A single dose of erythropoietin in ST-elevation myocardial infarction

Role of Erythropoiesis-Stimulating Agents in Cardiovascular Protection in CKD Patients: Reappraisal of Their Impact and Mechanisms

Erythropoiesis-stimulating agents (ESAs) have markedly reduced the need for blood transfusion for renal anemia and are included in standard therapies for patients with chronic kidney disease (CKD). Various protective effects of ESAs on the cardiovascular system have been discovered through basic research, and the effects have received much attention because the rates of cardiovascular events and mortality are high in CKD patients. However, randomized clinical trials did not provide strong evidence that ESAs exert cardioprotection in humans, including CKD patients. It is difficult to assess the cardioprotective effects of ESAs in CKD patients through the clinical data that has been reported to date because the relationship between hemoglobin level rather than ESA dose and cardiovascular event rates was examined in most studies. Interestingly, recent studies using a rat model of CKD showed that the infarct size-limiting effect of an ESA was lost when its dose was increased to a level that normalized blood hemoglobin levels, suggesting that the optimal dose of an ESA for myocardial protection is less than the dose required to normalize hemoglobin levels. Furthermore, animal models of traditional coronary risk factors or comorbidities were resistant to the cardioprotective effects of ESAs because of interruptions in signal-mediated mechanisms downstream of erythropoietin receptors. In this review, we briefly discuss basic and clinical data on the impact of anemia on coronary and systemic circulation, the effects of CKD on the cardiovascular system, and the multiple pharmacological actions of ESAs to examine whether the ESAs that are prescribed for renal anemia exert any cardioprotection in patients with CKD.

Microvascular Leakage as Therapeutic Target for Ischemia and Reperfusion Injury

Reperfusion injury is a very common complication of various indicated therapies such as the re-opening of vessels in the myocardium or brain as well as reflow in hemodynamic shutdown (cardiac arrest, severe trauma, aortic cross-clamping). The treatment and prevention of reperfusion injury has therefore been a topic of immense interest in terms of mechanistic understanding, the exploration of interventions in animal models and in the clinical setting in major prospective studies. While a wealth of encouraging results has been obtained in the lab, the translation into clinical success has met with mixed outcomes at best. Considering the still very high medical need, progress continues to be urgently needed. Multi-target approaches rationally linking interference with pathophysiological pathways as well as a renewed focus on aspects of microvascular dysfunction, especially on the role of microvascular leakage, are likely to provide new insights.

Growth factor for therapeutic angiogenesis in ischemic heart disease: A meta-analysis of randomized controlled trials

Aim: This study was designed to systematically evaluate the effects of growth factor (GF) for therapeutic angiogenesis on ischemic heart disease (IHD) by pooling the results of randomized controlled trials (RCTs). Methods and Results: PubMed, EMBASE, and CENTRAL databases were searched from inception to October 2022. RCTs, investigating the effects of GF therapy on IHD, were included. The risk bias of included study was assessed according to Cochrane tool. Weighted mean difference (WMD), calculated with fixed effect model or random effect model, was used to evaluate the effects of GF therapy on left ventricular ejection fraction (LVEF) and Canadian Cardiovascular Society (CCS) angina class. Relative risk (RR) was used to evaluate the effects of GF therapy on all-cause mortality, major adverse cardiovascular events (MACE) and revascularization. Meta-analysis, meta-regression analysis and publication bias analysis were performed by RevMan 5.3 or Stata 15.1 software. Twenty-nine studies involving 2899 IHD patients (1,577 patients in GF group and 1,322 patients in control group) were included. Compared with the control group, GF therapy did not reduce all-cause mortality (RR: 0.82; 95% CI: 0.54-1.24; p = 0.341), MACE [(RR: 0.83; 95% CI: 0.61-1.12; p = 0.227), revascularization (RR: 1.27, 95% CI: 0.82-1.96, p = 0.290) and CCS angina class (WMD: -0.08, 95% CI: -0.36 to 0.20, p = 0.560). However, GF therapy could increase LVEF during short-term follow-up (<1 year). Conclusion: GF for therapeutic angiogenesis was beneficial for increasing LVEF during short-term follow-up (<1 year), however, the therapy was not efficacious in decreasing all-cause mortality, MACE and revascularization.

Protective or Inhibitory Effect of Pharmacological Therapy on Cardiac Ischemic Preconditioning: A Literature Review

Ischemic preconditioning (IP) is an innate phenomenon, triggered by brief, non-lethal cycles of ischemia/reperfusion applied to a tissue or organ that confers tolerance to a subsequent more prolonged ischemic event. Once started, it can reduce the severity of myocardial ischemia associated with some clinical situations, such as percutaneous coronary intervention (PCI) and intermittent aortic clamping during coronary artery bypass graft surgery (CABG). Although the mechanisms underlying IP have not been completely elucidated, several studies have shown that this phenomenon involves the participation of cell triggers, intracellular signaling pathways, and end-effectors. Understanding this mechanism enables the development of preconditioning mimetic agents. It is known that a range of medications that activate the signaling cascades at different cellular levels can interfere with both the stimulation and the blockade of IP. Investigations of signaling pathways underlying ischemic conditioning have identified a number of therapeutic targets for pharmacological manipulation. This review aims to present and discuss the effects of several medications on myocardial IP.

The role of anemia on admission in acute coronary syndrome - An umbrella review of systematic reviews and meta-analyses

INTRODUCTION

The role of erythrocytes in the acute coronary syndrome (ACS) is complex. The aim of this review in terms of PICO (P: patients; I: intervention; C: comparison; O: outcome) was to summarize systematic reviews in patients (P) with acute coronary syndrome, evaluating the effects of (I) 1) iron deficiency, 2) administration of an erythropoiesis-stimulating agent (ESA), 3) anemia on admission, 4) red blood cell transfusion, 5) a restrictive transfusion strategy in comparison (C) to 1) no iron deficiency, 2) no ESA 3) no anemia on admission, 4) no red blood cell transfusion, 5) a liberal transfusion strategy on mortality (O).

METHODS

We used AMSTAR2 to assess the methodological quality of systematic reviews and grade the available research. The primary endpoint was all-cause mortality.

RESULTS

Using the data from 2,787,005 patients, the following conditions were associated with worse outcome in patients with ACS: anemia on admission (RR 2.08 95%CI 1.70-2.55) and transfusion (1.93 95%CI 1.12-3.34) of red blood cells. A liberal transfusion (RR 0.86 95%CI 0.70-1-05), administration of ESA (RR 0.55 95%CI 0.22-1.33) and iron deficiency (OR 1.24 95%CI 0.12-13.13) were not associated with altered all-cause mortality.

CONCLUSION

Patients suffering from ACS and anemia on admission are at particular risk for adverse outcome. There is evidence of associations between adverse outcomes and receiving red blood cell transfusions.

Myocardial protection by heparin-based coacervate of FGF10

Heart disease is still the leading killer all around the world, and its incidence is expected to increase over the next decade. Previous reports have already shown the role of fibroblast growth factor10 (FGF10) in alleviating heart diseases. However, FGF10 has not been used to treat heart diseases because the free protein has short half-life and low bioactivity. Here, an injectable coacervate was designed to protect growth factor from degradation during delivery and the effects of the FGF10 coacervate were studied using a mice acute myocardial infarction (MI) model. As shown in our echocardiographic results, a single injection of FGF10 coacervate effectively inhibited preserved cardiac contractibility and ventricular dilation when compared with free FGF10 and the saline treatment 6 weeks after MI. It is revealed in histological results that the MI induced myocardial inflammation and fibrosis was reduced after FGF10 coacervate treatment. Furthermore, FGF10 coacervate treatment could improve arterioles and capillaries stabilization through increasing the proliferation of endothelial and mural cells. However, with the same dosage, no statistically significant difference was shown between free FGF10, heparin+FGF10 and saline treatment, especially in long term. On another hand, FGF10 coacervate also increased the expression of cardiac-associated the mRNA (cTnT, Cx43 and α-SMA), angiogenic factors (Ang-1 and VEGFA) and decreased the level of inflammatory factor (tumor necrosis factor-α). The downstream signaling of the FGF10 was also investigated, with the western blot results showing that FGF10 coacervate activated the p-FGFR, PI3K/Akt and ERK1/2 pathways to a more proper level than free FGF10 or heparin+FGF10. In general, it is revealed in this research that one-time injection of FGF10 coacervate sufficiently attenuated MI induced injury when compared with an equal dose of free FGF10 or heparin+FGF10 injection.

Therapies to prevent post-infarction remodelling: From repair to regeneration

Myocardial infarction is the first cause of worldwide mortality, with an increasing incidence also reported in developing countries. Over the past decades, preclinical research and clinical trials continually tested the efficacy of cellular and acellular-based treatments. However, none of them resulted in a drug or device currently used in combination with either percutaneous coronary intervention or coronary artery bypass graft. Inflammatory, proliferation and remodelling phases follow the ischaemic event in the myocardial tissue. Only recently, single-cell sequencing analyses provided insights into the specific cell populations which determine the final fibrotic deposition in the affected region. In this review, ischaemia, inflammation, fibrosis, angiogenesis, cellular stress and fundamental cellular and molecular components are evaluated as therapeutic targets. Given the emerging evidence of biomaterial-based systems, the increasing use of injectable hydrogels/scaffolds and epicardial patches is reported both as acellular and cellularised/functionalised treatments. Since several variables influence the outcome of any experimented treatment, we return to the pathological basis with an unbiased view towards any specific process or cellular component. Thus, by evaluating the benefits and limitations of the approaches based on these targets, the reader can weigh the rationale of each of the strategies that reached the clinical trials stage. As recent studies focused on the relevance of the extracellular matrix in modulating ischaemic remodelling and enhancing myocardial regeneration, we aim to portray current trends in the field with this review. Finally, approaches towards feasible translational studies that are as yet unexplored are also suggested.

Helix B Surface Peptide Protects Cardiomyocytes From Hypoxia/Reoxygenation-induced Autophagy Through the PI3K/Akt Pathway

BACKGROUND

Helix B surface peptide (HBSP) is a newly discovered tissue-protective erythropoietin derivative that provides benefits after myocardial ischemia/reperfusion. This study explores the cardioprotective effects of HBSP in myocardial cells in response to hypoxia/reoxygenation injury and its potential mechanism.

METHODS

In this study, rat ventricular (H9c2) cell cultures were established and pretreated with HBSP. H9c2 cardiomyocytes were randomly assigned to the control, H/R, H/R + LY294002 (a PI3K inhibitor), HBSP + H/R, and HBSP + H/R + LY294002 groups. The pretreated cardiomyocytes underwent H/R, and the cardiomyocytes were monitored for viability through a CCK-8 assay, whereas flow cytometry was used to test cell apoptosis. Orgotein Superoxide Dismutase (SOD) and lactate dehydrogenase (LDH) expression were monitored by SOD and LDH kits, respectively. The expression of LC3 autophagosomes was determined by immunocytochemistry. The expression of LC3II/LC3I, p-Mammalian Target of Rapamycin (mTOR) mTOR, mTOR, Beclin 1, p-PI3K, PI3K p-Akt, and Akt was determined by Western blotting.

RESULTS

HBSP increased cell viability and reduced SOD and LDH production, and it also reduced H/R-induced cell apoptosis. Moreover, the expression of the autophagy-related proteins (LC3II/LC3I) was inhibited by HBSP, whereas the expression of p-PI3K, p-Akt, and p-mTOR was enhanced. However, the PI3K inhibitor (LY294002) notably abolished these effects in H9c2 cells.

CONCLUSIONS

HBSP inhibits excessive autophagy and apoptosis induced by H/R by activating the PI3K/Akt pathway. HBSP may potentially be a therapeutic intervention for myocardial ischemia/reperfusion injury.

Pharmacologic Prevention of Myocardial Ischemia-Reperfusion Injury in Patients With Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention

ABSTRACT

Establishing efficient perfusion into the myocardium is the main purpose in patients with acute coronary syndrome, but the process of reperfusion is not without risk and can damage the myocardium paradoxically. Unfortunately, there is no effective treatment for reperfusion injury, and efforts to find an efficient preventive approach are still ongoing. In the past 3 decades, there have been many successful animal studies on how to prevent reperfusion injury; nonetheless, translation to the clinical setting has almost always proven disappointing. In this article, we review clinical studies on the prevention of reperfusion injury in patients with acute coronary syndrome undergoing primary percutaneous coronary intervention in a pharmacologic-based approach. We categorize all the agents that are evaluated for the prevention of myocardial reperfusion injury based on their mechanisms of action into 5 groups: drugs that can reduce oxidative stress, drugs that can affect cellular metabolism, rheological agents that target microvascular obstruction, anti-inflammatory agents, and agents with mixed mechanisms of action. Then, review all the clinical studies of these agents in the setting of primary percutaneous coronary intervention. Finally, we will discuss the possible reasons for the failure in translation of studies into practice and propose potential solutions to overcome this problem.

EPO and EPO-Receptor System as Potential Actionable Mechanism for the Protection of Brain and Heart in Refractory Epilepsy and SUDEP

The most important activity of erythropoietin (EPO) is the regulation of erythrocyte production by activation of the erythropoietin receptor (EPO-R), which triggers the activation of anti-apoptotic and proliferative responses of erythroid progenitor cells. Additionally, to erythropoietic EPO activity, an antiapoptotic effect has been described in a wide spectrum of tissues. EPO low levels are found in the central nervous system (CNS), while EPO-R is expressed in most CNS cell types. In spite of EPO-R high levels expressed during the hypoxicischemic brain, insufficient production of endogenous cerebral EPO could be the cause of determined circuit alterations that lead to the loss of specific neuronal populations. In the heart, high EPO-R expression in cardiac progenitor cells appears to contribute to myocardial regeneration under EPO stimulation. Several lines of evidence have linked EPO to an antiapoptotic role in CNS and in heart tissue. In this review, an antiapoptotic role of EPO/EPO-R system in both brain and heart under hypoxic conditions, such as epilepsy and sudden death (SUDEP) has been resumed. Additionally, their protective effects could be a new field of research and a novel therapeutic strategy for the early treatment of these conditions and avoid SUDEP.

Acute myocardial infarction and cardiogenic shock: Should we unload the ventricle before percutaneous coronary intervention?

Despite early reperfusion and coordinated systems of care, cardiogenic shock (CS) remains the number one cause of morbidity and in-hospital mortality following acute myocardial infarction (AMI). CS is a complex clinical syndrome that begins with hemodynamic instability and can progress to multi-organ failure and profound hemo-metabolic compromise. To improve outcomes, a clear understanding of the treatment objectives in CS and developing time-sensitive management strategies aimed at stabilizing hemodynamics and restoring myocardial perfusion are critical. Left ventricular (LV) load has been identified as an independent predictor of heart failure and mortality following AMI. Decades of preclinical and clinical research have identified several effective LV unloading strategies. Recent initiatives from single and multi-center registries and more recently the Door to Unload (DTU)-STEMI pilot study have provided valuable insight to developing a standardized treatment approach to AMI, based on early invasive hemodynamics and tailored circulatory support to unload the LV. To follow is a review of the pathophysiology and prevalence of shock, limitations of current therapies, and the pre-clinical and translational basis for incorporating LV unloading into contemporary AMI and shock care.

Efficacy of IntraCoronary Erythropoietin Delivery BEfore Reperfusion-Gauging Infarct Size in Patients with Acute ST-segment Elevation Myocardial Infarction (ICEBERG)

Previous clinical studies have shown inconsistent results regarding the effect of erythropoietin in ST-segment elevation myocardial infarction (STEMI). This study investigated whether directed intracoronary infusion of darbepoetin-α into ischemic myocardium before reperfusion would reduce infarct size or post-infarct remodeling in STEMI patients.Eighty STEMI patients received one of the following treatments simultaneously with the first balloon inflation: intracoronary darbepoetin-α 300 μg (n = 40) or saline (n = 40), administered via the over-the-wire balloon system. The primary endpoint was infarct size estimated by serial cardiac enzyme levels after procedure. The secondary endpoints were (1) infarct size and proportion of salvaged myocardium measured with cardiac magnetic resonance (CMR) at baseline; (2) post-infarct remodeling (PIR), defined as an increase in left ventricular end-diastolic volume more than 20% at 4 months compared to the baseline on CMR; and (3) composite cardiovascular endpoints assessed at 4 months.The peak CK-MB [median 270.0 (interquartile range 139.8-356.3) versus 231.5 (131.0-408.5) ng/mL, P = 0.55] and troponin-I [128.5 (63.5-227.8) versus 109.0 (43.8-220.0) ng/mL, P = 0.52) ] did not differ between the darbepoetin-α and control group. Fifty-seven patients completed the baseline and 4-month follow-up CMR. There were no differences in infarct size [30.6 (18.1-49.8) versus 31.5 (22.5-47.3) cm³, P = 0.91), proportion of salvaged myocardium [26.7% (15.9-42.6%) versus 35.8% (22.4-48.8%), P = 0.12) or PIR (8.0% versus 6.7%, P = 0.62) between the two groups. Composite cardiovascular outcomes did not differ between the two groups.In conclusion, administration of intracoronary darbepoetin-α before reperfusion did not reduce infarct size or post-infarct remodeling in STEMI patients.

Effect of Erythropoietin Administration on Myocardial Viability and Coronary Microvascular Dysfunction in Anterior Acute Myocardial Infarction: Randomized Controlled Trial in the Japanese Population

Introduction

Cardioprotective effects of erythropoietin (EPO) on infarcted myocardium in acute myocardial infarction (AMI) patients have been inconclusive. This study aimed to assess the effect of EPO administration on coronary microvascular dysfunction (CMD) and myocardial viability in anterior AMI. We also evaluated the serial changes in CMD and cardiac remodeling in these patients.

Methods

Patients with a successful percutaneous coronary intervention (PCI) for the first anterior AMI were randomly assigned to two groups (EPO and control groups), and given single-dose intravenous administration of recombinant human EPO (12,000 IU) or saline after PCI. Delayed-enhanced cardiac magnetic resonance imaging was performed at 1 week after AMI to assess the average of transmural extent of infarction and infarct size. Coronary flow velocity reserve (CFVR) of the left anterior descending coronary artery was measured by Doppler echocardiography at 1 week, 1 month, and 8 months after AMI. All patients underwent clinical follow-up for the assessment of cardiac remodeling.

Results

Sixty-one patients (EPO 32, control 29) were eligible for analysis. EPO group (2.4 ± 1.2) had a tendency of smaller transmural extent of infarction than that of control group (2.9 ± 1.1; p = 0.063). CFVR-8 months improved significantly in EPO group (2.9 ± 0.6) compared to control group (2.6 ± 0.5; p = 0.04). Left atrial (LA) volume − 8 months was significantly lower in EPO group (47 ± 11) than those of control group (65 ± 20; p = 0.004).

Conclusions

A single medium dose of EPO could have a favorable effect on CMD and LA remodeling in the chronic phase of anterior AMI.

Trial Registration

The institutional ethics committee of Wakayama Medical University, identifier, 1125.

Electronic supplementary material

The online version of this article (10.1007/s40119-018-0122-1) contains supplementary material, which is available to authorized users.

The pathophysiology of acute myocardial infarction and strategies of protection beyond reperfusion: a continual challenge

The incidence of ST segment elevation myocardial infarction (STEMI) has decreased over the last two decades in developed countries, but mortality from STEMI despite widespread access to reperfusion therapy is still substantial as is the development of heart failure, particularly among an expanding older population. In developing countries, the incidence of STEMI is increasing and interventional reperfusion is often not available. We here review the pathophysiology of acute myocardial infarction and reperfusion, notably the temporal and spatial evolution of ischaemic and reperfusion injury, the different modes of cell death, and the resulting coronary microvascular dysfunction. We then go on to briefly characterize the cardioprotective phenomena of ischaemic preconditioning, ischaemic postconditioning, and remote ischaemic conditioning and their underlying signal transduction pathways. We discuss in detail the attempts to translate conditioning strategies and drug therapy into the clinical setting. Most attempts have failed so far to reduce infarct size and improve clinical outcomes in STEMI patients, and we discuss potential reasons for such failure. Currently, it appears that remote ischaemic conditioning and a few drugs (atrial natriuretic peptide, exenatide, metoprolol, and esmolol) reduce infarct size, but studies with clinical outcome as primary endpoint are still underway.

Helix B Surface Peptide Protects Cardiomyocytes Against Hypoxia/Reoxygenation-induced Apoptosis Through Mitochondrial Pathways

BACKGROUND

Helix B surface peptide (HBSP), a newly developed tissue-protective erythropoietin derivative, has beneficial effects on myocardial ischemia. This study aimed to investigate the cardio-protective effects of HBSP against hypoxia/reoxygenation (H/R) injury and its possible mechanism.

METHODS

A rat-derived cardiomyocyte cell line (H9C2 cells) were established and pretreated with HBSP. The pretreated primary cultures were subjected to H/R and monitored for cell viability using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. Intracellular reactive oxygen species (ROS) levels, apoptosis, and mitochondrial membrane potential (ΔΨm) were detected by flow cytometry. The expression of cytochrome C and Bcl-2 family proteins, as well as the activities of caspases 3 and 9 were determined by Western blot analysis and a colorimetric method, respectively.

RESULTS

HBSP reduced apoptotic cells in cardiomyocytes subjected to H/R. In HBSP-treated cardiomyocytes, the H/R-induced mitochondrial ROS production, ΔΨm collapse, and cytochrome C release from mitochondria to the cytosol significantly decreased. Moreover, HBSP inhibited the activation of caspases 9 and 3, as well as the alteration of Bcl-2 family proteins, which were induced by H/R.

CONCLUSIONS

These results indicated that HBSP has protective effects against H/R-induced apoptosis by regulating the mitochondrial pathway. This mechanism involves inhibiting mitochondrial ROS generation, inhibiting caspase-3 activity, reducing ΔΨm collapse, reducing cytochrome release, and balancing anti and proapoptotic Bcl-2 family proteins.

Harms of off-label erythropoiesis-stimulating agents for critically ill people

BACKGROUND

Anaemia is a common problem experienced by critically-ill people. Treatment with erythropoiesis-stimulating agents (ESAs) has been used as a pharmacologic strategy when the blunted response of endogenous erythropoietin has been reported in critically-ill people. The use of ESAs becomes more important where adverse clinical outcomes of transfusing blood products is a limitation. However, this indication for ESAs is not licensed by regulatory authorities and is called off-label use. Recent studies concern the harm of ESAs in a critical care setting.

OBJECTIVES

To focus on harms in assessing the effects of erythropoiesis-stimulating agents (ESAs), alone or in combination, compared with placebo, no treatment or a different active treatment regimen when administered off-label to critically-ill people.

SEARCH METHODS

We conducted a systematic search of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, PsycINFO via OvidSP, CINAHL, all evidence-based medicine (EBM) reviews including IPA and SCI-Expanded, Conference Proceedings Citation Index- Science, BIOSIS Previews and TOXLINE up to February 2017. We also searched trials registries, checked reference lists of relevant studies and tracked their citations by using SciVerse Scopus.

SELECTION CRITERIA

We considered randomized controlled trials (RCTs) and controlled observational studies, which compared scheduled systemic administration of ESAs versus other effective interventions, placebo or no treatment in critically-ill people.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened and evaluated the eligibility of retrieved records, extracted data and assessed the risks of bias and quality of the included studies. We resolved differences in opinion by consensus or by involving a third review author. We assessed the evidence using GRADE and created a 'Summary of findings' table. We used fixed-effect or random-effects models, depending on the heterogeneity between studies. We fitted three-level hierarchical Bayesian models to calculate overall treatment effect estimates.

MAIN RESULTS

Of the 27,865 records identified, 39 clinical trials and 14 observational studies, including a total of 945,240 participants, were eligible for inclusion. Five studies are awaiting classification. Overall, we found 114 adverse events in 33 studies (30 RCTs and three observational studies), and mortality was reported in 41 studies (32 RCTs and nine observational studies). Most studies were at low to moderate risk of bias for harms outcomes. However, overall harm assessment and reporting were of moderate to low quality in the RCTs, and of low quality in the observational studies. We downgraded the GRADE quality of evidence for venous thromboembolism and mortality to very low and low, respectively, because of risk of bias, high inconsistency, imprecision and limitations of study design.It is unclear whether there is an increase in the risk of any adverse events (Bayesian risk ratio (RR) 1.05, 95% confidence interval (CI) 0.93 to 1.21; 3099 participants; 9 studies; low-quality evidence) or venous thromboembolism (Bayesian RR 1.04, 95% CI 0.70 to 1.41; 18,917 participants; 18 studies; very low-quality evidence).There was a decreased risk of mortality with off-label use of ESAs in critically-ill people (Bayesian RR 0.76, 95% CI 0.61 to 0.92; 930,470 participants; 34 studies; low-quality evidence).

AUTHORS' CONCLUSIONS

Low quality of evidence suggests that off-label use of ESAs may reduce mortality in a critical care setting. There was a lack of high-quality evidence about the harm of ESAs in critically-ill people. The information for biosimilar ESAs is less conclusive. Most studies neither evaluated ESAs' harm as a primary outcome nor predefined adverse events. Any further studies of ESA should address the quality of evaluating, recording and reporting of adverse events.

The Erythropoietin System Protects the Heart Upon Injury by Cardiac Progenitor Cell Activation

Erythropoietin (EPO) is a growth hormone, widely known for its role in erythropoiesis. The broad expression of erythropoietin receptor (EPOR) in adult organs suggested that EPO may also affect other cells besides late erythroid progenitors. In the embryonic heart, EPOR is expressed in all cells including the immature proliferating cardiomyocytes. In contrast to the embryonic heart in adulthood, EPOR expression is decreased and mainly detected in immature proliferating cells (i.e., resident cardiac progenitor cells) rather than in terminally differentiated cells (i.e., cardiomyocytes). Since cardiac progenitor cells are considered a regenerative cell source upon cardiac injury, the protective action of the EPO system was tested by creating an erythroid-rescued EPOR knockout mouse model. Although these mice appear to have less immature proliferating myocytes during embryogenesis, they reach adulthood without apparent morphological defects. However, upon ischemia reperfusion, these animals show a greater infarct size, suggesting that the EPO/EPOR protects the heart upon injury. Indeed preclinical studies showed that EPO administration postinfarction improves cardiac function via neoangiogenesis, antiapoptotic mechanisms, and/or CPC activation. Despite the promising preclinical data, large cohort clinical studies in humans failed to show a significant amelioration in cardiac function upon systemic injection of EPO in patients with myocardial infarctions. The discrepancy between preclinical and clinical trials may be due to differences between the doses, the way of delivery, the homogeneity of the cohorts, and last but not least the species differences. These data pinpoint the importance of carrying out preclinical studies in human models of disease as engineered human cardiac tissue that will provide a better understanding of the expression pattern of EPOR and the role of its ligand in human cardiac cells. Such studies may be able to bridge the gap between preclinical rodent data and human clinical trials and thus lead to the design of more successful clinical studies.

Fibroblast Growth Factor-1 Released from a Heparin Coacervate Improves Cardiac Function in a Mouse Myocardial Infarction Model

Emerging evidence supports the beneficial effect of fibroblast growth factor-1 (FGF1) on heart diseases, but its application has been hindered by the short half-life and limited bioactivity of the free protein. We designed an injectable coacervate to facilitate robust growth factor delivery, which would both protect and increase the bioactivity of growth factors. In this study, a model for acute myocardial infarction was established in mice, and the cardioprotective effect of the FGF1 coacervate was investigated. Echocardiographic results showed that the FGF1 coacervate inhibited ventricular dilation and preserved cardiac contractibility more than the free FGF1 and the saline control within the 6-week duration of the experiments. Histological examination revealed that the FGF1 coacervate reduced inflammation and fibrosis post-MI, significantly increased the proliferation of endothelial and mural cells, and resulted in stable arterioles and capillaries. Furthermore, the FGF1 coacervate improved the proliferation of cardiac stem cells 6 weeks post-MI. However, free FGF1, dosed identically, did not show significant difference from saline treatment. Thus, one injection of FGF1 coacervate was sufficient to attenuate the injury caused by MI, and the results were significantly better than those obtained from an equal dose of free FGF1.

Signaling Pathways in Cardiac Myocyte Apoptosis

Cardiovascular diseases, the number 1 cause of death worldwide, are frequently associated with apoptotic death of cardiac myocytes. Since cardiomyocyte apoptosis is a highly regulated process, pharmacological intervention of apoptosis pathways may represent a promising therapeutic strategy for a number of cardiovascular diseases and disorders including myocardial infarction, ischemia/reperfusion injury, chemotherapy cardiotoxicity, and end-stage heart failure. Despite rapid growth of our knowledge in apoptosis signaling pathways, a clinically applicable treatment targeting this cellular process is currently unavailable. To help identify potential innovative directions for future research, it is necessary to have a full understanding of the apoptotic pathways currently known to be functional in cardiac myocytes. Here, we summarize recent progress in the regulation of cardiomyocyte apoptosis by multiple signaling molecules and pathways, with a focus on the involvement of these pathways in the pathogenesis of heart disease. In addition, we provide an update regarding bench to bedside translation of this knowledge and discuss unanswered questions that need further investigation.

Strategy to Prime the Host and Cells to Augment Therapeutic Efficacy of Progenitor Cells for Patients with Myocardial Infarction

Cell therapy in myocardial infarction (MI) is an innovative strategy that is regarded as a rescue therapy to repair the damaged myocardium and to promote neovascularization for the ischemic border zone. Among several stem cell sources for this purpose, autologous progenitors from bone marrow or peripheral blood would be the most feasible and safest cell-source. Despite the theoretical benefit of cell therapy, this method is not widely adopted in the actual clinical practice due to its low therapeutic efficacy. Various methods have been used to augment the efficacy of cell therapy in MI, such as using different source of progenitors, genetic manipulation of cells, or priming of the cells or hosts (patients) with agents. Among these methods, the strategy to augment the therapeutic efficacy of the autologous peripheral blood mononuclear cells (PBMCs) by priming agents may be the most feasible and the safest method that can be applied directly to the clinic. In this review, we will discuss the current status and future directions of priming PBMCs or patients, as for cell therapy of MI.

Baseline Hemoglobin Levels Associated with One-Year Mortality in ST-Segment Elevation Myocardial Infarction Patients

BACKGROUND

The association between hemoglobin (Hb) levels and mortality in patients with ST-segment elevation myocardial infarction (STEMI) remains controversial. The purpose of this study was to examine the mortality among STEMI patients with anemia or erythrocytosis, and further establish the relationship between mortality and the increment of Hb level.

METHODS

Between 2006 and 2012, 951 consecutive patients with STEMI undergoing primary percutaneous coronary intervention in a medical center in Northern Taiwan were enrolled in our study, including 535 patients with normal Hb level, 148 with anemia (male Hb ≤ 13 g/dl, female ≤ 12) and 268 with erythrocytosis (male Hb ≥ 16, female ≥ 15).

RESULTS

Patients in the anemia group were the oldest, and had higher morbidity than the normal Hb group, followed by the erythrocytosis group. In regression analyses, neither anemia nor erythrocytosis was associated with 30-day and 1-year mortality. Each 1-g/dl increment of Hb level was not associated with 30-day mortality both in patients with anemia or erythrocytosis. However, it was associated with a decreased risk of 1-year mortality in anemic patients [hazard ratio (HR): 0.756, 95% confidence interval (CI): 0.608-0.938, p = 0.011] and an increased risk of 1-year mortality in those with erythrocytosis (HR: 2.086, 95%CI: 1.106-3.937, p = 0.023). In multivariate analysis, each 1-g/dl increment of Hb level was associated with 1-year mortality both in anemic patients and those with erythrocytosis (HR: 0.788, 95%CI: 0.621-0.999, p = 0.049; HR: 2.302, 95%CI: 1.051-5.04, p = 0.037).

CONCLUSIONS

Higher hemoglobin levels in STEMI patients with anemia were associated with decreased risks of 1-year mortality, whereas higher hemoglobin levels in those with erythrocytosis were associated with increased risks of one-year mortality.

Mitochondrial Membrane Permeability Inhibitors in Acute Myocardial Infarction: Still Awaiting Translation

Despite therapeutic advances, acute myocardial infarction (AMI) remains a leading cause of morbidity and mortality worldwide. One potential limitation of the current treatment paradigm is the lack of effective therapies to optimize reperfusion after ischemia and prevent reperfusion-mediated injury. Experimental studies indicate that this process accounts for up to 50% of the final infarct size, lending it importance as a potential target for cardioprotection. However, multiple therapeutic approaches have shown potential in pre-clinical and early phase trials but a paucity of clear clinical benefit when expanded to larger studies. Here we explore this history of trials and errors of the studies of cyclosporine A and other mitochondrial membrane permeability inhibitors, agents that appeared to have a promising pre-clinical record yet provided disappointing results in phase III clinical trials.

Catheter-based Intramyocardial Injection of FGF1 or NRG1-loaded MPs Improves Cardiac Function in a Preclinical Model of Ischemia-Reperfusion

Cardiovascular protein therapeutics such as neuregulin (NRG1) and acidic-fibroblast growth factor (FGF1) requires new formulation strategies that allow for sustained bioavailability of the drug in the infarcted myocardium. However, there is no FDA-approved injectable protein delivery platform due to translational concerns about biomaterial administration through cardiac catheters. We therefore sought to evaluate the efficacy of percutaneous intramyocardial injection of poly(lactic-co-glycolic acid) microparticles (MPs) loaded with NRG1 and FGF1 using the NOGA MYOSTAR injection catheter in a porcine model of ischemia-reperfusion. NRG1- and FGF1-loaded MPs were prepared using a multiple emulsion solvent-evaporation technique. Infarcted pigs were treated one week after ischemia-reperfusion with MPs containing NRG1, FGF1 or non-loaded MPs delivered via clinically-translatable percutaneous transendocardial-injection. Three months post-treatment, echocardiography indicated a significant improvement in systolic and diastolic cardiac function. Moreover, improvement in bipolar voltage and decrease in transmural infarct progression was demonstrated by electromechanical NOGA-mapping. Functional benefit was associated with an increase in myocardial vascularization and remodeling. These findings in a large animal model of ischemia-reperfusion demonstrate the feasibility and efficacy of using MPs as a delivery system for growth factors and provide strong evidence to move forward with clinical studies using therapeutic proteins combined with catheter-compatible biomaterials.

Improving myocardial injury, infarct size, and myocardial salvage in the era of primary PCI for STEMI

ST-segment elevation myocardial infarction (STEMI) is a major cause of mortality and disability worldwide. Reperfusion therapy by thrombolysis or primary percutaneous coronary intervention (PPCI) improves survival and quality of life in patients with STEMI. Despite the proven efficacy of timely reperfusion, mortality from STEMI remains high, particularly among patients with suboptimal reperfusion. Reperfusion injury following opening of occluded coronary arteries mitigates the efficacy of PPCI by further accentuating ischemic damage and increasing infarct size (IS). On the basis of experimental studies, it is assumed that nearly 50% of the final IS is because of the reperfusion injury. IS is a marker of ischemic damage and adequacy of reperfusion that is strongly related to mortality in reperfused patients with STEMI. Many therapeutic strategies including pharmacological and conditioning agents have been proven effective in reducing reperfusion injury and IS in preclinical research. Mechanistically, these agents act either by inhibiting reperfusion injury cascades or by activating cellular prosurvival pathways. Although most of these agents/strategies are at the experimental stage, some of them have been tested clinically in patients with STEMI. This review provides an update on key pharmacological agents and postconditioning used in the setting of PPCI to reduce reperfusion injury and IS. Despite intensive research, no strategy or intervention has been shown to prevent reperfusion injury or enhance myocardial salvage in a consistent manner in a clinical setting. A number of novel therapeutic strategies to reduce reperfusion injury in the setting of PPCI in patients with STEMI are currently under investigation. They will lead to a better understanding of reperfusion injury and to more efficient strategies for its prevention.

Erythropoietin Reduces Post-PCI Arrhythmias in Patients With ST-elevation Myocardial Infarction

BACKGROUND

Arrhythmia is the foremost cause of sudden death after myocardial infarction (MI). Animal models have recently shown that erythropoietin (EPO) can reduce the incidence of arrhythmia after MI.

METHODS

We investigated the effects of administrating 33,000 IU EPO on the occurrence of post-MI arrhythmia in 40 patients with ST-elevation MI who were randomly assigned in either EPO or placebo groups. Arrhythmias were blindly documented using full 12-lead configuration during 24 hours after percutaneous coronary intervention (PCI) by a cardiologist. Afterward, CK-MB, hematologic, and hemodynamic data were examined within 2 weeks after MI.

RESULTS

A comparison made between the 2 groups showed significant differences in the incidence of arrhythmias (20% in EPO group and 35% in placebo group, P = 0.043). However, no significant differences in type of arrhythmias were observed between the groups. There was no significant difference between levels of CK-MB in the 2 groups during 24 hours (P = 0.186). Hematologic and hemodynamic data showed no significant changes 2 weeks after PCI.

CONCLUSION

High-dose administration of EPO in patients with ST-elevation MI who have been treated by primary PCI and standard antiplatelet therapy reduces the occurrence of arrhythmias. For clinical interpretation of the results, further well-designed trials are required.

Helix B Surface Peptide Protects against Acute Myocardial Ischemia-Reperfusion Injury via the RISK and SAFE Pathways in a Mouse Model

OBJECTIVE

This study explores the effects of helix B surface peptide (HBSP) on myocardial infarct size (IS), cardiac function, cardiomyocyte apoptosis and oxidative stress damage in mouse hearts subjected to myocardial ischemia-reperfusion injury (MIRI) and also the mechanisms underlying the effects.

METHOD

Male adult mice were subjected to 45 min of ischemia followed by 2 h of reperfusion; 5 min before the reperfusion, they were treated with HBSP or vehicle. MIRI-induced IS, cardiomyocyte apoptosis and cardiac functional impairment were determined and compared. Western blot analysis was then conducted to elucidate the mechanism of HBSP after treatment.

RESULTS

HBSP administration before reperfusion significantly reduced the myocardial IS, decreased cardiomyocyte apoptosis, reduced the activities of superoxide dismutase and malondialdehyde and partially preserved heart function. As demonstrated by the Western blot analysis, HBSP after treatment upregulated Akt/GSK-3β/ERK and STAT-3 phosphorylation; these inhibitors, in turn, weakened the beneficial effects of HBSP.

CONCLUSION

HBSP plays a protective role in MIRI in mice by inhibiting cardiomyocyte apoptosis, reducing the MIRI-induced IS, oxidative stress and improving the heart function after MIRI. The mechanism underlying these effects of HBSP is related to the activation of the RISK (reperfusion injury salvage kinase, Akt/GSK-3β/ERK) and SAFE (STAT-3) pathways.

Erythropoietin responsive cardiomyogenic cells contribute to heart repair post myocardial infarction

The role of erythropoietin (Epo) in myocardial repair after infarction remains inconclusive. We observed high Epo receptor (EPOR) expression in cardiac progenitor cells (CPCs). Therefore, we aimed to characterize these cells and elucidate their contribution to myocardial regeneration on Epo stimulation. High EPOR expression was detected during murine embryonic heart development followed by a marked decrease until adulthood. EPOR-positive cells in the adult heart were identified in a CPC-enriched cell population and showed coexpression of stem, mesenchymal, endothelial, and cardiomyogenic cell markers. We focused on the population coexpressing early (TBX5, NKX2.5) and definitive (myosin heavy chain [MHC], cardiac Troponin T [cTNT]) cardiomyocyte markers. Epo increased their proliferation and thus were designated as Epo-responsive MHC expressing cells (EMCs). In vitro, EMCs proliferated and partially differentiated toward cardiomyocyte-like cells. Repetitive Epo administration in mice with myocardial infarction (cumulative dose 4 IU/g) resulted in an increase in cardiac EMCs and cTNT-positive cells in the infarcted area. This was further accompanied by a significant preservation of cardiac function when compared with control mice. Our study characterized an EPO-responsive MHC-expressing cell population in the adult heart. Repetitive, moderate-dose Epo treatment enhanced the proliferation of EMCs resulting in preservation of post-ischemic cardiac function.

Coronary microvascular obstruction in acute myocardial infarction

The success of a primary percutaneous intervention (PCI) in the setting of ST elevation myocardial infarction depends on the functional and structural integrity of coronary microcirculation. Coronary microvascular dysfunction and obstruction (CMVO) occurs in up to half of patients submitted to apparently successful primary PCI and is associated to a much worse outcome. The current review summarizes the complex mechanisms responsible for CMVO, including pre-existing coronary microvascular dysfunction, and highlights the current limitations in the assessment of microvascular function. More importantly, at the light of the substantial failure of trials hitherto published on the treatment of CMVO, this review proposes a novel integrated therapeutic approach, which should overcome the limitations of previous studies.

Contemporary perspective on endogenous myocardial regeneration

Considering the complex nature of the adult heart, it is no wonder that innate regenerative processes, while maintaining adequate cardiac function, fall short in myocardial jeopardy. In spite of these enchaining limitations, cardiac rejuvenation occurs as well as restricted regeneration. In this review, the background as well as potential mechanisms of endogenous myocardial regeneration are summarized. We present and analyze the available evidence in three subsequent steps. First, we examine the experimental research data that provide insights into the mechanisms and origins of the replicating cardiac myocytes, including cell populations referred to as cardiac progenitor cells (i.e., c-kit+ cells). Second, we describe the role of clinical settings such as acute or chronic myocardial ischemia, as initiators of pathways of endogenous myocardial regeneration. Third, the hitherto conducted clinical studies that examined different approaches of initiating endogenous myocardial regeneration in failing human hearts are analyzed. In conclusion, we present the evidence in support of the notion that regaining cardiac function beyond cellular replacement of dysfunctional myocardium via initiation of innate regenerative pathways could create a new perspective and a paradigm change in heart failure therapeutics. Reinitiating cardiac morphogenesis by reintroducing developmental pathways in the adult failing heart might provide a feasible way of tissue regeneration. Based on our hypothesis “embryonic recall”, we present first supporting evidence on regenerative impulses in the myocardium, as induced by developmental processes.

Functional EpoR pathway utilization is not detected in primary tumor cells isolated from human breast, non-small cell lung, colorectal, and ovarian tumor tissues

Several clinical trials in oncology have reported increased mortality or disease progression associated with erythropoiesis-stimulating agents. One hypothesis proposes that erythropoiesis-stimulating agents directly stimulate tumor proliferation and/or survival through cell-surface receptors. To test this hypothesis and examine if human tumors utilize the erythropoietin receptor pathway, the response of tumor cells to human recombinant erythropoietin was investigated in disaggregated tumor cells obtained from 186 patients with colorectal, breast, lung, ovarian, head and neck, and other tumors. A cocktail of well characterized tumor growth factors (EGF, HGF, and IGF-1) were analyzed in parallel as a positive control to determine whether freshly-isolated tumor cells were able to respond to growth factor activation ex vivo. Exposing tumor cells to the growth factor cocktail resulted in stimulation of survival and proliferation pathways as measured by an increase in phosphorylation of the downstream signaling proteins AKT and ERK. In contrast, no activation by human recombinant erythropoietin was observed in isolated tumor cells. Though tumor samples exhibited a broad range of cell-surface expression of EGFR, c-Met, and IGF-1R, no cell-surface erythropoietin receptor was detected in tumor cells from the 186 tumors examined (by flow cytometry or Western blot). Erythropoiesis-stimulating agents did not act directly upon isolated tumor cells to stimulate pathways known to promote proliferation or survival of human tumor cells isolated from primary and metastatic tumor tissues.

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.

Remote conditioning the heart overview: translatability and mechanism

Conditioning the heart to resist predictable and unpredictable ischaemia-reperfusion (IR) injury is one of the fastest growing areas of bench to bedside research within cardiology. Basic science has provided important insights into signalling pathways and protective mechanisms in the heart, and a growing number of clinical studies have, with important exceptions, shown the potential applicability and beneficial effect of various mechanical conditioning strategies achieved by intermittent short-lasting-induced ischaemia of the heart itself or a remote tissue. Remote ischaemic conditioning (RIC) in particular has been utilized in a number of clinical settings with promising results. However, while many novel 'downstream' mechanisms of RIC have been discovered, translation to pharmacological conditioning has not yet been convincingly demonstrated in clinical studies. One explanation for this apparent failure may be that most pharmacological approaches mimic a single instrument in a complex orchestra activated by mechanical conditioning. Recent studies, however, provide important insights into upstream events occurring in RIC, which may allow for development of drugs activating more complex systems of biological organ protection. With this review, we will systematically examine the first generation of pharmacological cardioprotection studies and then provide a summary of the recent discoveries in basic science that could illuminate the path towards more advanced approaches in the next generation of pharmacological agents that may work by reproducing the diverse effects of RIC, thereby providing protection against IR injury.

High-dose erythropoietin for tissue protection

BACKGROUND

The discovery of potential anti-apoptotic and cytoprotective effects of recombinant human erythropoietin (rHuEPO) has led to clinical trials investigating the use of high-dose, short-term rHuEPO therapy for tissue protection in conditions such as stroke and myocardial infarction. Experimental studies have been favourable, but the clinical efficacy has yet to be validated.

MATERIALS AND METHODS

We have reviewed clinical studies regarding the use of high-dose, short-term rHuEPO therapy for tissue protection in humans with the purpose to detail the safety and efficacy of rHuEPO for this indication. A systematic literature search was performed using the PubMed/MEDLINE database for randomized, placebo-controlled clinical trials.

RESULTS

Twenty-six randomized controlled trials that enrolled 3176 patients were included. The majority of trials (20 trials including 2724 patients) reported no effect of rHuEPO therapy on measures of tissue protection. Five trials including 1025 patients reported safety concerns in the form of increased mortality or adverse event rates. No studies reported reduced mortality.

CONCLUSIONS

Evidence is sparse to support a tissue-protective benefit of rHuEPO in humans. Moreover, a number of studies indicate that short-term administration of high-dose rHuEPO is associated with an increased risk of mortality and serious adverse events. Further work is needed to elucidate the mechanisms of toxicity of rHuEPO in humans.

Safety and clinical outcome of erythropoiesis-stimulating agents in patients with ST-elevation myocardial infarction: a meta-analysis of individual patient data

BACKGROUND

Erythropoiesis-stimulating agents (ESAs) have been investigated in small studies in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). Erythropoiesis-stimulating agents did not show a clear effect on left ventricular function or clinical outcome, but some studies suggested an increased risk of thromboembolic events.

METHODS

A systematic literature search in MEDLINE was performed, until December 2012. We included randomized clinical trials investigating the effect of ESAs in STEMI patients undergoing primary PCI, with ≥30 days of follow-up. The primary end point was a composite of all-cause mortality, myocardial infarction, and stent thrombosis after PCI. Secondary end point was all-cause mortality.

RESULTS

Individual patient data were obtained from 10 of 11 trials, including 97.3% (1,242/1,277) of all patients randomized to control (n = 600) or to ESAs (n = 642). Baseline characteristics were well balanced between the treatment allocations. Mean follow-up time was 248 (±131) days. The primary end point occurred in 3.5% (20/577) in the control group and in 2.1% (13/610) in the ESA group (hazard ratio for ESAs, 0.63; 95% CI [0.31-1.27]; P = .20). Mortality occurred in 13 (2.3%) in the control group and 5 (0.8%) in the ESA group (hazard ratio for ESAs, 0.38; 95% CI [0.13-1.06]; P = .06).

CONCLUSIONS

Erythropoiesis-stimulating agent administration does not result in an increased risk of adverse cardiac events in STEMI patients undergoing primary PCI. Results of ongoing studies may provide further insight to the potential beneficial clinical effects of ESAs in STEMI patients.

The influence of Erythropoietin on platelet activation, thrombin generation and FVII/active FVII in patients with AMI

BACKGROUND

Erythropoietin (Epo) has been shown to improve myocardial function in models of experimental myocardial infarction, but has also been associated with a rise in thromboembolic events. Thus, the aim of this study was to investigate the influence of Epo on platelet activation and coagulation in patients with acute myocardial infarction (AMI).

METHODS

The study was designed as a substudy of the randomised, double-blind, placebo controlled REVIVAL-3 (REgeneration of VItal Myocardium in ST-Segment EleVation MyocardiAL Infarction by Erythropoietin) study that investigated the effects of recombinant human Epo in AMI. Serial venous blood samples were collected before and after study medication. Circulating prothrombin fragment F1 + 2, FVII, active FVII, beta thromboglobulin (TG) and P-Selectin were measured before and 60 hours after randomization by immunoassay (n = 94). In a randomly selected subgroup platelet aggregation was measured using whole blood aggregometry (Multiplate Analyzer, n = 45).

RESULTS

After 5 days an increase in FVII was observed after Epo as compared to placebo (P = 0.02), yet active FVII and prothrombin fragment F1 + 2 remained unchanged. Moreover, no statistically significant differences in circulating TG or P-selectin were observed between the groups. As an expected response to peri-interventional therapy with clopidogrel and aspirin, platelet aggregation after stimulation with ADP, TRAP, ASPI or collagen decreased 12 hours and 2 days after PCI. However, no difference between the Epo and the placebo group was observed.

CONCLUSION

After treatment with Epo in patients with AMI a slight increase in circulating FVII after Epo was not associated with an increase in active FVII, prothrombin fragment F1 + 2, TG or P-selectin. Moreover, platelet aggregation was not altered after treatment with Epo as compared to placebo.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01761435.

Functional polymers of gene delivery for treatment of myocardial infarct

Ischemic heart disease is rapidly growing as the common cause of death in the world. It is a disease that occurs as a result of coronary artery stenosis and is caused by the lack of oxygen within cardiac muscles due to an imbalance between oxygen supply and demand. The conventional medical therapy is focused on the use of drug eluting stents, coronary-artery bypass graft surgery and anti-thrombosis. Gene therapy provides great opportunities for treatment of cardiovascular disease. In order for gene therapy to be successful, the development of proper gene delivery systems and hypoxia-regulated gene expression vectors is the most important factors. Several non-viral gene transfer methods have been developed to overcome the safety problems of viral transduction. Some of which include plasmids that regulate gene expression that is controlled by environment specific promoters in the transcriptional or the translational level. This review explores polymeric gene carriers that target the myocardium and hypoxia-inducible vectors, which regulate gene expression in response to hypoxia, and their application in animal myocardial infarction models.

Novel adjunctive treatments of myocardial infarction

Myocardial infarction is a major cause of death and disability worldwide and myocardial infarct size is a major determinant of prognosis. Early and successful restoration of myocardial reperfusion following an ischemic event is the most effective strategy to reduce final infarct size and improve clinical outcome, but reperfusion may induce further myocardial damage itself. Development of adjunctive therapies to limit myocardial reperfusion injury beyond opening of the coronary artery gains increasing attention. A vast number of experimental studies have shown cardioprotective effects of ischemic and pharmacological conditioning, but despite decades of research, the translation into clinical effects has been challenging. Recently published clinical studies, however, prompt optimism as novel techniques allow for improved clinical applicability. Cyclosporine A, the GLP-1 analogue exenatide and rapid cooling by endovascular infusion of cold saline all reduce infarct size and may confer clinical benefit for patients admitted with acute myocardial infarcts. Equally promising, three follow-up studies of the effect of remote ischemic conditioning (RIC) show clinical prognostic benefit in patients undergoing coronary surgery and percutaneous coronary intervention. The discovery that RIC can be performed noninvasively using a blood pressure cuff on the upper arm to induce brief episodes of limb ischemia and reperfusion has facilitated the translation of RIC into the clinical arena. This review focus on novel advances in adjunctive therapies in relation to acute and elective coronary procedures.

Erythropoietin in cardiac disease: effective or harmful?

Discovered as the primary regulator of erythropoiesis, erythropoietin (EPO) is involved in a broad variety of processes that play a major role in cardiovascular diseases. In particular, the antiapoptotic and pro-angiogenic properties of EPO have prompted a growing interest in the use of EPO for the treatment of myocardial infarction and heart failure. In a variety of myocardial ischemic injury animal models, EPO administration has been shown to acutely reduce infarct size, thereby preserving ventricular function. In addition, cardiac long-term effects of EPO, such as prevention of ventricular remodeling and heart failure, have been described. In recent years, several trials have tested the effects of recombinant human erythropoietin (rhEPO) administration in patients with myocardial infarction and chronic heart failure, in the attempt to translate the cardioprotection found in experimental models to human patients. In view of the generally controversial findings, in this updated review we provide an overview of the results of the most recent trials that investigated the role of erythropoiesis-stimulating agents (ESAs), including rhEPO and its analogue darbepoetin, in the treatment of acute myocardial infarction and heart failure. The problems related to safety and tolerability of ESA therapy are also discussed. Our analysis of the available literature demonstrates that the results of clinical studies in patients with cardiac disease are not uniform and the conclusions are contradictory. Further larger prospective studies are required to test clinical efficacy and safety of EPO.

Erythropoietin action in stress response, tissue maintenance and metabolism

Erythropoietin (EPO) regulation of red blood cell production and its induction at reduced oxygen tension provides for the important erythropoietic response to ischemic stress. The cloning and production of recombinant human EPO has led to its clinical use in patients with anemia for two and half decades and has facilitated studies of EPO action. Reports of animal and cell models of ischemic stress in vitro and injury suggest potential EPO benefit beyond red blood cell production including vascular endothelial response to increase nitric oxide production, which facilitates oxygen delivery to brain, heart and other non-hematopoietic tissues. This review discusses these and other reports of EPO action beyond red blood cell production, including EPO response affecting metabolism and obesity in animal models. Observations of EPO activity in cell and animal model systems, including mice with tissue specific deletion of EPO receptor (EpoR), suggest the potential for EPO response in metabolism and disease.

Serum corin is reduced and predicts adverse outcome in non-ST-elevation acute coronary syndrome

BACKGROUND AND OBJECTIVES

The aim of the current study was to describe the role of corin, an enzyme that cleaves pro-atrial natriuretic peptide and pro-brain natriuretic peptide into their active peptides, in patients with acute coronary syndrome (ACS).

METHODS

Serum corin level was studied in patients with non-ST-elevation ACS who underwent percutaneous coronary intervention (n=152) and in control volunteers (n=103).

RESULTS

The corin level was lower in acute coronary syndrome patients (798±288 pg/ml) than in the controls (1165±613 pg/ml, p<0.0001). Those acute coronary syndrome patients who developed major adverse cardiovascular events (MACE; 60.9%) within 3 years of discharge had lower corin levels than the patients who did not experience major adverse cardiovascular events (698.16±233.67 vs. 952.1±297.81 pg/ml, p<0.0001). Using a multiple logistic regression model, corin level was a significant predictor of post-ACS MACE: p=0.0004 for 50 pg/ml steps, AUC 0.791, while p<0.0001, and AUC 0.804 using corin and brain natriuretic peptide as predictors.

CONCLUSIONS

Patients with non-ST-elevation ACS have lower serum corin levels than controls. Corin levels are lower in ACS patients who later experience MACE and thus might be predictor for MACE. This new putative biomarker may be useful, either alone or in combination with other biomarkers, for cardiovascular risk stratification assessment and outcome prediction in ACS patients.

Long term effects of epoetin alfa in patients with ST- elevation myocardial infarction

PURPOSE

The HEBE III trial showed that epoetin alfa administration in patients with a first ST-elevation myocardial infarction (STEMI) did not improve left ventricular function at 6 weeks after primary percutaneous coronary intervention (PCI). The long term effects of erythropoiesis- stimulating agents on cardiovascular morbidity and mortality are unknown, therefore we evaluated clinical events at 1 year after PCI.

METHODS

A total of 529 patients with a first STEMI and successful primary PCI were randomized to standard optimal medical treatment (N = 266) or an additional bolus of 60,000 IU epoetin alfa administered intravenously (N = 263) within 3 h after PCI. Analyses were performed by intention to treat.

RESULTS

At 1 year after STEMI, 485 patients had complete follow-up. The rate of the composite end point of all-cause mortality, re-infarction, target vessel revascularization, stroke and/or heart failure was 6.4 % (N = 15) in the epoetin alfa group and 9.6 % (N = 24) in the control group (p = 0.18). Thromboembolic events were present in 1.3 % (N = 3) of patients in the epoetin alfa group and 2.4 % (N = 6) in the control group. There was no evidence of benefit from epoetin alfa administration in subgroups of patients.

CONCLUSIONS

Administration of a single bolus of epoetin alfa in patients with STEMI does not result in a reduction of cardiovascular events at 1 year after primary PCI. There was a comparable incidence of thromboembolic complications in both treatment groups, suggesting that epoetin alfa administration is safe at long term.