A systematic review of kidney transplantation from expanded criteria donors

Frozen section evaluation of deceased donor kidney biopsies: A field guide

The demand for donated kidneys is steadily increasing, making it critical that the transplant community maximizes the use of organs procured from deceased donors. When a donated kidney becomes available, a transplant program evaluates the suitability of the organ for their patients and will choose whether to decline or accept. A pre-implantation biopsy may be performed if the transplant center is unsure about the suitability of the organ. More than half of deceased donor kidneys are biopsied prior to implantation, and "biopsy findings" is the most commonly cited reason for a kidney not being accepted for transplantation. This is despite the fact that retrospective analyses at multiple centers have revealed that the results of kidney pre-implantation biopsies are poorly reproducible, inaccurate, and do not correlate with clinical outcomes. A prospective study comparing the scores of paraffin-embedded pre-implantation biopsies given by on-call pathologists to scores given by experienced renal pathologists found that only the evaluation by the renal pathologist was significantly associated with graft function and survival. In 2023, the Organ Procurement and Transplantation Network implemented the Standardized Kidney Biopsy Reporting and Data Collection policy, specifying how kidney pre-implantation biopsies should be scored and reported. This article aims to increase awareness of the reporting criteria for kidney pre-implantation biopsies, thereby increasing the accuracy and reproducibility of the results and decreasing the number of deceased donor kidneys that are inappropriately discarded.

GLP-1 and glucagon receptor dual agonism ameliorates kidney allograft fibrosis by improving lipid metabolism

Introduction

Kidney allograft fibrosis accelerates the progression of chronic kidney disease (CKD), leads to allograft failure, and increases patient mortality. Emerging evidence suggests that metabolic syndrome in transplant recipients is associated with fibrosis development. However, it remains unclear whether targeting metabolic pathways can mitigate allograft fibrosis. This study aimed to explore the potential of targeting metabolic pathways using the GLP-1R/GCGR dual agonist TB001 for the treatment of kidney allograft fibrosis.

Methods

Kidney allograft fibrosis was induced in rat kidney transplant models. Histological analysis, transcriptome sequencing, and in vitro experiments were performed to investigate the efficacy of TB001 and its underlying mechanisms.

Results

Compared with the control group, TB001-treated recipients had significantly improved kidney allograft function, as evidenced by lower creatinine and 24-hour urine protein levels. Moreover, TB001 treatment decreased the body weight and serum total cholesterol, LDL-cholesterol, and TNF-α levels in transplant recipients, indicating metabolic improvements. Pathological analysis demonstrated that TB001 treatment reduced inflammatory cell infiltration and downregulated the expression of fibrosis markers, including TGF-β1, α-SMA, COL1A1, and Vimentin. Further transcriptome sequencing of kidney grafts revealed that TB001-treated group had a gene expression pattern similar to that of the syngeneic control group and showed significant enhancement of lipid metabolism-related pathways, particularly the PPAR pathway. In vivo and in vitro experiments further demonstrated that TB001 upregulated the expression of CPT1A, a key molecule involved in lipid metabolism, and inhibited TGF-β1/Smad2/3/Twist and PKC-α/PKC-β pathways.

Conclusion

Targeting metabolic pathways using the GLP-1R/GCGR dual agonist TB001 shows potential for managing kidney allograft fibrosis.

Kidney Donor Risk Index and Cardiovascular Complications in a Long-Term Follow-Up Observation

Background: The suitability of the Kidney Donor Risk Index (KDRI) has not been fully validated in the European population. The aim of this study was to evaluate the value of the KDRI in predicting kidney graft function and cardiovascular events (CVEs) in a Polish cohort of kidney transplant recipients (KTRs). Methods: In this retrospective study kidney graft function and CVEs were analyzed among 1420 patients transplanted between 1999 and 2017 and followed until 2021. The KDRI was calculated according to the formula proposed by Rao. Patients were assigned into quartiles (Qs) of KDRI values. Results: Patients in Q4 were older, with higher BMI, longer cold ischemia time (CIT), and a greater rate of ischemic heart disease at the transplantation. The KDRI value determined both early and long-term graft function. During a median follow-up period of 91 months, at least one cardiovascular event was noted in 227 (16.0%) kidney transplant recipients. There was a significant increasing trend for the occurrence of post-transplant CV complications along the consecutive KDRI quartiles (χ2 = 7.3; p < 0.01) among kidney transplant patients younger than 50 years at the time of transplantation. Conclusions: The KDRI is an adequate prognostic tool also for the European population. Despite the KDRI not being used for allocation in Poland we found that kidneys with a higher KDRI are allocated to recipients with worse survival prognosis. The quality of kidneys from a deceased donor may be related to the occurrence of post-transplant cardiovascular complications in recipients younger than 50 years at the transplantation, including those without history of comorbidities such as diabetes or cardiovascular disease.

Multicentre, multi-arm, double-blind randomised placebo-controlled dose-finding trial investigating the safety and Efficacy of MirococePt (APT070) In Reducing delayed graft function In the Kidney ALlograft (EMPIRIKAL-2): study protocol for a randomised controlled trial

BACKGROUND

Up to 50% of kidney transplant patients are diagnosed with delayed graft function (DGF) following transplantation-the majority being linked to ischaemia reperfusion injury (IRI). DGF is traditionally defined as the requirement for dialysis during the first week after transplantation and is associated with inferior graft and patient outcomes. Local synthesis of complement components, largely by the renal tubule, plays a critical role in IRI. We have developed Mirococept, a membrane-targeted complement inhibitor, that can be administered to the donor kidney ex vivo prior to transplantation. After administration, Mirococept is retained in the donor organ, thereby minimising the risk of systemic side effects. We previously launched the EMPIRIKAL study aiming to evaluate the efficacy of Mirococept in reducing DGF in deceased-donor kidney transplantation (KT). The funding body recommended termination of the study to allow a dose-saturating study before the next stage of clinical evaluation. This was carried out in a porcine kidney model and led to a revised dosing regimen for EMPIRIKAL-2 (60-180 mg compared with 5-25 mg in the initial trial). The EMPIRIKAL-2 trial (REC 24/NE/0071) aims to identify the most safe and efficacious dose of Mirococept to reduce DGF rate in deceased-donor KT.

METHODS AND ANALYSIS

EMPIRIKAL-2 is a Phase IIa multicentre double-blind randomised controlled trial (RCT) with an initial safety run. Participants will be recruited from renal departments at National Health Service tertiary hospital sites in the UK. The purpose of the safety run is to assess the tolerance of each of the three proposed Mirococept doses (60, 120 or 180 mg), before the RCT begins. Three patients will be assigned to each treatment dose, starting from the lower dose. The safety run will be considered successful if at least one dose can be taken forward to the RCT for comparison to placebo.If safety is met, 144 participants (36 per arm excluding drop-outs) will be randomised to all doses meeting the safety criteria or placebo on a 1:1:1:1 basis. The primary endpoint is DGF, defined as the requirement for dialysis during the first week after transplantation. Safety evaluation will include the monitoring of laboratory data and the recording of all adverse events. Immunosuppression therapy, antibiotic and antiviral prophylaxis will be administered as per local centre protocols. Enrolment in the RCT is anticipated to take approximately 12 months, and patients will be followed-up for 12 months.

ETHICS AND DISSEMINATION

The study has been approved by the Northeast - Newcastle and North Tyneside 2 Research Ethics Service Committee, REC reference 24/NE/0071. The results of the study will be reported and disseminated at international conferences and in peer-reviewed scientific journals. Once published, a lay summary of the results will be made available to participants who request this information.

TRIAL REGISTRATION NUMBER

ISRCTN14279222. Registered on 4 July 2024.

PROTOCOL VERSION

2.0 dated 9 May 2024.

Beyond the icebox: modern strategies in organ preservation for transplantation

Organ transplantation, a critical treatment for end-stage organ failure, has witnessed significant advancements due to the integration of improved surgical techniques, immunosuppressive therapies, and donor-recipient matching. This review explores the progress of organ preservation, focusing on the shift from static cold storage (SCS) to advanced machine perfusion techniques such as hypothermic (HMP) and normothermic machine perfusion (NMP). Although SCS has been the standard approach, its limitations in preserving marginal organs and preventing ischemia-reperfusion injury (IRI) have led to the adoption of HMP and NMP. HMP, which is now the gold standard for high-risk donor kidneys, reduces metabolic activity and improves posttransplant outcomes. NMP allows real-time organ viability assessment and reconditioning, especially for liver transplants. Controlled oxygenated rewarming further minimizes IRI by addressing mitochondrial dysfunction. The review also highlights the potential of cryopreservation for long-term organ storage, despite challenges with ice formation. These advances are crucial for expanding the donor pool, improving transplant success rates, and addressing organ shortages. Continued innovation is necessary to meet the growing demands of transplantation and save more lives.

Circulating Immune Complexes and Complement Activation in Sensitized Kidney Transplant Recipients

Chronic antibody-mediated rejection in kidney transplantation is a common cause of graft loss in the late post-transplant period. In this process, the role of the classical complement activation pathway is crucial due to the formation of immune complexes between donor-specific antibodies (DSAs) and donor antigens and the attachment of the C1q complement fragment. This study aimed to determine the levels of circulating C1q immunocomplexes (CIC-C1q) and complement activation (CH50), in sensitized kidney transplant recipients (KTRs). In this cross-sectional study we used serum samples from KTRs with de novo or preformed DSAs (n = 14), KTRs without DSAs (n = 28), and 22 subjects with no history of chronic kidney disease (controls). C1q immunocomplexes and CH50 concentration in serum were measured with the enzyme immunoassay (EIA) kit MicroVue CIC-C1q (Quidel, Athens, OH, USA) and EIA kit MicroVue CH50 (Quidel, OH, USA), respectively. Higher concentrations of CIC-C1q was observed in KTRs with DSAs in comparison with controls and with KTRs with no DSAs (6.8 ± 2.7 and 4.8 ± 1.9 vs. 5.0 ± 1.2 μg Eq/mL, respectively, p < 0.01). We found no difference in CIC-C1q between KTRs with no DSAs and controls. CIC-C1q levels were positively correlated with DSA titer. CH50 levels were decreased in KTRs with DSAs in comparison with controls and KTRs with no DSAs (39 ± 15 vs. 68 ± 40 and 71 ± 34 U Eq/mL, respectively, p < 0.01). There was no difference in CH50 between DSA-negative KTRs and controls. Kidney transplant recipients with DSAs had increased serum levels of C1q immunocomplexes and increased classical pathway complement activation.

Outcomes following concomitant multiorgan heart transplantation from circulatory death donors: The United States experience

BACKGROUND

Donation after circulatory death (DCD) has reemerged as a method of expanding the donor heart pool. Given the high waitlist mortality of multiorgan heart candidates, we evaluated waitlist outcomes associated with willingness to consider DCD offers and post-transplant outcomes following DCD transplant for these candidates.

METHODS

We identified adult multiorgan heart candidates and recipients between January 1, 2020 and March 31, 2023 nationally. Among candidates that met inclusion criteria, we compared the cumulative incidence of transplant, with waitlist death/deterioration as a competing risk, by willingness to consider DCD offers. Among recipients of DCD versus brain death (DBD) transplants, we compared perioperative outcomes and post-transplant survival.

RESULTS

Of 1,802 heart-kidney, 266 heart-liver, and 440 heart-lung candidates, 15.8%, 12.4%, and 31.1%, respectively, were willing to consider DCD offers. On adjusted analysis, willingness to consider DCD offers was associated with higher likelihood of transplant for all multiorgan heart candidates and decreased likelihood of waitlist deterioration for heart-lung candidates. Of 1,100 heart-kidney, 173 heart-liver, and 159 heart-lung recipients, 5.4%, 2.3%, and 2.5%, respectively, received DCD organs. Recipients of DCD and DBD heart-kidney transplants had a similar likelihood of perioperative outcomes and 1-year survival. All other DCD multiorgan heart recipients have survived to the last follow-up.

CONCLUSIONS

Multiorgan heart candidates who were willing to consider DCD offers had favorable waitlist outcomes, and heart-kidney recipients of DCD transplants had similar post-transplant outcomes to recipients of DBD transplants. We recommend the use of DCD organs to increase the donor pool for these high-risk candidates.

Normothermic and hypothermic machine perfusion preservation versus static cold storage for deceased donor kidney transplantation

BACKGROUND

Kidney transplantation is the optimal treatment for kidney failure. Donation, transport and transplant of kidney grafts leads to significant ischaemia reperfusion injury. Static cold storage (SCS), whereby the kidney is stored on ice after removal from the donor until the time of implantation, represents the simplest preservation method. However, technology is now available to perfuse or "pump" the kidney during the transport phase ("continuous") or at the recipient centre ("end-ischaemic"). This can be done at a variety of temperatures and using different perfusates. The effectiveness of these treatments manifests as improved kidney function post-transplant.

OBJECTIVES

To compare machine perfusion (MP) technologies (hypothermic machine perfusion (HMP) and (sub) normothermic machine perfusion (NMP)) with each other and with standard SCS.

SEARCH METHODS

We contacted the information specialist and searched the Cochrane Kidney and Transplant Register of Studies until 15 June 2024 using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs comparing machine perfusion techniques with each other or versus SCS for deceased donor kidney transplantation were eligible for inclusion. All donor types were included (donor after circulatory death (DCD) and brainstem death (DBD), standard and extended/expanded criteria donors). Both paired and unpaired studies were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

The results of the literature search were screened, and a standard data extraction form was used to collect data. Both of these steps were performed by two independent authors. Dichotomous outcome results were expressed as risk ratios (RR) with 95% confidence intervals (CI). Survival analyses (time-to-event) were performed with the generic inverse variance meta-analysis of hazard ratios (HR). Continuous scales of measurement were expressed as a mean difference (MD). Random effects models were used for data analysis. The primary outcome was the incidence of delayed graft function (DGF). Secondary outcomes included graft survival, incidence of primary non-function (PNF), DGF duration, economic implications, graft function, patient survival and incidence of acute rejection. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Twenty-two studies (4007 participants) were included. The risk of bias was generally low across all studies and bias domains. The majority of the evidence compared non-oxygenated HMP with standard SCS (19 studies). The use of non-oxygenated HMP reduces the rate of DGF compared to SCS (16 studies, 3078 participants: RR 0.78, 95% CI 0.69 to 0.88; P < 0.0001; I2 = 31%; high certainty evidence). Subgroup analysis revealed that continuous (from donor hospital to implanting centre) HMP reduces DGF (high certainty evidence). In contrast, this benefit over SCS was not seen when non-oxygenated HMP was not performed continuously (low certainty evidence). Non-oxygenated HMP reduces DGF in both DCD and DBD settings in studies performed in the 'modern era' and when cold ischaemia times (CIT) were short. The number of perfusions required to prevent one episode of DGF was 7.69 and 12.5 in DCD and DBD grafts, respectively. Continuous non-oxygenated HMP versus SCS also improves one-year graft survival (3 studies, 1056 participants: HR 0.46, 0.29 to 0.75; P = 0.002; I2 = 0%; high certainty evidence). Assessing graft survival at maximal follow-up confirmed a benefit of continuous non-oxygenated HMP over SCS (4 studies, 1124 participants (follow-up 1 to 10 years): HR 0.55, 95% CI 0.40 to 0.77; P = 0.0005; I2 = 0%; high certainty evidence). This effect was not seen in studies where HMP was not continuous. The effect of non-oxygenated HMP on our other outcomes (PNF, incidence of acute rejection, patient survival, hospital stay, long-term graft function, duration of DGF) remains uncertain. Studies performing economic analyses suggest that HMP is either cost-saving (USA and European settings) or cost-effective (Brazil). One study investigated continuous oxygenated HMP versus non-oxygenated HMP (low risk of bias in all domains); the simple addition of oxygen during continuous HMP leads to additional benefits over non-oxygenated HMP in DCD donors (> 50 years), including further improvements in graft survival, improved one-year kidney function, and reduced acute rejection. One large, high-quality study investigated end-ischaemic oxygenated HMP versus SCS and found end-ischaemic oxygenated HMP (median machine perfusion time 4.6 hours) demonstrated no benefit compared to SCS. The impact of longer periods of end-ischaemic HMP is unknown. One study investigated NMP versus SCS (low risk of bias in all domains). One hour of end ischaemic NMP did not improve DGF compared with SCS alone. An indirect comparison revealed that continuous non-oxygenated HMP (the most studied intervention) was associated with improved graft survival compared with end-ischaemic NMP (indirect HR 0.31, 95% CI 0.11 to 0.92; P = 0.03). No studies investigated normothermic regional perfusion (NRP) or included any donors undergoing NRP.

AUTHORS' CONCLUSIONS

Continuous non-oxygenated HMP is superior to SCS in deceased donor kidney transplantation, reducing DGF, improving graft survival and proving cost-effective. This is true for both DBD and DCD kidneys, both short and long CITs, and remains true in the modern era (studies performed after 2008). In DCD donors (> 50 years), the simple addition of oxygen to continuous HMP further improves graft survival, kidney function and acute rejection rate compared to non-oxygenated HMP. Timing of HMP is important, and benefits have not been demonstrated with short periods (median 4.6 hours) of end-ischaemic HMP. End-ischaemic NMP (one hour) does not confer meaningful benefits over SCS alone and is inferior to continuous HMP in an indirect comparison of graft survival. Further studies assessing NMP for viability assessment and therapeutic delivery are warranted and in progress.

Kidney transplants from elderly donors: what we have learned 20 years after the Crystal City consensus criteria meeting

Based on the current projection of the general population and the combined increase in end-stage kidney disease with age, the number of elderly donors and recipients is increasing, raising crucial questions about how to minimize the discard rate of organs from elderly donors and improve graft and patient outcomes. In 2002, extended criteria donors were the focus of a meeting in Crystal City (VA, USA), with a goal of maximizing the use of organs from deceased donors. Since then, extended criteria donors have progressively contributed to a large number of transplanted grafts worldwide, posing specific issues for allocation systems, recipient management, and therapeutic approaches. This review analyzes what we have learned in the last 20 years about extended criteria donor utilization, the promising innovations in immunosuppressive management, and the molecular pathways involved in the aging process, which constitute potential targets for novel therapies.

Long-Term Outcomes after Conversion to a Belatacept-Based Immunosuppression in Kidney Transplant Recipients

BACKGROUND

Conversion to a belatacept-based immunosuppression is currently used as a calcineurin inhibitor (CNI) avoidance strategy when the CNI-based standard-of-care immunosuppression is not tolerated after kidney transplantation. However, there is a lack of evidence on the long-term benefit and safety after conversion to belatacept.

METHODS

We prospectively enrolled 311 kidney transplant recipients from 2007 to 2020 from two referral centers, converted from CNI to belatacept after transplant according to a prespecified protocol. Patients were matched at the time of conversion to patients maintained with CNIs, using optimal matching. The primary end point was death-censored allograft survival at 7 years. The secondary end points were patient survival, eGFR, and safety outcomes, including serious viral infections, immune-related complications, antibody-mediated rejection, T-cell-mediated rejection, de novo anti-HLA donor-specific antibody, de novo diabetes, cardiovascular events, and oncologic complications.

RESULTS

A total of 243 patients converted to belatacept (belatacept group) were matched to 243 patients maintained on CNIs (CNI control group). All recipient, transplant, functional, histologic, and immunologic parameters were well balanced between the two groups with a standardized mean difference below 0.05. At 7 years post-conversion to belatacept, allograft survival was 78% compared with 63% in the CNI control group ( P < 0.001 for log-rank test). The safety outcomes showed a similar rate of patient death (28% in the belatacept group versus 36% in the CNI control group), active antibody-mediated rejection (6% versus 7%), T-cell-mediated rejection (4% versus 4%), major adverse cardiovascular events, and cancer occurrence (9% versus 11%). A significantly higher rate of de novo proteinuria was observed in the belatacept group as compared with the CNI control group (37% versus 21%, P < 0.001).

CONCLUSIONS

This real-world evidence study shows that conversion to belatacept post-transplant was associated with lower risk of graft failure and acceptable safety outcomes compared with patients maintained on CNIs.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Long-term Outcomes after Conversion to Belatacept, NCT04733131 .

Post-transplant lymphoproliferative disorders following kidney transplantation: A literature review with updates on risk factors, prognostic indices, screening strategies, treatment and analysis of donor type

Post-transplant lymphoproliferative disorders (PTLD) is a devastating complication of kidney transplantation with an insidious presentation and potential to disseminate aggressively. This review delineates the risk factors, prognostic indexes, screening, current management algorithm and promising treatment strategies for PTLD. Kidneys from both extended criteria donors (ECD) and living donors (LD) are being increasingly used to expand the donor pool. This review also delineates whether PTLD outcomes vary based on these donor sources. While Epstein-Barr virus (EBV) is a well-known risk factor for PTLD development, the use of T-cell depleting induction agents has been increasingly implicated in aggressive, monomorphic forms of PTLD. Research regarding maintenance therapy is sparse. The international prognostic index seems to be the most validate prognostic tool. Screening for PTLD is controversial, as annual PET-CT is most sensitive but costly, while targeted monitoring of EBV-seronegative patients was more economically feasible, is recommended by the American Society of Transplantation, but is limited to a subset of the population. Other screening strategies such as using Immunoglobulin/T-cell receptor require further validation. A risk-stratified approach is taken in the treatment of PTLD. The first step is the reduction of immunosuppressants, after which rituximab and chemotherapy may be introduced if unsuccessful. Some novel treatments have also shown potential benefit in studies: brentuximab vedotin, chimeric antigen receptor T-cell therapy and EBV-specific cytotoxic T lymphocytes. Analysis of LD v DD recipients show no significant difference in incidence and mortality of PTLD but did reveal a shortened time to development of PTLD from transplant. Analysis of SCD vs ECD recipients show a higher incidence of PTLD in the ECD group, which might be attributed to longer time on dialysis for these patients, age, and the pro-inflammatory nature of these organs. However, incidence of PTLD overall is still extremely low. Efforts should be focused on optimising recipients instead. Minimising the use of T-cell depleting therapy while encouraging research on the effect of new immunosuppressants on PTLD, screening for EBV status are essential, while enabling shared decision-making during counselling when choosing kidney donor types and individualised risk tailoring are strongly advocated.

Overcoming the longest cold ischemia time yet seen in Korea using hypothermic machine perfusion in deceased donor kidney transplantation: a case report

To address a donor kidney shortage, marginal grafts have been applied in deceased donor kidney transplantation (DDKT). These grafts exhibit comparatively unfavorable outcomes, particularly when cold ischemia time (CIT) is prolonged. Hypothermic machine perfusion (HMP) has been investigated to mitigate the effects of prolonged CIT during graft transport. The present case involved successful management of the longest CIT recorded in Korea by employing HMP in DDKT. The donor was a 54-year-old man (Korean Kidney Donor Profile Index, 82%) with diabetes. The recipient, a 51-year-old man on peritoneal dialysis, had end-stage renal disease secondary to diabetic nephropathy. Following procurement, the left kidney was preserved using HMP. Inclement weather delayed graft transportation; consequently, the total CIT was 28 hours and 6 minutes, with the kidney preserved by HMP for 22 hours and 35 minutes. Postoperative graft function gradually recovered, and urine output was satisfactory. Delayed graft function was not observed, and the patient was discharged on postoperative day 13 without significant complications. Five months after surgery, his serum creatinine level was 1.7 mg/dL. Successful DDKT with a marginal donor graft via HMP, despite the longest CIT yet observed in Korea, underscores the usefulness of HMP in enhancing graft quality and preserving function.

Results in Kidney Transplant Recipients from Living Donors 75 Years of Age or Older

The increasing age of patients receiving renal replacement therapy (RRT) in Turkey, coupled with a shortage of kidney donors, has led to longer waiting times for transplants and an escalation in mortality rates. This retrospective study aimed to assess the effect on transplant outcomes of accepting kidneys from donors ≥70 years of age, given the rising number of older patients in the population. In all, 1400 patients were transplanted with kidneys from donors >50 years, with patient and graft survival as primary endpoints. Our results demonstrated that the most significant risk factors for graft function were recipient age >65 years, male sex, and presence of type 2 diabetes. Moreover, kidneys from donors ≥75 years of age achieved a half-life of 5 years. These findings suggest that donor age does not necessarily correlate with graft failure and that transplantation from older donors could help alleviate the organ shortage. Further research is needed to substantiate these conclusions.

Graft survival and delayed graft function with normothermic regional perfusion and rapid recovery after circulatory death in kidney transplantation: a propensity score matching study

BACKGROUND

A shortage of kidney grafts has led to the implementation of various strategies, including donations after circulatory death. The in situ normothermic regional perfusion technique has been introduced to improve graft quality by reducing warm ischemia times. However, there is limited evidence available on its mid- and long-term outcomes. Therefore, this study aimed to compare the incidence of delayed graft function, graft function, and survival at three years among three groups: brain death donors, rapid recovery, and normothermic regional perfusion.

METHODS

A retrospective analysis of a cohort of kidney transplantations was conducted at a single referral center between January 1, 2015, and December 31, 2019. Univariate and multivariate regression models and propensity score matching analysis were performed to compare recipient-related, transplantation procedure-related, donor-related, and kidney function variables.

RESULTS

A total of 327 patients were included, with 256 kidneys from brain death donors, 52 kidneys from rapid recovery, and 19 patients from normothermic regional perfusion. After propensity score matching, univariate and multivariate analyses showed a higher incidence of delayed graft function in the rapid recovery group compared to the others (OR: 2.39 CI95%: 1.19, 4.77) with a longer hospital stay (median 11, 15 and 10 days, respectively). However, no differences in 1- and 3-year graft function and survival were found.

CONCLUSIONS

Normothermic regional perfusion offers advantages over rapid recovery, with a reduced incidence of delayed graft function and a shorter hospital stay. However, no differences in mid-term graft function and survival were found.

Combining Oxygenated Cold Perfusion With Normothermic Ex Vivo Perfusion Improves the Outcome of Donation After Circulatory Death Porcine Kidney Transplantation

BACKGROUND

Ex vivo machine perfusion is a novel preservation technique for storing and assessing marginal kidney grafts. All ex vivo perfusion techniques have advantages and shortcomings. The current study analyzed whether a combination of oxygenated hypothermic machine perfusion (oxHMP) followed by a short period of normothermic ex vivo kidney perfusion (NEVKP) could combine the advantages of both techniques.

METHODS

Porcine kidneys were exposed to 30 min of warm ischemia followed by perfusion. Kidneys underwent either 16-h NEVKP or 16-h oxHMP. The third group was exposed to 16-h oxHMP followed by 3-h NEVKP (oxHMP + NEVKP group). After contralateral nephrectomy, grafts were autotransplanted and animals were followed up for 8 d.

RESULTS

All animals survived the follow-up period. Grafts preserved by continuous NEVKP showed improved function with lower peak serum creatinine and more rapid recovery compared with the other 2 groups. Urine neutrophil gelatinase-associated lipocalin, a marker of kidney injury, was found to be significantly lowered on postoperative day 3 in the oxHMP + NEVKP group compared with the other 2 groups.

CONCLUSIONS

A short period of NEVKP after oxHMP provides comparable short-term outcomes to prolonged NEVKP and is superior to oxHMP alone. A combination of oxHMP with end-ischemic NEVKP could be an attractive, practical strategy to combine the advantages of both preservation techniques.

Association between blood transfusion after kidney transplantation and risk for the development of de novo HLA donor-specific antibodies and poor clinical outcomes: A single-center retrospective study

BACKGROUND

Blood transfusion after kidney transplantation may increase the risk of sensitization and development of de novo human leukocyte antigen (HLA) donor-specific antibodies (DSAs). This study aimed to evaluate whether blood transfusion during the first year after kidney transplantation influences the development of de novo DSAs and clinical outcomes of kidney transplantation recipients.

METHODS

This retrospective cohort study included nonsensitized first-time kidney transplantation recipients at Tianjin First Central Hospital from 2010 to 2022. The incidence of de novo DSA development and clinical outcomes between the groups were compared. Luminex single antigen beads were used to monitor DSAs.

RESULTS

Of the 538 non-HLA-sensitized kidney transplantation recipients included in the study, 164 patients who received at least one unit of leukoreduced red blood cell transfusion within the first year (the transfused group), whereas the remaining 374 patients received no blood transfusion (the non-transfused group). Our analysis showed that there was a significant difference in the development of de novo DSAs and de novo anti-class I HLA-Ab between the two groups. Indeed, the transfused recipients had a higher serum creatinine and lower estimated glomerular filtration rate (eGFR) at 1-, 6-, and 12-month (all p > 0.05) after transplantation. Futhermore, a higher incidence of CMV infection, antibody-mediated rejection (AMR), hyper acute rejection (HAR), and delayed graft function (DGF) was identified in the transfused group (all p < 0.05). The graft survival was lower in the transfused group compared with patients in the non-transfused group (P = 0.002). Blood transfusion post-transplantation was a risk factor for de novo DSAs development but not an independent predictive factor for AMR and graft loss (odds ratio = 2.064 [1.243-3.429], p = 0.005).

CONCLUSIONS

Our study showed that blood transfusion after transplantation is associated with the occurrence of de novo DSAs increasing an immunological risk for poor clinical outcomes for kidney transplantation recipients.

All Expanded Criteria Donor Kidneys are Equal But are Some More Equal Than Others? A Population-Cohort Analysis of UK Transplant Registry Data

Survival outcomes for kidney transplant candidates based on expanded criteria donor (ECD) kidney type is unknown. A retrospective cohort study was undertaken of prospectively collected registry data of all waitlisted kidney failure patients receiving dialysis in the United Kingdom. All patients listed for their first kidney-alone transplant between 2000-2019 were included. Treatment types included; living donor; standard criteria donor (SCD); ECD60 (deceased donor aged ≥60 years); ECD50-59 (deceased donor aged 50-59 years with two from the following three; hypertension; raised creatinine and/or death from stroke) or remains on dialysis. The primary outcome was all-cause mortality, with time-to-death from listing analyzed using time-dependent non-proportional Cox regression models. The study cohort comprised 47,917 waitlisted kidney failure patients, of whom 34,558 (72.1%) received kidney transplantation. ECD kidneys (n = 7,356) were stratified as ECD60 (n = 7,009) or ECD50-59 (n = 347). Compared to SCD, both ECD60 (Hazard Ratio 1.126, 95% CI 1.093-1.161) and ECD50-59 (Hazard Ratio 1.228, 95% CI 1.113-1.356) kidney recipients have higher all-cause mortality. However, compared to dialysis, both ECD60 (Hazard Ratio 0.194, 95% CI 0.187-0.201) and ECD50-59 (Hazard Ratio 0.218, 95% CI 0.197-0.241) kidney recipients have lower all-cause mortality. ECD kidneys, regardless of definition, provide equivalent and superior survival benefits in comparison to remaining waitlisted.

Kidney Bioengineering for Transplantation

The kidney is an important organ for maintenance of homeostasis in the human body. As renal failure progresses, renal replacement therapy becomes necessary. However, there is a chronic shortage of kidney donors, creating a major problem for transplantation. To solve this problem, many strategies for the generation of transplantable kidneys are under investigation. Since the first reports describing that nephron progenitors could be induced from human induced pluripotent stem cells, kidney organoids have been attracting attention as tools for studying human kidney development and diseases. Because the kidney is formed through the interactions of multiple renal progenitors, current studies are investigating ways to combine these progenitors derived from human induced pluripotent stem cells for the generation of transplantable kidney organoids. Other bioengineering strategies, such as decellularization and recellularization of scaffolds, 3-dimensional bioprinting, interspecies blastocyst complementation and progenitor replacement, and xenotransplantation, also have the potential to generate whole kidneys, although each of these strategies has its own challenges. Combinations of these approaches will lead to the generation of bioengineered kidneys that are transplantable into humans.

Long and Short-Term Effects of Hypothermic Machine Perfusion vs. Cold Storage on Transplanted Kidneys from Expanded Criteria Donors-A Matched Comparison Study

Hypothermic machine perfusion (HMP) has been shown to reduce delayed graft function (DGF)-rates in kidneys from expanded criteria donors (ECD) and may increase graft survival compared with static cold storage (SCS). This single-center, retrospective observational study aimed to evaluate this effect. The primary endpoint was the DGF-rate, defined as the use of dialysis in the first postoperative week, excluding the first 24 h. The main secondary endpoint was graft survival at 5 years. Recipients of ECD-kidneys between 2013 and 2021 with ≤2 grafts were included (n = 438). The SCS-kidneys were marginal-matched by propensity score to the HMP-group for donor age, cold ischemia time, and graft number. Multivariable adjusted analysis for confounders in the unmatched cohort and caliper-based ID-matching constituted sensitivity analyses. HMP showed a trend to lower DGF-rate in the marginal-matched comparison (9.2% vs. 16.1%, p = 0.063). This was strengthened by a significant benefit observed for HMP in both the sensitivity analyses: an adjusted OR of 0.45 (95% CI: 0.24; 0.84; p = 0.012) in the multivariable analysis and DGF-rate of 8.7% vs. 17.4% (p = 0.024) after ID-matching. The 5-year graft survival rate was >90% in both groups, with no benefit using HMP (HR = 0.79; 95% CI:0.39-1.16; p = 0.52). Our results suggest that HMP may be effective in decreasing DGF-rates, however, without any significant benefit in graft survival.

The first use of hypothermic machine perfusion in Korea to recover a procured kidney graft and prevent prolonged cold ischemic time: a case report

To overcome the shortage of donor grafts in kidney transplantation (KT), the use of marginal grafts has evolved. However, prolonged cold ischemic time (CIT) is especially critical when using marginal grafts. Recently, hypothermic machine perfusion (HMP) has been used to overcome the negative effects of prolonged CIT, and we report the first use of HMP in Korea. The donor was a 58-year-old man with severe hypoxia (PaO₂ <60 mmHg, FiO₂ 100%) for 9 hours prior to procurement. The patient's kidneys were the only organs accepted for transplantation, and both kidneys were assigned to Jeju National University Hospital. After procurement, the right kidney was preserved using HMP immediately, and the left kidney was directly transplanted into a patient with a CIT of 2 hours 31 minutes. The second operation was performed following the first, using the right kidney graft that had been preserved by HMP for 10 hours and 30 minutes. Although postoperative graft function gradually recovered in both patients, the serum creatinine level decreased faster in the HMP patient. Neither patient showed signs of delayed graft function, and both were discharged without significant complications. The short-term outcomes in this transplantation of mate kidney grafts demonstrated that graft function can be safely preserved using HMP, and that HMP is beneficial in overcoming the negative effects of prolonged CIT.

Outcomes of Kidney Perfusion Techniques in Transplantation from Deceased Donors: A Systematic Review and Meta-Analysis

The high demand for organs in kidney transplantation and the expansion of the donor pool have led to the widespread implementation of machine perfusion technologies. In this study, we aim to provide an up-to-date systematic review of the developments in this expanding field over the past 10 years, with the aim of answering the question: "which perfusion technique is the most promising technique in kidney transplantation?" A systematic review of the literature related to machine perfusion in kidney transplantation was performed. The primary outcome measure was delayed graft function (DGF), and secondary outcomes included rates of rejection, graft survival, and patient survival rates after 1 year. Based on the available data, a meta-analysis was performed. The results were compared with data from static cold storage, which is still the standard of care in many centers worldwide. A total of 56 studies conducted in humans were included, and 43 studies reported outcomes of hypothermic machine perfusion (HMP), with a DGF rate of 26.4%. A meta-analysis of 16 studies showed significantly lower DGF rates in the HMP group compared to those of static cold storage (SCS). Five studies reported outcomes of hypothermic machine perfusion + O₂, with an overall DGF rate of 29.7%. Two studies explored normothermic machine perfusion (NMP). These were pilot studies, designed to assess the feasibility of this perfusion approach in the clinical setting. Six studies reported outcomes of normothermic regional perfusion (NRP). The overall incidence of DGF was 71.5%, as it was primarily used in uncontrolled DCD (Maastricht category I-II). Three studies comparing NRP to in situ cold perfusion showed a significantly lower rate of DGF with NRP. The systematic review and meta-analysis provide evidence that dynamic preservation strategies can improve outcomes following kidney transplantation. More recent approaches such as normothermic machine perfusion and hypothermic machine perfusion + O₂ do show promising results but need further results from the clinical setting. This study shows that the implementation of perfusion strategies could play an important role in safely expanding the donor pool.

Midterm Outcomes of Kidney Transplantation from Expanded Criteria Donors After Circulatory Death: A Single-Center Retrospective Cohort Study

OBJECTIVES

Kidney transplant is the optimal treatment for end-stage renal disease; however, due to the imbalance between demand and supply, several strategies have been implemented to increase the donor pool. To increase the number of donors, expanded criteria donors after circulatory death have been explored as an acceptable graft source. In this study, we compared graft survival, estimated glomerular filtration rate at 3 and 5 years, and the incidence of delayed graft function between standard and expanded criteria donors after brain death and between standard and expanded criteria donors after circulatory death.

MATERIALS AND METHODS

A prospective cohort study was conducted between January 1, 2015, and December 31, 2019, at Reina Sofia University Hospital. Variables related to the donor, recipient, and transplant procedure were analyzed, and univariate and multivariate logistic and Cox regression analyses were performed.

RESULTS

Our study included 308 deceased donor kidneys. The kidneys from standard criteria brain dead donors had higher estimated glomerular filtration rate than the other groups (P < .03).However, no significant differences in estimated glomerular filtration rate were observed among the suboptimal groups (expanded criteria and standard criteria donors after brain death and expanded criteria donors after circulatory death). The incidence of delayed graft function was significantly higher in expanded criteria donors after circulatory death than in the other groups (odds ratio = 6.9; 95% CI, 2.22-21.71; P < .001). Nevertheless, we found no significant differences in death-censored graft loss among the groups.

CONCLUSIONS

Kidney transplants from expanded criteria donors and donors after cardiac death are comparable, even when both criteria are combined. The use of expanded criteria donor kidneys after cardiac death is therefore a suitable approach to expand the donor pool, despite the higher risk of delayed graft function, as there were no significant differences in death-censored graft loss.

Association of the Calcification Score of the Abdominal Aorta, Common Iliac, and Renal Arteries with Outcomes in Living Kidney Donors

BACKGROUND

Vascular calcification is an ever-more-common finding in protocoled pre-transplant imaging in living kidney donors. We intended to explore whether a connection could be found between the Agatston calcification score, prior to kidney donation, and post-donation renal function.

METHODS

This is a retrospective analysis of 156 living kidney donors who underwent living donor nephrectomy between January 2010 and December 2016. We quantified the total calcification score (TCaScore) by calculating the Agatston score for each vessel, abdominal aorta, common iliac, and renal arteries. Donors were placed into two different groups based on their TCaScore: <100 TCaScore group and ≥100 TCaScore group. The relationship between TCaScore, 1-year eGFR, proteinuria, and risk of 1 measurement of decreased renal function (eGFR < 60 mL/min/1.73 m²) over 5 years of follow-up was investigated.

RESULTS

The ≥100 TCaScore group consisted of 29 (19%) donors, with a median (interquartile range) calcification score of 164 (117-358). This group was significantly older, 56.7 ± 6.9 vs. 45.5 ± 10.6 (p < 0.001), had a higher average BMI (p < 0.019), and had a lower preoperative eGFR (p < 0.014). The 1-year eGFR was similarly diminished, 69.9 ± 15.7 vs. 76.3 ± 15.5 (p < 0.048), while also having an increased risk of decreased renal function during the follow-up, 22% vs. 48% (p < 0.007).

CONCLUSIONS

Our study, through univariate analyses, found a relationship between a TCaScore > 100, lower 1-year eGFR, and decreased renal function in 5 years. However, a higher-than-expected vascular calcification should not be an excluding factor in donors, although they may require closer monitoring during follow-up.

Kidney transplantation from elderly donors (> 70 years): a systematic review

PURPOSE

The incidence of kidney transplants from elderly donors over 70 years of age has increased significantly over the past 10 years to reach 20% of available kidney graft in some European countries. However, there is little data available on the outcomes of transplants from these donors. We performed a systematic review to evaluate the outcomes of transplantation from donors over 70 years of age.

METHODS

A systematic review was performed according to preferred reporting items for systematic reviews and meta-analyses. Medline, Embase, and Cochrane databases were searched to identify all studies reporting outcomes on kidney transplants from donors over 70 years. Due to the heterogeneity of the studies, a meta-analysis could not be performed.

RESULTS

A total of 29,765 patients in 27 studies were included. The mean donors age was 74.79 years, and proportion of kidney graft from women was 53.54%. The estimated 1- and 5-year kidney death-censored graft survivals from donors > 70 years old were, respectively, 85.95 and 80.27%, and the patient survivals were 90.88 and 71.29%. The occurrence of delayed graft function was 41.75%, and primary non-function was 4.67%. Estimated graft function at 1 and 5 years was 36 and 38 mL/min/1.73 m². Paucity data were available on post-operative complications.

CONCLUSIONS

Elderly donors appear to be a reliable source of grafts. However, these transplants are associated with a high rate of delayed graft function without repercussion on long-term graft survival. Allocation strategy to elderly recipients is the main factor of decreased recipient survival.

Effect of blood transfusion post kidney transplantation on de novo human leukocytes antigen donor-specific antibody development and clinical outcomes in kidney transplant recipients: A systematic review and meta-analysis

The relationship between blood transfusion following kidney transplantation (KT) and the development of de novo donor-specific antibodies (dnDSA) is controversial. This was investigated by conducting a meta-analysis of studies on patients who underwent KT with or without blood transfusion, and by evaluating the effect of post-KT blood transfusion on clinical outcomes of kidney transplant recipients. Relevant studies in the PubMed, EMBASE, and Cochrane Library databases were identified from inception to July 1, 2022. Two reviewers independently extracted data from the selected articles and estimated study quality. A fixed effects or random effects model was used to pool data according to the heterogeneity among studies. Data included in the meta-analysis were derived from 11 studies with a total of 19,543 patients including 6191 with and 13,352 without blood transfusion post-KT. We assessed the pooled associations between blood transfusion and occurrence of dnDSA and clinical outcomes of transplant recipients. Blood transfusion was strongly correlated with the development of dnDSA (relative risk [RR] = 1.40, 95% confidence interval [CI]: 1.17-1.67; P < 0.05). Patients with blood transfusion had a higher risk of developing anti-human leukocyte antigen (HLA) class I dnDSA than non-transfused patients (RR = 1.75, 95% CI: 1.14-2.69; P < 0.05) as well as significantly higher rates of antibody-mediated rejection (AMR) (RR = 1.41, 95% CI: 1.21-2.35; P < 0.05) and graft loss (RR = 1.75, 95% CI: 1.30-2.35; P < 0.05). There were no statistically significant differences between the two groups in the development of anti-HLA antibodies, anti-HLA class II dnDSA, and anti-HLA class I and II dnDSA; delayed graft function; T cell-mediated rejection; acute rejection; borderline rejection; or patient death. Our results suggest that blood transfusion was associated with dnDSA development in KT recipients. The findings of this systematic review also suggest that post-KT blood transfusion recipients have a higher risk of AMR, and graft loss compared with non-transfused patients. Evidence from this meta-analysis indicates that the use of blood transfusion post-KT is associated with a significantly higher risk of immunological sensitization. More and higher quality results from large randomized controlled trials are still needed to inform clinical practice.

Deceased Donor Kidney Transplantation From Donors With Acute Kidney Injury: Realities and Costs

OBJECTIVES

Transplant of kidneys from donors with acute kidney injury has shown favorable outcomes. We investigated the outcomes of kidney transplant recipients with deceased donors who developed acute kidney injury before organ procurement.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of recipients from January 2016 to December 2021 in a single center. Outcomes in recipients of kidney grafts from donors with and without acute kidney injury were compared.

RESULTS

The mean follow-up time was 40 months. Our study included 129 (34%) kidneys transplanted from donors with acute kidney injury and 251 (66%) kidneys from donors without acute kidney injury. Delayed graft function rate in recipients was 33% in the acute kidney injury group and 25.5% in the group without acute kidney injury (P = .099). Readmission rate at 30 days was significantly higher among recipients of kidneys with acute kidney injury compared with recipients of kidneys without acute kidney injury (45% vs 33.5%; P = .02). The mean overall costs of transplant in the acute kidney injury group were comparable to the group without acute kidney injury ($253 865 vs $253 611; P = .97). The acute rejection rate was comparable between the 2 groups (4% in both groups; P = .96). Delayed graft function rate was increased with increased stage of acute kidney injury (18% stage 1, 45% stage 2, 36% stage 3; P = .03). However, the overall length of hospital stay and costs were comparable among recipients of different stages of acute kidney injury.

CONCLUSIONS

Our study showed that kidney transplants from donors with acute kidney injury have early and late outcomes comparable to kidney transplants from donors without acute kidney injury. Allografts from donors with acute kidney injury can be used safely and can expand the donor pool in kidney transplant without increasing perioperative resource utilization.

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.

Investigation of Different Methods of Intraoperative Graft Perfusion Assessment during Kidney Transplantation for the Prediction of Delayed Graft Function: A Prospective Pilot Trial

Delayed graft function (DGF) after renal transplantation is a relevant clinical problem affecting long-term organ function. The early detection of patients at risk is crucial for postoperative monitoring and treatment algorithms. In this prospective cohort study, allograft perfusion was evaluated intraoperatively in 26 kidney recipients by visual and formal perfusion assessment, duplex sonography, and quantitative microperfusion assessment using O2C spectrometry and ICG fluorescence angiography. The O2C tissue spectrometry device provides a quantitative method of microperfusion assessment that can be employed during kidney transplantation as an easy-to-use and highly sensitive alternative to ICG fluorescence angiography. Intraoperative microvascular flow and velocity in the allograft cortex after reperfusion predicted DGF with a sensitivity of 100% and a specificity of 82%. Threshold values of 57 A.U. for microvascular flow and 13 A.U. for microvascular velocity were identified by an ROC analysis. This study, therefore, confirmed that impairment of microperfusion of the allograft cortex directly after reperfusion was a key indicator for the occurrence of DGF after kidney transplantation. Our results support the combined use of intraoperative duplex sonography, for macrovascular quality control, and quantitative microperfusion assessment, such as O2C spectrometry, for individual risk stratification to guide subsequent postoperative management.

Normothermic machine perfusion of kidneys: current strategies and future perspectives

PURPOSE OF REVIEW

This review aims to summarize the latest original preclinical and clinical articles in the setting of normothermic machine perfusion (NMP) of kidney grafts.

RECENT FINDINGS

Kidney NMP can be safely translated into the clinical routine and there is increasing evidence that NMP may be beneficial in graft preservation especially in marginal kidney grafts. Due to the near-physiological state during NMP, this technology may be used as an ex-vivo organ assessment and treatment platform. There are reports on the application of mesenchymal stromal/stem cells, multipotent adult progenitor cells and microRNA during kidney NMP, with first data indicating that these therapies indeed lead to a decrease in inflammatory response and kidney injury. Together with the demonstrated possibility of prolonged ex-vivo perfusion without significant graft damage, NMP could not only be used as a tool to perform preimplant graft assessment. Some evidence exists that it truly has the potential to be a platform to treat and repair injured kidney grafts, thereby significantly reducing the number of declined organs.

SUMMARY

Kidney NMP is feasible and can potentially increase the donor pool not only by preimplant graft assessment, but also by ex-vivo graft treatment.

Delayed Graft Function in Kidney Transplant: Risk Factors, Consequences and Prevention Strategies

Background. Delayed graft function is a frequent complication of kidney transplantation that requires dialysis in the first week posttransplant. Materials and Methods. We searched for the most relevant articles in the National Institutes of Health library of medicine, as well as in transplantation, pharmacologic, and nephrological journals. Results. The main factors that may influence the development of delayed graft function (DGF) are ischemia–reperfusion injury, the source and the quality of the donated kidney, and the clinical management of the recipient. The pathophysiology of ischemia–reperfusion injury is complex and involves kidney hypoxia related to the duration of warm and cold ischemia, as well as the harmful effects of blood reperfusion on tubular epithelial cells and endothelial cells. Ischemia–reperfusion injury is more frequent and severe in kidneys from deceased donors than in those from living donors. Of great importance is the quality and function of the donated kidney. Kidneys from living donors and those with normal function can provide better results. In the peri-operative management of the recipient, great attention should be paid to hemodynamic stability and blood pressure; nephrotoxic medicaments should be avoided. Over time, patients with DGF may present lower graft function and survival compared to transplant recipients without DGF. Maladaptation repair, mitochondrial dysfunction, and acute rejection may explain the worse long-term outcome in patients with DGF. Many different strategies meant to prevent DGF have been evaluated, but only prolonged perfusion of dopamine and hypothermic machine perfusion have proven to be of some benefit. Whenever possible, a preemptive transplant from living donor should be preferred.

Deceased Donor Characteristics and Kidney Transplant Outcomes

Kidney transplantation is the therapy of choice for people living with kidney failure who are suitable for surgery. However, the disparity between supply versus demand for organs means many either die or are removed from the waiting-list before receiving a kidney allograft. Reducing unnecessary discard of deceased donor kidneys is important to maximize utilization of a scarce and valuable resource but requires nuanced decision-making. Accepting kidneys from deceased donors with heterogenous characteristics for waitlisted kidney transplant candidates, often in the context of time-pressured decision-making, requires an understanding of the association between donor characteristics and kidney transplant outcomes. Deceased donor clinical factors can impact patient and/or kidney allograft survival but risk-versus-benefit deliberation must be balanced against the morbidity and mortality associated with remaining on the waiting-list. In this article, the association between deceased kidney donor characteristics and post kidney transplant outcomes for the recipient are reviewed. While translating this evidence to individual kidney transplant candidates is a challenge, emerging strategies to improve this process will be discussed. Fundamentally, tools and guidelines to inform decision-making when considering deceased donor kidney offers will be valuable to both professionals and patients.

Normothermic Ex Vivo Kidney Perfusion for Human Kidney Transplantation: First North American Results

BACKGROUND

Normothermic ex vivo kidney perfusion (NEVKP) has shown promising results for preservation, assessment, and reconditioning of kidney allografts in preclinical studies. Here, we report the first North American safety and feasibility study of deceased donor kidneys grafts transplanted following preservation with NEVKP.

METHODS

Outcomes of 13 human kidney grafts that received 1 to 3 h of NEVKP after being transported in an anoxic hypothermic machine perfusion device were compared with a matched control group of 26 grafts that were preserved with anoxic hypothermic machine perfusion alone.

RESULTS

Grafts were perfused for a median of 171 min (range, 44-275 min). The delayed graft function rate in NEVKP versus control patients was 30.8% versus 46.2% (P = 0.51). During the 1-y follow-up, no differences in postoperative graft function, measured by serum creatinine, necessity for dialysis, and urine production, were found between the study group and the control group. There were no differences in 1 y posttransplantation graft or patient survival between the 2 groups.

CONCLUSIONS

Our study demonstrates the safety and feasibility of NEVKP for human deceased donor kidney transplantation. Further studies are warranted to explore how this technology can minimize cold ischemia, improve posttransplant graft function, and assess and repair expanded criteria kidney grafts.

Desenlaces a largo plazo en pacientes trasplantados renales con donantes de criterios expandidos: experiencia de 10 años

Introducción. El trasplante renal es el tratamiento de elección para la enfermedad renal crónica. Debido a la brecha con la disponibilidad de donantes, el uso de criterios expandidos es una opción que busca mejorar la tasa de donación mundial. El objetivo de este estudio fue comparar la sobrevida del injerto y del paciente trasplantado con donante de criterios expandidos versus el donante estándar. Métodos. Cohorte retrospectiva de 1002 pacientes con trasplante renal donde se determinó la sobrevida del injerto renal y del receptor a 10 años después del trasplante. La sobrevida del injerto renal y el receptor fueron estimadas por el método de Kaplan-Meier. Una regresión de Cox fue realizada ajustando el modelo multivariado. Resultados. El análisis incluyó 1002 receptores, con un 18,8 % (n=189) que correspondían al uso de donante de criterios expandidos. El grupo de trasplante renal con donante de criterios expandidos tuvo menor sobrevida del paciente (48,1 % versus 63,8 %) y del injerto (63,3 % versus 74,7 %) en comparación con el grupo de trasplante renal con donantes con criterios estándar a los 10 años después del trasplante. La asociación de trasplante renal con donante de criterios expandidos y muerte o pérdida del injerto renal no fueron significativas cuando se ajustaron las variables en el modelo multivariado. Conclusión. El trasplante renal con donante de criterios expandidos tiene menor sobrevida del receptor y del injerto frente al grupo de trasplante renal con donante estándar. No hubo diferencias estadísticamente significativas en cuanto al trasplante renal con donante de criterios expandidos frente a la pérdida del injerto renal o muerte.

Clinical use of controlled oxygenated rewarming of kidney grafts prior to transplantation by ex vivo machine perfusion. A pilot study

BACKGROUND

Sudden restoration of normothermic conditions upon reperfusion of cold-stored grafts has been suggested to entail a massive energy demand not yet met by the cells that still suffer from hypothermic torpor. An adapted and gentle rise of graft temperature by ex-vivo machine perfusion has, therefore, been proposed. This should now be tested in the clinical setting.

METHODS

In a first clinical series, six ECD-kidneys were subjected to controlled oxygenated rewarming (COR) during short term pre-implantation machine perfusion. Matched kidneys that were conventionally kept on ice served as controls.

RESULTS

Early allograft function after transplantation was significantly improved by COR. On post-operative day 7, clearance of creatinine was more than twofold higher after COR and fractional excretion of sodium in the normal range, while significantly elevated in control kidneys. Good correlations were seen between ulterior graft function and real-time parameters obtained during pre-transplant machine perfusion (Lactate: r²  = .9; TIMP2: r²  = .74). Conventional denominators of graft viability like kidney donor risk index KDRI were far less predictive (r²  = .26).

CONCLUSION

It is concluded that COR can be safely applied to renal grafts and appears to be a valuable tool to predict and improve early renal function after transplantation.

The use of marginal kidneys in dual kidney transplantation to expand kidney graft utilization

PURPOSE OF REVIEW

The purpose of this review is to chronicle the history of dual kidney transplantation (DKT) and identify opportunities to improve utilization of marginal deceased donor (MDD) kidneys through DKT.

RECENT FINDINGS

The practice of DKT from adult MDDs dates back to the mid-1990s, at which time the primary indication was projected insufficient nephron mass from older donors. Multiple subsequent studies of short- and long-term success have been reported focusing on three major aspects: Identifying appropriate selection criteria/scoring systems based on pre- and postdonation factors; refining technical aspects; and analyzing longer-term outcomes. The number of adult DKTs performed in the United States has declined in the past decade and only about 60 are performed annually. For adult deceased donor kidneys meeting double allocation criteria, >60% are ultimately not transplanted. MDDs with limited renal functional capacity represent a large proportion of potential kidneys doomed to either discard or nonrecovery.

SUMMARY

DKT may reduce organ discard and optimize the use of kidneys from MDDs. New and innovative technologies targeting ex vivo organ assessment, repair, and regeneration may have a major impact on the decision whether or not to use recovered kidneys for single or DKT.

Dual kidney transplants from adult marginal donors: Review and perspective

The practice of dual kidney transplantation (DKT) from adult marginal deceased donors (MDDs) dates back to the mid-1990s with initial pioneering experiences reported by the Stanford and Maryland groups, at which time the primary indication was estimated insufficient nephron mass from older donors. Multiple subsequent studies of short and long-term success have been reported focusing on three major aspects of DKT: Identifying appropriate selection criteria and developing scoring systems based on pre- and post-donation factors; refining technical aspects; and analyzing mid-term outcomes. The number of adult DKTs performed in the United States has declined in the past decade and only about 60 are performed annually. For adult deceased donor kidneys meeting double allocation criteria, >60% are ultimately not transplanted. Deceased donors with limited renal functional capacity represent a large proportion of potential kidneys doomed to either discard or non-recovery. However, DKT may reduce organ discard and optimize the use of kidneys from MDDs. In an attempt to promote utilization of MDD kidneys, the United Network for Organ Sharing introduced new allocation guidelines pursuant to DKT in 2019. The purpose of this review is to chronicle the history of DKT and identify opportunities to improve utilization of MDD kidneys through DKT. This article is protected by copyright. All rights reserved.

Impact of the explanting surgeon's impression of donor arteriosclerosis on outcome of kidney transplantations from donors aged ≥65 years

PURPOSE

Careful donor selection is important for kidney transplantations (KT) from suboptimal donors aged ≥65 years. Several tools such as histopathological assessment of preimplant biopsies have been shown to predict allograft survival and can be applied for selection. Whether the explanting surgeon's appraisal is associated with outcomes of KTs from suboptimal donors is unknown.

METHODS

We compared outcomes of KTs from ≥65-year-old deceased donors performed at our centre between 1999 and 2018 for which grading of macroscopic 'donor arteriosclerosis' (n=104) and 'organ quality' (n=208) as judged by the explanting surgeon and documented on the Eurotransplant kidney organ report was available.

RESULTS

No association was observed between degree of macroscopic donor arteriosclerosis and death-censored graft survival in univariable or multivariable regression analyses. Compared to KTs from donors with no/mild arteriosclerosis, KTs from donors with moderate/severe arteriosclerosis were associated with a significantly impaired allograft function 3 months, 1 year and 3 years after transplantation (e.g. at 3 years: 176.8 µmol/l vs 137.0 µmol/l, P=0.003). Following multivariable regression analysis, these differences remained significant at 3 months and 3 years after KT. No association was observed between degree of macroscopic arteriosclerosis and mortality or primary non-function as well as no consistent association with delayed graft function and histological arteriosclerosis. Assessment of 'organ quality' was not associated with outcomes.

CONCLUSION

Our data suggest that the explanting surgeon's assessment of donor arteriosclerosis is associated with allograft function. Larger studies and better standardization of kidney inspection after explantation are required to further explore the impact of surgeon's appraisal in KT.

Combating Ischemia-Reperfusion Injury with Micronutrients and Natural Compounds during Solid Organ Transplantation: Data of Clinical Trials and Lessons of Preclinical Findings

Although extended donor criteria grafts bear a higher risk of complications such as graft dysfunction, the exceeding demand requires to extent the pool of potential donors. The risk of complications is highly associated with ischemia-reperfusion injury, a condition characterized by high loads of oxidative stress exceeding antioxidative defense mechanisms. The antioxidative properties, along with other beneficial effects like anti-inflammatory, antiapoptotic or antiarrhythmic effects of several micronutrients and natural compounds, have recently emerged increasing research interest resulting in various preclinical and clinical studies. Preclinical studies reported about ameliorated oxidative stress and inflammatory status, resulting in improved graft survival. Although the majority of clinical studies confirmed these results, reporting about improved recovery and superior organ function, others failed to do so. Yet, only a limited number of micronutrients and natural compounds have been investigated in a (large) clinical trial. Despite some ambiguous clinical results and modest clinical data availability, the vast majority of convincing animal and in vitro data, along with low cost and easy availability, encourage the conductance of future clinical trials. These should implement insights gained from animal data.

Multicenter registry analysis comparing survival on home hemodialysis and kidney transplant recipients in Australia and New Zealand

BACKGROUND

In the era of organ shortage, home hemodialysis (HHD) has been identified as the possible preferential bridge to kidney transplantation. Data are conflicting regarding the comparability of HHD and transplantation outcomes. This study aimed to compare patient and treatment survival between HHD patients and kidney transplant recipients.

METHODS

The Australia and New Zealand Dialysis and Transplant Registry was used to include incident HHD patients on Day 90 after initiation of kidney replacement therapy and first kidney-only transplant recipients in Australia and New Zealand from 1997 to 2017. Survival times were analyzed using the Kaplan-Meier product-limit method comparing HHD patients with subtypes of kidney transplant recipients using the log-rank test. Adjusted analyses were performed with multivariable Cox proportional hazards regression models for time to all-cause mortality. Time-to-treatment failure or death was assessed as a composite secondary outcome.

RESULTS

The study compared 1411 HHD patients with 4960 living donor (LD) recipients, 6019 standard criteria donor (SCD) recipients and 2427 expanded criteria donor (ECD) recipients. While LD and SCD recipients had reduced risks of mortality compared with HHD patients [LD adjusted hazard ratio (HR) = 0.57, 95% confidence interval (CI) 0.46-0.71; SCD HR = 0.65 95% CI 0.52-0.79], the risk of mortality was comparable between ECD recipients and HHD patients (HR = 0.90, 95% CI 0.73-1.12). LD, SCD and ECD kidney recipients each experienced superior time-to-treatment failure or death compared with HHD patients.

CONCLUSIONS

This large registry study showed that kidney transplant offers a survival benefit compared with HHD but that this advantage is not significant for ECD recipients.

Prolonged Normothermic Ex Vivo Kidney Perfusion Is Superior to Cold Nonoxygenated and Oxygenated Machine Perfusion for the Preservation of DCD Porcine Kidney Grafts

The increased usage of marginal grafts has triggered interest in perfused kidney preservation to minimize graft injury. We used a donation after circulatory death (DCD) porcine kidney autotransplantation model to compare 3 of the most frequently used ex vivo kidney perfusion techniques: nonoxygenated hypothermic machine perfusion (non-oxHMP), oxygenated hypothermic machine perfusion (oxHMP), and normothermic ex vivo kidney perfusion (NEVKP).

Methods

Following 30 min of warm ischemia, grafts were retrieved and preserved with either 16 h of non-oxHMP, oxHMP, or NEVKP (n = 5 per group). After contralateral nephrectomy, grafts were autotransplanted and animals were followed for 8 d. Kidney function and injury markers were compared between groups.

Results

NEVKP demonstrated a significant reduction in preservation injury compared with either cold preservation method. Grafts preserved by NEVKP showed superior function with lower peak serum creatinine (NEVKP versus non-oxHMP versus oxHMP: 3.66 ± 1.33 mg/dL, 8.82 ± 3.17 mg/dL, and 9.02 ± 5.5 mg/dL) and more rapid recovery. The NEVKP group demonstrated significantly increased creatinine clearance on postoperative day 3 compared with the cold perfused groups. Tubular injury scores on postoperative day 8 were similar in all groups.

Conclusions

Addition of oxygen during HMP did not reduce preservation injury of DCD kidney grafts. Grafts preserved with prolonged NEVKP demonstrated superior initial graft function compared with grafts preserved with non-oxHMP or oxHMP in a model of pig DCD kidney transplantation.

Retrospective Analysis of the Kidney Donor Profile Index to Predict Patient and Graft Survival at 5 Years Posttransplantation in a Colombian Cohort

BACKGROUND

The Kidney Donor Profile Index (KDPI) has been used to predict patient and graft outcomes in deceased donor kidney transplantation. We aimed to evaluate the impact of KDPI on transplantation major outcomes applied to a Colombian cohort.

METHODS

We retrospectively assessed 260 adult patients who underwent kidney transplantation (KT) from January 2011 to June 2014 at our center and compared their KDPIs with graft and patient outcomes at 5 years posttransplantation. Kaplan-Meier survival method and Cox analysis were fitted to analyze the impact of the 3 KDPI categories on graft and patient outcomes.

RESULTS

A total of 18.4% of transplants were from donors with a KDPI ≥75%. There was a significant decrement in renal function with increasing KDPI at 5 years posttransplantation (P < .05). The final model indicates that donor diabetes was associated with elevated risk for graft loss (hazard ratio [HR], 6.5; 95% confidence interval [CI] 1.35-31.8; P = .019) at 5 years posttransplantation. Recipient age (HR, 2.3; 95% CI, 1.1-4.5; P = .001), diabetes status (HR, 2.17; CI, 1.04-5.5; P = .003), dialysis duration (HR, 1.08; 95% CI, 1.00-1.16; P = .003), and operating room time (HR, 1.47; 95% CI, 1.02-2.12; P = .003) were associated with elevated risk for death at 5 years posttransplantation. KDPI categories were not significantly associated with graft loss or death.

CONCLUSIONS

We found limited KDPI power to predict graft and patient survival when applied to a Latin American population in Colombia. Our findings highlight the importance of analyzing the application of KDPI in different populations. Therefore, our findings may not be generalizable to other regions outside of Colombia.

Outcomes and factors leading to graft failure in kidney transplants from deceased donors with acute kidney injury-A retrospective cohort study

Due to shortage of donor, kidney transplants (KTs) from donors with acute kidney injury (AKI) are expanding. Although previous studies comparing clinical outcomes between AKI and non-AKI donors in KTs have shown comparable results, data on high-volume analysis of KTs outcomes with AKI donors are limited. This study aimed to analyze the selection trends of AKI donors and investigate the impact of AKI on graft failure using the United states cohort data. We analyzed a total 52,757 KTs collected in the Scientific Registry of Transplant Recipient (SRTR) from 2010 to 2015. The sample included 4,962 (9.4%) cases of KTs with AKI donors (creatinine ≥ 2 mg/dL). Clinical characteristics of AKI and non-AKI donors were analyzed and outcomes of both groups were compared. We also analyzed risk factors for graft failure in AKI donor KTs. Although the incidence of delayed graft function was higher in recipients of AKI donors compared to non-AKI donors, graft and patient survival were not significantly different between the two groups. We found donor hypertension, cold ischemic time, the proportion of African American donors, and high KDPI were risk factors for graft failure in AKI donor KTs. KTs from deceased donor with AKI showed comparable outcomes. Thus, donors with AKI need to be considered more actively to expand donor pool. Caution is still needed when donors have additional risk factors of graft failure.

Does kidney transplantation with a standard or expanded criteria donor improve patient survival? Results from a Belgian cohort

BACKGROUND

Changes in recipient and donor factors have reopened the question of survival benefits of kidney transplantation versus dialysis.

METHODS

We analysed survival among 3808 adult Belgian patients waitlisted for a first deceased donor kidney transplant from 2000 to 2012. The primary outcome was mortality during the median waiting time plus 3 years of follow-up after transplantation or with continued dialysis. Outcomes were analysed separately for standard criteria donor (SCD) and expanded criteria donor (ECD) kidney transplants. We adjusted survival analyses for recipient age (20-44, 45-64 and ≥65 years), sex and diabetes as the primary renal disease.

RESULTS

Among patients ≥65 years of age, only SCD transplantation provided a significant survival benefit compared with dialysis, with a mortality of 16.3% [95% confidence interval (CI) 13.2-19.9] with SCD transplantation, 20.5% (95% CI 16.1-24.6) with ECD transplantation and 24.6% (95% CI 19.4-29.5) with continued dialysis. Relative mortality risk was increased in the first months after transplantation compared with dialysis, with equivalent risk levels reached earlier with SCD than ECD transplantation in all age groups.

CONCLUSIONS

The results of this study suggest that older patients might gain a survival benefit with SCD transplantation versus dialysis, but any survival benefit with ECD transplantation versus dialysis may be small.

Oxygenated End-Hypothermic Machine Perfusion in Expanded Criteria Donor Kidney Transplant: A Randomized Clinical Trial

IMPORTANCE

Continuous hypothermic machine perfusion during organ preservation has a beneficial effect on graft function and survival in kidney transplant when compared with static cold storage (SCS).

OBJECTIVE

To compare the effect of short-term oxygenated hypothermic machine perfusion preservation (end-HMPo2) after SCS vs SCS alone on 1-year graft survival in expanded criteria donor kidneys from donors who are brain dead.

DESIGN, SETTING, AND PARTICIPANTS

In a prospective, randomized, multicenter trial, kidneys from expanded criteria donors were randomized to either SCS alone or SCS followed by end-HMPo2 prior to implantation with a minimum machine perfusion time of 120 minutes. Kidneys were randomized between January 2015 and May 2018, and analysis began May 2019. Analysis was intention to treat.

INTERVENTIONS

On randomization and before implantation, deceased donor kidneys were either kept on SCS or placed on HMPo2.

MAIN OUTCOME AND MEASURES

Primary end point was 1-year graft survival, with delayed graft function, primary nonfunction, acute rejection, estimated glomerular filtration rate, and patient survival as secondary end points.

RESULTS

Centers in 5 European countries randomized 305 kidneys (median [range] donor age, 64 [50-84] years), of which 262 kidneys (127 [48.5%] in the end-HMPo2 group vs 135 [51.5%] in the SCS group) were successfully transplanted. Median (range) cold ischemia time was 13.2 (5.1-28.7) hours in the end-HMPo2 group and 12.9 (4-29.2) hours in the SCS group; median (range) duration in the end-HMPo2 group was 4.7 (0.8-17.1) hours. One-year graft survival was 92.1% (n = 117) in the end-HMPo2 group vs 93.3% (n = 126) in the SCS group (95% CI, -7.5 to 5.1; P = .71). The secondary end point analysis showed no significant between-group differences for delayed graft function, primary nonfunction, estimated glomerular filtration rate, and acute rejection.

CONCLUSIONS AND RELEVANCE

Reconditioning of expanded criteria donor kidneys from donors who are brain dead using end-HMPo2 after SCS does not improve graft survival or function compared with SCS alone. This study is underpowered owing to the high overall graft survival rate, limiting interpretation.

TRIAL REGISTRATION

isrctn.org Identifier: ISRCTN63852508.

Transplantation Using Renal Grafts With Multiple Renal Arteries: A Putative Study on the Impact of Arterial Reconstruction Technique and Site of Implantation on Outcomes

BACKGROUND

In the present retrospective study, we analyzed the outcomes of patients transplanted with grafts with multiple renal arteries (MRAs).

PATIENTS AND METHODS

In total, 89 patients were transplanted with renal grafts with MRAs from 2003 to 2018. Demographic characteristics; type of donor; warm and cold ischemia times; arterial anastomosis technique; complications; graft function at first month, first year, and last outpatient clinic visit; and patient and graft survival were all retrospectively evaluated.

RESULTS

The mean age of the patients was 40.4 ± 13.3 years. Fifty-six patients (62.9%) were male. In total, 42 patients (47.2%) received renal grafts from living related donors. In group A (n = 24; 27%), anastomosis was performed separately to the recipient external or internal iliac arteries; in group B (n = 38; 42.7%), the secondary artery was anastomosed to the main artery in a side-to-side fashion to form a single common orifice; in group C (n = 27; 30.3%), secondary arteries were anastomosed to the main renal artery in an end-to-side fashion. Creatinine clearance at the first month was significantly lower for deceased-donor grafts compared to living-donor renal grafts (P < .05). Creatinine clearance in the first postoperative month was significantly lower in group A and creatinine clearance in the first year was significantly lower in group C (P < .05). The best survival was found for anastomosis to the internal iliac artery (P < .05).

CONCLUSION

MRAs can be safely used and the reconstruction technique does not matter if the graft kidney's arterial supply is preserved and the internal iliac artery is chosen for anastomosis.

Use of expanded-criteria donors and > 85 KDPI kidneys for pediatric kidney transplantation in the United States

Pediatric kidney transplant outcomes associated with expanded-criteria donors (ECD) and high Kidney Donor Profile Index (KDPI) kidneys are unknown. We reviewed the Scientific Registry of Transplant Recipients data from 1987-2017 to identify 96 ECD and 92 > 85 KDPI kidney recipients (<18 years). Using propensity scores, we created comparison groups of 375 non-ECD and 357 ≤ 85 KDPI recipients for comparisons with ECD and > 85 KDPI transplants, respectively. We used Cox regression for patient/graft survival and sequential Cox approach for survival benefit of ECD and > 85 KDPI transplantationvs remaining on the waitlist. After adjustment, ECD recipients were at significantly increased risk of graft failure (adjusted hazard ratio [aHR] = 1.6; P = .001) but not of mortality (aHR = 1.33; P = .15) compared with non-ECD recipients. We observed no survival benefit of ECD transplants vs remaining on the waitlist (aHR = 1.05; P = .83). We found no significant difference in graft failure (aHR = 1.27; P = .12) and mortality (aHR = 1.41; P = .13) risks between > 85 KDPI and ≤ 85 KDPI recipients. However, > 85 KDPI transplants were associated with a survival benefit vs remaining on the waitlist (aHR = 0.41; P = .01). ECD transplantation in children is associated with a high graft loss risk and no survival benefit, whereas > 85 KDPI transplantation is associated with a survival benefit for children vs remaining on the waitlist.

Reduction of Renal Preservation/Reperfusion Injury by Controlled Hyperthermia During Ex Vivo Machine Perfusion

The possible reno-protective effect of a controlled brief heat-shock treatment during isolated ex vivo machine perfusion of donor grafts prior to reperfusion should be investigated in a primary in vitro study. Porcine kidneys (n = 14) were retrieved after 20 minutes of cardiac standstill of the donor and subjected to 20 hours of static cold storage in University of Wisconsin solution. Prior to reperfusion, kidneys were subjected to 2 hours of reconditioning machine perfusion with gradual increase in perfusion temperature up to 35°C. In half of the kidneys (n = 7), a brief hyperthermic impulse (10 minutes perfusion at 42°C) was implemented in the machine perfusion period. Functional recovery of the grafts was observed upon normothermic reperfusion in vitro. Hyperthermic treatment resulted in a 50% increase of heat shock protein (HSP) 70 and HSP 27 mRNA and was accompanied by ~ 50% improvement of tubular re-absorption of sodium and glucose upon reperfusion, compared with the controls. Furthermore, renal loss of aspartate aminotransferase was significantly reduced to one-third of the controls as was urinary protein loss, evaluated by the albumin to creatinine ratio. It is concluded that ex vivo heat-shock treatment seems to be an easily implementable and promising option to enhance renal self-defense machinery against reperfusion injury after preservation that merits further investigation in preclinical models.

Ex vivo delivery of Mirococept: A dose-finding study in pig kidney after showing a low dose is insufficient to reduce delayed graft function in human kidney

The complement system plays a pivotal role in the pathogenesis of ischemia-reperfusion injury in solid organ transplantation. Mirococept is a potent membrane-localizing complement inhibitor that can be administered ex vivo to the donor kidney prior to transplantation. To evaluate the efficacy of Mirococept in reducing delayed graft function (DGF) in deceased donor renal transplantation, we undertook the efficacy of mirococept (APT070) for preventing ischaemia-reperfusion injury in the kidney allograft (EMPIRIKAL) trial (ISRCTN49958194). A dose range of 5-25 mg would be tested, starting with 10 mg in cohort 1. No significant difference between Mirococept at 10 mg and control was detected; hence the study was stopped to enable a further dose saturation study in a porcine kidney model. The optimal dose of Mirococept in pig kidney was 80 mg. This dose did not induce any additional histological damage compared to controls or after a subsequent 3 hours of normothermic machine perfusion. The amount of unbound Mirococept postperfusion was found to be within the systemic dose range considered safe in the Phase I trial. The ex vivo administration of Mirococept is a safe and feasible approach to treat DGF in deceased donor kidney transplantation. The porcine kidney study identified an optimal dose of 80 mg (equivalent to 120 mg in human kidney) that provides a basis for further clinical development.