Zinc-induced platelet aggregation is mediated by the fibrinogen receptor and is not accompanied by release or by thromboxane synthesis

We demonstrate that zinc (0.1 to 0.3 mmol/L) induces aggregation of washed platelet suspensions. Higher concentrations (1 to 3 mmol/L) of zinc were needed to aggregate platelets in platelet-rich plasma obtained from blood anticoagulated with low-molecular-weight heparin, probably due to the binding of zinc to the plasma proteins. Zinc- induced aggregation of normal washed platelets required added fibrinogen and no aggregation occurred with thrombasthenic platelets or with normal platelets pretreated with a monoclonal antibody (10E5) that blocks the platelet fibrinogen receptor. These data indicate that the platelet membrane fibrinogen receptor-glycoproteins IIb and IIIa mediate the effect of zinc. Zinc-induced aggregation was blocked by the agent TMB-8, which interferes with the internal calcium flux, and by prostacyclin, which elevates platelet cyclic adenosine monophosphate levels. Zinc-induced aggregation was not accompanied by thromboxane synthesis or by the secretion of dense-body serotonin and was not affected by preexposure of platelets to acetylsalicylic acid. Experiments with creatine phosphate/creatine phosphokinase showed that the zinc effect on platelets was independent of extracellular adenosine diphosphate (ADP). Zinc had an additive effect when platelet aggregation was stimulated with subthreshhold concentrations of collagen or ADP. Together with the known effects of nutritional zinc on in vivo bleeding, on platelet aggregation, and on lipid metabolism, the results suggest that zinc may have an important bearing on normal hemostasis, thrombosis, and atherosclerosis.

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Zinc-induced platelet aggregation is mediated by the fibrinogen receptor and is not accompanied by release or by thromboxane synthesis

Blood ◽

10.1182/blood.v66.1.213.213 ◽

1985 ◽

Vol 66 (1) ◽

pp. 213-219 ◽

Cited By ~ 29

Author(s):

P Heyns A du ◽

A Eldor ◽

R Yarom ◽

G Marx

Keyword(s):

Platelet Aggregation ◽

Dense Body ◽

Platelet Rich Plasma ◽

Adenosine Monophosphate ◽

Adenosine Diphosphate ◽

Creatine Phosphate ◽

Calcium Flux ◽

Fibrinogen Receptor ◽

Induced Aggregation

Abstract We demonstrate that zinc (0.1 to 0.3 mmol/L) induces aggregation of washed platelet suspensions. Higher concentrations (1 to 3 mmol/L) of zinc were needed to aggregate platelets in platelet-rich plasma obtained from blood anticoagulated with low-molecular-weight heparin, probably due to the binding of zinc to the plasma proteins. Zinc- induced aggregation of normal washed platelets required added fibrinogen and no aggregation occurred with thrombasthenic platelets or with normal platelets pretreated with a monoclonal antibody (10E5) that blocks the platelet fibrinogen receptor. These data indicate that the platelet membrane fibrinogen receptor-glycoproteins IIb and IIIa mediate the effect of zinc. Zinc-induced aggregation was blocked by the agent TMB-8, which interferes with the internal calcium flux, and by prostacyclin, which elevates platelet cyclic adenosine monophosphate levels. Zinc-induced aggregation was not accompanied by thromboxane synthesis or by the secretion of dense-body serotonin and was not affected by preexposure of platelets to acetylsalicylic acid. Experiments with creatine phosphate/creatine phosphokinase showed that the zinc effect on platelets was independent of extracellular adenosine diphosphate (ADP). Zinc had an additive effect when platelet aggregation was stimulated with subthreshhold concentrations of collagen or ADP. Together with the known effects of nutritional zinc on in vivo bleeding, on platelet aggregation, and on lipid metabolism, the results suggest that zinc may have an important bearing on normal hemostasis, thrombosis, and atherosclerosis.

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Inhibition of Human Platelet Aggregation by the Proteolytic Effect of Streptokinase (SK). Role of the Factor VIII Related Antigen

10.1055/s-0039-1689380 ◽

1975 ◽

Cited By ~ 1

Author(s):

R. Castillo ◽

S. Maragall ◽

J. A. Guisasola ◽

F. Casals ◽

C. Ruiz ◽

...

Keyword(s):

Platelet Aggregation ◽

Factor Viii ◽

Platelet Rich Plasma ◽

Gel Filtration ◽

Inhibitory Effect ◽

Factor Viii Related Antigen ◽

Human Factor Viii ◽

Induced Aggregation

Defective ADP-induced platelet aggregation has been observed in patients treated with streptokinase. This same effect appears “in vitro” when adding SK to platelet rich plasma (PRP). Classic hemophilia and normal platelet poor plasmas (PPP) treated with SK inhibit the aggregation of washed platelets; plasmin-treated normal human serum also shows an inhibitory effect on platelet aggregation. However, von Willebrand SK-treated plasmas do not inhibit the aggregation of washed platelets. The same results appear when plasmas are previously treated with a rabbit antibody to human factor VIII.This confirms that the antiaggregating effect is mainly linked to the digested factor VIII related antigen.The inhibition of ADP-induced platelet aggregation has been proved in gel filtration-isolated and washed platelets from SK-treated PRP.Defective ristocetin-induced platelet aggregation has also been observed- This action does not appear in washed platelets from SK-treated PRP in presence of normal PPP, but it does in presence of SK-treated PPP, which suggests that the inhibition of the ristocetin-induced aggregation is due to the lack of factor VIII and not to the factor VIII-related products.Heparin, either “in vivo” or “in vitro”, has corrected the antiaggregating effect of SK.

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Stromal cell–derived factor-1 and macrophage-derived chemokine: 2 chemokines that activate platelets

Blood ◽

10.1182/blood.v96.1.50.013k40_50_57 ◽

2000 ◽

Vol 96 (1) ◽

pp. 50-57 ◽

Cited By ~ 5

Author(s):

M. Anna Kowalska ◽

Mariusz Z. Ratajczak ◽

Marcin Majka ◽

Jianguo Jin ◽

Satya Kunapuli ◽

...

Keyword(s):

Chemokine Receptors ◽

Stromal Cell ◽

Platelet Rich Plasma ◽

Cyclic Adenosine Monophosphate ◽

Adenosine Monophosphate ◽

Creatine Phosphate ◽

Polymerase Chain ◽

Stromal Cell Derived Factor ◽

Induced Aggregation ◽

Second Wave

Platelets play roles in both thrombosis and inflammation, and chemokines that are released at sites of inflammation could potentially activate platelets. Among the chemokine receptors expressed on platelets, the CXCR4 is the receptor for chemokine stromal cell-derived factor-1 (SDF-1), and the CCR4 is the receptor for macrophage-derived chemokine (MDC). Of the chemokines tested, SDF-1 and MDC were the only 2 that activated platelets. Both are weak agonists, but they enhanced response to low-dose adenosine 5′-diphosphate (ADP), epinephrine, or serotonin. When SDF-1 and MDC were added together, full and brisk platelet aggregation occurred. Platelet activation by these 2 chemokines appears to involve distinct pathways: SDF-1 inhibited an increase in cyclic adenosine monophosphate (cAMP) following prostaglandin (PG) I2, while MDC had no effect. In contrast, MDC, but not SDF-1, lead to Ca++mobilization by platelets. Further, second-wave aggregation induced by MDC in platelet-rich plasma was inhibited by aspirin, ADP scavenger creatine phosphate/creative phosphokinase (CP/CPK), and ARL-66096, an antagonist of the ADP P2TAC receptor involved in adenylyl cyclase inhibition. But the aggregation was not affected by A3P5PS, an inhibitor of the ADP P2Y receptor. SDF-1–induced aggregation was inhibited by aspirin, but it was only slightly affected by CP/CPK, ARL-66096, or A3P5PS. Finally, the presence of chemokines in platelets was determined. Reverse transcriptase–polymerase chain reaction studies with platelet RNA did not detect the presence of SDF-1 or MDC. In summary, SDF-1 and MDC are platelet agonists that activate distinct intracellular pathways. Their importance in the development of thrombosis at sites of inflammation needs to be further evaluated.

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The pharmacology of L-670,596, a potent and selective thromboxane/prostaglandin endoperoxide receptor antagonist

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y89-155 ◽

1989 ◽

Vol 67 (9) ◽

pp. 989-993 ◽

Cited By ~ 30

Author(s):

A. W. Ford-Hutchinson ◽

Y. Girard ◽

A. Lord ◽

T. R. Jones ◽

M. Cirino ◽

...

Keyword(s):

Platelet Aggregation ◽

Guinea Pig ◽

Receptor Antagonist ◽

Competitive Inhibition ◽

Ex Vivo ◽

Platelet Rich Plasma ◽

Prostaglandin Endoperoxide ◽

Induced Aggregation

L-670,596 ((−)6,8-difluoro-9-p-methylsulfonyl benzyl-1,2,3,4-tetrahydrocarbazol-1-yl-acetic acid) has been shown to be a potent receptor antagonist as evidenced by the inhibition of the binding of 125I-labeled PTA-OH to human platelets (IC50, 5.5 × 10−9 M), inhibition of U-44069 induced aggregation of human platelet rich plasma (IC50, 1.1 × 10−7 M), and competitive inhibition of contractions of the guinea pig tracheal chain induced by U-44069 (pA2,9.0). The compound was also active in vivo as shown by inhibition of arachidonic acid and U-44069 induced bronchoconstriction in the guinea pig (ED50 values, 0.04 and 0.03 mg/kg i.v., respectively), U-44069 induced renal vasoconstriction in the pig (ED50, 0.02 mg/kg i.v.), and inhibition of ex vivo aggregation of rhesus monkey platelets to U-44069 (active 1–5 mg/kg p.o.). The selectivity of the compound was indicated by the failure to inhibit, first, ADP-induced human or primate platelet aggregation and, second, bronchoconstriction in the guinea pig in vivo and contraction of the guinea pig tracheal chain in vitro to a variety of agonists. It is concluded that L-670,596 is a potent, selective, orally active thromboxane A2/prostaglandin endoperoxide receptor antagonist.Key words: thromboxane A2, thromboxane antagonist, prostaglandin endoperoxides, platelet aggregation.

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The Effect of Cold on Platelets. II. Platelet Function After Short-term Storage at Cold Temperatures

Blood ◽

10.1182/blood.v40.5.688.688 ◽

1972 ◽

Vol 40 (5) ◽

pp. 688-696 ◽

Cited By ~ 45

Author(s):

Herman E. Kattlove ◽

Benjamin Alexander ◽

Frances White

Keyword(s):

Platelet Aggregation ◽

Room Temperature ◽

Platelet Rich Plasma ◽

Adenosine Diphosphate ◽

Serotonin Release ◽

Prolonged Storage ◽

Cold Temperatures ◽

Aggregation Of Platelets ◽

Term Storage

Abstract Citrated platelet-rich plasma (PRP) was kept at cold temperatures or room temperature. After 4 hr or more at these temperatures, the PRPs were warmed 1 hr at 37°C. This prevents the spontaneous aggregation seen in chilled PRP that is stirred immediately after warming. Platelet aggregation in response to connective tissue (CT), epinephrine, and adenosine diphosphate (ADP) was considerably greater in the PRPs originally kept at cold temperatures. In addition, chilling would restore the aggregation of platelets whose function had deteriorated due to prolonged storage at warm temperatures. Neither ADP-induced refractoriness, serotonin uptake, or CT-induced serotonin release was affected by cold. Retention in glass bead columns was greater in platelets that had been chilled than in platelets kept at room temperature or 37°C. Thus, the storage of platelets at cold temperatures leads to changes that improve platelet aggregation but may also increase platelet adhesion, which would account for the decreased in vivo survival of platelets preserved for transfusion at cold temperatures.

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In Vivo Effects of a Low Molecular Weight Heparin Fragment on Platelet Aggregation and Platelet Dependent Hemostasis in Dogs

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647036 ◽

1988 ◽

Vol 60 (02) ◽

pp. 232-235 ◽

Cited By ~ 6

Author(s):

B Ljungberg ◽

H Johnsson

Keyword(s):

Molecular Weight ◽

Platelet Aggregation ◽

Low Molecular Weight Heparin ◽

Platelet Rich Plasma ◽

Skin Flap ◽

Low Molecular Weight ◽

Dog Plasma ◽

In Vivo Effects ◽

Induced Aggregation

SummaryPlasma defibrinogenated dogs were used to study the influence of conventional heparin and a low molecular weight heparin fragment (Fragmin®, mean MW 5,000 d) on platelet dependent hemostasis. The heparins were given intravenously in gravimetri- cafly equal doses. The bleeding from standardized skin flap wounds and platelet aggregation (ADP and thrombin) was studied. In comparison, higher doses of the fragment than of heparin were required to increase the bleeding. ADP-induced aggregation in defibrinogenated platelet rich plasma (after addition of normal dog plasma) was potentiated by both heparins. After injection of heparin or the fragment, ADP induced platelet aggregation without prior addition of normal plasma to the testtube.In conclusion the heparin fragment affected bleeding to a less extent than conventional heparin. One explanation might be a weaker inhibition of thrombin-induced platelet aggregation.

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Abnormal Platelet Function in Raynaud’s Phenomenon.

10.1055/s-0039-1684618 ◽

1979 ◽

Author(s):

J. Zahavi ◽

W.A.P. Hamilton ◽

M.J.G. O’Reilly ◽

S.E. Clark ◽

L.T. Cotton ◽

...

Keyword(s):

Platelet Aggregation ◽

Healthy Subjects ◽

Platelet Rich Plasma ◽

Raynaud’S Phenomenon ◽

Adenosine Diphosphate ◽

Raynaud's Phenomenon ◽

Plasma Fibrinogen ◽

Serum Immunoglobulin ◽

Plasma Factors

Platelet aggregation (PA) induced by adenosine diphosphate (ADP) 0.6 and 4μM, 1-ephinephrine 6μM, collagen lu/ml and thrombin 0.2u/ml has been measured in citrated platelet rich plasma of 38 patients (mean age 42.2) suffering from Raynaud’s Phenomenon. In 29 of them, plasma β-thromboglobulin (βTG), measured by radioimmunoassay was determined and the results were compared to age and sex matched healthy subjects and correlated to serum immunoglobulin (Ig) and plasma fibrinogen levels. Plasma βTG (mean 72.2ng/ml, ranged 20-209) was significantly elevated in the patients compared to the controls (p ≤ 0.005). The rate and extent of platelet aggregation however, though higher in the patients than controls were significant only to ADP 0.6μM (p ≤ 0.045) rate and p ≤ 0.002 extent) and 4μM (p ≤ 0.005 rate and p ≤ 0.004 extent). Serum IgM levels were also abnormally increased in 12, IGA in one and IgG in 4 patients. There was no correlation between the platelet studies are plasma fibrinogen or serum immunoglobulin suggesting that these tests are measuring various aspects of the disease state. These results indicate that in-vivo platelet activation and “release reaction” are enhanced in patients suffering from Raynaud’s Phenomenon presumably not only by abnormal plasma factors. Furthermore, they suggest that platelets may be involved in the pathogenesis of the disease and its complications.

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Coagulation-Related Effect of Bortezomib Treatment in Patients with Relapsed or Refractory Multiple Myeloma.

Blood ◽

10.1182/blood.v110.11.2733.2733 ◽

2007 ◽

Vol 110 (11) ◽

pp. 2733-2733

Author(s):

Maurizio Zangari ◽

Jose Guerrero ◽

Federica Cavallo ◽

Michael J. Burns ◽

Keshava Prasad ◽

...

Keyword(s):

Platelet Count ◽

Platelet Aggregation ◽

Platelet Rich Plasma ◽

Factor V Leiden ◽

Coagulation Factors ◽

Factor V ◽

Post Dose ◽

Platelet Surface ◽

Induced Aggregation

Abstract Proteasomes inhibitors have been recently identified as potential agents, which can influence processes leading to thrombosis. We have previously reported a reduced incidence of deep vein thrombosis (DVT) in 69 patients enrolled in Total Therapy III and treated with (B), dexamethasone, thalidomide, cisplatin and doxorubicin with prophylactic anticoagulation. Patients with relapse MM, not previously exposed to B with normal baseline coagulation parameters (PT, PTT fibrinogen and platelet count) were eligible for the study. Except for the two PCR-based genotyping assays Factor V Leiden and Prothrombin Gene, which were assessed only at enrollment, in table one are listed coagulation factors serially assessed at baseline and within 1 hour after the first dose of B on day 1 and 4 of the first treatment cycle. Platelet Aggregation, with epinephrine, collagen, arachidonic acid, ADP and P- selectin by flow cytometry, were obtained at same time points. Results: Median values of coagulation factors pre and post B infusion are shown in table 1. Platelet count on platelet rich plasma (PRP) decreased after each B treatment (204.1±69.2 × 103 platelets/μL versus 160.8±50.3 × 103 platelets/μL). Platelet aggregation in PRP induced by 10 μM ADP was reduced by 20% and 29% in post-B on day one and four with p-values of 0.033 and 0.009 rispectively. Ristocetin induced platelet agglutination and epinephrine-induced aggregation were both negatively affected by B administration, p=0.0077 and p=0.034. Platelet aggregations elicited by collagen and arachidonic were not affected by B P-selectin expression on platelet surface was overall decrease with each agonist after B administration however no statistical differences were observed. In conclusion this pilot study has shown that even a short in vivo B exposure can significantly impaired platelet number and function and could explain clinical observations. Table 1 Test Day 1 Pre-dose Median Day 1 Post-dose Median Day 4 Pre-dose Median Day 4 Post-dose Median PT (sec) 13.4 13.85 13.55 14.4 PTT (sec) 17.35 26.2 26.95 25.5 Fibrinogen (mg/dL) 385 360 386 341.5 Protein C (70%–160%) 114 102 120 115 Protein S (65–140%) 89 85 92 92.5 Antithrombin II (190–127%) 98 97.5 100.5 102 APC Ration 2.345 2.33 2.3 2.22 T.T. (<20s) 18.2 17.9 17.7 19.45 D-Dimer (ug/mL) 0.56 0.5 0.5 0.59 Homocysteine (umol/L) 8.77 8.99 8.69 8.13

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Lu 23051, A New Potent Inhibitor Of Platelet Aggregation

10.1055/s-0038-1653265 ◽

1981 ◽

Author(s):

H D Lehmann ◽

J Gries ◽

D Lenke

Keyword(s):

Platelet Aggregation ◽

Ex Vivo ◽

Platelet Rich Plasma ◽

Coronary Vessels ◽

Inhibitory Effect ◽

Spontaneously Hypertensive ◽

Dependent Inhibition ◽

Induced Aggregation

6- [p-(2-(Chiorpropionylamino)phenyl] -4.5-dihydro-5-methyl-3(2H)-pyridazinone, LU 23051, is primarily characterized by its strong inhibition of platelet aggregation under in vitro and in vivo conditions. In vitro there is a concentration-dependent inhibition of ADP and collagen induced aggregation in platelet rich plasma of man, rat and dog. The inhibitory concentration EC 33 % is 0.0010-0.030 mg/1 (man: ADP-0.030, col 1.-0.013 mg/l) depending on species and type of aggregation. When administered orally in ex vivo experiments on rats and dogs the substance is found to have a dose-dependent antiaggregatory effect in the range from 0.1-3.16 mg/kg. The ED 33 % is 0.27-0.63 mg/kg.-In addition after oral administration the substance has a good inhibitory effect in models being based on intravascular platelet aggregation. Thus, a dose of 1 mg/kg inhibits laser-induced aggregation in mesenteric venules of rats. Mortality after i.v. injection of collagen in mice is reduced by 50 % after a dose of 0.02 mg/kg. A dose of 0.039 mg/kg prolongs the bleeding time of rats by 50 %. The aggregation-inhibiting action is of long duration (0.1 mg/kg p.o.∼24 h). The substance does not interfere with clotting.Besides its effect on platelet aggregation LU 23051 acts as vasodilatator as well. Dilatation of coronary vessels by 100 % is seen in isolated guinea-pig hearts at a concentration of 0.1 mg/l. In spontaneously hypertensive rats the substance has an anti hypertensive effect. The ED 20 % is 0.36 mg/kg p.o.The combination of antiaggregatory and vasodilatatory effects opens up interesting aspects with respect to the pharmacotherapeutic use of the new substance

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PLATELET PHAGOCYTOSIS AND AGGREGATION

The Journal of Cell Biology ◽

10.1083/jcb.27.3.531 ◽

1965 ◽

Vol 27 (3) ◽

pp. 531-543 ◽

Cited By ~ 103

Author(s):

Henry Z. Movat ◽

William J. Weiser ◽

Michael F. Glynn ◽

James F. Mustard

Keyword(s):

Platelet Aggregation ◽

Human Platelet ◽

Platelet Rich Plasma ◽

Chelating Agent ◽

Adenosine Monophosphate ◽

Adenosine Diphosphate ◽

Inhibit Platelet Aggregation ◽

Platelet Suspension ◽

Latex Particles ◽

Washed Platelet

The addition of latex particles to native (no anticoagulant) or citrated human platelet-rich plasma (PRP), or to a once-washed platelet suspension causes platelet aggregation. This aggregation is associated with phagocytosis of the latex particles by the platelets and appears to be due to release of adenosine diphosphate (ADP) from the platelets. Adenosine and adenosine monophosphate, which are known to inhibit platelet aggregation induced by ADP, also block that induced by latex. These compounds do not prevent the phagocytosis of latex particles by the platelet. The addition of iodoacetate and 2,4-dinitrophenol in appropriate concentrations to the PRP, prior to the addition of the latex, blocks platelet aggregation and phagocytosis. This is also true for the chelating agent ethylenediaminetetraacetate (EDTA). Platelets left in contact with latex for a sufficient period of time show loss of their granules. Leucocytes phagocytose both latex and platelets that had themselves phagocytosed latex. It is concluded that phagocytosis of latex particles by platelets resembles that by white cells, and that in both processes metabolic changes appear to be involved.

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