Economic impact of delayed graft function and suboptimal kidneys

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.

Predictive Models for the Functional Recovery of Transplanted Kidney

BACKGROUND

Renal transplantation is the gold standard treatment for end-stage renal disease, however, in 20% of cases, the graft develops a delayed graft function (DGF) that is associated with both early and late worsening of the outcome. The aim of this study was to examine and validate in a population of transplanted patients the appropriateness of the predictive score systems of DGF available to identify patients who might take advantage of a tailored immunosuppressive therapy.

MATERIALS AND METHODS

We conducted a systematic review of the literature to identify articles concerning scoring systems predicting DGF to identify those applicable to the study population and subsequently comparing their appropriateness for defining the most accurate one.

RESULTS

From an analysis of the scientific literature, we found 7 scoring systems predicting DGF. Of these, 3 can be calculated for the study population. We enrolled 247 renal transplants in the study. DGF was recorded in 41 cases (15.95%). The Irish score recognized 25 of 41 cases (60.98%), the Jeldres score 41 of 41 cases (100%), and the Chapal score only 7 of 41 (17.07%). Although the Irish score did not identify all cases of DGF, the analysis of data revealed that it is the most accurate, with area under the receiver operating characteristic almost overlapping.

CONCLUSIONS

The study resulted in some interesting and promising conclusions about the predictability of DGF, defining the Irish score as the most reliable. This result can be considered the fundamental requirement to develop a custom therapeutic algorithm to be applied to all recipients with higher probability of developing DGF.

Plasma Macrophage Migration Inhibitory Factor Predicts Graft Function Following Kidney Transplantation: A Prospective Cohort Study

Background: Delayed graft function (DGF) is a common complication after kidney transplantation (KT) with a poor clinical outcome. There are no accurate biomarkers for the early prediction of DGF. Macrophage migration inhibitory factor (MIF) release during surgery plays a key role in protecting the kidney, and may be a potential biomarker for predicting post-transplant renal allograft recovery.

Methods: Recipients who underwent KT between July 2020 and December 2020 were enrolled in the study. Plasma MIF levels were tested in recipients at different time points, and the correlation between plasma MIF and DGF in recipients was evaluated. This study was registered in the Chinese Clinical Trial Registry (ChiCTR2000035596).

Results: Intraoperative MIF levels were different between immediate, slowed, and delayed graft function groups (7.26 vs. 6.49 and 5.59, P < 0.001). Plasma MIF was an independent protective factor of DGF (odds ratio = 0.447, 95% confidence interval [CI] 0.264–0.754, P = 0.003). Combining plasma MIF level and donor terminal serum creatinine provided the best predictive power for DGF (0.872; 95%CI 0.795–0.949). Furthermore, plasma MIF was significantly associated with allograft function at 1-month post-transplant (R² = 0.42, P < 0.001).

Conclusion: Intraoperative MIF, as an independent protective factor for DGF, has excellent diagnostic performance for predicting DGF and is worthy of further exploration.

Personalized prediction of delayed graft function for recipients of deceased donor kidney transplants with machine learning

Machine learning (ML) has shown its potential to improve patient care over the last decade. In organ transplantation, delayed graft function (DGF) remains a major concern in deceased donor kidney transplantation (DDKT). To this end, we harnessed ML to build personalized prognostic models to predict DGF. Registry data were obtained on adult DDKT recipients for model development (n = 55,044) and validation (n = 6176). Incidence rates of DGF were 25.1% and 26.3% for the development and validation sets, respectively. Twenty-six predictors were identified via recursive feature elimination with random forest. Five widely-used ML algorithms-logistic regression (LR), elastic net, random forest, artificial neural network (ANN), and extreme gradient boosting (XGB) were trained and compared with a baseline LR model fitted with previously identified risk factors. The new ML models, particularly ANN with the area under the receiver operating characteristic curve (ROC-AUC) of 0.732 and XGB with ROC-AUC of 0.735, exhibited superior performance to the baseline model (ROC-AUC = 0.705). This study demonstrates the use of ML as a viable strategy to enable personalized risk quantification for medical applications. If successfully implemented, our models may aid in both risk quantification for DGF prevention clinical trials and personalized clinical decision making.

Cold Pulsatile Machine Perfusion Versus Static Cold Storage for Kidneys Donated After Circulatory Death: A Multicenter Randomized Controlled Trial

BACKGROUND

The benefits of cold pulsatile machine perfusion (MP) for the storage and transportation of kidneys donated after circulatory death are disputed. We conducted a UK-based multicenter, randomized controlled trial to compare outcomes of kidneys stored with MP versus static cold storage (CS).

METHODS

Fifty-one pairs of kidneys donated after circulatory death were randomly allocated to receive static CS or cold pulsatile MP. The primary endpoint, delayed graft function, was analyzed by "intention-to-treat" evaluation.

RESULTS

There was no difference in the incidence of delayed graft function between CS and MP (32/51 (62.8%) and 30/51 (58.8%) P = 0.69, respectively), although the trial stopped early due to difficulty with recruitment. There was no difference in the incidence of acute rejection, or in graft or patient survival between the CS and MP groups. Median estimated glomerular filtration rate at 3 months following transplantation was significantly lower in the CS group compared with MP (CS 34 mL/min IQR 26-44 vs MP 45 mL/min IQR 36-60, P = 0.006), although there was no significant difference in estimated glomerular filtration rate between CS and MP at 12 months posttransplant.

CONCLUSIONS

This study is underpowered, which limits definitive conclusions about the use of MP, as an alternative to static CS. It did not demonstrate that the use of MP reduces the incidence of delayed graft function in donation after circulatory death kidney transplantation.

Donor Plasma Mitochondrial DNA Is Correlated with Posttransplant Renal Allograft Function

BACKGROUND

The lack of accurate biomarkers makes it difficult to determine whether organs are suitable for transplantation. Mitochondrial DNA (mtDNA) correlates with tissue damage and kidney disease, making it a potential biomarker in organ evaluation.

METHODS

Donors who had experienced cardiac death and successfully donated their kidneys between January 2015 and May 2017 were included this study. We detected the level of mtDNA in the plasma of the donor using quantitative real-time polymerase chain reaction and then statistically analyzed the relationship between the level of mtDNA and the delayed graft function (DGF) of the recipient.

RESULTS

The incidence of DGF or slowed graft function (SGF) increased by 4 times (68% versus 16%, P < 0.001) when the donor mtDNA (dmtDNA) level was >0.114. When dmtDNA levels were >0.243, DGF and primary nonfunction were approximately 100% and 44%, respectively. Moreover, dmtDNA was an independent risk factor for slowed graft function and DGF. A prediction model for DGF based on dmtDNA achieved an area under the receiver operating characteristic curve for a prediction score as high as 0.930 (95% confidence interval 0.856-1.000), and the validation cohort results showed that the sensitivity and specificity of the model were 100% and 78%, respectively. dmtDNA levels were correlated with 6-month allograft function (R=0.332, P < 0.001) and 1-year graft survival (79% versus 99%, P < 0.001).

CONCLUSIONS

We conclusively demonstrated that plasma dmtDNA was an independent risk factor for DGF, which is valuable in organ evaluation. dmtDNA is a possible first predictive marker for primary nonfunction and worth further evaluation.

Outcomes From Right Versus Left Deceased-Donor Kidney Transplants: A US National Cohort Study

RATIONALE & OBJECTIVE

There may be important transplant-related differences between right and left kidneys, including logistical/surgical considerations about vessel length for the right compared to the left kidney from the same donor. Because US centers choose between the right and left kidney when their recipient is ranked higher on a "match-run," we sought to determine whether deceased-donor right kidneys have had worse posttransplantation outcomes than left kidneys.

STUDY DESIGN

Paired Organ Procurement and Transplantation Network analysis.

SETTING & PARTICIPANTS

Deceased-donor kidney pairs transplanted during 1990 to 2016.

EXPOSURE

Right versus left kidney controlling for other significant factors.

OUTCOMES

Delayed graft function (DGF), all-cause and death-censored graft failure, and mortality.

ANALYTICAL APPROACH

Multivariable conditional logistic regression for DGF; proportional hazards models (conditional on same donor) for failure/mortality with right kidneys (operationalized as 6-month time-varying coefficients) adjusting for DGF and other confounders.

RESULTS

87,112 recipient pairs shared the following donor characteristics: mean age of 41 ± 14 years, 60% males, and 11% with cardiac death. Recipient characteristics were numerically similar by donor kidney side but with some statistical differences given the sample size. Right kidneys had slightly longer cold ischemia time. DGF occurred more often for right kidneys (28% vs 25.8%; P < 0.001; adjusted OR, 1.15 [95% CI, 1.12-1.17]). The adjusted hazard ratio (aHR) for all-cause graft failure with right kidneys within 6 months was 1.07 (95% CI, 1.03-1.11), and was 0.99 (95% CI, 0.97-1.01) thereafter. The aHRs for death-censored graft failure with right kidneys before and after 6 months were 1.11 (95% CI, 1.06-1.16) and 0.96 (95% CI, 0.93-0.99), respectively; the corresonding aHRs for mortality were 0.99 (95% CI, 0.93-1.04) and 1.00 (95% CI, 0.98-1.03), respectively.

LIMITATIONS

Registry data, different transplant eras, reasons for kidney side unavailable.

CONCLUSIONS

There is modest association for transplantation of right kidneys with DGF and graft loss within the first 6 months, which is lost beyond this time point. These findings do not support the use of laterality of deceased-donor kidneys as an important factor in organ acceptance decisions.

Predicting urine output after kidney transplantation: development and internal validation of a nomogram for clinical use

Purpose:

To analyze pre-transplantation and early postoperative factors affecting post-transplantation urine output and develop a predictive nomogram.

Patients and Methods:

Retrospective analysis of non-preemptive first transplanted adult patients between 2001-2016. The outcomes were hourly diuresis in mL/Kg in the 1^st (UO₁) and 8^th (UO₈) postoperative days (POD). Predictors for both UO₁ and UO₈ were cold ischemia time (CIT), patient and donor age and sex, HLA I and II compatibility, pre-transplantation duration of renal replacement therapy (RRT), cause of ESRD (ESRD) and immunosuppressive regimen. UO₈ predictors also included UO₁, 1^st/0^th POD plasma creatinine concentration ratio (Cr_1/0), and occurrence of acute cellular rejection (AR). Multivariable linear regression was employed to produce nomograms for UO₁ and UO₈.

Results:

Four hundred and seventy-three patients were included, mostly deceased donor kidneys’ recipients (361, 70.4%). CIT inversely correlated with UO₁ and UO₈ (Spearman's p=-0.43 and −0.37). CR_1/0 inversely correlated with UO₈ (p=-0.47). On multivariable analysis UO₁ was mainly influenced by CIT, with additional influences of donor age and sex, HLA II matching and ESRD. UO₁ was the strongest predictor of UO₈, with significant influences of AR and ESRD.

Conclusions:

The predominant influence of CIT on UO₁ rapidly wanes and is replaced by indicators of functional recovery (mainly UO₁) and allograft's immunologic acceptance (AR absence). Mean absolute errors for nomograms were 0.08 mL/Kg h (UO₁) and 0.05 mL/Kg h (UO₈).

Impact of CYP3A5 genomic variances on clinical outcomes among African American kidney transplant recipients

Little is known about the impact of CYP3A5 polymorphisms on transplantation outcomes among African American (AA) kidney transplant recipients (KTRs). To assess this issue, clinical outcomes were compared between AA CYP3A5*1 expressers and nonexpressers. This retrospective cohort study analyzed AA KTRs. Biopsy-proven acute rejection (BPAR), delayed graft function (DGF), glomerular filtration rate (GFR), infections, and tacrolimus dosing requirements were examined in 106 immunologically high-risk AA kidney transplant patients over a 2-year follow-up period. In CYP3A5*1 expressers compared to nonexpressers, the incidence of BPAR was significantly higher in the first 6 months (13% vs 0%; P = .016) compared to 24 months (13% vs 7%; P = .521). Tacrolimus total daily dose at first therapeutic level was significantly higher in CYP3A5*1 expressers (12 mg/day) compared to nonexpressers (8 mg/day; P < .001). Compared to CYP3A5*1 nonexpressers, DGF incidence was significantly higher among CYP3A5*1 expressers (27.6% vs 6.7%; P = .006). By contrast, median GFR was significantly higher in CYP3A5*1 expressers compared to nonexpressers (54.5 mL/min vs 50.0 mL/min; P = .003) at 24 months. The findings from this retrospective study suggest that AAs with CYP3A5*1 expression require 50% more tacrolimus and have an increased incidence of DGF and acute rejection.

Influence of Cold Ischemia Time in Kidney Transplants From Small Pediatric Donors

Background

Clinicians may be reluctant to transplant small pediatric kidneys that have prolonged cold ischemia time (CIT) for fear of an additional deleterious effect because pediatric grafts are thought to be more sensitive to ischemia. We aimed to assess the risks associated with transplantation of small pediatric kidneys with prolonged CIT.

Methods

We performed a retrospective cohort study examining US registry data between 1998 and 2013 of adult first-time kidney-only recipients of small pediatric kidneys from donors weighing 10 to 20 kg, stratified by CIT levels of 0 to 18 (n = 1413), 19 to 30 (n = 1116), and longer than 30 (n = 338) hours.

Results

All-cause graft survival by CIT groups at 1-year was 92%, 88%, and 89%, respectively. 1-year risk-adjusted graft survival hazard ratios were significantly higher with CIT of 19 to 30 hours (adjusted hazard ratios, 1.37; 95% confidence interval, 1.04-1.81) and somewhat higher with CIT greater than 30 hours (adjusted hazard ratios, 1.24; 95% confidence interval, 0.82-1.88) relative to recipients with CIT 0 to 18 hours. There was little variation in the effect of CIT on graft survival when restricted to single kidney transplants only and no significant interaction of CIT category and single kidney transplantation (P = 0.93).

Conclusions

Although prolonged CIT is associated with lower early graft survival in small pediatric donor kidney transplants, absolute decreases in 1-year graft survival rates were 3% to 4%.

Impact of a quality improvement project on deceased organ donor management

CONTEXT

Donors showed poor glucose control in the period between declaration of brain death and organ recovery. The level of hyperglycemia in the donors was associated with a decline in terminal renal function.

OBJECTIVE

To determine whether implementation of a quality improvement project improved glucose control and preserved renal function in deceased organ donors.

METHODS

Data collected retrospectively included demographics, medical history, mechanism of death, laboratory values, and data from the United Network for Organ Sharing.

RESULTS

After implementation of the quality improvement project, deceased donors had significantly lower mean glucose concentrations (mean [SD], 162 [44] vs 212 [42] mg/dL; P<.001) and prerecovery glucose concentration (143 [66] vs 241 [69] mg/dL; P<.001). When the donor cohorts from before and after the quality improvement project were analyzed together, mean glucose concentration remained a significant predictor of terminal creatinine level (P<.001). Multivariate analysis of delayed graft function in kidney recipients matched to donors indicated that higher terminal creatinine level was associated with delayed graft function in recipients (P<.001).

CONCLUSION

The quality improvement project improved donor glucose homeostasis, and the data confirm that poor glucose homeostasis is associated with worsening terminal renal function.

Ischemia and reperfusion injury in renal transplantation: hemodynamic and immunological paradigms

Ischemia and reperfusion injury is an inevitable event in renal transplantation. The most important consequences are delayed graft function, longer length of stay, higher hospital costs, high risk of acute rejection, and negative impact of long-term follow-up. Currently, many factors are involved in their pathophysiology and could be classified into two different paradigms for education purposes: hemodynamic and immune. The hemodynamic paradigm is described as the reduction of oxygen delivery due to blood flow interruption, involving many hormone systems, and oxygen-free radicals produced after reperfusion. The immune paradigm has been recently described and involves immune system cells, especially T cells, with a central role in this injury. According to these concepts, new strategies to prevent ischemia and reperfusion injury have been studied, particularly the more physiological forms of storing the kidney, such as the pump machine and the use of antilymphocyte antibody therapy before reperfusion. Pump machine perfusion reduces delayed graft function prevalence and length of stay at hospital, and increases long-term graft survival. The use of antilymphocyte antibody therapy before reperfusion, such as Thymoglobulin™, can reduce the prevalence of delayed graft function and chronic graft dysfunction.

Is delayed graft function causally associated with long-term outcomes after kidney transplantation? Instrumental variable analysis

BACKGROUND

Although some studies have found an association between delayed graft function (DGF) after kidney transplantation and worse long-term outcomes, a causal relationship remains controversial. We investigated this relationship using an instrumental variables model (IVM), a quasi-randomization technique for drawing causal inferences.

METHODS

We identified 80,690 adult, deceased-donor, kidney-only transplant recipients from the Scientific Registry of Transplant Recipients between 1997 and 2010. We used cold ischemia time (CIT) as an instrument to test the hypothesis that DGF causes death-censored graft failure and mortality at 1 and 5 years after transplantation, controlling for an array of characteristics known to affect patient and graft survival. We compared our IVM results with a multivariable linear probability model.

RESULTS

DGF occurred in 27% of our sample. Graft failure rates at 1 and 5 years were 6% and 22%, respectively, and 1-year and 5-year mortality rates were 5% and 20%, respectively. In the linear probability model, DGF was associated with increased risk of both graft failure and mortality at 1 and 5 years (P<0.001). In the IVM, we found evidence suggesting a causal relationship between DGF and death-censored graft failure at both 1 year (13.5% increase; P<0.001) and 5 years (16.2% increase; P<0.001) and between DGF and mortality at both 1 year (7.1% increase; P<0.001) and 5 years (11.0% increase; P<0.01). Results were robust to exclusion of lower quality as well as pumped kidneys and use of a creatinine-based definition for DGF.

CONCLUSION

Instrumental variables analysis supports a causal relationship between DGF and both graft failure and mortality.

Recipient and donor body mass index as important risk factors for delayed kidney graft function

BACKGROUND

Obesity is increasingly impacting the overall health status and the global costs for health care. The increase in body mass index (BMI) is also observed in kidney allograft recipients and deceased organ donors.

METHODS

In a retrospective single-center study, we analyzed 1132 deceased donor kidney grafts, transplanted at our institution between 2000 and 2009 for recipient and donor BMI and its correlation with delayed graft function (DGF). Recipients/donors were classified according to their BMI (<18.5, 18.5-24.9, 25-29.9, and >30 kg/m(2)). DGF was defined as requirement for one dialysis within the first week after transplantation.

RESULTS

Overall DGF rate was 32.4%, mean recipient BMI was 23.64 ± 3.75 kg/m(2), and mean donor BMI was 24.69 ± 3.44 kg/m(2). DGF rate was 25.2%, 29.8%, 40.9%, and 52.6% in recipients with BMI less than 18.5, 18.5 to 24.9, 25 to 29.9, and more than 30 kg/m, respectively (P<0.0001). Donor BMI less than 18.5, 18.5 to 24.9, 25 to 29.9, more than 30 kg/m(2) resulted in a DGF rate of 22.5%, 31.0%, 37.3%, and 51.2% (P < 0.0001). Multivariate analysis revealed recipient BMI and dialysis duration as independent risk factors for DGF. DGF results in inferior 1- and 5-year graft and patient survival.

CONCLUSION

Recipient and donor BMI correlate with the incidence of DGF. Awareness thereof should have an impact on peri- and posttransplant measures in renal transplant recipients.

Influence of CIT-induced DGF on kidney transplant outcomes

Increased cold ischemia time (CIT) predisposes to delayed graft function (DGF). DGF is considered a risk factor for graft failure after kidney transplantation, but DGF has multiple etiologies. To analyze the risk of CIT-induced DGF on graft survival, we evaluated paired deceased-donor kidneys (derived from the same donor transplanted to different recipients) in which one donor resulted in DGF and the other did not, using national Scientific Registry of Transplant Recipients data between 2000 and 2009. Of 54 565 kidney donors, 15 833 were excluded for mate kidney non-transplantation, 27 340 because both or neither kidney developed DGF and 2310 for same/unknown CIT. The remaining 9082 donors (18 164 recipients) were analyzed. The adjusted odds (aOR) of DGF were significantly higher when CIT was longer by ≥ 1 h (aOR 1.81, 95% CI 1.7-2.0), ≥ 5 h (aOR 2.5, 95% CI 2.3-2.9), ≥ 10 h (aOR 3.3, 95% CI 2.7-2.9) and ≥ 15 h (aOR 4.4, 95% CI 3.4-5.8) compared to shorter CIT transplants. In the multivariable models adjusted for recipient characteristics, graft survival between paired donor transplants, with and without DGF, were similar. These results suggest that DGF, specifically induced by prolonged CIT, has limited bearing on long-term outcomes, which may have important implications for kidney utilization.

A risk prediction model for delayed graft function in the current era of deceased donor renal transplantation

Delayed graft function (DGF) impacts short- and long-term outcomes. We present a model for predicting DGF after renal transplantation. A multivariable logistic regression analysis of 24,337 deceased donor renal transplant recipients (2003-2006) was performed. We developed a nomogram, depicting relative contribution of risk factors, and a novel web-based calculator (http://www.transplantcalculator.com/DGF) as an easily accessible tool for predicting DGF. Risk factors in the modern era were compared with their relative impact in an earlier era (1995-1998). Although the impact of many risk factors remained similar over time, weight of immunological factors attenuated, while impact of donor renal function increased by 2-fold. This may reflect advances in immunosuppression and increased utilization of kidneys from expanded criteria donors (ECDs) in the modern era. The most significant factors associated with DGF were cold ischemia time, donor creatinine, body mass index, donation after cardiac death and donor age. In addition to predicting DGF, the model predicted graft failure. A 25-50% probability of DGF was associated with a 50% increased risk of graft failure relative to a DGF risk < 25%, whereas a > 50% DGF risk was associated with a 2-fold increased risk of graft failure. This tool is useful for predicting DGF and long-term outcomes at the time of transplant.

Protective effect of T cell depletion in murine renal ischemia-reperfusion injury

BACKGROUND

Ischemia-reperfusion injury (IRI) is the main cause of acute renal failure in both allograft and native kidney. Studies using T cell knockout mice have established an important role for T cells in renal IRI. T cell depletion strategies are effective in human allograft rejection. However, it is not known whether those are effective in renal IRI. Therefore, the effect of T cell depletion in a murine model of renal IRI using well-characterized antibodies (Abs) that have been effective in preventing experimental allograft rejection was studied.

METHODS

T cell depleting Abs to CD4 (GK1.5), CD8 (2.43) or pan-T cells (30.H12) were purified from hybridoma culture supernatant. Thymectomized C57BL/6 mice, treated with different combinations of T cell depleting Abs, underwent 30 min of bilateral renal IRI, followed by assessment of renal function, structure, and degree of T cell depletion in spleen, lymph nodes, and peripheral blood by flow cytometry.

RESULTS

Mice given both GK1.5 and 2.43 had considerable CD4 and CD8 cell depletion but no protection of renal function after ischemia-reperfusion (I/R) as measured by the rise in serum creatinine. However, when GK1.5 and 2.43 was administered combined with 30.H12, which more effectively depleted CD4 T cell numbers, a significant protection of renal function and structure was observed after I/R. Antibody combinations did not significantly alter other leukocyte populations.

CONCLUSIONS

These data demonstrate that T cell depletion can improve the course of experimental renal IRI. However, more aggressive T cell depletion strategies were required compared with that needed to prevent experimental allograft rejection.

Endothelin receptor blockade during hypothermic perfusion preservation mitigates the adverse effect of preretrieval warm ischemic injury on posttransplant glomerular filtration rate

BACKGROUND

Preretrieval warm ischemic injury predisposes to both short-term and long-term dysfunction of cadaveric renal allografts. We previously reported that the excretion of the vasoactive peptide, endothelin (ET), is significantly increased during hypothermic perfusion preservation (HPP) of kidneys subjected to preretrieval warm ischemia compared with nonischemic controls. As such, the purpose of this study was to determine if endothelin receptor (ET-R) blockade during HPP would improve glomerular filtration rate (GFR) of kidneys subjected to preretrieval warm ischemia when measured in situ at 2 weeks after transplantation (Tx).

METHODS

The left kidney was retrieved from 300-g Lewis rats after in situ cold perfusion and transplanted after 2 hr of HPP. A 30-min period of preretrieval warm ischemia was induced. Kidneys were divided into four groups: nonischemic controls (n=9), ischemic (isch) kidneys not receiving ET-R blockade during HPP (n=7), isch kidneys receiving the ETA receptor antagonist (n=7), and isch kidneys receiving the ETA/B receptor antagonist (n=8). ET-R blockade was induced by adding the ETA, A-147627, or the ETA/B, A-182086, receptor antagonist (Abbott Laboratories, Abbott Park, IL) directly to the preservation solution (5x10-6M). The kidneys were then isografted into genetically identical Lewis rats and GFR, determined by measurement of urinary iohexol clearance, measured 2 weeks after Tx.

RESULTS

Two-week GFRs (mL/min) for each of the study cohorts are as follows: nonischemic controls, 1.18+/-0.11; ischemic (isch) only, 0.57+/-0.08 (P< or =0.05 vs. nonischemic controls); isch + ETA blockade, 0.95+/-0.15 (P< or =0.05 vs. isch only); isch + ETA/B blockade, 0.90+/-0.08 (P< or =0.05 vs. isch only).

CONCLUSION

Addition of an ETA, A-147627, or an ETA/B, A-182086, receptor antagonist to preservation solution used during HPP of kidneys subjected to preretrieval warm ischemia resulted in a normalization of GFR measured 2 weeks after Tx. The data provide a basis for further investigation of the impact of ET-R blockade on both the short- and long-term adverse effects of preretrieval warm ischemic injury in cadaveric renal Tx.

Increased urinary excretion of endothelin during hypothermic perfusion preservation in kidneys subjected to preretrieval warm ischemic injury

The purpose of the study was two-fold: 1) to determine whether endothelin (ET) levels could be detected in the ureteral effluent during hypothermic perfusion preservation (HPP) and; 2) to determine whether preretrieval warm ischemic (WI) injury is associated with increased ureteral excretion of ET. In situ pre-WI injury was induced in Lewis rats (n=10) by a 30-min extrinsic occlusion of the suprarenal aorta. The left kidney underwent 16 hr of HPP, and ureteral effluent (UE) from ischemic and control kidneys (n=10) was collected over 16 hr of HPP. The UE ET concentration and total ET excretion over 16 hr of HPP were significantly higher in kidneys subjected to pre-WI injury compared with nonischemic controls. Kidneys subjected to pre-WI injury can be distinguished from nonischemic control kidneys during HPP by a significantly higher concentration of ET in the UE and a higher overall excretion of ET during HPP.

Predictive factors for delayed graft function (DGF) and its impact on renal graft survival in children: a report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS)

We define delayed graft function (DGF) as the need for dialysis during the first post-transplant week. We analyzed 5272 transplants, of which 2486 were of living donor (LD) and 2786 were of cadaver donor (CD) origin. Twelve per cent (620/5272) of all patients developed DGF. Donor specific rates were 5.6% for LD and 19.1% for CD patients. Factors predictive of DGF in CD patients were: African-American race (25%), prolonged cold ischemia (24%), absence of T-cell induction antibody therapy and absence of HLA-DR matching. The relative risk (RR) for graft failure due to DGF was 6.02 (p < 0.001) in LD patients and 2.58 (p < 0.001) for CD recipients. Two-year graft survival (GS) in LD patients without DGF was 89.6%, compared to 41.6% for those with DGF (p < 0.001); in CD patients it was 80.2% and 49.5%, respectively (p < 0.001). Censoring for primary non-function, GS for LD patients with a functioning graft at 30 d post-transplant and no DGF was 91.5%, compared to 70.1% for those with DGF (p < 0.001); GS for CD patients was 83.8% and 68.7%, respectively (p < 0.001). However, when patients whose grafts had failed during the first year were censored no differences in GS were noted between patients with and without DGF for either LD or CD recipients. To determine whether DGF acts as an independent risk factor for graft failure, patients were segregated into four groups: rejection with DGF; rejection without DGF; DGF without rejection; and no DGF, no rejection. When these groups were compared DGF emerged as an independent risk factor for graft failure. This large study reviewing pediatric renal transplantation over 10 yr clearly delineates the role of DGF as a major risk factor for graft failure.