Ischemia-reperfusion injury and the risk of hepatocellular carcinoma recurrence after deceased donor liver transplantation

A novel nomogram to predict the recurrence of hepatocellular carcinoma after liver transplantation using extended selection criteria

BACKGROUND

Liver transplantations (LTs) with extended criteria have produced surgical results comparable to those obtained with traditional standards. However, it is not sufficient to predict hepatocellular carcinoma (HCC) recurrence after LT according to morphological criteria alone. The present study aimed to construct a nomogram for predicting HCC recurrence after LT using extended selection criteria.

METHODS

Retrospective data on patients with HCC, including pathology, serological markers and follow-up data, were collected from January 2015 to April 2020 at Huashan Hospital, Fudan University, Shanghai, China. Logistic least absolute shrinkage and selection operator (LASSO) regression and multivariate Cox regression analyses were performed to identify and construct the prognostic nomogram. Receiver operating characteristic (ROC) curves, Kaplan-Meier curves, decision curve analyses (DCAs), calibration diagrams, net reclassification indices (NRIs) and integrated discrimination improvement (IDI) values were used to assess the prognostic capacity of the nomogram.

RESULTS

A total of 301 patients with HCC who underwent LT were enrolled in the study. The nomogram was constructed, and the ROC curve showed good performance in predicting survival in both the development set (2/3) and the validation set (1/3) (the area under the curve reached 0.748 and 0.716, respectively). According to the median value of the risk score, the patients were categorized into the high- and low-risk groups, which had significantly different recurrence-free survival (RFS) rates (P < 0.01). Compared with the Milan criteria and University of California San Francisco (UCSF) criteria, DCA revealed that the new nomogram model had the best net benefit in predicting 1-, 3- and 5-year RFS. The nomogram performed well for calibration, NRI and IDI improvement.

CONCLUSIONS

The nomogram, based on the Milan criteria and serological markers, showed good accuracy in predicting the recurrence of HCC after LT using extended selection criteria.

The role of cold ischemia time and hypothermic perfusion in predicting early hepatocellular carcinoma recurrences after liver transplantation

AIM

The aim of the study was to identify predictors of early tumor recurrence in patients with hepatocellular carcinoma (HCC) after liver transplantation (LT).

METHODS

Retrospective cohort study in 237 consecutive liver recipients with HCC between 2016 and 2021. Multivariate logistic analysis was performed to identify predictors of early HCC recurrences. The impact of hypothermic-oxygenated perfusion (HOPE) on outcome was analyzed after propensity score weighting.

RESULTS

Early recurrences were observed in 15 cases. Microvascular invasion (OR 3.737, 95% CI 1.246-11.206, p = 0.019) and cold ischemia time (OR 1.155, 95% CI 1.001-1.333, p = 0.049) were independently associated with a lower risk of HCC recurrences. After balancing for relevant variables, patients in the HOPE group had lower rates of tumor recurrence (weighted OR 0.126, 95% CI 0.016-0.989, p = 0.049) and higher recurrence free survival (weighted HR 0.132, 95% CI 0.017-0.999, p = 0.050).

CONCLUSION

Reducing cold ischemia time and graft perfusion with HOPE can lead to lower rates of early HCC recurrences and higher recurrence-free survival.

Oncologic Outcomes of Interventions to Decrease Allograft Ischemia-Reperfusion Injury within Patients Undergoing Liver Transplantation for Hepatocellular Carcinoma: A Systematic Review

Ischemia-reperfusion injury (IRI) during liver transplantation has been implicated in the recurrence of hepatocellular carcinoma (HCC). This systematic review aimed to evaluate interventions to reduce IRI during liver transplantation for HCC and their impact on oncologic outcomes. A comprehensive literature search retrieved four retrospective studies involving 938 HCC patients, utilising interventions such as post-operative prostaglandin administration, hypothermic machine perfusion, and normothermic machine perfusion. Overall, treated patients exhibited reduced post-operative hepatocellular injury and inflammation and significantly enhanced recurrence-free survival. Despite these promising results, the impact of these interventions on overall survival remains unclear. This underscores the imperative for further prospective research to comprehensively understand the efficacy of these interventions in HCC patients undergoing transplantation. The findings highlight the potential benefits of these strategies while emphasising the need for continued investigation into their overall impact.

Postoperative lenvatinib + PD-1 blockade reduces early tumor recurrence in hepatocellular carcinoma with microvascular invasion (Barcelona Clinic Liver Cancer stage 0 or A): a propensity score matching analysis

BACKGROUND

This study aimed to determine the effectiveness of postoperative adjuvant lenvatinib + PD-1 blockade for patients with early-stage hepatocellular carcinoma (HCC) with microvascular invasion (MVI).

METHODS

A total of 393 patients with HCC (Barcelona Clinic Liver Cancer stage 0 or A) who underwent curative hepatectomy with histopathologically proven MVI were enrolled according to the inclusion and exclusion criteria and assigned to 2 groups: surgery alone (surgery-alone group) and surgery with lenvatinib and PD-1 blockade (surgery + lenvatinib + PD-1 group) to compare recurrence-free survival (RFS), overall survival (OS), recurrence type, and annual recurrence rate after the application of propensity score matching (PSM). The Cox proportional hazards model was used for univariate and multivariate analyses.

RESULTS

Overall, 99 matched pairs were selected using PSM. Patients in the surgery + lenvatinib + PD-1 group had significantly higher 3-year RFS rates (76.8%, 65.7%, and 53.5%) than patients in the surgery-alone group (60.6%, 45.5%, and 37.4%) (P = .012). The 2 groups showed no significant difference in recurrence types and OS. Surgery alone, MVI-M2, and alpha-fetoprotein of ≥200 ng/mL were independent risk factors for RFS (P < .05), and history of alcohol use disorder was an independent risk factor for OS (P = .022).

CONCLUSION

Postoperative lenvatinib + PD-1 blockade improved the RFS in patients with HCC with MVI and was particularly beneficial for specific individuals.

Effect of intermittent Pringle maneuver on perioperative outcomes and long-term survival following liver resection in patients with hepatocellular carcinoma: a meta-analysis and systemic review

BACKGROUND

Intermittent Pringle maneuver (IPM) is commonly used to control bleeding during liver resection. IPM can cause ischemia-reperfusion injury, which may affect the prognosis of patients with hepatocellular carcinoma (HCC). The present meta-analysis was conducted to evaluate the effect of IPM use on perioperative outcomes and long-term survival in patients with HCC.

METHODS

A systemic literature search was performed in the PubMed, Embase, Web of Science, and Cochrane Library databases to identify randomized controlled trials and retrospective studies that compared the effect of IPM with no Pringle maneuver during liver resection in patients with HCC. Hazard ratio (HR), risk ratio, standardized mean difference, and their 95% confidence interval (CI) values were calculated based on the type of variables.

RESULTS

This meta-analysis included nine studies comprising one RCT and eight retrospective studies and involved a total of 3268 patients. Perioperative outcomes, including operation time, complications, and length of hospital stay, except for blood loss, were comparable between the two groups. After removing the studies that led to heterogeneity, the results showed that IPM was effective in reducing blood loss. Five studies reported overall survival (OS) and disease-free survival (DFS) data and eight studies reported perioperative outcomes. No significant difference in OS and DFS was observed between the two groups (OS: HR, 1.01; 95% CI, 0.85-1.20; p = 0.95; DFS: HR, 1.01; 95% CI, 0.88-1.17; p = 0.86).

CONCLUSION

IPM is a useful technique to control blood loss during liver resection and does not affect the long-term survival of patients with HCC.

The tumor microenvironment in the postsurgical liver: Mechanisms and potential targets of postoperative recurrence in human hepatocellular carcinoma

Surgery remains to be the mainstay of treatment for hepatocellular carcinoma (HCC). Nonetheless, its therapeutic efficacy is significantly impaired by postoperative recurrence, which occurs in more than half of cases as a result of intrahepatic metastasis or de novo tumorigenesis. For decades, most therapeutic strategies on inhibiting postoperative HCC recurrence have been focused on the residual tumor cells but satisfying therapeutic outcomes are barely observed in the clinic. In recent years, a better understanding of tumor biology allows us to shift our focus from tumor cells toward the postoperative tumor microenvironment (TME), which is gradually identified to play a pivotal role in tumor recurrence. In this review, we describe various surgical stress and surgical perturbation on postoperative TME. Besides, we discuss how such alternations in TME give rise to postoperative recurrence of HCC. Based on its clinical significance, we additionally highlight the potential of the postoperative TME as a target for postoperative adjuvant therapeutics.

Live-imaging studies reveal how microclots and the associated inflammatory response enhance cancer cell extravasation

Previous clinical studies and work in mouse models have indicated that platelets and microclots might enable the recruitment of immune cells to the pre-metastatic cancer niche, leading to efficacious extravasation of cancer cells through the vessel wall. Here, we investigated the interaction between platelets, endothelial cells, inflammatory cells, and engrafted human and zebrafish cancer cells by live-imaging studies in translucent zebrafish larvae, and show how clotting (and clot resolution) act as foci and as triggers for extravasation. Fluorescent tagging in each lineage revealed their dynamic behaviour and potential roles in these events, and we tested function by genetic and drug knockdown of the contributing players. Morpholino knockdown of fibrinogen subunit α (fga) and warfarin treatment to inhibit clotting both abrogated extravasation of cancer cells. The inflammatory phenotype appeared fundamental, and we show that forcing a pro-inflammatory, tnfa-positive phenotype is inhibitory to extravasation of cancer cells.

Risk Factors of Positive Resection Margin in Hepatectomy for Resectable Ruptured Hepatocellular Carcinoma: Risk Prediction and Prognosis

BACKGROUND AND AIM

Clinical work has revealed that hepatectomy for resectable ruptured hepatocellular carcinoma (rHCC) has a relatively high percentage of positive resection margins found in postoperative pathology. It is necessary to evaluate the risk factors associated with R1 resection in patients undergoing hepatectomy for rHCC.

METHODS

A total of 408 patients with resectable rHCC originating from three centers undergoing surgery from January 2012 to January 2020 were consecutively enrolled in the study to study the prognostic impact of R1 resection using Kaplan-Meier plotting of survival curves. One center with 280 served as the training group, and the other two centers served as the validation group. Multivariate logistic regression analysis screened for variables affecting R1 and developed prediction models, and the models were tested in the validation cohort using the receiver operating characteristic curves (ROC) and calibration curves.

RESULTS

The prognosis of rHCC patients with positive cut margins was worse than that of patients with R0 resection. Risk factors for R1 resection were tumor max length (OR = 2.668 [1.161-6.131]), microvascular invasion (MVI) (OR = 3.655 [1.766-7.566]), times of hepatic inflow occlusion (1/0:OR = 2.213 [1.113-4.399]; 2/0:OR = 5.723 [2.010-8.289]) and timing of hepatectomy (OR = 5.284 [2.394-9.661]), using tumor max length, times of HIO, and timing of hepatectomy to construct the nomogram, the area under the curve of the model was 0.810 (0.781-0.842) and 0.782 (0.752-0.805) in the training and validation groups, respectively, and the calibration curve of the model was basically on the 45° line.

CONCLUSIONS

This study constructs a clinical model to predict R1 resection after hepatectomy for resectable rHCC, which can be used to better plan perioperative strategies for the incidence of R1 resection during hepatectomy.

FOXO1 regulates Th17 cell-mediated hepatocellular carcinoma recurrence after hepatic ischemia-reperfusion injury

BACKGROUND

Hepatic ischemia-reperfusion injury (IRI) is considered as an effecting factor for hepatocellular carcinoma (HCC) recurrence. Th17/Treg cells are a pair of essential components in adaptive immune response in liver IRI, and forkhead box O1 (FOXO1) has the properties of maintaining the function and phenotype of immune cells. Herein, we illuminated the correlation and function between Th17/Treg cell balance and FOXO1 in IRI-induced HCC recurrence.

METHODS

RNA sequencing was performed on naive CD4+ T cells from normal and IRI model mice to identify relevant transcription factors. Western blotting, qRT-PCR, immunohistochemical staining, and flow cytometry were performed in IRI models to indicate the effect of FOXO1 on the polarization of Th17/Treg cells. Then, transwell assay of HCC cell migration and invasion, clone formation, wound healing assay, and Th17 cells adoptively transfer was utilized to assess the function of Th17 cells in IRI-induced HCC recurrence in vitro and in vivo.

RESULTS

Owning to the application of RNA sequencing, FOXO1 was screened and assumed to perform a significant function in hepatic IRI. The IRI model demonstrated that up-regulation of FOXO1 alleviated IR stress by attenuating inflammatory stress, maintaining microenvironment homeostasis, and reducing the polarization of Th17 cells. Mechanistically, Th17 cells accelerated IRI-induced HCC recurrence by shaping the hepatic pre-metastasis microenvironment, activating the EMT program, promoting cancer stemness and angiogenesis, while the upregulation of FOXO1 can stabilize the liver microenvironment homeostasis and alleviate the negative effects of Th17 cells. Moreover, the adoptive transfer of Th17 cells in vivo revealed its inducing function in IRI-induced HCC recurrence.

CONCLUSIONS

These results indicated that FOXO1-Th17/Treg axis exerts a crucial role in IRI-mediated immunologic derangement and HCC recurrence, which could be a promising target for reducing the HCC recurrence after hepatectomy. Liver IRI affects the balance of Th17/Treg cells by inhibiting the expression of FOXO1, and the increase of Th17 cells has the ability to induce HCC recurrence through EMT program, cancer stemness pathway, the formation of premetastatic microenvironment and angiogenesis.

Hepatic venous territory mapping in living donor liver transplantation using right liver graft: an objective parameter for venous reconstruction

Purpose

This study evaluated the clinical implication of hepatic venous territory mapping in living donor liver transplantation.

Methods

Living donor liver transplantations performed using right graft since 2017 were included. Hepatic venous volume mapping was started in 2019. Risk factors for graft failure and overall survival were analyzed. Analysis for factors related to occlusion of reconstructed vein was performed.

Results

Among 445 patients included, 213 underwent hepatic venous mapping. Hepatic venous mapping itself was not a significant factor for graft (hazard ratio [HR], 0.958; 95% confidence interval [CI], 0.441-2.082; P = 0.913) and overall survival (HR, 0.627; 95% CI, 0.315-1.247; P = 0.183). Inferior hepatic vein occlusion was a significant risk factor for both graft survival (HR, 8.795; 95% CI, 1.628-47.523; P = 0.012) and overall survival (HR, 11.13; 95% CI, 2.460-50.300; P = 0.002). In a subgroup with middle hepatic vein reconstruction, occlusion was a significant risk factor for overall survival (HR, 3.289; 95% CI, 1.304-8.296; P = 0.012). In patients with middle hepatic vein reconstruction whose venous territory volumes were measured, right anterior volume of ≥300 cm³ was protective for vein occlusion (OR, 0.317; 95% CI, 0.152-0.662; P = 0.002). In patients with V5 reconstruction, V5 volume of ≥150 cm³ was protective for vein occlusion (OR, 0.253; 95% CI, 0.087-0.734; P = 0.011).

Conclusion

Inferior and middle hepatic vein reconstruction has significant impact on clinical outcome. Hepatic venous territory mapping can provide an objective measure for successful reconstruction of venous branches.

Impact of Hypothermic Oxygenated Machine Perfusion on Hepatocellular Carcinoma Recurrence after Liver Transplantation

BACKGROUND

Machine perfusion may be able to mitigate ischemia-reperfusion injury (IRI), which increases hepatocellular carcinoma (HCC) recurrence after liver transplantation (LT). This study aimed to investigate the impact of dual-hypothermic oxygenated machine perfusion (D-HOPE) on HCC recurrence in LT.

METHODS

A single-center retrospective study was conducted from 2016 to 2020. Pre- and postoperative data of HCC patients undergoing LT were analyzed. Recipients of a D-HOPE-treated graft were compared to those of livers preserved using static cold storage (SCS). The primary endpoint was recurrence-free survival (RFS).

RESULTS

Of 326 patients, 246 received an SCS-preserved liver and 80 received a D-HOPE-treated graft (donation after brain death (DBD), n = 66; donation after circulatory death (DCD), n = 14). Donors of D-HOPE-treated grafts were older and had higher BMI. All DCD donors were treated by normothermic regional perfusion and D-HOPE. The groups were comparable in terms of HCC features and estimated 5-year RFS according to the Metroticket 2.0 model. D-HOPE did not reduce HCC recurrence (D-HOPE 10%; SCS 8.9%; p = 0.95), which was confirmed using Bayesian model averaging and inverse probability of treatment weighting-adjusted RFS analysis. Postoperative outcomes were comparable between groups, except for lower AST and ALT peak in the D-HOPE group.

CONCLUSIONS

In this single-center study, D-HOPE did not reduce HCC recurrence but allowed utilizing livers from extended criteria donors with comparable outcomes, improving access to LT for patients suffering from HCC.

Preservation of Mitochondrial Health in Liver Ischemia/Reperfusion Injury

Liver ischemia-reperfusion injury (LIRI) is a major cause of the development of complications in different clinical settings such as liver resection and liver transplantation. Damage arising from LIRI is a major risk factor for early graft rejection and is associated with higher morbidity and mortality after surgery. Although the mechanisms leading to the injury of parenchymal and non-parenchymal liver cells are not yet fully understood, mitochondrial dysfunction is recognized as a hallmark of LIRI that exacerbates cellular injury. Mitochondria play a major role in glucose metabolism, energy production, reactive oxygen species (ROS) signaling, calcium homeostasis and cell death. The diverse roles of mitochondria make it essential to preserve mitochondrial health in order to maintain cellular activity and liver integrity during liver ischemia/reperfusion (I/R). A growing body of studies suggest that protecting mitochondria by regulating mitochondrial biogenesis, fission/fusion and mitophagy during liver I/R ameliorates LIRI. Targeting mitochondria in conditions that exacerbate mitochondrial dysfunction, such as steatosis and aging, has been successful in decreasing their susceptibility to LIRI. Studying mitochondrial dysfunction will help understand the underlying mechanisms of cellular damage during LIRI which is important for the development of new therapeutic strategies aimed at improving patient outcomes. In this review, we highlight the progress made in recent years regarding the role of mitochondria in liver I/R and discuss the impact of liver conditions on LIRI.

Postoperative Supplemental Oxygen in Liver Transplantation (PSOLT) does not reduce the rate of infections: results of a randomized controlled trial

BACKGROUND

Despite inconsistent evidence, international guidelines underline the importance of perioperative hyperoxygenation in prevention of postoperative infections. Further, data on safety and efficacy of this method in liver transplant setting are lacking. The aim was to evaluate efficacy and safety of postoperative hyperoxygenation in prophylaxis of infections after liver transplantation.

METHODS

In this randomized controlled trial, patients undergoing liver transplantation were randomly assigned to either 28% or 80% fraction of inspired oxygen (FiO₂) for 6 postoperative hours. Infections occurring during 30-day post-transplant period were the primary outcome measure. Secondary outcome measures included 90-day mortality, 90-day severe morbidity, 30-day pulmonary complications, durations of hospital and intensive care unit stay, and 5-day postoperative bilirubin concentration, alanine and aspartate transaminase activity, and international normalized ratio (INR) (clinicatrials.gov NCT02857855).

RESULTS

A total of 193 patients were included and randomized to 28% (n = 99) and 80% (n = 94) FiO₂. With similar patient, operative, and donor characteristics in both groups, infections occurred in 34.0% (32/94) of patients assigned to 80% FiO₂ as compared to 23.2% (23/99) of patients assigned to 28% FiO₂ (p = 0.112). Patients randomized to 80% FiO₂ more frequently developed severe complications (p = 0.035), stayed longer in the intensive care unit (p = 0.033), and had higher bilirubin concentration over first 5 post-transplant days (p = 0.043). No significant differences were found regarding mortality, duration of hospital stay, pulmonary complications, and 5-day aspartate and alanine transaminase activity and INR.

CONCLUSIONS

Postoperative hyperoxygenation should not be used for prophylaxis of infections after liver transplantation due to the lack of efficacy.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02857855. Registered 7 July 2016.

Development of a Risk Classifier to Predict Tumor Recurrence and Lenvatinib Benefits in Hepatocellular Carcinoma After Liver Transplantation

BACKGROUND

Current selection tools were not precise enough to predict recurrence of hepatocellular carcinoma (HCC) and benefit of adjuvant lenvatinib for patients who received liver transplant (LT) for HCC. Thus, we aim at developing a risk classifier to predict recurrence of HCC and benefit of adjuvant Lenvatinib for those who underwent LT for HCC.

METHODS

Cox regression model was applied to selected predictors and created the final model in a training cohort of 287 patients who underwent LT for HCC, which was tested in an internal validation cohort of 72 patients by using C-statistic and net classification index (NRI) compared with the following HCC selection criteria: the Milan criteria, the Up-to-7 criteria, and the University of California, San Francisco criteria.

RESULTS

We built a Risk Classifier of South China Cohort (RCOSC) based on 4 variables: the maximum diameter plus number of viable tumors, alpha-fetoprotein, microvascular invasion, and highest alanine aminotransferase in 7 days after LT. In validation analyses, our RCOSC showed good predictive performance (C-statistic, 0.866; 95% confidence interval [CI], 0.833-0.899) and had better prognostic value than Milan criteria (NRI, 0.406; P < .001), University of California, San Francisco (NRI, 0.497; P < .001), and Up-to-7 (NRI, 0.527; P < .001). By applying the RCOSC, we were able to accurately categorize patients into high-risk and low-risk groups. Further survival analysis revealed that the patients in the high-risk group might have a better therapeutic response to preventive regimen of lenvatinib after LT for HCC (hazard ratio, 0.38; 95% CI, 0.161-0.871, P = .018).

CONCLUSIONS

Our RCOSC presented favorable predictive performance for HCC recurrence. It might be capable of sifting out patients who benefit from adjuvant therapy after LT for HCC, providing a reliable tool for precise clinical decision-making of patients with HCC with LT.

The role of extracellular traps in ischemia reperfusion injury

In response to strong signals, several types of immune cells release extracellular traps (ETs), which are web-like structures consisting of DNA decorated with various protein substances. This process is most commonly observed in neutrophils. Over the past two decades, ET formation has been recognized as a unique mechanism of host defense and pathogen destruction. However, the role of ETs in sterile inflammation has only been studied extensively in recent years. Ischemia reperfusion injury (IRI) is a type of sterile inflammatory injury. Several studies have reported that ETs have an important role in IRI in various organs. In this review, we describe the release of ETs by various types of immune cells and focus on the mechanism underlying the formation of neutrophil ETs (NETs). In addition, we summarize the role of ETs in IRI in different organs and their effects on tumors. Finally, we discuss the value of ETs as a potential therapeutic target for organ IRI and present possible challenges in conducting studies on IRI-related ETs as well as future research directions and prospects.

Mitochondria and Cancer Recurrence after Liver Transplantation—What Is the Benefit of Machine Perfusion?

Tumor recurrence after liver transplantation has been linked to multiple factors, including the recipient’s tumor burden, donor factors, and ischemia-reperfusion injury (IRI). The increasing number of livers accepted from extended criteria donors has forced the transplant community to push the development of dynamic perfusion strategies. The reason behind this progress is the urgent need to reduce the clinical consequences of IRI. Two concepts appear most beneficial and include either the avoidance of ischemia, e.g., the replacement of cold storage by machine perfusion, or secondly, an endischemic organ improvement through perfusion in the recipient center prior to implantation. While several concepts, including normothermic perfusion, were found to reduce recipient transaminase levels and early allograft dysfunction, hypothermic oxygenated perfusion also reduced IRI-associated post-transplant complications and costs. With the impact on mitochondrial injury and subsequent less IRI-inflammation, this endischemic perfusion was also found to reduce the recurrence of hepatocellular carcinoma after liver transplantation. Firstly, this article highlights the contributing factors to tumor recurrence, including the surgical and medical tissue trauma and underlying mechanisms of IRI-associated inflammation. Secondly, it focuses on the role of mitochondria and associated interventions to reduce cancer recurrence. Finally, the role of machine perfusion technology as a delivery tool and as an individual treatment is discussed together with the currently available clinical studies.

p21-activated kinase 4 inhibition protects against liver ischemia/reperfusion injury: Role of nuclear factor erythroid 2-related factor 2 phosphorylation

BACKGROUND AND AIMS

p21-activated kinase 4 (PAK4), an oncogenic protein, has emerged as a promising target for anticancer drug development. Its role in oxidative stress conditions, however, remains elusive. We investigated the effects of PAK4 signaling on hepatic ischemia/reperfusion (I/R) injury.

APPROACH AND RESULTS

Hepatocyte- and myeloid-specific Pak4 knockout (KO) mice and their littermate controls were subjected to a partial hepatic I/R (HIR) injury. We manipulated the catalytic activity of PAK4, either through genetic engineering (gene knockout, overexpression of wild-type [WT] or dominant-negative kinase) or pharmacological inhibitor, coupled with a readout of nuclear factor erythroid 2-related factor 2 (Nrf2) activity, to test the potential function of PAK4 on HIR injury. PAK4 expression was markedly up-regulated in liver during HIR injury in mice and humans. Deletion of PAK4 in hepatocytes, but not in myeloid cells, ameliorated liver damages, as demonstrated in the decrease in hepatocellular necrosis and inflammatory responses. Conversely, the forced expression of WT PAK4 aggravated the pathological changes. PAK4 directly phosphorylated Nrf2 at T369, and it led to its nuclear export and proteasomal degradation, all of which impaired antioxidant responses in hepatocytes. Nrf2 silencing in liver abolished the protective effects of PAK4 deficiency. A PAK4 inhibitor protected mice from HIR injury.

CONCLUSIONS

PAK4 phosphorylates Nrf2 and suppresses its transcriptional activity. Genetic or pharmacological suppression of PAK4 alleviates HIR injury. Thus, PAK4 inhibition may represent a promising intervention against I/R-induced liver injury.

One Shoot, Two Birds: Alleviating Inflammation Caused by Ischemia/Reperfusion Injury to Reduce the Recurrence of Hepatocellular Carcinoma

Inflammation is crucial to tumorigenesis and the development of metastasis. Hepatic ischemia/reperfusion injury (IRI) is an unresolved problem in liver resection and transplantation which often establishes and remodels the inflammatory microenvironment in liver. More and more experimental and clinical evidence unmasks the role of hepatic IRI and associated inflammation in promoting the recurrence of hepatocellular carcinoma (HCC). Meanwhile, approaches aimed at alleviating hepatic IRI, such as machine perfusion, regulating the gut-liver axis, and targeting key inflammatory components, have been proved to prevent HCC recurrence. This review article highlights the underlying mechanisms and promising therapeutic strategies to reduce tumor recurrence through alleviating inflammation induced by hepatic IRI.

The effect of the number of hepatic inflow occlusion times on the prognosis of ruptured hepatocellular carcinoma patients after hepatectomy

Background and aim

It has been previously reported that inflow occlusion does not affect postoperative outcomes in hepatocellular carcinoma patients. However, for patients with ruptured hepatocellular carcinoma(rHCC), the effect of hepatic inflow occlusion and the number of occlusion times on the prognosis is unknown.

Methods

203 patients with ruptured hepatocellular carcinoma were enrolled in this study. They were first divided into the non-hepatic inflow occlusion (non-HIO) group and the hepatic inflow occlusion (HIO) group. The Kaplan–Meier method was used to compare the recurrence-free survival and overall survival between the two groups. Patients in the HIO group were further divided into one-time HIO and two times HIO groups. KM method was also used to compare the two groups. Finally, independent risk factors affecting RFS and OS were determined by multivariate Cox regression analysis.

Result

In the non-HIO group, 1-,3- and 5-year OS rates were 67.0%, 41.0%, and 22.0%respectively, and RFS rates were 45.0%, 31.0%, and 20.0% respectively; In the one-HIO group, the 1-,3-, and 5-year OS rates were 55.1%, 32.1%, and 19.2% respectively, and RFS rates were 33.3%, 16.7%, and 7.7% respectively; In the two-HIO group, 1-,3-, and 5-year OS rates were 24.0%, 0.0%, and 0.0% respectively, and RFS rates were 8.0%, 0.0%, and 0.0% respectively. By Cox regression analysis, HIO was an independent risk factor for a poor prognosis in rHCC patients.

Conclusion

One time hepatic inflow occlusion did not affect postoperative OS, but negatively affected the RFS of rHCC patients; two times hepatic inflow occlusion negatively affected the postoperative OS and RFS in patients with rHCC.

Predicting recurrence of hepatocellular carcinoma after liver transplantation using a novel model that incorporates tumor and donor-related factors

Evidence suggests that liver graft quality impacts on posttransplant recurrence of hepatocellular carcinoma (HCC). As of today, selection criteria only use variables related to tumor characteristics. Within the Scientific Registry of Transplant Recipients, we identified patients with HCC who underwent liver transplantation between 2004 and 2016 (development cohort, n = 10 887). Based on tumor recurrence rates, we fitted a competing-risk regression incorporating tumor- and donor-related factors, and we developed a prognostic score. Results were validated both internally and externally in the Australia and New Zealand Liver Transplant Registry. Total tumor diameter (subhazard ratio [sub-HR] 1.52 [1.28-1.81]), alpha-feto protein (sub-HR 1.27 [1.23-1.32], recipient male gender (sub-HR 1.43 [1.18-1.74]), elevated donor body mass index (sub-HR 1.26 [1.01-1.58]), and shared graft allocation policy (sub-HR 1.20 [1.01-1.43]) were independently associated with tumor recurrence. We next developed the Darlica score (sub-HR 2.72 [2.41-3.08] P < 0.001) that allows identifying risky combinations between a given donor and a given recipient. Results were validated internally (n = 3 629) and externally in the Australia and New Zealand Liver Transplant Registry (n = 370). The current score is based on variables that are readily available at the time of graft offer. It allows identifying hazardous donor-recipient combinations in terms of risk of tumor recurrence and overall survival.

Methods of Attenuating Ischemia-Reperfusion Injury in Liver Transplantation for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most frequent indications for liver transplantation. However, the transplantation is ultimately associated with the occurrence of ischemia-reperfusion injury (IRI). It affects not only the function of the graft but also significantly worsens the oncological results. Various methods have been used so far to manage IRI. These include the non-invasive approach (pharmacotherapy) and more advanced options encompassing various types of liver conditioning and machine perfusion. Strategies aimed at shortening ischemic times and better organ allocation pathways are still under development as well. This article presents the mechanisms responsible for IRI, its impact on treatment outcomes, and strategies to mitigate it. An extensive review of the relevant literature using MEDLINE (PubMed) and Scopus databases until September 2020 was conducted. Only full-text articles written in English were included. The following search terms were used: “ischemia reperfusion injury”, “liver transplantation”, “hepatocellular carcinoma”, “preconditioning”, “machine perfusion”.

Glutathione S-transferase A2 promotes hepatocellular carcinoma recurrence after liver transplantation through modulating reactive oxygen species metabolism

Hepatocellular carcinoma (HCC) recurrence after liver transplantation remains a significant clinical problem. Ischemia-reperfusion injury (IRI) occurred inevitably at the early phase after liver transplantation (LT) spawns a significant risk of HCC recurrence. However, their linkage and IRI-derived risk factors for HCC recurrence remain exclusive. Understanding the mechanism of post-transplantation hepatic injury could provide new strategies to prevent the later event of HCC recurrence. We demonstrated that glutathione S-transferase A2 (GSTA2) expression was significantly associated with early phase hepatic and systemic injury and ROS level after liver transplantation. Early phase circulating GSTA2 (_EPCGSTA2) protein was a significant predictor of HCC recurrence and survival. Heterogeneous single nucleotide polymorphism at G335C of GSTA2 was significantly associated with poor survival of HCC recipients. Enhancement of GSTA2 could protect HCC cells against H₂O₂-induced cell death by compensating for the elevated ROS stress. We also demonstrated that GSTA2 played crucial roles in regulating the ROS-associated JNK and AKT signaling pathways and ROS metabolism in HCCs in responding to a dynamic ROS environment. Functionally, endogenous or exogenous upregulation of GSTA2 could promote HCC growth and invasion through activating the epithelial–mesenchymal-transition process. Targeted inhibition of GSTA2 could suppress HCC growth and metastasis. In conclusion, GSTA2 could be a novel prognostic and therapeutic target to combat HCC recurrence after liver transplantation.

Transplant Oncology in Primary and Metastatic Liver Tumors: Principles, Evidence, and Opportunities

Transplant oncology defines any application of transplant medicine and surgery aimed at improving cancer patients' survival and/or quality of life. In practice, liver transplantation for selected hepato-biliary cancers is the only solid organ transplant with demonstrated efficacy in curing cancer. Four are the proposed future contributions of transplant oncology in hepato-biliary cancer (4-e). (1) evolutionary approach to cancer care that includes liver transplantation; (2) elucidation of self and non-self recognition systems, by linking tumor and transplant immunology; (3) exploration of innovative endpoints both in clinical and experimental settings taking advantage from the access to the entire liver explant; (4) extension of surgical limitation in the multidisciplinary approach to hepato-biliary oncology. The aim of this review is to define the principles of transplant oncology that may be applied to hepato-biliary cancer treatment and research, attempting to balance current evidences with future opportunities.

Shorter Survival after Liver Pedicle Clamping in Patients Undergoing Liver Resection for Hepatocellular Carcinoma Revealed by a Systematic Review and Meta-Analysis

Simple Summary

Hepatocellular carcinoma (HCC) is the most prevalent tumor of the liver and represents the second most common cause of oncological-related deaths worldwide. Despite all progress made in the field, surgical resection or liver transplantation are, at the moment, the only curative therapies available. Liver resection, especially for large, central tumors, are at risk of important bleeding. Significative hemorrhage during HCC resections have been linked to an increased rate of post-operative complications and tumor recurrence. Therefore, hepatic pedicle clamping during surgery has been used in order to reduce the bleeding risks. However, this method induces ischemia/reperfusion injuries, which has also been associated with tumor recurrence. For this reason, we aimed to evaluate if pedicle clamping is indeed associated with tumor recurrence and shorter survival, by performing a systematic review of the literature and meta-analysis.

Abstract

Liver pedicle clamping minimizes surgical bleeding during hepatectomy. However, by inducing ischemia-reperfusion injury to the remnant liver, pedicle clamping may be associated with tumor recurrence in the regenerating liver. Hepatocellular carcinoma (HCC) having a high rate of recurrence, evidences demonstrating an eventual association with pedicle clamping is strongly needed. We did a systematic review of the literature until April 2020, looking at studies reporting the impact of liver pedicle clamping on long-term outcomes in patients undergoing liver resection for HCC. Primary and secondary outcomes were overall survival (OS) and disease-free survival, respectively. Results were obtained by random-effect meta-analysis and expressed as standardized mean difference (SMD). Eleven studies were included, accounting for 8087 patients. Results of seven studies were pooled in a meta-analysis. Findings indicated that, as compared to control patients who did not receive liver pedicle clamping, those who did had a significantly shorter OS (SMD = −0.172, 95%CI: −0.298 to −0.047, p = 0.007, I² = 76.8%) and higher tumor recurrence rates (odds ratio 1.36 1.01 to 1.83. p = 0.044, I² = 50.7%). This meta-analysis suggests that liver pedicle clamping may have a deleterious impact on long-term outcomes. An individual patient-data meta-analysis of randomized trials evaluating liver pedicle clamping is urgently needed.

Venous outflow congestion is related to poor recurrence-free survival of living donor liver transplantation recipients with hepatocellular carcinoma - a retrospective study

This study analyzed the impact of venous outflow congestion in the liver graft on hepatocellular carcinoma recurrence in liver transplantation recipients. Hepatocellular carcinoma patients who underwent living donor liver transplantation at Samsung Medical Center between 2007 and 2018 were included. The congested volume was calculated based on 2-week post-transplantation computed tomography. Recurrence-free survival and overall survival were analyzed using the multivariable Cox proportional hazard model including the degree of venous congestion. A total of 582 patients were included. There were 232 patients (39.9%) with certain degree of congestion volume. Kaplan-Meier survival analyses showed 1-, 5-, and 10-year recurrence-free survivals of 86.0%, 72.2%, and 70.7%, respectively, and overall survivals of 91.5%, 73.4%, and 68.9%, respectively. While congestion volume per 10 cm³ was a significant risk factor for recurrence-free survival (HR = 1.024, CI: 1.002-1.047, P = 0.034), there was no significant relationship with overall survival. (HR = 1.015, CI: 0.992-1.039, P = 0.213). Venous outflow congestion in the liver after living donor liver transplantation was related to the poor recurrence-free survival of hepatocellular carcinoma patients.

Preventing Tumour Recurrence after Liver Transplantation: The Role of Machine Perfusion

Tumour recurrence is currently a hot topic in liver transplantation. The basic mechanisms are increasingly discussed, and, for example, recurrence of hepatocellular carcinoma is often described in pre-injured donor livers, which frequently suffer from significant ischemia/reperfusion injury. This review article highlights the underlying mechanisms and describes the specific tissue milieu required to promote tumour recurrence after liver transplantation. We summarise the current literature in this field and show risk factors that contribute to a pro-tumour-recurrent environment. Finally, the potential role of new machine perfusion technology is discussed, including the most recent data, which demonstrate a protective effect of hypothermic oxygenated perfusion before liver transplantation.

Induction of in vitro Metabolic Zonation in Primary Hepatocytes Requires Both Near-Physiological Oxygen Concentration and Flux

Pre-clinical drug screening is an important step in assessing the metabolic effects and hepatic toxicity of new pharmaceutical compounds. However, due to the complexity of the liver microarchitecture, simplified in vitro models do not adequately reflect in vivo situations. Especially spatial heterogeneity, known as metabolic zonation, is often lost due to limitations introduced by typical culture conditions. By culturing primary rat hepatocytes in varied ambient oxygen levels on either gas-permeable or non-permeable culture plates, we highlight the importance of biomimetic oxygen supply for the targeted induction of zonation-like phenotypes. Resulting cellular profiles illustrate the effect of pericellular oxygen concentration and consumption rates on hepatic functionality in terms of zone-specific metabolism and β-catenin signaling. We show that modulation of ambient oxygen tension can partially induce metabolic zonation in vitro when considering high supply rates, leading to in vivo-like drug metabolism. However, when oxygen supply is limited, similar modulation instead triggers an ischemic reprogramming, resembling metabolic profiles of hepatocellular carcinoma and increasing susceptibility toward drug-induced injury. Application of this knowledge will allow for the development of more accurate drug screening models to better identify adverse effects in hepatic drug metabolism.

Does graft hemodynamics affect the risk of hepatocellular carcinoma recurrence after liver transplantation?

Although experimental studies have reported that hepatic ischemia-reperfusion injury promotes tumor growth and metastases, the impact of graft hemodynamics on the recurrence of hepatocellular carcinoma (HCC) after liver transplantation (LT) is unclear. To investigate the association between graft hemodynamics and HCC recurrence after LT, we conducted a retrospective analysis of 279 patients who underwent LT for HCC. Graft hemodynamics including portal vein flow (PVF), hepatic artery flow (HAF), and total hepatic flow (THF) was analyzed as a predictor of HCC recurrence, using competing risk regression analyses. The cutoff values of PVF, HAF, and THF were set at the lower quartile of distribution. A cumulative recurrence curve demonstrated that low THF (<1511 mL/min, P = .005) was significantly associated with increased recurrence, whereas neither low PVF (<1230 mL/min, P = .150) nor low HAF (<164 mL/min, P = .110) was significant. On multivariate analysis, outside Milan criteria (sub-hazard ratio [SHR] = 3.742; P < .001), microvascular invasion (SHR = 3.698; P < .001), and low THF (SHR = 2.359; P = .010) were independently associated with increased HCC recurrence. In conclusion, our findings suggest that graft hemodynamics may play an important role in HCC recurrence after LT.

Identification of a novel gene signature for the prediction of recurrence in HCC patients by machine learning of genome-wide databases

Hepatocellular carcinoma (HCC) is a common malignant tumor in China. In the present study, we aimed to construct and verify a prediction model of recurrence in HCC patients using databases (TCGA, AMC and Inserm) and machine learning methods and obtain the gene signature that could predict early relapse of HCC. Statistical methods, such as feature selection, survival analysis and Chi-Square test in R software, were used to analyze and select mutant genes related to disease free survival (DFS), race and vascular invasion. In addition, whole-exome sequencing was performed on 10 HCC patients recruited from our center, and the sequencing results were compared with the databases. Using the databases and machine learning methods, the prediction model of recurrence was constructed and optimized, and the selected mutant genes were verified in the test group. The accuracy of prediction was 74.19%. Moreover, these 10 patients from our center were used to verify these mutant genes and the prediction model, and a success rate of 80% was achieved. Collectively, we discovered recurrence-related genes and established recurrence prediction model of recurrence for HCC patients, which could provide significant guidance for clinical prediction of recurrence.

Premetastatic niches, exosomes and circulating tumor cells: Early mechanisms of tumor dissemination and the relation to surgery

The physiological stress response to surgery promotes wound healing and functional recovery and includes the activation of neural, inflammatory and proangiogenic signaling pathways. Paradoxically, the same pathways also promote metastatic spread and growth of residual cancer. Human and animal studies show that cancer surgery can increase survival, migration and proliferation of residual tumor cells. To secure the survival and growth of disseminated tumor cells, the formation of premetastatic niches in target organs involves a complex interplay between microenvironment, immune system, circulating tumor cells, as well as chemical mediators and exosomes secreted by the primary tumor. This review describes the current understanding of the early mechanisms of dissemination, as well as how surgery may facilitate disease progression.

Ischemia reperfusion injury promotes recurrence of hepatocellular carcinoma in fatty liver via ALOX12-12HETE-GPR31 signaling axis

BACKGROUND

Ischemia reperfusion injury (IRI) has been shown to increase the risk of tumor recurrence after liver surgery. Also, nonalcoholic fatty liver disease (NAFLD) is associated with increased HCC recurrence. ALOX12-12-HETE pathway is activated both in liver IRI and NASH. Also, ALOX12-12-HETE has been shown to mediate tumorigenesis and progression. Therefore, our study aims to investigate whether the ALOX12-12-HETE-GPR31 pathway involved in IRI induced HCC recurrence in NAFLD.

METHODS

HCC mouse model was used to mimic the HCC recurrence in NAFLD. Western Blot, qPCR, Elisa and Immunofluorescence analysis were conducted to evaluate the changes of multiple signaling pathways during HCC recurrence, including ALOX12-12-HETE axis, EMT, MMPs and PI3K/AKT/NF-κB signaling pathway. We also measured the expression and functional changes of GPR31 by siRNA.

RESULTS

ALOX12-12-HETE pathway was activated in liver IRI and its activation was further enhanced in NAFLD, which induced more severe HCC recurrence in fatty livers than normal livers. Inhibition of ALOX12-12-HETE by ML355 reduced the HCC recurrence in fatty livers. In vitro studies showed that 12-HETE increased the expression of GPR31 and induced epithelial-mesenchymal transition (EMT) and matrix metalloprotein (MMPs) by activating PI3K/AKT/NF-κB pathway. Furthermore, knockdown of GPR31 in cancer cells inhibited the HCC recurrence in NAFLD.

CONCLUSIONS

ALOX12-12-HETE-GPR31 played an important role in HCC recurrence and might be a potential therapeutic target to reduce HCC recurrence after surgery in fatty livers.

The impact of short-term machine perfusion on the risk of cancer recurrence after rat liver transplantation with donors after circulatory death

Hypothermic and normothermic ex vivo liver perfusions promote organ recovery after donation after circulatory death (DCD). We tested whether these perfusions can reduce the risk of hepatocellular carcinoma (HCC) recurrence in a 1h-DCD syngeneic transplantation model, using Fischer F344 rats. DCD grafts were machine perfused for 2h with hypothermic perfusion (HOPE) or normothermic perfusion (NORMO), and transplanted. After reperfusion, we injected HCC cells into the vena porta. On day 28 after transplantation, we assessed tumour volumes by MRI. Control rats included transplantations with Fresh and non-perfused DCD livers. We observed apoptotic-necrotic hepatocyte foci in all DCD grafts, which were more visible than in the Fresh liver grafts. Normothermic perfusion allowed a faster post-transplant recovery, with lower day 1 levels of transaminases compared with the other DCD. Overall, survival was similar in all four groups and all animals developed HCCs. Total tumor volume was lower in the Fresh liver recipients compared to the DCD and DCD+HOPE recipients. Volumes in DCD+NORMO recipients were not significantly different from those in the Fresh group. This experiment confirms that ischemia/reperfusion injury promotes HCC cell engraftment/growth after DCD liver transplantation. Using the present extreme 1h ischemia model, both hypothermic and normothermic perfusions were not effective in reducing this risk.

Impact of Body Composition on the Risk of Hepatocellular Carcinoma Recurrence After Liver Transplantation

BACKGROUND

Body composition parameters are reported to influence the risk of hepatocellular carcinoma (HCC) recurrence after liver resection, yet data on patients undergoing liver transplantation are scarce. The aim of this study was to evaluate the impact of the amount of abdominal adipose tissue and skeletal muscles on the risk of HCC recurrence after liver transplantation.

METHODS

This was a retrospective observational study performed on 77 HCC patients after liver transplantation. Subcutaneous fat area (SFA), visceral fat area, psoas muscle area and total skeletal muscle area were assessed on computed tomography on the level of L3 vertebra and divided by square meters of patient height. The primary outcome measure was five-year recurrence-free survival.

RESULTS

Recurrence-free survival in the entire cohort was 95.7%, 90.8%, and 86.5% after one, three, and five years post-transplantation, respectively. SFA was significantly associated with the risk of HCC recurrence (p = 0.013), whereas no significant effects were found for visceral fat and skeletal muscle indices. The optimal cut-off for SFA for prediction of recurrence was 71.5 cm²/m². Patients with SFA < 71.5 cm²/m² and ≥71.5 cm²/m² exhibited five-year recurrence-free survival of 96.0% and 55.4%, respectively (p = 0.001).

CONCLUSIONS

Excessive amount of subcutaneous adipose tissue is a risk factor for HCC recurrence after liver transplantation and may be considered in patient selection process.

Extremes of Liver Transplantation for Hepatocellular Carcinoma

The aim of this retrospective observational study was to evaluate outcomes of patients with extremely advanced hepatocellular carcinoma (HCC) after liver transplantation. A total of 285 HCC patients after liver transplantation were screened for eligibility based on either intrahepatic dissemination (≥10 tumors) or macrovascular invasion. Tumor recurrence was the primary end-point. The study cohort comprised 26 patients. Median recurrence-free survival was 23.2 months with hepatitis B virus (HBV) infection (p = 0.038), higher AFP model score (p = 0.001), prolonged graft ischemia (p = 0.004), and younger donor age (p = 0.016) being significant risk factors. Median recurrence-free survival of HBV-negative and HBV-positive patients was 29.8 and 9.3 months, respectively (p = 0.053). In patients with macrovascular invasion, recurrence-free survival at 3 years was 46.3% with no specific predictors. Tumor size (p = 0.044), higher AFP model score (p = 0.019), prolonged graft ischemia (p = 0.016), and younger donor age (p = 0.041) were significant risk factors in patients with intrahepatic dissemination. Superior 3-year outcomes were observed in patients with intrahepatic dissemination and tumor size <3.5 cm (83.3%, p = 0.027) and HBV-negative patients with ischemia <9.7 h (85.7%, p = 0.028). In conclusion, patients with extremely advanced HCCs are remarkably heterogeneous with respect to their profile of tumor recurrence risk. This heterogeneity is largely driven by factors other than standard predictors of post-transplant HCC recurrence.

Sphingosine kinase 1 knockout alleviates hepatic ischemia/reperfusion injury by attenuating inflammation and oxidative stress in mice

BACKGROUND

Hepatic ischemia/reperfusion (I/R) injury remains a significant problem in clinical practice. Sphingosine kinase 1 (SphK1) phosphorylates sphingosine to sphingosine-1-phosphate (S1P) which participates in multiple bioactive processes. However, little is known about the role of SphK1 in hepatic I/R injury. This study aimed to investigate the effect of SphK1 knockout on liver I/R injury and to explore underlying mechanisms.

METHODS

SphK1 knockout and wild type mice were subjected to 70% partial hepatic I/R. Serum alanine aminotransferase was determined to indicate the degree of liver damage. Hematoxylin-eosin staining and TUNEL assay were used to assess histological changes and hepatocellular apoptosis, respectively. Immunohistochemistry was performed to detect the expression and translocation of phosphorylated p65 and signal transducer and activator of transcription 3 (STAT3). Western blotting was used to determine the expression of S1P receptor 1 (S1PR1), phosphorylated p65 and STAT3. Real-time PCR was used to demonstrate the changes of proinflammatory cytokines. Oxidative stress markers were also determined through biochemical assays.

RESULTS

SphK1 knockout significantly ameliorated I/R-induced liver damage, mitigated liver tissue necrosis and apoptosis compared with wild type control. I/R associated inflammation was alleviated in SphK1 knockout mice as demonstrated by attenuated expression of S1PR1 and reduced phosphorylation of nuclear factor kappa B p65 and STAT3. The proinflammatory cytokines interleukin-1β, interleukin-6 and tumor necrosis factor-α were also inhibited by SphK1 genetic deletion. The oxidative stress markers were lower in SphK1 knockout mice after I/R injury than wild type mice.

CONCLUSIONS

Knockout of SphK1 significantly alleviated damage after hepatic I/R injury, possibly through inhibiting inflammation and oxidative stress. SphK1 may be a novel and potent target in clinical practice in I/R-related liver injury.