Olprinone attenuates excessive shear stress through up-regulation of endothelial nitric oxide synthase in a rat excessive hepatectomy model

Olprinone, a Selective Phosphodiesterase III Inhibitor, Has Protective Effects in a Septic Rat Model after Partial Hepatectomy and Primary Rat Hepatocyte

Olprinone (OLP) is a selective inhibitor of phosphodiesterase III and is used clinically in patients with heart failure and those undergoing cardiac surgery; however, little is known about the effects of OLP on hepatoprotection. The purpose of this study aimed to determine whether OLP has protective effects in in vivo and in vitro rat models of endotoxin-induced liver injury after hepatectomy and to clarify the mechanisms of action of OLP. In the in vivo model, rats underwent 70% partial hepatectomy and lipopolysaccharide treatment (PH/LPS). OLP administration increased survival by 85.7% and decreased tumor necrosis factor-α, C-X-C motif chemokine ligand 1, and inducible nitric oxide synthase (iNOS) mRNA expression in the livers of rats treated with PH/LPS. OLP also suppressed nuclear translocation and/or DNA binding ability of nuclear factor kappa B (NF-κB). Pathological liver damage induced by PH/LPS was alleviated and neutrophil infiltration was reduced by OLP. Primary cultured rat hepatocytes treated with the pro-inflammatory cytokine interleukin-1β (IL-1β) were used as a model of in vitro liver injury. Co-treatment with OLP inhibited dose-dependently IL-1β-stimulated iNOS induction and NF-κB activation. Our results demonstrate that OLP may partially inhibit the induction of several inflammatory mediators through the suppression of NF-κB and thus prevent liver injury induced by endotoxin after liver resection.

Melatonin attenuates monocrotaline-induced hepatic sinusoidal obstruction syndrome in rats via activation of Sirtuin-3

Melatonin possesses potent hepatoprotective properties, but it remains to be elucidated whether melatonin has a therapeutic effect on monocrotaline (MCT)-induced hepatic sinusoidal obstruction syndrome (HSOS). In this study, male Sprague Dawley rats were intraperitoneally injected with melatonin or the same volume of vehicle at 0 and 24 h after MCT intragastric administration. Next, hematoxylin-eosin staining and electron microscopy were performed to evaluate the hepatic sinusoidal injury of rats. Endothelial cell marker RECA-1 was observed by immunohistochemistry. Hepatic oxidative stress was analyzed by detecting malondialdehyde, glutathione S-transferase, and reactive oxygen species. Assessment of liver function was carried out by analysis of serum aspartate aminotransferase, alanine aminotransferase, total bilirubin, and albumin levels. Real-time polymerase chain reaction and Western blot analysis were used to identify liver Sirtuin-3 (SIRT3) and active matrix metallopeptidase 9 (MMP-9) expression. Besides, liver sinusoidal endothelial cells (LSECs) were used for the in vitro functional verification experiment. Specifically, liver histology of the melatonin-treated groups showed that the pathological damages caused by MCT were significantly attenuated, total HSOS scores were decreased, and the elevation of serum hyaluronic acid observed in the model group was also reduced. Moreover, melatonin treatment also improved the survival of rats after partial hepatectomy. Administration of melatonin ameliorated MCT-induced LSECs injury, hepatic oxidative stress, and hepatic dysfunction. Furthermore, melatonin treatment increased SIRT3 expression while attenuating MMP-9 activity in liver tissues. Cell experiment also demonstrated that SIRT3 might mediate the protective effect of melatonin on LSECs. Collectively, our study provided the potential rationale for the application of melatonin for the prevention of MCT-induced HSOS.

Cellular crosstalk during liver regeneration: unity in diversity

The liver is unique in its ability to regenerate from a wide range of injuries and diseases. Liver regeneration centers around hepatocyte proliferation and requires the coordinated actions of nonparenchymal cells, including biliary epithelial cells, liver sinusoidal endothelial cells, hepatic stellate cells and kupffer cells. Interactions among various hepatocyte and nonparenchymal cells populations constitute a sophisticated regulatory network that restores liver mass and function. In addition, there are two different ways of liver regeneration, self-replication of liver epithelial cells and transdifferentiation between liver epithelial cells. The interactions among cell populations and regenerative microenvironment in the two modes are distinct. Herein, we first review recent advances in the interactions between hepatocytes and surrounding cells and among nonparenchymal cells in the context of liver epithelial cell self-replication. Next, we discuss the crosstalk of several cell types in the context of liver epithelial transdifferentiation, which is also crucial for liver regeneration.

Se-Methylselenocysteine Alleviates Liver Injury in Diethylnitrosamine (DEN)-Induced Hepatocellular Carcinoma Rat Model by Reducing Liver Enzymes, Inhibiting Angiogenesis, and Suppressing Nitric Oxide (NO)/Nitric Oxide Synthase (NOS) Signaling Pathway

Background

Hepatocellular carcinoma is the third leading cause of cancer-associated mortality. This study aimed to investigate the effects of se-methylselenocysteine (MSC) on oncogenesis of diethylnitrosamine (DEN)-induced hepatocellular carcinoma.

Material/Methods

A hepatocellular carcinoma rat model was established by administering DEN. Rat models were divided into Model (0.1 mg/kg MSC), Model+0.3 mg/kg MSC, Model+1 mg/kg MSC, and Model+3 mg/kg MSC groups. A Normal control group consisted of mice not administered MSC. Hematoxylin and eosin staining was used to determine liver injury. Immunohistochemical analysis was conducted to identify CD34 and vascular endothelial growth factor (VEGF) expression. VEGF gene transcription was detected with RT-PCR. Biochemical analyses were performed to determine alanine aminotransferase, aspartate aminotransferase, total bilirubin, γ-glutamyl transpeptidase, alkaline phosphatase, and albumin levels in serum, and nitric oxide (NO)/nitric oxide synthase (NOS) levels in liver tissues. Transmission electron microscopy was used to observe the ultra-microstructures of hepatocytes.

Results

MSC treatment markedly alleviated liver injury and nuclear lesions in the treatment groups compared to the Model group. MSC treatment significantly improved liver functions in the treatment groups compared to the Model group (P<0.05). MSC treatment significantly decreased CD34 expression and NO and NOS levels in liver tissues and suppressed VEGF expression compared to the Model group (all P<0.05).

Conclusions

MSC administration alleviated liver injury in a DEN-induced hepatocellular carcinoma rat model through reducing liver enzymes, inhibiting angiogenesis, and suppressing the NO/NOS signaling pathway.

Critical Role of LSEC in Post-Hepatectomy Liver Regeneration and Failure

Liver sinusoids are lined by liver sinusoidal endothelial cells (LSEC), which represent approximately 15 to 20% of the liver cells, but only 3% of the total liver volume. LSEC have unique functions, such as fluid filtration, blood vessel tone modulation, blood clotting, inflammatory cell recruitment, and metabolite and hormone trafficking. Different subtypes of liver endothelial cells are also known to control liver zonation and hepatocyte function. Here, we have reviewed the origin of LSEC, the different subtypes identified in the liver, as well as their renewal during homeostasis. The liver has the exceptional ability to regenerate from small remnants. The past decades have seen increasing awareness in the role of non-parenchymal cells in liver regeneration despite not being the most represented population. While a lot of knowledge has emerged, clarification is needed regarding the role of LSEC in sensing shear stress and on their participation in the inductive phase of regeneration by priming the hepatocytes and delivering mitogenic factors. It is also unclear if bone marrow-derived LSEC participate in the proliferative phase of liver regeneration. Similarly, data are scarce as to LSEC having a role in the termination phase of the regeneration process. Here, we review what is known about the interaction between LSEC and other liver cells during the different phases of liver regeneration. We next explain extended hepatectomy and small liver transplantation, which lead to "small for size syndrome" (SFSS), a lethal liver failure. SFSS is linked to endothelial denudation, necrosis, and lobular disturbance. Using the knowledge learned from partial hepatectomy studies on LSEC, we expose several techniques that are, or could be, used to avoid the "small for size syndrome" after extended hepatectomy or small liver transplantation.

Protection of liver sinusoids by intravenous administration of human Muse cells in a rat extra-small partial liver transplantation model

Small-for-size syndrome (SFSS) has a poor prognosis due to excessive shear stress and sinusoidal microcirculatory disturbances in the acute phase after living-donor liver transplantation (LDLT). Multilineage-differentiating stress enduring (Muse) cells are reparative stem cells found in various tissues and currently under clinical trials. These cells selectively home to damaged sites via the sphingosine-1-phosphate (S1P)-S1P receptor 2 system and repair damaged tissue by pleiotropic effects, including tissue protection and damaged/apoptotic cell replacement by differentiating into tissue-constituent cells. The effects of intravenously administered human bone marrow-Muse cells and -mesenchymal stem cells (MSCs) (4 × 105 ) on liver sinusoidal endothelial cells (LSECs) were examined in a rat SFSS model without immunosuppression. Compared with MSCs, Muse cells intensively homed to the grafted liver, distributed to the sinusoids and vessels, and delivered improved blood chemistry and Ki-67(+) proliferative hepatocytes and -LSECs within 3 days. Tissue clearing and three-dimensional imaging by multiphoton laser confocal microscopy revealed maintenance of the sinusoid continuity, organization, and surface area, as well as decreased sinusoid interruption in the Muse group. Small-interfering RNA-induced knockdown of hepatocyte growth factor and vascular endothelial growth factor-A impaired the protective effect of Muse cells on LSECs. Intravenous injection of Muse cells might be a feasible approach for LDLT with less recipient burden.

Post hepatectomy liver failure - A comprehensive review of current concepts and controversies

Post hepatectomy liver failure (PHLF) comprises of a conundrum of symptoms and signs following major hepatic resections. The pathophysiology essentially revolves around disruption of the normal hepatocyte regeneration and disturbed liver homeostasis. Prompt identification of the pre-operative predictors of PHLF in the form of biochemical parameters and imaging features are of paramount importance for any hepatic surgeon and forms the cornerstone of its management. Treatment revolves around a goal-directed resuscitation of the systemic organ failure. Auxiliary support systems such as liver dialysis devices and stem cell therapy are still under investigational trials for treatment of the same. Orthotopic liver transplantation (OLT) is the last resort in most cases not responding to other measures.

Effects of splanchnic vasoconstrictors on liver regeneration and survival after 90% rat hepatectomy

Purpose

Posthepatectomy liver failure is a serious complication and considered to be caused by increased portal pressure and flow. Splanchnic vasoactive agents and propranolol are known to decrease portal pressure. The aim of this study was to identify optimal candidates with potential for clinical use among somatostatin, terlipressin, and propranolol using rats with 90% hepatectomy.

Methods

Rats were divided into 5 groups: sham operation (n = 6), control (n = 20), propranolol (n = 20), somatostatin (n = 20), and terlipressin group (n = 20). Seven-day survival rates and portal pressure change were measured, and biochemical, histologic, and molecular analyses were performed.

Results

Portal pressure was significantly decreased in all 3 treatment groups compared to control. All treatment groups showed a tendency of decreased liver injury markers, and somatostatin showed the most prominent effect at 24 hours postoperatively. Histologic liver injury at 24 hours was significantly decreased in propranolol and terlipressin groups (P = 0.016, respectively) and somatostatin group showed borderline significance (P = 0.056). Hepatocyte proliferation was significantly increased after 24 hours in all treatment groups. Median survival was significantly increased in terlipressin group compared to control group (P < 0.01).

Conclusion

Terlipressin is considered as the best candidate, while somatostatin has good potential for clinical use, considering their effects on portal pressure and subsequent decrease in liver injury and increase in liver regeneration.

Liver-specific Prox1 inactivation causes hepatic injury and glucose intolerance in mice

Previous reports have revealed that Prospero-related homeobox 1 (Prox1) is required for the migration and differentiation of hepatoblasts during embryonic liver formation. However, the role of Prox1 in adults remains to be elucidated. We created liver-specific Prox1 knockout mice to verify the role of Prox1 in adult hepatocytes. The mutant mice exhibit hepatic injury and a nonobese, insulin-resistant diabetic phenotype in vivo. Hepatocyte injury is observed predominantly in the perivenous region and is characterized by the formation of vacuoles and emergence of round-shaped mitochondria, suggesting that the effect of Prox1 on the maintenance of adult hepatocytes is region dependent. Furthermore, glycolysis is suppressed, and both oxidative phosphorylation and autophagy are upregulated in the livers of Prox1 knockout mice, indicating that Prox1 has a role in regulating energy homeostasis in hepatocytes.

Liver sinusoidal endothelial cells: Physiology and role in liver diseases

Liver sinusoidal endothelial cells (LSECs) are highly specialized endothelial cells representing the interface between blood cells on the one side and hepatocytes and hepatic stellate cells on the other side. LSECs represent a permeable barrier. Indeed, the association of 'fenestrae', absence of diaphragm and lack of basement membrane make them the most permeable endothelial cells of the mammalian body. They also have the highest endocytosis capacity of human cells. In physiological conditions, LSECs regulate hepatic vascular tone contributing to the maintenance of a low portal pressure despite the major changes in hepatic blood flow occurring during digestion. LSECs maintain hepatic stellate cell quiescence, thus inhibiting intrahepatic vasoconstriction and fibrosis development. In pathological conditions, LSECs play a key role in the initiation and progression of chronic liver diseases. Indeed, they become capillarized and lose their protective properties, and they promote angiogenesis and vasoconstriction. LSECs are implicated in liver regeneration following acute liver injury or partial hepatectomy since they renew from LSECs and/or LSEC progenitors, they sense changes in shear stress resulting from surgery, and they interact with platelets and inflammatory cells. LSECs also play a role in hepatocellular carcinoma development and progression, in ageing, and in liver lesions related to inflammation and infection. This review also presents a detailed analysis of the technical aspects relevant for LSEC analysis including the markers these cells express, the available cell lines and the transgenic mouse models. Finally, this review provides an overview of the strategies available for a specific targeting of LSECs.

Phase I clinical trial of olprinone in liver surgery

PURPOSE

Post-hepatectomy liver failure is one of the most serious complications liver surgeons must overcome. We previously examined olprinone, a selective phosphodiesterase III inhibitor, and demonstrated its hepatoprotective effects in rats and pigs. We herein report the results of a phase I clinical trial of olprinone in liver surgery (UMIN000004975).

METHODS

Twenty-three patients who underwent hepatectomy between 2011 and 2015 were prospectively registered. In the first 6 cases, olprinone (0.1 μg/kg/min) was administered for 24 h from the start of surgery. In the remaining 17 cases, olprinone (0.05 μg/kg/min) was administered from the start of surgery until just before the transection of the liver parenchyma. The primary endpoint was safety, and the secondary endpoint was efficacy. For the evaluation of efficacy, the incidence of post-hepatectomy liver failure in 20 hepatocellular carcinoma patients was externally compared with 20 propensity score-matched patients.

RESULTS

No intraoperative side effects were observed, and the morbidity rates in the analyzed cohorts were acceptable. The rate of post-hepatectomy liver failure frequency tended to be lower in the olprinone group.

CONCLUSIONS

The safety of olprinone in liver surgery was confirmed. The efficacy of olprinone will be re-evaluated in clinical trials.

Identification of Keratin 19-Positive Cancer Stem Cells Associating Human Hepatocellular Carcinoma Using 18F-Fluorodeoxyglucose Positron Emission Tomography

Purpose: The current lack of tools for easy assessment of cancer stem cells (CSC) prevents the development of therapeutic strategies for hepatocellular carcinoma (HCC). We previously reported that keratin 19 (K19) is a novel HCC-CSC marker and that PET with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) is an effective method for predicting postoperative outcome in hepatocellular carcinoma. Herein, we examined whether K19⁺ HCC-CSCs can be tracked using ¹⁸F-FDG-PET.Experimental Design: K19 and glucose transporter-1 (GLUT1) expression was evaluated by IHC in 98 hepatocellular carcinoma patients who underwent ¹⁸F-FDG-PET scans before primary tumor resection. Standardized uptake values (SUV) for primary tumors and tumor-to-nontumor SUV ratios (TNR) were calculated using FDG accumulation levels, and values were compared among K19⁺/K19^- patients. Using hepatocellular carcinoma cell lines encoding with a K19 promoter-driven enhanced GFP, ¹⁸F-FDG uptake and GLUT1 expression were examined in FACS-isolated K19⁺/K19^- cells.Results: In hepatocellular carcinoma patients, K19 expression was significantly correlated with GLUT1 expression and FDG accumulation. ROC analyses revealed that among preoperative clinical factors, TNR was the most sensitive indicator of K19 expression in hepatocellular carcinoma tumors. In hepatocellular carcinoma cells, FACS-isolated K19⁺ cells displayed significantly higher ¹⁸F-FDG uptake than K19^- cells. Moreover, gain/loss-of-function experiments confirmed that K19 regulates ¹⁸F-FDG uptake through TGFβ/Smad signaling, including Sp1 and its downstream target GLUT1.Conclusions:¹⁸F-FDG-PET can be used to predict K19 expression in hepatocellular carcinoma and should thereby aid in the development of novel therapeutic strategies targeting K19⁺ HCC-CSCs. Clin Cancer Res; 23(6); 1450-60. ©2016 AACR.

SOX9 is a novel cancer stem cell marker surrogated by osteopontin in human hepatocellular carcinoma

The current lack of cancer stem cell (CSC) markers that are easily evaluated by blood samples prevents the establishment of new therapeutic strategies in hepatocellular carcinoma (HCC). Herein, we examined whether sex determining region Y-box 9 (SOX9) represents a new CSC marker, and whether osteopontin (OPN) can be used as a surrogate marker of SOX9 in HCC. In HCC cell lines transfected with a SOX9 promoter-driven enhanced green fluorescence protein gene, FACS-isolated SOX9⁺ cells were capable of self-renewal and differentiation into SOX9⁻ cells, and displayed high proliferation capacity in vitro. Xenotransplantation experiments revealed that SOX9⁺ cells reproduced, differentiated into SOX9⁻ cells, and generated tumors at a high frequency in vivo. Moreover, SOX9⁺ cells were found to be involved in epithelial-mesenchymal transition (EMT) and activation of TGFb/Smad signaling. Gain/loss of function experiments showed that SOX9 regulates Wnt/beta-catenin signaling, including cyclin D1 and OPN. Immunohistochemistry of 166 HCC surgical specimens and serum OPN measurements showed that compared to SOX9⁻ patients, SOX9⁺ patients had significantly poorer recurrence-free survival, stronger venous invasion, and higher serum OPN levels. In conclusion, SOX9 is a novel HCC-CSC marker regulating the Wnt/beta-catenin pathway and its downstream target, OPN. OPN is a useful surrogate marker of SOX9 in HCC.

Laparoscopic splenectomy for patients with liver cirrhosis: Improvement of liver function in patients with Child-Pugh class B

BACKGROUND

We aimed to assess the short-term outcomes of laparoscopic splenectomy (LS) and liver function at 1 year after splenectomy in the patients with liver cirrhosis.

METHODS

Forty-five patients with liver cirrhosis and hypersplenism underwent LS. We reviewed electronic medical records regarding the liver functional reserve, the etiology of liver cirrhosis, and the presence of hepatocellular carcinoma and esophago-gastric varices. Prospectively collected data of perioperative variables, postoperative complications, and long-term liver function were analyzed.

RESULTS

Forty-five patients had a chronic liver disease classified into Child-Pugh classes (A/B/C: 23/20/2). The etiologies of disease were hepatitis C virus infection in 34 patients, hepatitis B virus infection in 4, and others in 7. Fourteen patients underwent procedures in addition to LS, including hepatectomy (n = 7) and devascularization for esophagogastric varices (n = 8). Postoperative complications occurred in 11 patients (24%). Neither postoperative liver failure nor in-hospital mortality occurred. White blood cell and platelet counts determined 7 days, 1 month, and 1 year after LS doubled or increased more than twice compared with the preoperative values (P < .001). One year after LS, patients who had been classified preoperatively into Child-Pugh class B had decreased total serum bilirubin levels (P = .03), and increased prothrombin activity (P = 003) and decreased Child-Pugh scores (P = .001). The Child-Pugh classifications improved in 14 of 18 patients (78%) who had Child-Pugh class B preoperatively.

CONCLUSION

LS is a safe and feasible procedure for hypersplenism in patients with liver cirrhosis. In addition, LS most likely ameliorates liver function at 1 year after LS in patients with Child-Pugh class B liver cirrhosis.

Effect of fluid shear stress on portal vein remodeling in a rat model of portal hypertension

Aims. To explore the effects and mechanisms of fluid shear stress on portal vein remodeling in a rat model of portal hypertension. Methods. Subcutaneous injections of CCl4 were given to establish a rat model of liver cirrhosis and portal hypertension. Biomechanical technology was adopted to determine the dynamic changes of haemodynamic indices and fluid shear stress. Nitric oxide (NO), synthase (NOS), and endothelin-1 (ET-1) of the portal vein blood were measured. Changes in geometric structure and ultrastructure of the portal vein were observed using optical and electron microscopy. Results. After the CC14 injections, rat haemodynamics were notably altered. From week 4 onwards, PVP, PVF, and PVR gradually and significantly increased (P < 0.05 versus baseline). The fluid shear stress declined from week 4 onwards (P < 0.01 versus control group). NO, NOS, and ET-1 increased after repeated CCI4 injections. Hematoxylin and eosin staining showed thickened portal vein walls, with increased inside and outside diameters. Electron microscopy revealed different degrees of endothelial cell degeneration, destruction of basement membrane integrity, proliferating, and hypertrophic smooth muscle cells. Conclusions. Fluid shear stress not only influenced the biomechanical environment of the portal vein but also participated in vascular remodeling.

Keratin 19, a Cancer Stem Cell Marker in Human Hepatocellular Carcinoma

PURPOSE

Keratin 19 (K19) is a known marker of poor prognosis and invasion in human hepatocellular carcinoma (HCC). However, the relationship between K19 and cancer stem cells (CSCs) is unclear. Here, we determined whether K19 can be used as a new CSC marker and therapeutic target in HCC.

EXPERIMENTAL DESIGN

HCC cell lines were transfected with a K19 promoter-driven enhanced green fluorescence protein gene. CSC characteristics, epithelial-mesenchymal transition (EMT), and TGFb/Smad signaling were examined in FACS-isolated K19(+)/K19(-) cells. K19 and TGFb receptor 1 (TGFbR1) expression in 166 consecutive human HCC surgical specimens was examined immunohistochemically.

RESULTS

FACS-isolated single K19(+) cells showed self-renewal and differentiation into K19(-) cells, whereas single K19(-) cells did not produce K19(+) cells. K19(+) cells displayed high proliferation capacity and 5-fluorouracil resistance in vitro. Xenotransplantation into immunodeficient mice revealed that K19(+) cells reproduced, differentiated into K19(-) cells, and generated large tumors at a high frequency in vivo. K19(+) cells were found to be involved in EMT and the activation of TGFb/Smad signaling, and these properties were suppressed by K19 knockdown or treatment with a TGFbR1 inhibitor. The TGFbR1 inhibitor also showed high therapeutic effect against K19(+) tumor in the mouse xenograft model. Immunohistochemistry of HCC specimens showed that compared with K19(-) patients, K19(+) patients had significantly poorer recurrence-free survival and higher tumor TGFbR1 expression.

CONCLUSIONS

K19 is a new CSC marker associated with EMT and TGFb/Smad signaling, and it would thus be a good therapeutic target for TGFbR1 inhibition.

Novel regulators of endothelial barrier function

Endothelial barrier function is an essential and tightly regulated process that ensures proper compartmentalization of the vascular and interstitial space, while allowing for the diffusive exchange of small molecules and the controlled trafficking of macromolecules and immune cells. Failure to control endothelial barrier integrity results in excessive leakage of fluid and proteins from the vasculature that can rapidly become fatal in scenarios such as sepsis or the acute respiratory distress syndrome. Here, we highlight recent advances in our understanding on the regulation of endothelial permeability, with a specific focus on the endothelial glycocalyx and endothelial scaffolds, regulatory intracellular signaling cascades, as well as triggers and mediators that either disrupt or enhance endothelial barrier integrity, and provide our perspective as to areas of seeming controversy and knowledge gaps, respectively.

Soluble thrombomodulin attenuates sinusoidal obstruction syndrome in rat through suppression of high mobility group box 1

BACKGROUND

Sinusoidal obstruction syndrome (SOS) is a drug-induced liver injury caused by anticancer treatment such as oxaliplatin-based chemotherapy in patients with hepatic colorectal metastases. SOS is also associated with postoperative morbidity after hepatectomy.

AIMS

The aim of this study was to investigate the effects of recombinant human soluble thrombomodulin (rTM) in a monocrotaline (MCT)-induced SOS model in rats.

METHODS

Rats were administered rTM by intravenous injection (3 mg/kg) and subcutaneous injection (3 mg/kg) concurrently with MCT administration. Other rats received the same volume of normal saline (NS) and MCT. Liver tissue and blood were collected 48 h after MCT administration to evaluate SOS. Survival after 30% partial hepatectomy was also investigated in both groups. Electron microscopy and immunohistochemistry were used to examine sinusoidal endothelial cells (SECs). Serum concentrations of high mobility group box 1 (HMGB1) and neutrophil accumulation were also measured.

RESULTS

In the NS group, liver histology showed SOS phenotypes. In the rTM group, these changes were suppressed, total SOS scores were significantly lower, and serum transaminase levels were significantly reduced compared with the NS group. Survival after 30% hepatectomy was significantly higher in the rTM group (57% vs. 22%, P = 0.0070). Electron microscopy and immunohistochemistry showed a protective effect of rTM on SECs. rTM also attenuated the serum HMGB1 level (9.2 vs. 19.6 ng/ml, P = 0.0086), active neutrophil recruitment and myeloperoxidase activity.

CONCLUSION

rTM preserved SECs and attenuated MCT-induced SOS in rats through suppression of circulatory HMGB1 and neutrophil accumulation, resulting in improved survival after hepatectomy.

The impact of posthepatectomy liver failure on the recurrence of hepatocellular carcinoma

BACKGROUND

Patients with hepatocellular carcinoma (HCC) who underwent hepatectomy often developed an intrahepatic recurrence, even though it was a curative one. The relationship between surgery-induced liver damage and the recurrence of HCC has not been described. This study evaluated whether posthepatectomy liver failure, as defined by the International Study Group of Liver Surgery, affected the recurrence of HCC.

METHODS

We performed a retrospective cohort study of 488 patients with HCC who underwent hepatectomy between 2004 and 2012 at Kyoto University Hospital. Early posthepatectomy liver failure (EPLF) was defined as liver failure occurring between postoperative days 5 and 10. The patients were divided into an EPLF group and a non-EPLF group. Disease-free survival (DFS) was compared between these groups. The influences of host-related, surgery-related, and tumor-related factors on patient outcomes were evaluated using multivariate analyses.

RESULTS

The EPLF group and the non-EPLF group contained 153 and 335 patients, respectively. The probability of DFS was significantly increased in the non-EPLF group (median: 574 days) compared to the EPLF group (median: 348 days) (hazard ratio, HR [95 % confidence interval, CI] 1.61 [1.29-2.00]). The multivariate analysis revealed that EPLF was an independent factor for DFS (HR [95 % CI] 1.43 [1.13-1.81]), besides the factors previously described, including fibrosis (1.32 [1.05-1.67]), stage (1.85 [1.34-2.51]), tumor differentiation (1.46 [1.11-1.89]), and des-γ-carboxyprothrombin (1.39 [1.10-1.74]).

CONCLUSIONS

EPLF was associated with postoperative HCC recurrence. The prevention of EPLF might improve the prognosis of patients with HCC.

Hepatoprotective effect by pretreatment with olprinone in a swine partial hepatectomy model

Excessive portal flow to a small remnant liver or small-for-size graft is a primary factor of small-for-size syndrome. We demonstrated that olprinone (OLP), a phosphodiesterase III inhibitor, had a hepatoprotective effect in a rat extended hepatectomy model and a small-for-size liver transplantation model through a modification of the portal venous pressure (PVP). To identify the appropriate dose and duration of treatment for clinical applications, we conducted experiments with a swine partial hepatectomy model. Twenty microminipigs were divided into 4 groups that received the following treatments: (A) saline (control group), (B) OLP at 0.3 μg/kg/minute (preoperative and postoperative administration), (C) OLP at 0.1 μg/kg/minute (preoperative administration), and (D) OLP at 0.3 μg/kg/minute (preoperative administration). The pigs underwent 70% partial hepatectomy. Hemodynamic changes, including changes in PVP, were examined. Liver biopsy was performed 1 and 3 hours after hepatectomy. Blood samples were collected until postoperative day 7 (POD7). In comparison with group A, PVP elevations, periportal edema, and sinusoidal hemorrhaging were attenuated after left Glisson's ligation in groups C and D. Pretreatment with OLP in groups C and D preserved the microstructure of sinusoids and improved the prothrombin activity 1 and 3 hours after hepatectomy. These animals showed better recovery of the remnant liver volume and the plasma disappearance rate of indocyanine green on POD7. In contrast, group B showed exacerbation of liver damage. Measurements of the serum OLP concentration showed that 10 ng/mL OLP was appropriate for a hepatoprotective effect. In conclusion, pretreatment with OLP shows hepatoprotective effects in a swine partial hepatectomy model. OLP may have the potential to ameliorate patients' outcomes after hepatectomy or liver transplantation.

Graft reconditioning with nitric oxide gas in rat liver transplantation from cardiac death donors

BACKGROUND

Liver transplant outcomes using grafts donated after cardiac death (DCD) remain poor.

METHODS

We investigated the effects of ex vivo reconditioning of DCD grafts with venous systemic oxygen persufflation using nitric oxide gas (VSOP-NO) in rat liver transplants. Orthotopic liver transplants were performed in Lewis rats, using DCD grafts prepared using static cold storage alone (group-control) or reconditioning using VSOP-NO during cold storage (group-VSOP-NO). Experiment I: In a 30-min warm ischemia model, graft damage and hepatic expression of inflammatory cytokines, endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), and endothelin-1 (ET-1) were examined, and histologic analysis was performed 2, 6, 24, and 72 hr after transplantation. Experiment II: In a 60-min warm ischemia model, grafts were evaluated 2 hr after transplantation (6 rats/group), and survival was assessed (7 rats/group).

RESULTS

Experiment I: Group-VSOP-NO had lower alanine aminotransferase (ALT) (P<0.001), hyaluronic acid (P<0.05), and malondialdehyde (MDA) (P<0.001), hepatic interleukin-6 expression (IL-6) (P<0.05), and hepatic tumor necrosis factor-alpha (TNF-α) expression (P<0.001). Hepatic eNOS expression (P<0.001) was upregulated, whereas hepatic iNOS (P<0.01) and ET-1 (P<0.001) expressions were downregulated. The damage of hepatocyte and sinusoidal endothelial cells (SECs) were lower in group-VSOP-NO.Experiment II: VSOP-NO decreased ET-1 and 8-hydroxy-2'deoxyguanosine (8-OHdG) expression and improved survival after transplantation by 71.4% (P<0.01).

CONCLUSION

These results suggest that VSOP-NO effectively reconditions warm ischemia-damaged grafts, presumably by decreasing ET-1 upregulation and oxidative damage.

Attenuation of steatohepatitis, fibrosis, and carcinogenesis in mice fed a methionine-choline deficient diet by CCAAT/enhancer-binding protein homologous protein deficiency

BACKGROUND AND AIMS

Hepatic steatosis is a metabolic liver disease with the potential to progress to steatohepatitis, cirrhosis, and hepatocellular carcinoma (HCC). The aim of this study was to investigate the impact of CCAAT/enhancer-binding protein homologous protein (CHOP) deficiency in the development of steatosis-associated progression of HCC.

METHODS

Eight-week-old wild-type (WT) and CHOP knockout (CHOP-/-) mice were fed a normal or methionine-choline-deficient (MCD) diet. Mice were sacrificed after 3 weeks, and steatosis, inflammation, apoptosis, and liver damage were assessed. We also evaluated fibrosis after 8 weeks of nutrition intervention. To explore the role of CHOP in liver carcinogenesis, 25 mg/kg of diethylnitrosamine (DEN) was injected intraperitoneally into 2-week-old mice, which were then fed the aforementioned diets from 8 to 24 weeks of age. CHOP expression in HCC patient livers was also evaluated.

RESULTS

CHOP deficiency did not affect steatosis but significantly reduced apoptotic cells, inflammation scores, and serum liver enzymes. It also significantly suppressed total serum bilirubin levels, fibrotic area size, and messenger RNA expression of profibrotic cytokines. DEN-initiated carcinogenesis was promoted by the MCD diet, while CHOP deficiency significantly attenuated the total number and maximum diameter of tumors and the Ki-67 labeling index. In human livers, CHOP expression was enhanced in parallel with non-alcoholic steatohepatitis-to-HCC progression.

CONCLUSIONS

CHOP deficiency attenuated apoptosis, inflammation, fibrosis, and tumorigenesis under fat-loading conditions, indicating that a therapeutic strategy targeting CHOP might be effective for fat-induced liver injury and protecting against promotion of carcinogenesis in patients with liver steatosis.

New paradigms in post-hepatectomy liver failure

INTRODUCTION

Liver failure after hepatectomy remains the most feared postoperative complication. Many risk factors are already known, related to patient's comorbidities, underlying liver disease, received treatments and type of resection. Preoperative assessment of functional liver reserve must be a priority for the surgeon.

METHODS

Physiopathology of post-hepatectomy liver failure is not comparable to fulminant liver failure. Liver regeneration is an early phenomenon whose cellular mechanisms are beginning to be elucidated and allowing most of the time to quickly recover a functional organ. In some cases, microscopic and macroscopic disorganization appears. The hepatocyte hyperproliferation and the asynchronism between hepatocytes and non-hepatocyte cells mitosis probably play a major role in this pathogenesis.

RESULTS

Many peri- or intra-operative techniques try to prevent the occurrence of this potentially lethal complication, but a better understanding of involved mechanisms might help to completely avoid it, or even to extend the possibilities of resection.

CONCLUSION

Future prevention and management may include pharmacological slowing of proliferation, drug or physical modulation of portal flow to reduce shear-stress, stem cells or immortalized hepatocytes injection, and liver bioreactors. Everything must be done to avoid the need for transplantation, which remains today the most efficient treatment of liver failure.

Effect of olprinone on liver microstructure in rat partial liver transplantation

BACKGROUND

Donor safety is a major concern in living-donor liver transplantation. However, partial grafts do not meet the functional demands of recipients and lead to small-for-size syndrome (SFSS). In a previous study, we showed that olprinone (OLP), a selective phosphodiesterase ІІІ inhibitor, up-regulates endothelial nitric oxide synthase level in the liver and attenuates shear stress, sinusoidal endothelial cell injury, and hepatocyte apoptosis after excessive liver resection in a rat model. We aimed to examine whether OLP treatment has beneficial effects on SFSS in a rat model of partial liver transplantation (PLT).

METHODS

We performed experiments in a rat model of 30% PLT. In the OLP group, we inserted an osmotic pump with OLP into the peritoneal cavity 48 h before liver graft sampling. Recipient rats were not treated with OLP. We examined the liver microstructure by electron microscopy and biochemical examination, and determined the 7-d survival of recipients.

RESULTS

In the OLP group 1 h after PLT, the sinusoidal endothelial cells of the liver were well preserved and we observed few vacuolar structures in hepatocytes. The total serum bilirubin level 1 wk after PLT tended to be lower in the OLP group than in the controls, and the liver microstructures were also well preserved in the OLP group. The probability of survival in the OLP group (100%; 14 of 14 rats) was significantly higher than that in the control group (75%; 15 of 20 rats).

CONCLUSIONS

Olprinone treatment was demonstrated to have therapeutic potential to overcome SFSS.

Sorafenib attenuates monocrotaline-induced sinusoidal obstruction syndrome in rats through suppression of JNK and MMP-9

BACKGROUND & AIMS

Sinusoidal obstruction syndrome (SOS) is a drug-induced liver injury that occurs with oxaliplatin treatment and is associated with postoperative morbidity after hepatectomy. The aim of this study was to investigate the effects of sorafenib in a monocrotaline (MCT)-induced model of SOS in rats.

METHODS

Rats were divided into groups treated with sorafenib (2mg/kg) or vehicle, 36 h and 12h before MCT (90 mg/kg) administration by gavage. Liver tissues and blood were sampled 48 h after MCT administration to evaluate SOS. Survival after hepatectomy was examined and immunohistochemistry and electron microscopy were performed to assess sinusoidal injury.

RESULTS

In the vehicle group, liver histology showed sinusoidal dilatation, coagulative necrosis of hepatocytes, endothelial damage of the central vein, and sinusoidal hemorrhage. In the sorafenib group, these changes were significantly suppressed, total SOS scores were significantly decreased, and the elevation of serum transaminase levels observed in the vehicle group was significantly reduced. Survival after hepatectomy was significantly higher in the sorafenib group compared to the vehicle group (45% vs. 20%, p=0.0137). Immunohistochemistry and electron microscopy revealed a protective effect of sorafenib on sinusoidal endothelial cells at 6h after MCT treatment. Sorafenib also attenuated the activity of metallopeptidase-9 (MMP-9) and phosphorylation of c-Jun N-terminal kinase (JNK).

CONCLUSIONS

Sorafenib reduced the severity of MCT-induced SOS in rats through suppression of MMP-9 and JNK activity, resulting in improvement of survival after hepatectomy.