Summary
Tissue factor (TF) plays a critical role in the pathogenesis of disseminated intravascular
coagulation (DIC) observed in patients with septic shock. Urinary trypsin inhibitor
(UTI), a multivalent protease inhibitor, is currently used for treatment of patients
with septic shock. This study was undertaken to determine whether UTI reduces LPS-induced
coagulation abnormalities by inhibiting lipopolysaccharide (LPS)-induced expression
of TF by monocytes. UTI inhibited LPS-induced increases in both TF activities andTF
mRNA expression in monocytes without affecting the viability. Although activation
of nuclear factor-κB (NF-κB), activator protein-1 (AP-1) and extracellular signal-regulated
kinase (ERK)1/2 were shown to be critically involved in LPS-induced increases in TF
activities in isolated monocytes, UTI inhibited phosphorylation of ERK1/2 and decreased
expression of early growth response factor-1 (Egr-1) induced by LPS without affecting
the activation of NF-κB and AP-1. UTI inhibited both the expression of TF mRNA in
whole blood, increases in TF activities in mononuclear cells, and increases in serum
levels of fibrin and fibrinogen degradation products (E) in rats given LPS without
affecting the number of monocytes in the peripheral blood. Taken together these results
strongly suggested that UTI might reduce LPS-induced coagulation abnormalities in
rats by inhibiting TF expression in monocytes through inhibition of Egr-1 expression.
Keywords
Tissue factor - monocytes - Egr-1 - disseminated intravascular coagulation