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.

Combination of risk alleles of PNPLA3, TM6SF2, and HSD17B13 of donors can predict recurrence of steatotic liver disease after liver transplantation.

AIMS: This study aimed to identify the genetic risk factors from donors or recipients that contribute to postliver transplantation (LT) steatotic liver disease (SLD), focusing on the genetic risk score (GRS) based on single nucleotide polymorphisms (SNPs) in SLD patients. METHODS: This retrospective study included 55 Japanese SLD recipients and their respective donors. Genotyping of PNPLA3, TM6SF2, and HSD17B13 was undertaken, and the combined GRS was calculated. The relationship between the GRS and the incidence of posttransplant SLD was also evaluated. RESULTS: The SLD recipients had a high prevalence of post-LT graft steatosis/steatohepatitis (76.4% and 58.2%, respectively). Although the recipients had a high frequency of risk alleles, there was no relationship between the number of risk alleles for each SNP and the incidence of posttransplant SLD. In contrast, an increased number of risk alleles for any SNP in the donor was correlated with high incidence rates of both post-LT steatosis and steatohepatitis. A multivariable analysis showed that a high donor GRS was an independent risk factor for graft steatosis (odds ratio 8.77; 95% CI, 1.94-52.94; p = 0.009). Similarly, a high donor GRS was an independent risk factor (odds ratio 6.76; 95% CI, 1.84-30.78; p = 0.007) for post-LT graft steatohepatitis. CONCLUSIONS: Donor risk alleles of PNPLA3, TM6SF2, and HSD17B13, rather than recipient risk alleles, have been implicated in the development of posttransplant SLD. The combination of these donor risk alleles into a GRS could predict the development of posttransplant SLD.

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.

Impact of the Intermittent Pringle Maneuver for Predicting Post-hepatectomy Liver Failure: A Cohort Study of 597 Consecutive Patients.

BACKGROUND: Intermittent Pringle maneuver (PM) is widely performed to reduce blood loss during hepatectomy; however, its impact on clinically relevant post-hepatectomy liver failure (PHLF) remains controversial. This study aimed to assess the impact of PM on PHLF and explore whether PM provides additional value for predicting PHLF. METHODS: Consecutive patients, who underwent hepatectomy without biliary and/or vascular reconstruction between 2011 and 2018 in a single institution, were retrospectively analyzed. The main outcome was PHLF grades B/C as defined by the International Study Group of Liver Surgery. A multivariable logistic regression model of variables significantly associated with PHLF was established. The model's predictive ability was assessed by the area under the receiver operating characteristic curve (AUROC). RESULTS: Among 597 patients, PHLF occurred in 42 (7.0%). PM was applied in 421 patients (70.5%) and was associated with the development of PHLF (PM vs. no-PM: 9.7 vs. 0.6%, P < 0.001). After the propensity score matching, patients with PM experienced significantly increased rates of PHLF (P = 0.010). Rem-ALPlat index (including future liver remnant, preoperative albumin level, and platelet count; P < 0.001), the number of PMs (P = 0.032), and blood loss (P = 0.007) were identified as significant predictors of PHLF. The model's AUROC combined with the intraoperative variables was higher than that of the preoperative model alone (0.877 vs. 0.789, P = 0.004). CONCLUSIONS: PM was involved in the occurrence of clinically relevant PHLF. Further, intraoperative factors including PM may provide additional value to predict PHLF and may facilitate early post-hepatectomy intervention.

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.

Nondegradable Collagen Increases Liver Fibrosis but Not Hepatocellular Carcinoma in Mice.

Although hepatocellular cancer (HCC) usually occurs in the setting of liver fibrosis, the causal relationship between liver fibrosis and HCC is unclear. in vivo and in vitro models of HCC involving Colr/r mice (that produce a collagenase-resistant type I collagen) or wild-type (WT) mice were used to assess the relationship between type I collagen, liver fibrosis, and experimental HCC. HCC was either chemically induced in WT and Colr/r mice or Hepa 1-6 cells were engrafted into WT and Colr/r livers. The effect of hepatic stellate cells (HSCs) from WT and Colr/r mice on the growth of Hepa 1-6 cells was studied by using multicellular tumor spheroids and xenografts. Collagen type I deposition and fibrosis were increased in Colr/r mice, but they developed fewer and smaller tumors. Hepa 1-6 cells had reduced tumor growth in the livers of Colr/r mice. Although Colr/r HSCs exhibited a more activated phenotype, Hepa 1-6 growth and malignancy were suppressed in multicellular tumor spheroids and in xenografts containing Colr/r HSCs. Treatment with vitronectin, which mimics the presence of degraded collagen fragments, converted the Colr/r phenotype into a WT phenotype. Although Colr/r mice have increased liver fibrosis, they exhibited decreased HCC in several models. Thus, increased liver type I collagen does not produce increased experimental HCC.

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.

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.

Novel mouse model for cholestasis-induced liver fibrosis resolution by cholecystojejunostomy.

BACKGROUND AND AIM: Studies on the resolution of liver fibrosis are becoming more important in this era of etiologic eradication. In contrast to the extensive research on the recovery of liver fibrosis induced by hepatotoxic injuries, regression of cholestatic liver fibrosis has been insufficiently examined owing to the limited availability of animal models. METHODS: We examined our novel recanalization mice model of biliary obstruction, involving anastomosis between the gallbladder and jejunum (G-J anastomosis) by invagination. Transgenic mice expressing green fluorescent protein (GFP) under the collagen 1(α)1 promoter underwent G-J anastomosis 14 days after bile duct ligation (BDL) and were sacrificed 14 days later. RESULTS: Transaminase and total bilirubin levels decreased to almost normal values on day 14 after G-J anastomosis. G-J anastomosis resulted in dramatic reversal of liver fibrosis induced by BDL. Activated portal fibroblasts (PFs) double-positive for GFP and Thy-1 on immunofluorescence in the liver of BDL-injured mice became less noticeable following G-J anastomosis. Messenger RNA expression of markers for activated PFs in the liver was downregulated after anastomosis. Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) were induced by BDL. After anastomosis, expressions of MMP-3, 8 as well as hepatocyte growth factor were further upregulated, whereas those of TIMP-1 and TIMP-3 were markedly downregulated. CONCLUSIONS: Our established G-J anastomosis model is associated with fibrosis resolution and reduced PF activation through reopening of bile duct obstruction and will be valuable for studying the recovery process of cholestatic liver fibrosis.

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.

Long-term impact and clinical significance of living donor liver transplantation with respect to donor liver restoration and spleen size: A prospective study.

This study aimed to evaluate postoperative long-term liver restoration and splenic enlargement and their clinical significance in living donor liver transplantation. One hundred and sixteen donors who had donated livers more than 5 years previously accepted the invitation to participate in this study. The liver restoration rate and the splenic enlargement rate were calculated as the rate with respect to the original volume. The mean liver restoration rate was 0.99 ± 0.12 and older age was associated with a higher incidence for liver restoration rate <0.95 (P = .005), whereas type of donor operation was not. The donors with liver restoration rate <0.95 showed lower serum albumin levels than those with liver restoration rate ≥0.95. The mean splenic enlargement rate was 1.10 ± 0.16. Right lobe donors demonstrated higher splenic enlargement rate (1.14 ± 0.18) than left lobe/lateral segment donors (1.06 ± 0.13). In the donors with splenic enlargement rate ≥1.10, platelet count was not fully restored to the preoperative level. In conclusion, older age increases the risk for incomplete postoperative liver restoration, which may be associated with a decrease in albumin more than 5 years after donation. Right lobe donation poses a risk of splenic enlargement, which is associated with incomplete restoration of platelet count.

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.).