Protective Effects of Ticagrelor on Myocardial Injury After Infarction

The Role of TPM3 in Protecting Cardiomyocyte from Hypoxia-Induced Injury via Cytoskeleton Stabilization

Ischemic heart disease (IHD) remains a major global health concern, with ischemia-reperfusion injury exacerbating myocardial damage despite therapeutic interventions. In this study, we investigated the role of tropomyosin 3 (TPM3) in protecting cardiomyocytes against hypoxia-induced injury and oxidative stress. Using the AC16 and H9c2 cell lines, we established a chemical hypoxia model by treating cells with cobalt chloride (CoCl2) to simulate low-oxygen conditions. We found that CoCl2 treatment significantly upregulated the expression of hypoxia-inducible factor 1 alpha (HIF-1α) in cardiomyocytes, indicating the successful induction of hypoxia. Subsequent morphological and biochemical analyses revealed that hypoxia altered cardiomyocyte morphology disrupted the cytoskeleton, and caused cellular damage, accompanied by increased lactate dehydrogenase (LDH) release and malondialdehyde (MDA) levels, and decreased superoxide dismutase (SOD) activity, indicative of oxidative stress. Lentivirus-mediated TPM3 overexpression attenuated hypoxia-induced morphological changes, cellular damage, and oxidative stress imbalance, while TPM3 knockdown exacerbated these effects. Furthermore, treatment with the HDAC1 inhibitor MGCD0103 partially reversed the exacerbation of hypoxia-induced injury caused by TPM3 knockdown. Protein-protein interaction (PPI) network and functional enrichment analysis suggested that TPM3 may modulate cardiac muscle development, contraction, and adrenergic signaling pathways. In conclusion, our findings highlight the therapeutic potential of TPM3 modulation in mitigating hypoxia-associated cardiac injury, suggesting a promising avenue for the treatment of ischemic heart disease and other hypoxia-related cardiac pathologies.

The pig as an optimal animal model for cardiovascular research

Cardiovascular disease is a worldwide health problem and a leading cause of morbidity and mortality. Preclinical cardiovascular research using animals is needed to explore potential targets and therapeutic options. Compared with rodents, pigs have many advantages, with their anatomy, physiology, metabolism and immune system being more similar to humans. Here we present an overview of the available pig models for cardiovascular diseases, discuss their advantages over other models and propose the concept of standardized models to improve translation to the clinical setting and control research costs.

Recombinant human soluble domain of CD39L3 and ticagrelor: cardioprotective effects in experimental myocardial infarction

BACKGROUND AND AIMS

The ecto-nucleoside triphosphate diphosphohydrolases of the CD39 family degrade ATP and ADP into AMP, which is converted into adenosine by the extracellular CD73/ecto-5-nucleotidase. This pathway has been explored in antithrombotic treatments but little in myocardial protection. We have investigated whether the administration of solCD39L3 (AZD3366) confers additional cardioprotection to that of ticagrelor alone in a pre-clinical model of myocardial infarction (MI).

METHODS

Ticagrelor-treated pigs underwent balloon-induced MI (90 min) and, before reperfusion, received intravenously either vehicle, 1 mg/kg AZD3366 or 3 mg/kg AZD3366. All animals received ticagrelor twice daily for 42 days. A non-treated MI group was run as a control. Serial cardiac magnetic resonance (baseline, Day 3 and Day 42 post-MI), light transmittance aggregometry, bleeding time, and histological and molecular analyses were performed.

RESULTS

Ticagrelor reduced oedema formation and infarct size at Day 3 post-MI vs. controls. A 3 mg/kg AZD3366 provided an additional 45% reduction in oedema and infarct size compared with ticagrelor and a 70% reduction vs. controls (P < .05). At Day 42, infarct size declined in all ticagrelor-administered pigs, particularly in 3 mg/kg AZD3366-treated pigs (P < .05). Left ventricular ejection fraction was diminished at Day 3 in placebo pigs and worsened at Day 42, whereas it remained unaltered in ticagrelor ± AZD3366-administered animals. Pigs administered with 3 mg/kg AZD3366 displayed higher left ventricular ejection fraction upon dobutamine stress at Day 3 and minimal dysfunctional segmental contraction at Day 42 (χ2P < .05 vs. all). Cardiac and systemic molecular readouts supported these benefits. Interestingly, AZD3366 abolished ADP-induced light transmittance aggregometry without affecting bleeding time.

CONCLUSIONS

Infusion of AZD3366 on top of ticagrelor leads to enhanced cardioprotection compared with ticagrelor alone.

Ticagrelor enhances the cardioprotective effects of ischemic preconditioning in stable patients undergoing percutaneous coronary intervention: the TAPER-S randomized study

BACKGROUND

Ticagrelor improves clinical outcomes in patients with acute coronary syndromes compared with clopidogrel. Ticagrelor also inhibits cell uptake of adenosine and has been associated with cardioprotective effects in animal models. We sought to investigate the potential cardioprotective effects of ticagrelor, as compared with clopidogrel, in stable patients undergoing percutaneous coronary intervention (PCI).

METHODS AND RESULTS

This was a Prospective Randomized Open Blinded End-points (PROBE) trial enrolling stable patients with coronary artery disease (CAD) requiring fractional flow reserve-guided PCI of intermediate epicardial coronary lesions. ST-segment elevation at intracoronary electrocardiogram (IC-ECG) during a two-step sequential coronary balloon inflations in the reference vessel during PCI was used as an indirect marker of cardioprotection induced by ischemic preconditioning (IPC). The primary endpoint of the study was the comparison of the delta (Δ) (difference) ST-segment elevation measured by IC-ECG during two-step sequential coronary balloon inflations.

RESULTS

Fifty-three patients were randomized to either clopidogrel or ticagrelor. The study was stopped earlier because the primary endpoint was met at a pre-specified interim analysis. ΔST-segment elevation was significantly higher in ticagrelor as compared to clopidogrel arms (P < 0.0001). Ticagrelor was associated with lower angina score during coronary balloon inflations. There was no difference in coronary microvascular resistance between groups. Adenosine serum concentrations were increased in patients treated with ticagrelor as compared to those treated with clopidogrel.

CONCLUSIONS

Ticagrelor enhances the cardioprotective effects of IPC compared with clopidogrel in stable patients with CAD undergoing PCI. Further studies are warranted to fully elucidate the mechanisms through which ticagrelor may exert cardioprotective effects in humans.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov. Unique Identifier: NCT02701140.

Myocardial Ischemia-Reperfusion Injury: Unraveling Pathophysiology, Clinical Manifestations, and Emerging Prevention Strategies

Myocardial ischemia-reperfusion injury (MIRI) remains a challenge in the context of reperfusion procedures for myocardial infarction (MI). While early revascularization stands as the gold standard for mitigating myocardial injury, recent insights have illuminated the paradoxical role of reperfusion, giving rise to the phenomenon known as ischemia-reperfusion injury. This comprehensive review delves into the intricate pathophysiological pathways involved in MIRI, placing a particular focus on the pivotal role of endothelium. Beyond elucidating the molecular intricacies, we explore the diverse clinical manifestations associated with MIRI, underscoring its potential to contribute substantially to the final infarct size, up to 50%. We further navigate through current preventive approaches and highlight promising emerging strategies designed to counteract the devastating effects of the phenomenon. By synthesizing current knowledge and offering a perspective on evolving preventive interventions, this review serves as a valuable resource for clinicians and researchers engaged in the dynamic field of MIRI.

Off-Target Effects of P2Y12 Receptor Inhibitors: Focus on Early Myocardial Fibrosis Modulation

Several studies have demonstrated that, beyond their antithrombotic effects, P2Y12 receptor inhibitors may provide additional off-target effects through different mechanisms. These effects range from the preservation of endothelial barrier function to the modulation of inflammation or stabilization of atherosclerotic plaques, with an impact on different cell types, including endothelial and immune cells. Many P2Y12 inhibitors have been developed, from ticlopidine, the first thienopyridine, to the more potent non-thienopyridine derivatives such as ticagrelor which may promote cardioprotective effects following myocardial infarction (MI) by inhibiting adenosine reuptake through sodium-independent equilibrative nucleoside transporter 1 (ENT1). Adenosine may affect different molecular pathways involved in cardiac fibrosis, such as the Wnt (wingless-type)/beta (β)-catenin signaling. An early pro-fibrotic response of the epicardium and activation of cardiac fibroblasts with the involvement of Wnt1 (wingless-type family member 1)/β-catenin, are critically required for preserving cardiac function after acute ischemic cardiac injury. This review discusses molecular signaling pathways involved in cardiac fibrosis post MI, focusing on the Wnt/β-catenin pathway, and the off-target effect of P2Y12 receptor inhibition. A potential role of ticagrelor was speculated in the early modulation of cardiac fibrosis, thanks to its off-target effect.

Angiographic Predictors of Viability During Intervention for a ST Elevation Myocardial Infarction

Objectives

This study aimed to identify angiographic features that would predict myocardial viability after coronary intervention for ST elevation myocardial infarction (STEMI).

Methods

This retrospective study included patients who attended Sultan Qaboos University Hospital, Muscat, Oman, between January and December 2019 with a STEMI.

Results

A total of 72 patients (61 male; mean age = 54.9 ± 12.7 years) were included in the study; 11 patients had evidence of non-viability on echocardiography. There were 13 patients with viable myocardium and 3 with non-viable myocardium who had a myocardial blush grade (MBG) of 2 or lower. Similarly, 10 patients with viability and 1 with non-viable myocardium had thrombolysis in myocardial infarction (TIMI) flow of 2 or lower in the infarct related artery (IRA). However, none of these were statistically significant. The TIMI flow in the IRA at the end of the procedure correlated with the MBG.

Conclusion

There were no clear angiographic features during primary angioplasty that could predict myocardial viability.

Platelet-Mediated Transfer of Cardioprotection by Remote Ischemic Conditioning and Its Abrogation by Aspirin But Not by Ticagrelor

PURPOSE

The role of platelets during myocardial ischemia/reperfusion (I/R) is ambivalent. They contribute to injury but also to cardioprotection. Repeated blood flow restriction and reperfusion in a tissue/organ remote from the heart (remote ischemic conditioning, RIC) reduce myocardial I/R injury and attenuate platelet activation. Whether or not platelets mediate RIC's cardioprotective signal is currently unclear.

METHODS AND RESULTS

Venous blood from healthy volunteers (without or with pretreatment of 500/1000 mg aspirin or 180 mg ticagrelor orally, 2-3 h before the study, n = 18 each) was collected before and after RIC (3 × 5 min blood pressure cuff inflation at 200 mmHg on the left upper arm/5 min deflation). Washed platelets were isolated. Platelet-poor plasma was used to prepare plasma-dialysates. Platelets (25 × 103/µL) or plasma-dialysates (1:10) prepared before and after RIC from untreated versus aspirin- or ticagrelor-pretreated volunteers, respectively, were infused into isolated buffer-perfused rat hearts. Hearts were subjected to global 30 min/120 min I/R. Infarct size was stained. Infarct size was less with infusion of platelets/plasma-dialysate after RIC (18 ± 7%/23 ± 9% of ventricular mass) than with platelets/plasma-dialysate before RIC (34 ± 7%/33 ± 8%). Aspirin pretreatment abrogated the transfer of RIC's cardioprotection by platelets (after/before RIC, 34 ± 7%/33 ± 7%) but only attenuated that by plasma-dialysate (after/before RIC, 26 ± 8%/32 ± 5%). Ticagrelor pretreatment induced an in vivo formation of cardioprotective factor(s) per se (platelets/plasma-dialysate before RIC, 26 ± 7%/26 ± 7%) but did not impact on RIC's cardioprotection by platelets/plasma-dialysate (20 ± 7%/21 ± 5%).

CONCLUSION

Platelets serve as carriers for RIC's cardioprotective signal through an aspirin-sensitive and thus cyclooxygenase-dependent mechanism. The P2Y12 inhibitor ticagrelor per se induces a humoral cardioprotective signal.

Translational large animal model of coronary microvascular embolism: characterization by serial cardiac magnetic resonance and histopathology

This study aimed to construct a large animal model of coronary microvascular embolism, and investigate whether it could mimic the clinical imaging phenotypes of myocardial hypoperfusion in patients with ST-segment elevation myocardial infarction (STEMI). Nine minipigs underwent percutaneous coronary embolization with microspheres, followed by cardiac magnetic resonance (CMR) on week 1, 2 and 4 post operation. Microvascular obstruction (MVO) was defined as the isolated hypointense core within the enhanced area on late gadolinium enhancement images, which evolved during a 4-week follow-up. Fibrotic fraction of the segments was measured by Masson trichrome staining using a panoramic analysis software. Iron deposit and macrophage infiltration were quantified based on Perl's blue and anti-CD163 staining, respectively. Seven out of 9 (77.8%) minipigs survived and completed all of the imaging follow-ups. Four out of 7 (57.1%) minipigs were identified as transmural infarct with MVO. The systolic wall thickening (SWT) of MVO zone was similar to that of infarct zone (P = 0.762). Histopathology revealed transmural deposition of collagen, with microvessels obstructed by microspheres. The fibrotic fraction of infarct with MVO segments was similar to that of infarct without MVO segments (P = 0.954). The fraction of iron deposit in infarct with MVO segments was higher than that of infarct without MVO segments (P < 0.05), but the fraction of macrophage infiltration between these two segments did not show statistical difference (P = 0.723). Large animal model of coronary microvascular embolism could mimic most clinical imaging phenotypes of myocardial hypoperfusion in patients with STEMI, demonstrated by serial CMR and histopathology.

What do we know about platelets in myocardial ischemia-reperfusion injury and why is it important?

Myocardial ischemia-reperfusion injury (MIRI), the joint result of ischemic injury and reperfusion injury, is associated with poor outcomes in patients with acute myocardial infarction undergoing primary percutaneous coronary intervention. Accumulating evidence demonstrates that activated platelets directly contribute to the pathogenesis of MIRI through participating in the formation of microthrombi, interaction with leukocytes, secretion of active substances, constriction of microvasculature, and activation of spinal afferent nerves. The molecular mechanisms underlying the above detrimental effects of activated platelets include the homotypic and heterotypic interactions through surface receptors, transduction of intracellular signals, and secretion of active substances. Revealing the roles of platelet activation in MIRI and the associated mechanisms would provide potential targets/strategies for the clinical evaluation and treatment of MIRI. Further studies are needed to characterize the temporal (ischemia phase vs. reperfusion phase) and spatial (systemic vs. local) distributions of platelet activation in MIRI by multi-omics strategies. To improve the likelihood of translating novel cardioprotective interventions into clinical practice, basic researches maximally replicating the complexity of clinical scenarios would be necessary.

Ticagrelor Treatment is Associated With Increased Coronary Flow Reserve in Survivors of Myocardial Infarction

BACKGROUND

The pleiotropic action of ticagrelor, with effects in addition to platelet inhibition, has been shown to improve endothelial function in patients with coronary artery disease. These positive effects are possibly adenosine mediated. This study investigated the association of ticagrelor therapy and coronary artery flow reserve in survivors of myocardial infarction (MI).

METHODS

This was an exploratory, cross-sectional, open substudy of PROFLOW. High-risk individuals with a history of MI were identified. Coronary flow reserve (CFR) was measured non-invasively in the left anterior descending artery using transthoracic Doppler echocardiography. Coronary flow velocity was measured at rest and at maximal flow after induction of hyperaemia by intravenous infusion of adenosine at 140 μg/kg/min. Patients receiving ticagrelor (n=75) were compared with those not receiving ticagrelor (n=506), using simple and multiple linear regression models. Most patients in both groups were treated with aspirin (97% in the ticagrelor and 94% in the non-ticagrelor group). Adjustment for traditional risk factors was conducted.

RESULTS

The mean age at study inclusion was 68.5±6.8 years, and most patients were male (81.8%). The simple linear regression analysis showed ticagrelor treatment to be significantly associated with increased CFR: ticagrelor 2.95±0.76 (mean±SD), non-ticagrelor 2.70±0.77, (coefficient 0.25; 95% CI 0.063-0.438; p=0.009). This association was significant in two of the three multiple linear regression models with increasing numbers of variables: Model 1 (0.28; 0.06-0.50; p=0.014), Model 2 (0.26; 0.03-0.48; p=0.025), and borderline significant in Model 3 (0.21; -0.01 to 0.43; p=0.058).

CONCLUSIONS

Ticagrelor treatment was associated with increased CFR in this high-risk population. Increased CFR may be a clinically important therapeutic effect of ticagrelor in addition to platelet inhibition.

Extracellular vesicles mediate biological information delivery: A double-edged sword in cardiac remodeling after myocardial infarction

Acute myocardial infarction (AMI) is a severe ischemic disease with high morbidity and mortality worldwide. Maladaptive cardiac remodeling is a series of abnormalities in cardiac structure and function that occurs following myocardial infarction (MI). The pathophysiology of this process can be separated into two distinct phases: the initial inflammatory response, and the subsequent longer-term scar revision that includes the regression of inflammation, neovascularization, and fibrotic scar formation. Extracellular vesicles are nano-sized lipid bilayer vesicles released into the extracellular environment by eukaryotic cells, containing bioinformatic transmitters which are essential mediators of intercellular communication. EVs of different cellular origins play an essential role in cardiac remodeling after myocardial infarction. In this review, we first introduce the pathophysiology of post-infarction cardiac remodeling, as well as the biogenesis, classification, delivery, and functions of EVs. Then, we explore the dual role of these small molecule transmitters delivered by EVs in post-infarction cardiac remodeling, including the double-edged sword of pro-and anti-inflammation, and pro-and anti-fibrosis, which is significant for post-infarction cardiac repair. Finally, we discuss the pharmacological and engineered targeting of EVs for promoting heart repair after MI, thus revealing the potential value of targeted modulation of EVs and its use as a drug delivery vehicle in the therapeutic process of post-infarction cardiac remodeling.

Effect of ticagrelor and prasugrel on remote myocardial inflammation in patients with acute myocardial infarction with ST-elevation: a CMR T1 and T2 mapping study

PURPOSE

Acute myocardial ischaemia triggers a non-specific inflammatory response of remote myocardium through the increase of plasma concentrations of acute-phase proteins, which causes myocardial oedema. As ticagrelor has been shown to significantly decrease circulating levels of several pro-inflammatory cytokines in patients after acute myocardial infarction with ST-elevation (STEMI), we sought to investigate a potential suppressive effect of ticagrelor over prasugrel on cardiac magnetic resonance (CMR) T1 and T2 values in remote myocardium.

METHODS

Ninety STEMI patients were prospectively included and randomised to receive either ticagrelor or prasugrel maintenance treatment after successful primary percutaneous coronary intervention. Patients underwent CMR after 2-7 days. The protocol included long and short axis cine imaging, T1 mapping, T2 mapping and late gadolinium enhancement imaging.

RESULTS

After excluding 30 patients due to either missing images or insufficient quality of the T1 or T2 maps, 60 patients were included in our analysis. Of those, 29 patients were randomised to the ticagrelor group and 31 patients to the prasugrel group. In the remote myocardium, T1 values did not differ between groups (931.3 [919.4-950.4] ms for ticagrelor vs. 932.6 [915.5-949.2] ms for prasugrel (p = 0.94)), nor did the T2 values (53.8 ± 4.6 ms for ticagrelor vs. 53.7 ± 4.7 ms for prasugrel (p = 0.86)). Also, in the infarcted myocardium, T1 and T2 values did not differ between groups.

CONCLUSION

In revascularised STEMI patients, ticagrelor maintenance therapy did not show superiority over prasugrel in preventing early remote myocardial inflammation as assessed by CMR T1 and T2 mapping.

A Comprehensive Review of the Pleiotropic Effects of Ticagrelor

AIMS

This review summarizes the findings of preclinical studies evaluating the pleiotropic effects of ticagrelor. These include attenuation of ischemia-reperfusion injury (IRI), inflammation, adverse cardiac remodeling, and atherosclerosis. In doing so, it aims to provide novel insights into ticagrelor's mechanisms and benefits over other P2Y12 inhibitors. It also generates viable hypotheses for the results of seminal clinical trials assessing ticagrelor use in acute and chronic coronary syndromes.

METHODS AND RESULTS

A comprehensive review of the preclinical literature demonstrates that ticagrelor protects against IRI in the setting of both an acute myocardial infarction (MI), and when MI occurs while on chronic treatment. Maintenance therapy with ticagrelor also likely mitigates adverse inflammation, cardiac remodeling, and atherosclerosis, while improving stem cell recruitment. These effects are probably mediated by ticagrelor's ability to increase local interstitial adenosine levels which activate downstream cardio-protective molecules. Attenuation and augmentation of these pleiotropic effects by high-dose aspirin and caffeine, and statins respectively may help explain variable outcomes in PLATO and subsequent randomized controlled trials (RCTs).

CONCLUSION

Most RCTs and meta-analyses have not evaluated the pleiotropic effects of ticagrelor. We need further studies comparing cardiovascular outcomes in patients treated with ticagrelor versus other P2Y12 inhibitors that are mindful of the unique pleiotropic advantages afforded by ticagrelor, as well as possible interactions with other therapies (e.g., aspirin, statins, caffeine).

Platelets in Myocardial Ischemia/Reperfusion Injury

Coronary artery disease, including myocardial infarction (MI), remains a leading cause of global mortality. Rapid reperfusion therapy is key to the improvement of patient outcome but contributes substantially to the final cardiac damage. This phenomenon is called "ischemia/reperfusion injury (IRI)." The underlying mechanisms of IRI are complex and not fully understood. Contributing cellular and molecular mechanisms involve the formation of microthrombi, alterations in ion concentrations, pH shifts, dysregulation of osmolality, and, importantly, inflammation. Beyond their known action as drivers of the development of coronary plaques leading to MI, platelets have been identified as important mediators in myocardial IRI. Circulating platelets are activated by the IRI-provoked damages in the vascular endothelium. This leads to platelet adherence to the reperfused endothelium, aggregation, and the formation of microthrombi. Furthermore, activated platelets release vasoconstrictive substances, act via surface molecules, and enhance leukocyte infiltration into post-IR tissue, that is, via platelet-leukocyte complexes. A better understanding of platelet contributions to myocardial IRI, including their interaction with other lesion-associated cells, is necessary to develop effective treatment strategies to prevent IRI and further improve the condition of the reperfused myocardium. In this review, we briefly summarize platelet properties that modulate IRI. We also describe the beneficial impacts of antiplatelet agents as well as their mechanisms of action in IRI beyond classic effects.

Aquaporins: Important players in the cardiovascular pathophysiology

Aquaporin is a membrane channel protein widely expressed in body tissues, which can control the input and output of water in cells. AQPs are differentially expressed in different cardiovascular tissues and participate in water transmembrane transport, cell migration, metabolism, inflammatory response, etc. The aberrant expression of AQPs highly correlates with the onset of ischemic heart disease, myocardial ischemia-reperfusion injury, heart failure, etc. Despite much attention to the regulatory role of AQPs in the cardiovascular system, the translation of AQPs into clinical application still faces many challenges, including clarification of the localization of AQPs in the cardiovascular system and mechanisms mediating cardiovascular pathophysiology, as well as the development of cardiovascular-specific AQPs modulators.Therefore, in this study, we comprehensively reviewed the critical roles of AQP family proteins in maintaining cardiovascular homeostasis and described the underlying mechanisms by which AQPs mediated the outcomes of cardiovascular diseases. Meanwhile, AQPs serve as important therapeutic targets, which provide a wide range of opportunities to investigate the mechanisms of cardiovascular diseases and the treatment of those diseases.

Assessment of myocardial salvage in patients with STEMI undergoing thrombolysis: ticagrelor versus clopidogrel

Background

In the setting of ST-segment elevation myocardial infarction (STEMI), the faster and stronger antiplatelet action of ticagrelor compared to clopidogrel, as well as its pleiotropic effects, could result in a greater degree of cardioprotection and final infarct size (FIS) limitation. The aim of our study was to comparatively evaluate the effect of ticagrelor and clopidogrel on myocardial salvage index (MSI) in STEMI patients undergoing thrombolysis.

Methods

Forty-two STEMI patients treated with thrombolysis were randomized to receive clopidogrel (n = 21) or ticagrelor (n = 21), along with aspirin. Myocardial area at risk (AAR) was calculated according to the BARI and the APPROACH jeopardy scores. FIS was quantified by cardiac magnetic resonance imaging (CMR) performed 5–6 months post-randomization. MSI was calculated as (AAR-FIS)/AAR × 100%. Primary endpoint of our study was MSI. Secondary endpoints were FIS and CMR-derived left ventricular ejection fraction (LVEF) at 5 –6 months post-randomization.

Results

By using the BARI score for AAR calculation, mean MSI was 52.25 ± 30.5 for the clopidogrel group and 54.29 ± 31.08 for the ticagrelor group (p = 0.83), while mean MSI using the APPROACH score was calculated at 51.94 ± 30 and 53.09 ± 32.39 (p = 0.9), respectively. Median CMR-derived FIS—as a percentage of LV—was 10.7% ± 8.25 in the clopidogrel group and 12.09% ± 8.72 in the ticagrelor group (p = 0.6). Mean LVEF at 5–6 months post-randomization did not differ significantly between randomization groups.

Conclusions

Our results suggest that the administration of ticagrelor in STEMI patients undergoing thrombolysis offer a similar degree of myocardial salvage, compared to clopidogrel.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02735-1.

Supplementation With Spirulina Reduces Infarct Size and Ameliorates Cardiac Function in a Pig Model of STEMI

Background and Aims: Myocardial infarction (MI) is the clinical manifestation of atherosclerotic coronary artery disease. Spirulina is an algae known to ameliorate cardiometabolic disorders and with proven anti-inflammatory and anti-oxidant effects. We investigated, in a highly translatable animal model, whether oral supplementation with spirulina protects against the deleterious effects triggered by ST-elevation MI (STEMI). Methods: Pigs were fed a regular diet supplemented with spirulina (1 g/animal/bid) or placebo-control for 10 days. Thereafter, animals were subjected to 1.5 h percutaneous balloon-induced coronary occlusion (STEMI) followed by 2.5 h reperfusion and then sacrificed. We assessed infarct size and cardiac function. Blood samples and infarcted and remote myocardial tissue were obtained. Results: Spirulina supplementation reduced infarct size by 64%, increased myocardial salvage by 18%, and improved cardiac function by 30% vs. controls (p < 0.05). These benefits were associated with attenuation in DNA-oxidative damage and apoptotic markers and increased iNOS in the infarcted myocardium, higher AMPK activation in the remote myocardium, and lower myocardial MCP-1 expression. Systemically, spirulina attenuated Cox-2 expression in STEMI-activated peripheral blood mononuclear cells and enhanced TNF-α release acutely post-STEMI. Additionally, spirulina decreased weight gain progression over time (p < 0.05) without changes in lipids, glucose, liver or kidney parameters. Conclusion: A 10-day supplementation with spirulina exerts cardioprotection in a preclinical setting of STEMI by limiting cardiac damage and improving ventricular contractility through anti-oxidative, anti-inflammatory, and anti-apoptotic mechanisms.

Common Shared Pathogenic Aspects of Small Vessels in Heart and Brain Disease

Small-vessel disease (SVD), also known as microvascular endothelial dysfunction, is a disorder with negative consequences for various organs such as the heart and brain. Impaired dilatation and constriction of small vessels in the heart lead to reduced blood flow and ischemia independently of coronary artery disease (CAD) and are associated with major cardiac events. SVD is usually a silent form of subcortical vascular burden in the brain with various clinical manifestations, such as silent-lacunar-ischemic events and confluent white-matter hyperintensities. Imaging techniques are the main help for clinicians to diagnose cardiac and brain SVD correctly. Markers of inflammation, such as C-reactive protein, tumor-necrosis-factor α, and interleukin 6, provide insight into the disease and markers that negatively influence nitric-oxide bioavailability and promote oxidative stress. Unfortunately, the therapeutic approach against SVD is still not well-defined. In the last decades, various antioxidants, oxidative stress inhibitors, and superoxide scavengers have been the target of extensive investigations due to their potential therapeutic effect, but with unsatisfactory results. In clinical practice, traditional anti-ischemic and risk-reduction therapies for CAD are currently in use for SVD treatment.

Do We Really Need Aspirin Loading for STEMI?

Aspirin loading (chewable or intravenous) as soon as possible after presentation is a class I recommendation by current ST elevation myocardial infarction (STEMI) guidelines. Earlier achievement of therapeutic antiplatelet effects by aspirin loading has long been considered the standard of care. However, the effects of the loading dose of aspirin (alone or in addition to a chronic maintenance oral dose) have not been studied. A large proportion of myocardial cell death occurs upon and after reperfusion (reperfusion injury). Numerous agents and interventions have been shown to limit infarct size in animal models when administered before or immediately after reperfusion. However, these interventions have predominantly failed to show significant protection in clinical studies. In the current review, we raise the hypothesis that aspirin loading may be the culprit. Data obtained from animal models consistently show that statins, ticagrelor, opiates, and ischemic postconditioning limit myocardial infarct size. In most of these studies, aspirin was not administered. However, when aspirin was administered before reperfusion (as is the case in the majority of studies enrolling STEMI patients), the protective effects of statin, ticagrelor, morphine, and ischemic postconditioning were attenuated, which can be plausibly attributable to aspirin loading. We therefore suggest studying the effects of aspirin loading before reperfusion on the infarct size limiting effects of statins, ticagrelor, morphine, and/ or postconditioning in large animal models using long reperfusion periods (at least 24 h). If indeed aspirin attenuates the protective effects, clinical trials should be conducted comparing aspirin loading to alternative antiplatelet regimens without aspirin loading in patients with STEMI undergoing primary percutaneous coronary intervention.

Erythrocytes from patients with ST-elevation myocardial infarction induce cardioprotection through the purinergic P2Y13 receptor and nitric oxide signaling

Red blood cells (RBCs) are suggested to play a role in cardiovascular regulation by exporting nitric oxide (NO) bioactivity and ATP under hypoxia. It remains unknown whether such beneficial effects of RBCs are protective in patients with acute myocardial infarction. We investigated whether RBCs from patients with ST-elevation myocardial infarction (STEMI) protect against myocardial ischemia-reperfusion injury and whether such effect involves NO and purinergic signaling in the RBCs. RBCs from patients with STEMI undergoing primary coronary intervention and healthy controls were administered to isolated rat hearts subjected to global ischemia and reperfusion. Compared to RBCs from healthy controls, RBCs from STEMI patients reduced myocardial infarct size (30 ± 12% RBC healthy vs. 11 ± 5% RBC STEMI patients, P < 0.001), improved recovery of left-ventricular developed pressure and dP/dt and reduced left-ventricular end-diastolic pressure in hearts subjected to ischemia-reperfusion. Inhibition of RBC NO synthase with L-NAME or soluble guanylyl cyclase (sGC) with ODQ, and inhibition of cardiac protein kinase G (PKG) abolished the cardioprotective effect. Furthermore, the non-selective purinergic P2 receptor antagonist PPADS but not the P1 receptor antagonist 8PT attenuated the cardioprotection induced by RBCs from STEMI patients. The P2Y₁₃ receptor was expressed in RBCs and the cardioprotection was abolished by the P2Y₁₃ receptor antagonist MRS2211. By contrast, perfusion with PPADS, L-NAME, or ODQ prior to RBCs administration failed to block the cardioprotection induced by RBCs from STEMI patients. Administration of RBCs from healthy subjects following pre-incubation with an ATP analog reduced infarct size from 20 ± 6 to 7 ± 2% (P < 0.001), and this effect was abolished by ODQ and MRS2211. This study demonstrates a novel function of RBCs in STEMI patients providing protection against myocardial ischemia-reperfusion injury through the P2Y₁₃ receptor and the NO-sGC-PKG pathway.

P2Y12-dependent activation of hematopoietic stem and progenitor cells promotes emergency hematopoiesis after myocardial infarction

Emergency hematopoiesis is the driving force of the inflammatory response to myocardial infarction (MI). Increased proliferation of hematopoietic stem and progenitor cells (LSK) after MI enhances cell production in the bone marrow (BM) and replenishes leukocyte supply for local cell recruitment to the infarct. Decoding the regulation of the inflammatory cascade after MI may provide new avenues to improve post-MI remodeling. In this study, we describe the influence of adenosine diphosphate (ADP)-dependent P2Y₁₂-mediated signaling on emergency hematopoiesis and cardiac remodeling after MI. Permanent coronary ligation was performed to induce MI in a murine model. BM activation, inflammatory cell composition and cardiac function were assessed using global and platelet-specific gene knockout and pharmacological inhibition models for P2Y₁₂. Complementary in vitro studies allowed for investigation of ADP-dependent effects on LSK cells. We found that ADP acts as a danger signal for the hematopoietic BM and fosters emergency hematopoiesis by promoting Akt phosphorylation and cell cycle progression. We were able to detect P2Y₁₂ in LSK, implicating a direct effect of ADP on LSK via P2Y₁₂ signaling. P2Y₁₂ knockout and P2Y₁₂ inhibitor treatment with prasugrel reduced emergency hematopoiesis and the excessive inflammatory response to MI, translating to lower numbers of downstream progeny and inflammatory cells in the blood and infarct. Ultimately, P2Y₁₂ inhibition preserved cardiac function and reduced chronic adverse cardiac remodeling after MI. P2Y₁₂-dependent signaling is involved in emergency hematopoiesis after MI and fuels post-ischemic inflammation, proposing a novel, non-canonical value for P2Y₁₂ antagonists beyond inhibition of platelet-mediated atherothrombosis.

Changes in cardiac cells due to ticagrelor and enoxaparin in a rat ischemia/reperfusion model

OBJECTIVE

Studies on ischemia/reperfusion injury remain the focus of interest. Ticagrelor and enoxaparin, which are antiaggregant and anticoagulant drugs developed for use in many cardiovascular pathologies, are still included in many ischemia/reperfusion studies. Remarkably, their new protective effects, especially with regard to ticagrelor, continue to be reported in the current literature. The aim of this study was to evaluate the beneficial effects of ticagrelor and enoxaparin pretreatments on the rat heart with histological and immunohistochemical markers in an ischemia/reperfusion model.

METHODS

Wistar-albino rats (weighing 350-400 g) were divided into four groups as follows: Sham-Control (Group 1), Control-Saline+ischemia/reperfusion (Group 2), Ticagrelor+ischemia/reperfusion (Group 3), and Enoxaparin+ischemia/reperfusion (Group 4). The ischemia/reperfusion injury model was applied to Group 2, Group 3 and Group 4. Heart tissue sections were stained with hematoxylin and eosin for histological examinations. Caspase 3 immunostaining was evaluated to detect apoptosis in the heart tissue sections.

RESULTS

Both pretreatments ameliorated the ischemic damage but especially tissue sections belonging to Group 3 were nearly similar to control levels. The results indicated that ischemia/reperfusion-induced myocardial damage was significantly increased in Group 2, whereas ticagrelor and enoxaparin pretreatments in Group 3 and Group 4 significantly decreased apoptotic scores and the histological appearance of the Group 3 close to the normal myocardium (p<0.001).

CONCLUSION

As supported by histological findings in our study, ticagrelor and enoxaparin have protective properties for heart tissue in this ischemia/reperfusion injury model.

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.

Platelet Reactivity Was Not Associated with Infarct Size after Primary Percutaneous Coronary Intervention

Potent antiplatelet therapy after primary percutaneous coronary intervention (PCI) has the potential to reduce infarct size. This study analyzed the association between on-treatment platelet reactivity and myocardial infarct size in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary PCI. In this single-center, retrospective study, 253 patients who underwent primary PCI for STEMI were divided into two groups according to platelet reactivity measurements (53 patients in the high platelet reactivity [HPR] group and 200 in the non-HPR group). Technetium Tc-99m tetrofosmin single-photon emission computed tomography (SPECT) was performed before hospital discharge. We measured the infarct size using SPECT imaging and serial cardiac biomarker levels, and compared the infarct sizes of each group. The patients with HPR were older (65.5±13.2 vs. 60.6±12.1 years, p=0.011) than the patients with non-HPR. On the other hand, the non-HPR group had a higher incidence of smoking (26.4% vs. 51.0%, p=0.001) than the HPR group. Infarct size was similar between the two groups (22.6±17.3% vs. 24.8±17.7%, p=0.416). Multivariate analysis revealed that onset to balloon time >240 min (odds ratio [OR]=1.92; 95% confidence interval [CI]=1.08-3.40; p=0.025) and anterior infarction (OR=5.28; 95% CI=3.05-9.14; p<0.001) were independent predictors of large (>22%) infarct size. HPR was not a predictor of infarct size assessed by SPECT. The two groups also showed analogous cumulative creatinine kinase-myocardial band and troponin T levels. In conclusion, compared to non-HPR, HPR showed no significant association with myocardial infarct size measured by SPECT imaging in early phase of MI.

Glycosylated apolipoprotein J in cardiac ischaemia: molecular processing and circulating levels in patients with acute ischaemic events

AIM

Using proteomics, we previously found that serum levels of glycosylated (Glyc) forms of apolipoprotein J (ApoJ), a cytoprotective and anti-oxidant protein, decrease in the early phase of acute myocardial infarction (AMI). We aimed to investigate: (i) ApoJ-Glyc intracellular distribution and secretion during ischaemia; (ii) the early changes in circulating ApoJ-Glyc during AMI; and (iii) associations between ApoJ-Glyc and residual ischaemic risk post-AMI.

METHODS AND RESULTS

Glycosylated apolipoprotein J was investigated in: (i) cells from different organ/tissue origin; (ii) a pig model of AMI; (iii) de novo AMI patients (n = 38) at admission within the first 6 h of chest pain onset and without troponin T elevation at presentation (early AMI); (iv) ST-elevation myocardial infarction patients (n = 212) who were followed up for 6 months; and (v) a control group without any overt cardiovascular disease (n = 144). Inducing simulated ischaemia in isolated cardiac cells resulted in an increased intracellular accumulation of non-glycosylated ApoJ forms. A significant decrease in ApoJ-Glyc circulating levels was seen 15 min after ischaemia onset in pigs. Glycosylated apolipoprotein J levels showed a 45% decrease in early AMI patients compared with non-ischaemic patients (P < 0.0001), discriminating the presence of the ischaemic event (area under the curve: 0.934; P < 0.0001). ST-elevation myocardial infarction patients with lower ApoJ-Glyc levels at admission showed a higher rate of recurrent ischaemic events and mortality after 6-month follow-up (P = 0.008).

CONCLUSIONS

These results indicate that ischaemia induces an intracellular accumulation of non-glycosylated ApoJ and a reduction in ApoJ-Glyc secretion. Glycosylated apolipoprotein J circulating levels are reduced very early after ischaemia onset. Its continuous decrease indicates a worsening in the evolution of the cardiac event, likely identifying patients with sustained ischaemia after AMI.

Effect of Ticagrelor on Left Ventricular Remodeling in Patients With ST-Segment Elevation Myocardial Infarction (HEALING-AMI)

OBJECTIVES

The aim of this study was to evaluate the effect of ticagrelor versus clopidogrel on left ventricular (LV) remodeling after reperfusion of ST-segment elevation myocardial infarction (STEMI) in humans.

BACKGROUND

Animal studies have demonstrated that ticagrelor compared with clopidogrel better protects myocardium against reperfusion injury and improves remodeling after myocardial infarction.

METHODS

In this investigator-initiated, randomized, open-label, assessor-blinded trial performed at 10 centers in Korea, patients were enrolled if they had naive STEMI successfully treated with primary percutaneous coronary intervention (PCI) and at least 6-month planned duration of dual-antiplatelet treatment. The coprimary endpoints were LV remodeling index (LVRI) (a relative change of LV end-diastolic volume) measured on 3-dimensional echocardiography and N-terminal pro-B-type natriuretic peptide level at 6 months.

RESULTS

Among initially enrolled patients with STEMI (n = 336), 139 in each group completed the study. LVRI at 6 months was numerically lower with ticagrelor versus clopidogrel (0.6 ± 18.6% vs. 4.5 ± 16.5%; p = 0.095). Ticagrelor significantly reduced the 6-month level of N-terminal pro-B-type natriuretic peptide (173 ± 141 pg/ml vs. 289 ± 585 pg/ml; p = 0.028). These differences were prominent in patients with pre-PCI TIMI (Thrombolysis In Myocardial Infarction) flow grade 0. By multivariate analysis, ticagrelor versus clopidogrel reduced the risk for positive LV remodeling (LVRI >0%) (odds ratio: 0.56; 95% confidence interval: 0.33 to 0.95; p = 0.030). The LV end-diastolic volume index remained unchanged during ticagrelor treatment (from 54.7 ± 12.2 to 54.2 ± 12.2 ml/m²; p = 0.629), but this value increased over time during clopidogrel treatment (from 54.6 ± 11.3 to 56.4 ± 13.9 ml/m²; p = 0.056) (difference -2.3 ml/m²; 95% confidence interval: -4.8 to 0.2 ml/m²; p = 0.073). Ticagrelor reduced LV end-systolic volume index (from 27.0 ± 8.5 to 24.7 ± 8.4 ml/m²; p < 0.001), whereas no reduction was seen with clopidogrel (from 26.2 ± 8.9 to 25.6 ± 11.0 ml/m²; p = 0.366) (difference -1.8 ml/m²; 95% confidence interval: -3.5 to -0.1 ml/m²; p = 0.040).

CONCLUSIONS

Ticagrelor was superior to clopidogrel for LV remodeling after reperfusion of STEMI with primary PCI. (High Platelet Inhibition With Ticagrelor to Improve Left Ventricular Remodeling in Patients With ST Segment Elevation Myocardial Infarction [HEALING-AMI]; NCT02224534).

Antiplatelet Therapy with Integrated Traditional Chinese and Western Medicine for Use in Myocardial Ischemia-Reperfusion Injury: A Review of Clinical Applications and Mechanisms

Myocardial ischemia-reperfusion injury (MIRI) is common in patients with acute coronary syndrome (ACS) after PCI treatment, which seriously affects the efficacy of revascularization and hinders the postoperative recovery of patients; therefore, the current study is focused on determining effective methods in the treatment of MIRI. Antiplatelet therapy is a routine treatment for ACS, and its benefits for treating MIRI have been previously verified. With the development of traditional Chinese medicine (TCM), many TCM preparations are widely used in the clinic. Many basic and clinical studies have shown that TCM can be used together with antiplatelet drugs, and the safety and efficacy when TCM is included in the treatment are better than when antiplatelet drugs are used alone. This paper summarizes the current research progress of traditional Chinese medicine and Western medicine in the treatment of MIRI to provide a theoretical basis for further research and clinical treatment.

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.

Translation of experimental cardioprotective capability of P2Y12 inhibitors into clinical outcome in patients with ST-elevation myocardial infarction

We studied the translational cardioprotective potential of P2Y₁₂ inhibitors against acute myocardial ischemia/reperfusion injury (IRI) in an animal model of acute myocardial infarction and in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). P2Y₁₂ inhibitors may have pleiotropic effects to induce cardioprotection against acute myocardial IRI beyond their inhibitory effects on platelet aggregation. We compared the cardioprotective effects of clopidogrel, prasugrel, and ticagrelor on infarct size in an in vivo rat model of acute myocardial IRI, and investigated the effects of the P2Y₁₂ inhibitors on enzymatic infarct size (48-h area-under-the-curve (AUC) troponin T release) and clinical outcomes in a retrospective study of STEMI patients from the CONDI-2/ERIC-PPCI trial using propensity score analyses. Loading with ticagrelor in rats reduced infarct size after acute myocardial IRI compared to controls (37 ± 11% vs 52 ± 8%, p < 0.01), whereas clopidogrel and prasugrel did not (50 ± 11%, p > 0.99 and 49 ± 9%, p > 0.99, respectively). Correspondingly, troponin release was reduced in STEMI patients treated with ticagrelor compared to clopidogrel (adjusted 48-h AUC ratio: 0.67, 95% CI 0.47-0.94). Compared to clopidogrel, the composite endpoint of cardiac death or hospitalization for heart failure within 12 months was reduced in STEMI patients loaded with ticagrelor (HR 0.63; 95% CI 0.42-0.94) but not prasugrel (HR 0.84, 95% CI 0.43-1.63), prior to PPCI. Major adverse cardiovascular events did not differ between clopidogrel, ticagrelor, or prasugrel. The cardioprotective effects of ticagrelor in reducing infarct size may contribute to the clinical benefit observed in STEMI patients undergoing PPCI.

The pleiotropic effects of antithrombotic drugs in the metabolic-cardiovascular-neurodegenerative disease continuum: impact beyond reduced clotting

Antithrombotic drugs are widely used for primary and secondary prevention, as well as treatment of many cardiovascular disorders. Over the past few decades, major advances in the pharmacology of these agents have been made with the introduction of new drug classes as novel therapeutic options. Accumulating evidence indicates that the beneficial outcomes of some of these antithrombotic agents are not solely related to their ability to reduce thrombosis. Here, we review the evidence supporting established and potential pleiotropic effects of four novel classes of antithrombotic drugs, adenosine diphosphate (ADP) P2Y12-receptor antagonists, Glycoprotein IIb/IIIa receptor Inhibitors, and Direct Oral Anticoagulants (DOACs), which include Direct Factor Xa (FXa) and Direct Thrombin Inhibitors. Specifically, we discuss the molecular evidence supporting such pleiotropic effects in the context of cardiovascular disease (CVD) including endothelial dysfunction (ED), atherosclerosis, cardiac injury, stroke, and arrhythmia. Importantly, we highlight the role of DOACs in mitigating metabolic dysfunction-associated cardiovascular derangements. We also postulate that DOACs modulate perivascular adipose tissue inflammation and thus, may reverse cardiovascular dysfunction early in the course of the metabolic syndrome. In this regard, we argue that some antithrombotic agents can reverse the neurovascular damage in Alzheimer's and Parkinson's brain and following traumatic brain injury (TBI). Overall, we attempt to provide an up-to-date comprehensive review of the less-recognized, beneficial molecular aspects of antithrombotic therapy beyond reduced thrombus formation. We also make a solid argument for the need of further mechanistic analysis of the pleiotropic effects of antithrombotic drugs in the future.

Metabolomics identifying biomarkers of PM2.5 exposure for vulnerable population: based on a prospective cohort study

Long-term exposure to particular matter (PM), especially fine PM (< 2.5 μm in the aerodynamic diameter, PM_2.5), is associated with increased risk of cardiovascular disorders. This study aimed to evaluate the association between long-term exposure to PM_2.5/PM₁₀ and the metabolic change in the plasma. Specifically, using metabolomics, we sought to identify the biomarkers for the vulnerable subgroup to PM_2.5 exposure. A total of 78 college student volunteers were recruited into this prospective cohort study. All participants received 8 rounds of physical examinations at twice quarterly. Air purifiers were placed in 40 of 78 participants' dormitories for 14 days. Before and after intervention, physical examinations were performed and the peripheral blood was collected. Plasma metabolomics was determined by ultra-performance liquid chromatography-mass spectrometry. During the follow-up, the average concentrations of PM_2.5 and PM₁₀ were 53 μg/m³ and 93 μg/m³, respectively. Totally, 42 and 120 differential metabolic features were detected for PM₁₀ and PM_2.5 exposure, respectively. In total, 25 differential metabolites were identified for PM_2.5 exposure, most of which were phospholipids. No distinctive metabolites were found for PM₁₀ exposure. A total of 6 differential metabolites (lysoPC (P-20:0), lysoPC (P-18:1(9z)), lysoPC (20:1), lysoPC (O-16:0), choline, and found 1,3-diphenylprop-2-en-1-one) were characterized and confirmed for sensitive individuals. Importantly, we found LysoPC (P-20:0) and LysoPC (P-18:1(9z)) changed significantly before and after air purifier intervention. Our results indicated that the phospholipid catabolism was involved in long-term PM_2.5 exposure. LysoPC (P-20:0) and LysoPC (P-18:1(9z)) may be the biomarkers of PM_2.5 exposure.

Oxidative Stress in Ischemic Heart Disease

One of the novel interesting topics in the study of cardiovascular disease is the role of the oxidation system, since inflammation and oxidative stress are known to lead to cardiovascular diseases, their progression and complications. During decades of research, many complex interactions between agents of oxidative stress, oxidation, and antioxidant systems have been elucidated, and numerous important pathophysiological links to na number of disorders and diseases have been established. This review article will present the most relevant knowledge linking oxidative stress to vascular dysfunction and disease. The review will focus on the role of oxidative stress in endotheleial dysfunction, atherosclerosis, and other pathogenetic processes and mechanisms that contribute to the development of ischemic heart disease.

Intravenous Statin Administration During Myocardial Infarction Compared With Oral Post-Infarct Administration

BACKGROUND

Beyond lipid-lowering, statins exert cardioprotective effects. High-dose statin treatment seems to reduce cardiovascular complications in high-risk patients. The ideal timing and administration regime remain unknown.

OBJECTIVES

This study compared the cardioprotective effects of intravenous statin administration during myocardial infarction (MI) with oral administration immediately post-MI.

METHODS

Hypercholesterolemic pigs underwent MI induction (90 min of ischemia) and were kept for 42 days. Animals were distributed in 3 arms (A): A1 received an intravenous bolus of atorvastatin during MI; A2 received an intravenous bolus of vehicle during MI; and A3 received oral atorvastatin within 2 h post-MI. A1 and A3 remained on daily oral atorvastatin for the following 42 days. Cardiac magnetic resonance analysis (days 3 and 42 post-MI) and molecular/histological studies were performed.

RESULTS

At day 3, A1 showed a 10% reduction in infarct size compared with A3 and A2 and a 50% increase in myocardial salvage. At day 42, both A1 and A3 showed a significant decrease in scar size versus A2; however, A1 showed a further 24% reduction versus A3. Functional analyses revealed improved systolic performance in A1 compared with A2 and less wall motion abnormalities in the jeopardized myocardium versus both groups at day 42. A1 showed enhanced collagen content and AMP-activated protein kinase activation in the scar, increased vessel density in the penumbra, higher tumor necrosis factor α plasma levels and lower peripheral blood mononuclear cell activation versus both groups.

CONCLUSIONS

Intravenous administration of atorvastatin during MI limits cardiac damage, improves cardiac function, and mitigates remodeling to a larger extent than when administered orally shortly after reperfusion. This therapeutic approach deserves to be investigated in ST-segment elevation MI patients.

Ticagrelor Does Not Protect Against Endothelial Ischemia-Reperfusion Injury in Patients With Coronary Artery Disease

BACKGROUND

Ticagrelor is a recommended P2Y₁₂ receptor inhibitor after acute coronary syndrome (ACS). Its superiority has been suggested to rely on pleiotropic effects beyond platelet inhibition. Experimental studies indicate that ticagrelor may protect from ischemia-reperfusion injury but no data are available from such studies on patients. This study aimed to determine if chronic ticagrelor treatment protects against endothelial ischemia-reperfusion injury in patients with a previous ACS.

METHODS

Patients with a previous ACS were studied with flow mediated dilatation of the left brachial artery to determine the degree of endothelial ischemia-reperfusion injury before and after discontinuation of ticagrelor treatment, which had been continuous since 1 year. Each patient underwent 3 identical examinations. The first examination (Visit A) was at the end of ticagrelor treatment and the following 2 (Visit B and C) were after cessation of this treatment with an interval of 2 to 4 weeks.

RESULTS

Ischemia and reperfusion induced significant impairment of endothelial function at all 3 occasions (absolute decline in flow mediated dilatation 3.0% ± 0.7 at Visit A (P < 0.001), 1.9% ± 0.9 at Visit B (P < 0.05) and 1.9% ± 0.4 at Visit C (P < 0.0001)). However, there was no difference in the degree of endothelial ischemia-reperfusion injury or baseline endothelial function between the visits.

CONCLUSION

Chronic ticagrelor treatment in patients 1 year after an ACS does not protect against endothelial ischaemia-reperfusion injury. Nor is it associated with better basal endothelial function compared to after discontinuation of treatment.

ESC Working Group on Coronary Pathophysiology and Microcirculation position paper on 'coronary microvascular dysfunction in cardiovascular disease'

Although myocardial ischaemia usually manifests as a consequence of atherosclerosis-dependent obstructive epicardial coronary artery disease, a significant percentage of patients suffer ischaemic events in the absence of epicardial coronary artery obstruction. Experimental and clinical evidence highlight the abnormalities of the coronary microcirculation as a main cause of myocardial ischaemia in patients with 'normal or near normal' coronary arteries on angiography. Coronary microvascular disturbances have been associated with early stages of atherosclerosis even prior to any angiographic evidence of epicardial coronary stenosis, as well as to other cardiac pathologies such as myocardial hypertrophy and heart failure. The main objectives of the manuscript are (i) to provide updated evidence in our current understanding of the pathophysiological consequences of microvascular dysfunction in the heart; (ii) to report on the current knowledge on the relevance of cardiovascular risk factors and comorbid conditions for microcirculatory dysfunction; and (iii) to evidence the relevance of the clinical consequences of microvascular dysfunction. Highlighting the clinical importance of coronary microvascular dysfunction will open the field for research and the development of novel strategies for intervention will encourage early detection of subclinical disease and will help in the stratification of cardiovascular risk in agreement with the new concept of precision medicine.

Neuroprotection by remote ischemic conditioning in the setting of acute ischemic stroke: a preclinical two-centre study

Reperfusion is the only existing strategy for patients with acute ischemic stroke, however it causes further brain damage itself. A feasible therapy targeting reperfusion injury is remote ischemic conditioning (RIC). This was a two-centre, randomized, blinded international study, using translational imaging endpoints, aimed to examine the neuroprotective effects of RIC in ischemic stroke model. 80 male rats underwent 90-min middle cerebral artery occlusion. RIC consisted of 4 × 5 min cycles of left hind limb ischemia. The primary endpoint was infarct size measured on T2-weighted MRI at 24 h, expressed as percentage of the area-at-risk. Secondary endpoints were: hemispheric space-modifying edema, infarct growth between per-occlusion and 24 h MRI, neurofunctional outcome measured by neuroscores. 47 rats were included in the analysis after applying pre-defined inclusion criteria. RIC significantly reduced infarct size (median, interquartile range: 19% [8%; 32%] vs control: 40% [17%; 59%], p = 0.028). This effect was still significant after adjustment for apparent diffusion coefficient lesion size in multivariate analysis. RIC also improved neuroscores (6 [3; 8] vs control: 9 [7; 11], p = 0.032). Other secondary endpoints were not statistically different between groups. We conclude that RIC in the setting of acute ischemic stroke in rats is safe, reduces infarct size and improves functional recovery.

Cardioprotection for Acute MI in Light of the CONDI2/ERIC-PPCI Trial: New Targets Needed

Protection against ischaemia-reperfusion injury after revascularisation in acute myocardial infarction remains an enigma. Many targets have been identified, but after the failure of the recent Effect of Remote Ischaemic Conditioning on Clinical Outcomes in ST-elevation Myocardial Infarction Patients Undergoing Primary Percutaneous Coronary Intervention (CONDI2/ERIC-PPCI) trial to show translation to clinical benefit, there is still no pharmacological or mechanical strategy that has translated to clinical practice. This article addresses the results of the CONDI2/ERIC-PPCI trial in the context of previous studies of ischaemic conditioning, and then considers the prospects for other potential targets of cardioprotection. Finally, the authors examine the pitfalls and challenges in trial design for future investigation of cardioprotective strategies. In particular, this article highlights the need for careful endpoint and patient selection, as well as the need to pay attention to the biology of cardioprotection during the study.

Does the level of myocardial injury differ in primary angioplasty patients loaded first with clopidogrel and the ones with ticagrelor?

Objective:

In daily clinical practice, we encounter ST segment elevation myocardial infarction (STEMI) patients loaded with clopidogrel upon admission to primary angioplasty. These patients are loaded with ticagrelor, if there is no contraindication. This study aimed to compare the level of injury between STEMI patients who were first loaded with clopidogrel and the ones first loaded with ticagrelor. Although patients were switched from clopidogrel to ticagrelor at the first hour of angioplasty, antiplatelet action may still be lower than the others.

Methods:

This study included STEMI patients with angina onset of ≤3 h and who had primary angioplasty to proximal segment of one coronary artery. All patients had total thrombotic occlusion at the proximal segment. Δtroponin level (6^th-hour troponin–admission troponin) was calculated to compare the level of myocardial injury.

Results:

A total of 105 patients were included; 52 were loaded with ticagrelor and 53 with clopidogrel first and switched to ticagrelor. Baseline characteristics were similar in the two groups, except from type B2 lesions being more common in the ticagrelor-loaded group. Δtroponin levels were significantly higher in the clopidogrel-loaded group compared with the ticagrelor-loaded group (p=0.013). Major bleeding and in-hospital MACE rates were similar in both groups.

Conclusion:

In STEMI patients, the degree of troponin rise was more prominent in clopidogrel-loaded patients, despite the switch to ticagrelor in the first hour of intervention. Clopidogrel is slow and modest, and variable platelet inhibition may continue to be a negative factor for protection from myocardial injury, even after switching to ticagrelor.

Ticagrelor Conditioning Effects Are Not Additive to Cardioprotection Induced by Direct NLRP3 Inflammasome Inhibition: Role of RISK, NLRP3, and Redox Cascades

Inhibition of either P2Y12 receptor or the nucleotide-binding oligomerization domain- (NOD-) like receptor pyrin domain containing 3 (NLRP3) inflammasome provides cardioprotective effects. Here, we investigate whether direct NLRP3 inflammasome inhibition exerts additive effects on myocardial protection induced by the P2Y12 receptor antagonist Ticagrelor. Ticagrelor (150 mg/kg) was orally administered to rats for three consecutive days. Then, isolated hearts underwent an ischemia/reperfusion (30 min ischemia/60 min reperfusion; IR) protocol. The selective NLRP3 inflammasome inhibitor INF (50 μM) was infused before the IR protocol to the hearts from untreated animals or pretreated with Ticagrelor. In parallel experiments, the hearts isolated from untreated animals were perfused with Ticagrelor (3.70 μM) before ischemia and subjected to IR. The hearts of animals pretreated with Ticagrelor showed a significantly reduced infarct size (IS, 49 ± 3% of area at risk, AAR) when compared to control IR group (69 ± 2% of AAR). Similarly, ex vivo administration of INF before the IR injury resulted in significant IS reduction (38 ± 3% of AAR). Myocardial IR induced the NLRP3 inflammasome complex formation, which was attenuated by either INF pretreatment ex vivo, or by repeated oral treatment with Ticagrelor. The beneficial effects induced by either treatment were associated with the protective Reperfusion Injury Salvage Kinase (RISK) pathway activation and redox defence upregulation. In contrast, no protective effects nor NLRP3/RISK modulation were recorded when Ticagrelor was administered before ischemia in isolated heart, indicating that Ticagrelor direct target is not in the myocardium. Our results confirm that Ticagrelor conditioning effects are likely mediated through platelets, but are not additives to the ones achieved by directly inhibiting NLRP3.

Impact of Diabetes Mellitus and Chronic Kidney Disease on Cardiovascular Outcomes and Platelet P2Y12 Receptor Antagonist Effects in Patients With Acute Coronary Syndromes: Insights From the PLATO Trial

Background

There are limited data on how the combination of diabetes mellitus (DM) and chronic kidney disease (CKD) affects cardiovascular outcomes as well as response to different P2Y₁₂ receptor antagonists, which represented the aim of the present investigation.

Methods and Results

In this post hoc analysis of the PLATO (Platelet Inhibition and Patient Outcomes) trial, which randomized acute coronary syndrome patients to ticagrelor versus clopidogrel, patients (n=15 108) with available DM and CKD status were classified into 4 groups: DM+/CKD+ (n=1058), DM+/CKD− (n=2748), DM−/CKD+ (n=2160), and DM−/CKD− (n=9142). The primary efficacy end point was a composite of cardiovascular death, myocardial infarction, or stroke at 12 months. The primary safety end point was PLATO major bleeding. DM+/CKD+ patients had a higher incidence of the primary end point compared with DM−/CKD− patients (23.3% versus 7.1%; adjusted hazard ratio 2.22; 95% CI 1.88–2.63; P<0.001). Patients with DM+/CKD− and DM−/CKD+ had an intermediate risk profile. The same trend was shown for the individual components of the primary end point and for major bleeding. Compared with clopidogrel, ticagrelor reduced the incidence of the primary end point consistently across subgroups (P‐interaction=0.264), but with an increased absolute risk reduction in DM+/CKD+. The effects on major bleeding were also consistent across subgroups (P‐interaction=0.288).

Conclusions

In acute coronary syndrome patients, a gradient of risk was observed according to the presence or absence of DM and CKD, with patients having both risk factors at the highest risk. Although the ischemic benefit of ticagrelor over clopidogrel was consistent in all subgroups, the absolute risk reduction was greatest in patients with both DM and CKD.

Clinical Trial Registration

URL: http://www.clinicatrials.gov. Unique identifier: NCT00391872.

Targeted pharmacotherapy for ischemia reperfusion injury in acute myocardial infarction

INTRODUCTION

Achieving reperfusion immediately after acute myocardial infarction improves outcomes; despite this, patients remain at a high risk for mortality and morbidity at least for the first year after the event. Ischemia-reperfusion injury (IRI) has a complex pathophysiology and plays an important role in myocardial tissue injury, repair, and remodeling.

AREAS COVERED

In this review, the authors discuss the various mechanisms and their pharmacological agents currently available for reducing myocardial ischemia-reperfusion injury (IRI). They review important original investigations and trials in various clinical databases for treatments targeting IRI.

EXPERT OPINION

Encouraging results observed in many preclinical studies failed to show similar success in attenuating myocardial IRI in large-scale clinical trials. Identification of critical risk factors for IRI and targeting them individually rather than one size fits all approach should be the major focus of future research. Various newer therapies like tocilizumab, anakinra, colchicine, revacept, and therapies targeting the reperfusion injury salvage kinase pathway, survivor activating factor enhancement, mitochondrial pathways, and angiopoietin-like peptide 4 hold promise for the future.

Innate immunity as a target for acute cardioprotection

Acute obstruction of a coronary artery causes myocardial ischaemia and if prolonged, may result in an ST-segment elevation myocardial infarction (STEMI). First-line treatment involves rapid reperfusion. However, a highly dynamic and co-ordinated inflammatory response is rapidly mounted to repair and remove the injured cells which, paradoxically, can further exacerbate myocardial injury. Furthermore, although cardiac remodelling may initially preserve some function to the heart, it can lead over time to adverse remodelling and eventually heart failure. Since the size of the infarct corresponds to the subsequent risk of developing heart failure, it is important to find ways to limit initial infarct development. In this review, we focus on the role of the innate immune system in the acute response to ischaemia-reperfusion (IR) and specifically its contribution to cell death and myocardial infarction. Numerous danger-associated molecular patterns are released from dying cells in the myocardium, which can stimulate pattern recognition receptors including toll like receptors and NOD-like receptors (NLRs) in resident cardiac and immune cells. Activation of the NLRP3 inflammasome, caspase 1, and pyroptosis may ensue, particularly when the myocardium has been previously aggravated by the presence of comorbidities. Evidence will be discussed that suggests agents targeting innate immunity may be a promising means of protecting the hearts of STEMI patients against acute IR injury. However, the dosing and timing of such agents should be carefully determined because innate immunity pathways may also be involved in cardioprotection. This article is part of a Cardiovascular Research Spotlight Issue entitled 'Cardioprotection Beyond the Cardiomyocyte', and emerged as part of the discussions of the European Union (EU)-CARDIOPROTECTION Cooperation in Science and Technology (COST) Action, CA16225.

Ticagrelor Prevents Endothelial Cell Apoptosis through the Adenosine Signalling Pathway in the Early Stages of Hypoxia

BACKGROUND

Several studies have reported the beneficial effects of anti-platelet drugs in cardioprotection against ischaemia-reperfusion injuries. To date, no studies have focused on the indirect cytoprotective effects of ticagrelor via adenosine receptor on the endothelium.

METHOD

By evaluating cell viability and cleaved caspase 3 expression, we validated a model of endothelial cell apoptosis induced by hypoxia. In hypoxic endothelial cells treated with ticagrelor, we quantified the extracellular concentration of adenosine, and then we studied the involvement of adenosine pathways in the cytoprotective effect of ticagrelor.

RESULTS

Our results showed that 10 µM ticagrelor induced an anti-apoptotic effect in our model associated with an increase of extracellular adenosine concentration. Similar experiments were conducted with cangrelor but did not demonstrate an anti-apoptotic effect. We also found that A2B and A3 adenosine receptors were involved in the anti-apoptotic effect of ticagrelor in endothelial cells exposed to 2 h of hypoxia stress.

CONCLUSION

we described an endothelial cytoprotective mechanism of ticagrelor against hypoxia stress, independent of blood elements. We highlighted a mechanism triggered mainly by the increased extracellular bioavailability of adenosine, which activates A2B and A3 receptors on the endothelium.