Solid organ transplantation (SOT) is an effective treatment method for various end-stage diseases. However, due to the need for long-term use of immunosuppressive drugs to prevent rejection reactions after the surgery, SOT recipients are generally in a state of low immune function, resulting in a significant increase in the risk of infection. Post-transplant infection, especially infections caused by multi-drug resistant bacteria, is one of the common complications for SOT recipients and is also a major cause of graft dysfunction, graft loss and even death of the recipients. As the global situation of bacterial resistance becomes increasingly severe, the burden of infectious diseases continues to increase, seriously threatening the survival prognosis and graft function of SOT recipients. The exploration of new antibiotic research and rational application strategies worldwide has become crucial. The development and launch of various new antibiotics have provided more options for clinical practice. Therefore, systematically reviewing the drug characteristics of new antibiotics and their application status in this special population of SOT recipients is of great significance for guiding clinical practice and improving patients’ prognosis.

Objective To investigate the distribution characteristics of pathogens causing infections within 90 days after liver transplantation and the influencing factors of infection. Methods Clinical data of 176 recipients who underwent liver transplantation at the Liver Transplant Center of Beijing Friendship Hospital Affiliated to Capital Medical University from September 2021 to August 2024 were retrospectively analyzed. Patients were divided into the infection group (n=124) and the non-infection group (n=52) based on whether they developed infection within 90 days after transplantation. The distribution characteristics of pathogens in infected patients were analyzed. Univariate and multivariate logistic regression analyses were used to explore the influencing factors of infection. Results Among the 176 liver transplant recipients, 124 cases developed 243 episodes of 518 bacterial, fungal, viral or mycoplasma infections within 90 days after transplantation, with an overall infection rate of 70.5% (124/176). The composition of pathogens was mainly Gram-negative bacteria (38.6%, 200/518), followed by Gram-positive bacteria (32.2%, 167/518) and viruses (15.4%, 80/518), and fungi accounted for 13.1% (68/518). Among Gram-negative bacteria, the main pathogen was Klebsiella pneumoniae (6.8%, 35/518), and among Gram-positive bacteria, the main pathogen was Enterococcus faecalis (8.5%, 44/518). Viruses included Epstein-Barr virus (3.7%, 19/518) and cytomegalovirus (3.7%, 19/518), and fungi were mainly Candida albicans (6.8%, 35/518). The most common infection site among the 243 episodes was pulmonary infection (42.0%, 102/243), followed by abdominal infection (22.6%, 55/243) and bloodstream infection (18.1%, 44/243). The infections mainly occurred within 2 weeks after transplantation (60.9%, 148/243). Multivariate logistic regression analysis indicated that preoperative infection within 2 weeks, a high preoperative model for end-stage liver disease (MELD) score, and preoperative sarcopenia were independent risk factors for infection within 90 days after liver transplantation (all odds ratio>1, P<0.05). After multivariate correction, the levels of CD4⁺T cells and CD8⁺T cells within 90 days after surgery were independently associated with the occurrence of infection. Low levels of CD4⁺T cells and CD8⁺T cells might be related to an increased risk of infection. Conclusions The infection rate after liver transplantation is high, and the pathogens are mainly Gram-negative bacteria. The lungs are the most common infection site. Preoperative MELD score, preoperative sarcopenia and preoperative infection within 2 weeks are independent risk factors for infection within 90 days after liver transplantation. Regular monitoring of immune indicators CD4⁺T cells and CD8⁺T cells levels after transplantation is helpful to reduce the occurrence of post-transplantation infection.

Objective To investigate the influence of plasma infusion during orthotopic liver transplantation on the incidence of acute kidney injury (AKI) in recipients. Methods Cinical data of 473 liver transplant recipients who underwent orthotopic liver transplantation at Beijing Chaoyang Hospital Affiliated to Capital Medical University from January 2016 to December 2020 were retrospectively collected. The study included 354 recipients who received plasma infusion during the operation (plasma group) and 119 recipients who did not receive plasma infusion during the operation (control group). Preoperative conditions, donor conditions, intraoperative conditions, main outcome indicators and secondary outcome indicators of the two groups were analyzed and compared. Receiver operating characteristic curve was drawn to calculate the maximum cut-off value of intraoperative plasma infusion volume that affected the occurrence of AKI within 7 days after surgery. Logistic regression analysis was performed to analyze the correlation between intraoperative plasma infusion volume and the incidence of AKI within 7 days after surgery. Results Before propensity score matching, the incidence of AKI within 7 days after surgery and the incidence of grade Ⅲ AKI in the plasma group were higher than those in the control group (both P<0.05). After propensity score matching, 62 recipients were included in each group. There was no statistically significant difference in the incidence of AKI within 7 days after surgery between the plasma group and the control group, but the incidence of grade Ⅲ AKI within 7 days after surgery in the plasma group was higher than that in the control group (P=0.041). Logistic regression analysis showed that intraoperative plasma infusion volume >900 mL was a potential risk factor for AKI within 7 days after surgery (odds ratio=1.936, 95% confidence interval 1.193-3.142, P=0.007). There were no statistically significant differences in the incidence of 365-day postoperative fatality, reperfusion syndrome, and postoperative 30-day complications between the two groups before and after propensity score matching. In addition, the postoperative albumin, fibrinogen levels, and international normalized ratio in the plasma group were better than those in the control group before and after matching (all P<0.05). Conclusions Large amount of intraoperative plasma infusion is associated with an increased risk of grade Ⅲ AKI after orthotopic liver transplantation. Intraoperative plasma infusion volume >900 mL may increase the risk of AKI within 7 days after surgery.

Objective To preliminarily investigate the safety and efficacy of donor pancreas needle biopsy in simultaneous pancreas-kidney transplantation. Methods Clinical data of 7 cases undergoing donor pancreas biopsy were collected retrospectively. All cases underwent donor pancreas biopsy before or during simultaneous pancreas-kidney transplantation. Frozen section or paraffin sectioning techniques were used for tissue preparation, and hematoxylin-eosin and Masson staining were performed to histologically evaluate the donor pancreas. The quality of donor pancreas was comprehensively assessed by combining histological findings with the donor's clinical data. Postoperative follow-up data of 5 simultaneous pancreas-kidney transplant recipients were collected to summarize the safety of donor pancreas biopsy and the prognosis of transplant recipients. Results The 7 pancreas donors were aged 28 to 62 years, with a body mass index ranging from 20.76 to 27.68 kg/m². Liver ultrasound indicated fatty liver in 3 cases, while pancreatic ultrasound did not reveal any significant abnormalities. Among them, biopsy was performed on 2 donors after completion of pancreatic procurement and processing, and the frozen section histology showed moderate acute pancreatitis changes (edema of acinar cells, necrosis and inflammatory cell infiltration). Combined with a serum amylase level elevated more than 3 times the upper limit of normal value, these two donor pancreases were finally discarded. The remaining 5 cases underwent biopsy immediately after pancreatic vascular anastomosis during simultaneous pancreas-kidney transplantation, and histological evaluation was performed on paraffin-embedded sections. No biopsy-related complications (such as bleeding, pancreatic fistula, etc.) occurred after transplantation. One recipient died of severe infection 2 months after transplantation, while the other 4 recipients were followed up for more than 5 years, with well-functioning transplant kidneys and pancreases. Conclusions Donor pancreas biopsy is relatively safe, and the risk of biopsy-related complications after transplantation is controllable. Comprehensive assessment of donor pancreas quality by combining histological evaluation with the donor's clinical indicators is conducive to improving the accuracy of donor pancreas selection and organ utilization.

Organ donation and transplantation in China have developed rapidly, ranking second in the world in terms of both donation and transplantation volume. However, both the quantity and quality of organ transplants remain to be further improved to satisfy the demands of the vast number of recipients awaiting transplantation. Artificial intelligence (AI) facilitates the integration, analysis, and application of multi-source clinical big data. It is capable of assisting in expanding the pool of available donor organs and enhancing graft quality, thereby providing a novel technological foundation for alleviating the imbalance between the supply and demand of transplant organs. To standardize the auxiliary application of AI throughout the entire process of organ donation and transplantation in China, a team of multidisciplinary experts were convened to formulate the Chinese Expert Consensus on AI-Assisted Clinical Decision-Making in Organ Transplantation. By establishing unified requirements for data and models, this consensus forms a technical framework covering clinical scenarios across the entire workflow of organ donation and transplantation, including donor assessment and maintenance, organ matching, organ preservation and transport, transplant surgery, and post-transplant recipient management. Furthermore, it clarifies ethical and regulatory constraints as well as the boundaries of responsibility subjects. The aim is to further enhance the standardization and safety of AI-assisted organ donation and transplantation, ultimately promoting the high-quality development of this field in China.

Pancreas transplantation and simultaneous pancreas-kidney transplantation are the most effective treatments for diabetes, end-stage diabetic nephropathy, or diabetes combined with end-stage renal disease, which have achieved good therapeutic effects in the treatment of type 1 diabetes and some cases of type 2 diabetes. However, acute rejection of transplant pancreas remains one of the important factors affecting the survival of recipients and the transplant pancreas after pancreatic transplantation, and it is a key issue that needs to be urgently addressed. In order to further standardize the clinical diagnosis and treatment of acute rejection of transplant pancreas, experts in organ transplantation, transplantation pathology and immunology from the Branch of Organ Transplantation of Chinese Medical Association organized a joint effort to formulate the "Clinical diagnosis and treatment guidelines for acute rejection of transplant pancreas". The content covers 14 key clinical issues such as acute T-cell mediated rejection of transplant pancreas, acute antibody-mediated rejection, transplant pancreas biopsy, pathological standards, diagnosis and treatment methods. It summarizes 17 evidence-based recommendations. The guideline was developed based on the evidence grading and recommendation strength standards of the Oxford University Evidence-Based Medicine Center's 2009 edition, aiming to guide clinical practice through evidence-based methods, with the goal of improving the diagnosis and treatment level of acute rejection of transplant pancreas in China.

Clinical death refers to the permanent cessation of life functions. This article reviews the definition of clinical death and the various scenarios in which it occurs, classifies the process of clinical death, and discusses the criteria for determining uncontrollable cardiac death, controllable cardiac death and the criteria and workflow for determining brain death. It elaborates on the relationship between brain death and death, and proposes the areas to note when standardizing the medical documentation of death cases. Based on this, it introduces the content of the management system and workflow construction for death determination in medical institutions, including management structure, personnel qualifications, document norms, quality control system and training mechanism. Paying attention to the construction of the management system and workflow for death determination in medical institutions is of great significance for ensuring medical quality and safety, promoting the healthy development of organ donation, and maintaining the seriousness of legal and ethical practices.

The technology of xenogeneic organ transplantation, as one of the core strategies to address the current contradiction between the supply and demand of transplant organs, has achieved significant breakthroughs from basic research to clinical application driven by factors such as the innovation of gene modification technology, the injection of research capital and the expansion of clinical trials, especially with the first actual clinical application of a pig heart-to-human transplant. China is also at the forefront of this field. This article intends to summarize the international research trends of xenogeneic organ transplantation (including financial support, the evolution of research stages and global clinical trial cases), and analyze the evolution and optimization of xenogeneic transplantation immunosuppression schemes, as well as the breakthroughs and unresolved scientific issues in current key clinical application technologies. The aim is to comprehensively present the progress of this field from basic research to clinical transformation, and provide references for promoting the rapid development of China's xenogeneic transplantation technology and subsequent clinical transformation and research directions.

Objective To investigate the role and potential mechanism of secreted phosphoprotein 1 (SPP1)⁺ macrophages in the formation of chronic renal allograft fibrosis. Methods The expression features of SPP1⁺ macrophages in renal allografts of chronic allograft dysfunction (CAD) patients were analyzed based on single-cell transcriptome data of renal tissues from patients with CAD. Transcription factor VIPER analysis and DoRothEA transcription factor activity analysis were performed on the single-cell transcriptome data. Renal tissue samples were collected from kidney transplant recipients, including the CAD group (n=5) and the non-renal allograft fibrosis group (CTL group, n=5). A mouse model of chronic allograft rejection was established and divided into the allogeneic kidney transplantation group (CAD group, n=3) and the syngeneic kidney transplantation group (SYN group, n=3). Hematoxylin-eosin staining was used to detect renal tissue injury in mice, and Masson staining was used to detect renal tissue fibrosis. Immunofluorescence staining was performed to detect SPP1 expression in renal tissues of transplant recipients and mouse renal allografts. Bone marrow-derived macrophages (BMDMs) were extracted from mice and subjected to hypoxia stimulation. The expression of hypoxia-inducible factor (HIF)-1α and SPP1 was detected by Western blot, and SPP1 expression was detected by flow cytometry. BMDMs were transfected with HIF-1α overexpression plasmid and HIF-1α small interfering RNA (siRNA) followed by hypoxia intervention, and the expression of HIF-1α and SPP1 was detected by Western blot. Mouse aortic endothelial cells (MAECs) were co-cultured with the supernatant of BMDMs, and the expression of endothelial-mesenchymal transition (EndMT)-related markers was detected by Western blot and immunofluorescence. Results Single-cell transcriptome analysis showed that the proportion of SPP1⁺ macrophages in renal allograft tissues was significantly higher in the CAD group than in the CTL group (P<0.05). The renal injury score and the percentage of interstitial fibrotic area in the CAD group were significantly higher than those in the SYN group (both P<0.05). Immunofluorescence staining showed that the proportion of SPP1⁺ macrophages was increased in the CAD group compared with the CTL group, and also increased in the CAD group compared with the SYN group (both P<0.05). VIPER analysis and DoRothEA transcription factor activity analysis revealed activation of the hypoxia pathway and upregulated expression of transcription factors such as HIF-1α in SPP1⁺ macrophages. SPP1 expression was elevated in BMDMs under hypoxic conditions. Knockdown of HIF-1α inhibited hypoxia-induced SPP1 protein expression, whereas overexpression of HIF-1α upregulated SPP1 protein levels. After co-culture of hypoxia-induced BMDMs with MAECs, the expression levels of EndMT-related markers were increased. Conclusions SPP1⁺ macrophages differentiated under hypoxia are significantly infiltrated in the formation of chronic renal allograft fibrosis, and may promote renal allograft fibrosis by inducing EndMT in renal vascular endothelial cells.

Objective To evaluate the safety and efficacy of a self-developed micro-normothermic machine perfusion (NMP) system (micro-perfusion device) for preserving isolated porcine limbs. Methods Five healthy Landrace pigs were selected, and their left and right forelimbs were randomly divided into the NMP group and static cold storage (SCS) group. The NMP group was perfused with the self-developed micro-perfusion device and polymerized hemoglobin perfusate for 32 hours at normothermia, while the SCS group was preserved at 4 ℃. Hemodynamic parameters such as perfusion pressure and flow were monitored. The pH value, partial pressure of oxygen (PO₂), lactic acid (Lac), creatine kinase (CK) and lactate dehydrogenase (LDH) in the perfusate were measured. Hematoxylin-eosin staining was used to assess the muscle tissue structure, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling was employed to evaluate muscle cell apoptosis, and immunohistochemistry staining was applied to detect the expressions of tumor necrosis factor (TNF)-α and interleukin (IL)-6. A mixed-effects model was used to analyze the effects of time and treatment methods on tissue structure, cell apoptosis and inflammatory factors. Results The device could stably maintain a perfusion pressure of (69±15) mmHg and a flow rate of (117±42) mL/min. The pH value and electrolytes of the perfusate were generally stable, with PO₂ maintained at a high level. Lac was maintained at 5.38(3.81, 6.45) mmol/L, while CK and LDH increased over time. After 32 hours of perfusion in the NMP group, both the myocyte spacing and apoptosis rate were better than those in the SCS group. Mixed-effects model analysis showed that there were statistically significant differences in the effects of NMP treatment and SCS treatment on myocyte spacing and apoptosis rate per unit time (both P < 0.05). There were no statistically significant differences in TNF-α and IL-6 between the two groups, and mixed-effects model analysis showed no statistically significant differences in the effects of NMP treatment and SCS treatment on TNF-α and IL-6 per unit time (both P > 0.05). Conclusions The micro-perfusion device used in this study may achieve 32-hour normothermic preservation in a porcine limb amputation model, maintain basic metabolism and ionic homeostasis, reduce muscle structural damage and cell apoptosis without inducing additional inflammatory responses. This technology is expected to significantly extend the time window for replantation of amputated limbs in disaster rescue and long-distance transportation, providing an important technical basis for clinical translation and subsequent replantation research.