In Vivo Antithrombotic Effect of Triflavin, an Arg-Gly-Asp Containing Peptide on Platelet Plug Formation in Mesenteric Microvessels of Mice

1994 ◽  
Vol 72 (04) ◽  
pp. 617-621 ◽  
Author(s):  
Joen-Rong Sheu ◽  
Seh-Huang Chao ◽  
Mao-Hsiung Yen ◽  
Tur-Fu Huang
Keyword(s):  
Thrombus Formation ◽  
Antithrombotic Agent ◽  
In Vivo Models ◽  
Occlusion Time ◽  
Fibrinogen Binding ◽  
Acute Pulmonary Thromboembolism ◽  
Platelet Thrombus ◽  
Mesenteric Microvessels ◽  
Plug Formation

SummaryTriflavin, an Arg-Gly-Asp-containing snake venom peptide, inhibits platelet aggregation through the blockade of fibrinogen binding to the activated platelets. In this study, platelet thrombus formation was induced by irradiation of the mesenteric venules with filtered light in mice pretreated intravenously with fluorescein sodium. Electron microscopy reveals moderately damaged endothelial cells, as well as aggregates consisting almost exclusively of platelets with pseudopod formation, and degranulated appearance. Triflavin (10-20 µg/g) significantly prolonged the lag period of inducing platelet plug formation in mesenteric venules when it was intravenously infused. Triflavin (20 µg/g) prolonged the occlusion time about 2-fold (from control 112 ± 23 to 240 ± 47 s). Furthermore, PGE, briefly prolonged the occlusion time about 1.5-fold (from 105 ± 21 to 168 ± 20 s) when it was given by continuous infusion (40 µg/kg/min). On the other hand, triflavin was also effective in reducing the mortality of ADP-induced acute pulmonary thromboembolism in mice when administered intravenously at dose of 2-4 µg/g. Heparin (1.5 U/g) and indomethacin (200 µg/g) had no significant effect in prolonging the occlusion time or in reducing ADP-induced pulmonary embolism in mice. Therefore, triflavin is an effective antithrombotic agent in preventing the thromboembolism in these two in vivo models.

An Electron Microscopic Study of Platelet Thrombus Formation in the Rabbit with Particular Regard to 5-Hydroxytryptamine Release

1967 ◽  
Vol 18 (03/04) ◽  
pp. 592-604 ◽  
Author(s):  
H. R Baumgartner ◽  
J. P Tranzer ◽  
A Studer
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Vessel Wall ◽  
Thrombus Formation ◽  
Endothelial Damage ◽  
Electron Microscopic ◽  
Rabbit Ear ◽  
Basement Lamina ◽  
Platelet Thrombus

SummaryElectron microscopic and histologic examination of rabbit ear vein segments 4 and 30 min after slight endothelial damage have yielded the following findings :1. Platelets do not adhere to damaged endothelial cells.2. If the vessel wall is denuded of the whole endothelial cell, platelets adhere to the intimai basement lamina as do endothelial cells.3. The distance between adherent platelets as well as endothelial cells and intimai basement lamina measures 10 to 20 mµ, whereas the distance between aggregated platelets is 30 to 60 mµ.4. 5-hydroxytryptamine (5-HT) is released from platelets during viscous metamorphosis at least in part as 5-HT organelles.It should be noted that the presence of collagen fibers is not necessary for platelet thrombus formation in vivo.

The Effect of Agents which Modify Platelet Behaviour and of Magnesium Ions on Thrombus Formation In Vivo

1979 ◽  
Vol 42 (02) ◽  
pp. 603-610 ◽  
Author(s):  
J H Adams ◽  
J R A Mitchell
Keyword(s):  
Thrombus Formation ◽  
Cerebral Arteries ◽  
Magnesium Ions ◽  
Body Formation ◽  
Inflammatory Agent ◽  
Platelet Thrombus ◽  
Magnesium Salts ◽  
Higher Doses ◽  
Do So

SummaryThe ability of potential anti-thrombotic agents to modify platelet-thrombus formation in injured cerebral arteries in the rabbit was tested. Low doses of heparin were without effect, while higher doses produced variable suppression of white body formation but at the expense of bleeding. Aspirin did not inhibit white body formation but another non-steroid anti-inflammatory agent, flurbiprofen was able to do so, as was the anti-gout agent, sulphinpyrazone. Magnesium salts both topically and parenterally, suppressed thrombus formation and increased the concentration of ADP which was required to initiate thrombus production at minor injury sites.

scholarly journals Antithrombotic effect of a monoclonal antibody to the platelet glycoprotein IIb/IIIa receptor in an experimental animal model

Blood ◽  
1986 ◽  
Vol 68 (3) ◽  
pp. 783-786 ◽  
Author(s):  
BS Coller ◽  
JD Folts ◽  
LE Scudder ◽  
SR Smith
Keyword(s):  
Monoclonal Antibody ◽  
Animal Model ◽  
Platelet Aggregation ◽  
Ex Vivo ◽  
Thrombus Formation ◽  
Platelet Glycoprotein ◽  
Antithrombotic Effect ◽  
Antithrombotic Agent ◽  
Antithrombotic Effects ◽  
Platelet Thrombus

A murine monoclonal antibody directed at the platelet glycoprotein IIb/IIIa complex, which blocks platelet aggregation ex vivo, was tested for its antithrombotic effects in an established animal model of acute platelet thrombus formation in partially stenosed arteries. Infusion of 0.7 to 0.8 mg/kg of the F(ab')2 fragment of the antibody completely blocked new thrombus formation despite multiple provocations, making it the most potent antithrombotic agent tested in this model.

scholarly journals Accumulation of Tissue Factor into Developing Thrombi In Vivo Is Dependent upon Microparticle P-Selectin Glycoprotein Ligand 1 and Platelet P-Selectin

2003 ◽  
Vol 197 (11) ◽  
pp. 1585-1598 ◽  
Author(s):  
Shahrokh Falati ◽  
Qingde Liu ◽  
Peter Gross ◽  
Glenn Merrill-Skoloff ◽  
Janet Chou ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Blood Coagulation ◽  
Thrombus Formation ◽  
Recipient Mouse ◽  
Wild Type ◽  
Activated Platelets ◽  
Injury Model ◽  
Platelet Thrombus ◽  
Flowing Blood

Using a laser-induced endothelial injury model, we examined thrombus formation in the microcirculation of wild-type and genetically altered mice by real-time in vivo microscopy to analyze this complex physiologic process in a system that includes the vessel wall, the presence of flowing blood, and the absence of anticoagulants. We observe P-selectin expression, tissue factor accumulation, and fibrin generation after platelet localization in the developing thrombus in arterioles of wild-type mice. However, mice lacking P-selectin glycoprotein ligand 1 (PSGL-1) or P-selectin, or wild-type mice infused with blocking P-selectin antibodies, developed platelet thrombi containing minimal tissue factor and fibrin. To explore the delivery of tissue factor into a developing thrombus, we identified monocyte-derived microparticles in human platelet–poor plasma that express tissue factor, PSGL-1, and CD14. Fluorescently labeled mouse microparticles infused into a recipient mouse localized within the developing thrombus, indicating that one pathway for the initiation of blood coagulation in vivo involves the accumulation of tissue factor– and PSGL-1–containing microparticles in the platelet thrombus expressing P-selectin. These monocyte-derived microparticles bind to activated platelets in an interaction mediated by platelet P-selectin and microparticle PSGL-1. We propose that PSGL-1 plays a role in blood coagulation in addition to its known role in leukocyte trafficking.

Abstract 1033: Simultaneous Clot-targeted Factor Xa Inhibition And Selective Blockade Of Activated GPIIb/IIIa On Platelets Results In Delayed But Potent Antithrombotic Effects Without Bleeding Time Prolongation.

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Christoph E Hagemeyer ◽  
Steffen U Eisenhardt ◽  
Nicole Bassler ◽  
Patrick Stoll ◽  
Meike Schwarz ◽  
...  
Keyword(s):  
Bleeding Time ◽  
Specific Binding ◽  
Factor Xa ◽  
Single Chain ◽  
Occlusion Time ◽  
Selective Blockade ◽  
Thrombosis Model ◽  
Fibrinogen Binding ◽  
Antithrombotic Effects

Background: We generated phage-display-derived anti-GPIIb/IIIa single-chain antibodies (e.g. scFv SCE5) that specifically bind to the activated GPIIb/IIIa only and thus specifically block activated platelets only. ScFv SCE5 demonstrates strong antithrombotic potency, comparable to the conformation-unspecific blockers tirofiban and eptifibatide. In contrast bleeding times were not prolonged with scFv SCE5. Here we now use the possibility to add effector molecules using molecular biology methods. The highly potent anticoagulant TAP (tick anticoagulant peptide), which is a direct factor Xa (fXa) inhibitor, was used as an effector molecule. Methods and Results: We genetically fused the activation-specific scFv with TAP, expressed the constructs in E.coli and purified the 39 kDa protein via its Histag binding to Nickel beads. Specific binding of the fusion molecules MA2/SCE5-TAP and strong inhibition of fibrinogen binding was proven in flow cytometry; anti-fXa activity was demonstrated in chromogenic assays. In vivo anticoagulative efficiency was determined by Doppler-flow in a ferric chloride-induced carotid artery thrombosis model in mice. Prolongation in occlusion time with SCE5-TAP was significantly stronger compared to SCE5 alone, recombinant TAP, non-binding mut-scFv-TAP as well as the clinical used drugs enoxaparine and eptifibatide. In contrast to the other anticoagulants tested, bleeding time was not prolonged by SCE5-TAP. Flow experiments studying platelet adhesion on collagen revealed a possible mechanism for the unique finding of a fully normal bleeding time: LIBS exposure on adhering platelets and as such the anticoagulative targeting potency of SCE5-TAP was delayed until considerable layers of platelets were deposited. Conclusions: The combination of activation-specific GPIIb/IIIa blockade and fXa inhibition in one clot-targeted molecule further improves in-vivo antithrombotic efficiency without causing any bleeding time prolongation. The delay of the observed targeting effect may allow a sealing of injuries with platelet layers but may be in time for the prevention of occlusive platelet aggregates. The described blockers represent a new type of highly selective drugs that warrant further clinical development.

Effect Of Selective Inhibition Of Platelet Thromboxane On Platelet-Vessel Wall Interaction In Vivo

1981 ◽  
Author(s):  
Y C Chen ◽  
K K Wu ◽  
E R Hall ◽  
D L Venton ◽  
G C Le Breton
Keyword(s):  
Vessel Wall ◽  
Platelet Reactivity ◽  
Thrombus Formation ◽  
Balloon Catheter ◽  
Specific Inhibitor ◽  
Constant Infusion ◽  
Catheter Technique ◽  
Platelet Thrombus ◽  
Platelet Accumulation

It is well recognized that thromboxane A2(TXA2) plays an important role in platelet reactivity. To determine the role of TXA2 in platelet-vessel wall (P-V) interaction, the effect of 1-benzylimidazole (1-BI), a specific inhibitor of thromboxane synthetase, and 13-azaprostanoic acid (APA), a TXA2 antagonist, on platelet thrombus formation was evaluated in vivo in NZW male rabbits using the autologous indium-111 (111In) labeled platelet technique. Rabbits were treated with intravenous 1-BI or APA or vehicles. After injection of autologous 111In-platelets, de-endothelialization of the abdominal aorta was created by a balloon catheter technique. At 3 hrs, blood samples were obtained and the animals were sacrificed. The aortae were removed and the injured and uninjured segments were dissected. Radioactivity counts and dry weight of the tissues and blood were determined. The vascular radioactivity counts were converted to platelet numbers by using a standard linear calibration curve. As small numbers of platelets adhered to normal vessel wall nonspecifically, this number was subtracted to obtain specific platelet accumulation at the injured sites. 1-BI at 10mg/kg reduced the specific platelet accumulation significantly (n=5, 12.3±S.D.I.5×106 pl/gm tissue; p<0.01) when compared with the controls (n=10, 33.0±5.1×106 pl/gm tissue). Platelet accumulation was further reduced by increasing the dosage to 30mg/kg. By contrast, APA injection (10mg/kg) had no significant effect. However, when APA was given by constant infusion at 250μg/kg/min 1 hr prior to injury, the APA-treated animals had an 80% reduction of platelet accumulation relative to controls. These findings indicate that TXA2 plays an important role in P-V interaction and specific inhibition of TXA2 appears to be efficacious in eliminating platelet thrombus formation.

scholarly journals Susceptibility to Thrombosis in Normal Young, Aging, Cortisone-treated, Heparinized and X-irradiated Hamsters as Tested by Topical Application of Thrombin

Blood ◽  
1955 ◽  
Vol 10 (8) ◽  
pp. 831-840 ◽  
Author(s):  
HERBERT J. BERMAN ◽  
GEORGE P. FULTON ◽  
BRENTON H. LUTZ ◽  
DAVID L. PIERCE
Keyword(s):  
Thrombus Formation ◽  
Blood Platelets ◽  
Cheek Pouch ◽  
Whole Body ◽  
Minimum Concentration ◽  
In Vivo Test ◽  
Platelet Concentration ◽  
X Irradiation ◽  
Platelet Thrombus

Abstract 1. Thrombin applied topically to the everted cheek pouch of the hamster produced platelet and not red thrombi in exposed, uninjured blood vessels with circulating blood. Red thrombi were produced in stagnant blood. Thrombus formation occurred in the venules for the most part and seldom in arterioles or capillaries. 2. An in vivo test for platelet thrombus susceptibility, based on the thrombin reaction and the resistance of the hamster to thrombosis, has been described. 3. Thrombus susceptibility, measured by the thrombin test, increased with age and during cortisone treatment, and decreased after heparin injection and following large doses of whole body x-irradiation. 4. The thrombin susceptibility test could be correlated with the platelet count in x-irradiated hamsters, showing a relatively critical minimum concentration of blood platelets (100,000/cu.mm.) required for platelet thrombosis. 5. The relationship of platelet concentration to platelet thrombus formation and predisposition to hemorrhage has been discussed.

The Influence Of Materials And Platelet Inhibition On The Thrombogenicity Of Arterial Grafts In Man

1981 ◽  
Author(s):  
C N McCollum ◽  
H C Norcott ◽  
R J Hawker ◽  
M Goldman ◽  
Z Drolc ◽  
...  
Keyword(s):  
Thrombus Formation ◽  
Platelet Inhibition ◽  
Double Blind ◽  
Arterial Grafts ◽  
Vein Grafts ◽  
Effect Of Therapy ◽  
Autogenous Vein ◽  
Platelet Thrombus ◽  
Platelet Accumulation

Prosthetic arterial grafts often thrombose when used to bypass diseased small arteries due to the deposition of laminated platelet thrombus. The rate of lll-Indium labelled platelet accumulation on autogenous vein, polytetra- fluoroethylene (PTFE, Gore-Tex) and double velour Dacron (Microvel) has been investigated in patients and the influence of aspirin and dipyridamole (ASA/DPM) evaluated.Two days before surgery 40 patients undergoing femoro-popliteal bypass were started randomly and double blind, on either ASA 300 mgm + DPM 75 mgm tds or placebo. One week postoperatively autologous 111-Indium labelled platelets were injected and isotope emissions over the graft and contralateral leg counted for 7 days. Graft thrombogenicity was calculated as the daily rise in the ratio of counts, graft/contralateral thigh.Three placebo and one ASA/DPM prosthetic grafts occluded prior to study. Thrombogenicity (mean ± SEM) was greatest in the Dacron grafts at 0.22 ± 0.03 on placebo (n=7) and 0.16 ± 0.03 on ASA/DPM (n=5) (p < 0.05). The effect of therapy however, was most striking in reducing thrombogenicity of PTFE grafts from 0.17 ± 0.03 (n=4) to 0.06 ± 0.01 (n=7) (p < 0.02). The thrombogenicity of 0.03 ± 0.005 was so low in the 13 vein grafts that the effect of therapy could not be determined.The 111-Indium platelet technique described may be used to quantitate in vivo platelet deposition. In man the combination of ASA/DPM reduced the rate of thrombus formation on prosthetic materials. PTFE grafts with ASA/DPM therapy most nearly approach the low thrombogenicity of vein.

Effect of the PlA2 alloantigen on the function of β3-integrins in platelets

Blood ◽  
2001 ◽  
Vol 97 (10) ◽  
pp. 3093-3099 ◽  
Author(s):  
Joel S. Bennett ◽  
Francesca Catella-Lawson ◽  
Andrew R. Rut ◽  
Gaston Vilaire ◽  
Weiwei Qi ◽  
...  
Keyword(s):  
Risk Factor ◽  
B Lymphocytes ◽  
Statistical Difference ◽  
Thrombus Formation ◽  
Coronary Thrombosis ◽  
Fibrinogen Binding ◽  
Β3 Integrin ◽  
Platelet Thrombus ◽  
Adhesion Of Platelets ◽  
Dissociation Constant Kd

Abstract The polymorphism responsible for the PlA2 alloantigen on the β3-component of β3-containing integrins is reported to be a risk factor for coronary thrombosis. This study examined the effect of PlA2 on the function of β3-integrins using platelets from subjects homozygous and heterozygous for PlA1 and PlA2. There was overlap in the distribution of the dissociation constant (Kd) and maximum fibrinogen binding (Bmax) values for fibrinogen binding to αIIbβ3 on platelets from PlA1 and PlA2 homozygotes and PlA1/PlA2 heterozygotes. However, whereas there was no statistical difference in these values for the PlA1homozygotes and PlA2 heterozygotes, the Kd for the PlA2 homozygotes was significantly lower than that for the PlA1/PlA2 heterozygotes, but was not statistically different from that for the PlA1 homozygotes. No differences were detected in ADP sensitivity between platelets from PlA1 homozygotes and PlA1/PlA2heterozygotes, in the IC50 for RGDS inhibition of fibrinogen binding to αIIbβ3, in the αvβ3-mediated adhesion of platelets to osteopontin and vitronectin, and in the phorbol ester-stimulated adhesion to fibrinogen of B lymphocytes expressing αIIbβ3 containing either the PlA1 or the PlA2 polymorphism. Finally, no differential effects of PlA2 on turbidometric platelet aggregation, platelet secretion, or platelet thrombus formation were found as measured in the PFA-100. Because no differences were detected in the ability of β3-integrins to interact with ligands based on the presence or absence of the PlA2 polymorphism, the results suggest that factors unrelated to β3-integrin function may account for the reported association of the PlA2 allele with coronary thrombosis.

scholarly journals Antiplatelet Activity ofMorus albaLeaves Extract, Mediated via Inhibiting Granule Secretion and Blocking the Phosphorylation of Extracellular-Signal-Regulated Kinase and Akt

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Dong-Seon Kim ◽  
Hyun Dong Ji ◽  
Man Hee Rhee ◽  
Yoon-Young Sung ◽  
Won-Kyung Yang ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Thrombus Formation ◽  
Underlying Mechanism ◽  
Serotonin Release ◽  
Platelet Activity ◽  
Antithrombotic Agent ◽  
Serotonin Secretion ◽  
Venous Shunt ◽  
Granule Secretion

Ethnopharmacological Relevance.Morus albaL. leaves (MAE) have been used in fork medicine for the treatment of beriberi, edema, diabetes, hypertension, and atherosclerosis. However, underlying mechanism of MAE on cardiovascular protection remains to be elucidated. Therefore, we investigated whether MAE affect platelet aggregation and thrombosis.Materials and Methods. The anti-platelet activity of MAE was studied using rat platelets. The extent of anti-platelet activity of MAE was assayed in collagen-induced platelet aggregation. ATP and serotonin release was carried out. The activation of integrinαIIbβ3and phosphorylation of signaling molecules, including MAPK and Akt, were investigated with cytofluorometer and immunoblotting, respectively. The thrombus formationin vivowas also evaluated in arteriovenous shunt model of rats.Results. HPLC chromatographic analysis revealed that MAE contained rutin and isoquercetin. MAE dose-dependently inhibited collagen-induced platelet aggregation. MAE also attenuated serotonin secretion and thromboxane A2formation. In addition, the extractin vivoactivity showed that MAE at 100, 200, and 400 mg/kg significantly and dose-dependently attenuated thrombus formation in rat arterio-venous shunt model by 52.3% (P<0.001), 28.3% (P<0.01), and 19.1% (P<0.05), respectively.Conclusions. MAE inhibit platelet activation, TXB2 formation, serotonin secretion, aggregation, and thrombus formation. The plant extract could be considered as a candidate to anti-platelet and antithrombotic agent.

Sign in / Sign up

Export Citation Format

Share Document