Normothermic Machine Perfusion Group Research Articles

Twelve-hour normothermic liver perfusion in a rat model: characterization of the changes in the ex-situ bio-molecular phenotype and metabolism

The partial understanding of the biological events that occur during normothermic machine perfusion (NMP) and particularly during prolonged perfusion might hinder its deployment in clinical transplantation. The aim of our study was to implement a rat model of prolonged NMP to characterize the bio-molecular phenotype and metabolism of the perfused organs. Livers (n = 5/group) were procured and underwent 4 h (NMP4h) or 12 h (NMP12h) NMP, respectively, using a perfusion fluid supplemented with an acellular oxygen carrier. Organs that were not exposed to any procedure served as controls (Native). All perfused organs met clinically derived viability criteria at the end of NMP. Factors related to stress-response and survival were increased after prolonged perfusion. No signs of oxidative damage were detected in both NMP groups. Evaluation of metabolite profiles showed preserved mitochondrial function, activation of Cori cycle, induction of lipolysis, acetogenesis and ketogenesis in livers exposed to 12 h-NMP. Increased concentrations of metabolites involved in glycogen synthesis, glucuronidation, bile acid conjugation, and antioxidant response were likewise observed. In conclusion, our NMP12h model was able to sustain liver viability and function, thereby deeply changing cell homeostasis to maintain a newly developed equilibrium. Our findings provide valuable information for the implementation of optimized protocols for prolonged NMP.

Addition of a liver to the normothermic perfusion circuit reduces renal pro-inflammatory factors.

Normothermic machine perfusion (NMP) provides a novel platform to preserve isolated organs in an artificial condition. Our study aimed to explore the interaction between the liver and kidney at an ex vivo organ level by adding a liver to the kidney NMP circuit. Porcine kidney and liver obtained from abattoir were subjected to 9 h NMP after suffering 30-min warm ischemia time and 90-min cold ischemia time. The liver-kidney NMP group (n = 5) and the single-kidney NMP group (n = 5) were designed. During the NMP, perfusion parameters, blood gas analysis, and tissue samples were compared. The perfusate of both groups remained stable, and continuous urine production was observed during NMP. In the liver-kidney NMP group, the lactate level was low, while blood urea nitrogen increased and glucose levels decreased. After the NMP, the renal tissue in the liver-kidney group exhibited fewer histological changes such as tubular epithelium vacuolization, along with reduced expression of IL-6, IL-8, IL-1β, NLRP3, and GSDMD. Our results indicated that the expression of renal pro-inflammatory factors was reduced in the liver-kidney NMP system.

Study on the preservation effects of the amputated forelimb by machine perfusion at physiological temperature

PurposeIschemia and hypoxia are the main factors limiting limb replantation and transplantation. Static cold storage (SCS), a common preservation method for tissues and organs, can only prolong limb ischemia time to 4 – 6 h. The normothermic machine perfusion (NMP) is a promising method for the preservation of tissues and organs, which can extend the preservation time in vitro by providing continuous oxygen and nutrients. This study aimed to evaluate the difference in the efficacy of the 2 limb preservation methods. MethodsThe 6 forelimbs from beagle dogs were divided into 2 groups. In the SCS group (n = 3), the limbs were preserved in a sterile refrigerator at 4 °C for 24 h, and in the NMP group (n = 3), the perfusate prepared with autologous blood was used for the oxygenated machine perfusion at physiological temperature for 24 h, and the solution was changed every 6 h. The effects of limb storage were evaluated by weight gain, perfusate biochemical analysis, enzyme-linked immunosorbent assay, and histological analysis. All statistical analyses and graphs were performed using GraphPad Prism 9.0 one-way or two-way analysis of variance. The p value of less than 0.05 was considered to indicate statistical significance. ResultsIn the NMP group, the weight gained percentage was 11.72% ± 4.06%; the hypoxia-inducible factor-1α contents showed no significant changes; the shape of muscle fibers was normal; the gap between muscle fibers slightly increased, showing the intercellular distance of (30.19 ± 2.83) μm; and the vascular α-smooth muscle actin (α-SMA) contents were lower than those in the normal blood vessels. The creatine kinase level in the perfusate of the NMP group increased from the beginning of perfusion, decreased after each perfusate change, and remained stable at the end of perfusion showing a peak level of 4097.6 U/L. The lactate dehydrogenase level of the NMP group increased near the end of perfusion and reached the peak level of 374.4 U/L. In the SCS group, the percentage of weight gain was 0.18% ± 0.10%, and the contents of hypoxia-inducible factor-1α increased gradually and reached the maximum level of (164.85 ± 20.75) pg/mL at the end of the experiment. The muscle fibers lost their normal shape and the gap between muscle fibers increased, showing an intercellular distance of (41.66 ± 5.38) μm. The contents of vascular α-SMA were much lower in the SCS group as compared to normal blood vessels. ConclusionsNMP caused lesser muscle damage and contained more vascular α-SMA as compared to SCS. This study demonstrated that NMP of the amputated limb with perfusate solution based on autologous blood could maintain the physiological activities of the limb for at least 24 h.

Normothermic machine perfusion for older transplant recipients.

Elderly patients (≥65 years old) are increasingly undergoing liver transplantation and are more likely to be removed from the waitlist. Normothermic machine perfusion (NMP) holds promise in expanding the number of livers available for transplant and improving outcomes for marginal donors and recipients. We aimed to determine the impact of NMP on outcomes in elderly recipients at our institution and nationally using the UNOS database. The use of NMP on outcomes in elderly recipients was reviewed using both the UNOS/SRTR database (2016-2022) and institutional data (2018-2020). Characteristics and clinical outcomes were compared between the NMP and static cold (control) groups within both populations. Nationally, using the UNOS/SRTR database, we identified 165 elderly recipients from 28 centers who received a liver allograft undergoing NMP and 4270 that underwent traditional cold static storage. NMP donors were older (48.3 vs. 43.4 years, p< 0.01), had similar rates of steatosis (8.5% vs 8.5%, p= 0.58), were more likely to be from a DCD (41.8% vs 12.3%, p< 0.01), and had a higher donor risk index (DRI; 1.70 vs. 1.60, p< 0.02). NMP recipients had similar age but had a lower MELD score at transplant (17.9 vs. 20.7, p= 0.01). Despite increased marginality of the donor graft, NMP recipients had similar allograft survival and decreased length of stay, even after accounting for recipient characteristics including MELD. Institutional data showed that 10 elderly recipients underwent NMP and 68 underwent cold static storage. At our institution, NMP recipients had a similar length of stay, rates of complications, and readmissions. NMP may mitigate donor risk factors that are relative contraindications for transplantation in elderly liver recipients, increasing the donor pool. The application of NMP in older recipients should be considered.

Application of a novel artificial perfusate based on oxygen-carrying nanoparticles in normothermic machine perfusion for porcine liver preservation after cardiac death.

To investigate the efficacy of a novel artificial perfusate based on oxygen-carrying perfluoronaphthalene-albumin nanoparticles in normothermic machine perfusion (NMP) for preservation of porcine liver donation after cardiac death. Artificial perfusate with perfluoronaphthalene-albumin nanoparticles was prepared at 5% albumin (w/v) and its oxygen carrying capacity was calculated. The livers of 16 Landrace pigs were isolated after 1 h of warm ischemia, and then they were divided into 4 groups and preserved continuously for 24 h with different preservation methods: cold preservation with UW solution (SCS group), NMP preservation by whole blood (blood NMP group), NMP preservation by artificial perfusate without nanoparticles (non-nanoparticles NMP group) and NMP preservation by artificial perfusate containing nanoparticles (nanoparticles NMP group). Hemodynamics, tissue metabolism, biochemical indices of perfusate and bile were monitored every 4 h after the beginning of NMP. Liver tissue samples were collected for histological examination (HE and TUNEL staining) before preservation, 12 h and 24 h after preservation. The oxygen carrying capacity of nanoparticles in 100 mL artificial perfusate was 6.94 μL/mmHg (1 mmHg=0.133 kPa). The hepatic artery and portal vein resistance of nanoparticles NMP group and blood NMP group remained stable during perfusion, and the vascular resistance of nanoparticles NMP group was lower than that of blood NMP group. The concentration of lactic acid in the perfusate decreased to the normal range within 8 h in both nanoparticles NMP group and blood NMP group. There were no significant differences in accumulated bile production, alanine aminotransferase and aspartate aminotransferase in perfusate between nanoparticles NMP group and blood NMP group (all P>0.05). After 24 h perfusion, the histological Suzuki score in blood NMP group and nanoparticles NMP group was lower than that in SCS group and non-nanoparticles NMP group (all P<0.05), and the quantities of TUNEL staining positive cells in blood NMP group and non-nanoparticles NMP group was higher than those in nanoparticles NMP group and SCS group 12 h and 24 h after preservation (all P<0.05). Artificial perfusate based on oxygen-carrying nanoparticles can meet the oxygen supply requirements of porcine livers donation after cardiac death during NMP preservation, and it may has superiorities in improving tissue microcirculation and alleviating ischemia-reperfusion injury.

413.7: Normothermic Machine Perfusion Compared With Static Cold Storage of Liver Grafts for Late Liver Retransplantation: Results of the NAPLES Initiative

Introduction: The pool of donor organs available for patients undergoing liver retransplantation is small, due to the perceived need for an optimal graft. Strategies that can facilitate transplantation of suboptimal organs into retransplant candidates requires investigation. The aim of this study was to determine if patients undergoing liver retransplantation, can be safely transplanted with sub-optimal grafts following normothermic machine perfusion. Methods: Between November 2018 and November 2021, a prospectively enrolled group of retransplant candidates consented to receive livers with suboptimal features but preserved and viability tested with normothermic machine perfusion (NMP). Donor, graft and clinical outcomes were compared to a retrospective group that underwent retransplantation with a graft preserved via static cold storage (SCS) between January 2015 and November 2021. All recipients received grafts from deceased brain death donors. The primary outcome of this study was 6-month graft and patient survival. Results: During the study period, 37 patients underwent retransplantation with a NMP preserved graft. Three of these received two NMP preserved grafts. The CS control group comprised 54 patients, and two of these patients received two CS grafts. Therefore, the NMP and CS groups comprised 40 and 56 grafts respectively. Donor, graft, operative and outcome variables are displayed in table 1. The 6-month graft (90% v 86%. P=0.59) and patient (94% vs 93%, P=0.79) survival did not differ between groups (Table 1). This was despite the NMP group having significantly more steatotic grafts (Moderate steatosis; 30% vs 4%, P=<0.01), donors with transaminases >1000 IU/L (0% v 23%, P=<0.01), and grafts previously declined by at least one other transplant centre (78% v 26%, P=<0.01) (Table 1). The peak alanine transaminase in the initial post-operative 7 days was significantly lower (521 vs 796, P=0.02) in the NMP group, however the rate of early acute rejection was higher (50% vs 27%, P=0.02) but did not impact graft survival. Significantly higher rates of CVVH in the NMP group did not translate to a longer length of stay in ICU. Furthermore, longer term graft and patient survival did not differ between groups (Figure 1). Conclusion: This is the first study to demonstrate that NMP technology can be safely used for sub-optimal liver grafts, and these can be safely transplanted into patients that require retransplantation. This technology can therefore expand the graft options available to this high-risk group. Anne Fox Foundation, University Hospitals Birmingham Charity.

O006 A randomised trial of normothermic machine perfusion versus static cold storage in donation after circulatory death renal transplantation

Abstract Introduction Kidneys from donation after circulatory death (DCD) donors are more susceptible to cold storage (CS) injury and have a high risk of delayed graft function (DGF). This trial is the first to compare normothermic machine perfusion (NMP) to conventional CS in DCD kidney transplantation. Methods In a multicentre randomised control trial, DCD kidneys were randomised to either NMP or CS. NMP kidneys were perfused for 60min with an oxygenated red-cell-based solution (36.0°C) The primary end point was DGF defined as the requirement for dialysis in the first 7days post-transplant. Secondary outcome measures included renal function up to 12 months posttransplant and patient/ graft survival. For all outcome measures a logistic regression model was used adjusted for cold ischaemic time, donor age, left/right kidney and centre. Results February 2016-March 2020, 338 kidneys were randomised into the trial. Twenty-five kidneys did not undergo NMP due to logistical/technical difficulties but were included in an intention-to-treat analysis. Twenty-seven kidneys in the NMP and 21 in the CS group where not transplanted and excluded; 143 NMP and 147 CS kidneys were analysed. There was no significant difference in the rate of DGF (NMP 61% vs CS 58%; P=0.624). Secondary outcome measures demonstrated a significantly higher creatinine reduction ratio day 2(CRR2) (P=0.035) and significantly lower levels of serum creatinine across all timepoints in the NMP group (P=0.024). Conclusion A short end period of NMP did not reduce rates of DGF in DCD kidneys. Secondary outcome measures suggest that NMP may improve renal function. Take-home message This is the first randomised controlled trial of normothermic machine perfusion (NMP) in clinical transplantation. The results suggest that NMP may improve the renal function of DCD kidneys.

Transplantation of Extended Criteria Donor Livers Following Continuous Normothermic Machine Perfusion Without Recooling.

Background.Traditional liver transplant strategies with cold preservation usually result in ischemia-reperfusion injury (IRI) to the donor liver. Regular normothermic machine perfusion (NMP) donor livers suffer IRI twice. Here, we aimed to introduce a novel technique called continuous NMP without recooling to avoid a second IRI and its application in livers from extended criteria donors.Methods.Seven donor livers transplanted following continuous NMP without recooling, 7 donor livers transplanted following standard NMP, and 14 livers under static cold storage (SCS) were included in this study. Perioperative outcomes were recorded and analyzed between groups.Results.During the NMP without a recooling procedure, all livers cleared lactate quickly to normal levels in a median time of 100 min (interquartile range, 60–180) and remained stable until the end of perfusion. In the NMP without recooling and standard NMP groups, posttransplant peak aspartate aminotransferase and alanine aminotransferase levels were both significantly lower than those in the SCS group (P = 0.0015 and 0.016, respectively). The occurrence rate of early allograft dysfunction was significantly lower in the NMP without recooling group than in the SCS group (P = 0.022), whereas there was no difference in the NMP group with or without recooling (P = 0.462).ConclusionsOur pilot study revealed a novel technique designed to avoid secondary IRI. This novel technique is shown to have at least a comparable effect on the standard NMP, although more data are needed to show its superiority in the future.

Quantitative Metabolomics of Tissue, Perfusate, and Bile from Rat Livers Subjected to Normothermic Machine Perfusion.

Machine perfusion (MP) allows the maintenance of liver cells in a metabolically active state ex vivo and can potentially revert metabolic perturbations caused by donor warm ischemia, procurement, and static cold storage (SCS). The present preclinical research investigated the metabolic outcome of the MP procedure by analyzing rat liver tissue, bile, and perfusate samples by means of high-field (600 MHz) nuclear magnetic resonance (NMR) spectroscopy. An established rat model of normothermic MP (NMP) was used. Experiments were carried out with the addition of an oxygen carrier (OxC) to the perfusion fluid (OxC-NMP, n = 5) or without (h-NMP, n = 5). Bile and perfusate samples were collected throughout the procedure, while biopsies were only taken at the end of NMP. Two additional groups were: (1) Native, in which tissue or bile specimens were collected from rats in resting conditions; and (2) SCS, in which biopsies were taken from cold-stored livers. Generally, NMP groups showed a distinctive metabolomic signature in all the analyzed biological matrices. In particular, many of the differentially expressed metabolites were involved in mitochondrial biochemical pathways. Succinate, acetate, 3-hydroxybutyrate, creatine, and O-phosphocholine were deeply modulated in ex vivo perfused livers compared to both the Native and SCS groups. These novel results demonstrate a broad modulation of mitochondrial metabolism during NMP that exceeds energy production and redox balance maintenance.

Safety and feasibility of 2h of normothermic machine perfusion of donor kidneys in the Eurotransplant Senior Program.

BackgroundThe 5-year graft survival rate of donor kidneys transplanted in the Eurotransplant Senior Program (ESP) is only 47 per cent. Normothermic machine perfusion (NMP) may be a new preservation technique that improves graft outcome. This pilot study aimed to assess safety and feasibility of this technique within the ESP.MethodsRecipients were eligible for inclusion if they received a donor kidney within the ESP. Donor kidneys underwent 2 h of oxygenated NMP with a red cell-based solution at 37°C, additional to standard-of-care preservation (non-oxygenated hypothermic machine perfusion). The primary outcome was the safety and feasibility of NMP. As a secondary outcome, graft outcome was investigated and compared with that in a historical group of patients in the ESP and the contralateral kidneys.ResultsEleven patients were included in the NMP group; the function of eight kidneys could be compared with that of the contralateral kidney. Fifty-three patients in the ESP, transplanted consecutively between 2016 and 2018, were included as controls. No adverse events were noted, especially no arterial thrombosis or primary non-function of the transplants. After 120 min of oxygenated NMP, median flow increased from 117 (i.q.r. 80–126) to 215 (170–276) ml/min (P = 0.001). The incidence of immediate function was 64 per cent in the NMP group and 40 per cent in historical controls (P = 0.144). A significant difference in graft outcome was not observed.DiscussionThis pilot study showed NMP to be safe and feasible in kidneys transplanted in the ESP. A well powered study is warranted to confirm these results and investigate the potential advantages of NMP on graft outcome.

Additional Normothermic Machine Perfusion Versus Hypothermic Machine Perfusion in Suboptimal Donor Kidney Transplantation: Protocol of a Randomized, Controlled, Open-Label Trial.

Introduction:Ageing of the general population has led to an increase in the use of suboptimal kidneys from expanded criteria donation after brain death (ECD-DBD) and donation after circulatory death (DCD) donors. However, these kidneys have inferior graft outcomes and lower rates of immediate function. Normothermic machine perfusion (NMP) may improve outcomes of these suboptimal donor kidneys. Previous non-randomized studies have shown the safety of this technique and suggested its efficacy in improving the proportion of immediate functioning kidneys compared to static cold storage (SCS). However, its additional value to hypothermic machine perfusion (HMP), which has already been proved superior to SCS, has not yet been established.Methods and analysis:This single-center, open-label, randomized controlled trial aims to assess immediate kidney function after 120 minutes additional, end-ischemic NMP compared to HMP alone. Immediate kidney function is defined as no dialysis treatment in the first week after transplant. Eighty recipients on dialysis at the time of transplant who receive an ECD-DBD or DCD kidney graft are eligible for inclusion. In the NMP group, the donor kidney is taken of HMP upon arrival in the recipient hospital and thereafter put on NMP for 120 minutes at 37 degrees Celsius followed by transplantation. In the control group, donor kidneys stay on HMP until transplantation. The primary outcome is immediate kidney function.Ethics and dissemination:The protocol has been approved by the Medical Ethical Committee of Erasmus Medical Center (2020-0366). Results of this study will be submitted to peer-reviewed journals.Registration:registered in clinicaltrials.gov (NCT04882254).Highlights:This is the first RCT to compare additional NMP to HMP alone.Extensive sampling will offer in-depth analysis of kidney physiology during NMP.This RCT may help identify biomarkers to predict clinical outcomes during NMP.Biomarkers can help develop NMP as assessment tool for declined kidneys.

Making Every Liver Count: Increased Transplant Yield of Donor Livers Through Normothermic Machine Perfusion.

Normothermic machine perfusion (NMP) enables optimized ex-vivo preservation of a donor liver in a normal physiologic state. The impact of this emerging technology on donor liver utilization has yet to be assessed. NMP of the donor liver and ex-vivo enhancement of its function has been envisioned for decades, however only with recent technological advances have devices been suitable for transition to clinical practice. The present study examines the effect NMP on liver utilization in the United States. The United Network for Organ Sharing database was queried to identify deceased donor livers procured from 2016 to 2019 (n = 30596). Donor livers were divided by preservation method: standard cold-static preservation (COLD, n = 30,368) versus NMP (n = 228). Donor and recipient risk factors, liver disposition, and discard reasons were analyzed. The primary outcome was liver discard rate between 2 groups. A total of 4037 livers were discarded. The NMP group had a 3.5% discard rate versus 13.3% in the COLD group (P < 0.001), and this was despite NMP donors being older (47.7 vs 39.5 years, P < 0.0001), more frequently donation after cardiac death (DCD) (18% vs 7%, P < 0.001), and having a greater donor risk index (1.6 vs 1.5, P < 0.05). The most common reasons for liver discard in the COLD group were biopsy findings (38%), DCD warm ischemic time (11%), and prolonged preservation time (10%). Survival analysis, following propensity score matching, found no significant difference in 1-year overall survival between recipients of NMP versus COLD livers. NMP reduces the discard rate of procured livers despite its use in donors traditionally considered of more marginal quality. NMP maintains excellent graft and patient survival. Broader application of NMP technology holds the potential to generate a significant number of additional liver grafts for transplantation every year, thus greatly reducing the nationwide disparity between supply and demand.

RETRACTED ARTICLE: Heme oxygenase-1-modified bone marrow mesenchymal stem cells combined with normothermic machine perfusion to protect donation after circulatory death liver grafts

BackgroundDonation after circulatory death (DCD) liver grafts have a poor prognosis after transplantation. We investigated whether the outcome of DCD donor organs can be improved by heme oxygenase 1 (HO-1)-modified bone marrow-derived mesenchymal stem cells (BMMSCs) combined with normothermic machine perfusion (NMP), and explored its underlying mechanisms.MethodsBMMSCs were isolated, cultured, and transduced with the HO-1 gene. An NMP system was established. DCD rat livers were obtained, preserved by different methods, and the recipients were divided into 5 groups: sham operation, static cold storage (SCS), NMP, BMMSCs combined with NMP, and HO-1/BMMSCs combined with NMP (HBP) groups. Rats were sacrificed at 1, 7, and 14 days after surgery; their blood and liver tissue samples were collected; and liver enzyme and cytokine levels, liver histology, high-mobility group box 1 (HMGB1) levels in monocytes and liver tissues, and expression of Toll-like receptor 4 (TLR4) pathway-related molecules were evaluated.ResultsAfter liver transplantation, the SCS group showed significantly increased transaminase levels, liver tissue damage, and shorter survival time. The HBP group showed lower transaminase levels, intact liver morphology, prolonged survival time, and decreased serum and liver proinflammatory cytokine levels. In the NMP and SCS groups, HMGB1 expression in the serum, monocytes, and liver tissues and TLR4 pathway-related molecule expression were significantly decreased.ConclusionsHO-1/BMMSCs combined with NMP exerted protective effects on DCD donor liver and significantly improved recipient prognosis. The effect of HO-1/BMMSCs was greater than that of BMMSCs and was mediated via HMGB1 expression and TLR4 pathway inhibition.

Mesenchymal Stromal Cell Treatment of Kidneys During Normothermic Machine Perfusion is Safe and Feasible with Effective Traceability after Transplantation

Lohmann 1/M. Pool 2, K. Rozenberg 3, M. Eijken 4, U. Møldrup 5, B.K. Møller 6, J.M. Sierra Parraga 7, M. Hoogduijn 7, L. Lo Faro 3, C. Moers 2, J. Hunter 3, A.K. Keller 1, H. Leuvenink 2, C.C. Baan 7, R.J. Ploeg 3, B. Jespersen 1&#x0D; &#x0D; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark&#x0D; Department of Surgery, University Medical Center Groningen, Groningen, The Netherlands&#x0D; Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom&#x0D; Department of Renal Medicine, Aarhus University Hospital, Aarhus, Denmark&#x0D; Department of Urology, Aarhus University Hospital, Aarhus, Denmark&#x0D; Department of Clinical Immunology, Aarhus University Hospital, Aarhus, Denmark&#x0D; Department of Internal Medicine, Nephrology and Transplantation, Erasmus MC, University Medical Center, Rotterdam, the Netherlands&#x0D; &#x0D; Introduction&#x0D; Marginal kidneys are increasingly being accepted to decrease waiting time for a transplant. Normothermic machine perfusion (NMP) is a technique that allows delivery of therapies that may help condition or repair the organ prior to transplantation. Mesenchymal stromal cells (MSC) may be able to ameliorate ischaemia reperfusion injury as they possess potent anti-inflammatory and regenerative properties. We investigated the safety and effect of MSCs administered during ex vivo NMP prior to transplantation in a pig auto-transplant model of donation after circulatory death.&#x0D; Methods &#x0D; Porcine kidneys subjected to 75 min warm ischaemia were retrieved and preserved for 14h by oxygenated HMP (oxHMP) and 4h NMP and then auto-transplantation. Kidneys were randomised to three different intervention strategies (n=7 per group): following 1h NMP, either a vehicle (NMP), 10 million pig MSC (NMP+pMSC) or 10 million human MSC (NMP+hMSC) were intra-arterially infused. The NMP groups were all compared to a control group, where kidneys were only preserved with oxHMP. The pig was re-anaesthetised, the contralateral kidney was removed and the treated kidney was auto-transplanted and the animals were recovered for 14 days.&#x0D; Results&#x0D; Renal blood flow during NMP was no different between the groups (p=0.0685). Post-transplant plasma creatinine increased in all groups but there were no significant differences between the groups (p=0.517). Plasma kidney injury biomarker NGAL was significantly higher in the NMP+pMSC group compared to the NMP (p=0.003) and NMP+hMSC (p=0.017) groups at day 14. On day 14, mGFR significantly improved in the NMP group compared to the control (55 ± 3 vs 42 ± 12 ml/min, p=0.025). No differences in GFR were observed on day 14 in the other groups (NMP+pMSC, p=0.090 and NMP+hMSC, p=0.387). MSC were detectable in biopsies of MSC treated kidney after NMP and post-transplantation.&#x0D; Conclusion &#x0D; NMP alone improved renal graft function compared to oxHMP of DCD kidneys post-transplant. The method of MSC administration during NMP proved to be safe, however in this model MSC treatment did not improve renal function. Nevertheless viable MSC remained detectable in the transplanted kidney at postoperative day 14 which may have an effect on longer term outcomes.

Ex Situ Liver Machine Perfusion: The Impact of Fresh Frozen Plasma.

The primary aim of this single-center, phase 1 exploratory study was to investigate the safety, feasibility, and impact on intrahepatic hemodynamics of a fresh frozen plasma (FFP)-based perfusate in ex situ liver normothermic machine perfusion (NMP) preservation. Using an institutionally developed perfusion device, 21 livers (13 donations after brain death and 8 donations after circulatory death) were perfused for 3hours 21minutes to 7hours 52minutes and successfully transplanted. Outcomes were compared in a 1:4 ratio to historical control patients matched according to donor and recipient characteristics and preservation time. Perfused livers presented a very low resistance state with high flow during ex situ perfusion (arterial and portal flows 340±150 and 890±70mL/minute/kg liver, respectively). This hemodynamic state was maintained even after reperfusion as demonstrated by higher arterial flow observed in the NMP group compared with control patients (220±120 versus 160±80mL/minute/kg liver, P=0.03). The early allograft dysfunction (EAD) rate, peak alanine aminotransferase (ALT), and peak aspartate aminotransferase (AST) levels within 7 days after transplantation were lower in the NMP group compared with the control patients (EAD 19% versus 46%, P=0.02; peak ALT 363±318 versus 1021±999 U/L, P=0.001; peak AST 1357±1492 versus 2615±2541 U/L, P=0.001 of the NMP and control groups, respectively). No patient developed ischemic type biliary stricture. One patient died, and all other patients are alive and well at a follow-up of 12-35 months. No device-related adverse events were recorded. In conclusion, with this study, we showed that ex situ NMP of human livers can be performed safely and effectively using a noncommercial device and an FFP-based preservation solution. Future studies should further investigate the impact of an FFP-based perfusion solution on liver hemodynamics during ex situ normothermic machine preservation.

Pilot, Open, Randomized, Prospective Trial for Normothermic Machine Perfusion Evaluation in Liver Transplantation From Older Donors.

Ex situ normothermic machine perfusion (NMP) might minimize ischemia/reperfusion injury (IRI) of liver grafts. In this study, 20 primary liver transplantation recipients of older grafts (≥70years) were randomized 1:1 to NMP or cold storage (CS) groups. The primary study endpoint was to evaluate graft and patient survival at 6months posttransplantation. The secondary endpoint was to evaluate liver and bile duct biopsies; IRI by means of peak transaminases within 7 days after surgery; and incidence of biliary complications at month 6. Liver and bile duct biopsies were collected at bench surgery, end of ex situ NMP, and end of transplant surgery. Interleukin (IL) 6, IL10, and tumor necrosis factor α (TNF-α) perfusate concentrations were tested during NMP. All grafts were successfully transplanted. Median (interquartile range) posttransplant aspartate aminotransferase peak was 709 (371-1575) IU/L for NMP and 574 (377-1162) IU/L for CS (P=0.597). There was 1 hepatic artery thrombosis in the NMP group and 1 death in the CS group. In NMP, we observed high TNF-α perfusate levels, and these were inversely correlated with lactate (P<0.001). Electron microscopy showed decreased mitochondrial volume density and steatosis and an increased volume density of autophagic vacuoles at the end of transplantation in NMP versus CS patients (P<0.001). Use of NMP with older liver grafts is associated with histological evidence of reduced IRI, although the clinical benefit remains to be demonstrated.

Normothermic Machine Perfusion Protects Against Liver Ischemia-Reperfusion Injury During Reduced-Size Liver Transplantation in Pigs.

BackgroundNormothermic machine perfusion (NMP) preservation is superior to cold preservation during reduced-size liver transplantation (RSLT) in pigs. However, the mechanism of this protective effect has not been explained. We aimed to compare the effects of NMP preservation with that of cold preservation (CS) in protecting against ischemia-reperfusion injury (IRI) during RSLT in pigs.Material/MethodsTwenty-four healthy Bama miniature pigs were randomized into 2 groups: 1) the NMP group in which donor livers harvested without warm ischemia time and cardiac activity were connected to the NMP system to reduce liver size under normothermic conditions, and 2) the CS group in which donor livers harvested without warm ischemia time and cardiac activity were perfused using the University of Wisconsin (UW) solution and then preserved in the 0–4°C UW solution to reduce liver size under cold conditions. Livers were then transplanted without veno-venous bypass. Amounts of bile secretion for the NMP groups were recorded hourly. The serological indices were measured. Expressions of cytochrome C, caspase 3, and NF-κB p65 in liver tissue were observed.ResultsThe levels of bile secretions were gradually diminished from 16.50±2.66 mL/h before splitting to 6.35±1.24 mL/h after splitting. With the exception of TNF-α on postoperative day 2, overall, levels of TNF-α, IL-1, IL-6, and MDA were significantly lower in the NMP group versus CS group for all 5 days postoperatively. Finally, cytochrome C, caspase 3, and NF-κB p65 expressions were all significantly suppressed in the NMP group as compared with the CS group.ConclusionsMP preservation is superior to cold preservation in protecting against liver IRI during RSLT in pigs.

Combination of hypothermic oxygenated machine perfusion followed by normothermic machine perfusion optimises the reconditioning of marginal human donor livers

Background: The shortage of organs for transplantation requires acceptance of livers from marginal donors. Hypothermic oxygenated machine perfusion (HOPE) improves mitochondrial function decreasing oxidative injury during reperfusion. Normothermic machine perfusion (NMP) allows viability assessment and extended preservation. We aim to assess whether a combination of both techniques would merge benefits and increase the rescue rate of marginal organs. Methods: Ten discarded human livers were randomly allocated to two experimental groups: (1) NMP group, in which 5 organs were perfused at 37oC using an acellular oxygen carrier based perfusate for 6 hours; (2) HOPE+NMP group, in which 5 organs had 2 hours of HOPE at 10oC followed by 4 hours of NMP. Viability was assessed at the end of 6 hours perfusion using the lactate clearance criteria. Results: The HOPE phase decreased the mitochondria respiratory rate (oxygen uptake, p=0.043; pCO2 in the perfusate, p=0.040) and increased the median ATP content (p=0.016). This resulted in slower oxygen consumption during rewarming and decreased tissue expression of markers of oxidative injury (4-hydroxynonenal, p=0.008) and activation of the inflammatory cascade (Kupffer cells, p=0.016; Vascular Cell Adhesion Protein 1, p=0.050). Livers deemed non-viable at the end of the NMP had lower ATP levels (p=0.050) and higher lactate levels (p=0.020). All HOPE+NMP group livers were deemed viable compared with three (60%) in the NMP alone group (p=0.222). Conclusion: The combined protocol of HOPE+NMP together merged benefits of the techniques and increased the rescue rate of marginal livers into the pool of transplantable organs compared with NMP alone.

The Role of Normothermic Perfusion in Liver Transplantation (TRaNsIT Study): A Systematic Review of Preliminary Studies.

Introduction The success of liver transplantation has been limited by the unavailability of suitable donor livers. The current organ preservation technique, i.e., static cold storage (SCS), is not suitable for marginal organs. Alternatively, normothermic machine perfusion (NMP) promises to recreate the physiological environment and hence holds promise for the better organ preservation. The objective of this systematic review is to provide an overview of the safety, benefits, and insight into the other potential useful parameters of NMP in the liver preservation. Material and Methods We searched the current literature following registration in the International Prospective Register of Systematic Reviews (PROSPERO) with registration number CRD42018086034 for prospective trials comparing the role of NMP device to SCS in liver transplant by searching the PubMed, EMBASE, Cochrane, BIOSIS, Crossref, and Scopus databases and clinical trial registry. Results The literature search identified five prospective clinical trials (four being early phase single institutional and single randomized multi-institutional) comparing 187 donor livers on NMP device to 273 donor livers on SCS. The primary outcome of interest was to assess the safety and graft survival at day 30 after transplant following NMP of the donor liver. Secondary outcomes included were early allograft dysfunction (EAD) in the first seven days; serum measures of liver functions as bilirubin, aspartate aminotransferase (AST), alanine amino transferase (ALT), alkaline phosphatase (ALP), and international normalized ratio (INR) on days 1–7; major complications as defined by a Clavien-Dindo score ≥ 3; and patient and graft survival and biliary complications at six months. The peaked median AST level between days 1 and 7 in the five trials was 417–1252 U/L (range 84–15009 U/L) while on NMP and 839–1474 U/L (range 153–8786 U/L) in SCS group. The median bilirubin level on day 7 ranged within 25–79 µmol/L (range 8–344 µmol/l) and 30–47.53 µmol/l (range 9–340 µmol/l) in NMP and SCS groups, respectively. A single case of PNF was reported in NMP group in the randomized trial while none of the other preliminary studies reported any in either group. There was intertrial variability in EAD which ranged within 15–56% in NMP group while being within 23–37% in SCS group. Biliary complications observed in NMP group ranged from 0 to 20%. Single device malfunction was reported in randomized controlled trial leading to renouncement of transplant while none of the other trials reported any machine failure, although two user related device errors inadvertent were reported. Conclusion This review outlines that NMP not only demonstrated safety and efficacy but also provided the favourable environment of organ preservation, repair, and viability assessment to donor liver prior to the transplantation with low rate of posttransplantation complication as PNF, EAD, and biliary complication; however further studies are needed to broaden our horizon.

Combined liver-kidney perfusion enhances protective effects of normothermic perfusion on liver grafts from donation after cardiac death.

It has been shown that combined liver-kidney normothermic machine perfusion (NMP) is able to better maintain the circuit's biochemical milieu. Nevertheless, whether the combined perfusion is superior to liver perfusion alone in protecting livers from donation after circulatory death (DCD) is unclear. We aimed to test the hypothesis and explored the mechanisms. Livers from 15 DCD pig donors were subjected to either static cold storage (group A), liver-alone NMP (group B), or combined liver-kidney NMP (group C). Livers were preserved for 6 hours and reperfused ex vivo for 2 hours to simulate transplantation or were transplanted in situ. During perfusion, group C showed an improved acid-base and biochemical environment in the circuit over group B. After reperfusion, the architecture of the liver grafts was best preserved in group C, followed by group B, then group A, as shown by the histology and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling staining of both hepatocytes and biliary epithelium. Ki-67 staining showed substantial hepatocyte proliferation and biliary epithelial regeneration after perfusion in group B and group C. Group C produced more bile in the reperfusion phase than those in group A and group B, with more physiological bile composition and less severe biliary epithelium injury. Von Willebrand factor-positive endothelial cells and E-selectin expression decreased in both group B and group C. Combined liver-kidney NMP not only produced more adenosine triphosphate, protected the nitric oxide signaling pathway, but also diminished oxidative stress (high mobility group box-1 protein and 8-hydroxy-2-deoxy guanosine levels) and inflammatory cytokine (IL6 and IL8) release when compared with liver-alone NMP and CS. In addition, the 7-day survival rate of liver transplant recipients was higher in group C than that in groups A and B. In conclusion, combined liver-kidney NMP can better protect DCD livers from warm ischemia and reperfusion injury probably by maintaining the stability of the internal environment and by abolishing oxidative stress injury. Liver Transplantation 24 67-79 2018 AASLD.