Active Site Inhibited Factor VIIa (DEGR VIIa) Attenuates the Coagulant and Interleukin-6 and -8, but not Tumor Necrosis Factor, Responses of the Baboon to LD100Escherichia coli

Diagnostic criteria and laboratory tests for disseminated intravascular coagulation

Disseminated intravascular coagulation (DIC) is associated with organ failure and it is often fatal condition. The main underlying diseases are infection, hematological malignancy and solid cancer. DIC is subclassified into overt DIC and non-overt DIC. The International Society on Thrombosis and Haemostasis (ISTH) and the Japanese Association for Acute Medicine (JAAM) published the diagnostic criteria for DIC after several recent clinical trials. These diagnostic criteria are modified versions of the Japanese Ministry of Health, Labor and Welfare (JMHLW) criteria. The JAAM diagnostic criteria demonstrated excellent sensitivity for mortality but low specificity. The mechanisms of onset of DIC vary based on the underlying diseases, and depend on tissue factor, cytokines, etc. Early diagnosis and early treatment for DIC are important, and the use of hemostatic molecular markers is necessary to successfully make an early and rapid diagnosis. The mortality of DIC might be improved by the administration of recombinant activated protein C or recombinant thrombomodulin. Further investigation to improve the mortality of DIC is required, including new methods for diagnosing and treating the disease.

Blockade of tissue factor: treatment for organ injury in established sepsis

Blockade of tissue factor before lethal sepsis prevents acute lung injury and renal failure in baboons, indicating that activation of coagulation by tissue factor is an early event in the pathogenesis of acute lung injury and organ dysfunction. We hypothesized that blockade of tissue factor would also attenuate these injuries in established sepsis by prevention of further fibrin deposition and inflammation. Twelve male baboons received heat-killed Escherichia coli intravenously followed 12 hours later by live E. coli infusion. Six animals were treated 2 hours after the live bacteria with site-inactivated Factor VIIa, a competitive tissue factor inhibitor, and six animals were vehicle-treated sepsis control subjects. Animals were ventilated and monitored for 48 hours. Physiologic and hematologic parameters were measured every 6 hours, and pathologic evaluation was performed after 48 hours. Animals treated with site inactivated Factor VIIa had less severe lung injury, with preserved gas exchange, better lung compliance and histology scores, and decreased lung wet/dry weight. In treated animals, urine output was higher, metabolic acidosis was attenuated, and renal tubular architecture was protected. Coagulopathy was attenuated, and plasma interleukin-6, interleukin-8, and soluble tumor necrosis factor receptor-1 levels were significantly lower in the treated animals. These results show that blockade of coagulation attenuates acute lung and renal injury in established Gram-negative sepsis accompanied by antiinflammatory effects of therapy.

The in vivo kinetics of tissue factor messenger RNA expression during human endotoxemia: relationship with activation of coagulation

Triggering of the tissue factor (TF)-dependent coagulation pathway is considered to underlie the generation of a procoagulant state during endotoxemia. To determine the in vivo pattern of monocytic TF messenger RNA (mRNA) expression during endotoxemia, 10 healthy volunteers were injected with lipopolysaccharide (LPS, 4 ng/kg) and blood was collected before and 0.5, 1, 2, 3, 4, 6, 8, and 24 hours after LPS administration. Total blood RNA was isolated and amplified by NASBA (nucleic acid sequence-based amplification), followed by quantitation of TF mRNA by an electrochemiluminescence (ECL) assay. To compare the pattern of coagulation activation with the kinetics of monocytic TF mRNA expression, we measured plasma levels of markers of thrombin generation, thrombin-antithrombin (TAT) complexes, and prothrombin fragment 1 + 2 (F1 + 2). Baseline value (mean ± SEM) of the number of TF mRNA molecules per monocytic cell was 0.08 ± 0.02. A progressive and significant (P < .0001) increase in TF expression was observed after LPS injection (+0.5 hour: 0.3 ± 0.1, +1 hour: 1.3 ± 0.9, +2 hours: 4.1 ± 0.9), peaking at +3 hours (10 ± 1.9 TF mRNA molecules per monocyte). As TF mRNA levels increased, thrombin generation was augmented. Peak levels of TAT and F1 + 2 were reached later (at t +4 hours) than those of TF mRNA. TF mRNA, TAT, and F1 + 2 levels returned to baseline after 24 hours. In conclusion, we used a NASBA/ECL-based technique to quantify TF mRNA in whole blood during human endotoxemia and observed a 125-fold increase in TF mRNA levels. Our data demonstrate a pivotal role for enhanced TF gene activity in the activation of coagulation after LPS challenge.