The worldwide shortage in the supply of donor organs and tissues is becoming more pronounced. Xenotransplantation may probably give the hope to overcome the problem ultimately. However, it gives rise to a number of social and ethical issues, among them, the pig appears to be a likely source for human transplantation because it entails least social and ethical issues than no-human primates or other animals and the pig is similar to human in many aspects. The ethical and economic aspects must also be taken into consideration. Patient and his family’s privacy may be stripped because the patient has received a new or unusual treatment. Xenograftings will squint towards a kind of commodities which are different from human graftings and it is a challenge to human transplantation. Xenotransplantation brings a risk of creating new human disease and pandemic, so, it is necessary to formulate a policy and provide input to draft guidelines on the regulation of xenotransplantation.
OBJECTIVE: To explore the kidney anatomic structure of banna minipig inbred-lines, and to provide data for kidney xenotransplantation. METHODS: The fresh and infused kidneys of banna minipig (including the vessel and the ureter) were checked by anatomic microscope and vernier caliper in original location and away body. The tissue structure was observed by HE stain. RESULTS: The structure of kidney of banna minipig inbred-lines (including the vessel and the ureter) are similar to that of human being. The fascia propria of kidney is divided into three layers including capsula fibrosa, capsula adipose and fascia renalis. The thickness of cortex renalis is (20.0 +/- 2.4) mm. The average diameter of renal artery is 5.1 mm and is similar to that of human being. All the kidneys of banna minipig inbred-lines have a single branch renal artery. The diameters of left and right ureters are 5.1 mm and 4.7 mm, respectively. CONCLUSION: The kidney of banna minipig inbred-lines is an ideal replacement of human kidney for xenotransplantation.
Objective To summarize the research progress of xenotransplantation.Methods Domestic and international publications about xenotransplantation were summarized and reviewed. Results Hyperacute xenograft rejection was a huge problem for xenotransplantation， but it could be alleviated if the organs or tissues of donor were genetically modified. So far the graft survival time differed greatly due to characteristics of different organ. Conclusions By reviewing the studies of relevant papers about xenotransplantation， a comprehensive understanding of research background and a suitable research direction of xenotransplantation can be supplied. The graft organs or tissues from genetically modified donors are expected to avoid or alleviate hyperacute xenograft rejection.
OBJECTIVE To investigate the mechanism of xenotransplantation rejection and the interaction between the immunocytes. METHODS: This review concluded the research achievements and new advances in xenotransplantation based on the relevant experimental data. RESULTS: Transgenic pig technology and novel immunosuppressants were applied to suppress hyperacute rejection and acute vascular rejection respectively. Modulation of T cell and antigen presenting cells and induction of tolerance were taken for the prevention of acute cellular rejection. CONCLUSION: In general, the technology of transgenic pig is relatively mature and effective. The mechanism and prevention of acute vascular rejection and acute cellular rejection should be further investigated.
Objective To review the current condition, test method and progress of the animal model of xeno graft versus host disease(xeno GVHD). Methods The literature review and comprehensive analysis methods were used in this article. Results Implanted immunologic cells, the recepient had the chance of showing host versus graft reaction, GVHD or microchimerism. Now, xeno GVHD could be induced in vivo at small and large animals, it also could be supervised through many ways. Conclusion Chimeric cell is very important to xeno-GVHD animal model. With this model, we can really mimic the immunologic change in vivo after xenotransplantation.
OBJECTIVE: Porcine stress syndrome (PSS) is one kind of molecular genetics defect diseases of pig which will cause malignant hyperthermia syndrome (MHS) and is the first index should be excluded in screening of a pig species for xenotransplantation. It was reported that mutation of pig rynodine receptor(RYR1) gene is the main reason for PSS. In this study, RYR1 genotypes of the Chinese Banna mini pig inbred line and inbreeding closed colony Wuzhishan pig were investigated with polymerase chain reaction-restriction endonuclease fragment length polymorphism (PCR-RFLP) technique. METHODS: Antevenocaval whole blood samples were collected from 50 Banna mini-pig inbred-line(BMI), 15 inbreeding Wuzhishan pig (WZSP) and 25 Neijiang pigs (NJP) as negative control, the primer were designed and synthesized, PCR reaction was conducted following the sequence of 94 degrees C (1 min), 58 degrees C (1 min) and 72 degrees C (1 min) for 30 cycles. The PCR products were digested with restriction endonuclease HhaI and then electrophoresis check. RESULTS: A 659 bp DNA fragment was amplified with these two primers, the HALNN sample fragment was cut into fragments as 493 bp and 166 bp individually after the digestion, indicates no point mutation at site 1,843 in RYR1 gene in all tested BMI pig and WZSP. Namely, the RYR1 genotype of 50 cases of BMI and 15 cases of WZSP were HALNN, therefore their phenotype is PSS negative. CONCLUSION: It indicates that the genotype of Banna mini pig inbred line and inbreeding Wuzhishan pig are HALNN therefore PSS absolutely negative, the group penetrance is 0. This is consistent with experimental observation. It suggests that Banna mini pig inbred line and inbreeding Wuzhishan pig may be the alternative donor for xenotransplantation.
Insufficient supply of organ for allotransplantation made the study on finding new organ resources from animal progress. Pig is regarded as one of the optimal donor animals for human. The major obstacle in this field is hyperacute reaction (HAR), which is triggered after the xenogenic natural antibodies preexisting in recipient blood combine to the antigens on the surface of the endothelium and activate the complement system. alpha-Galactose residues (alpha-Gal) on the endothelial cell have been identified as the major xenoantigens. NJZ Pig has been closely breed since 1938, whose family history is clear. Tissue samples from heart, liver, kidney, pancreas, lung, small intestine, skin, spleen, thymus and lymph node were obtained and embedded in paraffin. The sections were performed the immunohistochemical staining with the sera from health volunteers (including all the blood types) as the primary antibodies as well as the biotin labeled bandeirae simplicifolia I isolectin B4 (BS I-B4), which has specific affinity to alpha-galactose. All the staining sections were compared with the tissues digested with alpha-galactosidase. There was no difference between the antigens recognized by sera of different blood types. alpha-Gal was still the major xenoantigen on the endothelial cells. There might exist non-alpha-Gal antigens on the distal convoluted tubules and collecting tubules of the kidney. There was no alpha-Gal distributing on the secreting part of pancreas, either the islet cells or the matrix cells, but surely on pancreatic duct and vessels. All the antigenity was destroyed after the enzyme digestion except that the small intestine gland still positive with the BS I-B4. alpha-Gal is the major xenogenic antigen in NJZ Pigs. There exist some unknown antigens on the distal convoluted tubules and collecting ducts of the kidney. The blood type of recipient is not the first affair to be considered in pig-to-human xenotransplantation. The specificity of BS I-B4 for the alpha-galactose needs more detail research.
Objective To investigate the immunological rejection after hepatocyte transplantation for acute liver failure （ALF） in mice．Methods The hepatocytes were isolated from pig，BALB/c and C57BL/6 mice livers were conducted and then transplanted into C57BL/6 mice．CCl4 was used to make ALF mice model．The experimental animals were randomly divided into three groups， including syngenic group，allogeneic group，and xenogenic group．The survival statuses of all the mice were recorded. The alteration of T lymphocyte subsets，immune globulin，and cytokine were determined．Results ①The survival ratio was 8/10，6/10， and 3/10 in the syngenic group， allogeneic group， and xenogenic group， respectively．The survival ratio in the syngenic group was significantly higher than that in the other two groups （P＜0.05）．②The CD4+ and CD8+ T cells of the peripheral blood in the syngenic group did not change significantly on week one after transplantation．The CD4+ T cells in the allogeneic group reached the peak on day 3 after hepatocyte transplantation （P＜0.05）， while CD8+ T cells did not change much in one week．The CD4+ and CD8+ T cells in the xenogenic group increased and reached the peak on day 3 after transplantation （P＜0.05）．③There were no significantly differences of IgM and IgG in the syngenic group among 0.5， 1， and 3 d after transplantation. IgM of the allogeneic group and xenogenic group reached the peak on day 1 （P＜0.05） and IgG reached the peak on day 3 （P＜0.05） after transplantation．④The concentrations of IFN-γ， TNF-ɑ， and IL-2 in the allogeneic group and xenogenic group were significantly higher than those in the syngenic group （P＜0.05）．The concentration of IL-6 of the xenogenic group was higher than that of the other two groups （P＜0.05）. Conclusions CD4+ and CD8+ T cells play an important role in immune response to both allogeneic and xenogenic hepatocyte transplantation， as well as induce humoral immune response early after hepatocyte transplantation．
After escaping from the hyperacute rejection (HAR), the xenograft has to be faced the challenge of acute vascular, acute cellular and even chronic rejection. Endothelial cells have been confirmed as a kind of antigen processing cell (APC) in allo-rejection. The porcine aortic endothelial cell (PAEC) expressed SLA-II and B7 which are the characteristics of professional APC. PAEC also has plenty of alpha-Gal residues, whether the antigen play any role in the post-HAR is still unknown. Human and porcine peripheral blood lymphocyte (PBLC) were isolated and divided into two parts, one for the effectors and the another were incubated with mitomycin C (MMC) as stimulators. The two kinds of PBLC were mixed-cultured within five days. Cultured PAEC from NJZ Pig was incubated with MMC and divided into two: One digested with alpha-galactosidase. The two kinds of PAEC were taken as stimulators to mixed-culture with human PBLC for five days. All the proliferation was detected with 3H-TdR intermingled in the system. The results showed that allo-MLR was ber than xeno-MLR in the cases. The proliferation was much ber when PAEC was used as the stimulator than that of porcine PBLC. However, the response was remarkably decreased after the digestion of alpha-Gal with alpha-galactosidase. The conclusion was that the low response of porcine-to-human MLR in vitro might be related to the predominant indirect pathway of antigen recognition in this system. While PAEC was used as the stimulator the proliferation in MLR was ber which might be concerned that PAEC itself was an APC as well as xeno-antigen sources, thus the direct pathway was predominant and worked more efficiently. The alpha-Gal might induce T cell proliferation through the linkage with the biological big molecules working as a complete antigen. The other post-HAR antigen might also exist in PAEC such as SLA-II, etc.
OBJECTIVE To evaluate the general situation of the native pig breeds and the relative present study conditions for better development of xenotransplantation in China. METHODS By comparing the profits between the pigs and the non-human primates as the potential donors for xenotransplantation and emphasizing the source of the pigs as the organ donors from the transplantation studies, we analyzed the possible values of the native pig breeds as the donors. RESULTS As one of the richest resources in the world, the species variation and relative genetic stability of Chinese native pig breeds could be the very valuable resources for xenotransplantation study and utilization. As a reverse, the xenotransplantation could provide opportunity for more economically and environmentally utilization of the pigs besides as the meat supply. CONCLUSION As a very valuable and potential resource of organ donor, the native pig breeds of China might be noticed by the xenotransplantation colleagues in the world. It is necessary, to keep the balance among the risk vs. benefit and the protection vs. utilization of this valuable resource.
