Plasma Kallikrein and Hageman Factor in Gram-Negative Bacteremia

Abstract

Activation of the plasma kallikrein system as evidenced by increased spontaneous activity resembling the substrate specificity of plasma kallikrein was observed in a fatal case of Gram-negative bacteremic shock complicated by consumption coagulopathy. In other nonfatal cases with Gram-negative bacteremic hypotension evidence of activation of kallikrein with concomitant decrease in both kallikrenogen and kallikrein inhibitor was found. Bacteremic hypotension was associated with more pronounced changes in the kallikrein system than in normotensive bacteremia, but similar changes did not occur in hypotension due to blood loss. Activation of the plasma kallikrein system was produced by injection of endotoxin in mice and rats. These data suggest that bacterial products may act through Hageman factor to activate the kallikrein system, leading to hypotension.