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.
ObjectiveTo investigate the aim antigen coursing the hyperacute rejection of xenotransplantation. MethodsDocuments about hyperacute rejection in xenotransplantation were reviewed and summarized in detail. ResultsPig is thought to be one of the ideal donors of xenotransplantation, but the major obstacle is hyperacute rejection mediated by complement that is activated though human serum. αGal is recognized as the major antigen and its expression is controlled by α1,3 galactosyltransferase. Immunoabsorption of preexsisted antibody, enzymatic digestion of αGal, knockout αGT gene and transgenic technology have been used to solve this problem. Even so, there remain other antigens which can combine with natural antibodies in human serum, such as, 40×103 molecule in erythrocyte, 210×103, 105×103 and 50×103 antigen in pig embryo brain cell, etc. Conclusion αGal is the major antigen which course the hyperacute rejection. Besides αGal, many nonalphagal need further investigation.
ObjectiveTo study the mechanism of reducing the intratumoral microvessel density (MVD) by Ginsenoside Rg3 (Rg3) combined with cytotoxic agent in xenotransplanted human breast infiltrating duct carcinoma in nude mice. MethodsSixteen female nude mice were randomly divided into 4 groups to receive cyclophosphamid (16 mg/kg,qd) combined with Rg3 (10 mg/kg, qd),Rg3(10 mg/kg,qd) alone,cyclophosphamid (16 mg/kg,qd) alone and 0.5% sodium carboxymethyl cellulose (0.5 ml,qd) respectively for 55 days. Breast cancer mass were weighed and sampled for light microscopic observation. The intratumor MVD was examined by immunohistochemical staining. ResultsThe tumor weight of treated group was significantly lower than that of control group. The tumor weight of the Rg3 combined with CTX group was lower than that of Rg3 group. The MVD value of Rg3 group was significantly lower than that of CTX group and control group. The MVD was significantly reduced in the Rg3 combined with CTX group than that in the others.ConclusionRg3 combined with CTX can inhibit the growth of xenotransplanted human breast infiltrating duct carcinoma, and reduce the intratumoral MVD.
Objective To evaluate tissue regeneration, body reaction, and biological safety of xenogeneous bladder acellular matrix (BAM) that can be used to repair rabbit bladder. Methods Porcine BAM was prepared through physical, chemical, and enzymatic methods, and the effects of acellularization and the structure were observed with HE staining and scanning electron microscope (SEM). Eighteen New Zealand white rabbits (weighing, 2.5-3.0 kg) undergoing partial cystectomy were randomly divided into 2 groups. After partial (about 30%) cystectomy, the porcine BAM was used to replace partial rabbit bladder in the experimental group (n=12), and the incision was directly sutured as control group (n=6). The survival condition of animals was observed after operation. At 15 days, 1, 2, 3, and 6 months after operation, the blood routine, renal function, and electrolyte were tested by collecting the blood samples. At 1, 2, 3, and 6 months after operation, maximum bladder capacity, bladder leak point pressure, and bladder compliance were measured through urodynamic studies. Then gross observation was performed for regeneration of bladder, and the specimens of the bladder were harvested for HE staining and immunohistochemical staining. The surrounding organs and local lymphoid tissues were harvested for gross observation and HE staining. Results Cell components were completely removed in the porcine BAM, showing three-dimensional porous structure under SEM. All the animals survived during the experiment. At 15 days after operation, white blood cell count increased, and then returned to normal level in 2 groups, showing no significant difference between 2 groups (P gt; 0.05). The tests of renal function and electrolyte suggested no significant difference between 2 groups (P gt; 0.05). The level of serum creatinine showed a tendency of increase, but it remained within normal range at 6 months after operation. The maximum bladder capacity and compliance in experimental group were significantly higher than those in control group at 3 and 6 months after operation (P lt; 0.05), but no significant difference in bladder leak point pressure at each time point between 2 groups (P gt; 0.05). The urothelial regeneration, smooth muscle regeneration, and blood vessel regeneration were seen by histological observation in 2 groups. In the 2 groups, chronic inflammatory cells infiltration could be observed at 1 month postoperatively, and then chronic inflammatory cells decreased significantly (P lt; 0.05), until complete disappearance. There was no significant difference in score of chronic inflammatory cell infiltration between 2 groups at 3 and 6 months after operation (P gt; 0.05). The α-smooth muscle actin expression was significantly increased with time passing in 2 groups (P lt; 0.05), and it was significantly higher in control group than in experimental group at each time point (P lt; 0.05). In addition, gross and HE staining observations showed no abnormalities in surrounding organs and local lymphoid tissues. Conclusion No immune rejection response occurs when porcine BAM is used for xenotransplantation. It is indicated that porcine BAM is relative safety for xenotransplantation.
Objective To review the methods of overcoming immunological rejection in xenotransplantation.Methods The strategies of overcoming immunological rejection in xenotransplantation were analyzed and summaried on the basis of an extensive review of the latest l iterature concerned. Results The research development of immunological rejection mechanism and molecular biological technique provided new approaches for overcoming immunological rejection in xenotransplantation. Conclusion It is only a matter of time for xenotransplantation to be appl ied cl inically.
To investigate the immunoreaction, histological reaction and turnover by comparing the xenotransplantation of fresh human amniotic membrane (HAM) with that of preserved HAM, and to analyze the cl inical appl ication value of different kinds of HAM preparations. Methods Subcutaneous implant models were establ ished in 150 BALB/C mice, which were randomized into 5 groups of 30 mice each, based on different implants: fresh amniotic membrane (FAM), double fresh amniotic membrane (DFAM), glycerin preserved amniotic membrane (GPAM), chorion (positive control) or merely operation (negative control). The tissue samples from grafted area were observed with SABC and HE staining, and the inflammatory cells were calculated with l ight microscopy. 1, 2, 4, 8 and 12 weeks after surgery. Results The mice in all of groups were normal in eating and moving, and the wound surface healed well. In all of AM groups, the expression of MHC Ⅱ and the calculation of inflammatory cells were much less than those in chorion groups, showing significant differences (P lt; 0.01). At 1, 8 and 12 weeks after surgery, there were no significant differences in the expression of MHC Ⅱ and the calculation of inflammatory cells in all of AM groups, compared with other groups (P gt; 0.05). From 2 weeks to 4 weeks after surgery, there were no significant differences in the expression of MHC Ⅱ and the calculation of inflammatory cells between FAM and DFAM groups (P gt; 0.05), but they were both more than those in GPAM groups, showing significant differences (P lt; 0.05). At the 4th week after surgery, in all of AM groups, the expression of MHC Ⅱ and the calculation of inflammatory cells were less than those at the 2nd week, showing significant difference (P lt; 0.01).The amniotic epithel ium was still al ive in fresh AM groups until 4 weeks after transplantation. Early after surgery, fibroblasts infiltrated AM from the substantia basilaris layer while made fibrous capsule around the epithel ium. After 12 weeks, the amnion absorbed. Conclusion As a kind of heterologous biomaterial, whether fresh or preserved, HAM can be seemedof ideal immunocompatibil ity and histocompatibil ity. Fresh HAM with al ive epithel ium may be more successful in area ofrepair and reconstruction.
Objective To improve the Heron’s technique for heterotopic cardiac transplantation in rats by cuff vessel anastomosis in some aspectsand successfully establish the simplified model of cervical cardiac xenotransplantation from guinea pigs donor to SD rats recipients. Methods The donors were 64 male guinea pigs, whose weight ranged from 250 to 350 g； the recipients were 64 male SD rats, whose weight ranged from 300 to 350 g.The guinea pigs donor’s ascending aorta and pulmonary artery were anastomosed to SD rats recipient’s right common carotid artery and external jugular vein respectively with a self-made “sleeve” anastomosis. The modified cuff technique of heterotopic grafting is described in detail. Results 64 consecutive successful transplantations have been performed by single surgeon were done with negligible operative risk. No anastomosis leakage nor vessel obstruction. The total time of surgical procedure were 45 to 60 minutes. The new technique allowed vascular anastomoses to be completed in 2 to 5 minutes. The total cold ischemia time for donor heart was 14 minutes in average. Conclusion This modified Heron’s technique was a simple, economical, practicable,reliable and high reproducible model can be operated by surgeons with minimal training in microvascular surgery, and be applied to various transplantation immunological studies.
OBJECTIVE To detect the immunoreaction after osteoblast xenotransplantation and to investigate the possibility of heterogenic osteocyte transplantation and tissue engineered bone reconstruction. METHODS: Rat osteoblasts were isolated by two-part bony digestion/elements in culturing, and incubated in vitro at 37 degrees C, 5% carbon dioxide for 5 days until they multiplied and formed a monolayer on the bottom of dish. Twenty-eight rabbits were divided into 3 groups. Autograft of osteoblasts(group A), xenograft of osteoblasts(group B) and normal saline(group C) were implanted into the rectus abdominus muscle. The immunological and histological observations were performed after 1, 2, 4 and 8 weeks of transplantation. RESULTS: Cultured cells reached confluence within 5 days and was identified as osteoblasts by ALP staining and Bon kossa staining. The result of host versus graft reaction was negative. In group B, specific antibody reaction was detected 2 weeks and 4 weeks after transplantation. Cell mediated cytotoxicity was detected after 2 weeks, reached the peak value 4 weeks later, and then began to decline 8 weeks later. HE staining showed mass inflammatory cells and no ectopic ossification after 8 weeks. CONCLUSION: Heterogenic osteoblast transplantation will lead to an obvious change in host humoral and cellular immunity and lost the ability of bone formation. So, it can not be used for the reliable cell sources for osteocyte transplantation or tissue-engineering bone reconstruction.
OBJECTIVE: To observe the heart anatomic and histological structure of the Banna mini-pig inbred-lined and to provide the morphological data for heart xenotransplantation and breeding transgens pig. METHODS: Ten Banna mini-pigs (12-18 months old) were affused and fixed by common coratid artery. The heart were observed and measured by gross anatomy and histology. RESULTS: There were many similarities between the Banna pig heart and the human heart in anatomy and histology. However, the following differences were observed in the Banna pig heart: 1. Azygos vein directly drew into right atrium cordis. 2. The intercalated disk of cardiac muscle was less than that of human. 3. The Purkinje’s fibre was bigger than that of human. CONCLUSION: On the morphology and histology, the structure of Banna pig heart is similar to the heart of human being. It is possible that Banna minipig heart becomes organ donors for xenotransplantation.
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.