Activated platelet-derived microparticles in thalassaemia

Area of Science:

• Hematology
• Thrombosis Research
• Cell Biology

Background:

• Thalassaemia patients exhibit increased thromboembolic complications.
• Abnormal red blood cell aggregability and elevated microparticles (MPs) are implicated in thrombotic risk.

Purpose of the Study:

• To investigate the quantity, cellular origin, and procoagulant properties of MPs in beta-thalassaemia.
• To understand the role of MPs in the thrombotic risk associated with beta-thalassaemia.

Main Methods:

• Flow cytometry was used to analyze MPs in fresh whole blood from beta-thalassaemia/HbE patients (splenectomised and non-splenectomised) and normal individuals.
• Blood samples were stained for annexin V, cellular antigens (CD41a, CD62P, CD36), and density beads.
• Platelet factor-3-like activity was measured to assess procoagulant properties of phosphatidylserine (PS)-bearing MPs.

Main Results:

• Splenectomised beta-thalassaemia/HbE patients showed significantly higher levels of PS-bearing MPs compared to non-splenectomised patients and controls (P < 0.0001).
• A strong correlation was found between PS-bearing MPs and PS-bearing platelets, indicating chronic platelet activation (r(s) = 0.511, P < 0.001).
• PS-bearing MPs primarily originated from activated platelets, and platelet procoagulant activity was elevated in splenectomised patients, correlating with MP levels.

Conclusions:

• Microparticles in beta-thalassaemia, particularly from activated platelets, contribute to thrombotic risk.
• Elevated levels of these procoagulant MPs, especially in splenectomised patients, can aggravate thrombotic events.