Impact of cold ischemia time on renal allograft outcome using kidneys from young donors

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.

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.

The Impact of Combined Warm and Cold Ischemia Time on Post-transplant Outcomes

Background

Prolonged warm ischemia time (WIT) and cold ischemia time (CIT) are independently associated with post-transplant graft failure; their combined impact has not been previously studied. We explored the effect of combined WIT/CIT on all-cause graft failure following kidney transplantation.

Methods

The Scientific Registry of Transplant Recipients was used to identify kidney transplant recipients from January 2000 to March 2015 (after which WIT was no longer separately reported), and patients were followed until September 2017. A combined WIT/CIT variable (excluding extreme values) was separately derived for live and deceased donor recipients using cubic splines; for live donor recipients, the reference group was WIT 10 to <23 minutes and CIT >0 to <0.42 hours, and for deceased donor recipients the WIT was 10 to <25 minutes and CIT 1 to <7.75 hours. The adjusted association between combined WIT/CIT and all-cause graft failure (including death) was analyzed using Cox regression. Secondary outcomes included delayed graft function (DGF).

Results

A total of 137 125 recipients were included. For live donor recipients, patients with prolonged WIT/CIT (60 to ≤120 minutes/3.04 to ≤24 hours) had the highest adjusted hazard ratio (HR) for graft failure (HR = 1.61, 95% confidence interval [CI] = 1.14-2.29 relative to the reference group). For deceased donor recipients, a WIT/CIT of 63 to ≤120 minutes/28 to ≤48 hours was associated with an adjusted HR of 1.35 (95% CI = 1.16-1.58). Prolonged WIT/CIT was also associated with DGF for both groups although the impact was more driven by CIT.

Conclusions

Combined WIT/CIT is associated with graft loss following transplantation. Acknowledging that these are separate variables with different determinants, we emphasize the importance of capturing WIT and CIT independently. Furthermore, efforts to reduce WIT and CIT should be prioritized.

Early morning kidney transplantation: Perioperative complications

INTRODUCTION

To reduce cold ischemia time (CIT), many kidney transplants are performed in the early morning. Conducting complex surgeries in the early morning may influence the surgeon's technical capacity and rate of surgical complications (SC).

AIM

Evaluate the influence of surgery start hour (SSH) regarding duration of surgery (DS), immediate diuresis (ID), SC and acute rejection (AR); evaluate the influence of CIT regarding SC, ID, and AR.

METHODS

2855 cadaveric transplants performed between June 1980 and March 2018 were retrospectively evaluated. Regarding SSH, two groups were created: Group M (00: 00h-05.59h, n = 253) and Group D (06: 00h - 23: 59h, n = 2602). Analyzing the impact of SSH on DS, ID, SC and AR. Evaluate the relationship between CIT (< 18h, 18-30h and > 30h) on ID, SC and AR utilizing univariate and multivariate statistical analysis with SPSS.

RESULTS AND CONCLUSION

Groups M and D were comparable in all evaluated demographic variables (p > 0.05), except cold ischemia time (Group M with higher CIT, p < 0.001). Regarding univariate analysis, Surgery start hour did not influence DS (p = 0.344), and SC (p = 0.264), but related with higher ID (p = 0.028) and AR (p = 0.018). CIT related with immediate diuresis (p = 0.020) and acute rejection (p < 0.001) but did not relate with complications (p = 0.734). Regarding multivariate analysis, SSH only influenced immediate diuresis (p = 0.026) and did not influenced acute rejection (p = 0.055). CIT influenced immediate diuresis (p = 0.019) and acute rejection (p < 0.001). Surgery start hour influences Immediate diuresis. With this study, we conclude that the priority must be a short cold ischemia time.

Transplantation-Induced Ischemia-Reperfusion Injury Modulates Antigen Presentation by Donor Renal CD11c+F4/80+ Macrophages through IL-1R8 Regulation

BACKGROUND

In donor kidneys subjected to ischemia-reperfusion injury during kidney transplant, phagocytes coexpressing the F4/80 and CD11c molecules mediate proinflammatory responses and trigger adaptive immunity in transplantation through antigen presentation. After injury, however, resident renal macrophages coexpressing these surface markers acquire a proreparative phenotype, which is pivotal in controlling inflammation and fibrosis. No data are currently available regarding the effects of transplant-induced ischemia-reperfusion injury on the ability of donor-derived resident renal macrophages to act as professional antigen-presenting cells.

METHODS

We evaluated the phenotype and function of intragraft CD11c⁺F4/80⁺ renal macrophages after cold ischemia. We also assessed the modifications of donor renal macrophages after reversible ischemia-reperfusion injury in a mouse model of congeneic renal transplantation. To investigate the role played by IL-1R8, we conducted in vitro and in vivo studies comparing cells and grafts from wild-type and IL-R8-deficient donors.

RESULTS

Cold ischemia and reversible ischemia-reperfusion injury dampened antigen presentation by renal macrophages, skewed their polarization toward the M₂ phenotype, and increased surface expression of IL-1R8, diminishing activation mediated by toll-like receptor 4. Ischemic IL-1R8-deficient donor renal macrophages acquired an M₁ phenotype, effectively induced IFNγ and IL-17 responses, and failed to orchestrate tissue repair, resulting in severe graft fibrosis and aberrant humoral immune responses.

CONCLUSIONS

IL-1R8 is a key regulator of donor renal macrophage functions after ischemia-reperfusion injury, crucial to guiding the phenotype and antigen-presenting role of these cells. It may therefore represent an intriguing pathway to explore with respect to modulating responses against autoantigens and alloantigens after kidney transplant.

Anti-donor MHC Class II Alloantibody Induces Glomerular Injury in Mouse Renal Allografts Subjected to Prolonged Cold Ischemia

BACKGROUND

The mechanisms underlying the effects of prolonged cold-ischemia storage on kidney allografts are poorly understood.

METHODS

To investigate effects of cold ischemia on donor-reactive immune responses and graft pathology, we used a mouse kidney transplantation model that subjected MHC-mismatched BALB/c kidney allografts to cold-ischemia storage for 0.5 or 6 hours before transplant into C57BL/6 mice.

RESULTS

At day 14 post-transplant, recipients of allografts subjected to 6 versus 0.5 hours of cold-ischemia storage had increased levels of anti-MHC class II (but not class I) donor-specific antibodies, increased donor-reactive T cells, and a significantly higher proportion of transplant glomeruli infiltrated with macrophages. By day 60 post-transplant, allografts with a 6 hour cold-ischemia time developed extensive glomerular injury compared with moderate pathology in allografts with 0.5 hour of cold-ischemia time. Pathology was associated with increased serum levels of anti-class 2 but not anti-class 1 donor-specific antibodies. Recipient B cell depletion abrogated early macrophage recruitment, suggesting augmented donor-specific antibodies, rather than T cells, increase glomerular pathology after prolonged cold ischemia. Lymphocyte sequestration with sphingosine-1-phosphate receptor 1 antagonist FTY720 specifically inhibited anti-MHC class II antibody production and abrogated macrophage infiltration into glomeruli. Adoptive transfer of sera containing anti-donor MHC class II antibodies or mAbs against donor MHC class II restored early glomerular macrophage infiltration in FTY720-treated recipients.

CONCLUSIONS

Post-transplant inflammation augments generation of donor-specific antibodies against MHC class II antigens. Resulting MHC class II-reactive donor-specific antibodies are essential mediators of kidney allograft glomerular injury caused by prolonged cold ischemia.

Time of Cold Ischemia and Delayed Graft Function in a Cohort of Renal Transplant Patients in a Reference Center

There are many factors involved in the delayed graft function of a renal graft, with prolonged cold ischemia time being one of the most relevant. The aim of this study is to evaluate the relationship between the time of cold ischemia and the delayed graft function, and acute rejection and graft loss at 1 year of follow-up. A retrospective cohort of 347 renal transplant patients were evaluated during the years 2009-2013. The incidence of delayed graft function was 18.4% (n = 65). The cold ischemia time was an independent risk factor for delayed graft function (odds ratio [OR] 1.10, 95% confidence interval [CI] 1.04-1.16). By grouping the time of cold ischemia by intervals, the risk of delayed graft function was greater in the 12-18 hours group (OR 2.06, 95% CI 1.02-4.15) and in the >18 hours group (OR 3.38, 95% CI 1.57-7.27). The risk of acute rejection did not increase with longer cold ischemia (p = 0.69), and cold ischemia time was not a risk factor for renal graft loss at 1-year follow-up (hazard ratio 0.97, 95% CI 0.88-1.06). In conclusion the time of cold ischemia (>12 hours) in renal transplant recipients of optimal deceased donors increases the risk of delayed graft function; however, this does not negatively impact the results in acute rejection or graft loss in the first year of the transplant.

Molecular mechanisms and cell signaling of 20-hydroxyeicosatetraenoic acid in vascular pathophysiology

Cytochrome P450s enzymes catalyze the metabolism of arachidonic acid to epoxyeicosatrienoic acids (EETs), dihydroxyeicosatetraenoic acid and hydroxyeicosatetraeonic acid (HETEs). 20-HETE is a vasoconstrictor that depolarizes vascular smooth muscle cells by blocking K+ channels. EETs serve as endothelial derived hyperpolarizing factors. Inhibition of the formation of 20-HETE impairs the myogenic response and autoregulation of renal and cerebral blood flow. Changes in the formation of EETs and 20-HETE have been reported in hypertension and drugs that target these pathways alter blood pressure in animal models. Sequence variants in CYP4A11 and CYP4F2 that produce 20-HETE, UDP-glucuronosyl transferase involved in the biotransformation of 20-HETE and soluble epoxide hydrolase that inactivates EETs are associated with hypertension in human studies. 20-HETE contributes to the regulation of vascular hypertrophy, restenosis, angiogenesis and inflammation. It also promotes endothelial dysfunction and contributes to cerebral vasospasm and ischemia-reperfusion injury in the brain, kidney and heart. This review will focus on the role of 20-HETE in vascular dysfunction, inflammation, ischemic and hemorrhagic stroke and cardiac and renal ischemia reperfusion injury.

Nighttime procedures are not associated with adverse outcomes in kidney transplantation

Surgeries performed during the night are associated with higher complication rates. The aim of this study was to determine the impact of nighttime surgery on the outcome after kidney transplantation. In all, 873 deceased donor kidney transplants were retrospectively analyzed and grouped according to the time of surgery: daytime (8 AM to 8 PM, n = 610) versus nighttime (8 PM to 8 AM, n = 263). Statistical analysis compared patient/graft survival, rate of delayed graft function (DGF), acute rejection rate, and surgical complications. One and 5-year patient and graft survival did not differ between daytime and nighttime transplants. DGF occurred in 31.1% of daytime compared to 37.6% of nighttime procedures (P = 0.06). Acute allograft rejection was observed in 22.6% of daytime compared to 18.3% in nighttime graft recipients (P = 0.15). Nighttime procedures were associated with 22.4% complications compared to 22.1% in daytime procedures (P = 0.92). Most importantly, if transplantations were postponed until the next morning, cold ischemia time (CIT) would have increased from 16.6 h to 24.6 h (P < 0.0001) which would have resulted in decreased long-term survival (P < 0.02). Nighttime kidney transplants are neither associated with a higher surgical complication rate nor worse 5-year outcomes than daytime procedures, thus are justified to keep CIT short.

Influence of prolonged cold ischemia in renal transplantation

AIM

To determine to what extent current cold ischemia times (CITs) affect the results of renal transplantation in the Netherlands.

METHODS

Retrospective survey of the Dutch Organ Transplant Registry concerning transplants from deceased donors between 1990 and 2007.

RESULTS

A total of 6322 recipients were identified, of whom 5306 received a kidney from deceased heartbeating (HBD) and 1016 from donors after cardiac death (DCD). Mean CIT was 24.0 ± 7.9 h in HBD and 21.6 ± 6.7 h in DCD. The percentage delayed graft function (DGF) was 12.3 and 50.4, respectively (p < 0.001). Primary non-function (PNF) occurred in, respectively, 1.7% and 5.0% (p < 0.001). Serum creatinine after three months was 166 μM in HBD and 213 μM in DCD (p < 0.001). Five-yr graft survival was 79.5% and 78.3%, respectively (p = ns). In multivariate analysis, CIT proved to be an independent risk factor for DGF and PNF. Shorter CIT was associated with better graft survival in both groups with a hazard ratio of 1.024 (1.011-1.037, 95% CI)/h. CIT <20 h was associated with a graft survival benefit of 3% after five yr in HBD and CIT of <16 h with a benefit of 10% in DCD.

CONCLUSIONS

Longer CITs are associated with the occurrence of DGF, PNF and decreased graft survival in the Netherlands.

Improvement in late renal allograft survival between 1990 and 2002 in Spain: results from a multicentre case-control study

Epidemiological studies have failed to show an improvement in graft survival beyond 1 year after kidney transplantation possibly because of an increased number of expanded donors and older recipients. Thus, we performed a case-control study matching patients transplanted in different eras by donor and recipient characteristics. We considered renal transplant recipients included in the database of the Spanish Chronic Allograft Dysfunction Study Group in 1990, 1994, 1998 and 2002 (n = 4842). We matched patients from these cohorts considering the following variables: donor and recipient age, cause of donor death, hepatitis C virus, panel reactive antibodies and re-transplantation. We identified a total of 896 patients distributed in four cohorts of 224 matched patients. Between 1990 and 2002, the use of cyclosporin decreased (96%, 94%, 80% and 23% respectively, P = 0.001), while the use of tacrolimus increased (0%, 1%, 15% and 63% respectively, P = 0.001) and the prevalence of acute rejection decreased (46%, 37.9%, 20.6% and 15.8% respectively, P < 0.001). One-year serum creatinine was 1.63 +/- 0.66, 1.64 +/- 0.70, 1.44 +/- 0.52 and 1.38 +/- 0.75 respectively, P = 0.001. Graft survival beyond the first year between 1990 and 2002 significantly improved while patient survival did not. Transplant outcome has improved between 1990 and 2002 when donors and recipients of similar characteristics are compared.

Is it possible to predict the early post-transplant allograft function using 20-HETE measurements? A preliminary report

20-HydroxyEicosaTetraEnoic (20-HETE) acid is an arachidonic acid metabolite that is generated via cytochrome P450 enzymes, and according to the findings from recent studies, may be involved in the pathogenesis of ischemia-reperfusion injury. The aim of this study was to: examine the dynamics of 20-HETE changes during the first 5 min of allograft reperfusion, and analyze whether the observed changes are associated with post-transplant graft function. Sixty-nine renal transplant recipients were divided, according to their outcome, into early, slow and delayed graft function (EGF, SGF, DGF) group. Blood samples were collected directly before and during the first 5 min of allograft reperfusion. 20-HETE concentrations were measured using ELISA. The results demonstrated significant differences in the concentrations and in the dynamics of 20-HETE changes between patients with immediate graft function, and individuals with allograft activation problems. The sensitivity, specificity, positive and negative predictive value of 20-HETEDelta(5-0) parameter in discriminating EGF and SGF from DGF were 69%, 54%, 74% and 48% respectively. Therefore, our results demonstrated that the dynamics of 20-HETE changes, which occurs during early phase of allograft reperfusion, is associated with early post-transplant graft function and also highlighted 20-HETE as a novel clinical marker of post-transplant allograft function.