Trimetazidine reduces oxidative stress in cardiac surgery

Influence of trimetazidine on myocardial injury in mice with diabetic cardiomyopathy

INTRODUCTION

The prevalence of diabetes mellitus is increasing year by year globally, and diabetic cardiomyopathy (DCM), as the most common complication of type 2 diabetes mellitus, seriously affects the prognosis of patients. Trimetazidine (TMZ), as a drug affecting myocardial energy metabolism, mainly reduces the oxidation rate of β-oxidation by inhibiting 3-ketoacyl-CoA thiolase (3-KAT), a key enzyme in β-oxidation of free fatty acid (FFA), so that the energy metabolism substrate of cardiomyocytes preferentially selects glucose rather than fatty acids, increases the content of intracellular adenosine triphosphate (ATP), enhances the contractile function of cardiomyocytes, and improves the state of cellular ischemia and hypoxia. Previous studies have shown that TMZ is closely related to the activation and induction of apoptosis of the MAPK pathway and AMPK pathway, and plays a role in the treatment of diabetic cardiomyopathy, but the specific mechanism is still unclear.

OBJECTIVE

This study aims to investigate the impact of TMZ on myocardial damage in mice exhibiting diabetic cardiomyopathy (DCM), and to furnish a laboratory foundation for the clinical treatment of diabetic cardiomyopathy.

METHOD

Male db/db mice (6 weeks old, n = 21) and male wild-type (wt) (6 weeks old, n = 20) mice were selected for the study. The wt mice were randomly assigned to the wt group (n = 10) and wt + TMZ group (n = 10), while the remaining db/db mice were randomly allocated to the db/db group (n = 11) and db/db + TMZ group (n = 10). Following 8 weeks of feeding, the wt + TMZ group and db/db + TMZ group received TMZ via gavage, whereas the remaining groups were administered physiological saline. Periodic measurements of blood glucose, blood lipids, and myocardial enzymes were conducted in mice, with samples obtained after the 12th week for subsequent biochemical analysis, myocardial pathology assessment, immunohistochemistry, western blot analysis, and TUNEL staining (TdT-mediated dUTP Nick-End Labeling).

RESULT

GLU, TC, TG, LDL-C, and CK-MB levels were significantly higher in db/db mice compared to wt mice (GLU: M ± SD wt 5.94 ± 0.37, db/db 17.63 ± 0.89, p < 0.05, ES = 0.991; TC: M ± SD wt 3.01 ± 0.32, db/db 6.97 ± 0.36, p < 0.05, ES = 0.972; TG: M ± SD wt 0.58 ± 0.2, db/db 1.75 ± 0.14, p < 0.05, ES = 0.920; LDL-C: M ± SD wt 1.59 ± 0.12, db/db 3.87 ± 0.14, p < 0.05, ES = 0.989; CK-MB: M ± SD wt 0.12 ± 0.01, db/db 0.31 ± 0.04, p < 0.05, ES = 0.928). HDL-C levels were significantly lower in db/db mice (M ± SD wt 1.89 ± 0.08, db/db 0.64 ± 0.09, p < 0.05, ES = 0.963). Histopathological analysis confirmed myocardial damage in db/db mice. Treatment with TMZ reduced GLU, TC, TG, LDL-C, and CK-MB levels (p < 0.05, ES > 0.9) and increased HDL-C levels compared to untreated db/db mice. Additionally, TMZ treatment significantly decreased myocardial cell apoptosis (p < 0.05, ES = 0.980). These results demonstrate the efficacy of TMZ in reversing myocardial injury in DCM mice.

CONCLUSION

TMZ can mitigate myocardial damage in db/db mice by downregulating the expression of caspase-12, a protein associated with the endoplasmic reticulum stress (ERS) cell apoptosis pathway, consequently diminishing cell apoptosis. This underscores the protective efficacy of TMZ against myocardial damage in mice afflicted with DCM.

New insight of the efficacy trimetazidine in patients with peripheral arterial disease: a meta-analysis

BACKGROUND

This review aims to examine the impact of trimetazidine on skeletal muscle function in patients suffering from peripheral artery disease (PAD).

METHODS

We searched for studies, both experimental and observational research, concerning the comparison of trimetazidine administration to placebo/standard of care in patients with PAD in PubMed, ScienceDirect, and Cochrane. Meta-analyses of the included studies were performed using Review Manager v5.4. Clinical parameters [ankle-brachial index (ABI) and maximum walking distance (MWD)] were analyzed.

RESULTS

Three observational studies involving 378 participants with PAD satisfied predefined criteria. There was no substantial difference between the examined groups' on ABI (pre- and post-intervention) (MD = - 0.06 [- 0.19 to 0.07], p = 0.38, I2 = 90%). Meanwhile, MWD improvement was significantly higher (MD = 14.15 [6.05-22.25], p = 0.0006, I2 = 37%) in trimetazidine group than in the control group.

CONCLUSIONS

Current evidence from our meta-analysis suggests the beneficial role of trimetazidine's anti-ischemic effect in PAD patients by improving MWD, while it has an insignificant influence on ABI.

Biochemical Aspects That Lead to Abusive Use of Trimetazidine in Performance Athletes: A Mini-Review

Trimetazidine (TMZ), used for treating stable angina pectoris, has garnered attention in the realm of sports due to its potential performance-enhancing properties, and the World Anti-Doping Agency (WADA) has classified TMZ on the S4 list of prohibited substances since 2014. The purpose of this narrative mini-review is to emphasize the biochemical aspects underlying the abusive use of TMZ among athletes as a metabolic modulator of cardiac energy metabolism. The myocardium's ability to adapt its energy substrate utilization between glucose and fatty acids is crucial for maintaining cardiac function under various conditions, such as rest, moderate exercise, and intense effort. TMZ acts as a partial inhibitor of fatty acid oxidation by inhibiting 3-ketoacyl-CoA thiolase (KAT), shifting energy production from long-chain fatty acids to glucose, reducing oxygen consumption, improving cardiac function, and enhancing exercise capacity. Furthermore, TMZ modulates pyruvate dehydrogenase (PDH) activity, promoting glucose oxidation while lowering lactate production, and ultimately stabilizing myocardial function. TMZs role in reducing oxidative stress is notable, as it activates antioxidant enzymes like glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). In conclusion, TMZs biochemical mechanisms make it an attractive but controversial option for athletes seeking a competitive edge.

Neuroprotective potential of trimetazidine against tramadol-induced neurotoxicity: role of PI3K/Akt/mTOR signaling pathways

Tramadol (TRA) causes neurotoxicity whereas trimetazidine (TMZ) is neuroprotective. The potential involvement of the PI3K/Akt/mTOR signaling pathway in the neuroprotection of TMZ against TRA-induced neurotoxicity was evaluated. Seventy male Wistar rats were divided into groups. Groups 1 and 2 received saline or TRA (50 mg/kg). Groups 3, 4, and 5 received TRA (50 mg/kg) and TMZ (40, 80, or 160 mg/kg) for 14 days. Group 6 received TMZ (160 mg/kg). Hippocampal neurodegenerative, mitochondrial quadruple complex enzymes, phosphatidylinositol-3-kinases (PI3Ks)/protein kinase B levels, oxidative stress, inflammatory, apoptosis, autophagy, and histopathology were evaluated. TMZ decreased anxiety and depressive-like behavior induced by TRA. TMZ in tramadol-treated animals inhibited lipid peroxidation, GSSG, TNF-α, and IL-1β while increasing GSH, SOD, GPx, GR, and mitochondrial quadruple complex enzymes in the hippocampus. TRA inhibited Glial fibrillary acidic protein expression and increased pyruvate dehydrogenase levels. TMZ reduced these changes. TRA decreased the level of JNK and increased Beclin-1 and Bax. TMZ decreased phosphorylated Bcl-2 while increasing the unphosphorylated form in tramadol-treated rats. TMZ activated phosphorylated PI3Ks, Akt, and mTOR proteins. TMZ inhibited tramadol-induced neurotoxicity by modulating the PI3K/Akt/mTOR signaling pathways and its downstream inflammatory, apoptosis, and autophagy-related cascades.

A Potential Route to Reduce Ischemia/Reperfusion Injury in Organ Preservation

The pathophysiological process of ischemia and reperfusion injury (IRI), an inevitable step in organ transplantation, causes important biochemical and structural changes that can result in serious organ damage. IRI is relevant for early graft dysfunction and graft survival. Today, in a global context of organ shortages, most organs come from extended criteria donors (ECDs), which are more sensitive to IRI. The main objective of organ preservation solutions is to protect against IRI through the application of specific, nonphysiological components, under conditions of no blood or oxygen, and then under conditions of metabolic reduction by hypothermia. The composition of hypothermic solutions includes osmotic and oncotic buffering components, and they are intracellular (rich in potassium) or extracellular (rich in sodium). However, above all, they all contain the same type of components intended to protect against IRI, such as glutathione, adenosine and allopurinol. These components have not changed for more than 30 years, even though our knowledge of IRI, and much of the relevant literature, questions their stability or efficacy. In addition, several pharmacological molecules have been the subjects of preclinical studies to optimize this protection. Among them, trimetazidine, tacrolimus and carvedilol have shown the most benefits. In fact, these drugs are already in clinical use, and it is a question of repositioning them for this novel use, without additional risk. This new strategy of including them would allow us to shift from cold storage solutions to cold preservation solutions including multitarget pharmacological components, offering protection against IRI and thus protecting today's more vulnerable organs.

Protective or Inhibitory Effect of Pharmacological Therapy on Cardiac Ischemic Preconditioning: A Literature Review

Ischemic preconditioning (IP) is an innate phenomenon, triggered by brief, non-lethal cycles of ischemia/reperfusion applied to a tissue or organ that confers tolerance to a subsequent more prolonged ischemic event. Once started, it can reduce the severity of myocardial ischemia associated with some clinical situations, such as percutaneous coronary intervention (PCI) and intermittent aortic clamping during coronary artery bypass graft surgery (CABG). Although the mechanisms underlying IP have not been completely elucidated, several studies have shown that this phenomenon involves the participation of cell triggers, intracellular signaling pathways, and end-effectors. Understanding this mechanism enables the development of preconditioning mimetic agents. It is known that a range of medications that activate the signaling cascades at different cellular levels can interfere with both the stimulation and the blockade of IP. Investigations of signaling pathways underlying ischemic conditioning have identified a number of therapeutic targets for pharmacological manipulation. This review aims to present and discuss the effects of several medications on myocardial IP.

Synthesis and in Vivo Evaluation of Triphenylphosphonium Conjugated Trimetazidine with Enhanced Cardioprotection and Ability to Restore Mitochondrial Function

Trimetazidine exhibits great therapeutic potential in cardiovascular diseases and mitochondria-mediated cardioprotection by trimetazidine has been widely reported. In this study, to enhance its cardioprotection, the triphenylphosphonium-based modification of trimetazidine was conducted to deliver it specifically to mitochondria. Fifteen triphenylphosphonium (TPP) conjugated trimetazidine analogs were designed and synthesized. Their protective effects were evaluated in vivo using a tert-butyl hydroperoxide (t-BHP) induced zebrafish injury model. Structure-activity relationship correlations revealed the best way to couple the TPP moiety to trimetazidine, and led to a new conjugate (18a) with enhanced therapeutic properties. Compared to trimetazidine, 18a effectively protects against heart injury in the zebrafish model at a much lower concentration. Further study in t-BHP treated zebrafish and H9c2 cells demonstrated that 18a protects against cardiomyocyte death and damage by inhibiting excessive production of ROS, maintaining mitochondrial morphology, and preventing mitochondrial dysfunction. Consequently, 18a can be regarded as a potential therapeutic agent for cardioprotection.

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.

Trimetazidine inhibits liver fibrosis and hepatic stellate cell proliferation and blocks transforming growth factor-β (TGFβ)/Smad signaling in vitro and in vivo

Trimetazidine (TMZ) has been used extensively to treat coronary artery disease and to reduce fibrosis. Liver fibrosis is a reversible process. However, the impacts of TMZ on liver fibrosis triggered by CCl₄ and on hepatic stellate cells in liver fibrosis remain to be elaborated. In the current study, the liver fibrosis models were constructed by using CCl₄-induced mice and TGF-β-induced hepatic stellate cells. The involvement of TMZ in liver fibrosis was subsequently investigated. In the CCl₄-induced hepatic fibrosis mouse model, it was shown that the expression levels of alanine aminotransferase and aspartate aminotransferase were reduced after TMZ treatment; the expression levels of the extracellular matrix proteins colla1 and α-SMA were down-regulated; furthermore, the expression levels of TGFβ/Smad signaling proteins were inhibited. In TGF-β-induced hepatic stellate cells, compared to the TGF-β-induced group, cell proliferation and migration were inhibited after TMZ treatment; meanwhile, extracellular matrix protein and TGFβ/Smad signaling protein expression levels followed the same trend as in the hepatic fibrosis model. In conclusion, TMZ could block the TGFβ/Smad signaling in liver fibrosis model, with inhibiting liver fibrosis and hepatic stellate cell proliferation. This may broaden the application sphere of TMZ in liver fibrosis therapy.

Trimetazidine Therapy in Coronary Artery Disease: The Impact on Oxidative Stress, Inflammation, Endothelial Dysfunction, and Long-Term Prognosis

BACKGROUND

In coronary artery disease (CAD), reduction of perfusion in coronary arteries is followed by increases of oxidative stress and decreases of adenosine triphosphate reserve. In this condition, trimetazidine (TMZ), a metabolic anti-ischemic agent, seems to be an ideal therapeutic agent because it increases mitochondrial adenosine triphosphate production.

STUDY QUESTION

To evaluate the impact of TMZ on oxidative stress, inflammation, endothelial dysfunction, and long-term prognosis in CAD.

STUDY DESIGN

Patients with CAD with symptoms not adequately controlled were enrolled consecutively for a period of 18 months.

MEASURES AND OUTCOMES

Five hundred seventy patients with CAD were enrolled in a prospective study and divided into 4 groups in relation with the type of CAD and the addition of TMZ to optimal medical therapy (OMT). The impact of TMZ added to OMT on oxidative stress (total antioxidant status, antioxidized low-density lipoprotein antibodies, and antimyeloperoxidase antibodies), endothelial dysfunction (flow-mediated dilatation and von Willebrand factor activity), and inflammation (C-reactive protein and fibrinogen) at 6 months and on long-term prognosis in CAD in comparison with OMT at 5 years of follow-up was evaluated.

RESULTS

At 6 months, TMZ added to OMT significantly decreased the incidence of oxidative stress in CAD (P < 0.03) and reduced endothelial dysfunction and inflammation only in non-ST-elevation acute coronary syndrome (NSTE-ACS, P < 0.04). TMZ added to OMT with or without interventional/surgical vascularization led to decreased readmission for NSTE-ACS and heart failure (P < 0.05) in all patients with CAD and a significantly reduced incidence of cardiovascular death, acute myocardial infarction, and stroke (P < 0.05) in patients with NSTE-ACS at 5 years of follow-up.

CONCLUSIONS

In patients with NSTE-ACS, TMZ added to OMT with or without interventional and/or surgical reperfusion reduced oxidative stress, endothelial dysfunction, inflammation, and major acute cardiovascular events, whereas in patients with chronic coronary syndrome, TMZ decreased oxidative stress and readmission for ACS and heart failure.

Danhong Injection and Trimetazidine Protect Cardiomyocytes and Enhance Calcium Handling after Myocardial Infarction

Myocardial infarction (MI) is one of the leading causes of death worldwide. However, there is no effective treatment for MI. In this study, trimetazidine (TMZ) and Danhong injection (DHI), representing western medicine and traditional Chinese medicine for MI, were used as tools to identify vital processes in alleviating MI injury. Administration of DHI and TMZ obviously decreased myocardial infarct size, improved ultrasonic heart function, and reduced creatine kinase (CK), lactate dehydrogenase (LDH), and glutamic oxaloacetic transaminase (AST) levels after MI. RNA-seq results indicated calcium ion handling and negative regulation of apoptotic process were vital processes and DHI and TMZ obviously reduced the expression of CaMK II and inhibited cleaved caspase-3 and Bax. Furthermore, DHI and TMZ increased p-S16-PLB, p-S16T17-PLB, CACNA1C, p-RyR2, and p-PKA expression but did not affect SERCA2a expression. In addition to the enhancement of cardiac myocyte shortening amplitude, maximum shortening velocity, and calcium transients, DHI and TMZ increased sarcoplasmic reticulum calcium content and enhanced SERCA2a calcium uptake capability by upregulating the phosphorylation of PLB but did not affect calcium exclusion by NCX. In conclusion, DHI and TMZ protect against MI through inhibiting apoptosis by downregulating CaMKII pathway and enhancing cardiac myocyte contractile functions possibly through the PKA signaling pathway.

The first spectrofluorimetric approach for accurate determination of trimetazidine in its dosage forms: Application to content uniformity testing

A novel sensitive and simple spectrofluorimetric method has been developed then validated for the determination of trimetazidine in pure form and its tablets. This method is found on the reaction between trimetazidine's secondary amine moiety with NBD-Cl reagent, using borate buffer at pH 8.0 yielding a highly fluorescent product whose fluorescence intensity was measured at 526 nm (excitation at 466 nm). A calibration curve plotted showed that the linear range of the presented method was (50-700 ng/ml) with a correlation coefficient of 0.9998. The limits of detection (LOD) and limits of quantitation (LOQ) values were 15.01 and 45.50 ng/ml respectively. The presented approach was validated according to ICH guidelines and successfully applied for determining trimetazidine in its tablets with a mean percentage recovery of 99.65% ± 1.04, 99.23% ± 0.80 and 98.33% ± 1.03 for Metacardia® (20 mg), Vastor ® (20 mg) and Tricardia® (20 mg) tablets respectively. Finally, the proposed method was adopted to study the content uniformity test according to USP guidelines.

Effect of lemon balm (Melissa officinalis) extract on growth performance, digestive and antioxidant enzyme activities, and immune responses in rainbow trout (Oncorhynchus mykiss)

This study was conducted to determine the effects of dietary supplementation of lemon balm (Melissa officinalis) aqueous methanolic extract on growth performance, blood parameters, digestive and antioxidant enzyme activities, and non-specific immune responses in rainbow trout (Oncorhynchus mykiss). Fish with an average weight of 23.03 ± 0.07 g were fed a diet supplemented with an aqueous methanolic extract of lemon balm at a dose of 0 (control), 0.1 (LB0.1), 0.5 (LB0.5), and 1 g kg^-1 (LB1) for 75 days. The final weight, weight gain, and specific growth rate were observed to be significantly increased in LB0.5 and LB1 groups compared with that of the control. No differences were observed in feed conversion ratio values. WBC increased at the 45th day of the study in LB0.1 group. No differences were determined in RBC (P > 0.05). At the end of the study, lipase increased significantly in all experimental groups compared with the control. Pepsin was also elevated in LB0.5 and LB1 groups compared with the control. Increased trypsin was determined in LB1 group (P < 0.05). SOD activity increased at the end of the study in LB1 group (P < 0.05). CAT values had no differences compared with control. GR activity increased in all experimental groups compared with control. GPx improved in LB0.5 and LB1 groups significantly (P < 0.05). Lipid peroxidation was decreased in LB1 group compared with that of control, but this decrease was not significant (P < 0.05). Oxidative radical production and lysozyme activity significantly increased in LB1 group (P < 0.05). The highest MPO was determined in control group (P < 0.05). Current results suggest that lemon balm extract stimulates growth promoting antioxidant and immune responses in rainbow trout.

Extra energy for hearts with a genetic defect: ENERGY trial

Aims

Previous studies have shown that hypertrophic cardiomyopathy mutation carriers have a decreased myocardial energy efficiency, which is thought to play a key role in the pathomechanism of hypertrophic cardiomyopathy (HCM). The ENERGY trial aims to determine whether metabolic drugs correct decreased myocardial energy efficiency in HCM mutation carriers at an early disease stage.

Methods

40 genotype-positive, phenotype-negative MYH7 mutation carriers will be treated for two months with trimetazidine or placebo in a double-blind randomised study design. Directly before and after treatment, study subjects will undergo an [¹¹C]-acetate positron emission tomography/computed tomography (PET/CT) and cardiac magnetic resonance (CMR) scan to measure myocardial energy efficiency. Myocardial efficiency will be calculated as the amount of oxygen the heart consumes to perform work.

Conclusion

The ENERGY trial will be the first proof of concept study to determine whether metabolic drugs are a potential preventive therapy for HCM. Given that trimetazidine is already being used in clinical practice, there is large potential to swiftly implement this drug in HCM therapy.

Trimetazidine Protects Against Atherosclerosis by Changing Energy Charge and Oxidative Stress

BACKGROUND This study investigated the effect and the possible mechanism of trimetazidine in atherosclerosis. MATERIAL AND METHODS We established an atherosclerotic rat model by high-fat diet and vitamin D injection. Rats were separated into 3 different groups: control, atherosclerosis, and trimetazidine (n=10). The aortic artery was isolated and its morphological features were examined by hematoxylin and eosin (HE) staining. Serum low-density lipoprotein cholesterol (LDL-c), total cholesterol (TC), and triglycerides (TG) were analyzed using an automatic biochemical analyzer. Human aortic smooth muscle cells (HASMCs) were cultured and divided into 5 groups: no treatment, H₂O₂ treatment only, trimetazidine preincubation before H₂O₂ treatment, oxidized low-density lipoprotein (oxLDL) treatment only, and trimetazidine preincubation before oxLDL treatment. HASMCs proliferation was tested using the Cell Counting Kit-8. Reactive oxygen species (ROS) and malondialdehyde (MDA) levels, superoxide dismutase (SOD) activity of the aortic artery, and HASMCs were measured using commercially available kits. RESULTS HE staining assay showed that trimetazidine suppressed the progression of atherosclerosis and reduced foam cell formation in the aortic artery without affecting serum lipid levels. HASMCs proliferation assay revealed that trimetazidine alleviated the inhibitory effect of H₂O₂ on HASMCs proliferation and inhibited oxLDL-induced proliferation of HASMCs. Moreover, trimetazidine ameliorated ROS up-regulation elicited by H₂O₂ or oxLDL in HASMCs. Additionally, trimetazidine restored SOD activity and reduced MDA content of HASMCs. CONCLUSIONS Trimetazidine suppressed the progression of atherosclerosis by enhancing energy value, decreasing ROS level of aortic artery, modulating HASMCs proliferation, and reducing oxidative stress in HASMCs.

Lipid peroxidation in cardiac surgery: towards consensus on biomonitoring, diagnostic tools and therapeutic implementation

This review focuses on oxidative stress and more specifically lipid peroxidation in cardiac surgery, one of the fundamental theories of perioperative complications. We present the molecular pathways leading to lipid peroxidation and integrate analytical methods that allow detection of lipid peroxidation markers in the fluid phase with those focusing on volatile compounds in exhaled breath. In order to explore the accumulated data in the literature, we present a systematic review of quantitative analysis of malondialdehyde, a widely used lipid peroxidation product at various stages of cardiac surgery. This exploration reveals major limitations of existing studies in terms of variability of reported values and significant gaps due to discrete and variable sampling times during surgery. We also appraise methodologies that allow real-time and continuous monitoring of oxidative stress. Complimentary techniques highlight that beyond the widely acclaimed contribution of the cardiopulmonary bypass technology and myocardial reperfusion injury, the use of diathermy contributes significantly to intraoperative lipid peroxidation. We conclude that there is an urgent need to implement the theory of oxidative stress towards a paradigm change in the clinical practice. Firstly, we need to acquire definite and irrefutable information on the link between lipid peroxidation and post-operative complications by building international consensus on best analytical approaches towards generating qualitatively and quantitatively comparable datasets in coordinated multicentre studies. Secondly, we should move away from routine low-risk surgeries towards higher risk interventions where there is major unmet clinical need for improving patient journey and outcomes. There is also need for consensus on best therapeutic interventions which could be tested in convincing large scale clinical trials. As future directions, we propose combination of fluid phase platforms and 'metabography', an extended form of capnography-including real-time analysis of lipid peroxidation and volatile footprints of metabolism-for better patient phenotyping prior to and during high risk surgery towards molecular prediction, stratification and monitoring of the patient's journey.

Trimetazidine in Practice: Review of the Clinical and Experimental Evidence

All of the following traditional agents for the management of stable angina pectoris include the symptomatic treatment with heart rate–lowering agents such as β-blockers or non-dihydropyridine Ca-channel blockers, or ivabradine—the first selective sinus node I_f channel inhibitor—vasodilatators and preventive use of angiotensin-converting enzyme inhibitors affect the parameters of circulation directly. Trimetazidine exerts its anti-ischemic action by modulating cardiac metabolism without altering the hemodynamic functions, therefore represents an excellent complementary potential to the conventional angina treatment. It has a beneficial effect on the inflammatory profile and endothelial function and shows diverse benefits by reducing the number and the intensity of angina attacks and improving the clinical signs and symptoms of myocardial ischemia given as monotherapy as well as combined with other antianginal agents. Patients undergoing coronary revascularization procedures or with comorbid left ventricular dysfunction and diabetes mellitus also benefit from the protective effects of trimetazidine.

Trimetazidine does not alter metabolic substrate oxidation in cardiac mitochondria of target patient population

BACKGROUND AND PURPOSE

Trimetazidine, known as a metabolic modulator, is an anti-anginal drug used for treatment of stable coronary artery disease (CAD). It is proposed to act via modulation of cardiac metabolism, shifting the mitochondrial substrate utilization towards carbohydrates, thus increasing the efficiency of ATP production. This mechanism was recently challenged; however, these studies used indirect approaches and animal models, which made their conclusions questionable. The goal of the current study was to assess the effect of trimetazidine on mitochondrial substrate oxidation directly in left ventricular myocardium from CAD patients.

EXPERIMENTAL APPROACH

Mitochondrial fatty acid (palmitoylcarnitine) and carbohydrate (pyruvate) oxidation were measured in permeabilized left ventricular fibres obtained during coronary artery bypass grafting surgery from CAD patients, which either had trimetazidine included in their therapy (TMZ group) or not (Control).

KEY RESULTS

There was no difference between the two groups in the oxidation of either palmitoylcarnitine or pyruvate, and in the ratio of carbohydrate to fatty acid oxidation. Activity and expression of pyruvate dehydrogenase, the key regulator of carbohydrate metabolism, were also not different. Lastly, acute in vitro exposure of myocardial tissue to different concentrations of trimetazidine did not affect myocardial oxidation of fatty acid.

CONCLUSION AND IMPLICATIONS

Using myocardial tissue from CAD patients, we found that trimetazidine (applied chronically in vivo or acutely in vitro) had no effect on cardiac fatty acid and carbohydrate oxidation, suggesting that the clinical effects of trimetazidine are unlikely to be due to its metabolic effects, but rather to an as yet unidentified intracardiac mechanism.

Is "Attenuation of Oxidative Stress" Helpful to Understand the Mechanism of Remote Ischemic Preconditioning in Cardiac Surgery?

OBJECTIVES

The aim of this study was to determine the effect of remote ischemic preconditioning (RIPC) on markers of cardiac ischemia and response to oxidative stress in patients undergoing coronary artery bypass grafting (CABG) surgery.

DESIGN

A prospective, randomized, and blinded study.

SETTING

A single-center university hospital.

PARTICIPANTS

This study included patients who underwent isolated CABG surgery with cardiopulmonary bypass who were selected carefully to prevent confounding with factors known to affect markers of ischemia-reperfusion and response to oxidative stress.

INTERVENTIONS

The authors randomly assigned patients to RIPC to the left lower extremity using a blood pressure cuff (study group) or a cuff that was applied but not inflated or deflated (control group).

MEASUREMENTS AND MAIN RESULTS

At 6 hours after CABG surgery, high-sensitivity cardiac troponin T levels were significantly lower in the study group than in the control group. Levels of superoxide dismutase, an antioxidant enzyme, were significantly greater 15 minutes after release of the cross-clamp in the study group, whereas malondialdehyde levels were lower (not significantly) at 1 and 15 minutes after release of the cross-clamp. Hemodynamic parameters were not significantly different at any time point during the study.

CONCLUSIONS

The authors' method of RIPC before CABG surgery resulted in less myocardial ischemia, as indicated by lower troponin levels. Changes in levels of endogenous antioxidant enzymes supported the hypothesis that this protection from ischemia-reperfusion injury was related to scavenging of free oxygen radicals. Future studies might include a more heterogeneous population and medications that lower the body's response to oxidative stress.

Effects of trimetazidine on the Akt/eNOS signaling pathway and oxidative stress in an in vivo rat model of renal ischemia-reperfusion

Renal ischemia reperfusion (I/R) injury, which occurs during renal surgery or transplantation, is the major cause of acute renal failure. Trimetazidine (TMZ), an anti-ischemic drug, protects kidney against the deleterious effects of I/R. However its protective mechanism remains unclear. The aim of this study is to examine the relevance of Akt, endothelial nitric oxide synthase (eNOS), and hypoxia inducible factor-1α (HIF-1α) on TMZ induced protection of kidneys against I/R injury. Wistar rats were subjected to 60 min of warm renal ischemia followed by 120 min of reperfusion, or to intraperitoneal injection of TMZ (3 mg/kg) 30 min before ischemia. In sham operated group renal pedicles were only dissected. Compared to I/R, TMZ treatment decreased lactate dehydrogenase (845 ± 13 vs. 1028 ± 30 U/L). In addition, creatinine clearance and sodium reabsorption rates reached 105 ± 12 versus 31 ± 11 μL/min/g kidney weight and 95 ± 1 versus 68 ± 5%, respectively. Besides, we noted a decrease in malondialdehyde concentration (0.33 ± 0.01 vs. 0.59 ± 0.03 nmol/mg of protein) and an increase in glutathione concentration (2.6 ± 0.2 vs. 0.93 ± 0.16 µg GSH/mg of protein), glutathione peroxidase (95 ± 4 vs. 61 ± 3 µg GSH/min/mg of protein), and superoxide dismutase (25 ± 3 vs. 11 ± 2 U/mg of protein) and catalase (91 ± 12 vs. 38 ± 9 μmol/min/mg of protein) activities. Parallely, we noted a significant increase in p-Akt, eNOS, nitrite and nitrate (18 ± 2 vs. 8 ± 0.1 pomL/mg of protein), HIF-1α (333 ± 48 vs. 177 ± 14 µg/mg of protein) and heme oxygenase-1 (HO-1) levels regarding I/R. TMZ treatment improves renal tolerance to warm I/R. Such protection implicates an activation of Akt/eNOS signaling pathway, HIF-1α stabilization and HO-1 activation.

Nonantithrombotic medical options in acute coronary syndromes: old agents and new lines on the horizon

Acute coronary syndromes (ACS) constitute a spectrum of clinical presentations ranging from unstable angina and non-ST-segment elevation myocardial infarction to ST-segment myocardial infarction. Myocardial ischemia in this context occurs as a result of an abrupt decrease in coronary blood flow and resultant imbalance in the myocardial oxygen supply-demand relationship. Coronary blood flow is further compromised by other mechanisms that increase coronary vascular resistance or reduce coronary driving pressure. The goals of treatment are to decrease myocardial oxygen demand, increase coronary blood flow and oxygen supply, and limit myocardial injury. Treatments are generally divided into disease-modifying agents or interventions that improve hard clinical outcomes and other strategies that can reduce ischemia. In addition to traditional drugs such as β-blockers and inhibitors of the renin-angiotensin-aldosterone system, newer agents have expanded the number of molecular pathways targeted for treatment of ACS. Ranolazine, trimetazidine, nicorandil, and ivabradine are medications that have been shown to reduce myocardial ischemia through diverse mechanisms and have been tested in limited fashion in patients with ACS. Attenuating the no-reflow phenomenon and reducing the injury compounded by acute reperfusion after a period of coronary occlusion are active areas of research. Additionally, interventions aimed at ischemic pre- and postconditioning may be useful means by which to limit myocardial infarct size. Trials are also underway to examine altered metabolic and oxygen-related pathways in ACS. This review will discuss traditional and newer anti-ischemic therapies for patients with ACS, exclusive of revascularization, antithrombotic agents, and the use of high-intensity statins.

The effects of trimetazidine and sildenafil on bilateral cavernosal nerve injury induced oxidative damage and cavernosal fibrosis in rats

AIM

The aim of this study was to compare the effects of sildenafil and trimetazidine on bilateral cavernosal nerve injury-induced oxidative damage and fibrotic changes in cavernosal tissue in rat model.

MATERIAL AND METHODS

A total of 32 male Sprague-Dawley rats were randomly divided into 4 groups; each group consist 8 rats (control, BCI, BCI + TMZ, and BCI + sildenafil groups). Tissue superoxide dismutase (SOD), malondialdehyde (MDA), and protein carbonyl (PC) levels were determined biochemically and distribution of cavernosal fibrosis density among groups was performed histopathologically.

RESULTS

Tissue SOD levels in BCI group were significantly lower than the control group (P < 0.05). Tissue MDA and PC levels in BCI group were significantly higher than the control group (P < 0.05). TMZ and sildenafil administration significantly increased tissue SOD levels (P < 0.05) and reduced tissue MDA and PC levels (P < 0.05). Histologically, the degree of cavernosal fibrosis and collagen density was higher in BCI group in comparison to control, TMZ-treated, and sildenafil-treated groups.

CONCLUSION

BCI caused oxidative damage and increased cavernosal fibrosis in rat penis. TMZ and sildenafil treatment decreased oxidative damage and reduced the degree of fibrosis in penile tissue due to BCI.

Mitochondria-mediated cardioprotection by trimetazidine in rabbit heart failure

Trimetazidine (TMZ) is used successfully for treatment of ischemic cardiomyopathy, however its therapeutic potential in heart failure (HF) remains to be established. While the cardioprotective action of TMZ has been linked to inhibition of free fatty acid oxidation (FAO) via 3-ketoacyl CoA thiolase (3-KAT), additional mechanisms have been suggested. The aim of this study was to evaluate systematically the effects of TMZ on calcium signaling and mitochondrial function in a rabbit model of non-ischemic HF and to determine the cellular mechanisms of the cardioprotective action of TMZ. TMZ protected HF ventricular myocytes from cytosolic Ca(2+) overload and subsequent hypercontracture, induced by electrical and ß-adrenergic (isoproterenol) stimulation. This effect was mediated by the ability of TMZ to protect HF myocytes against mitochondrial permeability transition pore (mPTP) opening via attenuation of reactive oxygen species (ROS) generation by the mitochondrial electron transport chain (ETC) and uncoupled mitochondrial nitric oxide synthase (mtNOS). The majority of ROS generated by the ETC in HF arose from enhanced complex II-mediated electron leak. TMZ inhibited the elevated electron leak at the level of mitochondrial ETC complex II and improved impaired activity of mitochondrial complex I, thereby restoring redox balance and mitochondrial membrane potential in HF. While TMZ decreased FAO by ~15%, the 3-KAT inhibitor 4-bromotiglic acid did not provide protection against palmitic acid-induced mPTP opening, indicating that TMZ effects were 3-KAT independent. Thus, the beneficial effect of TMZ in rabbit HF was not linked to FAO inhibition, but rather associated with reduced complex II- and uncoupled mtNOS-mediated oxidative stress and decreased propensity for mPTP opening.

Endogenous sulfur dioxide protects against isoproterenol-induced myocardial injury and increases myocardial antioxidant capacity in rats

Recently, sulfur dioxide (SO(2)) was discovered to be produced in the cardiovascular system and to influence important biological processes. Here, we investigated changes in endogenous SO(2)/glutamic oxaloacetic transaminase (GOT) pathway in the development of isoproterenol (ISO)-induced myocardial injury in rats and the regulatory effect of SO(2) on cardiac function, myocardial micro- and ultrastructure, and oxidative stress. Wistar male rats were divided into control, ISO-treated, ISO+SO(2), and SO(2) groups. At the termination of the experiment, parameters of cardiac function and hemodynamics were measured and the micro- and ultrastructure of myocardium and stereological ultrastructure of mitochondria were analyzed. Myocardial SO(2) content was detected by high-performance liquid chromatography. GOT (key enzyme for endogenous SO(2) production) activity and gene (GOT1 and GOT2) expressions were measured, and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), hydrogen peroxide, and superoxide radical levels were assayed. SOD (SOD1 and SOD2) and GSH-Px (GSH-Px1) gene expressions were also detected. The results showed that SO(2) donor at a dose of 85 mg/(kg day) did not impact the cardiac function and structure of rats, but exerted a subtle influence on myocardial redox status. ISO-treated rats exhibited decreased cardiac function, damaged myocardial structures, and downregulated endogenous SO(2)/GOT pathway. Meanwhile, myocardial oxidative stress increased, whereas antioxidative capacity downregulated. Administration of SO(2) markedly improved cardiac function and ISO-induced myocardial damage by ameliorating the pathological structure of the myocardium and the mitochondria. At the same time, myocardial products of oxidative stress decreased, whereas antioxidative capacity increased. These results suggest that downregulation of the endogenous SO(2)/GOT pathway is likely involved in the pathogenesis of ISO-induced myocardial injury. SO(2) protects against ISO-induced myocardial injury associated with increased myocardial antioxidant capacity in rats.

Improvement of mechanical heart function by trimetazidine in db/db mice

AIM

To investigate the influence of trimetazidine, which is known to be an antioxidant and modulator of metabolism, on cardiac function and the development of diabetic cardiomyopathy in db/db mouse.

METHODS

Trimetazidine was administered to db/db mice for eight weeks. Cardiac function was measured by inserting a Millar catheter into the left ventricle, and oxidative stress and AMP-activated protein kinase (AMPK) activity in the myocardium were evaluated.

RESULTS

Untreated db/db mice exhibited a significant decrease in cardiac function compared to normal C57 mice. Oxidative stress and lipid deposition were markedly increased in the myocardium, concomitant with inactivation of AMPK and increased expression of peroxisome proliferator-activated receptor coactivator-1 alpha (PGC-1 alpha). Trimetazidine significantly improved systolic and diastolic function in hearts of db/db mice and led to reduced production of reactive oxygen species and deposition of fatty acid in cardiomyocytes. Trimetazidine also caused AMPK activation and reduced PGC-1 alpha expression in the hearts of db/db mice.

CONCLUSION

The data suggest that trimetazidine significantly improves cardiac function in db/db mice by attenuating lipotoxicity and improving the oxidation status of the heart. Activation of AMPK and decreased expression of PGC-1 alpha were involved in this process. Furthermore, our study suggests that trimetazidine suppresses the development of diabetic cardiomyopathy, which warrants further clinical investigation.

Oxidative stress and atrial fibrillation after cardiac surgery: a case-control study

BACKGROUND

New-onset postoperative atrial fibrillation (PAF) continues to be among the most common complications after cardiac surgery, leading to significant morbidity and cost. We studied the role of oxidative stress on patients after cardiopulmonary bypass.

METHODS

Patients undergoing coronary artery bypass grafting or valve procedures who exhibited new-onset PAF (n = 11) and those who remained in sinus rhythm (n = 13) were prospectively matched based on preoperative, intraoperative, and postoperative characteristics. Postoperative atrial fibrillation was assessed by electrocardiogram and must have required initiation of antiarrhythmic therapy or anticoagulation. Right atrial and skeletal muscle samples were harvested before and after cardiopulmonary bypass for oxidative protein immunostaining (Oxyblot assay). Serum samples were collected preoperatively and postoperatively at 6 hours and day 4 for microarray assessment of gene expression and to quantify total peroxide levels.

RESULTS

Patients with PAF had significantly more elevation in total peroxide levels in serum compared with patients in sinus rhythm at 6 hours (5.83 +/- 1.9 versus 2.02 +/- 0.2 fold, respectively; p = 0.039) but not at day 4 (3.81 +/- 1.2 versus 2.17 +/- 0.5 fold, respectively; p = 0.188). Patients with PAF also had significantly more myocardial oxidation compared with patients in sinus rhythm at 6 hours (4.19 +/- 1.4 versus 0.94 +/- 0.3 fold, respectively; p = 0.021). Increased serum peroxide levels in patients who exhibited PAF correlated with elevated myocardial protein oxidation but not peripheral muscle oxidation. Gene expression analysis revealed a differential genomic response in patients with new-onset PAF (more oxidation) compared with patients in sinus rhythm (more reduction).

CONCLUSIONS

Patients who exhibit PAF after cardiac surgery have significantly increased acute oxidative stress, which translates into increased myocardial oxidation. Also, patients with PAF have a differential oxidative genomic response after cardiopulmonary bypass that may predispose them to oxidative stress.

The protective effects of trimetazidine on testicular ischemia and reperfusion injury in rats

This study was designed to investigate the protective effect of trimetazidine [TMZ; 1-(2, 3, 4-trimethhoxibenzyl)-piperazine dihydrochloride], as an antioxidant agent, on torsion-detorsion-induced biochemical and histopathological changes in experimental testicular ischemia/reperfusion injury in rats. Twenty-seven male Wistar rats weighing 180-220 g were divided into five groups: control (C, n = 4), sham-operated (S, n = 4), ischemia (I, n = 6), ischemia-reperfusion (I/R, n = 6) and ischemia-reperfusion + trimetazidine (I/R + TMZ; n = 7). Control rats were used for basal normal values. In group I, 2 h torsion of the left testis was performed. In I/R and I/R + TMZ groups, following 2 h of torsion, 4 h detorsion of the testis was performed. In ischemia and I/R groups, physiologic saline was administered orally for 7 days, and the rats in I/R + TMZ group were pretreated orally with 5 mg/kg day TMZ for 7 days before inducing ischemia. At the end of each experiment, ipsilateral orchiectomies were performed for the tissue levels of malondialdehyde (MDA), glutathione peroxidase (GPx) enzyme activities and histopathological examinations in all groups. MDA levels were significantly reduced and GPx enzyme activities were significantly increased in testes in I/R+TMZ pretreated group compared to group I and I/R. The mean seminiferous tubular diameter (MSTD) and Johnsen's score were significantly better in I/R+TMZ group than groups I and I/R. Pretreatment with TMZ decreased germ cell apoptosis and caspase-3 expression in the ischemic testis. The present results show that TMZ has a protective activity in the testicular injury caused by I/R, and provide the first evidence of the role of TMZ for the prevention of I/R-induced testicular injury.