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)

Calcium channel blockers (CCBs), which are used clinically for treatment of angina and hypertension, are known to inhibit calcium influx into arterial smooth muscle cells and thereby decrease smooth muscle cell contraction. In addition, they prevent cholesteryl ester (CE) accumulation, the hallmark of human atherosclerosis, in arteries of cholesterol-fed animals by cellular mechanisms that remain undefined. To assess whether CCBs enhance CE hydrolysis and reduce CE accumulation in human arterial cells, we measured activities of the CE metabolic cycle in aortic tissues that were stripped of endothelial cells and adventitia from 35 patients undergoing coronary artery bypass surgery. Patients who were treated with either nifedipine or diltiazem (n = 23) for several months demonstrated a threefold increase in arterial CE hydrolytic activities compared with untreated patients. This difference was independent of serum cholesterol levels, age, or treatment with other medications. No effects were observed on CE synthetic activity. Cyclic AMP levels in the aortic tissue of patients treated with CCBs were also significantly elevated twofold to threefold. In addition, both free and esterified cholesterol were significantly reduced in aortic tissue from patients taking CCBs compared with untreated patients. These data are the first to show that CCBs can increase CE hydrolysis in human aortic tissue by increasing intracellular cyclic AMP with resultant decrease in CE accumulation. Collectively, these findings support the hypothesis that CCBs can act as antiatherosclerotic agents in human tissue by mobilizing stored CE in the arterial wall.
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PMID:Calcium channel blockers enhance cholesteryl ester hydrolysis and decrease total cholesterol accumulation in human aortic tissue. 215 60

To evaluate the effect of hypertension on glycosaminoglycan (GAG) synthesis, cultured vascular smooth muscle cells (CVSMCs) from the aorta of spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) were exposed to centrifugal forces and catecholamines. GAG synthesis of CVSMCs was measured by the incorporation of [3H]glucosamine into GAGs which were secreted into the culture medium for 24 h. Basal level of GAG synthesis was much higher in SHR than in WKY, when expressed in terms of DNA contents. When exposed to centrifugal force, CVSMCs from rats of both strains synthesized more GAGs. GAG synthesis was enhanced by both noradrenaline (NA) and adrenaline (Ad) in WKY. The enhanced GAG synthesis in WKY by NA or Ad was prevented by pretreatment with propranolol, but not prazosin. In SHR, NA and Ad did not enhance GAG synthesis at this concentration of catecholamines. However, the effects of propranolol or prazosin on GAG synthesis in SHR, when incubated with either NA or Ad, were compatible with the phenomena observed in WKY. Adding dibutyryl cyclic AMP to the culture medium enhanced GAG synthesis in rats of both strains. These data suggest that not only the mechanical stress of high intra-arterial pressure but also beta receptor stimulation, via increasing cyclic AMP, enhance GAG synthesis of vascular smooth muscle cells in hypertension.
Atherosclerosis 1990 Aug
PMID:Effect of centrifugal force and catecholamines on glycosaminoglycans synthesis of vascular smooth muscle cells in culture. 224 93

Recent studies have revealed the important roles of platelets in atherogenesis via vascular injury. Our in vivo and in vitro studies clearly demonstrate that activated platelets directly inflict injury to vascular endothelial cells, which is associated with a decrease in intracellular cyclic AMP levels in vascular tissues. Antiplatelet therapy is clinically important not only for the prevention of thrombotic episodes but also for the prevention of vascular injury and atherosclerosis. A small dose of aspirin (80 mg) induces clinically hypoaggregativeness of platelets with concomitantly decreased levels of thromboxane A2 in plasma. Our clinical study involving more than 3 years of treatment with small doses of aspirin demonstrated favorable therapeutic effects characterized by hypoaggregation of platelets and increased levels of cAMP and 6-keto PGF1 alpha in plasma which will aid in the prevention of atherosclerosis.
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PMID:Antiplatelet therapy for atherosclerotic disorders. 224 48

The effects of dibutyryl cyclic AMP (db cAMP), cholera toxin, and methylisobutylxanthine on the content and metabolism of lipids in smooth muscle cells cultured from normal and atherosclerotic intima of human aorta have been studied. Db cAMP (0.1 mM) decreased the levels of triglycerides and esterified sterols 1.5-3-fold in cells cultured from fatty streaks and atherosclerotic plaques. Cholera toxin (100 micrograms/ml) and methylisobutylxanthine (0.1 mM) stimulated by 2-fold the cyclic AMP level in aortic smooth muscle cells and decreased the content of triglycerides and esterified sterols by 2-3-fold. Prolonged treatment with db cAMP and methylisobutylxanthine resulted in a fall in the intracellular phospholipids and free sterols. Using the labelled precursors, [3H]acetate and [14C]oleate, it was established that the agents increasing the intracellular cyclic AMP level inhibit the formation of sterols and fatty acids, impede the synthesis of phospholipids, triglycerides and esterified sterols, and stimulate their hydrolysis. The data demonstrate that cyclic AMP facilitates the regression of cellular lipoidosis by altering the intracellular lipid metabolism.
Atherosclerosis 1986 Oct
PMID:Effect of cyclic AMP on lipid accumulation and metabolism in human atherosclerotic aortic cells. 243 May 88

A primary culture of cells derived from uninvolved and atherosclerotic intima of human aorta was used to elucidate the role of cyclic nucleotides in atherogenesis. The cells cultured from fatty streaks and atherosclerotic plaques had a 2- to 8-fold lower cyclic AMP level and a 1.5- to 2-fold higher level of cyclic GMP compared with those of a grossly normal intima. Medial cells cultured from nonlesioned and atherosclerotic aortic segments showed no differences in the cyclic nucleotide concentrations. Reduction of the intracellular cyclic AMP with 2'-deoxyadenosine or a cyclic GMP elevation with its dibutyryl derivative, or liposomes containing cyclic GMP stimulated the uptake of [3H]thymidine and protein synthesis in the cells cultured from unaffected intima. On the contrary, a rise of the intracellular cyclic AMP caused by adenylate cyclase activators, a phosphodiesterase inhibitor, dibutyryl cyclic AMP, and liposomes containing cyclic AMP inhibited cell proliferation and protein synthesis. Elevation of the intracellular cyclic AMP stimulated the hydrolysis of lipids which led to reduction of lipid levels in the cells cultured from atherosclerotic lesions. The results of this study corroborate the existence of a relationship between the alterations of intracellular cyclic nucleotide levels and the metabolic disorders occurring in atherosclerosis.
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PMID:Cyclic nucleotides and atherosclerosis: studies in primary culture of human aortic cells. 244

The specific markers of platelet activation, e.g. platelet aggregation induced with ADP, AA and PAF as well as the levels of Beta-TG, TXB2, 6-keto-PGF1 alpha and cyclic AMP in the patients suffering from obliterative arteriosclerosis of the lower limbs were measured. It was found that these patients revealed hyperfunction of blood platelets expressed in increased sensitivity of platelets to ADP and PAF, increased levels of Beta-TG and TXB2 as well as decreased levels of 6-keto-PGF1 alpha and cyclic AMP. Obtained results support the concept that atherosclerosis consists of a wide-spread functional alteration of various types of cells.
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PMID:Blood platelet function in patients with obliterative arteriosclerosis of the lower limbs. 246 57

We performed an in vitro study to assess injury to vascular endothelial cells by platelets. Cultured endothelial cells isolated from fetal bovine aorta were used. Addition of human platelets, activated by collagen or lysed by sonication, to the culture dish resulted in dose- and time-dependent damage to the cells as estimated by [3H]adenine release. Analysis of [3H]adenine nucleotides by thin-layer chromatography on PEI-cellulose revealed decreased intracellular ATP content in the cells treated with platelet lysate. The medium contained AMP and adenosine, the latter increasing following the treatment of the cells. Of the substances released by the activated platelets, thromboxane A2 (TxA2) and serotonin caused cell damage. Platelet-derived growth factor (PDGF), however, did not damage the endothelial cells up to a concentration of 200 ng/ml. Pretreatment of the cells with methysergide (10(-6) M) or ONO 3708 (10(-5) M), a TxA2 antagonist, only partially prevented the damage, while ZK 36374 (10(-6) M), a prostacyclin analog, and 3-isobutyl-1-methylxanthine (IBMX; 10(-3) M), a phosphodiesterase inhibitor, potently inhibited injury. We conclude that the substances released from activated platelets may injure endothelial cells in an additive or synergistic manner and that agents which produce effects that elevate cyclic AMP levels may protect the cells from damage induced by the platelets.
Atherosclerosis 1989 Apr
PMID:In vitro study of vascular endothelial injury by activated platelets and its prevention. 254 23

Cyclic AMP and cyclic GMP content was measured in intima media of unaffected and atherosclerotic areas of human aorta in a short-term organ culture. It was demonstrated that during short-term cultivation the content of both cyclic nucleotides in tissues is constant. The cyclic AMP content in fatty streaks and atherosclerotic plaques is significantly (2 to 7-fold) lower than in unaffected intima. The cyclic GMP level in atherosclerotic lesions is 1.5 to 3-fold higher than in normal. The content of both cyclic nucleotides in the media underlying fatty streaks and atherosclerotic plaques is the same as in the normal tissue. The obtained data indicate serious disorders in the system of cyclic nucleotides during atherosclerosis.
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PMID:[The content of cyclic nucleotides in an organ culture of normal and atherosclerosis-affected human aorta]. 254 34

According to the response to injury hypothesis, endothelial migration and repair may play an important role in the initiation and progression of atherosclerosis. In this study, we examined the regulatory mechanisms of endothelial cell migration in vitro, using cultured endothelial cells from fetal bovine aortas. Dibutyryl cyclic AMP, 8-bromo cyclic GMP, and theophylline (each at concentrations of 10(-4) to 10(-3) M) inhibited the migration of endothelial cells. Migration was not significantly affected by the Ca2+ channel blockers diltiazem (10(-6) to 10(-4) M) and nicardipine (10(-6) to 10(-5) M) or by La3+ (10(-4) to 10(-3) M), an inorganic Ca2+-antagonist, TMB-8 (10(-6) to 5 x 10(-5) M), an intracellular Ca2+ blocker, or the calmodulin inhibitors W-7 (10(-6) to 5 x 10(-5) M) and trifluoperazine (10(-7) to 10(-5) M). At the extracellular Ca2+ concentrations of less than 0.2 mEq/l, the migration was inhibited significantly. In addition, migration was markedly suppressed by colchicine (10(-8) to 10(-5) M), an inhibitor of tubulin polymerization, and by cytochalasin B (10(-7) to 10(-5) M), an inhibitor of actin polymerization. These results suggest that cyclic nucleotides, such as cyclic AMP and GMP, may regulate the migration of vascular endothelial cells. Although a low concentration of extracellular Ca2+ is essential to their migration, participation of the intracellular Ca2+-calmodulin system was not evident in this study. It appears that the cytoskeletal system, including microtubules and microfilaments, is involved in the mechanisms of migration.
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PMID:Vascular endothelial cell migration in vitro roles of cyclic nucleotides, calcium ion and cytoskeletal system. 255 95

The effects of prostaglandin (PG) E1, PGE2, the stable prostacyclin analogue Iloprost, and PGF2 alpha on low density lipoprotein (LDL) receptor activity and cholesterol synthesis were investigated in freshly isolated human mononuclear leukocytes. Incubation of cells for up to 45 hr in a lipid-free medium resulted in an increase in the rate of cholesterol synthesis from [14C]acetate and the high affinity accumulation and degradation of 125I-labeled LDL. Addition of PGE1 in increasing concentrations to the incubation medium inhibited cholesterol synthesis and the specific accumulation and degradation of 125I-labeled LDL; at a concentration of 10 microM, the inhibitions were 61%, 70%, and 67%, respectively, after an incubation of 20 hr. The effects of PGE2 and Iloprost were similar. The action of the prostaglandins on LDL receptor activity appeared to be mediated by a decrease in the number of LDL receptors and not by a change in the binding affinity. The prostaglandins yielded sigmoidal log concentration-effect curves. In contrast, PGF2 alpha had no influence on cholesterol synthesis or LDL receptor activity up to a concentration of 10 microM. PGE1, PGE2, and Iloprost, but not PGF2 alpha, led to an increase in the concentration of intracellular cyclic AMP. Dibutyryl cyclic AMP mimicked the effects of the E-prostaglandins and Iloprost on the LDL receptor activity. The results suggest that PGE1, PGE2, and prostacyclin affect LDL receptor activity and cholesterol synthesis and, therefore, may play a role in the regulation of cholesterol homeostasis and in the development of atherosclerosis.
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PMID:Effects of prostaglandins on LDL receptor activity and cholesterol synthesis in freshly isolated human mononuclear leukocytes. 285 53


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