Ferroptosis-related gene glutathione peroxidase 4 promotes reprogramming of glucose metabolism via Akt-mTOR axis in intrahepatic cholangiocarcinoma.

The role of the ferroptosis-related gene glutathione peroxidase 4 (GPX4) in oncology has been extensively investigated. However, the clinical implications of GPX4 in patients with intrahepatic cholangiocarcinoma (ICC) remain unknown. This study aimed to evaluate the prognostic impact of GPX4 and its underlying molecular mechanisms in patients with ICC. Fifty-seven patients who underwent surgical resection for ICC between 2010 and 2017 were retrospectively analyzed. Based on the immunohistochemistry, patients were divided into GPX4 high (n = 15) and low (n = 42) groups, and clinical outcomes were assessed. Furthermore, the roles of GPX4 in cell proliferation, migration and gene expression were analyzed in ICC cell lines in vitro and in vivo. The results from clinical study showed that GPX4 high group showed significant associations with high SUVmax on 18F-fluorodeoxyglucose-positron emission tomography (≥8.0, P = 0.017), multiple tumors (P = 0.004), and showed glucose transporter 1 (GLUT1) high expression with a trend toward significance (P = 0.053). Overall and recurrence-free survival in the GPX4 high expression group were significantly worse than those in the GPX4 low expression group (P = 0.038 and P < 0.001, respectively). In the experimental study, inhibition of GPX4 attenuated cell proliferation and migration in ICC cell lines. Inhibition of GPX4 also decreased the expression of glucose metabolism-related genes, such as GLUT1 or HIF1α. Mechanistically, these molecular changes are regulated in Akt-mechanistic targets of rapamycin axis. In conclusion, this study suggested the pivotal value of GPX4 serving as a prognostic marker for patients with ICC. Furthermore, GPX4 can mediate glucose metabolism of ICC.

Characterization and role of collagen gene expressing hepatic cells following partial hepatectomy in mice.

BACKGROUND AND AIMS: The mechanism underlying liver regeneration following partial hepatectomy (PH) is not fully elucidated. We aimed to characterize collagen gene expressing hepatic cells following PH and examine their contribution to liver regeneration. APPROACH AND RESULTS: Col-GFP mice, which express GFP under the control of the collagen gene promoter, were used to detect collagen gene expressing cells following PH. The GFP-expressing cells were analyzed via single-cell RNA sequencing (scRNA-seq). Additionally, Col-ER Cre/RFP and Col-ER Cre/DTA mice were utilized to examine the cell fates and functional roles of collagen gene expressing cells in liver regeneration, respectively. The number of collagen gene expressing cells was found to be increased on day 3 and subsequently decreased on day 7 following PH. ScRNA-seq analysis of sorted collagen gene expressing cells showed that the regenerating liver was characterized by three distinct hepatic stellate cell (HSC) clusters, including one representing classic myofibroblasts. The other HSC clusters included an intermediately activated HSC cluster and a proliferating HSC cluster. Of these, the latter cluster was absent in the CCl 4 -induced liver fibrosis model. Cell fate tracing analysis using Col-ER Cre/RFP mice demonstrated that the collagen gene expressing cells escaped death during regeneration and remained in an inactivated state in the liver. Further, depletion of these cells using Col-ER Cre/DTA mice resulted in impaired liver regeneration. CONCLUSIONS: Heterogeneous HSC clusters, one of which was a unique proliferating cluster, were found to appear in the liver following PH. Collagen gene expressing cells, including HSCs, were found to promote liver regeneration.

High expression of autotaxin is associated with poor recurrence-free survival in cholangiocarcinoma.

BACKGROUND AND AIM: Autotaxin (ATX) is an extracellular lysophospholipase D that catalyzes the hydrolysis of lysophosphatidylcholine into lysophosphatidic acid (LPA). Recent accumulating evidence indicates the biological roles of ATX in malignant tumors. However, the expression and clinical implications of ATX in human cholangiocarcinoma (CCA) remain elusive. METHODS: In this study, the expression of ATX in 97 human CCA tissues was evaluated by immunohistochemistry. Serum ATX levels were determined in CCA patients (n = 26) and healthy subjects (n = 8). Autotaxin expression in cell types within the tumor microenvironment was characterized by immunofluorescence staining. RESULTS: High ATX expression in CCA tissue was significantly associated with a higher frequency of lymph node metastasis (p = 0.050). High ATX expression was correlated with shorter overall survival (p = 0.032) and recurrence-free survival (RFS) (p = 0.001) than low ATX expression. In multivariate Cox analysis, high ATX expression (p = 0.019) was an independent factor for shorter RFS. Compared with low ATX expression, high ATX expression was significantly associated with higher Ki-67-positive cell counts (p < 0.001). Serum ATX levels were significantly higher in male CCA patients than in healthy male subjects (p = 0.030). In the tumor microenvironment of CCA, ATX protein was predominantly expressed in tumor cells, cancer-associated fibroblasts, plasma cells, and biliary epithelial cells. CONCLUSIONS: Our study highlights the clinical evidence and independent prognostic value of ATX in human CCA.

Immunotherapy-based targeting of MSLN+ activated portal fibroblasts is a strategy for treatment of cholestatic liver fibrosis.

We investigated the role of mesothelin (Msln) and thymocyte differentiation antigen 1 (Thy1) in the activation of fibroblasts across multiple organs and demonstrated that Msln-/- mice are protected from cholestatic fibrosis caused by Mdr2 (multidrug resistance gene 2) deficiency, bleomycin-induced lung fibrosis, and UUO (unilateral urinary obstruction)-induced kidney fibrosis. On the contrary, Thy1-/- mice are more susceptible to fibrosis, suggesting that a Msln-Thy1 signaling complex is critical for tissue fibroblast activation. A similar mechanism was observed in human activated portal fibroblasts (aPFs). Targeting of human MSLN+ aPFs with two anti-MSLN immunotoxins killed fibroblasts engineered to express human mesothelin and reduced collagen deposition in livers of bile duct ligation (BDL)-injured mice. We provide evidence that antimesothelin-based therapy may be a strategy for treatment of parenchymal organ fibrosis.

A Conceptual Classification of Resectability for Hepatocellular Carcinoma.

BACKGROUNDS: In the era of multidisciplinary treatment strategy, resectability for hepatocellular carcinoma (HCC) should be defined. This study aimed to propose and validate a resectability classification of HCC. METHODS: We proposed following the three groups; resectable-(R), borderline resectable-(BR), and unresectable (UR)-HCCs. Resectable two groups were sub-divided according to the value of indocyanine green clearance of remnant liver (ICG-Krem) and presence of macrovascular invasion (MVI); BR-HCC was defined as resectable HCCs with MVI and/or ICG-Krem≥0.03-<0.05, and R-HCC was the remaining. Consecutive patients with HCC who underwent liver resection (LR) and non-surgical treatment(s) (i.e., UR-HCC) between 2011 and 2017 were retrospectively analyzed to validate the proposed classification. RESULTS: A total of 361 patients were enrolled in the study. Of these, R-, BR- and UR-HCC were found in 251, 46, and 64 patients, respectively. In patients with resected HCC, ICG-Krem≥0.05 was associated with decreased risk of clinically relevant posthepatectomy liver failure (p=0.013) and the presence of MVI was associated with worse overall survival (OS) (p<0.001). The 3-5-years OS rates according to the proposed classification were 80.3, and 68.3% versus 51.4, and 35.6%, in the R and BR groups, respectively (both p<0.001). Multivariate analysis showed BR-HCC was independently associated with poorer OS (p<0.001) after adjusting for known tumor prognostic factors. Meanwhile, BR-HCC was associated with benefit in terms of OS compared with UR-HCC (p<0.001). CONCLUSION: Our proposal of resectability for HCC allows for stratifying survival outcomes of HCC and may help to determine treatment strategy.

Impact of liver volumetric regeneration on survival outcomes in patients with hepatocellular carcinoma after major hepatectomy.

PURPOSE: Prognostic value of liver volumetric regeneration (LVR) in patients with hepatocellular carcinoma (HCC) who undergo major hepatectomy remains unknown. The aim of this study was to investigate the impact of LVR on long-term outcomes in these patients. METHODS: Data of 399 consecutive patients with HCC who underwent major hepatectomy between 2000 to 2018 were retrieved from a prospectively maintained institutional database. The LVR-index was defined as the relative increase in liver volume from 7 days to 3 months (RLV3m/RLV7d, where RLV3m and RLV7d is the remnant liver volume around 3 months and postoperative 7 days after surgery). The optimal cut-off value was determined using the median value of LVR-index. RESULTS: A total of 131 patients were eligible in this study. The optimal cut off value of LVR-index was 1.194. The 1-, 3-, 5- and 10-year overall survival (OS) rate of patients in the high LVR-index group were significantly better compared to those in the low LVR-index group (95.5%, 84.8%, 75.4% and 49.1% vs. 95.4%, 70.2%, 56.4%, and 19.9%, p = 0.002). Meanwhile, there was no significant difference with regards to time to recurrence between the two groups (p = 0.607). Significance of LVR-index for OS was retained after adjusting for known prognostic factors (p = 0.002). CONCLUSION: In patients with HCC undergoing major hepatectomy, LVR-index may serve as a prognostic indicator for OS.

Increased Expressions of Programmed Death Ligand 1 and Galectin 9 in Transplant Recipients Who Achieved Tolerance After Immunosuppression Withdrawal.

Programmed death 1 (PD1)/its ligand PD-L1 concomitant with T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3)/its ligand galectin 9 (Gal-9) and the forkhead box P3 (FOXP3) might be involved in tolerance after liver transplantation (LT). Liver biopsies from 38 tolerant, 19 nontolerant (including 16 samples that triggered reintroduction of immunosuppression [IS] and 19 samples after IS reintroduction), and 38 control LT patients were studied. The expressions of PD1, PD-L1, Gal-9, and FOXP3 were determined by immunohistochemical and immunofluorescence (IF) staining. The success period of IS withdrawal was calculated using Kaplan-Meier curve analysis. Tolerant and control patients exhibited higher PD-L1, Gal-9, and FOXP3 levels than nontolerant patients at the moment of triggering IS reintroduction. High expressions of PD-L1 and Gal-9 were associated with prolonged success of tolerance (83.3% versus 36.7% [P < 0.01] and 73.1% versus 42.9% [P = 0.03]). A strong correlation between PD-L1 and Gal-9 expression levels was detected (Spearman r = 0.73; P ≤ 0.001), and IF demonstrated colocalization of PD-L1 and Gal-9 in the cytoplasm of hepatocytes. In conclusion, the present study demonstrated that increased expressions of PD-L1 and Gal-9 were associated with sustained tolerance after IS withdrawal in pediatric liver transplantation.

Impact of Preoperative CEA Uptrend on Survival Outcomes in Patients with Colorectal Liver Metastasis After Hepatectomy.

BACKGROUND: Preoperative carcinoembryonic antigen (CEA) has been reported as a prognostic factor in patients with colorectal liver metastasis (CRLM) after hepatectomy. However, the impact of a preoperative "CEA uptrend" on prognosis after hepatectomy in these patients remains unknown. This study assessed the impact of CEA uptrend on prognosis in patients undergoing hepatectomy for CRLM. METHODS: Consecutive patients with CRLM who underwent hepatectomy between 2009 and 2018 were retrospectively analyzed. Patients with CRLM for whom CEA was measured both around 1 month before (CEA-1m) and within 3 days (CEA-3d) before hepatectomy were enrolled. A CEA-3d higher than both the upper limit of normal (5 ng/ml) and CEA-1m was defined as a CEA uptrend. RESULTS: Study participants comprised 212 patients with CRLM. Of these, 88 patients (41.5%) showed a CEA uptrend. CEA uptrend indicated better discriminatory ability (corrected Akaike information criteria, 733.72) and homogeneity (likelihood ratio chi-square value, 18.80) than CEA-3d or CEA-1m. Patients with CEA uptrend showed poorer overall survival than those without CEA uptrend (p < 0.001). After adjusting for known prognostic factors, the prognostic significance of CEA uptrend retained (hazard ratio 2.63, 95% confidence interval 1.63-4.26, p < 0.001). In subgroup analyses, the prognostic significance of CEA uptrend was retained irrespective of the status of RAS mutation or response to preoperative chemotherapy. CONCLUSIONS: CEA uptrend offers better prediction of survival outcomes than conventional CEA measurements in patients undergoing hepatectomy for CRLM.

Learning process of laparoscopic liver resection and postoperative outcomes: chronological analysis of single-center 15-years' experience.

BACKGROUND: Limited studies have reported the actual learning process of laparoscopic liver resection (LLR). This study aimed to chronologically evaluate our 15 years' experience of LLR. METHODS: All consecutive LLRs between 2006 to 2020 were retrospectively analyzed. The time period was divided into three groups; first (2006-2010), second (2011-2015), and third (2016-2020) period. The primary endpoint of this study was a composite of overall (Clavien-Dindo grade ≥ II) or major (grade ≥ IIIa) postoperative complications within 30 days. Using the IWATE criteria (four difficulty levels based on six indices), LLR was categorized as basic (< 7 points) and advanced (≥ 7 points) one. All analyses were performed based on the intention-to-treat principles. RESULTS: During the study period, a total of 382 LLRs were gradually performed (first period, n = 54; second period, n = 114, and third period, n = 214). Low incidences of overall and major complications were maintained (9.3, 10.5, and 7.0%, p = 0.514, and 1.9, 2.6, and 2.3%, p = 1.000). Meanwhile, pure LLRs (i.e., LLRs without hand-assisted or hybrid approach) and advanced LLRs were increasingly performed in 25 (46.3%), 71 (62.3%), and 205 (95.8%) patients (p < 0.001) and 3 (5.6%), 18 (15.8%), and 58 (27.1%) patients (p < 0.001), respectively. CONCLUSIONS: This study suggests that stepwise approach from basic to advanced procedures and use of hand-assisted or hybrid approach during the early phases for starting LLR practice may allow for maintaining low morbidity in specialized center.

Identification of Lineage-Specific Transcription Factors That Prevent Activation of Hepatic Stellate Cells and Promote Fibrosis Resolution.

BACKGROUND & AIMS: Development of liver fibrosis is associated with activation of quiescent hepatic stellate cells (HSCs) into collagen type I-producing myofibroblasts (activated HSCs). Cessation of liver injury often results in fibrosis resolution and inactivation of activated HSCs/myofibroblasts into a quiescent-like state (inactivated HSCs). We aimed to identify molecular features of phenotypes of HSCs from mice and humans. METHODS: We performed studies with LratCre, Ets1-floxed, Nf1-floxed, Pparγ-floxed, Gata6-floxed, Rag2-/-γc-/-, and C57/Bl6 (control) mice. Some mice were given carbon tetrachloride (CCl4) to induce liver fibrosis, with or without a peroxisome proliferator-activated receptor-γ (PPARγ) agonist. Livers from mice were analyzed by immunohistochemistry. Quiescent, activated, and inactivated HSCs were isolated from livers of Col1α1YFP mice and analyzed by chromatin immunoprecipitation and sequencing. Human HSCs were isolated from livers denied for transplantation. We compared changes in gene expression patterns and epigenetic modifications (histone H3 lysine 4 dimethylation and histone H3 lysine 27 acetylation) in primary mouse and human HSCs. Transcription factors were knocked down with small hairpin RNAs in mouse HSCs. RESULTS: Motif enrichment identified E26 transcription-specific transcription factors (ETS) 1, ETS2, GATA4, GATA6, interferon regulatory factor (IRF) 1, and IRF2 transcription factors as regulators of the mouse and human HSC lineage. Small hairpin RNA-knockdown of these transcription factors resulted in increased expression of genes that promote fibrogenesis and inflammation, and loss of HSC phenotype. Disruption of Gata6 or Ets1, or Nf1 or Pparγ (which are regulated by ETS1), increased the severity of CCl4-induced liver fibrosis in mice compared to control mice. Only mice with disruption of Gata6 or Pparγ had defects in fibrosis resolution after CCl4 administration was stopped, associated with persistent activation of HSCs. Administration of a PPARγ agonist accelerated regression of liver fibrosis after CCl4 administration in control mice but not in mice with disruption of Pparγ. CONCLUSIONS: Phenotypes of HSCs from humans and mice are regulated by transcription factors, including ETS1, ETS2, GATA4, GATA6, IRF1, and IRF2. Activated mouse and human HSCs can revert to a quiescent-like, inactivated phenotype. We found GATA6 and PPARγ to be required for inactivation of human HSCs and regression of liver fibrosis in mice.

Utility of Mac-2 Binding Protein Glycosylation Isomer to Evaluate Graft Status After Liver Transplantation.

Mac-2 binding protein glycosylation isomer (M2BPGi) is a novel liver fibrosis biomarker, but there are few studies on M2BPGi in liver transplantation (LT) recipients. This study aimed to evaluate the utility of M2BPGi measurement in LT recipients. We collected the clinicopathological data of 233 patients who underwent a liver biopsy at Kyoto University Hospital after LT between August 2015 and June 2019. The median values of M2BPGi in patients with METAVIR fibrosis stages F0, F1, F2, and ≥F3 were 0.61, 0.76, 1.16, and 1.47, respectively, whereas those in patients with METAVIR necroinflammatory indexes A0, A1, and ≥A2 were 0.53, 1.145, and 2.24, respectively. Spearman rank correlation test suggested that the necroinflammatory index had a stronger correlation to the M2BPGi value than the fibrosis stage. The area under the receiver operating characteristic curve of M2BPGi to predict ≥A1 was 0.75, which was significantly higher than that of any other liver fibrosis and inflammation marker. Patients with a rejection activity index (RAI) of ≥3 had a higher M2BPGi value than those with RAI ≤ 2 (P = 0.001). Patients with hepatitis C virus viremia had a higher M2BPGi value than sustained virological responders or those with other etiologies. In conclusion, the present study demonstrated that M2BPGi values are more strongly influenced by necroinflammatory activity and revealed M2BPGi, which has been thought to be a so-called fibrosis marker, as a disease activity marker in transplant recipients. M2BPGi measurement may be useful to detect early stage liver inflammation that cannot be detected by routine blood examination of LT recipients.

Laparoscopic Versus Open Liver Resection for Hepatocellular Carcinoma: A Case Controlled Study with Propensity Score Matching.

BACKGROUND: Several studies have suggested that laparoscopic liver resection (LLR) is associated with fewer postoperative complications than open liver resection (OLR) for hepatocellular carcinoma (HCC). However, this issue remains controversial since the data may have been attributable to an imbalance in patients' background. METHODS: We retrospectively analyzed 290 hepatectomies for HCC undertaken between 2011 and 2019. Liver resection difficulty was based on the 3 levels of the Institut Mutualiste Montsouris classification. Resection ratio was calculated using computed tomography volumetry. Patient characteristics were compared between the LLR and OLR groups. Propensity score matching (PSM) was adopted to adjust the imbalance between the cohorts, and the incidence of postoperative complications was compared. RESULTS: The difficulty and resection ratio were significantly lower in LLR (n = 112) than in OLR (n = 178) (difficulty grade I/II/III: 84/10/18 vs. 43/39/96, p < 0.001; resection ratio: 11.4 ± 12.7 vs. 22.7 ± 17.2%, p < 0.001). The incidence of postoperative complications (Clavien-Dindo grade III or more) was lower in LLR (2.7% vs. 21.9%, p < 0.001), which was mainly attributable to fewer incidences of ascites and pleural effusion. PSM generated 68 well-matched patients in each group. The lower incidence of postoperative complications in LLR was also maintained in the PSM cohort (2.9% vs. 16.2%, p = 0.017). On multivariate analysis, LLR was the independent predictor of postoperative complications (OR 0.184, 95% CI 0.051-0.672, p = 0.010). CONCLUSION: The present study demonstrated that a laparoscopic approach reduces the incidence of postoperative complications in liver resection for HCC.

Combination of recommender system and single-particle diagnosis for accelerated discovery of novel nitrides.

Discovery of new compounds from wide chemical space is attractive for materials researchers. However, theoretical prediction and validation experiments have not been systematically integrated. Here, we demonstrate that a new combined approach is powerful in significantly accelerating the discovery rate of new compounds, which should be useful for exploration of a wide chemical space in general. A recommender system for chemically relevant composition is constructed by machine learning of Inorganic Crystal Structure Database using chemical compositional descriptors. Synthesis and identification experiments are made at the chemical compositions with high recommendation scores by the single-particle diagnosis method. Two new compounds, La4Si3AlN9 and La26Si41N80O, and two new variants (isomorphic substitutions) of known compounds, La7Si6N15 and La4Si5N10O, are successfully discovered. Finally, density functional theory calculations are conducted for La4Si3AlN9 to confirm the energetic and dynamical stability and to reveal its atomic arrangement.

Dissimilarity measure of local structure in inorganic crystals using Wasserstein distance to search for novel phosphors.

To efficiently search for novel phosphors, we propose a dissimilarity measure of local structure using the Wasserstein distance. This simple and versatile method provides the quantitative dissimilarity of a local structure around a center ion. To calculate the Wasserstein distance, the local structures in crystals are numerically represented as a bag of interatomic distances. The Wasserstein distance is calculated for various ideal structures and local structures in known phosphors. The variation of the Wasserstein distance corresponds to the structural variation of the local structures, and the Wasserstein distance can quantitatively explain the dissimilarity of the local structures. The correlation between the Wasserstein distance and the full width at half maximum suggests that candidates for novel narrow-band phosphors can be identified by crystal structures that include local structures with small Wasserstein distances to local structures of known narrow-band phosphors. The quantitative dissimilarity using the Wasserstein distance is useful in the search of novel phosphors and expected to be applied in materials searches in other fields in which local structures play an important role.

IL-17 signaling in steatotic hepatocytes and macrophages promotes hepatocellular carcinoma in alcohol-related liver disease.

BACKGROUND & AIMS: Chronic alcohol consumption is a leading risk factor for the development of hepatocellular carcinoma (HCC), which is associated with a marked increase in hepatic expression of pro-inflammatory IL-17A and its receptor IL-17RA. METHODS: Genetic deletion and pharmacological blocking were used to characterize the role of IL-17A/IL-17RA signaling in the pathogenesis of HCC in mouse models and human specimens. RESULTS: We demonstrate that the global deletion of the Il-17ra gene suppressed HCC in alcohol-fed diethylnitrosamine-challenged Il-17ra-/- and major urinary protein-urokinase-type plasminogen activator/Il-17ra-/- mice compared with wild-type mice. When the cell-specific role of IL-17RA signaling was examined, the development of HCC was decreased in both alcohol-fed Il-17raΔMΦ and Il-17raΔHep mice devoid of IL-17RA in myeloid cells and hepatocytes, but not in Il-17raΔHSC mice (deficient in IL-17RA in hepatic stellate cells). Deletion of Il-17ra in myeloid cells ameliorated tumorigenesis via suppression of pro-tumorigenic/inflammatory and pro-fibrogenic responses in alcohol-fed Il-17raΔMΦ mice. Remarkably, despite a normal inflammatory response, alcohol-fed Il-17raΔHep mice developed the fewest tumors (compared with Il-17raΔMΦ mice), with reduced steatosis and fibrosis. Steatotic IL-17RA-deficient hepatocytes downregulated the expression of Cxcl1 and other chemokines, exhibited a striking defect in tumor necrosis factor (TNF)/TNF receptor 1-dependent caspase-2-SREBP1/2-DHCR7-mediated cholesterol synthesis, and upregulated the production of antioxidant vitamin D3. The pharmacological blocking of IL-17A/Th-17 cells using anti-IL-12/IL-23 antibodies suppressed the progression of HCC (by 70%) in alcohol-fed mice, indicating that targeting IL-17 signaling might provide novel strategies for the treatment of alcohol-induced HCC. CONCLUSIONS: Overall, IL-17A is a tumor-promoting cytokine, which critically regulates alcohol-induced hepatic steatosis, inflammation, fibrosis, and HCC. LAY SUMMARY: IL-17A is a tumor-promoting cytokine, which critically regulates inflammatory responses in macrophages (Kupffer cells and bone-marrow-derived monocytes) and cholesterol synthesis in steatotic hepatocytes in an experimental model of alcohol-induced HCC. Therefore, IL-17A may be a potential therapeutic target for patients with alcohol-induced HCC.

NADPH Oxidase 1 in Liver Macrophages Promotes Inflammation and Tumor Development in Mice.

BACKGROUND & AIMS: Although there are associations among oxidative stress, reduced nicotinamide adenine dinucleotide phosphate oxidase (NOX) activation, and hepatocellular carcinoma (HCC) development, it is not clear how NOX contributes to hepatocarcinogenesis. We studied the functions of different NOX proteins in mice after administration of a liver carcinogen. METHODS: Fourteen-day-old Nox1-/- mice, Nox4-/- mice, Nox1-/-Nox4-/- (double-knockout) mice, and wild-type (WT) C57BL/6 mice were given a single intraperitoneal injection of diethylnitrosamine (DEN) and liver tumors were examined at 9 months. We also studied the effects of DEN in mice with disruption of Nox1 specifically in hepatocytes (Nox1ΔHep), hepatic stellate cells (Nox1ΔHep), or macrophages (Nox1ΔMac). Some mice were also given injections of the NOX1-specific inhibitor ML171. To study the acute effects of DEN, 8-12-week-old mice were given a single intraperitoneal injection, and liver and serum were collected at 72 hours. Liver tissues were analyzed by histologic examination, quantitative polymerase chain reaction, and immunoblots. Hepatocytes and macrophages were isolated from WT and knockout mice and analyzed by immunoblots. RESULTS: Nox4-/- mice and WT mice developed liver tumors within 9 months after administration of DEN, whereas Nox1-/- mice developed 80% fewer tumors, which were 50% smaller than those of WT mice. Nox1ΔHep and Nox1ΔHSC mice developed liver tumors of the same number and size as WT mice, whereas Nox1ΔMac developed fewer and smaller tumors, similar to Nox1-/- mice. After DEN injection, levels of tumor necrosis factor, interleukin 6 (IL6), and phosphorylated signal transducer and activator of transcription 3 were increased in livers from WT, but not Nox1-/- or Nox1ΔMac, mice. Conditioned medium from necrotic hepatocytes induced expression of NOX1 in cultured macrophages, followed by expression of tumor necrosis factor, IL6, and other inflammatory cytokines; this medium did not induce expression of IL6 or cytokines in Nox1ΔMac macrophages. WT mice given DEN followed by ML171 developed fewer and smaller liver tumors than mice given DEN followed by vehicle. CONCLUSIONS: In mice given injections of a liver carcinogen (DEN), expression of NOX1 by macrophages promotes hepatic tumorigenesis by inducing the production of inflammatory cytokines. We propose that upon liver injury, damage-associated molecular patterns released from dying hepatocytes activate liver macrophages to produce cytokines that promote tumor development. Strategies to block NOX1 or these cytokines might be developed to slow hepatocellular carcinoma progression.

Activated hepatic stellate cells and portal fibroblasts contribute to cholestatic liver fibrosis in MDR2 knockout mice.

BACKGROUND & AIMS: Chronic liver injury often results in the activation of hepatic myofibroblasts and the development of liver fibrosis. Hepatic myofibroblasts may originate from 3 major sources: hepatic stellate cells (HSCs), portal fibroblasts (PFs), and fibrocytes, with varying contributions depending on the etiology of liver injury. Here, we assessed the composition of hepatic myofibroblasts in multidrug resistance gene 2 knockout (Mdr2-/-) mice, a genetic model that resembles primary sclerosing cholangitis in patients. METHODS: Mdr2-/- mice expressing a collagen-GFP reporter were analyzed at different ages. Hepatic non-parenchymal cells isolated from collagen-GFP Mdr2-/- mice were sorted based on collagen-GFP and vitamin A. An NADPH oxidase (NOX) 1/4 inhibitor was administrated to Mdr2-/- mice aged 12-16 weeks old to assess the therapeutic approach of targeting oxidative stress in cholestatic injury. RESULTS: Thy1+ activated PFs accounted for 26%, 51%, and 54% of collagen-GFP+ myofibroblasts in Mdr2-/- mice at 4, 8, and 16 weeks of age, respectively. The remaining collagen-GFP+ myofibroblasts were composed of activated HSCs, suggesting that PFs and HSCs are both activated in Mdr2-/- mice. Bone-marrow-derived fibrocytes minimally contributed to liver fibrosis in Mdr2-/- mice. The development of cholestatic liver fibrosis in Mdr2-/- mice was associated with early recruitment of Gr1+ myeloid cells and upregulation of pro-inflammatory cytokines (4 weeks). Administration of a NOX inhibitor to 12-week-old Mdr2-/- mice suppressed the activation of myofibroblasts and attenuated the development of cholestatic fibrosis. CONCLUSIONS: Activated PFs and activated HSCs contribute to cholestatic fibrosis in Mdr2-/- mice, and serve as targets for antifibrotic therapy. LAY SUMMARY: Activated portal fibroblasts and hepatic stellate cells, but not fibrocytes, contributed to the production of the fibrous scar in livers of Mdr2-/- mice, and these cells can serve as targets for antifibrotic therapy in cholestatic injury. Therapeutic inhibition of the enzyme NADPH oxidase (NOX) in Mdr2-/- mice reversed cholestatic fibrosis, suggesting that targeting NOXs may be an effective strategy for the treatment of cholestatic fibrosis.

Efficiency of acoustic radiation force impulse imaging for the staging of graft fibrosis after liver transplantation.

AIM: Liver biopsy is the gold standard for assessing liver fibrosis (LF) after liver transplantation (LT), but its invasiveness limits its utility. This study aimed to evaluate the usefulness of liver stiffness measurement (LSM) using acoustic radiation force impulse (ARFI) imaging to assess LF after LT. METHODS: Between September 2013 and January 2017, 278 patients who underwent liver biopsy after LT in Kyoto University Hospital (Kyoto, Japan) were prospectively enrolled. Liver stiffness measurement was carried out using ARFI imaging; its value was expressed as shear wave velocity (Vs) [m/s]. The LF was evaluated according to METAVIR score (F0-F4). The diagnostic performance of Vs for F2≤ and F3≤ was assessed and compared with that of laboratory tests using receiver operating characteristic (ROC) analysis. RESULTS: The median Vs values increased according to the progression of LF (F0, 1.18 (0.78-1.92); F1, 1.35 (0.72-3.54); F2, 1.55 (1.05-3.37); F3, 1.84 (1.41-2.97)). The Vs had the highest area under the ROC curve (AUROC) for the prediction of both F2 ≤ and F3 ≤ fibrosis (F2, 0.77; and F3, 0.85). With the cut-off value of Vs >1.31, sensitivity, specificity, positive predictive value, and negative predictive value were 89.4%, 53.3%, 37.3%, and 94.2% in predicting F2≤, respectively. Shear wave velocity diagnosed LF better than any laboratory tests regardless of the type of primary disease. CONCLUSIONS: Acoustic radiation force impulse helps to assess graft LF after LT. The high sensitivity suggested that ARFI might reduce the frequency of liver biopsies by detecting patients who are unlikely to have significant fibrosis after LT. (Unique trial no. UMIN R000028296.).

Usefulness of Mac-2 Binding Protein Glycosylation Isomer for Prediction of Posthepatectomy Liver Failure in Patients With Hepatocellular Carcinoma.

OBJECTIVE: The aim of this study was to evaluate the usefulness of the Mac-2 binding protein glycosylation isomer (M2BPGi) for the prediction of posthepatectomy liver failure (PHLF) in hepatocellular carcinoma (HCC) patients. SUMMARY BACKGROUND DATA: M2BPGi is a novel serum marker of liver fibrosis. The usefulness of M2BPGi for the prediction of PHLF has not been evaluated. METHODS: Clinicopathological data were analyzed in 138 HCC patients who underwent liver resection between August 2011 and November 2014. PHLF was evaluated according to the definition of the International Study Group of Liver Surgery. Performance of preoperative parameters in predicting PHLF was determined using receiver operating characteristic (ROC) analysis. RESULTS: Serum M2BPGi level correlated with the METAVIR fibrosis score. M2BPGi levels of hepatitis C virus (HCV)-positive patients were significantly higher than those of HCV-negative patients, even in the same fibrosis stage. PHLF ≥ Grade B developed in 19 patients (13.8%). The area under the ROC curve (AUROC) of M2BPGi for the prediction of PHLF ≥ Grade B was 0.71. In multivariate analysis, M2BPGi [odds ratio (OR): 2.08, 95% confidence interval (CI) 1.28-3.55], platelet count (OR: 0.39, 95% CI 0.18-0.80), and resection rate (OR: 2.71, 95% CI 1.46-5.40) were the significant factors associated with PHLF ≥ Grade B. The AUROC of the PHLF index defined by these factors was 0.81. Notably, in patients with HCV infection, the predictive ability of M2BPGi for PHLF (AUROC 0.85) was the best among the preoperative parameters. CONCLUSIONS: M2BPGi is a useful predictor of PHLF, especially in patients with HCV infection.