Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Diabetes Obes Metab ; 18 Suppl 1: 144-51, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27615144

RESUMO

Creating an abundant source of ß(-like)-cells has been a major goal in diabetes research for many decades. The concept of cell plasticity has inspired many strategies towards regenerative medicine, but its successes have been limited until very recently. Today, most cell types in the pancreas are considered candidates for the generation of ß(-like)-cells through transdifferentiation. While ß(-like)-cells that are in vitro differentiated from human embryonic stem cells are already being grafted in patients, ß(-like)-cells generated by transdifferentiation are not yet ready for clinical application. These cells would however offer several advantages over the current ß(-like)-cells generated by directed differentiation, especially concerning safety issues. In addition, perfect control of the transdifferentiation efficiency would through targeted drug delivery support a non-invasive cell therapy for diabetes. Lastly, focusing on the exocrine pancreas as prime candidate makes sense in view of their abundance and high plasticity. Keeping these hopeful perspectives in mind, it is worth to continue focused research on the mechanisms that control transdifferentiation from pancreas exocrine to ß-cells.


Assuntos
Plasticidade Celular , Transdiferenciação Celular , Técnicas de Reprogramação Celular/métodos , Diabetes Mellitus/terapia , Células Secretoras de Insulina/citologia , Pâncreas Exócrino/citologia , Terapia Baseada em Transplante de Células e Tecidos/métodos , Humanos , Células Secretoras de Insulina/transplante
2.
Cell Death Dis ; 7(6): e2272, 2016 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-27336716

RESUMO

Partial pancreatic duct ligation (PDL) of mouse pancreas induces a doubling of the ß-cell mass mainly through proliferation of pre-existing and newly formed ß-cells. The molecular mechanism governing this process is still largely unknown. Given the inflammatory nature of PDL and inflammation-induced signaling via the signal transducer and activator of transcription 3 (STAT3), the activation and the role of STAT3 in PDL-induced ß-cell proliferation were investigated. Duct ligation stimulates the expression of several cytokines that can act as ligands inducing STAT3 signaling and phosphorylation in ß-cells. ß-Cell cycling increased by conditional ß-cell-specific Stat3 knockout and decreased by STAT3 activation through administration of interleukin-6. In addition, the level of DNA damage in ß-cells of PDL pancreas increased after deletion of Stat3. These data indicate a role for STAT3 in maintaining a steady state in the ß-cell, by modulating its cell cycle and protection from DNA damage.


Assuntos
Ciclo Celular , Citoproteção , Dano ao DNA , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patologia , Fator de Transcrição STAT3/metabolismo , Animais , Ciclo Celular/efeitos dos fármacos , Citocinas/metabolismo , Citoproteção/efeitos dos fármacos , Células Secretoras de Insulina/efeitos dos fármacos , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Interleucina-6/farmacologia , Antígeno Ki-67/metabolismo , Ligadura , Masculino , Camundongos Endogâmicos BALB C , Camundongos Knockout , Ductos Pancreáticos/efeitos dos fármacos , Ductos Pancreáticos/patologia , Proteínas Recombinantes/farmacologia
3.
Diabetes Obes Metab ; 18(2): 115-24, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26289770

RESUMO

Despite recent advances, insulin therapy remains a treatment, not a cure, for diabetes mellitus with persistent risk of glycaemic alterations and life-threatening complications. Restoration of the endogenous ß-cell mass through regeneration or transplantation offers an attractive alternative. Unfortunately, signals that drive ß-cell regeneration remain enigmatic and ß-cell replacement therapy still faces major hurdles that prevent its widespread application. Co-transplantation of accessory non-islet cells with islet cells has been shown to improve the outcome of experimental islet transplantation. This review will highlight current travails in ß-cell therapy and focuses on the potential benefits of accessory cells for islet transplantation in diabetes.


Assuntos
Diabetes Mellitus Tipo 1/cirurgia , Sobrevivência de Enxerto , Tolerância Imunológica , Células Secretoras de Insulina/transplante , Transplante de Células-Tronco/efeitos adversos , Transplante Heterotópico , Animais , Proliferação de Células , Separação Celular/tendências , Células Cultivadas , Diabetes Mellitus Tipo 1/imunologia , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/patologia , Diabetes Mellitus Tipo 2/imunologia , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patologia , Diabetes Mellitus Tipo 2/cirurgia , Células Progenitoras Endoteliais/citologia , Células Progenitoras Endoteliais/imunologia , Células Progenitoras Endoteliais/patologia , Células Progenitoras Endoteliais/transplante , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/metabolismo , Rejeição de Enxerto/prevenção & controle , Humanos , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/imunologia , Células Secretoras de Insulina/metabolismo , Transplante das Ilhotas Pancreáticas/efeitos adversos , Transplante das Ilhotas Pancreáticas/imunologia , Transplante de Células-Tronco Mesenquimais/efeitos adversos , Transplante de Células-Tronco Mesenquimais/tendências , Crista Neural/citologia , Crista Neural/imunologia , Crista Neural/patologia , Crista Neural/transplante , Transplante de Células-Tronco/tendências , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/patologia , Linfócitos T Reguladores/transplante , Transplante Autólogo/efeitos adversos , Transplante Autólogo/tendências , Transplante Heterotópico/efeitos adversos , Transplante Heterotópico/tendências , Transplante Homólogo/efeitos adversos , Transplante Homólogo/tendências
4.
Cell Death Differ ; 22(7): 1117-30, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25476775

RESUMO

Rodent acinar cells exhibit a remarkable plasticity as they can transdifferentiate to duct-, hepatocyte- and islet ß-like cells. We evaluated whether exocrine cells from adult human pancreas can similarly respond to proendocrine stimuli. Exocrine cells from adult human pancreas were transduced directly with lentiviruses expressing activated MAPK (mitogen-activated protein kinase) and STAT3 (signal transducer and activator of transcription 3) and cultured as monolayers or as 3D structures. Expression of STAT3 and MAPK in human exocrine cells activated expression of the proendocrine factor neurogenin 3 in 50% to 80% of transduced exocrine cells. However, the number of insulin-positive cells increased only in the exocrine cells grown initially in suspension before 3D culture. Lineage tracing identified human acinar cells as the source of Ngn3- and insulin-expressing cells. Long-term engraftment into immunocompromised mice increased the efficiency of reprogramming to insulin-positive cells. Our data demonstrate that exocrine cells from human pancreas can be reprogrammed to transplantable insulin-producing cells that acquire functionality. Given the large number of exocrine cells in a donor pancreas, this approach presents a novel strategy to expand cell therapy in type 1 diabetes.


Assuntos
Transdiferenciação Celular/genética , Transplante de Células , Células Secretoras de Insulina/metabolismo , Proteínas Quinases Ativadas por Mitógeno/genética , Pâncreas Exócrino/citologia , Pâncreas Exócrino/metabolismo , Fator de Transcrição STAT3/genética , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Humanos , Células Secretoras de Insulina/transplante , Camundongos , Proteínas do Tecido Nervoso , Transdução Genética , Regulação para Cima
5.
Cell Death Dis ; 4: e523, 2013 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-23470530

RESUMO

We previously showed that injury by partial duct ligation (PDL) in adult mouse pancreas activates Neurogenin 3 (Ngn3)(+) progenitor cells that can differentiate to ß cells ex vivo. Here we evaluate the role of Ngn3(+) cells in ß cell expansion in situ. PDL not only induced doubling of the ß cell volume but also increased the total number of islets. ß cells proliferated without extended delay (the so-called 'refractory' period), their proliferation potential was highest in small islets, and 86% of the ß cell expansion was attributable to proliferation of pre-existing ß cells. At sufficiently high Ngn3 expression level, upto 14% of all ß cells and 40% of small islet ß cells derived from non-ß cells. Moreover, ß cell proliferation was blunted by a selective ablation of Ngn3(+) cells but not by conditional knockout of Ngn3 in pre-existing ß cells supporting a key role for Ngn3(+) insulin(-) cells in ß cell proliferation and expansion. We conclude that Ngn3(+) cell-dependent proliferation of pre-existing and newly-formed ß cells as well as reprogramming of non-ß cells contribute to in vivo ß cell expansion in the injured pancreas of adult mice.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Células Secretoras de Insulina/fisiologia , Proteínas do Tecido Nervoso/metabolismo , Pâncreas/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Proliferação de Células , Tamanho Celular , Insulina/metabolismo , Células Secretoras de Insulina/citologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Proteínas do Tecido Nervoso/genética , Pâncreas/lesões , Pâncreas/patologia , Regeneração
6.
Diabetologia ; 56(2): 382-90, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23090187

RESUMO

AIMS/HYPOTHESIS: As current islet-transplantation protocols suffer from significant graft loss and dysfunction, strategies to sustain the long-term benefits of this therapy are required. Rapid and adequate oxygen and nutrient delivery by blood vessels improves islet engraftment and function. The present report evaluated a potentially beneficial effect of adult human blood outgrowth endothelial cells (BOEC) on islet graft vascularisation and function. METHODS: Human BOEC, 5 × 10(5), were co-transplanted with a rat marginal-islet graft under the kidney capsule of hyperglycaemic NOD severe combined immunodeficiency (SCID) mice, and the effect on metabolic outcome was evaluated. RESULTS: Although vessel density remained unaffected, co-transplantation of islets with BOEC resulted in a significant and specific improvement of glycaemia and increased plasma C-peptide. Moreover, in contrast to control mice, BOEC recipients displayed reduced beta cell death and increases in body weight, beta cell proliferation and graft-vessel and beta cell volume. In vivo cell tracing demonstrated that BOEC remain at the site of transplantation and do not expand. The potential clinical applicability was underscored by the observed metabolic benefit of co-transplanting islets with BOEC derived from a type 1 diabetes patient. CONCLUSIONS/INTERPRETATION: The present data support the use of autologous BOEC in translational studies that aim to improve current islet-transplantation protocols for the treatment of brittle type 1 diabetes.


Assuntos
Células Endoteliais/transplante , Transplante das Ilhotas Pancreáticas/métodos , Animais , Células Cultivadas , Diabetes Mellitus Tipo 1/terapia , Humanos , Masculino , Camundongos , Camundongos SCID
7.
Diabetologia ; 55(7): 2016-25, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22618811

RESUMO

AIMS/HYPOTHESIS: Efficient stimulation of cycling activity in cultured beta cells would allow the design of new strategies for cell therapy in diabetes. Neural crest stem cells (NCSCs) play a role in beta cell development and maturation and increase the beta cell number in co-transplants. The mechanism behind NCSC-induced beta cell proliferation and the functional capacity of the new beta cells is not known. METHODS: We developed a new in vitro co-culture system that enables the dissection of the elements that control the cellular interactions that lead to NCSC-dependent increase in islet beta cells. RESULTS: Mouse NCSCs were cultured in vitro, first in medium that stimulated their proliferation, then under conditions that supported their differentiation. When mouse islet cells were cultured together with the NCSCs, more than 35% of the beta cells showed cycle activity. This labelling index is more than tenfold higher than control islets cultured without NCSCs. Beta cells that proliferated under these culture conditions were fully glucose responsive in terms of insulin secretion. NCSCs also induced beta cell proliferation in islets isolated from 1-year-old mice, but not in dissociated islet cells isolated from human donor pancreas tissue. To stimulate beta cell proliferation, NCSCs need to be in intimate contact with the beta cells. CONCLUSIONS/INTERPRETATION: Culture of islet cells in contact with NCSCs induces highly efficient beta cell proliferation. The reported culture system is an excellent platform for further dissection of the minimal set of factors needed to drive this process and explore its potential for translation to diabetes therapy.


Assuntos
Glicemia/metabolismo , Desoxiuridina/farmacologia , Diabetes Mellitus Experimental/metabolismo , Transplante das Ilhotas Pancreáticas/métodos , Ilhotas Pancreáticas/metabolismo , Crista Neural/citologia , Animais , Proliferação de Células , Células Cultivadas , Técnicas de Cocultura , Diabetes Mellitus Experimental/terapia , Transplante das Ilhotas Pancreáticas/tendências , Camundongos , Camundongos Endogâmicos C57BL
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...