RESUMO
The macrophage derived cytokines interleukin-beta (IL-1beta), and tumor necrosis factor alpha (TNFalpha), and the T-cell derived cytokine interferon gamma (IFNgamma) have been implicated to play an important role in early attack on islet cells during human islet transplantation (ITx). Therefore, the aim of this study was to investigate the influence of the current immunosuppressive induction therapy in clinical islet transplantation on mRNA expression of these cytokines in blood cells, compared to lipopolysaccharide (LPS) induced cytokine release in vitro and to plasma levels. The cytokine release correlated to lymphocyte counts and significantly decreased after ATG, and partially recovered 2 weeks after ITx. Unexpectedly, there was no correlation between mRNA expression for IL-1beta in total blood and the number of lymphocytes and monocytes remaining after anti thymocyte globulin (ATG)-therapy. Even when the blood was nearly totally depleted from mononuclear cells, high amounts of IL-1beta mRNA could be detected. However, IL-1beta secretion could not be stimulated in vitro. Our results show that application of ATG during ITx might contribute to graft survival during the early posttransplant period by suppression of the synthesis of monocyte derived cytokines IL-1beta and TNFalpha.
Assuntos
Soro Antilinfocitário/uso terapêutico , Citocinas/biossíntese , Imunossupressores/uso terapêutico , Transplante das Ilhotas Pancreáticas/imunologia , Citocinas/genética , Sobrevivência de Enxerto , Humanos , Interferon gama/biossíntese , Interferon gama/genética , Interleucina-1/biossíntese , Interleucina-1/genética , Transplante de Rim/imunologia , Contagem de Linfócitos , Linfócitos/imunologia , Monócitos/imunologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Fator de Necrose Tumoral alfa/biossíntese , Fator de Necrose Tumoral alfa/genéticaRESUMO
Highly purified porcine islets were prepared by isokinetic gradients performed subsequently to isopycnic gradients. This additional purification step separates ductal, vascular, and lymphoid tissue effectively from endocrine tissue. Although ductal, vascular, and lymphoid tissue comprises only a minor contamination of the islet suspensions, a significant prolongation of the survival of porcine islets xenografted into streptozotocin diabetic C57BL/6 mice can be achieved by the elimination of the non-endocrine tissue. Rejection after islet transplantation is delayed from 2.2+/-0.4 days (n=27) to 13.1+/-2.1 days (n=36), respectively, when conventionally purified and highly purified islets are compared. Irrespective of the purification state, pretreatment of islets by low temperature culture had no effect on xenograft survival.
Assuntos
Sobrevivência de Enxerto , Transplante das Ilhotas Pancreáticas , Ilhotas Pancreáticas/citologia , Transplante Heterólogo , Animais , Separação Celular/métodos , Células Cultivadas , Centrifugação Isopícnica , Diabetes Mellitus Experimental/cirurgia , Ilhotas Pancreáticas/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Suínos , TemperaturaAssuntos
Citocinas/biossíntese , Imunossupressores/uso terapêutico , Transplante das Ilhotas Pancreáticas/imunologia , Linfócitos/imunologia , Monócitos/imunologia , Transcrição Gênica/efeitos dos fármacos , Soro Antilinfocitário/uso terapêutico , Células Cultivadas , Humanos , Interferon gama/biossíntese , Interleucina-1/biossíntese , Lipopolissacarídeos/farmacologia , Linfócitos/efeitos dos fármacos , Monócitos/efeitos dos fármacos , RNA Mensageiro/biossíntese , Transplante Homólogo , Fator de Necrose Tumoral alfa/biossínteseRESUMO
Prevention of the occurrence of diabetes-specific vascular complications is the final aim of clinical islet transplantation. Pancreatic islets isolated from adult pigs may be a suitable tissue source to transplant a large number of type 1 diabetic patients. Acute cellular rejection may be finally overcome by clinically applicable protocols for tolerance induction. However, primary nonfunction of the graft, as regularly observed in the porcine islet-to-rat xenotransplantation model, may be an additional problem. In this paper, species-specific inflammatory and immunological mechanisms are discussed which prevent early porcine islet graft function in rats but not in mice.