Future treatment strategies in ST-segment elevation myocardial infarction

Madecassoside mitigates acute myocardial infarction injury by activating the PKCB/SPARC signaling pathway

The current treatments and drugs of myocardial infarction (MI) remain insufficient. In recent years, natural products have garnered significant attention for their potential in treating cardiovascular diseases due to their availability and lower toxicity. Saponins, in particular, showed promising effects for cardiac protection. In this study, we investigated the therapeutic effects of the saponin compound madecassoside in the treatment of MI, and underlying molecular mechanisms. The acute MI model was established in male mice by ligation of the left anterior descending coronary artery. The mice were treated with madecassoside (20 mg· kg-1 ·d-1, i.g.) for 14 days. After sacrificing the mice, hearts were harvested for analysis. We showed that madecassoside administration significantly mitigated cardiac function decline in MI mice by promoting angiogenesis and inhibiting myocardial cell apoptosis and fibrosis. By conducting systems pharmacology and RNA sequencing, we demonstrated that madecassoside upregulated SPARC gene expression by activating protein kinase C-β (PKCB) that had a strong promoting effect on endothelial cell angiogenesis, thus playing a crucial protective role against MI. We showed that inhibition of SPARC gene significantly reduced madecassoside-stimulated migration and tube formation of endothelial cells in vitro; co-administration of the PKCB-specific inhibitor ruboxistaurin (10 mg· kg-1 ·d-1, i.g.) abolished the cardioprotective effect of madecassoside in MI mice, validating the critical role of the PKCB/SPARC signaling pathway. This study demonstrates that madecassoside regulates the PKCB/SPARC pathway, promotes the proliferation and regeneration of vascular endothelial cells, and effectively alleviates the symptoms of MI.

Efficacy and safety of salvianolate injection in treating acute myocardial infarction: a meta-analysis and systematic literature review

Purpose

Salvianolate for injection (SFI) is a widely used treatment for acute myocardial infarction (AMI). This study aims to assess the efficacy and safety of SFI in treating AMI by synthesizing evidence from published randomized controlled trials (RCTs).

Methods

Seven databases were searched for relevant RCTs published up to 1 July 2024. Two investigators independently conducted the literature searches, data extraction, and quality assessment. Subgroup and sensitivity analyses were performed to address potential heterogeneity. Data analyses were conducted using RevMan 5.4 software.

Result

Thirty RCTs with a total of 3,931 participants were included in the study and analyzed. The results revealed that SFI significantly reduced major adverse cardiac events (MACEs) (RR = 0.34, 95% CI: 0.24 to 0.49, p < 0.05). In addition, SFI lowered creatine kinase-MB (CK-MB) (MD = -5.65, 95% CI: -9.55 to -1.76, p < 0.05) and improved left ventricular ejection fraction (LVEF) (MD = 6.2, 95% CI: 4.82 to 7.57, p < 0.05). Further reductions were observed in C-reactive protein (CRP) (MD = -6.17, 95% CI: -8.11 to -4.23, p < 0.05), malondialdehyde (MDA) (MD = -1.95, 95% CI: -2.08 to -1.83, p < 0.05), and endothelin-1 (ET-1) (MD = -12.27, 95% CI: -17.13 to -7.40, p < 0.05). The incidence of adverse events did not significantly differ between the EG and CG [RR = 0.74, 95% CI: 0.42 to 1.33, p = 0.32].

Conclusion

This study suggests that SFI may be a promising alternative therapy for treating AMI without increasing the risk of adverse events. However, our findings may be limited by the quality of the existing studies. High-quality RCTs are needed to provide more robust evidence.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42024567279.

Effects of different doses of tirofiban combined with dual antiplatelet drugs on platelet indices, vascular endothelial function, and major adverse cardiovascular events in patients with acute ST-segment elevated myocardial infarction undergoing percutaneous coronary intervention

This trial targeted to analyze the effects of different doses of tirofiban combined with dual antiplatelet drugs on platelet indices, vascular endothelial function, and major adverse cardiovascular events (MACE) in patients with acute ST-segment elevated myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI). A total of 180 patients with STEMI who underwent PCI were divided into Group A, Group B, and Group C (60 cases per group). Group A was given conventional medication, and Groups B and C were given a standard dose (10 μg/kg) and a high dose (20 μg/kg) of tirofiban on the basis of Group A, respectively. Thrombolysis in myocardial infarction (TIMI) myocardial perfusion grade and TIMI blood flow grade were compared. Myocardial enzymes, platelet indices, vascular endothelial function, inflammatory factors, and cardiac function indices were detected. In-hospital bleeding events and follow-up MACE were recorded. After PCI, Group C had a higher number of TIMI myocardial perfusion grade III and TIMI blood flow grade III versus Group A. Group C achieved the greatest changes in myocardial enzymes, platelet indices, vascular endothelial function-related factors, inflammatory factors, and cardiac function indices, followed by Group B and Group A. The incidence of bleeding events was higher in Group C than in Group A, and that of MACE in Group C was lower than in Group A. The addition of high-dose tirofiban to PCI and dual antiplatelet drugs for STEMI patients can improve myocardial blood perfusion, cardiac function, and vascular endothelial function, inhibit platelet activation and aggregation, and reduce the occurrence of MACE.

Gene Therapy for Cardiovascular Disease: Clinical Perspectives

Cardiovascular disease (CVD) stands as one of the leading causes of death in the United States, with its prevalence steadily on the rise. Traditional therapeutic approaches, such as pharmacological treatment, cardiovascular intervention, and surgery, have inherent limitations. In response to these challenges, cardiac gene therapy has emerged as a promising alternative for treating CVD patients. However, several obstacles persist, including the low efficiency of gene transduction, immune reactions to vectors or transduced cells, and the occurrence of off-target effects. While preclinical research has demonstrated significant success in various CVD model in both small and large animals, the translation of these findings to clinical applications has, for the most part, yielded disappointing results, except for some early, albeit small, trials. This review aims to provide a comprehensive summary of recent preclinical and clinical studies on gene therapy for various CVDs. Additionally, we discuss the existing limitations and challenges that hinder the widespread clinical application of cardiac gene therapy.

Intracoronary thrombolysis in ST-elevation myocardial infarction: a systematic review and meta-analysis

BACKGROUND

Despite restoration of epicardial blood flow in acute ST-elevation myocardial infarction (STEMI), inadequate microcirculatory perfusion is common and portends a poor prognosis. Intracoronary (IC) thrombolytic therapy can reduce microvascular thrombotic burden; however, contemporary studies have produced conflicting outcomes.

OBJECTIVES

This meta-analysis aims to evaluate the efficacy and safety of adjunctive IC thrombolytic therapy at the time of primary percutaneous coronary intervention (PCI) among patients with STEMI.

METHODS

Comprehensive literature search of six electronic databases identified relevant randomised controlled trials. The primary outcome was major adverse cardiac events (MACE). The pooled risk ratio (RR) and weighted mean difference (WMD) with a 95% CI were calculated.

RESULTS

12 studies with 1915 patients were included. IC thrombolysis was associated with a significantly lower incidence of MACE (RR=0.65, 95% CI 0.51 to 0.82, I2=0%, p<0.0004) and improved left ventricular ejection fraction (WMD=1.87; 95% CI 1.07 to 2.67; I2=25%; p<0.0001). Subgroup analysis demonstrated a significant reduction in MACE for trials using non-fibrin (RR=0.39, 95% CI 0.20 to 0.78, I2=0%, p=0.007) and moderately fibrin-specific thrombolytic agents (RR=0.62, 95% CI 0.47 to 0.83, I2=0%, p=0.001). No significant reduction was observed in studies using highly fibrin-specific thrombolytic agents (RR=1.10, 95% CI 0.62 to 1.96, I2=0%, p=0.75). Furthermore, there were no significant differences in mortality (RR=0.91; 95% CI 0.48 to 1.71; I2=0%; p=0.77) or bleeding events (major bleeding, RR=1.24; 95% CI 0.47 to 3.28; I2=0%; p=0.67; minor bleeding, RR=1.47; 95% CI 0.90 to 2.40; I2=0%; p=0.12).

CONCLUSION

Adjunctive IC thrombolysis at the time of primary PCI in patients with STEMI improves clinical and myocardial perfusion parameters without an increased rate of bleeding. Further research is needed to optimise the selection of thrombolytic agents and treatment protocols.

Protective effect of esculentoside A against myocardial infarction via targeting C-X-C motif chemokine receptor 2

Myocardial infarction (MI) is the primary cause of cardiac mortality. Esculentoside A (EsA), a triterpenoid saponin, has anti-inflammatory and antioxidant activities. However, its effect on MI remains unknown. In this study, the protective effect and mechanisms of EsA against MI were investigated. EsA significantly alleviated hypoxia-induced HL-1 cell injury, including increasing cell viability, inhibiting reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP) and lactate dehydrogenase (LDH) leakage. In mouse MI model by left coronary artery (LAD) ligating, EsA obviously restored serum levels of creatine kinase isoenzymes (CK-MB), cardiac troponin I (cTnI), superoxide dismutase (SOD) and malondialdehyde (MDA). In addition, the cardioprotective effect of EsA was further confirmed by infarct size, electrocardiogram and echocardiography. Mechanistically, the targeted binding relationship between EsA and C-X-C motif chemokine receptor 2 (CXCR2) was predicted by molecular docking and dynamics, and validated by small molecule pull-down and surface plasmon resonance tests. EsA inhibited CXCR2 level both in vitro and in vivo, correspondingly alleviated oxidative stress by suppressing NOX1 and NOX2 and relieved inflammation through inhibiting p65 and p-p65. It demonstrated that EsA could play a cardioprotective role by targeting CXCR2. However, the effect of EsA against MI was abolished in combination with CXCR2 overexpression both in vitro and in vivo. This study revealed that EsA showed excellent cardioprotective activities by targeting CXCR2 to alleviate oxidative stress and inflammation in MI. EsA may function as a novel CXCR2 inhibitor and a potent candidate for the prevention and intervention of MI in the future.

Intracoronary pharmacological therapy versus aspiration thrombectomy in STEMI (IPAT-STEMI): A systematic review and meta-analysis of randomized trials

BACKGROUND

Thrombus load in STEMI patients remains a challenge in practice. It aggravates coronary obstruction leading to impaired myocardial perfusion, worsened cardiac function, and adverse clinical outcomes. Various strategies have been advocated to reduce thrombus burden.

OBJECTIVES

This meta-analysis aimed to evaluate the effectiveness of intracoronary-administered thrombolytics or glycoprotein IIb/IIIa inhibitors (GPI) in comparison with aspiration thrombectomy (AT) as an adjunct to percutaneous coronary intervention (PCI) among patients presenting with ST-segment elevation myocardial infarction (STEMI).

METHODS

A comprehensive literature search for randomized trials that compared intracoronary-administered thrombolytics or GPI with AT in STEMI patients who underwent PCI, was conducted using various databases (e.g., MEDLINE, EMBASE, CENTRALE). Primary outcome was procedural measures (e.g., TIMI flow grade 3, TIMI myocardial perfusion grade (TMPG) 3, Myocardial blush grade (MBG) 2/3, ST-segment resolution (STR)).

RESULTS

Twelve randomized trials enrolled 1,466 patients: 696 were randomized to intracoronary-administered pharmacological interventions and 553 to AT. Patients randomized to PCI alone were excluded. Thrombolytics significantly improved TIMI flow grade 3 (odds ratio = 3.71, 95% CI: 1.85-7.45), complete STR (odds ratio = 3.64, 95% CI: 1.60-8.26), and TMPG 3 (odds ratio = 5.31, 95% CI: 2.48-11.36). Thrombolytics significantly reduced major adverse cardiovascular events (MACE) (odds ratio = 0.29, 95% CI: 0.13-0.65) without increasing bleeding risk. Trial sequential analysis assessment confirmed the superiority of thrombolytics for the primary outcome. Intracoronary GPI, either alone or combined with AT, did not improve procedural or clinical outcomes.

CONCLUSIONS

Compared with AT, intracoronary-administered thrombolytics significantly improved myocardial perfusion and MACE in STEMI patients.

Wearable Pressure Sensors for Pulse Wave Monitoring

Cardiovascular diseases remain the leading cause of death worldwide. The rapid development of flexible sensing technologies and wearable pressure sensors have attracted keen research interest and have been widely used for long-term and real-time cardiovascular status monitoring. Owing to compelling characteristics, including light weight, wearing comfort, and high sensitivity to pulse pressures, physiological pulse waveforms can be precisely and continuously monitored by flexible pressure sensors for wearable health monitoring. Herein, an overview of wearable pressure sensors for human pulse wave monitoring is presented, with a focus on the transduction mechanism, microengineering structures, and related applications in pulse wave monitoring and cardiovascular condition assessment. The conceptualizations and methods for the acquisition of physiological and pathological information related to the cardiovascular system are outlined. The biomechanics of arterial pulse waves and the working mechanism of various wearable pressure sensors, including triboelectric, piezoelectric, magnetoelastic, piezoresistive, capacitive, and optical sensors, are also subject to systematic debate. Exemple applications of pulse wave measurement based on microengineering structured devices are then summarized. Finally, a discussion of the opportunities and challenges that wearable pressure sensors face, as well as their potential as a wearable intelligent system for personalized healthcare is given in conclusion.

Treatment delay and reperfusion management of acute ST-segment elevation myocardial infarction: analysis of the China STEMI Care Project Phase 1

BACKGROUND

The China ST-segment elevation myocardial infarction (STEMI) Care Project (CSCAP) was launched in 2011 to address the problems of insufficient reperfusion and long treatment delay in STEMI care in China.

AIM

To describe the baseline status of STEMI emergency care in Tertiary PCI Hospitals using Phase 1 (CSCAP-1) data.

DESIGN

CSCAP-1 is a prospective multi-center STEMI registry.

METHODS AND RESULTS

A total of 4191 patients with symptom onset within 12 or 12-36 h requiring primary percutaneous coronary intervention (PCI), were enrolled from 53 tertiary PCI hospitals in 14 provinces, municipalities, and autonomous regions of China in CSCAP-1. Among them, 49.0% were self-transported to the hospital, 26.5% were transferred to the hospital by calling the emergency medical services directly, and 24.5% were transferred from other hospitals. In patients with symptom onset within 12 h, 83.2% received primary PCI, 5.9% received thrombolysis and 10.9% received conservative medications. The median door-to-balloon time was 115 (85-170) min and the median door-to-needle time for in-hospital thrombolysis was 80 (50-135) min. The overall in-hospital all-cause mortality was 2.4%, while it was 5.3% in the non-reperfusion group and 2.1% in the reperfusion group (P < 0.001).

CONCLUSION

Although a long treatment delay and a high proportion of patients transporting themselves to the hospital were observed, trends were positive with greater adoption of primary PCI and lower in-hospital mortality in tertiary hospitals in China. Our results provided important information for further integrated STEMI network construction in China.

Dexmedetomidine exerts cardioprotective effect through miR-146a-3p targeting IRAK1 and TRAF6 via inhibition of the NF-κB pathway

BACKGROUND

Myocardial ischemia/reperfusion (I/R) injury is a common cause of mortality. Cardiac miR-146a is emerging as a potent regulator of myocardial function. Dexmedetomidine preconditioning provides cardioprotective effects, of which mechanisms related to miR-146a-3p are unclear.

METHODS

A myocardial I/R model in rats and a cellular anoxia/reoxygenation (A/R) model in H9C2 cells were established and preconditioned with dexmedetomidine or not. H9C2 cells were transfected with mimics, inhibitor, or negative controls of miR-146a-3p, and siRNAs of IRAK1 or TRAF6. Relative expressions of miR-146a-3p were determined by quantitative real-time polymerase chain reaction. The apoptosis rates and reactive oxygen species (ROS) levels in H9C2 cells were examined by flow cytometry. Protein expressions of IRAK1, TRAF6, cleaved Caspase-3, BAX, BCL-2, NF-κB p65, phosphorylated NF-κB p65 (p-NF-κB p65), IκBα, and phosphorylated IκBα (p-IκBα) in H9C2 cells were detected by Western blot.

RESULTS

Dexmedetomidine decreased myocardial infarction size and apoptosis rates of H9C2 cells. Dexmedetomidine upregulated expression of miR-146a-3p. Dexmedetomidine significantly decreased protein expressions of IRAK1, TRAF6, cleaved Caspase-3, BAX, and NF-κB p65, but increased expressions of BCL-2 in H9C2 cells. miR-146a-3p overexpression strengthened the anti-apoptotic effect induced by dexmedetomidine in H9C2 cells via decreasing protein levels of IRAK1, TRAF6, cleaved Caspase-3, BAX, NF-κB p65, p-NF-κB p65, and p-IκBα and increasing protein level of BCL-2. Downregulation of miR-146a-3p reversed the changes in these proteins in H9C2 cells. Expressions of NF-κB p65 and p-NF-κB p65 were further decreased following knockdown of IRAK1 or TRAF6. ROS emission was significantly increased after A/R, while significantly decreased following dexmedetomidine preconditioning in H9C2 cells transfected with siIRAK1 or siTRAF6.

CONCLUSION

miR-146a-3p targeting IRAK1 and TRAF6 through inhibition of NF-κB signaling pathway and ROS emission is involved in cardioprotection induced by dexmedetomidine pretreatment.

Inotropic agents and vasodilator strategies for the treatment of cardiogenic shock or low cardiac output syndrome

BACKGROUND

Cardiogenic shock (CS) and low cardiac output syndrome (LCOS) are potentially life-threatening complications of acute myocardial infarction (AMI), heart failure (HF) or cardiac surgery. While there is solid evidence for the treatment of other cardiovascular diseases of acute onset, treatment strategies in haemodynamic instability due to CS and LCOS remains less robustly supported by the given scientific literature. Therefore, we have analysed the current body of evidence for the treatment of CS or LCOS with inotropic and/or vasodilating agents. This is the second update of a Cochrane review originally published in 2014.

OBJECTIVES

Assessment of efficacy and safety of cardiac care with positive inotropic agents and vasodilator agents in CS or LCOS due to AMI, HF or after cardiac surgery.

SEARCH METHODS

We conducted a search in CENTRAL, MEDLINE, Embase and CPCI-S Web of Science in October 2019. We also searched four registers of ongoing trials and scanned reference lists and contacted experts in the field to obtain further information. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials (RCTs) enrolling patients with AMI, HF or cardiac surgery complicated by CS or LCOS.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures according to Cochrane standards.

MAIN RESULTS

We identified 19 eligible studies including 2385 individuals (mean or median age range 56 to 73 years) and three ongoing studies. We categorised studies into 11 comparisons, all against standard cardiac care and additional other drugs or placebo. These comparisons investigated the efficacy of levosimendan versus dobutamine, enoximone or placebo; enoximone versus dobutamine, piroximone or epinephrine-nitroglycerine; epinephrine versus norepinephrine or norepinephrine-dobutamine; dopexamine versus dopamine; milrinone versus dobutamine and dopamine-milrinone versus dopamine-dobutamine. All trials were published in peer-reviewed journals, and analyses were done by the intention-to-treat (ITT) principle. Eighteen of 19 trials were small with only a few included participants. An acknowledgement of funding by the pharmaceutical industry or missing conflict of interest statements occurred in nine of 19 trials. In general, confidence in the results of analysed studies was reduced due to relevant study limitations (risk of bias), imprecision or indirectness. Domains of concern, which showed a high risk in more than 50% of included studies, encompassed performance bias (blinding of participants and personnel) and bias affecting the quality of evidence on adverse events. All comparisons revealed uncertainty on the effect of inotropic/vasodilating drugs on all-cause mortality with a low to very low quality of evidence. In detail, the findings were: levosimendan versus dobutamine (short-term mortality: RR 0.60, 95% CI 0.36 to 1.03; participants = 1701; low-quality evidence; long-term mortality: RR 0.84, 95% CI 0.63 to 1.13; participants = 1591; low-quality evidence); levosimendan versus placebo (short-term mortality: no data available; long-term mortality: RR 0.55, 95% CI 0.16 to 1.90; participants = 55; very low-quality evidence); levosimendan versus enoximone (short-term mortality: RR 0.50, 0.22 to 1.14; participants = 32; very low-quality evidence; long-term mortality: no data available); epinephrine versus norepinephrine-dobutamine (short-term mortality: RR 1.25; 95% CI 0.41 to 3.77; participants = 30; very low-quality evidence; long-term mortality: no data available); dopexamine versus dopamine (short-term mortality: no deaths in either intervention arm; participants = 70; very low-quality evidence; long-term mortality: no data available); enoximone versus dobutamine (short-term mortality RR 0.21; 95% CI 0.01 to 4.11; participants = 27; very low-quality evidence; long-term mortality: no data available); epinephrine versus norepinephrine (short-term mortality: RR 1.81, 0.89 to 3.68; participants = 57; very low-quality evidence; long-term mortality: no data available); and dopamine-milrinone versus dopamine-dobutamine (short-term mortality: RR 1.0, 95% CI 0.34 to 2.93; participants = 20; very low-quality evidence; long-term mortality: no data available). No information regarding all-cause mortality were available for the comparisons milrinone versus dobutamine, enoximone versus piroximone and enoximone versus epinephrine-nitroglycerine.

AUTHORS' CONCLUSIONS

At present, there are no convincing data supporting any specific inotropic or vasodilating therapy to reduce mortality in haemodynamically unstable patients with CS or LCOS. Considering the limited evidence derived from the present data due to a high risk of bias and imprecision, it should be emphasised that there is an unmet need for large-scale, well-designed randomised trials on this topic to close the gap between daily practice in critical care of cardiovascular patients and the available evidence. In light of the uncertainties in the field, partially due to the underlying methodological flaws in existing studies, future RCTs should be carefully designed to potentially overcome given limitations and ultimately define the role of inotropic agents and vasodilator strategies in CS and LCOS.

Efficacy and safety of intracoronary prourokinase during percutaneous coronary intervention in treating ST-segment elevation myocardial infarction patients: a randomized, controlled study

Background

Prourokinase is a single-chain plasminogen activator presenting with fewer hemorrhagic complications and reduced reocclusion rate compared with the conventional fibrinolytic agents in patients with coronary artery disease. However, prourokinase intracoronary injection during PCI for treating patients with ST-segment elevation myocardial infarction (STEMI) is rarely investigated. Therefore, this study aimed to evaluate the efficacy and safety of intracoronary prourokinase during the percutaneous coronary intervention (PCI) in treating STEMI patients.

Methods

Fifty STEMI patients who underwent primary PCI were consecutively enrolled and randomly assigned to intracoronary prourokinase group (N = 25) or control group (N = 25). During the primary PCI procedure, patients in the intracoronary prourokinase group received 10 ml prourokinase injection, while patients in control group received 10 ml saline injection as control. The primary endpoints were coronary physiological indexes, the secondary endpoints were angiographic assessments, myocardial infarct size/reperfusion assessment, cardiac function evaluations, major adverse coronary events (MACEs) and hemorrhagic complications. All patients were followed up for 3 months.

Results

Post PCI, the index of microcirculatory resistance (IMR) was decreased in intracoronary prourokinase group than that in control group (34.56 ± 7.48 vs. 49.00 ± 8.98, P < 0.001), while no difference of coronary flow reserve (CFR) (2.01 ± 0.32 vs. 1.88 ± 0.23, P = 0.267) or fractional flow reserve (FFR) (0.89 ± 0.05 vs. 0.87 ± 0.04, P = 0.121) was found between the two groups. The thrombolysis in myocardial infarction myocardial perfusion grade (TMPG) (P = 0.024), peak values of creatine kinase (CK) (P = 0.028), CK isoenzyme-MB (CK-MB) (P = 0.016), cardiac troponin I (cTnI) (P = 0.032) and complete ST-segment resolution (STR) (P = 0.005) were better in intracoronary prourokinase group compared with control group. At 3-months post PCI, left ventricular ejection fraction (LVEF) and wall motion score index (WMSI) were higher, while left ventricular end-diastolic diameter (LVEDd) was lower in intracoronary prourokinase group compared with control group (all P < 0.05). There was no difference in hemorrhagic complication or total MACE between the two groups.

Conclusion

Intracoronary prourokinase during PCI is more efficient and equally tolerant compared with PCI alone in treating STEMI patients.

Trial registration

Chinese Clinical Trial Registry ChiCTR1800016207. Prospectively registered.

Mitochondrial Quality Control: Role in Cardiac Models of Lethal Ischemia-Reperfusion Injury

The current standard of care for acute myocardial infarction or 'heart attack' is timely restoration of blood flow to the ischemic region of the heart. While reperfusion is essential for the salvage of ischemic myocardium, re-introduction of blood flow paradoxically kills (rather than rescues) a population of previously ischemic cardiomyocytes-a phenomenon referred to as 'lethal myocardial ischemia-reperfusion (IR) injury'. There is long-standing and exhaustive evidence that mitochondria are at the nexus of lethal IR injury. However, during the past decade, the paradigm of mitochondria as mediators of IR-induced cardiomyocyte death has been expanded to include the highly orchestrated process of mitochondrial quality control. Our aims in this review are to: (1) briefly summarize the current understanding of the pathogenesis of IR injury, and (2) incorporating landmark data from a broad spectrum of models (including immortalized cells, primary cardiomyocytes and intact hearts), provide a critical discussion of the emerging concept that mitochondrial dynamics and mitophagy (the components of mitochondrial quality control) may contribute to the pathogenesis of cardiomyocyte death in the setting of ischemia-reperfusion.

Impact of direct stenting on clinical outcomes for small vessel coronary artery disease in patients undergoing primary percutaneous coronary intervention for ST-elevation myocardial infarction

Introduction

Direct stenting (DS) is associated with improved markers of reperfusion during primary percutaneous coronary intervention (PPCI) for ST-elevation myocardial infarction (STEMI). However, data evaluating its impact in small vessel coronary artery disease (CAD) are lacking.

Aim

To compare DS and conventional stenting (CS) for small vessel CAD on clinical outcomes of patients with STEMI undergoing PPCI.

Material and methods

A cohort of 616 STEMI patients treated with DS (202 patients) or CS (414 patients) in small vessel (≤ 2.75 mm) lesions was retrospectively analyzed. The primary endpoint was to compare the occurrence of major adverse cardiac events (MACE) between groups during 2-year follow-up. The secondary end points included in-hospital target lesion revascularization (TLR) and in-hospital death.

Results

The primary end-point, MACEs, occurred in 9.2% in the DS group and 12.3% in the CS group (p > 0.05). The rates of TLR, myocardial infarction (MI) and target vessel revascularization (TVR) were not significantly different between groups (p > 0.05). The stent thrombosis (ST) rate was significantly lower in the DS group (1.0% vs. 4.2%, p = 0.04) at 2 years. However, DS was not found to be an independent predictor of ST in multivariate analysis. There were no significant differences in in-hospital rates of death and TLR. The DS compared to CS resulted in greater rates of postprocedural TIMI grade 3 flow, and lower risk of edge dissection. The procedure time, radiation exposure and contrast administration were found to be significantly lower in the DS group.

Conclusions

In selected patients with STEMI undergoing PPCI for small vessel CAD, DS is not only safe and feasible but also reduces ST rates, contrast load, and procedural and radiation exposure time.

Microvesicles Derived from Human Embryonic Neural Stem Cells Inhibit the Apoptosis of HL-1 Cardiomyocytes by Promoting Autophagy and Regulating AKT and mTOR via Transporting HSP-70

Myocardial reperfusion injury (MRI) induced by cardiomyocyte apoptosis plays an important role in the pathogenesis of a variety of cardiovascular diseases. New MRI treatments involving stem cells are currently being developed because these cells may exert their therapeutic effects primarily through paracrine mechanisms. Microvesicles (MVs) are small extracellular vesicles that have become the key mediators of intercellular communication. MVs derived from stem cells have been reported to play an important role in MRI. In this article, we attempted to explore the mechanisms by which MVs derived from human embryonic neural stem cells (hESC-NSC-derived MVs) rescue MRI. hESCs were differentiated into NSCs, and MVs were isolated from their supernatants by ultracentrifugation. H₂O₂ was used to induce apoptosis in HL-1 cardiomyocytes. Cell viability was detected by using the CCK-8 assay, apoptosis was detected by Annexin V-FITC/PI staining, and apoptosis-related proteins and signalling pathway-related proteins were detected by western blot analysis. Autophagic flux was measured using the tandem fluorescent mRFG-GFP-LC3 assay. Transmission electron microscopy and western blot analysis were adopted to evaluate autophagy levels. hESC-NSC-derived MVs increased the autophagy and inhibited the apoptosis of HL-1 cells exposed to H₂O₂ for 3 h in a dose-dependent manner. Additionally, hESC-NSC-derived MVs contained high levels of heat shock protein 70 (HSP-70), which can increase the level of HSP-70 in cells. Moreover, the same effect could be achieved by heat shock preconditioning of HL-1 cells overexpressing HSP-70. The benefits of NSC-MVs may be due to the involvement of AKT and mTOR signalling pathways. Importantly, hESC-NSC-derived MVs stimulated the activation of the AKTand mTOR signalling pathway in those cells by transporting HSP-70. Our results suggest that hESC-NSC-derived MVs inhibit the apoptosis of HL-1 cardiomyocytes by promoting autophagy and regulating AKT and mTOR via transporting HSP-70. However, this hypothesis requires in vivo confirmation.

Protocol of the China ST-segment elevation myocardial infarction (STEMI) Care Project (CSCAP): a 10-year project to improve quality of care by building up a regional STEMI care network

INTRODUCTION

Successful ST-segment elevation myocardial infarction (STEMI) management is time-sensitive and is based on prompt reperfusion mainly to reduce patient mortality. It has evolved from a single hospital care to an integrated regional network approach over the last decades. This prospective study, named the China STEMI Care Project (CSCAP), aims to show how implementation of different types of integrated regional STEMI care networks can improve the reperfusion treatment rate, shorten the total duration of myocardial ischaemia and lead to mortality reduction step by step.

METHODS AND ANALYSIS

The CSCAP is a prospective, multicentre registry study of three phases. A total of 18 provinces, 4 municipalities and 2 autonomous regions in China were included. Patients who meet the third universal definition of myocardial infarction and the Chinese STEMI diagnosis and treatment guidelines are enrolled. Phase 1 (CSCAP-1) focuses on the in-hospital process optimisation of primary percutaneous coronary intervention (PPCI) hospitals, phase 2 (CSCAP-2) focuses on the PPCI hospital-based regional STEMI care network construction together with emergency medical services and adjacent non-PPCI hospitals, while phase 3 (CSCAP-3) focuses on the whole-city STEMI care network construction by promoting chest pain centre accreditation. Systematic data collection, key performance index assessment and subsequent improvement are implemented throughout the project to continuously improve the quality of STEMI care.

ETHICS AND DISSEMINATION

The study has been reviewed and approved by the Ethics Committee of Peking University First Hospital. Ranking reports of quality of care will be generated available to all participant affiliations. Results will be disseminated via peer-reviewed scientific journals and presentations at congresses.

TRIAL REGISTRATION NUMBER

NCT03821012.

Relationship between serum homocysteine levels and long-term outcomes in patients with ST-segment elevation myocardial infarction

BACKGROUND

The mortality of cardiovascular disease is constantly rising, and novel biomarkers help us predict residual risk. This study aimed to evaluate the predictive value of serum homocysteine (HCY) levels on prognosis in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

The 419 consecutive patients with STEMI, treated at one medical center, from March 2010 to December 2015 were retrospectively investigated. Peripheral blood samples were obtained within 24 h of admission and HCY concentrations were measured using an enzymatic cycling assay. The patients were divided into high HCY level (H-HCY) and low HCY level (L-HCY) groups. Short- and long-term outcomes were compared, as were age-based subgroups (patients aged 60 years and younger vs. those older than 60 years). Statistical analyses were mainly conducted by Student t-test, Chi-squared test, logistic regression, and Cox proportional-hazards regression.

RESULTS

The H-HCY group had more males (84.6% vs. 75.4%, P = 0.018), and a lower prevalence of diabetes (20.2% vs. 35.5%, P < 0.001), compared with the L-HCY group. During hospitalization, there were seven mortalities in the L-HCY group and 10 in the H-HCY group (3.3% vs. 4.8%, P = 0.440). During the median follow-up period of 35.8 (26.9-46.1) months, 33 (16.2%) patients in the L-HCY group and 48 (24.2%) in the H-HCY group experienced major adverse cardiovascular and cerebrovascular events (MACCE) (P = 0.120). History of hypertension (hazard ratio [HR]: 1.881, 95% confidence interval [CI]: 1.178-3.005, P = 0.008) and higher Killip class (HR: 1.923, 95% CI: 1.419-2.607, P < 0.001), but not HCY levels (HR: 1.007, 95% CI: 0.987-1.027, P = 0.507), were significantly associated with long-term outcomes. However, the subgroup analysis indicated that in older patients, HCY levels were significantly associated with long-term outcomes (HR: 1.036, 95% CI: 1.011-1.062, P = 0.005).

CONCLUSION

Serum HCY levels did not independently predict in-hospital or long-term outcomes in patients with STEMI; however, among elderly patients with STEMI, this study revealed a risk profile for late outcomes that incorporated HCY level.

Dexmedetomidine preconditioning attenuates ischemia/reperfusion injury in isolated rat hearts with endothelial dysfunction

BACKGROUND AND PURPOSES

Dexmedetomidine preconditioning (DP) can mimic pharmacological preconditioning and induce cardiac protection. There are controversies on the roles of coronary endothelia in cardioprotection of dexmedetomidine. Herein, we tested the hypothesis that protection of dexmedetomidine is not endothelial dependent in heart against myocardial ischemia/reperfusion (I/R) injury.

METHODS

Langendorff-perfused rat hearts were pretreated by 60 mM of potassium to produce endothelial dysfunction (ED), then medicated with dexmedetomidine, and subsequently subjected to 30 min of global ischemia followed by 60 min of reperfusion. To investigate the cardioprotective effect of dexmedetomidine in heart with ED, isolated rat hearts were randomly divided into the following six groups: sham, I/R, DP, ED, ED + I/R, and ED + DP + I/R. Heart rates, left ventricular function, and coronary perfusion pressure were assessed for each heart. Infarct size was evaluated by triphenyltetrazolium chloride staining. High-sensitivity cardiac troponin T (hs-cTNT) of coronary flow perfusion was determined.

RESULTS

After the isolated hearts with pretreatment of 60 mM of potassium chloride, diastolic function of coronary endothelia in performance of response to histamine was significantly decreased (P < 0.05). DP attenuated I/R-induced infarct size of the left ventricle (P < 0.05) and decreased hs-cTNT (P < 0.05). Additionally, left ventricular developed pressure, +dp/dt_max, and -dp/dt_max were elevated in rat hearts pretreated with dexmedetomidine. Furthermore, dexmedetomidine-mediated cardiac protection against I/R injury was still remained in isolated hearts with coronary ED.

CONCLUSION

Continuous perfusion of 60 mM of potassium for 10 min can produce coronary ED in isolated rat hearts. Dexmedetomidine maintains its protective function against I/R injury in heart with coronary ED. Myocardial protection of dexmedetomidine is non-endothelial function dependent in alleviating I/R injury.

Impact of direct stenting on myocardial injury assessed by cardiac magnetic resonance imaging and prognosis in ST-elevation myocardial infarction

BACKGROUND

The results of studies investigating the clinical benefit of a direct stenting (DS) strategy in ST-elevation myocardial infarction (STEMI) are inconsistent and data regarding cardiac magnetic resonance (CMR) parameters of myocardial injury are lacking. The aim of this study was to investigate the effect of DS on myocardial damage in comparison to a conventional stenting technique (CS) with predilation in patients with reperfused STEMI.

METHODS

In a subanalysis of the randomized LIPSIA CONDITIONING trial (NCT02158468), STEMI patients were stratified according to the percutaneous coronary intervention technique into the DS (n = 171) or CS (n = 171) group after matching the patients for age (±5 years), gender, and TIMI flow before coronary intervention. Patients underwent CMR imaging within one week after infarction. Clinical outcome (death, reinfarction, hospitalization for heart failure) was assessed within 6 months after the index event.

RESULTS

Patients in the DS group had significantly lower infarct size (16 vs. 19% of left ventricular mass; p = 0.046) and microvascular obstruction with significant improvement of left ventricular parameters, which was associated with favorable clinical outcome with a lower incidence of heart failure hospitalizations (4% vs. 11%, p = 0.011) and mortality (5% vs. 12%, p = 0.034) as compared to patients with CS. In multivariate Cox regression analysis, DS was identified as an independent predictor of reduced mortality (HR 0.30, 95% CI 0.11-0.87, p = 0.026).

CONCLUSION

In patients with acute reperfused STEMI, DS is safe and feasible with a significant reduction of infarct size compared to CS and subsequent lower incidence of heart failure hospitalizations and mortality.

Alginate oligosaccharide alleviates myocardial reperfusion injury by inhibiting nitrative and oxidative stress and endoplasmic reticulum stress-mediated apoptosis

Alginate oligosaccharide (AOS) has recently demonstrated the ability to protect against acute doxorubicin cardiotoxicity and neurodegenerative disorders by inhibiting oxidative stress and endoplasmic reticulum (ER) stress-mediated apoptosis, which are both involved in myocardial ischemia/reperfusion (I/R) injury. In the present study, we investigated whether pretreatment with AOS protects against myocardial I/R injury in mice and explored potential cardioprotective mechanisms. AOS pretreatment significantly decreased the infarct size, reduced the cardiac troponin-I concentration, and ameliorated the cardiac dysfunction. Accompanied with the reduced cardiac injury, AOS pretreatment clearly decreased I/R-induced myocardial apoptosis. With regard to mechanism, AOS pretreatment markedly attenuated nitrative/oxidative stress, as evidenced by decreases in 3-nitrotyrosine content and superoxide generation, and downregulated inducible nitric oxide synthase, NADPH oxidase2, and 4-hydroxynonenal. Moreover, AOS pretreatment decreased myocardial apoptosis by inhibiting the ER stress-mediated apoptosis pathway, which is reflected by the downregulation of C/EBP homologous protein, glucose-regulated protein 78, caspase-12, and Bcl-2-associated X protein, and by the upregulation of the anti-apoptotic protein B-cell lymphoma-2. Collectively, these findings demonstrate that AOS renders the heart resistant to I/R injury, at least in part, by inhibiting nitrative/oxidative stress and ER stress-mediated apoptosis.

Attenuation of the hypoxia-induced miR-34a protects cardiomyocytes through maintenance of glucose metabolism

Ischemic injury in the heart is associated with death of cardiomyocytes and even after decades of research there is no appropriate therapeutic intervention to treat ischemic injury. The microRNA miR-34a is known to be induced in cardiomyocytes following ischemic injury. Another hallmark of ischemic injury is impaired glycolysis. The objective of the current study was to investigate the effects of short- and long-term exposure to hypoxia on miR-34a expression on apoptosis and regulation of key glycolysis metabolic enzymes. Both repeated short-term (30 min) burst of hypoxia with intermittent reoxygenation (30 min) as well as long-term (4 h) exposure to hypoxia followed by 6 h of reoxygenation robustly induced miR-34a levels. Hypoxia induced changes in cardiac permeability and localization of the channel protein connexin 34 as well as induced apoptosis as evident by levels of cleaved-caspase 3/7 and impaired cell proliferation. Hypoxia was also associated with decreased expression of key glycolytic enzymes hexokinase-1, hexokinase-2, glucose-6-phosphate-isomerase, and pyruvate dehydrogenase kinase 1. Attenuation of hypoxia-induced miR-34a by anti-miR-34a antagomir, but not a control antagomir, decreased miR-34a levels to those observed under normoxia and also inhibited apoptosis, potentially by rescuing expression of the key glycolytic enzymes. Cumulatively, our results establish that therapeutic targeting of miR-34a via antagomir might be a potent therapeutic mechanism to treat ischemic injury in the heart.

Plasma DPP4 activity is associated with no-reflow and major bleeding events in Chinese PCI-treated STEMI patients

Dipeptidyl peptidase-4 (DPP4) is an important regulator of incretins and inflammation, and it is involved in the pathophysiological process of myocardial infarction (MI). This study investigated the role of plasma DPP4 activity (DPP4a) in patients with ST-segment elevation myocardial infarction (STEMI) who had undergone percutaneous coronary intervention (PCI). We recruited 747 consecutive PCI-treated STEMI patients from a tertiary referral center from January 2014 to October 2015. The outcomes of interest were the rates of no-reflow, in-hospital major adverse cardiac or cerebrovascular events (iMACCE), in-hospital complications (IHC) and in-hospital major bleeding. The DPP4a was lower in STEMI patients compared with the controls (p < 0.0001). Multivariate logistic-regression analyses (adjusted for confounding variables) showed that a 1 U/L increase in DPP4a was associated with an increased rate of no-reflow events (odds ratio [OR]: 1.07; 95% CI: 1.02-1.11; p < 0.01) and a decreased rate of major bleeding events (OR: 0.90; 95% CI: 0.82-0.98; p = 0.02). There were no associations between DPP4a and either iMACCE or IHC. In conclusions, high levels of DPP4a are independently associated with an increased rate of no-reflow events and a decreased rate of major bleeding events in PCT-treated STEMI patients.

Pre-hospital alarm activation for STEMI patients undergoing primary percutaneous coronary intervention in the era of transradial procedures

BACKGROUND

Transradial access (TRA) improves outcome compared with trans-femoral access for the management of patients with acute coronary syndromes. In this setting, it is unknown whether the activation of a pre-hospital alarm system (PHAS) confers additional benefit for the prognosis of patients with ST-segment elevation myocardial infarction (STEMI).

MATERIALS AND METHODS

We retrospectively analyzed a cohort of patients with a first STEMI who underwent a primary percutaneous coronary intervention (PPCI) at a single center within a prospective cohort of acute coronary syndrome patients (SPUM-ACS). TRA was used in 85% of patients. We assessed how PHAS (n=165) vs. no-PHAS (n=166) activation was associated with the composite outcome of all-cause mortality and recurrence of myocardial infarction (MI) at 1-year follow-up. As secondary outcomes, the individual clinical endpoints were separately assessed for association.

RESULTS

Compared with no-PHAS patients, patients in the PHAS group were predominantly women, and presented more frequently with dyslipidemia and cardiac arrest. A significant reduction in the composite outcome of all-cause mortality and recurrent MI at 1-year was observed in the PHAS group, compared with no-PHAS (3.6% vs. 8.5%, p=0.027). When adjusted for age, sex and resuscitation status, PHAS activation remained associated with decreased all-cause mortality and recurrent MI (HR: 0.36 [95% CI: 0.13-0.95]; p=0.040).

CONCLUSIONS

This study suggests that the benefit of PHAS activation in STEMI patients undergoing PPCI persists also in the era of TRA.

Ischaemic conditioning and targeting reperfusion injury: a 30 year voyage of discovery

To commemorate the auspicious occasion of the 30th anniversary of IPC, leading pioneers in the field of cardioprotection gathered in Barcelona in May 2016 to review and discuss the history of IPC, its evolution to IPost and RIC, myocardial reperfusion injury as a therapeutic target, and future targets and strategies for cardioprotection. This article provides an overview of the major topics discussed at this special meeting and underscores the huge importance and impact, the discovery of IPC has made in the field of cardiovascular research.

Human relaxin gene expression delivered by bioreducible dendrimer polymer for post-infarct cardiac remodeling in rats

In consensus, myocardial infarction (MI) is defined as irreversible cell death secondary to prolonged ischemia in heart. The aim of our study was to evaluate the therapeutic potential of anti-fibrotic human Relaxin-expressing plasmid DNA with hypoxia response element (HRE) 12 copies (HR1) delivered by a dendrimer type PAM-ABP polymer G0 (HR1/G0) after MI on functional, hemodynamic, geometric, and cardiac extracellular matrix (ECM) remodeling in rats. HR1/G0 demonstrated significantly improved LV systolic function, hemodynamic parameters, and geometry on 1 wk and 4 wks after MI in rats, compared with I/R group. The resolution of regional wall motional abnormalities and the increased blood flow of infarct-related coronary artery supported functional improvements of HR1/G0. Furthermore, HR1/G0 polyplex showed favorable post-infarct cardiac ECM remodeling reflected on the favorable cardiac ECM compositions. Overall, this is the first study, which presented an advanced platform for the gene therapy that reverses adverse cardiac remodeling after MI with a HR1 gene delivered by a bioreducible dendrimer polymer in the cardiac ECM.

Impact of the Type of First Medical Contact within a Guideline-Conform ST-Elevation Myocardial Infarction Network: A Prospective Observational Registry Study

Aims

The impact of type of first medical contact (FMC) in the setting of a guideline conform metropolitan ST-elevation myocardial infarction (STEMI) network providing obligatory primary percutaneous coronary intervention (PCI) is unclear.

Methods and Results

3,312 patients were prospectively included between 2006 and 2012 into a registry accompanying the “Cologne Infarction Model” STEMI network, with 68.4% primarily presenting to emergency medical service (EMS), 17.6% to non-PCI-capable hospitals, and 14.0% to PCI-capable hospitals. Median contact-to-balloon time differed significantly by FMC with 89 minutes (IQR 72–115) for EMS, 107 minutes (IQR 85–148) for non-PCI- and 65 minutes (IQR 48–91) for PCI-capable hospitals (p < 0.001). TIMI-flow grade III and in-hospital mortality were 75.7% and 10.4% in EMS, 70.3% and 8.6% in non-PCI capable hospital and 84.4% and 5.6% in PCI-capable hospital presenters, respectively (p both < 0.01). The association of FMC with in-hospital mortality was not significant after adjustment for baseline characteristics, but risk of TIMI-flow grade < III remained significantly increased in patients presenting to non-PCI capable hospitals.

Conclusion

Despite differences in treatment delay by type of FMC in-hospital mortality did not differ significantly. The increased risk of TIMI-flow grade < III in patients presenting to non PCI-capable hospitals needs further study.

Heat shock protein 70 inhibits cardiomyocyte necroptosis through repressing autophagy in myocardial ischemia/reperfusion injury

Irreversible damage of cardiac function arisen from myocardial ischemia/reperfusion injury (MIRI) leads to an emerging challenge in the treatments of cardiac ischemic diseases. Molecular chaperone heat shock protein 70 (HSP70) attenuates heat-stimulated cell autophagy, apoptosis, and damage in the heart. Under specific conditions, autophagy may, directly or indirectly, induce cell death including necroptosis. Whether HSP70 inhibits cardiomyocyte necroptosis via suppressing autophagy during MIRI is unknown. In our study, HSP70 expression was opposite to necroptosis marker RIP1 and autophagy marker LC3A/B expression after myocardial ischemia/reperfusion (MIR) in vivo. Furthermore, in vitro primary rat cardiomyocytes mimicked MIRI by hypoxia/reoxygenation (H/R) treatment. Knockdown of HSP70 expression promoted cardiomyocyte autophagy and necroptosis following H/R treatment, while the increase tendency was downregulated by autophagy inhibitor 3-MA, showing that autophagy-induced necroptosis could be suppressed by HSP70. In summary, HSP70 downregulates cardiomyocyte necroptosis through suppressing autophagy during myocardial IR, revealing the novel protective mechanism of HSP70 and supplying a novel molecular target for the treatment of heart ischemic diseases.

Protection Efficacy of the Extract of Ginkgo biloba against the Learning and Memory Damage of Rats under Repeated High Sustained +Gz Exposure

Repeated high sustained positive Gz (+Gz) exposures are known for the harmful pathophysiological impact on the brain of rats, which is reflected as the interruption of normal performance of learning and memory. Interestingly, extract of Ginkgo biloba (EGb) has been reported to have neuroprotective effects and cognition-enhancing effects. In this study, we are interested in evaluating the protective effects of EGb toward the learning and memory abilities. Morris Water Maze Test (MWM) was used to evaluate the cognitive function, and the physiological status of the key components in central cholinergic system was also investigated. Our animal behavioral tests indicated that EGb can release the learning and memory impairment caused by repeated high sustained +Gz. Administration of EGb to rats can diminish some of the harmful physiological effects caused by repeated +Gz exposures. Moreover, EGb administration can increase the biological activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) but reduce the production of malondialdehyde (MDA). Taken together, our study showed that EGb can ameliorate the impairment of learning and memory abilities of rats induced by repeated high sustained +Gz exposure; the underlying mechanisms appeared to be related to the signal regulation on the cholinergic system and antioxidant enzymes system.

Postinfarct Left Ventricular Remodelling: A Prevailing Cause of Heart Failure

Heart failure is a chronic disease with high morbidity and mortality, which represents a growing challenge in medicine. A major risk factor for heart failure with reduced ejection fraction is a history of myocardial infarction. The expansion of a large infarct scar and subsequent regional ventricular dilatation can cause postinfarct remodelling, leading to significant enlargement of the left ventricular chamber. It has a negative prognostic value, because it precedes the clinical manifestations of heart failure. The characteristics of the infarcted myocardium predicting postinfarct remodelling can be studied with cardiac magnetic resonance and experimental imaging modalities such as diffusion tensor imaging can identify the changes in the architecture of myocardial fibers. This review discusses all the aspects related to postinfarct left ventricular remodelling: definition, pathogenesis, diagnosis, consequences, and available therapies, together with experimental interventions that show promising results against postinfarct remodelling and heart failure.

Human Mesenchymal Stem Cell Delivery System Modulates Ischemic Cardiac Remodeling With an Increase of Coronary Artery Blood Flow

Ways for extending the longevity of stem cells are imperative to attain diverse expected therapeutic effects. Here, we constructed a three-dimentional (3D) scaffold system for human mesenchymal stem cell (hMSC) delivery. Intramyocardial injections of porous PEI1.8k blended with poly(lactic-co-glycolic acid) (PLGA) (PLGA/PEI1.8k) (PPP) microparticles by physical electrostatic conjugation and structural entrapment of hMSCs demonstrated enhanced functional and geometric improvements on post-infarct cardiac remodeling in rats. In the hMSC-loaded PPP delivery, increases of coronary artery blood flow rate and in vivo engraftment rate as well as time-dependent functional, geometric, and pathologic findings reversing post-infarct cardiac remodeling account for improved left ventricular (LV) systolic function up to the level of sham thoracotomy group. This study expands our understanding by proving that increase of coronary artery blood flow augmented functional recovery of hMSC-loaded PPP delivery system after myocardial infarction (MI).

Peri-infarct zone pacing to prevent adverse left ventricular remodelling in patients with large myocardial infarction

AIMS

We sought to determine whether peri-infarct pacing prevents left ventricular (LV) remodelling and improves functional and clinical outcomes in patients with large first myocardial infarction (MI).

METHODS AND RESULTS

A total of 126 patients at 27 international sites within 10 days of onset of anterior or non-anterior MI with creatine phosphokinase >3000 U/L and QRS duration ≤120 ms were randomized 1:1:1 to dual-site biventricular pacing vs. single-site LV only pacing vs. non-implanted control. The primary endpoint was the echocardiographic core laboratory-assessed change in LV end-diastolic volume (ΔLVEDV) from baseline to 18 months between the pooled pacing therapy groups and the control group. ΔLVEDV increased by 15.3 ± 28.6 mL in the control group and by 16.7 ± 30.5 mL in the pooled pacing groups during follow-up (adjusted mean difference (95% CI) = 0.6 (-12.3, 13.5) mL, P = 0.92). There were also no significant between-group differences in the change in LV end-systolic volume or ejection fraction over time. Quality of life, as assessed by the Minnesota Living with Heart Failure (HF) and European Quality of Life-5 Dimension questionnaires and New York Heart Association class, was also similar between groups during 18-month follow-up. Six-minute walk distance improved during follow-up to an equal degree between groups, and there were no significant differences in the 18-month rates of death or HF hospitalization between the pooled pacing therapy vs. control groups (17.4 vs. 21.7% respectively, P = 0.59).

CONCLUSIONS

In the present multicentre, randomized trial, peri-infarct pacing did not prevent LV remodelling or improve functional or clinical outcomes during 18-month follow-up in patients with large first MI.

CLINICALTRIALSGOV IDENTIFIER

NCT01213251.

Human Engineered Heart Muscles Engraft and Survive Long Term in a Rodent Myocardial Infarction Model

RATIONALE

Tissue engineering approaches may improve survival and functional benefits from human embryonic stem cell-derived cardiomyocyte transplantation, thereby potentially preventing dilative remodeling and progression to heart failure.

OBJECTIVE

Assessment of transport stability, long-term survival, structural organization, functional benefits, and teratoma risk of engineered heart muscle (EHM) in a chronic myocardial infarction model.

METHODS AND RESULTS

We constructed EHMs from human embryonic stem cell-derived cardiomyocytes and released them for transatlantic shipping following predefined quality control criteria. Two days of shipment did not lead to adverse effects on cell viability or contractile performance of EHMs (n=3, P=0.83, P=0.87). One month after ischemia/reperfusion injury, EHMs were implanted onto immunocompromised rat hearts to simulate chronic ischemia. Bioluminescence imaging showed stable engraftment with no significant cell loss between week 2 and 12 (n=6, P=0.67), preserving ≤25% of the transplanted cells. Despite high engraftment rates and attenuated disease progression (change in ejection fraction for EHMs, -6.7±1.4% versus control, -10.9±1.5%; n>12; P=0.05), we observed no difference between EHMs containing viable and nonviable human cardiomyocytes in this chronic xenotransplantation model (n>12; P=0.41). Grafted cardiomyocytes showed enhanced sarcomere alignment and increased connexin 43 expression at 220 days after transplantation. No teratomas or tumors were found in any of the animals (n=14) used for long-term monitoring.

CONCLUSIONS

EHM transplantation led to high engraftment rates, long-term survival, and progressive maturation of human cardiomyocytes. However, cell engraftment was not correlated with functional improvements in this chronic myocardial infarction model. Most importantly, the safety of this approach was demonstrated by the lack of tumor or teratoma formation.

Febuxostat pretreatment attenuates myocardial ischemia/reperfusion injury via mitochondrial apoptosis

Background

Febuxostat is a selective inhibitor of xanthine oxidase (XO). XO is a critical source of reactive oxygen species (ROS) during myocardial ischemia/reperfusion (I/R) injury. Inhibition of XO is therapeutically effective in I/R injury. Evidence suggests that febuxostat exerts antioxidant effects by directly scavenging ROS. The present study was performed to investigate the effects of febuxostat on myocardial I/R injury and its underlying mechanisms.

Methods

We utilized an in vivo mouse model of myocardial I/R injury and an in vitro neonatal rat cardiomyocyte (NRC) model of hypoxia/reoxygenation (H/R) injury. Mice were randomized into five groups: Sham, I/R (I/R + Vehicle), I/R + FEB (I/R + febuxostat), AL + I/R (I/R + allopurinol) and FEB (febuxostat), respectively. The I/R + FEB mice were pretreated with febuxostat (5 mg/kg; i.p.) 24 and 1 h prior to I/R. NRCs received febuxostat (1 and 10 µM) at 24 and 1 h before exposure to hypoxia for 3 h followed by reoxygenation for 3 h. Cardiac function, myocardial infarct size, serum levels of creatine kinase (CK) and lactate dehydrogenase (LDH), and myocardial apoptotic index (AI) were measured in order to ascertain the effects of febuxostat on myocardial I/R injury. Hypoxia/reperfusion (H/R) injury in NRCs was examined using MTT, LDH leakage assay and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The underlying mechanisms were determined by measuring ROS production, mitochondrial membrane potential (ΔΨm), and expression of cytochrome c, cleaved caspases as well as Bcl-2 protein levels.

Results

Myocardial I/R led to an elevation in the myocardial infarct size, serum levels of CK and LDH, cell death and AI. Furthermore, I/R reduced cardiac function. These changes were significantly attenuated by pretreatment with febuxostat and allopurinol, especially by febuxostat. Febuxostat also protected the mitochondrial structure following myocardial I/R, inhibited H/R-induced ROS generation, stabilized the ΔΨm, alleviated cytosolic translocation of mitochondrial cytochrome C, inhibited activation of caspase-3 and -9, upregulated antiapoptotic proteins and downregulated proapoptotic proteins.

Conclusions

This study revealed that febuxostat pretreatment mediates the cardioprotective effects against I/R and H/R injury by inhibiting mitochondrial-dependent apoptosis.

Noncoding RNA in age-related cardiovascular diseases

Eukaryotic gene expression is tightly regulated transcriptionally and post-transcriptionally by a host of noncoding (nc)RNAs. The best-studied class of short ncRNAs, microRNAs, mainly repress gene expression post-transcriptionally. Long noncoding (lnc)RNAs, which comprise RNAs differing widely in length and function, can regulate gene transcription as well as post-transcriptional mRNA fate. Collectively, ncRNAs affect a broad range of age-related physiologic deteriorations and pathologies, including reduced cardiovascular vigor and age-associated cardiovascular disease. This review presents an update of our understanding of regulatory ncRNAs contributing to cardiovascular health and disease as a function of advancing age. We will discuss (1) regulatory ncRNAs that control aging-associated cardiovascular homeostasis and disease, (2) the concepts, approaches, and methodologies needed to study regulatory ncRNAs in cardiovascular aging and (3) the challenges and opportunities that age-associated regulatory ncRNAs present in cardiovascular physiology and pathology. This article is part of a Special Issue entitled "CV Aging".

Comparing Direct Stenting With Conventional Stenting in Patients With Acute Coronary Syndromes

Our aim was to compare direct stenting (DS) with conventional stenting (CS) in patients with acute coronary syndrome (ACS). We searched PubMed, EMBASE, and ISI web of science for eligible studies. Primary end point was major adverse cardiac events (MACEs) in short term. Secondary end points were 1-year mortality and after-procedural no-reflow phenomenon. Twelve trials in 8998 patients were included. The odds ratios (ORs) were pooled using the Mantel-Haenszel fixed effect model. Short-term MACEs were significantly reduced in the DS arm in contrast to the CS (5.00% vs 8.08%, DS vs CS, respectively, OR [95% confidence interval] = 0.61 [0.46-0.80], P = .0004). One-year mortality and after-procedural no-reflow phenomenon were significantly lower in the DS group. No heterogeneity was observed through I2 test ( Phet = .81, .89, and .77 for each end point, respectively). This meta-analysis demonstrated that in selected patients with ACS, DS is not only safe and feasible but also reduces short-term and 1-year mortality as well as the occurrence of after-procedural no-reflow phenomenon.

Long non-coding RNAs, a new important regulator of cardiovascular physiology and pathology

LncRNAs were previously considered to be the 'noise' of gene transcription having no biological functions, but now it has become evident that lncRNAs function as modulators of gene expression network. LncRNAs may regulate diverse gene expression levels which were roughly summarized to epigenetic, transcriptional and post-transcriptional levels. It has been clarified that some lncRNAs were expressed differentially in cardiovascular diseases, and aberrant changes of those lncRNAs were involved in the development of heart disorders. The role of lncRNAs in this process transcended the tradition of protein regulatory platform to be the orchestrator of cardiac sophisticated governing system of heart development, adaptation and pathological reaction. This review summarizes recent advances in the study of functions and mechanisms of lncRNAs in cardiovascular physiology and pathology. The regulatory roles of lncRNAs in cardiovascular diseases provide new strategy for interventional therapy of heart diseases.

Administration of erythropoietin in patients with myocardial infarction: does it make sense? An updated and comprehensive meta-analysis and systematic review

This systematic review with meta-analysis sought to determine protective effects of erythropoietin on clinical outcomes following percutaneous coronary intervention (PCI). Medline, Embase, Elsevier and Sciences online database as well as Google scholar literature were used for selecting appropriate studies with randomized controlled design. The effect sizes measured were odds ratio (OR) for categorical variables and weighted mean difference (WMD) with 95% confidence interval for calculating differences between mean values of duration of hospitalization in intervention and control groups. Values of P<0.1 for Q test or I(2)>50% indicated significant heterogeneity between the studies. The literature searches of all major databases retrieved 973 studies. After screening, a total of 15 trials that reported outcomes were identified. Pooled analysis was performed on left ventricular ejection fraction (WMD of -0.047; 95% CI: -0.912 to 0.819; P=0.9), left ventricular end diastolic volume (WMD of -0.363; 95% CI: -3.902 to 3.175; P=0.8), left ventricular end systolic volume (WMD of 0.346; 95% CI: -2.533 to 3.226; P=0.8), infarct size (WMD of -0.446; 95% CI: -2.352 to -1.460; P=0.6), stroke (OR of 2.1; 95% CI: 0.58 to 7.54; P=0.2), re-myocardial infarction (OR of 1.06; 95% CI: 0.52 to 2.185; P=0.8), heart failure (OR of 0.53; 95% CI: 0.259 to 1.105; P=0.09), mortality (OR of 0.56; 95% CI: 0.27 to 1.19; P=0.13), thrombosis (OR of 0.774; 95% CI: 0.41 to 1.45; P=0.4), major adverse cardiovascular events (OR of 0.926; 95% CI: 0.63 to 1.35; P=0.6). Short-term administration of EPO in patients with myocardial infarction (MI) undergoing PCI does not result in improvement in cardiac function, reduction of infarct size and all-cause mortality. Low dose EPO therapy may not be the choice of treatment for the patients with MI, while higher doses might be more effective.

Primary PCI: time to change focus from epicardial reperfusion towards protection of the microvasculature

Myocardial tissue perfusion remains compromised in 30-40% of patients with ST-segment elevation myocardial infarction (STEMI) despite restored epicardial patency after primary percutaneous coronary intervention (pPCI). This phenomenon is attributed to microvascular dysfunction secondary to numerous pathophysiological mechanisms, including distal embolisation of plaque and thrombus material. Its association with larger post-infarction myocardial necrosis, impaired left ventricular recovery, and worse clinical outcome illustrates the pertinence of a comprehensive armamentarium for the diagnosis, protection and treatment of microvascular dysfunction in STEMI patients. Current strategies to protect the microvasculature during pPCI are based on the assumption that distal embolisation of thrombotic and atheromatous debris is the main mechanism precipitating impaired myocardial tissue perfusion. However, recent findings suggest that this assumption is only true for the border zone of the ischaemic myocardium, whereas the infarct core consists of intramyocardial haemorrhage secondary to microvascular destruction, rather than obstruction. This observation has pertinent implications for contemporary and future adjuvant treatment strategies in STEMI patients. In this review, we provide an overview of the currently available armamentarium to assess the microvasculature, review contemporary strategies in pPCI to protect the myocardium, and discuss novel insights into microvascular pathophysiology that may help guide our focus from the coronary arteries to the microvasculature.

Injectable graphene oxide/hydrogel-based angiogenic gene delivery system for vasculogenesis and cardiac repair

The objective of this study was to develop an injectable and biocompatible hydrogel which can efficiently deliver a nanocomplex of graphene oxide (GO) and vascular endothelial growth factor-165 (VEGF) pro-angiogenic gene for myocardial therapy. For the study, an efficient nonviral gene delivery system using polyethylenimine (PEI) functionalized GO nanosheets (fGO) complexed with DNAVEGF was formulated and incorporated in the low-modulus methacrylated gelatin (GelMA) hydrogel to promote controlled and localized gene therapy. It was hypothesized that the fGOVEGF/GelMA nanocomposite hydrogels can efficiently transfect myocardial tissues and induce favorable therapeutic effects without invoking cytotoxic effects. To evaluate this hypothesis, a rat model with acute myocardial infarction was used, and the therapeutic hydrogels were injected intramyocardially in the peri-infarct regions. The secreted VEGF from in vitro transfected cardiomyocytes demonstrated profound mitotic activities on endothelial cells. A significant increase in myocardial capillary density at the injected peri-infarct region and reduction in scar area were noted in the infarcted hearts with fGOVEGF/GelMA treatment compared to infarcted hearts treated with untreated sham, GelMA and DNAVEGF/GelMA groups. Furthermore, the fGOVEGF/GelMA group showed significantly higher (p < 0.05, n = 7) cardiac performance in echocardiography compared to other groups, 14 days postinjection. In addition, no significant differences were noticed between GO/GelMA and non-GO groups in the serum cytokine levels and quantitative PCR based inflammatory microRNA (miRNA) marker expressions at the injected sites. Collectively, the current findings suggest the feasibility of a combined hydrogel-based gene therapy system for ischemic heart diseases using nonviral hybrid complex of fGO and DNA.

Reperfusion strategies in acute coronary syndromes

The appropriate timing of angiography to facilitate revascularization is essential to optimize outcomes in patents with ST-segment-elevation myocardial infarction and non-ST-segment-elevation acute coronary syndromes. Timely reperfusion of the infarct-related coronary artery in ST-segment-elevation myocardial infarction both with fibrinolysis or percutaneous coronary intervention minimizes myocardial damage, reduces infarct size, and decreases morbidity and mortality. Primary percutaneous coronary intervention is the preferred reperfusion method if it can be performed in a timely manner. Strategies to reduce health system-related delays in reperfusion include regionalization of ST-segment-elevation myocardial infarction care, performing prehospital ECGs, prehospital activation of the catheterization laboratory, bypassing geographically closer nonpercutaneous coronary intervention-capable hospitals, bypassing the percutaneous coronary intervention-capable hospital emergency department, and early and consistent availability of the catheterization laboratory team. With implementation of such strategies, there has been significant improvement in process measures, including door-to-balloon time. However, despite reductions in door-to-balloon times, there has been little change during the past several years in in-hospital mortality, suggesting additional factors including patient-related delays, optimization of tissue-level perfusion, and cardioprotection must be addressed to improve patient outcomes further. Early angiography followed by revascularization when appropriate also reduces rates of death, MI, and recurrent ischemia in patients with non-ST-segment-elevation acute coronary syndromes, with the greatest benefits realized in the highest risk patients. Among patients with non-ST-segment-elevation acute coronary syndromes with multivessel disease, choice of revascularization modality should be made as in stable coronary artery disease, with a goal of complete ischemic revascularization.

Comparison of two preclinical myocardial infarct models: coronary coil deployment versus surgical ligation

Background

Despite recent advances, myocardial infarction (MI) remains the leading cause of death worldwide. Pre-clinical animal models that closely mimic human MI are pivotal for a quick translation of research and swine have similarities in anatomy and physiology. Here, we compared coronary surgical ligation versus coil embolization MI models in swine.

Methods

Fifteen animals were randomly distributed to undergo surgical ligation (n = 7) or coil embolization (n = 8). We evaluated infarct size, scar fibrosis, inflammation, myocardial vascularization, and cardiac function by magnetic resonance imaging (MRI).

Results

Thirty-five days after MI, there were no differences between the models in infarct size (P = 0.53), left ventricular (LV) ejection fraction (P = 0.19), LV end systolic volume (P = 0.22), LV end diastolic volume (P = 0.84), and cardiac output (P = 0.89). Histologically, cardiac scars did not differ and the collagen content, collagen type I (I), collagen type III (III), and the I/III ratio were similar in both groups. Inflammation was assessed using specific anti-CD3 and anti-CD25 antibodies. There was similar activation of inflammation throughout the heart after coil embolization (P = 0.78); while, there were more activated lymphocytes in the infarcted myocardium in the surgical occlusion model (P = 0.02). Less myocardial vascularization in the infarction areas compared with the border and remote zones only in coil embolization animals was observed (P = 0.004 and P = 0.014, respectively).

Conclusions

Our results support that surgical occlusion and coil embolization MI models generate similar infarct size, cardiac function impairment, and myocardial fibrosis; although, inflammation and myocardial vascularization levels were closer to those found in humans when coil embolization was performed.