Evaluation of platelet function in essential thrombocythemia under different analytical conditions

Area of Science:

• Hematology
• Thrombosis Research

Background:

• Essential thrombocythemia (ET) is characterized by elevated platelet counts.
• Previous studies on platelet aggregation (PA) in ET have yielded conflicting results, potentially due to variations in experimental conditions.

Purpose of the Study:

• To investigate the impact of different analytical techniques and conditions on platelet aggregation in ET patients.
• To clarify discrepancies in previous findings regarding PA in ET.

Main Methods:

• Platelet aggregation was assessed using light-transmission aggregometry (LTA) and impedance aggregometry.
• Tests were performed on platelet-rich plasma (PRP) and whole blood (WB) using various agonists (ADP, collagen, TRAP-14, adrenaline).
• Blood samples were collected in citrate (low Ca2+) or lepirudin (physiological Ca2+), with adjusted or native platelet counts.

Main Results:

• Platelet aggregation in ET patients varied depending on the method and conditions used.
• Under less physiological conditions (e.g., adjusted citrate-PRP with LTA), PA was lower in ET compared to controls.
• Under more physiological conditions (e.g., lepirudin-treated samples), PA tended to be normal or higher in ET patients.
• Reduced platelet serotonin and ADP content, increased P-selectin expression, and higher platelet-leukocyte aggregates were observed in ET patients.

Conclusions:

• The analytical conditions employed significantly influence the in vitro assessment of platelet aggregation in ET.
• Platelet aggregation in ET appears defective under non-physiological conditions but normal or even enhanced under physiological conditions.
• These findings underscore the importance of standardized, physiologically relevant methods for evaluating platelet function in ET.