Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.7 (plasmin)
 9,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A short history of the research work of S. Okamoto and co-workers, for the previous 50 years, is briefly described. In the 1950s, when the physiologic role of fibrinolysis had not been established, they began to seek for compounds that inhibit the action of plasmin. They examined approximately 200 lysine derivatives and discovered epsilon aminocaproic acid (EACA) and tranexamic acid (t-AMCHA). In the 1970s, we selected thrombin as the target enzyme to be controlled; structure-activity relationship studies, taking arginine as the skeleton structure, led to the discovery of the selective thrombin inhibitor No. 205 (4-ethyl-1-[N2-(5-dimethylamino-1-naphthalenesulfonyl)-L-arginyl]- 1-piperidine), and further attempts to minimize the toxicity finally led to No. 805 (argatroban, MD-805, (2R,4R)-4-methyl-1-(N2-[(3-methyl-1,2,3,4-tetrahydro-8-quinolinyl)-sulfo nyl]-L-arginyl)-2-piperidine carboxylic acid). Argatroban, without any cofactor, inhibits thrombin competitively. The high selectivity of the action of argatroban is promising for treating thrombosis in clinical practice. More recently, taking advantage of our knowledge obtained through previous studies, active center-directed plasmin inhibitors and a selective inhibitor of kallikrein have been found.
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PMID:Enzyme-controlling medicines: introduction. 946 21

Thirty-six mongrel dogs underwent 24hr left ventricular assist. The VAD was placed between the left atrium and the descending aorta, and the dogs were divided into four groups according to type of anticoagulation: no anticoagulation, argatroban, nafamostat mesylate, and nafamostat mesylate + prostacyclin analog. Results of this animal experiment revealed that a newly developed synthetic thrombin inhibitor argatroban can prevent activation of the intrinsic coagulation pathway. Argatroban is efficient under any blood coagulative condition, even lack of anti-thrombin III, because of its direct inhibitory effect on thrombin, making argatroban more useful than heparin as an anticoagulant for LVAD. Argatroban, as well as heparin, provides marked and significant prolongation of the prothrombin time from early assisted circulation, but produces a bleeding tendency. Nafamostat mesylate can maintain blood coagulation parameters within the acceptable range. Combined administration of nafamostat mesylate and a prostacyclin analog cause the least decrease in fibrinogen and alpha2-plasmin inhibitor among the four groups and causes no significant prolongation of prothrombin time.
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PMID:Anticoagulation during use of a left ventricular assist device. 1082 51

We have previously confirmed, using a rat mesenteric arteriole thrombolysis model, that thrombin inhibition induces endogenous thrombolysis in vivo. In addition, we have shown that thrombin-activatable fibrinolysis inhibitor (TAFI) plays a role in the down regulation of endogenous thrombolysis. However, the mechanism of endogenous thrombolysis or spontaneous plasmin generation in vivo remains unclear. It has been shown in an in vitro system that plasma kallikrein activates pro-urokinase (pro uPA) and/or plasminogen, resulting in plasmin generation. These findings suggest that spontaneous fibrinolysis might be mediated by tPA and plasma kallikrein-dependent uPA. The aim of the present study was to examine whether these mechanisms play a dominant role in endogenous thrombolysis in vivo, using our rat mesenteric arterial thrombolysis model. Argatroban infusion enhanced endogenous thrombolysis. PKSI-527, anti uPA and anti tPA IgGs suppressed argatroban-induced thrombolysis. Also, the antibody IgG preparations suppressed endogenous thrombolysis in the absence of argatroban. In the presence of PKSI-527, anti tPA IgG was more effective than anti uPA IgG in suppressing argatroban-induced thrombolysis. The results suggested that both tPA and plasma kallikrein-mediated uPA activation and tPA release contribute to endogenous fibrinolytic or thrombolytic mechanisms.
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PMID:Suppression of argatroban-induced endogenous thrombolysis by PKSI-527, and antibodies to TPA and UPA, evaluated in a rat arterial thrombolysis model. 1271 78

The developments and trends of hemostatic and antithrombotic drugs in Japan were investigated chronologically for the last 50 years after the 2nd World War. 1. Hemostatic drugs are classified into three groups ; capillary stabilizers, blood coagulants and antifibrinolytics. l) As to capillary stabilizers, flavonoid (rutin, 1949), adrenochrome derivative (carbazochrome, 1954) and conjugated estrogen (Premarin, 1964) were introduced therapeutically. Especially, the soluble types of adrenochrome compounds (Adona 1956, S-Adchnon, 1962) were devised and used widely in Japan. 2) Drugs concerning blood coagulation, thrombin, introduced in 1953, and hemocoagulase, a snake venom introduced in 1966, were used clinically. V.K. groups producing various coagulation factors were introduced as V.K1 (Phytonadione, 1962) and V.K2 (rnenatetrenone,1972), and they were admitted in "The Japanese Pharmacopoeia"editions 8 and 14, respectively). 3) Regarding antifibrinolytic drugs, Japanese researchers have made remarkable contributions. e-Aminocapronic acid (Ipsilon, 1962) and tranexamic acid (Transamin, 1965) were developed and used for various abnormal bleedings or hemorrhage associated with plasmin over-activation. tranexamic acid also proved to suppress inflammations of the throat such as tonsillitis, pharyngitis or laryngitis. 2. Antithrombotic drugs are also divided into three groups; anticoagulants, antiplatelet drugs and fibrinolytics.1) The anticoagulants used therapeutically by injection are heparins (Na-salt, 1951; Ca-salt, 1962) and low-molecular-weight heparins such as dalteparin (1992), parnaparin (1994) and reviparin (1999). The low molecule compounds are superior to the original heparins in reducing the risk of bleeding. As oral anticoagulants, coumarin derivatives, dicumarol (1950), ethylbiscoumacetate (1954), phenylindandione (1956) and warfarin (1962) are known. Warfarin potassium is the main drug for oral therapy of thromboembolism lately. Gabexate mesilate (1989) and nafamostat mesilate (1989) were developed in Japan and used for DIC and acute pancreatitis to inhibit protease enzymes. Argatroban is a unique antithrombin product developed by Japanese researchers in 1990, and is used for vascular or cerebral thrombosis. After noticing in 1968 that aspirin inhibits platelet aggregation and prevents myocardial infraction, projects for developing antiplatelet drugs were initiated worldwide. Ticlopidine, originally developed in France, was introduced in 1981 and prevailed widely in Japan for reducing the risk of thrombotic stroke. Aspirin itself was recognized by the FDA (USA) as an antithrombotic drug in 1988, and was also approved by Japanese authorities in 2000. PGE1 clathrate compounds have also been developed as antiplatelet drugs; alprostadil alfadex for injection (1979), and limaprost alfadex for oral use (1988). The PGI2 product, beraprost sodium, for oral use followed them in 1992. Other antiplatelet drugs with unique mechanisms explored in Japan: Ozagrel (1988), which inhibits TXA2 synthetase, cilostazol (1988), which inhibits cAMP phosphodiesterase, and sarpogrelate (1993), which blocks 5HT in platelets, are the notable drugs in this field. Ethyl icosapentate, from fish oil, is available for antiplatelet therapy. Concerning the fibrinolytic system, plasminogen activators are useful for thromboembolism. The streptokinase from bacterial origin developed in the USA and Europe was not introduced, and urokinase (1965) was the first plasminogen activator developed in Japan. Then tissue plasminogen activators (t-PA) tisokinase (cell culture, 1991), alteplase (genetical recombination, 1991), nateplase (genetical recombination, 1996), monteplase (1998) and pamiteplase (1998) were developed and approved for acute myocardial infarction. Nasaruplase (prourokinase, cell culture,1991) was also approved for the same indication. While the development of the hemostatic drugs ceased in the 1960s, avid project studies for antithrombotic drugs including fibrinolytics began in the 1980s and are progressing now towards new molecular targets. This may be due to the increasing tendency of cardiovascular thromboembolic diathesis in Japan. (The figures in parentheses are the years approved by the Japanese Ministry of Health, Labor and Welfare.)
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PMID:[A 50-year history of new drugs in Japan-the development and trends of hemostatics and antithrombotic drugs]. 1457 69

The purpose of this study was to clarify the precise effect of argatroban on the inhibition of cytokine secretion induced by thrombin on synovial cells. The efficiency of thrombin inactivation by thrombin inhibitors was evaluated in human synovial fluids (SFs). In SFs from 13 osteoarthritis (OA) and 11 rheumatoid arthritis (RA) patients, thrombin, Factor Xa (FXa), plasmin activity, IL-6, MMP-3, VEGF, and D-dimer concentrations were measured. Tissue factor (TF) activity or IL-6, MMP-3, and VEGF secretion of human synovial cells with or without thrombin and argatroban were measured. The efficiency of thrombin inactivation in SFs was compared for thrombin inhibitors: argatroban, antithrombin III (ATIII), or heparin cofactor II (HCII). In SFs, thrombin, FXa, plasmin, D-dimer, IL-6, and MMP-3 were significantly higher in RA than in OA. In synovial cell experiments, TNF-alpha and thrombin enhanced TF activity on the cell surface, and IL-6, MMP-3, and VEGF secretion were enhanced by thrombin. Increased TF activity, and IL-6, MMP-3, and VEGF secretion induced by thrombin were inhibited by argatroban. In SFs, argatroban inactivated thrombin more effectively than ATIII or HCII. Since thrombin plays an important role in the disease activity of OA and RA, it is a potential therapeutic molecular target. Argatroban was the most effective anticoagulant to inhibit thrombin activity in SF. Intra-articular injection is ideal administration because it can deliver high dose of argatroban without high risk of systematic complication.
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PMID:Argatroban more effectively inhibits the thrombin activity in synovial fluid than naturally occurring thrombin inhibitors. 2726 98