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.

Liver transplantation is a curable therapy to save the life of patients with end-stage liver diseases of different causes. The serious shortage of liver donors led to the death of a large number of patients with end-stage liver disease. Genetic-engineered pigs used for xenotransplantation are one of the potential solutions to alleviate the liver donor shortage, but currently clinical application of such xenogeneic liver grafts is hindered by acute rejection, thrombocytopenia, and coagulation dysfunctions in patients. The development of genetic-engineering technology and the application of new immunosuppressants have controlled the acute rejection of liver xenotransplantation to some extent. However, acute humoral rejection may become another major issue for the long-term graft failure. This review summarized and discussed the potential and underlying mechanisms and preventive measures of acute humoral rejection in liver xenotransplantation.

Objective To investigate the efficacy and safety of programmed cell death protein-1 (PD-1) monoclonal antibody on the treatment of malignant tumor after solid organ transplantation (SOT). Methods The relevant literatures in 7 databases were searched. The data on 54 cases of recipients with malignant tumors treated with PD-1 monoclonal antibody after SOT were collected, and the clinical effects and rejection of SOT recipients treated with PD-1 monoclonal antibody were analyzed. Results Total 32 acceptable articles including 54 SOT recipients were incorporated, including 43 males and 11 females aged 14-79 years old. There are 29 renal transplant recipients, 19 liver transplant recipients and 6 heart transplant recipients. The types of PD-1 monoclonal antibody agent used by SOT recipients included pembrolizumab for 28 patients and nivolumab for 26 patients. The overall remission rate, disease progression rate and fatality rate of PD-1 monoclonal antibody for postoperative malignant tumors of SOT recipients were 32% (17/54), 44% (24/54) and 36% (19/54), respectively. After treatment with PD-1 monoclonal antibody for postoperative malignant tumors of SOT recipients, the incidence of rejection was 39% (21/54), indicating no significant correlation between rejection and type of PD-1 monoclonal antibody (P > 0.05). Conclusions PD-1 monoclonal antibody can effectively treat postoperative malignant tumors of SOT recipients, and may induce rejection during the treatment. But rejection is not the most common cause for death of recipients.

Objective To evaluate the effect of donor risk index (DRI) on the early prognosis of liver transplantation for acute-on-chronic liver failure (ACLF). Methods Clinical data of 159 ACLF recipients undergoing liver transplantation were retrospectively analyzed. According to the calculation formula of DRI, all recipients were divided into DRI < 1.65 group (n=96) and DRI≥1.65 group (n=63). Based on the Chronic Liver Failure Consortium acute-on-chronic liver failure score (CLIF-C ACLFs), all recipients were divided into CLIF-C ACLFs < 48 group (n=78) and CLIF-C ACLFs≥48 group (n=81). The early prognosis indexes including the length of intensive care unit (ICU) stay and the length of postoperative hospital stay of the recipients in each group were observed after liver transplantation. The 90 dsurvival rate of the recipients after liver transplantation was analyzed by Kaplan-Meier survival curve. The risk factors affecting the early prognosis of ACLF recipients after liver transplantation were analyzed by Cox's hazards regression model. Results The length of ICU stay and the length of postoperative hospital stay did not significantly differ between the DRI < 1.65 group and DRI≥1.65 group (both P > 0.05). The length of postoperative hospital stay did not significantly differ between the CLIF-C ACLFs < 48 group and CLIF-C ACLFs≥48 group (P > 0.05). The length of ICU stay in the CLIF-C ACLFs < 48 group was 4 (3-14) d, significantly shorter than 7 (1-33) d in the CLIF-C ACLFs≥48 group (P < 0.05). The CLIF-C ACLFs was a risk factor of the early prognosis of ACLF recipients after liver transplantation (P < 0.05). The postoperative 90 d survival rate did not significantly differ between the DRI < 1.65 group and DRI≥1.65 group (P > 0.05). The postoperative 90 d survival rate in the CLIF-C ACLFs < 48 group was 94%, significantly higher than 79% in the CLIF-C ACLFs≥48 group (P < 0.05). Conclusions The early prognosis of ACLF recipients after liver transplantation is correlated with the severity of the disease rather than the DRI. Liver transplantation should be performed early and promptly.

Objective To evaluate the outcome of 1iver transplantation for acute-on-chronic liver failure (ACLF) patients .Methods We included 453 consecutive patients with previously cirrhosis who underwent liver transplantation between January 2013 and December 2017 .Patients were categorized as no ACLF (n=294) and ACLF(n=159) according to EASL-CLIF consortium criteria .Furthermore ,we used ACLF grades to categorize the ACLF patients .Their clinical data were reviewed and their 90-days survival outcomes were compared .Results Compared with the no ACLF group ,the length of stay in the ICU was significantly prolonged for all patients with ACLF ,and the 90-days survival rate after transplantation was significantly reduced in ACLF group .The length of stay in the ICU was shorter in Grade 1 and Grade 2 group when compared to Grade 3 group .The 90-days survival rate of no ACLF ,Grade 1 ,Grade 2 and Grade 3 group were 93 .20％ ,92 .59％ ,93 .33％ and 73 .68％ ,respectively .There were no statistically significant differences in 90-days survival rate among the no ACLF ,Grade 1 and Grade 2 group .However , the 90-days survive rate of Grade 3 group was lower than that of other groups .Conclusions Liver transplantation has been shown to be safe and effective with good outcome in patients with ACLF and should be offered in early course of ACLF before onset of multi-organ failure .

Objective To construct the orthotopic mouse liver transplantation model and cover troubleshooting,in order to provide experimental techniques support for organ transplantation pathology and immunology studies.Methods Male C57BL/6 mice,10-12 weeks,were selected as the allograft donors.Male C3H mice with same age were selected as the allograft recipients.The orthotopic mouse liver transplantation model consisted of 3 stages,including harvesting the donor liver,back-table preparation of the liver graft and transplantation of the donor liver into the recipient.The average time for harvesting the donor livers was (40 ± 8.8) min,(23 ± 4.7) min for preparing the donor livers and (75 ± 9.6) min for transplanting the donor livers into the recipient.Results Seventy pairs of mice were used for the preliminary experiments.For the formal experiments,the allograft transplantation was established on 220 pairs with 90.4％ successful rate.Conclusion It is the skillful and high quality microsurgical technique that is the guarantee of establishing the orthotopic mouse liver transplantation model successfully.

Monoclonal antibody ( mAb ) represents a class of therapeutics experienced dramatic development over the past 30 years. Because of the tremendous differences in physicochemical and biological properties between mAbs and small molecules, the mAb therapeutics significantly differ from the chemical drugs in pharmacokinetic characteristics and underlying mechanisms. Full understanding of those characteristics and mechanisms may efficiently guide the screening and development of mAb medi-cines, and would well support their safety evaluation and clinical dosage regimen designing. This review is to summarize pharma-cokinetics and underlying mechanisms of mAbs from the aspects of absorption, distribution and elimination, as well as the ap-proaches for prediction of mAb pharmacokinetics in humans.

Objective To study the clinical significance of CD39 on regulatory T (Treg) cells in the peripheral blood (PB) of patients following liver transplantation and to evaluate the relationship between the levels of CD39+ Treg cells in the PB and acute rejection.Methods A prospective study was conducted to compare the CD39+ Treg cells from 76 liver transplant patients with those coming from 20 age-matched healthy individuals.The PB samples were collected within one year at different time points post-transplant.Blood samples and liver biopsies were collected at the time when acute rejection was diagnosed.The percentages of CD39 within the CD4+ CD25+ T cells were measured by using flow cytometry.The liver transplant patients were classified into two groups:the rejection group which consisted of 17 patients who an episode of acute rejection,and the non-rejection group consisted of the remaining 59 patients who had no acute rejection episodes.The percentages of CD39 within the CD4 + CD25 + T cells and the inhibition function of the CD39+ Treg cells were compared between the two liver transplant groups.Results The percentages of CD39 within the CD4+ CD25+ cells were significantly lower in the rejection group during acute rejection as compared to the non-rejection group (P ＜ 0.05).The percentages of CD39 within the CD4 + CD25 + cells were negatively correlated with the Rejection Activity Index (r =-0.86,P ＜ 0.05).The inhibition rate regarding the CD4+ CD25+ CD39+ Treg cells in patients with acute rejection was significantly lower than those without rejection (P ＜ 0.05).Conclusions The percentages of CD39 within the CD4+ CD25+ T cells were significantly lower in the rejection group during acute rejection and were negatively correlated with the RAI.The inhibition rate regarding the CD4+ CD25+ CD39+ Treg cells in patients with acute rejection was significantly lower than those without rejection.

Objective: To explore the protective effect of minocycline on hepatic ischemia-reperfusion injury (IRI) in rats and the underlying mechanisms. Methods: A total of 54 male Sprague-Dawley rats were randomly divided into 3 groups: the sham-operated group (control group), the ischemic–reperfusion (IR group), and the minocycline preconditioning group (n=18 per group). The rats in the minocycline preconditioning group were given minocycline (45 mg/kg) by gastric irrigation at 36 h before operation and then were subsequently administered with minocycline (22.5 mg/kg) at every 12 h. hTe rats were sacriifcedat 2, 6, 24 h after reperfusion. The serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were measured. HE staining of liver tissues was performed to detect the histological changes, and the degree of liver IRI according to Suzuki score were calculated. hTe levels of malondialdehyde (MDA) and myeloperoxidase (MPO) were determined by spectrophotometer; the mRNA expression of tumor necrosis factor-α (TNF-α) and interleukin-1 beta (IL-1β) in the liver were measured by real-time PCR; Dickkopf-1 (DKK-1) and beta-catenin (β-catenin) protein expression in the liver were detected by Western blot. Results: Atfer 2, 6, 24 h reperfusion, compared with the IR group, the liver function (ALT, AST and LDH) in the minocycline group was signiifcantly improved (allP<0.05); the Suzuki’s scores and the levels of hepatic TNF-α and IL-1β mRNA were signiifcantly decreased (allP<0. 05); the MDA and MPO levels the liver were decreased (bothP<0.05); the protein expression of hepatic DKK-1 was decreased (P<0.05), while the protein expression of β-catenin was increased (P<0.05). Conclusion: Minocycline can alleviate the ischemic-reperfusion injury mainly through reducing oxidative stress and inhibiting the release of pro-inlfammatory cytokines depends on the activation of the Wnt/β-catenin signaling pathway in the liver.

ObjectiveTo investigate the surgical procedures of orthotopic small bowel transplantation (SBT) model in mice to study the function and rejection of SBT.MethodsWe established a mouse SBT allograft model as follows: the donor portal vein was anastomosed end by side with the recipient inferior vena cava; the donor superior mesenteric artery with aorta patch was anastomosed end by side with recipient abdominal aorta.After an appropriate length of the recipient's small bowel was removed,the donor's small bowel and the recipient's small bowel were end-to-end anastomosed discontinuously.The mice were fasted for 4 d after the operation,free access to water and subcutaneously injection of 2 mL of 5％ glucose saline twice daily.Operation success was regarded as survival for more than 5 d.There is no antibiotic and immunosuppressor.ResultsA total of 30 transplantations were done,the 5 d survival rate was 60％ ( 18/30),and 12 died within 5 d.Among the dead recipients,5 died of arterial anastomotic stenosis and anastomotic thrombosis,2 of hemorrhagic shock caused by anastomotic bleeding,and the other 5 of intra-abdominal infection caused by postoperative intestinal fistula.The donors' operative time was (40 ± 4.5 ) min,warm ischemia time was about 0.5 min,donor preparation time was about 3 min,and cold preservation time was (30 ±7.5) min.The recipients' operative time was (95 ±8.0) min,among which,the abdominal aorta and inferior vena cava clamping time was ( 38 ± 3.5 ) min,the venous anastomotic time was (10 ±2.0) min and the arterial anastomotic time was (15 ± 3.0) min.The mean intraoperative blood loss of the surviving recipient mice was about 0.2 mL.ConclusionHigh quality vascular anastomosis,and rehydration of donors and recipients are crucial factors for improving the success rate of SBT.