Endothelial hypoxic metabolism in carcinogenesis and dissemination: HIF-A isoforms are a NO metastatic phenomenon.

Tumor biology is a broad and encompassing field of research, particularly given recent demonstrations of the multicellular nature of solid tumors, which have led to studies of molecular and metabolic intercellular interactions that regulate cancer progression. Hypoxia is a broad stimulus that results in activation of hypoxia inducible factors (HIFs). Downstream HIF targets include angiogenic factors (e.g. vascular endothelial growth factor, VEGF) and highly reactive molecules (e.g. nitric oxide, NO) that act as cell-specific switches with unique spatial and temporal effects on cancer progression. The effect of cell-specific responses to hypoxia on tumour progression and spread, as well as potential therapeutic strategies to target metastatic disease, are currently under active investigation. Vascular endothelial remodelling events at tumour and metastatic sites are responsive to hypoxia, HIF activation, and NO signalling. Here, we describe the interactions between endothelial HIF and NO during tumor growth and spread, and outline the effects of endothelial HIF/NO signalling on cancer progression. In doing so, we attempt to identify areas of metastasis research that require attention, in order to ultimately facilitate the development of novel treatments that reduce or prevent tumour dissemination

Evaluation of the performance of self-healing concrete at small and large scale under laboratory conditions

HEALCON is an EU-FP7 project which aims to develop self-healing concrete to create durable and sustainable concrete structures. While during the first years of the project the self-healing materials (including the healing agents and suitable encapsulation methodologies) and monitoring techniques were designed and tested at lab-scale, large scale elements have been tested near the end of the project to verify the feasibility and efficiency of the self-healing concrete under conditions closer to reality. For this paper, two types of healing agents were investigated for use in mortar and concrete. The first type of healing agent studied was a coated superabsorbent polymer (C-SAP). It is known that the autogenous healing capacity is increased by incorporation of superabsorbent polymers (SAPs) in mortar/concrete. The agents present in the crack can absorb intruding water, swell and block the crack, leading to immediate sealing, but can also exude moisture to the surrounding concrete environment stimulating healing of the concrete by hydration of unreacted cement particles or by CaCO3 precipitation. The disadvantage of these SAPs in the fresh mortar/concrete mix is however that they absorb large quantities of mixing water, leading to unwanted effects (e.g. loss of workability and macro-pore formation). By coating of the SAPs, we want to eliminate this disadvantage. The fluid bed spraying of the different layers was applied by VTT. A second healing agent studied, is a biogenic healing agent, namely a Mixed Ureolytic Culture (MUC). This type of healing agent was developed by Avecom in order to reduce the cost associated with the production of pure bacterial strains. This mixed ureolytic culture is moreover self-protecting and does not need any further encapsulation. At first, the performance of the healing agents itself was evaluated. For the coated SAPs, the swelling performance and swelling rate were determined, showing that the coating can limit the uptake of water during the first 10-15 minutes. For the MUC, the ureolytic and CaCO3 precipitating capacity was determined, immediately after production of the MUC and after 3 months of storage. The results show the potential of these mixed cultures to be used as self-healing agent in mortar/concrete, but also show a decrease of their effectiveness with time. Subsequently, the healing agents were incorporated in mortar mixes at UGent. A dosage of 1 wt% relative to the cement content caused a large reduction of the mechanical properties of the mortar (up to ~ 50%), except for the coated SAP. The sealing efficiency was evaluated with the water flow test, as designed by one of the project partners in HEALCON. The performance of reference mixes was compared to that of self-healing mixes with SAP, coated SAP or MUC (+ urea). Results showed that for cracks with a width less than 0.150 mm, all mortars were sealed (almost) completely after storage for 28 days in wet-dry environment (12 h wet – 12 h dry) after crack creation. For cracks with a larger width, differences were noticed between the different specimens. Moreover, also the immediate sealing effect induced by the presence of SAPs could be noticed. It has to be noted however that the crack width plays an important role but is varying along the crack length (within a specimen) and between specimens, making the analysis more difficult. In order to extend the application to concrete, self-healing and reference reinforced concrete beams (2500 x 400 x 200 mm) were produced at the Danish Technological Institute. The self-healing concretes contained coated SAPs or MUC. Moreover, the beams were equipped with corrosion sensors that are connected to a wireless monitoring system, developed by the Technology-Transfer- Initiative at the University of Stuttgart. The multi reference electrodes (MuRE) were installed alongside the reinforcements and measure the corrosion potential at certain positions. Data is collected in sufficiently dense intervals by battery powered nodes that transmit the data wirelessly to a base station and further on to a database where it can be accessed through a web based application for data analysis over the internet. At the age of 28 days, three-point bending cracks up to 0.6 mm were created in the beams. Subsequently, the beams were regularly sprayed with water (four times one hour per day) for 6 weeks and afterwards, the beams were, once a week, exposed to 3 wt% NaCl solution for 24 h. Evaluation of the self-healing performance by microscopic analysis (crack microscopy and analysis of thin sections) showed that for the reference beam and beam with MUC no significant healing could be noticed (probably because of insufficient supply of nutrients for the bacteria). For the beams with coated SAPs, the smaller cracks (0.1 and 0.2 mm) were partly closed. Continuous corrosion monitoring showed corrosion in the reference and MUC beams already after the first exposure to NaCl solution. Onset of corrosion was delayed in the case the beams contained coated SAPs

Dietary nitrate increases arginine availability and protects mitochondrial complex I and energetics in the hypoxic rat heart

This is the final version. It was first published by Wiley in The Journal of Physiology at http://onlinelibrary.wiley.com/doi/10.1113/jphysiol.2014.275263/abstract.Hypoxic exposure is associated with impaired cardiac energetics in humans and altered mitochondrial function, with suppressed complex I-supported respiration, in rat heart. This response might limit reactive oxygen species (ROS) generation, but at the cost of impaired electron transport chain (ETC) activity. Dietary nitrate supplementation improves mitochondrial efficiency and can promote tissue oxygenation by enhancing blood flow. We therefore hypothesised that ETC dysfunction, impaired energetics and oxidative damage in the hearts of rats exposed to chronic hypoxia could be alleviated by sustained administration of a moderate dose of dietary nitrate. Male Wistar rats (n=40) were given water supplemented with 0.7 mmol/L NaCl (as control) or 0.7 mmol/L NaNO3, elevating plasma nitrate levels by 80%, and were exposed to 13% O2 (hypoxia) or normoxia (n=10 per group) for 14 days. Respiration rates, ETC protein levels, mitochondrial density, ATP content and protein carbonylation were measured in cardiac muscle. Complex I respiration rates and protein levels were 33% lower in hypoxic/NaCl rats compared with normoxic/NaCl controls. Protein carbonylation was 65% higher in hearts of hypoxic rats compared with controls, indicating increased oxidative stress, whilst ATP levels were 62% lower. Respiration rates, complex I protein and activity, protein carbonylation and ATP levels were all fully protected in the hearts of nitrate-supplemented hypoxic rats. Both in normoxia and hypoxia, dietary nitrate suppressed cardiac arginase expression and activity and markedly elevated cardiac L-arginine concentrations, unmasking a novel mechanism of action by which nitrate enhances tissue NO bioavailability. Dietary nitrate therefore alleviates metabolic abnormalities in the hypoxic heart, improving myocardial energetics

Suppression of erythropoiesis by dietary nitrate.

In mammals, hypoxia-triggered erythropoietin release increases red blood cell mass to meet tissue oxygen demands. Using male Wistar rats, we unmask a previously unrecognized regulatory pathway of erythropoiesis involving suppressor control by the NO metabolite and ubiquitous dietary component nitrate. We find that circulating hemoglobin levels are modulated by nitrate at concentrations achievable by dietary intervention under normoxic and hypoxic conditions; a moderate dose of nitrate administered via the drinking water (7 mg NaNO₃/kg body weight/d) lowered hemoglobin concentration and hematocrit after 6 d compared with nonsupplemented/NaCl-supplemented controls. The underlying mechanism is suppression of hepatic erythropoietin expression associated with the downregulation of tissue hypoxia markers, suggesting increased pO₂. At higher nitrate doses, however, a partial reversal of this effect occurred; this was accompanied by increased renal erythropoietin expression and stabilization of hypoxia-inducible factors, likely brought about by the relative anemia. Thus, hepatic and renal hypoxia-sensing pathways act in concert to modulate hemoglobin in response to nitrate, converging at an optimal minimal hemoglobin concentration appropriate to the environmental/physiologic situation. Suppression of hepatic erythropoietin expression by nitrate may thus act to decrease blood viscosity while matching oxygen supply to demand, whereas renal oxygen sensing could act as a brake, averting a potentially detrimental fall in hematocrit.This work was supported by British Heart Foundation Studentship FS/09/050 (to T.A.). A.J.M. thanks the Research Councils UK for supporting his academic fellowship and the WYNG Foundation of Hong Kong for support. J.L.G is supported by the European Union Framework 7 Inheritance project, R.S.J. is supported by a Wellcome Trust Principal research fellowship, and M.F. is supported by funds from the Faculty of Medicine, University of Southampton

Suppression of erythropoiesis by dietary nitrate

In mammals, hypoxia-triggered erythropoietin release increases red blood cell mass to meet tissue oxygen demands. Using male Wistar rats, we unmask a previously unrecognized regulatory pathway of erythropoiesis involving suppressor control by the NO metabolite and ubiquitous dietary component nitrate. We find that circulating hemoglobin levels are modulated by nitrate at concentrations achievable by dietary intervention under normoxic and hypoxic conditions; a moderate dose of nitrate administered via the drinking water (7 mg NaNO3/kg body weight/d) lowered hemoglobin concentration and hematocrit after 6 d compared with nonsupplemented/NaCl-supplemented controls. The underlying mechanism is suppression of hepatic erythropoietin expression associated with the downregulation of tissue hypoxia markers, suggesting increased pO2. At higher nitrate doses, however, a partial reversal of this effect occurred; this was accompanied by increased renal erythropoietin expression and stabilization of hypoxia-inducible factors, likely brought about by the relative anemia. Thus, hepatic and renal hypoxia-sensing pathways act in concert to modulate hemoglobin in response to nitrate, converging at an optimal minimal hemoglobin concentration appropriate to the environmental/physiologic situation. Suppression of hepatic erythropoietin expression by nitrate may thus act to decrease blood viscosity while matching oxygen supply to demand, whereas renal oxygen sensing could act as a brake, averting a potentially detrimental fall in hematocrit.—Ashmore, T., Fernandez, B. O., Evans, C. E., Huang, Y., Branco-Price, C., Griffin, J. L., Johnson, R. S., Feelisch, M., and Murray, A. J. Suppression of erythropoiesis by dietary nitrate

Screening for colorectal cancer leading into a new decade: the “Roaring ‘20s” for epigenetic biomarkers?

Colorectal cancer (CRC) has an important bearing (top five) on cancer incidence and mortality in the world. The etiology of sporadic CRC is related to the accumulation of genetic and epigenetic alterations that result in the appearance of cancer hallmarks such as abnormal proliferation, evasion of immune destruction, resistance to apoptosis, replicative immortality, and others, contributing to cancer promotion, invasion, and metastasis. It is estimated that, each year, at least four million people are diagnosed with CRC in the world. Depending on CRC staging at diagnosis, many of these patients die, as CRC is in the top four causes of cancer death in the world. New and improved screening tests for CRC are needed to detect the disease at an early stage and adopt patient management strategies to decrease the death toll. The three pillars of CRC screening are endoscopy, radiological imaging, and molecular assays. Endoscopic procedures comprise traditional colonoscopy, and more recently, capsule-based endoscopy. The main imaging modality remains Computed Tomography (CT) of the colon. Molecular approaches continue to grow in the diversity of biomarkers and the sophistication of the technologies deployed to detect them. What started with simple fecal occult blood tests has expanded to an armamentarium, including mutation detection and identification of aberrant epigenetic signatures known to be oncogenic. Biomarker-based screening methods have critical advantages and are likely to eclipse the classical modalities of imaging and endoscopy in the future. For example, imaging methods are costly and require highly specialized medical personnel. In the case of endoscopy, their invasiveness limits compliance from large swaths of the population, especially those with average CRC risk. Beyond mere discomfort and fear, there are legitimate iatrogenic concerns associated with endoscopy. The risks of perforation and infection make endoscopy best suited for a confirmatory role in cases where there are positive results from other diagnostic tests. Biomarker-based screening methods are largely non-invasive and are growing in scope. Epigenetic biomarkers, in particular, can be detected in feces and blood, are less invasive to the average-risk patient, detect early-stage CRC, and have a demonstrably superior patient follow-up. Given the heterogeneity of CRC as it evolves, optimal screening may require a battery of blood and stool tests, where each can leverage different pathways perturbed during carcinogenesis. What follows is a comprehensive, systematic review of the literature pertaining to the screening and diagnostic protocols used in CRC. Relevant articles were retrieved from the PubMed database using keywords including: “Screening”, “Diagnosis”, and “Biomarkers for CRC”. American and European clinical trials in progress were included as well.info:eu-repo/semantics/publishedVersio

Presurgical language fMRI: Mapping of six critical regions.

Language mapping is a key goal in neurosurgical planning. fMRI mapping typically proceeds with a focus on Broca's and Wernicke's areas, although multiple other language-critical areas are now well-known. We evaluated whether clinicians could use a novel approach, including clinician-driven individualized thresholding, to reliably identify six language regions, including Broca's Area, Wernicke's Area (inferior, superior), Exner's Area, Supplementary Speech Area, Angular Gyrus, and Basal Temporal Language Area. We studied 22 epilepsy and tumor patients who received Wada and fMRI (age 36.4[12.5]; Wada language left/right/mixed in 18/3/1). fMRI tasks (two × three tasks) were analyzed by two clinical neuropsychologists who flexibly thresholded and combined these to identify the six regions. The resulting maps were compared to fixed threshold maps. Clinicians generated maps that overlapped significantly, and were highly consistent, when at least one task came from the same set. Cases diverged when clinicians prioritized different language regions or addressed noise differently. Language laterality closely mirrored Wada data (85% accuracy). Activation consistent with all six language regions was consistently identified. In blind review, three external, independent clinicians rated the individualized fMRI language maps as superior to fixed threshold maps; identified the majority of regions significantly more frequently; and judged language laterality to mirror Wada lateralization more often. These data provide initial validation of a novel, clinician-based approach to localizing language cortex. They also demonstrate clinical fMRI is superior when analyzed by an experienced clinician and that when fMRI data is of low quality judgments of laterality are unreliable and should be withheld. Hum Brain Mapp 38:4239-4255, 2017. © 2017 Wiley Periodicals, Inc

Alternative and complementary therapies in osteoarthritis and cartilage repair

Osteoarthritis (OA) is the most common joint condition and, with a burgeoning ageing population, is due to increase in prevalence. Beyond conventional medical and surgical interventions, there are an increasing number of ‘alternative’ therapies. These alternative therapies may have a limited evidence base and, for this reason, are often only afforded brief reference (or completely excluded) from current OA guidelines. Thus, the aim of this review was to synthesize the current evidence regarding autologous chondrocyte implantation (ACI), mesenchymal stem cell (MSC) therapy, platelet-rich plasma (PRP), vitamin D and other alternative therapies. The majority of studies were in knee OA or chondral defects. Matrix-assisted ACI has demonstrated exceedingly limited, symptomatic improvements in the treatment of cartilage defects of the knee and is not supported for the treatment of knee OA. There is some evidence to suggest symptomatic improvement with MSC injection in knee OA, with the suggestion of minimal structural improvement demonstrated on MRI and there are positive signals that PRP may also lead to symptomatic improvement, though variation in preparation makes inter-study comparison difficult. There is variability in findings with vitamin D supplementation in OA, and the only recommendation which can be made, at this time, is for replacement when vitamin D is deplete. Other alternative therapies reviewed have some evidence (though from small, poor-quality studies) to support improvement in symptoms and again there is often a wide variation in dosage and regimens. For all these therapeutic modalities, although controlled studies have been undertaken to evaluate effectiveness in OA, these have often been of small size, limited statistical power, uncertain blindness and using various methodologies. These deficiencies must leave the question as to whether they have been validated as effective therapies in OA (or chondral defects). The conclusions of this review are that all alternative interventions definitely require clinical trials with robust methodology, to assess their efficacy and safety in the treatment of OA beyond contextual and placebo effects

Transcript and metabolite profiling of the adaptive response to mild decreases in oxygen concentration in the roots of arabidopsis plants

Oxygen can fall to low concentrations within plant tissues, either because of environmental factors that decrease the external oxygen concentration or because the movement of oxygen through the plant tissues cannot keep pace with the rate of oxygen consumption. Recent studies document that plants can decrease their oxygen consumption in response to relatively small changes in oxygen concentrations to avoid internal anoxia. The molecular mechanisms underlying this response have not been identified yet. The aim of this study was to use transcript and metabolite profiling to investigate the genomic response of arabidopsis roots to a mild decrease in oxygen concentrations. Arabidopsis seedlings were grown on vertical agar plates at 21, 8, 4 and 1 % (v/v) external oxygen for 0.5, 2 and 48 h. Roots were analysed for changes in transcript levels using Affymetrix whole genome DNA microarrays, and for changes in metabolite levels using routine GC-MS based metabolite profiling. Root extension rates were monitored in parallel to investigate adaptive changes in growth. The results show that root growth was inhibited and transcript and metabolite profiles were significantly altered in response to a moderate decrease in oxygen concentrations. Low oxygen leads to a preferential up-regulation of genes that might be important to trigger adaptive responses in the plant. A small but highly specific set of genes is induced very early in response to a moderate decrease in oxygen concentrations. Genes that were down-regulated mainly encoded proteins involved in energy-consuming processes. In line with this, root extension growth was significantly decreased which will ultimately save ATP and decrease oxygen consumption. This was accompanied by a differential regulation of metabolite levels at short- and long-term incubation at low oxygen. The results show that there are adaptive changes in root extension involving large-scale reprogramming of gene expression and metabolism when oxygen concentration is decreased in a very narrow range

Evidence for an anomalous like-sign dimuon charge asymmetry

We measure the charge asymmetry A of like-sign dimuon events in 6.1 fb(-1) of p (p) over bar collisions recorded with the D0 detector at a center-of-mass energy root s = 1.96 TeV at the Fermilab Tevatron collider. From A, we extract the like-sign dimuon charge asymmetry in semileptonic b-hadron decays: A(sl)(b) = -0.00957 +/- 0.00251 (stat) +/- 0.00146 (syst). This result differs by 3.2 standard deviations from the standard model prediction A(sl)(b)(SM) = (-2.3(0.6)(+0.5)) x 10(-4) and provides first evidence of anomalous CP violation in the mixing of neutral B mesons