Vulnerable Atherosclerotic Plaques Research Articles

Advances in Noninvasive Carotid Wall Imaging with Ultrasound: A Narrative Review.

Carotid atherosclerosis is a major cause for stroke, with significant associated disease burden morbidity and mortality in Western societies. Diagnosis, grading and follow-up of carotid atherosclerotic disease relies on imaging, specifically ultrasound (US) as the initial modality of choice. Traditionally, the degree of carotid lumen stenosis was considered the sole risk factor to predict brain ischemia. However, modern research has shown that a variety of other imaging biomarkers, such as plaque echogenicity, surface morphology, intraplaque neovascularization and vasa vasorum contribute to the risk for rupture of carotid atheromas with subsequent cerebrovascular events. Furthermore, the majority of embolic strokes of undetermined origin are probably arteriogenic and are associated with nonstenosing atheromas. Therefore, a state-of-the-art US scan of the carotid arteries should take advantage of recent technical developments and should provide detailed information about potential thrombogenic (/) and emboligenic arterial wall features. This manuscript reviews recent advances in ultrasonographic assessment of vulnerable carotid atherosclerotic plaques and highlights the fields of future development in multiparametric arterial wall imaging, in an attempt to convey the most important take-home messages for clinicians performing carotid ultrasound.

Overview on hydrogen sulfide-mediated suppression of vascular calcification and hemoglobin/heme-mediated vascular damage in atherosclerosis

Vulnerable atherosclerotic plaques with hemorrhage considerably contribute to cardiovascular morbidity and mortality. Calcification is the main characteristic of advanced atherosclerotic lesions and calcified aortic valve disease (CAVD). Lyses of red blood cells and hemoglobin (Hb) release occur in human hemorrhagic complicated lesions. During the interaction of cell-free Hb with plaque constituents, Hb is oxidized to ferric and ferryl states accompanied by oxidative changes of the globin moieties and heme release. Accumulation of both ferryl-Hb and metHb has been observed in atherosclerotic plaques. The oxidation hotspots in the globin chain are the cysteine and tyrosine amino acids associated with the generation of Hb dimers, tetramers and polymers. Moreover, fragmentation of Hb occurs leading to the formation of globin-derived peptides. A series of these pro-atherogenic cellular responses can be suppressed by hydrogen sulfide (H2S). Since H2S has been explored to exhibit a wide range of physiologic functions to maintain vascular homeostasis, it is not surprising that H2S may play beneficial effects in the progression of atherosclerosis. In the present review, we summarize the findings about the effects of H2S on atherosclerosis and CAVD with a special emphasis on the oxidation of Hb/heme in atherosclerotic plaque development and vascular calcification.

The effect of plaque morphology, material composition and microcalcifications on the risk of cap rupture: A structural analysis of vulnerable atherosclerotic plaques.

BackgroundThe mechanical rupture of an atheroma cap may initiate a thrombus formation, followed by an acute coronary event and death. Several morphology and tissue composition factors have been identified to play a role on the mechanical stability of an atheroma, including cap thickness, lipid core stiffness, remodeling index, and blood pressure. More recently, the presence of microcalcifications (μCalcs) in the atheroma cap has been demonstrated, but their combined effect with other vulnerability factors has not been fully investigated.Materials and methodsWe performed numerical simulations on 3D idealized lesions and a microCT-derived human coronary atheroma, to quantitatively analyze the atheroma cap rupture. From the predicted cap stresses, we defined a biomechanics-based vulnerability index (VI) to classify the impact of each risk factor on plaque stability, and developed a predictive model based on their synergistic effect.ResultsPlaques with low remodeling index and soft lipid cores exhibit higher VI and can shift the location of maximal wall stresses. The VI exponentially rises as the cap becomes thinner, while the presence of a μCalc causes an additional 2.5-fold increase in vulnerability for a spherical inclusion. The human coronary atheroma model had a stable phenotype, but it was transformed into a vulnerable plaque after introducing a single spherical μCalc in its cap. Overall, cap thickness and μCalcs are the two most influential factors of mechanical rupture risk.ConclusionsOur findings provide supporting evidence that high risk lesions are non-obstructive plaques with softer (lipid-rich) cores and a thin cap with μCalcs. However, stable plaques may still rupture in the presence of μCalcs.

Radiofrequency thermal balloon angioplasty of vulnerable atherosclerotic plaque accompanied by delta-aminolevulinic acid photodynamic therapy and catheter-based samarium-153 brachytherapy

Abstract Background The balloon angioplasty methods that are currently in use, cause to inflammation and subsequent neoatherosclerosis. Purpose The aim of this study was to evaluate the effect of combined photodynamic therapy and brachytherapy on inflammation and intimal hyperplasia reduction after radiofrequency thermal balloon angioplasty of carotid artery in an animal model of thin fibrous cap atheromatous plaque, wherein a high resolution diagnostic ultrasound is adjuncted with angioplasty and combination therapy system, with a goal of increased safety. Methods Briefly, New Zealand white rabbits were submitted to carotid artery vulnerable atherosclerotic plaque by primary intravascular balloon injury followed by a 1.5% cholesterol-rich diet for eight weeks. Histopathology results showed the formation of advanced atherosclerosis with a foam cell-rich atheromatous plaque, resulted in severe stenosis (>70%) in all of the rabbits' arteries. Then treatment group underwent B-mode ultrasound-guided radiofrequency thermal balloon angioplasty followed by catheter-based samarium-153 brachytherapy (153Sm, 18 Gy, β particles) and photosensitizer delta-aminolevulinic acid (delta-ALA)-mediated fiber optic catheter-based polarized light-emitting diodes (LEDs) violet light (λ±Δλ = 405±5 nm, E/A = 120 J/cm2) photodynamic therapy. Results Results from ultrasonography and histopathology showed a significant reduction in the mean value for macrophages, lymphocytes, mast cells, foam cells and hyperplastic vascular smooth muscle cells density after angioplasty in the treatment group compared with the other groups (p<0.05). Conclusion Apoptotic effect of brachytherapy in combination with cytotoxic and anti-inflammatory effect of delta-ALA photodynamic therapy on immune cells and hyperplastic vascular smooth muscle cells, can cause to reduce the neoatherosclerosis in the intimal layer. These findings provide the basis for developing of combined brachytherapy and photodynamic therapy for a successful clinical application in the inhibition of neoatherosclerosis after radiofrequency thermal balloon angioplasty. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Mehrad Research Lab

Coronary inflammation by computed tomography pericoronary fat attenuation in young male anabolic androgenic steroid users

Abstract Background The illicit use of anabolic androgenic steroids (AAS) has been associated with diminished cholesterol efflux mediated by HDL, remarkable decrease in high-density lipoprotein (HDL) plasma concentration and subclinical coronary artery disease (CAD). Inflammation is the key to the atherogenic process associated with atherosclerotic plaque vulnerability. The pericoronary mean fat attenuation (pFAM) has emerged as a marker of coronary inflammation and can predict future cardiovascular events, which is measurable from standard coronary computed tomography angiography (CCTA). However, whether AAS abuse has a role in pFAM in young male AAS users is unknown. Purpose The aim of this study was to evaluate whether AAS abuse could leads to higher pFAM and premature coronary inflammation in young male AAS users. Methods Twenty strength-trained AAS users (AASU) age 29±5 yr, 20 age-matched strength-trained AAS nonusers (AASNU), and 10 sedentary controls (SC) were enrolled in this study. Coronary inflammation was assessed by pFAM-CCTA in the right coronary artery (RCA), left anterior descending artery (LDA) and left circumflex coronary artery (Cx). Results pFAM in the RCA was significantly higher in AASU compared with AASNU and SC (−64.59±9.45 vs. −79.21±6.67 vs. −80.97±7,91 Hounsfield Units (HU), respectively, p<0.001]. Also, the pFAM in the LAD was higher in AASU compared with AASNU and SC (−72.83±7.21 vs. −79.41±6.72 vs. −80.97±7.72 HU, p=0.006). However, no difference to pFAM in the Cx between AASU, AASNU and SC (−74.30±5.85 vs. −79.77±7.13 vs. −78.19±5.82 HU, respectively, p=0.069) was found. Conclusion This study indicates that AAS abuse may be associated with higher pFAM and premature coronary inflammation in the RCA and LAD. The higher pFAM may be linked to early development of CAD in young AAS users. Funding Acknowledgement Type of funding sources: Other. Main funding source(s): Fundação Zerbini

Molecular imaging of experimental atherosclerosis using anti-malondialdehyde-modified low-density lipoprotein humanised antibody fragment targeted nanoparticles

Abstract Introduction Oxidative modification of low-density lipoprotein (LDL), for example by malondialdehyde (MDA) adduction with subsequent uptake by macrophages to form foam cells and later the plaque necrotic core, is a key initiating event in atherogenesis. Accordingly, a larger lipid necrotic core is a key plaque vulnerability factor, predisposing plaques to rupture and subsequent thrombosis and development of an acute coronary syndrome. Thus, MDA-LDL is an attractive focus for the molecular targeting of atherosclerotic plaques. Purpose To develop antibody fragment-targeted nanoparticles that can be utilised for both the molecular imaging and therapeutics of vulnerable atherosclerotic plaques. Methods LO1 is an IgG3k natural monoclonal murine antibody that reacts with MDA-LDL. Humanised LO1Fab fragments have been engineered to reduce immunogenicity and improve lesion penetration. These humanised LO1Fab fragments were used to functionalise fluorescent poly(lactic-co-glycolic acid) (PLGA) - polyethylene glycol (PEG) nanoparticles. Nanoparticle in vitro function was assessed, prior to fluorescence molecular tomography (FMT) co-registered with micro-CT, four-hours after iv injection in atherosclerotic LDL-receptor−/− mice fed a high-fat diet for 40-weeks. Results Humanised LO1Fab fragment conjugated fluorescent PLGA-PEG nanoparticles were formulated with 210nm size and polydispersity index (variability of nanoparticle size around the average) of <0.2. Antibody conjugation efficiency was 30%. In vitro function was confirmed on ELISA versus the blank untargeted nanoparticles with MDA-LDL on solid phase, detecting nanoparticle presence via the conjugated LO1Fab, PEG corona or fluorescence. Fluorescence microscopy on stained aortic root cryosections from atherosclerotic mice confirmed binding to fatty lesions. Construct in vivo in half-life was 90-minutes for both the targeted and untargeted nanoparticles in a two-phase model in LDL-receptor−/− mice, based on fluorescence analysis of serial tail vein blood samples. There was greater uptake in the region-of-interest (heart and aortic arch vessels) in mice injected with LO1Fab-conjugated nanoparticles versus untargeted nanoparticles (mean ± standard deviation) (64.7±22.9 versus 25.2±26.5pmol of Cy5; n=7; p=0.02). Ex vivo analysis fluorescence reflectance imaging and quantitative FMT of the extracted aortae confirmed these findings (1.0±0.3 versus 0.5±0.2pmol of Cy5; n=7; p=0.002; Figure 1). Conclusions Humanised antibody Fab fragment fluorescent nanoparticles have been developed that successfully target MDA-LDL and localise to atherosclerotic plaques in murine experimental atherosclerosis. These targeted nanoparticles have the potential to amplify fluorescent signal for imaging and carry a therapeutic cargo for targeted drug delivery direct to atherosclerotic plaques. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Wellcome Trust Clinical Research Fellowship

Association between plasma desmosine, a marker of elastin degradation, and total atherosclerotic burden measured by whole body magnetic resonance angiography

Abstract Background Elastin degradation has been implicated in the pathophysiology of vulnerable atherosclerotic plaque. Desmosine is the cross-link component in the elastin molecule and is exclusively released from mature elastin breakdown, thus has the potential to be a physiologically relevant biomarker of atherosclerosis. Objectives The aim of the present study was: 1. To investigate whether patients with known cardiovascular disease (CVD) have higher elastin degradation as indicated by plasma desmosine (pDES); 2. to determine the relationship between pDES and total atherosclerotic burden. Methods We measured pDES by a validated stable isotope dilution LC-MS/MS method1 in a total of 146 subjects from the SUMMIT (SUrrogate markers for Micro- and Macro-vascular hard endpoints for Innovative diabetes Tools) study2. (62% male, mean age 64±8 (SD) years). This included 62 patients with prior clinical diagnosis of CVD (including coronary artery disease (CAD), cerebrovascular disease and/or lower extremity arterial disease (LEAD)), and 84 patients without a clinical diagnosis of CVD. Total atherosclerotic burden was measured by whole body magnetic resonance angiography (WB-MRA). The WB-MRA data was divided into 31 anatomical arterial segments with each segment scored according to degree of luminal narrowing: 0 = no stenosis, 1 = <50% stenosis, 2 = 51–70% stenosis, 3 = 71–99% stenosis, 4 = vessel occlusion. The segment scores were summed and from this, a standardized atheroma score (SAS) was calculated by summing each individual segment's stenosis score, and divided by the number of diagnostic segments before dividing by 4 which is the maximum potential score. Relationship between SAS and pDES levels was investigated using multiple linear regression models Results pDES levels were significantly greater in patients with established clinical CVD compared to patients with no CVD (CVD patients, 0.56 (0.45–0.67) ng/mL; patients with no CVD, 0.47 (0.41–0.54)ng/mL; p=0.001). Median SAS for the study population was 4 (2–10). Overall pDES levels showed a strong correlation with SAS (r=0.44, p≤0.001). Univariable analysis suggested a significant association between pDES and whole-body atheroma score as measured by SAS. (β 29.31, p<0.001). This association persisted in the multivariable regression model adjusting for traditional cardiovascular risk factors including age, gender, BMI, systolic blood pressure, diabetes, smoking status and LDL. (adjusted β 18.75, p=0.004) Conclusion pDES levels are elevated in patients with clinical CVD when compared to those with no clinical history of CVD. pDES is also strongly associated with global atheroma burden. Overall, these findings support the role of pDES as a potential biomarker for atherosclerosis. Funding Acknowledgement Type of funding sources: None.

Evolving concepts of the vulnerable atherosclerotic plaque and the vulnerable patient: implications for patient care and future research.

Understanding the natural history of coronary artery atherosclerosis is necessary to determine prognosis and prescribe effective therapies. Traditional management of coronary artery disease has focused on the treatment of flow-limiting anatomical obstructions that lead to ischaemia. In most scenarios, revascularization of these atherosclerotic plaques has not substantially improved freedom from death or myocardial infarction, questioning the utility of contemporary revascularization strategies to improve prognosis. Advances in non-invasive and invasive imaging techniques have helped to identify the characteristics of obstructive and non-obstructive plaques that are precursors for plaque progression and future acute coronary syndromes as well as cardiac death. These 'vulnerable plaques' develop as a consequence of systemic inflammation and are prone to inducing thrombosis. Vulnerable plaques most commonly have a large plaque burden with a well-formed necrotic core and thin fibrous cap and are metabolically active. Perivascular adipose tissue might, in some patients, be used as a surrogate for coronary inflammation and predict future risk of adverse cardiac events. Vulnerable plaques can be identified in their quiescent state, offering the potential for therapeutic passivation. In this Review, we describe the biological and compositional features of vulnerable plaques, the non-invasive and invasive diagnostic modalities to characterize vulnerable plaques, the prognostic utility of identifying vulnerable plaques, and the future studies needed to explore the value of intensified pharmacological and focal treatments of vulnerable plaques.

Estrogen Receptor Subtypes Elicit a Distinct Gene Expression Profile of Endothelial-Derived Factors Implicated in Atherosclerotic Plaque Vulnerability.

In the presence of established atherosclerosis, estrogens are potentially harmful. MMP-2 and MMP-9, their inhibitors (TIMP-2 and TIMP-1), RANK, RANKL, OPG, MCP-1, lysyl oxidase (LOX), PDGF-β, and ADAMTS-4 play critical roles in plaque instability/rupture. We aimed to investigate (i) the effect of estradiol on the expression of the abovementioned molecules in endothelial cells, (ii) which type(s) of estrogen receptors mediate these effects, and (iii) the role of p21 in the estrogen-mediated regulation of the aforementioned factors. Human aortic endothelial cells (HAECs) were cultured with estradiol in the presence or absence of TNF-α. The expression of the aforementioned molecules was assessed by qRT-PCR and ELISA. Zymography was also performed. The experiments were repeated in either ERα- or ERβ-transfected HAECs and after silencing p21. HAECs expressed only the GPR-30 estrogen receptor. Estradiol, at low concentrations, decreased MMP-2 activity by 15-fold, increased LOX expression by 2-fold via GPR-30, and reduced MCP-1 expression by 3.5-fold via ERβ. The overexpression of ERα increased MCP-1 mRNA expression by 2.5-fold. In a low-grade inflammation state, lower concentrations of estradiol induced the mRNA expression of MCP-1 (3.4-fold) and MMP-9 (7.5-fold) and increased the activity of MMP-2 (1.7-fold) via GPR-30. Moreover, p21 silencing resulted in equivocal effects on the expression of the abovementioned molecules. Estradiol induced different effects regarding atherogenic plaque instability through different ERs. The balance of the expression of the various ER subtypes may play an important role in the paradoxical characterization of estrogens as both beneficial and harmful.

3D-Arterial analysis software and CEUS in the assessment of severity and vulnerability of carotid atherosclerotic plaque: a comparison with CTA and histopathology

PurposeOur purpose is to assess Multiparametric Ultrasound (MPUS) efficacy for evaluation of carotid plaque vulnerability and carotid stenosis degree in comparison with Computed Tomography angiography (CTA) and histology.Material and methods3D-Arterial Analysis is a 3D ultrasound software that automatically provides the degree of carotid stenosis and a colorimetric map of carotid plaque vulnerability.We enrolled 106 patients who were candidates for carotid endarterectomy. Prior to undergoing surgery, all carotid artery plaques were evaluated with Color-Doppler-US (CDUS), Contrast-Enhanced Ultrasound (CEUS), and 3D Arterial analysis (3DAA) US along with Computerized Tomographic Angiography (CTA) to assess the carotid artery stenosis degree. Post-surgery, the carotid specimens were fixed with 10% neutral buffered formalin solution, embedded in paraffin and used for light microscopic examination to assess plaque vulnerability morphological features.ResultsThe results of the CTA examinations revealed 91 patients with severe carotid stenoses with a resultant diagnostic accuracy of 82.3% for CDUS, 94.5% for CEUS, 98.4% for 3DAA, respectively. The histopathological examination showed 71 vulnerable plaques with diagnostic accuracy values of 85.8% for CDUS, 93.4% for CEUS, 90.3% for 3DAA, 92% for CTA, respectively.ConclusionsThe combination of CEUS and 3D Arterial Analysis may provide a powerful new clinical tool to identify and stratify “at-risk” patients with atherosclerotic carotid artery disease, identifying vulnerable plaques. These applications may also help in the postoperative assessment of treatment options to manage cardiovascular risks.

Slice-based and time-specific hemodynamic measurements discriminate carotid artery vulnerable atherosclerotic plaques

Background and objectiveHemodynamic patterns play key roles in progression of carotid vulnerable plaques. However, most of previous studies utilized maximum or averaged value of hemodynamic measurements which is not an ideal representative of hemodynamic patterns. This study aimed to investigate the association of slice-based and time-specific hemodynamic measurements with carotid vulnerable plaque using magnetic resonance (MR) vessel wall imaging and histology. MethodsThirty-two patients (mean age: 63.9±8.1 years; 25 males) with carotid atherosclerotic stenosis (≥50% stenosis) referred to carotid endarterectomy were recruited and underwent MR vessel wall imaging. Carotid plaque burden was evaluated on MR images and vulnerable plaque features including calcification, lipid-rich necrotic core, and intra-plaque hemorrhage (IPH) were identified by histology. The slice-based and time-specific hemodynamic measurements were extracted from computational fluid dynamics simulation of 3D carotid arterial model. Correlation coefficients between hemodynamic measurements and carotid plaque features were calculated and the logistic regressions with generalized estimating equation (GEE) were conducted. The value in discriminating carotid vulnerable plaque features was determined by receiver-operating-characteristic analysis. ResultsOf 102 MR-histology matched slices from 32 patients, time-averaged wall shear stress (TAWSS) (r=0.263, p=0.008), oscillatory shear index (OSI) (r=-0.374, p<0.001), and peakWSS (r=0.232, p=0.019) were significantly associated with carotid IPH. The logistic regression with GEE revealed that peakWSS (OR, 1.206; 95% CI, 1.026-1.418; p, 0.023) and TAWSS (OR, 0.364, 95% CI, 0.138-0.959; p, 0.041) were significantly associated with presence of IPH after adjusting for age and BMI. In discriminating carotid IPH, the AUC of TAWSS, OSI, combined TAWSS with maximum wall thickness (MWT) and combined OSI with MWT was 0.656, 0.722, 0.761, and 0.764, respectively. ConclusionsSlice-based and time-specific hemodynamic characteristics could effectively discriminate carotid IPH. Combination of hemodynamic measurements with carotid plaque burden might be a stronger indicator for carotid vulnerable plaque features than each measurement alone.

Associations of the fatty acids with the concentration of antioxidant enzymes in the blood in men with coronary heart disease

Background and Aims : Objective: to identify associations of fatty acids (FAs) with the antioxidant enzymes in the blood of men with coronary heart disease (CHD).Methods: The study included: control group – 20 men without CHD, core group – 60 men with CHD. The core group was divided into subgroups: subgroup I – with the presence of vulnerable atherosclerotic plaques, subgroup II – with the absence of vulnerable atherosclerotic plaques. The levels of FAs, free radicals, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were analyzed in the blood.Results: In patients with CHD, compared with the control group: 1) were higher in the levels of SOD, CAT, myristic, palmitic, palmitoleic and octadecenoic FAs; 2) were lower in the levels of GPx, α-linolenic, docosapentaenoic, docosahexaenoic and arachidonic FAs. In subgroup I were found: 1) negative associations of SOD – with linoleic, eicosatrienoic, arachidonic, eicosapentaenoic, docosapentaenoic and docosahexaenoic FAs, positive associations – with palmitic acid; 2) positive correlations of CAT level with palmitoleic and stearic acids; 3) negative associations between of GPx and palmitic, palmitoleic, stearic and octadecenoic FAs. In subgroup II, the results of the correlation analysis were markedly different.Conclusions: Changes in the levels of antioxidant enzymes, and a disbalance of the FAs profile, probably indicate active oxidative processes in the body and may indicate the presence of atherosclerotic changes in the vessels. The study was conducted within the framework of: budget topic under State Task No. AAAA–A17-117112850280-2, with the support of bioresource collections; financial support from the Government of the Novosibirsk Region. Background and Aims : Objective: to identify associations of fatty acids (FAs) with the antioxidant enzymes in the blood of men with coronary heart disease (CHD). Methods: The study included: control group – 20 men without CHD, core group – 60 men with CHD. The core group was divided into subgroups: subgroup I – with the presence of vulnerable atherosclerotic plaques, subgroup II – with the absence of vulnerable atherosclerotic plaques. The levels of FAs, free radicals, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were analyzed in the blood. Results: In patients with CHD, compared with the control group: 1) were higher in the levels of SOD, CAT, myristic, palmitic, palmitoleic and octadecenoic FAs; 2) were lower in the levels of GPx, α-linolenic, docosapentaenoic, docosahexaenoic and arachidonic FAs. In subgroup I were found: 1) negative associations of SOD – with linoleic, eicosatrienoic, arachidonic, eicosapentaenoic, docosapentaenoic and docosahexaenoic FAs, positive associations – with palmitic acid; 2) positive correlations of CAT level with palmitoleic and stearic acids; 3) negative associations between of GPx and palmitic, palmitoleic, stearic and octadecenoic FAs. In subgroup II, the results of the correlation analysis were markedly different. Conclusions: Changes in the levels of antioxidant enzymes, and a disbalance of the FAs profile, probably indicate active oxidative processes in the body and may indicate the presence of atherosclerotic changes in the vessels. The study was conducted within the framework of: budget topic under State Task No. AAAA–A17-117112850280-2, with the support of bioresource collections; financial support from the Government of the Novosibirsk Region.

Vessel wall MR imaging of aortic arch, cervical carotid and intracranial arteries in patients with embolic stroke of undetermined source: A narrative review.

Despite advancements in multi-modal imaging techniques, a substantial portion of ischemic stroke patients today remain without a diagnosed etiology after conventional workup. Based on existing diagnostic criteria, these ischemic stroke patients are subcategorized into having cryptogenic stroke (CS) or embolic stroke of undetermined source (ESUS). There is growing evidence that in these patients, non-cardiogenic embolic sources, in particular non-stenosing atherosclerotic plaque, may have significant contributory roles in their ischemic strokes. Recent advancements in vessel wall MRI (VW-MRI) have enabled imaging of vessel walls beyond the degree of luminal stenosis, and allows further characterization of atherosclerotic plaque components. Using this imaging technique, we are able to identify potential imaging biomarkers of vulnerable atherosclerotic plaques such as intraplaque hemorrhage, lipid rich necrotic core, and thin or ruptured fibrous caps. This review focuses on the existing evidence on the advantages of utilizing VW-MRI in ischemic stroke patients to identify culprit plaques in key anatomical areas, namely the cervical carotid arteries, intracranial arteries, and the aortic arch. For each anatomical area, the literature on potential imaging biomarkers of vulnerable plaques on VW-MRI as well as the VW-MRI literature in ESUS and CS patients are reviewed. Future directions on further elucidating ESUS and CS by the use of VW-MRI as well as exciting emerging techniques are reviewed.

Impact of Alirocumab on Release Markers of Atherosclerotic Plaque Vulnerability in Patients with Mixed Hyperlipidemia and Vulnerable Atherosclerotic Plaque.

Background and Objectives: Atherosclerosis is a disease in the pathogenesis of which plasma factors apart from elevated cholesterol levels play a keyrole. Such factors include osteopontin (OPN), osteoprotegerin (OPG), and metalloproteinases (MMPs), which are factors that may be responsible for the stabilization of atherosclerotic plaque. The aim of this study was to assess the effect of modern lipid-lowering therapy by using proprotein convertase subtilisin/kexin type 9 (PCSK-9) inhibitor on the concentrations of these factors. Materials and Methods: The study included people suffering from dyslipidemia who were eligible to start alirocumab therapy. In this group, the concentrations of OPN, OPG, and MMPs were assessed before the initiation of therapy and after three months of its duration. Results: In the study, we observed a statistically significant reduction in the concentrations of OPN, OPG (p < 0.001), and metalloproteinase 2 (MMP-2) (p < 0.05) after the applied therapy. Moreover, we noticed that in the group of patients soon to start alirocumab therapy, the concentrations of these factors were higher compared to the control group (p < 0.001). Conclusions: The results of our study show that therapy with alirocumab significantly reduces the concentration of factors that affect atherosclerotic plaque vulnerability, which may explain their important role in reducing cardiovascular risk in patients undergoing this therapy.

Non-Invasive Modalities in the Assessment of Vulnerable Coronary Atherosclerotic Plaques.

Coronary atherosclerosis is a complex, multistep process that may lead to critical complications upon progression, revolving around plaque disruption through either rupture or erosion. Several high-risk features are associated with plaque vulnerability and may add incremental prognostic information. Although invasive imaging modalities such as optical coherence tomography or intravascular ultrasound are considered to be the gold standard in the assessment of vulnerable coronary atherosclerotic plaques (VCAPs), contemporary evidence suggests a potential role for non-invasive methods in this context. Biomarkers associated with deleterious pathophysiologic pathways, including inflammation and extracellular matrix degradation, have been correlated with VCAP characteristics and adverse prognosis. However, coronary computed tomography (CT) angiography has been the most extensively investigated technique, significantly correlating with invasive method-derived VCAP features. The estimation of perivascular fat attenuation as well as radiomic-based approaches represent additional concepts that may add incremental information. Cardiac magnetic resonance imaging (MRI) has also been evaluated in clinical studies, with promising results through the various image sequences that have been tested. As far as nuclear cardiology is concerned, the implementation of positron emission tomography in the VCAP assessment currently faces several limitations with the myocardial uptake of the radiotracer in cases of fluorodeoxyglucose use, as well as with motion correction. Moreover, the search for the ideal radiotracer and the most adequate combination (CT or MRI) is still ongoing. With a look to the future, the possible combination of imaging and circulating inflammatory and extracellular matrix degradation biomarkers in diagnostic and prognostic algorithms may represent the essential next step for the assessment of high-risk individuals.

Increased proteolytic cleavage of osteoglycin is associated with a stable plaque phenotype and lower risk of cardiovascular events

Background and aimsExtracellular matrix (ECM) remodeling is one of the key components in the formation of vulnerable atherosclerotic plaques and cardiovascular events. We recently showed that the full-length ECM-proteoglycan osteoglycin was associated with plaque vulnerability and future cardiovascular events. In the present study, we aimed to investigate the association of cleaved osteoglycin with plaque phenotype. MethodsTwo-hundred human carotid plaques were analyzed by immunohistochemistry. Cleaved osteoglycin and active caspase-3 were assessed by ELISA. ECM components (collagen, elastin and glycosaminoglycans) were assessed by colorimetric assays in plaque tissue homogenates. Matrix metalloproteinases (MMPs) were assessed using Milliplex. MMP-cleavage of osteoglycin and its effect on apoptosis were studied in vitro. Cardiovascular events were recorded during follow-up using national registries. ResultsPlaque levels of cleaved osteoglycin were significantly higher in asymptomatic plaques and correlated to α-actin plaque area, collagen, elastin and inversely to lipids, active.caspase-3 and a histological vulnerability index. Cleaved osteoglycin correlated to several MMPs, especially MMP-12, which was also shown to cleave osteoglycin in vitro. In vitro cleavage of osteoglycin was also associated with less smooth muscle cell apoptosis. Patients with high plaque levels of cleaved osteoglycin had a significantly lower risk to suffer from future cardiovascular events. ConclusionsThe current study shows that cleaved osteoglycin is associated with a stable plaque phenotype and lower risk for future cardiovascular events. Potentially due to reduced cell apoptosis and ability to retain LDL. These results indicate that targeting the cleavage of osteoglycin may be a potential therapeutic strategy to stabilize plaques.

The Profile of Circulating Blood microRNAs in Outpatients with Vulnerable and Stable Atherosclerotic Plaques: Associations with Cardiovascular Risks.

Non-coding RNAs reflect many biological processes in the human body, including athero-sclerosis. In a cardiology outpatient department cohort (N = 83), we aimed to compare the levels of circulating microRNAs in groups with vulnerable plaques (N = 22), stable plaques (N = 23) and plaque-free (N = 17) depending on coronary computed tomography angiography and to evaluate associations of microRNA levels with calculated cardiovascular risks (CVR), based on the SCORE2 (+OP), ACC/AHA, ATP-III and MESA scales. Coronary computed tomography was performed on a 640-slice computed tomography scanner. Relative plasma levels of microRNA were assessed via a real-time polymerase chain reaction. We found significant differences in miR-143-3p levels (p = 0.0046 in plaque-free vs. vulnerable plaque groups) and miR-181b-5p (p = 0.0179 in stable vs. vulnerable plaques groups). Analysis of microRNA associations with CVR did not show significant differences for SCORE2 (+OP) and ATPIII scales. MiR-126-5p and miR-150-5p levels were significantly higher (p < 0.05) in patients with ACC/AHA risk >10% and miR-145-5p had linear relationships with ACC/AHA score (adjusted p = 0.0164). The relative plasma level of miR-195 was higher (p < 0.05) in patients with MESA risk > 7.5% and higher (p < 0.05) in patients with zero coronary calcium index (p = 0.036). A linear relationship with coronary calcium was observed for miR-126-3p (adjusted p = 0.0484). A positive correlation with high coronary calcium levels (> 100 Agatson units) was found for miR-181-5p (p = 0.036). Analyzing the biological pathways of these microRNAs, we suggest that miR-143-3p and miR-181-5p can be potential markers of the atherosclerosis process. Other miRNAs (miR-126-3p, 126-5p, 145-5p, 150-5p, 195-5p) can be considered as potential cardiovascular risk modifiers, but it is necessary to validate our results in a large prospective trial.

Impact of PCSK9 Inhibition on Proinflammatory Cytokines and Matrix Metalloproteinases Release in Patients with Mixed Hyperlipidemia and Vulnerable Atherosclerotic Plaque.

Atherosclerosis is a disorder in which, in addition to high cholesterol levels, several plasma factors play a significant role in its development. Among these cytokines and molecules are interleukin 6 (IL-6), interleukin 18 (IL-18), tumor necrosis factor α (TNF-α), metalloproteinase 2 (MMP-2), and metalloproteinase 9 (MMP-9), all of which may contribute to the stabilization of atherosclerotic plaque. The purpose of this study was to determine the effect of advanced lipid-lowering therapy on the levels of these determinants by utilizing proprotein convertase subtilisin/kexin type 9 (PCSK-9) inhibitors in patients with verified high-risk atherosclerotic plaque. Methods: The study involved patients with dyslipidemia who had the presence of unstable atherosclerotic plaque verified by ultrasonography and who were eligible to begin alirocumab treatment. The levels of IL-6, IL, 18, TNF-α, and MMPs were determined in this group before and after three months of therapy. After treatment, a statistically significant decrease in concentrations of Il-18, Il-6, TNF-α (p < 0.001) and MMP-2 (p < 0.05) was observed. Additionally, we observed that the concentrations of these markers were significantly higher in the group of patients prior to initiating therapy than in the control group. Our study’s results suggest that PCSK-9 inhibitor therapy significantly reduces the concentration of factors influencing the stability of atherosclerotic plaque, which may explain their essential importance in reducing cardiovascular risk in patients receiving this treatment.

Regulation of cardiovascular health and disease by visceral adipose tissue-derived metabolic hormones.

Visceral adipose tissue (VAT) is a metabolic organ known to regulate fat mass, and glucose and nutrient homeostasis. VAT is an active endocrine gland that synthesizes and secretes numerous bioactive mediators called 'adipocytokines/adipokines' into systemic circulation. These adipocytokines act on organs of metabolic importance like the liver and skeletal muscle. Multiple preclinical and in vitro studies showed strong evidence of the roles of adipocytokines in the regulation of metabolic disorders like diabetes, obesity and insulin resistance. Adipocytokines, such as adiponectin and omentin, are anti-inflammatory and have been shown to prevent atherogenesis by increasing nitric oxide (NO) production by the endothelium, suppressing endothelium-derived inflammation and decreasing foam cell formation. By inhibiting differentiation of vascular smooth muscle cells (VSMC) into osteoblasts, adiponectin and omentin prevent vascular calcification. On the other hand, adipocytokines like leptin and resistin induce inflammation and endothelial dysfunction that leads to vasoconstriction. By promoting VSMC migration and proliferation, extracellular matrix degradation and inflammatory polarization of macrophages, leptin and resistin increase the risk of atherosclerotic plaque vulnerability and rupture. Additionally, the plasma concentrations of these adipocytokines alter in ageing, rendering older humans vulnerable to cardiovascular disease. The disturbances in the normal physiological concentrations of these adipocytokines secreted by VAT under pathological conditions impede the normal functions of various organs and affect cardiovascular health. These adipokines could be used for both diagnostic and therapeutic purposes in cardiovascular disease.

Relationship of Microchannels and Plaque Erosion in Patients with ST-Segment Elevation Myocardial Infarction: An Optical Coherence Tomography Study

Abstract Objective: Microchannels are associated with the progression of atherosclerotic vulnerable plaques. However, in patients with culprit optical coherence tomography (OCT)-defined plaque erosion, the knowledge of microchannels and culprit lesion vulnerability is limited. The aim of this study was to investigate culprit lesion characteristics in patients with ST-segment elevated myocardial infarction (STEMI) caused by plaque erosion with and without microchannels using OCT. Methods: In all, 348 STEMI patients with plaque erosion who underwent OCT of the culprit lesion at the 2nd Affiliated Hospital of Harbin Medical University (Harbin, China) from August 2014 to December 2017 were included and divided into the microchannel group (n = 116, 33.3%) and no-microchannel group (n = 232, 66.7%). The clinical characteristics and OCT-derived plaque features were compared between both groups. Results: Among the 348 STEMI patients with plaque erosion, culprit lesions with microchannels had higher incidence of lipid plaque (59.5% vs. 45.3%, P = 0.012); calcification (41.4% vs. 24.6%, P = 0.002); spotty calcification (30.2% vs. 18.1%, P = 0.014); macrophages accumulation (72.4% vs. 45.7%, P &lt; 0.001); and cholesterol crystals (32.8% vs. 14.2%, P &lt; 0.001) than those without microchannels. In addition, minimal lumen area was smaller ((1.9 ± 0.9) mm2 vs. (2.8 ± 2.3) mm2, P &lt; 0.001) and lumen area stenosis was greater ((71.3% ± 13.4%) vs. (65.3% ± 19.3%), P = 0.001) in the microchannel group than in the no-microchannel group. Conclusion: In patients with STEMI caused by plaque erosion, one-third manifested typical microchannel characteristics, and those with microchannels were associated with more severe luminal stenosis and more vulnerable plaque features than those without microchannels.