Increasing platelet aggregability after venepuncture is platelet, not plasma derived.

Area of Science:

• Hematology
• Platelet Physiology

Background:

• Platelet aggregation is crucial for hemostasis.
• Understanding factors affecting platelet responsiveness is important for transfusion medicine and thrombosis research.

Purpose of the Study:

• To investigate the time course of adenosine diphosphate (ADP)-induced platelet aggregation in stored human platelet-rich plasma.
• To determine if platelet storage itself influences aggregation rates.

Main Methods:

• Human platelet-rich plasma was collected and aliquots were tested for ADP-induced aggregation at 3.5, 10, 30, and 100 minutes post-venepuncture.
• Constant pH, CO2, and temperature were maintained throughout the experiment.
• Platelet aggregation was also assessed using fresh plasma with prestored platelets, and after acetylsalicylic acid inhibition of cyclooxygenase.

Main Results:

• The maximal rate of ADP-induced platelet aggregation significantly increased over the 100-minute storage period.
• This acceleration in aggregability was observed despite constant sample pH, CO2, and temperature.
• The effect was attributed to platelet storage, not changes in plasma factors, and was not affected by cyclooxygenase inhibition.

Conclusions:

• Human platelet aggregability to ADP increases during storage in platelet-rich plasma.
• Platelet storage itself, rather than plasma composition changes, drives this enhanced responsiveness.
• These findings have implications for understanding platelet function over time in stored blood products.