PT - JOURNAL ARTICLE AU - Erwin Biecker AU - Andrea De Gottardi AU - Markus Neef AU - Matthias Unternährer AU - Vreni Schneider AU - Monika Ledermann AU - Hans Sägesser AU - Sidney Shaw AU - Jürg Reichen TI - Long-Term Treatment of Bile Duct-Ligated Rats with Rapamycin (Sirolimus) Significantly Attenuates Liver Fibrosis: Analysis of the Underlying Mechanisms AID - 10.1124/jpet.104.079616 DP - 2005 Jun 01 TA - Journal of Pharmacology and Experimental Therapeutics PG - 952--961 VI - 313 IP - 3 4099 - http://jpet.aspetjournals.org/content/313/3/952.short 4100 - http://jpet.aspetjournals.org/content/313/3/952.full SO - J Pharmacol Exp Ther2005 Jun 01; 313 AB - Rapamycin is an immunosuppressant with antiproliferative properties. We investigated whether rapamycin treatment of bile duct-ligated (BDL) rats is capable of inhibiting liver fibrosis and thereby affecting hemodynamics. Following BDL, rats were treated for 28 days with rapamycin (BDL SIR). BDL animals without drug treatment (BDL CTR) and sham-operated animals served as controls. After 28 days, hemodynamics were measured, and livers were harvested for histology/immunohistochemistry. Liver mRNA levels of transforming growth factor (TGF)-β1, connective tissue growth factor (CTGF), platelet-derived growth factor (PDGF)-β, cyclin-dependent kinase inhibitor p27kip (p27), and cyclin-dependent kinase inhibitor p21WAF1/CIP1 (p21) were quantified by real-time polymerase chain reaction. Liver protein levels of p27, p21, p70 S6 kinase (p70s6k), phosphorylated p70s6k (p-p70s6k), eukaryotic initiation factor 4E-binding protein (4E-BP1), p-4E-BP1 (Thr37/46), and p-4E-BP1 (Ser65/Thr70) were determined by Western blotting. Portal vein pressure was lower in BDL SIR than in BDL CTR animals. Volume fractions of connective tissue, bile duct epithelial, and desmin- and actin-positive cells were lower in BDL SIR than in BDL CTR rats. On the mRNA level, TGF-β1, CTGF, and PDGF were decreased by rapamycin. p27 and p21 mRNA did not differ. On the protein level, rapamycin increased p27 and decreased p21 levels. Levels of nonphosphorylated p70s6k and 4E-BP1 did not vary between groups, but levels of p-p70s6k were decreased by rapamycin. Rapamycin had no effect on p-4E-BP1 (Thr37/46) and p-4E-BP1 (Ser65/Thr70) levels. In BDL rats, rapamycin inhibits liver fibrosis and ameliorates portal hypertension. This is paralleled by decreased levels of TGF-β1, CTGF, and PDGF. Rapamycin influences the cell cycle by up-regulation of p27, down-regulation of p21, and inhibition of p70s6k phosphorylation. The American Society for Pharmacology and Experimental Therapeutics