Cardioprotective role of remote ischemic periconditioning in primary percutaneous coronary intervention: enhancement by opioid action

The New Orientation of Postoperative Analgesia: Remote Ischemic Preconditioning

Purpose of Review

Postoperative analgesia is currently a significant topic in anesthesiology. Currently, the predominant approach for achieving multimodal analgesia involves the utilization of pharmacotherapy and regional anesthesia procedures. The primary objectives of this approach are to mitigate postoperative pain, enhance patient satisfaction, and diminish overall opioid usage. Nevertheless, there is a scarcity of research on the use of remote ischemia preconditioning aimed at mitigating postoperative pain.

Recent Findings

Transient stoppage of blood flow to an organ has been found to elicit remote ischemia preconditioning (RIPC), which serves as a potent intrinsic mechanism for protecting numerous organs. In addition to its established role in protecting against reperfusion injury, RIPC has recently been identified as having potential benefits in the context of postoperative analgesia.

Summary

In addition to traditional perioperative analgesia, RIPC provides perioperative analgesia and organ protection.

Health position paper and redox perspectives on reactive oxygen species as signals and targets of cardioprotection

The present review summarizes the beneficial and detrimental roles of reactive oxygen species in myocardial ischemia/reperfusion injury and cardioprotection. In the first part, the continued need for cardioprotection beyond that by rapid reperfusion of acute myocardial infarction is emphasized. Then, pathomechanisms of myocardial ischemia/reperfusion to the myocardium and the coronary circulation and the different modes of cell death in myocardial infarction are characterized. Different mechanical and pharmacological interventions to protect the ischemic/reperfused myocardium in elective percutaneous coronary interventions and coronary artery bypass grafting, in acute myocardial infarction and in cardiotoxicity from cancer therapy are detailed. The second part keeps the focus on ROS providing a comprehensive overview of molecular and cellular mechanisms involved in ischemia/reperfusion injury. Starting from mitochondria as the main sources and targets of ROS in ischemic/reperfused myocardium, a complex network of cellular and extracellular processes is discussed, including relationships with Ca2+ homeostasis, thiol group redox balance, hydrogen sulfide modulation, cross-talk with NAPDH oxidases, exosomes, cytokines and growth factors. While mechanistic insights are needed to improve our current therapeutic approaches, advancements in knowledge of ROS-mediated processes indicate that detrimental facets of oxidative stress are opposed by ROS requirement for physiological and protective reactions. This inevitable contrast is likely to underlie unsuccessful clinical trials and limits the development of novel cardioprotective interventions simply based upon ROS removal.

Regulation of the JAK/STAT signaling pathway: The promising targets for cardiovascular disease

Individuals have known that Janus kinase (JAK) signal transducer and activator of transcription (STAT) signaling pathway was involved in the growth of the cell, cell differentiation courses advancement, immune cellular survival, as well as hematopoietic system advancement. Researches in the animal models have already uncovered a JAK/STAT regulatory function in myocardial ischemia-reperfusion injury (MIRI), acute myocardial infarction (MI), hypertension, myocarditis, heart failure, angiogenesis and fibrosis. Evidences originating in these studies indicate a therapeutic JAK/STAT function in cardiovascular diseases (CVDs). In this retrospection, various JAK/STAT functions in the normal and ill hearts were described. Moreover, the latest figures about JAK/STAT were summarized under the background of CVDs. Finally, we discussed the clinical transformation prospects and technical limitations of JAK/STAT as the potential therapeutic targets for CVDs. This collection of evidences has essential meanings for the clinical application of JAK/STAT as medicinal agents for CVDs. In this retrospection, various JAK/STAT functions in the normal and ill hearts were described. Moreover, the latest figures about JAK/STAT were summarized under the background of CVDs. Finally, we discussed the clinical transformation prospects and toxicity of JAK/STAT inhibitors as potential therapeutic targets for CVDs. This collection of evidences has essential meanings for the clinical application of JAK/STAT as medicinal agents for CVDs.

Remote ischemic conditioning in necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a devastating intestinal inflammatory disorder, most prevalent in premature infants, and associated with a high mortality rate that has remained unchanged in the past two decades. NEC is characterized by inflammation, ischemia, and impaired microcirculation in the intestine. Preclinical studies by our group have led to the discovery of remote ischemic conditioning (RIC) as a promising non-invasive intervention in protecting the intestine against ischemia-induced damage during early-stage NEC. RIC involves the administration of brief reversible cycles of ischemia and reperfusion in a limb (similar to taking standard blood pressure measurement) which activate endogenous protective signaling pathways that are conveyed to distant organs such as the intestine. RIC targets the intestinal microcirculation and by improving blood flow to the intestine, reduces the intestinal damage of experimental NEC and prolongs survival. A recent Phase I safety study by our group demonstrated that RIC was safe in preterm infants with NEC. A phase II feasibility randomized controlled trial involving 12 centers in 6 countries is currently underway, to investigate the feasibility of RIC as a treatment for early-stage NEC in preterm neonates. This review provides a brief background on RIC as a therapeutic strategy and summarizes the progression of RIC as a treatment for NEC from preclinical investigation to clinical evaluation.

Spontaneous Reperfusion in Patients with Transient ST-Elevation Myocardial Infarction-Prevalence, Importance and Approaches to Management

Patients with transient ST-elevation myocardial infarction (STEMI) or spontaneous resolution (SpR) of the ST-segment elevation on electrocardiogram could potentially represent a unique group of patients posing a therapeutic management dilemma. In this review, we discuss the potential mechanisms underlying SpR, its relation to clinical outcomes and the proposed management options for patients with transient STEMI with a focus on immediate versus early percutaneous coronary intervention. We performed a structured literature search of PubMed and Cochrane Library databases from inception to December 2020. Studies focused on SpR in patients with acute coronary syndrome were selected. Available data suggest that deferral of angiography and revascularization within 24-48 h in these patients is reasonable and associated with similar or perhaps better outcomes than immediate angiography. Further randomized trials are needed to elucidate the best pharmacological and invasive strategies for this cohort.

The protective effect of remote ischemic conditioning is lost in patients with hypercholesterolemia

Remote ischemic conditioning (RIC), brief repetitive cycles of ischemia and reperfusion in remote tissues, is known to induce robust protection against myocardial ischemia-reperfusion (I/R) injury in preclinical studies. However, translation of the beneficial effects to the clinical setting has been challenging. A possibility is that comorbidities, including hypercholesterolemia, interfere with the protective mechanisms of RIC. The aim of this study was to test if hypercholesterolemia attenuates the efficacy of RIC in patients with hypercholesterolemia. Patients with familial hypercholesterolemia (FH) with high (≥5.5 mmol/L) low-density lipoprotein cholesterol (LDL-C), FH with low (≤2.5 mmol/L) and healthy control subjects (n = 12 in each group) were included. Flow-mediated vasodilatation (FMD) of the brachial artery was evaluated, before and after a 20-min period of forearm ischemia and 20 min reperfusion (I/R) as a measure of endothelial function. Study subjects were randomized to a RIC protocol consisting of four cycles of 5 min of leg ischemia or sham using a crossover design. Forearm I/R induced significant reduction in FMD in all three groups during the sham procedure. RIC protected from endothelial dysfunction induced by forearm ischemia-reperfusion in healthy controls [FMD baseline 2.8 ± 2.3 vs. FMD after I/R + RIC 4.5 ± 4.0%; means (SD)] and in patients with FH with low LDL-C (4.5 ± 3.5 vs. 4.4 ± 4.2%). By contrast, RIC fails to protect against I/R-induced endothelial dysfunction in patients with FH and high LDL-C (3.9 ± 3.0 vs. 1.1 ± 1.5%; P < 0.01). These findings provide the first evidence in humans that the protective effect of RIC is lost in patients with elevated cholesterol.NEW & NOTEWORTHY We investigated the impact of hypercholesterolemia on the protective effect of RIC on ischemia-reperfusion injury in a well-characterized patient population with isolated hypercholesterolemia. The results show that the protective effect of RIC is absent in patients with hypercholesterolemia but is apparent in patients with hypercholesterolemic following treatment with lipid-lowering drugs. The results are of importance for the understanding of how comorbidities affect the therapeutic potential of RIC.

Can Clinical and Functional Outcomes Be Improved with an Intelligent "Internet Plus"-Based Full Disease Cycle Remote Ischemic Conditioning Program in Acute ST-elevation Myocardial Infarction Patients Undergoing Percutaneous Coronary Intervention? Rationale and Design of the i-RIC Trial

BACKGROUND

Acute ST-elevation myocardial infarction (STEMI) is associated with a high incidence of complications as well as a considerable hospitalization rate and economic burden. Preliminary evidence suggests that remote ischemic conditioning (RIC) is a promising non-invasive intervention that may effectively and safely reduce myocardial infarct size, subsequent cardiac events and complications, and mortality. However, RIC's cardio-protective effect remains under debate, especially for single timepoint RIC programs. Adequately powered large-scale randomized controlled trials investigating clinical outcomes are thus needed to clarify the role of full disease cycle RIC programs.

METHODS

The intelligent "Internet Plus"-based full disease cycle remote ischemic conditioning (i-RIC) trial is a pragmatic, multicenter, randomized controlled, parallel group, clinical trial. The term, intelligent "Internet Plus"-based full disease cycle, refers to smart devices aided automatic and real-time monitoring of remote ischemic pre-, per- or post-conditioning intervention for patients with STEMI undergoing percutaneous coronary intervention (PCI). Based on this perspective, 4700 STEMI patients from five hospitals in China will be randomized to a control and an intervention group. The control group will receive PCI and usual care, including pharmacotherapy, before and after PCI. The intervention group will receive pre-, per-, and post-operative RIC combined with long-term i-RIC over a one-month period in addition. A smartphone application, an automated cuff inflation/deflation device and "Internet Plus"-based administration will be used in the long-term phase. The primary outcome is the combined cardiac death or hospitalization for heart failure rate. Secondary outcomes include clinical and functional outcomes: major adverse cardiac and cerebrovascular events rate, all-cause mortality, myocardial reinfarction rate, readmission rate for heart failure and ischemic stroke rate, unplanned revascularization rate, plasma concentration of myocardial infarction-related key biomarkers, infarct size, cardiac function, cardiopulmonary endurance, health-related quality of life, total hospital length of stay, total medical cost, and compliance with treatment regime.

DISCUSSION

The i-RIC trial is designed to test the hypothesis that clinical and functional outcomes can be improved with the i-RIC program in STEMI patients undergoing PCI. The concept of RIC is expected to be enhanced with this intelligent "Internet Plus"-based program focusing on the full disease cycle. If the i-RIC program results in superior improvement in primary and secondary outcomes, it will offer an innovative treatment option for STEMI patients and form the basis of future recommendations.

CLINICAL TRIAL REGISTRATION

Chinese Clinical Trial Registry ( http://www.chictr.org.cn ): ChiCTR2000031550, 04 April 2020.

New targets of morphine postconditioning protection of the myocardium in ischemia/reperfusion injury: Involvement of HSP90/Akt and C5a/NF-κB

Background

Activation of the complement component 5a (C5a) and nuclear factor κB (NF-κB) signaling is an important feature of myocardial ischemia/reperfusion (I/R) injury and recent studies show that morphine postconditioning (MP) attenuates the myocardial injury. However, the mediating cardioprotective mechanisms remain unclear. The present study explores the role and interaction of heat shock protein 90 (HSP90), Akt, C5a, and NF-κB in MP-induced cardioprotection.

Methods

Male Sprague Dawley rats (n = 160) were randomized into eight groups (n = 20 per group). Rats in the sham group underwent thoracotomy, passing the ligature through the heart but without tying it (150 min), and the other seven groups were subjected to 30 min of anterior descending coronary artery occlusion followed by 2 h of reperfusion and the following treatments: I/R (30 min of ischemia and followed by 2 h of reperfusion); ischemic postconditioning (IPostC, 30 s of ischemia altered with 30 s of reperfusion, repeated for three cycles, and followed by reperfusion for 2 h); MP (0.3 mg/kg morphine administration 10 min before reperfusion); MP combined with the HSP90 inhibitor geldanamycin (GA, 1 mg/kg); MP combined with the Akt inhibitor GSK-690693 (GSK, 20 mg/kg); and MP combined with the C5a inhibitor PMX205 (PMX, 1 mg/kg/day, administration via drinking water for 28 days) and MP combined with the NF-κB inhibitor EVP4593 (QNZ, 1 mg/kg). All inhibitors were administered 10 min before morphine and followed by 2 h reperfusion.

Results

MP significantly reduced the I/R-induced infarct size, the apoptosis, and the release of cardiac troponin I, lactate dehydrogenase (LDH), and creatine kinase-MB. These beneficial effects were accompanied by increased expression of HSP90 and p-Akt, and decreased expression of C5a, NF-κB, tumor necrosis factor α, interleukin-1β, and intercellular cell adhesion molecule 1. However, HSP90 inhibitor GA or Akt inhibitor GSK increased the expression of C5a and NF-κB and prevented MP-induced cardioprotection. Furthermore, GA inhibited the MP-induced upregulation of p-Akt, while GSK did not affect HSP90, indicating that p-Akt acts downstream of HSP90 in MP-induced cardioprotection. In addition, C5a inhibitor PMX enhanced the MP-induced downregulation of NF-κB, while NF-κB inhibitor QNZ had no effect on C5a, indicating that the C5a/NF-κB signaling pathway is involved in MP-induced cardioprotection.

Conclusion

HSP90 is critical for MP-mediated cardioprotection possibly by promoting the phosphorylation of Akt and inhibiting the activation of C5a and NF-κB signaling and the subsequent myocardial inflammation, ultimately attenuating the infarct size and cardiomyocyte apoptosis.

Remote but not Distant: a Review on Experimental Models and Clinical Trials in Remote Ischemic Conditioning as Potential Therapy in Ischemic Stroke

Stroke is one of the main causes of neurological disability worldwide and the second cause of death in people over 65 years old, resulting in great economic and social burden. Ischemic stroke accounts for 85% of total cases, and the approved therapies are based on re-establishment of blood flow, and do not directly target brain parenchyma. Thus, novel therapies are urgently needed. In this review, limb remote ischemic conditioning (RIC) is revised and discussed as a potential therapy against ischemic stroke. The review targets both (i) fundamental research based on experimental models and (ii) clinical research based on clinical trials and human interventional studies with healthy volunteers. Moreover, it also presents two approaches concerning RIC mechanisms in stroke: (i) description of the underlying cerebral cellular and molecular mechanisms triggered by limb RIC that promote neuroprotection against stroke induced damage and (ii) the identification of signaling factors involved in inter-organ communication following RIC procedure. Limb to brain remote signaling can occur via circulating biochemical factors, immune cells, and/or stimulation of autonomic nervous system. In this review, these three hypotheses are explored in both humans and experimental models. Finally, the challenges involved in translating experimentally generated scientific knowledge to a clinical setting are also discussed.

Effect of remote ischaemic conditioning on infarct size and remodelling in ST-segment elevation myocardial infarction patients: the CONDI-2/ERIC-PPCI CMR substudy

The effect of limb remote ischaemic conditioning (RIC) on myocardial infarct (MI) size and left ventricular ejection fraction (LVEF) was investigated in a pre-planned cardiovascular magnetic resonance (CMR) substudy of the CONDI-2/ERIC-PPCI trial. This single-blind multi-centre trial (7 sites in UK and Denmark) included 169 ST-segment elevation myocardial infarction (STEMI) patients who were already randomised to either control (n = 89) or limb RIC (n = 80) (4 × 5 min cycles of arm cuff inflations/deflations) prior to primary percutaneous coronary intervention. CMR was performed acutely and at 6 months. The primary endpoint was MI size on the 6 month CMR scan, expressed as median and interquartile range. In 110 patients with 6-month CMR data, limb RIC did not reduce MI size [RIC: 13.0 (5.1-17.1)% of LV mass; control: 11.1 (7.0-17.8)% of LV mass, P = 0.39], or LVEF, when compared to control. In 162 patients with acute CMR data, limb RIC had no effect on acute MI size, microvascular obstruction and LVEF when compared to control. In a subgroup of anterior STEMI patients, RIC was associated with lower incidence of microvascular obstruction and higher LVEF on the acute scan when compared with control, but this was not associated with an improvement in LVEF at 6 months. In summary, in this pre-planned CMR substudy of the CONDI-2/ERIC-PPCI trial, there was no evidence that limb RIC reduced MI size or improved LVEF at 6 months by CMR, findings which are consistent with the neutral effects of limb RIC on clinical outcomes reported in the main CONDI-2/ERIC-PPCI trial.

Combating Oxidative Stress and Inflammation in COVID-19 by Molecular Hydrogen Therapy: Mechanisms and Perspectives

COVID-19 is a widespread global pandemic with nearly 185 million confirmed cases and about four million deaths. It is caused by an infection with the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which primarily affects the alveolar type II pneumocytes. The infection induces pathological responses including increased inflammation, oxidative stress, and apoptosis. This situation results in impaired gas exchange, hypoxia, and other sequelae that lead to multisystem organ failure and death. As summarized in this article, many interventions and therapeutics have been proposed and investigated to combat the viral infection-induced inflammation and oxidative stress that contributes to the etiology and pathogenesis of COVID-19. However, these methods have not significantly improved treatment outcomes. This may partly be attributable to their inability at restoring redox and inflammatory homeostasis, for which molecular hydrogen (H2), an emerging novel medical gas, may complement. Herein, we systematically review the antioxidative, anti-inflammatory, and antiapoptotic mechanisms of H2. Its small molecular size and nonpolarity allow H2 to rapidly diffuse through cell membranes and penetrate cellular organelles. H2 has been demonstrated to suppress NF-κB inflammatory signaling and induce the Nrf2/Keap1 antioxidant pathway, as well as to improve mitochondrial function and enhance cellular bioenergetics. Many preclinical and clinical studies have demonstrated the beneficial effects of H2 in varying diseases, including COVID-19. However, the exact mechanisms, primary modes of action, and its true clinical effects remain to be delineated and verified. Accordingly, additional mechanistic and clinical research into this novel medical gas to combat COVID-19 complications is warranted.

Remote ischaemic conditioning in ST elevation myocardial infarction: a registry-based randomised trial

OBJECTIVES

Remote ischaemic conditioning (RIC) has been tested as a possible strategy for mitigating reperfusion injury in ST elevation myocardial infarction (STEMI) with primary percutaneous coronary intervention (PPCI). However, surrogate outcomes have shown inconsistent effects with lack of clinical correlation.

METHODS

We performed a registry-based randomised study of patients with STEMI allocated to RIC (4 cycles of blood pressure cuff inflation to 200 mm Hg for 5 min of ischaemia followed by 5 min of reperfusion) or standard of care (SOC) during PPCI. We examined the associations of RIC on core laboratory measurements of myocardial perfusion, infarct size (IS), left ventricular (LV) performance and clinical outcomes.

RESULTS

A total of 252 patients were enrolled. The median age was 61 (IQR: 55-70) years and 72.8% were male. Sum ST segment deviation resolution ≥50% was similar between RIC and SOC (65.2% vs 55.7%, p=0.269). In those with 3-day cardiovascular MRI (n=88), no difference in median (25th, 75th percentiles) IS (14.9% (4.5%, 23.1%) vs 16.1% (3.3%, 22.0%), p=0.980), LV dimensions (LV end-diastolic volume index: 78.7 (71.1, 91.2) mL/m² vs 79.9 (71.2, 88.8) mL/m², p=0.630; LV end-systolic volume index: 48.8 (35.7, 51.4) mL/m² vs 37.9 (31.8, 47.5) mL/m², p=0.551) or ejection fraction (50.0% (41.0%-55.0%) vs 50.0% (43.0%-56.0%), p=0.554) was demonstrated. Similar results were observed with 90-day cardiovascular MRI. At 1 year, the clinical composite of death, congestive heart failure, cardiogenic shock and recurrent myocardial infarction was similar in RIC and SOC (21.7% vs 13.3%, p=0.110).

CONCLUSIONS

In a contemporary registry-based randomised study of patients with STEMI undergoing PPCI, adjunctive therapy with RIC did not improve myocardial perfusion, reduce IS or alter LV performance. Consequently, there was no difference in clinical outcomes within 1 year.

TRIAL REGISTRATION NUMBER

NCT03930589.

Intravenous metoprolol during ongoing STEMI ameliorates markers of ischemic injury: a METOCARD-CNIC trial electrocardiographic study

Besides its protective effect against neutrophil-mediated injury at reperfusion, intravenous (IV) metoprolol was recently shown to reduce the progression of ischemic injury in a pig model of ST-segment elevation myocardial infarction (STEMI). Here, we tested the hypothesis that IV metoprolol administration in humans with ongoing STEMI blunts the time‑dependent progression of ischemic injury assessed by serial electrocardiogram (ECG) evaluations before reperfusion. The METOCARD-CNIC trial randomized 270 anterior STEMI patients to IV metoprolol or control before reperfusion by percutaneous coronary intervention (PCI). In 139 patients (69 IV metoprolol, 70 controls), two ECGs were available (ECG-1 before randomization, ECG-2 pre-PCI). Between-group ECG differences were analyzed using univariate and multivariate regression models. No significant between-group differences were observed on ECG-1. On ECG-2, patients who received IV metoprolol had a narrower QRS than those in the control group (84 ms vs. 90 ms, p = 0.029), a lower prevalence of QRS distortion (10% vs. 26%, p = 0.017), and a lower sum of anterior and total ST-segment elevation (10.1 mm vs. 13.6 mm, p = 0.014 and 10.4 mm vs. 14.0 mm, p = 0.015, respectively). Adjusted analysis revealed similar results. Significant associations were observed between ECG-2 variables and cardiac magnetic resonance imaging measurements (extent of myocardial edema, infarct size, microvascular obstruction, and left-ventricular ejection fraction) after STEMI. In summary, IV metoprolol administration before reperfusion ameliorates ECG markers of myocardial ischemia in anterior STEMI patients. These data confirm that IV metoprolol is able to reduce ischemic injury and highlight the ability of ECG analysis to provide relevant real-time information on the effect of cardioprotective therapies before reperfusion.

Reducing Cardiac Injury during ST-Elevation Myocardial Infarction: A Reasoned Approach to a Multitarget Therapeutic Strategy

The significant reduction in ‘ischemic time’ through capillary diffusion of primary percutaneous intervention (pPCI) has rendered myocardial-ischemia reperfusion injury (MIRI) prevention a major issue in order to improve the prognosis of ST elevation myocardial infarction (STEMI) patients. In fact, while the ischemic damage increases with the severity and the duration of blood flow reduction, reperfusion injury reaches its maximum with a moderate amount of ischemic injury. MIRI leads to the development of post-STEMI left ventricular remodeling (post-STEMI LVR), thereby increasing the risk of arrhythmias and heart failure. Single pharmacological and mechanical interventions have shown some benefits, but have not satisfactorily reduced mortality. Therefore, a multitarget therapeutic strategy is needed, but no univocal indications have come from the clinical trials performed so far. On the basis of the results of the consistent clinical studies analyzed in this review, we try to design a randomized clinical trial aimed at evaluating the effects of a reasoned multitarget therapeutic strategy on the prevention of post-STEMI LVR. In fact, we believe that the correct timing of pharmacological and mechanical intervention application, according to their specific ability to interfere with survival pathways, may significantly reduce the incidence of post-STEMI LVR and thus improve patient prognosis.

Morphine enhances LPS-induced macrophage apoptosis through a PPARγ-dependent mechanism

Morphine has been widely used for the treatment of pain and extensive studies have revealed a regulatory role for morphine in cell apoptosis. However, the molecular mechanisms underlying morphine-mediated apoptosis remain to be fully elucidated. The present study aimed to investigate the effects of morphine on lipopolysaccharide (LPS)-induced bone marrow-derived macrophage (BMDM) apoptosis and to determine the role of the peroxisome proliferator-activated receptor (PPAR)γ signaling pathway in this process. BMDMs were isolated from BALB/c mice and stimulated with LPS. Hoechst 33342 staining and flow cytometric analysis were performed to evaluate the effects of morphine on LPS-induced apoptosis of BMDMs. Caspase activity assays were used to determine the involvement of the apoptosis pathway. The expression levels of caspase-3, caspase-8, caspase-9 and PPARγ were analyzed using western blotting. Finally, GW9662, a specific PPARγ antagonist, was used to determine whether the regulatory effects of morphine on LPS-induced BMDM apoptosis were PPARγ-dependent. The results of the present study revealed that morphine increased the apoptosis of LPS-stimulated BMDMs. Morphine upregulated the expression levels and activity of caspase-3 in LPS-stimulated BMDMs, but downregulated the expression levels and activity of caspase-8. Morphine treatment also upregulated LPS-induced PPARγ expression levels in BMDMs. Finally, the stimulatory effects of morphine on LPS-induced apoptosis and caspase-3/9 activation were markedly reduced by GW9662. In conclusion, the findings of the present study indicated that morphine significantly promoted LPS-induced BMDM apoptosis and caspase-3/9 activation. These results suggested that the intrinsic pathway of apoptosis may be involved in the proapoptotic effects of morphine on LPS-stimulated BMDMs, which may be dependent, at least partially, on PPARγ activation.

Impact of Morphine Treatment With and Without Metoclopramide Coadministration on Myocardial and Microvascular Injury in Acute Myocardial Infarction: Insights From the Randomized MonAMI Trial

Background

Intravenous morphine administration can adversely affect platelet inhibition induced by P2Y₁₂ receptor inhibitors after acute myocardial infarction. In contrast, some evidence suggests that opioid agonists may have cardioprotective effects on the myocardium. The aim of this prospective, randomized MonAMI (Impact of Morphine Treatment With and Without Metoclopramide Coadministration on Platelet Inhibition in Acute Myocardial Infarction) trial was, therefore, to investigate the impact of morphine with or without metoclopramide coadministration on myocardial and microvascular injury.

Methods and Results

Patients with acute myocardial infarction (n=138) were assigned in a 1:1:1 ratio to ticagrelor 180 mg plus: (1) intravenous morphine 5 mg (morphine group); (2) intravenous morphine 5 mg and metoclopramide 10 mg (morphine+metoclopramide group); or (3) intravenous placebo (control group) administered before primary percutaneous coronary intervention. Cardiac magnetic resonance imaging was performed in 104 patients on day 1 to 4 after the index event. Infarct size was significantly smaller in the morphine only group as compared with controls (percentage of left ventricular mass, 15.5 versus 17.9; P=0.047). Furthermore, the number of patients with microvascular obstruction was significantly lower after morphine administration (28% versus 54%; P=0.022) and the extent of microvascular obstruction was smaller (percentage of left ventricular mass, 0 versus 0.74; P=0.037). In multivariable regression analysis, morphine administration was independently associated with a reduced risk for the occurrence of microvascular obstruction (odds ratio, 0.37; 95% CI, 0.14–0.93 [P=0.035]). There was no significant difference in infarct size (P=0.491) and extent (P=0.753) or presence (P=0.914) of microvascular obstruction when comparing the morphine+metoclopramide group with the control group.

Conclusions

In this randomized study, intravenous administration of morphine before primary percutaneous coronary intervention resulted in a significant reduction of myocardial and microvascular damage following acute myocardial infarction. This effect was not observed in the morphine plus metoclopramide group.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02627950.

Smoking, alcohol and opioids effect on coronary microcirculation: an update overview

Smoking, heavy alcohol drinking and drug abuse are detrimental lifestyle factors leading to loss of million years of healthy life annually. One of the major health complications caused by these substances is the development of cardiovascular diseases (CVD), which accounts for a significant proportion of substance-induced death. Smoking and excessive alcohol consumption are related to the higher risk of acute myocardial infarction. Similarly, opioid addiction, as one of the most commonly used substances worldwide, is associated with cardiac events such as ischemia and myocardial infarction (MI). As supported by many studies, coronary artery disease (CAD) is considered as a major cause for substance-induced cardiac events. Nonetheless, over the last three decades, a growing body of evidence indicates that a significant proportion of substance-induced cardiac ischemia or MI cases, do not manifest any signs of CAD. In the absence of CAD, the coronary microvascular dysfunction is believed to be the main underlying reason for CVD. To date, comprehensive literature reviews have been published on the clinicopathology of CAD caused by smoking and opioids, as well as macrovascular pathological features of the alcoholic cardiomyopathy. However, to the best of our knowledge there is no review article about the impact of these substances on the coronary microvascular network. Therefore, the present review will focus on the current understanding of the pathophysiological alterations in the coronary microcirculation triggered by smoking, alcohol and opioids.

Effect of COMBinAtion therapy with remote ischemic conditioning and exenatide on the Myocardial Infarct size: a two-by-two factorial randomized trial (COMBAT-MI)

Remote ischemic conditioning (RIC) and the GLP-1 analog exenatide activate different cardioprotective pathways and may have additive effects on infarct size (IS). Here, we aimed to assess the efficacy of RIC as compared with sham procedure, and of exenatide, as compared with placebo, and the interaction between both, to reduce IS in humans. We designed a two-by-two factorial, randomized controlled, blinded, multicenter, clinical trial. Patients with ST-segment elevation myocardial infarction receiving primary percutaneous coronary intervention (PPCI) within 6 h of symptoms were randomized to RIC or sham procedure and exenatide or matching placebo. The primary outcome was IS measured by late gadolinium enhancement in cardiac magnetic resonance performed 3-7 days after PPCI. The secondary outcomes were myocardial salvage index, transmurality index, left ventricular ejection fraction and relative microvascular obstruction volume. A total of 378 patients were randomly allocated, and after applying exclusion criteria, 222 patients were available for analysis. There were no significant interactions between the two randomization factors on the primary or secondary outcomes. IS was similar between groups for the RIC (24 ± 11.8% in the RIC group vs 23.7 ± 10.9% in the sham group, P = 0.827) and the exenatide hypotheses (25.1 ± 11.5% in the exenatide group vs 22.5 ± 10.9% in the placebo group, P = 0.092). There were no effects with either RIC or exenatide on the secondary outcomes. Unexpected adverse events or side effects of RIC and exenatide were not observed. In conclusion, neither RIC nor exenatide, or its combination, were able to reduce IS in STEMI patients when administered as an adjunct to PPCI.

Effects of morphine on P2Y12 platelet inhibitors in patients with acute myocardial infarction: A meta-analysis

OBJECTIVE

To explore the effects of morphine on P2Y₁₂ platelet inhibitors in patients with acute myocardial infarction (AMI).

METHODS

PubMed, Embase, Cochrane Library, and Web of Science were used to retrieve literature through 11th May 2019. Standardized weighted mean difference (SMD) and relative risk (RR) with 95% confidence intervals (CI), P-value, and I² value were used to assess the strength of the association in this meta-analysis. Outcomes included platelet reactivity, high residual platelet reactivity (HRPR), ticagrelor maximum concentration (Cmax), ticagrelor area under curve (AUC), death rate, reinfarction rate, stroke, stent thrombosis, thrombolysis in myocardial infarction (TIMI) hemorrhage, dyspnea, emesis, contrast-induced nephropathy, and pulmonary edema.

RESULTS

A total of 13 articles were included in this study, containing 5688 patients (morphine group: n = 2014, control group: n = 3674). Results illustrated that the morphine group had a higher platelet reactivity (SMD: 0.834, 95%CI: 0.483-1.186, P < 0.001) and HRPR rate (RR: 1.994, 95%CI: 1.536-2.588, P < 0.001) than the control group, while the Cmax of ticagrelor (WMD: -481.838, 95%CI: -841.242-122.434, P = 0.009) was lower than that of the control group. The death rate of the morphine group was lower than that in the control group (RR: 0.561, 95%CI: 0.337-0.933, P = 0.026). The morphine group had a higher emesis rate than the control group (RR: 4.486, 95%CI: 2.263-8.891, P < 0.001).

CONCLUSION

Morphine effectively suppresses the inhibition effect of P2Y₁₂ platelet inhibitors in patients with AMI.

Heart failure after myocardial infarction: incidence and predictors

Aims

The aim of the present paper was to provide an up‐to‐date view on epidemiology and risk factors of heart failure (HF) development after myocardial infarction.

Methods and results

Based on literature review, several clinical risk factors and biochemical, genetic, and imaging biomarkers were identified to predict the risk of HF development after myocardial infarction.

Conclusions

Heart failure is still a frequent complication of myocardial infarction. Timely identification of subjects at risk for HF development using a multimodality approach, and early initiation of guideline‐directed HF therapy in these patients, can decrease the HF burden.

Co-morbidities and co-medications as confounders of cardioprotection-Does it matter in the clinical setting?

The translation of cardioprotection from robust experimental evidence to beneficial clinical outcome for patients suffering acute myocardial infarction or undergoing cardiovascular surgery has been largely disappointing. The present review attempts to critically analyse the evidence for confounders of cardioprotection in patients with acute myocardial infarction and in patients undergoing cardiovascular surgery. One reason that has been proposed to be responsible for such lack of translation is the confounding of cardioprotection by co-morbidities and co-medications. Whereas there is solid experimental evidence for such confounding of cardioprotection by single co-morbidities and co-medications, the clinical evidence from retrospective analyses of the limited number of clinical data is less robust. The best evidence for interference of co-medications is that for platelet inhibitors to recruit cardioprotection per se and thus limit the potential for further protection from myocardial infarction and for propofol anaesthesia to negate the protection from remote ischaemic conditioning in cardiovascular surgery. LINKED ARTICLES: This article is part of a themed issue on Risk factors, comorbidities, and comedications in cardioprotection. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.23/issuetoc.

Morphine and myocardial ischaemia-reperfusion

Coronary heart disease (CHD) is a cardiovascular disease with high mortality and disability worldwide. The main pathological manifestation of CHD is myocardial injury due to ischaemia-reperfusion, resulting in the death of cardiomyocytes (apoptosis and necrosis) and the occurrence of cardiac failure. Morphine is a nonselective opioid receptor agonist that has been commonly used for analgesia and to treat ischaemic heart disease. The present review focused on morphine-induced protection in an animal model of myocardial ischaemia-reperfusion and chronic heart failure and the effects of morphine on ST segment elevation myocardial infarction (STEMI) patients who underwent pre-primary percutaneous coronary intervention (pre-PPCI) or PPCI. The signalling pathways involved are also briefly described.

Life-threatening arrhythmias in anterior ST-segment elevation myocardial infarction patients treated by percutaneous coronary intervention: adverse impact of morphine

AIMS

Important controversies remain concerning the determinants of life-threatening arrhythmias during ST-segment elevation myocardial infarction (STEMI) and their impact on late adverse events. This study sought to investigate which factors might facilitate ventricular tachycardia (VT) and ventricular fibrillation (VF), in a homogeneous population of anterior STEMI patients defined by abrupt left anterior descending coronary artery (LAD) occlusion and no collateral flow.

METHODS AND RESULTS

The 967 patients, who entered into the CIRCUS (Does Cyclosporine ImpRove Clinical oUtcome in ST elevation myocardial infarction patients) study, were assessed for further analysis. Acute VT/VF was defined as VT (run of tachycardia >30 s either self-terminated or requiring electrical/pharmacological cardioversion) or VF documented by electrocardiogram or cardiac monitoring, during transportation to the cathlab or initial hospitalization. VT/VF was documented in 136 patients (14.1%). Patients with VT/VF were younger and had shorter time from symptom onset to hospital arrival. Site of LAD occlusion, thrombus burden, area at risk, pre-percutaneous coronary intervention Thrombolysis in Myocardial Infarction flow, and ST-segment resolution were similar to that of patients without VT/VF. There was no impact of VT/VF on left ventricular remodelling or clinical outcomes. By multivariate analysis, the use of morphine (odds ratio 1.71; 95% confidence interval (1.13-2.60); P = 0.012) was the sole independent predictor of VT/VF occurrence.

CONCLUSIONS

In STEMI patients with LAD occlusion, our findings support the view that morphine could favour severe ventricular arrhythmias.

Comparison of infarction size, complete ST-segment resolution incidence, mortality and re-infarction and target vessel revascularization between remote ischemic conditioning and ischemic postconditioning in ST-segment elevation myocardial infarction patients undergoing primary percutaneous coronary intervention

Introduction

Due to higher morbidity and mortality, ST-segment elevation myocardial infarction (STEMI) causes many public health problems.

Aim

To observe effects of remote ischemic conditioning (RIC) and ischemic postconditioning (IPC) on patients diagnosed as STEMI undergoing primary percutaneous coronary intervention (pPCI).

Material and methods

This meta-analysis was conducted using indirect comparison by conducting a network meta-analysis (NMA). We conducted searches by utilizing PubMed and the other databases to identify randomized controlled trials (RCTs) that described IPC or RIC treated patients diagnosed with STEMI during processes of pPCI. Enzymatic infarct size and infarction size were evaluated and cardiac events were assessed during the follow-up.

Results

Pooled results showed that lower enzymatic infarction size was associated with the RIC group compared to the IPC group (IPC vs. RIC: standardized mean difference (SMD) = 1.126; 95% confidence interval (CI): 0.756–1.677). Compared with IPC, RIC significantly reduced infarction size, which was assessed using cardiac magnetic resonance (CMR) (SMD = 1.113; 95% CI: 0.674–1.837). We noted a potential toward greater complete ST-segment resolution in RIC patients compared with IPC patients (odds ratio (OR) = 0.821; 95% CI: 0.166–4.051). No significant difference existed in all-cause mortality (OR = 2.211; 95% CI: 0.845–5.784), Target vessel revascularization (TVR) (OR = 0.045; 95% CI: 0.001–.662) or re-infarction (OR = 1.763; 95% CI: 0.741–4.193).

Conclusions

This meta-analysis suggested RIC was correlated with significantly smaller infarction size compared to IPC. No significant superiority between RIC and IPC has been observed in this study on cSTR incidence, mortality and re-infarction or TVR.

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.

Serial assessment of focal myocardial function after percutaneous coronary intervention for ST-elevation myocardial infarction: Value of layer-specific speckle tracking echocardiography

BACKGROUND

Ischemia-reperfusion injury (IRI) frequently follows successful PCI for STEMI and is recognized by multiple modalities. Multilayer speckle tracking echocardiography (STE) has the potential of detecting myocardial dysfunction in different myocardial layers. Our objective was to describe the changes in layer-specific myocardial function over the 24 hours after successful PCI for ST-elevation myocardial infarction (STEMI).

METHODS

Patients (n = 120) with STEMI and no prior myocardial infarction underwent echocardiography prior to PCI, immediately after and at 3- and 24-hours post-PCI. Worsening focal dysfunction (WFD) was defined as an immediate reduction, compared to the pre-PCI value, in the amplitude of endo-myocardial longitudinal strain (endo-MLS) within the infarction territory.

RESULTS

Patients with WFD (52%) had further reductions in endo-MLS, mid-MLS, and epi-MLS in the infarction region immediately post-PCI; at 3 hours strain began to improve and continued to improve at 24 hours. Reductions of endo-MLS strain were more evident than those of global, mid-MLS, and epi-MLS. This same pattern was seen in each of the ischemic territories of the anterior descending, circumflex, and right coronary arteries. Immediate improvement in endo-MLS following PCI was seen in 48% of patients. The time from symptom onset to balloon time was markedly longer in those with WFD (P < .0001).

CONCLUSIONS

Multilayer SPE is a sensitive method that identifies serial alterations in focal myocardial function following successful PCI for STEMI. Layer-specific reductions in endo-MLS appeared more evident than decreases in global LV strain. Prolonged total ischemic time prior to PCI was directly related to the incidence of WFD.

Mechanical and Pharmacological Revascularization Strategies for Prevention of Microvascular Dysfunction in ST-Segment Elevation Myocardial Infarction: Analysis from Index of Microcirculatory Resistance Registry Data

Objectives

We aimed to identify mechanical and pharmacological revascularization strategies correlated with the index of microcirculatory resistance (IMR) in ST-elevation myocardial infarction (STEMI) patients.

Background

Microvascular dysfunction (MVD) after STEMI is correlated with infarct size and poor long-term prognosis, and the IMR is a useful analytical method for the quantitative assessment of MVD. However, therapeutic strategies that can reliably reduce MVD remain uncertain.

Methods

Patients with STEMI who underwent primary percutaneous coronary intervention (PCI) were enrolled. The IMR was measured with a pressure sensor/thermistor-tipped guidewire immediately after primary PCI. High IMR was defined as values ≥66^th percentile of IMR in enrolled patients (IMR > 30.9 IU).

Results

A total of 160 STEMI patients were analyzed (high IMR = 54 patients). Clinical factors for Killip class (P=0.006), delayed hospitalization from symptom onset (P=0.004), peak troponin-I level (P=0.042), and multivessel disease (P=0.003) were associated with high IMR. Achieving final thrombolysis in myocardial infarction myocardial perfusion grade 3 tended to be associated with low IMR (P=0.119), whereas the presence of distal embolization was significantly associated with high IMR (P=0.034). In terms of therapeutic strategies that involved adjusting clinical and angiographic factors associated with IMR, preloading of third-generation P2Y12 inhibitors correlated with reducing IMR value (β = −10.30, P < 0.001). Mechanical therapeutic strategies including stent diameter/length, preballoon dilatation, direct stenting, and thrombectomy were not associated with low IMR value (all P > 0.05), and postballoon dilatation was associated with high IMR (β = 8.30, P=0.020).

Conclusions

In our study, mechanical strategies were suboptimal in achieving myocardial salvage. Preloading of third-generation P2Y12 inhibitors revealed decreased IMR value, indicative of MVD prevention.

Myocardial ischaemia-reperfusion injury and cardioprotection in perspective

Despite the increasing use and success of interventional coronary reperfusion strategies, morbidity and mortality from acute myocardial infarction are still substantial. Myocardial infarct size is a major determinant of prognosis in these patients. Therefore, cardioprotective strategies aim to reduce infarct size. However, a perplexing gap exists between the many preclinical studies reporting infarct size reduction with mechanical and pharmacological interventions and the poor translation into better clinical outcomes in patients. This Review revisits the pathophysiology of myocardial ischaemia-reperfusion injury, including the role of autophagy and forms of cell death such as necrosis, apoptosis, necroptosis and pyroptosis. Other cellular compartments in addition to cardiomyocytes are addressed, notably the coronary microcirculation. Preclinical and clinical research developments in mechanical and pharmacological approaches to induce cardioprotection, and their signal transduction pathways, are discussed. Additive cardioprotective interventions are advocated. For clinical translation into treatments for patients with acute myocardial infarction, who typically are of advanced age, have comorbidities and are receiving several medications, not only infarct size reduction but also attenuation of coronary microvascular obstruction, as well as longer-term targets including infarct repair and reverse remodelling, must be considered to improve patient outcomes. Future clinical trials must focus on patients who really need adjunct cardioprotection, that is, those with severe haemodynamic alterations.

Novel Findings and Therapeutic Targets on Cardioprotection of Ischemia/ Reperfusion Injury in STEMI

Acute ST-segment elevation myocardial infarction (STEMI) remains a leading cause of morbidity and mortality around the world. A large number of STEMI patients after the infarction gradually develop heart failure due to the infarcted myocardium. Timely reperfusion is essential to salvage ischemic myocardium from the infarction, but the restoration of coronary blood flow in the infarct-related artery itself induces myocardial injury and cardiomyocyte death, known as ischemia/reperfusion injury (IRI). The factors contributing to IRI in STEMI are complex, and microvascular obstruction, inflammation, release of reactive oxygen species, myocardial stunning, and activation of myocardial cell death are involved. Therefore, additional cardioprotection is required to prevent the heart from IRI. Although many mechanical conditioning procedures and pharmacological agents have been identified as effective cardioprotective approaches in animal studies, their translation into the clinical practice has been relatively disappointing due to a variety of reasons. With new emerging data on cardioprotection in STEMI over the past few years, it is mandatory to reevaluate the effectiveness of "old" cardioprotective interventions and highlight the novel therapeutic targets and new treatment strategies of cardioprotection.

Message in a Bottle: Upgrading Cardiac Repair into Rejuvenation

Ischaemic cardiac disease is associated with a loss of cardiomyocytes and an intrinsic lack of myocardial renewal. Recent work has shown that the heart retains limited cardiomyocyte proliferation, which remains inefficient when facing pathological conditions. While broadly active in the neonatal mammalian heart, this mechanism becomes quiescent soon after birth, suggesting loss of regenerative potential with maturation into adulthood. A key question is whether this temporary regenerative window can be enhanced via appropriate stimulation and further extended. Recently the search for novel therapeutic approaches for heart disease has centred on stem cell biology. The “paracrine effect” has been proposed as a promising strategy to boost endogenous reparative and regenerative mechanisms from within the cardiac tissue by exploiting the modulatory potential of soluble stem cell-secreted factors. As such, growing interest has been specifically addressed towards stem/progenitor cell-secreted extracellular vesicles (EVs), which can be easily isolated in vitro from cell-conditioned medium. This review will provide a comprehensive overview of the current paradigm on cardiac repair and regeneration, with a specific focus on the role and mechanism(s) of paracrine action of EVs from cardiac stromal progenitors as compared to exogenous stem cells in order to discuss the optimal choice for future therapy. In addition, the challenges to overcoming translational EV biology from bench to bedside for future cardiac regenerative medicine will be discussed.

Impact of Morphine Treatment on Infarct Size and Reperfusion Injury in Acute Reperfused ST-Elevation Myocardial Infarction

Current evidence regarding the effect of intravenous morphine administration on reperfusion injury and/or cardioprotection in patients with myocardial infarction is conflicting. The aim of this study was to evaluate the impact of morphine administration, on infarct size and reperfusion injury assessed by cardiac magnetic resonance imaging (CMR) in a large multicenter ST-elevation myocardial infarction (STEMI) population. In total, 734 STEMI patients reperfused by primary percutaneous coronary intervention <12 h after symptom onset underwent CMR imaging at eight centers for assessment of myocardial damage. Intravenous morphine administration was recorded in all patients. CMR was completed within one week after infarction using a standardized protocol. The clinical endpoint of the study was the occurrence of major adverse cardiac events (MACE) within 12 months after infarction. Intravenous morphine was administered in 61.8% (n = 454) of all patients. There were no differences in infarct size (17%LV, interquartile range [IQR] 8–25%LV versus 16%LV, IQR 8–26%LV, p = 0.67) and microvascular obstruction (p = 0.92) in patients with versus without morphine administration. In the subgroup of patients with early reperfusion within 120 min and reduced flow of the infarcted vessel (TIMI-flow ≤2 before PCI) morphine administration resulted in significantly smaller infarcts (12%LV, IQR 12–19 versus 19%LV, IQR 10–29, p = 0.035) and reduced microvascular obstruction (p = 0.003). Morphine administration had no effect on hard clinical endpoints (log-rank test p = 0.74) and was not an independent predictor of clinical outcome in Cox regression analysis. In our large multicenter CMR study, morphine administration did not have a negative effect on myocardial damage or clinical prognosis in acute reperfused STEMI. In patients, presenting early ( ≤120 min) morphine may have a cardioprotective effect as reflected by smaller infarcts; but this finding has to be assessed in further well-designed clinical studies

Irisin Improves Autophagy of Aged Hepatocytes via Increasing Telomerase Activity in Liver Injury

An aged liver has decreased reparative capacity during ischemia-reperfusion (IR) injury. A recent study showed that plasma irisin levels predict telomere length in healthy adults. The aim of the present study is to clarify the role of irisin, telomerase activity, and autophagy during hepatic IR in the elderly. To study this, hepatic IR was established in 22-month- and 3-month-old rats and primary hepatocytes were isolated. The results showed that the old rats exhibited more serious liver injury and lower levels of irisin expression, telomerase activity, autophagy ability, and mitochondrial function than young rats during hepatic IR. Irisin activated autophagy and improved mitochondrial function via increasing telomerase activity in aged hepatocytes. Inhibition of telomerase activity by BIBP1532 abolished the protective role of irisin in hepatocytes during hypoxia and reoxygenation. Additionally, this study proved irisin increased the telomerase activity via inhibition of the phosphorylation of JNK during hepatic IR. Administration of exogenous irisin significantly mitigated the inflammation, oxidative stress, apoptosis, and liver injury in an old rat model of hepatic IR. In conclusion, irisin improves autophagy of aged hepatocytes via increasing telomerase activity in hepatic IR. Irisin exhibits conspicuous benefits in increasing reparative capacity of an aged liver during hepatic IR.

Effect of remote ischaemic conditioning on clinical outcomes in patients with acute myocardial infarction (CONDI-2/ERIC-PPCI): a single-blind randomised controlled trial

BACKGROUND

Remote ischaemic conditioning with transient ischaemia and reperfusion applied to the arm has been shown to reduce myocardial infarct size in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). We investigated whether remote ischaemic conditioning could reduce the incidence of cardiac death and hospitalisation for heart failure at 12 months.

METHODS

We did an international investigator-initiated, prospective, single-blind, randomised controlled trial (CONDI-2/ERIC-PPCI) at 33 centres across the UK, Denmark, Spain, and Serbia. Patients (age >18 years) with suspected STEMI and who were eligible for PPCI were randomly allocated (1:1, stratified by centre with a permuted block method) to receive standard treatment (including a sham simulated remote ischaemic conditioning intervention at UK sites only) or remote ischaemic conditioning treatment (intermittent ischaemia and reperfusion applied to the arm through four cycles of 5-min inflation and 5-min deflation of an automated cuff device) before PPCI. Investigators responsible for data collection and outcome assessment were masked to treatment allocation. The primary combined endpoint was cardiac death or hospitalisation for heart failure at 12 months in the intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT02342522) and is completed.

FINDINGS

Between Nov 6, 2013, and March 31, 2018, 5401 patients were randomly allocated to either the control group (n=2701) or the remote ischaemic conditioning group (n=2700). After exclusion of patients upon hospital arrival or loss to follow-up, 2569 patients in the control group and 2546 in the intervention group were included in the intention-to-treat analysis. At 12 months post-PPCI, the Kaplan-Meier-estimated frequencies of cardiac death or hospitalisation for heart failure (the primary endpoint) were 220 (8·6%) patients in the control group and 239 (9·4%) in the remote ischaemic conditioning group (hazard ratio 1·10 [95% CI 0·91-1·32], p=0·32 for intervention versus control). No important unexpected adverse events or side effects of remote ischaemic conditioning were observed.

INTERPRETATION

Remote ischaemic conditioning does not improve clinical outcomes (cardiac death or hospitalisation for heart failure) at 12 months in patients with STEMI undergoing PPCI.

FUNDING

British Heart Foundation, University College London Hospitals/University College London Biomedical Research Centre, Danish Innovation Foundation, Novo Nordisk Foundation, TrygFonden.

Remote ischemic conditioning: a promising therapeutic intervention for multi-organ protection

Despite decades of formidable exploration, multi-organ ischemia-reperfusion injury (IRI) encountered, particularly amongst elderly patients with clinical scenarios, such as age-related arteriosclerotic vascular disease, heart surgery and organ transplantation, is still an unsettled conundrum that besets clinicians. Remote ischemic conditioning (RIC), delivered via transient, repetitive noninvasive IR interventions to distant organs or tissues, is regarded as an innovative approach against IRI. Based on the available evidence, RIC holds the potential of affording protection to multiple organs or tissues, which include not only the heart and brain, but also others that are likely susceptible to IRI, such as the kidney, lung, liver and skin. Neuronal and humoral signaling pathways appear to play requisite roles in the mechanisms of RIC-related beneficial effects, and these pathways also display inseparable interactions with each other. So far, several hurdles lying ahead of clinical translation that remain to be settled, such as establishment of biomarkers, modification of RIC regimen, and deep understanding of underlying minutiae through which RIC exerts its powerful function. As this approach has garnered an increasing interest, herein, we aim to encapsulate an overview of the basic concept and postulated protective mechanisms of RIC, highlight the main findings from proof-of-concept clinical studies in various clinical scenarios, and also to discuss potential obstacles that remain to be conquered. More well designed and comprehensive experimental work or clinical trials are warranted in future research to confirm whether RIC could be utilized as a non-invasive, inexpensive and efficient adjunct therapeutic intervention method for multi-organ protection.

Autonomic nervous system response to remote ischemic conditioning: heart rate variability assessment

Background

Remote ischemic conditioning (RIC) is a procedure applied in a limb for triggering endogenous protective pathways in distant organs, namely brain or heart. The underlying mechanisms of RIC are still not fully understood, and it is hypothesized they are mediated either by humoral factors, immune cells and/or the autonomic nervous system. Herein, heart rate variability (HRV) was used to evaluate the electrophysiological processes occurring in the heart during RIC and, in turn to assess the role of autonomic nervous system.

Methods

Healthy subjects were submitted to RIC protocol and electrocardiography (ECG) was used to evaluate HRV, by assessing the variability of time intervals between two consecutive heart beats. This is a pilot study based on the analysis of 18 ECG from healthy subjects submitted to RIC. HRV was characterized in three domains (time, frequency and non-linear features) that can be correlated with the autonomic nervous system function.

Results

RIC procedure increased significantly the non-linear parameter SD2, which is associated with long term HRV. This effect was observed in all subjects and in the senior (> 60 years-old) subset analysis. SD2 increase suggests an activation of both parasympathetic and sympathetic nervous system, namely via fast vagal response (parasympathetic) and the slow sympathetic response to the baroreceptors stimulation.

Conclusions

RIC procedure modulates both parasympathetic and sympathetic autonomic nervous system. Furthermore, this modulation is more pronounced in the senior subset of subjects. Therefore, the autonomic nervous system regulation could be one of the mechanisms for RIC therapeutic effectiveness.

Electronic supplementary material

The online version of this article (10.1186/s12872-019-1181-5) contains supplementary material, which is available to authorized users.

Influence of Cardiovascular Risk Factors, Comorbidities, Medication Use and Procedural Variables on Remote Ischemic Conditioning Efficacy in Patients with ST-Segment Elevation Myocardial Infarction

Remote ischemic conditioning (RIC) confers cardioprotection in patients with ST-segment elevation myocardial infarction (STEMI). Despite intense research, the translation of RIC into clinical practice remains a challenge. This may, at least partly, be due to confounding factors that may modify the efficacy of RIC. The present review focuses on cardiovascular risk factors, comorbidities, medication use and procedural variables which may modify the efficacy of RIC in patients with STEMI. Findings of such efficacy modifiers are based on subgroup and post-hoc analyses and thus hold risk of type I and II errors. Although findings from studies evaluating influencing factors are often ambiguous, some but not all studies suggest that smoking, non-statin use, infarct location, area-at-risk of infarction, pre-procedural Thrombolysis in Myocardial Infarction (TIMI) flow, ischemia duration and coronary collateral blood flow to the infarct-related artery may influence on the cardioprotective efficacy of RIC. Results from the on-going CONDI2/ERIC-PPCI trial will determine any clinical implications of RIC in the treatment of patients with STEMI and predefined subgroup analyses will give further insight into influencing factors on the efficacy of RIC.

Effect of morphine use on oral P2Y12 platelet inhibitors in acute myocardial infarction: Meta-analysis

BACKGROUND

Morphine is the recommended analgesic in acute myocardial infarction (AMI). This recommendation has come under scrutiny because of possible slow uptake of oral antiplatelet agents.

OBJECTIVE

We performed a meta-analysis of all available studies in AMI patients treated with prasugrel or ticagrelor (P2Y12 inhibitors) that reported use of morphine prior to loading the antiplatelet agents to critically assess the safety of co-administration of morphine and the newer P2Y12 inhibitors.

METHODS

Several sources were searched from inception to December 2017 with inclusion of eight studies, largely observational. Mean difference (MD) was calculated for continuous variables, and standardized mean difference (SMD) for platelet function was assessed by the various platelet assays, 2 h after the loading dose of oral P2Y12 inhibitors.

RESULTS

Higher platelet activity was noted among morphine group [SMD = 0.8, 95% confidence interval (CI) = 0.4-1.1, p < 0.01]. Morphine use caused higher odds of "high residual platelet reactivity" at 2 h (odds = 3.3, 95 %CI = 2.2-5.1, p < 0.01). Ticagrelor reached a lower plasma concentration in morphine group (MD = -481.8 ng/ml, 95% CI = -841.2 to -122.4 ng/ml, p < 0.01) with a higher vomiting rate (odds = 5.3, 95% CI = 2.5-11.1, p < 0.01). However, the composite of in-hospital mortality, stroke, and re-infarction was not significantly different between the groups (p = 0.83).

CONCLUSION

Co-administration of morphine with P2Y12 inhibitors possibly decreases their efficacy in platelet inhibition. However, this did not translate into higher adverse outcomes because of low event rates, inadequate for analysis. A large randomized study is needed to evaluate the narcotic-P2Y12 interaction.

Remote ischemic conditioning during primary percutaneous coronary intervention in patients with ST-segment elevation myocardial infarction: a systematic review and meta-analysis

Objective

This systematic review was designed to evaluate the efficacy of remote ischemic conditioning (RIC) with primary percutaneous coronary intervention (PCI) versus primary PCI alone for ST-segment elevation myocardial infarction (STEMI).

Search strategy

Computerized search for trials from PubMed, EMBASE, CENTRAL and Cochrane Database of Systematic Reviews databases.

Selection criteria

Trials investigating RIC plus primary PCI (group A) versus primary PCI alone (group B).

Outcome measures

Myocardial enzyme levels; left ventricular ejection fraction (LVEF); major adverse cardiac and cerebrovascular events (MACCEs); TIMI flow grade III; myocardial salvage index or infarct size per patients.

Results

In all, 14 studies involving 3165 subjects were included. There was a significant association of myocardial edema levels, myocardial salvage index and incidence of MACCEs in group A compared with group B (myocardial edema levels: SMD = − 0.36, 95% CI (− 0.59, − 0.13); myocardial salvage index: MD = 0.06, 95% CI (0.02, 0.10); MACCE: OR = 0.70, 95% CI (0.57, 0.85)). With regard to infarct size, TIMI flow grade III and LVEF, group A appeared to be equivalent with group B (infarct size: MD = − 1.67, 95% CI (− 3.46, 0.11); TIMI flow grade III: OR = 1.04, 95% CI (0.71, 1.52); LVEF: MD = 0.74, 95% CI (− 0.80, 2.28)).

Conclusion

RIC was associated with lower myocardial edema levels, myocardial salvage index and incidence of MACCE, while non-significant beneficial effect on infarct size, TIMI flow grade III or LVEF. These findings suggest that RIC is a promising adjunctive treatment to PCI for the prevention of reperfusion injury in STEMI patients.

Intra-coronary morphine versus placebo in the treatment of acute ST-segment elevation myocardial infarction: the MIAMI randomized controlled trial

BACKGROUND

Experimental studies suggest that morphine may protect the myocardium against ischemia-reperfusion injury by activating salvage kinase pathways. The objective of this two-center, randomized, double-blind, controlled trial was to assess potential cardioprotective effects of intra-coronary morphine in patients with ST-segment elevation myocardial infarction (STEMI) referred for primary percutaneous intervention.

METHODS

Ninety-one patients with STEMI were randomly assigned to intracoronary morphine (1 mg) or placebo at reperfusion of the culprit coronary artery. The primary endpoint was infarct size/left ventricular mass ratio assessed by magnetic resonance imaging on day 3-5. Secondary endpoints included the areas under the curve (AUC) for troponin T and creatine kinase over three days, left ventricular ejection fraction assessed by echocardiography on days 1 and 6, and clinical outcomes.

RESULTS

Infarct size/left ventricular mass ratio was not significantly reduced by intracoronary morphine compared to placebo (27.2% ± 15.0% vs. 30.5% ± 10.6%, respectively, p = 0.28). Troponin T and creatine kinase AUCs were similar in the two groups. Morphine did not improve left ventricular ejection fraction on day 1 (49.7 ± 10.3% vs. 49.3 ± 9.3% with placebo, p = 0.84) or day 6 (48.5 ± 10.2% vs. 49.0 ± 8.5% with placebo, p = 0.86). The number of major adverse cardiac events, including stent thrombosis, during the one-year follow-up was similar in the two groups.

CONCLUSIONS

Intracoronary morphine at reperfusion did not significantly reduce infarct size or improve left ventricular systolic function in patients with STEMI. Presence of comorbidities in some patients may contribute to explain these results.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01186445 (date of registration: August 23, 2010).

Effect of comprehensive remote ischemic conditioning in anterior ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention: Design and rationale of the CORIC-MI randomized trial

Remote ischemic conditioning (RIC) applied during or after ST-segment elevation myocardial infarction (STEMI) is currently the most promising adjuvant therapy to reduce reperfusion injury. Recent animal studies showed that RIC may help the myocardium recover if applied daily during the month after STEMI. The Comprehensive Remote Ischemic Conditioning in Myocardial Infarction (CORIC-MI) trial is a single-center randomized controlled study in which 200 patients undergoing primary percutaneous coronary intervention (PPCI) for anterior STEMI will be randomized in a 1:1 ratio into comprehensive RIC (CORIC) or no intervention (control) groups. CORIC consists of per-RIC (5 cycles of 5-minute ischemia and 5-minute reperfusion of the lower limb immediately after randomization and before reperfusion), post-RIC (5 cycles of 5-minute ischemia and 5-minute reperfusion of the lower limb immediately post-PPCI), and delayed RIC (5 cycles of 5-minute ischemia and 5-minute reperfusion of the lower limb once daily on 2-28 days). Primary endpoint is left ventricular ejection fraction assessed by cardiac magnetic resonance imaging at 30 days. Major secondary endpoints include infarct size and left ventricular volume assessed by cardiac magnetic resonance imaging at 30 days, left ventricular ejection fraction assessed by echocardiography, and major adverse cardiovascular events up to 12 months. This report presents the baseline characteristics of 93 patients (CORIC group, n = 49; control group, n = 44) enrolled into the study as of March 31, 2018. The CORIC-MI trial aims to test the hypothesis that CORIC will improve cardiac function and remodeling in patients with anterior STEMI undergoing PPCI.

Remote ischaemic conditioning for myocardial infarction or elective PCI: systematic review and meta-analyses of randomised trials

BACKGROUND

The efficacy of remote ischaemic conditioning in clinical trials of ST-segment elevation myocardial infarction (STEMI) or elective percutaneous coronary intervention is controversial. We aimed to systematically review and meta-analyse whether remote ischaemic conditioning reduces myocardial damage in those patients.

METHODS

We searched PubMed, Embase and Web of Science from inception until December 2017 for randomised clinical trials evaluating remote ischaemic conditioning versus a control group. Two independent reviewers extracted data of 23 trials (2118 patients with STEMI; 2048 patients undergoing elective percutaneous coronary intervention) which were meta-analysed using random-effects models.

RESULTS

Remote ischaemic conditioning reduced infarct size in STEMI patients when assessed by imaging (mean difference of infarct size as percentage of left ventricle -2.43, 95% confidence interval (CI) -4.37 to -0.48; P=0.01; I²=44%; n=925) or biomarkers related to myocardial injury (peak values of cardiac biomarker release reported as standardised mean difference -0.19, 95% CI -0.37 to -0.02; P=0.03; I²=58%; n=1483) and increased myocardial salvage index (mean difference 0.07, 95% CI 0.01 to 0.13; P=0.02; I²=49%; n= 636). Left ventricular ejection fraction was increased when assessed during the first days after STEMI (mean difference 1.53, 95% CI 0.23 to 2.83; P=0.02; I²=28%; n=1192). Remote ischaemic conditioning had no influence on biomarker values after elective percutaneous coronary intervention (standardised mean difference 0.06, 95% CI -0.17 to 0.30; P=0.59).

CONCLUSIONS

Despite a statistically significant reduction of myocardial damage in STEMI patients, the magnitude of the reduction was small and a significant impact on clinical events is unlikely. With respect to elective percutaneous coronary intervention, remote ischaemic conditioning had no influence on myocardial injury and its use is not supported by our analysis.

Clinical translation of myocardial conditioning

Rapid admission and acute interventional treatment combined with modern antithrombotic pharmacologic therapy have improved outcomes in patients with ST elevation myocardial infarction. The next major target to further advance outcomes needs to address ischemia-reperfusion injury, which may contribute significantly to the final infarct size and hence mortality and postinfarction heart failure. Mechanical conditioning strategies including local and remote ischemic pre-, per-, and postconditioning have demonstrated consistent cardioprotective capacities in experimental models of acute ischemia-reperfusion injury. Their translation to the clinical scenario has been challenging. At present, the most promising mechanical protection strategy of the heart seems to be remote ischemic conditioning, which increases myocardial salvage beyond acute reperfusion therapy. An additional aspect that has gained recent focus is the potential of extended conditioning strategies to improve physical rehabilitation not only after an acute ischemia-reperfusion event such as acute myocardial infarction and cardiac surgery but also in patients with heart failure. Experimental and preliminary clinical evidence suggests that remote ischemic conditioning may modify cardiac remodeling and additionally enhance skeletal muscle strength therapy to prevent muscle waste, known as an inherent component of a postoperative period and in heart failure. Blood flow restriction exercise and enhanced external counterpulsation may represent cardioprotective corollaries. Combined with exercise, remote ischemic conditioning or, alternatively, blood flow restriction exercise may be of aid in optimizing physical rehabilitation in populations that are not able to perform exercise practice at intensity levels required to promote optimal outcomes.

Novel targets and future strategies for acute cardioprotection: Position Paper of the European Society of Cardiology Working Group on Cellular Biology of the Heart

Ischaemic heart disease and the heart failure that often results, remain the leading causes of death and disability in Europe and worldwide. As such, in order to prevent heart failure and improve clinical outcomes in patients presenting with an acute ST-segment elevation myocardial infarction and patients undergoing coronary artery bypass graft surgery, novel therapies are required to protect the heart against the detrimental effects of acute ischaemia/reperfusion injury (IRI). During the last three decades, a wide variety of ischaemic conditioning strategies and pharmacological treatments have been tested in the clinic-however, their translation from experimental to clinical studies for improving patient outcomes has been both challenging and disappointing. Therefore, in this Position Paper of the European Society of Cardiology Working Group on Cellular Biology of the Heart, we critically analyse the current state of ischaemic conditioning in both the experimental and clinical settings, provide recommendations for improving its translation into the clinical setting, and highlight novel therapeutic targets and new treatment strategies for reducing acute myocardial IRI.

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.

Reflection of Cardioprotection by Remote Ischemic Perconditioning in Attenuated ST-Segment Elevation During Ongoing Coronary Occlusion in Pigs: Evidence for Cardioprotection From Ischemic Injury

RATIONALE

Reduction of infarct size by remote ischemic perconditioning (perRIC) is evident only after several hours reperfusion.

OBJECTIVE

To develop a potential real-time estimate of cardioprotection by perRIC, we have analyzed the time course of ST-segment elevation.

METHODS AND RESULTS

Anesthetized open-chest pigs were subjected to 60-minute coronary occlusion and 180-minute reperfusion (placebo; n=19). PerRIC (n=18; 4×5 min/5 min hindlimb occlusion/reperfusion) was induced 20 minutes after coronary occlusion. Regional myocardial blood flow was measured with microspheres, areas of no-reflow with thioflavin-S, area at risk with blue dye, and infarct size with triphenyl tetrazolium chloride staining. Phosphorylation of protein kinase B α/β/γ, extracellular signal-regulated kinase 1/2, and signal transducer and activator of transcription 3 was determined by Western blot. ST-segment elevation was analyzed in a V2-like ECG-lead at baseline, 5- and 55-minute coronary occlusion, and 10-, 30-, 60-, and 120-minute reperfusion. Transmural blood flow at 5-minute coronary occlusion was not different between perRIC (0.029±0.015 mL/min per gram; mean±SD) and placebo (0.024±0.018 mL/min per gram) as was area at risk (perRIC: 24±6% of the left ventricle; placebo: 21±4%). Areas of no-reflow tended to be smaller with perRIC (9±12% of area at risk versus 15±14% with placebo; P=0.13). Infarct size with perRIC was 23±12% of area at risk versus 40±11% with placebo (P<0.001). PerRIC increased phosphorylation of signal transducer and activator of transcription 3 at 120-minute reperfusion by 196±142% versus 109±120% with placebo (P=0.047). The time courses of ST-segment elevation in perRIC and placebo protocols, respectively, were different (P=0.017). With similar ST-segment elevation at 5-minute coronary occlusion (perRIC 282±34 µV; placebo 259±28 µV), partial recovery of ST-segment elevation between 5- and 55-minute coronary occlusion was more pronounced with perRIC than placebo (by 111±84 versus 15±94 µV; P=0.028).

CONCLUSION

Infarct size reduction by perRIC is reflected in the ST-segment elevation during coronary occlusion in pigs, supporting the notion of protection from ischemic injury.