Is prolonged cold ischemia a contraindication to using kidneys from acute kidney injury donors?

The Kidney Not Taken: Single-Kidney Use in Deceased Donors

BACKGROUND

The nonuse rate for kidneys recovered from deceased donors is increasing, rising to 27% in 2023. In 10% of these cases, 1 kidney is transplanted but the mate kidney is not.

STUDY DESIGN

We conducted a retrospective, single-center cohort study from December 2001 to May 2023 comparing single kidneys transplanted at our center (where the contralateral kidney was not used) to kidneys where both were transplanted separately, at least 1 of which was at our center.

RESULTS

We performed 395 single deceased-donor kidney transplants in which the mate kidney was not transplanted. Primary reasons for mate kidney nonuse were as follows: no recipient located or list exhausted (33.4%), kidney trauma or injury or anatomic abnormalities (18.7%), biopsy findings (16.7%), and poor renal function (13.7%). Mean donor and recipient ages were 51.5 ± 14.2 and 60 ± 12.6 years, respectively. Mean kidney donor profile index was 73% ± 22%, and 104 donors (26.3%) had kidney donor profile index >85%. Mean cold ischemia was 25.6 ± 7.4 hours, and 280 kidneys (70.7%) were imported. Compared with 2,303 concurrent control transplants performed at our center, primary nonfunction or thrombosis (5.1% single vs 2.8% control) and delayed graft function (35.4% single vs 30.1% control) were greater with single-kidney use (both p < 0.05). Median patient and death-censored graft survival were shorter in the single group (11.6 vs 13.5 years, p = 0.03 and 11.6 vs 19 years, p = 0.003), although the former was at least double median survival on the waiting list. In patients with functioning grafts in the single-kidney group, 1-year mean serum creatinine was 1.77 ± 0.8 mg/dL and estimated glomerular filtration rate was 44.8 ± 20 mL/min/1.73 m 2 .

CONCLUSIONS

These findings suggest that many mate kidneys are being inappropriately rejected, given the acceptable outcomes that can be achieved by transplanting the single kidney in appropriately selected recipients.

Mitochondria Transplantation Mitigates Damage in an In Vitro Model of Renal Tubular Injury and in an Ex Vivo Model of DCD Renal Transplantation

OBJECTIVES

To test whether mitochondrial transplantation (MITO) mitigates damage in 2 models of acute kidney injury (AKI).

BACKGROUND

MITO is a process where exogenous isolated mitochondria are taken up by cells. As virtually any morbid clinical condition is characterized by mitochondrial distress, MITO may find a role as a treatment modality in numerous clinical scenarios including AKI.

METHODS

For the in vitro experiments, human proximal tubular cells were damaged and then treated with mitochondria or placebo. For the ex vivo experiments, we developed a non-survival ex vivo porcine model mimicking the donation after cardiac death renal transplantation scenario. One kidney was treated with mitochondria, although the mate organ received placebo, before being perfused at room temperature for 24 hours. Perfusate samples were collected at different time points and analyzed with Raman spectroscopy. Biopsies taken at baseline and 24 hours were analyzed with standard pathology, immunohistochemistry, and RNA sequencing analysis.

RESULTS

In vitro, cells treated with MITO showed higher proliferative capacity and adenosine 5'-triphosphate production, preservation of physiological polarization of the organelles and lower toxicity and reactive oxygen species production. Ex vivo, kidneys treated with MITO shed fewer molecular species, indicating stability. In these kidneys, pathology showed less damage whereas RNAseq analysis showed modulation of genes and pathways most consistent with mitochondrial biogenesis and energy metabolism and downregulation of genes involved in neutrophil recruitment, including IL1A, CXCL8, and PIK3R1.

CONCLUSIONS

MITO mitigates AKI both in vitro and ex vivo.

Single center experience and literature review of kidney transplantation from non-ideal donors with acute kidney injury: Risk and reward

INTRODUCTION

There is limited experience transplanting kidneys from either expanded criteria donors (ECD) or donation after circulatory death (DCD) deceased donors with terminal acute kidney injury (AKI).

METHODS

AKI kidneys were defined by a donor terminal serum creatinine level >2.0 mg/dL whereas non-ideal deceased donor (NIDD) kidneys were defined as AKI/DCD or AKI/ECDs.

RESULTS

From February 2007 to March 2023, we transplanted 266 single AKI donor kidneys including 29 from ECDs, 29 from DCDs (n = 58 NIDDs), and 208 from brain-dead standard criteria donors (SCDs). Mean donor age (43.7 NIDD vs. 33.5 years SCD), KDPI (66% NIDD vs. 45% SCD), and recipient age (57 NIDD vs. 51 years SCD) were higher in the NIDD group (all p < .01). Mean waiting times (17.8 NIDD vs. 24.2 months SCD) and dialysis duration (34 NIDD vs. 47 months SCD) were shorter in the NIDD group (p < .05). Delayed graft function (DGF, 48%) and 1-year graft survival (92.7% NIDD vs. 95.9% SCD) was similar in both groups. Five-year patient and kidney graft survival rates were 82.1% versus 89.9% and 82.1% versus 75.2% (both p = NS) in the NIDD versus SCD groups, respectively.

CONCLUSIONS

The use of kidneys from AKI donors can be safely liberalized to include selected ECD and DCD donors.

Long-term outcomes of kidney transplantation from deceased donors with terminal acute kidney injury: Single center experience and literature review

INTRODUCTION

Long-term outcomes of kidney transplantation from deceased donors (DDKTs) with terminal acute kidney injury (AKI) are not well defined.

METHODS

Single center retrospective review of DDKTs from 1/31/07-12/31/19. AKI kidneys were defined by a doubling of the donor's admission serum creatinine (SCr) level AND a terminal SCr ≥2.0 mg/dl.

RESULTS

A total of 188 AKI DDKTs were performed, including 154 from brain-dead standard criteria donors (SCD). Mean donor age was 36 years and mean Kidney Donor Profile Index was 50%; mean admission and terminal SCr levels were 1.3 and 3.1 mg/dl, respectively. With a mean follow-up of 94 months (median 89 months), overall patient (both 71.3%) and graft survival (54% AKI vs. 57% non-AKI) rates were comparable to concurrent DDKTs from brain-dead non-AKI SCDs (n = 769). Delayed graft function (DGF) was higher in AKI kidney recipients (47% vs. 20% non-AKI DDKTs, p < .0001). DGF was associated with lower graft survival in recipients of both AKI and non-AKI SCD kidneys but the impact was earlier and more pronounced in non-AKI recipients.

CONCLUSIONS

Despite having more than twice the incidence of DGF, kidneys from deceased donors with terminal AKI have long-term outcomes comparable to non-AKI SCD kidneys and represent a safe and effective method to expand the donor pool.

Complement Blockade in Recipients Prevents Delayed Graft Function and Delays Antibody-mediated Rejection in a Nonhuman Primate Model of Kidney Transplantation

BACKGROUND

Complement activation in kidney transplantation is implicated in the pathogenesis of delayed graft function (DGF). This study evaluated the therapeutic efficacy of high-dose recombinant human C1 esterase inhibitor (rhC1INH) to prevent DGF in a nonhuman primate model of kidney transplantation after brain death and prolonged cold ischemia.

METHODS

Brain death donors underwent 20 h of conventional management. Procured kidneys were stored on ice for 44-48 h, then transplanted into ABO-compatible major histocompatibility complex-mismatched recipients. Recipients were treated with vehicle (n = 5) or rhC1INH 500 U/kg plus heparin 40 U/kg (n = 8) before reperfusion, 12 h, and 24 h posttransplant. Recipients were followed up for 120 d.

RESULTS

Of vehicle-treated recipients, 80% (4 of 5) developed DGF versus 12.5% (1 of 8) rhC1INH-treated recipients (P = 0.015). rhC1INH-treated recipients had faster creatinine recovery, superior urinary output, and reduced urinary neutrophil gelatinase-associated lipocalin and tissue inhibitor of metalloproteinases 2-insulin-like growth factor-binding protein 7 throughout the first week, indicating reduced allograft injury. Treated recipients presented lower postreperfusion plasma interleukin (IL)-6, IL-8, tumor necrosis factor-alpha, and IL-18, lower day 4 monocyte chemoattractant protein 1, and trended toward lower C5. Treated recipients exhibited less C3b/C5b-9 deposition on day 7 biopsies. rhC1INH-treated animals also trended toward prolonged mediated rejection-free survival.

CONCLUSIONS

Our results recommend high-dose C1INH complement blockade in transplant recipients as an effective strategy to reduce kidney injury and inflammation, prevent DGF, delay antibody-mediated rejection development, and improve transplant outcomes.

Molecular Pathways Underlying Adaptive Repair of the Injured Kidney: Novel Donation After Cardiac Death and Acute Kidney Injury Platforms

OBJECTIVE

To test the hypothesis that gene expression profiling in peripheral blood from patients who have undergone kidney transplantation (KT) will provide mechanistic insights regarding graft repair and regeneration.

BACKGROUND

Renal grafts obtained from living donors (LD) typically function immediately, whereas organs from donation after cardiac death (DCD) or acute kidney injury (AKI) donors may experience delayed function with eventual recovery. Thus, recipients of LD, DCD, and AKI kidneys were studied to provide a more complete understanding of the molecular basis for renal recovery.

METHODS

Peripheral blood was collected from LD and DCD/AKI recipients before transplant and throughout the first 30 days thereafter. Total RNA was isolated and assayed on whole genome microarrays.

RESULTS

Comparison of longitudinal gene expression between LD and AKI/DCD revealed 2 clusters, representing 141 differentially expressed transcripts. A subset of 11 transcripts was found to be differentially expressed in AKI/DCD versus LD. In all recipients, the most robust gene expression changes were observed in the first day after transplantation. After day 1, gene expression profiles differed depending upon the source of the graft. In patients receiving LD grafts, the expression of most genes did not remain markedly elevated beyond the first day post-KT. In the AKI/DCD groups, elevations in gene expression were maintained for at least 5 days post-KT. In all recipients, the pattern of coordinate gene overexpression subsided by 28 to 30 days.

CONCLUSIONS

Gene expression in peripheral blood of AKI/DCD recipients offers a novel platform to understand the potential mechanisms and timing of kidney repair and regeneration after transplantation.

Impact of Cold Ischemia Time in Clinical Outcomes in Deceased Donor Renal Transplant

BACKGROUND

Renal transplants (RTs) from deceased donors have increased in Mexico because of the high need of people with terminal kidney damage. The objective of this study is to determine the impact of cold ischemia time (CIT) on clinical outcomes in the deceased donor kidney transplant.

METHODS

A retrospective, observational study of deceased donor RTs performed from 2013 to 2017 in the RT unit of the CMN Siglo XXI was completed. Data were collected from 202 patient records in this period; 7 clinical outcomes were determined, and logistic regression analysis was performed with CIT and extended criteria. The statistical package SPSS version 25 was used.

RESULTS

No risk was observed for clinical outcomes with a CIT of 1080 minutes, risk of delayed function and medical complications was observed with a CIT of 1260 minutes, and risk of surgical complications was observed with a CIT of 1309 minutes. There was a correlation of 0.556 between the Maryland classification score and post-transplant medical complications. The extended criteria are related to risk for death with an odds ratio of 6.91 (95% CI, 2.27-21.01; P = .001) CONCLUSIONS: CIT continues to be an extremely important factor in renal graft survival and post-transplant clinical conditions. The extended criteria represent a considerable risk of death.

Marginal kidney transplantation: the road less traveled

PURPOSE OF REVIEW

Kidney transplantation indisputably confers a significant survival advantage and a better quality of life compared with dialysis, however, because of the increasing demand for kidney transplantation many patients continue to wait prolonged periods for kidney transplantation. The first step to alleviate the shortage is to reduce the discard rate by utilizing more marginal kidneys. This review studied the recent literature on marginal kidney transplantation.

RECENT FINDINGS

More than 60% of high-KDPI kidneys are discarded. Despite the increase in posttransplant costs, use of high KDPI transplants suggests a gain in survival years, thus making marginal kidney transplant cost effective. Furthermore, recent evidence suggests that marginal kidney transplantation shows a survival benefit compared with remaining in the waitlist and minimizes the kidney discard rate.

SUMMARY

Transplantation with marginal kidneys provides a survival benefit over dialysis or waiting for a low-KDPI kidney. As a result, clinicians should strongly consider transplantation of marginal kidneys as opposed to waiting for a better offer.

Factors of Acute Kidney Injury Donors Affecting Outcomes of Kidney Transplantation From Deceased Donors

BACKGROUND

This study aimed to investigate the outcomes of kidney transplantation (KT) from deceased acute kidney injury (AKI) donors and analyzed the factors affecting these outcomes.

METHODS

All patients who underwent KT from deceased donors at our institution from 1998 to 2016 were retrospectively reviewed. Recipients were divided into the AKI and non-AKI donor groups. We analyzed delayed graft function (DGF), serum creatinine levels at 1 month and 1 year after KT, cold ischemia time, donors' initial and terminal serum creatinine levels, Kidney Donor Profile Index, and patient and graft survival in each group.

RESULTS

Of 181 recipients, 30 received kidneys from 21 AKI donors, whereas the remaining 151 received kidneys from donors without AKI. DGF more frequently developed in the AKI donor group than in the non-AKI donor group (40% vs 7.28%; P = .001). Allograft functions at 1 month and 1 year after KT did not differ between the AKI and non-AKI donor groups (1 month: P = .469; 1 year: P = .691). Factors affecting DGF were recipient weight and donor AKI. Recipient factors affecting graft function at 1 year were recipient height, length of hospital stay, serum creatinine levels at 1 month and 6 months, and biopsy-proven acute rejection. Older donor age was the only donor factor that affected graft function at 1 year.

CONCLUSION

KT from deceased AKI donors showed a higher DGF rate but favorable patient and graft survival and graft functions. Donor AKI and recipient weight affected DGF, and only older donor age affected graft function at 1 year.

Perioperative-, Recipient-, and Donor-Related Factors Affecting Delayed Graft Function in Kidney Transplantation

OBJECTIVES

Delayed graft function is a frequent complication in deceased-donor kidney transplant, with an incidence ranging from 10% to 50% among different centers; it is also associated with lower graft survival. In this study, we aimed to identify risk factors for delayed graft function, particularly those associated with perioperative management (including cold ischemia time) and nonmodifiable recipient- and donor-related factors. The effects of delayed graft function on graft and patient outcomes were also evaluated.

MATERIALS AND METHODS

Our retrospective analyses included 125 adult patients who underwent deceased-donor kidney transplant. Delayed graft function was diagnosed if at least 1 dialysis treatment was required during the first week posttransplant according to Perico's definition.

RESULTS

Prevalence of delayed graft function was 30.4% (n = 38). Cold ischemia time was significantly prolonged in patients with delayed graft function compared with those without it. Multivariate regression showed that cold ischemia time was the only predictor of delayed graft function. A cutoff of 9 hours and 12 minutes was found as a limit beyond which delayed graft function occurred (sensitivity = 90%; specificity = 29%; area under the curve = 0.68). Greater donor and recipient age and longer pretransplant dialysis time in recipients were associated with occurrence of delayed graft function. In patients with delayed graft function, hospital stay duration was significantly greater and 1-year graft survival was significantly lower.

CONCLUSIONS

Efforts should be focused on limiting cold ischemia time and associated injury to reduce occurrence of delayed graft function and consequently improve long-term graft survival in kidney transplant recipients. Optimization of posttransplant renal function with the help of new technologies, such as pulsatile perfusion, could be crucial for minimization of cold ischemia time.