Immunosuppression without calcineurin inhibition: optimization of renal function in expanded criteria donor renal transplantation

Kidney transplants from elderly donors: what we have learned 20 years after the Crystal City consensus criteria meeting

Based on the current projection of the general population and the combined increase in end-stage kidney disease with age, the number of elderly donors and recipients is increasing, raising crucial questions about how to minimize the discard rate of organs from elderly donors and improve graft and patient outcomes. In 2002, extended criteria donors were the focus of a meeting in Crystal City (VA, USA), with a goal of maximizing the use of organs from deceased donors. Since then, extended criteria donors have progressively contributed to a large number of transplanted grafts worldwide, posing specific issues for allocation systems, recipient management, and therapeutic approaches. This review analyzes what we have learned in the last 20 years about extended criteria donor utilization, the promising innovations in immunosuppressive management, and the molecular pathways involved in the aging process, which constitute potential targets for novel therapies.

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.

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.

Sirolimus versus tacrolimus in kidney transplant recipients receiving mycophenolate mofetil and steroids: focus on acute rejection, patient and graft survival

The study aims to conduct a meta-analysis of randomized controlled trials to compare the efficacy of tacrolimus (TAC)/mycophenolate mofetil (MMF)/corticosteroids (CSs) with sirolimus (SRL)/MMF/CSs in renal transplant recipients: Research 2 databases, PubMed, and Web of Science, selecting relevant articles. Data were selected for acute rejection and patient and graft survival. Statistical value relative risk (RR) and 95% confidence intervals (CIs) were recorded. Six randomized controlled trials involving 885 patients were included. There was a significant difference in acute rejection (P = 0.001, RR = 1.69, 95% CI, 1.23-2.34). Two groups, patient survival (P = 0.96, RR = 1.02, 95% CI, 0.54-1.91) and graft survival (P = 0.09, RR = 1.56, 95% CI, 0.93-2.60), had no statistical difference. Acute rejection by those taking SRL/MMF/CSs is worse than those taking TAC/MMF/CSs. Patient and graft survival in TAC/MMF/CSs is similar to that in SRL/MMF/CSs.

Kidney transplantation outcomes from expanded criteria donors, standard criteria donors or living donors older than 60 years

OBJECTIVES

To evaluate outcomes in kidney allograft recipients from donors with expanded criteria (ECD) versus standard criteria (SCD) or living donors (LD) >60 years.

METHODS

We studied all patients who received a kidney between 2005 and 2011, focusing in recipients of kidneys from deceased ECD, SCD and LD >60 years. ECD was any deceased donor >60 years or >50 years with two of the following: hypertension (HTN), stroke as the cause of death, or serum creatinine >1.5 mg/dL. We recorded characteristics of the transplant procedure, patient, graft survival and renal function 1 year after transplantation and at the end of follow-up.

RESULTS

Six-hundred and five patients were transplanted between 2005 and 2011 in our department. There were 142 (25.1%) transplantations from ECD, 192 (33.98%) from SCD and 96 (16.99%) from LDs older than 60 years. In a mean follow-up time of 36.4 months, graft survival rates were similar for all groups. Calculated GFR was found statistically different between the ECD and SCD groups, but still satisfactory at first year, and at end of follow-up time. Comparison of the patients, who received transplants from ECD, even older than 70 years, and those from LD >60 years revealed equivalent renal function in short and long term.

CONCLUSIONS

Utilization of marginal kidneys effectively doubled our deceased transplant volume in the period 2005-2011. Patients' and graft survival were shown similar at the end of follow-up for all groups. Renal outcomes were shown equivalent between the ECD and LD >60 years groups, and although significantly lower between the ECD and the SCD group, were still very satisfactory.

Monoclonal gammopathy of undetermined significance: a contraindication for living kidney donation?

During the last few years, the number of living donor kidney transplants has increased and this form of transplantation is currently the only option in some patients. We report two cases of living donor kidney transplantation in which the donor carried monoclonal gammopathy of undetermined significance. Neither of the two receptors has developed complications at 42 and 36 months after transplantation, respectively, and the donors have normal renal function and there is no evidence of progression to multiple myeloma.

Immunosuppression in high-risk transplantation

PURPOSE OF REVIEW

Increasingly, transplant clinicians are faced with providing candidates with increased risks for poorer outcome with donor grafts that also carry higher risks of failure. Understanding the role of immunosuppressive management in these combinations of higher risks remains important for optimizing results.

RECENT FINDINGS

Few immunosuppressive protocols have been rigorously tested in the high-risk renal transplant setting. The two main risk categories accounted for in the trials are those ones that confer increased risks to renal function, usually carried by the donor organs, and those protocols defined by increased risk for immunological failure, mostly determined by recipient characteristics. The studied protocols generally involve reduction or avoidance of nephrotoxic drugs in the first case and use of lymphocyte-depleting agents in the case of increased immunological risk. In both scenarios, acceptable short-term results have been achieved. However, long-term results for high-risk transplants defined either by donor or recipient factors have yet to be reported.

SUMMARY

The lack of long-term data for optimizing the right immunosuppressive regimen for a given donor/recipient risk profile remains an ongoing challenge for researchers and clinicians alike.