21 research outputs found

    Double-stranded DNA induces a prothrombotic phenotype in the vascular endothelium

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    Double-stranded DNA (dsDNA) constitutes a potent activator of innate immunity, given its ability to bind intracellular pattern recognition receptors during viral infections or sterile tissue damage. While effects of dsDNA in immune cells have been extensively studied, dsDNA signalling and its pathophysiological implications in non-immune cells, such as the vascular endothelium, remain poorly understood. The aim of this study was to characterize prothrombotic effects of dsDNA in vascular endothelial cells. Transfection of cultured human endothelial cells with the synthetic dsDNA poly(dA:dT) induced upregulation of the prothrombotic molecules tissue factor and PAI-1, resulting in accelerated blood clotting in vitro, which was partly dependent on RIG-I signalling. Prothrombotic effects were also observed upon transfection of endothelial cells with hepatitis B virus DNA-containing immunoprecipitates as well human genomic DNA. In addition, dsDNA led to surface expression of von Willebrand factor resulting in increased platelet-endothelium-interactions under flow. Eventually, intrascrotal injection of dsDNA resulted in accelerated thrombus formation upon light/dye-induced endothelial injury in mouse cremaster arterioles and venules in vivo. In conclusion, we show that viral or endogenous dsDNA induces a prothrombotic phenotype in the vascular endothelium. These findings represent a novel link between pathogen-and danger-associated patterns within innate immunity and thrombosis

    Inactivation of the tyrosine phosphatase SHP-2 drives vascular dysfunction in sepsis

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    Background: Sepsis, the most severe form of infection, involves endothelial dysfunction which contributes to organ failure. To improve therapeutic prospects, elucidation of molecular mechanisms underlying endothelial vascular failure is of essence. Methods: Polymicrobial contamination induced sepsis mouse model and primary endothelial cells incubated with sepsis serum were used to study SHP-2 in sepsis-induced endothelial inflammation. SHP-2 activity was assessed by dephosphorylation of pNPP, ROS production was measured by DCF oxidation and protein interactions were assessed by proximity ligation assay. Vascular inflammation was studied in the mouse cremaster model and in an in vitro flow assay. Findings: We identified ROS-dependent inactivation of the tyrosine phosphatase SHP-2 to be decisive for endothelial activation in sepsis. Using in vivo and in vitro sepsis models, we observed a significant reduction of endothelial SHP-2 activity, accompanied by enhanced adhesion molecule expression. The impaired SHP-2 activity was restored by ROS inhibitors and an IL-1 receptor antagonist. SHP-2 activity inversely correlated with the adhesive phenotype of endothelial cells exposed to IL-1β as well as sepsis serum via p38 MAPK and NF-κB. In vivo, SHP-2 inhibition accelerated IL-1β-induced leukocyte adhesion, extravasation and vascular permeability. Mechanistically, SHP-2 directly interacts with the IL-1R1 adaptor protein MyD88 via its tyrosine 257, resulting in reduced binding of p85/PI3-K to MyD88. Interpretation: Our data show that SHP-2 inactivation by ROS in sepsis releases a protective break, resulting in endothelial activation. Fund: German Research Foundation, LMU Mentoring excellence and FöFoLe Programme, Verein zur Förderung von Wissenschaft und Forschung, German Ministry of Education and Research. Keywords: Endothelial cells, IL-1β, MyD88, ROS, SHP-2, Sepsi

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    Stimulation of the EAAT4 glutamate transporter by SGK protein kinase isoforms and PKB

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    The serum and glucocorticoid inducible kinase (SGK) 1 is expressed in brain tissue and upregulated by ischemia, neuronal excitation, and dehydration. The present study has been performed to elucidate the expression of SGK1 in cerebellar Purkinje cells and to explore whether it influences the colocalized glutamate transporter EAAT4. Intense SGK1 staining was observed in Purkinje cells following 48 h of water deprivation. The kinase activates glutamate induced current (IGLU) in Xenopus oocytes heterologously expressing EAAT4, an effect mimicked by its isoforms SGK2, 3 and PKB. IGLU was decreased by the ubiquitin ligase Nedd4-2, an effect partially but not completely reversed by additional coexpression of the SGK kinase isoforms or PKB. According to immunohistochemistry EAAT4 protein abundance in the cell membrane was enhanced by SGK1 and decreased by Nedd4-2. In conclusion, SGK1 expression is upregulated by ischemia, excitation, and dehydration in cerebellar Purkinje cells. The upregulation of SGK1 may serve to stimulate EAAT4 and thus to reduce neuroexcitotoxicity

    Randomized double-blind placebo-controlled trial of bevacizumab therapy for radiation necrosis of the central nervous system

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    Purpose: To conduct a controlled trial of bevacizumab for the treatment of symptomatic radiation necrosis of the brain. Methods and Materials: A total of 14 patients were entered into a placebo-controlled randomized double-blind study of bevacizumab for the treatment of central nervous system radiation necrosis. All patients were required to have radiographic or biopsy proof of central nervous system radiation necrosis and progressive neurologic symptoms or signs. Eligible patients had undergone irradiation for head-and-neck carcinoma, meningioma, or low- to mid-grade glioma. Patients were randomized to receive intravenous saline or bevacizumab at 3-week intervals. The magnetic resonance imaging findings 3 weeks after the second treatment and clinical signs and symptoms defined the response or progression. Results: The volumes of necrosis estimated on T2-weighted fluid-attenuated inversion recovery and T1-weighted gadolinium-enhanced magnetic resonance imaging scans demonstrated that although no patient receiving placebo responded (0 of 7), all bevacizumab-treated patients did so (5 of 5 randomized and 7 of 7 crossover) with decreases in T2-weighted fluid-attenuated inversion recovery and T1-weighted gadolinium-enhanced volumes and a decrease in endothelial transfer constant. All bevacizumab-treated patients - and none of the placebo-treated patients - showed improvement in neurologic symptoms or signs. At a median of 10 months after the last dose of bevacizumab in patients receiving all four study doses, only 2 patients had experienced a recurrence of magnetic resonance imaging changes consistent with progressive radiation necrosis; one patient received a single additional dose of bevacizumab and the other patient received two doses. Conclusion: The Class I evidence of bevacizumab efficacy from the present study in the treatment of central nervous system radiation necrosis justifies consideration of this treatment option for people with radiation necrosis secondary to the treatment of head-and-neck cancer and brain cancer. © 2011 Elsevier Inc

    Differentiating among stages of cognitive impairment: Comparisons of versions two and three of the National Alzheimer- s Coordinating Center (NACC) Uniform Data Set (UDS) neuropsychological test battery

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    BackgroundNational Institute on Aging (NIA)- funded Alzheimer- s Disease Centers in the United States have been using a standardized neuropsychological test battery as part of the National Alzheimer- s Coordinating Center (NACC) Uniform Data Set (UDS) since 2005. Version 3 (V3) of the UDS was implemented in 2015 and included several changes to its neuropsychological battery, replacing the previous version [Version 2 (V2)]. The current study compares the V3 and V2 neuropsychological batteries with respect to their ability to distinguish among categories of cognitive impairment captured by the Clinical Dementia Rating (CDR) global scores representing either no cognitive impairment (CDR=0), questionable or mild cognitive impairment (CDR=0.5) or mild stage of dementia (CDR=1.0).MethodData from the NACC UDS V2 and V3 neuropsychological batteries were examined. There were 16,935 unique subjects from V2 and 5022 unique subjects from V3 aged 60 years and older with CDR global score - ¤ 1. To reduce the influence of practice effects, only data from their first assessment was used. To control for inequalities in sample sizes between V2 and V3, we identified an approximately equal number of subjects from V2 within each CDR group. Receiver Operating Characteristics Area under Curve (ROC- AUC) in differentiating stages of cognitive impairment were compared and optimal cut- points based on Youden- s J scores were calculated.ResultROC- AUCs from all of the V3 neuropsychological tests were comparable in their ability to differentiate CDR global scores with the corresponding tests in V2, despite the fact that V3 participants included more subjects at earlier stage of CDR 0.5. UDS V3 composite scores yielded similar ROC- AUCs to the best performing individual test within each domain, while the Montreal Cognitive Assessment (MoCA) total score yielded higher ROC- AUCs than any individual MoCA index scores. Racial differences in differentiating between CDR=0 and CDR=0.5 were also found.ConclusionA nonproprietary suite of neuropsychological tests in UDS V3 provided similar discriminative ability to tests in UDS V2 to distinguish categories of cognitive impairment. Optimal cut- points calculated in this study will be useful for clinical diagnosis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163944/1/alz040648.pd
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