Impact of acute kidney injury in donors on renal graft survival: a systematic review and Meta-Analysis

Cysteine as an Innovative Biomarker for Kidney Injury

BACKGROUND

Kidney transplantation is a widely used treatment for end-stage kidney disease. Nevertheless, the incidence of acute kidney injury (AKI) in deceased donors poses a potential hazard because it significantly increases the risk of delayed graft function and potentially exerts an influence on the kidney allograft outcome. It is crucial to develop a diagnostic model capable of assessing the existence and severity of AKI in renal grafts. However, no suitable kidney injury markers have been developed thus far.

METHODS

We evaluated the efficacy of the molecular probe NPO-B, which selectively responds to cysteine, as a new diagnostic tool for kidney injury. We used an in vitro model using ischemia/reperfusion injury human kidney-2 cells and an in vivo ischemia/reperfusion injury mouse model. Additionally, cysteine was investigated using urine samples from deceased donors and living donors to assess the applicability of detection techniques to humans.

RESULTS

This study confirmed that the NPO-B probe effectively identified and visualized the severity of kidney injury by detecting cysteine in both in vitro and in vivo models. We observed that the fluorescence intensity of urine samples measured using NPO-B from the deceased donors who are at a high risk of renal injury was significantly stronger than that of the living donors.

CONCLUSIONS

If implemented in clinical practice, this new diagnostic tool using NPO-B can potentially enhance the success rate of kidney transplantation by accurately determining the extent of AKI in renal grafts.

Deceased Kidney Donor Biomarkers: Relationship between Delayed Kidney Function and Graft Function Three Years after Transplantation

With an increasing number of marginal donors, additional methods for the evaluation of cadaveric kidney quality are required. This study aimed to evaluate pretransplant deceased donor serum (s) and urine (u) biomarkers, including neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), interleukin-18, and C-X-C motif chemokine 10 (CXCL10) for predicting early and late graft function. In total, 43 deceased kidney donors and 76 corresponding recipients were enrolled. Delayed graft function (DGF) occurred in 27.6% of cases. sIL-18, sKIM-1, uNGAL, and uKIM-1 were predictors of DGF. A model incorporating sIL-18, uKIM-1, and clinical factors was developed to predict DGF (AUROC 0.863). Univariate analysis showed a negative association between uKIM and graft eGFR at 6, 12, 24, and 36 months, but this was not confirmed in the multivariate analysis. In conclusion, we report a superior performance of donor biomarkers for predicting DGF and later graft function over serum creatinine. Higher levels of donor sIL-18 and uKIM in conjunction with expanded-criteria donors and longer cold ischemia times predicted DGF. With no renal tubular damage in zero-time donor biopsies, higher pretransplant urine and serum NGAL levels were associated with better allograft function one year after transplantation, and sNGAL with graft function three years after transplantation.

Renal biopsies from donors with acute kidney injury show different molecular patterns according to the post-transplant function

The utilization of kidneys from donors with acute kidney injury (AKI) is often limited by unpredictable post-transplantation outcomes. The aim of our study was to identify protein mediators implicated in either recovery or failure of these organs. Forty kidney biopsies from donors with (20) and without AKI (20) were selected and then subdivided according to the post-transplant outcome defined as a threshold of 45 ml/min for the eGFR at 1 year from transplantation. Tissue homogenates were analysed by western blot to assess how the levels of 17 pre-selected proteins varied across the four groups. Samples from AKI kidneys with a poor outcome showed a fourfold increase in the levels of PPARg and twofold reduction of STAT1 compared to the other groups (p < 0.05). On the contrary, antioxidant enzymes including TRX1 and PRX3 were increased in the AKI kidneys with a good outcome (p < 0.05). An opposite trend was observed for the detoxifying enzyme GSTp which was significantly increased in the AKI group with poor versus good outcome (p < 0.05). The importance of lipid metabolism (PPARg) and inflammatory signals (STAT1) in the function recovery of these kidneys hints to the therapeutical targeting of the involved pathways in the setting of organ reconditioning.

Past, Current, and Future Perspectives on Transplanting Acute Kidney Injury Kidneys

(1) Background: Acute kidney injury (AKI) kidneys have high non-utilization rates due to concerns regarding unfavorable outcomes. In this paper, we aimed to review the past, present, and future opinions on AKI kidneys. (2) Methods: A PubMed search was conducted for topics relevant to AKI kidney transplantation. (3) Results: Current short- and long-term data on AKI kidneys have demonstrated good outcomes including favorable graft function and survival. The role of procurement biopsies is controversial, but they have been shown to be beneficial in AKI kidneys by allowing clinicians to differentiate between reversible tubular injury and irreversible cortical necrosis. Machine perfusion has also been applied to AKI kidneys and has been shown to reduce delayed graft function (DGF). The incidence of DGF increases with AKI severity and its management can be challenging. Strategies employed to counteract this have included early initiation of dialysis after kidney transplantation, early targeting of adequate immunosuppression levels to minimize rejection risk, and establishment of outpatient dialysis. (4) Conclusions: Despite good outcomes, there continue to be barriers that impact AKI kidney utilization. Successful strategies have included use of procurement biopsies or machine perfusion and expectant management of DGF. With increasing experience, better use of AKI kidneys can result in additional opportunities to expand the donor pool.

Kidney Transplantation From Donors With Acute Kidney Injury: Are the Concerns Justified? A Systematic Review and Meta-Analysis

Renal transplantation improves quality of life and prolongs survival in patients with end-stage kidney disease, although challenges exist due to the paucity of suitable donor organs. This has been addressed by expanding the donor pool to include AKI kidneys. We aimed to establish whether transplanting such kidneys had a detrimental effect on graft outcome. The primary aim was to define early outcomes: delayed graft function (DGF) and primary non-function (PNF). The secondary aims were to define the relationship to acute rejection, allograft survival, eGFR and length of hospital stay (LOS). A systematic literature review and meta-analysis was conducted on the studies reporting the above outcomes from PubMed, Embase, and Cochrane Library databases. This analysis included 30 studies. There is a higher risk of DGF in the AKI group (OR = 2.20, p < 0.00001). There is no difference in the risk for PNF (OR 0.99, p = 0.98), acute rejection (OR 1.29, p = 0.08), eGFR decline (p = 0.05) and prolonged LOS (p = 0.11). The odds of allograft survival are similar (OR 0.95, p = 0.54). Transplanting kidneys from donors with AKI can lead to satisfactory outcomes. This is an underutilised resource which can address organ demand.

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.

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.

Combining Clinical Parameters and Acute Tubular Injury Grading Is Superior in Predicting the Prognosis of Deceased-Donor Kidney Transplantation: A 7-Year Observational Study

Background

We developed a pragmatic dichotomous grading criterion to stratify the acute tubular injury (ATI) of deceased-donor kidneys. We intended to verify the predictive value of this criterion for the prognosis of deceased-donor kidney transplantation.

Methods

The allografts with ATI were classified into severe and mild groups. Severe ATI was defined as the presence of extreme and diffuse flattening of the tubular epithelial cells, or denudement of the tubular basement membrane. The clinical delayed graft function (DGF) risk index was calculated based on a regression model for posttransplant DGF using 17 clinical parameters related to donor–recipient characteristics.

Results

A total of 140 recipients were enrolled: 18 severe and 122 mild ATI. Compared with the mild ATI group, the severe ATI group had more donors after cardiac death, higher median donor terminal serum creatinine level (dScr), and longer median cold ischemia time. Severe ATI had a higher DGF rate (55.6% vs 14.6%, p &lt; 0.001), longer DGF recovery time (49.6 vs 26.3 days, p &lt; 0.001), and a lower estimated glomerular filtration rate (eGFR) at 1 month (23.5 vs 54.0 ml/min/1.73 m2, p &lt; 0.001), 3 months (40.4 vs 59.0, p = 0.001), and 6 months after transplant (46.8 vs 60.3, p = 0.033). However, there was no significant difference in eGFR at 1 year or beyond, graft, and patient survival. The predictive value of combined dScr with ATI severity for DGF rate and DGF recovery time was superior to that of dScr alone. The predictive value of the combined DGF risk index with ATI severity for DGF was also better than that of the DGF risk index alone; however, the association of the DGF risk index with DGF recovery time was not identified. Chronic lesions including glomerulosclerosis, interstitial fibrosis, arterial intimal fibrosis, and arteriolar hyalinosis were associated with declined posttransplant 1-year eGFR.

Conclusion

Based on our pragmatic dichotomous grading criterion for ATI in a preimplantation biopsy, donor kidneys with severe ATI increased DGF risk, prolonged DGF recovery, and decreased short-term graft function but demonstrated favorable long-term graft function. Our grading method can offer additive valuable information for assessing donor kidneys with acute kidney injury and may act as an effective supplementary index of the Banff criteria.

Peritoneal Dialysis for Potential Kidney Transplant Recipients: Pride or Prejudice?

Kidney transplantation (KT) is recognized as the gold-standard of treatment for patients with end-stage renal disease. Additionally, it has been demonstrated that receiving a pre-emptive KT ensures the best recipient and graft survivals. However, due to an overwhelming discrepancy between the organs available and the patients on the transplant waiting list, the vast majority of transplant candidates require prolonged periods of dialysis before being transplanted. For many years, peritoneal dialysis (PD) and hemodialysis (HD) have been considered competitive renal replacement therapies (RRT). This dualistic vision has recently been questioned by evidence suggesting that an individualized and flexible approach may be more appropriate. In fact, tailored and cleverly planned changes between different RRT modalities, according to the patient’s needs and characteristics, are often needed in order to achieve the best results. While home HD is still under scrutiny in this particular setting, current data seems to favor the use of PD over in-center HD in patients awaiting a KT. In this specific population, the demonstrated advantages of PD are superior quality of life, longer preservation of residual renal function, lower incidence of delayed graft function, better recipient survival, and reduced cost.

Association Between Deceased Donor Acute Kidney Injury Assessed Using Baseline Serum Creatinine Back-Estimation and Graft Survival: Results From the French National CRISTAL Registry

RATIONALE & OBJECTIVE

Deceased donor acute kidney injury (AKI) frequently leads to kidney discards, but its impact on long-term graft survival in kidney transplant recipients remains unclear. We investigated the association between deceased donor AKI assessed using back-estimation of baseline serum creatinine (Scr) and graft survival.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

Adult patients represented within the French CRISTAL registry who received a single kidney allograft from brain-dead deceased donors between January 2006 and December 2017.

EXPOSURE

A back-estimated Scr baseline value was derived for an assumed glomerular filtration rate at 75mL/min/1.73m², using the MDRD Study equation. A refined classification system for donor AKI was implemented as follows: no AKI, undetermined AKI/chronic kidney disease (CKD), recovery from AKI, and ongoing AKI.

OUTCOME

Death-censored graft survival.

ANALYTICAL APPROACH

Multivariable Cox models using a robust variance estimator for paired kidneys from the same donor.

RESULTS

We classified 26,786 recipients as follows: no AKI (n=19,276); undetermined AKI/CKD (n=1,745); recovery from AKI (n=2,392); and ongoing AKI (n=3,373). We observed 4,458 kidney graft losses during a median follow-up period of 5.7 years. Compared with no AKI, ongoing AKI was associated with an increased risk of graft failure (hazard ratio [HR], 1.24 [95% CI, 1.13-1.35]). The HRs for graft failure in the undetermined AKI/CKD and recovery from AKI groups (1.22 [95% CI, 1.07-1.38] and 1.18 [95% CI, 1.06-1.31], respectively) were similar to those observed in the ongoing AKI group. The adverse effect of deceased donor AKI was no longer evident when relying either on the admission or the lowest Scr throughout the procurement procedure as baseline Scr.

LIMITATIONS

No measurement of urine output in donors.

CONCLUSIONS

Deceased donor ongoing AKI, undetermined AKI/CKD, and recovery from AKI according to back-estimated baseline Scr are associated with decreased graft survival. The definition of baseline Scr as the first value measured on admission would have led to a misclassification bias and erroneous estimates.

Impaired renal function before kidney procurement has a deleterious impact on allograft survival in very old deceased kidney donors

As the use of elderly kidney donors for transplantation is increasing with time, there is a need to understand which factors impact on their prognosis. No data exist on the impact of an impaired renal function (IRF) in such population. 116 kidney recipients from deceased kidney donors over 70 years were included from 2005 to 2015 in a single-center retrospective study. IRF before organ procurement was defined as a serum creatinine above 1.0 mg/dl or a transient episode of oligo-anuria. Mean ages for donors and recipients were respectively 74.8 ± 3.5 and 66.7 ± 8.0. Graft survival censored for death at 5 years was of 77%. Using a multivariate analysis by Cox model, the only predictor of graft loss present in the donor was IRF before organ procurement (HR 4.2 CI95[1.8–9.7]). IRF was also associated with significant lower estimated glomerular filtration rates up to 1 year post-transplantation. By contrast, KDPI score (median of 98 [96–100]), was not associated with the risk of graft failure. Then, IRF before kidney procurement may define a risk subgroup among very-old deceased kidney donors, in whom pre-implantatory biopsies, dual kidney transplantation or calcineurin inhibitor-free immunosuppressive regimen could help to improve outcomes.

Association of Admission, Nadir, and Terminal Donor Creatinine With Kidney Transplantation Outcomes

Introduction

When assessing deceased kidney donors, a key factor in organ acceptance and allocation is donor kidney function. It is unclear whether terminal, admission, or the highest of terminal and admission donor estimated glomerular filtration rate (eGFR) most predicts recipient outcomes.

Methods

We examined which measurement best predicts outcomes. Using data from the Australia and New Zealand Organ Donation and Dialysis and Transplant Registries, we included adult recipients of deceased donor kidney-only transplants over 2003 to 2019. We compared the 3 different exposure variables of admission, terminal, or highest eGFR. We created logistic regression models for delayed graft function (DGF), multilinear regression models for 6- and 12-month eGFR, and Cox proportional hazards models for graft loss, death censored graft failure and patient death.

Results

A total of 8971 transplant recipients were included. There was strong evidence of an association between terminal, admission, and highest donor eGFR and DGF and recipient eGFR at 6 and 12 months. The eGFR was a strong predictor of graft and death censored graft failure, but not patient death. Terminal was a better predictor than admission and highest eGFR particularly for more contemporaneous outcomes.

Conclusion

In assessing kidney donors, terminal eGFR were marginally better than admission and highest at predicting outcomes. Terminal eGFR should be used in risk equations to predict hard clinical endpoints.

Risk factors and outcomes of prolonged recovery from delayed graft function after deceased kidney transplantation

Objective

We aimed to evaluate the effect of prolonged recovery from DGF on outcomes, using a new definition of DGF recovery time, among deceased donor kidney transplant recipients with DGF, and to examine the risk factors for prolonged recovery.

Methods

From 2007 to 2016, 91 deceased donor kidney transplant recipients with DGF were retrospectively analyzed. DGF recovery time was defined as the time from transplantation to achieve a stable estimated glomerular filtration rate (eGFR). Recipients with a DGF recovery time greater than or equal to the median were assigned to the prolonged recovery group, while the others were assigned to the rapid recovery group.

Result

The median DGF recovery time was 27 days. Donor terminal eGFR was significantly lower in the prolonged recovery group (n = 46) compared with the rapid recovery group (n = 45) (median 24.9 vs. 65.4 ml/min/1.73m², p = 0.004). The eGFR at 1 year post-transplant in the prolonged recovery group was significantly lower than that in the rapid recovery group (50.6 ± 20.0 vs. 63.5 ± 21.4 ml/min/1.73m², p = 0.005). The risk of adverse outcomes (acute rejection, pneumonia, graft failure, and death) was significantly greater in the prolonged recovery group (hazard ratio 2.604, 95% confidence interval 1.102–6.150, p = 0.029) compared with the rapid recovery group.

Conclusion

Decreased donor terminal eGFR is a risk factor for prolonged recovery from DGF after deceased kidney transplantation. Prolonged DGF recovery time is associated with reduced graft function at 1-year post-transplant, and poor transplant outcome.

Viability assessment and utilization of declined donor kidneys with rhabdomyolysis using ex vivo normothermic perfusion without preimplantation biopsy

The role of ex vivo normothermic perfusion (EVNP) in both organ viability assessment and reconditioning is increasingly being demonstrated. We report the use of this emerging technology to facilitate the transplantation of a pair of donor kidneys with severe acute kidney injury (AKI) secondary to rhabdomyolysis. Donor creatinine was 10.18 mg/dl with protein (30 mg/dl) present in urinalysis. Both kidneys were declined by all other transplantation units and subsequently accepted by our unit. The first kidney was perfused with red cell-based perfusate at 37°C for 75 min, mean renal blood flow was 110 ml/min/100 g and produced 85 ml of urine. Having demonstrated favorable macroscopic appearance and urine output, the kidney was transplanted into a 61-year-old peritoneal dialysis dependent without complication. Given the reassuring information from the first kidney provided by EVNP, the second kidney was not perfused with EVNP and was directly implanted to a 64-year-old patient. The first kidney achieved primary function and the second functioned well after delayed graft function. Recipient eGFR have stabilized at 88.5 and 55.3, respectively (ml/min/1.73 m² ), at 2 months posttransplant.

Current concepts and advances in biomarkers of acute kidney injury

Despite advancements in standardizing the criteria for acute kidney injury (AKI), its definition remains based on changes in serum creatinine and urinary output that do not specifically represent tubular function or injury and that have significant limitations in the acute hospital setting. Much effort in nephrology has centered on identifying biomarkers of AKI to address these limitations. This review summarizes recent advances in our knowledge of biomarkers involved in pathophysiological processes during AKI and describes their potential clinical implications. Blood and urine biomarkers are released via various mechanisms during renal tubular injury. Urinary kidney injury molecule-1 (KIM-1), liver-type fatty acid binding protein (L-FABP), insulin-like growth factor-binding protein-7 (IGFBP-7), and tissue inhibitor of metalloprotease-2 (TIMP-2) are released from the proximal tubule while uromodulin (UMOD) is secreted from the loop of Henle and neutrophil gelatinase-associated lipocalin (NGAL) is released from the distal tubule. These biomarkers could therefore be used to localize specific segments of injured tubules. Biomarkers also have diverse roles in pathophysiological processes in AKI, including inflammation, repair, and fibrosis. Current evidence suggests that these biomarkers could be used to predict the transition to chronic kidney disease (CKD), decrease discard of AKI kidneys, differentiate between kidney dysfunction and injury, guide AKI management, and improve diagnosis of diseases such as acute interstitial nephritis (AIN). They could differentiate between disease phenotypes, facilitate the inclusion of a homogenous patient population in future trials of AKI, and shed light on therapeutic pathways to prevent the transition from AKI to CKD. However, a major limitation of current biomarker research in AKI is the lack of tissue correlation. The Kidney Precision Medicine Project, a large-scale national effort, is currently underway to construct a kidney tissue atlas and expand the use of biomarkers to assess nephron health. Numerous biomarkers are involved in distinct pathophysiological processes after kidney injury and have demonstrated potential to improve diagnosis and risk stratification as well as provide a prognosis for patients with AKI. Some biomarkers are ready for use in clinical trials of AKI and could guide management in various clinical settings. Further investigation of these biomarkers will provide insight that can be applied to develop novel therapeutic agents for AKI.

Meta-analyzing count events over varying durations using the piecewise Poisson model: The case for poststroke seizures

Meta-analyzing count data can be challenging when follow-up time varies across studies. Simply pooling aggregate data over time-periods would result in biased estimates, which may erroneously inform clinical decision-making. In this study, we exploit the convolution property of the Poisson distribution to develop a likelihood for observed cumulative counts over varying follow-up periods, where different Poisson distributions are used to represent the data generating processes for the latent counts in pre-defined successive intervals of follow-up. We illustrate this approach using an example of poststroke seizures, a case in which risk may change over time, and mimic its survival duration with time-varying hazard. Data were extracted from observational studies (1997-2016) reporting poststroke seizures over a maximum of 10 years of follow-up. Three clinically meaningful follow-up time intervals were considered: 0 to 7 days, 8 to 365 days, and 1 to 10 years poststroke. External validation was performed using claims data. Results suggest the incidence rate of seizures was 0.0452 (95% confidence interval: 0.0429, 0.0475), 0.0001 (0, 0.016), and 0.0647 (0.0441, 0.0941) for the three time intervals, respectively, indicating that the risk of seizures changes over time poststroke. We found that the model performed well against the incidence rate of seizures among actual retrospective cohort from claims data. The piecewise Poisson model presents a flexible way to meta-analyze count data over time and mimic survival curves. The results of the piecewise Poisson model are readily interpretable and may spur meaningful clinical action. The method may also be applied to other diseases. HIGHLIGHTS: It is challenging to perform a meta-analysis when follow-up time varies across studies. Ideally, outcomes over different time-periods should be pooled with individual patient-level data (IPD). A new model was developed to meta-analyze count data over time using aggregate-level data from previous published studies. The piecewise Poisson model could be a useful tool to estimate time-vary hazards given available data, and mimic survival curves over time which would be readily interpretable.

Urine Injury Biomarkers Are Not Associated With Kidney Transplant Failure

BACKGROUND

Kidneys transplanted from deceased donors with serum creatinine-defined acute kidney injury (AKI) have similar allograft survival as non-AKI kidneys but are discarded at a higher rate. Urine injury biomarkers are sensitive markers of structural kidney damage and may more accurately predict graft outcomes.

METHODS

In the 2010-2013 multicenter Deceased Donor Study of 2430 kidney transplant recipients from 1298 donors, we assessed the association of donor urine injury biomarkers microalbumin, neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, IL-18, and liver-type fatty acid binding protein with graft failure (GF) and death-censored GF (dcGF) using Cox proportional hazard models (median follow-up 4 y). We examined if serum creatinine-defined donor AKI modified this association to assess the relationship between subclinical donor AKI (elevated biomarkers without creatinine-defined AKI) and GF. Through chart review of a subcohort (1137 recipients), we determined associations between donor injury biomarkers and a 3-year composite outcome of GF, mortality, or estimated glomerular filtration rate ≤ 20mL/min/1.73m.

RESULTS

Risk of GF, dcGF, and 3-year composite outcome did not vary with donor injury biomarker concentrations after adjusting for donor, transplant, and recipient characteristics (adjusted hazard ratio ranged from 0.96 to 1.01 per log-2 increase in biomarker). Subclinical injury in transplanted kidneys without AKI was not associated with GF.

CONCLUSIONS

AKI measured using injury biomarkers was not associated with posttransplant graft outcomes (at median 4 y posttransplant). When assessing posttransplant graft viability, clinicians can prioritize other donor and recipient factors over donor kidney injury, measured by either serum creatinine or urine injury biomarkers.

A Review of Donor Acute Kidney Injury and Posttransplant Outcomes

Although over 90 000 people are on the kidney transplant waitlist in the United States, some kidneys that are viable for transplantation are discarded. Transplant surgeons are more likely to discard deceased donors with acute kidney injury (AKI) versus without AKI (30% versus 18%). AKI is defined using changes in creatinine from baseline. Transplant surgeons can use DonorNet data, including admission, peak, and terminal serum creatinine, and biopsy data when available to differentiate kidneys with AKI from those with chronic injury. Although chronic kidney disease is associated with reduced graft survival, an abundance of literature has demonstrated similar graft survival for deceased donors with AKI versus donors without AKI. Donors with AKI are more likely to undergo delayed graft function but have similar long-term outcomes as donors without AKI. The mechanism for similar graft survival is unclear. Some hypothesized mechanisms include (1) ischemic preconditioning; (2) posttransplant and host factors playing a greater role in long-term survival than donor factors; and (3) selection bias of transplanting only relatively healthy donor kidneys with AKI. Existing literature suggests transplanting more donor kidneys with stage 1 and 2 AKI, and cautious utilization of stage 3 AKI donors, may increase the pool of viable kidneys. Doing so can reduce the number of people who die on the waitlist by over 500 every year.

Perioperative Dexmedetomidine Improves Outcomes of Kidney Transplant

Graft function is crucial for successful kidney transplantation. Many factors may affect graft function or cause delayed graft function (DGF), which decreases the prognosis for graft survival. This study was designed to evaluate whether the perioperative use of dexmedetomidine (Dex) could improve the incidence of function of graft kidney and complications after kidney transplantation. A total of 780 patients underwent kidney transplantations, 315 received intravenous Dex infusion during surgery, and 465 did not. Data were adjusted with propensity scores and multivariate logistic regression was used. The primary outcomes are major adverse complications, including DGF and acute rejection in the early post‐transplantation phase. The secondary outcomes included length of hospital stay (LOS), infection, overall complication, graft functional status, post‐transplantation serum creatinine values, and estimated glomerular filtration rate (eGFR). Dex use significantly decreased DGF (19.37% vs. 23.66%; adjusted odds ratio, 0.744; 95% confidence interval, 0.564–0.981; P = 0.036), risk of infection, risk of acute rejection in the early post‐transplantation phase, the risk of overall complications, and LOS. However, there were no statistical differences in 90‐day graft functional status or 7‐day, 30‐day, and 90‐day eGFR. Perioperative Dex use reduced incidence of DGF, risk of infection, risk of acute rejection, overall complications, and LOS in patients who underwent kidney transplantation.

Effectiveness of serum beta-2 microglobulin as a tool for evaluating donor kidney status for transplantation

Kidney transplantations using expanded criteria donors (ECD) are being increasingly adopted, but no consensus tools are available to evaluate donor kidney status. Beta-2 microglobulin (B2MG) is a marker of kidney function, and herein, we evaluate the usefulness of assessing B2MG to evaluate donor kidney status. Fifty-seven kidney transplantations were performed from March 2017 to April 2019. Medical records were retrospectively reviewed, and relationships between clinical and laboratory variables and transplant outcomes were investigated. Thirty-eight patients received a standard criteria donor kidney and 19 patients an ECD kidney. Ten patients experienced delayed graft function (DGF), but no patient experienced primary nonfunction. Of the parameters studied, only donor renal replacement therapy (RRT) [odds ratio (OR) 24.162; p = 0.018] and donor serum B2MG (OR 22.685; p = 0.022) significantly predicted DGF. The presence of either of these two risk factors can better reflect the condition of the donor than previous classification. However, on their last follow-up creatinine and estimated glomerular filtration rate values in those with or without these risk factors were not significantly different. For an ECD with a B2MG level of <7.18 and no history of RRT, kidney transplantation can be undertaken without considering the possibility of kidney discard.

Different roles of bortezomib and ONX 0914 in acute kidney injury

Proteasome inhibitor bortezomib offers one more option for acute or chronic antibody-mediated rejection after kidney transplantation, but aggravated acute kidney injury (AKI) in some cases early after surgery using bortezomib bring new problem. Here, we evaluated the effects of bortezomib and ONX-0914 on renal tubule injury in a mouse model of ischemia-reperfusion injury. After treated with bortezomib, serum creatinine, usea nitrogen and tubular necrosis significantly increased compared with vehicle-treated mice, but decreased in ONX-0914 group mildly. Infiltration of neutrophil and macrophage were less in bortezomib and ONX-0914-treated mice than vehicle-treated group, and the same was observed on oxidative stress in the kidneys. Furthermore, the apoptosis of renal tubular epithelial cells increased in bortezomib-treated mice' kidneys compared with ONX-0914 and vehicle-treated controls. In vitro HK2 cell experiments also demonstrated the proapoptotic effect of bortezomib. The mRNA expression of several proapoptotic factors increased in kidneys of bortezomib-treated mice. In brief, bortezomib, as a proteasome inhibitor, shows a certain cytotoxicity to renal tubular epithelial cell during ischemia/reperfusion injury (IRI) through increased apoptosis. ONX-0914, as an immunoproteasome inhibitor, showed equal potency on anti-inflammation and oxidative stress relieving compared with bortezomib, while less cytotoxicity. The results render the immunoproteasome is a better target for anti-rejection and protecting kidney function in the field of organ transplantation.

T Lymphocytes in Acute Kidney Injury and Repair

Innate and adaptive immune systems participate in the pathogenesis of acute kidney injury (AKI). Considerable data from different research teams have shown the importance of T lymphocytes in the pathophysiology of AKI and, more recently, prevention and repair. T cells can generate or resolve inflammation by secreting specific cytokines and growth factors as well as interact with other immune and stromal cells to induce kidney injury or promote tissue repair. There also are emerging data on the role of T cells in the progression of AKI to chronic kidney disease and organ cross-talk in AKI. These data set the stage for immunomodulatory therapies for AKI. This review focuses on the major populations of T lymphocytes and their roles as mediators for AKI and repair.

Association of Deceased Donor Acute Kidney Injury With Recipient Graft Survival

IMPORTANCE

The shortage of deceased donor kidneys for transplants is an ongoing concern. Prior studies support transplanting kidneys from deceased donors with acute kidney injury (AKI), but those investigations have been subject to selection bias and small sample sizes. Current allocation practices of AKI kidneys in the United States are not well characterized.

OBJECTIVES

To evaluate the association of deceased donor AKI with recipient graft survival and to characterize recovery and discard practices for AKI kidneys by organ procurement organizations.

DESIGN, SETTING, AND PARTICIPANTS

Registry-based, propensity score-matched cohort study from January 1, 2010, to December 31, 2013, in the United States. The dates of analysis were March 1 to November 1, 2019. From 2010 to 2013, a total of 6832 deceased donors with AKI and 15 310 deceased donors without AKI had at least 1 kidney transplanted. This study used a 1:1, propensity score-matched analysis to match deceased donors with AKI to deceased donors without AKI and investigated outcomes in their corresponding kidney recipients.

EXPOSURE

Deceased donor AKI, defined as at least 50% or 0.3-mg/dL increase in terminal serum creatinine level from admission.

MAIN OUTCOMES AND MEASURES

Recipients were assessed for the time to death-censored graft failure and the following secondary outcomes: delayed graft function, primary nonfunction, and the time to all-cause graft failure.

RESULTS

Ninety-eight percent (6722 of 6832) of deceased donors with AKI were matched to deceased donors without AKI. The mean (SD) age of the 13 444 deceased donors was 40.4 (14.4) years, and 63% (8529 of 13 444) were male. A total of 25 323 recipients were analyzed (15 485 [61%] were male), and their mean (SD) age was 52.0 (14.7) years. Recipients were followed up for a median of 5 (interquartile range, 4-6) years. Deceased donor AKI status had no association with death-censored graft failure (hazard ratio, 1.01; 95% CI, 0.95-1.08) or all-cause graft failure (hazard ratio, 0.97; 95% CI, 0.93-1.02). The results were consistent after examining by AKI stage and adjusting for recipient and transplant characteristics. More recipients of AKI kidneys developed delayed graft function (29% vs 22%, P < .001). Few recipients (120 of 25 323 [0.5%]) developed primary nonfunction regardless of deceased donor AKI status. Recovery and transplantation of AKI kidneys varied by organ procurement organization; most (39 of 58) had high recovery and high discard of AKI kidneys.

CONCLUSIONS AND RELEVANCE

Deceased donor AKI kidneys transplanted in the study period had recipient graft survival comparable to that of non-AKI kidneys. This study's findings suggest that the transplant community should evaluate whether currently discarded AKI kidneys from donors without substantial comorbidities can be used more effectively.

Should we use kidneys from donors with acute kidney injury for renal transplantation?

The scarcity of donor organs for transplant results in long waiting times for kidney transplantation and low transplant rate worldwide. Utilization of kidneys from donors with acute kidney injury (AKI) is one of the strategies that has attracted attention recently. This article reviewed the outcomes of transplanted renal allografts from donors with acute kidney injury. Key findings about the transplant outcomes included a higher incidence of delayed graft function and primary non function, but respectable outcomes in the context of similar acute rejection rates, and graft function and graft survival. Against this background and with evidence of high mortality for patients remaining on waiting list of transplant, we advocate consideration of AKI donors for kidney transplantation.

Kidney transplantation with donors in severe acute kidney injury. Should we use these organs? Retrospective Case Series

INTRODUCTION

The number of incident and prevalent patients on dialysis has increased, as well as the number of candidates for renal transplantation in Brazil, without a proportional increase in the number of organ donors. The use of expanded kidneys, as to renal function, may be an alternative to increase the supply of organs.

OBJECTIVE

to discuss the feasibility of using expanded kidneys for renal function, which are in severe acute renal injury.

METHODS

All cases of renal transplantation of deceased donors performed at the Hospital das Clínicas de Botucatu of UNESP, from January 2010 to June 2018, totaling 732 cases were evaluated. Cases with final donor creatinine greater than 6 mg/dL were selected.

RESULTS

four patients were selected, of whom all donors were in severe acute kidney injury (AKI). These donors presented rhabdomyolysis as a probable cause of severe AKI, were young, with no comorbidities and had decreased urinary volume in the last 24 hours. The clinical evolution of all the recipients was satisfactory, with a glomerular filtration rate after transplantation ranging from 48 to 98 mL/min/1.73 m2.

CONCLUSION

this series of cases shows the possibility of using renal donors in severe AKI, provided the following are respected: donor age, rhabdomyolysis as the cause of AKI, and implantation-favorable biopsy findings. Additional studies with better designs, larger numbers of patients and longer follow-up times are needed.