mechanism underlying the drug effect. Acute myocardial infarction was induced by injecting the rats with two doses of isoproterenol (85 mg/kg/24 h, s.c.). Rats were examined for their electrocardiographic pattern and myocardial fibrosis one week after injection of isoproterenol (time for initiating therapy) and eight weeks thereafter (the end of therapeutic period) to examine the progression of the injury. Examination of the heart tissues at the end of week 9 showed a non significant decrease in the degree of myocardial fibrosis compared to those observed at week 1, indicating a slow rate of recovery from isoproterenol-induced injury. Treatment with rosuvastatin (5 or 10 mg/kg) for 8 weeks in myocardial-infarct rats enhanced the electrocardiographic pattern, reduced serum cardiac biomarkers, reduced tissue tumor necrosis factor-α (TNF-α) and upregulated vascular endothelial growth factor (VEGF) level. In addition, immunohistochemical staining revealed higher expression of inducible nitric oxide synthase (iNOS), VEGF and CD(34) (a marker for microvessel density) in the cardiac tissues after treatment with rosuvastatin compared to control group. The immunostaining for VEGF was positively correlated with microvessel density and iNOS. Overall, the current results provide evidence that the effect of rosuvastatin on myocardial-infarct rats involves induction of angiogenesis.

Low-dose atorvastatin, losartan, and particularly their combination, provide cardiovascular protection in isolated rat heart and aorta

Statins and angiotensin receptor blockers at therapeutic doses have beneficial cardiovascular effects, which can be applied for cardiovascular protection. We explored whether low doses of atorvastatin, losartan, and particularly their combination, possess important pleiotropic vasodilatory effects. Wistar rats were treated daily with low-dose atorvastatin (2 mg/kg, n = 15), low-dose losartan (5 mg/kg, n = 15), their combination (n = 15), or saline (n = 15). After 4, 6, or 8 weeks the animals were anesthetized, blood samples taken, and their hearts and thoracic aortas isolated. Two kinds of experiments were performed: the measurement of coronary flow rate after ischemia/reperfusion myocardial injury and endothelium-dependent relaxation of thoracic aorta. In both models, maximal vasodilation activity was obtained in rats treated for 6 weeks. In the ischemia/reperfusion myocardial injury model, coronary flow increased (atorvastatin or losartan 1.9-fold, P < 0.01; combination 2.4-fold, P < 0.001) compared with controls. In the thoracic aorta model, endothelium-dependent relaxation significantly increased only in the combination group compared with the control group (up to 1.4-fold; P < 0.01). Simultaneously, we detected increased anti-inflammatory activity and increased nitric oxide concentration, but no changes in lipids and blood pressure. In a rat model we showed important vasodilatory activity of low-dose atorvastatin, losartan, and particularly their combination. The effects of the low-dose combination were accompanied by, and probably at least partly achieved by, anti-inflammatory and nitric oxide pathways. Overall, these results could be valuable for the development of new vascular protective strategies focusing on a low-dose regimen of statins and sartans, and particularly their combination.