Reduced apoptosis after acute myocardial infarction by simvastatin

Recent perspectives on the early expression immunohistochemical markers in post-mortem recognition of myocardial infarction

Acute Myocardial Infarction (AMI) refers to the death of heart tissue in the absence ofperfusion. It is one of the top causes of death globally, particularly in middle andhigher-age groups. However, for the pathologist, the post-mortem macroscopic andmicroscopic diagnosis of early AMI remains challenging. In the early acute stage ofAMI, no microscopic visible signs of tissue alterations like necrosis and neutrophilinfiltration can be seen. In such a scenario, immunohistochemistry (IHC) accounts forthe most suitable and safest alternative to study early diagnostic cases by selectivelydetecting changes in the cell population. This systematic review focuses on themultiple causes/changes that lead to the privation of blood flow as well as tissuechanges induced by the absence of perfusion.We performed a systematic review of the last 10-15 years' publications that focused ondetecting immunohistochemical changes that appear in the cell population in case ofacute myocardial infarction. We found around 160 articles on AMI, which we narroweddown to 50 with the use of specific filters such as: "Acute Myocardial Infarction," "Ischemia," "Hypoxia," "Forensic," "Immunohistochemistry, and "Autopsy." The presentreview comprehensively highlights the current knowledge of specific IHC markers usedas gold standards during post-mortem investigation of acute myocardial infarction. Thepresent review comprehensively highlights the current knowledge of specific IHCmarkers used as gold standards during post-mortem investigation of acute myocardialinfarction, and some new potential immunohistochemical markers that can be used inthe early detection of myocardial infarction.

The crosstalk among autophagy, apoptosis, and pyroptosis in cardiovascular disease

In recent years, the mechanism of cell death has become a hotspot in research on the pathogenesis and treatment of cardiovascular disease (CVD). Different cell death modes, including autophagy, apoptosis, and pyroptosis, are mosaic with each other and collaboratively regulate the process of CVD. This review summarizes the interaction and crosstalk of key pathways or proteins which play a critical role in the entire process of CVD and explores the specific mechanisms. Furthermore, this paper assesses the interrelationships among these three cell deaths and reviews how they regulate the pathogenesis of CVD. By understanding how these three cell death modes go together we can learn about the pathogenesis of CVD, which will enable us to identify new targets for preventing, controlling, and treating CVD. It will not only reduce mortality but also improve the quality of life.

Simvastatin-loaded nano-niosomes efficiently downregulates the MAPK-NF-κB pathway during the acute phase of myocardial ischemia-reperfusion injury

BACKGROUND

Simvastatin can potentially mitigate acute inflammatory phase of myocardial ischemia-reperfusion injury. However, these effects negatively influenced by its poor bioavailability, low water solubility and high metabolism. Here, we investigated the effects of SIM-loaded nano-niosomes on a rat model of MI/R injury to find a drug delivery method to tackle the barriers.

METHODS

Nano-niosomes' characteristics were identified using dynamic light scattering and transmission electron microscopy. Fifty male Wistar rats were divided into five groups: Sham; MI/R; MI/R + nano-niosome; MI/R + SIM; MI/R + SIM-loaded nano-niosomes. Left anterior descending artery was ligated for 45 min, and 3 mg/kg SIM, nano-niosomes, or SIM-loaded nano-niosomes was intramyocardially injected ten min before the onset of reperfusion. ELISA assay was used to assess cardiac injury markers (cTnI, CK-MB) and inflammatory cytokines (TNF-α, IL-6, TGF-β, MPC-1). Expression level of MAPK-NF-κB and histopathological changes were evaluated by western blot and hematoxylin & eosin staining, respectively.

RESULTS

the size of nano-niosome was 137 nm, reached to 163 nm when simvastatin was loaded. To achieve optimized niosomes span 80, a drug/cholesterol ratio of 0.4 and seven min of sonication time was applied. Optimized entrapment efficiency of SIM-loaded nano-niosomes was 98.21%. Inflammatory cytokines and the expression level of MAPK and NF-κB were reduced in rats receiving SIM-loaded nano-niosomes compared to MI/R + SIM and MI/R + SIM-loaded nano-niosomes.

CONCLUSION

Our results showed that SIM-loaded nano-niosomes could act more efficiently than SIM in alleviating the acute inflammatory response of reperfusion injury via downregulating the activation of MAPK-NF-κB.

Role of circRNA circ_0000080 in myocardial hypoxia injury

This study aimed to investigate the potential role of circRNA circ_0000080 in myocardial hypoxia injury and the underlying mechanisms. Patients with myocardial hypoxia injury who were admitted to Xi’an No. 1 Hospital, China, were included in this study. The expression levels of circ_0000080, miR-367-5p, and COX2 were analyzed by real-time quantitative PCR (RT-qPCR); cell viability was measured by cell counting kit-8 (CCK-8) assay; and apoptosis was detected by flow cytometry. In addition, the release of cytokines was determined by Enzyme-linked immunosorbent assay (ELISA), and the binding sites between miR-367-5p and circ_0000080/COX2 were predicted by bioinformatics analysis and confirmed by dual-luciferase reporter and RNA pull-down assays. circ_0000080 was upregulated in patients with MI and in H9c2 cells treated with H₂O₂ and hypoxia/reoxygenation (H/R). Silencing circ_0000080 reduced the H/R-mediated apoptosis of cardiomyocytes and secretion of pro-inflammatory cytokines. Moreover, circ_0000080 functioned as an miR-367-5p sponge to regulate the expression of COX2. Downregulated miR-367-5p or overexpressed COX2 degraded cellular functions of cardiomyocytes. circ_0000080 knockdown alleviated myocardial hypoxia injury through the miR-367-5p/COX2 axis.

Effect of endoplasmic reticulum stress-induced apoptosis in the role of periodontitis on vascular calcification in a rat model

The present study aimed to investigate the mechanism(s) through which endoplasmic reticulum stress (ERS)-induced apoptosis, in the role of periodontitis, affects vascular calcification. Rat models of periodontitis, vascular calcification, periodontitis-vascular calcification, and a normal group were established. Cardiovascular tissues were obtained, and hematoxylin-eosin staining was applied to demonstrate the morphological changes in vascular tissues. Immunohistochemical staining was applied to analyze apoptosis in cardiovascular tissues. The expression levels of apoptotic factor cysteinyl aspartate specific proteinase 3 (Caspase-3), ERS-induced apoptotic factors glucose-regulated protein 78 (GRP78), 94 (GRP94), and ERS-induced apoptosis pathways Caspase-12, C/EBP homologous protein (CHOP), and c-Jun N-terminal kinase (JNK) were analyzed and compared. Hematoxylin-eosin staining revealed that the arterial layers in the normal group were structurally intact. The structural damage to the aortic wall gradually aggravated from the periodontitis group to the vascular calcification group to the combined group. The immunohistochemistry results showed Caspase-3, GRP78, GRP94, and ERS-induced apoptosis pathways in the cardiovascular tissues cells in the periodontitis group, vascular calcification group, and combined group. The Caspase-3, GRP78, GRP94, and CHOP expression levels in the combined group were significantly higher than that in the normal group (P < 0.05); however, the Capase-12 and JNK expression levels in the four groups exhibited no significant differences (P > 0.05). Apoptosis induced by ERS is involved in the effect of periodontitis on vascular calcification and might be mainly achieved through the activation of the CHOP transcription pathway.

Exploration of the molecular targets and mechanisms of suxiao xintong dropping pills for myocardial infarction by network pharmacology method

BACKGROUND

Suxiao Xintong dropping pills (SXXTDP), a traditional Chinese medicine, is widely applied for treating myocardial infarction (MI). However, its therapy mechanisms are still unclear. Therefore, this research is designed to explore the molecular mechanisms of SXXTDP in treating MI.

METHODS

The active ingredients of SXXTDP and their corresponding genes of the active ingredients were retrieved from the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database. MI-related genes were identified via analyzing the expression profiling data (accession number: GSE97320). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed to study the shared genes of drug and disease. Through protein-protein interaction (PPI) network and the Cytoscape plugin cytoHubba, the hub genes were screened out. The compounds and hub targets binding were simulated through molecular docking method.

RESULTS

We obtained 21 active compounds and 253 corresponding target genes from TCMSP database. 1833 MI-related genes were identified according to P<0.05 and |log2FC| ≥ 0.5. 27 overlapping genes between drug and disease were acquired. GO analysis indicated that overlapping genes were mainly enriched in MAP kinase activity and antioxidant activity. KEGG analysis indicated that overlapping genes were mainly enriched in IL-17 signaling pathway and TNF signaling pathway. We obtained 10 hub genes via cytoHubba plugin. Six of the 10 hub genes, including PTGS2, MAPK14, MMP9, MAPK1, NFKBIA, and CASP8, were acted on molecular docking verification with their corresponding compounds of SXXTDP.

CONCLUSION

SXXTDP may exert cardioprotection effect through regulating multiple targets and multiple pathways in MI.

Investigating the Pharmacological Mechanisms of SheXiang XinTongNing Against Coronary Heart Disease Based on Network Pharmacology and Experimental Evaluation

SheXiang XinTongNing (XTN), which is composed of six traditional Chinese herbs, is a commercially available Chinese patent medicine that has been widely used as the treatment of coronary heart disease (CHD). Its mechanisms against coronary heart disease, however, remain largely unknown. This study aimed to investigate the pharmacological mechanisms of XTN against CHD via network pharmacology and experimental evaluation. In this study, GO enrichment and KEGG pathway enrichment were firstly performed for acquiring the potentially active constituents of XTN, the candidate targets related to coronary heart disease, the drug-components-targets network as well as the protein-protein interaction network and further predicting the mechanisms of XTN against coronary heart disease. Subsequently, a series of in vitro experiments, specifically MTT assay, flow cytometry and Real-time quantitative polymerase chain reaction analysis, and a succession of in vivo experiments, including Tunel staining and immunohistochemical staining were conducted for further verification. Results showed that Bcl-2, IGF1, CASP3 were the key candidate targets which significantly associated with multiple pathways, namely PI3K-Akt signaling pathway and MAPK signaling pathway. It indicated that the potential mechanism of XTN against CHD may be predominantly associated with cell apoptosis. The in vitro experimental results showed that XTN treatment remarkably decreased the apoptotic rate and Bax/Bcl-2 ratio of H9c2 cells. Histological results confirmed that XTN not only effectively alleviated oxidative damage caused by myocardial ischemia but inhibited cell apoptosis. Given the above, through the combined utilization of virtual screening and experimental verification, the findings suggest that XTN makes a significant contribution in protecting the heart from oxidative stress via regulating apoptosis pathways, which lays the foundations and offers an innovative idea for future research.

Simvastatin-loaded nano-niosomes confer cardioprotection against myocardial ischemia/reperfusion injury

Although simvastatin (SIM) has been proven to be a powerful agent against myocardial ischemia/reperfusion (MI/R) injury, poor water solubility, short half-life, and low bioavailability have made it futile while using conventional drug delivery system. Hence, this study aims to investigate therapeutic efficacy of SIM-loaded nano-niosomes on MI/R injury. Surface active agent film hydration method was used to synthesize nano-niosomes. The physicochemical properties of nano-niosomes were characterized using dynamic light scattering (DLS) and transmission electron microscopy (TEM). Moreover, niosomes were characterized in entrapment efficiency (EE) and releasing pattern. Male Wistar rats were assigned into five groups (sham, MI/R, SIM, nano-niosomes, and SIM-loaded nano-niosomes). To induce MI/R, left thoracotomy was performed along mid-axillary line. The LAD ligation lasted for 45 min. A single dose (3 mg/kg) of drug formulations was injected into myocardial. Echocardiography was performed to evaluate cardiac function. The expression of the necroptosis markers was evaluated using western blot assay. Particle size of only nano-niosomes was about 137 nm, whereas a shift to 163 nm was observed in nano-niosomes containing SIM. Optimized niosomes were achieved by span 80, drug to cholesterol ratio of 0.4 with 7-min sonication time. EE of optimized nano-niosomes containing SIM was 98.21%. The effects of nano-niosomes containing on improving cardiac function and inhibiting necroptosis pathway was more efficient than the SIM group. Our findings have suggested that nano-niosomes can be applied as a notable drug delivery method to augment stability, bioavailability, and therapeutic efficacy of SIM, when it used against myocardial I/R injury.

MiR-448-5p/VEGFA Axis Protects Cardiomyocytes from Hypoxia Through Regulating the FAS/FAS-L Signaling Pathway

Bioinformatics analysis showed that miR-448-5p expression in the myocardial tissue of rats with myocardial infarction significantly increased, suggesting that it may participate in myocardial cell apoptosis in myocardial infarction. This study aimed to explore the protective effects of miR-448-5p on hypoxic myocardial cells.H9C2 cells were cultured and subjected to anoxia for 2, 4, and 8 hours to establish a hypoxia model. MiR-448-5p mimic and inhibitor were transfected into the cells; then, a dual-luciferase experiment was conducted to verify the targeting relationship between miR-448-5p and VEGFA. Cell viability and apoptosis was detected by cell counting kit-8 and flow cytometry, respectively. The expressions of apoptosis-related proteins, miR-448-5p, FAS, and FAS-L were measured using western blotting and quantitative reverse transcription-polymerase chain reaction (qRT-PCR).Hypoxia-reduced H9C2 cell viability and promoted apoptosis. MiR-448-5p expression was increased after H9C2 cell hypoxia. MiR-448-5p mimic significantly inhibited the viability and promoted the apoptosis of hypoxia-induced model cells. Hypoxia promoted the expression of apoptosis-related protein B-cell lymphoma-2 (Bcl-2) and inhibited the expressions of Bcl-2-associated x protein (Bax), cleaved caspase-3, and caspase-3, whereas the effect of inhibitor on hypoxia-reduced H9C2 cell and apoptotic protein expression were opposite to miR-448-5p mimic. MiR-448-5p targeted VEGFA and regulated its expression. Silenced VEGFA expression significantly inhibited inhibitor effect on increasing cell viability and promoted apoptosis. In addition, miR-448-5p mimic inhibited the effect of hypoxia on promoting the expressions of FAS and FAS-L of H9C2 cells. Inhibitors had the opposite effect on cell hypoxia model.The miR-448-5p/VEGFA axis could protect cardiomyocytes from hypoxia through inhibiting the FAS/FAS-L signaling pathway.

PTEN mediates serum deprivation-induced cytotoxicity in H9c2 cells via the PI3K/AKT signaling pathway

The pathogenesis of acute myocardial infarction (AMI) is associated with cardiomyocyte necrosis and apoptosis. Numerous studies have determined the regulatory effects of Phosphatase and tensin homolog (PTEN) cell proliferation and apoptosis in other cell types. However, the potential role of PTEN in cardiomyocyte is unclear. In this study, we used H9c2 cells cultured under serum deprivation to simulate the apoptosis process of myocardial infarction. Small interference RNA (siRNA) of PTEN was used to knock down the expression of PTEN. Cell viability was determined by CCK-8. Cell proliferation was examined by Edu staining, and the protein expression was analyzed by Western blot. We also evaluated the generation of ROS, the degree of DNA damage, and cell apoptosis using immunofluorescence assay. As a result, we observed that serum deprivation in H9c2 cells increased PTEN expression. Functionally, the PTEN knockdown experiment using siRNA inhibited serum deprivation-induced cell apoptosis, ROS production, and DNA damage, whereas increased cell proliferation. All these effects could be reversed by phosphatidylinositol 3-kinase (PI3K) inhibitor, which indicated the PI3K/protein kinase B (AKT) might be the critical component of the PTEN effects during serum deficiency. In conclusion, our study indicated the role of the PTEN/PI3K/AKT pathway in serum deprivation-induced cytotoxicity in H9c2 cells.

99m Tc-labeled Duramycin for detecting and monitoring cardiomyocyte death and assessing atorvastatin cardioprotection in acute myocardial infarction

This study aimed to dynamically monitor myocardial cell death using ^99m Tc-Duramycin single-photon emission computed tomography/computed tomography (micro-SPECT/CT) imaging in acute myocardial infarction (AMI) and the anti-apoptosis effect of atorvastatin for cardioprotection. Mice were randomized into three groups: AMI group, AMI with atorvastatin treatment (T-AMI) group, and sham group. Three groups of model mice were randomly selected at day 1 (D1), day 3 (D3), and day 7 (D7) day after surgery with ^99m Tc-Duramycin micro-SPECT/CT imaging. The lesion-to-normal myocardial tissue ratio (L/N) average values were 2.62 on D1, 3.89 on D3, and 1.20 on D7 for the uptake of ^99m Tc-duramycin in the infarcted region in the AMI group. The sham group presented no positive imaging in myocardium, and the L/N average values were 1.09, 1.14, and 1.10 on D1, D3, and D7, respectively. Meanwhile, ^99m Tc-linear-duramycin imaging showed no radioactive uptake in the infarction region. The T-AMI group imaging showed tracer uptake decreased obviously compared to the uptake in the infarcted region in AMI mice. ^99m Tc-Duramycin SPECT/CT imaging allowed non-invasive monitoring of myocardial cell death in a mouse model of AMI and an assessment of atorvastatin anti-apoptosis effect for cardioprotection by in vivo molecular imaging.

VEGF-A in Cardiomyocytes and Heart Diseases

The vascular endothelial growth factor (VEGF), a homodimeric vasoactive glycoprotein, is the key mediator of angiogenesis. Angiogenesis, the formation of new blood vessels, is responsible for a wide variety of physio/pathological processes, including cardiovascular diseases (CVD). Cardiomyocytes (CM), the main cell type present in the heart, are the source and target of VEGF-A and express its receptors, VEGFR1 and VEGFR2, on their cell surface. The relationship between VEGF-A and the heart is double-sided. On the one hand, VEGF-A activates CM, inducing morphogenesis, contractility and wound healing. On the other hand, VEGF-A is produced by CM during inflammation, mechanical stress and cytokine stimulation. Moreover, high concentrations of VEGF-A have been found in patients affected by different CVD, and are often correlated with an unfavorable prognosis and disease severity. In this review, we summarized the current knowledge about the expression and effects of VEGF-A on CM and the role of VEGF-A in CVD, which are the most important cause of disability and premature death worldwide. Based on clinical studies on angiogenesis therapy conducted to date, it is possible to think that the control of angiogenesis and VEGF-A can lead to better quality and span of life of patients with heart disease.

RASSF1 promotes cardiomyocyte apoptosis after acute myocardial infarction and is regulated by miR-125b

Cardiomyocyte apoptosis is a common pathological injury in association with acute myocardial infarction (AMI). In the current study, the relationship between Ras-association domain family 1 (RASSF1) and cardiomyocyte apoptosis was investigated. RASSF1 was significantly over expressed in infarcted myocardial tissues as well as in cardiomyocytes induced by hypoxia. Inhibition of RASSF1 expression alleviated cardiomyocytes apoptosis induced by hypoxia in vitro and reduced cardiomyocytes apoptosis after AMI in vivo. RASSF1 expression was directly modulated by miR-125b, which was further confirmed by luciferase reporter assay. The current study verified that the miR-125b/RASSF1 axis was involved in cardiomyocytes apoptosis. To sum up, these results suggest that RASSF1 downregulation alleviated infarction-induced cardiomyocytes apoptosis and was regulated by miR-125b.

MicroRNA-494 Inhibits the LRG1 Expression to Induce Proliferation and Migration of VECs in Rats following Myocardial Infarction

Myocardial infarction (MI) is a life-threatening cardiac event that results in extreme damage to the heart muscle. The Wnt signaling pathway has been implicated in the development of heart diseases. Hence, the current study aimed to investigate the role of microRNA (miRNA) in association with the Wnt signaling pathway to identify potential candidates for MI therapy. Differentially expressed miRNAs associated with MI occurrence were screened, and miR-494 was selected for subsequent experiments. Sprague-Dawley rats were included to establish a MI model via intraperitoneal injection of 0.1 mg/kg atropine sulfate and 40 mg/kg pentobarbital sodium. Then, the interaction between miR-494 and LRG1 was identified. The effect of miR-494 on expression of the Wnt signaling pathway-related genes, proliferation, migration, and invasion ability of fibroblasts and vascular endothelial cells (VECs) was subsequently evaluated through a series of gain- and loss-of-function experiments. The results revealed that miR-494 was poorly expressed and LRG1 was highly expressed in MI rats. miR-494 targets and downregulates LRG1, which resulted in the inactivation of the Wnt signaling pathway and promoted proliferation, migration, and invasion ability of fibroblasts and VECs. In conclusion, this study provided evidence suggesting that overexpressed miR-494 could potentially promote the proliferation, migration, and invasion of fibroblasts and VECs in MI through the inactivation of the Wnt signaling pathway by binding to LRG1.

Angiogenic function of astragaloside IV in rats with myocardial infarction occurs via the PKD1-HDAC5-VEGF pathway

The current study aimed to assess the role and mechanism of astragaloside IV (AS-IV) in myocardial infarction. A myocardial infarction model was established via the ligation of the left anterior descending artery. Rats were randomly divided into sham, DMSO, model, AS-IV, AS-IV-CID755673 and CID755673 inhibitor groups. Rats were then sacrificed following 4 weeks of treatment and segmental heart samples were obtained for hematoxylin and eosin, and masson staining. The expression of PKD1, HDAC5 and VEGF were analyzed using immunohistochemistry, reverse transcription polymerase chain reaction and western blotting. Compared with the sham and DMSO groups, the morphology of myocardium in the model and CID755673 inhibitor groups were disordered and exhibited necrotic myocardial cells and collagen tissues. Following treatment with AS-IV, the morphology of the myocardium was markedly improved and the number of new blood vessels increased. However, following treatment with CID755673, the myocardial tissue of rats became disordered, with an increased number of necrotic cells and the closure of certain vessels. The expression of PKD1, HDAC5 and VEGF mRNA and protein in myocardial tissue of model group and CID755673 inhibitor group were significantly lower than the other four groups (P<0.05), whereas these levels in the AS-IV group were significantly higher than those in the other five groups (P<0.01). Additionally, the AS-IV-CID755673 group exhibited significantly higher levels of PKD1, HDAC5 and VEGF mRNA and protein than the sham, DMSO, CID755673 inhibitor and model groups (P<0.05). Furthermore, the protein expression of pS205 PKD1, pS259 HDAC5 and pTyr951 VEGF in the myocardium of rats was comparable with that of PKD1, HDAC5 and VEGF. AS-IV may partly promote the angiogenesis of myocardial tissue in rats with myocardial infarction via the PKD1-HDAC5-VEGF pathway.

A Preclinical Systematic Review and Meta-Analysis of Astragaloside IV for Myocardial Ischemia/Reperfusion Injury

Astragaloside IV (AS-IV), the major pharmacological extract from Astragalus membranaceus Bunge, possesses a variety of biological activities in the cardiovascular systems. Here, we aimed to evaluate preclinical evidence and possible mechanism of AS-IV for animal models of myocardial ischemia/reperfusion (I/R) injury. Studies of AS-IV in animal models with myocardial I/R injury were identified from 6 databases from inception to May, 2018. The methodological quality was assessed by using CAMARADES 10-item checklist. All the data were analyzed using Rev-Man 5.3 software. As a result, 22 studies with 484 animals were identified. The quality score of studies ranged from 3 to 6 points. Meta-analyses showed AS-IV can significantly decrease the myocardial infarct size and left ventricular ejection fraction, and increase shortening fraction compared with control group (P < 0.01). Significant decreasing of cardiac enzymes and cardiac troponin and increasing of decline degree in ST-segment were reported in one study each (P < 0.05). Additionally, the possible mechanisms of AS-IV for myocardial I/R injury are promoting angiogenesis, improving the circulation, antioxidant, anti-inflammatory and anti-apoptosis. Thus, AS-IV is a potential cardioprotective candidate for further clinical trials of myocardial infarction.

The expression of microRNA-23a regulates acute myocardial infarction in patients and in vitro through targeting PTEN

Cardiovascular disease is responsible for one of the highest rates of fatality worldwide. The present study investigated the presence and influence of microRNA (miRNA)-23a in the regulation of acute myocardial infarction (AMI). A total of 6 patients with AMI and 6 normal volunteers without myocardial disease were included, and blood samples were taken to analyze the expression of miRNA‑23a by reverse transcription‑quantitative polymerase chain reaction. miRNA‑23a expression in patients with AMI was downregulated compared with the normal group. In H9C2 cells treated with H2O2, upregulation of miRNA‑23a expression increased the superoxide dismutase, glutathione and catalase activity levels, and suppressed the malonaldehyde activity level, as determined by ELISA. Western blot analysis and a caspase‑3 substrate assay demonstrated that upregulation of miRNA‑23a expression suppressed the Bcl‑2‑associated X (Bax)/Bcl‑2 protein expression ratio, caspase‑3 activity level and tumor suppressor p53 (p53) protein expression in H2O2‑induced H9C2 cells. Furthermore, downregulation of phosphatase and tensin homolog (PTEN), by the PTEN inhibitor bpV(HOpic), increased miRNA‑23a expression and suppressed the Bax/Bcl‑2 protein expression ratio, caspase‑3 activity level and p53 protein expression in H2O2‑induced H9C2 cells. Therefore, the results of the present study indicate that the expression of miRNA‑23a may regulate AMI through targeting PTEN in patients and in vitro, and PTEN/miRNA‑23a may therefore be potential targets for the clinical treatment of AMI.

Cardioprotective effect of Notch signaling on the development of myocardial infarction complicated by diabetes mellitus

The present study aimed to elucidate the role of Notch signaling in the development of myocardial infarction (MI) concomitant with diabetes in vivo and in vitro and evaluated the therapeutic effect of the Notch signaling in vitro. Streptozotocin-induced diabetic rats were subjected to 25 min of ischemia and 2 h of reperfusion. Cardiac troponin T (cTnT) and creatine kinase-MB (CK-MB) isoenzyme levels were detected. Infarct size was measured by 2,3,5-triphenyltetrazolium chloride staining. Myocardial apoptosis and fibrosis were examined by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling and Masson Trichrome staining, respectively. The mRNA and protein levels of Notch signaling components, including Notch1, Notch4, Delta-like 1, Jagged1, Mastermind-like protein 1 and p300, were quantified by reverse transcription-quantitative polymerase chain reaction and western blotting analyses, respectively. H9c2 cells were treated with/without 33 mM high glucose (HG) and/or subjected to hypoxia in the presence/absence of Jagged1. Cell viability and apoptosis were determined by MTT assay and Annexin V-fluorescein isothiocyanate/propidium iodide assay. Levels of the Notch signaling pathway members were examined. The present findings revealed that diabetes elevated CK-MB and cTnT, increased infarct size, induced myocardial apoptosis and inhibited the Notch signaling pathway in vivo after ischemia/reperfusion. Ischemia/reperfusion augmented the severity of MI in diabetic rats. Furthermore, HG reduced cell viability and induced cell apoptosis in H9c2 cells after hypoxia exposure, which was inhibited by Jagged1. We also found that HG inhibited Notch signaling in H9c2 cells after hypoxia, whereas Jagged1 exerted its cardioprotective effect on hypoxic injury (in HG environments or not) by activating the Notch signaling pathway. In conclusion, these findings suggest that diabetes promoted the progression of MI in vivo and in vitro via the inhibition of the Notch signaling pathway. Jagged1 may protect against MI in in vitro models by activating Notch signaling.

Salvianolic Acid Exerts Cardioprotection through Promoting Angiogenesis in Animal Models of Acute Myocardial Infarction: Preclinical Evidence

Radix Salviae miltiorrhizae, danshen root (danshen), is one of the widely used Chinese herbal medicines in clinics, containing rich phenolic compounds. Salvianolic acid is the main active compound responsible for the pharmacologic effects of danshen. Here, we aimed to evaluate the effects of salvianolic acid on cardioprotection through promoting angiogenesis in experimental myocardial infarction. Studies of salvianolic acid in animal models of myocardial infarction were obtained from 6 databases until April 2016. The outcome measures were vascular endothelium growth factor (VEGF), blood vessel density (BVD), and myocardial infarct size. All the data were analyzed using Rev-Man 5.3 software. Ultimately, 14 studies were identified involving 226 animals. The quality score of studies ranged from 3 to 6. The meta-analysis of six studies showed significant effects of salvianolic acid on increasing VEGF expression compared with the control group (P < 0.01). The meta-analysis of the two salvianolic acid A studies and three salvianolic acid B studies showed significantly improving BVD compared with the control group (P < 0.01). The meta-analysis of five studies showed significant effects of salvianolic acid for decreasing myocardial infarct size compared with the control group (P < 0.01). In conclusion, these findings demonstrated that salvianolic acid can exert cardioprotection through promoting angiogenesis in animal models of myocardial infarction.

miR-22 regulates starvation-induced autophagy and apoptosis in cardiomyocytes by targeting p38α

microRNAs (miRNAs) are short noncoding RNAs that function in RNA silencing and post-transcriptional regulation of gene expression. They play critical regulatory roles in many cardiovascular diseases, including ischemia-induced cardiac injury. Here, we report microRNA-22, highly expressed in the heart, can protect cardiomyocytes from starvation-induced injury through promoting autophagy and inhibiting apoptosis. Quantitative real-time PCR (qPCR) demonstrated that the expression of miR-22 in starvation-treated neonatal rat cardiomyocytes (NRCMs) was markedly down-regulated. Over-expression of miR-22 significantly promoted starvation-induced autophagy and inhibited starvation-induced apoptosis in NRCMs. In contrast, reduction of miR-22 suppressed autophagy and accelerated apoptosis in starving NRCMs. Immunohistochemistry and TUNEL staining results also provided further evidence that miR-22 promoted autophagy and inhibited apoptosis in myocardial cells. Furthermore, both luciferase reporter assay and western blot analysis were performed to identify p38α as a direct target of miR-22. Taken together, miR-22 plays an important role in regulating autophagy and apoptosis in ischemic myocardium through targeting p38α. miR-22 may represent a potential therapeutic target for the treatment of ischemic heart diseases.

Cardioprotective effect of Salvianolic acid B on acute myocardial infarction by promoting autophagy and neovascularization and inhibiting apoptosis

OBJECTIVES

The aim of this study was to investigate the cardioprotective effect of salvianolic acid B (Sal B) on acute myocardial infarction (AMI) in rats and its potential mechanisms.

METHODS

The AMI model was established in rats to study the effect of Sal B on AMI. Haematoxylin-eosin (HE) staining was used to evaluate the pathological change in AMI rats. Immunofluorescence and TUNEL staining were used to detect autophagy and apoptosis of myocardial cells in hearts of AMI rats, respectively. Protein expression of apoptosis-related, autophagy-related and angiogenesis-related proteins were examined by Western blot.

KEY FINDINGS

Sal B attenuated myocardial infarction significantly compared with that of the model group. Rats administered with Sal B showed higher inhibition rate of infarction and lower infarct size than those of the model group. Moreover, Sal B decreased the serum levels of creatine kinase, lactate dehydrogenase and malondialdehyde, while increased such level of superoxide dismutase significantly compared with those of the model group. Sal B inhibited the expression of Bax, cleaved caspase-9 and cleaved PARP, while promoted the expression of Bcl-2, LC3-II, Beclin1 and VEGF.

CONCLUSIONS

Sal B has cardioprotective effect on AMI and Sal B may be a promising candidate for AMI treatment.