Concanavalin A (con A)-induced hepatitis is an immunomediated disease in which assembly of CD4⁺ T cells and T helper (Th)1-like cytokines causes Fas-mediated liver cell death. Nitric oxide (NO) modulates Th1 response in vitro. NCX-4016 is an NO-aspirin derivative that spares the gastrointestinal tract and shares molecular targets with NO. The aim of this study was to investigate whether this NO-aspirin modulates Th1-like response induced by con A.

BALB/c mice were injected with 0.3 mg con A per mouse alone or in combination with NO-aspirin (18–100 mg/kg) or aspirin (10–55 mg/kg).

NO-aspirin, but not aspirin, caused a dose-dependent protection against liver damage induced by con A. At a dose of 100 mg/kg, NO-aspirin caused a 40%–80% reduction of interleukin (IL)-1β, IL-12, IL-18, interferon (IFN)-γ, and tumor necrosis factor α production without affecting cytokine messenger RNA expression. NO-aspirin prevented Fas, Fas ligand, and IL-2 receptor up-regulation on spleen lymphocytes and Fas ligand on hepatocytes and caused the S-nitrosylation/inhibition of IL-1β–converting enzyme–like cysteine proteases (caspases) involved in the processing and maturation of IL-1β and IL-18. IL-18 immunoneutralization prevented IFN-γ release and protected from liver injury induced by con A. In contrast to a selective caspase 1 inhibitor, zVAD.FMK, a pancaspase inhibitor, prevented IFN-γ release and protected the liver from injury.

Th1-like response induced by con A is mediated by IL-18 and requires activation of multiple caspases. NCX-4016 causes the S-nitrosylation/inhibition of caspases involved in cytokine production. Inhibition of Th1-like response is a new anti-inflammatory mechanism of action of NO-aspirin. GASTROENTEROLOGY 2000;118:404-421