Hamdan Medical Journal (previously the Journal of Medical Sciences)

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Modulation of Serine Proteases-Mediated Platelet Activation

Sarfraz Ahmad
Published in : Journal of Medical Sciences ; Vol 3, No 1 (2010)
DOI : 10.2174/1996327001003010044

Abstract


Novel direct thrombin inhibitors (DTIs), such as bivalirudin, are replacing heparin in several clinical scenarios. In particular, DTIs are indicated for the treatment and thromboprophylaxis of patients with heparin-induced thrombocytopenia (HIT). In interventional cardiology, DTIs have several advantages over heparin, and offer a clinical benefit equivalent to that of a combination of heparin and antiplatelet agents. We hypothesize that this benefit results from the ability of DTIs to inhibit platelet activation by activated serine proteases. This study represents the development of a modified 14C-serotonin release assay (SRA) to investigate the relative inhibitory effects of three DTIs (argatroban, bivalirudin and hirudin) on thrombin- and factor Xa-mediated 14C-serotonin release (SR) in plasma-free systems. Washed platelets were isolated from blood of healthy volunteers. The 14CSRA test was similar to that used to detect heparin-PF4 antibody-mediated platelet activation, except that it was used to evaluate the ability of DTIs to modulate protease-induced SR responses. The inhibitory effects of DTIs were determined at protease concentrations that induced ≥50% SR. Serine proteases induced SR from platelets in a concentration-dependent manner. Human thrombin was found to be more potent than bovine thrombin (2-3 times for 50-80% SR). Bovine factor Xa (≥0.2 nKat/ml) produced a comparable (50- 80%) SR response. All three DTIs effectively blocked serine protease-mediated platelet activation in a concentrationdependent manner. The optimum inhibitory concentrations of bivalirudin on SR was ~100 nM for human thrombin and bovine factor Xa and almost double for bovine thrombin; well below plasma concentrations necessary for effective anticoagulation for percutaneous coronary interventions. Wide variations in the inhibitory effects of each DTI on thrombin- and factor Xa-mediated platelet activation were noted, which was partly dependent on the donor platelets and stability of the proteases/inhibitors. It is concluded that DTIs can directly inhibit serine proteases- mediated platelet activation responses.

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References


Kahn ML, Nakanishi-Mitsui M, Shapiro MJ, Ishihara H,Coughlin SR. Protease-activated receptors 1 and 4 mediate activation of human platelets by thrombin.J Clin Invest 1999; 103: 879-87.

Andersen H, Greenberg DL, Fujikawa K, Xu W,Chung DW, Davie ED. Protease-activated receptor 1 is the primary mediator of thrombin-stimulated platelet procoagulant activity. Proc Natl Acad Sci USA 1999; 96: 11189-93.

Ramakrishnan V, De Guzman F, Bao M, Hall SW,Leung LL, Phillips DR. A thrombin receptor function for platelet glycoprotein Ib-IX unmasked by cleavage of glycoprotein V. Proc Natl Acad Sci USA 2001; 98: 1823-8.

Fabris F, Ahmad S, Cella G, Jeske WP, Walenga JM,Fareed J. Pathophysiology of heparin-induced thrombocytopenia: Clinical and diagnostic implications- A review. Arch Pathol Lab Med 2000; 124:1657-66.

Ahmad S. Heparin-induced thrombocytopenia:Impact of bovine versus porcine heparin in HIT pathogenesis. Front Biosci 2007; 12: 3312-20.

Hirsh J. Heparin. N Engl J Med 1991; 324: 1565-74.

Weitz JI, Crowther M. Direct thrombin inhibitors.Thromb Res 2002; 106: V275-V284.

Bates SM, Weitz JI. Direct thrombin inhibitors for treatment of arterial thrombosis: Potential differences between bivalirudin and hirudin. Am J Cardiol 1998; 82: 12P-18P.

Iqbal O, Ahmad S, Lewis BE, Walenga JM, Rangel Y, Fareed J. Monitoring of argatroban in ARG310 Study: Potential recommendations for its use in interventional cardiology. Clin Appl Thromb Hemost 2002; 8: 217-24.

Ng NJ, Crowther M. New anticoagulants and the management of their bleeding complications.Transfus Altern Transfus Med 2006; 8(Suppl.1): 12-9.

Hursting MJ, Jang IK. Effect of body mass index on argatroban therapy during percutaneous coronary intervention. J Thromb Thrombolysis 2008; 25: 273-9.

Bates SM, Weitz JI. The status of new anticoagulants.Br J Haematol 2006; 134: 3-19.

Murphy GS, Marymont JH. Alternative anticoagulation management strategies for the patient with heparin-induced thrombocytopenia undergoing cardiac surgery. J Cardiothorac Vasc Anesth 2007;21: 113-26.

Dager WE, Dougherty JA, Nguyen PH, Militello MA, Smythe MA. Heparin-induced thrombocytopenia:Treatment options and special considerations.Pharmacotherapy 2007; 27: 564-87.

Stubbs MT, Bode W. A player of many parts: The spotlight falls on thrombin’s structure. Thromb Res 1993; 69: 1-58.

Ahmad S, Walenga JM, Jeske WP, Cella G, Fareed J. Functional heterogeneity of anti-heparin-platelet factor 4 antibodies: Implications in the pathogenesis of the HIT syndrome. Clin Appl Thromb Hemost 1999; 5(Suppl. 1): S32-S37.

Sheridan D, Carter C, Kelton, JG. A diagnostic test for heparin-induced thrombocytopenia. Blood 1986; 67: 27-30.

Berry CN, Girardot C, Lecoffre C, Lunven C. Effects of the synthetic thrombin inhibitor argatroban on fibrin- or clot-incorporated thrombin: Comparison with heparin and recombinant hirudin. Thromb Haemost 1994; 72: 381-6.

Califf RM. A perspective on the regulation of the evaluation of new antithrombotic drugs. Am J Cardiol 1998; 82: 25P-35P.

Banner DW, Hadvary P. Crystallographic analysis at 3.0 Ao resolution of the binding of human thrombin of four active-ite irected inhibitors. J Biol Chem 1991; 266: 20085-91.

Bode W, Turk D, Sturzebecher L. Geometry of binding of the benzamadine- and arginine-based inhibitors N-alpha-(2-naphthyl-sulphonyl-glycyl)-DL-pamidinophenylalanyl-piperidine (NAPAP) and(2R,4R)-4-methyl-1-[N alpha-(3-methyl-1,2,3,4-tetrahydro-8-qyinoline-sulfonyl)-L-arginyl]-2- piperidinecarboxylic acid (MQPA) to human alpha/thrombin: X-ray crystallographic determination of the NAPAP-trypsin complex and modeling of NAPAP-thrombin and MQPA-thrombin. Eur J Biochem 1990; 193: 175-81.

Chesebro JH, Zoldhelyi P, Badimon L, Fuster V. Role of trombin in aterial trombosis: Implications for therapy. Thromb Haemost 1991; 66: 1-5.

Walenga JM, Ahmad S, Hoppensteadt D, Iqbal O, Hursting MJ, Lewis BE. Argatroban therapy does not generate antibodies that alter its anticoagulant activity in patients with heparin-induced thrombocytopenia.Thromb Res 2002; 105: 401-5.

Ginsberg JS, Nurmohamed MT, Gent M, MacKinnon B, Sicurella J, Brill-Edwards P, et al. Use of hirulog in the prevention of venous thrombosis after mjor hip or knee surgery. Circulation 1994; 90: 2385-9.

Chew DP. Bivalirudin, a bivalent, thrombin specificanticoagulant as an alternative to heparin in interventional procedures. Hamostaseologie 2002; 22:60-6.

Fox I, Daeson A, Loynds P, Eisner J, Findlen K, Levin E, et al. Anticoagulant activity of hirulog, a direct thrombin inhibitor, in humans. Thromb Haemost 1993; 69: 157-63.

Bittl JA, Chaitman FR, Feit F, Kimball W, Topol EJ. Bivalirudin versus heparin during coronary angioplasty for unstable or postinfarction angina: Final report reanalysis of the Bivalirudin Angioplasty Study. Am Heart J 2001; 142: 952-9.

Seybert, AL. Bivalirudin administration during percutaneous coronary intervention: Emphasis on highrisk patients. Pharmacotherapy 2002; 22: 112S-118S.

Vanholder R, Camez A, Veys N, Van Loo A, Dhondt AM, Ringoir S. Pharmacokinetics of recombinant hirudin in hemodialyzed end-stage renal failure patients.Thromb Haemost 1997; 77: 650-5.

Serruys PW, Herrman JP, Simon R, Rutsch C, Bode W, Laarman GJ, et al. A Comparison of hirudin with heparin in the prevention of restenosis after coronary angioplasty - Helvetica Investigators. N Engl J Med 1995; 333: 757-63.

Grienacher A, Volpel J, Janssens U, Hach-Wunderle V, Kemles-Matthes B, Eichler P, et al. Recombinant hirudin (lepirudin) provides safe and effective anticoagulation in patients with heparin-induced thrombocytopenia: A prospective study. Circulation 1999; 99: 73-80.

Song X, Huhle G, Wang L, Hoffmann U, Harenberg J. Generation of anti-hirudin antibodies in heparininduced thrombocytopenic patients treated with rhirudin. Circulation 1999; 100: 1528-32.

Eichler P, Friesen H-J, Lubelow N, Jaeger B, Greinacher A. Antihirudin antibodies in patients with heparin-induced thrombocytopenia treated with lepirudin: Incidence, effects on aPTT, and clinical relevance. Blood 2000; 96: 2373-8.

The GUSTO IIb Investigators. A comparison of recombinant hirudin with heparin for the treatment of acute coronary syndromes. The Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO) IIb Investigators. N Engl J Med 1996; 335:775-82.

Anonymous. Comparison of the effects of two doses of recombinant hirudin compared with heparin in patients with acute myocardial ischemia without ST elevation: A pilot study. Organization to Asses Strategies for Ischemis Syndromes (OASIS) Investigators. Circulation 1997; 96: 769-77.

Anonymous. Effects of recombinant hirudin (lepirudin)compared with heparin on death, myocardial infarction, refractory angina, and revascularisation procedures in patients with acute myocardial ischaemia without ST elevation: A randomized trial. Organization to Assess Strategies for Ischemis Syndromes (OASIS-2) Investigators. Lancet 1999;353 (9151): 429-38





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