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1.
Eur Rev Med Pharmacol Sci ; 24(10): 5758-5768, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32495912

RESUMO

OBJECTIVE: Hepatitis C virus (HCV) infection is a global epidemic, still highly prevalent in Europe. Given efficacy and safety of HCV therapy by Direct Antiviral Agents (DAA), World Health Organization called for actions to eliminate HCV infection. A limit is represented by access to care, mostly due to the high costs of medicines. In Italy, in 2015, the access to DAA therapy was reimbursed for patients with advanced disease, whereas in 2017 universal access was granted. The aim of this study was to analyse changes in patient recruitment trends treated with DAA with or without limitations to access to therapy. PATIENTS AND METHODS: 165,105 patients treated with DAA in Italy from 2015 to December 2018 were analysed. Daily patient treatment rate was obtained by segmented regression of interrupted time series analysis. RESULTS: 74,199 patients with advanced disease (62% with cirrhosis) had access to the therapy during the time period from 2015 to 2017. Following the extension of reimbursement criteria, 90,906 additional patients were treated (43.2% with F0-F1 and 22.9% with F2), with an absolute reduction of 59.9% of patients with advanced disease (cirrhosis decreased to 18.5%). Segmented regression of interrupted time series analysis of daily patient treatment rate showed a progressive reduction of patients with advanced disease, offset by those with initial disease. Notably, elimination of restrictions to therapy did not change the overall treatment rate. CONCLUSIONS: This study showed that a no-limit reimbursement policy for DAAs prescriptions to HCV infected individuals in Italy widened the types of treated patients, but the process towards elimination of HCV infection was not significantly changed.


Assuntos
Antivirais/farmacologia , Hepacivirus/efeitos dos fármacos , Hepatite C/tratamento farmacológico , Sistema de Registros , Humanos , Itália
2.
Biochim Biophys Acta Mol Basis Dis ; 1864(4 Pt B): 1335-1344, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-28916388

RESUMO

BACKGROUND AND AIMS: Cholangiocarcinoma (CCA) is an aggressive tumor type affecting cholangiocytes. CCAs frequently arise under certain cholestatic liver conditions. Intrahepatic accumulation of bile acids may facilitate cocarcinogenic effects by triggering an inflammatory response and cholangiocyte proliferation. Here, the role of bile acid receptors FXR and TGR5 in CCA progression was evaluated. METHODS: FXR and TGR5 expression was determined in human CCA tissues and cell lines. An orthotopic model of CCA was established in immunodeficient mice and tumor volume was monitored by magnetic resonance imaging under chronic administration of the specific FXR or TGR5 agonists, obeticholic acid (OCA) or INT-777 (0,03% in chow; Intercept Pharmaceuticals), respectively. Functional effects of FXR or TGR5 activation were evaluated on CCA cells in vitro. RESULTS: FXR was downregulated whereas TGR5 was upregulated in human CCA tissues compared to surrounding normal liver tissue. FXR expression correlated with tumor differentiation and TGR5 correlated with perineural invasion. TGR5 expression was higher in perihilar than in intrahepatic CCAs. In vitro, FXR was downregulated and TGR5 was upregulated in human CCA cells compared to normal human cholangiocytes. OCA halted CCA growth in vivo, whereas INT-777 showed no effect. In vitro, OCA inhibited CCA cell proliferation and migration which was associated with decreased mitochondrial energy metabolism. INT-777, by contrast, stimulated CCA cell proliferation and migration, linked to increased mitochondrial energy metabolism. CONCLUSION: Activation of FXR inhibits, whereas TGR5 activation may promote, CCA progression by regulating proliferation, migration and mitochondrial energy metabolism. Modulation of FXR or TGR5 activities may represent potential therapeutic strategies for CCA.


Assuntos
Neoplasias dos Ductos Biliares/patologia , Colangiocarcinoma/patologia , Fármacos Gastrointestinais/farmacologia , Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Idoso , Idoso de 80 Anos ou mais , Animais , Ácidos e Sais Biliares/metabolismo , Neoplasias dos Ductos Biliares/tratamento farmacológico , Ductos Biliares/citologia , Ductos Biliares/efeitos dos fármacos , Ductos Biliares/metabolismo , Ductos Biliares/patologia , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Ácido Quenodesoxicólico/análogos & derivados , Ácido Quenodesoxicólico/farmacologia , Colangiocarcinoma/tratamento farmacológico , Ácidos Cólicos/farmacologia , Estudos de Coortes , Progressão da Doença , Metabolismo Energético/efeitos dos fármacos , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Feminino , Fármacos Gastrointestinais/uso terapêutico , Humanos , Masculino , Camundongos , Camundongos Nus , Pessoa de Meia-Idade , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Receptores Citoplasmáticos e Nucleares/agonistas , Receptores Acoplados a Proteínas G/agonistas , Ensaios Antitumorais Modelo de Xenoenxerto
3.
Semin Liver Dis ; 37(1): 45-55, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-28201848

RESUMO

Polycystic liver diseases (PLDs) include a heterogeneous group of congenital disorders inherited as dominant or recessive genetic traits; they are manifested alone or in association with polycystic kidney disease. Ductal plate malformation during embryogenesis and the loss of heterozygosity linked to second-hit mutations may promote the dilatation and/or development of a large number (> 20) of biliary cysts, which are the main cause of morbidity in these patients. Surgical procedures aimed to eliminate symptomatic cysts show short-term beneficial effects, but are not able to block the disease progression. Therefore, liver transplantation is the only curative option. Intense studies on the molecular mechanisms involved in the pathogenesis of PLDs have resulted in different clinical trials, some of them with promising outcomes. Here the authors summarize the key aspects of PLD etiology, pathogenesis, and therapy, highlighting the most recent advances and future research directions.


Assuntos
Cistos , Hepatopatias , Cistos/genética , Cistos/patologia , Cistos/terapia , Progressão da Doença , Humanos , Hepatopatias/genética , Hepatopatias/patologia , Hepatopatias/terapia , Transplante de Fígado , Mutação , Fenótipo
4.
Clin Exp Immunol ; 185(1): 61-71, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26864161

RESUMO

The diagnosis of primary sclerosing cholangitis (PSC) is difficult due to the lack of sensitive and specific biomarkers, as is the early diagnosis of cholangiocarcinoma (CC), a complication of PSC. The aim of this study was to identify specific serum miRNAs as diagnostic biomarkers for PSC and CC. The levels of 667 miRNAs were evaluated in 90 human serum samples (30 PSC, 30 CC and 30 control subjects) to identify disease-associated candidate miRNAs (discovery phase). The deregulated miRNAs were validated in an independent cohort of 140 samples [40 PSC, 40 CC, 20 primary biliary cirrhosis (PBC) and 40 controls]. Receiver operating characteristic (ROC) curves were established and only miRNAs with an area under the curve (AUC) > 0·70 were considered useful as biomarkers. In the discovery phase we identified the following: 21 miRNAs expressed differentially in PSC, 33 in CC and 26 in both in comparison to control subjects as well as 24 miRNAs expressed differentially between PSC and CC. After the validation phase, miR-200c was found to be expressed differentially in PSC versus controls, whereas miR-483-5p and miR-194 showed deregulated expression in CC compared with controls. We also demonstrate a difference in the expression of miR-222 and miR-483-5p in CC versus PSC. Combination of these specific miRNAs further improved the specificity and accuracy of diagnosis. This study provides a basis for the use of miRNAs as biomarkers for the diagnosis of PSC and CC.


Assuntos
Biomarcadores Tumorais/genética , Colangiocarcinoma/diagnóstico , Colangite Esclerosante/diagnóstico , Regulação Neoplásica da Expressão Gênica , Cirrose Hepática Biliar/diagnóstico , Adulto , Idoso , Área Sob a Curva , Biomarcadores Tumorais/sangue , Estudos de Casos e Controles , Colangiocarcinoma/sangue , Colangiocarcinoma/genética , Colangiocarcinoma/patologia , Colangite Esclerosante/sangue , Colangite Esclerosante/genética , Colangite Esclerosante/patologia , Diagnóstico Diferencial , Feminino , Perfilação da Expressão Gênica , Humanos , Cirrose Hepática Biliar/sangue , Cirrose Hepática Biliar/genética , Cirrose Hepática Biliar/patologia , Masculino , MicroRNAs/sangue , MicroRNAs/genética , Pessoa de Meia-Idade , Curva ROC
6.
Gut ; 58(7): 990-7, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18829977

RESUMO

BACKGROUND AND AIMS: Progression of chronic cholestatic disorders towards ductopenia results from the dysregulation of cholangiocyte survival, with cell death by apoptosis prevailing over compensatory proliferation. Currently, no therapy is available to sustain cholangiocyte survival in the course of those disorders. It was recently shown that cholangiocytes express the glucagon-like peptide-1 receptor (GLP-1R); its activation results in enhanced proliferative reaction to cholestasis. The GLP-1R selective agonist exendin-4 sustains pancreatic beta cell proliferation and prevents cell death by apoptosis. Exendin-4 is now employed in humans as a novel therapy for diabetes. The aim of the present study was to verify whether exendin-4 is effective in preventing cholangiocyte apoptosis. METHODS: In vitro, tests were carried out to determine if exendin-4 is able to prevent apoptosis of cholangiocytes isolated from normal rats induced by glycochenodeoxycholic acid (GCDCA); in vivo, animals subjected to 1 week of bile duct ligation and to a single intraperitoneal injection of CCl(4) were treated with exendin-4 for 3 days. RESULTS: Exendin-4 prevented GCDCA-induced Bax mitochondrial translocation, cytochrome c release and an increase in caspase 3 activity. Phosphatidylinositol 3-kinase, but not cAMP/protein kinase A or Ca(2+)/calmodulin-dependent protein kinase inhibitors, neutralised the effects of exendin-4. In vivo, exendin-4 administration prevented the increase in TUNEL (terminal deoxynucleotidyl transferase-mediated triphosphate end-labelling)-positive cholangiocytes and the loss of bile ducts observed in bile duct-ligated rats treated with CCl(4). CONCLUSION: Exendin-4 prevents cholangiocyte apoptosis both in vitro and in vivo; such an effect is due to the ability of exendin-4 to counteract the activation of the mitochondrial pathway of apoptosis. These findings support the hypothesis that exendin-4 may be effective in slowing down the progression of cholangiopathies to ductopenia.


Assuntos
Apoptose/efeitos dos fármacos , Ductos Biliares/efeitos dos fármacos , Colestase/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Peptídeos/uso terapêutico , Receptores de Glucagon/agonistas , Peçonhas/uso terapêutico , Animais , Ductos Biliares/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Exenatida , Receptor do Peptídeo Semelhante ao Glucagon 1 , Masculino , Ratos , Ratos Endogâmicos F344
7.
Dig Liver Dis ; 41(7): 523-33, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18948067

RESUMO

BACKGROUND/AIMS: Incidence of cholangiocarcinoma is increasing worldwide, yet remaining highly aggressive and with poor prognosis. The mechanisms that drive cholangiocyte transition towards malignant phenotype are obscure. Cholangiocyte benign proliferation is subjected to a self-limiting mechanism based on the autocrine release of endogenous opioid peptides. Despite the presence of both, ligands interact with delta opioid receptor (OR), but not with microOR, with the consequent inhibition of cell growth. We aimed to verify whether cholangiocarcinoma growth is associated with failure of opioidergic regulation of growth control. METHODS: We evaluated the effects of OR selective agonists on cholangiocarcinoma cell proliferation, migration and apoptosis. Intracellular signals were also characterised. RESULTS: Activation of microOR, but not deltaOR, increases cholangiocarcinoma cell growth. Such an effect is mediated by ERK1/2, PI3K and Ca(2+)-CamKIIalpha cascades, but not by cAMP/PKA and PKCalpha. microOR activation also enhances cholangiocarcinoma cell migration and reduces death by apoptosis. The anti-apoptotic effect of microOR was PI3K dependent. CONCLUSIONS: Our data indicate that cholangiocarcinoma growth is associated with altered opioidergic regulation of cholangiocyte biology, thus opening new scenarios for future surveillance or early diagnostic strategies for cholangiocarcinoma.


Assuntos
Proliferação de Células , Colangiocarcinoma/patologia , Receptores Opioides delta/metabolismo , Receptores Opioides mu/metabolismo , Apoptose , Linhagem Celular Tumoral , Movimento Celular , Colangiocarcinoma/metabolismo , Humanos , Transdução de Sinais
8.
Gut ; 57(3): 352-64, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17989109

RESUMO

BACKGROUND: Endogenous opioids modulate the growth of nervous and non-nervous cells. Hepatic stellate cells (HSCs) are the main cell phenotype involved in liver fibrogenesis, display molecular markers of neuronal cells and respond to neurotransmitters. AIM: To evaluate the role of endogenous opioids on liver fibrogenesis. METHODS: Activated rat HSCs (passage 1-3) were used to evaluate cell proliferation and intracellular signalling pathway activation. Liver fibrosis was induced in rats by dimethylnitrosamine (DMN) administration. RESULTS: Opioid receptors showed a different pattern of expression when measured in quiescent and activated (in vitro and in vivo) HSCs. The activation of opioid receptors increased HSC proliferation and collagen accumulation. Opioid receptor stimulation induced a calcium-dependent protein kinase C alpha (PKC alpha)/extracellular regulated kinase (ERK)/phosphatidylinositol 3-kinase (PI3K) pathway activation that mediated the effect of endogenous opioids on HSC proliferation and collagen synthesis. In DMN-treated rats, the opioid antagonist naloxone reduced alpha-smooth muscle actin expression (as a marker of HSC activation) and collagen deposition, both measured by morphometry after 5 weeks of treatment. In both DMN-treated rats and human liver biopsies from chronic liver diseases, opioid receptors were observed in HSCs in area of active fibrogenesis. The endogenous opioid met-enkephalin increased its expression in zone 3 hepatocytes close to the area of necrosis after DMN administration and in the cellular target of chronic liver injury in human biopsies, and stimulated HSC proliferation and collagen synthesis. CONCLUSIONS: Endogenous opioids released during chronic liver injury participate in the process of liver fibrogenesis by stimulating HSC proliferation and collagen production in a paracrine manner.


Assuntos
Hepatócitos/fisiologia , Cirrose Hepática Experimental/patologia , Peptídeos Opioides/fisiologia , Animais , Proliferação de Células , Células Cultivadas , Doença Crônica , Colágeno Tipo I/metabolismo , Dimetilnitrosamina , Progressão da Doença , Encefalina Metionina/metabolismo , Encefalina Metionina/farmacologia , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Humanos , Fígado/metabolismo , Cirrose Hepática Experimental/induzido quimicamente , Cirrose Hepática Experimental/metabolismo , Hepatopatias/metabolismo , Masculino , Comunicação Parácrina , Ratos , Receptores Opioides/metabolismo , Transdução de Sinais/fisiologia
9.
Dig Liver Dis ; 39(1): 60-9, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16982221

RESUMO

BACKGROUND: Cells within the acidic extracellular environment of solid tumours maintain their intracellular pH through the activity of the Na(+)/H(+) exchanger and the Na(+) dependent Cl(-)/HCO(3)(-) exchanger. The inhibition of these mechanisms could therefore inhibit cancer cell growth. AIM: We evaluated the effect of two selective inhibitors of these transporters (cariporide and S3705) on proliferation and apoptosis of human cholangiocarcinoma cells (HUH-28 and Mz-ChA-1 cells) as a function of external pH (7.4 and 6.8). METHODS/RESULTS: HUH-28 cells incubated for 24h at external pH 7.4 or 6.8 without inhibitors maintained intracellular pH at physiological level, whereas incubation with cariporide and/or S3705 caused the intracellular pH of cells to drop. Incubation of HUH-28 cells with cariporide and/or S3705 was able to reduce proliferation, evaluated by a colorimetric ELISA method, and to induce apoptosis, evaluated by measuring caspase-3 activity and Annexin-V staining, and these effects were more evident at external pH 6.8. S3705 but not cariporide was able to inhibit serum-induced phosphorylation of ERK1/2, AKT and BAD, intracellular molecules involved in cancer cell proliferation and survival. Similar results were obtained in Mz-ChA-1 cells. CONCLUSIONS: (1) Inhibition of intracellular pH regulatory mechanisms by cariporide and S3705 reduces proliferation and induces apoptosis in cholangiocarcinoma cells; and (2) these drugs might have potential therapeutic value against cholangiocarcinoma.


Assuntos
Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Antiportadores de Cloreto-Bicarbonato/antagonistas & inibidores , Colangiocarcinoma/tratamento farmacológico , Líquido Intracelular/efeitos dos fármacos , Trocadores de Sódio-Hidrogênio/antagonistas & inibidores , Western Blotting , Linhagem Celular , Colangiocarcinoma/metabolismo , Colangiocarcinoma/patologia , Guanidinas/antagonistas & inibidores , Humanos , Concentração de Íons de Hidrogênio , Ionóforos/farmacologia , Nigericina/farmacologia , Sulfonas/antagonistas & inibidores
10.
Dig Liver Dis ; 37(11): 869-76, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16169303

RESUMO

BACKGROUND: Silybin, the main active component of silymarin, has been reported to reduce hepatic fibrosis by 30% in bile duct ligated rats, whereas Vitamin E alone does not significantly modify liver damage and collagen deposition in chronic liver injury. AIM: The aim of the present study was to evaluate the hepatoprotective and the antifibrotic properties of a new silybin-phosphatidylcholine-Vitamin E complex, characterised by elevated oral bioavailability and lipophilicity, on rat hepatic fibrosis induced by dimethylnitrosamine administration and by bile duct ligation. METHODS/RESULTS: The complex was administered by gastric gavage at a dose of 250 and 75 mg/kg (as silybin and Vitamin E, respectively). Treatment with the complex was able to prevent the dimethylnitrosamine-induced loss in body and liver weight, as well as to reduce the degree of liver injury, as determined by alanine aminotransferase values and necroinflammatory score. This was associated with reduced hepatic stellate cells proliferation both after 1 and 5 weeks of treatment. Treatment with the complex reduced also hepatic stellate cells activation and collagen deposition. Treatment with dimethylnitrosamine induced an increase in alpha1(I) procollagen, TGF(beta1), tissue inhibitor of metalloproteinase 1 and metalloproteinase 2 mRNA expression, which were significantly reduced by administration of the complex. In the bile duct ligation model, the administration of the complex was able to reduce hepatic stellate cells proliferation and activation, as well as collagen deposition and alpha1(I) procollagen mRNA expression. CONCLUSIONS: These results suggest that this new silybin-phosphatidylcholine-Vitamin E complex could be an interesting drug to be tested in patients with chronic liver disease.


Assuntos
Antioxidantes/farmacologia , Cirrose Hepática/tratamento farmacológico , Fosfatidilcolinas/farmacologia , Silimarina/farmacologia , Vitamina E/farmacologia , Animais , Disponibilidade Biológica , Combinação de Medicamentos , Cirrose Hepática/patologia , Cirrose Hepática/prevenção & controle , Masculino , Metaloproteinase 2 da Matriz/análise , Ratos , Ratos Sprague-Dawley , Inibidor Tecidual de Metaloproteinase-1/análise
11.
Dig Liver Dis ; 36(11): 744-51, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15571005

RESUMO

BACKGROUND: Pirfenidone (5 methyl-1-phenyl-2(1H)-pyridone) is a novel anti-fibrotic agent, which has been shown to decrease collagen deposition in a variety of animal models in vivo, and recently in hepatic fibrosis also. At cellular level, we have recently demonstrated that pirfenidone is able to inhibit proliferation of hepatic stellate cells induced by platelet-derived growth factor, as well as collagen type I accumulation and alpha1(I) procollagen mRNA expression. AIMS: To evaluate if pirfenidone maintains its anti-fibrotic properties also when administered after the induction of hepatic damage and to further investigate the molecular mechanisms leading to the anti-fibrotic effect of pirfenidone. METHODS AND RESULTS: Rats treated with dimethylnitrosamine (10 mg/kg) for 5 weeks received a liquid diet containing 0.5% pirfenidone starting from the third week. Pirfenidone treatment reduced the degree of liver injury, as determined by alanine aminotransferase values and necro-inflammatory score, which was associated with reduced hepatic stellate cells proliferation and collagen deposition. Treatment with dimethylnitrosamine increased transcripts levels for transforming growth factorbeta1, procollagen alpha1(I), tissue inhibitors of metalloproteinase-1 and matrix metalloproteinase-2 by 7-, 7-, 4- and 15-fold, respectively. Pirfenidone administration downregulated elevated levels of those transcripts by 50-60%, and this was associated with a 70% reduction in collagen deposition. CONCLUSIONS: (1) Pirfenidone is effective also if administered after the induction of the hepatic damage; (2) the anti-fibrotic effect of pirfenidone is mainly due to the reduced expression of profibrogenic procollagen alpha1(I) and TIMP-1, most likely through the downregulation of transforming growth factorbeta1 mRNA, and of matrix metalloproteinase-2, which is mainly implicated in the degradation of the normal extracellular matrix.


Assuntos
Colágeno Tipo I/fisiologia , Regulação para Baixo , Cirrose Hepática/tratamento farmacológico , Cirrose Hepática/fisiopatologia , Metaloproteinase 2 da Matriz/fisiologia , Piridonas/uso terapêutico , Inibidor Tecidual de Metaloproteinase-1/fisiologia , Animais , Masculino , Ratos , Ratos Sprague-Dawley
12.
Hepatology ; 34(5): 868-76, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11679956

RESUMO

Bile acids (BA) enter cholangiocytes by the Na(+)-dependent apical BA transporter (ABAT). By this mechanism, taurocholate (TC) and taurolithocholate (TLC) increase cholangiocyte proliferation. No in vivo studies exist regarding the anatomical sites involved in BA-regulation of cholangiocyte growth. Specific cholangiocyte subpopulations participate in BA-regulated proliferation. Proliferation was assessed in liver sections by determining the number of proliferating cellular nuclear antigen (PCNA)-positive cholangiocytes and cytokeratin-19 (CK-19)-positive ducts. We isolated small and large cholangiocytes from rats fed for 1 week TC, TLC, or BA control diet and determined PCNA and ABAT expression and BA transport activity. We evaluated if TC and TLC induction of ABAT expression was dependent on activation of PKC alpha. DNA replication was active only in large normal cholangiocytes. TC and TLC feeding increased proliferation of large cholangiocytes, induced the de novo activation of proliferation of small cholangiocytes, overexpression of ABAT and BA transport activity in large cholangiocytes, and de novo expression of ABAT and BA transport activity in small cholangiocytes. BA-stimulated ABAT expression was dependent on PKC activation in cholangiocytes. TC and TLC stimulate proliferation of small and large cholangiocytes associated with PKC-dependent up-regulation of ABAT.


Assuntos
Ductos Biliares/citologia , Ductos Biliares/metabolismo , Proteínas de Transporte/metabolismo , Hidroxiesteroide Desidrogenases , Glicoproteínas de Membrana , Ácido Taurocólico/farmacologia , Ácido Taurolitocólico/farmacologia , Administração Oral , Animais , Ductos Biliares/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Tamanho Celular , Isoenzimas/fisiologia , Masculino , Proteína Quinase C/fisiologia , Proteína Quinase C-alfa , Ratos , Ratos Endogâmicos F344
13.
J Hepatol ; 34(3): 378-85, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11322198

RESUMO

BACKGROUND/AIMS: The Na+/H+ exchanger is involved in rat hepatic stellate cell (HSC) proliferation induced by platelet-derived growth factor (PDGF). We therefore evaluated in human HSC: (1) the mechanisms of intracellular pH regulation; (2) the relationship between Na+/H+ exchange activation and cell proliferation induced by PDGF, insulin-like growth factor 1 (IGF-1) and insulin. METHODS/RESULTS: pH(i) regulation was mainly dependent on the activity of the Na+/H+ exchanger, which was evaluated by measuring pH(i) recovery from an acute acid load. PDGF (25 ng/ml) gradually increased the activity of the Na+/H+ exchanger which peaked at 18 h and remained stable until the 24th h. IGF-1 (10 nmol/l), but not insulin (100 nmol/l), slightly but significantly increased the activity of the Na+/H+ exchanger. Amiloride (100 micromol/l) and 20 micromol/l 5-N-ethyl-N-isopropyl-amiloride completely inhibited HSC proliferation (evaluated by measurement of bromodeoxyuridine incorporation) induced by PDGF and IGF-1, but did not affect proliferation of HSC induced by insulin. Finally, IGF-1 did not modify the activity of the Na+/Ca2+ exchanger. CONCLUSIONS: The Na+/H+ exchanger is involved in HSC proliferation induced by PDGF and IGF-1, whereas the proliferative effect of insulin is mediated by intracellular pathways which are Na+/H+ exchange-independent.


Assuntos
Hidrogênio/metabolismo , Membranas Intracelulares/metabolismo , Fígado/metabolismo , Trocadores de Sódio-Hidrogênio/metabolismo , Bicarbonatos/farmacologia , Divisão Celular/efeitos dos fármacos , Células Cultivadas , Humanos , Concentração de Íons de Hidrogênio/efeitos dos fármacos , Insulina/farmacologia , Fator de Crescimento Insulin-Like I/farmacologia , Fígado/citologia , Fator de Crescimento Derivado de Plaquetas/farmacologia
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