M.525 The relation of echogenicity and clinical events to the biochemical composition of human carotid plaques

Background and Aims 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. Methods 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. Results 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. Conclusion 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.

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Abstract 566: The Transcriptome of the Human Carotid Atherosclerotic Plaque

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.33.suppl_1.a566 ◽

2013 ◽

Vol 33 (suppl_1) ◽

Author(s):

Valeriy Poroyko ◽

Susan McCormick ◽

Qi He ◽

Christopher L Skelly

Keyword(s):

Gene Expression ◽

Vulnerable Plaque ◽

Complex Disease ◽

Disease Process ◽

Distance Matrix ◽

Biological Pathways ◽

Cdna Libraries ◽

Carotid Plaques ◽

Whole Transcriptome ◽

Human Carotid

Ischemic stroke is a complex disease process with carotid atherosclerosis as the major etiologic source. To better understand the biology of a vulnerable plaque we carried out whole transcriptome shotgun sequencing of human carotid plaques. Methods 5 carotid atherosclerotic plaques were obtained at the time of operation (2 symptomatic, 2 asymptomatic, and 1 control). RNA was isolated and 5 cDNA libraries were constructed and sequenced with single-reads100nt in length using one line of flow cell of HySeq 2000 (Illumina Inc). Standard bioinformatic techniques were used to ensure quality screening of raw reads. Ingenuity Systems IPA software was used to determine canonical biological pathways overrepresented in plaques. We compared our data to the data of Illumina Human Body Map processed by a similar analytical pipeline. Linkage analysis was performed. Results Among detected pathways were “Atherosclerosis Signaling” and pathways involved in inflammation and cell differentiation. We analyzed gene expression data by creating a distance matrix based on Jaccard similarity measure (Fig 1). When gene expression values were used to create a matrix of Euclidian distances between known transcriptomes, four specimens including the control clustered with heart and muscle. The transcriptome from the stroke patient was more similar to lung, liver and heart. Conclusion Whole transcriptome analysis of carotid plaques is feasible and ontologically accurate. We demonstrate linkage differences between symptomatic and asymptomatic plaques and biological pathways involved in vascular lesion formation. Further analysis may provide insight into the vulnerable plaque pathobiology.

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