Factor VII-Deficient Substrate Plasmas Depleted of Protein C Raise the Sensitivity of the Factor VII Bio-Assay to Activated Factor VII: an International Study

Summary

Plasma from healthy individuals, pregnant women and patients on warfarin were distributed to 3 laboratories supporting major cardiovascular surveys (Northwick Park, Muenster and Houston) for assay of factor VII coagulant activity (VII_C) with their own bio-assays. The mean VII_C in 147 samples agreed to within 1% of standard in Northwick Park and Houston, but was 14% of standard lower in Muenster owing to its more potent standard. In samples with an increased VII_C the Northwick Park assay gave a higher result than the other assays owing to its increased responsiveness to activated factor VII (VII_a). Thus when VII_a concentrations were determined directly with a clotting assay which utilises a soluble recombinant tissue factor, the increase in VII_C with increase in VII_a was considerably greater with the Northwick Park assay than the Muenster assay. This feature of the Northwick Park assay was traced to the virtual absence of protein C in its substrate plasma. Factor V_a appears rate-limiting for the coagulant expression of VII_a in test plasma. If the thrombotic response to release of tissue factor is determined by the circulating concentration of VII_a, then the Northwick Park factor VII bio-assay may be preferable to other bio-assays currently employed to estimate risk of acute coronary events.

• References

• 1 Meade TW, Mellows S, Brozovic M, Miller GJ, Chakrabarti RR, North WR S, Haines AP, Stirling Y, Imeson ID, Thompson SG. Haemostatic function and ischaemic heart disease: principal results of the Northwick Park Heart Study. Lancet 1986; 2: 533-7
• 2 Balleisen L, Assmann G, Epping PH, Schulte H, van de Loo J. Coagulation factors and the progress of coronary heart disease. Lancet 1987; 2: 461
• 3 Atherosclerosis Risk in Communities Study Manual 9: Hemostasis determinations. Published by the National Heart Lung and Blood Institute of the National Institute of Health, Collaborative Studies Coordinating Center. University of North Carolina; Chapel Hill, NC, USA: April 1987
• 4 Papp AC, Hatzakis H, Bracey A, Wu KK. ARIC Hemostasis Study – 1. Development of blood collection and processing system suitable for multicenter hemostatic studies. Thromb Haemost 1989; 61: 15-9
• 5 Heinrich J, Balleisen L, Schulte H, Assmann G, van de Loo J. Fibrinogen and factor VII in the prediction of coronary risk. Results from the PROCAM Study in healthy men. In press
• 6 Brozovic M, Stirling Y, Harricks C, North WR S, Meade TW. Factor VII in an industrial population. Br J Haematol 1974; 28: 381-91
• 7 Quick AJ. The prothrombin in haemophilia and in obstructive jaundice. J Biol Chem 1935; 109: 73-4
• 8 Denson KW E. The specific assay of Prower-Stuart factor and factor VII. Acta Haematol 1961; 25: 105-20
• 9 Lechner K, Deutsch E. Eine einfache Methode zur Herstellung von menschlichem Faktor-VII-Mangelplasma. Thromb Diath Haemorrh 1967; 18: 252-8
• 10 Morrissey JH, Macik BG, Neuenschwander PF, Comp PC. Quantitation of activated factor VII levels in plasma using a tissue factor mutant selectively deficient in promoting factor VII activation. Blood 1993; 81: 734-44
• 11 Kitchin S, Malia RG. An assay for extrinsic pathway inhibition. Med Lab Sci 1989; 46 Suppl (Suppl. 01) 40
• 12 Stenflo J. A new vitamin K-dependent protein. J Biol Chem 1976; 251: 355-63
• 13 Kisiel W. Human plasma protein C: isolation, characterization, and mechanism of activation by alpha-thrombin. J Clin Invest 1979; 64: 761-9
• 14 Freyssinet JM, Wiesel ML, Grunebaum L, Pereillo JM, Gauchy J, Schuhler S, Freund G, Cazenave JR. Activation of human protein C by blood coagulation factor X_a in the presence of anionic phospholipids. Biochem J 1989; 261: 341-8
• 15 Vehar GA, Davie EW. Preparation and properties of bovine factor VIII (antihemophilic factor). Biochemistry 1980; 19: 410-6
• 16 Kisiel W, Canfield WM, Ericsson H, Davie EW. Anticoagulant properties of bovine plasma protein C following activation by thrombin. Biochemistry 1977; 16: 5824-31
• 17 Nesheim ME, Taswell JB, Mann KG. The contribution of bovine factor V and factor V_a to the activity of prothrombinase. J Biol Chem 1979; 254: 10952-62
• 18 Bauer KA, Kass BL, Beeler DL, Rosenberg RD. Detection of protein C activation in humans. J Clin Invest 1984; 74: 2033-41
• 19 Suzuki K, Nishioka J, Hashimoto S. Protein C inhibitor. Purification from human plasma and characterization. J Biol Chem 1983; 258: 163-8
• 20 Espana F, Vicente V, Tabernero D, Scharrer I, Griffin JH. Determination of plasma protein C inhibitor and of two activated protein C-inhibitor complexes in normals and in patients with intravascular coagulation and thrombotic disease. Thromb Res 1990; 59: 593-608
• 21 Gruber A, Griffin JH. Direct detection of activated protein C in blood from human subjects. Blood 1992; 79: 2340-8
• 22 Esmon CT, Owen WG. Identification of an endothelial cell co-factor for thrombin-catalysed activation of protein C. Proc Natl Acad Sci USA 1981; 78: 2249-52
• 23 Ishii H, Nakano M, Ishubouchi J, Kazama M, Majerus PW. Distribution of thrombomodulin in human tissues and characterization of thrombomodulin in plasma. Acta Haematol Jpn 1988; 51: 1228-33
• 24 Dittman WA, Majerus PW. Structure and function of thrombomodulin: a natural anticoagulant. Blood 1990; 75: 329-36
• 25 Salem HH, Broze GJ, Miletich JP, Majerus PW. Human coagulation factor V_a is a co-factor for the activation of protein C. Proc Natl Acad Sci USA 1983; 80: 1584-8
• 26 Davies M. A macroscopic and microscopic view of coronary thrombi. Circulation 1990; 82: 1138-46
• 27 Miller GJ, Wilkes HC, Meade TW, Bauer KA, Barzegar S, Rosenberg RD. Haemostatic changes that constitute the hypercoagulable state. Lancet 1991; 338: 1079