Rust, Christian; Bauchmüller, Kris Benjamin; Berndt, C.; Vennegerts, Timo; Fickert, P.; Fuchsbichler, A.; Beuers, Ulrich
Sulfasalazine reduces bile acid induced apoptosis in human hepatoma cells and perfused rat livers.
In: Gut, Vol. 55, Nr. 5: S. 719-727
Background: Bile acid-induced apoptosis in hepatocytes can be antagonized by NF-κBdependent survival pathways. Sulfasalazine modulates NF-κB in different cell types. We aimed to determine the effects of sulfasalazine and its metabolites sulfapyridine and 5-aminosalicylic acid (5-ASA) on bile acid-induced apoptosis in hepatocytes.
Methods: Apoptosis was determined by caspase assays and immunoblotting, NF-κB activation by EMSA and reporter gene assays, generation of reactive oxygen species (ROS) fluorometrically, bile secretion gravimetrically and bile acid uptake radiochemically and by gaschromatography in HepG2-Ntcp cells and isolated perfused rat livers.
Results: Glycochenodeoxycholic acid (GCDCA, 75μmol/L)-induced apoptosis was reduced by sulfasalazine dose-dependently (1-1000 μmol/L) in HepG2-Ntcp cells, whereas its metabolites 5- ASA and sulfapyridine had no effect. Sulfasalazine significantly reduced GCDCA-induced activation of caspases 9 and 3. In addition, sulfasalazine activated NF-κB, and decreased GCDCA-induced generation of ROS. Bile acid uptake was competetively inhibited by sulfasalazine. In perfused rat livers, GCDCA (25 μmol/L)-induced liver injury and extensive hepatocyte apoptosis were significantly reduced by simultaneous administration of 100 μmol/L sulfasalazine: LDH and GPT activities were reduced by 82% and 87%, respectively, and apoptotic hepatocytes were observed only occasionally. GCDCA uptake was reduced by 45±5% when sulfasalazine was coadministered. However, when 50% of GCDCA (12.5 μmol/L) were administered alone, marked hepatocyte apoptosis and liver injury were again observed questioning the impact of reduced GCDCA uptake for the antiapoptotic effect of sulfasalazine.
Conclusion: Sulfasalazine is a potent inhibitor of GCDCA-induced hepatocyte apoptosis in vitro and in the intact liver.