Liver manipulation during liver surgery in humans is associated with hepatocellular damage and hepatic inflammation

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.

Exploratory Investigation of the Plasma Proteome Associated with the Endotheliopathy of Trauma

BACKGROUND

The endotheliopathy of trauma (EoT) is associated with increased mortality following injury. Herein, we describe the plasma proteome related to EoT in order to provide insight into the role of the endothelium within the systemic response to trauma.

METHODS

99 subjects requiring the highest level of trauma activation were included in the study. Enzyme-linked immunosorbent assays of endothelial and catecholamine biomarkers were performed on admission plasma samples, as well as untargeted proteome quantification utilizing high-performance liquid chromatography and tandem mass spectrometry.

RESULTS

Plasma endothelial and catecholamine biomarker abundance was elevated in EoT. Patients with EoT (n = 62) had an increased incidence of death within 24 h at 21% compared to 3% for non-EoT (n = 37). Proteomic analysis revealed that 52 out of 290 proteins were differentially expressed between the EoT and non-EoT groups. These proteins are involved in endothelial activation, coagulation, inflammation, and oxidative stress, and include known damage-associated molecular patterns (DAMPs) and intracellular proteins specific to several organs.

CONCLUSIONS

We report a proteomic profile of EoT suggestive of a surge of DAMPs and inflammation driving nonspecific activation of the endothelial, coagulation, and complement systems with subsequent end-organ damage and poor clinical outcome. These findings support the utility of EoT as an index of cellular injury and delineate protein candidates for therapeutic intervention.

Comparative outcomes of pure laparoscopic and open donor right hepatectomy: the first report from a Southeast Asian transplant center

Background

Pure laparoscopic donor right hepatectomy (PLDRH) can provide better operative outcomes for the donor than conventional open donor right hepatectomy (CODRH). However, the complexity of the procedure typically makes transplant teams reluctant to perform it, especially in low-volume transplant centers. We compared the outcomes of PLDRH and CODRH to demonstrate the feasibility of PLDRH in a low-volume transplant program.

Methods

We carried out a retrospective study of adult living donor liver transplantation in Chiang Mai University Hospital from January 2015 to March 2021. The patients were divided into a PLDRH group and a CODRH group. Baseline characteristics, operative parameters, and postoperative complications of donors and recipients were compared between the two groups.

Results

Thirty patients underwent donor hepatectomy between the dates selected (9 PLDRH patients and 21 CODRH patients). The baseline characteristics of the 2 groups were not significantly different. The median graft volume of the PLDRH group was 693.8 mL, which was not significantly different from that of the CODRH group (726.5 mL) The PLDRH group had a longer operative time than the CODRH group, but the difference was not statistically significant (487.5 min vs 425.0 min, p = 0.197). The overall complication rate was not significantly different between the two groups (33.3% vs 22.2%, p = 0.555). Additionally, for the recipients, the incidence of major complications was not significantly different between the groups (71.3 vs 55.6%, p = 0.792).

Conclusion

Even in the context of this low-volume transplant program, whose staff have a high level of experience in minimally invasive hepatobiliary surgery, PLDRH showed similar results to CODRH in terms of perioperative outcomes for donors and recipients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-022-01507-0.

Influence of Large Grafts Weighing ≥ 1000 g on Outcome of Pure Laparoscopic Donor Right Hepatectomy

BACKGROUND

Depending on a transplant center's level of experience, utilization of pure laparoscopic donor right hepatectomy (PLDRH) may be limited due to graft size or anatomical variations. Here, we aimed to evaluate the influence of large hepatic grafts (≥ 1000 g) when performing PLDRH in both donors and recipients of such grafts.

METHODS

Medical records of living donors who underwent either PLDRH from November 2015 to August 2019 or open conventional donor right hepatectomy (CDRH) from January 2010 to August 2019 and those of the graft recipients were retrospectively reviewed. Donors were separated into three groups: PLDRH graft ≥ 1000 g (n = 10; study group), PLDRH graft < 1000 g (n = 280; control-I group), and CDRH graft ≥ 1000 g (n = 24; control-II group).

RESULTS

Total operative duration (P = 0.017) and warm ischemia time (P < 0.001) were significantly longer in the study than in the control-I and control-II groups, respectively. ΔAlanine aminotransferase% was significantly lower in the study than in the control-I group (P = 0.001). There was no significant difference in minor complication incidence between the study and control-I (P = 0.068) and control-II (P = 0.618) donors. There were no major complications in the study and control-II donors, whereas six control-I donors (2.1%) experienced a major complication (P = 1.000). Length of hospitalization was significantly shorter in the study than in the control-II group (P < 0.001). There was no significant difference in early and late major complication incidence for recipients between the study and control-I and control-II groups.

CONCLUSIONS

PLDRH for grafts weighing ≥ 1000 g appears to be safe and feasible when performed by experienced surgeons in a well-equipped center.

Bile Salt and FGF19 Signaling in the Early Phase of Human Liver Regeneration

The involvement of bile salt-fibroblast growth factor 19 (FGF19) signaling in human liver regeneration (LR) is not well studied. Therefore, we studied aspects of bile salt-FGF19 signaling shortly after liver resection in patients. We compared plasma bile salt and FGF19 levels in arterial, portal and hepatic venous blood, calculated venous-arterial differences (ΔVA), and determined hepatic transcript levels on two intra-operative time points: before (< 1 hour) and immediately after (> 2-3 hours) liver resection (i.e., following surgery). Postoperative bile salt and FGF19 levels were assessed on days 1, 2, and 3. LR was studied by computed tomography (CT)-liver volumetry. Following surgery, the liver, arterial, and portal bile salt levels were elevated (P < 0.05). Furthermore, an increased amount of bile salts was released in portal blood and extracted by the remnant liver (P < 0.05). Postoperatively, bile salt levels were elevated from day 1 onward (P < 0.001). For FGF19, intra-operative or postoperative changes of ΔVA or plasma levels were not observed. The bile salt-homeostatic regulator farnesoid X receptor (FXR) was markedly up-regulated following surgery (P < 0.001). Cell-cycle re-entry priming factors (interleukin 6 [IL-6], signal transducer and activator of transcription 3 [STAT3], and cJUN) were up-regulated following surgery and were positively correlated with FXR expression (P < 0.05). Postoperative hyperbilirubinemia was preceded by postsurgery low FXR and high Na+/Taurocholate cotransporting polypeptide (NTCP) expression in the remnant liver coupled with higher liver bile salt content (P < 0.05). Finally, bile salt levels on postoperative day 1 were an independent predictor of LR (P < 0.05). Conclusion: Systemic, portal, and liver bile salt levels are rapidly elevated after liver resection. Postoperative bile salts were positively associated with liver volume gain. In the studied time frame, FGF19 levels remained unaltered, suggesting that FGF19 plays a minor role in human LR. These findings indicate a more relevant role of bile salts in human LR.

Effect of pharmacological preconditioning with sevoflurane during hepatectomy with intermittent portal triad clamping

BACKGROUND

During hepatectomy, intermittent portal triad clamping (IPC) reduces ischemia-reperfusion injuries. Pharmacological preconditioning with sevoflurane revealed similar properties. The aim of the study was to evaluate the combination of a sevoflurane preconditioning regimen with IPC on ischemia-reperfusion injuries.

METHODS

Three regimens of anesthesia were applied: group SEV with continuous application of sevoflurane, group PRO with continuous propofol infusion and group PC where continuous propofol was substituted by sevoflurane (adjusted to reach MAC∗1.5) for 15 min before IPC. Endpoints were the values of AST and ALT, factor V, prothrombin time, bilirubinemia over the 5-postoperative days (POD), morbidity and mortality at POD30 and POD90.

RESULTS

The ALT values at POD5 were lower in the PC group (n = 27) 74 (48 -98) IU/L compared to PRO (n = 26) and SEV (n = 67) respectively 110 (75 -152) and 100 (64 -168) IU/L (p = 0.038). The variation of factor V compared to preoperative values was less important in the PC and SEV groups respectively -14% and -16% vs -30% (PRO) (p = 0.047).

CONCLUSION

Our study suggests that sevoflurane attenuates ischemia-reperfusion injuries on liver function, compared to propofol, without benefit for a specific regimen of pharmacological preconditioning when IPC is applied.

The Importance of Liver-Fatty Acid Binding Protein in Diagnosis of Liver Damage in Patients with Acute Hepatitis

INTRODUCTION

Acute hepatitis is acute inflammation of liver elicited by a large number of causes. It sometimes spontaneously recovers, sometimes may progress to chronic hepatitis. Liver- Fatty Acid Binding Protein (L-FABP) is a small protein that is abundant in hepatocytes, and which binds most of the long-chain fatty acids present in the cytosol.

AIM

The present study was aimed to investigate the levels of serum and urine L-FABP in acute hepatitis and diagnostic value of serum and urine L-FABP levels in patients with acute hepatitis.

MATERIALS AND METHODS

The present study included a total of 85 patients. Total number of patients with acute hepatitis were 17 (five of acute hepatitis B, one of acute hepatitis A, two of acute hepatitis C, five of autoimmune hepatitis and four of toxic hepatitis), 19 of hepatic encephalopathy, 29 of liver cirrhosis, and 20 controls were included. Serum and urinary L-FABP levels were analyzed by the Enzyme-Linked Immunosorbent Assay (ELISA).

RESULTS

Serum L-FABP levels were 9110±3352.5, 9410±1355, 9715±2462 and 3672±982.5 ng/l in patients with acute hepatitis, hepatic encephalopathy and cirrhosis and control subjects, respectively. There were statistically significant positive correlations between serum levels of L-FABP and Aspartate Aminotransferases (AST), Alanine Aminotransferases (ALT), Creatinine (Cre) and Gamma Glutamyl Transferases (GGT) (p<0.001, p<0.001, p<0.001 and p<0.001, respectively). While the cut-off value of serum L-FABP for all of the patients was 5183 ng/l {p<0.001 and Area Under Curve (AUC) 0.985}, the sensitivity and specificity were 95.4% and 100%, respectively. Positive and negative predictive values for serum L-FABP were 100% and 87%, respectively.

CONCLUSION

Serum and urine L-FABP may be a new diagnostic marker for liver damage in patients with acute hepatitis. However, our study showed that except of aminotransferases, L-FABP should be used for diagnosis of liver damage in patients with acute hepatitis, chronic hepatitis and also cirrhosis.

Early cytokine signatures of ischemia/reperfusion injury in human orthotopic liver transplantation

BACKGROUND. Orthotopic liver transplant (OLT) is the primary therapy for end-stage liver disease and acute liver failure. However, ischemia/reperfusion injury (IRI) can severely compromise allograft survival. To understand the evolution of immune responses underlying OLT-IRI, we evaluated longitudinal cytokine expression profiles from adult OLT recipients before transplant through 1 month after transplant. METHODS. We measured the expression of 38 cytokines, chemokines, and growth factors in preoperative and postoperative recipient circulating systemic blood (before transplant and 1 day, 1 week, and 1 month after transplant) and intraoperative portal blood (before and after reperfusion) of 53 OLT patients and analyzed this expression in relation to biopsy-proven IRI (n = 26 IRI+; 27 IRI-), clinical liver function tests early (days 1-7) after transplant, and expression of genes encoding cytokine receptors in biopsies of donor allograft taken before and after reperfusion. RESULTS. Bilirubin and arginine transaminase levels early after transplant correlated with IRI. Fourteen cytokines were significantly increased in the systemic and/or portal blood of IRI+ recipients that shifted from innate to adaptive-immune responses over time. Additionally, expression of cognate receptors for 10 of these cytokines was detected in donor organ biopsies by RNAseq. CONCLUSION. These results provide a mechanistic roadmap of the early immunological events both before and after IRI and suggest several candidates for patient stratification, monitoring, and treatment. FUNDING. Ruth L. Kirschstein National Research Service Award T32CA009120, Keck Foundation award 986722, and a Quantitative & Computational Biosciences Collaboratory Postdoctoral Fellowship.

Liver resection for cancer: New developments in prediction, prevention and management of postresectional liver failure

Hepatic failure is a feared complication that accounts for up to 75% of mortality after extensive liver resection. Despite improved perioperative care, the increasing complexity and extensiveness of surgical interventions, in combination with an expanding number of resections in patients with compromised liver function, still results in an incidence of postresectional liver failure (PLF) of 1-9%. Preventive measures aim to enhance future remnant liver size and function. Numerous non-invasive techniques to assess liver function and predict remnant liver volume are being developed, along with introduction of novel surgical strategies that augment growth of the future remnant liver. Detection of PLF is often too late and treatment is primarily symptomatic. Current therapeutic research focuses on ([bio]artificial) liver function support and regenerative medicine. In this review we discuss the current state and new developments in prediction, prevention and management of PLF, in light of novel insights into the aetiology of this complex syndrome.

LAY SUMMARY

Liver failure is the main cause of death after partial liver resection for cancer, and is presumably caused by an insufficient quantity and function of the liver remnant. Detection of liver failure is often too late, and current treatment focuses on relieve of symptoms. New research initiatives explore artificial support of liver function and stimulation of regrowth of the remnant liver.

Liver Fatty Acid Binding Protein Deficiency Provokes Oxidative Stress, Inflammation, and Apoptosis-Mediated Hepatotoxicity Induced by Pyrazinamide in Zebrafish Larvae

Pyrazinamide (PZA) is an essential antitubercular drug, but little is still known about its hepatotoxicity potential. This study examined the effects of PZA exposure on zebrafish (Danio rerio) larvae and the mechanisms underlying its hepatotoxicity. A transgenic line of zebrafish larvae that expressed enhanced green fluorescent protein (EGFP) in the liver was incubated with 1, 2.5, and 5 mM PZA from 72 h postfertilization (hpf). Different endpoints such as mortality, morphology changes in the size and shape of the liver, histological changes, transaminase analysis and apoptosis, markers of oxidative and genetic damage, as well as the expression of certain genes were selected to evaluate PZA-induced hepatotoxicity. Our results confirm the manner of PZA dose-dependent hepatotoxicity. PZA was found to induce marked injury in zebrafish larvae, such as liver atrophy, elevations of transaminase levels, oxidative stress, and hepatocyte apoptosis. To further understand the mechanism behind PZA-induced hepatotoxicity, changes in gene expression levels in zebrafish larvae exposed to PZA for 72 h postexposure (hpe) were determined. The results of this study demonstrated that PZA decreased the expression levels of liver fatty acid binding protein (L-FABP) and its target gene, peroxisome proliferator-activated receptor α (PPAR-α), and provoked more severe oxidative stress and hepatitis via the upregulation of inflammatory cytokines such as tumor necrosis factor alpha (TNF-α) and transforming growth factor β (TGF-β). These findings suggest that L-FABP-mediated PPAR-α downregulation appears to be a hepatotoxic response resulting from zebrafish larva liver cell apoptosis, and L-FABP can be used as a biomarker for the early detection of PZA-induced liver damage in zebrafish larvae.

Postoperative peak transaminases correlate with morbidity and mortality after liver resection

BACKGROUND

Transaminase levels are usually measured as markers of hepatocellular injury following liver resection, but recent evidence was unclear on their clinical value. This study aimed to identify factors that determine peak postoperative transaminase levels and correlated transaminase levels to postoperative complications.

STUDY DESIGN

All liver resections performed at a single center between 2006 and 2015 were included in the analysis. Multivariate analysis was used to identify factors that determine peak ALT and AST levels and postoperative morbidity and mortality. An ALT and AST cutoff for the prediction of mortality was determined using receiver operating characteristic curves analysis.

RESULTS

A total of 539 resections were included. Clavien-Dindo grade III or higher complications, intraoperative transfusion, and operative duration were identified as determinants of peak transaminases. A peak AST cut-off value for predicting mortality was defined at 828 U/L, with an area under the curve of 0.81 (0.73-0.89). The cut-off was an independent predictor of mortality (P < 0.01) along with (intraoperative) transfusion (P < 0.01), fifty-fifty criteria (P < 0.01), and age (P < 0.01).

CONCLUSION

Postoperative transaminase levels are independent predictors of postoperative morbidity and mortality and therefore clinically relevant. Transaminase levels usually peak during the first 24 h after surgery and thus possess early prognostic power in terms of postoperative mortality.

Warm ischemia time-dependent variation in liver damage, inflammation, and function in hepatic ischemia/reperfusion injury

BACKGROUND

Hepatic ischemia/reperfusion (I/R) injury is characterized by hepatocellular damage, sterile inflammation, and compromised postoperative liver function. Generally used mouse I/R models are too severe and poorly reflect the clinical injury profile. The aim was to establish a mouse I/R model with better translatability using hepatocellular injury, liver function, and innate immune parameters as endpoints.

METHODS

Mice (C57Bl/6J) were subjected to sham surgery, 30min, or 60min of partial hepatic ischemia. Liver function was measured after 24h using intravital microscopy and spectroscopy. Innate immune activity was assessed at 6 and 24h of reperfusion using mRNA and cytokine arrays. Liver inflammation and function were profiled in two patient cohorts subjected to I/R during liver resection to validate the preclinical results.

RESULTS

In mice, plasma ALT levels and the degree of hepatic necrosis were strongly correlated. Liver function was bound by a narrow damage threshold and was severely impaired following 60min of ischemia. Severe ischemia (60min) evoked a neutrophil-dominant immune response, whereas mild ischemia (30min) triggered a monocyte-driven response. Clinical liver I/R did not compromise liver function and displayed a cytokine profile similar to the mild I/R injury model.

CONCLUSIONS

Mouse models using ≤30min of ischemia best reflect the clinical liver I/R injury profile in terms of liver function dynamics and type of immune response.

GENERAL SIGNIFICANCE

This short duration of ischemia therefore has most translational value and should be used to increase the prospects of developing effective interventions for hepatic I/R.

Correlation between liver cell necrosis and circulating alanine aminotransferase after ischaemia/reperfusion injuries in the rat liver

Circulating liver enzymes such as alanine transaminase are often used as markers of hepatocellular damage. Ischaemia/reperfusion (I/R) injury is an inevitable consequence of prolonged liver ischaemia. The aim of this study was to examine the correlation between liver enzymes and volume of liver cell necrosis after ischaemia/reperfusion injuries, using design-unbiased stereological methods. Forty-seven male Wistar rats were subjected to 1 h of partial liver ischaemia, followed by either 4 or 24 h of reperfusion. Within each group, one-third of animals were subjected to ischaemic preconditioning and one-third to ischaemic postconditioning. At the end of reperfusion, blood and liver samples were collected for analysis. The volume of necrotic liver tissue was subsequently correlated to circulating markers of I/R injury. Correlation between histological findings and circulating markers was performed using Pearson's correlation coefficient. Alanine transferase peaked after 4 h of reperfusion; however, at this time-point, only mild necrosis was observed, with a Pearson's correlation coefficient of 0.663 (P = 0.001). After 24 h of reperfusion, alanine aminotransferase was found to be highly correlated to the degree of hepatocellular necrosis R = 0.836 (P = 0.000). Furthermore, alkaline phosphatase (R = 0.806) and α-2-macroglobulin (R = 0.655) levels were also correlated with the degree of necrosis. We show for the first time that there is a close correlation between the volume of hepatocellular necrosis and alanine aminotransferase levels in a model of I/R injury. This is especially apparent after 24 h of reperfusion. Similarly, increased levels of alkaline phosphatase and α-2-macroglobulin are correlated to the volume of liver necrosis.

Maternal eNOS deficiency determines a fatty liver phenotype of the offspring in a sex dependent manner

Maternal environmental factors can impact on the phenotype of the offspring via the induction of epigenetic adaptive mechanisms. The advanced fetal programming hypothesis proposes that maternal genetic variants may influence the offspring's phenotype indirectly via epigenetic modification, despite the absence of a primary genetic defect. To test this hypothesis, heterozygous female eNOS knockout mice and wild type mice were bred with male wild type mice. We then assessed the impact of maternal eNOS deficiency on the liver phenotype of wild type offspring. Birth weight of male wild type offspring born to female heterozygous eNOS knockout mice was reduced compared to offspring of wild type mice. Moreover, the offspring displayed a sex specific liver phenotype, with an increased liver weight, due to steatosis. This was accompanied by sex specific differences in expression and DNA methylation of distinct genes. Liver global DNA methylation was significantly enhanced in both male and female offspring. Also, hepatic parameters of carbohydrate metabolism were reduced in male and female offspring. In addition, male mice displayed reductions in various amino acids in the liver. Maternal genetic alterations, such as partial deletion of the eNOS gene, can affect liver metabolism of wild type offspring without transmission of the intrinsic defect. This occurs in a sex specific way, with more detrimental effects in females. This finding demonstrates that a maternal genetic defect can epigenetically alter the phenotype of the offspring, without inheritance of the defect itself. Importantly, these acquired epigenetic phenotypic changes can persist into adulthood.

Analysis of ischemia/reperfusion injury in time-zero biopsies predicts liver allograft outcomes

Ischemia/reperfusion injury (IRI) that develops after liver implantation may prejudice long-term graft survival, but it remains poorly understood. Here we correlate the severity of IRIs that were determined by histological grading of time-zero biopsies sampled after graft revascularization with patient and graft outcomes. Time-zero biopsies of 476 liver transplants performed at our center between 2000 and 2010 were graded as follows: nil (10.5%), mild (58.8%), moderate (26.1%), and severe (4.6%). Severe IRI was associated with donor age, donation after circulatory death, prolonged cold ischemia time, and liver steatosis, but it was also associated with increased rates of primary nonfunction (9.1%) and retransplantation within 90 days (22.7%). Longer term outcomes in the severe IRI group were also poor, with 1-year graft and patient survival rates of only 55% and 68%, respectively (cf. 90% and 93% for the remainder). Severe IRI on the time-zero biopsy was, in a multivariate analysis, an independent determinant of 1-year graft survival and was a better predictor of 1-year graft loss than liver steatosis, early graft dysfunction syndrome, and high first-week alanine aminotransferase with a positive predictive value of 45%. Time-zero biopsies predict adverse clinical outcomes after liver transplantation, and severe IRI upon biopsy signals the likely need for early retransplantation.