Unstable Carotid Atherosclerotic Plaques Research Articles

Characterization of the proteome of stable and unstable carotid atherosclerotic plaques using data-independent acquisition mass spectrometry

BackgroundCurrently, noninvasive imaging techniques and circulating biomarkers are still insufficient to accurately assess carotid plaque stability, and an in-depth understanding of the molecular mechanisms that contribute to plaque instability is still lacking.MethodsWe established a clinical study cohort containing 182 patients with carotid artery stenosis. After screening, 39 stable and 49 unstable plaques were included in the discovery group, and quantitative proteomics analysis based on data independent acquisition was performed for these plaque samples. Additionally, 35 plaques were included in the validation group to validate the proteomics results by immunohistochemistry analysis.ResultsA total of 397 differentially expressed proteins were identified in stable and unstable plaques. These proteins are primarily involved in ferroptosis and lipid metabolism-related functions and pathways. Plaque validation results showed that ferroptosis- and lipid metabolism-related proteins had different expression trends in stable plaques versus unstable fibrous cap regions and lipid core regions. Ferroptosis- and lipid metabolism-related mechanisms in plaque stability were discussed.ConclusionsOur results may provide a valuable strategy for revealing the mechanisms affecting plaque stability and will facilitate the discovery of specific biomarkers to broaden the therapeutic scope.

RNA Sequencing Reveals the Differentially Expressed circRNAs between Stable and Unstable Carotid Atherosclerotic Plaques.

This study aimed to identify circular RNA profiles (circRNAs) via high-throughput RNA sequencing and distinguish the differentially expressed (DE) circRNAs between stable and unstable plaques. RNA sequencing was performed on unstable and stable carotid plaque samples obtained from patients with carotid artery stenosis. DE circRNAs were screened, and six DE circRNAs were verified using quantitative real-time PCR (qRT-PCR). Functional evaluation of the DE circRNAs was conducted via Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. We screened 344 DE circRNAs in unstable plaques, consisting of 342 upregulated and 2 downregulated circRNAs. GO analysis showed that the host genes of the upregulated circRNAs were related to ER to Golgi transport vesicle membrane, endocytic vesicle membrane, and Ran GTPase binding. KEGG analysis revealed that the host genes of the upregulated circRNAs were primarily associated with protein processing in endoplasmic reticulum, lysine degradation, homologous recombination, epithelial cell signaling in Helicobacter pylori infection, and yersinia infection. The results of qRT-PCR verified three upregulated DE circRNAs and two downregulated DE circRNAs in unstable plaques. Hsa-circ-0001523, hsa-circ-0008950, hsa-circ-0000571, hsa-circ-0001946, and hsa-circ-0000745 may be involved in regulating the stability of atherosclerotic plaques and serves as a therapeutic target for unstable plaques.

Identification of immune cell infiltration and diagnostic biomarkers in unstable atherosclerotic plaques by integrated bioinformatics analysis and machine learning.

ObjectiveThe decreased stability of atherosclerotic plaques increases the risk of ischemic stroke. However, the specific characteristics of dysregulated immune cells and effective diagnostic biomarkers associated with stability in atherosclerotic plaques are poorly characterized. This research aims to investigate the role of immune cells and explore diagnostic biomarkers in the formation of unstable plaques for the sake of gaining new insights into the underlying molecular mechanisms and providing new perspectives for disease detection and therapy.MethodUsing the CIBERSORT method, 22 types of immune cells between stable and unstable carotid atherosclerotic plaques from RNA-sequencing and microarray data in the public GEO database were quantitated. Differentially expressed genes (DEGs) were further calculated and were analyzed for enrichment of GO Biological Process and KEGG pathways. Important cell types and hub genes were screened using machine learning methods including least absolute shrinkage and selection operator (LASSO) regression and random forest. Single-cell RNA sequencing and clinical samples were further used to validate critical cell types and hub genes. Finally, the DGIdb database of gene–drug interaction data was utilized to find possible therapeutic medicines and show how pharmaceuticals, genes, and immune cells interacted.ResultsA significant difference in immune cell infiltration was observed between unstable and stable plaques. The proportions of M0, M1, and M2 macrophages were significantly higher and that of CD8+ T cells and NK cells were significantly lower in unstable plaques than that in stable plaques. With respect to DEGs, antigen presentation genes (CD74, B2M, and HLA-DRA), inflammation-related genes (MMP9, CTSL, and IFI30), and fatty acid-binding proteins (CD36 and APOE) were elevated in unstable plaques, while the expression of smooth muscle contraction genes (TAGLN, ACAT2, MYH10, and MYH11) was decreased in unstable plaques. M1 macrophages had the highest instability score and contributed to atherosclerotic plaque instability. CD68, PAM, and IGFBP6 genes were identified as the effective diagnostic markers of unstable plaques, which were validated by validation datasets and clinical samples. In addition, insulin, nivolumab, indomethacin, and α-mangostin were predicted to be potential therapeutic agents for unstable plaques.ConclusionM1 macrophages is an important cause of unstable plaque formation, and CD68, PAM, and IGFBP6 could be used as diagnostic markers to identify unstable plaques effectively.

Identification of hub genes and regulatory networks in histologically unstable carotid atherosclerotic plaque by bioinformatics analysis

ObjectiveThis study identified underlying genetic molecules associated with histologically unstable carotid atherosclerotic plaques through bioinformatics analysis that may be potential biomarkers and therapeutic targets.MethodsThree transcriptome datasets (GSE41571, GSE120521 and E-MTAB-2055) and one non-coding RNA dataset (GSE111794) that met histological grouping criteria of unstable plaque were downloaded. The common differentially expressed genes (co-DEGs) of unstable plaques identified from three mRNA datasets were annotated by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomics (KEGG). A protein–protein interaction (PPI) network was constructed to present the interaction between co-DEGs and screen out hub genes. MiRNet database and GSE111794 dataset were used to identify the miRNAs targeting hub genes. Associated transcription factors (TFs) and drugs were also predicted. These predicted results were used to construct miRNA/TFs-hub gene and drug-hub gene regulatory networks.ResultsA total of 105 co-DEGs were identified, including 42 up-regulated genes and 63 down-regulated genes, which were mainly enriched in collagen-containing extracellular matrix, focal adhesion, actin filament bundle, chemokine signaling pathway and regulates of actin cytoskeleton. Ten hub genes (up-regulated: HCK, C1QC, CD14, FCER1G, LCP1 and RAC2; down-regulated: TPM1, MYH10, PLS3 and FMOD) were screened. HCK and RAC2 were involved in chemokine signaling pathway, MYH10 and RAC2 were involved in regulation of actin cytoskeleton. We also predicted 12 miRNAs, top5 TFs and 25 drugs targeting hub genes. In the miRNA/TF-hub gene regulatory network, PLS3 was the most connected hub genes and was targeted by six miRNAs and all five screened TFs. In the drug-hub gene regulatory network, HCK was targeted by 20 drugs including 10 inhibitors.ConclusionsWe screened 10 hub genes and predicted miRNAs and TFs targeting them. These molecules may play a crucial role in the progression of histologically unstable carotid plaques and serve as potential biomarkers and therapeutic targets.

Transcriptomic and Proteomic Profiling of Human Stable and Unstable Carotid Atherosclerotic Plaques.

Atherosclerosis is a chronic inflammatory disease with high prevalence and mortality. The rupture of atherosclerotic plaque is the main reason for the clinical events caused by atherosclerosis. Making clear the transcriptomic and proteomic profiles between the stabe and unstable atherosclerotic plaques is crucial to prevent the clinical manifestations. In the present study, 5 stable and 5 unstable human carotid atherosclerotic plaques were obtained by carotid endarterectomy. The samples were used for the whole transcriptome sequencing (RNA-Seq) by the Next-Generation Sequencing using the Illumina HiSeq, and for proteome analysis by HPLC-MS/MS. The lncRNA-targeted genes and circRNA-originated genes were identified by analyzing their location and sequence. Gene Ontology and KEGG enrichment was carried out to analyze the functions of differentially expressed RNAs and proteins. The protein-protein interactions (PPI) network was constructed by the online tool STRING. The consistency of transcriptome and proteome were analyzed, and the lncRNA/circRNA-miRNA-mRNA interactions were predicted. As a result, 202 mRNAs, 488 lncRNAs, 91 circRNAs, and 293 proteins were identified to be differentially expressed between stable and unstable atherosclerotic plaques. The 488 lncRNAs might target 381 protein-coding genes by cis-acting mechanisms. Sequence analysis indicated the 91 differentially expressed circRNAs were originated from 97 protein-coding genes. These differentially expressed RNAs and proteins were mainly enriched in the terms of the cellular response to stress or stimulus, the regulation of gene transcription, the immune response, the nervous system functions, the hematologic activities, and the endocrine system. These results were consistent with the previous reported data in the dataset GSE41571. Further analysis identified CD5L, S100A12, CKB (target gene of lncRNA MSTRG.11455.17), CEMIP (target gene of lncRNA MSTRG.12845), and SH3GLB1 (originated gene of hsacirc_000411) to be critical genes in regulating the stability of atherosclerotic plaques. Our results provided a comprehensive transcriptomic and proteomic knowledge on the stability of atherosclerotic plaques.

Association of tumor necrosis factor-alpha and interleukin-10 levels with ultrasound characteristics of atherosclerotic plaques in patients with essential hypertension

Aim. To study the association of ultrasound characteristics of carotid atherosclerotic plaques (ASPs) with the concentration of tumor necrosis factor-alpha (TNFα) and interleukin-10 (IL-10) in patients with essential hypertension.Material and methods. The study included 117 patients (men, 75; women, 42) with essential hypertension aged 40 to 75 years (mean age, 55,8±7,5 years). All patients underwent anthropometric measurements (height, weight, body mass index, waist circumference), assessment of blood pressure and heart rate, blood tests (levels of glucose, creatinine with the calculation of glomerular filtration rate using CKD-EPI equation, lipid profile), duplex ultrasound of the carotid arteries. Also, the blood concentration of TNFα and IL-10 by the enzyme-linked immunosorbent assay using CYTOKIN-STIMUL-BEST (Novosibirsk,Russia) kit was determined.Results. According to the results of carotid duplex ultrasound, 3 groups of patients were identified. Group 1 included 48 patients with homogeneous hyperechoic ASPs; group 2 — 56 patients with dominant hyperechoic ASPs (>50% of areas); group 3 — 13 patients with anechoic, unstable, low-density ASPs. TNFα concentration in group 3 patients, amounting to 10,51±2.23 pg/ml, was significantly higher than in patients of group 1 (7,26±0,64 pg/ml (p<0,001)) and group 2 (8,93±0,98 pg/ml (p<0,001)). Similar results were obtained for IL-10. The logistic regression showed that the TNFα concentration is an independent factor associated with unstable ASsP (relative risk, 2,72; 95% confidence interval 1,44-5,15 (p<0,02)). It was also revealed that TNFα >10 pg/ml increased the risk of ASP instability by ~8 times.Conclusion. An increase in TNFα >10 pg/ml with a high specificity (95%) was associated with vulnerable unstable carotid ASPs.

IGFBP6 Is Downregulated in Unstable Carotid Atherosclerotic Plaques According to an Integrated Bioinformatics Analysis and Experimental Verification.

Aims: To investigate the differentially expressed genes (DEGs) and molecular interaction in unstable atherosclerotic carotid plaques.Methods: Gene expression datasets GSE41571, GSE118481, and E-MTAB-2055 were analyzed. Co-regulated DEGs in at least two datasets were analyzed with the enrichment of Gene Ontology Biological Process (GO-BP), Kyoto Encyclopedia of Genes and Genomes (KEGG), protein-protein interaction (PPI) networks, interrelationships between miRNAs/transcriptional factors, and their target genes and drug-gene interactions. The expression of notable DEGs in human carotid artery plaques and plasma was further identified.Results: The GO-BP enrichment analysis revealed that genes associated with inflammatory response, and extracellular matrix organization were altered. The KEGG enrichment analysis revealed that upregulated DEGs were enriched in the tuberculous, lysosomal, and chemokine signaling pathways, whereas downregulated genes were enriched in the focal adhesion and PI3K/Akt signaling pathway. Collagen type I alpha 2 chain (COL1A2), adenylate cyclase 3 (ADCY3), C-X-C motif chemokine receptor 4 (CXCR4), and TYRO protein tyrosine kinase binding protein (TYROBP) might play crucial roles in the PPI networks. In drug–gene interactions, colony-stimulating factor-1 receptor had the most drug interactions. Insulin-like growth factor binding protein 6 (IGFBP6) was markedly downregulated in unstable human carotid plaques and plasma. Under a receiver operating characteristic curve analysis, plasma IGFBP6 had a significant discriminatory power (AUC, 0.894; 95% CI, 0.810–0.977), with a cutoff value of 142.08 ng/mL.Conclusions: The genes COL1A2, ADCY3, CXCR4, and TYROBP are promising targets for the prevention of unstable carotid plaque formation. IGFBP6 may be an important biomarker for predicting vulnerable plaques.

Value of superb micro-vascular imaging in predicting ischemic stroke in patients with carotid atherosclerotic plaques.

BACKGROUNDUnstable carotid atherosclerotic plaques are prone to cause ischemic stroke. Contrast-enhanced ultrasound (CEUS) is the primary method of assessing plaque stability, but CEUS cannot be a method for screening for unstable plaque. The emergence of superb micro-vascular imaging (SMI) offers the possibility of clinically screening for unstable plaqueAIMTo investigate the value of SMI in predicting ischemic stroke in patients with carotid atherosclerotic plaques.METHODSPatients with carotid atherosclerotic plaques (luminal stenosis of 50%-70%) were enrolled into the present study. All patients received conservative medication. The patient's clinical baseline data, serological data, CEUS and SMI data were analyzed. All patients underwent a 3-year follow-up. The follow-up endpoint was the occurrence of ischemic stroke and patients were divided into stroke group and non-stroke group according to whether the prognosis occurred or not. Subsequently, the difference in clinical data was compared, the correlation of SMI and CEUS was analyzed, and multiple Cox regression and receiver operating characteristic curve were applied to investigate the value of SMI and CEUS in predicting cerebral arterial thrombosis in three years.RESULTSIn this study, 43 patients were enrolled in the stroke group and 82 patients were enrolled in the non-stroke group. Cox regression revealed that SMI level (P = 0.013) and enhancement intensity (P = 0.032) were the independent factors influencing ischemic stroke. There was a positive correlation between SMI level and enhancement intensity (r = 0.737, P = 0.000). The area under curve of SMI level predicting ischemic stroke was 0.878. The best diagnostic point was ≥ level II, and its sensitivity and specificity was 86.05% and 79.27%. The area under curve of enhancement intensity predicting ischemic stroke was 0.890. The best diagnostic point was 9.92 db, and its sensitivity and specificity was 88.37% and 89.02%. As the SMI level gradually increased, the incidence of ischemic stroke increased gradually (X2 = 108.931, P = 0.000).CONCLUSIONSMI can be used as a non-invasive method of screening for unstable plaques and may help prevent ischemic stroke.

Rs10230207 genotype confers changes in HDAC9 and TWIST1, but not FERD3L in lymphoblasts from patients with intracranial aneurysm.

Intracranial aneurysms (IA) are weakened outpouchings of the arterial wall in the cerebrovasculature. Rupture of an IA often leads to devastating consequences. The early identification of IA patients is crucial for management of their condition. A genetic variant at rs10230207, located nearby the HDAC9, TWIST1, and FERD3L genes, is associated with IA. HDAC9 is a class IIa histone deacetylase that mediates vascular smooth muscle cell dysfunction. TWIST1 is a mechanosensitive transcription factor and its expression is reduced in unstable carotid atherosclerotic plaques. In this study, the expression of the HDAC9, TWIST1, and FERD3L genes was characterized and associated with the presence of the rs10230207 genetic variant. Allelic discrimination and gene expression analysis were performed using lymphoblasts from 85 population controls and 109 IA patients. Subjects that were heterozygous (GT) within rs10230207 were 4.32 times more likely to have an IA than those that were homozygous for the reference allele (GG; 95%CI 1.23 to 14.16). Subjects that were homozygous (TT) were 8.27 times more likely to have an IA than those that were GG (95%CI 2.45 to 27.85). While the presence of the risk allele was not associated with changes in FERD3L gene expression, the risk allele was associated with increased HDAC9 and decrease in TWIST1 mRNA expression. The significant inverse correlation between HDAC9 and TWIST1 gene expression suggests that changes in the expression of both of genes may contribute to the formation of IAs.

Expression and Cellular Localization of CXCR4 and CXCL12 in Human Carotid Atherosclerotic Plaques.

The CXCR4/CXCL12 complex has already been associated with progression of atherosclerosis; however, its exact role is yet unknown. The aim of this study was to analyse the expression and cellular localization of CXCL12 and its receptor CXCR4 in human carotid atherosclerotic plaques. Carotid plaques (n = 58; 31 stable, 27 unstable, based on histological characterization of plaque morphology) were obtained during carotid endarterectomy, and 10 healthy vessels were used as a control. Expression of cxcr4, cxcr7, cxcl12, ccl2/ccr2 and csf1/csf1r was analysed at mRNA, and level expression of CXCR4, CXCR7 and CXCL12 was analysed at protein level. Cellular localization was determined using consecutive and double immunohistochemical (IHC) staining and microdissection. At mRNA level, cxcr4, cxcr7 and cxcl12 were significantly higher expressed in stable carotid plaques compared with controls (p = 0.011, p < 0.001 and p < 0.001). Cxcl12 mRNA expression was successively augmented toward unstable plaques (p < 0.001). At protein level, CXCR4, CXCR7 and CXCL12 expression was significantly increased in both stable (p = 0.001, p < 0.001 and p = 0.035, respectively) and unstable (p = 0.003, p < 0.001 and p = 0.045, respectively) plaques compared with controls. Using IHC, CXCR4 was particularly localized in macrophages and small neovessels. Microdissection confirmed strongest expression of cxcr4 in macrophages within atherosclerotic plaques. Leukocytes and smooth muscle cells showed cxcr4 expression as well. For cxcl12, only microdissected areas with macrophages were positive. Expression of CXCR4 and CXCL12 was significantly increased in both stable and unstable carotid atherosclerotic plaques compared with healthy vessels, both at mRNA and protein level. CXCR4 and CXCL12 were localized particularly in macrophages.

MORPHOLOGICAL CHARACTERISTICS OF CORONARY AND CAROTID ATHEROSCLEROTIC PLAQUES IN PATIENTS WITH MYOCARDIAL INFARCTION

Aim - to study the correlation between the thickness of the fibrous cap and collagen in the coronary and carotid plaques in patients with myocardial infarction. Materials and methods. The objects of the study were 81 coronary and carotid atherosclerotic plaques obtained during autopsy study of 15 patients who died from complications of myocardial infarction. Histological and morphometric study and immunohistochemistry were performed. Immunohistochemical examination was carried out using monoclonal antibodies against collagen types II, III, IV, VI, VII. Results. There is a combination of complicated, unstable and stable coronary and carotid atherosclerotic plaques in patients with myocardial infarction. Unstable atherosclerotic plaque is characterized by thinning of the fibrous cap mainly in the peripheral areas and the growth of destructive changes in the collagen types III, IV and VI. Conclusion. There is a critical thinning in the caps of unstable carotid and coronary plaques in myocardial infarction with signs of disorganization of collagen, leading to decreased resistance to mechanical stress of this type of 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).

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.

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.

Assessment of vulnerable and unstable carotid atherosclerotic plaques on endarterectomy specimens.

The types of lesion instability responsible for the majority of acute coronary events frequently include plaque disruption and plaque erosion with superimposed thrombosis. The term 'vulnerable plaque is used to describe atherosclerotic (ATS) plaques that are particularly prone to rupture and susceptible to thrombus formation, such as the thin-cap fibroatheroma (TCFA). The aim of the present study was to assess the morphological and histological differences between plaques that are unstable and those that are vulnerable to instability. Carotid artery endarterectomy specimens were obtained from 26 patients with carotid artery stenosis, consisting of 20 men and 6 women (age range, 35-80 years). Histological and morphometric methods were used to visualize and characterize the ATS plaques. Among the 26 carotid ATS plaques, 23% were stable, 23% were unstable and 54% were vulnerable. With regard to morphometric characteristics, the following mean values were obtained for the TCFA and unstable plaques, respectively: Fibrous cap thickness, 21.91 and 11.66 µM; proportion of necrotic core area in the total plaque area, 25.90 and 22.03%; and the proportion of inflammatory area in the total plaque area, 8.41 and 3.04%. No plaque calcification was observed in any of them. Since ATS coronary artery disease is considerably widespread and fatal, it is crucial to further study ATS lesions to obtain an improved understanding of the nature of vulnerable and unstable plaques. The methods used to detect plaque size, necrotic core area and fibrous cap thickness are considered to be particularly useful for identifying vulnerable and unstable plaques.

Abstract 124: Association of AdipoR2 mRNA Expression on Peripheral Monocytes With Carotid Plaque Instability

Adiponectin, an adipose tissue secreted protein, possesses anti-atherosclerotic properties. Its effects are partly mediated through its action on monocytes, via receptors, AdipoR1 and AdipoR2. Circulating monocytes play a crucial role both in plaque initiation and in the progression of atherosclerosis. The aim of this ongoing study is to investigate for the first time whether there is differential expression of AdipoR1/AdipoR2 on human peripheral monocytes in patients with unstable vs. stable carotid atherosclerotic plaques. Patients (n=20) with carotid stenosis of ≥50% scheduled for a carotid endarterectomy (CEA) were recruited from the Royal Victoria Hospital, Montreal, Canada. Blood samples were collected the morning of the CEA. A radioimmunoassay was used for plasma total adiponectin measurement. Circulating monocytes were isolated from mononuclear cells using a Magnetic Cell-Sorting technique with CD14+ Human Microbeads. Expression of AdipoR1/AdipoR2 mRNA on peripheral monocytes was determined using quantitative RT-PCR. Carotid plaque specimens were processed for histological analyses. Plaque instability was categorized according to the gold standard American Heart Association classification. All specimens were graded as either a Type V (n=11) or a Type VI plaque (n=9). Type VI represents a more unstable lesion than Type V. AdipoR2 gene expression on monocytes was inversely associated with greater plaque instability; compared to patients with a Type V plaque, those with a Type VI plaque had 1.88-fold decreased AdipoR2 mRNA levels (p=0.046). AdipoR2 gene expression was found to be a trending predictor of a Type VI plaque (OR=2.93; 95% CI=0.87-9.81; p=0.082). AdipoR1 gene expression on monocytes did not differ between the two groups, while plasma adiponectin levels were lower in Type VI plaques (Type VI: 2.73 [2.19-3.96] μg/ml vs. Type V: 6.97 [4.69-10.07] μg/ml; p= 0.067). Plasma adiponectin levels did not correlate with the expression levels of AdipoR1/AdipoR2 on monocytes. These results indicate that carotid plaque instability is associated with decreased AdipoR2 expression on peripheral monocytes. Our ongoing study may determine the underlying mechanisms linking adiponectin and its receptors with plaque instability.

Effects of atrovastatin combined with ezetimibe on carotid atherosclerosis in patients with coronary artery disease

Objective To observe the effects of atorvastatin combined with ezetimibe on carotid atherosclerosis in patients with hypercholesterolemia.Methods A total of 92 hypercholesterolemic patients complicated with coronary artery disease were divided into control group (atorvastatin used alone) and combined treatment group (atorvastatin combined with ezetimibe) and treated for 12 months.Carotid atherosclerosis-related indicators including blood lipid,high-sensitivity C-reactive protein (hs-CRP) and matrix metalloproteinases-9 (MMP-9) were detected before and after treatment.Results After treatment,the plaque area [(19.12 ±2..56) mm2 vs.(23.43 ±2.75)mm2,P ＜0.05],the ratio of unstable carotid atherosclerotic plaques (79.67％ vs.85.84％,P ＜ 0.05),serum level of low density lipoprotein cholesterol (LDL-C)[(2.34±0.56) mm2 vs.(2.75 ±0.58) mmol/L,P＜0.01],MMP-9 [(129.25 ±40.71) μg/L vs.(218.92±60.34) μg/L,P＜0.01] and hs-CRP [(3.18±1.24) mg/L vs.(4.07 ±1.65) mg/L,P＜0.O1] showed significant difference between combined treatment group and control group.The plaque area was decreased significantly in combined treatment group as compared with that before treatment [(19.12 ±2.56) mm2 vs.(25.76± 1.01) mm2,P＜0.05].Conclusion Combination of atorvastatin with ezetimibe could further decrease LDL-C,MMP-9 and hs-CRP levels and have certain effects on the progression of carotid atherosclerosis in hypereholesterolemic patients complicated with coronary artery disease. Key words: Etezimibe ; Atrovastatin; Carotid atherosclerosis

Correlation between aortic/carotid atherosclerotic plaques and cerebral infarction

The aim of this study was to investigate the correlation between aortic/carotid atherosclerotic plaques and cerebral infarction. We examined 116 cases of cerebral infarction using transcranial Doppler ultrasound in order to exclude cerebrovascular stenosis. Transesophageal echocardiography and color Doppler ultrasound were used to detect aortic atherosclerotic plaques (AAPs) and carotid atherosclerotic plaques (CAPs). AAPs were detected in a total of 70 of the 116 cases (60.3%), including 56 with moderate/severe atherosclerotic changes (48.3%). The difference in the incidence of various types of infarction between APP severity levels was significant (P<0.01). Of the 116 cases, 64 had CAPs (55.2%), including 46 with unstable plaque (39.7%). The difference in the incidence of various types of infarction between CAP stability levels was significant (P<0.01). The results indicate that moderate/severe AAP and unstable CAP are significant causes of embolic infarction without stenosis in the internal carotid arteries.

Interleukin-18: a potent pro-inflammatory cytokine in atherosclerosis: EXPERT'S PERSPECTIVE

This editorial refers to an article by R. Elhage et al . [6][1] published in Cardiovascular Research in 2003. It is accompanied by a retrospective editorial by three of the authors of that original article, R. Elhage et al . (doi:10.1093/cvr/cvs220), as part of this Spotlight on Landmark Papers in Cardiovascular Research . The first report on interleukin-18 (IL-18) in patients with myocardial infarction (MI) triggered a significant interest in understanding the role of this cytokine, widely studied in other types of inflammatory diseases, in atherosclerosis.1 Stable and unstable human carotid atherosclerotic plaques were investigated, and it was found that IL-18 was highly expressed compared with control, normal arteries and that it was mainly localized in plaque macrophages.2 IL-18 receptor (IL-18R) was also up-regulated in plaque macrophages and endothelial cells (ECs), suggesting potential biological effects. Significantly higher levels of IL-18 mRNA were found in symptomatic (unstable) plaques as compared with asymptomatic (stable) plaques.2 Electrotransfer of an expression-plasmid DNA encoding murine IL-18-binding protein (BP) in Apo E−/− mice was shown to prevent atherosclerotic plaque progression, inducing changes in plaque composition [a decrease in macrophages, T cells, cell death, and lipid content and an increase in smooth muscle cell (SMC) and collagen content] and leading to a stable plaque phenotype.3 The expression of functional IL-18 and IL-18R was later reported on isolated ECs, SMCs, and macrophages, with the induction of interferon-γ (IFNγ) expression in SMCs.4 Next, studies in Apo E−/− mice showed that IL-18 administration enhanced atherosclerosis in the mouse ascending aorta and the aortic arch through the release of IFNγ.5 However, the IL-18 knockout proof-of-concept was still missing. The effect of blocking the endogenous production of IL18 upon a background of ongoing atherosclerosis progression remained unknown. This information was provided by the important study reported in the … [1]: #ref-6