Drug-induced cardiomyopathy: Characterization of a rat model by [18F]FDG/PET and [99mTc]MIBI/SPECT

Pathological Alterations in Heart Mitochondria in a Rat Model of Isoprenaline-Induced Myocardial Injury and Their Correction with Water-Soluble Taxifolin

Mitochondrial damage and associated oxidative stress are considered to be major contributory factors in cardiac pathology. One of the most potent naturally occurring antioxidants is taxifolin, especially in its water-soluble form. Herein, the effect of a 14-day course of the peroral application of the water-soluble taxifolin (aqTAX, 15 mg/kg of body weight) on the progression of ultrastructural and functional disorders in mitochondria and the heart's electrical activity in a rat model of myocardial injury induced with isoprenaline (ISO, 150 mg/kg/day for two consecutive days, subcut) was studied. The delayed ISO-induced myocardial damage was accompanied by an increase in the duration of RR and QT intervals, and long-term application of aqTAX partially restored the disturbed intraventricular conduction. It was shown that the injections of ISO lead to profound ultrastructural alterations of myofibrils and mitochondria in cardiomyocytes in the left ventricle myocardium, including the impairment of the ordered arrangement of mitochondria between myofibrils as well as a decrease in the size and the number of these organelles per unit area. In addition, a reduction in the protein level of the subunits of the respiratory chain complexes I-V and the activity of the antioxidant enzymes catalase, glutathione peroxidase, and Mn-SOD in mitochondria was observed. The application of aqTAX caused an increase in the efficiency of oxidation phosphorylation and a partial restoration of the morphometric parameters of mitochondria in the heart tissue of animals with the experimental pathology. These beneficial effects of aqTAX are associated with the inhibition of lipid peroxidation and the normalization of the enzymatic activities of glutathione peroxidase and Mn-SOD in rat cardiac mitochondria, which may reduce the oxidative damage to the organelles. Taken together, these data allow one to consider this compound as a promising cardioprotector in the complex therapy of heart failure.

The Detrimental Effect of Pre-Treatment with Ivermectin on Myocardial Ischemia

INTRODUCTION

Ivermectin (IVM) is a broad-spectrum anti-parasitic agent with potential antibacterial, antiviral, and anti-cancer effects. There are limited studies on the effects of IVM on cardiovascular diseases, so the present study sought to determine the effects of pre-treatment with IVM on myocardial ischemia in both ex vivo and in vivo.

METHODS

In the ex vivo part, two groups of control and treated rats with IVM (0.2 mg/kg) were examined for cardiac function and arrhythmias by isolated heart perfusion. In the in vivo part, four groups, namely, control, IVM, Iso (MI), and Iso + IVM 0.2 mg/kg were used. Subcutaneous injection of isoproterenol (100 mg/kg/day) for 2 consecutive days was used for the induction of myocardial infarction (MI) in male Wistar rats. Then electrocardiogram, hemodynamic factors, cardiac hypertrophy, and malondialdehyde (MDA) levels were investigated.

RESULTS

The ex vivo results showed that administration of IVM induces cardiac arrhythmia and decreases the left ventricular maximal rate of pressure increase (contractility) and maximal rate of pressure decline (relaxation). The isoproterenol-induced MI model used as an in vivo model showed that cardiac hypertrophy were increased with no improvement in the hemodynamic and electrocardiogram pattern in the IVM-treated group in comparison to MI (Iso) group. However, the MDA level was lower in the IVM-treated group.

CONCLUSION

IVM pre-treatment demonstrates detrimental effects in cardiac ischemia through exacerbation of cardiac arrhythmia, myocardial dysfunction, and increased cardiac hypertrophy. Therefore, the use of IVM in ischemic heart patients should be done with great caution.

Astragaloside IV promotes pharmacological effect of Descurainia sophia seeds on isoproterenol-induced cardiomyopathy in rats by synergistically modulating the myosin motor

Descurainia sophia seeds (DS), Astragalus mongholicus (AM), and their formulas are widely used to treat heart failure caused by various cardiac diseases in traditional Chinese medicine practice. However, the molecular mechanism of action of DS and AM has not been completely understood. Herein, we first used mass spectrometry coupled to UPLC to characterize the chemical components of DS and AM decoctions, then applied MS-based quantitative proteomic analysis to profile protein expression in the heart of rats with isoproterenol-induced cardiomyopathy (ISO-iCM) before and after treated with DS alone or combined with AM, astragaloside IV (AS4), calycosin-7-glucoside (C7G), and Astragalus polysaccharides (APS) from AM. We demonstrated for the first time that DS decoction alone could reverse the most of differentially expressed proteins in the heart of the rats with ISO-iCM, including the commonly recognized biomarkers natriuretic peptides (NPPA) of cardiomyopathy and sarcomeric myosin light chain 4 (MYL4), relieving ISO-iCM in rats, but AM did not pronouncedly improve the pharmacological efficiency of DS. Significantly, we revealed that AS4 remarkably promoted the pharmacological potency of DS by complementarily reversing myosin motor MYH6/7, and further downregulating NPPA and MYL4. In contrast, APS reduced the efficiency of DS due to upregulating NPPA and MYL4. These findings not only provide novel insights to better understanding in the combination principle of traditional Chinese medicine but also highlight the power of mass spectrometric proteomics strategy combined with conventional pathological approaches for the traditional medicine research.