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1.
Am Heart J ; 163(5): 867-875.e1, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22607866

RESUMO

BACKGROUND: Diabetic patients respond less favorably to revascularization and have poorer long-term outcomes. Our main aim was to evaluate the angiographic efficacy of XIENCE V (everolimus-eluting stent, or EES) in diabetic patients compared with TAXUS Liberté (paclitaxel-eluting stent, or PES). METHODS: The SPIRIT V Diabetic Study was a prospective, single-blind, randomized study that enrolled 324 diabetic (insulin and non-insulin dependent) patients at 28 sites in Europe and Asia Pacific. Randomization was 2:1 between EES (n = 218) and PES (n = 106). The primary end point was sequential noninferiority and superiority of EES for in-stent late loss at 9 months. Secondary clinical end points included stent thrombosis, death, myocardial infarction, and revascularization rates up to 1 year. RESULTS: Everolimus-eluting stent was superior to PES for in-stent late loss at 9 months (0.19 mm vs 0.39 mm, respectively; P(superiority) = .0001). The composite rate of death, myocardial infarction, and target vessel revascularization was the same in the 2 groups at 1 year (16.3% vs 16.4%). No stent thromboses (Academic Research Consortium definite and probable) were seen through 1 year with EES compared with 2 of 104 (2%) with PES (P = .11). CONCLUSION: In this prospective, randomized trial in a high-risk group of diabetic patients, implantation of EES compared with PES resulted in significantly better inhibition of intimal hyperplasia with a comparable safety outcome.


Assuntos
Angioplastia Coronária com Balão/métodos , Doença da Artéria Coronariana/terapia , Stents Farmacológicos , Sirolimo/análogos & derivados , Taxus , Idoso , Angioplastia Coronária com Balão/mortalidade , Ásia , Angiografia Coronária , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/epidemiologia , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/epidemiologia , Angiopatias Diabéticas/diagnóstico , Angiopatias Diabéticas/epidemiologia , Angiopatias Diabéticas/terapia , Europa (Continente) , Estudos de Avaliação como Assunto , Everolimo , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Medição de Risco , Método Simples-Cego , Sirolimo/farmacologia , Estatísticas não Paramétricas , Análise de Sobrevida , Resultado do Tratamento
2.
Adv Ther ; 39(5): 2065-2084, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35287231

RESUMO

INTRODUCTION: Consensus definitions for clinical remission and super-response were recently established for severe asthma. Benralizumab is an interleukin-5 (IL-5) receptor α-directed monoclonal antibody for severe, uncontrolled asthma; efficacy and safety were demonstrated in previous pivotal phase 3 trials (SIROCCO, CALIMA, ZONDA). This analysis applied a composite remission definition to characterize individual responses to benralizumab after 6 and 12 months. METHODS: In previous phase 3 studies, eligible patients were those with severe, uncontrolled asthma receiving medium- or high-dosage inhaled corticosteroids plus long-acting ß2-agonists. This post hoc analysis included patients randomized to the approved benralizumab dose and not receiving oral corticosteroids (OCS) at baseline (SIROCCO/CALIMA) or OCS ≤ 12.5 mg per day (ZONDA). Individual remission components were zero exacerbations; zero OCS use; Asthma Control Questionnaire-6 (ACQ-6) score < 1.5 or ≤ 0.75; and pre-bronchodilator forced expiratory volume in 1 s (FEV1) increase ≥ 100 mL; clinical remission incorporated zero exacerbations, zero OCS use, ACQ-6 score ≤ 0.75, and pre-bronchodilator FEV1 increase ≥ 100 mL after 6 or 12 months. RESULTS: Overall, 609 patients (N = 301 and N = 308) and 586 patients (N = 293 and N = 293) receiving benralizumab in SIROCCO and CALIMA were included at 6 and 12 months, respectively; 40 ZONDA patients were included after 6 months. In SIROCCO/CALIMA, similar to 6-month findings, approx. 83% and approx. 49% receiving benralizumab, and 77% and 37% on placebo achieved ≥ 2 and ≥ 3 remission components after 12 months; 14.5% (85/586) on benralizumab and 7.7% (48/620) on placebo achieved clinical remission at 12 months. Among ZONDA patients, 75% and approx. 48% on benralizumab and 35% and 20% on placebo achieved ≥ 2 and ≥ 3 remission components at 6 months, respectively; 22.5% (9/40) on benralizumab and 7.5% on placebo achieved clinical remission. CONCLUSIONS: This analysis demonstrates clinical remission is achievable by targeting the underlying drivers of inflammation. Precision medicines can help shift treatment paradigms toward treat-to-target, with clinical remission as the ultimate therapeutic goal in severe asthma. CLINICAL TRIAL REGISTRATION: SIROCCO (NCT01928771); CALIMA (NCT01914757); ZONDA (NCT02075255).


Widely accepted definitions for disease remission are already established for the treatment of rheumatoid arthritis, ulcerative colitis, and cancer, among others. Two separate expert groups recently collaborated to discuss clinical remission/super-response to treatment in patients with severe asthma. Both groups developed separate, yet similar ways to determine whether a patient should be considered "in remission." In this study, we used the results from three previous trials (SIROCCO, CALIMA, and ZONDA) that were conducted to assess a therapy called benralizumab in patients with severe asthma to identify patients who met some or all of the criteria for disease remission in severe asthma. These criteria included zero asthma exacerbations; zero oral steroid (OCS) use; asthma control score; and improvement in lung function. Across all three trials, about three quarters of the patients achieved two or more remission components and about half achieved three or more remission components after 6 months of treatment; furthermore, these rates were generally similar to the numbers of patients who achieved two or more components and three or more components of remission after 12 months of treatment. Overall, 15­23% of patients achieved clinical remission in 6 months, and approximately 15% achieved remission within 12 months. The results show that biologic therapies like benralizumab help improve the symptoms of severe asthma and allow patients to achieve disease remission.


Assuntos
Antiasmáticos , Asma , Corticosteroides/uso terapêutico , Antiasmáticos/uso terapêutico , Anticorpos Monoclonais Humanizados , Asma/tratamento farmacológico , Broncodilatadores/uso terapêutico , Ensaios Clínicos Fase III como Assunto , Progressão da Doença , Método Duplo-Cego , Eosinófilos , Humanos
3.
Cell Tissue Res ; 340(3): 451-7, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20411395

RESUMO

Three different primary rat hepatocyte culture methods were compared for their ability to allow the secretion of fibrinogen and albumin under basal and IL-6-stimulated conditions. These culture methods comprised the co-culture of hepatocytes with rat liver epithelial cells (CC-RLEC), a collagen type I sandwich culture (SW) and a conventional primary hepatocyte monolayer culture (ML). Basal albumin secretion was most stable over time in SW. Fibrinogen secretion was induced by IL-6 in all cell culture models. Compared with ML, CC-RLEC showed an almost three-fold higher fibrinogen secretion under both control and IL-6-stimulated conditions. Induction of fibrinogen release by IL-6 was lowest in SW. Albumin secretion was decreased after IL-6 stimulation in both ML and CC-RLEC. Thus, cells growing under the various primary hepatocyte cell culture techniques react differently to IL-6 stimulation with regard to acute-phase protein secretion. CC-RLEC is the preferred method for studying cytokine-mediated induction of acute-phase proteins, because of the pronounced stimulation of fibrinogen secretion upon IL-6 exposure under these conditions.


Assuntos
Proteínas de Fase Aguda/metabolismo , Reação de Fase Aguda/patologia , Técnicas de Cocultura/métodos , Células Epiteliais/patologia , Hepatócitos/patologia , Interleucina-6/farmacologia , Fígado/citologia , Albuminas/metabolismo , Animais , Forma Celular/efeitos dos fármacos , Células Cultivadas , Células Epiteliais/efeitos dos fármacos , Fibrinogênio/metabolismo , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos Testes
4.
Drug Metab Rev ; 41(3): 344-90, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19601718

RESUMO

In this article, aspects of absorption, distribution, metabolism, and excretion have been described bearing in mind the pathogenesis of allergic diseases and their possible therapeutic opportunities. The importance of the routes of administration of the different therapeutic groups has been emphasized. The classical aspects of drug metabolism and disposition related to oral administration have been reviewed, but special emphasis has been given to intranasal, cutaneous, transdermal, and ocular administration as well as to the absorption and the subsequent bioavailability of drugs. Drug-metabolizing enzymes and transporters present in extrahepatic tissues, such as nasal mucosa and the respiratory tract, have been particularly discussed. As marketed antiallergic drugs include both racemates and enantiomers, aspects of stereoselective absorption, distribution, metabolism, and excretion have been discussed. Finally, a new and promising methodology, microdosing, has been presented, although it has not yet been applied to drugs used in the treatment of allergic diseases.


Assuntos
Antialérgicos/metabolismo , Antialérgicos/farmacocinética , Hipersensibilidade/tratamento farmacológico , Absorção , Animais , Antialérgicos/administração & dosagem , Antialérgicos/química , Proteínas de Transporte/metabolismo , Relação Dose-Resposta a Droga , Vias de Administração de Medicamentos , Esquema de Medicação , Humanos , Hipersensibilidade/etiologia , Hipersensibilidade/metabolismo , Inativação Metabólica , Estrutura Molecular , Especificidade de Órgãos , Estereoisomerismo , Relação Estrutura-Atividade , Distribuição Tecidual
5.
BMC Dev Biol ; 7: 24, 2007 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-17407549

RESUMO

BACKGROUND: The capability of human mesenchymal stem cells (hMSC) derived of adult bone marrow to undergo in vitro hepatic differentiation was investigated. RESULTS: Exposure of hMSC to a cocktail of hepatogenic factors [(fibroblast growth factor-4 (FGF-4), hepatocyte growth factor (HGF), insulin-transferrin-sodium-selenite (ITS) and dexamethasone)] failed to induce hepatic differentiation. Sequential exposure to these factors (FGF-4, followed by HGF, followed by HGF+ITS+dexamethasone), however, resembling the order of secretion during liver embryogenesis, induced both glycogen-storage and cytokeratin (CK)18 expression. Additional exposure of the cells to trichostatin A (TSA) considerably improved endodermal differentiation, as evidenced by acquisition of an epithelial morphology, chronological expression of hepatic proteins, including hepatocyte-nuclear factor (HNF)-3beta, alpha-fetoprotein (AFP), CK18, albumin (ALB), HNF1alpha, multidrug resistance-associated protein (MRP)2 and CCAAT-enhancer binding protein (C/EBP)alpha, and functional maturation, i.e. upregulated ALB secretion, urea production and inducible cytochrome P450 (CYP)-dependent activity. CONCLUSION: hMSC are able to undergo mesenchymal-to-epithelial transition. TSA is hereby essential to promote differentiation of hMSC towards functional hepatocyte-like cells.


Assuntos
Células da Medula Óssea/citologia , Diferenciação Celular/efeitos dos fármacos , Montagem e Desmontagem da Cromatina/efeitos dos fármacos , Hepatócitos/citologia , Ácidos Hidroxâmicos/farmacologia , Células-Tronco Mesenquimais/citologia , Acetilação , Adulto , Idoso , Idoso de 80 Anos ou mais , Técnicas de Cultura de Células , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Feminino , Histonas/metabolismo , Humanos , Imunofenotipagem , Masculino , Microscopia de Fluorescência , Pessoa de Meia-Idade , Proteína 2 Associada à Farmacorresistência Múltipla
6.
Cell Signal ; 18(5): 592-600, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16183253

RESUMO

Direct communication between cells, mediated by gap junctions, is nowadays considered as an indispensable mechanism in the maintenance of cellular homeostasis. In fact, gap junctional intercellular communication is actively involved in virtually all aspects of the cellular life cycle, ranging from cell growth to cell death. For a long time, it was believed that this was merely a result of the capacity of gap junctions to control the direct intercellular exchange of essential cellular messengers. However, recent data show that the picture is more complicated than initially thought, as structural precursors of gap junctions, connexins and gap junction hemichannels, can affect the cellular homeostatic balance independently of gap junctional intercellular communication. In this paper, we summarize the current knowledge concerning the roles of connexins and their channels in the control of cellular homeostasis, with the emphasis on cell growth and cell death. We also briefly discuss the role of gap junctional intercellular communication in carcinogenesis and the potential use of connexins as tools for cancer therapy.


Assuntos
Comunicação Celular/fisiologia , Morte Celular/fisiologia , Processos de Crescimento Celular/fisiologia , Conexinas/metabolismo , Junções Comunicantes/metabolismo , Animais , Conexinas/química , Conexinas/genética , Junções Comunicantes/química , Homeostase , Neoplasias/fisiopatologia
8.
Curr Drug Metab ; 7(6): 629-60, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16918317

RESUMO

Primary hepatocytes and their cultures are a simple but versatile, well-controlled, and relatively easy to handle in vitro system that is well-accepted for investigating xenobiotic biotransformation, enzyme induction and inhibition, and (biotransformation-mediated) hepatotoxicity. In addition, hepatocyte cultures have proven to be valuable tools in the study of liver physiology, viral hepatitis, and liver regeneration and are proposed as an alternative to orthotopic liver transplantation. It has been observed, however, that a number of liver-specific functions are progressively lost with time when hepatocytes are isolated and cultivated. These phenotypic changes are primarily the result of fundamental changes in gene expression concomitant with a diminished transcription of the relevant liver-specific genes, and can be interpreted as a 'dedifferentiation' of the isolated hepatocytes. Ischemia-reperfusion stress induced during the isolation process, disruption of the normal tissue architecture, as well as an adaptation to the in vitro environment are underlying factors and will be extensively discussed. A detailed description of the regulation of the hepatocyte phenotype in vivo in the first section of this review will help to understand the effect of these factors on hepatocyte gene expression. Although different approaches, mainly mimicking the in vivo hepatocyte environment, have been succesfully used to prevent or slow down the dedifferentiation of primary hepatocytes in monolayer culture, the ideal hepatocyte-based culture model, characterized by a long-term expression of hepatocyte-specific functions comparable to the in vivo level, does not exist at the moment. Consequently, alternative strategies should focus on the isolation procedure, during which dedifferentiation is already initiated. In addition, identification of the conditions needed for the full in vitro maturation of hepatic progenitor cells to quiescent, functional hepatocyte-like cells opens promising perspectives.


Assuntos
Diferenciação Celular , Hepatócitos/citologia , Animais , Apoptose , Comunicação Celular , Proliferação de Células , Células Cultivadas , Citocinas/biossíntese , Eicosanoides/biossíntese , Matriz Extracelular/fisiologia , Regulação da Expressão Gênica , Hepatócitos/metabolismo , Humanos , Óxido Nítrico/biossíntese , Fenótipo , Espécies Reativas de Nitrogênio , Espécies Reativas de Oxigênio
9.
Toxicol Sci ; 94(2): 330-41; discussion 235-9, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16840566

RESUMO

Differentiation of adult bone marrow stem cells (BMSC) into hepatocyte-like cells is commonly performed by continuous exposure to a cytokines-cocktail. Here, it is shown that the differentiation efficacy in vitro can be considerably enhanced by sequential addition of liver-specific factors (fibroblast growth factor-4, hepatocyte growth factor, insulin-transferrin-sodium selenite, and dexamethasone) in a time-dependent order that closely resembles the secretion pattern during in vivo liver embryogenesis. Quantitative RT-PCR analysis and immunocytochemistry showed that, upon sequential exposure to liver-specific factors, different stages of hepatocyte differentiation, as seen during liver embryogenesis, can be mimicked. Indeed, expression of the early hepatocyte markers alpha-fetoprotein and hepatocyte nuclear factor (HNF)3beta decreased as differentiation progressed, whereas levels of the late liver-specific markers albumin (ALB), cytokeratin (CK)18, and HNF1alpha were gradually upregulated. In contrast, cocktail treatment did not significantly alter the expression pattern of the hepatic markers. Moreover, sequentially exposed cells featured highly differentiated hepatic functions, including ALB secretion, glycogen storage, urea production, and inducible cytochrome P450-dependent activity, far more efficiently compared to the cocktail condition. In conclusion, sequential induction of the differentiation process, analogous to in vivo liver development, is crucial for in vitro differentiation of adult rat BMSC into functional hepatocyte-like cells. This model may not only be applicable for in vitro studies of endoderm differentiation but it also provides a "virtually unlimited" source of functional hepatocytes, suitable for preclinical pharmacological research and testing, and cell and organ development.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Citocinas/farmacologia , Desenvolvimento Embrionário/fisiologia , Células-Tronco Hematopoéticas/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Animais , Biomarcadores/metabolismo , Diferenciação Celular/fisiologia , Células Cultivadas , Glicogênio/metabolismo , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Fator 3-alfa Nuclear de Hepatócito/genética , Fator 3-alfa Nuclear de Hepatócito/metabolismo , Hepatócitos/citologia , Hepatócitos/metabolismo , Fígado/embriologia , Fígado/metabolismo , Masculino , RNA Mensageiro/metabolismo , Ratos , Ratos Endogâmicos F344 , Fatores de Tempo , Regulação para Cima , alfa-Fetoproteínas/genética , alfa-Fetoproteínas/metabolismo
10.
Toxicol Sci ; 91(2): 484-92, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16531468

RESUMO

The effects of histone deacetylase inhibitor Trichostatin A (TSA) on connexin (Cx) expression and gap junctional intercellular communication (GJIC) were investigated in primary cultures of adult rat hepatocytes. GJIC was monitored by using the scrape-loading/dye transfer method. Immunoblotting and immunocytochemistry were used to investigate Cx protein levels and localization. Cx gene expression was studied by means of quantitative reverse transcriptase-polymerase chain reaction. TSA increased Cx32 protein levels and affected negatively the Cx26 protein levels. The latter was preferentially located in the cytosol of cultured cells. TSA also promoted the appearance of Cx43 in the nuclear compartment of primary cultured hepatocytes. Overall, this resulted in enhanced GJIC activity. It is important to note that the time of onset of TSA treatment was crucial for the extent of its outcome and that the effects of TSA on Cx protein levels occurred independently of transcriptional changes. TSA differentially affects Cx proteins in primary rat hepatocyte cultures, suggesting distinct regulation and/or distinct roles of the different Cx species in the control of hepatic homeostasis. TSA enhances GJIC between primary cultured rat hepatocytes, an interesting finding supporting its use to further optimize liver-based in vitro models for pharmacotoxicological purposes.


Assuntos
Conexinas/metabolismo , Junções Comunicantes/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Inibidores de Histona Desacetilases , Ácidos Hidroxâmicos/farmacologia , Acetilação/efeitos dos fármacos , Animais , Comunicação Celular/efeitos dos fármacos , Células Cultivadas , Conexinas/genética , Junções Comunicantes/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Hepatócitos/metabolismo , Histonas/metabolismo , L-Lactato Desidrogenase/metabolismo , Masculino , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley
11.
Methods Mol Biol ; 320: 229-37, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16719394

RESUMO

In vitro models, based on liver cells or tissues, are indispensable in the early preclinical phase of drug development. An important breakthrough in establishing cell models has been the successful high-yield preparation of intact hepatocytes. In this chapter, the practical aspects of the two-step collagenase perfusion method, modified from the original procedure of Seglen, are outlined. Although applicable to the liver of various species, including human, the practical aspects of the method are explained here for rat liver. Critical parameters for the successful isolation of primary rat hepatocytes are highlighted and a troubleshooting guide is provided. In addition, a new development based on the inhibition of histone deacetylase activity is presented. This approach allows inhibition of cell-cycle reentry during hepatocyte isolation, a process known to underlie the dedifferentiation process of cultured hepatocytes.


Assuntos
Hepatócitos/citologia , Animais , Separação Celular , Colagenases/metabolismo , Fase G1 , Humanos , Masculino , Ratos , Ratos Sprague-Dawley , Fase de Repouso do Ciclo Celular
12.
Methods Mol Biol ; 320: 239-46, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16719395

RESUMO

Primary cultures of hepatocytes are useful tools for both short- and long-term pharmacotoxicological research. Under conventional conditions, isolated hepatocytes form a monolayer and survive for about 1 wk but lose some liver-specific functions, including xenobiotic biotransformation. In comparison with the conventional monolayer culture model, cocultures with rat liver epithelial cells (RLECs) have an extended lifespan and better maintain their drug-metabolizing capacity, owing to the presence of cell-cell interactions. In this chapter, techniques for setting up conventional monolayer cultures and cocultures of hepatocytes with RLECs (including isolation, culture, and cryopreservation of RLECs) are described in detail. In addition, comments derived from our own experience are given for successfully culturing primary hepatocytes.


Assuntos
Hepatócitos/efeitos dos fármacos , Animais , Biotransformação , Células Cultivadas , Técnicas de Cocultura , Hepatócitos/citologia , Hepatócitos/metabolismo , Ratos
13.
Methods Mol Biol ; 320: 247-54, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16719396

RESUMO

Mimicking the in vivo microenvironment is one of the current strategies to maintain liver-specific functionality in primary cultured hepatocytes for long periods. Freshly isolated hepatocytes entrapped in collagen gel type I (collagen gel immobilization culture) or sandwiched between two layers of hydrated collagen type I (collagen gel sandwich culture) are known to display liver-specific functions (e.g., biotransformation capacity) for more than 6 wk. We describe how to set up both types of organotypical hepatocyte culture systems. Besides a detailed protocol, we give some practical tips, taken from our own experience with long-term hepatocyte culture.


Assuntos
Colágeno/metabolismo , Hepatócitos/metabolismo , Animais , Células Cultivadas , Hepatócitos/citologia , Ratos
14.
Methods Mol Biol ; 320: 255-63, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16719397

RESUMO

Isolated hepatocytes are a physiologically relevant in vitro model exhibiting intact subcellular organelles, xenobiotic transport, and integrated phase I and phase II biotransformation. They represent the "gold standard" for investigating xenobiotic biotransformation and metabolic bioactivation. When used in suspension, they provide an easy-to-handle and relatively cheap in vitro system that can be used for up to 4 h. The use of animal- and human-derived hepatocytes allows interspecies comparisons of metabolic properties. In contrast with microsomes, which are easily prepared from human liver tissue and can be stored in liquid nitrogen with minimal loss of functionality, cryopreservation of isolated human hepatocytes has been shown to be more difficult: after thawing losses of cell viability and biotransformation capacity occur. We provide general recommendations for the appropriate use of hepatocytes in suspension for pharmaco-toxicological studies. We also provide protocols for the cryopreservation of freshly isolated hepatocytes and their handling on thawing.


Assuntos
Hepatócitos/citologia , Animais , Biotransformação , Criopreservação , Hepatócitos/efeitos dos fármacos , Humanos , Testes de Toxicidade , Xenobióticos/farmacocinética , Xenobióticos/toxicidade
15.
Curr Med Chem ; 11(12): 1629-43, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15180568

RESUMO

Modulation of chromatin structure through histone acetylation/deacetylation is known to be one of the major mechanisms involved in the regulation of gene expression. Two opposing enzyme activities determine the acetylation state of histones: histone acetyltransferases (HATs) and histone deacetylases (HDACs), respectively acetylating or deacetylating the epsilon-amino groups of lysine residues located in the amino-terminal tails of the histones. In general, transcriptionally active chromatin is associated with hyperacetylated histones, whilst silenced chromatin is linked to hypoacetylated histones. A number of structurally divergent classes of HDAC inhibitors have been identified. They have been shown to induce cell cycle arrest, terminal differentiation and/or apoptosis in various cancer cell lines and inhibit tumor growth in animals. In particular, the reversible HDAC inhibitor Trichostatin A (TSA) and its hydroxamate analogues can effectively and selectively induce tumor growth arrest at very low concentrations (nano- to micromolar range). They form a group of so-called promising antitumor agents of which some are currently under clinical trial. Since the selection of a molecule for further drug development requires a balance of biological potency, safety and pharmacokinetics, it is of paramount importance to elucidate the pharmacokinetic and toxicological properties of these HDAC inhibitors before they can be considered as potential new drugs. Primary hepatocytes and their cultures are well-differentiated in vitro models and can be used to study simultaneously the biological effects of HDAC inhibitors and their biotransformation. The present review provides a state-of-the-art of our current knowledge of the pharmacological and toxicological effects on proliferating cells of TSA and its hydroxamate-based structural analogues. Besides a theoretical basis, an overview of the experimental results, obtained by the authors using primary rat hepatocytes as an in vitro model, is given.


Assuntos
Inibidores Enzimáticos/uso terapêutico , Inibidores de Histona Desacetilases , Ácidos Hidroxâmicos/metabolismo , Ácidos Hidroxâmicos/uso terapêutico , Animais , Divisão Celular/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/toxicidade , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Humanos , Ácidos Hidroxâmicos/farmacologia , Ácidos Hidroxâmicos/toxicidade , Relação Estrutura-Atividade
16.
Invest Ophthalmol Vis Sci ; 43(3): 595-602, 2002 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11867572

RESUMO

PURPOSE: To identify in human retinoblastoma and normal retinal tissue the type of cadherin, its relationship with cytoplasmic catenins, and its participation in invasion. METHODS: The cadherin/catenin complex was characterized in surgical retinoblastoma specimens from five patients and human retinas from four donor eyes by immunocytochemistry, flow cytometry, and coimmunoprecipitation with antibodies against N-cadherin, alpha-catenin, and beta-catenin, followed by Western blot analysis or autoradiography. Y79 and WERI-Rb-1 retinoblastoma cell lines serve the evaluation of the cadherin/catenin complex in aggregation and collagen type I invasion in vitro. The association of the cadherin/catenin complex with the cytoskeleton was examined by an antibody-capping assay. RESULTS: In retinoblastoma and normal retina N-cadherin associated with alpha-catenin and beta-catenin but not E- or P-cadherin. The N-cadherin/catenin complex formed a regular, linear, and continuous honeycomb pattern in normal retina that was irregular, clustered, and interrupted in retinoblastoma. The N-cadherin/catenin complex was found also in the retinoblastoma cell lines WERI-Rb and Y79, in which it also showed an irregular pattern. Both cell lines were invasive in collagen type I, and invasion was inhibited by the GC-4 antibody, which functionally neutralizes N-cadherin. Less GC-4 antibody was needed to inhibit invasion of Y79 cells, which expressed N-cadherin at a lower level, than to inhibit invasion of WERI-Rb-1 cells. In both cell lines, antibody capping of the N-cadherin/catenin complex indicated that its linkage with the cytoskeleton were weak or absent. CONCLUSIONS: Retinoblastoma cells, in contrast with normal retina, express an N-cadherin/catenin complex that is irregularly distributed and weakly linked to the cytoskeleton. In retinoblastoma, this complex acts as an invasion promoter.


Assuntos
Caderinas/metabolismo , Proteínas do Citoesqueleto/metabolismo , Neoplasias da Retina/metabolismo , Retinoblastoma/metabolismo , Transativadores , Autorradiografia , Western Blotting , Citometria de Fluxo , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Técnicas Imunoenzimáticas , Testes de Precipitina , Retina/metabolismo , Neoplasias da Retina/patologia , Retinoblastoma/patologia , Células Tumorais Cultivadas/metabolismo , alfa Catenina , beta Catenina
17.
Altern Lab Anim ; 32 Suppl 1A: 57-64, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23577435

RESUMO

The present study shows that adult rat hepatocytes in primary culture, which normally exhibit a restricted capacity to proliferate, can proceed through the cell cycle when cultured in a mixture of minimal essential medium (MEM) and Medium 199 (MEM-M199; 3:1, v/v), containing epidermal growth factor (EGF; 50 ng/ml), low glucose (0.75 g/l) and low levels of inorganic salts, amino acids and vitamins. Under these conditions, hepatocytes flatten and cell extensions appear. In contrast, Dulbecco's modified Eagle's medium (DMEM) containing high glucose (4.5g/l) levels enriched with inorganic salts, amino acids and vitamins favours maintenance of differentiated functional hepatocyte capacities (albumin secretion), but does not allow proliferation or cell spreading. Cultivation of hepatocytes in MEM-M199 (3:1, v/v) results in the onset of DNA synthesis at 48 hours of culture and a concomitant induction of cyclin D1 protein. Under these conditions, cells successively progress through the mitogen-dependent restriction point in mid-late G1 phase, G1/S transition and S phase, as evidenced by Western blot analysis of the markers cyclins E and A and cyclin dependent kinase (CDK)2 and CDK1, respectively. Progression through the cell cycle is accompanied by a decrease in albumin secretion, indicating a decline in differentiated capacities. This study demonstrates that hepatocytes cultured in a mixture of MEM-M199 (3:1) provide a useful in vitro model for studying the regulation of hepatocyte proliferation.


Assuntos
Proliferação de Células , Meios de Cultura Livres de Soro , Fator de Crescimento Epidérmico/farmacologia , Hepatócitos/efeitos dos fármacos , Animais , Biomarcadores/metabolismo , Células Cultivadas , Replicação do DNA , Hepatócitos/citologia , Hepatócitos/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley
18.
Altern Lab Anim ; 32 Suppl 1A: 105-12, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23577441

RESUMO

This paper focuses on the use of liver-derived in vitro systems for biotransformation studies during early drug development, as exemplified by the two molecules recently studied in our laboratory: Trichostatin A (TSA) and its structural analogue 5-(4-dimethylaminobenzoyl)aminovaleric acid hydroxamide (4-Me2N-BAVAH). Phase I biotransformation of TSA, a histone deacetylase inhibitor with promising antifibrotic and antitumoural properties, was investigated in liver microsomal (rat and human) and in hepatocyte (rat) suspensions. Within 40 minutes, 50 microM of TSA was completely metabolised by 2 x 10(6) hepatocytes/ml. Reduction of the hydroxamic acid function to its corresponding amide and N-demethylation were the two major phase I biotransformation pathways, while hydrolysis products of TSA were minor metabolites. Lower concentrations of TSA (5 microM and 25 microM) were N-demethylated faster. Liver microsomes, however, metabolised TSA incompletely with the formation of two major metabolites, N-mono- and N-didemethylated TSA. Unlike TSA, 4-Me2N-BAVAH (50 microM) could still be detected after 3 hours of incubation with 2 x 10(6) rat hepatocytes/ml suspension. Hydrolysis and reduction of the hydroxamic acid function to its corresponding acid and amide, respectively, were shown to be the major phase I biotransformation pathways. Lower concentrations of 4-Me2N-BAVAH were hydrolysed more readily. 4-Me2N-BAVAH and its metabolites were less subjected to N-demethylation than TSA.


Assuntos
Hepatócitos/metabolismo , Inibidores de Histona Desacetilases/farmacocinética , Animais , Biotransformação , Cromatografia Líquida de Alta Pressão , Hepatócitos/citologia , Ácidos Hidroxâmicos/farmacocinética , Técnicas In Vitro , Masculino , Microssomos Hepáticos/metabolismo , Ratos , Ratos Sprague-Dawley , Espectrometria de Massas em Tandem
19.
EuroIntervention ; 8(3): 325-35, 2012 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-22829508

RESUMO

AIMS: SPIRIT Women is the first interventional trial dedicated exclusively to women, focusing on symptoms at presentation, referral time to coronary intervention and the safety and performance of the XIENCE V stent. METHODS AND RESULTS: SPIRIT Women is a prospective, open-label, multicentre study in which 1,573 women were enrolled at 73 sites outside the United States. The primary endpoint is the composite of all death, Academic Research Consortium (ARC) defined myocardial infarction (MI) and target vessel revascularisation (TVR) at one year. Data collected included symptoms at presentation and referral to coronary intervention. To allow comparison by gender, the latter were compared to data from male patients from the SPIRIT V study. The one- and two-year composite of all death, MI and TVR was 12% and 15%, respectively. Target lesion revascularisation (TLR) and stent thrombosis (definite and probable) rates were 2.4% and 0.59%, respectively, at one year and 3.6% and 0.73%, at two years. The total referral time for coronary intervention in women was four days longer than for men in the SPIRIT V study. CONCLUSIONS: The XIENCE V stent is safe and effective with low TLR and stent thrombosis rates. More efforts remain to be made to increase the awareness of women and physicians of the risk for coronary artery disease (CAD).


Assuntos
Angioplastia Coronária com Balão , Doença da Artéria Coronariana/terapia , Stents Farmacológicos , Sirolimo/análogos & derivados , Adolescente , Adulto , Idoso , Angioplastia Coronária com Balão/efeitos adversos , Doença da Artéria Coronariana/etiologia , Reestenose Coronária , Stents Farmacológicos/efeitos adversos , Everolimo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Encaminhamento e Consulta/estatística & dados numéricos , Fatores de Risco , Sirolimo/administração & dosagem , Fatores de Tempo , Resultado do Tratamento
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