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

Vascular smooth muscle cells (SMCs) are exposed to altered mechanical stress that may contribute to SMC migration in the development of atherosclerosis. Signal transduction pathways in SMCs activated by mechanical stress that instigate cell migration are undefined. Herein, we provide evidence that mechanical stress enhances SMC migration, which is mediated, at least in part, by protein kinase C (PKC)delta. When rat SMCs cultivated on a flexible membrane were subjected to cyclic strain stress (60 cycles/min, 5, 15, or 20% elongation), PKCdelta was translocated to the Triton-insoluble fraction, whereas PKCalpha was translocated to the membrane, which was confirmed by PKC kinase assays. Immunofluorescence and actin staining revealed a cytoskeleton translocation of PKCdelta in SMCs stimulated by cyclic strain. PKCdelta-deficient SMCs cultivated from PKCdelta-/- mice showed an abnormal cytoskeleton structure, which was related to a diminished phosphorylation of paxillin, focal adhesion kinase, and vinculin in response to mechanical stress. Mechanical stress enhanced SMC migration, which was diminished in PKCdelta-/- SMCs. Taken together, our data demonstrated that mechanical stress activates PKCdelta translocation to the cytoskeleton, which is related to decreased SMC migration and indicates that PKCdelta is a key signal transducer between mechanical stress and cell migration.
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PMID:Mechanical stress-activated PKCdelta regulates smooth muscle cell migration. 1295 54

A study was made of the relationship of blood lipids to the development of experimental atherosclerosis. Rabbits fed a diet containing cholesterol were found to develop hyperlipemia characterized by a great increase in blood cholesterol and a much lesser increase in blood phospholipids; after several weeks they manifested conspicuous atherosclerosis of the aorta, as has often been observed by others. Comparable rabbits fed the same diets containing added cholesterol were given in addition repeated intravenous injections of the surface-active agents Tween 80 and Triton A20; these animals developed hyperlipemia which was characterized by a great increase in blood cholesterol and an equivalent or even greater increase in phospholipids, and they had much less atherosclerosis than did the control rabbits fed cholesterol alone. In further experiments it was observed that repeated intravenous injections of Tween 80 did not result in resorption of previously induced atherosclerosis in rabbits. The findings are discussed in relation to the pathogenesis of natural and experimental atherosclerosis.
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PMID:The influence of intravenously administered surface-active agents on the development of experimental atherosclerosis in rabbits. 1482 10

LDL receptor-deficient (LDLR(-/-)) mice fed a Western diet exhibit severe hyperlipidemia and develop significant atherosclerosis. Apolipoprotein E (apoE) is a multifunctional protein synthesized by hepatocytes and macrophages. We sought to determine effect of macrophage apoE deficiency on severe hyperlipidemia and atherosclerosis. Female LDLR(-/-) mice were lethally irradiated and reconstituted with bone marrow from either apoE(-/-) or apoE(+/+) mice. Four weeks after transplantation, recipient mice were fed a Western diet for 8 weeks. Reconstitution of LDLR(-/-) mice with apoE(-/-) bone marrow resulted in a slight reduction in plasma apoE levels and a dramatic reduction in accumulation of apoE and apoB in the aortic wall. Plasma lipid levels were unaffected when mice had mild hyperlipidemia on a chow diet, whereas IDL/LDL cholesterol levels were significantly reduced when mice developed severe hyperlipidemia on the Western diet. The hepatic VLDL production rate of mice on the Western diet was decreased by 46% as determined by injection of Triton WR1339 to block VLDL clearance. Atherosclerotic lesions in the proximal aorta were significantly reduced, partially due to reduction in plasma total cholesterol levels (r=0.56; P<0.0001). Thus, macrophage apoE-deficiency alleviates severe hyperlipidemia by slowing hepatic VLDL production and consequently reduces atherosclerosis in LDLR(-/-) mice.
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PMID:Effect of macrophage-derived apolipoprotein E on hyperlipidemia and atherosclerosis of LDLR-deficient mice. 1504 72

The 75th European Atherosclerosis Society congress, held in Prague, Czech Republic, at the end of April 2005, was a large, well-attended meeting of international scientists with specialist interest in the field of cardiovascular diseases. Few new drugs emerged at the meeting as treatment options for cardiovascular diseases, however, many interesting basic and clinical data were presented that will eventually lead to better and improved cardiovascular therapies. This report is focused on recent advances in statin therapy (the TNT study and the role of pharmacogenetics in predicting individual response to statin therapy); clinical evidence of the combination therapy of ezetimibe + simvastatin; phase III clinical data on the selective cannabinoid type I receptor blocker rimonabant (sanofi-aventis); the role of peroxisome proliferator-activated receptor a agonists in the treatment of the metabolic syndrome; and the rationale for, and the recent advances in high-density lipoprotein-targeted therapy.
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PMID:European Atherosclerosis Society--75th congress. 1597 62

Animals of various species are widely used as models with which to study atherosclerosis and the lipoprotein metabolism. The objective of this study was to investigate the lipoprotein profiles in Wistar rats and New Zealand white rabbits with experimentally induced hyperlipidemia by means of ultracentrifugation. The Schlieren curves were utilized to compare suckling and adult rat sera to determine whether aging causes alterations in lipoprotein profiles. A striking feature of the data is the high concentration of low-density lipoproteins (LDL), (>5.2 mmol/l cholesterol) in the 2-week old rat serum pool which was greatly decreased in the 3-weeks rat serum pool (<1.3 mmol/l cholesterol). Additional experiments were performed to permit a direct comparison of the amounts of lipoprotein present in rat sera in experimental hyperlipidemia post-Triton WR 1339 administration. Rapid changes in concentrations in very low-density lipoproteins (VLDL), LDL and high-density lipoproteins (HDL) were observed after Triton injection. The administration of Triton WR 1339 to fasted rats resulted in an elevation of serum cholesterol levels. Triton physically alters VLDL, rendering them refractive to the action of lipolytic enzymes in the blood and tissues, preventing or delaying their removal from the blood. Whereas the VLDL concentration was increased markedly, those of LDL and HDL were decreased at 20 h after Triton treatment. Rabbits were fed a diet containing 2% cholesterol for 60 days to develop hyperlipidemia and atheromatous aortic plaques. A combination of preparative and analytical ultracentrifugation was used to investigate of LDL aliquots, to prepare radioactive-labeled lipoproteins and to study induced hyperlipidemia in rabbits. Analytical ultracentrifugation was applied to investigate the LDL flotation peaks before and after cholesterol feeding of rabbits. Modified forms of LDL were detected in the plasma of rabbits with experimentally induced atherosclerosis. ApoB-containing particles, migrating as LDL, intermediate density lipoproteins and VLDL were the most abundant lipoproteins. Gamma camera in vivo scintigraphy on rabbits with radiolabeled lipoproteins revealed visible signals corresponding to atherosclerotic plaques of the aorta and carotid arteries.
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PMID:Evaluation of rat and rabbit sera lipoproteins in experimentally induced hyperlipidemia by analytical ultracentrifugation. 1630 70

Hyperlipidaemia, atherosclerosis and related diseases are becoming a major health problem in developing countries. Ocimum basilicum is one of the medicinal plants widely used in Morocco to reduce plasma cholesterol and to reduce the risk of atherosclerosis-related diseases. However, mechanisms underlying the reported hypolipidaemic effect of this plant have not been investigated. This study evaluates the lipid lowering effect of aqueous Ocimum basilicum extract in Triton WR-1339-induced hyperlipidaemic rats. Hyperlipidaemia was developed in animals by intraperitoneal injection of Triton (200 mg/kg). After injection of Triton the animals were divided into three treatment groups: hyperlipidaemic, hyperlipidaemic plus herb extract and hyperlipidaemic plus fenofibrate treated rats. At 7 h after the Triton injection, levels of plasma cholesterol, triglycerides and LDL-cholesterol in rats treated also with the Ocimum basilicum extract (0.5 g/100 g body weight) were, respectively, 50%, 83% and 79% lower than Triton-treated rats and HDL-cholesterol was 129% higher than in rats given Triton alone. At 24 h following Ocimum basilicum administration, total cholesterol, triglycerides and LDL-cholesterol levels decreased by 56%, 63% and 68%, respectively, in comparison with the Triton treated group and HDL-cholesterol was not increased significantly. The hypolipidaemic effect exerted by Ocimum basilicum extract was markedly stronger than the effect induced by fenofibrate treatments. Further it was demonstrated that Ocimum basilicum aqueous extract displayed a very high antioxidant power. These results indicate that Ocimum basilicum extract may contain hypolipidaemic and antioxidant substances and its use as a therapeutic tool in hyperlipidaemic subjects may be of benefit and encourage further investigation in this field.
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PMID:Hypolipidaemic activity of aqueous Ocimum basilicum extract in acute hyperlipidaemia induced by triton WR-1339 in rats and its antioxidant property. 1700 76

The Hyplip2 congenic mouse strain contains part of chromosome 15 from MRL/MpJ on the BALB/cJ background. Hyplip2 mice show increased plasma levels of cholesterol and predominantly triglycerides (TGs) and are susceptible to diet-induced atherosclerosis. This study aimed at elucidation of the mechanism(s) explaining the hypertriglyceridemia. Hypertriglyceridemia can result from increased intestinal or hepatic TG production and/or by decreased LPL-mediated TG clearance. The intestinal TG absorption and chylomicron formation were studied after intravenous injection of Triton WR1339 and an intragastric load of olive oil containing glycerol tri[(3)H]oleate. No difference was found in intestinal TG absorption. Moreover, the hepatic VLDL-TG production rate and VLDL particle production, after injection of Triton WR1339, were also not affected. To investigate the LPL-mediated TG clearance, mice were injected intravenously with glycerol tri[(3)H]oleate-labeled VLDL-like emulsion particles. In Hyplip2 mice, the particles were cleared at a decreased rate (half-life of 25 +/- 6 vs. 11 +/- 2 min; P < 0.05) concomitant with a decreased uptake of emulsion TG-derived (3)H-labeled fatty acids by the liver and white adipose tissue. The increased plasma TG levels in Hyplip2 mice do not result from an enhanced intestinal absorption or increased hepatic VLDL production but are caused by decreased LPL-mediated TG clearance.
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PMID:The Hyplip2 locus causes hypertriglyceridemia by decreased clearance of triglycerides. 1760 25

Evidence of the effectiveness of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) within continuum of atherothrombotic conditions and particularly in the treatment and prevention of coronary heart disease (CHD) is well established. Large-scale, randomized, prospective trials involving patients with CHD have shown that statins reduce the clinical consequences of atherosclerosis, including cardiovascular deaths, nonfatal myocardial infarction and stroke, hospitalization for acute coronary syndrome and heart failure, as well as the need for coronary revascularization. Direct testing of varying degrees of low-density lipoprotein (LDL)- cholesterol lowering has now been carried out in 4 large outcomes trials: PROVE IT-TIMI 22, A to Z, TNT and IDEAL. However, the question whether more aggressive LDL-cholesterol lowering by high-dose statins monotherapy is an appropriate strategy is still open: higher doses of statins are more effective mainly for the prevention of the nonfatal cardiovascular events but such doses are associated with an increase in hepatotoxicity, myopathy and concerns regarding noncardiovascular death. Moreover, despite the increasing use of statins, a significant number of coronary events still occur and many such events take place in patients presenting with type 2 diabetes and metabolic syndrome. More and more attention is now being paid to combined atherogenic dyslipidemia which typically presented in patients with type 2 diabetes and metabolic syndrome. This mixed dyslipidemia (or 'lipid quartet') - hypertriglyceridemia, low high-density lipoprotein (HDL)-cholesterol levels, a preponderance of small, dense LDL particles and an accumulation of cholesterol-rich remnant particles - emerged as the greatest 'competitor' of LDL-cholesterol among lipid risk factors for cardiovascular disease. Most recent extensions of the fibrates trials (BIP, HHS, VAHIT and FIELD) give further support to the hypothesis that patients with insulin-resistant syndromes such as diabetes and/or metabolic syndrome might be the ones to derive the most benefit from therapy with fibrates. However, different fibrates may have a somewhat different spectrum of effects. Other lipid-modifying strategies included using of niacin, ezetimibe, bile acid sequestrants, CETP inhibitors and omega-3 fatty acids. Particularly, ezetimibe/statins combinations provide superior lipid-modifying benefits compared Tenenbaum/Fisman/Motro/Adler 128 with any statins monotherapy in patients with atherogenic dyslipidemia. Atherogenic dyslipidemia is associated with increased levels of chylomicrons and their remnants containing 3 main components: apolipoprotein B-48, triglycerides and cholesterol ester of intestinal origin. Reduction in accessibility for one of them (specifically cholesteryl ester lessening due to ezetimibe administration) could lead to a decrease of the entire production of chylomicrons and result in a decrease of the hepatic body triglycerides pool as confirmed in number of clinical studies. However, the ENHANCE study showed no difference in the progression of carotid atherosclerosis between ezetimibe/simvastatin vs. simvastatin alone over a 2-year period. Conclusions regarding ezetimibe/statins combinations should not be made until the three large clinical outcome trials will be completed within the next 2-3 years. In addition, bezafibrate as a pan-PPAR activator has clearly demonstrated beneficial pleiotropic effects related to glucose metabolism, insulin sensitivity and pancreatic beta cell protection. Because fibrates, niacin, ezetimibe, omega-3 fatty acids and statins each regulate serum lipids by different mechanisms, combination therapy - selected on the basis of their safety and effectiveness, could be more helpful in achieving a comprehensive lipid control as compared with statins monotherapy.
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PMID:Optimal management of combined dyslipidemia: what have we behind statins monotherapy? 1823 Sep 60

Two fractions (S1 and S2) of an oregano (Origanum vulgare) extract obtained by supercritical fluid extraction have been used to test anti-inflammatory effects on activated human THP-1 cells. The main compounds present in the supercritical extract fractions of oregano were trans-sabinene hydrate, thymol and carvacrol. Fractions toxicity was assessed using the mitochondrial-respiration-dependent 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) reduction method for several concentrations during 24 and 48 h of incubation. Concentrations higher than 30 microg/mL of both supercritical S1 and S2 oregano fractions caused a reduction in cell viability in a dose-dependent manner. Oxidized-LDLs (oxLDLs) activated THP-1 macrophages were used as cellular model of atherogenesis and the release/secretion of cytokines (TNT-alpha, IL-1beta, IL-6 and IL-10) and their respective mRNA expressions were quantified both in presence or absence of supercritical oregano extracts. The results showed a decrease in pro-inflammatory TNF-alpha, IL-1beta and IL-6 cytokines synthesis, as well as an increase in the production of anti-inflammatory cytokine IL-10. These results may suggest an anti-inflammatory effect of oregano extracts and their compounds in a cellular model of atherosclerosis.
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PMID:Supercritical fluid extraction of oregano (Origanum vulgare) essentials oils: anti-inflammatory properties based on cytokine response on THP-1 macrophages. 2033 13

Lowering LDL cholesterol (LDL-C) with statins decreases cardiovascular risk; therefore LDL-C is the primary target in lipid therapy. The amount of risk reduction is the greater, the lower the LDL-C values achieved by statin therapy are. Current guidelines therefore require an LDL-C as low as < 70 mg/dl in patients who are at a very high risk of cardiovascular events. This stringent treatment goal depending on the baseline LDL-C values typically can only be obtained with higher doses of potent statins. Randomised trials demonstrate the efficacy of high-dose therapy with atorvastatin 80 mg/day with regard to the prevention of cardiovascular events in patients after acute coronary syndromes (PROVE-IT TIMI 22 trial), in patients with stable coronary artery disease (TNT trial), and in patients after stroke or TIA (SPARCL trial). Moreover, potent statin treatment reduces the progression of coronary atherosclerosis (REVERSAL and ASTEROID trials). Furthermore, large meta-analyses of the efficacy of high-dose statin therapy confirm its safety; in particular, muscle-related adverse events are not more frequent than with standard statin doses. It is recommended that evidence-based statin doses be used in clinical practice; the dosages used in clinical trials should be given rather than titrating patients to LDL-C targets by increasing statin doses in a stepwise manner. Whether the strong LDL-C lowering combination of simvastatin plus ezetimibe will reduce cardiovascular events over and above simvastatin monotherapy is currently being tested in the ongoing IMPROVE-IT trial. Importantly, despite the large body of evidence in favour of high-dose statin therapy for patients at high cardiovascular risk, high-dose statin therapy is still underused and LDL-C goals are still not met in the majority of these patients.
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PMID:[High-dose statin therapy for high-risk patients]. 2094 69


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