iloprost and Myocardial-Infarction

Type Sphosphodiesterase inhibitors (FDEI-5) used to be applied as the main drugs for treatment of erectile dysfunction. At present, this pharmacological group is being studied intensively in various fields of clinical medicine, such as pulmonology, cardiology, gastroenterology, gynecology etc. Part II of this system literature review is dedicated to analysis of the results of such application. In many randomized and non-randomized controlled studies sildenafil decreased pulmonary arterial pressure (independently of etiology) and pulmonary vascular resistance; it could be successfully combined with nitric oxide, illoprost, or epoprostenolol. Clinical studies have also demonstrated an increase in physical load tolerance, optimization of PAH studies according to NYHA functional classes, and good tolerance to the drug. In the recent years, antiischaemic effects of FDEI-5 and their ability to inhibit apoptosis have been proved It is possible to draw the conclusion that nature created a universal phosphodiesterase mechanism for the interconnection of biochemical processes that provide the vital activity of the cell and organism. The fact that more than 15 controlled studies of clinical application of sildenafil not for treatment of erectile dysfunction have been planned and commenced confirms the importance of further studies of this mechanism. Further analysis of the results will show how universal this mechanism is.

Topics: 3',5'-Cyclic-GMP Phosphodiesterases; Bronchodilator Agents; Cyclic Nucleotide Phosphodiesterases, Type 5; Drug Therapy; Drug Therapy, Combination; Forecasting; Heart Failure; Humans; Hypertension, Pulmonary; Iloprost; Myocardial Infarction; Nitric Oxide; Phosphodiesterase Inhibitors; Piperazines; Purines; Sildenafil Citrate; Sulfones; Treatment Outcome; Vasodilator Agents

Coronary reocclusion complicates the thrombolytic therapy of acute myocardial infarction despite the routine use of aspirin. This is consistent with experimental studies demonstrating that multiple agonists, in addition to thromboxane A2, mediate the platelet activation underlying reocclusion. Consequently, a more potent antiplatelet therapy with a broader spectrum of activity than aspirin may be required in this setting. Prostacyclin and its more stable analogue, iloprost, inhibit platelet aggregation to all known agonists and exert an additional effect over aspirin alone. Experiments in animal models have demonstrated, however, that iloprost increases the clearance of tissue-type plasminogen activator (t-PA) and impairs thrombolysis in vivo. This study examines whether a similar interaction occurs in humans.. Twelve patients with acute myocardial infarction received t-PA intravenously, 60 mg in the first hour and a maintenance infusion of 13.3 mg/hr for 3 hours. Patients were assigned in a double-blind fashion to iloprost (2 ng/kg/min) or placebo following the initial 90 minutes of the maintenance infusion of t-PA. Iloprost decreased mean arterial blood pressure (-10 +/- 2.9 mm Hg, p less than 0.05) but did not alter heart rate. Steady-state plasma iloprost concentration was 591 +/- 64 pmol/l. At this concentration, iloprost markedly inhibited platelet aggregation in vitro, particularly in the presence of aspirin. Steady-state clearance of t-PA was unchanged by iloprost (454 +/- 65 versus 443 +/- 136 ml/min in controls, p = NS). Furthermore, neither elimination kinetics nor plasma protein binding of t-PA was altered by iloprost.. At plasma levels that exert a potent antiplatelet effect, iloprost did not alter the pharmacokinetics of t-PA in men. Prostacyclin analogues may prove useful as an adjunct to plasminogen activators, particularly in patients at high risk for thrombotic reocclusion.

Topics: Acute Disease; Enzyme-Linked Immunosorbent Assay; Hemodynamics; Humans; Iloprost; Male; Myocardial Infarction; Placebos; Platelet Aggregation; Platelet Aggregation Inhibitors; Tissue Plasminogen Activator

Despite significant advances in medicine, mortality due to cardiovascular disease is not yet preventable. We investigated the amounts of elabela (ELA) and apelin, synthesized by cardiomyocytes, and changes of these compounds in cardiac tissue and circulation after administration of iloprost (ILO) and sildenafil (SIL) in rats with induced myocardial ischemia (MI). We also investigated a connection with circulating troponin-I, creatine kinase (CK), creatine kinase-myocardial band (CK-MB) and nitric oxide (NO), and total anti-oxidant (TAS)/total oxidant status (TOS). We established eight study groups of five rats each. Group 1, sham, was given only physiologic serum; group 2, ILO; group 3, SIL; group 4, ILO + SIL; group 5, MI; group 6, MI + ILO; group 7, MI + SIL; group 8, MI + ILO + SIL. Troponin-I, CK, CK-MB and TAS-TOS were investigated using an autoanalyzer. NO, ELA and apelin were analyzed by ELISA. Tissue apelin and ELA expressions and localizations were determined by immunohistochemistry. The MI group compared to the control (sham) group showed that ELA, apelin, troponin-I, CK, CK-MB, NO and TOS levels were elevated significantly. Concentrations of these factors increased in MI, but decreased after ILO and SIL administration. The largest decrease of TOS was identified in the ILO + SIL group. ELA and apelin may be novel indicators of MI and administration of ILO and SIL, individually or together, may be useful for treating MI.

Topics: Acute Coronary Syndrome; Animals; Antioxidants; Biomarkers; Creatine Kinase; Iloprost; Male; Myocardial Infarction; Nitric Oxide; Rats, Sprague-Dawley; Sildenafil Citrate

Topics: Angioplasty, Balloon, Coronary; Embolism, Cholesterol; Humans; Hyperbaric Oxygenation; Iloprost; Male; Middle Aged; Myocardial Infarction; Necrosis; Peripheral Vascular Diseases; Platelet Aggregation Inhibitors; Stents; Tomography, X-Ray Computed

The association of vasoplegic shock and myocardial infarction in a patient under iloprost treatment for critical ischemia of the lower limbs has not previously been reported.. A 56 year-old man suffering from type 2 diabetes, hypertension and dyslipidemia developed critical ischemia of the right leg and was treated with iloprost. On the 19th day of infusion, he developed a vasoplegic shock with myocardial infarction. The shock resolved and he recovered from the infarction.. This case report indicates the need for reinforced blood pressure and electrocardiographic monitoring in diabetes patients treated with iloprost.

Topics: Diabetes Mellitus, Type 2; Follow-Up Studies; Humans; Iloprost; Ischemia; Leg; Male; Middle Aged; Myocardial Infarction; Shock, Cardiogenic; Time Factors; Vasodilator Agents

Peripheral vascular occlusive disease (PAOD) is frequently seen in patients suffering from coronary heart or cerebrovascular disease and is, considered as a prognostic predictor for the morbidity and mortality of this patient group. Thus, secondary antithrombotic and antiplatelet prophylaxis in these patients is not limited to achievement of long-term patency of the revascularized or recanalized arterial segment, but plays as well a pivotal role for the prevention of myocardial infarction and stroke. Generally, claudicants as well as patients undergoing percutaneous transluminal angioplasty (PTA), supragenicular femoro-popliteal artificial bypass surgery, aortofemoral, iliaco-femoral unilateral bypass, or aortobifemoral Y-graft implantation with unimpaired arterial outflow are treated life-long with low dose acetylsalicylic acid (ASA) 75-250 mg. On the other hand, those undergoing axillo-femoral, femoro-femoral crossover, aorto-profundal or femoro-popliteal infragenicular and femoro-distal venous bypass surgery should be treated with vitamin K antagonists. The role of Clopidogrel in secondary prevention after peripheral revascularization and recanalization still needs to be defined.

Topics: Administration, Oral; Angioplasty, Balloon; Anticoagulants; Arterial Occlusive Diseases; Aspirin; Blood Vessel Prosthesis; Clopidogrel; Confidence Intervals; Dipyridamole; Drug Therapy, Combination; Embolectomy; Fibrinolytic Agents; Heparin; Heparin, Low-Molecular-Weight; Humans; Iloprost; Intermittent Claudication; Leg; Meta-Analysis as Topic; Middle Aged; Multicenter Studies as Topic; Myocardial Infarction; Peripheral Vascular Diseases; Platelet Aggregation Inhibitors; Randomized Controlled Trials as Topic; Risk Factors; Stroke; Thrombectomy; Ticlopidine; Time Factors; Vitamin K

Topics: Aged; Aged, 80 and over; Catheterization; Coronary Angiography; Coronary Artery Bypass; Embolism, Cholesterol; Female; Humans; Iloprost; Male; Middle Aged; Myocardial Infarction; Platelet Aggregation Inhibitors; Vasodilator Agents

Nitric oxide and prostacyclin are endothelial-derived vasodilators which inhibit platelet aggregation in a synergistic manner. Experiments were designed to examine whether 3-morpholino-sydnonimine (SIN-1) and iloprost have synergistic cardioprotective actions and whether their effects on infarct size are related to inhibition of platelet aggregation. Anaesthetized rabbits (n = 9-10 per group) were subject to 40 min myocardial ischaemia followed by 3 h reperfusion. Infarct size (percentage of area at risk) was not altered significantly by 3 microg kg(-1) min(-1) SIN-1 (29.7 +/- 1.9%), but was reduced by 0.03 microg kg(-1) min(-1) iloprost (24.6 +/- 1.6%) and to a greater extent by the combination of SIN-1 and iloprost (18.8 +/- 1.7%), compared to controls (33.6 +/- 4.7%). In control rabbits, there were reductions in the ex vivo aggregation of platelets in response to ADP or collagen after ischaemia and reperfusion. SIN-1 and iloprost caused some alterations in platelet responses, but combined administration of both drugs did not produce greater effects. Although the reduction in myocardial infarct size was greatest with both drugs, this did not appear to be a synergistic interaction and was not dependent on the effects of the drugs on haemodynamics or platelet aggregation.

Topics: Animals; Arrhythmias, Cardiac; Creatine Kinase; Drug Synergism; Electrocardiography; Hemodynamics; Iloprost; Male; Molsidomine; Myocardial Infarction; Platelet Aggregation; Rabbits

A chemically stable prostacyclin analog, KP-10614 [(4Z,16S)-4, 5, 18, 18, 19, 19-hexadehydro-16,20-dimethyl-delta 6(9 alpha)-9(O)-methano-prostaglandin I1], was synthesized to increase the cytoprotective activity and to decrease the hypotensive activity. We have reported that KP-10614, infused i.v. at a dose of 3 ng/kg/min for 4 hr, inhibited platelet functions and reduced the experimental cardiac infarct size significantly, but did not change hemodynamic parameters and the ischemic area of the heart induced by ligation of the left descending coronary artery in rats. Accordingly, we thought that myocardial protective effects of KP-10614 might be based on the inhibition of platelet functions and cellular metabolism produced by platelets at the site of tissue injury. KP-10614 suppressed leukotriene B4 synthesis by N-formyl-methionyl-leucyl-phenylalanine-stimulated polymorphonuclear leukocytes, which was enhanced by thrombin-treated platelets in a concentration-dependent manner, even though KP-10614 did not suppress leukotriene B4 synthesis by N-formyl-methionyl-leucyl-phenylalanine-stimulated polymorphonuclear leukocytes separately in vitro. Moreover in in vivo studies, KP-10614, which was infused at a dose of 3 ng/kg/min for 4 hr, suppressed leukotriene B4 content, myeroperoxidase activity and polymorphonuclear leukocyte counts in myocardial tissues that were infarcted by ligation of the left descending coronary artery for 4 hr in rats. These data supported the hypothesis that KP-10614, a new prostacyclin analog, had protective effects on myocardial infarction in rats by suppressing the platelet-polymorphonuclear leukocyte interaction at the site of tissue injury in vivo.

Topics: Animals; Blood Platelets; Cell Communication; Cells, Cultured; Disease Models, Animal; Epoprostenol; Fibrinolytic Agents; Iloprost; Leukotriene B4; Male; Myocardial Infarction; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Peroxidase; Rabbits; Rats; Rats, Sprague-Dawley

The potential therapeutic value of a new prostacyclin analogue, (4z, 16s)-4,5,18,18,19,19-hexadehydro-16,20-dimethyl-delta 6(9a)- 9-(O)-methano-PGI1 (KP-10614), was studied in acute myocardial infarction in rats. Myocardial infarction was induced by ligation of the left coronary artery and ischemic injury was followed up to 4 h. The infarct size, evaluated by the area unstained by 2,3,5-triphenyltetrazolium chloride, reached 41.1 +/- 1.4% of the left ventricle at 4 h. KP-10614 (3 ng/kg/min x 4 h) reduced the infarct size at 4 h significantly (26.5 +/- 2.9%). At the same dose, KP-10614 inhibited ADP-induced ex vivo platelet aggregation significantly (21.5 +/- 4.0% of the control aggregation), but did not alter the arterial blood pressure or heart rate. To assess the role of platelets in myocardial infarction, circulating platelets were reduced by about 95% with rabbit antiserum to rat platelets. In platelet-depleted rats, the infarct size decreased significantly to 24.1 +/- 4.6% of the left ventricle at 4 h. These results suggest that platelets play an important role in expression of myocardial ischemic injury resulting from coronary artery occlusion in rats, and the ability of KP-10614 to decrease the infarct size appeared to be attributable, at least in part, to the inhibition of platelet aggregation or cellular metabolic effects produced by platelets at the site of tissue injury.

Topics: Animals; Blood Platelets; Epoprostenol; Fibrinolytic Agents; Hemodynamics; Iloprost; Leukocyte Count; Male; Molecular Structure; Myocardial Infarction; Myocardial Ischemia; Platelet Aggregation; Rats; Rats, Sprague-Dawley

The role of inflammation in reperfused, ischaemic myocardium was assessed morphologically in 39 porcine hearts after 24 h (n = 23) and 72 h (n = 16) of reperfusion and after different antiphlogistic treatments. The left anterior descending coronary artery (LAD) was occluded distally for 45 min. Seven pigs received BW755C (10 mg kg-1) i.v. prior to ischaemia (A), eight pigs were given the same dose before 24 h of reperfusion (B), and eight pigs were treated with iloprost (25 ng kg-1 min-1) i.v. before occlusion and continuously for 72 h (C). Two groups of eight pigs each served as controls for 24 h (D) and 72 h (E) of reperfusion. Infarct sizes were determined, myocardium was investigated by light microscopy, and polymorphonuclear leucocytes (PMNs) and macrophages were quantitated after histo- and immunohistochemical staining. Jeopardized myocardium contained 129 neutrophils mm-2 and 120 macrophages mm-2 (D) vs 10 neutrophils mm-2 and 290 macrophages mm-2 (E). Neutrophils and infarct sizes were only significantly decreased in group A (68 neutrophils mm-2, 30% reduction of infarct size). Macrophages infiltration was not significantly affected for all treatment groups (A, B, C). It is concluded that myocardial infarct sizes are neutrophil-mediated postischaemic tissue injury can be reduced by BW755C applied prior to ischaemia. Neutrophil-mediated myocardial injury is unlikely to occur beyond 3 days of reperfusion.

Topics: 4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine; Animals; Female; Iloprost; Inflammation; Macrophages; Male; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Neutrophils; Time Factors

The effect of iloprost (Schering AG, Berlin), a stable prostacyclin analogue, was investigated in ischemic, reperfused porcine hearts. The left anterior descending coronary artery (LAD) was distally occluded in 18 pigs for 45 min followed by 3-d of reperfusion. Nine pigs were continuously treated with iloprost at a dose of 25 ng/kg per min. Treatment was started as intracoronary infusion into the proximal LAD 10 min before occlusion. The intercoronary infusion was replaced by an intravenous infusion after 45 min of reperfusion, which was continued until the end of the experiment. Infarct size was determined as the ratio of infarcted (tetrazolium stain) to ischemic myocardium (dye technique). Regional systolic shortening was assessed by sonomicrometry. Myocardial concentrations of adenosine triphosphate were evaluated at the end of the experiment. Generation of free radicals by stimulated polymorphonuclear neutrophils was determined by luminol-enhanced chemiluminescence. Histologic and immunohistologic techniques were applied to characterize the myocardial inflammatory response. Global hemodynamics did not differ between the two groups. Neither infarct size (control group 68 +/- 18%, treated group 74 +/- 14%), recovery of systolic shortening (control group 3 +/- 6%, treated group 6 +/- 6%), nor myocardial adenosine triphosphate concentrations were improved by iloprost treatment. Myocardial inflammatory response remained unaffected by this treatment. The capacity of coronary venous, stimulated polymorphonuclear neutrophils to generate free radicals was slightly suppressed in the treated group before ischemia, at the end of ischemia and during early reperfusion. In this preparation, iloprost did not exhibit any beneficial effect on infarct size, recovery of systolic shortening and myocardial adenosine triphosphate concentrations.

Topics: Adenosine Triphosphate; Animals; Female; Free Radicals; Hemodynamics; Iloprost; Male; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Neutrophils; Swine; Ventricular Fibrillation

We administered iloprost, a stable prostacyclin mimetic, 27 nM, to isolated and perfused rabbit hearts submitted, after 60 min of equilibration, to an ischaemic period (60 min at a coronary flow of 1 ml/min) followed by a period of reperfusion (30 min at a coronary flow of 25 ml/min). Iloprost was delivered at different times during the experimental protocol: 60 min before ischaemia, at the onset and after 30 min of ischaemia and only during reperfusion. The iloprost cardioprotective effect was evaluated in terms of recovery of left ventricular pressure developed during reperfusion, creatine phosphokinase (CPK) and noradrenaline release, mitochondrial function (expressed as yield, RCI (respiratory control index), QO2, ADP/O), ATP and creatine phosphate (CP) tissue contents, calcium homeostasis and by measuring several parameters of oxidative stress: reduced and oxidized glutathione release and tissue contents, Mn and Cu-Zn superoxide dismutase activities; glutathione reductase and peroxidase activities. Our data show that the cytoprotective action of iloprost is closely related to the time of administration. Optimal myocardial preservation was achieved when it was given before or at the onset of ischaemia. Iloprost administration 30 min after the onset of ischaemia was still beneficial, although to a lesser extent. Iloprost lost its protective effect when given only on reperfusion. The data suggest that the iloprost cardioprotective effect is related to maintainance of membrane integrity.

Topics: Adenosine Triphosphate; Animals; Calcium; Chromatography, High Pressure Liquid; Creatine Kinase; Glutathione; Iloprost; Male; Mitochondria, Heart; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Norepinephrine; Oxygen Consumption; Rabbits; Thrombolytic Therapy; Time Factors

Patients with failure of infarct-related artery recanalization after thrombolytic therapy have a poor clinical outcome. These patients have been considered for rescue angioplasty 90 min after thrombolytic therapy at the time of emergency catheterization in the course of five Thrombolysis and Angioplasty in Myocardial Infarction (TAMI) trials. The outcome of 776 patients with patent infarct-related vessels after emergency catheterization was analyzed--607 with thrombolysis-mediated patency of the infarct-related vessel and 169 with patency achieved by angioplasty. Baseline characteristics of the thrombolysis and angioplasty patency groups were similar except for a higher acute left ventricular ejection fraction (51.3% versus 48.2%) in the thrombolysis group (p = 0.003). Seven to 10 day left ventricular ejection fraction was higher (52.3% versus 48.1%), infarct zone functional recovery was greater (0.44 versus 0.21 standard deviation/chord, or 18% versus 7%, p = 0.001) and reocclusion was less (11% versus 21%) in the thrombolysis compared with the angioplasty group. Despite these differences, angioplasty patency was associated with the same low in-hospital mortality rate (5.9% versus 4.6%) and long-term mortality rate (3% versus 2%) as thrombolysis patency. Reocclusion adversely affected the mortality rate and ventricular functional recovery. Technical failure of rescue angioplasty was associated with a much higher mortality rate than was technical success (39.1% versus 5.9%). Thrombolysis patency was preferable to angioplasty patency after thrombolytic therapy in acute myocardial infarction, but both were associated with the same low in-hospital and long-term mortality rates, suggesting that rescue angioplasty is beneficial in some patients with failure of infarct-related artery recanalization after thrombolytic therapy.

Topics: Angioplasty, Balloon, Coronary; Female; Follow-Up Studies; Humans; Iloprost; Male; Middle Aged; Myocardial Infarction; Recombinant Proteins; Recurrence; Thrombolytic Therapy; Time Factors; Tissue Plasminogen Activator; Urokinase-Type Plasminogen Activator; Vascular Patency; Vasodilator Agents

Current limitations of recombinant tissue-type plasminogen activator (rt-PA) therapy for acute myocardial infarction include failure to achieve recanalization in 25% of patients, reocclusion and reperfusion injury. Iloprost, a stable analogue of prostacyclin (PGI2), has been demonstrated to facilitate thrombolysis and reduce myocardial stunning in experimental models. To evaluate combined therapy, rt-PA (100 mg 3 h) and Iloprost (2 ng/kg per min for 48 h) were administered to 25 patients and then rt-PA alone (same dose) was given to an additional 25 patients with evolving myocardial infarction. At 90 min after drug administration, infarct-related vessel patency was observed in 11 (44%) of 25 who received rt-PA plus Iloprost compared with 15 (60%) of 25 who received rt-PA alone (p = 0.26). At 1 week, reocclusion had occurred in 3 (14%) of 21 patients who received combined therapy compared with 6 (26%) of 23 patients treated with rt-PA alone (p = 0.46). Ejection fraction increased significantly from baseline to 7 days for rt-PA alone whereas it decreased with combined therapy (rt-PA alone whereas it decreased with combined therapy (rt-PA alone: 47.3 +/- 11.5% at baseline to 50.4 +/- 9.8% at 7 days; rt-PA plus Iloprost: 51.3 +/- 10.1% at baseline to 49.0 +/- 9.4% at 7 days; difference between groups p = 0.05). At 4 h after therapy, fibrinogen decreased 33% for rt-PA plus Iloprost compared with a 52% for rt-PA alone (p = 0.001). Fibrinogen degradation products increased 60% more for rt-PA alone than for rt-PA plus Ilprost. Thus, the combination of rt-PA plus Iloprost at the doses employed did not improve immediate or follow-up coronary artery patency or left ventricular functional recovery compared with that achieved with rt-PA alone.

Topics: Cardiovascular Agents; Drug Therapy, Combination; Epoprostenol; Female; Humans; Iloprost; Male; Middle Aged; Myocardial Infarction; Pilot Projects; Recombinant Proteins; Recurrence; Stroke Volume; Thrombolytic Therapy; Time Factors; Tissue Plasminogen Activator; Vascular Patency

Topics: Animals; Cardiovascular Agents; Coronary Disease; Creatine Kinase; Epoprostenol; Iloprost; Myocardial Infarction; Myocardial Reperfusion Injury; Swine

In this study we attempted to determine whether administration of iloprost (ZK 36374), a chemically stable prostacyclin analogue, would reduce infarct size after experimental coronary artery occlusion and reperfusion. One hour of coronary artery occlusion was performed in 28 open-chest, anesthetized rabbits++, followed by 5 hours of reperfusion. Two minutes after occlusion, 99mTc-labeled albumin microspheres were injected into the left atrium for later assessment of the area at risk of infarction. Fifteen minutes after occlusion animals were randomly assigned to either the treatment group (iloprost, 1.2 micrograms/kg/min intravenously for 6 hours; n = 14) or the control group (n = 14). In vitro platelet aggregation was inhibited in rabbits receiving iloprost. In 10 rabbits (five treated and five control) regional myocardial blood flow was also measured by means of differentially labeled radioactive microspheres. Infarct size was significantly smaller in treated rabbits (53.6 +/- 4.1% of the risk zone vs 89.4 +/- 3.8% in control rabbits; p less than 0.001). Flow to the nonischemic myocardium was higher in treated animals, that is, 1.87 +/- 0.20 ml/min/gm of tissue 50 minutes after occlusion and 1.90 +/- 0.20 ml/min/gm of tissue 4 hours after reperfusion, compared with 1.54 +/- 0.20 and 1.64 +/- 0.30 ml/min/gm of tissue, respectively, in control rabbits (p less than 0.01). Collateral flow to the ischemic region was not affected by the drug. Mean arterial blood pressure, heart rate, and pressure-rate product in treated rabbits were not significantly different from values in control rabbits. In conclusion, administration of iloprost reduced myocardial infarct size in this model of myocardial ischemia and reperfusion in absence of major hemodynamic effects.

Topics: Animals; Cardiovascular Agents; Coronary Circulation; Coronary Disease; Disease Models, Animal; Drug Administration Schedule; Epoprostenol; Hemodynamics; Iloprost; Male; Myocardial Infarction; Platelet Aggregation; Rabbits; Random Allocation

Topics: Animals; Cardiovascular Agents; Coronary Disease; Drug Evaluation, Preclinical; Epoprostenol; Heart; Iloprost; Myocardial Infarction; Myocardium; Necrosis; Rabbits; Radionuclide Imaging; Technetium Tc 99m Aggregated Albumin

The cardio-protective effects of neutrophil depletion or inhibition of neutrophil activation early in the course of myocardial reperfusion has been established. Whether these treatments would be effective during extended periods of reperfusion has not been ascertained. Open-chest anesthetized dogs were subjected to left circumflex artery (LCX) occlusion for 90 minutes followed by 72 hours of reperfusion. Dogs were randomized into one of four groups: 1) control; 2) Ilo-2 (iloprost 100 ng/kg/min administered via the left atrium beginning 10 minutes after LCX occlusion and continuing 2 hours into reperfusion); 3) Ilo-48 (iloprost 100 ng/kg/min administered as above until 1 hour after reperfusion then 25 ng/kg/min for 48 hours of reperfusion; or 4) antibody (neutrophil antibody administered before occlusion and 1/2 hourly for 2 hours of reperfusion and then every 24 hours). Myocardial infarct size, as a percentage of the area at risk assessed after 72 hours of reperfusion, was significantly smaller in the antibody-treated group (32.1 +/- 5.0% mean +/- SEM) or Ilo-48 (22.6 +/- 4.0%) treatment group compared with control (48.7 +/- 5.6%) or Ilo-2 (57.6 +/- 5.2%) groups. Regional myocardial blood flow studies demonstrated that all groups developed similar degrees of ischemia. The iloprost-treated groups had lower mean arterial blood pressures during occlusion and reperfusion than groups 1 and 4 (p less than 0.05). Circulating neutrophil counts were increased in groups 1 and 2 at 24 and 48 hours after reperfusion compared to groups 3 and 4 (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Cardiovascular Agents; Cell Count; Coronary Circulation; Coronary Disease; Dogs; Epoprostenol; Hemodynamics; Iloprost; Inflammation; Male; Myocardial Infarction; Myocardial Reperfusion; Myocardial Reperfusion Injury; Myocardium; Neutrophils; Peroxidase; Time Factors

The prostacyclin analogue iloprost (ZK 36374) inhibits neutrophil activation in vitro, reduces neutrophil accumulation in inflammatory skin lesions, and reduces ultimate infarct size in an anesthetized open-chest canine model of regional ischemia and reperfusion. Iloprost (0.1-100 microM) inhibited the in vitro production of superoxide anion by canine neutrophils in a concentration-dependent manner. Iloprost (100 ng/kg/min i.v.) inhibited C5a-induced neutrophil migration into inflammatory skin lesions as assessed by the neutrophil-specific enzyme marker, myeloperoxidase. The myeloperoxidase activity determined 2 hours after the intradermal administration of C5a in each of the groups was control 13.3 +/- 1.8 units/g tissue (n = 12) and iloprost 6.5 +/- 0.9 units/g (n = 12), p less than 0.01. Iloprost was administered to anesthetized open-chest dogs (100 ng/kg/min) 10 minutes after left circumflex coronary artery (LCCA) occlusion and continued during the 90-minute occlusion period and the first 2 hours of reperfusion. Regional myocardial blood flow was similar between treatment groups at baseline, 5 minutes and 80 minutes after LCCA occlusion, and after 1 hour of reperfusion. Infarct size, assessed 6 hours after reperfusion, was reduced by iloprost treatment: 22.4 +/- 3.1% of the area at risk (n = 15) compared with 42.4 +/- 3.3% of control (n = 13), p less than 0.01. Iloprost treatment reduced the accumulation of neutrophils (measured by myeloperoxidase activity) in the ischemic myocardium at the interface between infarcted and noninfarcted tissue: control (n = 9) 9.0 +/- 1.8 units/g tissue, iloprost (n = 6) 2.0 +/- 0.4 units/g, p less than 0.01.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Cardiovascular Agents; Coronary Circulation; Dogs; Epoprostenol; Hemodynamics; Iloprost; In Vitro Techniques; Male; Myocardial Infarction; Myocardium; Neutrophils; Oxygen Consumption; Peroxidase; Superoxides

In 14 patients with acute myocardial infarction, a 24-hour Iloprost infusion was started with a mean delay of 309 +/- 22 minutes from onset of symptoms. Patients were haemodynamically monitored with a pulmonary artery catheter and an arterial cannula. The dose of Iloprost was 1-4 ng kg-1 min-1 and titrated according to blood pressure and systemic vascular resistance. When 2.0-4.0 ng kg-1 min-1 of Iloprost were infused, 5 out of 10 patients required dose reduction due to hypotension, nausea or both. However, in all patients the infusion period was completed as planned. Acute reductions of systolic blood pressure and vascular resistance were seen, whereas stroke volume increased and heart rate remained unchanged. The infusion of Iloprost caused profound inhibition of ADP-induced platelet aggregation but no significant changes in plasma values for platelet-specific proteins or thromboxane B2 were recorded. It is concluded that it was possible to safely administer Iloprost over 24 hours in the early phase of acute myocardial infarction and profound anti-aggregatory effects were observed. These findings should be evaluated in a controlled study.

Topics: Adult; Aged; beta-Thromboglobulin; Cardiovascular Agents; Epoprostenol; Female; Hemodynamics; Humans; Iloprost; Male; Middle Aged; Myocardial Infarction; Platelet Aggregation; Platelet Factor 4; Thromboxane B2

Topics: Animals; Blood Platelets; Coronary Circulation; Coronary Disease; Epoprostenol; Iloprost; Myocardial Infarction; Rabbits

The thromboxane (TX) synthetase inhibitor dazoxiben (80 micrograms/kg X min) and the prostacyclin analogue iloprost (0.6 micrograms/kg X min) were investigated in a cat model of acute myocardial ischaemia (MI) plus reperfusion. The agents were i.v. infused starting 30 min after LAD occlusion until the end of the observation period (5h). Dazoxiben significantly reduced the MI-induced increase in TXB2 and platelet ATP secretion. Dazoxiben did not influence the MI-induced depression in platelet count (PC), the fall in CK-specific activity or the ECG alterations associated with reperfusion whereas iloprost resulted in a nearly complete recovery of these parameters. These data suggest an efficacy of PGI2 administration but not of TX synthetase inhibition in preserving the myocardium from reperfusion injury. These data indicate that reperfusion-induced tissue damage appears not to be a thromboxane-dependent phenomenon.

Topics: Adenosine Triphosphate; Animals; Blood Platelets; Cardiovascular Agents; Cats; Collagen; Disease Models, Animal; Epoprostenol; Iloprost; Imidazoles; Infusions, Parenteral; Myocardial Infarction; Oxidoreductases; Platelet Count; Thromboxane-A Synthase

A number of investigations have reported that prostacyclin or prostacyclin analogues protect the ischaemic myocardium when administered early after myocardial ischaemia. Thus far, there are no reports describing whether these substances exert a cardioprotective effect when administered later than 0.5 h after coronary artery occlusion. Adult cats were subjected to acute coronary artery ligation for 5 h and administered the vehicle or ZK 36 374 (iloprost) (1.19 micrograms X kg-1 X min-1), a prostacyclin analogue, beginning at 0.5, 2 or 4 h. Compared with the MI-vehicle cats, ZK 36 374 prevented a decrease in myocardial creatine kinase specific activity, the loss of free amino nitrogen and the fall in percentage bound cathepsin D in the ischaemic area when infusion was started at 0.5 or 2 h (P less than 0.05). In addition ZK 36 374 started at 4 h still showed a significant protective effect against myocardial creatine kinase specific activity and amino nitrogen concentrations but not against cathepsin D. In a separate group of animals, regional myocardial blood flow and late coronary resistance were determined with radioactive labelled 15 +/- 1 micron microspheres. ZK 36 374 consistently reduced late diastolic coronary vascular resistance and increased coronary blood flow in nonischaemic regions of the myocardium (P less than 0.05) but only attenuated the further increase in late coronary resistance in the ischaemic myocardial regions. The infarcted area (NTB-staining) amounted to 9% of the total left ventricle after 5 h and was not reduced by ZK 36 374 (P greater than 0.05). In conclusion, ZK 36 374 exerted a significant biochemical cardioprotective effect when administered to 0.5, 2 or 4 h. The mechanism of cardioprotection does not appear to be due to increased myocardial perfusion but rather to some direct cellular action whose exact nature has yet to be elucidated.

Topics: Animals; Cardiovascular Agents; Cats; Collateral Circulation; Coronary Circulation; Drug Administration Schedule; Epoprostenol; Hemodynamics; Iloprost; Myocardial Infarction; Myocardium; Platelet Count