Salvage effect of the vascular endothelial growth factor on chemically induced acute severe liver injury in rats

The vascular endothelial growth factor signaling pathway regulates liver sinusoidal endothelial cells during liver regeneration after partial hepatectomy

INTRODUCTION

Liver regeneration after partial hepatectomy is a very complex and well-regulated procedure. It utilizes all liver cell types, which are associated with signaling pathways involving growth factors, cytokines, and stimulatory and inhibitory feedback of several growth-related signals. Liver sinusoidal endothelial cells (LSECs) contribute to liver regeneration after partial hepatectomy. Vascular endothelial growth factor (VEGF) has various functions in LSECs. In this review, we summarize the relationship between VEGF and LSECs involving VEGF regulatory activity in the vascular endothelium.

AREAS COVERED

Maintenance of the fenestrated LSEC phenotype requires two VEGF pathways: VEGF stimulated-NO acting through the cGMP pathway and VEGF independent of nitric oxide (NO). The results suggest that VEGF is a key regenerating mediator of LSECs in the partial hepatectomy model. NO-independent pathway was also essential to the maintenance of the LSEC in liver regeneration.

EXPERT OPINION

Liver regeneration remains a fascinating and significative research field in recent years. The liver involved of molecular pathways except for LSEC-VEGF pathways that make the field of liver further depth studies should be put into effect to elaborate the undetermined confusions, which will be better to understand liver regeneration.

Bevacizumab exacerbates sinusoidal obstruction syndrome (SOS) in the animal model and increases MMP 9 production

Background

Thanks to modern multimodal treatment the ouctome of patients with colorectal cancer has experienced significant improvements. As a downside, agent specific side effects have been observed such as sinusoidal obstruction syndrome (SOS) after oxaliplatin chemotherapy (OX). Bevazicumab targeting VEGF is nowadays comprehensively used in combination protocols with OX but its impact on hepatotoxicity is thus far elusive and focus of the present study.

Results

After MCT administration 67% of animals developed SOS. GOT serum concentration significantly increased in animals developing SOS (p < 0.001). Subsequent to MCT administration 100% of animals treated with Anti-VEGF developed SOS. In contrast, animals receiving VEGF developed SOS merely in 40% while increasing the VEGF dose led to a further decrease in SOS development to 25%. MMP 9 concentration in animals developing SOS was significantly higher compared to controls (p < 0,001). Additional treatment with Anti-VEGF increased the MMP 9 concentration significantly (p < 0,05).

Conclusions

Preservation of liver function is a central goal in both curative and palliative treatment phases of patients with CRC. Thus, knowledge about hepatotoxic side effects of chemotherapeutic and biological agents is crucial. From the results it can be concluded that Anti-VEGF exacerbates SOS paralleled by MMP 9 production. Therefore, OX-Bevacizumab combination therapies should be administered with caution, especially if liver parenchyma damage is apparent.

Methods

Male Sprague-Dawley rats were gavaged Monocrotaline (MCT) to induce SOS. Recombinant VEGF or an Anti-VEGF antibody was administered to MCT-treated rats and the hepatotoxic effect monitored in defined time intervals. MMP 9 expression in the liver was measured by ELISA.

Heat stress prevents lipopolysaccharide-induced apoptosis in pulmonary microvascular endothelial cells by blocking calpain/p38 MAPK signalling

Pulmonary microvascular endothelial cells (PMECs) injury including apoptosis plays an important role in the pathogenesis of acute lung injury during sepsis. Our recent study has demonstrated that calpain activation contributes to apoptosis in PMECs under septic conditions. This study investigated how calpain activation mediated apoptosis and whether heat stress regulated calpain activation in lipopolysaccharides (LPS)-stimulated PMECs. In cultured mouse primary PMECs, incubation with LPS (1 μg/ml, 24 h) increased active caspase-3 fragments and DNA fragmentation, indicative of apoptosis. These effects of LPS were abrogated by pre-treatment with heat stress (43 °C for 2 h). LPS also induced calpain activation and increased phosphorylation of p38 MAPK. Inhibition of calpain and p38 MAPK prevented apoptosis induced by LPS. Furthermore, inhibition of calpain blocked p38 MAPK phosphorylation in LPS-stimulated PMECs. Notably, heat stress decreased the protein levels of calpain-1/2 and calpain activities, and blocked p38 MAPK phosphorylation in response to LPS. Additionally, forced up-regulation of calpain-1 or calpain-2 sufficiently induced p38 MAPK phosphorylation and apoptosis in PMECs, both of which were inhibited by heat stress. In conclusion, heat stress prevents LPS-induced apoptosis in PMECs. This effect of heat stress is associated with down-regulation of calpain expression and activation, and subsequent blockage of p38 MAPK activation in response to LPS. Thus, blocking calpain/p38 MAPK pathway may be a novel mechanism underlying heat stress-mediated inhibition of apoptosis in LPS-stimulated endothelial cells.

A Potential Mechanism for the Anti-Apoptotic Property of Koumine Involving Mitochondrial Pathway in LPS-Mediated RAW 264.7 Macrophages

Koumine is a kind of alkaloid extracted from Gelsemium elegans (G. elegans). Benth, which has shown promise as an anti-tumor, anxiolytic, and analgesic agent. In our present study, the effect of koumine on lipopolysaccharide (LPS)-mediated RAW 264.7 cell apoptosis was evaluated. MTT assays showed that koumine obviously increased cell viability in LPS-mediated RAW 264.7 macrophages. Preincubation with koumine ameliorated LPS-medicated apoptosis by decreasing reactive oxygen species (ROS) production, which resulted in a significant decrease in the levels of nitric oxide (NO) and inducible nitric oxide synthase (iNOS). In addition, koumine-pretreated RAW 264.7 macrophages exhibited reduction of LPS-induced levels of TNF-α, IL-1β, and IL-6 mRNA. Furthermore, pretreatment with koumine suppressed LPS-mediated p53 activation, loss of mitochondrial membrane potential, caspase-3 activation, decrease of Bcl-2 expression, and elevation of Bax and caspase-3 expressions, suggesting that koumine might act directly on RAW 264.7 cells to inhibit LPS-induced apoptosis. It seems as though the mechanism that koumine possesses is the anti-apoptotic effect mediated by suppressing production of ROS, activation of p53, and mitochondrial apoptotic pathways in RAW 264 cells. Koumine could potentially serve as a protective effect against LPS-induced apoptosis.

Cellularized biosynthetic microhydrogel polymers for intravascular liver tissue regeneration therapy

INTRODUCTION

The liver is the natural microenvironment for hepatocytes transplantation but unfortunately engraftment efficiency is low. Cell-laden microhydrogels made of fibrinogen attached to poly(ethylene glycol) (PEG)-diacrylate side chains, were used as a cell carrier, for intravascular transplantation. This approach may reduce shear stress and immediate immunological pressure after intravascular transplantation and provide biomatrix for environmental support.

AIMS

In vitro assessment of HuH-7 viability and function after polymerization within PEGylated fibrinogen-hydrogel. In vivo assessment of intraportal transplantation of cell-laden microhydrogels with rat adult parenchymal cells.

METHODS

(1) In vitro assessment of HuH-7 cell viability and function, after cell-laden hydrogel (hydrogel volume 30 μL) fabrication, by propidium iodide (PI)/fluorescein diacetate (FDA), and MTT assays, albumin concentration and CYP1A activity. (2) Fabrication of cell-laden microhydrogels and their intraportal transplantion. Engraftment efficiency in vivo was evaluated by real-time qPCR of Y chromosome (SRY gene) and histology.

RESULTS

The viability of cells in hydrogels in culture was comparable to viability of not embedded cells during the first 48 h. However, the viability of cells in hydrogels was reduced after 72 h compared with not embedded cells. Activity of CYP1A in hydrogel was comparable to that of not embedded cells (4.33±1 pmole/μg DNA/4 h vs. 5.13±1 pmole/μg DNA/4 h, respectively). Albumin concentration increased at day 3 in hydrogels to 1.4±0.6 μg/10(4)/24 h and was greater to that of free cells, 0.3±0.1 μg/10(4)/24 h. Cell-laden microhydrogels at a size of 150-150-600 μm (6×10(6) cells/rat) showed better engraftment efficiency at 21 days post-transplantation, compared with isolated cell transplantation (54.6%±5% vs. 1.8%±1.2%, p<0.001).

CONCLUSIONS

The in vitro HuH-7 viability and function after polymerization in PEGylated fibrinogen hydrogel was comparable to cells without the hydrogel. Long-term survival and engraftment efficiency of intravascular transplanted adult hepatocytes is much better in within cell-laden microhydrogels compared with isolated cells. The overall efficiency of the procedure needs to be improved.

Hypoxia preconditioned bone marrow mesenchymal stem cells promote liver regeneration in a rat massive hepatectomy model

Introduction

Bone marrow mesenchymal stem cells (BMMSCs) have been reported to facilitate liver regeneration after toxic injuries. However, the effect of BMMSCs on liver regeneration after massive hepatectomy is barely studied. Here we explored whether infusion of BMMSCs promotes liver regeneration in a rat massive hepatectomy model.

Methods

Hypoxia preconditioning was achieved by culturing BMMSCs under a hypoxia environment. Then 85% hepatectomy was performed and hypoxia or normoxia preconditioned BMMSCs were infused into the portal vein. A group of rats received vascular endothelial growth factor (VEGF) neutralizing antibody perioperatively, and underwent 85% hepatectomy and a subsequent infusion of hypoxia preconditioned BMMSCs to verify the role of VEGF in the effects of BMMSCs on liver regeneration. Liver samples were collected and liver regeneration was evaluated postoperatively.

Results

Hypoxia preconditioning enhanced the expression of VEGF in BMMSCs in vitro. Infusion of BMMSCs promoted proliferation of hepatocytes, reflected by elevated cyclin D₁ expression and proliferating cell nuclear antigen-positive hepatocytes. However, BMMSC infusion did not improve the serum albumin level, liver weight/body weight ratio, and survival after operation. Infusion of hypoxia preconditioned BMMSCs significantly elevated cyclin D₁, proliferating cell nuclear antigen-positive hepatocytes, liver weight/body weight ratio, and survival compared with normoxia preconditioned BMMSCs, accompanied by an increased serum albumin level. The level of VEGF in liver homogenate was much higher in hypoxia preconditioned BMMSC-treated animals than in other groups. In addition, the perioperative injection of VEGF neutralizing antibody significantly blocked the therapeutic effects of hypoxia preconditioned BMMSCs on liver injury and regeneration in this model.

Conclusion

Hypoxia preconditioned BMMSCs enhanced liver regeneration after massive hepatectomy in rats, possibly by upregulating the level of VEGF.

Liver sinusoidal endothelial cells and liver regeneration

Liver sinusoidal endothelial cells (LSECs) have long been noted to contribute to liver regeneration after liver injury. In normal liver, the major cellular source of HGF is the hepatic stellate cell, but after liver injury, HGF expression has been thought to increase markedly in proliferating LSECs. However, emerging data suggest that even after injury, LSEC expression of HGF does not increase greatly. In contrast, bone marrow progenitor cells of LSECs (BM SPCs), which are rich in HGF, are recruited to the liver after injury. This Review examines liver regeneration from the perspective that BM SPCs that have been recruited to the liver, rather than mature LSECs, drive liver regeneration.

Preoperative administration of bevacizumab is safe for patients with colorectal liver metastases

AIM: To assess the impact of preoperative neoadjuvant bevacizumab (Bev) on the outcome of patients undergoing resection for colorectal liver metastases (CLM).

METHODS: Eligible trials were identified from Medline, Embase, Ovid, and the Cochrane database. The data were analyzed with fixed-effects or random-effects models using Review Manager version 5.0.

RESULTS: Thirteen nonrandomized studies with a total of 1431 participants were suitable for meta-analysis. There was no difference in overall morbidity and severe complications between the Bev + group and Bev - group (43.3% vs 36.8%, P = 0.06; 17.1% vs 11.4%, P = 0.07, respectively). Bev-related complications including wound and thromboembolic/bleeding events were also similar in the Bev + and Bev - groups (14.4% vs 8.1%, P = 0.21; 4.1% vs 3.8%, P = 0.98, respectively). The incidence and severity of sinusoidal dilation were lower in patients treated with Bev than in patients treated without Bev (43.3% vs 63.7%, P < 0.001; 16.8% vs 46.5%, P < 0.00, respectively).

CONCLUSION: Bev can be safely administered before hepatic resection in patients with CLM, and has a protective effect against hepatic injury in patients treated with oxaliplatin chemotherapy.

Hepatic vascular endothelial growth factor regulates recruitment of rat liver sinusoidal endothelial cell progenitor cells

BACKGROUND & AIMS

After liver injury, bone marrow-derived liver sinusoidal endothelial cell progenitor cells (BM SPCs) repopulate the sinusoid as liver sinusoidal endothelial cells (LSECs). After partial hepatectomy, BM SPCs provide hepatocyte growth factor, promote hepatocyte proliferation, and are necessary for normal liver regeneration. We examined how hepatic vascular endothelial growth factor (VEGF) regulates recruitment of BM SPCs and their effects on liver injury.

METHODS

Rats were given injections of dimethylnitrosamine to induce liver injury, which was assessed by histology and transaminase assays. Recruitment of SPCs was analyzed by examining BM SPC proliferation, mobilization to the circulation, engraftment in liver, and development of fenestration (differentiation).

RESULTS

Dimethylnitrosamine caused extensive denudation of LSECs at 24 hours, followed by centrilobular hemorrhagic necrosis at 48 hours. Proliferation of BM SPCs, the number of SPCs in the bone marrow, and mobilization of BM SPCs to the circulation increased 2- to 4-fold by 24 hours after injection of dimethylnitrosamine; within 5 days, 40% of all LSECs came from engrafted BM SPCs. Allogeneic resident SPCs, infused 24 hours after injection of dimethylnitrosamine, repopulated the sinusoid as LSECs and reduced liver injury. Expression of hepatic VEGF messenger RNA and protein increased 5-fold by 24 hours after dimethylnitrosamine injection. Knockdown of hepatic VEGF with antisense oligonucleotides completely prevented dimethylnitrosamine-induced proliferation of BM SPCs and their mobilization to the circulation, reduced their engraftment by 46%, completely prevented formation of fenestration after engraftment as LSECs, and exacerbated dimethylnitrosamine injury.

CONCLUSIONS

BM SPC recruitment is a repair response to dimethylnitrosamine liver injury in rats. Hepatic VEGF regulates recruitment of BM SPCs to liver and reduces this form of liver injury.

Implanted adipose-derived stem cells attenuate small-for-size liver graft injury by secretion of VEGF in rats

Graft injury after small-for-size liver transplantation impairs graft function and threatens the survival of the recipients. The use of adipose-derived stem cells (ADSCs) for liver injury protection and repair is promising. Our aim was to investigate the role of vascular endothelial growth factor (VEGF) secreted by ADSCs in the treatment of small-for-size liver graft injury. Studies were performed using ADSCs with VEGF secretion blocked by RNA interference. In vitro, ADSCs prevented apoptosis of freshly isolated liver sinusoidal endothelial cells (LSECs) by secretion of VEGF. Syngeneic 35% orthotopic liver transplantation followed by implantation of syngeneic ADSCs through the portal vein system was performed using Wistar rats. We found VEGF secreted by implanted ADSCs improved graft microcirculatory disturbances, serum liver function parameters and survival. The improved microcirculatory status was also reflected by reduced hepatocellular damage, especially LSEC apoptosis and improved liver regeneration. These effects were accompanied by decreased expression of endothelin receptor type A, increased Bcl-2/Bax ratio, decreased expression of Bad and elevated proportion of phosphorylated Bad. In conclusion, implanted syngeneic ADSCs attenuated small-for-size liver graft injuries and subsequently enhanced liver regeneration in a rat 35% liver transplantation model. The VEGF secreted by implanted ADSCs played a crucial role in this process.

A Macaca mulatta model of fulminant hepatic failure

AIM: To establish an appropriate primate model of fulminant hepatic failure (FHF).

METHODS: We have, for the first time, established a large animal model of FHF in Macaca mulatta by intraperitoneal infusion of amatoxin and endotoxin. Clinical features, biochemical indexes, histopathology and iconography were examined to dynamically investigate the progress and outcome of the animal model.

RESULTS: Our results showed that the enzymes and serum bilirubin were markedly increased and the enzyme-bilirubin segregation emerged 36 h after toxin administration. Coagulation activity was significantly decreased. Gradually deteriorated parenchymal abnormality was detected by magnetic resonance imaging (MRI) and ultrasonography at 48 h. The liver biopsy showed marked hepatocyte steatosis and massive parenchymal necrosis at 36 h and 49 h, respectively. The autopsy showed typical yellow atrophy of the liver. Hepatic encephalopathy of the models was also confirmed by hepatic coma, MRI and pathological changes of cerebral edema. The lethal effects of the extrahepatic organ dysfunction were ruled out by their biochemical indices, imaging and histopathology.

CONCLUSION: We have established an appropriate large primate model of FHF, which is closely similar to clinic cases, and can be used for investigation of the mechanism of FHF and for evaluation of potential medical therapies.

A simulation shows that early treatment of chronic hepatitis B infection can cut deaths and be cost-effective

Chronic hepatitis B affects between 800,000 and two million people in the United States and causes 4,000 deaths each year. Yet the costs and benefits of treatment have not been fully evaluated. Using a model that simulates disease progression, we compare treatment programs for hepatitis B that start at an early stage of the disease to treatment that begins at a late stage. Our analysis concludes that early hepatitis B care can improve health, reduce premature deaths, and prevent expensive complications, making it highly cost-effective in the long term. Our results demonstrate the importance of screening for hepatitis B among at-risk groups and then linking screening to treatment. They also illustrate how predictive models can be used to evaluate strategies for improving access to care.

Human anti-microbial cathelicidin peptide LL-37 suppresses the LPS-induced apoptosis of endothelial cells

Sepsis is a systemic disease resulting from harmful host response to bacterial infections. During the exacerbation of severe sepsis or septic shock, apoptosis of endothelial cells is induced in susceptible organs such as the lung and liver and triggers microcirculatory disorder and organ dysfunction. LPS, an outer membrane component of Gram-negative bacteria, is one of the major virulence factors for the pathogenesis. We previously reported that LL-37, a human anti-microbial cathelicidin peptide, potently neutralizes the biological activity of LPS and protects mice from lethal endotoxin shock. However, the effect of LL-37 on the LPS-induced endothelial cell apoptosis remains to be clarified. In this study, to further elucidate the action of LL-37 on severe sepsis/endotoxin shock, we investigated the effects of LL-37 on the LPS-induced endothelial cell apoptosis in vitro and in vivo using lung-derived normal human microvascular blood vessel endothelial cells (HMVEC-LBls) and D-galactosamine hydrochloride (D-GalN)-sensitized murine endotoxin shock model. LL-37 suppressed the LPS-induced apoptosis of HMVEC-LBls. In addition, LL-37 inhibited the binding of LPS possibly to the LPS receptors (CD14 and toll-like receptor 4) expressed on the cells. Thus, LL-37 can suppress the LPS-induced apoptosis of HMVEC-LBls via the inhibition of LPS binding to the cells. Furthermore, LL-37 drastically suppressed the apoptosis of hepatic endothelial cells as well as hepatocytes in the liver of murine endotoxin shock model. Together, these observations suggest that LL-37 could suppress the LPS-induced apoptosis of endothelial cells, thereby attenuating lethal sepsis/endotoxin shock.

Protective effects of ACLF sera on metabolic functions and proliferation of hepatocytes co-cultured with bone marrow MSCs in vitro

AIM: To investigate whether the function of hepatocytes co-cultured with bone marrow mesenchymal stem cells (MSCs) could be maintained in serum from acute-on-chronic liver failure (ACLF) patients.

METHODS: Hepatocyte supportive functions and cytotoxicity of sera from 18 patients with viral hepatitis B-induced ACLF and 18 healthy volunteers were evaluated for porcine hepatocytes co-cultured with MSCs and hepatocyte mono-layered culture, respectively. Chemokine profile was also examined for the normal serum and liver failure serum.

RESULTS: Hepatocyte growth factor (HGF) and Tumor necrosis factor; tumor necrosis factor (TNF)-α were remarkably elevated in response to ACLF while epidermal growth factor (EGF) and VEGF levels were significantly decreased. Liver failure serum samples induced a higher detachment rate, lower viability and decreased liver support functions in the homo-hepatocyte culture. Hepatocytes co-cultured with MSCs could tolerate the cytotoxicity of the serum from ACLF patients and had similar liver support functions compared with the hepatocytes cultured with healthy human serum in vitro. In addition, co-cultured hepatocytes maintained a proliferative capability despite of the insult from liver failure serum.

CONCLUSION: ACLF serum does not impair the cell morphology, viability, proliferation and overall metabolic capacities of hepatocyte co-cultured with MSCs in vitro.

Transplantation of porcine hepatocytes cultured with polylactic Acid-o-carboxymethylated chitosan nanoparticles promotes liver regeneration in acute liver failure rats

In this study, free porcine hepatocytes suspension (Group A), porcine hepatocytes embedded in collagen gel (Group B), porcine hepatocytes cultured with PLA-O-CMC nanoparticles and embedded in collagen gel (Group C), and PLA-O-CMC nanoparticles alone (Group D) were transplanted into peritoneal cavity of ALF rats, respectively. The result showed that plasma HGF levels were elevated post-transplantation with a peak at 12 hr. The rats in Group C showed highest plasma HGF levels at 2, 6, 12, 24 and 36 hr post-transplantation and lowest HGF level at 48 hr. Plasma VEGF levels were elevated at 48 hr post-transplantation with a peak at 72 hr. The rats in Group C showed highest plasma HGF levels at 48, 72, and 96 hr post-transplantation. The liver functions in Group C were recovered most rapidly. Compared with Group B, Group C had significant high liver Kiel 67 antigen labeling index (Ki-67 LI) at day 1 post-HTx (P < .05). Ki-67 LI in groups B and C was higher than that in groups A and D at days 5 and 7 post-HTx. In conclusion, intraperitoneal transplantation of porcine hepatocytes cultured with PLA-O-CMC nanoparticles and embedded in collagen gel can promote significantly liver regeneration in ALF rats.

Serum levels of platelet-derived growth factor-BB and vascular endothelial growth factor as prognostic factors for patients with fulminant hepatic failure

BACKGROUND AND AIMS

In animal models for acute liver injury, the administration of some angiogenic factors such as vascular endothelial growth factor (VEGF) and granulocyte-colony stimulating factor (G-CSF) are shown to reduce liver injury and improve liver proliferative capacity. The aim of the present study was to assess the role of angiogenic factors in fulminant hepatic failure (FHF).

METHODS

Serum levels of nine angiogenic factors (angiopoietin-2, follistatin, G-CSF, hepatocyte growth factor [HGF], interleukin-8, leptin, platelet-derived growth factor [PDGF]-BB, platelet endothelial cell adhesion molecule-1 and VEGF) were measured using the Bio-Plex Protein Array System in 30 patients, 17 of whom were diagnosed with FHF, 13 with acute hepatitis (AH), and 20 controls.

RESULTS

Serum levels of PDGF-BB and VEGF were lower in FHF patients than AH patients and controls (PDGF-BB; 2050±1572 pg/mL vs 4521±2419 pg/mL vs 8506±5500 pg/mL, VEGF; 39±38 pg/mL vs 144±122 pg/mL vs 205±121 pg/mL). By using univariate logistic regression models, serum levels of PDGF-BB and VEGF were associated with poor outcomes. Serum PDGF-BB levels were strongly correlated with serum VEGF levels (r=0.70). Furthermore, serum PDGF-BB levels were significantly correlated with platelet counts (r=0.79), PT activity (r=0.37) and D.Bil/T.Bil ratio (r=0.50), while serum VEGF levels were significantly correlated with platelet counts (r=0.68) and PT activity (r=0.38).

CONCLUSIONS

We consider that serum levels of PDGF-BB and VEGF are worth investigating as biomarkers for predicting outcomes of FHF patients.

The vascular endothelial growth factor (VEGF) receptor-2 is a major regulator of VEGF-mediated salvage effect in murine acute hepatic failure

Although administration of the vascular endothelial growth factor (VEGF), a potent angiogenic factor, could improve the overall survival of destroyed sinusoidal endothelial cells (SEC) in chemically induced murine acute hepatic failure (AHF), the mechanistic roles of the VEGF receptors have not been elucidated yet. The respective roles of VEGF receptors; namely, Flt-1 (VEGFR-1: R1) and KDR/Flk-1 (VEGFR-2: R2), in the D-galactosamine (Gal-N) and lipopolysaccharide (LPS)-induced AHF were elucidated with specific neutralizing monoclonal antibody against R1 and R2 (R1-mAb and R2-mAb, respectively). The serum ALT elevation, with a peak at 24 h after Gal-N+LPS intoxication, was markedly augmented by means of the R1-mAb and R2-mAb. The aggregative effect of R2-mAb was more potent than that of R1-mAb, and the survival rate was 70% in the R2-mAb-treated group and 100% in the other groups. The results of SEC destruction were almost parallel to those of the ALT changes. Our in-vitro study showed that R1-mAb and R2-mAb significantly worsened the Gal-N+LPS-induced cytotoxicity and apoptosis of SEC mediated by caspase-3, which were almost of similar magnitude to those in the in-vivo study. In conclusion, these results indicated that R2 is a major regulator of the salvage effect of VEGF on the maintenance of SEC architecture and the anti-apoptotic effects against chemically-induced murine AHF.

No contribution of umbilical cord mesenchymal stromal cells to capillarization and venularization of hepatic sinusoids accompanied by hepatic differentiation in carbon tetrachloride-induced mouse liver fibrosis

BACKGROUND AIMS

The acceleration of capillarization and venularization of hepatic sinusoids after cell therapy would not be beneficial to restoration after liver disease. The goal was to observe the effects of umbilical cord (UC)-derived mesenchymal stromal cells (MSC) on liver microcirculation and their therapeutic potential in liver fibrosis.

METHODS

Human UC MSC labeled with or without CM-DIL were transplanted into NOD/SCID mice with carbon tetrachloride (CCl4)-induced chronic liver fibrosis models. Because of the high autofluorescence on the injured liver sections, we used immunohistochemistry, Western blot and reverse transcriptase-polymerase chain reaction (RT-PCR), but not immunofluorescence, in order to avoid false images under a confocal fluorescence microscope.

RESULTS

Human-specific alpha-fetoprotein and albumin mRNA and proteins were detected in CCl4-treated mouse livers receiving human UC MSC transplants. We only observed the gene expression of human-specific endothelial-like cells markers CD31 and KDR by RT-PCR, but not protein expression by immunohistochemistry, in UC MSC-transplanted mouse livers. Vascular endothelial growth factor (VEGF) expression in injured livers 4 weeks after UC MSC transplantation was higher than in normal livers. However, UC MSC injection did not increase significantly the vascular density labeled by CD31 and (vWF) in the injured livers of UC MSC-transplanted mice compared with non-transplanted mice after CCl4 treatment. In addition, liver function was partly improved after UC MSC transplantation.

CONCLUSIONS

Human UC MSC can differentiate into hepatocyte-like cells but do not accelerate the capillarization and venularization of hepatic sinusoids, finally leading to the partial improvement of liver function in mice with CCl4-mediated chronic liver fibrosis.

Qizhu Granules downregulate the expression of vascular endothelial growth factor in carbon tetrachloride-induced liver fibrosis in rats

AIM: To observe the effects of Qizhu Granules on the expression of vascular endothelial growth factor (VEGF) in carbon tetrachloride (CCl₄)-induced liver fibrosis in rats.

METHODS: Rats were randomized into normal control group, model control group, Qizhu Granule treatment group and Compound Biejia Ruangan Tablet treatment group. After liver fibrosis was induced in rats by intraperitoneal injection of CCl₄, Qizhu Granules and Compound Biejia Ruangan Tablets were given. Liver tissue samples were taken on days 1, 2 and 3 and at weeks 1, 2, 4, 8 and 12 for real-time fluorescence quantitative PCR detection of the expression of VEGF mRNA.

RESULTS: The expression levels of VEGF mRNA in Qizhu Granule treatment group on days 1, 2 and 3 and at weeks 1, 2 and 12 were significantly lower than those in the model control group (0.37 ± 0.33 vs 0.48 ± 0.26, 0.24 ± 0.20 vs 0.50 ± 0.65, 0.36 ± 0.24 vs 0.45 ± 0.29, 0.25 ± 0.14 vs 0.48 ± 0.41, 0.18 ± 0.60 vs 0.30 ± 0.30 and 0.40 ± 0.01 vs 0.51 ± 0.74; all P < 0.05 or 0.01).

CONCLUSION: Qizhu Granules can prevent the progression of liver angiogenesis and alleviate liver fibrosis possibly by downregulating the expression of VEGF mRNA in rats.

An overview of animal models for investigating the pathogenesis and therapeutic strategies in acute hepatic failure

Acute hepatic failure (AHF) is a severe liver injury accompanied by hepatic encephalopathy which causes multiorgan failure with an extremely high mortality rate, even if intensive care is provided. Management of severe AHF continues to be one of the most challenging problems in clinical medicine. Liver transplantation has been shown to be the most effective therapy, but the procedure is limited by shortage of donor organs. Although a number of clinical trials testing different liver assist devices are under way, these systems alone have no significant effect on patient survival and are only regarded as a useful approach to bridge patients with AHF to liver transplantation. As a result, reproducible experimental animal models resembling the clinical conditions are still needed. The three main approaches used to create an animal model for AHF are: surgical procedures, toxic liver injury and infective procedures. Most common models are based on surgical techniques (total/partial hepatectomy, complete/transient devascularization) or the use of hepatotoxic drugs (acetaminophen, galactosamine, thioacetamide, and others), and very few satisfactory viral models are available. We have recently developed a viral model of AHF by means of the inoculation of rabbits with the virus of rabbit hemorrhagic disease. This model displays biochemical and histological characteristics, and clinical features that resemble those in human AHF. In the present article an overview is given of the most widely used animal models of AHF, and their main advantages and disadvantages are reviewed.

Bevacizumab protects against sinusoidal obstruction syndrome and does not increase response rate in neoadjuvant XELOX/FOLFOX therapy of colorectal cancer liver metastases

AIM

In patients suffering from colorectal cancer liver metastases, 5-fluorouracil-based chemotherapy plus oxaliplatin ensures superior response rates at the cost of hepatic injury. Knowledge about the consequences of bevacizumab on chemotherapy-induced hepatic injury and tumor response is limited.

METHODS

Resected liver specimens from patients of two prospective, non-randomized trials (5-fluorouracil/oxaliplatin+/-bevacizumab) were analyzed retrospectively. Hepatotoxicity to the non-tumor bearing liver was evaluated for sinusoidal obstruction syndrome, hepatic steatosis and fibrosis. Tumor response under chemotherapy was assessed according to Response Evaluation Criteria in Solid Tumors (RECIST).

RESULTS

Bevacizumab decreased the severity of the sinusoidal obstruction syndrome. Bevacizumab had no impact on hepatic steatosis and fibrosis. The addition of bevacizumab to chemotherapy had no effect on tumor response compared to combination chemotherapy alone.

CONCLUSIONS

This analysis shows that bevacizumab protects against the sinusoidal obstruction syndrome and thus provides the histological explanation of the safe use of bevacizumab prior to liver resection. Furthermore, we show that bevacizumab does not improve tumor response according to RECIST.

Differential vascular endothelial growth factor A protein expression between small hepatocellular carcinoma and cirrhosis correlates with serum vascular endothelial growth factor A and alpha-fetoprotein

BACKGROUND/AIMS

Drugs with antivascular endothelial growth factor A (anti-VEGF-A) action are under clinical evaluation with encouraging results in advanced hepatocellular carcinoma (HCC). The relative VEGF-A protein expression in non-advanced HCC and in the cirrhotic non-tumoral tissue in the same patient, a variable that could be important for treatment efficacy, has been investigated with conflicting results, only using the cirrhotic tissue surrounding the neoplasm (CS).

METHODS

We measured, for the first time, VEGF-A expression in non-advanced HCC and in the respective CS and cirrhotic tissue at a distance from the tumour (CD), in 24 patients who underwent liver transplantation.

RESULTS

VEGF-A protein was more expressed (P<0.05) in HCC than in CD, while no difference was found between HCC and CS. In HCC patients with a serum alpha-fetoprotein (AFP) higher than 20 ng/ml, VEGF-A protein expression in HCC was higher than in the corresponding CD in 83% of cases and AFP and serum VEGF-A corrected for the platelet count positively correlated with the differential VEGF-A protein expression between HCC and CD.

CONCLUSION

Our data provide a rationale for clinical trials involving anti-VEGF-A treatments in patients with non-advanced HCC, and suggest that serum AFP and VEGF-A are variables to be taken into account in these studies.

Identification and preliminary validation of novel biomarkers of acute hepatic ischaemia/reperfusion injury using dual-platform proteomic/degradomic approaches

Hepatic ischaemia/reperfusion (I/R), a major cause of liver damage associated with multiple trauma, haemorrhagic and septic shock, and liver transplantation, contributes significantly to multiple organ failure. Development of novel sensitive biomarkers that detect early stages of liver damage is vital for effective management and treatment of ischaemic liver injury. By using high-throughput immunoblotting and cation-anion exchange chromatography/reversed-phase liquid chromatography-tandem mass-spectrometry, we identified several hepatic proteins, including argininosuccinate synthase (ASS) and estrogen sulfotransferase (EST-1), which were degraded in the liver and rapidly released into circulation during I/R injury. ASS accumulated in serum within 10 min, reached a steady state at 30 min, and persisted up until 3 h after reperfusion following 30 min of total hepatic ischaemia. EST-1 appeared rapidly in blood and attained maximum within 1 hour followed by a decline at 3 h of reperfusion. No ASS or EST-1 protein was detected in serum of control or sham operated rats. ASS and EST-1 exhibited greater sensitivity and specificity toward I/R liver injury as compared with alanine aminotransferase (ALT), an established marker of hepatocellular necrosis. In contrast, serum ASS and EST-1 were undetectable in rats with chronic alcoholic liver disease, while the levels of ALT protein were significantly increased. In addition, ASS, but not EST-1 or ALT accumulated in blood only 6 h after treatment with hepatotoxic combination of lipopolysaccharide and D-galactosamine. These data demonstrate the utility of ASS and EST-1 as novel sensitive and specific biomarkers of acute liver ischaemic injury for prospective clinical studies.

Significance of morphological alteration by portal vein branch ligation in endotoxin-induced liver injury after partial hepatectomy

BACKGROUND

Regenerating liver after partial hepatectomy (PH) is susceptible to endotoxin. This study was conducted to investigate how morphological alteration by preoperative portal vein branch ligation (PVL) affects endotoxin-induced liver injury after PH.

METHODS

Male Sprague-Dawley rats were divided into a PVL group undergoing left PVL and into a non-PVL group receiving a sham operation. Seven days later, animals in both groups were subjected to PH (the left lateral, median and caudate lobes). Lipopolysaccharide (LPS) was intravenously administered to both groups 2 days after PH.

RESULTS

A significant increase in hepatocyte and sinusoidal endothelial cell proliferation assessed by Ki-67 immunostaining reached a peak at day 2 and 3 after PVL, respectively, in accordance with the changes in plasma interleukin-6 concentrations after PVL. The proliferation response of these cells after PH was observed in both groups, showing a significantly weaker response in the PVL group. The sinusoidal width after PH was significantly reduced in the non-PVL group when compared with that in the PVL group. LPS administration induced a marked elevation of plasma tumour necrosis factor-alpha levels in the non-PVL group compared with the PVL group. PVL before PH significantly attenuated endotoxin-induced functional and structural liver damage with greater hepatic polymorphonuclear leucocyte infiltration and microcirculatory derangement, resulting in an improvement in the 7-day survival rate.

CONCLUSIONS

Morphological alteration by PVL is of great advantage in preventing the development of endotoxin-induced liver injury in the regeneration process after PH.

Addition of bevacizumab to irinotecan- and oxaliplatin-based preoperative chemotherapy regimens does not increase morbidity after resection of colorectal liver metastases

BACKGROUND

Although commonly used in combination with irinotecan or oxaliplatin (iri/oxal) for treatment of colorectal liver metastases before extirpation, the effects of preoperative bevacizumab on surgical outcomes are not established. The objective of this retrospective study was to determine if addition of bevacizumab to iri/oxal preoperative chemotherapy increases morbidity after hepatic resection.

STUDY DESIGN

We compared demographics, clinicopathologic data, treatments, and postoperative outcomes between patients given preoperative iri/oxal with and without bevacizumab and patients who underwent hepatic resection within and after 8 weeks from the last dose of bevacizumab.

RESULTS

From 1996 to 2006, 96 patients were treated with preoperative iri/oxal; 39 (40.6%) received concurrent bevacizumab. Preoperative bevacizumab treatment was associated with less blood loss (median 425 mL versus 600 mL, p=0.01) and lower RBC transfusion rates (43.9% versus 23.1%, p=0.06) after partial hepatectomy on univariable analysis. Only age>or=70 years (hazard ratio=8.52, 95% CI [2.00 to 36.45]) and concurrent extrahepatic procedures (hazard ratio=4.12, 95% CI [1.49 to 11.39]) independently predicted RBC transfusion and overall complications, respectively. There were no differences in overall (43.6% versus 38.6%), severe (28.2% versus 24.6%), hepatic (17.9% versus 26.3%), wound (10.3% versus 7%), or thromboembolic or bleeding (2.6% versus 5.3%) complications (all p > 0.05). For patients treated with iri/oxal and bevacizumab, overall complications were more common when resection was performed within 8 weeks after the last bevacizumab dose (62.5% versus 30.4%), but this difference was not statistically significant (p=0.06).

CONCLUSIONS

If discontinued at least 8 weeks before hepatic resection, addition of bevacizumab to preoperative iri/oxal does not increase morbidity after hepatic resection.

VEGF isoforms and receptors expression throughout acute acetaminophen-induced liver injury and regeneration

Acetaminophen (APAP) is a widely-used analgesic and a known hepatotoxic agent. Vascular endothelial growth factor (VEGF) is a growth factor with multiple functional roles. VEGF plays an important role in angiogenesis and hepatic regeneration. The aim of this study was to determine the expression of VEGF isoforms and its receptors throughout liver regeneration after the administration of a toxic dose of APAP in rats. Ten groups of adult male rats received a dose of 3.5 g/kg b.w. of APAP per os. The rats were killed post administration at 0-288 h. Blood and liver tissue were extracted. Determination of serum transaminases and alkaline phosphatase activities was performed. Liver injury and regeneration were assessed with hematoxylin-eosin specimens, morphometric analysis, hepatic thymidine kinase assay and Ki-67 expression. Reverse transcription-polymerase chain reaction and immunohistochemical methods were used for assessment of VEGF isoforms and receptors differential expression. High activities of aspartate aminotransferase were observed at 24 and 36 h with another peak of activity at 192 h post administration. Alanine aminotransferase was highest at 36 h. Alkaline phosphatase was increased post 24 h being higher at 72,192 and 240 h. Centrilobular necrosis was observed at 48-72 h and thorough restoration of the liver microarchitecture was observed at 288 h. Liver regeneration lasted from 24-192 h according to the results from thymidine kinase activity and Ki-67 expression. VEGF and VEGF receptor-2 m-RNA levels presented with a three-peak pattern of expression at 12-24, 72-96 and 192-240 h post administration. Significant difference was noted between periportal and centrilobular immunohistochemical expression. VEGF proves to play a critical role during APAP-induced liver regeneration as it presents with three points of higher expression. The first two time points are associated with the initial inflammatory reaction to the noxious stimulus and the hepatocyte regenerative process where as the third one is indicative of the potential involvement of VEGF in processes of remodeling.

Liver resection for metastatic colorectal cancer in the age of neoadjuvant chemotherapy and bevacizumab

Hepatic metastases from colorectal carcinoma (CRC) were once thought to portend a uniformly grim outcome; however, improvements in chemotherapeutic and surgical approaches have led to significant advances as well as new clinical challenges. Some 60% of the 150,000 patients diagnosed with CRC each year in the United States will develop hepatic metastases. Only a fraction of these metastases are resectable at the time of presentation, but an increasing number of patients are able to undergo resection after neoadjuvant chemotherapy. Additionally, recent trials have demonstrated the efficacy of using chemotherapy with bevacizumab as first-line therapy for metastatic CRC, but how this treatment will affect surgical resection is unknown. Herein, we review the recent literature regarding neoadjuvant chemotherapy for hepatic metastases from CRC, discuss key aspects of the basic science of hepatic regeneration with regard to angiogenic mediators, and outline the key problems to be solved so that a rational strategy can be developed to treat patients with hepatic colorectal metastases in the age of neoadjuvant chemotherapy and antiangiogenic drugs.