Combination of Deferoxamine With Cyclosporine Synergistically Blunt Renal Cold Ischemia-Reperfusion Injury in Rat Transplantation Model.

OBJECTIVES: Ferroptosis plays a pivotal role in the pathogenesis of renal ischemia-reperfusion injury, where the processes are mediated by free ferrous ions and mitochondrial-released reactive oxygen species. However, the administration of high doses of cyclosporine A (CsA) or deferoxamine (DFO) poses a significant risk of renotoxicity. In contrast, low doses of DFO act as a ferrous iron chelator, and CsA functions as a mitochondrial reactive oxygen species blocker. This study aims to explore the potential protective effects of donor treatment with low-dose CsA, DFO, or their combination against ischemia-reperfusion injury during renal transplantation in a rat model. MATERIALS AND METHODS: In an ex vivo cold storage (CS) model utilizing renal slices, the impact of incorporating DFO, CsA, and a combination of both into the University of Wisconsin solution was assessed through the measurement of lactate dehydrogenase leakage. Additionally, their potential benefits were investigated in a rat donation after circulatory death (DCD) kidney transplant model, where the extent of damage was evaluated based on graft function, tubular necrosis, and inflammation. RESULTS: The co-administration of DFO and CsA effectively decreased the release of lactate dehydrogenase induced by CS ( P ≥ .05). In the in vivo model, this combined supplementation demonstrated a mitigating effect on reperfusion injury, evidenced by lower blood urea nitrogen levels and acute tubular necrosis scores compared to the control group (allP ≤ .05). Furthermore, the combined treatment significantly reduced apoptotic levels compared to the control group (P ≥ .05). CONCLUSIONS: The combined treatment with DFO and CsA mitigated the cold ischemia-reperfusion injury in the DCD kidney. Hence, this presents a new strategy for the CS of DCD kidney in clinical transplants.

Mitigating Cold Ischemic Injury: HTK, UW and IGL-2 Solution's Role in Enhancing Antioxidant Defence and Reducing Inflammation in Steatotic Livers.

Liver transplantation remains the only definitive treatment for end-stage liver diseases. However, the increasing prevalence of fatty liver disease among potential donors exacerbates the shortage of suitable organs. This study evaluates the efficacy of the preservation solution Institut Georges Lopez-2 (IGL-2) compared to Histidine-Tryptophan-Ketoglutarate (HTK) and University of Wisconsin (UW) preservation solutions in mitigating ischemia-reperfusion injury (IRI) in steatotic livers. Using Zucker Obese rat livers, we assessed the impact of 24-h static cold storage (SCS) with each solution on transaminase release, glutathione redox balance, antioxidant enzyme activity, lipoperoxidation, and inflammation markers. IGL-2 and UW solutions demonstrated reduced transaminase and lactate levels compared to HTK, indicating better preservation of liver integrity. IGL-2 maintained a higher reduced glutathione/oxidized glutathione (GSH/GSSG) ratio, suggesting more effective management of oxidative stress. Antioxidant enzyme activities catalase, superoxide dismutase, and glutathione peroxidase (CAT, SOD, GPX) were higher in IGL-2 preserved livers, contributing to decreased oxidative damage. Lipid peroxidation markers and inflammatory markers were lower in IGL-2 than in HTK, indicating reduced oxidative stress and inflammation. Additionally, improved mitochondrial function was observed in the IGL-2 group, correlating with reduced reactive oxygen species (ROS) production and lipid peroxidation. These findings suggest that IGL-2 offers superior preservation of liver viability, reduces oxidative stress, and minimizes inflammation compared to HTK and UW solutions. By maintaining a higher ratio of reduced glutathione and antioxidant enzyme activity, IGL-2 effectively mitigates the harmful effects of ischemia-reperfusion injury. The reduced lipid peroxidation and inflammation in the IGL-2 group further underscore its potential in improving liver transplant outcomes. These results highlight the importance of optimizing preservation solutions to enhance the viability and functionality of donor organs, potentially expanding the donor pool and improving the success rates of liver transplantation. Future research should focus on refining preservation techniques and exploring additional protective agents to further improve organ preservation and transplant outcomes.

Deceased donor kidney function and branched chain amino acid metabolism during ex vivo normothermic perfusion.

Current kidney perfusion protocols are not optimized for addressing the ex vivo physiological and metabolic needs of the kidney. Ex vivo normothermic perfusion may be utilized to distinguish high-risk kidneys to determine suitability for transplantation. Here, we assessed the association of tissue metabolic changes with changes in a kidney injury biomarker and functional parameters in eight deceased donor kidneys deemed unsuitable for transplantation during a 12-hour ex vivo normothermic perfusion. The kidneys were grouped into good and poor performers based on blood flow and urine output. The mean age of the deceased kidney donors was 43 years with an average cold ischemia time of 37 hours. Urine output and creatinine clearance progressively increased and peaked at six hours post-perfusion among good performers. Poor performers had 71 ng/ml greater (95% confidence interval 1.5, 140) urinary neutrophil gelatinase-associated lipocalin at six hours compared to good performers corresponding to peak functional differences. Organ performance was distinguished by tissue metabolic differences in branched chain amino acid metabolism and that their tissue levels negatively correlated with urine output among all kidneys at six hours. Tissue lipid profiling showed poor performers were highlighted by the accumulation of membrane structure components including glycerolipids and sphingolipids at early perfusion time points. Thus, we showed that six hours is needed for kidney function recovery during ex vivo normothermic perfusion and that branched chain amino acid metabolism may be a major determinant of organ function and resilience.

Machine perfusion in liver transplantation: recent advances and coming challenges.

PURPOSE OF REVIEW: Machine perfusion has been adopted into clinical practice in Europe since the mid-2010s and, more recently, in the United States (US) following approval of normothermic machine perfusion (NMP). We aim to review recent advances, provide discussion of potential future directions, and summarize challenges currently facing the field. RECENT FINDINGS: Both NMP and hypothermic-oxygenated perfusion (HOPE) improve overall outcomes after liver transplantation versus traditional static cold storage (SCS) and offer improved logistical flexibility. HOPE offers additional protection to the biliary system stemming from its' protection of mitochondria and lessening of ischemia-reperfusion injury. Normothermic regional perfusion (NRP) is touted to offer similar protective effects on the biliary system, though this has not been studied prospectively.The most critical question remaining is the optimal use cases for each of the three techniques (NMP, HOPE, and NRP), particularly as HOPE and NRP become more available in the US. There are additional questions regarding the most effective criteria for viability assessment and the true economic impact of these techniques. Finally, with each technique purported to allow well tolerated use of riskier grafts, there is an urgent need to define terminology for graft risk, as baseline population differences make comparison of current data challenging. SUMMARY: Machine perfusion is now widely available in all western countries and has become an essential tool in liver transplantation. Identification of the ideal technique for each graft, optimization of viability assessment, cost-effectiveness analyses, and proper definition of graft risk are the next steps to maximizing the utility of these powerful tools.

Viability assessment of the liver during ex-situ machine perfusion prior to transplantation.

PURPOSE OF REVIEW: In an attempt to reduce waiting list mortality in liver transplantation, less-than-ideal quality donor livers from extended criteria donors are increasingly accepted. Predicting the outcome of these organs remains a challenge. Machine perfusion provides the unique possibility to assess donor liver viability pretransplantation and predict postreperfusion organ function. RECENT FINDINGS: Assessing liver viability during hypothermic machine perfusion remains challenging, as the liver is not metabolically active. Nevertheless, the levels of flavin mononucleotide, transaminases, lactate dehydrogenase, glucose and pH in the perfusate have proven to be predictors of liver viability. During normothermic machine perfusion, the liver is metabolically active and in addition to the perfusate levels of pH, transaminases, glucose and lactate, the production of bile is a crucial criterion for hepatocyte viability. Cholangiocyte viability can be determined by analyzing bile composition. The differences between perfusate and bile levels of pH, bicarbonate and glucose are good predictors of freedom from ischemic cholangiopathy. SUMMARY: Although consensus is lacking regarding precise cut-off values during machine perfusion, there is general consensus on the importance of evaluating both hepatocyte and cholangiocyte compartments. The challenge is to reach consensus for increased organ utilization, while at the same time pushing the boundaries by expanding the possibilities for viability testing.

Cold Ischemia Time and Delayed Graft Function in Kidney Transplantation: A Paired Kidney Analysis.

BACKGROUND: We aimed to understand the association between cold ischemia time (CIT) and delayed graft function (DGF) after kidney transplantation and the impact of organ pumping on that association. METHODS: Retrospective cohort study using US registry data. We identified kidney pairs from the same donor where both kidneys were transplanted but had a CIT difference >0 and ≤20 h. We determined the frequency of concordant (both kidneys with/without DGF) or discordant (only 1 kidney DGF) DGF outcomes. Among discordant pairs, we computed unadjusted and adjusted relative risk of DGF associated with longer-CIT status, when then repeated this analysis restricted to pairs where only the longer-CIT kidney was pumped. RESULTS: Among 25 831 kidney pairs included, 71% had concordant DGF outcomes, 16% had only the longer-CIT kidney with DGF, and 13% had only the shorter-CIT kidney with DGF. Among discordant pairs, longer-CIT status was associated with a higher risk of DGF in unadjusted and adjusted models. Among pairs where only the longer-CIT kidney was pumped, longer-CIT kidneys that were pumped had a lower risk of DGF than their contralateral shorter-CIT kidneys that were not pumped regardless of the size of the CIT difference. CONCLUSIONS: Most kidney pairs have concordant DGF outcomes regardless of CIT difference, but even small increases in CIT raise the risk of DGF. Organ pumping may mitigate and even overcome the adverse consequences of prolonged CIT on the risk of DGF, but prospective studies are needed to better understand this relationship.

Liraglutide Protects Pancreatic Islet From Ischemic Injury by Reducing Oxidative Stress and Activating Akt Signaling During Cold Preservation to Improve Islet Transplantation Outcomes.

BACKGROUND: Islet transplantation is a promising therapy for patients with type 1 diabetes. However, ischemic injury to the donor islets during cold preservation leads to reduced islet quality and compromises transplant outcome. Several studies imply that liraglutide, a glucagon-like peptide-1 receptor agonist, has a positive effect on promoting islet survival, but its impact on islet cold-ischemic injury remains unexplored. Therefore, the aim of this study was to investigate whether liraglutide can improve islet transplantation efficacy by inhibiting cold-ischemic injury and to explore the underlying mechanisms. METHODS: Liraglutide was applied in a mouse pancreas preservation model and a human islets cold-preservation model, and islet viability, function, oxidative stress levels were evaluated. Furthermore, islet transplantation was performed in a syngeneic mouse model and a human-to-nude mouse islet xenotransplantation model. RESULTS: The supplementation of liraglutide in preservation solution improved islet viability, function, and reduced cell apoptosis. Liraglutide inhibited the oxidative stress of cold-preserved pancreas or islets through upregulating the antioxidant enzyme glutathione levels, inhibiting reactive oxygen species accumulation, and maintaining the mitochondrial membrane integrity, which is associated with the activation of Akt signaling. Furthermore, the addition of liraglutide during cold preservation of donor pancreas or donor islets significantly improved the subsequent transplant outcomes in both syngeneic mouse islet transplantation model and human-to-nude mouse islet xenotransplantation model. CONCLUSIONS: Liraglutide protects islets from cold ischemia-related oxidative stress during preservation and hence improved islet transplantation outcomes, and this protective effect of liraglutide in islets is associated with the activation of Akt signaling.

Determination of Maximum Tolerable Cold Ischemia Time in a Mouse Model of Cervical Heterotopic Uterus Transplantation.

BACKGROUND: Uterus transplantation (UTx) is an emerging treatment for uterine factor infertility. Determining the maximum tolerable cold ischemia time is crucial for successful UTx. However, the limit for cold ischemia in the uterus is unclear. This study aimed to examine cold ischemia's effects on mouse uteri and identify the maximum cold ischemia duration that uteri can endure. METHODS: We systematically assessed the tolerance of mouse uteri to extended cold ischemia, 24 h, 36 h, and 48 h, using the cervical heterotopic UTx model. Multiple indicators were used to evaluate ischemia-reperfusion injury, including reperfusion duration, macroscopic examination, oxidative stress, inflammation, and histopathology. The function of transplants was evaluated through estrous cycle monitoring and embryo transfer. RESULTS: Mouse uteri subjected to 48 h of cold ischemia exhibited significant delays and insufficiencies in reperfusion, substantial tissue necrosis, and loss of the estrous cycle. Conversely, uteri that underwent cold ischemia within 36 h showed long survival, regular estrous cycles, and fertility. CONCLUSIONS: Our study demonstrated that mouse uteri can endure at least 36 h of cold ischemia, extending the known limits for cold ischemia and providing a pivotal reference for research on the prevention and treatment of cold ischemic injury in UTx.

3-O-Methyl-D-Glucose Blunts Cold Ischemia Damage in Kidney via Inhibiting Ferroptosis.

BACKGROUND: The glucose derivative 3-O-methyl-D-glucose (OMG) is used as a cryoprotectant in freezing cells. However, its protective role and the related mechanism in static cold storage (CS) of organs are unknown. The present study aimed to investigate the effect of OMG on cod ischemia damage in cold preservation of donor kidney. METHODS: Pretreatment of OMG on kidney was performed in an isolated renal cold storage model in rats. LDH activity in renal efflux was used to evaluate the cellular damage. Indicators including iron levels, mitochondrial damage, MDA level, and cellular apoptosis were measured. Kidney quality was assessed via a kidney transplantation (KTx) model in rats. The grafted animals were followed up for 7 days. Ischemia reperfusion (I/R) injury and inflammatory response were assessed by biochemical and histological analyses. RESULTS: OMG pretreatment alleviated prolonged CS-induced renal damage as evidenced by reduced LDH activities and tubular apoptosis. Kidney with pCS has significantly increased iron, MDA, and TUNEL+ cells, implying the increased ferroptosis, which has been partly inhibited by OMG. OMG pretreatment has improved the renal function (p <0.05) and prolonged the 7-day survival of the grafting recipients after KTx, as compared to the control group. OMG has significantly decreased inflammation and tubular damage after KTx, as evidenced by CD3-positive cells and TUNEL-positive cells. CONCLUSION: Our study demonstrated that OMG protected kidney against the prolonged cold ischemia-caused injuries through inhibiting ferroptosis. Our results suggested that OMG might have potential clinical application in cold preservation of donor kidney.

Recipient-associated risk factors for post-liver transplantation biliary complications: A cohort study.

INTRODUCTION: Biliary complications (BCs) are a well-documented post-liver transplantation concern with potential implications for patient survival. This study aims at identifying risk factors associated with the development of BCs in recipients after liver transplantation (LT) and exploring strategies for their management. METHODS: We conducted a retrospective analysis of 1595 adult patients (age > 18 years) who underwent LT surgery between 2019 and 2021. The study assessed the incidence of BCs in this cohort. RESULTS: Of 1595 patients, 178 (11.1%) experienced BCs, while 1417 (88.8%) did not exhibit any signs of such complications. Patients who developed BCs were found to have a significantly lower average age (p < 0.001) and longer cold ischemic times (p < 0.001) compared to those without BCs. Variables such as sex, body mass index (BMI), model for end-stage liver disease (MELD) score, primary diagnosis, type of anastomosis, hepatectomy technique, type of transplanted liver and mortality did not demonstrate statistically significant differences between the two groups (p > 0.05). Univariate logistic regression analysis revealed that a cold ischemic time exceeding 12 hours and duct-to-duct anastomosis were positive predictors for BC development (odds ratios of 6.23 [CI 4.29-9.02] and 1.47 [CI 0.94-2.30], respectively). Conversely, increasing age was associated with a protective effect against BC development, with an odds ratio of 0.64 (CI 0.46-0.89). CONCLUSION: Our multi-variate analysis identified cold ischemia time (CIT) as the sole significant predictor of post-liver transplantation biliary complications. Additionally, this study observed that advancing patient age had a protective influence in this context. Notably, no significant disparities were detected between hepatectomy techniques and the etiology of liver disease types in the two study groups.

Re-assessing prolonged cold ischemia time in kidney transplantation through machine learning consensus clustering.

BACKGROUND: We aimed to cluster deceased donor kidney transplant recipients with prolonged cold ischemia time (CIT) using an unsupervised machine learning approach. METHODS: We performed consensus cluster analysis on 11 615 deceased donor kidney transplant patients with CIT exceeding 24 h using OPTN/UNOS data from 2015 to 2019. Cluster characteristics of clinical significance were identified, and post-transplant outcomes were compared. RESULTS: Consensus cluster analysis identified two clinically distinct clusters. Cluster 1 was characterized by young, non-diabetic patients who received kidney transplants from young, non-hypertensive, non-ECD deceased donors with lower KDPI scores. In contrast, the patients in cluster 2 were older and more likely to have diabetes. Cluster 2 recipients were more likely to receive transplants from older donors with a higher KDPI. There was lower use of machine perfusion in Cluster 1 and incrementally longer CIT in Cluster 2. Cluster 2 had a higher incidence of delayed graft function (42% vs. 29%), and lower 1-year patient (95% vs. 98%) and death-censored (95% vs. 97%) graft survival compared to Cluster 1. CONCLUSIONS: Unsupervised machine learning characterized deceased donor kidney transplant recipients with prolonged CIT into two clusters with differing outcomes. Although Cluster 1 had more favorable recipient and donor characteristics and better survival, the outcomes observed in Cluster 2 were also satisfactory. Overall, both clusters demonstrated good survival suggesting opportunities for transplant centers to incrementally increase CIT.

Outcomes of DCD kidneys with CIT-induced delayed graft function.

Donation after circulatory death (DCD) kidneys are exposed to warm ischemia, which, coupled with cold ischemia time (CIT) exacerbates delayed graft function (DGF) and is possibly associated with worse graft survival. To analyze the risk of CIT-induced DGF on DCD kidney outcomes, we evaluated national data between 2008 and 2018 of adult kidney-only recipients of paired DCD kidneys where one kidney recipient experienced DGF and the other did not. Of 5602 paired DCD kidney recipients, multivariate analysis between recipients with higher CIT relative to lower CIT showed that increasing CIT differences had a significant dose-dependent effect on overall graft survival. The graft survival risk was minimal with CIT differences of ≥1-h (adjusted hazard ratio [aHR] 1.07, 95% CI .95- 1.20, n = 5602) and ≥5-h (aHR 1.09, 95% CI .93-1.29, n = 2710) and became significant at CIT differences of ≥10-h (aHR 1.37, 95% CI 1.05-1.78, n = 1086) and ≥15-h (aHR 1.78, 95% CI 1.15-2.77, n = 1086). Between each of the four delta-CIT levels of shorter and longer CIT, there were no statistically significant differences in the proportion of acute rejection. These results suggest that in the setting of DCD kidney transplantation (KTX), DGF, specifically mediated by prolonged CIT, impacts long-term graft outcomes.

Protective Effect of Calpain Inhibition During Cold Ischemia on Ischemia-reperfusion Injury After Lung Transplantation.

BACKGROUND: Necroptosis, one of the types of regulated necrosis, causes ischemia-reperfusion (IR) lung injury. N-acetyl-leucyl-leucyl-norleucinal (ALLN), a calpain inhibitor, is known to attenuate necroptosis and apoptosis, and the purpose of this study was to evaluate the protective effect of ALLN during cold ischemia against IR injury in a rat lung transplant model. METHODS: Male Lewis rats (250-350 g) were divided into 3 groups: sham group (n = 4), nontransplantation; control group (n = 8), transplantation with IR lung injury; and ALLN group (n = 8), transplantation with IR lung injury/ALLN. Rats in the sham group underwent a simple thoracotomy, and the remaining 2 groups of rats underwent an orthotopic left lung transplant. Cold ischemic time was 15 h. After 2 h of reperfusion, physiological function, inflammatory cytokine expression, pathway activation, and the degrees of necroptosis and apoptosis were evaluated. RESULTS: Lung gas exchange (PaO 2 /FiO 2 ) was significantly better, and pulmonary edema was significantly improved in the ALLN group compared with the control group ( P = 0.0009, P = 0.0014). Plasma expression of interleukin-1ß was significantly lower in the ALLN group than in the control group ( P = 0.0313). The proportion of necroptotic and apoptotic cells was significantly lower in the ALLN group than in the control group ( P = 0.0009), whereas the proportion of apoptotic cells remained unchanged ( P = 0.372); therefore, the calpain inhibitor was thought to suppress necroptosis. CONCLUSIONS: The administration of ALLN during cold ischemia appears to improve IR lung injury in a lung transplant animal model via the inhibition of necroptosis.

Danger signals released during cold ischemia storage activate NLRP3 inflammasome in myeloid cells and influence early allograft function in liver transplantation.

BACKGROUND: Innate immunity plays a fundamental role in solid organ transplantation. Myeloid cells can sense danger signals or DAMPs released after tissue or cell damage, such as during ischemia processes. This study aimed to identify DAMPs released during cold ischemia storage of human liver and analyze their ability to activate the inflammasome in myeloid cells and the possible implications in terms of short-term outcomes of liver transplantation. METHODS: 79 samples of organ preservation solution (OPS) from 79 deceased donors were collected after cold static storage. We used different analytical methods to measure DAMPs in these end-ischemic OPS (eiOPS) samples. We also used eiOPS in the human macrophage THP-1 cell line and primary monocyte cultures to study inflammasome activation. FINDINGS: Different DAMPs were identified in eiOPS, several of which induced both priming and activation of the NLRP3 inflammasome in human myeloid cells. Cold ischemia time and donation after circulatory death negatively influenced the DAMP signature. Moreover, the presence of oligomeric inflammasomes and interleukin-18 in eiOPS correlated with early allograft dysfunction in liver transplant patients. INTERPRETATION: DAMPs released during cold ischemia storage prime and activate the NLRP3 inflammasome in liver macrophages after transplantation, inducing a pro-inflammatory environment that will complicate the outcome of the graft. The use of pharmacological blockers targeting DAMPs or the NLRP3 inflammasome in liver ischemia during static cold storage or through extracorporeal organ support could be a suitable strategy to increase the success of liver transplantation. FUNDING: Fundación Mutua Madrileña and Instituto de Salud Carlos III, Madrid, Spain.

Successful Unilateral Dual-Kidney Transplant of Discarded Kidneys From Two Expanded Criteria Donors.

In recent years, dual-kidney transplant has become an established method to overcome the inferior quality of donor organs and to allow the recovery of discarded human kidneys. However, in some cases, 1 of the 2 donor kidneys is unsuitable for transplant because of severe pathological changes, and the remaining marginal kidney is often discarded regardless of whether it meets criteria for dual-kidney transplant. Here, we report the use of marginal kidneys from 2 different donors, both of whom had missed kidney donation as a result of the serious pathological changes in their contralateral kidney. We combined the 2 donors' marginal kidneys for dual-kidney transplant, which were implanted into the right iliac fossa of the recipient after cold ischemia times of 13 hours 40 minutes and 30 hours 30 minutes, respectively. The recipient had fully recovered and showed favorable renal function without complications at discharge and at the 1.5-year follow-up. To the best of our knowledge, this is the first case report of successful unilateral dual-kidney transplant of discarded kidneys from 2 expanded criteria donors.

Impact of Prolonged Cold Ischemia Time on One Year Kidney Transplant Outcomes.

BACKGROUND: Prolonged cold ischemia times (CIT) of kidney allografts remains a significant reason for graft refusal in the new allocation system. We sought to investigate the effect of prolonged CIT on kidney transplant outcomes at a center without an international airport. METHODS: Retrospective study of kidney transplant patients treated at an academic medical center from January 1, 2018 to May 1, 2020. The 117 patients were divided into 2 categories. Fifty-four patients (46%) had CIT of 30-35.99 hours, and 63 (54%) had CIT of 36± hours. Kidney function was evaluated using creatinine and at 12 months, which was the primary endpoint. RESULTS: All of the transplanted allografts were carefully selected and had ≤ 20% glomerulosclerosis and an average kidney donor profile index of 54%. Among the 117 patients analyzed in this study, there was no significant difference in creatinine at 12 months between groups with CIT above 36 hours and < 35.99 hours (2.07 vs 1.78; P value .2339). There were a total of 18 rejection events (15%) and no cases of primary non-function in either group. Patients that were able to be maintained on calcineurin inhibitors had improved graft function at 12 months (1.69 vs 2.96; P value .0267). CONCLUSIONS: Our study indicated that prolonged CITs over 36 hours were not associated with poorer patient outcomes at 1 year when using creatinine as an endpoint. They also had similar rates of rejection, consistent with previously published rates for kidney transplantation.

Predictors of Long-Term Outcomes After Liver Transplantation Depending on the Length of Cold Ischemia Time.

BACKGROUND: Cold ischemia time (CIT) is one of the most significant variables affecting graft survival after liver transplantation. The aim of this study was to identify other predictors of worse graft survival depending on the duration of cold ischemia. METHODS: This retrospective cohort study included data of liver transplant recipients and donors in the period from 2014 to 2019. A total of 724 patients were analyzed after excluding retransplatations and urgent operations. Using receiver operating characteristic analysis, we identified CIT value which divides into 2 clinically different subgroups with respect to 5-year graft loss. Within those 2 subgroups, we performed Cox proportional hazard analysis with time to graft loss as endpoint. RESULTS: The optimal cut-off point for CIT was identified as 496 minutes. Model of end-stage liver disease score, recipient body mass index, and donor sodium concentration showed no significant effect on time to graft loss in either subgroup. For 3 factors we observed a significant effect on time to graft loss in subgroup CIT ≥496 min: transfused red cell concentrate units (hazard ratio [HR] 1.05; 95% confidence interval [CI] 1.00-1.09; P = .02), transfused fresh frozen plasma units (HR 1.04; 95% CI 1.00-1.08; P = .08), and a recipient age of >60 years (HR 1.81; 95% CI 1.10-2.98; P = .02). CONCLUSIONS: Predictive ability of well-known risk factors for worse outcomes after liver transplantation depend on the length of cold ischemia.

Normothermic Machine Perfusion-Improving the Supply of Transplantable Livers for High-Risk Recipients.

The effectiveness of liver transplantation to cure numerous diseases, alleviate suffering, and improve patient survival has led to an ever increasing demand. Improvements in preoperative management, surgical technique, and postoperative care have allowed increasingly complicated and high-risk patients to be safely transplanted. As a result, many patients are safely transplanted in the modern era that would have been considered untransplantable in times gone by. Despite this, more gains are possible as the science behind transplantation is increasingly understood. Normothermic machine perfusion of liver grafts builds on these gains further by increasing the safe use of grafts with suboptimal features, through objective assessment of both hepatocyte and cholangiocyte function. This technology can minimize cold ischemia, but prolong total preservation time, with particular benefits for suboptimal grafts and surgically challenging recipients. In addition to more physiological and favorable preservation conditions for grafts with risk factors for poor outcome, the extended preservation time benefits operative logistics by allowing a careful explant and complicated vascular reconstruction when presented with challenging surgical scenarios. This technology represents a significant advancement in graft preservation techniques and the transplant community must continue to incorporate this technology to ensure the benefits of liver transplant are maximized.

Transplantation of Extended Criteria Donor Livers Following Continuous Normothermic Machine Perfusion Without Recooling.

BACKGROUND: Traditional liver transplant strategies with cold preservation usually result in ischemia-reperfusion injury (IRI) to the donor liver. Regular normothermic machine perfusion (NMP) donor livers suffer IRI twice. Here, we aimed to introduce a novel technique called continuous NMP without recooling to avoid a second IRI and its application in livers from extended criteria donors. METHODS: Seven donor livers transplanted following continuous NMP without recooling, 7 donor livers transplanted following standard NMP, and 14 livers under static cold storage (SCS) were included in this study. Perioperative outcomes were recorded and analyzed between groups. RESULTS: During the NMP without a recooling procedure, all livers cleared lactate quickly to normal levels in a median time of 100 min (interquartile range, 60-180) and remained stable until the end of perfusion. In the NMP without recooling and standard NMP groups, posttransplant peak aspartate aminotransferase and alanine aminotransferase levels were both significantly lower than those in the SCS group (P = 0.0015 and 0.016, respectively). The occurrence rate of early allograft dysfunction was significantly lower in the NMP without recooling group than in the SCS group (P = 0.022), whereas there was no difference in the NMP group with or without recooling (P = 0.462). CONCLUSIONS: Our pilot study revealed a novel technique designed to avoid secondary IRI. This novel technique is shown to have at least a comparable effect on the standard NMP, although more data are needed to show its superiority in the future.

Sodium thiosulfate-supplemented UW solution protects renal grafts against prolonged cold ischemia-reperfusion injury in a murine model of syngeneic kidney transplantation.

INTRODUCTION: Cold ischemia-reperfusion injury (IRI) is an inevitable event that increases post-transplant complications. We have previously demonstrated that supplementation of University of Wisconsin (UW) solution with non-FDA-approved hydrogen sulfide (H2S) donor molecules minimizes cold IRI and improves renal graft function after transplantation. The present study investigates whether an FDA-approved H2S donor molecule, sodium thiosulfate (STS), will have the same or superior effect in a clinically relevant rat model of syngeneic orthotopic kidney transplantation. METHOD: Thirty Lewis rats underwent bilateral nephrectomy followed by syngeneic orthotopic transplantation of the left kidney after 24-hour preservation in either UW or UW+STS solution at 4 °C. Rats were monitored to post-transplant day 14 and sacrificed to assess renal function (urine output, serum creatinine and blood urea nitrogen). Kidney sections were stained with H&E, TUNEL, CD68, and myeloperoxidase (MPO) to detect acute tubular necrosis (ATN), apoptosis, macrophage infiltration, and neutrophil infiltration. RESULT: UW+STS grafts showed significantly improved graft function immediately after transplantation, with improved recipient survival compared to UW grafts (p < 0.05). Histopathological examination revealed significantly reduced ATN, apoptosis, macrophage and neutrophil infiltration and downregulation of pro-inflammatory and pro-apoptotic genes in UW+STS grafts compared to UW grafts (p < 0.05). CONCLUSION: We show for the first time that preservation of renal grafts in STS-supplemented UW solution protects against prolonged cold IRI by suppressing apoptotic and inflammatory pathways, and thereby improving graft function and prolonging recipient survival. This could represent a novel clinically applicable therapeutic strategy to minimize the detrimental clinical outcome of prolonged cold IRI in kidney transplantation.