UMLS:C0004153 - FACTA Search

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Query: UMLS:C0004153 (atherosclerosis)
77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The association of autoimmune phenomena with atherosclerosis suggests that plaques may contain specialized antigen-presenting cells, dendritic cells (DCs). DC-SIGN is a C-type lectin expressed by DCs. This study assessed whether human atherosclerotic plaques expressed DC-SIGN and several other macrophage/DC markers. Plaques from human coronary and carotid arteries and aorta contained DC-SIGN-immunoreactive cells. Double-labelling showed co-expression of DC-SIGN and macrophage/DC lineage markers CD14, CD68, HLA-DR, and S100. There was no immunoreactivity for the DC activation markers CD83 or CMRF-44. Since DC-SIGN mediates adhesion to T-lymphocytes and endocytosis, its expression in atherosclerotic plaques may have functional implications. Activated DCs migrate quickly from areas of inflammation to regional lymph nodes, possibly explaining the paucity of activated DCs in atherosclerotic plaques. In conclusion, this study has shown that DC-SIGN is expressed in atherosclerosis.
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PMID:Human atherosclerotic plaques express DC-SIGN, a novel protein found on dendritic cells and macrophages. 1243 21

Recent studies have suggested that Chlamydia pneumoniae infection is an important factor in the development of atherosclerosis. The C(-260)-->T polymorphism in the CD14 promoter gene has been reported to regulate the density of CD14 expression on monocytes for the activation of monocytes to secrete inflammatory cytokines by lipopolysaccharide. We investigated this genetic marker and its association with C. pneumoniae infection. Among 315 healthy subjects, the distribution of the C(-260)-->T polymorphism in the CD14 promoter gene was 14.9% for the CC genotype, 54.3% for the CT genotype, and 30.8% for the TT genotype. Among subjects with the 3 CD14 genotypes, 59.5%, 64.9%, and 78.3%, respectively, were seropositive for C. pneumoniae. With multiple logistic regression analysis, the odds ratio of C. pneumoniae infection was 2.08 for CD14 TT genotype (95% confidence interval, 1.18-3.69; P=.016). A significant association between the CD14 TT genotype and C. pneumoniae infection was found.
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PMID:Association of CD14 promoter gene polymorphism and Chlamydia pneumoniae infection. 1282 76

Both inflammation and genetics play an important role in the pathogenesis of atherosclerosis and coronary artery disease. Epidemiological studies have investigated the association between coronary artery disease (CAD) and gene polymorphisms of the inflammatory molecules tumor necrosis factors (TNF) alpha and beta, transforming growth factors (TGF) beta-1 and beta-2, interleukin (IL)-1 and its receptor antagonist (IL-1ra), CD14 (the receptor for lipopolysaccharide), P- and E-selectins, and platelet endothelial cell adhesion molecule (PECAM)-1. Current evidence suggests that the TNF polymorphisms explored so far are not linked to CAD. The majority of studies conducted showed no significant association between TGFbeta-1 and coronary atherosclerosis, but the data currently available are somewhat controversial. Some polymorphisms may increase the risk of myocardial infarction (MI) within specific ethnic groups or in certain populations. The association between the IL-1 system and atherosclerosis is complex and may vary as a result of a number of factors, such as stage of disease, clinical phenotype, and possibly population characteristics. The E-selectin gene (SELE) Arg128, 98T, and Phe554 alleles may increase the risk of atherosclerosis, but not necessarily the risk of MI. This association seems to be more pronounced in younger patients. The PECAM1 Leu125Val and Ser563Asn polymorphisms may increase the risk of atherosclerosis but not necessarily of MI. This association may be especially important in patients with a low risk for developing atherosclerosis. Current data indicate that screening for CD14-260C/T genotypes is unlikely to be a useful tool for risk assessment and it remains unclear whether CD14 polymorphisms significantly increase the risk of MI. The associations between candidate gene polymorphisms and CAD are complex as a consequence of pleiotropy, variations with age, selection due to the high lethality of the disease, and interactions with other genes and environmental factors. Nonetheless, although the current data is preliminary and partly conflicting, it does provide some evidence that alterations in the genetics of the inflammatory system may modify the risk of CAD.
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PMID:Genetic polymorphisms in cytokine and adhesion molecule genes in coronary artery disease. 1457 20

Atherosclerosis, the leading cause of death in developed countries, has been linked to hypercholesterolemia for decades. More recently, atherosclerotic lesion progression has been shown to depend on persistent, chronic inflammation in the artery wall. Although several studies have implicated infectious agents in this process, the role of infection in atherosclerosis remains controversial. Because the involvement of monocytes and macrophages in the pathogenesis of atherosclerosis is well established, we investigated the possibility that macrophage innate immunity signaling pathways normally activated by pathogens might also be activated in response to hyperlipidemia. We examined atherosclerotic lesion development in uninfected, hyperlipidemic mice lacking expression of either lipopolysaccharide (LPS) receptor CD14 or myeloid differentiation protein-88 (MyD88), which transduces cell signaling events downstream of the Toll-like receptors (TLRs), as well as receptors for interleukin-1 (IL-1) and IL-18. Whereas the MyD88-deficient mice evinced a marked reduction in early atherosclerosis, mice deficient in CD14 had no decrease in early lesion development. Inactivation of the MyD88 pathway led to a reduction in atherosclerosis through a decrease in macrophage recruitment to the artery wall that was associated with reduced chemokine levels. These findings link elevated serum lipid levels to a proinflammatory signaling cascade that is also engaged by microbial pathogens.
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PMID:Reduced atherosclerosis in MyD88-null mice links elevated serum cholesterol levels to activation of innate immunity signaling pathways. 1503 66

Atherosclerosis is at least in part an inflammatory disease. CD14 is an endotoxin receptor that after binding of lipopolysaccharides evokes endothelial activation and secretion of several cytokines. A polymorphism of CD14 has been associated with myocardial infarction. We evaluated the role of the -159 T/C polymorphism in the promoter region of the CD14 gene in relation to severity and progression of coronary atherosclerosis and response to the HMG CoA reductase inhibitor pravastatin. We recruited patients from the multi-center double-blind randomized placebo controlled REGRESS trial and genotyped the -159T/C CD14 polymorphism. DNA and angiographic follow-up were available from 759 patients with objectivated coronary artery disease. We measured changes in mean segment diameter (MSD) and minimum obstruction diameter (MOD) with quantitative coronary angiography and noted the occurrence of major adverse cardiac events. The genotype distribution was 28% TT, 49% CT, 23% CC. We did not find any association between genotype and MSD and MOD at baseline, frequency of previous myocardial infarction, changes in MSD and MOD or major clinical events. Treatment with the HMG CoA reductase inhibitor pravastatin reduced progression of coronary atherosclerosis and adverse events equally for all genotypes. We conclude, that the -159T/C polymorphism in the CD14 monocyte receptor gene was not associated with progression of coronary atherosclerosis in this population nor did it influence the efficacy of pravastatin in the treatment of atherosclerosis.
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PMID:Pharmacogenetics of the CD14 endotoxin receptor polymorphism and progression of coronary atherosclerosis. 1511 60

Endothelial cells are activated by microbial agonists through Toll-like receptors (TLRs) to express inflammatory mediators; this is of significance in acute as well as chronic inflammatory states such as septic shock and atherosclerosis, respectively. We investigated mechanisms of lipopolysaccharide (LPS)-induced cell activation in human coronary artery endothelial cells (HCAEC) using a combination of FACS, confocal microscopy, RT-PCR, and functional assays. We found that TLR4, in contrast to TLR2, is not only located intracellularly but also functions intracellularly. That being the case, internalization of LPS is required for activation. We further characterized the HCAEC LPS uptake system and found that HCAEC exhibit an effective LPS uptake only in the presence of LPS binding protein (LBP). In addition to its function as a catalyst for LPS-CD14 complex formation, LBP enables HCAEC activation at low LPS concentrations by facilitating the uptake, and therefore delivery, of LPS-CD14 complexes to intracellular TLR4-MD-2. LBP-dependent uptake involves a scavenger receptor pathway. Our findings may be of pathophysiological relevance in the initial response of the organism to infection. Results further suggest that LBP levels, which vary as LBP is an acute phase reactant, could be relevant to initiating inflammatory responses in the vasculature in response to chronic or recurring low LPS.
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PMID:Toll-like receptor 4 functions intracellularly in human coronary artery endothelial cells: roles of LBP and sCD14 in mediating LPS responses. 1513 88

Pistacia lentiscus var. Chia (Anacardiaceae) grows almost exclusively on Chios Island, Greece, and gives a resinous exudate resin used for culinary purposes by Mediterranean people. We investigated the molecular mechanisms through which total polar extract of the resin inhibits oxidized low-density lipoprotein (oxLDL) cytotoxic effect on peripheral blood mononuclear cell (PBMC). Cells exposed to oxLDL underwent apoptosis and necrosis, dependent on the duration of exposure. When culturing cells with oxLDL and the polar extract concurrently, we observed inhibition of both the phenomena. Because under oxidative stress the pro-oxidant systems outbalance the antioxidant, potentially producing oxidative damage and ultimately leading to cell death, we measured the levels of intracellular antioxidant glutathione (GSH). Additionally, we measured CD36 expression, a class B scavenger receptor, on CD14-positive cells, as CD36 has been identified as the oxLDL receptor in macrophages and may play a pivotal role in atherosclerotic foam cell formation. oxLDL decreased GSH levels and upregulated CD36 expression. P. lentiscus extract restored GSH levels and downregulated CD36 expression, even at the mRNA level. In order to find out the biologically drastic constituents of the resin's polar extract, fractions derived from RP-HPLC analysis were examined for their antioxidant effect on oxidatively stressed PBMC. The triterpenoid fraction revealed remarkable increase in intracellular GSH. We suggest GSH restoration and downregulation of CD36 mRNA expression as the pathways via which P. lentiscus triterpenes exert antioxidant/antiatherogenic effect. Additionally, our results provide strong evidence of the resin's antiatherogenic effect; therefore it is credited with beneficial health aspects.
Atherosclerosis 2004 Jun
PMID:Antiatherogenic effect of Pistacia lentiscus via GSH restoration and downregulation of CD36 mRNA expression. 1513 59

Toll-like receptors (TLRs) and other pattern-recognition receptors (PRRs) of the innate immune system form functional receptor complexes that recognize and respond to pathogen-associated molecular patterns (PAMPs). Porphyromonas gingivalis is an important pathogen in human periodontitis and has also been implicated in atherosclerosis. A major virulence factor of this pathogen is the fimbriae, which function as a surface adhesin. Here we present evidence that fimbriae also constitute a predominant P. gingivalis proinflammatory molecule which activates the TLR signaling pathway resulting in induction of proinflammatory cytokines (IL-1beta, IL-6, and TNF-alpha) and chemokines (IL-8) in monocytic cells. Although TLR2 and TLR4 mediate cellular activation in response to fimbriae, other PRRs, namely CD14 and CD11b/CD18, are involved in the recognition of fimbriae. We thus propose that fimbriae function as a PAMP which interacts with a PRR multi-receptor complex, where CD14 and CD11b/CD18 function as recruiting receptors and TLRs function as signaling receptors. In addition to cytokine induction, TLR activation by fimbriae also results in upregulation of the CD40, CD80, and CD86 costimulatory molecules in antigen-presenting cells, suggesting that fimbriae are sensed as a potential "danger" to the host immune system. Moreover, proinflammatory cytokine induction is attenuated upon repeated cellular stimulation with P. gingivalis fimbriae. This mechanism of tolerance induction which serves to mitigate excessive and potentially harmful inflammatory reactions appears to be due partly to fimbria-induced downregulation of the expression of interleukin-1 receptor-associated kinase-1 (IRAK-1), an important signaling intermediate of the TLR pathway. Understanding the molecular basis of how the host recognizes and responds to P. gingivalis fimbriae is essential for developing molecular approaches to control P. gingivalis-induced inflammatory responses in periodontal disease and perhaps atherosclerosis.
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PMID:Intracellular signaling and cytokine induction upon interactions of Porphyromonas gingivalis fimbriae with pattern-recognition receptors. 1519 95

Chlamydia pneumoniae, a respiratory pathogen implicated in the development and progress of atherosclerosis, is known to infect and survive in macrophages, despite macrophage producing reactive oxygen species (ROS). To gain insight into ROS generation in macrophages infected with C. pneumoniae and to explore factors accounting for their final levels and effect, we investigated the role of NADPH oxidase and cytochrome oxidase pathways in the production and modulation of ROS. We also determined the operational role of Ca2+ signaling in the process. Macrophages stimulated with C. pneumoniae exhibit early release of ROS via up-regulation of NADPH oxidase and cytochrome c oxidase activities. Increasing the dose of C. pneumoniae led to an increase in the expression of these enzymes gene production, which was accompanied by a significant up-regulation of their gene products, implying a probable activation of transcriptional and translational processes, respectively. The change in levels of free Ca2+, influx across plasma membrane and efflux from intracellular store into cytosol all exhibited a significant regulatory role on the ROS generation pathways in macrophages. The observed events were shown to be dependent on binding of C. pneumoniae to CD14 receptors of macrophages. The data reported here imply that macrophages infected with C. pneumoniae produce ROS through membrane-associated NADPH oxidase with oxidative phosphorylation levels depending on Ca2+ influx signals.
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PMID:Elicitation of reactive oxygen species in Chlamydia pneumoniae-stimulated macrophages: a Ca2+-dependent process involving simultaneous activation of NADPH oxidase and cytochrome oxidase genes. 1519 88

Low-level endotoxemia has been identified as a powerful risk factor for atherosclerosis. However, little is known about the mechanisms that regulate endotoxin responsiveness in vascular cells. We conducted experiments to compare the relative responses of human coronary artery endothelial cells (HCAEC) and smooth muscle cells (HCASMC) to very low levels of endotoxin, and to elucidate the mechanisms that regulate endotoxin responsiveness in vascular cells. Endotoxin (</=1 ng/ml) caused production of chemotactic cytokines in HCAEC. Endotoxin-induced cytokine production was maximal at LPS-binding protein:soluble CD14 ratios <1, typically observed in individuals with subclinical infection; higher LPS-binding protein:soluble CD14 ratios were inhibitory. Endotoxin potently activated HCASMC, with cytokine release >10-fold higher in magnitude at >10-fold lower threshold concentrations (10-30 pg/ml) compared with HCAEC. This remarkable sensitivity of HCASMC to very low endotoxin concentrations, comparable to that found in circulating monocytes, was not due to differential expression of TLR4, which was detected in HCAEC, HCASMC, and intact coronary arteries. Surprisingly, membrane-bound CD14 was detected in seven different lines of HCASMC, conferring responsiveness to endotoxin and to lipoteichoic acid, a product of Gram-positive bacteria, in these cells. These results suggest that the low levels of endotoxin associated with increased risk for atherosclerosis are sufficient to produce inflammatory responses in coronary artery cells. Because CD14 recognizes a diverse array of inflammatory mediators and functions as a pattern recognition molecule in inflammatory cells, expression of membrane-bound CD14 in HCASMC implies a potentially broader role for these cells in transducing innate immune responses in the vasculature.
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PMID:Regulation of endotoxin-induced proinflammatory activation in human coronary artery cells: expression of functional membrane-bound CD14 by human coronary artery smooth muscle cells. 1524 Jul 28

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