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)

It has been suggested that penile hypercoagulability predisposes to aging penile vascular changes and impotence, and that elevated thromboxane A2 during erection may contribute to hypercoagulability and atherosclerosis. Since the ratio of the prostacyclin concentration to the thromboxane A2 concentration is constantly maintained in normal hemostatic responses, an imbalance between thromboxane A2 and prostacyclin may be a factor to initiate vascular diseases and decrease blood flow. We assess the usefulness of the prostacyclin-to-thromboxane A2 ratio in penile blood during erection for diagnosis of arteriogenic impotence. The ratio in the arteriogenic impotence group was significantly lower (p less than 0.01) than in the psychogenic and venogenic impotence groups. Therefore, the prostacyclin-to-thromboxane A2 ratio seems to be useful to diagnose arteriogenic impotence.
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PMID:Prostacyclin-to-thromboxane A2 ratio in arteriogenic impotence. 223 31

The effects of low dose indomethacin therapy in primary prevention of diet-induced atherosclerosis of rhesus monkeys was studied. The parameters studied were serum cholesterol concentration, thromboxane A2 (T x B2), prostacyclin (6-keto-PGF1 alpha) in serum/plasma, and the extent and intensity of coronary atherosclerosis. Although indomethacin did not affect serum cholesterol, it reduced serum T x B2 significantly (P less than 0.01). Plasma 6-keto-PGF1 alpha was not restored to the pretreatment level. A significant protective role of the drug was noted as far as coronary atherosclerosis is concerned (P less than 0.01).
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PMID:Short-term therapy of atherosclerosis with low dose indomethacin: an experimental study. 225 17

In the submitted review the author deals with specific features of the coronary circulation, coronary reserve and importance of regulation of the tonus of the coronary arteries at their epicardiac course and the tonus at the arteriolar level. In the subsequent part the author deals systematically first with the nervous regulation incl. the basic importance of the alpha-adrenergic (vasoconstrictor) and beta-adrenergic (vaso-dilating) sympathomimetic component. He mentions also the importance of neuropeptides (neuropeptide Y and substance P). Attention is devoted to the importance of the endothelium and endothelial vasoactive substances in the control of circulation. The main representatives of substances with a vasodilatating action are the endothelial relaxation factor and prostacycline, as to vasoconstrictor substances it is endothelin, thromboxan A2 and some growth factors. The authors discuss also the mechanical component, i. e. the influence of the blood flow and viscosity on the tonus of the coronary arteries. Finally the author draws attention to the clinical importance of disorders of regulatory mechanism in atherosclerosis and some clinical entities.
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PMID:[Regulation of coronary circulation]. 225 78

Patients with chronic renal failure who undergo hemodialysis experience accelerated atherosclerosis and premature death. Since the end-metabolite, oxalic acid, accumulates in plasma in proportion to the severity of renal failure, we studied whether sodium oxalate (0 to 300 microM) is an endothelial toxin and, therefore, might enhance atherogenesis. Exposure to uremic levels of oxalate (greater than 30 microM) for 9 to 28 days depressed endothelial cell replication by 33% to 84% (mean +/- SD, 54% +/- 15.7%, n = 17 experiments, p = 0.002). In contrast, replication of fibroblasts exposed to 200 microM oxalate for 45 days was not inhibited. The inhibitory effect of oxalate on endothelial cell replication was both dose- and time-dependent (both p less than 0.0001) and was first detected 3 to 7 days after the initial exposure to oxalate. Further, the inhibitory effect was fully reversible upon removal of oxalate, but only if exposure was limited to 5 days or less. Sodium salts of other carboxylic acids (citric, succinic, glyoxylic, and malonic; 200 microM) as well as HCl (200 microM) did not suppress endothelial cell replication. Oxalate also inhibited endothelial cell migration but had no effect on basal, thrombin-induced, or arachidonate-induced prostacyclin production by endothelial cells. Exposure of endothelial cells to sodium oxalate (200 microM) for as little as 24 hours-a time period sufficient to induce delayed, transient inhibition of replication not detectable until approximately 1 week after exposure-inhibited incorporation of 3H-leucine into protein by 40% (p = 0.009). We conclude that sodium oxalate acts as a uremic toxin, inhibiting endothelial cell replication and migration, functions which may be important for constitutive inhibition of atherosclerosis.
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PMID:Uremic levels of oxalic acid suppress replication and migration of human endothelial cells. 231 57

Probucol, 4,4'-(isopropylidenedithio)bis(2,6-di-tert-butyl-phenol), has been shown to inhibit atherogenesis in genetically hypercholesterolemic (Watanabe) rabbits. Since atherosclerotic lesions contain macrophages capable of screting interleukin 1 (IL 1) and other cytokines that could contribute to the pathogenesis of the disease, we have investigated whether probucol affects IL 1 secretion. Resident peritoneal macrophages from mice dosed with probucol secreted 40-80% less IL 1 than macrophages from control animals when stimulated in vitro with lipopolysaccharide (LPS). The inhibitory effect of probucol was observed when IL 1 was assayed by the standard bioassay, the thymocyte proliferation assay, or a competitive IL 1 receptor binding assay. Probucol treatment had no effect on LPS-induced membrane IL 1 expression; secretion of tumor necrosis factor (TNF); Con A-induced splenic interleukin 2 (IL 2) and interleukin 3 (IL 3) release; and prostaglandin- or zymosan-induced secretion of prostacyclin, leukotriene C4, acid phosphatase, or superoxide anion. In contrast to the effect of oral administration, direct addition of probucol to macrophage cultures did not inhibit IL 1 release. Probucol administration did, however, inhibit the fall in serum zinc level induced by intravenous injection of LPS in zymosan-primed mice but had no effect on the LPS-induced increase in serum triglyceride levels, which indirectly confirms that probucol administration inhibits IL 1 but not TNF secretion. Paw granuloma induced in mice by heat-killed mycobacteria was inhibited by oral administration of probucol, an effect that may be attributable to inhibition of IL 1 secretion. Probucol neither reduced zymosan-induced liver granulomata in mice nor inhibited adjuvant-induced arthritis in rats. We suggest that inhibition of IL 1 secretion from macrophages by probucol contributes to its therapeutic effects in atherosclerosis and may also result in beneficial activity in some chronic inflammatory diseases.
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PMID:Ex vivo lipopolysaccharide-induced interleukin-1 secretion from murine peritoneal macrophages inhibited by probucol, a hypocholesterolemic agent with antioxidant properties. 231 80

The endothelium modulates coronary vascular tone by the release of endothelium-derived relaxing or contracting substances. The endothelium-derived relaxing factor has been identified as nitric oxide synthesized in endothelial cells from L-arginine. The endothelium can release other relaxing substances such as prostacyclin and a hyperpolarizing factor. Endothelin-1 is a potent vasoconstrictor peptide formed by endothelial cells, and is likely to be the physiologic antagonist of endothelium-derived relaxing factor. Other putative contracting factors include superoxide anions and products of arachidonic acid metabolism. Endothelium-derived relaxing factor is released spontaneously and in response to flow, platelet-derived products (that is, serotonin, thrombin and adenosine diphosphate) and certain autacoids (that is, acetylcholine, bradykinin, histamine, substance P, vasopressin, alpha-adrenergic agonists). A considerable heterogeneity of responses exists among vessels of different size from different anatomic origin and different species. Hypercholesterolemia, atherosclerosis, hypertension and myocardial ischemia or reperfusion, or both, impair endothelium-dependent relaxation. Under normal conditions, endothelium-derived relaxing factor appears to dominate the control of vascular tone of large and small coronary vessels, whereas in disease states, endothelium-derived contracting factors are released. Impairments of endothelial function may be important in the development of various forms of cardiovascular disease.
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PMID:Endothelial control of vascular tone in large and small coronary arteries. 240 18

The effects of the stable prostacyclin analogue iloprost, prostaglandin E1 and prostaglandin F2 alpha on sterol synthesis were investigated in freshly isolated human mononuclear leukocytes. Incubation of cells for 6 h in a medium containing lipid-depleted serum led to a 3-fold rise in the rate of sterol synthesis from [14C]acetate or tritiated water. Iloprost and prostaglandin E1 added in increasing concentrations at zero time resulted in an inhibition of the synthesis of sterols, the suppression being 50 and 55% at a concentration of 1 mumol/1, respectively. Both prostaglandins yielded a sigmoidal log dose-effect curve. In contrast, prostaglandin F2 alpha had no influence on sterol synthesis up to a concentration of 1 mumol/1. The action of the prostacyclin analogue and prostaglandin E1 on the relative rate of sterol synthesis was not immediate, since the prostaglandins had no effect when given at 6 h to the incubation medium, and the incorporation of [14C]acetate into sterols was measured thereafter. The results suggest that prostacyclin and prostaglandin E1 affect cholesterol synthesis and therefore may play a role in the regulation of cellular cholesterol homeostasis and in the development of atherosclerosis.
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PMID:The prostacyclin analogue iloprost and prostaglandin E1 suppress sterol synthesis in freshly isolated human mononuclear leukocytes. 240 73

Disturbances in the balance between the production of thromboxane A2 by the platelets and that of prostacyclin by the vessel wall may play a major role in disease and be a target for therapeutic agents. Acetylsalicylic acid, given in small doses, may inhibit the production of thromboxane A2 without affecting that of prostacyclin. Even if it reduces prostacyclin synthesis, the drug is beneficial as an antithrombotic agent, possibly because it has actions not related to inhibition of cyclooxygenase. Dazoxiben not only inhibits the production of thromboxane A2 by platelets, but also facilitates that of prostanoids, in part by diverting endoperoxides to the blood vessel wall and to leukocytes. Although reduced production of prostacyclin may contribute to the etiology of atherosclerosis, the blood vessel wall of hypercholesterolemic animals exhibits an increased production of prostacyclin. The latter has been given successfully in patients with accelerated turnover of platelets or with peripheral vascular disease. However, its very short t1/2 limits its practical use. The availability of stable prostacyclin derivates, such as ZK 36374, may bypass this problem.
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PMID:Pathological significance of the thromboxane-prostacyclin hypothesis. 240 92

The influence of red blood cells on spontaneous platelet aggregation (SPA) has been studied ex vivo. Platelet aggregation was quantified by measuring the fall in single platelet count using a new whole blood platelet counter. When aliquots of whole blood and autologous platelet rich plasma (PRP) were roller-mixed at 37 degrees C, a marked fall in platelet count occurred in whole blood due to SPA but platelet count remained almost unchanged in PRP. When blood from healthy young controls, aged 20-35 years, was compared with healthy old controls, aged 48-80 years, and patients with thrombotic complications, the extent of SPA was in the order: thrombotic patients greater than old controls greater than young controls. Prostacyclin and the new stable prostacyclin analogue Iloprost, at 8 nM effectively inhibited SPA. 2-Chloroadenosine (10 microM) which is an inhibitor of ADP-induced platelet aggregation was also an effective inhibitor of SPA. Acetylsalicylic acid (56 microM) and the thromboxane A2 receptor blocker BM13.177 (0.5 microM) only partially inhibited SPA. ADP from red blood cells is suspected to mediate red cell-induced SPA. However, the possibility that the red cells have an important physical role in SPA cannot be ruled out.
Atherosclerosis 1987 Aug
PMID:Red blood cells mediate spontaneous aggregation of platelets in whole blood. 244 48

The effect of lowering total plasma and low density lipoprotein (LDL) cholesterol in heterozygous familial hypercholesterolaemia type IIa (FH) on platelet function, thromboxane (TX) formation and platelet sensitivity against iloprost, a stable prostacyclin mimetic, was studied in platelet-rich plasma ex vivo. Seven FH patients were treated with cholestyramine (12 g day 1) for 8-11 months and were compared with eight untreated FH patients and 11 healthy control subjects. In comparison with platelets from healthy controls, platelets from untreated FH patients exhibited a significantly increased aggregation response and TX formation, and a reduced reactivity against inhibition of platelet aggregation by prostacyclin. Treatment with cholestyramine for 8-11 months resulted in a 21% reduction in total serum and LDL-cholesterol. This was not accompanied by any change in platelet hyperreactivity or TX formation. However, cholestyramine treatment normalized the platelet reactivity of FH patients against iloprost, being no more different from healthy controls. It is concluded that reduction in plasma cholesterol by cholestyramine results in normalization of the reduced platelet sensitivity against prostacyclin. This might contribute to beneficial effects of cholestyramine treatment in preventing thromboembolic complications of atherosclerosis.
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PMID:Cholestyramine treatment of type IIa hypercholesterolaemia normalizes platelet reactivity against prostacyclin. 245 63


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