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)

Pravastatin is a new lipid-lowering drug belonging to the class of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase inhibitors. Since 1986, more than 15,000 patients have received pravastatin in sponsored clinical research trials with more than 21,000 cumulative patient-years of exposure to the drug. Analysis of long-term follow-up data from 1142 patients participating between 1986 and 1990 in six core randomized clinical trials in the United States confirms the favorable safety profile of pravastatin. Rash, gastrointestinal complaints, musculoskeletal pain, and elevations in liver transaminase levels, whether or not attributed to treatment, were the most common reasons for patients withdrawing from these trials. Ophthalmologic monitoring revealed no adverse effects on the crystalline lens. Safety assessments continue for two core trials in more than 400 patients with up to 7 years of continuous follow-up. The effects of pravastatin on serum cholesterol levels are not influenced by the age, sex, weight, or initial cholesterol level of the patient. Vitamin E, A, and D metabolism remain normal during treatment. Combination therapy with pravastatin and bile-acid-binding resins or niacin is well tolerated, with additive effects on low-density lipoprotein cholesterol. There is limited experience with the combination of pravastatin and gemfibrozil or cyclosporine. An ongoing arteriosclerosis research program with more than 21,000 patients enrolled will further define the long-term safety of pravastatin and its effects on atherosclerosis progression, as well as its role in the primary and secondary prevention of coronary heart disease.
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PMID:Long-term experience with pravastatin in clinical research trials. 845 55

Five classes of lipid-lowering drugs are approved by the Food and Drug Administration (FDA) for use in the United States: nicotinic acid, bile acid sequestrants, fibric acid derivatives, reductase inhibitors, and probucol. None of the agents has an antiatherosclerotic indication. Cholestyramine and gemfibrozil have received indications for preventing complications of atherosclerosis, namely, myocardial infarction and coronary artery disease death. Foreseeable pharmacological strategies to reduce lipid-related cardiovascular risk might be divided into three categories. First, the present approach of lowering lipid and lipoprotein concentrations might be extended through modification of available agents (e.g., a more potent or soluble bile acid resin) or development of agents of novel mechanism (e.g., acyl-CoA:cholesterol acyltransferase [ACAT] inhibition or inhibition of cholesterol biosynthesis at a step other than HMG-CoA reductase). Second, blood lipids could be directly addressed outside of lipid-lowering strategies. Raising high density lipoprotein (HDL) cholesterol levels has not been fully explored, or the target might be modification of the lipoproteins themselves rather than their concentrations. Areas of particular interest in the latter regard are hepatic lipase activity, cholesteryl ester transfer protein activity, and differences between oxidized or otherwise modified low density lipoprotein (LDL) particles and normal LDL. Third, it may be possible to directly lessen the atherosclerotic potential of the vessel wall (e.g., through protecting it from the effects of certain growth factors or altering its state of relaxation.
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PMID:Dyslipidemia and atherosclerosis. A forecast of pharmaceutical approaches. 846 81

The lesions of atherosclerosis represent a protective, inflammatory-fibroproliferative response against the different agents that can cause the disease. If the injury continues chronically over a sufficiently long period of time, and if opportunity is not given for restitution of normal architecture in the artery wall, lesions may progress to a point at which clinical sequelae develop. On the other hand, as demonstrated by Brown et al, Kane et al, and Blankenhorn et al, the advanced lesions of atherosclerosis can be shown to regress. A quantitative, statistical analysis of angiograms in patients who are aggressively treated with lipid-lowering agents, such as HMGCoA reductase inhibitors has clearly shown this to be the case. Thus, it is entirely conceivable that this chronic, excessive, inflammatory, and fibroproliferative response can be reversed, given sufficient opportunity for the factors that have led to the endothelial and arterial wall injury causing these events to be taken into hand and modified.
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PMID:Atherosclerosis: current understanding of mechanisms and future strategies in therapy. 847 Feb 66

We have investigated the toxicity of the cholesterol oxidation products (oxysterols), 7 alpha-hydroxycholesterol, 7 beta-hydroxycholesterol, 7-ketocholesterol, 25-hydroxycholesterol and 26-hydroxycholesterol to human monocyte-macrophages in vitro. The 7-position derivatives are present in low density lipoprotein (LDL) oxidised with copper (II) sulphate and macrophages, and in extracts of human atherosclerotic lesions, which also contain 26-hydroxycholesterol. We have also assessed 25-hydroxycholesterol for toxicity because it has often been used in studies of 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase inhibition and LDL receptor down-regulation. Measurement of radioactivity release from monocyte-macrophages preloaded with tritiated adenine, as a means of assessing cytotoxicity that all the oxysterols showed time- and concentration-dependent toxicity. The cytotoxic potency of 26-hydroxycholesterol was the greatest. The 7-position derivatives also produced marked cell damage, though at higher concentrations than for 26-hydroxycholesterol. Of the oxysterols assessed, the toxicity of 25-hydroxycholesterol was the least. The cytotoxicity of 7 beta-hydroxycholesterol and 26-hydroxycholesterol was also shown using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) dye reduction assay which confirmed that 26-hydroxycholesterol was more toxic than 7 beta-hydroxycholesterol. Incubation of monocyte-macrophages with cholesterol added to the different oxysterols gave varying results. Cholesterol, which was not itself toxic, inhibited the toxicity of 25-hydroxycholesterol and 26-hydroxycholesterol, but the toxicity of the 7-position derivatives was not affected. The possible relevance of these molecules to the death of macrophages seen in atherosclerosis is discussed.
Atherosclerosis 1995 Nov
PMID:Toxicity of oxysterols to human monocyte-macrophages. 857 33

To date, lipid-lowering therapy appears to be the most effective medical intervention to retard progression of coronary atherosclerosis. In spite of promising experimental results, clinical trials completed so far have failed to demonstrate that calcium channel blockers (CCBs) alone influence the evolution of established coronary atherosclerosis. To assess whether the two therapies may have an additive or synergistic beneficial effect on human atherosclerosis, we reviewed in this regard the data of the angiographic Regression Growth Evaluation Statin Study (REGRESS) trial. REGRESS was designed to determine the effect of lipid-lowering therapy with pravastatin in symptomatic patients with normal to moderately raised cholesterol levels. Angiographically, with respect to the minimum obstruction diameter, in the pravastatin group, patients had on average 0.05 mm (95% confidence interval [CI]: 0.01-0.09) less progression if cotreated with CCBs compared with no CCB treatment, whereas in the placebo (no pravastatin) group, no effect of CCB treatment was observed (interaction test for differential effect of CCB treatment in patients with pravastatin compared with patients receiving placebo: P=.0016). With respect to the mean segment diameter, similar although not significant (P=.33) results were found. With respect to new lesion formation, in the pravastatin group, there were 50% (CI: 25-83) fewer patients with new angiographic lesions if cotreated with CCBs compared with no CCB cotreatment, whereas in the placebo (no pravastatin) group, no significant effect of CCB treatment was observed (interaction test: P=.0026). No beneficial effects of CCB treatment on clinical events were observed. Although the REGRESS trial was not designed to evaluate combination therapy, the results suggest strongly that addition of CCBs to 3-hydroxy-3-methyl-glutaryl-coenzyme reductase inhibitor therapy (pravastatin) acts synergistically in retarding the progression of established coronary atherosclerosis.
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PMID:Evidence for a synergistic effect of calcium channel blockers with lipid-lowering therapy in retarding progression of coronary atherosclerosis in symptomatic patients with normal to moderately raised cholesterol levels. The REGRESS Study Group. 863 Jun 69

Familial hypercholesterolemia is associated with premature coronary heart disease. In patients with familial hypercholesterolemia, monotherapy with hydroxymethylglutaril coenzyme. A reductase inhibitors rarely achieves the goal of desirable low-density lipoprotein levels. Epidemiological studies suggest that populations with a high dietary intake of marine n3 fatty acids are protected against coronary heart disease. Hepatic synthesis and secretion of very low density lipoproteins are reduced during fish oil supplementation while other effects on lipid and lipoprotein metabolism are controversial. Fourteen patients affected by familial heterozygous hypercholesterolemia on chronic treatment with simvastatin were enrolled in a double blind, placebo controlled, randomized crossover trial that evaluated the effect of fish oil ethyl ester (Esapent, 5.1 g/day) on lipid and lipoprotein serum concentrations. Total cholesterol, low density lipoprotein cholesterol, high density lipoprotein cholesterol, triglycerides, apoprotein B, apoprotein AI, lipoprotein (a) did not show any significant variation during the four week treatment period with fish oil ethyl ester. The present data suggest that the possible favourable influence of fish oil on the progression of atherosclerosis in these high-risk patients might involve mechanisms which are different from lipid metabolism.
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PMID:Fish oil supplementation in patients with heterozygous familial hypercholesterolemia. 865 Apr 28

Cholesterol is an essential component of all tissues, as it is a part of the structure of cell membranes, and it is an immediate precursor of a series of essential substances such as vitamins, steroid hormones, and bile acids. Under physiologic conditions, the intake and output of cholesterol in the organism is coordinated and balanced with the aim of guaranteeing the availability of adequate amounts of cholesterol to satisfy the needs of the different tissues (fig. 1). Under pathological conditions there is an imbalance between these mechanism, which leads to an increase in the circulating levels of cholesterol, leading to pathological processes such as hyperlipemias, atherosclerosis and bile stones. The liver plays a central role in the regulation of the homeostasis of cholesterol. The molecule enters the liver in the form of chylomicrons and low density lipoproteins (LDL), through lipoprotein receptors, and this is also the most important organ for the de novo biosynthesis of cholesterol from acetyl coenzyme A, by means of a cascade enzyme reaction in which the enzyme 3-hydroxy-3 methyl glutaryl CoA reductase (HMG-CoA) is the key of the entire process. Cholesterol is found in the liver in the form of cholesterol esters or as free cholesterol. The two most effective ways of eliminating body cholesterol are found in the liver, with the degradation of the compound to bile acids and the biliary secretion of cholesterol. The conversion to bile acids takes place through a series of enzymatic steps in which the formation of 7-alpha-hydroxycholesterol by the enzyme cholesterol 7-alpha-hydroxylase is the key of the process. The biliary secretion of cholesterol is 600 mg/day. Both the abundance and the universality of cholesterol in living things as its clinical implications emphasize the importance and interest of this compound.
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PMID:[Hepatic metabolism of cholesterol]. 870 15

Elevated plasma fibrinogen level is known to progress atherosclerosis and to be one of the risk factors for the occurrence of cardiovascular diseases. The objective of this study is to evaluate the changes in plasma fibrinogen level and blood rheology in patients with type II hyperlipoproteinemia before and after random administrations of HMG-CoA (3-hydroxy-e-methylglutaryl-cocarboxylase-A) reductase inhibitors, pravastatin sodium and simvastatin, and compare with results in normal subjects. Of a total of 28 patients with type II primary hyperlipoproteinemia with > 230 mg/dl fasting total plasma cholesterol, 16 patients (mean, 59.7 years old) were administered 10-15 mg/day of pravastatin sodium for an average of 10.2 weeks, and 12 patients (mean, 62.0 years old) were administered 5-10 mg/day of simvastatin for an average of 13.9 weeks. Patients were evaluated before and after drug administration and results were compared with those of 16 normal subjects of similar age (mean, 56.9 years old). Blood viscosities were measured using a cone-plate viscometer (Biorheolizer, BRL-1000, Japan). The following were measured before and after drug administration: whole blood viscosity at shear rates of 75-375 s-1, corrected blood viscosity at low (112.5 s-1) and high (225.0 s-1) shear rates for the standard hematocrit of 45%, plasma viscosity, hematocrit, total protein, serum albumin, and plasma fibrinogen. Total cholesterol level was significantly decreased (from 270 to 225, mg/dl, mean values; P < 0.0007) an average of 10.2 weeks after start of pravastatin sodium administration. In addition to the reductions of whole blood viscosity, at every shear rate examined, corrected blood viscosity, and plasma viscosity, plasma fibrinogen levels were significantly decreased (from 354 to 309 mg/dl, mean values; P < 0.0007) after start of pravastatin sodium administration. Fibrinogen level and blood rheology were not significantly changed after start of simvastatin administration despite similar significant reductions in total cholesterol level (from 260 to 207 mg/dl, mean values; P < 0.0001) to those in the case of pravastatin sodium. From the results, we conclude that administration of pravastatin sodium, but not simvastatin, reduced the plasma fibrinogen level and blood viscosities to normal levels in type II hyperlipoproteinemic patients while both drugs reduced total cholesterol level. The hydrophilicity and a small binding capacity with plasma protein of pravastatin sodium may be responsible in part for the beneficial hemorheologic effects observed in the patients with type II hyperlipoproteinemia. Further investigations should be conducted to confirm the findings observed.
Atherosclerosis 1996 May
PMID:Effects of pravastatin sodium and simvastatin on plasma fibrinogen level and blood rheology in type II hyperlipoproteinemia. 912 20

Oxidized low density lipoprotein (oxLDL) is known to be toxic to a variety of cell types, but relatively little is known about the toxic effects of oxLDL on vascular smooth muscle cells (SMC). We found that LDL oxidized by incubation with 5 microM cupric ions was toxic to cultured porcine SMC when administered at concentrations of 25 micrograms protein/ml and higher. The toxicity was demonstrated whether cells were proliferating or not, and was more evident in the presence of 0.4% lipoprotein-deficient serum than in 10%. Because of recent evidence that 7-ketocholesterol and 7-hydroxycholesterol are toxic species in copper-oxidized LDL, inhibition of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase was hypothesized as a mechanism of toxicity. However, mevalonic acid, the product of this enzyme, failed to protect against the toxicity of either oxLDL or the pure oxysterols. Alpha-tocopherol, alpha-tocopherol acetate, probucol, butylated hydroxytoluene, and deferoxamine provided partial protection to SMC exposed to oxLDL. These results suggested a toxic role for newly initiated lipid peroxidation, either in cells or in media oxLDL. Cellular lipid peroxidation appeared more likely, since no further oxidation of media oxLDL was demonstrated in the presence or absence of antioxidants. Overall, the results suggest that toxicity of copper-oxidized LDL for SMC is multifactorial and differs from the previously described toxicity of iron-oxidized LDL for fibroblasts.
Atherosclerosis 1995 Dec
PMID:Toxicity of oxidized low density lipoproteins for vascular smooth muscle cells and partial protection by antioxidants. 877 Mar 18

Development of atherosclerosis in diabetes patients is thought to be associated with high D-glucose-induced changes in vascular cell proliferation. This study was designed to investigate the intracellular mechanisms of altered proliferation in porcine aortic endothelial and smooth muscle cells under high D-glucose conditions. Two different technical approaches were used for determination of cell proliferation, a cell counting procedure and bromodeoxyuridine incorporation. D-Glucose diminished endothelial cell proliferation (30.3%) and increased smooth muscle cell proliferation (143%) in a dose-dependent manner. Neither D-mannitol, sucrose nor L-glucose mimicked the effect of D-glucose. Inhibition of D-glucose uptake into vascular cells by cytochalasin B prevented the effect of high D-glucose on cell proliferation. The aldose-reductase inhibitors, sorbinil and zopolrestat, little affected high D-glucose-attenuated endothelial cell proliferation, while the enhanced proliferation of smooth muscle cells was prevented by aldose-reductase inhibitors. Elevation of cellular glutathione levels yielded protection of both cell types from high D-glucose-mediated changes in cell proliferation, suggesting that high D-glucose may act via generation of oxidative species. Finally, aminoguanidine was shown to constitute a very potent inhibitor of D-glucose-induced dysfunction in vascular cell proliferation. These data suggest that high D-glucose-induced changes in cell proliferation of endothelial and smooth muscle cells are related to specific D-glucose uptake rather than hyperosmolality. Aldose-reductase seems to be mainly involved in the effect of high D-glucose only on smooth muscle cell proliferation, while in endothelial cells there is (are) other factor(s) in addition to the sorbitol pathway involved in high D-glucose-induced changes in cell proliferation.
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PMID:Intracellular mechanism of high D-glucose-induced modulation of vascular cell proliferation. 878 35


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