Characterizing Minimal Hepatic Encephalopathy: Inflammation, Metabolism and Morphophysiological Effects

POSTER PRESENTATIONS Methods: Six patients with cirrhosis (5 males; 61.3 ± 9.2 yrs; 5 Child A, 1 Child B) and six healthy volunteers (5 males; 49.8 ± 10.6 yrs) were studied between 08:00 and 19:00 on the Monday of three consecutive weeks (Conditions I, II and III, in randomized order). The following indices were obtained: hourly capillary ammonia, hourly subjective sleepiness, paper&pencil/computerized psychometry and wake electroencephalography (EEG) at 12:00, i.e. the time of the maximum expected effect of the AAC. Results: On average, patients had worse neuropsychological performance and slower/lower amplitude EEG compared to healthy volunteers in all conditions, although differences were not significant. In healthy volunteers, the AAC-related increase in capillary ammonia levels was contained by both the administration of LOLA and that of caffeine (significant differences between 10:00 and 14:00 hours; Figure). The administration of caffeine also resulted in a reduction in subjective sleepiness and in the amplitude of the EEG on several frontal/temporal-occipital sites ( p < 0.05 on paired t test). Changes in ammonia levels, subjective sleepiness and the EEG in the three conditions were considerably less obvious in patients. Conclusions: Both LOLA and caffeine contained the AAC-induced increase in capillary ammonia, especially in healthy volunteers. Caffeine also counteracted the AAC effects on sleepiness/EEG amplitude. The association of ammonia-lowering and vigilanceenhancing medication in the management of HE is worthy of further study. M. G. holds a research post-doctoral fellowship from Gobierno de Extremadura [ jointly financed by the European Regional Development Fund (ERDF); ref. PO14013]. FRI-019 CHARACTERIZING MINIMAL HEPATIC ENCEPHALOPATHY: INFLAMMATION, METABOLISM AND MORPHOPHYSIOLOGICAL EFFECTS N. Arias1,2, M. Mendez2,3, E. Gómez-Lázaro4, A. Azpiroz4, J.L. Arias2,3. 1 University of Cambridge, Cambridge, United Kingdom; 2Ineuropa, Instituto de Neurociencias del Principado de Asturias; 3University of Oviedo, Oviedo; 4Basque Country University, San Sebastian, Spain E-mail: [email protected] Background and Aims: Although often not considered clinically relevant and, therefore, not diagnosed or treated, minimal hepatic encephalopathy (MHE) has been shown to affect quality of life and daily functioning. To discover early impairments involved in MHE, we studied one of its precipitating factors, portal hypertension. Methods: The triple portal vein ligation method was used to create an animal model of an early developmental phase of HE. Two groups of animals were used: a SHAM (sham-operated) group (n = 13) and a portal hypertension (PH) group (n = 13). Learning was assessed on a stimulus–response task. Brain metabolic activity was studied with cytochrome c-oxidase histochemistry (C.O.). Neuronal nuclear volume was assessed by nucleator probe; the number of glial fibrillary acidic protein-immunoreactive astrocytes (GFAP-IR) and proinflammatory mediators were measured. Results: The results revealed that the PH group was not able to successfully complete the stimulus-response task, in contrast to the SHAM group. Brain metabolism revealed decreased C.O. activity in the ventral striatum. The PH group showed lower density of GFAP-IR and an increase in the tumor necrotic factor-α (TNF-α). The PH group showed decreased neuronal nuclear volume in the dorsal striatum. On the contrary, increased neuronal nuclear volume was found in the ventral striatum. Conclusions: For the first time, a relationship has been established between inflammation, astrocytic and neural damage, and brain metabolic impairment in a model of MHE. Disruption of the striatum and related structures was highlighted as the main target in early stages of HE. A simple task was presented to assess the subtle impairments found in the clinic. This could provide fresh insights into the development of new tools for the assessment of MHE. S450

FRI-020 ADAR1 INHIBITS THE PROGRESSION OF HEPATIC FIBROSIS VIA IL6 EXPRESSION REGULATION S. Oren1,2, P. Kagan1,3, M. Sultan3, M. Safran3, Z. Ben-Ari1,3. 1The Sackler School of Medicine, Tel Aviv University, Tel-Aviv; 2Cancer Research Center; 3Liver Disease Center, Chaim Sheba Medical Center, Tel-Hashomer, Israel E-mail: [email protected] Background and Aims: Hepatic Stellate Cells (HSC) plays an essential role in the progress of hepatic fibrosis. As a result of hepatic injury, HSCs undergo activation from a quiescent cell to a myofibroblast-like cell characterized by alpha-smooth muscle actin (αSMA) upregulation and extracellular matrix secretion. Adenosine-to-inosine conversion (A-to-I RNA editing), a posttranscriptional modification on RNA, contributes to extensive transcriptome diversity. A-to-I editing is a hydrolytic deamination process, catalyzed by adenosine deaminase acting on double-stranded RNA (ADAR) family of enzymes. ADARs are essential for normal mammalian development, and disturbance in RNA editing has been implicated in various pathologic disorders. Recently, studies have indicated that liver specific ADAR1 knockout (KO) mice showed severe structural and functional damage to the liver, progression to hepatic fibrosis and Interleukin 6 (IL6) up regulation. Aim: To examine the direct role of ADAR1 depleted hepatocyte in the progression of hepatic fibrosis and their relationship with IL6. Methods: Primary HSCs were purified from mice liver. The purified HSCs were incubated in medium of Hepatoma cell line (HepG2) transfected with either ADAR1 (ADAR1 KD) siRNA or control siRNA. The degree of HSCs activation was analyzed by the expression of αSMA and Col1a. Level of IL6 in ADAR1 KD HepG2 cells was determined by qRT-PCR and ELISA assay. The effect of IL6 was evaluated in primary HSCs incubated in media of IL6 and ADAR1 double KD HepG2 cells. Results: Incubation of primary HSCs in medium collected from ADAR1 KD HepG2 cells increased the levels of αSMA and Col1a expression in comparison with medium from ADAR1 expressing cells. The depletion of ADAR1 from HepG2 cells led to increase in IL6 RNA expression level and the secretion of IL6 into the medium. In addition, we have demonstrated the ADAR1 KD HepG2 cells that did not express IL6 could not activate HSCs as measured by the expression of αSMA and Col1a. Conclusions: Condition medium from ADAR1 KD HepG2 cells directly affect the activation of primary HSCs from quiescent cell to a myofibroblast-like cell. Furthermore, we have shown that HSCs activation is mediated by IL6 expression. Our findings may provide novel insight of the role of ADAR1 via IL6 expression regulation in the pathogenesis of liver fibrosis thus ADAR1 may serve as a potential target for therapeutic intervention in hepatic fibrosis. FRI-021 COAGULATION OF PATIENTS WITH CIRRHOSIS REVISITED USING AN ASSAY TAKING INTO ACCOUNT ENDOTHELIAL CELLS: THROMBIN GENERATION IS QUICKER BUT LESS ABUNDANT P.-E. Rautou1, C. Kuadjovi2, L. Elkrief1, L. Venisse3, L. Boudaoud2, F. Durand1, D. Valla1, N. Ajzenberg3, E. De Raucourt2. 1DHU Unity, Service d’hépatologie; 2Service d’hématologie biologique, Hôpital Beaujon, Clichy; 3Service d’hématologie biologique, Hôpital Bichat, Paris, France E-mail: [email protected] Background and Aims: In patients with cirrhosis, concerns with coagulation disorders have changed from a traditional view of increased bleeding to that of increased thrombosis. The concept of a hypercoagulable state in patients with cirrhosis is based on thrombin-generation tests performed on plasma samples in the presence and absence of thrombomodulin, added to mimic endothelial cells action. However, endothelial cells modulate coagulation by mechanisms independent from thrombomodulin,

Journal of Hepatology 2016 vol. 64 | S425–S630