Hepatic fibrosis -- overview

Restorative effects of hydroxysafflor yellow A on hepatic function in an experimental regression model of hepatic fibrosis induced by carbon tetrachloride

Hepatic fibrosis is a reversible pathological process, in which fibrotic tissue is excessively deposited in the liver during the repair process that follows hepatic injury. Early prevention or treatment of hepatic fibrosis has great significance on the treatment of chronic hepatic diseases. Hydroxysafflor yellow A (HSYA) is a water-soluble monomer extracted from safflower, which serves numerous pharmacological roles. However, it remains to be elucidated how HSYA regulates hepatic fibrogenesis. The aim of the present study was to reveal the possible mechanisms underlying the effects of HSYA on the prevention and treatment of hepatic fibrosis. A rat model of hepatic fibrosis was established in the present study, and the rats were administered various doses of HSYA. The effects of HSYA on pathological alterations of the liver tissue in rats with hepatic fibrosis were observed using hematoxylin-eosin staining and Masson staining. In order to explore the anti-hepatic fibrosis effects and underlying mechanisms of HSYA, serum levels, and hepatic function and hepatic fibrosis indices were evaluated. The results demonstrated that HSYA can improve the general condition of rats with hepatic fibrosis and relieve cellular swelling of the liver, fatty degeneration, necrosis, inflammatory cell infiltration and fibroplastic proliferation. Subsequent to administration of HSYA, globulin was increased during hepatic fibrosis caused by tetrachloromethane. However, total cholesterol, triglyceride, alanine aminotransferase, aspartate aminotransferase and levels of hyaluronic acid, laminin, procollagen III N-terminal peptide, collagen type IV and hydroxyproline were significantly reduced. The results additionally demonstrated that HSYA could enhance superoxide dismutase activity and reduce malondialdehyde levels, inhibiting lipid peroxidation caused by free radicals.

Retinol dehydrogenase 13 deficiency diminishes carbon tetrachloride-induced liver fibrosis in mice

Retinol dehydrogenase 13 (RDH13) is a mitochondrion-localized member of the short-chain dehydrogenases/reductases (SDRs) superfamily that participates in metabolism of some compounds. Rdh13 mRNA is most highly expressed in mouse liver. Rdh13 deficiency reduces the extent of liver injury and fibrosis, reduces hepatic stellate cell (HSC) activation, attenuates collagen I (II), tissue inhibitor of metalloproteinase 1 (TIMP-1) and transforming growth factor beta 1 (Tgf-β1) expression. The results indicate an important role of Rdh13 and suggest RDH13 as a possible new therapeutic target for CCl₄-induced fibrosis.

Effects of Melatonin on Differentiation Potential of Ito Cells in Mice with Induced Fibrosis of the Liver

We studied the effects of melatonin on differentiation potential of Ito cells during atypical regeneration of mouse liver under conditions of CCl₄-induced fibrosis. The dynamics of fibrosis was traced at the histological level and the effects of melatonin on the differentiation potential of mouse Ito cells were evaluated. Melatonin alleviated fibrotic changes in the liver tissue and reduced differentiation of Ito cells into myofibroblasts under conditions of atypical regeneration of the liver in induced fibrosis. The hepatoprotective role of melatonin was shown.

Collapsed Reticular Network and its Possible Mechanism during the Initiation and/or Progression of Hepatic Fibrosis

Among the researches on hepatic fibrosis, great attention was paid to both hepatocytes and extracellular matrix (ECM). However, little focus was drawn on reticular fibrous network, which is important for demarcation and support of hepatocytes. The aim of this study was to investigate the change pattern of reticular fibers in hepatic fibrosis/cirrhosis and its underlying mechanism. In this study, thioacetamide (TAA) and bile duct ligation (BDL) were utilized to induce rat hepatic fibrosis respectively, and Human liver cirrhotic microassay was analyzed with IHC to confirm the results in animal experiment and to detect the metalloproteinases (MMPs) expressions. As a result, the reticular fibers decreased markedly after 1 week in TAA and 1 day in BDL treated rats. Multiple representative regulators of MMPs and MMPs increased significantly in their expressions and activities. Further more, in human liver cirrhotic microassay, MMPs expressions also showed similar patterns as that of animal experiment. In Conclusions: Degradation or collapse of reticular fibers in hepatic sinusoid can be considered as a pathological feature during the initiation and/or progression of hepatic fibrosis. Moreover, such degradation is associated with and probably caused by the over/dysregulated expression of MMPs.

Fibrogenic Signaling Is Suppressed in Hepatic Stellate Cells through Targeting of Connective Tissue Growth Factor (CCN2) by Cellular or Exosomal MicroRNA-199a-5p

Pathways of liver fibrosis are controlled by connective tissue growth factor (CCN2). In this study, CCN2 was identified as a target of miR-199a-5p, which was principally expressed in quiescent mouse hepatic stellate cells (HSCs) and directly suppressed production of CCN2. Up-regulated CCN2 expression in fibrotic mouse livers or in activated primary mouse HSCs was associated with miR-199a-5p down-regulation. MiR-199a-5p in quiescent mouse HSCs inhibited the activity of a wild-type CCN2 3' untranslated region (3'-UTR) but not of a mutant CCN2 3'-UTR lacking the miR-199a-5p-binding site. In activated mouse HSCs, CCN2, α-smooth muscle actin, and collagen 1(α1) were suppressed by a miR-199a-5p mimic, whereas in quiescent mouse HSCs, the inhibited CCN2 3'-UTR activity was blocked by a miR-199a-5p antagomir. CCN2 3'-UTR activity in human HSCs was reduced by a miR-199a-5p mimic. MiR-199a-5p was present at higher levels in exosomes from quiescent versus activated HSCs. MiR-199a-5p-containing exosomes were shuttled from quiescent mouse HSCs to activated mouse HSCs in which CCN2 3'-UTR activity was then suppressed. Exosomes from quiescent HSCs caused miR-199a-5p-dependent inhibition of CCN2, α-smooth muscle actin, or collagen 1(α1) in activated HSCs in vitro and bound to activated HSCs in vivo. Thus, CCN2 suppression by miR-199a-5p accounts, in part, for low-level fibrogenic gene expression in quiescent HSCs and causes dampened gene expression in activated HSCs after horizontal transfer of miR-199a-5p in exosomes from quiescent HSCs.

Moniliformediquinone as a potential therapeutic agent, inactivation of hepatic stellate cell and inhibition of liver fibrosis in vivo

Background

Moniliformediquinone (MFD), a phenanthradiquinone in Dendrobium moniliforme, was synthesized in our laboratory. Beyond its in vitro inhibitory effects on cancer cells, other biological activity of MFD is unknown. The purpose of the present study was to investigate the effects of MFD on hepatic fibrogenesis in vitro and in vivo.

Methods

Hepatic stellate HSC-T6 was cultured. Cell viability assay and western blot analyses were performed. Male ICR mice were evaluated on CCl₄-induced hepatotoxicity using both histological examination and immunohistochemical staining.

Results

First, in vitro study showed that the synthesized MFD effectively attenuated the expression of transforming growth factor-β1 (TGF-β1), connective tissue growth factor (CTGF), α-smooth muscle actin (α-SMA), and type I collagen (COL-1), which modulated the hepatic fibrogenesis. Furthermore, MFD reduced the phosphorylation of p65 NFκB in HSC-T6 cells. In vivo, liver fibrosis was induced by CCl₄ twice a week for 10 weeks in mice. The administration of the MFD was started after 1 week of CCl₄ thrice-weekly; the MFD significantly reduced plasma aspartate transaminase (AST) and lactose dehydrogenase (LDH) as well as hepatic hydroxy-proline, α-SMA, and COL-1 expression in CCl₄-treated mice. Pathological analysis showed that the MFD alleviated CCl₄-induced hepatic inflammation, necrosis and fibrosis. These results suggest that MFD possesses therapeutic potential for liver fibrosis.

Conclusions

The synthesized MFD exhibits anti-fibrotic potential by inactivation of HSCs in vitro and decreases mouse hepatic fibrosis in vivo. Further investigation into their clinical therapeutic potential is required.

Black blood T1rho MR imaging may diagnose early stage liver fibrosis: a proof-of-principle study with rat biliary duct ligation model

BACKGROUND

To explore black blood T1rho (T1ρ) liver imaging and investigate the earliest stage when biliary duct ligation (BDL) induced liver fibrosis can be diagnosed.

METHODS

MR was performed at 3 Tesla. A T1ρ prepared 2D fast spin echo (FSE) sequence with acquisition of four spin lock times (TSLs: 1, 10, 30, and 50 msec) and spin-lock frequency of 500 Hz was applied. Inherent black blood effect of FSE and double inversion recovery (DIR) achieved blood signal suppression, and 3 axial sections per liver were obtained. Male Sprague-Dawley rats were scanned at baseline (n=32), and on day-3 (n=13), day-5 (n=11), day-7 (n=10), day-10 (n=4) respectively after BDL. Hematoxylin-eosin (HE) and picrosirius red staining liver histology was obtained at these time points.

RESULTS

The physiological liver parenchyma T1ρ was 38.38±1.53 msec (range, 36.05-41.53 msec). Liver T1ρ value elevated progressively after BDL. On day-10 after BDL all experimental animals can be separated from normal liver based on T1ρ measurement with lowest value being 42.82 msec. Day-7 and day-10 liver resembled METAVIR stage-F1/F2 fibrosis, and fibrous area counted for 0.22%±0.13% and 0.38%±0.44% of liver parenchyma area, respectively.

CONCLUSIONS

This study provides the first proof-of-principle that T1ρ might diagnose early stage liver fibrosis.

Niemann-Pick Type C2 Protein Mediates Hepatic Stellate Cells Activation by Regulating Free Cholesterol Accumulation

In chronic liver diseases, regardless of their etiology, the development of fibrosis is the first step toward the progression to cirrhosis, portal hypertension, and hepatocellular carcinoma. Hepatic stellate cells (HSCs) are the main profibrogenic cells that promote the pathogenesis of liver fibrosis, and so it is important to identify the molecules that regulate HSCs activation and liver fibrosis. Niemann-Pick type C2 (NPC2) protein plays an important role in the regulation of intracellular cholesterol homeostasis by directly binding with free cholesterol. However, the roles of NPC2 in HSCs activation and liver fibrosis have not been explored in detail. Since a high-cholesterol diet exacerbates liver fibrosis progression in both rodents and humans, we propose that the expression of NPC2 affects free cholesterol metabolism and regulates HSCs activation. In this study, we found that NPC2 is decreased in both thioacetamide- and carbon tetrachloride-induced liver fibrosis tissues. In addition, NPC2 is expressed in quiescent HSCs, but its activation status is down-regulated. Knockdown of NPC2 in HSC-T6 cells resulted in marked increases in transforming growth factor-β1 (TGF-β1)-induced collagen type 1 α1 (Col1a1), α-smooth muscle actin (α-SMA) expression, and Smad2 phosphorylation. In contrast, NPC2 overexpression decreased TGF-β1-induced HSCs activation. We further demonstrated that NPC2 deficiency significantly increased the accumulation of free cholesterol in HSCs, increasing Col1a1 and α-SMA expression and activating Smad2, and leading to sensitization of HSCs to TGF-β1 activation. In contrast, overexpression of NPC2 decreased U18666A-induced free cholesterol accumulation and inhibited the subsequent HSCs activation. In conclusion, our study has demonstrated that NPC2 plays an important role in HSCs activation by regulating the accumulation of free cholesterol. NPC2 overexpression may thus represent a new treatment strategy for liver fibrosis.

Role of histone deacetylases(HDACs) in progression and reversal of liver fibrosis

Liver fibrosis refers to a reversible wound healing process response to chronic liver injuries. Activation of hepatic stellate cells (HSCs) is closely correlated with the development of liver fibrosis. Histone deacetylases(HDACs) determine the acetylation levels of core histones to modulate expression of genes. To demonstrate the link between HDACs and liver fibrosis, CCl4-induced mouse liver fibrosis model and its spontaneous reversal model were established. Results of the current study demonstrated that deregulation of liver HDACs may involved in the development of liver fibrosis. Among 11 HDACs tested in our study (Class I, II, and IV HDACs), expression of HDAC2 was maximally increased in CCl4-induced fibrotic livers but decreased after spontaneous recovery. Moreover, expression of HDAC2 was elevated in human liver fibrotic tissues. In this regard, the potential role of HDAC2 in liver fibrosis was further evaluated. Our results showed that administration of HSC-T6 cells with transforming growth factor-beta1 (TGF-β1) resulted in an increase of HDAC2 protein expression in dose- and time-dependent manners. Moreover, HDAC2 deficiency inhibited HSC-T6 cell proliferation and activation induced by TGF-β1. More importantly, the present study showed HDAC2 may regulate HSCs activation by suppressing expression of Smad7, which is a negative modulator in HSCs activation and liver fibrosis. Collectively, these observations revealed that HDAC2 may play a pivotal role in HSCs activation and liver fibrosis while deregulation of HDACs may serve as a novel mechanism underlying liver fibrosis.

MicroRNA-19b reduces hepatic stellate cell proliferation by targeting GRB2 in hepatic fibrosis models in vivo and in vitro as part of the inhibitory effect of estradiol

Estradiol (E2) is a major determinant of gender-based differences in the development of hepatic fibrosis. MicroRNAs (miRNAs) are endogenous 19-25 nucleotide, noncoding, single-stranded RNAs that regulate gene expression by blocking the translation or decreasing the stability of mRNAs and play an important role in liver fibrosis. The mechanisms underlying the regulation of miRNAs by E2 remain largely unknown. In this study, miR-19b levels were higher and were associated with lower GRB2 mRNA and protein levels in female rats more than in male rats. We also showed that miR-19b levels were down-regulated, were associated with the up-regulation of GRB2 mRNA and protein levels in PS (porcine serum-induced hepatic fibrosis) versus NS (normal control) groups and were up-regulated when associated with the down-regulation of GRB2 mRNA and protein levels in PS + E2 versus PS and in aHSC + E2 (estradiol treated aHSC) versus aHSC groups. MiR-19b expression inhibited cell proliferation in aHSCs, and also down-regulated GRB2 protein expression. The overexpression of miR-19b inhibited cell growth and suppressed COL1A1 protein levels by decreasing the levels of GRB2. However, the forced expression of GRB2 partly rescued the effect of miR-19b in the cells, attenuated cell proliferation, and suppressed the GRB2 protein level by up-regulating the levels of GRB2. Taken together, these findings will shed light on the role of miR-19b in regulating aHSC proliferation via the miR-19b/GRB2 axis. This newly identified miR-19b/GRB2 interaction provided novel insights into the suppressive effect of E2 on HSC proliferation and might facilitate the development of therapies targeting hepatic fibrosis.

The 11β-hydroxysteroid dehydrogenase type 1 inhibitor protects against the insulin resistance and hepatic steatosis in db/db mice

Glucocorticoids (GCs) metabolism is regulated by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). When GCs are present in excess, they can impair glucose-dependent insulin sensitivity. We have previously synthesized several curcumin analogues, of which four compounds were selective inhibitors of 11β-HSD1. Here, we present data supporting that the 11β-hydroxysteroid dehydrogenase type 1 inhibitor (H8) inhibits insulin resistance and ameliorates hepatic steatosis in db/db mice. We compared glucose and lipid metabolism in db/db mice with or without administration of H8, which significantly decreased fasting blood glucose levels and protected against insulin resistance and hepatic steatosis compared to when glucose and lipid metabolism were measured following curcumin administration. The hepatic enzyme was reduced significantly in the plasma samples from db/db mice which were treated with H8. Serum corticosterone (active) levels, which are regulated by 11β-HSD1 were reduced when mice received H8. H8 administration suppressed phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6-pase) expression, which are related to gluconeogenesis and enhanced glucose transporter 4 (GLUT4) protein content in liver. Treatment with H8 improved obesity and metabolic disorders, such as insulin resistance and hepatic steatosis by suppressing activity of 11β-HSD1, suggesting that H8 might be a beneficial drug for the treatment of obesity and Type-2 diabetes (T2D).

Breath-hold black blood quantitative T1rho imaging of liver using single shot fast spin echo acquisition

BACKGROUND

Liver fibrosis is a key feature in most chronic liver diseases. T1rho magnetic resonance imaging is a potentially important technique for noninvasive diagnosis, severity grading, and therapy monitoring of liver fibrosis. However, it remains challenging to perform robust T1rho quantification of liver on human subjects. One major reason is that the presence of rich blood signal in liver can cause artificially high T1rho measurement and makes T1rho quantification susceptible to motion.

METHODS

A pulse sequence based on single shot fast/turbo spin echo (SSFSE/SSTSE) acquisition, with theoretical analysis and simulation based on the extended phase graph (EPG) algorithm, was presented for breath-hold single slice quantitative T1rho imaging of liver with suppression of blood signal. The pulse sequence was evaluated in human subjects at 3.0 T with 500 Hz spinlock frequency and time-of-spinlock (TSL) 0, 10, 30 and 50 ms.

RESULTS

Human scan demonstrated that the entire T1rho data sets with four spinlock time can be acquired within a single breath-hold of 10 seconds with black blood effect. T1rho quantification with suppression of blood signal results in significantly reduced T1rho value of liver compared to the results without blood suppression.

CONCLUSIONS

A signal-to-noise ratio (SNR) efficient pulse sequence was reported for T1rho quantification of liver. The black blood effect, together with a short breath-hold, mitigates the risk of quantification errors as would occur in the conventional methods.

Scanning and transmission electron microscopy of the cells forming the hepatic sinusoidal wall of rat in acetaminophen and Escherichia coli endotoxin-induced hepatotoxicity

Drugs and xenobiotics as well as bacterial endotoxins may reach the liver either systematically or after intestinal absorption. Therefore, cells lining the sinusoidal wall form the last barrier before blood constituents get in contact with the parenchymal cells. In this work, the ultrastructure of the cells forming the sinusoidal wall was studied after acetaminophen and Escherichia coli endotoxin treatments. Rats received acetaminophen at a dose of 1000 mg/kg body weight by intraperitoneal injection once in acute and four times with a 1-week interval in chronic treatments, and E. coli endotoxin at a dose of 5 mg/kg of body weight by intraperitoneal injection once in acute and four times with a 1-week interval in chronic treatments. Tissue samples were collected for scanning and transmission electron microscopy. Swelling of sinusoidal endothelial cells was noticed in both acute intoxicated groups with narrowing of the fenestrae, whereas large gaps were formed in chronic toxicity. Activation of Kupffer cells was a prominent common feature between the four toxicity groups. Interestingly, hepatic stellate cell activation was evident in both chronic acetaminophen and chronic endotoxin groups. Large amounts of collagen fibers were seen surrounding the hepatic stellate cells and in Disse space.

Calcium channel blockers ameliorate iron overload-associated hepatic fibrosis by altering iron transport and stellate cell apoptosis

Liver fibrosis is the principal cause of morbidity and mortality in patients with iron overload. Calcium channel blockers (CCBs) can antagonize divalent cation entry into renal and myocardial cells and inhibit fibrogenic gene expression. We investigated the potential of CCBs to resolve iron overload-associated hepatic fibrosis. Kunming mice were assigned to nine groups (n=8 per group): control, iron overload, deferoxamine, high and low dose verapamil, high and low dose nimodipine, and high and low dose diltiazem. Iron deposition and hepatic fibrosis were measured in mouse livers. Expression levels of molecules associated with transmembrane iron transport were determined by molecular biology approaches. In vitro HSC-T6 cells were randomized into nine groups (the same groups as the mice). Changes in proliferation, apoptosis, and metalloproteinase expression in cells were detected to assess the anti-fibrotic effects of CCBs during iron overload conditions. We found that CCBs reduced hepatic iron content, intracellular iron deposition, the number of hepatic fibrotic areas, collagen expression levels, and hydroxyproline content. CCBs rescued abnormal expression of α1C protein in L-type voltage-dependent calcium channel (LVDCC) and down-regulated divalent metal transporter-1 (DMT-1) expression in mouse livers. In iron-overloaded HSC-T6 cells, CCBs reduced iron deposition, inhibited proliferation, induced apoptosis, and elevated expression of matrix metalloproteinase-13 (MMP-13) and tissue inhibitor of metalloproteinase-1 (TIMP-1). CCBs are potential therapeutic agents that can be used to address hepatic fibrosis during iron overload. They resolve hepatic fibrosis probably correlated with regulating transmembrane iron transport and inhibiting HSC growth.

Versican: a novel modulator of hepatic fibrosis

Little is known about the deposition and turnover of proteoglycans in liver fibrosis, despite their abundance in the extracellular matrix. Versican plays diverse roles in modulating cell behavior in other fibroproliferative diseases, but remains poorly described in the liver. Hepatic fibrosis was induced by carbon tetrachloride treatment of C57BL/6 mice over 4 weeks followed by recovery over a 28-day period. Primary mouse hepatic stellate cells (HSCs) were activated in culture and versican was transiently knocked down in human (LX2) and mouse HSCs. Expression of versican, A Disintegrin-like and Metalloproteinase with Thrombospondin-1 motifs (ADAMTS)-1, -4, -5, -8, -9, -15, and -20, and markers of fibrogenesis were studied using immunohistochemistry, real-time quantitative PCR, and western blotting. Immunohistochemistry showed increased expression of versican in cirrhotic human livers and the mouse model of fibrosis. Carbon tetrachloride treatment led to significant increases in versican expression and the proteoglycanases ADAMTS-5, -9, -15, and -20, alongside TNF-α, α-smooth muscle actin (α-SMA), collagen-1, and TGF-β expression. During recovery, expression of many of these genes returned to control levels. However, expression of ADAMTS-5, -8, -9, and -15 showed delayed increases in expression at 28 days of recovery, which corresponded with decreases in versican V0 and V1 cleavage products (G1-DPEAAE(1401) and G1-DPEAAE(441)). Activation of primary HSCs in vitro significantly increased versican, α-SMA, and collagen-1 expression. Transient knockdown of versican in HSCs led to decreases in markers of fibrogenesis and reduced cell proliferation, without inducing apoptosis. Versican expression increases during HSC activation and liver fibrosis, and proteolytic processing occurs during the resolution of fibrosis. Knockdown studies in vitro suggest a possible role of versican in modulating hepatic fibrogenesis.

Phlorizin Supplementation Attenuates Obesity, Inflammation, and Hyperglycemia in Diet-Induced Obese Mice Fed a High-Fat Diet

Obesity, along with its related complications, is a serious health problem worldwide. Many studies reported the anti-diabetic effect of phlorizin, while little is known about its anti-obesity effect. We investigated the beneficial effects of phlorizin on obesity and its complications, including diabetes and inflammation in obese animal. Male C57BL/6J mice were divided into three groups and fed their respective experimental diets for 16 weeks: a normal diet (ND, 5% fat, w/w), high-fat diet (HFD, 20% fat, w/w), or HFD supplemented with phlorizin (PH, 0.02%, w/w). The findings revealed that the PH group had significantly decreased visceral and total white adipose tissue (WAT) weights, and adipocyte size compared to the HFD. Plasma and hepatic lipids profiles also improved in the PH group. The decreased levels of hepatic lipids in PH were associated with decreased activities of enzymes involved in hepatic lipogenesis, cholesterol synthesis and esterification. The PH also suppressed plasma pro-inflammatory adipokines levels such as leptin, adipsin, tumor necrosis factor-α, monocyte chemoattractant protein-1, interferon-γ, and interleukin-6, and prevented HFD-induced collagen accumulation in the liver and WAT. Furthermore, the PH supplementation also decreased plasma glucose, insulin, glucagon, and homeostasis model assessment of insulin resistance levels. In conclusion, phlorizin is beneficial for preventing diet-induced obesity, hepatic steatosis, inflammation, and fibrosis, as well as insulin resistance.

Protective effect of fucoidan from Fucus vesiculosus on liver fibrosis via the TGF-β1/Smad pathway-mediated inhibition of extracellular matrix and autophagy

Liver fibrosis is a dynamic reversible pathological process in the development of chronic liver disease to cirrhosis. However, the current treatments are not administered for a long term due to their various side effects. Autophagy is initiated to decompose damaged or excess organelles, which had been found to alter the progression of liver fibrosis. In this article, we hypothesized that fucoidan from Fucus vesiculosus may attenuate liver fibrosis in mice by inhibition of the extracellular matrix and autophagy in carbon tetrachloride- and bile duct ligation-induced animal models of liver fibrosis. The results were determined using enzyme-linked immunosorbent assay, quantitative real-time polymerase chain reaction, Western blotting, and immunohistochemical staining. Fucoidan from F. vesiculosus could inhibit the activation of hepatic stellate cells and the formation of extracellular matrix and autophagosomes, and its effect may be associated with the downregulation of transforming growth factor beta 1/Smads pathways. Fucoidan, as an autophagy and transforming growth factor beta 1 inhibitor, could be a promising potential therapeutic agent for liver fibrosis.

Serum Metabolomic Characterization of Liver Fibrosis in Rats and Anti-Fibrotic Effects of Yin-Chen-Hao-Tang

Yin-Chen-Hao-Tang (YCHT) is a famous Chinese medicine formula which has long been used in clinical practice for treating various liver diseases, such as liver fibrosis. However, to date, the mechanism for its anti-fibrotic effects remains unclear. In this paper, an ultra-performance liquid chromatography-time-of-flight mass spectrometry (UPLC-TOF-MS)-based metabolomic study was performed to characterize dimethylnitrosamine (DMN)-induced liver fibrosis in rats and evaluate the therapeutic effects of YCHT. Partial least squares-discriminant analysis (PLS-DA) showed that the model group was well separated from the control group, whereas the YCHT-treated group exhibited a tendency to restore to the controls. Seven significantly changed fibrosis-related metabolites, including unsaturated fatty acids and lysophosphatidylcholines (Lyso-PCs), were identified. Moreover, statistical analysis demonstrated that YCHT treatment could reverse the levels of most metabolites close to the normal levels. These results, along with histological and biochemical examinations, indicate that YCHT has anti-fibrotic effects, which may be due to the suppression of oxidative stress and resulting lipid peroxidation involved in hepatic fibrogenesis. This study offers new opportunities to improve our understanding of liver fibrosis and the anti-fibrotic mechanisms of YCHT.

Antifibrotic compounds from Liriodendron tulipifera attenuating HSC-T6 proliferation and TNF-α production in RAW264.7 cells

The inhibition of hepatic stellate cell (HSC) proliferation has been considered as an effective therapeutic target for the treatment of liver fibrosis. The methanolic extract of Liriodendron tulipifera showed significant inhibitory activity against the proliferation of HSCs. Bioactivity-guided isolation afforded twelve compounds including (-)-sesamin (1), (-)-syringaresinol (2), (+)-dihydrodehydrodiconiferyl alcohol (3), salvinal (4), (+)-guaiacylglycerol-8-O-4'-dihydroconiferyl ether (5), (±)-guaiacylglycerol-8-O-4'-sinapyl alcohol ether (6), tanegool (7), (+)-5,5'-dimethoxy-7-oxolariciresinol (8), 3-hydroxy-4-methoxyacetophenone (9), 4-acetoxymethylphenol (10), (-)-paramicholide (11), and blumenol A (12). Among the compounds isolated, 2, 3 and 4 significantly attenuated the proliferation of the activated HSC-T6 cells. The maximal dose of these compounds, however, showed no cytotoxicity in primary cultured rat hepatocytes. Collagen deposition in the activated HSC-T6 cells was reduced by 2, 3 and 4. Also, the increased production of the pro-inflammatory cytokine tumor necrosis factor (TNF)-α induced by lipopolysaccharide was decreased by 3 and 4 in RAW264.7 macrophage cells. Collectively, (-)-syringaresinol (2), (+)-dihydrodehydrodiconiferyl alcohol (3), and salvinal (4) isolated from L. tulipifera leaves and twigs exhibited selective antifibrotic activities toward the activated HSCs and suppressed TNF-α production in RAW264.7 macrophages. These compounds may be useful candidates for developing therapeutic agents for the prevention and treatment of hepatic fibrosis.

The interplay of the Notch signaling in hepatic stellate cells and macrophages determines the fate of liver fibrogenesis

Hepatic stellate cells (HSCs) known as "master producers" and macrophages as "master regulators", are the key cell types that strongly contribute to the progression of liver fibrosis. Since Notch signaling regulates multiple cellular processes, we aimed to study the role of Notch signaling in HSCs differentiation and macrophages polarization and to evaluate its implication in liver fibrogenesis. Notch pathway components were found to be significantly upregulated in TGFβ-activated HSCs, inflammatory M1 macrophages, and in mouse and human fibrotic livers. Interestingly, inhibition of Notch using a selective γ-secretase inhibitor, Avagacestat, significantly inhibited TGFβ-induced HSC activation and contractility, and suppressed M1 macrophages. Additionally, Avagacestat inhibited M1 driven-fibroblasts activation and fibroblasts-driven M1 polarization (nitric oxide release) in fibroblasts and macrophages co-culture, and conditioned medium studies. In vivo, post-disease treatment with Avagacestat significantly attenuated fibrogenesis in CCl4-induced liver fibrosis mouse model. These effects were attributed to the reduction in HSCs activation, and inhibition of inflammatory M1 macrophages and upregulation of suppressive M2 macrophages. These findings suggest that Notch signaling plays a crucial role in HSC activation and M1/M2 polarization of macrophages in liver fibrosis. These results provide new insights for the development of novel therapies against liver fibrosis through modulation of Notch signaling.

Ginkgo biloba extract mitigates liver fibrosis and apoptosis by regulating p38 MAPK, NF-κB/IκBα, and Bcl-2/Bax signaling

Background

Liver fibrosis is the consequence of diverse liver injuries and can eventually develop into liver cirrhosis. Ginkgo biloba extract (GBE) is an extract from dried ginkgo leaves that has many pharmacological effects because of its various ingredients and has been shown to be hepatoprotective.

Purpose and methods

Aimed to investigate the underlying protective mechanisms of GBE on carbon tetrachloride (CCl₄)-induced liver fibrosis in rats. Male Sprague Dawley rats were randomly divided into four groups: control group (C), model group (M), low-dose group (L), and high-dose group (H). Liver fibrosis was induced by CCl₄ groups M, L, and H: group C was administered saline. In addition, GBE at different doses was used to treat groups L and H.

Results

The results of hematoxylin and eosin staining, Masson’s trichrome staining, a liver function index, and a liver fibrosis index showed that GBE application noticeably mitigated fibrosis and improved the function of the liver. The western blotting and immunohistochemistry analyses indicated that GBE reduced liver fibrosis not only by inhibiting p38 MAPK and NF-κBp65 via inhibition of IκBα degradation but also by inhibiting hepatocyte apoptosis via downregulation of Bax, upregulation of Bcl-2, and subsequent inhibition of caspase-3 activation. Inflammation-associated factors and hepatic stellate cell (HSC)-activation markers further demonstrated that GBE could effectively inhibit HSC activation and inflammation as a result of its regulation of p38 MAPK and nuclear factor-kappa B/IκBα signaling.

Conclusion

Our findings indicated a novel role for GBE in the treatment of liver fibrosis. The potential mechanisms may be associated with the following signaling pathways: 1) the p38 MAPK and nuclear factor-kappa B/IκBα signaling pathways (inhibiting inflammation and HSCs activation) and 2) the Bcl-2/Bax signaling pathway (inhibiting the apoptosis of hepatocytes).

Activation of Slit2-Robo1 signaling promotes liver fibrosis

BACKGROUND & AIMS

The secretory protein Slit2 and its receptor Robo1 are believed to regulate cell growth and migration. Here, we aimed to determine whether Slit2-Robo1 signaling mediates the pathogenesis of liver fibrosis.

METHODS

Serum levels of Slit2 in patients with liver fibrosis were determined by ELISA. Liver fibrosis was induced in wild-type (WT), Slit2 transgenic (Slit2-Tg) and Robo1(+/-)Robo2(+/-) double heterozygotes (Robo1/2(+/-)) mice by carbon tetrachloride (CCl4). The functional contributions of Slit2-Robo1 signaling in liver fibrosis and activation of hepatic stellate cells (HSCs) were investigated using primary mouse HSCs and human HSC cell line LX-2.

RESULTS

Significantly increased serum Slit2 levels and hepatic expression of Slit2 and Robo1 were observed in patients with liver fibrosis. Compared to WT mice, Slit2-Tg mice were much more vulnerable to CCl4-induced liver injury and more readily develop liver fibrosis. Development of hepatic fibrosis in Slit2-Tg mice was associated with a stronger hepatic expression of collagen I and α-smooth muscle actin (α-SMA). However, liver injury and hepatic expression of collagen I and α-SMA were attenuated in CCl4-treated Robo1/2(+/-) mice in response to CCl4 exposure. In vitro, Robo1 neutralizing antibody R5 and Robo1 siRNA downregulated phosphorylation of Smad2, Smad3, PI3K, and AKT in HSCs independent of TGF-β1. R5 and Robo1 siRNA also inhibited the expression of α-SMA by HSCs. Finally, the protective effect of R5 on the CCl4-induced liver injury and fibrosis was further verified in mice.

CONCLUSIONS

Slit2-Robo1 signaling promotes liver injury and fibrosis through activation of HSCs.

Inhibition of IRF3 expression reduces TGF-β1-induced proliferation of hepatic stellate cells

Therapeutic management of liver fibrosis remains an unresolved clinical problem. Activation of hepatic stellate cell (HSC) is a pivotal event in the progression of liver fibrosis. Recent reports have showed that inhibition of activated HSC proliferation contributes to the reversal of liver fibrosis. Interferon regulatory factor 3 (IRF3), one member of the interferon regulatory factor (IRF) family, is recently proven to be a critical modulator in cardiac fibrosis. And accumulating evidence demonstrated that IRF3 plays a crucial role in liver diseases, such as hepatic steatosis, liver inflammation, and alcoholic liver injury. However, the understanding of the function of IRF3 in liver fibrosis remains limited. Our results identified the role of IRF3 in regulating human HSC (LX-2 cell) cell proliferation and apoptosis. The present study indicated that the expression of IRF3 was significantly increased in HSCs in response to TGF-β1 stimulation. Moreover, a stable and unlimited source of human HSC, the LX-2 cell line, transfected with IRF3-siRNA significantly decreases the expression level of type I collagen (Col1a1) and α-smooth muscle actin (α-SMA) in activated LX-2 cells. On the contrary, overexpression of IRF3 gives rise to an upregulation of Col1a1 and α-SMA in LX-2 cells, and further promoted HSC proliferation. Moreover, the inhibition of IRF3 significantly suppressed TGF-β1-induced HSC proliferation and increased its apoptosis. Of note, the present study indicated IRF3 may regulate LX-2 cell proliferation by via AKT signaling pathway. In summary, these observations suggest IRF3 may function as a novel regulator to modulate TGF-β1-induced LX-2 proliferation, at least in part, via AKT signaling pathway.

Characterization and sub-cellular localization of GalNAc-binding proteins isolated from human hepatic stellate cells

Although the expression levels of total GalNAc-binding proteins (GNBPs) were up-regulated significantly in human hepatic stellate cells (HSCs) activated with transforming growth factor-β1(TGF-β1), yet little is known about the precise types, distribution and sub-cellular localization of the GNBPs in HSCs. Here, 264 GNBPs from the activated HSCs and 257 GNBPs from the quiescent HSCs were identified and annotated. A total of 46 GNBPs were estimated to be significantly up-regulated and 40 GNBPs were estimated to be significantly down-regulated in the activated HSCs. For example, the GNBPs (i.e. BTF3, COX17, and ATP5A1) responsible for the regulation of protein binding were up-regulated, and those (i.e. FAM114A1, ENO3, and TKT) responsible for the regulation of protein binding were down-regulated in the activated HSCs. The motifs of the isolated GNBPs showed that Proline residue had the maximum preference in consensus sequences. The western blotting showed the expression levels of COX17, and PRMT1 were significantly up-regulated, while, the expression level of CLIC1(B5) was down-regulated in the activated HSCs and liver cirrhosis tissues. Moreover, the GNBPs were sub-localized in the Golgi apparatus of HSCs. In conclusion, the precision alteration of the GNBPs referred to pathological changes in liver fibrosis/cirrhosis may provide useful information to find new molecular mechanism of HSC activation and discover the biomarkers for diagnosis of liver fibrosis/cirrhosis as well as development of new anti-fibrotic strategies.

NS5ATP9 suppresses activation of human hepatic stellate cells, possibly via inhibition of Smad3/phosphorylated-Smad3 expression

Activation of hepatic stellate cell (HSC) is the central event in liver fibrosis. NS5ATP9 is related to many malignant tumors, but little is known about its function in HSC activation. The aim of this study is to investigate the role of NS5ATP9 in HSC activation in vitro. Genes related to liver fibrosis were detected after NS5ATP9 overexpression or silencing with or without transforming growth factor (TGF)-β1 stimulation in the human HSCs by real-time polymerase chain reaction and western blotting. Cell proliferation, migration, and apoptosis were tested, and the mechanisms underlying the effect of NS5ATP9 on HSC activation were studied. We showed that NS5ATP9 suppressed HSC activation and collagen production, with or without TGF-β1 induction. Also, NS5ATP9 inhibited cell proliferation and migration and promoted apoptosis. Furthermore, NS5ATP9 reduced basal and TGF-β1-mediated Smad3/phosphorylated-Smad3 expression. The existence of a physical complex between NS5ATP9 and Smad3 was illustrated. NS5ATP9 suppresses HSC activation, extracellular matrix production, and promotes apoptosis, in part through reducing Smad3/phosphorylated-Smad3 expression.

NIM811 downregulates transforming growth factor‑β signal transduction in vivo and in vitro

Liver fibrosis is the common histological feature of a number of chronic liver diseases, and leads to cirrhosis and hepatocellular carcinoma (HCC). It has been demonstrated that N‑methyl‑4‑isoleucine cyclosporine (NIM811) attenuates CCl4‑induced liver fibrosis and inflammation in rats. The present study investigated whether NIM811 downregulated transforming growth factor (TGF)‑β signaling in rats with CCl4‑induced liver fibrosis and in HSC‑T6 cells. Liver tissues were obtained from rats with CCl4‑induced liver fibrosis, with or without NIM811 treatment. HSC‑T6 cells were cultured with or without NIM811 for 18 h under serum‑free conditions. Expression of collagen I, α‑smooth muscle actin (α‑SMA), TGF‑β1, TGF‑β receptor I (TβR‑I) and TGF‑β pathway downstream signaling molecules were measured by reverse transcription‑quantitative polymerase chain reaction and/or western blotting. Collagen I and TGF‑β1 content in the cell supernatant was measured by ELISA. NIM811 profoundly inhibited collagen I, α‑SMA, TGF‑β1 and TβR‑I expression in the liver of CCl4‑treated rats. Phosphorylation of Smad2, 3 and 1/5/8 was decreased in the liver of NIM811‑treated groups, accompanied by increased In addition, Smad7 expression compared with the CCl4‑treated rats. NIM811 inhibited collagen I, TGF‑β1 and TβR‑I expression in HSC‑T6 cells. Smad1 mRNA and phospho‑Smad1/5/8 protein levels decreased following NIM811 treatment, accompanied by increased Smad7 expression in HSC‑T6 cells compared with normal controls. Furthermore, NIM811 also inhibited collagen I mRNA expression in the liver of rats with CCl4‑induced liver fibrosis and in HSC‑T6 cells. The results suggest that the antifibrotic effect of NIM811 was due to the inhibition of TGF‑β1 and its downstream signaling molecules.

The Therapeutic Promise of Mesenchymal Stem Cells for Liver Restoration

Hepatocyte transplantation aims to provide a functional substitution of liver tissue lost due to trauma or toxins. Chronic liver diseases are associated with inflammation, deterioration of tissue homeostasis, and deprivation of metabolic capacity. Recent advances in liver biology have focused on the pro-regenerative features of mesenchymal stem cells (MSCs). We argue that MSCs represent an attractive therapeutic option to treat liver disease. Indeed, their pleiotropic actions include the modulation of immune reactions, the stimulation of cell proliferation, and the attenuation of cell death responses. These characteristics are highly warranted add-ons to their capacity for hepatocyte differentiation. Undoubtedly, the elucidation of the regenerative mechanisms of MSCs in different liver diseases will promote their versatile and disease-specific therapeutic use.

Protective effect of gastrodin on bile duct ligation-induced hepatic fibrosis in rats

Gastrodin has been showed to possess many beneficial physiological functions, including protection against inflammation and oxidation and apoptosis. Studies showed inflammation and oxidation play important roles in producing liver damage and initiating hepatic fibrogenesis. However, it has not been reported whether gastrodin has a protective effect against hepatic fibrosis or not. This is first ever made attempts to test gastrodin against liver fibrosis in bile duct ligation (BDL) rats. The aim of the present study is to evaluate the effect of gastrodin on BDL-induced hepatic fibrosis in rats. BDL rats were divided into two groups, BDL alone group, and BDL-gastrodin group treated with gastrodin (5 mg/ml in drinking water). The effects of gastrodin on BDL-induced hepatic injury and fibrosis in rats were estimated by assessing serum, urine, bile and liver tissue biochemistry followed by liver histopathology (using hematoxylin & eosin and sirius red stain) and hydroxyproline content measurement. The results showed that gastrodin treatment significantly reduced collagen content, bile duct proliferation and parenchymal necrosis after BDL. The serum alanine aminotransferase (ALT) and serum aspartate aminotransferase (AST) decreased with gastrodin treatment by 15.1 and 23.6 percent respectively in comparison to BDL group did not receive gastrodin. Gastrodin also significantly increased the level of serum high density lipoprotein (HDL) by 62.5 percent and down-regulated the elevated urine total bilirubin (TBIL) by 56.5 percent, but had no effect on total bile acid (TBA) in serum, bile and liver tissues. The immunohistochemical assay showed gastrodin remarkably reduced the expressions of CD68 and NF-κB in BDL rats. Hepatic SOD levels, depressed by BDL, were also increased by gastrodin by 8.4 percent. In addition, the increases of hepatic MDA and NO levels in BDL rats were attenuated by gastrodin by 31.3 and 38.7 percent separately. Our results indicate that gastrodin significantly attenuated the severity of BDL-induced hepatic injury and fibrosis by attenuating oxidative stress and inflammation. Taken together, these findings suggest that gastrodin might be an effective antifibrotic drug in cholestatic liver disease.

Silent information regulator 1 (SIRT1) ameliorates liver fibrosis via promoting activated stellate cell apoptosis and reversion

SIRT1 (silent information regulator 1), a conserved NAD+-dependent histone deacetylase, is closely related with various biological processes. Moreover, the important role of SIRT1 in alcoholic liver disease, nonalcoholic fatty liver and HCC had been widely reported. Recently, a novel role of SIRT1 was uncovered in organ fibrosis diseases. Here, we investigated the inhibitory effect of SIRT1 in liver fibrogenesis. SIRT1 protein was dramatically decreased in CCl4-treated mice livers. Stimulation of LX-2 cells with TGF-β1 also resulted in a significant suppression of SIRT1 protein. Nevertheless, TGF-β1-induced LX-2 cell activation was inhibited by SIRT1 plasmid, and this was accompanied by up-regulation of cell apoptosis-related proteins. Overexpression of SIRT1 also attenuated TGF-β1-induced expression of myofibroblast markers α-SMA and COL1a. However, the important characteristic of the recovery of liver fibrosis is not only the apoptosis of activated stellate cells but also the reversal of the myofibroblast-like phenotype to a quiescent-like phenotype. Restoration of SIRT1 protein was observed in the in vivo spontaneously liver fibrosis reversion model and in vitro MDI (isobutylmethylxanthine, dexamethasone, and insulin)-induced reversed stellate cells, and forced expression of SIRT1 also promoted the reversal of activated stellate cells. Furthermore, lncRNA MALAT1 (metastasis-associated lung adenocarcinoma transcript 1) was increased in liver fibrosis. RNAi-mediated suppression of MALAT1 resulted in a decrease of myofibroblast markers and restoration of SIRT1 protein. These observations suggested that SIRT1 contributed to apoptosis and reversion of activated LX-2 cells and SIRT1 might be regulated by MALAT1 in liver fibrosis. Therefore, SIRT1 could be considered as a valuable therapeutic target for translational studies of liver fibrosis.

Comparison of magnetic resonance elastography and diffusion-weighted imaging for staging hepatic fibrosis

Background:

To compare the diagnostic values of magnetic resonance elastography (MRE) and diffusion-weighted imaging (DWI) in staging hepatic fibrosis (HF) in an animal model.

Methods:

This study consisted of 44 rabbits served as HF group and 9 normal rabbits. HF group was divided into two subgroups: Group A (n = 32) and Group B (n = 12). Rabbits in Group B were served as a complementary group when rabbits in Group A suddenly died during the study. Rabbits from control and Group A underwent abdominal MR imaging (MRI), MRE, and DWI. In Group A, random eight rabbits underwent MRI examinations at 4, 5, 6, 10 weeks after carbon tetrachloride oil subcutaneous injection. Liver stiffness (LS) and apparent diffusion coefficient (ADC) values of liver parenchyma were measured. The diagnostic performance of MRE and DWI for staging HF was compared using the receiver operating characteristic curve analysis on the basis of the histopathological analysis of HF.

Results:

Significant differences of LS and DWI values were present among HF stages (P < 0.005). The LS values measured on MRE (r = 0.838, P < 0.001) were more strongly correlated with the HF stages than with ADC values (r = −0.527, P < 0.001). The area under the receiver operating characteristic curve values of LS were significantly larger than those of DWI were for discriminating two stages of HF (0.979 vs. 0.712 for ≥ S1, 0.922 vs. 0.699 for ≥ S2). MRE showed higher specificity for predicting all stages of HF compared to DWI.

Conclusions:

MRE more strongly correlated with the HF stages than DWI and is more specific in predicting all HF stages.

Bone marrow-derived mesenchymal stem cells inhibit the proliferation of hepatic stellate cells by inhibiting the transforming growth factor β pathway

Bone marrow-derived mesenchymal stem cells (BM-MSCs) are considered to be a potential therapy for end-stage liver disease. However, the therapeutic mechanism of BM-MSCs remains unclear. The aim of the current study was to investigate the role of paracrine signaling in BM-MSCs in liver cirrhosis in vitro. Human BM-MSCs and hepatic stellate cells (HSCs) were cultured using a vertical double cell co-culture system. Groups were divided into HSCs alone (control group) and the co-culture system of BM-MSCs with HSCs (experimental group). HSC morphology was observed by inverted phase contrast microscopy. The proliferative capacity of HSCs was measured with the MTT assay and flow cytometry. Hoechst staining was performed to examine the apoptosis of HSCs. Transforming growth factor (TGF)-β1 and Smad7 mRNA expression were detected by reverse transcription-quantitative polymerase chain reaction and western blotting. BM-MSCs did not inhibit the proliferation of HSCs at 24 h, however significantly inhibited the proliferation of HSCs at 48 and 72 h. BM-MSCs additionally induced the apoptosis of HSCs at 48 h. The concentration of TGF-β1 in the supernatant at 24 h and 48 h in the co-cultured system was observed to be significantly lower than in the control group (P<0.05). The level of TGF-β1 mRNA in the experimental group at 48 h was significantly lower than the control group, however Smad7 mRNA levels were significantly greater than in the control group. Additionally, TGF-β1 protein levels were significantly lower than in the control group, however levels of Smad7 were greater than the control group. It was concluded that BM-MSCs are able to inhibit the proliferation and promote the apoptosis of HSCs. In addition, the mechanism may be associated with inhibition of the TGF-β1/Smad pathway in HSCs.

M1 Muscarinic Receptor Deficiency Attenuates Azoxymethane-Induced Chronic Liver Injury in Mice

Cholinergic nervous system regulates liver injury. However, the role of M1 muscarinic receptors (M1R) in modulating chronic liver injury is uncertain. To address this gap in knowledge we treated M1R-deficient and WT mice with azoxymethane (AOM) for six weeks and assessed liver injury responses 14 weeks after the last dose of AOM. Compared to AOM-treated WT mice, M1R-deficient mice had attenuated liver nodularity, fibrosis and ductular proliferation, α-SMA staining, and expression of α1 collagen, Tgfβ-R, Pdgf-R, Mmp-2, Timp-1 and Timp-2. In hepatocytes, these findings were associated with reductions of cleaved caspase-3 staining and Tnf-α expression. In response to AOM treatment, M1R-deficient mice mounted a vigorous anti-oxidant response by upregulating Gclc and Nqo1 expression, and attenuating peroxynitrite generation. M1R-deficient mouse livers had increased expression of Trail-R2, a promotor of stellate cell apoptosis; dual staining for TUNNEL and α-SMA revealed increased stellate cells apoptosis in livers from M1R-deficient mice compared to those from WT. Finally, pharmacological inhibition of M1R reduced H₂O₂-induced hepatocyte apoptosis in vitro. These results indicate that following liver injury, anti-oxidant response in M1R-deficient mice attenuates hepatocyte apoptosis and reduces stellate cell activation, thereby diminishing fibrosis. Therefore, targeting M1R expression and activation in chronic liver injury may provide therapeutic benefit.

Alteration and localization of glycan-binding proteins in human hepatic stellate cells during liver fibrosis

Glycan-binding proteins (GBPs) play an important role in cell adhesion, bacterial/viral infection, and cellular signaling pathways. However, little is known about the precision alteration of GBPs referred to pathological changes in hepatic stellate cells (HSCs) during liver fibrosis. Here, the carbohydrate microarrays were used to probe the alteration of GBPs in the activated HSCs and quiescent HSCs. As a result, 12 carbohydrates (e.g. Gal, GalNAc, and Man-9Glycan) showed increased signal, while seven carbohydrates (e.g. NeuAc, Lac, and GlcNAc-O-Ser) showed decreased signal in activated HSCs. Three carbohydrates (Gal, GalNAc, and NeuAc) were selected and subsequently used to validate the results of the carbohydrate microarrays as well as assess the distribution and localization of their binding proteins in HSCs and liver tissues by cy/histochemistry; the results showed that GBPs mainly distributed in the cytoplasma membrane and perinuclear region of cytoplasm. The immunocytochemistry was further used to verify some GBPs really exist in Golgi apparatus of the cells. The precision alteration and localization of GBPs referred to pathological changes in HSCs may provide pivotal information to help understand the biological functions of glycans how to exert through their recognition by a wide variety of GBPs. This study could lead to the development of new anti-fibrotic strategies.

Cytoglobin expression in the hepatic stellate cell line HSC-T6 is regulated by extracellular matrix proteins dependent on FAK-signalling

BACKGROUND

Fibrosis is a physiological response to cellular injury in the liver and is mediated by the activation of hepatic stellate cells resulting in the replacement of hepatocytes with extracellular matrix comprised principally of collagen 1 to form a hepatic scar. Although the novel hexaco-ordinated globin cytoglobin was identified in activated hepatic stellate cells more than 10 years ago, its role in stellate cell biology and liver fibrosis remains enigmatic.

RESULTS

In the current study, we investigated the role of different extracellular matrix proteins in stellate cell proliferation, activation (alpha smooth muscle actin expression and retinoic acid uptake) and cytoglobin expression. Our results demonstrate that cytoglobin expression is correlated with a more quiescent phenotype of stellate cells in culture and that cytoglobin is regulated by the extracellular matrix through integrin signalling dependent on activation of focal adhesion kinase.

CONCLUSIONS

Although further studies are required, we provide evidence that cytoglobin is a negative regulator of stellate cell activation and therefore may represent a novel target for anti-fibrotic treatments in the future.

MicroRNA-130a and -130b enhance activation of hepatic stellate cells by suppressing PPARγ expression: A rat fibrosis model study

Hepatic stellate cells (HSCs) are the primary sources of extracellular matrix (ECM) in normal and fibrotic liver. Peroxisome proliferator-activated receptor gamma (PPARγ) maintains HSCs in a quiescent state, and its downregulation induces HSC activation. MicroRNAs (miRNAs) can induce PPARγ mRNA degradation, but the mechanism by which miRNAs regulate PPARγ in rat HSCs is unclear. This study aimed to investigate some miRNAs which putatively bind to the 3'-untranslated region (3'-UTR) of PPARγ mRNA, and increase expression of ECM genes in rat HSCs. In carbon tetrachloride injection (CCl4) and common bile duct ligation (CBDL) liver fibrosis models, miRNAs miR-130a, miR-130b, miR-301a, miR-27b and miR-340 levels were found to be increased and PPARγ expression decreased. Overexpression of miR-130a and miR-130b enhanced cell proliferation by involving Runx3. MiR-130a and miR-130b decreased PPARγ expression by targeting the 3'-UTR of PPARγ mRNA in rat HSC-T6 cells. Transforming growth factor-β1 (TGF-β1) may mediate miR-130a and miR-130b overexpression, PPARγ downregulation, and ECM genes overexpression in cell culture. These findings suggest that miR-130a and miR-130b are involved in downregulation of PPARγ in liver fibrosis.

Anti-fibrotic Role of miR-214 in Thioacetamide-induced Liver Cirrhosis in Rats

An increasing number of studies have focused on the role of microRNAs in liver fibrosis/cirrhosis. miR-214 has recently attracted more attention as a fibrosis-related factor; however, the molecular mechanisms in hepatic fibrogenesis remain largely unknown. Here, we investigate the pathological role of miR-214 during progression of liver cirrhosis in rats. Rats were injected intraperitoneally with thioacetamide at a dose of 100 mg/kg body weight, twice a week. The liver was collected at post first injection weeks 5, 10, 15, and 20. Hepatic expression of miR-214 was analyzed by real-time polymerase chain reaction, in situ hybridization, and laser microdissection. The effects of miR-214 overexpression were investigated by in vitro transfection using fibroblastic MT-9 cells. miR-214 was highly upregulated in the fibrotic area in parallel with the cirrhosis progression. miR-214 overexpression in MT-9 cells under transforming growth factor-β1 stimulation resulted in decreased cell number and increased expression of cleaved caspase 3 and decreased expression of α-smooth muscle actin, suggesting that miR-214 induces apoptosis and inhibits myofibroblast differentiation in fibroblastic cells under stimulation of fibrogenic factors. These data indicate an anti-fibrotic role of miR-214 in chemically induced liver fibrosis/cirrhosis.

Hepatic MR Elastography: Clinical Performance in a Series of 1377 Consecutive Examinations

PURPOSE

To assess the technical success rate and diagnostic performance of liver magnetic resonance (MR) elastography.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board with patient informed consent. A total of 1377 consecutive MR elastography examinations performed between 2007 and 2010 in 1287 patients for clinical indications were included. Medical records were used to retrieve liver stiffness as assessed with MR elastography, histologic analysis, blood work, and other liver disease-related information. Nonparametric Kruskal-Wallis tests and analysis of covariance methods were used to evaluate the diagnostic values and relationships of the collected data.

RESULTS

Hepatic MR elastography had a success rate of 94.4% (1300 of 1377 cases) and yielded reproducible measurements (r = 0.9716, P < .0001) in the study cohort, with a complex patient profile and multiple interpreters. Body mass index had no significant effect on success rate (P = .2). In 289 patients who underwent liver biopsy within 1 year of the MR elastography date, mean liver stiffness as assessed with MR elastography was significantly higher in patients with advanced fibrosis (stages F3, F4) than in those with mild to moderate fibrosis (stages F0, F1, F2) (5.93 kPa ± 2.31 [standard deviation] vs 3.35 kPa ± 1.44, P < .0001). Liver stiffness is associated with many factors other than fibrosis extent, including cause of fibrosis (viral hepatitis C vs nonalcoholic fatty liver disease, P = .025), inflammation (severe vs mild to moderate, P = .03), and hepatic metabolic and synthetic function (no fibrosis vs intermediate fibrosis, P ≤ .01).

CONCLUSION

In a general clinical practice environment, hepatic MR elastography is a robust imaging method with a high success rate in a broad spectrum of patients. It also shows the complex association between liver stiffness and hepatic pathophysiology.

Efficacy and mechanism of tanshinone IIA liquid nanoparticles in preventing experimental postoperative peritoneal adhesions in vivo and in vitro

Up to 90% of patients develop adhesion following laparotomy. Upregulating fibrinolysis within the peritoneum reduces adhesions. Tanshinone IIA (Tan IIA) promotes fibrinolysis in hepatic fibrosis and the cardiovascular system and may play a role in preventing adhesions. We report preparation and characterization of liquid nanoparticles of Tan IIA for intravenous administration and investigate its feasibility in clinical practice. Tan IIA liquid nanoparticles (Tan IIA-NPs) were prepared using the emulsion/solvent evaporation method. Adhesions were induced in Sprague–Dawley rats by injuring the parietal peritoneum and cecum, followed by intravenous administration of various Tan IIA-NP dosages. The adhesion scores for each group were collected 7 days after the initial laparotomy. The activity of tissue-type plasminogen activator (tPA) was measured from the peritoneal lavage fluid. The messenger RNA and protein expression levels of plasminogen activator inhibitor-1 (PAI-1) were measured by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. TGF-β1 and collagen I expressions were measured immunohistochemically in the ischemic tissues. The effects of Tan IIA-NPs and free-Tan IIA on tPA and PAI-1 were measured in vitro in TGF-β1-induced HMrSV5 cells. Tan IIA-NPs exhibited small particle size, high encapsulation efficiency, good stability for storage, and safety for intravenous administration. Tan IIA-NPs were effective in preventing adhesion. Tan IIA-NPs increased tPA activity in peritoneal lavage fluid, and tPA mRNA and protein expression, and decreased PAI-1 mRNA and protein expression in the ischemic tissues. Moreover, Tan IIA-NPs decreased TGF-β1 and collagen I expressions in the ischemic tissues. Tan IIA-NPs administered via tail veins upregulated fibrinolysis in the peritoneum. In vitro studies showed that these effects may be mediated by the TGF-β signal pathway.

Strategies to prevent and reverse liver fibrosis in humans and laboratory animals

Liver fibrosis results from chronic damage to the liver in conjunction with various pathways and is mediated by a complex microenvironment. Based on clinical observations, it is now evident that fibrosis is a dynamic, bidirectional process with an inherent capacity for recovery and remodeling. The major mechanisms involved in liver fibrosis include the repetitive injury of hepatocytes, the activation of the inflammatory response after injury stimulation, and the activation and proliferation of hepatic stellate cells (HSCs), which represents the major extracellular matrix (ECM)-producing cells, stimulated by hepatocyte injury and inflammation. The microenvironment in the liver is synergistically regulated abnormal ECM deposition, scar formation, angiogenesis, and fibrogenesis. Moreover, recent studies have clarified novel mechanism in fibrosis such as epigenetic regulation of HSCs, the leptin and PPARγ pathways, the coagulation system, and even autophagy. Uncovering the mechanisms of liver fibrogenesis provides a basis to develop potential therapies to reverse and treat the fibrotic response, thereby improving the outcomes of patients with chronic liver disease. Although both scientific and clinical challenges remain, emerging studies attempt to reveal the ideal anti-fibrotic drug that could be easily delivered to the liver with high specificity and low toxicity. This review highlights the mechanisms, including novel pathways underlying fibrogenesis that may be translated into preventive and treatment strategies, reviews both current and novel agents that target specific pathways or multiple targets, and discusses novel drug delivery systems such as nanotechnology that can be applied in the treatment of liver fibrosis. In addition, we also discuss some current treatment strategies that are being applied in animal models and in clinical trials.

The anti-fibrotic effects of epigallocatechin-3-gallate in bile duct-ligated cholestatic rats and human hepatic stellate LX-2 cells are mediated by the PI3K/Akt/Smad pathway

AIM

(-)-Epigallocatechin-3-gallate (EGCG) is one of the most abundant polyphenols in green tea with strong antioxidant activity and various therapeutic effects. In this study, we investigated the anti-fibrotic effects of EGCG and underlying mechanisms in bile duct-ligated (BDL) rats and a liver fibrosis model in vitro.

METHODS

BDL rats were treated with EGCG (25 mg·kg(-1)·d(-1), po) for 14 d, and then the serum, bile and liver samples were collected. Liver fibrosis was assessed by serum, urine and bile biochemistry analyses and morphological studies of liver tissues. TGF-β1-stimulated human hepatic stellate LX-2 cells were used as a liver fibrosis model in vitro. The expression of liver fibrogenic genes and signaling proteins in the PI3K/Akt/Smad pathway was examined using Western blotting and/or real-time PCR.

RESULTS

In BDL rats, EGCG treatment significantly ameliorates liver necrosis, inflammation and fibrosis, and suppressed expression of the genes associated with liver inflammation and fibrogenesis, including TNF-α, IL-1β, TGF-β1, MMP-9, α-SMA, and COL1A1. In LX-2 cells, application of EGCG (10, 25 μmol/L) dose-dependently suppressed TGF-β1-stimulated expression of COL1A1, MMP-2, MMP-9, TGF-β1, TIMP1, and α-SMA. Furthermore, EGCG significantly suppressed the phosphorylation of Smad2/3 and Akt in the livers of BDL rats and in TGF-β1-stimulated LX-2 cells. Application of LY294002, a specific inhibitor of PI3K, produced similar effects as EGCG did in TGF-β1-stimulated LX-2 cells, but co-application of EGCG and LY294002 did not produce additive effects.

CONCLUSION

EGCG exerts anti-fibrotic effects in BDL rats and TGF-β1-stimulated LX-2 cells in vitro via inhibiting the PI3K/Akt/Smad pathway.

K⁺-channel inhibition reduces portal perfusion pressure in fibrotic rats and fibrosis associated characteristics of hepatic stellate cells

BACKGROUND & AIMS

In liver fibrosis, activated hepatic stellate cells (HSC) secrete excess extracellular matrix, thus, represent key targets for antifibrotic treatment strategies. Intermediate-conductance Ca(2) (+) -activated K(+) -channels (KCa3.1) are expressed in non-excitable tissues affecting proliferation, migration and vascular resistance rendering KCa3.1 potential targets in liver fibrosis. So far, no information about KCa3.1 expression and their role in HSC exists. Aim was to quantify the KCa3.1 expression in HSC depending on HSC activation and investigation of antifibrotic properties of the specific KCa3.1 inhibitor TRAM-34 in vitro and in vivo.

METHODS

KCa3.1 expression and functionality were studied in TGF-β1-activated HSC by quantitative real time PCR, western-blot and patch-clamp analysis respectively. Effects of TRAM-34 on HSC proliferation, cell cycle and fibrosis-related gene expression were assessed by [(3) H]-thymidine incorporation, FACS-analysis and RT-PCR respectively. In vivo, vascular resistance and KCa3.1 gene and protein expression were determined in bile duct ligated rats by in situ liver perfusion, Taqman PCR and immunohistochemistry respectively.

RESULTS

Fibrotic tissues and TGF-β1-activated HSC exhibited higher KCa3.1-expressions than normal tissue and untreated cells. KCa3.1 inhibition with TRAM-34 reduced HSC proliferation by induction of cell cycle arrest and reduced TGF-β1-induced gene expression of collagen I, alpha-smooth muscle actin and TGF-β1 itself. Furthermore, TRAM-34 blocked TGF-β1-induced activation of TGF-β signalling in HSC. In vivo, TRAM-34 reduced the thromboxane agonist-induced portal perfusion pressure.

CONCLUSION

Inhibition of KCa3.1 with TRAM-34 downregulates fibrosis-associated gene expression in vitro, and reduces portal perfusion pressure in vivo. Thus, KCa3.1 may represent novel targets for the treatment of liver fibrosis.

Staging of liver fibrosis or cirrhosis: The role of hepatic venous pressure gradient measurement

Liver fibrosis is a common histological change of chronic liver injury and it is closely related with portal hypertension which is hemodynamic complication of chronic liver disease. Currently, liver fibrosis has been known as a reversible dynamic process in previous literatures. Although liver biopsy is a gold standard for assessing the stage of liver fibrosis, it may not completely represent the stage of liver fibrosis because of sampling error or semi-quantative measurement. Recent evidences suggested that histologic, clinical, hemodynamic, and biologic features are closely associated in patients with chronic liver disease. Hepatic venous pressure gradient (HVPG) measurement has been known as a modality to evaluate the portal pressure. The HVPG measurement has been used clinically for fibrosis diagnosis, risk stratification, preoperative screening for liver resection, monitoring the efficacy of medical treatments, and assessing the prognosis of liver fibrosis. Therefore, the HVPG measurement can be used to monitor areas the chronic liver disease but also other important areas of chronic liver disease.

Quantitative imaging: quantification of liver shape on CT using the statistical shape model to evaluate hepatic fibrosis

RATIONALE AND OBJECTIVES

To investigate the usefulness of the statistical shape model (SSM) for the quantification of liver shape to evaluate hepatic fibrosis.

MATERIALS AND METHODS

Ninety-one subjects (45 men and 46 women; age range, 20-75 years) were included in this retrospective study: 54 potential liver donors and 37 patients with chronic liver disease. The subjects were classified histopathologically according to the fibrosis stage as follows: F0 (n = 55); F1 (n = 6); F2 (3); F3 (n = 1); and F4 (n = 26). Each subject underwent contrast-enhanced computed tomography (CT) using a 64-channel scanner (0.625-mm slice thickness). An abdominal radiologist manually traced the liver boundaries on every CT section using an image workstation; the boundaries were used for subsequent analyses. An SSM was constructed by the principal component analysis of the subject data set, which defined a parametric model of the liver shapes. The shape parameters were calculated by fitting SSM to the segmented liver shape of each subject and were used for the training of a linear support vector regression (SVR), which classifies the liver fibrosis stage to maximize the area under the receiver operating characteristic curve (AUC). SSM/SVR models were constructed and were validated in a leave-one-out manner. The performance of our technique was compared to those of two previously reported types of caudate-right lobe ratios (C/RL-m and C/RL-r).

RESULTS

In our SSM/SVR models, the AUC values for the classification of liver fibrosis were 0.96 (F0 vs. F1-4), 0.95 (F0-1 vs. F2-4), 0.96 (F0-2 vs. F3-4), and 0.95 (F0-3 vs. F4). These values were significantly superior to AUC values using the C/RL-m or C/RL-r ratios (P < .005).

CONCLUSIONS

SSM was useful for estimating the stage of hepatic fibrosis by quantifying liver shape.

Deficiency of BPOZ2 Decreases Liver Fibrosis After Chronic Carbon Tetrachloride Administration in Mice

Bood POZ containing gene type 2 (BPOZ2), a Broad-Complex, Tramtrack, and Bric a brac domain containing protein, is an adaptor protein for the E3 ubiquitin ligase scaffold protein CUL3. It plays an important role in acute carbon tetrachloride (CCl4)-induced liver injury and regeneration in mice. In this study, we investigated the role of BPOZ2 in the process of liver fibrosis induced by chronic CCl4 treatment. The results indicate that BPOZ2 deficiency decreases sustained activation of hepatic stellate cells, attenuates collagen αI(I) and tissue inhibitor of matrix metalloprotease 1 expression, and decreases liver fibrosis after repeated CCl4 administration. These findings suggest BPOZ2 as a new therapeutic target for the prevention and treatment of hepatic fibrosis in chronic liver disease.

Hepatic stellate cells and liver fibrosis

Hepatic stellate cells are resident perisinusoidal cells distributed throughout the liver, with a remarkable range of functions in normal and injured liver. Derived embryologically from septum transversum mesenchyme, their precursors include submesothelial cells that invade the liver parenchyma from the hepatic capsule. In normal adult liver, their most characteristic feature is the presence of cytoplasmic perinuclear droplets that are laden with retinyl (vitamin A) esters. Normal stellate cells display several patterns of intermediate filaments expression (e.g., desmin, vimentin, and/or glial fibrillary acidic protein) suggesting that there are subpopulations within this parental cell type. In the normal liver, stellate cells participate in retinoid storage, vasoregulation through endothelial cell interactions, extracellular matrix homeostasis, drug detoxification, immunotolerance, and possibly the preservation of hepatocyte mass through secretion of mitogens including hepatocyte growth factor. During liver injury, stellate cells activate into alpha smooth muscle actin-expressing contractile myofibroblasts, which contribute to vascular distortion and increased vascular resistance, thereby promoting portal hypertension. Other features of stellate cell activation include mitogen-mediated proliferation, increased fibrogenesis driven by connective tissue growth factor, and transforming growth factor beta 1, amplified inflammation and immunoregulation, and altered matrix degradation. Evolving areas of interest in stellate cell biology seek to understand mechanisms of their clearance during fibrosis resolution by either apoptosis, senescence, or reversion, and their contribution to hepatic stem cell amplification, regeneration, and hepatocellular cancer.

Hepatoprotective effects of Limonium tetragonum, edible medicinal halophyte growing near seashores

Background:

During the process of hepatic fibrosis, the activation of hepatic stellate cells (HSCs) is responsible for the increased formation and reduced degradation of extracellular matrix in the liver. By employing the hepatic stellate cell line, HSC-T6, it was found that the methanol extract of Limonium tetragonum, a halophyte living in salt marsh near south and western seashores of Korea significantly inhibited the proliferation of HSC-T6 cells.

Objective:

In the present study, we attempted to investigate the antifibrotic effects of the mathanolic extract of L. tetragonum (MELT) in the activated HSC-T6 cells.

Materials and Methods:

The proliferation of HSC-T6 was stimulated by culturing environment or platelet-derived growth factor (PDGF-BB) insult, and then the inhibitory activities of MELT were measured.

Results:

It was found that MELT suppressed the proliferation of the activated HSC-T6 in concentration- and time-dependent manners. The increased collagen deposition in the activated HSC-T6 cells was also decreased by the treatment of MELT. The maximal dose of MELT, however, had little effect on primary cultured rat hepatocytes. Wlammatory cytokine, tumor necrosis factor alpha (TNF-α) produced by lipopolysaccharide-stimulated RAW264.7 macrophages was inhibited by MELT.

Conclusion:

Collectively, the above results demonstrated that MELT suppressed HSCs proliferation but not in hepatocytes, implying that L. tetragonum may be useful candidates for developing therapeutic agents for the prevention and treatment of hepatic fibrosis.