Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The beneficial effects of statins in atherosclerosis have been partly attributed to their immunomodulating functions. Dendritic cells (DC), which are "professional" antigen-presenting cells, were recently detected in atherosclerotic plaques. It is assumed that DC play a critical role in the immunological processes related to atherosclerosis. Thus, we investigated the effects of statins on maturation and antigen-presenting function of DC. Human monocyte-derived DC were incubated with simvastatin or atorvastatin (1-10microM) for different periods (1-48h), and were subsequently stimulated with a cytokine cocktail (1.25ng/ml TNF-alpha, 1ng/ml Il-1beta, and 0.5microg/ml prostaglandin E(2)) to induce maturation. In contrast to untreated DC, statin-preincubated DC exhibited an immature phenotype and a significantly lower expression of the maturation-associated markers CD83, CD40, CD86, HLA-DR, and CCR7. The inhibitory statin effect was completely reversed by mevalonate or geranylgeranyl pyrophosphate. In addition, preincubation with statins significantly reduced the ability of cytokine-stimulated DC to induce T cell proliferation. In the present study, we have shown that statins inhibit the maturation and antigen-presenting function of human myeloid dendritic cells, thus maybe contributing to their beneficial effects in atherosclerosis. Therefore, the use of statins as immunomodulators might also provide a new therapeutic approach to other immunological disorders.
Atherosclerosis 2004 Jan
PMID:HMG-CoA reductase inhibitors suppress maturation of human dendritic cells: new implications for atherosclerosis. 1470 61

Atherosclerosis regression is an important clinical goal. In previous studies of regression in mice, the rapid loss of plaque foam cells was explained by emigration to lymph nodes, a process reminiscent of dendritic cells. In the present study, plaque-containing arterial segments from apoE-/- mice were transplanted into WT recipient normolipidemic mice or apoE-/- mice. Three days after transplant, in the WT regression environment, plaque size decreased by approximately 40%, and foam cell content by approximately 75%. In contrast, both parameters increased in apoE-/- recipients. Foam cells were isolated by laser capture microdissection. In WT recipients, there were 3- to 6-fold increases in foam cells of mRNA for liver X receptor alpha and cholesterol efflux factors ABCA1 and SR-BI. Although liver X receptor alpha was induced, there was no detectable expression of its putative activator, peroxisome proliferator-activated receptor gamma. Expression levels of VCAM or MCP-1 were reduced to 25% of levels in pretransplant or apoE-/- recipient samples, but there was induction at the mRNA and protein levels of chemokine receptor CCR7, an essential factor for dendritic cell migration. Remarkably, when CCR7 function was abrogated in vivo by treatment of WT recipients with antibodies to CCR7 ligands CCL19 and CCL21, lesion size and foam cell content were substantially preserved. In summary, in foam cells during atherosclerosis regression, there is induction of CCR7 and a requirement for its function. Taken with the other gene expression data, these results in vivo point to complex relationships among the immune system, nuclear hormone receptors, and inflammation during regression.
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PMID:Gene expression changes in foam cells and the role of chemokine receptor CCR7 during atherosclerosis regression in ApoE-deficient mice. 1653 55

This is a study to define the profile of chemokine receptors expressed on isolated infiltrating lymphocytes in human abdominal aortic aneurysms (AAAs), and to examine their role in lymphoid recruitment. AAA T-lymphocytes were CXCR4-positive, CCR7-negative and partially CXCR3 and CCR5-positive. Functionally, AAA T-cells were proinflammatory effector cells, as they produced IFN-gamma and granzyme A. AAA B-lymphocytes were CXCR4-positive and exhibited low CXCR5 expression. A relevant feature of infiltrating T- and B-lymphocytes was the high intensity of CXCR4 expression and the capability to migrate to CXCL12. CXCL12-producing cells were found in the adventitia of AAA. These cells were CD45-negative and partially VCAM-1 and DR-positive. In summary, the present results suggest that CXCR4, expressed on infiltrating lymphocytes, and CXCL12, expressed on stromal cells, is involved in the recruitment of lymphocytes within the arterial wall in AAA.
Atherosclerosis 2008 Oct
PMID:Chemokine receptor expression on infiltrating lymphocytes from abdominal aortic aneurysms: role of CXCR4-CXCL12 in lymphoid recruitment. 1828 Oct 50

Research suggests that monocytes differentiate into unique lineage-determined macrophage subpopulations in response to the local cytokine environment. The present study evaluated the atherogenic potential of two divergent lineage-determined human monocyte-derived macrophage subpopulations. Monocytes were differentiated for 7 days in the presence of alternative macrophage development cytokines: granulocyte-macrophage colony-stimulating factor to produce granulocyte-macrophage-CSF macrophages (GM-Mac), or macrophage colony-stimulating factor (M-CSF) to produce M-Mac. Gene chip analyses of three monocyte donors demonstrated differential expression of inflammatory and cholesterol homeostasis genes in the macrophage subpopulations. Quantitative PCR confirmed a fivefold elevation in the expression of genes that promote reverse cholesterol transport (PPAR-gamma, LXR-alpha, and ABCG1) and macrophage emigration from lesions (CCR7) in GM-Mac compared to that in M-Mac. Immunocytochemistry confirmed enhanced expression of the proinflammatory marker CD14 in M-Mac relative to GM-Mac. M-Mac spontaneously accumulated cholesterol when incubated with unmodified low-density lipoprotein whereas GM-Mac only accumulated similar levels of cholesterol after protein kinase C activation. Immunostained human coronary arteries showed that macrophages with similar antigen expression to that of M-Mac (CD68(+)/CD14(+)) were predominant within atherosclerotic lesions whereas macrophages with antigen expression similar to GM-Mac (CD68(+)/CD14(-)) were predominant in areas devoid of disease. The identification of macrophage subpopulations with different gene expression patterns and, thus, different potentials for promoting atherosclerosis has important experimental and clinical implications and could prove to be a valuable finding in developing therapeutic interventions in diseases dependent on macrophage function.
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PMID:Heterogeneity of human macrophages in culture and in atherosclerotic plaques. 1832 97

Atherosclerosis is the leading cause of death worldwide. To date, the use of statins to lower LDL levels has been the major intervention used to delay or halt disease progression. These drugs have an incomplete impact on plaque burden and risk, however, as evidenced by the substantial rates of myocardial infarctions that occur in large-scale clinical trials of statins. Thus, it is hoped that by understanding the factors that lead to plaque regression, better approaches to treating atherosclerosis may be developed. A transplantation-based mouse model of atherosclerosis regression has been developed by allowing plaques to form in a model of human atherosclerosis, the apoE-deficient mouse, and then placing these plaques into recipient mice with a normolipidemic plasma environment. Under these conditions, the depletion of foam cells occurs. Interestingly, the disappearance of foam cells was primarily due to migration in a CCR7-dependent manner to regional and systemic lymph nodes after 3 days in the normolipidemic (regression) environment. Further studies using this transplant model demonstrated that liver X receptor and HDL are other factors likely to be involved in plaque regression. In conclusion, through the use of this transplant model, the process of uncovering the pathways regulating atherosclerosis regression has begun, which will ultimately lead to the identification of new therapeutic targets.
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PMID:The role of a murine transplantation model of atherosclerosis regression in drug discovery. 1933 80

Cariogenic and periodontal pathogens are thought to be etiological factors in the development of cardiovascular disease. We assessed the involvement of the periodontal pathogen Aggregatibacter actinomycetemcomitans and cariogenic pathogen Streptococcus mutans in the development of atherosclerosis in apolipoprotein E-deficient spontaneously hyperlipidemic (Apoe(shl)) mice. The mice were treated intravenously with A. actinomycetemcomitans HK1651, S. mutans GS-5, or phosphate-buffered saline three times a week for 3 weeks and killed at 15 weeks of age. The areas of the aortic sinus that were covered with atherosclerotic plaque were significantly larger in Apoe(shl) mice challenged with A. actinomycetemcomitans compared with S. mutans- or vehicle-challenged mice. Aggregatibacter actinomycetemcomitans challenge increased serum high-sensitive C-reactive protein and lipopolysaccharide levels. Bacterial DNA was detected in the blood, heart, and spleen, but not in the liver. Furthermore, serum interleukin-6 (IL-6), IL-8, tumor necrosis factor alpha, and MCP-1 levels and Toll-like receptor (TLR)2, TLR4, ICAM-1, E-selectin, P-selectin, LOX-1, HSP60, CCL19, CCL21, CCR7, and MCP-1 expressions in the aorta were significantly increased in mice challenged with A. actinomycetemcomitans. These results suggest that systemic infection with A. actinomycetemcomitans accelerates atherosclerosis in Apoe(shl) mice by exposing the whole microorganisms or their products, followed by initiating inflammation. Increases in proatherogenic factors may explain the aggravation of atherosclerosis by A. actinomycetemcomitans infection.
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PMID:Aggregatibacter actinomycetemcomitans accelerates atherosclerosis with an increase in atherogenic factors in spontaneously hyperlipidemic mice. 2048 27

We have previously shown that mouse atherosclerosis regression involves monocyte-derived (CD68+) cell emigration from plaques and is dependent on the chemokine receptor CCR7. Concurrent with regression, mRNA levels of the gene encoding LXRalpha are increased in plaque CD68+ cells, suggestive of a functional relationship between LXR and CCR7. To extend these results, atherosclerotic Apoe-/- mice sufficient or deficient in CCR7 were treated with an LXR agonist, resulting in a CCR7-dependent decrease in plaque CD68+ cells. To test the requirement for LXR for CCR7-dependent regression, we transplanted aortic arches from atherosclerotic Apoe-/- mice, or from Apoe-/- mice with BM deficiency of LXRalpha or LXRbeta, into WT recipients. Plaques from both LXRalpha and LXRbeta-deficient Apoe-/- mice exhibited impaired regression. In addition, the CD68+ cells displayed reduced emigration and CCR7 expression. Using an immature DC line, we found that LXR agonist treatment increased Ccr7 mRNA levels. This increase was blunted when LXRalpha and LXRbeta levels were reduced by siRNAs. Moreover, LXR agonist treatment of primary human immature DCs resulted in functionally significant upregulation of CCR7. We conclude that LXR is required for maximal effects on plaque CD68+ cell expression of CCR7 and monocyte-derived cell egress during atherosclerosis regression in mice.
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PMID:LXR promotes the maximal egress of monocyte-derived cells from mouse aortic plaques during atherosclerosis regression. 2104 49

HDL cholesterol (HDL-C) plasma levels are inversely related to cardiovascular disease risk. Previous studies have shown in animals and humans that HDL promotes regression of atherosclerosis. We hypothesized that this was related to an ability to promote the loss of monocyte-derived cells (CD68(+), primarily macrophages and macrophage foam cells) from plaques. To test this hypothesis, we used an established model of atherosclerosis regression in which plaque-bearing aortic arches from apolipoprotein E-deficient (apoE(-/-)) mice (low HDL-C, high non-HDL-C) were transplanted into recipient mice with differing levels of HDL-C and non-HDL-C: C57BL6 mice (normal HDL-C, low non-HDL-C), apoAI(-/-) mice (low HDL-C, low non-HDL-C), or apoE(-/-) mice transgenic for human apoAI (hAI/apoE(-/-); normal HDL-C, high non-HDL-C). Remarkably, despite persistent elevated non-HDL-C in hAI/apoE(-/-) recipients, plaque CD68(+) cell content decreased by >50% by 1 wk after transplantation, whereas there was little change in apoAI(-/-) recipient mice despite hypolipidemia. The decreased content of plaque CD68(+) cells after HDL-C normalization was associated with their emigration and induction of their chemokine receptor CCR7. Furthermore, in CD68(+) cells laser-captured from the plaques, normalization of HDL-C led to decreased expression of inflammatory factors and enrichment of markers of the M2 (tissue repair) macrophage state. Again, none of these beneficial changes were observed in the apoAI(-/-) recipients, suggesting a major requirement for reverse cholesterol transport for the beneficial effects of HDL. Overall, these results establish HDL as a regulator in vivo of the migratory and inflammatory properties of monocyte-derived cells in mouse atherosclerotic plaques, and highlight the phenotypic plasticity of these cells.
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PMID:HDL promotes rapid atherosclerosis regression in mice and alters inflammatory properties of plaque monocyte-derived cells. 2148 81

Experimental models of atherosclerosis suggest that recruitment of monocytes into plaques drives the progression of this chronic inflammatory condition. Cholesterol-lowering therapy leads to plaque stabilization or regression in human atherosclerosis, characterized by reduced macrophage content, but the mechanisms that underlie this reduction are incompletely understood. Mice lacking the gene Apoe (Apoe-/- mice) have high levels of cholesterol and spontaneously develop atherosclerotic lesions. Here, we treated Apoe-/- mice with apoE-encoding adenoviral vectors that induce plaque regression, and investigated whether macrophage removal from plaques during this regression resulted from quantitative alterations in the ability of monocytes to either enter or exit plaques. Within 2 days after apoE complementation, plasma cholesterol was normalized to wild-type levels, and HDL levels were increased 4-fold. Oil red O staining and quantitative mass spectroscopy revealed that esterified cholesterol content was markedly reduced. Plaque macrophage content decreased gradually and was 72% lower than baseline 4 weeks after apoE complementation. Importantly, this reduction in macrophages did not involve migratory egress from plaques or CCR7, a mediator of leukocyte emigration. Instead, marked suppression of monocyte recruitment coupled with a stable rate of apoptosis accounted for loss of plaque macrophages. These data suggest that therapies to inhibit monocyte recruitment to plaques may constitute a more viable strategy to reduce plaque macrophage burden than attempts to promote migratory egress.
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PMID:Suppressed monocyte recruitment drives macrophage removal from atherosclerotic plaques of Apoe-/- mice during disease regression. 2150 65

HMG-CoA reductase inhibitors (statins) decrease atherosclerosis by lowering low-density-lipoprotein cholesterol. Statins are also thought to have additional anti-atherogenic properties, yet defining these non-conventional modes of statin action remains incomplete. We have previously developed a novel mouse transplant model of atherosclerosis regression in which aortic segments from diseased donors are placed into normolipidemic recipients. With this model, we demonstrated the rapid loss of CD68+ cells (mainly macrophages) in plaques through the induction of a chemokine receptor CCR7-dependent emigration process. Because the human and mouse CCR7 promoter contain Sterol Response Elements (SREs), we hypothesized that Sterol Regulatory Element Binding Proteins (SREBPs) are involved in increasing CCR7 expression and through this mechanism, statins would promote CD68+ cell emigration from plaques. We examined whether statin activation of the SREBP pathway in vivo would induce CCR7 expression and promote macrophage emigration from plaques. We found that western diet-fed apoE(-/-) mice treated with either atorvastatin or rosuvastatin led to a substantial reduction in the CD68+ cell content in the plaques despite continued hyperlipidemia. We also observed a significant increase in CCR7 mRNA in CD68+ cells from both the atorvastatin and rosuvastatin treated mice associated with emigration of CD68+ cells from plaques. Importantly, CCR7(-/-)/apoE(-/-) double knockout mice failed to display a reduction in CD68+ cell content upon statin treatment. Statins also affected the recruitment of transcriptional regulatory proteins and the organization of the chromatin at the CCR7 promoter to increase the transcriptional activity. Statins promote the beneficial remodeling of plaques in diseased mouse arteries through the stimulation of the CCR7 emigration pathway in macrophages. Therefore, statins may exhibit some of their clinical benefits by not only retarding the progression of atherosclerosis, but also accelerating its regression.
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PMID:Statins promote the regression of atherosclerosis via activation of the CCR7-dependent emigration pathway in macrophages. 2216 30


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