Liver Transplantation In Pigs Research Articles

Development of a Large Animal Model of Ischemia-free Liver Transplantation in Pigs.

In organ transplantation, ischemia, and reperfusion injury (IRI) is considered as an inevitable event and the major contributor to graft failure. Ischemia-free liver transplantation (IFLT) is a novel transplant procedure that can prevent IRI and provide better transplant outcomes. However, a large animal model of IFLT has not been reported. Therefore, we develop a new, reproducible, and stable model of IFLT in pigs for investigating mechanisms of IFLT in IRI. Ten pigs were subjected to IFLT or conventional liver transplantation (CLT). Donor livers in IFLT underwent 6-h continuous normothermic machine perfusion (NMP) throughout graft procurement, preservation, and implantation, whereas livers in CLT were subjected to 6-h cold storage before implantation. The early reperfusion injury was compared between the 2 groups. Continuous bile production, low lactate, and liver enzyme levels were observed during NMP in IFLT. All animals survived after liver transplantation. The posttransplant graft function was improved with IFLT when compared with CLT. Minimal histologic changes, fewer apoptotic hepatocytes, less sinusoidal endothelial cell injury, and proinflammatory cytokine (interleukin [IL]-1β, IL-6, and tumor necrosis factor-α) release after graft revascularization were documented in the IFLT group versus the CLT group. We report that the concept of IFLT is achievable in pigs. This innovation provides a potential strategy to investigate the mechanisms of IRI and provide better transplant outcomes for clinical practice.

Magnetic-assisted laparoscopic liver transplantation in swine

BackgroundAlthough laparoscopic technology has achieved rapid development in the surgical field, it has not been applied to liver transplantation, primarily because of difficulties associated with laparoscopic vascular anastomosis. In this study, we introduced a new magnetic-assisted vascular anastomosis technique and explored its application in laparoscopic liver transplantation in pigs. MethodsTwo sets of magnetic vascular anastomosis rings (MVARs) with different diameters were developed. One set was used for anastomosis of the suprahepatic vena cava (SHVC) and the other set was used for anastomosis of the infrahepatic vena cava (IHVC) and portal vein (PV). Six laparoscopic orthotopic liver transplantations were performed in pigs. Donor liver was obtained via open surgery. Hepatectomy was performed in the recipients through laparoscopic surgery. Anastomosis of the SHVC was performed using hand-assisted magnetic anastomosis, and the anastomosis of the IHVC and PV was performed by magnetic anastomosis with or without hand assistance. ResultsLiver transplants were successfully performed in five of the six cases. Postoperative ultrasonographic examination showed that the portal inflow was smooth. However, PV bending and blood flow obstruction occurred in one case because the MVARs were attached to each other. The durations of loading of MVAR in the laparoscope group and manual assistance group for IHVC and PV were 13 ± 5 vs. 5 ± 1 min (P < 0.01) and 10 ± 2 vs. 4 ± 1 min (P < 0.05), respectively. The durations of MVAR anastomosis in the laparoscope group and manual assistance group for IHVC and PV were 5 ± 1 vs. 1 ± 1 min (P < 0.01), and 5 ± 1 vs. 1 ± 1 min (P < 0.01), respectively. The anhepatic phase was 43 ± 4 min in the laparoscope group and 23 ± 2 min in the manual assistance group (P < 0.01). ConclusionsOur study showed that magnetic-assisted laparoscopic liver transplantation can be successfully carried out in pigs.

Bridging to Allotransplantation-Is Pig Liver Xenotransplantation the Best Option?

In the past 20 y, the number of patients in the United States who died while waiting for a human donor liver totaled >52 000. The median national wait time for patients with acute liver failure and the most urgent liver transplant listing was 7 d in 2018. The need for a clinical "bridge" to allotransplantation is clear. Current options for supporting patients with acute liver failure include artificial liver support devices, extracorporeal liver perfusion, and hepatocyte transplantation, all of which have shown mixed results with regard to survival benefit and are largely experimental. Progress in the transplantation of genetically engineered pig liver grafts in nonhuman primates has grown steadily, with survival of the pig graft extended to almost 1 mo in 2017. Further advances may justify consideration of a pig liver transplant as a clinical bridge to allotransplantation. We provide a brief history of pig liver xenotransplantation, summarize the most recent progress in pig-to-nonhuman primate liver transplantation models, and suggest criteria that may be considered for patient selection for a clinical trial of bridging by genetically engineered pig liver xenotransplantation to liver allotransplantation.

Ischemic postconditioning improves the outcome of organs from donors after cardiac death in a pig liver transplantation model and provides synergistic protection with hypothermic machine perfusion.

This study investigated whether ischemic postconditioning (IPO) improved the outcome of organs from donors after cardiac death and had a synergistic effect with hypothermic machine perfusion (HMP) in a pig liver transplantation model. A donor after cardiac death (DCD) model was developed in 48 healthy Bama miniature pigs randomly divided into four groups: simple cold storage group (SCS group), IPO group, HMP group, HMP-IPO group. The levels of serum alanine aminotransferase (ALT), total bilirubin, histopathological findings, apoptotic activity of hepatocytes, international normalized ratio (INR), tumor necrosis factor-α (TNF-α), and Malondialdehyde (MDA) were compared. All recipients in the SCS group died within 6h after transplantation. The livers of the recipients in the IPO had 50% survival on day 5. HMP allowed 83.3% survival and HMP-IPO allowed 100% survival. After reperfusion, the recipients in the IPO and HMP-IPO group had lower ALT and total bilirubin levels, less Suzuki score, less apoptosis, and less injury to hepatocytes and biliary ducts and attenuated inflammatory response and oxidative load. IPO improved the outcome of organs from donors after cardiac death and had a synergistic effect with HMP in the pig liver transplantation model.

Impact of Three Methods of Ischemic Preconditioning on Ischemia-Reperfusion Injury in a Pig Model of Liver Transplantation

Background Ischemic preconditioning (IPC), either direct (DIPC) or remote (RIPC), is a procedure aimed at reducing the harmful effects of ischemia-reperfusion (I/R) injury. Objectives To assess the local and systemic effects of DIPC, RIPC, and both combined, in the pig liver transplant model. Materials and methods Twenty-four pigs underwent orthotopic liver transplantation and were divided into 4 groups: control, direct donor preconditioning, indirect preconditioning at the recipient, and direct donor with indirect recipient preconditioning. The recorded parameters were: donor and recipient weight, graft-to-recipient weight ratio (GRWR), surgery time, warm and cold ischemia time, and intraoperative hemodynamic values. Blood samples were collected before native liver removal (BL) and at 0 h, 1 h, 3 h, 6 h, 12 h, 18 h, and 24 h post-reperfusion for the biochemical tests: aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), creatinine, BUN (blood urea nitrogen), lactate, total and direct bilirubin. Histopathological examination of liver, gut, kidney, and lung fragments were performed, as well as molecular analyses for expression of the apoptosis-related BAX (pro-apoptotic) and Bcl-XL (anti-apoptotic) genes, eNOS (endothelial nitric oxide synthase) gene, and IL-6 gene related to inflammatory ischemia-reperfusion injury, using real-time polymerase chain reaction (RT-PCR). Results There were no differences between the groups regarding biochemical and histopathological parameters. We found a reduced ratio between the expression of the BAX gene and Bcl-XL in the livers of animals with IPC versus the control group. Conclusions DIPC, RIPC or a combination of both, produce beneficial effects at the molecular level without biochemical or histological changes.

The effects of cell surface CD47 downregulation on ischaemia-reperfusion injury during pig liver transplantation.

This study aimed to investigate the effect of cell surface CD47 downregulation on ischaemia-reperfusion injury (IRI) during pig liver transplantation. Blood samples were collected from healthy miniature Bama pigs randomly and equally divided into CD47 antagonism (group A), without CD47 antagonism (group B) and a sham group (group C). Blood samples were collected from groups A and B at 0, 8 and 48hours after establishment of the new liver through an indwelling tube in the right internal jugular vein. Blood samples were collected at the same time points after liver dissociation from group C. The expression of interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) was detected by enzyme-linked immunosorbent assay (ELISA); CD47 expression was detected by Western blot; and liver function indices, including alanine aminotransferase (ALT) and aspartic transaminase (AST), were directly read by an automatic biochemical analyzer. The concentrations of both receptors in group A were significantly lower than groups B and C, at 8 and 48hours after establishment of blood flow. At 8 and 48hours in the new liver stage, the values of CD47 levels, ALT and AST in group A were significantly reduced compared to groups B and C (P<0.05). The levels of CD47 in the three groups were consistent with the trends of the aforementioned observation indicators. The liver functions of the recipients were significantly improved by reducing the release of the inflammatory mediators. This study provides new ideas and intervention approaches for the treatment of IRI in liver transplantation.

Normothermic Ex Vivo Liver Perfusion Prevents Intrahepatic Platelet Sequestration After Liver Transplantation

The detrimental role of platelets in sinusoidal endothelial cell (SEC) injury during liver transplantation (LT) has been previously addressed after static cold storage (SCS), however, it is currently unknown after normothermic ex vivo liver perfusion (NEVLP). Pig LT was performed with livers from heart-beating donors or donation after circulatory death (DCD) donors subjected to SCS or NEVLP (n = 5/group). All pigs except for 1 (DCD-SCS-group) survived 4 days. The heart-beating donor- and DCD-NEVLP-groups showed significantly lower aspartate transaminase-levels compared with the SCS-groups 3 hours post-LT (P = 0.006), on postoperative day (POD) 2 (P = 0.005), POD3 (P = 0.007), and on POD4 (P = 0.012). Post-LT total platelet count recovered faster in the NEVLP than in the SCS-groups at 12 hours (P = 0.023) and 24 hours (P = 0.0038). Intrahepatic sequestration of platelets was significantly higher in the SCS-groups 3 hours postreperfusion and correlated with severity of SEC injury. In both SCS-groups, levels of tumor growth factor-β were higher 3 hours post-LT, on POD1 and on POD3. Moreover, platelet factor 4 levels and platelet-derived extracellular vesicles were increased in the SCS-groups. Hyaluronic acid levels were significantly higher in the SCS-groups, indicating a higher grade of endothelial cell dysfunction. Platelet inhibition achieved by pretreatment with clopidogrel (n = 3) partly reversed the detrimental effects on SEC injury and therefore provided further evidence of the important role of platelets in ischemia/reperfusion injury and SEC injury. Normothermic perfusion of liver grafts before transplantation effectively reduced platelet aggregation and SEC injury, which translated into an improved posttransplant organ function.

Adding the oxygen carrier M101 to a cold-storage solution could be an alternative to HOPE for liver graft preservation.

Background & AimsHypothermic oxygenated machine perfusion (HOPE) is a promising technique for providing oxygen to the liver during graft preservation; however, because of associated logistical constraints, addition of an oxygen transporter to static cold-storage solutions (SCS) might be easier. M101 is marine worm haemoglobin that has been shown to improve kidney preservation in the clinic when added to SCS. This study evaluated the effects of the addition of M101 to SCS on the quality of pig liver graft preservation.MethodsPig liver grafts were preserved using SCS, HOPE, or SCS+M101, and the liver functions were compared during cold preservation and after orthotopic allotransplantation (OLT) in pigs.ResultsDuring preservation of the liver grafts, mitochondrial function, ATP synthesis, antioxidant capacities, and hepatocyte architecture were better preserved, and free radical production, antioxidant activities, and inflammatory mediators were lower, with HOPE or SCS+M101 than with SCS alone. However, after 1 h of preservation, liver functions with HOPE were superior to those with SCS+M101. After 6 h of preservation and OLT, blood levels of aspartate and alanine aminotransferases and lactate dehydrogenase increased with a peak effect at Day 1 post-transplant; values were similar with HOPE and SCS+M101, and were significantly lower than those in the SCS group. At Days 1 and 3, tumor necrosis factor α levels remained lower with HOPE and SCS+M101 vs. SCS. At Day 7, liver cell necrosis and inflammation were less marked in both oxygenated groups.ConclusionsWhen added to SCS, M101 effectively oxygenates liver grafts during preservation, preventing post-transplant injury; although graft performances are below those achieved with HOPE.Lay summaryWhen transported between donors and recipients, even cold-stored liver grafts need oxygen to maintain their viability. To provide them with oxygen, we added a marine worm super haemoglobin (M101) to the cold-storage solution UWCS. Using a pig liver transplant model, we revealed that livers cold stored with UWCS+M101 showed improved oxygenation compared with simple cold-storage solutions, but did not reach the oxygenation level achieved with machine perfusion.

Continuous Resuscitation for Porcine Liver Transplantation From Donor After Cardiac Death

BackgroundTo solve the serious donor shortage, the demand is increasing for developing a new method to use the marginal donors, including donors after cardiac death (DCD). Continuous machine perfusion from ex vivo to in situ is a novel technique to overcome warm ischemia during organ grafting as an ischemia-free transplantation. Herein, we tested orthotopic and heterotopic ischemia-free liver transplantation in pigs and evaluated the perfusion characteristics of DCD grafts from ex vivo preservation to implantation. Materials and MethodsThe demonstration of ischemia-free transplantation was conducted using both orthotopic and heterotopic transplantation models. Warm ischemia time (WIT) was set at 60 minutes or 120 minutes in the DCD models. Recipients were humanely killed 3 days after transplant. Flow rates of portal vein and hepatic artery were set to 0.06 to 0.15 mL/min/g and 0.04 to 0.06 mL/min/g for the liver weight ratio, respectively. ResultsUnder the stable perfusion rate by machine perfusion, the average hepatic artery pressure of the liver graft after a WIT of 120 minutes was approximately 80 mm Hg higher than after WIT of 60 minutes. The recipient with liver graft of WIT of 60 minutes could not survive overnight. In heterotopic model, the recipient with 1 hour DCD liver survived until humanely killed. ConclusionsThe results of pressure monitoring in our DCD liver graft model indicate that pressures are influenced not only by thrombus formation but also by postmortem rigidity at 2 hours after cardiac death.

Impact of Different Clinical Perfusates During Normothermic Ex Situ Liver Perfusion on Pig Liver Transplant Outcomes in a DCD Model.

Human albumin/dextran (HA-D), bovine-gelatin (BG), and packed red blood cells plus plasma have been used in European and North-American clinical trials of normothermic ex situ liver perfusion (NEsLP). We compared the effects of these perfusates in a porcine model during NEsLP and after transplantation. Porcine livers were retrieved 30 minutes after circulatory death. After 5 hours of NEsLP, grafts were transplanted. Three groups (n = 6) were assessed (HA-D vs BG vs whole blood [WB]). One group of static cold storage (SCS) was evaluated for comparison with the perfusion groups. Hemodynamic variables, liver and endothelial injury, and function were assessed during NEsLP and posttransplantation. Hepatic artery flow was higher since the beginning of NEsLP in the HA-D group (HA-D, 238 ± 90 mL/min vs BG, 97 ± 33 mL/min vs WB, 148 ± 49 mL/min; P = 0.01). Hyaluronic acid was lower in the HA-D at the end of perfusion (HA-D, 16.28 ± 7.59 ng/μL vs BG, 76.05 ± 15.30 ng/μL vs WB, 114 ± 46 ng/μL; P < 0.001). After transplant, aspartate aminotransferase was decreased in the HA-D group when compared with the rest of the groups (HA-D, 444 ± 226 IU/L vs BG, 1033 ± 694 IU/L vs WB, 616 ± 444 IU/L vs SCS, 2235 ± 1878 IU/L). At 5 hours after transplant, lactate was lower in the HA-D group (HA-D, 3.88 ± 1.49 mmol/L vs BG, 7.79 ± 2.68 mmol/L vs WB, 8.16 ± 3.86 mmol/L vs SCS, 9.06 ± 3.54 mmol/L; P = 0.04). International Normalized Ratio was improved in HA-D group compared to the rest of the groups (HA-D, 1.23 ± 0.30 vs BG, 1.63 ± 0.20 vs WB, 1.50 ± 0.31 vs SCS, 1.97 ± 1.55; P = 0.03) after transplantation. In contrast, BG displayed lower aspartate aminotransferase levels during NEsLP (HA-D, 183 ± 53 IU/L vs BG, 142 ± 52 IU/L vs WB, 285 ± 74 IU/L; P = 0.01) and less cleaved-caspase-3 staining (HA-D, 2.05 ± 0.73% vs BG, 0.95 ± 1.14% vs WB, 1.74 ± 0.54% vs SCS, 7.95 ± 2.38%) compared with the other groups. On the other hand, the bile from the WB showed higher pH (HA-D, 7.54 ± 0.11 vs BG, 7.34 ± 0.37 vs WB, 7.59 ± 0.18) and lower glucose levels (HA-D, 0.38 ± 0.75 mmol/L vs BG, 1.42 ± 1.75 mmol/L vs WB, 0 ± 0 mmol/L) by the end of perfusion. Overall HA-D displayed more physiologic conditions during NEsLP that were reflected in less graft injury and improved liver function and survival after transplantation. Optimization of the perfusates based on the beneficial effects found with these different solutions would potentially improve further the outcomes through the use of NEsLP in marginal grafts.

Passive veno-venous bypass instead of centrifugal pump is feasible and low cost for experimental pig liver transplantation

Passive veno-venous bypass instead of centrifugal pump is feasible and low cost for experimental pig liver transplantation

Effect of the Selective NLRP3 Inflammasome Inhibitor mcc950 on Transplantation Outcome in a Pig Liver Transplantation Model With Organs From Donors After Circulatory Death Preserved by Hypothermic Machine Perfusion.

We investigated whether the outcome of organs from donors after circulatory death (DCD) can be improved by the addition of mcc950 to the perfusate of the hypothermic machine perfusion (HMP) system and intravenous mcc950 injection after transplantation in a pig liver transplantation model. Thirty-six healthy Bama mini pigs randomized into 3 groups. All the DCD livers were preserved in an HMP system after 2 hours of simple cold storage. In HMP-Postop group, mcc950 was added to the perfusate; in the control group and Postop group, the perfusate was normal LPS. After transplantation, the pigs in the Postop group and HMP-Postop group were intravenously administered 3 mg/kg mcc950, at the time of reperfusion and on day 2 and day 3 after transplantation. During the 3-day follow-up period, general operative characteristics, and serological markers and histological features related to ischemia reperfusion injury were examined. The HMP-Postop group suffer the lightest ischemia reperfusion injury (IRI), and functioned best after transplantation. Model for the Early Allograft Function Score (predictor of long-term survival), degree of injury in the hepatocytes and rate of apoptosis was lowest in the HMP-Postop group. Further, in the HMP-Postop group, the nucleotide-binding domain leucine-rich repeat containing family pyrin domain containing 3 inflammasome pathway activation was lowest, and the level of IL-1β was lowest. Postop group functioned better than control group, but not comparable with HMP-Postop group. The outcome of DCD organs can be improved by the addition of mcc950 to the perfusate of the HMP system and intravenous injection of mcc950 after transplantation.

Fabrication of a Novel Absorbable Vascular Anastomosis Device and Testing in a Pig Liver Transplantation Model.

An absorbable vascular anastomosis device (AVAD) was fabricated and tested in pig liver transplantation experiments. We prepared biodegradable copolymers with various ratios of L-lactide: glycolide and tested their properties including inherent viscosity, in vitro biodegradation, and tensile strength. The mechanical and physical properties of the finally selected copolymers were analyzed according to decomposition time. The AVAD, consisting of two inner rings and one coupler, was fabricated with 5-, 15-, and 20-mm diameter sizes using an injection molding machine. Based on changes in the overall mechanical and physical properties, it is believed that the AVAD will maintain its shape without deformation while connecting the blood vessels to external force for at least 3weeks. Four mini-pigs underwent liver transplantation with AVAD using livers obtained from swine leukocyte antigen-identical siblings. Anastomoses was achieved in all four cases. In case 4, an autopsy conducted at 4months revealed that the AVAD was absorbed and the anastomosis was intact, demonstrating the success of the AVAD in the pig liver transplantation experiments and the feasibility of using an AVAD in organ transplantation.

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.

Inducing Hepatitis C Virus Resistance After Pig Liver Transplantation-A Proof of Concept of Liver Graft Modification Using Warm Ex Vivo Perfusion.

Normothermic ex vivo liver perfusion (NEVLP) offers the potential to optimize graft function prior to liver transplantation (LT). Hepatitis C virus (HCV) is dependent on the presence of miRNA(microRNA)-122. Miravirsen, a locked-nucleic acid oligonucleotide, sequesters miR-122 and inhibits HCV replication. The aim of this study was to assess the efficacy of delivering miravirsen during NEVLP to inhibit miR-122 function in a pig LT model. Pig livers were treated with miravirsen during NEVLP or cold storage (CS). Miravirsen absorption, miR-122 sequestration, and miR-122 target gene derepression were determined before and after LT. The effect of miravirsen treatment on HCV infection of hepatoma cells was also assessed. NEVLP improved miravirsen uptake versus CS. Significant miR-122 sequestration and miR-122 target gene derepression were seen with NEVLP but not with CS. In vitro data confirmed miravirsen suppression of HCV replication after established infection and prevented HCV infection with pretreatment of cells, analogous to the pretreatment of grafts in the transplant setting. In conclusion, miravirsen delivery during NEVLP is a potential strategy to prevent HCV reinfection after LT. This is the first large-animal study to provide "proof of concept" for using NEVLP to modify and optimize liver grafts for transplantation.

Anti‐inflammatory signaling during ex vivo liver perfusion improves the preservation of pig liver grafts before transplantation

Normothermic ex vivo liver perfusion (NEVLP) improves graft preservation by avoiding cold ischemia injury. We investigated whether the protective effects of NEVLP can be further improved by applying strategies targeted on reducing the activation of proinflammatory cytokines during perfusion. Livers retrieved under heart-beating conditions were perfused for 4 hours. Following the preservation period, a pig liver transplantation was performed. In group 1 (n = 5), anti-inflammatory strategies (alprostadil, n-acetylcysteine, carbon monoxide, sevoflurane, and subnormothermic temperature [33°C]) were applied. This was compared with a perfused control group (group 2) where livers (n = 5) were perfused at 37°C without anti-inflammatory agents, similar to the setup used in current European clinical trials, and to a control group preserved with static cold storage (group 3). During 3-day follow-up, markers of reperfusion injury, bile duct injury, and liver function were examined. Aspartate aminotransferase (AST) levels during perfusion were significantly lower in the study versus control group at 1 hour (52 ± 6 versus 162 ± 86 U/L; P = 0.01), 2 hours (43 ± 5 versus 191 ± 111 U/L; P = 0.008), and 3 hours (24 ± 16 versus 218 ± 121 U/L; P = 0.009). During perfusion, group 1 versus group 2 had reduced interleukin (IL) 6, tumor necrosis factor α, and galactosidase levels and increased IL10 levels. After transplantation, group 1 had lower AST peak levels compared with group 2 and group 3 (1400 ± 653 versus 2097 ± 1071 versus 1747 ± 842 U/L; P = 0.47) without reaching significance. Bilirubin levels were significantly lower in group 1 versus group 2 at day 1 (3.6 ± 1.5 versus 6.60 ± 1.5 μmol/L; P = 0.02) and 3 (2 ± 1.1 versus 9.7 ± 7.6 μmol/L; P = 0.01). A trend toward decreased hyaluronic acid, as a marker of improved endothelial cell function, was observed at 1, 3, and 5 hours after reperfusion in group 1 versus group 2. Only 1 early death occurred in each group (80% survival). In conclusion, addition of anti-inflammatory strategies further improves warm perfused preservation. Liver Transplantation 22 1573-1583 2016 AASLD.

Pig Liver Xenotransplantation: A Review of Progress Toward the Clinic.

Experience with clinical liver xenotransplantation has largely involved the transplantation of livers from nonhuman primates. Experience with pig livers has been scarce. This brief review will be restricted to assessing the potential therapeutic impact of pig liver xenotransplantation in acute liver failure and the remaining barriers that currently do not justify clinical trials. A relatively new surgical technique of heterotopic pig liver xenotransplantation is described that might play a role in bridging a patient with acute liver failure until either the native liver recovers or a suitable liver allograft is obtained. Other topics discussed include the possible mechanisms for the development of the thrombocytopenis that rapidly occurs after pig liver xenotransplantation in a primate, the impact of pig complement on graft injury, the potential infectious risks, and potential physiologic incompatibilities between pig and human. There is cautious optimism that all of these problems can be overcome by judicious genetic manipulation of the pig. If liver graft survival could be achieved in the absence of thrombocytopenia or rejection for a period of even a few days, there may be a role for pig liver transplantation as a bridge to allotransplantation in carefully selected patients.

Protective role of normothermic machine perfusion during reduced-size liver transplantation in pigs.

The purpose of this study is to explore whether normothermic machine perfusion (NMP) preservation is superior to cold preservation during reduced-size liver transplantation (RSLT) in pigs. Twenty-four healthy Ba-Ma mini pigs were used (aged >13 months; weight 25-35 kg; regardless of sex). The animals were randomized into 2 groups. In group A (NMP), donor livers were harvested without warm ischemia time and heartbeats and then were connected to the NMP system to reduce the livers' size under the normothermic condition. In group B (University of Wisconsin [UW] solution), donor livers were harvested without warm ischemia time and heartbeats after being perfused by UW solution and were then preserved in 0°C-4°C UW solution to reduce the livers' size under cold conditions. After that, liver transplantation without venovenous bypass was performed. General RSLT information of the pigs from the 2 groups was recorded; the serological indices were measured; and routine pathological examination of liver tissue was observed. A significant difference was observed in the intraoperative bleeding between the 2 groups (P < 0.05), whereas no significant difference was found in the other indices (all P > 0.05). Significant differences of alanine aminotransferase levels, aspartate aminotransferase levels, and lactate dehydrogenase levels between the 2 groups were observed between postoperative days 3 and 5 (P < 0.05). Significant differences of lactic acid levels between the 2 groups were observed between postoperative days 2 and 5 (P < 0.05). Compared with the cold preservation group, the liver tissues of the NMP preservation group only rarely experienced liver cell necrosis and maintained integrities in the hepatic sinusoid spaces and endothelial cells. In conclusion, NMP preservation is superior to cold preservation during RSLT in pigs. Liver Transplantation 22 968-978 2016 AASLD.

Intermittent Subnormothermic Ex Vivo Liver Perfusion Reduces Endothelia Cell Death and Decreases Bile Duct Injury After Pig Liver Transplantation With DCD Grafts.

Intermittent Subnormothermic Ex Vivo Liver Perfusion Reduces Endothelia Cell Death and Decreases Bile Duct Injury After Pig Liver Transplantation With DCD Grafts.

Immediate graft histological assay, post pig's liver transplantation

To describe the vascular and tissue histopathological changes in seven sequential experimental liver transplantations in pigs. Fourteen female pigs, Sus domesticus species, with body mass between 5 and 8 kg were utilized. After the end of all anastomoses of the graft implantation in the receptor, the animal was monitored for 30 minutes, and at its end one of the biopsies was collected for histological analysis. The histological criteria utilized were: lytic hepatocyte necrosis, density of septal and portal inflammatory infiltrated, sinusoidal congestion and hemorrhage. The analysis was performed separately for the portal region in zone 1, 2 and 3. Among the structural changes undergone by the graft, those with greater frequency and intensity were vascular congestion and steatosis, which stood out in transplantations 5, 6 and 7. The technique demonstrated vascular alterations represented by vasocongestion, edema and minimum inflammatory reaction. In relation to the parenchyma, was observed macrovacuolar pan-acinar steatosis, focal lytic and occasional hemorrhages, beyond the accumulation of hemosiderin in Kuppfer's cells.