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Endotoxin induced platelet microvesicle formation measured by flow cytometry
A Larsson1, T Lundahl, M Eriksson
1Department of Clinical Chemistry Mats Eriksson, Kai Lundkvist Department of Anesthesiology and Pediatric Surgery, University Hospital, Uppsala, Linkoping, Sweden.
Platelets
|November 4, 2010
Summary
Endotoxin, a component of gram-negative bacteria, significantly increases platelet microvesicles. These microvesicles are linked to increased coagulation and may play a role in sepsis complications like disseminated intravascular coagulation (DIC).
Area of Science:
- Hematology
- Microbiology
- Immunology
Background:
- Endotoxin (lipopolysaccharide, LPS), a gram-negative bacterial outer membrane component, is a key mediator of septic shock.
- Disseminated intravascular coagulation (DIC) is a severe complication of gram-negative bacterial infections, often linked to endotoxin.
- Platelet microvesicles, released during platelet activation, are implicated in hemostasis and potentially DIC, but are typically undetectable by standard clinical counters.
Purpose of the Study:
- To investigate the in vivo effect of endotoxin on platelet microvesicle formation.
- To correlate platelet microvesicle levels with gram-negative bacterial sepsis and endotoxin exposure.
Main Methods:
- Flow cytometry was employed to quantify platelet microvesicles.
- Analysis was performed on clinical samples from patients with gram-negative bacterial sepsis.
- A porcine model was used to study the direct effects of endotoxin infusion on microvesicle generation.
Main Results:
- Elevated levels of platelet microvesicles were observed in patients diagnosed with gram-negative bacterial sepsis.
- Endotoxin infusion in pigs resulted in a significant increase in platelet microvesicle formation, up to fourfold the baseline levels.
- Increased coagulation activity is associated with these endotoxin-induced microvesicles.
Conclusions:
- Endotoxin exposure is a significant initiator of platelet microvesicle formation in vivo.
- The formation of platelet microvesicles, associated with heightened coagulation, may be a direct consequence of endotoxin's presence.
- These findings suggest a mechanism by which endotoxin contributes to the pathogenesis of DIC during gram-negative bacterial infections.
