Liver Reperfusion Research Articles

Preservation of coagulation function by normothermic machine perfusion in liver transplant as evidenced by thromboelastography parameters.

The use of normothermic machine perfusion (NMP) over static cold storage in liver transplantation has been shown to reduce posttransplant risks of early allograft dysfunction, primary nonfunction, and ischemic cholangiopathy, and its increasing use has played a role in the expanded utilization of marginal livers. While studies have demonstrated improved clinical outcomes using NMP over static cold storage preservation, real-time intraoperative data reflecting the quality and viability of NMP livers is limited. This retrospective, single-center study compared NMP versus static cold storage livers in first-time recipients of liver transplants through the evaluation of synthetic coagulation function as measured by thromboelastography and conventional coagulation testing. Secondarily, transfusion utilization between the 2 cohorts was reviewed. One hundred eighty-six recipients of liver transplants receiving allografts from donors after circulatory death were included in the study, of which 99 (53%) allografts were preserved in static cold storage, and 87 (47%) allografts were placed on the TransMedics Organ Care System. Study findings showed NMP livers supported with the TransMedics Organ Care System were associated with increased synthetic coagulation function and less excess fibrinolysis in the postreperfusion period compared to static cold storage livers, and that these findings were better reflected in real-time with thromboelastography monitoring versus conventional coagulation testing. Following reperfusion, there was a significant decrease in the transfusion of blood products in the NMP group compared with that in the static cold storage group. Overall, we determined that the use of intraoperative thromboelastography can provide real-time data to assess one aspect of reperfusion liver quality and viability.

SYK promotes the formation of neutrophil extracellular traps by inducing PKM2 nuclear translocation and promoting STAT3 phosphorylation to exacerbate hepatic ischemia-reperfusion injury and tumor recurrence

BackgroundAt present, hepatic ischemia-reperfusion injury (IRI) is an important complication of partial hepatectomy and liver transplantation, and it is an important cause of poor prognosis. Spleen tyrosine kinase(SYK) plays an important role in a variety of signaling pathways in the liver, but its role in hepatic IRI is still unclear. This study aims to investigate the role and mechanism of SYK in hepatic IRI and tumor recurrence.MethodsWe first observed the activation of SYK in the liver of mice in response to hepatic IRI. Subsequently, Pharmacological inhibitions of SYK were used to evaluated the effect of SYK on neutrophil recruitment and NETosis, and further explored the effect of SYK on IRI and tumor recurrence.ResultsOur study shows that SYK is activated in response to hepatic IRI and aggravates liver injury. On the one hand, neutrophils SYK during the early stage of liver reperfusion increases neutrophil extracellular traps (NETs) production by promoting Pyruvate kinase M2(PKM2) nuclear translocation leading to upregulation of phosphorylated STAT3, thereby exacerbating liver inflammation and tumor recurrence. On the other hand, macrophages SYK can promote the recruitment of neutrophils and increase the activation of NLRP3 inflammasome and IL1β, which further promotes the formation of NETs.ConclusionsOur study demonstrates that neutrophil and macrophage SYK synergistically promote hepatic IRI and tumor recurrence, and SYK may be a potential target to improve postoperative hepatic IRI and tumor recurrence.

228.8: MLKL deficiency attenuated hepatocyte oxidative DNA damage by activating mitophagy to suppress macrophage cGAS-STING signaling during liver ischemia and reperfusion injury.

228.8: MLKL deficiency attenuated hepatocyte oxidative DNA damage by activating mitophagy to suppress macrophage cGAS-STING signaling during liver ischemia and reperfusion injury.

Serum from patients with cirrhosis undergoing liver transplantation induces permeability in human pulmonary microvascular endothelial cells ex vivo.

Patients with cirrhosis undergoing liver transplantation frequently exhibit systemic inflammation, coagulation derangements, and edema, indicating endothelial dysfunction. This syndrome may worsen after ischemia-reperfusion injury of the liver graft, coincident with organ dysfunction that worsens patient outcomes. Little is known about changes in endothelial permeability during liver transplantation. We hypothesized that sera from these patients would increase permeability in cultured human endothelial cells ex vivo. Adults with cirrhosis presenting for liver transplantation provided consent for blood collection during surgery. Sera were prepared at five time points spanning the entire operation. The barrier function of human pulmonary microvascular endothelial cells in culture was assessed by transendothelial resistance measured using the ECIS ZΘ system. Confluent cells from two different endothelial cell donors were stimulated with human serum from liver transplant patients. Pooled serum from healthy men and purified inflammatory agonists served as controls. The permeability response to serum was quantified as the area under the normalized resistance curve. Responses were compared between time points and analyzed for associations with clinical characteristics of liver transplant patients and their grafts. Liver transplant sera from all time points during surgery-induced permeability in both endothelial cell lines. The magnitude of permeability change was heterogeneous between patients, and there were differences in the effects of sera on the two endothelial cell lines. In one of the cell lines, the severity of liver disease was associated with greater permeability at the start of surgery. In the same cell line, serum collected 15 min after liver reperfusion induced significantly more permeability as compared to that collected at the start of surgery. Early postreperfusion sera from patients undergoing living donor transplants induced more permeability than sera from deceased donor transplants. Sera from two exemplary cases of patients on preoperative dialysis, and one patient with an unexpectedly long warm ischemia time of the liver graft, induced exaggerated and prolonged endothelial permeability. Serum from patients with cirrhosis undergoing liver transplantation induces permeability of cultured human pulmonary microvascular endothelial cells. Increased endothelial permeability during liver transplantation may contribute to organ injury and present a target for future therapeutics.

Oxygenated versus non-oxygenated flush out during deceased donor liver procurement: The first proof-of-concept study in humans.

Liver transplantation is used for treating end-stage liver disease, fulminant hepatitis, and oncological malignancies and organ shortage is a major limiting factor worldwide. The use of grafts based on extended donor criteria have become internationally accepted. Oxygenated machine perfusion technologies are the most recent advances in organ transplantation; however, it is only applied after a period of cold ischemia. Due to its high cost, we aimed to use a novel device, OxyFlush®, based on oxygenation of the preservation solution, applied during liver procurement targeting the maintenance of ATP during static cold storage (SCS). Twenty patients were randomly assigned to the OxyFlush or control group based on a 1:1 ratio. In the OxyFlush group, the perfusion solution was oxygenated with OxyFlush® device while the control group received a non-oxygenated solution. Liver and the common bile duct (CBD) biopsies were obtained at three different time points. The first was at the beginning of the procedure, the second during organ preparation, and the third after total liver reperfusion. Biopsies were analyzed, and adenosine triphosphate (ATP) levels and histological scores of the liver parenchyma and CBD were assessed. Postoperative laboratory tests were performed. OxyFlush® was able to maintain ATP levels during SCS and improved the damage caused by the lack of oxygen in the CBD. However, OxyFlush® did not affect laboratory test results and histological findings of the parenchyma. We present a novel low-cost device that is feasible and could represent a valuable tool in organ preservation during SCS.

Ginkgetin Pretreatment Reduces Inflammatory Response in DCD Donor Liver via JAK2/STAT3 Signaling Pathway.

BACKGROUND Ginkgetin inhibits growth of tumor cells, reducing blood lipids, and improving atherosclerosis, but the protective effect of ginkgetin in donation after cardiac death (DCD) livers is still unknown. The aim of this study was to determine whether pretreatment of DCD donor livers with ginkgetin can reduce inflammatory response through the JAK2/STAT3 signaling pathway. MATERIAL AND METHODS Twenty male Sprague-Dawley rats (200-250 g) were randomly divided into 4 groups: Sham, DCD, Ginkgetin (0.6 mg/kg) pretreatment 1 h before surgery, and Ginkgetin (0.6 mg/kg) plus broussonin E (0.3 mg/kg) (JAK2/STAT3 signaling agonist) pretreatment 1 h before surgery. Rat livers were subjected to 30 min warm ischemia and 24 h cold storage to simulate the preservation process of DCD donor livers, followed by normothermic machine perfusion for 1 h to simulate liver reperfusion in vivo. Liver tissues and perfusate samples were collected for further studies. RESULTS Ginkgetin pretreatment significantly decreased the values of ALT and AST (P<0.05), and improved histological alterations according to improved Suzuki's Score (P<0.05). Ginkgetin also inhibited the protein expression levels of p-JAK2/JAK2 and p-STAT3/STAT3 (P<0.05). Furthermore, ginkgetin pretreatment inhibited levels of interleukin-1β, interleukin-6 and tumor necrosis factor a (P<0.05) to suppress inflammatory response. In addition, broussonin E reversed the improvement of ginkgetin on DCD donor livers. CONCLUSIONS Ginkgetin can inhibit the inflammatory response through the JAK2/STAT3 signaling pathway to improve the quality of DCD donor livers.

Bile acids attenuate hepatic inflammation during ischemia/reperfusion injury

Background & AimsPersistent cholestasis has been associated with poor prognosis after orthotopic liver transplantation (OLT). In this study, we aimed to investigate how the accumulation of tauro-beta-muricholic acid (TβMCA), resulting from the reprogramming of bile acid (BA) metabolism during liver ischemia/reperfusion (IR) stress, attenuates liver inflammation. MethodsIngenuity Pathway Analysis (IPA) was performed using transcriptome data from a murine hepatic IR model. Three different models of hepatic IR (liver warm IR, bile duct separation-IR, common bile duct ligation-IR) were employed. We generated AAV-transfected mice and CD11b-DTR mice to assess the role of BAs in regulating the myeloid S1PR2-GSDMD axis. Hepatic BA levels were analyzed using targeted metabolomics. Finally, the correlation between the reprogramming of BA metabolism and hepatic S1PR2 levels was validated through RNA-seq of human OLT biopsies. ResultsWe found that BA metabolism underwent reprogramming in murine hepatocytes under IR stress, leading to increased synthesis of TβMCA, catalyzed by the enzyme CYP2C70. The levels of hepatic TβMCA were negatively correlated with the severity of hepatic inflammation, as indicated by the serum IL-1β levels. Inhibition of hepatic CYP2C70 resulted in reduced TβMCA production, which subsequently increased serum IL-1β levels and exacerbated IR injury. Moreover, our findings suggested that TβMCA could inhibit canonical inflammasome activation in macrophages and attenuate inflammatory responses in a myeloid-specific S1PR2-GSDMD-dependent manner. Additionally, Gly-βMCA, a derivative of TβMCA, could effectively attenuate inflammatory injury in vivo and inhibit human macrophage pyroptosis in vitro. ConclusionsIR stress orchestrates hepatic BA metabolism to generate TβMCA, which attenuates hepatic inflammatory injury by inhibiting the myeloid S1PR2-GSDMD axis. Bile acids have immunomodulatory functions in liver reperfusion injury that may guide therapeutic strategies. Impact and implicationsOur research reveals that liver IR stress triggers reprogramming of BA metabolism. This functions as an adaptive mechanism to mitigate inflammatory injury by regulating the S1PR2-GSDMD axis, thereby controlling the release of IL-1β from macrophages. Our results highlight the crucial role of bile acids in regulating hepatocyte-immune cell crosstalk, which demonstrates an immunomodulatory function in liver reperfusion injury that may guide therapeutic strategies targeting bile acids and their receptors.

ER stress promotes mitochondrial calcium overload and activates the ROS/NLRP3 axis to mediate fatty liver ischemic injury.

Fatty livers are widely accepted as marginal donors for liver transplantation but are more susceptible to liver ischemia and reperfusion (IR) injury. Increased macrophage-related inflammation plays an important role in the aggravation of fatty liver IR injury. Here, we investigate the precise mechanism by which endoplasmic reticulum (ER) stress activates macrophage NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) signaling by regulating mitochondrial calcium overload in fatty liver IR. Control- and high-fat diet-fed mice were subjected to a partial liver IR model. The ER stress, mitochondrial calcium levels, and NLRP3 signaling pathway in macrophages were analyzed. Liver steatosis exacerbated liver inflammation and IR injury and enhanced NLRP3 activation in macrophages. Myeloid NLRP3 deficiency attenuated intrahepatic inflammation and fatty liver injury following IR. Mechanistically, increased ER stress and mitochondrial calcium overload were observed in macrophages obtained from mouse fatty livers after IR. Suppression of ER stress by tauroursodeoxycholic acid effectively downregulated mitochondrial calcium accumulation and suppressed NLRP3 activation in macrophages, leading to decreased inflammatory IR injury in fatty livers. Moreover, Xestospongin-C-mediated inhibition of mitochondrial calcium influx decreased reactive oxygen species (ROS) expression in macrophages after IR. Scavenging of mitochondrial ROS by mito-TEMPO suppressed macrophage NLRP3 activation and IR injury in fatty livers, indicating that excessive mitochondrial ROS production was responsible for macrophage NLRP3 activation induced by mitochondrial calcium overload. Patients with fatty liver also exhibited upregulated activation of NLRP3 and the ER stress signaling pathway after IR. Our findings suggest that ER stress promotes mitochondrial calcium overload to activate ROS/NLRP3 signaling pathways within macrophages during IR-stimulated inflammatory responses associated with fatty livers.

Liberal use of veno-arterial extracorporeal membrane oxygenation in combined sequential heart-liver transplantation.

Combined heart-liver transplantation (CHLT) is a rarely though increasingly performed procedure with evolving indications. Despite CHLT being performed at only a handful of centers, the use of intraoperative mechanical circulatory support to optimize hemodynamics and facilitate dual-organ transplantation varies widely. At our center, we liberally utilize veno-arterial extracorporeal membrane oxygenation (V-A ECMO) when a veno-venous shunt is anticipated to be insufficient in mitigating the hemodynamic perturbations associated with liver reperfusion. In this series, we describe our experience with V-A ECMO in sequential (heart-first) CHLT and demonstrate highly favorable outcomes with this strategy.

Efficacy of Taxifolin in The Prevention of Renal Injury Due to Liver Ischemia and Reperfusion

Aim: During surgical procedures such as liver resection and transplantation, ischemia/reperfusion (I/R) injury and related complications may occur at a rate of approximately 10%. Our study, we planned to investigate histologically and biochemically the efficacy of Taxifolin in the prevention of renal tissue damage in liver ischemia reperfusion. Methods: A total of 28 Wistar Albino rats with an average age of 8-10 weeks and weights of 250-300 grams were used in our study. Group 1 (n=7): control group, Group 2 (n=7): Taxifolin group; Taxifolin was administered orally at a dose of 50 mg/kg for 3 weeks, Group 3 (n=7): Liver I/R group, 30 minutes ischemia and 120 minutes reperfusion was performed. Group 4 (n=7): Taxifolin+Liver I/R group. Results: Kidney tissues of the liver I/R group showed atrophy, degeneration of tubule epithelium and increased TNF-α expression. In addition, deterioration in renal function tests was also monitored in this group. In the Taxifolin+Liver I/R group, a significant difference was observed on both histologic and biochemical basis compared to the Liver I/R group and a positive effect was observed (p&amp;lt;0.05). Outcome: As a consequence of hepatic ischemia and reperfusion, impairment in the function and histological appearance of renal tissues was observed and Taxifolin was monitored to be effective in eliminating these adverse effects.

Bicarbonate ringer’s solution could improve the intraoperative acid-base equilibrium and reduce hepatocellular enzyme levels after deceased donor liver transplantation: a randomized controlled study

BackgroundBicarbonate Ringer’s (BR) solution is a direct liver and kidney metabolism-independent HCO3− buffering system. We hypothesized that BR solution would be more effective in improving acid-base equilibrium and more conducive to better liver function than Acetate Ringer’s (AR) solution in conventional orthotopic liver transplantation (OLT) patients.MethodsSixty-nine adult patients underwent OLT. Patients in the bicarbonate and acetate groups received BR solution or AR solution as infused crystalloids and graft washing solution, respectively. The primary outcome was the effect on pH and base excess (BE) levels. The secondary outcome measures were the incidence and volume of intraoperative 5% sodium bicarbonate infusion and laboratory indicates of liver and kidney function.ResultsThe pH and absolute BE values changed significantly during the anhepatic phase and immediately after transplanted liver reperfusion in the bicarbonate group compared with the acetate group (all P < 0.05). The incidence and volume of 5% sodium bicarbonate infusion were lower in the bicarbonate group than in the acetate group (all P < 0.05). The aspartate transaminase (AST) level at 7 postoperative days and the creatine level at 30 postoperative days were significantly higher in the acetate group than in the bicarbonate group (all P < 0.05).ConclusionCompared with AR solution, BR solution was associated with improved intraoperative acid-base balance and potentially protected early postoperative liver graft function and reduced late-postoperative renal injury.

ADAR1 regulates macrophage polarization and is protective against liver ischemia and reperfusion injury

Liver ischemia and reperfusion injury (LIRI) is a major risk for the poor prognosis of patients receiving liver transplantation. The molecular mechanism involved in LIRI is complex and related to various cellular components. We previously reported that adenosine deaminase acting on RNA 1 (ADAR1) alleviated the allogeneic skin graft rejection by regulating macrophage polarization. However, the regulatory effects of ADAR1 on liver macrophages after LIRI remain largely unknown. In this study, we mainly adopted a mouse model of LIRI and cellular experiments with hypoxia and reoxygenation (HR) treatment to explore the regulatory roles of ADAR1 on liver macrophages under LIRI conditions. We found that IRI caused decreased ADAR1 in liver tissues and remarkable changes of liver macrophage polarization and profiles. ADAR1 supplementation alleviated the pathological injury caused by IRI and accelerated the activation of M2 macrophages in the liver of IRI mice. Increased hypoxia duration reduced ADAR1 expression levels in murine RAW264.7 macrophages at the transcriptional level. Further overexpression of ADAR1 significantly increased the expressions of anti-inflammatory cytokines and promoted M2 polarization of macrophages under HR exposure. ADAR1 knockdown exhibited opposite effects on macrophage polarization. Hence, ADAR1 promotes the M2 polarization of liver macrophages that may further alleviate LIRI. The protective effects of ADAR1 against LIRI provide a novel insight into the prevention and treatment of LIRI.

Perioperative Characteristics and Outcomes of Fontan Versus Non-Fontan Patients Undergoing Combined Heart-Liver Transplantation: A Retrospective Cohort Study

Combined heart-liver transplantation (CHLT) is becoming increasingly frequent as a maturing population of patients with Fontan-palliated congenital heart disease develop advanced liver fibrosis or cirrhosis. The authors present their experience with CHLT for congenital and noncongenital indications, and identify characteristics associated with poor outcomes that may guide intervention in high-risk patients. This was a single-center retrospective cohort study. This study was conducted at Vanderbilt University Medical Center in Nashville, Tennessee. The study included 16 consecutive adult recipients of CHLT at the authors' institution between April 2017 and February 2022. Eleven patients underwent transplantation for Fontan indications, and 5 were transplanted for non-Fontan indications. Compared with non-Fontan patients, Fontan recipients had longer cardiopulmonary bypass duration (199 v 119 minutes, p =m0.002), operative times (786 v 599 minutes, p = 0.01), and larger blood product transfusions (15.4 v 6.3 L, p = 0.18). Six of 16 patients required extracorporeal membrane oxygenation (ECMO), of whom 4 were Fontan patients who subsequently died. Patients who required ECMO had lower 5-hour lactate clearance (0.0 v 3.5 mmol/L, p = 0.001), higher number of vasoactive infusions, lower pulmonary artery pulsatility indices (0.58 v 1.77, p = 0.03), and higher peak inspiratory pressures (28.0 v 18.5 mmHg, p = 0.01) after liver reperfusion. Combined heart-liver transplantation in patients with Fontan-associated end-organ disease is particularly challenging and associated with higher recipient morbidity compared with non-Fontan-related CHLT. Early hemodynamic intervention for signs of ventricular dysfunction may improve outcomes in this growing high-risk population.

Vascular Reconstruction with the Cuff Technique in Mouse Orthotopic Liver Transplantation.

Mouse orthotopic liver transplantation is an effective methodology for investigating the underlying mechanisms of liver ischemia and reperfusion injury. However, the technical challenges pose a barrier to utilizing this valuable experimental model and passing on these skills to the next generation. The most challenging aspect of this procedure is vascular reconstruction, including the portal vein (PV), infrahepatic inferior vena cava (IHIVC), and suprahepatic inferior vena cava. The use of plastic cuffs, rather than sutures, allows for smoother PV and IHIVC reconstruction. Vessels are reconstructed by attaching a cuff made from an intravenous catheter to the tip of the graft vessel and interposing the cuff into the recipient vessel. The two most crucial aspects are properly visualizing the inner lumen of the vessel and avoiding the use of excessive force. Our aim is to provide a technical overview of vascular reconstructions using the cuff technique in recipient surgery. These technical tips for the cuff technique are expected to help microsurgeons facilitate vascular reconstruction and advance their research.

Interleukin-6 Levels During Normothermic Machine Perfusion Impact Postreperfusion Hemodynamics of Liver Graft Recipients: A Prospective Single-center Observational Study.

Hemodynamic instability after liver graft reperfusion increases recipient morbidity after liver transplantation. The etiologies of hemodynamic disturbances appear to be multifactorial and are poorly understood. Normothermic machine perfusion (NMP) provides an opportunity to analyze graft quality prior to transplantation. In the present study, we aim to investigate the influence of interleukin-6 (IL-6) levels during NMP on postreperfusion hemodynamics of the recipient. Consecutive NMP-liver transplants at a single-center were prospectively analyzed. Perfusate samples were collected at the beginning, after 6 h, and at the end of perfusion and analyzed for IL-6 levels. Mean arterial pressure (MAP) and catecholamine consumption during surgery were recorded. IL-6 levels at the end of NMP were correlated to donor and perfusion characteristics as well as changes in MAP and catecholamine requirements during the anhepatic and reperfusion phase. IL-6 perfusate measurements were assessed in 77 livers undergoing NMP and transplantation. Donor age, sex, cold ischemic time, and NMP time did not correlate with IL-6 levels. Perfusates of donation after circulatory death grafts showed higher IL-6 levels at the end of NMP than donation after brain death grafts. However, IL-6 levels at the end of NMP correlated with catecholamine requirements and MAP in the reperfusion phase. Per log10 increase in IL-6 levels, an increase of 42% points in administered catecholamine dose was observed, despite MAP being decreased by 3.6% points compared to baseline values. IL-6 levels may be a predictor for recipient hemodynamic instability during liver reperfusion. Larger studies are needed to confirm this finding.

MULTIPLE MACHINE LEARNING METHODS AND COMPARATIVE TRANSCRIPTOMICS IDENTIFY PIVOTAL GENES FOR ISCHEMIA-REPERFUSION INJURY IN HUMAN DONOR TISSUE UNDERGOING ORTHOTOPIC LIVER TRANSPLANTATION.

Background: Hepatic ischemia-reperfusion injury (HIRI) is a major complication affecting patient prognosis during the period after orthotopic liver transplantation (OLT). Although an increasing number of scientists have investigated the molecular biology of ischemia-reperfusion injury (IRI) during OLT in animal and cellular models in recent years, studies using comprehensive and high-quality sequencing results from human specimens to screen for key molecules are still lacking. Aims: The objective of this study is to explore the molecular biological pathways and key molecules associated with HIRI during OLT through RNA sequencing and related bioinformatics analysis techniques. Methods: The study was done by performing mRNA sequencing on liver tissue samples obtained from 15 cases of in situ liver transplantation patients who experienced ischemia and reperfusion injury within 1 year at Guizhou Medical University, and combined with bioinformatics analysis and machine learning methods, we identified the genes and transcription factors that are closely associated with IRI during in situ liver transplantation surgery. Results: There were 877 differentially expressed genes (DEGs) identified in the included liver samples, of which 817 DEGs were upregulated and 60 were downregulated. Functional enrichment analysis revealed significant enrichment of immune-related terms, such as inflammation, defense responses, responses to cytokines, immune system processes, and cellular activation. In addition, core gene enrichment analysis after cytoHubba screening suggested that liver reperfusion injury might be associated with translation-related elements as a pathway together with protein translation processes. Machine learning with the weighted correlation network analysis screening method identified PTGS2, IRF1, and CDKN1A as key genes in the reperfusion injury process. Conclusions: This study demonstrated that the pathways and genomes whose expression is altered throughout the reperfusion process might be critical for the progression of HIRI during OLT.

Preservation Efficacy of a Quercetin and Sucrose Solution for Warm Ischemically Damaged Porcine Liver Grafts

The University of Wisconsin (UW) solution is the gold standard for preserving the liver, kidneys, and pancreas. For renal preservation, the addition of the flavonoid, quercetin (QE), to the preservation solution reduces damage to renal tubular cells, and the addition of sucrose (Suc) is also beneficial for preservation. The aim of this study was to investigate the protective effects of QE and Suc on porcine livers in terms of warm and cold injury and to evaluate whether their use improves ischemia-reperfusion (I/R) injury after simple cold storage (CS). We tested porcine livers procured after 30 minutes of warm ischemia followed by preservation for 6 hours under the following 2 conditions: group 1, preserved with the CS/UW solution (n=4); group 2, preserved with the CS/UW solution containing Que 33.1 μM and Suc 0.1 M (n=6). All livers were evaluated using an ex vivo isolated liver reperfusion model with saline-diluted autologous blood. Aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase levels in group 2 were significantly lower at 30 minutes of reperfusion than in group 1. Furthermore, histologic evaluation by hematoxylin and eosin staining showed significantly fewer morphologic changes in group 2 than in group 1, as indicated by the total Suzuki score. Group 2 also had significantly better scores for sinusoidal congestion and hepatocyte cytoplasmic vacuolization. Adding Que and Suc to the UW solution can effectively prevent cold injury in livers donated after circulatory death.

Beneficial Effects of Combined Use of Extracorporeal Membrane Oxygenation and Hypothermic Machine Perfusion in Porcine Donors after Cardiac Death for Liver Transplantation.

Grafts from donors after cardiac death (DCD) have greatly contributed to expanding the donor organ pool. This study aimed to determine the benefits of subnormothermic extracorporeal membrane oxygenation (ECMO) and hypothermic machine perfusion (HMP) in a porcine model of DCD liver. Female domestic crossbred Large Yorkshire and Landrace pigs weighing approximately 20 kg were used. The abdominal aorta and inferior vena cava were cannulated and connected to an ECMO circuit for in situ perfusion of the abdominal organs at 22 °C for 60 min, 45 min after cardiac death. The pigs were divided into the cold storage (CS) group (n = 3), where liver grafts were preserved at 4 °C, and the HMP group (n = 3), where liver grafts were preserved by HMP at 8-10 °C. After 4 h of preservation, liver function was evaluated using an isolated liver reperfusion model for 2 h. Although the difference was insignificant, the liver effluent enzyme levels in the HMP group were lower than those in the CS group. Furthermore, morphological findings showed fewer injured hepatocytes in the HMP group than in the CS group. The combined use of in situ subnormothermic ECMO and HMP was beneficial for the functional improvement of DCD liver grafts.

Machine perfusion preservation with hemoglobin based oxygen vesicles alleviate ultrastructural damages in porcine liver donated after cardiac death.

Midthermic machine perfusion (MMP) of post-circulatory arrest donor liver grafts has the advantage of preserving the functional ultrastructure of hepatocytes in donor grafts. It was reported that oxygenation during MMP reduces portal venous resistance and increases bile production. The MMP with hemoglobin-based oxygen vesicles (HbV) keeps the lower aspartate aminotransferase level (an indicator of liver injury) and maintains the functional ultrastructure of mitochondria in the hepatocytes. To evaluated differences of ultrastructural damages in donor livers between the MMP with and without HbV, porcine liver grafts after 60 min of warm ischemia were perfused at 22°C for 4 h with or without HbV, and a part of liver grafts were analyzed by transmission electron microscopy (TEM) and osmium-maceration scanning electron microscopy (OM-SEM). The remaining grafts were perfused with autologous blood at 38°C for 2 h in an isolated liver reperfusion model (IRM) that mimics the inside of the body after transplantation, and then analyzed by TEM and OM-SEM. Hepatocytes after MMP had small round mitochondria with rod-shaped cristae and reticulovesicular rough endoplasmic reticulum (rER) in both HbV(+) and HbV(-) livers. After IRM of HbV(+) livers, the well-developed lamellar rER was often found in hepatocytes. Liver sinusoidal endothelial cells (LSECs) after MMP contained some large vacuolar structures containing amorphous garbage in the cytoplasm, and their size along with appearance frequency were smaller and lower, respectively, in HbV(+) livers than HbV(-). Oxygenation during the MMP by using HbV suppressed the ultrastructural damages in donor livers, in particular for the LSECs. RESEARCH HIGHLIGHTS: Liver sinusoidal endothelial cells after midthermic machine perfusion had large vacuolar organelles with amorphous garbage. Oxygenation during the perfusion made them less and smaller, ultrastructurally supporting its utility.

KARACİĞER İSKEMİ VE REPERFÜZYON HASARINDA KALP DOKUSUNDA MEYDANA GELEN HASARIN ÖNLENMESİNDE TAKSİFOLİN’İN KORUYUCU ETKİNLİĞİ: DENEYSEL ÇALIŞMA

Aim: Liver ischemia and reperfusion (I/R) is a serious, irreversible health problem in clinical practice. Taxifolin (Tax) is an easy to obtain and use agent found in maritime pine bark, Douglas fir bark and Siberian larch wood. In this study, we examined the protective efficacy of Taxifolin in the correction of cardiac tissue damage that may develop in liver I/R damage. Methods: In our study, a total of 28 Wistar Albino rats, 8-10 weeks old, weighing 250-300 grams, were used. Group 1 (n=7): control group, Group 2 (n=7): Tax group with 50 mg/kg dose orally for 3 weeks, Group 3 (n=7): Liver I/R group for 30 minutes ischemia and 120 minutes of reperfusion were performed. Group 4 (n=7): Tax+Liver I/R group. Results: In our study, MDA analysis was performed to evaluate oxidative stress. In the statistical analysis of MDA values, we observed that there was a statistically significant difference between the serum MDA values of the Tax group and the Tax+Liver I/R group, and the MDA level of the Tax group was lower (p&amp;lt;0.05). In myocyte damage scoring, we observed that the liver I/R group had the highest damage score, while the damage score of the Tax+Liver I/R group was significantly lower than the I/R group (p&amp;lt;0.05). Conclusion: As a result of our study, we observed that there was an increase in serum MDA levels as a result of liver I/R and histopathological changes occurred in the heart tissue. However, Taxifolin has been successful in ameliorating this situation.