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Platelet heterogeneity: variation in coagulation complexes on platelet subpopulations
Christine L Kempton1, Maureane Hoffman, Harold R Roberts
1University of North Carolina, Chapel Hill, NC 27599-7035, USA.
Arteriosclerosis, Thrombosis, and Vascular Biology
|January 18, 2005
Summary
Platelets stimulated with convulxin and thrombin show increased binding of coagulation factors V, VIII, IX, and X on a subpopulation. This phenomenon enhances thrombin generation, indicating a broader role beyond alpha-granule components.
Area of Science:
- Hematology
- Biochemistry
- Cell Biology
Background:
- Platelets exhibit heterogeneous responses to agonists like thrombin and convulxin.
- Previous studies identified two platelet populations with differing alpha-granule factor V binding after stimulation.
Purpose of the Study:
- To determine if increased coagulation factor binding is limited to alpha-granule components.
- To investigate the binding of factors V, VIII, IX, and X on convulxin- and thrombin-stimulated platelets.
Main Methods:
- Flow cytometry was used to quantify coagulation factor binding on platelet surfaces.
- Simultaneous measurement of factor Xa and thrombin generation was performed.
- Correlation between coagulation factor binding and thrombin generation was analyzed.
Main Results:
- Stimulation with convulxin and thrombin increased the surface binding of factors V, VIII, IX, and X on a platelet subpopulation.
- This subpopulation development was dependent on convulxin concentration.
- Increased factor binding correlated with enhanced factor Xa and thrombin generation.
Conclusions:
- Enhanced coagulation factor binding to platelets is not restricted to alpha-granule proteins.
- The proportion of platelets with increased factor binding regulates convulxin-induced thrombin generation.