Santol, Jonas

ABSTRACT Background and Aims Autoimmune hepatitis is an immune‐mediated liver disease characterized by chronic inflammation and progressive fibrosis. Tissue‐resident memory T cells mediate organ‐specific immunity, but their role in autoimmune hepatitis remains poorly understood. We characterized tissue‐residency‐associated T‐cell populations and their cytokine profiles, assessed associations with disease severity and determined whether these signatures were reflected in peripheral blood. Methods Paired blood and liver samples were obtained from 19 patients with autoimmune hepatitis. Comparator cohorts included 20 patients with metabolic dysfunction‐associated steatotic liver disease and 20 surgical patients providing non‐inflamed adjacent non‐tumorous liver tissue. Multiparameter flow cytometry assessed tissue‐residency markers, T‐cell differentiation and cytokine production after polyclonal stimulation. Immune phenotypes were correlated with histological and clinical parameters. Results Autoimmune hepatitis was associated with compartment‐specific remodelling of T‐cell differentiation states and intrahepatic enrichment of CD8 + T cells expressing CD69, CD103 and CXCR6 relative to paired blood and comparator liver tissues. Intrahepatic CD8 + T cells exhibited an interferon‐γ‐dominant cytokine profile, whereas CD4 + T cells showed broader interferon‐γ‐, interleukin‐17A‐ and interleukin‐4‐associated responses. Despite the enrichment of tissue‐residency‐associated CD8 + T cells, cytokine‐producing CD8 + T‐cell populations with and without a tissue‐resident memory phenotype contributed comparably to the hepatic T‐cell compartment. Tissue‐residency‐associated phenotypes correlated positively with Ishak fibrosis stage, whereas the frequency of interferon‐γ‐positive intrahepatic CD8 + T cells correlated inversely with fibrosis. Conclusions Autoimmune hepatitis was characterized by intrahepatic accumulation of phenotypically distinct and functionally active CD8 + tissue‐resident memory T cells associated with fibrosis. This immune profile was not reflected in paired blood, indicating compartmentalized hepatic immune remodelling.

Hepatic resection (HR) and liver transplantation (LT) are curative-intent treatments for hepatocellular carcinoma (HCC). Patients without cirrhosis are typically analyzed as a single group, obscuring potentially important differences between those with histologically normal liver and those with non-cirrhotic parenchymal disease. We aimed to characterize long-term outcomes following HR stratified by underlying parenchymal quality, with a contemporary LT cohort as an external benchmark. Retrospective cohort study of 662 adults undergoing curative-intent surgery for HCC at 2 tertiary centers (2010–2024). Resection patients (n=380) were stratified by non-tumor parenchymal histology into HR-Normal (n=84), HR-Diseased non-cirrhotic (n=159), and HR-Cirrhotic (n=137). A total of 282 LT recipients served as an external reference but were not entered into comparative models. Overall survival (OS) was analyzed by Kaplan–Meier and multivariable Cox regression, and recurrence by Fine–Gray competing-risks regression. Ninety-day mortality was low across resection strata (1.2%–3.2%). OS differed significantly across parenchymal groups (log-rank p =0.01), driven by superior outcomes in HR-Normal patients compared with both HR-Cirrhotic ( p =0.008) and HR-Diseased ( p =0.005). HR-Cirrhotic and HR-Diseased did not differ ( p =0.97). Five-year OS was 74.4%, 59.8% and 57.2%, respectively. On multivariable Cox regression, both cirrhosis (HR 2.03, 95% CI 1.16–3.54, p =0.01) and diseased non-cirrhotic parenchyma (HR 2.04, 95% CI 1.21–3.43, p =0.008) independently predicted death versus normal liver. Fine–Gray analysis confirmed higher recurrence risk in cirrhotic (sHR 2.09, p =0.01) and diseased non-cirrhotic (sHR 1.80, p =0.04) groups. The LT benchmark cohort achieved a 5-year OS of 82.4%. Histologically normal liver identifies a distinct HR subgroup with favorable oncologic outcomes. The conventional cirrhotic/non-cirrhotic dichotomy underestimates the prognostic impact of underlying parenchymal disease.

Abstract Gangliosides are structurally complex glycosphingolipids that regulate cellular signaling via interactions with extracellular binding partners and by influencing protein function within the membrane. Their comprehensive analysis remains analytically challenging, in part due to low endogenous abundance, extensive structural diversity, and the frequent occurrence of isomeric species arising from both glycan and ceramide moieties. Here, we present a hydrophilic interaction liquid chromatography (HILIC) nanoelectrospray ionization tandem mass spectrometry (nanoESI-MS/MS) method specifically designed to achieve isomer-resolved analysis and molecular species-level quantification of gangliosides. To improve characterization of low-abundance fatty acyl fragments, the workflow was extended by combining nanoESI with online fraction collection and subsequent direct infusion. The method demonstrated stable chromatographic performance, high sensitivity, and reproducible quantitative results across ten mouse tissues. Application of the workflow enabled quantification of 80 ganglioside molecular species belonging to 18 subclasses and revealed pronounced tissue-specific differences in subclass distribution and ceramide composition. Overall, this study establishes a robust and sensitive platform for comprehensive ganglioside analysis, providing new opportunities to investigate ganglioside diversity, regulation, and function in complex biological systems.

Abstract Carcinoid heart disease (CHD) is associated with advanced neuroendocrine tumor liver metastases (NETLM) and may preclude surgical cytoreduction. We assessed perioperative and long‐term outcomes of hepatectomy in patients with CHD. We retrospectively analyzed 311 patients undergoing cytoreductive hepatectomy for intestinal NETLM: non‐functional ( n = 163), carcinoid syndrome (CS) without CHD ( n = 110), and CHD ( n = 38), including patients undergoing pre‐hepatectomy valve replacement. CHD patients more frequently had >10 liver metastases (78%) and larger lesions (median 9.5 cm) and required major hepatectomy more often (58%). Major morbidity was higher in CHD (up to 47%), yet 90‐day mortality remained low (≤4%). Median overall survival after hepatectomy was comparable across groups (12.5 vs. 9.1 vs. 11.4 years; p = .19), including matched analyses. With optimal cardiac management, cytoreductive hepatectomy in CHD is feasible and provides long‐term survival comparable to patients without CHD.

Portal hypertension is a key factor in posthepatectomy liver failure (PHLF). While preoperative liver function tests like APRI+ALBI assess liver function, they only partially reflect portal hypertension severity. Elevated von Willebrand factor antigen (vWF-Ag) indicates endothelial dysregulation and correlates with portal hypertension. Combining vWF-Ag with APRI+ALBI may enhance PHLF prediction. A total of 534 patients who underwent liver resection at Mayo Clinic Rochester (2020–2024) were analyzed for PHLF incidence, postoperative morbidity, and 90-day mortality. Predictive probability for PHLF was assessed using receiver operating characteristic analysis and validated in an external Austrian cohort of 283 patients (2008–2017). vWF-Ag was then integrated into the existing APRI+ALBI multivariable model. PHLF grade B/C was reported in 56 patients (10.5%). The 90-day mortality rate was 0.9% (n=5). Using 2 cutoffs (182%, 240%), vWF-Ag was found to be an independent predictive factor for PHLF grade B/C that remained statistically significant upon multivariable analysis. The combination of preoperative APRI+ALBI and vWF-Ag increased the positive predictive value to 27.9% for PHLF grade B/C in the APRI+ALBI high and vWF-Ag high group. Incorporation of vWF-Ag into the established APRI+ALBI-based multivariable model revealed a superior AUC of 0.772 for PHLF risk stratification and was successfully validated in an independent cohort (AUC=0.834). The combination of vWF-Ag with APRI+ALBI demonstrates a favorable predictive potential for PHLF risk assessment. We provide 2 pathways for clinical assessment: (1) a cutoff-based system and (2) a more complex multivariable model that can be calculated in a specifically designed smartphone application.

Abstract Tumor cells develop various strategies to evade immune surveillance, one of which involves altering the metabolic state of the tumor microenvironment. In response to metabolic stress in the tumor microenvironment, several tumor-infiltrating immune subsets upregulate CD36 to take up lipids. This leads to impaired antitumor immunity, as intratumoral regulatory T cells exhibit increased survival and suppressive activity, whereas CD8+ T cells become more susceptible to ferroptosis and exhaustion. In this study, we develop a humanized anti-CD36 IgG4 antibody, PLT012, against the lipid-binding domain of CD36 with excellent safety and favorable pharmacokinetic features in mice and cynomolgus monkeys. PLT012 alone or in combination with PD-L1 blockade or standard-of-care immunotherapy results in robust antitumor immunity in both immunotherapy-sensitive and -resistant hepatocellular carcinomas (HCC). Notably, PLT012 also reprograms the immune landscape of human HCC ex vivo. Our findings provide proof-of-concept evidence that PLT012 reprograms antitumor immunity in HCC, positioning it as a first-in-class immunotherapy targeting CD36. Significance: Despite the success of cancer immunotherapies, like immune checkpoint inhibitors, many patients still fail to demonstrate significant responses because of metabolic constraints in tumors. PLT012 rejuvenates antitumor immunity by targeting metabolic pathways to reprogram the immune landscape of liver cancer and liver metastasis, with potential to influence future HCC immunotherapy.

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.

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.

Abstract Background Perioperative morbidity and mortality remain a point of concern for the Associating Liver Partition and Portal Vein Ligation for Staged hepatectomy (ALPPS) procedure. Post-hepatectomy liver failure (PHLF) after the second step poses the most significant risk factor for futile outcome. Recovery of liver function after the first step of ALPPS is critically important to allow for sufficient liver function after this surgery. The APRI+ALBI score has been proposed as an easily assessable score to monitor liver function and its dynamic recovery. Aims We explored if the APRI+ALBI score was able to assess liver function recovery after the first step of ALPPS and allow for optimal timing of the 2nd step. Methods Based on the ALPPS registry, patients from 2012 to 2020 with available APRI+ALBI score were included. Postoperative outcomes (PHLF A – C, PHLF B + C, 90-day mortality and severe morbidity) were defined as per standard definitions. The APRI/ALBI score was monitored perioperatively. Results Overall, 464 patients from 16 international participating centers in the ALPPS registry were included. Clinically relevant PHLF (B + C) was observed in 7.5 % and of these 63 % of patients ultimately died due to liver failure. The APRI+ALBI score immediately increased after each surgical intervention and continuously decrease thereafter. Failure of the APRI+ALBI score to decrease until the 2nd step of ALPPS predicted PHLF B+C (p = 0.001; AUC 0.78). Particularly patients with high APRI+ALBI scores and short interstage intervals were at risk to develop PHLF B+C. Conclusion The APRI+ALBI score objectifies liver function recovery after the 1st step of ALPPS and failure to sufficiently decreased is associated with a higher risk for PHLF B+C. This might allow for optimized planning of the 2nd step of ALPPS to allow for sufficient liver function recovery to minimize the risk for PHLF B+C and associated futile outcome.

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.