studies

HEPATOLOGY, VOLUME 62, NUMBER 1 (SUPPL) AASLD ABSTRACTS 513A
Disclosures:
David Jones - Consulting: Intercept, Pfizer, Novartis; Speaking and Teaching:
Falk, Shire
The following authors have nothing to disclose: Claire Hardie, Kile J. Green,
Sarah Pagan, Jessica K. Dyson, Lucy J. Walker, Laura Jopson, John G. Brain
612
Vitamin A deficiency promotes hepatic expansion of
resident (Kupffer cells) and peripheral (Gr hi ) macrophages
leading to excessive liver damage in rats with
obstructive cholestasis
Ali Saeed, Mark Hoekstra, Martijn O. Hoeke, Janette Heegsma,
Han Moshage, Klaas Nico Faber; Department of Gastroenterology
and Hepatology, University Medical Center Groningen, Groningen,
University of Groningen, The Netherlands, Groningen, Netherlands
Vitamin A deficiency (VAD) is associated with chronic liver diseases
(CLD), including biliary atresia, primary biliary cirrhosis,
primary sclerosing cholangitis and non-alcoholic fatty liver disease.
Serum and/or hepatic retinol levels negatively correlate
with disease progression. Previously, we found that VAD rats
shown much more severe liver damage when exposed to bile
duct ligation (BDL) compared to rats with sufficient vitamin A
(VAS) levels, but the mechanisms involved remain unresolved
so far. Vitamin A has potent anti-inflammatory properties and
therefore we investigated its effect on resident (Kupffer cells)
and peripheral (Gr hi ) macrophages in vitro and in vivo. Weaning
male Wister rats were fed either a VAS or a VAD diet for
14-16 weeks, followed by BDL for 1, 2, 4, 7 days. One group
subjected to 7-day BDL received retinyl-palmitate therapy. Liver
damage marker were analysed in serum, and liver tissue was
analysed with Q-PCR, Western blotting and immunohistochemistry.
Primary rat Kupffer cells and THP-1 (human Leukemic
monocyte cell line) cells were exposed to VAS and VAD conditions
and cytokine expression was analysed by Q-PCR. CD68
(general macrophage marker) and CD11b (peripheral macrophages)
positive cells were significantly increased in livers
of VAD rats after 4- and 7-day BDL as compare to VAS-BDL
control livers, and was associated with increased plasma γGT
levels and expression of liver fibrosis makers, such as α-SMA
and Collagen1A1. All these features were strongly suppressed
in VAD-BDL rats receiving vitamin A therapy. In line, expression
of the macrophage chemoattractant Ccl2 was significantly
increased in VAD-BDL livers and suppressed by vitamin A therapy.
VAD-BDL livers showed increased expression of proinflammatory
and profibrotic markers, such as iNos, Tnf-α, Il-1,
Il-6, Cox-2, Tgf-β and vitamin A therapy decreased this inflammatory
response. In vitro, VAD (RPMI with lipid-stripped serum)
caused an inflammatory polarization in primary Kupffer cells
and PMA-activated-THP-1 cells as compare to control cells and
increased the expression of inflammatory markers, including
iNos, Tnf-α, Il-1, Il-6, Cox-2. The vitamin A metabolites, 9-cis
retinoic acid and all trans retinoic acid, reduced expression
of these inflammatory markers. In conclusion, vitamin A deficiency
promotes hepatic macrophage expansion in obstructive
cholestasis, which show an aggressive pro-inflammatory and
pro-fibrotic phenotype that aggravates liver damage, but is
effectively prevented by vitamin A supplementation. This study
supports an direct role of vitamin A in preventing excessive
liver damage in patients with chronic liver diseases.
Disclosures:
The following authors have nothing to disclose: Ali Saeed, Mark Hoekstra, Martijn
O. Hoeke, Janette Heegsma, Han Moshage, Klaas Nico Faber
613
The Modulation of Co-stimulatory Molecules by Circulating
Exosomes in Primary Biliary Cirrhosis
Takashi Tomiyama 1,2 , Guo-Xiang Yang 1 , Ming Zhao 4 , Weici
Zhang 1 , Hajime Tanaka 1,5 , Jing Wang 4 , Patrick S. Leung 1 , Kazuichi
Okazaki 2 , Xiao-Song He 1 , Quiajin Lu 4 , Ross L. Coppel 3 ,
Christopher L. Bowlus 1 , M. Eric Gershwin 1 ; 1 Internal Medicine,
University of California, Davis, CA; 2 Third Department of Internal
Medicine, Division of Gastroenterology and Hepatology, Kansai
Medical University, Osaka, Japan; 3 Department of Microbiology,
Monash University, Melbourne, VIC, Australia; 4 Department of
Dermatology, The Second Xiangya Hospital, Central South University,
Hunan, China; 5 Department of Gastroenterology and
Metabolism, Nagoya City University Graduate School of Medical
Sciences, Nagoya, Japan
Background: Exosomes are secreted intracellular microparticles
that can induce antigen-specific immune responses and potentially
trigger inflammation. The role of exosomes in autoimmunity
has drawn significant attention because of their ability to
modulate cell-to-cell communications in part by their ability to
regulate cytokine and chemokine activation. However, the contribution
of exosomes in autoimmune cholangitis has not been
addressed. Herein, we studied the effect of exosomes from
patients with primary biliary cirrhosis (PBC) and healthy controls
(HCs) on cytokine production and co-stimulatory molecule
expression in peripheral mononuclear cell populations. Further,
we also determined the micro RNA (miRNA) profiles of circulating
exosomes and verified with an independent cohort. Methods:
Exosomes were purified from plasma from 28 patients
with PBC and 25 HCs. Their effect on cytokine production and
co-stimulatory molecule expression in mononuclear cell populations
were examined using an ex vivo system. In addition, miR-
NAs profile of the exosomes was measured by Agilent Human
miRNA (8*60K) V19.0 microarray. miRNAs with a level of
2-fold or larger difference between groups were considered
differentially expressed and verified using isolated exosomes
from additional groups of PBC and HC using a Taqman PCR
assay for individual miRNAs. Further, we examined whether
the levels of these exosomal miRNAs correlated with severity of
disease. Results: Our data showed that circulating exosomes
from PBC are taken up by antigen presenting cells (APCs) and
affect the expression of cell surface co-stimulatory molecules
CD80, CD86 and CD40 on APCs. Circulating exosomes in
PBC contain altered patterns of miRNA expression with 9 miR-
NAs significantly up-regulated and another 9 miRNAs significantly
down-regulated when compared to the HC. Conclusions:
Exosomes significantly alter co-stimulatory molecule expression
on antigen presenting cell populations and there were differences
of miRNA expression in circulating exosomes in patients
with PBC. The rigorous dissection of exosomes and their constituents
is an important component for analysis to understand the
nature of the pathogenic effects produced during the natural
history of autoimmune cholangitis.
Disclosures:
Christopher L. Bowlus - Advisory Committees or Review Panels: Gilead Sciences,
Inc; Grant/Research Support: Gilead Sciences, Inc, Intercept Pharmaceuticals,
Bristol Meyers Squibb, Takeda, Lumena, Merck; Speaking and Teaching: Gilead
Sciences, Inc
The following authors have nothing to disclose: Takashi Tomiyama, Guo-Xiang
Yang, Ming Zhao, Weici Zhang, Hajime Tanaka, Jing Wang, Patrick S. Leung,
Kazuichi Okazaki, Xiao-Song He, Quiajin Lu, Ross L. Coppel, M. Eric Gershwin