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Effects of activated complements on platelets
1Department of Pharmacology, Zhongshan Medical College, Sun Yat-Sen University, Guangzhou 510089, China.
Acta Pharmacologica Sinica
|July 11, 2003
Summary
Complement activation alters platelets, leading to vascular endothelial cell (VEC) injury and accelerated vascular smooth muscle cell (VSMC) growth. This process may influence blood coagulation and chronic inflammation.
Area of Science:
- Immunology
- Cell Biology
- Vascular Biology
Background:
- Complement activation plays a role in inflammatory and thrombotic processes.
- Platelets are key mediators in hemostasis and inflammation.
- Vascular endothelial cells (VEC) and vascular smooth muscle cells (VSMC) are crucial for vascular homeostasis.
Purpose of the Study:
- To investigate the impact of complement activation on platelets.
- To determine the subsequent effects of activated platelets on VEC and VSMC.
Main Methods:
- Platelet activation by Zymosan A was assessed using aggregometry and prothrombinase activity assays.
- Supernatants from activated platelets were applied to cultured VEC and VSMC to evaluate cell growth, DNA content, and membrane microviscosity.
Main Results:
- Zymosan A induced platelet shape change, increased microviscosity, and prothrombinase expression.
- Activated platelet supernatant inhibited VEC growth but promoted VSMC proliferation, driving them into G2/M phase.
- Ultrastructural changes were observed in both VEC and VSMC.
Conclusions:
- Complement-activated platelets release factors that injure VEC and stimulate VSMC growth.
- These findings suggest a role for complement-mediated platelet activation in blood coagulation and chronic inflammation.