Protection against disseminated intravascular coagulation and death by antithrombin-III in the Escherichia coli endotoxemic rat.

Gram-negative septic shock remains a major clinical problem. One frequently encountered complication of sepsis is disseminated intravascular coagulation (DIC). The present study was to determine in an Escherichia coli endotoxemia awake rat model the efficacy of antithrombin-III (AT-III) prophylaxis and to explore the role of DIC in the pathogenesis of endotoxemia. We demonstrated that DIC occurs very early, before the appearance of detectable serious abnormalities in cardiovascular, metabolic, and biochemical variables indicative of organ damage or dysfunction; AT-III prophylaxis significantly ameliorates DIC, as evidenced by completely preventing the fall in plasma fibrinogen concentration and significantly limiting the increases in prothrombin time and activated partial thromboplastin time after 4 hours of endotoxemia; and AT-III prophylaxis dramatically increases permanent survival. Results of this study suggest that AT-III prophylaxis is very protective above a threshold dosage in an endotoxemic rat model and that protection is in part due to ameliorating DIC. Our data also suggest that DIC occurs very early during endotoxemia and may in part be responsible for the pathogenesis of endotoxemia in the rat. We conclude that AT-III prophylaxis may be efficacious in conditions of impending DIC, such as gram-negative septicemia/endotoxemia.