Exacerbated Liver Injury Research Articles

AMPKα2 knockout enhances tumour inflammation through exacerbated liver injury and energy deprivation-associated AMPKα1 activation.

Tissue damage and its associated‐inflammation act as tumour initiators or propagators. AMP‐activated protein kinase (AMPK) is activated by environmental or nutritional stress factors, such as hypoxia, glucose deprivation, and other cell injury factors, to regulate cell energy balance and differentiation. We previously have reported that AMPKα2 deficiency resulted in the energy deprivation in tumour‐bearing liver and the enhanced‐hepatocyte death. In this study, AMPKα2 knockout mice and the liver metastasis model of colon cancer cells were used to address the role of AMPKα isoforms in tumour inflammation. First, we found that the AMPKα2 deficiency exacerbated the liver injury and recruitment of macrophages. Meanwhile, although compensatory expression of AMPKα1 was not significant after AMPKα2 knockout, AMPKα1 phosphorylation was elevated in remnant liver in AMPKα2 knockout mice, which was positively associated with the enhanced energy deprivation in the AMPKα2 deficient mice. Furthermore, the activated AMPKα1 in macrophage contributed to its polarizing to tumour‐associated phenotype. Thus, the enhanced tumour‐associated inflammation and activation of AMPKα1 in the AMPKα2 deficient mice may exacerbate the tumour development by affecting the tumour inflammatory microenvironment. Our study suggests that the two isoforms of AMPKα, AMPKα1 and AMPKα2 play different roles in controlling tumour development.

Liver repair and regeneration after ischemia-reperfusion injury is associated with prolonged fibrosis.

Liver recovery after hepatic ischemia-reperfusion (I/R) injury is characterized by clearance of dead tissue and its replacement with functional liver parenchyma. Previous reports have observed fibrosis after liver I/R. To determine whether liver fibrosis after I/R was a pathologic consequence of the injury response, we assessed the development of liver fibrosis after I/R and its impact on subsequent insult. A murine model of partial I/R was used to induce liver injury and study the reparative response. During liver remodeling after I/R, expression of the profibrotic genes increased in the ischemic liver. Histologically, α-smooth muscle actin (α-SMA)-positive hepatic stellate cells (HSCs)/myofibroblasts increased, and collagen deposition was enhanced along the injured site. Selective staining experiments showed that HSCs, not portal fibroblasts, were the major source of myofibroblasts. During liver repair after I/R, liver fibrosis was readily observed at the interface between necrotic tissue and regenerating liver in association with HSCs/myofibroblasts. The number of HSCs/myofibroblasts decreasing shortly after the full resolution of necrotic injury and restoration are normal liver architecture. However, liver fibrosis persisted for several more weeks before gradually resolving. Resolution of liver fibrosis was accompanied by upregulated expression of matrix metalloproteinase-13. After resolution of fibrosis, the administration of CCl4 did not result in exacerbated liver injury, suggesting that I/R injury does not predispose the liver to future fibrotic insults. The data suggest that liver fibrosis is a component of tissue repair after I/R, is caused by myofibroblasts derived from HSC, and does not increase susceptibility of the liver to subsequent hepatic injury. NEW & NOTEWORTHY This study is the first to assess pathology of liver fibrosis during the reparative process after ischemia-reperfusion (I/R) injury. Here we show that profibrotic gene expression increased in the liver after I/R, and collagen accumulation produced by hepatic stellate cells (HSCs)/myofibroblasts enhanced at the interface between necrotic tissue and regenerating liver. Liver fibrosis gradually resolved concomitant with decreasing activation of HSC and upregulating matrix metalloproteinase-13. After resolution of fibrosis, the liver was not more susceptible to subsequent hepatic injury.

From the Editor’s desk....: November 2018

From the Editor’s desk....: November 2018

Effect of bone marrow mesenchymal stem cell transplantation on CCl₄-induced liver injury in rats and intervention effects of Yiguanjian

The aim of this paper was to observe the function of bone marrow mesenchymal stem cell (BMSC) transplantation in process of liver injury induced by carbon tetrachloride (CCl₄) in vivo and the intervention effect of Yiguanjian (YGJ), a compound of Chinese herbal medicine. Wistar rats were randomly divided into five groups: normal group, model group, cell transplantation (CT) group, YGJ group and cell transplantation plus Yiguanjian (CTY) group. Liver injury was induced through subcutaneous injection with CCl₄ at a dose of 3 mL·kg⁻¹ body weight for 4 weeks, twice a week. They were injected for a total of 9 times. After the first injection with CCl₄, rats in the CT group and CTY group were injected with the third-generation BMSCs at dose 1×10⁶ (suspended in 1 mL saline solution) via tail vein. Rats in the YGJ and CTY groups were also intragastrically administered with Yiguanjian once a day. Rat serum ALT and AST activities were increased significantly on the second day after injection with CCl₄, while BMSC transplantation and Yiguanjian decreased their activities. After 4 weeks of injection with CCl₄, serum ALT, AST and γ-GT activities, and serum TNF-α and IL-6 expressions were increased, while TBIL were decreased in model rats compared with normal rats. Meanwhile, liver cells edema, plasmatic loose, and numerous lipid droplets were observed in rats of the model group. BMSC transplantation aggravated liver injury compared with model rats, which was manifested by decreasing SOD activity, increased MDA, TG, TNF-α and IL-6 levels, and aggravated necrosis level of hepatocytes, fusion of lipid droplets, and collagen deposition in liver tissue. Yiguanjian decreased liver injury induced by CCl₄ alone and CCl₄ plus BMSC transplantation. SRY gene in situ hybridization method was used to detect the positive SRY expressions in heart, liver, spleen, lung and kidney, especially in liver, while Yiguangjian decreased liver SRY expression. Wnt and β-catenin showed high expressions in rats of normal group, which were decreased significantly in rats of models group, while Yiguanjian increased their expressions. In conclusion, BMSC transplantation could exacerbate liver injury, while Yiguanjian could protect liver injury induced by CCl₄ and BMSC transplantation, which was related to decreasing the homing of BMSCs to liver and up-regulating Wnt/β-catenin signaling pathway.

Galactomannan More than Pectin Exacerbates Liver Injury in Mice Fed with High-Fat, High-Cholesterol Diet.

Galactomannan and citrus pectin are considered 'super fibers' known for altering gut microbiota composition and improving glucose and lipid metabolism. The study aims to investigate the fiber's effect on a nonalcoholic steatohepatitis (NASH) model. Two feeding experiments are carried out using groups of 7-8 week-old male C57BL/6J mice. The diets used are based on a high cholesterol/cholate diet (HCD), such as a nutritional NASH model. Mice are fed a diet with or without 15% fiber-citrus pectin (HCD-CP) or galactomannan (HCD-G) together with the HCD (first experiment), which commenced 3 weeks prior to the HCD (second experiment). Liver damage is evaluated by histological and biochemical parameters. Galactomannan leads to lesser weight gain and improved glucose tolerance, but increased liver damage. This is shown by elevated levels of liver enzymes compared to that with HCD alone. Fibers induce higher steatosis, as evaluated by liver histology. This intriguing result is linked to various changes in the gut microbiota, such as elevated Proteobacteria levels in the galactomannan group, which are correlated with disturbed metabolism and dysbiosis. In a NASH mouse model, galactomannan increases liver damage but improves glucose metabolism. Changes in the microbiota composition may answer this enigmatic observation.

Gut inflammation exacerbates hepatic injury in the high-fat diet induced NAFLD mouse: Attention to the gut-vascular barrier dysfunction

AimsGut inflammation has been put forward to be associated with hepatic injury in the clinical practice. The dismantled intestinal barrier was highly concerned, however, largely unknown about the role of gut-vascular barrier (GVB) in this process. This study aimed to investigate if inflamed gut directly contributes to the progression of non-alcoholic steatohepatitis (NASH), especially attention to the GVB dysfunction. Main methodsMale C57bl/6 mice were fed with a high-fat diet (HFD) and 1% DSS for 12 weeks. The colonic inflammatory injury as well as hepatic injury were evaluated. The GVB function was assessed via measuring the permeability to fluorescently-labeled dextran (70 kDa) and the expression of plasmalemma vesicle-associated protein-1 (PV1). Furthermore, the plasma endotoxin level and hepatic TLR4/TLR9 mRNA expression were detected. Key findingsThere were evident colitis in DSS-exposed mice, which trend to be more apparent in HFD ones. The HFD + DSS mice exhibited more serious hepatic steatosis, inflammation and fibrosis than HFD groups. The downregulated tight junction protein in HFD + DSS mice indicated loss of epithelial barrier. The GVB disruption were also confirmed with increased permeability to macromolecules and high expression of endothelial PV1 in HFD + DSS mice. Accordingly, potentially elevated plasma endotoxin levels and markedly increased TLR4/TLR9 mRNA expression were demonstrated in HFD + DSS mice rather than HFD groups. SignificanceGut inflammation exacerbates liver injury and fibrosis in HFD mice, which may contribute to the development of NASH. Beyond the damaged intestinal epithelial barrier, GVB disruption with bacterial translocation into may play a key role in the pathogenesis of NASH.

Dynamic MTORC1-TFEB feedback signaling regulates hepatic autophagy, steatosis and liver injury in long-term nutrient oversupply

ABSTRACTNormal metabolism requires a controlled balance between anabolism and catabolism. It is not completely known how this balance can be retained when the level of nutrient supply changes in the long term. We found that in murine liver anabolism, as represented by the phosphorylation of RPS6KB (ribosomal protein S6 kinase), was soon elevated while catabolism, as represented by TFEB (transcription factor EB)-directed gene transcription and lysosomal activities, was downregulated after the administration of a high-fat diet (HFD). Surprisingly, neither the alteration in RPS6KB phosphorylation nor that in TFEB functions was static over the long course of HFD feeding. Instead, the 2 signals exhibited dynamic alterations in opposite directions, which could be explained by the dependence of MTORC1 (MTOR complex 1) activation on TFEB-supported lysosome function and the feedback suppression of TFEB by MTORC1. Disruption of the dynamics by enforced expression of TFEB in HFD-fed mice at the peaks of MTORC1 activation restored lysosome function. Consistently, interference of MTORC1 activation with rapamycin or with a constitutively activated RRAGA mutant at the peak or nadir of MTORC1 oscillation enhanced or reduced the lysosome function, respectively. These treatments also improved or exacerbated hepatic steatosis and liver injury, respectively. Finally, there was a significant inverse correlation between TFEB activation and steatosis severity in the livers of patients with non-alcohol fatty liver diseases, supporting the clinical relevance of TFEB-regulated events. Thus, maintaining catabolic function through feedback mechanisms during enhanced anabolism, which is caused by nutrient oversupply, is important for reducing liver pathology.

HMBOX1 in hepatocytes attenuates LPS/D-GalN-induced liver injury by inhibiting macrophage infiltration and activation

The HMBOX1 (Homeobox Containing 1) gene was first isolated from the human pancreatic cDNA libraries and is widely expressed in many tissues. Previously, we detected high expression of HMBOX1 in the liver, but its function was unclear. In this study, hepatocyte-specific HMBOX1 knockout mice (Hm△hep mice) were generated and used to characterize the function of HMBOX1 in the LPS/D-GalN-induced acute liver failure model. HMBOX1-knockout exhibits exacerbated liver injury induced by LPS/D-GalN, accompanied with high levels of inflammatory cytokines both in the liver and in circulation. Further investigation demonstrated that HMBOX1 negatively regulates NF-κB signal transduction. Therefore, HMBOX1-knockout in hepatocytes promotes CCL2 expression through the activation of NF-κB signaling, which enhanced the infiltration of macrophages into the liver. In addition, the decrease of HMBOX1 in hepatocytes promotes the activation of macrophages, upregulating CD80 and MHCⅡ, as well as inflammatory factors TNF-α and IL-6. Importantly, overexpression of HMBOX1 rescued liver injury in Hm△hep mice. These findings indicate that HMBOX1 in hepatocytes acts as a key immunosuppressive factor for inflammation and plays a critical protective role in LPS/D-GalN-induced liver injury.

Abnormal neutrophil traps and impaired efferocytosis contribute to liver injury and sepsis severity after binge alcohol use

Neutrophil extracellular traps (NETs) are an important strategy utilized by neutrophils to immobilize and kill invading microorganisms. Herein, we studied NET formation and the process of neutrophil cell death (NETosis), as well as the clearance of NETs by macrophages (MΦ) (efferocytosis) in acute sepsis following binge drinking. Healthy volunteers consumed 2 ml of vodka/kg body weight, before blood endotoxin and 16 s rDNA were measured. Peripheral neutrophils were isolated and exposed to alcohol followed by phorbol 12-myristate 13-acetate (PMA) stimulation. Mice were treated with three alcohol binges and intraperitoneal lipopolysaccharide (LPS) to assess the dynamics of NET formation and efferocytosis. In vivo, anti-Ly6G antibody (IA8) was used for neutrophil depletion. Inducers of NETs (endotoxin and bacterial DNA) significantly increased in the circulation after binge alcohol drinking in humans. Ex vivo, alcohol alone increased NET formation, but upon PMA stimulation alcohol attenuated NET formation. Binge alcohol in mice resulted in a biphasic response to LPS. Initially, binge alcohol reduced LPS-induced NET formation and resulted in a diffuse distribution of neutrophils in the liver compared to alcohol-naïve mice. Moreover, indicators of NET formation including citrullinated histone H3, neutrophil elastase, and neutrophil myeloperoxidase were decreased at an early time point after LPS challenge in mice receiving binge alcohol, suggesting decreased NET formation. However, in the efferocytosis phase (15 h after LPS) citrullinated histone-H3 was increased in the liver in alcohol binge mice, suggesting decreased clearance of NETs. In vitro alcohol treatment reduced efferocytosis and phagocytosis of NETotic neutrophils and promoted expression of CD206 on MΦ. Finally, depletion of neutrophils prior to binge alcohol ameliorated LPS-induced systemic inflammation and liver injury in mice. Dysfunctional NETosis and efferocytosis following binge drinking exacerbate liver injury associated with sepsis. Disease severity in alcoholic liver disease (ALD) is associated with a significant presence of neutrophils (a type of immune cell) in the liver. It remains unknown how alcohol affects the capacity of neutrophils to control infection, a major hallmark of ALD. We found that binge alcohol drinking impaired important strategies used by neutrophils to contain and resolve infection, resulting in increased liver injury during ALD.

DEP domain-containing mTOR-interacting protein suppresses lipogenesis and ameliorates hepatic steatosis and acute-on-chronic liver injury in alcoholic liver disease.

The dysregulation of SIRT1-DEPTOR-mTORC1 signaling is a critical determinant of ALD pathology; targeting SIRT1 and DEPTOR and selectively inhibiting mTORC1-S6K1 signaling may have therapeutic potential for treating ALD in humans. (Hepatology 2018).

Exacerbated liver injury of antithyroid drugs in endotoxin-treated mice

Drug-induced liver injury is a major concern in clinical studies as well as in post-marketing surveillance. Previous evidence suggested that drug exposure during periods of inflammation could increase an individual’s susceptibility to drug hepatoxicity. The antithyroid drugs, methimazole (MMI) and propylthiouracil (PTU) can cause adverse reactions in patients, with liver as a usual target. We tested the hypothesis that MMI and PTU could be rendered hepatotoxic in animals undergoing a modest inflammation. Mice were treated with a nonhepatotoxic dose of LPS (100 µg/kg, i.p) or its vehicle. Nonhepatotoxic doses of MMI (10, 25 and 50 mg/kg, oral) and PTU (10, 25 and 50 mg/kg, oral) were administered two hours after LPS treatment. It was found that liver injury was evident only in animals received both drug and LPS, as estimated by increases in serum alanine aminotransferase (ALT), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), and TNF-α. An increase in liver myeloperoxidase (MPO) enzyme activity and tissue lipid peroxidation (LPO) in addition of liver glutathione (GSH) depletion were also detected in LPS and antithyroid drugs cotreated animals. Furthermore, histopathological changes including, endotheliitis, fatty changes, severe inflammatory cells infiltration (hepatitis) and sinusoidal congestion were detected in liver tissue. Methyl palmitate (2 g/kg, i.v, 44 hours before LPS), as a macrophage suppressor, significantly alleviated antithyroids hepatotoxicity in LPS-treated animals. The results indicate a synergistic liver injury from antithyroid drugs and bacterial lipopolysaccharide coexposure.

Vitamin A deficiency provokes aberrant T cell responses and exacerbates liver injury in LCMV-infected mice

Abstract Vitamin A deficiency (VAD) is a public health problem worldwide; however, its role and underlying mechanisms in viral infection are not entirely understood. In this study, we detected elevated LCMV-specific T cell responses in VAD mice at the acute stage (7 dpi). These VAD mice exhibited higher serum ALT levels and increased liver permeability. Consistently, enhanced antiviral T cell responses were observed in VAD mice in persistent infection (30 dpi), as evidenced by decreased PD-1 expression and increased cytokine production. To investigate whether VAD causes an intrinsic abnormality of T cells during animal development and growth, we transferred spleen cells from control and VAD mice into CD45.1 recipient mice, followed by LCMV infection, and found that antiviral T cell responses were comparable between control and VAD donor cells. However, when CD45.1 cells were transferred into control and VAD recipient mice, they showed a highly activated phenotype in VAD mice. These results suggest that vitamin A or its metabolites restrict T cell activation through an extrinsic way. Retinoic acid (RA) is considered one of the important metabolites of vitamin A. We found that RA administration inhibited excessive T cell responses in VAD mice. To dissect the mechanism of RA, we treated splenocytes and purified CD8+ T cells with RA, followed by PMA stimulation. RA treatment reduced the phosphorylation of AKT, p38, ERK, and S6, as well as the abundance of transcriptional factor NFATc1. Together, our study demonstrated that VAD caused an aberrant T cell response to viral infection, and RA may have the potential to serve as a therapeutic agent for excessive immune responses and tissue injury in VAD patients.

Cultivation of Hepatic Stellate Cells in 3D ECM to Simulate Physiological and Fibrotic Conditions

BackgroundHepatic stellate cells, the major providers of hepatic retinoids and extracellular matrix (ECM), reside in the space of Disse filled with loose basement like ECM, and flanked by hepatocytes and sinusoidal endothelial cells. Upon hepatic injury, stellate cells are activated to express multiple matrix metalloproteinases (MMPs) and to mobilize retinoids for wound healing. In chronic injury, the quiescent stellate cells undergo trans‐differentiation into myofibroblast like cells, marked by loss of retinoids, expression interstitial ECM as well as smooth muscle actin (alpha‐SMA), and gain of contractibility. Although knowledge has been evolved substantially, two fundamental questions remain largely unknown as to how, in normal liver, HSCs maintain quiescence, and how, by injury, HSCs are activated within the ECM milieu.ResultsTo recapitulate the sub‐sinusoid microenvironment we embedded rat primary stellate cells in three‐dimensional ECM (3D ECM). Cultured on plastic, the stellate cells activated spontaneously, showing loss of vitamin A droplets and expression of alpha‐SMA. However, in 3D Matrigel, stellate cells retained retinoid droplets, in association with elevated level of lecithin retinoid acyltransferase (LRAT), a key enzyme for retinol esterification. In 3D ECM, stellate cells were arrested at G0/G1 phase, while on plastic the cells underwent cell cycling and stopped at G2/M phase. We then reconstituted the microenvironment of sinusoids by introducing Kupffer cells, the major hepatic inflammatory cells, into 3D ECM with HSCs. Activated Kupffer cells triggered subsequent activation of stellate cells, evidenced by expression of multiple MMPs, buildup of stress fibers, and loss of retinoids. The Kupffer cell‐mediated activation of stellate cells was blocked by interleukin‐1 receptor antagonist, demonstrating interleukin‐1 as a major injury signal from Kupffer cells conducting stellate cell activation and trans‐differentiation. Furthermore, within 3D ECM, but not on the plastic, interleukin‐1 signal was greatly amplified by stellate cells in an autocrine manner, which may exacerbate liver injury by expressing MMPs in the space of Disse. The myofibroblastic cells derived from the 3D ECM culture were contractile in response to endothelin.ConclusionThe 3D ECM culture provides a model to simulate key physiological functions of stellate cells in normal liver, and also to recapitulate patho‐physiological responses in liver injury. The method may also be used in cell‐based drug screening to identify components targeting liver failure and fibrosis.Support or Funding InformationNational Institutes of Health (NIH) Grants R01s, DK069418‐05 and AR051558, and the Natural Science Foundation of ChinaThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Protein S Exacerbates Chronic Liver Injury and Fibrosis

Protein S is a vitamin K-dependent glycoprotein produced mainly in the liver with anticoagulant, anti-inflammatory, immune-modulatory, and antiapoptotic properties. Protein S exacerbates acute liver injury by prolonging the survival of liver immune cells. However, the effect of protein S on chronic liver injury and fibrosis is unknown. Here, we investigated whether human protein S can affect chronic liver injury and fibrosis. Liver injury/fibrosis was induced by carbon tetrachloride injection in mice overexpressing human protein S and in wild-type mice. Human protein S transgenic mice receiving carbon tetrachloride showed significantly higher circulating levels of liver transaminases, increased liver expression of inflammatory cytokines, significantly more extended liver fibrosis, and areas with DNA breakage after chronic injury compared with wild-type mice. Wild-type mice infused with exogenous human protein S exhibited exacerbated liver injury and increased number of hepatic stellate cells compared with untreated mice. Human protein S inhibited apoptosis and increased Akt pathway activation in hepatic stellate cells. The antiapoptotic activity of protein S may play a role in chronic liver injury and subsequent liver fibrosis.

IL-33 induces immunosuppressive neutrophils via a type 2 innate lymphoid cell/IL-13/STAT6 axis and protects the liver against injury in LCMV infection-induced viral hepatitis.

Viral hepatitis is still a public health problem affecting several million people around the world. Neutrophils are polymorphonuclear cells that have a critical role in antibacterial infection. However, the role of neutrophils in viral infection is not fully understood. By using a mouse model of lymphocytic choriomeningitis virus infection-induced viral hepatitis, we observed increased neutrophil recruitment in the liver accompanied by enhanced CD8+ T-cell responses. Liver neutrophils expressed high levels of immunomodulatory cytokines, such as C-X-C chemokine ligand 2, arginase-1, inducible nitric oxide synthase and interleukin (IL)-10, demonstrating immunosuppressive properties. Depletion of neutrophils in vivo by a neutralizing antibody resulted in the exacerbation of liver injury and the promotion of T-cell responses at the immune contraction stage. IL-33 significantly induced neutrophil recruitment in the liver and attenuated liver injury by limiting effector T-cell accumulation. Mechanistically, we found that IL-33 promoted the expression of arginase-1 in neutrophils through the type 2 innate lymphoid cell (ILC2)-derived IL-13. Additionally, IL-13 increased the inhibitory effect of neutrophils on CD8+ T-cell proliferation in vitro, partially through arginase-1. Finally, we found that IL-13 induced arginase-1 expression, depending on signal transducer and activator of transcription factor 6 (STAT6) signaling. Therefore, IL-33 induced immunosuppressive neutrophils via an ILC2/IL-13/STAT6 axis. Collectively, our findings shed new light on the mechanisms associated with IL-33-triggered neutrophils in the liver and suggest potential targets for therapeutic investigation in viral hepatitis.

FGF 21 deficiency slows gastric emptying and reduces initial blood alcohol concentration in mice exposed to acute alcohol in fasting state

Excess alcohol consumption can lead to alcoholic liver disease. Fibroblast growth factor 21 (FGF21) is a metabolic regulator with multiple physiologic functions. Previous study demonstrated that FGF21 deficiency exacerbated alcohol-induced liver injury and exogenous FGF21 administration protected liver from chronic alcohol-induced injury. In this study, we aimed to explore the role of FGF21 in alcohol metabolism in mice. FGF21 knockout (KO) mice and the wild type(WT) control mice were divided into two groups and fasted for 24 h followed by a bonus of alcohol treatment at a dose of 5 g/kg body weight via gavage. Serum alcohol concentration was measured after gavage at 0.5, 2, 3, 4 and 6 h, respectively. At the end, gastric and liver tissues were collected. Serum alcohol concentration of KO mice was significantly lower than that of WT at 0.5 h after alcohol expose. There were no significant differences in alcohol dehydrogenase (ADH) activity and aldehyde dehydrogenase 2 (ALDH2) activity in gastric and liver tissues between WT and the KO mice. However, gastric emptying time of KO mice was much longer than that of WT mice. In addition, the intestinal permeability and serum GLP-1 level of KO mice were significantly higher than that of WT mice. These results suggest that FGF21 deficiency slow gastric emptying rate and indirectly influence initial alcohol metabolism in mice exposed to acute alcohol. Our findings provide additional information for understanding the gastrointestinal mechanism of alcoholic liver disease and other alcohol use disorders.

New 14-mm diameter Niti-S biliary uncovered metal stent for unresectable distal biliary malignant obstruction.

AIMTo investigate whether an uncovered self-expandable metal stent (UCSEMS) with a large diameter could prevent recurrent biliary obstruction (RBO).METHODSThirty-eight patients with malignant biliary obstruction underwent treatment with an UCSEMS with a 14-mm diameter (Niti-S 14). Retrospectively, we evaluated technical and functional success rate, RBO rate, time to RBO, survival time, and adverse events in these patients.RESULTSStent placement success and functional success were achieved in all patients. Two patients (5.3%) had RBO due to tumor ingrowth or overgrowth. The median time to RBO was 190 (range, 164-215) d. The median survival time was 120 (range, 18-502) d. The 6-mo non-RBO rate was 91%. Other adverse events other than RBO occurred as follows: Acute cholecystitis, post-ERCP pancreatitis, hemobilia, and fever without exacerbation of liver injury, and liver abscess in 4 (10.3%), 3 (7.9%), 2 (5.3%), 1 (2.6%), and 1 (2.6%), respectively. Migration of the stents was not observed.CONCLUSIONNiti-S 14 is considered to be a preferable metal stent because of a low rate of RBO with no migration.

Spred2 Deficiency Exacerbates D-Galactosamine/Lipopolysaccharide -induced Acute Liver Injury in Mice via Increased Production of TNF\u03b1

Acute liver injury (ALI) is characterized by hepatocyte damage and inflammation. In the present study, we examined whether the absence of Sprouty-related EVH1-domain-containing protein 2 (Spred2), a negative regulator of the Ras/Raf/ERK/MAPK pathway, influences ALI induced by D-galactosamine (D-GalN) and lipopolysaccharide (LPS). Compared to wild-type mice, Spred2−/− mice developed exacerbated liver injury represented by enhanced hepatocyte damage and inflammation. Enhanced ERK activation was observed in Spred2−/−-livers, and the MEK/ERK inhibitor U0126 ameliorated ALI. Hepatic tumour necrosis factor α (TNFα) and interleukin (IL)-1β levels were increased in Spred-2−/−-livers, and the neutralization of TNFα dramatically ameliorated ALI, which was associated with decreased levels of endogenous TNFα and IL-1β. When mice were challenged with D-GalN and TNFα, much severer ALI was observed in Spred2−/− mice with significant increases in endogenous TNFα and IL-1β in the livers. Immunohistochemically, Kupffer cells were found to produce TNFα, and isolated Kupffer cells from Spred2−/− mice produced significantly higher levels of TNFα than those from wild-type mice after LPS stimulation, which was significantly decreased by U0126. These results suggest that Spred2 negatively regulates D-GalN/LPS-induced ALI under the control of TNFα in Kupffer cells. Spred2 may present a therapeutic target for the treatment of ALI.

Myeloid deficiency of CCN3 exacerbates liver injury in a mouse model of nonalcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is a condition in which fat accumulates in the liver of patients without a prior history of alcohol abuse. The most severe form, nonalcoholic steatohepatitis (NASH), often leads to hepatic fibrosis and cirrhosis with ensuing complications. To date, there is no pharmacologic treatment for NASH. The biological effects of CCN3, specifically its role in the regulation of inflammation, reactive oxygen species production and angiogenesis, have been recently established. Additional data suggests that CCN3 is associated with the development of tumors in the liver yet may be protective of liver fibrogenesis. Currently, the role of CCN3 in NAFLD/NASH remains unexplored. Therefore, the objective of our investigation was to decipher the role of myeloid-deficient CCN3 in the pathogenesis of NASH and the underlying mechanisms of CCN3 in modulation of hepatic function. Wild type and myeloid CCN3-deficient mice were fed a methionine- and choline-deficient diet to induced NASH. Increased lipid, cholesterol, and cholesterol ester accumulation was observed in myeloid CCN3-deficient mice when compared to the control group. This disease state was associated with alterations of key genes involved in lipid synthesis, β-oxidation and lipid uptake. Additionally, the levels of important molecules critical for inflammation, ROS generation, ER stress and liver injury were significantly elevated; as was the observed severity of hepatic apoptosis and necroptosis. Therefore, CCN3 is critical for protection from hepatic apoptosis and necroptosis in our induced NASH model and our findings suggest that CCN3 can be exploited as a therapeutic target for the treatment of NASH.

Metabolic adaptation to intermittent fasting is independent of peroxisome proliferator-activated receptor alpha

BackgroundPeroxisome proliferator-activated receptor alpha (PPARA) is a major regulator of fatty acid oxidation and severe hepatic steatosis occurs during acute fasting in Ppara-null mice. Thus, PPARA is considered an important mediator of the fasting response; however, its role in other fasting regiments such as every-other-day fasting (EODF) has not been investigated. MethodsMice were pre-conditioned using either a diet containing the potent PPARA agonist Wy-14643 or an EODF regimen prior to acute fasting. Ppara-null mice were used to assess the contribution of PPARA activation during the metabolic response to EODF. Livers were collected for histological, biochemical, qRT-PCR, and Western blot analysis. ResultsAcute fasting activated PPARA and led to steatosis, whereas EODF protected against fasting-induced hepatic steatosis without affecting PPARA signaling. In contrast, pretreatment with Wy-14,643 did activate PPARA signaling but did not ameliorate acute fasting-induced steatosis and unexpectedly promoted liver injury. Ppara ablation exacerbated acute fasting-induced hypoglycemia, hepatic steatosis, and liver injury in mice, whereas these detrimental effects were absent in response to EODF, which promoted PPARA-independent fatty acid metabolism and normalized serum lipids. ConclusionsThese findings indicate that PPARA activation prior to acute fasting cannot ameliorate fasting-induced hepatic steatosis, whereas EODF induced metabolic adaptations to protect against fasting-induced steatosis without altering PPARA signaling. Therefore, PPARA activation does not mediate the metabolic adaptation to fasting, at least in preventing acute fasting-induced steatosis.