Platelet thrombus formation by upstream activation and downstream adhesion of platelets in a microfluidic system

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.

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Morphologic Platelet Changes During Thrombus Formation in the Rat

10.1055/s-0039-1682680 ◽

1977 ◽

Author(s):

R. Wiedemann ◽

W. Weichert ◽

K. Breddin

Keyword(s):

Vessel Wall ◽

Thrombus Formation ◽

Vascular Lesions ◽

Mesenteric Vessels ◽

Platelet Thrombus ◽

Adhesion Of Platelets ◽

Damaged Vessel ◽

Morphologic Changes

The film presents observations in small mesenteric vessels (diameter 10-20 μm) of the rat using high power Nomarski optics. Under stasis conditions platelets appear as flat discs. Leucocytes are often seen creeping slowly along the intact vessel wall. Vascular lesions are produced with a focused laser beam (Hadron 513 biolaser). Immediately after the lesion platelets stick to the site of the microburn either in their native disc like shape without apparent morphologic changes or with protrusions. Within seconds these platelets swell and form protrusions. After 3-10 min, depending on the size of the lesion the vessel is occluded by a platelet thrombus. Platelets undergo further swelling. Later the thrombus is partially or completely swept away and the vessel is recanal i zed. Irreversible fusion of platelets is rarely observed. . New, usually smaller thrombi form at the damaged vessel wall. The morphologic platelet changes observed differ markedly from the changes observed during aggregation in vitro. After injection of a new antithrombotic substance (Bay G 7565) the adhesion of platelets to the damaged area is remarkably diminished. The few platelets which adhere to the site of injury show the same swelling and transformation like in untreated animals. The film demonstrates that it is possible to investigate morphologic changes of single platelets during thrombus formation. It seems possible to adapt this model for the in vivo study of antithrombotic drugs.

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Effect of chronic treatment with acetylsalicylic acid and clopidogrel on atheroprogression and atherothrombosis in ApoE-deficient mice in vivo

Thrombosis and Haemostasis ◽

10.1160/th07-03-0235 ◽

2008 ◽

Vol 99 (01) ◽

pp. 190-195 ◽

Cited By ~ 36

Author(s):

Ildiko Konrad ◽

Susanne Sauer ◽

Lena Orschiedt ◽

Maria Koellnberger ◽

Reinhard Lorenz ◽

...

Keyword(s):

Acetylsalicylic Acid ◽

Atherosclerotic Plaque ◽

Thrombus Formation ◽

Atherosclerotic Lesion ◽

Platelet Thrombus ◽

Prevention Of Atherosclerosis ◽

Adhesion Of Platelets ◽

Deficient Mice

SummaryAcetylsalicylic acid (ASA) and the thienopyridine clopidogrel are established anti-platelet drugs that significantly reduce secondary cardiovascular events in patients with manifest atherosclerosis. However, their impact on atherosclerotic lesion development remains controversial. Four-week-old ApoE-deficient mice were randomly assigned to four groups receiving a cholesterol diet together with either ASA (5 mg/kg), or clopidogrel (25 mg/kg), or a combination of both ASA and clopidogrel, or vehicle for 8–12 weeks. Using intravital microscopy we found that daily administration of ASA in combination with clopidogrel reduces platelet thrombus formation following rupture of atherosclerotic plaque in vivo by ∼50%. However, therapy with ASA or clopidogrel alone, or in combination for a period of 8–12 weeks had no significant effect on adhesion of platelets to dysfunctional endothelial cells or on atherosclerotic lesion formation in the aortic root or the carotid artery. In conclusion, anti-platelet therapy is effective in reducing platelet adhesion and subsequent thrombus formation following rupture of atherosclerotic plaque in vivo. However, our data do not support a role of either drug in the primary prevention of atherosclerosis in ApoE-deficient mice.

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Thrombus formation on artificial surfaces: Correlative microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010016176x ◽

1990 ◽

Vol 48 (3) ◽

pp. 840-841

Author(s):

Quintin J. Lai ◽

Stuart L. Cooper ◽

Ralph M. Albrecht

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Low Voltage ◽

Thrombus Formation ◽

Blood Platelets ◽

Polymer Surfaces ◽

Flow Conditions ◽

Transmission Electron ◽

Adhesion Of Platelets ◽

Microscopic Techniques

Thrombus formation and embolization are significant problems for blood-contacting biomedical devices. Two major components of thrombi are blood platelets and the plasma protein, fibrinogen. Previous studies have examined interactions of platelets with polymer surfaces, fibrinogen with platelets, and platelets in suspension with spreading platelets attached to surfaces. Correlative microscopic techniques permit light microscopic observations of labeled living platelets, under static or flow conditions, followed by the observation of identical platelets by electron microscopy. Videoenhanced, differential interference contrast (DIC) light microscopy permits high-resolution, real-time imaging of live platelets and their interactions with surfaces. Interference reflection microscopy (IRM) provides information on the focal adhesion of platelets on surfaces. High voltage, transmission electron microscopy (HVEM) allows observation of platelet cytoskeletal structure of whole mount preparations. Low-voltage, high resolution, scanning electron microscopy allows observation of fine surface detail of platelets. Colloidal gold-labeled fibrinogen, used to identify the Gp Ilb/IIIa membrane receptor for fibrinogen, can be detected in all the above microscopies.

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Physico-Chemical Explanation of Blood Cell Adhesion in Thrombus Formation

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648058 ◽

1976 ◽

Vol 36 (02) ◽

pp. 430-440 ◽

Cited By ~ 5

Author(s):

A Marmur ◽

E Ruckenstein ◽

S. R Rakower

Keyword(s):

Blood Cells ◽

Thrombus Formation ◽

Experimental Information ◽

Deposition Surface ◽

Physico Chemical ◽

Quantitative Results ◽

Energy Of Interaction ◽

Induced Aggregation ◽

Adhesion Of Platelets ◽

Hydrodynamic Factors

SummaryA model is suggested which assumes that the rate of deposition of cells is determined both by hydrodynamic factors and by Brownian motion over the potential barrier caused by London and double-layer forces in the immediate vicinity of the deposition surface. The height of the barrier in the potential energy of interaction between blood cells and various surfaces is analyzed in relation to the physical properties of the cells, surfaces, and solutions. Based on this analysis, the adhesion of platelets to injured blood vessel walls and to non-biologic materials, the lack of adhesion of red blood cells under the same conditions, the mechanism of ADP induced aggregation and the interaction with blood flow are explained. The qualitative predictions of the model are substantiated by available experimental information. Quantitative results are presented in terms of a time constant, which typifies a period of contact with a surface, during which appreciable deposition occurs.

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

Thrombosis and Haemostasis ◽

10.1055/s-0038-1655068 ◽

1967 ◽

Vol 18 (03/04) ◽

pp. 592-604 ◽

Cited By ~ 15

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.

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

Thrombosis and Haemostasis ◽

10.1055/s-0038-1666898 ◽

1979 ◽

Vol 42 (02) ◽

pp. 603-610 ◽

Cited By ~ 59

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.

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