Expanded criteria donors: attempts to increase the renal transplant donor pool

Energy Metabolism and Metformin: Effects on Ischemia-Reperfusion Injury in Kidney Transplantation

Metformin (MTF) is the only biguanide included in the World Health Organization's list of essential medicines; representing a widespread drug in the management of diabetes mellitus. With its accessibility and affordability being one of its biggest assets, it has become the target of interest for many trying to find alternative treatments for varied pathologies. Over time, an increasing body of evidence has shown additional roles of MTF, with unexpected interactions of benefit in other diseases. Metformin (MTF) holds significant promise in mitigating ischemia-reperfusion injury (IRI), particularly in the realm of organ transplantation. As acceptance criteria for organ transplants expand, IRI during the preservation phase remain a major concern within the transplant community, prompting a keen interest in MTF's effects. Emerging evidence suggests that administering MTF during reperfusion may activate the reperfusion injury salvage kinase (RISK) pathway. This pathway is pivotal in alleviating IRI in transplant recipients, potentially leading to improved outcomes such as reduced rates of organ rejection. This review aims to contextualize MTF historically, explore its current uses, pharmacokinetics, and pharmacodynamics, and link these aspects to the pathophysiology of IRI to illuminate its potential future role in transplantation. A comprehensive survey of the current literature highlights MTF's potential to recondition and protect against IRI by attenuating free radical damage, activating AMP-activated protein kinase to preserve cellular energy and promote repair, as well as directly reducing inflammation and enhancing microcirculation.

Demographics of deceased donor renal transplants in Ireland: A 10 year review showing the worrying increase of suicide as a source for organ donation

INTRODUCTION

Kidney transplantation is the treatment of choice for patients with end stage renal disease. The primary aim of this study was to assess the demographics of deceased kidney donors over the last ten years and to assess for gender variations in deceased donor demographics over an extended period.

METHODS

A retrospective data analysis was carried out using data from the national renal transplant database. All deceased donors who donated a kidney between 1st January 2012 and 31st December 2021 were included. Data points extracted included gender, age, cause of death and month of death. Descriptive analyses were carried out using Excel v16.67.

RESULTS

A total of 1219 kidneys from 650 donors were donated over the ten-year period. The mean donor age was 44.01 years (range 1-74 years). The most common cause of death overall was subarachnoid haemorrhage (SAH), which was the cause of death in 27.8 % of donors (n = 180). Male donors accounted for 57.8 % of donors overall (n = 376). Variation in causes of death was observed between male and female donors, and between younger and older donors. 9 % of male deaths were from suicide compared with 5 % of female deaths. 6 % of male deaths were due to a traumatic head injury, with this accounting for 2 % of female deaths. Deaths due to assault made up 2 % of male donor deaths, but were not a cause of death for any female donors.

CONCLUSION

SAH and intracranial bleeds were the most common cause of death in both groups for deceased donor renal transplantation. Incidence of suicide as cause of death in deceased donors is rising in males.

Desenlaces a largo plazo en pacientes trasplantados renales con donantes de criterios expandidos: experiencia de 10 años

Introducción. El trasplante renal es el tratamiento de elección para la enfermedad renal crónica. Debido a la brecha con la disponibilidad de donantes, el uso de criterios expandidos es una opción que busca mejorar la tasa de donación mundial. El objetivo de este estudio fue comparar la sobrevida del injerto y del paciente trasplantado con donante de criterios expandidos versus el donante estándar. Métodos. Cohorte retrospectiva de 1002 pacientes con trasplante renal donde se determinó la sobrevida del injerto renal y del receptor a 10 años después del trasplante. La sobrevida del injerto renal y el receptor fueron estimadas por el método de Kaplan-Meier. Una regresión de Cox fue realizada ajustando el modelo multivariado. Resultados. El análisis incluyó 1002 receptores, con un 18,8 % (n=189) que correspondían al uso de donante de criterios expandidos. El grupo de trasplante renal con donante de criterios expandidos tuvo menor sobrevida del paciente (48,1 % versus 63,8 %) y del injerto (63,3 % versus 74,7 %) en comparación con el grupo de trasplante renal con donantes con criterios estándar a los 10 años después del trasplante. La asociación de trasplante renal con donante de criterios expandidos y muerte o pérdida del injerto renal no fueron significativas cuando se ajustaron las variables en el modelo multivariado. Conclusión. El trasplante renal con donante de criterios expandidos tiene menor sobrevida del receptor y del injerto frente al grupo de trasplante renal con donante estándar. No hubo diferencias estadísticamente significativas en cuanto al trasplante renal con donante de criterios expandidos frente a la pérdida del injerto renal o muerte.

Psychosocial Assessment of Living Organ Donors: Clinical and Ethical Considerations

This article outlines psychosocial and ethical issues to be considered when evaluating potential living organ donors. Six types of living donors are described: genetically related, emotionally related, “Good Samaritan” (both directed and nondirected), vendors, and organ exchangers. The primary domains to be assessed in the psychosocial evaluation are informed consent, motivation for donating and the decision-making process, adequacy of support (financial and social), behavioral and psychological health, and the donor-recipient relationship. Obstacles to the evaluation process include impression management, overt deception, minimization of behavioral risk factors, and cultural and language differences between the donor and the evaluator. Ethical concerns, such as the right to donate, donor autonomy, freedom from coercion, nonmaleficence and beneficence in donor selection, conflicts of interest, “reasonable” risks to donors, and recipient decision making are also explored. To fully evaluate living organ donation, studying psychosocial as well as medical outcomes is crucial.

YKL-40 Associates with Renal Recovery in Deceased Donor Kidney Transplantation

Deceased donor kidneys with AKI are often discarded for fear of poor transplant outcomes. Donor biomarkers that predict post-transplant renal recovery could improve organ selection and reduce discard. We tested whether higher levels of donor urinary YKL-40, a repair phase protein, associate with improved recipient outcomes in a prospective cohort study involving deceased kidney donors from five organ procurement organizations. We measured urinary YKL-40 concentration in 1301 donors (111 had AKI, defined as doubling of serum creatinine) and ascertained outcomes in the corresponding 2435 recipients, 756 of whom experienced delayed graft function (DGF). Donors with AKI had higher urinary YKL-40 concentration (P<0.001) and acute tubular necrosis on procurement biopsies (P=0.05). In fully adjusted analyses, elevated donor urinary YKL-40 concentration associated with reduced risk of DGF in both recipients of AKI donor kidneys (adjusted relative risk, 0.51 [95% confidence interval (95% CI), 0.32 to 0.80] for highest versus lowest YKL-40 tertile) and recipients of non-AKI donor kidneys (adjusted relative risk, 0.79 [95% CI, 0.65 to 0.97]). Furthermore, in the event of DGF, elevated donor urinary YKL-40 concentration associated with higher 6-month eGFR (6.75 [95% CI, 1.49 to 12.02] ml/min per 1.73 m²) and lower risk of graft failure (adjusted hazard ratio, 0.50 [95% CI, 0.27 to 0.94]). These findings suggest that YKL-40 is produced in response to tubular injury and is independently associated with recovery from AKI and DGF. If ultimately validated as a prognostic biomarker, urinary YKL-40 should be considered in determining the suitability of donor kidneys for transplant.

Increased plasma interleukin-6 in donors is associated with lower recipient hospital-free survival after cadaveric organ transplantation

OBJECTIVES

Brain death induces a massive inflammatory response. However, the influence of this inflammatory response on organ procurement, transplantation, and recipient outcome is unknown. We describe the inflammatory response characteristics in brain-dead organ donors and examine associations with organ transplantation and recipient survival. We test the hypothesis that increased inflammatory response is associated with fewer organs transplanted and decreased recipient survival.

DESIGN

Prospective, observational, cohort study.

SETTING

Two large intensive care units of tertiary care university hospitals in the United States.

PATIENTS

We recruited 30 consecutive brain-dead organ donors and 78 recipients between April 11, 2004, and November 23, 2004; recipients were followed through May 2005. Following declaration of brain death, we collected data on donor demographics, mechanism of brain death, number of organs procured and transplanted, and recipient characteristics. Plasma cytokines (tumor necrosis factor, interleukin-6, interleukin-10) were measured in donors at baseline following study enrollment, every hour for the first 4 hrs, and immediately before organ procurement for transplantation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We examined the relationships among clinical characteristics, demographics, and cytokine response in donors and their influence on organ procurement and transplantation using multivariable regression and recipient's 6-month hospital-free survival using a Cox proportional hazards regression. One hundred-eighteen organs were procured from 30 donors, and 91 (77%) were transplanted (mean of three organs transplanted per donor). All cytokines were increased following brain death. Older age in donors was significantly associated with lower number of organs transplanted (p < .001). Higher plasma interleukin-6 concentrations in donors before organ procurement was significantly associated with lower 6-month hospital-free survival in recipients (hazard ratio 1.77; 95% confidence interval, 1.17-2.69, p < .007).

CONCLUSIONS

Among brain-dead organ donors, older age donors contribute fewer organs for transplantation, and increased donor interleukin-6 level before organ procurement is associated with lower recipient six-month hospital-free survival.

[Laparoscopic nephrectomy in a living donor]

Kidney transplantation is the therapeutic option of choice for patients with end-stage renal disease. With the advent of safer harvesting techniques and immunosuppression, both donor and recipient outcomes have markedly improved in recent years. Kidney donation from Living donors remains the single most important factor responsible for improving patient and graft survival. The laparoscopic donor nephrectomy has revolutionized renal transplantation, allowing expansion of the donor pool by diminishing surgical morbidity while maintaining equivalent recipient outcome. This technique is now becoming the gold-standard harvesting procedure in transplant centres worldwide, despite its technical challenge and ongoing procedural maturation, especially early in the learning curve. Previous contraindications to laparoscopic donor nephrectomy are no longer absolute. In the following analysis, the procedural aspects of the laparoscopic donor nephrectomy are detailed including pre-operative assessment, operative technique and a review of the current literature delineating aspects of both donor and recipient morbidity and mortality compared with open harvesting techniques.

Transperitoneal laparoscopic live donor nephrectomy: Current status

Renal transplantation is the treatment of choice for a suitable patient with end stage renal disease. Unfortunately, the supply of donor organs is greatly exceeded by demand. In many countries the use of kidneys from living donors has been widely adopted as a partial solution. Traditionally donor nephrectomy has been performed via a open flank incision however with some morbidity like pain and a loin scar. Currently, the donor nephrectomy is increasingly being performed laparoscopically with the objective of reducing the morbidity. It is also hoped that this will lead to increasing acceptance of living donation. The first minimally invasive living donor nephrectomy was carried out in 1995 at the Johns Hopkins Medical Center and since then many centers have undertaken laparoscopic living donor nephrectomy. The laparoscopic approach substantially reduces the donor morbidity and wound related problems associated with open nephrectomy. The laparoscopic techniques thus have the potential to increase the number of living kidney donors. The present article attempts to review the safety and efficacy of transperitoneal laparoscopic donor nephrectomy.

Expanded Criteria Donors: Process and Outcomes

Expanded criteria donor (ECD) kidneys are transplantable deceased donor (DD) kidneys for which the average patient, graft survival, and renal function are inferior when compared to standard criteria DD kidneys. Although the term ECD kidneys has been used since the early 1990s to describe kidneys with various characteristics associated with poorer outcomes, the concept has been formally implemented in U.S. organ allocation. A DD kidney is considered to be an ECD organ if the estimated adjusted risk of graft failure is > or = 70% (RR > or = 1.70) compared to DD kidneys with standard characteristics of transplant suitability. The donor characteristics that define an ECD kidney include age > or = 60 years, or age 50-59 years plus two of the following: cerebrovascular accident as the cause of death, preexisting hypertension, or terminal serum creatinine greater than 1.5 mg/dl. In the aggregate, recipients of ECD kidneys have improved survival compared to end-stage renal disease (ESRD) patients on the kidney transplant waiting list. Patient survival is 5% lower at 1 year and 8-12% lower at 3-5 years for ECD kidney recipients. Adjusted graft survival in ECD kidneys is 8% lower at 1 year and 15-20% lower at 3-5 years after transplantation compared to standard criteria donor kidneys. However, patients less than 40 years of age, African Americans, Asians for whom the median waiting time is less than 1350 days receive no survival benefit from ECD kidney transplantation. Informed choice by the potential recipient is a prominent feature of the allocation policy regarding ECD kidneys. Since there are recipient characteristics associated with no survival benefit following ECD transplantation, nephrologists who refer patients for kidney transplantation should be familiar with the combination of donor and recipient factors that are likely to yield detrimental results.

Laparoscopic donor nephrectomy

Of the various options for patients with end stage renal disease, kidney transplantation is the treatment of choice for a suitable patient. The kidney for transplantation is retrieved from either a cadaver or a live donor. Living donor nephrectomy has been developed as a method to address the shortfall in cadaveric kidneys available for transplantation. Laparoscopic living donor nephrectomy (LLDN), by reducing postoperative pain, shortening convalescence, and improving the cosmetic outcome of the donor nephrectomy, has shown the potential to increase the number of living kidney donations further by removing some of the disincentives inherent to donation itself. The technique of LLDN has undergone evolution at different transplant centers and many modifications have been done to improve donor safety and recipient outcome. Virtually all donors eligible for an open surgical procedure may also undergo the laparoscopic operation. Various earlier contraindications to LDN, such as right donor kidney, multiple vessels, anomalous vasculature and obesity have been overcome with increasing experience. Laparoscopic live donor nephrectomy can be done transperitoneally or retroperitoneally on either side. The approach is most commonly transperitoneal, which allows adequate working space and easy dissection. A review of literature and our experience with regards to standard approach and the modifications is presented including a cost saving model for the developing countries. An assessment has been made, of the impact of LDN on the outcome of donor and the recipient.

The broad spectrum of quality in deceased donor kidneys

The quality of the deceased donor organ clearly is one of the most crucial factors in determining graft survival and function in recipients of a kidney transplant. There has been considerable effort made towards evaluating these organs culminating in an amendment to allocation policy with the introduction of the expanded criteria donor (ECD) policy. Our study, from first solitary adult deceased donor transplant recipients from 1996 to 2002 in the National Scientific Transplant Registry database, presents a donor kidney risk grade based on significant donor characteristics, donor-recipient matches and cold ischemia time, generated directly from their risk for graft loss. We investigated the impact of our donor risk grade in a naive cohort on short- and long-term graft survival, as well as in subgroups of the population. The projected half-lives for overall graft survival in recipients by donor risk grade were I (10.7 years), II (10.0 years), III (7.9 years), IV (5.7 years) and V (4.5 years). This study indicates that there is great variability in the quality of deceased donor kidneys and that the assessment of risk might be enhanced by this scoring system as compared to the simple two-tiered system of the current ECD classification.

Minimally Invasive Optimization of Organ Donor Resuscitation: Case Reports

Increased use of expanded donors requires optimal organ perfusion to prevent graft damage. In this regard, pulmonary artery catheters have been advocated to monitor hemodynamic status. Cost, catheter placement, and inconsistent management preclude broad use of pulmonary artery catheters. Esophageal Doppler monitoring also monitors hemodynamic status and can be instituted in minutes by an organ procurement coordinator. Concomitant assessment of acid-base balance using base excess and/or anion gap can help determine resuscitation efficacy. Esophageal Doppler monitoring is described to help salvage 2 hemodynamically deteriorating donors. Anion gap and corrected base excess identified poor resuscitation status in both donors and normalized after improvement in hemodynamic status. Compared to pulmonary artery catheters, esophageal Doppler monitoring may provide a more accessible means to assess and improve hemodynamic status. Base deficit and/or anion gap may determine resuscitation efficacy by exposing acid-base imbalance resulting from poor tissue perfusion. The full efficacy of this approach remains to be determined.

Extended criteria for organ acceptance. Strategies for achieving organ safety and for increasing organ pool

The terms extended donor or expanded donor mean changes in donor acceptability criteria. In almost all cases, the negative connotations of these terms cannot be justified. Factors considered to affect donor or organ acceptability have changed with time, after showing that they did not negatively affect graft or patient survival per se or when the adequate measures had been adopted. There is no age limit to be an organ donor. Kidney and liver transplantation from donors older than 65 years can have excellent graft and patient actuarial survival and graft function. Using these donors can be from an epidemiological point of view the most important factor to esablish the final number of cadaveric liver and kidney transplantations. Organs with broad structural parenchyma lesion with preserved functional reserve and organs with reversible functional impairment can be safely transplanted. Bacterial and fungal donor infection with the adequate antibiotic treatment of donor and/or recipient prevents infection in the latter. The organs, including the liver, from donors with infection by the hepatitis B and C viruses can be safely transplanted to recipients with infection by the same viruses, respectively. Poisoned donors and non-heart-beating donors, grafts from transplant recipients, reuse of grafts, domino transplant and splitting of one liver for two recipients can be an important and safe source of organs for transplantation.

Does cadaveric donor renal transplantation ever provide better outcomes than live-donor renal transplantation?

BACKGROUND

Live donor renal transplantation (LRT) now comprises more than 40% of all kidney transplants performed in the United States. Many patients on the cadaveric waiting list have a prospective live kidney donor. This study determines whether cadaveric donor renal transplantation (CRT) can demonstrate better outcomes than LRT.

METHODS

From the United States Renal Data System registry, 31,909 adult recipients of a first-time kidney transplant from 1995 to 1998 were analyzed. Recipients were followed until December 31, 2000.

RESULTS

CRT, more human leukocyte antigen (HLA) mismatches, increased donor age, cold ischemia time greater than 24 hr, African American recipient, and a history of diabetic nephropathy all increased the risk of graft failure, return to dialysis, and death. Nevertheless, in specific circumstances, CRT could provide better outcomes than LRT. For example, in recipients aged 18 to 59 years with a hypothetical live kidney donor aged 50 years and four HLA mismatches, the relative risk of graft loss with LRT is comparable or increased compared with CRT if the cadaveric kidney donor is much younger or with fewer HLA mismatches. On the other hand, for recipients aged 60 years or older, CRT never provides better outcomes than LRT. All analyses were adjusted for recipient race, gender, and history of diabetic nephropathy. There were no significant interactions among donor type, HLA mismatches, donor age, and cold ischemia time.

CONCLUSIONS

The elderly recipient with an imminent LRT should never be offered CRT. A combination of recipient and donor factors can make CRT preferable to LRT in younger patients.

Introduction of the certificate in transplant coordination in the United Kingdom

Training for transplant coordinators is not mandatory in the United Kingdom, although the United Kingdom Transplant Coordinators Association has provided informal courses since 1988. The authors of this article were responsible for the development of an accredited training program for transplant coordinators in the United Kingdom. Accredited by the University of Central England, the course modules have been run and managed by the Association since 1996. The course consists of 3 modules: Introduction to Transplant Coordination; Interpersonal and Professional Skills for Transplant Coordinators, and Introduction to Research Methods for Transplant Coordinators. Between 1996 and 1999, 64 transplant coordinators (60% of transplant coordinators currently in post) in the United Kingdom have undertaken at least 1 module. The Association feels that the accredited training program means one step further on the road to professional recognition of transplant coordinators in the United Kingdom.