M-type pyruvate kinase 2 (PKM2) tetramerization alleviates the progression of right ventricle failure by regulating oxidative stress and mitochondrial dynamics.

BACKGROUND: Right ventricle failure (RVF) is a progressive heart disease that has yet to be fully understood at the molecular level. Elevated M-type pyruvate kinase 2 (PKM2) tetramerization alleviates heart failure, but detailed molecular mechanisms remain unclear. OBJECTIVE: We observed changes in PKM2 tetramerization levels during the progression of right heart failure and in vitro cardiomyocyte hypertrophy and explored the causal relationship between altered PKM2 tetramerization and the imbalance of redox homeostasis in cardiomyocytes, as well as its underlying mechanisms. Ultimately, our goal was to propose rational intervention strategies for the treatment of RVF. METHOD: We established RVF in Sprague Dawley (SD) rats by intraperitoneal injection of monocrotaline (MCT). The pulmonary artery pressure and right heart function of rats were assessed using transthoracic echocardiography combined with right heart catheterization. TEPP-46 was used both in vivo and in vitro to promote PKM2 tetramerization. RESULTS: We observed that oxidative stress and mitochondrial disorganization were associated with increased apoptosis in the right ventricular tissue of RVF rats. Quantitative proteomics revealed that PKM2 was upregulated during RVF and negatively correlated with the cardiac function. Facilitating PKM2 tetramerization promoted mitochondrial network formation and alleviated oxidative stress and apoptosis during cardiomyocyte hypertrophy. Moreover, enhancing PKM2 tetramer formation improved cardiac mitochondrial morphology, mitigated oxidative stress and alleviated heart failure. CONCLUSION: Disruption of PKM2 tetramerization contributed to RVF by inducing mitochondrial fragmentation, accumulating ROS, and finally promoted the progression of cardiomyocyte apoptosis. Facilitating PKM2 tetramerization holds potential as a promising therapeutic approach for RVF.

Evaluation of time-dependent phenotypes of myocardial ischemia-reperfusion in mice.

BACKGROUND: A mouse model of myocardial ischemia-reperfusion (I/R) is widely used to study myocardial ischemia-reperfusion injury (I/RI). However, few studies focus on the direct comparison of the extent of pathological events resulting from variant durations of ischemia and reperfusion process. METHODS: A mouse model of I/RI was established by ligation and perfusion of the left anterior descending coronary artery (LAD), and the dynamic changes were recorded by electrocardiogram at different stages of I/R. Subsequently, reperfusion duration was used as a variable to directly compare the phenotypes of different myocardial injury degrees induced by 3 h, 6 h and 24 h reperfusion from myocardial infarct size, myocardial apoptosis, myocardial enzyme, and inflammatory cytokine levels. RESULTS: All mice subjected to myocardial I/R surgery showed obvious myocardial infarction, extensive myocardial apoptosis, dynamic changes in serum myocardial enzyme and inflammatory cytokines, at least for the first 24 h of reperfusion. The infarct size and apoptosis rates gradually increased with the extension of reperfusion time. The peaks of serum myocardial enzyme and inflammatory cytokines occurred at 6 h and 3 h of reperfusion, respectively. We also established I/R mice models with 30 and 60 mins of ischemia. After 21 days of remodeling, longer periods of ischemia increased the degree of fibrosis and reduced cardiac function. CONCLUSIONS: In summary, we conclude that reperfusion durations of 3 h, 6 h, and 24 h induces different injury phenotypes in ischemia-reperfusion mouse model. At the same time, the ischemia duration before reperfusion also affects the degree of cardiac remodeling.

IL-38 attenuates myocardial ischemia-reperfusion injury by inhibiting macrophage inflammation.

BACKGROUND: Reperfusion therapy is the most effective approach to resolve coronary occlusion, but myocardial injury caused by excessive inflammation during myocardial ischemia-reperfusion will also pose a new threat to health. Our prior study revealed the expression pattern of interleukin-38 (IL-38) in the peripheral blood serum of patients with ischemic cardiomyopathy and the role of IL-38 in acute myocardial infarction in mice. However, its role and potential mechanisms in myocardial ischemia/reperfusion injury (MIRI) remain to be determined. METHODS AND RESULTS: The left anterior descending artery of C57BL/6 mice was transiently ligated to induce the MIRI model. We found that MIRI induced the expression of endogenous IL-38, which was mainly produced by locally infiltrating macrophages. Overexpression of IL-38 in C57BL/6 mice attenuated inflammatory injury and decreased myocardial apoptosis after myocardial ischemia-reperfusion. Furthermore, IL-38 inhibited lipopolysaccharide-induced macrophage inflammation in vitro. Cardiomyocytes cocultured with the supernatant of IL-38- and troponin I-treated macrophages showed a lower rate of apoptosis than controls. CONCLUSIONS: IL-38 attenuates MIRI by inhibiting macrophage inflammation. This inhibitory effect may be partially achieved by inhibiting the activation of NOD-like receptor pyrin domain-related protein 3 inflammasome, resulting in decreased expression of inflammatory factors and reduced cardiomyocyte apoptosis.

Mass Spectrometry-Based Detection of Mycotoxins in Imported Meat and Their Perspective Role on Myocardial Apoptosis.

BACKGROUND: Fungal mycotoxins are the secondary metabolite and are harmful to plants, animals, and humans. Common aflatoxins present and isolated from feeds and food comprises aflatoxins B1, B2, G1, and G2. Public health threats or risk of foodborne disease posed by mycotoxins, especially the export or import of such meat products are of primary concern. This study aims to determine the concentration of the level of aflatoxins B1, B2, G1, G2 M1, and M2 respectively in imported burger meat. METHOD: The present work is designed to select and collect the various sample of meat products from different sources and subjected to mycotoxin analysis by LCMS/MS. Random selection was made on sites of burger meat that was for sale. RESULTS: Simultaneous presence of several mycotoxins in the same sample of imported meat under the set conditions of LCMS/MS detected 26% (18 samples) were positive for various mycotoxins. The most frequent mycotoxins proportion in the analyzed samples was aflatoxin B1 (50%) followed by aflatoxin G1 (44%), aflatoxin G2 (38.8%), aflatoxin B2 (33%) respectively were least among all with 16.66 and 11.11%. DISCUSSION: A positive correlation is deduced between CVD and mycotoxin present in burger meat. Isolated mycotoxins initiate death receptor-mediated apoptosis, death receptor-mediated necrosis, mitochondrial-mediated apoptosis, mitochondrial-mediated necrosis, and immunogenic cell deaths through various pathways that can damage the cardiac tissues. CONCLUSION: The presence of these toxins in such samples is just the tip of the iceberg. Further investigation is necessary for complete clarifications of toxins on human health especially on CVD and other related metabolic complications.

PPARγ Regulates Macrophage Polarization by Inhibiting the JAK/STAT Pathway and Attenuates Myocardial Ischemia/Reperfusion Injury In Vivo.

This study aimed to investigate the role of PPARγ and underlying mechanisms in myocardial ischemia/reperfusion injury (IRI). IRI was surgically induced in mice and neonatal rat cardiomyocytes (NRCM) were exposed to oxygen-glucose deprivation and reoxygenation (OGD/R). Quantitative genetic analysis and western blotting were performed to assess mRNA and protein levels, respectively, of PPARγ, as well as of different inflammatory, fibrosis, and apoptosis markers in cells and tissues. PPARγ was overexpressed in the heart of mice and NRCMs by viral transfection. Apoptosis and fibrosis were detected by TUNEL and Masson's trichrome staining, respectively. Enzyme-linked immunosorbent assay was performed to detect M1 and M2 macrophage-related inflammatory factors present in mouse sera. PPARγ overexpression significantly inhibited OGD/R- and IRI-induced cardiomyocyte apoptosis and fibrosis in vitro and in vivo. Moreover, PPARγ overexpression inhibited IRI-induced secretion of M1-related proinflammatory factors, whereas it supported the secretion of M2-related anti-inflammatory factors. Notably, these events were found to be mediated by the JAK/STAT pathway. In conclusion, PPARγ regulates macrophage polarization upon IRI via the JAK/STAT pathway, which will in turn prevent myocardial apoptosis and fibrosis. Hence, PPARγ may represent a valuable target for myocardial IRI treatment.

The protective effect of the mitochondrial-derived peptide MOTS-c on LPS-induced septic cardiomyopathy.

Septic cardiomyopathy is associated with mechanisms such as excessive inflammation, oxidative stress, regulation of calcium homeostasis, endothelial dysfunction, mitochondrial dysfunction, and cardiomyocyte death, and there is no effective treatment at present. MOTS-c is a mitochondria-derived peptide (MDP) encoded by mitochondrial DNA (mtDNA) that protects cells from stresses in an AMPK-dependent manner. In the present study, we aim to explore the protective effect of MOTS-c on lipopolysaccharide (LPS)-induced septic cardiomyopathy. LPS is used to establish a model of septic cardiomyopathy. Our results demonstrate that MOTS-c treatment reduces the mRNA levels of inflammatory cytokines ( IL-1ß, IL-4, IL-6, and TNFα) in cardiomyocytes and the levels of circulating myocardial injury markers, such as CK-MB and TnT, alleviates cardiomyocyte mitochondrial dysfunction and oxidative stress, reduces cardiomyocyte apoptosis, activates cardioprotection-related signaling pathways, including AMPK, AKT, and ERK, and inhibits the inflammation-related signaling pathways JNK and STAT3. However, treatment with the AMPK pathway inhibitor compound C (CC) abolishes the positive effect of MOTS-c on LPS stress. Collectively, our research suggests that MOTS-c may attenuate myocardial injury in septic cardiomyopathy by activating AMPK and provides a new idea for therapeutic strategies in septic cardiomyopathy.

Sphingosine-1-phosphate Attenuates Endoplasmic Reticulum Stress-induced Cardiomyocyte Apoptosis Through Sphingosine-1-phosphate Receptor 1.

BACKGROUND: Endoplasmic reticulum stress (ER stress) is involved in the development and progression of various forms of heart disease and may lead to myocardial apoptosis. Sphingosine-1-phosphate (S1P) possesses cardioprotective properties, including anti-apoptosis. However, little is known about the link between S1P and ER stress-induced myocardial apoptosis. This study investigated the regulatory role of S1P in ER stress-induced apoptosis in cardiomyocytes. METHODS: ER stress and myocardial apoptosis were induced by transverse aortic constriction (TAC) or tunicamycin in mice, which were then treated with 2-acetyl-5-tetrahydroxybutyl imidazole (THI) or S1P. AC16 cells were treated with tunicamycin or thapsigargin, or pretreated with S1P, sphingosine-1-phosphate receptor (S1PR) subtype antagonists, S1PR1 agonist, and PI3K and MEK inhibitors. Cardiac function, the level of S1P in plasma and heart, ER stress markers, cell viability, and apoptosis were detected. RESULTS: S1P reduced the expression of ER stress-related molecules and ER stress-induced myocardial apoptosis in mice subjected to TAC or an injection of tunicamycin. Furthermore, in AC16 cells exposed to thapsigargin or tunicamycin, S1P decreased the expression of ER stress-related molecules, promoting cell viability and survival. Nevertheless, the S1PR1 antagonist abrogated the protection of S1P. Subsequently, in TAC S1PR1 heterozygous (S1PR1+/-) mice, S1P had no effect on ER stress and apoptosis in cardiomyocytes. Notably, in vitro, the impact of anti-ER stress-induced myocardial apoptosis by the S1PR1 agonist was reversed by PI3K and MEK inhibitors. CONCLUSION: This study is the first to demonstrate that S1P relieves ER stress-induced myocardial apoptosis via S1PR1/AKT and S1PR1/ERK1/2, which are potential therapeutic targets for heart disease.

Natural products from traditional Chinese medicine for the prevention and treatment of heart failure: progress and perspectives.

Heart failure (HF) is the end stage of several cardiovascular diseases with high mortality worldwide; however, current chemical drugs have not beneficial effect on reducing its mortality rate. Due to its properties of multiple targets components with multiple targets, natural products derived from traditional Chinese medicine (TCM) have exerts unique effects on the amelioration of the clinical symptoms of HF, yet, TCM is not widely used in the clinic since the potential therapeutic targets have not been fully investigated. Therefore, in this review, we briefly summarized the pathophysiological mechanism of HF and reviewed the published clinical evaluations of TCM and natural products from Chinese herbs to treat HF. Then, the therapeutic potential and the underlying mechanisms by which the natural products from Chinese herb exert their protective effects were further summarized. We concluded from this review that natural products from Chinese herbs have been shown to be more effective in treating HF by targeting multiple signaling pathways, including anticardiac hypertrophy, antifibrotic, anti-inflammatory, antioxidative and antiapoptotic activities. However, the major limitations of these compounds is that there are a lack of large scale, multicenter, randomized and controlled clinical trials for their use in treatment of HF, and the toxic effects of natural products from Chinese herbs also needed further investigation. Despite these limitations, further clinical trials and experimental studies will provide a better understanding of the mechanism of natural products from Chinese herbs and promote their wide use to treat HF.

KLHL38 facilitates staurosporine-induced apoptosis in HL-1 cells via myocardin degradation.

Cardiac apoptosis has been identified as one of the main precipitating factors of heart failure (HF) throughout the whole course of progressive disease. Limited to the lack of diagnostic markers and effective drug targets, cardiac apoptosis is still a major clinical challenge. Here, we reveal a potential novel therapeutic target for cardiac apoptosis. In the cause of the study, we found that KLHL38 was highly expressed in cardiac tissue of HF patients via GEO data-mining, which was further verified in the heart tissue of transverse aortic constriction mice. Meanwhile, the expression of KLHL38 is negatively correlated with myocardin protein level, which is a key cardiac apoptosis regulator. The KLHL38 overexpression obviously promoted cardiomyocyte apoptosis treated with staurosporine by facilitation of myocardin's ubiquitylation and subsequent proteasomal degradation. These findings reveal a new therapeutic target, which may provide a new theoretical foundation for the treatment of myocardial apoptosis in clinical practice.

Dapagliflozin Improves Cardiac Function, Remodeling, Myocardial Apoptosis, and Inflammatory Cytokines in Mice with Myocardial Infarction.

Dapagliflozin (DAPA) exerts cardioprotective effects in non-diabetic patients. Nonetheless, the protective mechanism remains unknown. This study aims to evaluate the performance of DAPA on cardiac function and remodeling as well as its potential mechanism in mice with myocardial infarction (MI). Here, a MI mice model was established. One week after MI, mice were treated with saline or DAPA (1.5 mg/kg/day) for 4 weeks. At the end of this study, echocardiography was performed to assess cardiac structure and function. Myocardial apoptosis was analyzed by Western blot and immunofluorescence. Inflammatory cytokines and cardiac fibrosis were analyzed by real-time PCR and Masson's trichrome stain, respectively. Results showed that DAPA improved cardiac structure and function, attenuated cardiac fibrosis, and inhibited inflammatory cytokines and myocardial apoptosis. Moreover, the inhibition of PI3K/AKT/mTOR pathway might be related to the cardioprotective role of DAPA. These findings reveal that dapagliflozin is a potential therapeutic agent for MI patients without diabetes.

Peoniflorin Preconditioning Protects Against Myocardial Ischemia/Reperfusion Injury Through Inhibiting Myocardial Apoptosis: RISK Pathway Involved.

Preconditioning with Peoniflorin, a component of traditional Chinese prescriptions, was proposed to be a potential strategy for cardioprotection against ischemia/reperfusion (I/R) injury. However, the cardioprotective effect of Peoniflorin preconditioning has not been thoroughly confirmed, and the underlying mechanism remains unclear. Here, we examined the cardioprotective effect and its mechanism of Peoniflorin preconditioning against myocardial I/R injury. Rats were subjected to 30 min of transient ischemia followed by 2 h of reperfusion with or without Peoniflorin (100 mg/kg) prior to reperfusion. Peoniflorin preconditioning significantly limited myocardial infarct size and reperfusion arrhythmias, as well as obviously attenuated the histomorphological and micromorphological damages induced by I/R injury. The reduced myocardial injury was also associated with the anti-apoptotic effect of Peoniflorin, as evidence by decreased TUNEL-positive cells, upregulation of BCL-2 expression, and downregulation of Bax and caspase-3 expression. In an effort to evaluate the mechanism responsible for the observed cardioprotective and anti-apoptotic effect, Western blot of phosphorylated protein was performed after 20 min of reperfusion. Results showed that Peoniflorin preconditioning activated both the Akt and ERK1/2 arm of the reperfusion injury salvage kinase (RISK) pathway. To further confirm this mechanism, the PI3K signaling inhibitor LY294002 and ERK1/2 signaling inhibitor PD98059 were administered in vivo. The cardioprotective and anti-apoptotic effects of Peoniflorin preconditioning were diminished but not abolished by pretreatment with LY294002 or PD98059. Taken together, these results indicate that Peoniflorin preconditioning protects the myocardial against I/R injury and inhibits myocardial apoptosis via the activation of the RISK pathway, highlighting the potential therapeutic effects of Peoniflorin on reducing myocardial I/R injury.

Qili Qiangxin capsules for chronic heart failure: A GRADE-assessed clinical evidence and preclinical mechanism.

Introduction: Chronic heart failure (CHF) has become an increasing concern with the aging of the population. This study aims to evaluate the effectiveness and safety of Qili Qiangxin capsules (QLQX) for CHF. Methods: A systematic review and meta-analysis on clinical studies was conducted. The mechanisms of preclinical studies were summarized. Results: We searched six electronic databases by 20 July 2022, and finally, 7 preclinical experiments (PEs) and 24 randomized controlled trials were included. The risk of bias was accessed by the SYRCLE and RoB 2.0 tool, respectively. PEs indicated that QLQX suppresses myocardial apoptosis, inhibits renin-angiotensin-aldosterone system activation, improves water retention, and enhances cardiocyte remodeling. In clinical studies, compared with routine treatment, QLQX could improve the indicators: clinical efficacy rate (RR = 1.16, 95% CI [1.12, 1.22], GRADE: moderate), left ventricular end-diastolic dimension (SMD = -1.04, 95% CI [-1.39, -0.70], GRADE: low), left ventricular ejection fraction (SMD = 1.20, 95% CI [0.97, 1.43], GRADE: moderate), 6-minute walk distance (SMD = 1.55, 95% CI [0.89, 2.21], GRADE: low), brain natriuretic peptide (SMD = -0.78, 95% CI [-1.06, -0.51], GRADE: low), N-terminal pro-brain natriuretic peptide (SMD = -2.15, 95% CI [-3.60, -0.71], GRADE: low), and adverse events (RR = 0.46, 95% CI [0.25, 0.87], GRADE: low). Discussion: In summary, QLQX exerts a potential mechanism of utility on myocardial apoptosis and cardiac function and has noteworthy clinical adjuvant efficacy and safety in patients with CHF. Systematic review registration: https://www.crd.york.ac.uk/prospero/.

Pericardial Adipose Tissue-Derived Leptin Promotes Myocardial Apoptosis in High-Fat Diet-Induced Obese Rats Through Janus Kinase 2/Reactive Oxygen Species/Na+/K+-ATPase Signaling Pathway.

Background Pathophysiologic mechanisms underlying cardiac structural and functional changes in obesity are complex and linked to adipocytokines released from pericardial adipose tissue (PAT) and cardiomyocyte apoptosis. Although leptin is involved in various pathological conditions, its role in paracrine action of pericardial adipose tissue on myocardial apoptosis remains unknown. This study was designed to investigate the role of PAT-derived leptin on myocardial apoptosis in high-fat diet-induced obese rats. Methods and Results Hearts were isolated from lean or high-fat diet-induced obese Wistar rats for myocardial remodeling studies. Obese rats had abnormal myocardial structure, diastolic dysfunction, greatly elevated cardiac apoptosis, enhanced cardiac fibrosis, and increased oxidative stress level. ELISA detected significantly higher than circulating leptin level in PAT of obese, but not lean, rats. Western blot and immunohistochemical analyses demonstrated increased leptin receptor density in obese hearts. H9c2 cardiomyoblasts, after being exposed to PAT-conditioned medium of obese rats, exhibited pronounced reactive oxygen species-mediated apoptosis, which was partially reversed by leptin antagonist. Moreover, leptin derived from PAT of obese rats inhibited Na+/K+-ATPase activity of H9c2 cells through stimulating reactive oxygen species, thereby activating calcium-dependent apoptosis. Pretreatment with specific inhibitors revealed that Janus kinase 2/signal transducer and activator of transcription 3 and phosphoinositide 3-kinase/protein kinase B signaling pathways were involved in leptin-induced myocardial apoptosis. Conclusions PAT-derived leptin induces myocardial apoptosis in high-fat diet-induced obese rats via activating Janus kinase 2/signal transducer and activator of transcription 3/reactive oxygen species signaling pathway and inhibiting its downstream Na+/K+-ATPase activity.

Resveratrol Pretreatment Inhibits Myocardial Apoptosis in Rats Following Coronary Microembolization via Inducing the PI3K/Akt/GSK-3ß Signaling Cascade.

PURPOSE: Coronary microembolization (CME) is associated with progressive cardiac dysfunction, myocardial inflammation, and apoptosis. Resveratrol (RES) has a considerable role in cardioprotection. However, the contribution and possible mechanisms of RES in CME have not been clearly understood. METHODS: In the current study, 40 SD rats were randomly selected and categorized into various groups including CME, CME + resveratrol (CME + RES), CME + resveratrol+ LY294002 (CME + RES + LY), and sham groups (10 animals in each group). The inert plastic microspheres (42 µm) were injected into the rats' left ventricle for developing the CME model. Then resveratrol (25 mg/kg/d) was given to the rats in the CME + RES and CME + RES + LY groups for one week before CME induction. Furthermore, LY294002 (10 mg/kg) was intraperitoneally injected into the rats of the CME + RES + LY group 0.5 hours before CME modeling. The cardiac functions, serum levels of myocardial injury biomarkers, myocardial histopathology, and mRNA and proteins associated with myocardial apoptosis were all assessed 12 hours after surgery. RESULTS: The results revealed that resveratrol pretreatment alleviated the CME-induced myocardial damage by improving cardiac dysfunction, and lowering the serum level of myocardial injury biomarkers, myocardial microinfarct size, and cardiomyocyte apoptotic index. Pretreatment with resveratrol reduced the level of proteins and mRNAs associated with the pro-apoptosis in myocardial tissues and increased the levels of proteins and mRNAs associated with the anti-apoptosis. Moreover, the combined treatment of resveratrol and LY294002 reversed the observed protective effects. CONCLUSION: Resveratrol can inhibit cardiomyocyte apoptosis, thus attenuating the CME-induced myocardial injury by triggering the PI3K/Akt/GSK-3ß cascade.

A SGLT2 Inhibitor Dapagliflozin Alleviates Diabetic Cardiomyopathy by Suppressing High Glucose-Induced Oxidative Stress in vivo and in vitro.

Diabetic cardiomyopathy (DCM) is a serious complication of diabetes mellitus (DM). One of the hallmarks of the DCM is enhanced oxidative stress in myocardium. The aim of this study was to research the underlying mechanisms involved in the effects of dapagliflozin (Dap) on myocardial oxidative stress both in streptozotocin-induced DCM rats and rat embryonic cardiac myoblasts H9C2 cells exposed to high glucose (33.0 mM). In in vivo studies, diabetic rats were given Dap (1 mg/ kg/ day) by gavage for eight weeks. Dap treatment obviously ameliorated cardiac dysfunction, and improved myocardial fibrosis, apoptosis and oxidase stress. In in vitro studies, Dap also attenuated the enhanced levels of reactive oxygen species and cell death in H9C2 cells incubated with high glucose. Mechanically, Dap administration remarkably reduced the expression of membrane-bound nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits gp91phox and p22phox, suppressed the p67phox subunit translocation to membrane, and decreased the compensatory elevated copper, zinc superoxide dismutase (Cu/Zn-SOD) protein expression and total SOD activity both in vivo and in vitro. Collectively, our results indicated that Dap protects cardiac myocytes from damage caused by hyperglycemia through suppressing NADPH oxidase-mediated oxidative stress.

Guan Xin Dan Shen formulation protects db/db mice against diabetic cardiomyopathy via activation of Nrf2 signaling.

Guan Xin Dan Shen formulation (GXDSF) is a widely used treatment for the management of coronary heart disease in China and is composed of three primary components: Dalbergiae odoriferae Lignum, Salviae miltiorrhizae Radix et Rhizoma and Panax notoginseng Radix et Rhizoma. However, the potential use of GXDSF for the management of diabetic cardiomyopathy (DCM) has not been previously assessed. The present study aimed to assess the effects of GXDSF on DCM, as well as the underlying mechanism. In the present study, db/db mice were used. Following treatment with GXDSF for 10 weeks, fasting blood glucose, insulin sensitivity, serum lipid levels and cardiac enzyme levels were detected. Cardiac pathological alterations and cardiac function were assessed by performing hematoxylin and eosin staining and echocardiograms, respectively. TUNEL assays were conducted to assess cardiomyocyte apoptosis. Additionally, reverse transcription­quantitative PCR and western blotting were performed to evaluate the expression of apoptosis­associated genes and proteins, respectively. In the model group, the db/db mice displayed obesity, hyperlipidemia and hyperglycemia, accompanied by noticeable myocardial hypertrophy and diastolic dysfunction. Following treatment with GXDSF for 10 weeks, serum triglyceride levels were lower and insulin sensitivity was enhanced in db/db mice compared with the model group, which indicated improvement in condition. Cardiac hypertrophy and dysfunction were also improved in db/db mice following treatment with GXDSF, resulting in significantly increased left ventricular ejection fraction and fractional shortening compared with the model group. Following treatment with metformin or GXDSF, model­induced increases in levels of myocardial enzymes were decreased in the moderate and high dose groups. Moreover, the results indicated that, compared with the model group, GXDSF significantly inhibited cardiomyocyte apoptosis in diabetic heart tissues by increasing Bcl­2 expression and decreasing the expression levels of Bax, cleaved caspase­3 and cleaved caspase­9. Mechanistically, GXDSF enhanced Akt phosphorylation, which upregulated antioxidant enzymes mediated by nuclear factor erythroid 2­related factor 2 (Nrf2) signaling. Collectively, the results of the present study indicated that GXDSF attenuated cardiac dysfunction and inhibited cardiomyocyte apoptosis in diabetic mice via activation of Akt/Nrf2 signaling. Therefore, GXDSF may serve as a potential therapeutic agent for the management of DCM.

Sildenafil improves right ventricular remodelling in monocrotaline-induced rats by decreasing myocardial apoptosis and activating peroxisome proliferator-activated receptors.

OBJECTIVES: To assess the effect of sildenafil on monocrotaline-induced right ventricular (RV) remodeling and investigate the possible mechanism. METHODS: Rats were subcutaneously injected with monocrotaline to establish an RV remodeling model and then administered sildenafil (25 mg/kg) from days 1 to 28. After 28 days of administration, the RV systolic pressure and the RV hypertrophy index (RVHI) were measured. The morphology of the right ventricle was observed by H&E staining. The ultrastructure of the right ventricle was observed using a transmission electron microscope. The myocardial apoptosis of the right ventricle was evaluated by TUNEL staining. The protein expression of apoptosis-related proteins and PPARs were examined by western blotting. KEY FINDINGS: The results indicated that sildenafil decreased the RV systolic pressure and RVHI, and improved the microstructure and ultrastructure of the right ventricle in monocrotaline-induced rats. In addition, sildenafil suppressed myocardial apoptosis and promoted the protein expression of PPARs of the right ventricle in monocrotaline-induced rats. CONCLUSION: Sildenafil inhibits RV remodeling in monocrotaline-induced rats, which might be partially mediated by reducing myocardial apoptosis and activating PPARs.

Puerarin pretreatment inhibits myocardial apoptosis and improves cardiac function in rats after acute myocardial infarction through the PI3K/Akt signaling pathway.

BACKGROUND: Puerarin demonstrates a protective effect in many cardiovascular diseases. However, the role of puerarin in acute myocardial infarction (AMI)-induced injury and the exact molecular mechanisms are not fully understood. OBJECTIVES: To investigate whether puerarin pretreatment improves cardiac function and to study the mechanism of action of puerarin. MATERIAL AND METHODS: Thirty rats were grouped into sham group, AMI group and AMI+puerarin (PUE) group at random (n = 10 per group). Except for the sham group, a model of AMI was established via left anterior descending artery ligation. The PUE group received puerarin 120 mg/(kg × day) for 7 days before the operation. Echocardiography was used for evaluation of cardiac function in rats and TUNEL staining for measuring myocardial apoptosis. The expression levels of p-PI3K, t-Akt, p-Akt, Bax, Bcl-2, and cleaved caspase-3 proteins were measured with western blot. RESULTS: Compared to the sham group, the AMI group demonstrated poor cardiac function and decreased p-PI3K, p-Akt and Bcl-2 proteins levels, while Bax, cleaved caspase-3, and myocardial apoptosis levels increased. Compared with the AMI group, the PUE group showed significant improvement in cardiac function and increased protein expression of p-PI3K, p-Akt and Bcl-2, while Bax and cleaved caspase-3 levels decreased and myocardial apoptosis was attenuated. CONCLUSIONS: Puerarin pretreatment in AMI can effectively improve cardiac function by inhibiting myocardial apoptosis. The molecular mechanism of this protective effect may be mediated by activating the PI3K/Akt pathway in cardiomyocytes.

Effects of D-pinitol on myocardial apoptosis and fibrosis in streptozocin-induced aging-accelerated mice.

Diabetic cardiomyopathy (DCM) causes heart failure and increases the mortality in diabetic patients. Myocardial apoptosis and fibrosis are the main features of DCM and aging. The aim is to study the underlying mechanism of D-pinitol (DP) on myocardial apoptosis and fibrosis in an elderly diabetic mouse model. The diabetic model was established by SAMP-8 mice that were injected with streptozotocin daily for five consecutive days. The mice were administrated of DP (150 mg kg-1  day-1 ) by gavage for 10 weeks. The common metabolic disorder indices, cardiac dysfunction, oxidative stress, myocardial apoptosis and fibrosis, and PI3K/Akt/mTOR pathway were investigated. Our findings suggested that DP has a protective effect on DCM, which may be related to regulating oxidative stress, and PI3K/Akt/mTOR pathway involving cardiac fibrosis and apoptosis. DP may be a novel clinical application in fighting against DCM. PRACTICAL APPLICATIONS: D-pinitol (DP) was found in large quantities in soybean and legume foods. DP has a variety of functions, including hypoglycemic, anti-oxidation, anti-inflammatory, cardioprotective, and anti-tumor activity. We used the streptozotocin-induced SAMP8 mice as the diabetic model and treated with DP. We found that DP can improve cardiac dysfunction and inhibits the oxidative stress, myocardial apoptosis and fibrosis. DP has a significant effect on diabetic cardiomyopathy (DCM). The molecular mechanisms are related to regulating oxidative stress, and PI3K/Akt/mTOR pathway involving cardiac fibrosis and apoptosis. DP can prevent and/or delay the onset of DCM.

Overexpression of lncRNA HULC Attenuates Myocardial Ischemia/reperfusion Injury in Rat Models and Apoptosis of Hypoxia/reoxygenation Cardiomyocytes via Targeting miR-377-5p through NLRP3/Caspase­1/IL­1ß Signaling Pathway Inhibition.

OBJECTIVE: Acute myocardial infarction (AMI) is characterized by myocardial tissue necrosis and activation of inflammatory response. This study aims to elucidate the potential mechanism underlying the protective effects of long non-coding RNA (lncRNA) highly up-regulated in liver cancer (HULC) against myocardial ischemia/reperfusion (I/R) injury in rat models and apoptosis of cardiomyocytes. METHODS: We firstly established rat models of myocardial I/R injury and rat cardiomyocyte (H9c2 cells) models of hypoxia/reoxygenation (H/R) injury. Sprague-Dawley (SD) neonatal rats were randomized into four groups: sham, I/R, I/R+ microRNA (miR) -377-5p mimic, and I/R+ miR-377-5p antagomir, respectively. Then, histopathological examination was applied. Apoptosis was evaluated by transferase-mediated dUTP nick end labeling (TUNEL) staining. Cell vitality was measured using MTT assay. The concentrations of creatine kinase MB (CK-MB), cardiac troponin I (cTnI), interleukin (IL) -6 (IL-6), and tumor necrosis factor-α (TNF-α) were detected by enzyme-linked immunosorbent assay (ELISA). The expression of Cleaved-Caspase-3, Caspase-3, NOD-like receptor P3 (NLRP3), Caspase-1, and IL-1ß was analyzed by immunohistochemical (IHC) or Western blot analysis. RESULTS: We found that HULC was downregulated and miR-377-5p was upregulated in IR-injured myocardial tissue and the H/R-induced H9c2 cell. Overexpression of miR-377-5p increased myocardial dysfunction and apoptosis and activated formation and secretion of IL-6 and TNF-α. The preprocessing of miR-377-5p silencing emerged opposite results. Strikingly, dual luciferase reporter assay showed that HULC was a sponge of miR-377-5p. Subsequently, mechanism experiments revealed that NLRP3/Caspase­1/IL­1ß was a target axis of miR-377-5p. In vitro, the protective effect of HULC overexpression on H9c2 cell viability and inflammation was offset by miR-377-5p silencing. Finally, rescue assay suggested that HULC-miR-377-5p -NLRP3/Caspase­1/IL­1ß axis regulated the apoptosis and inflammation of H/R-induced H9c2 cells. CONCLUSIONS: Overall, these results indicate that the protective effect of HULC against myocardial I/R injury and H/R cardiomyocyte apoptosis partially relies on the inhibition of NLRP3/Caspase­1/IL­1ß signaling pathway.