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)

Familial hypercholesterolemia (FH) is a monogenic disorder associated with primary hypercholesterolemia. FH is characterized by autosomal co-dominant inheritance with strikingly elevated LDL-cholesterol, the presence of xanthoma and premature atherosclerosis. In the course of investigations of coronary artery disease in Utah, we identified a family whose proband showed elevated plasma levels of LDL cholesterol. To determine the genetic etiology of the lipoprotein abnormalities, we screened DNA samples from the family for mutations in all 18 exons and the exon- intron boundaries of the low-density lipoprotein receptor (LDLR) gene. Novel point mutations were identified in the proband: a one-base insertion of G to a five-G stretch at nucleotides 2412-6 (codons 783-785), causing a frameshift in exon 17 of the LDL receptor gene. The direct sequencing method was used to examine six members of the family recruited for the diagnosis. This method helped to unequivocally diagnose the five individuals as heterozygous for this particular LDL receptor mutation. This method also helped us to diagnose with FH, or to exclude from carrier status, three children between ages 6 and 11.
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PMID:Familial hypercholesterolemia in Utah kindred with novel 2412-6 Ins G mutations in exon 17 of the LDL receptor gene. 1061 8

Although age is a strong risk factor for atherosclerosis, it is unclear whether age may directly influence the process of atherogenesis. We, therefore, performed several studies in young (2-4 months old), mature (10-14 months old), and old (20-22 months old) mice to determine if the rate of aortic lesion formation increases with age, and whether this is related to increases in oxidative stress or vascular cell adhesion molecule (VCAM-1) expression in the aortic wall. In chow-fed low-density lipoprotein receptor-deficient (LDLR-/-) mice, plasma total cholesterol levels increased with age (250 +/- 52 mg/dl in young, 276 +/- 58 in mature, and 314 +/- 101 mg/dl in old mice). In contrast, the extent of atherosclerosis rose more rapidly, increasing from 3.6 +/- 2.7% of the aortic surface in mature mice to 18.2 +/- 8% in old mice. Plasma and tissue levels of antioxidant enzymes and molecules, as well as plasma thiobarbituric acid reactive substances and low-density lipoprotein susceptibility to oxidation, did not change with age. In a second study, VCAM-1 expression in the aortic arch and the extent of atherosclerosis in the aortic origin were significantly greater in old LDLR-/- mice than in young LDLR-/- mice. Additionally, after 1 month of a high-fat diet, which induced equally elevated plasma cholesterol levels in both young and old LDLR-/- mice, VCAM-1 expression and aortic lesion formation were still greater in old mice. The extent of atherosclerosis correlated well (r = .65,p <.01) with the expression of VCAM-1 in the aortic origin. In a final study, we measured VCAM-1 expression and atherosclerosis in young, mature, and old C57BL/6 mice, which have low plasma cholesterol levels (< or =100 mg/dl) when fed a standard chow diet. Although plasma cholesterol levels did not increase with age, old C57BL/6 mice had significantly more VCAM-1 expression in the aortic arch than did young mice. However, no lesions were observed in the aortic origin in either group. These data demonstrate that plasma cholesterol levels and VCAM-1 expression increase with age and suggest that this may contribute to the increased rate of atherosclerotic lesion formation in LDLR-/- mice. Importantly, the age-dependent increase in VCAM-1 expression does not appear to be related to plasma cholesterol levels. This study also suggests that in the absence of elevated plasma cholesterol, an increased expression of VCAM-1 alone is not sufficient for lesion formation.
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PMID:Effect of aging on aortic expression of the vascular cell adhesion molecule-1 and atherosclerosis in murine models of atherosclerosis. 1073 83

Interruption of inflammatory pathways may provide a novel approach to the therapy of atherosclerosis. Recently, we and others have implicated the immune mediator dyad CD40/CD40L (CD40 ligand), which is expressed on endothelial and smooth muscle cells, macrophages, and T lymphocytes within human atherosclerotic lesions, in aspects of atherogenesis and the acute coronary syndromes, including regulation of matrix metalloproteinases, procoagulant activity, cytokines, etc. In vivo, interruption of CD40 signaling reduced the initiation and early phases of atheroma formation in hypercholesterolemic mice. However, whether interruption of CD40 signaling can retard the progression or even regress established lesions remains unknown. We report here that anti-CD40L antibody treatment of randomly assigned low-density lipoprotein receptor-deficient mice during the second half of a 26-week regimen of high-cholesterol diet did not regress, but did significantly reduce further evolution of established atherosclerotic lesions within the aortic arch and particularly the thoracic and abdominal aorta, as compared with control treatment (application of rat-IgG or saline; 13 weeks, continued high-cholesterol diet). In addition to limiting lesion progression, anti-CD40L treatment changed the composition of atheroma in manners thought to favor plaque stability, e.g., reduced relative content of macrophages and lipid, as well as increased relative content of smooth muscle cells and collagen. These data implicate CD40/CD40L as crucial mediators not only in the initial events of atherogenesis but also during the evolution of established atheroma. This study lends further support to the importance of this specific inflammatory signaling pathway in atherosclerosis and its complications.
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PMID:Inhibition of CD40 signaling limits evolution of established atherosclerosis in mice. 1086 Sep 49

Several in vivo studies have been performed on the role of the macrophage scavenger receptor class A (SR-A) in atherosclerosis using SR-A knockout mice. The results indicate both an antiatherogenic and a proatherogenic role of SR-A, depending on the nature of the animal model serving as the athero-susceptible background. To study the role of SR-A in a different model, we generated a transgenic mouse model with high level expression of the human SR-A gene using a 180 Kb yeast artificial chromosome (MSR1 transgenic mice). These mice show increased expression of SR-A according to the natural expression pattern. The MSR1 transgenic mice were crossed onto a low-density lipoprotein receptor deficient background and were fed a high fat diet for 10 weeks. After this period, the size of the atherosclerotic lesions in the proximal aorta was measured. Surprisingly, atherosclerosis was significantly reduced in the MSR1 transgenic mice. In a second study, the effect of SR-A was examined in APOE-3 Leiden mice providing a different athero-susceptible background. To exclude nonmacrophage effects, bone marrow was transplanted from MSR1 mice and wild-type littermates to APOE-3 Leiden transgenic mice. After 8 weeks on a high fat diet, atherosclerosis in the mice that had received MSR1 bone marrow was reduced compared with mice that had received wild-type bone marrow. This difference reached statistical significance when individual cholesterol exposure of the mice was taken into account. Both experiments indicated an antiatherogenic role of the SR-A. This observation cannot be explained easily by SR-A function in foam cell formation because in MSR1 macrophages in vitro foam cell formation is increased. Alternatively, however, SR-A may affect the activation of macrophages. Hence the response to lipopolysaccharide was measured in MSR1-transgenic macrophages. These macrophages showed a reduction in their activation in response to lipopolysaccharide, as measured by nitric oxide production. These data show that an elevated level of SR-A expression reduces atherosclerosis, potentially by modifying the response of macrophages to activation signals in the plaque.
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PMID:Transgenic mouse models to study the role of the macrophage scavenger receptor class A in atherosclerosis. 1093 58

The aim of this study was to detect mutations in the genes coding for the low-density lipoprotein receptor and apolipoprotein B in patients of Southeast Asian origin with clinically diagnosed familial hypercholesterolemia (FH) and to relate these findings with the observed lower incidence of coronary heart disease in this part of the world. A total of 86 unrelated patients with FH were selected on clinical grounds, and complete DNA analysis of the low-density lipoprotein (LDL)-receptor and apolipoprotein B (apoB) genes by DGGE and DNA-sequencing was performed. In the majority (73%) of the cohort studied, no mutations could be detected, even after extensive analysis of the LDL-receptor and apoB genes. However, the 22 patients with a mutation had significantly more xanthomas and a higher incidence of coronary heart disease and levels of low-density lipoproteins were also significantly different. There was no correlation between the type of the mutation and lipoprotein levels or clinical signs of atherosclerosis. The fact that the majority of the FH patients studied had no detectable mutation and that this group had a significant milder phenotype, suggests the presence of a third gene in the Southeast Asian population, predominantly leading to a disorder resembling a milder form of FH. A similar, but less frequent, trait has recently been described in a number of European families.
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PMID:Low-density lipoprotein receptor gene mutations in a Southeast Asian population with familial hypercholesterolemia. 1100 41

Thromboxane A(2) is a potent vasoconstrictor and platelet agonist; prostacyclin is a potent platelet inhibitor and vasodilator. Altered biosynthesis of these eicosanoids is a feature of human hypercholesterolemia and atherosclerosis. This study examined whether in 2 murine models of atherosclerosis their levels are increased and correlated with the evolution of the disease. Urinary 2,3-dinor thromboxane B(2) and 2,3-dinor-6-keto prostaglandin F(1 alpha), metabolites of thromboxane and prostacyclin, respectively, were assayed in apoliprotein E (apoE)-deficient mice on chow and low-density lipoprotein receptor (LDLR)-deficient mice on chow and a Western-type diet. Atherosclerosis lesion area was measured by en face method. Both eicosanoids increased in apoE-deficient mice on chow and in LDLR-deficient mice on a high-fat diet, but not in LDLR-deficient mice on chow by the end of the study. Aspirin suppressed ex vivo platelet aggregation, serum thromboxane B(2), and 2,3-dinor thromboxane B(2), and significantly reduced the excretion of 2,3-dinor-6-keto prostaglandin F(1 alpha) in these animals. This study demonstrates that thromboxane as well as prostacyclin biosynthesis is increased in 2 murine models of atherogenesis and is secondary to increased in vivo platelet activation. Assessment of their generation in these models may afford the basis for future studies on the functional role of these eicosanoids in the evolution and progression of atherosclerosis. (Blood. 2000;96:3823-3826)
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PMID:Endogenous biosynthesis of thromboxane and prostacyclin in 2 distinct murine models of atherosclerosis. 1109 66

Apolipoprotein E (ApoE) plays a pivotal role in the metabolism of apolipoprotein B (apoB)-containing lipoproteins. The defective apoE gene in humans can cause elevated plasma levels of apoB-containing lipoproteins such as chylomicron remnant and intermediate density lipoprotein (IDL). In this study, we examined whether liver-selective high-level expression of low-density lipoprotein receptor (LDLR) could affect the lipoprotein profile and atherogenesis in apoE-deficient (apoE-/-) mice. ApoE knockout mice expressing LDLR transgene in liver [apoE-/-;Tg(LDLR+/-)] were prepared after mating apoE-/- mice with the human LDLR transgenic mice. The apoE-/-;Tg(LDLR+/-) and littermate apoE-/- mice were fed a normal diet and sacrificed at 18 weeks of age. (1) The plasma levels of cholesterol and triglyceride in apoE-/-;Tg(LDLR+/-) mice were 51 and 33% lower than those of apoE-/- mice, respectively. (2) In the plasma of apoE-/-;Tg(LDLR+/-) mice, the levels of apoB-containing lipoprotein were reduced and apoB100-containg particles were totally eliminated. (3) By histochemical analysis, apoE-/-;Tg(LDLR+/-) mice showed drastic suppression of early atherogenesis; the lesion area of these mice was 1/70 of that in the littermate apoE-/- mice. These results indicate that, even in apoE-defective subjects, induction of hepatic LDLR expression could protect from early atherogenesis.
Atherosclerosis 2000 Dec
PMID:Overexpression of low density lipoprotein receptor eliminates apolipoprotein B100-containing lipoproteins from circulation and markedly prevents early atherogenesis in apolipoprotein E-deficient mice. 1116 18

The expression of macrophage scavenger receptors is regulated by intracellular cholesterol levels, as well as by cytokines affecting macrophage effector functions. CD36, a member of the type B scavenger receptor family, will bind a variety of nonlipoprotein and lipoprotein ligands including high-density lipoprotein (HDL). Transforming growth factor-beta (TGF-beta) has been demonstrated to modulate macrophage effector functions and is present within atherosclerotic lesions. In the present study, the effect of TGF-beta on HDL binding by both macrophages and macrophage-derived foam cells was evaluated. TGF-beta, in a dose-dependent manner, reduced the binding of flurochrome-labeled HDL to both macrophages and foam cells. These effects were observed in macrophages derived from nonatherosclerotic (BALB/c) as well as from macrophages obtained from both apolipoprotein E and low-density lipoprotein receptor knockout mice. The decrease in HDL binding was consistent with a significant reduction in CD36 message levels. The effect of TGF-beta on type B scavenger receptor expression was not limited to CD36 as SR-BI message was also downregulated, although the effect was more modest. A similar reduction in HDL binding and CD36 message was also observed with the immunosuppressive glucocorticoid dexamethasone. These results suggest that within the microenvironment of an atherosclerotic lesion, TGF-beta and other agents that inhibit macrophage inflammatory responses may impact lesion progression through mechanisms that include the modulation of HDL-foam cell interactions.
Atherosclerosis 2001 Mar
PMID:TGF-beta reduced binding of high-density lipoproteins in murine macrophages and macrophage-derived foam cells. 1122 29

To examine the role of the platelet adhesion molecule von Willebrand factor (vWf) in atherogenesis, vWf-deficient mice (vWf-/-) were bred with mice lacking the low-density lipoprotein receptor (LDLR-/-) on a C57BL/6J background. LDLR-/-vWf+/+ and LDLR-/-vWf-/- mice were placed on a diet rich in saturated fat and cholesterol for different lengths of time. The atherogenic diet stimulated leukocyte rolling in the mesenteric venules in both genotypes, indicating an increase in P-selectin-mediated adhesion to the endothelium. After 8 weeks on the atherogenic diet, the fatty streaks formed in the aortic sinus of LDLR-/-vWf-/- mice of either sex were 40% smaller and contained fewer monocytes than those in LDLR-/-vWf+/+ mice. After 22 weeks on the atherogenic diet (early fibrous plaque stage), the difference in lesion size in the aortic sinus persisted. Interestingly, the lesion distribution in the aortas of LDLR-/-vWf-/- animals was different from that of LDLR-/- vWf+/+ animals. In vWf-positive mice, half of all lesions were located at the branch points of the renal and mesenteric arteries, whereas lesions in this area were not as prominent in the vWf-negative mice. These results indicate that the absence of vWf primarily affects the regions of the aorta with disturbed flow that are prone to atherosclerosis. Thus, vWf may recruit platelets/leukocytes to the lesion in a flow-dependent manner or may be part of the mechano-transduction pathway regulating endothelial response to shear stress.
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PMID:Localized reduction of atherosclerosis in von Willebrand factor-deficient mice. 1152 Jul 91

The effect of probucol on atheroma formation was evaluated using mouse models for atherosclerosis with different diet protocols. Dietary administration of probucol (0.5 %, wt/wt) for 12 weeks reduced total plasma cholesterol levels in both apolipoprotein E (apoE)-deficient mice fed a western diet and in low-density lipoprotein receptor (LDLR)-deficient mice fed a Paigen diet by 60 % and 30 % to 60 %, respectively. Probucol treatment also significantly reduced high-density lipoprotein (HDL) levels in apoE-deficient mice, but not in LDLR-deficient mice. Atherosclerotic plaques in the aortic sinus of probucol-treated apoE-deficient mice were two-fold larger than those in untreated apoE-deficient mice, while the lesions in probucol-treated LDLR-deficient mice were similar to those in untreated LDLR-deficient mice. A strong negative correlation between HDL cholesterol levels and lesion sizes at the aortic sinus was observed in apoE-deficient mice, but not in LDLR-deficient mice. Thus, in contrast to LDLR-deficient mice, probucol had a strong proatherogenic effect in the aortic sinus of apoE-deficient mice associated with the reduction of HDL levels in spite of the reduction of total plasma cholesterol levels. The varying effects of probucol on atherogenesis depend upon the portion of aorta and which animal model is evaluated, implicating that complex cellular events are involved in the effect of probucol.
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PMID:Effects of probucol on atherosclerosis of apoE-deficient or LDL receptor-deficient mice. 1154 61

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