Summary
The acute respiratory distress syndrome (ARDS) is a serious complication of sepsis.
To evaluate the role of the coagulation system in the pathogenesis of ARDS in sepsis,
we examined the effects of the administration of a synthetic plasma kallikrein specific
inhibitor (PKSI) and of active-site blocked factor VIIa (DEGR-VIIa) on the pulmonary
vascular injury induced by E. coli endotoxin (ET) in rats. Administration of PKSI prevented the pulmonary vascular injury
induced by ET as well as pulmonary histological changes in animals administered ET,
but it did not affect the intravascular coagulation. The opposite effect was seen
with DEGR-VIIa, which prevented the intravascular coagulation but not the pulmonary
vascular injury. PKSI did not inhibit the activation of the complement system induced
by ET leading to the activation of neutrophils.
Findings suggest that PKSI may prevent the pulmonary vascular injury induced by ET
by inhibiting kallikrein, which activates the neutrophils. The intrinsic pathway of
coagulation may be more important than the extrinsic pathway in the pulmonary vascular
injury produced byET.