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 aims of this study were to determine whether mice induced to become obese also exhibited accelerated atherosclerosis, and to determine whether obesity itself or dyslipidemia associated with obesity enhanced atherosclerosis. Wild-type (C57BL/6) mice and mice deficient for the low density lipoprotein receptor (LDLR-/-) or apolipoprotein E (apoE-/-) were fed a low fat, rodent chow diet or a high fat, high sucrose (diabetogenic) diet to induce obesity. As compared with wild-type mice, diabetogenic diet-fed LDLR-/- mice became more obese and developed severe dyslipidemia. Consequently, atherosclerotic lesions were increased in the LDLR-/- mice 3.7-fold over chow fed values. ApoE-/- mice showed weight gain profiles similar to those observed for wild-type mice. However, no differences in plasma lipid levels, lipoprotein profiles or atherosclerotic lesion areas were observed between chow-fed and diabetogenic diet-fed apoE-/- mice. These data demonstrate that lipid storage and partitioning as mediated by the low density lipoproteins (LDL) receptor or apoE-/- have profound and opposing consequences for dyslipidemia and atherosclerosis susceptibility associated with obesity.
Atherosclerosis 2003 Nov
PMID:Mice deficient in apolipoprotein E but not LDL receptors are resistant to accelerated atherosclerosis associated with obesity. 1464 5

The aim of this review is to give an overview of the field of restenosis prevention with antioxidants, put in the perspective of their potential use for the prevention of atherosclerosis progression. Compelling evidence points to oxidative stress as an important trigger in the complex chain of events leading to atherosclerosis. There is also evidence that oxidative stress occurs early after angioplasty. Reactive oxygen species (ROS) can induce endothelial dysfunction and macrophage activation, resulting in the release of cytokines and growth factors that stimulate matrix remodeling and smooth muscle cell proliferation. The accumulation of new extracellular matrix and smooth muscle cells will result in the neointimal formation responsible for lumen narrowing after stent deployment and which contributes to that after balloon angioplasty. In addition, oxidation processes are involved in the cross-linking of collagen fibers, and this coupled with smooth muscle cell contraction and endothelial dysfunction may result in long-term vascular constriction or lack of adaptive vascular remodeling after balloon angioplasty. The powerful antioxidant probucol has been shown to prevent coronary restenosis after balloon angioplasty in the Multivitamins and Probucol (MVP) trial and other clinical studies. However, prolongation of the QT interval with probucol remains a long-term safety concern. AGI-1067, a metabolically stable analog of probucol, is a vascular protectant with strong antioxidant properties as potent to those of probucol. There has been no evidence of prolongation of the QT interval with AGI-1067 in initial clinical studies. The anti-restenosis properties of AGI-1067 are being assessed in the Canadian Antioxidant Restenosis Trial (CART)-1. Considering that oxidative stress and inflammation may persist for a prolonged period after stent placement, treatment with AGI-1067 for the entire period of risk after percutaneous coronary intervention (PCI) [instead of only 4 weeks in CART-1] may result in enhanced protection against luminal renarrowing. This hypothesis will be tested in the randomized, multicenter CART-2 trial. AGI-1067 has been effective at preventing atherosclerosis in all tested animal models, including the low density lipoprotein receptor-deficient and apo-E knockout mice. This has potentially important implications, as PCI and local approaches to prevent restenosis such as coated stents are not expected to prevent atherosclerosis progression, myocardial infarction and cardiovascular death. As the ultimate goal of therapy for patients with coronary artery disease must remain prevention of disease progression and atherosclerosis-related events, CART-2 will test the value of AGI-1067 for the reduction of both post-PCI restenosis and atherosclerosis progression.
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PMID:Prevention of restenosis with antioxidants: mechanisms and implications. 1472 62

The individual roles of hepatic versus intestinal ABCG5 and ABCG8 in sterol transport have not yet been investigated. To determine the specific contribution of liver ABCG5/G8 to sterol transport and atherosclerosis, we generated transgenic mice that overexpress human ABCG5 and ABCG8 in the liver but not intestine (liver G5/G8-Tg) in three different genetic backgrounds: C57Bl/6, apoE-KO, and low density lipoprotein receptor (LDLr)-KO. Hepatic overexpression of ABCG5/G8 enhanced hepatobiliary secretion of cholesterol and plant sterols by 1.5-2-fold, increased the amount of intestinal cholesterol available for absorption and fecal excretion by up to 27%, and decreased the accumulation of plant sterols in plasma by approximately 25%. However, it did not alter fractional intestinal cholesterol absorption, fecal neutral sterol excretion, hepatic cholesterol concentrations, or hepatic cholesterol synthesis. Consequently, overexpression of ABCG5/G8 in only the liver had no effect on the plasma lipid profile, including cholesterol, HDL-C, and non-HDL-C, or on the development of proximal aortic atherosclerosis in C57Bl/6, apoE-KO, or LDLr-KO mice. Thus, liver ABCG5/G8 facilitate the secretion of liver sterols into bile and serve as an alternative mechanism, independent of intestinal ABCG5/G8, to protect against the accumulation of dietary plant sterols in plasma. However, in the absence of changes in fractional intestinal cholesterol absorption, increased secretion of sterols into bile induced by hepatic overexpression of ABCG5/G8 was not sufficient to alter hepatic cholesterol balance, enhance cholesterol removal from the body or to alter atherogenic risk in liver G5/G8-Tg mice. These findings demonstrate that overexpression of ABCG5/G8 in the liver profoundly alters hepatic but not intestinal sterol transport, identifying distinct roles for liver and intestinal ABCG5/G8 in modulating sterol metabolism.
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PMID:Hepatic ABCG5 and ABCG8 overexpression increases hepatobiliary sterol transport but does not alter aortic atherosclerosis in transgenic mice. 1504 50

BACKGROUND: In humans, overproduction of apolipoprotein B (apoB) is positively associated with premature coronary artery diseases. To reduce the levels of apoB mRNA, we have designed an apoB mRNA-specific hammerhead ribozyme targeted at nucleotide sequences GUA6679 (RB15) mediated by adenovirus, which efficiently cleaves and decreases apoB mRNA by 80% in mouse liver and attenuates the hyperlipidemic condition. In the current study, we used an adeno-associated virus vector, serotype 2 (AAV2) and a self-complementary AAV2 vector (scAAV2) to demonstrate the effect of long-term tissue-specific gene expression of RB15 on the regulation apoB mRNA in vivo. METHODS: We constructed a hammerhead ribozyme RB15 driven by a liver-specific transthyretin (TTR) promoter using an AAV2 vector (rAAV2-TTR-RB15). HepG2 cells and hyperlipidemic mice deficient in both the low density lipoprotein receptor and the apoB mRNA editing enzyme genes (LDLR-/-Apobec1-/-; LDb) were transduced with rAAV2-TTR-RB15 and a control vector rAAV-TTR-RB15-mutant (inactive ribozyme). The effects of ribozyme RB15 on apoB metabolism and atherosclerosis development were determined in LDb mice at 5-month after transduction. A self-complementary AAV2 vector expressing ribozyme RB15 (scAAV2-TTR-RB15) was also engineered and used to transduce HepG2 cells. Studies were designed to compare the gene expression efficiency between rAAV2-TTR-RB15 and scAAV2-TTR-RB15. RESULTS: The effect of ribozyme RB15 RNA on reducing apoB mRNA levels in HepG2 cells was observed only on day-7 after rAAV2-TTR-RB15 transduction. And, at 5-month after rAAV2-TTR-RB15 treatment, the apoB mRNA levels in LDb mice were significantly decreased by 43%, compared to LDb mice treated with control vector rAAV2-TTR-RB15-mutant. Moreover, both the rAAV2-TTR-RB15 viral DNA and ribozyme RB15 RNA were still detectable in mice livers at 5-month after treatment. However, this rAAV2-TTR-RB15 vector mediated a prolonged but low level of ribozyme RB15 gene expression in the mice livers, which did not produce the therapeutic effects on alteration the lipid levels or the inhibition of atherosclerosis development. In contrast, the ribozyme RB15 RNA mediated by scAAV2-TTR-RB15 vector was expressed immediately at day-1 after transduction in HepG2 cells. The apoB mRNA levels were decreased 47% (p = 0.001), compared to the control vector scAAV2-TTR-RB15-mutant. CONCLUSION: This study provided evidence that the rAAV2 single-strand vector mediated a prolonged but not efficient transduction in mouse liver. However, the scAAV2 double-strand vector mediated a rapid and efficient gene expression in liver cells. This strategy using scAAV2 vectors represents a better approach to express small molecules such as ribozyme.
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PMID:The recombinant adeno-associated virus vector (rAAV2)-mediated apolipoprotein B mRNA-specific hammerhead ribozyme: a self-complementary AAV2 vector improves the gene expression. 1519 53

Primary hyperlipidemia is caused by various molecular defects in lipid metabolism. The Research Committee on Primary Hyperlipidemia organized by the Ministry of Health and Welfare of Japan (present: the Ministry of Health, Labour and Welfare) has investigated reported mutations in Japanese patients with primary hyperlipidemia and related disorders (including hypolipidemia), and has created a database based on the questionnaire sent to the members of council board of the Japan Atherosclerosis Society. Mutations in the following genes were investigated: low density lipoprotein receptor, lecithin: cholesteryl acyltransferase, lipoprotein lipase (LPL), hepatic lipase, apolipoproteins A-I, A-II, A-IV, B, C-II, C-III and E, microsomal triglyceride transfer protein, and cholesterol ester transfer protein (CETP). Until 1998, 922 patients with primary hyperlipidemia and related disorders has been registered with the Research Committee, and 190 mutations in 15 genes had been reported, showing a marked variation in Japanese patients with primary hyperlipidemia and related disorders. So-called "common mutations" have been described in Japanese patients with familial hypercholesterolemia, LPL deficiency and CETP deficiency. The genetic defect of familial combined hyperlipidemia (FCHL) is still unknown although FCHL is speculated to be the most prevalent genetic hyperlipidemia, and further investigations should be performed to elucidate the molecular mechanisms of FCHL
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PMID:Mutations in Japanese subjects with primary hyperlipidemia--results from the Research Committee of the Ministry of Health and Welfare of Japan since 1996--. 1525 64

Differences in affinity of human apolipoprotein E (apoE) isoforms for the low density lipoprotein receptor (LDLR) are thought to result in the differences in lipid metabolism observed in humans with different APOE genotypes. Mice expressing three common human apoE isoforms, E2, E3, and E4, in place of endogenous mouse apoE were used to investigate the relative roles of apoE isoforms in LDLR- and non-LDLR-mediated very low density lipoprotein (VLDL) clearance. While both VLDL particles isolated from mice expressing apoE3 and apoE4 bound to mouse LDLR with affinity and Bmax similar to VLDL containing mouse apoE, VLDL with apoE2 bound with only half the Bmax. In the absence of the LDLR, all lines of mice expressing human apoE showed dramatic increases in VLDL cholesterol and triglycerides (TG) compared to LDLR knockout mice expressing mouse apoE. The mechanism of the hyperlipidemia in mice expressing human apoE isoforms is due to impairment of non-LDL-receptor-mediated VLDL clearance. This results in the severe atherosclerosis observed in mice expressing human apoE but lacking the LDLR, even when fed normal chow diet. Our data show that defects in LDLR independent pathway(s) are a potential factor that trigger hyperlipoproteinemia when the LDLR pathway is perturbed, as in E2/2 mice.
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PMID:Defective VLDL metabolism and severe atherosclerosis in mice expressing human apolipoprotein E isoforms but lacking the LDL receptor. 1545 Feb 5

The lectin-like oxidized low density lipoprotein receptor-1 (Lox-1) mediates the recognition and internalization of oxidatively modified low density lipoprotein by vascular endothelial cells. This interaction results in a number of pro-atherogenic cellular responses that probably play a significant role in the pathology of atherosclerosis. The 1.4 angstrom crystal structure of the extracellular C-type lectin-like domain of human Lox-1 reveals a heart-shaped homodimer with a ridge of six basic amino acids extending diagonally across the apolar top of Lox-1, a central hydrophobic tunnel that extends through the entire molecule, and an electrostatically neutral patch of 12 charged residues that resides next to the tunnel at each opening. Based on the arrangement of critical binding residues on the Lox-1 structure, we propose a binding mode for the recognition of modified low density lipoprotein and other Lox-1 ligands.
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PMID:The 1.4 angstrom crystal structure of the human oxidized low density lipoprotein receptor lox-1. 1569 3

Individuals with a heterozygous mutation at the ataxia-telangiectasia mutated gene (ATM) have been reported to be predisposed to ischemic heart disease. This report examined for the first time the effect of a heterozygous ATM mutation (ATM(+)(/-)) on plasma lipid levels and atherosclerosis intensity using ATM(+/-), ATM(+)(/+) (wild type), ATM(+)(/+)/LDLR(-)(/-) (low density lipoprotein receptor knockout), ATM(+)(/-)/LDLR(-)(/-), ATM(+)(/+)/ApoE(-)(/-) (apolipoprotein E knockout), and ATM(+)(/-)/ApoE(-)(/-) mice. Our data demonstrated that the plasma cholesterol and triglyceride levels in ATM(+)(/-) and ATM(+)(/-)/LDLR(-)(/-) mice were approximately the same as those in ATM(+)(/+) and ATM(+)(/+)/LDLR(-)(/-) control mice, respectively. In contrast, the plasma cholesterol level was significantly higher in ATM(+)(/-)/ApoE(-)(/-) mice than in ATM(+)(/+)/ApoE(-)(/-) control mice. In addition, the ATM(+)(/-)/ApoE(-)(/-) mice showed higher plasma apoB-48 levels, slower clearance for plasma apoB-48-carrying lipoproteins, and more advanced atherosclerotic lesions in the aorta compared with the ATM(+)(/+)/ApoE(-)(/-) mice. These novel results suggest that the product of ATM is involved in an apoE-independent pathway for catabolism of apoB-48-carrying remnants; therefore, superimposition of a heterozygous ATM mutation onto an ApoE deficiency background reduces the clearance of apoB-48-carrying lipoproteins from the blood circulation and promotes the formation of atherosclerosis.
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PMID:Heterozygous mutation of ataxia-telangiectasia mutated gene aggravates hypercholesterolemia in apoE-deficient mice. 1586 39

Familial hypercholesterolaemia is a clinical entity comprising high concentrations of low density lipoproteins, tendinous deposition of cholesterol in a large proportion of affected subjects, and a propensity for the development of atherosclerosis and its complications in the coronary arteries. The aim of this review is to integrate publications with clinical experience into a concise profile of the disorder and its management. In less than a century this disease has been recognised, its lipoprotein derangement identified and numerous causal mutations have been detected. Although the phenotype is most commonly due to the occurrence of mutations in the low density lipoprotein receptor, defects in the apolipoprotein B100 may result in a similar phenotype. The same phenotype has also been linked to a gene and its product, PCSK9 and NARC1, that may be involved in the regulation of cholesterol in the cell. In the past few decades statins, by inhibiting cholesterol synthesis at the rate-limiting enzyme (hydroxymethylglutaryl coenzyme A reductase) have been developed and proven safe and effective in reducing the low density lipoprotein cholesterol, promoting regression and reducing mortality and morbidity. Additionally, advances in imaging techniques are allowing non-invasive insights into the impact of the disease on atherosclerosis. For these reasons there should be a high index of suspicion for this treatable condition in which genetic therapy and further modulation of atherosclerosis can be expected in the future.
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PMID:The diagnosis and management of familial hypercholesterolaemia. 1608 Jun 33

Despite a clear association between obesity, insulin resistance and atherosclerosis in humans, to date, no animal models have been described in which insulin resistance is associated with atherosclerotic lesion burden. Using two mouse models of obesity-induced hyperlipidemia:leptin deficient (ob/ob) mice on an apolipoprotein E deficient (apoE-/-) or low density lipoprotein receptor deficient (LDLR-/-) background, we sought to determine metabolic parameters most closely associated with atherosclerotic lesion burden. Total plasma cholesterol (TC) levels in ob/ob;apoE-/- mice and ob/ob;LDLR-/- mice were indistinguishable (682+/-48 versus 663+/-16, respectively). Analysis of lipoprotein profiles showed that cholesterol was carried primarily on VLDL in the ob/ob;apoE-/- mice and on LDL in the ob/ob;LDLR-/- mice. Plasma triglycerides (TG) were 55% lower (P<0.001), non-esterified fatty acids (NEFA) were 1.5-fold higher (P<0.01), and insulin levels were 1.7-fold higher (NS) in ob/ob;apoE-/- mice compared to ob/ob;LDLR-/- mice. Other parameters such as body weight, fat pad weight, and glucose levels were not different between the groups. Aortic sinus lesion area of ob/ob;apoE-/- mice was increased 3.2-fold above ob/ob;LDLR-/- mice (102,455+/-8565 microm2/section versus 31,750+/-4478 microm2/section, P<0.001). Lesions in ob/ob;apoE-/- mice were also more complex as evidenced by a 7.7-fold increase in collagen content (P<0.001). Atherosclerotic lesion area was positively correlated with body weight (P<0.005), NEFA (P=0.007), and insulin (P=0.002) levels in the ob/ob;LDLR-/- mice and with insulin (P=0.014) in the ob/ob;apoE-/- mice. In contrast, lesion burden was neither associated with TC and TG, nor with individual lipoprotein pools, in either animal model. These data provide a direct demonstration of the pathophysiologic relevance of hyperinsulinemia, NEFA, and increased body weight to atherosclerotic lesion formation.
Atherosclerosis 2006 May
PMID:Plasma insulin levels predict atherosclerotic lesion burden in obese hyperlipidemic mice. 1610 72

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