An old virtue to improve senior programs

The combinatorial effect of age and biological sex on alloimmunity and transplantation outcome

Both age and biological sex affect transplantation outcomes. We have recently shown in a large volume clinical analysis utilizing the SRTR data that graft survival is inferior in young female kidney transplant recipients. In this multi-factorial analysis, older female recipients presented with a trend towards improved transplant outcomes compared to both young female recipients and male recipients of any age. Those data supported by reports of those of others suggest that sex and age impact alloimmune responses both, individually and synergistically. Biological sex and hormone levels change throughout a lifetime with recognized effects on longevity in addition to an impact on the development and course of several disease preconditions. Detailed mechanisms of those sex and age-specific aspects have thus far been studied outside of transplantation. Effects on alloimmunity are largely unknown. Moreover, the combinatorial impact that both, biological sex and age have on transplant outcomes is not understood. Here, we summarize available data that analyze how age in combination with biological sex may shape alloimmune responses and affect transplant outcomes.

Retransplanting a previously transplanted kidney: A safe strategy in times of organ shortage?

BACKGROUND

The shortage of organs for transplantation remains a global problem. The retransplantation of a previously transplanted kidney might be a possibility to expand the pool of donors. We provide our experience with the successful reuse of transplanted kidneys in the Eurotransplant region.

METHODS

A query in the Eurotransplant database was performed between January 1, 1995 and December 31, 2015, to find kidney donors who themselves had previously received a kidney graft.

RESULTS

Nine out of a total of 68,554 allocated kidneys had previously been transplanted. Four of these kidneys were transplanted once again. The mean interval between the first transplant and retransplantation was 1689±1682 days (SD; range 55-5,333 days). At the time of the first transplantation the mean serum creatinine of the donors was 1.0 mg/dl (.6-1.3 mg/dl) and at the second transplantation 1.4 mg/dl (.8-1.5 mg/dl). The mean graft survival in the first recipient was 50 months (2-110 months) and in the second recipient 111 months (40-215 months).

CONCLUSION

Transplantation of a previously transplanted kidney may successfully be performed with well-preserved graft function and long-term graft survival, even if the first transplantation was performed a long time ago. Such organs should be considered even for younger recipients in carefully selected cases.

Two decades of the Eurotransplant Senior Program: the gender gap in mortality impacts patient survival after kidney transplantation

BACKGROUND

Long-term outcomes of the Eurotransplant Senior Program (ESP) are urgently needed to improve selection criteria and allocation policies in the elderly.

METHODS

We analysed patient and allograft outcomes of 244 ESP-kidney transplant recipients (KTRs) between 1999 and 2019 and assessed quality of living compared with 82 ESP-waitlisted dialysis patients using standardized short form-8.

RESULTS

We observed 1-, 5- and 10-year patient survival of 91.7, 66.3 and 38.0%, respectively. Mortality risk factors included male gender (P = 0.006) and T-cell-mediated rejection (P < 0.001). Median patient survival of male ESP-KTRs was 80 versus 131 months for female ESP-KTRs (P = 0.006). 1-, 5- and 10-year death-censored allograft survival was 93.3, 82.6 and 70.4%. Risk factors included high body mass index (P < 0.001) and T-cell-mediated rejection (P < 0.001). After re-initiation of dialysis median patient survival was 58 months. Change of estimated glomerular filtration rate showed a mean decline of 2.3 and 6.8 mL/min at 5 and 10 years. Median physical and mental component scores of ESP-KTRs were 40.2 and 48.3, significantly higher compared with dialysis patients (P < 0.05). Of ESP-KTRs, 97.5% who underwent transplantation would again do so.

CONCLUSIONS

Long-term outcomes of ESP-KTRs ultimately support the effectiveness of an age-matched allocation system. Our data suggest that the survival advantage of women is maintained after kidney transplantation and calls for gender-specific care.

Impact of HLA compatibility in recipients of kidneys from expanded criteria donors: A Collaborative Transplant Study Report

Due to a widespread organ shortage, the use of expanded criteria donors (ECDs) in kidney transplantation has increased persistently, reaching approximately 40% in recent years. Whether human leucocyte antigen (HLA) matching between donor and recipient should be part of allocation algorithms in transplantation of ECD kidneys, and especially of ECD kidneys from ≥70-year-old donors, is still in question. To this end, 135,529 kidney transplantations performed between 2000 and 2017 and reported to the Collaborative Transplant Study were analysed and the impact of HLA-A+B+DR mismatches on death-censored graft and patient survival as well as on rejection episodes was investigated. Results were stratified according to donor status (standard criteria donor (SCD) versus ECD) and age of ECD. HLA incompatibility increased the five-year death-censored graft failure risk similarly strong in recipients of ECD and SCD transplants (hazard ratio (HR) per HLA mismatch 1.078 and 1.075, respectively; p < .001 for both). Its impact on rejection treatments during the first post-transplant year was also significant but slightly weaker for recipients of ECD transplants (risk ratio (RR) per HLA mismatch 1.10 for ECD transplants and 1.13 for SCD transplants; p < .001 for both). Mortality increased gradually from zero to six HLA mismatches in recipients of SCD transplants, whereas for ECD transplants a significant increase was notable only from zero to more than zero mismatches. A significant but slightly less pronounced impact of HLA incompatibility on graft failure was observed in transplants from ≥70- compared with <70-year-old ECDs (HR per mismatch 1.047 and 1.093; p = .009 and < 0.001, respectively). The influence of HLA mismatches on rejection treatments was the same for both ECD age groups (RR = 1.10, p < .001 and p = .004, respectively). Our data indicate that HLA matching should be part of allocation algorithms not only in transplantation of kidneys from SCDs but also from ECDs.

Impact of Combinations of Donor and Recipient Ages and Other Factors on Kidney Graft Outcomes

As the availability of kidneys for transplantation continues to be outpaced by its growing demand, there has been an increasing utilization of older deceased donors in the last decades. Considering that definition of factors that influence deceased donor kidney transplant outcomes is important for allocation policies, as well as for individualization of post-transplant care, the purpose of this study was determine the risks for death censored graft survival and for patient survival conferred by older age of the donor in the context of the age of the recipient and of risk factors for graft and/or patient survival. The investigation was conducted in a single-center cohort of 5,359 consecutive first kidney transplants with adult deceased donors performed on non-prioritized adult recipients from January 1, 2002, to December 31, 2017. Death censored graft survival and patient survival were lower in older donors, whereas graft survival was higher and patient survival was lower in old recipients. The analyses of combinations of donor and recipient ages showed that death censored graft survival was lower in younger recipients in transplants from 18 to 59-year old donors, with standard or extended criteria, but no difference in graft survival was observed between younger and older recipients when the donor was ≥ 60-year old. Patient survival was higher in younger recipients in transplants with younger or older donors. Two to six HLA-A,B,DR mismatches, when compared to 0-1 MM, conferred risk for death-censored graft survival only in transplants from younger donors to younger recipients. Pre-transplant diabetes conferred risk for patient survival only in 50–59-year old recipients, irrespectively, of the age of the donor. Time on dialysis ≥ 10 years was a risk factor for patient survival in transplants with all donor-recipient age combinations, except in recipients with ≥ 60 years that received a kidney from an 18–49-year old donor. In conclusion, the results obtained in this study underline the importance of analyzing the impact of the age of the donor taking into consideration different scenarios.

Association of Kidney Donor Risk Index with the Outcome after Kidney Transplantation in the Eurotransplant Senior Program

Background

We evaluated the Kidney Donor Risk Index (KDRI) scoring system for kidney transplantation in the Eurotransplant Senior Program (ESP) that allocates kidneys from older donors to older recipients (≥65 years).

Material/Methods

We retrospectively analyzed data of 37 kidney transplant recipients and 36 kidney donors who participated in kidney transplantation program according to the ESP at our center from January 2004 until December 2013.

Results

Mean recipient and donor age was 67.9±2.6 and 70.5±4.0 years respectively. The mean KDRI score was 1.7±0.27. Uncensored graft survival after 1 year and 5 years was 64.2% and 53.7% respectively. Subgroup analysis showed that in kidney transplantation with KDRI >1.83, graft survival was significantly reduced compared to lower KDRI subgroups. KDRI was significantly correlated with serum creatinine level at discharge (r=0.4).

Conclusions

ESP kidneys represent a group of high-risk grafts with high KDRI scores. Higher KDRI scores in ESP kidneys was associated with reduced postoperative short-term and long-term graft outcomes. KDRI might be useful in decision-making for selecting donors for ESP kidney transplantation.

Access to kidney transplantation in European adults aged 75-84 years and related outcomes: an analysis of the European Renal Association-European Dialysis and Transplant Association Registry

To what extent access to, and allocation of kidney transplants and survival outcomes in patients aged ≥75 years have changed over time in Europe is unclear. We included patients aged ≥75-84 years (termed older adults) receiving renal replacement therapy in thirteen European countries between 2005 and 2014. Country differences and time trends in access to, and allocation of kidney transplants were examined. Survival outcomes were determined by Cox regression analyses. Between 2005 and 2014, 1392 older adult patients received 1406 transplants. Access to kidney transplantation varied from ~0% (Slovenia, Greece and Denmark) to ~4% (Norway and various Spanish regions) of all older adult dialysis patients, and overall increased from 0.3% (2005) to 0.9% (2014). Allocation of kidney transplants to older adults overall increased from 0.8% (2005) to 3.2% (2014). Seven-year unadjusted patient and graft survival probabilities were 49.1% (95% confidence interval, 95% CI: 43.6; 54.4) and 41.7% (95% CI: 36.5; 46.8), respectively, with a temporal trend towards improved survival outcomes. In conclusion, in the European dialysis population aged ≥75-84 years access to kidney transplantation is low, and allocation of kidney transplants remains a rare event. Though both are increasing with time and vary considerably between countries. The trend towards improved survival outcomes is encouraging. This information can aid informed decision-making regarding treatment options.

Mortality in Elderly Waiting-List Patients Versus Age-Matched Kidney Transplant Recipients: Where is the Risk?

The number of elderly patients on the waiting list (WL) for kidney transplantation (KT) has risen significantly in recent years. Because KT offers a better survival than dialysis therapy, even in the elderly, candidates for KT should be selected carefully, particularly in older waitlisted patients. Identification of risk factors for death in WL patients and prediction of both perioperative risk and long-term post-transplant mortality are crucial for the proper allocation of organs and the clinical management of these patients in order to decrease mortality, both while on the WL and after KT. In this review, we examine the clinical results in studies concerning: a) risk factors for mortality in WL patients and KT recipients; 2) the benefits and risks of performing KT in the elderly, comparing survival between patients on the WL and KT recipients; and 3) clinical tools that should be used to assess the perioperative risk of mortality and predict long-term post-transplant survival. The acknowledgment of these concerns could contribute to better management of high-risk patients and prophylactic interventions to prolong survival in this particular population, provided a higher mortality is assumed.

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.

Kidney and liver transplantation in the elderly

BACKGROUND

Transplant surgery is facing a shortage of deceased donor organs. In response, the criteria for organ donation have been extended, and an increasing number of organs from older donors are being used. For recipients, the benefits of transplantation are great, and the growing ageing population has led to increasing numbers of elderly patients being accepted for transplantation.

METHODS

The literature was reviewed to investigate the impact of age of donors and recipients in abdominal organ transplantation, and to highlight aspects of the fine balance in donor and recipient selection and screening, as well as allocation policies fair to young and old alike.

RESULTS

Overall, kidney and liver transplantation from older deceased donors have good outcomes, but are not as good as those from younger donors. Careful donor selection based on risk indices, and potentially biomarkers, special allocation schemes to match elderly donors with elderly recipients, and vigorous recipient selection, allows good outcomes with increasing age of both donors and recipients. The results of live kidney donation have been excellent for donor and recipient, and there is a trend towards inclusion of older donors. Future strategies, including personalized immunosuppression for older recipients as well as machine preservation and reconditioning of donor organs, are promising ways to improve the outcome of transplantation between older donors and older recipients.

CONCLUSION

Kidney and liver transplantation in the elderly is a clinical reality. Outcomes are good, but can be optimized by using strategies that modify donor risk factors and recipient co-morbidities, and personalized approaches to organ allocation and immunosuppression.

Transplanting the elderly: Balancing aging with histocompatibility

Across the world, the proportions of senior citizens (i.e. those ≥65years) increase rapidly and are predicted to constitute over 25% of the general population by 2050. In 2012 already 48% of the population with end stage renal disease (ESRD) was aged 65years or older. Transplantation is considered the preferred treatment option for ESRD offering survival advantage over long-term dialysis in the majority of patients. Indeed, acceptable outcomes have been documented for selected patients over the age of 70years or even cases over 80years. The reality of organ scarcity and prolonged waiting times for a deceased donor kidney transplantation, however, indicate that at best 50% of the selected elderly may have realistic expectations to receive a timely transplant offer. By choice or medical selection, access to transplantation also decreases with increasing age. In order to expedite the chance for elderly to receive a kidney transplant dedicated allocation systems have been developed. These allocation systems, like the Eurotransplant Senior Program (ESP), support preferential local allocation of kidneys from older donors to older patients in order to match recipient and graft life while disregarding histocompatibility for HLA antigens. The consequence has been more acute rejection episodes and an increase in immunosuppressive load. In the elderly, the most common cause of graft loss is death with functioning graft and death from infectious diseases is one of the dominant causes. The Eurotransplant Senior DR-compatible Program (ESDP) was designed to further improve the perspective of successful transplantation in the elderly in terms of life and quality of life by re-introducing matching criteria for HLA-DR in the old-for-old algorithm.

Rates of renal transplantations in the elderly-data from Europe and the US

The demography in most part of the world is changing with an increasing proportion of elderly persons. This is expected to reflect demography of patients accepted for renal replacement therapy both in the form of dialysis and transplantation. Based on this, the intention of the present review is to collect and describe available data on rates of transplantation with focus on the elderly patients in both Europe and the US. Data were collected from available sources including activity reports from national and supranational registries on uremia, organ procurement, waiting lists, and transplantations. Since 1990 both absolute numbers and proportions of elderly patients starting renal replacement therapy have increased dramatically in both Europe and the US. Although the pattern of changes is similar in Europe and the US, the incidence and prevalence rates for renal replacement therapy in the elderly are 3-4 times higher in the US. In the same period, the rates of renal transplantations in the elderly patient group have increased in both Europe and the US with increased access to the waiting list and to transplantation. Data from the United States Renal Data System on incidence of transplantation document a substantial increase in proportion of elderly transplant recipients (65+ years) from 4.2% in 1990 to 17.2% in 2012 and an increase in proportion of prevalent elderly renal transplant patients from 3.8% in 1992 to 23.3% in 2012. Similar changes have been seen in Europe. Due to these alterations in the demography of the transplant patients in both Europe and the US it is concluded that the elderly transplant patient from being a rare patient has now become a common patient necessitating increased focus on this group in order to optimize treatment results.

Pharmacokinetics and pharmacodynamics of immunosuppressive drugs in elderly kidney transplant recipients

Elderly patients are a fast growing population among transplant recipients over the past decades. Both the innate and adaptive immune reactivity decrease with age, which is believed to contribute to the decreased incidence of acute rejection and increased infectious death rate in elderly transplant recipients. In contrast to recipient age, donor age is associated with a higher incidence of acute rejection. Pharmacokinetic studies in renal transplant recipients show that CNI troughs are >5% higher in elderly compared to younger patients given the same dose normalized by body weight. This may impact the starting dose of tacrolimus and cyclosporine. Possibly in elderly patients the intracellular (in lymphocyte) concentrations are relatively high in relation to the whole blood concentration, resulting in a stronger pharmacodynamic effect at the same whole blood trough concentration. For cyclosporine this has been shown, but it is not clear if the same is true for other immunosuppressive drugs. Pharmacodynamic studies have compared the inhibition of target enzymes, or more downstream effects of immunosuppressive drugs, in younger and older patients. Measurement of nuclear factor of activated T-cell (NFAT)-regulated gene expression (RGE), a pharmacodynamic read-out of CNI, is a promising biomarker of immunosuppression. Low levels of NFAT RGE are associated with increased risk of infection and non-melanoma skin cancer in elderly patients. Clinical trials to evaluate the safety and efficacy of immunosuppression regimens in this specific patient population, which is underrepresented in published trials, are lacking. More studies in elderly patients are needed to investigate the impact of age on the pharmacokinetics or pharmacodynamics of immunosuppressive drugs, and to decide on the optimal regimen and target levels for elderly transplant recipients.

Induction with interleukin-2 antagonist for transplantation of kidneys from older deceased donors: an observational study

Background

The most important limiting factor in kidney transplantation is the scarcity of donor organs. Consequently, there is an increased use worldwide of kidneys from older deceased donors. High donor age is a known risk factor for acute cellular rejection and premature graft failure, and the optimal immunosuppressive regimen in these circumstances remains to be established.

Methods

We investigated whether induction treatment with an interleukin 2 (IL-2) receptor antagonist improves graft survival and reduces rejection episodes in recipients of kidneys from deceased donors aged ≥ 60 years. Data were retrieved for all recipients transplanted at our center from 2004 to 2009 with a kidney from a deceased donor aged > 60 years. The outcome was compared between recipients treated with (IL-2 plus) or without (IL-2 minus) an IL-2 receptor antagonist. All recipients received a calcineurin inhibitor, steroids and mycophenolate.

Results

A total of 232 first-transplant recipients were included (IL-2 plus = 149, IL-2 minus = 83). IL-2 minus was associated with increased risk of early acute rejection (OR 2.42; 95% CI 1.25 to 4.68, P = 0.009) and steroid-resistant rejection (OR 8.04; 2.77 to 23.25, P< 0.001). IL-2 plus patients had superior two-year estimated uncensored (87% versus 70%, P = 0.001) and death-censored (95% versus 79%, P< 0.001) graft survival.

Conclusions

Induction treatment with IL-2 receptor antagonist was associated with a reduction in acute rejection episodes and improved two-year graft survival in patients transplanted with kidneys from older deceased donors.

New insights on molecular mechanisms of renal aging

Long-term transplant outcome is importantly influenced by the age of the organ donor. The mechanisms how age carries out its pathophysiological impact on graft survival are still not understood. One major contributing factor for the observed poor performance of old donor kidneys seems in particular the age-related loss in renal regenerative capacity. In this review, we will summarize recent findings about the molecular basis of renal aging with specific focus on the potential role of somatic cellular senescence and mitochondrial aging in renal transplant outcome.

Long-term results of biopsy-guided selection and allocation of kidneys from older donors in older recipients

In our old-for-old program, we discard or allocate older extended criteria donor kidneys to single (SKT) or dual kidney transplantation (DKT) depending on histological Remuzzi's score in recipients older than 60 years. Here, we analyze the long-term results of this program and try to identify independent predictors of patient and graft survival. Between December 1996 and January 2008, we performed 115 SKT and 88 DKT. Discard rate was 15%. Acute rejection incidence was higher in SKT than in DKT (22.6% vs. 11.4%, p = 0.04). Renal function was better in DKT than in SKT up to 5 years after transplantation. Surgical complications were frequent in DKT. Ten-year cumulative graft survival was significantly lower in the SKT group (31% vs. 53%, p = 0.03). In SKT, histological score 4 provided similar graft survival than 3 or less, whereas in DKT score 4, 5 or 6 displayed similar outcome. Finally, independent predictors of graft survival were history of major adverse cardiac event and 1-year serum creatinine, rather than SKT or DKT. In conclusion, this biopsy-guided old-for-old strategy resulted in acceptable long-term graft survival. Our results suggest that DKT should be considered for scores of 5 or 6 only.

Renal transplantation is also an option for patients over 70

BACKGROUND

Kidney transplantation is generally regarded as the best treatment option for patients with end-stage renal disease. Because of an increase in the elderly population, the number of elderly patients with end-stage renal disease is expected to increase. The scope of this paper is to present existing knowledge about the survival after kidney transplantation of patients over 70 years of age at the time of transplantation.

MATERIAL AND METHODS

The paper is based on existing literature retrieved through a systematic search in MEDLINE as well as on the authors' own experience and research.

RESULTS

Among patients who fulfill the established medical criteria, kidney transplantation results in better survival than lifelong dialysis treatment. The best prognosis is achieved if time on dialysis prior to transplantation is reduced and acute rejection episodes are avoided after transplantation.

INTERPRETATION

Kidney transplantation is a safe treatment for selected elderly patients with end-stage renal disease. Given a sufficient supply of organs, selected patients over 70 years of age with end-stage renal disease should be offered kidney transplantation following a standard medical assessment.

A review of utility-based allocation strategies to maximize graft years of deceased donor kidneys

With the continuing shortage of deceased donor kidneys coupled with a growing number of older potential recipients, there has been a greater acceptance of using older donor kidneys, including increased utility of expanded criteria donor (ECD) kidneys. In this review, we will look at the impact of using ECD kidneys on graft and patient survival, and to identify modifiable factors that may improve transplant outcomes in recipients receiving ECD kidneys. In addition, we will discuss whether the implementation of utility-based allocation strategies to maximize graft outcomes is an appropriate way forward to provide a better balance between utility and equity in the distribution of deceased donor kidneys.

The European experience

This mini-review on European experiences with tackling the problem of organ shortage for transplantation was based on a literature review of predominantly European publications dealing with the issue of organ donation from deceased donors. The authors tried to identify the most significant factors that have demonstrated to impact on donation rates from deceased donors and subsequent transplant successes. These factors include legislative measures (national laws and European Directives), optimization of the donation process, use of expanded criteria donors, innovative preservation and surgical techniques, organizational efforts, and improved allocation algorithms.

Benefit of kidney transplantation beyond 70 years of age

Background. Kidney transplantation generally improves long-term survival in patients with end-stage renal disease. However, in patients older than 70 years of age, only limited data are available that directly compare the potential survival benefit of transplantation versus dialysis.

Methods. All patients aged above 70 years who started dialysis between 1990 and 2005 and were waitlisted for kidney transplantation were included in the study. They were categorized according to time periods of inclusion (1990–99 vs 2000–05). Survival rates of altogether 286 dialysis patients were analyzed with a Kaplan–Meier model, as well as with a time-dependent Cox model. Comparisons were made between those who received a transplant and those who did not, and further between the two time periods.

Results. Median age at inclusion was 73.6 years (interquartile range 72.3–75.6). Two hundred and thirty-three patients (81%) received a kidney transplant during follow-up. Transplant recipients experienced an increased mortality in the first year after transplantation when compared to waitlisted patients. Patients starting dialysis between 1990 and 1999 had no significant long-term benefit of transplantation; HR for death 1.01 (0.58–1.75). In contrast, there was a substantial long-term benefit of transplantation among those starting dialysis after 2000; HR for death 0.40 (0.19–0.83), P = 0.014.

Conclusions. Survival after kidney transplantation in patients over 70 years has improved during the last decade and offers a survival advantage over dialysis treatment. Our experience supports the use of kidney transplantation in this age group if an increased early post-operative risk is accepted. This transplant policy may be challenged for priority reasons.