Expression of Fc Fragment Receptors of Immunoglobulin G (FcγRs) in Rat Hepatic Stellate Cells

Agalactosyl IgG induces liver fibrogenesis via Fc gamma receptor 3a on human hepatic stellate cells

The relevance of aberrant serum IgG N-glycosylation in liver fibrosis has been identified; however, its causal effect remains unclear. Because hepatic stellate cells (HSCs) contribute substantially to liver fibrosis, we investigated whether and through which mechanisms IgG N-glycosylation affects the fibrogenic properties of HSCs. Analysis of serum IgG1 N-glycome from 151 patients with chronic hepatitis B or liver cirrhosis revealed a positive correlation between Ishak fibrosis grading and IgG1 with agalactosyl N-glycoforms on the crystallizable fragment (Fc). Fc gamma receptor (FcγR) IIIa was observed in cultured human HSCs and HSCs in human liver tissues, and levels of FcγRIIIa in HSCs correlated with the severity of liver fibrosis. Additionally, agalactosyl IgG treatment caused HSCs to have a fibroblast-like morphology, enhanced migration and invasion capabilities, and enhanced expression of the FcγRIIIa downstream tyrosine-protein kinase SYK. Furthermore, agalactosyl IgG treatment increased fibrogenic factors in HSCs, including transforming growth factor (TGF)-β1, total collagen, platelet-derived growth factor subunit B and its receptors, pro-collagen I-α1, α-smooth muscle actin, and matrix metalloproteinase 9. These effects were more pronounced in HSCs that stably expressed FCGR3A and were reduced in FCGR3A knockout cells. Agalactosyl IgG and TGF-β1 each increased FCGR3A in HSCs. Furthermore, serum TGF-β1 concentrations in patients were positively correlated with agalactosyl IgG1 levels and liver fibrosis severity, indicating a positive feedback loop involving agalactosyl IgG, HSC-FcγRIIIa, and TGF-β1. In conclusion, agalactosyl IgG promotes fibrogenic characteristics in HSCs through FcγRIIIa. © 2024 The Pathological Society of Great Britain and Ireland.

Pyruvate Oxidation Sustains B Cell Antigen-Specific Activation to Exacerbate MASH

B cells play a crucial role in the pathogenesis of metabolic dysfunction-associated steatohepatitis (MASH), a severe form of steatotic liver disease that if persistent can lead to cirrhosis, liver failure, and cancer. Chronic inflammation and fibrosis are key features of MASH that determine disease progression and outcomes. Recent advances have revealed that pathogenic B cell-derived cytokines and antibodies promote the development of MASH. However, the mechanisms through which B cells promote fibrosis and the metabolic adaptations underlying their pathogenic responses remain unclear. Here, we report that a subset of mature B cells with heightened cytokine responses accumulate in the liver and promote inflammation in MASH. To meet the increased energetic demand of effector responses, B cells increase their ATP production via oxidative phosphorylation (OXPHOS) fueled by pyruvate oxidation in a B cell receptor (BCR)-specific manner. Blocking pyruvate oxidation completely abrogated the inflammatory capacity of MASH B cells. Accordingly, the restriction of the BCR led to MASH attenuation, including reductions in steatosis, hepatic inflammation, and fibrosis. Mechanistically, BCR restriction decreased B cell maturation, activation, and effector responses in the liver, accompanied by decreased T cell- and macrophage-mediated inflammation. Notably, attenuated liver fibrosis in BCR-restricted mice was associated with lower IgG production and decreased expression of Fc-gamma receptors on hepatic stellate cells. Together, these findings indicate a key role for B cell antigen-specific responses in promoting steatosis, inflammation, and fibrosis during MASH.

The association of serum immunoglobulin and complement levels and liver fibrosis and inflammation stage in patients with chronic hepatitis B

The utility of measurement of serum immunoglobulin and complement in chronic hepatitis B (CHB) patients remains controversial. This study aimed to investigate the association of serum immunoglobulin and complement levels and liver fibrosis and inflammation stage in CHB patients. A total of 687 patients with CHB who underwent liver biopsy were enrolled. Serum immunoglobulin and complement were measured before liver biopsy, and liver pathological results were recorded. Associations of serum immunoglobulin and complement levels and liver fibrosis and inflammation stage were analysed. C3, C4, IgG and IgG1 had statistically significant differences among different fibrosis and different inflammation groups. Both C3 and C4 negatively correlated with fibrosis and inflammation stage, but IgG and IgG1 showed opposite results. C3, C4, IgG and IgG1 had statistical significance to predict ≥S2, ≥S3 and S4, and also had statistical significance to predict ≥G2, ≥G3 and G4. The area under curve (AUC) of the combination of C3, C4 and IgG (C3 + C4 + IgG) for predicting ≥S2, ≥S3 and S4 was 0.640 (95% CI: 0.603, 0.676), 0.674 (95% CI: 0.638, 0.709) and 0.744 (95% CI: 0.710, 0.776), respectively. The AUC of C3 + C4 + IgG for predicting ≥G2, ≥G3 and G4 was 0.723 (95% CI: 0.688, 0.756), 0.674 (95% CI: 0.638, 0.709) and 0.771 (95% CI: 0.738, 0.802), respectively. C3, C4, IgG and IgG1 are correlated with liver fibrosis and inflammation stage in CHB patients. C3, C4, IgG and IgG1 have diagnostic value for liver fibrosis and inflammation. C3 + C4 + IgG may improve diagnostic accuracy.

A Comprehensive Review on Liver Targeting: Emphasis on Nanotechnology- based Molecular Targets and Receptors Mediated Approaches

BACKGROUND

The pathogenesis of hepatic diseases involves several cells, which complicates the delivery of pharmaceutical agents. Many severe liver diseases affecting the worldwide population cannot be effectively treated. Major hindrances or challenges are natural physiological barriers and non-specific targeting of drugs administered, leading to inefficient treatment. Hence, there is an earnest need to look for novel therapeutic strategies to overcome these hindrances. A kind of literature has reported that drug safety and efficacy are incredibly raised when a drug is incorporated inside or attached to a polymeric material of either hydrophilic or lipophilic nature. This has driven the dynamic investigation for developing novel biodegradable materials, drug delivery carriers, target-specific drug delivery systems, and many other novel approaches.

OBJECTIVE

Present review is devoted to summarizing receptor-based liver cell targeting using different modified novel synthetic drug delivery carriers. It also highlights recent progress in drug targeting to diseased liver mediated by various receptors, including asialoglycoprotein, mannose and galactose receptor, Fc receptor, low-density lipoprotein, glycyrrhetinic, and bile acid receptor. The essential consideration is given to treating liver cancer targeting using nanoparticulate systems, proteins, viral and non-viral vectors, homing peptides and gene delivery.

CONCLUSION

Receptors based targeting approach is one such approach that was explored by researchers to develop novel formulations which can ensure site-specific drug delivery. Several receptors are on the surfaces of liver cells, which are highly overexpressed in various disease conditions. They all are helpful for the treatment of liver cancer.

Development of near-infrared imaging agents for detection of junction adhesion molecule-A protein

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Anti-junctional adhesion molecule-A (JAM-A) monoclonal antibodies (mAb) conjugated with near infra-red fluorescent dye, IR700 – as a JAM-A mAb/IR700 agent was developed.

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An in vivo JAM-A mAb/IR700-specific near infra-red imaging of human-derived prostate and breast cancer xenograft is presented.

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A single injection of the agent is diminished number of mitotic cells in cancerous tissue of mice bearing heterotopic tumors.

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Since, our agent depicts the specific accumulation within the targeted tumors, this agent may be adapted to solid tumor targeted photoimmunotherapy.

Introduction

Prostate and breast cancer are the most prevalent primary malignant human tumors globally. Prostatectomy and breast conservative surgery remain the most common definitive treatment option for the >500,000 men and women newly diagnosed with localized prostate and breast cancer each year only in the US. Morphological examination is the mainstay of diagnosis but margin under-sampling of the excised cancer tissue may lead to local recurrence. In despite of the progress of non-invasive optical imaging, there is still a clinical need for targeted optical imaging probes that could rapidly and globally visualize cancerous tissues.

Methods

Elevated expression of junctional adhesion molecule-A (JAM-A) on tumor cells and its multiple pro-tumorigenic activity make the JAM-A a candidate for molecular imaging. Near-infrared imaging probe, which employed anti-JAM-A monoclonal antibody (mAb) phthalocyanine dye IR700 conjugates (JAM-A mAb/IR700), was synthesized and used to identify and visualize heterotopic human prostate and breast tumor mouse xenografts in vivo.

Results

The intravenously injected JAM-A mAb/IR700 conjugates enabled the non-invasive detection of prostate and breast cancerous tissue by fluorescence imaging. A single dose of JAM-A mAb/IR700 reduced number of mitotic cancer cells in vivo, indicating theranostic ability of this imaging agent. The JAM-A mAb/IR700 conjugates allowed us to image a specific receptor expression in prostate and breast tumors without post-image processing.

Conclusion

This agent demonstrates promise as a method to image the extent of prostate and breast cancer in vivo and could assist with real-time visualization of extracapsular extension of cancerous tissue.

Levels of serum IgG subclasses in patients with liver disease: A retrospective study

Viral and alcoholic liver disease, drug induced liver disease (DILD), primary biliary cirrhosis (PBC) and autoimmune hepatitis (AIH) are among the most common liver diseases observed in clinical practice. These diseases lack unique clinical characteristics at the beginning of pathogenesis, which renders specific diagnosis difficult. Immunoglobulin G (IgG) subclasses are the main isoform of antibodies that can be found in the serum that serve important protective roles in immunity. The present study aimed to investigate the serum IgG subclass distribution in patients with the five common liver diseases aforementioned. The present study retrospectively recorded and analyzed the serum IgG subclass levels of different patients, who were grouped according to their clinical diagnosis. Serum IgG subclass levels were measured using immunonephelometric assays. IgG3 levels were found to be significantly increased whereas IgG4 levels were significantly decreased in patients with PBC. In patients with AIH, IgG1 levels were significantly increased. By contrast, IgG1/IgG level ratios in patients with viral liver disease were significantly increased. No clear pattern in the distribution characteristics of IgG subclasses could be observed in cohorts with alcoholic liver disease and DILD in the present study. Additionally, model for end-stage liver disease scores regarding IgG1 in patients with AIH shared a synergistic relationship. Anti-mitochondrial antibody subtype M2 (AMA-M2) and IgG3 in patients with PBC demonstrated a synergistic relationship. These results suggested that IgG subclasses may be used as biomarkers to further the understanding of liver disease, which could allow for early diagnosis.

Telbivudine on IgG-associated hypergammaglobulinemia and TGF-β1 hyperactivity in hepatitis B virus-related liver cirrhosis

As debate rumbles on about whether anti-hepatitis B virus (HBV) nucleos(t)ide analogue treatments modulate host immune system during end-stage liver diseases, we studied effects of two potent anti-HBV agents, telbivudine or entecavir, on humoral immune activities including cytokine secretion, immunoglobulin production, and IgG-Fc agalactosylation, which is known to induce proinflammatory responses, in liver cirrhosis. Serum IgG-Fc N-glycan structures in patients with HBV-related liver cirrhosis, who had received either telbivudine treatment or entecavir treatment for at least 48 weeks were analyzed using liquid chromatography tandem-mass spectrometry. Levels of cytokines and each immunoglobulin isotype were measured using enzyme-linked immunosorbent assays. Results showed that 48 weeks of entecavir treatment caused HBV DNA loss, alanine aminotransferase normalization, and an amelioration of hypergammaglobulinemia in cirrhotic patients; however, telbivudine treatment, though possessing similar efficacies on HBV suppression and an improvement in liver inflammation to entecavir treatment, did not mitigate IgG-related hypergammaglobulinemia. Levels of IgG and transforming growth factor (TGF)-β1 in sera of the cirrhotic patients before and during treatment were positively correlated. In vitro assays revealed that telbivudine treatment induced TGF-β1 expression in human macrophagic cells. Moreover, recombinant TGF-β1 treatment stimulated cell proliferation and IgG overproduction in human IgG-producing B cell lines. Finally, we found that telbivudine treatment enhanced the proportion of serum IgG-Fc agalactosylation in cirrhotic patients, which was associated with enhanced levels of TGF-β1 and IgG. In conclusion, telbivudine therapy was associated with TGF-β1 hyperactivity, IgG-related hypergammaglobulinemia, and IgG-Fc agalactosylation in HBV-related liver cirrhosis.

Protective effect of human serum amyloid P on CCl4-induced acute liver injury in mice

Human serum amyloid P (hSAP), a member of the pentraxin family, inhibits the activation of fibrocytes in culture and inhibits experimental renal, lung, skin and cardiac fibrosis. As hepatic inflammation is one of the causes of liver fibrosis, in the present study, we investigated the hepatoprotective effects of hSAP against carbon tetrachloride (CCl₄)-induced liver injury. Our data indicated that hSAP attenuated hepatic histopathological abnormalities and significantly decreased inflammatory cell infiltration and pro-inflammatory factor expression. Moreover, CCl₄-induced apoptosis in the mouse liver was inhibited by hSAP, as measured by terminal-deoxynucleotidyl transferase mediated nick-end labeling (TUNEL) assay and cleaved caspase-3 expression. hSAP significantly restored the expression of B cell lymphoma/leukemia (Bcl)-2 and suppressed the expression of Bcl-2-associated X protein (Bax) in vivo. The number of hepatocytes in early apoptosis stained with Annexin V was significantly reduced by 28–30% in the hSAP treatment group compared with the CCl₄ group, and the expression of Bcl-2 was increased, whereas the expression of Bax and cleaved caspase-3 were significantly inhibited in the hSAP pre-treatment group compared with the CCl₄ group. hSAP administration also inhibited the migration and activation of hepatic stellate cells (HSCs) in CCl₄-injured liver and suppressed the activation of isolated primary HSCs induced by transforming growth factor (TGF)-β1 in vitro. Collectively, these findings suggest that hSAP exerts a protective effect againts CCl₄-induced hepatic injury by suppressing the inflammatory response and hepatocyte apoptosis, potentially by inhibiting HSC activation.

Serum Immunoglobulin A (IgA) Level Is a Potential Biomarker Indicating Cirrhosis during Chronic Hepatitis B Infection

Background. Serum immunoglobulins (Igs) are frequently elevated in patients with chronic liver disease, but currently there is a lack of sufficient data on serum Igs in patients with chronic hepatitis B virus (CHB) infection. This study aimed to evaluate serum IgA, IgG, and IgM levels in patients with HBV-related cirrhosis and to analyze, if altered, immunoglobulin levels that were associated with cirrhosis progress. Methods. A cohort of 174 CHB patients including 104 with cirrhosis (32 decompensated and 72 compensated) and 70 without cirrhosis and 55 healthy controls were enrolled. Serum immunoglobulin levels and biochemical and virological parameters were determined in the enrollment blood samples. Results. Serum IgA levels were significantly increased in cirrhosis group compared with noncirrhosis group and healthy controls (all P < 0.001). Furthermore, serum IgA concentrations in decompensated cirrhosis patients were significantly higher than that of compensated patients (P = 0.002). Multivariate analysis suggested that serum IgA, platelets, and albumin were independent predictors for cirrhosis (all P < 0.001). Conclusions. Elevated IgA levels may function as an independent factor indicating cirrhosis, and there appears to be a strong association between increasing serum IgA level and disease progressing in patients with chronic HBV infection.

Relationship between clinical parameters and degree of liver fibrosis and risk factors for significant liver fibrosis in patients with chronic hepatitis B: A Logistic regression analysis

AIM: To investigate the relationship between the severity of fibrosis and clinical parameters in patients with chronic hepatitis B (CHB), and to analyze risk factors for significant liver fibrosis in CHB patients.

METHODS: A total of 76 biopsy-proven CHB cases treated from January 2012 to July 2015 at the Second Hospital Affiliated to Kunming Medical University were included in the study. Gender, age, blood count variables including white blood cells, hemoglobin (HB), platelet count (PLT), red blood cell distribution width (RDW), mean platelet volume (MPV), as well as albumin (ALB), globin (GLO), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (GGT), total bilirubin (TB), prothrombin time (PT) and serum HBV DNA were recorded. Relationship between these parameters and liver fibrosis stage and risk factors for significant liver fibrosis were analyzed.

RESULTS: With the increase in the severity of liver fibrosis, white blood cells, HB, PLT, and ALB gradually decreased, and RDW, GLB, AST, PT, GGT increased; all of these parameters had significant differences between the S1-S4 groups (P < 0.05). Spearman correlation analysis showed that there was a positive correlation between ALT, AST, GGT, TB, GLO, PT, RDW, MPV, age and liver stage of fibrosis, and a negative correlation between liver stage of fibrosis and ALB, white blood cells, HB, and PLT. In logistic regression analysis, PLT was identified as an independent risk factor for significant liver fibrosis in CHB.

CONCLUSION: ALT is not predictive of liver fibrosis stage. PLT is an independent risk factor for significant liver fibrosis in CHB. Liver histopathology can be recommended for CHB patients with older age, lower PLT, even though ALT is normal or only mildly elevated.

Can mean platelet volume determine the severity of liver fibrosis or inflammation in patients with chronic hepatitis B?

AIMS

We aimed to determine whether mean platelet volume (MPV) is one of the variables that determine the severity of liver fibrosis and inflammation.

MATERIALS AND METHODS

Patients with chronic hepatitis B virus (HBV) infection were divided into two groups: patients with fibrosis scores of 0-3 and 4-6 and patients with histologic activity index scores of 0-9 and 10-18 (according to the Ishak Scoring System). The independent variables determining the severity of liver fibrosis and inflammation were investigated.

RESULTS

Two hundred and thirty-eight patients were included in this retrospective study. The fibrosis scores of 29 patients (12.2%) were higher than 3. The independent variables that determined the severity of the fibrosis score were a high level of serum γ-glutamyl transferase and a low blood platelet count (odds ratio and P values were 1.016 and 0.004 for γ-glutamyl transferase, and 0.986 and 0.002 for blood platelet count). The histologic activity indexes of 38 patients (16%) were higher than 9. The independent variables determining the severity of liver inflammation were serum HBV DNA, γ-glutamyl transferase, and globulin levels and the MPV [odds ratio and P values were, respectively, 0.1001 and 0.046 for HBV DNA (×10); 1.016 and 0.004 for γ-glutamyl transferase; 2.247 and 0.039 for globulin; and 1.488 and 0.004 for the MPV]. The sensitivity, specificity, and positive predictive value and negative predictive value of the model predicting the severity of liver inflammation were 60.5, 83, 40.3, and 91.7%, respectively (area under the receiver-operating characteristic curve=0.775, P=0.0001).

CONCLUSION

MPV may provide useful information to predict the degree of liver inflammation along with other markers.

Role of resident liver cells in the pathogenesis of schistosomiasis

Pathology in schistosomiasis occurs as a result of eggs deposited in the liver by the schistosome parasite. A granulomatous reaction occurs, resulting in portal hypertension and hepatic fibrosis. Resident non-parenchymal cells within the liver take part in this process, including hepatic stellate cells, which are responsible for collagen production, and Kupffer cells, the liver macrophages involved in both host protection and in pathology. Other cells such as liver sinusoidal endothelial cells or portal fibroblasts may also be involved in this process. This review discusses the possible role of these resident liver cells in the pathology associated with schistosomiasis and provides information which may assist our understanding of the mechanisms associated with chronic liver disease in general.

[Serum globulin levels and intensity of hepatic fibrosis in patients with mansonic schistosomiasis]

BACKGROUND

A correlation between the levels of serum globulins and the hepatic fibrosis degree in chronic hepatitis was described, but reports in schistosomiasis mansoni have not been found.

OBJECTIVE

To evaluate the serum globulins and IgG levels, and periportal fibrosis intensity measured by ultrasound in patients with schistosomiasis mansoni.

METHODS

Between November, 2006 and February 2007, 41 patients which were eligible, filled them a questionnaire and had their levels of serum IgG measured by immunoturbidimetry and globulins indirectly measured by the Biuret method. The ultrasound was carried out by a single researcher, according to the Cairo and Niamey protocols.

RESULTS

The average age was 41 years old and 25 female patients (61%). Ten patients (24%) from 41 showed serum globulins levels raised and 21 (51%) presented elevated IgG levels. According to the Cairo classification, 21 patients showed grade I of fibrosis, 18 grade II and 2 grade III; and by the Niamey classification 8 showed standard C, 20 D, and 13 E. Those with grade II or III of fibrosis had higher IgG levels than the ones with grade I (P = 0.047), as well as those who showed standards D and E as compared to C (P = 0.011). There was no association between the globulins levels and the intensity of fibrosis.

CONCLUSION

In patients with schistosomiasis mansoni, an increase of the IgG serum levels was observed according to the progression from periportal fibrosis intensity, but the same was not founded with globulins levels.

Modulation of the Fcgamma receptors induced by anti-Ro and anti-La autoantibodies: observations in salivary gland cells

Only few reports have shown protein expression of the Fcgamma receptors (FcgammaRs) molecules on human salivary gland cells. In this study we investigate a possible upregulation of FcgammaRs following anti-Ro and anti-La autoantibodies treatment. Anti-Ro and anti-La autoantibodies were purified from IgG fractions obtained from 14 patients with primary Sjögren's syndrome (SS), using Sepharose 4B-Ro and Sepharose 4B-La affinity columns. Flow cytometry and RT-PCR were used to study the FCgammaRI, FCgammaRII and FCgammaRIII receptors expression and upregulation by anti-Ro and anti-La on a salivary gland cell line. The present data document that the anti-Ro and anti-La autoantibodies determine an increase of the FcgammaRs expression on salivary gland cells, and provide evidence that both the high affinity FcgammaRI and the low affinity FcgammaRII and FcgammaRIII are overexpressed. Treatment with IgG isolated from healthy donors had no effect on the basal FCgammaRs expression.

Alpha-fetoprotein and other tumour-associated antigens for immunotherapy of hepatocellular cancer

BACKGROUND

Hepatocellular carcinoma (HCC) is a leading cause of cancer death, with few treatment options for advanced disease.

OBJECTIVES

Here, we review the aetiology of HCC and focus on recent data on tumour-associated antigens (TAA) for HCC, their functions and potential use as immunological targets for immune-based therapy for HCC. In addition, we examine some aspects of antigen presentation within the liver.

RESULTS/CONCLUSIONS

alpha-Fetoprotein (AFP) has been investigated for many years as a TAA, and has been tested in recent clinical trials. More recently, additional TAA have been identified and new therapeutic approaches have been investigated which may be testable clinically in this difficult disease setting.

Starring stellate cells in liver immunology

Stellate cells are star-shaped cells located in the liver and mediate a multitude of primarily non-immunological functions. They play a pivotal role in the metabolism of vitamin A and store 80% of total body retinol. Upon activation, stellate cells differentiate to myofibroblasts for production of extracellular matrix, leading to liver fibrosis. Moreover, activated stellate cells regulate liver blood flow through vasoconstriction implicated in portal hypertension. Earlier work demonstrated stellate cell derived secretion of chemokines and cytokines such as transforming growth factor beta (TGF-beta), suggesting an association with immunological processes. Indeed, recent evidence indicated that hepatic stellate cells perform potent APC function for stimulation of NKT cells as well as CD8 and CD4 T cells. Additionally, stellate cell mediated antigen presentation induced protective immunity against bacterial infection. Current experiments reveal that the presenting ability of stellate cells is the key to antigen-dependent T cell instruction by vitamin A derived retinoic acid. Finally, future studies will show whether in the firmament of immunology stellate cells will represent fixed or falling stars.

Apoptotic hepatocyte DNA inhibits hepatic stellate cell chemotaxis via toll-like receptor 9

Apoptosis of hepatocytes results in the development of liver fibrosis, but the molecular signals mediating this are poorly understood. Degradation and modification of nuclear DNA is a central feature of apoptosis, and DNA from apoptotic mammalian cells is known to activate immune cells via Toll-like receptor 9 (TLR9). We tested if DNA from apoptotic hepatocytes can induce hepatic stellate cell (HSC) differentiation. Our data show that apoptotic hepatocyte DNA and cytidine-phosphate-guanosine oligonucleotides induced up-regulation of transforming growth factor beta1 and collagen 1 messenger RNA both in the human HSC line LX-2 and in primary mouse HSCs. These effects were opposed by TLR9 antagonists. We have recently shown that adenosine inhibits HSC chemotaxis, and we now show that apoptotic hepatocyte DNA also inhibits platelet-derived growth factor (PDGF)-mediated HSC chemotaxis. Inhibition of HSC chemotaxis by PDGF was blocked by TLR9 antagonists, and was absent in primary HSCs from mice deficient in TLR9 or the TLR adaptor molecule MyD88. Stimulation of TLR9 on HSCs blocked signaling by the PDGF signaling molecule inositol 1,4,5-triphosphate and reduced PDGF-mediated increase in cytosolic Ca(2+).

CONCLUSION

DNA from apoptotic hepatocytes acts as an important mediator of HSC differentiation by (1) providing a stop signal to mobile HSCs when they have reached an area of apoptosing hepatocytes and (2) inducing a stationary phenotype-associated up-regulation of collagen production.

Serum globulin levels in predicting the extent of hepatic fibrosis in patients with recurrent post-transplant hepatitis C infection

The progression of HCV-related disease is particularly aggressive in the post-transplantation setting. Recipients with recurrent HCV infection undergo repeated liver biopsies in order to estimate disease progression. A strong association was found between serum immunoglobulins levels and hepatic fibrosis in non-transplanted patients with chronic HCV infection. The aim of this study was to determine if serum globulin and immunoglobulins levels can predict the extent of fibrosis in patients with recurrent HCV infection. The records of 45 patients (mean age 51.6 +/- 10.5 yr; 53.3% men) with biochemical, serologic, virologic, and histological evidence of recurrent HCV infection were reviewed. Recurrence developed after a median interval of 11.7 months (range: 3-106); in 14 patients (31.1%), the recurrent infection was severe. The mean duration of follow-up was 51.4 +/- 35.4 months. A total of 96 liver biopsies were performed. The mean fibrosis score increased significantly with an increase in the number of biopsies (p < 0.0001, r = 0.44). On multivariate analysis, the only predictors of severe fibrosis were serum levels of globulin (OR: 5.97, 95% CI: 1.82-19.53; p = 0.0004) and IgG (OR: 1.003, 95% CI: 1.001-1.006; p = 0.018). On linear regression analysis, for each 0.5-g/dL increase in serum globulin level, there was a 0.22-point increase in fibrosis stage. In conclusion, serum levels of globulin and IgG can serve as a noninvasive marker of the extent of hepatic fibrosis in patients with post-transplant recurrent HCV infection, thus avoiding the need for repeated liver biopsies. These findings, if confirmed, have important implications for the prevention and treatment of fibrosis in this patient group.

Stellate cell apoptosis by a soluble mediator from immortalized human hepatocytes

Activated hepatic stellate cells (HSCs) are the major source of extracellular matrix in fibrosis and cirrhosis. In this study, we have investigated the role of hepatitis C virus (HCV) core protein induced immortalized human hepatocytes (IHH) on HSC growth. Preferential growth of IHH and apoptosis of activated human hepatic stellate cells (LX2) were observed upon coculture of these two cell types in a dual chamber or in the presence of conditioned medium (CM) from IHH. CM did not display a growth inhibitory role on other hepatic (Huh-7, HepG2, Hep3B and THLE) and non-hepatic (HeLa, MCF-7, and BHK) epithelial cells, indicating that the soluble mediator from IHH does not have a generalized effect on cell lines examined in our study. Further studies suggested that CM from IHH increased the expression of TRAIL receptors on LX2 cell surface, and induced apoptosis by a caspase dependent mechanism. Peptide mass fingerprinting of the purified soluble mediator from CM suggested that gelsolin fragments may play a role in apoptosis of LX2 cells. Taken together, our results suggested that a soluble mediator secreted from immortalized human hepatocytes plays an important role in hepatic stellate cell growth regulation.

Predictive value of serum globulin levels for the extent of hepatic fibrosis in patients with chronic hepatitis B infection

The mechanism underlying disease progression in hepatitis B virus (HBV) infection is unknown. Immunoglobulins stimulate the proliferative activity of rat hepatic stellate cells in vitro. A strong association was found between serum immunoglobulin levels and hepatic fibrosis in patients with hepatitis C virus infection. Our objective was to determine if the same index could also be used in patients with chronic HBV infection. The records of 100 patients with biochemical, serological, virological and histological evidence of chronic HBV infection were reviewed for background factors and serum globulin and immunoglobulin levels. Mean (+/-SD) patient age was 44.0 +/- 14.7 years; 80 (80%) were male. Of the factors found to be significant on univariate analysis, the only significant predictors of severe hepatic fibrosis (stage > or = 2) on multivariate analysis were serum globulin level [odds ratio (OR) 5.97, 95% confidence intervals (CI) 1.82-19.53, P = 0.0004], platelet count (OR 0.98, CI 0.97-0.99, P = 0.001), and immunoglobulin G (IgG) level (OR 1.003, CI 1.000-1.007, P < 0.042) but not IgA, alkaline phosphatase, albumin or international normalized ratio. For each increase of 0.33 mg/dL in serum globulin, there was a 0.5 point increase in the stage of hepatic fibrosis. There appears to be a strong association between levels of serum globulin and IgG and extent of hepatic fibrosis in patients with chronic HBV infection. They can serve as noninvasive markers of hepatic fibrosis and, if confirmed, have important implications for the management of patients with chronic HBV infection.