Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To test the hypothesis that the direct thrombin inhibitor, melagatran is able to inhibit local pro-carboxypeptidase U (proCPU) activation that occurs during thrombolytic treatment, t-PA alone, or in combination with melagatran, was given to dogs with a coronary artery thrombosis. Blood samples from the great cardiac vein and aorta were collected at baseline, during thrombus formation, throughout the t-PA+/-melagatran infusion and during the patency period, for analysis of CPU activity using a novel assay. A higher CPU activity in venous compared to arterial blood (V-A difference) indicates CPU activation in coronary vessels. Efficacy was assessed by determination of time to lysis, duration of patency and blood flow during patency. Dogs (n = 26) were randomized to receive either 1) t-PA, 1 mg/kg as an intravenous 20-min infusion; 2) t-PA as in group 1, +melagatran bolus, 0.3 mg/kg, followed by a 3-h infusion (0.15 mg/kg per h); 3) sham-operated but no coronary thrombus, and administered t-PA as for Group 1. All groups had similar baseline characteristics. Significant increases in CPU activity were observed in Groups 1 and 2 during thrombus formation, with V-A differences of 5.5 and 4.5 U/L, respectively. No significant V-A difference was observed in the sham-operated group. CPU activity increased in Group 1 during the t-PA infusion (V-A difference 15.9 U/L), whereas the V-A difference in Group 2 decreased to 2.6 U/L following melagatran treatment. These results demonstrate that melagatran attenuates generation of CPU in the coronary circulation. The mechanism is probably indirect, via inhibition of thrombin-mediated activation of proCPU.
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PMID:Local proCPU (TAFI) activation during thrombolytic treatment in a dog model of coronary artery thrombosis can be inhibited with a direct, small molecule thrombin inhibitor (melagatran). 1200 34

Patients with coronary heart disease (CHD) are at considerable risk for recurrent ischaemic events. A pre-thrombotic state and/or impaired fibrinolysis might play an important role in causing recurrent ischaemic events. Two hundred and fifty-seven CHD patients underwent the dobutamine stress echocardiography test (DSE) to investigate the possible presence of inducible ischaemia; 89 patients showed evidence of stunned and/or necrotic myocardium (resting wall motion abnormalities). Factor VIII activity and fibrinogen levels were significantly higher in patients with stunned/necrotic myocardium than in CHD patients with normal resting wall motions (factor VIII activity, P = 0.004; fibrinogen, P = 0.04). Of interest, after stimulating the fibrinolytic system with the DSE test, plasminogen activator inhibitor-1 activity was significantly higher in patients with necrotic/stunned myocardium than in patients with resting normal wall motion (P = 0.03), whereas tissue-type plasminogen activator activity after the DSE test was significantly lower in patients with stunned/necrotic myocardium than in patients with normal wall motion (P = 0.001). Overall, 30 CHD patients developed induced ischaemia (new wall motion abnormalities) during the DSE test. CHD patients with stunned and/or necrotic myocardium presented decreased fibrinolytic potential and the presence of a hypercoagulable state due to increased factor VIII activity, and fibrinogen levels. Therefore, these CHD patients must be considered at high risk of re-developing coronary thrombosis and might benefit from a more aggressive anticoagulant therapy.
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PMID:Pre-thrombotic state and impaired fibrinolytic potential in coronary heart disease patients with left ventricular dysfunction. 1254 31

Thrombus formation after rupture of an atherosclerotic plaque plays a crucial role in coronary artery disease (CAD). A decreased endogenous fibrinolytic system and prothrombotic factors are supposed to influence coronary thrombosis. It was our aim to investigate the predictive value of tissue plasminogen activator (t-PA) antigen, von Willebrand Factor, Lipoprotein (a) and anti-cardiolipin antibodies for major adverse coronary events in patients with stable CAD in a prospective cohort study of more than 10 years. We observed 141 patients with angiographically proven CAD for a median follow-up period of 13 years. t-PA antigen was the only marker predicting coronary events (logistic regression, p = 0.044) with a poor prognosis for patients in the 5th quintile with an odds ratio of 7.3 (compared to the 1st quintile). The odds ratio even increased to 10.0 for coronary events associated with the "natural course" of CAD excluding events due to restenosis. t-PA antigen had a slightly higher prognostic power (ROC curve; AUC = 0.69) than fasting glucose (AUC = 0.68) and cholesterol (AUC = 0.67). Triglycerides influenced plasma levels of t-PA antigen (regression, p < 0.001). The predictive value of t-PA antigen remained significant after adjustment for inflammation (logistic regression, p = 0.013) and extent of CAD (p = 0.045) but disappeared adjusting for insulin resistance (p = 0.12). In conclusion t-PA antigen predicted coronary events during a very long-term follow-up with a comparable prognostic power to established cardiovascular risk factors. Markers of insulin resistance influenced t-PA antigen and its predictive value.
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PMID:Circulating t-PA antigen predicts major adverse coronary events in patients with stable coronary artery disease--a 13-year follow-up. 1288 83

When dealing with acute coronary syndromes, the interventionists often go straight to balloon and stents, because they work quick and well in the majority of cases. However, it is not to forget that vigorous antithrombotic treatment is frequently highly beneficial in these settings. We report here on two clinical cases of coronary thrombosis in which we could appreciate on the angiograms the effect of GP IIb/IIIa inhibitor eptifibatide alone or in conjunction with alteplase.
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PMID:Angiographic demonstration of coronary dethrombosis with eptifibatide. 1515 11

In the present study, a polymer-encapsulated plasminogen activator was investigated as an alternative to restore blood flow more effectively than free plasminogen activator. While current fibrinolytic agents have limited efficacy, attributable to delayed onset of sustained reperfusion and bleeding complications, encapsulated plasminogen activators have shown promise in addressing these shortcomings. A polymer-encapsulated plasminogen activator could offer an effective formulation with a prolonged shelf-life. In this study, coronary artery thrombosis was produced in the anesthetized dog by the injection of thrombin + whole blood, and then one of five randomly selected formulations was administered intravenously: saline, blank microcapsules, free streptokinase (FREE SK), streptokinase and blank microcapsules (FREE SK + BLANK), or streptokinase entrapped in polymer microcapsules (MESK). MESK significantly accelerated the time to reperfusion compared to FREE SK or FREE SK + BLANK. Additionally, substantial reductions were observed in residual clot mass, infarct mass, reocclusion episodes, fibrinogen depletion and blood loss with MESK compared to FREE SK. The results of this study demonstrate that MESK accelerates thrombolysis and the restoration of blood flow compared to identical dosages of FREE SK while also reducing systemic fibrinogenolysis and blood loss. Microencapsulation may produce an improved dosage form for restoring arterial blood flow and reducing bleeding complications with thrombolytic therapy.
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PMID:Encapsulation of a plasminogen activator speeds reperfusion, lessens infarct and reduces blood loss in a canine model of coronary artery thrombosis. 1517 9

The objective of this study was to test the hypothesis if thrombolysis induced by recombinant tissue-type plasminogen activator, (rt-PA) could be facilitated by inhibiting carboxypeptidase U (CPU, active Thrombin Activatable Fibrinolysis Inhibitor, TAFIa) activity. The efficacy of rt-PA alone, or in combination with the carboxypeptidase inhibitor MERGETPA, was compared in a dog model of coronary artery thrombosis. Twenty dogs were randomised in two groups, one received rt-PA, 1 mg kg(-1), as intravenous infusion over 20 min starting 30 min after thrombus formation, and the other group received rt-PA, 1 mg kg(-1), as group one with the addition of MERGEPTA 5 mg kg(-1) starting 25 min prior to coronary artery occlusion and followed by infusion of 5 mg kg(-1) h(-1) until the end of experiment. Efficacy was assessed by determination of time to lysis, duration of patency and blood flow during patency. Both groups had similar baseline characteristics with respect to haemodynamic parameters, i.e., heart rate, blood pressure and coronary artery blood flow. Coadministration of rt-PA and MERGETPA resulted in significant decrease in time to lysis (15+/-1.5 min vs. 20+/-1.7 min, p=0.03), increased patency time (87+/-16 min vs. 46+/-12 min, p=0.047) and increased coronary blood flow during patency (1131 mL h(-1) vs. 405 mL h(-1), p=0.015), compared to rt-PA alone. These results indicate that an inhibitor of CPU activity may have a beneficial effect in patients undergoing thrombolytic therapy by attaining shorter time to reperfusion and improved coronary patency.
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PMID:Inhibition of carboxypeptidase U (TAFIa) activity improves rt-PA induced thrombolysis in a dog model of coronary artery thrombosis. 1618 87

The treatment of acute ischemic stroke (AIS) using thrombolysis with recombinant tissue-plasminogen activator (rtPA, alteplase) is limited by its narrow time window and the risk of hemorrhage. Recombinant plasminogen activator (rPA, reteplase) has been used clinically on coronary artery thrombosis and acute myocardial infarction. It is necessary to induce strokes experimentally as a means of validating the rPA timing on patients with AIS. However, current embolic models cannot mimic clinical situations well due to the embolus's composition of dried blood clots or artificial materials. In this paper, we used two novel rat thromboembolic models to determine the dosage-effect relationship and therapeutic time window of r-PA. Male rats were administered rPA or rtPA intravenously at 2-12h postischemia. Cerebral blood flow, behavioral outcomes and infarct volume within the same animal group were determined. Our results demonstrated that rPA (0.2 and 0.4mg/kg) or rtPA (0.2mg/kg) restored focal perfusion, reduced cerebral infarction, and improved behavioral outcomes at 2-4h postischemia. rPA but not rtPA significantly restored focal perfusion at 6h postischemia. However, delayed rPA-treatment neither decreased infarct volume nor improved the neurological disorder. Cerebral hemorrhage occurred at 6h postischemia detected by Evan's blue leakage and tissue hemoglobin content. Collectively, Thrombolysis with rPA may be beneficial in revascularization at an acceptable dosage of 0.2-0.4mg/kg within 6h after the cerebral infarct onset.
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PMID:Effect of recombinant plasminogen activator timing on thrombolysis in a novel rat embolic stroke model. 2703 32

Recombinant plasminogen activator (reteplase) is a third generation thrombolytic agent which has been used on coronary artery thrombosis and acute myocardial infarction. Clot lysis assay is usually considered as a unique method to evaluate biological activity of reteplase. In this study biological activity of reteplase was determined by APTT (activated partial thromboplastin time) lysis method. Validity of this method was evaluated in comparison with reference method, clot lysis time assay. Results of APTT lysis test showed good reproducibility (relative standard deviation (RSD) 3-5% for within day analysis and 4-7% for between day analysis), and accuracy (101.3-102.7%). APTT lysis responses were linear in range of 0.001-0.1 mg/mL reteplase. Therefore, APTT lysis method is applicable for biological activity determination of reteplase. Although more comprehensive studies are required to approve this test as a reference method, APTT lysis method seems to be valuable to receive more attention due to advantages of technical simplicity, sensitivity, applicability, and cost efficiency.
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PMID:Determination of Biological Activity of Recombinant Reteplase Using Clot Lysis Time and Activated Partial Thromboplastin Time (APTT) Lysis Methods: A Comparative Study. 3056 7


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