Browsing by Subject "Fibrinogen"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    Fibrinogen in the glioblastoma microenvironment contributes to the invasiveness of brain tumor‐initiating cells
    (Wiley, 2021-09) Dzikowski, Lauren; Mirzaei, Reza; Sarkar, Susobhan; Kumar, Mehul; Bose, Pinaki; Bellail, Anita; Hao, Chunhai; Yong, V. Wee; Pathology and Laboratory Medicine, School of Medicine
    Glioblastomas (GBMs) are highly aggressive, recurrent, and lethal brain tumors that are maintained via brain tumor-initiating cells (BTICs). The aggressiveness of BTICs may be dependent on the extracellular matrix (ECM) molecules that are highly enriched within the GBM microenvironment. Here, we investigated the expression of ECM molecules in GBM patients by mining the transcriptomic databases and also staining human GBM specimens. RNA levels for fibronectin, brevican, versican, heparan sulfate proteoglycan 2 (HSPG2), and several laminins were high in GBMs compared to normal brain, and this was corroborated by immunohistochemistry. While fibrinogen transcript was at normal level in GBM, its protein immunoreactivity was prominent within GBM tissues. These ECM molecules in tumor specimens were in proximity to, and surrounding BTICs. In culture, fibronectin and pan-laminin induced the adhesion of BTICs onto the plastic substratum. However, fibrinogen increased the size of the BTIC spheres by facilitating the adhesive property, motility, and invasiveness of BTICs. These features of elevated invasiveness were corroborated in resected GBM specimens by the close proximity of fibrinogen with matrix metalloproteinase (MMP)-2 and-9, which are proteases implicated in metastasis. Moreover, the effect of fibrinogen-induced invasiveness was attenuated in BTICs where MMP-2 and -9 have been inhibited with siRNAs or pharmacological inhibitors. Our results implicate fibrinogen in GBM as a mediator of the invasive properties of BTICs, and as a target for therapy to reduce BTIC tumorigenecity.
  • Thumbnail Image
    Item
    Fluorescently conjugated annular fibrin clot for multiplexed real-time digestion analysis
    (Royal Society of Chemistry, 2021-12) Zeng, Ziqian; Nallan Chakravarthula, Tanmaye; Muralidharan, Charanya; Hall, Abigail; Linnemann, Amelia K.; Alves, Nathan J.; Emergency Medicine, School of Medicine
    Impaired fibrinolysis has long been considered as a risk factor for venous thromboembolism. Fibrin clots formed at physiological concentrations are promising substrates for monitoring fibrinolytic performance as they offer clot microstructures resembling in vivo. Here we introduce a fluorescently labeled fibrin clot lysis assay which leverages a unique annular clot geometry assayed using a microplate reader. A physiologically relevant fibrin clotting formulation was explored to achieve high assay sensitivity while minimizing labeling impact as fluorescence isothiocyanate (FITC)-fibrin(ogen) conjugations significantly affect both fibrin polymerization and fibrinolysis. Clot characteristics were examined using thromboelastography (TEG), turbidity, scanning electron microscopy, and confocal microscopy. Sample fibrinolytic activities at varying plasmin, plasminogen, and tissue plasminogen activator (tPA) concentrations were assessed in the present study and results were compared to an S2251 chromogenic assay. The optimized physiologically relevant clot substrate showed minimal reporter-conjugation impact with nearly physiological clot properties. The assay demonstrated good reproducibility, wide working range, kinetic read ability, low limit of detection, and the capability to distinguish fibrin binding-related lytic performance. In combination with its ease for multiplexing, it also has applications as a convenient platform for assessing patient fibrinolytic potential and screening thrombolytic drug activities in personalized medical applications.
  • Thumbnail Image
    Item
    Microplastic Effects on Thrombin-Fibrinogen Clotting Dynamics Measured via Turbidity and Thromboelastography
    (MDPI, 2022-12-13) Tran, Daniela Q.; Stelflug, Nathan; Hall, Abigail; Chakravarthula, Tanmaye Nallan; Alves, Nathan J.; Emergency Medicine, School of Medicine
    Micro/nanoplastics, whether manufactured or resulting from environmental degradation, can enter the body through ingestion, inhalation, or dermal pathways. Previous research has found that nanoplastics with diameters of ≤100 nm can translocate into the circulatory system in a dose-dependent manner and potentially impact thrombosis and hemostasis. To investigate the direct effects of microplastics on fibrin clot formation, a simplified ex vivo human thrombin/fibrinogen clot model was utilized. The 100 nm polystyrene particles (non-functionalized [nPS] and aminated [aPS]) were preincubated (0-200 µg/mL) with either thrombin or fibrinogen, and fibrin clot formation was characterized via turbidity and thromboelastography (TEG). When the particles were preincubated with fibrinogen, little effect was observed for aPS or nPS on turbidity or TEG up through 100 µg/mL. TEG results demonstrated a significant impact on clot formation rate and strength, in the case of nPS preincubated with thrombin exhibiting a significant dose-dependent inhibitory effect. In conclusion, the presence of microplastics can have inhibitory effects on fibrin clot formation that are dependent upon both particle surface charge and concentration. Negatively charged nPS exhibited the most significant impacts to clot strength, turbidity, and rate of fibrin formation when first incubated with thrombin, with its impact being greatly diminished when preincubated with fibrinogen in this simplified fibrin clot model.
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
    Viscoelastic Hemostatic Assays: A Primer on Legacy and New Generation Devices
    (MDPI, 2022-02-07) Volod, Oksana; Bunch, Connor M.; Zackariya, Nuha; Moore, Ernest E.; Moore, Hunter B.; Kwaan, Hau C.; Neal, Matthew D.; Al-Fadhl, Mahmoud D.; Patel, Shivani S.; Wiarda, Grant; Al-Fadhl, Hamid D.; McCoy, Max L.; Thomas, Anthony V.; Thomas, Scott G.; Gillespie, Laura; Khan, Rashid Z.; Zamlut, Mahmud; Kamphues, Peter; Fries, Dietmar; Walsh, Mark M.; Medicine, School of Medicine
    Viscoelastic hemostatic assay (VHAs) are whole blood point-of-care tests that have become an essential method for assaying hemostatic competence in liver transplantation, cardiac surgery, and most recently, trauma surgery involving hemorrhagic shock. It has taken more than three-quarters of a century of research and clinical application for this technology to become mainstream in these three clinical areas. Within the last decade, the cup and pin legacy devices, such as thromboelastography (TEG® 5000) and rotational thromboelastometry (ROTEM® delta), have been supplanted not only by cartridge systems (TEG® 6S and ROTEM® sigma), but also by more portable point-of-care bedside testing iterations of these legacy devices (e.g., Sonoclot®, Quantra®, and ClotPro®). Here, the legacy and new generation VHAs are compared on the basis of their unique hemostatic parameters that define contributions of coagulation factors, fibrinogen/fibrin, platelets, and clot lysis as related to the lifespan of a clot. In conclusion, we offer a brief discussion on the meteoric adoption of VHAs across the medical and surgical specialties to address COVID-19-associated coagulopathy.
  • Thumbnail Image
    Item
    Whole Blood, Fixed Ratio, or Goal-Directed Blood Component Therapy for the Initial Resuscitation of Severely Hemorrhaging Trauma Patients: A Narrative Review
    (MDPI, 2021-01-17) Walsh, Mark; Moore, Ernest E.; Moore, Hunter B.; Thomas, Scott; Kwaan, Hau C.; Speybroeck, Jacob; Marsee, Mathew; Bunch, Connor M.; Stillson, John; Thomas, Anthony V.; Grisoli, Annie; Aversa, John; Fulkerson, Daniel; Vande Lune, Stefani; Sjeklocha, Lucas; Tran, Quincy K.; Medicine, School of Medicine
    This narrative review explores the pathophysiology, geographic variation, and historical developments underlying the selection of fixed ratio versus whole blood resuscitation for hemorrhaging trauma patients. We also detail a physiologically driven and goal-directed alternative to fixed ratio and whole blood, whereby viscoelastic testing guides the administration of blood components and factor concentrates to the severely bleeding trauma patient. The major studies of each resuscitation method are highlighted, and upcoming comparative trials are detailed.