Objective To explore the feasibility and reference value of allogeneic lung transplantation and postoperative monitoring in miniature pigs for lung transplantation research. Methods Two miniature pigs (R1 and R2) underwent left lung allogeneic transplantation. Complement-dependent cytotoxicity tests and blood cross-matching were performed before surgery. The main operative times and partial pressure of arterial oxygen (PaO₂) after opening the pulmonary artery were recorded during surgery. Postoperatively, routine blood tests, biochemical blood indicators and inflammatory factors were detected, and pathological examinations of multiple organs were conducted. Results The complement-dependent cytotoxicity test showed that the survival rate of lymphocytes between donors and recipients was 42.5%-47.3%, and no agglutination reaction occurred in the cross-matching. The first warm ischemia times of D1 and D2 were 17 min and 10 min, respectively, and the cold ischemia times were 246 min and 216 min, respectively. Ultimately, R1 and R2 survived for 1.5 h and 104 h, respectively. Postoperatively, in R1, albumin (ALB) and globulin (GLB) decreased, and alanine aminotransferase increased; in R2, ALB, GLB and aspartate aminotransferase all increased. Urea nitrogen and serum creatinine increased in both recipients. Pathological results showed that in R1, the transplanted lung had partial consolidation with inflammatory cell infiltration, and multiple organs were congested and damaged. In R2, the transplanted lung had severe necrosis with fibrosis, and multiple organs had mild to moderate damage. The expression levels of interleukin-1β and interleukin-6 increased in the transplanted lungs. Conclusions The allogeneic lung transplantation model in miniature pigs may systematically evaluate immunological compatibility, intraoperative function and postoperative organ damage. The data obtained may provide technical references for subsequent lung transplantation research.

Xenotransplantation is an important approach to addressing the shortage of donor organs. However, it still faces numerous challenges, such as acute rejection and zoonotic diseases. Organoid-on-a-chip technology refers to a microcell culture device that simulates the physiological functions of human organs in vitro. In recent years, it has achieved a series of important results in the field of allotransplantation and has great application prospects in the field of xenotransplantation, bringing new opportunities for xenotransplantation research. Therefore, this article discusses the current research status and progress of organoid-on-a-chip technology, combined with the various problems faced by xenotransplantation, to explore the application of organoid-on-a-chip technology in solving the selection of immunosuppressive regimens, matching and viral reactivation in xenotransplantation. This aims to open up new avenues for solving the current problems in the field of xenotransplantation and promote its further development.

Objective To explore the construction of α-1,3-galactosyltransferase (GGTA1) gene-knockout (GTKO) Diannan miniature pigs and the kidney xenotransplantation from pigs to rhesus macaques, and to assess the effectiveness of GTKO pigs. Methods The GTKO Diannan miniature pigs were constructed using the CRISPR/Cas9 gene-editing system and somatic cell cloning technology. The phenotype of GTKO pigs was verified through polymerase chain reaction, Sanger sequencing and immunofluorescence staining. Flow cytometry was used to detect antigen-antibody (IgM) binding and complement-dependent cytotoxicity. Kidney xenotransplantation was performed from GTKO pigs to rhesus macaques. The humoral immunity, cellular immunity, coagulation and physiological indicators of the recipient monkeys were monitored. The function and pathological changes of the transplanted kidneys were analyzed using ultrasonography, hematoxylin-eosin staining, immunohistochemical staining and immunofluorescence staining. Results Single-guide RNA (sgRNA) targeting exon 4 of the GGTA1 gene in Diannan miniature pigs was designed. The pGL3-GGTA1-sgRNA1-GFP vector was transfected into fetal fibroblasts of Diannan miniature pigs. After puromycin selection, two cell clones, C59# and C89#, were identified as GGTA1 gene-knockout clones. These clones were expanded to form cell lines, which were used as donor cells for somatic cell nuclear transfer. The reconstructed embryos were transferred into the oviducts of trihybrid surrogate sows, resulting in 13 fetal pigs. Among them, fetuses F04 and F11 exhibited biallelic mutations in the GGTA1 gene, and F04 had a normal karyotype. Using this GTKO fetal pig for recloning and transferring the reconstructed embryos into the oviducts of trihybrid surrogate sows, seven surviving piglets were obtained, all of which did not express α-Gal epitope. The binding of IgM from the serum of rhesus monkey 20# to GTKO pig PBMC was reduced, and the survival rate of GTKO pig PBMC in the complement-dependent cytotoxicity assay was higher than that of wild-type pig. GTKO pig kidneys were harvested and perfused until completely white. After the left kidney of the recipient monkey was removed, the pig kidney was heterotopically transplanted. Following vascular anastomosis and blood flow restoration, the pig kidney rapidly turned pink without hyperacute rejection (HAR). Urine appeared in the ureter 6 minutes later, indicating successful kidney transplantation. The right kidney of the recipient was then removed. Seven days after transplantation, the transplanted kidney had good blood flow, the recipient monkey's serum creatinine level was stable, and serum potassium and cystatin C levels were effectively controlled, although they increased 10 days after transplantation. Seven days after transplantation, the levels of white blood cells, lymphocytes, monocytes and eosinophils in the recipient monkey increased, while platelet count and fibrinogen levels decreased. The activated partial thromboplastin time, thrombin time and prothrombin time remained relatively stable but later showed an upward trend. The recipient monkey survived for 10 days. At autopsy, the transplanted kidney was found to be congested, swollen and necrotic, with a small amount of IgG deposition in the renal tissue, and a large amount of IgM, complement C3c and C4d deposition, as well as CD68⁺ macrophage infiltration. Conclusions The kidneys of GTKO Diannan miniature pigs may maintain normal renal function for a certain period in rhesus macaques and effectively overcome HAR, confirming the effectiveness of GTKO pigs for xenotransplantation.

Objective To establish a technical system for allogeneic kidney transplantation surgery in pigs using the Banna miniature pig inbred strain,and to evaluate it through routine blood tests,liver and kidney function tests,thus providing reference data for the preparation of allogeneic kidney transplantation models.Methods A total of 4 cases of allogeneic kidney transplantation surgeries were performed,including 1 case of single kidney transplantation in a healthy pig,2 cases of kidney transplantation after unilateral nephrectomy,and 1 case of kidney transplantation after bilateral nephrectomy.Before kidney transplantation,cross-matching and complement-dependent cytotoxicity(CDC)tests were used for matching between donor and recipient pigs.After kidney transplantation,peripheral blood samples were regularly collected from pigs for routine blood tests,liver function tests,and kidney function tests,and color Doppler ultrasound technology was used to detect blood supply to the transplanted kidneys.After reaching the experimental endpoint,both kidneys of pig DR1 and the left kidney of pig DR3 were collected and hematoxylin-eosin(HE)staining was performed to evaluate pathological changes in the transplanted kidneys.Results Recipient pigs DR1 and DR3 died at 17 days and 30 days after surgery respectively,while recipient pigs R and DR2 remained in good condition during the 30-day observation period.The results of liver and kidney function test showed that in pig DR1,alanine aminotransferase(ALT)levels increased on postoperative day 1(＞1 000 U/L),peaked on postoperative day 7(1 300 U/L),and aspartate aminotransferase(AST)levels peaked on postoperative day 1(＞3 000 U/L).On postoperative day 17,ALT and AST levels remained high(ALT,500 U/L;AST,700 U/L).In pigs R,DR2,and DR3,ALT and AST levels returned to normal around day 17.Serum creatinine(Crea)levels in pig R remained stable without postoperative increase.Crea levels in pigs DR1 and DR2 showed transient elevation on postoperative day 1,then gradually returned to normal(＜100 μmol/L).Crea levels in pig DR3 remained below 500 μmol/L from postoperative days 2-10,but increased between days 11-28,reaching up to 1 500 μmol/L,indicating gradual loss of kidney function.Ultrasound results showed that the preoperative resistive index(RI)of recipient pig R was 0.91.On postoperative day 24,renal cortex and medulla showed abundant blood flow signals with RI value of 0.88,which was close to the pre-transplantation RI value.For pig DR2,the RI value on postoperative day 17 was 0.89,with poor renal cortex blood flow and relatively good renal medulla blood flow.In pig DR1 on postoperative day 17,no blood flow signals were detected in the transplanted kidney.HE staining results showed that the non-transplanted healthy right kidney of pig DR1 had normal structure,while the transplanted left kidney showed blurred glomerular structure and nuclear dissolution,indicating that the left kidney had lost function before removal.In the transplanted left kidney of pig DR3,large numbers of red blood cells and lymphocyte infiltration were observed in glomeruli and renal tubules,indicating possible coagulation dysfunction and rejection reactions after kidney transplantation.Conclusion Banna miniature pig inbred strain is used as experimental animals to perform four cases of allogeneic pig-to-pig kidney transplantation.The physiological parameters of the recipient pig and the function of the transplanted kidney are monitored after surgery using routine blood tests,liver and kidney function tests,color Doppler ultrasound,and pathological examinations.The allogeneic pig-to-pig kidney transplantation technical system established in the study can provide a foundation for clinicians to conduct kidney transplantation surgeries.

Objective To establish a method for acquisition, perfusion, preservation and transportation of the genetically modified pig kidneys. Methods An eight genetically modified pig was utilized as experimental subject. Prior to kidneys procurement, the health status of the pig was assessed through hematology examination, and the vascular structure of the kidneys was examined using imaging techniques. Following kidneys acquisition, the pig kidneys were perfused and subsequently packaged into the cryogenic storage container labeled "For Organ Transportation Only" for interprovincial transport after communicating the transportation process with transportation department. To evaluate pathological damage to the pig kidneys, a serious of methods were employed such as hematoxylin-eosin (HE) staining, real-time fluorescent quantitative polymerase chain reaction (RT-qPCR), terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) fluorescence staining and enzyme-linked immune absorbent assay (ELISA). Results The preoperative examination of the eight genetically modified pig showed that the serum creatinine was 73.2 μmol/L, blood urea nitrogen was 2.8 mmol/L and hemoglobin was 116 g/L, all within the normal range, indicating normal renal function. CT angiography revealed no lesions in the pig kidneys, and no dilation, stenosis or premature branching of the blood vessels. The total time of obtaining the left and right kidneys from the eight genetically modified pig was (125 ± 10) min, with a blood loss of (20 ± 2) mL. The warm ischemia times were 3 min and 7 min, respectively. The perfusion and trimming times of the left and right kidneys were 36 min and 41 min, respectively. After perfusion, both kidneys were white and moist. The cold preservation and transportation time was 8 h. HE staining showed that some glomeruli were shrunk, and the lumens of the surrounding renal tubules were slightly depressed and swollen with partial inner membrane shedding and microvacuoles formed when the kidneys were preserved for 8 h. The level of cysteinyl aspartate-specific proteinase-3 messenger RNA in the kidneys tissue gradually increased with the extension of cold preservation time after 2 h (P<0.05). TUNEL fluorescence staining showed that only a small number of cells underwent apoptosis after 8 h of cold preservation, which was not significantly different from that at 0 h (P>0.05). ELISA results showed that the contents of lactate dehydrogenase (LDH) and creatinine in the preservation solution remained relatively stable, but the content of kidney injury molecule 1 (KIM-1) gradually increased with the extension of preservation time, suggesting that the pig kidneys had mild injury. Conclusions By establishing methods for acquisition, perfusion, preservation and transportation of the kidneys from genetically modified donor pig, it is possible to effectively and reliably use genetically modified pig kidneys for xenotransplantation.

Objective To develop GTKO (α-1,3-galactosyltransferase gene-knockout, GTKO)/hCD55 (human CD55) gene-edited xenotransplant donor pigs and verify their function. Methods In this study, CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 (CRISPR-associated nuclease 9), PiggyBac transposon technology and somatic cell nuclear transfer technology were used to construct GTKO/hCD55 gene-edited Diannan miniature pigs. The phenotype and function of GTKO/hCD55 pigs were analyzed by Sanger sequencing, real-time fluorescence quantitative PCR, flow cytometry, immunofluorescence, bisulfite sequencing, antigen-antibody binding assays, and complement-dependent cytotoxicity assays. Results After transfection of PX458 and PiggyBac gene editing vectors into wild-type fetal pig fibroblasts, 48 single-cell colonies were obtained through puromycin drug screening. Two single-cell colonies were selected for somatic cell nuclear transfer, resulting in two fetal pigs at 33 days of gestation. The GGTA1(α-1,3-galactosyltransferase) genotypes of fetal pig F01 were -17 bp and wild type (WT), while the GGTA1 genotypes of fetal pig F02 were -26 bp/+2 bp and -3 bp. The hCD55 mRNA expression levels of both fetal pigs were significantly higher than those of WT pigs (P＜0.01). The fetal pig F02 was selected as the donor cell source for recloning, 11 surviving piglets were obtained, all identified as GTKO/hCD55 gene-edited pigs. These pigs showed absence of α-Gal antigen expression, but weak or no expression of hCD55 was observed. Methylation analysis of the hCD55 gene's CpG island showed hypermethylation in kidney tissue lacking hCD55 expression, whereas it was not methylated or partially methylated in kidney tissue expressing hCD55. Moreover, codon optimization of the CpG island of the hCD55 gene to reduce CG content could achieve stable expression of the hCD55 gene. In addition, antigen-antibody binding experiment showed that the amount of human IgM binding to GTKO/hCD55 gene-edited pig fibroblasts was significantly lower than that of WT pigs (P＜0.01). Complement-dependent cytotoxicity experiment showed that the survival rate of fibroblasts in GTKO/hCD55 pigs was significantly higher than that in WT pigs (P＜0.01). Conclusion This study demonstrates the successful generation of GTKO/hCD55 gene-edited xenotransplant donor pigs. Methylation-induced gene silencing of the hCD55 gene can be effectively avoided by reducing the CG content of the CpG island through codon optimization. This study provides a reference for the development of xenotransplant donor pigs and guides subsequent research on xenotransplantation.

Lung transplantation is the ultimate therapeutic option for end-stage pulmonary diseases such as interstitial pneumonia, chronic obstructive pulmonary disease and pneumoconiosis. Currently, the shortage of allogeneic lung donors significantly limits the opportunity for end-stage lung disease patients to receive lung transplantation. In recent years, with the rapid development of biomedical engineering technologies, especially the major breakthroughs in genetic modification and cloning, xenogeneic lung transplantation has shown important potential for clinical translation. Among them, genetically modified pigs have become the most promising xenogeneic lung source due to the close similarity of organ size and physiological characteristics to humans, and the ability to perform targeted gene knockouts (such as α-Gal antigen knockout) to reduce the occurrence of hyperacute rejection. This article focuses on the research progress of porcine xenogeneic lung transplantation, systematically reviews the latest achievements and challenges in animal experiments and human trials, and introduces the technical experience accumulated by Shenzhen Third People's Hospital in the porcine-to-monkey xenogeneic lung transplantation model, in the hope of providing practical references for future research in this field.

Objective To establish a technical system for allogeneic kidney transplantation surgery in pigs using the Banna miniature pig inbred strain,and to evaluate it through routine blood tests,liver and kidney function tests,thus providing reference data for the preparation of allogeneic kidney transplantation models.Methods A total of 4 cases of allogeneic kidney transplantation surgeries were performed,including 1 case of single kidney transplantation in a healthy pig,2 cases of kidney transplantation after unilateral nephrectomy,and 1 case of kidney transplantation after bilateral nephrectomy.Before kidney transplantation,cross-matching and complement-dependent cytotoxicity(CDC)tests were used for matching between donor and recipient pigs.After kidney transplantation,peripheral blood samples were regularly collected from pigs for routine blood tests,liver function tests,and kidney function tests,and color Doppler ultrasound technology was used to detect blood supply to the transplanted kidneys.After reaching the experimental endpoint,both kidneys of pig DR1 and the left kidney of pig DR3 were collected and hematoxylin-eosin(HE)staining was performed to evaluate pathological changes in the transplanted kidneys.Results Recipient pigs DR1 and DR3 died at 17 days and 30 days after surgery respectively,while recipient pigs R and DR2 remained in good condition during the 30-day observation period.The results of liver and kidney function test showed that in pig DR1,alanine aminotransferase(ALT)levels increased on postoperative day 1(＞1 000 U/L),peaked on postoperative day 7(1 300 U/L),and aspartate aminotransferase(AST)levels peaked on postoperative day 1(＞3 000 U/L).On postoperative day 17,ALT and AST levels remained high(ALT,500 U/L;AST,700 U/L).In pigs R,DR2,and DR3,ALT and AST levels returned to normal around day 17.Serum creatinine(Crea)levels in pig R remained stable without postoperative increase.Crea levels in pigs DR1 and DR2 showed transient elevation on postoperative day 1,then gradually returned to normal(＜100 μmol/L).Crea levels in pig DR3 remained below 500 μmol/L from postoperative days 2-10,but increased between days 11-28,reaching up to 1 500 μmol/L,indicating gradual loss of kidney function.Ultrasound results showed that the preoperative resistive index(RI)of recipient pig R was 0.91.On postoperative day 24,renal cortex and medulla showed abundant blood flow signals with RI value of 0.88,which was close to the pre-transplantation RI value.For pig DR2,the RI value on postoperative day 17 was 0.89,with poor renal cortex blood flow and relatively good renal medulla blood flow.In pig DR1 on postoperative day 17,no blood flow signals were detected in the transplanted kidney.HE staining results showed that the non-transplanted healthy right kidney of pig DR1 had normal structure,while the transplanted left kidney showed blurred glomerular structure and nuclear dissolution,indicating that the left kidney had lost function before removal.In the transplanted left kidney of pig DR3,large numbers of red blood cells and lymphocyte infiltration were observed in glomeruli and renal tubules,indicating possible coagulation dysfunction and rejection reactions after kidney transplantation.Conclusion Banna miniature pig inbred strain is used as experimental animals to perform four cases of allogeneic pig-to-pig kidney transplantation.The physiological parameters of the recipient pig and the function of the transplanted kidney are monitored after surgery using routine blood tests,liver and kidney function tests,color Doppler ultrasound,and pathological examinations.The allogeneic pig-to-pig kidney transplantation technical system established in the study can provide a foundation for clinicians to conduct kidney transplantation surgeries.

Effective preoperative matching of organ transplantation is essential for the success of organ transplantation.The current methods of preoperative matching for xenotransplantation are derived from human allogeneic organ transplantation.However,these methods are simple and cannot accurately predict whether rejection will occur after transplantation.A noteworthy feature of xenotransplantation lies in the stability of the donor source and the clarity of its genotype,which facilitate convenient sampling and ensure robust repeatability.The multi-link and multi-dimensional preoperative matching is conducive to accurately screening suitable donors and reducing the occurrence of postoperative rejection after xenotransplantation,including making full use of the advantages of donor control in xenotransplantation,expanding tissue level matching methods on the basis of improving traditional cytological matching,paying attention to the role of endothelial cells in matching,and developing organic-level matching methods.Therefore,this article reviews the methods of allogeneic organ transplantation matching,current methods,existing problems and possible breakthroughs of xenotransplantation matching,in order to provide reference for further research on xenotransplantation matching.

Objective To construct a Type 1 diabetes model in miniature pigs and explore postoperative care strategies for effectively prolonging the survival time of the model pigs.Methods Seven Banna miniature pigs were selected for pancreatectomy.Glucose,vitamins,and antibiotics were administered for 3-5 days after surgery to aid recovery.Blood glucose and urine glucose levels were measured twice a day in the morning and evening to adjust insulin supplementation accordingly.The model pigs were observed daily and records were kept,including orexis,psychosis,weakness,skin ulcer,and feces and urine.Body weight was measured weekly until the death of the model animals.Based on the model pigs'condition,glucose injection and Ringer's lactate solution were administered to supplement nutrition and correct electrolyte imbalances.Results All seven Banna miniature pigs showed typical symptoms of diabetes:random blood glucose levels higher than 11.1 mmol/L after pancreatectomy,far exceeding the average blood glucose level of 6.0 mmol/L in normal pigs;positive urine glucose;and progressive weight loss.These features indicated the successful construction of Type 1 diabetes model.Additionally,Type 1 diabetic pigs that survived more than 8 weeks showed progressive hair loss and skin ulceration.Euthanasia was performed on model pigs when they were unable to stand or even eat independently,and pathological examination and HE staining were conducted on tissues collected from affected organs such as the liver,kidneys,and skin.Pathological sections revealed liver congestion,massive glycogen accumulation,ballooning degeneration of hepatocytes,and progressive liver fibrosis,along with glomerular congestion,vacuolar degeneration in renal tubular epithelial cells,proteinuria,dermal congestion,thinning of vascular walls,and varying degrees of parakeratosis and dyskeratosis in the liver,kidneys,and skin tissues due to prolonged hyperglycemia.The average survival time of the constructed Banna miniature pig diabetes model was 44 d,with a maximum survival time of 121 d.Conclusion Type 1 diabetes model can be constructed successfully in Banna miniature pigs through pancreatectomy.With meticulous postoperative care,a long-term Type 1 diabetes model with significant complications can be achieved,providing a stable large-animal model for Type 1 diabetes treatment strategies.