IMPAIRED PLATELET-FUNCTION IN ENDOTOXEMIC PIGS ANALYZED BY FLOW-CYTOMETRY

Endotoxin or bacterial lipopolysaccharide (LPS) is a structural compon ent of Gram-negative bacteria. It is believed to be the major pathogen ic factor of Gram-negative sepsis, and may result in disseminated intr avascular coagulation and in a shock syndrome that is characterized by thrombocytopenia, leucopenia, hypotension, fever, reduced delivery of oxygen, metabolic acidosis and ultimately death. We have previously s hown that both endotoxemic pigs and patients with Gram-negative sepsis have elevated levels of platelet microvesicles in their blood, which indicates platelet activation. In this study, we have used flow cytome try and fluorescein-labeled chicken anti-human fibrinogen to evaluate the in vivo effect of endotoxin on platelet function in a porcine mode l. Endotoxin infusion in pigs caused impaired platelet function when p latelets were stimulated with adenosine-diphosphate in vitro (P < 0.00 1). We also found a similarly decreased platelet function in patients with Gram-negative sepsis. Since flow cytometry is a rapid method for determination of platelet function, this method may turn out to be a u seful tool in clinical situations. Our results may contribute to our u nderstanding of the bleeding problems that may occur in septic shock a nd in disseminated intravascular coagulation.