Early biventricular molecular responses to an acute myocardial infarction

MRTF-A alleviates myocardial ischemia reperfusion injury by inhibiting the inflammatory response and inducing autophagy

Myocardin-related transcription factor A (MRTF-A) has an inhibitory effect on myocardial infarction; however, the mechanism is not clear. This study reveals the mechanism by which MRTF-A regulates autophagy to alleviate myocardial infarct-mediated inflammation, and the effect of silent information regulator 1 (SIRT1) on the myocardial protective effect of MRTF-A was also verified. MRTF-A significantly decreased cardiac damage induced by myocardial ischemia. In addition, MRTF-A decreased NLRP3 inflammasome activity, and significantly increased the expression of autophagy protein in myocardial ischemia tissue. Lipopolysaccharide (LPS) and 3-methyladenine (3-MA) eliminated the protective effects of MRTF-A. Furthermore, simultaneous overexpression of MRTF-A and SIRT1 effectively reduced the injury caused by myocardial ischemia; this was associated with downregulation of inflammatory factor proteins and when upregulation of autophagy-related proteins. Inhibition of SIRT1 activity partially suppressed these MRTF-A-induced cardioprotective effects. SIRT1 has a synergistic effect with MRTF-A to inhibit myocardial ischemia injury through reducing the inflammation response and inducing autophagy.

SERPINB1 overexpression protects myocardial damage induced by acute myocardial infarction through AMPK/mTOR pathway

Background

SERPINB1 is involved in the development of a variety of diseases. The purpose of this study was to explore the effect of SERPINB1 on acute myocardial infarction (AMI).

Methods

Serum SERPINB1 level of AMI patients was measured for receiver operating characteristic curve analysis. The AMI rat model was constructed to observe myocardial damage, and the H9C2 cell oxygen glucose deprivation (OGD) model was constructed to detect cell viability. Transthoracic echocardiography was used to assess the cardiac function. TTC staining and HE staining were used to detect pathologic changes of myocardial tissues. The apoptosis of myocardial tissues and cells were measured by TUNLE staining and flow cytometry assay. CCK-8 assay to measure cell viability. SERPINB1 expression was measured by qRT-PCR. Protein expression was measured by western blot.

Results

The serum SERPINB1 level was down-regulated in AMI patients. AMI modeling reduced the SERPINB1 expression level, induced inflammatory cells infiltrated, and myocardial apoptosis. OGD treatment inhibited cell viability and promoted apoptosis. The AMPK/mTOR pathway was inhibited in AMI rats and OGD-treated H9C2 cells. Overexpression of SERPINB1 reduced infarct size and myocardial apoptosis of AMI rats, inhibited apoptosis of H9C2 cells, and activated AMPK/mTOR pathway. However, AMPK inhibitor Dorsomorphin reversed the protective effect of SERPINB1 on myocardial cells.

Conclusion

SERPINB1 overexpression relieved myocardial damage induced by AMI via AMPK/mTOR pathway.

Nobiletin alleviates the hypoxia/reoxygenation-induced damage in myocardial cells by modulating the miR-433/SIRT1 axis

The effect of nobiletin (NOB) on myocardial ischemia-reperfusion injury and the underlying mechanism were investigated in this study. Myocardial cells (H9c2) were cultured under hypoxia/reoxygenation (H/R) condition, followed by the treatment with NOB. Next, miR-433 overexpression or silencing was performed in H9c2 cells to further assess the efficacy of NOB. Cell viability and apoptosis were determined using MTT assays and flow cytometry, respectively. Our results demonstrated that NOB treatment led to the upregulation of SIRT1 and inhibited miR-433 expression in H9c2 cells. In addition, we found that miR-433 targeted and inhibited the expression of SIRT1. NOB treatment promoted cell viability and alleviated apoptosis in H9c2 cells. Thus, our findings indicate that NOB may relieve H/R-induced damage in H9c2 cells by modulating the miR-433/SIRT1 axis. PRACTICAL APPLICATIONS: MiR-433 targeted and inhibited the expression of SIRT1. NOB treatment promoted cell viability and alleviated apoptosis in H9c2 cells. Thus, our findings indicate that NOB could effectively relieve H/R-induced damage in H9c2 cells by modulating the miR-433/SIRT1 axis, suggesting that nobiletin may be a potential drug for the treatment of myocardial ischemia-reperfusion injury. Furthermore, this study also identified another potential therapeutic target, miR-433, for the treatment of myocardial ischemia-reperfusion injury.

Hemodynamic Support Using Percutaneous Transfemoral Impella 5.0 and Impella RP for Refractory Cardiogenic Shock

Acute myocardial infarction (AMI) resulting in cardiogenic shock continues to be a substantial source of morbidity and mortality despite advances in recognition and treatment. Prior to the advent of percutaneous and more durable left ventricular support devices, prompt revascularization with the addition of vasopressors and inotropes were the standard of care in the management of this critical population. Recent published studies have shown that in addition to prompt revascularization, unloading of the left ventricle with the placement of the Impella percutaneous axillary flow pump can lead to improvement in mortality. Parameters such as the cardiac power output (CPO) and pulmonary artery pulsatility index (PAPi), obtained through pulmonary artery catheterization, can help ascertain the productivity of right and left ventricular function. Utilization of these parameters can provide the information necessary to escalate support to the right ventricle with the insertion of an Impella RP or the left ventricle with the insertion of larger devices, which provide more forward flow. Herein, we present a case of AMI complicated by cardiogenic shock resulting in biventricular failure treated with the percutaneous insertion of an Impella RP and Impella 5.0 utilizing invasive markers of left and right ventricular function to guide the management and escalation of care.

Differential gene expression profiles in peripheral blood in Northeast Chinese Han people with acute myocardial infarction

This study aimed to use gene chips to investigate differential gene expression profiles in the occurrence and development of acute myocardial infarction (AMI). The study included 12 AMI patients and 12 healthy individuals. Total mRNA of peripheral bloodwas extracted and reversed-transcribed to cDNA for microarray analysis. After establishing two pools with three subjects each (3 AMI patients and 3 healthy individuals), the remaining samples were used for RT-qPCR to confirm the microarray data. From the microarray results, seven genes were randomly selected for RT-qPCR. RT-qPCR results were analyzed by the 2^-ΔΔCt method. Microarray analysis showed that 228 genes were up- regulated and 271 were down-regulated (p ≤ 0.05, |logFC| > 1). Gene ontology showed that these genes belong to 128 cellular components, 521 biological processes, and 151 molecular functions. KEGG pathway analysis showed that these genes are involved in 107 gene pathways. RT-qPCR results for the seven genes showed expression levels consistent with those obtained by microarray. Thus, microarray data could be used to select the pathogenic genes for AMI. Investigating the abnormal expression of these differentially expressed genes might suggest efficient strategies for the prevention, diagnosis, and treatment of AMI.

Down-regulation of lncRNA KCNQ1OT1 protects against myocardial ischemia/reperfusion injury following acute myocardial infarction

This study aimed to investigate the protective effects of long non-coding RNA KCNQ1OT1 against myocardial ischemia/reperfusion (I/R) injury following acute myocardial infarction, as well as its regulatory mechanism. We used the cardiac muscle H9c2 cells under condition of oxygen glucose deprivation followed by reperfusion (OGD/R) to induce myocardial I/R injury. Then H9C2 cells were transfected with si-NC, si-KCNQ1OT1, pc-NC, pc-KCNQ1OT1, si-AdipoR1 and si-AdipoR2, respectively. The myocardial cell viability and apoptosis were respectively detected. In addition, the expression levels of inflammatory factors, apoptosis-related proteins and p38 MAPK/NF-κB pathway-related proteins were detected. Besides, an inhibitor of p38 MAPK/NF-κB pathway SB203580 was used to treat cells to verify the relationship between KCNQ1OT1 and p38 MAPK/NF-κB pathway. The expression of KCNQ1OT1 was significantly up-regulated in OGD/R-induced myocardial H9C2 cells. The OGD/R-induced decreased cell viability and AdipoR1 expression could be reversed after suppression of KCNQ1OT1. In addition, suppression of KCNQ1OT1 reduced OGD/R-induced increased expressions of TNF-α, IL-6 and IL-1β and OGD/R-induced increased cell apoptosis, which were reversed after knockdown of AdipoR1. Besides, suppression of KCNQ1OT1 significantly down-regulated the OGD/R-induced increased expression of p-p38 and p-NF-κB, which were also reversed after knockdown of AdipoR1. Moreover, SB203580, an inhibitor of p38 MAPK/NF-κB signal pathway, could further enhance the inhibitory effects of KCNQ1OT1 suppression on the expression of p-p38, TNF-α, IL-6, IL-1β and p-NF-κB in OGD/R-induced myocardial H9C2 cells. Suppression of KCNQ1OT1 may prevent myocardial I/R injury following acute myocardial infarction via regulating AdipoR1 and involving in p38 MAPK/NF-κB signal pathway.