Machine Perfusion Of Liver Grafts Research Articles

A Global Overview on the Evolution, Debate, and Research Output on Liver Transplant Perfusion Machines.

Machine perfusion of liver grafts has gained popularity for its abilities to preserve liver grafts,reduce cold storage damage, and evaluate graft viability before transplant. However, debate persists regarding the optimal solutions, logistics, and biomarkers for assessing graft quality. To shed light on the lengthy debates surrounding the use of machine perfusion in liver graft preservation,this study utilized bibliometric analysis to evaluate the status and development trends of main research areas. On December 10th, 2022, we conducted a literature search using the Web of Science database to identify articles related to liver machine perfusion. The search included only original studies and reviews and excluded meeting abstracts, letters, notes, editorials, short surveys, book chapters, and errata. We identified the number of citations and encompassed various aspects, such as annual trends, countries, institutions, authors, journals, and key words. We used VOSviewer version 1.6.18 to generate tables and figures. After manually removing irrelevant papers, we included 264 articles (89 reviews; remaining were original studies). The articles were cited 5743 times, averaging 21.92 per article. We found that the United Kingdom (n = 76) was the country that produced the most articles,followed by theUnited States (66 articles). Most papers in our search were published in Liver Transplantation (n = 31) and Transplantation (n = 16). Bibliometric analysis provided insights into debates and advancements in liver graft preservation using machine perfusion. The analysis showed leading countries and key research areas in the field. This overview serves as a valuable resource for researchers, offering a foundation for further exploration and guiding future investigations in the field of machine perfusion for liver graft preservation.

A Single Preservation Solution for Static Cold Storage and Hypothermic Oxygenated Perfusion of Marginal Liver Grafts: A Preclinical Study.

Hypothermic oxygenated perfusion (HOPE) improves outcomes of marginal liver grafts. However, to date, no preservation solution exists for both static cold storage (SCS) and HOPE. After 30 min of asystolic warm ischemia, porcine livers underwent 6 h of SCS followed by 2 h of HOPE. Liver grafts were either preserved with a single preservation solution (IGL2) designed for SCS and HOPE (IGL2-Machine Perfusion Solution [MPS] group, n = 6) or with the gold-standard University of Wisconsin designed for for SCS and Belzer MPS designed for HOPE (MPS group, n = 5). All liver grafts underwent warm reperfusion with whole autologous blood for 2 h, and surrogate markers of hepatic ischemia-reperfusion injury (IRI) were assessed in the hepatocyte, cholangiocyte, vascular, and immunological compartments. After 2 h of warm reperfusion, livers in the IGL2-MPS group showed no significant differences in transaminase release (aspartate aminotransferase: 65.58 versus 104.9 UI/L/100 g liver; P = 0.178), lactate clearance, and histological IRI compared with livers in the MPS group. There were no significant differences in biliary acid composition, bile production, and histological biliary IRI. Mitochondrial and endothelial damage was also not significantly different and resulted in similar hepatic inflammasome activation. This preclinical study shows that a novel IGL2 allows for the safe preservation of marginal liver grafts with SCS and HOPE. Hepatic IRI was comparable with the current gold standard of combining 2 different preservation solutions (University of Wisconsin + Belzer MPS). These data pave the way for a phase I first-in-human study and it is a first step toward tailored preservation solutions for machine perfusion of liver grafts.

Normothermic Machine Perfusion—Improving the Supply of Transplantable Livers for High-Risk Recipients

The effectiveness of liver transplantation to cure numerous diseases, alleviate suffering, and improve patient survival has led to an ever increasing demand. Improvements in preoperative management, surgical technique, and postoperative care have allowed increasingly complicated and high-risk patients to be safely transplanted. As a result, many patients are safely transplanted in the modern era that would have been considered untransplantable in times gone by. Despite this, more gains are possible as the science behind transplantation is increasingly understood. Normothermic machine perfusion of liver grafts builds on these gains further by increasing the safe use of grafts with suboptimal features, through objective assessment of both hepatocyte and cholangiocyte function. This technology can minimize cold ischemia, but prolong total preservation time, with particular benefits for suboptimal grafts and surgically challenging recipients. In addition to more physiological and favorable preservation conditions for grafts with risk factors for poor outcome, the extended preservation time benefits operative logistics by allowing a careful explant and complicated vascular reconstruction when presented with challenging surgical scenarios. This technology represents a significant advancement in graft preservation techniques and the transplant community must continue to incorporate this technology to ensure the benefits of liver transplant are maximized.

Outcomes of normothermic machine perfusion of liver grafts in repeat liver transplantation (NAPLES initiative).

Retransplantation candidates are disadvantaged owing to lack of good-quality liver grafts. Strategies that can facilitate transplantation of suboptimal grafts into retransplant candidates require investigation. The aim was to determine whether late liver retransplantation can be performed safely with suboptimal grafts, following normothermic machine perfusion. A prospectively enrolled group of patients who required liver retransplantation received a suboptimal graft preserved via normothermic machine perfusion. This group was compared with both historical and contemporaneous cohorts of patient who received grafts preserved by cold storage. The primary outcome was 6-month graft and patient survival. The normothermic machine perfusion group comprised 26 patients. The historical (cold storage 1) and contemporaneous (cold storage 2) groups comprised 31 and 25 patients respectively. The 6-month graft survival rate did not differ between groups (cold storage 1, 27 of 31, cold storage 2, 22 of 25; normothermic machine perfusion, 22 of 26; P = 0.934). This was despite the normothermic machine perfusion group having significantly more steatotic grafts (8 of 31, 7 of 25, and 14 of 26 respectively; P = 0.006) and grafts previously declined by at least one other transplant centre (5 of 31, 9 of 25, and 21 of 26; P < 0.001). In liver retransplantation, normothermic machine perfusion can safely expand graft options without compromising short-term outcomes.

The effect of end-ischaemic normothermic machine perfusion on donor hepatic artery endothelial integrity.

Ex vivo normothermic machine liver perfusion (NMLP) involves artificial cannulation of vessels and generation of flow pressures. This could lead to shear stress-induced endothelial damage, predisposing to vascular complications, or improved preservation of donor artery quality. This study aims to assess the spatial donor hepatic artery (HA) endothelial quality downstream of the cannulation site after end-ischaemic NMLP. Remnant HA segments from the coeliac trunk up to the gastroduodenal artery branching were obtained after NMLP (n = 15) and after static cold storage (SCS) preservation (n = 15). Specimens were fixed in 10% neutral buffered formalin and sectioned at pre-determined anatomical sites downstream of the coeliac trunk. CD31 immunohistostaining was used to assess endothelial integrity by a 5-point ordinal scale (grade 0: intact endothelial lining, grade 5: complete denudation). Endothelial integrity after SCS was used as a control for the state of the endothelium at commencement of NMP. In the SCS specimens, regardless of the anatomical site, near complete endothelial denudation was present throughout the HA (median scores 4.5-5). After NMLP, significantly less endothelial loss in the distal HA was present compared to SCS grafts (NMLP vs. SCS: median grade 3 vs. 4.5; p = 0.042). In NMLP specimens, near complete endothelial denudation was present at the cannulation site in all cases (median grade: 5), with significantly less loss of the endothelial lining the further from the cannulation site (proximal vs. distal, median grade 5 vs. 3; p = 0.005). Loss of endothelial lining throughout the HA after SCS and at the cannulation site after NMLP suggests extensive damage related to surgical handling and preservation injury. Gradual improved endothelial lining along more distal sites of the HA after NMLP indicates potential for re-endothelialisation. The regenerative effect of NMLP on artery quality seems to occur to a greater extent further from the cannulation site. Therefore, arterial cannulation for machine perfusion of liver grafts should ideally be as proximal as possible on the coeliac trunk or aortic patch, while the site of anastomosis should preferentially be attempted distal on the common HA.

Hypothermic Oxygenated Machine Perfusion of Liver Grafts: Preliminary Experience in a Single Center.

Background: The need to maximize the use of donor organs and the issue of ischemia-reperfusion injury led to the use of thermoregulated oxygenated machine perfusion that improves the function of liver graft prior to transplantation. Among these methods, the HOPE (hypothermic oxygenated perfusion) protocol shows significant benefits. The aim of the paper is to analyze the early experience in using such procedure in a high-volume liver transplantation center. Methods: Normal liver grafts with cold ischemia time â?¥6 hours, marginal grafts and discarded (beyond ECD criteria) grafts were perfused using HOPE. Our selection criteria for dual HOPE (hepatic artery and portal perfusion) were steatosis, at least 3 associated ECD criteria, and discarded grafts. The main criteria to establish graft improvement were the progressive increase of arterial and portal flows, with lactate under 3 mmol/L or, even if over this value, with a decreasing trend during perfusion. Results: Whole liver grafts harvested from 28 donors between February 2016 and June 2021 benefitted from HOPE: 9 otherwise discarded grafts were assessed and considered not fit for transplantation, while the other 19 were ECD or standard grafts that were subsequently transplanted. Dual HOPE was used in 8 out of the 19 procedures (42.1%). We obtained a significant increase of arterial and portal flow (p=0.005 and p=0.001, respectively). In recipients, significant improvement of AST, ALT, INR and lactate values were recorded (p 0.001, p 0.001, p 0.001, and p=0.05, respectively). The rate of major postoperative complications (Dindo-Clavien grade 3) after LT was 26.3%, while the rate of early graft dysfunction was 15.8%. No PRS or acute rejection was recorded. The postoperative mortality rate was 15.8%. After a median follow-up of 9.3 months (range 2-44), the late major complication rate was 15.8%, without mortality. Conclusion: Machine perfusion is nowadays part of current clinical practice. This way, marginal liver grafts (DCD, ECD-DBD) may be safely used for transplantation improving the outcome, thus effectively enhance the use of a persistent scarce pool of donors. For best results, we believe that both techniques of HOPE (mono and dual HOPE) should be used based on specific selection criteria.

Novel oxygenation technique for hypothermic machine perfusion of liver grafts: Validation in porcine Donation after Cardiac Death (DCD) liver model

BackgroundHypothermic oxygenated machine perfusion improves outcomes in Liver Transplantation, but application is limited as O2 is supplied by a stationary circuit. A novel technique of O2 “pre-charge” in a portable pump would broaden use and further mitigate ischemia damage from organ transport. MethodsPorcine DCD livers were randomized to static cold storage (SCS, n = 8) or hypothermic machine perfusion (HMP). HMP was stratified into HMP-O2 (n = 5), non-O2 open to air HMP-RA (n = 5), and non-O2 with sealed lids or no air HMP-NA (n = 5). HMP-O2 was “pre-charged” using 100% O2 delivered at 10 L/min over 15 min. Perfusate and tissue O2 tension (pO2), liver biopsies, and fluid chemistries were analyzed. Results“Pre-charge” achieves sustained tissue and perfusate pO2 vs others. HMP-O2 results in decreased markers of hepatocyte injury: ALT (p < 0.05) and LDH (p < 0.05), lower expression of CRP and higher expression of SOD1 vs SCS. This suggests decreased inflammation and improved ROS scavenging. Conclusions“Pre-charge” is an effective technique, which allows portability and transport without an O2 source and improves graft parameters.

Perfusate Analysis During Dual Hypothermic Oxygenated Machine Perfusion of Liver Grafts: Correlations With Donor Factors and Early Outcomes.

Liver graft viability assessment has long been considered a limit of hypothermic oxygenated machine perfusion (HOPE). Aim of this study was assessing correlations of easily available perfusate parameters (PP) (aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, glucose, lactate, and pH) with graft features and outcome. In the period October 2018-February 2020, perfusate samples were obtained every 30 minutes during 50 dual-HOPE (D-HOPE) procedures. Correlations of PP with graft factors, 90-day graft loss, early allograft dysfunction (EAD), L-GrAFT score, acute kidney injury, and comprehensive complication index were analyzed using Pearson coefficient, receiver-operating characteristics analysis and by univariable and multivariable regression. Median D-HOPE time was 122 minutes. All parameters were normalized to liver weight. Only macrovesicular steatosis (MaS) significantly impacted PP levels and slope. Grafts with ≥30% MaS exhibited significantly different PP values and slope. Graft loss and EAD rate were 2% (n = 1) and 26% (n = 13). All PP except lactate correlated with EAD, 90-minute alanine aminotransferase showing the highest area under the receiver-operating characteristics curve (0.84). However, at multivariable analysis, the only factor independently associated with EAD was MaS (odds ratio, 5.44; confidence interval, 1.05-28.21; P = 0.04). Ninety minutes lactate dehydrogenase had the strongest correlation with L-GrAFT (R = 0.70; P < 0.001). PP correlated poorly with comprehensive complication index and grades 2-3 acute kidney injury rate. PP were predictive of graft function after transplant, but their association with graft survival and clinical outcomes requires further evaluation. MaS influenced levels of PP and was the only independent predictor of EAD.

Hypothermic Oxygenated Machine Perfusion of Liver Grafts from Brain-Dead Donors

Hypothermic oxygenated machine perfusion (HOPE) was introduced in liver transplantation (LT) to mitigate ischemia-reperfusion injury. Available clinical data mainly concern LT with donors after circulatory-determined death, whereas data on brain-dead donors (DBD) are scarce. To assess the impact of end-ischemic HOPE in DBD LT, data on primary adult LTs performed between March 2016 and June 2018 were analyzed. HOPE was used in selected cases of donor age >80 years, apparent severe graft steatosis, or ischemia time ≥10 hours. Outcomes of HOPE-treated cases were compared with those after static cold storage. Propensity score matching (1:2) and Bayesian model averaging were used to overcome selection bias. During the study period, 25 (8.5%) out of 294 grafts were treated with HOPE. After matching, HOPE was associated with a lower severe post-reperfusion syndrome (PRS) rate (4% versus 20%, p = 0.13) and stage 2–3 acute kidney injury (AKI) (16% versus 42%, p = 0.046). Furthermore, Bayesian model averaging showed lower transaminases peak and a lower early allograft dysfunction (EAD) rate after HOPE. A steeper decline in arterial graft resistance throughout perfusion was associated with lower EAD rate. HOPE determines a significant reduction of ischemia reperfusion injury in DBD LT.

Improvement of Normothermic Ex Vivo Machine Perfusion of Rat Liver Grafts by Dialysis and Kupffer Cell Inhibition With Glycine

Normothermic ex vivo liver machine perfusion might be a superior preservation strategy for liver grafts from extended criteria donors. However, standardized small animal models are not available for basic research on machine perfusion of liver grafts. A laboratory-scaled perfusion system was developed consisting of a custom-made perfusion chamber, a pressure-controlled roller pump, and an oxygenator. Male Wistar rat livers were perfused via the portal vein for 6 hours using oxygenated culture medium supplemented with rat erythrocytes. A separate circuit was connected via a dialysis membrane to the main circuit for plasma volume expansion. Glycine was added to the flush solution, the perfusate, and the perfusion circuit. Portal pressure and transaminase release were stable over the perfusion period. Dialysis significantly decreased the potassium concentration of the perfusate and led to significantly higher bile and total urea production. Hematoxylin-eosin staining and immunostaining for single-stranded DNA and activated caspase 3 showed less sinusoidal dilatation and tissue damage in livers treated with dialysis and glycine. Although Kupffer cells were preserved, tumor necrosis factor α messenger RNA levels were significantly decreased by both treatments. For proof of concept, the optimized perfusion protocol was tested with donation after circulatory death (DCD) grafts, resulting in significantly lower transaminase release into the perfusate and preserved liver architecture compared with baseline perfusion. In conclusion, our laboratory-scaled normothermic portovenous ex vivo liver perfusion system enables rat liver preservation for 6 hours. Both dialysis and glycine treatment were shown to be synergistic for preservation of the integrity of normal and DCD liver grafts.

Functional Human Liver Preservation and Recovery by Means of Subnormothermic Machine Perfusion

There is currently a severe shortage of liver grafts available for transplantation. Novel organ preservation techniques are needed to expand the pool of donor livers. Machine perfusion of donor liver grafts is an alternative to traditional cold storage of livers and holds much promise as a modality to expand the donor organ pool. We have recently described the potential benefit of subnormothermic machine perfusion of human livers. Machine perfused livers showed improving function and restoration of tissue ATP levels. Additionally, machine perfusion of liver grafts at subnormothermic temperatures allows for objective assessment of the functionality and suitability of a liver for transplantation. In these ways a great many livers that were previously discarded due to their suboptimal quality can be rescued via the restorative effects of machine perfusion and utilized for transplantation. Here we describe this technique of subnormothermic machine perfusion in detail. Human liver grafts allocated for research are perfused via the hepatic artery and portal vein with an acellular oxygenated perfusate at 21 °C.

Functional human liver preservation and recovery by means of subnormothermic machine perfusion.

There is currently a severe shortage of liver grafts available for transplantation. Novel organ preservation techniques are needed to expand the pool of donor livers. Machine perfusion of donor liver grafts is an alternative to traditional cold storage of livers and holds much promise as a modality to expand the donor organ pool. We have recently described the potential benefit of subnormothermic machine perfusion of human livers. Machine perfused livers showed improving function and restoration of tissue ATP levels. Additionally, machine perfusion of liver grafts at subnormothermic temperatures allows for objective assessment of the functionality and suitability of a liver for transplantation. In these ways a great many livers that were previously discarded due to their suboptimal quality can be rescued via the restorative effects of machine perfusion and utilized for transplantation. Here we describe this technique of subnormothermic machine perfusion in detail. Human liver grafts allocated for research are perfused via the hepatic artery and portal vein with an acellular oxygenated perfusate at 21 °C.

MicroRNAs to assess warm ischemic injury during machine perfusion of liver grafts from circulatory death donors

MicroRNAs to assess warm ischemic injury during machine perfusion of liver grafts from circulatory death donors

MicroRNAs to Assess Warm Ischemic Injury During Machine Perfusion of Liver Grafts From Circulatory Death Donors.

MicroRNAs to Assess Warm Ischemic Injury During Machine Perfusion of Liver Grafts From Circulatory Death Donors.

Экспериментальная гипотермическая машинная перфузия трансплантатов печени раствором «Кустодиол» (HTK)

Экспериментальная гипотермическая машинная перфузия трансплантатов печени раствором «Кустодиол» (HTK)

To Perfuse or Not to Perfuse Kidneys Donated after Cardiac Death

To Perfuse or Not to Perfuse Kidneys Donated after Cardiac Death

Hypothermic machine perfusion of liver grafts for transplantation: Technical development in human discard and miniature swine models

Introduction Cold storage (CS) is the standard preservation technique for liver transplantation (LTx). Hypothermic machine perfusion (HMP) is an alternative preservation technique that provides a continuous supply of substrates and removes waste products. HMP improves early graft function in kidney transplantation, especially for marginal organs: To our knowledge there have been no reports HMP in human LTx. The aim of this study was to develop a reproducible technique for liver HMP prior to initiating a clinical trial. Methods For the discard protocol, between May 2001 and March 2002, 10 nontransplantable human livers were obtained. We designed a model of atraumatic, centrifugal HMP of the portal vein (PV) and hepatic artery (HA) via donor vascular conduit. Livers were perfused at 3°C to 5°C with Vasosol solution for 5 to 10 hours using a modified Medtronic Portable Bypass System. Perfusion variables (temp, flow, pressure) where recorded every 30 minutes. During the study, we also validated our techniques in an animal model. For the animal protocol; six swine were used as liver donors and randomized to 12 hours of CS in UW ( n = 3) or 12 hours of HMP using Vasosol solution ( n = 3). LTx was performed in six swine. Animals survived until postoperative day 5. Results For the discard protocol, mean HMP time was 6.7 ± 1.8 hours. Target flow was 0.7 mL/g liver/min. PV and HA pressure ranged from 3 to 5 and 12 to 18 mm Hg, respectively. All grafts were maintained at 3°C to 5°C during HMP. For the animal protocol, all recipients had good liver function and survived to postoperative day 5. AST and TBili were similar between CS and HMP. Conclusions Our method of liver HMP appears to be a safe and reliable method to preserve livers. A clinical trial is now underway to evaluate this technique in human LTx.

Usefulness of preservation by machine perfusion of liver grafts from non–heart-beating donors—a porcine model

Usefulness of preservation by machine perfusion of liver grafts from non–heart-beating donors—a porcine model