RESUMO
Epidemiological studies have reported that exposure to toxic metals like cadmium (Cd) may promote the development of musculoskeletal diseases, such as osteoporosis, rheumatoid arthritis (RA), and osteoarthritis (OA), among others. The objective of this review is to summarize the molecular mechanisms of inflammation and oxidative stress activated by Cd at the bone level, particularly in osteoporosis, RA, and OA. Cadmium can increase bone resorption, affect the activity of osteoclasts and calcium (Ca) absorption, and impair kidney function, which favors the development of osteoporosis. In the case of RA, Cd interferes with the activity of antioxidant proteins, like superoxide dismutase (SOD) and catalase (CAT). It also promotes an inflammatory state, inducing the process of citrullination, which affects the proteins of immune response. On the other hand, accumulation of Cd in the tissues and blood of smokers has been related to the development of some musculoskeletal diseases. Therefore, knowing the negative impact of Cd toxicity at the articular level can help understand the damage mechanisms it produces, leading to the development of such diseases.
Assuntos
Cádmio/toxicidade , Poluentes Ambientais/toxicidade , Doenças Musculoesqueléticas/induzido quimicamente , Animais , Cádmio/normas , Exposição Ambiental/normas , Poluentes Ambientais/normas , HumanosRESUMO
Abstract An artificial liver support system is based on the functional hepatocytes being cultured inside a bioreactor; this technique has being used as an effective therapy for treating chronic liver diseases in recent times. This work evaluates different parameters such as cell viability and metabolic function of the hepatocytes when cultured on a hybrid scaffold. The scaffold was built using a polypyrrole plasma coated polymer layer seeded with endothelial matrix for efficient three-dimensional hepatocyte growth within a radial flow bioreactor. The flow rate inside the bioreactor was 7 ml / min. The parts for the bioreactor where either built using food-grade steel and/or glass or the scaffolds comprise a Poly (L-lactic acid)-coated polypyrrole iodine layer or not for HepG2 culture. The results show that the Poly (L-lactic acid)-coated scaffolds increased cell proliferation by 30%, protein production by 16% and albumin secretion by 40% compared with the non-coated scaffold. All experiments were performed thrice and data was analysed by ANOVA and Tukey statistic models with a p<0.05. The obtained results demonstrated that radial flow bioreactors in conjunction with hybrid scaffolds improve hepatocytes' physiological and functional properties and could be used as an alternative therapy for patients with liver diseases.
Resumen Un sistema de soporte hepático artificial se basa en utilizar hepatocitos funcionales cultivados en un biorreactor; esta técnica ha demostrado que se puede utilizar como una terapia eficaz para el tratamiento de enfermedades crónicas del hígado en los últimos tiempos. Este trabajo evalúa diferentes parámetros tales como la viabilidad celular y la función metabólica de los hepatocitos cuando se cultivan en un andamio híbrido. El andamio fue construido usando una capa de polímero recubierto de polipirrol plasma, se sembró con un cultivo tridimensional de células endoteliales y de hepatocitos dentro de un biorreactor de flujo radial. La velocidad de flujo en el interior del biorreactor fue de 7 ml / min. Las piezas para el biorreactor fueron construidas con acero de calidad alimentaria y / o vidrio. Los andamios control fueron de ácido L-poliláctico y a estos se les agrego un revestimiento de polipirrol-yodo para el cultivo de HepG2. Los resultados muestran que el ácido L-poliláctico recubierto, aumento la proliferación celular en un 30%, la producción de proteínas en un 16% y la secreción de albúmina por 40% en comparación con el andamio no recubierto. Todos los experimentos se llevaron a cabo tres veces y los datos se analizaron mediante modelos estadísticos ANOVA y Tukey con una p <0.05. Los resultados obtenidos demostraron que los biorreactores de flujo radial conjuntamente con andamios híbridos mejoran las propiedades fisiológicas y funcionales hepatocitos y podrían utilizarse como una terapia alternativa para los pacientes con enfermedades hepáticas crónicas.
RESUMO
Although the liver is a cadmium-target organ, hepatocyte response involved in its toxicity is not yet elucidated. A link between this heavy metal treatment and Stat3 signaling pathways was examined in primary mouse hepatocytes. We provided evidence of a novel link among NADPH oxidase and Stat3 signaling, mediated by Src, EGFR, and Erk1/2. Cadmium activates NADPH oxidase. ROS produced by this oxidase activates Src, enable that in turn, transactivates EGFR that activates Stat3 in tyrosine, allowing its dimerization. Also, ROS from NADPH oxidase favors ERK1/2 activation that phosphorylates Stat3 in serine, resulting in a compensatory or adaptive survival response such as production of metallothionein-II in short Cd exposure times. However, after 12h CdCl2 treatment, cell viability diminished in 50%, accompanied by a drastic decrease of metallothionein-II production, and an increase in p53 activation and the pro-apoptotic protein Bax.
Assuntos
Cádmio/toxicidade , Poluentes Ambientais/toxicidade , Hepatócitos/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Sobrevivência Celular , Células Cultivadas , Receptores ErbB/metabolismo , Hepatócitos/metabolismo , Masculino , Metalotioneína/metabolismo , Camundongos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , NADPH Oxidases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Fator de Transcrição STAT3/metabolismo , Quinases da Família src/metabolismoRESUMO
Overproduction of collagen (I) by activated hepatic stellate cells is a critical step in the development of liver fibrosis. It has been established that these cells express interleukin (IL)-6 and respond to this cytokine with an increase in alpha(I) collagen. Pentoxifylline, a methylxanthine derivate, has been reported to have antifibrotic properties, but the mechanism responsible for this effect is unknown. The aim of this study was to determine the effect of pentoxifylline on acetaldehyde-induced collagen production in a rat hepatic stellate cell line (CFSC-2G cells). Cells were treated with 100 microM acetaldehyde and 200 microM pentoxifyline for 3 h. IL-6 and alpha(I) collagen messenger RNA (mRNA) were determined by reverse transcriptase polymerase chain reaction (RT-PCR) assay. NFkappaB activation was determined by electrophoretic mobility shift assay. To corroborate NFkappaB participation in pentoxifylline effect, cells were pretreated with 10 microM TPCK, a NFkappaB inhibitor. IkappaBalpha was determined by Western blot. IL-6 expression decreased significantly in acetaldehyde-pentoxifylline-treated cells. Acetaldehyde-treated cells pretreated with an anti-IL-6 monoclonal antibody did not show any increase in alpha (I) collagen expression. Acetaldehyde-treated cells increased 1.48 times NFkappaB activation, whereas acetaldehyde-pentoxifylline-treated cells decreased NFkappaB activation to control values. TPCK pretreated acetaldehyde cells did not present NFkappaB activation. To corroborate NFkappaB participation in pentoxifylline effect, IkappaBalpha was determined. IkappaBalpha protein level decreased 50% in acetaldehyde-treated cells, while acetaldehyde-pentoxifylline-treated cells showed IkappaBalpha control cells value. The data suggest that acetaldehyde induced alpha(I) collagen and IL-6 expression via NFkappaB activation. Pentoxifylline prevents acetaldehyde-induced alpha(I) collagen and IL-6 expression by a mechanism dependent on IkappaBalpha degradation, which in turn blocks NFkappaB activation.
Assuntos
Colágeno Tipo I/metabolismo , Proteínas I-kappa B/metabolismo , Cirrose Hepática/prevenção & controle , Fígado/efeitos dos fármacos , NF-kappa B/antagonistas & inibidores , Pentoxifilina/farmacologia , Acetaldeído/farmacologia , Animais , Anticorpos Monoclonais , Western Blotting , Linhagem Celular , Colágeno Tipo I/genética , Ensaio de Desvio de Mobilidade Eletroforética , Interleucina-6/imunologia , Interleucina-6/metabolismo , Fígado/metabolismo , Fígado/patologia , Cirrose Hepática/metabolismo , Cirrose Hepática/patologia , Inibidor de NF-kappaB alfa , NF-kappa B/metabolismo , RNA Mensageiro/metabolismo , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Tempo , Tosilfenilalanil Clorometil Cetona/farmacologiaRESUMO
The cellular and humoral natural immune response induced by hepatitis C virus (HCV) is commonly unable to eradicate the virus. HCV is a highly mutable, hepatotropic RNA virus that causes acute and chronic hepatitis, an infection that involves the production of various cytokines. The aim of the study is to analyse the expression of pro-inflammatory cytokines IL-1beta, TNF-alpha, IFN-gamma and the chemokine CXCL8 (IL-8) in liver tissue and their expression and secretion in PBMC of patients with chronic hepatitis C (CHC), in response to pentoxyfilline (PTX). We studied six CHC patients, naive to treatment. Patients received PTX 400 mg twice a day/8 weeks. Pentoxyfilline resulted in decreased expression of mRNA of liver IL-1beta, TNF-alpha and IFN-gamma: 144.2 versus 83.5 molecules of IL-1beta (P < 0.05), TNF-alpha 194.3 versus 17.6 molecules (P = 0.03) and IFN-gamma 26.1 versus 0.5 molecules (P = 0.04). Following PTX, PBMC exhibited a decrease in IFN-gamma mRNA 12.2 versus 1.5 molecules (P = 0.028) and CXCL8 4.2 versus 2.5 molecules (P = 0.027). In PBMC, only the secretion of TNF-alpha was decreased 1109 versus 933.5 pg/ml, P = 0.046. Production of cytokines both locally (within the liver) and systemically (PBMC) may serve as biomarkers of the infection with hepatitis C. PTX inhibits the expression of several pro-inflammatory cytokines in the liver. These results indicate that it is worth exploring PTX in hepatitis in future clinical trials in nonresponders to antiviral treatment.
Assuntos
Citocinas/biossíntese , Hepatite C Crônica/tratamento farmacológico , Hepatite C Crônica/imunologia , Mediadores da Inflamação/metabolismo , Pentoxifilina/farmacologia , Adulto , Citocinas/antagonistas & inibidores , Citocinas/sangue , Citocinas/genética , Feminino , Hepacivirus/imunologia , Hepatite C Crônica/metabolismo , Humanos , Mediadores da Inflamação/sangue , Interferon gama/antagonistas & inibidores , Interferon gama/biossíntese , Interferon gama/sangue , Interleucina-1/biossíntese , Interleucina-1/sangue , Interleucina-8/biossíntese , Interleucina-8/sangue , Pessoa de Meia-Idade , RNA Mensageiro/antagonistas & inibidores , RNA Mensageiro/biossíntese , Fator de Necrose Tumoral alfa/biossínteseRESUMO
BACKGROUND: Interferon-based therapy induces changes in viral dynamics in chronic hepatitis C (CHC) patients. AIMS: The aim of this study was to assess early hepatitis C virus (HCV)-RNA changes and evaluate its predictive value to achieve sustained viral response (SVR) in patients with CHC treated with peginterferon alpha-2b weekly plus ribavirin daily for 48 weeks. METHODS: HCV-RNA was measured at baseline, 48 h, 4, 12, 24 and 48 weeks of treatment and 24 weeks after treatment. RESULTS: Eighteen HCV genotype 1 patients were included (13 male, five female) with a mean age of 44.4+/-11.9 years. Nine patients achieved SVR (50%). Viral decline occurred as early as 48 h; the magnitude of decline was statistically different between both groups (P<0.01). Responders had a > or =1 log(10) drop in HCV-RNA at 48 h (positive predictive value (PPV) of 89% to achieve SVR) that persisted at week 4. By week 12, serum HCV-RNA was undetectable (PPV 100%). CONCLUSIONS: Our data indicate that peginterferon alpha-2b plus ribavirin treatment produces significant changes in HCV dynamics that can be detected as early as 48 h after the first dose of peginterferon alpha-2b and that these changes are useful in predicting response to therapy in CHC patients.
Assuntos
Antivirais/uso terapêutico , Hepacivirus/efeitos dos fármacos , Hepatite C Crônica/tratamento farmacológico , Interferon-alfa/uso terapêutico , Ribavirina/uso terapêutico , Adolescente , Adulto , Idoso , Alanina Transaminase/sangue , Feminino , Hepacivirus/genética , Hepatite C Crônica/sangue , Hepatite C Crônica/virologia , Humanos , Interferon alfa-2 , Masculino , Pessoa de Meia-Idade , Polietilenoglicóis , RNA Viral/efeitos dos fármacos , Proteínas Recombinantes , Resultado do Tratamento , Carga Viral , Viremia/tratamento farmacológico , Viremia/virologiaRESUMO
Pretreatment with zinc produces tolerance to several cadmium toxic effects. This study was performed to further elucidate the mechanism of zinc-induced tolerance to cadmium cytotoxicity in a rat hepatic stellate cell line (CFSC-2G). Twenty four hours after seeding, cells were treated with 60 micromol/L ZnCl2 for 24 h. Following zinc pretreatment, cells were exposed to 3 micromol/L and 5 micromol/L CdCl2 for an additional 24 h. The toxicity of cadmium was significantly reduced in the zinc-pretreated cells. Zinc pretreatment produced a decrease in lipid peroxidation damage of cadmium-treated cells. Glutathione cell content diminished 33% and 43% as a result of 3 micromol/L and 5 micromol/ L CdCl2 treatment, respectively. Cell pretreatment with zinc recovered glutathione content at control cells level. Catalase and glutathione peroxidase activities were also recovered to control values with zinc pretreatment. Cadmium (5 micromol/L) was able to induce 39% the expression of alpha1 collagen (I) gene after 1 h treatment, while zinc pretreatment prevented this cadmium profibrogenic effect. We also examined the production of heat shock protein 70 (Hsp70) as a cellular response to oxidative stress produced by cadmium. By Western blot analysis, a 1.3 and 3 times increment in Hsp70, with 3 micromol/L and 5 micromol/L CdCl2 treatment, respectively, was observed. Zinc pretreatment prevented the production of Hsp70. Metallothionein-II (MT-II) gene expression was induced by cadmium, but the induction was unaffected with zinc pretreatment. These data suggest that zinc-induced protection against the cytotoxicity of cadmium in stellate cells may be related to the maintenance of normal redox balance inside the cell.
Assuntos
Cádmio/toxicidade , Peroxidação de Lipídeos/efeitos dos fármacos , Substâncias Protetoras/farmacologia , Zinco/farmacologia , Animais , Catalase/metabolismo , Linhagem Celular , Colágeno Tipo I/biossíntese , Colágeno Tipo I/genética , Expressão Gênica , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Glutationa Redutase/metabolismo , Fígado/efeitos dos fármacos , Fígado/enzimologia , Fígado/metabolismo , Estresse Oxidativo , Pró-Colágeno/biossíntese , Pró-Colágeno/genética , Ratos , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
The effect of pentoxifylline (PTX), a methylxanthine derivative, on collagen induction and secretion and on the production of mRNA of two fibrogenic cytokines: interleukin-6 and transforming growth factor-beta(1) (IL-6 and TGF-beta(1)) in a rat hepatic stellate cell line (CFSC-2G) exposed to acetaldehyde was studied. CFSC-2G cells were treated with 175 microM acetaldehyde for 24h. The cells were then exposed to a medium containing 200 microM PTX. Collagen secretion, increased 2.6 times in acetaldehyde treated cells. Cells exposed to acetaldehyde and treated with PTX diminished collagen secretion to control values and decreased alpha(1)(I) collagen mRNA by 15%. Reverse transcriptase-polymerase chain reaction (RT-PCR) assays of TGF-beta(1) mRNA showed no variation in different experimental conditions. However, PTX induced a decrease of 32% in IL-6 mRNA in acetaldehyde-treated cells. CFSC-2G cells treated with anti-IL-6 monoclonal antibody, 15min before acetaldehyde was added, did not present an increase in alpha(1)(I) collagen mRNA. These results show that PTX inhibits the expression of alpha(1)(I) collagen via the inhibition of IL-6 in acetaldehyde treated cells. The effect herein reported on IL-6 and alpha(1)(I) collagen mRNA adds to the previously described effect of PTX, which could be useful in the fibrogenic process induced by acetaldehyde.
Assuntos
Colágeno Tipo I/metabolismo , Interleucina-6/biossíntese , Fígado/metabolismo , Pentoxifilina/farmacologia , Pró-Colágeno/metabolismo , Acetaldeído/farmacologia , Animais , Northern Blotting , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Fígado/citologia , Fígado/efeitos dos fármacos , Pentoxifilina/toxicidade , RNA Mensageiro/análise , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fator de Crescimento Transformador beta/biossínteseRESUMO
Metadoxine (pyridoxine-pyrrolidone carboxylate) has been reported to improve liver function tests in alcoholic patients. In the present work we have investigated the effect of metadoxine on some parameters of cellular damage in hepatocytes and hepatic stellate cells in culture treated with ethanol and acetaldehyde. HepG2 and CFSC-2G cells were treated with 50 mM ethanol or 175 microM acetaldehyde as initial concentration in the presence or absence of 10 microg ml(-1) of metadoxine. Twenty-four hours later reduced and oxidized glutathione content, lipid peroxidation damage, collagen secretion and IL-6, IL-8 and TNF- alpha secretion were determined. Our results suggest that metadoxine prevents glutathione depletion and the increase in lipid peroxidation damage caused by ethanol and acetaldehyde in HepG2 cells. In hepatic stellate cells, metadoxine prevents the increase in collagen and attenuated TNF- alpha secretion caused by acetaldehyde. Thus, metadoxine could be useful in preventing the damage produced in early stages of alcoholic liver disease as it prevents the redox imbalance of the hepatocytes and prevents TNF- alpha induction, one of the earliest events in hepatic damage.