Newly proposed fibrosis staging criterion for assessing carbon tetrachloride- and albumin complex-induced liver fibrosis in rodents

The Role of Pyrazolo[3,4-d]pyrimidine-Based Kinase Inhibitors in The Attenuation of CCl4-Induced Liver Fibrosis in Rats

Liver Fibrosis can be life-threatening if left untreated as it may lead to serious, incurable complications. The common therapeutic approach is to reverse the fibrosis while the intervention is still applicable. Celecoxib was shown to exhibit some antifibrotic properties in the induced fibrotic liver in rats. The present study aimed to investigate the possible antifibrotic properties in CCl4-induced liver fibrosis in male Sprague–Dawley rats compared to celecoxib of three novel methoxylated pyrazolo[3,4-d]pyrimidines. The three newly synthesized compounds were proved to be safe candidates. They showed a therapeutic effect against severe CCl4-induced fibrosis but at different degrees. The three compounds were able to partially reverse hepatic architectural distortion and reduce the fibrotic severity by showing antioxidant properties reducing MDA with increasing GSH and SOD levels, remodeling the extracellular matrix proteins and liver enzymes balance, and reducing the level of proinflammatory (TNF-α and IL-6) and profibrogenic (TGF-β) cytokines. The results revealed that the dimethoxy-analog exhibited the greatest activity in all the previously mentioned parameters compared to celecoxib and the other two analogs which could be attributed to the different methoxylation patterns of the derivatives. Collectively, the dimethoxy-derivative could be considered a safe promising antifibrotic candidate.

Automated whole slide image analysis for a translational quantification of liver fibrosis

Current literature highlights the need for precise histological quantitative assessment of fibrosis which cannot be achieved by conventional scoring systems, inherent to their discontinuous values and reader-dependent variability. Here we used an automated image analysis software to measure fibrosis deposition in two relevant preclinical models of liver fibrosis, and established correlation with other quantitative fibrosis descriptors. Longitudinal quantification of liver fibrosis was carried out during progression of post-necrotic (CCl₄-induced) and metabolic (HF-CDAA feeding) models of chronic liver disease in mice. Whole slide images of picrosirius red-stained liver sections were analyzed using a fully automated, unsupervised software. Fibrosis was characterized by a significant increase of collagen proportionate area (CPA) at weeks 3 (CCl₄) and 8 (HF-CDAA) with a progressive increase up to week 18 and 24, respectively. CPA was compared to collagen content assessed biochemically by hydroxyproline assay (HYP) and by standard histological staging systems. CPA showed a high correlation with HYP content for CCl₄ (r = 0.8268) and HF-CDAA (r = 0.6799) models. High correlations were also found with Ishak score or its modified version (r = 0.9705) for CCl₄ and HF-CDAA (r = 0.9062) as well as with NASH CRN for HF-CDAA (r = 0.7937). Such correlations support the use of automated digital analysis as a reliable tool to evaluate the dynamics of liver fibrosis and efficacy of antifibrotic drug candidates in preclinical models.

Aberrant regulation of autophagy disturbs fibrotic liver regeneration after partial hepatectomy

Reports indicate that autophagy is essential for maintaining hepatocyte proliferative capacity during liver regeneration. However, the role of autophagy in fibrotic liver regeneration is incompletely elucidated. We investigated the deregulation of autophagic activities in liver regeneration after partial hepatectomy using a CCl4-induced fibrosis mouse model. The baseline autophagic activity was significantly increased in the fibrotic liver. After 50% partial hepatectomy (PHx), liver regeneration was remarkably decreased, accompanied by increased hepatocyte size and binuclearity ratio. Moreover, the expression of autophagy-related proteins was functionally deregulated and resulted in a reduction in the number of autophagosome and autophagosome–lysosome fusions. We further showed upregulation of autophagy activities through verapamil administration, improved hepatocyte proliferation capacity, and restricted cellular hypertrophy and binuclearity ratio. In conclusion, we demonstrated that the impairment of liver regeneration is associated with aberrant autophagy in fibrotic liver and that enhancing autophagy with verapamil may partially restore the impaired liver regeneration following PHx.

Assessment of Fibrotic Liver Regeneration After Partial Hepatectomy With Intravoxel Incoherent Motion Diffusion-Weighted Imaging: An Experimental Study in a Rat Model With Carbon Tetrachloride Induced Liver Injury

Purpose

To determine whether intravoxel incoherent motion (IVIM) parameters correlate with liver regeneration and function recovery after partial hepatectomy (PH) in rats with carbon tetrachloride (CCl₄)-induced liver fibrosis.

Methods

Sixty-two adult Sprague-Dawley rats were divided into the control group and the fibrosis group with CCl₄ injection for 8 weeks. At the end of the 8th week, all rats received left lateral lobe liver resection. Within each group, IVIM imaging (n = 10/group) and histologic and biochemical analyses (n = 3/group/time point) were performed pre- and post-PH (on days 1, 2, 3, 5, 7, 14, and 21). Differences in liver IVIM parameters and correlation between IVIM parameters and Ki-67 indices, hepatocyte diameter, alanine transaminase (ALT), aspartate aminotransferase (AST), and total bilirubin (TBil) values were analyzed.

Results

Post-PH, liver true diffusion coefficient (D) values decreased and pseudodiffusion coefficient (D*) and perfusion fraction (PF) values increased, then recovered to pre-PH levels gradually in both fibrosis and control rats. PF in fibrosis group were significantly higher than in controls from 3 to 21 days (P < 0.05). In fibrosis rats, both Ki-67 indices and hepatocyte diameters increased, and a strong correlation was found between PF and Ki-67 indices (r = −0.756; P = 0.03), D* and PF values and ALT, AST, and TBil values (r = −0.762 to −0.905; P < 0.05). In control rats, only hepatocyte diameters increased, and all IVIM parameters correlated well with hepatocyte diameters, ALT, AST and TBil values (r = 0.810 to −1.000; P < 0.05).

Conclusion

The regeneration pattern in fibrotic liver tissue was different compared with control livers. IVIM parameters can monitor liver regeneration and functional recovery non-invasively after PH.

TGFβ2 and TGFβ3 isoforms drive fibrotic disease pathogenesis

Transforming growth factor-β (TGFβ) is a key driver of fibrogenesis. Three TGFβ isoforms (TGFβ1, TGFβ2, and TGFβ3) in mammals have distinct functions in embryonic development; however, the postnatal pathological roles and activation mechanisms of TGFβ2 and TGFβ3 have not been well characterized. Here, we show that the latent forms of TGFβ2 and TGFβ3 can be activated by integrin-independent mechanisms and have lower activation thresholds compared to TGFβ1. Unlike TGFB1, TGFB2 and TGFB3 expression is increased in human lung and liver fibrotic tissues compared to healthy control tissues. Thus, TGFβ2 and TGFβ3 may play a pathological role in fibrosis. Inducible conditional knockout mice and anti-TGFβ isoform-selective antibodies demonstrated that TGFβ2 and TGFβ3 are independently involved in mouse fibrosis models in vivo, and selective TGFβ2 and TGFβ3 inhibition does not lead to the increased inflammation observed with pan-TGFβ isoform inhibition. A cocrystal structure of a TGFβ2-anti-TGFβ2/3 antibody complex reveals an allosteric isoform-selective inhibitory mechanism. Therefore, inhibiting TGFβ2 and/or TGFβ3 while sparing TGFβ1 may alleviate fibrosis without toxicity concerns associated with pan-TGFβ blockade.

High-resolution three-dimensional visualization of hepatic sinusoids in cirrhotic rats via serial histological sections

AIM

As a specialized intraparenchymal vascular conduit, hepatic sinusoids play a key role in liver microcirculation. This study aimed to explore the three-dimensional (3D) morphological changes of cirrhotic sinusoids by serial histological sections.

METHODS

Cirrhosis was induced by tail vein injection of albumin in Wistar rats with a positive antibody. A total of 356 serial histological sections were prepared from liver tissue blocks of normal and cirrhotic rats. The optical microscope images were registered and reconstructed, and 3D reconstructions of the fine structures of fibrous tissues and sinusoids were subsequently visualized.

RESULTS

The fibrosis area of the cirrhotic sample was 6-16 times that of the normal sample (P<0.001). Cirrhosis led to obvious changes in the distribution and morphology of sinusoids, which were mainly manifested as dilation, increased quantity and disordered distribution. Compared with normal liver, cirrhotic liver has a significantly increased volume ratio, number and volume of sinusoids (1.63-, 0.53-, and 1.75-fold, respectively, P<0.001). Furthermore, the samples were further divided into three zones according to the oxygen supply, and there were significant differences in the morphology of the sinusoids in the normal and cirrhotic samples (P<0.05). In particular, morphological parameters of the cirrhotic sinusoids near the portal area were obviously greater than those in the normal liver (P<0.05).

CONCLUSION

3D morphological structures of hepatic sinusoids were reconstructed, and the adaptive microstructure changes of cirrhotic sinusoids were accurately measured, which has an important implications for the study of hepatic microcirculation and pathological changes of cirrhosis.

2-Methoxyestradiol attenuates liver fibrosis in mice: implications for M2 macrophages

Liver fibrosis is a major health problem worldwide due to its serious complications including cirrhosis and liver cancer. 2-Methoxyestradiol (2-ME) is an end metabolite of estradiol with anti-proliferative, antioxidant, and anti-inflammatory activities. However, the protective role of 2-ME in liver fibrosis has not been fully investigated. The aim of this study was to determine the protective effect of 2-ME in carbon tetrachloride (CCl₄)-induced liver fibrosis in mice. Animals were injected intraperitoneally with CCl₄ twice weekly for 6 weeks. 2-ME 50 mg/kg or 100 mg/kg was administrated intraperitoneally every day over the same period. Our data showed that 2-ME reduced the extent of liver toxicity and fibrosis due to CCl₄ exposure. It restored the elevated serum liver enzymes aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) levels and ameliorated oxidative status. In addition, 2-ME significantly reduced collagen deposition and alpha-smooth muscle actin (α-SMA) protein expressions. Furthermore, 2-ME markedly lowered macrophage infiltration and macrophage alternative activation marker chitinase-like molecules (CHI3L3/YM1). The results of this study indicate an important protective activity of 2-ME in liver fibrosis and highlight the role of macrophage recruitment and alternative activation as a possible target.

Diffusion-weighted imaging of hyperpolarized [13 C]urea in mouse liver

PURPOSE

To compare the apparent diffusion coefficient (ADC) of hyperpolarized (HP) [13 C,15 N]urea to the ADC of endogenous water in healthy and fibrotic mouse liver.

MATERIALS AND METHODS

ADC measurements for water and [13 C]urea were made in agarose phantoms at 14.1T. Next, the ADC of water and injected HP [13 C,15 N]urea were measured in eight CD1 mouse livers before and after induction of liver fibrosis using CCl4 . Liver fibrosis was quantified pathologically using the modified Brunt fibrosis score and compared to the measured ADC of water and urea.

RESULTS

In cell-free phantoms with 12.5% agarose, water ADC was nearly twice the ADC of urea (1.93 × 10-3 mm2 /s vs. 1.00 × 10-3 mm2 /s). The mean ADC values of water and [13 C,15 N]urea in healthy mouse liver (±SD) were nearly identical [(0.75 ± 0.11) × 10-3 mm2 /s and (0.75 ± 0.22) × 10-3 mm2 /s, respectively]. Mean water and [13 C,15 N]urea ADC values in fibrotic liver (±SD) were (0.84 ± 0.22) × 10-3 mm2 /s and (0.75 ± 0.15) × 10-3 mm2 /s, respectively. Neither water nor urea ADCs were statistically different in the fibrotic livers compared to baseline (P = 0.14 and P = 0.99, respectively). Water and urea ADCs were positively correlated at baseline (R2  = 0.52 and P = 0.045) but not in fibrotic livers (R2  = 0.23 and P = 0.23).

CONCLUSION

ADC of injected hyperpolarized urea in healthy liver reflects a smaller change as compared to free solution than ADC of water. This may reflect differences in cellular compartmentalization of the two compounds. No significant change in ADC of either water or urea were observed in relatively mild stages of liver fibrosis.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:141-151.

High-resolution 3D visualization of ductular proliferation of bile duct ligation-induced liver fibrosis in rats using x-ray phase contrast computed tomography

X-ray phase-contrast computed tomography (PCCT) can provide excellent image contrast for soft tissues with small density differences, and it is particularly appropriate for three-dimensional (3D) visualization of accurate microstructures inside biological samples. In this study, the morphological structures of proliferative bile ductules (BDs) were visualized without contrast agents via PCCT with liver fibrosis samples induced by bile duct ligation (BDL) in rats. Adult male Sprague-Dawley rats were randomly divided into three groups: sham operation group, 2-week and 6-week post-BDL groups. All livers were removed after euthanasia for a subsequent imaging. The verification of the ductular structures captured by PCCT was achieved by a careful head-to-head comparison with their corresponding histological images. Our experimental results demonstrated that PCCT images corresponded very well to the proliferative BDs shown by histological staining using cytokeratin 19 (CK19). Furthermore, the 3D density of proliferative BDs increased with the progression of liver fibrosis. In addition, PCCT accurately revealed the architecture of proliferative BDs in a 3D fashion, including the ductular ramification, the elongation and tortuosity of the branches, and the corrugations of the luminal duct surface. Thus, the high-resolution PCCT technique can improve our understanding of the characteristics of ductular proliferation from a new 3D perspective.

Comparison of T2, T1rho, and diffusion metrics in assessment of liver fibrosis in rats

PURPOSE

To evaluate the value of T₂ , T₁ rho, and diffusion metrics in assessment of liver fibrosis in rats.

MATERIALS AND METHODS

Liver fibrosis in a rat model (n = 72) was induced by injection of carbon tetrachloride (CCl₄ ) at 3T. T₂ , T₁ rho, and diffusion parameters (apparent diffusion coefficient (ADC), D_true ) via spin echo (SE) diffusion-weighted imaging (DWI) and stimulated echo acquisition mode (STEAM) DWI with three diffusion times (DT: 80, 106, 186 msec) were obtained in surviving rats with hepatic fibrosis (n = 52) and controls (n = 8). Liver fibrosis stage (F0-F6) was identified based on pathological results using the traditional liver fibrosis staging method for rodents. Nonparametric statistical methods and receiver operating characteristic (ROC) curve analysis were employed to determine the diagnostic accuracy.

RESULTS

Mean T₂ , T₁ rho, ADC, and D_true with DT = 186 msec correlated with the severity of fibrosis with r = 0.73, 0.83, -0.83, and -0.85 (all P < 0.001), respectively. The average areas under the ROC curve at different stages for T₁ rho and diffusion parameters (DT = 186 msec) were larger than those of T₂ and SE DWI (0.92, 0.92, and 0.92 vs. 0.86, 0.82, and 0.83). The corresponding average sensitivity and specificity for T₁ rho and diffusion parameters with a long DT were larger (89.35 and 88.90, 88.36 and 89.97, 90.16 and 87.13) than T₂ and SE DWI (90.28 and 79.93, 85.30 and 77.64, 78.21 and 82.41). The performances of T₁ rho and D_true (DT = 186 msec) were comparable (average AUC: 0.92 and 0.92).

CONCLUSION

Among the evaluated sequences, T₁ rho and STEAM DWI with a long DT may serve as superior imaging biomarkers for assessing liver fibrosis and monitoring disease severity.

LEVEL OF EVIDENCE

1 J. Magn. Reson. Imaging 2017;45:741-750.

Utility of Translocator Protein (18 kDa) as a Molecular Imaging Biomarker to Monitor the Progression of Liver Fibrosis

Hepatic fibrosis is the wound healing response to chronic hepatic injury caused by various factors. In this study, we aimed to evaluate the utility of translocator protein (18 kDa) (TSPO) as a molecular imaging biomarker for monitoring the progression of hepatic fibrosis to cirrhosis. Model rats were induced by carbon tetrachloride (CCl₄), and liver fibrosis was assessed. Positron emission tomography (PET) with N-benzyl-N-methyl-2-[7,8-dihydro-7-(2-[¹⁸F]fluoroethyl)-8-oxo-2-phenyl-9H-purin-9-yl]-acetamide ([¹⁸F]FEDAC), a radioprobe specific for TSPO, was used for noninvasive visualisation in vivo. PET scanning, immunohistochemical staining, ex vivo autoradiography, and quantitative reverse-transcription polymerase chain reaction were performed to elucidate the relationships among radioactivity uptake, TSPO levels, and cellular sources enriching TSPO expression in damaged livers. PET showed that uptake of radioactivity in livers increased significantly after 2, 4, 6, and 8 weeks of CCl₄ treatment. Immunohistochemistry demonstrated that TSPO was mainly expressed in macrophages and hepatic stellate cells (HSCs). TSPO-expressing macrophages and HSCs increased with the progression of liver fibrosis. Interestingly, the distribution of radioactivity from [¹⁸F]FEDAC was well correlated with TSPO expression, and TSPO mRNA levels increased with the severity of liver damage. TSPO was a useful molecular imaging biomarker and could be used to track the progression of hepatic fibrosis to cirrhosis with PET.

Endostar, a novel human recombinant endostatin, attenuates liver fibrosis in CCl4-induced mice

Decreasing hepatic fibrosis remains one of the major therapeutic challenges in hepatology. The present study aims to evaluate the effect of Endostar on both CCl4-induced liver fibrosis in mice and a hepatic stellate cell (HSC) line. Two main models were studied: (i) a liver fibrosis model was induced in BALB/c mice using CCl4 by intraperitoneal injection for six weeks. Six animal groups were studied: group 1: normal animals; group 2: CCl4-induced liver fibrosis; group 3: CCl4 + Endostar 20 mg/kg/d, six weeks; group 4: CCl4 + Endostar 10 mg/kg/d, six weeks; group 5: CCl4 + Endostar 20 mg/kg/d, four weeks; group 6: CCl4 + Endostar 10 mg/kg/d, four weeks corresponded to different Endostar doses and duration of administration. Liver fibrosis was evaluated by histopathological staining and liver hydroxyproline content. Expressions of collagen type I, α-smooth muscle actin ( α-SMA), TGF-β1 and VEGFR were measured by real-time polymerase chain reaction (PCR). (ii) A liver cell model. HSC-T6 cells were cultured with or without Endostar for 12 h or 24 h. Expressions of collagen type I, α-SMA, and TGF-β1 were measured by real-time PCR. Collagen I and transforming growth factor β1 (TGF-β1) contents in cell supernatant were measured by enzyme-linked immunosorbent assay. As compared to the group without Endostar, liver fibrosis scores and hydroxyproline content were decreased in both Endostar groups ( P < 0.05). Moreover, Endostar inhibited the hepatic expression of α-SMA, TGF-β1, Collagen-1, VEGFR1, and VEGFR2 mRNA ( P < 0.05). In the HSC-T6 cell line model, Endostar profoundly inhibited the expression of α-SMA, Collagen-1, and TGF-β1 mRNA. Expressions of Collagen-1 and TGF-β1 protein were decreased in the Endostar group as compared to the normal controls in the supernatant of HSC-T6 cells ( P < 0.05). Endostar decreased both liver fibrosis in CCl4-induced mice and collagen synthesis in HSCs in vitro. Therefore, this recombinant human endostatin is a promising compound for counteracting liver fibrosis.

PASS-predicted hepatoprotective activity of Caesalpinia sappan in thioacetamide-induced liver fibrosis in rats

The antifibrotic effects of traditional medicinal herb Caesalpinia sappan (CS) extract on liver fibrosis induced by thioacetamide (TAA) and the expression of transforming growth factor β1 (TGF-β1), α-smooth muscle actin (αSMA), and proliferating cell nuclear antigen (PCNA) in rats were studied. A computer-aided prediction of antioxidant and hepatoprotective activities was primarily performed with the Prediction Activity Spectra of the Substance (PASS) Program. Liver fibrosis was induced in male Sprague Dawley rats by TAA administration (0.03% w/v) in drinking water for a period of 12 weeks. Rats were divided into seven groups: control, TAA, Silymarin (SY), and CS 300 mg/kg body weight and 100 mg/kg groups. The effect of CS on liver fibrogenesis was determined by Masson's trichrome staining, immunohistochemical analysis, and western blotting. In vivo determination of hepatic antioxidant activities, cytochrome P450 2E1 (CYP2E1), and matrix metalloproteinases (MPPS) was employed. CS treatment had significantly increased hepatic antioxidant enzymes activity in the TAA-treated rats. Liver fibrosis was greatly alleviated in rats when treated with CS extract. CS treatment was noted to normalize the expression of TGF-β1, αSMA, PCNA, MMPs, and TIMP1 proteins. PASS-predicted plant activity could efficiently guide in selecting a promising pharmaceutical lead with high accuracy and required antioxidant and hepatoprotective properties.

Microcomputed tomography with diffraction-enhanced imaging for morphologic characterization and quantitative evaluation of microvessel of hepatic fibrosis in rats

Backgroud

Hepatic fibrosis can lead to deformation of vessel morphology and structure. In the present feasibility study, high-resolution computed tomography (CT) using diffraction-enhanced imaging (DEI) was used to represent three-dimensional (3D) vessel microstructures of hepatic fibrosis in rats and to differentiate different stages of hepatic fibrosis using qualitative descriptions and quantitative measurement of microvessels.

Material and Methods

Three typical specimens at different stages, i.e., mild, moderate and severe hepatic fibrosis, were imaged using DEI at 15 keV without contrast agents. The correspondence between DEI-CT images and histopathological findings was determined. The 3D visualizations from different stages of hepatic fibrosis were presented using DEI-CT. Additionally, Qualitative descriptions and quantitative evaluation of vessel features, such as vessel trend, vascular distortion deformation, thrombus formation and texture features on the inner wall of the vessel, were performed.

Results

DEI-CT produced high-resolution images of the vessel microstructures in hepatic fibrosis that corresponded to information on actual structures observed from the histological sections. Combined with the 3D visualization technique, DEI-CT enabled the acquisition of an accurate description of the 3D vessel morphology from different stages of hepatic fibrosis. Qualitative descriptions and quantitative assessment of microvessels demonstrated clear differences between the different stages of hepatic fibrosis. The thrombus inside the vessel of severe liver fibrosis was accurately displayed, and corresponding analysis can provide an exact measurement of vessel stenosis rate.

Conclusions

DEI-CT may allow morphologic descriptions and quantitative evaluation of vessel microstructures from different stages of hepatic fibrosis and can better characterize the various stages of fibrosis progression using high-resolution 3D vessel morphology.

Role for Krüppel-like transcription factor 11 in mesenchymal cell function and fibrosis

Krüppel-like factor 11 (KLF11) and the highly homologous KLF10 proteins are transcription factors originating from duplication of the Drosophila melanogaster ancestor cabut. The function of these proteins in epithelial cells has been previously characterized. In the current study, we report a functional role for KLF11 in mesenchymal cells and in mesenchymal cell dysfunction, namely, fibrosis, and subsequently perform a detailed cellular, molecular, and in vivo characterization of this phenomenon. We find that, in cultured mesenchymal cells, enhanced expression of KLF11 results in activated extracellular matrix pathways, including collagen gene silencing and matrix metalloproteinases activation without changes in tissue inhibitors of metalloproteinases. Combined, reporter and chromatin immunoprecipitation assays demonstrate that KLF11 interacts directly with the collagen 1a2 (COL1A2) promoter in mesenchymal cells to repress its activity. Mechanistically, KLF11 regulates collagen gene expression through the heterochromatin protein 1 gene-silencing pathway as mutants defective for coupling to this epigenetic modifier lose the ability to repress COL1A2. Expression studies reveal decreased levels of KLF11 during liver fibrogenesis after chemically induced injury in vivo. Congruently, KLF11^-/- mice, which should be deficient in the hypothesized anti-fibrogenic brake imposed by this transcription factor, display an enhanced response to liver injury with increased collagen fibril deposition. Thus, KLFs expands the repertoire of transcription factors involved in the regulation of extracellular matrix proteins in mesenchymal cells and define a novel pathway that modulates the fibrogenic response during liver injury.

Hepatoprotective Role of Ethanolic Extract of Vitex negundo in Thioacetamide-Induced Liver Fibrosis in Male Rats

The hepatoprotective activity of ethanolic extract from the leaves of Vitex negundo (VN) was conducted against thioacetamide- (TAA-) induced hepatic injury in Sprague Dawley rats. The therapeutic effect of the extract was investigated on adult male rats. Rats were divided into seven groups: control, TAA, Silymarin (SY), and VN high dose and low dose groups. Rats were administered with VN extract at two different doses, 100 mg/kg and 300 mg/kg body weight. After 12 weeks, the rats administered with VN showed a significantly lower liver to body weight ratio. Their abnormal levels of biochemical parameters and liver malondialdehyde were restored closer to the normal levels and were comparable to the levels in animals treated with the standard drug, SY. Gross necropsy and histopathological examination further confirmed the results. Progression of liver fibrosis induced by TAA in rats was intervened by VN extract administration, and these effects were similar to those administered with SY. This is the first report on hepatoprotective effect of VN against TAA-induced liver fibrosis.

Antifibrotic effects of a recombinant adeno-associated virus carrying small interfering RNA targeting TIMP-1 in rat liver fibrosis

Elevated tissue inhibitor of metalloproteinase 1 (TIMP-1) expression contributes to excess production of extracellular matrix in liver fibrosis. Herein, we constructed a recombinant adeno-associated virus (rAAV) carrying siRNA of the TIMP-1 gene (rAAV/siRNA-TIMP-1) and investigated its effects on liver fibrosis in rats. Two models of rat liver fibrosis, the carbon tetrachloride and bile duct ligation models, were treated with rAAV/siRNA-TIMP-1. In the carbon tetrachloride model, rAAV/siRNA-TIMP-1 administration attenuated fibrosis severity, as determined by histologic analysis of hepatic collagen accumulation, hydroxyproline content, and concentrations of types I and III collagen in livers and sera. Levels of mRNA and active matrix metalloproteinase (MMP) 13 were elevated, whereas levels of mRNA and active MMP-2 were decreased. Moreover, a marked decrease was noted in the expression of α-smooth muscle actin, a biomarker of activated hepatic stellate cells (HSCs), and transforming growth factor-β1, critical for the development of liver fibrosis. Similarly, rAAV/siRNA-TIMP-1 treatment significantly alleviated bile duct ligation-induced liver fibrosis. Furthermore, this treatment dramatically suppressed TIMP-1 expression in HSCs from both model rats. These data indicate that the administration of rAAV/siRNA-TIMP-1 attenuated liver fibrosis by directly elevating the function of MMP-13 and diminishing activated HSCs. It also resulted in indirect decreased expression of type I collagen, MMP-2, and transforming growth factor-β1. In conclusion, rAAV/siRNA-TIMP-1 may be an effective antifibrotic gene therapy agent.

Liver precursor cells increase hepatic fibrosis induced by chronic carbon tetrachloride intoxication in rats

Hepatic fibrosis, the major complication of virtually all types of chronic liver damage, usually begins in portal areas, and its severity has been correlated to liver progenitor cells (LPC) expansion from periportal areas, even if the primary targets of injury are intralobular hepatocytes. The aim of this study was to determine the potential fibrogenic role of LPC, using a new experimental model in which rat liver fibrosis was induced by chronic carbon tetrachloride (CCl(4)) administration for 6 weeks, in combination with chronic acetylaminofluorene treatment (AAF), which promotes activation of LPC compartment. Treatment with CCl(4) alone caused a significant increase in serum transaminase activity as well as liver fibrosis initiating around central veins and leading to formation of incomplete centro-central septa with sparse fibrogenic cells expressing α-smooth muscle actin (αSMA). In AAF/CCl(4)-treated animals, the fibrogenic response was profoundly worsened, with formation of multiple porto-central bridging septa leading to cirrhosis, whereas hepatocellular necrosis and inflammation were similar to those observed in CCl(4)-treated animals. Enhanced fibrosis in AAF/CCl(4) group was accompanied by ductule forming LPC expanding from portal areas, αSMA-positive cells accumulation in the fibrotic areas and increased expression of hepatic collagen type 1, 3 and 4 mRNA. Moreover, CK19-positive LPC expressed the most potent fibrogenic cytokine transforming growth factor-β (TGFβ) without any expression of αSMA, desmin or fibroblast-specific protein-1, demonstrating that LPC did not undergo an epithelial-mesenchymal transition. In this new experimental model, LPC, by expressing TGFβ, contributed to the accumulation of αSMA-positive myofibroblasts in the ductular reaction leading to enhanced fibrosis but also to disease progression and to a fibrotic pattern similar to that observed in humans.

Predicting in vivo anti-hepatofibrotic drug efficacy based on in vitro high-content analysis

Background/Aims

Many anti-fibrotic drugs with high in vitro efficacies fail to produce significant effects in vivo. The aim of this work is to use a statistical approach to design a numerical predictor that correlates better with in vivo outcomes.

Methods

High-content analysis (HCA) was performed with 49 drugs on hepatic stellate cells (HSCs) LX-2 stained with 10 fibrotic markers. ∼0.3 billion feature values from all cells in >150,000 images were quantified to reflect the drug effects. A systematic literature search on the in vivo effects of all 49 drugs on hepatofibrotic rats yields 28 papers with histological scores. The in vivo and in vitro datasets were used to compute a single efficacy predictor (E_predict).

Results

We used in vivo data from one context (CCl₄ rats with drug treatments) to optimize the computation of E_predict. This optimized relationship was independently validated using in vivo data from two different contexts (treatment of DMN rats and prevention of CCl₄ induction). A linear in vitro-in vivo correlation was consistently observed in all the three contexts. We used E_predict values to cluster drugs according to efficacy; and found that high-efficacy drugs tended to target proliferation, apoptosis and contractility of HSCs.

Conclusions

The E_predict statistic, based on a prioritized combination of in vitro features, provides a better correlation between in vitro and in vivo drug response than any of the traditional in vitro markers considered.

N-methyl-4-isoleucine cyclosporine attenuates CCl -induced liver fibrosis in rats by interacting with cyclophilin B and D

BACKGROUND AND AIM

N-methyl-4-isoleucine cyclosporine (NIM811), a new analogue of cyclosporine A, can inhibit collagen deposition in vitro and reduce liver necrosis in a bile-duct-ligation animal model. However, whether NIM811 effects on CCl(4) -induced rat liver fibrosis, and the related mechanism has not been determined.

METHODS

A liver fibrosis model was induced in Wistar rats using CCl(4) for 6 weeks. Meanwhile, two different doses of NIM811 (low-dose 10 mg/kg and high-dose 20 mg/kg) were given to the CCl(4) -treated rats. Liver fibrosis was then evaluated according to histopathological scoring and liver hydroxyproline content. Serum alanine aminotransferase, aspartate aminotransferase and albumin levels, expression of matrix metalloproteinase-13, tissue inhibitor of metalloproteinase-1, α-smooth muscle actin and cyclophilin B and D in liver tissue were determined. Cyclophilin B and D were also studied in an hepatic stellate cell line.

RESULTS

Hydroxyproline content was decreased in both NIM811 groups compared with the model (P < 0.05). Liver necrosis and fibrosis were also attenuated in the NIM811 groups. NIM811 suppressed the expression of tissue inhibitor of metalloproteinase-1, transforming growth factor beta mRNA and α-smooth muscle actin protein in liver tissue. Expression of cyclophilin B in the fibrosis model was increased compared with the normal group (P < 0.05), and was decreased significantly in the low-dose NIM811 treatment group (P < 0.05), which indicated that cyclophilin B might have a profibrotic effect. In vitro studies revealed that cyclophilin B and/or D knockout were associated with collagen inhibition.

CONCLUSIONS

NIM811 attenuates liver fibrosis in a CCl(4)-induced rat liver fibrosis model, which may be related to binding with cyclophilin B and D.

Chronic hepatitis, hepatic dysplasia, fibrosis, and biliary hyperplasia in hamsters naturally infected with a novel Helicobacter classified in the H. bilis cluster

We recently described helicobacter-associated progressive, proliferative, and dysplastic typhlocolitis in aging (18- to 24-month-old) Syrian hamsters. Other pathogens associated with typhlocolitis in hamsters, Clostridium difficile, Lawsonia intracellularis, and Giardia spp., were not indentified. The presence of Helicobacter genus-specific DNA was noted by PCR in cecal and paraffin-embedded liver samples from aged hamsters by the use of Helicobacter-specific PCR primers. By 16S rRNA analysis, the Helicobacter sp. isolated from the liver tissue was identical to the cecal isolates from hamsters. The six hamster 16S rRNA sequences form a genotypic cluster most closely related to Helicobacter sp. Flexispira taxon 8, part of the Helicobacter bilis/H. cinaedi group. Livers from aged helicobacter-infected hamsters showed various stages of predominantly portocentric and, to a lesser extent, perivenular fibrosis. Within nodules, there was cellular atypia consistent with nodular dysplasia. The livers also exhibited a range of chronic active portal/interface and lobular inflammation, with significant portal hepatitis being present. The inflammation was composed of a mixture of lymphocytes, neutrophils, and macrophages, indicative of its chronic-active nature in these aged hamsters infected with Helicobacter spp. The isolation of novel Helicobacter spp., their identification by PCR from the diseased livers of aged hamsters, and their taxonomic classification as belonging to the Helicobacter bilis cluster strengthen the argument that H. bilis and closely related Helicobacter spp. play an etiological role in hepatobiliary disease in both animals and humans.

Pirfenidone inhibits carbon tetrachloride- and albumin complex-induced liver fibrosis in rodents by preventing activation of hepatic stellate cells

1. Pirfenidone (PFD; 5-methyl-1-phenyl-2(1H)-pyridone) is an effective and novel agent with antifibrotic and anti-inflammatory properties. In the present study, we investigated the antifibrotic effects of PFD on experimental liver fibrosis models in rodents and the possible underlying molecular mechanisms. 2. Liver fibrosis was induced by carbon tetrachloride (CCl(4)) in BALB/c mice. Pirfenidone (250 mg/kg) and silymarin (50 mg/kg) were given to different groups of rats by gastric gavage for 4 weeks. Pirfenidone significantly attenuated fibrosis severity, as determined by histopathological scores and hydroxyproline levels in liver tissue, by 49.8 and 44.9%, respectively, compared with the CCl(4)-treated group. The antifibrotic effects of PFD were significantly greater than those of silymarin, as indicated by a decrease of 23.5 and 24.8% in histopathological scores and hydroxyproline levels, respectively. 3. Liver fibrosis was also induced by albumin antigen-antibody complex in Wistar rats, which were then treated with the same doses of PFD and silymarin for 8 weeks. Pirfenidone significantly reduced the degree of fibrosis compared with CCl(4)-treated rats (by 45.0 and 51.0% as determined by histopathological scores and hydroxyproline levels in liver tissue, respectively). The antifibrotic effects of PFD were comparable to those of silymarin. 4. The effects of PFD on the expression of extracellular matrix-associated genes in human hepatic stellate cells (the LX-2 cell line) were measured by real-time quantitative polymerase chain reaction. LX-2 cells were treated with or without 100 micromol/L or 1 mmol/L PFD for 24 h. Pirfenidone significantly inhibited the expression of a-smooth muscle actin and Type I collagen in 8 ng/mL transforming growth factor-beta1- or 5% fetal bovine serum-activated LX-2 cells in a dose-dependent manner. 5. In conclusion, the results of the present study demonstrate that PFD is effective in ameliorating fibrogenesis induced by CCl(4) in mice and by the albumin complex in rats. These effects were mediated mainly via inhibition of the activation of hepatic stellate cells, as well as antifibrotic actions (i.e. inhibition of collagen synthesis) of PFD.