We have studied the interaction of ASvWf with human platelets in PRP and in suspensions of washed platelets containing either physiological or low external ionized calcium concentration [Ca2+](o). In hirudin-PRP or in washed platelets in 1.5-2 mM CaCl2, ASvWf up to 50 μg/ml does not induce platelet aggregation or the release reaction. When [Ca2+](o) is decreased by addition of citrate to hirudin-PRP or when no CaCl2 is added to washed platelet suspensions, ASvWf does induce platelet aggregation and the release reaction. In low [Ca2+](o), ASvWf interacts with platelet GPIb to cause primary aggregation of disc-shaped platelets to each other through GPIIb/IIIa, with or without added fibrinogen. This primary platelet aggregation leads to thromboxane A2 formation and secondary aggregation and the release reaction. With [Ca2+](o) in the physiological range, there is less ASvWf interaction with GPIb, no primary platelet aggregation and no thromboxane A2 formation. The ASvWf-platelet interaction at physiological [Ca2+](o), however, enhances the platelet response to collagen or epinephrine.
|Number of pages||9|
|Journal||Thrombosis and Haemostasis|
|Publication status||Published - 1988|
ASJC Scopus subject areas