ABSTRACT
Objective To investigate the isolation and culture of porcine bone marrow mesenchymal stem cell (BMSC) with α-1, 3-galactosyltransferase (GGTA1) gene knockout (GTKO), GTKO/ human CD46 (hCD46) insertion and cytidine monopho-N-acetylneuraminic acid hydroxylase (CMAH)/GGTA1 gene knockout (Neu5GC/Gal), and the protective effect of co-culture with porcine islets on islet cells. Methods Bone marrow was extracted from different transgenic pigs modified with GTKO, GTKO/hCD46 and Neu5GC/Gal. Porcine BMSC were isolated by the whole bone marrow adherent method and then cultured. The morphology of BMSC was observed and the surface markers of BMSC were identified by flow cytometry. Meantime, the multi-directional differentiation induced by BMSC was observed, and the labeling and tracing of BMSC were realized by green fluorescent protein (GFP) transfection. The porcine BMSC transfected with GFP were co-cultured with porcine islet cells. Morphological changes of porcine islet cells were observed, and compared with those in the porcine islet cell alone culture group. Results BMSC derived from pigs were spindle-shaped in vitro, expressing biomarkers of CD29, CD44, CD73, CD90, CD105 and CD166 rather than CD34 and CD45. These cells were able to differentiate into adipocytes, osteoblasts and chondrocytes. Porcine BMSC with GFP transfection could be labeled and traced, which could be stably expressed in the daughter cells after cell division. Porcine BMSC exerted certain protective effect on islet cells. Conclusions GFP-labeled porcine BMSC modified with GTKO, GTKO/hCD46 and Neu5GC/Gal are successfully established, which exert certain protective effect upon islet cells.
ABSTRACT
Objective To investigate the effect of human CD47 (hCD47) in inducing the immune tolerance of human macrophages to porcine endothelial cells. Methods The porcine iliac endothelial cell (PIEC) transfected with pCDH-hCD47-FLAG plasmid was assigned into the pCDH-hCD47 group, PIEC transfected with pCDH-FLAG empty vector plasmid was assigned into the pCDH group, PIEC transfected with hCD47-dN was assigned into the pCDH-hCD47-dN group and human umbilical vein endothelial cell (HUVEC) was assigned into the positive control group. The cells were co-cultured with human macrophages to detect and analyze the phosphorylation of signal regulatory protein α (SIRPα) and the killing effect of human macrophages on PIEC. Furthermore, porcine arteriae endothelial cell (PAEC) was isolated from GT－/－ and GT－/－/ hCD 47 gene editing pigs to analyze the phosphorylation of SIRPα and the killing effect of human macrophages on PAEC. Results The pCDH group cells could not induce the phosphorylation of SIRPα, whereas the pCDH-hCD47 group cells could activate the phosphorylation of SIRPα after 10 min co-culture with human macrophages, and the degree of phosphorylation of SIRPα was increased with the prolongation of the co-culture time. The pCDH-hCD47-dN group cells failed to activate the phosphorylation of SIRPα. Human macrophages exerted significant effect on killing the pCDH group cells. The pCDH-hCD47 group cells could evidently inhibit the killing effect of human macrophages (P < 0.05), whereas the pCDH-hCD47-dN cells failed to suppress the killing effect of human macrophages. GT－/－-PAEC could not activate the phosphorylation of SIRPα after co-culture with human macrophages. However, GT－/－/hCD47-PAEC significantly activated the phosphorylation of SIRPα after co-culture with human macrophages. Human macrophages exerted significant killing effect on GT－/－-PAEC, and GT－/－/hCD47-PAEC could obviously inhibit the killing effect of human macrophages (P < 0.05). Conclusions The expression of hCD47 in the porcine endothelial cells can inhibit the killing effect of human macrophages on endothelial cells by activating the phosphorylation of SIRPα.
ABSTRACT
Objective To compare the effect of transplant islets between the subcutaneous inguinal white adipose tissues and renal capsule in the treatment of type 1 diabetes mellitus in mouse models. Methods The mice with type 1 diabetes mellitus undergoing islet transplantation were divided into the white adipose group (n=10) and renal capsule group (n=10). The islets were isolated, purified and transplanted to the subcutaneous white adipose tissues of inguinal region and renal capsule. The random blood glucose level and glucose tolerance function of the recipient mice in two groups were continuously monitored after operation. Islet grafts of the surviving recipient mice were harvested at postoperative 100 d for histopathological examination. Results In the white adipose group, the blood glucose levels of 6 recipient mice were restored to normal at 1 month after transplantation, whereas the blood glucose levels of the other 4 recipient mice were high, which died before the end of monitoring. In the renal capsule group, the blood glucose levels of 10 recipient mice returned to normal within 10 d after transplantation. Islet grafts of the recipient mice in two groups could lower the blood glucose levels, whereas the islet grafts in the white adipose group required a longer time to exert the effect. The glucose tolerance function of the mice in the renal capsule group was significantly better than that of those in white adipose group (P < 0.05). Histopathological examination demonstrated that the insulin of the islet grafts was normally expressed in two groups. Conclusions The islets transplanted into the subcutaneous white adipose tissues of inguinal region can play an effective role in regulating the changes of blood glucose level. Although the blood glucose-lowering function is slightly weaker than that of the islets graft in the renal capsule, it has multiple advantages resembling the ideal islet transplantation sites, which is a promising replacement site for islet transplantation.
ABSTRACT
Objective To investigate the immunoregulatory effect of sirolimus on the xenotransplantation with arterial patch. Methods The xenotransplantation of arterial grafts was taken from the wild-type Bama pigs to cynomolgus monkeys. The peripheral blood mononuclear cells of recipient monkeys at 14 days after xenotransplantation (POD14) were selected as subjects. Dimethyl sulphoxide (DMSO) was used in the control group (volume ratio of 1:1 000) and sirolimus was administered in the sirolimus experimental group (final concentration of 0.1 μmol/L and 0.5 μmol/L). The cells were cultured for 1.0 and 5.5 d, respectively. The activity of POD14 cells was evaluated. The DMSO control and sirolimus experimental groups (final concentration of 0.1 μmol/L) were established and cultured for 5.5 d. The quantity of T and B cells in POD14 cells was counted and the expression levels of cytokines and messenger RNA (mRNA) were quantitatively measured. Results Compared with the DMSO control group, the activity of POD14 cells was significantly decreased after sirolimus treatment at a final concentration of 0.1 and 0.5 μmol/L for 1.0 d (P<0.01-0.001). After sirolimus treatment at a final concentration of 0.1 and 0.5 μmol/L for 5.5 d, the activity of POD14 cells was significantly decreased (both P<0.001). Compared with the DMSO control group, the quantity of CD3+CD4+T cells and CD3+CD8+T cells in POD14 cells was significantly reduced after sirolimus treatment at a final concentration 0.1 μmol/L (P<0.05-0.01), whereas the quantity of CD3-CD20+B cells was considerably elevated (P<0.01). Compared with DMSO control group, the levels of interferon(IFN)-γ, interleukin(IL)-2, IL-4, IL-5 and IL-6 in the sirolimus experimental group were significantly down-regulated (P<0.05-0.001). The expression levels of IFN-γ, tumor necrosis factor(TNF)-α, IL-2, IL-4, IL-5 and IL-6 mRNA were significantly down-regulated (P<0.05-0.001). Conclusions Sirolimus inhibits the proliferation of POD14 cells in the recipient monkeys after xenotransplantation with arterial patch. The underlying mechanism is that the sirolimus can reduce the quantity of T cells and suppress the expression and secretion of immune rejection-related cytokines.
ABSTRACT
Objective To investigate the optimal condition for the detection of anti-non-galactose (Gal) xenoantigen and antibody in human serum.Mehtods Peripheral blood mononuclear cell (PBMC) obtained from Wuzhishan miniature pig models with α-1,3-galactosyltransferase gene knockout (GTKO) were used as target cells,mixed and incubated with healthy human serum of different concentrations (4.8％,16.7％ and 100％) for 0.5,1.0,2.0,3.0 and 6.0 h,respectively.The abilities of PBMC to bind with IgM and IgG were detected by flow cytometry.Results At the serum concentration of 16.7％,the ability ofnon-Gal IgM to bind with PBMC was significantly enhanced from 0.5 h to 3.0 h incubation (P＜0.01),whereas no statistical significance was noted in terms of IgG (P＞0.05).Increasing serum concentration could also enhance the ability of non-Gal IgM to bind with PBMC.At the serum concentration of 100％ and incubation for 3 h,the ability of IgM to bind with PBMC was the highest among all groups (P＜0.01).At the serum concentration of 100％ and incubation for 6 h,the ability of IgG to bind with PBMC was significantly enhanced (P＜0.05).Prolonging incubation time and increasing serum concentration did not affect the activity of PBMC.Conclusions The optimal condition for detection of anti-non-Gal xenoantigen and antibody is determined.A quantity of 1×105 PBMC from pig should be incubated with 100％ human serum for 3 h for detection of IgM level,or incubated with 100％ human serum for 6 h for measurement of IgG level.This optimized condition contributes to screening the donor pigs which lowly express non-Gal antigen.
ABSTRACT
To establish a platform to monitor the immune rejection after abdominal aortic patch suture in a xenotransplantation model.Methods The carotid was excised from wild-type Bama pigs,cut into 2.5 cmx 1.0 cm pieces in shuttle shape and subsequently sutured to the abdominal aorta of cynomolgus monkeys.No immunosuppressive agent was administered.General conditions of the recipient monkeys were observed.The morphological changes of the graft artery were assessed by pathological examination at postoperative 1 year.Before and 7,14,28 and 49 d after surgery,the blood samples were collected from the recipient monkeys.The serum levels of IgM and IgG antibodies were quantitatively measured by the red blood cell and peripheral blood mononuclear cell (PBMC) from Bama pigs.The quantity of lymphocytes in the recipient monkeys was detected by routine blood test and flow cytometry.Results All 3 monkeys undergoing transplantation survived well.At postoperative 1 year,the lateral tissues of the vascular wall at the artery graft were seen in dark red color.Hematoxylin-eosin (HE) staining revealed a large quantity of red blood cell and platelet deposition,accompanied with lymphocyte infiltration.Using porcine red blood cell and PBMC as target cells,the serum levels of anti-pig IgM and IgG antibodies peaked at postoperative 28 d,and slightly declined at postoperative 49 d.The quantity of lymphocytes and T cell subset also peaked at postoperative 28 d and began to decrease at postoperative 49 d.Conclusions Artery patch suture is a simple and reliable xenotransplantation model.The recipients can maintain normal physiological state without the use of immunosuppressive agents.The grafts can effectively activate the immune system of the recipients,induce the production of anti-pig antibodies and provoke cellular immune rejection.Therefore,this model can be utilized to monitor the immune rejection throughout the xenotransplantation process.