Metabolic and endothelial effects of trimetazidine on forearm skeletal muscle in patients with type 2 diabetes and ischemic cardiomyopathy

Role of Trimetazidine in Ameliorating Endothelial Dysfunction: A Review

Endothelial dysfunction is a hallmark of cardiovascular diseases, contributing to impaired vasodilation, altered hemodynamics, and atherosclerosis progression. Trimetazidine, traditionally used for angina pectoris, exhibits diverse therapeutic effects on endothelial dysfunction. This review aims to elucidate the mechanisms underlying trimetazidine's actions and its potential as a therapeutic agent for endothelial dysfunction and associated cardiovascular disorders. Trimetazidine enhances vasodilation and hemodynamic function by modulating endothelial nitric oxide synthase activity, nitric oxide production, and endothelin-1. It also ameliorates metabolic parameters, including reducing blood glucose, mitigating oxidative stress, and dampening inflammation. Additionally, trimetazidine exerts antiatherosclerotic effects by inhibiting plaque formation and promoting its stability. Moreover, it regulates apoptosis and angiogenesis, fostering endothelial cell survival and neovascularization. Understanding trimetazidine's multifaceted mechanisms underscores its potential as a therapeutic agent for endothelial dysfunction and associated cardiovascular disorders, warranting further investigation for clinical translation.

Anti-inflammatory reprogramming of microglia cells by metabolic modulators to counteract neurodegeneration; a new role for Ranolazine

Microglia chronic activation is a hallmark of several neurodegenerative diseases, including the retinal ones, possibly contributing to their etiopathogenesis. However, some microglia sub-populations have anti-inflammatory and neuroprotective functions, thus making arduous deciphering the role of these cells in neurodegeneration. Since it has been proposed that functionally different microglia subsets also rely on different metabolic routes, we hypothesized that modulating microglia metabolism might be a tool to enhance their anti-inflammatory features. This would have a preventive and therapeutic potential in counteracting neurodegenerative diseases. For this purpose, we tested various molecules known to act on cell metabolism, and we revealed the anti-inflammatory effect of the FDA-approved piperazine derivative Ranolazine on microglia cells, while confirming the one of the flavonoids Quercetin and Naringenin, both in vitro and in vivo. We also demonstrated the synergistic anti-inflammatory effect of Quercetin and Idebenone, and the ability of Ranolazine, Quercetin and Naringenin to counteract the neurotoxic effect of LPS-activated microglia on 661W neuronal cells. Overall, these data suggest that using the selected molecules -also in combination therapies- might represent a valuable approach to reduce inflammation and neurodegeneration while avoiding long term side effects of corticosteroids.

The Impact of Trimetazidine on Cardiac Fibrosis, Inflammation, and Function in Ischemic Cardiomyopathy Patients

BACKGROUND

Previous studies have shown that Trimetazidine (TMZ) improves vascular endothelial function and reduces the inflammatory process progression. However, limited data have been available regarding its effects on myocardial fibrosis following ischemia and causing left ventricular dysfunction.

PURPOSE

To investigate the impact of TMZ adjuvant therapy for ischemic cardiomyopathy (ICM) on cardiac fibrosis, vascular endothelial function, inflammation, and myocardial functions.

METHODS

This randomized, double-blind controlled clinical trial included 48 patients (aged 59.4 ± 9 years) with ICM who were randomly assigned to two groups: TMZ 35 mg twice daily and placebo in addition to conventional ICM medications. All patients received the tablets for 3 months. Both groups were then compared in terms of connective tissue growth factor (CTGF), endothelin-1 (ET-1), tumor necrosis factor-alpha (TNF-α), and some echocardiographic indices, weekly angina attacks and nitrate consumption before and after treatment.

RESULTS

No significant differences between CTGF, ET-1, and TNF-α levels, in addition to some echocardiographic indices, were observed between both groups before treatment. After treatment, the TMZ group had significantly lower ET-1 than the placebo group, with both groups exhibiting a substantial decrease in TNF-α and CTGF. The TMZ group had lower mean ± SD levels for TNF-α and CTGF and showed significant improvement in echocardiographic indices and weekly angina attacks after treatment.

CONCLUSION

Adjunctive TMZ therapy for ICM effectively improved vascular endothelial function and reduced inflammation. Furthermore, our exploratory findings may be used to provide new information on the potential effects of TMZ on myocardial fibrosis by downregulating CTGF.

Metabolic Approaches for the Treatment of Dilated Cardiomyopathy

In dilated cardiomyopathy (DCM), where the heart muscle becomes stretched and thin, heart failure (HF) occurs, and the cardiomyocytes suffer from an energetic inefficiency caused by an abnormal cardiac metabolism. Although underappreciated as a potential therapeutic target, the optimal metabolic milieu of a failing heart is still largely unknown and subject to debate. Because glucose naturally has a lower P/O ratio (the ATP yield per oxygen atom), the previous studies using this strategy to increase glucose oxidation have produced some intriguing findings. In reality, the vast majority of small-scale pilot trials using trimetazidine, ranolazine, perhexiline, and etomoxir have demonstrated enhanced left ventricular (LV) function and, in some circumstances, myocardial energetics in chronic ischemic and non-ischemic HF with a reduced ejection fraction (EF). However, for unidentified reasons, none of these drugs has ever been tested in a clinical trial of sufficient size. Other pilot studies came to the conclusion that because the heart in severe dilated cardiomyopathy appears to be metabolically flexible and not limited by oxygen, the current rationale for increasing glucose oxidation as a therapeutic target is contradicted and increasing fatty acid oxidation is supported. As a result, treating metabolic dysfunction in HF may benefit from raising ketone body levels. Interestingly, treatment with sodium-glucose cotransporter-2 inhibitors (SGLT2i) improves cardiac function and outcomes in HF patients with or without type 2 diabetes mellitus (T2DM) through a variety of pleiotropic effects, such as elevated ketone body levels. The improvement in overall cardiac function seen in patients receiving SGLT2i could be explained by this increase, which appears to be a reflection of an adaptive process that optimizes cardiac energy metabolism. This review aims to identify the best metabolic therapeutic approach for DCM patients, to examine the drugs that directly affect cardiac metabolism, and to outline all the potential ancillary metabolic effects of the guideline-directed medical therapy. In addition, a special focus is placed on SGLT2i, which were first studied and prescribed to diabetic patients before being successfully incorporated into the pharmacological arsenal for HF patients.

Trimetazidine, a metabolic modulator, attenuates silica-induced pulmonary fibrosis and decreases lactate levels and LDH activity in rats

Pulmonary fibrosis has been recently linked to metabolic dysregulation. Silica-induced pulmonary fibrosis in rats was employed by the current study to explore the effects of trimetazidine (a metabolic modulator-antianginal drug; TMZ) on silica-induced pulmonary fibrosis. Pulmonary fibrosis was induced by intranasal instillation of silica (50 mg/100 µl/rat) in TMZ versus vehicle-treated rats. Body weights of rats, weights of lungs, and wet-to-dry lung weights were determined. Various parameters were also measured in serum, bronchoalveolar lavage fluid (BALF) in addition to lung tissue homogenates. Moreover, histopathological examination of sectioned lungs for lesion score and distribution and histochemical detection of myeloperoxidase (MPO) in lung tissues were also performed. No significant differences were observed in body weight gains, lung coefficients, lung weights, and wet-to-dry lung weight in silica versus control rats. Elevated lactate levels in serum and lung homogenates were significantly attenuated by TMZ. In addition, lactate dehydrogenase activity, transforming growth factor-β, and total proteins in BALF were significantly normalized with TMZ. Moreover, TMZ significantly increased reduced glutathione and adenosine triphosphate levels and decreased nitrate/nitrite and hydroxyproline content in lungs of silica-treated rats. Histopathological examination of lungs revealed more than 56% reduction in lesion score and distribution by TMZ. MPO expression in lungs of silica-treated rats was also significantly attenuated by TMZ. TMZ attenuates silica-induced pulmonary fibrosis, an effect that could be mediated by suppressing anaerobic glycolysis-induced excessive lactate production. Regulation of oxidative stress could also play a role in TMZ-promoted protective effects.

Heart Failure and Drug Therapies: A Metabolic Review

Cardiovascular disease is the leading cause of mortality globally with at least 26 million people worldwide living with heart failure (HF). Metabolism has been an active area of investigation in the setting of HF since the heart demands a high rate of ATP turnover to maintain homeostasis. With the advent of -omic technologies, specifically metabolomics and lipidomics, HF pathologies have been better characterized with unbiased and holistic approaches. These techniques have identified novel pathways in our understanding of progression of HF and potential points of intervention. Furthermore, sodium-glucose transport protein 2 inhibitors, a drug that has changed the dogma of HF treatment, has one of the strongest types of evidence for a potential metabolic mechanism of action. This review will highlight cardiac metabolism in both the healthy and failing heart and then discuss the metabolic effects of heart failure drugs.

Trimetazidine and exercise offer analogous improvements to the skeletal muscle insulin resistance of mice through Nrf2 signaling

INTRODUCTION

Insulin resistance (IR) plays a key role in the pathogenesis and clinical course of patients with multiple metabolic diseases and diabetes. This study aimed to explore the effect of trimetazidine (TMZ) on skeletal muscle IR in mice fed a high-fat diet (HFD) and explore the possible underlying mechanism.

RESEARCH DESIGN AND METHODS

In vivo, a HFD mouse IR model was adopted and TMZ and exercise were used to intervene. Postintervention the following were determined: blood levels of glucose and insulin, homeostasis model assessment of IR index, expression of skeletal muscle insulin signaling-related proteins phosphorylated insulin receptor substrate 1 (p-IRS1/IRS1) and phosphorylated protein kinase B (p-AKT/AKT), nuclear factor erythroid 2 related factor 2 (Nrf2) signaling pathway, and oxidative stress. In vitro, a palmitate-treated C2C12 myotube IR model was constructed. Cellular glucose uptake, p-IRS1/IRS1, and p-AKT/AKT were determined, and reactive oxygen species (ROS) production was analyzed based on treatments with specific small interfering RNA of Nrf2 with or without TMZ. Western blot was used to obtain the protein expression level and ROS production by functional analysis kits.

RESULTS

In vivo, TMZ and exercise decreased the blood glucose and insulin levels and homeostasis model assessment of IR index, increased skeletal muscle insulin signaling-related protein ratios of p-IRS1/IRS1 and p-AKT/AKT, and both interventions activated Nrf2 signaling and reduced oxidative stress production in HFD mice. In vitro, TMZ reduced the oxidative stress reaction, increased the ratios of p-AKT/AKT and p-IRS1/IRS1, and attenuated the insulin stimulation of PA-induced glucose uptake. However, in the absence of Nrf2, TMZ failed to resist the effects of IR.

CONCLUSIONS

This study showed that TMZ, like exercise, brought about marked improvements to HFD-induced skeletal muscle IR through TMZ, a common pathway with exercise in the form of Nrf2, regulating oxidative stress. We provide new evidence to support the use of TMZ for diabetes treatment.

Newly discovered molecules associated with trimetazidine on improvement of skeletal muscle function in aging: evidence from myoblasts and mice

Poor muscle function is increasingly obvious with aging and needs effective and safe medicine for treatment. Trimetazidine (TMZ) has potential benefits for the condition but has not yet been fully recognized. In the randomized-control pilot study part, fifty-three old patients were assigned to the TMZ group or control group. For the TMZ group, a dose of 35 mg of oral TMZ was administered with a meal twice a day for 3 months. Only conventional treatments were administrated in the control group. Muscle strength, gait speed, muscle endurance, and balance maintenance were measured during the visits. In the experiments part, thirty mice were screened and randomly assigned to three groups: model group received a D-gal (500 mg/kg) intraperitoneal injection every two days for six weeks, the control group received saline at the same condition, and the intervention group received 5 mg/kg TMZ solution every two days by gavage for two weeks. Swimming tests and forelimb grip strength measurements were also performed. Furthermore, significantly clustered profiles from differentially expressed genes were found by RNA-seq and verified by qRT-PCR and WB. Myofiber analyses were done by H&E staining. Here, we found the improvement of skeletal performance in aged individuals and aged mouse. The dominant handgrip strength (HS) was increased by 24.4% and dominant pinch strength (PS) by 12.4% in participants with TMZ modified-release tablets consumption. Exhaustive time was increased by 23.6% and upper limb grip strength by 44.1% in aged mouse with TMZ-treated. Besides, we also identified some newly discovered molecules associated with TMZ on muscle function improvement during aging. To aged C2C12 cells and aged mouse muscle, TMZ-treated was related to a statistically significant decrease in the expressions of NOS3 and MMP-9, but a statistically significant increase in the expressions of OMD and MyoG. In summary, TMZ modified-release tablets can improve the muscle strength of elderly patients. Besides, the improvement of skeletal muscle function affected by TMZ was associated with reducing NOS3 expression in senescent myoblasts.

Trimetazidine Increases Plasma MicroRNA-24 and MicroRNA-126 Levels and Improves Dyslipidemia, Inflammation and Hypotension in Diabetic Rats

Trimetazidine (TMZ) improves endothelial dysfunction. However, its beneficial effect on endothelial miRNAs is unexplored in diabetes. The aim of the present study was to evaluate the effects of TMZ on plasma miRNA-24 and miRNA-126, dyslipidemia, inflammation, and blood pressure in the diabetic rats. Adult male Sprague-Dawley rats were randomly assigned into four groups (250 ± 20 g, n = 8): a control (C), an untreated diabetic (D), a diabetic group administrated with TMZ at 10 mg/kg (T10), and a diabetic group administrated with TMZ at 30 mg/kg (T30) for eight weeks. Diabetes was induced by injection of alloxan (120 mg/kg). The plasma levels of miR-24, miR-126, lipid profile, malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), blood glucose, body weight and systolic blood pressure were measured. The diabetic rats showed decreased plasma miR-24, HDL-c (P < 0.05), miR-126 (P < 0.01), body weight changes percent, body weight, and systolic blood pressure (P < 0.001) and increased triglycerides (TG), VLDL-c (P < 0.05), TNF-α, total cholesterol (TC) (P < 0.01) glucose, MDA and IL-6 (P < 0.001). Interestingly, all these changes were significantly improved by TMZ treatment. Our findings propose that TMZ has protective effects on decreased plasma miR-24 and miR-126 levels, inflammation, dyslipidemia and hypotension, and it may participate in endothelial dysfunction and atherosclerosis.

Trimetazidine in angina and poor muscle function: protocol for a randomized controlled study

BACKGROUND

Low handgrip strength (HS) and declining gait speed (GS) are increasingly obvious with aging, requiring effective, and safe medication for treatment. Trimetazidine (TMZ) modified release tablets, a common anti-angina drug, has potential benefits for alleviating the condition, but this has not yet been fully studied and therefore is the aim of this study.

METHODS

This is a prospective randomized controlled study. Fifty-eight eligible patients will be randomly assigned to one of two study groups: TMZ group or control group. For the TMZ group, a dose of 35 mg of oral TMZ will be administered with a meal twice a day for 3 months, in addition to any conventional treatments for angina. Only conventional treatments for angina will be administrated in the control group. The primary outcome will be the 6-min walking distance and the secondary outcomes will be: muscle strength (HS and pinch strength), GS, muscle endurance (five times sit-to-stand test), balance maintenance (tandem standing test), and the frequency of angina per week. Additionally, body mass index, circumferences (biceps, waist, hip, and calf), albumin levels, and the score on a five-question scale for sarcopenia will be obtained during the study.

DISCUSSION

This study aims to evaluate the usefulness of TMZ in a population with poor muscle function. The results may provide an effective and safe medical treatment to people with low muscle strength or physical performance.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR1800015000; www.chictr.org.cn/showproj.aspx?proj=25445.

Trimetazidine Attenuates Cardiac Dysfunction in Endotoxemia and Sepsis by Promoting Neutrophil Migration

Aims: Cardiac dysfunction can be a fatal complication during severe sepsis. The migration of neutrophils is significantly impaired during severe sepsis. We sought to determine the role of trimetazidine (TMZ) in regulation of neutrophil migration to the heart in a mouse model of sepsis and endotoxemia, and to identify the mechanism whereby TMZ confers a survival advantage.

Methods and Results: C57/BL6 mice were (1) injected with LPS followed by 24-h TMZ administration, or (2) treated with TMZ (20 mg/kg/day) for 1 week post cecal ligation and puncture (CLP) operation. Echocardiography and Millar system detection showed that TMZ alleviated cardiac dysfunction and histological staining showed the failure of neutrophils migration to heart in both LPS- and CLP-induced mice. Bone marrow transplantation revealed that TMZ-pretreated bone marrow cells improved LPS- and CLP-induced myocardial dysfunction and enhanced neutrophil recruitment in heart. In CXCL2-mediated chemotaxis assays, TMZ increased neutrophils migration via AMPK/Nrf2-dependent up-regulation of CXCR2 and inhibition of GRK2. Furthermore, using luciferase reporter gene and chromatin immunoprecipitation assays, we found that TMZ promoted the binding of the Nrf2 and CXCR2 promoter regions directly. Application of CXCR2 inhibitor completely reversed the protective effects of TMZ in vivo. Co-culture of neutrophils and cardiomyocytes further validated that TMZ decreased LPS-induced cardiomyocyte pyroptosis by targeting neutrophils.

Conclusion: Our findings suggested TMZ as a potential therapeutic agent for septic or endotoxemia associated cardiac dysfunction in mice.

STUDY HIGHLIGHTS 

What is the current knowledge on the topic?

Migration of neutrophils is significantly impaired during severe sepsis, but the underlying mechanisms remain unknown.

What question did this study address?

The effects of TMZ on cardiac dysfunction via neutrophils migration.

What this study adds to our knowledge

TMZ attenuated LPS-induced cardiomyocyte pyroptosis and cardiac dysfunction by promoting neutrophils recruitment to the heart tissues via CXCR2.

How this might change clinical pharmacology or translational science

Our findings suggested TMZ as a potential therapeutic agent for septic cardiac dysfunction.

Effectiveness and safety of anti-ischemic trimetazidine in patients with stable angina pectoris and Type 2 diabetes

Aim & methods: This 6-month prospective, observational, noninterventional, open-label clinical study assessed the effectiveness/safety of trimetazidine in 737 patients with stable angina pectoris and Type 2 diabetes mellitus (OGYI/51534–1/2014). Results: Trimetazidine-based therapy was effective in stable coronary artery disease, with significant improvements from baseline (p < 0.05) in: number of angina attacks/week (2.9 ± 2.4 vs 1.1 ± 1.6), angina severity (Canadian Cardiovascular Society Classification 1.9 ± 0.8 vs 1.2 ± 0.8), exercise capacity (metabolic equivalents 6.1 ± 1.7 vs 6.5 ± 1.7), and exercise-induced myocardial ischemia (min 5.5 ± 2.5 vs 6.5 ± 2.6). Discussion: Trimetazidine treatment significantly (p < 0.05) improved glucose metabolism, lowered HbA1c (7.1 ± 1.1% vs 6.6 ± 1.0%), glucose levels (7.7 ± 2.1 mmol/l vs 6.9 ± 1.6 mmol/l) and decreased arterial stiffness (pulse wave velocity 11.2 ± 2.1 m/s vs 10.4 ± 2.2 m/s). In most patients, the tolerability of trimetazidine was rated as excellent to good, with a low incidence of adverse events.

Trimetazidine therapy for diabetic mouse hearts subjected to ex vivo acute heart failure

Acute heart failure (AHF) is the most common primary diagnosis for hospitalized heart diseases in Africa. As increased fatty acid β-oxidation (FAO) during heart failure triggers detrimental effects on the myocardium, we hypothesized that trimetazidine (TMZ) (partial FAO inhibitor) offers cardioprotection under normal and obese-related diabetic conditions. Hearts were isolated from 12-14-week-old obese male and female diabetic (db/db) mice versus lean non-diabetic littermates (db/+) controls. The Langendorff retrograde isolated heart perfusion system was employed to establish an ex vivo AHF model: a) Stabilization phase-Krebs Henseleit buffer (10 mM glucose) at 100 mmHg (25 min); b) Critical Acute Heart Failure (CAHF) phase-(1.2 mM palmitic acid, 2.5 mM glucose) at 20 mmHg (25 min); and c) Recovery Acute Heart Failure phase (RAHF)-(1.2 mM palmitic acid, 10 mM glucose) at 100 mmHg (25 min). Treated groups received 5 μM TMZ in the perfusate during either the CAHF or RAHF stage for the full duration of each respective phase. Both lean and obese males benefited from TMZ treatment administered during the RAHF phase. Sex differences were observed only in lean groups where the phases of the estrous cycle influenced therapy; only the lean follicular female group responded to TMZ treatment during the CAHF phase. Lean luteal females rather displayed an inherent cardioprotection (without treatments) that was lost with obesity. However, TMZ treatment initiated during RAHF was beneficial for obese luteal females. TMZ treatment triggered significant recovery for male and obese female hearts when administered during RAHF. There were no differences between lean and obese male hearts, while lean females displayed a functional recovery advantage over lean males. Thus TMZ emerges as a worthy therapeutic target to consider for AHF treatment in normal and obese-diabetic individuals (for both sexes), but only when administered during the recovery phase and not during the very acute stages.

The effect of trimetazidine treatment in patients with type 2 diabetes undergoing percutaneous coronary intervention for AMI

PURPOSE

Trimetazidine (TMZ) improves clinical outcomes in patients with chronic heart failure and stable coronary artery disease. No study has yet evaluated the efficacy of TMZ in type 2 diabetes patients with acute myocardial infarction (AMI) undergoing Percutaneous Coronary Intervention (PCI). We performed this study to evaluate the efficacy TMZ in DM patients with AMI undergoing PCI, such as the effect on reductions in myocardial enzyme, improvements in liver function, modulation of glucose levels, and improvement in cardiac function.

METHODS

For this randomized study, we enrolled 173 AMI patients with type 2 diabetes undergoing PCI between January 1, 2014, and January 1, 2016. All patients received aspirin and ticagrelor upon admission and throughout their hospitalization. Patients in the experimental group were treated with a loading dose of 60mg TMZ at admission, and 20 mg TMZ three times a day thereafter. 89 patients were included in experimental group, and 84 patients were included in control group. All patients received PCI treatments. The endpoints evaluated were serum creatine kinase and its isoenzyme (CK and CK-MB), cardiac troponin I (cTNI), serum creatinine (Cr), serum urea, blood glucose, serum glutamic pyruvic transaminase (ALT), serum glutamic oxaloacetictransaminase (AST), left atrial dimension (LA), left ventricular ejection fraction (LVEF), left ventricular end-diastolic dimension (LVEDD), and cardiac output (CO).

FINDINGS

Compared with the control group, TMZ treatment significantly reduced CK and CK-MB on the second day in hospital ([797±582] vs. [1092±1114]; [80±60] vs. [105±100]; p=0.029, p=0.041, respectively), and cTNI after one and six days in hospital ([13.5±12.7] vs. [19.8±19.2]; [3.3±3.2] vs. [4.8±4.7]; two-tailed p=0.012). In addition, TMZ significantly lowered liver enzymes (ALT, AST) at 6days ([29.0±11.6] vs. [42.4±24.5]; [39.8±17.3] vs. [69.2±70.0]; two-tailed p=0.000), lowered glucose after 6days ([6.80±2.12] vs. [7.59±2.24]; p=0.019), and increased LVEF after ten to fourteen days ([58.4±8.6] vs. [54.9±8.4]; p=0.008). There were no significant effect on Cr and serum urea (p=0.988, p=0.569, respectively), nor on LA, LVEDD, and CO ([36.3±4.5] vs. [37.0±4.1], p=0.264; [52.0±4.9] vs. [53.1±4.6], p=0.128; [5.4±0.9] vs. [5.4±0.9], p=0.929, respectively).

IMPLICATIONS

Among type 2 diabetic patients with AMI undergoing PCI, TMZ significantly reduces serum myocardial enzyme, improves liver function, adjusts blood glucose and improves cardiac function.

Improvement of skeletal muscle performance in ageing by the metabolic modulator Trimetazidine

BACKGROUND

The loss of muscle mass (sarcopenia) and the associated reduced muscle strength are key limiting factors for elderly people's quality of life. Improving muscle performance does not necessarily correlate with increasing muscle mass. In fact, particularly in the elderly, the main explanation for muscle weakness is a reduction of muscle quality rather than a loss of muscle mass, and the main goal to be achieved is to increase muscle strength. The effectiveness of Trimetazidine (TMZ) in preventing muscle functional impairment during ageing was assessed in our laboratory.

METHODS

Aged mice received TMZ or vehicle for 12 consecutive days. Muscle function was evaluated at the end of the treatment by a grip test as well as by an inverted screen test at 0, 5, 7 and 12 days of TMZ treatment. After sacrifice, muscles were stored for myofiber cross-sectional area assessment and myosin heavy chain expression evaluation by western blotting.

RESULTS

Chronic TMZ treatment does not affect the mass of both gastrocnemius and tibialis anterior muscles, while it significantly increases muscle strength. Indeed, both latency to fall and grip force are markedly enhanced in TMZ-treated versus untreated mice. In addition, TMZ administration results in higher expression of slow myosin heavy chain isoform and increased number of small-sized myofibers.

CONCLUSIONS

We report here some data showing that the modulation of skeletal muscle metabolism by TMZ increases muscle strength in aged mice. Reprogramming metabolism might therefore be a strategy worth to be further investigated in view of improving muscle performance in the elderly.

Non-haemodynamic anti-anginal agents in the management of patients with stable coronary artery disease and diabetes: A review of the evidence

Patients with coronary artery disease and concomitant diabetes mellitus tend to have more extensive vessel disease than non-diabetes mellitus coronary artery disease patients, are at high risk of adverse cardiovascular events and suffer from a great anginal burden. Very few trials have specifically addressed the issue of optimal anti-anginal therapy in coronary artery disease patients who also have diabetes mellitus. Among 'classical' anti-anginal agents, recent guidelines do not specifically recommend any molecule over others; however, European Society of Cardiology guidelines acknowledge that favourable data in patients with concomitant diabetes mellitus and coronary artery disease are available for trimetazidine and ranolazine, two anti-anginal agents with a non-haemodynamic mechanism of action. The aim of this article is to review available evidence supporting the anti-anginal efficacy of these two drugs in the difficult-to-treat population of diabetes mellitus patients, including their effects on glycated haemoglobin (HbA1c), a measure of medium-term glycaemic control. Although direct head-to-head comparisons have not been performed, available evidence favours ranolazine as an effective anti-anginal agent over trimetazidine in this population. In addition, ranolazine lowers HbA1c, indicating that it may improve glycaemic control in patients with diabetes mellitus. Conversely, scanty data are available on the metabolic effects of trimetazidine in this cohort of patients. Thus, ranolazine may represent a valuable therapeutic option in stable coronary artery disease patients with diabetes mellitus.

Deranged Cardiac Metabolism and the Pathogenesis of Heart Failure

Activation of the neuro-hormonal system is a pathophysiological consequence of heart failure. Neuro-hormonal activation promotes metabolic changes, such as insulin resistance, and determines an increased use of non-carbohydrate substrates for energy production. Fasting blood ketone bodies as well as fat oxidation are increased in patients with heart failure, yielding a state of metabolic inefficiency. The net result is additional depletion of myocardial adenosine triphosphate, phosphocreatine and creatine kinase levels with further decreased efficiency of mechanical work. In this context, manipulation of cardiac energy metabolism by modification of substrate use by the failing heart has produced positive clinical results. The results of current research support the concept that shifting the energy substrate preference away from fatty acid metabolism and towards glucose metabolism could be an effective adjunctive treatment in patients with heart failure. The additional use of drugs able to partially inhibit fatty acids oxidation in patients with heart failure may therefore yield a significant protective effect for clinical symptoms and cardiac function improvement, and simultaneously ameliorate left ventricular remodelling. Certainly, to clarify the exact therapeutic role of metabolic therapy in heart failure, a large multicentre, randomised controlled trial should be performed.

Metabolic Therapy in Heart Failure

Metabolic impairments play an important role in the development and progression of heart failure. The use of metabolic modulators, the number of which is steadily increasing, may be particularly effective in the treatment of heart failure. Recent evidence suggests that modulating cardiac energy metabolism by reducing fatty acid oxidation and/or increasing glucose oxidation represents a promising approach to the treatment of patients with heart failure. This review focuses on the role of metabolic modulators, in particular trimetazidine, as a potential additional medication to conventional medical therapy in heart failure.

Diabetic cardiac autonomic neuropathy: Do we have any treatment perspectives?

Cardiac autonomic neuropathy (CAN) is a serious and common complication of diabetes mellitus (DM). Despite its relationship to an increased risk of cardiovascular mortality and its association with multiple symptoms and impairments, the significance of CAN has not been fully appreciated. CAN among DM patients is characterized review the latest evidence and own data regarding the treatment and the treatment perspectives for diabetic CAN. Lifestyle modification, intensive glycemic control might prevent development or progression of CAN. Pathogenetic treatment of CAN includes: balanced diet and physical activity; optimization of glycemic control; treatment of dyslipoproteinemia; correction of metabolic abnormalities in myocardium; prevention and treatment of thrombosis; use of aldose reductase inhibitors; dihomo-γ-linolenic acid (DGLA), acetyl-L-carnitine, antioxidants, first of all α-lipoic acid (α-LA), use of long-chain ω-3 and ω-6 polyunsaturated fatty acids (ω-3 and ω-6 PUFAs), vasodilators, fat-soluble vitamin B₁, aminoguanidine; substitutive therapy of growth factors, in severe cases-treatment of orthostatic hypotension. The promising methods include research and use of tools that increase blood flow through the vasa vasorum, including prostacyclin analogues, thromboxane A₂ blockers and drugs that contribute into strengthening and/or normalization of Na⁺, K⁺-ATPase (phosphodiesterase inhibitor), α-LA, DGLA, ω-3 PUFAs, and the simultaneous prescription of α-LA, ω-3 PUFA and DGLA.

Carbohydrate metabolism parameters in angina patients treated with metoprolol and its combination with trimetazidine

Aim. To study the effects of a β-adrenoblocker (β-AB) metoprolol (Mp) and its combination with trimetazidine (Tmd) on glucose tolerance and insulin sensitivity in patients with angina pectoris. Material and methods. In total, 28 men aged 46-68 years, with Functional Class (FC) II-III stable angina, positive exercise stress test (EST), and no prior β-AB therapy were examined. Individual Mp doses were selected based on the paired EST results. For one month, the Mp dose of 50 or 100 mg/d was administered twice a day; for the next month, participants received Mp and Tmd (70 mg/d). A standard glucose tolerance test (GTT) was performed at baseline and at the end of one-month periods of Mp or Mp + Tmd treatment. Carbohydrate metabolism disturbances were diagnosed according to the WHO criteria (1999). Insulin resistance (IR) was assessed by HOMA2-IR parameter, and tissue insulin sensitivity by ISI0,120 parameter. Results. After one month of Mp treatment, a decrease in fasting glucose levels was observed (p=0,025). At the same time, the GTT results demonstrated increased glucose levels 2 hours after glucose load, compared to baseline (p=0,049). Tissue insulin sensitivity (ISI0,120) showed some reduction (p=0,14), while the number of patients with impaired glucose tolerance (IGT) increased from 4 to 8 (p=0,006). The levels of fasting and post-load glycemia after one month of the combination therapy with Mp and Tmd were similar to those after the Mp treatment. Insulin levels at 2 hours after glucose load were higher than those observed after the Mp therapy (p=0,045). Compared to baseline, HOMA2-IR values increased, and IDI0,120 values decreased (p=0,036). The IDI0,120 dynamics suggested a reduction in insulin sensitivity for both treatment regimens. IGT was registered in 10 patients. Conclusion. In angina patients, impaired glucose control was observed as early as 1 month after the start of Mp treatment. This early impairment could be diagnosed by GTT. Although the combination therapy with Mp and Tmd did not prevent this impairment, but provided a greater antiischemic effect and, therefore, was clinically appropriate

Effect of trimetazidine treatment on the transient outward potassium current of the left ventricular myocytes of rats with streptozotocin-induced type 1 diabetes mellitus

Cardiovascular complications are a leading cause of mortality in patients with diabetes mellitus (DM). The present study was designed to investigate the effects of trimetazidine (TMZ), an anti-angina drug, on transient outward potassium current (I_to) remodeling in ventricular myocytes and the plasma contents of free fatty acid (FFA) and glucose in DM. Sprague-Dawley rats, 8 weeks old and weighing 200-250 g, were randomly divided into three groups of 20 animals each. The control group was injected with vehicle (1 mM citrate buffer), the DM group was injected with 65 mg/kg streptozotocin (STZ) for induction of type 1 DM, and the DM+TMZ group was injected with the same dose of STZ followed by a 4-week treatment with TMZ (60 mg·kg⁻¹·day⁻¹). All animals were then euthanized and their hearts excised and subjected to electrophysiological measurements or gene expression analyses. TMZ exposure significantly reversed the increased plasma FFA level in diabetic rats, but failed to change the plasma glucose level. The amplitude of I_to was significantly decreased in left ventricular myocytes from diabetic rats relative to control animals (6.25 ± 1.45 vs 20.72 ± 2.93 pA/pF at +40 mV). The DM-associated I_to reduction was attenuated by TMZ. Moreover, TMZ treatment reversed the increased expression of the channel-forming alpha subunit Kv1.4 and the decreased expression of Kv4.2 and Kv4.3 in diabetic rat hearts. These data demonstrate that TMZ can normalize, or partially normalize, the increased plasma FFA content, the reduced I_to of ventricular myocytes, and the altered expression Kv1.4, Kv4.2, and Kv4.3 in type 1 DM.

Insulin resistance, metabolic stress, and atherosclerosis

Atherosclerosis, a pathological process that underlies the development of cardiovascular disease, is the primary cause of morbidity and mortality in patients with type 2 diabetes mellitus (T2DM). T2DM is characterized by hyperglycemia and insulin resistance (IR), in which target tissues fail to respond to insulin. Systemic IR is associated with impaired insulin signaling in the metabolic tissues and vasculature. Insulin receptor is highly expressed in the liver, muscle, pancreas, and adipose tissue. It is also expressed in vascular cells. It has been suggested that insulin signaling in vascular cells regulates cell proliferation and vascular function. In this review, we discuss the association between IR, metabolic stress, and atherosclerosis with focus on 1) tissue and cell distribution of insulin receptor and its differential signaling transduction and 2) potential mechanism of insulin signaling impairment and its role in the development of atherosclerosis and vascular function in metabolic disorders including hyperglycemia, hypertension, dyslipidemia, and hyperhomocysteinemia. We propose that insulin signaling impairment is the foremost biochemical mechanism underlying increased cardiovascular morbidity and mortality in atherosclerosis, T2DM, and metabolic syndrome.

Human obesity is characterized by defective fat storage and enhanced muscle fatty acid oxidation, and trimetazidine gradually counteracts these abnormalities

An impaired ability to store fatty acids (FA) in subcutaneous adipose tissue (SAT) may be implicated in the pathogenesis of obesity-related diseases via overexposure of lean tissues and production of free radicals from FA oxidation (FAO). We studied regional FA metabolism in skeletal muscle and adipose tissue in humans and investigated the long-term effects of the FAO inhibitor trimetazidine on glucose and FA metabolism. Positron emission tomography (PET) and [(11)C]palmitate were used to compare FA metabolism in SAT and skeletal muscle between eight obese and eight nonobese subjects (BMI ≥/< 30 kg/m(2)). A subgroup of nine subjects underwent a 1-mo trimetazidine administration. PET with [(11)C]palmitate and [(18)F]fluorodeoxyglucose, indirect calorimetry, and MRI before and after this period were performed to characterize glucose and FA metabolism, fat masses, skeletal muscle triglyceride, and creatine contents. Obesity was characterized by a 100% elevation in FAO and a defect in the FA esterification rate constant (P < 0.05) in skeletal muscle. FA esterification was reduced by ~70% in SAT (P < 0.001) in obese vs. control subjects. The degrees of obesity and insulin resistance were both negatively associated with esterification-related parameters and positively with FAO (P < 0.05). Trimetazidine increased skeletal muscle FA esterification (P < 0.01) and mildly upregulated glucose phosphorylation (P = 0.066). Our data suggest that human obesity is characterized by a defect in tissue FA storage capability, which is accompanied by a (potentially compensatory) elevation in skeletal muscle FAO; trimetazidine diverted FA from oxidative to nonoxidative pathways and provoked an initial activation of glucose metabolism in skeletal muscle.

Trimetazidine Shortens QTc Interval in Patients With Ischemic Heart Failure

Background: Trimetazidine improves functional class and left ventricular function in patients with heart failure; however, its potential impact on QTc interval remains undefined. We analyzed the effects of trimetazidine on QTc interval in patients with ischemic heart failure. Methods: A prospective trial included 42 patients with ischemic heart failure (New York Heart Association [NYHA] 2 or 3) and reduced left ventricular ejection fraction (<55%), who were randomly allocated to conventional therapy plus trimetazidine in a modulated release formulation (35 mg twice daily; 22 patients) or conventional therapy alone (20 patients; controls). We measured QTc interval at baseline and after 1 month. Results: At baseline, QTc interval duration was similar in both groups (443 ± 41 milliseconds in trimetazidine group vs 446 ± 27 milliseconds in controls, P = .62). After 1 month, QTc interval decreased in the trimetazidine group (404 ± 36 milliseconds, P = .0002) but not in controls (452 ± 25 milliseconds, P = .74). QTc interval shortening with trimetazidine was more pronounced in patients with prolonged (>440 milliseconds) baseline QTc interval (—45 ± 38 milliseconds) than in patients with normal QTc interval (—19 ± 19 milliseconds P = .04). Significant QTc interval shortening (>20 milliseconds) was present in 14 of 22 patients (64%) in trimetazidine group compared to 3 of 20 (15%) patients in control group (P = .002). Conclusions: Trimetazidine therapy is associated with QTc interval shortening in patients with ischemic heart failure.

Diabetic myocardial disease: pathophysiology, early diagnosis and therapeutic options

Diabetes mellitus is a powerful risk factor for cardiovascular disease associated with high morbidity and mortality rates. Diabetic patients also have an increased incidence of heart failure which has been traditionally attributed to the concurrent presence of ischemic or hypertensive heart disease. Yet, nowadays, according to recent scientific evidence, diabetic myocardial disease (DMD) is more and more being considered as a distinct nosologic entity, independent of the co-existence of coronary artery disease, arterial hypertension or other risk factors, with the potential to lead to a self-existent progressive development of heart failure. In this article, we review the possible pathophysiologic mechanisms involved in the development of DMD as well as the structural and functional changes in the diabetic heart. We emphasize the importance of early detection of the syndrome, especially by novel echocardiographic techniques. Finally, we refer to the various therapeutic options for the optimal management of DMD according to the recent literature.

Effect of trimetazidine on quality of life in elderly patients with ischemic dilated cardiomyopathy

INTRODUCTION

Elderly patients have an increased incidence of ischemic dilated cardiomyopathy, often related to diffuse coronary artery disease. Data have been cumulated to suggest that trimetazidine improves myocardial ischemia in patients with ischemic heart disease and improves left ventricular function in elderly patients with ischemic cardiomyopathy. The purpose of the present study was to assess the effects of trimetazidine in addition to standard cardiovascular therapy on left ventricular function and quality of life (QOL) parameters in elderly patients with ischemic heart disease and reduced left ventricular function.

METHODS

Patients were randomized to receive either trimetazidine (twice daily) or placebo (twice daily) in addition to standard therapy, and were evaluated at baseline and after 6 months.

RESULTS

Forty-seven patients completed the study (40 male, seven female; mean [+/-SD] age 78+/-3.4 years). Demographic data were comparable between the two groups with respect to sex, age, and race. At 6 months there was a significant improvement in the number of angina episodes per week in the trimetazidine group (-2.3+/-1, P=0.023). The overall assessment of QOL by a visual analog scale showed an improvement in patients randomized to trimetazidine at 6 months (from 4.1+/-0.6 to 6.4+/-0.8, P<0.01) and no changes in patients randomized to placebo (from 4.3+/-0.7 to 4.2+/-0.9, P>0.05). Physical QOL, evaluated by a MacNew Quality of Life After Myocardial Infarction questionnaire (MacNewQLMI), improved in patients randomized to trimetazidine but not in those allocated to placebo (32%+/-5% vs. -1%+/-3%, P<0.01). Similar results were obtained on social QOL evaluated by MacNewQLMI with trimetazidine compared with placebo (39%+/-4% vs. -2%+/-5%, P<0.01).

CONCLUSION

In elderly patients with ischemic heart disease and reduced ventricular function, trimetazidine improves clinical condition and QOL.

Trimetazidine, a Metabolic Modulator, Has Cardiac and Extracardiac Benefits in Idiopathic Dilated Cardiomyopathy

Background— The anti-ischemic agent trimetazidine improves ejection fraction in heart failure that is hypothetically linked to inhibitory effects on cardiac free fatty acid (FFA) oxidation. However, FFA oxidation remains unmeasured in humans. We investigated the effects of trimetazidine on cardiac perfusion, efficiency of work, and FFA oxidation in idiopathic dilated cardiomyopathy.

Methods and Results— Nineteen nondiabetic patients with idiopathic dilated cardiomyopathy on standard medication were randomized to single-blind trimetazidine (n=12) or placebo (n=7) for 3 months. Myocardial perfusion, FFA, and total oxidative metabolism were measured using positron emission tomography with [ 15 O]H 2 O, [ 11 C]acetate, and [ 11 C]palmitate. Cardiac function was assessed echocardiographically; insulin sensitivity was assessed by the homeostasis model assessment index. Trimetazidine increased ejection fraction from 30.9±8.5% to 34.8±12% ( P =0.027 versus placebo). Myocardial FFA uptake was unchanged, and β-oxidation rate constant decreased only 10%. Myocardial perfusion, oxidative metabolism, and work efficiency remained unchanged. Trimetazidine decreased insulin resistance (glucose: 5.9±0.7 versus 5.5±0.6 mmol/L, P =0.047; insulin: 10±6.9 versus 7.6±3.6 mU/L, P =0.031; homeostasis model assessment index: 2.75±2.28 versus 1.89±1.06, P =0.027). The degree of β-blockade and trimetazidine interacted positively on ejection fraction. Plasma high-density lipoprotein concentrations increased 11% ( P <0.001).

Conclusions— In idiopathic dilated cardiomyopathy with heart failure, trimetazidine increased cardiac function and had both cardiac and extracardiac metabolic effects. Cardiac FFA oxidation modestly decreased and myocardial oxidative rate was unchanged, implying increased oxidation of glucose. Trimetazidine improved whole-body insulin sensitivity and glucose control in these insulin-resistant idiopathic dilated cardiomyopathy patients, thus hypothetically countering the myocardial damage of insulin resistance. Additionally, the trimetazidine-induced increase in ejection fraction was associated with greater β1-adrenoceptor occupancy, suggesting a synergistic mechanism.

An integrated view of insulin resistance and endothelial dysfunction

Endothelial dysfunction and insulin resistance are frequently comorbid states. Vasodilator actions of insulin are mediated by phosphatidylinositol 3-kinase (PI3K)-dependent signaling pathways that stimulate production of nitric oxide from vascular endothelium. This helps to couple metabolic and hemodynamic homeostasis under healthy conditions. In pathologic states, shared causal factors, including glucotoxicity, lipotoxicity, and inflammation selectively impair PI3K-dependent insulin signaling pathways that contribute to reciprocal relationships between insulin resistance and endothelial dysfunction. This article discusses the implications of pathway-selective insulin resistance in vascular endothelium, interactions between endothelial dysfunction and insulin resistance, and therapeutic interventions that may simultaneously improve both metabolic and cardiovascular physiology in insulin-resistant conditions.

Myocardial fatty acid metabolism and cardiac performance in heart failure

It is well established that cardiac metabolism is abnormal in heart failure (HF). Experimental studies suggest that in severe HF, cardiac metabolism reverts to a more fetal-like substrate use characterized by enhanced glucose and downregulated free fatty acid (FFA) metabolism. Correspondingly, in humans, when FFA levels are similar, myocardial glucose metabolism is increased, and FFA metabolism is decreased. However, depression of left ventricular function and insulin resistance induces a shift back to greater FFA uptake and oxidation by increasing circulating FFA availability. Myocardial insulin resistance may further impair myocardial glucose uptake and lead to an energy depletion state. Experimental and preliminary clinical studies suggest that metabolic modulators enhancing myocardial glucose oxidation may improve cardiac function in patients with chronic HF. However, it has been found that acute FFA deprivation is harmful to the cardiac performance. Optimizing myocardial energy metabolism may serve as an additional approach for managing HF, but further studies are warranted.

Metabolic Mechanisms in Heart Failure

Although neurohumoral antagonism has successfully reduced heart failure morbidity and mortality, the residual disability and death rate remains unacceptably high. Though abnormalities of myocardial metabolism are associated with heart failure, recent data suggest that heart failure may itself promote metabolic changes such as insulin resistance, in part through neurohumoral activation. A detrimental self-perpetuating cycle (heart failure --> altered metabolism --> heart failure) that promotes the progression of heart failure may thus be postulated. Accordingly, we review the cellular mechanisms and pathophysiology of altered metabolism and insulin resistance in heart failure. It is hypothesized that the ensuing detrimental myocardial energetic perturbations result from neurohumoral activation, increased adverse free fatty acid metabolism, decreased protective glucose metabolism, and in some cases insulin resistance. The result is depletion of myocardial ATP, phosphocreatine, and creatine kinase with decreased efficiency of mechanical work. On the basis of the mechanisms outlined, appropriate therapies to mitigate aberrant metabolism include intense neurohumoral antagonism, limitation of diuretics, correction of hypokalemia, exercise, and diet. We also discuss more novel mechanistic-based therapies to ameliorate metabolism and insulin resistance in heart failure. For example, metabolic modulators may optimize myocardial substrate utilization to improve cardiac function and exercise performance beyond standard care. The ultimate success of metabolic-based therapy will be manifest by its capacity further to lessen the residual mortality in heart failure.

Insulin action and insulin resistance in vascular endothelium

PURPOSE OF REVIEW

Vasodilator actions of insulin are mediated by phosphatidylinositol 3-kinase dependent insulin signaling pathways in endothelium, which stimulate production of nitric oxide. Insulin-stimulated nitric oxide mediates capillary recruitment, vasodilation, increased blood flow, and subsequent augmentation of glucose disposal in skeletal muscle. Distinct mitogen-activated protein kinase dependent insulin signaling pathways regulate secretion of the vasoconstrictor endothelin-1 from endothelium. These vascular actions of insulin contribute to the coupling of metabolic and hemodynamic homeostasis that occurs under healthy conditions. Insulin resistance is characterized by pathway-specific impairment in phosphatidylinositol 3-kinase dependent signaling in both metabolic and vascular insulin target tissues. Here we discuss consequences of pathway-specific insulin resistance in endothelium and therapeutic interventions targeting this selective impairment.

RECENT FINDINGS

Shared causal factors such as glucotoxicity, lipotoxicity, and inflammation selectively impair phosphatidylinositol 3-kinase dependent insulin signaling pathways, creating reciprocal relationships between insulin resistance and endothelial dysfunction. Diet, exercise, cardiovascular drugs, and insulin sensitizers simultaneously modulate phosphatidylinositol 3-kinase and mitogen-activated protein kinase dependent pathways, improving metabolic and vascular actions of insulin.

SUMMARY

Pathway-specific impairment in insulin action contributes to reciprocal relationships between endothelial dysfunction and insulin resistance, fostering clustering of metabolic and cardiovascular diseases in insulin-resistant states. Therapeutic interventions that target this selective impairment often simultaneously improve both metabolic and vascular function.

Inhibition of free fatty acids metabolism as a therapeutic target in patients with heart failure

Recent studies have evidenced that alterations of cardiac metabolism can be present in several cardiac syndromes. In heart failure, wasting of subcutaneous fat and skeletal muscle is relatively common and suggests an increased utilisation of non-carbohydrate substrates for energy production. In fact, fasting blood ketone bodies as well as fat oxidation during exercise have been shown to be increased in patients with heart failure. This metabolic shift determines a reduction of myocardial oxygen consumption efficiency. A direct approach to manipulate cardiac energy metabolism consists in modifying substrate utilisation by the heart. To date, the most effective metabolic treatments include several pharmacological agents that directly inhibit fatty acid oxidation. Clinical studies have shown that these agents can substantially increase the ischaemic threshold in patients with effort angina. However, the results of current research is also supporting the concept that shifting the energy substrate preference away from fatty acid metabolism and towards glucose metabolism could be an effective adjunctive treatment in patients with heart failure, in terms of left ventricular function and glucose metabolism improvement. In fact, these agents have also been shown to improve overall glucose metabolism in diabetic patients with left ventricular dysfunction. In this paper, the recent literature on the beneficial therapeutic effects of modulation of cardiac metabolic substrates utilisation in patients with heart failure is reviewed and discussed.

Trimetazidine improves post-ischemic recovery by preserving endothelial nitric oxide synthase expression in isolated working rat hearts

OBJECTIVE

Previous investigations have consistently shown that the piperazine derivative trimetazidine (TMZ, 1-[2,3,4-trimethoxybenzil] piperazine, dihydrocloride) has cardioprotective effects in the experimental ischemia-reperfusion model. We tested the hypothesis that cardioprotective effect of TMZ is partly mediated by preservation of the endothelial barrier of the coronary microcirculation.

METHODS

Isolated Wistar rat (250-300 g) hearts were subjected to a 15 min period of global ischemia and 180 min reperfusion in the presence or absence of 1 microM TMZ. Hemodynamic parameters, heart weight, creatinekinase (CK) release and microvascular permeability (FITC-albumin extravasation) were evaluated. In addition, eNOS gene expression was estimated by rt-PCR, and eNOS protein levels were assessed by Western analysis. In order to confirm the involvement of NO in mediating the cardioprotective effects of TMZ, 30 microM N(omega)-nitro-l-arginine methylester (L-NAME), a specific inhibitor of nitric oxide synthase, was used.

RESULTS

After ischemia and reperfusion, TMZ produced a significant improvement of mechanical function associated with a reduction of CK release and FITC-albumin diffusion (P<0.001); the agent also resulted in improvement in coronary flow (at 45 min+27% vs control). The eNOS mRNA and protein levels were significantly higher in TMZ-treated hearts compared to controls. The addition of L-NAME significantly reduced the beneficial effects of TMZ on contractile function, CK release and FITC-albumin diffusion.

CONCLUSIONS

in the isolated rat heart, TMZ exerts a relevant, NO-dependent, cardioprotection against ischemia-reperfusion injury and preserves the endothelial barrier of the coronary circulation. This could contribute to explain the cardioprotective action of TMZ following ischemia and reperfusion.

Role of trimetazidine in management of ischemic cardiomyopathy

Despite treatment with conventional agents, a high proportion of patients with ischemic cardiomyopathy continue to have symptoms. Moreover, a substantial proportion shows progressive contractile dysfunction leading to left ventricular (LV) enlargement and heart failure. Therefore, a need exists for new treatments for ischemic cardiomyopathy that tackle mechanisms other than those already addressed by conventional agents. Emerging evidence suggests that in patients with ischemic cardiomyopathy, LV dysfunction develops as a result of alterations in substrate metabolism, which contribute to contractile dysfunction and the progression of LV remodeling. Trimetazidine, a novel pharmacologic agent that acts on myocardial metabolic pathways, appears to protect the heart from the deleterious effects of ischemia, and it has been shown to enhance LV contractility in patients with stunned or hibernating myocardium. This article reviews recent clinical trials that have assessed the therapeutic role of trimetazidine in patients with ischemic cardiomyopathy. Trimetazidine has been shown to improve symptoms and LV ejection fraction and to have a beneficial effect on the inflammatory profile and endothelial function in these patients. These results suggest that trimetazidine is a useful adjunct to our current armamentarium for the treatment of patients with ischemic cardiomyopathy.

Metabolic therapy for patients with diabetes mellitus and coronary artery disease

Patients with diabetes mellitus and ischemic heart disease more frequently develop heart failure and have a greater amount of myocardial ischemia, often silent, compared with patients without diabetes. Furthermore, patients with coronary artery disease (CAD) and diabetes or insulin resistance have altered myocardial metabolism and accelerated and diffuse atherogenesis with involvement of distal coronary segments that causes chronic hypoperfusion and hibernation. Therefore, in patients with diabetes and CAD, the ischemic metabolic changes are heightened by the metabolic changes in patients with diabetes. An important metabolic alteration in patients with diabetes is the increase in free fatty acid (FFA) concentrations and the increased skeletal muscle and myocardial FFA uptake and oxidation. The increased uptake and utilization of FFA and the reduced utilization of glucose as a source of energy during stress and ischemia contribute to the increased susceptibility of diabetic hearts to myocardial ischemia and to a greater decrease of myocardial performance for a given amount of ischemia compared with nondiabetic hearts. A therapeutic approach aimed at an improvement in cardiac metabolism through manipulations of the use of metabolic substrates should result in an improvement in myocardial ischemia and left ventricular (LV) function. The inhibition of FFA oxidation with trimetazidine improves cardiac metabolism at rest, increases cardiac resistance to ischemia, and therefore reduces the decrease of LV function caused by chronic hypoperfusion and repetitive episodes of myocardial ischemia in patients with and without diabetes. Thus, modulation of myocardial FFA metabolism should be the key target for metabolic interventions in patients with CAD with and without diabetes. In patients with diabetes, the effects of modulation of FFA metabolism should be even greater compared with those observed in patients without diabetes. Because of its effect on cardiac metabolism at rest and its effects on myocardial ischemia and LV function, trimetazidine should always be considered for the treatment of patients with diabetes with CAD with or without LV dysfunction.

A randomized clinical trial of trimetazidine, a partial free fatty acid oxidation inhibitor, in patients with heart failure

OBJECTIVES

This study sought to assess whether the long-term addition of trimetazidine to conventional treatment could improve functional class, exercise tolerance, and left ventricular function in patients with heart failure (HF).

BACKGROUND

Previous small studies have shown that trimetazidine may be beneficial in terms of left ventricular function preservation and control of symptoms in patients with post-ischemic HF.

METHODS

Fifty-five patients with HF were randomly allocated in an open-label fashion to either conventional therapy plus trimetazidine (20 mg three times daily) (28 patients) or conventional therapy alone (27 patients). Mean follow-up was 13 +/- 3 months. At study entry and at follow-up, all patients underwent exercise testing and two-dimensional echocardiography. Among the others, New York Heart Association (NYHA) functional class and ejection fraction (EF) were evaluated.

RESULTS

In the trimetazidine group, NYHA functional class significantly improved compared with the conventional therapy group (p < 0.0001). Treatment with trimetazidine significantly decreased left ventricular end-systolic volume (from 98 +/- 36 ml to 81 +/- 27 ml, p = 0.04) and increased EF from 36 +/- 7% to 43 +/- 10% (p = 0.002). On the contrary, in the conventional therapy group, both left ventricular end-diastolic and -systolic volumes increased from 142 +/- 43 ml to 156 +/- 63 ml, p = 0.2, and from 86 +/- 34 ml to 104 +/- 52 ml, p = 0.1, respectively; accordingly, EF significantly decreased from 38 +/- 7% to 34 +/- 7% (p = 0.02).

CONCLUSIONS

In conclusion, long-term trimetazidine improves functional class and left ventricular function in patients with HF. This benefit contrasts with the natural history of the disease, as shown by the decrease of EF in patients on standard HF therapy alone.