• C1 inhibitor deficiency enhances contact pathway–mediated activation of coagulation and venous thrombosis 

      Grover, Steven P.; Kawano, Tomohiro; Wan, Jun; Tanratana, Pansakorn; Polai, Zsofia; Shim, Young J.; Snir, Omri; Brækkan, Sigrid Kufaas; Dhrolia, Sophia; Kasthuri, Rohan R.; Bendapudi, Pavan K.; McCrae, Keith R.; Wolberg, Alisa S.; Hansen, John Bjarne; Farkas, Henriette; Mackman, Nigel (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-11)
      C1 inhibitor (C1INH) is a multifunctional serine protease inhibitor that functions as a major negative regulator of several biological pathways, including the contact pathway of blood coagulation. In humans, congenital C1INH deficiency results in a rare episodic bradykinin-mediated swelling disorder called hereditary angioedema (HAE). Patients with C1INH deficiency–associated HAE (C1INH-HAE) have ...
    • Complement activation assessed by the plasma terminal complement complex and future risk of venous thromboembolism 

      Høiland, Ina Isabella; Liang, Robin Amanda; Brækkan, Sigrid Kufaas; Pettersen, Kristin; Ludviksen, Judith K; Latysheva, Nadezhda; Snir, Omri; Ueland, Thor; Hindberg, Kristian; Mollnes, Tom Eirik; Hansen, John-Bjarne (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-28)
      <i>Background</i>- It remains uncertain whether activation of the complement system, assessed by the soluble terminal C5b‐9 complement complex (plasma TCC), is associated with future risk of incident venous thromboembolism (VTE).<p> <p><i>Objectives</i>- To investigate the association between plasma levels of TCC and future risk of incident VTE in a nested case‐control study, and to explore ...
    • Complement factors B, D, C3bBbP and risk of future venous thromboembolism 

      Skjeflo, Espen Waage; Evensen, Line Holtet; Jensen, Søren Beck; Latysheva, Nadezhda; Michelsen, Annika Elisabet; Ueland, Thor; Brækkan, Sigrid Kufaas; Hindberg, Kristian Dalsbø; Snir, Omri; Mollnes, Tom Eirik; Hansen, John Bjarne (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-07)
      The complement system appears to be involved in the pathogenesis of venous thromboembolism (VTE).<p> <p>We investigated the association of complement factors (CF) B, D, and the alternative pathway convertase, C3bBbP, measured at inclusion, with the risk of future VTE in a nested case-control study; 380 VTE patients and 804 age- and sex-matched controls derived from the Tromsø study. Odds ratios ...
    • Elevated plasma concentration of complement factor C5 is associated with risk of future venous thromboembolism 

      Skjeflo, Espen Waage; Brækkan, Sigrid Kufaas; Ludviksen, Judith K; Snir, Omri; Hindberg, Kristian; Mollnes, Tom Eirik; Hansen, John-Bjarne (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-25)
      The role of complement in the pathogenesis of venous thromboembolism (VTE) is unclear. We wanted to investigate (1) whether plasma complement component C5 (C5) levels are influenced by genetic variants or chronic inflammation and (2) the association between plasma C5 and risk of future VTE in a nested case-control study of 415 patients with VTE and 848 age- and sex-matched controls derived from the ...
    • High Levels of Complement Activating Enzyme MASP-2 Are Associated With the Risk of Future Incident Venous Thromboembolism 

      Damoah, Christabel Esi; Snir, Omri; Hindberg, Kristian Dalsbø; Garred, Peter; Ludviksen, Judith K; Brækkan, Sigrid Kufaas; Morelli, Vania Maris; Mollnes, Tom Eirik; Hansen, John Bjarne (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-21)
      Background: Experimental studies have shown that the complement activating enzyme MASP-2 (mannose-binding lectin associated serine protease 2) exhibits a thrombin-like activity and that inhibition of MASP-2 protects against thrombosis. In this study, we investigated whether plasma MASP-2 levels were associated with risk of future venous thromboembolism (VTE) and whether genetic variants linked to ...
    • High plasma levels of C1-inhibitor are associated with lower risk of future venous thromboembolism 

      Grover, Steven P.; Snir, Omri; Hindberg, Kristian Dalsbø; Englebert, Tatianna M.; Brækkan, Sigrid Kufaas; Morelli, Vania Maris; Jensen, Søren Beck; Wolberg, Alisa S.; Mollnes, Tom Eirik; Ueland, Thor; Mackman, Nigel; Hansen, John Bjarne (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-31)
      Background - C1-inhibitor (C1INH) is a broad-acting serine protease inhibitor with anticoagulant activity. The impact of C1INH plasma levels within the normal physiological range on risk of venous thromboembolism (VTE) is unknown. We assessed the association of plasma C1INH levels and VTE risk and evaluated the impact of C1INH on thrombin and plasmin generation in ex vivo assays.<p> <p>Methods - ...
    • Label-free imaging on waveguide platform with enhanced resolution and contrast 

      Jayakumar, Nikhil; Dullo, Firehun Tsige; Dubey, Vishesh Kumar; Ahmad, Azeem; Cauzzo, Jennifer; Mazagao Guerreiro, Eduarda; Snir, Omri; Skalko-Basnet, Natasa; Agarwal, Krishna; Ahluwalia, Balpreet Singh (Conference object; Konferansebidrag, 2021)
      Chip-based Evanescent Light Scattering (cELS) utilizes the multiple modes of a high-index contrast optical waveguide for near-field illumination of unlabeled samples, thereby repositioning the highest spatial frequencies of the sample into the far-field. The multiple modes scattering off the sample with different phase differences is engineered to have random spatial distributions within the integration ...
    • A modified clot-based assay to measure negatively charged procoagulant phospholipids 

      Ramberg, Cathrine; Jamaly, Simin; Latysheva, Nadezhda; Wilsgård, line; Sovershaev, Timofey; Snir, Omri; Hansen, Jesper (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-29)
      Growing evidence supports a role for extracellular vesicles (EVs) in haemostasis and thrombosis due to exposure of negatively charged procoagulant phospholipids (PPL). Current commercial PPL-dependent clotting assays use chemically phospholipid depleted plasma to measure PPL activity. The purpose of our study was to modify the PPL assay by substituting the chemically phospholipid depleted plasma ...
    • Multi-moded high-index contrast optical waveguide for super-contrast high-resolution label-free microscopy 

      Jayakumar, Nikhil; Dullo, Firehun Tsige; Dubey, Vishesh Kumar; Ahmad, Azeem; Ströhl, Florian; Cauzzo, Jennifer; Mazagao Guerreiro, Eduarda; Snir, Omri; Skalko-Basnet, Natasa; Agarwal, Krishna; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-20)
      The article elucidates the physical mechanism behind the generation of superior-contrast and highresolution label-free images using an optical waveguide. Imaging is realized by employing a high index contrast multi-moded waveguide as a partially coherent light source. The modes provide near-field illumination of unlabeled samples, thereby repositioning the higher spatial frequencies of the ...
    • Optimized workflow to modify microRNA expression in primary human intravascular cells 

      Caglayan, Safak; Hansen, John Bjarne; Snir, Omri (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-15)
      Background - A comprehensive dissection of the role of microRNAs (miRNAs) in gene regulation and subsequent cell functions requires a specific and efficient knockdown or overexpression of the miRNA of interest; these are achieved by transfecting the cell of interest with a miRNA inhibitor or a miRNA mimic, respectively. Inhibitors and mimics of miRNAs with a unique chemistry and/or structural ...
    • Plasma levels of mannose-binding lectin and future risk of venous thromboembolism 

      Liang, Robin Amanda; Høiland, Ina Isabella; Ueland, Thor; Aukrust, Pål; Snir, Omri; Hindberg, Kristian; Brækkan, Sigrid Kufaas; Garred, Peter; Mollnes, Tom Eirik; Hansen, John-Bjarne (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-20)
      <i>Background</i> - Animal and observational studies have suggested a pathophysiological role for complement in venous thromboembolism (VTE), but the initiating mechanisms are unknown. Mannose‐binding lectin (MBL) bound to altered host cells leads to activation of the lectin complement pathway, and both high and low MBL levels have been implicated in the pathophysiology of cardiovascular ...
    • Plasma levels of P-selectin and future risk of incident venous thromboembolism 

      Swamy, Samantha; Ueland, Thor; Hansen, John Bjarne; Snir, Omri; Brækkan, Sigrid Kufaas (Journal article; Tidsskriftartikkel, 2023-05-12)
      Background - P-selectin levels are elevated following acute deep vein thrombosis and reported to predict recurrent venous thromboembolism (VTE) and cancer-associated VTE. Yet, it is unknown whether plasma P-selectin levels are associated with incident VTE.<p> <p>Objectives - We aimed to investigate the association between plasma P-selectin levels and risk of future incident VTE.<p> <p>Methods ...
    • Plasma levels of platelet-derived microvesicles are associated with risk of future venous thromboembolism 

      Snir, Omri; Wilsgård, line; Latysheva, Nadezhda; Ullsten-Wahlund, Casper; Brækkan, Sigrid Kufaas; Hindberg, Kristian Dalsbø; Hansen, John Bjarne (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-18)
      Background - Microvesicles (MVs) are small double‐membrane encapsulated particles shed from cells. Case‐control studies have reported elevated plasma levels of platelet‐derived MVs (PDMVs) in patients with venous thromboembolism (VTE). However, it is not known whether high PDMV levels is a risk factor or a consequence of the acute VTE event.<p> <p>Objectives - To investigate the association between ...
    • Plasma procoagulant phospholipid clotting time and venous thromboembolism risk 

      Ramberg, Cathrine; Wilsgård, line; Latysheva, Nadezhda; Brækkan, Sigrid Kufaas; Hindberg, Kristian; Sovershaev, Timofey; Snir, Omri; Hansen, John Bjarne (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-20)
      Background - Negatively charged procoagulant phospholipids, phosphatidylserine (PS) in particular, are vital to coagulation and expressed on the surface membrane of extracellular vesicles. No previous study has investigated the association between plasma procoagulant phospholipid clotting time (PPL<sub>CT</sub>) and future risk of venous thromboembolism (VTE).<p> <p>Objectives - To investigate the ...
    • A rapid, sensitive, and specific assay to measure TF activity based on chromogenic determination of thrombin generation 

      Østerud, Bjarne; Latysheva, Nadezhda; Schoergenhofer, Christian; Jilma, Bernd; Hansen, John-Bjarne; Snir, Omri (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-25)
      Background - Most tissue factor (TF) activity assays are based on measurement of factor X (FX) activation by TF in the presence of factor VII (FVII)/FVIIa. This requires long incubation, which may result in TF-independent activity of FX and inaccurate measurement of TF activity.<p> <p>Aim - To develop a sensitive and specific TF activity assay, which does not register a non-specific TF activity, ...
    • Rosuvastatin treatment decreases plasma procoagulant phospholipid activity after a VTE: A randomized controlled trial 

      Ramberg, Cathrine; Hindberg, Kristian; Biedermann, Joseph S.; Cannegieter, Suzanne C.; van der Meer, Felix J.; Snir, Omri; Leebeek, Frank W. G.; Kruip, Marieke J. H. A.; Hansen, John Bjarne; Lijfering, Willem M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-25)
      Background - Venous thromboembolism (VTE) is a frequent cardiovascular disease with severe complications, including recurrence and death. There is a great need for alternative prophylactic treatment options as anticoagulation is accompanied by increased bleeding risk. Statins are reported to reduce the risk of incident and recurrent VTE, but the mechanisms are elusive. Procoagulant phospholipids ...
    • Sustained and intermittent hypoxia differentially modulate primary monocyte immunothrombotic responses to IL-1β stimulation 

      Ullsten-Wahlund, Casper Jan Elis; Caglayan, Safak; Czarnewski, Paulo; Hansen, John Bjarne; Snir, Omri (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-11)
      Venous thromboembolism (VTE) is a leading cause of preventable deaths in hospitals, and its incidence is not decreasing despite extensive efforts in clinical and laboratory research. Venous thrombi are primarily formed in the valve pockets of deep veins, where activated monocytes play a crucial role in bridging innate immune activation and hemostatic pathways through the production of inflammatory ...