taprostene and Coronary-Disease

Prostaglandins and prostacyclin are potent vasodilators with marked hemodynamic effects, i.e., both improve cardiac function and possibly cause myocardial ischemia. In order to assess the stable prostacyclin analogon taprostene (T) we first performed an open preliminary study with increasing T-doses (6.5-50 ng/kg/min) and, secondly a double-blind crossover study versus placebo to investigate its influence on ischemic ST-segment depression during exercise stress testing under continuous T-infusions of 25 ng/kg/min (in one case 12.5 ng/kg/min). Eleven of 12 normotensive male patients (age 40 to 60, mean 52.8 +/- 8.4 years) suffering from angiographically proven coronary heart disease and stable angina pectoris completed the study. T was well tolerated, even under increasing doses, and blood pressure and the ECG parameters did not change. The double-blind study revealed no variation in the extent of ischemic ST-segment depression when compared to placebo, and all other ECG parameters as well as the blood pressure remained unaffected. Thus, myocardial ischemia cannot be ruled out completely under T, but earlier clinical findings may be confirmed characterizing T as a marked cytoprotective agent and, to a less degree, as a potent vasodilator.

Topics: Adult; Aged; Cardiovascular Agents; Coronary Circulation; Coronary Disease; Dose-Response Relationship, Drug; Double-Blind Method; Electrocardiography; Epoprostenol; Exercise Test; Hemodynamics; Humans; Male; Middle Aged; Myocardial Ischemia

Thirty patients with ischaemic peripheral vascular disease and intermittent claudication were randomly allocated to receive either placebo or taprostene, a chemically stable prostacyclin analogue, intravenously at a rate of 25 ng/kg/min for 6 hours daily on 5 consecutive days. Taprostene produced a significant (p less than 0.05) increase in absolute walking time compared to placebo on one day after infusion and at 1, 4 and 8 weeks (14% vs 2.8%) later. Taprostene also produced a significant (p less than 0.05) increase in the pain-free walking time compared to placebo in the follow-up period (8 weeks after infusion: 23% vs 3.8%). During the infusion period systolic and diastolic blood pressure decreased (p less than 0.05) and heart rate was accelerated (p less than 0.05) in the taprostene treated group whereas no change was monitored in the placebo group. The ankle/brachial Doppler index was unaffected by taprostene. The platelet half-life was significantly (p less than 0.05) prolonged following taprostene-infusion (72.6 +/- 9.35 vs 77.9 +/- 7.44 hours). However, no change on platelet half-life was found in the placebo group (p less than 0.05). Various measures of platelet function parameters followed in vitro (ADP-induced aggregation, platelet sensitivity to PGI2, PGE1, PGD1 and taprostene, concentrations of platelet factor 4 and beta-thromboglobulin) showed no change with taprostene. Measures of circulating platelet aggregates and endothelial cells count showed no changes during the 2 months follow-up period too. It is assumed that taprostene may be of clinical benefit in patients with ischaemic peripheral vascular disease. However, future investigations have to be carried out to assess the optimal dose regime.

Topics: Alprostadil; Blood Platelets; Blood Pressure; Clinical Trials as Topic; Coronary Disease; Double-Blind Method; Epoprostenol; Exercise; Humans; Male; Middle Aged; Prostaglandin D2

The effects of low dose human superoxide dismutase and low dose taprostene, a stable analogue of prostacyclin, were investigated separately and together in a model of myocardial ischemia (1.5 h) with reperfusion (4.5 h) in open chest, anesthetized cats. Taprostene (60 ng/kg per min), human superoxide dismutase (0.25 mg/kg per h), both agents together, or their vehicle, were infused intravenously in cats starting 0.5 h after occlusion of the left anterior descending coronary artery. Neither low dose taprostene nor low dose human superoxide dismutase exerted any endothelial or myocardial protection in this model. However, the two agents together showed a significant endothelial and myocardial protection in cats with myocardial ischemia and reperfusion. Compared with cats that were untreated or received only taprostene or human superoxide dismutase, cats receiving both agents exhibited a lower plasma creatine kinase activity at every time point observed after reperfusion, a reduced area of cardiac necrosis (7 +/- 2% vs. 21 +/- 5% area at risk, p less than 0.001), lower myeloperoxidase activity in the ischemic region (p less than 0.01) and a significant preservation of vasorelaxant responses of left anterior descending coronary rings to endothelium-dependent vasodilators, acetylcholine (p less than 0.001) and A-23187 (p less than 0.001). Taprostene appears to act additively with human superoxide dismutase to inhibit neutrophil adherence and activation and to inactivate superoxide radicals, and thus reduce cellular injury 4.5 h after reperfusion of the ischemic heart. Use of this agent may allow low doses of superoxide dismutase to be used more effectively in early myocardial ischemia.

Topics: Animals; Cardiovascular Agents; Cats; Coronary Disease; Drug Evaluation, Preclinical; Drug Synergism; Drug Therapy, Combination; Epoprostenol; Humans; Male; Myocardial Reperfusion Injury; Myocardium; Prostaglandins, Synthetic; Superoxide Dismutase

The effects of taprostene, a synthetic prostacyclin analogue, were investigated in a 6-hour model of myocardial ischemia (MI) with reperfusion in anesthetized cats. Taprostene (100 ng/kg/min) was infused intravenously starting 30 minutes postocclusion of the left anterior descending coronary artery followed by reperfusion 1 hour later, and the cats were observed for an additional 4.5 hours. Taprostene infusion resulted in significantly lower plasma creatine phosphokinase activities at every time from 3 to 6 hours for the MI + taprostene group compared with the MI + vehicle group and were not significantly different when compared with sham MI controls. The areas at risk, expressed as a percentage of the total left ventricular weights, were not significantly different between the MI groups. However, the necrotic area expressed as a percentage of the myocardial area at risk was significantly lower in the taprostene-treated cats compared with the untreated MI group (p less than 0.01). Cardiac myeloperoxidase activities indicated that significantly fewer neutrophils were attracted to the area at risk and to the ischemic zone of the MI + taprostene cats when compared with the MI cats given only the vehicle. Data from isolated left anterior descending coronary artery ring preparations removed from hearts after 6 hours of ischemia indicated that the endothelium was damaged by ischemia-reperfusion injury in the untreated cats. However, endothelial dysfunction was not observed in circumflex coronary arteries of ischemic cats or in coronary rings isolated from MI + taprostene cats. Thus, taprostene exerted a significant cardioprotection in cats subjected to ischemia and reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Acetylcholine; Animals; Cats; Coronary Disease; Coronary Vessels; Creatine Kinase; Electrocardiography; Endothelium, Vascular; Epoprostenol; Heart; Hemodynamics; Male; Myocardial Reperfusion; Myocardium; Peroxidase; Prostaglandin Endoperoxides, Synthetic; Vasodilation

In open chest dogs myocardial ischemia was induced by formation of an occlusive thrombus in the left anterior circumflex artery (LCX). Reperfusion of the LCX was achieved by infusion of the fibrin specific recombinant single-chain urokinase-type plasminogen activator (r-scu-PA). The myocardial salvage by r-scu-PA alone and in combination with the epoprostenol (prostacyclin) analog taprostene (CG 4203) was compared. There were four experimental groups: group 1 (n = 4) did not receive any treatment after LCX thrombosis; in group 2 (n = 9) at 100 min after LCX thrombosis r-scu-PA (20 micrograms.kg-1.min-1 i.v. for 30 min) was infused; in groups 3 and 4 treatment with taprostene started concomitantly with r-scu-PA infusion. The taprostene infusions lasted for 120 min and the doses were 0.1 microgram.kg-1.min-1 in group 3 (n = 6) and 0.215 microgram.kg-1.min-1 in group 4 (n = 6). Time to r-scu-PA-induced recanalisation ranged from 18-22 min with no significant difference between groups 2-4. Percent of left ventricle at risk did not differ between the groups. Infarct size as percent of the risk zone was 48.3 +/- 7.7 in group 1, 25.3 +/- 3.7 in group 2, 21.3 +/- 6.5 in group 3 and 17.1 +/- 3.5 in group 4 (p less than 0.05 groups 2-4 vs group 1). Incidence of ectopic beats increased after r-scu-PA-induced reperfusion in groups 2-4, but was significantly reduced by taprostene.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Arrhythmias, Cardiac; Coronary Disease; Coronary Thrombosis; Creatine Kinase; Dogs; Epoprostenol; Female; Hemodynamics; Male; Myocardial Infarction; Myocardial Reperfusion; Myocardium; Plasminogen Activators; Recombinant Proteins; Urokinase-Type Plasminogen Activator

[(5Z,13E,9 alpha,11 alpha,15S)-2,3,4-Trinor - 1,5 - inter-m - phenylene - 6,9 - epoxy - 11,5 - dihydroxy - 15 - cyclohexyl - 16,17,18,19,20-pentanor]- prosta-5,13-dienoic acid (sodium salt) (CG 4203) is a new stable epoprostenol (prostacyclin) analogue with a relative platelet antiaggregatory potency of 0.46 (ADP aggregation in vitro) and a hypotensive potency of 0.14 (anaesthetized rat i.v.) as compared to epoprostenol. In isolated perfused rat hearts, CG 4203 (4.64 X 10(-9) mol/l) significantly attenuated arrhythmias and loss of left ventricular creatine kinase (CK) activity observed in control hearts after 30 min perfusion with hypoxic and 30 min reperfusion with oxygenated Krebs-Ringer solution. In anaesthetized rats, CG 4203 (1.0 microgram X kg-1 X min-1 i.v.) significantly reduced incidence of ventricular fibrillation and increase in plasma CK activity after ligation of the left coronary artery. Infusion of 1.0 and 2.15 micrograms X kg-1 X min-1 CG 4203 i.v. in anaesthetized rats dose-dependently inhibited electrocardiographic changes, i.e. ST depression observed after i.v. injection of 1.0 IU X kg-1 vasopressin. In rat models of sustained myocardial hypoxia, myocardial infarction, and transient cardiac ischemia, CG 4203 thus exerts cardioprotective effects which, depending on the model considered, may be ascribed to either its vasodilatory, coronary dilatory, antiaggregatory or epoprostenol-like cytoprotective activity.

Topics: Animals; Cardiovascular Agents; Coronary Disease; Creatine Kinase; Epoprostenol; In Vitro Techniques; Male; Myocardial Contraction; Nitroglycerin; Oxygen; Perfusion; Rats; Rats, Inbred Strains; Vasopressins