Platelet hyperactivity in thalassemia patients with elevated tricuspid regurgitant velocity and the association with hemolysis.

Abstract

INTRODUCTION:

Pulmonary arterial hypertension is a life-threatening complication in thalassemia characterized by elevated pulmonary arterial pressure. Increased platelet activation is associated with this complication; however, its role remains unclear.

METHODS:

Platelet activation in splenectomized β-thalassemia/hemoglobin E (Hb E) patients was measured using flow cytometric determination of P-selectin and activated glycoprotein (aGP) IIb/IIIa expression, and platelet-leukocyte aggregates (platelet-neutrophil, platelet-monocyte and platelet-lymphocyte aggregates). Tricuspid regurgitant velocity (TRV) was measured and used as an indicator of pulmonary arterial pressure. Plasma hemoglobin served as markers of hemolysis.

RESULTS:

Fifteen of 27 patients had elevated TRV (>2.5m/s). Platelet expression of P-selectin and aGPIIb/IIIa, and platelet-leukocyte aggregates were higher in thalassemia patients with elevated TRV than healthy control. Platelet-neutrophil aggregates increased in thalassemia patients with elevated TRV compared to patients with normal TRV. The increase in P-selectin and aGPIIb/IIIa expression induced by adenosine diphosphate (ADP) was higher in patients with elevated TRV than those with normal TRV. Platelet P-selectin expression and platelet-neutrophil aggregates correlated positively with TRV. Plasma hemoglobin levels in patients with elevated TRV were higher than those of the control subjects, and correlated with TRV.

CONCLUSION:

Thalassemia patients with elevated TRV have a further increase in platelet activation that correlates with hemolysis.

• Authors: Sirada Srihirun, Navy Tanjararak, Suporn Chuncharunee, Piyamitr Sritara, Rassamon Kaewvichit, Suthat Fucharoen, Kovit Pattanapanyasat, Nathawut Sibmooh
• Journal: Thrombosis research (Thromb Res) Vol. 135 Issue 1 Pg. 121-6 (Jan 2015) ISSN: 1879-2472 [Electronic] United States
• PMID: 25455999 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2014 Elsevier Ltd. All rights reserved.

Chemical References

• Hemoglobins
• P-Selectin

Topics

• Adult
• Blood Platelets (cytology)
• Blood Pressure
• Blood Transfusion
• Case-Control Studies
• Flow Cytometry
• Hemoglobins (metabolism)
• Hemolysis
• Humans
• Leukocytes (cytology)
• Middle Aged
• Neutrophils (cytology)
• P-Selectin (blood)
• Platelet Activation
• Pulmonary Artery (pathology)
• Tricuspid Valve (pathology)
• Tricuspid Valve Insufficiency
• beta-Thalassemia (blood)