Role of platelet factor Xa in chylomicron-prothrombin complexes induced platelet activation.
The effects of chylomicron-prothrombin complexes on platelet activation, including platelet aggregation, serotonin release, arachidonic acid release and increases of platelet cytosolic [Ca2+]i were examined. Furthermore the role of platelet factor Xa on the conversion of chylomicron bound prothrombin to thrombin was studied by using a synthetic inhibitor of factor Xa, TenStop. The chylomicron-prothrombin complexes could induce platelet aggregation and enhance the platelet serotonin release and arachidonic acid release in contrast to native chyle chylomicrons. An increase of platelet [Ca2+]i was observed during incubation with chylomicron-prothrombin complexes. TenStop inhibited platelet aggregation and serotonin release that were induced by chylomicron-prothrombin complexes in a dose-dependent manner, whereas the TenStop itself did not inhibit the platelet aggregation induced by thrombin and collagen. It is concluded that platelet activation induced by chylomicron-prothrombin complexes is related to the platelet factor Xa that could be the key factor in the conversion of chylomicron bound prothrombin to thrombin.
Xu
N
N
Department of Medicine, University Hospital of Lund, Sweden.
Zhou
L
L
Ohlin
A K
AK
Nilsson
A
A
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002914:Chylomicrons / Q000494:pharmacology*; D015951:Factor Xa / Q000502:physiology*; D065427:Factor Xa Inhibitors; D006801:Humans; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D015539:Platelet Activation / Q000187:drug effects*; D010974:Platelet Aggregation / Q000187:drug effects; D011516:Prothrombin / Q000494:pharmacology*; D051381:Rats; D012701:Serotonin / Q000378:metabolism
D002914:Chylomicrons; D065427:Factor Xa Inhibitors; D046911:Macromolecular Substances; D016718:Arachidonic Acid; D012701:Serotonin; D011516:Prothrombin; D015951:Factor Xa; D002118:Calcium