Unstable Carotid Research Articles

Expression of Circulating miR-17-92 Cluster and HDAC9 Gene in Atherosclerotic Patients with Unstable and Stable Carotid Plaques.

The miR-17-92 cluster and the HDAC9 gene are involved in inflammatory, apoptotic, and angiogenic processes that are activated in the vulnerable carotid plaque. The aim of this research was to determine whether expression of one or more of the miRs of the miR-17-92 cluster and/or HDAC9 expression could represent biomarkers for patients with unstable atherosclerotic carotid plaques. Plasma levels of miRs and HDAC9 expression in peripheral blood were analyzed by real-time PCR in patients with histologically classified stable or unstable plaques. No differences were observed between the two groups. Levels of the miR-17-92 cluster in plasma and HDAC9 gene expression in peripheral blood cannot be considered appropriate biomarkers to identify patients with unstable plaques at risk of rupture.

Identification of neovascularization by contrast-enhanced ultrasound to detect unstable carotid stenosis.

BackgroundPlaque neovascularization accompanies local inflammation and critically contributes to plaque instability. Correct identification of intraplaque neovascularization by contrast–enhanced ultrasound (CEUS) may provide an additional risk marker in carotid stenosis. This pilot study investigates the correlation between histological evaluation of carotid plaque specimens and pre-surgery CEUS to identify neovascularization.Methods17 patients with high-grade internal carotid artery (ICA) stenosis were studied. CEUS was performed in all patients shortly before carotid endarterectomy. Neovascularization, infiltration of T cells and macrophages along with intraplaque hemorrhage were studied in excised plaques by immunohistochemistry. Ultrasound-based four-level and two-level classification systems for neovascularization were used. CEUS findings were compared with histological findings.ResultsScores on the CEUS-based four-level and two-level classifications were robustly correlated with the density of intraplaque vessels (r = 0.635, p = 0.006 and r = 0.578, p = 0.015, respectively). Histological evaluation of regions with strong and prolonged intraplaque enhancement typically showed strong intraplaque neovascularization in conjunction with acute intraplaque hemorrhage. Moreover, higher grades of intraplaque neovascularization as determined by ultrasound were associated with a higher percentage of macrophage-rich areas.ConclusionCEUS is a technique well suited to gauge the degree of neovascularization of carotid plaques. Future research will have to define the reliability and validity of CEUS in everyday clinical practice. Further, our study suggests that CEUS may also be useful to pick up features of vulnerable plaques such as acute intraplaque hemorrhages.

Imaging of high-risk carotid plaques: ultrasound

Duplex ultrasonography has a well-established role in the assessment of the degree of stenosis caused by carotid atherosclerosis. This assessment is derived from Doppler velocity changes induced by the narrowing lumen of the artery. New research into the mechanisms for plaque rupture and atheroembolic stroke indicates that the degree of narrowing is an imperfect predictor of stroke risk, and that other factors, such as plaque composition and remodeling and biomechanical forces acting on the plaque, can play a role. New advances in ultrasound imaging technology have made it possible to investigate these measures of plaque vulnerability to identify pre-embolic unstable carotid plaques. Efforts have been made to quantify the morphologic appearance of the plaque in B-mode images and to correlate them with histology. Additional research has resulted in the first generation of clinically available 3-dimensional ultrasound transducers that reduce operator-dependence and variability. Finally, ultrasonography provides real-time imaging and physiologic information that can be utilized to measure disruptive forces acting on carotid plaques. We review some of these exciting developments in ultrasonography and discuss how these may impact clinical practice.

In This Issue

HomeCirculation ResearchVol. 120, No. 4In This Issue Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBIn This Issue Ruth Williams Ruth WilliamsRuth Williams Search for more papers by this author Originally published17 Feb 2017https://doi.org/10.1161/RES.0000000000000137Circulation Research. 2017;120:593miR-210 Enhances Atherosclerotic Plaque Stability (p 633)Download figureDownload PowerPointMicroRNA-210 stabilizes vulnerable atherosclerotic plaques, report Eken et al.Disruption or destabilization of atherosclerotic plaques often results in the formation of an occlusive thrombus, which leads to tissue ischemia and the onset of clinical symptoms of myocardial ischemia or stroke. Hence, identification and treatment of unstable plaques is likely to be highly beneficial to patients with advanced atherosclerotic disease. Because microRNAs (miRs) offer great potential as therapeutic agents, Eken and colleagues searched for differences in the abundance of miRs in patients with stable and unstable carotid plaques. In a comparison of ≈750 miRs expressed in atherosclerotic plaques, the team found that 8 miRs were differentially regulated between patients whose atherosclerosis was asymptomatic versus symptomatic (indicative of plaque instability). Of these, miR-210, present in the stable fibrous cap of atherosclerotic lesions, was the most significantly downregulated in unstable plaques. Furthermore, miR210 was also downregulated in animal models of atherosclerotic lesions, the team showed. And overexpression of this miR, using miR-210 mimics, increased plaque stability in such animals. Boosting miR-210 levels in vulnerable plaques might, therefore, be a means to prevent life-threatening plaque ruptures, say the authors.Intramyocardial CD133+ Cells in Refractory Angina (p 670)Download figureDownload PowerPointA trial of bone marrow stem cells for refractory angina yields inconclusive results, according to Wojakowski et al.Despite considerable progress in the treatment of coronary artery disease, there remain many patients for whom current therapies do not help. New approaches for such refractory angina patients are thus greatly needed. One potential treatment under study is transendocardial delivery of bone marrow stem cells. Indeed, recent studies have shown that such treatment reduces symptoms and improves quality of life in refractive angina patients. However, bone marrow contains a mixed population of cells, so it is possible that certain subpopulations of these cells are more effective than others in alleviating angina symptoms. CD133-positive bone marrow stem cells, for example, are known to have angiogenic potential, which might improve myocardial perfusion in patients. To test this idea, Wojakowski and colleagues administered transendocardial injections of CD133+ cells to patients with refractory angina. They observed no difference in myocardial perfusion or left ventricle ejection fraction between the test and control patients, but they suggest that with so few patients enrolled, the study might have lacked statistical power. Nevertheless, because the procedure was deemed safe, the authors suggest that a larger scale multicenter study is warranted.Pediatric CPC-Derived Exosome Therapy (p 701)Download figureDownload PowerPointDonor age and oxygen levels effect exosomes’ reparative potential, say Agarwal and colleagues.Stem and progenitor cells are being investigated for their potential to treat coronary artery disease (CAD). It is believed that these cells promote tissue repair via their paracrine effects on myocardial tissue or other noncardiac sites. Cardiac progenitor cells (CPCs), for example, release exosomes—small membrane-bound vesicles containing bioactive components—that have been shown in animal models to improve ventricular remodeling and promote healing after myocardial infarction. Evidence suggests that the effectiveness of stem cell therapies depends on oxygen levels and the age of the donor. To examine whether these factors also influence exosome therapies, Agarwal and colleagues isolated CPC exosomes from newborn babies, infants, and children undergoing heart surgery, and compared their reparative potential with and without hypoxic preconditioning. The team showed that, in rats suffering ischemia–reperfusion injuries, exosomes from newborns were the most effective at improving heart function. They also found that even though the potency of the exosomes diminished with increasing donor age, it could be restored by hypoxic preconditioning. The team went on to show that differences in the microRNA content of the exosomes were predictive of their effectiveness. Hence, it seems likely that microRNA analysis of exosomes from other cell types might reveal additional sources of exosome with high therapeutic potential. Previous Back to top Next FiguresReferencesRelatedDetails February 17, 2017Vol 120, Issue 4 Advertisement Article InformationMetrics © 2017 American Heart Association, Inc.https://doi.org/10.1161/RES.0000000000000137 Originally publishedFebruary 17, 2017 PDF download Advertisement

Expression of a metalloproteinase family of ADAMTS in human vulnerable carotid lesions.

ADAMTS family of metalloproteases (a disintegrin and metalloprotease with thrombospondin motifs) possesses high proteolytic activity especially regarding proteoglycans. Their expression pattern in carotid plaques is as-yet unknown. The aim of the study was therefore the analysis of expression of ADAMTS1, 4, 5, and 13 and their inhibitors TIMP-1 and TIMP-3 in stable and unstable carotid plaques. Atherosclerotic plaques were collected from 40 patients (29 men, 11 women, mean age 70 years) undergoing carotid endarterectomy. The specimens were categorized into two groups (stable/unstable) according to Redgrave und Rothwell (The Oxford Plaque Study, 2008). SYBR Green-based real-time PCR, histology, and immunohistochemistry were performed. All ADAMTS tested in our study were expressed in both stable and unstable plaques, especially in smooth muscle cells (SMCs) and macrophages. Analysis of the expression pattern on mRNA level showed significant higher expression of ADAMTS1 in unstable plaques compared with stable plaques (1.7-fold, P = 0.049). The expression of ADAMTS4 and 5 was also increased in unstable lesions; however, these changes were not statistically significant (1.2-fold, P = 0.667 and 1.6-fold, P = 0.077). Expression of TIMP-1 was significantly reduced in unstable plaques compared with stable ones (1.9-fold, P = 0.014). SMCs seem to be an important source of ADAMTS analyzed in our study. Furthermore, expression of ADAMTS1 was found to be increased in unstable carotid lesions and might potentially contribute to plaque vulnerability.

MicroRNA-210 Enhances Fibrous Cap Stability in Advanced Atherosclerotic Lesions.

In the search for markers and modulators of vascular disease, microRNAs (miRNAs) have emerged as potent therapeutic targets. To investigate miRNAs of clinical interest in patients with unstable carotid stenosis at risk of stroke. Using patient material from the BiKE (Biobank of Karolinska Endarterectomies), we profiled miRNA expression in patients with stable versus unstable carotid plaque. A polymerase chain reaction-based miRNA array of plasma, sampled at the carotid lesion site, identified 8 deregulated miRNAs (miR-15b, miR-29c, miR-30c/d, miR-150, miR-191, miR-210, and miR-500). miR-210 was the most significantly downregulated miRNA in local plasma material. Laser capture microdissection and in situ hybridization revealed a distinct localization of miR-210 in fibrous caps. We confirmed that miR-210 directly targets the tumor suppressor gene APC (adenomatous polyposis coli), thereby affecting Wnt (Wingless-related integration site) signaling and regulating smooth muscle cell survival, as well as differentiation in advanced atherosclerotic lesions. Substantial changes in arterial miR-210 were detectable in 2 rodent models of vascular remodeling and plaque rupture. Modulating miR-210 in vitro and in vivo improved fibrous cap stability with implications for vascular disease. An unstable carotid plaque at risk of stroke is characterized by low expression of miR-210. miR-210 contributes to stabilizing carotid plaques through inhibition of APC, ensuring smooth muscle cell survival. We present local delivery of miR-210 as a therapeutic approach for prevention of atherothrombotic vascular events.

358 - Pharmacological Inhibition of Myeloperoxidase Improves Endothelial Function and Stabilizes Atherosclerotic Lesions in a Mouse Model of Vulnerable Plaque

The involvement of myeloperoxidase (MPO) in human atherosclerotic plaque progression is well documented, including its potential role in plaque rupture that can cause acute myocardial infarction. Despite this, establishing a causal relationship between MPO and atherosclerosis-associated complications has proven difficult in mouse models. In the present study we employed a mouse model of atherosclerotic plaque instability (Circ Res 113:252) to examine the role of MPO in endothelial dysfunction and atherosclerotic plaque vulnerability. Unstable plaques were introduced in apolipoprotein E gene knockout (Apoe–/–) mice fed a Western diet for 13 weeks by placing a tandem stenosis around the right carotid artery after 6 weeks of diet, and MPO activity was partially blocked by oral administration of a 2-thioxanthine (AZM198). Unstable carotid plaques, but not stable plaques in the aortic root and arch, contained measurable MPO activity as assessed by the in vivo conversion of hydroethidine to 2-chloroethidium and non-invasive magnetic resonance imaging using MPO-gadolinium (bis-5-hydroxytryptamine-DTPA-Gd). Administration of AZM198 did not change circulating white blood cell counts, plasma concentrations of pro-inflammatory cytokines and lipids, nor did it affect atherosclerotic lesion size in the aortic root. In contrast, AZM198 significantly attenuated arterial MPO activity in unstable plaques and endothelial dysfunction in the abdominal aorta. Inhibition of MPO activity was associated with increased plaque stability in the carotid artery, as indicated by the increase in cap thickness and the cap-to-lesion ratio, without affecting necrotic core size and arterial monocytes. Together, these data indicate that vulnerable but not stable atherosclerotic lesions in Apoe–/– mice exhibit MPO activity, and that pharmacological inhibition of MPO stabilizes vulnerable plaques.

Effects of berberine on serum inflammatory factors and carotid atherosclerotic plaques in patients with acute cerebral ischemic stroke

This study aims to analyze the effect of berberine on serum inflammatory factors and carotid atherosclerotic plaques in ppatients with acute cerebral ischemic stroke(AIS). In the study, 120 patients with AIS were randomly divided into berberine group(n=60) and general group (n=60). The 60 cases in the general group were provided with general therapy according to the latest guidelines of diagnosis and treatment of AIS. The berberine group received berberine 300 mg(tid) in addition to the therapy of the general group. The levels of serum inflammatory factors, the nerve function defect grades and the indexes of carotid atherosclerosis plaques [including the total plaque area(TPA), intima-media thickness(IMT) and the number of unstable carotid atherosclerotic plaques] were measured and compared. The results indicated that the levels of serum inflammatory factors, the NIHSS(national institute of health stroke scales) cores and the indexes of carotid atherosclerosis plaques were not significantly different between the berberine groups of general group, with positive correlation between serum inflammatory factors and NIHSS scores(P<0.05). The levels of serum inflammatory factors and NIHSS scores of the berberine groups on 14 d were significantly lower than those on 1 d(P<0.05). The levels of serum inflammatory factors and NIHSS scores of the berberine group on 14 d were significantly lower than those of the general group(P<0.05). The TPA and the number of unstable carotid atherosclerotic plaques of the berberine groups on 90 d were significantly lower than those of general group, with significant differences(P<0.05). The IMT showed a downward trend, but with significant difference.The mRS(modified rankin scale) scores of the berberine group on 90 d were significantly lower, with a higher rate of short-term favorable prognosis (P<0.05). There was no significant difference in the incidence of adverse reactions between the two groups. This study showed that berberine in addition to the general therapy can significantly lower the levels of serum MIF and IL-6, reduce the degree of carotid atherosclerosis to some extent and improve neurological impairment and the prognosis of patients with AIS.

A role for autophagy in carotid atherosclerosis.

Autophagy has emerged in recent years as a critical cellular survival mechanism for cell homeostasis and may play a protective role in atherosclerosis. We aimed to review here the role autophagy plays in different cell types present in carotid atherosclerotic plaques and that may be associated with the development of unstable carotid atheroma plaque. We performed a thorough literature exploration in this area of research covering the three main cell types present in carotid atheroma plaques. Reviewed reports indicate that the role of autophagy in stable or unstable carotid atherosclerotic plaques depends on the different cell types and phenotypes, the stage and morphology of the plaque and the specific autophagy factor/s involved. Although defective autophagy could be one of the causes for carotid atheroma plaques to become unstable, it is important to take into account that autophagic players can act differentially in different cell types and different stages of the developed plaque. This review provides an overview of the role of autophagy in the main cell types in carotid atherosclerosis (i.e. macrophages, endothelial cells and smooth muscle cells).

Carotid Plaque Morphology in Asymptomatic Patients with and without Metabolic Syndrome

The aim of this study was to determine the impact of metabolic syndrome (MetS) on the morphology of carotid plaques, as evaluated using duplex ultrasound (DUS) with computer-assisted analysis. In this cross-sectional observational study, we analyzed 148 carotid artery plaques in asymptomatic patients. Data were obtained via clinical and laboratory examinations, and DUS was performed by a single operator. All plaques were scanned in a longitudinal fashion, and the best segment was selected, recorded, and evaluated using dedicated software. The main software-based analyses included gray-scale median (GSM) measurements and carotid plaque morphology histograms. MetS was identified in 51.8% of patients. Comparisons of patients with MetS and patients without MetS indicated that the former patients used more classes of antihypertensive drugs (2.49 vs. 1.93; P=0.004) and were treated with statins for a longer period (71.08 vs. 49.17months; P=0.003). Most patients of both types exhibited moderate carotid artery stenosis ranging from 50% to 69% (n=62; 37.3%), and MetS was not associated with an increased prevalence of severe carotid artery stenosis. The mean GSM was greater in the MetS group than in the non-MetS group (74.18 vs. 61.63; P=0.012). The histogram analysis revealed that there were lower quantities of blood and fat (2.91 vs. 3.88; P=0.006; 10.21 vs. 15.08; P=0.004, respectively) and more fibrous tissue (19.93 vs. 14.55; P=0.015) in the carotid plaques of patients with MetS than in the carotid plaques of patients without MetS. The present study demonstrated that MetS did not affect the stenosis grade or did it lead to unstable carotid plaques.

Gene and Protein Expression of Chemokine (C-C-Motif) Ligand 19 is Upregulated in Unstable Carotid Atherosclerotic Plaques

The aim was to investigate the expression of genes associated with carotid plaque instability and their protein products at a local and systemic level. Carotid plaques from 24 patients undergoing carotid endarterectomy (CEA) were classified as stable or unstable using clinical, histological, ultrasound, and transcranial Doppler criteria, and compared using whole genome microarray chips. Initial results of differentially expressed genes were validated by quantitative reverse transcriptase polymerase chain reaction in an independent group of 96 patients undergoing CEA. The protein product of genes significantly differentially expressed between patients with stable and unstable plaques were analysed by plaque immunohistochemistry and serum protein quantification by enzyme-linked immunosorbent assay on a further independent cohort. Expression of chemokine (c-c-motif) ligand 19 (CCL19) was significantly upregulated in plaques from patients with clinically unstable disease (p<.001). Cathepsin G expression was upregulated in histologically unstable plaques (p=.04). Serum concentration of CCL19 was significantly higher in patients with clinically unstable plaques (p=.02). Immunohistochemical staining for CCL19 demonstrated positive staining in histologically and clinically unstable plaques (p=.03). CCL19 also co-localised with CD3+ T-cell lymphocytes in the core region, around where CCL19 was expressed. CCL19 is significantly overexpressed in patients with unstable carotid atherosclerotic plaques and may be a possible novel biomarker for identifying high-risk patients in whom more urgent intervention may be indicated.

The prevalence of carotid plaque with different stability and its association with metabolic syndrome in China: The Asymptomatic Polyvascular Abnormalities Community study.

Few studies have investigated the prevalence of carotid plaque with different stability in Chinese. As is well known, carotid atherosclerosis is tightly associated with metabolic syndrome (MetS); however, the data about the association between the presence of carotid plaque with different stability and MetS was limited. The aim of our study was to investigate the prevalence of carotid plaque with different stability and its potential association with MetS in general Chinese population.The Asymptomatic Polyvascular Abnormalities Community study is a community-based study to investigate the epidemiology of asymptomatic polyvascular abnormalities in Chinese adults. A total of 5393 participants were finally eligible and included in this study. The carotid plaque and its stability were assessed using ultrasonography. The MetS was defined using the criteria from US National Cholesterol Education Program-Adult Treatment Panel III. Data were analyzed with multivariate logistic regression models.Of the 5393 subjects, 1397 (25.9%) participants had stable carotid plaque, 1518 (28.1%) had unstable carotid plaque in participants, and 1456 (27.0%) had a MetS. MetS was, respectively, significantly associated with the prevalence of carotid plaque (odds ratio [OR]: 1.25; 95% confidence interval [CI]: 1.07, 1.47), stable carotid plaque (OR: 1.23; 95% CI: 1.02,1.48), and unstable carotid plaque (OR: 1.27; 95% CI: 1.03,1.56) after adjusting for age, gender, level of education, income, smoking, drinking, physical activity, body mass index, low-density lipoprotein, and high-sensitivity C-reactive protein. With the number of MetS components, the prevalence of carotid plaque, stable carotid plaque, and unstable carotid plaque significantly increased (P for trend <0.0001), respectively.In summary, the prevalence of carotid plaque was 54.1%, stable carotid plaque was 25.9%, and unstable carotid plaque was 28.1%. Our study revealed that the prevalence of carotid plaque, stable carotid plaque, and unstable carotid plaque was, respectively, significantly associated with MetS in the general population.

Commentary on ‘Risk of Recurrent Stroke in Patients with Symptomatic Mild (20–49% NASCET) Carotid Stenosis’

Commentary on ‘Risk of Recurrent Stroke in Patients with Symptomatic Mild (20–49% NASCET) Carotid Stenosis’

Adipo/cytokines in atherosclerotic secretomes: increased visfatin levels in unstable carotid plaque.

BackgroundNovel pro-inflammatory and anti-inflammatory derivatives from adipose tissue, known as adipokines, act as metabolic factors. The aim of this study was to analyse the secreted expression of different adipo/cytokines in secretomes of unstable carotid atherosclerotic plaque versus non-atherosclerotic mammary artery.MethodsWe evaluated the secretion levels of adiponectin, visfatin, lipocalin-2, resistin, IL-6 and TNFR2 by ELISA in human secretomes from cultured unstable carotid atherosclerotic plaque (n = 18) and non-atherosclerotic mammary artery (n = 13). We also measured visfatin serum levels in patients suffering from atherosclerosis and in a serum cohort of healthy subjects (n = 16).ResultsWe found that visfatin levels were significantly increased in unstable carotid atherosclerotic plaque secretome than in non-atherosclerotic mammary artery secretome. No differences were found with regard the other adipo/cytokines studied. Regarding visfatin circulating levels, there were no differences between unstable carotid atherosclerotic plaque and non-atherosclerotic mammary artery group. However, these visfatin levels were increased in comparison to serum cohort of healthy subjects.ConclusionsOf all the adipo/cytokines analysed, only visfatin showed increased levels in secretomes of unstable carotid atherosclerotic plaque. Additional human studies are needed to clarify the possible role of visfatin as prognostic factor of unstable carotid atherosclerotic plaque.

Assessment of cerebral embolism and vascular reserve parameters in patients with carotid artery stenosis

AimCarotid artery stenosis can result in the brain tissue injury related to the intracranial aterial flow disturbances as well as microembolic complications. The choice of the proper therapy in patients with carotid artery stenosis, especially asymptomatic, remains still a significant clinical problem. The study aim was an assessment of the cerebral embolism and brain vascular reserve parameters in patients with carotid artery stenosis regarding the occurrence of the clinical symptoms, the degree of stenosis as well as plaque morphology. MethodsThe study included 60 patients, with internal carotid artery stenosis. The degree of stenosis, the atherosclerotic plaque surface and morphology were assessed by the means of Duplex Doppler ultrasound. Cerebrovascular reactivity (vasomotor reactivity reserve test and Breath Holding Index) and monitoring of the microembolic signals (MES) were assessed with transcranial Doppler ultrasound examination (TCD). ResultsThe vasoreactivity parameters were significantly lower in the group of patients with stenosis ≥70% and in patients with ulcerations on the plaque surface. Microembolic signals were recorded significantly more often in symptomatic patients; in patients with stenosis ≥70%; in patients with ulcerations on the plaque surface and those with hypoechogenic plaque structure. ConclusionsMicroembolic signals in patients with symptomatic carotid stenosis are one of the ultrasound features of unstable carotid stenosis. Worse reactivity parameters of the cerebral arteries are associated with the presence of a large degree of carotid artery stenosis.

Circulating Chemerin Is Associated With Carotid Plaque Instability, Whereas Resistin Is Related to Cerebrovascular Symptomatology.

The rupture of unstable carotid atherosclerotic plaques is one of the main causes of cerebrovascular ischemic events. There is need for circulating markers that can predict plaque instability and risk of stroke. Proinflammatory chemerin, leptin, and resistin, along with anti-inflammatory adiponectin, are adipokines with direct influence on vascular function. We investigated the association of circulating adipokines with carotid plaque instability and cerebrovascular symptomatology. Neurologically symptomatic and asymptomatic patients (n=165) scheduled for carotid endarterectomy were recruited. Fasting blood samples were collected preoperatively; adiponectin and leptin levels were determined by radioimmunoassay; and chemerin and resistin levels were measured by enzyme-linked immunosorbent assays. The instability of plaque specimens was assessed using gold-standard histological classifications. Chemerin was significantly associated with plaque instability. The fully adjusted model, accounting for age, sex, body mass index, high-sensitivity C-reactive protein, type 2 diabetes mellitus, and circulating adiponectin, leptin, and resistin, yielded an odds ratio of 0.991 (95% confidence interval 0.985-0.998) for plaque instability per unit increase in chemerin. High leptin levels were significantly associated with presence of specific features of plaque instability. In subjects with type 2 diabetes mellitus, resistin levels were significantly elevated in symptomatic when compared with asymptomatic subjects (P=0.001) and increased the risk of cerebrovascular symptomatology (adjusted odds ratio 1.264, 95% confidence interval 1.004-1.594). Low chemerin and high resistin levels were associated with carotid disease severity, suggesting that these adipokines may act as potential markers for plaque instability and stroke risk. Future studies are needed to assess causation between circulating adipokines and plaque instability.

The Urotensin II System and Carotid Atherosclerosis: A Role in Vascular Calcification

Background and Aims: The aims of the present study were to determine the expression of urotensin II (UII), urotensin-II related peptide (URP), and their receptor (UT) in stable and unstable carotid atherosclerosis, and determine the effects of UII on human aortic smooth muscle cell (SMCs) calcification.Methods and Results: We examined UII, URP, and UT protein expression in 88 carotid endarterectomy specimens using immunohistochemistry. Expression of UII, URP, and UT was more evident in unstable compared to stable plaques (P < 0.05). Multivariate Spearman correlation analyses revealed significant positive correlations between UII, URP and UT overall staining and presence of calcification, severity of stenosis and inflammation (P < 0.05). Subjects undergoing carotid endarterectomy had significantly higher plasma UII levels, as assessed by ELISA, when compared with normolipidemic healthy control subjects (P < 0.05). Incubation of human aortic SMCs cultured in phosphate media with varying concentrations of UII resulted in a significant increase in calcium deposition and alkaline phosphatase activity. UII also significantly increased β-catenin translocation and expression of ALPL, BMP2, ON, and SOX9 (P < 0.05). Incubation of cells with phosphate medium alone increased the expression of the pre-UT and mature UT (P < 0.01), and addition of UII had a synergistic effect on pre-UT protein expression (P < 0.001) compared to phosphate medium alone.Conclusions: Upregulation of UII, URP, and UT in unstable carotid endarterectomy plaques and plasma, and the stimulatory effect of UII on vascular smooth muscle cell calcification suggest that the UII system may play a role in the pathogenesis of vascular calcification and stability of atherosclerosis.

Blood Pressure Lowering Treatment in Patients with Carotid Artery Stenosis.

Stroke is the second most common cause of death and the most common cause of disability worldwide. Up to 30% of ischaemic strokes are caused by carotid atherosclerosis, usually due to thromboemboli from an atherosclerotic plaque at the carotid bifurcation. High blood pressure is an important risk factor for atherosclerosis, the development of unstable carotid plaques, and ischaemic strokes. Differentiation between asymptomatic and symptomatic carotid atherosclerosis is critical to treatment management because of the difference in natural history. Intensive medical treatment including blood pressure lowering medication reduces the risk of both primary and secondary vascular events in patients at risk. This review summarises recent data on blood pressure management in patients with carotid artery stenosis.

Abstract 3: Targeting Macrophage Necroptosis for Therapeutic and Diagnostic Interventions to Treat Atherosclerosis

Background: Atherosclerosis results from maladaptive inflammation driven primarily by macrophages, whose recruitment and proliferation drive plaque progression. In advanced plaques, macrophage death contributes centrally to the formation of plaque necrosis, which underlies the instability that promotes plaque rupture and myocardial infarction. As such, targeting macrophage cell death pathways may offer promise for the stabilization of vulnerable plaques. Necroptosis is a recently discovered pathway of programmed cell necrosis regulated by RIP3 and MLKL kinases that in contrast to apoptosis, induces a pro-inflammatory state. We hypothesize that atherogenic ligands within the plaque promote macrophage necroptosis and this process underlies necrotic core formation and drives atherosclerotic plaque instability. Results: In humans with unstable carotid atherosclerosis, expression of RIP3 and MLKL is increased and MLKL phosphorylation, a key step in the commitment to necroptosis, is detected in advanced atheromas. Investigation of the molecular mechanisms underlying plaque necroptosis showed that macrophages treated with oxidized LDL have increased expression of necroptotic genes RIP3 and MLKL through ROS-dependent activation of the promoter region and increased RIP3 and MLKL phosphorylation. Combined treatment with oxLDL and DAMPs (damage associated molecular patterns) amplified macrophage necroptotic cell death, indicating that additional inflammatory stimuli present in the lesion could act synergistically to promote necroptosis. Using a radiotracer developed with the necroptosis inhibitor Nec-1, we show that 123 I-Nec1 localizes specifically to atherosclerotic plaques in Apoe-/- mice, and its uptake is tightly correlated to lesion areas by ex vivo nuclear imaging. Furthermore, treatment of Apoe-/- mice with established atherosclerosis with Nec-1 reduced lesion size and markers of plaque instability, including necrotic core formation. Conclusions: Our findings offer molecular insight into the mechanisms of macrophage cell death that drive necrotic core formation in atherosclerosis and suggest that this pathway can be used as both a diagnostic and therapeutic tool for the treatment of unstable atherosclerosis.

Endovascular Treatment of Extracranial Internal Carotid Pseudoaneurysm: Description of Three Cases

The aim of this study is to explore the possibility of endovascular treatment of internal carotid artery pseudoaneurysm (PSA). These lesions are difficult to treat with a surgical approach, especially if they are located extracranially and close to the skull base. Endovascular stent placement in symptomatic and unstable extracranial internal carotid PSA was found to be safe and effective. Depending on hemodynamic aspects, complete local exclusion of aneurysmal formation is achieved in few months. We present three patients with carotid dissection and PSA formation that have been successfully treated by stent placement.