The cadaveric kidney and the organ shortage--a perspective review

Perigraft fluid collections after kidney transplantation: Does the type of donor (uncontrolled donation after circulatory death vs. donation after brain death) have a role?

Introduction

Perigraft fluid collection (PFC) is a common complication after kidney transplant. Its etiology is not clear and not all the causes have been identified. The influence of the type of donor has never been evaluated. Our aim was to compare the incidence, severity and management of PFC in recipients of grafts from uncontrolled donors after circulatory death (DCD) with normothermic extracorporeal membrane oxygenation (NECMO) versus recipients of grafts from donors after brain death (DBD).

Material and methods

We conducted a retrospective cohort study of 300 kidney transplants performed in our center between 2007 and 2012. Patients were divided in two groups: 150 recipients of Maastricht II DCD graft and 150 recipients of the DBD graft. Incidence, severity according to Clavien scale and management were analyzed in both groups, and comparison was carried out using Chi-square.

Results

Of the 300 kidney recipients analyzed, 93 (31.4%) suffered PFC, showing no difference between DBD (32.0%) and DCD (30.8%) groups (p = 0.9). Complicated PFC rate (defined as a PFC generating vascular compression, fever or urinary tract obstruction) was 22.9% in the DBD group versus 22.2% in the DCD group (p = 1); most complicated PFC were due to urinary tract obstruction (81%), with no difference between the groups (p = 1). Concerning Clavien scale, 78.5% of the PFC in our series were Clavien I, 19.4% Clavien IIIa and 2.2% Clavien IIIb, with no difference between both groups (p = 1).

Conclusions

PFC is a frequent complication that appears in a third of our patients, showing no difference in the incidence or severity between DBD and uncontrolled DCD graft recipients.

Kidney transplantation after oxygenated machine perfusion preservation with Custodiol-N solution

Custodiol-N, a new preservation solution, has been shown particularly suitable for hypothermic machine perfusion preservation (HMP) in isolated porcine kidneys. These preliminary results should be confirmed in an actual transplant model in vivo. Kidney function after 21 h of HMP was studied in an autotransplant model using Landrace pigs (25-30 kg; n = 6 per group). Perfusion was performed with oxygenated perfusate, using either Custodiol-N solution including 50 g/l dextran 40 (CND) or kidney perfusion solution 1 (KPS-1) as gold standard. Viability of the grafts was followed for 1 week after bilateral nephrectomy in the recipient pigs. HMP with CND resulted in less acute tubular injury, evaluated by levels of fatty acid-binding protein and better clearance function during the first 24 h after Tx than with KPS-1 (P < 0.05, resp.). Serum creatinine tended to be lower in the CND group during the whole observation period. Histological tissue scores one week after Tx were similar in both groups. Expression of endothelin-1 as well as of Toll-like receptor 4 15 min after reperfusion was lower in the CND group (P < 0.05), suggesting less endothelial stress response. The data provide first in vivo evidence for the suitability of Custodiol-N as an effective perfusate for renal machine perfusion.

Hypothermic reconditioning by gaseous oxygen persufflation after cold storage of porcine kidneys

BACKGROUND

Delayed graft function still represents a major complication in clinical kidney transplantation. Here we tested the possibility to improve functional outcome of cold stored kidneys a posteriori by hypothermic reconditioning using retrograde oxygen persufflation (ROP) immediately prior to reperfusion.

METHODS

Kidneys from female German Landrace pigs were flushed with Histidine-Tryptophan-Ketoglutarate (HTK) solution and cold-stored for 18 h (control). Some grafts were subsequently subjected to 90 min of retrograde oxygen persufflation (ROP) via the renal vein during cold preservation. Early graft function of all kidneys was assessed thereafter by warm reperfusion in vitro (n=6, resp.).

RESULTS

Renal function upon reperfusion was significantly enhanced by ROP with an approximately twofold increase in renal clearances of creatinine and urea. ROP also led to higher renal vascular flow rates, enhanced urine output and mitigated histological alterations.

CONCLUSION

It is concluded that initial graft function can be improved by 90 min of hypothermic gaseous oxygenation after arrival of the preserved organ in the transplantation clinic.

Dopamine as additive to cold preservation solution improves postischemic integrity of the liver

Dopamine pretreatment has been used to confer protection against cellular injury following hypothermia or anoxia, especially in vascular endothelial cells. Ischemia/reperfusion-associated tissue alterations still represent a major drawback in liver transplantation. The present study was aimed to investigate the effect of dopamine as an ex vivo adjunct, added to the cold storage solution, on cold preservation of the liver. Rat livers were excised 30 min after cardiac arrest, flushed with preservation solution and cold stored for 18 h. Dopamine (10, 50 or 100 microM) was added to the preservation solution in other livers. Organ viability was evaluated by 120 min of warm reperfusion in vitro (n = 6, resp.). Dopamine induced a dose related up to fourfold (at 50 mum) reduction in parenchymal (ALT, LDH) and mitochondrial (GLDH) enzyme release and significantly reduced histologic signs of tissue injury. Bile production and tissue ATP was doubled by dopamine. On the molecular level, dopamine enhanced postischemic phosphorylation of protein kinase A and p42/44 MAP kinase. Inhibition of cAMP-PKA pathway by simultaneous application of RP-cAMPs had no effect on P42/44 phosphorylation, or functional recovery of dopamine-treated grafts. Dopamine supplementation of the flush-out solution appears as a simple way for ex vivo augmentation of liver viability during preservation, not mediated via the catecholamine-cAMP signal cascade.

Hypothermic reconditioning after cold storage improves postischemic graft function in isolated porcine kidneys

Delayed graft function still represents a major complication in clinical kidney transplantation. Here we tested the possibility to improve functional outcome of cold stored kidneys a posteriori by short-term hypothermic machine perfusion immediately prior to reperfusion. A total of 18 kidneys from female German Landrace pigs was flushed with Histidine-Tryptophan-Ketoglutarate solution and cold-stored for 18 h (control). Some grafts were subsequently subjected to 90 min of hypothermic reconditioning by hypothermic machine perfusion with (HR+O(2)) or without (HR-O(2)) oxygenation of the perfusate. Early graft function of all kidneys was assessed thereafter by warm reperfusion in vitro (n = 6, respectively). Renal function upon reperfusion was significantly enhanced by HR+O(2) with more than threefold increase in renal clearances of creatinine and urea. HR+O(2) also led to significantly higher urinary flow rates and abrogated the activation of caspase 3. By contrast, HR-O(2) was far less effective and only resulted in minor differences compared to control. It is derived from the present data that initial graft function can be significantly improved by 2 h of oxygenated machine perfusion after arrival of the preserved organ in the transplantation clinic.

The expanded criteria donor policy: an evaluation of program objectives and indirect ramifications

The expanded criteria donor (ECD) policy was formalized in 2002, which defined higher-risk deceased donor kidneys recovered for transplantation. There has not been a comprehensive examination of the impact of policy on the allocation of ECD kidneys, waiting times for transplant, center listing patterns or human leukocyte antigen (HLA) matching. We examined transplant candidates from 1998 to 2004 utilizing a national database. We constructed models to assess alterations in recipient characteristics of ECD kidneys and trends in waiting time and cold ischemia time (CIT) associated with policy. We also evaluated the impact of the proportion of center candidate listings for ECD kidneys on waiting times. Elderly recipients were more likely to receive ECDs following policy (odds ratio = 1.36, p < 0.01). There was no association of decreased CIT or pretransplant dialysis time while increasing HLA mismatching with policy inception. Over one quarter of centers listed < 20% of candidates for ECDs, while an additional quarter of centers listed > 90%. Only centers with selective listing for ECDs offered reduced waiting times to ECD recipients. The ECD policy demonstrates potential to achieve certain ascribed goals; however, the full impact of the program, reaching all transplant candidates, may only be achieved once ECD listing patterns are recommended and adopted accordingly.

Beyond Operational Tolerance: Effect of Ischemic Injury on Development of Chronic Damage in Renal Grafts

BACKGROUND

The induction of operational tolerance is the holy grail of clinical transplantation. However, in animal models with operational tolerance, long- term grafts still develop chronic damage. The elucidation of the impact of allogenic versus nonallogeneic factors in such a model is important. This study examined the effect of a clinically relevant combination of warm ischemia and cold preservation in the absence of allogeneic response (isografts) and in the context of operational tolerance.

METHODS

Dark Agouti (DA) rat kidneys were transplanted into DA recipients (isografts) or Albino Surgery recipients (allografts) tolerized by two transfusions of DA blood, under cover of cyclosporin A. Grafts were subjected to minimal cold preservation or to 30 mins warm ischemia followed by 24 hrs cold preservation.

RESULTS

After an initial peak of renal dysfunction, serum creatinine concentration returned to normal in isografts and nonischemic allografts, but remained significantly elevated in ischemic allografts (P<0.0002) throughout 6 months follow-up. Both allograft groups developed proteinuria. At 6 months, ischemic isografts and nonischemic allografts demonstrated very mild tubular atrophy and interstitial fibrosis. Tubulointerstitial injury was significantly more severe in ischemic allografts (P<0.01 vs. nonischemic allografts) and was associated with increased infiltrating monocyte/macrophages and NK cells (P<0.05). Moderate glomerulosclerosis was a feature of both allograft groups (P<0.05).

CONCLUSIONS

The modified allogeneic response in operationally tolerant recipients acts in synergy with ischemia/reperfusion injury in the development of chronic damage. Strategies to limit or modify the initial ischemia/reperfusion injury may ameliorate chronic tubulointerstitial damage. Progressive glomerular damage and proteinuria in allografts may require other pharmacological intervention.

UW solution for hypothermic machine perfusion of warm ischemic kidneys

BACKGROUND

Donation of kidneys from non-heart beating donors (NHBD) is increasingly being used to expand the donor pool. Warm ischemic injury of these kidneys suffered at harvest results in DGF at transplantation. In this study, we used hypothermic continuous machine perfusion preservation to mitigate this injury using two available solutions.

METHODS

Dog kidneys (beagles) were exposed to 0, 60, or 75 min of in situ warm ischemia (37 degrees C), followed by 24 to 72 hr preservation by machine perfusion with Belzer MPS solution or the UW-solution (Viaspan). Auto-transplantation was performed with immediate contralateral nephrectomy. Survival and renal function (serum creatinine) were evaluated for up to 10 days posttransplant.

RESULTS

Both solutions were equally effective for 72 hr machine perfusion preservation of dog kidneys giving 100% survival with only minor renal injury. Both solutions were also equally effective for preservation of kidneys exposed to 60 min of warm ischemia. However, only the UW solution gave reliable preservation (86% survival vs. 25% survival) in kidneys exposed to 75 min of warm ischemia and 24 hr machine perfusion.

CONCLUSION

UW solution used with continuous hypothermic machine perfusion preservation can rescue canine kidneys from severe warm ischemic injury.

The nondirected living donor program: a model for cooperative donation, recovery and allocation of living donor kidneys

We describe an altruistic nondirected (ND) and live donor/deceased donor list exchange (LE) donor program administered by an organ procurement organization (OPO) in the Washington, DC area. Screening eliminated 25 donors (17 NE; 8 LE) from the 97 donor applications (62 ND; 35 LE) completed. Twenty-one donors (16 ND; 5 LE) failed to follow through with the psychiatric evaluation, which eliminated 13 donors (9 ND; 4 LE). Two donors dropped out and 12 (9 ND; 3 LE) were medically unsuitable after final clinical evaluation. Twenty donor procedures were performed (10 ND; 10 LE) with four pending (2 ND; 2 LE). This resulted in a modest 3-5% increase in the OPO-procured kidney organ pool. The average cold ischemia time of the grafts not transported between transplant centers was 205 +/- 66 min compared with 243 +/- 48 min for transported grafts. With no documented adverse outcomes, donors had a hospital stay of length 2.9 days and at home recuperation of 12.3 days. Three- and 6-month creatinines were 1.44 +/- 1.36 and 1.68 +/- 0.61 for grafts not transported between transplant centers, and 1.6 +/- 0.27 and 1.6 +/- 0.44 for transported grafts. An OPO-administered altruistic donor program can serve as a model for cooperative donation, recovery and allocation of living donor kidneys.