beraprost and Thrombosis

To assess the time to first on-study vascular thromboembolic events (VTEs) of clopidogrel (CL) or beraprost sodium (BPS) in Chinese population with end-stage renal disease (ESRD) treated with arteriovenous fistula (AVF) surgery.. From Jan 2009 to May 2015, 346 ESRD cases suffering an AVF surgery and undergoing oral administration of 75 mg CL (initial dose of 300 mg), 1 time/day, for 4 weeks or 40 μg BPS, 3 times/day, for 4 weeks were retrospectively assessed. The primary outcome was time to first on-study VTE.. In total, 222 ESRD cases (CL, n = 112; BPS, n = 110) were assessed, with a median follow-up time of 38.1 months (range, 37-40 months). The mean time to first on-study VTE was 1.2 weeks (0.5-2.3) and 1.8 weeks (1.2-3.8) for CL and BPS, respectively (HR 0.27, 95% CI 0.16-1.45; P = 0.00). An increased incidence of VTEs was found during the 1th-month follow-up, with rates of 14.2 and 5.5% for CL and BPS, respectively (P = 0.03). The difference persisted over time, with rates of 24.1 and 11.8% at final follow-up, respectively (P = 0.02).. CL with an increased risk of VTEs tended to have a VTE within the 1st month after cessation compared with BPS.

Topics: Adult; Aged; Arteriovenous Shunt, Surgical; China; Clopidogrel; Constriction, Pathologic; Epoprostenol; Female; Hemorrhage; Humans; Incidence; Kidney Failure, Chronic; Male; Middle Aged; Platelet Aggregation Inhibitors; Renal Dialysis; Retrospective Studies; Thrombosis; Time Factors; Young Adult

As the pathogenesis of arterial thrombosis often includes platelet thrombus formation (PTF), antiplatelet agents are commonly used for the prevention of thromboembolic events. Here, using a novel microchip flow-chamber system we developed to quantitatively analyze the PTF process, we evaluated the pharmacological efficacies of antiplatelet agents under different arterial shear rates. Hirudin-anticoagulated whole blood was perfused over a collagen-coated microchip at shear rates of 1000, 1500, and 2000s(-1), and PTF in the absence and presence of various antiplatelet agents was observed microscopically and quantified by measuring flow-pressure changes. The onset of PTF was measured as T(10) (time to reach 10 kPa), and AUC(10) (area under the flow pressure curve for the first 10 min) was calculated to quantify the overall stability of the formed thrombus. Aspirin and AR-C66096 (P2Y(12)-antagonist) at high concentrations (50 μM and 1000 nM, respectively) prolonged T(10) only modestly (AR-C66096>aspirin), but effectively decreased AUC(10), resulting in unstable PTF at all examined shear rates. With dual inhibition using both aspirin (25 μM) and ARC-66096 (250 nM), AUC(10) was drastically reduced. Nearly complete suppression of AUC(10) was also observed with abciximab (2 μg ml(-1)) and beraprost (PGI(2)-analog; 4 nM). Although OS-1 (GPIbα-antagonist; 100 nM) prevented complete capillary occlusion, significant amounts of microscopic thrombi were observed on the collagen surface. In contrast to abciximab and beraprost, OS-1 differentially affected PTF under higher shear conditions. Our novel analytical system is capable of distinguishing the pharmacological effects of various antiplatelet agents under physiological shear rates, suggesting that this system may aid in the determination of the appropriate type and dose of antiplatelet agent in the clinical setting.

Topics: Abciximab; Adenosine Triphosphate; Adult; Antibodies, Monoclonal; Area Under Curve; Aspirin; Blood Platelets; Blood Pressure; Collagen; Dose-Response Relationship, Drug; Epoprostenol; Equipment Design; Female; Humans; Immunoglobulin Fab Fragments; Lab-On-A-Chip Devices; Male; Microscopy, Video; Middle Aged; Platelet Aggregation; Platelet Aggregation Inhibitors; Platelet Function Tests; Predictive Value of Tests; Regional Blood Flow; Stress, Mechanical; Thrombosis; Time Factors

TRA-418, a compound with both thromboxane A2 receptor (TP receptor) antagonistic and prostacyclin receptor (IP receptor) agonistic activities, was synthesised in our laboratory as a new antithrombotic agent. In this study, we examined the effects of TRA-418 on platelet-leukocyte interactions in human whole blood. Platelet-leukocyte interactions were induced by U-46619 in the presence of epinephrine (U-46619 + epinephrine) or with thrombin receptor agonist peptide 1-6 (TRAP). Platelet-leukocyte interactions were assessed by flow cytometry, with examination of both platelet-neutrophil and platelet-monocyte complexes. In a control experiment, the TP receptor antagonist SQ-29548 significantly inhibited the induction of platelet-leukocyte complexes by the combination of U-46619 and epinephrine, but not TRAP-induced formation of platelet-leukocyte complexes. Conversely, the IP receptor agonist beraprost sodium inhibited platelet-leukocyte complex formation induced by both methods, although the IC50 values of beraprost sodium for U-46619 + epinephrine were at least 10-fold greater than for TRAP. Under such conditions, TRA-418 inhibited both U-46619 + epinephrine-induced and TRAP-induced platelet-leukocyte complex formation in a concentration-dependent manner, in a similar range. These results suggest that TRA-418 exerts its inhibitory effects on platelet-leukocyte interactions by acting as a TP receptor antagonist as well as an IP receptor agonist in an additive or synergistic manner. These inhibitory effects of TRA-418 on formation of platelet-leukocyte complexes suggest the compound is beneficial effects as an antithrombotic agent.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Blood Platelets; Bridged Bicyclo Compounds, Heterocyclic; Cell Communication; Cell Separation; Cells, Cultured; Epinephrine; Epoprostenol; Fatty Acids, Unsaturated; Flow Cytometry; Humans; Hydrazines; Leukocytes; Oxazines; Peptide Fragments; Platelet Activation; Receptors, Epoprostenol; Receptors, Thromboxane A2, Prostaglandin H2; Thrombosis

The pathogenesis of intestinal damage caused by bolus intravenous injection of endotoxin (ETX; 3 mg/kg) was investigated. Administration of ETX to rats induced reddish discoloration suggestive of bleeding, increased hemoglobin amounts, and leakage of plasma protein in the intestine. However, light microscopic examination of the intestine demonstrated blood congestion of the microvessels. Plasma accumulation was partially inhibited by combined pretreatment with a histamine H1 antagonist and a serotonin (5-HT) antagonist. Neither a 5-lipoxygenase inhibitor, a soybean trypsin inhibitor, nor atropine was observed to inhibit plasma accumulation. Both the intestinal leakage of plasma and the accumulation of hemoglobin were completely inhibited by indomethacin, a selective thromboxane A synthetase inhibitor (OKY 1581), and a stable PGI2 analogue (beraprost). Intravital microscopic observation of the microvessels of the small intestinal villi demonstrated microthrombus formation within several minutes after the injection of ETX, and pretreatment with OKY 1581 attenuated the formation of microthrombus. Platelet counts decreased significantly 10 min after ETX administration, and the decrease was not inhibited by pretreatment with either OKY 1581 or beraprost. Prothrombin time (PT) and activated partial thromboplastin time (APTT) were not prolonged. These observations thus suggest that microcirculatory disturbances by platelet thrombus, which are mediated by thromboxane A2 at least in part, play an important role in ETX-induced intestinal damage.

Topics: Animals; Capillary Leak Syndrome; Cyclooxygenase Inhibitors; Endotoxins; Enzyme Inhibitors; Epoprostenol; Escherichia coli; Gastrointestinal Hemorrhage; Indomethacin; Intestine, Small; Male; Methacrylates; Microcirculation; Platelet Activation; Rats; Rats, Sprague-Dawley; Shock, Septic; Specific Pathogen-Free Organisms; Thrombosis; Thromboxane A2; Thromboxane-A Synthase

The anti-platelet effects of FK409 ((+/-)-(E)-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexeneamide) , a new spontaneous nitric oxide releaser, and TRK-100 (sodium dl-4-[(1R,2R,3aS,8bS)-1,2,3a,8b-tetra-hydro-2-hydroxy-1-[(3S ,4RS)-3-hydroxy- 4-methyl-oct-6-yen-(E)-1-enyl]-5-cyclopenta[b]benzofuranyl]butyrate), a stable prostacyclin analogue, were studied both in vivo and in vitro. FK409 and TRK-100 inhibited ADP-induced platelet aggregation in rat platelet-rich plasma at 1.0 and 0.032 microM, respectively. In a rat extracorporeal shunt model, FK409 suppressed thrombus formation dose dependently and significantly at 1.0 mg/kg and showed the maximum inhibition (52% inhibition) at 10 mg/kg. TRK-100 showed 79% inhibition of thrombus formation at 1.0 mg/kg, but not at less than 1.0 mg/kg. At the doses required for antiplatelet effects, TRK-100 decreased mean blood pressure significantly but FK409 did not alter the blood pressure. These data suggest that FK409 shows more selective activities on platelets than TRK-100 in these experiments.

Topics: Adenosine Diphosphate; Administration, Oral; Analysis of Variance; Animals; Blood Platelets; Blood Pressure; Blood Pressure Determination; Dose-Response Relationship, Drug; Epoprostenol; Male; Nitro Compounds; Platelet Aggregation Inhibitors; Rats; Rats, Sprague-Dawley; Thrombosis

Patients with carotid atheromatous lesions were prospectively studied with indium-111 platelet imaging, platelet aggregability and B-mode real-time ultrasound tests to determine the short-term effects of orally active prostacyclin analogue TRK-100 (40 micrograms, three times daily for 4 weeks). To establish baseline values, all patients underwent indium-111 platelet imaging, platelet aggregation study and B-mode ultrasound. The results were positive for carotid plaque and platelet accumulation. Visual analysis showed repeated platelet scintigrams to be unchanged in five patients without antithrombotic therapy; repeated ultrasound studies showed no change in eight of ten plaques, while one showed progression and one regression of the plaque. In five TRK-100 treated patients, five of seven lesions with platelet accumulation at the baseline became negative, and two remained unchanged during the treatment; repeated B-mode ultrasound tests indicated eight of nine plaques remained unchanged, while one showed plaque size reduction. Quantitative analysis demonstrated that, TRK-100 significantly reduced the ADP aggregation (1 microM) from 55.2 +/- 21.3% to 24.0 +/- 14.7% (+/- SD; p less than 0.05) and the platelet accumulation index (25.7 +/- 17.2% vs 10.4 +/- 10.4%; p less than 0.05). However, there was no significant reduction in plaque scores during TRK-100 therapy compared with the baseline (2.70 +/- 2.75 mm vs 2.51 +/- 2.58 mm). The data obtained suggested that short-term TRK-100 therapy has an inhibitory effect on platelet accumulation in carotid atheroma but does not cause significant changes in plaque size.

Topics: Administration, Oral; Aged; Arteriosclerosis; Blood Platelets; Carotid Artery Diseases; Epoprostenol; Female; Humans; Male; Middle Aged; Platelet Aggregation Inhibitors; Thrombosis

Beraprost sodium (sodium (+/-)-(1R*,2R*,3aS*,8bS*)-2,3,3a,8b-tetrahydro-2- hydroxy-1-[(E)-(3S*)-3-hydroxy-4-methyl-1-octen-6-ynyl]-1H- cyclopenta[b]benzofuran-5-butyrate, TRK-100) is a chemically and biologically stable epoprostenol analogue which possesses both potent antiplatelet and peripheral vasodilating actions. Its effect on obstruction of the peripheral artery was studied in three different models: 1. acute thrombosis induced by electrical-stimulation of the femoral artery in rabbits, 2. occlusion induced by intra-arterial injection of sodium laurate in rats and 3. tail gangrene induced by subcutaneous injections of both ergotamine and epinephrine in rats. Oral administration of beraprost sodium resulted in suppression of thrombus formation in the acute thrombosis model, marked improvement of macroscopic and histological observations in the laurate-occlusion model and inhibition of tail gangrene extension. In contrast, ticlopidine improved thrombus formation in the acute thrombosis model and slightly improved histological observation in the laurate-occlusion model, but not in the tail gangrene model. Cilostazol suppressed lesions in the acute thrombosis model, but not in the tail gangrene model. These findings suggest that beraprost sodium may be very useful clinically for the therapy of peripheral circulation insufficiency diseases such as Buerger's disease and Raynaud's disease.

Topics: Acute Disease; Animals; Arterial Occlusive Diseases; Electric Stimulation; Epinephrine; Epoprostenol; Ergotamine; Female; Gangrene; Lauric Acids; Male; Platelet Aggregation Inhibitors; Rabbits; Rats; Rats, Inbred Strains; Regional Blood Flow; Tail; Thrombosis