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Krasimir Kolev  - - - 
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Krasimir Kolev

73 shared publications

Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary

63
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Distribution of Articles published per year 
(1987 - 2018)
Total number of journals
published in
 
30
 
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Article 0 Reads 0 Citations Neutrophil extracellular traps in thrombi retrieved during interventional treatment of ischemic arterial diseases Ádám Z. Farkas, Veronika J. Farkas, István Gubucz, László Sz... Published: 01 March 2019
Thrombosis Research, doi: 10.1016/j.thromres.2019.01.006
DOI See at publisher website
Article 3 Reads 0 Citations Functional cyclophilin D moderates platelet adhesion, but enhances the lytic resistance of fibrin Imre Varjú, Veronika Judit Farkas, László Kohidai, Laszlo Sz... Published: 29 March 2018
Scientific Reports, doi: 10.1038/s41598-018-23725-4
DOI See at publisher website PubMed View at PubMed ABS Show/hide abstract
In the course of thrombosis, platelets are exposed to a variety of activating stimuli classified as ‘strong’ (e.g. thrombin and collagen) or ‘mild’ (e.g. ADP). In response, activated platelets adhere to injured vasculature, aggregate, and stabilise the three-dimensional fibrin scaffold of the expanding thrombus. Since ‘strong’ stimuli also induce opening of the mitochondrial permeability transition pore (MPTP) in platelets, the MPTP-enhancer Cyclophilin D (CypD) has been suggested as a critical pharmacological target to influence thrombosis. However, it is poorly understood what role CypD plays in the platelet response to ‘mild’ stimuli which act independently of MPTP. Furthermore, it is unknown how CypD influences platelet-driven clot stabilisation against enzymatic breakdown (fibrinolysis). Here we show that treatment of human platelets with Cyclosporine A (a cyclophilin-inhibitor) boosts ADP-induced adhesion and aggregation, while genetic ablation of CypD in murine platelets enhances adhesion but not aggregation. We also report that platelets lacking CypD preserve their integrity in a fibrin environment, and lose their ability to render clots resistant against fibrinolysis. Our results indicate that CypD has opposing haemostatic roles depending on the stimulus and stage of platelet activation, warranting a careful design of any antithrombotic strategy targeting CypD.
Article 4 Reads 2 Citations Hyaluronic acid decreases the mechanical stability, but increases the lytic resistance of fibrin matrices Erzsébet Komorowicz, Nóra Balázs, Zoltán Varga, László Szabó... Published: 01 November 2017
Matrix Biology, doi: 10.1016/j.matbio.2016.12.008
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Article 5 Reads 0 Citations Structure and Function of Trypsin-Loaded Fibrinolytic Liposomes Anna Tanka-Salamon, Attila Bóta, András Wacha, Judith Mihály... Published: 03 July 2017
BioMed Research International, doi: 10.1155/2017/5130495
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Protease encapsulation and its targeted release in thrombi may contribute to the reduction of haemorrhagic complications of thrombolysis. We aimed to prepare sterically stabilized trypsin-loaded liposomes (SSLT) and characterize their structure and fibrinolytic efficiency. Hydrogenated soybean phosphatidylcholine-based SSLT were prepared and their structure was studied by transmission electron microscopy combined with freeze fracture (FF-TEM), Fourier transform infrared spectroscopy (FT-IR), and small-angle X-ray scattering (SAXS). Fibrinolytic activity was examined at 45, 37, or 24°C on fibrin or plasma clots with turbidimetric and permeation-driven lysis assays. Trypsin was shown to be attached to the inner surface of vesicles (SAXS and FF-TEM) close to the lipid hydrophilic/hydrophobic interface (FT-IR). The thermosensitivity of SSLT was evidenced by enhanced fibrinolysis at 45°C: time to reduce the maximal turbidity to 20% decreased by 8.6% compared to 37°C and fibrin degradation product concentration in the permeation lysis assay was 2-fold to 5-fold higher than that at 24°C. SSLT exerted its fibrinolytic action on fibrin clots under both static and dynamic conditions, whereas plasma clot dissolution was observed only in the permeation-driven assay. The improved fibrinolytic efficiency of SSLT under dynamic conditions suggests that they may serve as a novel therapeutic candidate for dissolution of intravascular thrombi, which are typically exposed to permeation forces.
Article 2 Reads 1 Citation Free Fatty Acids Modulate Thrombin Mediated Fibrin Generation Resulting in Less Stable Clots Anna Tanka-Salamon, Erzsébet Komorowicz, Laszlo Szabo, Kiril... Published: 12 December 2016
PLOS ONE, doi: 10.1371/journal.pone.0167806
DOI See at publisher website PubMed View at PubMed ABS Show/hide abstract
Upon platelet activation, free fatty acids are released at the stage of thrombus formation, but their effects on fibrin formation are largely unexplored. Our objective was to characterize the kinetic effects of fatty acids on thrombin activity, as well as the structural and mechanical properties of the resultant fibrin clots. Thrombin activity on fibrinogen was followed by turbidimetry and detailed kinetic characterization was performed using a fluorogenic short peptide substrate. The viscoelastic properties of fibrin were measured with rotatory oscillation rheometer, whereas its structure was analyzed with scanning electron microscopy (SEM). In turbidimetric assays of fibrin generation, oleate and stearate at physiologically relevant concentrations (60–600 μM) produced a bell-shaped inhibitory dose response, increasing 10- to 30-fold the time to half-maximal clotting. Oleate inhibited thrombin activity on a short peptide substrate according to a mixed-type inhibitor pattern (a 9-fold increase of the Michaelis constant, Km and a 20% decrease of the catalytic constant), whereas stearate resulted in only a minor (15%) drop in the catalytic constant without any change in the Km. Morphometric analysis of SEM images showed a 73% increase in the median fiber diameter in the presence of stearate and a 20% decrease in the presence of oleate. Concerning the viscoelastic parameters of the clots, storage and loss moduli, maximal viscosity and critical shear stress decreased by 32–65% in the presence of oleate or stearate, but loss tangent did not change indicating decreased rigidity, higher deformability and decreased internal resistance to shear stress. Our study provides evidence that free fatty acids (at concentrations comparable to those reported in thrombi) reduce the mechanical stability of fibrin through modulation of thrombin activity and the pattern of fibrin assembly.
Article 5 Reads 1 Citation Arginase activity, urea, and hydroxyproline concentration are reduced in keratoconus keratocytes Tanja Stachon, Krasimir Kolev, Zsuzsa Flaskó, Berthold Seitz... Published: 25 October 2016
European Journal of Applied Physiology, doi: 10.1007/s00417-016-3520-x
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