Abstract
The activity of the fibrinolytic system is regulated by activators and inhibitors. The inactive zymogen plasminogen, upon activation by the tissue-type plasminogen activator (t-PA) or by the urinary-type plasminogen activator (u-PA or urokinase) is converted to plasmin, a protease which degrades fibrin into soluble fibrin degradation products (Fig. 1). t-PA is synthesized by endothelial cells and is continuously released into the blood stream; its release can be considerably enhanced by many agents, acidosis and hypoxia [1]. In human blood, t-PA exists in two forms: in a free, single-chain form (sct-PA) and in an inactive form bound to the plasminogen activator inhibitor type 1 (PAI-1). Small amounts of plasmin convert sct-PA to twochain t-PA (tct-PA). The other PA, u-PA, exists in human blood as a true inactive zymogen in single-chain form (scu-PA or pro-urokinase). It can be converted to the active two-chain form (tcu-PA; urokinase) by trace amounts of plasmin or of kallikrein. Beside PAI-1 which inhibits both forms of t-PA and urokinase (but not prourokinase) another inhibitor, a2-antiplasmin, rapidly inactivates free plasmin.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Bachmann F (1987) Fibrinolysis. In: Verstraete M, Vermylen J, Lijnen R, Arnout J (eds) Thrombosis and Haemostasis. Leuven University Press, pp 227–265
Bachmann F, McKenna R, Cole ER, Najafi H (1975) The hemostatic mechanism after openheart surgery. I. Studies on plasma coagulation factors and fibrinolysis in 512 patients after extracorporeal circulation. J Thorac Cardiovasc Surg 70: 76–85
Berridge DC, Burgess-Wilson ME, Westby JC, Hopkinson BR, Makin GS (1989) Differential effects of low-dose tissue plasminogen activator and streptokinase on platelet aggregation. Br J Surg 76: 1026–1030
Bidstrup BP, Royston D, Sapsford RN, Taylor KM (1989) Reduction in blood loss and blood use after cardiopulmonary bypass with high dose aprotinin (Trasylol). J Thorac Cardiovasc Surg 97: 364–372
Bleyl H, Roka L (1988) Serpincomplexes as indicators of thrombophilic states. Haemostasis 18 (Suppl S2): 54
Coller BS (1990) Platelets and thrombolytic therapy. N Engl J Med 322: 33–42
Edmunds LH (1989) Blood platelets and bypass [invited letter]. J Thorac Cardiovasc Surg 97: 470–471
Ghebrehiwet B, Randazzo BP, Dunn JT, Silverberg M, Kaplan AP (1983) Mechanism of activation of the classical pathway of complement by Hageman factor fragment. J Clin Invest 71: 1450–1457
Hauert J, Nicoloso G, Schleuning WD, Bachmann F, Schapira M(1989) Plasminogen activators in Dextran sulfate-activated euglobulin fractions: A molecular analysis of factor XII- and prekallikrein-dependent fibrinolysis. Blood 73: 994–999
Holloway DS, Summaria L, Sandesara J, Vagher JP, Alexander JC, Caprini JA (1988) Decreased platelet number and function and increased fibrinolysis contribute to postoperative bleeding in cardiopulmonary bypass patients. Thromb Haemost 59: 62–67
Kucuk O, Kwaan HC, Frederickson J, Wade L, Green D (1986) Increased fibrinolytic activity in patients undergoing cardiopulmonary bypass operation. Am J Hematol 23: 223–229
Lottenberg R, Sjak-Shie N, Fazleabas AT, Roberts RM (1988) Aprotinin inhibits urokinase but not tissue-type plasminogen activator. Thromb Res 49: 549–556
McKenna R, Bachmann F, Whittaker B, Gilson JR, Weinberg M (1975) The hemostatic mechanism after open-heart surgery. II. Frequency of abnormal platelet functions during and after extracorporeal circulation. J Thorac Cardiovas Surg 70: 298–308
Miles LA, Ginsberg MH, White JG, Plow EF (1986) Plasminogen interacts with human platelets with two distinct mechanisms. J Clin Invest 77: 2001–2009
Park S, Harker LA, Marzec UM, Levin EG (1989) Demonstration of single chain urokinasetype plasminogen activator on human platelet membrane. Blood 73: 1421–1426
Royston D, Bidstrup BP, Taylor KM, Sapsford RN (1987) Effect of aprotinin on need for blood transfusion after repeat open-heart surgery. Lancet ii: 1289–1291
Stibbe J, Kluft C, Brommer EJP, Gomes M, De Jong DS, Nauta J (1984) Enhanced fibrinolytic activity during cardiopulmonary bypass in open-heart surgery in man is caused by extrinsic (tissue-type) plasminogen activator. Eur J Clin Invest 14: 375–382
Van Oeveren W, Harder MP, Roozendaal KJ, Eijsman L, Wildevuur CRH (1990) Aprotinin protects platelets against the initial effect of cardiopulmonary bypass. J Thorac Cardiovas Surg 99: 788–797
Van Oeveren W, Jansen NJG, Bidstrup BP, Royston D, Westaby S, Neuhof H, Wildevuur CRH (1987) Effects of aprotinin on hemostatic mechanisms during cardiopulmonary bypass. Ann Thorac Surg 44: 640–645
Vaughan DE, Mendelsohn ME, Declerck PJ, Van Houtte E, Collen D, Loscalzo J (1989) Characterization of the binding of human tissue-type plasminogen activator to platelets. J Biol Chem 264: 15869–15874
Verstraete M (1985) Clinical application of inhibitors of fibrinolysis. Drugs 29: 236–261
Wachtfogel YT, Harpel PC, Edmunds LH, Colman RW (1989) Formation of C 1s–C 1-inhibitor, kallikrein-C 1-inhibitor, and plasmin-a2-plasmin-inhibitor complexes during cardiopulmonary bypass. Blood 73: 468–471
Wachtfogel YT, Kucich U, Greenplate J, Gluszko P, Abrams W, Weinbaum G, Wenger RK, Rucinski B, Niewiarowski S, Edmunds LH, Colman RW (1987) Human neutrophil degranulation during extracorporeal circulation. Blood 69: 324–330
Wenger RK, Lukasiewicz H, Mikuta BS, Niewiarowski S, Edmunds LH (1989) Loss of platelet fibrinogen receptors during clinical cardiopulmonary bypass. J Thorac Cardiovasc Surg 97: 235–239
Zilla P, Fasol R, Groscurth P, Klepetko W, Reichenspurner H, Wolner E (1989) Blood platelets in cardiopulmonary bypass operations. Recovery occurs after initial stimulation, rather than continual activation. J Thorac Cardiovasc Surg 97: 379–388
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1991 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Bachmann, F., Bachmann, F. (1991). Fibrinolysis. In: Friedel, N., Hetzer, R., Royston, D. (eds) Blood Use in Cardiac Surgery. Steinkopff, Heidelberg. https://doi.org/10.1007/978-3-662-06119-0_1
Download citation
DOI: https://doi.org/10.1007/978-3-662-06119-0_1
Publisher Name: Steinkopff, Heidelberg
Print ISBN: 978-3-662-06121-3
Online ISBN: 978-3-662-06119-0
eBook Packages: Springer Book Archive