Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0151744 (myocardial ischemia)
 31,282 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Northwick Park Heart Study suggested that factor VII activity might be more strongly related to fatal than non-fatal events of ischaemic heart disease. We used polychotomous logistic regression to model simultaneously the probabilities of fatal events, non-fatal myocardial infarction, dying of causes other than ischaemic heart disease and of events, non-fatal myocardial infarction, dying of causes other than ischaemic heart disease and of event-free survival. We followed 1459 white men aged 40-64 at recruitment for a mean period of 16.1 years. Of these, 92 died of ischaemic heart disease, 100 experienced non-fatal myocardial infarction, 173 died of other causes, and 1094 men were alive. Factor VII activity was strongly related to fatal events of ischaemic heart disease but not to non-fatal events (p = 0.008). A difference of 1 SD in factor VII activity was associated with a difference of nearly 50% in the probability of dying of ischaemic heart disease, but with no difference for non-fatal myocardial infarction. This contrast was not seen for smoking, cholesterol, blood pressure, fibrinogen or factor VIII activity. High levels of VII activity may influence outcome at the time of plaque rupture and tissue factor release by enhancing thrombin production and thus fibrin deposition and platelet aggregability. The apparently differential effect of factor VII activity on fatal and non-fatal ischaemic heart disease may have important screening and prophylactic implications.
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PMID:Factor-VII activity and ischaemic heart disease: fatal and non-fatal events. 792 91

Oxidant stress to the endothelium is an important component of inflammatory processes involved in the pathogenesis of ischemic/reperfusion injury. The effects of acute oxidant exposure on cultured bovine coronary artery endothelial cell (BCA) functions including arachidonic acid metabolism, permeability, tissue factor expression, and viability were assessed after exposure of cells to the hydrogen peroxide-generating system of glucose-glucose oxidase (GO). GO markedly stimulated the synthesis of the arachidonic acid metabolites 15-hydroxyeicosatetraenoic acid (15-HETE) and prostacyclin (PGI2). Both sublethal and lethal concentrations of GO increased 15-HETE release from BCAs by as much as 15-fold. In contrast to 15-HETE, enhanced PGI2 synthesis occurred at concentrations of GO that did not injure the BCA monolayers, whereas lethal doses of GO had no stimulatory effect on PGI2 production. Moreover, the sublytic oxidant-induced stimulation of PGI2 synthesis in BCAs (50-fold) was significantly greater than that induced by other mediators or that observed in parallel studies with human umbilical vein endothelial cells. In vitro endothelial cell barrier function was determined by measuring iodine 125-labeled albumin clearance across confluent cell monolayers. GO increased cellular permeability in a concentration-dependent manner, although statistically significant increases were only observed at the highest (i.e., lethal) concentrations (C(alb) = 0.840 +/- 0.16 with 1.0 U/ml GO vs C(alb) = 0.24 +/- 0.02 in control cells). Finally, oxidant exposure did not induce BCA tissue factor activity at any concentration examined. These results suggest that oxidant exposure, as might occur during ischemic reperfusion, could affect subsequent coronary vascular responses by releasing the arachidonate metabolite 15-HETE, which can cause vasoconstriction as well as attract and activate leukocytes. In addition, oxidants may also modulate vascular reactivity by altering the release of the potent vasodilator and neutrophil modulator PGI2 as lower levels of oxidant generation stimulate its synthesis, whereas higher levels suppress PGI2 release. Thus the degree of oxidant stress may profoundly affect the endothelial synthesis and release of 15-HETE and PGI2, compounds with antagonist effects on vascular tone and neutrophil activation. Consequently the balance between oxidant-induced production of these mediators by the coronary endothelium may significantly affect the pathophysiology of myocardial ischemia and reperfusion injury.
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PMID:Oxidant exposure stimulates cultured coronary artery endothelial cells to release 15-HETE: differential effects on PGI2 and 15-HETE synthesis. 793 Aug 81

Although the majority of factor VII (FVII) circulates in the zymogen form, low levels of activated factor VII (FVIIa) have been postulated to exist in plasma and to serve a priming function for triggering of the clotting cascade. However, direct measurement of plasma FVIIa has not previously been possible. We have quantified plasma FVIIa levels using a novel, highly sensitive assay that is free from interference by FVII. Specificity of this clot-based assay results from the use of a mutant tissue factor that is selectively deficient in promoting FVII activation, but retains FVIIa cofactor function. In normal adults, FVIIa was found to be present in plasma (mean: 3.6 ng/mL) with considerable variation between individuals (range: 0.5 to 8.4 ng/mL). FVIIa levels were only loosely correlated with FVII coagulant activity, but were elevated in pregnancy and reduced with oral anticoagulant therapy. Incubation of plasma on ice in glass containers (cold activation) resulted in substantial FVIIa generation. Measurement of plasma forms of factor VII is of potential clinical importance because elevated FVII coagulant activity has been implicated as a significant risk predictor for ischemic heart disease. Clinically, this new assay will now permit direct assessment of the role of plasma FVIIa in thrombotic disorders.
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PMID:Quantitation of activated factor VII levels in plasma using a tissue factor mutant selectively deficient in promoting factor VII activation. 842 65

Factor VII (FVII) is a plasma vitamin K-dependent glycoprotein that plays an important role in the initiation of tissue factor-induced coagulation (extrinsic pathway of blood coagulation). An increase in FVII coagulant activity (FVIIc) has been proposed as an independent risk factor for coronary artery disease. Recently, the coagulation assay using soluble tissue factor(sTF) enables us to measure the plasma levels of the activated form of factor VII(FVIIa) without the effect of the FVII zymogen form. We have developed the fluorogenic assay for FVIIa using sTF and measured the plasma FVIIa in atherosclerotic diseases. The FVIIa level in the Japanese was lower than that reported in Caucasians, suggesting that the incidence of ishemic heart disease is lower in the former. The FVIIa level was higher in the patients with cardiovascular diseases (ischemic heart disease and cerebral infarction), non-insulin-dependent diabetic mellitus, hypertension with microalbuminuria, and renal failure than in the healthy controls. The FVIIa levels were also increased in non-insulin-dependent diabetic patients, and this FVIIa increase was positively correlated with urinary albumin excretion. Furthermore, FVIIa levels were not correlated with the levels of lipids and the activity of hepatic synthesis, indicating that FVIIa may be an independent risk factor for cardiovascular disease.
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PMID:[Activated factor VII as a new cardiovascular risk factor of atherothrombotic disease]. 856 29

The Northwick Park Heart Study found that factor VII (FVII) activity was a risk factor for ischemic heart disease, and other studies based on indirect assays of activated factor VII (FVIIa) found an elevation of FVIIa postprandially. We hypothesized that postprandial elevation of FVIIa would produce intermittent activation of factor X to Xa and, subsequently, prothrombin to thrombin. We chose to study postprandial activation of coagulation with a new assay specific for FVIIa that uses soluble tissue factor and with a prothrombin fragment 1 + 2 (F1 + 2) assay to detect the activation of prothrombin by factor Xa. We fed a high-fat breakfast (30 g/m2) to 30 healthy volunteer subjects (30.8 +/- 9.8 years; range, 20 to 49 years) on no medication. Fasting blood samples were collected for FVIIa, FVII antigen (FVIIag). and F1 + 2 as well as triglycerides and total and HDL cholesterol. A significant difference was found between fasting (2.82 +/- 1.49 ng/mL. mean +/- SD) and 6-hour postprandial (3.45 +/- 2.08 ng/mL) FVIIa levels (P < .004); FVIIag did not change significantly (mean, 0.89 U/mL fasting and 0.90 U/mL at 6 hours). In contrast, F1 + 2 levels were slightly lower 6 hours postprandially than fasting (median, 0.39 versus 0.44 nmol/L, P < .02). Four-hour postprandial triglyceride levels correlated significantly (p = 0.51, P < .02) with 6-hour postprandial FVIIag but not with 6-hour postprandial FVIIa. Postprandial F1 + 2 levels (at 6 hours) correlated significantly (p = 0.39, P < .04) with fasting FVIIag levels but not with 6-hour postprandial FVIIa levels. Thus, the basal FVIIag level, in the fasting state, may be involved in control of the generation of F1 + 2. We found a postprandial increase in FVIIa levels after a dietary fat load but did not find a concomitant postprandial burst of activation of factor X and prothrombin as measured by F1 + 2. Further studies are to test whether postprandial FVIIa generation leads to enhanced activation of coagulation.
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PMID:Postprandial elevation of activated factor VII in young adults. 891 Dec 70

Angiotensin converting enzyme inhibitors (ACE-I) have been reported to prevent the recurrence of cardiovascular events. The mechanism of this decrease, however, can not be completely explained by anti-hypertensive and anti-hypertrophic effects of ACE-I. To investigate the mechanism of this decrease, we studied the regulation of plasminogen activator inhibitor-1 (PAI-1), tissue type plasminogen activator (TPA), tissue factor (TF), and tissue factor pathway inhibitor (TFPI) by angiotensin II (Ang II) in cultured rat aortic endothelial cells. Ang II increased PAI-1 and TF mRNA expression without affecting that of TPA or TFPI. These inductions were accompanied by increases in PAI-1 and TF activities and were inhibited by a type I Ang II receptor antagonist. The results suggest that Ang II decreases the antithrombotic properties of endothelial cells which increases the chance of thrombosis. Thus, inhibition of the renin-angiotensin system may be beneficial to prevent thrombus formation in treatment of ischemic heart disease.
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PMID:Angiotensin II increases plasminogen activator inhibitor-1 and tissue factor mRNA expression without changing that of tissue type plasminogen activator or tissue factor pathway inhibitor in cultured rat aortic endothelial cells. 924 56

The initial step in atherosclerosis is the rapid targeting of monocytes to the sites of inflammation and endothelial injury. Serum levels of intercellular adhesion molecule-1 were found to be increased in ischaemic heart disease patients and polymorphisms in the E-selectin gene were associated with accelerated atherosclerosis in young (age < 40 years) patients, further suggesting a role of inflammation in atherosclerosis. Cholesterol loading in macrophages was found to induce interleukin-8 expression, suggesting an association between foam cell formation and beta 2-integrin-dependent adhesion of leukocytes. Enhanced endothelium-platelet interaction induced by hypercholesterolaemia is mediated by von Willebrand factor, whereas platelet adhesion to subendothelial matrix is mediated by fibulin-fibrinogen complexes. Activated platelets mediate the homing of leukocytes by interaction with the subendothelial matrix under shear stresses that do not allow neutrophil adhesion. They may also contribute to the oxidative modification of LDL, provide a source of lipids for foam cell generation and contribute to smooth muscle cell proliferation. Oxidized LDL induces tissue factor in macrophages that also provide sites for fibrin polymerization and decreases the anticoagulant activity of endothelium by interfering with thrombomodulin expression and inactivating tissue factor pathway inhibitor. Intravascular fibrinolysis induced by tissue-type plasminogen activator or urokinase may contribute to the initiation of atherosclerosis by inducing P-selectin and platelet activating factor as well as to plaque rupture, either directly or indirectly, by activating metalloproteinases. Plasminogen activator inhibitor-1 inhibits smooth muscle cell migration and, in the presence of vitronectin, promotes the clearance of thrombin by LDL receptor-related protein at sites of endothelial injury.
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PMID:Thrombosis and atherosclerosis. 933 57

Using a model of chronic ischemic heart disease (recurring coronary insufficiency against the background of chronic hypercholesterolemia), regularities were studied of the microcirculation rearrangements in the myocardium. Employed in the studies were methods of light optics, electron microscopy, injection, as was morphometry. All structural and functional links of the myocardial microcirculation system were put to study, such as resistive, metabolic and blood-drawing segments of the microhemocirculatory channel, intramyocardial tracts of lymph outflow, and interstitium as a direct carrier of the intratissue milieu, as well as subepicardial portion of the lymphatic network of the heart. There have been determined the morphofunctional equivalents and morphogenesis of those changes disorganizing the transport processes in the myocardium under the above type disorder, such as changes in microhaemodynamics, permeability of the histohematic barrier, lymph outflow, and intermediary exchange; there have also been analysed the pathogenetic interrelations thereof. The results obtained suggest that dysfunction of the myocardial system of microcirculation should have a part as a local tissue factor of pathogenesis of cardiac insufficiency in ischemic heart disease.
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PMID:[The transport-trophic support of myocardial function in the modelling of chronic ischemic heart disease]. 947 76

Coronary atherosclerosis is by far the most frequent cause of ischemic heart disease and plaque disruption with superimposed thrombosis is the main cause of the acute coronary syndromes of unstable angina, myocardial infarction, and sudden coronary death. Therefore, for event-free survival, the vital question is not why atherosclerosis develops but rather why, after years of indolent growth, it suddenly becomes complicated by life-threatening thrombosis. Therefore, we have to focus on plaque composition and vulnerability to rupture and plaque thrombogenicity rather than on plaque size and stenosis severity. The risk for plaque disruption depends more on plaque vulnerability (plaque type) than on degree of stenosis (plaque size). Lipid-rich and soft plaques are more vulnerable and prone to rupture than collagen-rich and hard plaques. They are also highly thrombogenic after disruption because of high content of tissue factor. There seems to be three major determinants of a plaque's vulnerability to rupture: 1) the size and consistency of the lipid-rich atheromatous core, 2) the thickness of the fibrous cap covering the core, and 3) ongoing inflammation and repair processes within the fibrous cap. Lipid accumulation, cap thinning, lack of smooth muscle cells (smc), and macrophage-related inflammation destabilize plaques, making them vulnerable to rupture. In contrast, smc-related healing and repair processes stabilize plaques, protecting them against disruption. Plaque size or stenosis severity tell nothing about a plaque's vulnerability. Many vulnerable plaques are invisible angiographically due to their small size and compensatory vascular remodeling.
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PMID:Plaque pathology and coronary thrombosis in the pathogenesis of acute coronary syndromes. 1038 96

Functional inhibition of tissue factor (TF) has been shown to improve coronary blood flow after myocardial ischemia/reperfusion (I/R) injury. TF initiates the coagulation protease cascade, resulting in the generation of the serine protease thrombin and fibrin deposition. Thrombin can also contribute to an inflammatory response by activating various cell types, including vascular endothelial cells. We used a rabbit coronary ligation model to investigate the role of TF in acute myocardial I/R injury. At-risk areas of myocardium showed increased TF expression in the sarcolemma of cardiomyocytes, which was associated with a low level of extravascular fibrin deposition. Functional inhibition of TF activity with an anti-rabbit TF monoclonal antibody administered either 15 minutes before or 30 minutes after coronary ligation reduced infarct size by 61% (P = 0.004) and 44% (P = 0.014), respectively. Similarly, we found that inhibition of thrombin with hirudin reduced infarct size by 59% (P = 0.014). In contrast, defibrinogenating the rabbits with ancrod had no effect on infarct size, suggesting that fibrin deposition does not significantly contribute to infarct size. Functional inhibition of thrombin reduced chemokine expression and inhibition of either TF or thrombin reduced leukocyte infiltration. We propose that cardiomyocyte TF initiates extravascular thrombin generation, which enhances inflammation and injury during myocardial I/R.
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PMID:Inhibition of the tissue factor-thrombin pathway limits infarct size after myocardial ischemia-reperfusion injury by reducing inflammation. 1110 58


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