Platelet activity and in vivo arterial thrombus formation in rats with mild hyperhomocysteinaemia

2002 ◽  
Vol 13 (8) ◽  
pp. 683-689 ◽  
Author(s):  
J Fuglsang ◽  
M Stender ◽  
J Zhou ◽  
J Møller ◽  
E Falk ◽  
...  
Keyword(s):  
Thrombus Formation ◽  
Platelet Activity ◽  
Arterial Thrombus ◽  
Mild Hyperhomocysteinaemia

scholarly journals Hirudin interruption of heparin-resistant arterial thrombus formation in baboons

Blood ◽  
1991 ◽  
Vol 77 (5) ◽  
pp. 1006-1012 ◽  
Author(s):  
AB Kelly ◽  
UM Marzec ◽  
W Krupski ◽  
A Bass ◽  
Y Cadroy ◽  
...  
Keyword(s):  
Bleeding Time ◽  
Thrombus Formation ◽  
Dependent Manner ◽  
Fibrin Deposition ◽  
Recombinant Hirudin ◽  
Arterial Thrombus ◽  
Dependent Inhibition ◽  
Antithrombotic Effects ◽  
Dose Dependent

Abstract To determine the role of thrombin in high blood flow, platelet- dependent thrombotic and hemostatic processes we measured the relative antithrombotic and antihemostatic effects in baboons of hirudin, a highly potent and specific antithrombin, and compared the effects of heparin, an antithrombin III-dependent inhibitor of thrombin. Thrombus formation was determined in vivo using three relevant models (homologous endarterectomized aorta, collagen-coated tubing, and Dacron vascular graft) by measuring: (1) platelet deposition, using gamma camera imaging of 111In-platelets; (2) fibrin deposition, as assessed by the incorporation of circulating 125I-fibrinogen; and (3) occlusion. The continuous intravenous infusion of 1, 5, and 20 nmol/kg per minute of recombinant hirudin (desulfatohirudin) maintained constant plasma levels of 0.16 +/- 0.03, 0.79 +/- 0.44, and 3.3 +/- 0.77 mumol/mL, respectively. Hirudin interrupted platelet and fibrin deposition in a dose-dependent manner that was profound at the highest dose for all three thrombogenic surfaces and significant at the lowest dose for thrombus formation on endarterectomized aorta. Thrombotic occlusion was prevented by all doses studied. In contrast, heparin did not inhibit either platelet or fibrin deposition when administered at a dose that maximally prolonged clotting times (100 U/kg) (P greater than .1), and only intermediate effects were produced at 10-fold that dose (1,000 U/kg). Moreover, heparin did not prevent occlusion of the test segments. Hirudin inhibited platelet hemostatic function in concert with its antithrombotic effects (bleeding times were prolonged by the intermediate and higher doses). By comparison, intravenous heparin failed to affect the bleeding time at the 100 U/kg dose (P greater than .5), and only minimally prolonged the bleeding time at the 1,000 U/kg dose (P less than .05). We conclude that platelet-dependent thrombotic and hemostatic processes are thrombin-mediated and that the biologic antithrombin hirudin produces a potent, dose-dependent inhibition of arterial thrombus formation that greatly exceeds the minimal antithrombotic effects produced by heparin.

Platelet Signaling in Primary Haemostasis and Arterial Thrombus Formation: Part 1

2018 ◽  
Vol 38 (04) ◽  
pp. 203-210 ◽  
Author(s):  
Rüdiger Scharf
Keyword(s):  
Platelet Activation ◽  
Thrombus Formation ◽  
Vascular Lesions ◽  
Arterial Thrombus ◽  
Platelet Signaling ◽  
Transduction Mechanisms ◽  
Granule Secretion ◽  
Von Willebrand ◽  
The Impact

AbstractPlatelets react immediately in response to traumatic vascular injury by adhesion, activation, aggregation and subsequent haemostatic plug formation. While this reaction pattern is essential for haemostasis, platelet responses can also cause occlusive thrombi in diseased arteries, leading to myocardial infarction or stroke. Initially, flowing platelets are captured from the circulation to vascular lesions. This step is mediated by glycoprotein (GP) Ib-IX-V interacting with immobilized von Willebrand factor (VWF) on exposed subendothelial components. Tethered platelets can now bind to collagen through GPVI and integrin α2β1. Outside-in signals from the adhesion receptors act synergistically with inside-out signals from soluble stimuli and induce platelet activation. These mediators operate through G protein–coupled receptors and reinforce adhesion and activation. Typical manifestations of activated platelets include calcium mobilization, procoagulant activity, cytoskeletal reorganization, granule secretion and aggregation. This requires activation of integrin αIIbβ3 with shifting into a high-affinity state and is indispensable to bind soluble fibrinogen, VWF and fibronectin. The multiple interactions and the impact of thrombin result in firm adhesion and recruitment of circulating platelets into growing aggregates. A fibrin meshwork supports stabilization of haemostatic thrombi and prevents detachment by the flowing blood. This two-part review provides an overview of platelet activation and signal transduction mechanisms with a focus on αIIbβ3-mediated outside-in signaling in integrin variants. In the first part, a three-stage model of platelet recruitment and activation in vivo is presented. Along with that, platelet responses upon exposure to thrombogenic surfaces followed by platelet-to-platelet interactions and formation of haemostatic thrombi are discussed. Moreover, several determinants involved in pathological thrombosis will be reviewed.

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.

A Humanin Analog Attenuates Platelet Responses to Vascular Injury

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1131-1131 ◽  
Author(s):  
Lijie Ren ◽  
Qiang Li ◽  
Zhao Zeng ◽  
Peipei Mou ◽  
Xiaohui Liu ◽  
...  
Keyword(s):  
Amino Acid ◽  
Platelet Activation ◽  
Thrombus Formation ◽  
Ischemia Reperfusion ◽  
Treated Group ◽  
Human Platelets ◽  
Control Group ◽  
Arterial Thrombus ◽  
Group 3

Abstract Abstract 1131 Humanin (HN), a 24-amino acid endogenous antiapoptotic peptide, was initially shown to protect against neuronal cell death by Alzheimer's disease-related insults. It has recently been found that an exogenous analog of HN (HNG) in which the 14th amino acid serine is replaced with glycine protected against cerebral and cardiac ischemia reperfusion (I/R) injury in cortical neurons and cardiomyocytes, respectively. Platelet activation and thrombus formation has been shown to play an important role during I/R injury by exacerbating the extent of the infarct size. However, it is presently unknown whether HNG affects platelet function and the subsequent arterial thrombus formation. We thus examined whether HNG affects platelet activation and thrombus formation both in vitro and in vivo. Human platelets were isolated from healthy adults. Preincubation of washed human platelets with HNG (4μM) reduced collagen- or convulxin-induced platelet aggregation by 56.8% (P<0.05) and 71.9% (P<0.001), respectively. Similarly, HNG significantly reduced ATP release stimulated by collagen or convulxin. Convulxin-induced P-selectin expression and fibrinogen binding on single platelet was inhibited by HNG, as measured by flow cytometry. Moreover, HNG reduced platelet spreading on the fibrinogen coated surface by 62.9 % (P <0.05). Western blot revealed a reduction of platelet AKT phosphorylation by HNG upon collagen stimulation, implying the involvement of PI3K pathway. In addition, MAPK P38 phosphorylation by collagen and convulxin was also reduced by HNG. HNG effects on thrombus formation were tested in vivo in a ferric chloride-induced carotid artery injury model in mice. The intraperitoneal injection of HNG (25μg/kg) to male C57BL6/J mice significantly extended the first occlusion time (7.3±0.4 min, N=10), when compared to the saline injected littermates (5.4±0.7 min, N=12) (P <0.05). Furthermore, the number of mice that formed stable thrombus was less in the HNG–treated group (3/13) than the control group (6/13), while the non-occlusion mouse number was more in the HNG-treated group (3/13) than the control group (1/13). Together, these data show that HNG inhibits platelet activation and arterial thrombus formation. This might suggest that the protective effects of HNG against ischemia reperfusion injury could be, in part, via attenuating platelet activation. Therefore, HNG could be a potential therapeutic agent in thrombotic and cardiovascular disorders. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Bruton tyrosine kinase is essential for botrocetin/VWF-induced signaling and GPIb-dependent thrombus formation in vivo

Blood ◽  
2006 ◽  
Vol 108 (8) ◽  
pp. 2596-2603 ◽  
Author(s):  
Junling Liu ◽  
Malinda E. Fitzgerald ◽  
Michael C. Berndt ◽  
Carl W. Jackson ◽  
T. Kent Gartner
Keyword(s):  
Tyrosine Kinase ◽  
Thrombus Formation ◽  
Dependent Manner ◽  
Akt Phosphorylation ◽  
Atp Secretion ◽  
Arterial Thrombus ◽  
Bruton Tyrosine Kinase ◽  
Von Willebrand ◽  
Willebrand Factor

AbstractBotrocetin (bt)-facilitated binding of von Willebrand factor (VWF) to the platelet membrane glycoprotein (GP) Ib-IX-V complex on platelets in suspension initiates a signaling cascade that causes αIIbβ3 activation and platelet aggregation. Previous work has demonstrated that bt/VWF-mediated agglutination activates αIIbβ3 and elicits ATP secretion in a thromboxane A2 (TxA2)-dependent manner. The signaling that results in TxA2 production was shown to be initiated by Lyn, enhanced by Src, and propagated through Syk, SLP-76, PI3K, PLCγ2, and PKC. Here, we demonstrate that the signaling elicited by GPIb-mediated agglutination that results in TxA2 production is dependent on Bruton tyrosine kinase (Btk). The results demonstrate that Btk is downstream of Lyn, Syk, SLP-76, and PI3K; upstream of ERK1/2, PLCγ2, and PKC; and greatly enhances Akt phosphorylation. The relationship(s), if any, between ERK1/2, PLCγ2, and PKC were not elucidated. The requirement for Btk and TxA2 receptor function in GPIb-dependent arterial thrombosis was confirmed in vivo by characterizing blood flow in ferric chloride-treated mouse carotid arteries. These results demonstrate that the Btk family kinase, Tec, cannot provide the function(s) missing because of the absence of Btk and that Btk is essential for both bt/VWF-mediated agglutination-induced TxA2 production and GPIb-dependent stable arterial thrombus formation in vivo.

CLEC-2 is an essential platelet-activating receptor in hemostasis and thrombosis

Blood ◽  
2009 ◽  
Vol 114 (16) ◽  
pp. 3464-3472 ◽  
Author(s):  
Frauke May ◽  
Ina Hagedorn ◽  
Irina Pleines ◽  
Markus Bender ◽  
Timo Vögtle ◽  
...  
Keyword(s):  
Platelet Activation ◽  
Thrombus Formation ◽  
Antibody Treatment ◽  
Cellular Activation ◽  
Primary Hemostasis ◽  
Arterial Thrombus ◽  
Normal Adhesion

Abstract Damage to the integrity of the vessel wall leads to exposure of the subendothelial extracellular matrix (ECM), triggering platelet activation and aggregation. This process is essential for primary hemostasis but it may also lead to arterial thrombosis. Although the mechanisms underlying platelet activation on the ECM are well explored, it is less clear which receptors mediate cellular activation in a growing thrombus. Here we studied the role of the recently identified C-type lectin-like receptor 2 (CLEC-2) in this process. We show that anti–CLEC-2 antibody treatment of mice leads to complete and highly specific loss of CLEC-2 in circulating platelets for several days. CLEC-2–deficient platelets displayed normal adhesion under flow, but subsequent aggregate formation was severely defective in vitro and in vivo. As a consequence, CLEC-2 deficiency was associated with increased bleeding times and profound protection from occlusive arterial thrombus formation. These results reveal an essential function of CLEC-2 in hemostasis and thrombosis.

The Role of Platelet Adhesion Receptor GPIb α Far Exceeds That of Its Main Ligand von Willebrand Factor in Arterial Thrombosis.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1797-1797 ◽  
Author(s):  
Wolfgang Bergmeier ◽  
Crystal L. Piffath ◽  
Tobias Goerge ◽  
Stephen M. Cifuni ◽  
Zaverio M. Ruggeri ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Arterial Thrombosis ◽  
Platelet Adhesion ◽  
Thrombus Formation ◽  
Interleukin 4 ◽  
Arterial Thrombus ◽  
A Site ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract GPIbα binding to von Willebrand factor (VWF) exposed at a site of vascular injury is thought to be the first step in the formation of a hemostatic plug. However, our previous studies in VWF-deficient mice demonstrated delayed but not absent arterial thrombus formation suggesting that, under these conditions, GPIbα may bind other ligands or that a receptor other than GPIbα can mediate platelet adhesion. Here we studied thrombus formation in transgenic mice expressing GPIbα in which the extracellular domain was replaced by that of the human interleukin-4 receptor (IL4Rα/GPIbα-tg mice). Platelet adhesion to ferric chloride-treated mesenteric arterioles in IL4Rα/GPIbα-tg mice was virtually absent in contrast to avid adhesion in wild-type (WT) mice. As a consequence, arterial thrombus formation was completely inhibited in the mutant mice. Our studies further show that, when infused into WT recipient mice, IL4Rα/GPIbα-tg platelets or WT platelets lacking the 45 kD N-terminal domain of GPIbα failed to incorporate into growing arterial thrombi, even if the platelets were activated prior to infusion. Surprisingly, platelets lacking β3 integrins, which are unable to form thrombi on their own, incorporated efficiently into WT thrombi. Our studies provide in vivo evidence that GPIbα is absolutely required for recruitment of platelets to both exposed subendothelium and thrombi under arterial flow conditions. Thus, GPIbα contributes to arterial thrombosis by important adhesion mechanisms independent of the binding to VWF.

scholarly journals An Antithrombotic Strategy by Targeting Phospholipase D in Human Platelets

2018 ◽  
Vol 7 (11) ◽  
pp. 440 ◽  
Author(s):  
Wan Lu ◽  
Chi Chung ◽  
Ray Chen ◽  
Li Huang ◽  
Li Lien ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Platelet Activation ◽  
Phospholipase D ◽  
Thrombus Formation ◽  
Human Platelets ◽  
Platelet Activity ◽  
Clot Retraction ◽  
First Time

Phospholipase D (PLD) is involved in many biological processes. PLD1 plays a crucial role in regulating the platelet activity of mice; however, the role of PLD in the platelet activation of humans remains unclear. Therefore, we investigated whether PLD is involved in the platelet activation of humans. Our data revealed that inhibition of PLD1 or PLD2 using pharmacological inhibitors effectively inhibits platelet aggregation in humans. However, previous studies have showed that PLD1 or PLD2 deletion did not affect mouse platelet aggregation in vitro, whereas only PLD1 deletion inhibited thrombus formation in vivo. Intriguingly, our data also showed that the pharmacological inhibition of PLD1 or PLD2 does not affect mouse platelet aggregation in vitro, whereas the inhibition of only PLD1 delayed thrombus formation in vivo. These findings indicate that PLD may play differential roles in humans and mice. In humans, PLD inhibition attenuates platelet activation, adhesion, spreading, and clot retraction. For the first time, we demonstrated that PLD1 and PLD2 are essential for platelet activation in humans, and PLD plays different roles in platelet function in humans and mice. Our findings also indicate that targeting PLD may provide a safe and alternative therapeutic approach for preventing thromboembolic disorders.

Discrimination Between Prostglandin-Dependent And-Independent Functions Of Essential Fatty Acids In Arterial Throm- Bogenesis

1981 ◽  
Author(s):  
U M T Houtsmuller ◽  
G Hornstra ◽  
E Haddeman
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Linoleic Acid ◽  
Platelet Aggregation ◽  
Arterial Thrombosis ◽  
Thrombus Formation ◽  
Arterial Thrombus ◽  
Induced Aggregation

Arterial thrombus formation is reduced in essential fatty acid (EFA) deficiency. This goes together with an enhanced thrombin induced aggregation of platelets in vitro,whereas collagen-induced aggregation is definitely suppressed. A small amount of linoleic acid (18:2 (n-6)) is able to cure EFA-deficiency and to normalize arterial thrombogenesis. This latter effect may be due to either the structural function of this EFA or to its function as the ultimate dietary precursor of prostaglandins (PG). Columbinic acid, a stereo-isomer of γ-linolenic acid (18:3 (n-6)) was recently shown to possess all the structural functions of EFA, but not the PG-dependent ones. This fatty acid therefore presents a suitable tool to investigate the PG-dependence of arterial thrombogenesis and its underlying processes. We therefore compared the effect of small amounts of linoleic and columbinic acid (both as methylesters) on the water vapour release in vivo (which is a sensitive parameter for a non-PG dependent function of polyenoic fatty acids), arterial thrombosis tendency (time needed for the thrombotic obstruction of an aorta prosthesis) and platelet aggregation in vitro (aggregometry) induced by collagen and thrombin. In contrast to linoleic acid, columbinic acid did not normalize arterial thrombosis tendency and collagen induced platelet aggregation. Columbinic acid was equally effective as linoleic acid in the normalization of the water vapour release in vivo and of the thrombin-induced aggregation. We conclude that arterial thrombus formation and collagen- induced aggregation greatly depend on prostanoid formation, whereas thrombin-induced aggregation does not. The structural role of polyenoic fatty acids in thrombin-induced aggregation may provide a tool in the elucidation of factors determining the thrombin-sensitivity of blood platelets.

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