Imbalanced intrahepatic expression of interleukin 12, interferon gamma, and interleukin 10 in fulminant hepatitis B

Machine Perfusion as a Strategy to Decrease Ischemia-Reperfusion Injury and Lower Cancer Recurrence Following Liver Transplantation

Liver transplantation (LT) is a key treatment for primary and secondary liver cancers, reducing tumor burden with concurrent improvement of liver function. While significant improvement in survival is noted with LT, cancer recurrence rates remain high. Mitochondrial dysfunction caused by ischemia-reperfusion injury (IRI) is known to drive tumor recurrence by creating a favorable microenvironment rich in pro-inflammatory and angiogenic factors. Therefore, strategies that decrease reperfusion injury and mitochondrial dysfunction may also decrease cancer recurrence following LT. Machine perfusion techniques are increasingly used in routine clinical practice of LT with improved post-transplant outcomes and increased use of marginal grafts. Normothermic (NMP) and hypothermic oxygenated machine perfusion (HOPE) provide oxygen to ischemic tissues, and impact IRI and potential cancer recurrence through different mechanisms. This article discussed the link between IRI-associated inflammation and tumor recurrence after LT. The current literature was screened for the role of machine perfusion as a strategy to mitigate the risk of cancer recurrence. Upfront NMP ("ischemia free organ transplantation") and end-ischemic HOPE were shown to reduce hepatocellular carcinoma recurrence in retrospective studies. Three prospective randomized controlled trials are ongoing in Europe to provide robust evidence on the impact of HOPE on cancer recurrence in LT.

Sex-differences in the association of interleukin-10 and interleukin-12 variants with the progression of hepatitis B virus infection in Caucasians

AIM

Interleukin (IL)-10 and IL-12 contribute to immune responses against hepatitis B virus (HBV) infection. Polymorphisms in the IL-10 and IL-12A genes might affect the clinical outcome of HBV infection. We evaluated the association of IL-10 rs1800896 and rs3024490, and IL-12A rs568408 and rs2243115 with the progression of HBV infection and development of severe liver disease stages in a white European population.

METHOD

A total of 636 white European patients with chronic HBV infection, 239 individuals with spontaneous HBV surface antigen seroclearance, and 254 healthy controls were enrolled. The chronic HBV infection group included patients with hepatitis B envelope antigen (HBeAg) negative chronic hepatitis B (n = 255), with HBeAg positive chronic hepatitis B (n = 99) and with HBeAg negative HBV infection (n = 228). A total of 104 chronically infected patients were diagnosed with liver cirrhosis. Serum levels of cytokines were measured in patients with HBV infection (n = 195) and in healthy controls (n = 160).

RESULTS

In adjusted multivariate analysis, the IL-10 rs1800896 AG/GG genotypes were significantly associated with an increased probability of HBV surface antigen seroclearance (OR = 1.75, 95% CI 1.04-2.94, p = 0.034), with an increased likelihood of HBeAg negative chronic infection (OR = 1.93, 95% CI 1.05-3.54, p = 0.034) and with increased serum cytokines levels in female patients. In contrast, the IL-12A rs568408 AG/AA genotypes were independently associated with an increased risk to develop liver cirrhosis, with an OR of 1.90 (95% CI 1.07-3.39, p = 0.029) in male patients.

CONCLUSION

The current study shows a sex-related association of the IL-10 single-nucleotide polymorphism rs1800896 and IL-12A single-nucleotide polymorphism rs568408 with different stages of HBV infection and with HBV-related liver cirrhosis in white European patients.

Spred2 controls the severity of Concanavalin A-induced liver damage by limiting interferon-gamma production by CD4+ and CD8+ T cells

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Spred2^-/- mice developed exacerbated Con A-induced liver damage with increased IFNγ production.

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MEK/ERK inhibitor U0126 markedly inhibited the damage and reduced IFNγ production.

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Neutralization of IFNγ abolished the damage with down-regulated hepatic STAT1 activation.

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Depletion of CD4⁺/CD8⁺ T cells improved the damage with decreased IFNγ production.

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Transplantation of CD4⁺/CD8⁺ T cells into RAG1^-/- mice reproduced severe liver damage.

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Liver damage and IFNγ production were significantly lower in Spred2 transgenic mice.

Introduction

Mitogen-activated protein kinases (MAPKs) are involved in T cell-mediated liver damage. However, the inhibitory mechanism(s) that controls T cell-mediated liver damage remains unknown.

Objectives

We investigated whether Spred2 (Sprouty-related, EVH1 domain-containing protein 2) that negatively regulates ERK-MAPK pathway has a biological impact on T cell-mediated liver damage by using a murine model.

Methods

We induced hepatotoxicity in genetically engineered mice by intravenously injecting Concanavalin A (Con A) and analyzed the mechanisms using serum chemistry, histology, ELISA, qRT-PCR, Western blotting and flow cytometry.

Results

Spred2-deficient mice (Spred2^-/-) developed more sever liver damage than wild-type (WT) mice with increased interferon-γ (IFNγ) production. Hepatic ERK phosphorylation was enhanced in Spred2^-/- mice, and pretreatment of Spred2^-/- mice with the MAPK/ERK inhibitor U0126 markedly inhibited the liver damage and reduced IFNγ production. Neutralization of IFNγ abolished the damage with decreased hepatic Stat1 activation in Spred2^-/- mice. IFNγ was mainly produced from CD4⁺ and CD8⁺ T cells, and their depletion decreased liver damage and IFNγ production. Transplantation of CD4⁺ and/or CD8⁺ T cells from Spred2^-/- mice into RAG1^-/- mice deficient in both T and B cells caused more severe liver damage than those from WT mice. Hepatic expression of T cell attractants, CXCL9 and CXCL10, was augmented in Spred2^-/- mice as compared to WT mice. Conversely, liver damage, IFNγ production and the recruitment of CD4⁺ and CD8⁺ T cells in livers after Con A challenge were lower in Spred2 transgenic mice, and Spred2-overexpressing CD4⁺ and CD8⁺ T cells produced lower levels of IFNγ than WT cells upon stimulation with Con A in vitro.

Conclusion

We demonstrated, for the first time, that Spred2 functions as an endogenous regulator of T cell IFNγ production and Spred2-mediated inhibition of ERK-MAPK pathway may be an effective remedy for T cell-dependent liver damage.

How Machine Perfusion Ameliorates Hepatic Ischaemia Reperfusion Injury

The increasing disparity between the number of patients listed for transplantation and the number of suitable organs has led to the increasing use of extended criteria donors (ECDs). ECDs are at increased risk of developing ischaemia reperfusion injury and greater risk of post-transplant complications. Ischaemia reperfusion injury is a major complication of organ transplantation defined as the inflammatory changes seen following the disruption and restoration of blood flow to an organ—it is a multifactorial process with the potential to cause both local and systemic organ failure. The utilisation of machine perfusion under normothermic (37 degrees Celsius) and hypothermic (4–10 degrees Celsius) has proven to be a significant advancement in organ preservation and restoration. One of the key benefits is its ability to optimise suboptimal organs for successful transplantation. This review is focused on examining ischaemia reperfusion injury and how machine perfusion ameliorates the graft’s response to this.

CHI3L1 alleviate acute liver injury by inhibiting Th1 cells differentiation through STAT3 signaling pathway

Background

Acute liver injury (ALI) is a severe liver disease. Chitinase 3-like-1 (CHI3L1), a protein belonging to the glycosyl hydrolase family 18, is involved in many diseases, such as inflammatory diseases, bacterial infections, and various malignant tumors; however, the function of CHI3L1 in ALI remains unclear. The objective of this study was to evaluate the protective functions of CHI3L1 against thioacetamide (TAA)-induced ALI in mice and explore its potential mechanisms.

Methods

Data from 20 patients with ALI and 10 healthy subjects was collected. Serum CHI3L1, serum aspartate transaminase (AST), and serum alanine aminotransferase (ALT) were measured. To establish ALI mouse models, thioacetamide was intraperitoneally injected into groups of the CHI3L1-knockout (CHI3L1-KO) and wild-type (WT) mice (80 and 150 mg/kg). Recombinant CHI3L1 protein (rCHI3L1) (5 µg/kg), IFN-γ (500 ng), and WP1033 (an inhibitor of P-STAT3, 0.2 mL) were injected before TAA treatment, after which the effects were estimated. Splenic CD4+CD62L+ naive T cells were isolated from CHI3L1-KO mice and stimulated to differentiate into regulatory T (Treg) cells, T-helper 1 (Th1) cells, T-helper 2 (Th2) cells, and T-helper 17 (Th17) cells.

Results

Increased serum CHI3L1 levels were seen both in healthy subjects and post-therapy patients compared with ALI patients. CHI3L1 levels were negatively correlated with serum ALT and AST levels in ALI patients. CHI3L1-KO group showed higher serum ALT and AST levels than the WT group following TAA treatment, while tail vein injection of rCHI3L1 reduced liver tissue injury and improved Treg cell differentiation in vivo. In vitro experiment showed that knockout of CHI3L1 improved IFN-γ+ Th1 cell differentiation. Furthermore, intraperitoneal administration of IFN-γ produced more severe hepatocellular necrosis compared with rCHI3L1 injection alone. Mechanism study showed that T-box expressed in T cells (T-bet), and signal transducer and activator of transcription 3 (STAT3), play a critical role in adversely mediating the effect of CHI3L1, which is consistent with the finding that treatment with WP1033 down-regulated the differentiation of the Th1 cells in vitro and reduced severity of liver injury in vivo.

Conclusions

CHI3L1 reduced the production of IFN-γ and inhibited Th1 cell differentiation through the STAT3 signaling pathway, which could be a potential therapeutic strategy for treating ALI.

Mobilization of γδ T Cells and IL-10 Production at the Acute Phase of Hepatitis E Virus Infection in Cytomegalovirus Carriers

Alterations in the γδ T cell compartment have been reported in immunocompromised individuals infected with hepatitis E virus (HEV)-g3. We now report the analysis of blood γδ T cells from acutely HEV-infected individuals in the absence of immunosuppression. In these patients, non-Vδ2 (ND2) γδ T cells outnumbered otherwise predominant Vδ2 cells selectively in human CMV (HCMV)-seropositive patients and were higher than in HCMV^pos controls, mimicking HCMV reactivation, whereas their serum was PCR-negative for HCMV. Stimulation of their lymphocytes with HEV-infected hepatocarcinoma cells led to an HEV-specific response in γδ subsets of HCMV^pos individuals. HEV infection was associated with a lowered expression of TIGIT, LAG-3, and CD160 immune checkpoint markers on ND2 effector memory cells in HCMV^neg but not in HCMV^pos HEV patients. γδ cell lines, predominantly ND2, were generated from patients after coculture with hepatocarcinoma cells permissive to HEV and IL-2/12/18. Upon restimulation with HEV-infected or uninfected cells and selected cytokines, these cell lines produced IFN-γ and IL-10, the latter being induced by IL-12 in IFN-γ-producing cells and upregulated by HEV and IL-18. They were also capable of suppressing the proliferation of CD3/CD28-activated CD4 cells in transwell experiments. Importantly, IL-10 was detected in the plasma of 10 of 10 HCMV^pos HEV patients but rarely in controls or HCMV^neg HEV patients, implying that γδ cells are probably involved in IL-10 production at the acute phase of infection. Our data indicate that HEV mobilizes a pool of ND2 memory cells in HCMV carriers, promoting the development of an immunoregulatory environment.

Protective effects of mild hypothermia against hepatic injury in rats with acute liver failure

INTRODUCTION AND OBJECTIVES

Acute liver failure (ALF) is a severe disease which is associated with a high mortality rate. As mild hypothermia has been shown to have protective effects on the brain, this study aimed to determine whether it also provides protection to the liver in rats with ALF and to explore its underlying mechanism.

MATERIALS AND METHODS

In total, 72 rats were divided into 3 groups: control group (CG, treated with normal saline), normothermia group (NG, treated with d-galactosamine and lipopolysaccharide; d-GalN/LPS), and mild hypothermia group (MHG, treated with d-GalN/LPS and kept in a state of mild hypothermia, defined as an anal temperature of 32-35°C). The rats were examined at 4, 8, and 12h after treatment.

RESULTS

Mild hypothermia treatment significantly reduced serum alanine transaminase and aspartate transaminase levels and improved the liver condition of rats with d-GalN/LPS-induced ALF at 12h. Serum tumor necrosis factor-alpha levels were significantly lower in the MHG than in the NG at 4h, but no significant differences were observed in the interleukin-10 levels between the NG and MHG at any time. The serum and hepatic levels of high mobility group box 1 were significantly lower in the MHG than in the NG at 8 and 12h. The protein expression levels of cytochrome C and cleaved-caspase 3 in hepatic tissues were significantly lower in the MHG than in the NG at 8h.

CONCLUSION

Mild hypothermia improved the liver conditions of rats with ALF via its anti-inflammatory and anti-apoptotic effects.

Kupffer Cells Regulate Natural Killer Cells Via the NK group 2, Member D (NKG2D)/Retinoic Acid Early Inducible-1 (RAE-1) Interaction and Cytokines in a Primary Biliary Cholangitis Mouse Model

Background

Kupffer cells and natural killer (NK) cells has been identified as contributing factors in the pathogenesis of hepatitis, but the detailed mechanism of these cell types in the pathogenesis of primary biliary cholangitis (PBC) is poorly understood.

Material/Methods

In this study, polyinosinic: polycytidylic acid (poly I: C), 2-octynoic acid-bovine serum albumin (2OA-BSA) and Freund’s adjuvant (FA) were injected to establish a murine PBC model, from which NK cells and Kupffer cells were extracted and isolated. The cells were then co-cultivated in a designed culture system, and then NK group 2, member D (NKG2D), retinoic acid early inducible-1 (RAE-1), F4/80, and cytokine expression levels were detected.

Results

The results showed close crosstalk between Kupffer cells and NK cells. PBC mice showed increased surface RAE-1 protein expression and Kupffer cell cytokine secretion, which subsequently activated NK cell-mediated target cell killing via NKG2D/RAE-1 recognition, and increased inflammation. NK cell-derived interferon-γ (IFN-γ) and Kupffer cell-derived tumor necrosis factor α (TNF-α) were found to synergistically regulate inflammation. Moreover, interleukin (IL)-12 and IL-10 improved the crosstalk between NK cells and Kupffer cells.

Conclusions

Our findings in mice are the first to suggest the involvement of the NKG2D/RAE-1 interaction and cytokines in the synergistic effects of NK and Kupffer cells in PBC.

Hepatic ischemia-reperfusion injury in liver transplant setting: mechanisms and protective strategies

Hepatic ischemia-reperfusion injury is a major cause of liver transplant failure, and is of increasing significance due to increased use of expanded criteria livers for transplantation. This review summarizes the mechanisms and protective strategies for hepatic ischemia-reperfusion injury in the context of liver transplantation. Pharmacological therapies, the use of pre-and post-conditioning and machine perfusion are discussed as protective strategies. The use of machine perfusion offers significant potential in the reconditioning of liver grafts and the prevention of hepatic ischemia-reperfusion injury, and is an exciting and active area of research, which needs more study clinically.

Thymosin α1 treatment reduces hepatic inflammation and inhibits hepatocyte apoptosis in rats with acute liver failure

The present study aimed to evaluate whether thymosin α1 (Tα1) increases survival rates through the improvement of immunofunction and inhibition of hepatocyte apoptosis in rats with acute liver failure (ALF). A total of 25 rats were randomly divided into the control group (CG), the model group (MG) and the treatment group (TG). The CG received an intraperitoneal injection of saline (2 ml). The ALF rat model was established by the intraperitoneal injection of D-galactosamine (700 mg/kg) and lipopolysaccharide (10 µg/kg). The TG received an intraperitoneal injection of Tα1 (0.03 mg/kg) 1 h prior to and 30 min after modeling. The survival rates of the rats were recorded. An additional 63 rats were randomly divided into a CG (n=3), MG (n=30) and TG (n=30). Three rats were sacrificed at 3, 6, 9 and 12 h after establishment of the rat model to detect plasma alanine transaminase (ALT), aspartate transaminase (AST), total bilirubin (TBIL), tumor necrosis factor (TNF)-α and interleukin-10 (IL-10). Liver samples were stained with hematoxylin and eosin and TUNEL, and reverse transcription-quantitative polymerase chain reaction and western blot analysis were performed to detect B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) in liver tissue. The results indicated that the survival rate of the TG was significantly higher compared with that of the MG at 24 h (P<0.05). Plasma ALT, AST and TBIL in the MG and TG increased over time (3–12 h), with ALT, AST and TBIL observed to be significantly lower in the TG compared with the MG at each time-point (P<0.05). Hepatocellular necrosis, hemorrhage and inflammatory cell infiltration of ALF were aggravated over time (3–12 h) in the MG and TG. Notably, in the Tα1-treated rats, the hepatocytes appeared healthier with fewer apoptotic cells compared with those from the MG at the same time-points. Hepatocyte apoptotic index increased in the TG and MG, but was significantly lower in the TG compared with the MG at each time-point (P<0.05) in TUNEL assays. Plasma TNF-α and IL-10 in the MG and TG increased over time (3–12 h), with TNF-α observed to be significantly lower in the TG compared with the MG at each time-point (P<0.05), however, IL-10 was observed to be significantly higher in the TG compared with the MG at each time-point (P<0.05). Bax mRNA expression was significantly lower in the TG compared with the MG at each time-point (P<0.05), whereas Bcl-2 was significantly higher (P<0.05). In conclusion, Tα1 improved survival rates in an ALF rat model by downregulating TNF-α and upregulating IL-10, leading to the attenuation of hepatic inflammation and hepatocyte apoptosis.

Hepatic Ischemia/Reperfusion: Mechanisms of Tissue Injury, Repair, and Regeneration

Hepatic ischemia/reperfusion (I/R) injury is a major complication of liver surgery, including liver resection, liver transplantation, and trauma surgery. Much has been learned about the inflammatory injury response induced by I/R, including the cascade of proinflammatory mediators and recruitment of activated leukocytes. In this review, we discuss the complex network of events that culminate in liver injury after I/R, including cellular, protein, and molecular mechanisms. In addition, we address the known endogenous regulatory mediators that function to maintain homeostasis and resolve injury. Finally, we cover more recent insights into how the liver repairs and regenerates after I/R injury, a setting in which physical mass remains unchanged, but functional liver mass is greatly reduced. In this regard, we focus on recent work highlighting a novel role of CXC chemokines as important regulators of hepatocyte proliferation and liver regeneration after I/R injury.

High serum resistin associates with intrahepatic inflammation and necrosis: an index of disease severity for patients with chronic HBV infection

BACKGROUND

Studies have revealed that resistin plays a role as an intrahepatic cytokine with proinflammatory activities. This study investigated the association between serum resistin and fibrosis severity and the possible marker role of resistin in the inflammatory process of chronic hepatitis B.

METHODS

In this study, 234 subjects with HBV infection were retrospectively selected, including 85 patients with chronic hepatitis B (CHB), 70 patients with HBV-related liver cirrhosis (LC-B), and 79 patients with HBV-related liver failure (LF-B). Serum levels of resistin, IL-1, IL-6, IL-17, IL-23, TNF-α, and TGF-β1 were assayed by ELISA. Demographic and clinical characteristics of patients were extracted from clinical databases of Taihe Hospital, Hubei University of Medicine, including serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBil), and liver stiffness (LS).

RESULTS

All the selected patients with HBV infection showed significantly increased levels of serum resistin, which was rarely detectable in the healthy controls. Serum resistin levels in patients with CHB, LC-B, and LF-B were 4.119 ± 5.848 ng/mL, 6.370 ± 6.834 ng/mL, and 6.512 ± 6.076 ng/mL, respectively. Compared with the CHB group, patients with LC-B or LF-B presented with significantly higher serum levels of resistin (p < 0.01). On the other hand, all of the enrolled patients had high serum levels of IL-1, IL-6, IL-17, TNF-α, and TGF-β1, but not IL-23. Interestingly, serum levels of resistin was significantly positively correlated with serum levels of TGF-β1 in LC-B patients (R = 0.3090, p = 0.0290), with IL-17 in LC-B (R = 0.4022, p = 0.0038) and LF-B patients (R = 0.5466, p < 0.0001), and with AST (R = 0.4501, p = 0.0036) and LS (R = 0.3415, p = 0.0310) in CHB patients.

CONCLUSIONS

High serum resistin associates with intrahepatic inflammation and necrosis and may be used as an index of disease severity for patients with chronic HBV infection.

Changes in cellular proliferation and plasma products are associated with liver failure

AIM

To study the differences in immune response and cytokine profile between acute liver failure and self-limited acute hepatitis.

METHODS

Forty-six patients with self-limited acute hepatitis (AH), sixteen patients with acute liver failure (ALF), and twenty-two healthy subjects were involved in this study. The inflammatory and anti-inflammatory products in plasma samples were quantified using commercial enzyme-linked immunoassays and quantitative real-time PCR. The cellular immune responses were measured by proliferation assay using flow cytometry. The groups were divided into viral- and non-viral-induced self-limited AH and ALF. Thus, we worked with five groups: Hepatitis A virus (HAV)-induced self-limited acute hepatitis (HAV-AH), HAV-induced ALF (HAV-ALF), non-viral-induced self-limited acute hepatitis (non-viral AH), non-viral-induced acute liver failure (non-viral ALF), and healthy subjects (HC). Comparisons among HAV and non-viral-induced AH and ALF were performed.

RESULTS

The levels of mitochondrial DNA (mtDNA) and the cytokines investigated [interleukin (IL)-6, IL-8, IL-10, interferon gamma, and tumor necrosis factor] were significantly increased in ALF patients, independently of etiology (P < 0.05). High plasma mtDNA and IL-10 were the best markers associated with ALF [mtDNA: OR = 320.5 (95%CI: 14.42-7123.33), P < 0.0001; and IL-10: OR = 18.8 (95%CI: 1.38-257.94), P = 0.028] and death [mtDNA: OR = 12.1 (95%CI: 2.57-57.07), P = 0.002; and IL-10: OR = 8.01 (95%CI: 1.26-50.97), P = 0.027]. In the cellular proliferation assay, NK^bright, NKT and regulatory T cells (TReg) predominated in virus-specific stimulation in HAV-induced ALF patients with an anergic behavior in the cellular response to mitotic stimulation. Therefore, in non-viral-induced ALF, anergic behavior of activated T cells was not observed after mitotic stimulation, as expected and as described by the literature.

CONCLUSION

mtDNA and IL-10 may be predictors of ALF and death. TReg cells are involved in immunological disturbance in HAV-induced ALF.

Blockade of Retinol Metabolism Protects T Cell-Induced Hepatitis by Increasing Migration of Regulatory T Cells

Retinols are metabolized into retinoic acids by alcohol dehydrogenase (ADH) and retinaldehyde dehydrogenase (Raldh). However, their roles have yet to be clarified in hepatitis despite enriched retinols in hepatic stellate cells (HSCs). Therefore, we investigated the effects of retinols on Concanavalin A (Con A)-mediated hepatitis. Con A was injected into wild type (WT), Raldh1 knock-out (Raldh1(-/-)), CCL2(-/-) and CCR2(-/-) mice. For migration study of regulatory T cells (Tregs), we used in vivo and ex vivo adoptive transfer systems. Blockade of retinol metabolism in mice given 4-methylpyrazole, an inhibitor of ADH, and ablated Raldh1 gene manifested increased migration of Tregs, eventually protected against Con A-mediated hepatitis by decreasing interferon-γ in T cells. Moreover, interferon-γ treatment increased the expression of ADH3 and Raldh1, but it suppressed that of CCL2 and IL-6 in HSCs. However, the expression of CCL2 and IL-6 was inversely increased upon the pharmacologic or genetic ablation of ADH3 and Raldh1 in HSCs. Indeed, IL-6 treatment increased CCR2 expression of Tregs. In migration assay, ablated CCR2 in Tregs showed reduced migration to HSCs. In adoptive transfer of Tregs in vivo and ex vivo, Raldh1-deficient mice showed more increased migration of Tregs than WT mice. Furthermore, inhibited retinol metabolism increased survival rate (75%) compared with that of the controls (25%) in Con A-induced hepatitis. These results suggest that blockade of retinol metabolism protects against acute liver injury by increased Treg migration, and it may represent a novel therapeutic strategy to control T cell-mediated acute hepatitis.

Promoter methylation status and expression of PPAR-γ gene are associated with prognosis of acute-on-chronic hepatitis B liver failure

Background

Peroxisome proliferator-activated receptor gamma (PPAR-γ) has been demonstrated to be involved in anti-inflammatory reactions, but its role in acute-on-chronic hepatitis B liver failure (ACHBLF) is unclear. Therefore, DNA methylation patterns and expression level of PPAR-γ gene were detected in peripheral blood mononuclear cells (PBMCs) from 81 patients with ACHBLF, 50 patients with chronic hepatitis B (CHB), and 30 healthy controls, and the possible role of PPAR-γ in ACHBLF was analyzed.

Results

We found that aberrant PPAR-γ promoter methylation was attenuated in ACHBLF patients compared with CHB patients and was responsible for the elevated PPAR-γ expression level, which was negatively correlated with total bilirubin and international normalized ratio. Plasma level of TNF-α and IL-6 in ACHBLF patients were higher than CHB patients and healthy controls and significantly reduced in unmethylated group. ACHBLF patients with PPAR-γ promoter methylation had poorer outcomes than those without. Correspondingly, PPAR-γ messenger RNA (mRNA) level was higher in survivors than non-survivors and gradually increased in survivors with time, while remained low level in non-survivors.

Conclusions

Aberrant promoter methylation decline and PPAR-γ expression rebound occurred in ACHBLF compared with CHB and could improve prognosis of ACHBLF by negatively regulating cytokines.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-015-0149-2) contains supplementary material, which is available to authorized users.

Role of the sympathetic nervous system in carbon tetrachloride-induced hepatotoxicity and systemic inflammation

Carbon tetrachloride (CCl₄) is widely used as an animal model of hepatotoxicity and the mechanisms have been arduously studied, however, the contribution of the sympathetic nervous system (SNS) in CCl₄-induced acute hepatotoxicity remains controversial. It is also known that either CCl₄ or SNS can affect systemic inflammatory responses. The aim of this study was to establish the effect of chemical sympathectomy with 6-hydroxydopamine (6-OHDA) in a mouse model of CCl₄-induced acute hepatotoxicity and systemic inflammatory response. Mice exposed to CCl₄ or vehicle were pretreated with 6-OHDA or saline. The serum levels of aminotransferases and alkaline phosphatase in the CCl₄-poisoning mice with sympathetic denervation were significantly lower than those without sympathetic denervation. With sympathetic denervation, hepatocellular necrosis and fat infiltration induced by CCl₄ were greatly decreased. Sympathetic denervation significantly attenuated CCl₄-induced lipid peroxidation in liver and serum. Acute CCl₄ intoxication showed increased expression of inflammatory cytokines/chemokines [eotaxin-2/CCL24, Fas ligand, interleukin (IL)-1α, IL-6, IL-12p40p70, monocyte chemoattractant protein-1 (MCP-1/CCL2), and tumor necrosis factor-α (TNF-α)], as well as decreased expression of granulocyte colony-stimulating factor and keratinocyte-derived chemokine. The overexpressed levels of IL-1α, IL-6, IL-12p40p70, MCP-1/CCL2, and TNF-α were attenuated by sympathetic denervation. Pretreatment with dexamethasone significantly reduced CCl₄-induced hepatic injury. Collectively, this study demonstrates that the SNS plays an important role in CCl₄-induced acute hepatotoxicity and systemic inflammation and the effect may be connected with chemical- or drug-induced hepatotoxicity and circulating immune response.

Assessment of cytokine expression profile in acute myeloid leukemia patients before and after chemotherapy

OBJECTIVE

One of the major goals of cancer treatment is the monitoring of chemotherapeutic protocols. Quantitative and comparative cytokine expression profiling could be reliable to be used for biomarkers in deadly and fast-growing cancers such as acute myeloid leukemia (AML). The present study aims to assess and further validate cytokines with probable effects on proliferation and maturation of blood cells in AML.

MATERIALS AND METHODS

Gene expression levels of IL-1β, IL-10, IL-8, TNF-α, and IFN-γ were analyzed before and after chemotherapy and after granulocyte colony-stimulating factor (G-CSF) therapy in 46 AML patients by an in-house quantitative comparative RT-PCR method.

RESULTS

Our findings indicated that although the gene expression level of TNF-α was almost constant in all 3 samples, IL-1β, IL-8, and IL-10 expression levels showed a decrease after chemotherapy and an increase after G-CSF therapy. On the other hand, the expression level of IFN-γ had a different pattern with an increase after chemotherapy and a decrease after G-CSF therapy.

CONCLUSION

Taken together, the results of this study are in support of the idea that the analyzed cytokines could be useful biomarkers for AML treatment monitoring. However, further molecular epidemiological investigations are suggested to elaborate more cancer monitoring biomarkers.

The role of natural killer cells in autoimmune liver disease: a comprehensive review

Natural Killer (NK) cells are important players of the innate arm of the immune system and provide an early defense against pathogens and tumor-transformed cells. Peripheral blood NK (PB-NK) cells were first identified because of their ability to spontaneously kill tumor-cell targets in vitro without the need for specific antigen priming, which is the reason that they were named 'natural killer' cells. The characterization of NK cells in human tissues and body organs represented another important step forward to better understand their physiology and physiopathology. In this regard, many reports revealed over the past decade a differential anatomic distribution of NK cell subsets in several sites such as the intestine, lung, cervix, placenta and liver as well as in secondary lymphoid organs such as spleen, lymph nodes and tonsils. Among all these tissues, the liver is certainly unique as its parenchyma contains an unusually high number of infiltrating immune cells with 30-50% of total lymphocytes being NK cells. Given the constant liver intake of non-self antigens from the gastrointestinal tract via the portal vein, hepatic NK (H-NK) cells must retain a certain degree of tolerance in the context of their immune-surveillance against dangers to the host. Indeed, the breakdown of the tolerogenic state of the liver-associated immune system has been shown to induce autoimmunity. However, the role of NK cells during the course of autoimmune liver diseases is still being debated mainly because a complete characterization of H-NK cells normally resident in healthy human liver has not yet been fully disclosed. Furthermore, the differences in phenotype and functions between human and mouse H-NK cells often preclude translation of results obtained from murine models into experimental approaches to be performed in humans. Here, we provide an extensive characterization of the phenotype of H-NK cells physiologically resident in the human liver by both mentioning data available in literature and including a set of original results recently developed in our laboratory. We then review our current knowledge in regard to the contribution of H-NK cells in regulating local immune homeostasis and tolerance as well as in inducing the development of liver autoimmunity.

Alcohol dehydrogenase-specific T-cell responses are associated with alcohol consumption in patients with alcohol-related cirrhosis

Patients with alcohol-related liver disease (ALD) have antibodies directed to alcohol dehydrogenase (ADH), anti-ADH titers being associated with disease severity and active alcohol consumption. ADH-specific T-cell responses have not been characterized. We aimed to define anti-ADH cellular immune responses and their association with active alcohol consumption and disease severity. Using cultures of peripheral blood mononuclear cells (PBMCs) from 25 patients with alcohol-related cirrhosis (ARC; 12 were actively drinking or abstinent for <6 months, and 13 were abstinent for >6 months) and hepatic mononuclear cells (HMCs) from 14 patients with ARC who were undergoing transplantation, we investigated T-cell reactivity to 25 overlapping peptides representing the full human ADH protein (beta 1 subunit). ADH-specific peripheral T-cell responses were assessed by the quantification of T-cell proliferation and cytokine production and were correlated with the clinical course. In active alcohol consumers, proliferative T-cell responses targeted ADH31-95 and other discontinuous sequences in the ADH peptide, whereas only one sequence was targeted in abstinents. ADH peptides induced the production of interferon-γ (IFN-γ), interleukin-4 (IL-4), and IL-17. IL-4 production was lower in active drinkers versus abstinents, and IL-17 production was higher. Peptides inducing IFN-γ production outnumbered those inducing T-cell proliferation. The intensity of the predominantly T helper 1 (Th 1) responses directly correlated with disease severity. Similar to PBMCs in abstinents, ADH peptides induced weak T-cell proliferation and a similar level of IL-4 production in HMCs but less vigorous Th 1 and T helper 17 responses.

CONCLUSION

This suggests that Th 1 responses to ADH in ARC are induced by alcohol consumption. A Th 1/T helper 2 imbalance characterizes T-cell responses in active drinkers with ARC, whereas IL-4 production prevails in abstinents. This identifies new targets for immunoregulatory therapies in ALD patients for halting detrimental effector T-cell responses, which may encourage liver fibrogenesis and progression to end-stage liver disease.

The L60V variation in hepatitis B virus core protein elicits new epitope-specific cytotoxic T lymphocytes and enhances viral replication

Mutations in the core protein (HBc) of hepatitis B virus (HBV) are associated with aggressive hepatitis and advanced liver diseases in chronic hepatitis B (CHB). In this study, we identified the L60V variation in HBc that generates a new HLA-A2-restricted CD8(+) T cell epitope by screening an overlapping 9-mer peptide pool covering HBc and its variants. The nonameric epitope V60 was determined by structural and immunogenic analysis. The HBc L60V variation is correlated with hepatic necroinflammation and higher viral levels, and it may be associated with a poor prognosis in CHB patients. Immunization with the defined HBV epitope V60 peptide elicited specific cytotoxic T lymphocyte (CTL)-induced liver injury in HLA-A2(+) HBV transgenic mice. In addition, in vitro and in vivo experiments both demonstrated that the HBc L60V variation facilitates viral capsid assembly and increases HBV replication. These data suggest that the HBc L60V variation can impact both HBV replication and HBV-specific T cell responses. Therefore, our work provides further dissection of the impact of the HBc L60V variation, which orchestrates HBV replication, viral persistence, and immunopathogenesis during chronic viral infection.

Cytokine expression profile of dengue patients at different phases of illness

BACKGROUND

Dengue is an important medical problem, with symptoms ranging from mild dengue fever to severe forms of the disease, where vascular leakage leads to hypovolemic shock. Cytokines have been implicated to play a role in the progression of severe dengue disease; however, their profile in dengue patients and the synergy that leads to continued plasma leakage is not clearly understood. Herein, we investigated the cytokine kinetics and profiles of dengue patients at different phases of illness to further understand the role of cytokines in dengue disease.

METHODS AND FINDINGS

Circulating levels of 29 different types of cytokines were assessed by bead-based ELISA method in dengue patients at the 3 different phases of illness. The association between significant changes in the levels of cytokines and clinical parameters were analyzed. At the febrile phase, IP-10 was significant in dengue patients with and without warning signs. However, MIP-1β was found to be significant in only patients with warning signs at this phase. IP-10 was also significant in both with and without warning signs patients during defervescence. At this phase, MIP-1β and G-CSF were significant in patients without warning signs, whereas MCP-1 was noted to be elevated significantly in patients with warning signs. Significant correlations between the levels of VEGF, RANTES, IL-7, IL-12, PDGF and IL-5 with platelets; VEGF with lymphocytes and neutrophils; G-CSF and IP-10 with atypical lymphocytes and various other cytokines with the liver enzymes were observed in this study.

CONCLUSIONS

The cytokine profile patterns discovered between the different phases of illness indicate an essential role in dengue pathogenesis and with further studies may serve as predictive markers for progression to dengue with warning signs.

Severe necroinflammatory reaction caused by natural killer cell-mediated Fas/Fas ligand interaction and dendritic cells in human hepatocyte chimeric mouse

The necroinflammatory reaction plays a central role in hepatitis B virus (HBV) elimination. Cluster of differentiation (CD)8-positive cytotoxic T lymphocytes (CTLs) are thought to be a main player in the elimination of infected cells, and a recent report suggests that natural killer (NK) cells also play an important role. Here, we demonstrate the elimination of HBV-infected hepatocytes by NK cells and dendritic cells (DCs) using urokinase-type plasminogen activator/severe combined immunodeficiency mice, in which the livers were highly repopulated with human hepatocytes. After establishing HBV infection, we injected human peripheral blood mononuclear cells (PBMCs) into the mice and analyzed liver pathology and infiltrating human immune cells with flow cytometry. Severe hepatocyte degeneration was observed only in HBV-infected mice transplanted with human PBMCs. We provide the first direct evidence that massive liver cell death can be caused by Fas/Fas ligand (FasL) interaction provided by NK cells activated by DCs. Treatment of mice with anti-Fas antibody completely prevented severe hepatocyte degeneration. Furthermore, severe hepatocyte death can be prevented by depletion of DCs, whereas depletion of CD8-positive CTLs did not disturb the development of massive liver cell apoptosis.

CONCLUSION

Our findings provide the first direct evidence that DC-activated NK cells induce massive HBV-infected hepatocyte degeneration through the Fas/FasL system and may indicate new therapeutic implications for acute severe/fulminant hepatitis B.

Increased frequency of circulating Th17 cells in acute-on-chronic hepatitis B liver failure

BACKGROUND

T helper (Th) 17 cells participate in the pathogenesis of liver diseases but their exact role in acute-on-chronic hepatitis B liver failure (ACHBLF) still remains obscure.

AIMS

This present study was aimed to characterize the circulating Th17 cells and to analyze their association with disease progression in ACHBLF.

METHODS

This retrospective study consisted of 40 ACHBLF patients, 40 chronic hepatitis B (CHB) patients and 20 healthy controls. The frequency of peripheral Th17 cells and IL-17 mRNA level in peripheral blood mononuclear cells (PBMCs) were estimated by flow cytometry and relative quantitative real-time polymerase chain reaction.

RESULTS

We found that the frequency of peripheral Th17 cells, as well as the level of IL-17 mRNA in PBMCs, was significantly increased in ACHBLF patients compared with CHB patients and healthy controls. In ACHBLF patients, the frequency of Th17 cells was positively correlated with serum total bilirubin (r = 0.392, P = 0.012) and model for end-stage liver disease scores (r = 0.383, P = 0.015), but negatively correlated with prothrombin activity (r = -0.317, P = 0.046). The same trend was observed as for relative expression of IL-17. Furthermore, the frequency of Th17 cells and IL-17 mRNA level were significantly elevated in non-survivors compared with survivors in ACHBLF patients.

CONCLUSIONS

These results suggested that Th17 cells as well as IL-17 might be related with disease severity and prognosis in ACHBLF patients.

Activated lymphocytes and high liver expression of IFN-γ are associated with fulminant hepatic failure in patients

BACKGROUND & AIMS

To study immunological mechanisms of fulminant hepatic failure (FHF) derived from extensive liver lesions, 14 patients with FHF induced by different aetiologies were investigated by observance of both lymphocyte phenotyping and cytokine levels.

METHODS

Five patients bearing benign acute hepatitis B (AHB) and seven healthy liver donors (HC) were used as controls. Samples of liver and blood from both FHF patients and HC were obtained during transplantation procedures. Plasma levels of IL-1β, IL-4, IL-6, IL-8, IL-10, IFN-γ, TNF-α, MCP-1, RANTES and MIP-1α were quantified using a multiplex immunoassay. Cell characterization was carried out by flow cytometry. IFN-γ staining was performed on liver sections using immunofluorescence methods.

RESULTS

An increase of peripheral frequency of natural killer (NK) cells expressing early activation markers (CD69, HLA-DR and CD38) and adhesion molecule CD44 was observed in FHF patients. Elevated frequency of T lymphocytes CD4(+) and CD8(+) expressing CD38 and adhesion molecules CD29 and CD44 was also observed in FHF. Additionally, an increase of natural killer T cells (NKT) was detected in FHF patients. High plasma cytokine levels were not statistically different between FHF and AHB patients. In comparison to HC, a strong liver expression of IFN-γ was detected in FHF patients. The increased frequency of CD4(+) CD44(+) and IL-8 cytokine was found in patients with poor prognosis.

CONCLUSIONS

These findings indicate the involvement of NK and NKT cells as well as T lymphocytes CD4(+) and CD8(+) in the inflammatory process inducing FHF, confirmed by the high hepatic expression of IFN-γ.

New insights into the role of macrophages in adipose tissue inflammation and Fatty liver disease: modulation by endogenous omega-3 Fatty Acid-derived lipid mediators

Obesity is causally linked to a chronic state of “low-grade” inflammation in adipose tissue. Prolonged, unremitting inflammation in this tissue has a direct impact on insulin-sensitive tissues (i.e., liver) and its timely resolution is a critical step toward reducing the prevalence of related co-morbidities such as insulin resistance and non-alcoholic fatty liver disease. This article describes the current state-of-the-art knowledge and novel insights into the role of macrophages in adipose tissue inflammation, with special emphasis on the progressive changes in macrophage polarization observed over the course of obesity. In addition, this article extends the discussion to the contribution of Kupffer cells, the liver resident macrophages, to metabolic liver disease. Special attention is given to the modulation of macrophage responses by omega-3-PUFAs, and more importantly by resolvins, which are potent anti-inflammatory and pro-resolving autacoids generated from docosahexaenoic and eicosapentaenoic acids. In fact, resolvins have been shown to work as endogenous “stop signals” in inflamed adipose tissue and to return this tissue to homeostasis by inducing a phenotypic switch in macrophage polarization toward a pro-resolving phenotype. Collectively, this article offers new views on the role of macrophages in metabolic disease and their modulation by endogenously generated omega-3-PUFA-derived lipid mediators.

Glycogen synthase kinase-3 facilitates con a-induced IFN-γ-- mediated immune hepatic injury

Immune hepatic injury induced by Con A results primarily from IFN-γ-mediated inflammation, followed by hepatic cell death. Glycogen synthase kinase (GSK)-3, which acts proapoptotically and is proinflammatory, is also important for facilitating IFN-γ signaling. We hypothesized a pathogenic role for GSK-3 in Con A hepatic injury. Con A stimulation caused GSK-3 activation in the livers of C57BL/6 mice. Inhibiting GSK-3 reduced Con A hepatic injury, including hepatic necrosis and apoptosis, inflammation, infiltration of T cells and granulocytes, and deregulated expression of adhesion molecule CD54. Con A induced hepatic injury in an IFN-γ receptor 1-dependent manner. Con A/IFN-γ induced activation and expression of STAT1 in a GSK-3-dependent manner. GSK-3 facilitated IFN-γ-induced inducible NO synthase, but had limited effects on CD95 upregulation and CD95-mediated hepatocyte apoptosis in vitro. Notably, inhibiting GSK-3 decreased Con A-induced IFN-γ production in both wild-type and IFN-γ receptor 1-deficient C57BL/6 mice. In Con A-activated NKT cells, GSK-3 was also activated and was required for nuclear translocation of T-box transcription factor Tbx21, a transcription factor of IFN-γ, but it was not required for CD95 ligand expression or activation-induced cell death. These results demonstrate the dual and indispensable role of GSK-3 in Con A hepatic injury by facilitating IFN-γ-induced hepatopathy.

Immune Augmentation of Single Contact Hepatitis B Vaccine by Using PLGA Microspheres as an Adjuvant

The present study was aimed to replace the alum type adjuvant for hepatitis B vaccine. The hepatitis B vaccine was encapsulated in poly (DL-lactide-co-glycolide) microspheres by solvent evaporation technique. The formulated microspheres were characterized in terms of morphology, particle size analysis, in vitro release study and in vivo immune response in male Wistar rats. The FT IR spectrum illustrates the characteristics bands of poly (DL-lactide-co-glycolide) microspheres and hepatitis B vaccine at 1750 cm(-1) and 1650 cm(-1), respectively. The hepatitis B vaccine loaded poly (DL-lactide-co-glycolide) microspheres were able to release antigens till day 42. Significant enhancement of specific antibodies to HBsAg was produced till day 90 after a single administration of HBsAg encapsulated poly (DL-lactide-co-glycolide) microspheres. However, the conventional alum adsorbed hepatitis B vaccine was not found to produce any significant specific antibody levels till day 90 after a single dose. The results showed that poly (DL-lactide-co-glycolide) microspheres show potential as an adjuvant for hepatitis B vaccine.

Activated IL-23/IL-17 pathway closely correlates with increased Foxp3 expression in livers of chronic hepatitis B patients

Background

Foxp3 protein plays a critical role in mediating the inflammatory response and can inhibit the proinflammatory IL-23/IL-17 pathway. However, the molecular interplay of Foxp3 and the IL-23/IL-17 pathway in patients with chronic hepatitis B (CHB) remains unclear. To this end, we analyzed the expression patterns of Foxp3- and IL-23/IL-17 pathway-related proinflammatory cytokines in 39 patients with acute-on-chronic liver failure, 71 patients with CHB and 32 healthy controls.

Results

Foxp3 expression was found to be elevated in and mainly expressed by the CD4⁺ T cell sub-population of peripheral blood mononuclear cells and liver tissues of patients with hepatitis B. The intrahepatic expression of Foxp3 strongly correlated with the copies of HBV DNA and the concentration of surface antigen, HBsAg. IL-23/IL-17 pathway-related proinflammatory cytokines were also found to be significantly increased in patients' liver tissues, as compared to healthy controls. Moreover, Foxp3 expression was strikingly correlated with the production of these cytokines in liver tissues of CHB patients.

Conclusions

The closely-correlated increase of Foxp3 and IL-23/IL-17 pathway activity in HBV-infected livers suggests that the proinflammatory IL-23/IL-17 pathway had not been effectively suppressed by the host immune machinery, such as Treg (Foxp3) cells. Constitutive activation of the IL-23/17 pathway, thus, may support the chronic hepatitis B state.

Nucleoside analogue can improve the long-term prognosis of patients with hepatitis B virus infection-associated acute on chronic liver failure

BACKGROUND

The prognosis of patients with hepatitis B virus (HBV)-associated acute on chronic liver failure (ACLF) is extremely poor.

AIM

This study was designed to evaluate the efficacy and safety of nucleoside analogue treatment of patients with HBV-associated ACLF.

METHODS

We used a retrospective review of eligible patients from April 2006 to December 2008. Eligible subjects received 0.5 mg entecavir daily until October 2009 (group A), 100 mg lamivudine daily until October 2009 (group B), or no nucleoside analogue (group C). The primary endpoints were three-month survival and the rate of recurrence of HBV-associated ACLF. The secondary endpoints were HBV DNA levels, liver function, the model of end-stage liver disease (MELD) score, and adverse events.

RESULTS

A total of 104 consecutive patients were recruited, and 33, 34, and 37 patients were randomly allocated to groups A, B, and C, respectively. Although no significant difference in three-month survival was observed, levels of HBV DNA and rates of recurrence of HBV-associated ACLF were lower. Liver function and MELD score were not significantly improved despite significantly reduced HBV DNA levels.

CONCLUSIONS

These data indicated that nucleoside analogue treatment did not improve the short-term prognosis of patients with HBV-associated ACLF although it was efficacious and safe in the management of HBV DNA levels. Intriguingly and importantly, continuous nucleoside analogue treatment can significantly reduce the rate of recurrence, which might be indicative of the further benefit of long-term survival.

Management of hepatitis B in special patient populations

Hepatitis B virus is a common cause of acute liver failure. It can be especially problematic in patients coinfected with hepatitis C, hepatitis D or human immunodeficiency virus. In addition, immunosuppression-associated hepatitis B reactivation is being increasingly recognized following chemotherapy, biologic therapy, and organ transplantation. This article highlights treatment options in these special populations.

Acute liver failure: mechanisms of immune-mediated liver injury

Acute liver failure (ALF) is a syndrome of diverse aetiology, including hepatic encephalopathy, renal, cardiac and pulmonary failures, which result in a rapid loss of hepatic function. The mechanisms of liver injury contributing to ALF can be summarized into two categories: direct damage and immune-mediated liver injury. This review summarizes current concepts of immune-mediated liver injury from both clinical studies and animal models. We highlight immune responses of ALF from the liver injury perspective, which combines a variety of molecular and cellular mechanisms, particularly, the contribution of cytokines and the innate immune system. Hepatic and circulating inflammatory cytokines play a significant role in the pathophysiology of ALF including hepatocyte necrosis, extrahepatic complications and hepatocyte regeneration. Overproduction of cytokines, if unchecked, is hazardous to the host and may cause severe outcomes. Measuring pro-inflammatory cytokines in ALF may be of value for predictors of outcome. Innate and adaptive immune systems both involved in ALF contribute to immune-mediated liver injury. The innate immune response is activated much more rapidly compared with adaptive immunity, particularly in acute liver injury where the host has little time to trigger an effective adaptive immune response. From this point of view, the innate immune system may make a more profound contribution than the adaptive immune system. Furthermore, immune responses crosstalk with other physiological or pathophysiological factors, for example, coagulation factors which in turn determine the outcome of ALF and these are discussed.

N-acetylcysteine attenuates cerebral complications of non-acetaminophen-induced acute liver failure in mice: antioxidant and anti-inflammatory mechanisms

N-acetylcysteine (NAC) is an effective antidote to treat acetaminophen (APAP)-induced acute liver failure (ALF). NAC is hepatoprotective and prevents the neurological complications of ALF, namely hepatic encephalopathy and brain edema. The protective effect of NAC and its mechanisms of action in ALF due to other toxins, however, are still controversial. In the present study, we investigated the effects of NAC in relation to liver pathology, hepatic and cerebral glutathione, plasma ammonia concentrations, progression of encephalopathy, cerebral edema, and plasma proinflammatory cytokines in mice with ALF resulting from azoxymethane (AOM) hepatotoxicity, a well characterized model of toxic liver injury. Male C57BL/6 mice were treated with AOM (100 microg/g; i.p.) or saline and sacrificed at coma stage of encephalopathy in parallel with AOM mice administered NAC (1.2 g/kg; i.p.). AOM administration led to hepatic damage, significant increase in plasma transaminase activity, decreased hepatic glutathione levels and brain GSH/GSSG ratios as well as increased expression of plasma proinflammatory cytokines. NAC treatment of AOM mice led to reduced hepatic damage and improvement in neurological function, normalization of brain and hepatic glutathione levels as well as selective attenuation in expression of plasma proinflammatory cytokines. These findings demonstrate that the beneficial effects of NAC in experimental non-APAP-induced ALF involves both antioxidant and anti-inflammatory mechanisms.

Expression of urotensin II and its receptor in human liver cirrhosis and fulminant hepatic failure

OBJECTIVES

Urotensin II [U-II] plasma levels are increased in liver cirrhosis [LC] and are discussed as an important mediator of portal hypertension since the U-II antagonist palosuran has beneficial effects on portal hypertension by increasing splanchnic resistance. Nevertheless, no data are available on the intrahepatic expression of U-II and its receptor [UT] in humans.

METHODS

U-II and UT expression were analyzed in the livers of patients with LC, fulminant hepatic failure [FHF], and normal controls [NC] using immunohistochemistry.

RESULTS

Both U-II and UT were expressed in the liver on endothelial cells from arteries, veins, and bile ducts as well as on Kupffer cells. In LC, the total number of U-II-expressing cells was 20% lower compared to NC (P < 0.001), while expression of UT did not differ between LC and NC. In contrast, significant enhanced number of U-II and UT positive cells were found in FHF compared to LC and NC (P < 0.001). U-II and UT expression was also found in portal veins, without differences between LC and NC.

CONCLUSIONS

Our data demonstrate that U-II and UT are not elevated in human cirrhotic livers but are in livers of patients with FHF.

Host immunity influences disease progression and antiviral efficacy in humans infected with hepatitis B virus

Hepatitis B virus (HBV) infection can lead to several severe liver diseases, including hepatitis, cirrhosis and hepatocellular carcinoma, although the underlying mechanisms responsible for the clinical outcome have not been well characterized. In this review, we retrospectively examine the history of immunological responses to HBV infection and summarize the current understanding of innate and adaptive immunity in the context of HBV-associated liver disease. Recent data indicate that the interaction between HBV and the host immune response not only substantially drives disease progression, but also significantly influences antiviral efficacy in HBV-infected individuals. Advances in the field have provided insight into the immunopathology of HBV infection. Based on the characteristics of host immune responses in patients with HBV infection, a 'climbing slope hypothesis' is proposed to suggest that therapeutic strategies aimed at modulating the immune activity of the host may represent a complementary approach to antiviral drug treatment for the management of chronically HBV-infected patients.

Eosinophils involved in fulminant hepatic failure are associated with high interleukin-6 expression and absence of interleukin-5 in liver and peripheral blood

BACKGROUND/AIMS

Although eosinophils are considered to play an important role in the pathogenesis of various parasitic, allergic and autoimmune digestive diseases, their role in fulminant hepatic failure (FHF) is unknown. Our contribution was to identify and quantify eosinophils and cytokine levels [interleukin (IL)-6, IL-5 and macrophage inflammatory protein (MIP)-1alpha] in liver parenchyma and peripheral blood from FHF patients at pre- and post-transplantation steps.

METHODS

Histochemical methods were used to identify/quantify eosinophils in liver samples. Liver and plasma cytokine levels were quantified using immunofluorescence methods.

RESULTS

Fulminant hepatic failure patients showed a high number of intrahepatic eosinophils concomitant with an increased expression of IL-6, besides the IL-6-positive eosinophils associated with the lack of IL-5. Also, an increased number of eosinophils and soluble IL-6 and MIP-1alpha with a low expression of IL-5 in peripheral blood at the pretransplantation step was observed.

CONCLUSIONS

The increased number of intrahepatic eosinophils, besides the high production of IL-6, may be involved in liver dysfunction. In addition, the low presence of IL-5 in liver and peripheral blood may represent a particular pattern of eosinophil behaviour in human liver failure, which may also involve MIP-1alpha. Further ex vivo studies are necessary to evaluate the specific role of eosinophils in FHF.

A synergistic interferon-gamma production is induced by mouse hepatitis virus in interleukin-12 (IL-12)/IL-18-activated natural killer cells and modulated by carcinoembryonic antigen-related cell adhesion molecules (CEACAM) 1a receptor

The production of interferon-gamma (IFN-gamma) by infiltrating natural killer (NK) cells in liver is involved in the control of mouse hepatitis virus (MHV) infection. The objectives of this study were to identify the mechanisms used by MHV type 3 to modulate the production of IFN-gamma by NK cells during the acute hepatitis in susceptible C57BL/6 mice. Ex vivo and in vitro experiments revealed that NK cells, expressing carcinoembryonic antigen-related cell adhesion molecules (CEACAM) 1a (the MHV receptor), can produce a higher level of IFN-gamma in the presence of both L2-MHV3 and interleukin-12 (IL-12)/IL-18. The synergistic production of IFN-gamma by NK cells depends on viral replication rather than viral fixation only, because it is inhibited or not induced in cells infected with ultraviolet-inactivated viruses and in cells from Ceacam1a(-/-) mice infected with virulent viruses. The synergistic IFN-gamma production involves the p38 mitogen-activated protein kinase (MAPK) rather than the extracellular signal-regulated kinase-1/2 MAPK signalling pathway. However, the signal triggered through the engagement of CEACAM1a decreases the production of IFN-gamma, when these molecules are cross-linked using specific monoclonal antibodies. These results suggest that control of acute hepatitis by IFN-gamma-producing NK cells may depend on both production of IL-12 and IL-18 in the liver environment and viral infection of NK cells.

Severe dendritic cell perturbation is actively involved in the pathogenesis of acute-on-chronic hepatitis B liver failure

BACKGROUND/AIMS

Functionally impaired dendritic cells (DCs) play important roles in suppressing host immune responses and facilitating viral persistence in chronic hepatitis B virus (HBV) infection. However, little is known regarding the status of intrahepatic DCs in HBV infection.

METHODS

Based on availability, 11 recipient liver samples were obtained from acute-on-chronic hepatitis B liver failure (ACHBLF) patients who had undergone liver transplantation. The frequencies, phenotypes, and functions of intrahepatic DC subsets were analyzed.

RESULTS

Both plasmacytoid dendritic cells (pDCs) and myeloid dendritic cells (mDCs) extensively infiltrated the liver of the ACHBLF patients and expressed mature phenotypes therein. In particular, activated hepatic pDCs produced interferon (IFN)-alpha, which subsequently induced interleukin (IL)-12 and IL-10 production via toll-like receptor-9 ligation in liver-infiltrating lymphocytes cultured in vitro. However, blockade of IFN-alpha production significantly reduced the cytokine production of the LILs. Further, a significantly low frequency of peripheral pDCs and highly reduced IFN-alpha production were observed in a large cohort of the ACHBLF patients, particularly in the non-survivors. Moreover, a persistently upregulated expression of hepatic IFN-alpha-associated genes was observed in the ACHBLF patients during disease progression.

CONCLUSIONS

Activated pDCs accumulated in large numbers in the liver of the ACHBLF patients and regulated local immune responses in chronic HBV infection.

Activated protein C up-regulates IL-10 and inhibits tissue factor in blood monocytes

The protective effect of recombinant activated protein C therapy in patients with severe sepsis likely reflects the ability of recombinant activated protein C to modulate multiple pathways implicated in sepsis pathophysiology. In this study, we examined the effects of recombinant activated protein C on the anti-inflammatory cytokine IL-10 and on the procoagulant molecule tissue factor (TF) in LPS-challenged blood monocytes. Treatment of LPS-stimulated monocytes with recombinant activated protein C resulted in an up-regulation of IL-10 protein production and mRNA synthesis. The up-regulation of IL-10 required the serine protease activity of recombinant activated protein C and was dependent on protease-activated receptor-1, but was independent of the endothelial protein C receptor. At the intracellular level, p38 MAPK activation was required for recombinant activated protein C-mediated up-regulation of IL-10. We further observed that incubation of LPS-stimulated monocytes with recombinant activated protein C down-regulated TF Ag and activity levels. This anticoagulant effect of recombinant activated protein C was dependent on IL-10 since neutralization of endogenously produced IL-10 abrogated the effect. In patients with severe sepsis, plasma IL-10 levels were markedly higher in those treated with recombinant activated protein C than in those who did not receive recombinant activated protein C. This study reveals novel regulatory functions of recombinant activated protein C, specifically the up-regulation of IL-10 and the inhibition of TF activity in monocytes. Our data further suggest that these activities of recombinant activated protein C are directly linked: the recombinant activated protein C-mediated up-regulation of IL-10 reduces TF in circulating monocytes.

Cytokine profiles in acute liver failure treated with albumin dialysis

Cytokines are released within the liver in response to hepatic injury, and acute liver failure (ALF) triggers systemic inflammation. Pro-inflammatory (tumor necrosis factor-alpha [TNF-alpha] and interleukin-8 [IL-8]) and anti-inflammatory (interleukin-10 [IL-10] and interleukin-6 [IL-6]) cytokines and the lymphocyte activation marker (interleukin-2-soluble receptor alpha chain [IL-2sRalpha]) were monitored in 49 ALF patients considered for liver transplantation and treated with albumin dialysis (molecular adsorbent recirculating system [MARS]). Twenty-six patients were categorized by clinical outcome as "good" (native liver recovered) and 23 as "poor" (patient bridged to liver transplantation or deceased). MARS did not clearly affect cytokine profiles during treatment; only IL-10 levels decreased in the whole patient population and mostly in patients with the worst prognosis. In the good outcome group, IL-8 and IL-6 levels decreased during treatment; on the contrary, in poor outcome patients IL-6 levels even increased. Initial IL-2sRalpha levels were higher in poor outcome patients relative to the good outcome subset. Cytokine profiles seem to differ in ALF according to patient outcome. A deeper understanding of cytokine patterns during pathogenesis could reveal prognostic markers and aid the development of immunomodulating ALF therapies.

Association of cytokine genetic polymorphism with hepatitis B infection evolution in adult patients

The infection by the hepatitis B virus (HBV) has different forms of evolution, ranging from self-limited infection to chronic hepatic disease. The objective of this study was to evaluate the influence of cytokine genetic polymorphisms in the disease evolution. The patients were divided into two groups, one with chronic HBV (n = 30), and the other with self-limited infection (n = 41). The genotyping for TNF (-308), TGFB1 (+869, +915), IL-10 (1082, -819, and -592), IL-6 (-174), and IFNG (+874) was accomplished by the PCR-SSP (polymerase chain reaction with sequence specific primers technique using the One Lambda kit. Although no statistically significant differences were found between the groups, the combination of TNF -308GG and IFNG +874TA was found in a lower frequency in chronic patients than in individuals with self-limited infection (26.7 versus 46.3%; P = 0.079; OR = 0.40; IC95% = 0.14-1.11). In chronic patients with histological alterations it was not observed the genotype TGFB1+869 C/C, against 24.4% in the self limited infection group (100 versus 75.6%; P = 0.096; OR = 7.67; IC95% = 0.42-141.63). Further studies in other populations, and evaluation of a greater number of individuals could contribute for a better understanding of the cytokine genetic polymorphism influence in HBV infection evolution.

Interleukin-17 as a new marker of severity of acute hepatic injury

AIM

To determine cytokines associated with the progression of acute hepatic injury (AHI), we comprehensively evaluated the serum levels of 17 cytokines.

METHODS

We simultaneously measured serum levels of 17 cytokines on admission using a newly developed suspension array protein assay system in 51 patients with AHI, including 15 conventional AHI (CAHI), 15 severe AHI (SAHI) and 21 fulminant hepatic failure (FHF).

RESULTS

Interleukin (IL)-6, IL-8 and IL-17 levels were significantly different among the three disease types as determined by one-way analysis of variance, and only the IL-17 level showed a significant elevation in SAHI and FHF than in CAHI. Namely, the IL-17 levels in SAHI and FHF patients were 4.4 (2.0-11.0) (mean [1 .s.d. range]) and 5.6 (2.0-18.5) pg/mL, respectively, whereas all CAHI patients showed levels lower than the lower limit of detection (2.0 pg/mL). In multiple regression analysis for each factor of model for end-stage liver disease (MELD) score, only IL-10 level was selected as the significant independent variable for total bilirubin level, only IL-17 level for prothrombin time, and TNF-alpha and IL-1beta levels for creatinine level.

CONCLUSION

These data suggest the usefulness of serum IL-17 level in evaluating the severity of AHI, thus emphasizing the necessity for the basic investigation of the pathological role of IL-17 in acute hepatitis.

Altered immune function of monocytes in different stages of patients with acute on chronic liver failure

The aim of this study was to investigate the characteristics of the immune function of monocytes in different stages of the patients with acute on chronic liver failure (ACLF). Human leucocyte antigen (HLA)-DR and Toll-like receptor 4 (TLR-4) expression on monocytes in early and late stages of acute on chronic liver failure were detected by flow cytometry. The secretion function of monocytes was measured by cytometric bead array. Compared with healthy controls, the levels of HLA-DR expression on monocytes in patients with chronic hepatitis B, liver cirrhosis and acute on chronic liver failure were gradually decreased, especially in the late stage of acute on chronic liver failure (P < 0.001). TLR-4 expression on monocytes in patients with liver cirrhosis and acute on chronic liver failure were higher than the healthy controls. The concentrations of interleukin (IL)-1beta, tumour necrosis factor (TNF)-alpha and IL-12p70 in early-stage ACLF were significantly higher compared with healthy controls and lower in late-stage ACLF (P < 0.01, 0.05). However, a significantly lower amount of IL-10 was found on monocytes in early-stage ACLF than that of late-stage ACLF and healthy controls (P < 0.01). Monocyte HLA-DR expression in patients who died was significantly lower compared with patients who survived in the early and late stages of ACLF (P < 0.01). The dynamic detection of HLA-DR expression or cytokines secreted from monocytes could contribute to the estimation of the status of the immune function of patients with acute on chronic liver failure.

Increased serum and hepatic tissue levels of interleukin-18 in patients with fulminant hepatic failure

BACKGROUND

Fulminant hepatic failure is a serious clinical condition associated with a high mortality rate. Interleukin (IL)-18 is a pro-inflammatory cytokine that is associated with several inflammatory diseases. The purpose of the present paper was therefore to investigate whether IL-18 is elevated in patients with fulminant hepatic failure.

METHODS

Serum levels of IL-18 were measured in patients with fulminant hepatic failure before and after liver transplantation. Native liver tissue samples were collected and the tissue levels of IL-18 were determined. Liver tissues were stained immunohistochemically with antihuman IL-18 antibody. The serum levels of IL-1beta, IL-6, IL-8, IL-12, interferon-gamma, and tumor necrosis factor-alpha were also determined in patients with fulminant hepatic failure before and after liver transplantation.

RESULTS

Elevated levels of IL-18 in serum and hepatic tissue were observed in patients with fulminant hepatic failure. Native liver tissue samples were immunohistochemically positive for IL-18. Interleukin-18 levels were markedly reduced after liver replacement. No other inflammatory cytokines were substantially elevated in patients with fulminant hepatic failure.

CONCLUSION

The serum levels of IL-18 levels are elevated much more than those of other cytokines in patients with fulminant hepatic failure.

Novel mfgl2 antisense plasmid inhibits murine fgl2 expression and ameliorates murine hepatitis virus type 3-induced fulminant hepatitis in BALB/cJ mice

Our previous reports, both experimental and human studies, have shown the importance of fibrinogen-like protein-2 (fgl2) prothrombinase in the development of fulminant viral hepatitis, a disease with a mortality of more than 80% in cases lacking immediate organ transplantation. To interfere with this potentially effective target, a 322-bp mouse fgl2 (mfgl2) antisense plasmid complementary to the exon 1 sequence of the gene, including the translation initiation site AUG, was successfully constructed. A dose-dependent inhibitory effect on mfgl2 expression by mfgl2 antisense plasmid was observed in interferon-gamma-treated RAW 264.7 cells. On hydrodynamic delivery, mfgl2 antisense plasmid significantly reduced mfgl2 expression in vivo; markedly ameliorated inflammatory cell infiltration, fibrin deposition, and hepatocyte necrosis; prolonged the survival time period; and elevated the survival rate among BALB/cJ mice with murine hepatitis virus type 3-induced fulminant hepatitis. This study may provide an effective way to interfere with the potential therapeutic target fgl2 gene for fulminant viral hepatitis and other diseases with similar pathological characteristics of microcirculation disorders, including acute rejection of xeno- or allograft transplantation and fetal loss syndrome, in which studies show fgl2 plays an important role.

Novel mfgl2 antisense plasmid inhibits murine fgl2 expression and ameliorates murine hepatitis virus type 3-induced fulminant hepatitis in BALB/cJ mice

Our previous reports, both experimental and human studies, have shown the importance of fibrinogen-like protein-2 (fgl2) prothrombinase in the development of fulminant viral hepatitis, a disease with a mortality of more than 80% in cases lacking immediate organ transplantation. To interfere with this potentially effective target, a 322-bp mouse fgl2 (mfgl2) antisense plasmid complementary to the exon 1 sequence of the gene, including the translation initiation site AUG, was successfully constructed. A dose-dependent inhibitory effect on mfgl2 expression by mfgl2 antisense plasmid was observed in interferon-gamma-treated RAW 264.7 cells. On hydrodynamic delivery, mfgl2 antisense plasmid significantly reduced mfgl2 expression in vivo; markedly ameliorated inflammatory cell infiltration, fibrin deposition, and hepatocyte necrosis; prolonged the survival time period; and elevated the survival rate among BALB/cJ mice with murine hepatitis virus type 3-induced fulminant hepatitis. This study may provide an effective way to interfere with the potential therapeutic target fgl2 gene for fulminant viral hepatitis and other diseases with similar pathological characteristics of microcirculation disorders, including acute rejection of xeno- or allograft transplantation and fetal loss syndrome, in which studies show fgl2 plays an important role.