Liver stellate cells in chronic viral hepatitis: the effect of interferon therapy

Dendropanoxide, a Triterpenoid from Dendropanax morbifera, Ameliorates Hepatic Fibrosis by Inhibiting Activation of Hepatic Stellate Cells through Autophagy Inhibition

Hepatic fibrosis results from chronic liver damage and is characterized by excessive accumulation of extracellular matrix (ECM). In this study, we showed that dendropanoxide (DPX), isolated from Dendropanax morbifera, had anti-fibrotic effects on hepatic fibrosis by inhibiting hepatic stellate cell (HSC) activation. DPX suppressed mRNA and protein expression of α-SMA, fibronectin, and collagen in activated HSCs. Moreover, DPX (40 mg/kg) treatment significantly lowered levels of liver injury markers (aspartate aminotransferase and alanine transaminase), expression of fibrotic markers, and deposition of ECM in a carbon tetrachloride-induced mouse model. Anti-fibrotic effects of DPX were comparable to those of silymarin in a hepatic fibrosis mouse model. As a possible mechanism of anti-fibrotic effects, we showed that DPX inhibited autophagosome formation (LC3B-II) and degradation of p62, which have important roles in HSC activation. These findings suggest that DPX inhibits HSC activation by inhibiting autophagy and can be utilized in hepatic fibrosis therapy.

Desmin- and vimentin-mediated hepatic stellate cell-targeting radiotracer 99mTc-GlcNAc-PEI for liver fibrosis imaging with SPECT

Extracellular matrix (ECM) accumulation in liver fibrosis is caused by the activation of hepatic stellate cells (HSCs). The goal of this study was to develop a ^99mTc-labeled N-acetylglucosamine (GlcNAc) that specifically interacts with desmin and vimentin expressed on activated HSCs to monitor the progression and prognosis of liver fibrosis using single-photon emission computed tomography (SPECT) imaging.

Methods: GlcNAc-conjugated polyethylenimine (PEI) was first prepared and radiolabeled with ^99mTc. Noninvasive SPECT imaging with ^99mTc-GlcNAc-PEI was used to assess liver fibrosis in a carbon tetrachloride (CCl₄) mouse model. The liver uptake value (LUV) of ^99mTc-GlcNAc-PEI was measured by drawing the region of interest (ROI) of the whole liver as previously suggested. The LUV of the CCl₄ groups was compared with that of the olive oil group. Next, we estimated the correlation between the results of SPECT imaging and physiological indexes. After treatment with clodronate liposome, the LUV of ^99mTc-GlcNAc-PEI in fibrotic mice was compared with that in control mice.

Results:^99mTc-GlcNAc-PEI is a hydrophilic compound with high radiochemical purity (>98%) and good stability. It could specifically target desmin and vimentin on the surface of activated HSCs with high affinity (the K_d values were 53.75 ± 9.50 nM and 20.98 ± 3.56 nM, respectively). The LUV of ^99mTc-GlcNAc-PEI was significantly different between the CCl₄ and control groups as early as 4 weeks of CCl₄ administration (3.30 ± 0.160 vs 2.34 ± 0.114%/cc; P ˂ 0.05). There was a strong correlation between the LUV and Sirius Red quantification (R = 0.92, P ˂ 0.001). Compared with control, clodronate liposome treatment reduced the LUV of ^99mTc-GlcNAc-PEI (4.62 ± 0.352 vs 2.133 ± 0.414%/cc; P ˂ 0.05).

Conclusion:^99mTc-GlcNAc-PEI SPECT/CT was useful in assessing liver fibrosis and monitoring the treatment response.

Small-Animal SPECT/CT of the Progression and Recovery of Rat Liver Fibrosis by Using an Integrin αvβ3-targeting Radiotracer

PURPOSE

To assess the potential utility of an integrin αvβ3-targeting radiotracer, technetium 99m-PEG4-E[PEG4-cyclo(arginine-glycine-aspartic acid-D-phenylalanine-lysine)]2 ((99m)Tc-3PRGD2), for single photon emission computed tomography (SPECT)/computed tomography (CT) for monitoring of the progression and prognosis of liver fibrosis in a rat model.

MATERIALS AND METHODS

All animal experiments were performed by following the protocol approved by the institutional animal care and use committee. (99m)Tc-3PRGD2 was prepared and longitudinal SPECT/CT was performed to monitor the progression (n = 8) and recovery (n = 5) of liver fibrosis induced in a rat model by means of thioacetamide (TAA) administration. The mean liver-to-background radioactivity per unit volume ratio was analyzed for comparisons between the TAA and control (saline) groups at different stages of liver fibrosis. Data were compared by using Student t and Mann-Whitney tests. Results:of SPECT/CT were compared with those of ex vivo biodistribution analysis (n = 5).

RESULTS

Accumulation of (99m)Tc-3PRGD2 in the liver increased in proportion to the progression of fibrosis and TAA exposure time; accumulation levels were significantly different between the TAA and control groups as early as week 4 of TAA administration (liver-to-background ratio: 32.30 ± 3.39 vs 19.01 ± 3.31; P = .0002). Results of ex vivo immunofluorescence staining demonstrated the positive expression of integrin αvβ3 on the activated hepatic stellate cells, and the integrin αvβ3 levels in the liver corresponded to the results of SPECT/CT (R(2) = 0.75, P < .0001). (99m)Tc-3PRGD2 uptake in the fibrotic liver decreased after antifibrotic therapy with interferon α2b compared with that in the control group (relative liver-to-background ratio: 0.45 ± 0.05 vs 1.01 ± 0.05; P < .0001) or spontaneous recovery (relative liver-to-background ratio: 0.56 ± 0.06 vs 1.01 ± 0.05; P < .0001).

CONCLUSION

(99m)Tc-3PRGD2 SPECT/CT was successfully used to monitor the progression and recovery of liver fibrosis and shows potential applications for noninvasive diagnosis of early stage liver fibrosis.

Slight activation of nuclear factor kappa-B is associated with increased hepatic stellate cell apoptosis in human schistosomal fibrosis

To investigate the relationship between NF-kappaB activation and hepatic stellate cell (HSC) apoptosis in hepatosplenic schistosomiasis, hepatic biopsies from patients with Schistosoma mansoni-induced periportal fibrosis, hepatitis C virus-induced cirrhosis, and normal liver were submitted to alpha-smooth muscle actin (alpha-SMA) and NF-kappaB p65 immunohistochemistry, as well as to NF-kappaB Southwestern histochemistry and TUNEL assay. The numbers of alpha-SMA-positive cells and NF-kappaB- and NF-kappaB p65-positive HSC nuclei were reduced in schistosomal fibrosis relative to liver cirrhosis. In addition, increased HSC NF-kappaB p65 and TUNEL labeling was observed in schistosomiasis when compared to cirrhosis.These results suggest a possible relationship between the slight activation of the NF-kappaB complex and the increase of apoptotic HSC number in schistosome-induced fibrosis, taking place to a reduced HSC number in schistosomiasis in relation to liver cirrhosis. Therefore, the NF-kappaB pathway may constitute an important down-regulatory mechanism in the pathogenesis of human schistosomiasis mansoni, although further studies are needed to refine the understanding of this process.

Serum fibrosis marker levels decrease after successful antiviral treatment in chronic hepatitis C patients with advanced fibrosis

BACKGROUND & AIMS

Serum fibrosis marker levels during the lead-in treatment phase of patients enrolled in the Hepatitis C Antiviral Long-term Treatment against Cirrhosis (HALT-C) trial were determined.

METHODS

Week 0, 24, 48, and 72 serum samples were analyzed for YKL-40, tissue inhibitor of matrix metalloproteinase-1, amino-terminal peptide of type III procollagen (PIIINP), and hyaluronic acid (HA) levels. All 456 chronic hepatitis C (CHC) patients received peginterferon alfa 2a and ribavirin for 24 to 48 weeks.

RESULTS

Mean age was 49.2 years, 71% were male, and 39% had cirrhosis. Lower pretreatment serum YKL-40, tissue inhibitor of matrix metalloproteinase-1, PIIINP, and HA levels were associated significantly with week-20 virologic response (P < .0001). In multivariate analysis, non-1 CHC genotype, non-black race, prior interferon monotherapy, and lower baseline serum aspartate aminotransferase/alanine aminotransferase levels and log(10)YKL-40 levels were associated independently with week-20 virologic response. Statistically significant declines in all marker levels were observed at week 72 compared with baseline in the 81 patients with a sustained virologic response, but not in the 72 patients with breakthrough or relapse. At weeks 24 and 48, significant increases were observed in serum PIIINP and HA levels compared with baseline in virologic responders and nonresponders (P < .0001).

CONCLUSIONS

Pretreatment YKL-40 levels are an independent predictor of initial virologic response to peginterferon and ribavirin treatment. Levels of all 4 serum fibrosis markers decreased significantly in the SVR patients, consistent with reduced hepatic fibrogenesis. Measuring serum fibrosis marker levels before and after antiviral therapy may provide important prognostic information in CHC patients.

Glial fibrillary acidic protein as an early marker of hepatic stellate cell activation in chronic and posttransplant recurrent hepatitis C

Activated alpha-smooth muscle actin (alpha-SMA)-positive hepatic stellate cells (HSCs) are pericytes responsible for fibrosis in chronic liver injury. The glial fibrillary acidic protein (GFAP), commonly expressed by astrocytes in the central nervous system, is expressed in vivo in the liver in a subpopulation of quiescent stellate cells. In the rat, increased GFAP expression in the acute response to injury and down-regulation in the chronic response have been observed, whereas reports concerning GFAP expression in human liver are still conflicting. We investigated the utility of GFAP compared to alpha-SMA as an immunohistochemical marker of early activated HSCs in chronic and posttransplant recurrent hepatitis C and correlated GFAP expression with vascular remodeling and fibrosis progression. With immunohistochemistry and a semiquantitative scoring system, the expression of GFAP and alpha-SMA in HSCs and the microvessel density were analyzed in biopsies from normal livers obtained from cadaveric donors [donor liver (DL); n = 21] and from livers from posttransplant hepatitis C virus recurrent hepatitis (HCV-PTR) patients (n = 19), hepatitis C virus chronic hepatitis (HCV-CH) patients, (n = 12), and hepatitis C virus cirrhosis (HCV-C) patients (n = 16). The percentage of alpha-SMA-positive HSCs was significantly higher in the HCV-PTR, HCV-CH, and HCV-C groups compared to the DL group (P < 0.01). The percentage of GFAP-positive HSCs was significantly higher in the HCV-PTR group compared to the DL, HCV-C (P < 0.01), and HCV-CH (P < 0.05) groups and in the HCV-CH group compared to the DL group (P < 0.01), inversely correlating with the extent of fibrosis and microvessel density (P < 0.01). In the HCV-PTR group, the percentage of GFAP-positive HSCs correlated with fibrosis progression (P < 0.01). In conclusion, GFAP could represent a useful marker of early activation of HSCs in HCV-CH and seems to predict fibrosis progression in HCV-PTR.

Comparative studies on expression of alpha-smooth muscle actin in hepatic stellate cells in chronic hepatitis B and C

BACKGROUND/AIMS

Chronic hepatitis B and hepatitis C are common causes of liver fibrosis and cirrhosis. We performed a comparative study on the expression of alpha-smooth muscle actin (alpha-SMA) in hepatic stellate cells (HSCs), a marker of HSC activation, in patients with chronic hepatitis B and hepatitis C.

PATIENTS AND METHODS

Using immunohistochemistry and a semi-quantitative scoring method, the expression of alpha-SMA in HSCs was studied in patients with chronic hepatitis B (n = 50) and hepatitis C (n = 50). The HSC activation index was correlated with age, sex, AST, ALT, viral genotype, viral titers, degrees of hepatic steatosis, necroinflammatory grades and fibrotic stages.

RESULTS

The HSC activation index correlated significantly (P < 0.05) with necroinflmmatory grades and fibrotic stages in chronic hepatitis B or hepatitis C. Besides, the HSC activation index also correlated significantly (P < 0.05) with hepatic steatosis and marginally significantly (P = 0.08) with serum viral titers in chronic hepatitis C. There was no significant difference in biochemical and histological activities between patients with hepatitis B and hepatitis C, but the latter had a significantly higher HSC activation index than the former. Multiple regression analysis in all 100 patients showed that the HSC activation index correlated significantly (P < 0.05) with necroinflammatory grades, fibrotic stages and hepatitis C (versus hepatitis B).

CONCLUSION

In chronic viral hepatitis, the HSC activation index correlated significantly and independently with necroinflammation and fibrosis. Additionally, the HSC activation index was significantly higher in patients with chronic hepatitis C. These data may be compatible with the postulation that hepatitis C virus can directly activate HSCs.

Hepatic stellate cells and liver fibrosis

Substantial evidence now exists to recognize hepatic stellate cells (HSCs) as the main matrix-producing cells in the process of liver fibrosis. Liver injury of any etiology will ultimately lead to activation of HSCs, which undergo transdifferentiation to fibrogenic myofibroblast-like cells. Quantitative analysis of HSC activation by immunohistochemistry has been shown to be useful in predicting the rate of progression of liver fibrosis in some clinical situations. In the activation process, transforming growth factor beta is thought to be the main mediator of fibrogenesis and platelet-derived growth factor is the major inducer of HSC proliferation. Different platelet-derived growth factor and transforming growth factor beta inhibitors have been shown to effectively prevent liver fibrosis in animal models and represent promising therapeutic agents for humans.

Liver cirrhosis and hepatic stellate cells

The cirrhosis represents the final stage of several chronic hepatic diseases and it is characterized by the presence of fibrosis and morphologic conversion from the normal hepatic architecture into structurally abnormal nodules. In the evolution of the disease there is loss of the normal vascular relationship and portal hypertension. There are also regenerative hepatocellular alterations that become more prominent with the progression of the disease. The liver transplantation continues to be the only therapeutic option in cases of disease in terminal phase. The hepatic stellate cells (HSC) are perisinusoidal cells that store vitamin A and produce growth factors, citocins, prostaglandins and other bioactive substances. They can suffer an activation process that convert them to cells with a phenotype similar to myofibroblasts. When activated, they present increased capacity of proliferation, mobility, contractility and synthesis of collagen and other components of extracellular matrix. They possess cytoplasmic processes adhered to sinusoids and can affect the sinusoidal blood flow. HSC are important in pathogenesis of fibrosis and portal hypertension.

Pegylated interferon-alpha plus taurine in treatment of rat liver fibrosis

AIM: To investigate the antifibrotic effects of peginterferon-alpha 2b and taurine on oxidative stress markers and hepatocellular apoptosis.

METHODS: Sixty rats with CCl4-induced liver fibrosis were divided into 4 groups (n = 15). Group 1 was left for spontaneous recovery (SR). Groups 2-4 received peginterferon-alpha 2b, taurine, and their combination, respectively, for four weeks. Histological fibrosis scores, histomorphometric analysis, tissue hydroxyproline, tissue MDA, GPx and SOD activities were determined. Activated stellate cells and hepatocellular apoptosis were also evaluated.

RESULTS: The degree of fibrosis decreased in all treatment groups compared to spontaneous recovery group. Taurine alone and in combination with peginterferon-alpha 2b reduced oxidative stress markers, but peginterferon-alpha 2b alone did not. Apoptotic hepatocytes and activated stellate cells were higher in groups 2-4 than in group 1. Combined taurine and peginterferon-alpha 2b further reduced fibrosis and increased activated stellate cell apoptosis, but could not improve oxidative stress more than taurine alone.

CONCLUSION: Peginterferon-alpha 2b exerts anti-fibrotic effects on rat liver fibrosis. It seems ineffective against oxidative stress in vivo. Peginterferon-alpha 2b in combination with taurine seems to be an antifibrotic strategy.

Diagnosis of hepatic fibrosis in patients with chronic hepatitis C

Chronic hepatitis C (HCV) infection leads to the development of hepatic fibrosis. No single test for diagnosing liver fibrosis is completely optimal. The ability to assess the extent and progression of fibrosis is important in the clinical setting, especially in the context of current treatments and therapeutic trials. More accurate and noninvasive methods to diagnose and monitor fibrosis are needed, because these trials will require serial evaluations of liver fibrosis to assess a compound's antifibrotic effect.

Effects of interferon plus ribavirin treatment on NF-kappaB, TGF-beta1, and metalloproteinase activity in chronic hepatitis C

Little is known about the cellular and molecular mechanisms underlying the effects of anti-viral therapy on the regression of liver inflammation and fibrosis in chronic hepatitis C. The aim of this study was to evaluate the effects of interferon alpha and ribavirin in combination therapy on the tissue expression of nuclear-factor kB (NF-kappaB) (a transcription factor coordinating the expression of stress genes involved in immune response and inflammation), of the polypeptide transforming growth factor beta-1 (TGF-beta1) and matrix metalloproteinases 1 (MMP-1) (both of which play an important part in the pathological process of liver fibrogenesis), and on the serum levels of soluble TGF-beta1, tissue inhibitors of metalloproteinases (TIMP)-1, and active endogenous MMP-2 and MMP-9 in paired (pre- and post-treatment) liver biopsy and serum samples of subjects with chronic hepatitis C. Serum levels of TGF-beta1, TIMP-1, MMP-2, and MMP-9 were evaluated by enzyme-linked immunosorbent assay. Liver expression of muscle-specific alpha-actin, NF-kappaB, TGF-beta1, and MMP-1 was studied immunohistochemically using commercially available mono- and polyclonal antisera in an avidin-biotin complex method. Combination therapy induced a reduction in the liver expression of TGF-beta and NF-kappaB and an increased expression of MMP-1, regardless of the virological response to the treatment. The greater expression of MMP-1 and lesser expression of NF-kappaB were both associated with an improvement in fibrosis score. These effects paralleled the significant increase in soluble MMP-9/TIMP-1 ratio in post-therapy sera. Combination therapy with interferon and ribavirin affects the tissue expression of TGF-beta-1 and NF-kappaB and favors metalloproteinase activity, and may thereby modulate hepatic fibrogenetic events.

Hepatic Stellate Cells in Biopsies From Liver Allografts With Acute Rejection

BACKGROUND

[corrected] Hepatic stellate cells (HSCs) are nonparenchymal elements that play a major role in fibrogenesis due to various pathologies. HSCs are easily activated by certain injuries, which produce contraction and relaxation of HSCs, resulting in hepatic microcirculatory disturbances. The present study sought to analyze the expression of alpha-smooth muscle actin (alpha-SMA) positive HSCs in liver allografts during acute rejection episodes (ARE), determining whether it was related to the pathogenesis of this immune response.

MATERIALS AND METHODS

Using immunohistochemistry and a semiquantitative scoring system, the expression of alpha-SMA in HSCs was analyzed in liver allografts with ARE (group 1, n = 64) or without ARE (group 2, n = 20). Normal liver tissue from transplant donors (group 3, n = 53) served as the control materials.

RESULTS

Significantly more alpha-SMA positive HSCs were found in group 2 than in the other two groups (P < .05). The minimal difference observed between groups 1 and 3 was not statistically significant. As well, no statistical association was found between expression of alpha-SMA and the clinical parameters of age, gender, etiology of liver failure, donor type (partial or whole), posttransplantation period, and liver function tests.

CONCLUSIONS

While these results represent preliminary findings, it may be possible that HSC expression is a protective mechanism during ARE in hepatic allograft patients. If this is true, enhanced expression of this protein may mitigate ARE in liver allograft patients.

Hepatic stellate cells in human schistosomiasis mansoni: a comparative immunohistochemical study with liver cirrhosis

This study compares the populations of liver mesenchymal cells (LMCs) and their proliferative activity in schistosomal periportal fibrosis and in hepatitis C virus-induced cirrhosis. LMCs were evaluated by immunohistochemical double staining for proliferating cell nuclear antigen (PCNA) and alpha-smooth muscle actin (alpha-SMA) or glial fibrillary acid protein (GFAP) in liver biopsies from humans with schistosomal fibrosis (n=40), hepatitis C virus-induced cirrhosis (n=20), and normal controls (n=20). The number of LMCs was found to be higher in schistosomal fibrosis than in the normal liver, but lower than in cirrhosis. alpha-SMA- and GFAP-positive cells were increased in both diseases, but more so in cirrhosis. In cirrhotic liver, alpha-SMA-positive cells were highly predominant in relation to GFAP-positive cells. However, there was an inverted ratio between these cells in schistosomiasis as compared to cirrhosis. The PCNA labeling index was higher in alpha-SMA-positive cells than in GFAP-positive cells, and did not differ between pipe-stem fibrosis and liver cirrhosis regarding alpha-SMA- or GFAP-positive cells. The predominance of GFAP-positive cells observed in schistosomiasis suggests that hepatic stellate cells (HSCs) have a major role in connective tissue deposition in the human schistosomal liver. On the other hand, the smaller number of LMCs in schistosomal fibrosis in comparison to liver cirrhosis may be related to mild and limited injury due to the schistosomal egg-induced inflammatory response. The granulomatous inflammation around Schistosoma mansoni eggs appears to mobilize and activate a reduced number of mesenchymal cells in comparison to the scattered necro-inflammatory reaction produced by the hepatitis C virus.

Rat liver fibrosis regresses better with pegylated interferon alpha2b and ursodeoxycholic acid treatments than spontaneous recovery

BACKGROUND/AIMS

Fibrosis and cirrhosis are common complications of chronic liver diseases. An imbalance between fibrogenesis and fibrolysis results in scarring of the liver parenchyma. We aimed to investigate the possible antifibrotic effectiveness of a newly modified interferon molecule peginterferon alpha2b (PEG-IFNalpha2b) which has better antiviral activity, and ursodeoxycholic acid (UDCA).

METHODOLOGY

Liver fibrosis was established on 60 male Sprague Dawley rats with CCl4 in 12 weeks. After cessation of CCl4 Group I was left for spontaneous recovery. Group II was treated with PEG-IFN 1.5 microg/kg/week, Group III with UDCA 25 mg/kg/day and Group IV with combination of both drugs. All rats were killed at week 16. Histopathologic fibrosis scores, tissue hydroxyproline, TIMP-1 and MMP-13 levels were determined. Hepatic stellate cell apoptosis was detected by dual staining with TUNEL technique and anti-alpha smooth muscle actin.

RESULTS

Fibrosis scores were lower in Group II, III and IV than Group I (p<0.05 for group I vs. II and III; p<0.01 for group I vs. IV). Tissue hydroxyproline levels were significantly decreased in Group II, III and IV when compared to Group I (p<0.05 for group I vs. II, p<0.01 for group I vs. III and IV). Lower liver TIMP-1 and higher MMP-13 levels were measured in Group II, III, and Group IV than Group I (p<0.01 for TIMP-1 and p<0.01, for MMP). Activated HSC apoptosis was significantly increased in Group II, III and IV when compared to Group I (p<0.01, for all). There was significantly higher apoptosis in Group II than Group III and IV (p<0.01).

CONCLUSION

Treatment with both PEG-IFNalpha2b and UDCA improved CCl4 induced rat liver fibrosis. Significantly higher effects were obtained using these agents in combination.

Early hepatic stellate cell activation predicts severe hepatitis C recurrence after liver transplantation

Only a subset of hepatitis C virus (HCV)-infected patients develop progressive hepatic fibrosis after liver transplantation (LT). Hepatic stellate cell (HSC) activation is a pivotal step in hepatic fibrosis and precedes clinically apparent fibrosis. We determined whether early HSC activation, measured in 4-month protocol post-LT biopsies, is predictive of subsequent development of more histologically severe recurrence of HCV. Early (4 month) post-LT HSC activation, as measured by alpha-smooth muscle actin (alpha-SMA) staining, was determined in liver biopsies from recipients with severe (fibrosis score > or = 2, n = 13) and with mild (fibrosis score of 0, n = 13) recurrence of HCV at one-year post-LT. Immunohistochemical staining for alpha-smooth muscle actin (alpha-SMA) was used to generate HSC activation scores (regional and total). Total HSC activation scores at 4 months were similar in patients with severe and mild HCV recurrence (3.9 +/- 2.0 vs. 2.7 +/- 2.2, P = 0.2). Regional HSC activation, assessed as parenchymal (zones 1, 2, and 3) or mesenchymal (portal tracts and fibrous septa), was different between the study groups, with higher mesenchymal scores predictive of progression. No patients in the mild recurrence group had detectable mesenchymal alpha-SMA staining vs. 46% (6/13) of patients with severe recurrence (P < 0.01). Mesenchymal activation of HSC had a specificity and positive predictive value of 100% for development of progressive fibrosis in liver allografts of patients with hepatitis C. In conclusion, early activation of mesenchymal HSCs is a marker for progressive fibrosis in patients with hepatitis C post-LT and may help select patients who would benefit from HCV or HSC-targeted therapy.

The value of alpha-SMA in the evaluation of hepatic fibrosis severity in hepatitis B infection and cirrhosis development: a histopathological and immunohistochemical study

AIMS

To investigate the value of alpha-smooth muscle actin (alpha-SMA), an indicator of stellate cell activation, in predicting fibrosis in chronic hepatitis B (CHB) patients.

METHODS AND RESULTS

The liver biopsy specimens of 30 patients with a clinical diagnosis of CHB were obtained before treatment and scored by Knodell's histological activity index. The specimens were then immunohistochemically stained with alpha-SMA and semiquantitatively evaluated. Fibrosis and the immunoreactivity of alpha-SMA in the periportal, perisinusoidal and pericentral areas were compared. Fibrosis and necroinflammatory activity in CHB patients were significantly correlated (P =0.022). Furthermore, the degree of alpha-SMA expression and the scores of fibrosis (in periportal, perisinusoidal and pericentral areas) were highly correlated (P =0.000, 0.001, 0.000, respectively).

CONCLUSIONS

In liver biopsy samples, alpha-SMA may prove to be a valuable marker in the evaluation of stellate cell activation and fibrosis progression and an early indicator of the development of fibrosis.

Intrahepatic gene expression profiles and alpha-smooth muscle actin patterns in hepatitis C virus induced fibrosis

To gain insight into pathogenic mechanisms underlying fibrosis in hepatitis C virus (HCV)-mediated liver injury, we compared intrahepatic gene expression profiles in HCV-infected patients at different stages of fibrosis and alpha-smooth muscle actin (alpha-SMA) staining patterns. We studied 21 liver biopsy specimens: 5 had no fibrosis (Ludwig-Batts stage 0); 10 had early portal or periportal fibrosis (stages 1 and 2); and 6, advanced fibrosis (stages 3 and 4). None of the patients had hepatocellular carcinoma. Transcriptional profiles were determined by high-density oligonucleotide microarrays. ANOVA identified 157 genes for which transcript abundance was associated with fibrosis stage. These defined three distinct hierarchical clusters of patients. Patients with predominantly stage 0 fibrosis had increased abundance of mRNAs linked to glycolipid metabolism. PDGF, a potent stellate cell mitogen, was also increased. Transcripts with increased abundance in stages 1 and 2 fibrosis were associated with oxidative stress, apoptosis, inflammation, proliferation, and matrix degradation, whereas transcripts increased in stages 3 and 4 were associated with fibrogenesis and cellular proliferation. Cells staining for alpha-SMA were detectable at all stages but infrequent in advanced fibrosis without active inflammation. A high frequency of such cells was associated with mRNAs linked to glycolipid metabolism. In conclusion, the presence of alpha-SMA-positive HSCs and expression of PDGF in stage 0 fibrosis suggests that stellate cells are activated early in HCV-mediated injury, possibly in response to oxidative stress resulting from inflammation and lipid metabolism. Increased abundance of transcripts linked to cellular proliferation in advanced fibrosis is consistent with a predisposition to cancer. Supplementary material for this article can be found on the HEPATOLOGY website (http://www.interscience.wiley.com/jpages/0270-9139/suppmat/index/html).

Nonresponders to hepatitis C virus antiviral therapy: pegylated interferons and beyond

Nonresponders to prior antiviral therapy are a heterogeneous but growing population of hepatitis C patients in the United States. The likelihood of response to retreatment with pegylated interferon(PEG IFN) and ribavirin (RBV) is largely dependent upon hepatitis C virus genotype and the type, duration, and response to prior antiviral therapy. Investigational trials with clinical and histological end points for nonresponders with advanced fibrosis including maintenance PEG IFN and other antifibrotic agents should be completed in the next 5 years. In the interim, decisions regarding retreatment with PEG IFN and RBV should be made on a case-by-case basis after considering the tolerability of prior treatment, the severity of underlying liver disease, and the anticipated likelihood of response.

Evaluation of liver fibrosis: a concise review

The diagnosis of liver fibrosis has traditionally relied on liver biopsy. However, recent studies have suggested that there can be up to a 33 % error in the diagnosis of cirrhosis. In this article, we review the current status of liver biopsy as a gold standard for the diagnosis of liver fibrosis and discuss the radiological and serum tests that have been proposed as potential adjuncts or alternatives to biopsies. Indirect markers of liver fibrosis which reflect alterations in liver function and or inflammation are discussed as well as more direct markers of liver fibrosis. The limitations of utilization of these markers for both cross-sectional diagnosis of fibrosis and monitoring disease progression or regression are discussed.

Effects of interferon treatment response on liver complications of chronic hepatitis C: 9-year follow-up study

OBJECTIVES

Fibrotic severity, biochemical indices of poor liver function, and sporadic transmission are independent predictors of liver complications among people with chronic hepatitis C. After accounting for these factors, we tested whether interferon treatment or the treatment response reduces the rate of liver cancer, liver-related death or transplantation, and other liver complications during extended follow-up.

METHODS

Liver clinic cohort of 455 patients with histologically proven chronic hepatitis C was followed prospectively for median 9 yr (IQ 6, 11 yr); 384 received interferon, 343 completed a treatment course. Liver complications were assessed in relation to treatment and treatment response in univariate and multivariate models, and survival to onset of liver-related complications was determined.

RESULTS

The annual incidence of total liver complications was 1.5% in treated and 2.9% in untreated patients and appeared quasilinear throughout 9-yr follow-up. Interferon treatment did not influence the rate of liver complications. However, the rate of complications increased exponentially with transition of the treatment response from sustained viral response (SVR), through response-relapse to nonresponse (or no treatment). By univariate analysis, response to interferon treatment was a significant predictor of complications. After adjustment for fibrosis score, serum albumin concentration and mode of transmission in a multivariate model, treatment response just failed to reach significance (p= 0.058) as a predictor of outcome.

CONCLUSIONS

Response to antiviral therapy, and particularly SVR, appears to reduce liver complications in chronic hepatitis C. However, in the absence of an antiviral treatment response, a course of interferon does not reduce risks of liver cancer or liver failure.

Hepatic stellate cells in hepatitis C patients: relationship with liver iron deposits and severity of liver disease

BACKGROUND AND AIM

To determine the relationship between hepatic stellate cell (HSC) populations and severity of liver disease and liver iron deposits in patients with chronic hepatitis C virus (HCV). We also studied the relationship between iron cellular distribution and HSC population and the role of HFE mutations in the determination of iron deposits.

METHODS

Forty-nine chronic HCV patients with varying degrees of liver damage and liver iron deposits were studied. A liver biopsy was scored for histology activity index (HAI), fibrosis and iron deposits. The number of HSC in the liver was evaluated by an immunohistochemical double-staining method to identify glial fibrillary acid protein (GFAP) and smooth muscle alpha-actin (alpha-SMA).

RESULTS

The HSC population was significantly higher in HCV patients than in normal controls and was predominant in zones 1 and 3. Liver iron deposits were observed in 49% of patients and were mild/moderate in most cases. We found a significantly higher number of GFAP and alpha-SMA positive cells in patients with liver iron deposits compared with those without iron deposits, and a positive correlation between liver iron scores and number (%) of GFAP and alpha-SMA positive cells. We observed a significantly higher number of GFAP and alpha-SMA positive cells in moderate/severe hepatitis than in minimal/mild hepatitis, and a positive correlation between GFAP and alpha-SMA positive cells and HAI and fibrosis scores.

CONCLUSIONS

Liver iron deposits in chronic HCV are common and are associated with activation of HSC. Thus, even mild iron deposits might stimulate HSC and contribute to liver damage.

Reversibility of hepatitis C virus-related cirrhosis

The aim of this retrospective study was to determine the potential reversibility of hepatitis C virus (HCV) cirrhosis with the combined antifibrotic effects of interferon-alpha and the increasing frequency of sustained virologic response. Sixty-four HCV-cirrhotic immunocompetent patients who underwent antiviral therapies (interferon-alpha with or without ribavirin) and pretreatment and posttreatment liver biopsies were included (group 1). Resolution of cirrhosis was defined as a decrease in the fibrosis score from 4 to 2 or less by the Metavir score after blinded analysis by 2 independent pathologists. An additional group of 4 HCV-infected dialysis patients (group 2) who had received antiviral treatment, among whom 3 underwent a combined renal and liver transplantation allowing the analysis of the whole liver, was also studied. In 5 (all stage Child A) of the 64 cirrhotic patients (7.8%), the final biopsy showed only F2 to portal and periportal fibrosis with rare fibrous septa without nodule formation. Four of these 5 were complete sustained responders (negative PCR and normal ALT), and 1 was a relapser. In group 2, reversibility of cirrhosis was observed in 3 of the 4 patients and was clearly shown in 2 patients by the analysis of the whole-liver examination at the time of the hepatectomy preceding the transplantation. In conclusion, long-lasting suppression of the necroinflammatory activity of liver disease and/or antifibrogenetic effects of interferon-alpha may allow regression of cirrhosis.

Approaches for treatment of liver fibrosis in chronic hepatitis C

In the past 20 years, the elucidation of the mechanisms responsible for liver fibrogenesis has provided many potential targets for antifibrotic treatments. Difficulty has arisen, however, from the fact that fibrogenesis is part of a general beneficial wound healing process. To be successful, an antifibrotic treatment of HCV might need to be delivered selectively to the hepatic site of fibrogenesis or targeted precisely at an HCV-specific regulatory mechanism. It is likely that in the future, besides viral eradication, another treatment goal in chronic HCV infection will be to reverse existing fibrosis, but considerable work is necessary before making this a reality.

Changes in serum and histology of patients with chronic hepatitis B after interferon alpha-2b treatment

AIM: Chronic hepatitis B is a serious health problem. Interferon has long been used to treat Chronic hepatitis B. To evaluate the effects of interferon on chronic hepatitis B better, we designed the study to investigate the changes in sera and liver histology of patients with chronic hepatitis B after interferon alpha-2b treatment.

METHODS: Twenty-four patients with chronic hepatitis B were enrolled in this study. They all received interferon alpha-2b treatment as following: 3 million units, i.m. t.i.w., for 18 weeks. Sera of all patients were obtained respectively for evaluation of ALT, HBsAg, HBcAg, HBeAg, HBV DNA and TIMP-1 before and after interferon treatment, also a liver biopsy pre- and post-treatment was performed for comparison of HAI, HBsAg, HBcAg, HBeAg, TIMP-1 and activated HSC in the liver tissue.

RESULTS: Patients who had normalization of serum ALT and seroconversion of HBeAg and/or HBV DNA (blot hybridization) after treatment were defined as responders. The response rate in this study group was 37.5% (7/24). Compared to pretreatment, the serum HBV DNA and TIMP-1 decreased significantly (P < 0.05), so did the HAI, HBcAg, HBeAg, TIMP-1 and activated HSC (P < 0.05).

CONCLUSION: The significant decrease in HBV DNA in sera, the seroconversion of HBeAg, and the decrease of viral expression in liver indicated that interferon alpha-2b treatment can inhibit viral replication. The normalization of ALT in sera and the improvement of HAI in liver showed that interferon alpha-2b can improve the liver histology of patients with chronic hepatitis B. At the same time, interferon alpha-2b treatment can reduce the TIMP-1 in serum and liver and decrease the number of activated HSC, which may allievate or inhibit hepatic fibrosis. Although the response rate was unsatisfactory, interferon play a benefical role on patients with chronic hepatitis B in other respects. We still need further studies to improve the therapy effects.

Fibrosis and disease progression in hepatitis C

The progression of fibrosis in chronic hepatitis C determines the ultimate prognosis and thus the need and urgency of therapy. Fibrogenesis is a complex dynamic process, which is mediated by necroinflammation and activation of stellate cells. The liver biopsy remains the gold standard to assess fibrosis. Scoring systems allow a semiquantitative assessment and are useful for cross-sectional and cohort studies and in treatment trials. The rate at which fibrosis progresses varies markedly between patients. The major factors known to be associated with fibrosis progression are older age at infection, male gender, and excessive alcohol consumption. Viral load and genotype do not seem to influence significantly the progression rate. Progression of fibrosis is more rapid in immunocompromised patients. Hepatic steatosis, obesity, and diabetes may also contribute to more rapid progression of fibrosis. There are no tests that reliably predict the rate of progression of fibrosis in an individual patient. High serum alanine aminotransferase (ALT) levels are associated with a higher risk of fibrosis progression, and worsening of fibrosis is uncommon in patients with persistently normal serum aminotransferase levels. Serum markers for fibrosis are not reliable and need to be improved and validated. Liver biopsy provides the most accurate information on the stage of fibrosis and grade of necroinflammation, both of which have prognostic significance. Repeating the liver biopsy, 3 to 5 years after an initial biopsy is the most accurate means of assessing the progression of fibrosis.

Fibrosis and disease progression in hepatitis C

The progression of fibrosis in chronic hepatitis C determines the ultimate prognosis and thus the need and urgency of therapy. Fibrogenesis is a complex dynamic process, which is mediated by necroinflammation and activation of stellate cells. The liver biopsy remains the gold standard to assess fibrosis. Scoring systems allow a semiquantitative assessment and are useful for cross-sectional and cohort studies and in treatment trials. The rate at which fibrosis progresses varies markedly between patients. The major factors known to be associated with fibrosis progression are older age at infection, male gender, and excessive alcohol consumption. Viral load and genotype do not seem to influence significantly the progression rate. Progression of fibrosis is more rapid in immunocompromised patients. Hepatic steatosis, obesity, and diabetes may also contribute to more rapid progression of fibrosis. There are no tests that reliably predict the rate of progression of fibrosis in an individual patient. High serum alanine aminotransferase (ALT) levels are associated with a higher risk of fibrosis progression, and worsening of fibrosis is uncommon in patients with persistently normal serum aminotransferase levels. Serum markers for fibrosis are not reliable and need to be improved and validated. Liver biopsy provides the most accurate information on the stage of fibrosis and grade of necroinflammation, both of which have prognostic significance. Repeating the liver biopsy, 3 to 5 years after an initial biopsy is the most accurate means of assessing the progression of fibrosis.

Intrahepatic expression of the hepatic stellate cell marker fibroblast activation protein correlates with the degree of fibrosis in hepatitis C virus infection

BACKGROUND

Activated hepatic stellate cells (HSCs), recognised by their alpha smooth muscle actin immunoreactivity, are primarily responsible for liver fibrosis. However, the presence of alpha smooth muscle actin positive HSCs is not always associated with the development of liver fibrosis. Recently, other markers of human HSCs including the gelatinase fibroblast activation protein (FAP) and glial fibrillary acidic protein have been identified.

AIMS

We examined the relationship between the expression of these HSC markers and the severity of liver injury in patients with chronic hepatitis C virus infection.

METHODS

Liver tissue from 27 patients was examined using immunohistochemistry. Linear correlation analysis was used to compare staining scores with the stage and grade of liver injury.

RESULTS-CONCLUSIONS

FAP expression, seen at the tissue-remodelling interface, was strongly and significantly correlated with the severity of liver fibrosis. A weaker correlation was seen between glial fibrillary acidic protein expression and fibrosis stage. This contrasted with the absence of a relationship between alpha smooth muscle actin and the fibrotic score. A correlation was also observed between FAP expression and necroinflammatory score. In summary, FAP expression identifies a HSC subpopulation at the tissue-remodelling interface that is related to the severity of liver fibrosis.

Decreasing fibrogenesis: an immunohistochemical study of paired liver biopsies following lamivudine therapy for chronic hepatitis B

BACKGROUND

Activation of hepatic stellate cells is the earliest step in fibrogenesis. Alpha-smooth muscle actin (alpha-SMA), expressed by activated hepatic stellate cells, and C-terminal procollagen alpha1(III) propeptide (PIIICP) are early markers of fibrogenesis and should precede fibrosis.

AIM

Determine if suppression of hepatitis B virus replication with lamivudine would decrease fibrogenesis as measured by immunohistochemical markers.

METHODS

Paired liver biopsies from patients with hepatitis B before and after therapy with lamivudine (n=47) or placebo (n=33) were studied. alpha-SMA and PIIICP were detected in paraffin-embedded tissue by immunohistochemistry and quantified in a blinded manner by video imaging analysis.

RESULTS

Liver biopsies from patients treated with lamivudine showed a significant decrease in alpha-SMA expression (1.06+/-0.23 vs. 0.58+/-0.11, pre vs. post, P<0.05). Placebo recipients had increased levels of alpha-SMA (0.82+/-0.14 vs. 1.32+/-0.21, P<0.05). PIIICP was similarly decreased after lamivudine. Among subjects whose Histologic Activity Index fibrosis score was unchanged or worsened, the mean change in alpha-SMA expression was significantly decreased in the lamivudine group compared with placebo.

CONCLUSIONS

Lamivudine decreased markers of hepatic stellate cell activation and collagen synthesis. Immunohistochemical techniques are sensitive for assessing fibrogenesis and will be useful in trials of antiviral and antifibrotic agents.

Increased oxidative stress in dimethylnitrosamine-induced liver fibrosis in the rat: effect of N-acetylcysteine and interferon-alpha

Oxidative stress may represent a common link between chronic liver damage and hepatic fibrosis. Antioxidants and interferon seem to protect against hepatic stellate cell (HSC) activation and liver fibrosis. This study evaluated (1) the effect of the profibrotic agent dimethylnitrosamine (DMN) on the hepatic oxidative balance in the rat; (2) the role played by the antioxidant agent N-acetylcysteine (NAC); and (3) the antifibrotic effects of two different types of interferon-alpha: recombinant alpha-2b (rIFN-alpha) and leukocyte alpha (LeIFN-alpha). Five groups of rats received: (1) saline; (2) DMN; (3) DMN + NAC; (4) DMN + rIFN-alpha; and (5) DMN + LeIFN-alpha. Oxidative balance was evaluated by hepatic glutathione, TBARs, protein carbonyl, and sulfhydryl determination. Fibrosis was determined by hepatic hydroxyproline content and fibronectin (FN) staining (immunohistochemistry). DMN rats showed a diffuse FN deposition, an impaired oxidative balance, and higher hepatic hydroxyproline levels compared to that of controls. NAC administration significantly reduced FN deposition, increased hepatic glutathione, and decreased TBARs and protein carbonyls. Administration of IFN-alpha exerted different effects according to the type used. Both IFNs decreased FN deposition; however, LeIFN-alpha significantly improved histology and oxidative parameters compared to those of untreated DMN and rats treated with rIFN-alpha. This study shows the role of free radicals in this model of hepatic fibrosis; the protective effect of NAC against liver fibrosis; and the antifibrotic effect exerted by IFN-alpha (particularly LeIFN-alpha) independent of its antiviral activity.

Effect of interferon-alpha on experimental septal fibrosis of the liver - study with a new model

Interferon-alpha is used in antiviral therapy in humans, mainly for viral hepatitis B and C. An anti-fibrotic effect of interferon has been postulated even in the absence of anti-viral response, which suggests that interferon directly inhibits fibrogenesis. Rats infected with the helminth Capillaria hepatica regularly develop diffuse septal fibrosis of the liver, which terminates in cirrhosis 40 days after inoculation. The aim of this study was to test the anti-fibrotic effect of interferon in this experimental model. Evaluation of fibrosis was made by three separate methods: semi-quantitative histology, computerized morphometry and hydroxyproline measurements. Treatment with interferon-alpha proved to inhibit the development of fibrosis in this model, especially when doses of 500,000 and 800,000 IU were used for 60 days. Besides confirming the anti-fibrotic potential of interferon-alpha on a non-viral new experimental model of hepatic fibrosis, a clear-cut dose-dependent effect was observed.

Adult-onset herpes simplex virus hepatitis with diffuse myofibroblastic transformation of hepatic stellate cells (Ito cells) in non-necrotic areas

The myofibroblastic transformation of hepatic stellate cells (HSC; also known as Ito cells) usually occurs following necrosis of adjacent liver cells. No report has previously found that such a transformation occurs in herpes simplex virus (HSV) hepatitis. We present an autopsy case of HSV hepatitis with myofibroblastic transformation of HSC that is different from the usual transformation of HSC. The patient was a 66-year-old woman who had received various therapies for cutaneous T-cell lymphoma. An autopsy revealed submassive hepatic necrosis with hemorrhage due to HSV hepatitis. HSV infection was confirmed by DNA in situ hybridization in liver tissue. Immunohistochemical staining for alpha-smooth muscle actin (ASMA) showed a strong positive reaction in almost all of the HSC in non-necrotic areas. However, in necrotic areas, the HSC were completely negative for ASMA. These findings indicate that not only liver cells but also HSC can become necrotic in HSV hepatitis. In contrast, in non-necrotic areas, almost all of the HSC showed active transformation to myofibroblasts.

Steatosis and chronic hepatitis C: analysis of fibrosis and stellate cell activation

BACKGROUND/AIMS

Steatosis is a frequent histological finding in chronic hepatitis C and is associated with increased hepatic fibrosis.

METHODS

We studied 80 patients with untreated chronic hepatitis C to determine whether steatosis contributes to fibrosis through a steatohepatitis-like pathway.

RESULTS

Fine sinusoidal and/or central vein fibrosis was present in 52 patients (65%). This was typically located in acinar zone 3 and had a chicken-wire appearance similar to that seen in steatohepatitis. A statistically significant relationship was found between subsinusoidal fibrosis and age (r(s) = 0.33, P = 0.003) and grade of steatosis (r(s) = 0.35, P = 0.001). Mean body mass index was higher in patients with focal (28.4 +/- 4.7 kg/m2) or extensive (29.6 +/- 5.9 kg/m2) subsinusoidal fibrosis than in those patients with no subsinusoidal fibrosis (25.5 +/- 3.7 kg/m2). The extent of alpha-smooth muscle actin staining (as a marker of stellate cell activation) correlated with the degree of portal inflammation and the stage of portal fibrosis, but not with the grade of hepatic steatosis.

CONCLUSIONS

These findings suggest that in hepatitis C infection, host factors, particularly adiposity, contribute to both steatosis and acinar fibrosis. The implication of these observations is that weight reduction may provide an important therapeutic strategy for patients with chronic hepatitis C.

In situ expression of transforming growth factor-beta1-3, latent transforming growth factor-beta binding protein and tumor necrosis factor-alpha in liver tissue from patients with chronic hepatitis C

BACKGROUND

The mechanisms determining liver damage in chronic hepatitis C remain unclear. The aim was to evaluate the in situ expression of transforming growth factor beta (TGF-beta) and tumor necrosis factor-alpha (TNF-alpha), two key cytokines implicated as important pathogenic mediators in the development of liver fibrosis.

METHODS

In situ expression of TNF-alpha and of TGF-beta isoforms 1-3, and its transport protein latent TGF-beta binding protein (LTBP), was determined by immunohistochemistry in 9 untreated patients with chronic hepatitis C infection and in 6 controls without liver disease. In addition, TGF-beta1 expression was analyzed in 10 HCV patients before and after treatment with interferon-alpha alone, or in combination with ribavirin.

RESULTS

Liver biopsies from HCV patients showed positive staining for TGF-beta1-3 isoforms and LTBP, and to a lesser degree for TNF-alpha, in areas with inflammation and fibrosis. Normal control liver showed no positive staining. TGF-beta1 expression before treatment, quantified by morphometric analysis, did not differ between non-responders and sustained responders. In patients responding to therapy, TGF-beta1 expression decreased in parallel with histological improvement, while no difference in TGF-beta1 expression was seen before and after treatment in non-responders.

CONCLUSION

These results suggest that TNF-alpha and all three isoforms of TGF-beta are involved in the pathogenesis of HCV related liver disease, and that treatment leading to eradication of the virus affects the expression of TGF-beta1.

Decorin and actin expression and distribution in patients with chronic hepatitis C following interferon-alfa-2b treatment

BACKGROUND/AIMS

Chronic hepatitis C can lead to cirrhosis and hepatocellular carcinoma. Interferon-alfa therapy may prevent the progression of the disease. The expressions of decorin and alfa-smooth muscle cell actin of the extracellular matrix play a central role in liver fibrosis. We set out to assess the expressions of these proteins in chronic hepatitis C patients, and to evaluate how they can be modified by interferon-alfa therapy.

METHODS

Twenty chronic hepatitis C patients received interferon-alfa-2b therapy for 6 months (group I) or 12 months (group II). Liver biopsy samples were taken before and after the therapy. The alfa-smooth muscle actin-positive cells were determined with a monoclonal antibody, and decorin expression was detected with a polyclonal antibody. The cells were evaluated with a semiquantitative scoring method. For statistical analysis, non-parametric methods were used.

RESULTS

Before the therapy, alfa-smooth muscle actin-labeled cells and marked decorin expression were present throughout all the acinar zones. Interferon-alfa-2b therapy resulted in significant decreases in both the number of alfa-smooth muscle actin-positive cells and the decorin expression. The alfa-smooth muscle actin-positive cells and decorin expression correlated with the histological activity index (R=0.72, p<0.03, R=0.68, p<0.05).

CONCLUSIONS

This study demonstrates that a large number of alfa-smooth muscle actin-positive cells and a marked decorin expression are frequent findings in chronic hepatitis C. Treatment with interferon-alfa-2b for 12 months reduced the number of labeled cells and the decorin expression. The results suggest that interferon-alfa-2b is capable of interfering with fibrogenesis in an early and presumably still reversible phase of chronic hepatitis C.

Changes in serum tissue inhibitor of matrix metalloproteinase-1 after interferon alpha treatment in chronic hepatitis C

BACKGROUND/AIMS

The aim of this study was to evaluate the effect of interferon alpha on the metabolism of hepatic fibrosis in chronic hepatitis C, monitoring serum tissue inhibitor of matrix metalloproteinase-1(TIMP-1) and N-terminal propeptide of type III procollagen (PIIINP) reflecting fibrolysis and fibrogenesis, respectively.

METHODS

Serum levels of TIMP-1 and PIIINP were serially measured in 112 treated and 31 untreated patients with chronic hepatitis C during and after interferon alpha treatment. Furthermore, the relationships between these serum markers and the grades of hepatic fibrosis after interferon therapy were also investigated.

RESULTS

Serum pretreatment levels of TIMP-1 and PIIINP in non-responders were significantly higher than those in sustained and transient responders, but these levels were not different in the latter two groups. Serum TIMP-1 levels decreased significantly during and after treatment in sustained responders, and decreased temporarily at the end of treatment in transient responders, although these levels were unchanged during and after treatment in non-responders and untreated patients. In contrast, serum PIIINP levels decreased significantly during and after treatment in all treated groups, but were unchanged in untreated patients. Histological examination 12 months after interferon was completed demonstrated that hepatic fibrosis improved in sustained responders and was unchanged in transient and non-responders, but progressed in untreated patients.

CONCLUSION

These results suggest that interferon alpha treatment of chronic hepatitis C may improve hepatic fibrosis in sustained responders by the acceleration of fibrolysis as well as the inhibition of fibrogenesis, and that it may suppress the progression of hepatic fibrosis in non-sustained responders by the inhibition of fibrogenesis.

A randomized, controlled trial of maintenance interferon therapy for patients with chronic hepatitis C virus and persistent viremia

BACKGROUND & AIMS

: At least half of patients with chronic hepatitis C virus (HCV) fail to respond to interferon or interferon/ribavirin therapy. Histological improvement is observed in some nonresponders. We conducted a randomized, controlled trial to determine if maintenance interferon therapy could prevent histological progression in this subset of nonresponders.

METHODS

Fifty-three patients with chronic HCV were enrolled. All were HCV-RNA positive after 6 months of treatment with interferon alfa-2b but had a histological response. Twenty-seven of the patients were randomly assigned to continue interferon (3 MU 3 times weekly) for 24 months; 26 patients discontinued treatment and were observed prospectively. Alanine aminotransferase (ALT) level and HCV-RNA titer were monitored, and liver biopsy was repeated every 12 months.

RESULTS

Before interferon therapy, the 2 groups were well matched for all demographic factors, serum ALT (94.0 +/- 15.6), log HCV-RNA titer (5. 85 +/- 0.15 copies/mL), histology score (9.5 +/- 0.2), and percentage with cirrhosis (25%). After 6 months of treatment, significant reductions (P < 0.05) in serum ALT level (62.6 +/- 9.6), log HCV-RNA titer (4.79 +/- 0.13 copies/mL), and hepatic inflammation (4.0 +/- 0.2) were observed. These improvements were maintained in the patients randomized to continue interferon. Stopping treatment was associated with an increase in serum ALT, log HCV-RNA, and hepatic inflammation back to baseline. After 30 months of treatment, mean fibrosis score declined from 2.5 to 1.7 and 80% of patients had histological improvement (P < 0.03). Discontinuation of interferon was associated with an increase in mean fibrosis score from 2.2 to 2.4 and worsening of hepatic histology in 30% of patients (P < 0.01).

CONCLUSIONS

These data support the hypothesis that maintenance interferon may prevent histological progression of chronic HCV in patients who remain viremic.

Myofibroblasts. I. Paracrine cells important in health and disease

Myofibroblasts are a unique group of smooth-muscle-like fibroblasts that have a similar appearance and function regardless of their tissue of residence. Through the secretion of inflammatory and anti-inflammatory cytokines, chemokines, growth factors, both lipid and gaseous inflammatory mediators, as well as extracellular matrix proteins and proteases, they play an important role in organogenesis and oncogenesis, inflammation, repair, and fibrosis in most organs and tissues. Platelet-derived growth factor (PDGF) and stem cell factor are two secreted proteins responsible for differentiating myofibroblasts from embryological stem cells. These and other growth factors cause proliferation of myofibroblasts, and myofibroblast secretion of extracellular matrix (ECM) molecules and various cytokines and growth factors causes mobility, proliferation, and differentiation of epithelial or parenchymal cells. Repeated cycles of injury and repair lead to organ or tissue fibrosis through secretion of ECM by the myofibroblasts. Transforming growth factor-beta and the PDGF family of growth factors are the key factors in the fibrotic response. Because of their ubiquitous presence in all tissues, myofibroblasts play important roles in various organ diseases and perhaps in multisystem diseases as well.

Hepatic stellate cell activation and liver fibrosis are associated with necroinflammatory injury and Th1-like response in chronic hepatitis C

BACKGROUND/AIMS

The involvement of a direct viral cytopathic effect or an immune-mediated mechanism in the progression of hepatic damage in chronic hepatitis C is controversial. The type of immune response is itself a matter of controversy, and histological data are lacking. The aim of this study was to identify the factors associated with the progression of liver injury in 30 HCV/RNA-positive untreated patients with chronic hepatitis.

METHODS

Necroinflammatory and architectural damage were evaluated using Ishak's score. Activated hepatic stellate cells (HSC) were visualized by immunohistochemistry for alpha-smooth muscle actin (alphaSMA) and quantitated by morphometry. Plasma HCV/RNA was evaluated using a competitive RT-PCR method. To study the type of immune response involved in the progression of liver injury, interferon gamma (IFNgamma)-positive cells (as expression of a Th1-like response) were evaluated by immunohistochemistry and quantitated by morphometry.

RESULTS

HSC were mostly detected close to areas of lobular necroinflammation or lining fibrotic septa. The alphaSMA- and Sirius Red-positive parenchyma correlated significantly with necroinflammatory and architectural scores. IFNgamma-positive cells were detected in periportal areas associated with the inflammatory infiltrates and significantly correlated with architectural damage. No relationship was found between the histological features of liver injury and viral load.

CONCLUSIONS

HSC activation and progression of liver injury are unrelated to viral load but associated with a Th1-like response, a plausible target for the treatment of chronic hepatitis C.

Quantitative analysis of liver fibrosis and stellate cell changes in patients with chronic hepatitis C after interferon therapy

OBJECTIVE

The proliferation and differentiation of stellate (Ito, or fat-storing) cells into myofibroblast-like cells is responsible for the development of liver fibrosis. Using computer image analysis, we evaluated the changes of alpha smooth muscle actin-positive stellate cells and liver fibrosis after interferon-alpha or -beta (IFN-alpha, beta) therapy in patients with chronic hepatitis C.

METHODS

Patients with chronic hepatitis C were treated with IFN-alpha or -beta and were divided into three groups on the basis of clinical criteria; a complete responder group (CR, 18 of 51), a partial responder group (PR, 17 to 51), and a nonresponder group (NR, 16 of 51). Liver fibrosis was assessed from specimens stained with Sirius red and was quantitated by computer image analysis. We also evaluated alpha-smooth muscle actin expression in the liver before and after IFN therapy by a semiquantitative scoring method (the alpha-smooth muscle actin index).

RESULTS

Before IFN therapy, a large number of stellate cells expressing a-smooth muscle actin were present in the liver biopsy specimens. There was a significant correlation (r = 0.699, p < 0.05) between the change in the percent area of fibrosis and the alpha-smooth muscle actin index before and after IFN therapy in all groups. The complete responder group also showed a significant reduction of a-smooth muscle actin-expressing cells that was correlated with the reduction of serum ALT (r = 0.686, p < 0.05).

CONCLUSION

These results suggest a-smooth muscle actin-expressing cells are responsible for liver fibrosis, and the elimination of factors stimulating matrix synthesis (e.g., hepatitis virus) may decrease liver fibrosis.

Chronic hepatitis C in children: the pathological and clinical spectrum

BACKGROUND & AIMS

Apart from the high-risk groups, the pathology of chronic hepatitis C in children is not well known. The aim of this study was to investigate the morphology of chronic hepatitis C in children without any underlying systemic disease and to evaluate its relationship to clinicovirological factors.

METHODS

Liver biopsy specimens from 80 children positive for antibody to hepatitis C virus were evaluated using a semiquantitative scoring system.

RESULTS

Chronic hepatitis was mild in most cases but had high-grade activity in 17 children (21.2%). A significant association was found between the grade of focal necrosis and alanine transaminase levels (P < 0.003). Fibrosis was absent in 22 cases (27.5%), mild in 44 (55%), and moderate in 13 (16.2%). Only 1 patient had cirrhosis. A significant relationship was detected between fibrosis scores and (1) duration of disease (P < 0.03); (2) portal inflammation (P < 0. 002); and (3) interface hepatitis (P < 0.003).

CONCLUSIONS

In otherwise healthy children, chronic hepatitis C is a morphologically mild disease in most cases. Fibrosis increases with the duration of disease, suggesting that end-stage disease may develop in young adulthood. Alanine transaminase levels correlate with intralobular focal necrosis but not with other lesions. In this respect, liver biopsy retains its importance in the management of chronic hepatitis C in children.

Effects of long-term administration of interferon alpha in two models of liver fibrosis in rats

BACKGROUND/AIMS

The aim of this study was to assess the effect of the early and chronic administration of interferon alpha in the prevention of hepatic fibrosis and portal hypertension.

METHODS

Rats with liver fibrosis due to bile duct ligation or CCl4 were divided into three groups: sham, placebo and interferon alpha2a 100,000 UI/day. Liver fibrosis was assessed by the area of fibrosis (image analysis), liver hydroxyproline and mRNA (fibronectin, procollagen alpha2(I)) contents, and serum hyaluronate. Systemic and splanchnic hemodynamics were also evaluated.

RESULTS

Interferon alpha significantly decreased fibrosis in the CCl4 model only: area of fibrosis: 13.9+/-3.7 vs 10.5+/-3.3% (p<0.05), hydroxyproline: 1.8+/-0.6 vs 1.2+/-0.2 mg/g wet liver (p<0.001), respectively placebo vs interferon alpha. There was a significant correlation between the area of fibrosis and hydroxyproline liver content (r=0.77 in the biliary model and r=0.87 in the CCl4 model, p<0.0001). Interferon decreased spleno-renal shunt blood flow (2.0+/-1.8 vs 0.9+/-0.7 ml/min; p<0.05) but not portal pressure in the CCl4 model. No significant effects were observed in rats with biliary fibrosis.

CONCLUSIONS

The early and chronic administration of interferon alpha prevents the development of liver fibrosis and porto-collateral circulation in the CCl4 model but not in the biliary model. However, the antifibrotic effects of interferon need to be confirmed in further studies.

Influence of pretreatment lesions on histologic response to interferon therapy in chronic hepatitis C

We have assessed the predictive value of the grade of pretreatment liver lesions on histologic response to interferon therapy in patients with chronic hepatitis C. In 93 patients with chronic hepatitis C virus (HCV) infection who showed an initial response to interferon therapy, HCV RNA load and serum aminotransferase levels together with grade of liver histologic lesions were assessed at baseline and 6 months after treatment cessation. Regression of portal and periportal necroinflammation was observed only in sustained responders (normalization of aminotransferase levels and HCV RNA clearance). Neither short-term response nor the absence of virus was associated with significant histologic changes in the liver biopsies. Logistic regression analysis showed that pretreatment histologic lesion was an independent predictive factor of biologic response in the histologic regression of lesions 6 months after cessation of interferon treatment. In conclusion, a dense inflammatory necrotic activity is a positive predictor of histologic response in interferon-treated patients with HCV.

Pharmacological aspects of pentoxifylline with emphasis on its inhibitory actions on hepatic fibrogenesis

1. Pentoxifylline (PTX), a derivative of the methylxanthine theobromine, has been used for many years in the treatment of peripheral vascular diseases. Increased red blood cell flexibility, reduction of blood viscosity, and decreased potential of platelet aggregation are the basic actions of PTX, resulting in therapeutic benefits due to improved microcirculation and tissue oxygenation. 2. PTX's generally accepted mechanism of action is the inhibition of phosphodiesterases, leading to increased intracellular levels of cyclic adenosine monophosphate (cAMP). 3. A number of studies have shown PTX's effects on the cytokine network. The most relevant clinical results are the therapeutic benefits of PTX in attenuating the effects of tumor necrosis factor-alpha (TNF-alpha) in conditions such as septic shock. 4. PTX also has been found to exert antifibrogenic actions, using cultured fibroblasts or animal models of fibrosis, including liver fibrosis. 5. In hepatic stellate cell culture PTX has been shown to inhibit the basic reactions of liver fibrogenesis, being effective on cytokines and growth factors relevant in fibrogenesis of the liver, too. 6. Therefore, PTX might be an effective drug with few side effects in the treatment of liver fibrosis. Further clinical studies have to be done to establish the real therapeutic benefits of PTX in liver fibrosis and cirrhosis.

Hepatic stellate cell activation in genetic haemochromatosis. Lobular distribution, effect of increasing hepatic iron and response to phlebotomy

BACKGROUND/AIMS

Activated hepatic stellate cells produce increased levels of collagen in animal models of chronic iron overload; however, their role in human genetic haemochromatosis is unknown. This study examined the relationship between hepatic iron concentration and hepatic stellate cell activation in genetic haemochromatosis.

METHODS

Liver biopsies from 75 patients (55 with haemochromatosis, 14 haemochromatosis patients both pre- and post-phlebotomy and six non iron-loaded disease control subjects) were stained for iron using Perls' Prussian Blue. Thirty biopsies in which there was no evidence of either steatosis or inflammation were subjected to immunohistochemistry for alpha-smooth muscle actin and desmin and counterstained for iron. Forty-five biopsies demonstrated either steatosis or inflammation, in addition to excess iron.

RESULTS

Stellate cells were identified by light microscopy as perisinusoidal cells containing numerous intracellular fat droplets. alpha-Smooth muscle actin was detected in biopsies with an hepatic iron concentration >60 micromol/g dry weight. Increasing hepatic iron concentration and hepatic iron index correlated with an increase in alpha-smooth muscle actin expression (r=0.81 and 0.72, respectively). Phlebotomy resulted in a significant decrease in alpha-smooth muscle actin expression. In early disease prior to histological evidence of collagen deposition, whilst activated stellate cells were located in Zone 1, greater numbers were found in Zones 2 and 3 distal to the region of heaviest iron overload.

CONCLUSIONS

This study has demonstrated for the first time in humans a correlation between hepatic iron concentration and stellate cell activation in haemochromatosis, which is reversed by iron removal. Humoral factors from either iron-loaded hepatocytes or activated Kupffer cells may be responsible for early stellate cell activation in areas of the liver remote from heavy iron loading.