Preservation of ancestral Cretaceous microflora recovered from a hypersaline oil reservoir.

Microbiology of a hypersaline oil reservoir located in Central Africa was investigated with molecular and culture methods applied to preserved core samples. Here we show that the community structure was partially acquired during sedimentation, as many prokaryotic 16S rRNA gene sequences retrieved from the extracted DNA are phylogenetically related to actual Archaea inhabiting surface evaporitic environments, similar to the Cretaceous sediment paleoenvironment. Results are discussed in term of microorganisms and/or DNA preservation in such hypersaline and Mg-rich solutions. High salt concentrations together with anaerobic conditions could have preserved microbial/molecular diversity originating from the ancient sediment basin wherein organic matter was deposited.

Role of angiogenic factors/cell adhesion markers in serum of cirrhotic patients with hepatopulmonary syndrome.

BACKGROUND & AIMS: Hepatopulmonary syndrome is a complication of chronic liver disease resulting in increased morbidity and mortality. It is caused by intrapulmonary vascular dilations and arteriovenous connections with devastating influence on gas exchange. The pathogenesis is not completely understood but evidence mounts for angiogenesis. Aims of this study were to identify angiogenic factors in serum of patients with hepatopulmonary syndrome and to study the possibility to predict its presence by these factors. METHODS: Multiplex assays were used to measure the concentration of angiogenic factors in patients with (n = 30) and without hepatopulmonary syndrome (n = 30). Diagnosis was based on the presence of gas exchange abnormality and intrapulmonary vasodilations according to published guidelines. RESULTS: Patients with and without hepatopulmonary syndrome had similar MELD scores (median: 11.2 vs. 11.6; P = 0.7), Child-Pugh score (P = 0.7) and PaCO2 values (median: 35 vs. 37; P = 0.06). PaO2 and P(A-a) O2 gradient were significantly different (respectively median of 80 vs. 86, P = 0.02; and 24 vs. 16, P = 0.004). Based on area under the curve (AUC) data and P-values, the best predictors were vascular cell adhesion molecule 1 (VCAM1) (AUC = 0.932; P < 0.001) and intercellular adhesion molecule 3 (ICAM3) (AUC = 0.741; P = 0.003). Combining these factors results in an AUC of 0.99 (after cross-validation still 0.99). CONCLUSIONS: VCAM1 and ICAM3 might be promising biomarkers for predicting hepatopulmonary syndrome. Combining these factors results in an AUC of 0.99 and a negative predictive value of 100%. Determining the concentration of these biomarkers might be a screening method to detect hepatopulmonary syndrome. The use of these biomarkers should be validated in larger groups of patients.

Evaluation of three activated carbons for combined adsorption and biodegradation of PCBs in aquatic sediment.

Three commercial granular activated carbons (GACs) were studied at laboratory scale with a view to the combined adsorption and biodegradation of PCBs in aquatic sediment. The three GACs, with contrasting physico-chemical characteristics, all show a high adsorption of PCBs and are thus capable of reducing aqueous pollutant concentrations. After a one-month incubation with 'Aroclor 1242'-spiked sediment, the three GACs were each colonized by a multispecies biofilm, although with different amounts of attached bacterial biomass and significantly distinct genetic bacterial communities; interestingly, the highest bacterial biomass was attached to the microporous vegetable GAC. The multispecies biofilms developed on the three GACs were all predominantly composed of Proteobacteria, especially the ß-, γ- and δ- subclasses, Chloroflexi and Acidobacteria, with genera previously found in environments containing PCBs or biphenyls, or able to perform cometabolic and direct PCB degradation. After an eight-month incubation under aerobic conditions, it was only the vegetable Picabiol GAC, with its low microporous volume, high total surface area and acidic property, that showed a significant (21%) reduction of tri- through penta-CB. Our results suggest that PCB bio-transformation by the bacterial community attached to the GAC is influenced by GAC's physico-chemical characteristics. Thus, a properly selected GAC could effectively be used to a) sequestrate and concentrate PCB from contaminated aquatic sediment and b) act as a support for efficient PCB degradation by an autochthonous bacterial biofilm.

Endoplasmic reticulum stress and angiogenesis: is there an interaction between them?

When cells are subjected to stress by changes in their extracellular environment, unfolded proteins accumulate in the endoplasmic reticulum (ER), causing ER stress. This initiates the unfolded protein response (UPR), a signal transduction cascade aiming at restoring cellular homeostasis. The UPR and angiogenesis are involved in the pathogenesis of many diseases such as cancer, pulmonary diseases and chronic liver diseases (CLDs) including alcoholic liver disease, non-alcoholic steatohepatitis and hepatitis B. This review summarizes the upcoming knowledge of the interaction between the UPR and angiogenesis in physiological angiogenesis and in different CLDs and other diseases.

The need for transparency and good practices in the qPCR literature.

Two surveys of over 1,700 publications whose authors use quantitative real-time PCR (qPCR) reveal a lack of transparent and comprehensive reporting of essential technical information. Reporting standards are significantly improved in publications that cite the Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) guidelines, although such publications are still vastly outnumbered by those that do not.

Role of vascular endothelial growth factor in the pathophysiology of nonalcoholic steatohepatitis in two rodent models.

UNLABELLED: The pathophysiology of nonalcoholic steatohepatitis (NASH) should be approached as a multifactorial process. In several stages of NASH, a link between disease progression and hepatic microvasculature changes can be made. In this study we investigated the role of angiogenesis in two mouse models for NASH, and the effect of a preventive and therapeutic antiangiogenic treatment in a diet-induced mouse model for NASH. Protein and RNA levels of angiogenic and inflammatory factors were significantly up-regulated in the liver of C56BL/6 and db/db mice with NASH at different timepoints. To examine the effect of angiogenic factors on the disease progression of NASH, a prevention and treatment study was set up, blocking the placental growth factor (PlGF) or vascular endothelial growth factor receptor 2 (VEGFR2). Our study showed that treatment prevents the progression of NASH by attenuating steatosis and inflammation, both in a preventive and therapeutic setting, thereby confirming the hypothesis that angiogenic factors play an early role in the disease progression from steatosis to NASH. Anti-PlGF (αPlGF) did not significantly improve liver histology. Vascular corrosion casting showed a more disrupted liver vasculature in mice with NASH compared to controls. Treatment with αVEGFR2 showed an improvement of the liver vasculature. Moreover, fat-laden primary hepatocytes treated with αVEGFR2 stored significantly less lipids. CONCLUSION: Our results demonstrate that there is an increased expression of angiogenic factors in the liver in different mouse models for NASH. We found that VEGFR2 blockage attenuates steatosis and inflammation in a diet-induced mouse model for NASH in a preventive and therapeutic setting. Our findings warrant further investigation of the role of angiogenesis in the pathophysiology in NASH.

The placental growth factor as a target against hepatocellular carcinoma in a diethylnitrosamine-induced mouse model.

BACKGROUND & AIMS: The placental growth factor (PlGF) is a member of the vascular endothelial growth factor (VEGF) family known to stimulate endothelial cell growth, migration and survival, attract angiocompetent macrophages, and determine the metastatic niche. Unlike VEGF, genetic studies have shown that PlGF is specifically involved in pathologic angiogenesis, thus its inhibition would not affect healthy blood vessels, providing an attractive drug candidate with a good safety profile. METHODS: We assess whether inhibition of PlGF could be used as a potential therapy against hepatocellular carcinoma (HCC), by using PlGF knockout mice and monoclonal anti-PlGF antibodies in a mouse model for HCC. In addition, the effect of PlGF antibodies is compared to that of sorafenib, as well as the combination of both therapies. RESULTS: We have found that both in a transgenic knockout model and in a treatment model, targeting PlGF significantly decreases tumor burden. This was achieved not only by inhibiting neovascularisation, but also by decreasing hepatic macrophage recruitment and by normalising the remaining blood vessels, thereby decreasing hypoxia and reducing the prometastatic potential of HCC. CONCLUSIONS: Considering the favourable safety profile and its pleiotropic effect on vascularisation, metastasis and inflammation, PlGF inhibition could become a valuable therapeutic strategy against HCC.

Anaerobic oxidation of methane in hypersaline cold seep sediments.

Life in hypersaline environments is typically limited by bioenergetic constraints. Microbial activity at the thermodynamic edge, such as the anaerobic oxidation of methane (AOM) coupled to sulphate reduction (SR), is thus unlikely to thrive in these environments. In this study, carbon and sulphur cycling was investigated in the extremely hypersaline cold seep sediments of Mercator mud volcano. AOM activity was partially inhibited but still present at salinity levels of 292 g L(-1) (c. eightfold sea water concentration) with rates of 2.3 nmol cm(-3) day(-1) and was even detectable under saturated conditions. Methane and evaporite-derived sulphate comigrated in the ascending geofluids, which, in combination with a partial activity inhibition, resulted in AOM activity being spread over unusually wide depth intervals. Up to 79% of total cells in the AOM zone were identified by fluorescence in situ hybridization (FISH) as anaerobic methanotrophs of the ANME-1. Most ANME-1 cells formed monospecific chains without any attached partner. At all sites, AOM activity co-occurred with SR activity and sometimes significantly exceeded it. Possible causes of these unexpected results are discussed. This study demonstrates that in spite of a very low energy yield of AOM, microorganisms carrying this reaction can thrive in salinity up to halite saturation.

Leptin-mediated reactive oxygen species production does not significantly affect primary mouse hepatocyte functions in vitro.

AIM: Direct and indirect effects of leptin on hepatic stellate cells (HSCs) have been documented in the literature, whereas little is known about leptin's actions on hepatocytes. Leptin mediates its profibrogenic and proinflammatory effects on HSCs in part through the production of intracellular reactive oxygen species (ROS). In this study, we focus our analysis on leptin-induced ROS production in hepatocytes. METHODS: The expression of leptin receptor isoforms on primary mouse liver cells was examined by real-time quantitative-PCR and western blotting. Cultures were exposed to leptin in combination with inhibitors for reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, MAP kinase/ERK kinase 1 (MEK1) or janus kinase 2 (JAK2). ROS levels were quantified by measuring fluorescence. The effects of leptin on hepatocyte functions and programmed cell death were evaluated by fluorescent or luminescent assays. RESULTS: Leptin induced ROS production in primary hepatocytes by 150-450%, compared with a 20-30% increase in HSCs and liver sinusoidal endothelial cells (LSECs). This ROS production could be inhibited by NADPH oxidase, MEK1 and JAK2 inhibitors. Western blotting indicated that mouse HSCs and LSECs mainly express short leptin receptor isoforms, whereas hepatocytes appeared to express both short and long isoform(s). Leptin-induced ROS production in db/db hepatocytes did not differ from wild-type mice. Finally, leptin had no negative influence on primary hepatocyte functions. CONCLUSION: Leptin induced higher ROS levels in primary hepatocytes than in LSECs and HSCs, depending on NADPH oxidase, MEK1 and JAK2 signalling but not on the long leptin receptor isoform. Furthermore, leptin exposure did not influence primary hepatocyte functionality negatively.

Inhibition of the placental growth factor decreases burden of cholangiocarcinoma and hepatocellular carcinoma in a transgenic mouse model.

OBJECTIVES: Hepatocellular carcinoma and cholangiocarcinoma form the majority of primary hepatic tumours and are the third most common cause of cancer-related deaths. These liver tumours rapidly outgrow their vascular supply and become hypoxic, resulting in the production of hypoxia inducible factors and triggering the angiogenic switch. Therefore, inhibiting angiogenesis has proven to be a valuable therapeutic strategy in hepatocellular carcinoma, yet less is known about its use in cholangiocarcinoma. In this study, we assess whether inhibiting the placental growth factor (PlGF) could offer a therapeutic option in mice with hepatocellular carcinoma and cholangiocarcinoma. PlGF is a homologue of the vascular endothelial growth factor, which is only involved in pathological angiogenesis, therefore, its inhibition does not induce adverse effects. METHODS: We have used a chemically induced transgenic mouse model in which both hepatocellular carcinoma and cholangiocarcinoma develop after 25 weeks and are treated with murine monoclonal antibodies targeting PlGF. RESULTS: This study has shown for the first time that inhibiting PlGF decreases the burden of cholangiocarcinoma, by affecting both angiogenesis and inflammation. CONCLUSION: The use of monoclonal antibodies targeting PlGF could thus offer a potential systemic treatment for patients who suffer from primary liver tumours.

Evaluation of inflammatory and angiogenic factors in patients with non-alcoholic fatty liver disease.

The liver is a major target of injury in obese patients. Non-alcoholic fatty liver disease (NAFLD) is present in 60-90% of obese Americans and can range from simple steatosis to the more severe non-alcoholic steatohepatitis (NASH). The onset of a chronic inflammatory reaction marks the progression from simple steatosis to NASH and the expansion of adipose tissue is strongly associated with angiogenesis. Therefore, we determined the serum concentration of inflammatory [tumor necrosis factor alpha (TNFα) and interleukin 6 (IL6)] and angiogenic [vascular endothelial growth factor A (VEGF)] cytokines and soluble VEGF receptors 1 and 2 (sVEGFR1, sVEGFR2) in the serum of an obese population with simple steatosis and NASH compared to healthy controls. Moreover, we determined the TNFα, IL6, VEGF, VEGFR1 and VEGFR2 gene expression in the liver of these simple steatosis and NASH patients. The population consisted of 30 obese patients, which were diagnosed with simple steatosis and 32 patients with NASH and compared to 30 age-and-sex matched healthy controls. Mean serum TNFα levels were elevated in the serum of simple steatosis and NASH patients compared to healthy controls, reaching significance in NASH patients. IL6 was significantly increased in simple steatosis and NASH patients compared to the healthy controls. VEGF levels were significantly elevated in patients with simple steatosis and borderline significantly elevated in NASH patients compared to the serum levels of healthy control subjects. The concentration of sVEGFR1 was significantly increased in serum of simple steatosis and NASH patients compared to controls. sVEGFR2 concentration was not significantly different in the three groups. TNFα mRNA expression was higher in NASH patients compared to simple steatosis patients. Hepatic gene expression of VEGF, VEGFR1 and VEGFR2 were slightly decreased in NASH patients compared to simple steatosis patients. These data indicate the involvement of inflammatory (TNFα and IL6), angiogenic (VEGF) cytokines and sVEGFR1 in the pathophysiology of NAFLD.

Precipitation of arsenic sulphide from acidic water in a fixed-film bioreactor.

Arsenic (As) is a toxic element frequently present in acid mine waters and effluents. Precipitation of trivalent arsenic sulphide in sulphate-reducing conditions at low pH has been studied with the aim of removing this hazardous element in a waste product with high As content. To achieve this, a 400m L fixed-film column bioreactor was fed continuously with a synthetic solution containing 100mg L(-1) As(V), glycerol and/or hydrogen, at pH values between 2.7 and 5. The highest global As removal rate obtained during these experiments was close to 2.5mg L(-1)h(-1). A switch from glycerol to hydrogen when the biofilm was mature induced an abrupt increase in the sulphate-reducing activity, resulting in a dramatic mobilisation of arsenic due to the formation of soluble thioarsenic complexes. A new analytical method, based on ionic chromatography, was used to evaluate the proportion of As present as thioarsenic complexes in the bioreactor. Profiles of pH, total As and sulphate concentrations suggest that As removal efficiency was linked to solubility of orpiment (As(2)S(3)) depending on pH conditions. Molecular fingerprints revealed fairly homogeneous bacterial colonisation throughout the reactor. The bacterial community was diverse and included fermenting bacteria and Desulfosporosinus-like sulphate-reducing bacteria. arrA genes, involved in dissimilatory reduction of As(V), were found and the retrieved sequences suggested that As(V) was reduced by a Desulfosporosinus-like organism. This study was the first to show that As can be removed by bioprecipitation of orpiment from acidic solution containing up to 100mg L(-1) As(V) in a bioreactor.

Effect of prolyl hydroxylase domain-2 haplodeficiency on the hepatocarcinogenesis in mice.

BACKGROUND & AIMS: The two major primary liver cancers in adults are hepatocellular carcinoma and cholangiocarcinoma. These tumors rapidly outgrow their vascular supply and become hypoxic, resulting in the production of hypoxia inducible factors. Recently, interest has grown in the regulators of these factors. Several reports have been published describing the role of prolyl hydroxylase domains--the key oxygen sensor responsible for the degradation of hypoxia inducible factors--tumor progression and vascularisation. The effect of prolyl hydroxylase domain 2 on the pathogenesis of liver cancer has never been studied. METHODS: A diethylnitrosamine-induced mouse model was used in this study, allowing primary hepatic tumors to occur as a result of chronic liver damage. Several parameters of prolyl hydroxylase domain 2-haplodeficient mice were compared to those of wild type mice, thereby focussing on the expression of angiogenic factors and on the hepatic progenitor cell activation and differentiation. RESULTS: This study shows that inhibiting prolyl hydroxylase domain 2 increases the hepatocarcinogenesis and stimulates the development of cholangiocarcinoma. Furthermore, PHD2 deficiency and the accompanying continuous HIF activation, selected for a more metastatic tumor phenotype. CONCLUSIONS: The effect of prolyl hydroxylase domain 2 deficiency on hepatocarcinogenesis hold a great potential for therapeutic intervention, since hypoxia and the selection for a more aggressive cholangiocarcinoma phenotype might also have a repercussion on patients receiving long-term treatment with anti-angiogenic compounds.

Inhibition of placental growth factor activity reduces the severity of fibrosis, inflammation, and portal hypertension in cirrhotic mice.

UNLABELLED: Placental growth factor (PlGF) is associated selectively with pathological angiogenesis, and PlGF blockade does not affect the healthy vasculature. Anti-PlGF is therefore currently being clinically evaluated for the treatment of cancer patients. In cirrhosis, hepatic fibrogenesis is accompanied by extensive angiogenesis. In this paper, we evaluated the pathophysiological role of PlGF and the therapeutic potential of anti-PlGF in liver cirrhosis. PlGF was significantly up-regulated in the CCl(4) -induced rodent model of liver cirrhosis as well as in cirrhotic patients. Compared with wild-type animals, cirrhotic PlGF(-/-) mice showed a significant reduction in angiogenesis, arteriogenesis, inflammation, fibrosis, and portal hypertension. Importantly, pharmacological inhibition with anti-PlGF antibodies yielded similar results as genetic loss of PlGF. Notably, PlGF treatment of activated hepatic stellate cells induced sustained extracellular signal-regulated kinase 1/2 phosphorylation, as well as chemotaxis and proliferation, indicating a previously unrecognized profibrogenic role of PlGF. CONCLUSION: PlGF is a disease-candidate gene in liver cirrhosis, and inhibition of PlGF offers a therapeutic alternative with an attractive safety profile.

Angiogenesis in chronic liver disease and its complications.

Nowadays, liver cancer, cirrhosis and other liver-related diseases are the fifth most common cause of mortality in the UK. Furthermore, chronic liver diseases (CLDs) are one of the major causes of death, which are still increasing year-on-year. Therefore, knowledge about the pathophysiology of CLDs and its complications is of uttermost importance. The goal of this review is to clarify the role of angiogenesis in the disease progression of various liver diseases. Looking closer at the pathophysiology of portal hypertension (PH), fibrosis, cirrhosis, non-alcoholic steatohepatitis (NASH) and hepatocellular carcinoma (HCC), we find that angiogenesis is a recurring factor in the disease progression. In PH, several factors involved in its pathogenesis, such as hypoxia, oxidative stress, inflammation and shear stress are potential mediators for the angiogenic response. The progression from fibrosis to cirrhosis, the end-point of CLDs, is distinguished by a prolonged inflammatory and fibrogenic process that leads to an abnormal angioarchitecture distinctive for cirrhosis. In several stages of NASH, a link might be made between the disease progression and hepatic microvasculature changes. HCC is one of the most vascular solid tumours in which angiogenesis plays an important role in its development, progression and metastasis. The close relationship between the progression of CLDs and angiogenesis emphasises the need for anti-angiogenic therapy as a tool for blocking or slowing down the disease progression. The fact that angiogenesis plays a pivotal role in CLDs gives rise to new opportunities for treating CLDs and its complications.