Ischemia-reperfusion injury and its relationship with early allograft dysfunction in liver transplant patients

Haemoadsorption cartridge connected to the machine perfusion for donation after circulatory death porcine liver marginal grafts

BACKGROUND

Marginal donation after circulatory death (DCD) liver grafts are carefully used to combat the constant shortage of donors. Clinically, the worst outcomes are mainly related to severe ischemia-reperfusion-injury and the dangerous effect of various inflammatory cytokines (CK). The machine perfusion (MP) is a promising device to rescue these grafts.

AIM

To analyze the role of MP connected to a sorbent cartridge (PerSorb^®) and used for very damaged DCD pig livers.

METHODS

Seven grafts were procured from pigs from a slaughterhouse. Grafts were made very marginal with at least 60 minutes of donor warm ischemia time and 24 hours of static-cold ischemia time: (1) 3 grafts were perfused in hypothermic MP with PerSorb (Sorb); (2) 2 other grafts in hypothermic MP (HMP) without the cartridge (NoSorb); and (3) The other 2 livers stored in the ice box (NoTreat). The CK were measured at HMP start (T0) and at the end (Tend). Biopsies were taken at T0 and Tend.

RESULTS

All 5 grafts treated with HMP had a negative lactate trend after 3 hours of treatment (8.83 at T0 vs 6.4 at Tend of Sorb; 15 at T0 vs 5.45 at Tend for NoSorb, P value > 0.05). At Tend, both Sorb and NoSorb groups had better hemodynamic parameters, comparable between the two groups. Enzyme-linked immunosorbent assay analysis showed a reduction of monocyte chemotactic protein-1, tumor necrosis factor-alpha and interleukin-1β for NoSorb group at Tend and a complete downregulation to physiological levels of the same CK in Sorb livers after 3 hours of treatment. Biopsies showed a reduction of the perisinusoidal edema for the Sorb grafts compared with the NoSorb livers.

CONCLUSION

These data suggest a potential protective role of treatment of grafts with MP and sorbent cartridge in reducing the inflammatory response after a severe ischemic injury.

Outcomes of donation after circulatory death (DCD) and ex-vivo lung perfusion (EVLP) lung transplantation

BACKGROUND

Donation after circulatory death (DCD) and ex-vivo lung perfusion (EVLP) have been adopted to expand the donor pool in lung transplantation, but outcomes data have been conflicting. This study explores outcomes of DCD and EVLP lung transplantation in the modern era.

METHODS

The United Network for Organ Sharing database was queried for adult lung transplants from January 1, 2015 to March 1, 2023. Loss to follow-up, multiorgan, and prior lung transplants were excluded. DCD versus donation after brain death (DBD) lung transplants were compared with subgroup analysis +/- EVLP. Outcomes were survival and postoperative complications.

RESULTS

The study included 1,103 DCD (221 with EVLP and 882 without) and 17,973 DBD lung transplants (524 with EVLP and 17,449 without). Median follow-up was 3 years. DCD donors were less likely to be CDC high risk (19.3% vs 24.1%, p < 0.001), have purulence on bronchoscopy (13.3% vs 18.3%, p < 0.001), or infiltrates on chest X-ray (66.7% vs 67.8%, p = 0.013). EVLP was more likely to be used for DCD transplants (20.0% vs 2.9%, p < 0.001). After transplant, DCD recipients were more likely to be reintubated (24.3% vs 18.5%, p < 0.001) and require ECMO within 72 hours (14.9% vs 7.8%, p < 0.001), and DCD donation was an independent risk factor for these complications on multivariable logistic regression. Overall survival did not differ significantly between DCD and DBD transplants on adjusted survival analysis in the early or modern era (p = 0.774 and p = 0.468, respectively). On subgroup analysis, the DCD+EVLP cohort had significantly worse survival in the modern era, which remained significant after adjusting for donor and recipient factors (p = 0.005). EVLP was an independent risk factor for graft failure in the DCD cohort (hazard ratio [HR] 1.33, 95% confidence interval [CI] 1.00-1.77, p = 0.047) but did not significantly affect DBD graft survival (p = 0.870). Risk factors for graft failure and mortality in the DCD+EVLP cohort included pulmonary hypertension (HR 77.5, 95% CI 6.15-979, p < 0.001), transfusion before transplant (HR 2.60, 95% CI 1.07-6.31, p = 0.035), elevated creatinine (HR 2.82, 95% CI 1.34-5.90, p = 0.006), and higher allocation score (HR 1.02, 95% CI 1.00-1.04, p = 0.017) CONCLUSIONS: Study findings suggest increased risks of mortality and perioperative complications following transplantation with DCD lungs that have undergone EVLP. DCD lung transplantation without EVLP confers equivalent survival but with some increase in perioperative complications. Further investigation and careful recipient selection are warranted to optimize the use of these extended criteria donors in the modern era.

Impact of aortic calcification at the origin of celiac artery on post-operative outcomes of major hepatectomy: A significant risk factor for posthepatectomy liver failure

PURPOSE

Aortic calcification is associated with arteriosclerosis and is often seen in patients undergoing hepatectomy. However, its impact on post-operative outcomes after major hepatectomy is still unclear.

METHODS

From July, 2015 to December, 2022, 127 patients who underwent resection of three or more adjacent liver segments (major hepatectomy) were retrospectively reviewed. Aortic calcification at the origin of celiac artery was assessed on pre-operative abdominal CT scan images. pPerioperative factors and postoperative outcomes were compared between patients with and without aortic calcification. Uni-variable and multi-variable analyses were performed to identify risk factors of posthepatectomy liver failure (PHLF).

RESULTS

Aortic calcification at the origin of celiac artery was observed in 62 (48.8%) of 127 patients. Those with aortic calcification were significantly older and had a higher incidence of hypertension, as a comorbidity, compared to those without. Furthermore, incidences of both post-operative liver failure and other complications were significantly higher among patients with aortic calcification, who also had a longer hospital stay. Multivariable logistic analysis identified aortic calcification and longer operation time as independent risk factors of PHLF. Additionally, stenosis of the celiac artery also impacted the development of PHLF.

CONCLUSION

These findings indicate that aortic calcification at the origin of celiac artery is associated with advanced age and may be a risk factor of PHLF following major hepatectomy.

Insulin-induced gene 2 alleviates ischemia-reperfusion injury in steatotic liver by inhibiting GPX4-dependent ferroptosis

Hepatic steatosis significantly elevates the vulnerability of the graft to ischemia-reperfusion (I/R) injury during liver transplantation (LT). We investigated the protective role of insulin-induced gene 2 (Insig2) in steatotic liver's I/R injury and underlying mechanisms. Employing mouse model with Insig2 knock-out or hepatocyte-specific overexpression and high-fat diets to induce steatosis, we subjected these mice to hepatic I/R injury. The primary hepatocytes isolated from steatotic liver were used in in vitro hypoxia/reoxygenation (H/R) experiment. Our integrated in vivo and in vitro approach uncovered that Insig2 deficiency exacerbated steatotic liver's damage following hepatic I/R injury, whereas its overexpression offers protection. Mechanically, integrative analysis of transcriptome, proteome, and metabolome found that Insig2 deficiency disturbed lipid metabolism and oxidative stress homeostasis, particularly inhibiting GPX4 expression to induce ferroptosis. Furthermore, chemical inhibition of ferroptosis reversed the deleterious effect of Insig2 deficiency; whereas the protective influence of Insig2 overexpression was negated by the target inhibition of GPX4, leading to an exacerbation of hepatic I/R damage. These insights underscored the potential of the Insig2-GPX4 axis as a therapeutic target, presenting a novel avenue for enhancing the resilience of steatotic liver grafts against I/R injury.

Diagnostic value and immune infiltration characterization of WTAP as a critical m6A regulator in liver transplantation

BACKGROUND

RNA N6-methyladenosine (m6A) regulators are essential for numerous biological processes and are implicated in various diseases. However, the comprehensive role of m6A regulators in the context of liver transplantation (LT) remains poorly understood. This study aimed to illustrate the relationship between m6A regulators and ischemia-reperfusion injury (IRI) following LT.

METHODS

Datasets were acquired from the Gene Expression Omnibus database. Differential analysis of the merged data identified the differentially expressed m6A regulators. Random forest (RF) models and nomograms were used to forecast the incidence and assess the IRI risk following LT. m6A regulators were classified into distinct subgroups using cluster analysis. The differential gene expression was validated using immunohistochemistry, immunofluorescence, and Western blotting.

RESULTS

We found significant disparities in the gene expression levels of the three m6A regulators between patients with and without LT. Wilms' tumor 1-associating protein (WTAP) expression was upregulated following LT. The RF models exhibited a high degree of accuracy in predicting IRI risk. Immune infiltration analysis showed that WTAP was an immune-associated m6A regulator that was closely associated with T and B cells. WTAP expression in the rat LT model was upregulated after 24 h of reperfusion, which was consistent with the results of the bioinformatics analysis.

CONCLUSIONS

WTAP has a high diagnostic value for IRI in LT and influences the immune status of patients. Hence, WTAP, as a significant regulator of m6A, is a potential biomarker for the detection and implementation of immunotherapy for IRI following LT.

Definition, Prognosis, and Complication Analysis of Early Allograft Dysfunction in Pediatric Liver Transplantation: A Retrospective Cohort Study

BACKGROUND

The definition of early allograft dysfunction (EAD) varies, and has hardly been studied in pediatric transplantation (pLT) since the adult EAD definition is not easily applicable to pLT.

METHODS

A retrospective analysis was conducted on consecutive pLT patients aged <18 at the Department of Pediatric Transplantation of Tianjin First Central Hospital from April 2013 to December 2022. The definition of EAD explored in this study is (1) international normalized ratio ≥2.8 on day 1 and aspartate aminotransferase >1500 IU/mL within the first 7 days or (2) total bilirubin ≥5 mg/dL on day 7. The overall survival of patients and graft survival at 90 days after surgery were compared between this new definition and the adult EAD definition.

RESULTS

A total of 1620 pLT recipients were included in the study, of which 179 (11.0 %) recipients met the new definition of EAD for pLT. Twenty-five (13.97 %) died and 37 (20.67 %) graft lost within 90 days. The RR_death under Olthoff's EAD definition and our EAD definition are 3.45 and 9.57, respectively; The RR_graft_loss under Olthoff's EAD definition and our EAD definition are 4.18 and 11.48, respectively. A total of 97 (18.98 %) of 511 recipients who received deceased donor liver transplantation (DDLT) met the new definition of EAD, 18 (18.56 %) died and 29 (29.90 %) graft lost within 90 days. In DDLT group, the RR_death under Olthoff's EAD definition and our EAD definition are 2.29 and 10.98, respectively; The RR_graft_loss under Olthoff's EAD definition and our EAD definition are 2.34 and 11.24, respectively.

CONCLUSION

The broadly used Olthoff's EAD definition in adult liver transplantation is unsuitable for pLT use. The EAD definition established in this study is more suitable for patients <18 years old who received pLT, especially those <18 years old who received DDLT.

Recipient toll-like receptor 4 determines the outcome of ischemia-reperfusion injury in steatotic liver transplantation in mice

Toll-like receptor 4 (TLR4) plays a crucial role in ischemia-reperfusion injury (IRI) after liver transplantation (LT). However, the role of TLR4 in the context of steatotic grafts remains unclear. In this study, we developed a mouse model to explore IRI mechanisms in steatotic LT using TLR4 knockout mice as recipients. We successfully transplanted steatotic grafts with approximately 35% macrosteatosis and 5 hours of cold storage. Compared to normal LT, steatotic LT resulted in significantly higher serum level of alanine aminotransferase and high mobility group box 1 (HMGB1), higher transcriptional expression of inflammatory markers (C-X-C motif chemokine ligand 2, caspase-1, and caspase-11), and increased infiltration of CD11b-positive cells, correlating with lower survival. Serum HMGB1 and cleaved caspase-3 activation peaked earlier than serum alanine aminotransferase, with cold-stored steatotic grafts releasing more HMGB1. Notably, TLR4 knockout recipients demonstrated improved survival, attenuated inflammatory response, and reduced apoptosis. These findings suggest that TLR4 deficiency in recipients ameliorates IRI in steatotic LT, highlighting the importance of recipient immune modulation in mitigating steatotic graft injury.

Latin American association for the study of the liver (ALEH) guidance on postoperative care after liver transplantation

Liver transplantation (LT) is a well-established therapy for patients with decompensated cirrhosis and early-stage hepatocellular carcinoma. Liver transplantation activity varies sharply across Latin American (LATAM) countries due to differences in resources, expertise, and funding and local attitudes toward organ donation and transplantation. This current guidance of postoperative care after LT is the first position paper of the Latin American Association for the Study of the Liver (ALEH) Special Interest Group (SIG), drawing evidence-based recommendations regarding immediate and long-term postoperative care of LT recipients, taking into consideration their applicability in Latin America.

Ischemia-Reperfusion Injury at Time-Zero Biopsy as a Prognostic Factor in Predicting Liver Graft Outcome in Egyptian Living Donor Liver Transplanted Patients

Background and Aims: Ischemia-reperfusion injury (IRI) is believed to contribute to the early dysfunction of the graft as well as the survival of the patients following liver transplantation (LT). This study is aimed at ascertaining the role of time-zero biopsies in predicting early graft dysfunction and 5-year patient survival after living donor liver transplantation (LDLT). Patients and Methods: From February 2012 to August 2017, time-zero biopsies were obtained from 60 patients. Histological grading of time-zero biopsies was performed to identify the severity of IRI. Patients were divided into two groups: no or minimal to mild IRI versus moderate to severe IRI. Results: Time-zero biopsies of 60 liver allografts revealed no or minimal to mild IRI (n = 38, 63.3%) (Group 1) versus moderate to severe IRI (n = 22, 36.7%) (Group 2). Group 2 recipients indicated a significant increase in serum bilirubin and a higher incidence of early graft dysfunction. There were significant survival differences between the two groups (p = 0.033), and the rate of death was higher in the moderate to severe IRI group. Recipient age, steatosis, and longer CIT were identified as independent predictors of moderate to severe IRI. Conclusion: Time-zero biopsies with moderate to severe IRI upon biopsy can predict adverse clinical outcomes following LT.

Early Allograft Dysfunction after liver transplantation- definition, incidence and relevance in a single-centre analysis

PURPOSE

Early Allograft Dysfunction (EAD) is a serious complication following liver transplantation. With more marginal donors and critical recipients, identifying EAD risk factors and their impact on long-term outcomes is crucial.

METHODS

We reviewed all liver transplants performed between 2007 and 2017 at our institution, excluding pediatric recipients, combined thoracic transplants, and retransplants in the same hospital stay. EAD was defined as either: (i) AST/ALT > 2000 IU/l in first 7 postoperative days (POD), (ii) Bilirubin ≥ 10 mg/dl on POD 7, (iii) INR ≥ 1.6 on POD 7.

RESULTS

Of the 621 cases analyzed, the EAD rate was 53.6%. Multivariate analysis identified only donor-dependent variables as independent risk factors for the onset of EAD: donor age (p = 0.012), donor serum sodium (p = 0.021), cold ischemic time (p = 0.007) and graft weight (p < 0.001). EAD significantly impaired graft survival (69.2% vs. 86.2% after 1 year; p = 0.005) but did not impact long-term patient survival (76.3% vs. 87.6% after 1 year; p = 0.162). Of the EAD components, elevated INR proved to be the only reliable predictor of patient mortality. Additionally, an AST/ALT concentration of > 4000 IU/l significantly improved the predictive value of the EAD definition for patient survival (p = 0.002).

CONCLUSIONS

EAD risk factors are primarily donor-based and significantly impair graft but not patient survival. The high EAD rates and increased use of marginal grafts suggest the need to adjust conventional EAD definitions to optimize graft allocation in the future.

Suppression of Hepatocyte Ferroptosis via USP19-Mediated Deubiquitination of SLC7A11 in Ischemia-Free Liver Transplantation

Ischemia-free liver transplantation (IFLT) is developed as a novel clinical approach to avoid ischemia-reperfusion injury (IRI). This study aims to identify the most distinguished programmed cell death pathway in grafts undergoing IFLT versus conventional liver transplantation (CLT) and to explore the underlying mechanism. Ferroptosis is the most distinct programmed cell death form between IFLT and CLT grafts. Among various cell death inhibitors, the ferroptosis inhibitor (Ferrostain-1) is the most effective one to prevent hepatocytes from damage induced by oxygen deprivation/reoxygenation (OGD/R). Hepatocyte ferroptosis is significantly alleviated in IFLT versus CLT grafts in both human beings and pigs. Ubiquitination enzyme screening identifies augmented amounts of ubiquitin-specific protease 19 (USP19) in IFLT versus CLT grafts. The upregulation of USP19 in the grafts is correlated with reduced pathological Suzuki's score, lower post-transplant peak liver enzyme level, and less early allograft dysfunction in liver transplant recipients. USP19 overexpression mitigates post-transplant liver injury in mice. Mechanistically, USP19 inhibits the degradation of solute carrier family 7 member 11 (SLC7A11) by removing its K63-linked ubiquitin chains. Notably, USP19 overexpression reduces ferroptosis and IRI in a SLC7A11-dependent manner in mice. Collectively, USP19-mediated suppression of hepatocyte ferroptosis via deubiquitinating SLC7A11 is a key mechanism by which IFLT abrogates graft IRI.

Validation of a Pretransplant Risk Prediction Model for Early Allograft Dysfunction After Living-donor Liver Transplantation

BACKGROUND

Early allograft dysfunction (EAD) affects outcomes in liver transplantation (LT). Existing risk models developed for deceased-donor LT depend on posttransplant factors and fall short in living-donor LT (LDLT), where pretransplant evaluations are crucial for preventing EAD and justifying the donor's risks.

METHODS

This retrospective study analyzed data from 2944 adult patients who underwent LDLT at 17 centers between 2016 and 2020. We developed a logistic regression model to predict EAD based on this development cohort. We used data from 1020 patients at the King Faisal Transplant Center for external validation.

RESULTS

In the development cohort, 321 patients (10.9%) experienced EAD. These patients had poorer health status, more liver decompensation, and higher requirements of hospitalization than those without EAD. Multivariable logistic regression identified independent pretransplant predictors of EAD: laboratory Model for End-Stage Liver Disease score (odds ratio [OR], 1.08; 95% confidence interval [CI], 1.06-1.09), the necessity for hospitalization at the time of transplant (OR, 2.58; 95% CI, 2.00-3.30), and graft weight in kilogram (OR, 0.27; 95% CI, 0.17-0.45). Using these predictors, we developed the model for EAD after LDLT, which demonstrated strong discriminative ability in the development cohort with an area under the curve (AUC) of 0.71 (95% CI, 0.68-0.74). The model maintained high discrimination during internal validation (AUC, 0.70; 95% CI, 0.67-0.73) and showed a modest reduction in discriminative power in external validation (AUC, 0.65; 95% CI, 0.61-0.68).

CONCLUSIONS

EAD post-LDLT is influenced by the recipient's pretransplant health condition and the graft weight. Integrating the model for EAD after LDLT into the pretransplant process of pairing donors and recipients can enhance the safety and efficacy of LDLT.

Exercise Preconditioning of the Donor Liver Decreases Cold Ischemia/Reperfusion Injury in a Mouse Model

BACKGROUND

Liver transplantation stands as the primary treatment for end-stage liver disease, with demand surging in recent decades because of expanded indications. However, hepatic ischemia/reperfusion injury can lead to liver transplant failure in both deceased donor and living donor transplantation. This study explored whether preconditioning donor livers through exercise training (ExT) could mitigate cold ischemic injury posttransplantation.

METHODS

Donor C57BL/6 mice underwent ExT via treadmill running or remained sedentary. After 4 wk, the donor liver underwent cold storage and subsequent orthotopic liver transplantation or ex vivo warm reperfusion.

RESULTS

Donor liver from mice subjected to ExT showed significantly decreased hepatic injury on reperfusion. Tissue histology revealed decreased sinusoidal congestion, vacuolization, and hepatocellular necrosis in livers from ExT mice, and immunofluorescence staining further revealed a decreased number of apoptotic cells in ExT grafts. Livers from ExT donors expressed decreased intragraft inflammatory cytokines cascade, decreased neutrophil infiltration and neutrophil extracellular traps, and increased M2 phenotype of recipient macrophages compared with grafts from sedentary mice. After cold storage, liver grafts from ExT donors showed decreased accumulation of reactive oxygen species and decreased levels of cytochrome c and high mobility group box 1 released in the liver effluent. In addition, ExT grafts showed upregulated peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and higher levels of mitochondrial content. Similar effects of decreased hepatic injury were observed in wild-type mice when pretreated with a PGC-1α stimulator ZLN005 instead of ExT.

CONCLUSIONS

These findings suggest that augmenting hepatocytic mitochondrial content through donor exercise or PGC-1α stimulation may offer therapeutic avenues to mitigate postreperfusion inflammation and improve transplant outcomes.

Comprehensive analysis of cuproptosis-related genes involved in immune infiltration and their use in the diagnosis of hepatic ischemia-reperfusion injury: an experimental study

BACKGROUND

Hepatic ischemia-reperfusion injury (HIRI) is a common injury not only during liver transplantation but also during major hepatic surgery. HIRI causes severe complications and affects the prognosis and survival of patients. Cuproptosis, a newly identified form of cell death, plays an important role in a variety of illnesses. However, its role in HIRI remains unknown.

MATERIALS AND METHODS

The GSE151648 dataset was mined from the Gene Expression Omnibus (GEO) database, and differences were analyzed for intersections. Based on the differentially expressed genes (DEGs), functional annotation, differentially expressed cuproptosis-related genes (DE-CRGs) identification and lasso logistic regression were conducted. Correlation analysis of DE-CRGs and immune infiltration was further conducted, and DE-CRGs were applied to construct an HIRI diagnostic model. The hierarchical clustering method was used to classify the specimens of HIRI, and functional annotation was conducted to verify the accuracy of these DE-CRGs in predicting HIRI progression. The GSE14951 microarray dataset and GSE171539 single-cell sequencing dataset were chosen as validation datasets. At the same time, the significance of DE-CRGs was verified using a mouse model of HIRI with cuproptosis inhibitors and inducers. Finally, a network of transcription-factor-DE-CRGs and miRNA-DE-CRGs was constructed to reveal the regulation mechanisms. And potential drugs for DE-CRGs were predicted using Drug-Gene Interaction Database (DGIdb).

RESULTS

Overall, 2390 DEGs and 19 DE-CRGs were identified. Through machine learning algorithms, 8 featured DE-CRGs (GNL3, ALAS1, TSC22D2, KLF5, GTF2B, DNTTIP2, SLFN11 and HNRNPU) were screened, and 2 cuproptosis-related subclusters were defined. Based on the 8 DE-CRGs obtained from the HIRI model [area under the curve (AUC)=0.97], the nomogram model demonstrated accuracy in predicting HIRI. Eight DE-CRGs were highly expressed in HIRI samples and were negatively related to immune cell infiltration. A higher level of immune infiltration and expression of CRG group B was found in the HIRI population. Differences in cell death and immune regulation were found between the 2 groups. The diagnostic value of the 8 DE-CRGs was confirmed in the validation of two datasets. The identification of 7 DE-CRGs (SLFN11 excluded) by HIRI animal model experiments was also confirmed. Using hTFtarget, miRWalk and DGIDB database, we predicted that 17 transcription factors, 192 miRNAs and 10 drugs might interact with the DE-CRGs.

CONCLUSION

This study shows that cuproptosis may occur in HIRI and is correlated with immune infiltration. Additionally, a cuproptosis-related predictive model was constructed for studying the causes of HIRI and developing targeted treatment options for HIRI.

Group 1 innate lymphoid cells protect liver transplants from ischemia-reperfusion injury via an interferon gamma-mediated pathway

As important immune regulatory cells, whether innate lymphoid cells (ILCs) are involved in liver transplantation (LT) remains unclear. In a murine orthotopic LT model, we dissected roles of ILCs in liver ischemia-reperfusion injury (IRI). Wild-type (WT) grafts suffered significantly higher IRI in Rag2-γc double knockout (DKO) than Rag2 knockout (KO) recipients, in association with downregulation of group 1 ILCs genes, including interferon gamma. Antibody-mediated ILC depletion or interferon gamma neutralization in Rag2 KO recipients increased, while interferon gamma treatment in DKO recipients reduced, liver graft injuries. At the donor side, grafts from DKO mice or anti-NK1.1-treated WT mice suffered significantly higher IRI, while grafts treated with interferon gamma during cold preservation decreased IRI. Thus, both recipient and donor group 1 ILCs protect liver grafts from IRI. Low-dose interferon gamma upregulated c-FLIP expression in vitro and in vivo and protected hepatocytes from inflammatory cell death. In human liver graft biopsies, single-cell RNA-sequencing analysis revealed group 1 ILCs produce interferon gamma. The c-FLIP levels were positively correlated with interferon gamma in pretransplant biopsies. Grafts with higher c-FLIP were associated with lower caspase-8 activation, IRI gradings, and frequency of early allograft dysfunction post-LT. Our study reveals a novel interferon gamma-mediated cytoprotective role of group 1 ILCs in LT.

Intraoperative Hyperspectral Imaging Predicts Early Allograft Dysfunction and Overall Survival in Liver Transplantation

Objective

This study explored the novel application of hyperspectral imaging (HSI) for in vivo allograft perfusion assessment during liver transplantation (LT) and its potential value for predicting early allograft dysfunction (EAD), graft, and overall survival (OS).

Background

LT is a well-established therapy for acute and chronic liver diseases, with excellent outcomes. However, a significant proportion of recipients experience EAD, which affects graft and OS. EAD is associated with ischemia-reperfusion injury. HSI is a noninvasive imaging modality that provides information on tissue characteristics, such as tissue hemoglobin, water index, oxygenation, and perfusion.

Methods

We included all patients who underwent orthotopic LT with full-size allografts between 2019 and 2021. HSI was performed 15 minutes after reperfusion of the donor liver and subsequently analyzed. Furthermore, we collected data on postoperative graft function and clinical outcomes.

Results

A total of 73 LT recipients were included in this study. Around 56.9% had expanded criteria donors (N = 41). The mean model for end-stage liver disease score was 22 (±10). Eighteen patients (25%) had EAD. The statistical analysis demonstrated that recipients with EAD had significantly lower near-infrared (NIR) perfusion values after reperfusion. Recipients with low NIR had more pronounced reperfusion injury in postoperative laboratory studies. OS was significantly lower in recipients with low NIR than in those with high NIR (P = 0.049).

Conclusions

HSI is a promising, noninvasive tool, offering real-time, detailed graft perfusion assessment during LT. The fusion of spatial and spectral information is unique to HSI, making it an essential imaging technology for the further development of AI applications in surgery.

Intraoperative Anesthetic Strategies to Mitigate Early Allograft Dysfunction After Orthotopic Liver Transplantation: A Narrative Review

Orthotopic liver transplantation (OLT) is the most effective treatment for patients with end-stage liver disease (ESLD). Hepatic insufficiency within a week of OLT, termed early allograft dysfunction (EAD), occurs in 20% to 25% of deceased donor OLT recipients and is associated with morbidity and mortality. Primary nonfunction (PNF), the most severe form of EAD, leads to death or retransplantation within 7 days. The etiology of EAD is multifactorial, including donor, recipient, and surgery-related factors, and largely driven by ischemia-reperfusion injury (IRI). IRI is an immunologic phenomenon characterized by dysregulation of cellular oxygen homeostasis and innate immune defenses in the allograft after temporary cessation (ischemia) and later restoration (reperfusion) of oxygen-rich blood flow. The rising global demand for OLT may lead to the use of marginal allografts, which are more susceptible to IRI, and thus lead to an increased incidence of EAD. It is thus imperative the anesthesiologist is knowledgeable about EAD, namely its pathophysiology and intraoperative strategies to mitigate its impact. Intraoperative strategies can be classified by 3 phases, specifically donor allograft procurement, storage, and recipient reperfusion. During procurement, the anesthesiologist can use pharmacologic preconditioning with volatile anesthetics, consider preharvest hyperoxemia, and attenuate the use of norepinephrine as able. The anesthesiologist can advocate for normothermic regional perfusion (NRP) and machine perfusion during allograft storage at their institution. During recipient reperfusion, the anesthesiologist can optimize oxygen exposure, consider adjunct anesthetics with antioxidant-like properties, and administer supplemental magnesium. Unfortunately, there is either mixed, little, or no data to support the routine use of many free radical scavengers. Given the sparse, limited, or at times conflicting evidence supporting some of these strategies, there are ample opportunities for more research to find intraoperative anesthetic strategies to mitigate the impact of EAD and improve postoperative outcomes in OLT recipients.

Short-term postoperative bacteriobilia or fungibilia in liver transplantation patients with donation after circulatory death allografts associated with a longer hospital stay: A single-center retrospective observational study in China

BACKGROUND

Normal bile is sterile. Studies have shown that cholangitis after liver transplantation (LT) was associated with a relatively poor prognosis. It remains unclear whether the bacteriobilia or fungibilia impact the patient outcomes in LT recipients, especially with donation after circulatory death (DCD) allografts, which was correlated with a higher risk of allograft failure.

METHODS

This retrospective study included 139 LT recipients of DCD grafts from 2019 to 2021. All patients were divided into two groups according to the presence or absence of bacteriobilia or fungibilia. The prevalence and microbial spectrum of postoperative bacteriobilia or fungibilia and its possible association with outcomes, especially hospital stay were analyzed.

RESULTS

Totally 135 and 171 organisms were isolated at weeks 1 and 2, respectively. Among all patients included in this analysis, 83 (59.7%) developed bacteriobilia or fungibilia within 2 weeks post-transplantation. The occurrence of bacteriobilia or fungibilia [β = 7.43, 95% CI (confidence interval): 0.02 to 14.82, P = 0.049], particularly the detection of Pseudomonas (β = 18.84, 95% CI: 6.51 to 31.07, P = 0.003) within 2 weeks post-transplantation was associated with a longer hospital stay. However, it did not affect the graft and patient survival.

CONCLUSIONS

The occurrence of bacteriobilia or fungibilia, particularly Pseudomonas within 2 weeks post-transplantation, could influence the recovery of liver function and was associated with prolonged hospital stay but not the graft and patient survival.

Mechanistic Insights into Alternative Gene Splicing in Oxidative Stress and Tissue Injury

Significance: Oxidative stress (OS) and inflammation are inducers of tissue injury. Alternative splicing (AS) is an essential regulatory step for diversifying the eukaryotic proteome. Human diseases link AS to OS; however, the underlying mechanisms must be better understood. Recent Advances: Genome‑wide profiling studies identify new differentially expressed genes induced by OS-dependent ischemia/reperfusion injury. Overexpression of RNA-binding protein RBFOX1 protects against inflammation. Hypoxia-inducible factor-1α directs polypyrimidine tract binding protein 1 to regulate mouse carcinoembryonic antigen-related cell adhesion molecule 1 (Ceacam1) AS under OS conditions. Heterogeneous nuclear ribonucleoprotein L variant 1 contains an RGG/RG motif that coordinates with transcription factors to influence human CEACAM1 AS. Hypoxia intervention involving short interfering RNAs directed to long-noncoding RNA 260 polarizes M2 macrophages toward an anti-inflammatory phenotype and alleviates OS by inhibiting IL-28RA gene AS. Critical Issues: Protective mechanisms that eliminate reactive oxygen species (ROS) are important for resolving imbalances that lead to chronic inflammation. Defects in AS can cause ROS generation, cell death regulation, and the activation of innate and adaptive immune factors. We propose that AS pathways link redox regulation to the activation or suppression of the inflammatory response during cellular stress. Future Directions: Emergent studies using molecule-mediated RNA splicing are being conducted to exploit the immunogenicity of AS protein products. Deciphering the mechanisms that connect misspliced OS and pathologies should remain a priority. Controlled release of RNA directly into cells with clinical applications is needed as the demand for innovative nucleic acid delivery systems continues to be demonstrated.

Liver Transplantation: A Test of Cellular Physiology, Preservation, and Injury

Liver transplantation has evolved into a mature clinical field, but scarcity of usable organs poses a unique challenge. Expanding the donor pool requires novel approaches for protecting hepatic physiology and cellular homeostasis. Here we define hepatocellular injury during transplantation, with an emphasis on modifiable cell death pathways as future therapeutics.

The Effects of Volatile Anesthetics on Early Clinical Outcomes in Liver Transplantation: A Systematic Review and Meta-Analysis

BACKGROUND

The aim of this systematic review and meta-analysis was to evaluate the effects of volatile anesthesia (VA) on early clinical outcomes in liver transplantation.

METHODS

We searched electronic databases to identify relevant studies comparing VA to non-VA in liver transplant recipients. The primary outcome assessed was early allograft dysfunction (EAD), and secondary outcomes were postoperative peak liver function tests (LFT) including aspartate transaminase (AST) and alanine transaminase (ALT) levels, and hospitalization time.

RESULTS

Six relevant studies involving 919 patients were analyzed. In meta-analysis of prospective studies, VA was associated with fewer incidence of EAD than non-VA (RR: 0.45; 95% CI: 0.25, 0.84; P = .012; I2 = 0%; Ph = 0.334) but this association was not significant in meta-analysis of retrospective studies (OR: 0.83; 95% CI: 0.58, 1.19; P = .310; I2 = 0%; Ph = 0.624). No significant difference in peak AST (SMD: -0.14 U/L; 95% CI: -0.65, 0.37 U/L; P = .594; I2 = 69.9%; Ph = 0.036) and ALT (SMD: -0.16 U/L; 95% CI: -0.65, 0.33 U/L; P = .529; I2 = 67.0%; Ph = 0.048) were found between VA and non-VA. The hospitalization time also did not differ between the two groups (SMD: -0.09 days; 95% CI: -0.29, 0.10 days; P = .350; I2 = 0%; Ph = 0.864).

CONCLUSIONS

While there is potential protective effect of VA against EAD in liver transplant recipients, certainty remains low, whereas VA was not associated with postoperative LFT or hospitalization time.

Beyond graft function impairment after liver transplantation: the prolonged cold ischemia time impact on recurrence of hepatocellular carcinoma after liver transplantation-a single-center retrospective study

Purpose

Hepatocellular carcinoma (HCC) is one of the malignant tumors responsible for high mortality and recurrence rates. Although liver transplantation (LT) is an effective treatment option for HCC, ischemia-reperfusion injury (IRI) is a contributor to HCC recurrence after LT. Moreover, prolonged cold ischemia time (CIT) is a risk factor for IRI during LT, and there is insufficient clinical evidence regarding the impact of CIT on HCC recurrence after LT.

Patients and Methods

This retrospective study analyzed 420 patients who underwent LT for HCC between February 2015 and November 2020 at The First Affiliated Hospital, Sun Yat-sen University. The duration of CIT was defined as the time from clamping of the donor aorta until portal reperfusion.

Results

A total of 133 patients (31.7%) experienced tumor recurrence after LT, and CIT > 568 min was the independent risk factor for HCC recurrence (OR, 2.406; 95% CI [1.371-4.220]; p = 0.002). Multivariate Cox's regression analysis revealed that the recipients' gender, exceeding Milan criteria, poor differentiation, and alpha-fetoprotein (AFP) ≥400 ng/ml in CIT > 568 min group were independent risk factors for disease-free survival. The peak 7-day postoperative alanine aminotransferase (ALT) level (p < 0.001), the peak 7-day postoperative aspartate aminotransferase (AST) level (p < 0.001), the peak 7-day postoperative peak total bilirubin (TBIL) level (p = 0.012), and the incidence of early allograft dysfunction (EAD) (p = 0.006) were significantly higher in the CIT > 568 min group compared to the CIT ≤ 568 min group. Moreover, the amount of fresh frozen plasma (FFP) infusion during the operation increased (p = 0.02), and the time of mechanical ventilation postoperative was longer (p = 0.045).

Conclusion

An effective strategy to improve the prognosis is to reduce CIT; this strategy lowers the recurrence of HCC in patients undergoing LT, especially those within the Milan criteria.

Drug delivery strategies for local immunomodulation in transplantation: Bridging the translational gap

Drug delivery strategies for local immunomodulation hold tremendous promise compared to current clinical gold-standard systemic immunosuppression as they could improve the benefit to risk ratio of life-saving or life-enhancing transplants. Such strategies have facilitated prolonged graft survival in animal models at lower drug doses while minimizing off-target effects. Despite the promising outcomes in preclinical animal studies, progression of these strategies to clinical trials has faced challenges. A comprehensive understanding of the translational barriers is a critical first step towards clinical validation of effective immunomodulatory drug delivery protocols proven for safety and tolerability in pre-clinical animal models. This review overviews the current state-of-the-art in local immunomodulatory strategies for transplantation and outlines the key challenges hindering their clinical translation.

Hypothermic Oxygenated machine PErfusion for high-risk liver grafts for transplantation: A systematic review and meta-analysis

BACKGROUND

Hypothermic Oxygenated machine PErfusion (HOPE) can reduce ischemic reperfusion injury and improve outcomes for liver transplant recipients. However, the effect of HOPE on high-risk extended criteria donor (ECD) and donation after circulatory death determination (DCDD) grafts is incomplete, despite the expectation that this cohort benefit maximally from HOPE. Accordingly, this paper aims to characterize the effect of HOPE on ECD and DCDD grafts.

METHODS

This study includes all papers comparing HOPE to static cold storage for high-risk ECD and DCDD grafts. Systematic searches of Medline, Embase, and Scopus were completed using the terms "HOPE" OR "hypothermic oxygenated machine perfusion" AND "liver transplantation". Data were extracted and analyzed using IBM SPSS to perform the meta-analysis.

RESULTS

A total of 2286 records were identified, with 10 meeting the inclusion criteria. Overall, the quality of evidence is heterogenous with many papers relying on retrospective controls. However, pooled analysis demonstrates HOPE to significantly reduce the rate of early allograft dysfunction, 12-month graft failure, re-transplantation, total biliary complications, and non-anastomotic strictures for high-risk grafts.

CONCLUSIONS

There is good evidence that HOPE improves outcomes following liver transplantation across a number of biochemical and clinical endpoints for high-risk grafts. Of note, the reduction in biliary complications and re-transplantation is particularly significant given the morbidity associated with these endpoints. However, further, high-quality prospective trials with contemporary controls and clinically relevant primary endpoints are needed to better define the impact of HOPE for this cohort of grafts.

Multimodal modulation of hepatic ischemia/reperfusion-induced injury by phytochemical agents: A mechanistic evaluation of hepatoprotective potential and safety profiles

BACKGROUND

Hepatic ischemia-reperfusion (I/R) injury is a clinically fundamental phenomenon that occurs through liver resection surgery, trauma, shock, and transplantation.

AIMS OF THE REVIEW

This review article affords an expanded and comprehensive overview of various natural herbal ingredients that have demonstrated hepatoprotective effects against I/R injury through preclinical studies in animal models.

MATERIALS AND METHODS

For the objective of this investigation, an extensive examination was carried out utilizing diverse scientific databases involving PubMed, Google Scholar, Science Direct, Egyptian Knowledge Bank (EKB), and Research Gate. The investigation was conducted based on specific identifiable terms, such as hepatic ischemia/reperfusion injury, liver resection and transplantation, cytokines, inflammation, NF-kB, interleukins, herbs, plants, natural ingredients, phenolic extract, and aqueous extract.

RESULTS

Bioactive ingredients derived from ginseng, curcumin, resveratrol, epigallocatechin gallate, quercetin, lycopene, punicalagin, crocin, celastrol, andrographolide, silymarin, and others and their effects on hepatic IRI were discussed. The specific mechanisms of action, signaling pathways, and clinical relevance for attenuation of liver enzymes, cytokine production, immune cell infiltration, oxidative damage, and cell death signaling in rodent studies are analyzed in depth. Their complex molecular actions involve modulation of pathways like TLR4, NF-κB, Nrf2, Bcl-2 family proteins, and others.

CONCLUSION

The natural ingredients have promising values in the protection and treatment of various chronic aggressive clinical conditions, and that need to be evaluated on humans by clinical studies.

Emerging roles of liquid-liquid phase separation in liver innate immunity

Biomolecular condensates formed by liquid-liquid phase separation (LLPS) have become an extensive mechanism of macromolecular metabolism and biochemical reactions in cells. Large molecules like proteins and nucleic acids will spontaneously aggregate and assemble into droplet-like structures driven by LLPS when the physical and chemical properties of cells are altered. LLPS provides a mature molecular platform for innate immune response, which tightly regulates key signaling in liver immune response spatially and physically, including DNA and RNA sensing pathways, inflammasome activation, and autophagy. Take this, LLPS plays a promoting or protecting role in a range of liver diseases, such as viral hepatitis, non-alcoholic fatty liver disease, liver fibrosis, hepatic ischemia-reperfusion injury, autoimmune liver disease, and liver cancer. This review systematically describes the whole landscape of LLPS in liver innate immunity. It will help us to guide a better-personalized approach to LLPS-targeted immunotherapy for liver diseases.

The Effect of Ascorbic Acid on Hepatic Ischaemia-Reperfusion Injury in Wistar Rats: An Experimental Study

Liver ischaemia-reperfusion (IR) during hepatic surgeries can lead to liver cell death via oxidative stress and the activation of immune cells, the release of cytokines, and damage-associated molecular patterns. Ascorbic acid has been shown to confer potential protective effects against IR injury, mainly due to its antioxidant properties. This study evaluated the effect of ascorbic acid infusion at different time points during hepatic IR in rats. Thirty-six male Wistar rats were divided into control and experimental groups that received the same total ascorbic acid dose at three different infusion times: before ischaemia, before reperfusion, or before both ischaemia and reperfusion. All of the animals experienced hepatic IR injury. We measured the hepatic enzymes, cytokines, and portal blood flow. Animals receiving ascorbic acid before both ischaemia and reperfusion had lower liver enzyme levels, reduced inflammation, and better portal venous flow than other animals. Divided doses of ascorbic acid before IR may be beneficial for reducing liver injury associated with IR.

Inhibition of cysteine-serine-rich nuclear protein 1 ameliorates ischemia-reperfusion injury during liver transplantation in an MAPK-dependent manner

Hepatic ischemia-reperfusion injury (HIRI) is a critical pathophysiological process during liver transplantation (LT). Multiple genes and signal pathways are dysregulated during HIRI. This study aims to identify genes as potential therapeutic targets for ameliorating HIRI. Datasets containing samples from the human donor liver (GSE151648) and mouse HIRI model (GSE117066) were analyzed to determine differentially expressed genes (DEGs). The selected DEGs were confirmed by real-time PCR and western blot in the hepatocyte hypoxia-reoxygenation (HR) model, mouse HIRI model, and human liver samples after transplantation. Genetic inhibition was used to further clarify the underlying mechanism of the gene in vitro and in vivo. Among the DEGs, CSRNP1 was significantly upregulated (|log FC|= 2.08, P < 0.001), and was positively correlated with the MAPK signal pathway (R = 0.67, P < 0.001). CSRNP1 inhibition by siRNA significantly suppressed apoptosis in the AML-12 cell line after HR (mean Annexin+ ratio = 60.62% vs 42.47%, P = 0.0019), but the protective effect was eliminated with an additional MAPK activator. Knocking down CSRNP1 gene expression by intravenous injection of AAV-shRNA markedly reduced liver injury in mouse HIRI model (ALT: AAV-NC vs AAV-shCsrnp1 = 26,673.5 ± 2761.2 vs 3839.7 ± 1432.8, P < 0.001; AST: AAV-NC vs AAV-shCsrnp1 = 8640.5 ± 1450.3 vs 1786.8 ± 518.3, P < 0.001). Liver-targeted delivery of siRNA by nanoparticles effectively inhibited intra-hepatic genetic expression of Csrnp1 and alleviated IRI by reducing tissue inflammation and hepatocyte apoptosis. Furthermore, CSRNP1 inhibition was associated with reduced activation of the MAPK pathway both in vitro and in vivo. In conclusion, our results demonstrated that CSRNP1 could be a potential therapeutic target to ameliorate HIRI in an MAPK-dependent manner.

HOPE Mitigates Ischemia-Reperfusion Injury in Ex-Situ Split Grafts: A Comparative Study With Living Donation in Pediatric Liver Transplantation

Optimizing graft preservation is key for ex-situ split grafts in pediatric liver transplantation (PSLT). Hypothermic Oxygenated Perfusion (HOPE) improves ischemia-reperfusion injury (IRI) and post-operative outcomes in adult LT. This study compares the use of HOPE in ex-situ partial grafts to static cold storage ex-situ partial grafts (SCS-Split) and to the gold standard living donor liver transplantation (LDLT). All consecutive HOPE-Split, SCS-Split and LDLT performed between 2018-2023 for pediatric recipients were included. Post-reperfusion syndrome (PRS, drop ≥30% in systolic arterial pressure) and reperfusion biopsies served as early indicators of IRI. We included 47 pediatric recipients (15 HOPE-Split, 17 SCS-Split, and 15 LDLT). In comparison to SCS-Split, HOPE-Split had a significantly shorter cold ischemia time (CIT) (470min vs. 538 min; p =0.02), lower PRS rates (13.3% vs. 47.1%; p = 0.04) and a lower IRI score (3 vs. 4; p = 0.03). The overall IRI score (3 vs. 3; p = 0.28) and PRS (13.3% vs. 13.3%; p = 1) after HOPE-Split were comparable to LDLT, despite a longer CIT (470 min vs. 117 min; p < 0.001). Surgical complications, one-year graft, and recipient survival did not differ among the groups. In conclusion, HOPE-Split mitigates early IRI in pediatric recipients in comparison to SCS-Split, approaching the gold standard of LDLT.

CX3CR1 deficiency promotes resolution of hepatic ischemia-reperfusion injury by regulating homeostatic function of liver infiltrating macrophages

Hepatic ischemia-reperfusion injury(HIRI) remains to be an unsolved risk factor that contributes to organ failure after liver surgery. Our clinical retrospective study showed that lower donor liver CX3-C chemokine receptor-1(CX3CR1) mRNA expression level were correlated with upregulated pro-resolved macrophage receptor MERTK, as well as promoted restoration efficiency of allograft injury in liver transplant. To further characterize roles of CX3CR1 in regulating resolution of HIRI, we employed murine liver partial warm ischemia-reperfusion model by Wt & Cx3cr1-/- mice and the reperfusion time was prolonged from 6 h to 4-7 days. Kupffer cells(KCs) were depleted by clodronate liposome(CL) in advance to focus on infiltrating macrophages, and repopulation kinetics were determined by FACS, IF and RNA-Seq. CX3CR1 antagonist AZD8797 was injected i.p. to interrogate potential pharmacological therapeutic strategies. In vitro primary bone marrow macrophages(BMMs) culture by LXR agonist DMHCA, as well as molecular and functional studies, were undertaken to dissect roles of CX3CR1 in modulating macrophages cytobiological development and resolutive functions. We observed that deficiency or pharmacological inhibition of CX3CR1 facilitated HIRI resolution via promoted macrophages migration in CCR1/CCR5 manner, as well as enhanced MerTK-mediated efferocytosis. Our study demonstrated the critical roles of CX3CR1 in progression of HIRI and identified it as a potential therapeutic target in clinical liver transplantation.

Exacerbated ischemia-reperfusion injury in fatty livers is mediated by lipid peroxidation stress and ferroptosis

BACKGROUND

Ischemia-reperfusion injury is a common problem in liver surgery and transplantation. Although ischemia-reperfusion injury is known to be more pronounced in fatty livers, the underlying mechanisms for this difference remain poorly understood. We hypothesized that ferroptosis plays a significant role in fatty liver ischemia-reperfusion injury due to increased lipid peroxidation in the presence of stored iron in the fatty liver. To test this hypothesis, the ferroptosis pathway was evaluated in a murine fatty liver ischemia-reperfusion injury model.

METHODS

C57BL6 mice were fed with a normal diet or a high fat, high sucrose diet for 12 weeks. At 22 weeks of age, liver ischemia-reperfusion injury was induced through partial (70%) hepatic pedicle clamping for 60 minutes, followed by 24 hours of reperfusion before tissue harvest. Acyl-coenzyme A synthetase long-chain family member 4 and 4-hydroxynonenal were quantified in the liver tissues. In separate experiments, liproxstatin-1 or vehicle control was administered for 7 consecutive days before liver ischemia-reperfusion injury.

RESULTS

Exacerbated ischemia-reperfusion injury was observed in the livers of high fat, high sucrose diet fed mice. High fat, high sucrose diet + ischemia-reperfusion injury (HDF+IRI) livers had a significantly greater abundance of acyl-coenzyme A synthetase long-chain family member 4 and 4-hydroxynonenal compared with normal diet + ischemia-reperfusion injury (ND+IRI) livers or sham fatty livers, which indicated an increase of ferroptosis. HFD fed animals receiving liproxstatin-1 injections had a significant reduction in serum aspartate transaminase and alanine transaminase after ischemia-reperfusion injury, consistent with attenuation of ischemia-reperfusion injury in the liver.

CONCLUSION

Ferroptosis plays a significant role in ischemia-reperfusion injury in fatty livers. Inhibiting ferroptotic pathways in the liver may serve as a novel therapeutic strategy to protect the fatty liver in the setting of ischemia-reperfusion injury.

Xa inhibitor edoxaban ameliorates hepatic ischemia-reperfusion injury via PAR-2-ERK 1/2 pathway

Hepatic ischemia-reperfusion injury causes liver damage during surgery. In hepatic ischemia-reperfusion injury, the blood coagulation cascade is activated, causing microcirculatory incompetence and cellular injury. Coagulation factor Xa (FXa)- protease-activated receptor (PAR)-2 signaling activates inflammatory reactions and the cytoprotective effect of FXa inhibitor in several organs. However, no studies have elucidated the significance of FXa inhibition on hepatic ischemia-reperfusion injury. The present study elucidated the treatment effect of an FXa inhibitor, edoxaban, on hepatic ischemia-reperfusion injury, focusing on FXa-PAR-2 signaling. A 60 min hepatic partial-warm ischemia-reperfusion injury mouse model and a hypoxia-reoxygenation model of hepatic sinusoidal endothelial cells were used. Ischemia-reperfusion injury mice and hepatic sinusoidal endothelial cells were treated and pretreated, respectively with or without edoxaban. They were incubated during hypoxia/reoxygenation in vitro. Cell signaling was evaluated using the PAR-2 knockdown model. In ischemia-reperfusion injury mice, edoxaban treatment significantly attenuated fibrin deposition in the sinusoids and liver histological damage and resulted in both anti-inflammatory and antiapoptotic effects. Hepatic ischemia-reperfusion injury upregulated PAR-2 generation and enhanced extracellular signal-regulated kinase 1/2 (ERK 1/2) activation; however, edoxaban treatment reduced PAR-2 generation and suppressed ERK 1/2 activation in vivo. In the hypoxia/reoxygenation model of sinusoidal endothelial cells, hypoxia/reoxygenation stress increased FXa generation and induced cytotoxic effects. Edoxaban protected sinusoidal endothelial cells from hypoxia/reoxygenation stress and reduced ERK 1/2 activation. PAR-2 knockdown in the sinusoidal endothelial cells ameliorated hypoxia/reoxygenation stress-induced cytotoxicity and suppressed ERK 1/2 phosphorylation. Thus, edoxaban ameliorated hepatic ischemia-reperfusion injury in mice by protecting against micro-thrombosis in sinusoids and suppressing FXa-PAR-2-induced inflammation in the sinusoidal endothelial cells.

Benefits of Hypothermic Oxygenated Perfusion Versus Static Cold Storage in Liver Transplant: A Comprehensive Systematic Review and Meta-analysis

Background

The magnitude of potential benefits that hypothermic oxygenated perfusion (HOPE) may provide for liver transplantation (LT) patients compared to static cold storage (SCS) remains uncertain. In this systematic review and meta-analysis, we aimed to investigate the therapeutic effect that HOPE can offer LT recipients relative to SCS by synthesizing available evidence.

Methods

A literature search was conducted in Embase, Medline, Web of Science, and the Cochrane database up to 1 June, 2023. The included studies were pooled for meta-analysis to synthesize their findings. Subgroup analysis was performed to investigate potential differences between HOPE and SCS for specific subgroups.

Results

A total of 11 studies comprising 1765 patients were included. Compared with SCS, HOPE was associated with a significant reduction in the incidence of early allograft dysfunction (EAD) (OR: 0.36, 95% CI: 0.26-0.50), as well as a noteworthy decrease in graft loss rate within one year (OR: 0.57, 95% CI: 0.33-0.97) and a lower occurrence of Clavien-Dindo grade IIIa or higher complications (OR: 0.62, 95% CI: 0.43-0.89). Subgroup analysis revealed that HOPE significantly reduced the one-year mortality rate, any biliary complications incidence, and acute rejection of transplanted liver rate in patients who received organs from donation after cardiac death (DCD).

Conclusions

HOPE has demonstrated efficacy in reducing the incidence of EAD after LT and shows some potential in diminishing postoperative complications such as biliary complications and acute rejection. This ultimately leads to improved patient prognosis, particularly among those receiving DCD grafts.

Ferroptosis: a new target for hepatic ischemia-reperfusion injury?

Ischemia-reperfusion injury (IRI) can seriously affect graft survival and prognosis and is an unavoidable event during liver transplantation. Ferroptosis is a novel iron-dependent form of cell death characterized by iron accumulation and overwhelming lipid peroxidation; it differs morphologically, genetically, and biochemically from other well-known cell death types (autophagy, necrosis, and apoptosis). Accumulating evidence has shown that ferroptosis is involved in the pathogenesis of hepatic IRI, and targeting ferroptosis may be a promising therapeutic approach. Here, we review the pathways and phenomena involved in ferroptosis, explore the associations and implications of ferroptosis and hepatic IRI, and discuss possible strategies for modulating ferroptosis to alleviate the hepatic IRI.

Bulk and single-cell RNA sequencing analysis with 101 machine learning combinations reveal neutrophil extracellular trap involvement in hepatic ischemia-reperfusion injury and early allograft dysfunction

BACKGROUND

Hepatic ischaemia-reperfusion injury (HIRI) is a major clinical concern during the perioperative period and is closely associated with early allograft dysfunction (EAD), acute rejection (AR) and long-term graft survival. Neutrophil extracellular traps (NETs) are extracellular structures formed by the release of decondensed chromatin and granular proteins following neutrophil stimulation. There is growing evidence that NETs are involved in the progression of various liver transplantation complications, including ischaemia-reperfusion injury (IRI). This study aimed to comprehensively analyse the expression patterns of NET-related genes (NRGs) in HIRI, identify HIRI subtypes with distinct characteristics, and develop a reliable EAD prediction model.

METHODS

Microarray, bulk RNA-seq, and single-cell sequencing datasets were obtained from the GEO database. Initially, differentially expressed NRGs (DE-NRGs) were identified using differential gene expression analyses. We then utilised a non-negative matrix factorisation (NMF) algorithm to classify HIRI samples. Subsequently, we employed machine learning algorithms to screen the hub NRGs related to EAD and developed an EAD prediction model based on these hub NRGs. Concurrently, we assessed the expression patterns of hub NRGs at the single-cell level using the HIRI. Additionally, we validated C5AR1 expression and its effect on HIRI and NETs formation in a rat orthotopic liver transplantation (OLT) model.

RESULTS

In this study, we identified 11 DE-NRGs in the HIRI context. Based on these 11 DE-NRGs, HIRI samples were classified into two distinct clusters. Cluster1 exhibited a low expression of DE-NRGs, minimal neutrophil infiltration, mild inflammation, and a low incidence of EAD. Conversely, Cluster2 displayed the opposite phenotype, with an activated inflammatory subtype and a higher incidence of EAD. Furthermore, an EAD prediction model was developed using the four hub NRGs associated with EAD. Based on risk scores, HIRI samples were classified into high- and low-risk groups. The OLT model confirmed substantial upregulation of C5AR1 expression in the liver tissue, accompanied by increased formation of NETs. Treatment with a C5AR1 antagonist improved liver function, reduced tissue inflammation, and decreased NETs formation.

CONCLUSIONS

This study distinguished two apparent HIRI subtypes, established a predictive model for EAD, and validated the effect of C5AR1 on HIRI. These findings provide novel perspectives for the development of advanced clinical strategies to enhance the outcomes of liver transplant recipients.

OXIDATIVE study: A pilot prospective observational cohort study protocol examining the influence of peri-reperfusion hyperoxemia and immune dysregulation on early allograft dysfunction after orthotopic liver transplantation

Early allograft dysfunction (EAD) is a functional hepatic insufficiency within a week of orthotopic liver transplantation (OLT) and is associated with morbidity and mortality. The etiology of EAD is multifactorial and largely driven by ischemia reperfusion injury (IRI), a phenomenon characterized by oxygen scarcity followed by paradoxical oxidative stress and inflammation. With the expanded use of marginal allografts more susceptible to IRI, the incidence of EAD may be increasing. This necessitates an in-depth understanding of the innate molecular mechanisms underlying EAD and interventions to mitigate its impact. Our central hypothesis is peri-reperfusion hyperoxemia and immune dysregulation exacerbate IRI and increase the risk of EAD. We will perform a pilot prospective single-center observational cohort study of 40 patients. The aims are to determine (1) the association between peri-reperfusion hyperoxemia and EAD and (2) whether peri-reperfusion perturbed cytokine, protein, and hypoxia inducible factor-1 alpha (HIF-1α) levels correlate with EAD after OLT. Inclusion criteria include age ≥ 18 years, liver failure, and donation after brain or circulatory death. Exclusion criteria include living donor donation, repeat OLT within a week of transplantation, multiple organ transplantation, and pregnancy. Partial pressure of arterial oxygen (PaO2) as the study measure allows for the examination of oxygen exposure within the confines of existing variability in anesthesiologist-administered fraction of inspired oxygen (FiO2) and the inclusion of patients with intrapulmonary shunting. The Olthoff et al. definition of EAD is the primary outcome. Secondary outcomes include postoperative acute kidney injury, pulmonary and biliary complications, surgical wound dehiscence and infection, and mortality. The goal of this study protocol is to identify EAD contributors that could be targeted to attenuate its impact and improve OLT outcomes. If validated, peri-reperfusion hyperoxemia and immune perturbations could be targeted via FiO2 titration to a goal PaO2 and/or administration of an immunomodulatory agent by the anesthesiologist intraoperatively.

Real-time monitoring of mitochondrial oxygenation during machine perfusion using resonance Raman spectroscopy predicts organ function

Organ transplantation is a life-saving procedure affecting over 100,000 people on the transplant waitlist. Ischemia reperfusion injury (IRI) is a major challenge in the field as it can cause post-transplantation complications and limit the use of organs from extended criteria donors. Machine perfusion technology has the potential to mitigate IRI; however, it currently fails to achieve its full potential due to a lack of highly sensitive and specific assays to assess organ quality during perfusion. We developed a real-time and non-invasive method of assessing organs during perfusion based on mitochondrial function and injury using resonance Raman spectroscopy. It uses a 441 nm laser and a high-resolution spectrometer to quantify the oxidation state of mitochondrial cytochromes during perfusion. This index of mitochondrial oxidation, or 3RMR, was used to understand differences in mitochondrial recovery of cold ischemic rodent livers during machine perfusion at normothermic temperatures with an acellular versus cellular perfusate. Measurement of the mitochondrial oxidation revealed that there was no difference in 3RMR of fresh livers as a function of normothermic perfusion when comparing acellular versus cellular-based perfusates. However, following 24 h of static cold storage, 3RMR returned to baseline faster with a cellular-based perfusate, yet 3RMR progressively increased during perfusion, indicating injury may develop over time. Thus, this study emphasizes the need for further refinement of a reoxygenation strategy during normothermic machine perfusion that considers cold ischemia durations, gradual recovery/rewarming, and risk of hemolysis.

Hippo (YAP)-autophagy axis protects against hepatic ischemia-reperfusion injury through JNK signaling

BACKGROUND

Hepatic ischemia-reperfusion injury (HIRI) remains a common complication during liver transplantation (LT) in patients. As a key downstream effector of the Hippo pathway, Yes-associated protein (YAP) has been reported to be involved in various physiological and pathological processes. However, it remains elusive whether and how YAP may control autophagy activation during ischemia-reperfusion.

METHODS

Human liver tissues from patients who had undergone LT were obtained to evaluate the correlation between YAP and autophagy activation. Both an in vitro hepatocyte cell line and in vivo liver-specific YAP knockdown mice were used to establish the hepatic ischemia-reperfusion models to determine the role of YAP in the activation of autophagy and the mechanism of regulation.

RESULTS

Autophagy was activated in the post-perfusion liver grafts during LT in patients, and the expression of YAP positively correlated with the autophagic level of hepatocytes. Liver-specific knockdown of YAP inhibited hepatocytes autophagy upon hypoxia-reoxygenation and HIRI ( P <0.05). YAP deficiency aggravated HIRI by promoting the apoptosis of hepatocytes both in the in vitro and in vivo models ( P <0.05). Attenuated HIRI by overexpression of YAP was diminished after the inhibition of autophagy with 3-methyladenine. In addition, inhibiting autophagy activation by YAP knockdown exacerbated mitochondrial damage through increasing reactive oxygen species ( P <0.05). Moreover, the regulation of autophagy by YAP during HIRI was mediated by AP1 (c-Jun) N-terminal kinase (JNK) signaling through binding to the transcriptional enhanced associate domain (TEAD).

CONCLUSIONS

YAP protects against HIRI by inducing autophagy via JNK signaling that suppresses the apoptosis of hepatocytes. Targeting Hippo (YAP)-JNK-autophagy axis may provide a novel strategy for the prevention and treatment of HIRI.

Sevoflurane preconditioning in living liver donation is associated with better initial graft function after pediatric transplantation: a retrospective study

INTRODUCTION

Initial allograft function determines the patient's immediate prognosis in pediatric liver transplantation. Ischemia-reperfusion injuries play a role in initial poor graft function (IPGF). In animal studies, preconditioning with inhaled anesthetic agents has demonstrated a protective effect on the liver. In humans, the few available studies are conflicting. This study assesses the association between the hypnotic agent used to maintain anesthesia during hepatectomy in living donors and the occurrence of IPGF after pediatric transplantation.

METHODS

We conducted a single-center retrospective analysis of children who received a living donor liver transplant (LDLT) between 2010 and 2019. We analyzed the incidence of EAD according to the hypnotic agent used to maintain general anesthesia during donor hepatectomy.

RESULTS

We included 183 pairs of patients (living donors-recipients). The anesthetics used in the donor were propofol (n = 85), sevoflurane (n = 69), or propofol with sevoflurane started 30 min before clamping (n = 29). Forty-two children (23%) developed IPGF. After multivariate logistic regression analysis, factors significantly associated with the occurrence of IPGF were the anesthesia maintenance agent used in the donor (p = 0.004), age of the donor (p = 0.03), duration of transplant surgery (p = 0.009), preoperative receiver neutrophil to lymphocyte ratio (p = 0.02), and albumin (p = 0.05).

CONCLUSION

Significantly fewer children who received a graft from a donor in whom only sevoflurane was used to maintain anesthesia developed IPGF. Although additional research is needed, this preconditioning strategy may provide an option to prevent IPGF after living liver donation.

Cold stress-induced ferroptosis in liver sinusoidal endothelial cells determines liver transplant injury and outcomes

Although cold preservation remains the gold standard in organ transplantation, cold stress-induced cellular injury is a significant problem in clinical orthotopic liver transplantation (OLT). Because a recent study showed that cold stress activates ferroptosis, a form of regulated cell death, we investigated whether and how ferroptosis determines OLT outcomes in mice and humans. Treatment with ferroptosis inhibitor (ferrostatin-1) during cold preservation reduced lipid peroxidation (malondialdehyde; MDA), primarily in liver sinusoidal endothelial cells (LSECs), and alleviated ischemia/reperfusion injury in mouse OLT. Similarly, ferrostatin-1 reduced cell death in cold-stressed LSEC cultures. LSECs deficient in nuclear factor erythroid 2-related factor 2 (NRF2), a critical regulator of ferroptosis, were susceptible to cold stress-induced cell death, concomitant with enhanced endoplasmic reticulum (ER) stress and expression of mitochondrial Ca2+ uptake regulator (MICU1). Indeed, supplementing MICU1 inhibitor reduced ER stress, MDA expression, and cell death in NRF2-deficient but not WT LSECs, suggesting NRF2 is a critical regulator of MICU1-mediated ferroptosis. Consistent with murine data, enhanced liver NRF2 expression reduced MDA levels, hepatocellular damage, and incidence of early allograft dysfunction in human OLT recipients. This translational study provides a clinically applicable strategy in which inhibition of ferroptosis during liver cold preservation mitigates OLT injury by protecting LSECs from peritransplant stress via an NRF2-regulatory mechanism.

Focusing on Ischemic Reperfusion Injury in the New Era of Dynamic Machine Perfusion in Liver Transplantation

Liver transplantation is the most effective treatment for end-stage liver disease. Transplant indications have been progressively increasing, with a huge discrepancy between the supply and demand of optimal organs. In this context, the use of extended criteria donor grafts has gained importance, even though these grafts are more susceptible to ischemic reperfusion injury (IRI). Hepatic IRI is an inherent and inevitable consequence of all liver transplants; it involves ischemia-mediated cellular damage exacerbated upon reperfusion and its severity directly affects graft function and post-transplant complications. Strategies for organ preservation have been constantly improving since they first emerged. The current gold standard for preservation is perfusion solutions and static cold storage. However, novel approaches that allow extended preservation times, organ evaluation, and their treatment, which could increase the number of viable organs for transplantation, are currently under investigation. This review discusses the mechanisms associated with IRI, describes existing strategies for liver preservation, and emphasizes novel developments and challenges for effective organ preservation and optimization.

Dimethyloxalylglycine pretreatment of living donor alleviates both donor and graft liver ischemia-reperfusion injury in rats

Background: Under the circumstance of the increasing waiting list for liver transplantation, living donor liver transplantation (LDLT) can alleviate the shortage of liver donors to some extent. However, how to reduce both donor and graft ischemia-reperfusion injury (IRI) is still an unsolved problem in LDLT. Hypoxia-induced transcription factor 1 (HIF1) activation is considered an important mechanism of cellular adaptation to hypoxia, and early activation of HIF1 may be a new way to alleviate liver IRI. Therefore, we aimed to investigate the impact of the HIF1 stabilizer dimethyloxalylglycine (DMOG) on IRI and the survival rate of donors and recipients of rat LDLT. Methods: Seventy percent partial liver resection and 30% partial liver transplantation were used to simulate donor and recipient of clinical LDLT. Rats were treated with DMOG (40 mg/kg) or with an equivalent amount of saline. The expression of HIF1 and downstream targets was analyzed after 2 h of reperfusion. Liver function and histopathology, apoptosis and oxidative stress levels were detected 6 h after reperfusion. At the same time, the 7-day survival rate of rats was calculated. Results: DMOG pretreatment significantly reduced IR-induced injury in the donor and recipient, which was manifested by reducing liver function damage and promoting tissue recovery. Meanwhile, compared with the untreated group, the oxidative stress level and the cell apoptosis rate were decreased in the group pretreated with DMOG. In addition, the transcription and expression of HIF1 target genes in the DMOG group were significantly enhanced. Remarkably, DMOG also increased the survival rate of the recipient. Conclusion: This study provides the first evidence that DMOG pretreatment of donors significantly alleviates liver IRI in both donors and recipients and increases the survival rate of recipients in LDLT. Therefore, DMOG may be a promising strategy for improving LDLT in the future.

Local Postoperative Graft Inflammation in Pancreas Transplant Patients With Early Graft Thrombosis

BACKGROUND

Graft thrombosis is the main cause of early graft loss following pancreas transplantation, and is more frequent in pancreas transplant alone (PTA) compared with simultaneous pancreas-kidney (SPK) recipients. Ischemia-reperfusion injury during transplantation triggers a local thromboinflammatory response. We aimed to evaluate local graft inflammation and its potential association with early graft thrombosis.

METHODS

In this observational study, we monitored 67 pancreas-transplanted patients using microdialysis catheters placed on the pancreatic surface during the first postoperative week. We analyzed 6 cytokines, interleukin-1 receptor antagonist (IL-1ra), IL-6, IL-8, interferon gamma-induced protein 10 (IP-10), macrophage inflammatory protein 1β (MIP-1β), IL-10, and the complement activation product complement activation product 5a (C5a) in microdialysis fluid. We compared the dynamic courses between patients with pancreas graft thrombosis and patients without early complications (event-free) and between PTA and SPK recipients. Levels of the local inflammatory markers, and plasma markers C-reactive protein, pancreas amylase, and lipase were evaluated on the day of thrombosis diagnosis compared with the first week in event-free patients.

RESULTS

IL-10 and C5a were not detectable. Patients with no early complications (n = 34) demonstrated high IL-1ra, IL-6, IL-8, IP-10, and MIP-1β concentrations immediately after surgery, which decreased to steady low levels during the first 2 postoperative days (PODs). Patients with early graft thrombosis (n = 17) demonstrated elevated IL-6 (P = 0.003) concentrations from POD 1 and elevated IL-8 (P = 0.027) concentrations from POD 2 and throughout the first postoperative week compared with patients without complications. IL-6 (P < 0.001) and IL-8 (P = 0.003) were higher on the day of thrombosis diagnosis compared with patients without early complications. No differences between PTA (n = 35) and SPK (n = 32) recipients were detected.

CONCLUSIONS

Local pancreas graft inflammation was increased in patients experiencing graft thrombosis, with elevated postoperative IL-6 and IL-8 concentrations, but did not differ between PTA and SPK recipients. Investigating the relationship between the local cytokine response and the formation of graft thrombosis warrants further research.

Real-time monitoring of mitochondrial oxygenation during machine perfusion using resonance Raman spectroscopy predicts organ function

Organ transplantation is a life-saving procedure affecting over 100,000 people on the transplant waitlist. Ischemia reperfusion injury is a major challenge in the field as it can cause post-transplantation complications and limits the use of organs from extended criteria donors. Machine perfusion technology is used to repair organs before transplant, however, currently fails to achieve its full potential due to a lack of highly sensitive and specific assays to predict organ quality during perfusion. We developed a real-time and non-invasive method of assessing organ function and injury based on mitochondrial oxygenation using resonance Raman spectroscopy. It uses a 441 nm laser and a high-resolution spectrometer to predict the oxidation state of mitochondrial cytochromes during perfusion, which vary due to differences in storage compositions and perfusate compositions. This index of mitochondrial oxidation, or 3RMR, was found to predict organ health based on clinically utilized markers of perfusion quality, tissue metabolism, and organ injury. It also revealed differences in oxygenation with perfusates that may or may not be supplemented with packed red blood cells as oxygen carriers. This study emphasizes the need for further refinement of a reoxygenation strategy during machine perfusion that is based on a gradual recovery from storage. Thus, we present a novel platform that provides a real-time and quantitative assessment of mitochondrial health during machine perfusion of livers, which is easy to translate to the clinic.

Disulfide-HMGB1 signals through TLR4 and TLR9 to induce inflammatory macrophages capable of innate-adaptive crosstalk in human liver transplantation

Ischemia-reperfusion injury (IRI) during orthotopic liver transplantation (OLT) contributes to graft rejection and poor clinical outcomes. The disulfide form of high mobility group box 1 (diS-HMGB1), an intracellular protein released during OLT-IRI, induces pro-inflammatory macrophages. How diS-HMGB1 differentiates human monocytes into macrophages capable of activating adaptive immunity remains unknown. We investigated if diS-HMGB1 binds toll-like receptor (TLR) 4 and TLR9 to differentiate monocytes into pro-inflammatory macrophages that activate adaptive immunity and promote graft injury and dysfunction. Assessment of 106 clinical liver tissue and longitudinal blood samples revealed that OLT recipients were more likely to experience IRI and graft dysfunction with increased diS-HMGB1 released during reperfusion. Increased diS-HMGB1 concentration also correlated with TLR4/TLR9 activation, polarization of monocytes into pro-inflammatory macrophages, and production of anti-donor antibodies. In vitro, healthy volunteer monocytes stimulated with purified diS-HMGB1 had increased inflammatory cytokine secretion, antigen presentation machinery, and reactive oxygen species production. TLR4 inhibition primarily impeded cytokine/chemokine and costimulatory molecule programs, whereas TLR9 inhibition decreased HLA-DR and reactive oxygen species production. diS-HMGB1-polarized macrophages also showed increased capacity to present antigens and activate T memory cells. In murine OLT, diS-HMGB1 treatment potentiated ischemia-reperfusion-mediated hepatocellular injury, accompanied by increased serum alanine transaminase levels. This translational study identifies the diS-HMGB1/TLR4/TLR9 axis as potential therapeutic targets in OLT-IRI recipients.

Role of intelligent/interactive qualitative and quantitative analysis-three-dimensional estimated model in donor-recipient size mismatch following deceased donor liver transplantation

BACKGROUND

Donor-recipient size mismatch (DRSM) is considered a crucial factor for poor outcomes in liver transplantation (LT) because of complications, such as massive intraoperative blood loss (IBL) and early allograft dysfunction (EAD). Liver volumetry is performed routinely in living donor LT, but rarely in deceased donor LT (DDLT), which amplifies the adverse effects of DRSM in DDLT. Due to the various shortcomings of traditional manual liver volumetry and formula methods, a feasible model based on intelligent/interactive qualitative and quantitative analysis-three-dimensional (IQQA-3D) for estimating the degree of DRSM is needed.

AIM

To identify benefits of IQQA-3D liver volumetry in DDLT and establish an estimation model to guide perioperative management.

METHODS

We retrospectively determined the accuracy of IQQA-3D liver volumetry for standard total liver volume (TLV) (sTLV) and established an estimation TLV (eTLV) index (eTLVi) model. Receiver operating characteristic (ROC) curves were drawn to detect the optimal cut-off values for predicting massive IBL and EAD in DDLT using donor sTLV to recipient sTLV (called sTLVi). The factors influencing the occurrence of massive IBL and EAD were explored through logistic regression analysis. Finally, the eTLVi model was compared with the sTLVi model through the ROC curve for verification.

RESULTS

A total of 133 patients were included in the analysis. The Changzheng formula was accurate for calculating donor sTLV (P = 0.083) but not for recipient sTLV (P = 0.036). Recipient eTLV calculated using IQQA-3D highly matched with recipient sTLV (P = 0.221). Alcoholic liver disease, gastrointestinal bleeding, and sTLVi > 1.24 were independent risk factors for massive IBL, and drug-induced liver failure was an independent protective factor for massive IBL. Male donor-female recipient combination, model for end-stage liver disease score, sTLVi ≤ 0.85, and sTLVi ≥ 1.32 were independent risk factors for EAD, and viral hepatitis was an independent protective factor for EAD. The overall survival of patients in the 0.85 < sTLVi < 1.32 group was better compared to the sTLVi ≤ 0.85 group and sTLVi ≥ 1.32 group (P < 0.001). There was no statistically significant difference in the area under the curve of the sTLVi model and IQQA-3D eTLVi model in the detection of massive IBL and EAD (all P > 0.05).

CONCLUSION

IQQA-3D eTLVi model has high accuracy in predicting massive IBL and EAD in DDLT. We should follow the guidance of the IQQA-3D eTLVi model in perioperative management.

Heme Oxygenase-1-Modified BMMSCs Activate AMPK-Nrf2-FTH1 to Reduce Severe Steatotic Liver Ischemia-Reperfusion Injury

BACKGROUND

Ischemia-reperfusion injury (IRI) is an important cause of graft dysfunction post-liver transplantation, where donor liver with severe steatosis is more sensitive to IRI. Liver IRI involves ferroptosis and can be alleviated by heme oxygenase-1-modified bone marrow mesenchymal stem cells (HO-1/BMMSCs).

AIMS

To explore the role and mechanism of HO-1/BMMSCs in severe steatotic liver IRI.

METHODS

A severe steatotic liver IRI rat model and a hypoxia/reoxygenation (H/R) of severe steatosis hepatocyte model were established. Liver and hepatocyte damage was evaluated via liver histopathology and cell activity. Ferroptosis was evaluated through ferroptosis indexes. Nuclear factor erythroid 2-related factor 2 (Nrf2) was knocked down in severe steatotic hepatocytes. The role of Nrf2 and AMPK in HO-1/BMMSC inhibition of ferroptosis was examined using the AMP-activated protein kinase (AMPK) pathway inhibitor Compound C.

RESULTS

The HO-1/BMMSCs alleviated severe steatotic liver IRI and ferroptosis. HO-1/BMMSCs promoted ferritin heavy chain 1(FTH1), Nrf2, and phosphorylated (p)-AMPK expression in the H/R severe steatotic hepatocytes. Nrf2 knockdown decreased FTH1 expression levels but did not significantly affect p-AMPK expression levels. The protective effect of HO-1/BMMSCs against H/R injury in severe steatotic hepatocytes and the inhibitory effect on ferroptosis were reduced. Compound C decreased p-AMPK, Nrf2, and FTH1 expression levels, weakened the HO-1/BMMSC protective effect against severe steatotic liver IRI and H/R-injured severe steatotic hepatocytes, and reduced the inhibition of ferroptosis.

CONCLUSIONS

Ferroptosis was involved in HO-1/BMMSC reduction of severe steatotic liver IRI. HO-1/BMMSCs protected against severe steatotic liver IRI by inhibiting ferroptosis through the AMPK-Nrf2-FTH1 pathway. HO-1/BMMSCs activate AMPK, which activates Nrf2, promotes its nuclear transcription, then promotes the expression of its downstream protein FTH1, thereby inhibiting ferroptosis and attenuating severe steatotic liver IRI in rats. Glu: glutamic acid; Cys: cystine; GSH: glutathione; GPX4: glutathione peroxidase 4; HO-1/BMMSCs: HO-1-modified BMMSCs; Fer-1: ferrostatin-1; DFO: deferoxamine; FTH1: ferritin heavy chain1; p-AMPK: phosphorylated AMP-activated protein kinase; Nrf2: nuclear factor erythroid 2-related factor 2; IRI: ischemia-reperfusion injury; MCD: methionine-choline deficiency.

Impact of Portable Normothermic Machine Perfusion for Liver Transplantation From Adult Deceased Donors

OBJECTIVE

To assess how liver allografts preserved using portable normothermic machine perfusion (NMP) compare against those that underwent ischemic cold storage (ICS) in the setting of donation after brain death (DBD) and donation after circulatory death (DCD) liver transplantation (LT).

BACKGROUND

Compared with conventional ICS, NMP may offer more homeostatic preservation, permit physiological assessment of organ function, and provide opportunities for graft improvement/modification. We report a single-center US experience of liver NMP.

METHODS

A single-center, retrospective analysis of collected data on 541 adult whole LTs from 469 DBD donors [NMP (n = 58) vs ICS (n = 411)] and 72 DCD donors [NMP (n = 52) vs ICS (n = 20)] between January 2016 and December 2022.

RESULTS

In DBD LT, male sex [odds ratio (95% CI): 1.83 (1.08-3.09)] and >10% macrosteatosis of the donor liver [1.85 (1.10-3.10)] were statistically significant independent risk factors of early allograft dysfunction (EAD). Donor age >40 years and cold ischemia time >7 hours were independent risk factors of reperfusion syndrome (RPS). One-year, 3-year, and 5-year incidences of ischemic cholangiopathy (IC) did not differ significantly in DBD cases between the NMP and ICS cohorts. In DCD LT, NMP was an independent protective factor against EAD [0.11 (0.03-0.46)] and RPS [0.04 (0.01-0.25)]. The incidence of IC in the DCD cases at 1-year and 3-year time points was significantly lower in the NMP cohort (1.9% compared with 20% in the ICS group).

CONCLUSIONS

Compared with conventional ICS, NMP can significantly reduce the incidence of EAD, RPS, and IC after DCD LT.

T Cell CEACAM1-TIM-3 Crosstalk Alleviates Liver Transplant Injury in Mice and Humans

BACKGROUND & AIMS

Carcinoembryonic antigen-related cell adhesion molecule 1 (CC1) acts through homophilic and heterophilic interactions with T cell immunoglobulin domain and mucin domain-containing protein 3 (TIM-3), which regulates innate immune activation in orthotopic liver transplantation (OLT). We investigated whether cluster of differentiation (CD) 4+ T cell-dependent CC1-TIM-3 crosstalk may affect OLT outcomes in mice and humans.

METHODS

Wild-type (WT) and CC1-deficient (CC1 knock-out [KO]) mouse livers were transplanted into WT, CC1KO, or T-cell TIM-3 transgenic (TIM-3Tg)/CC1KO double-mutant recipients. CD4+ T cells were adoptively transferred into T/B cell-deficient recombination activating gene 2 protein (Rag2) KO recipients, followed by OLT. The perioperative liver-associated CC1 increase was analyzed in 50 OLT patients.

RESULTS

OLT injury in WT livers deteriorated in CC1KO compared with CC1-proficient (WT) recipients. The frequency of TIM-3+CD4+ T cells was higher in WT than CC1KO hosts. Reconstitution of Rag2KO mice with CC1KO-T cells increased nuclear factor (NF)-κB phosphorylation and OLT damage compared with recipients repopulated with WT T cells. T-cell TIM-3 enhancement in CC1KO recipients (WT → TIM3Tg/CC1KO) suppressed NF-κB phosphorylation in Kupffer cells and mitigated OLT injury. However, TIM-3-mediated protection was lost by pharmacologic TIM-3 blockade or an absence of CC1 in the donor liver (CC1KO → TIM-3Tg/CC1KO). The perioperative CC1 increase in human OLT reduced hepatocellular injury, early allograft dysfunction, and the cumulative rejection rate.

CONCLUSIONS

This translational study identifies T cell-specific CC1 signaling as a therapeutic means to alleviate OLT injury by promoting T cell-intrinsic TIM-3, which in turn interacts with liver-associated CC1 to suppress NF-κB in Kupffer cells. By suppressing peritransplant liver damage, promoting T-cell homeostasis, and improving OLT outcomes, recipient CC1 signaling serves as a novel cytoprotective sentinel.

Trans-anethole pretreatment ameliorates hepatic ischemia-reperfusion injury via regulation of soluble epoxide hydrolase

Hepatic ischemia reperfusion injury (IRI) is a risk factor for early graft nonfunction and graft rejection after liver transplantation (LT). The process of liver IRI involves inflammatory response, oxidative stress, apoptosis and other pathophysiological processes. So far, there is still a lack of effective drugs to ameliorate liver IRI. Trans-anethole (TA) is an aromatic compound. Many medications as well as natural foods contain TA. TA has multiple effects such as anti-inflammation, anti-oxidative stress and anti-apoptosis. However, the mechanism of TA pretreatment in liver IRI is unclear. The mice hepatic IRI model was constructed after gavage pretreatment with TA (10 mg/kg, 20 mg/kg, 40 mg/kg) for 7 consecutive days. Our study confirmed that TA pretreatment significantly improve liver function and reduce serum AST, ALT in hepatic IRI. HE staining showed that TA pretreatment alleviated liver injury. Meanwhile, TA (20 mg/kg) pretreatment attenuated hepatocyte apoptosis in hepatic IRI. In addition, TA (20 mg/kg) pretreatment reduced the inflammatory factors TNF-α, IL-6 and infiltration of CD11b positive cells in liver tissues during hepatic IRI in mice. TA pretreatment also alleviated oxidative stress in mice hepatic IRI. Our study further indicated that TA pretreatment attenuated mice hepatic IRI through inhibiting NLRP3 inflammasome activation via regulation of soluble epoxide hydrolase (sEH). This study provides a novel and effective potential drug with few side effects for easing liver IRI.