Thromb Haemost 2002; 87(04): 557-562
DOI: 10.1055/s-0037-1613049
In Focus
Schattauer GmbH

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)

C. Mattsson
1   AstraZeneca, Mölndal, Sweden
,
J. A. Björkman
1   AstraZeneca, Mölndal, Sweden
,
T. Abrahamsson
1   AstraZeneca, Mölndal, Sweden
,
V. Nerme
1   AstraZeneca, Mölndal, Sweden
,
K. Schatteman
2   Laboratory of Medical Biochemistry, University of Antwerp, Belgium
,
J. Leurs
2   Laboratory of Medical Biochemistry, University of Antwerp, Belgium
,
S. Scharpé
2   Laboratory of Medical Biochemistry, University of Antwerp, Belgium
,
D. Hendriks
2   Laboratory of Medical Biochemistry, University of Antwerp, Belgium
› Institutsangaben
Weitere Informationen

Publikationsverlauf

Received 10. Juli 2001

Accepted after revision 07. Februar 2002

Publikationsdatum:
08. Dezember 2017 (online)

Summary

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.

 
  • References

  • 1 Hendriks D, Scharpé S, van Sande M, Lommaert MP. Characterization of a carboxypeptidase in human serum distinct from carboxypeptidase N. J Clin Chem Clin Biochem 1989; 27: 277-85.
  • 2 Hendriks D, Wang W, Scharpé S, Lommaert MP, van Sande M. Purification and characterization of a new arginine carboxypeptidase in human serum. Biochem Biophys Acta 1990; 1034: 86-92.
  • 3 Bajzar L, Morser J, Nesheim M. TAFI, or plasma pro-carboxypeptidase B couples the coagulation and fibrinolytic cascades through the thrombinthrombomodulin complex. J Biol Chem 1996; 271: 16603-8.
  • 4 Eaton DL, Malloy BE, Tsai SP, Henzel W, Drayna D. Isolation, molecular cloning, and partial characterisation of a novel carboxypeptidase B from human plasma. J Biol Chem 1991; 266: 21833-8.
  • 5 Bajzar L, Nesheim ME, Tracy PB. The profibrinolytic effect of activated protein C in clots formed from plasma is TAFI-dependent. Blood 1996; 88: 2093-100.
  • 6 Nerme V, Åkerblom B, Legnehed A, Scharpé S, Hendriks D. Carboxypeptidase U inhibitors increase the rate of fibrinolysis in a rat DIC model. Fibrinolysis & Proteolysis 2000; 14 Suppl: (01) 69.
  • 7 Redlitz A, Nicolini FA, Malycky JL, Topol EJ, Plow EF. Inducible carboxypeptidase activity. A role in clot lysis in vivo. Circulation 1996; 93: 1328-30.
  • 8 Refino CJ, Schmitt D, Pater C, Eaton D, Bunting S. A carboxypeptidase inhibitor markedly improves the potency of t-PA in vivo [abstract]. Fibrinolysis & Proteolysis 1998; 12 Suppl: (01) 29.
  • 9 Klement P, Liao P, Bajzar L. A novel approach to arterial thrombolysis. Blood 1999; 94: 2735-43.
  • 10 Uriuda Y, Wang Q-D, Grip L. et al. Antithrombotic activity of inogatran, a new low molecular weight thrombin inhibitor, in a closed-chest porcine model of coronary artery thrombosis. Cardiovasc Res 1996; 32: 320-7.
  • 11 Chen L, Nichols W, Mattsson C. et al. Inogatran, a novel direct low molecular weight thrombin inhibitor, given with, but not after, tissueplasminogen activator improves thrombolysis. J Pharmacol Exp Ther 1996; 277: 1276-83.
  • 12 Mattsson C, Björkman J-A, Ulvinge J-C. Melagatran, hirudin and heparin as adjuncts to tissue-type plasminogen activator in a canine model of coronary artery thrombolysis. Fibrinolysis & Proteolysis 1997; 11: 121-8.
  • 13 Gustafsson D, Antonsson T, Bylund R. et al. Effects of melagatran, a new low molecular weight thrombin inhibitor, on thrombin and fibrinolytic enzymes. Thromb Haemost 1998; 79: 110-8.
  • 14 Blair E, Nygren E, Cowley RA. A spiral wire technique for producing gradually occlusive coronary thrombosis. J Thorac Cardiovasc 1964; 48: 476-85.
  • 15 Cercek B, Lew AS, Hod H. et al. Enhancement of thrombolysis with tissuetype plasminogen activator by pretreatment with heparin. Am Heart J 1986; 74: 583-7.
  • 16 Bergmann SR, Fox KAA, Ter-Pogossian MM, Sobel BE, Collen D. Clot-selective coronary thrombolysis with tissue-type plasminogen activator. Science 1983; 220: 1181-3.
  • 17 Schatteman KA, Goossens FJ, Scharpé SL, Neels HM, Hendriks DF. Measurement of procarboxypeptidase U in human plasma. Clin Chem 1999; 45: 807-13.
  • 18 Hendriks D, Scharpé S, van Sande M. Assay of carboxypeptidase N activity in serum by liquid- chromatographic determination of hippuric acid. Clin Chem 1985; 12: 1936-9.
  • 19 Rowland M, Tozer TN. Assessment of AUC. In: Balabo D. ed. Clinical Pharmacokinetics, Concepts and Applications. 3rd edition. Williams & Wilkins; 1995: 469-72.
  • 20 Schatteman KA, Goossens FJ, Scharpé SS, Hendriks DF. Activation of plasma procarboxypeptidase U in different mammalian species points to a conserved pathway of inhibition of fibrinolysis. Thromb Haemost 1999; 82: 1718-21.
  • 21 Jackson CV, Wilson HC, Growe VG, Shuman RT, Gesellchen PD. Reversible tripeptide thrombin inhibitors as adjunctive agents to coronary thrombolysis: A comparison with heparin in a canine model of coronary artery thrombosis. J Cardiovasc Pharm 1993; 21: 587-94.
  • 22 Reganon E, Ferrando F, Vila V. et al. Increase in thrombin generation after coronary thrombolysis with rt-PA or streptokinase with simultaneous heparin versus heparin alone. Haemostasis 1998; 28: 99-105.
  • 23 Refino CJ, DeGuzman L, Schmitt D. et al. Consequences of inhibition of plasma carboxypeptidase B on in vivo thrombolysis, thrombosis and hemostasis. Fibrinolysis & Proteolysis 2000; 14: 305-14.
  • 24 Nagashima M, Werner M, Wang M. et al. An inhibitor of activated thrombinactivatable fibrinolysis inhibitor potentiates tissue-type plasminogen activator-induced thrombolysis in a rabbit jugular vein thrombolysis model. Thromb Res 2000; 98: 333-42.
  • 25 Minnema MC, Friederich PW, Levi M. et al. Enhancement of rabbit jugular vein thrombolysis by neutralisation of factor XI. In vivo evidence for a role of factor XI as an anti-fibrinolytic factor. J Clin Invest 1998; 101: 10-4.
  • 26 Nerme V, Åkerblom B, Abrahamsson T. The combined inhibition of carboxypeptidase U and thrombin increases synergistically the rate of fibrinolysis in a rat DIC model. [Abstract] Blood vol. 96 November 2000
  • 27 Weitz JI, Hudoba D, Massel J, Maraganore J, Hirsh J. Clot-bound thrombin is protected from inhibition by heparin-antithrombin but is susceptible to inactivation by antithrombin-independent inhibitors. J Clin Invest 1990; 86: 385-91.