Water-soluble polymers poly(ethylene glycol) (PEG) and poly(N-vinylpyrrolidone) (PVP) were used to study cryopreservation of porcine islets. DMSO was used as control. The effects of polymer purity, molecular weight (M...Water-soluble polymers poly(ethylene glycol) (PEG) and poly(N-vinylpyrrolidone) (PVP) were used to study cryopreservation of porcine islets. DMSO was used as control. The effects of polymer purity, molecular weight (MW) and concentration on islet viability were investigated. The results show that both PVP and PEG are good cyroprotectant candidates for islet cryopreservation. The effects of polymer purity and concentration were significant. Increasing concentration significantly increased the islet viability. However, after the concentration reached a certain level, there was no significant difference in viability probably due to increased viscosity of the polymer solution. The effect of polymer MW was not significant. It is concluded that polymers can be a suitable cryoprotectant for porcine islet cryopreservation. The islet viability is polymer concentration-dependent. It seems that PVP is a better cryoprotectant candidate as compared to PEG because the former showed a fast dissolution rate in culture medium and lower viscosity. The polymer concentration at 30% appears to be the optimal for cryopreservation from the viewpoint of islet viability and medium viscosity.展开更多
BACKGROUND: A major barrier to the clinical application of xenotransplantation as a treatment option for patients is T cell-mediated rejection. Studies based on experimental rodent models of xenograft tolerance or rej...BACKGROUND: A major barrier to the clinical application of xenotransplantation as a treatment option for patients is T cell-mediated rejection. Studies based on experimental rodent models of xenograft tolerance or rejection in vivo have provided useful information about the role of T cell immune response in xenotransplantation. However not all observations seen in rodents faithfully recapitulate the human situation This study aimed to establish a humanized mouse model of xenotransplantation, which mimics xenograft rejection in the context of the human immune system. METHODS: NOD-SCID IL2rγ -/- mice were transplanted with neonatal porcine islet cell clusters (NICC) followed by reconstitution of human peripheral blood mononuclear cells (PBMC). Human leukocyte engraftment and islet xenograft rejection were confirmed by flow cytometric and histological analyses. RESULTS: In the absence of human PBMC, porcine NICC transplanted into NOD-SCID IL2rγ -/- mice revealed excellent graft integrity and endocrine function. Human PBMC demonstrated a high level of engraftment in NOD-SCID IL2rγ -/- mice. Reconstitution of NICC recipient NOD-SCID IL2rγ -/- mice with human PBMC led to the rapid destruction of NICC xenografts in a PBMC number-dependent manner. CONCLUSIONS: Human PBMC-reconstituted NOD-SCID IL2rγ -/- mice provide an ideal model to study human immune responses in xenotransplantation. Studies based on this humanized mouse model will provide insight for improving the outcomes of clinical xenotransplantation.展开更多
文摘Water-soluble polymers poly(ethylene glycol) (PEG) and poly(N-vinylpyrrolidone) (PVP) were used to study cryopreservation of porcine islets. DMSO was used as control. The effects of polymer purity, molecular weight (MW) and concentration on islet viability were investigated. The results show that both PVP and PEG are good cyroprotectant candidates for islet cryopreservation. The effects of polymer purity and concentration were significant. Increasing concentration significantly increased the islet viability. However, after the concentration reached a certain level, there was no significant difference in viability probably due to increased viscosity of the polymer solution. The effect of polymer MW was not significant. It is concluded that polymers can be a suitable cryoprotectant for porcine islet cryopreservation. The islet viability is polymer concentration-dependent. It seems that PVP is a better cryoprotectant candidate as compared to PEG because the former showed a fast dissolution rate in culture medium and lower viscosity. The polymer concentration at 30% appears to be the optimal for cryopreservation from the viewpoint of islet viability and medium viscosity.
基金supported by grants from the National Health and Medical Research Council of Australiathe National Natural Science Foundation of China(81271712)Hunan Provincial Natural Science Foundation of China(11JJ4078)
文摘BACKGROUND: A major barrier to the clinical application of xenotransplantation as a treatment option for patients is T cell-mediated rejection. Studies based on experimental rodent models of xenograft tolerance or rejection in vivo have provided useful information about the role of T cell immune response in xenotransplantation. However not all observations seen in rodents faithfully recapitulate the human situation This study aimed to establish a humanized mouse model of xenotransplantation, which mimics xenograft rejection in the context of the human immune system. METHODS: NOD-SCID IL2rγ -/- mice were transplanted with neonatal porcine islet cell clusters (NICC) followed by reconstitution of human peripheral blood mononuclear cells (PBMC). Human leukocyte engraftment and islet xenograft rejection were confirmed by flow cytometric and histological analyses. RESULTS: In the absence of human PBMC, porcine NICC transplanted into NOD-SCID IL2rγ -/- mice revealed excellent graft integrity and endocrine function. Human PBMC demonstrated a high level of engraftment in NOD-SCID IL2rγ -/- mice. Reconstitution of NICC recipient NOD-SCID IL2rγ -/- mice with human PBMC led to the rapid destruction of NICC xenografts in a PBMC number-dependent manner. CONCLUSIONS: Human PBMC-reconstituted NOD-SCID IL2rγ -/- mice provide an ideal model to study human immune responses in xenotransplantation. Studies based on this humanized mouse model will provide insight for improving the outcomes of clinical xenotransplantation.
