Dual hypothermic oxygenated machine perfusion of the liver reduces post transplant biliary complications - a retrospective cohort study.

BACKGROUND: Corroborating evidence for use of hypothermic oxygenated machine perfusion (HOPE) prior to orthotopic liver transplantation (OLT) suggests a beneficial effect in regards to biliary complications. Here, we aim to evaluate whether perfusion via portal vein alone (sHOPE) or via additional perfusion of the hepatic artery (dHOPE) have diverging impact on outcomes after OLT when compared to use of static cold storage (SCS). METHODS: Consecutive patients undergoing OLT at Medical University of Vienna (2018 to 2023) were retrospectively analyzed. Donor organs were procured using SCS, or subjected to end-ischemic sHOPE or dHOPE. Severity of biliary complications was classified according to degree of therapeutic intervention (endoscopic retrograde cholangiopancreatography or surgical revision). RESULTS: 247 patients were included (69 SCS, 76 sHOPE, 102 dHOPE). Hospitalization was shorter for patients after HOPE (median in days: SCS=25 vs HOPE=20, P=0.019). Biliary complications were less frequent in patients after HOPE (SCS=37.7% vs HOPE=22.5%, P=0.015). A significantly lower incidence of surgical revisions for biliary complications was observed in the HOPE cohort (24.6% vs 11.8%, P=0.012). When evaluating outcome according to HOPE-modality, a significant reduction in biliary complications (P=0.006) and surgical revisions (P=0.002) was only observed in dHOPE patients in comparison to SCS. Further, only dHOPE was significantly associated with reduced need for surgical revision for biliary complications upon uni- and multivariable logistic regression (odds ratio=0.336, P=0.011). CONCLUSION: HOPE leads to a reduction of biliary complications and associated surgical revisions. This effect seems to be primarily associated with use of dHOPE, while both methods appear as feasible options for preconditioning of donor grafts prior to OLT.

SILAC-Based Characterization of Plasma-Derived Extracellular Vesicles in Patients Undergoing Partial Hepatectomy.

Post-hepatectomy liver failure (PHLF) remains a significant risk for patients undergoing partial hepatectomy (PHx). Reliable prognostic markers and treatments to enhance liver regeneration are lacking. Plasma nanoparticles, including lipoproteins, exosomes, and extracellular vesicles (EVs), can reflect systemic and tissue-wide proteostasis and stress, potentially aiding liver regeneration. However, their role in PHLF is still unknown. METHODS: Our study included nine patients with hepatocellular carcinoma (HCC) undergoing PHx: three patients with PHLF, three patients undergoing the associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) procedure, and three matched controls without complications after PHx. Patient plasma was collected before PHx as well as 1 and 5 days after. EVs were isolated by ultracentrifugation, and extracted proteins were subjected to quantitative mass spectrometry using a super-SILAC mix prepared from primary and cancer cell lines. RESULTS: We identified 2625 and quantified 2570 proteins in the EVs of PHx patients. Among these, 53 proteins were significantly upregulated and 32 were downregulated in patients with PHLF compared to those without PHLF. Furthermore, 110 proteins were upregulated and 78 were downregulated in PHLF patients compared to those undergoing ALPPS. The EV proteomic signature in PHLF indicates significant disruptions in protein translation, proteostasis, and intracellular vesicle biogenesis, as well as alterations in proteins involved in extracellular matrix (ECM) remodelling and the metabolic and cell cycle pathways, already present before PHx. CONCLUSIONS: Longitudinal proteomic analysis of the EVs circulating in the plasma of human patients undergoing PHx uncovers proteomic signatures associated with PHLF, which reflect dying hepatocytes and endothelial cells and were already present before PHx.

HMGB1-Mediated Cell Death-A Crucial Element in Post-Hepatectomy Liver Failure.

Liver resection (LR) is the primary treatment for hepatic tumors, yet posthepatectomy liver failure (PHLF) remains a significant concern. While the precise etiology of PHLF remains elusive, dysregulated inflammatory processes are pivotal. Therefore, we explored the theragnostic potential of extracellular high-mobility-group-box protein 1 (HMGB1), a key damage-associated molecular pattern (DAMP) released by hepatocytes, in liver recovery post LR in patients and animal models. Plasma from 96 LR patients and liver tissues from a subset of 24 LR patients were analyzed for HMGB1 levels, and associations with PHLF and liver injury markers were assessed. In a murine LR model, the HMGB1 inhibitor glycyrrhizin, was administered to assess its impact on liver regeneration. Furthermore, plasma levels of keratin-18 (K18) and cleaved cytokeratin-18 (ccK18) were quantified to assess suitability as predictive biomarkers for PHLF. Patients experiencing PHLF exhibited elevated levels of intrahepatic and circulating HMGB1, correlating with markers of liver injury. In a murine LR model, inhibition of HMGB1 improved liver function, reduced steatosis, enhanced regeneration and decreased hepatic cell death. Elevated levels of hepatic cell death markers K18 and ccK18 were detected in patients with PHLF and correlations with levels of circulating HMGB1 was observed. Our study underscores the therapeutic and predictive potential of HMGB1 in PHLF mitigation. Elevated HMGB1, K18, and ccK18 levels correlate with patient outcomes, highlighting their predictive significance. Targeting HMGB1 enhances liver regeneration in murine LR models, emphasizing its role in potential intervention and prediction strategies for liver surgery.

Immunosuppressive Induction Therapy Using the Antithymocyteglobulin Grafalon: A Single-Center Non-Interventional Study.

Background: Induction therapy with depleting antibodies in the setting of liver transplantation (LT) is discussed controversially to this day. The rabbit antithymocyteglobulin (ATG) Thymoglobulin (rATG) was introduced as early as 1984 and was frequently used as a standard regime for induction therapy after LT. There are no public reports characterizing Grafalon (ATG-F), a novel ATG, as an induction agent after LT. Objectives: The aim of this observational non-interventional study was to investigate the safety and efficacy of Grafalon induction therapy and characterize its clinical effects in the setting of LT. Methods: A cohort of 80 patients undergoing deceased donor LT at the Medical University of Vienna and receiving Grafalon as part of the clinical standard immunosuppressive regimen was prospectively included between March 2021 and November 2022. Patients were monitored closely for leukocytopenia and thrombocytopenia during the first postoperative week and followed up for incidence and severity of biopsy-proven acute rejection (BPAR), overall survival, and bacterial infections in the first year after LT. Results: The incidences of thrombocytopenia and leukocytopenia following Grafalon treatment peaked on postoperative day four, with 64% and 31%, respectively. However, there were no cases of severe leukocytopenia after the first postoperative week. Induction therapy with Grafalon resulted in a rate of localized bacterial infections and bacteremia of 28% and 21%, respectively. The rate of BPAR was 12.5% in the first year after LT; the one-year survival rate in this cohort was 90%. Conclusions: Overall, this study provides evidence of the safety and efficacy of Grafalon as an induction agent. Further studies investigating the potential long-term effects of Grafalon, as well as comparison studies with different immunosuppressive regimens, are needed in order to draw further conclusions.

Von Willebrand Factor Antigen Improves Risk Stratification for Patients with a Diagnosis of Resectable Hepatocellular Carcinoma.

BACKGROUND: Posthepatectomy liver failure (PHLF), complications of portal hypertension, and disease recurrence determine the outcome for hepatocellular carcinoma (HCC) patients undergoing liver resection. This study aimed to evaluate the von Willebrand factor antigen (vWF-Ag) as a non-invasive test for clinically significant portal hypertension (CSPH) and a predictive biomarker for time to recurrence (TTR) and overall survival (OS). METHODS: The study recruited 72 HCC patients with detailed preoperative workup from a prospective trial (NCT02118545) and followed for complications, TTR, and OS. Additionally, 163 compensated patients with resectable HCC were recruited to evaluate vWF-Ag cutoffs for ruling out or ruling in CSPH. Finally, vWF-Ag cutoffs were prospectively evaluated in an external validation cohort of 34 HCC patients undergoing liver resection. RESULTS: In receiver operating characteristic (ROC) analyses, vWF-Ag (area under the curve [AUC], 0.828) was similarly predictive of PHLF as indocyanine green clearance (disappearance rate: AUC, 0.880; retention rate: AUC, 0.894), whereas computation of future liver remnant was inferior (AUC, 0.756). Cox-regression showed an association of vWF-Ag with TTR (per 10%: hazard ratio [HR], 1.056; 95% confidence interval [CI] 1.017-1.097) and OS (per 10%: HR, 1.067; 95% CI 1.022-1.113). In the analyses, VWF-Ag yielded an AUC of 0.824 for diagnosing CSPH, with a vWF-Ag of 182% or lower ruling out and higher than 291% ruling in CSPH. Therefore, a highest-risk group (> 291%, 9.7% of patients) with a 57.1% incidence of PHLF was identified, whereas no patient with a vWF-Ag of 182% or lower (52.7%) experienced PHLF. The predictive value of vWF-Ag for PHLF and OS was externally validated. CONCLUSION: For patients with resectable HCC, VWF-Ag allows for simplified preoperative risk stratification. Patients with vWF-Ag levels higher than 291% might be considered for alternative treatments, whereas vWF-Ag levels of 182% or lower identify patients best suited for surgery.

Endosonographic monitoring of Sphinkeeper® prostheses movements: does physical activity have an impact?

The Sphinkeeper® procedure for treating faecal incontinence (FI) may be associated with potential implant migration (IM) and dislocation (ID), with considerable variations regarding their occurrence and effects on consecutive functional outcome. This study assessed IM and ID following the Sphinkeeper® procedure and its correlation with physical activity. This was a prospective observational clinical study of ten patients undergoing Sphinkeeper® operation due to FI between August 2020 and November 2020 at the Medical University of Vienna. Patients were followed-up after 1, 2, 3 and 6 months and 1 year postoperatively. Each follow-up visit included endosonographic monitoring of protheses location and manometric examinations. Additionally, functional outcome and physical activity were assessed using validated standardized questionnaires. The median number of prostheses implanted was 10 (IQR 9-10). The St. Mark's incontinence (SMS) score improved significantly until the last follow-up (p = 0.049), without observing a significant effect on the physical SF-12 score. The median rate of implants leading to IM and ID was 3 (range 1-4) and 2 (range 1-2) after 3 months of follow-up. A strong association of deltaSMS with number of dislocated prostheses at one month after Sphinkeeper® implantation was observed (r = 0.654, p = 0.078). Physical activity, assessed by the international physical activity questionnaire, did not have an impact on the correct prosthesis placement (1 month: p = 0.527; 2 months: p = 0.886; 3 months: p = 0.180; 6 months: p = 0.111). IM and ID of Sphinkeeper® prostheses occurred frequently early after surgery and affected functional outcome negatively. Physical activity did not have an influence on the implants displacement.

Intrahepatic neutrophil accumulation and extracellular trap formation are associated with posthepatectomy liver failure.

BACKGROUND: Posthepatectomy liver failure (PHLF) represents a life-threatening complication with limited therapeutic options. Neutrophils play a critical and dynamic role during regeneratory processes, but their role in human liver regeneration is incompletely understood, especially as underlying liver disease, detectable in the majority of patients, critically affects hepatic regeneration. Here we explored intrahepatic neutrophil accumulation and neutrophil extracellular traps (NETs) in patients with PHLF and validated the functional relevance of NETs in a murine partial hepatectomy (PHx) model. METHODS: We investigated the influx of neutrophils, macrophages, eosinophils, and mast cells and the presence of their respective extracellular traps in liver biopsies of 35 patients undergoing hepatectomy (10 patients with PHLF) before and after the initiation of liver regeneration by fluorescence microscopy. In addition, NET formation and neutrophil activation were confirmed by plasma analysis of 99 patients (24 patients with PHLF) before and up to 5 days after surgery. Furthermore, we inhibited NETs via DNase I in a murine PHx model of mice with metabolically induced liver disease. RESULTS: We detected rapid intrahepatic neutrophil accumulation, elevated levels of myeloperoxidase release, and NET formation in regenerating human livers, with a significantly higher increase of infiltrating neutrophils and NETs in patients with PHLF. Circulating markers of neutrophil activation, including elastase, myeloperoxidase, and citrullinated histone H3, correlated with markers of liver injury. In a murine PHx model, we showed that the inhibition of NET accelerated hepatocyte proliferation and liver regeneration. CONCLUSIONS: Patients with PHLF showed accelerated intrahepatic neutrophil infiltration and NET formation, which were associated with liver damage. Further, we identified postsurgical myeloperoxidase levels as predictive markers for adverse outcomes and observed that blocking NETs in a murine PHx model accelerated tissue regeneration.

Long-term outcome after SphinKeeper® surgery for treating fecal incontinence-who are good candidates?

PURPOSE: The efficacy of the novel SphinKeeper® procedure for the treatment of fecal incontinence (FI) is not yet well defined. This study aimed to assess long-term functional outcomes after SphinKeeper® surgery. METHODS: We included 32 patients with FI (28 female), who were operated at a tertiary referral center between August 2018 and September 2021. Functional outcome and quality of life were evaluated prospectively using validated questionnaires before and after surgery. Additionally, endoanal ultrasound and anal manometry were conducted prior and after SphinKeeper® implantation. Predictive parameters for treatment success were defined. RESULTS: The mean follow-up time was 22.62 ± 8.82 months. The St. Mark's incontinence score decreased significantly after surgery (median preoperative = 19 (IQR 17-22) versus median last follow-up = 12 (IQR 8-16), p = 0.001). Similarly, physical short-form health survey showed a significant improvement after SphinKeeper® implantation (p = 0.011). Patients with a higher degree of internal sphincter defect showed an improved objective therapy success (r = 0.633, p = 0.015) after SphinKeeper® operation, whereas the type and severity of FI had no impact on the functional outcome. Notably, a higher number of dislocated prostheses (r = 0.772, p = 0.015) showed a significant correlation with reduced improvement of incontinence. CONCLUSION: The SphinKeeper® procedure showed a significant long-term functional improvement in over half of the patients. Patients with a higher internal sphincter defect benefited most, whereas dislocation of the prostheses was associated with less favorable results.

An APRI+ALBI Based Multivariable Model as Preoperative Predictor for Posthepatectomy Liver Failure.

OBJECTIVE AND BACKGROUND: Clinically significant posthepatectomy liver failure (PHLF B+C) remains the main cause of mortality after major hepatic resection. This study aimed to establish an APRI+ALBI, aspartate aminotransferase to platelet ratio (APRI) combined with albumin-bilirubin grade (ALBI), based multivariable model (MVM) to predict PHLF and compare its performance to indocyanine green clearance (ICG-R15 or ICG-PDR) and albumin-ICG evaluation (ALICE). METHODS: 12,056 patients from the National Surgical Quality Improvement Program (NSQIP) database were used to generate a MVM to predict PHLF B+C. The model was determined using stepwise backwards elimination. Performance of the model was tested using receiver operating characteristic curve analysis and validated in an international cohort of 2,525 patients. In 620 patients, the APRI+ALBI MVM, trained in the NSQIP cohort, was compared with MVM's based on other liver function tests (ICG clearance, ALICE) by comparing the areas under the curve (AUC). RESULTS: A MVM including APRI+ALBI, age, sex, tumor type and extent of resection was found to predict PHLF B+C with an AUC of 0.77, with comparable performance in the validation cohort (AUC 0.74). In direct comparison with other MVM's based on more expensive and time-consuming liver function tests (ICG clearance, ALICE), the APRI+ALBI MVM demonstrated equal predictive potential for PHLF B+C. A smartphone application for calculation of the APRI+ALBI MVM was designed. CONCLUSION: Risk assessment via the APRI+ALBI MVM for PHLF B+C increases preoperative predictive accuracy and represents an universally available and cost-effective risk assessment prior to hepatectomy, facilitated by a freely available smartphone app.

Glucagon-like peptide-1 and glucagon-like peptide-2 regulation during human liver regeneration.

Accumulating evidence suggests that metabolic demands of the regenerating liver are met via lipid metabolism and critical regulators of this process. As such, glucagon-like peptide-1 (GLP-1) and glucagon-like peptide-2 (GLP-2) critically affect hepatic regeneration in rodent models. The present study aimed to evaluate potential alterations and dynamics of circulating GLP-1 and GLP-2 in patients undergoing liver resections, focusing on post-hepatectomy liver failure (PHLF). GLP-1, GLP-2, Interleukin-6 (IL-6) and parameters of lipid metabolism were determined perioperatively in fasting plasma of 46 patients, who underwent liver resection. GLP-1 and GLP-2 demonstrated a rapid and consistently inverse time course during hepatic regeneration with a significant decrease of GLP-1 and increase of GLP-2 on POD1. Importantly, these postoperative dynamics were significantly more pronounced when PHLF occurred. Of note, the extent of resection or development of complications were not associated with these alterations. IL-6 mirrored the time course of GLP-2. Assessing the main degradation protein dipeptidyl peptidase 4 (DPP4) no significant association with either GLP-1 or -2 could be found. Additionally, in PHLF distinct postoperative declines in plasma lipid parameters were present and correlated with GLP-2 dynamics. Our data suggest dynamic inverse regulation of GLP-1 and GLP-2 during liver regeneration, rather caused by an increase in expression/release than by changes in degradation capacity and might be associated with inflammatory responses. Their close association with circulating markers of lipid metabolism and insufficient hepatic regeneration after liver surgery suggest a critical involvement during these processes in humans.

Transcriptomic landscapes of effective and failed liver regeneration in humans.

Background & Aims: Although extensive experimental evidence on the process of liver regeneration exists, in humans, validation is largely missing. However, liver regeneration is critically affected by underlying liver disease. Within this project, we aimed to systematically assess early transcriptional changes during liver regeneration in humans and further assess how these processes differ in people with dysfunctional liver regeneration. Methods: Blood samples of 154 patients and intraoperative tissue samples of 46 patients undergoing liver resection were collected and classified with regard to dysfunctional postoperative liver regeneration. Of those, a matched cohort of 21 patients were used for RNA sequencing. Samples were assessed for circulating cytokines, gene expression dynamics, intrahepatic neutrophil accumulation, and spatial transcriptomics. Results: Individuals with dysfunctional liver regeneration demonstrated an aggravated transcriptional inflammatory response with higher intracellular adhesion molecule-1 induction. Increased induction of this critical leukocyte adhesion molecule was associated with increased intrahepatic neutrophil accumulation and activation upon induction of liver regeneration in individuals with dysfunctional liver regeneration. Comparing baseline gene expression profiles in individuals with and without dysfunctional liver regeneration, we found that dual-specificity phosphatase 4 (DUSP4) expression, a known critical regulator of intracellular adhesion molecule-1 expression in endothelial cells, was markedly reduced in patients with dysfunctional liver regeneration. Mimicking clinical risk factors for dysfunctional liver regeneration, we found liver sinusoidal endothelial cells of two liver disease models to have significantly reduced baseline levels of DUSP4. Conclusions: Exploring the landscape of early transcriptional changes of human liver regeneration, we observed that people with dysfunctional regeneration experience overwhelming intrahepatic inflammation. Subclinical liver disease might account for DUSP4 reduction in liver sinusoidal endothelial cells, which ultimately primes the liver for an aggravated inflammatory response. Impact and implications: Using a unique human biorepository, focused on liver regeneration (LR), we explored the landscape of circulating and tissue-level alterations associated with both functional and dysfunctional LR. In contrast to experimental animal models, people with dysfunctional LR demonstrated an aggravated transcriptional inflammatory response, higher intracellular adhesion molecule-1 (ICAM-1) induction, intrahepatic neutrophil accumulation and activation upon induction of LR. Although inflammatory responses appear rapidly after liver resection, people with dysfunctional LR have exaggerated inflammatory responses that appear to be related to decreased levels of LSEC DUSP4, challenging existing concepts of post-resectional LR.

ILC3s restrict the dissemination of intestinal bacteria to safeguard liver regeneration after surgery.

It is generally believed that environmental or cutaneous bacteria are the main origin of surgical infections. Therefore, measures to prevent postoperative infections focus on optimizing hygiene and improving asepsis and antisepsis. In a large cohort of patients with infections following major surgery, we identified that the causative bacteria are mainly of intestinal origin. Postoperative infections of intestinal origin were also found in mice undergoing partial hepatectomy. CCR6+ group 3 innate lymphoid cells (ILC3s) limited systemic bacterial spread. Such bulwark function against host invasion required the production of interleukin-22 (IL-22), which controlled the expression of antimicrobial peptides in hepatocytes, thereby limiting bacterial spread. Using genetic loss-of-function experiments and punctual depletion of ILCs, we demonstrate that the failure to restrict intestinal commensals by ILC3s results in impaired liver regeneration. Our data emphasize the importance of endogenous intestinal bacteria as a source for postoperative infection and indicate ILC3s as potential new targets.

Tyrosine phosphorylation of YAP-1 in biliary epithelial cells mediates posthepatectomy liver regeneration and is affected by serotonin.

Experimental data suggested activation of yes-associated protein (YAP-1) as a critical regulator of liver regeneration (LR). Serotonin (5-HT) promotes LR in rodent models and has been proposed to act via YAP-1. How 5-HT affects LR is incompletely understood. A possible mechanism how 5-HT affects human LR was explored. Sixty-one patients were included. Tissue samples prior and 2 h after induction of LR were collected. Circulating levels of 5-HT and osteopontin (OPN) were assessed. YAP-1, its phosphorylation states, cytokeratin 19 (CK-19) and OPN were assessed using immunofluorescence. A mouse model of biliary epithelial cells (BECs) specific deletion of YAP/TAZ was developed. YAP-1 increased as early as 2 h after induction of LR (p = 0.025) predominantly in BECs. BEC specific deletion of YAP/TAZ reduced LR after 70% partial hepatectomy in mice (Ki67%, p < 0.001). SSRI treatment, depleting intra-platelet 5-HT, abolished YAP-1 and OPN induction upon LR. Portal vein 5-HT levels correlated with intrahepatic YAP-1 expression upon LR (R = 0.703, p = 0.035). OPN colocalized with YAP-1 in BECs and its circulating levels increased in the liver vein 2 h after induction of LR (p = 0.017). In the context of LR tyrosine-phosphorylated YAP-1 significantly increased (p = 0.042). Stimulating BECs with 5-HT resulted in increased YAP-1 activation via tyrosine-phosphorylation and subsequently increased OPN expression. BECs YAP-1 appears to be critical for LR in mice and humans. Our evidence suggests that 5-HT, at least in part, exerts its pro-regenerative effects via YAP-1 tyrosine-phosphorylation in BECs and subsequent OPN-dependent paracrine immunomodulation.

The Ratio of Activin A and Follistatin-Like 3 Is Associated With Posthepatectomy Liver Failure and Morbidity in Patients Undergoing Liver Resection.

Background and Aims: Activin A is a key regulator in liver regeneration, but data evaluating its role in humans after hepatic surgery are limited. In this study we explore the predictive role of circulating activin A, its antagonist follistatin-like 3 (FSTL-3), and their ratio for posthepatectomy liver failure (PHLF) and monitor their levels after surgery, to evaluate their role in human liver regeneration. Methods: Activin A and FSTL-3 levels were assessed in 59 patients undergoing liver surgery. Using receiver operating characteristic analysis, we evaluated the predictive potential of activin A, FSTL-3, and their ratio. Results: While perioperative dynamics of activin A and FSTL3 were significantly affected by hepatic resection (activin A P = .045, FSTL-3 P = .005), their functionally relevant ratio did not significantly change (P = .528). Neither activin A nor FSTL-3 alone but only their ratio exhibited a significant predictive potential for PHLF (area under the curve: 0.789, P = .038). Patients with low preoperative activin A/FSTL-3 ratio were found to more frequently suffer from PHLF (0.017) and morbidity (0.005). Conclusion: Activin A/FSTL-3 ratio predicts PHLF and morbidity. Its significance in preoperative patient assessment needs to be further validated in larger, independent cohorts.

Hepatectomy-induced apoptotic extracellular vesicles stimulate neutrophils to secrete regenerative growth factors.

BACKGROUND & AIMS: Surgical resection of the cancerous tissue represents one of the few curative treatment options for neoplastic liver disease. Such partial hepatectomy (PHx) induces hepatocyte hyperplasia, which restores liver function. PHx is associated with bacterial translocation, leading to an immediate immune response involving neutrophils and macrophages, which are indispensable for the priming phase of liver regeneration. Additionally, PHx induces longer-lasting intrahepatic apoptosis. Herein, we investigated the effect of apoptotic extracellular vesicles (aEVs) on neutrophil function and their role in this later phase of liver regeneration. METHODS: A total of 124 patients undergoing PHx were included in this study. Blood levels of the apoptosis marker caspase-cleaved cytokeratin-18 (M30) and circulating aEVs were analyzed preoperatively and on the first and fifth postoperative days. Additionally, the in vitro effects of aEVs on the secretome, phenotype and functions of neutrophils were investigated. RESULTS: Circulating aEVs increased at the first postoperative day and were associated with higher concentrations of M30, which was only observed in patients with complete liver recovery. Efferocytosis of aEVs by neutrophils induced an activated phenotype (CD11bhighCD16highCD66bhighCD62Llow); however, classical inflammatory responses such as NETosis, respiratory burst, degranulation, or secretion of pro-inflammatory cytokines were not observed. Instead, efferocytosing neutrophils released various growth factors including fibroblast growth factor-2 and hepatocyte growth factor (HGF). Accordingly, we observed an increase of HGF-positive neutrophils after PHx and a correlation of plasma HGF with M30 levels. CONCLUSIONS: These data suggest that the clearance of PHx-induced aEVs leads to a population of non-inflammatory but regenerative neutrophils, which may support human liver regeneration. LAY SUMMARY: In this study, we show that the surgical removal of a diseased part of the liver triggers a specific type of programmed cell death in the residual liver tissue. This results in the release of vesicles from dying cells into the blood, where they are cleared by circulating immune cells. These respond by secreting hepatocyte growth factors that could potentially support the regeneration of the liver remnant.

Immunological Aspects of AXL/GAS-6 in the Context of Human Liver Regeneration.

AXL and its corresponding ligand growth arrest-specific 6 (GAS-6) are critically involved in hepatic immunomodulation and regenerative processes. Pleiotropic inhibitory effects on innate inflammatory responses might essentially involve the shift of macrophage phenotype from a pro-inflammatory M1 to an anti-inflammatory M2. We aimed to assess the relevance of the AXL/GAS-6-pathway in human liver regeneration and, consequently, its association with clinical outcome after hepatic resection. Soluble AXL (sAXL) and GAS-6 levels were analyzed at preoperative and postoperative stages in 154 patients undergoing partial hepatectomy and correlated with clinical outcome. Perioperative dynamics of interleukin (IL)-6, soluble tyrosine-protein kinase MER (sMerTK), soluble CD163 (sCD163), and cytokeratin (CK) 18 were assessed to reflect pathophysiological processes. Preoperatively elevated sAXL and GAS-6 levels predicted postoperative liver dysfunction (area under the curve = 0.721 and 0.722; P < 0.005) and worse clinical outcome. These patients failed to respond with an immediate increase of sAXL and GAS-6 upon induction of liver regeneration. Abolished AXL pathway response resulted in a restricted increase of sCD163, suggesting a disrupted phenotypical switch to regeneratory M2 macrophages. No association with sMerTK was observed. Concomitantly, a distinct association of IL-6 levels with an absent increase of AXL/GAS-6 signaling indicated pronounced postoperative inflammation. This was further supported by increased intrahepatic secondary necrosis as reflected by CK18M65. sAXL and GAS-6 represent not only potent and easily accessible preoperative biomarkers for the postoperative outcome but also AXL/GAS-6 signaling might be of critical relevance in human liver regeneration. Refractory AXL/GAS-6 signaling, due to chronic overactivation/stimulation in the context of underlying liver disease, appears to abolish their immediate release following induction of liver regeneration, causing overwhelming immune activation, presumably via intrahepatic immune regulation.

Circulating metabolites as a concept beyond tumor biology determining disease recurrence after resection of colorectal liver metastasis.

BACKGROUND: Micro-metastatic growth is considered the main source of early cancer recurrence. Nutritional and microenvironmental components are increasingly recognized to play a significant role in the liver. We explored the predictive potential of preoperative plasma metabolites for postoperative disease recurrence in colorectal cancer liver metastasis (CRCLM) patients. METHODS: All included patients (n = 71) had undergone R0 liver resection for colorectal cancer liver metastasis in the years between 2012 and 2018. Preoperative blood samples were collected and assessed for 180 metabolites using a preconfigured mass-spectrometry kit (Biocrates Absolute IDQ p180 kit). Postoperative disease-free (DFS) and overall survival (OS) were prospectively recorded. Patients that recurred within 6 months after surgery were defined as "high-risk" and, subsequently, a three-metabolite model was created which can assess DFS in our collective. RESULTS: Multiple lysophosphatidylcholines (lysoPCs) and phosphatidylcholines (PCs) significantly predicted disease recurrence within 6 months (strongest: PC aa C36:1 AUC = 0.83, p = 0.003, PC ae C34:0 AUC = 0.83, p = 0.004 and lysoPC a C18:1 AUC = 0.8, p = 0.006). High-risk patients had a median DFS of 183 days versus 522 days in low-risk population (p = 0.016, HR = 1.98 95% CI 1.16-4.35) with a 6 months recurrence rate of 47.6% versus 4.7%, outperforming routine predictors of oncological outcome. CONCLUSION: Circulating metabolites identified CRCLM patients at highest risk for 6 months disease recurrence after surgery. Our data also suggests that circulating metabolites might play a significant pathophysiological role in micro-metastatic growth and concomitant early tumor recurrences after liver resection. However, the clinical applicability and performance of this proposed metabolomic concept needs to be independently validated in future studies.

Age Related Differences in Monocyte Subsets and Cytokine Pattern during Acute COVID-19-A Prospective Observational Longitudinal Study.

The COVID-19 pandemic drastically highlighted the vulnerability of the elderly population towards viral and other infectious threats, illustrating that aging is accompanied by dysregulated immune responses currently summarized in terms like inflammaging and immunoparalysis. To gain a better understanding on the underlying mechanisms of the age-associated risk of adverse outcome in individuals experiencing a SARS-CoV-2 infection, we analyzed the impact of age on circulating monocyte phenotypes, activation markers and inflammatory cytokines including interleukin 6 (IL-6), IL-8 and tumor necrosis factor (TNF) in the context of COVID-19 disease progression and outcome in 110 patients. Our data indicate no age-associated differences in peripheral monocyte counts or subset composition. However, age and outcome are associated with differences in monocyte activation status. Moreover, a distinct cytokine pattern of IL-6, IL-8 and TNF in elderly survivors versus non-survivors, which consolidates over the time of hospitalization, suggests that older patients with adverse outcomes experience an inappropriate immune response, reminiscent of an inflammaging driven immunoparalysis. Our study underscores the value, necessity and importance of longitudinal monitoring in elderly COVID-19 patients, as dynamic changes after symptom onset can be observed, which allow for a differentiated insight into confounding factors that impact the complex pathogenesis following an infection with SARS-CoV-2.

Consequences of Perioperative Serotonin Reuptake Inhibitor Treatment During Hepatic Surgery.

BACKGROUND AND AIMS: Platelet-stored serotonin critically affects liver regeneration in mice and humans. Selective serotonin reuptake inhibitors (SSRIs) and serotonin noradrenalin reuptake inhibitors (SNRIs) reduce intraplatelet serotonin. As SSRIs/SNRIs are now one of the most commonly prescribed drugs in the United States and Europe and given serotonin's impact on liver regeneration, we evaluated whether perioperative use of SSRIs/SNRIs affects outcome after hepatic resection. APPROACH AND RESULTS: Consecutive patients undergoing hepatic resection (n = 754) were retrospectively included from prospectively maintained databases from two European institutions. Further, an independent cohort of 495 patients from the United States was assessed to validate our exploratory findings. Perioperative intake of SSRIs/SNRIs was recorded, and patients were followed up for postoperative liver dysfunction (LD), morbidity, and mortality. Perioperative intraplatelet serotonin levels were significantly decreased in patients receiving SSRI/SNRI treatment. Patients treated with SSRIs/SNRIs showed a higher incidence of morbidity, severe morbidity, LD, and LD requiring intervention. Associations were confirmed in the independent validation cohort. Combined cohorts documented a significant increase in deleterious postoperative outcome (morbidity odds ratio [OR], 1.56; 95% confidence interval [CI], 1.07-2.31; severe morbidity OR, 1.86; 95% CI, 1.22-2.79; LD OR, 1.96; 95% CI, 1.23-3.06; LD requiring intervention OR, 2.22; 95% CI, 1.03-4.36). Further, multivariable analysis confirmed the independent association of SSRIs/SNRIs with postoperative LD, which was closely associated with postoperative 90-day mortality and 1-year overall survival. CONCLUSIONS: We observed a significant association of perioperative SSRI/SNRI intake with adverse postoperative outcome after hepatic resection. This indicates that SSRIs/SNRIs should be avoided perioperatively in patients undergoing hepatic resections.

Sex differences in disease presentation, surgical and oncological outcome of liver resection for primary and metastatic liver tumors-A retrospective multicenter study.

BACKGROUND: Sex differences are becoming of rising interest in many fields of medicine. It remains unknown whether sex has a role in postoperative and long-term outcome after hepatic resection (HR). The aim of this study was to investigate sex differences in disease presentation, surgical and oncological outcome after curative HR. METHODS: Retrospective analysis of 1010 patients who underwent HR between 2005 and 2018 at two tertiary hospitals in Austria. Demographics and survival data were obtained from a prospectively maintained database. Univariate analysis was used to identify sex differences for the entire cohort and for sub-cohorts. Disease-free- and overall survival was assessed by the Kaplan-Meier estimate and results were compared by log-rank tests. RESULTS: 436 females and 574 males were analyzed. Women were younger (p<0.001), had less liver cirrhosis (p<0.001), cardiac comorbidities (p<0.001), diabetes (28 (p<0.001) and obesity (p<0.001). Type of HR and surgical management did not vary by sex. Ninety-day morbidity (p = 0.179) and -mortality (p = 0.888) were comparable. In patients with malignant disease, no differences in disease-free- and overall survival was observed, neither for the entire cohort nor for the subgroups according to tumor entity or type of resection. Only in HCC patients, females showed an inferior OS (p = 0.029). CONCLUSION: This study delivers new insights on the impact of sex differences in liver surgery. Despite the fact that male patients have a higher incidence of preoperative morbidities, we did not observe specific disparities in terms of immediate postoperative as well as long term oncological outcome between sexes.