Experimental Hepatocarcinogenesis

2013 Hepatology  
p<0.05) and inflammatory polyarthropathias (HR 1.32; CI 1.10-1.56; p<0.005), as compared to women without ICP. Women with diabetes mellitus seem to have an increased risk of ICP (OR 2.44; p=0.634). Conclusions: Women with ICP have increased risk to be later diagnosed with autoimmune diseases, in particular diabetes mellitus, which is in agreement with our previous observation that women with ICP are more likely to have gestational diabetes. Disclosures: The following people have nothing to
more » ... ose: Hanns-Cytoglobin (Cygb) is a 21-kDa globin expressed in hepatic stellate cells (HSC) that functions as a hypoxia sensor and gas carrier. However, its pathophysiological role in vivo remains unclear. Here, we report increased liver cancer development in Cygb-deficient (KO) mice administered either diethylnitrosamine (DEN) or a choline-deficient, L-amino-acid-defined (CDAA) diet that induces hepatosteatosis. Methods: Eight-weekold Cygb KO and wild-type (WT) mice were treated with DEN in drinking water or CDAA and its control, choline-supplemented, L-amino-acid-defined (CSAA) diet for 8-36 weeks. Macroscopic and microscopic observations were made. Gene expression and intracellular signaling pathways were analyzed. Oxidative stress, antioxidant, and macrophage deletion treatments were also performed in parallel with Cygb siRNA or CYGB overexpressing vectors transfection. Results: Model 1: 25 or 0.05 ppm DEN treatment for 25 or 36 weeks induced liver tumor formation in 100 or 43% of Cygb-KO mice, respectively, compared to 44 or 0% of WT mice. In KO mice, there was liver fibrosis, increased inflammatory gene expression and augmented oxidative stress. Model 2: with as little as 8 weeks of CDAA treatment, Cygb-KO mice showed marked steatohepatitis, which resulted in advanced fibrosis at 16 weeks, compared with the WT. Surprisingly, at 32 weeks, 100% of Cygb-KO mice of both genders developed liver cancer, compared to 0% in WT mice. At all time points, there was severe inflammation associated with activated liver cancer pathways in the Cygb-KO mice. Cygb-KO HSC (HSC isolated from Cygb-KO mice) and Cygb siRNA-transfected WT-HSC were both primed, as indicated by markedly increased expression of αSma, collagen 1α1, Tnfα, Tgfβ1, Il-1β, Il-6, Ccl-2, Ccl-3, and Ccl-4 mRNA and superoxide production compared to controls. Oxidative stress and antioxidant defense PCR arrays showed altered expression of 31 genes involved in the metabolism of reactive oxygen species in Cygb-KO mice. N-acetyl cysteine treatment for 2 weeks eliminated the oxidative stress in CDAAfed Cygb-KO mice in vivo, and in cultures of isolated Cygb-KO HSC. Macrophage deletion after 8 weeks of CDAA feeding reduced the inflammatory reaction, oxidative stress, and fibrosis in Cygb-KO mice. Moreover, Hep-G2 cells overexpressing CYGB showed decreased proliferation under hypoxia compared with plasmid controls, as well as downregulated expression of fibrosis-and angiogenesis-related genes. Conclusion: Cygb deficiency promotes liver cancer development via HSC priming and augmented inflammation, local fibrosis, and oxidative stress. Disclosures: The following people have nothing to disclose:
doi:10.1002/hep.26879 fatcat:d5oo35n5nfajhlhyuqajwklmsq