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

We investigated the differences between the hypocholesterolemic effects induced by dietary linoleic acid and those induced by oleic acid in hamsters. Addition of 5% linoleic acid or oleic acid to a 0.1% cholesterol-supplemented diet diminished the increases in plasma total and low density lipoprotein (LDL) cholesterol induced by cholesterol alone. Linoleic acid decreased high density lipoprotein (HDL) cholesterol in comparison with cholesterol alone, whereas oleic acid did not. As compared with a standard diet or a cholesterol-supplemented diet, linoleic acid and oleic acid each prevented hepatic LDL receptor suppression, although linoleic acid was more effective. Oleic acid prevented the increase in plasma cholesteryl ester transfer protein (CETP) activity induced by dietary cholesterol, whereas linoleic acid did not. Neither linoleic acid nor oleic acid altered hepatic 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase activity. Only oleic acid increased hepatic cholesterol 7 alpha-hydroxylase activity. These results suggest that dietary linoleic and oleic acids diminish the cholesterol-induced increases in plasma total and LDL-cholesterol by preventing hepatic LDL receptor suppression, and in the case of oleic acid by also preventing the increase in the plasma CETP activity. These effects on cholesterol 7 alpha-hydroxylase activity may influence bile lipid metabolism.
Atherosclerosis 1995 Apr 24
PMID:Comparison of hypocholesterolemic effects induced by dietary linoleic acid and oleic acid in hamsters. 760 90

Agents that inhibit hepatic cholesterol biosynthesis reduce circulating cholesterol levels in experimental animals and humans, and may be of pharmacological importance in the prevention of atherosclerosis. Azalanstat (RS-21607), a synthetic imidazole, has been shown to inhibit cholesterol synthesis in HepG2 cells, human fibroblasts, hamster hepatocytes and hamster liver, by inhibiting the cytochrome P450 enzyme lanosterol 14 alpha-demethylase. When administered orally to hamsters fed regular chow, RS-21607 (50 mg/kg/day) lowered serum cholesterol in a dose-dependent manner (ED50 = 62 mg/kg) in a period of 1 week. It preferentially lowered low density lipoprotein (LDL) cholesterol and apo B relative to high density lipoprotein (HDL) cholesterol and apo A-1. It also lowered plasma cholesterol levels in hamsters fed a high saturated fat and cholesterol diet. RS-21607 inhibited hepatic microsomal hydroxymethylglutaryl-CoA (HMG-CoA) reductase activity in hamsters in a dose-dependent manner (ED50 = 31 mg/kg), and this was highly correlated with serum cholesterol lowering (r = 0.97). Cholesterol lowering by azalanstat and cholestyramine was additive, and the increase in HMG-CoA reductase brought about by cholestyramine was attenuated significantly by azalanstat. In vitro studies with HepG2 cells indicated that this modulation of reductase activity was indirect, occurring at a post-transcriptional step, and it is proposed that a regulatory oxysterol derived from dihydrolanosterol (or lanosterol) may be responsible for this regulation. Azalanstat does not appear to lower circulating cholesterol in the hamster by up-regulation of the hepatic LDL receptor, suggesting that other mechanisms are involved. Orally administered azalanstat (50-75 mg/kg) stimulated hepatic microsomal cholesterol 7 alpha-hydroxylase activity by 50-400% in hamsters, and it is postulated that this may result from modified cholesterol absorption and bile acid synthesis.
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PMID:Azalanstat (RS-21607), a lanosterol 14 alpha-demethylase inhibitor with cholesterol-lowering activity. 764 60

Several clinical trials have provided compelling evidence in support of the benefits of lipid-lowering therapy for primary and secondary prevention of atherosclerosis. The results of primary prevention trials have demonstrated that coronary morbidity can be reduced and survival improved with effective lipid-lowering regimens. There has been concern, however, regarding harmful effects (e.g., increased rate of suicide and increased risk of gastrointestinal cancer) of cholesterol-lowering therapies in primary prevention trials. These concerns are not well supported by strong evidence, and there has been lack of a dose-response relationship. It is generally believed that for 1% reduction in serum cholesterol, there is a 2% reduction in the risk of coronary events. The results of numerous secondary prevention trials have clearly demonstrated the benefit of lipid-lowering therapies in reducing the risk of future cardiac events and cardiac mortality in patients with preexistent coronary artery disease. Several studies have shown that treatment regimens effective in reducing LDL cholesterol levels lead to regression of atherosclerotic plaques as well as retard the progression of the disease process. Interestingly, some of these studies have also shown that when measured angiographically, the luminal diameter at the site of stenotic lesions might improve only by an average of 2% to 3%; however, this small degree of improvement is associated with a remarkable reduction by 35% to 25% in the risk of future coronary events. These findings further corroborate the hypothesis about the importance of a lipid-rich cap of the vulnerable plaques and suggest that the reduction in lipid levels is associated with the efflux of lipids from the plaque, thus converting it from a vulnerable to a stable state. The most recent data from the 4S trial have unequivocally demonstrated the benefits of treatment with HMG coenzyme-A reductase inhibitors in reducing the risk of future coronary events and improving the overall survival in patients with established CHD. Although there is still ongoing controversy regarding the precise course of action for primary prevention of CHD, the results of a large number of studies provide overwhelming evidence in support of aggressive lipid-lowering therapy for secondary prevention of CHD. Based on the findings of these studies, it seems prudent that clinicians become actively involved in the evaluation and management of lipid abnormalities and other risk factors in patients with CHD.
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PMID:Clinical perspectives on primary and secondary prevention of coronary atherosclerosis. 767 95

Patients with non-insulin-dependent diabetes mellitus (NIDDM) have a greater risk of developing coronary heart disease than would be expected from a similar degree of hyperlipidemia in nondiabetic populations. Accelerated transfer of cholesteryl esters (CET) from high-density lipoprotein (HDL) to low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL), a process that is associated with atherosclerosis, may be a possible explanation for this. CET, plasma lipoprotein concentration, and mass in the fasting and postprandial state have been examined in 31 hyperlipidemic patients with NIDDM before and after 8 weeks of treatment with the hydroxymethylglutaryl (HMG)-coenzyme A (CoA) reductase inhibitor pravastatin in a double-blind, placebo-controlled, parallel group study. Body mass index, glycemic control, and blood pressure remained unaltered during the study period. Compared with placebo, pravastatin decreased fasting serum cholesterol (P < 0.001) and LDL cholesterol (P < 0.002) levels. The high basal CET (34.4 +/- 13.1 nmol.ml-1.h-1) was decreased significantly by pravastatin treatment (27.5 +/- 13.7 nmol.ml-1.h-1, P = 0.013). There was a fall in the total cholesterol, free cholesterol, and phospholipid content of the Sf 0-12, 20-60, and 60-400 lipoproteins (all P = 0.001). Lecithin: cholesterol acyl transferase activity was not altered. The postprandial increase in VLDL cholesterol 5 h after a standardized mixed meal was attenuated after pravastatin treatment (P = 0.011). Inhibition of hepatic cholesterol synthesis with an HMG-CoA reductase inhibitor in hyperlipidemic patients with NIDDM decreased serum cholesterol content of triglyceride-rich lipoprotein, thereby decreasing the transfer of cholesteryl ester from HDL to LDL and VLDL.
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PMID:Effect of treatment with a hydroxymethylglutaryl coenzyme A reductase inhibitor on fasting and postprandial plasma lipoproteins and cholesteryl ester transfer activity in patients with NIDDM. 769 16

The effects of administration of pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, on hepatic cholesterol 7 alpha-hydroxylase and acyl-coenzyme A: cholesterol acyltransferase (ACAT) activities and bile lipid secretion were investigated in Syrian golden hamsters. Continuous administration of pravastatin induced no significant changes in hepatic cholesterol content, ACAT and cholesterol 7 alpha-hydroxylase activities, or bile lipid and acid composition. Abrupt withdrawal of pravastatin induced increases in hepatic cholesterol content and ACAT activity and no change in hepatic cholesterol 7 alpha-hydroxylase activity, and increased cholesterol saturation in bile. Hepatic cholesterol 7 alpha-hydroxylase activity paralleled hepatic mRNA levels of this enzyme. These results suggest that a change in hepatic cholesterol metabolism induced by continuous administration of pravastatin maintains a constant net balance of hepatic cholesterol content. In addition, the drug has no deleterious influence on metabolism of bile lipids and acids and related enzymes, except for a transient increase in cholesterol saturation in bile induced by an inappropriate increase in hepatic cholesterol content and a lack of response of cholesterol 7 alpha-hydroxylase activity to changes in hepatic cholesterol content upon abrupt withdrawal of pravastatin.
Atherosclerosis 1994 Dec
PMID:Effect of pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, on hepatic cholesterol 7 alpha-hydroxylase, acyl-coenzyme A: cholesterol acyltransferase, and bile lipid secretion in the hamster with intact enterohepatic circulation. 771 20

The effect of l-triiodothyronine on 3-hydroxy-3-methylglutaryl CoA (HMG CoA) reductase activity was measured in cultured skin fibroblasts from patients with homozygous familial hypercholesterolemia (FH). The tested strains were obtained from 13 receptor-negative and 6 receptor-defective type homozygotes and 3 heterozygotes. Eleven out of 19 strains of cultured fibroblasts from FH homozygotes demonstrated high levels of the HMG CoA reductase activity when l-triiodothyronine was present in the culture medium. All the 11 strains that responded to l-triiodothyronine were the receptor-negative type in which the binding of LDL on the cell surface was completely lacking. Two receptor-negative type strains showed no response to the addition of l-triiodothyronine. In these strains, partially active receptors were synthesized and rapidly degraded. The effect of l-triiodothyronine on HMG CoA reductase was abolished by cycloheximide, and not by actinomycin D. Furthermore, the effect was abolished by the pre-loading of the cells with free cholesterol. The results indicate that the effect of l-triiodothyronine on HMG CoA reductase activity was a post-transcriptional event, required de novo protein synthesis, and was successful only when cholesterol was depleted from the cells. The difference in the responsiveness of HMG CoA reductase activity to l-triiodothyronine treatment can be utilized to judge the state of impairment of LDL-receptors in the FH homozygote from the viewpoint of ability to incorporate cholesterol into the cells.
Atherosclerosis 1995 Feb
PMID:Response of 3-hydroxy-3-methylglutaryl CoA reductase to l-triiodothyronine in cultured fibroblasts from FH homozygotes. 775 59

Atherosclerotic lesion development was assessed in the thoracic aorta and chronically denuded iliac-femoral artery of hypercholesterolemic New Zealand White rabbits using inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase which have previously been shown to possess varying degrees of hepatoselectivity in rats. Atorvastatin, previously known as CI-981 (2.5 mg/kg), PD135022 (1.0 mg/kg), simvastatin (2.5 mg/kg), lovastatin (2.5 mg/kg), PD134965 (1.0 mg/kg), pravastatin (2.5 mg/kg) and BMY22089 (2.5 mg/kg) were added to a 0.5% cholesterol, 3% peanut, 3% coconut oil diet and fed for 8 weeks. Although reductions in plasma total cholesterol of 27% to 60%, VLDL-cholesterol of 31% to 71% and plasma total cholesterol exposure of 37% to 43% were obtained, no correlation between these parameters and vascular lipid content, lesion size or monocyte-macrophage content was noted. Iliac-femoral lipid content was unchanged; however, atorvastatin and simvastatin significantly reduced the cholesterol content of the thoracic aorta by 45%-62%. Atorvastatin and PD135022 reduced the size of the iliac-femoral lesion by 67% and monocyte-macrophage content by 72%. Simvastatin, lovastatin and PD134965 decreased the monocyte-macrophage content; however, lesion size was unchanged. Pravastatin and BMY22089 had no effect on lesion size or content. No compound significantly reduced the extent of thoracic aortic lesions. We concluded that changes in plasma lipids and lipoproteins noted with the various HMG-CoA reductase inhibitors did not account for the beneficial effect on atherosclerotic lesion development. The antiatherosclerotic potential of the HMG-CoA reductase inhibitors was compound-specific and clearly not a class effect.
Atherosclerosis 1994 Nov
PMID:Antiatherosclerotic activity of inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase in cholesterol-fed rabbits: a biochemical and morphological evaluation. 784 Aug 8

Twelve men and thirteen women with hypercholesterolaemia participated in a 20-week controlled cross-over trial to assess the interaction between dietary fat intake, gender and an HMGCoA reductase inhibitor, simvastatin. Subjects were matched for total cholesterol, age, body mass index (BMI) and plasma triglyceride. Gender-drug interactions were noted with men demonstrating only a 27% fall in LDL cholesterol with simvastatin when consuming a high fat (40% energy) diet compared to women with a 35% fall. In men, the lowest LDL/HDL ratio was achieved with simvastatin on a low fat diet (22% energy). Gender differences in the effect of simvastatin on HDL were confined to HDL3 cholesterol, although the drug raised HDL2 in both sexes on the low fat diet. Simvastatin was responsible for an 11% increase in HDL3 cholesterol in men particularly when on a low fat diet but did not affect HDL3 in women. An important diet-drug interaction was seen in triglyceride response, with a lowering of 17%-20% only when subjects were on a low fat diet. There was a gender difference in response to dietary fat change with men demonstrating a 19% decrease in triglycerides with dietary fat reduction while on simvastatin, whereas women showed a 9% increase which did not reach significance. Men also responded more favourably to dietary fat reduction with at least two-fold greater falls in plasma cholesterol than was seen in women.(ABSTRACT TRUNCATED AT 250 WORDS)
Atherosclerosis 1994 Sep 30
PMID:Gender and diet interactions with simvastatin treatment. 785 67

To establish whether lovastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, exhibits a specific effect on apolipoprotein (apo) A- and apoB-containing lipoproteins, 63 subjects, a subset of the 270 Monitored Atherosclerosis Regression Study (MARS) patients with hypercholesterolemia (190 to 295 mg/dL) and documented coronary artery disease, were randomized into either lovastatin 40 mg twice daily or matching placebo tablets twice daily. Both groups consumed a diet containing 27% calories as fat (polyunsaturated fat/saturated fat ratio, 2.85) and a daily cholesterol intake of less than 250 mg. The plasma lipid and apolipoprotein profiles were determined at the time of randomization and after 2 years of treatment, and the levels of apoA- and apoB-containing lipoprotein families were measured after 2 years of treatment. After this treatment period, the drug group was characterized in comparison with the placebo group by significantly reduced levels of total cholesterol (33%), triglycerides (30%), very-low-density lipoprotein cholesterol (36%), low-density lipoprotein cholesterol (43%), apoB (36%), apoC-III (18%), and apoE (17%) and slightly but insignificantly increased levels of high-density lipoprotein cholesterol (6%) and apoA-I (1%). The 2-year levels of lipoprotein containing apoA-I but no apoA-II (LpA-I) and lipoprotein containing both apoA-I and apoA-II (LpA-I/A-II) particles separated by immunoaffinity chromatography on an anti-apoA-II immunosorber did not differ between the two treatment groups. However, the apoB-containing lipoprotein (Lp) families defined by apolipoprotein composition and separated by immunoaffinity chromatography on anti-apoA-II and anti-apoC-III immunosorbers were affected in a selective manner.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of lovastatin on ApoA- and ApoB-containing lipoproteins. Families in a subpopulation of patients participating in the Monitored Atherosclerosis Regression Study (MARS). 798 Nov 78

Patients with primary hypercholesterolemia and established coronary artery disease (CAD) with additional associated risk factors for atherosclerosis are considered for lipid-lowering drug therapy at lower levels of total and/or low-density lipoprotein cholesterol (LDL-C) than are patients with isolated hypercholesterolemia. As regards prevention of cardiovascular morbid events, high-risk patients are expected to receive the most benefit from lipid-lowering treatment. Thus, it is of interest to evaluate the efficacy, safety, and tolerability of the new lipid-lowering agent fluvastatin, a new, wholly synthetic 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor, in patients at high risk. A retrospective analysis was based on data from controlled clinical trials in which 1,815 patients were treated with fluvastatin at a daily dose of > or = 20 mg and 783 patients received placebo. Of the fluvastatin-treated patients, 328 (18.1%) had CAD compared with 136 (17.4%) patients taking placebo. Within these groups, 186 fluvastatin patients and 75 placebo patients had at least one of the following additional risk factors: hypertension, obesity, and/or fasting blood glucose levels above the upper limit of normal (ULN). Patients at high risk, as defined above, were compared with patients without CAD or any risk factors (fluvastatin, n = 837; placebo, n = 375). The effect of 40 mg of fluvastatin on LDL and high-density lipoprotein cholesterol (HDL-C), and triglycerides tended to be enhanced in patients at high risk (HR) compared with those at low risk (LR). Changes from baseline in HR patients were: LDL-C, -26.6%; HDL-C, 6.4%; triglycerides, -13%. Changes in LR patients were: LDL-C, -24.8%; HDL-C, 4.4%; triglycerides, -6%. All of these changes were highly significant (0.001 < p < 0.01). No patient in the HR group experienced a confirmed (measured on two consecutive occasions) increase > 3 x ULN in aspartate (ASAT) or alanine (ALAT) aminotransferases, nor any notable increases in creatine kinase > 10 x ULN. The tolerability of fluvastatin, as assessed by analysis of adverse events, was not consistently influenced by concomitant high risk. This exploratory analysis of the efficacy and safety profile of fluvastatin in patients at high risk for atherosclerosis suggests that such treatment is efficacious, safe, and well tolerated. The observed tendency toward an improved efficacy in the high-risk group will need further confirmation using data from prospective studies in such patients.
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PMID:Fluvastatin in primary hypercholesterolemia: efficacy and safety in patients at high risk. An analysis of a clinical trial database. 801 71


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