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Objective:To explore the feasibility of a stable pig-to-monkey orthotopic liver transplantation (LT) model and provide a favorable experimental tool for preclinical studies of xenotransplantation.Methods:In this retrospective analysis, the authors reviewed the perioperative conditions and outcomes of 7 pig-to-monkey orthotopic liver transplants performed by a xenotransplantation research team of Second Xiangya Hospital.Gene-edited Banna miniature pigs were selected as donors and rhesus monkeys with similar anatomical characteristics, physiology, biochemistry and immune mechanism to humans were selected as recipients for pig-monkey xenogeneic orthotopic LT.Based upon classic transplantation procedures, whole liver xenogeneic orthotopic transplantation was performed.Surgical processes were modified for minimizing intraoperative hemorrhage and shortening anhepatic period.A bile duct drainage tube was implanted for observing bile secretion.ATG + anti-CD20 + snake venom factor and FK-506 were utilized for immunoinduction pre-operation while tacrolimus, mycophenolate mofetil (MMF) and methyl prednisolone for postoperative immunomaintenance therapy.Antibiotics and antiviral agents were also applied and thrombin complex for improving coagulation functions.Results:All procedures were successfully completed.After the stability and maturity of our model, in case No.7, donor's acquisition operative duration was 42 min without heat ischemic time, donor's trimming time 87 min, donor cold retention time 128 min, recipient's operative duration 123 min and anhepatic phase 27 min.Subhepatic inferior vena cava was occluded for 38 min.Blood loss was around 10 ml.And 4/7 models survived post-operation and the longest survival time was 27 h. Among 3 non-survival cases, the causes were anesthesia accident (n=1) and immaturity of early operation (n=2). Model No.7 had a biliary secretion volume of 86 ml post-operation.Conclusions:Qualified donor acquisition, high-quality vascular anastomosis, intraoperative reduction of blood loss, shortening of anhepatic period, strict fluid replenishing and careful monitoring are essential for boosting the success rate of pig-monkey liver xenotransplantation model.Optimization of donor gene combination and advanced immunosuppression protocol help to further achieve the long-term survival of pig-monkey liver xenotransplantation model.
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ObjectiveXenotransplantation is an effective way to address the shortage of human organ donors, but it faces serious immune rejection reactions, including hyperacute rejection caused by blood type differences. Establishing a stable, convenient, and reliable method for pig blood type identification can quickly screen suitable donor pigs for xenograft research.MethodsBanna miniature inbred pigs, Diannan small eared pigs, and Bama Xiang pigs were selected as the research objects. DNA was extracted from the blood, oral buccal mucosa, and fetal fibroblasts of the three strains of pigs using DNA extraction kits. The target fragment of the ABO homologous gene EAA intron 7 in pigs was amplified using PCR method. Blood agglutination reaction was used to detect hemolysis in pig anterior vena cava whole blood after adding anti A and B antibodies. Immunohistochemical method was used to detect the expression level of A antigen in pig heart, liver, spleen, lung, and kidney tissues. Immunofluorescence method was used to detect the expression level of A antigen in pig oral mucosa. By comparing the results of different methods for determining pig blood types, the stability and reliability of the PCR method were verified, and a convenient PCR based pigblood type identification method was established.Results Firstly, the blood PCR results of 69 inbred strains of Banna miniature pigs, 7 Diannan small eared pigs, and 34 Bama Xiang pigs showed 20 AO blood types, 66 AA blood types, and 24 O blood types. The PCR results of fetal fibroblasts from 47 Diannan small eared pigs showed that all 47 fetuses were O blood type. Among them, the oral mucosal PCR results of 8 gene edited cloned pigs were consistent with those of donor fetal fibroblasts, all of which were O blood type. The oral mucosal PCR results of 8 wild-type pigs (2 inbred lines of Banna miniature pigs, 4 Diannan small eared pigs, and 2 Bama Xiang pigs) were consistent with the blood PCR identification results. Then, 11 inbred lines of Banna miniature pigs, 4 Diannan small eared pigs, and 2 Bama Xiang pigs were randomly selected for blood agglutination reaction validation, and the results were consistent with the PCR identification results of both blood samples and oral mucosa samples. Moreover, immuno-histochemical analysis was performed on the heart, liver, lung, kidney, and spleen tissues of one Banna miniature pig inbred line and two Bama Xiang pigs, and the results were consistent with blood PCR identification and blood agglutination reaction results. Finally, oral mucosal samples were collected from 2 inbred strains of Banna miniature pigs and 1 Bama Xiang pig for immunofluorescence detection, and the results were consistent with the blood PCR identification results.ConclusionBy collecting fetal cells and oral mucosal samples from live pigs for PCR detection, the blood type of pigs can be accurately and efficiently identified, providing a convenient method for blood type screening of xenograft donor pigs.
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Objective To investigate the application prospect of the most extensive genome engineering pig internationally in preclinical xenotransplantation. Methods Porcine endogenous retrovirus (PERV) knockout combined with 3 major heterologous antigen gene knockouts and 9 humanized genes for inhibition of complement activation, regulation of coagulation disorders, anti-inflammatory and anti-phagocytosis were transferred into a pig (PERV-KO/3-KO/9-TG) as a donor, and the heart, liver and kidney were obtained and transplanted to 3 Rhesus macaque recipients respectively to establish a preclinical research model of pig-to-Rhesus macaque xenotransplantation. The functional status of xenografts after blood flow reconstruction was observed and the survival of recipients was summarized. The hemodynamics of xenografts were monitored. The change of hematological indexes of each recipient was compared. The histopathological manifestation of xenografts was observed. Results After the blood flow was reconstructed, all xenografts showed ruddy color, soft texture and good perfusion. The transplant heart, liver and kidney showed full arterial and venous blood flow and good perfusion at 1 d after operation. The postoperative survival time of heart, liver, and kidney transplant recipients was 7, 26, and 1 d, respectively. The levels of creatine kinase, creatine kinase isoenzyme, and lactate dehydrogenase increased in heart transplant recipient at 1 d after operation, and gradually recovered to near normal levels at 6 d after operation. All indexes increased sharply at 7 d after operation. The level of aspartate aminotransferase increased in liver transplant recipients at 2 d after operation, and the alanine aminotransferase basically returned to normal at 10 d after operation, but the total bilirubin continued to increase. Both aspartate aminotransferase and alanine aminotransferase increased at 12 d after operation, and reached a peak at 15 d after operation. The kidney transplant recipient developed mild proteinuria at 1 d after operation, and died of sudden severe arrhythmia. Histopathology showed that the tissue structure of cardiac and renal xenografts was close to normal, and liver xenografts presented with patchy necrosis, the liver tissue structure was disordered, accompanied by inflammatory damage, interstitial hemorrhage and thrombotic microangiopathy. Conclusions PERV-KO/3-KO/9-TG pig shows advantages in overcoming hyperacute rejection, mitigating humoral rejection and coagulation dysregulation. However, whether it can be used as potential donor for clinical xenotransplantation needs further evaluation.
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Objective To explore the effects of different body positions at the expiratory phase thinsection multi-slice spiral CT on the diagnosis of pulmonary air trapping after allogeneic hematopoietic stem cell transplantation(allo-HSCT).Methods Thirty-one allo-HSCT patients underwent the expiratory phase low-dose MSCT lung scanning at supine and prone positions to detect whether they have air trapping lesion,the volume percent of air trapping region (CT value ≤-700 HU at expiratory phase) against the whole lung was measured by using GE workstation after grading.Statistical analysis on lesion detection rate was performed with McNemar test and volume percent with rank sum test.Results Air trapping regions were observed in 8 patients (25.8％,8/31) who performed CT scan at the supine position,while 15 cases (48.4％,15/31)were positive for prone position CT scan.Seven cases showed positive results at both body positions.Statistical significance in the positive detection rate at supine and prone positions was found (x2 =4.00,P =0.039).The volume fraction of the two positions was 13 for supine position and 21 for prone position with statistical significance (Z =-3.37,P =0.001).Sensitivity at prone position CT scan to detect air trapping was much higher than that at supine position CT scan.Conclusion For allo-HSCT patients with chronic rejection reaction,performing expiratory phase thin-section CT scan and prone position scan can not only improve the detection rate of lung forepart lesions,but also preliminarily evaluate the severity of the air trapping,which can provide a basis for the early diagnosis and treatment in clinics.