Kidney Preservation: Review of Present and Future Perspective

The impact of preservation solutions for static cold storage on kidney transplantation outcomes: Results of a Brazilian nationwide multicenter study

This study evaluated the current practices of selecting cold storage preservation solutions in Brazil and their impact on delayed graft function (DGF) incidence and 1-year outcomes in kidney transplant recipients. A retrospective cohort study was conducted, including 3,134 brain-dead deceased donor kidney transplants performed between 2014 and 2015 in 18 Brazilian centers. The most commonly used preservation solution was Euro-collins (EC, 55.4%), followed by Histidine-tryptophan-ketoglutarate (HTK, 30%) and Institut Georges Lopez (IGL-1, 14.6%). The incidence of DGF was 54.4%, with 11.7% of patients requiring dialysis for more than 14 days, indicating prolonged DGF. Upon adjusting for confounding variables, HTK demonstrated a significantly lower risk of DGF than EC (OR 0.7350.82500.926), as did IGL-1 (OR 0.6050.7120.837). Similar protective effects were observed for prolonged DGF when comparing HTK (OR 0.4780.5990.749) and IGL-1 (OR 0.4780.6810.749) against EC. No significant association was found between preservation solutions and 1-year death-censored graft survival. In conclusion, EC was the most frequently used cold storage perfusion solution, demonstrating a higher incidence and duration of DGF compared with HTK and IGL-1, but with no impact on 1-year graft survival.

Delayed graft function post renal transplantation: a review on animal models and therapeutics

The incidence of end-stage renal disease (ESRD) has been increasing worldwide. Its treatment involves renal replacement therapy, either by dialyses or renal transplantation from a living or deceased donor. Although the initial mortality rates for patients on dialysis are comparable with kidney transplant recipients, the quality of life and long-term prognosis are greatly improved in transplanted patients. However, there is a large gap between availability and need for donor kidneys. This has led to the increase in the use of expanded kidney donor criteria. Allograft dysfunction immediately after transplant sets it up for many complications, such as acute rejection and shorter allograft survival. Delayed graft function (DGF) is one of the immediate posttransplant insults to the kidney allograft, which is increasing in prevalence due to efforts to maximize the available donor pool for kidneys and use of expanded kidney donor criteria. In this review, we discuss the risk factors for DGF, its implications for long-term allograft survival, animal models of DGF, and the therapeutic options currently under evaluation for prevention and management of DGF.

Chemodivergent Synthesis of Sulfonamide and Sulfones from N-Tosylhydrazones by Switching Catalyst and Temperature

A catalyst- and temperature-controlled selective synthesis of sulfonamide and sulfones from N-tosylhydrazones and MBH carbonates has been developed. The use of palladium catalysts exclusively leads to sulfonamide products at room temperature, whereas the selective synthesis of sulfones is dominant for a temperature-controlled coupling reaction without palladium catalysis. Importantly, the catalyst- or temperature-controlled reaction exhibits high nucleophilicity rather than carbene reactivity in these transformations.

Evaluation of Oxidative Stress and Metabolic Profile in a Preclinical Kidney Transplantation Model According to Different Preservation Modalities

This study addresses a joint nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopy approach to provide a platform for dynamic assessment of kidney viability and metabolism. On porcine kidney models, ROS production, oxidative damage kinetics, and metabolic changes occurring both during the period between organ retrieval and implantation and after kidney graft were examined. The 1H-NMR metabolic profile—valine, alanine, acetate, trimetylamine-N-oxide, glutathione, lactate, and the EPR oxidative stress—resulting from ischemia/reperfusion injury after preservation (8 h) by static cold storage (SCS) and ex vivo machine perfusion (HMP) methods were monitored. The functional recovery after transplantation (14 days) was evaluated by serum creatinine (SCr), oxidative stress (ROS), and damage (thiobarbituric-acid-reactive substances and protein carbonyl enzymatic) assessments. At 8 h of preservation storage, a significantly (p < 0.0001) higher ROS production was measured in the SCS vs. HMP group. Significantly higher concentration data (p < 0.05−0.0001) in HMP vs. SCS for all the monitored metabolites were found as well. The HMP group showed a better function recovery. The comparison of the areas under the SCr curves (AUC) returned a significantly smaller (−12.5 %) AUC in the HMP vs. SCS. EPR-ROS concentration (μmol·g−1) from bioptic kidney tissue samples were significantly lower in HMP vs. SCS. The same result was found for the NMR monitored metabolites: lactate: −59.76%, alanine: −43.17%; valine: −58.56%; and TMAO: −77.96%. No changes were observed in either group under light microscopy. In conclusion, a better and more rapid normalization of oxidative stress and functional recovery after transplantation were observed by HMP utilization.

Hypothermic Machine Perfusion of Kidney Transplant: A Mini-Review

Most kidney grafts are marginal and from deceased donors, which yield worse clinical outcomes. Hypothermic machine perfusion has created a paradigm shift in kidney preservation. This mini-review summarizes the main points of hypothermic machine perfusion of kidney transplants that should be known by any physician and surgeon involved with kidney transplantation. Specifically, this review explains a proposed mechanism of action of hypothermic machine perfusion of kidney transplants. This review also describes the clinical effectiveness of hypothermic machine perfusion and explains how to evaluate and predict graft functionality according to machine parameters and perfusate biomarkers. Finally, treatment options and the most recent studies on oxygenated hypothermic machine perfusion are mentioned.

The effect of IGL-1 preservation solution on outcome after kidney transplantation: A retrospective single-center analysis

Institut Georges Lopez-1 (IGL-1) solution is increasingly used for kidney preservation, although little information on outcomes is available. Outcomes of all deceased donor kidneys preserved by IGL-1, University of Wisconsin solution (UW), or histidine-tryptophan-ketoglutarate (HTK) and transplanted in our center (2000-2018) were analyzed. Multivariable analysis for delayed graft function (DGF), functional DGF, estimated glomerular filtration rate (eGFR, CKD-EPI equation), proteinuria, acute rejection, death-censored graft loss, and patient survival were performed. A double robust approach, consisting of propensity score weighting and correction for confounders, minimized the risk of bias. In total, 1943 transplants were included: 234 with IGL-1, 1046 with UW, and 663 with HTK. As IGL-1 was only introduced in 2014, a prespecified sensitivity analysis of 917 kidneys (2010-2018) was performed using the same statistical approach. After weighting, IGL-1 retained a higher proportion of kidneys donated after circulatory death (DCD). IGL-1 was not independently associated with any of the outcomes when compared to UW or HTK. Sensitivity analysis between 2010 and 2018 showed similar results. In this retrospective analysis, using robust methodology to reduce the risk of bias, IGL-1 preservation results in equal outcomes compared to UW or HTK, despite more DCD transplants in the IGL-1 group.

IGL-1 preservation solution in kidney and pancreas transplantation: A systematic review

We aimed to systematically review published data on the effectiveness of Institut Georges Lopez-1 (IGL-1) as a preservation solution for kidney and pancreas grafts. A systematic literature search of PubMed, Embase, Web of Science, and the Cochrane Library databases was performed. Human studies evaluating the effects of IGL-1 preservation solution in kidney and/or pancreas transplantation were included. Outcome data on kidney and pancreas graft function were extracted. Of 1513 unique articles identified via the search strategy, four articles could be included in the systematic review. Of these, two retrospective studies reported on the outcome of IGL-1 compared to University of Wisconsin (UW) solution in kidney transplantation. These show kidneys preserved in IGL-1 had improved early function (2 weeks post-transplant) compared to UW. Follow-up was limited to 1 year and showed similar graft and patient survival rates when reported. Two case series described acceptable early outcomes (up to 1 month) of simultaneous kidney pancreas transplantation after storage in IGL-1. As only four clinical papers were identified, we widened our search to include four eligible large animal studies. Three compared IGL-1 with UW in pig kidney transplant models with inconclusive or mildly positive results. One pig pancreas transplant study suggested better early outcome with IGL-1 compared to UW. Too few published data are available to allow any firm conclusions to be drawn on the effectiveness of IGL-1 as a preservation solution of kidney and pancreas grafts. The limited available data show satisfactory early outcomes though no medium to long-term outcomes have been described. Further well-designed clinical studies are needed.

Hypothermic Machine Perfusion's Protection on Porcine Kidney Graft Uncovers Greater Akt-Erk Phosphorylation

BACKGROUND

To investigate the potential mechanisms of hypothermic machine perfusion (HMP)'s beneficial effects on kidney graft over static cold storage (SCS) in vitro.

METHODS

Ten kidneys of 5 Bama miniature male pigs were paired into 2 groups: SCS group and HMP group. Preservation solutions were taken at 0, 1, 3, and 6 hours for the measurement of K⁺, Na⁺, Cl^-, blood urea nitrogen (BUN), creatinine (Cr), and lactate dehydrogenase (LDH) using the standard laboratory methods. Renal cortex were harvested at 6 hours for the following measurement: lactic acid (LD), adenosine triphosphate (ATP), malondialdehyde (MDA), neutrophil accumulation (MPO), interleukin-10 (IL-10), and transforming growth factor-β (TGF-β). Ischemia-induced apoptosis and the protein expression levels of total Akt, phospho-Akt, total Erk, and phospho-Erk were analyzed by Western blotting.

RESULTS

Almost all of the tested metabolites in preservation solutions were reduced with time in the HMP group. Levels of Na⁺, Cl^-, BUN, Cr, K⁺, and LDH were lower in the HMP group compared with the SCS group, with differences in the first 4 reaching statistical significance. HMP alleviated ATP degradation and LD accumulation, diminished the MDA (P < .05) and MPO (P = .227) levels, and greatly raised IL-10 and TGF-β (P < .05) expression. A marked decrease of proapoptotic and a large increase of antiapoptotic markers (P < .05) along with greatly raised Akt (P < .05) and Erk (P < .01) phosphorylation was observed in the kidney of the HMP group compared with the SCS group.

CONCLUSION

HMP's kidney graft protection involves inhibition of accumulation of toxic metabolites, oxidative damage, and apoptosis along with upregulation of the Akt and Erk signaling pathway.

Organ preservation: from the past to the future

Organ transplantation is the most effective therapy for patients with end-stage disease. Preservation solutions and techniques are crucial for donor organ quality, which is directly related to morbidity and survival after transplantation. Currently, static cold storage (SCS) is the standard method for organ preservation. However, preservation time with SCS is limited as prolonged cold storage increases the risk of early graft dysfunction that contributes to chronic complications. Furthermore, the growing demand for the use of marginal donor organs requires methods for organ assessment and repair. Machine perfusion has resurfaced and dominates current research on organ preservation. It is credited to its dynamic nature and physiological-like environment. The development of more sophisticated machine perfusion techniques and better perfusates may lead to organ repair/reconditioning. This review describes the history of organ preservation, summarizes the progresses that has been made to date, and discusses future directions for organ preservation.

Tissue conservation for transplantation

Pathophysiological changes that occur during ischemia and subsequent reperfusion cause damage to tissues procured for transplantation and also affect long-term allograft function and survival. The proper preservation of organs before transplantation is a must to limit these injuries as much as possible. For decades, static cold storage has been the gold standard for organ preservation, with mechanical perfusion developing as a promising alternative only recently. The current literature points to the need of developing dedicated preservation protocols for every organ, which in combination with other interventions such as ischemic preconditioning and therapeutic additives offer the possibility of improving organ preservation and extending it to multiple times its current duration. This review strives to present an overview of the current body of knowledge with regard to the preservation of organs and tissues destined for transplantation.

Impact of machine perfusion after long static cold storage on delayed graft function incidence and duration and time to hospital discharge

Delayed graft function (DGF) is very high in our center (70%-80%), and we usually receive a kidney for transplant after more than 22 hours of static cold ischemia time (CIT). Also, there is an inadequate care of the donors, contributing to a high rate of DGF. We decided to test whether machine perfusion (MP) after a CIT improved the outcome of our transplant patients. We analyzed the incidence of DGF, its duration, and the length of hospital stay (LOS) in patients who received a kidney preserved with MP after a CIT (hybrid perfusion-HP). We included 54 deceased donors kidneys preserved with HP transplanted from Feb/13 to Jul/14, and compared them to 101 kidney transplants preserved by static cold storage (CS) from Nov/08 to May/12. The median pumping time was 11 hours. DGF incidence was 61.1% vs 79.2% (P = .02), median DGF duration was 5 vs 11 days (P < .001), and median LOS was 13 vs 18 days (P < .011), for the HP compared to CS group. The observed reduction of DGF with machine perfusion did not occur in donors over 50 years old. In the multivariate analysis, risk factors for DGF, adjusted for CIT, were donor age (OR, 1.04; P = .005) and the absence of use of MP (OR, 1.54; P = .051). In conclusion, the use of HP contributed to faster recovery of renal function and to a shorter length of hospital stay.

Potential benefits of melatonin in organ transplantation: a review

Organ transplantation is a useful therapeutic tool for patients with end-stage organ failure; however, graft rejection is a major obstacle in terms of a successful treatment. Rejection is usually a consequence of a complex immunological and nonimmunological antigen-independent cascade of events, including free radical-mediated ischemia-reperfusion injury (IRI). To reduce the frequency of this outcome, continuing improvements in the efficacy of antirejection drugs are a top priority to enhance the long-term survival of transplant recipients. Melatonin (N-acetyl-5-methoxytryptamine) is a powerful antioxidant and ant-inflammatory agent synthesized from the essential amino acid l-tryptophan; it is produced by the pineal gland as well as by many other organs including ovary, testes, bone marrow, gut, placenta, and liver. Melatonin has proven to be a potentially useful therapeutic tool in the reduction of graft rejection. Its benefits are based on its direct actions as a free radical scavenger as well as its indirect antioxidative actions in the stimulation of the cellular antioxidant defense system. Moreover, it has significant anti-inflammatory activity. Melatonin has been found to improve the beneficial effects of preservation fluids when they are enriched with the indoleamine. This article reviews the experimental evidence that melatonin is useful in reducing graft failure, especially in cardiac, bone, otolaryngology, ovarian, testicular, lung, pancreas, kidney, and liver transplantation.

Short term ex vivo storage of kidneys cause progressive nuclear ploidy changes of renal tubular epitheliocytes

In renal transplantation, there has been considerable success, mainly in term of post-transplant graft function. However, upon closer scrutiny, it is known that severe dysfunction, including persistence of renal failure is seen after transplantation. The major condition that potentially cause significant lesion may be hypothesized to be related to the hypothermic approach to storage. To systematically examine these issues, we stored mammalian (sheep) kidneys in UWS at 4 °C for four different time points (0, 1, 3 and 6 hours). We obtained renal histological sections and examined tubular architecture as well as nuclear characteristics of tubular epitheliocytes. The results of our preliminary investigations suggest that there are temporal changes of tubular epitheliocytes, as well as genomic changes. These changes were also seen in tissues stored at room temperature. Our observations suggest the need for additional studies for redesigning of improvised storage solutions. Pilot studies using Celsior also revealed similar kind of nuclear changes, suggesting that storage conditions are contributory, including perfusion versus static conditions. The results may explain persistence of tubular injury several days after orthotopic transplantation, and may potentially be contributory to delayed graft function (DGF).

Preservation solutions for static cold storage of abdominal allografts: which is best?

PURPOSE OF REVIEW

To update the reader on the recent literature in liver, kidney, pancreas, and intestine static cold preservation, and to identify which solutions are most advantageous for each organ.

RECENT FINDINGS

The comparison of randomized trials of histidine-tryptophan-ketoglutarate (HTK), Celsior, and University of Wisconsin solutions has shown equivalent risk of delayed graft function after kidney transplantation. Similar outcomes have been observed after pancreas preservation with University of Wisconsin, HTK, and Celsior solution. In live-donor liver transplantation, University of Wisconsin and HTK solution have shown equivalent results, whereas in the recent trials of deceased-donor liver transplantation, University of Wisconsin, HTK, and Celsior solutions have shown equivalence. Contrary to the most clinical trials, national registry data in kidney, pancreas, and liver transplantation demonstrate more detrimental effects and earlier graft loss after preservation with HTK versus University of Wisconsin solution. Early outcomes after intestinal transplantation with University of Wisconsin or HTK solution have shown no significant difference and animal studies indicate intraluminal preservation may be beneficial.

SUMMARY

The University of Wisconsin solution is the standard criterion static cold preservation for the procurement of liver, kidney, pancreas, and intestine. University of Wisconsin, HTK, and Celsior solutions all provide similar allograft outcomes in most clinical trials, but subtle differences have become more apparent in the recent studies and registry reports.

Ex-vivo perfusion machines in kidney transplantation. The significance of the resistivity index

Introduction

With a growing shortage of organs for transplantation, finding ways of increasing the donor organ pool remains of utmost importance. Perfusion machines (PM) have been proven to enhance the potential for kidney transplants to function sooner, last longer, giving patients the opportunity for a better life quality.

Objective

The aim of this study is to evaluate the relation between the resistance index provided by the PM, the postoperative resistance index measured by Doppler ultrasound and the initial graft outcome.

Material and method

Between January 2012-December 2012, clinical data obtained from 82 consecutive renal transplants from brain death donors (BDD) which underwent PM maintenance were analyzed in a transversal study. Prior transplantation we recorded the solution temperature, filtration rate and the resistance index provided by PM. After the surgical intervention, each patient had standard follow-up. Doppler ultrasound resistivity index (RI) was recorded on the first postoperative day.

Results

Out of 115 renal transplants, 98 (85.21%) were performed with grafts from BDD. The PM was used for 82 renal grafts. The Doppler resistance index in relation to the resistance index shows a highly statistical correlation by linear regression (R=0.813, p<0.0001). Primary graft function was recorded in 74 patients (90.24%) and it was highly statistically significant correlated with the resistance index measured by PM. Out of 8 patients with primary non-function, 6 patients recovered with normal graft function at one year.

Conclusion

The resistivity index recorded by the life-port machine is correlated with the vascular resistivity index measured by Doppler ultrasound and thus it may predicts the primary graft outcome.