A prospective randomized study in 100 consecutive patients undergoing major liver resection with versus without ischemic preconditioning

Predicting mitophagy-related genes and unveiling liver endothelial cell heterogeneity in hepatic ischemia-reperfusion injury

Background

Hepatic Ischemia-Reperfusion Injury (HIRI) is a major complication in liver transplants and surgeries, significantly affecting postoperative outcomes. The role of mitophagy, essential for removing dysfunctional mitochondria and maintaining cellular balance, remains unclear in HIRI.

Methods

To unravel the role of mitophagy-related genes (MRGs) in HIRI, we assembled a comprehensive dataset comprising 44 HIRI samples alongside 44 normal control samples from the Gene Expression Omnibus (GEO) database for this analysis. Using Random Forests and Support Vector Machines - Recursive Feature Elimination (SVM-RFE), we pinpointed eight pivotal genes and developed a logistic regression model based on these findings. Further, we employed consensus cluster analysis for classifying HIRI patients according to their MRG expression profiles and conducted weighted gene co-expression network analysis (WGCNA) to identify clusters of genes that exhibit high correlation within different modules. Additionally, we conducted single-cell RNA sequencing data analysis to explore insights into the behavior of MRGs within the HIRI.

Results

We identified eight key genes (FUNDC1, VDAC1, MFN2, PINK1, CSNK2A2, ULK1, UBC, MAP1LC3B) with distinct expressions between HIRI and controls, confirmed by PCR validation. Our diagnostic model, based on these genes, accurately predicted HIRI outcomes. Analysis revealed a strong positive correlation of these genes with monocytic lineage and a negative correlation with B and T cells. HIRI patients were divided into three subclusters based on MRG profiles, with WGCNA uncovering highly correlated gene modules. Single-cell analysis identified two types of endothelial cells with different MRG scores, indicating their varied roles in HIRI.

Conclusions

Our study highlights the critical role of MRGs in HIRI and the heterogeneity of endothelial cells. We identified the macrophage migration inhibitory factor (MIF) and cGAS-STING (GAS) pathways as regulators of mitophagy's impact on HIRI. These findings advance our understanding of mitophagy in HIRI and set the stage for future research and therapeutic developments.

Liver ischemia-reperfusion injury: From trigger loading to shot firing

An ischemia-reperfusion injury (IRI) results from a prolonged ischemic insult followed by the restoration of blood perfusion, being a common cause of morbidity and mortality, especially in liver transplantation. At the maximum of the potential damage, IRI is characterized by 2 main phases. The first is the ischemic phase, where the hypoxia and vascular stasis induces cell damage and the accumulation of damage-associated molecular patterns and cytokines. The second is the reperfusion phase, where the local sterile inflammatory response driven by innate immunity leads to a massive cell death and impaired liver functionality. The ischemic time becomes crucial in patients with underlying pathophysiological conditions. It is possible to compare this process to a shooting gun, where the loading trigger is the ischemia period and the firing shot is the reperfusion phase. In this optic, this article aims at reviewing the main ischemic events following the phases of the surgical timeline, considering the consequent reperfusion damage.

PREVENTION OF PATHOLOGICAL EFFECT OF ISCHEMIA-REPERFUSION IN LIVER RESECTION BY SEVOFLURANE PRECONDITIONING

BACKGROUND

The intermittent Pringle maneuver remains the major technique for controlling hemorrhage during liver surgery. Nevertheless, this procedure involves a risk of triggering a cascade of pathological changes resulting in the ischemia-reperfusion injury (I/R) effect. The pharmacological prevention of this I/R injury represents a promising approach. The aim of the study was to compare the effects of pharmacological preconditioning with sevoflurane and propofol-based intravenous anesthesia on the postoperative function of the liver as the primary end-point.

MATERIALS AND METHODS

A prospective cohort study includes the analysis of the data of 73 patients who underwent liver surgery. In the study group (n = 41), preconditioning with sevoflurane inhalation was provided 30 minutes prior to liver resection. In the control group (n = 32), sevoflurane preconditioning was not provided. The primary endpoints were blood lactate concentration shortly after the surgery and one day later; alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities on postoperative Days 1, 3, and 5 as markers of hepatocyte damage.

RESULTS

On postoperative Day 1, in patients of the study group, lactate decreased to preoperative levels, while in the control group, lactate content increased as compared to both preoperative levels and the levels immediately after liver resection. A significant difference in AST activity levels between the groups was registered on Day 5, although this difference was not clinically relevant. The decrease in the prothrombin index in the study group on Day 3 was superior to that in the control group. The multiple regression analysis demonstrated a moderate positive association between the number of resected liver segments and the markers of the functional state of the liver in the study group while in the control group, such association was not significant.

CONCLUSION

The protective effect of sevoflurane on the postoperative function of the liver is manifested by the lower level of blood lactate and the stable level of transaminase activity.

How to Preserve Steatotic Liver Grafts for Transplantation

Liver allograft steatosis is a significant risk factor for postoperative graft dysfunction and has been associated with inferior patient and graft survival, particularly in the case of moderate or severe macrovesicular steatosis. In recent years, the increasing incidence of obesity and fatty liver disease in the population has led to a higher proportion of steatotic liver grafts being used for transplantation, making the optimization of their preservation an urgent necessity. This review discusses the mechanisms behind the increased susceptibility of fatty livers to ischemia-reperfusion injury and provides an overview of the available strategies to improve their utilization for transplantation, with a focus on preclinical and clinical evidence supporting donor interventions, novel preservation solutions, and machine perfusion techniques.

Impacts of ischemic preconditioning in liver resection: systematic review with meta-analysis

OBJECTIVE

To assess the beneficial effects of ischemic preconditioning (IPC) in liver resection and evaluate its applicability in clinical practice.

SUMMARY BACKGROUND DATA

Liver surgeries are usually associated with intentional transient ischemia for hemostatic control. IPC is a surgical step that intends to reduce the effects of ischemia-reperfusion; however, there is no strong evidence about the real impact of the IPC, and it is necessary to effectively clarify what its effects are.

METHODS

Randomized clinical trials were selected, comparing IPC with no preconditioning in patients undergoing liver resection. Data were extracted by three independent researchers according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, Supplemental Digital Content 1, http://links.lww.com/JS9/A79 . Several outcomes were evaluated, including postoperative peaks of transaminases and bilirubin, mortality, length of hospital stay, length of stay in the ICU, bleeding, and transfusion of blood products, among others. Bias risks were assessed using the Cochrane collaboration tool.

RESULTS

Seventeen articles were selected, with a total of 1052 patients. IPC did not change the surgical time of the liver resections while these patients bled less (Mean Difference: -49.97 ml; 95% CI: -86.32 to -13.6; I2 : 64%), needed less blood products [relative risk (RR): 0.71; 95% CI: 0.53-0.96; I2 =0%], and had a lower risk of postoperative ascites (RR: 0.40; 95% CI: 0.17-0.93; I2 =0%). The other outcomes had no statistical differences or could not have their meta-analyses conducted due to high heterogeneity.

CONCLUSIONS

IPC is applicable in clinical practice, and it has some beneficial effects. However, there is not enough evidence to encourage its routine use.

Physics-based tissue simulator to model multicellular systems: A study of liver regeneration and hepatocellular carcinoma recurrence

We present a multiagent-based model that captures the interactions between different types of cells with their microenvironment, and enables the analysis of the emergent global behavior during tissue regeneration and tumor development. Using this model, we are able to reproduce the temporal dynamics of regular healthy cells and cancer cells, as well as the evolution of their three-dimensional spatial distributions. By tuning the system with the characteristics of the individual patients, our model reproduces a variety of spatial patterns of tissue regeneration and tumor growth, resembling those found in clinical imaging or biopsies. In order to calibrate and validate our model we study the process of liver regeneration after surgical hepatectomy in different degrees. In the clinical context, our model is able to predict the recurrence of a hepatocellular carcinoma after a 70% partial hepatectomy. The outcomes of our simulations are in agreement with experimental and clinical observations. By fitting the model parameters to specific patient factors, it might well become a useful platform for hypotheses testing in treatments protocols.

Spatial transcriptomics analysis of zone-dependent hepatic ischemia-reperfusion injury murine model

Hepatic ischemia-reperfusion (I/R) injury is a common complication in liver transplantation. The connection between I/R-induced injury response and liver heterogeneity has yet to be fully understood. In this study, we converge histopathological examination with spatial transcriptomics to dissect I/R injury patterns and their associated molecular changes, which reveal that the pericentral zones are most sensitive to I/R injury in terms of histology, transcriptomic changes, and cell type dynamics. Bioinformatic analysis of I/R injury-related pathways predicts that celastrol can protect against liver I/R injury by inducing ischemic pre-conditioning, which is experimentally validated. Mechanistically, celastrol likely implements its protective effect against I/R injury by activating HIF1α signaling and represents a potential strategy for resolving liver I/R.

Experimental and Clinical Aspects of Sevoflurane Preconditioning and Postconditioning to Alleviate Hepatic Ischemia-Reperfusion Injury: A Scoping Review

Ischemia-reperfusion injury (IRI) is an inflammatory process inherent in organ transplantation procedures. It is associated with tissue damage and, depending on its intensity, can impact early graft function. In liver transplantation (LT), strategies to alleviate IRI are essential in order to increase the use of extended criteria donor (ECD) grafts, which are more susceptible to IRI, as well as to improve postoperative graft and patient outcomes. Sevoflurane, a commonly used volatile anesthetic, has been shown to reduce IRI. This scoping review aims to give a comprehensive overview of the existing experimental and clinical data regarding the potential benefits of sevoflurane for hepatic IRI (HIRI) and to identify any gaps in knowledge to guide further research. We searched Medline and Embase for relevant articles. A total of 380 articles were identified, 45 of which were included in this review. In most experimental studies, the use of sevoflurane was associated with a significant decrease in biomarkers of acute liver damage and oxidative stress. Administration of sevoflurane before hepatic ischemia (preconditioning) or after reperfusion (postconditioning) appears to be protective. However, in the clinical setting, results are conflicting. While some studies showed a reduction of postoperative markers of liver injury, the benefit of sevoflurane on clinical outcomes and graft survival remains unclear. Further prospective clinical trials remain necessary to assess the clinical relevance of the use of sevoflurane as a protective factor against HIRI.

Surgical management in hepatoblastoma: points to take

Hepatoblastoma is the most common primary malignant paediatric liver tumour and surgery remains the cornerstone of its management. The aim of this article is to present the principles of surgical treatment of hepatoblastoma. All aspects of surgery in hepatoblastoma are discussed, from biopsy, through conventional and laparoscopic liver resections, to extreme resection with adjacent structures, staged hepatectomy and transplantation.

Protective Efficiency Comparison of Direct and Remote Ischemic Preconditioning on Ischemia Reperfusion Injury of the Liver in Patients Undergoing Partial Hepatectomy

Objective

Ischemia reperfusion injury greatly damages liver function and deteriorates the prognosis of patients undergoing partial hepatectomy. This study is to compare the protective efficiency of direct and remote ischemic preconditioning (DIPC and RIPC) on ischemia reperfusion injury of the liver in patients undergoing partial hepatectomy.

Methods

90 patients scheduled for partial hepatectomy were enrolled and randomly divided into control (n = 30), DIPC (n = 30), and RIPC (n = 30) groups. Baseline and surgery characteristics were collected, and ischemic preconditioning methods were carried out. Intraoperative hemodynamics, liver function and liver reserve capacity, oxidative stress, and inflammatory responses were measured, and the incidence of postoperative adverse reactions was calculated finally.

Results

10 patients were excluded from the study, and finally, the eligible patients in three groups were 27, 28, and 25, separately. No significant differences were observed in baseline and surgery characteristics among the three groups. SBP and DBP were significantly higher after hepatic portal vein occlusion while they were significantly lower after surgery in the DIPC and RIPC groups compared with that in the control group, SBP and DBP were of great fluctuation at different time points in the control group while they showed much more stabilization in the DIPC and RIPC groups. ALT, AST, and TBIL were significantly decreased on days 1, 3, and 5 after surgery, and ICG R15 was significantly decreased while ICG K value and EHBF were significantly increased on day 1 after surgery in the DIPC and RIPC groups compared with that in the control group. Moreover, antioxidant enzyme SOD was increased, and inflammatory factors TNF-α and IL-1β were decreased 24 hours after surgery in the DIPC and RIPC groups compared with that in the control group. DIPC and RIPC also decreased hospital stays and the incidence of nausea, vomiting, and hypertension.

Conclusion

DIPC and RIPC both alleviated ischemia reperfusion injury of the liver and reduced perioperative complications with similar protective efficiency in patients undergoing partial hepatectomy.

The role of laparoscopic surgery in the surgical management of recurrent liver malignancies: A systematic review and meta-analysis

Objective

To evaluate the efficiency of laparoscopic surgery in treating recurrent liver tumors vs. conventional open surgery.

Methods

Database searching was conducted in PubMed, the Cochrane Library and EMBASE. Rev Man 5.3 software and Stata 13.0 software were applied in statistical analyses.

Results

A total of fourteen studies were finally included with 1,284 patients receiving LRH and 2,254 with ORH. LRH was associated with less intraoperative hemorrhage, a higher R0 resection rate, a lower incidence of Pringle Maneuver, a lower incidence of postoperative morbidities, a better overall survival and an enhanced postoperative recovery vs. ORH. Patients receiving LRH shared similar operative time, tumor number and disease-free survival as those with ORH. However, tumor size was relatively larger in patients receiving ORH and major hepatectomy, anatomic hepatectomy were rarely performed in patients with LRH. Additional analyses between LRH and laparoscopic primary hepatectomy revealed less intraoperative blood loss in patients with LRH.

Conclusion

LRH is safe and feasible with more favorable peri-operative outcomes and faster postoperative recovery. However, it is only applicable for some highly-selected cases not requiring complex surgical procedures. Future larger well-designed studies are expected for further validation.

Incidence and risk factors for anastomotic bile leakage in hepatic resection with bilioenteric reconstruction - A international multicenter study

BACKGROUND

Anastomotic leak (AL) after bilioenteric reconstruction (BR) is a feared complication after bile duct resection, especially in combination with liver resection. Literature on surgical outcome is sparse. This study aimed to determine the incidence and risk factors for AL after combined liver and bile duct resection with a focus on operative or endoscopic reinterventions.

METHODS

Data from consecutive patients who underwent liver resection and BR between 2004 and 2018 in 11 academic institutions in Europe were collected from prospectively maintained databases.

RESULTS

Within 921 patients, AL rate was 5.4% with a 30d mortality of 9.6%. Pringle maneuver (p<0.001),postoperative external biliary (p=0.007) and abdominal drainage (p<0.001) were risk factors for clinically relevant AL. Preoperative biliary drainage (p<0.001) was not associated with a higher rate of AL. AL was more frequent in stented patients (76.5%) compared to PTCD (17.6%) or PTCD+stent (5.9%,p=0.017). AL correlated with increased incidence of postoperative liver failure (p=0.036), cholangitis, hemorrhage and sepsis (all p<0.001).

CONCLUSION

This multicenter data provides the largest series to date of LR with BR and could help in the management of these patients which are often challenging and hampering the patients' postoperative course negatively.

Metabolic Rewiring of Kynurenine Pathway during Hepatic Ischemia-Reperfusion Injury Exacerbates Liver Damage by Impairing NAD Homeostasis

Hepatic ischemia-reperfusion (IR) injury remains a common issue lacking effective strategy and validated pharmacological targets. Here, using an unbiased metabolomics screen, this study finds that following murine hepatic IR, liver 3-hydroxyanthranilic acid (3-HAA) and quinolinic acid (QA) decline while kynurenine and kynurenic acid (KYNA) increase. Kynurenine aminotransferases 2, functioning at the key branching point of the kynurenine pathway (KP), is markedly upregulated in hepatocytes during ischemia, shifting the kynurenine metabolic route from 3-HAA and QA to KYNA synthesis. Defects in QA synthesis impair de novo nicotinamide adenine dinucleotide (NAD) biosynthesis, rendering the hepatocytes relying on the salvage pathway for maintenance of NAD and cellular antioxidant defense. Blocking the salvage pathway following IR by the nicotinamide phosphoribosyltransferase inhibitor FK866 exacerbates liver oxidative damage and enhanced IR susceptibility, which can be rescued by the lipid peroxidation inhibitor Liproxstatin-1. Notably, nicotinamide mononucleotide administration once following IR effectively boosts NAD and attenuated IR-induced oxidative stress, inflammation, and cell death in the murine model. Collectively, the findings reveal that metabolic rewiring of the KP partitions it away from NAD synthesis in hepatic IR pathophysiology, and provide proof of concept that NAD augmentation is a promising therapeutic measure for IR-induced liver injury.

Does ALT Correlate with Survival After Liver Resection for Colorectal Liver Metastases?

Background

The pringle manoeuvre is commonly used during hepatectomy, which may cause ischaemia-reperfusion injury and transient liver dysfunction. Post-operative liver transaminases are often used to assess ischaemia-reperfusion injury, although there is conflicting evidence on survival outcomes. The primary aim was to assess post-operative alanine aminotransferase (ALT) with survival outcomes. Secondary aims were to assess ALT level with the length of stay and overall complications.

Methods

Post-operative day 2 ALT levels of five times the upper limit of normal (i.e. 280 U/L) were considered as clinically significant transaminitis. Kaplan-Meier survival curves were studied using log-rank analysis to identify the predictors of overall survival (OS) and recurrence-free survival (RFS).

Results

Out of 752 patients who underwent hepatectomy, 527 (70.1%) patients had low ALT (<280 U/L) and 225 (29.9%) patients had high ALT on day 2 post-op. Post-operative ALT did not affect OS (P = 0.883) or RFS (P = 0.063). Factors associated with a worse OS and RFS on multivariate analysis were pre-operative chemotherapy, number of tumours and largest tumour size (>4 cm). A high post-operative ALT was not associated with the increased length of stay or more complications.

Conclusions

Post-operative ALT does not affect survival outcomes post-hepatectomy for colorectal liver metastases.

Development and validation of a risk nomogram for postoperative acute kidney injury in older patients undergoing liver resection: a pilot study

BACKGROUND

Postoperative acute kidney injury (AKI) is associated with poor clinical outcomes. Early identification of high-risk patients of developing postoperative AKI can optimize perioperative renal management and facilitate patient survival. The present study aims to develop and validate a nomogram to predict postoperative AKI after liver resection in older patients.

METHODS

A retrospective observational study was conducted involving data from 843 older patients scheduled for liver resection at a single tertiary high caseload general hospital between 2012 and 2019. The data were randomly divided into training (70%, n = 599) and validation (30%, n = 244) datasets. The training cohort was used to construct a predictive nomogram for postoperative AKI with the logistic regression model which was confirmed by a validation cohort. The model was evaluated by receiver operating characteristic (ROC) curve, calibration plot, and decision curve analysis in the validation cohort. A summary risk score was also constructed for identifying postoperative AKI patients.

RESULTS

Postoperative AKI occurred in 155 (18.4%) patients and was highly associated with in-hospital mortality (5.2% vs. 0.7%, P <  0.001). The six predictors selected and assembled into the nomogram included age, preexisting chronic kidney disease (CKD), non-steroidal anti-inflammatory drugs (NSAIDs) usage, intraoperative hepatic inflow occlusion, blood loss, and transfusion. The predictive nomogram performed well in terms of discrimination with area under ROC curve (AUC) in training (0.73, 95% confidence interval (CI): 0.68-0.78) and validation (0.71, 95% CI: 0.63-0.80) datasets. The nomogram was well-calibrated with the Hosmer-Lemeshow chi-square value of 9.68 (P = 0.47). Decision curve analysis demonstrated a significant clinical benefit. The summary risk score calculated as the sum of points from the six variables (one point for each variable) performed as well as the nomogram in identifying the risk of AKI (AUC 0.71, 95% CI: 0.66-0.76).

CONCLUSION

This nomogram and summary risk score accurately predicted postoperative AKI using six clinically accessible variables, with potential application in facilitating the optimized perioperative renal management in older patients undergoing liver resection.

TRIAL REGISTRATION

NCT04922866 , retrospectively registered on clinicaltrials.gov on June 11, 2021.

Liver regeneration biology: Implications for liver tumour therapies

The liver has remarkable regenerative potential, with the capacity to regenerate after 75% hepatectomy in humans and up to 90% hepatectomy in some rodent models, enabling it to meet the challenge of diverse injury types, including physical trauma, infection, inflammatory processes, direct toxicity, and immunological insults. Current understanding of liver regeneration is based largely on animal research, historically in large animals, and more recently in rodents and zebrafish, which provide powerful genetic manipulation experimental tools. Whilst immensely valuable, these models have limitations in extrapolation to the human situation. In vitro models have evolved from 2-dimensional culture to complex 3 dimensional organoids, but also have shortcomings in replicating the complex hepatic micro-anatomical and physiological milieu. The process of liver regeneration is only partially understood and characterized by layers of complexity. Liver regeneration is triggered and controlled by a multitude of mitogens acting in autocrine, paracrine, and endocrine ways, with much redundancy and cross-talk between biochemical pathways. The regenerative response is variable, involving both hypertrophy and true proliferative hyperplasia, which is itself variable, including both cellular phenotypic fidelity and cellular trans-differentiation, according to the type of injury. Complex interactions occur between parenchymal and non-parenchymal cells, and regeneration is affected by the status of the liver parenchyma, with differences between healthy and diseased liver. Finally, the process of termination of liver regeneration is even less well understood than its triggers. The complexity of liver regeneration biology combined with limited understanding has restricted specific clinical interventions to enhance liver regeneration. Moreover, manipulating the fundamental biochemical pathways involved would require cautious assessment, for fear of unintended consequences. Nevertheless, current knowledge provides guiding principles for strategies to optimise liver regeneration potential.

The hepatoprotective effect from ischemia-reperfusion injury of remote ischemic preconditioning in the liver related surgery: a meta-analysis

BACKGROUND

This study aimed to assess the hepatoprotective effect of remote ischemic preconditioning (RIPC) in the liver related surgery.

METHODS

Published articles in PubMed, Embase and Cochrane clinical trial databases were searched from the inception to May 2021. Randomized control trials (RCTs) comparing the RIPC with control or other conditionings were included for analysis. The postoperative liver synthetic function was used as the primary outcome.

RESULTS

A total of six RCTs were included the present meta-analysis. There were 216 patients underwent RIPC and 212 patients in the control group. The RIPC group had a significantly lower level of postoperative alanine transaminase and aspartate transaminase (p<0.001). The postoperative bilirubin level was also significant lower in the RIPC group than the control group (MD = -9.0, 95%CI, -13.94 to -4.03; p<0.001). ICG clearance was reduced in controls versus RIPC (p<0.001). There was no significant difference between the RIPC and control group in terms of the complication rate.

CONCLUSION

The RIPC was evaluated to have a strong hepatoprotective effect from ischemia-reperfusion injury in the liver related surgery.

TNFAIP3 Interacting Protein 3 Is an Activator of Hippo-YAP Signaling Protecting Against Hepatic Ischemia/Reperfusion Injury

BACKGROUND AND AIMS

Hepatic ischemia/reperfusion (I/R) injury, a common clinical problem that occurs during liver surgical procedures, causes a large proportion of early graft failure and organ rejection cases. The identification of key regulators of hepatic I/R injury may provide potential strategies to clinically improve the prognosis of liver surgery. Here, we aimed to identify the role of tumor necrosis factor alpha-induced protein 3-interacting protein 3 (TNIP3) in hepatic I/R injury and further reveal its immanent mechanisms.

APPROACH AND RESULTS

In the present study, we found that hepatocyte TNIP3 was markedly up-regulated in livers of both persons and mice subjected to I/R surgery. Hepatocyte-specific Tnip3 overexpression effectively attenuated I/R-induced liver necrosis and inflammation, but improved cell proliferation in mice, whereas TNIP3 ablation largely aggravated liver injury. This inhibitory effect of TNIP3 on hepatic I/R injury was found to be dependent on significant activation of the Hippo-YAP signaling pathway. Mechanistically, TNIP3 was found to directly interact with large tumor suppressor 2 (LATS2) and promote neuronal precursor cell-expressed developmentally down-regulated 4-mediated LATS2 ubiquitination, leading to decreased Yes-associated protein (YAP) phosphorylation at serine 112 and the activated transcription of factors downstream of YAP. Notably, adeno-associated virus delivered TNIP3 expression in the liver substantially blocked I/R injury in mice.

CONCLUSIONS

TNIP3 is a regulator of hepatic I/R injury that alleviates cell death and inflammation by assisting ubiquitination and degradation of LATS2 and the resultant YAP activation.TNIP3 represents a promising therapeutic target for hepatic I/R injury to improve the prognosis of liver surgery.

Cellular communication network factor 1 (CCN1) knockdown exerts a protective effect for hepatic ischemia/reperfusion injury by deactivating the MEK/ERK pathway

OBJECTIVE

Hepatic ischemia/reperfusion injury (IRI) is an unsettled and intractable conundrum in clinical treatment after liver transplantation and resection. Cellular communication network factor 1 (CCN1) is upregulated in liver IRI and may play a key role in this process. The objective of this study is to investigate the regulatory mechanism of CCN1 in liver IRI, which may provide new insight into liver IRI clinical treatment.

METHODS

The hepatic ischemia/reperfusion model was established in male C57BL/6 mice by occlusion of vessels in the liver followed by reperfusion. The mice were transfected with two small interfering RNAs (siRNAs) against CCN1 for CCN1 knockdown. The hypoxia/reoxygenation (HR) model was established in vitro using mouse hepatic cells followed by transfection with a siRNA and treatment with an ERK activator TPA to confirm the effects of CCN1 on the MEK/ERK pathway in liver IRI.

RESULTS

In hepatic IRI, CCN1 was upregulated and its knockdown reduced alanine aminotransferase and aspartate transaminase levels, myeloperoxidase activity, and the levels of IL-6 and TNF-α. CCN1 downregulation alleviated inflammatory cell infiltration and apoptosis in the liver. The expressions of cleaved caspase-9, cleaved caspase-3, Bax, and CHOP were decreased with an increased Bcl-2 level after CCN1 knockdown. The phosphorylation and activation of proteins in ER stress and MEK/ERK pathway were inhibited by CCN1 knockdown. In vitro, the levels of proinflammatory cytokines, apoptosis-inducing proteins, and proteins in ER stress and MEK/ERK pathway, which were decreased by CCN1 knockdown in HR, were restored by TPA, confirming that the activation of ERK aggravated cell apoptosis after reoxygenation.

CONCLUSION

Overall, CCN1 knockdown may suppress the inflammation, apoptosis during hepatic IRI by reducing the MEK/ERK pathway activation, which may be a breakthrough point in clinical alleviation of hepatic IRI caused by liver transplantation and resection.

Effect of Remote Ischemic Conditioning on Bleeding Complications in Surgery: A Systematic Review and Meta-Analysis

Remote ischemic conditioning (RIC) is administered with an inflatable tourniquet by inducing brief, alternating cycles of limb ischemia and reperfusion. RIC possibly impacts the hemostatic system, and the intervention has been tested as protective therapy against ischemia-reperfusion injury and thrombotic complications in cardiac surgery and other surgical procedures. In the present systematic review, we aimed to investigate the effect of RIC on intraoperative and postoperative bleeding complications in meta-analyses of randomized controlled trials including adult patients undergoing surgery. A systematic search was performed on November 7, 2020 in PubMed, Embase, and the Cochrane Central Register of Controlled Trials. Randomized controlled trials comparing RIC versus no RIC in adult patients undergoing surgery that reported bleeding outcomes in English publications were included. Effect estimates with 95% confidence intervals were calculated using the random-effects model for intraoperative and postoperative bleeding outcomes. Thirty-two randomized controlled trials with 3,804 patients were eligible for inclusion. RIC did not affect intraoperative bleeding volume (nine trials; 392 RIC patients, 399 controls) with the effect estimate -0.95 [-9.90; 7.99] mL (p = 0.83). RIC significantly reduced postoperative drainage volume (seven trials; 367 RIC patients, 365 controls) with mean difference -83.6 [-134.9; -32.4] mL (p = 0.001). The risk of re-operation for bleeding was reduced in the RIC group (16 trials; 838 RIC patients, 839 controls), albeit not significantly, with the relative risk 0.65 [0.39; 1.09] (p = 0.10). In conclusion, RIC reduced postoperative bleeding measured by postoperative drainage volume in this meta-analysis of adult patients undergoing surgery.

Tetramethylpyrazine inhibits neutrophil extracellular traps formation and alleviates hepatic ischemia/reperfusion injury in rat liver transplantation

Hepatic ischemia/reperfusion injury (IRI) is an adverse effect for liver transplantation which is characterized by immune response mediated inflammation. Recent studies report that neutrophil extracellular traps (NETs) are implicated in hepatic IRI. The aim of this study was to explore the mechanism of action of tetramethylpyrazine (TMP), the main chemical composition of Ligusticum chuanxiong in treatment of ischemic related diseases. Data showed that hepatic IRI increases the leak of alanine aminotransferase (ALT) and aspartate transaminase (AST), and stimulates formation of NETs. Extracellular DNA/NETs assay, hematoxylin-eosin (HE) staining, immunofluorescence assay, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) and Western blot assay, showed that TMP significantly reduces formation of NETs and alleviates hepatic IRI. Moreover, TMP and Diphenyleneiodonium (DPI) suppressed ROS production in neutrophils. In addition, analysis showed that activation of NADPH oxidase plays a role in formation of NETs triggered by hepatic IRI. Notably, TMP inhibited formation of NETs though inhibition of NADPH oxidase. Additionally, Combination treatment using TMP and DPI was more effective compared with monotherapy of either of the two drugs. These findings show that combination therapy using TMP and DPI is a promising method for treatment hepatic IRI.

Direct, remote and combined ischemic conditioning in liver surgery

Liver ischemia-reperfusion injury is a major cause of postoperative liver dysfunction, morbidity and mortality following liver resection and transplantation. Ischemic conditioning has been shown to ameliorate ischemia-reperfusion injury in small animal models. It can be applied directly or remotely when cycles of ischemia and reperfusion are applied to a distant site or organ. Considering timing of the procedure, different protocols are available. Ischemic preconditioning refers to that performed before the duration of ischemia of the target organ. Ischemic perconditioning is performed over the duration of ischemia of the target organ. Ischemic postconditioning applies brief episodes of ischemia at the onset of reperfusion following a prolonged ischemia. Animal studies pointed towards suppressing cytokine release, enhancing the production of hepatoprotective adenosine and reducing liver apoptotic response as the potential mechanisms responsible for the protective effect of direct tissue conditioning. Interactions between neural, humoral and systemic pathways all lead to the protective effect of remote ischemic preconditioning. Despite promising animal studies, none of the aforementioned protocols proved to be clinically effective in liver surgery with the exception of morbidity reduction in cirrhotic patients undergoing liver resection. Further human clinical trials with application of novel conditioning protocols and combination of methods are warranted before implementation of ischemic conditioning in day-to-day clinical practice.

Laparoscopic vs. Open Repeat Hepatectomy for Recurrent Liver Tumors: A Propensity Score-Matched Study and Meta-Analysis

Background: It remains unclear whether the short-term benefits of laparoscopic repeat hepatectomy (LRH) accrue to patients with recurrent liver tumors. The present study aimed to report our own center's experience and perform a meta-analysis to evaluate the safety and feasibility of LRH in comparison with open repeat hepatectomy (ORH) for treating recurrent liver tumors.

Patients and Methods: A propensity score–matched study was performed including 426 patients receiving LRH or ORH for recurrent hepatocellular carcinoma between January 2017 and December 2018. Surgical outcomes and perioperative inflammation-based markers, including monocyte-to-lymphocyte ratio, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and systemic immune–inflammation index were collected from medical records and analyzed. Additionally, a systematic literature review was performed to identify relevant studies in PubMed, EMBASE, Web of Science, and Cochrane library databases up to October 1, 2020. Information including patient demographics, pathologic characteristics, and short-term outcomes was extracted and analyzed using random- or fixed-effects models.

Results: Of 68 LRHs, 57 were matched with an ORH finally. Our study demonstrated that LRH was significantly associated with less intraoperative blood loss (50 vs. 100 mL; P < 0.001), lower rate of hepatic inflow occlusion (10.52 vs. 33.3%; P = 0.003), and shorter postoperative hospital stay (5 vs. 6 days; P = 0.001) after 1:1 propensity score matching. The operation time, rate of blood transfusion, and postoperative complications were similar between the two groups. Moreover, all four inflammation-based markers were significantly lower in LRH group on postoperative day 1. In the meta-analysis, a total of 12 studies comprising 1,315 patients receiving repeat hepatectomy met the selection criteria. Similar to our own study, the meta-analysis showed shorter hospital stay [standard mean difference (SMD) = −0.51, 95% confidence interval (CI) = −0.79 to −0.22, P < 0.001], less intraoperative blood loss (SMD = −0.79, 95% CI = −1.11 to −0.47, P < 0.001), and lower rate of major postoperative complications [odds ratio (OR) = 0.35, 95% CI = 0.19–0.66, P = 0.001] in the LRH group. There was no difference in the field of overall postoperative complication and operation time between LRH and ORH groups.

Conclusion: Compared with ORH, LRH results in relatively better surgical outcomes and faster postoperative recovery. It could be considered a feasible and effective option for the treatment of recurrent liver tumors.

To Protect Fatty Livers from Ischemia Reperfusion Injury: Role of Ischemic Postconditioning

BACKGROUND

The benefit of ischemic postconditioning (IPostC) might be the throttled inflow following cold ischemia. The current study investigated advantage and mechanisms of IPostC in healthy and fatty rat livers.

METHODS

Male SD rats received a high-fat diet to induce fatty livers. Isolated liver perfusion was performed after 24 h ischemia at 4 °C as well as in vivo experiments after 90 min warm ischemia. The so-called follow-up perfusions served to investigate the hypothesis that medium from IPostC experiments is less harmful. Lactate dehydrogenase (LDH), transaminases, different cytokines, and gene expressions, respectively, were measured.

RESULTS

Fatty livers showed histologically mild inflammation and moderate to severe fat storage. IPostC reduced LDH and TXB₂ in healthy and fatty livers and increased bile flow. LDH, TNF-α, and IL-6 levels in serum decreased after warm ischemia + IPostC. The gene expressions of Tnf, IL-6, Ccl2, and Ripk3 were downregulated in vivo after IPostC.

CONCLUSIONS

IPostC showed protective effects after ischemia in situ and in vivo in healthy and fatty livers. Restricted cyclic inflow was an important mechanism and further suggested involvement of necroptosis. IPostC represents a promising and easy intervention to improve outcomes after transplantation.

Ischemia/Reperfusion Injury in the Aged Liver: The Importance of the Sinusoidal Endothelium in Developing Therapeutic Strategies for the Elderly

The liver endothelium plays a key role in the progression and resolution of liver diseases in young and adult individuals. However, its role in older people remains unknown. We have herein evaluated the importance of the sinusoidal endothelium in the pathophysiology of acute liver injury, and investigated the applicability of simvastatin, in aged animals. Eighteen-months-old male Wistar rats underwent 60 minutes of partial warm ischemia followed by 2 hours of reperfusion (WIR). A group of aged rats received simvastatin for 3 days before WIR. Endothelial phenotype, parenchymal injury, oxidative and nitrosative stress, and fenestrae dynamics were analyzed. The effects of WIR and simvastatin were investigated in primary LSEC from aged animals. The results of this study demonstrated that WIR significantly damages the liver endothelium and its effects are markedly worse in old animals. WIR-aged livers exhibited reduced vasodilation and sinusoidal capillarization, associated with liver damage and cellular stress. Simvastatin prevented the detrimental effects of WIR in aged livers. In conclusion, the liver sinusoidal endothelium of old animals is highly vulnerable to acute insult, thus targeted protection is especially relevant in preventing liver damage. Simvastatin represents a useful therapeutic strategy in aging.

Protocol of supra-visceral aortic ischemic preconditioning for open surgical repair of thoracoabdominal aortic aneurysm : The EPICATA study (Evaluation of the Efficacy of Ischemic PreConditioning on morbidity and mortality in open ThoracoAbdominal Aortic surgery)

Background

Open surgical repair (OSR) for thoracoabdominal aortic aneurysms (TAA) is associated with a high pulmonary and renal morbidity rate. Ischemic preconditioning (IPC) is a mechanism of protection against the deleterious effects of ischemia-reperfusion. To our knowledge IPC has never been tested during OSR for TAA.

Methods

The primary objective of the study is to evaluate the efficacy of IPC during OSR for TAA with respect to acute kidney injury (AKI) according to KDIGO and pneumonia/prolonged ventilation-time during the first 8 postoperative days. The secondary objectives are to compare both arms with respect to cardiac complications within 48 h, renal and pulmonary complications within 21 days and mortality at 60 days.

To assess the efficacy of IPC with respect to pulmonary and renal morbidity, a cox model for competing risks will be used. Assuming that the event occurs among 36% of the patients when no IPC is performed, the allocation of 55 patients to each arm should allow detecting a hazard ratio of at least 2.75 with a power of 80% when admitting 5% for an error of first kind. This means that 110 patients, enrolled in this multicenter study, may be randomised within 36 months of the first randomization.

Randomization will be performed to allocate patients either to surgery with preconditioning before aortic cross clamping (Arm 1) or to surgery without preconditioning before aortic cross clamping (Arm 2).

Randomization takes place during the intervention after intravenous injection of heparin, or after the start of femoral assistance. The procedure for IPC will be a supra-visceral thoracic aortic cross clamping for 5 min followed by an unclamping period of 5 min. This procedure will be repeated twice before starting thoracic aortic cross clamping needed to perform surgery.

Conclusions

Our hypothesis is that ischemic preconditioning could reduce clinical morbidity and the incidence of lung damage associated with supra-visceral aortic clamping.

Trial registration

EPICATAStudy registered in ClinicalTrial.gov / number: NCT03718312 on Oct.24.2018 URL number

Castro M, Sidoli S, Schwämmle V, Luz IS, Roepstorff P, Fontes W. Phosphoproteomic Analysis of Rat Neutrophils Shows the Effect of Intestinal Ischemia/Reperfusion and Preconditioning on Kinases and Phosphatases

Intestinal ischemia reperfusion injury (iIRI) is a severe clinical condition presenting high morbidity and mortality worldwide. Some of the systemic consequences of IRI can be prevented by applying ischemic preconditioning (IPC), a series of short ischemia/reperfusion events preceding the major ischemia. Although neutrophils are key players in the pathophysiology of ischemic injuries, neither the dysregulation presented by these cells in iIRI nor the protective effect of iIPC have their regulation mechanisms fully understood. Protein phosphorylation, as well as the regulation of the respective phosphatases and kinases are responsible for regulating a large number of cellular functions in the inflammatory response. Moreover, in previous work we found hydrolases and transferases to be modulated in iIR and iIPC, suggesting the possible involvement of phosphatases and kinases in the process. Therefore, in the present study, we analyzed the phosphoproteome of neutrophils from rats submitted to mesenteric ischemia and reperfusion, either submitted or not to IPC, compared to quiescent controls and sham laparotomy. Proteomic analysis was performed by multi-step enrichment of phosphopeptides, isobaric labeling, and LC-MS/MS analysis. Bioinformatics was used to determine phosphosite and phosphopeptide abundance and clustering, as well as kinases and phosphatases sites and domains. We found that most of the phosphorylation-regulated proteins are involved in apoptosis and migration, and most of the regulatory kinases belong to CAMK and CMGC families. An interesting finding revealed groups of proteins that are modulated by iIR, but such modulation can be prevented by iIPC. Among the regulated proteins related to the iIPC protective effect, Vamp8 and Inpp5d/Ship are discussed as possible candidates for control of the iIR damage.

Laparoscopic hepatectomy enhances recovery for small hepatocellular carcinoma with liver cirrhosis by postoperative inflammatory response attenuation: a propensity score matching analysis with a conventional open approach

BACKGROUND

The concurrent presence of liver cirrhosis and hepatocellular carcinoma (HCC) poses a challenge for laparoscopic surgeons to establish a routine practice. The aim of this study was to gather evidence and produce recommendations on the safe and effective practice of laparoscopic hepatectomy for patients with solitary HCC (≤ 5 cm) and liver cirrhosis.

METHODS

Between October 2013 and October 2014, 356 curative hepatectomies were performed for patients pathologically diagnosed with solitary HCC (≤ 5 cm) accompanied by cirrhosis (stage 4 fibrosis). To overcome selection bias, a 1:2 match using propensity score matching analysis was conducted between laparoscopic and open hepatectomy. Perioperative outcomes were compared between the groups, including hospitalization, operation time, blood loss, and surgical complications. Perioperative inflammation-based markers, including systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR) were collected from medical records and analyzed.

RESULTS

There were 43 and 77 patients in the laparoscopic and open groups, respectively. The laparoscopic group had less hepatic inflow occlusion (16.3% vs. 61%; P < 0.001), shorter operation time (155 vs. 170 min; P = 0.004), and shorter postoperative hospital stay (4 vs. 7 days; P < 0.001). Although the difference was not significant (P = 0.154), the rate of postoperative complications tended to be lower in the laparoscopic group (2.3%) compared with the open group (9.1%). The increase in postoperative SII, NLR, and LMR for laparoscopic hepatectomy were significantly lower than for open hepatectomy. NLR < 5.8 on postoperative day 3 was significantly correlated with shorter hospital stay (P < 0.001).

CONCLUSIONS

Compared with open hepatectomy, laparoscopic hepatectomy for selected HCC patients, even in the presence of cirrhosis, might result in better perioperative outcomes and postoperative inflammatory response attenuation, and ultimately promote faster recovery. This provides evidence for considering routine laparoscopic hepatectomy through careful selection of patients with HCC.

Laparoscopic Versus Open Left Lateral Segmentectomy for Large Hepatocellular Carcinoma: A Propensity Score-Matched Analysis

BACKGROUND

With the advancement of endoscopic technology, laparoscopic liver resection has become the standard procedure for left lateral segmentectomy. The aim of this study was to compare perioperative and oncological outcomes between laparoscopic and open left lateral segmentectomy for hepatocellular carcinoma (HCC) >5 cm.

PATIENTS AND METHODS

A total of 66 patients underwent left lateral segmentectomy for HCC (>5 cm) during the period spanning between 2013 and 2015. To overcome selection bias, 1:3 match using propensity score-matched analysis was performed between laparoscopic and open liver resection.

RESULTS

Relatively smaller tumor size (6.0 vs. 7.0 cm; P=0.030) and more frequent incidence of complete tumor capsule (93.3% vs. 58.8%; P=0.013) were observed in the laparoscopic group compared with the open group before matching. Although the longer operation time (195 vs. 150 min; P=0.022) was consumed in the laparoscopic procedure after matching, the laparoscopic group had shorter postoperative hospital stay (6 vs. 7 d; P=0.002) and less blood loss volume (50 vs. 100 mL; P=0.022). The Pringle maneuver for hepatic inflow occlusion was more likely to be applied in patients who underwent open surgery. The incidence of postoperative complication seemed to be lower in the laparoscopic group (6.7%) compared with that in the open group (11.8%) before matching. On the basis of propensity score-matched analysis, the complication rates were comparable between the 2 groups (7.1% vs. 6.7%, P=0.953). No difference in the 1-year and 3-year overall and recurrence-free survival rates was found between the laparoscopic and open groups.

CONCLUSION

Laparoscopic left lateral segmentectomy for large HCC patients showed better perioperative outcomes and equivalent oncologic outcomes as the open procedure, providing evidence for considering as a standard laparoscopic practice through careful selection.

Interpatient heterogeneity in hepatic microvascular blood flow during vascular inflow occlusion (Pringle manoeuvre)

BACKGROUND

Vascular inflow occlusion (VIO) during liver resections (Pringle manoeuvre) can be applied to reduce blood loss, however may at the same time, give rise to ischemia-reperfusion injury (IRI). The aim of this study was to assess the characteristics of hepatic microvascular perfusion during VIO in patients undergoing major liver resection.

METHODS

Assessment of hepatic microcirculation was performed using a handheld vital microscope (HVM) at the beginning of surgery, end of VIO (20 minutes) and during reperfusion after the termination of VIO. The microcirculatory parameters assessed were: functional capillary density (FCD), microvascular flow index (MFI) and sinusoidal diameter (SinD).

RESULTS

A total of 15 patients underwent VIO; 8 patients showed hepatic microvascular perfusion despite VIO (partial responders) and 7 patients showed complete cessation of hepatic microvascular perfusion (full responders). Functional microvascular parameters and blood flow levels were significantly higher in the partial responders when compared to the full responders during VIO (FCD: 0.84±0.88 vs. 0.00±0.00 mm/mm2, P<0.03, respectively, and MFI: 0.69-0.22 vs. 0.00±0.00, P<0.01, respectively).

CONCLUSIONS

An interpatient heterogeneous response in hepatic microvascular blood flow was observed upon VIO. This may explain why clinical strategies to protect the liver against IRI lacked consistency.

Laparoscopic Liver Resection Ameliorates the Postoperative Liver Function Impairment for Hepatocellular Carcinoma Patients

To study whether laparoscopic liver resection (LLR) is able to alleviate the postoperative liver function impairment for hepatocellular carcinoma patients, the clinical data of 103 patients were retrospectively analyzed, including 42 patients who underwent LLR and 61 patients who underwent open liver resection (OLR), during the period spanning from 2012 to 2017. The postoperative peak aspartate aminotransferase and alanine aminotransferase levels in the LLR group were significantly lower than those of the OLR group (209.76±189.516 vs. 262.55±181.19, P=0.046; 250.56±200.944 vs. 411.01±412.51, P=0.005, for aspartate aminotransferase and alanine aminotransferase, respectively). The recovering of postoperative total protein and albumin in the LLR group was faster than that in the OLR group, and the total protein and albumin levels on the postoperative day-5 were significantly higher in the LLR group than in the OLR group (62.528±9.427 vs. 57.87±6.101, P=0.019; 36.456±4.875 vs. 33.653±4.112, P=0.012, respectively). In conclusion, these data show that LLR alleviates postoperative liver function impairment and increases liver function recovery.

Vagus Nerve Stimulation Alleviates Hepatic Ischemia and Reperfusion Injury by Regulating Glutathione Production and Transformation

Inflammation and oxidative stress are pivotal mechanisms for the pathogenesis of ischemia and reperfusion injury (IRI). Vagus nerve stimulation (VNS) may participate in maintaining oxidative homeostasis and response to external stimulus or injury. We investigated whether the in vivo VNS can protect the liver from IRI. In this study, hepatic IRI were induced by ligating the vessels supplying the left and middle lobes of the liver, which underwent 1 h occlusion followed with 24 h reperfusion. VNS was initiated 15 min after ischemia and continued 30 min. Hepatic function, histology, and apoptosis rates were evaluated after 24 h reperfusion. Compared with the IRI group, VNS significantly improved hepatic function. The protective effect was accompanied by a reduction in histological damage in the ischemic area, and the apoptosis rate of hepatocytes has considerable reduction. To find the underlying mechanism, proteomic analysis was performed and differential expression of glutathione synthetase (GSS) and glutathione S-transferase (GST) was observed. Subsequently, test results indicated that VNS upregulated the expression of mRNA and protein of GSS and GST. Meanwhile, VNS increased the plasma levels of glutathione and glutathione peroxidases. We found that VNS alleviated hepatic IRI by upregulating the antioxidant glutathione via the GSS/glutathione/GST signaling pathway.

Transcriptional changes during hepatic ischemia-reperfusion in the rat

There are few effective targeted strategies to reduce hepatic ischemia-reperfusion (IR) injury, a contributor to poor outcomes in liver transplantation recipients. It has been proposed that IR injury is driven by the generation of reactive oxygen species (ROS). However, recent studies implicate other mediators of the injury response, including mitochondrial metabolic dysfunction. We examined changes in global gene expression after transient hepatic ischemia and at several early reperfusion times to identify potential targets that could be used to protect against IR injury. Male Wistar rats were subjected to 30 minutes of 70% partial warm ischemia followed by 0, 0.5, 2, or 6 hours of reperfusion. RNA was extracted from the reperfused and non-ischemic lobes at each time point for microarray analysis. Identification of differentially expressed genes and pathway analysis were used to characterize IR-induced changes in the hepatic transcriptome. Changes in the reperfused lobes were specific to the various reperfusion times. We made the unexpected observation that many of these changes were also present in tissue from the paired non-ischemic lobes. However, the earliest reperfusion time, 30 minutes, showed a marked increase in the expression of a set of immediate-early genes (c-Fos, c-Jun, Atf3, Egr1) that was exclusive to the reperfused lobe. We interpreted these results as indicating that this early response represented a tissue autonomous response to reperfusion. In contrast, the changes that occurred in both the reperfused and non-ischemic lobes were interpreted as indicating a non-autonomous response resulting from hemodynamic changes and/or circulating factors. These tissue autonomous and non-autonomous responses may serve as targets to ameliorate IR injury.

Effect of remote ischemic preconditioning on hepatic ischemia-reperfusion injury in patients undergoing liver resection: a randomized controlled trial

BACKGROUND

Studies in animal models have shown that remote ischemic preconditioning (RIPC) could protect the liver from hepatic ischemia-reperfusion injury (HIRI). The aim of this study was to examine whether RIPC could reduce HIRI in patients undergoing liver resection.

METHODS

A total of 120 patients were randomly assigned to three groups: a control group receiving no conditioning, an ischemic preconditioning (IPC) group, and an RIPC group. In the IPC group, the hepatoduodenal ligament was blocked for 10 min followed by 10 min of reperfusion prior to hepatic resection. Patients in the RIPC group received three cycles of 5-min ischemia followed by 5-min reperfusion to the right arm. Alanine transaminase (ALT), aspartate transaminase (AST), and tumor necrosis factor-like weak inducer of apoptosis (TWEAK) were examined before and after surgery.

RESULTS

A total of 105 patients completed the trial: 39 in the control group, 32 in the IPC group, and 34 in the RIPC group. In comparison to the control, serum ALT and AST levels significantly decreased in the IPC (ALT: 507.0±401.3 vs. 1040.7±649.5 IU/L, P<0.001; AST: 495.8±369.4 vs. 935.9±640.7 IU/L, P=0.001) and RIPC (ALT: 680.8±291.5 vs. 1040.7±649.5 IU/L, P=0.002; AST: 661.7±290.6 vs. 935.9±640.7 IU/L, P=0.014) groups on the first postoperative day. In comparison to the control, TWEAK significantly decreased in the IPC group (IPC 57.99±17.8 vs. control 76.13±12.4 ng/L, P=0.025) after surgery. TWEAK did not differ between the RIPC and IPC groups (RIPC 64.84±14.2 vs. IPC 57.99±17.8 ng/L, P=0.385).

CONCLUSIONS

RIPC could reduce hepatic ischemia-reperfusion injury after liver resection.

Effect of Remote Ischemic Preconditioning in Patients Undergoing Hepatectomy With Portal Triad Clamping: A Randomized Controlled Trial

BACKGROUND

Remote ischemic preconditioning (RIPC) is reported to reduce liver injury in patients undergoing hepatectomy for colorectal liver metastasis, but its role is unclear in hepatocellular carcinoma patients with portal triad clamping during hepatectomy.

METHODS

In this prospective, randomized trial, 140 patients with hepatocellular carcinoma undergoing liver resection requiring portal triad clamping were randomized to a RIPC group or a control group. Patients in the RIPC group received RIPC (3 cycles of 5-minute ischemia and 5-minute reperfusion in right upper limb with cuff pressure at 30 kPa [225 mm Hg]) approximately 10 minutes after induction of anesthesia. In the control group, patients received sham RIPC (the cuff was not inflated). The primary outcome was the postoperative peak level of total bilirubin (TBIL) and was analyzed with the independent t test. Secondary outcomes were liver function test at postoperative days 1, 3, and 5; postoperative morbidity and mortality during the first month; and the length of postoperative hospital stay.

RESULTS

Data from 136 patients (69 in the RIPC group and 67 in the control group) were analyzed. The RIPC group had on average a 5.9 μmol lower peak level of TBIL than the control group; the mean difference is -5.9, and the 95% confidence interval (CI) reverses to -17.9 to 6.1. There were no significant differences between the 2 groups in liver function test at postoperative days 1, 3, and 5; postoperative morbidity and mortality during the first month; and the length of postoperative hospital stay.

CONCLUSIONS

We found no evidence that RIPC can reduce postoperative liver injury after hepatectomy.

Integrated Omics Reveals Tollip as an Regulator and Therapeutic Target for Hepatic Ischemia-Reperfusion Injury in Mice

Hepatic ischemia-reperfusion (IR) injury is the leading cause of liver dysfunction and failure after liver resection or transplantation and lacks effective therapeutic strategies. Here, we applied a systematic proteomic analysis to identify the prominent contributors to IR-induced liver damage and promising therapeutic targets for this condition. Based on an unbiased proteomic analysis, we found that toll-interacting protein (Tollip) expression was closely correlated with the hepatic IR process. RNA sequencing analysis and phenotypic examination showed a dramatically alleviated hepatic IR injury by Tollip deficiency both in vivo and in hepatocytes. Mechanistically, Tollip interacts with apoptosis signal-regulating kinase 1 (ASK1) and facilitates the recruitment of tumor necrosis factor receptor-associated factor 6 (TRAF6) to ASK1, leading to enhanced ASK1 N-terminal dimerization and the subsequent activation of downstream mitogen-activated protein kinase (MAPK) signaling. Furthermore, the Tollip methionine and phenylalanine motif and TRAF6 ubiquitinating activity are required for Tollip-regulated ASK1-MAPK axis activation. Conclusion: Tollip is a regulator of hepatic IR injury by facilitating ASK1 N-terminal dimerization and the resultant c-Jun N-terminal kinase/p38 signaling activation. Inhibiting Tollip or its interaction with ASK1 might be promising therapeutic strategies for hepatic IR injury.

miR-219a-5p Ameliorates Hepatic Ischemia/Reperfusion Injury via Impairing TP53BP2

BACKGROUND

Hepatic ischemia/reperfusion (I/R) injury is a serious complication that occurs upon hypovolemic shock, liver resection, and transplantation. A significant age-dependent difference in the injury response to hepatic I/R in both human and animal models has been reported. Nevertheless, the molecular mechanism is currently unclear.

AIMS

To clarify the reason why aged animals or people were more vulnerable to hepatic I/R injury.

METHODS

In the present study, we found decreased miR-219a-5p expression in the old mice more vulnerable to hepatic I/R injury. Administrated with agomir-miR-219a-5p diminished the severity of hepatic I/R injury in old mice, as indicated by lower serum ALT and AST, oxidative parameters including MDA, TOA, and OSI, and decreased apoptotic cell number. The effect of miR-219a-5p was also confirmed in the H₂O₂-induced apoptosis model in AML-12 and NCTC1469 cells. After miR-219a-5p overexpression, two key apoptosis-related proteins Bax and P21, target genes of TP53, were decreased. Furthermore, TP53BP2 interacts with p53 family members and promotes their transcriptional activities toward pro-apoptosis genes.

RESULTS

RNA sequencing, western blot, and luciferase reporter assay proved that TP53BP2, a crucial TP53 transcriptional activity enhancer in vivo, was directly regulated by miR-219a-5p.

CONCLUSIONS

In summary, our study demonstrated that age-related miR-219a-5p can attenuate hepatic I/R injury through inhibiting TP53BP2 and downstream TP53-dependent apoptosis of hepatic cells in mice.

Combined ischemic and rapamycin preconditioning alleviated liver ischemia and reperfusion injury by restoring autophagy in aged mice

Old livers are more damaged by hepatic ischemia and reperfusion (IR) injury than young livers. The aim of this study was to investigate the effects of ischemic and rapamycin preconditioning on IR injury in old livers. Young (8-week-old) and aged (60-week-old) mice were subjected to IR or a sham control procedure. The aged mice were randomly divided into six groups: IR (CON), IR with ischemic preconditioning (IPC), IR with rapamycin preconditioning (RAPA), IR with combined ischemic and rapamycin preconditioning (IPC + RAPA), IR with 3-methyladenine (3-MA), IR with combined ischemic and rapamycin preconditioning with 3-MA pretreatment (IPC + RAPA+3-MA). Liver injury was evaluated 6 h after reperfusion. Hepatocellular autophagy induction was also analyzed by western blotting. The results revealed that aged mice had aggravated liver IR injury as compared to young mice. In aged mice following IR, IPC + RAPA but not IPC or RAPA alleviated liver injury, as evidenced by lower levels of serum ALT, improved preservation of liver architecture with lower Suzuki scores, and decreased caspase-3 activity compared with CON. In addition, western blot analysis revealed increased LC3B II but decreased p62 protein expression levels in the IPC + RAPA group, indicating that autophagic flux was restored by combined ischemic and rapamycin preconditioning. Furthermore, autophagy inhibition by the inhibitor 3-MA abrogated the protective role in the IPC + RAPA group, while no significant effects were observed in the CON group. In conclusions, our results demonstrated that combined ischemic and rapamycin preconditioning protected old livers against IR injury, which was likely attributed to restored autophagy activation.

Effects of silibinin on hepatic warm ischemia-reperfusion injury in the rat model

OBJECTIVES

Liver ischemia-reperfusion injuries (I/RI) are typically the main causes of liver dysfunction after various types of liver surgery especially liver transplantation. Radical components are the major causes of such direct injuries. We aimed to determine the beneficial effects of silibinin, a potent radical scavenger on liver I/RI.

MATERIALS AND METHODS

Thirty-two rats were divided into 4 groups. Group I: VEHICLE, the rats underwent laparotomy and received DMSO, group II: SILI, laparotomy was done and silibinin was administered. Group III: I/R, the rats received DMSO and were subjected to a liver I/R procedure and group IV: I/R+SILI, the animals underwent the I/R procedure and received silibinin. After 1 hr of ischemia followed by 3 hr reperfusion, blood was collected to evaluate the serum marker of liver injuries. Hepatic tissue was harvested to investigate glycogen content, histological changes, and vasoregulatory gene expression.

RESULTS

Results showed that serum AST, ALT, LDH, GGT, ALP, and hyaluronic acid (HA) increased significantly in I/R group compared with the VEHICLE group. Silibinin reduced this elevation except for GGT. Silibinin inhibited hepatocyte vacuolization and degeneration, endothelium damages, sinusoidal congestion and inflammation, and glycogen depletion during I/R. ET-1 mRNA was overproduced in the I/R group compared with the VEHICLE group which was decreased by silibinin. KLF2 and eNOS expression was reduced during I/R compared with the VEHICLE group. Silibinin elevated KLF2 expression but had no meaningful effect on eNOS expression.

CONCLUSION

Silibinin protected the liver from I/RI. Silibinin could improve liver circulation by preventing sinusoidal congestion, inflammation, and perhaps modification of the vasoregulatory gene expression.

The Protective Effect of Magnesium Lithospermate B on Hepatic Ischemia/Reperfusion via Inhibiting the Jak2/Stat3 Signaling Pathway

Acute inflammation is an important component of the pathogenesis of hepatic ischemia/reperfusion injury (HIRI). Magnesium lithospermate B (MLB) has strong neuroprotective and cardioprotective effects. The purpose of this study was to determine whether MLB had underlying protective effects against hepatic I/R injury and to reveal the potential mechanisms related to the hepatoprotective effects. In this study, we first examined the protective effect of MLB on HIRI in mice that underwent 1 h ischemia followed by 6 h reperfusion. MLB pretreatment alleviated the abnormal liver function and hepatocyte damage induced by I/R injury. We found that serum inflammatory cytokines, including IL-6, IL-1β, and TNF-α, were significantly decreased by MLB during hepatic ischemia/reperfusion (I/R) injury, suggesting that MLB may alleviate hepatic I/R injury via inhibiting inflammatory signaling pathways. Second, we investigated the protein level of p-Jak2/Jak2 and p-Stat3/Stat3 using Western blotting and found that MLB could significantly inhibit the activation of the Jak2/Stat3 signaling pathway, which was further verified by AG490 in a mouse model. Finally, the effect of MLB on the Jak2/Stat3 pathway was further assessed in an in vitro model of RAW 264.7 cells; 1 µg/ml LPS induced the secretion of inflammatory mediators, including IL-6, TNF-α, and activation of the Jak2/Stat3 signaling pathway. MLB significantly inhibited the abnormal secretion of inflammatory factors and the activation of the Jak2/Stat3 signaling pathway in RAW264.7 cells. In conclusion, MLB was found for the first time to reduce inflammation induced by hepatic I/R via suppressing the Jak2/Stat3 pathway.

Mitogen Activated Protein Kinases in Steatotic and Non-Steatotic Livers Submitted to Ischemia-Reperfusion

We analyzed the participation of mitogen-activated protein kinases (MAPKs), namely p38, JNK and ERK 1/2 in steatotic and non-steatotic livers undergoing ischemia-reperfusion (I-R), an unresolved problem in clinical practice. Hepatic steatosis is a major risk factor in liver surgery because these types of liver tolerate poorly to I-R injury. Also, a further increase in the prevalence of steatosis in liver surgery is to be expected. The possible therapies based on MAPK regulation aimed at reducing hepatic I-R injury will be discussed. Moreover, we reviewed the relevance of MAPK in ischemic preconditioning (PC) and evaluated whether MAPK regulators could mimic its benefits. Clinical studies indicated that this surgical strategy could be appropriate for liver surgery in both steatotic and non-steatotic livers undergoing I-R. The data presented herein suggest that further investigations are required to elucidate more extensively the mechanisms by which these kinases work in hepatic I-R. Also, further researchers based in the development of drugs that regulate MAPKs selectively are required before such approaches can be translated into clinical liver surgery.

Randomized clinical trial of stapler hepatectomy versus LigaSure™ transection in elective hepatic resection

BACKGROUND

Previous studies have demonstrated stapler hepatectomy and use of various energy devices to be safe alternatives to the clamp-crushing technique in elective hepatic resection. In this randomized trial, the effectiveness and safety of stapler hepatectomy were compared with those of parenchymal transection with the LigaSure™ vessel sealing system.

METHOD

Patients scheduled for elective liver resection at two tertiary-care centres were randomized during surgery to stapler hepatectomy or transection with the LigaSure™ device. Total intraoperative blood loss was the primary efficacy endpoint. Transection time, duration of operation, perioperative complications and length of hospital stay were recorded as secondary endpoints.

RESULTS

A total of 138 patients were analysed, 69 in the LigaSure™ and 69 in the stapler hepatectomy group. Baseline characteristics were well balanced between the groups. Mean intraoperative blood loss was significantly higher in the LigaSure™ group than the stapler hepatectomy group: 1101 (95 per cent c.i. 915 to 1287) versus 961 (752 to 1170) ml (P = 0·028). The parenchymal transection time was significantly shorter in the stapler group (P = 0·005), as was the total duration of operation (P = 0·027). Surgical morbidity did not differ between the groups, nor did the grade of complications.

CONCLUSION

Stapler hepatectomy was associated with reduced blood loss and a shorter duration of operation than the LigaSure™ device for parenchymal transection in elective partial hepatectomy. Registration number: NCT01858987 (http://www.clinicaltrials.gov).

Aged kidneys are refractory to autophagy activation in a rat model of renal ischemia-reperfusion injury

Background

Ischemia-reperfusion (I/R) injury is the most common cause of acute kidney injury (AKI). Numerous therapeutic approaches for I/R injury have been studied, including autophagy, particularly in animal models of renal I/R injury derived from young or adult animals. However, the precise role of autophagy in renal ischemia-reperfusion in the aged animal model remains unclear. The purpose of this study was to demonstrate whether autophagy has similar effects on renal I/R injury in young and aged rats.

Materials and methods

All rats were divided into two age groups (3 months and 24 months) with each group being further divided into four subgroups (sham, I/R, I/R+Rap (rapamycin, an activator of autophagy), I/R+3-MA (3-methyladenine, an inhibitor of autophagy)). The I/R+Rap and I/R+3-MA groups were intraperitoneally injected with rapamycin and 3-MA prior to ischemia. We then measured serum levels of urea nitrogen, creatinine and assessed damage in the renal tissue. Immunohistochemistry was used to assess LC3-II and caspase-3, and Western blotting was used to evaluate the autophagy-related proteins LC3-II, Beclin-1 and P62. Apoptosis and autophagosomes were evaluated by TUNEL and transmission electron microscopy, respectively.

Results

Autophagy was activated in both young and aged rats by I/R and enhanced by rapamycin, although the level of autophagy was lower in the aged groups. In young rats, the activation of autophagy markedly improved renal function, reduced apoptosis in the renal tubular epithelial cells and the injury score in the renal tissue, thereby exerting protective effects on renal I/R injury. However, this level of protection was not present in aged rats.

Conclusion

Our data indicated that the activation of autophagy was ineffective in aged rat kidneys. These discoveries may have major implications in that severe apoptosis in aged kidneys might be refractory to antiapoptotic effect induced by the activation of autophagy.

Regional Ischemic Preconditioning Has Clinical Value in Cirrhotic HCC Through MAPK Pathways

BACKGROUND

This study assessed the clinical value of regional ischemic preconditioning (RIP) and the role of the mitogen-activated protein kinase (MAPK) pathways in the protective mechanism of RIP in cirrhotic hepatocellular carcinoma (HCC) patients undergoing hepatectomy.

METHODS

Liver resection was performed with hemi-hepatic vascular inflow occlusion (HHV) under RIP (RIP group) or with HHV alone (HHV group). Clinical data, surgical outcomes, and the levels of phosphorylated MAPKs before occlusion and 30 min after reperfusion were estimated.

RESULTS

HHV under RIP was associated with less intraoperative blood loss (300 vs. 400 ml; P = 0.042), postoperative plasma transfused (400 vs. 800 ml; P = 0.019), and a higher level of prothrombin activity at postoperative days 3, 5, and 7 compared to HHV alone. The level of phosphorylated ERK protein was significantly increased and the levels of phosphorylated p38 and JNK proteins were significantly decreased 30 min after reperfusion compared to HHV group in the RIP group.

CONCLUSIONS

HHV under RIP may have clinical value in cirrhotic HCC patients requiring resection and the protective mechanism of RIP may be associated with changes in the protein phosphorylation level of MAPK pathways.

Ischemia-Reperfusion Injury in Aged Livers-The Energy Metabolism, Inflammatory Response, and Autophagy

Because of the lack of adequate organs, the number of patients with end-stage liver diseases, acute liver failure or hepatic malignancies waiting for liver transplantation is constantly increasing. Accepting aged liver grafts is one of the strategies expanding the donor pool to ease the discrepancy between the growing demand and the limited supply of donor organs. However, recipients of organs from old donors may show an increased posttransplantation morbidity and mortality due to enhanced ischemia-reperfusion injury. Energy metabolism, inflammatory response, and autophagy are 3 critical processes which are involved in the aging progress as well as in hepatic ischemia-reperfusion injury. Compared with young liver grafts, impairment of energy metabolism in aged liver grafts leads to lower adenosine triphosphate production and an enhanced generation of free radicals, both aggravating the inflammatory response. The aggravated inflammatory response determines the extent of hepatic ischemia-reperfusion injury and augments the liver damage. Autophagy protects cells by removal of damaged organelles, including dysfunctional mitochondria, a process impaired in aging and involved in ischemia-reperfusion-related apoptotic cell death. Furthermore, autophagic degradation of cellular compounds relieves intracellular adenosine triphosphate level for the energy depressed cells. Strategies targeting the mechanisms involved in energy metabolism, inflammatory response, and autophagy might be especially useful to prevent the increased risk for ischemia-reperfusion injury in aged livers after major hepatic surgery.

Histopathological changes and onset of severe hepatic steatosis in rats fed a choline-free diet

Hepatic steatosis significantly increases morbidity and mortality associated with major liver surgery. Several rodent models of hepatic steatosis have been previously reported, which aimed to investigate the effect of various pharmaceutical agents and interventional procedures on the pathophysiology of steatotic liver. The aim of the present study was to investigate the time frame of severe hepatic steatosis in rats after they were fed a choline-free diet and any associated histopathological changes. The duration of feeding with a choline-free diet required to develop severe hepatic steatosis was investigated in Wistar rats. The severity of hepatic steatosis in liver specimens was evaluated at 8, 10, 12 and 14 weeks following the onset of the choline-free diet. Comparisons were made with rats receiving standardized laboratory food. Feeding rats for 12–13 weeks with a choline-free diet led to 66% fatty liver infiltration, which exceeded 68% after 14 weeks. Prior to 8 weeks, the fatty infiltration reached 43%, with a gradual increase revealing a stronger rate from 8–12 weeks and a gradual decline after 14 weeks. At 12–13 weeks the fatty infiltration was considered representative of severe hepatic steatosis. Macrovesicular fatty infiltration revealed a significant increase at a steady rate between 8 and 14 weeks, with evidence of the onset of lobular inflammation and steatohepatitis after 14 weeks of feeding with the choline-free diet. Microvesicular fatty infiltration demonstrated a lower growth rate between 8 and 12 weeks while maintaining a steady rate between 12 and 14 weeks. Mixed fatty infiltration maintained its steady rate of hepatic parenchyma from 8.8–9.5%. Rats fed with the standard laboratory diet did not demonstrate fatty infiltration >4.5%, so they did not develop hepatic steatosis. Developing an ideal model of hepatic steatosis is a particular challenge. The findings of the present study indicate that severe hepatic steatosis in rodents may lead to the development of steatohepatitis after feeding with a choline-free diet for at least 14 weeks. This model is of particular interest in experimental liver surgery and associated surgical maneuvers, and is easily reproducible.