Osthole ameliorates hepatic fibrosis and inhibits hepatic stellate cell activation.

BACKGROUND: Hepatic fibrosis is a dynamic process which ultimately leads to cirrhosis in almost patients with chronic hepatic injury. However, progressive fibrosis is a reversible scarring response. Activation of hepatic stellate cells (HSCs) is the prevailing process during hepatic fibrosis. Osthole is an active component majorly contained in the fruit of Cnidium monnieri (L.) Cusson. This present study investigated the therapeutic effects of osthole on rat liver fibrosis and HSC activation. RESULTS: We established the thioacetamide (TAA)-model of Sprague-Dawley (SD) rats to induce hepatic fibrosis. Rats were divided into three groups: control, TAA, and TAA + osthole (10 mg/kg). In vivo, osthole significantly reduced liver injury by diminishing levels of plasma AST and ALT, improving histological architecture, decreasing collagen and α-SMA accumulation, and improving hepatic fibrosis scores. Additionally, osthole reduced the expression of fibrosis-related genes significantly. Osthole also suppressed the production of fibrosis-related cytokines and chemokines. Moreover, nuclear translocation of p65 was significantly suppressed in osthole-treated liver. Osthole also ameliorated TAA-induced injury through reducing cellular oxidation. Osthole showed inhibitory effects in inflammation-related genes and chemokines production as well. In vitro, we assessed osthole effects in activated HSCs (HSC-T6 and LX-2). Osthole attenuated TGF-ß1-induced migration and invasion in HSCs. Furthermore, osthole decreased TNF-α-triggered NF-κB activities significantly. Besides, osthole alleviated TGF-ß1- or ET-1-induced HSCs contractility. CONCLUSIONS: Our study demonstrated that osthole improved TAA-caused liver injury, fibrogenesis and inflammation in rats. In addition, osthole suppressed HSCs activation in vitro significantly.

Fluvastatin attenuates hepatic steatosis-induced fibrogenesis in rats through inhibiting paracrine effect of hepatocyte on hepatic stellate cells.

BACKGROUND: Non-alcoholic steatohepatitis (NASH) is associated with hepatic fibrogenesis. Despite well-known cholesterol-lowering action of statins, their mechanisms against NASH-mediated fibrogenesis remain unclear. This study aimed at investigating the in vitro and in vivo anti-fibrotic properties of fluvastatin (Flu). METHODS: Palmitate (PA)-induced changes in intracellular hydrogen peroxide levels in primary rat hepatocytes (PRHs) and human hepatoma cell line (HepG2) were quantified by dichlorofluorescein diacetate (DCF-DA) dye assay, whereas changes in expressions of NADPH oxidase gp91 (phox) subunit, α-smooth muscle actin (α-SMA), and NFκB p65 nuclear translocation were quantified with Western blotting. Quantitative real-time polymerase chain reaction (q-PCR) was used to investigate mRNA expressions of pro-inflammatory genes (ICAM-1, IL-6, TNF-α). Conditioned medium (CM) from PA-treated PRHs was applied to cultured rat hepatic stellate cell line, HSC-T6, with or without Flu-pretreatment for 2 h. Pro-fibrogenic gene expressions (COL1, TIMP-1, TGF-ß1, α-SMA) and protein expression of α-SMA were analyzed. In vivo study using choline-deficient L-amino acid defined (CDAA) diet-induced rat NASH model was performed by randomly assigning Wistar rats (n = 28) to normal controls (n = 4), CDAA diet with vehicles, and CDAA diet with Flu (5 mg/kg or 10 mg/kg) (n = 8 each) through gavage for 4 or 8 weeks. Livers were harvested for histological, Western blot (α-SMA), and q-PCR analyses for expressions of pro-inflammatory (IL-6, iNOS, ICAM-1) and pro-fibrogenic (Col1, α-SMA, TIMP-1) genes. RESULTS: In vitro, Flu (1-20 µM) inhibited PA-induced free-radical production, gp91 (phox) expression, and NFκB p65 translocation in HepG2 and PRHs, while CM-induced α-SMA protein expression and pro-fibrogenic gene expressions in HSC-T6 were suppressed in Flu-pretreated cells compared to those without pretreatment. Moreover, α-SMA protein expression was significantly decreased in HSC-T6 cultured with CM from PA-Flu-treated PRHs compared to those cultured with CM from PA-treated PRHs. Flu also reduced steatosis and fibrosis scores, α-SMA protein expression, mRNA expression of pro-inflammatory and pro-fibrogenic genes in livers of CDAA rats. CONCLUSIONS: We demonstrated PA-induced HSC activation through paracrine effect of hepatocyte in vitro that was significantly suppressed by pre-treating HSC with Flu. In vivo, Flu alleviated steatosis-induced HSC activation and hepatic fibrogenesis through mitigating inflammation and oxidative stress, suggesting possible therapeutic role of Flu against NASH.

Involvement of the HIF-1α and Wnt/ß-catenin pathways in the protective effects of losartan on fatty liver graft with ischaemia/reperfusion injury.

Besides cardioprotective effects, the AT1R (angiotensin-II type 1 receptor) antagonist losartan protects the liver from IRI [IR (ischaemia/reperfusion) injury], but the mechanism has not been fully determined. The HIF (hypoxia inducible factor)-1α and Wnt/ß-catenin signalling pathways have been reported to be involved in the mechanism of liver IRI. Therefore the aim of the present study was to determine whether the Wnt/HIF axis is part of the mechanism of the positive effect of AngII inhibition by losartan in liver IRI in rats. Various measurements were made in MCD/HF-NASH (methionine- and choline-deficient-diet/high-fat-diet-induced non-alcoholic steatohepatitis) rats with liver IRI. Acute losartan pre-administration markedly reversed the IR-suppressed levels of the hepatic-protective factors IL (interleukin)-6, IFN (interferon)-γ, Wnt3a, ß-catenin and HIF-1α, and decreased hepatic blood flow and IR-elevated serum ALT (alanine aminotransferase), hepatic TNF (tumour necrosis factor)-α, IL-1α, hepatic congestion, vacuolization and necrosis, hepatic Suzuki IRI scores, necrotic index and levels of TBARS (thiobarbituric acid-reacting substances) in MCD/HF-NASH rats. Furthermore, acute Wnt3a pre-treatment significantly inhibited IR-elevated serum ALT, hepatic Suzuki IRI scores and TBARS, and restored the IR-depleted ß-catenin/HIF-1α activity in MCD/HF-NASH rats. Simultaneous acute sFRP2 (secreted frizzled-related protein 2; a Wnt3a inhibitor) pre-treatment eliminated the losartan-related beneficial effects in MCD/HF-NASH rats with liver IRI, which was accompanied by a decrease in hepatic HIF-1α/ß-catenin activity. Losartan-induced up-regulation of HIF-1α and Wnt/ß-catenin signalling was associated with the recovery of IR-inhibited hepatic Bcl-2, Mn-SOD (manganese superoxide), Cu/Zn-SOD (copper/zinc superoxide) and GSH levels, and the suppression of IR-increased hepatic catalase and caspase 3/caspase 8 levels in MCD/HF-NASH rats. In conclusion, up-regulation of the HIF-1α and Wnt/ß-catenin signalling pathways are part of the mechanism of the positive effects of losartan-related AngII inhibition in MCD/HF-NASH rats with liver IRI. Our study highlights the potential of the dual-organ protective agent losartan in NASH patients with steatotic livers and cardiovascular risk.

Anti-VEGFR agents ameliorate hepatic venous dysregulation/microcirculatory dysfunction, splanchnic venous pooling and ascites of NASH-cirrhotic rat.

BACKGROUND & AIMS: Antivascular endothelial growth factor receptor (VEGFR) agents improve hepatic fibrosis and portal hypertension in cirrhosis. Detail interactions among recruited/activated leucocytes, hepatic angiogenesis and fibrogenesis, splanchnic blood pooling, decreased hepatic veins to fluctuated splanchnic blood volume (hepatic venous dysregulation), portal hypertensive syndrome and ascites have never explored in cirrhosis. Our study used two anti-VEGFR agents - brivanib and sorafenib - to elucidate the relationship between above abnormalities of nonalcoholic steatohepatitis (NASH)-cirrhotic rats. MATERIALS AND METHODS: NASH-cirrhotic rats received 2-week brivanib, sorafenib or vehicle (NASH-cirrhotic+briv, NASH-cirrhotic+soraf and NASH-cirrhotic rats) were included for various measurements. RESULTS: In comparison with NASH-cirrhotic rats, significant decreased plasma VEGF, fibroblast growth factor, platelet-derived growth factor, hepatic tumour necrosis factor (TNFα), IL-1ß, IL-6, IL-17 were accompanied by decreased leucocyte mass/activity ((99 m) Tc-phytate and (18) F-FDG SPECT/PET/CT scans), hepatic leucocytes recruitment/microvascular density (fluorescence-enhanced intravital microscopy) and hydroxyproline content, and increased hepatic blood flow in NASH-cirrhotic+briv and NASH-cirrhotic+soraf rats. In addition, increased hepatic microvasculatures compliance-related improved buffering effect of portal vein to acute mannitol infusion was associated with decreased circulating nitric oxide and aldosterone, plasma volume expansion (dye dilution method), splanchnic blood pooling ((99 m) Tc-RBC SPECT/PET/CT scans), peripheral hypotension, portal hypertension and ascites in brivanib and sorafenib-treated NASH-cirrhotic rats. CONCLUSION: Besides antifibrotic, antiangiogenic and portal hypertensive effects, chronic antagonism of anti-VEGFR with brivanib and sorafenib improves hepatic blood flow, hepatic venous dysregulation, inhibits leucocytes recruitment/activation, splanchnic blood pooling and ascites formation in NASH-cirrhotic rats. Thus, brivanib and sorafenib might be ideal therapeutic agents in cirrhotic patients suffering from severe haemodynamic disarrangement and ascites.

Beneficial effects of dual vascular endothelial growth factor receptor/fibroblast growth factor receptor inhibitor brivanib alaninate in cirrhotic portal hypertensive rats.

BACKGROUND AND AIM: Vascular endothelial (VEGF) and fibroblast growth factor (FGF)-induced hepatic stellate (HSCs) and liver endothelial cells (LECs) activation accelerates hepatic fibrogenesis and angiogenesis, and hemodynamic dysarrangements in cirrhosis. VEGF targeting agents had been reported as potential drugs for cirrhosis. However, the evaluation of effects of dual VEGF/FGF targeting agent in cirrhosis is still limited. METHODS: Using hemodynamic parameters, blood chemistry, primary isolated HSCs and LECs, histology, and digital imaging, we assess the effects of 2-week brivanib alaninate, a dual VEGFR/FGFR inhibitor, treatment in the pathophysiology of bile duct-ligated-cirrhotic rats. RESULTS: Fibrogenic and angiogenic markers in the serum and liver of bile duct-ligated-cirrhotic rats, including hydroxyproline, transforming growth factor-ß1, angiopoietin-1, VEGF, FGF-2, endocan and phosphorylated-VEGFR2/VEGFR2, and phosphorylated-FGFR/FGFR together with hepatic CD31/angiopoietin-1 expressions (immunohistochemistry staining), angiogenesis (micro-computed tomography scan), microcirculatory dysfunction (in vivo miscroscopy and in situ liver perfusion study), portal hypertension, and hyperdynamic circulations (colored microsphere methods) were markedly suppressed and ameliorated by brivanib alaninate treatment. In in vitro study, acute brivanib alaninate incubation inhibited the transforming growth factor-ß1-induced HSCs contraction/migration and VEGF-induced LECs angiogenesis. Concomitantly, the overexpression of various fibrogenic and angiogenic markers in HSCs and LECs, and in their culture media, was increased in parallel and these changes were suppressed by acute brivanib alaninate incubation. CONCLUSIONS: This study demonstrated that brivanib alaninate targeting multiple mechanisms and working in the different pathogenic steps of the complications of cirrhotic rats with portal hypertension.

Rutin, a flavonoid and principal component of saussurea involucrata, attenuates physical fatigue in a forced swimming mouse model.

This study investigated the antifatigue effects of rutin, a flavonoid extracted from the ethyl acetate extract of S. involucrata. Mice were subjected to a weight-loaded forced swim test (WFST) on alternate days for 3 wk. Rutin was administered orally to the mice for 7 days in dosages of 15, 30, and 60 mg/kg body weight, and several biomarkers of physical fatigue were evaluated: swimming time, change in body weight, lipid peroxidation, lactic acid (LA), glycogen, and the activities of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx). On Day 7, the rutin-treated mice had a 3-fold longer exhaustive swimming time than the control mice, as well as significantly reduced blood LA concentrations. The 15, 30, and 60 mg/kg body weight rutin-supplemented groups displayed 11.2%, 22.5%, and 37.7% reduced malondialdehyde (MDA) concentrations, respectively, in brain and muscle tissues compared with the control exercised group. Our results indicated that the administration of rutin protected the mice against the depletion of SOD and GPx activities significantly. Following 7 days of rutin treatment, we sacrificed the mice and analyzed their soleus muscle and brain for peroxisome proliferator-activated receptor-α coactivator (PGC-1α) and sirtuin 1 (SIRT1) mRNA expression. We observed that rutin treatment increased PGC-1α and SIRT1 mRNA and protein expression. The changes in these markers of mitochondrial biogenesis were associated with increased maximal endurance capacity. The application of 2D gel electrophoresis to analyze the rutin-responsive protein profiles in the WFST mouse brain further revealed the upregulation of the CB1 cannabinoid receptor-interacting protein 1, myelin basic protein, Rho GDP dissociation inhibitor (GDI) alpha, and TPI, indicating that rutin might inhibit anxiety through the upregulation of the expression of anxiety-associated proteins. Western blot analysis of MAPK expression further confirmed the antianxiety effects of rutin. Our study results thus indicate that rutin treatment ameliorates the various impairments associated with physical fatigue.

Hepatitis C virus core protein stimulates fibrogenesis in hepatic stellate cells involving the obese receptor.

Hepatitis C virus core protein (HCVcp), which is secreted by infected cells, is reported as an immunomodulator in immune cells. However, the effects of HCVcp on hepatic stellate cells (HSCs), the key cells in liver fibrosis, still remain unclear. In this study, we investigated the effects of HCVcp on obese receptor (ObR) related downstream signaling pathways and fibrogenic gene expression in HSCs. LX-2, a human HSC line, was incubated with HCVcp. Inhibitors and short interfering RNAs were used to interrogate the mechanisms of HCVcp action on HSCs. HCVcp (20-100 ng/ml) concentration-dependently stimulated α-smooth muscle actin (α-SMA) protein expression and mRNA expression of α-SMA, procollagen α2(I) and TGF-ß1 genes, with a plateau of 220% of controls at 100 ng/ml. HCVcp induced mRNA and protein expression of ObR. Blocking of Ob-Rb with a neutralizing antibody inhibited phosphorylation of signal transducer and activator of transcription 3 (STAT3) and AMPKα stimulated by HCVcp. Furthermore, knockdown of Ob-Rb down-regulated HCVcp-induced STAT3, AKT, and AMPKα phosphorylation, and reversed HCVcp-suppressed mRNA expression of matrix metalloproteinase (MMP)-1, peroxisome proliferator-activated receptor (PPAR)γ and sterol regulatory element binding protein-1c (SREBP-1c) genes. AMPKα signaling blockade reversed HCVcp-suppressed SREBP-1c mRNA expression. HCVcp stimulated reactive oxygen species formation and gp91(phox) (a component of NADPH oxidase) protein expression, together with AKT phosphorylation, leading to suppression of PPARγ and SREBP-1c genes. Our results provide a new finding that HCVcp induced ObR-dependent Janus Kinase (JAK) 2-STAT3, AMPKα, and AKT signaling pathways and modulated downstream fibrogenetic gene expression in HSCs.

Hepatic endothelin-1 and endocannabinoids-dependent effects of hyperleptinemia in nonalcoholic steatohepatitis-cirrhotic rats.

UNLABELLED: Leptin, the ob gene product, is a protein released from adipocytes and has been detected in fibrotic and cirrhotic livers. Leptin in brain has an inhibitory effect on food intake. Nonalcoholic steatohepatitis (NASH) is characterized by hyperleptinemia. This study explores the possible mechanisms of hyperleptinemia in relation to increased intrahepatic resistance (IHR) and portal hypertension in NASH cirrhotic rats. NASH cirrhotic rats with hyperleptinemia were induced in Zucker (fa/fa) and lean rats by feeding the animals a high fat/methionine-choline-deficient (HF/MCD) diet with and without exogenous administration of recombinant leptin. Portal venous pressure (PVP), IHR, plasma and hepatic levels of various substances, histopathology of the liver, the hepatic hydroxyproline content, and the expression of various hepatic protein and messenger RNA (mRNA) were measured. Hepatic microcirculatory dysfunction and the vasoconstrictive response to endothelin-1 were also observed using a liver perfusion system and intravital microscopy. Finally, the effect of leptin on hepatic stellate cells (HSCs) was evaluated. Both in HF/MCD-Zucker and HF/MCD+leptin lean rats, significant hepatic fibrogenesis and cirrhosis, marked portal hypertension, microcirculatory dysfunction, an enhanced vasoconstrictive response to endothelin-1, and an increased IHR were found to be associated with higher levels of hepatic endothelin-1 and endocannabinoids, expression levels of the cannabinoid type 1 receptor, endothelin-1 type A receptor (ET(A) R), activator protein-1, transforming growth factor beta (TGF-ß)(1), osteopontin, tumor necrosis factor alpha (TNF-α), leptin, and the leptin receptor (OBRb). Interestingly, acute incubation of leptin directly increases the expression of ET(A) R, OBRb and activator protein-1 in HSCs. CONCLUSION: An HF/MCD diet and hyperleptinemia increase hepatic endocannabinoids production, promote hepatic fibrogenesis, enhance the hepatic vasoconstrictive response to endothelin-1, and aggravate hepatic microcirculatory dysfunction; these events subsequently increase IHR and portal hypertension in NASH cirrhotic rats.

Rho-kinase-dependent pathway mediates the hepatoprotective effects of sorafenib against ischemia/reperfusion liver injury in rats with nonalcoholic steatohepatitis.

During liver transplantation, nonalcoholic steatohepatitis (NASH) aggravates ischemia/reperfusion (IR) injury by activating various kinases and subsequently releasing cytokines and chemokines. Nonetheless, the effect of the multikinase inhibitor sorafenib on IR liver injury in rats with NASH has never been explored. Our study was designed to determine this effect and associated mechanisms in NASH rats. Sorafenib was acutely administered to NASH rats with IR liver injury that were or were not chronically pretreated with the Rho-kinase-specific inhibitor fasudil. Then, the following were evaluated: mean arterial pressure; hepatic blood flow and microcirculatory dysfunction; hepatic inflammation (serum alanine aminotransferase); necrosis; apoptosis; leukocyte infiltration; CD45 staining; caspase levels and DNA fragmentation; various serum and hepatic cytokines; and proteins and genes of the Raf/mitogen-activated protein-extracellular signal-regulated kinase kinase (MEK)/extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase, and apoptosis pathways. In NASH rats with IR liver injury, hepatic inflammation, necrosis, apoptosis, leukocyte infiltration, and microcirculatory dysfunction were significantly attenuated by the acute administration of sorafenib through the inhibition of the hepatic release of macrophage inflammatory protein 2, keratinocyte chemoattractant, granulocyte-monocyte colony-stimulating factor, and hepatic caspase-3 and caspase-9 as well as DNA fragmentation. Furthermore, there was decreased expression of p-Raf1 (where p indicates the phosphorylated form), p-MEK1/2, p-ERK1/2, p-Rho-kinase, B cell lymphoma 2-associated death promoter, and B cell lymphoma 2-associated X protein at the protein and messenger RNA levels. Notably, the aforementioned beneficial effects of sorafenib were significantly abolished by chronic pretreatment with the Rho-kinase-specific inhibitor fasudil. This study demonstrated that the multikinase inhibitor sorafenib protects NASH rats from IR injury by interfering with the inflammation, necrotic, and apoptotic responses causing leukocyte-dependent hepatic microcirculatory dysfunction. The hepatoprotective effects of sorafenib seem to work through the inhibition of the Rho-kinase-dependent Raf/MEK/ERK pathway, which is up-regulated during IR injury in the livers of NASH rats.

Protective effects of kaerophyllin against liver fibrogenesis in rats.

BACKGROUND: We previously demonstrated that kaerophyllin, a lignan, isolated from a widely used traditional Chinese herb, Bupleurum scorzonerifolium, leading to the inhibition of hepatic stellate cells (HSCs) activation in vitro. This current study evaluated the in vivo role of kaerophyllin in protecting the liver against injury and fibrogenesis caused by thioacetamide (TAA) in rats and further explored the underlying mechanisms. MATERIALS AND METHODS: Liver fibrosis in Sprague-Dawley rats was induced by intraperitoneal injection of TAA (200 mg/kg) twice per week for 6 weeks. Animals were divided into five groups: vehicle control, TAA control, TAA + low dose kaerophyllin, TAA + high dose kaerophyllin and TAA + curcumin groups. Kaerophyllin (10 or 30 mg/kg) or curcumin (150 mg/mL) was given by gavage twice per day consecutively for 4 weeks starting 2 weeks after TAA injection. Rat HSCs were used to investigate the anti-inflammatory role of kaerophyllin against tumour necrosis factor α (TNF-α) in vitro. Peroxisome proliferator-activated receptor-γ (PPAR-γ) expression was knocked down in rat HSCs using PPAR-γ small interfering RNAs. RESULTS: Kaerophyllin significantly protected liver from injury by reducing serum aspartate transaminase and alanine transaminase levels and by improving the histological architecture and fibrosis score. In addition, kaerophyllin suppressed inflammation by reducing the mRNA of TNF-α, interleukin-1ß (IL-1ß) and monocyte chemoattractant protein-1 (MCP-1) genes. In HSCs, kaerophyllin elevated PPAR-γ activity and reduced TNF-α-stimulated mRNA levels of intracellular adhesion molecule-1 (ICAM-1), MCP-1 and IL-1ß genes, which were reversed by small interfering RNA knockdown of PPAR-γ gene. CONCLUSIONS: Our results demonstrated that kaerophyllin protected the rat liver from TAA-caused injury and fibrogenesis by suppressing hepatic inflammation and inhibiting HSC activation, possibly through upregulation of PPAR-γ expression.

Kupffer cell depletion attenuates leptin-mediated methoxamine-stimulated portal perfusion pressure and thromboxane A2 release in a rodent model of NASH-cirrhosis.

Cirrhotic portal hypertension is characterized by increased hepatic oxidative stress, AA (arachidonic acid)-derived TXA(2) (thromboxane A(2)) release and exaggerated hepatic response to the α-adrenergic agonist MTX (methoxamine). Besides promoting hepatic fibrosis, the role of hyperleptinaemia in the modulation of vascular response in NASH (non-alcoholic steatohepatitis) rat livers remains unknown. The aim of the present study was to explore the possible links between hyperleptinaemia and the disarrangement in the hepatic microcirculation. NASH-cirrhosis with hyperleptinaemia was induced in lean rats by feeding with an HF/MCD (high-fat/methionine-choline-deficient) diet. Portal haemodynamics, various substances, protein and mRNA expression and PUFA (polyunsaturated fatty acid) composition were measured. Finally, the effects of leptin pre-infusion on TXA(2) release and concentration-PPP (portal perfusion pressure) curves in response to MTX were evaluated by simultaneously pre-treatment with the Kupffer cell inactivators GdCl(3) (gadolinium chloride) or EC (encapsulated clodronate), the TXS (TXA(2) synthase) inhibitor furegrelate, the TP receptor (TXA(2) receptor) antagonist SQ29548 and the dual TXS/TP receptor antagonist BM567. In HF/MCD+leptin-lean rats, cirrhosis-induced PPP and MTX hyper-responsiveness were associated with increased hepatic TXA(2) production, TBARS (thiobarbituric acid-reacting substances) levels and the AA (arachidonic acid)/n-3 PUFA ratio, and up-regulation of hepatic leptin, FAS (fatty acid synthase), NADPH oxidase subunits, TXS, TP receptor, TGFß(1) (transforming growth factor ß(1)) proteins and mRNAs. Pre-infusion of leptin significantly enhanced MTX-stimulated PPP elevation and TXA(2) release, which were attenuated by GdCl(3) and EC pre-treatment. Concomitantly pre-incubation with BM567, but not furegrelate or SQ29548, significantly abolished the leptin-enhanced MTX-stimulated increase in PPP in NASH-cirrhotic rats. Hyperleptinaemia plays an important role in hyper-responsiveness to MTX in NASH-cirrhotic rat livers with portal hypertension. The leptin-enhanced MTX-stimulated increase in PPP is mediated by increased oxidative stress and Kupffer-cell-activated AA-derived TXA(2) release in NASH-cirrhotic rats.

Asymmetric dimethylarginine (ADMA) determines the improvement of hepatic endothelial dysfunction by vitamin E in cirrhotic rats.

BACKGROUND: Hepatic endothelial dysfunction (HED), which is caused by decreased hepatic nitric oxide (NO) bioavailability and increased lipid peroxidation, contributes to portal hypertension, which is a characteristic of cirrhosis. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase (NOS), is involved in cirrhosis-related HED and portal hypertension. AIMS: We evaluated the effect of vitamin E treatment on the lipid peroxidation, HED and portal hypertension in cirrhotic rats. METHODS: The common bile duct ligation (BDL)-induced cirrhotic rats were treated orally either with vehicle or with vitamin E for 1 month immediately after BDL. Systemic and portal haemodynamics, the magnitude of the increase in portal pressure induced by volume expansion, HED, oxidative stress, levels of ADMA, various proteins and mRNAs were then measured. RESULTS: In the vitamin E-treated BDL rats, a decrease in portal pressure was associated with an attenuation of the increased portal pressure induced by volume expansion. In isolated and perfused BDL rat livers, the vitamin E treatment significantly inhibited the (paradoxical) vasoconstriction response to methoxamine and acetylcholine (HED), and this was abolished by the presence of NOS. Vitamin E decreased ADMA synthesizing enzyme PRMT1 expression and the level of thiobarbituric acid-reactive substances (TBARS) in the liver, while increasing the levels of hepatic ADMA metabolizing enzyme DDAH2, eNOS, phosphor-eNOS, ADMA level and superoxide dismutase activity. CONCLUSIONS: The administration of vitamin E suppressed hepatic ADMA and oxidative stress in the cirrhotic liver circulation, and therefore increases NO bioavailability, which improved HED and portal hypertension.

Paeoniae radix reduces PDGF-stimulated hepatic stellate cell migration.

Hepatic stellate cells (HSCs) play a key role in the pathogenesis of liver fibrosis. In chronic liver injury, HSCs undergo transdifferentiation to an activated myofibroblastic phenotype and migrate to injured areas in response to chemotactic factors, producing extracellular matrix proteins such as collagen type I to repair the damage as well as overexpression of α-smooth muscle actin (α-SMA). Paeoniae Radix, the root of Paeonia lactiflora Pall, was investigated for PDGF-BB-induced HSC chemotaxis. Rat HSCs and LX-2, a human HSC cell line, were used for the in vitro experiments. Cell migration was analyzed by wound-healing and transwell assays. An ELISA and a Sircol collagen assay kit were used to detect the expressions of α-SMA and of collagen, respectively. Phosphorylations of mitogen-activated protein kinases, including ERK 1/2, p38, and JNK, were evaluated with immunoblotting. Results indicated that PDGF-BB increased migration as well as α-SMA and collagen expression in HSCs. Paeoniae Radix extracts and its active components, paeonol and 1,2,3,4,6-penta- O-galloyl- ß-D-glucose (PGG), inhibited PDGF-BB-induced HSC migration and α-SMA and collagen expressions in a concentration-dependent manner. The inhibitory effects were associated with downregulation of PDGF receptor- α, ERK, p38, and JNK activation. Both paeonol and PGG participate in HSC migration, but via differential mechanisms.

Effects of armepavine against hepatic fibrosis induced by thioacetamide in rats.

The aim of this study was to investigate if armepavine (Arm, C19H23O3N) could exert inhibitory effects against hepatic fibrosis in rats. A cell line of rat hepatic stellate cells (HSC-T6) was stimulated with tumour necrosis factor-α (TNF-α) to evaluate the inhibitory effects of Arm. Rats were injected with thioacetamide (TAA; 300 mg/kg, intraperitoneally) thrice a week for 4 weeks to induce hepatic fibrosis, with Arm (3 or 10 mg/kg) given by gavage twice a day. Liver sections were taken for western blotting, fibrosis scoring and immunofluorescence staining. Arm (1-10 µm) concentration-dependently attenuated TNF-α-stimulated: (i) protein expressions of α-smooth muscle actin (α-SMA), collagen type I and angiopoietin-1; (ii) H2O2 production; and (iii) NF-κB, JunD and C/EBPß (cytidine-cytidine-adenosine-adenosine-thymidine (CCAAT)/enhancer binding protein-ß (EBPß)) nuclear translocations in HSC-T6 cells. In vivo Arm treatment significantly reduced plasma aspartate transaminase and alanine transaminase levels, hepatic α-SMA expression and collagen contents, and fibrosis scores of TAA-injected rats. Moreover, Arm treatment decreased α-SMA- and NF-κB-positive cells in immunohistochemical staining, and mRNA expression levels of IL-6, TGF-ß1, TIMP-1, col1α2, iNOS and ICAM-1 genes, but up-regulated the metallothionein gene in the livers of TAA-injected rats. Our results indicated that Arm exerted both in vitro and in vivo antifibrotic effects in rats, with inhibition of NF-κB, JunD and C/EBPß pathways.

The relationship between endotoxemia and hepatic endocannabinoids in cirrhotic rats with portal hypertension.

BACKGROUND & AIMS: Cirrhosis is characterized by endotoxemia and increased intrahepatic resistance, which is caused by hepatic fibrosis and endothelial dysfunction, as well as the activated endocannabinoids system, including cannabinoid (CB(1) and CB(2)) receptors. Besides accelerating hepatic fibrogenesis, endotoxins induce the release of circulating endocannabinoids and portal hypertension in cirrhosis. This study examines how suppression of endotoxemia by antibiotics affects intrahepatic resistance and the hepatic endocannabinoid system in bile-duct-ligated (BDL) rats. METHODS: Measurements were performed that included: mean arterial pressure, cardiac index (CI), systemic vascular resistance, superior mesenteric arterial blood flow and resistance, PVP, plasma endotoxin and hepatic tumor necrosis factor-α (TNFα), anandamide and 2-arachidonylglycerol, hepatic expression of cannabinoid receptors, endothelial nitric oxide synthase (eNOS), phospho-eNOS, Akt, phospho-Akt and thromboxane synthase (TXS), matrix metalloproteinase-2 (MMP-2), tissue inhibitor of metalloproteinase-2 (TIMP-2), hepatic fibrosis, and leukocyte infiltration. Hepatic endothelial dysfunction was evaluated in BDL rats receiving vehicle (BDL-V) or 2-weeks of ciprofloxacin (BDL-cipro). RESULTS: Plasma endotoxin and hepatic TNFα, anandamide and 2-arachidonylglycerol, expression of TXS, MMP-2, TIMP-2, hepatic fibrosis and infiltration of hepatic leukocytes, CI, PVP and intrahepatic resistance were significantly lower in BDL-cipro than in BDL-V rats. Conversely, systemic vascular resistance, eNOS and Akt phosphorylation were significantly higher in BDL-cipro than in BDL-V rats. Improvement of hepatic endothelial dysfunction was associated with lower expression of hepatic CB(1) and a higher expression of hepatic CB(2) in BDL-cipro rats. CONCLUSIONS: In cirrhotic rats, ciprofloxacin suppressed endotoxemia and the hepatic endocannabinoid system thus ameliorating hyperdynamic circulation and decreased intrahepatic resistance by preventing hepatic fibrogenesis and endothelial dysfunction.

Kaerophyllin inhibits hepatic stellate cell activation by apoptotic bodies from hepatocytes.

BACKGROUND: Hepatic stellate cells (HSCs), the key cell type for hepatic fibrosis, become activated and profibrogenic in the presence of hepatocyte apoptotic bodies (ABs). Bupleurum scorzonerifolium (BS), a widely used traditional Chinese herb for liver diseases, was fractionated, and the inhibitory effects of BS extracts on AB-induced HSC migration were screened. The activity-guided fractionation led to a lignan, kaerophyllin. In this study, the anti-fibrotic effects of kaerophyllin were studied in the presence of ABs. METHODS: LX-2 cells phagocytosing ultraviolet (UV)-induced HepG2 ABs were investigated by confocal microscopy and flow cytometry. AB-induced HSC activation was evaluated by immunoblotting and real-time PCR analyses. HSC migration was measured by wound-healing assays. RESULTS: HepG2 ABs induced LX-2 activation, with the production of collagen I and α-smooth muscle actin, upregulated profibrogenic gene transcriptions and increased NF-κB activity, cell migration and phagocytosis. Kaerophyllin from BS antagonized AB-induced HSC migration and activation. CONCLUSIONS: Kaerophyllin inhibited AB-induced LX-2 activation and migration with downregulation of Akt/ERK phosphorylations and NF-κB activity. Our study suggests a novel platform for screening anti-fibrotic compounds with ABs.

Differential inhibitory effects of salvianolic acids on activation of rat hepatic stellate cells by platelet-derived growth factor.

Platelet-derived growth factor (PDGF) induces cell proliferation together with oxidative stress. The present study investigated the effects of salvianolic acid A (Sal A) and B (Sal B) on the PDGF-induced signaling cascades in hepatic stellate cells (HSCs). HSC-T6, a rat hepatic stellate cell line, was stimulated with PDGF (10 ng/mL). The inhibitory effects of Sal A and B on oxidative stress-related signaling pathways were assessed in vitro. The protein levels were measured by Western blotting. FACS analysis was applied to detect the thioredoxin (Trx) level. Sal A and B showed different inhibitory abilities on the PDGF-related pathway. Sal A inhibited 70-kDa ribosomal S6 kinase (p70(s6k)) and associated proteins. Sal B attenuated PDGF-induced c-jun-N-terminal kinase (JNK), p38, and PKC- δ phosphorylations. Both Sal A and B diminished the activation of PKD, Trx, heme-oxygenase (HO)-1, and Nrf2. Taken together, our results showed that Sal A and B attenuated PDGF-induced ROS formation in HSCs, possibly through different signaling pathways.

Antifibrotic effects of triptolide on hepatic stellate cells and dimethylnitrosamine-intoxicated rats.

Triptolide (C38H42O6N2, TP, a diterpene triepoxide derived from Tripterygium wilfordii Hook F.), is a potent immunosuppresive and antiinflammatory agent. The present study investigated whether TP exerted antihepatofibrotic effects in vitro and in vivo. A cell line of rat hepatic stellate cells (HSC-T6) was stimulated with tumor necrosis factor-α (TNF-α) or transforming growth factor (TGF)-ß1. The inhibitory effects of TP on the nuclear factor-κB (NFκB) signaling cascade and fibrosis markers, including α-smooth muscle actin (α-SMA) and collagen, were assessed. An in vivo therapeutic study was conducted in dimethylnitrosamine (DMN)-treated rats. The rats were randomly assigned to one of three groups: control rats, DMN rats receiving vehicle only and DMN rats receiving TP (20 µg/kg). Treatment was given by gavage twice daily for 3 weeks starting 1 week after the start of DMN administration. TP (5-100 nM) concentration-dependently inhibited the NFκB transcriptional activity induced by TNF-α, lipopolysaccharide and phorbol 12-myristate 13-acetate in HSC-T6 cells. In addition, TP also suppressed TNF-α and TGF-ß1-induced collagen deposition and α-SMA secretion in HSC-T6 cells. In vivo, TP treatment significantly reduced hepatic fibrosis scores, collagen contents, IL-6 and TNF-α levels, and the number of α-SMA and NFκB-positive cells in DMN rats. The results showed that TP exerted antifibrotic effects in both HSC-T6 cells and DMN rats.