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A Eldor, I Vlodavsky, U Martinowicz, Z Fuks and BS Coller
Cultured endothelial cells produce an extracellular matrix (ECM) to which
platelets adhere and spread, ultimately resulting in platelet aggregation,
thromboxane B2 production, and serotonin release. We have investigated the
role of fibrinogen binding to the platelet GPIIb/IIIa complex in these
reactions by comparing normal platelet-rich plasma (PRP), PRP from patients
with Glanzman's thrombasthenia (whose platelets lack the GPIIb/IIIa
complex), PRP in the presence of a monoclonal antibody that blocks the
binding of fibrinogen to the GPIIb/IIIa complex, platelets washed free of
fibrinogen, and washed platelets to which fibrinogen was added. Although
platelet aggregation was virtually completely inhibited in the samples in
which the normal interaction between fibrinogen and GPIIb/IIIa was
impaired, adhesion of platelets to the matrix, spreading, and release of
[14C]-serotonin were not affected. All of the platelet preparations
released significant amounts of T X B2 with time, but there was a decrease
in the amount produced by both the thrombasthenic and antibody-treated
platelets. We conclude that the interaction of fibrinogen with platelet
GPIIb/IIIa is not required for platelet adhesion to ECM or for
adhesion-induced shape change or serotonin release. On the other hand, the
platelet-fibrinogen interaction may play some role in augmenting
adhesion-induced T X B2 production, and it is absolutely required for
adhesion-induced platelet aggregation.
This article has been cited by other articles:
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| Copyright © 1985 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||
