Platelets Collagen

Tandon N. N Kralisz U, Jamieson G. A. Identification of glycoprotein IV (CD36) as a primary receptor for platelet collagen adhesion. J Biol Chem 1989 264,7576-83. 

Platelet-collagen interactions are believed to have the greatest significance at the medium and high shear rates found in arteries and diseased vessels. The binding between immobilized vWF and GPIb/IX/V is reversible and slows the... 

Nieswandt B,Watson S. Platelet-collagen interaction is GPVI the central receptor Blood 2003 102 449-461. 

Platelet/collagen adhesion can be classified into two categories primary adhesion and secondary re orcing adhesion. Primary adhesion can be categorised into divalent cation-independent and Mg -dependent adhesion. 

Over the years a large number of molecules have been proposed as direct platelet/collagen receptors but recently these have been narrowed down to a few ... 

Thus it is unlikely that CD36 plays a majm role in platelet/collagen interactirms. 

Brass LF, Bensusan HB The role of quaternary structure in platelet-collagen interaction. J Clin Invest 54 1480-1487,1974... 

Kehrel B Platelet-collagen interactions. Semin Thromb Hemost 21 123-129,1995... 

Gralnick HR, McKeown LP, Williams SS, Lawrence JC, Shafer BC, Kramer WS, Hanemann KE, Vail MU, Magruder LE A murine numoclonal antibody that identifies a 157/130kI>a platelet collagen receptor. Circulation 78 308,1988 (abstract)... 

Several newer approaches to antiplatelet drug development have been recently discovered (122). These include inhibitions of the vWf/GPIb interaction, the platelet/collagen interaction, and the thrombin-induced platelet activation. Other approaches to platelet inhibition include the use of serotonin antagonists (because serotonin induces platelet aggregation), nitric oxide-donating antiplatelet agents, phosphodiesterase inhibitors, and inducers of adenyl cyclase. 

Clemetson KJ, Clemetson JM (2001) Platelet collagen receptors. Thromb Haemost... 

Product name (Generic, Trade Names, Manufacturer/ Distributor) Fibrin Sealant, Hemaseel APR, Haemacure, Tisseel VH, Baxter Healthcare Platelet Gel, Medtronic Harvest Technologies, and others Collagen Enhanced Fibrin Sealant, CoStasis, Cohesion Technologies, US Surgical Collagen -F Thrombin, FloSeal, Fusion Medical, Proceed Sulzer Medica... 

Components/ mechanism of action Human plasma, fibrinogen and thrombin, virally inactivated, hemostat, sealant. Autologous fibrinogen -t-platelet-rich plasma, hemostatic gel. Bovine collagen, bovine thrombin, plus autologous human plasma, hemostatic agent. Bovine collagen and bovine thrombin. Expands 20% which aids in hemostatic effect. 

Fibrin sealant, thrombin and collagen, fibrin sealant plus collagen, and platelet gels... 

Itazigrel (137) is an antithrombotic compound because of its inhibition of platelet aggregation induced by collagen. It is synthe.sizcd froin l-bromo-l-(4-methoxy)benzoyl-4-methoxytol-uene (135) by reaction in the usual way with triflucffothioacetamide (136) to give itazigrel 471. 

Collagen is a major component of connective tissue that becomes exposed at the subendothelium of injured blood vessels. It contributes to platelet adhesion and also plays a role in platelet activation by binding to several receptors on platelets such as integrin a 2(3 1 or glycoprotein VI (GP VI). 

Platelets adherent to collagen change shape and spread out on the subendothelium. They release the contents of their storage granules (the dense granules and the alpha granules) secretion is also stimulated by thrombin. 

Integrins themselves are found on nearly all cells and mediate several physiological responses, such as cell-cell and cell-matrix interactions. Three families of integrins, each family with a common beta subunit in combination with distinct alpha subunits, have been recognized. The beta 1 family, also called very late lymphocyte-activation antigen or VLA, has receptors mediating extracellular matrix interactions with molecules such as collagen, laminin, and fibronectin. Naturally, platelets contain many of the receptors of the beta 1 family. 

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