1234 PRO-APOPTOTIC MIR-34A/SIRT1/P53 PATHWAY IN NAFLD PATIENTS AND TARGETING BY URSODEOXYCHOLIC ACID IN RAT LIVER

Abstract

histology was graded and staged according to the Kleiner system. Hepatic triglycerides were quantified, and qPCR/Western blotting used to assess inflammation, fibrosis and lipid metabolism. Hepatic (oval) cell response was assessed by pan-cytokeratin (panCK) and Sox9 immunohistochemistry with morphometric analysis. Results: ALIOS fed mice developed lobular inflammation/ballooning by 6m and F3 fibrosis by 12m. By 6m, 5aR1 mice fed ALIOS diet demonstrated greater steatosis histologically (median Kleiner steatosis score; 3 vs 1), and biochemically (mean hepatic triglyceride; 93.1 vs 62.4 nmol/mg, p < 0.01) than WT mice fed ALIOS diet. There was no difference in inflammation or fibrosis. 5aR1 mice had reduced carnitine palmitoyl transferase-1a mRNA expression (p < 0.05), and increased acetyl-CoA carboxylase protein expression, consistent with decreased fatty acid b-oxidation and increased de novo lipogenesis. Focal hepatocellular lesions consistent with dysplasia/hepatocellular carcinoma developed after 12m ALIOS diet in 5/10 WT mice, with none developing in 5aR1 mice. Dysplastic/hepatocellular carcinoma lesions expressed the oval cell marker Sox9. Hepatic oval cell proliferation increased after ALIOS diet, but was attenuated in 5aR1 compared to WT mice (mean surface area panCK positive; 0.62% vs. 0.94%; Sox9 positive cells per view; 60 vs. 76/field of view respectively). Conclusions: 5aR1 deficiency promotes hepatic steatosis, but protects against the development of NASH-related dysplasia/hepatocellular carcinoma and reduces hepatic oval cell proliferation. Prolonged ALIOS diet is a unique murine model for studying NASH-related oval cell proliferation and hepatocarcinogenesis in the absence of cirrhosis. These data support a role of 5aR1 in hepatocarcinogenesis associated with NASH.