Cardiomyocyte Damage Research Articles

Protective mechanism of tetramethylpyrazine on cardiovascular system

Tetramethylpyrazine is the main component of Ligusticum chuanxiong. Studies have found that tetramethylpyrazine has a good protective effect against cardiovascular diseases. In the heart, tetramethylpyrazine can reduce myocardial ischemia/reperfusion injury by inhibiting oxidative stress, regulating autophagy, and inhibiting cardiomyocyte apoptosis. Tetramethylpyrazine can also reduce the damage of cardiomyocytes caused by inflammation, relieve the fibrosis and hypertrophy of cardiomyocytes in infarcted myocardium, and inhibit the expansion of the cardiac cavity after myocardial infarction. In addition, tetramethylpyrazine also has a protective effect on the improvement of familial dilated cardiomyopathy. Besides, the mechanisms of tetramethylpyrazine on blood vessels are more abundant. It can inhibit endothelial cell apoptosis by reducing oxidative stress, maintain vascular endothelial function and homeostasis by inhibiting inflammation and glycocalyx degradation, and protect vascular endothelial cells by reducing iron overload. Tetramethylpyrazine also has a certain inhibitory effect on thrombosis. It can play an anti-thrombotic effect by reducing inflammatory factors and adhesion molecules, inhibiting platelet aggregation, and suppressing the expression of fibrinogen and von Willebrand factor. In addition, tetramethylpyrazine can also reduce the level of blood lipid in apolipoprotein E-deficient mice, inhibit the subcutaneous deposition of lipids, inhibit the transformation of macrophages into foam cells, and inhibit the proliferation and migration of vascular smooth muscle cells, thereby reducing the formation of atherosclerotic plaque. In combination with network pharmacology, the protective mechanism of tetramethylpyrazine on the cardiovascular system may be mainly achieved through the regulation of phosphatidylinositol 3 kinase/protein kinase B(PI3K/Akt), hypoxia-inducible factor 1(HIF-1), and mitogen-activated protein kinase(MAPK) pathways. Tetramethylpyrazine hydrochloride and sodium chloride injection has been approved for clinical application, but some adverse reactions have been found in clinical application, which need to be paid attention to.

ADSC-derived exosomes attenuate myocardial infarction injury by promoting miR-205-mediated cardiac angiogenesis

BackgroundAcute myocardial infarction is a major health problem and is the leading cause of death worldwide. Myocardial apoptosis induced by myocardial infarction injury is involved in the pathophysiology of heart failure. Therapeutic stem cell therapy has the potential to be an effective and favorable treatment for ischemic heart disease. Exosomes derived from stem cells have been shown to effectively repair MI injury-induced cardiomyocyte damage. However, the cardioprotective benefits of adipose tissue-derived mesenchymal stem cell (ADSC)-Exos remain unknown. This study aimed to investigate the protective effects of exosomes from ADSC on the hearts of MI-treated mice and to explore the underlying mechanisms.MethodsCellular and molecular mechanisms were investigated using cultured ADSCs. On C57BL/6J mice, we performed myocardial MI or sham operations and assessed cardiac function, fibrosis, and angiogenesis 4 weeks later. Mice were intramyocardially injected with ADSC-Exos or vehicle-treated ADSCs after 25 min following the MI operation.ResultsEchocardiographic experiments showed that ADSC-Exos could significantly improve left ventricular ejection fraction, whereas ADSC-Exos administration could significantly alleviate MI-induced cardiac fibrosis. Additionally, ADSC-Exos treatment has been shown to reduce cardiomyocyte apoptosis while increasing angiogenesis. Molecular experiments found that exosomes extracted from ADSCs can promote the proliferation and migration of microvascular endothelial cells, facilitate angiogenesis, and inhibit cardiomyocytes apoptosis through miRNA-205. We then transferred isolated exosomes from ADSCs into MI-induced mice and observed decreased cardiac fibrosis, increased angiogenesis, and improved cardiac function. We also observed increased apoptosis and decreased expression of hypoxia-inducible factor-1α and vascular endothelial growth factor in HMEC-1 transfected with a miRNA-205 inhibitor.ConclusionIn summary, these findings show that ADSC-Exos can alleviate cardiac injury and promote cardiac function recovery in MI-treated mice via the miRNA-205 signaling pathway. ADSC-Exos containing miRNA205 have a promising therapeutic potential in MI-induced cardiac injury.

Bardoxolone Methyl Ameliorates Myocardial Ischemia/Reperfusion Injury by Activating the Nrf2/HO-1 Signaling Pathway.

Myocardial ischemia/reperfusion (I/R) injury is a severe heart problem resulting from restoring coronary blood flow to the myocardium after ischemia. This study is aimed at ascertaining the therapeutic efficiency and action mechanism of bardoxolone methyl (BARD) in myocardial I/R injury. In male rats, myocardial ischemia was performed for 0.5 h, and then, reperfusion lasted for 24 h. BARD was administrated in the treatment group. The animal's cardiac function was measured. Myocardial I/R injury serum markers were detected via ELISA. The 2,3,5-triphenyltetrazolium chloride (TTC) staining was used to estimate the infarction. H&E staining was used to evaluate the cardiomyocyte damage, and Masson trichrome staining was used to observe the proliferation of collagen fiber. The apoptotic level was assessed via the caspase-3 immunochemistry and TUNEL staining. Oxidative stress was measured through malondialdehyde, 8-hydroxy-2'-deoxyguanosine, superoxide dismutase, and inducible nitric oxide synthases. The alteration of the Nrf2/HO-1 pathway was confirmed via western blot, immunochemistry, and PCR analysis. The protective effect of BARD on myocardial I/R injury was observed. In detail, BARD decreased cardiac injuries, reduced cardiomyocyte apoptosis, and inhibited oxidative stress. For mechanisms, BARD treatment significantly activates the Nrf2/HO-1 pathway. BARD ameliorates myocardial I/R injury by inhibiting oxidative stress and cardiomyocyte apoptosis via activating the Nrf2/HO-1 pathway.

Occlusion preconditioned mice are resilient to hypobaric hypoxia-induced myocarditis and arrhythmias due to enhanced immunomodulation, metabolic homeostasis, and antioxidants defense.

Sea-level residents experience altitude sickness when they hike or visit altitudes above ~2,500 m due to the hypobaric hypoxia (HH) conditions at such places. HH has been shown to drive cardiac inflammation in both ventricles by inducing maladaptive metabolic reprogramming of macrophages, which evokes aggravated proinflammatory responses, promoting myocarditis, fibrotic remodeling, arrhythmias, heart failure, and sudden deaths. The use of salidroside or altitude preconditioning (AP) before visiting high altitudes has been extensively shown to exert cardioprotective effects. Even so, both therapeutic interventions have geographical limitations and/or are inaccessible/unavailable to the majority of the population as drawbacks. Meanwhile, occlusion preconditioning (OP) has been extensively demonstrated to prevent hypoxia-induced cardiomyocyte damage by triggering endogenous cardioprotective cascades to mitigate myocardial damage. Herein, with the notion that OP can be conveniently applied anywhere, we sought to explore it as an alternative therapeutic intervention for preventing HH-induced myocarditis, remodeling, and arrhythmias. OP intervention (6 cycles of 5 min occlusion with 200 mmHg for 5 min and 5 min reperfusion at 0 mmHg - applying to alternate hindlimb daily for 7 consecutive days) was performed, and its impact on cardiac electric activity, immunoregulation, myocardial remodeling, metabolic homeostasis, oxidative stress responses, and behavioral outcomes were assessed before and after exposure to HH in mice. In humans, before and after the application of OP intervention (6 cycles of 5 min occlusion with 130% of systolic pressure and 5 min reperfusion at 0 mmHg - applying to alternate upper limb daily for 6 consecutive days), all subjects were assessed by cardiopulmonary exercise testing (CPET). Comparing the outcomes of OP to AP intervention, we observed that similar to the latter, OP preserved cardiac electric activity, mitigated maladaptive myocardial remodeling, induced adaptive immunomodulation and metabolic homeostasis in the heart, enhanced antioxidant defenses, and conferred resistance against HH-induce anxiety-related behavior. Additionally, OP enhanced respiratory and oxygen-carrying capacity, metabolic homeostasis, and endurance in humans. Overall, these findings demonstrate that OP is a potent alternative therapeutic intervention for preventing hypoxia-induced myocarditis, cardiac remodeling, arrhythmias, and cardiometabolic disorders and could potentially ameliorate the progression of other inflammatory, metabolic, and oxidative stress-related diseases.

Dexmedetomidine alleviates myocardial ischemia–reperfusion injury by down-regulating miR-34b-3p to activate the Jagged1/Notch signaling pathway

BackgroundMyocardial ischemia/reperfusion (I/R) injury is a fatal event that usually occurs after reperfusion therapy for myocardial infarction. Dexmedetomidine (Dex) has been shown to be beneficial in the treatment of myocardial infarction, however, its underlying mechanism for regulating I/R injury is unclear. MethodsH9c2 cell and rat models of I/R injury were established via oxygen-glucose deprivation reoxygenation (OGD/R) and occlusion of the left anterior descending branch of coronary artery, respectively. Flow cytometry, MTT, or DHE assay detected cell activity, ROS, or apoptosis, respectively. The expression levels of miR-34b-3p and related mRNAs were determined using qRT-PCR. Related protein expression levels were detected by Western blotting and ELISA test. The interaction between miR-34b-3p and Jagged1 was assessed by dual luciferase reporter and RIP assays. The morphology of cardiac tissue was examined by TTC, HE, and TUNEL labeling. ResultsDex markedly inhibited the inflammatory damage and apoptosis caused by OGD/R in H9c2 cells. MiR-34b-3p and Jagged1 levels were increased and decreased in myocardial I/R injury model, respectively, while Dex reversed this effect. Moreover, miR-34b-3p was firstly reported to directly bind and decrease Jagged1 expression, thereby inhibiting Notch signaling pathway. Transfection of agomiR-34b-3p or Jagged1 silencing eliminated Dex’s defensive impact on OGD/R-induced cardiomyocytes damage. Dex relieved the myocardial I/R injury of rats via inhibiting miR-34b-3p and further activating Notch signaling pathway. ConclusionDex protected myocardium from I/R injury via suppressing miR-34b-3p to activate Jagged1-mediated Notch signaling pathway. Our findings revealed a novel mechanism underlying of Dex on myocardial I/R injury.

Comprehensive Analysis of Mitochondrial Dynamics Alterations in Heart Diseases

The most common alterations affecting mitochondria, and associated with cardiac pathological conditions, implicate a long list of defects. They include impairments of the mitochondrial electron transport chain activity, which is a crucial element for energy formation, and that determines the depletion of ATP generation and supply to metabolic switches, enhanced ROS generation, inflammation, as well as the dysregulation of the intracellular calcium homeostasis. All these signatures significantly concur in the impairment of cardiac electrical characteristics, loss of myocyte contractility and cardiomyocyte damage found in cardiac diseases. Mitochondrial dynamics, one of the quality control mechanisms at the basis of mitochondrial fitness, also result in being dysregulated, but the use of this knowledge for translational and therapeutic purposes is still in its infancy. In this review we tried to understand why this is, by summarizing methods, current opinions and molecular details underlying mitochondrial dynamics in cardiac diseases.

Emodin Regulates lncRNA XIST/miR-217 Axis to Protect Myocardial Ischemia-Reperfusion Injury.

This study is aimed at investigating the effect of emodin on myocardial ischemia-reperfusion injury (MIRI) and mechanism. Eighty healthy adult male SD rats (weighing 230-250 g) were utilized to establish I/R model, which were randomly divided into five groups (16 rats in each group): sham operation group, myocardial ischemia-reperfusion injury group (I/R group), emodin group, emodin +NC group, and emodin +XIST group. The contents of CK, CK-MB, LDH, and HBDH in serum were determined by ELISA kit. LDH was detected by ELISA assay, SOD was detected by the xanthine oxidase method, and MDA was detected by the thiobarbituric acid method. The relative expression of XIST and miR-217 was evaluated by RT-qPCR. Western blot was applied to detect the protein expression. Flow cytometry was applied to detect cardiomyocyte apoptosis. Myocardial infarction area was obviously increased in I/R model rats, while emodin decreased the myocardial infarction in I/R model rats. In addition, cardiac enzymes (CK, CK-MB, LDH, and HBDH) and apoptosis were obviously increased in MIRI model rats, while emodin obviously decreased cardiac enzymes and apoptosis. The ROS and MDA levels were raised while the activities of SOD were declined in the I/R model group. The ROS and MDA levels were decreased while the activities of SOD were raised in the emodin group. The XIST expression was markedly raised in the I/R model group while decreased in the emodin group, and the overexpression of XIST reversed the protective effect of emodin on myocardial infarction, oxidative stress, and cardiomyocyte apoptosis. In addition, XIST directly regulated the expression of miR-217, and si-XIST inhibited H/R-induced oxidative damage of cardiomyocytes via inhibiting miR-217. Emodin protected MIRI both in vitro and in vivo via inhibiting lncRNA XIST to upregulate miR-217.

Endothelial Glycocalyx and Cardiomyocyte Damage Is Prevented by Recombinant Syndecan-1 in Acute Myocardial Infarction

The outer layer of endothelial cells (ECs), consisting of the endothelial glycocalyx (eGC) and the cortex (CTX), provides a protective barrier against vascular diseases. Structural and functional impairments of their mechanical properties are recognized as hallmarks of endothelial dysfunction and can lead to cardiovascular events, such as acute myocardial infarction (AMI). This study investigated the effects of AMI on endothelial nanomechanics and function and the use of exogenous recombinant syndecan-1 (rSyn-1), a major component of the eGC, as recovering agent. ECs were exposed invitro to serum samples collected from patients with AMI. In addition, in situ ECs of exvivo aorta preparations derived from a mouse model for AMI were employed. Effects were quantified by using atomic force microscopy-based nanoindentation measurements, fluorescence staining, and histologic examination of the mouse hearts. AMI serum samples damaged eGC/CTX and augmented monocyte adhesion to the endothelial surface. In particular, the anaphylatoxins C3a and C5a played an important role in these processes. The impairment of endothelial function could be prevented by rSyn-1 treatment. In the mouse model of myocardial infarction, pretreatment with rSyn-1 alleviated eGC/CTX deterioration and reduced cardiomyocyte damage in histologic analyses. However, echocardiographic measurements did not indicate a functional benefit. These results provide new insights into the underlying mechanisms of AMI-induced endothelial dysfunction and perspectives for future studies on the benefit of rSyn-1 in post-AMI treatment.

Atrial inflammation and microvascular thrombogenicity are increased in deceased COVID-19 patients

BackgroundHistopathological studies have shown inflammation, cardiomyocyte injury, and microvascular thrombosis in the ventricular myocardium of patients with coronavirus disease 2019 (COVID-19). However, although atrial dysfunction is common in COVID-19, little is known about histopathological changes in the atria of the heart. We therefore analyzed inflammation, cardiomyocyte injury, and microvascular thrombogenicity in the atria of deceased patients with COVID-19. MethodsAtrial tissue was obtained from autopsied COVID-19 (n=16) patients and control patients (n=10) and analyzed using immunohistochemistry. The infiltration of CD45+ leukocytes, CD3+ T lymphocytes, CD68+ macrophages, MPO+ neutrophils, and Tryptase+ mast cells were quantified as well as cardiomyocyte damage and microvascular thrombosis. In addition, Tissue Factor (TF) and Factor XII (FXII) were quantified as markers of microvascular thrombogenicity. ResultsThe numbers of lymphocytes, macrophages, and neutrophils were significantly increased in the atrial myocardium and epicardial atrial adipose tissue of COVID-19 patients compared with the control group. This was accompanied by dispersed cardiomyocyte injury, the occasional presence of microvascular thrombosis, and an increased presence of TF and FXII in the microvascular endothelium. ConclusionsSevere COVID-19 induces inflammation, cardiomyocyte injury, and microvascular thrombosis in the atria of the heart.

Waterpipe smoke inhalation potentiates cardiac oxidative stress, inflammation, mitochondrial dysfunction, apoptosis and autophagy in experimental hypertension

Cigarette smoking worsens the health of hypertensive patients. However, less is known about the actions and underlying mechanisms of waterpipe smoke (WPS) in hypertension. Therefore, we evaluated the effects of WPS inhalation in mice made hypertensive (HT) by infusing angiotensin II for six weeks. On day 14 of the infusion of angiotensin II or vehicle (normotensive; NT), mice were exposed either to air or WPS for four consecutive weeks. Each session was 30 min/day and 5 days/week. In NT mice, WPS increased systolic blood pressure (SBP) compared with NT air-exposed group. SBP increase was elevated in HT+WPS group versus either HT+air or NT+WPS. Similarly, the plasma levels of brain natriuretic peptide, C-reactive protein, 8-isoprostane and superoxide dismutase were increased in HT+WPS compared with either HT+air or NT+WPS. In the heart tissue, several markers of oxidative stress and inflammation were increased in HT+WPS group vs the controls. Furthermore, mitochondrial dysfunction in HT+WPS group was more affected than in the HT+air or HT+WPS groups. WPS inhalation in HT mice significantly increased cardiac DNA damage, cleaved caspase 3, expression of the autophagy proteins beclin 1 and microtubule-associated protein light chain 3B, and phosphorylated nuclear factor κ B, compared with the controls. Compared with HT+air mice, heart histology of WPS-exposed HT mice showed increased cardiomyocyte damage, neutrophilic and lymphocytic infiltration and focal fibrosis. We conclude that, in HT mice, WPS inhalation worsened hypertension, cardiac oxidative stress, inflammation, mitochondrial dysfunction, DNA damage, apoptosis and autophagy. The latter effects were associated with a mechanism involving NF-κB activation.

Low Dose of 5-Aminolevulinic Acid Hydrochloride Alleviates the Damage in Cardiomyocytes Induced by Lenvatinib via PI3K/AKT Signaling Pathway.

Lenvatinib is an oral tyrosine kinase inhibitor (TKI), and has been applied in the clinical trials for the treatment of hepatocellular carcinoma (HCC). The function of 5-aminolevulinic acid hydrochloride (ALA) treatment in protecting cardiomyocytes under lenvatinib stimulation was investigated. H9c2 cells were treated with 2 mg/mL lenvatinib for 48 h and 1 mM ALA in the lenvatinib with low dose 5-aminolevulinic acid treatment group (LL) group, 10 mM ALA in the lenvatinib with high-dose 5-aminolevulinic acid treatment group (LH) group and cells without treatment were used as an internal control. C57/BL mice were treated with 10 mg/kg lenvatinib and 200 mg/kg ALA in the LL group and 400 mg/kg ALA in the LH group by gavage once per day for 4 weeks. The proliferation ability of cells was detected using the methyl thiazolyl tetrazolium (MTT) assay. Target gene expression was calculated through real-time quantitative PCR (qPCR), and target protein expression was calculated through Western blotting analysis. The concentrations of cardiovascular protective factors were detected using enzyme linked immunosorbent assay (ELISA). In these experiments, 10 mM ALA significantly increased the viability rate of cardiomyocytes (105.4 ± 8.0%) compared with the single lenvatinib treatment group (73.2 ± 6.5%). We also noticed that activation of nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathways were activated after low-dose ALA treatment. 5-ALA treatment led to the downregulation of intercellular cell adhesion molecule-1 (ICAM-1) (0.81- and 0.71-fold), vascular cell adhesion molecule (VCAM) (0.63- and 0.66-fold), angiotensin I (ANGI) (0.88- and 0.66-fold), ANGII (0.66- and 0.48-fold) and upregulation of endothelial nitric oxide synthases (eNOS) (1.25- and 1.89-fold) compared with non 5-ALA treatment group. With more experiments on animal models, low-dose of ALA treatment might be a therapeutic strategy to alleviate the damage to cardiomyocytes induced by lenvatinib.

Transmembrane BAX inhibitor motif containing 6 suppresses presenilin-2 to preserve mitochondrial integrity after myocardial ischemia-reperfusion injury.

Myocardial ischemia-reperfusion (I/R) damage is characterized by mitochondrial damage in cardiomyocytes. Transmembrane BAX inhibitor motif containing 6 (TMBIM6) and presenilin-2 (PS2) participate in multiple mitochondrial pathways; thus, we investigated the impact of these proteins on mitochondrial homeostasis during an acute reperfusion injury. Myocardial post-ischemic reperfusion stress impaired myocardial function, induced structural abnormalities and promoted cardiomyocyte death by disrupting the mitochondrial integrity in wild-type mice, but not in TMBIM6 transgenic mice. We found that TMBIM6 bound directly to PS2 and promoted its post-transcriptional degradation. Knocking out PS2 in mice reduced I/R injury-induced cardiac dysfunction, inflammatory responses, myocardial swelling and cardiomyocyte death by improving the mitochondrial integrity. These findings demonstrate that sufficient TMBIM6 expression can prevent PS2 accumulation during cardiac I/R injury, thus suppressing reperfusion-induced mitochondrial damage. Therefore, TMBIM6 and PS2 are promising therapeutic targets for the treatment of cardiac reperfusion damage.

Red Ginseng Is a Therapeutic Candidate for Chronic Doxorubicin‐Induced Cardiomyopathy in Mice

Doxorubicin‐induced cardiomyopathy (DICM) is associated with a poor prognosis, and effective therapeutic drug candidates have yet to be identified. Furthermore, whether basic animal models reflect the clinical pathogenesis of DICM should be carefully examined. Although the exact mechanisms underlying the development of DICM are complex and remain unclear, oxidative stress is strongly implicated as a contributing factor. Therefore, we investigated the effects of ginseng (the root of Panax ginseng: Gin), an inexpensive and safe drug with antioxidant properties. We previously conducted a meta‐analysis that yielded results suggesting its efficacy in humans. However, this study did not examine the efficacy of ginseng in detail. Therefore, this study investigated the efficacy of red ginseng (steamed and dried ginseng cultivated for over six years; RGin) in a mouse model of chronic DICM to elucidate its potential therapeutic benefits. RGin prevented the decrease in left ventricular ejection fraction associated with doxorubicin (DXR) administration and prolonged survival in DBA/2 mice. In addition, RGin reduced DXR‐induced cardiomyocyte damage. These findings highlight its potential as a therapeutic option for the treatment of DICM.

Clinical findings using echocardiography and plasma cardiac troponin I and pathological findings in dogs with hypertrophic cardiomyopathy: A retrospective study.

Hypertrophic cardiomyopathy (HCM) is considered rare in dogs, and there is a lack of clinical data. Cardiac troponin I (cTnI) is a biomarker of cardiomyocyte damage and necrosis and can be used to diagnose cat and human HCM. We investigated whether the presence of cTnI in clinical data can be used in conjunction with echocardiography to diagnose canine HCM. This study comprised client-owned dogs with clinical evidence of concentric hypertrophy on echocardiographic images, serum total thyroxine levels of ≤5 µg/dl, systolic blood pressure of ≤180 mmHg, and absence of aortic stenosis. All cases were necropsied. Cardiomyocyte hypertrophy (mean diameter, 18.3 ± 1.8 µm), myocardial fiber disarray (70%), interstitial fibrosis (80%), and small vessel disease (100%) were assessed. In dogs with HCM, the left ventricles were concentric, almost symmetrical, and hypertrophied above the aortic diameter. The end-diastolic interventricular septum normalized to body weight [intraventricular septal thickness in diastole (IVSDN)] was 0.788 [interquartile range (IQR), 0.7-0.92], which exceeded the normal range (5%-95%, IQR: 0.33-0.52). In total, 70% of the dogs with HCM had syncope and dyspnea, and all dogs had high cTnI levels (median, 3.94 ng/ml), exceeding the upper limit of normal (0.11 ng/ml) and indicating cardiomyocyte damage. IVSDN and serum cTnI levels were correlated (ρ = 0.839, p = 0.01). Ventricular wall thickening and high serum cTnI levels can provide a presumptive diagnosis of HCM and prompt the initiation of treatment or additional diagnostic investigations.

Sensitively detecting endogenous homocysteine in human serum and cardiomyocytes with a specific fluorescent probe.

The elevated level of homocysteine (Hcy) in circulating blood is generally regarded as a risk factor for a variety of diseases including acute myocardial infarction (AMI), but there is no clear answer to whether circulating Hcy can be used for AMI diagnosis. To address it, here we have designed a tetraazacycle-based fluorescent probe for sensitive detection of endogenous Hcy in AMI patients' serum and cardiomyocytes, showing a perfect selectivity over other biothiols (e.g. Cys and GSH). It mainly relies on the formation of a stable six-membered ring structure when this probe responds to Hcy, which is accompanied by a weakening of photoinduced electron transfer (PET) that induces a sharp increase in the fluorescence emission. In this way, Hcy can be probed in biofluids with high sensitivity. We then employed this fluorescent sensor to statistically analyze the levels of Hcy in human circulating blood, indicating a big difference between AMI patients and the healthy participants. To tell whether such a difference is applicable to AMI diagnosis, we further compare the expression levels of Hcy in cardiomyocytes and other tissue cells. It reveals a lower level of endogenous Hcy in cardiomyocytes, implying no direct relationship between the elevated Hcy and cardiomyocyte damage. This observation suggests that Hcy in circulating blood cannot be utilized as a potential biomarker for AMI diagnosis, although it is proven as a risk factor for this disease.

Trastuzumab-induced human cardiomyocyte damage through the Notch2/JAK2/STAT3 pathway

ObjectiveTrastuzumab is the preferred drug for the treatment of breast cancer. However, research on the cellular mechanisms of trastuzumab's potential cardiotoxicity is insufficient. The purpose of this study was to explore the toxic effects and potential mechanism of action of trastuzumab on cardiomyocytes. MethodHuman Cardiomyocyte (HCM) viability was assessed using the MTT method. HCM apoptosis was detected using the Hoechst33342/PI Fluorescent staining. The LDH and CK activities of the cell were measured using commercially available LDH and CK assay kits. The expression levels of Notch2, JAK2, STAT3, cleaved caspase 3, bax, and bcl 2 in HCMs were detected using western blotting. ResultsThe results showed that 250 mg/L trastuzumab induced cardiomyocyte injury and apoptosis, inhibited viability, activated the Notch2 receptor, and inhibited JAK2/STAT3 expression in HCM. Inhibition of Notch2 expression in HCM by targeted siNotch2 transfection reversed the trastuzumab-induced injury and apoptosis, and the expression of JAK2/STAT3 returned to normal levels. ConclusionsTrastuzumab induces Notch2 expression by inhibiting the JAK2/STAT3 pathway of HCMs, promotes cell apoptosis, and causes cardiomyocyteinjury. Notch2 may be a potential target of trastuzumab-inducedmyocardial injury. This experiment reveals the mechanism of trastuzumab-induced cardiotoxicity, providing a theoretical basis for the application of trastuzumab.

Shikonin Suppresses High Glucose-Induced Cardiomyocyte Damage by Down-Regulating circ_0000491

Shikonin Suppresses High Glucose-Induced Cardiomyocyte Damage by Down-Regulating circ_0000491

Aerobic exercise prevents cardiomyocyte damage caused by oxidative stress in early cardiovascular disease by increasing vascularity while L-arginine supplementation prevents it by increasing activation of the enzyme nitric oxide synthase.

L-Arginine and chronic exercise reduce oxidative stress. However, it is unclear how they affect cardiomyocytes during cardiovascular disease (CVD) development. The aim of this research was to investigate the possible effects of L-arginine supplementation and aerobic training on systemic oxidative stress and their consequences on cardiomyocytes during cardiometabolic disease onset caused by excess fructose. Wistar rats were allocated into four groups: control (C), fructose (F, 10% fructose in water), fructose training (FT; moderate running, 50-70% of the maximal velocity), and fructose arginine (FA; 880 mg/kg/day). Fructose was given for two weeks and fructose plus treatments for the subsequent eight weeks. Body composition, blood glucose, insulin, lipid profile, lipid peroxidation, nitrite, metalloproteinase-2 (MMP-2) activity, left ventricle histological changes, microRNA-126, -195, and -146, eNOS, p-eNOS, and TNF-α expressions were analyzed. Higher abdominal fat mass, triacylglycerol level, and insulin level were observed in the F group, and both treatments reversed these alterations. Myocardial vascularization was impaired in fructose-fed groups, except in FT. Cardiomyocyte hypertrophy was observed in all fructose-fed groups. TNF-α levels were higher in fructose-fed groups than in the C group, and p-eNOS levels were higher in the FA than in the C and F groups. Lipid peroxidation was higher in the F group than in the FT and C groups. During CVD onset, moderate aerobic exercise reduced lipid peroxidation, and both training and L-arginine prevented metabolic changes caused by excessive fructose. Myocardial vascularization was impaired by fructose, and cardiomyocyte hypertrophy appeared to be influenced by pro-inflammatory and oxidative environments.

Rutin and quercetagetin enhance the regeneration potential of young and aging bone marrow-derived mesenchymal stem cells in the rat infarcted myocardium.

Myocardial infarction (MI) damages cardiomyocytes permanently and compromises cardiac function. Mesenchymal stem cells (MSCs) with the potential to differentiate into multiple lineages are considered as one of the best options for the treatment of MI. However, aging affects their regeneration capability. With age, reactive oxygen species (ROS) accumulate in cells ultimately causing cell death. To successfully utilize these stem cells in clinic, novel strategies to improve their functional capability should be explored. In this study, we aimed to enhance the cardiac regeneration potential of bone marrow MSCs derived from aging rats by treating them with antioxidants, rutin or quercetagetin in separate in vivo experiments. Oxidative stress was induced by treating MSCs of young and aging rats with different concentrations of H2O2 which resulted in an increase in the ROS level. MSCs were treated with rutin or quercetagetin at varying concentrations and exposed to H2O2. It was observed that both antioxidants significantly (P < 0.001) suppressed H2O2-induced intracellular ROS accumulation in a dose-dependent manner. An optimized concentration of 10µM rutin or quercetagetin was used for the in vivo experiments. MI models were developed in aging rats by ligation of left anterior descending artery and treated MSCs were transplanted in the MI models. Echocardiography was performed after 2 and 4weeks of cell transplantation to evaluate the functional status of the infarcted heart and histological analysis was performed after 4weeks to assess cardiac regeneration. Significant improvement was observed in cardiac parameters including LVEF% (P < 0.001), LVFS% (P < 0.01 and P < 0.001), LVIDd (P < 0.01 and P < 0.001), LVIDs (P < 0.001), LVEDV (P < 0.001) and LVESV (P < 0.001) in the treated young as well as aging MSCs. It is concluded from these findings that rutin and quercetagetin treatment enhance the regeneration efficiency of young and aging MSCs in vivo. These antioxidants can be effectively utilized to improve cellular therapy for myocardial infarction by suppressing ROS production.

Rosmarinic acid protects against lipopolysaccharide-induced cardiac dysfunction via activating Sirt1/PGC-1α pathway to alleviate mitochondrial impairment.

Sepsis-induced cardiomyopathy is a decisive factor that plays a critical role in the high mortality of septic patients in the critically ill. Mitochondrial dysfunction occurring during sepsis is a vital contributor to the pathogenesis of myocardial damage. Rosmarinic acid (RA), a natural poly-phenolic compound, has showed cardio-protective and mitochondrial protective effect. The present study was aimed to investigate the effect of RA on sepsis-induced cardiomyopathy. Adult mice were subjected to intraperitoneal injection of saline (control) or lipopolysaccharide (LPS, 5mg/kg) to mimic sepsis-induced cardiomyopathy. Immediately after LPS challenge, vehicle or RA (100 mg/kg/day) was administrated via gavage. Cardiac function was examined with echocardiographic analyses 12 hours after LPS challenge and cumulative survival of mice was recorded for 8 days. Heart tissues were harvested 12 hours after LPS challenge to perform histological analyses and determine mitochondrial function. We found RA significantly improved cardiac function and survival of LPS-injected mice. Histologically, RA attenuated LPS-mediated cardiomyocyte damage, indicated by decreased cardiomyocyte apoptosis and improved myocardial swollen and disarrangement. Moreover, RA attenuated LPS-mediated myocardial mitochondrial dysfunction, indicated by improved mitochondrial ultrastructure, increased mitochondrial membrane potential (MMP), synthesis of adenosine triphosphate (ATP), markedly decreased reactive oxygen species (ROS) level and alleviated oxidative stress in heart tissues. RA treatment downregulated protein expression of Sirt1 and peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), and Sirt1 inhibition blocked protective effect of RA on LPS-induced myocardial damage and mitochondrial dysfunction. Collectively, RA attenuates LPS-induced cardiac dysfunction via activating Sirt1/PGC-1α pathway to alleviate mitochondrial impairment. It may be a promising cardio-protective drug to be used for septic patients.