A B S T R A C TBackground and aims: Unstable carotid atherosclerosis causes stroke, but methods to identify patients and lesions at risk are lacking. We recently found enrichment of genes associated with calcification in carotid plaques from asymptomatic patients. Here, we hypothesized that calcification represents a stabilising feature of plaques and investigated how macro-calcification, as estimated by computed tomography (CT), correlates with gene expression profiles in lesions. Methods: Plaque calcification was measured in pre-operative CT angiographies. Plaques were sorted into high-and lowcalcified, profiled with microarrays, followed by bioinformatic analyses. Immunohistochemistry and qPCR were performed to evaluate the findings in plaques and arteries with medial calcification from chronic kidney disease patients. Results: Smooth muscle cell (SMC) markers were upregulated in high-calcified plaques and calcified plaques from symptomatic patients, whereas macrophage markers were downregulated. The most enriched processes in high-calcified plaques were related to SMCs and extracellular matrix (ECM) organization, while inflammation, lipid transport and chemokine signaling were repressed. These findings were confirmed in arteries with high medial calcification. Proteoglycan 4 (PRG4) was identified as the most upregulated gene in association with plaque calcification and found in the ECM, SMA+ and CD68+/TRAP + cells. Conclusions: Macro-calcification in carotid lesions correlated with a transcriptional profile typical for stable plaques, with altered SMC phenotype and ECM composition and repressed inflammation. PRG4, previously not described in atherosclerosis, was enriched in the calcified ECM and localized to activated macrophages and smooth muscle-like cells. This study strengthens the notion that assessment of calcification may aid evaluation of plaque phenotype and stroke risk.

Objective-Inflammatory responses of large vein endothelium are of importance in pathological processes such as venous thrombosis, chronic venous congestion, and vein graft atherosclerosis. However, the inflammatory properties of large vein endothelium are unclear. Methods and Results-In this study, we used several microscopy techniques to investigate the inflammatory properties of large vein endothelium in vivo. We show that the endothelium in the mouse inferior vena cava (IVC) possesses powerful inflammatory properties that are distinct from the less inflammatory reactive aortic endothelium and virtually identical to endothelial responses in postcapillary venules. Inflammatory stimulation with tumor necrosis factor-␣ induced strong expression of cell adhesion molecules (CAMs) in the IVC. These CAMs promoted recruitment of leukocytes, platelets, and erythrocytes to the vein wall. The inflammatory responses altered endothelial structure and increased endothelial permeability in the IVC. Accumulation of blood cells and endothelial damage were markedly reduced in mice deficient in the endothelial leukocyte recruitment molecules E-selectin and P-selectin, indicating a central role for these molecules in driving structural and functional changes of IVC endothelium. Key Words: endothelium Ⅲ leukocyte Ⅲ rolling Ⅲ adhesion Ⅲ vein Ⅲ inflammation T he vascular endothelium functions as a barrier between tissue and blood and regulates diverse functions such as local and central hemodynamics, exchange of nutrients and metabolites, hemostasis, and immunity. [1][2][3] The endothelium also plays important roles in inflammatory diseases, atherosclerosis, and thrombosis. 4 -7 The endothelial monolayer is a diverse family of cells that, depending on the location in the vascular tree, displays variable responses to a variety of stimuli. For instance, endothelial phenotype in arteries is characterized by the release of substances that influence vascular smooth muscle tone, vessel diameter, and local blood perfusion. 8 Endothelium in postcapillary venules, on the other hand, is specialized at responding to local inflammatory stimuli by increasing its permeability toward macromolecules and by expression of molecules that mediate recruitment of leukocytes to sites of inflammation. 9 The factors that guide endothelial cell phenotype are not fully understood. However, endothelial function is influenced by the developmental origin of the cells as well as by local blood flow dynamics. 10,11 In contrast to the endothelium in arteries and venules, little is known about endothelial function in large veins. Nonetheless, the responses of large vein endothelium play important roles in clinical disease. For example, accumulation of leukocytes on venous endothelium is important in the initial stages of thrombosis. 12 Moreover, destruction of venous valves leading to chronic venous congestion is imposed by inflammatory mechanisms. 13 Furthermore, veins grafted into the arterial circulation in bypass surgery rapidly develop vein graft atherosclero...

Background-Diabetes is an independent risk factor for the development of neointimal hyperplasia and subsequent vein graft failure after coronary or peripheral artery bypass grafting. We evaluate a new mouse model of surgical vein grafting to investigate the mechanisms of neointimal formation in the setting of type 2 diabetes. Methods and Results-Surgical vein grafts were created by inserting vein segments from age-matched C57BL/KsJ wild-type mice into the infra-renal aorta of lepr db/db diabetic and C57BL/KsJ wild-type mice. Mice were euthanized Ϸ4 weeks later, and vein grafts were analyzed using morphometric and immunohistochemical techniques. A significant increase in neointimal formation was noted in lepr db/db mice (139Ϯ64 versus 109Ϯ62 mm 2 ; Pϭ0.008) after 4 weeks. This difference was mainly secondary to an increase in collagen formation within the lesion in the vein grafts from lepr db/db mice (0.53Ϯ0.4 versus 0.44Ϯ0.05; PϽ0.001), whereas only slight increases (Pϭnot significant) in alpha actin-stained smooth muscle cells were noted in the lepr db/db mice. Conclusion-We