Hepatic Fibrosis Tissues Research Articles

MiR-30c and miR-193 are a part of the TGF-β-dependent regulatory network controlling extracellular matrix genes in liver fibrosis.

MicroRNAs (miRNAs) have recently emerged as novel regulators in liver fibrosis. miR-30c and miR-193 are involved in fibrotic remodeling processes and cancer development, respectively. This study aimed to explore the role of miR-30c and miR-193 in liver fibrosis. The regulation of miRNAs in carbon tetrachloride-induced liver fibrosis was analyzed by microarray. Expression patterns of miR-193 and miR-30c were further confirmed in fibrotic liver samples obtained from two murine models of hepatic fibrosis and human tissues. On a functional level, miRNA levels were analyzed in the context of transforming growth factor (TGF-β) mediated activation of hepatic stellate cells (HSCs). Finally, predicted targets were assessed for their roles in fibrosis by transfecting murine HSCs with miRNA mimics. Microarray analysis in murine fibrotic livers revealed a panel of 44 dysregulated miRNAs. In addition to previously established miRNAs known to be regulated in liver fibrosis in a TGF-β-dependent manner (e.g., miR-29, miR-133), miR-193 and miR-30c were observed to be specifically downregulated not only in experimental hepatofibrogenesis but also in human liver fibrosis, while they showed a reciprocal expression pattern after recovery from liver fibrosis. Functional experiments confirmed the TGF-β-dependent downregulation of these respective new miRNAs in HSCs. Finally, we identified TGF-β2 and SNAIL1, important regulators of extracellular matrix, as potential target genes of miR-193 and miR-30 in liver fibrosis. These results suggest that miR-30 and miR-193 are members of a network of miRNAs modifying the TGF-β-dependent regulation of extracellular matrix-related genes in HSCs in the manifestation and resolution of liver fibrosis.

Periostin down-regulation attenuates the pro-fibrogenic response of hepatic stellate cells induced by TGF-β1.

Liver fibrosis is characterized by an exacerbated accumulation of deposition of the extracellular matrix (ECM), and the activation of hepatic stellate cells (HSC) plays a pivotal role in the development of liver fibrosis. Periostin has been shown to regulate cell adhesion, proliferation, migration and apoptosis; however, the involvement of periostin and its role in transforming growth factor (TGF)-β1-induced HSC activation remains unclear. We used RT-PCR and Western blot to evaluate the expression level of periostin in hepatic fibrosis tissues and HSCs, respectively. Cell proliferation was determined using the Cell Proliferation ELISA BrdU kit, cell cycle was analysed by flow cytometry. The expression of α-smooth muscle actin (α-SMA), collagen I, TGF-β1, p-Smad2 and p-Smad3 were determined by western blot. Our study found that periostin was up-regulated in liver fibrotic tissues and activated HSCs. In addition, siRNA-periostin suppressed TGF-β1-induced HSC proliferation. The HSC transfected with siRNA-periostin significantly inhibited TGF-β1-induced expression levels of α-SMA and collagen I. Furthermore, TGF-β1 stimulated the expression of periostin, and siRNA-periostin attenuated TGF-β1-induced Smad2/3 activation in HSCs. These results suggest that periostin may function as a novel regulator to modulate HSC activation, potentially by promoting the TGF-β1/Smad signalling pathway, and propose a strategy to target periostin for the treatment of liver fibrosis.

β-catenin is overexpressed in hepatic fibrosis and blockage of Wnt/β-catenin signaling inhibits hepatic stellate cell activation

β-catenin, a core component of Wnt/β-catenin signaling, has been shown to be an important regulator of cellular proliferation and differentiation. Abnormal activation of Wnt/β-catenin signaling promotes tissue fibrogenesis. In the present study, the role of β-catenin during liver fibrogenesis was analyzed and the functional effects of β-catenin gene silencing in hepatic stellate cells (HSCs) using small interfering (si)RNA were investigated. The expression of β-catenin in human hepatic fibrosis tissues of different grades and normal human hepatic tissues was examined using immunohistochemistry. To inhibit the Wnt/β-catenin signaling pathway, siRNA for β-catenin was developed and transiently transfected into HSC-T6 cells using Lipofectamine 2000. β-catenin expression was evaluated by quantitative polymerase chain reaction (qPCR) and western blot analysis. The expression of collagen types I and III was evaluated by qPCR and immunofluorescent staining. Cellular proliferation and the cell cycle were analyzed using a methyl thiazolyl tetrazolium assay. Apoptosis was assessed by Annexin V staining. A higher expression level of β-catenin was identified in the patients with high-grade hepatic fibrosis in comparison with that of the normal controls. Additionally, β-catenin siRNA molecules were successfully transfected into HSCs and induced inhibition of β-catenin expression in a time-dependent manner. β-catenin siRNA treatment also inhibited synthesis of collagen types I and I in transfected HSCs. Furthermore, compared with those of the control group, siRNA-mediated knockdown of β-catenin in HSC-T6 cells inhibited cell proliferation and resulted in cell apoptosis. This study suggests a significant functional role for β-catenin in the development of liver fibrosis and demonstrates that downregulation of the Wnt/β-catenin signaling pathway inhibits HSC activation. Thus, this study provides a novel strategy for the treatment of hepatic fibrosis.

Recent advances in dietary supplementation, in treating non-alcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is currently known as the most common liver problem, characterized by excessive lipid accumulation in hepatocytes, which may progress to other liver diseases such as nonalcoholic steatohepatitis, hepatic tissue fibrosis, liver cirrhosis, and failure or hepatocellular carcinoma. Since NAFLD is positively associated with the development of obesity, insulin resistance, and ultimately type 2 diabetes mellitus, it is often regarded as the hepatic manifestation of the metabolic syndrome. No pharmacologic treatment has yet been proven for this disease. For most patients with presumed or confirmed NAFLD, the only proven strategy is to offer lifestyle advice that can lead to sustained weight loss. Since insulin resistance, oxidative stress, inflammation, and necro-apoptosis are involved in NAFLD pathogenesis, it seems that every potential therapeutic agent should target one or some of these pathologic events. There are many well known anti-oxidants, anti-inflammatory, and insulin sensitizer dietary supplements which have shown beneficial effects on NAFLD improvement in animal and human studies. The purpose of this review is to explore the existing evidences on dietary supplements considered to have hepatoprotective properties, and to present some proposed mechanisms by which they may protect against NAFLD.

Dielectric properties of human liver from 10 Hz to 100 MHz: normal liver, hepatocellular carcinoma, hepatic fibrosis and liver hemangioma.

The dielectric properties of human liver were determined by characterization of tissue absorption and coupling of electromagnetic energy in the electromagnetic field. In this study the ex-vivo dielectric properties of human hepatocellular carcinoma (well and moderately differentiated), liver hemangioma, hepatic fibrosis (stages S1 and S2), and normal liver tissue were measured and analyzed over the frequency range of 10 Hz to 100 MHz. The dielectric properties over the frequency range can reflect tissue information including biological macromolecules, vesicles, and cellular membrane; these information aids in distinguishing different physiological states and lesions. The ex-vivo conductivity, permittivity, resistivity, as well as the characteristic parameters between the lesions and normal liver were analyzed and their differences were also verified. The data can contribute to developing bioelectric applications for tissue diagnostics and creating more accurate computer models for medical applications.

Monoclonal Antibody Preparation and Expression Profile Analysis of a Novel Hepatoma Associated Gene

Hepatoma associated gene (HTA), a gene screened and cloned by our previous research, was specifically expressed in certain kinds of tumors and had a cancer-promoting role in hepatocellular carcinoma (HCC). To further elucidate the mechanism of HTA in hepatoma carcinogenesis and its potential role as a cancer biomarker, refolded HTA protein (HTA) was obtained by prokaryotic recombinant expression system and immobilized metal affinity chromatography. Then anti-HTA monoclonal antibody (mAb) was produced by hybridoma technique. Using the high titer anti-HTA mAb with high specificity obtained, the expression profile of HTA was analysed by immunohistochemistry staining. It showed that HTA expressed specifically in some kinds of tumors, and didn't express in almost any of the normal tissues. The positive expression rate and expression quantity of HTA was significantly higher in HCC tissues than in hepatic cirrhosis tissues, hepatic fibrosis tissues and normal hepatic tissues. The expression of HTA was positively correlated with hepatoma carcinogenic process.

Inhibition effect of small interfering RNA targeting connective tissue growth factor on liver fibrosis in rats

To design and synthesize small interfering RNA (siRNA) targeting connective tissue growth factor (CTGF) and to investigate its effect on liver fibrosis. The interference sequence of CTGF was designed and synthesized. Rat hepatic fibrosis model was induced by intraperitoneal injection of 40 % CCl4(3 ml/kg). Thirty male rats were randomly divided into 5 groups: in normal control and model groups rats received tail vein injection of normal saline every 3 days for 8 consecutive weeks; in preventive group rats received tail vein injection of CTGF siRNA (0.1 mg/kg) every 3 days for 8 weeks; in 2-w treatment group CTGF siRNA was given for 6 weeks starting from two weeks after CCl4 injection; in 4-w treatment group CTGF siRNA was given for 4 weeks starting 4 weeks after CCl4 injection. The serum and hepatic tissue samples were harvested 3 days after the last CCl4 injection. Hepatic fibrosis indices were measured. Expression of CTGF mRNA and protein in the liver was evaluated by RT-PCR and Western blot, respectively. Fibrosis in rat liver was analyzed by Masson staining. Compared with model group (0.544 0.019), the expression of CTGF mRNA and protein in liver of both preventive(0.105 ± 0.003) and 2-w treatment groups (0.190 ± 0.006) were markedly down-regulated (P<0.05). Inflammation, necrosis and fibrosis in hepatic tissue were significantly attenuated. In addition, the serum ration of liver fibrosis indices was greatly reduced(P<0.05). Compared with preventive and 2-w treatment groups, the expression of CTGF mRNA and protein in liver in 4 weeks of treatment group were up-regulated (P<0.05); inflammation, necrosis and fibrosis in hepatic tissue were relative increased; and the serum concentrations of liver fibrosis indices were relatively higher (P<0.05). The highly effective CTGF siRNA has been successfully synthesized, which can inhibit CTGF expression in liver, prevent hepatic fibrosis and its progress in rats.

Expression and significance of CXCL5 and CXCL8 in hepatic fibrosis and cirrhosis tissues

Objective To investigate the level of chemotactic factors(CXCL5 and CXCL8)in hepatic fibrosis and cirrhosis tissue.Methods Hepatic tissues were obtained from 9 patients with hepatic hemangioma (hepatic hemangioma group),10 patients with liver fibrosis(liver fibrosis group)and 11 patients with liver cirrhosis(1iver cirrhosis group)at Nanfang Hospital from May 2008 to May 2009.The contents of CXCL5 and CXCL8 in hepatic tissue were assayed by ELISA.All data were analyzed by one-way ANOVA,Pearson rank correlation or Spearman correlation.Results The contents of CXCL5 and CXCL8 were(0.8±0.7)ng/g and(6.2±3.7)ng/g in hepatic hemangioma group,(2.0±2.0)ng/g and(11.6±3.5)ng/g in liver fibrosis group and (17.1±4.8)ng/g and(12.3±3.9)ng/g in liver cirrhosis group,with significant difference among the 3 groups (F=60.050,7.690,P＜0.05).The expression of CXCL5 was correlated with the content of alanine aminotransferase(ALT),aspartate aminotransferase(AST)and prothrombin time(PT)(r=0.502,0.468,0.523,P＜0.05):the expression of CXCL8 was correlated with the content of ALT,AST.total bilirubin and PT(r=0.477,0.504,0.537,0.431,P＜0.05).Conclusions With the aggravation of hepatic fibrosis,the contents of CXCL5 and CXCL8 are increased with different patterns.The changes of CXCL5 and CXCL8 are related with the injury of liver,but the changes of CXCL5 and CXCL8 do not correspond with the degree of the injury of liver. Key words: Liver cirrhosis; CXCL5; CXCL8; Chemotactic factor

The effect of urokinase on hepatic fibrogenesis in rats

To investigate the effect of urokinase on hepatic fibrogenesis in rats. Hepatic fibrosis was induced in rats by complex pathogenic factors including subcutaneous injections of carbon tetrachloride, alcohol and cholesterol feeding. Animals were randomly divided into 3 groups: normal control group, hepatic fibrosis group (complex pathogenic factors for 6 weeks), UK prevention group (complex pathogenic factors+UK for 6 weeks). The animals were sacrificed at the end of week 6. The expression of alpha-SMA, uPA, PAI-1, TGFb1, TIMP-1, collagen type I and type III proteins in hepatic fibrosis tissue was detected by immunohistochemistry, the expression of PAI-1 and TGFb1 mRNA in the hepatic fibrosis tissue was quantified by real time RT-PCR. The serum levels of hyaluronicacid (HA), alanine aminotransferase (ALT), aspartate aminotransferase (AST), bilirubin (TBil) and the content of liver hydroxyproline (Hyp) were detected using ELISA kits. The serum ALT, AST, TBil, HA and the content of liver Hyp were (46.66+/-6.30) U/L, (126.26+/-31.65) U/L, (31.11+/-4.20) micromol/L, (109.70+/-18.81) microg/L and (0.98+/-0.09) mg/(g liver), respectively, in UK prevention group, which were significantly lower than those [(101.57+/-11.97) U/L, (205.89+/-56.26) U/L, (67.75+/-2.75) micromol/L, (184.43+/-32.36) microg/L and (1.65+/-0.16) mg/(g liver), respectively] in hepatic fibrosis group (q = 3.3801-20.0061, P < 0.01). The levels of a-SMA, collagen type I, type III, TIMP-1, PAI-1, TGFb1 proteins were (299.27+/-37.36), (210.05+/-27.17), (192.94+/-24.48), (213.70+/-32.21), (204.25+/-17.92), (205.97+/-23.81), respectively, in UK prevention group, which were significantly lower than those [(418.83+/-30.21), (323.77+/-21.53), (302.37+/-31.43), (376.63+/-25.19), (313.53+/-26.67) and (327.42+/-36.75), respectively] in hepatic fibrosis group. The level of uPA protein was increased, and the expression of PAI-1, TGFb1 mRNA in hepatic fibrosis tissue was decreased in UK prevention group. In the early stage of hepatic fibrogenesis, urokinase can attenuate the progression of rat hepatic fibrosis via upregulation of uPA, downregulation of TGFb1, and inhibition of HSC activation.

102 Inhibition of Reactive Oxygen Species Impairs Healing in a Model of Tissue Ischemia

Reactive oxygen species (ROS) play a major role in recruiting and activating inflammatory cells, inducing angiogenesis, fibroblast proliferation, and collagen synthesis, all processes essential to wound healing. However, the same mediators have been implicated in pulmonary and hepatic fibrosis, vascular occlusion, and necrotic tissue damage. We have previously shown that hyperbaric oxygen caused a prolonged elevation of VEGF and delayed wound healing in a rat model of tissue ischemia. In this study we examine the effect of the ROS scavenger, n-acetylcysteine (NAC), on ischemic wound healing. NAC is a virtually nontoxic free radical scavenger that has been used in many experimental studies to block ROS-mediated signaling. Methods: Male Sprague-Dawley rats underwent creation of the ischemic flap previously validated by this laboratory. This model provides two ischemic and two nonischemic excisional wounds. Rats were treated daily with HBO for 90 minutes at 2.4 atm, HBO plus 150 mg/kg NAC intraperitoneal, or control (neither HBO nor NAC). Wounds were analyzed for surface area, lactate, and VEGF. Results: The HBO/NAC-treated animals had markedly impaired healing of their ischemic wounds at day 7 (0.105 ± .005 cm vs. 0.068 ± .002 cm for ctl and 0.064 ± .006 for HBO) and a twofold elevation of VEGF (120 pg/mg protein vs. 60 pg/mg protein). Lactate levels were not altered by NAC treatment and non-ischemic wounds showed no difference in healing, lactate, or VEGF. Conclusion: Reactive oxygen species are required for wound healing. Our initial hypothesis was that the delay in wound closure with HBO treatment was due to excess ROS and that NAC would improve healing. The finding of elevated VEGF and delayed wound healing in the presence of a potent free radical scavenger suggests that blocking ROS signaling prevents the normal mitogenic response to VEGF. Additional studies to examine the VEGF receptor and tyrosine kinase activation will further elucidate the mechanism of ROS signaling in response to HBO treatment.

Differential analysis of associated proteome in hepatic fibrosis tissue

To develop the 2-DE profiles of proteome from hepatic fibrosis tissue and preliminarily analyze the differential expression of proteome. The differential expression of proteins were analyzed by imaging analysis and MALDI-TOF-MS after the total protein was extracted from the hepatic fibrosis tissue and the normal liver tissue by 2-DE. 3 proteins were verified by in Western-blotting. Fifty-nine differentially expressed protein were found in the proteome profile analysis of these two types of tissue, among which 30 protein spots were up-regulated and 29 protein spots were down-regulated in these hepatic fibrosis tissues. Fifteen protein spots with the differential expressions more than 3 times were analyzed by peptide mass fingerprint (PMF) and 10 differentially expressed proteins were found to be related with cell signal transduction, cell proliferation, and oxidative stress. Western-blotting results of 14-3-3beta, DJ-1, and PEBP were consistent with those by the 2-DE examination. Some differentially expressed proteins have been found in the hepatic fibrosis tissue and the normal liver tissue. These data provided a fundamental basis for further study of the mechanism of hepatic fibrogenesis. Proteome;

Correlation of pathology in chronic hepatitis B to viral markers in serum and hepatic tissue

To investigate the relation of the viral markers in serum and those expressed by hepatocytes to pathological lesions of hepatic tissue in patients with chronic hepatitis B. The relation of viral markers including HBsAg, HBsAb, HBeAg, HBeAb, HBcAb and HBV DNA in serum of 647 patients with chronic hepatitis B and HBsAg, HBcAg expressed by hepatocytes in 418 of these patients to pathological lesions of hepatic tissue was determined. Viral markers in serum and those expressed by hepatocytes in patients with chronic hepatitis B were closely correlated with pathological lesions of hepatic tissue. The degree of inflammation and fibrosis in hepatic tissue is milder in serum HBsAg, HBeAb, HBcAb positive and HBV DNA negative patients but more serious in those with negative hepatocytic expression of HBsAg and HBcAg. HBV DNA is not significantly associated with pathological lesions of hepatic tissue.

Morphological and serum hyaluronic acid, laminin and type IV collagen changes in dimethylnitrosamine-induced hepatic fibrosis of rats

To study the morphological and serum hyaluronic acid (HA), laminin (LN), and type IV collagen changes in hepatic fibrosis of rats induced by dimethylnitrosamine (DMN). The rat model of liver fibrosis was induced by DMN. Serum HA, type IV collagen, and LN were measured by ELISA. The liver/weight index and morphological changes were examined under electron microscope on d 7, 14, 21, and 28 by immunohistochemical alpha smooth muscle actin alpha-SMA staining as well as Sirius-red and HE staining. The levels of serum HA, type IV collagen and LN significantly increased from d 7 to d 28 (P = 0.043). The liver/weight index increased on d 7 and decreased on d 28. In the model group, the rat liver stained with HE and Sirius-red showed evident hemorrhage and necrosis in the central vein of hepatic 10 lobules on d 7. Thin fibrotic septa were formed joining central areas of the liver on d 14. The number of alpha-SMA positive cells was markedly increased in the model group. Transitional hepatic stellate cells were observed under electron microscope. All rats in the model group showed micronodular fibrosis in the hepatic parenchyma and a network of alpha-SMA positive cells. Typical myofibroblasts were embedded in the core of a fibrous septum. Compared to the control group, the area-density percentage of collagen fibrosis and pathologic grading were significantly different in the model group (P<0.05) on different d (7, 14, and 28). The area-density percentage of collagen fibrosis in hepatic tissue had a positive correlation with the levels of serum HA, LN, and type IV collagen. The morphological and serum HA, type IV collagen, and LN are changed in DMN-induced liver fibrosis in rats.

EXPRESSION OF TGF β1 RECEPTORS I &amp; II IN CONGENITAL HEPATIC FIBROSIS

5 Introduction. Congenital hepatic fibrosis is a rare disease characterized by portal fibrosis and biliary ductular ectasia. We previously demonstrated increased expression of TGF β1 and Thrombospondin 1 in congenital hepatic fibrosis tissue as well as in stellate cell conditioned media. TGF β1 exerts in biological effects through types I and II serine threonine kinase receptors, we sought to determine if this signaling pathway was altered in congenital hepatic fibrosis. Methods. Liver tissue homogenates and formalin-fixed tissue samples from patients with congenital hepatic fibrosis and normal controls were analyzed using anti-TGF β1 type I and II receptor antibodies. Semi quantitative evaluation of receptor expression using optical densitometry of Western blot isolates of both receptors was used for tissue homogenates. Immunohistochemical studies localized the extent and site of receptor expression on hepatocytes and cholangiocytes. Results. Congenital hepatic fibrosis liver tissue stained strongly for both types I and II receptors. The distribution of staining showed marked increase in hepatocyte expression for both types I and II. Cholangiocytes lacked expression of type II receptor but stained strongly for type I. Whole liver expression of type I and II receptor as analyzed by Western blot and optical densitometry showed increased expression of both type I and II receptors. The ratio of type I/II receptor expression was markedly different from normal liver. Conclusions. In congenital hepatic fibrosis, expression of TGF β1 receptors is increased. This reflects the increased expression of the cytokine itself. The distribution of types I and II receptor expression is markedly different between hepatocytes and biliary epithelial cells. The absence of type II receptor expression in the ectatic biliary epithelium of the fibrotic livers suggests that the epithelial hyperplasia may be related to the loss of the growth inhibitory response of TGF β1. This phenomenon of resistance to the inhibitory effect of TGF β1 is known in several cancer cell lines. Further in vitro studies on isolated cholangiocytes and hepatocytes are under way to further define these findings.

Increased expression of transforming growth factor-beta1 and thrombospondin-1 in congenital hepatic fibrosis: possible role of the hepatic stellate cell.

Congenital hepatic fibrosis is a rare disease characterized by portal tract fibrosis and biliary duct ectasia. It is associated with autosomal recessive polycystic kidney disease and rarely progresses to cirrhosis. The activated stellate cell has been implicated in the pathogenesis of alcohol- or inflammation-mediated cirrhosis through fibrogenic proteins such as transforming growth factor-beta1; however, the role of the stellate cell in pure, noninflammatory fibrosis is unknown. It has been hypothesized that fibrosis in congenital hepatic fibrosis may be caused by upregulation of transforming growth factor-beta1 and thrombospondin-1, and that the hepatic stellate cell may be the mediator of these proteins. Human liver tissue samples from patients with congenital hepatic fibrosis (n = 9) and from normal patients (n = 3) were analyzed. Tissue homogenates from both groups were analyzed for transforming growth factor-beta1 protein and mRNA by Western blot analysis and in situ hybridization, respectively. Immunolocalization studies were performed in fixed tissue sections from both groups. Stellate cells were cultured from livers exhibiting congenital hepatic fibrosis and confirmed by desmin staining. The cells were cultured in serum-free medium for 48 hours, and media were collected and analyzed by Western blot analysis for thrombospondin-1 and transforming growth factor-beta1. Congenital hepatic fibrosis liver tissue homogenates had higher levels of thrombospondin-1 and transforming growth factor-beta1 protein than in normal livers. In congenital hepatic fibrosis tissue, transforming growth factor-beta1 was more highly expressed in the ectatic biliary epithelium and the perisinusoidal space, whereas thrombospondin-1 localized most intensely to the hepatocytes and spared the bile ducts. Congenital hepatic fibrosis-derived stellate cells secreted both thrombospondin-1 and transforming growth factor-beta1, in vitro. Transforming growth factor-beta1 and thrombospondin-1 may play a role in the pathogenesis of liver fibrosis in patients with congenital hepatic fibrosis. One potential source of these fibrogenic proteins is the hepatic stellate cell.