| Research Abstract |
The aim of this study is to evaluate the importance of platelet-microparticles (MPs), a carrier of platelet-activating factor (PAF), in the pathogenesis of remote organ failure in ischemia-reperfusion injury in vascular surgery.
We found that PAF is concentrated and associated with MPs released from high shear stress-induced activated platelets. PAF was released from activated platelets 3 minutes after stimulation. Eighty percent of the PAF released from the platelets was recovered in the MPs fraction, and PAF was 30-fold concentrated in MPs upon stimulation (lwamoto, Kawasaki, BBRC 239, 101-105, 1997). And PAF and 12-HETE but not TXA2 were encapsulated in MPs released from activated platelets.
We investigated the possible existence of MPs in serum LDL fractions. After 10 minutes stimulation of platelet rich plasma with thrombin+collagen, LDL and IDL fractions were obtained. PAF and MPs were identified in LDL and IDL fractions but not in HDL and VLDL fractions. And PAF in MPs is relatively stable and protected from the hydrolysis by acetylhydrolase under physiological condition.
The release of microparticles was identified in severe SIRS, surgical operation and reperfusioninjury after limb salvage. And the patelets were highly potentiated by such insult.
ASA resistance may be caused by an increased sensitivity of platelets to collagen. Platelet aggregation study specific for collagen dose response may be useful for strict selection of ASA responders for lowdose ASA therapy and for identifying ASA non-responders for high-dose ASA therapy (Stroke 31, 591-595, 2000).
These findings are quite important to resolve complications after the insult and to identify the proper medications.
|
