The role of the hemostatic system in murine liver injury induced by coexposure to lipopolysaccharide and trovafloxacin, a drug with idiosyncratic liability

The use of the fluoroquinolone antibiotic trovafloxacin (TVX) was severely restricted in 1999 due to its association with idiosyncratic hepatotoxicity. Previously, we reported that a nontoxic dose of TVX interacts with a nontoxic dose of lipopolysaccharide (LPS) to cause robust hepatocellular injury in mice. This interaction with LPS was not seen in mice treated with levofloxacin (LVX), a fluoroquinolone not associated with hepatotoxicity in people. TVX/LPS-coexposure caused an increase in plasma alanine aminotransferase (ALT) activity as early as 4.5 h after LPS administration which progressed through 15 h. We examined the role of the hemostatic system in TVX/LPS-induced liver injury. At the onset of liver injury, coexposure to TVX/LPS, but not exposure to TVX, LVX, LPS or LVX/LPS, caused increased plasma concentration of thrombin–antithrombin dimers and decreased plasma circulating fibrinogen. LPS treatment induced a small increase in plasma plasminogen activator inhibitor-1 (PAI-1) concentration, and TVX pretreatment enhanced this effect. TVX/LPS coexposure also resulted in hepatic fibrin deposition. Anticoagulant heparin administration reduced TVX/LPS-induced hepatic fibrin deposition and liver injury. PAI-1−/− mice treated with TVX/LPS exhibited similar fibrin deposition to wild-type mice but had significantly reduced hepatocellular injury. PAI-1−/− mice, but not heparin-treated mice, had reduced plasma concentrations of several cytokines compared to TVX/LPS-treated controls. In summary, TVX/LPS-coexposure caused an imbalance in the hemostatic system, resulting in thrombin activation increased, plasma concentration of PAI-1 and hepatic fibrin deposition. Both thrombin activation and PAI-1 play critical roles in the progression of TVX/LPS-induced liver injury, but through different modes of action.