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.
Objective To summarize the significance of CYP3A5 in individualized immunosuppressive treatment with tacrolimus (FK506) after liver transplantation. Methods Relevant literatures about the effect of CYP3A5 polymorphisms on the pharmacokinetics of tacrolimus in liver transplant recipients, which were published recently domestic and abroad, were reviewed and analyzed. Results Tacrolimus was used effectively to prevent allograft rejection after liver transplantation. Narrow therapeutic range and individual variation in pharmacokinetics made it difficultly to establish a fixed dosage for all patients. Genetic polymorphism in drug metabolizing enzymes and in transporters influenced the plasma concentration of tacrolimus. CYP3A5 genotype had an effect on the tacrolimus dose requirement in liver transplant recipients.Conclusion Genotyping for CYP3A5 may help optimal individualization of immunosuppressive drug therapy for patients undergoing liver transplantation
Limitation of donor source for allograft makes the research on xenograft progress. Pig is regarded as one of the ideal donor animals. The major obstacle in xenograft is hyperacute rejection, which is caused by complements after they are activated by xenogeneic antigens combined with natural antibodies. It has been confirmed that alpha-Gal is the major target antigen, whose expression is incharged by alpha-1,3 galactosyltransferase (alpha-GT). The approaches to overcome hyperacute rejection against alpha-Gal included: immunoadsorption of xenogeneic natural antibodies, lysis of antigen by enzyme and genetic manupilation to obtain animal lack of alpha-GT. Besides alpha-Gal, there were other antigens binding to human serum antibody, such as gp65 and gp100, which was expressed on PAEC after induced by TNF, the A-like antigen. But their function was still unknown. It was debatable on the role of MHC in xenograft. Both direct and indirect pathway were involved in cellular response in xenograft.
ObjectiveTo compare the effect and safety of basiliximab in ABO incompatible pediatric liver transplant recipients.MethodsABO incompatible pediatric liver transplantation operated between January 2019 and August 2020 were studied. The patients were allocated randomized into two groups. Patients in experimental group were treated with basiliximab as immune induction therapy, but basiliximab was not used in patients of control group. Tacrolimus combined methylprednisolone were used after liver transplantation. The clinical characteristics, graft and recipient survival rate, rejection, infectious complications, and kidney functions after liver transplantation were observed. Donor specific antibody (DSA) was tested in 3 months after liver transplantation. The growth and development were assessed too after liver transplant.ResultsFourty-four patients were enrolled in the study, including 19 patients in the experimental group and 25 patients in the control group. The median follow-up time was 16.6 months (3.8–25.4 months), and there were no statistically differences between the two groups in terms of age, sex, weight, pediatric end-stage liver disease (PELD) score, and other basic conditions. There were no significant differences between the two groups in tacrolimus dose, tacrolimus trough concentration, kidney functions, height and weight growth after liver transplantation. There were no statistical differences in lung infection, blood stream infection within 3 months after liver transplantation, cytomegalovirus, EBV infection, graft/patient survival rate after liver transplantation (P>0.05). However, the acute rejection rate was lower and the DSA positive rate in 3 months after liver transplantation was lower in the experimental group (P<0.05).ConclusionsBasiliximab can be safely used in ABO incompatible pediatric liver transplant recipients. Acute rejection rate and DSA positive rate after transplantation can be decreased with the useof basiliximab.
Objective To insure early detection and hence efficient prevention of allograft rejection in transplanted heart, investigate possible applications of NAD(P)H fluorescence components analysis at the level of living cardiac cells to propose new approaches for diagnosis of rejection. Methods NAD(P)H was studied for noninvasive fluorescent probing of the mitochondrial function. Human cardiomyocyte were isolated from one additional endomyocardial biopsy (EMB) of 14 pediatric patients with heart ransplantation. Rat cardiomyocyte (n=5, 13-14 week old) were also isolated by the same approach for human myocytes. Autofluorescence(AF) was recorded in living cardiomyocytes following excitation with 375 nm UVlight and detection by spectrallyresolved time correlated single photon counting (TCSPC), based on the simultaneous measurement of the fluorescence spectra and lifetimes. Rat cardiac cells were divided into four groups: normoxic condition, normoxia with Rotenone, ischemic condition and ischemia with Rotenone. Comparison of cardiomyocyte AF between human and rat; compared kinetics of rat cardiomyocytes AF in normoxic conditions to ischemiamimicking ones, induced at physiological temperatures by reducing cell pH and oxygen content; comparison of cardiomyocyte AF dynamic changes in transplanted pediatric patients presenting either no rejection (R0) or mild rejection (R1). Results We have achieved appropriate isolation of living cardiomyocytes from human biopsies, as well as from rat cardiac tissues and determined their AF. At least a 3-exponential decay with 0.5-0.7ns, 1.9-2.4 ns and 9.0-15.0 ns lifetime pools is necessary to describe human cardiomyocyte AF within 420560 nm spectral range. Rat cardiomyocyte steadystate AF in ischemiamimicking condition was significantly increased when compared normoxic ones (Plt;0.05); application of Rotenone induced a significant increase in AF intensity in ischemic and normoxic condition, however no significant difference between the two groups (Plt;0.05).Human cardiomyocyte AF was found significantly lower in comparison to experimental rat model in the same condition(Plt;0.05). A correlation between changes in steadystate NAD(P)H fluorescence and rejection grades was found when comparison of R1 to R0. R1 showed significantly increased fluorescence intensity (Plt;0.05), without change in the spectra shape, results can be comparable to the effect of ischemiamimic conditions. Conclusion Our studies clearly demonstrated that spectrallyresolved fluorescence spectral analysis coupled to fluorescence lifetime are high sensitive approaches to examine mitochondrial metabolic oxidative state directly in living human cardiomyocytes with good reproducibility. Human cardiomyocytes are more metabolically active than the rat ones, while this activity (and thus ATP production) seems lowered during rejection process. In perspective, the advantage of this method is the possibility of its combination to multiphoton confocal microscopy, which can result in the adaptation of this approach directly to tissue biopsy, as well as in vivo directly via cardiac catheterization without the necessity of cell isolation. This approach provides promising new tool for clinical diagnosis and treatment of allograft rejection, and will enhance our knowledge about cardiomyocyte oxidative metabolism and/or its dysfunction at a cellular level.
ObjectiveTo evaluate the effects and mechanism of indoleamine 2, 3-dioxygenase (IDO) modified rat bone marrow mesenchymal stem cells (BMSCs) in composite tissue allograft rejection. MethodsBMSCs isolated from Brown Norway (BN) rats (aged, 4-6 weeks) were infected by IDO[green fluorescent protein (GFP)]-lentivirus. The high expression target gene and biological activity cell line (IDO-BMSCs) were screened. IDO mRNA and protein expressions were detected by RT-PCR and Western blot. The biological activity of IDO in supernatant was detected by measuring the amount of kynurenine generation. In mixed lymphocyte reaction system, different numbers of IDO-BMSCs mixed with responding cells (peripheral blood mononuclear cell isolated from 4-6-week-old LEWIS rats, as recipient) and stimulating cells (peripheral blood mononuclear cell isolated from BN rats, as donor), with the cells ratios of 1:5:5, 1:10:10, 1:50:50, and 1:100:100 (as experimental groups 1, 2, 3, and 4, respectively). Each reaction system was blocked by 1 mmol/L 1-methyl-tryptophan (1-MT) (IDO specific inhibitor). IDO-BMSCs mixed with responding cells (1:5) as the negative control group, responding cells mixed with stimulating cells (1:1) as positive control group; and IDO-BMSCs were cultured in RPMI 1640 medium alone as blank control group. MTT assay was used to detect the T lymphocytes proliferation at 5 days. Furthermore, GFP-BMSCs (group A), IDO-BMSCs (group B), and normal saline (group C) were infused via the tail vein of allogeneic limb transplantation rats, and graft survival time and rejection were observed in each group. ResultsThe IDO expression of BMSCs after genetic modification was higher than that before genetic modification. IDO-BMSCs could significantly improved kynurenine concentration in culture medium supernatant when compared with GFP-BMSCs (P<0.05). Before adding 1-MT, with the ratio of IDO-BMSCs to responding cells decreased, T lymphocytes proliferation rate increased in experimental groups 1, 2, and 3, showing significant differences between groups (P<0.05); there was no significant difference between experimental group 4 and the positive control group (P>0.05). After adding 1-MT, T lymphocytes proliferation rate was significantly higher than that before adding 1-MT in the other experimental groups (P<0.05) except experimental group 4 (P>0.05). In vivo, IDO-BMSCs could promote colonization in allograft, inhibit transplantation rejection, and prolong survival time of composite tissue allograft; the survival time of composite tissue allograft was (11.5±0.6) days in group A, (14.5±0.8) days in group B, and (9.0±0.3) days in group C, and it was significantly longer in group B than in groups A and C, and in group A than in group C (P<0.05). ConclusionIDO-BMSCs can promote the survival of allogeneic composite tissue grafts in rats, and its mechanism may involve in inhibition of T lymphocytes proliferation and promotion their own colonization in allograft.
Objective To investigate the expression of RNA editase ADAR1 in the lymphocytes in rats’ spleen with liver transplantation rejection. Methods Thirty SD rats and 75 Wistar rats were included. Fifteen livers from Wistar rats were transplanted to 15 Wistar rats (isograft group), 30 livers from SD rats were transplanted to 30 Wistar rats (allograft group and allograft+FK506 group), and 15 of them were then intramuscularly injected with FK506, 2 mg/(kg·d), the other 15 Wistar rats were only operated similarly to the other rats without any liver transplantation (control group). Five rats were killed and their splenetic tissues were collected on day 3, day 5, and day 7, respectively. The expression of ADAR1 mRNA in lymphocytes of the spleen in acute rejection was detected by RT-PCR. Results Different performance of pathology was observed in all the liver and spleen tissues from the transplanted rats over time, especially in allograft group. The expression of ADAR1 mRNA in the allograft group was significant higher than that of isograft and allograft+FK506 groups （P＜0.001）, especially on the 5th day. Conclusion There was a significant positive correlation between expression of ADAR1 and the severity of acute rejection, but the mechanism by which ADAR1 affected the acute rejection is unknown and needs to be further studied. FK506 may inhibit the expression of ADAR1 and remarkably reduce the severity of acute rejection.
ObjectiveTo investigate the early diagnostic value of transforming growth factor-β1(TGF-β1) on acute rejection after liver transplantation in rhesus by detecting the expression of TGF-β1 in the liver tissue. MethodsLiver transplantation models in rhesus were constructed by the improved vascular dual cuff, supporting tube of biliary tract, and artery anastomosis method.The successful models were randomly divided into experimental group (no immunosuppressant treatment in perioperative period) and control group (treated by immunosuppressant in perioperative period).Then the blood samples and liver tissues were collected at 6, 12, 24, and 72 hours after surgery.Allograft rejections of liver tissue after liver transplantation were monitored by liver function test, hematoxylin-eosin staining and Banff score.Finally, the expression level of TGF-β1 was detected by Western blot analysis or immunohistochemistry technique. Results①The acute rejection happened in all the rhesus at 12 h, 24 h and 72 h after liver transplantation, especially at 72 h after liver transplantation in the experimental group, the Banff grade levels of acute rejection in the liver tissue was more severe than that in the control group (P < 0.05).②The levels of ALT, AST, and TBIL after liver transplantation was gradually increased, which were similar at 6 h and 12 h after transplantation between the two groups, but which at 24 h and 72 h after transplantation in the experimental group were significantly higher than those in the control group (P < 0.05).③The results of TGF-β1 protein expression using immunohistochemical detection:The percentage of positive area of TGF-β1 of liver tissue at 12 h in the experimental group was significantly higher than that in the control group (P < 0.05).With the extension of time, it was gradually increased and significantly higher than that in the control group at 24 h or 72 h (P < 0.05).④The semi-quantitative results of TGF-β1 protein expression using Western blot detection:The TGF-β1 protein expressions began to increase at 6 h after liver transplantation in the experimental group and the control group, and the magnitude of increase was more obvious in the experimental group.The TGF-β1 protein expressions at different time (6 h, 12 h, 24 h, and 72 h) in the experimental group were significantly higher than those in the control group (P value was 0.003, 0.001, 0.001, and 0.001, respectively). ConclusionsThe elevated level of TGF-β1 of liver tissue after liver transplantation might suggest the enhanced cellular immune function, it might have certain significance for early diagnosis of acute rejection after liver transplantation.
目的探讨肝移植后育龄妇女的怀孕及分娩对胎儿的影响。方法分析了中国大陆首例肝移植妇女肝移植、免疫抑制剂使用及成功怀孕和分娩的情况。 结果本例妇女因硬化性胆管炎，胆汁性肝硬化，肝脓肿，脾大而行同种原位肝移植术，术后2年9月第二次成功怀孕并分娩出发育正常的男婴。结论肝移植后育龄妇女同样可以正常怀孕，但是发生早产和胎儿发育相对迟缓的几率增加；怀孕过程中应该严密地监控母亲的器官功能改变和胎儿的发育情况，并且应合理选择和使用免疫抑制剂。