Recovery of Thromboxane A2 and Prostacyclin Production in Vivo Following Single-Dose Aspirin Treatment

1987 ◽  
pp. 427-435
Author(s):  
Rosemary Zaragoza ◽  
Guy C. Le Breton
Keyword(s):  
Single Dose ◽  
Thromboxane A2 ◽  
Dose Aspirin ◽  
Prostacyclin Production

Effect of Picotamide on Platelet Aggregation and on Thromboxane A2 Production In Vivo

1991 ◽  
Vol 65 (03) ◽  
pp. 312-316 ◽  
Author(s):  
P Minuz ◽  
C Lechi ◽  
E Arosio ◽  
P Guzzo ◽  
M Zannoni ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Single Dose ◽  
Platelet Aggregation ◽  
Urinary Excretion ◽  
Ex Vivo ◽  
Thromboxane A2 ◽  
Normal Subjects ◽  
Dose Aspirin ◽  
Induced Aggregation

SummaryEffects of picotamide (900 mg in 3 oral administrations for 7 days) on ex vivo and in vivo platelet T×A2 production and on platelet aggregation wpre evaluated in 8 patients with peripheral arteriopathy and in 8 normal subjects. Picotamide significantly reduced ADP-induced platelet aggregation, but had no effect on that induced by arachidonic acid or the thromboxane analogue U46619. Though ex vivo platelet T×A2 production (T×B2 concentration after arachidonic-acid-induced aggregation) was reduced from 946 ± 141 (mean ± SD) to 285 ± 91 ng/ml in controls and from 1515 ± 673 to 732 ± 420 ng/ml in patients with arteriopathy, there was no effect on urinary excretion of 2,3-dinor-T×B2 (in vivo indicator of platelet T×A2 production), or on in vivo PGI2 production (urinary excretion of 6-keto-PGF1α and 2,3-dinor-6-keto-PGF1α). In the same subjects, single-dose aspirin reduced ex vivo T×B2 production by at least 98% and 2,3-dinor-T×B2 excretion from 116.7 ± 61.4 to 32.6 ± 17.0 nglg creatinine in control subjects, and from 156.3 ± 66.1 to 59.1 ± 19.2 ng/g creatinine in patients with peripheral arteriopathy. Our data suggest that inhibition of platelet T×A2 production in vivo may not be picotamide’s main mechanism of action.

Aspirin Ingestion in Primary Thrombocythemia

1982 ◽  
Vol 48 (01) ◽  
pp. 072-075 ◽  
Author(s):  
Akira Hattori ◽  
Masayoshi Sanada ◽  
Reizo Nagayama ◽  
Akira Shibata ◽  
Minoru Okuma
Keyword(s):  
Single Dose ◽  
Arterial Thrombosis ◽  
Platelet Rich Plasma ◽  
Thromboxane A2 ◽  
Primary Thrombocythemia ◽  
Normal Humans ◽  
Spontaneous Platelet Aggregation ◽  
Induced Aggregation ◽  
Aspirin Ingestion

SummaryRecently Massotti et al. (14) and Patrono et al. (23) have proposed for antithrombotic therapy the use of small single dose of aspirin (ASA) every three or four days in order to inhibit thromboxane A2 production in the platelets but not to inhibit PGI2 production in the endothelium. Their data are theoretical and based on a small number of normal humans. We have examined the effect of a single ingestion of ASA (10 mg/kg) on spontaneous platelet aggregation (SPA) and collagen-induced aggregation (CA) in 11 patients with primary thrombocythemia using the original platelet-rich plasma. SPA and CA were positive in 8 out of 10 and in 11 out of 11 patients respectively before ASA ingestion. ASA abolished both types of aggregation in all patients at 12 h after the ingestion. But the recovery occurred in 1/11 in CA at 24 hr, in about half (3/8 SPA or 7/11 CA) of the patients at 48 hr, in 5/8 (SPA) and 10/11 (CA) at 72 hr and in 7/ 8 (SPA) and 11/11 (CA) at 96 hr. Since SPA and sometimes CA have been considered to be the parameters of the effect of ASA on hyperreactivity of the platelets in vivo, resulting in arterial thrombosis or insufficiency in these patients, our results suggest that daily or at least once per two days ingestion of ASA may be necessary in these patients. These results were discussed in relation to the platelet survivals (6.5–10 days) and the platelet cyclo-oxygenase or lipoxygenase activities (deficient in 3 patients for the former and in 2 for the latter) in our patients.

Thromboxane A2 Signaling Regulates Heterogeneous Platelet Activation Following Laser-Induced Injury In Mouse Cremaster Arterioles

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1055-1055
Author(s):  
Jian Shen ◽  
Fei Yang ◽  
Yujun Shen ◽  
Ying Yu ◽  
Timothy J. Stalker ◽  
...  
Keyword(s):  
Platelet Activation ◽  
Vascular Injury ◽  
Low Dose ◽  
Thromboxane A2 ◽  
Dose Aspirin ◽  
Low Dose Aspirin ◽  
Platelet Accumulation ◽  
Cox 1 ◽  
Platelet Mass

Abstract Background A recent study demonstrated that platelet accumulation following vascular injury in vivo is hierarchically organized resulting in a structure comprised of a core of fully-activated platelets that is overlaid with an unstable shell of less activated platelets (Stalker et al, Blood, 2013). This structure results from different elements of the platelet signaling network giving rise to regions that differ in platelet activation state, packing density, and stability. It was thus proposed that regional differences in platelet activation reflect regional differences in the distribution of platelet agonists. This provides new insights into heterogeneous platelet activation during platelet accumulation in vivo. Thromboxane A2 (TxA2), a dominant prostanoid product of cyclooxygenase 1 (COX-1) generated in platelets, plays an important role in the maintenance of vascular hemostasis and is a major therapeutic target of anti-platelet therapy. But its contribution to the regional architecture of a platelet mass is unknown. Approach To determine the contribution of TxA2 activity to the hierarchical organization of a thrombus, multicolor intravital microscopy was used to observe platelet accumulation and activation in thromboxane A2 receptor knockout (TP-/-) and low dose aspirin treated WT mice following laser-induced injury in mouse cremaster arterioles. Results TP-/- mice showed reduced total platelet (CD41) accumulation following vascular injury, consistent with a previous report (Yu et al, Sci Transl Med, 2012). The peak CD41 area in TP-/- mice was significantly reduced relative to WT mice (p=0.004). Interestingly, the core area of the thrombus in which the platelets are fully activated (P-selectin+), was not significantly different in TP-/- compared to WT during thrombus formation. This suggests that TxA2 signaling via the TP receptor primarily influences platelet recruitment and retention in the outer shell region of a platelet mass, but not full platelet activation in the core region. Aspirin inhibits TxA2 production through acetylation of COX-1, and is widely used as both primary and secondary prevention of cardiovascular diseases. We treated WT mice with aspirin in their drinking water (30 mg/L) for more than 1 week to mimic the effect of low dose aspirin treatment in humans (Yu et al, J Clin Invest, 2005). Similar to our findings in TP-/- mice, we found that aspirin treatment reduced total platelet accumulation following laser-induced injury in vivo (p<0.05). The decrease in peak platelet accumulation caused by aspirin was observed in the shell region at early time points (up to 2 min post-injury). In contrast to our findings in the TP-/- mice, low dose aspirin also resulted in reduced platelet activation and core region formation at later timepoints (p<0.05), suggesting that COX-1 may contribute to full platelet activation independent of TP receptor signaling. Conclusion Our studies show for the first time the role of TxA2 signaling in producing the hierarchical structure of a platelet mass formed in response to vascular injury. Our data indicate that TxA2signaling is critical for recruitment and/or retention of platelets prior to robust platelet activation including alpha granule secretion. These findings further highlight the importance of discrete spatial localization of platelet agonists within an evolving platelet plug in order to achieve the optimal hemostatic response. (This study was supported by National Natural Science Foundation of China 81170132 to Li Zhu) Disclosures: No relevant conflicts of interest to declare.

PROSTACYCLIN AND THROMBOXANE A2 GENERATION IN VIVO IN MAN -EFFECT OF LOW DOSE ASPIRIN

1987 ◽  
Author(s):  
P A Kyrle ◽  
H G Eichler ◽  
K Lechner
Keyword(s):  
Vessel Wall ◽  
Low Dose ◽  
Bleeding Time ◽  
Thromboxane A2 ◽  
Significant Inhibition ◽  
Prostaglandin Metabolism ◽  
Dose Aspirin ◽  
Low Dose Aspirin ◽  
Wall Interaction

The effect of a low-dose aspirin regimen on platelet and vascular prostaglandin metabolism was studied in vivo in man. In a double-blind placebo-controlled cross-over study, 7 healthy male volunteers were treated with aspirin (35 mg.day−1 or placebo for 7 days. After a washout period of 2 weeks, the subject were crossed to the alternate treatment. 12 hours after the last dose of aspirin or placebo formation of thromboxane A2 (TxA2) and prostacyclin (FGI2) was measured in blood emerging from a standardized injury of the microvasculature made to determine bleeding time. TxA2 and PGI2 were measured as their stable degradation products, thromboxane B2 (TxB2) and 6-keto-prostaglandin F1α (6-keto PGF1α), using radioimmunoassay procedures. When subjects were treated with placebo, there was a rapid and substantial generation of both TxA2 and PGI2 at the site of plate-let-vessel wall interaction. This was reflected by an increase of TxB2 from 2.8±1 ng/ml and of 6-keto-PGF1α from 38.6±14.6pg/ml in the first minute to 4.5±0.6 ng/ml TxB2 and 154±50 pg/ml 6-keto-PGF1α after 4 minutes. Low-dose aspirin caused a significant inhibition of both TxA2 and PGI2 generation in bleeding time blood as represented by 65-92% and 81-84% inhibition of TxB2 and 6-keto-PGF1α Respectively throughout the 4 minute study period. We conclude that (a) rapid activation of both platelet prostaglandin metabolism and vascular PGI2 biosynthesis occurs at the site of platelet-vessel wall interaction and (b) low-dose aspirin results in a significant inhibition of platelet and vascular cyclo-oxygenase activity. Thus, our data fail to confirm the concept of a differential effect of low-dose aspirin on platelet and vascular prostaglandin synthesis in vivo in man.

Effect of Single-Dose Aspirin on TXA2 and PGI2 Cyclooxygenases in vivo

1987 ◽  
Vol 17 (1-2) ◽  
pp. 40-48
Author(s):  
Rosemary Zaragoza ◽  
Guy C. Le Breton
Keyword(s):  
Single Dose ◽  
Dose Aspirin

scholarly journals Inhibition of prostacyclin and thromboxane A2 generation by low-dose aspirin at the site of plug formation in man in vivo.

Circulation ◽  
1987 ◽  
Vol 75 (5) ◽  
pp. 1025-1029 ◽  
Author(s):  
P A Kyrle ◽  
H G Eichler ◽  
U Jäger ◽  
K Lechner
Keyword(s):  
Low Dose ◽  
Thromboxane A2 ◽  
Dose Aspirin ◽  
Low Dose Aspirin ◽  
Plug Formation

Investigation of the Interaction of Blood Platelets with the Coagulation System at the Site of Plug Formation In Vivo in Man - Effect of Low-Dose Aspirin

1987 ◽  
Vol 57 (01) ◽  
pp. 062-066 ◽  
Author(s):  
P A Kyrle ◽  
J Westwick ◽  
M F Scully ◽  
V V Kakkar ◽  
G P Lewis
Keyword(s):  
Platelet Activation ◽  
Thrombin Generation ◽  
Low Dose ◽  
Bleeding Time ◽  
Blood Platelets ◽  
Dose Aspirin ◽  
Low Dose Aspirin ◽  
Plug Formation ◽  
Granule Release

SummaryIn 7 healthy volunteers, formation of thrombin (represented by fibrinopeptide A (FPA) generation, α-granule release (represented by β-thromboglobulin [βTG] release) and the generation of thromboxane B2 (TxB2) were measured in vivo in blood emerging from a template bleeding time incision. At the site of plug formation, considerable platelet activation and thrombin generation were seen within the first minute, as indicated by a 110-fold, 50-fold and 30-fold increase of FPA, TxB2 and PTG over the corresponding plasma values. After a further increase of the markers in the subsequent 3 minutes, they reached a plateau during the fourth and fifth minute. A low-dose aspirin regimen (0.42 mg.kg-1.day-1 for 7 days) caused >90% inhibition of TxB2formation in both bleeding time blood and clotted blood. At the site of plug formation, a-granule release was substantially reduced within the first three minutes and thrombin generation was similarly inhibited. We conclude that (a) marked platelet activation and considerable thrombin generation occur in the early stages.of haemostasis, (b) α-granule release in vivo is partially dependent upon cyclo-oxygenase-controlled mechanisms and (c) thrombin generation at the site of plug formation is promoted by the activation of platelets.

Increased Thromboxane Biosynthesis in Essential Thrombocythemia

1995 ◽  
Vol 74 (05) ◽  
pp. 1225-1230 ◽  
Author(s):  
Bianca Rocca ◽  
Giovanni Ciabattoni ◽  
Raffaele Tartaglione ◽  
Sergio Cortelazzo ◽  
Tiziano Barbui ◽  
...  
Keyword(s):  
Platelet Count ◽  
Platelet Activation ◽  
Essential Thrombocythemia ◽  
Therapeutic Strategy ◽  
Low Dose ◽  
Thrombotic Risk ◽  
Dose Aspirin ◽  
Gender And Age ◽  
Low Dose Aspirin

SummaryIn order to investigate the in vivo thromboxane (TX) biosynthesis in essential thromboeythemia (ET), we measured the urinary exeretion of the major enzymatic metabolites of TXB2, 11-dehydro-TXB2 and 2,3-dinor-TXB2 in 40 ET patients as well as in 26 gender- and age-matched controls. Urinary 11-dehydro-TXB2 was significantly higher (p <0.001) in thrombocythemic patients (4,063 ± 3,408 pg/mg creatinine; mean ± SD) than in controls (504 ± 267 pg/mg creatinine), with 34 patients (85%) having 11-dehydro-TXB2 >2 SD above the control mean. Patients with platelet number <1,000 × 109/1 (n = 25) had significantly higher (p <0.05) 11 -dehydro-TXB2 excretion than patients with higher platelet count (4,765 ± 3,870 pg/mg creatinine, n = 25, versus 2,279 ± 1,874 pg/mg creatinine, n = 15). Average excretion values of patients aging >55 was significantly higher than in the younger group (4,784 ± 3,948 pg/mg creatinine, n = 24, versus 2,405 ± 1,885 pg/mg creatinine, n = 16, p <0.05). Low-dose aspirin (50 mg/d for 7 days) largely suppressed 11-dehydro-TXB2 excretion in 7 thrombocythemic patients, thus suggesting that platelets were the main source of enhanced TXA2 biosynthesis. The platelet count-corrected 11-dehydro-TXB2 excretion was positively correlated with age (r = 0.325, n = 40, p <0.05) and inversely correlated with platelet count (r = -0.381, n = 40, p <0.05). In addition 11 out of 13 (85%) patients having increased count-corrected 11-dehydro-TXB2 excretion, belonged to the subgroup with age >55 and platelet count <1,000 × 1099/1. We conclude that in essential thrombocythemia: 1) enhanced 11-dehydro-TXB2 excretion largely reflects platelet activation in vivo;2) age as well as platelet count appear to influence the determinants of platelet activation in this setting, and can help in assessing the thrombotic risk and therapeutic strategy in individual patients.

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