The effects of chronic trimetazidine treatment on mechanical function and fatty acid oxidation in diabetic rat hearts

The changes of cardiac energy metabolism with sodium-glucose transporter 2 inhibitor therapy

Background/aims

To investigate the specific effects of s odium-glucose transporter 2 inhibitor (SGLT2i) on cardiac energy metabolism.

Methods

A systematic literature search was conducted in eight databases. The retrieved studies were screened according to the inclusion and exclusion criteria, and relevant information was extracted according to the purpose of the study. Two researchers independently screened the studies, extracted information, and assessed article quality.

Results

The results of the 34 included studies (including 10 clinical and 24 animal studies) showed that SGLT2i inhibited cardiac glucose uptake and glycolysis, but promoted fatty acid (FA) metabolism in most disease states. SGLT2i upregulated ketone metabolism, improved the structure and functions of myocardial mitochondria, alleviated oxidative stress of cardiomyocytes in all literatures. SGLT2i increased cardiac glucose oxidation in diabetes mellitus (DM) and cardiac FA metabolism in heart failure (HF). However, the regulatory effects of SGLT2i on cardiac FA metabolism in DM and cardiac glucose oxidation in HF varied with disease types, stages, and intervention duration of SGLT2i.

Conclusion

SGLT2i improved the efficiency of cardiac energy production by regulating FA, glucose and ketone metabolism, improving mitochondria structure and functions, and decreasing oxidative stress of cardiomyocytes under pathological conditions. Thus, SGLT2i is deemed to exert a benign regulatory effect on cardiac metabolic disorders in various diseases.

Systematic review registration

https://www.crd.york.ac.uk/, PROSPERO (CRD42023484295).

The Contribution of Cardiac Fatty Acid Oxidation to Diabetic Cardiomyopathy Severity

Diabetes is a major risk factor for the development of cardiovascular disease via contributing and/or triggering significant cellular signaling and metabolic and structural alterations at the level of the heart and the whole body. The main cause of mortality and morbidity in diabetic patients is cardiovascular disease including diabetic cardiomyopathy. Therefore, understanding how diabetes increases the incidence of diabetic cardiomyopathy and how it mediates the major perturbations in cell signaling and energy metabolism should help in the development of therapeutics to prevent these perturbations. One of the significant metabolic alterations in diabetes is a marked increase in cardiac fatty acid oxidation rates and the domination of fatty acids as the major energy source in the heart. This increased reliance of the heart on fatty acids in the diabetic has a negative impact on cardiac function and structure through a number of mechanisms. It also has a detrimental effect on cardiac efficiency and worsens the energy status in diabetes, mainly through inhibiting cardiac glucose oxidation. Furthermore, accelerated cardiac fatty acid oxidation rates in diabetes also make the heart more vulnerable to ischemic injury. In this review, we discuss how cardiac energy metabolism is altered in diabetic cardiomyopathy and the impact of cardiac insulin resistance on the contribution of glucose and fatty acid to overall cardiac ATP production and cardiac efficiency. Furthermore, how diabetes influences the susceptibility of the myocardium to ischemia/reperfusion injury and the role of the changes in glucose and fatty acid oxidation in mediating these effects are also discussed.

Structural and Functional Remodeling of Mitochondria in Cardiac Diseases

Mitochondria undergo structural and functional remodeling to meet the cell demand in response to the intracellular and extracellular stimulations, playing an essential role in maintaining normal cellular function. Merging evidence demonstrated that dysregulation of mitochondrial remodeling is a fundamental driving force of complex human diseases, highlighting its crucial pathophysiological roles and therapeutic potential. In this review, we outlined the progress of the molecular basis of mitochondrial structural and functional remodeling and their regulatory network. In particular, we summarized the latest evidence of the fundamental association of impaired mitochondrial remodeling in developing diverse cardiac diseases and the underlying mechanisms. We also explored the therapeutic potential related to mitochondrial remodeling and future research direction. This updated information would improve our knowledge of mitochondrial biology and cardiac diseases’ pathogenesis, which would inspire new potential strategies for treating these diseases by targeting mitochondria remodeling.

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 prevents diabetic cardiomyopathy by inhibiting Nox2/TRPC3-induced oxidative stress

Diabetic cardiomyopathy (DCM) is characterized by cardiac hypertrophy, fibrosis, oxidative stress and inflammation. Trimetazidine (TMZ), a potent metabolism modulator, has been shown to be cardioprotective in experimental models of ischaemia-reperfusion and type 2 diabetes-induced cardiomyopathy. The present study examined whether TMZ inhibits cardiomyopathy induced by insulin-dependent type 1 diabetes. Wistar rats were randomly divided into control group (vehicle alone), diabetes mellitus (DM; induced by streptozocin (STZ) injection) group and DM treated with TMZ (DM/TMZ) group. Cardiac function, histology, plasma biochemistry and molecular mechanism were assessed. STZ induced diabetes in rats as indicated by hyperglycemia, increased and decreased levels of advanced glycation end products (AGEs) and insulin respectively. Diabetic rats were characterized by left ventricular dysfunction, cardiachypertrophy and fibrosis and signs of inflammation and oxidative stress in the myocardium, which were accompanied by elevated levels of NADPH oxidase 2 (Nox2) and transient receptor potential channel 3 (TRPC3) in the heart. TMZ treatment ameliorated diabetes-associated structural and functional alterations by inhibiting Nox2 and TRPC3 without having any effects on glucose, insulin and AGEs levels. These results suggest that TMZ could be used as a therapy to treat cardiomyopathy associated with type 1 induced diabetes mellitus.

PPARβ/δ and lipid metabolism in the heart

Cardiac lipid metabolism is the focus of attention due to its involvement in the development of cardiac disorders. Both a reduction and an increase in fatty acid utilization make the heart more prone to the development of lipotoxic cardiac dysfunction. The ligand-activated transcription factor peroxisome proliferator-activated receptor (PPAR)β/δ modulates different aspects of cardiac fatty acid metabolism, and targeting this nuclear receptor can improve heart diseases caused by altered fatty acid metabolism. In addition, PPARβ/δ regulates glucose metabolism, the cardiac levels of endogenous antioxidants, mitochondrial biogenesis, cardiomyocyte apoptosis, the insulin signaling pathway and lipid-induced myocardial inflammatory responses. As a result, PPARβ/δ ligands can improve cardiac function and ameliorate the pathological progression of cardiac hypertrophy, heart failure, cardiac oxidative damage, ischemia-reperfusion injury, lipotoxic cardiac dysfunction and lipid-induced cardiac inflammation. Most of these findings have been observed in preclinical studies and it remains to be established to what extent these intriguing observations can be translated into clinical practice. This article is part of a Special Issue entitled: Heart Lipid Metabolism edited by G.D. Lopaschuk.

Mitochondrial fatty acid oxidation alterations in heart failure, ischaemic heart disease and diabetic cardiomyopathy

Heart disease is a leading cause of death worldwide. In many forms of heart disease, including heart failure, ischaemic heart disease and diabetic cardiomyopathies, changes in cardiac mitochondrial energy metabolism contribute to contractile dysfunction and to a decrease in cardiac efficiency. Specific metabolic changes include a relative increase in cardiac fatty acid oxidation rates and an uncoupling of glycolysis from glucose oxidation. In heart failure, overall mitochondrial oxidative metabolism can be impaired while, in ischaemic heart disease, energy production is impaired due to a limitation of oxygen supply. In both of these conditions, residual mitochondrial fatty acid oxidation dominates over mitochondrial glucose oxidation. In diabetes, the ratio of cardiac fatty acid oxidation to glucose oxidation also increases, although primarily due to an increase in fatty acid oxidation and an inhibition of glucose oxidation. Recent evidence suggests that therapeutically regulating cardiac energy metabolism by reducing fatty acid oxidation and/or increasing glucose oxidation can improve cardiac function of the ischaemic heart, the failing heart and in diabetic cardiomyopathies. In this article, we review the cardiac mitochondrial energy metabolic changes that occur in these forms of heart disease, what role alterations in mitochondrial fatty acid oxidation have in contributing to cardiac dysfunction and the potential for targeting fatty acid oxidation to treat these forms of heart disease.

Trimetazidine revisited: a comprehensive review of the pharmacological effects and analytical techniques for the determination of trimetazidine

Trimetazidine (TMZ) is an effective and well-tolerated antianginal drug that possesses protective properties against ischemia-induced heart injury. Growing interest in metabolic modulation in recent years urged an up-to-date review of the literature on TMZ. This review consists of two major sections: (1) comprehensive and critical information about the pharmacological effects, mechanism of action, pharmacokinetics, side effects, and current usage of TMZ, and (2) developments in analytical techniques for the determination of the drug in raw material, pharmaceutical dosage forms, and biological samples.