RESUMO
BACKGROUND: Autoimmune hepatitis (AIH) is a rare chronic liver disease. Impaired health-related quality of life (HRQL) contributes to the overall disease burden. At current, only limited data related to the impact of treatment response on HRQL are available. OBJECTIVE: The aim of the study was to determine the impact of biochemical remission on HRQL. METHODS: Patients with AIH were prospectively enrolled between July 2018 and June 2019. A liver disease-specific tool, the chronic liver disease questionnaire (CLDQ) and the generic EQ-5D-5L were used to quantify HRQL. Treatment response was assessed biochemically by measurement of immunoglobulin G, ALT and AST. The cohort was divided into two groups according to their biochemical remission status in either complete vs. incomplete remission. Clinical as well as laboratory parameters and comorbidities were analysed using univariable and multivariable analysis to identify predictors of poor HRQL. RESULTS: A total of 116 AIH patients were included (median age: 55; 77.6% female), of which 9.5% had liver cirrhosis. In this cohort, 38 (38.4%) showed a complete and 61 (61.6%) an incomplete biochemical remission at study entry. The HRQL was significantly higher in patients with a complete as compared to an incomplete biochemical remission (CLDQ overall score: 5.66 ± 1.15 vs. 5.10 ± 1.35; p = 0.03). In contrast, the generic EQ-5D-5L UI-value was not different between the groups. Multivariable analysis identified AST (p = 0.02) and an incomplete biochemical remission (p = 0.04) as independent predictors of reduced HRQL (CLDQ total value). CONCLUSION: Patients with a complete biochemical remission had a significantly higher HRQL. Liver-related quality of life in patients living with AIH is dependent on the response to immunosuppressive treatment.
Assuntos
Hepatite Autoimune , Qualidade de Vida , Estudos de Coortes , Feminino , Hepatite Autoimune/tratamento farmacológico , Humanos , Cirrose Hepática , Masculino , Pessoa de Meia-Idade , Qualidade de Vida/psicologia , Inquéritos e QuestionáriosRESUMO
BACKGROUND: Primary biliary cholangitis (PBC) is a chronic, cholestatic liver disease that can lead to end-stage liver disease and impairs the quality of life. At current, most data come from few large cohorts. AIM: This cross-sectional study evaluated treatment response and symptom burden in patients with PBC in Germany to expand the available data. METHODS: A total of 140 PBC patients were prospectively enrolled at the outpatient liver clinic of the University Medical Center in Mainz starting in June 2016. Historic and current response rates of UDCA treatment were determined using published binary models. Symptom burden was assessed using the PBC-40 questionnaire. RESULTS: The primary treatment response ranged between 73 and 86% depending on the definition used. Importantly, this response rate was maintained over a median time of 5 years in follow-up. The highest symptom burden was observed for fatigue and emotional (2.4 ± 1; 2.3 ± 1.1 of 5), while pruritus (1.1 ± 1.1 of 5) had the lowest scores. IgG correlated with the PBC-40 domain social (r = 0.211, p = 0.032), while HDL inversely correlated with the symptom burden of pruritus (r = - 0.236; p = 0.018). CONCLUSION: In this tertiary care cohort, 75% of the patients showed biochemical response after 1 year according to the acknowledged Paris II criteria. Patients reported a significant symptom burden, and the domain fatigue of the PBC-40 was most prominently impaired.
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Colagogos e Coleréticos/uso terapêutico , Cirrose Hepática Biliar/diagnóstico , Cirrose Hepática Biliar/tratamento farmacológico , Avaliação de Sintomas , Ácido Ursodesoxicólico/uso terapêutico , Idoso , Estudos Transversais , Feminino , Alemanha , Nível de Saúde , Humanos , Cirrose Hepática Biliar/complicações , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Qualidade de Vida , Fatores de Tempo , Resultado do TratamentoRESUMO
GOALS: The aim of this study was to assess the long-term outcome of primary biliary cirrhosis (PBC) patients and to test the clinical value of various outcome models, such as the Mayo Risk Score (MRS), in a large single-center cohort in Germany. BACKGROUND: PBC is a chronic autoimmune liver disease with a female gender predominance and a peak incidence in the fifth decade of life. PBC is characterized by portal inflammation and immune-mediated destruction of intrahepatic bile ducts in liver histology and the presence of antimitochondrial antibodies in the serum of nearly 95% of patients. In 5% to 20% of patients an overlap syndrome with autoimmune hepatitis (AIH) is diagnosed. Ursodeoxycholic acid is widely accepted as the standard medical treatment. STUDY: A total of 204 patients with PBC or PBC/AIH were retrospectively analyzed with regard to their clinical, biochemical, serological, and histologic features. PBC was diagnosed on the basis of the American Association for the Study of Liver Diseases criteria. Specific PBC scores, such as the MRS, the European and the Yale model, as well as nonspecific scores such as the Child-Pugh, the Model for End-stage Liver Disease, and Aspartate Aminotransferase to Platelet Ratio Index score were analyzed for their utility to predict the clinical outcome of patients. RESULTS: One hundred eighty-four patients with PBC alone and 20 with primary biliary cirrhosis/autoimmune hepatitis overlap were followed up for an average of 7.0 (range, 0.5 to 33.2) years. Importantly, baseline values of serum bilirubin, alkaline phosphatase, immunoglobulin M (IgM) and IgG, as well as antimitochondrial antibodies titers did not allow in properly predicting patient's outcome. The MRS proved clinical applicability. Patients with an R-value <6 did not develop liver-related complications. The Aspartate Aminotransferase to Platelet Ratio Index score had a significant correlation with the histologic degree of liver fibrosis, with limited value of scores between 1.0 and 1.5. Patients with a Model for End-stage Liver Disease score ≥8 (n=17) had a significantly higher risk to undergo liver transplantation or liver-related death. Outcome was less favorable than predicted by the European model. All scores showed low positive predictive values, limiting their applicability in clinical practice. CONCLUSIONS: Herein, we demonstrate that clinical risk scores in PBC should be interpreted with care. The MRS proved to be helpful to predict a favorable outcome. Novel approaches to predict outcome are needed to identify patients who may benefit from alternative, intensified treatment regimens.
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Hepatite Autoimune/sangue , Hepatite Autoimune/patologia , Cirrose Hepática Biliar/sangue , Cirrose Hepática Biliar/patologia , Índice de Gravidade de Doença , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Fosfatase Alcalina/sangue , Aspartato Aminotransferases/sangue , Bilirrubina/sangue , Criança , Colagogos e Coleréticos/uso terapêutico , Feminino , Seguimentos , Hepatite Autoimune/complicações , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Cirrose Hepática Biliar/complicações , Cirrose Hepática Biliar/terapia , Transplante de Fígado , Masculino , Pessoa de Meia-Idade , Contagem de Plaquetas , Valor Preditivo dos Testes , Prognóstico , Estudos Retrospectivos , Ácido Ursodesoxicólico/uso terapêutico , Adulto JovemRESUMO
INTRODUCTION: Chronic Hepatitis C virus infection (HCV) is associated with extrahepatic manifestations and an increased prevalence in cardiovascular disease. New direct acting antivirals (DAA) have revolutionized HCV treatment with high rates of sustained virological response (SVR). Recently it was demonstrated, that SVR reduces morbidity and overall mortality more than can be solely explained by hepatic effects, suggesting that treatment with DAA also affects cardiovascular disease. The aim of this pilot study was to identify possible underlying mechanisms behind the HCV-associated cardiovascular mortality reported by others. METHODS AND RESULTS: 20 HCV patients (10 genotype GT1, 10 GT3) were treated with interferon (IFN)- and ribavirin (RBV)-free DAA regimens for 12â¯weeks (SVR12). Primary endpoint was an improvement in endothelial function (flow-mediated dilation, FMD) at SVR12 compared to baseline. Patient demographics, FMD, markers for endothelial function and inflammation, coagulation and oxidative stress were measured at baseline, end of treatment and SVR12. All patients achieved SVR12. There was a significant increase in FMD from 9.4⯱â¯5.2% at baseline to 11.9⯱â¯4.5% at SVR12 (pâ¯=â¯0.04). Concomitantly, there were significant reductions in levels of endothelium-derived adhesion molecules E-selectin, VCAM-1 and ICAM-1. While APRI values were also significantly lower, liver stiffness did not change significantly. There were no relevant changes in systemic inflammation, oxidative stress, insulin resistance or coagulation pathways. CONCLUSIONS: Successful DAA therapy was associated with improvements in endothelial function and a reduction of soluble adhesion molecules. Our findings indicate that HCV infection affects the endothelium and that DAA-treatment reverses these effects and enhances endothelial function.
Assuntos
Antivirais/administração & dosagem , Endotélio Vascular/efeitos dos fármacos , Hepatite C Crônica/tratamento farmacológico , Interferons , Ribavirina , Adulto , Estudos de Coortes , Quimioterapia Combinada , Endotélio Vascular/fisiologia , Endotélio Vascular/virologia , Feminino , Hepatite C Crônica/sangue , Hepatite C Crônica/diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Resultado do TratamentoRESUMO
Cholangiocarcinomas are usually fatal neoplasms originating from bile duct epithelia. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising agent for cancer therapy, including cholangiocarcinoma. However, many cholangiocarcinoma cells are resistant to TRAIL-mediated apoptosis. Thus, our aim was to examine the intracellular mechanisms responsible for TRAIL resistance in human cholangiocarcinoma cell lines. Three TRAIL-resistant human cholangiocarcinoma cell lines were identified. All of the cell lines expressed TRAIL receptor 1/death receptor 4 (TRAIL-R1/DR4) and TRAIL-R2/DR5. Expression of TRAIL decoy receptors and the antiapoptotic cellular FLICE-inhibitory protein (cFLIP) was inconsistent across the cell lines. Of the antiapoptotic Bcl-2 family of proteins profiled (Bcl-2, Bcl-x(L), and Mcl-1), Mcl-1 was uniquely overexpressed by the cell lines. When small-interfering-RNA (siRNA) technology was used to knock down expression of Bcl-2, Bcl-x(L), and Mcl-1, only the Mcl-1-siRNA sensitized the cells to TRAIL-mediated apoptosis. In a cell line stably transfected with Mcl-1-small-hairpin-RNA (Mcl-1-shRNA), Mcl-1 depletion sensitized cells to TRAIL-mediated apoptosis despite Bcl-2 expression. TRAIL-mediated apoptosis in the stably transfected cells was associated with mitochondrial depolarization, Bax activation, cytochrome c release from mitochondria, and caspase activation. Finally, flavopiridol, an anticancer drug that rapidly down-regulates Mcl-1, also sensitized cells to TRAIL cytotoxicity. In conclusion, these studies not only demonstrate that Mcl-1 mediates TRAIL resistance in cholangiocarcinoma cells by blocking the mitochondrial pathway of cell death but also identify two strategies for circumventing this resistance.
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Antineoplásicos/antagonistas & inibidores , Apoptose/efeitos dos fármacos , Colangiocarcinoma/tratamento farmacológico , Peptídeos e Proteínas de Sinalização Intracelular , Glicoproteínas de Membrana/antagonistas & inibidores , Proteínas de Neoplasias/fisiologia , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Antineoplásicos/farmacologia , Apoptose/fisiologia , Proteínas Reguladoras de Apoptose , Proteína Reguladora de Apoptosis Semelhante a CASP8 e FADD , Proteínas de Transporte/biossíntese , Linhagem Celular Tumoral , Colangiocarcinoma/genética , Colangiocarcinoma/metabolismo , Colangiocarcinoma/patologia , Regulação para Baixo , Resistencia a Medicamentos Antineoplásicos , Sinergismo Farmacológico , Flavonoides/farmacologia , Genes bcl-2/genética , Humanos , Glicoproteínas de Membrana/farmacologia , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/fisiologia , Proteína de Sequência 1 de Leucemia de Células Mieloides , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , Piperidinas/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/genética , RNA Interferente Pequeno/genética , Receptores do Fator de Necrose Tumoral/biossíntese , Ligante Indutor de Apoptose Relacionado a TNF , Fator de Necrose Tumoral alfa/farmacologia , Proteína bcl-XRESUMO
BACKGROUND: Patients with chronic liver disease often suffer from unspecific symptoms and report severe impairment in the quality of life. The underlying mechanisms are multifactorial and include disease-specific but also liver related causes. The current analysis evaluated the association of hepatocellular apoptosis in non-viral chronic liver disease and health-related quality of life (HRQL). Furthermore we examined factors, which influence patient's physical and mental well-being. METHODS: A total of 150 patients with non-infectious chronic liver disease were included between January 2014 and June 2015. The German version of the Chronic Liver Disease Questionnaire (CLDQ-D), a liver disease specific instrument to assess HRQL, was employed. Hepatocellular apoptosis was determined by measuring Cytokeratin 18 (CK18, M30 Apoptosense ELISA). RESULTS: Female gender (5.24 vs. 5.54, p = 0.04), diabetes mellitus type II (4.75 vs. 5.46, p<0.001) and daily drug intake (5.24 vs. 6.01, p = 0.003) were associated with a significant impairment in HRQL. HRQL was not significantly different between the examined liver diseases. Levels of CK18 were the highest in patients with NASH compared to all other disease entities (p<0.001). Interestingly, CK18 exhibited significant correlations with obesity (p<0.001) and hyperlipidemia (p<0.001). In patients with cirrhosis levels of CK18 correlated with the MELD score (r = 0.18, p = 0.03) and were significantly higher compared to patients without existing cirrhosis (265.5 U/l vs. 186.9U/l, p = 0.047). Additionally, CK18 showed a significant correlation with the presence and the degree of hepatic fibrosis (p = 0.003) and inflammation (p<0.001) in liver histology. Finally, there was a small negative association between CLDQ and CK18 (r = -0.16, p = 0.048). CONCLUSION: Different parameters are influencing HRQL and CK18 levels in chronic non-viral liver disease and the amount of hepatocellular apoptosis correlates with the impairment in HRQL in chronic non-viral liver diseases. These findings support the role of liver-protective therapies for the improvement of the quality of life in chronic liver disease.
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Apoptose , Queratina-18/biossíntese , Cirrose Hepática/metabolismo , Fígado/metabolismo , Qualidade de Vida , Adulto , Idoso , Doença Crônica , Feminino , Humanos , Fígado/patologia , Cirrose Hepática/patologia , Masculino , Pessoa de Meia-IdadeRESUMO
BACKGROUND: In chronic genotype 1 hepatitis C, telaprevir or boceprevir plus peginterferon and ribavirin have become the new standard of care. Aim of this study was to identify factors contributing to the decision whether to defer or treat with the current triple regimens. METHODS: Prospective assessment of eight parameters on 0-4-point scales by the attending physician at a German tertiary referral centre between 1st September 2011 and 31st December 2012. RESULTS: 307 patients were evaluated at least once by one of the 11 hepatologists involved; 267 patients were considered, but only 163 were recommended to receive triple therapy. Multivariate regression analysis revealed that a higher degree of fibrosis was most strongly associated with a recommendation for treatment (OR 2.69), followed by the patients' demand (OR 2.27), presumed efficacy (OR 1.62), and tolerability (OR 1.58). A high risk of decompensation was associated with the decision to defer (OR 0.39). Speed of progression, compliance, extrahepatic manifestation, gender and age were not significantly related to the recommendation. Treatment was finally started in 101 patients (32.9%). CONCLUSION: In chronic genotype 1 hepatitis C, advanced fibrosis and patients' preference are the main rationales to choose treatment rather than deferral in a real-life setting.
Assuntos
Antivirais/uso terapêutico , Tomada de Decisões , Hepatite C Crônica/tratamento farmacológico , Interferon-alfa/uso terapêutico , Oligopeptídeos/uso terapêutico , Prolina/análogos & derivados , Ribavirina/uso terapêutico , Adulto , Idoso , Estudos de Coortes , Progressão da Doença , Portadores de Fármacos/uso terapêutico , Descoberta de Drogas , Quimioterapia Combinada , Feminino , Hepacivirus/genética , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Preferência do Paciente , Polietilenoglicóis/uso terapêutico , Prolina/uso terapêutico , Estudos Prospectivos , Índice de Gravidade de Doença , Fatores de Tempo , Conduta ExpectanteRESUMO
BACKGROUND: Nucleos(t)ides effectively halt disease progression in hepatitis B but require long-term medication. OBJECTIVES: To determine whether add-on of peg-IFN to an ongoing nucleos(t)ide therapy accelerates decline of HBsAg and induces seroconversion. STUDY DESIGN: We observed HBsAg kinetics in 12 patients on a stable oral therapy with undetectable HBV-DNA who additionally received peg-IFN-alfa 2a as an individualized therapy. 3 patients were HBeAg positive. Mean baseline HBsAg was 4695 (range 16-15,120)IU/ml. RESULTS: A continuous decline of HBsAg was observed in 2 patients. The slope, respectively, became detectable at week 8 or 16. HBsAg had dropped by 2.90log(10) or 4.25log(10) fold at week 48, and anti-HBs appeared at week 40 or 32. Patient A - HBe-positive, genotype A, F3 fibrosis - had been HBV-DNA negative for 10 months receiving entecavir plus tenofovir. Previous therapy with peg-IFN had been unsuccessful, but now the patient experienced HBeAg seroconversion at week 24. Patient B - HBeAg negative, genotype D, cirrhosis - had a low initial HBsAg level of 16U/l. Receiving entecavir, his HBV-DNA had previously been non-detectable for 27 months. In the remaining 10 patients HBsAg declined only by a mean of 0.09log(10) (range 0.01-0.25log(10)) after 8-24 (mean 16.4) weeks, and therefore, peg-IFN was stopped. No unexpected side effects were observed. DISCUSSION: We observed that the add-on of peg-IFN induced HBsAg seroconversion in 2 out of 12 patients. Response rates may have been higher with prolongation of therapy. The add-on concept merits to be evaluated in a clinical trial.
Assuntos
Antivirais/administração & dosagem , Antígenos de Superfície da Hepatite B/sangue , Hepatite B Crônica/tratamento farmacológico , Interferon-alfa/administração & dosagem , Polietilenoglicóis/administração & dosagem , Adulto , Quimioterapia Combinada/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas Recombinantes/administração & dosagem , Resultado do TratamentoRESUMO
Bile acids up-regulate death receptor 5 (DR5)/TRAIL-receptor 2 (TRAIL-R2) expression thereby sensitizing hepatocytes to TRAIL-mediated apoptosis. However, the precise mechanism by which bile acids enhance DR5/TRAIL-R2 expression is unknown. Although several bile acids enhanced DR5/TRAIL-R2 expression, deoxycholic acid (DCA) was the most potent. DCA stimulated JNK activation and the JNK inhibitor SP600125 blocked DCA-induced DR5/TRAIL-R2 mRNA and protein expression. Reporter gene analysis identified a 5'-flanking region containing two Sp1 binding sites within the DR5/TRAIL-R2 promoter as bile acid responsive. Sp1 binding to one of the two sites was enhanced by DCA treatment as evaluated by electrophoretic mobility shift assays and chromatin immunoprecipitation studies. JNK inhibition with SP600125 also blocked binding of Sp1 to the DR5/TRAIL-R2 promoter. Finally, point mutations of the Sp1 binding site attenuated promoter activity. In conclusion, Sp1 is a bile acid-responsive transcription factor that mediates DR5/TRAIL-R2 gene expression downstream of JNK.
Assuntos
Ácidos e Sais Biliares/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Receptores do Fator de Necrose Tumoral/genética , Fator de Transcrição Sp1/metabolismo , Antracenos , Sequência de Bases , Sítios de Ligação , Carcinoma Hepatocelular , Sequência Consenso , Primers do DNA , Ácido Desoxicólico/farmacologia , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Humanos , Neoplasias Hepáticas , Reação em Cadeia da Polimerase/métodos , Regiões Promotoras Genéticas/genética , Receptores do Ligante Indutor de Apoptose Relacionado a TNF , Transfecção , Células Tumorais CultivadasRESUMO
In cholestasis, toxic bile acids accumulate within the liver inducing hepatocyte apoptosis, which exacerbates liver injury. Although bile acids activate both death receptors and mitogen-activated kinase (MAPK) pathways, the mechanistic link between death receptor signaling and MAPK activation in bile acid apoptosis remains unclear. The aim of this study was to ascertain if MAPKs contribute to bile acid cytotoxicity. Although deoxycholate induced apoptosis and activated all three classic mediators of the MAPK pathways including JNK 1/2, p38, and p42/44, only p38 MAPK inhibition attenuated apoptosis. Suppressing FADD expression with siRNA or employing a caspase inhibitor, zVAD-fmk, did not block p38 MAPK activation suggesting its activation was not death receptor-dependent. Unexpectedly, expression of cFLIP-L in a stably transfected cell line blocked apoptosis and p38 MAPK phosphorylation. Based on these data we postulated a direct effect of cFLIP on p38 MAPK activation. The nonphosphorylated but not the phosphorylated/active form of p38 MAPK co-immunoprecipitated with cFLIP-L. In reverse immunoprecipitation experiments, cFLIP-L long but not cFLIP-S co-immunoprecipitate with p38 MAPK. In conclusion, these data suggest that cFLIP-L exerts its anti-apoptotic activity, in part, by inhibiting p38 MAPK activation, an additional anti-apoptotic effect for this protein.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Apoptose/fisiologia , Ácidos e Sais Biliares/metabolismo , Proteínas de Transporte/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Apoptose/efeitos dos fármacos , Proteína Reguladora de Apoptosis Semelhante a CASP8 e FADD , Proteínas de Transporte/genética , Caspases/metabolismo , Linhagem Celular , Ácido Desoxicólico/metabolismo , Ácido Desoxicólico/farmacologia , Ativação Enzimática , Proteína de Domínio de Morte Associada a Fas , Humanos , Fosforilação , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Transfecção , Proteínas Quinases p38 Ativadas por MitógenoRESUMO
Hepatocyte apoptosis by death receptors, hepatic inflammation, and fibrosis are prominent features of liver diseases. However, the link between these processes remains unclear. Our aim was to ascertain whether engulfment of apoptotic bodies by Kupffer cells promotes hepatic inflammation and fibrosis. Isolated murine Kupffer cells efficiently engulfed apoptotic bodies generated from UV-treated mouse hepatocytes. Engulfment of the apoptotic bodies, but not latex beads, stimulated Kupffer cell generation of death ligands, including Fas ligand, and tumor necrosis factor alpha (TNF-alpha). Both apoptotic body phagocytosis and death ligand generation were attenuated by gadolinium chloride, a Kupffer cell toxicant. Kupffer cells isolated from 3-day bile duct-ligated (BDL) mice were phenotypically similar to apoptotic body-"fed" Kupffer cells with enhanced death ligand expression; inhibition of hepatocyte apoptosis with a caspase inhibitor prevented this Kupffer cell activation. Consistent with a role for Kupffer cells in liver inflammation and fibrosis, gadolinium chloride attenuated neutrophil infiltration and markers for stellate cell activation. In conclusion, these findings support a model of cholestatic liver injury where Kupffer cell engulfment of apoptotic bodies promotes inflammation and fibrogenesis.
Assuntos
Apoptose , Citocinas/metabolismo , Hepatócitos/fisiologia , Células de Kupffer/fisiologia , Glicoproteínas de Membrana/metabolismo , Fagocitose/fisiologia , Fator de Necrose Tumoral alfa/metabolismo , Animais , Apoptose/fisiologia , Ductos Biliares , Proteína Ligante Fas , Gadolínio/farmacologia , Hepatite/patologia , Hepatócitos/metabolismo , Ligadura , Fígado/patologia , Fígado/fisiopatologia , Cirrose Hepática/patologia , CamundongosRESUMO
Bile acids induce hepatocyte injury by enhancing death receptor-mediated apoptosis. In this study, bile acid effects on TRAIL-mediated apoptosis were examined to gain insight into bile acid potentiation of death receptor signaling. TRAIL-induced apoptosis of HuH-7 cells, stably transfected with a bile acid transporter, was enhanced by bile acids. Caspase 8 and 10 activation, bid cleavage, cytosolic cytochrome c, and caspase 3 activation by TRAIL were all increased by the bile acid glycochenodeoxycholate (GCDCA). GCDCA (100 microm) did not alter expression of TRAIL-R1/DR4, TRAIL-R2/DR5, procaspase 8, cFLIP-L, cFLIP-s, Bax, Bcl-xL, or Bax. However, both caspase 8 and caspase 10 recruitment and processing within the TRAIL death-inducing signaling complex (DISC) were greater in GCDCA-treated cells whereas recruitment of cFLIP long and short was reduced. GCDCA stimulated phosphorylation of both cFLIP isoforms, which was associated with decreased binding to GST-FADD. The protein kinase C antagonist chelerythrine prevented bile acid-stimulated cFLIP-L and -s phosphorylation, restored cFLIP binding to GST-FADD, and attenuated bile acid potentiation of TRAIL-induced apoptosis. These results provide new insights into the mechanisms of bile acid cytotoxicity and the proapoptotic effects of cFLIP phosphorylation in TRAIL signaling.