Platelet BTG release in vitro induced by mechanical and chemical stimulus: correlation with the aggregation curve parameters.

The in vitro release of B-thromboglobulin (BTG) from platelets after stirring the platelet rich plasma (PRP) 5 min (37°C/1000rpm) was studied in a group of 13 healthy subjects before and after ‘in vivo’ aspirin ingestion, 1 g/d for 3 d. A significant reduction in the platelet BTG release (31%) was observed after aspirin ingestion in comparison to the pre-aspirin values, suggesting that the BTG release by stirring is related to a platelet activation process. Small doses of collagen (0.625 μg/ml) and thrombin (0.1 U/ml) always released platelet BTG, whether or not there was a visible platelet aggregation, suggesting that platelet activation is not necessarily followed by visible platelet aggregation. A significant correlation was found between the BTG released by stimulation with collagen (2.5 μg/ml) and thrombin (0.2 U/ml) and the maximum velocity and intensity of the aggregation curve parameters.