Internalization of cell-derived microparticles triggers endothelial pro-inflammatory responses

Area of Science:

• Hematology
• Vascular Biology
• Cellular Biology

Background:

• Circulating microparticles (MPs) are elevated in thalassemia and linked to endothelial dysfunction and thromboembolic events.
• Mechanisms of MP-endothelial cell interactions and their consequences are not fully understood.

Purpose of the Study:

• To compare the effects of MPs from healthy individuals and beta-thalassemia/HbE patients on endothelial pro-inflammatory responses.
• To investigate the role of splenectomy in modulating MP-induced endothelial activation.

Main Methods:

• MPs were isolated from plasma of healthy donors and splenectomized/non-splenectomized beta-thalassemia/HbE patients.
• Isolated MPs were characterized, quantified, and incubated with human umbilical vein endothelial cells (HUVECs).
• MP internalization, endothelial cell activation, and pro-inflammatory gene/protein expression were assessed.

Main Results:

• MPs from all groups were internalized by HUVECs.
• MPs from splenectomized beta-thalassemia/HbE patients induced a significant 2-fold upregulation of IL1B, CXCL8, and CCL2, and a 4-fold increase in interleukin-1β.
• Higher MP concentrations (5 × 10⁶/ml) induced IL-6 and IL-8 secretion, while lower concentrations did not.

Conclusions:

• Plasma MPs from splenectomized beta-thalassemia/HbE patients activate endothelial cells, inducing pro-inflammatory responses at both gene and protein levels.
• These findings suggest a specific role for MPs from splenectomized patients in driving endothelial inflammation.