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Title: Effects of heparin on platelet aggregation and release and thromboxane A2 production

Abstract

Heparin, when added to citrated platelet-rich plasma (PRP), caused potentiation of platelet aggregation and the release reaction induced by the aggregating agents adenosine diphosphate (ADP), arachidonic acid, collagen, and epinephrine. At low concentrations (4.7 x 10(-5) M) arachidonic acid failed to cause aggregation of platelets in citrated PRP. However, in the presence of heparin, the same concentration of arachidonic acid caused aggregation. Examination of PRP for the presence of thromboxane A2 (TxA2) by use of a bioassay revealed that heparin also stimulated release of TxA2. This finding indicated that platelets released more TxA2 when they were challenged by low concentrations of arachidonic acid in the presence of heparin than in its absence. Platelets were labeled with /sup 3/H-arachidonic acid and /sup 14/C-serotonin, and attempts were made to determine whether heparin stimulated the platelet release reaction first with subsequent increased production of TxA2, or alternatively, whether heparin stimulated TxA2 production first with subsequent enhancement of the release reaction. In view of the demonstrated simultaneous release of /sup 14/C-serotonin and /sup 3/H-arachidonic acid metabolites, it appeared that either release of /sup 14/C and /sup 3/H occurs concurrently or, even if one of these events is dependent on the other, both events takemore » place in rapid succession. Timed sequential studies revealed that in the presence of arachidonic acid, the addition of heparin hastened the apparently simultaneous release of both /sup 14/C and /sup 3/H.« less

Authors:
; ; ; ;
Publication Date:
OSTI Identifier:
5589402
Resource Type:
Journal Article
Resource Relation:
Journal Name: Am. J. Pathol.; (United States); Journal Volume: 104:2
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; CARBON 14 COMPOUNDS; ISOTOPE APPLICATIONS; HEPARIN; BIOLOGICAL EFFECTS; TRITIUM COMPOUNDS; ADP; ADRENALINE; ARACHIDONIC ACID; BLOOD PLASMA; BLOOD PLATELETS; COLLAGEN; METABOLITES; QUANTITATIVE CHEMICAL ANALYSIS; QUANTITY RATIO; RADIOIMMUNOASSAY; ADRENAL HORMONES; AMINES; ANTICOAGULANTS; AUTONOMIC NERVOUS SYSTEM AGENTS; BIOLOGICAL MATERIALS; BLOOD; BLOOD CELLS; BODY FLUIDS; CARBOHYDRATES; CARBOXYLIC ACIDS; CARDIOTONICS; CARDIOVASCULAR AGENTS; CHEMICAL ANALYSIS; DRUGS; HEMATOLOGIC AGENTS; HORMONES; LABELLED COMPOUNDS; MATERIALS; MONOCARBOXYLIC ACIDS; MUCOPOLYSACCHARIDES; NEUROREGULATORS; NUCLEOTIDES; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC SULFUR COMPOUNDS; POLYSACCHARIDES; PROTEINS; RADIOASSAY; SACCHARIDES; SCLEROPROTEINS; STEROID HORMONES; SYMPATHOMIMETICS; TRACER TECHNIQUES; 550201* - Biochemistry- Tracer Techniques; 550501 - Metabolism- Tracer Techniques

Citation Formats

Mohammad, S.F., Anderson, W.H., Smith, J.B., Chuang, H.Y., and Mason, R.G.. Effects of heparin on platelet aggregation and release and thromboxane A2 production. United States: N. p., 1981. Web.
Mohammad, S.F., Anderson, W.H., Smith, J.B., Chuang, H.Y., & Mason, R.G.. Effects of heparin on platelet aggregation and release and thromboxane A2 production. United States.
Mohammad, S.F., Anderson, W.H., Smith, J.B., Chuang, H.Y., and Mason, R.G.. 1981. "Effects of heparin on platelet aggregation and release and thromboxane A2 production". United States. doi:.
@article{osti_5589402,
title = {Effects of heparin on platelet aggregation and release and thromboxane A2 production},
author = {Mohammad, S.F. and Anderson, W.H. and Smith, J.B. and Chuang, H.Y. and Mason, R.G.},
abstractNote = {Heparin, when added to citrated platelet-rich plasma (PRP), caused potentiation of platelet aggregation and the release reaction induced by the aggregating agents adenosine diphosphate (ADP), arachidonic acid, collagen, and epinephrine. At low concentrations (4.7 x 10(-5) M) arachidonic acid failed to cause aggregation of platelets in citrated PRP. However, in the presence of heparin, the same concentration of arachidonic acid caused aggregation. Examination of PRP for the presence of thromboxane A2 (TxA2) by use of a bioassay revealed that heparin also stimulated release of TxA2. This finding indicated that platelets released more TxA2 when they were challenged by low concentrations of arachidonic acid in the presence of heparin than in its absence. Platelets were labeled with /sup 3/H-arachidonic acid and /sup 14/C-serotonin, and attempts were made to determine whether heparin stimulated the platelet release reaction first with subsequent increased production of TxA2, or alternatively, whether heparin stimulated TxA2 production first with subsequent enhancement of the release reaction. In view of the demonstrated simultaneous release of /sup 14/C-serotonin and /sup 3/H-arachidonic acid metabolites, it appeared that either release of /sup 14/C and /sup 3/H occurs concurrently or, even if one of these events is dependent on the other, both events take place in rapid succession. Timed sequential studies revealed that in the presence of arachidonic acid, the addition of heparin hastened the apparently simultaneous release of both /sup 14/C and /sup 3/H.},
doi = {},
journal = {Am. J. Pathol.; (United States)},
number = ,
volume = 104:2,
place = {United States},
year = 1981,
month = 8
}
  • Fibronectin and heparin binding growth factor-type 1 have been affixed to vascular graft surfaces to enhance the attachment and the proliferation of transplanted endothelial cells, respectively. The current study examines the effect of fibronectin and heparin binding growth factor-type 1 on platelet adhesion and activation in vivo and on platelet aggregation in vitro. Expanded polytetrafluoroethylene prostheses (5 cm x 4 mm internal diameter) were treated either with fibronectin (n = 9), fibronectin/heparin/heparin binding growth factor-type 1/heparin (n = 12), or neither (n = 13) and were interposed into canine aortoiliac systems bilaterally. Autogenous radiolabeled (Indium 111 oxine, 650 microCi) plateletsmore » were injected intravenously before reestablishment of circulation. Perfusion was maintained for 30 minutes, and prostheses were removed with segments of native aorta and distal iliac arteries bilaterally. Specimens were examined for thrombus-free surface area, by gamma well counting for adherent radiolabeled platelets, and by light microscopy and transmission and scanning electron microscopic techniques. Results showed that both the fibronectin and fibronectin/heparin/heparin binding growth factor-type 1/heparin pretreated prostheses contained significantly greater numbers of platelets and adherent radioactivity than did control graft segments when normalized to their ipsilateral iliac arteries. Fibronectin/heparin/heparin binding growth factor-type 1/heparin pretreated prostheses contained 27 +/- 16 times more radioactivity per square millimeter than ipsilateral iliac arteries, fibronectin pretreated prostheses had 13 +/- 8 times more radioactivity per square millimeter than ipsilateral iliac arteries, and untreated expanded polytetrafluoroethylene had 4 +/- 3 times more radioactivity per square millimeter than ipsilateral iliac arteries.« less
  • We report a case of the heparin-induced thrombocytopenia and thrombosis syndrome presenting with acute ischemia of a lower limb. The patient was successfully treated by withdrawal of heparin products, intraarterial urokinase, and platelet anti-aggregation therapy consisting of Dextran and aspirin.
  • Highlights: • We investigated the impact of cyclic nucleotide analogues on platelet activation. • Different time dependence were found for inhibition of platelet activation. • Additive effect was found using PKA- and PKG-activating analogues. • Our results may explain some of the discrepancies reported for cNMP signalling. - Abstract: In platelets, nitric oxide (NO) activates cGMP/PKG signalling, whereas prostaglandins and adenosine signal through cAMP/PKA. Cyclic nucleotide signalling has been considered to play an inhibitory role in platelets. However, an early stimulatory effect of NO and cGMP-PKG signalling in low dose agonist-induced platelet activation have recently been suggested. Here, we investigatedmore » whether different experimental conditions could explain some of the discrepancy reported for platelet cGMP-PKG-signalling. We treated gel-filtered human platelets with cGMP and cAMP analogues, and used flow cytometric assays to detect low dose thrombin-induced formation of small platelet aggregates, single platelet disappearance (SPD), platelet-derived microparticles (PMP) and thrombin receptor agonist peptide (TRAP)-induced P-selectin expression. All four agonist-induced platelet activation phases were blocked when platelets were costimulated with the PKG activators 8-Br-PET-cGMP or 8-pCPT-cGMP and low-doses of thrombin or TRAP. However, extended incubation with 8-Br-PET-cGMP decreased its inhibition of TRAP-induced P-selectin expression in a time-dependent manner. This effect did not involve desensitisation of PKG or PKA activity, measured as site-specific VASP phosphorylation. Moreover, PKG activators in combination with the PKA activator Sp-5,6-DCL-cBIMPS revealed additive inhibitory effect on TRAP-induced P-selectin expression. Taken together, we found no evidence for a stimulatory role of cGMP/PKG in platelets activation and conclude rather that cGMP/PKG signalling has an important inhibitory function in human platelet activation.« less
  • The present study investigated the role of cAMP-dependent protein kinase in modulating calcium fluxes in platelet-derived membrane vesicles enriched in the dense tubular system. Incubation of vesicles (22/sup 0/C) with 50 ..mu..M CaCl/sub 2/, 5mM phosphate and 4.5 mM ATP resulted in the accumulation of greater than 100 nmole calcium/mg protein at steady-state. If the vesicles were pretreated with protein kinase inhibitor (0.5-4.0 mg/ml) there was a marked, dose-dependent reduction in calcium uptake activity. Furthermore, addition of protein kinase inhibitor (2-12 mg/ml) at steady-state was found to cause a rapid, dose-dependent release of vesicle-accumulated calcium. Although neither peak I normore » peak II cAMP-dependent protein kinase-augmented calcium accumulation during equilibration with /sup 45/Ca, incubation of vesicles with protein kinase did substantially inhibit TXA/sub 2/-induced calcium release. The ability of protein kinase inhibitor to block calcium accumulation and cause calcium release supports the notion that protein kinase plays an essential role in the calcium sequestering capacity of platelet membrane vesicles. Furthermore, the finding that protein kinase inhibits TXA/sub 2/-induced calcium release suggests that TXA/sub 2/ may act by modulation of protein kinase activity.« less
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