Rat liver macrophages will not phagocytose fibrin during disseminated intravascular coagulation.

Disseminated intravascular coagulation was induced in rats by injection of a silver colloid suspension or thrombin. Ten min after the injection of colloid, fibrin deposits were observed light microscopically in all major organs. At 30 min, fibrin was no longer present. In rats treated with antifibrinolytics (epsilon-aminocaproic acid or Trasylol) fibrin was still present at 30 and 60 min. Interaction of fibrin with Kupffer cells was studied by electron microscopy. At 3, 10, and 20 min after the colloid injection, all fibrin occurred extracellularly, close to the surface of Kupffer cells. At 30 min, all fibrin had disappeared. In rats pretreated with antifibrinolytics, too, all fibrin was found extracellularly at 10, 30, and 60 min. Comparable results were obtained when thrombin was used to induce coagulation. It is concluded that removal of native fibrin from the circulation by Kupffer-cell phagocytosis is unlikely.