1E). Compared with pCI-Ctrl–treated animals, pCI-Pbef1–treated animals displayed significantly

elevated levels of hepatic mRNA expression of CXCL-1, IL-6, and IL-1β after ConA challenge. No difference was observed in liver TNFα, IFNγ, and IL-10 inductions (Fig. 3F). The experiments performed in the ConA model were repeated in D-galactosamine/LPS–induced experimental hepatitis. Disease outcome was compared between pCI-Pbef1– and pCI-Ctrl–injected animals. Again, overexpression of PBEF by hydrodynamic perfusion deteriorated liver damage in D-galactosamine/LPS-induced hepatitis as demonstrated by significantly elevated liver enzymes (Supporting Fig. 2A) and increased hepatic mRNA expression of CXCL-1 and IL-1β (Supporting Fig. 2B) when compared with pCI-Ctrl–injected selleck compound mice. The above studies indicated that Nampt is strongly up-regulated during experimental hepatitis as well as in human chronic liver disease. Therefore, FK866—a highly specific, noncompetitive inhibitor of Nampt—was used to block Nampt in vivo. Importantly, whereas vehicle treatment did not affect

the course of ConA hepatitis, the preadministration of FK866 resulted in reduced ConA-induced liver toxicity. By the time of liver explantation, control livers appeared macroscopically more severely affected with abundant subcapsular necrotic areas (data not shown). Upon examination of hematoxylin and eosin–stained liver sections, vehicle-treated control mice showed more extensive and more numerous find more necrotic lesions (Fig. 4B) compared with FK866-treated mice (Fig. 4A). Quantification of liver necrosis revealed a 12.2-fold selleck reduction in necrotic areas (Fig. 4C). FK866-treated animals displayed a marked reduction of hepatocyte apoptosis as detected and quantified by TUNEL staining (Supporting Fig. 3A) compared with their vector-treated littermates (Supporting Fig. 3B). In support of these data, FK866-treated mice displayed a 5.1-fold decrease in AST plasma levels and a 4.2-fold decrease in ALT plasma levels (Fig. 4D). Examination of liver tissue NAD+ concentrations revealed that FK866 effectively suppressed Nampt-mediated NAD+ production. Liver

NAD+ concentrations were 6.1-fold lower in FK866 compared with vehicle-treated mice (Fig. 4E). Determination of liver cytokine expression in FK866-treated mice showed a significant reduction in the relative expression of CXCL1, IL-1β, TNFα, IFNγ, and IL-10 compared with control-treated animals (Fig. 4F). Once more, we tested FK866 in another model of acute liver failure, namely the D-galactosamine/LPS model. Again, treatment with the Nampt inhibitor protected mice from macrophage-driven D-galactosamine/LPS hepatitis, as shown by significant decreases of plasma AST and ALT activities (Supporting Fig. 3C). Again, treatment with FK866 was associated with a significant decrease in hepatic NAD concentration (Supporting Fig. 3D).