calcimycin and Coronary-Disease

Inflammation plays a pivotal role in the pathophysiology of cardiovascular disease, (CVD) and leukotrienes may play a role in atherogenesis. Statins reduce mortality from CVD by reducing LDL cholesterol and potentially by other (pleiotropic) mechanisms. The aim of this study was to investigate if atorvastatin exerts an anti-inflammatory effect by reducing leukotriene B₄ (LTB₄) formation from stimulated neutrophils in patients treated with coronary artery bypass grafting. The study was a randomized, placebo-controlled, double-blinded crossover study. Patients (n=80) were allocated to 80 mg atorvastatin or placebo for 6 weeks before crossing over to the opposite treatment for another 6 weeks. There was no significant correlation between baseline LDL cholesterol levels on formation of LTB₄, and atorvastatin had no effect on LTB₄ formation. Hence, this study does not support any effect of atorvastatin on LTB₄ formation as part of the explanation for its beneficial effect on CVD.

Topics: Aged; Anti-Inflammatory Agents, Non-Steroidal; Atorvastatin; Calcimycin; Calcium Ionophores; Cholesterol, LDL; Combined Modality Therapy; Coronary Artery Bypass; Coronary Disease; Cross-Over Studies; Double-Blind Method; Female; Heptanoic Acids; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypercholesterolemia; Leukotriene B4; Male; Middle Aged; Neutrophil Activation; Neutrophils; Pyrroles

Complete and persistent suppression of platelet thromboxane (TX) A(2) biosynthesis by aspirin is mandatory to fulfill its cardioprotection. We explored the determinants of heterogeneity of TXB2 generation in clotting whole blood, a capacity index of platelet cyclooxygenase (COX) activity, in patients with coronary heart disease (CHD) versus healthy subjects treated with low-dose aspirin on a long-term basis.. We studied 30 patients with CHD (ie, chronic stable angina, unstable angina, and acute myocardial infarction) and 10 healthy subjects, who were treated with low-dose aspirin (100 mg daily) on a long-term basis, 12 hours after the administration of 160 mg aspirin to ensure saturation of platelet COX-1 activity. Serum TXB2 levels were assessed. The contribution of blood COX-2 to TXA2 biosynthesis was explored by evaluation of the effect of a selective COX-2 inhibitor (L-745,337) added to heparinized whole blood stimulated with Ca++ ionophore A23187 (20 micromol/L) for 1 hour or lipopolysaccharide (0.1 microg/mL) for 4 hours.. In healthy subjects serum TXB2 levels ranged from 0.6 to 7.9 ng/mL (median, 2.1 ng/mL; mean +/- SD, 3.2 +/- 2.6 ng/mL). In CHD patients we detected enhanced variability in serum TXB2 generation (median, 3.1 ng/mL [range, 0.15-47 ng/mL]; mean, 8.5 +/- 12.3 ng/mL), which in 8 patients (27%) exceeded the mean value + 2 SDs detected in healthy subjects (ie, 8.4 ng/mL), set as the limit value for an adequate inhibition of platelet COX-1 by aspirin. Elevated whole-blood TXB2 generation was not dependent on leukocyte count, COX-2 activity, or cigarette smoking but was plausibly a result of defective suppression of platelet COX-1 activity.. Heterogeneity in the suppression of platelet COX-1 activity by aspirin occurred in CHD patients. The measurement of the serum TXB2 level seems to be an appropriate biomarker to identify patients who have an inadequate inhibition of platelet COX-1 activity by aspirin.

Topics: Aged; Arachidonic Acid; Aspirin; Blood Platelets; Calcimycin; Coronary Disease; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase Inhibitors; Female; Humans; Indans; Lipopolysaccharides; Male; Middle Aged; Neutrophils; Thromboxane A2; Thromboxane B2

Thirty patients with coronary artery disease (CAD) were administered garlic (study group) while another 30 patients received the placebo (control group). Various risk parameters were determined at 1.5 and 3 months of garlic administration. Garlic, administered in a daily dose of 2 x 2 capsules (each capsule containing ethyl acetate extract from 1 g peeled and crushed raw garlic), reduced significantly total serum cholesterol and triglycerides, and increased significantly HDL-cholesterol and fibrinolytic activity. There was no effect on the fibrinogen and glucose levels. In vitro effects of the garlic oil on platelet aggregation (PAg) and eicosanoid metabolism were examined; it inhibited PAg induced by several platelet agonists, and also platelet thromboxane formation. Two important paraffinic polysulphides - diallyl disulphide (DADS) and diallyl trisulphide (DATS) - derived from garlic and are usual constituents of garlic oil, showed antiplatelet activity, and also inhibited platelet thromboxane formation. In this respect DATS was more potent than DADS. The nature of inhibition of PAg by DATS was found to be reversible.

Topics: Allyl Compounds; Antihypertensive Agents; Arachidonic Acid; Blood Glucose; Calcimycin; Cholesterol; Cholesterol, HDL; Collagen; Coronary Disease; Disulfides; Dose-Response Relationship, Drug; Fibrinogen; Fibrinolysis; Garlic; Humans; Ionophores; Lipids; Plant Extracts; Plant Oils; Plants, Medicinal; Platelet Aggregation; Platelet Aggregation Inhibitors; Sulfides; Thromboxane B2; Triglycerides

Endostatin (EST) was found to initiate a redox signaling cascade associated with activation of NADPH oxidase in endothelial cells (ECs). The present study tested whether EST stimulates clustering of ceramide-enriched lipid rafts (LRs), which assembles and activates NADPH oxidase to form redox signaling platforms.. Using confocal microscopy, we first demonstrated a colocalization of LR clusters with NADPH oxidase subunits, gp91(phox) and p47(phox) in the ECs membrane on EST stimulation. Immunoblot analysis of floated detergent-resistant membrane fractions found that in LR fractions NADPH oxidase subunits gp91(phox) and p47(phox) are enriched and that the activity of this enzyme increased dramatically, as measured by electron spin resonance (ESR) spectrometry. This EST-increased LR platform formation was shown to be attenuated by inhibition or RNA interference of acid sphingomyelinase (A-SMase). Functionally, EST pretreatment significantly impaired bradykinin or A23187-induced vasodilation in isolated small coronary arteries, which could be partially reversed by LR disruptors.. The early injury effect of EST on the vascular endothelium is associated with the formation of redox signaling platforms via lipid raft clustering.

Topics: Analysis of Variance; Animals; Bradykinin; Calcimycin; Cattle; Cells, Cultured; Ceramides; Cluster Analysis; Coronary Disease; Coronary Vessels; Dilatation, Pathologic; Endostatins; Endothelial Cells; Membrane Microdomains; Microscopy, Confocal; NADPH Oxidases; Oxidation-Reduction; Probability; RNA; Signal Transduction

Direct gene transfer of exogenous nitric oxide synthase, with the subsequent increase in nitric oxide production, could represent a potential therapeutic strategy in the treatment of vascular proliferative disorders. The goal of the present study was to determine if porcine coronary arteries could be transduced with an adenoviral vector encoding endothelial nitric oxide synthase (Ad.CMVeNOS) resulting in functional expression.. Segments of porcine right coronary artery were exposed for 1 h at 37 degrees C to either replication-deficient adenovirus encoding bovine endothelial nitric oxide synthase (Ad.CMVeNOS, 5 x 10(9) pfu/ml) or control adenovirus encoding Escherichia coli beta-galactosidase (Ad.CMVLacZ, 5 x 10(9) pfu/ml). Immunohistochemistry with a monoclonal antibody specific for nitric oxide synthase (NOS) demonstrated recombinant gene expression in both the endothelial and adventitial layers of Ad.CMVeNOS transduced coronaries with only endogenous NOS confirmed in the endothelium of Ad.CMVLacZ arteries. Coronary arteries transduced with Ad.CMVeNOS yielded 517 +/- 110 (mean +/- S.E.M.) nM/ng nitrite while vessels transduced with Ad.CMVLacZ yielded 126 +/- 84 nM/ng (P < 0.05, n = 6). Isometric tension recording, following prostaglandin F2 alpha constriction, documented a reduced tension in Ad.CMVeNOS transduced coronaries, compared to matched Ad.CMVLacZ coronaries (6.10 +/- 1.08 g vs. 8.45 +/- 1.19 g, respectively, P = 0.05, n = 8). This tension differential was eliminated with prior incubation in NG-monomethyl-L-arginine (L-NMMA, 10(-4) M). The EC50 for calcium ionophore relaxation of Ad.CMVeNOS coronary arteries was reduced compared to Ad.CMVLacZ (-7.90 +/- 0.03 logM vs. -7.26 +/- 0.11 logM, respectively, P < 0.05, n = 8).. These studies demonstrate successful transfer of endothelial nitric oxide synthase into porcine coronary arteries as verified by histochemical localization of recombinant protein with an increase of nitric oxide release as demonstrated by enhanced nitrite production and an alteration in vasomotor function.

Topics: Adenoviridae; Analysis of Variance; Animals; Calcimycin; Coronary Disease; Coronary Vessels; Endothelium, Vascular; Gene Expression; Gene Transfer Techniques; Genetic Therapy; Genetic Vectors; Immunohistochemistry; Ionophores; Nitric Oxide Synthase; Nitrites; omega-N-Methylarginine; Swine; Vasoconstriction

Garlic's value in preventing cardiovascular disease has been reported by several research groups. Garlic and its components are known to possess antiplatelet activity which has been demonstrated mostly in vitro. It was found that garlic oil administration to healthy subjects and patients with coronary artery disease (CAD) inhibited platelet aggregation ex vivo. Though garlic components leave the body quickly, a slow build-up of the active ingredients may take place. This was evident from the observation that though a 2-3 fold higher dose was not effective in inhibiting platelet aggregation when administered once, a lower dose became effective in long-term administration.

Topics: Adult; Allyl Compounds; Calcimycin; Coronary Disease; Dose-Response Relationship, Drug; Drug Administration Schedule; Eicosanoids; Humans; Ionophores; Male; Middle Aged; Platelet Aggregation; Platelet Aggregation Inhibitors; Sulfides

The objective of this investigation was to determine the effect of cultured human umbilical vein endothelial cells (HUVEC) on the vascular response to canine coronary arteries in which the endothelium had been either mechanically removed or injured by multiple brief episodes of occlusion and reperfusion in vivo. The endothelium-dependent vasodilator, A23187 (10(-6) mol/l) did not cause any significant relaxation in vessels from which the endothelium had been removed. However, following addition of cultured HUVEC to the tissue bath (75 x 10(3) cells/ml), A23187 produced a significant (p < 0.05) relaxation. This effect was abolished by inhibition of nitric oxide synthase with Nw-nitro-l-arginine methyl ester (L-NAME). Vascular relaxation caused by the nitric oxide donor SIN-1 was significantly (p < 0.05) enhanced when cultured HUVEC were added to vessels mechanically denuded of endothelium. Repetitive ischemia and reperfusion significantly inhibited the relaxant response to A23187. Addition of cultured HUVEC to the tissue bath partially restored the response to A23187. In contrast to the mechanically damaged vessels the relaxant response to SIN-1 was unaffected by cultured HUVEC in reperfusion-injured vessels. These results demonstrate that cultured endothelial cells partially restore endothelium-dependent vasodilation of vessels in which the endothelium is not functional following mechanical- or reperfusion-induced damage. The differential effect of endothelial cells on the response to SIN-1 suggests that mechanical and reperfusion injury alter the coronary vascular response to SIN-1 by different mechanisms.

Topics: Animals; Arginine; Blood Flow Velocity; Calcimycin; Cells, Cultured; Coronary Circulation; Coronary Disease; Coronary Vessels; Dogs; Dose-Response Relationship, Drug; Endothelium, Vascular; Molsidomine; Muscle Relaxation; Muscle, Smooth, Vascular; Myocardial Contraction; Myocardial Reperfusion Injury; NG-Nitroarginine Methyl Ester; Nitric Oxide; Umbilical Veins; Vasodilator Agents

The aim was to establish whether the duration of coronary ischaemia and coronary ischaemia with reperfusion selectively reduced the magnitude of relaxation mediated by endothelium dependent relaxing factor (EDRF) in response to thrombin, compared with relaxation produced by acetylcholine and calcimycin.. Adult male dogs, anaesthetised with sodium pentobarbitone (30 mg.kg-1 intravenously) were used. Coronary artery occlusions were maintained for either 15 or 45 min; in half the dogs from each timepoint, occlusion was followed by 60 min reperfusion. At the end of each in situ period, coronary arteries were removed from both ischaemic and non-ischaemic regions, cut into rings, and hung in isolated organ baths. Dose-response relationships to the EDRF dependent vasodilators thrombin, acetylcholine, and calcimycin, and to the EDRF independent vasodilator isoprenaline, were then established.. Thrombin (0.003-0.3 units.ml-1) caused dose dependent relaxation in all tissues. Relaxant responses (E(max)) in the non-ischaemic vessels from both 15 and 45 min treatment groups were used as control data for the responses in ischaemic vessels. Maximum responses were not different in the non-ischaemic groups from either 15 or 45 min studies, at 82.7 (SEM 3.7)% after 15 min, and 82.1(2.4)% after 45 min. There was a small but significant reduction in E(max) after 15 min and 45 min ischaemia, to 74.4(3.2)% and 74.4(3.0)% respectively. Sixty minutes reperfusion provoked a further reduction in E(max) to 64.9(3.8)% after 45 min ischaemia, but not after 15 min ischaemia [70.3(4.2)%]. Neither 15 nor 45 min interventions altered E(max) of relaxation to acetylcholine or calcimycin (greater than 88.0% in each group). Similarly there were no significant differences between groups to the relaxation stimulated by isoprenaline (E(max) greater than 90.0%).. The data suggest that loss of EDRF dependent relaxation to thrombin is more sensitive to ischaemia than the relaxation produced by either acetylcholine or calcimycin, and appears to be manifested early in the onset of ischaemic injury.

Topics: Acetylcholine; Animals; Calcimycin; Coronary Disease; Coronary Vessels; Culture Techniques; Disease Models, Animal; Dogs; Dose-Response Relationship, Drug; Myocardial Contraction; Myocardial Reperfusion; Nitric Oxide; Thrombin; Time Factors

1 We studied the effects of a form of interleukin-8 (i.e., [Ala-IL8]77) on endothelial dysfunction and myocardial injury in rabbits. Pentobarbitone-anaesthetized rabbits were subjected to 1.5 h occlusion of the marginal coronary artery and 3.5 h reperfusion. [Ala-IL8]77 (50 micrograms or its vehicle) was given i.v. as a bolus 10 min prior to reperfusion. [Ala-IL8]77 was also studied in isolated perfused hearts of rabbits. 2 Myocardial ischaemia plus reperfusion in untreated rabbits produced severe endothelial dysfunction and myocardial injury, including marked myocardial necrosis, elevated cardiac myeloperoxidase (MPO) activity in ischaemic cardiac tissue, and loss of response of marginal coronary rings to the endothelium-dependent vasodilators, acetylcholine (ACh) and A23187. 3 Administration of [Ala-IL8]77 10 min prior to reperfusion resulted in significant protective effects in post-ischaemic reperfusion. Compared with untreated rabbits, [Ala-IL8]77 caused a reduced necrotic zone (P less than 0.01), lower MPO activity in the necrotic zone (P less than 0.05), and significantly preserved vasorelaxant responses of marginal coronary artery rings to endothelium-dependent vasodilators, ACh (P less than 0.001) and A23187 (P less than 0.001). 4 These results indicate that myocardial ischaemia and reperfusion result in a severe endothelial dysfunction and myocardial injury which involved the interaction of neutrophils and endothelial cells. However, [Ala-IL8]77 did not appear to exert a direct endothelial protective effect in the absence of neutrophils in rabbit isolated perfused hearts. 5 Inhibition of neutrophil accumulation in the myocardium, perhaps by prevention of endothelial dysfunction resulting from [Ala-IL8]77, leads to significant protective effects in ischaemia and reperfusion in rabbits.

Topics: Acetylcholine; Animals; Blood Pressure; Calcimycin; Coronary Disease; Endothelium, Vascular; Heart Diseases; Heart Rate; In Vitro Techniques; Interleukin-8; Male; Myocardial Reperfusion Injury; Myocardium; Neutrophils; Nitric Oxide; Peroxidase; Rabbits; Superoxides

The time course of the effects of permanent myocardial ischemia without reperfusion on the coronary vascular endothelium and myocardium were investigated in anesthetized cats. The left anterior descending (LAD) coronary artery was occluded for 1.5, 3.0, 4.5, or 6.0 h. Coronary rings from the ischemic LAD and the nonischemic left circumflex (LCX) arteries were tested for their responsiveness to the endothelium-dependent vasodilators acetylcholine (ACh, 0.1-100 nM) and the calcium ionophore A23187 (1-1,000 nM), and the endothelium-independent vasodilator sodium nitrite (NaNO2, 0.1-100 microM). Vasorelaxation was not significantly impaired in response to ACh after 1.5 h of ischemia and only moderately impaired after 3.0 h of ischemia (63 +/- 5% of control). However, after 4.5 h of ischemia the ACh-induced response was decreased to 33 +/- 4% of control and further declined to 31 +/- 4% of control after 6.0 h (P less than 0.001 from 1.5 h). There was no significant decrease in LCX ring vasorelaxant responses to vasodilators at all times, and the LAD rings only showed a moderately decreased response to NaNO2 after 6.0 h of ischemia (82 +/- 4% relaxation, P less than 0.05). Transmission electron microscopy revealed very little endothelial damage at 4.5 and 6.0 h, with only some subendothelial swelling noted. Damage to the myocardium did not become significant until after 4.5 h of ischemia, and cardiac myeloperoxidase activity, indicative of neutrophil accumulation, was not significant at any time.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Acetylcholine; Animals; Arterial Occlusive Diseases; Calcimycin; Cats; Coronary Disease; Coronary Vessels; Creatine Kinase; Dose-Response Relationship, Drug; Endothelium, Vascular; In Vitro Techniques; Male; Microscopy, Electron; Muscle, Smooth, Vascular; Myocardium; Peroxidase; Sodium Nitrite; Vasodilation

This study investigates biochemical and functional interactions between NO and PGI2 that generate pathways in two different in vitro assays: porcine aortic endothelial cells (PAEC) and reperfused ischemic Langendorff hearts of rabbits. Using cGMP as an index of NO generation and 6-oxo-PGF1 alpha as an index for PGI2 production in endothelial cells, it is demonstrated that the two metabolic pathways for NO and prostacyclin formation act independent of each other. Moreover, NO appears to have an autocrine function in endothelial cells which does not exist with PGI2, probably because of a lack of PGI2 receptors. Endothelial damage in the course of myocardial ischemia is associated with a marked increase in mediator release whose inhibition has consequences for both myocardial and coronary function: inhibition of NO formation also inhibits PGI2 release and the recovery of coronary vessel tone with only minor if any effect on myocardial contractility. In contrast, inhibition of PGI2-generation results in marked deterioration of myocardial recovery with only minor changes in coronary perfusion. It is concluded from these data that PGI2 in endothelial injury is important for preservation of myocardial function while NO might mainly be involved in control of local vessel tone.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Calcimycin; Cells, Cultured; Coronary Disease; Cyclic AMP; Cyclic GMP; Endothelium, Vascular; Epoprostenol; Heart; Myocardial Reperfusion; Nitric Oxide; Rabbits; Swine

Myocardial ischemia inhibits endothelium-dependent relaxation stimulated by the coagulant peptide, thrombin. To investigate whether activation of endogenous thrombin contributed to this reduction in relaxant sensitivity, the effects of pretreatment of dogs with the coumarin anticoagulant, brodifacoum, were studied. Experiments were performed in both normal coronary vasculature and coronary vasculature exposed to 90 min of myocardial ischemia, with or without 60 min of subsequent reperfusion. Ischemia was induced in the left anterior descending artery (LAD); nonischemic vessels from the left circumflex (LCX) artery of the same animals were used as control. Thrombin caused dose-dependent relaxation in isolated LCX preconstricted with prostaglandin F2 alpha (Emax of 89.1 +/- 2.33%). Relaxation was reduced by 90 min of ischemia (Emax of 27.5 +/- 8.0%; p less than 0.05), and further reduced after subsequent reperfusion (Emax of 8.7 +/- 8.7%). However, maximum relaxations to acetylcholine, calcimycin, and isoproterenol were unchanged after ischemia (Emax greater than 90% in all groups). Brodifacoum had no effect on thrombin-induced relaxation in control vessels (Emax of 83.0 +/- 3.5%), or on relaxation in response to acetylcholine, calcimycin, or isoproterenol (Emax greater than 90%). In contrast, brodifacoum markedly reduced thrombin-induced relaxation after ischemia (Emax of 3.3 +/- 3.3%; p less than 0.05) yet significantly preserved the relaxant response to thrombin after ischemia and reperfusion (Emax of 36.6 +/- 4.3%). Infusion of the thrombin inhibitor, D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone (PPACK), during ischemia and reperfusion also preserved in part the relaxant response induced by thrombin (Emax of 30.0 +/- 5.1%; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: 4-Hydroxycoumarins; Acetylcholine; Amino Acid Chloromethyl Ketones; Animals; Blood Coagulation; Calcimycin; Coronary Disease; Dinoprost; Dogs; Endothelium, Vascular; In Vitro Techniques; Isoproterenol; Male; Muscle Relaxation; Nitric Oxide; Thrombin

Leukotriene C4 is a potent constrictor of smooth muscle in vitro and may induce coronary vasoconstriction in vivo. To study leukotriene C4 release by neutrophils in patients with coronary artery disease, neutrophils were separated from blood samples taken from the coronary sinus and aorta in 20 patients with stable exertional angina and angiographically documented coronary artery narrowings (group I). Eight patients with normal coronary arteries were also studied (group II). To assess leukotriene C4 generation, neutrophils were incubated with calcium ionophore A 23187 (0.25 microM) and the supernatants obtained after centrifugation were analyzed for leukotriene C4 by radioimmunoassay. Patients in group I had a significantly lower release of leukotriene C4 from neutrophils separated from the coronary sinus blood than from those separated from aortic blood (4.33 +/- 0.69 versus 5.92 +/- 0.54 ng/ml, p less than 0.025), whereas patients in group II had a similar release of leukotriene C4 by the neutrophils separated from coronary sinus blood and from aortic blood (6.0 +/- 0.72 versus 6.4 +/- 0.66 ng/ml, p = NS). Moreover, in group I patients, a significant correlation was found (p less than 0.01) between the extent of coronary artery disease (expressed by the Leaman coronary score) and the percent reduction in leukotriene C4 released from neutrophils separated from coronary sinus blood as compared with leukotriene C4 produced by neutrophils separated from aortic blood. These data show that neutrophils from patients with coronary artery disease have a reduced ability to produce leukotriene C4 after stimulation by calcium ionophore A 23187.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Aorta; Calcimycin; Coronary Angiography; Coronary Disease; Female; Humans; Leukocyte Count; Male; Middle Aged; Neutrophils; Radioimmunoassay; SRS-A; Stroke Volume; Vasoconstriction

Previous in vivo studies have shown that vasopressin, which releases the endothelium-derived relaxing factor and constricts coronary smooth muscle, produces augmented constriction of coronary microvessels perfused by mature collaterals. We hypothesized that chronic perfusion through collaterals produces endothelial dysfunction in the recipient vasculature. Mature collaterals were stimulated in mongrel dogs by the ameroid constrictor technique. After 3-6 months, rings of conduit vessels (obtuse marginals) were studied in organ chambers, and coronary microvessels (100-220 microns) were studied in a pressurized, no-flow state with a microvessel imaging apparatus. Eleven dogs were used as controls. Large vessels were preconstricted with prostaglandin F2 alpha to 30-70% of the maximum potassium chloride tension, and microvessels were preconstricted to 20-60% of the baseline diameter with the thromboxane mimetic U46619. Relaxations to the receptor-mediated agents acetylcholine and ADP were markedly impaired in collateral-dependent coronary microvessels, whereas relaxations to nitroglycerin were enhanced compared with microvessels from control dogs. Relaxation to the calcium ionophore A23187, which releases the endothelium-derived relaxing factor through nonreceptor-mediated mechanisms, were similar in control and ameroid microvessels. Constriction to vasopressin was augmented in collateral-dependent microvessels compared with controls. Responses to all agonists were similar between control and collateral-dependent large vascular rings. In conclusion, chronic perfusion through collateral vessels selectively impairs receptor-mediated endothelium-dependent relaxations and augments constriction to vasopressin in the coronary microcirculation. These findings may have important implications regarding neurohumoral regulation of perfusion to collateral-dependent myocardium.

Topics: Acetylcholine; Adenosine Diphosphate; Animals; Calcimycin; Collateral Circulation; Coronary Circulation; Coronary Disease; Dogs; Endothelium, Vascular; Female; In Vitro Techniques; Male; Nitroglycerin; Potassium Chloride; Vasoconstriction; Vasopressins

Circulating granulocytes play an important role in microvascular perfusion and organ pathology. Oxygen radicals released by aggregated and activated neutrophils may exacerbate the tissue damage caused by ischemia. We studied neutrophil aggregation and oxygen metabolites release in 16 patients suffering from coronary artery disease and in 6 control subjects in aorta and coronary sinus blood samples. The neutrophil aggregation (P less than 0.01) and oxidase activity (P less than 0.01) are higher in coronary sinus than aorta samples only in the patients with respect to controls. While the superoxide generation is decreased in coronary sinus (P less than 0.05). Our aggregation assay supported the potential role of granulocytes in neutrophil-endothelial interactions and tissue damage, and our results about oxidase activity and superoxide release suggested the potential role for neutrophil-derived oxygen radicals in the pathogenesis of vascular injury in vivo.

Topics: Calcimycin; Cell Aggregation; Coronary Disease; Granulocytes; Humans; Oxidation-Reduction; Superoxides

In the present studies, we demonstrate in buffer-perfused isolated working guinea pig hearts that indometacin reduces coronary flow rate in a dose-dependent manner (max 56.7 +/- 5.5%, SEM, n = 6, of control at 5 x 10(-6) mol/l of indometacin, P less than 0.01), and that this leads to a development of heterogeneous patterns of myocardial ischemia (elevated myocardial levels of reduced pyridine nucleotide, NADH) and depressed cardiac work (64.7 +/- 11.7%, SEM, of control at 5 x 10(-6) mol/l of indometacin, P less than 0.05). The effect of indometacin on coronary flow rate and consequently on myocardial tissue oxygenation was completely prevented by the preferential 5-lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA) (1 x 10(-6) mol/l), or the sulfidopeptide leukotriene receptor antagonist FPL 55712 (2 x 10(-5) mol/l), indicating that the isolated working guinea pig heart, even when deprived of blood, is able to produce vasoactive sulfidopeptide leukotrienes at significant levels. At higher concentrations of indometacin (5 x 10(-5) mol/l, 1 x 10(-4) mol/l), coronary flow rate returned to initial levels while cardiac work became further depressed despite normoxic levels of NADH. These data support that indometacin also has a direct suppressive effect on the myocardium independent of its coronary vascular effect. This conclusion is supported by the observation that addition of sodium arachidonate (6 x 10(-5) mol/l) completely inhibited the vascular effect of indometacin, but not the depressive effect on the myocardium. The divalent cation ionophore A23187 (6 x 10(-6) mol/l) had a strong positive chronotropic effect on the heart and a biphasic effect on coronary flow rate. After a brief period of increased coronary flow rate, presumably due to coronary vasodilatation, the ionophore caused a sustained reduction in coronary flow, and this was accompanied by high myocardial levels of NADH fluorescence of characteristically heterogeneous pattern. This is presumably caused by vasoconstrictory effects of elevated levels of intracellular Ca2+ of vascular smooth muscle, independent of stimulation of 5-lipoxygenase or cyclooxygenase pathways, since neither indometacin nor nordihydroguaiaretic acid modified the effect of A23187.

Topics: Animals; Arachidonate Lipoxygenases; Calcimycin; Coronary Circulation; Coronary Disease; Cyclooxygenase Inhibitors; Guinea Pigs; Indomethacin; Lipoxygenase Inhibitors; Male; Masoprocol; Myocardial Contraction

In dogs undergoing 24- or 72-hr severe narrowing of the left anterior descending coronary artery (LAD), the in vitro formation of immunoreactive leukotriene C4 (LTC4) by the stenosed LAD was greatly augmented by 1 microM A23187 in a 10-min incubation at 37 degrees. This stimulated LTC4 formation was abolished by 30 microM nordihydroguaiaretic acid (NDGA). The incubation products were identified by high performance liquid chromatography and radioimmunoassay to be largely composed of LTC4 and LTD4 in similar proportion. In contrast to the stenosed LAD, the non-stenotic left circumflex coronary artery, apex of the heart, and renal artery of the same experimental animals failed to respond to the calcium ionophore up to 10 microM. The vascular and cardiac tissues from sham-operated animals also remained quiescent in the presence of A23187. The normal coronary artery showed low levels of leukotriene formation and was resistant to the ionophore. It is proposed that a latent portion of leukotriene synthesis, which can be triggered by the calcium ionophore, may play a significant role in the pathogenesis of coronary artery spasm associated with acute myocardial infarction and angina pectoris in patients with obstructive coronary artery disease.

Topics: Animals; Calcimycin; Chromatography, High Pressure Liquid; Coronary Disease; Coronary Vessels; Dogs; Electrocardiography; Female; Male; Masoprocol; SRS-A; Time Factors

Topics: Animals; Arginine Vasopressin; Calcimycin; Coronary Disease; Diabetes Mellitus, Experimental; Lung; Rats; SRS-A

It has been proposed that breakdown of the excitation-contraction coupling system plays a pivotal role in myocardial dysfunction during the course of acute ischemia. We tested this hypothesis by characterizing the function of the sarcoplasmic reticulum at pH 7.1 and 6.4 after 7.5, 15, and 30 minutes of canine normothermic global ischemia. At pH 7.1, whole heart homogenate sarcoplasmic reticulum demonstrated a 49% depression of oxalate-supported calcium uptake at 7.5 minutes of ischemia, which progressed to 85% at 30 minutes of ischemia. At pH 6.4, control homogenate calcium uptake rates were significantly depressed, accompanied by a further depression in the ischemic groups. Isolated sarcoplasmic reticulum calcium uptake mirrored the effects of the whole heart homogenate. Calcium-stimulated magnesium-dependent ATPase (calcium-ATPase) activity was significantly depressed by both ischemia and acidosis, with a decrease in the coupling ratio (mumol calcium/mumol ATP) at 15 and 30 minutes of ischemia. Acidosis (pH 6.4) significantly shifted the sarcoplasmic reticulum pCalcium-ATPase curve to the right, increasing 50% activation from pCalcium 6.0 to 5.5 and depressing the maximum velocity (pH 7.1 = 2.06 +/- 0.14; pH 6.4 = 1.41 +/- 0.05 mumol Pi/mg per min; P less than 0.01). With ischemia, there was a progressive decrease in maximal activation of the calcium-ATPase enzyme and a progressive shift in calcium sensitivity to a higher concentration. Steady state calcium uptake, in the absence of oxalate, demonstrated a similar depression after 7.5 and 15 minutes of ischemia at pH 7.1 and 6.4, associated with a significant increase in the passive permeability coefficient for calcium.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adenosine Triphosphate; Animals; Biological Transport; Ca(2+) Mg(2+)-ATPase; Calcimycin; Calcium; Calcium-Transporting ATPases; Coronary Disease; Dogs; Female; Heart; Hydrogen-Ion Concentration; Hydrolysis; Male; Sarcoplasmic Reticulum; Time Factors

[Ca2+]i was raised experimentally in mammalian and amphibian skeletal and cardiac muscles by A23187, DNP, anoxia or the Ca2+ -paradox. Trifluoperazine (TFP) at 10(-5) M failed to protect against the characteristic and rapid damage triggered by elevated [Ca2+]i in any of the preparations. It is concluded that calmodulin is not implicated in this rapid ultrastructural damage. TFP alone also causes identical patterns of damage. It may be acting to raise [Ca2+]i in skeletal and cardiac muscle cells.

Topics: Animals; Calcimycin; Calcium; Coronary Disease; Dinitrophenols; Hypoxia; Mice; Muscular Diseases; Rana temporaria; Subcellular Fractions; Trifluoperazine

The effect of fatty acid and acylcarnitine on Ca2+ and Na+ transporting enzymes and carriers was studied in sealed cardiac sarcolemma vesicles of mixed polarity. Palmitoylcarnitine markedly reduced the Na+ gradient-induced Ca2+ uptake. Half-maximal reduction was obtained at 15 microM of the carnitine derivative. In a same concentration range palmitoylcarnitine caused a rapid release of accumulated Ca2+ when added to Ca2+-filled vesicles, which suggests that palmitoylcarnitine increases the permeability of the sarcolemma vesicles to Ca2+. A rapid release of Ca2+ was also observed if Ca2+ was taken up by action of the Ca2+ pump. The (Ca2+ + Mg2+)-ATPase, which most likely drives this active Ca2+ uptake, was 90% increased by 50 microM palmitoylcarnitine and evidence was presented that the acylcarnitine effect again was linked to an alteration of Ca2+ permeability of the vesicles. At the same concentration acylcarnitine was not able to unmask the latent protein kinase, so that probably the sarcolemma ATP permeability was not affected. Palmitoylcarnitine at 25 microM did not affect the ouabain-sensitive (Na+ + K+) -ATPase in native sarcolemma vesicles, however, it inhibited markedly if the enzyme was measured in SDS-treated vesicles. The effect of increased free fatty acid concentration on some of the sarcolemma transporting properties was tested by adding oleate-albumin complexes with different molar ratios to the sarcolemma vesicles. In contrast to molar ratios 1 and 5, the ratio of 7 was able to induce a rapid Ca2+ release and to inhibit (Na+ + K+)-ATPase in either native or SDS-treated vesicles markedly. 22Na release from 22Na-preloaded sarcolemma vesicles was shown to be stimulated by either palmitoylcarnitine (50 microM) or oleate-albumin complex (with a molar ratio of 7). The possible significance of the observed effects of lipid intermediates on ion permeability and (Na+ + K+)-ATPase activity in isolated sarcolemma vesicles for the derangement of cardiac cell function in ischemia is discussed.

Topics: Animals; Calcimycin; Calcium; Carnitine; Cell Membrane Permeability; Coronary Disease; Fatty Acids; Myocardium; Palmitoylcarnitine; Protein Kinases; Sarcolemma; Sodium; Sodium-Potassium-Exchanging ATPase; Swine

Regional myocardial function was measured with miniature ultrasonic crystals before, during, and after 10 min of coronary occlusion in anaesthetised open-chest dogs. In normal myocardium, intracoronary isoprenaline (0.1 micrograms . min-1) increased contraction velocity during the first third of systole (early systolic velocity) from 13.8 +/- 2.5 to 19.4 +/- 3.9 mm . s-1 . cm-1, (P < 0.01), and blood flow (microspheres) from 0.55 +/- 0.04 to 0.80 +/- 0.12 cm3 . min-1 . g-1 (P < 0.05); lactate extraction was unchanged. Coronary occlusion induced dyskinesia with a fall in early systolic velocity to -10.0 +/- 2.4 mm . s . -1 . cm-1 (P < 0.01). Abrupt reperfusion after 10 min of ischaemia permitted recovery towards normal, but regional function then deteriorated over 15 min. After a second infusion of isoprenaline, early systolic velocity increased from 0.8 +/- 2.2 to 14.2 +/- 2.5 mm . s-1 . cm-1 (P < 0.01), blood flow 0.44 +/- 0.03 to 0.73 +/- 0.14 cm3 . min-1 . g-1 (P < 0.01) and oxygen consumption 50 +/- 5 to 58 +/- 5 mm3 . min-1 . g-1 (P < 0.05). Lactate extraction was unchanged. In a further series of experiments, administration of nitroglycerin and methoxamine accelerated recovery from dyskinesia induced by coronary occlusion, but did not modify late deterioration during reperfusion. Similarly, neither propranolol nor hypertonic mannitol were found to modify reperfusion damage. Four agents which affect calcium ion movement were studied. Verapamil and isoprenaline, drugs which respectively diminish and enhance calcium slow current, had no effect on reperfusion damage. By contrast, ruthenium red, a non-specific calcium inhibitor reduced deterioration and calcium ionophore (A23187; Lilly) increased it. muDepressed function in reperfused myocardium is not the result of residual ischaemia per se, gut is consistent with calcium overload during the period of reperfusion.

Topics: Animals; Calcimycin; Coronary Circulation; Coronary Disease; Dogs; Heart; Isoproterenol; Lactates; Mannitol; Myocardial Contraction; Myocardium; Nitroglycerin; Oxygen Consumption; Propranolol; Ruthenium Red; Verapamil

Experimentally-induced rises in intracellular calcium ([Ca2+]i) promote rapid myofilament degradation in amphibian and mammalian cardiac muscle strips. The relevance of these studies to the subcellular injury produced by ischaemia, the possible involvement of lysosomal enzymes and similarities with skeletal muscle are discussed.

Topics: Animals; Calcimycin; Calcium; Coronary Disease; Dinitrophenols; Heart; In Vitro Techniques; Mice; Muscles; Myocardium; Rana temporaria