The combination of donor and recipient age is critical in determining host immunoresponsiveness and renal transplant outcome. Ann Surg. 2010;252:662-674. [PMID: 20881773 DOI: 10.1097/sla.0b013e3181f65c7d]

Relationship between early proteinuria and long term outcome of kidney transplanted patients from different decades of donor age

Background

Proteinuria after kidney transplantation portends a worse graft survival. However the magnitude of proteinuria related to patient and graft survival and its correlation with donor and recipient characteristics are poorly explored.

Methods

This study investigated the impact of post transplant proteinuria in the first year in 1127 kidney transplants analyzing the impact of different donor ages. Proteinuria cut off was set at 0.5 g/day.

Results

Transplants with proteinuria > 0.5 g/day correlated with poor graft and patient outcome in all donor age groups. In addition, 6-month-1-year proteinuria increase was significantly associated with graft outcome, especially with donors > 60 years old (p <  0.05; Odd Ratio 1.8). 1-year graft function (eGFR < or ≥ 44 ml/min) had similar impact to proteinuria (≥ 0.5 g/day) on graft failure (Hazard Ratio 2.77 vs Hazard Ratio 2.46). Low-grade proteinuria (0.2–0.5 g/day) demonstrated a trend for worse graft survival with increasing donor age. Also in kidney-paired analysis proteinuria ≥0.5 effect was more significant with donors > 50 years old (Odd Ratio 2.3).

Conclusions

Post-transplant proteinuria was increasingly harmful with older donor age. Proteinuria ≥0.5 g/day correlates with worse outcomes in all transplanted patients. Prognostic value of proteinuria and eGFR for graft and patient survival was comparable and these two variables remain significant risk factors even in a multivariate model that take into consideration the most important clinical variables (donor age, rejection, delayed graft function and cytomegalovirus viremia among others).

Everolimus in de novo kidney transplant recipients participating in the Eurotransplant senior program: Results of a prospective randomized multicenter study (SENATOR)

Early conversion to everolimus was assessed in kidney transplant recipients participating in the Eurotransplant Senior Program (ESP), a population in whom data are lacking. The SENATOR multicenter study enrolled 207 kidney transplant recipients undergoing steroid withdrawal at week 2 post-transplant (ClinicalTrials.gov [NCT00956293]). At week 7, patients were randomized (1:2 ratio) to continue the previous calcineurin inhibitor (CNI)-based regimen with mycophenolic acid (MPA) and cyclosporine or switch to a CNI-free regimen with MPA, everolimus (5–10 ng/mL) and basiliximab at weeks 7 and 12, then followed for 18 weeks to month 6 post-transplant. The primary endpoint was estimated GFR (eGFR). At week 7, 77/207 (37.2%) patients were randomized (53 everolimus, 24 control). At month 6, eGFR was comparable: 36.5±10.8ml/min with everolimus versus 42.0±13.0ml/min in the control group (p = 0.784). Discontinuation due to adverse events occurred in 27.8% of everolimus-treated patients and 0.0% of control patients (p = 0005). Efficacy profiles showed no difference. In conclusion, eGFR, safety and efficacy outcomes at month 6 post-transplant showed no difference between groups. The everolimus group experienced a higher rate of discontinuation due to adverse events. However, the high rate of non-randomization is highly relevant, indicating this to be a somewhat unstable patient population regardless of treatment.

Donor and recipient age matching in heart transplantation: analysis of the UNOS Registry

The association of donor and recipient age with survival following adult heart transplantation has not been well characterized. The purpose of this study was to examine the impact of the relationship between donor and recipient age on post-transplant survival. We retrospectively reviewed the 2005-2018 UNOS heart transplant database for all adult recipients undergoing first-time isolated heart transplantation. The impact of donor and recipient age on survival was analyzed with Cox proportional hazards modeling using restricted cubic splines. A total of 25 480 heart transplant donor and recipient pairs met inclusion criteria. Unadjusted and adjusted Cox proportional hazards modeling demonstrated a near-linear association between increasing donor age and decreased survival; in addition, older and younger recipient age was associated with decreased survival. After adjustment, there was no significant interaction between donor and recipient age. Older donors decreased survival similarly in both older and younger recipients. Increasing donor age and both younger and older recipient age are independently associated with worsened post-heart transplant survival. The relationship between donor and recipient age does not significantly affect survival following heart transplant.

Report from the American Society of Transplantation on frailty in solid organ transplantation

A consensus conference on frailty in kidney, liver, heart, and lung transplantation sponsored by the American Society of Transplantation (AST) and endorsed by the American Society of Nephrology (ASN), the American Society of Transplant Surgeons (ASTS), and the Canadian Society of Transplantation (CST) took place on February 11, 2018 in Phoenix, Arizona. Input from the transplant community through scheduled conference calls enabled wide discussion of current concepts in frailty, exploration of best practices for frailty risk assessment of transplant candidates and for management after transplant, and development of ideas for future research. A current understanding of frailty was compiled by each of the solid organ groups and is presented in this paper. Frailty is a common entity in patients with end-stage organ disease who are awaiting organ transplantation, and affects mortality on the waitlist and in the posttransplant period. The optimal methods by which frailty should be measured in each organ group are yet to be determined, but studies are underway. Interventions to reverse frailty vary among organ groups and appear promising. This conference achieved its intent to highlight the importance of frailty in organ transplantation and to plant the seeds for further discussion and research in this field.

Association of Cold Ischemia Time With Acute Renal Transplant Rejection

BACKGROUND

Kidney transplantation holds much promise as a treatment of choice for patients with end-stage kidney disease. The impact of cold ischemia time (CIT) on acute renal transplant rejection (ARTR) remains to be fully studied in a large cohort of renal transplant patients.

METHODS

From the Organ Procurement and Transplantation Network database, we analyzed 63 798 deceased donor renal transplants performed between 2000 and 2010. We assessed the association between CIT and ARTR. We also evaluated the association between recipient age and ARTR.

RESULTS

Six thousand eight hundred two (11%) patients were clinically diagnosed with ARTR. Longer CIT was associated with an increased risk of ARTR. After multivariable adjustment, compared with recipients with CIT < 12 hours, the relative risk of ARTR was 1.13 (95% confidence interval, 1.04-1.23) in recipients with CIT ≥ 24 hours. The association of CIT and ARTR was more pronounced in patients undergoing retransplantation: compared with recipients with CIT less than 12 hours, the relative risk of ARTR was 1.66 (95% confidence interval, 1.01-2.73) in recipients with CIT of 24 hours or longer. Additionally, older age was associated with a decreased risk of ARTR. Compared with recipients aged 18 to 29 years, the relative risk of ARTR was 0.50 (95% confidence interval, 0.45-0.57) in recipients 60 years or older. Longer CIT was also associated with increased risk of death-censored graft loss. Compared with recipients with CIT less than 12 hours, the hazard ratio of death-censored graft loss was 1.22 (95% confidence interval, 1.14-1.30) in recipients with CIT of 24 hours or longer.

CONCLUSIONS

Prolonged CIT is associated with an increased risk of ARTR and death-censored graft loss. Older age was associated with a lower risk of ARTR.

Implications of Frailty for Peritransplant Outcomes in Kidney Transplant Recipients

Purpose of Review

Research over the past few decades points to the importance of frailty, or the lack of physiologic reserve, in the natural history of chronic diseases and in modifying the impact of potential interventions. End-stage kidney disease (ESKD) and the intervention of kidney transplantation are no exception. We review the recent epidemiologic and cohort-based evidence on the association between frailty and kidney transplant outcomes and provide a framework of questions with which to approach future research endeavors and clinical practice.

Recent Findings

Frailty in kidney transplant candidates can be measured in numerous ways, including descriptive phenotype, description scores, functional testing, and surrogate measures. Regardless of the metric, the presence of frailty is strongly associated with inferior pre- and posttransplant outcomes compared to the absence of frailty. However, some frail patients with ESKD can benefit from transplant over chronic dialysis. Evidence-based approaches for identifying frail ESKD patients who can benefit from transplant over dialysis, with acceptable posttransplant outcomes, are lacking. Interventional trials to improve frailty and physical function before transplant (prehabilitation) and after transplant (rehabilitation) are also lacking.

Conclusion

Frailty is increasingly recognized as highly relevant to peritransplant outcomes, but more work is needed to: 1) tailor management to the unique needs of frail patients, both pre- and posttransplant; 2) define phenotypes of frail patients who are expected to benefit from transplant over dialysis; and 3) develop interventions to reverse frailty, both pre- and post-transplant.

Rapamycin Prolongs Graft Survival and Induces CD4+IFN-γ+IL-10+ Regulatory Type 1 Cells in Old Recipient Mice

BACKGROUND

Although the elderly represents a rapidly growing population among transplant recipients, age-specific aspects have not been considered sufficiently in clinical trials. Moreover, age-specific effects of immunosuppressive therapies remain poorly understood.

METHODS

Here, we assessed the impact of rapamycin on alloimmune responses in old recipients using a fully major histocompatibility complex-mismatched murine transplantation model.

RESULTS

Old untreated recipients displayed a prolonged skin graft survival compared to their young counterparts, an observation that confirmed data of our previous experiments. Rapamycin led to a significant prolongation of graft survival in both young and old recipients. However, graft survival was age-dependent and extended in old versus young recipients (19 days vs 12 days, P = 0.004). This age-specific effect was not linked to changes in frequencies or subset composition of either cluster of differentiation (CD)8 or CD4 T cells. Moreover, antiproliferative effects of rapamycin on CD8 and CD4 T cells as assessed by in vivo bromdesoxyuridine incorporation were comparable and age-independent. In contrast, the systemic production of IL-10 was markedly elevated in old recipients treated with rapamycin. In parallel to this shift in cytokine balance, IFN-γ/IL-10 double-positive regulatory type 1 cells emerged during T helper type 1 differentiation of old T helper cells in presence of rapamycin. Similarly, CD4IFN-γIL-10 cells expanded among Foxp3-negative cells after in vivo treatment of old recipients with rapamycin.

CONCLUSIONS

Our results highlight novel aspects of age-dependent immunosuppressive effects of rapamycin, with relevance for age-specific immunosuppressive regimens.

Increased T cell immunosenescence and accelerated maturation phenotypes in older kidney transplant recipients

Older kidney transplant recipients experience increased rates of infection and death, and less rejection, compared with younger patients. However, little is known about immune dysfunction in older compared with younger kidney transplant recipients and whether it is associated with infection. We evaluated T cell phenotypes including maturation, immune senescence, and exhaustion in a novel investigation into differences in older compared with younger patients receiving identical immune suppression regimens. We evaluated PBMC from 60 kidney transplant recipients (23 older and 37 matched younger patients) by multiparameter immune phenotyping. Older kidney transplant recipients demonstrated decreased frequency of naïve CD4+ and CD8+ T cells, and increased frequency of terminally differentiated, immune senescent, and NK T cells expressing KLRG1. There was a trend towards increased frequency of T cell immune senescence in patients experiencing infection in the first year after transplantation, which reached statistical significance in a multivariate analysis. This pilot study reveals immune dysfunction in older compared with younger transplant recipients, and suggests a likely mechanism for increased vulnerability to infection. The ability to assess T cell maturation and immune senescence in transplant recipients offers the potential for risk stratification and customization of immune suppression to prevent infection and rejection after transplantation.

Analyses of the short- and long-term graft survival after kidney transplantation in Europe between 1986 and 2015

The evolution of kidney allograft survival remains insufficiently studied in the context of the changing donor and recipient demographics. Since European data are lacking we performed a cohort study (1986-2015) that, based on the Collaborative Transplant Study, included 108 787 recipients of brain-death kidney donors in 135 hospitals across 21 European countries. We analyzed the hazard rate of kidney failure after transplantation. Between 1986 and 1999, improvement in graft survival was more pronounced in the short term than in the long term: one-, five- and ten-year hazard rates after transplantation declined 64% (95% confidence interval, 61%-66%), 53% (49%-57%) and 45% (39%-50%), respectively. Between 2000 and 2015, hazard rates at one, five and ten years post-transplant declined respectively 22% (12-30%), 47% (36-56%) and 64% (45-76%). Improvement in graft survival in the first five years post-transplant was significantly less since 2000, while improvement after five years was comparable to before. During the 2000-2015 period improvement of graft survival was greater in the long than in the short term. These changes were independent of changing donor and recipient characteristics, and reflect the evolution in global kidney transplant management over the past decades. Unfortunately, after accounting for the evolution of donor and recipient characteristics, we found that short-term improvement in graft survival decreased since 2000, while long-term improvement remained unchanged in Europe. Thus, deceleration of short-term graft survival improvement in more recent years illustrates an unmet need for innovation.

Usefulness of the KDPI in Spain: A comparison with donor age and definition of standard/expanded criteria donor

INTRODUCTION

Kidney donor shortage requires expanding donor selection criteria, as well as use of objective tools to minimize the percentage of discarded organs. Some donor pre-transplant variables such as age, standard/expanded criteria donor (SCD/ECD) definition and calculation of the Kidney Donor Profile Index (KDPI), have demonstrated correlations with patient and graft outcomes. We aimed to establish the accuracy of the three models to determine the prognostic value of kidney transplantation (KT) major outcomes.

MATERIAL AND METHODS

We performed a retrospective study in deceased donor KTs at our institution. Unadjusted Cox and Kaplan-Meier survival, and multivariate Cox analyses were fitted to analyze the impact of donor age, SCD/ECD and KDPI on outcomes.

RESULTS

389 KTs were included. Mean donor age was 53.6±15.2 years; 163 (41.9%) came from ECD; mean KDPI was 69.4±23.4%. Median follow-up was 51.9 months. The unadjusted Cox and Kaplan-Meier showed that the three prognostic variables of interest were related to increased risk of patient death, graft failure and death-censored graft failure. However, in the multivariate analysis only KDPI was related to a higher risk of graft failure (HR 1.03 [95% CI 1.01-1.05]; p=0.014).

CONCLUSIONS

SCD/ECD classification did not provide significant prognostic information about patient and graft outcomes. KDPI was linearly related to a higher risk of graft failure, providing a better assessment. More studies are needed before using KDPI as a tool to discard or accept kidneys for transplantation.

The Impact of Sex on Alloimmunity

Transplantation outcomes are known to be affected by multiple factors, including donor and recipient sex. Aside from the physiological characteristics of male and female donor allografts, accumulating evidence suggests that additional features underlie sex-specific immune responses that affect graft survival. We discuss here aspects of innate and adaptive alloimmunity that are specific to males and females in the context of underlying genetic and hormonal factors. These differences likely contribute to the observed disparities in graft survival. Understanding these features in more detail may lead to improved strategies for optimizing the results of organ transplantation.

Ischemia augments alloimmune injury through IL-6-driven CD4+ alloreactivity

Ischemia reperfusion injuries (IRI) are unavoidable in solid organ transplantation. IRI augments alloimmunity but the mechanisms involved are poorly understood. Herein, we examined the effect of IRI on antigen specific alloimmunity. We demonstrate that ischemia promotes alloimmune activation, leading to more severe histological features of rejection, and increased CD4+ and CD8+ T cell graft infiltration, with a predominantly CD8+ IFNγ+ infiltrate. This process is dependent on the presence of alloreactive CD4+ T cells, where depletion prevented infiltration of ischemic grafts by CD8+ IFNγ+ T cells. IL-6 is a known driver of ischemia-induced rejection. Herein, depletion of donor antigen-presenting cells reduced ischemia-induced CD8+ IFNγ+ allograft infiltration, and improved allograft outcomes. Following prolonged ischemia, accelerated rejection was observed despite treatment with CTLA4Ig, indicating that T cell costimulatory blockade failed to overcome the immune activating effect of IRI. However, despite severe ischemic injury, treatment with anti-IL-6 and CTLA4Ig blocked IRI-induced alloimmune injury and markedly improved allograft survival. We describe a novel pathway where IRI activates innate immunity, leading to upregulation of antigen specific alloimmunity, resulting in chronic allograft injury. Based on these findings, we describe a clinically relevant treatment strategy to overcome the deleterious effect of IRI, and provide superior long-term allograft outcomes.

Kidney transplant outcomes from older deceased donors: a paired kidney analysis by the European Renal Association-European Dialysis and Transplant Association Registry

As the median age of deceased kidney donors rises, updated knowledge of transplant outcomes from older deceased donors in differing donor-recipient age groups is required. Using ERA-EDTA Registry data we determined survival outcomes of kidney allografts donated from the same older deceased donor (55-70 years), and transplanted into one recipient younger and one recipient of similar age to the donor. The recipient pairs were divided into two groups: group 1; younger (median age: 52 years) and older (60 years) and group 2; younger (41 years) and older (60 years). A total of 1410 adults were transplanted during 2000-2007. Compared to the older recipients, the mean number of functioning graft years at 10 years was 6 months longer in the group 1 and group 2 younger recipients (P < 0.001). Ten-year graft survival was 54% and 40% for the group 1 younger and older recipients, and 60% and 49% for the group 2 younger and older recipients. Paired Cox regression analyses showed a lower risk of graft failure (group 1 younger; adjusted relative risk [RRa]:0.57, 95% CI:0.41-0.79, and group 2 younger; RRa:0.63, 95% CI:0.47-0.85) in younger recipients. Outcomes from older deceased donor allografts transplanted into differing donor-recipient age groups are better than previously reported. These allografts remain a valuable transplant resource, particularly for similar-aged recipients.

T-Cell Composition of the Lymph Node Is Associated with the Risk for Early Rejection after Renal Transplantation

Background

The T-cell composition within the lymph node (LN) of end-stage renal disease (ESRD) patients differs from the composition within the circulation. Activation of the alloreactive T-cell response within secondary lymphoid organs is important after organ transplantation. However, to date no data are present on LN T-cell subsets and the risk for acute rejection after kidney transplantation.

Methods

T cells from LNs of ESRD patients were analyzed for frequency of recent thymic emigrants, relative telomere length, expression of differentiation markers, and were related to the development of early acute rejection (EAR), occurring within 3 months after renal transplantation (RT). Furthermore, the alloreactive potential of mononuclear cells isolated from the LN and peripheral blood of 10 patients was analyzed. Measures of alloreactive potential included proliferation, cytokine production, frequencies of interferon-gamma-producing cells, and the presence of cytotoxic molecules.

Results

Patients with EAR were younger (p = 0.019), cytomegalovirus-seropositive (p = 0.037) and usually received dialysis prior to RT (p = 0.030). Next to this, patients with EAR showed a lower CD4:CD8 ratio (p = 0.027) within the LN. T cells from the LN were similar with regard to alloreactive capacity compared with those within the circulation. Univariate regression analysis showed that the CD4:CD8 ratio (OR: 0.67, p = 0.039), patient age (OR: 0.93, p = 0.024), and preemptive RT (OR: 0.11, p = 0.046) were associated with EAR. After a multivariate analysis, only the CD4:CD8 ratio (OR: 0.58, p = 0.019) and preemptive RT (OR:0.05, p = 0.012) were associated with EAR.

Conclusion

A lower CD4:CD8 ratio in the LN is associated with a higher risk for the development of rejection within 3 months after RT.

A Kidney Graft Survival Calculator that Accounts for Mismatches in Age, Sex, HLA, and Body Size

BACKGROUND AND OBJECTIVES

Outcomes for transplants from living unrelated donors are of particular interest in kidney paired donation (KPD) programs where exchanges can be arranged between incompatible donor-recipient pairs or chains created from nondirected/altruistic donors.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using Scientific Registry of Transplant Recipients data, we analyzed 232,705 recipients of kidney-alone transplants from 1998 to 2012. Graft failure rates were estimated using Cox models for recipients of kidney transplants from living unrelated, living related, and deceased donors. Models were adjusted for year of transplant and donor and recipient characteristics, with particular attention to mismatches in age, sex, human leukocyte antigens (HLA), body size, and weight.

RESULTS

The dependence of graft failure on increasing donor age was less pronounced for living-donor than for deceased-donor transplants. Male donor-to-male recipient transplants had lower graft failure, particularly better than female to male (5%-13% lower risk). HLA mismatch was important in all donor types. Obesity of both the recipient (8%-18% higher risk) and donor (5%-11% higher risk) was associated with higher graft loss, as were donor-recipient weight ratios of <75%, compared with transplants where both parties were of similar weight (9%-12% higher risk). These models are used to create a calculator of estimated graft survival for living donors.

CONCLUSIONS

This calculator provides useful information to donors, candidates, and physicians of estimated outcomes and potentially in allowing candidates to choose among several living donors. It may also help inform candidates with compatible donors on the advisability of joining a KPD program.

The Risk of Transplant Failure With HLA Mismatch in First Adult Kidney Allografts From Deceased Donors

BACKGROUND

Since the beginning of the technology, there has been active debate about the role of human leucocyte antigen (HLA) matching in kidney allograft survival. Recent studies have reported diminishing importance of HLA matching, which have, in turn, been challenged by reports that suggest the continuing importance of these loci. Given the controversies, we examined the effect of HLA compatibility on kidney allograft survival by studying all first adult kidney transplants in the United States from a deceased donor.

METHODS

Using the United Network for Organ Sharing data, we identified first deceased donor kidney transplants between October 1, 1987, and December 31, 2013. Recipients were classified by their number of HLA mismatches. Cox multivariate regression analyses adjusting for recipient and donor transplant characteristics were performed to determine the impact of HLA compatibility on kidney allograft survival.

RESULTS

Study cohort included 189 141 first adult kidney alone transplants, with a total of 994 558 years of kidney allograft follow-up time. Analyses adjusted for recipient and donor characteristics demonstrated a 13% higher risk (hazard ratio, 1.13; 95% confidence interval, 1.06-1.21) with 1 mismatch and a 64% higher risk (hazard ratio, 1.64, 95% confidence interval, 1.56-1.73) with 6 mismatches. Dividing the mismatch categories into 27 ordered permutations, and testing their 57 within mismatch category differences, demonstrated that all but 1 were equal, independent of locus.

CONCLUSIONS

A significant linear relationship of hazard ratios was associated with HLA mismatch and affects allograft survival even during the recent periods of increasing success in renal transplantation.

Histopathological evaluation of pretransplant donor biopsies in expanded criteria donors with high kidney donor profile index: a retrospective observational cohort study

There is no consensus on the allocation of renal transplants from expanded criteria donors (ECD). The Kidney Donor Profile Index (KDPI) is used without the need for pretransplant donor biopsies (PTDB). We explored whether PTDB based on Remuzzi Score (RS) allows identification of those marginal kidneys in the highest calculated KDPI risk group (>91%) that appropriate for single transplantation. A retrospective study was conducted of 485 consecutive kidneys procured from a single center and transplanted if the RS was ≤4. We compared 5-year kidney and patients survival between KDPI groups and between RS <4 or =4 in the highest KDPI group. The median KDPI (interquartile range) was 71 (66-76) for KDPI <80% (n = 77), 86 (81-90) for KDPI 81-90% (n = 82), and 97 (94-100) for KDPI >91% (n = 205). Patient survival at 5 years was 85.7%, 85.3%, and 76.09% (P = 0.058) and death-censored graft survival was 84.4%, 86.5%, 73.6% (P = 0.015), respectively for each KDPI group. In >91% calculated KDPI group, there were no differences in graft survival depending on the RS (<4 vs. =4) (P = 0.714). The implementation of PTDB based on RS used for allocation of organs with the highest KDPI range could support to the acceptance of suitable organs for single transplantation with good patient and graft survival rate.

A composite score associated with spontaneous operational tolerance in kidney transplant recipients

New challenges in renal transplantation include using biological information to devise a useful clinical test for discerning high- and low-risk patients for individual therapy and ascertaining the best combination and appropriate dosages of drugs. Based on a 20-gene signature from a microarray meta-analysis performed on 46 operationally tolerant patients and 266 renal transplant recipients with stable function, we applied the sparse Bolasso methodology to identify a minimal and robust combination of six genes and two demographic parameters associated with operational tolerance. This composite score of operational tolerance discriminated operationally tolerant patients with an area under the curve of 0.97 (95% confidence interval 0.94-1.00). The score was not influenced by immunosuppressive treatment, center of origin, donor type, or post-transplant lymphoproliferative disorder history of the patients. This composite score of operational tolerance was significantly associated with both de novo anti-HLA antibodies and tolerance loss. It was validated by quantitative polymerase chain reaction using independent samples and demonstrated specificity toward a model of tolerance induction. Thus, our score would allow clinicians to improve follow-up of patients, paving the way for individual therapy.

Strategies for an Expanded Use of Kidneys From Elderly Donors

The old-for-old allocation policy used for kidney transplantation (KT) has confirmed the survival benefit compared to remaining listed on dialysis. Shortage of standard donors has stimulated the development of strategies aimed to expand acceptance criteria, particularly of kidneys from elderly donors. We have systematically reviewed the literature on those different strategies. In addition to the review of outcomes of expanded criteria donor or advanced age kidneys, we assessed the value of the Kidney Donor Profile Index policy, preimplantation biopsy, dual KT, machine perfusion and special immunosuppressive protocols. Survival and functional outcomes achieved with expanded criteria donor, high Kidney Donor Profile Index or advanced age kidneys are poorer than those with standard ones. Outcomes using advanced age brain-dead or cardiac-dead donor kidneys are similar. Preimplantation biopsies and related scores have been useful to predict function, but their applicability to transplant or refuse a kidney graft has probably been overestimated. Machine perfusion techniques have decreased delayed graft function and could improve graft survival. Investing 2 kidneys in 1 recipient does not make sense when a single KT would be enough, particularly in elderly recipients. Tailored immunosuppression when transplanting an old kidney may be useful, but no formal trials are available.Old donors constitute an enormous source of useful kidneys, but their retrieval in many countries is infrequent. The assumption of limited but precious functional expectancy for an old kidney and substantial reduction of discard rates should be generalized to mitigate these limitations.

Long-Term Outcomes and Discard Rate of Kidneys by Decade of Extended Criteria Donor Age

BACKGROUND AND OBJECTIVES

Extended criteria donors represent nowadays a main resource for kidney transplantation, and recovery criteria are becoming increasingly inclusive. However, the limits of this approach are not clear as well as the effects of extreme donor ages on long-term kidney transplantation outcomes. To address these issues, we performed a retrospective study on extended criteria donor kidney transplantation.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In total, 647 consecutive extended criteria donor kidney transplantations performed over 11 years (2003-2013) were included. Donor, recipient, and procedural variables were classified according to donor age decades (group A, 50-59 years old [n=91]; group B, 60-69 years old [n=264]; group C, 70-79 years old [n=265]; and group D, ≥80 years old [n=27]). Organs were allocated in single- or dual-kidney transplantation after a multistep evaluation including clinical and histologic criteria. Long-term outcomes and main adverse events were analyzed among age groups and in either single- or dual-kidney transplantation. Kidney discard rate incidence and causes were evaluated.

RESULTS

Median follow-up was 4.9 years (25th; 75th percentiles: 2.7; 7.6 years); patient and graft survival were comparable among age groups (5-year patient survival: group A, 87.8%; group B, 88.1%; group C, 88.0%; and group D, 90.1%; P=0.77; graft survival: group A, 74.0%; group B, 74.2%; group C, 75.2%; and group D, 65.9%; P=0.62) and between dual-kidney transplantation and single-kidney transplantation except for group D, with a better survival for dual-kidney transplantation (P=0.04). No difference was found analyzing complications incidence or graft function over time. Kidney discard rate was similar in groups A, B, and C (15.4%, 17.7%, and 20.1%, respectively) and increased in group D (48.2%; odds ratio, 5.1 with A as the reference group; 95% confidence interval, 2.96 to 8.79).

CONCLUSIONS

Discard rate and long-term outcomes are similar among extended criteria donor kidney transplantation from donors ages 50-79 years old. Conversely, discard rate was strikingly higher among kidneys from octogenarian donors, but appropriate selection provides comparable long-term outcomes, with better graft survival for dual-kidney transplantation.

Older candidates for kidney transplantation: Who to refer and what to expect?

The number of older end-stage renal disease patients being referred for kidney transplantation continues to increase. This rise is occurring alongside the continually increasing prevalence of older end-stage renal disease patients. Although older kidney transplant recipients have decreased patient and graft survival compared to younger patients, transplantation in this patient population is pursued due to the survival advantage that it confers over remaining on the deceased donor waiting list. The upper limit of age and the extent of comorbidity and frailty at which transplantation ceases to be advantageous is not known. Transplant physicians are therefore faced with the challenge of determining who among older patients are appropriate candidates for kidney transplantation. This is usually achieved by means of an organ systems-based medical evaluation with particular focus given to cardiovascular health. More recently, global measures of health such as functional status and frailty are increasingly being recognized as potential tools in risk stratifying kidney transplant candidates. For those candidates who are deemed eligible, living donor transplantation should be pursued. This may mean accepting a kidney from an older living donor. In the absence of any living donor, the choice to accept lesser quality kidneys should be made while taking into account the organ shortage and expected waiting times on the deceased donor list. Appropriate counseling of patients should be a cornerstone in the evaluation process and includes a discussion regarding expected outcomes, expected waiting times in the setting of the new Kidney Allocation System, benefits of living donor transplantation and the acceptance of lesser quality kidneys.

A high intrapatient variability in tacrolimus exposure is associated with poor long-term outcome of kidney transplantation

Tacrolimus is a critical dose drug with a considerable intrapatient variability (IPV) in its pharmacokinetics. We investigated whether a high IPV in tacrolimus exposure is associated with adverse long-term renal transplantation outcomes. Tacrolimus IPV was calculated from predose concentrations measured between 6 and 12 months post-transplantation of 808 renal transplant recipients (RTRs) transplanted between 2000 and 2010. One hundred and eighty-eight (23.3%) patients reached the composite end point consisting of graft loss, late biopsy-proven rejection, transplant glomerulopathy, or doubling of serum creatinine concentration between month 12 and the last follow-up. The cumulative incidence of the composite end point was significantly higher in patients with high IPV than in patients with low IPV (hazard ratio: 1.41, 95% CI: 1.06-1.89; P = 0.019). After the adjustment for several factors, the higher incidence of the composite end point for RTRs with a high IPV remained statistically significant (hazard ratio: 1.42, 95% CI: 1.06-1.90; P = 0.019). Younger recipient age at transplantation, previous transplantation, worse graft function (at month 6 post-transplantation), and low mean tacrolimus concentration at 1 year post-transplantation were additional predictors for worse long-term transplant outcome. A high tacrolimus IPV is an independent risk factor for adverse kidney transplant outcomes that can be used as an easy monitoring tool to help identify high-risk RTRs.

LCPT once-daily extended-release tacrolimus tablets versus twice-daily capsules: a pooled analysis of two phase 3 trials in important de novo and stable kidney transplant recipient subgroups

African-American and elderly kidney transplant recipients (KTR) have increased risk for poor clinical outcomes post-transplant. Management of immunosuppression may be challenging in these patients and contribute to worse outcomes. A novel once-daily formulation of tacrolimus (LCPT) has demonstrated noninferiority, similar safety, improved bioavailability, a consistent concentration time profile, and less peak and peak-trough fluctuations vs. tacrolimus twice-daily (Tac BID). This pooled analysis of two phase 3 randomized, controlled trials, including 861 (LCPT N = 428; Tac BID N = 433; 38% of patients were stable KTR, and 62% were de novo KTR) patients, examined the efficacy of LCPT in KTR subgroups (blacks, females, and age ≥65). Overall, treatment failure [death, graft failure, centrally read biopsy-proven acute rejection (BPAR), or lost to follow-up] at 12 months was as follows: LCPT: 11.9%, BID Tac: 13.4% [-1.48% (-5.95%, 2.99%)]. BPAR rates were as follows: LCPT: 8.2%, Tac BID: 9.5% [-1.29% (-5.14%, 2.55%)]. Numerically, fewer treatment failure events with LCPT were found in the majority of subgroups, with significantly less treatment failure associated with LCPT among black KTR [-13.82% (-27.22%, -0.31%)] and KTR ≥65 [-13.46% (-25.27%, -0.78%)]. This pooled analysis suggests numerically lower efficacy failure rates associated with LCPT among high-risk subgroups, in particular black KTR and KTR ≥65 years old.

Renal transplantation with expanded criteria donors: Which is the optimal immunosuppression?

The growing gap between demand and supply for kidney transplants has led to renewed interest in the use of expanded criteria donor (ECD) kidneys in an effort to increase the donor pool. Although most studies of ECD kidney transplantation confirm lower allograft survival rates and, generally, worse outcomes than standard criteria donor kidneys, recipients of ECD kidneys generally have improved survival compared with wait-listed dialysis patients, thus encouraging the pursuit of this type of kidney transplantation. The relative benefits of transplantation using kidneys from ECDs are dependent on patient characteristics and the waiting time on dialysis. Because of the increased risk of poor graft function, calcineurin inhibitor (CNI)-induced nephrotoxicity, increased incidence of infections, cardiovascular risk, and malignancies, elderly recipients of an ECD kidney transplant are a special population that requires a tailored immunosuppressive regimen. Recipients of ECD kidneys often are excluded from transplant trials and, therefore, the optimal induction and maintenance immunosuppressive regimen for them is not known. Approaches are largely center specific and based upon expert opinion. Some data suggest that antithymocyte globulin might be the preferred induction agent for elderly recipients of ECD kidneys. Maintenance regimens that spare CNIs have been advocated, especially for older recipients of ECD kidneys. CNI-free regimens are not universally accepted due to occasionally high rejection rates. However, reduced CNI exposure and CNI-free regimens based on mammalian target of rapamycin inhibitors have shown acceptable outcomes in appropriately selected ECD transplant recipients.

Dual kidney transplants from adult marginal donors successfully expand the limited deceased donor organ pool

BACKGROUND

The need to expand the organ donor pool remains a formidable challenge in kidney transplantation (KT). The use of expanded criteria donors (ECDs) represents one approach, but kidney discard rates are high because of concerns regarding overall quality. Dual KT (DKT) may reduce organ discard and optimize the use of kidneys from marginal donors.

STUDY DESIGN

We conducted a single-center retrospective review of outcomes in adult recipients of DKTs from adult marginal deceased donors (DD) defined by limited renal functional capacity. If the calculated creatinine clearance in an adult DD was <65 mL/min, then the kidneys were transplanted as a DKT.

RESULTS

Over 11.5 yr, 72 DKTS were performed including 45 from ECDs, 17 from donation after cardiac death (DCD) donors, and 10 from standard criteria donors (SCD). Mean adult DD and recipient ages were both 60 yr, including 29 DDs and 26 recipients ≥65 yr of age. Mean pre-DKT waiting and dialysis vintage times were 12 months and 25 months, respectively. Actual patient and graft survival rates were 84.7% and 70.8%, respectively, with a mean follow-up of 58 months. One yr and death-censored graft survival rates were 90% and 80%, respectively. Outcomes did not differ by DD category, recipient age, or presence of delayed graft function (DGF). Eleven patients died at a mean of 32 months post-DKT (eight with functioning grafts) and 13 other patients experienced graft losses at a mean of 33 months. The incidence of DGF was 25%; there were two cases (2.8%) of primary non-function. Mean length of initial hospital stay was 7.2 d. Mean serum creatinine and glomerular filtration rate levels at 12 and 24 months were 1.5 and 53 and 1.5 mg/dL and 51 mL/min/1.73 m(2) , respectively. DKT graft survival and function were superior to concurrent single ECD and similar to concurrent SCD KTs. Two patients underwent successful kidney retransplantation, so the dialysis-free rate in surviving patients was 87%. The proportion of total renal function transplanted from adult DD to DKT recipients was 77% compared to 56% for patients receiving single KTs.

CONCLUSIONS

Dual kidney transplantation using kidneys from adult marginal DDs that otherwise might be discarded offer a viable option to counteract the growing shortage of acceptable single kidneys. Excellent medium-term outcomes can be achieved and waiting times can be reduced in a predominantly older recipient population.

A Rationale for Age-Adapted Immunosuppression in Organ Transplantation

Demographic changes are associated with a steady increase of older patients with end-stage organ failure in need for transplantation. As a result, the majority of transplant recipients are currently older than 50 years, and organs from elderly donors are more frequently used. Nevertheless, the benefit of transplantation in older patients is well recognized, whereas the most frequent causes of death among older recipients are potentially linked to side effects of their immunosuppressants.Immunosenescence is a physiological part of aging linked to higher rates of diabetes, bacterial infections, and malignancies representing the major causes of death in older patients. These age-related changes impact older transplant candidates and may have significant implications for an age-adapted immunosuppression. For instance, immunosenescence is linked to lower rates of acute rejections in older recipients, whereas the engraftment of older organs has been associated with higher rejection rates. Moreover, new-onset diabetes mellitus after transplantation is more frequent in the elderly, potentially related to corticosteroids, calcineurin inhibitors, and mechanistic target of rapamycin inhibitors.This review presents current knowledge for an age-adapted immunosuppression based on both, experimental and clinical studies in and beyond transplantation. Recommendations of maintenance and induction therapy may help to improve graft function and to design future clinical trials in the elderly.

Novel Once-Daily Extended-Release Tacrolimus Versus Twice-Daily Tacrolimus in De Novo Kidney Transplant Recipients: Two-Year Results of Phase 3, Double-Blind, Randomized Trial

BACKGROUND

1-year data from this trial showed the noninferiority of a novel once-daily extended-release tacrolimus (LCPT; Envarsus XR) to immediate-release tacrolimus (IR-Tac) twice daily after kidney transplantation.

STUDY DESIGN

Final 24-month analysis of a 2-armed, parallel-group, randomized, double-blind, double-dummy, multicenter, phase 3 trial.

SETTING & PARTICIPANTS

543 de novo kidney recipients randomly assigned to LCPT (n=268) or IR-Tac (n=275); 507 (93.4%) completed the 24-month study.

INTERVENTION

LCPT tablets once daily at 0.17 mg/kg/d or IR-Tac twice daily at 0.1 mg/kg/d; subsequent doses were adjusted to maintain target trough ranges (first 30 days, 6-11 ng/mL; thereafter, 4-11 ng/mL). The intervention was 24 months; the study was double blinded for the entirety.

OUTCOMES & MEASUREMENTS

Treatment failure (death, transplant failure, biopsy-proven acute rejection, or loss to follow up) within 24 months. Safety end points included adverse events, serious adverse events, new-onset diabetes, kidney function, opportunistic infections, and malignancies. Pharmacokinetic measures included total daily dose (TDD) of study drugs and tacrolimus trough levels.

RESULTS

24-month treatment failure was LCPT, 23.1%; IR-Tac, 27.3% (treatment difference, -4.14% [95% CI, -11.38% to +3.17%], well below the +10% noninferiority criterion defined for the primary 12-month end point). Subgroup analyses showed fewer treatment failures for LCPT versus IR-Tac among black, older, and female recipients. Safety was similar between groups. From month 1, TDD was lower for LCPT; the difference increased over time. At month 24, mean TDD for LCPT was 24% lower than for the IR-Tac group (P<0.001), but troughs were similar (means at 24 months: LCPT, 5.47 ± 0.17 ng/mL; IR-Tac, 5.8 ± 0.30 ng/mL; P=0.4).

LIMITATIONS

Trial participant eligibility criteria may limit the generalizability of results to the global population of de novo kidney transplant recipients.

CONCLUSIONS

Results suggest that once-daily LCPT in de novo kidney transplantation has comparable efficacy and safety profile to that of IR-Tac. Lower TDD reflects LCPT's improved bioavailability and absorption.

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.

Risk Stratification for Rejection and Infection after Kidney Transplantation

BACKGROUND AND OBJECTIVES

Definition of individual risk profile is the first step to implement strategies to keep the delicate balance between under- and overimmunosuppression after kidney transplantation.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We used data from the Efficacy Limiting Toxicity Elimination Symphony Study (1190 patients between 2002 and 2004) to model risk of rejection and infection in the first year after kidney transplantation. External validation was performed in a study population from the Fixed-Dose Concentration-Controlled Trial (630 patients between 2003 and 2006).

RESULTS

Despite different temporal dynamics, rejections and severe infections had similar overall incidences in the first year after transplantation (23.4% and 25.5%, respectively), and infections were the principal cause of death (43.2% of all deaths). Recipient older age, deceased donor, higher number of HLA mismatches, and high risk for cytomegalovirus disease were associated with infection; deceased donor, higher number of HLA mismatches, and immunosuppressive therapy including cyclosporin A (compared with tacrolimus), with rejection. These factors were integrated into a two-dimensional risk stratification model, which defined four risk groups: low risk for infection and rejection (30.8%), isolated risk for rejection (36.1%), isolated risk for infection (7.0%), and high risk for infection and rejection (26.1%). In internal validation, this model significantly discriminated the subgroups in terms of composite end point (low risk for infection/rejection, 24.4%; isolated risk for rejection and isolated risk for infection, 31.3%; high risk for infection/rejection, 54.4%; P<0.001), rejection episodes (isolated risk for infection and low risk for infection/rejection, 13.0%; isolated risk for rejection and high risk for infection/rejection, 24.2%; P=0.001), and infection episodes (low risk for infection/rejection and isolated risk for rejection, 12.0%; isolated risk for infection and high risk for infection/rejection, 37.6%; P<0.001). External validation confirmed the applicability of the model to an independent cohort.

CONCLUSIONS

We propose a two-dimensional risk stratification model able to disentangle the individual risk for rejection and infection in the first year after kidney transplantation. This concept can be applied to implement a personalized immunosuppressive and antimicrobial treatment approach.

Understanding alterations in drug handling with aging: a focus on the pharmacokinetics of maintenance immunosuppressants in the elderly

PURPOSE OF REVIEW

This review presents current knowledge of the impact of age on the pharmacokinetics of maintenance immunosuppressants.

RECENT FINDINGS

Over the past decade, there has been a steady increase in older patients on organ transplant waiting lists. As a result, the average age of transplant recipients has significantly increased. The survival and quality-of-life benefits of transplantation in the elderly population have been demonstrated. Advancing age is associated with changes in immune responses, as well as changes in drug handling. Immunosenescence is a physiological part of aging and is linked to reduced rejection rates, but also higher rates of diabetes, infections and malignancies. Physiologic changes associated with age can have a significant impact on the pharmacokinetics of the maintenance immunosuppressive agents. Taken together, these age-related changes impact older transplant candidates and may have significant implications for managing immunosuppression in the elderly.

SUMMARY

Despite the lack of formal efficacy, safety and pharmacokinetic studies of individual immunosuppressants in the elderly transplant population, there are enough data available for practitioners to be able to adequately manage their older patients. A proficient understanding of the factors that impact the pharmacokinetics of the immunosuppressants in the elderly is essential to managing these patients successfully.

Immunosenescence in renal transplantation: a changing balance of innate and adaptive immunity

PURPOSE OF REVIEW

With global demographic changes and an overall improved healthcare, more older end-stage renal disease (ESRD) patients receive kidney transplants. At the same time, organs from older donors are utilized more frequently. Those developments have and will continue to impact allocation, immunosuppression and efforts improving organ quality.

RECENT FINDINGS

Findings mainly outside the field of transplantation have provided insights into mechanisms that drive immunosenescence and immunogenicity, thus providing a rationale for an age-adapted immunosuppression and relevant clinical trials in the elderly. With fewer rejections in the elderly, alloimmune responses appear to be characterized by a decline in effectiveness and an augmented unspecific immune response.

SUMMARY

Immunosenescence displays broad and ambivalent effects in elderly transplant recipients. Those changes appear to compensate a decline in allospecific effectiveness by a shift towards an augmented unspecific immune response. Immunosuppression needs to target those age-specific changes to optimize outcomes in elderly transplant recipients.

What immunosuppression should be used for old-to-old recipients?

Elderly patients receiving a kidney from old donors (old-to-old) are a growing population of transplant recipients. This population cumulates risks of complications due to the co-morbidities and the immunodeficiency state and the frailty of the recipients together with the kidney senescence of the donors. In this context, the choice of immunosuppression is complicated and must take into account some contradictory principles explaining why no consensus exists today.

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.

Simultaneous pancreas and kidney transplantation: current trends and future directions

Purpose of review

Important trends are being observed in pancreas transplantation in the USA. We will describe recent trends in simultaneous pancreas kidney (SPK) transplantation related to immunosuppression, treatment of rejection, and transplantation for patients of advanced age and C-peptide positive diabetes.

Recent findings

Rates of pancreas transplantation have declined, despite improved pancreatic graft outcomes. Regarding immunosuppression, trends in SPK transplantation include T-cell depletion induction therapy, waning mammalian target of rapamycin inhibitor use and steroid use in greater than 50% of pancreas transplant recipients with few patients undergoing late steroid weaning. Rejection of the pancreas may be discordant with the kidney after SPK and there is a greater appreciation of antibody-mediated rejection of the pancreas allograft. De-novo donor-specific antibody without graft dysfunction remains an active area of study, and the treatment for this condition is unclear. SPKs are being performed with greater frequency in type 2 diabetes mellitus patients and in patients of advanced age, with exemplary results.

Summary

The current state of the art in SPK transplantation is yielding superb and improving results.