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)

Conflicting results have been published during the past few years regarding the physiologic modes of action of the hydroxymethylglutaryl-CoA (HMG-CoA) reductase inhibitors, generally referred to as statins, using standard doses. Three mechanisms have been described: increased LDL catabolic rate, increased removal of LDL precursors resulting in decreased LDL production and decreased VLDL production. The physiologic effects of statins seem to depend on the underlying pathology of the disorders under therapy. More recent data using either the more potent atorvastatin or larger doses of previously available statins (e.g. simvastatin 80-160 mg/day), suggest that both the potency of the statins and the underlying pathopHysiology are important in determining the predominant physiologic responses of patients. To understand physiologic responses more completely, drug-dose-physiologic response curves of apo B kinetics in various groups of patients are needed. Simultaneous studies of apo B, triglycerides and cholesterol metabolism are also needed and are currently feasible.
Atherosclerosis 1998 Dec
PMID:Metabolic modes of action of the statins in the hyperlipoproteinemias. 986 69

Hydroxymethylglutaryl-Coenzyme A (HMG-CoA) reductase inhibitors were shown to be effective in primary and secondary prevention of coronary heart disease. The beneficial effect of statins is generally attributed to their cholesterol lowering activity. However recent work points to additional cholesterol independent effects of these drugs on cellular signal transduction. In this study it was investigated whether HMG-CoA reductase inhibition could affect induction of the transcription factors c-Jun and c-Fos in smooth muscle cells, which play an important role in atherogenesis. SMC were preincubated for 12 h with or without lovastatin (5 microM) and subsequently stimulated with platelet derived growth factor (PDGF, 10 ng/ml) or angiotensin II (0.1 microM) for 1, 2, 4 and 12 h or with phorbol myristate acetate (100 pM) for 2 h. Stimulation in the absence of the HMG-CoA reductase inhibitor led to a significant induction of c-Jun and c-Fos. Lovastatin inhibited, PDGF-, angiotensin II- and PMA-mediated induction. Concomitant addition of mevalonate, farnesylpyrophosphate and geranylgeranylpyrophosphate prevented the effects of HMG-CoA reductase inhibition resulting in rescued expression of c-Jun and c-Fos. The suppression of these transcription factors was associated with a complete growth arrest. Viability was not affected by pretreatment with the HMG-CoA reductase inhibitor. The data demonstrate that lovastatin can suppress PDGF- and angiotensin II-mediated induction of c-Jun and c-Fos protein in human SMC. This inhibitory effect may prevent activation of numerous growth factor- and cell cycle- genes. Whether these findings contribute to the effects of statins in atherosclerosis remains to be further investigated.
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PMID:Effects of HMG-CoA reductase inhibition on PDGF- and angiotensin II- mediated signal transduction: suppression of c-Jun and c-Fos in human smooth muscle cells in vitro. 1020 88

Despite clear and consistent clinical-trial evidence that secondary-prevention medical therapies reduce mortality in patients with established coronary artery disease, these therapies are underutilized in patients receiving conventional care. To address this issue, a Cardiac Hospitalization Atherosclerosis Management Program (CHAMP) focused on initiation of aspirin, cholesterol-lowering medication (3-hydroxy-3-methylglutaryl-coenzyme A [HMG-CoA] reductase inhibitor titrated to achieve low-density lipoprotein [LDL] cholesterol < 100 mg/dL), beta-blocker, and angiotensin-converting enzyme (ACE)-inhibitor therapy in conjunction with diet and exercise counseling before hospital discharge in patients with established coronary artery disease was designed and implemented at the University of California Los Angeles (UCLA) Medical Center starting in 1994. This treatment program was based on the hypothesis that initiation of therapy in the hospital setting would result in higher utilization rates both at the time of discharge and during longer-term follow-up. Implementation of this program involved the use of a focused treatment guideline, standardized admission orders, educational lectures by local thought leaders, and tracking/reporting of treatment rates. To assess the impact of the program, treatment rates and clinical outcome were compared in patients discharged in the 2-year periods before and after CHAMP was implemented. Hospital-based treatment protocols such as CHAMP have the potential to significantly increase treatment utilization of therapies previously demonstrated to improve survival and thus substantially improve the outcome of the 2 million patients diagnosed and hospitalized each year with coronary artery disease.
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PMID:Rationale and design of the Cardiac Hospitalization Atherosclerosis Management Program at the University of California Los Angeles. 1069 2

Statins are lipid-lowering agents which act by inhibition of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase. This enzyme is responsible for the conversion of HMG-CoA to mevalonate. Products of mevalonate metabolism are critical for several cellular processes of eukaryotic cells, and inhibition of the mevalonate pathway by statins has pleiotropic effects. It has been reported that statins inhibit the migration and proliferation of vascular smooth cells (VSMCs) and macrophages, decrease interleukin-6 and inducible nitric oxide synthase expression in VSMCs, improve endothelial function and up-regulate endothelial nitric oxide synthase expression. The above effects of statins are independent of plasma cholesterol levels, and are completely blocked by exogenous mevalonate and some isoprenoids. These findings suggest that, in addition to their effects on plasma lipids, statins exert direct antiatherosclerotic effects on the cells primarily involved in atherosclerosis.
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PMID:Direct effects of statins on cells primarily involved in atherosclerosis. 1077 Feb 67

The results of the large trials with the inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase (or statins) in terms of clinical benefits in patients with coronary artery disease indicate that these drugs act in a complex way on several pathways involved in the atherosclerotic process. Beyond their lipid-lowering activity, statins appear to modify many characteristics of the arterial wall, resulting in protection against the progression of plaque growth and/or the precipitation of acute events. The so called "pleiotropic" effects of statins, such as the restoration of endothelial activity, the antioxidant potential or the antiproliferative effect on smooth muscle cells, have been investigated mainly in in vitro experiments. In the near future, it will be necessary to unravel the biological significance and the clinical relevance of these effects, which also involve other pathological conditions such as cancer and osteoporosis. Furthermore, lessons from the trials with statins have allowed a better understanding of the mechanisms leading to atherosclerosis which is now considered as an inflammatory process affecting the vascular wall. This has opened new perspectives in the search for the development of newer and more targeted anti-atherogenic drugs.
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PMID:[Atherosclerosis in light of the evidence from large statin trials]. 1084 99

The underlying disorder in the vast majority of cases of cardiovascular disease is atherosclerosis, for which low-density lipoprotein cholesterol is recognized as a major risk factor. Data from epidemiologic studies have suggested that lower cholesterol levels are associated with a lower overall risk of morbidity and mortality due to coronary heart disease. Numerous clinical trials with lipid-lowering agents support these epidemiologic data. Of these, studies with the HMG-CoA (3-hydroxy 3-methylglutaryl coenzyme A) reductase inhibitors, or statins, have shown the greatest lipid-lowering effects. Data from recent trials such as the Atorvastatin Versus Revascularization Treatment contribute to a growing body of evidence that suggests that aggressive reduction of cholesterol can yield additional clinical benefits above and beyond that observed with less robust treatment regimens. Aggressive cholesterol-lowering strategies have the potential therefore to have a significant impact on levels of atherosclerotic disease throughout the westernized world. Such effects argue in favor of renaming the entire class of drugs as anti- atherosclerotic rather than lipid-lowering agents.
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PMID:Implications of the atorvastatin versus revascularization treatment (AVERT) study for the clinician. 1098 Sep 11

Angiotensin II mediates most of the biological effects of the renin-angiotensin system (RAS), such as vasoconstriction and cell proliferation, via stimulation of the angiotensin II type 1 (AT1) receptor. The AT1 receptor plays a central role in the pathogenesis of atherosclerosis and hypertension. In parallel, hypercholesterolaemia is a major risk factor for the development and progression of cardiovascular diseases. The underlying molecular events, however, are understood only partially. An important mechanism may be the interaction between hypercholesterolaemia and AT1 receptor expression in vascular tissue. Low-density lipoprotein (LDL) cholesterol leads to a profound increase in AT1 receptor expression in cultured vascular smooth muscle cells as well as in hypercholesterolaemic rabbits. This up-regulation is associated with an enhanced functional response upon stimulation with angiotensin II. Over-expression of the vascular AT1 receptor can also be observed in hypercholesterolaemic men and is prevented by treatment with 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors. These findings may explain why hypercholesterolaemia is frequently associated with hypertension and why blockade of the RAS attenuates the progression of atherosclerosis.
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PMID:Angiotensin AT1 receptor over-expression in hypercholesterolaemia. 1102 85

Lifibrol (4-(4'-tert. butylphenyl)-1-(4'-carboxyphenoxy)-2-butanol) is a new hypocholesterolemic compound; it effectively lowers low density lipoprotein (LDL) cholesterol. We studied the effects of lifibrol on the cholesterol metabolism of cultured cells. In the hepatoma cell line HepG2, Lifibrol decreased the formation of sterols from [14C]-acetic acid by approximately 25%. Similar to lovastatin, lifibrol had no effect on the synthesis of sterols from [14C]-mevalonic acid. Lifibrol did not inhibit 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase. Instead, cholesterol synthesis inhibition by lifibrol was entirely accounted for by competitive inhibition of HMG-CoA synthase. Lifibrol enhanced the cellular binding, uptake, and degradation of LDL in cultured cells in a dose dependent fashion. The stimulation of LDL receptors was significantly stronger than expected from the effect of lifibrol on sterol synthesis. In parallel, lifibrol increased the amount of immunologically detectable receptor protein. Stimulation of LDL receptor mediated endocytosis was observed both in the presence and in the absence of cholesterol-containing lipoproteins. In the absence of an extracellular source of cholesterol, both lifibrol and lovastatin induced microsomal HMG-CoA reductase. Co-incubation with LDL was sufficient to suppress the lifibrol mediated increase in reductase activity, indicating that lifibrol does not affect the production of the non-sterol derivative(s) which are thought to regulate HMG-CoA reductase activity at the post-transcriptional level. Considered together, the data suggest that the hypolipidemic action of lifibrol may, at least in part, be mediated by sterol-independent stimulation of the LDL receptor pathway. A potential advantage of lifibrol is that therapeutic concentrations do not interfere with the production of mevalonate which is required not only to synthesize sterols but also as a precursor of electron transport moieties, glycoproteins and farnesylated proteins.
Atherosclerosis 2000 Nov
PMID:The effects of lifibrol (K12.148) on the cholesterol metabolism of cultured cells: evidence for sterol independent stimulation of the LDL receptor pathway. 1105 1

The major cause of morbidity and mortality associated with coronary atherosclerosis is plaque rupture, which often results in one of the acute coronary syndromes: unstable angina, non-Q-wave myocardial infarction (MI), or Q-wave MI. Plaque rupture may be attributable to the thickness of the overlying fibrous cap; thinner plaques are more likely to rupture. It appears that the presence of inflammation is a significant contributor to rupture. Acute-phase treatments are highly efficacious, but secondary prevention, often overlooked, also is life-saving. Diet, exercise, and medications are the interventions available for secondary prevention. Four classes of medications--aspirin, beta blockers, angiotensin-converting enzyme (ACE) inhibitors, and 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins)--are also used in this setting with a high degree of success in reducing mortality and morbidity. Numerous studies have demonstrated a 30-50% reduction in mortality with aspirin. The reduction in mortality achieved with beta blockers in studies of patients after myocardial infarction are 15-50%. ACE inhibitors significantly reduce the risk of death from myocardial infarction in patients with coronary artery disease with or without myocardial infarction. Statins are beneficial even in patients whose cholesterol level is low to normal. Patients who were discharged on a statin showed a 50% reduction in mortality over those who did not receive statin therapy independent of lipid level. C-reactive protein, a marker of inflammation, is predictive of mortality, as are age and ejection fraction. Statins may be anti-inflammatory in addition to their lipid-lowering effect. Secondary-prevention strategies such as case management, electronic discharge prompting, better communication between referring physicians and cardiologists, and patient education may also have positive effects on after-discharge morbidity and mortality.
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PMID:Post-hospitalization management of high-risk coronary patients. 1107 26

Since the demonstration of the obligatory role of the endothelium in arterial relaxation by Furchgott and Zawadzki (1980), there has been great interest in the role of the endothelium in vascular disease. Apart from endothelium-dependent vasodilation, other important functions of the endothelium have now been studied, that is, the regulation of adhesion and infiltration of leukocytes and inhibition of platelet adhesion and aggregation. Many functions of the endothelium are influenced by nitric oxide (NO), which is synthesized by endothelial NO synthase. Endothelial dysfunction in hypercholesterolemic patients is in large part due to a reduced bioavailability of NO. Multiple factors contribute to this, including increased inactivation of NO by radicals and inhibition of NO formation by different mechanisms. The functional implications of endothelial dysfunction are not completely defined. However, recent studies suggest that endothelial dysfunction contributes to myocardial perfusion abnormalities. Furthermore, endothelial dysfunction may play an important role with respect to development and progression of atherosclerosis because the endothelium is involved in the regulation of key events of the atherosclerotic process. Endothelial dysfunction in hypercholesterolemia is reversible by cholesterol-lowering treatment, that is treatment with HMG-CoA-reductase inhibitors. First experimental data suggest that maneuvers that increase the bioavailability of NO in hypercholesterolemia may even result in regression of preexisting atherosclerotic lesions.
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PMID:Endothelial dysfunction in hypercholesterolemia: mechanisms, pathophysiological importance, and therapeutic interventions. 1112 9


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