"Nature versus nurture" study of deceased-donor pairs in kidney transplantation

Mechanical Preservation and Delayed Graft Function and Hospital Length of Stay as Deployed in the United States: Analysis of the Last Decade

BACKGROUND Mechanical preservation (MP) of deceased donor kidney transplants showed a 30% to 50% reduction in delayed graft function (DGF) as defined by dialysis in the first week, when compared with cold storage. DGF is associated with longer hospital stays and increased costs. In this study, we sought to understand the impact of MP on rates of DGF and length of hospital stays in a contemporary cohort of deceased donor kidney transplants in the United States. MATERIAL AND METHODS All single deceased donor kidney transplants performed between January 1, 2010, and September 2, 2020, were identified in the Scientific Registry of Transplant Recipients database. Donor kidneys were considered pumped if the transplant center received the kidney on the pump. RESULTS Multivariate logistic regression showed that MP had similar odds of reduction of DGF for all subsets of donors. The unadjusted rate of DGF for pumped brain-dead standard criteria donor (BDSCD) recipients was similar to that of donors stored on ice. The rate of DGF for expanded criteria donors (ECD) and donors after cardiac death (DCD) was lower in the recipients who received MP. The similar DGF rates in BDSCD donor recipients were due to longer cold ischemia times in MP kidneys. The lower DGF rates seen in ECD and DCD recipients of pumped kidneys did not translate into a shortened length of hospitalization after transplant. CONCLUSIONS As currently deployed, only DCD and ECD donor recipients of MP kidneys experienced a lower DGF rate. In all subsets of patients, MP did not appreciably shorten the hospital length of stay.

An interleukin 6-based genetic risk score strengthened with interleukin 10 polymorphisms associated with long-term kidney allograft outcomes

Of all kidney transplants, half are still lost in the first decade after transplantation. Here, using genetics, we probed whether interleukin 6 (IL-6) could be a target in kidney transplantation to improve graft survival. Additionally, we investigated if a genetic risk score (GRS) based on IL6 and IL10 variants could improve prognostication of graft loss. In a prospective cohort study, DNA of 1271 donor-recipient kidney transplant pairs was analyzed for the presence of IL6, IL6R, IL10, IL10RA, and IL10RB variants. These polymorphisms and their GRS were then associated with 15-year death-censored allograft survival. The C|C-genotype of the IL6 polymorphism in donor kidneys and the combined C|C-genotype in donor-recipient pairs were both associated with a reduced risk of graft loss (p = .043 and p = .042, respectively). Additionally, the GRS based on IL6, IL6R, IL10, IL10RA, and IL10RB variants was independently associated with the risk of graft loss (HR 1.53, 95%-CI [1.32-1.84]; p < .001). Notably, the GRS improved risk stratification and prediction of graft loss beyond the level of contemporary clinical markers. Our findings reveal the merits of a polygenic IL-6-based risk score strengthened with IL-10- polymorphisms for the prognostication and risk stratification of late graft failure in kidney transplantation.

In kidney recipients from the same deceased donor, discordance in delayed graft function is associated with the worst outcomes

Delayed graft function(DGF) is a common complication among deceased donor kidney transplant recipients(DDKTs) and is associated with worse outcomes. The effect on outcomes of concordance versus discordance in DGF between two different recipients of kidneys from the same donor is largely unknown. We reviewed all adult DDKTs for which both kidneys were transplanted to two different recipients at our center between 2014-2019. DDKTs were divided into four groups based on the DGF status: concordance no DGF(cc-no-DGF); discordance no DGF(dd-no-DGF); discordance DGF(dd-DGF) and concordance in DGF(cc-DGF). Acute rejection (AR) and death censored graft failure (DCGF) were outcomes of interest. A total of 578 DDKTs fulfilled our selection criteria, 280 were in cc-no-DGF, 83 in dd-no-DGF, 83 in dd-DGF, and 132 in cc-DGF. Compared to cc-no-DGF, in univariate analysis, dd-DGF was associated with an increased risk of AR(HR:1.60; 95% CI:1.0-2.56) but cc-DGF was not(HR:1.01; 95% CI:0.63-1.62). dd-DGF was not associated with an increased risk of AR in multivariate analysis. In multivariate analysis, dd-DGF was associated with an increased risk of DCGF (HR: 2.70; 95% CI: 1.05-6.93) but cc-DGF was not (HR:2.36; 95% CI:0.97-5.70). Discordance in DGF is associated with worse outcomes and may need close follow-up and monitoring to improve the outcomes. This article is protected by copyright. All rights reserved.

Transplant and Recipient Factors in Prediction of Kidney Transplant Outcomes: A UK-Wide Paired Analysis

Background: In kidney transplantation, the relative contribution of various donor, procedure and recipient-related factors on clinical outcomes is unknown. Previous paired studies have largely focused on examining factors predicting early outcomes, where the effect of donor factors is thought to be most important. Here, we sought to examine the relationship between early and long-term outcomes in a UK-wide paired kidney analysis. Methods: UK Transplant Registry data covering 24,090 kidney transplants performed between 2001–2018, where both kidneys from each donor were transplanted, were analysed. Case-control studies were constructed using matched pairs of kidneys from the same donor discordant for outcome, to delineate the impact of transplant and recipient factors on longer-term outcomes. Results: Multivariable conditional logistic regression identified HLA mismatch as an important predictor of prolonged delayed graft function (DGF), in the context of a paired study controlling for the influence of donor factors, even when adjusting for early acute rejection. Prolonged DGF, but not human leucocyte antigen (HLA) mismatch, strongly predicted 12-month graft function, and impaired 12-month graft function was associated with an increased risk of graft failure. Conclusions: This study indicates prolonged DGF is associated with adverse long-term outcomes and suggests that alloimmunity may contribute to prolonged DGF by a mechanism distinct from typical early acute rejection.

Rejection-associated Phenotype of De Novo Thrombotic Microangiopathy Represents a Risk for Premature Graft Loss

Supplemental Digital Content is available in the text.

Background.

Thrombotic microangiopathy (TMA) significantly affects kidney graft survival, but its pathophysiology remains poorly understood.

Methods.

In this multicenter, retrospective, case–control paired study designed to control for donor-associated risks, we assessed the recipients’ risk factors for de novo TMA development and its effects on graft survival. The study group consists of patients with TMA found in case biopsies from 2000 to 2019 (n = 93), and the control group consists of recipients of paired kidney grafts (n = 93). Graft follow-up was initiated at the time of TMA diagnosis and at the same time in the corresponding paired kidney graft.

Results.

The TMA group displayed higher peak panel-reactive antibodies, more frequent retransplantation status, and longer cold ischemia time in univariable analysis. In the multivariable regression model, longer cold ischemia times (odds ratio, 1.18; 95% confidence interval [CI], 1.01-1.39; P = 0.043) and higher peak pretransplant panel-reactive antibodies (odds ratio, 1.03; 95% CI, 1.01-1.06; P = 0.005) were found to be associated with increased risk of de novo TMA. The risk of graft failure was higher in the TMA group at 5 y (hazard ratio [HR], 3.99; 95% CI, 2.04-7.84; P < 0.0001). Concomitant rejection significantly affected graft prognosis at 5 y (HR, 6.36; 95% CI, 2.92-13.87; P < 0.001). De novo TMA associated with the active antibody-mediated rejection was associated with higher risk of graft failure at 5 y (HR, 3.43; 95% CI, 1.69-6.98; P < 0.001) compared with other TMA.

Conclusions.

Longer cold ischemia and allosensitization play a role in de novo TMA development, whereas TMA as a part of active antibody-mediated rejection was associated with the highest risk for premature graft loss.

Kidney-intrinsic factors determine the severity of ischemia/reperfusion injury in a mouse model of delayed graft function

Delayed graft function due to transplant ischemia/reperfusion injury adversely affects up to 50% of deceased-donor kidney transplant recipients. However, key factors contributing to the severity of ischemia/reperfusion injury remain unclear. Here, using a clinically relevant mouse model of delayed graft function, we demonstrated that donor genetic background and kidney-intrinsic MyD88/Trif-dependent innate immunity were key determinants of delayed graft function. Functional deterioration of kidney grafts directly corresponded with the duration of cold ischemia time. The graft dysfunction became irreversible after cold ischemia time exceeded six hours. When cold ischemia time reached four hours, kidney grafts displayed histological features reflective of delayed graft function seen in clinical kidney transplantation. Notably, kidneys of B6 mice exhibited significantly more severe histological and functional impairment than kidneys of C3H or BALB/c mice, regardless of recipient strains or alloreactivities. Furthermore, allografts of B6 mice also showed an upregulation of IL-6, neutrophil gelatinase-associated lipocalin, and endoplasmic reticulum stress genes, as well as an increased influx of host neutrophils and memory CD8 T-cells. In contrast, donor MyD88/Trif deficiency inhibited neutrophil influx and decreased the expression of IL-6 and endoplasmic reticulum stress genes, along with improved graft function and prolonged allograft survival. Thus, kidney-intrinsic factors involving genetic characteristics and innate immunity serve as critical determinants of the severity of delayed graft function. This preclinical murine model allows for further investigations of the mechanisms underlying delayed graft function.

Quantifying Donor Effects on Transplant Outcomes Using Kidney Pairs from Deceased Donors

BACKGROUND AND OBJECTIVES

In kidney transplantation, the relative contribution of donor versus other factors on clinical outcomes is unknown. We sought to quantify overall donor effects on transplant outcomes for kidney donations from deceased donors.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

For paired donations from deceased donors resulting in transplants to different recipients, the magnitude of donor effects can be quantified by examining the excess of concordant outcomes within kidney pairs beyond chance concordance. Using data from the Organ Procurement and Transplantation Network between the years 2013 and 2017, we examined concordance measures for delayed graft function, death-censored 1-year graft failure, and death-censored 3-year graft failure. The concordance measures were excess relative risk, excess absolute risk, and the fixation index (where zero is no concordance and one is perfect concordance). We further examined concordance in strata of kidneys with similar values of the Kidney Donor Profile Index, a common metric of organ quality.

RESULTS

If the transplant of the kidney mate resulted in delayed graft function, risk for delayed graft function was 19% higher (95% confidence interval [95% CI], 18% to 20%), or 1.76-fold higher (95% CI, 1.73- to 1.80-fold), than baseline. If a kidney graft failed within 1 year, then the kidney mate's risk of failure was 6% higher (95% CI, 4% to 9%), or 2.85-fold higher (95% CI, 2.25- to 3.48-fold), than baseline. For 3-year graft failure, the excess absolute risk was 7% (95% CI, 4% to 10%) but excess relative risk was smaller, 1.91-fold (95% CI, 1.56- to 2.28-fold). Fixation indices were 0.25 for delayed graft function (95% CI, 0.24 to 0.27), 0.07 for 1-year graft failure (95% CI, 0.04 to 0.09), and 0.07 for 3-year graft failure (95% CI, 0.04 to 0.10). Results were similar in strata of kidneys with a similar Kidney Donor Profile Index.

CONCLUSIONS

Overall results indicated that the donor constitution has small or moderate effect on post-transplant clinical outcomes.

Xenotransplantation: Progress Along Paths Uncertain from Models to Application

For more than a century, transplantation of tissues and organs from animals into man, xenotransplantation, has been viewed as a potential way to treat disease. Ironically, interest in xenotransplantation was fueled especially by successful application of allotransplantation, that is, transplantation of human tissue and organs, as a treatment for a variety of diseases, especially organ failure because scarcity of human tissues limited allotransplantation to a fraction of those who could benefit. In principle, use of animals such as pigs as a source of transplants would allow transplantation to exert a vastly greater impact than allotransplantation on medicine and public health. However, biological barriers to xenotransplantation, including immunity of the recipient, incompatibility of biological systems, and transmission of novel infectious agents, are believed to exceed the barriers to allotransplantation and presently to hinder clinical applications. One way potentially to address the barriers to xenotransplantation is by genetic engineering animal sources. The last 2 decades have brought progressive advances in approaches that can be applied to genetic modification of large animals. Application of these approaches to genetic engineering of pigs has contributed to dramatic improvement in the outcome of experimental xenografts in nonhuman primates and have encouraged the development of a new type of xenograft, a reverse xenograft, in which human stem cells are introduced into pigs under conditions that support differentiation and expansion into functional tissues and potentially organs. These advances make it appropriate to consider the potential limitation of genetic engineering and of current models for advancing the clinical applications of xenotransplantation and reverse xenotransplantation.

Accommodation in ABO-incompatible organ transplants

Accommodation refers to a condition in which a transplant (or any tissue) appears to resist immune-mediated injury and loss of function. Accommodation was discovered and has been explored most thoroughly in ABO-incompatible kidney transplantation. In this setting, kidney transplants bearing blood group A or B antigens often are found to function normally in recipients who lack and hence produce antibodies directed against the corresponding antigens. Whether accommodation is owed to changes in anti-blood group antibodies, changes in antigen or a change in the response of the transplant to antibody binding are critically reviewed and a new working model that allows for the kinetics of development of accommodation is put forth. Regardless of how accommodation develops, observations on the fate of ABO-incompatible transplants offer lessons applicable more broadly in transplantation and in other fields.

Pretransplant IgA-Anti-Beta 2 Glycoprotein I Antibodies As a Predictor of Early Graft Thrombosis after Renal Transplantation in the Clinical Practice: A Multicenter and Prospective Study

Background

Graft thrombosis is a devastating complication after renal transplantation. We recently described the association of anti-beta-2-glycoprotein-I (IgA-ab2GP1) antibodies with early graft loss mainly caused by thrombosis in a monocenter study.

Methods

Multicenter prospective observational cohort study.

Setting and participants

Seven hundred forty patients from five hospitals of the Spanish Forum Renal Group transplanted from 2000 to 2002 were prospectively followed-up for 10 years.

Outcomes

Early graft loss and graft loss by thrombosis.

Measurements

The presence of IgA anti-B2GP1 antibodies in pretransplant serum was examined using the same methodology in all the patients.

Results

At transplantation, 288 patients were positive for IgA-B2GP1 (39%, Group-1) and the remaining were negative (Group-2). Graft loss at 6 months was higher in Group-1 (12.5 vs. 4.2% p < 0.001), vessel thrombosis being the most frequent cause of early graft loss, especially in Group-1 (6.9 vs. 0.4% p < 0.001). IgA-aB2GP1 was the most important independent risk factor for graft thrombosis (hazard ratio: 13.83; 95% CI: 3.17-60.27, p < 0.001). Furthermore, the, presence of IgA-aB2GP1 was associated with early graft loss and delayed graft function. At 10 years, survival figures were also lower in Group-1: graft survival was lower compared with Group-2 (60.4 vs. 76.8%, p < 0.001). Mortality was significantly higher in Group-1 (19.8 vs. 12.2%, p = 0.005).

Limitations

Patients were obtained during a 3-year period (1 January 2000-31 December 2002) and kidneys were only transplanted from brain-dead donors. Nowadays, the patients are older and the percentage of sensitized and retransplants is high.

Conclusion

In a prospective observational multicenter study, we were able to corroborate that pretransplant presence of IgA-aB2GP1 was the main risk factor for graft thrombosis and early graft loss. Therefore, a prospective study is needed to evaluate the efficacy and safety of prophylactic anticoagulation to avoid this severe complication.

Delayed graft function and its management in children

Delayed graft function (DGF) is commonly defined as the requirement for dialysis within the first 7 days following renal transplantation. The major underlying mechanism is related to ischaemia/reperfusion injury, which includes microvascular inflammation and cell death and apoptosis, and to the regeneration processes. Several clinical factors related to donor, recipient and organ procurement/transplantation procedures may increase the risk of DGF, including donor cardiovascular instability, older donor age, donor creatinine concentration, long cold ischaemia time and marked body mass index of both the donor and recipient. Some of these parameters have been used in specific predictive formulas created to assess the risk of DGF. A variety of other pre-, intra- and post-transplant clinical factors may also increase the risk of DGF, such as potential drug nephrotoxicity, surgical problems and/or hyperimmunization of the recipient. DGF may decrease the long-term graft function, but data on this effect are inconsistent, partially due to the many different types of organ donation. Relevant management strategies may be classified into the classic clinical approach, which has the aim of minimizing the individual risk factors of DGF, and specific pharmacologic strategies, which are designed to prevent or treat ischaemia/reperfusion injury. Both strategies are currently being evaluated in clinical trials.

Re-transplants compared to primary kidney transplants recipients: a mate kidney paired analysis of the OPTN/UNOS database

Outcomes of kidney re-transplant recipients (RTR) were compared to primary recipients (FTR) from paired donor kidneys. Organ Procurement and Transplantation Network (OPTN) database was used to identify deceased donors (n = 6266) who donated one kidney to an RTR and the mate kidney to an FTR between January 2000 to December 2010. As compared to FTR, RTR were younger (45 vs. 52 yr, p < 0.001) and had higher proportion of plasma reactive antibody >80 (25% vs 7%, p < 0.001). There were higher 0 mismatches in RTR (19% vs. 16%, p < 0.001). There were more pre-emptive transplants in RTR (24% vs. 21%, p = 0.002). Delayed graft function (28% vs. 25%, p = 0.007) was higher in RTR. Patient survival was similar in FTR and RTR groups at one, three, and five yr (95.7%, 90.2%, and 82.5% vs. 95.2%, 89.8% and 82.7%). Allograft survival rates were higher in FTR group compared to RTR group at one, three, and five yr (91.1%, 82.4%, and 70.9% vs. 87.8%, 77.4%, and 66.1% p < 0.001). Death-censored allograft survival rates were higher in FTR group at one, three, and five yr (91.3%, 82.7% and 71.4% vs. 88%, 77.7% and 66.5% p < 0.001). In today's era of modern immunosuppression, graft survival in RTR has improved but remains inferior to FTR when controlling for donor factors.

Associations between Deceased-Donor Urine Injury Biomarkers and Kidney Transplant Outcomes

Assessment of deceased-donor organ quality is integral to transplant allocation practices, but tools to more precisely measure donor kidney injury and better predict outcomes are needed. In this study, we assessed associations between injury biomarkers in deceased-donor urine and the following outcomes: donor AKI (stage 2 or greater), recipient delayed graft function (defined as dialysis in first week post-transplant), and recipient 6-month eGFR. We measured urinary concentrations of microalbumin, neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), IL-18, and liver-type fatty acid binding protein (L-FABP) from 1304 deceased donors at organ procurement, among whom 112 (9%) had AKI. Each biomarker strongly associated with AKI in adjusted analyses. Among 2441 kidney transplant recipients, 31% experienced delayed graft function, and mean±SD 6-month eGFR was 55.7±23.5 ml/min per 1.73 m(2) In analyses adjusted for donor and recipient characteristics, higher donor urinary NGAL concentrations associated with recipient delayed graft function (highest versus lowest NGAL tertile relative risk, 1.21; 95% confidence interval, 1.02 to 1.43). Linear regression analyses of 6-month recipient renal function demonstrated that higher urinary NGAL and L-FABP concentrations associated with slightly lower 6-month eGFR only among recipients without delayed graft function. In summary, donor urine injury biomarkers strongly associate with donor AKI but provide limited value in predicting delayed graft function or early allograft function after transplant.

Metabolomic analysis of perfusate during hypothermic machine perfusion of human cadaveric kidneys

BACKGROUND

The metabolic processes occurring within the preserved kidney during hypothermic machine perfusion (HMP) are not well characterized. The aim of this study was to use nuclear magnetic resonance (NMR) spectroscopy to examine the metabolomic profile of HMP perfusate from human cadaveric kidneys awaiting transplantation and to identify possible discriminators between the profiles of kidneys with delayed graft function (DGF) and immediate graft function (IGF).

METHODS

Perfusates from HMP kidneys were sampled at 45 min and 4 hr of preservation with the LifePort Kidney Transporter 1.0 (Organ Recovery Systems, Chicago, IL) using KPS-1. Prepared samples underwent 1-D Proton-NMR spectroscopy, and resultant spectra were analyzed. Clinical parameters were collected prospectively.

RESULTS

Perfusate of 26 transplanted cadaveric kidneys was analyzed; 19(73%) with IGF and 7(27%) with DGF. Glucose concentrations were significantly lower in DGF kidneys compared to those with IGF at both 45 min (7.772 vs. 9.459 mM, P = 0.006) and 4 hr (8.202 vs. 10.235 mM, P = 0.003). Concentrations of inosine and leucine were significantly different between DGF and IGF kidneys at 45 min (0.002 vs. 0.013 mM, P = 0.009 and 0.011 vs. 0.006 mM, P = 0.036), and gluconate levels were also significantly different between DGF and IGF kidneys at 4 hr (49.099 vs. 59.513 mM, P = 0.009).

CONCLUSION

Significant metabolic activity may be occurring in kidneys during HMP. The NMR spectroscopy of the perfusate can identify differences in the metabolomic profiles of DGF and IGF kidneys that might have a predictive role in viability assessment. Modification of harmful metabolic processes may improve outcomes for HMP kidneys.

Glutathione S-transferase iso-enzymes in perfusate from pumped kidneys are associated with delayed graft function

Accurate and reliable assessment tools are needed in transplantation. The objective of this prospective, multi-center study was to determine the associations of the alpha and pi iso-enzymes of glutathione S-transferase (GST), measured from perfusate solution at the start and end (base and post) of kidney allograft machine perfusion, with subsequent delayed graft function (DGF). We also compared GST iso-enzyme perfusate levels from discarded versus transplanted kidneys. A total of 428 kidneys were linked to outcomes as recorded by the United Network of Organ Sharing. DGF, defined as any dialysis in the first week of transplant, occurred in 141 recipients (32%). Alpha- and pi-GST levels significantly increased during machine perfusion. The adjusted relative risks (95% confidence interval) of DGF with each log-unit increase in base and post pi-GST were 1.14 (1.0-1.3) and 1.36 (1.1-1.8), respectively. Alpha-GST was not independently associated with DGF. There were no significant differences in GST values between discarded and transplanted kidneys, though renal resistance was significantly higher in discarded kidneys. We found pi-GST at the end of machine perfusion to be independently associated with DGF. Further studies should elucidate the utility of GST for identifying injured kidneys with regard to organ allocation, discard and recipient management decisions.

Peri-operative hyperglycemia is associated with delayed graft function in deceased donor renal transplantation

Increasing evidence indicates that recipient diabetes is a risk factor for delayed graft function (DGF) after renal transplant and that peri-operative hyperglycemia increases ischemia-reperfusion injury. To evaluate whether peri-operative hyperglycemia as measured in the post-anesthesia care unit (PACU) after transplant is a risk factor for DGF, we retrospectively reviewed 976 adult recipients of deceased donor renal transplants between January 1, 1997 and December 1, 2004. Logistic regression was used to evaluate risk factors for DGF. In our final multivariate model, recipient blood glucose level in the PACU (odds ratio [OR] 1.10 per 25 unit increase, 95% confidence interval (CI) 1.14-2.46, p = 0.03) was a statistically significant predictor of DGF along with donor age (OR 1.02, 95% CI 1.01-1.03, p < 0.01), cold ischemia time (OR 1.04, 95% CI 1.02-1.07, p < 0.01), recipient male gender (OR 1.68, 95% CI 1.14-2.68, p = 0.01), and a panel-reactive antibody >30% (OR 1.92, 95% CI 1.20-3.05, p = 0.01). We conclude that recipient blood glucose measured in the PACU is associated with DGF and begs the question of whether improved peri-operative glucose control will decrease the incidence of DGF.

Concordance of outcomes of pairs of kidneys transplanted into different recipients

Kidney transplant outcomes are influenced by donor characteristics, including age and gender. Additional donor factors, both genetic and environmental, also influence graft outcome. We aim to assess the strength of donor factors in determining kidney transplant outcomes by comparing paired kidneys from a single donor transplanted into different recipients. We conducted a retrospective cohort study of outcomes of pairs of deceased donor kidneys transplanted in our centre between 1992 and 2008. We examined the relationship within pairs for eGFR at 1 year and at 5 years post-transplant using Spearman's Correlation and the concordance of pairs of transplant kidneys with respect to the occurrence of acute rejection and delayed graft function (DGF). A total of 652 recipient pairs were analysed. Spearman's correlation for eGFR was 0.36 at 1 year and 0.36 at 5 years post-transplant. The incidence of DGF was 11%. The odds ratio of DGF occurring if the contralateral kidney had DGF was 5.99 (95% CI, 3.19-11.25). There is a significant degree of relationship within pairs of kidneys transplanted from the same donor for serum creatinine at 1 year and 5 years post-transplant and also for the occurrence of delayed graft function.

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.

Deceased-donor kidney perfusate and urine biomarkers for kidney allograft outcomes: a systematic review

BACKGROUND

Accurate and reliable assessment of kidney quality before transplantation is needed to predict recipient outcomes and to optimize management and allocation of the allograft. The aim of this study was to systematically review the published literature on biomarkers in two mediums (the perfusate from deceased-donor kidneys receiving machine perfusion and deceased-donor urine) that were evaluated for their possible association with outcomes after kidney transplantation.

METHODS

We searched the Ovid Medline and Scopus databases using broad keywords related to deceased-donor biomarkers in kidney transplantation (limited to humans and the English language). Studies were included if they involved deceased-donor kidneys, measured perfusate or urine biomarkers and studied a possible relationship between biomarker concentrations and kidney allograft outcomes. Each included article was assessed for methodological quality.

RESULTS

Of 1430 abstracts screened, 29 studies met the inclusion criteria. Of these, 23 were studies of perfusate (16 biomarkers examined) and 6 were studies of urine (18 biomarkers examined). Only 3 studies (two perfusate) met the criteria of 'good' quality and only 12 were published since 2000. Perfusate lactate dehydrogenase, glutathione-S-transferase (GST) and aspartate transaminase were all found to be significantly associated with delayed graft function in a majority of their respective studies (6/9, 4/6 and 2/2 studies, respectively). Urine neutrophil gelatinase-associated lipocalin, GST, Trolox-equivalent antioxidant capacity and kidney injury molecule-1 were found to be significantly associated with allograft outcomes in single studies that examined diverse end points.

CONCLUSION

Higher quality studies are needed to investigate modern kidney injury biomarkers, to validate novel biomarkers in larger donor populations and to determine the incremental predictive value of biomarkers over traditional clinical variables.

Donor cause of brain death in renal transplantation: a predictive factor for graft function?

PURPOSE

Our aim was to evaluate the influence of donor cause of brain death on the results of kidney transplantation.

METHODS

This retrospective study included 896 consecutive deceased-donor renal transplantations performed between January 1, 2000, and December 31, 2009. We compared outcomes of grafts from donors after cerebrovascular accident (CVA; n = 371) versus head trauma (HT; n = 525).

RESULTS

Univariate analysis of pretransplantation data showed statistically significant differences (P < .05): among the following variables for the HT versus CVA groups respectively: recipient age (43.63 ± 13.2 y vs 49.80 ± 12.5 y); donor age (36.06 ± 16.6 y vs 52.57 ± 13.2 y) and time on dialysis (50.67 ± 45.034 mo vs 59.39 ± 46.3 mo). Regarding transplantation results, we observed that mean serum creatinine was significantly lower among HT recipient, at 1, 3, 6, 12, and 24 months after transplantation (P < .05). Chronic allograft nephropathy (CAN) and delayed graft function were higher among the CVA group. HT group kidneys showed significantly longer mean survival times than CVA group kidneys (102.7 ± 3.9 mo vs 94.8 ± 5.6 mo; log rank: P = .04). Upon multivariate analysis donor cause of death was not identified as an independent risk factor for graft survival or occurrence of chronic allograft nephropathy.

CONCLUSIONS

Transplantation results were better among the HT group. However multivariate regression analysis indicated that donor cause of death was not an independent risk factor for graft survival or occurrence of chronic allograft nephropathy.

Recipient risk factors associated with delayed graft function: a paired kidney analysis

BACKGROUND

Delayed graft function (DGF) is a common complication of deceased donor kidney transplantation that occurs because of a complex interplay between donor organ quality and the biologic milieu of the recipient. The purpose of the study is to better understand the recipient risk factors leading to DGF.

METHODS

We performed a retrospective cohort study using United Network for Organ sharing data and identified pairs of primary, adult kidney-only transplants that were procured from the same adult donor with discordant occurrence of DGF (i.e., one kidney of the pair had DGF).

RESULTS

A total of 5382 recipient pairs were analyzed. Recipients with DGF were more likely to be male (67% vs. 59%, P<0.01), African American (36% vs. 27%, P<0.01), obese (30% vs. 19%, P<0.01), diabetic (28% vs. 22%, P<0.01), on maintenance dialysis (92% vs. 83%, P<0.01), and to have longer wait-time (571 vs. 471 days, P<0.01), longer cold ischemia time (22 vs. 20 hr, P<0.01), and donor and recipient size mismatch (32% vs. 24%, P<0.01). Multivariable analyses confirmed these associations and identified panel reactive antibody more than 10% and low center volume as additional risk factors for DGF (odds ratio for panel reactive antibody >10%: 1.17, confidence interval 1.05-1.29, P<0.01; and odds ratio for <83 transplants/year: 1.29, confidence interval 1.17-1.44, P<0.01).

CONCLUSIONS

After fully matching for donor factors, many recipient characteristics were noted to be associated with DGF. Better management of modifiable recipient and transplant risk factors such as obesity, wait time, and cold time may help to reduce the occurrence of DGF.

Adding value to liver (and allograft) biopsy evaluation using a combination of multiplex quantum dot immunostaining, high-resolution whole-slide digital imaging, and automated image analysis

Various technologies including nucleic acid, protein, and metabolic array analyses of blood, liver tissue, and bile are emerging as powerful tools in the study of hepatic pathophysiology. The entire lexicon of liver disease, however, has been written using classical hematoxylin-eosin staining and light microscopic examination. The authors' goal is to develop new tools to enhance histopathologic examination of liver tissue that would enrich the information gained from liver biopsy analysis, enable quantitative analysis, and bridge the gap between various "-omics" tools and interpretation of routine liver biopsy results. This article describes the progress achieved during the past 2 years in developing multiplex quantum dot (nanoparticle) staining and combining it with high-resolution whole-slide imaging using a slide scanner equipped with filters to capture 9 distinct fluorescent signals for multiple antigens. The authors first focused on precise characterization of leukocyte subsets, but soon realized that the data generated were beyond the practical limits that could be properly evaluated, analyzed, and interpreted visually by a pathologist. Therefore, the authors collaborated with the open source FARSIGHT image analysis project (http://www.farsight-toolkit.org). FARSIGHT's goal is to develop and disseminate the next-generation toolkit of automated image analysis methods to enable quantification of molecular biomarkers on a cell-by-cell basis from multiparameter images. The resulting data can be used for histocytometric studies of the complex and dynamic tissue microenvironments that are of biomedical interest. The authors envisage that these tools will eventually be incorporated into the routine practice of surgical pathology and precipitate a revolution in the specialty.