Molecular insights into the anticoagulant-induced spontaneous activation of platelets in whole blood-various anticoagulants are not equal.
The spontaneous anticoagulant-dependent platelet activation in vitro may potentially interfere with the determination of haemostatic parameters. The effects of various blood anticoagulants on platelet activation were monitored using flow cytometry. Regardless of a blood anticoagulant used (EDTAK2, heparin, citrate or PPACK), platelet activation began immediately after blood withdrawal and was most pronounced in the EDTAK2-anticoagulated blood samples. The progressing expression of GMP-140 antigen was accompanied by the enhanced abundance of the subunit beta 3 of the platelet membrane integrin alpha IIb beta 3 without parallel changes in the fluorescence attributed to the complex form of the integrin alpha IIb beta 3. The increased expression of GMP-140 was paralleled by the enhanced platelet clumping in the samples anticoagulated with either EDTAK2 or heparin, and the raised platelet microparticles in blood withdrawn into citrate. The EDTAK2-induced platelet activation was markedly reduced by methyl 2,5-dihydroxycinnamate, tyrosine kinase inhibitor. The influence of disodium EDTA on platelet membrane dynamics closely mimicked the alterations induced upon the interaction of fibrinogen with platelet GPIIb-IIIa. Thus, the EDTAK2-induced platelet activation might result from an interference with platelet membrane protein structure and conformation and possibly related to an "unspecific" trigerring of a signal transduction pathway. Overall, EDTAK2 and heparin appeared the least suitable anticoagulants, particularly with the regard to the expression of GMP-140 antigen. The failure to recognize the importance of a spontaneous anticoagulant-induced platelet activation may result in misdiagnoses during the monitoring of coagulation parameters.
Golański
J
J
Laboratory of Haemostatic Disorders, Medical University of Lódź, Poland.
Pietrucha
T
T
Baj
Z
Z
Greger
J
J
Watala
C
C
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology*; D000925:Anticoagulants / Q000494:pharmacology*; D005434:Flow Cytometry; D006493:Heparin / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D019007:P-Selectin / Q000032:analysis*; D015539:Platelet Activation / Q000187:drug effects*
D000590:Amino Acid Chloromethyl Ketones; D000925:Anticoagulants; D019007:P-Selectin; D006493:Heparin; C040308:phenylalanyl-prolyl-arginine-chloromethyl ketone