Antithrombin-III treatment limits disseminated intravascular coagulation in endotoxemia

Gram-negative septicemia/endotoxemia remains a serious clinical disorder that is often complicated by disseminated intravascular coagulation (DIC). Plasma antithrombin-III (AT-III) levels usually decrease during gram-negative septicemia/endotoxemia, and even moderate decreases in this major inhibitor of the coagulation system are associated with serious DIC. We demonstrated in an earlier study that prophylactic treatment of rats with 250 U/kg of AT-III followed by endotoxin challenge markedly attenuates DIC, indices of organ damage, and metabolic dysfunction. The present study was to determine whether treatment with 250 U/kg AT-III 1 hr after endotoxin challenge would be similarly efficacious. Rats treated with 250 U/kg of AT-III inactivated by human sputum elastase (ATX) served as protein controls. Blood samples for analysis were obtained 4 hr after AT-III or ATX treatment (5 hr after endotoxin challenge). Rats in the ATX treatment group exhibited abnormalities characteristic of endotoxemia, i.e., decreased fibrinogen levels and platelet counts, increases in prothrombin time and activated partial thromboplastin time, elevated serum glutamic oxaloacetic transaminase (SGOT) and alkaline phosphatase (AKP), and hypoglycemia. Treatment with AT-III markedly and significantly (P less than .05) attenuated all of these abnormalities, although survival was not increased. This study strongly suggests that supplementation of plasma AT-III is efficacious after the development of sepsis, although not as efficacious as prophylactic treatment.