Gene expression of TNF-receptors in peripheral blood mononuclear cells of patients with alcoholic cirrhosis

Summary of the 2016 Alcohol and Immunology Research Interest Group (AIRIG) meeting

On November 18, 2016 the 21st annual Alcohol and Immunology Research Interest Group (AIRIG) meeting was held at the Center for Translational Research and Education at Loyola University Chicago's Health Sciences Campus in Maywood, IL. The 2016 meeting focused broadly on alcohol and inflammation, epigenetics, and the microbiome. The four plenary sessions of the meeting were Alcohol, Inflammation, and Immunity; Alcohol and Epigenetics; Alcohol, Transcriptional Regulation, and Epigenetics; and Alcohol, Intestinal Mucosa, and the Gut Microbiome. Presentations in all sessions of the meeting explored putative underlying causes for chronic diseases and mortality associated with alcohol consumption, shedding light on future work and potential therapeutic targets to alleviate the negative effects of alcohol misuse.

Heavy Alcohol Consumption with Alcoholic Liver Disease Accelerates Sarcopenia in Elderly Korean Males: The Korean National Health and Nutrition Examination Survey 2008-2010

Background and Aim

Although a few studies have reported that sarcopenia is associated with alcoholic liver disease (ALD), no studies have investigated this association in a large sample representative of the elderly Korean population.

Methods

This was a cross-sectional study that used data from the Fourth and Fifth Korean National Health and Nutrition Examination Surveys (KNHANES) on subjects aged 65 years and older. Sarcopenia was defined as a skeletal muscle index (SMI) more than 1 SD below the gender-specific mean for young adults; SMI was calculated as the appendicular muscle mass divided by height squared (ASM/Ht²). Heavy alcohol consumption was defined as consuming at least 210 g/week, and elevated liver enzymes were defined as alanine aminotransferase levels of at least 32 U/L or aspartate aminotransferase levels of at least 34 U/L. ALD was defined as heavy alcohol consumption and elevated liver enzymes.

Results

The mean age of the 1,151 elderly males was 71.6 ± 0.2 years, and the prevalence of heavy alcohol consumption was 11.8% (136 subjects). SMI did not differ between the non-heavy and heavy alcohol consumer groups (7.1 ± 0.0 kg/m² vs. 7.3 ± 0.1 kg/m², respectively, P = 0.145). However, after stratifying by the presence of liver disease and heavy alcohol consumption and adjusting for other confounders in the multivariate logistic regression, SMI was significantly lower among heavy alcohol consumers with ALD (all P < 0.05). Additionally, two-way ANOVA showed a significant interaction between heavy alcohol consumption and liver disease (P = 0.011).

Conclusion

Sarcopenia was accelerated in the elderly male ALD group, with a significant interaction between alcohol consumption and liver disease.

Soluble TNF-alpha-receptors I are prognostic markers in TIPS-treated patients with cirrhosis and portal hypertension

Background

TNFα levels are increased in liver cirrhosis even in the absence of infection, most likely owing to a continuous endotoxin influx into the portal blood. Soluble TNFα receptors (sTNFR type I and II) reflect release of the short-lived TNFα, because they are cleaved from the cells after binding of TNFα. The aims were to investigate the circulating levels of soluble TNFR-I and -II in cirrhotic patients receiving TIPS.

Methods

Forty-nine patients with liver cirrhosis and portal hypertension (12 viral, 37 alcoholic) received TIPS for prevention of re-bleeding (n = 14), therapy-refractory ascites (n = 20), or both (n = 15). Portal and hepatic venous blood was drawn in these patients during the TIPS procedure and during the control catheterization two weeks later. sTNFR-I and sTNFR-II were measured by ELISA, correlated to clinical and biochemical characteristics.

Results

Before TIPS insertion, sTNFR-II levels were lower in portal venous blood than in the hepatic venous blood, as well as in portal venous blood after TIPS insertion. No significant differences were measured in sTNFR-I levels. Hepatic venous levels of sTNFR-I above 4.5 ng/mL (p = 0.036) and sTNFR-II above 7 ng/mL (p = 0.05) after TIPS insertion were associated with decreased survival. A multivariate Cox-regression survival analysis identified the hepatic venous levels of sTNFR-I (p = 0.004) two weeks after TIPS, and Child score (p = 0.002) as independent predictors of mortality, while MELD-score was not.

Conclusion

Hepatic venous levels of sTNFR-I after TIPS insertion may predict mortality in patients with severe portal hypertension.

Alcohol, liver, systemic inflammation and skin: a focus on patients with psoriasis

Emerging evidence suggests that excessive alcohol consumption is associated with psoriasis. In alcoholics, antipsoriatic treatments are less efficient, but more toxic and an additional challenge is poor therapeutic compliance. There is a correlation between excess alcohol intake and increased risk of infections, but on the other hand alcohol and its metabolites can trigger a persistent systemic inflammation, mediated by pro-inflammatory cytokines released from activated Kupffer cells in the liver and from monocytes in the circulation. Ethanol and its metabolites can also enhance lymphocyte and keratinocyte activation and proliferation and can increase the mRNA levels of genes characteristic for proliferating keratinocytes. In this review, we discuss the mechanisms by which alcohol contributes to psoriasis development focusing on liver, systemic inflammation and skin.

Does the simultaneous tumor necrosis factor receptor 2, tumor necrosis factor promoter gene polymorphism represent a higher risk for alcoholic liver disease?

BACKGROUND AND AIM

Tumor necrosis factor alpha (TNF-alpha) is a proinflammatory cytokine that seems to play a crucial role in the pathogenesis of alcoholic liver disease (ALD). TNF-alpha exerts its effects by binding to specific receptors (TNFR); the polymorphism of TNFRII T587G has been associated with increased TNF apoptotic response and its presence may increase the risk to develop liver disease. The aim of this study was to evaluate the prevalence of the TNF-alpha G238A promoter and TNFRII polymorphisms, individually or simultaneously, in ALD.

METHODS

TNF-alpha G238A and TNFRII T587G polymorphisms were studied in 103 unrelated patients with ALD (biopsy confirmed or clinical evidence) and in 76 heavy drinkers without liver disease (NLD). Single nucleotide polymorphism gene was detected by a polymerase chain reaction-restriction fragment length polymorphisms method. All patients had, at least, a 5 year history of alcohol consumption greater than 80 g/day.

RESULTS

TNF-alpha G238A allele frequency was similar in both groups. TNFRII T587G allele frequency was slightly higher in the ALD group than in the NLD group (21 vs. 18%, P=NS). TNF-alpha G238A and TNFRII T587G were simultaneously present in six ALD patients and in none of NLD patients (P=0.04).

CONCLUSION

Although individually there was no association between TNFRII T587G or TNF-alpha G238A polymorphisms and ALD, this study suggests that the presence of both polymorphisms may enhance the susceptibility for ALD. TNF-alpha G238A may increase TNF-alpha production, which when associated with TNFRII T587G, can further exacerbate TNF-alpha response leading to a greater risk of ALD.

Elevated soluble tumor necrosis factor receptor 75 concentrations identify patients with liver cirrhosis at risk of death

BACKGROUND & AIMS

Elevated levels of the soluble 75-kd receptor for tumor necrosis factor-alpha (sTNF-R 75) are better predictors of mortality in cirrhosis than the Child-Turcotte-Pugh (CTP) score. Thus, we compared sTNF-R 75 with the Model for End-Stage Liver Disease (MELD), CTP, and the sTNF-R 75/55 ratio.

METHODS

Ninety-two patients with liver cirrhosis (mean age, 55 years; range, 19-76 years; male, 66%; CTP stage C, 41%) were included in our prospective single-center survival study. The study setting was a tertiary care university clinic. Soluble TNF-R levels were determined, and the primary end point was death.

RESULTS

During > or =730 days, 44 patients died. Multivariate Cox regression analysis revealed sTNF-R 75 (> or =14 ng/mL) as an independent predictor of mortality (hazard ratio, 2.53; P = .006). By receiver operating characteristic, MELD and sTNF-R 75 were more accurate in predicting 6-, 15-, and 24-month mortality than CTP and sTNF-R 75/55. This was significant for 6 months (MELD, 0.78; sTNF-R 75, 0.75 vs sTNF-R 75/55, 0.60). In patients with high MELD scores (> or =15), survival was further reduced if sTNF-R 75 values were elevated (P = .035).

CONCLUSIONS

Elevated sTNF-R 75 levels independently predicted mortality and improved MELD on the basis of evaluation of prognosis, especially in patients with high MELD scores. Thus, sTNF-R 75 levels might be a useful cytokine-based prognostic marker in patients with liver cirrhosis.

High dose lycopene supplementation increases hepatic cytochrome P4502E1 protein and inflammation in alcohol-fed rats

Recent in vitro evidence suggests that the antioxidant lycopene can prevent alcohol-induced oxidative stress and inflammation. However, knowledge of possible interactions in vivo between escalating doses of lycopene and chronic alcohol ingestion are lacking. In this study, we investigated potential interactions between alcohol ingestion and lycopene supplementation and their effect on hepatic lycopene concentration, cytochrome P4502E1 (CYP2E1) induction, and inflammation. Fischer 344 rats (6 groups, n = 10 per group) were fed either a liquid ethanol Lieber-DeCarli diet or a control diet (isocaloric maltodextrin substituted for ethanol) with or without lycopene supplementation at 2 doses (1.1 or 3.3 mg x kg body weight(-1) x d(-1)) for 11 wk. Plasma and hepatic concentrations of lycopene isomers were assessed by HPLC analysis. We examined expressions of hepatic CYP2E1 and tumor necrosis factor-alpha (TNFalpha) and the incidence of hepatic inflammatory foci. Both plasma and hepatic lycopene concentrations were greater in alcohol-fed rats than in control rats supplemented with identical doses of lycopene. In contrast, alcohol-fed rats had a lower percentage of lycopene cis isomers in the plasma and the liver compared with control rats fed the same dose of lycopene. Notably, lycopene supplementation at the higher dose significantly induced hepatic CYP2E1 protein, TNFalpha mRNA, and the incidence of inflammatory foci in the alcohol-fed rats but not in the control rats. These data indicate an interaction between chronic alcohol ingestion and lycopene supplementation and suggest a need for caution among individuals consuming high amounts of both alcohol and lycopene.

Tumour necrosis factor (TNF-alpha) alpha converting enzyme and soluble TNF-alpha receptor type 1 in psoriasis patients in relation to the chronic alcohol consumption

BACKGROUND

Tumour necrosis factor alpha converting enzyme (TACE) is a major sheddase of TNF-alpha and its receptors, essential for the generation of soluble, mature molecules. The regulation of the TACE activity by ethanol in vitro has been suggested recently. The alcohol abuse is a frequent problem among psoriasis patients. The aim of the study was to analyse the relationship between long-term alcohol consumption and the concentration of TACE in peripheral blood mononuclear cells (PBMC) and its substrate--soluble TNF-alpha receptor type 1 (sTNF-R1) in plasma in psoriasis patients.

METHODS

The study has been conducted among 44 patients (aged 30-59 years) with early-onset, plaque-type psoriasis. Thirty-eight patients (aged 29-61 years) with other than psoriasis chronic dermatologic disorders were controls. The data on alcohol consumption during previous 10 years were obtained with a structured questionnaire. The severity of the disease was assessed using Psoriasis Area and Severity Index (PASI), and concentrations of TACE in PBMC lysate and sTNF-R1 in plasma was assessed with a quantitative sandwich enzyme immunoassay technique.

RESULTS

The TACE concentration correlated to that of sTNF-R1 (R = 0.52 in psoriasis patients and R = 0.56 in controls, P < 0.05). The concentrations of TACE were 2.62 +/- 0.32 ng/mL in patients and 1.29 +/- 0.25 ng/mL in controls (P < 0.05), and corresponding sTNF-R1 concentrations were 2.54 +/- 0.27 ng/mL and 1.79 +/- 0.14 ng/mL (P < 0.05), respectively. The concentrations of TACE and sTNF-R1 in patients correlated to the intensity of alcohol consumption (R = 0.56, and R = 0.52, P < 0.05, respectively) and were the highest in excessive drinking psoriasis patients (2.94 +/- 0.34 and 2.67 +/- 0.13 ng/mL).

CONCLUSION

The alcohol abuse may contribute to the increase of TACE expression in PBMC and also to the elevated plasma sTNF-R1 concentration in psoriasis patients.

Production of inflammatory cytokines by peripheral blood monocytes in chronic alcoholism: relationship with ethanol intake and liver disease

BACKGROUND

Controversial results have been reported about the effects of alcoholism on the functionality of monocytes. In the present study we analyze the effects of chronic alcoholism on the intracellular production of inflammatory cytokines by peripheral blood (PB) monocytes.

METHODS

Spontaneous and in vitro-stimulated production of interleukin (IL) 1alpha (TNFalpha) by PB monocytes was analyzed at the single level by flow cytometry in chronic alcoholics without liver disease and active ethanol (EtOH) intake (AWLD group), as well as in patients with alcohol liver cirrhosis (ALC group), who were either actively drinking (ALCET group) or with alcohol withdrawal (ALCAW group).

RESULTS

A significantly increased spontaneous production of IL1beta, IL6, IL12, and TNFalpha was observed on PB monocytes among AWLD individuals. Conversely, circulating monocytes form ALCET patients showed an abnormally low spontaneous and stimulated production of inflammatory cytokines. No significant changes were observed in ALCAW group as regards production of IL1beta, IL6, IL12, and TNFalpha.

CONCLUSION

Our results show an altered pattern of production of inflammatory cytokines in PB monocytes from chronic alcoholic patients, the exact abnormalities observed depending on both the status of EtOH intake and the existence of alcoholic liver disease.

Expression of β2-integrin on leukocytes in liver cirrhosis

AIM: To analyze β2-integrin expression on blood leukocytes in liver cirrhosis.

METHODS: In 40 patients with liver cirrhosis and 20 healthy individuals, the evaluation of expression of CD11a (LFA-1α), CD11b (Mac-1α), CD11c (αX) and CD49d (VLA-4α) on peripheral blood leukocytes was performed using flow cytometry. The analysis was carried out in groups of patients divided into B and C according to Child-Pugh’s classification.

RESULTS: An increased CD11a, CD11b, CD11c and CD49d integrin expression was observed on peripheral blood leukocytes in liver cirrhosis. The integrin levels were elevated as the advancement of liver failure progressed. The highest expression of integrins occurred predominantly on monocytes. A slight expression of VLA-4 was found on lymphocytes and granulocytes and it increased together with liver failure. A positive correlation was noted between median intensity of fluorescence (MIF) expression on polymorphonuclear cells of CD11a and CD11c and CD49d (r = 0.42, P < 0.01; r = 053, P < 0.01, respectively) in liver cirrhosis stage C. However, no correlation was observed between integrin expression on leukocytes. The concentrations of sICAM-1, sVCAM-1, and TNFα, were significantly elevated in liver cirrhosis.

CONCLUSION: β2-integrin expression on leukocytes increases in liver cirrhosis decompensated as the stage of liver failure increases, which is a result of permanent activation of leukocytes circulating through the inflamed liver environment. β2-integrin expression on circulating leukocytes can intensify liver cirrhosis.

Patients with acute on chronic liver failure display "sepsis-like" immune paralysis

BACKGROUND/AIMS

Cellular immune depression is linked to high mortality in sepsis, but has yet to be systematically analysed in liver cirrhosis. The aim of the present study was to directly compare functional immune parameters in patients with acute on chronic liver failure (ACLF), severe sepsis, and non-decompensated cirrhosis.

METHODS

Patients with ACLF (n=27) were investigated at admission to a medical ICU. Patients with stable liver cirrhosis (n=24) and severe sepsis (n=31) served as control groups. In all subjects, serum levels of IL-6 and IL-10, ex vivo production of TNF-alpha in a whole blood assay, and monocyte surface HLA-DR expression were determined.

RESULTS

In patients with ACLF or sepsis, ex vivo TNF-alpha production and HLA-DR expression were severely decreased compared to subjects with stable cirrhosis (both P<0.001). Contrary, IL-6 levels were highest in septic patients, followed by subjects with ACLF and cirrhotic patients (both P<0.05). Immune dysfunction in ACLF was independent of aetiology of liver cirrhosis and associated with high mortality.

CONCLUSIONS

Patients with ACLF and severe sepsis show a similar degree of cellular immune depression. The reduced cellular immune function in subjects with ACLF might contribute to the increased infectious morbidity of these patients and provide a rational basis for prevention strategies.

Chronic ethanol enhances ectodomain shedding in T cells and monocytes

BACKGROUND

Chronic ethanol (EtOH) has been shown to augment tumor necrosis factor (TNF)-alpha production, and this has been associated with EtOH-induced liver injury. We have recently described a chronic in vitro cell culture model where chronic ethanol exposure results in significantly augmented TNF production in Mono Mac 6 cells, a human monocytic cell line. This enhanced TNF production was redox regulated and associated with increased levels of TNF messenger RNA (mRNA) as well as increased processing of TNF by TNF converting enzyme (TACE), the enzymatic activity of which is regulated by the cellular redox state. We hypothesized that chronic ethanol through oxidative stress activates TACE-mediated ectodomain shedding of the preformed substrates p75 and p55 TNF receptors in Mono Mac 6 cells and L-selectin in Jurkat T cells.

METHODS

Mono Mac 6 or Jurkat T cells were treated with EtOH (0, 50, or 100 mM) for 4 to 6 days. Shedding of p75 and p55 TNF receptors (Mono Mac 6 cells) or L-selectin (Jurkat T cells) was induced by stimulation with lipopolysaccharide and phorbol myristate acetate for Mono Mac 6 cells and PMA alone for Jurkat T cells. Shedding was assessed by enzyme-linked immunosorbent assay for shed molecules in the cell supernatant as well as the cell-associated proteins recovered from cell pellets. Steady-state mRNA levels for p75 TNF receptor and L-selectin were determined by ribonuclease protection assay. Cell surface L-selectin and TACE were measured by flow cytometry, and cell associated p55 and p75 TNF receptors were measured by enzyme-linked immunosorbent assay.

RESULTS

Chronic EtOH exposure for 6 days resulted in a significant dose-dependent increase in shedding of p75 and p55 TNF receptors from Mono Mac 6 cells and L-selectin from Jurkat T-cells. The enhanced shedding was correlated with an alcohol-induced increase in mRNA levels and cell surface protein levels for these TACE substrates. Although chronic EtOH exposure increased the total amount of p75 and p55 TNF receptor and L-selectin shed into the media, the efficiency of shedding was suppressed by EtOH. In the case of Mono Mac 6 cells, the EtOH exposure increased superoxide production. Inhibition of nicotinamide adenine dinucleotide phosphate (reduced form) oxidase and hydrogen peroxide partially prevented the increased production of p75 TNF receptor in these cells.

CONCLUSIONS

These results suggest that chronic EtOH up-regulates p75 and p55 TNF receptors on monocytes and L-selectin on T-cells. However, the TACE-mediated shedding efficiency of these substrates may be inhibited in the presence of EtOH. These results may have implications in monocyte signaling and T-cell trafficking, which may, in part, contribute to immune dysregulation associated with chronic ethanol.

Implication of inflammation-related cytokines in the natural history of liver cirrhosis

BACKGROUND/AIMS

Increased serum concentrations of pro-inflammatory cytokines have been detected in patients with liver cirrhosis. However, their role in the natural history of cirrhosis and portal hypertension, in the absence of infection, and the prognostic significance of inflammation-related cytokines have not been reported. Our objective was the analysis of the prognostic value of inflammation-related cytokines in cirrhotic patients.

PATIENTS AND METHODS

Serum concentrations of tumor necrosis factor (TNF-alpha) and its soluble receptors I and II and interleukin 6 (IL-6), as well as mean blood pressure, plasma renin activity, aldosterone, vasopressin and norepinephrine concentrations were determined in 72 cirrhotic patients (Child-Pugh score: A 50%, B 33.3%, C 16.7%), without any evidence of infection, and in 25 healthy controls. Patients were followed up for a median of 35.9 (range 6-60) months.

RESULTS

Increased concentrations of soluble TNF receptors were detected in cirrhotic patients when compared with healthy controls. TNF receptors and IL-6 concentrations were both significantly more elevated in advanced phases of cirrhosis (Child-Pugh score C vs B and vs A). Sixteen patients died as a related consequence of liver cirrhosis. Multivariant analysis demonstrated that Child-Pugh score, mean blood pressure and serum levels of TNF receptor I were associated with mortality.

CONCLUSIONS

In addition to the classic factors implicated in mortality (Child-Pugh score and hemodynamic parameters), alterations in inflammation-related components are of prognostic significance in cirrhotic patients.

[Soluble interleukin-2 and tumor necrosis factor receptor in liver cirrhosis. Relationship with clinical severity and prognosis]

BACKGROUND AND OBJECTIVE

The mechanism responsible for the beginning and progression of hepatic injury in liver cirrhosis of viral and alcoholic etiology are unknown currently. However, there are abnormalities in the immune system which may be implied in the pathogenesis.

PATIENTS AND METHOD

The concentrations of the soluble receptor of tumor necrosis factor (sTNF-R55) and the soluble receptor of interleukin-2 (sIL-2R) in 49 cirrhotic patients were determined by enzyme-linked inmunoassay. Patients were grouped according to the etiology (33 alcoholic and 16 viral) and prognosis (Child-Pugh classification) and they were compared with the values obtained in 26 healthy non-drinkers who made up the control group.

RESULTS

The concentrations of sTNF-R55 and sIL-2R were significantly higher in both groups of patients when compared with controls. We found significant differences in sTNF-R55 concentrations in viral and alcoholic but not in sIL-2R concentrations. There was a positive correlation between the concentrations of both receptors and the degrees of Child-Pugh classification, as well as with albumin, total bilirubin and alkaline phosphatase (all of them parameters related to the severity and prognosis of liver cirrhosis).

CONCLUSIONS

The serum concentrations of soluble receptors of tumor necrosis factor and interleukin-2 correlate with the prognosis of liver cirrhosis independently of its etiology. This fact may reflect the stimulation of T lymphocytes, monocytes and macrophages, in liver cirrhosis.

Tumour necrosis factor-alpha expression by activated monocytes and altered T-cell homeostasis in ascitic alcoholic cirrhosis: amelioration with norfloxacin

BACKGROUND/AIMS

To investigate the distribution and activation state of circulating monocytes and T-cell subsets, their contribution to tumour necrosis factor-alpha (TNFalpha) production, and their potential relationship with bacterial products of enteric origin in alcoholic cirrhosis.

METHODS

Peripheral blood monocytes and T-lymphocytes from 60 cirrhotic patients and 24 controls were characterized by four-color flow-cytometry after labelling of differentiation antigens and cytokines, before and after a 4-week course of norfloxacin or placebo.

RESULTS

Monocytes from ascitic patients showed increased number, enhanced CD80 and HLA-DR surface levels, and spontaneous intracytoplasmic TNFalpha expression, when compared to non-ascitic patients and controls. Blood TNFalpha levels directly correlated with the amount of TNFalpha expressed by monocytes. In ascitic patients, there was a collapse of virgin CD4(+) and CD8(+) T-cell subsets; and, an expansion of activated CD4(+) T-cells. The above abnormalities were mainly restricted to ascitic patients with high serum levels of lypolysaccharide-binding-protein. Norfloxacin normalized the number of monocytes, reduced their activated phenotype and ability to produce TNFalpha and improved the abnormal T-cell homeostasis.

CONCLUSIONS

In ascitic cirrhosis with high lipolysaccharide-binding-protein, monocytes are spontaneously activated to produce TNFalpha and are major contributors to the elevated serum TNFalpha. The T-cell compartment is profoundly depleted. Enteric bacterial products play a relevant role in these immune cellular abnormalities.

A pilot study to investigate the use of oxpentifylline (pentoxifylline) and thalidomide in portal hypertension secondary to alcoholic cirrhosis

BACKGROUND

Tumour necrosis factor-alpha is thought to be important in the pathogenesis of portal hypertension. Oxpentifylline (pentoxifylline) and thalidomide inhibit endotoxin-induced tumour necrosis factor-alpha production in vitro.

AIMS

To assess the toxicity of oxpentifylline (pentoxifylline) and thalidomide in cirrhosis and their effect on the hepatic venous pressure gradient and tumour necrosis factor-alpha production.

METHODS

In an open-label pilot study, 20 abstinent patients with stable alcoholic cirrhosis and oesophageal varices were recruited; 12 patients completed haemodynamic measurements before and after treatment with oxpentifylline (pentoxifylline) 1800 mg (n=6) or thalidomide 200 mg (n=6) daily for 2 weeks. Tumour necrosis factor-alpha production was assessed in ex vivo monocyte cultures stimulated with endotoxin.

RESULTS

Thalidomide reduced the hepatic venous pressure gradient from 19.7 mmHg (9.3-23.5 mmHg) to 12.2 mmHg (4.7-19.5 mmHg) (P=0.03) without reducing the hepatic blood flow or altering systemic haemodynamic parameters. Thalidomide reduced ex vivo tumour necrosis factor-alpha production by approximately 50%. Oxpentifylline (pentoxifylline) had no significant effect on any of the parameters measured. Side-effects led to dose reduction or treatment withdrawal in 40% of patients.

CONCLUSION

Thalidomide, but not oxpentifylline (pentoxifylline), reduces the hepatic venous pressure gradient in stable alcoholic cirrhotics, an effect that may be mediated by the inhibition of tumour necrosis factor-alpha production. The role of tumour necrosis factor-alpha inhibitory drugs in the therapy of portal hypertension should be investigated in a randomized controlled trial.

Hepatitis B core antigen is a potent inductor of interleukin-18 in peripheral blood mononuclear cells of healthy controls and patients with hepatitis B infection

Clearance of hepatitis B virus infection (HBV) infection implies a polyclonal vigorous T-helper 1 (Th1) and cytotoxic T-lymphocyte (CTL) response. Interleukin-18 (IL-18), a monokine that shares functional abilities with IL-12, is a potent inductor of interferon-gamma (IFN-gamma) by Th1 and natural killer (NK) cells. However, the role and regulation in HBV infection of IFN-gamma have not been defined. This study therefore sought to determine hepatitis B core antigen (HBcAg)-mediated regulation of IL-18 production in peripheral blood mononuclear cells (PBMCs) from healthy controls (HC) and patients with chronic hepatitis B (CHB) or acute hepatitis B (AHB); 31 HC, 27 patients with CHB and 8 patients with AHB infection were included in the study. HBcAg-mediated induction of IL-18 was determined by quantitative reverse transcription-polymerase chain reaction (RT-PCR) and specific enzyme-linked immunosorbent assay (ELISA). HBcAg induced IL-18 gene transcription and dose-dependent secretion of mature IL-18 protein in HC, CHB, and AHB. HBcAg-dependent IL-18 levels were abrogated by inhibition of Caspase-1, but not by blockade of CD40-CD154 interaction. Serum levels of IFN-gamma correlated inversely with viremia in patients with CHB (rho = - 0.54, P < 0.05), but not with serum levels of IL-12 or IL-18. Interestingly, in PBMCs of HBeAg-negative patients, HBcAg induced significantly higher amounts of IL-18 than in those of HBeAg-positive patients. A variant, lacking the histone-like arginine-rich domain, did not induce IL-18 in either HC or CHB in vitro. Taken together, these results indicate that HBcAg induces IL-18 secretion by induction of Caspase-1. Differential regulation in HBeAg-negative and positive patients suggests an important role of IL-18 in CHB infection.

Differential expression of toll-like receptors 2 and 4 in patients with liver cirrhosis

OBJECTIVE

Toll-like receptors (TLR) 2 and 4 were shown recently to mediate lipopolysaccharide (LPS)/endotoxin effects in vivo. Absence of clinical features, such as fever and leucocytosis, frequent infections, and up-regulation of anti-inflammatory cytokines suggest systemic differential regulation of LPS effects in patients with chronic endotoxinaemia due to liver cirrhosis.

DESIGN

Regulation of TLR2 and TLR4 represents a possible pathway to control LPS-induced immune responses in liver cirrhosis.

METHODS

We compared the expression of TLR2 and TLR4 in peripheral blood mononuclear cells (PBMC) (n = 28) and in liver biopsies (n = 20) of controls and of patients with liver cirrhosis by applying the reverse transcriptase polymerase chain reaction technique. The data were correlated to serum levels of LPS and CD14.

RESULTS

Expression of TLR2 was up-regulated (P < 0.01 to P < 0.05) in the PBMC of patients with high serum endotoxin levels, while TLR4 expression in patients at Child-Pugh stage A was down-regulated, irrespective of the origin (alcoholic or viral) of cirrhosis. A strong and significant correlation between expression of TLR2 and serum LPS (r = 0.638, P < 0.01) and soluble CD14 (r = 0.550, P < 0.05) was observed. Intrahepatic expression of TLR2/4 was not altered significantly in patients with liver cirrhosis.

CONCLUSION

Our data indicate LPS-driven regulation of TLR2/4 in patients with liver cirrhosis, suggesting involvement in mechanisms of systemic LPS hyporesponsiveness.

Single nucleotide polymorphisms and microsatellite alleles of tumor necrosis factor alpha and interleukin-10 genes and the risk of advanced chronic alcoholic liver disease

BACKGROUND

Only a minority of ethanol abusers develop advanced chronic alcoholic liver disease (CALD). In CALD there is a imbalance between TNF alpha and IL-10, which may be modulated by several polymorphisms at both genetic loci. Our aim has been to elucidate the possible relation between these polymorphisms and the risk of CALD.

PATIENTS AND METHODS

147 patients with advanced CALD and 355 healthy controls (all white Spaniards) were included. TNF alpha biallelic single nucleotide polymorphisms (SNP) at positions -238, -308, and -376 and IL-10 biallelic SNP at positions -597, - 824, and - 1087 were investigated by polymerase chain reaction (PCR) amplification and dot blot hybridization. Moreover, polymorphic microsatellites TNFa, TNFb, IL-10.R and IL-10.G were investigated in a multiplex PCR and alleles were estimated in an automatic sequencer.

RESULTS

No differences were found in the distribution of any of the studied polymorphisms, except by an excess of the haplotype formed by the allele 11 of the microsatellite IL-10.G and the GCC arrangement of the SNPs at the promoter of IL-10 gene in patients (15.7 vs. 8.24%, odds ratio: 2.08, 95% C.I. = 1.31-3.31).

CONCLUSIONS

The studied polymorphisms at TNF alpha and IL-10 genetic loci are not clearly related to the risk of CALD. The excess of G11-GCC haplotype found in CALD patients needs independent confirmation.

Monocyte activation in alcoholic liver disease

Activated monocytes and macrophages have been postulated to play an important role in the pathogenesis of alcoholic liver disease (ALD). Monocyte activation can be documented by measurement of neopterin, adhesion cell molecules, and certain proinflammatory cytokines and chemokines. We first became interested in the role of monocytes and monocyte-derived cytokines in ALD in relation to altered zinc metabolism that occurs regularly in ALD. Patients with ALD have hypozincemia, which responds poorly to oral zinc supplementation. We have shown that in ALD monocytes make a low-molecular-weight substance that, when injected into rabbits, causes prominent hypozincemia. Subsequently, multiple cytokines [especially tumor necrosis factor (TNF) and interleukin (IL)-8] have been shown to be overproduced by monocytes in ALD. We initially showed that monocytes in ALD spontaneously produce TNF and overproduce TNF in response to a lipopolysaccharide (LPS) stimulus, and this could be attenuated by antioxidants in vitro and in vivo. Alterations in the endotoxin-binding protein LPS-binding protein, in CD14, and in the endotoxin receptor Toll-like receptor 4 all may play roles in enhanced proinflammatory cytokine signaling in ALD. Moreover, several groups have documented increased TNF receptor density in monocytes in ALD. Inadequate negative regulation of TNF occurs at multiple levels in ALD. This includes decreased monocyte production of the important antiinflammatory cytokine IL-10 and blunted response to the antiinflammatory properties of adenosine. Finally, generation of reactive oxygen species (which occurs during alcohol metabolism) and products of lipid peroxidation induce production of cytokines, such as TNF and IL-8. In conclusion, there are multiple overlapping potential mechanisms for enhanced proinflammatory cytokine production by monocytes in ALD. We postulate that activation of monocytes and macrophages with subsequent proinflammatory cytokine production plays an important role in certain metabolic complications of ALD and is a component of the liver injury of ALD.

Tumor necrosis factor soluble receptor p55 and lipid peroxidation in patients with acute alcoholic hepatitis

OBJECTIVES

In experimental models, liver injury induced by ethanol, cytotoxic activity of tumor necrosis factor (TNF) -alpha is principally mediated by TNF receptor p55 (TNFRp55). Among the various mechanisms underlying the toxic effects of TNF-alpha, overproduction of reactive oxygen species seems to play a key role in mediating TNF-alpha-induced cytotoxicity. The aim of this study was to evaluate, in patients with alcoholic liver disease, whether alcohol TNFRp55-mediated hepatotoxicity could account for lipid peroxidation expressed by significant increase in serum thiobarbituric reactive acid substances (TBARS) content, and could be amplified by decrease in blood total glutathione content and decrease in plasma antioxidant protective capacity.

METHODS

We studied 27 patients with histological alcoholic liver disease (five fibrosis, six acute alcoholic hepatitis (AAH) without cirrhosis, four cirrhosis without AAH, and 12 cirrhosis with AAH. TNFsRp55 and TNFsRp75 plasma levels were measured using ELISA assays. Plasma lipid peroxidation was evaluated by the content of TBARS. Total glutathione (tGSH) content in blood was determined by a kinetic assay. The sensitivity of erythrocytes to an oxidative stress and the plasma antioxidant protective capacity were simultaneously determined by a simple method.

RESULTS

In the 18 patients with mild or severe AAH, the plasma levels of TNFsRp55 were negatively correlated with tGSH and were positively correlated with TBARS, with total bilirubin and with discriminant function. tGSH was positively correlated with plasma selenium. The plasma levels of TNFsRp75 were positively correlated with TBARS and with total bilirubin. There was no significant correlation with the mean inhibitory 50% plasma volume or with the percentage of hemolyzed erythrocytes.

CONCLUSIONS

Our data support the notions that, in patients with AAH, TNFsRp55 probably mediates cytotoxicity of TNF-alpha, and that cytotoxic effect could be amplified by tGSH depletion in enhancing lipid peroxidation.

The role of tumor necrosis factor-alpha in liver toxicity, inflammation, and fibrosis induced by carbon tetrachloride

Hepatic expression of the proinflammatory cytokine tumor necrosis factor-alpha (TNFalpha) occurs in many acute and chronic liver diseases, as well as following exposure to hepatotoxic chemicals, and is believed to help influence both the damage and repair processes that occur following these insults by regulating additional mediators. We examined the role of TNFalpha in transgenic mice deficient in TNF receptors (TNFR) utilizing carbon tetrachloride (CCl(4)) as a model hepatotoxic agent that allowed for the evaluation of necrosis, inflammation, and fibrosis. Hepatocyte damage, as evident by local areas of liver necrosis and elevated levels of serum transaminase, occurred to a similar degree in wild-type and TNFR-deficient knockout (KO) mice following acute exposure to CCl(4). In contrast, the inflammatory response, manifested as an inflammatory cell influx, as well as induction of chemokines and adhesion molecules that occurred in wild-type mice following treatment with CCl(4), was not as evident in TNFR-KO mice. This response was associated primarily with type-1 (TNFR1) rather than type-2 (TNFR2) receptor responses. Liver fibrosis resulting from chronic CCl(4) exposure was also markedly dependent upon TNFalpha as demonstrated by almost a complete histological absence of fibrosis in TNFR-deficient mice. This was further supported by marked reductions in procollagen and transforming growth factor beta synthesis in TNFR-deficient mice. Taken together, these results indicate that TNFalpha is responsible for regulating products that induce inflammation and fibrosis but not direct hepatocyte damage in CCl(4)-induced hepatotoxicity.

Serum cytokine levels in alcohol-related liver cirrhosis

Chronic alcoholism complicated by alcoholic liver disease is characterized by activation of the inflammatory response system. To evaluate the role of cytokines in the progress of alcoholic cirrhosis, we assessed serum level of the proinflammatory cytokines tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6, and IL-8 and the antiinflammatory cytokines IL-2, IL-10, and transforming growth factor (TGF)-beta in patients with compensated and decompensated alcoholic liver cirrhosis. Compensated alcoholic cirrhosis was characterized by increased IL-6 (6.3+/-2.9 vs. HP 2.2+/-1.4 pg/ml in controls) and decreased IL-10 (HP 4.1+/-3.5 vs. 6.4+/-5.4 pg/ml in controls). TNF-alpha, IL-8, and TGF-beta1 levels were comparable to those found in controls. In sera of patients with decompensated alcoholic liver cirrhosis, besides increased IL-6 (11.2+/-7.7 pg/ml), increased concentrations of TNF-alpha (25.1+/-4.5 vs. 9.1+/-7.0 pg/ml in controls) and IL-8 (171.7+/-294.0 vs. 2.7+/-2.9 pg/ml in controls) were also detected. TGF-beta1 and IL-10 levels were similar to those found in controls. These results strongly indicate that a significant derangement of the balance between proinflammatory and antiinflammatory signals is characteristic of compensated and especially of decompensated alcoholic cirrhosis.