Center for Theoretical Problems of Physicochemical Pharmacology

Moscow, Russia

Center for Theoretical Problems of Physicochemical Pharmacology

Moscow, Russia
SEARCH FILTERS
Time filter
Source Type

Zakharova N.V.,National Research Center for Hematology | Artemenko E.O.,Center for Theoretical Problems of Physicochemical Pharmacology | Podoplelova N.A.,National Research Center for Hematology | Sveshnikova A.N.,Moscow State University | And 2 more authors.
PLoS ONE | Year: 2015

Coagulation factor XII (fXII) is important for arterial thrombosis, but its physiological activation mechanisms are unclear. In this study, we elucidated the role of platelets and plateletderived material in fXII activation. FXII activation was only observed upon potent platelet stimulation (with thrombin, collagen-related peptide, or calcium ionophore, but not ADP) accompanied by phosphatidylserine exposure and was localised to the platelet surface. Platelets from three patients with grey platelet syndrome did not activate fXII, which suggests that platelet-associated fXII-activating material might be released from α-granules. FXII was preferentially bound by phosphotidylserine-positive platelets and annexin V abrogated platelet-dependent fXII activation; however, artificial phosphotidylserine/phosphatidylcholine microvesicles did not support fXII activation under the conditions herein. Confocal microscopy using DAPI as a poly-phosphate marker did not reveal poly-phosphates associated with an activated platelet surface. Experimental data for fXII activation indicates an auto-inhibition mechanism (ki/ka = 180 molecules/platelet). Unlike surface-associated fXII activation, platelet secretion inhibited activated fXII (fXIIa), particularly due to a released C1-inhibitor. Platelet surface-associated fXIIa formation triggered contact pathway-dependent clotting in recalcified plasma. Computer modelling suggests that fXIIa inactivation was greatly decreased in thrombi under high blood flow due to inhibitor washout. Combined, the surface-associated fXII activation and its inhibition in solution herein may be regarded as a flow-sensitive regulator that can shift the balance between surface-associated clotting and plasma-dependent inhibition, which may explain the role of fXII at high shear and why fXII is important for thrombosis but negligible in haemostasis. © 2015 Zakharova et al.


Parunov L.A.,U.S. Food and Drug Administration | Parunov L.A.,LLC Hematological Corporation | Soshitova N.P.,LLC Hematological Corporation | Ovanesov M.V.,U.S. Food and Drug Administration | And 2 more authors.
Birth Defects Research Part C - Embryo Today: Reviews | Year: 2015

This review is focused on the epidemiology of venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), associated with pregnancy. Superficial vein thrombosis, a less hazardous and less studied type of thrombosis in pregnant women, is beyond the scope of this review. This study discusses the VTE incidence rate in women from developed countries for both antepartum and postpartum periods and for subpopulations of women affected by additional risk factors, such as thrombophilias, circulatory diseases, preeclampsia of varying degrees of severity, and Caesarean section. To minimize bias due to historical changes in medical and obstetric practices, lifestyle, diet, etc., this review is generally limited to relatively recent studies, i.e., those that cover the last 35 years. The absolute risk or incidence rate was used to ascertain risk of VTE associated with pregnancy. For the studies where the direct incidence rates of VTE were not reported, we calculated an estimate of the observed but not reported absolute incidence rates using the data presented in respective articles. © 2015 Wiley Periodicals, Inc.


PubMed | Moscow Institute of Physics and Technology, Center for Theoretical Problems of Physicochemical Pharmacology, Moscow State University and National Research Center for Hematology
Type: Journal Article | Journal: PloS one | Year: 2015

Coagulation factor XII (fXII) is important for arterial thrombosis, but its physiological activation mechanisms are unclear. In this study, we elucidated the role of platelets and platelet-derived material in fXII activation. FXII activation was only observed upon potent platelet stimulation (with thrombin, collagen-related peptide, or calcium ionophore, but not ADP) accompanied by phosphatidylserine exposure and was localised to the platelet surface. Platelets from three patients with grey platelet syndrome did not activate fXII, which suggests that platelet-associated fXII-activating material might be released from -granules. FXII was preferentially bound by phosphotidylserine-positive platelets and annexin V abrogated platelet-dependent fXII activation; however, artificial phosphotidylserine/phosphatidylcholine microvesicles did not support fXII activation under the conditions herein. Confocal microscopy using DAPI as a poly-phosphate marker did not reveal poly-phosphates associated with an activated platelet surface. Experimental data for fXII activation indicates an auto-inhibition mechanism (ki/ka = 180 molecules/platelet). Unlike surface-associated fXII activation, platelet secretion inhibited activated fXII (fXIIa), particularly due to a released C1-inhibitor. Platelet surface-associated fXIIa formation triggered contact pathway-dependent clotting in recalcified plasma. Computer modelling suggests that fXIIa inactivation was greatly decreased in thrombi under high blood flow due to inhibitor washout. Combined, the surface-associated fXII activation and its inhibition in solution herein may be regarded as a flow-sensitive regulator that can shift the balance between surface-associated clotting and plasma-dependent inhibition, which may explain the role of fXII at high shear and why fXII is important for thrombosis but negligible in haemostasis.


Parunov L.A.,Center for Theoretical Problems of Physicochemical Pharmacology | Fadeeva O.A.,National Research Center for Hematology | Balandina A.N.,Center for Theoretical Problems of Physicochemical Pharmacology | Soshitova N.P.,National Research Center for Hematology | And 7 more authors.
Journal of Thrombosis and Haemostasis | Year: 2011

Background:Tissue factor pathway inhibitor (TFPI) is a major regulator of clotting initiation and a promising target for pro- and anticoagulation therapy. The aptamer BAX499 (formerly ARC19499) is a high-affinity specific TFPI antagonist designed to improve hemostasis. However, it is not clear how stimulation of coagulation onset by inactivating TFPI will affect spatial and temporal clot propagation. Objective:To examine the BAX499 effect on clotting in a spatial, reaction-diffusion experimental system in comparison with that of recombinant activated factor VII (rVIIa). Methods: Clotting in plasma activated by immobilized tissue factor (TF) was monitored by videomicroscopy. Results:BAX499 dose-dependently improved coagulation in normal and hemophilia A plasma activated with TF at 2pmolem -2 by shortening lag time and increasing clot size by up to ∼2-fold. The effect was TFPI specific as confirmed by experiments in TFPI-depleted plasma with or without TFPI supplementation. Clotting improvement was half-maximal at 0.7nm of BAX499 and reached a plateau at 10nm, remaining there at concentrations up to 1000nm. The BAX499 effect decreased with TF surface density increase. RVIIa improved clotting in hemophilia A plasma activated with TF at 2 or 20pmolem -2, both by shortening lag time and increasing spatial velocity of clot propagation; its effects were strongly concentration dependent. Conclusions:BAX499 significantly improves spatial coagulation by inhibiting TFPI in a spatially localized manner that is different to that observed with rVIIa. © 2011 International Society on Thrombosis and Haemostasis.


Parunov L.A.,Center for Theoretical Problems of Physicochemical Pharmacology | Soshitova N.P.,National Research Center for Hematology | Fadeeva O.A.,National Research Center for Hematology | Balandina A.N.,Center for Theoretical Problems of Physicochemical Pharmacology | And 7 more authors.
Thrombosis Research | Year: 2014

Background In recent years, a number of tissue factor pathway inhibitor (TFPI) antagonists have been developed to serve as bypassing agents to improve hemostasis in hemophilia A. Since TFPI antagonists and FVIII concentrates are procoagulants, their combined effect on spatial clot formation could be potentially pro-thrombotic. Objective To investigate the cooperative effect of TFPI inhibition and supplementation of FVIII in hemophilia A in a spatial, reaction-diffusion experiment in vitro. Methods Plasma was collected at different time points from hemophilia A patients undergoing prophylaxis and was supplemented in vitro with TFPI inhibitor BAX499 (formerly ARC19499) at concentrations from 0 up to 600 nM. Clotting propagation in recalcified plasma activated by a surface with immobilized tissue factor (TF) was monitored by videomicroscopy. Results Increasing concentration of BAX499 improved coagulation for all hemophilia A plasma samples activated with TF at 1.6 pmole/m 2 by shortening lag time and increasing initial clot growth velocity and clot size. In contrast, plasma concentration of FVIII had little effect on lag time, but increased spatial clot growth velocity. There was a decrease in the BAX499 efficiency as FVIII concentration increased (lag time shortened by 50% if FVIII:C < 5%, but the effect was only 25% if FVIII:C > 30%). Conclusions The results indicate that BAX499 has an effect on clotting in hemophilia A plasma at low FVIII concentrations, however has little effect at high FVIII concentrations. © 2013 Elsevier Ltd. All rights reserved.


Artemenko E.O.,Center for Theoretical Problems of Physicochemical Pharmacology | Yakimenko A.O.,Center for Theoretical Problems of Physicochemical Pharmacology | Pichugin A.V.,Institute of Immunology FMBA of Russia | Ataullakhanov F.I.,Moscow Institute of Physics and Technology | Panteleev M.A.,Russian National Research Medical University
Biochemical Journal | Year: 2016

In resting platelets, adhesive membrane glycoproteins are attached to the cytoskeleton. On strong activation, phosphatidylserine(PS)-positive and -negative platelet subpopulations are formed. Platelet activation is accompanied by cytoskeletal rearrangement, although the glycoprotein attachment status in these two subpopulations is not clear. We developed a new, flow cytometry-based, single-cell approach to investigate attachment of membrane glycoproteins to the cytoskeleton in cell subpopulations. In PS-negative platelets, adhesive glycoproteins integrin αIIbβ3, glycoprotein Ib and, as shown for the first time, P-selectin were associated with the cytoskeleton. In contrast, this attachment was disrupted in PS-positive platelets; it was retained to some extent only in the small convex regions or 'caps'. It correlated with the degradation of talin and filamin observed only in PS-positive platelets. Calpain inhibitors essentially prevented the disruption of membrane glycoprotein attachment in PSpositive platelets, as well as talin and filamin degradation. With the suggestion that detachment of glycoproteins from the cytoskeleton may affect platelet adhesive properties, we investigated the ability of PS-positive platelets to resist shearinduced breakaway from the immobilized fibrinogen. Shear rates of 500/s caused PS-positive platelet breakaway, but their adhesion stability increased more than 10-fold after pretreatment of the platelets with calpain inhibitor. In contrast, the ability of PSpositive platelets to adhere to immobilized vonWillebrand's factor at 100/s was low, but this was not affected by the preincubation of platelets with a calpain inhibitor. Our data suggest that calpain-controlled detachment of membrane glycoproteins is a new mechanism that is responsible for the loss of ability of the procoagulant platelets to resist detachment from thrombi by high shear stress. © 2016 Authors; published by Portland Press Limited.


PubMed | Moscow Institute of Physics and Technology, Center for Theoretical Problems of Physicochemical Pharmacology, Institute of Immunology FMBA of Russia and Russian National Research Medical University
Type: Journal Article | Journal: The Biochemical journal | Year: 2016

In resting platelets, adhesive membrane glycoproteins are attached to the cytoskeleton. On strong activation, phosphatidylserine(PS)-positive and -negative platelet subpopulations are formed. Platelet activation is accompanied by cytoskeletal rearrangement, although the glycoprotein attachment status in these two subpopulations is not clear. We developed a new, flow cytometry-based, single-cell approach to investigate attachment of membrane glycoproteins to the cytoskeleton in cell subpopulations. In PS-negative platelets, adhesive glycoproteins integrin IIb3, glycoprotein Ib and, as shown for the first time, P-selectin were associated with the cytoskeleton. In contrast, this attachment was disrupted in PS-positive platelets; it was retained to some extent only in the small convex regions or caps. It correlated with the degradation of talin and filamin observed only in PS-positive platelets. Calpain inhibitors essentially prevented the disruption of membrane glycoprotein attachment in PS-positive platelets, as well as talin and filamin degradation. With the suggestion that detachment of glycoproteins from the cytoskeleton may affect platelet adhesive properties, we investigated the ability of PS-positive platelets to resist shear-induced breakaway from the immobilized fibrinogen. Shear rates of 500/s caused PS-positive platelet breakaway, but their adhesion stability increased more than 10-fold after pretreatment of the platelets with calpain inhibitor. In contrast, the ability of PS-positive platelets to adhere to immobilized von Willebrands factor at 100/s was low, but this was not affected by the preincubation of platelets with a calpain inhibitor. Our data suggest that calpain-controlled detachment of membrane glycoproteins is a new mechanism that is responsible for the loss of ability of the procoagulant platelets to resist detachment from thrombi by high shear stress.


Tarandovskiy I.D.,Center for Theoretical Problems of Physicochemical Pharmacology | Balandina A.N.,Center for Theoretical Problems of Physicochemical Pharmacology | Kopylov K.G.,National Research Center for Hematology | Konyashina N.I.,National Research Center for Hematology | And 3 more authors.
Thrombosis Research | Year: 2013

Background Hemophilia A (HA) patients with similar factor VIII levels can demonstrate varying bleeding tendencies. In particular, 10-15% of all severe HA patients (FVIII:C < 1 IU dL-1) do not require regular replacement therapy. Modern global coagulation assays can help to detect and study this "mild" bleeding phenotype. Here, we investigated the coagulation status of different bleeding phenotypes using various types of global coagulation assays. Materials and Methods Ten HA patients with severe phenotype and eleven patients with mild phenotypes were included in the study. For each patient, thromboelastography (TE), thrombodynamics (TD), and kaolin- or tissue factor-induced thrombin generation (TG) were measured. TG in platelet-rich plasma (PRP) was investigated using our original modification when the thrombin generation curve showed two peaks, previously shown to depend on platelet activity. We also utilized TG and TD with the addition of thrombomodulin. Results The second peak amplitude and ETP of PRP TG were the only parameters that were significantly higher in mild bleeders (peak 41.6 ± 3.5 nM, ETP 1966 ± 169 nM*min) than in patients with severe bleeding (peak 28.3 ± 3.3 nM, ETP 1359 ± 130 nM*min). Conclusions Our results suggest that severe and mild HA phenotypes could be distiguished by TG assay in PRP suggesting that difference in platelet activity can be involved in the phenotype formation. According to our previous results we can suppose that the mechanism of the phenotypic heterogeneity is linked with TG mediated by PS-expressing platelets. © 2013 Elsevier Ltd.


Shibeko A.M.,Center for Theoretical Problems of Physicochemical Pharmacology | Panteleev M.A.,Moscow Institute of Physics and Technology
Briefings in Bioinformatics | Year: 2016

Blood coagulation is a complex biochemical network that plays critical roles in haemostasis (a physiological process that stops bleeding on injury) and thrombosis (pathological vessel occlusion). Both up- and down-regulation of coagulation remain a major challenge for modern medicine, with the ultimate goal to correct haemostasis without causing thrombosis and vice versa. Mathematical/computational modelling is potentially an important tool for understanding blood coagulation disorders and their treatment. It can save a huge amount of time and resources, and provide a valuable alternative or supplement when clinical studies are limited, or not ethical, or technically impossible. This article reviews contemporary state of the art in the modelling of blood coagulation for practical purposes: to reveal the molecular basis of a disease, to understand mechanisms of drug action, to predict pharmacodynamics and drug-drug interactions, to suggest potential drug targets or to improve quality of diagnostics. Different model types and designs used for this are discussed. Functional mechanisms of procoagulant bypassing agents and investigations of coagulation inhibitors were the two particularly popular applications of computational modelling that gave non-trivial results. Yet, like any other tool, modelling has its limitations, mainly determined by insufficient knowledge of the system, uncertainty and unreliability of complex models. We show how to some extent this can be overcome and discuss what can be expected from the mathematical modelling of coagulation in not-so-far future. © The Author 2015. Published by Oxford University Press.


Yakimenko A.O.,HemaCore Hematological Corporation | Verholomova F.Y.,HemaCore Hematological Corporation | Kotova Y.N.,Center for Theoretical Problems of Physicochemical Pharmacology | Ataullakhanov F.I.,Moscow State University | Panteleev M.A.,Moscow State University
Biophysical Journal | Year: 2012

Blood platelets are anucleate cell fragments that play a critically important role in hemostasis and thrombosis. Platelets are activated with various agonists that allow them to aggregate, thus forming either hemostatic plugs or pathologic thrombi. Recent studies have revealed that at least two activated platelet subpopulations are formed upon potent stimulation of platelets with collagen and/or thrombin. One of these subpopulations consists of so-called coated platelets that express high levels of phosphatidylserine and retain α-granule proteins, including fibrinogen, on their surface. They also have reduced levels of the main aggregation receptor-activated glycoprotein IIb-IIIa, which might indicate a defect in their proaggregatory ability. In this study, the proaggregatory abilities of coated and noncoated platelets were assessed by means of light transmission aggregometry of suspensions with varying ratios of platelets from one subpopulation to those of a different subpopulation. A mathematical model of platelet aggregation in heterogeneous mixtures was developed to assist in the analysis of experimental data. Flow cytometry was employed to monitor platelet recruitment into aggregates and the ability of platelets to bind external fibrinogen. Finally, confocal microscopy was used to image coated platelets involved into aggregates formed by mechanical shaking. The obtained data revealed to our knowledge a novel mechanism regulating aggregate formation of platelet subpopulations: coated platelets cannot aggregate with each other but can be recruited into aggregates by noncoated platelets. © 2012 by the Biophysical Society.

Loading Center for Theoretical Problems of Physicochemical Pharmacology collaborators
Loading Center for Theoretical Problems of Physicochemical Pharmacology collaborators