Experimental model of hepatic fibrosis following repeated periportal necrosis induced by allylalcohol

Novel human hepatic organoid model enables testing of drug-induced liver fibrosis in vitro

Current models for in vitro fibrosis consist of simple mono-layer cultures of rodent hepatic stellate cells (HSC), ignoring the role of hepatocyte injury. We aimed to develop a method allowing the detection of hepatocyte-mediated and drug-induced liver fibrosis. We used HepaRG (Hep) and primary human HSCs cultured as 3D spheroids in 96-well plates. These resulting scaffold-free organoids were characterized for CYP induction, albumin secretion, and hepatocyte and HSC-specific gene expression by qPCR. The metabolic competence of the organoid over 21 days allows activation of HSCs in the organoid in a drug- and hepatocyte-dependent manner. After a single dose or repeated exposure for 14 days to the pro-fibrotic compounds Allyl alcohol and Methotrexate, hepatic organoids display fibrotic features such as HSC activation, collagen secretion and deposition. Acetaminophen was identified by these organoids as an inducer of hepatotoxic-mediated HSC activation which was confirmed in vivo in mice. This novel hepatic organoid culture model is the first that can detect hepatocyte-dependent and compound-induced HSC activation, thereby representing an important step forward towards in vitro compound testing for drug-induced liver fibrosis.

Immunomodulatory effects of transforming growth factor-β in the liver

Members of the transforming growth factor-β (TGF-β) family are potent regulatory cytokines that affect multiple cell types of the immune system mediating pro-inflammatory or anti-inflammatory responses. In the liver, TGF-β is produced by a multitude of non-parenchymal liver cells including hepatic stellate cells (HSCs), liver sinusoidal endothelial cells (LSECs), Kupffer cells (KCs), and dendritic cells (DCs) as well as natural killer (NK) T cells among other hepatic lymphocytes. The effect of TGF-β on other cells is highly versatile. In concert with other soluble factors, it controls the maturation, differentiation and activity of various T cell subsets that either prevent or actuate infections, graft-versus-host reactions, immune diseases, and cancer formation. During the last decades, it became evident that some TGFB1 polymorphisms are associated with the pathogenesis of hepatic disease and that plasma TGF-β is a suitable biomarker to detect liver lesions. Moreover, since TGF-β has capacity to influence the quantity and quality of T cell subsets as well as their activity, it is obvious that a well-balanced TGF-β activity is essential for liver homeostasis. In the present review, we highlight some pivotal functions of TGF-β in hepatic immunobiology. We discuss its regulatory function on adaptive immunity, the impact on differentiation of various T cell subsets, its crosstalk with Toll like receptor signaling, and its contribution to functional impairment of the liver.

Human adipose tissue derived stem cells promote liver regeneration in a rat model of toxic injury

In the light of the persisting lack of donor organs and the risks of allotransplantations, the possibility of liver regeneration with autologous stem cells from adipose tissue (ADSC) is an intriguing alternative. Using a model of a toxic liver damage in Sprague Dawley rats, generated by repetitive intraperitoneal application of retrorsine and allyl alcohol, the ability of human ADSC to support the restoration of liver function was investigated. A two-thirds hepatectomy was performed, and human ADSC were injected into one remaining liver lobe in group 1 (n = 20). Injection of cell culture medium performed in group 2 (n = 20) served as control. Cyclosporine was applied to achieve immunotolerance. Blood samples were drawn weekly after surgery to determine liver-correlated blood values. Six and twelve weeks after surgery, animals were sacrificed and histological sections were analyzed. ADSC significantly raised postoperative albumin (P < 0.017), total protein (P < 0.031), glutamic oxaloacetic transaminase (P < 0.001), and lactate dehydrogenase (P < 0.04) levels compared to injection of cell culture medium alone. Transplanted cells could be found up to twelve weeks after surgery in histological sections. This study points towards ADSC being a promising alternative to hepatocyte or liver organ transplantation in patients with severe liver failure.

The ToxBank Data Warehouse: Supporting the Replacement of In Vivo Repeated Dose Systemic Toxicity Testing

The aim of the SEURAT-1 (Safety Evaluation Ultimately Replacing Animal Testing-1) research cluster, comprised of seven EU FP7 Health projects co-financed by Cosmetics Europe, is to generate a proof-of-concept to show how the latest technologies, systems toxicology and toxicogenomics can be combined to deliver a test replacement for repeated dose systemic toxicity testing on animals. The SEURAT-1 strategy is to adopt a mode-of-action framework to describe repeated dose toxicity, combining in vitro and in silico methods to derive predictions of in vivo toxicity responses. ToxBank is the cross-cluster infrastructure project whose activities include the development of a data warehouse to provide a web-accessible shared repository of research data and protocols, a physical compounds repository, reference or "gold compounds" for use across the cluster (available via wiki.toxbank.net), and a reference resource for biomaterials. Core technologies used in the data warehouse include the ISA-Tab universal data exchange format, REpresentational State Transfer (REST) web services, the W3C Resource Description Framework (RDF) and the OpenTox standards. We describe the design of the data warehouse based on cluster requirements, the implementation based on open standards, and finally the underlying concepts and initial results of a data analysis utilizing public data related to the gold compounds.

Taurine and liver diseases: a focus on the heterogeneous protective properties of taurine

Taurine (2-aminoethylsulfonic acid) has many physiological and pharmacological functions in most tissues. It is abundantly maintained in the liver by both endogenous biosynthesis and exogenous transport, but is decreased in liver diseases. In the hepatic lobule, there are heterogeneous differences in metabolism between the pericentral (PC) and periportal regions, and the distributions of the biosynthesis capacity and specific taurine transporter expression are predominantly in the PC region. In cases of depletion of hepatic taurine level, serious liver damages were observed in the PC region. Taurine has protective effects against xenobiotics-induced liver damages in the PC region, but not xenobiotics-induced PP region damages. The xenobiotics that injure the PC region are mainly catabolized by NADPH-dependent cytochrome P450 2E1 that is also predominantly expressed in the PC region. Taurine treatment seems to be a useful agent for CYP2E1-related liver diseases with predominant damages in the PC region.

Antifibrogenic effects of tamoxifen in a rat model of periportal hepatic fibrosis

BACKGROUNDS/AIMS

It has been reported that tamoxifen may affect hepatoma cell growth in vitro by suppressing transforming growth factor beta-1 (TGF-beta1) expression, suggesting that tamoxifen might also retard fibrogenesis. Thus, we examined whether tamoxifen might suppress TGF-beta1 expression and consequently inhibit the process of hepatic fibrosis in vivo.

METHODS

To induce periportal hepatic fibrosis, 50 male adult Sprague-Dawley rats were injected with 0.62 mmol/kg of allyl alcohol, intraperitoneally, twice a week for 8 weeks. Hepatic fibrosis scores, intrahepatic collagen levels and plasma TGF-beta1 expression levels were evaluated in three groups of 10 rats orally administered tamoxifen at 1, 5 and 10 mg/kg, respectively, and in 20 controls. Messenger RNAs (mRNAs) encoding TGF-beta1 and TGF-beta receptors in liver tissue were semiquantified using reverse transcriptase polymerase chain reaction.

RESULTS

Hepatic fibrosis scores decreased progressively as the dose of tamoxifen increased, resulting in a significant change in rats treated with tamoxifen at 10 mg/kg compared with controls (P=0.018). Intrahepatic collagen content was significantly less in the group treated with tamoxifen at 10 mg/kg compared with the control (P=0.045). Plasma TGF-beta1 levels were also significantly lower in rats treated with tamoxifen at 10 mg/kg compared with controls (P=0.007). All three concentrations of tamoxifen tested decreased the expression levels of hepatic TGF-beta1 mRNA and type I TGF-beta receptor (TGF-beta RI) mRNA to similar extents.

CONCLUSIONS

Tamoxifen seems to inhibit the process of hepatic fibrosis dose-dependently by suppressing the transcription of TGF-beta1 and TGF-beta RI in an experimental model of periportal hepatic fibrosis.

Endothelial nitric oxide synthase is a critical factor in experimental liver fibrosis

Reduced expression of endothelial nitric oxide synthase (eNOS) in chronic liver disease can reduce hepatic perfusion and accelerate fibrosis. The relationship between eNOS expression and liver fibrogenesis remains unclear. We investigated whether L-arginine attenuated chronic liver fibrosis through eNOS expression. Chronic liver injury was induced by administration of carbon tetrachloride (CCl(4)) to mice for 8 weeks. 5-Methylisothiourea hemisulphate (SMT), an iNOS inhibitor, or L-arginine, a NOS substrate were injected subcutaneously. CCl(4)-induced hepatotoxicity, oxidative stress and accumulation of collagen were detected in the liver. The expression levels of inducible NOS (iNOS) and nuclear factor kappa-B (NF-kappaB) activity in the liver after CCl(4) treatment were increased but eNOS expression and activator protein-1 (AP-1) activity were decreased. Both SMT and L-arginine effectively reduced CCl(4) induced oxidative stress and collagen formation, but L-arginine showed a significantly greater suppression of collagen formation, iNOS expression and NF-kappaB activity. L-arginine also restored the level of eNOS and AP-1 activity. L-arginine was more effective than SMT in suppressing liver fibrosis. L-arginine might improve NO production which facilitates hepatic blood flow and thus retards liver fibrogenesis. Our results showed that the reduced eNOS expression in CCl(4)-treated mice was reversed by L-arginine. Furthermore, L-arginine also reversed the reduced AP-1 activity, an eNOS promoter.

Comprehensive characterization of serum clinical chemistry parameters and the identification of urinary superoxide dismutase in a carbon tetrachloride-induced model of hepatic fibrosis in the female Hanover Wistar rat

Carbon tetrachloride (CCl(4)) was used to induce liver fibrosis in the rat. Using this model, we have identified changes in serum and urinary clinical chemistry parameters, and characterized histopathological lesions in the liver. Two experiments were conducted. In Experiment 1, rats were dosed at six levels of CCl(4) (0.06-0.36 ml/kg) twice weekly for 6 weeks, followed by a 6-week non-dosing recovery period (week 12). Livers were removed for histology at 6 and 12 weeks and serum parameters analysed. In Experiment 2, rats were given seven dose levels of CCl(4) (0.4-1.0 ml/kg) twice weekly for 6 weeks, followed by a 6-week recovery period (week 12); urine samples were analysed at 3, 6, 9 and 12 weeks using one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Liver fibrosis was evident at 6 weeks in Experiments 1 and 2, and the activity of serum enzymes (including alanine aminotransferase, aspartate aminotransferase and glutamate dehydrogenase) was increased. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis (Experiment 2) revealed a protein band at 18.4 kDa in urine from rats treated with CCl(4), not present in control urine, which was identified as copper/zinc superoxide dismutase (Cu/Zn SOD). Western blotting revealed that SOD was increased in urine from rats treated with CCl(4) at 3 and 6 weeks, but not at 9 and 12 weeks. We conclude that Cu/Zn SOD is a urinary marker of hepatic necrosis, but not hepatic fibrosis.

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

AIM

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).

METHODS

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.

RESULTS

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.

CONCLUSION

The morphological and serum HA, type IV collagen, and LN are changed in DMN-induced liver fibrosis in rats.

Human mesenchymal stem cells xenografted directly to rat liver are differentiated into human hepatocytes without fusion

Hepatic transdifferentiation of bone marrow cells has been previously demonstrated by intravenous administration of donor cells, which may recirculate to the liver after undergoing proliferation and differentiation in the recipient's bone marrow. In the present study, to elucidate which cellular components of human bone marrow more potently differentiate into hepatocytes, we fractionated human bone marrow cells into mesenchymal stem cells (MSCs), CD34+ cells, and non-MSCs/CD34- cells and examined them by directly xenografting to allylalcohol (AA)-treated rat liver. Hepatocyte-like cells, as revealed by positive immunostaining for human-specific alpha-fetoprotein (AFP), albumin (Alb), cytokeratin 19 (CK19), cytokeratin 18 (CK18), and asialoglycoprotein receptor (AGPR), and by reverse transcription-polymerase chain reaction (RT-PCR) for expression of AFP and Alb mRNA, were observed only in recipient livers with MSC fractions. Cell fusion was not likely involved since both human and rat chromosomes were independently identified by fluorescence in situ hybridization (FISH). The differentiation appeared to follow the process of hepatic ontogeny, reprogramming of gene expression in the genome of MSCs, as evidenced by expression of the AFP gene at an early stage and the albumin gene at a later stage. In conclusion, we have demonstrated that MSCs are the most potent component in hepatic differentiation, as revealed by directly xenografting into rat livers.

Inhibitory effect of Huangqi Zhechong decoction on liver fibrosis in rat

AIM: To assess the inhibitory effect of Huangqi Zhechong decoction on hepatic fibrosis in rats induced by CCl₄ plus alcohol and high fat low protein diet.

METHODS: Male SD rats were randomly divided into hepatic fibrosis model group, control group and 3 treatment groups consisting of 12 rats in each group. Except for the normal control group, all the rats were subcutaneously injected with CCl₄ at a dosage of 3 mL/kg. In 3 treated groups, either high-dose group (9 mL/kg), or medium-dose group (6 mL/kg), or low-dose group (3 mL/kg) was daily gavaged with Huangqi Zhechong decoction, and saline vehicle was given to model and normal control rats. Enzyme-linked immunosorbent assay (ELISA) and biochemical examinations were used to determine the changes of alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronic acid (HA), laminin (LN), type-III-procollagen-N- peptide (PIIIP), and type IV collagen content in serum, and hydroxyproline (Hyp) content in liver after sacrificing the rats. Pathologic changes, particularly fibrosis were examined by hematoxylin and eosin (HE) and Van Gieson staining.

RESULTS: Compared with the model control group, serum ALT, AST, HA, LN, PIIIP and type IV collagen levels dropped markedly in Huangqi Zhechong decoction groups, especially in the medium-dose Huangqi Zhechong decoction group (1 954 ± 576 U/L vs 759 ± 380 U/L, 2 735 ± 786 U/L vs 1 259 ± 829 U/L, 42.74 ± 7.04 ng/mL vs 20.68 ± 5.85 ng/mL, 31.62 ± 5.84 ng/mL vs 14.87 ± 1.45 ng/mL, 3.26 ± 0.69 ng/mL vs 1.47 ± 0.46 ng/mL, 77.68 ± 20.23 ng/mL vs 25.64 ± 4.68 ng/mL, respectively) (P < 0.05). The Hyp content in liver tissue was also markedly decreased (26.47 ± 11.24 mg/mgprot vs 9.89 ± 3.74 mg/mgprot) (P < 0.01). Moreover, the stage of the rat liver fibrosis in Huangqi Zhechong decoction groups was lower than that in model group, and more dramatic drop was observed in medium-dose Huangqi Zhechong decoction group (P < 0.01).

CONCLUSION: Huangqi Zhechong decoction can inhibit hepatic fibrosis resulted from chronic liver injure, retard the development of cirrhosis, and notably ameliorate the liver function. It may be a safe and effective therapeutic drug for patients with fibrosis.

Suppression of expression extracellular matrix in hepatic fibrosis rat with tetrandrine and glycyrrhizinic acid

AIM

To investigate effects and mechanism of tetrandrine(Tet) and glycyrrhizinic acid(Glz) in combination on metabolism of extracellular matrix in hepatic fibrotic rats induced by carbon tetrachloride.

METHODS

The hepatic fibrosis model rats induced with carbon tetrachloride were grouped randomly into 5 mg/kg, 10 mg/kg, 20 mg/kg Tet, 5 mg/kgTet+50 mg/kgGlz, 10 mg/kgTet+50 mg/kgGlz, 20 mg/kgTet+50 mg/kgGlz and 50 mg/kgGlz groups. Rats in experimental groups were administrated with Tet and or Glz by gavage or peritoneal injection every day. Serum levels of HA, LN, and PIIIP were detected with radioimmunoassay. Histopathological change was examined with VG staining and observed under light-microscope. mRNA of collagen type I and III were evaluated by RT-PCR.

RESULTS

In comparison with model group, Tet and Glz in combination could markedly decrease serum levels of HA, LN and PIIIP(121.8±9.5 vs 58.4±7.6, 85.7±12.1 vs 46.2±7.3, 35.9±3.5 vs 23.5±2.9; P<0.05), and suppress the expressions of type I, III procollagen mRNA(0.53±0.07 vs 0.26±0.09, 0.47±0.05 vs 0.21±0.07; P<0.05), and reduce deposition of extracellular matrix. Compared with Tet (10mg/kg)only group, Tet with Glz in combination could markedly reduced the serum levels of HA, LN and PIIIP(69.2±11.1 vs 58.4±7.6; 52.3±6.7 vs 46.2±7.3; 29.9±3.2 vs 23.5±2.9; P<0.05), and inhibit the expression of type I, III procollagen mRNA(0.33±0.06 vs 0.26±0.09, 0.29±0.04 vs 0.21±0.07; P<0.05).

CONCLUSION

Tet and Glz in combination could inhibit expression and deposition of extracellular matrix in fibrotic rats more significantly than either Tet or Glz.