Made available in DSpace on 2014-06-11T19:32:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-03-17Bitstream added on 2014-06-13T19:43:01Z : No. of bitstreams: 1 penteado_fcl_dr_arafcf.pdf: 1008387 bytes, checksum: 40b22d48514b2c755f67d69d9ae8cff6 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Alguns trabalhos realizados recentemente relatam que as células-tronco mesenquimais (CTM) podem ser induzidas à aquisição de marcadores hepatocíticos pelo transplante em modelos animais de dano hepático, ou pelo cultivo in vitro com fatores de crescimento e citocinas. O presente trabalho teve por objetivo avaliar o comportamento das CTM frente à indução da diferenciação hepatocítica. As CTM foram isoladas da medula óssea de quatro doadores saudáveis, caracterizadas e submetidas ao protocolo de indução à diferenciação hepatocítica in vitro e in vivo. As células induzidas in vitro apresentaram mudanças na sua morfologia, mostrando a morfologia semelhante à do hepatócito, porém, o perfil imunofenotípico não foi modificado. As células induzidas também não apresentaram o aumento dos transcritos de albumina, citoqueratina 18 e citoqueratina 19 quando analisadas por RT-PCR em tempo real, e não alteraram a expressão de albumina, citoqueratina 18 e alfafetoproteína como demonstrado por imunofluorescência. Quando analisadas in vivo, as CTM demonstraram o potencial migratório para o tecido hepático danificado de camundongos imunodeficientes. Em conjunto, os resultados sugerem que as CTM da medula óssea não são capazes de se diferenciar em hepatócitos quando estimuladas in vitro pela metodologia utilizado neste trabalho, mas são capazes de migrar para o tecido hepático danificado in vivo, o que sugere o seu papel no reparo do fígado. A contribuição para o reparo pode estar associada com o efeito parácrino dessas células. / Some recently works have been reported that mesenchymal stem cells (MSC) can be induced to the acquisition of hepatocytic markers for the transplant in animal models of liver damage, or for the in vitro culture with growth factors and cytokines. The present work aim is to evaluate the behavior of the MSC in front of the induction of the hepatocytic differentiation. The MSC was isolated from the bone morrow of 4 normal donators, characterized and submitted to the protocol of in vitro and in vivo induction of hepatocytic differentiation. The in vitro induced cells showed morphology changes acquiring hepatocytes-like morphology. However, the immunophenotypic profile of those cells was not modified. The induced cells did not present increase of the albumin, cytokeratin 18 and cytokeratin 19 transcripts, when analyzed by real time RTPCR. The expression of albumin, cytokeratin 18 and alpha foetoprotein was also not modified as demonstrated by immunofluorescence. In vivo, the MSC have demonstrated the migratory potential for the damaged liver of immunodeficient mice. Together, the results suggest that the bone morrow MSC are not capable of in vitro hepatocytic differentiating according to the approach in this work, but are capable to homming into damaged hepatic tissue in vivo. This migration capacity suggests their role in the repair mechanisms.

Orientador: Dimas Tadeu Covas / Banca: José Orlando Bordin / Banca: Carmino Antônio de Souza / Banca: Orlando Castro e Silva Júnior / Banca: Aparecida Maria Fontes / Resumo: Alguns trabalhos realizados recentemente relatam que as células-tronco mesenquimais (CTM) podem ser induzidas à aquisição de marcadores hepatocíticos pelo transplante em modelos animais de dano hepático, ou pelo cultivo in vitro com fatores de crescimento e citocinas. O presente trabalho teve por objetivo avaliar o comportamento das CTM frente à indução da diferenciação hepatocítica. As CTM foram isoladas da medula óssea de quatro doadores saudáveis, caracterizadas e submetidas ao protocolo de indução à diferenciação hepatocítica in vitro e in vivo. As células induzidas in vitro apresentaram mudanças na sua morfologia, mostrando a morfologia semelhante à do hepatócito, porém, o perfil imunofenotípico não foi modificado. As células induzidas também não apresentaram o aumento dos transcritos de albumina, citoqueratina 18 e citoqueratina 19 quando analisadas por RT-PCR em tempo real, e não alteraram a expressão de albumina, citoqueratina 18 e alfafetoproteína como demonstrado por imunofluorescência. Quando analisadas in vivo, as CTM demonstraram o potencial migratório para o tecido hepático danificado de camundongos imunodeficientes. Em conjunto, os resultados sugerem que as CTM da medula óssea não são capazes de se diferenciar em hepatócitos quando estimuladas in vitro pela metodologia utilizado neste trabalho, mas são capazes de migrar para o tecido hepático danificado in vivo, o que sugere o seu papel no reparo do fígado. A contribuição para o reparo pode estar associada com o efeito parácrino dessas células. / Abstract: Some recently works have been reported that mesenchymal stem cells (MSC) can be induced to the acquisition of hepatocytic markers for the transplant in animal models of liver damage, or for the in vitro culture with growth factors and cytokines. The present work aim is to evaluate the behavior of the MSC in front of the induction of the hepatocytic differentiation. The MSC was isolated from the bone morrow of 4 normal donators, characterized and submitted to the protocol of in vitro and in vivo induction of hepatocytic differentiation. The in vitro induced cells showed morphology changes acquiring hepatocytes-like morphology. However, the immunophenotypic profile of those cells was not modified. The induced cells did not present increase of the albumin, cytokeratin 18 and cytokeratin 19 transcripts, when analyzed by real time RTPCR. The expression of albumin, cytokeratin 18 and alpha foetoprotein was also not modified as demonstrated by immunofluorescence. In vivo, the MSC have demonstrated the migratory potential for the damaged liver of immunodeficient mice. Together, the results suggest that the bone morrow MSC are not capable of in vitro hepatocytic differentiating according to the approach in this work, but are capable to homming into damaged hepatic tissue in vivo. This migration capacity suggests their role in the repair mechanisms. / Doutor

Background: The beneficial impact of mesenchymal stem cells (MSC) on both acute and chronic liver diseases has been confirmed, although the molecular mechanisms behind it remain elusive. We aim to identify factors secreted by undifferentiated and hepatocytic differentiated MSC in vitro in order to delineate liver repair pathways potentially targeted by MSC. Methods: Secreted factors were determined by protein arrays and related pathways identified by biomathematical analyses. Results: MSC from adipose tissue and bone marrow expressed a similar pattern of surface markers. After hepatocytic differentiation, CD54 (intercellular adhesion molecule 1, ICAM-1) increased and CD166 (activated leukocyte cell adhesion molecule, ALCAM) decreased. MSC secreted different factors before and after differentiation. These comprised cytokines involved in innate immunity and growth factors regulating liver regeneration. Pathway analysis revealed cytokine-cytokine receptor interactions, chemokine signalling pathways, the complement and coagulation cascades as well as the Januskinase-signal transducers and activators of transcription (JAK-STAT) and nucleotide-binding oligomerization domain-like receptor (NOD-like receptor) signalling pathways as relevant networks. Relationships to transforming growth factor beta(TGF-beta) and hypoxia-inducible factor 1-alpha (HIF1-alpha) signalling seemed also relevant. Conclusion: MSC secreted proteins, which differed depending on cell source and degree of differentiation. The factors might address inflammatory and growth factor pathways as well as chemo-attraction and innate immunity. Since these are prone to dysregulation in most liver diseases, MSC release hepatotropic factors, potentially supporting liver regeneration.

Background: The beneficial impact of mesenchymal stem cells (MSC) on both acute and chronic liver diseases has been confirmed, although the molecular mechanisms behind it remain elusive. We aim to identify factors secreted by undifferentiated and hepatocytic differentiated MSC in vitro in order to delineate liver repair pathways potentially targeted by MSC. Methods: Secreted factors were determined by protein arrays and related pathways identified by biomathematical analyses. Results: MSC from adipose tissue and bone marrow expressed a similar pattern of surface markers. After hepatocytic differentiation, CD54 (intercellular adhesion molecule 1, ICAM-1) increased and CD166 (activated leukocyte cell adhesion molecule, ALCAM) decreased. MSC secreted different factors before and after differentiation. These comprised cytokines involved in innate immunity and growth factors regulating liver regeneration. Pathway analysis revealed cytokine-cytokine receptor interactions, chemokine signalling pathways, the complement and coagulation cascades as well as the Januskinase-signal transducers and activators of transcription (JAK-STAT) and nucleotide-binding oligomerization domain-like receptor (NOD-like receptor) signalling pathways as relevant networks. Relationships to transforming growth factor beta(TGF-beta) and hypoxia-inducible factor 1-alpha (HIF1-alpha) signalling seemed also relevant. Conclusion: MSC secreted proteins, which differed depending on cell source and degree of differentiation. The factors might address inflammatory and growth factor pathways as well as chemo-attraction and innate immunity. Since these are prone to dysregulation in most liver diseases, MSC release hepatotropic factors, potentially supporting liver regeneration.