Recent advances in primary percutaneous intervention for acute myocardial infarction

The Inflammatory Cytokine IL-3 Hampers Cardioprotection Mediated by Endothelial Cell-Derived Extracellular Vesicles Possibly via Their Protein Cargo

The biological relevance of extracellular vesicles (EV) released in an ischemia/reperfusion setting is still unclear. We hypothesized that the inflammatory microenvironment prevents cardioprotection mediated by endothelial cell (EC)-derived extracellular vesicles. The effects of naïve EC-derived EV (eEV) or eEV released in response to interleukin-3 (IL-3) (eEV-IL-3) were evaluated in cardiomyoblasts (H9c2) and rat hearts. In transwell assay, eEV protected the H9c2 exposed to hypoxia/reoxygenation (H/R) more efficiently than eEV-IL-3. Conversely, only eEV directly protected H9c2 cells to H/R-induced damage. Consistent with this latter observation, eEV, but not eEV-IL-3, exerted beneficial effects in the whole heart. Protein profiles of eEV and eEV-IL-3, established using label-free mass spectrometry, demonstrated that IL-3 drives changes in eEV-IL-3 protein cargo. Gene ontology analysis revealed that both eEV and eEV-IL-3 were equipped with full cardioprotective machinery, including the Nitric Oxide Signaling in the Cardiovascular System. eEV-IL-3 were also enriched in the endothelial-nitric oxide-synthase (eNOS)-antagonist caveolin-1 and proteins related to the inflammatory response. In vitro and ex vivo experiments demonstrated that a functional Mitogen-Activated Protein Kinase Kinase (MEK1/2)/eNOS/guanylyl-cyclase (GC) pathway is required for eEV-mediated cardioprotection. Consistently, eEV were found enriched in MEK1/2 and able to induce the expression of B-cell-lymphoma-2 (Bcl-2) and the phosphorylation of eNOS in vitro. We conclude that an inflammatory microenvironment containing IL-3 changes the eEV cargo and impairs eEV cardioprotective action.

Protection from Reperfusion Injury with Intracoronary N-Acetylcysteine in Patients with STEMI Undergoing Primary Percutaneous Coronary Intervention in a Cardiac Tertiary Center

BACKGROUND

Evidence suggests that oxidative stress plays a principal role in myocardial damage following ischemia/reperfusion events. Recent studies have shown that the antioxidant properties of N-acetylcysteine (NAC) may have cardioprotective effects in high doses, but-to the best of our knowledge-few studies have assessed this.

OBJECTIVES

Our objective was to investigate the impact of high-dose NAC on ischemia/reperfusion injury.

METHODS

We conducted a randomized double-blind placebo-controlled trial in which 100 consecutive patients with ST-elevation myocardial infarction undergoing percutaneous coronary intervention (PCI) were randomly assigned to the case group (high-dose NAC 100 mg/kg bolus followed by intracoronary NAC 480 mg during PCI then intravenous NAC 10 mg/kg for 12 h) or the control group (5% dextrose). We measured differences in peak creatine kinase-myocardial band (CK-MB) concentration, highly sensitive troponin T (hs-TnT), thrombolysis in myocardial infarction (TIMI) flow, myocardial blush grade (MBG), and corrected thrombolysis in myocardial infarction frame count (cTFC).

RESULTS

The peak CK-MB level was comparable between the two groups (P = 0.327), but patients receiving high-dose NAC demonstrated a significantly larger reduction in hs-TnT (P = 0.02). In total, 94% of the NAC group achieved TIMI flow grade 3 versus 80% of the control group (P = 0.03). No significant differences were observed between the two groups in terms of changes in the cTFC and MBG.

CONCLUSIONS

In this study, NAC improved myocardial reperfusion markers and coronary blood flow, as revealed by differences in peak hs-TnT and TIMI flow grade 3 levels, respectively. Further studies with large samples are warranted to elucidate the role of NAC in this population. ClinicalTrials.gov identifier: NCT01741207, and the Iranian Registry of Clinical Trials (IRCT; http://irct.ir ) registration number: IRCT201301048698N8.

Randomised, double-blind, placebo-controlled study investigating the effects of inorganic nitrate on vascular function, platelet reactivity and restenosis in stable angina: protocol of the NITRATE-OCT study

INTRODUCTION

The mainstay treatment for reducing the symptoms of angina and long-term risk of heart attacks in patients with heart disease is stent implantation in the diseased coronary artery. While this procedure has revolutionised treatment, the incidence of secondary events remains a concern. These repeat events are thought to be due, in part, to continued enhanced platelet reactivity, endothelial dysfunction and ultimately restenosis of the stented artery. In this study, we will investigate whether a once a day inorganic nitrate administration might favourably modulate platelet reactivity and endothelial function leading to a decrease in restenosis.

METHODS AND DESIGN

NITRATE-OCT is a double-blind, randomised, single-centre, placebo-controlled phase II trial that will enrol 246 patients with stable angina due to have elective percutaneous coronary intervention procedure with stent implantation. Patients will be randomised to receive 6 months of a once a day dose of either nitrate-rich beetroot juice or nitrate-deplete beetroot juice (placebo) starting up to 1 week before their procedure. The primary outcome is reduction of in-stent late loss assessed by quantitative coronary angiography and optical coherence tomography at 6 months. The study is powered to detect a 0.22±0.55 mm reduction in late loss in the treatment group compared with the placebo group. Secondary end points include change from baseline assessment of endothelial function measured using flow-mediated dilation at 6 months, target vessel revascularisation (TVR), restenosis rate (diameter>50%) and in-segment late loss at 6 months, markers of inflammation and platelet reactivity and major adverse cardiac events (ie, myocardial infarction, death, cerebrovascular accident, TVR) at 12 and 24 months.

ETHICS AND DISSEMINATION

The study was approved by the Local Ethics Committee (15/LO/0555). Trial results will be published according to the CONSORT statement and will be presented at conferences and reported in peer-reviewed journals.

TRIAL REGISTRATION NUMBERS

NCT02529189 and ISRCTN17373946, Pre-results.

The combined effect of subcutaneous granulocyte- colony stimulating factor and myocardial contrast echocardiography with intravenous infusion of sulfur hexafluoride on post-infarction left ventricular function, the RIGENERA 2.0 trial: study protocol for a randomized controlled trial

BACKGROUND

Several clinical trials and recent meta-analyses have demonstrated that administration of recombinant human granulocyte-colony stimulating factor (G-CSF) is safe and, only in patients with large acute myocardial infarction (AMI), is associated with an improvement in left ventricular ejection fraction. Moreover, the mobilization and engraftment of the bone marrow-derived cells may differ significantly among patients, interfering with the restoration of left ventricular function after treatment. Therefore, the clinical potential application of the G-CSF has not yet been fully elucidated.

METHODS/DESIGN

The RIGENERA 2.0 trial is a multicenter, phase II, placebo-controlled, randomized, open-label, with blinded evaluation of endpoints (PROBE) trial in which 120 patients with an acute ST-elevation myocardial infarction (STEMI) undergoing successful revascularization but with residual myocardial dysfunction will be enrolled. In cases where there is a left ventricular ejection fraction (LVEF) ≤ 45% the patient will be electronically randomized (1:1 ratio) to receive either subcutaneous recombinant human G-CSF (group 1) or placebo (group 2) both added on top of optimal standard of care. Both groups will undergo myocardial contrast echocardiography with intravenous infusion of sulfur hexafluoride (MCE) whilst undergoing the echocardiogram. The primary efficacy endpoint is the evaluation of the LVEF at 6 months after AMI assessed by cardiac magnetic resonance. Secondary efficacy endpoints are the evaluation of LVEF at 6 months after AMI assessed by echocardiography, left ventricular end-diastolic volume (LVEDV) and left ventricular end-systolic volume (LVESV) assessed by cardiac magnetic resonance and echocardiography at 6 months, together with the incidence of major adverse clinical events (MACE) defined as death, myocardial infarction, sustained cardiac arrhythmias, cardiogenic shock, stroke and re-hospitalization due to heart failure at 1 year.

DISCUSSION

The RIGENERA 2.0 trial will test whether G-CSF administration and MCE, through the enhancement of the bone marrow-derived cells homing in the myocardium, determines an improvement in regional and global contractile function, myocardial perfusion and infarct extension in patients with large AMI. The results of the present study are expected to envision routine clinical use of this safe, affordable and reproducible approach in patients with successful revascularization after AMI.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02502747 (29 June 2015); EudraCT: 2015-002189-21 (10 July 2015).

The safety and efficacy of intracoronary nitrite infusion during acute myocardial infarction (NITRITE-AMI): study protocol of a randomised controlled trial

INTRODUCTION

Acute myocardial infarction (AMI) is a major cause of death and disability in the UK and worldwide. Presently, timely and effective reperfusion with primary percutaneous coronary intervention (PPCI) remains the most effective treatment strategy for limiting infarct size, preserving left ventricular ejection fraction (LVEF) and improving clinical outcomes. However, the process of reperfusion can itself induce cardiomyocyte death, known as myocardial reperfusion injury, for which there is currently no effective therapy. Extensive preclinical evidence exists to suggest that sodium nitrite (as a source of endogenous nitric oxide) is an effective therapeutic strategy for preventing myocardial reperfusion injury. The purpose of NITRITE-AMI is to test whether sodium nitrite reduces reperfusion injury and subsequent infarct size in patients undergoing PPCI for MI.

METHODS AND DESIGN

NITRITE-AMI is a double-blind, randomised, single-centre, placebo-controlled trial to determine whether intracoronary nitrite injection reduces infarct size in patients with myocardial infarction undergoing primary angioplasty. The study will enrol 80 patients presenting with ST-elevation myocardial infarction. Patients will be randomised to receive either a bolus of intracoronary sodium nitrite or placebo (sodium chloride) at the time of PPCI. The primary outcome is infarct size assessed by creatine kinase area under the curve (AUC) over 48 h. Secondary endpoints include troponin T AUC and infarct size, LV dimensions and myocardial salvage index assessed by cardiac MR (CMR), markers of platelet reactivity and inflammation, the safety and tolerability of intracoronary nitrite, and 1 year major adverse cardiac events.

ETHICS AND DISSEMINATION

The study is approved by the local ethics committee (NRES Committee London West London: 11/LO/1500) and by the Medicines and Healthcare Products Regulatory Agency (MHRA) (EudraCT nr. 2010-022460-12). The results of the trial will be published according to the CONSORT statement and will be presented at conferences and reported in peer-reviewed journals.

TRIAL REGISTRATION

United Kingdom Clinical Research Network (Study ID 12117), http://clinicaltrials.gov (NCT01584453) and Current Controlled Trials (ISRCTN:38736987).