An Assessment of Urinary Biomarkers in a Series of Declined Human Kidneys Measured During ex-vivo Normothermic Kidney Perfusion

BACKGROUND: The measurement of urinary biomarkers during ex-vivo normothermic kidney perfusion (EVKP) may aid in the assessment of a kidney prior to transplantation. This study measured levels of neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1) and endothelin-1 (ET-1) during EVKP in a series of discarded human kidneys. METHODS: Fifty six kidneys from deceased donors were recruited into the study. Each kidney underwent 60 minutes of EVKP and was scored based on the macroscopic appearance, renal blood flow and urine output. The scores ranged from 1 (least injury) to 5 (most severe). Levels of oxygen consumption, extraction, creatinine fall and fractional excretion of sodium were measured during perfusion. Urinary levels of NGAL, KIM-1 and ET-1 were measured after EVKP. RESULTS: Thirty eight kidneys had an EVKP score of 1 or 2, 8 a score of 3 and 10 a score of 4 or 5. During EVKP lower levels of oxygen consumption, higher oxygen extraction, a lower decrement of serum creatinine and higher levels of NGAL and ET-1 were associated with a higher EVKP score (P<0.05). These parameters were also associated with a raised creatinine level in the donor before organ retrieval. Levels of KIM-1 were not associated with the perfusion parameters (P=0.649) or renal function in the donor (R=0.02458: P=0.271). CONCLUSION: The measurement of urinary biomarkers, particularly NGAL in combination with functional perfusion parameters and the EVKP score provides an informative measure of kidney quality which may aid the decision to transplant the kidney.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.This study was supported by Kidney Research UK. The research was also funded by the National Institute for Health Research Blood and Transplant Research Unit (NIHR BTRU) in Organ Donation and Transplantation at the University of Cambridge in collaboration with Newcastle University and in partnership with NHS Blood and Transplant (NHSBT)

Successful Transplantation of Human Kidneys Deemed Untransplantable but Resuscitated by Ex Vivo Normothermic Machine Perfusion

We report the successful transplantation of a pair of human kidneys that were declined for transplantation due to inadequate in situ perfusion but subsequently transplanted after perfusion and assessment using ex vivo normothermic perfusion (EVNP). The kidneys were from a 35-year-old man, a donation after circulatory death donor. Both kidneys were declined by all UK transplant centers. On arrival, the kidneys had significant areas of incomplete clearance of blood from the microcirculation that did not clear after a further attempt to flush them. Kidneys underwent 60 min of EVNP with an oxygenated packed red blood cell–based solution warmed to 35.2°C. During EVNP, the patchy areas cleared in both kidneys. The mean renal blood flow and total urine output were 68.0 mL/min/100 g and 560 mL in the left kidney and 59.9 mL/min/100 g, 430 mL in the right, respectively. Based on the EVNP perfusion parameters, both kidneys were deemed suitable for transplantation. They were transplanted without any complications, and both recipients had initial graft function. The serum creatinine levels at 3 months were 1.2 mg/dl in the recipient of the left kidney and 1.62 mg/dl in the recipient of the right kidney. EVNP technology can be used to assess and rescue kidneys previously deemed unsuitable for transplantation.This study was supported by Kidney Research UK. The research was also funded by the National Institute for Health Research Blood and Transplant Research Unit (NIHR BTRU) in Organ Donation and Transplantation at the University of Cambridge in collaboration with Newcastle University and in partnership with NHS Blood and Transplant (NHSBT). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR, the Department of Health, or NHSBT

Normothermic machine perfusion for the assessment and transplantation of declined human kidneys from donation after circulatory death donors.

BACKGROUND: A significant proportion of donation after circulatory death (DCD) kidneys are declined for transplantation because of concerns over their quality. Ex vivo normothermic machine perfusion (NMP) provides a unique opportunity to assess the quality of a kidney and determine its suitability for transplantation. METHODS: In phase 1 of this study, declined human DCD kidneys underwent NMP assessment for 60 min. Kidneys were graded 1-5 using a quality assessment score (QAS) based on macroscopic perfusion, renal blood flow and urine output during NMP. In phase 2 of the study, declined DCD kidneys were assessed by NMP with an intention to transplant them. RESULTS: In phase 1, 18 of 42 DCD kidneys were declined owing to poor in situ perfusion. After NMP, 28 kidneys had a QAS of 1-3, and were considered suitable for transplantation. In phase 2, ten of 55 declined DCD kidneys underwent assessment by NMP. Eight kidneys had been declined because of poor in situ flushing in the donor and five of these were transplanted successfully. Four of the five kidneys had initial graft function. CONCLUSION: NMP technology can be used to increase the number of DCD kidney transplants by assessing their quality before transplantation

Ex-vivo normothermic perfusion in renal transplantation: past, present and future

$\textbf{PURPOSE OF REVIEW}$: Marginal donor kidneys make up a substantial proportion of transplanted kidneys. Nonetheless, they are more susceptible to injury during procurement and preservation. Normothermic perfusion is an alternative method of organ preservation that can be used to improve the quality, resuscitate, assess and potentially repair the organ. This review provides an up-to-date summary of the role of normothermic perfusion in renal transplantation and what we can expect in the future. $\textbf{RECENT FINDINGS}$: Normothermic perfusion has been demonstrated to be a feasible and well tolerated method of organ preservation in a series of extended criteria donor kidneys. Furthermore, normothermic perfusion can be used as a quality assessment tool for kidneys pretransplant. In the future, normothermic perfusion could be used to manipulate the organ using gene and stem cell therapies ameliorating renal function after injury. $\textbf{SUMMARY}$: In the last 5 years, normothermic perfusion has been translated from an experimental laboratory technique into clinical practice with promising results. Normothermic perfusion has demonstrated itself to be multifaceted in its application in renal transplantation. It may improve early graft function and can be used to assess the quality of the kidney before transplantation. The implications of these applications are crucial in maximizing the use of donor organs available in the perpetual climate of organ shortage

Advances in Hypothermic and Normothermic Perfusion in Kidney Transplantation

Hypothermic and normothermic machine perfusion in kidney transplantation are purported to exert a beneficial effect on post-transplant outcomes compared to the traditionally used method of static cold storage. Kidney perfusion techniques provide a window for organ reconditioning and quality assessment. However, how best to deliver these preservation methods or improve organ quality has not yet been conclusively defined. This review summarises the promising advances in machine perfusion science in recent years, which have the potential to further improve early graft function and prolong graft survival.</jats:p

Kidney perfusion: some like it hot others prefer to keep it cool.

Purpose of review: Machine perfusion technologies provide an opportunity for improved preservation, organ assessment, and resuscitation of damaged kidneys. This review summarizes the recent advances in hypothermic and normothermic kidney machine perfusion technologies. Recent findings: Modifications to the perfusion conditions with the addition of oxygen during hypothermic machine perfusion can support a low level of metabolism, which in experimental settings improves graft function. Normothermic machine perfusion technologies are evolving in different directions including short-duration resuscitation, more prolonged periods of perfusion, and the transition between hypothermic and normothermic conditions. Clinical trials are ongoing in both hypothermic and normothermic settings. Functional parameters can be used to assess kidney quality and although normothermic machine perfusion may hold an advantage over hypothermic machine perfusion, new metabolomic, proteomic, and genomic technologies may be applied in the future to both technologies to provide more rigorous information on kidney quality. Promoting recovery by introducing an intervention during perfusion is an attractive area of research and therapies targeting the endothelium are a particular area of interest. Summary: A great deal of research is still needed to optimize and logistically place hypothermic and normothermic perfusion technologies. In the future, we may progress toward organ-tailored preservation whereby high-risk kidneys can undergo assessment and repair before transplantation.The research was supported by the National Institute for Health Research Blood and Transplant Research Unit (NIHR BTRU) in Organ Donation and Transplantation at the University of Cambridge in collaboration with Newcastle University and in partnership with NHS Blood and Transplant (NHSBT)

Response to "Past, Present, and Future of Dynamic Kidney and Liver Preservation and Resuscitation"

We are writing in response to the article written by Jochmans et al [1]. The article is a comprehensive review on the status of preservation and resuscitation techniques in kidney and liver transplantation. It highlights the need for dynamic techniques of preservation for higher-risk kidney and liver grafts, detailing hypothermic and normothermic perfusion technologies. The review also documents a list of registered clinical trials of these novel techniques in kidney transplantation. The supporting information (S1) also lists the planned or ongoing trials that are unregistered. The authors state that, currently, there are no registered ongoing clinical trials comparing preimplantation normothermic machine perfusion with static cold storage

Pharmacologic targeting of renal ischemia-reperfusion injury using a normothermic machine perfusion platform.

Normothermic machine perfusion (NMP) is an emerging modality for kidney preservation prior to transplantation. NMP may allow directed pharmacomodulation of renal ischemia-reperfusion injury (IRI) without the need for systemic donor/recipient therapies. Three proven anti-IRI agents not in widespread clinical use, CD47-blocking antibody (αCD47Ab), soluble complement receptor 1 (sCR1), and recombinant thrombomodulin (rTM), were compared in a murine model of kidney IRI. The most effective agent was then utilized in a custom NMP circuit for the treatment of isolated porcine kidneys, ascertaining the impact of the drug on perfusion and IRI-related parameters. αCD47Ab conferred the greatest protection against IRI in mice after 24 hours. αCD47Ab was therefore chosen as the candidate agent for addition to the NMP circuit. CD47 receptor binding was demonstrated by immunofluorescence. Renal perfusion/flow improved with CD47 blockade, with a corresponding reduction in oxidative stress and histologic damage compared to untreated NMP kidneys. Tubular and glomerular functional parameters were not significantly impacted by αCD47Ab treatment during NMP. In a murine renal IRI model, αCD47Ab was confirmed as a superior anti-IRI agent compared to therapies targeting other pathways. NMP enabled effective, direct delivery of this drug to porcine kidneys, although further efficacy needs to be proven in the transplantation setting