Tackling the shortage of donor kidneys: how to use the best that we have

Normothermic ex vivo perfusion of deceased donor kidneys and its clinical potential in kidney transplantation outcomes

In recent years, normothermic machine perfusion (NMP) has emerged in conversation surrounding organ preservation and transplantation techniques with the goal of improving patient and clinical outcomes. This is in great attempt to address the rate of non-utilization and the shortage of available organs in kidney transplantation. This focus in mind, normothermic perfusion presents itself as a potential tool to mimic physiological conditions and improve current preservation methods, such as static cold storage. This review serves to improve understanding of the observed connection between the consequences of ischemia and reperfusion injury and traditional preservation techniques as well as how renal NMP may mitigate these issues. Previous studies suggest that reducing time in static cold storage methods by promoting the normothermic perfusion model results in decreased delayed graft function and post-transplant complications. This review also aims to present the immense clinical potential NMP has on future kidney transplantation success and what this means for the fields of nephrology and transplantation. While great strides have been made to evaluate normothermic perfusion's impact on kidney graft viability and transplant success, future research into unified protocol, clinically relevant biomarkers, cost-utility analysis, and use with associated therapeutic and imaging modalities is paramount.

A neural network for glomerulus classification based on histological images of kidney biopsy

Background

Computer-aided diagnosis (CAD) systems based on medical images could support physicians in the decision-making process. During the last decades, researchers have proposed CAD systems in several medical domains achieving promising results.

CAD systems play an important role in digital pathology supporting pathologists in analyzing biopsy slides by means of standardized and objective workflows. In the proposed work, we designed and tested a novel CAD system module based on image processing techniques and machine learning, whose objective was to classify the condition affecting renal corpuscles (glomeruli) between sclerotic and non-sclerotic. Such discrimination is useful for the biopsy slides evaluation performed by pathologists.

Results

We collected 26 digital slides taken from the kidneys of 19 donors with Periodic Acid-Schiff staining. Expert pathologists have conducted the slides preparation, digital acquisition and glomeruli annotations. Before setting the classifiers, we evaluated several feature extraction techniques from the annotated regions. Then, a feature reduction procedure followed by a shallow artificial neural network allowed discriminating between the glomeruli classes.

We evaluated the workflow considering an independent dataset (i.e., processing images not used in the training procedure). Ten independent runs of the training algorithm, and evaluation, allowed achieving MCC and Accuracy of 0.95 (± 0.01) and 0.99 (standard deviation < 0.00), respectively. We also obtained good precision (0.9844 ± 0.0111) and recall (0.9310 ± 0.0153).

Conclusions

Results on the test set confirm that the proposed workflow is consistent and reliable for the investigated domain, and it can support the clinical practice of discriminating the two classes of glomeruli. Analyses on misclassifications show that the involved images are usually affected by staining artefacts or present partial sections due to slice preparation and staining processes. In clinical practice, however, pathologists discard images showing such artefacts.

Preimplantation Histological Score Associates with 6-Month GFR in Recipients of Perfused, Older Kidney Grafts: Results from a Pilot Study

BACKGROUND

Biopsy-guided selection of older kidneys safely expands the organ pool, and pretransplant perfusion improves the preservation of these fragile organs. Herein, we studied morphofunctional variables associated with graft outcomes in perfused, histologically evaluated older kidneys.

METHODS

This single-center prospective cohort pilot study evaluated the relationships between preimplantation histologic scores and renal perfusion parameters during hypothermic, pulsatile, machine perfusion (MP) and assessed whether these morphofunctional parameters associated with GFR (iohexol plasma clearance) at 6 months after transplantation in 20 consecutive consenting recipients of a biopsy-guided single or dual kidney transplant from >60-year-old deceased donors.

RESULTS

The donor and recipient age was 70.4 ± 6.5 and 63.6 ± 7.9 years (p = 0.005), respectively. The kidney donor profile index (KDPI) was 93.3 ± 8.4% (>80% in 19 cases), histologic score 4.4 ± 1.4, and median (IQR) cold ischemia time 19.8 (17.8-22.8 h; >24 h in 5 cases). The 6-month GFR was 41.2 (34.9-55.7) mL/min. Vascular resistances positively correlated with global histologic score (p = 0.018) at MP start and then decreased from 0.88 ± 0.43 to 0.36 ± 0.13 mm Hg/mL/min (p < 0.001) in parallel with a three-fold renal flow increase from 24.0 ± 14.7 to 74.7 ± 31.8 mL/min (p < 0.001). Consistently, vascular resistance reductions positively correlated with global histologic score (p = 0.009, r = -0.429). Unlike KDPI or vascular resistances, histologic score was independently associated with 6-month GFR (beta standardized coefficient: -0.894, p = 0.005).

CONCLUSIONS

MP safely improves graft perfusion, particularly in kidneys with severe histologic changes that would not be considered for transplantation because of high KDPI. The preimplantation histologic score associates with the functional recovery of older kidneys even in the context of a standardized program of pulsatile perfusion.

The association of living donor source with patient and graft survival among kidney transplant recipients in the ERA-EDTA Registry - a retrospective study

In this study we aimed to compare patient and graft survival of kidney transplant recipients who received a kidney from a living‐related donor (LRD) or living‐unrelated donor (LUD). Adult patients in the ERA‐EDTA Registry who received their first kidney transplant in 1998–2017 were included. Ten‐year patient and graft survival were compared between LRD and LUD transplants using Cox regression analysis. In total, 14 370 patients received a kidney from a living donor. Of those, 9212 (64.1%) grafts were from a LRD, 5063 (35.2%) from a LUD and for 95 (0.7%), the donor type was unknown. Unadjusted five‐year risks of death and graft failure (including death as event) were lower for LRD transplants than for LUD grafts: 4.2% (95% confidence interval [CI]: 3.7–4.6) and 10.8% (95% CI: 10.1–11.5) versus 6.5% (95% CI: 5.7–7.4) and 12.2% (95% CI: 11.2–13.3), respectively. However, after adjusting for potential confounders, associations disappeared with hazard ratios of 0.99 (95% CI: 0.87–1.13) for patient survival and 1.03 (95% CI: 0.94–1.14) for graft survival. Unadjusted risk of death‐censored graft failure was similar, but after adjustment, it was higher for LUD transplants (1.19; 95% CI: 1.04–1.35). In conclusion, patient and graft survival of LRD and LUD kidney transplant recipients was similar, whereas death‐censored graft failure was higher in LUD. These findings confirm the importance of both living kidney donor types.

Kidney Transplantation From Old Deceased Donors: Impact of Uric Acid Level-A Quarter-Century of Experience in One Transplant Center

BACKGROUND

The long-term burden of higher donor age on graft function and survival after kidney transplantation remains uncertain. Because both recipient and donor characteristics have evolved and the general population age is on the increase, we looked at the causes of kidney graft outcome.

AIM

The aim of this study was to evaluate the impact of different clinical parameters on long-term outcome of older-donor kidney transplantation. This retrospective study included 345 adult patients (58 patients received kidney from donors at least 55 years old) transplanted between January 1993 and December 2005 and were followed in one center throughout the post-transplant course (median, 9.4 years). Data included recipient and donor age, cold ischemia time, delayed graft function, panel reactive antibodies, HLA mismatch, time on dialysis, graft function at different time points, uric acid level, proteinuria, immunosuppression, and biopsy-proven rejection.

RESULTS

Improvement of estimated glomerular filtration rate at 36 months after transplantation was a good prognostic factor for long-term kidney function. Higher donor age decreased the chance for improvement of kidney function by 2.8% per year of life (P = .0244). Hyperuricemia was found in 46% of the study population; estimated glomerular filtration rate less than 50 mL/min/1.72 m² was associated with hyperuricaemia. A higher uric acid level was associated with inferior kidney function in recipient of older kidneys. Graft failure occurred late (median, 6.3 years post-transplantation) in 26 (44.8%) of older-donor recipients and in 87 (30.3%) of the remaining patients.

CONCLUSIONS

Our results suggest an important association between older donor age and decreased allograft function in kidney recipients with elevated uric acid level. Recipients of older kidneys with normal uric acid level presented satisfactory outcomes.

Early Graft Loss after Kidney Transplantation: Endothelial Dysfunction of Renal Microvasculature

Decision process about the acceptance of the deceased donor kidney for transplantation might be challenging. Although histological evaluation of pretransplant donor kidney biopsy provides reliable information regarding cortical necrosis, vascular thrombosis, extensive global glomerulosclerosis, and interstitial fibrosis/tubular atrophy, only electron microscopy enables thorough and reliable insights into microvasculature changes of kidney graft. The aim of the present paper is to briefly present two cases of early kidney graft loss. In one case, the donor was exposed to long-term extracorporeal membrane oxygenation (ECMO); in the other case, the donor experienced Takotsubo cardiomyopathy. In both cases, light microscopy of pretransplant biopsy found no pathology or significant discrepancy in morphology of kidney graft, while electron microscopy revealed severe endothelial dysfunction of renal microvasculature. Our results suggest that severe injury of renal microvasculature with relatively preserved tubular epithelium may be associated with some conditions of deceased kidney donors leading to early kidney graft nonfunction and loss. Further studies are needed to determine prognostic significance of severe ultrastructural microvasculature lesions and to evaluate disease states and conditions that could be associated with severe endothelial dysfunction of kidney graft.

Long-Term Outcomes of Kidney Transplantation From Expanded-Criteria Deceased Donors: A Single-Center Experience

BACKGROUND

Organ shortage has prompted the use of expanded-criteria donors (ECDs). Our objective was to compare long-term outcomes of kidney transplants from ECDs with those from concurrent standard-criteria donors (SCDs). In addition, we evaluated variables associated with graft survival in both groups.

METHODS

We retrospectively reviewed all 617 deceased-donor kidney transplantations performed from 2005 to 2009 in our department. The population was divided according to donor status into ECD or SCD. Patients were followed until 5 years after transplantation, death, graft failure, or loss to follow-up.

RESULTS

We transplanted 150 deceased-donor kidneys from ECDs and 467 from SCDs. ECD were older, more frequently women, had a lower pre-retrieval glomerular filtration rate, and more frequently died due to cerebrovascular accident. ECD recipients were older, presented a lower proportion of black race, more frequently were on hemodialysis, and presented a higher rate of first kidney transplants. Mean glomerular filtration rate was consistently lower in the ECD group. Patient and graft survivals were lower in the ECD group, but statistical significance was present only in graft survival censored for death with a functioning graft at 3 years and graft survival noncensored for death with a functioning graft at 5 years. Younger recipient ages, longer time on dialysis, acute rejection episodes, and glomerular filtration rate at 1 year after transplantation were independent risk factors for lower graft survival.

CONCLUSIONS

Transplantation with the use of ECD kidneys provide quite satisfactory patient and graft survival rates despite their poorer long-term outcomes.

Identification of the activating cytotoxicity receptor NKG2D as a senescence marker in zero-hour kidney biopsies is indicative for clinical outcome

The definition of biological donor organ age rather than chronological age seems obvious for the establishment of a valid pre-transplant risk assessment. Therefore, we studied gene expression for candidate markers in 60 zero-hour kidney biopsies. Compared with 29 younger donors under age 55, 31 elderly donors age 55 and older had significant mRNA expression for immunoproteasome subunits (PSMB8, PSMB9 and PSMB10), HLA-DRB, and transcripts of the activating cytotoxicity receptor NKG2D. Gene expression was validated in an independent donor cohort consisting of 37 kidneys from donors 30 years and under (Group I), 75 kidneys from donors age 31-54 years (Group II) and 75 kidneys from donors age 55 and older (Group III). Significant gene induction was confirmed in kidneys from Group III for PSMB9 and PSMB10. Strikingly, transcripts of NKG2D had the significantly highest gene induction in Group III versus Group II and Group I. Similar results were obtained for CDKN2A, but not for telomere length. Both NKG2D and CDKN2A mRNA expression were significantly correlated with creatinine levels at 24 months after transplantation. Univariate regression analysis showed significant predictive power regarding graft function at 6 and 12 months for NKG2D and CDKN2A. However, only NKG2D remained significantly predictive in the multivariate model at 12 months. Thus, our results reveal novel candidate markers in aged renal allografts, which could be helpful in the assessment of organ quality.

Transplantation of Restored Kidneys From Unrelated Donors After Resection of Renal Cell Carcinoma: Results From 10 Patients

PURPOSE

To relieve the chronic shortage of donor kidneys, we conducted a prospective kidney transplantation trial using kidneys removed from 10 unrelated patients (51 to 79 years of age) who had undergone nephrectomy for small renal cell carcinoma (1.5 to 3.9 cm) of low-to-moderate complexity based on RENAL (radius, exophytic/endophytic properties, nearness of tumor to the collecting system or sinus in millimeters, anterior/posterior location relative to polar lines) nephrometry (objective description helpful for operative indication and planning).

METHODS

Donors were selected from among 15 patients who opted to undergo nephrectomy for small renal cell carcinoma. A total of 76 dialysis patients 34 to 85 years of age who agreed to undergo restored kidney transplantation were recruited as transplant candidates.

RESULTS

In stage 1 (5 cases), high-risk patients were selected without human leukocyte antigen testing, and accelerated acute rejection occurred in 4 of 5 recipients. This trial was subsequently extended with human leukocyte antigen testing, and an additional 5 patients were enrolled in stage 2. Eight recipients, including 4 recipients with a history of renal transplantation, experienced rejection; 1 patient resumed dialysis 35 months after transplantation. The most recent serum creatinine levels ranged from 1.10 to 3.19 mg/dL in the 9 recipients with functioning grafts and from 0.84 to 4.68 mg/dL in the 10 donors. No tumor recurrence was noted at 32 to 58 months after surgery in either the recipients or the donors.

CONCLUSIONS

Restored kidney transplantation using kidneys with a small renal tumor seems suitable for carefully selected high-risk recipients and, in particular, elderly kidneys can also function well. Avoiding cancer transmission, fair recipient selection, close follow-up, and a well-organized tracking system warrant further study.

Early graft loss after kidney transplantation: risk factors and consequences

Early graft loss (EGL) after kidney transplantation is a catastrophic outcome that is assumed to be more likely after the use of kidneys from suboptimal donors. We therefore examined its incidence, risk factors and consequences in our center in relation to different donor types. Of 801 recipients who received a kidney-only transplant from deceased donors, 50 (6.2%) suffered EGL within 30 days of transplantation. Significant risks factors for EGL were donation after circulatory death (DCD) (odds ratio [OR] 2.88; p = 0.006), expanded criteria donor (ECD) transplantation (OR 4.22; p = 0.010), donor age (OR 1.03; p = 0.044) and recipient past history of thrombosis (OR 4.91; p = 0.001). Recipients with EGL had 12.28 times increased risk of death within the first year, but long-term survival was worse for patients remaining on the waiting list. In comparison with patients on the waiting list but not transplanted, and with all patients on the waiting list, the risk of death after EGL decreased to baseline 4 and 23 months after transplantation, respectively. Our findings suggest that DCD and ECD transplantation are significant risk factors for EGL, which is a major risk factor for recipient death. However, long-term mortality is even greater for those remaining on the waiting list.

Coagulation profiles of unexpected DCDD donors do not indicate a role for exogenous fibrinolysis

It has been suggested that vascular stasis during cardio-circulatory arrest leads to the formation of microvascular thrombi and the viability of organs arising from donation after circulatory determination of death (DCDD) donors may be improved through the application of fibrinolytic therapy. Our aim was to comprehensively study the coagulation profiles of Maastricht category II DCDD donors in order to determine the presence of coagulation abnormalities that could benefit from fibrinolytic therapy. Whole blood from potential DCDD donors suffering out-of-hospital cardiac arrest was sampled after declaration of death in the emergency department, and rotational thromboelastomeric analysis was performed. Between July 2012 and December 2013, samples from 33 potential DCDD donors were analyzed. All patients demonstrated hyperfibrinolysis (HF), as reflected by maximum clot lysis of 98-100% in all cases, indicating that there is no role for additional fibrinolytic therapy in this setting. As well, we observed correlations between thromboelastomeric lysis parameters and maximum hepatic transaminase levels measured in potential donors and renal artery flows measured during ex situ hypothermic oxygenated machine perfusion, indicating that further studies on the utility of thromboelastometry to evaluate organ injury and perhaps even viability in unexpected DCDD may be warranted.

Can only histological evaluation determine the allocation of ECD kidneys?

INTRODUCTION

There is a recent debate on the "transplantability" of ECD (Expanded Criteria Donors) kidneys and the selection criteria used to allocate them to single or double transplantation. Remuzzi et al. have defined a protocol incorporating pre-transplant donor biopsy to guide the use of older donor organs. They allocated organs as single or double transplants on the basis of histological findings. We aim to show the pros and cons of the only histological evaluation in the allocation of ECD kidneys, to compare the different experiences in United States and Europe and thus to discuss whether this tool should be used alone or included in a comprehensive clinical and histopathological evaluation.

DISCUSSION

In the United States many Authors stated that the biopsy actually increases the percentage of kidney discarded and they raised questions about the importance of the biopsy in evaluating ECD kidneys for transplantation. On the other hand, the experiences of the majority of european transplant centers showed that allocating kidneys as single or dual transplant based on biopsy findings may achieve good graft and patient outcomes. Moreover, the experience of some centers as ours showed that kidneys allocated as DKT (Dual Kidney Transplant) on the basis of Remuzzi's score could have been suitable for single transplantation suggesting the need of an adjustment of the Remuzzi Score System. Many Authors, who are in favor of histological evaluation, actually believe that a comprehensive clinical and histopathological assessment before transplantation remains necessary. We lack precise national- or international-based selection criteria to guide clinicians. An adjustment of the Remuzzi Score System could be taken into consideration such as narrowing the indication for DKT from those ECD kidneys with higher scores and including the histological evaluation in a multifactor score.

Proposal of categorization of expanded criteria donors in renal transplantation

INTRODUCTION

Transplantation of renal allografts that have been procured from expanded criteria donors (ECD) have prevailed in an attempt to expand the donor pool. Even though ECD is an acceptable source of donors, the wide range of age along with the presence or not of risk factors necessitates further categorization. The aim of this study was to analyze the allograft and recipient survival of the ECD renal grafts and to propose an ECD categorization model.

PATIENTS AND METHODS

We reviewed the medical records of renal transplant recipients from January 2002 to July 2012, who received renal allografts from expanded and standard criteria donors (SCD) without risk factors such as hypertension, cerebrovascular disease or impaired renal function.

RESULTS

During the study period, 310 renal transplantations were performed in our Transplant Unit, of which 86 and 114 renal grafts were procured from ECD and SCD respectively. ECD renal graft survival the first, third and fifth year was 92%, 82% and 70% while respective recipient survival was 95%, 87% and 82%. Comparison with the control group of SCD showed that ECD renal graft survival after the third post-transplant year was significantly inferior (P < .0001). Donor age was a considerable prognostic factor of long-term renal graft function. Serum creatinine of ECD grafts was the first and third year 1.86 ± 0.6 mg/dL and 1.91 ± 0.8 mg/dL, respectively, showing significant difference to that of SCD grafts (P < .0001). Further categorization of ECD showed that renal allografts procured from donors above 60 years old without risk factors had better renal graft survival and function compared to grafts procured from donors aged 50-59 with 2 or 3 risk factors.

CONCLUSIONS

Renal transplantation from ECD offers acceptable graft survival rates, however they are inferior compared to renal grafts from optimal kidney donors. ECD kidney grafts have to be categorized, taking into consideration the independent risk factors.

Influence of steroid maintenance on the outcomes in deceased donor kidney transplant recipients experiencing delayed graft function

Delayed graft function (DGF) is a risk factor for poor long-term graft and patient survival after kidney transplantation. The aim of our study was to explore the beneficial effect of steroid maintenance on outcomes in deceased donor kidney (DDK) transplant recipients with DGF. Using organ procurement and transplant network/United network of organ sharing (OPTN/UNOS) database, we identified adult patients who developed DGF following DDK transplantation performed between January 2000 and December 2008. They received induction with rabbit antithymocyte globulin (r-ATG), alemtuzumab or an interluekin-2 receptor blocker (IL-2B) and were discharged on a calcineurin inhibitor (CNI)/mycophenolate (MMF) based immunosuppression with or without steroids. Adjusted graft and patient survivals were compared between steroid versus no steroid groups for each induction modality. Median follow-up was 29.6 months for the 10,058 patients who developed DGF. There were 5624 patients in r-ATG (steroid, n = 4569, no steroid, n = 1055), 819 in alemtuzumab (steroid, n = 301, no steroid, n = 518) and 3615 in IL-2B (steroid, n = 3380, no steroid, n = 235) groups. Adjusted graft survivals were similar for steroid versus no-steroid groups in patients who received r-ATG (HR: 0.98, 95% CI 0.85-1.13, P = 0.75), alemtuzumab (HR 0.88, 95% CI 0.65-1.19, P = 0.41), and IL-2B (HR 1.01, 95%CI 0.78-1.30, P = 0.96) inductions. The adjusted patient survivals were also similar in r-ATG (HR: 1.19, 95% CI 0.96-1.46, P = 0.19), alemtuzumab (HR: 0.89, 95% CI: 0.57-1.39, P = 0.96), and IL-2R (HR: 1.07, 95% CI: 0.77-1.49, P = 0.96) groups. Our study failed to show any significant graft or patient survival benefits associated with steroid addition to CNI/MMF regimen in DDK recipients with DGF. This may be related to the early immunogenic and non-immunogenic allograft damage from DGF with long-term consequences that are unaltered by steroids.

Optimizing utilization of kidneys from deceased donors over 60 years: five-year outcomes after implementation of a combined clinical and histological allocation algorithm

This 5 year observational multicentre study conducted in the Nord Italian Transplant programme area evaluated outcomes in patients receiving kidneys from donors over 60 years allocated according to a combined clinical and histological algorithm. Low-risk donors 60-69 years without risk factors were allocated to single kidney transplant (LR-SKT) based on clinical criteria. Biopsy was performed in donors over 70 years or 60-69 years with risk factors, allocated to Single (HR-SKT) or Dual kidney transplant (HR-DKT) according to the severity of histological damage. Forty HR-DKTs, 41 HR-SKTs and 234 LR-SKTs were evaluated. Baseline differences generally reflected stratification and allocation criteria. Patient and graft (death censored) survival were 90% and 92% for HR-DKT, 85% and 89% for HR-SKT, 88% and 87% for LR-SKT. The algorithm appeared user-friendly in daily practice and was safe and efficient, as demonstrated by satisfactory outcomes in all groups at 5 years. Clinical criteria performed well in low-risk donors. The excellent outcomes observed in DKTs call for fine-tuning of cut-off scores for allocation to DKT or SKT in high-risk patients.

Expanded Criteria Donors in Kidney Transplantation: The Role of Older Donors in a Setting of Older Recipients

Kidney transplantation (KT) is the therapy of choice for end-stage renal disease (ESRD). The ESRD population is aging and so are patients waiting for KT. New strategies have been made for increasing the donor and recipient pools, and as a consequence kidneys from older donors or donors with significant comorbidities, the so-called “expanded criteria donor” (ECD) kidneys, are used for transplantation. Although good outcomes have been achieved from ECD, several issues are still waiting for clarification and need to be discussed. The concept of age matching is accepted as a method to ameliorate utilization of these allografts, but an optimal and widely accepted strategy is still not defined. The development of machine perfusion and the dual kidney transplantation are techniques which further improve the outcome of transplants from ECD, but the described experiences are scarce or coming from small single institutional reports. Also due to age-related immune dysfunction and associated comorbidities, the elderly recipients are more susceptible to immunosuppression related complications (e.g., infections and malignancy), although a widely accepted and validated immunosuppressive regimen is still lacking. In this paper, we review the issues related to KT employing allografts from marginal donors with a particular interest for the elderly patients.

Predonation quality of life and early postdonation safety of older living renal donors in China

BACKGROUND

Studies on the safety of older living renal donors are lacking in China.

METHODS

We observed 142 consecutive living renal donors before and early after (7 days) the operation. There were no prisoners used as donors or recipients. Subjects were divided into 2 groups: older than 50 years of age (n = 40) or younger age (n = 102). We compared differences in early safety between the 2 groups.

RESULTS

There were no significant differences in 8 aspects of the predonation quality of life using the SF-36 questionnaire, except for physical function (P < .001). Zero hour biopsies performed on 52 kidneys showed 15 to display abnormal renal tissues (28.85%), which was significantly greater among the older age group (P = .034). The perioperative indexes were similar between the 2 groups; however, the hospital stay was longer in the older group (P = .034). Compared with the younger group, the older group generally showed a lower creatinine clearance (CCr; P < .001), higher cystatin c (P = .006), and similar serum creatinine (Scr) preoperatively, conditions that persisted at 7 days postoperatively. Although the increased Scr and reduced CCr were present in all donors, the changes in Scr and CCr were similar between the 2 groups. Differences in urinary micro-albumin and proteinuria before and after operation were not significantly different for both groups.

CONCLUSIONS

Increased use of older living kidney donors in China may be a safe strategy to meet the demand for transplantation. However, long-term outcomes need further follow-up.

The relationship of donor source and age on short- and long-term allograft survival in pediatric renal transplantation

Limited pediatric data on allograft survival from advanced aged kidney donors exist. To determine the influence of donor source and age on allograft survival in pediatric renal transplant recipients, we analyzed the OPTN database. Allograft survival for 7291 pediatric renal transplants was evaluated. Up to five yr post-transplantation, graft survival was higher for LD vs. DD recipients. At seven yr, allograft survival was 71% in 18-54 yr-old LD recipients, 59.1% in >or=55 yr-old LD, and 45.1% in >or=50 yr-old DD recipients. An approximate 35% improvement in allograft survival in 18-54 yr-old LD recipients was observed. Multivariate results showed that recipients of LD 35-49 (aRR 0.66, 95% CI 0.55-0.80) and LD 50-54 (aRR 0.65, 95% CI 0.45-0.94) have a graft survival advantage over the ideal DD. In LD >or=55 yr, no improvement in graft survival was observed when compared with the 18-34 yr-old DD. In summary, we observed in a pediatric population, <55 yr-old LD kidneys afford improved long-term allograft survival when compared with DD kidney recipients. Increasing awareness of the long-term graft survival advantage for children receiving an LD kidney, even from older donors, should be a priority.

Genetic prediction of renal transplant outcome

PURPOSE OF REVIEW

In the present study, we reviewed recent publications regarding potential genetic predictors of transplant outcome, including acute rejection, metabolism of immunosuppressive medications, long-term transplant outcome, and posttransplant complications.

RECENT FINDINGS

Recent studies are based on the candidate gene analysis; specifically, cytokine genes and innate immune response molecules present popular targets for studies of acute rejection and long-term outcome. Pharmacogenomic studies are mostly focused on the genes of drug targets or the corresponding enzymes metabolizing the drug. Posttransplant complications (i.e. infections, diabetes, and malignancies) are associated with a variety of genes of different pathways. Most of the studies are based on just recipient, but not donor, genotype analysis. Positive results are balanced by reports of no association when evaluating the same genetic polymorphisms. Some of the reports might be affected by insufficient study design, including small sample size, lack of adjustment for potential confounders, and multiple comparisons.

SUMMARY

The field remains controversial because of differences in populations, study design, and statistical methods. Studies are based on candidate gene analysis; however, genome-wide association studies are lacking. Future research should be directed at better designed studies, larger sample size, evaluating both recipients and donors, and implementation of genome-wide association studies.

Renal transplantation in the elderly

Elderly patients are increasingly being considered for kidney transplantation due to a global explosion of the aging population with end-stage renal disease (ESRD). However, mounting scarcity of available organs for transplant has led to a wider disparity between organ supply and demand. Consequently, the criteria for accepting kidneys for transplantation have been extended in an attempt to allow the use of organs from elderly donors or those with significant co-morbidities, so-called "expanded criteria donor" (ECD) kidneys. Excellent outcomes have been achieved from ECD kidneys with appropriate donor and recipient profiling and selection. With increasing recovery efforts directed at older donors, the concept of age-matching is becoming more accepted as a method of optimizing utilization of organs in elderly donors and recipients. Utilization of pulsatile perfusion has further improved ECD outcomes and helped the decision-making process for the UNOS (United Network for Organ Sharing) offer. However, age-related immune dysfunction and associated co-morbidities make the elderly transplant recipients ever more susceptible to complications associated with immunosuppressive agents. Consequently, the elderly population is at a higher risk to develop infections and malignancy in the post-transplant period notwithstanding improved transplant outcomes. Appropriate immunosuppressive agents and dosages should be selected to minimize adverse events while reducing the risk of acute rejections and maximizing patient and renal allograft survival.

Successful transplantation of kidneys from a donor with myoglobinuric acute renal failure

The shortage of donor organs is reflected in the growing number of patients on the waiting list for kidney transplantation worldwide. It seems to be sensible to expand the scarce donor pool by the cautious use of extended donor criteria. Kidneys from a 21-year-old deceased donor road traffic accident victim who suffered acute renal failure (ARF) due to myolysis were transplanted. Both transplantations were successful after an initial period of delayed graft function. Therefore, kidneys from deceased donors with ARF should not be excluded for transplantation in general.

Long-term outcome of renal transplantation from older donors

BACKGROUND

Long-term survival of kidney grafts from older donors is inferior to that of grafts from younger donors. We sought to determine whether selecting older kidneys according to their histologic characteristics before implantation would positively influence long-term outcome.

METHODS

In a prospective cohort study, we assessed outcomes among 62 patients who received one or two histologically evaluated kidneys from donors older than 60 years of age. These outcomes were compared with outcomes among 248 matched recipients of single kidney grafts that had not been histologically evaluated and were either from donors 60 years of age or younger (124 positive-reference recipients who, according to available data, were expected to have an optimal outcome) or from those older than 60 years (124 negative-reference recipients, expected to have a worse outcome). The primary end point was graft survival.

RESULTS

During a median period of 23 months, 4 recipients (6 percent) of histologically evaluated kidneys progressed to dialysis, as compared with 7 positive-reference recipients (6 percent) and 29 negative-reference recipients (23 percent). Graft survival in recipients of histologically evaluated kidneys did not differ significantly from that of grafts in positive-reference recipients but was superior to that of grafts in negative-reference recipients (hazard ratio for graft failure in the negative-reference recipients relative to the recipients of histologically evaluated kidneys, 3.68; 95 percent confidence interval, 1.29 to 10.52; P=0.02). The performance of preimplantation histologic evaluation predicted better survival both in the whole study group (P=0.02) and among recipients of kidneys from older donors (P=0.01).

CONCLUSIONS

The long-term survival of single or dual kidney grafts from donors older than 60 years of age is excellent, provided that the grafts are evaluated histologically before implantation. This approach may help to expand the donor-organ pool for kidney transplantation.

Demographic analysis and outcome features in a transplant outpatient clinic

AIM

This retrospective report analyzed the demographic features of kidney transplant outpatients grafted in Turkey and in different regions of the world.

METHODS

The patients were divided into 4 groups: Every cohort was subgrouped as either receiving a cadaveric (CT) or a live donor transplant (LT) performed in our institute (ICT, n = 147, ILT, n = 304), other institutions in Turkey (TCT, n = 16, TLT, n = 86), or in a foreign country (FCT, n = 66, FLT, n = 154).

RESULTS

Among the patients with functional grafts, FLT transplantations, of which the vast majority were paid transplantations, constituted the second largest group (n = 105) following ILT (n = 214). In the ILT group, 5- and 10-year graft survival rates were 76% and 50%, respectively, and patient survival rates were 88% and 78%, respectively. Considering the FLT group, 5- and 10-year graft survival figures were 70% and 42%, respectively, while patient survival rates in these periods were 81% and 69%, respectively. Patients with paid donor transplantations were characterized by a high risk of unconventional infectious complications in the early period, while midterm patient and graft survival was somewhat better than expected considering the high rate of complications in the early period.

CONCLUSIONS

Paid organ transplantation should be discouraged. Organ donation should be stimulated by every means to avoid potentially fatal unconventional infections after transplantation from paid donors. If patients receive a paid transplant, however, they should be closely followed for these complications, since, if they survive the early period the midterm and long-term outcomes are quite reasonable.

Cyclosporine Prolongs Delayed Graft Function in Kidney Transplantation: Are Rabbit Anti-Human Thymocyte Globulins the Answer?

BACKGROUND

Cyclosporine (CsA) nephrotoxicity may prolong duration of anuria in renal transplant patients with delayed graft function (DGF). Thus, many Transplant Centers tend to delay CsA treatment in order to accelerate renal function recovery.

METHODS

In this single-center, retrospective analysis we compared the outcomes of 40 renal transplant patients with DGF given a CsA-based (n = 17) regimen since the day of transplant or a CsA-sparing regimen (n = 23) based on early treatment with rabbit anti-human thymocyte globulin (RATG) and delayed CsA administration. We studied all patients with DGF who received a first or second graft at the Bergamo Transplant Center from January 1992 to March 2000.

RESULTS

Patients given RATG as compared to those on CsA had significantly shorter duration of anuria (11.0 +/- 5.6 vs. 19.6 +/- 8.9 days; p < 0.005) and of initial hospitalization (17.4 +/- 4.3 vs. 27.4 +/- 10.4 days; p < 0.001). Throughout the whole study period, 4 patients on RATG as compared to 6 on CsA had an acute rejection episode (p > 0.05). However, no patient on RATG as compared to 4 on CsA had an acute rejection during the anuria period (p < 0.05). Costs including hospitalization, dialysis treatment and study drugs were significantly lower in RATG than in CsA patients (EUR 29,944 +/- 7,281 vs. 36,795 +/- 13,656; p < 0.05).

CONCLUSIONS

In renal transplant patients with DGF, early RATG treatment with delayed CsA administration accelerated renal function recovery and patient discharge, prevented occult rejections throughout the anuria period and significantly decreased the treatment costs.

Delayed graft function in kidney transplantation

Delayed graft function is a form of acute renal failure resulting in post-transplantation oliguria, increased allograft immunogenicity and risk of acute rejection episodes, and decreased long-term survival. Factors related to the donor and prerenal, renal, or postrenal transplant factors related to the recipient can contribute to this condition. From experimental studies, we have learnt that both ischaemia and reinstitution of blood flow in ischaemically damaged kidneys after hypothermic preservation activate a complex sequence of events that sustain renal injury and play a pivotal part in the development of delayed graft function. Elucidation of the pathophysiology of renal ischaemia and reperfusion injury has contributed to the development of strategies to decrease the rate of delayed graft function, focusing on donor management, organ procurement and preservation techniques, recipient fluid management, and pharmacological agents (vasodilators, antioxidants, anti-inflammatory agents). Several new drugs show promise in animal studies in preventing or ameliorating ischaemia-reperfusion injury and possibly delayed graft function, but definitive clinical trials are lacking. The goal of monotherapy for the prevention or treatment of is perhaps unattainable, and multidrug approaches or single drug targeting multiple signals will be the next step to reduce post-transplantation injury and delayed graft function.