studies

684A AASLD ABSTRACTS HEPATOLOGY, October, 2015
lipopolysaccharides (LPS) contained in normal portal blood
are one of the factors about the development of NASH. Two
major pathway for LPS have been suggested in some studies,
which are referred to as MyD88-dependent and –independent
pathways. We aimed to determine the effects of sitagliptin on
the development of LPS-induced NAFLD in ob/ob mice with
diet-induced obesity and T2DM. Methods: Five-week-old male
ob/ob mice, which develop T2DM and NAFLD by taking a
high-carbohydrate diet (HCD), were divided into a group in
which a HCD was given for 8 weeks and treated with LPS
(n=6) as controls (Control group), and another in which a HCD
added with 0.0018% sitagliptin was given for 8 weeks and
treated with LPS (n=6) (Sitagliptin group). Results: Histological
examination demonstrated that this protocol induced steatosis
in the livers of two group mice, however severe fatty droplets
were significantly observed in Control group, compared
with Sitagliptin group. Sitagliptin group showed a decrease
in serum ALT and triglyceride, in addition, hepatic mRNA
expression levels of SREBP-1c, FAS and peroxisome PPARγ
were decreased in Sitagliptin group. Furthermore, Sitagliptin
inhibits the mRNA expression levels of proinflammatory gene
such as TNF-α. Interestingly, hepatic mRNA expression levels of
MyD88 and NFκB were decreased in Sitagliptin group. These
finding coincided with histological findings and the results of
biochemical examination. Conclusion: Our findings indicated
that sitagliptin could be preventative drug for the development
of LPS-induced NAFLD and MyD88-dependent pathway.
Disclosures:
The following authors have nothing to disclose: Keisuke Yokohama, Shinya
Fukunishi, Sanomura Makoto, Akira Asai, Yasuhiro Tsuds, Kazuhide Higuchi
967
DSS colitis has tumorinogenesis and fibrogenesis in choline-deficiency
and high-fat diet induced NASH mouse
model
Koichi Achiwa, Masatoshi Ishigami, Yoji Ishizu, Teiji Kuzuya,
Takashi Honda, Kazuhiko Hayashi, Yoshiki Hirooka, Hidemi Goto;
Gastroenterology and Hepatology, Nagoya Univercity Graduate
School of Medicine, Nagoya, Japan
Background and Aim Non-alcoholic steatohepatitis (NASH)
patients progress to liver cirrhosis and even hepatocellular carcinoma(HCC).
Several line of evidence indicated that accumulation
of lipopolysaccharide (LPS) plays a contributory role in
the pathogenesis HCC by eliciting proinflammatory response in
the liver. Moreover, it has been reported that dextran sodium
sulfate (DSS) induced colitis mouse model fed high fat diet
increased portal LPS and developed hepatic inflammation and
fibrosis. However, diet induced NASH model with carcinogenesis
require over 50 weeks or more. The purpose of this study
was to create a novel tumorigenesis in diet induced NASH
with DSS administration. Methods 20-week-age C57BL/6
mice were fed choline-deficiency and high-fat diet (CDHF) for
4 and 12 weeks. DSS group was fed CDHF and 1% DSS in
the drinking water intermittently. On the other hand control
group was fed CDHF and free water supply. We evaluated the
liver tumorigenesis. Hepatic lipid was measured and inflammatory
and fibrosis factors and histological changes were evaluated.
Results Exposure of DSS led to increase mucosal change
such as crypt loss and increase of inflammatory cells in colon.
Accordingly, the histological score significantly increased in
DSS group than control group. But a few colon tissues were
increased inflammatory cells at 12 week in control group.
CDHF led to slightly cause intestinal inflammation. Portal LPS
levels were increased in DSS group comparing with control
group at 4 week, whereas there was no significant difference
in both groups at 12week. Hepatic triglyceride, total and free
cholesterol were increased in the DSS group comparing with
control group at 4 week, whereas there was no significant
difference in both groups at 12 week. Both groups showed
severe macrovesicular steatosis in liver histology. Serum total
bilirubin levels were significantly higher in DSS group than that
in control group. Serum transaminase levels are higher in DSS
group than that in control group. A large number of lobular
inflammatory cells were seen in DSS group. The image analysis
showed significant elevation of F4/80 staining positive area in
DSS group comparing with control group. Fibrosis is increased
in DSS group compared to control group. Liver tumors were
developed in the DSS group of 12-week, while tumor was not
found in the DSS group of 4-week and in the control group.
One of tumors showed highly differentiated hepatocellular carcinoma.
Conclusions DSS administration developed liver tumors
in CDHF induced NASH mouse at the short term. Induction of
intestinal inflammation in NASH may promote hepatic tumorigenesis.
Disclosures:
Hidemi Goto - Grant/Research Support: MSD, Roche, Bayer, Bristol-Myers, Eisai,
Ajinomoto, Otsuka, Astra, Tanabe, Takeda
The following authors have nothing to disclose: Koichi Achiwa, Masatoshi Ishigami,
Yoji Ishizu, Teiji Kuzuya, Takashi Honda, Kazuhiko Hayashi, Yoshiki
Hirooka
968
Inhibition of Mitophagy in Non-alcoholic Steatohepatitis
lead to Apoptosis and Inflammation
Muhammad Sohail 1 , Seong-Jun Kim 2 , Aleem Siddiqui 2 ; 1 GASTRO-
ENTEROLOGY, university of California, San Diego, CA; 2 Infectious
Disease, University of California, San Diego, CA
Background: Fatty liver is benign but it can progress to Non-Alcoholic
Steatohepatitis (NASH) and liver cirrhosis. Mitochondria
are dynamic organelles that constantly undergo fission,
fusion, and mitophagy to facilitate mitochondrial quality control,
which is crucial for maintaining cell viability and bioenergetics.
Mitochondrial fission/fragmentation is mediated
by recruitment of cytosolic Drp1 to the mitochondria forming
spirals that constrict both the inner and outer mitochondrial
membranes. Drp1 recruitment to mitochondria is regulated by
phosphorylation and dephosphorylation of respective serine
residues by putative kinases and phosphatases. Mitochondrial
dynamics is tightly regulated in response to alterations
in cellular physiology and its dysfunction occurs in NASH.
Methods Palmitic acid (PA) is able to reproduce in vitro model
for fatty liver disease. To investigate the mitochondrial fission
and mitophagy, the human hepatoma Huh7 cells cultured in
the presence or absence of PA were observed by confocal
microscope. PA-induced stimulation and mitochondrial translocation
of dynamin-related protein 1 (Drp1) and Parkin, two
key factors of mitochondrial fission and mitophagy, were analyzed
by Western blot using purified mitochondria fraction
and confocal microscope. The liver tissues extracted from highfat
diet-fed C57BL/6 mice and biopsy samples from Human
NASH patients were also used for analysis of Drp1 and Parkin
activation. Small interfering RNA-mediated Drp1 and Parkin
silencing strategy was further employed for further analysis of
PA-induced mitochondrial fission and mitophagy and alteration
in inflammatory response. Results: PA stimulated Drp1 gene
expression and induced mitochondrial translocation of Drp1
via promoting both its phosphorylation (Ser616) and dephosphorylation
(Ser637) followed by mitochondrial fission. These
results were confirmed in liver tissue extracted from high-fat
diet-fed C57BL/6 mice and also in human NASH liver biopsy
tissue. While PA induced Parkin gene expression, mitophagy