Atherosclerotic Plaque Rupture Research Articles

A novel rabbit model of atherosclerotic vulnerable plaque established by cryofluid-induced endothelial injury

Acute thrombosis secondary to atherosclerotic plaque rupture is the main cause of acute cardiac and cerebral ischemia. An animal model of unstable atherosclerotic plaques is highly important for investigating the mechanism of plaque rupture and thrombosis. However, current animal models involve complex operations, are costly, and have plaque morphologies that are different from those of humans. We aimed to establish a simple animal model of vulnerable plaques similar to those of humans. Rabbits were randomly divided into three groups. Group A was given a normal formula diet for 13 weeks. Group C underwent surgery on the intima of the right carotid artery with – 80 °C cryofluid-induced injury after 1 week of a high-fat diet and further feeding a 12-week high-fat diet. Group B underwent the same procedure as Group C but without the – 80 °C cryofluid. Serum lipid levels were detected via ELISA. The plaque morphology, stability and degree of stenosis were evaluated through hematoxylin–eosin (HE) staining, Masson trichrome staining, Elastica van Gieson staining (EVG), and oil red O staining. Macrophages and inflammatory factors in the plaques were assessed via immunohistochemical analysis. The serum low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), and total cholesterol (TC) levels in groups B and C were significantly greater than those in group A. No plaque formation was observed in group A. The plaques in group B were very small. In group C, obvious plaques were observed in the blood vessels, and the plaques exhibited a thin fibrous cap, a large lipid core, and partially visible neovascularization, which is consistent with the characteristics of vulnerable plaques. In the plaques of group C, a large number of macrophages were present, and matrix metalloproteinase 9 (MMP-9) and lectin-like oxidized LDL receptor 1 (LOX-1) were abundantly expressed. We successfully established a rabbit model of vulnerable carotid plaque similar to that of humans through the combination of cryofluid-induced endothelial injury and a high-fat diet, which is feasible and cost effective.

Preventive percutaneous coronary intervention versus optimal medical therapy alone for the treatment of vulnerable atherosclerotic coronary plaques (PREVENT): a multicentre, open-label, randomised controlled trial

Acute coronary syndrome and sudden cardiac death are often caused by rupture and thrombosis of lipid-rich atherosclerotic coronary plaques (known as vulnerable plaques), many of which are non-flow-limiting. The safety and effectiveness of focal preventive therapy with percutaneous coronary intervention of vulnerable plaques in reducing adverse cardiac events are unknown. We aimed to assess whether preventive percutaneous coronary intervention of non-flow-limiting vulnerable plaques improves clinical outcomes compared with optimal medical therapy alone. PREVENT was a multicentre, open-label, randomised controlled trial done at 15 research hospitals in four countries (South Korea, Japan, Taiwan, and New Zealand). Patients aged 18 years or older with non-flow-limiting (fractional flow reserve >0·80) vulnerable coronary plaques identified by intracoronary imaging were randomly assigned (1:1) to either percutaneous coronary intervention plus optimal medical therapy or optimal medical therapy alone, in block sizes of 4 or 6, stratified by diabetes status and the performance of percutaneous coronary intervention in a non-study target vessel. Follow-up continued annually in all enrolled patients until the last enrolled patient reached 2 years after randomisation. The primary outcome was a composite of death from cardiac causes, target-vessel myocardial infarction, ischaemia-driven target-vessel revascularisation, or hospitalisation for unstable or progressive angina, assessed in the intention-to-treat population at 2 years. Time-to-first-event estimates were calculated with the Kaplan-Meier method and were compared with the log-rank test. This report is the principal analysis from the trial and includes all long-term analysed data. The trial is registered at ClinicalTrials.gov, NCT02316886, and is complete. Between Sept 23, 2015, and Sept 29, 2021, 5627 patients were screened for eligibility, 1606 of whom were enrolled and randomly assigned to percutaneous coronary intervention (n=803) or optimal medical therapy alone (n=803). 1177 (73%) patients were men and 429 (27%) were women. 2-year follow-up for the primary outcome assessment was completed in 1556 (97%) patients (percutaneous coronary intervention group n=780; optimal medical therapy group n=776). At 2 years, the primary outcome occurred in three (0·4%) patients in the percutaneous coronary intervention group and in 27 (3·4%) patients in the medical therapy group (absolute difference -3·0 percentage points [95% CI -4·4 to -1·8]; p=0·0003). The effect of preventive percutaneous coronary intervention was directionally consistent for each component of the primary composite outcome. Serious clinical or adverse events did not differ between the percutaneous coronary intervention group and the medical therapy group: at 2 years, four (0·5%) versus ten (1·3%) patients died (absolute difference -0·8 percentage points [95% CI -1·7 to 0·2]) and nine (1·1%) versus 13 (1·7%) patients had myocardial infarction (absolute difference -0·5 percentage points [-1·7 to 0·6]). In patients with non-flow-limiting vulnerable coronary plaques, preventive percutaneous coronary intervention reduced major adverse cardiac events arising from high-risk vulnerable plaques, compared with optimal medical therapy alone. Given that PREVENT is the first large trial to show the potential effect of the focal treatment for vulnerable plaques, these findings support consideration to expand indications for percutaneous coronary intervention to include non-flow-limiting, high-risk vulnerable plaques. The CardioVascular Research Foundation, Abbott, Yuhan Corp, CAH-Cordis, Philips, and Infraredx, a Nipro company.

CircHIPK3 targets DRP1 to mediate hydrogen peroxide-induced necroptosis of vascular smooth muscle cells and atherosclerotic vulnerable plaque formation

IntroductionNecroptosis triggered by H2O2 is hypothesized to be a critical factor in the rupture of atherosclerotic plaques, which may precipitate acute cardiovascular events. Nevertheless, the specific regulatory molecules of this development remain unclear. We aims to elucidate a mechanism from the perspective of circular RNA. ObjectivesThere are few studies on circRNA in VSMCs necroptosis. The objective of our research is to shed light on the intricate roles that circHIPK3 plays in the process of necroptosis in VSMCs and the development of atherosclerotic plaques that are prone to rupture. Our study elucidates the specific molecular mechanisms by which circHIPK3 regulates necroptosis and atherosclerotic vulnerable plaque formation through targeted proteins. Identifying this mechanism at the cellular level offers a molecular framework for understanding plaque progression and stability regulation, as well as a potential biomarker for the prognosis of susceptible atherosclerotic plaques. MethodsWe collected clinical vascular tissue for HE staining and Masson staining to determine the presence and stability of plaques. Then, NCBI database was used to screen out circRNA with elevated expression level in plaque tissue, and the up-regulated circRNA, circHIPK3, was verified by qRT-PCR and FISH. Further, we synthesized circHIPK3′s small interference sequence and overexpressed plasmid in vitro, and verified its regulation effect on necroptosis of VSMCs under physiological and pathological conditions by WB, qRT-PCR and PI staining. Through RNA pull down, mass spectrometry and RNA immunoprecipitation, DRP1 was identified as circHIPK3 binding protein and was positively regulated by circHIPK3. Meanwhile, on the basis of silencing of DRP1, the regulation of circHIPK3 on necroptosis is verified to be mediated by DRP1. Finally, we validated the regulation of circHIPK3 on vulnerable plaque formation in ApoE-/- mice. ResultsWe investigated that circHIPK3 was highly expressed in vulnerable plaques, and the increase in expression level promoted H2O2 induced necroptosis of VSMCs. CircHIPK3 targeted the protein DRP1, leading to an elevation in mitochondrial division rate, resulting in increased reactive oxygen species and impaired mitochondrial function, ultimately leading to necroptosis of VSMCs and vulnerable plaque formation. ConclusionCircHIPK3 interact with DRP1 involve in H2O2 induced Mitochondrial damage and necroptosis of VSMCs, and Silencing circHIPK3 in vivo can reduce atherosclerotic vulnerable plaque formation. Our research findings may have applications in providing diagnostic biomarkers for vulnerable plaques.

Measurement of Wall Shear Rate Across the Entire Vascular Wall Using Ultrasound Speckle Decorrelation

ObjectiveThe accurate measurement of the wall shear rate (WSR) plays a crucial role in the early diagnosis of cardiovascular disease progression and acute events such as aneurysms and atherosclerotic plaque ruptures. To address this need, the speckle decorrelation (SDC) technique has been used to measure WSR based on the 2-D out-of-plane blood flow speed. This technique is particularly advantageous because it enables the use of a 1-D array transducer to measure WSR over the entire luminal area. This study aims to develop a region-based singular value decomposition (SVD) filtering technique that selectively suppresses clutter noise in the vascular region to measure WSR using SDC. MethodUltrasound simulations, in-vitro flow experiments, and an in-vivo human study were conducted to evaluate the feasibility of this method's clinical application. ResultsThe results demonstrated that WSR can be effectively measured across entire vascular walls using a conventional 1-D array transducer along with the proposed methodology. ConclusionThis study successfully demonstrates a noninvasive and accurate SDC-based method for measuring vital vascular WSR. This approach holds significant promise for assessing vascular WSR in both healthy individuals and high-risk cardiovascular disease patients.

Impact of antiplatelet therapy on microvascular thrombosis during ST-elevation myocardial infarction.

During an acute coronary syndrome, atherosclerotic plaque rupture triggers platelet activation and thrombus formation, which may completely occlude a coronary artery leading to ST-elevation myocardial infarction (STEMI). Although emergency percutaneous coronary intervention (PCI) is effective in re-opening the main coronary arteries, the downstream microvasculature can become obstructed by embolised plaque material and thrombus. Dual antiplatelet therapy is recommended by guidelines and used routinely for the management of STEMI to reduce the risk of recurrent atherothrombotic events. However it is unclear to what extent antiplatelet therapy reduces microvascular thrombosis, largely because most tools to assess microvascular thrombosis only became available after antiplatelet therapy was already used in the majority of patients. Platelets play a central role in key aspects of microvascular thrombosis, such as atherosclerotic plaque-induced thrombus development, inflammation and microvascular dysfunction, making them a potential target for novel therapeutic interventions. Currently, more potent antiplatelet agents like GPIIb/IIIa inhibitors may be administered during PCI directly into coronary arteries with high thrombus burden but it is not well-established whether this reduces microvascular thrombosis and they significantly increase the risk of bleeding. In this review article we discuss the role of platelets in microvascular thrombosis, describe how microvascular thrombosis and obstruction can be assessed clinically and explore potential new antiplatelet treatments for this. In particular, we highlight novel antiplatelet drugs targeting the platelet receptor GPVI, as well as PAR4, GPIb-IX-V and 5HT2A receptors. We also discuss the potential benefit of P-selectin inhibitors as they have proven to be effective in reducing microvascular thrombosis in sickle-cell disease which could translate into potential benefits in acute coronary syndrome.

GPVI as an effective antithrombotic target.

Glycoprotein (GP) VI plays a major role in thrombosis but not haemostasis, making it a promising antithrombotic target. The primary role of GPVI on the surface of platelets is a signalling receptor for collagen, which is one of the most potent thrombotic sub-endothelial components that is exposed by atherosclerotic plaque rupture. Inhibition of GPVI has therefore been investigated as a strategy for treatment and prevention of atherothrombosis, such as during stroke and acute coronary syndromes. A range of specific GPVI inhibitors have been characterised and 2 of these inhibitors, glenzocimab and revacept, have completed phase II clinical trials in ischemic stroke. In this review, we summarise mechanisms of GPVI activation and the latest progress of clinically tested GPVI inhibitors, including their mechanisms of action. By focussing on what is known about GPVI activation, we also discuss whether alternate strategies could also be used to target GPVI.

In Situ Imaging of GGT and HOBr-Triggered Atherosclerotic Plaque Rupture via Activating the RunX2/Col IV Signaling Pathway.

Calcification and abnormal collagen deposition within blood vessels constitute causative factors for atherosclerotic plaque rupture, and their occurrence is intimately linked with γ-glutamyltranspeptidase (GGT) and hypobromous acid (HOBr). However, the underlying regulatory mechanisms of GGT and HOBr in plaque rupture remain unclear. Hence, we developed a dual-responsive near-infrared (NIR) fluorescent probe (BOC-H) that effectively avoids spectral crosstalk for the in situ visualization of the fluctuations in GGT and HOBr levels during atherosclerotic plaque rupture. We found that both GGT and HOBr contents increase significantly in the calcification models of cells and animals. The overexpressed GGT participated in intracellular oxygen-promoting behavior, which obviously upregulated the expression of RunX2 and Col IV by facilitating H2O2 and HOBr secretion. This process triggered calcification and abnormal collagen deposition within the plaque, which raised the risk of plaque rupture. PM2.5-induced arteriosclerotic calcification models further verified the results that GGT and HOBr accelerate plaque rupture via activation of the RunX2/Col IV signaling pathway. Moreover, the assessment of GGT and HOBr in serum samples from patients with acute myocardial infarction further confirmed the co-regulation of GGT and HOBr in the plaque rupture. Together, our studies highlight the involvement of GGT and HOBr in driving plaque rupture and offer new targets for the prevention and treatment of acute cardiovascular disease.

Mechanisms of Atherosclerotic Plaque Instability

Cardiovascular disease (CVD) is the leading cause of mortality in humans worldwide. The main cause of CVD is the formation of thrombi due to by unstable atherosclerotic plaque rupture on the arterial wall. Long-term accumulation of thrombi results in vascular remodeling, and subsequent-stenosis of the lumen obstructs the blood flow, thereby leading to myocardial tissue ischemia and hypoxia. Sustained ischemia and hypoxia lead to myocyte necrosis, resulting in irreversible myocardial injury. Many molecular and cellular mechanisms are associated with atherosclerotic plaque instability (API). For example, macrophages can produce various inflammatory factors, adhesion factors, chemokines and matrix metalloproteinases (MMPs), which play important roles in the pathophysiological mechanisms of API and in maintaining plaque stability. These molecules may help predict unstable atherosclerotic plaques. If the plaque is stable, it will not be prone to rupture or thrombosis. Accordingly, in this review, we will discuss the different pathophysiological mechanisms of API and the related roles of macrophages in the mechanisms of API mainly in animal models and humans. We believe this review will provide a theoretical basis for the development of treatments and diagnostic approaches for the management of API.

Biosensing Platforms for Cardiac Biomarker Detection.

Myocardial infarction (MI) is a cardiovascular disease that occurs when there is an elevated demand for myocardial oxygen as a result of the rupture or erosion of atherosclerotic plaques. Globally, the mortality rates associated with MI are steadily on the rise. Traditional diagnostic biomarkers employed in clinical settings for MI diagnosis have various drawbacks, prompting researchers to investigate fast, precise, and highly sensitive biosensor platforms and technologies. Biosensors are analytical devices that combine biological elements with physicochemical transducers to detect and quantify specific compounds or analytes. These devices play a crucial role in various fields including healthcare, environmental monitoring, food safety, and biotechnology. Biosensors developed for the detection of cardiac biomarkers are typically electrochemical, mass, and optical biosensors. Nanomaterials have emerged as revolutionary components in the field of biosensing, offering unique properties that significantly enhance the sensitivity and specificity of the detection systems. This review provides a comprehensive overview of the advancements and applications of nanomaterial-based biosensing systems. Beginning with an exploration of the fundamental principles governing nanomaterials, we delve into their diverse properties, including but not limited to electrical, optical, magnetic, and thermal characteristics. The integration of these nanomaterials as transducers in biosensors has paved the way for unprecedented developments in analytical techniques. Moreover, the principles and types of biosensors and their applications in cardiovascular disease diagnosis are explained in detail. The current biosensors for cardiac biomarker detection are also discussed, with an elaboration of the pros and cons of existing platforms and concluding with future perspectives.

Macrophage profiling in atherosclerosis: understanding the unstable plaque.

The development and rupture of atherosclerotic plaques is a major contributor to myocardial infarctions and ischemic strokes. The dynamic evolution of the plaque is largely attributed to monocyte/macrophage functions, which respond to various stimuli in the plaque microenvironment. To this end, macrophages play a central role in atherosclerotic lesions through the uptake of oxidized low-density lipoprotein that gets trapped in the artery wall, and the induction of an inflammatory response that can differentially affect the stability of the plaque in men and women. In this environment, macrophages can polarize towards pro-inflammatory M1 or anti-inflammatory M2 phenotypes, which represent the extremes of the polarization spectrum that include Mhem, M(Hb), Mox, and M4 populations. However, this traditional macrophage model paradigm has been redefined to include numerous immune and nonimmune cell clusters based on in-depth unbiased single-cell approaches. The goal of this review is to highlight (1) the phenotypic and functional properties of monocyte subsets in the circulation, and macrophage populations in atherosclerotic plaques, as well as their contribution towards stable or unstable phenotypes in men and women, and (2) single-cell RNA sequencing studies that have advanced our knowledge of immune, particularly macrophage signatures present in the atherosclerotic niche. We discuss the importance of performing high-dimensional approaches to facilitate the development of novel sex-specific immunotherapies that aim to reduce the risk of cardiovascular events.

Proteomic analysis of the extracellular matrix of human atherosclerotic plaques shows marked changes between plaque types

Cardiovascular disease is the leading cause of death, with atherosclerosis the major underlying cause. While often asymptomatic for decades, atherosclerotic plaque destabilization and rupture can arise suddenly and cause acute arterial occlusion or peripheral embolization resulting in myocardial infarction, stroke and lower limb ischaemia. As extracellular matrix (ECM) remodelling is associated with plaque instability, we hypothesized that the ECM composition would differ between plaques. We analyzed atherosclerotic plaques obtained from 21 patients who underwent carotid surgery following recent symptomatic carotid artery stenosis. Plaques were solubilized using a new efficient, single-step approach. Solubilized proteins were digested to peptides, and analyzed by liquid chromatography-mass spectrometry using data-independent acquisition. Identification and quantification of 4498 plaque proteins was achieved, including 354 ECM proteins, with unprecedented coverage and high reproducibility. Multidimensional scaling analysis and hierarchical clustering indicate two distinct clusters, which correlate with macroscopic plaque morphology (soft/unstable versus hard/stable), ultrasound classification (echolucent versus echogenic) and the presence of hemorrhage/ulceration. We identified 714 proteins with differential abundances between these groups. Soft/unstable plaques were enriched in proteins involved in inflammation, ECM remodelling, and protein degradation (e.g. matrix metalloproteinases, cathepsins). In contrast, hard/stable plaques contained higher levels of ECM structural proteins (e.g. collagens, versican, nidogens, biglycan, lumican, proteoglycan 4, mineralization proteins). These data indicate that a single-step proteomics method can provide unique mechanistic insights into ECM remodelling and inflammatory mechanisms within plaques that correlate with clinical parameters, and help rationalize plaque destabilization. These data also provide an approach towards identifying biomarkers for individualized risk profiling of atherosclerosis.

Fibrinogen and Intracoronary Thrombus as Predictors of Major Adverse Cardiovascular Events In-Hospital in St-Elevation Myocardial Infarction (STEMI) Patients Undergoing Primary Percutaneous Coronary Intervention

Background: Fibrinogen is an acute phase reactant involved in inflammation and coagulation in STEMI. Rupture of atherosclerotic plaque can cause the formation of intracoronary thrombus. Despite undergoing primary percutaneous coronary intervention (PCI), patients are at risk of experiencing major adverse cardiovascular events (MACE). Method: The research design used a prospective cohort. The independent variables are fibrinogen and intracoronary thrombus. Fibrinogen levels are examined when the patient arrives at the cardiac emergency unit. Intracoronary thrombus examination is carried out when the patient undergoes primary PCI. The outcomes studied were MACE during treatment in the form of cardiovascular death, cardiogenic shock, acute heart failure, malignant arrhythmias and persistent chest pain. Results: A total of 62 samples were involved in this research. There were 29 patients (46.7%) with high fibrinogen and 38 patients (61.3%) with large intracoronary thrombus. During follow-up during treatment, 26 patients (41.9%) experienced MACE. The cut-off fibrinogen value was 341.6 mg dl (AUC 0.809; 95% CI 0.696-0.923; p<0.001). Cox regression analysis using the backward log rank method showed that high fibrinogen (adjusted HR 3.45; 95% CI 1.29-9.23; p=0.13) and large intracoronary thrombus (adjusted HR 4.30; 95% CI 1.24-14.90; p=0.021) were independent predictors of MACE during hospitalization. Combined analysis of high fibrinogen and large intracoronary thrombus showed that 81.0% of patients experienced MACE during hospitalization (adjusted RR 2.87; 95% CI 1.12-7.35; Cohran and Mantel-Haenzel p=0.002). Conclusion: High fibrinogen and large intracoronary thrombus are independent predictors of MACE during hospitalization and can be applied as additional data for risk stratification in STEMI patients undergoing primary PCI.

Dual-modality probe nanodrug delivery systems with ROS-sensitivity for atherosclerosis diagnosis and therapy.

Most acute cardiovascular and cerebrovascular diseases are caused by atherosclerotic plaque rupture leading to blocked arteries. Targeted nanodelivery systems deliver imaging agents or drugs to target sites for diagnostic imaging or the treatment of various diseases, providing new insights for the detection and treatment of atherosclerosis. Based on the pathological characteristics of atherosclerosis, a hydrogen peroxide-sensitive bimodal probe PPIS@FC with integrated diagnosis and treatment function was designed. Bimodal probes Fe3O4@SiO2-CDs (FC) were prepared by coupling superparamagnetic iron oxide and carbon quantum dots synthesized with citric acid, and self-assembled with hydrogen peroxide stimulus-responsive amphiphilic block polymer PGMA-PEG modified with simvastatin (Sim) and target molecule ISO-1 to obtain drug-loaded micelles PGMA-PEG-ISO-1-Sim@FC (PPIS@FC). PPIS@FC could release Sim and FC in an H2O2-triggered manner, achieving the goal of releasing drugs using the special microenvironment at the plaque. At the same time, in vivo magnetic resonance and fluorescence imaging results proved that PPIS@FC possessed targeting ability, magnetic resonance imaging and fluorescence imaging effects. The results of the FeCl3 and ApoE-/- model showed that PPIS@FC had an excellent therapeutic effect and in vivo safety. Therefore, dual-modality imaging drug delivery systems with ROS response will become a promising strategy for the diagnosis and treatment of atherosclerosis.

Advances in MicroRNA-Mediated Regulation of Cardiomyocyte Injury After Coronary Microembolization

Coronary microembolization (CME) occurs in patients with acute coronary syndrome and is caused primarily by atherosclerotic plaque rupture associated with surgery. CME can lead to arrhythmias, decreased coronary blood flow reserve, and cardiac systolic dysfunction. The clinical efficacy of conventional coronary artery dilation, antiplatelet agents, and direct thrombus aspiration after CME is not satisfactory. Studies have indicated that microRNAs (miRNAs) specifically bind the 3′ untranslated regions (UTRs) of inflammatory response-, apoptosis-, and autophagy-related mRNAs, and ultimately affect CME prognosis. In-depth studies of the roles of miRNAs in CME occurrence and development would not only advance understanding of the mechanisms underlying poor prognosis after CME but also aid in identifying new targets for drug treatment. Here, we review the regulatory effects of miRNAs on myocardial cell injury after CME in terms of the inflammatory response, apoptosis, and autophagy. Overall, changes in miRNA levels after CME decrease myocardial autophagy and worsen cardiac prognosis. Current evidence suggests a potential strategic pathway for therapeutic intervention in CME management.

Diphenyl-tetrazol-propanamide Derivatives Act as Dual-Specific Antagonists of Platelet CLEC-2 and Glycoprotein VI.

Platelet C-type lectin-like receptor 2 (CLEC-2) induces platelet activation and aggregation after clustering by its ligand podoplanin (PDPN). PDPN, which is not normally expressed in cells in contact with blood flow, is induced in inflammatory immune cells and some malignant tumor cells, thereby increasing the risk of venous thromboembolism (VTE) and tumor metastasis. Therefore, small-molecule compounds that can interfere with the PDPN-CLEC-2 axis have the potential to become selective antiplatelet agents. Using molecular docking analysis of CLEC-2 and a PDPN-CLEC-2 binding-inhibition assay, we identified a group of diphenyl-tetrazol-propanamide derivatives as novel CLEC-2 inhibitors. A total of 12 hit compounds also inhibited PDPN-induced platelet aggregation in humans and mice. Unexpectedly, these compounds also fit the collagen-binding pocket of the glycoprotein VI molecule, thereby inhibiting collagen interaction. These compounds also inhibited collagen-induced platelet aggregation, and one compound ameliorated collagen-induced thrombocytopenia in mice. For clinical use, these compounds will require a degree of chemical modification to decrease albumin binding. Nonetheless, as dual activation of platelets by collagen and PDPN-positive cells is expected to occur after the rupture of atherosclerotic plaques, these dual antagonists could represent a promising pharmacophore, particularly for arterial thrombosis, in addition to VTE and metastasis.

MiR-223-3p Prevents Necroptotic Macrophage Death by Targeting Ripk3 in a Negative Feedback Loop and Consequently Ameliorates Advanced Atherosclerosis.

The formation of large necrotic cores results in vulnerable atherosclerotic plaques, which can lead to severe cardiovascular diseases. However, the specific regulatory mechanisms underlying the development of necrotic cores remain unclear. To evaluate how the modes of lesional cell death are reprogrammed during the development of atherosclerosis, the expression levels of key proteins that are involved in the necroptotic, apoptotic, and pyroptotic pathways were compared between different stages of plaques in humans and mice. Luciferase assays and loss-of-function studies were performed to identify the microRNA-mediated regulatory mechanism that protects foamy macrophages from necroptotic cell death. The role of this mechanism in atherosclerosis was determined by using a knockout mouse model with perivascular drug administration and tail vein injection of microRNA inhibitors in Apoe-/- mice. Here, we demonstrate that the necroptotic, rather than the apoptotic or pyroptotic, pathway is more activated in advanced unstable plaques compared with stable plaques in both humans and mice, which closely correlates with necrotic core formation. The upregulated expression of Ripk3 (receptor-interacting protein kinase 3) promotes the C/EBPβ (CCAAT/enhancer binding protein beta)-dependent transcription of the microRNA miR-223-3p, which conversely inhibits Ripk3 expression and forms a negative feedback loop to regulate the necroptosis of foamy macrophages. The knockout of the Mir223 gene in bone marrow cells accelerates atherosclerosis in Apoe-/- mice, but this effect can be rescued by Ripk3 deficiency or treatment with the necroptosis inhibitors necrostatin-1 and GSK-872. Like the Mir223 knockout, treating Apoe-/- mice with miR-223-3p inhibitors increases atherosclerosis. Our study suggests that miR-223-3p expression in macrophages protects against atherosclerotic plaque rupture by limiting the formation of necrotic cores, thus providing a potential microRNA therapeutic candidate for atherosclerosis.

C-reactive protein levels and coronary in-stent restenosis: A systematic review and meta-analysis

Abstract Background C-reactive protein (CRP) is an inflammatory biomarker and has been implicated in the pathogenesis of atherosclerotic lesion formation, plaque rupture, and coronary thrombosis. Its relationship to adverse angiographic outcomes after coronary stenting however remains uncertain. Purpose We aimed to test the association of baseline CRP levels with the incidence of coronary in-stent restenosis (ISR) using a systematic review and meta-analysis. Methods Relevant published studies were identified following a US National Institutes of Health (PubMed), EMBASE, MEDLINE, Scopus and Web of Knowledge databases search, until 31st October 2022. Selected studies had to be/have (i) original research with an angiographically determined ISR and an angiographically or clinically determined no-ISR group, and (ii) CRP levels measured before index stenting for both groups. Mean difference in CRP levels with its 95%CI between ISR and no-ISR was ascertained for each included study. Pooled standard mean difference (SMD) and its 95%CI was derived after pooling study level results using random effects employing a Z test. Begg’s funnel plots and Egger’s test were used for publication bias assessment. Results Amongst total of 1,009 unique results, 497 full-text articles were assessed for eligibility, 461 were excluded for a variety of reasons, which left 36 articles with 37 different studies (Nst= 37), with a total sample of 10,577 (2,122 ISR cases / 8,455 controls), to be included for quantitative synthesis. Complete study flow is depicted in Figure 1. ISR group had higher pooled CRP levels (Nst= 37, SMD= 0.50, 95% CI= 0.33, 0.67 mg/L, p< 0.00001) as compared to no-ISR group. Sensitivity analysis found no instance of significant alteration from the original results. No evidence of publication bias was detected either visually by the Begg’s funnel plots or the Egger’s test (p= 0.07). Analysis was repeated after subgroup stratification of the included studies according to study design, stent type, assay type, ancestry, presentation diagnosis, and data type. Important findings identified by the subgroup analysis were the significant differences in CRP levels between ISR and no-ISR, amongst Middle Easterners (Nst= 10, SMD 0.63, 95%CI 0.33, 0.93 mg/L, p< 0.0001) and Asians (Nst= 18, SMD 0.71, 95%CI 0.46, 0.96 mg/L, p= 0.00001), however not amongst Europeans (Nst= 9, SMD -0.11, 95%CI -0.43, 0.21 mg/L, p= 0.50). Results obtained for other subgroups however remained consistent and showed significant positive associations. (Figure 2.) Conclusions The present systematic review and meta-analysis indicates a positive association of higher baseline CRP values with the incidence of angiographically confirmed ISR. In subgroup analysis there was no evidence of association amongst Europeans, in contrast to significant associations seen amongst rest of the ancestries. These results warrant further validation in dedicated large cohorts, ideally in a prospective setting.Figure 1.Figure 2.

Consensus on the diagnosis and management of patients with type 2 myocardial infarction: an international Delphi study

Abstract Background Type 2 myocardial infarction occurs due to a reduction in myocardial oxygen supply or an increase in demand without evidence of atherosclerotic plaque rupture. It is common representing around 20% of myocardial infarctions (1-4). Outcomes are poor with up to one third alive at five years, with cardiovascular outcomes comparable to type 1 myocardial infarction (1,5,6). Despite this, there are no evidence-based guidelines to guide assessment and management for clinicians. Purpose To gain consensus on the assessment and management of type 2 myocardial infarction from an international group of experts. Methods A systematic review of type 2 myocardial infarction was undertaken to identify the corresponding or senior author of all original research studies. We identified 73 experts from multiple clinical specialties. A three-round international eDelphi study was circulated, with round one consisting of open questioning to generate statements for deductive analysis. Consensus was defined a priori as >70% agreement on a 5-point Likert scale. Statements for which no consensus could be obtained were adapted and recirculated in round three (Figure 1). Results Of the 68 experts contacted there was a 56% (38/68), 54% (37/68) and 72% (49/68) response rate in round one, two and three, respectively. Consensus was achieved on 64% (43/67) of statements. Consensus varied across the following domains i) definition and diagnosis 42% (5/12), ii) risk stratification 75% (3/4), iii) assessment of coronary artery disease and cardiac function 50% (9/18), iv) specialty management 60% (6/10), v) treatment and secondary prevention 100% (9/9) and vi) communication and rehabilitation 79% (11/15). The panel agreed that all patients should undergo echocardiography (mean [SD] 2.08 [1.23]) and CT coronary imaging or a functional test should be performed on those with intermediate probability of future cardiovascular events (mean [SD] 1.81 [0.52]). Over 90% of the panel agreed that both patient and clinician understanding of type 2 myocardial infarction was poor and that further randomised controlled trials are need to direct care. Conclusion There remains uncertainty regarding the current definition of type 2 myocardial infarction and overall patient and clinician understanding was thought to be poor. However, it is generally accepted that the mainstay of management should be on the identification of coronary artery disease and left ventricular impairment with optimisation of therapies with proven benefit. Management should involve an individualised assessment and the multidisciplinary team.

Abstract 19084: The Deadly Squeeze - Coronary Vasospasm Complicated by Myocardial Infarction and Cardiac Arrest

Introduction: Acute coronary syndrome (ACS) typically results from atherosclerotic plaque rupture. However, about 6% of ST elevation Myocardial Infarction (STEMI) patients have no obstructive disease. We present a case of STEMI, diagnosed with coronary vasospasm. Hypothesis: Methods: A 54-year-old female with alcohol abuse, smoking and uncontrolled hypertension presented after an out of hospital ventricular fibrillation cardiac arrest. EKG showed anterolateral ST elevation (STE). Left heart catheterization (LHC) showed moderate to severe multi-vessel disease without a definitive culprit lesion. STE resolved. Heart team approach for revascularization was contemplated. Echocardiogram showed systolic dysfunction with ejection fraction (EF) of 25%. Patient had another cardiac arrest and EKG showed recurrent anterolateral STE. Repeat LHC showed severe vasospasm of Left anterior descending (LAD) artery and diagonal branch, which improved with intracoronary (IC) nitroglycerin. Vasospasm was attributed to smoking and catecholamine excess from alcohol withdrawal. She was started on intravenous nitroglycerin and amlodipine. Her hospital course was complicated by high degree AV block requiring temporary pacer. She was eventually extubated with good neurological recovery and recovered systolic function (EF 60%). She was counselled on smoking and alcohol cessation and discharged home on isosorbide dinitrate and Amlodipine with planned surgical revascularization. Results: Coronary vasospasm (CVS) can occur both in normal and diseased coronaries. Risk factors include smoking, alcohol use and withdrawal, cocaine, mental stress, etc. Vasospasm may present as Prinzmetal’s angina, myocardial infarction, AV block, or fatal arrhythmias. IC nitroglycerine during LHC aids in diagnosis of CVS in setting of ACS. IVUS (Intravascular ultrasound) may help diagnose presence or absence of concomitant atherosclerotic disease. Provocative testing with IC ergonovine and acetylcholine may be considered in non-ACS setting. Conclusions: This case emphasizes the need to have a high index of suspicion for vasospasm to prevent associated complications and establish an accurate diagnosis and guide proper management of this potentially fatal disease.

Abstract 15953: Stressed Into a STEMI

Introduction: Chest pain is the second most common presenting symptom in the emergency department (ED). 5.1% of all presentations with chest pain are acute coronary syndrome (ACS). ACS includes ST-segment elevation myocardial infarction (STEMI), non-ST segment elevation myocardial infarction (NSTEMI), and unstable angina (UA). We present a case of UA that progressed to STEMI after a regadenoson stress test. Case: A 55 years old male with 30 pack-year smoking history presented to the ED with sudden onset, sharp, left-sided chest pain associated with diaphoresis that lasted a few minutes. EKG showed sinus rhythm with premature ventricular complexes without ischemic changes. High sensitivity troponin at 0, 1, and 3 hours were within normal limits. While he was undergoing a radionucleotide stress test, he reported severe chest pain immediately after the regadenoson injection. Bedside telemetry showed ST elevation in inferior leads. EKG was consistent with 1mm ST-elevation in leads II, III, and aVF. He underwent an emergent coronary angiogram which revealed 100% occlusion in the mid-right coronary artery (RCA) and 80% in the second marginal distribution. He received a drug-eluting stent to RCA with the resolution of his chest pain. Discussion: Rupture or erosion of atherosclerotic plaque exposes the underlying thrombogenic core which can lead to occlusion of the coronary artery. A partial occlusion due to an unstable plaque can lead to UA or NSTEMI. STEMI results from complete occlusion of the coronary circulation. In our case, the patient presented with unstable angina however undergoing a stress test triggered him to STEMI. The administration of regadenoson led to coronary vasodilation, resulting in the redistribution of coronary blood flow away from the nearly occluded RCA but what led to plaque rupture at the same time leading to a STEMI is unclear. Conclusions: A regadenson stress test can trigger STEMI in patients with unstable angina however the mechanism is unclear