As a pivotal strategy to alleviate the shortage of organ donors, xenotransplantation has achieved remarkable advances in both pre-clinical and clinical studies in recent years, driven by continuous optimization of gene modification techniques and immunosuppressive regimens. Nevertheless, clinical translation still confronts formidable challenges, including rejection and heightened infection risks, which severely compromise long-term graft survival. Consequently, the role of immunosuppressive regimens in xenotransplantation has become increasingly prominent. This article summarizes the mechanisms underlying xenogeneic immune rejection, the latest developments in immunosuppressive regimens, cutting-edge strategies for inducing immune tolerance and the major hurdles facing clinical xenotransplantation. It delves into potential optimization strategies and directions for future clinical research, aiming to offer theoretical insights and practical guidance for the safe and effective application of clinical xenotransplantation.

BACKGROUND:At present,there are few reports on the postoperative efficacy of arthroscopic coracoid tunnel-free suspension fixation and coracoid single tunnel fixation in the treatment of acromioclavicular joint dislocation at home and abroad.The specific clinical efficacy of the two procedures and whether there are other risks need to be explored. OBJECTIVE:To compare the short-term postoperative clinical efficacy of arthroscopic TightRope band plate fixation with single tunnel fixation of the coracoid process and tunnel-free suspension fixation of the coracoid process in the treatment of acute type Ⅲ-Ⅴ acromioclavicular joint dislocation. METHODS:A retrospective analysis was performed in 45 patients with acromioclavicular joint dislocation who met the inclusion criteria admitted to the Sixth Affiliated Hospital of Xinjiang Medical University from June 2019 to September 2022,and were divided into coracoid single tunnel fixation group(20 cases)and coracoid tunnel-free suspension fixation group(25 cases)according to the surgical treatment plan.Operation time,incision length,blood loss,Constant-Murley score,visual analogue scale score,the American Shoulder and Elbow Surgeons(ASES)score and intraoperative and postoperative complications of the shoulder joint before operation,3 months after surgery and the last follow-up were compared between the two groups. RESULTS AND CONCLUSION:All patients successfully completed the operation,and there was no important nerve or blood vessel damage during the operation.The operation time of the coracoid tunnel-free suspension fixation group was significantly shorter than that of the coracoid tunnel-free suspension fixation group(P<0.05).There was no significant difference in intraoperative blood loss and incision length between the two groups(P>0.05).All patients were followed up for 12 to 24 months,with an average of(15.29±2.73)months.In the coracoid single tunnel fixation group,at 3 months after operation and the final follow-up,the visual analogue scale score was significantly lower than the preoperative score(P<0.05);Constant-Murley score and ASES score were significantly increased compared with the preoperative values(P<0.05).In the coracoid tunnel-free suspension fixation group,at 3 months after operation and the final follow-up,the visual analogue scale score was significantly lower than the preoperative score(P<0.05);the Constant-Murley score and the ASES score were both significantly higher than the preoperative scores(P<0.05).At 3 months after operation,the Constant-Murley score of the coracoid tunnel-free suspension fixation group was higher than that of the coracoid single tunnel fixation group(P<0.05),while there was no significant difference in visual analogue scale and ASES scores between the two groups(P>0.05).There was also no significant difference in the visual analogue scale,Constant-Murley,and ASES scores between the two groups at the corresponding time points before surgery and at the final follow-up(P>0.05).Intraoperative and postoperative complications:In the coracoid single tunnel fixation group,there was one case of coracoid cortical rupture and fracture during the tunnel drilling during the operation,and one case of a loss of reduction at 3 months after operation,which was repositioned and fixed with hook plate transposition of the coracoacromial ligament.All patients had good acromioclavicular joint function recovery and no re-dislocation at the final follow-up.All patients in the coracoid tunnel-free suspension fixation group did not suffer from coracoid fractures,loss of reduction and other complications during surgery,postoperatively and at the last follow-up.To conclude,these two arthroscopic treatments for acute type Ⅲ-Ⅴ acromioclavicular joint dislocation have the advantages of less trauma,reliable reduction and fixation,and good recovery of shoulder joint function after operation.However,compared with the coracoid single tunnel technique,the coracoid tunnel-free suspension fixation requires shorter time,faster recovery of shoulder joint function in the short term,and avoids the establishment of bone tunnels on the coracoid process,which reduces the probability of iatrogenic fracture of the coracoid process during operation and provides a higher degree of safety.

Objective To introduce the modeling method of pendulum-like modified rat abdominal heart heterotopic transplantation model and evaluate the quality of the model. Methods An operator without transplantation experience performed 15 consecutive models, recorded the time of each step, changes in body weight and modified Stanford scores, and calculated the surgical success rate, postoperative 1-week survival rate and technical success rate. Ultrasound examinations was performed in 1 week postoperatively. Results The times for donor heart acquisition, donor heart processing, recipient preparation and transplantation anastomosis were (14.3±1.4) min, (3.5±0.6) min, (13.6±2.1) min and (38.3±5.2) min respectively. The surgical success rate was 87% (13/15), and the survival rate 1 week after operative was 100% (13/13). The improved Stanford score indicated a technical success rate of 92% (12/13), and the postoperative 1-week ultrasound examination showed that grafts with Stanford scores ≥3 had detectable pulsation and blood flow signals. Conclusions The pendulum-like modified rat abdominal heart heterotopic transplantation improved model further optimizes the operational steps with a high success rate and stable quality, may be chosen as a modeling option for basic research in heart transplantation in the future.

Xenotransplantation is one of the effective ways to overcome the shortage of donor organs. However, the molecular incompatibility between xenotransplantation donors and recipients can cause rejection, which greatly limits the clinical application of xenotransplantation. In recent years, researchers have deeply explored the mechanism of xenotransplantation rejection through xenotransplantation models of pig-to-monkey and pig-to-brain death recipients, and found that the innate immune system plays an important role in rejection. Macrophages, as phagocytes in the innate immune system, not only damage xenografts through phagocytosis but also interact with other immune cells to influence the immune microenvironment of xenotransplantation. However, due to the heterogeneity of macrophages, their phenotypes and functions in xenotransplantation rejection remain unclear. Therefore, it is necessary to further explore the role of macrophages in xenotransplantation rejection. This article reviews the latest research progress of macrophages in xenotransplantation rejection, aiming to explore the mechanisms of macrophages in xenotransplantation rejection and provide references for future research.

Hypercoagulable state (HCS) after kidney transplantation is one of the common and serious complications in kidney transplant recipients, which has attracted increasing attention in recent years. HCS refers to the abnormal and excessive activation of blood coagulation function, leading to the increased risk of thrombosis. After kidney transplantation, the combined effects of hemodynamic changes, surgical trauma and severe rejection increase the incidence of HCS, not only raising the risk of thrombosis but also potentially causing graft failure and affecting the postoperative survival rate of patients. This article reviews the influencing factors, clinical manifestations, diagnostic methods and preventive strategies of HCS after kidney transplantation, aiming to provide a theoretical basis for optimizing perioperative management and improving the prognosis of patients.

Organ transplantation faces the challenge of a shortage of donors. Although xenotransplantation holds great potential, it is limited by rejection. Extracellular histones, as key members of damage-associated molecular patterns, have been proven in recent years to play a crucial role in transplant rejection by activating innate immunity, regulating the coagulation-inflammation network, and modulating adaptive immune responses. However, the specific functions and key mechanisms remain to be clarified. Therefore, this article reviews the structural characteristics of histones, their release pathways, the biological functions of extracellular histones, and their potential roles in xenotransplantation. It summarizes the latest research progress of extracellular histones in xenotransplantation, analyzes the shortcomings of existing research and the direction for future research, with the expectation of providing references for the application of extracellular histones in xenogeneic kidney transplantation.

Xenotransplantation is an efficient pathway to solve the problem of transplant organ source deficiency in clinical settings. With the increasing progress of gene editing technique and immune suppression regimen, important development has been achieved on researches regarding pig to non-human primate kidney xenotransplantation, which provides a good condition for the introduction of the technique in the clinical application. In view of the substantial difference between human and non-human primate, and to meet the needs of current ethic requirements, it is necessary to perform subclinical studies for pig to human kidney xenotransplantation. In recent years, such subclinical studies with regard to the genetically modified pig to brain death recipient kidney xenotransplantation had been performed, indicating that kidney xenotransplantation gradually began to transit to the clinical development stage. However, donor/recipient selection and immune suppression regimen has not reached a consensus yet, and has to be clarified in subclinical studies. In this article, the current status and confronted problems of donor/recipient selection, immune suppression regimen and post transplantation management in the subclinical studies of kidney xenotransplantation were reviewed, aiming to promote the clinical transformation of kidney xenotransplantation to the clinical application.

Objective To investigate the dynamics of NK cells and Treg cells,as well as their potential prognostic significance in relation to TKI discontinuation among patients diagnosed with chronic myeloid leukemia(CML).Methods In this study,a total of 200 patients diagnosed with CML were randomly selected and divided into two groups:the discontinuation group(n=100)and the non-discontinuation group(n=100).Within the discontinuation group,patients were further categorized into a recurrence subgroup(n=41)and a non-recurrence subgroup(n=59).Clinical data and follow-up information of these patients were retrospectively analyzed.Logistic regression analysis was performed to investigate the impact of various variables on patient outcomes following drug discontinuation,as well as to explore independent factors influencing recurrence in these individuals.Receiver operating characteristic(ROC)curve analysis was employed to assess the predictive value of NK cells and Treg cells for TKI discontinuation outcomes.A significance level of P<0.05 was considered statistically significant.Results The proportion of patients treated with interferon in the discontinuation group was significantly higher than that in the non-discontinuation group(P<0.05).Moreover,the former group exhibited a significantly higher number of NK cells(P<0.05)and Treg cells(P<0.01)compared to the latter group.Compared to the recurrence group,there was a significant increase in the proportion of patients using interferon in the non-recurrence group(P<0.05),along with longer durations of TKI treatment and deep molecular response(DMR)duration(P<0.05).The number of NK cells and Treg cells in the non-recurrence group was significantly higher than that in the recurrence group(P<0.01).Logistic regression analysis found that the use of interferon(OR=1.25,95%CI:1.11～2.03,P<0.001),duration of DMR(OR=1.16,95%CI:1.08～1.92,P<0.05),NK cells(OR=1.64,95%CI:1.14～2.28,P<0.01),and Treg cells(OR=1.83,95%CI:1.15～2.42,P<0.01)were all influencing factors for the recurrence of patients after drug discontinuation.The results of ROC curve analysis showed that the AUC of NK cells combined with Treg cells for predicting the recurrence of TKI after discontinuation was 0.892(95%CI:0.857～0.927,P<0.001).Conclusion The frequencies of NK cells and Treg cells were significantly elevated in patients who remained recurrence-free following TKI discontinuation,highlighting the potential predictive value of combined NK cell and Treg cell analysis for drug cessation in CML patients.

Objective To establish a novel clinical application process of the optical surface monitoring system(OSMS)guided volumetric modulated arc therapy(VMAT)for total body irradiation(TBI),and to assess the accuracy and effectiveness of OSMS in inter-fractional auxiliary positioning before radiotherapy and real-time monitoring of intra-fractional motion during radiotherapy.Methods A retrospective analysis was conducted on 15 leukemia patients who underwent OSMS-guided VMAT-TBI before hematopoietic stem cell transplantation.CT simulation positioning was performed,and the whole-body image data which were collected in head-first supine position(HFS)and feet-first supine position(FFS)were transmitted to the treatment planning system for image registration,multicenter VMAT planning and dose verification.The prescription dose was 800 cGy in 4 fractions twice daily.OSMS was used to assist positioning before delivery,and CBCT was used for position verification.During treatment,OSMS was used for monitoring.The intra-fractional error monitored by OSMS in real time was obtained by analyzing the offline log files.Results The mean dose and coverage of the target area in HFS plan were(905.4±19.0)cGy and 93.0%±2.8%.The mean doses to lung and kidney were(603.7±55.7)cGy and(600.4±49.6)cGy,respectively,and the maximum dose to the lens was(393.9±58.9)cGy.The mean dose and coverage of the target area in FFS plan were(888.5±58.9)cGy and 94.0%±3.2%;and the maximum dose at the junction was(1148.9±72.9)cGy.Fractional treatment delivery time was(75.1±15.1)min.OSMS-assisted positioning was carried out before delivery,and the total deviations of CBCT three-dimensional vector in translational and rotation directions were(2.71±1.96)mm and 0.91°±0.90°,respectively.The three-dimensional vector deviation of the intra-fractional motion amplitude in translational direction monitored by OSMS during the treatment was(1.95±1.88)mm,of which the deviation within 1 mm accounted for 57.5%,79.7%and 62.1%in longitudinal,lateral and vertical directions,respectively.The three-dimensional vector deviation in rotation direction was 0.76°±0.72°,of which the deviation within 1°accounted for 93.1%,85.7%and 94.3%in rotation,pitch and roll directions,respectively.Conclusion VMAT simplifies TBI process,while improving target coverage and organs-at-risk sparing.The use of OSMS can reduce positioning errors,especially rotation errors.In order to ensure the accurate implementation of TBI and the safety of patients,it is necessary to use OSMS for auxiliary positioning and intra-fractional position monitoring.

Objective To investigate the clinical effect of distal clavicle anatomical locking plate internal fixation com-bined with coracoclavicular ligament reconstruction in the treatment of old Neer type Ⅱb distal clavicle fractures.Methods Ninety-five patients with old Neer type Ⅱb distal clavicle fractures admitted to the Department of Emergency Trauma Surgery,Nanyang First People's Hospital from February 2019 to January 2022 were selected as the research subjects,and the patients were divided into a control group(n=50)and an observation group(n=45)according to the surgical protocols.The patients in the control group received distal clavicle anatomical locking plate internal fixation,while the patients in the observation group received distal clavicle anatomical locking plate internal fixation combined with coracoclavicular ligament reconstruction.The fracture healing time of patients in the two groups was calculated based on the criteria of blurred fracture line under X-ray,continuity of bone scab passing through the fracture line,and the absence of pain on percussion and pressure;at the final follow-up,the functional recovery of the shoulder joint was evaluated according to Herscovici efficacy criteria to calculate the overall excellent rate;before operation,at 6 months after operation,and at 12 months after operation,the subjective pain of patients in the resting state was evaluated by using the visual analogue scale(VAS),the shoulder joint function of patients in the resting state was evaluated by using the Constant-Murley scale,and the coracoclavicular distance,acromioclavicular distance,forward flexion mobility,and external rotation mobility of patients were determined by using the spiral CT.The perioperative complications such as superficial incision infection,distal fracture displacement,shoulder joint pain,vascular nerve injury,re-fracture,and bone infection were compared between the two groups.Results The absorption time of absorbable sutures of patients in the observation group was(4.12±1.28)weeks.The fracture healing time of patients in the observation group was significantly shorter than that in the control group(t=5.558,P＜0.05).The overall excellent rate of shoulder joint function recovery of patients in the observation group was significantly higher than that in the control group(x2=4.222,P＜0.05).Before operation,there was no statistically significant difference in the VAS score and Constant-Murley score of patients between the control group and the observation group(P＞0.05);at 6 and 12 months after operation,the VAS scores of the patients in the two groups were significantly lower than those before operation,while the Constant-Murley scores were signifi-cantly higher than those before operation(P＜0.05);the VAS scores of patients in the two groups at 12 months after operation were significantly lower than those at 6 months after operation,while the Constant-Murley scores were significantly higher than those at 6 months after operation(P＜0.05);at 6 and 12 months after operation,the VAS scores of patients in the observation group were significantly lower than those in the control group,while the Constant-Murley scores were significantly higher than those in the control group(P＜0.05).Before operation,there was no statistically significant difference in coracoclavicular distance,acromioclavicular distance,forward flexion mobility,and external rotation mobility between the control group and the observation group(P＞0.05);at 6 and 12 months after operation,the coracoclavicular distance and acromioclavicular distance of patients in the two groups were significantly smaller than those before operation,while the forward flexion mobility and external rotation mobility were significantly greater than those before operation(P＜0.05);the coracoclavicular distance and acromio-clavicular distance of patients in the two groups at 12 months after operation were significantly smaller than those at 6 months after operation,while the forward flexion mobility and external rotation mobility were significantly greater than those at 6 months after operation(P＜0.05);at 6 and 12 months after operation,the coracoclavicular distance and acromioclavicular distance of patients in the observation group were significantly smaller than those in the control group,while the forward flexion mobility and external rotation mobility were significantly greater than those in the control group(P＜0.05).There were no perioperative complications in patients in the two groups,such as vascular nerve injury,re-fracture,and bone infection.The total complication rates of patients in the control group and the observation group were 6.00％(3/50)and 6.67％(3/45),respectively;there was no statistically significant difference in total complication rates of patients between the control group and the observation group(x2=0.084,P＞0.05).Conclusion Distal clavicle anatomical locking plate internal fixation combined with coracocla-vicular ligament reconstruction has a significant effect in the treatment of old Neer type Ⅱb distal clavicle fractures,which can quicken fracture healing,reduce pain,and improve shoulder joint function and the three-dimensional morphology of the acromiocla-vicular joint,with few complications.