Atherosclerotic Plaque Instability Research Articles

Bioinformatics Gene Analysis of Potential Biomarkers and Therapeutic Targets for Unstable Atherosclerotic Plaque-Related Stroke.

Atherosclerotic plaque instability is a major cause of ischemic stroke. Researchers must develop novel strategies for the detection and treatment of unstable atherosclerotic plaque (UAP)-related stroke. We aimed to identify potential biomarkers and therapeutic targets of UAP-related stroke. Differentially expressed genes (DEGs) of UAP, ischemic stroke and smoking were identified by microarray analyses from the Gene Expression Omnibus. Gene Ontology (GO) and pathway functional enrichment analyses of DEGs were performed to analyze plaque destabilization and ischemic stroke physiopathology. An integrative analysis of UAP, ischemic stroke and smoking DEGs and functional annotations was performed to identify the underlying physiopathology and hub genes in UAP-related stroke and the relationship with smoking. Online search databases were applied to confirm hub gene biofunctions and their relationships with atherosclerosis and cerebrovascular diseases. Following integrative analysis, 18 co-DEGs of UAP and ischemic stroke, including 17 upregulated and one downregulated, were identified. Inflammation, immunity, extracellular matrix degradation, blood coagulation, apoptosis and nerve degeneration were the primary physiopathological processes in UAP-related stroke. Hub genes included MMP9, ITGAM, CCR1, NCF2 and CD163, among which MMP9 and ITGAM were top 10 genes for both UAP and stroke. Smoking may upregulate MMP9, NCF2, C5AR1 and ANPEP to accelerate plaque destabilization and UAP-related stroke. MMP9, ITGAM, CCR1, NCF2, CD163, hsa-miR-3123 and hsa-miR-144-3p are potential diagnostic and prognostic biomarkers of UAP-related stroke. MMP9 and ITGAM are potential therapeutic targets of UAP-related stroke, which will contribute to the development of novel management strategies.

Validity of ultrasound arterial wall vascularization for assessment of vascular inflammation

Abstract Background Vascular inflammation plays a fundamental role in most vascular diseases including atherosclerosis and vasculitis syndrome, in which arterial wall vascularization (AWV) frequently develops. Visualization of AWV is informative in detecting the vascular inflammation but is challenging. A new ultrasound technique (superb micro-vascular imaging [SMI]) allows the detection of extremely low-velocity flows. We examined an availability of SMI for assessment of the instability of atherosclerotic plaques and the activity of Takayasu arteritis (TA). Methods and results The study consists of two independent and consecutive parts A and B, examined in carotid stenosis (A) and TA (B), respectively. In part A, 12 patients with symptomatic severe carotid stenosis (CS group) scheduled for carotid endarterectomy were enrolled. In six of 12 patients, preoperative ultrasonography with SMI showed intraplaque neovascularization at the plaque shoulder. Postoperatively, histopathology confirmed the neovessels at the corresponding sites of visualized AWV. SMI had a sensitivity of 67%, specificity of 90% for detection of AWV in CS group. In SMI analysis, false positive findings were caused by motion artifact and arterial wall calcification, and a false negative finding is attributed by intraplaque hemorrhage. In part B, 10 patients with TA were enrolled. All patients underwent 18F-FDG-PET/CT, and its vascular uptake were compared with AWV detected by SMI. Bilateral common carotid arteries (CCA), internal carotid arteries and common iliac arteries were examined by SMI. Active vascular 18F-FDG uptake (max SUV >2.1) were found at five sites in three patients, which were not significantly correlated with the prevalence of macaroni sign, increase in C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). Of note, SMI revealed AWV at five sites corresponding to uptake of 18F-FDG, with a sensitivity/specificity of 100% and 98%, positive predictive value 71%, and a negative predictive value 100%. Conclusion SMI enables visualization of AWV at vulnerable plaque in CS patients and at 18F-FDG positive sites in TA patients. SMI has potential as a modality to detect the vascular inflammation. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant-in-Aid for Scientific Research, Japan

Interactive effects of interferon-gamma functional single nucleotid polymorphism (+874 T/A)with cardiovascular risk factors in coronary heart disease and early myocardial infarction risk.

Atherosclerosis is an inflammatory disease characterized by extensive lipid accumulation in the artery wall. Throughout the atherosclerotic process, interferon-gamma (IFN-γ), which is an important pro-inflammatory cytokine, plays a central role in atherosclerotic plaque instability and the occurrence of myocardial infarction (MI). In this study, we aimed to investigate the relationship between IFN-γ +874 T/A (rs2430561) polymorphism and coronary heart disease (CHD) as well as its effects on MI and CHD. Three hundred and ninety patients with CHD (229 with MI, 161 without MI) and 233 healthy controls were screened by the amplification refractory mutation system (ARMS) PCR method for IFN-γ +874 T/A polymorphism. For MI risk, early adult age was important risk factors and the risk was increased with IFN-γ +874 T/A polymorphism. IFN-γ T allele was significantly increased in the CHD patients with age≤45 (p = 0.048) and patients with history of MI (p = 0.007). As IFN-γ is an inflammatory cytokine with an emerging role in the atherosclerotic process, it was suggested that inhibition of IFN-γ activity could be a therapeutic strategy to stabilize human atherosclerotic plaque. Our findings support the association between MI risk and IFN-γ +874 T/A polymorphism in the Turkish population, particularly by increasing the level of IFN-γ in young patients, thereby causing rupture of vulnerable plaques in atherosclerotic lesions. Identification of the IFN-γ +874 T/A gene variants as risk factors for early CHD and MI development may be a practical biomarker to guide the MI risk process and determine the ideal therapeutic approach.

The Role of Matrix Metalloproteinase-9 in Atherosclerotic Plaque Instability.

Matrix metalloproteinase-9 (MMP-9) belongs to the MMP family and has been widely investigated. Excessive MMP-9 expression can enhance extracellular matrix degradation and promote plaque instability. Studies have demonstrated that MMP-9 levels are higher in vulnerable plaques than in stable plaques. Additionally, several human studies have demonstrated that MMP-9 may be a predictor of atherosclerotic plaque instability and a risk factor for future adverse cardiovascular and cerebrovascular events. MMP-9 deficiency or blocking MMP-9 expression can inhibit plaque inflammation and prevent atherosclerotic plaque instability. All of these results suggest that MMP-9 may be a useful predictive biomarker for vulnerable atherosclerotic plaques, as well as a therapeutic target for preventing atherosclerotic plaque instability. In this review, we describe the structure, function, and regulation of MMP-9. We also discuss the role of MMP-9 in predicting and preventing atherosclerotic plaque instability.

Criteria for Carotid Atherosclerotic Plaque Instability

The study aim is to determine the criteria for carotid atherosclerotic plaque instability with the use of an advanced ultrasound technology, immunohistochemical analysis, and electron paramagnetic resonance (EPR) and assess their correlations with histologic results. A total of 92 patients were included in the study and were examined by ultrasound duplex scanning and ultrasound elastography. Plaques harvested during carotid endarterectomy were obtained for histologic analysis, immunofluorescent assay, and EPR spectroscopic measurements. Multivariate logistic regression analysis showed that plaques with an area >90mm2 (odds ratio [OR], 4.05; 95% confidence interval [CI], 1.32-13.2; P=0.006), plaque volume index>0.6cm3 (OR, 2.72; 95% CI, 1.05-9.58; P=0.04), and juxtaluminal black area ≥8mm2 (OR, 2.82; 95% CI, 1.22-6. 23; P=0.02) were statistically significant independent predictors of histologically verified unstable plaques. Unstable plaques occurred in 94% of the patients with these indicators. Significant increases in the number of CD68+ and CD36+ cells (inflammatory markers) and CD31+ cells (neovasculogenesis markers) were revealed in unstable plaques by the immunohistochemical assay. EPR data analysis showed that divalent manganese could serve as a marker of plaque instability. Additional ultrasound criteria, verified by histologic studies, significantly increased the information content for identifying patients with unstable plaques, which can be of great importance in stratifying the risk of ischemic stroke, especially in asymptomatic patients. The degree of calcification is not a mandatory criterion for plaque stabilization.

Competência Prognóstica Distinta entre Modelo Clínico e Anatômico em Síndromes Coronarianas Agudas: Comparação por Tipo de Desfecho

ResumoFundamento Eventos isquêmicos recorrentes decorrem de instabilidade de placa aterosclerótica, enquanto morte após um evento isquêmico decorre da gravidade do insulto. A natureza diversa desses tipos de eventos pode fazer com que dados clínicos e anatômicos tenham diferentes capacidades prognósticas a depender do tipo de desfecho.Objetivo Identificar as predileções prognósticas de dados clínicos e dados anatômicos em relação a desfechos coronários fatais e não fatais durante hospitalização de pacientes com síndromes coronarianas agudas (SCA).Métodos Pacientes consecutivamente admitidos por SCA que realizaram coronariografia foram recrutados. O escore SYNTAX foi utilizado como modelo anatômico e o escore GRACE como modelo clínico. A capacidade preditora desses escores foi comparada quando à predição de desfechos isquêmicos não fatais (infarto ou angina refratária) e de morte cardiovascular durante hospitalização. Significância estatística foi definida por p < 0,05.Resultados Entre 365 indivíduos, 4,4% foi a incidência de óbito hospitalar e 11% de desfechos isquêmicos não fatais. Para morte cardiovascular, ambos os escores — SYNTAX e GRACE — apresentaram capacidade discriminatória, com estatísticas-C similares: 0,80 (95%IC: 0,70–0,92) e 0,89 (95%IC 0,81–0,96), respectivamente — p=0,19. Quantos aos desfechos isquêmicos não fatais, o escore SYNTAX apresentou valor preditor (estatística-C = 0,64; 95%IC 0,55–0,73), porém o escore GRACE não mostrou associação com esse tipo de desfecho (estatística-C = 0,50; 95%IC: 0,40–0,61) — p=0,027.Conclusão Os modelos clínico e anatômico predizem satisfatoriamente morte cardiovascular em SCA, enquanto a recorrência de instabilidade coronária é melhor prevista por características anatômicas do que por dados clínicos. (Arq Bras Cardiol. 2020; 115(2):219-225)

Associations of iron status with apolipoproteins and lipid ratios: a cross-sectional study from the China Health and Nutrition Survey

BackgroundIron overload has been found to be related with various cardiometabolic disorders, like dyslipidemia, metabolic syndrome, and diabetes. The disturbance of the iron status and lipid metabolism can contribute to organ damage such as atherosclerotic plaque growth and instability. An assessment on the associations of iron status with apolipoproteins and lipid ratios would be informative for maintenance of metabolic homeostasis and hinderance of disease progression. Hence, this study aims to establish the relationships of iron status with apolipoproteins and lipid ratios.MethodsA cross-sectional study of 7540 adult participants from the China Health and Nutrition Survey 2009 was conducted. Logistic regression analyses were used to investigate the relationships between indicators of iron status and the prevalence of unfavorable apolipoprotein profiles. Multivariate linear regression models were constructed to assess the dose-response correlations between serum ferritin and lipid parameters.ResultsAfter adjustment for confounding factors, in both sexes, the subjects in the top quartile of ferritin had the highest prevalence of an elevated apolipoprotein B (men: odds ratio (OR) 1.97, 95% confidence interval (CI) 1.50–2.62; women: OR 2.13, 95% CI 1.53–2.97) and an elevated apolipoprotein B/apolipoprotein A1 ratio (men: OR 2.00, 95% CI 1.50–2.66; women: OR 1.41, 95% CI 1.04–1.92) when compared with individuals in the lowest quartile. Hemoglobin were also independently associated with unfavorable apolipoprotein B and apolipoprotein B/apolipoprotein A1 ratio both in men and women. However, transferrin (men: OR 0.74, 95% CI 0.56–0.99; women: OR 0.73, 95% CI 0.56–0.95) and soluble transferrin receptor (men: OR 0.75, 95% CI 0.57–0.99; women: OR 0.71, 95% CI 0.55–0.91) were found to be negatively associated with a decreased apolipoprotein A1. Moreover, after controlling for potential confounders, the ferritin concentrations were significantly associated with the levels of lipid ratios including TG/HDL-C, non-HDL-C/HDL-C, TC/HDL-C, apoB/apoA1, and LDL-C/HDL-C ratio in men (β coefficient = 0.147, 0.061, 0.043, 0.038, 0.032, respectively, all P values < 0.001) and in women (β coefficient = 0.074, 0.034, 0.025, 0.020, 0.018, respectively, all P values < 0.05).ConclusionsThe indicators of iron status are significantly associated with unfavorable apolipoprotein profiles. Serum ferritin concentrations are positively correlated with the levels of lipid ratios. The management on the modifiable iron status and lipid metabolism has a clinical significance. The atherosclerotic lipid profiles of the patients with iron overload deserve special clinical concerns.

Matrix Metalloproteinases as Biomarkers of Atherosclerotic Plaque Instability.

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases responsible for tissue remodeling and degradation of extracellular matrix (ECM) proteins. MMPs may modulate various cellular and signaling pathways in atherosclerosis responsible for progression and rupture of atherosclerotic plaques. The effect of MMPs polymorphisms and the expression of MMPs in both the atherosclerotic plaque and plasma was shown. They are independent predictors of atherosclerotic plaque instability in stable coronary heart disease (CHD) patients. Increased levels of MMPs in patients with advanced cardiovascular disease (CAD) and acute coronary syndrome (ACS) was associated with future risk of cardiovascular events. These data confirm that MMPs may be biomarkers in plaque instability as they target in potential drug therapies for atherosclerosis. They provide important prognostic information, independent of traditional risk factors, and may turn out to be useful in improving risk stratification.

Role of Interleukin-18 and the Thrombus Precursor Protein in Coronary Artery Disease.

Background Coronary failure is the leading cause of death worldwide and identifying patients at higher risk for coronary artery disease (CAD) is a challenge. Objectives To test the biomarkers interleukin 18 (IL-18) and thrombus precursor protein (TpP), involved in atherogenesis, to aid in the early assessment of CAD. Methods This was a cross-sectional cohort of 119 patients, stratified into three groups: Group I - acute coronary syndrome (39); Group II - chronic CAD (40) and Group III - control, without coronary lesion, but who might have risk factors for CAD (40). Statistical analysis was performed using the statistical program SPSS (Statistical Package for the Social Sciences) for Windows ,version 17.0 of 2008. The significance level was set at 0.05 or 5% (p <0.05), with a 95% confidence interval. Chi-square test (χ2), Analysis of variance (ANOVA), and Tukey's test were used. Results The mean age was 60.36 ± 9.64 years; there was a prevalence of females in Group III (65.0% p = 0.002), but without statistical significance for the means of IL-18 and TpP. The means of IL-18 and TpP were increased in Group I when compared to the other groups; IL-18 = 1325.44 ± 1860.13 ng/dL, p = 0.002; TpP = 35.86 ± 28.36 µg / mL, p <0.001). When compared two-by-two, it was observed that Group I had higher mean IL-18 and TpP values than Group II (IL-18 = 353.81 ± 273.65 ng / dL; TpP = 25.66 ± 12, 17 µg / mL) and Group III (IL-18 = 633.25 ± 993.93 ng / dL; TpP = 18.00 ± 8.45 µg / mL). Conclusion There was an increase in these biomarkers in acute CAD, suggesting a relationship with the atherosclerotic plaque instability process, but not with the chronic phase. (Arq Bras Cardiol. 2020; 114(4):692-698).

The Role of Interleukin-18 in the Development and Progression of Atherosclerosis.

Atherosclerosis (AS), as a chronic inflammatory disorder of the cardiovascular system, is one of the leading causes of ischemic heart disease, stroke and peripheral vascular disease. There is growing evidence on the role of innate and adaptive immunity in the pathogenesis of atherosclerosis. Interleukin-18 is one of the novel proinflammatory cytokines involved in atherogenesis, atherosclerotic plaque instability and plaque rupture. In this review, we overview the findings of preclinical and clinical studies about the role and mechanism of action of IL-18 in the pathogenesis of AS, which could offer novel prognostic and therapeutic approaches.

MiR-155 inhibits oxidized low-density lipoprotein-induced apoptosis in different cell models by targeting the p85α/AKT pathway.

The apoptosis of vascular endothelial cells (VECs), vascular smooth muscle cells (VSMCs), and macrophages directly causes the instability or rupture of atherosclerotic plaques. Accumulating evidence suggests that oxidized low-density lipoprotein (OxLDL) could induce apoptosis via endogenous or exogenous pathways. Interestingly, it has been reported that microRNA155 (miR-155) plays a pivotal role in the regulation of apoptosis. Here, we hypothesized that overexpression of miR-155 could inhibit OxLDL-induced apoptosis by targeting the p85α/AKT pathway. In this study, we established models of OxLDL-induced apoptosis in mouse VECs, VSMCs, and macrophages. Furthermore, we explored the effects of miR-155 expression on the apoptosis of different cells, and ultimately revealed whether miR-155 regulated apoptosis by targeting the p85α/AKT pathway. The results demonstrated that miR-155 inhibited p85α expression and attenuated VEC, VSMC, and macrophage apoptosis, at least in part by suppressing the expression of p85α-activated AKT to inhibit apoptosis. Our findings collectively suggested that miR-155 attenuated OxLDL-mediated apoptosis in different cells by targeting p85α, supporting its possible therapeutic role in atherosclerosis.

β-Endorphin Mediates the Development and Instability of Atherosclerotic Plaques.

β-Endorphin, an endogenous opioid peptide, and its μ-opioid receptor are expressed in brain, liver, and peripheral tissues. β-Endorphin induces endothelial dysfunction and is related to insulin resistance. We clarified the effects of β-endorphin on atherosclerosis. We assessed the effects of β-endorphin on the inflammatory response and monocyte adhesion in human umbilical vein endothelial cells (HUVECs), foam cell formation, and the inflammatory phenotype in THP-1 monocyte-derived macrophages, and migration and proliferation of human aortic smooth muscle cells (HASMCs) in vitro. We also assessed the effects of β-endorphin on aortic lesions in Apoe−/− mice in vivo. The μ-opioid receptor (OPRM1) was expressed in THP-1 monocytes, macrophages, HASMCs, HUVECs, and human aortic endothelial cells. β-Endorphin significantly increased THP-1 monocyte adhesion to HUVECs and induced upregulation of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin via nuclear factor-κB (NF-κB) and p38 phosphorylation in HUVECs. β-Endorphin significantly increased HUVEC proliferation and enhanced oxidized low-density lipoprotein-induced foam cell formation in macrophages. β-Endorphin also significantly shifted the macrophage phenotype to proinflammatory M1 rather than anti-inflammatory M2 via NF-κB phosphorylation during monocyte-macrophage differentiation and increased migration and apoptosis in association with c-jun-N-terminal kinase, p38, and NF-κB phosphorylation in HASMCs. Chronic β-endorphin infusion into Apoe−/− mice significantly aggravated the development of aortic atherosclerotic lesions, with an increase in vascular inflammation and the intraplaque macrophage/smooth muscle cell ratio, an index of plaque instability. Our study provides the first evidence that β-endorphin contributes to the acceleration of the progression and instability of atheromatous plaques. Thus, μ-opioid receptor antagonists may be useful for the prevention and treatment of atherosclerosis.

XANTHINE OXIDASE EXPRESSION IN ATHEROSCLEROTIC CAROTID PLAQUE IS ASSOCIATED WITH PLAQUE VULNERABILITY AND EXPRESSION OF CD163

Xanthine oxidase (XO) expression in macrophages has been linked to pathogenesis of atherosclerosis. Recent studies have revealed that macrophages with increased expression of hemoglobin-haptoglobin receptor CD163 promote atherosclerotic plaque instability. We hypothesized that enhanced XO expression

Serum complement C1q level is associated with acute coronary syndrome

Background and objectivesThe complement system plays an important role in the development of acute coronary syndrome (ACS). Complement C1q is an important initial component of the classical complement pathway and closely related to many chronic inflammatory diseases, including atherosclerosis (AS). We aimed to determine whether there was association between serum complement C1q and the severity of coronary stenosis. Subjects and methods320 patients who underwent coronary arteriography (CAG) were stratified into non-ACS group (control group, n = 74), unstable angina group (UA group, n = 197) and acute myocardial infarction group (AMI group, n = 49) according to the severity of coronary stenosis and clinical manifestations. The severity of coronary stenosis was represented in Gensini score, and serum complement C1q level was compared using immunity transmission turbidity among three groups. ResultsThe level of complement C1q in AMI group was lower significantly than control group and UA group (P < 0.05), but there was no correlation between serum complement C1q and Gensini score (β=-0.086, P = 0.125). In nitrate-taking patients, serum complement C1q had a negative association with Gensini score (r=-0.275, P = 0.001), and in non-smokers, there was also a negative correlation (β=-0.159, P = 0.036). After calibrating smoking, drinking or statins, the serum complement C1q levels of control group, UA group and AMI group decreased in sequence (P < 0.05). Logistic regression analysis showed that the decreasing of serum complement C1q was an unfavorable factor for acute myocardial infarction (OR=0.984, 95 %CI=0.972∼0.997, P = 0.015) and for ACS (OR=0.984, 95 %CI=0.971∼0.984, P = 0.025) in drinking patients. Regrettably, ROC curve suggested that the accuracy in diagnosing coronary atherosclerotic heart disease by serum complement C1q was low (AUC=0.568, 95 %CI= 0.492-0.644, P = 0.076, sensitivity 73.6 %, specificity 58.1 %). ConclusionSerum complement C1q in ACS patients, in particular AMI patients, showed lower level. This finding suggests further decrease of complement C1q level in ACS patients may be a contributory factor to instability or rupture of atherosclerotic plaques. Combined with other clinical indicators, it can be helpful to predict the risk and severity of coronary stenosis.

Immunoproteasome subunit β5i regulates diet-induced atherosclerosis through altering MERTK-mediated efferocytosis in Apoe knockout mice.

The immunoproteasome contains three catalytic subunits (β1i, β2i and β5i) that are important modulators of immune cell homeostasis. A previous study showed a correlation between β5i and human atherosclerotic plaque instability; however, the causative role of β5i in atherosclerosis and the underlying mechanisms remain unknown. Here we explored this issue in apolipoprotein E (Apoe) knockout (eKO) mice with genetic deletion or pharmacological inhibition of β5i. We found that β5i expression was upregulated in lesional macrophages after an atherogenic diet (ATD). β5i/Apoe double KO (dKO) mice fed on the ATD had a significant decrease in both lesion area and necrotic core area, compared with eKO controls. Moreover, dKO mice had less caspase-3+ apoptotic cell accumulation but enhanced efferocytosis of apoptotic cells and increased expression of Mer receptor tyrosine kinase (MERTK). Consistently, similar phenotypes were observed in eKO mice transplanted with dKO bone marrow or treated with β5i-specific inhibitor PR-957. Mechanistic studies in vitro revealed that β5i deletion reduced IκBα degradation and inhibited NF-κB activation, promoting Mertk transcription and efferocytosis, thereby attenuating apoptotic cell accumulation. In conclusion, we demonstrate that β5i plays an important role in diet-induced atherosclerosis by altering MERTK-mediated efferocytosis. β5i might be a potential pharmaceutical target against atherosclerosis. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

P977 CT phenotype of high-risk atherosclerotic plaques causing an acute coronary syndrome compared to silent vulnerable plaques

Abstract Funding Acknowledgements PlaqueImage.- research grant no. 103544/2016, contract number 26/01.09.2016 - Background Previous studies demonstrated that plaque morphology has a crucial role in the development of an acute coronary syndrome (ACS). However, not all vulnerable coronary plaques produce an ACS and the prediction power of various vulnerability features to predict an acute coronary event in a close future, has not been elucidated so far. Objective We aimed to use multi-slice computed tomography angiography (CTA) for assessment of morphological characteristics of culprit lesions producing an ACS in the next several months after CT assessment, in comparison with morphological characteristics of unstable coronary atherosclerotic plaques which did not trigger an ACS. Material and methods We analyzed 40 patients in whom CTA revealed presence of unstable coronary lesions, exhibiting at least one marker of vulnerability: napkin ring sign (NRS), spotty calcium (SC), positive remodeling (PR) or presence of low attenuation plaque (LAP), divided in 2 groups: group 1 - 20 patients who developed an ACS in the next 6 months following CTA examination, and group 2 – 20 patients matched for age, gender and risk factors, who did not present any cardiovascular event 6 month after CTA assessment. Post-processing of multi-slice CTA images was performed in order to assess morphological characteristics and CT-derived markers of atherosclerotic plaque instability. Results Similar mean values of plaque length (17.1 +/- 5.9 mm vs 16.9 +/- 3.4 mm; p = 0.6) and total atheroma volume (188.1 +/- 104.7 mm3vs 186.4 +/- 90.7 mm3; p = 0.8) were obtained for both groups. The mean number of vulnerability markers was 1.6 in group 1 vs 1.2 in group 2 (p = 0.07). However, atherosclerotic lesions in patients from group 1 presented significantly higher values of lipid-rich atheroma (9.8 +/- 10.8 mm3vs 2.6 +/- 1.0 mm3; p = 0.01) and remodeling index (1.14 +/- 0.3 in group 1 vs 0.89 +/- 0.19 in group 2, p = 0.04). At the same time, atheromatous plaques in patients who developed an ACS during the 6-months follow-up showed in a significantly higher proportion LAP (45% in group vs 10% in group 2, p = 0.03) and PR (15%in group 1 versus 5% in group 2, p = 0.04), but not NRS (30% vs 25%, p = ns) or SC (65% vs 40%, p = 0.2). Conclusions Atherosclerotic plaques producing an ACS exhibit a different phenotype than unstable plaques that remain silent. The CTA profile of atheromatous plaques producing an ACS includes the presence of low attenuation, positive remodeling, higher RI and lipid-rich atheroma. Presence of these features in high-risk coronary plaques identifies very high risk patients, who can benefit from adapted therapeutic strategy in order to prevent the development of an ACS.

Ultrasound signs of atherosclerotic plaques destabilization in carotid arteries

Aim. To assess the ultrasonography role for diagnosis of atherosclerotic lesions of the extracranial carotid arteries.Material and methods. The study was conducted on the basis of the St. Petersburg Mariinsky Hospital. A total of 855 patients who were admitted to the regional vascular center due to ischemic stroke or transient ischemic attack were examined. The mean age of the patients was 68 years (min 18, max 107). All patients underwent ultrasound of the carotid arteries.Results. In 570 (66,6%) patients with neurological symptoms (according to clinical and neurological examination), hemodynamically insignificant carotid artery lumen stenosis up to 70-75% was revealed. Ultrasound imaging in all patients revealed signs of atherosclerotic plaque (ASP) instability in various combinations, except for hemorrhage. It was not possible to clearly visualize the finished hemorrhage in the ASP structure.Conclusion. Despite the high informative value of ultrasound, it is not possible to answer all clinical questions with its single use. At the moment, there is no classification of instability signs, reflecting the ASP embolism risk. It needs for paternal change the management of asymptomatic patients. More detailed study of ASP destabilization using various visualization methods is necessary.

Effects of Physical Activity and Sedentary Behavior on Histological Risk Factors of Carotid Atherosclerotic Plaque Instability

Introduction - Carotid atherosclerosis plaque instability is increased by intraplaque hemorrhage (IPH) neovascularization and inflammation (1). Oxidative stress is known to promote these three risk factors and induce a vicious circle with IPH and neovascularization (2). Moreover, it was shown that regular physical activity can reduce oxidative stress by increasing antioxidant defenses whereas sedentary behavior can increase oxidative stress independently to physical activity (3, 4). The aim of this study was therefore to evaluate the effects of both physical activity and sedentary behavior on the carotid plaque histological characteristics and oxidative stress in patients at high-risk of stroke.

P4610Gut microbiome and atherosclerotic plaque instability: does choline consumption in red meat influence plaque stability?

Abstract Background Myocardial infarction is the major cause of deaths worldwide. Gut bacteria can process choline as abundant in red meat and subsequently converted by flavin containing monooxygenase in the liver to trimethylamin-N-oxide (TMAO) metabolite, which is strongly associated with cardiovascular events. Aim To investigate the gut microbiome and its association with atherosclerotic plaque instability. Methods Forty-eight Apolipoprotein E deficient mice were randomly divided into two groups and two time points, fed with a high fat diet (containing either 0.4% choline or 3% choline) at 12 weeks of age, for 7 weeks or for 14 weeks. All mice underwent Tandem Stenosis (TS) surgery to induce the development of unstable plaques. Stool samples were collected directly from the colon. Measurements of gut microbes were performed by AGRF diversity profiling. After bacterial genomic DNA isolation, 16S rRNA were sequenced by targeting 27F-519R (V1-V3) and 341F-806R (V3-V4) on the Illumina MiSeq platform. Vessel segments of TS were histologically processed and plaque composition of lipid, collagen, and intraplaque hemorrhage (marker of unstable plaques) were performed by a series of chemical staining and immunohistochemistry. Results Monocytes and granulocytes in mouse blood were significantly increased in the high choline group (p&lt;0.05, unpaired t-test) after 7 weeks of high fat diet (21% fat, 0.15% Cholesterol, 3% Choline). Profiling of gut microbiota showed that Fimicutes were down regulated in the high choline group (p&lt;0.05, unpaired t-test). Within Phylum Fimicutes, only Clostridia (class) Clostridiales (order) were significantly downregulated. Interestingly, histological analysis of TS segments showed that TER-119 (intraplaque haemorrhage marker) and CD42c (platelet marker) were significantly increased in the high choline group, indicating atherosclerotic plaques are more unstable and prone to rupture (p&lt;0.05, unpaired t-test). Nevertheless, CD68 (Foam cells) in plaques, and total atherosclerotic plaque burden in the aortic sinus and aortic arch were not affected by the elevated levels of choline consumption. Conclusion Choline intake increases circulating monocytes and granulocyte numbers in the blood but not in the atherosclerotic plaque itself. Whereas the total plaque burden is not changed by an increased choline intake, the reduction of Fimicutes, Clostridia and Clostridiales seems to contribute to atherosclerotic plaque instability. Acknowledgement/Funding Heart Foundation 2018 Future Leader Fellowship (2018 FLF) ID: 102068 Chen

P711Histamine promotes atherosclerotic plaque instability via STAT6-dependent macrophage pyroptosis

Abstract Background Atherosclerotic plaque formation and rupture is the primary cause for cardiovascular diseases. It's known that cell death and inflammation are crucial processes leading to atherosclerosis, which involves an important role of histamine. The aim of the present study is to determine the function of signal transducer and activator of transcription 6 (STAT6) in histamine-induced macrophage pyroptosis and plaque instability. Methods We constructed APOE/STAT6 double knock out (DKO) mice via hybridization of ApoE−/− and STAT6−/− mice. 20 ApoE−/− mice (control) and 20 DKO mice were challenged with high-fat diet for 12 weeks while 10 in each group were intraperitoneally infused with histamine (400ug/kg) every other day. The extent and instability of atherosclerotic plaque were determined by oil-red staining, HE staining, immunofluorescence staining and electron microscopy. Changes in subsets of immune cells were evaluated by flow cytometry. Plasma cytokines were assessed by ELISA. Microarray analysis was applied to detect gene expressions while Western blot and real-time PCR was used to assess gene expression levels. Results Morphology studies revealed that histamine could promote plaque formation and vulnerability in ApoE−/− mice, whereas this effect was inhibited in DKO mice. FACS data showed that histamine injection could increase CD11b+Ly6Chigh M1 macrophages differentiation and pyroptosis and facilitate foam cells formation in ApoE−/− mice, which was also inhibited in DKO mice. Microarray analysis and in vitro studies exhibited that histamine could induce the up-regulation of pyrotosis-related proteins such as NLRP3, caspase-1 and MMPs via a STAT6-dependent pathway to promote macrophage pyroptosis and foam cell formation. Conclusions We have characterized a novel role for histamine in modulating atherosclerotic lesion development and progression. Moreover, our work have figured out the detailed mechanisms by which histamine modulates the pyroptosis of macrophages and the progress of unstable atherosclerotic plaques. We envision that this study may provide several potential therapeutic targets benefit for atherosclerosis treatment.