leukotriene-b4 and methyl-2-((3-4-dihydro-3-4-dioxo-1-naphthalenyl)amino)benzoate

We evaluated the effect of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 alpha (IL-1 alpha) on pig cardiopulmonary function by intravenously infusing each cytokine individually or in combination (0.5 microgram/kg from 0 to 0.5 h + 5 ng.kg-1 x min-1 from 0.5 to 6 h for each cytokine). The role of eicosanoids in mediating the TNF-alpha + IL-1 alpha-induced cardiopulmonary dysfunction was also investigated by pretreating cytokine-infused pigs with CGS 8515 (5-lipoxygenase inhibitor) or indomethacin (cyclooxygenase inhibitor). Coinfusion of TNF-alpha with IL-1 alpha caused additive increases (P < 0.05) in total peripheral resistance and plasma concentrations of 6-keto-prostaglandin F1 alpha (PGF1 alpha). The increases in mean pulmonary arterial pressure (Ppa), pulmonary vascular resistance (PVR), alveolar-arterial O2 gradient (AaDO2), alveolar dead space-to-tidal volume ratio (VD/VT), and plasma concentrations of thromboxane B2 were either additive or synergistic. CGS 8515 blocked the TNF-alpha + IL-1 alpha-induced increases (P < 0.05) in mean aortic pressure, total peripheral resistance (4-6 h), VD/VT (5-6 h), and, at 6 h, attenuated the increases in Ppa, PVR, and AaDO2. Indomethacin blocked or attenuated the cytokine-induced increases (P < 0.05) in Ppa, PVR, AaDO2, VD/VT, and plasma concentrations of thromboxane B2 and 6-keto-PGF1 alpha. The 1-to 2-h systemic hypotension, caused by TNF-alpha + IL-1 alpha, was not abrogated by either indomethacin or CGS 8515. The cytokines did not alter plasma concentrations of leukotriene B4 or 5-hydroxyeicosatetraenoic acid. We conclude that coinfusion of TNF-alpha with IL-1 alpha induces physiological responses that are additive or synergistic and that cyclooxygenase and 5-lipoxygenase products (other than leukotriene B4 and 5-hydroxyeicosatetraenoic acid) importantly mediate cardiopulmonary dysfunction in pigs infused with TNF-alpha + IL-1 alpha.

Topics: 6-Ketoprostaglandin F1 alpha; Albumins; Animals; Arachidonic Acids; Bronchoalveolar Lavage Fluid; Chromatography, High Pressure Liquid; Cyclooxygenase Inhibitors; Cytokines; Dinoprost; Drug Synergism; Eicosanoids; Heart; Heart Diseases; Hydroxyeicosatetraenoic Acids; Indomethacin; Injections, Intravenous; Interleukin-1; Leukotriene B4; Lipoxygenase Inhibitors; Lung; Lung Diseases; Naphthoquinones; ortho-Aminobenzoates; Swine; Thromboxane B2; Tumor Necrosis Factor-alpha; Vascular Resistance

We hypothesized that 5-lipoxygenase and cyclooxygenase products might be mediators of cardiopulmonary and systemic vascular effects induced by a 4 h continuous infusion of platelet-activating factor (PAF, 10 ng/kg/min) in anesthetized pigs. Indomethacin (cyclooxygenase inhibitor) potentiated and CGS 8515 (5-lipoxygenase inhibitor) attenuated PAF-induced increases in total peripheral resistance (TPR) from 2.5 to 4 h. However, the 5-lipoxygenase inhibitor failed to modify pulmonary vasoconstriction and hypertension caused by PAF. Except for a delay in onset (approximately 44 s) and rate of development of pulmonary hypertension during the initial 10 min of PAF infusion, the pulmonary hemodynamic changes were also not attenuated by indomethacin. On the other hand, at 4 h, the PAF-induced pulmonary hypertension and systemic vasoconstriction were completely or partially reversed, respectively, by WEB 2086 (PAF receptor antagonist). The PAF-induced increases in plasma thromboxane B2 (TXB2) were blocked by indomethacin but not by CGS 8515, and at 4 h the 5-lipoxygenase inhibitor potentiated the levels of TXB2 in pigs treated with PAF. The plasma concentrations of 6-keto-PGF1 alpha and leukotriene B4 (LTB4) were not modified by PAF or CGS 8515 + PAF. We conclude that PAF-induced increases in TPR (2.5-4 h) are potentiated by indomethacin and are dependent on 5-lipoxygenase products other than LTB4. Although the early pulmonary vascular response (< 10 min) to PAF is dependent on cyclooxygenase products, the sustained response (after 10 min) cannot be explained by either 5-lipoxygenase or cyclooxygenase products but may be mediated directly by PAF receptors.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Azepines; Blood; Calcimycin; Chromatography, High Pressure Liquid; Cyclooxygenase Inhibitors; Hemodynamics; Hypertension, Pulmonary; In Vitro Techniques; Indomethacin; Infusions, Intra-Arterial; Leukotriene B4; Lipoxygenase Inhibitors; Naphthoquinones; ortho-Aminobenzoates; Platelet Activating Factor; Swine; Thromboxane B2; Triazoles

Naphthoquinones are known to inhibit 5-lipoxygenase. In particular, CGS 8515 (methyl 2-[(3,4-dihydro-3,4-dioxo-1-naphthalenyl)amino]benzoate) has been studied in detail. However this potent and selective 5-lipoxygenase inhibitor has a short duration of action and poor bioavailability. To improve the duration of action we have prepared a series of carbon substituted naphthoquinones. Several members of this series have demonstrated potent in vitro inhibition of 5-LO (IC50's less than 10(-6) M) and at doses of 1 mg/kg iv completely inhibited LTB4 production measured in ex vivo A23187-stimulated blood from dogs. The duration of action measured by the ex vivo assay was improved up to threefold over CGS 8515.

Topics: Animals; Biological Availability; Calcimycin; Dogs; Female; Guinea Pigs; Half-Life; In Vitro Techniques; Leukotriene B4; Lipoxygenase Inhibitors; Male; N-Formylmethionine Leucyl-Phenylalanine; Naphthoquinones; ortho-Aminobenzoates; Radioimmunoassay

CGS 8515 inhibited 5-hydroxyeicosatetraenoic acid (5-HETE) and leukotriene B4 synthesis in guinea pig leukocytes (IC50 = 0.1 microM). The compound did not appreciably affect cyclooxygenase (sheep seminal vesicles), 12-lipoxygenase (human platelets), 15-lipoxygenase (human leukocytes) and thromboxane synthetase (human platelets) at concentrations up to 100 microM. CGS 8515 inhibited A23187-induced formation of leukotriene products in whole blood (IC50 values of 0.8 and 4 microM, respectively, for human and rat) and in isolated rat lung (IC50 less than 1 microM) in vitro. The selectivity of the compound as a 5-lipoxygenase inhibitor was confirmed in rat whole blood by the 20-70-fold separation of inhibitory effects on the formation of leukotriene from prostaglandin products. Ex vivo and in vivo studies with rats showed that CGS 8515, at an oral dose of 2-50 mg/kg, significantly inhibited A23187-induced production of leukotrienes in whole blood and in the lung. The effect persisted for at least 6 h in the ex vivo whole blood model. CGS 8515, at oral doses as low as 5 mg/kg, significantly suppressed exudate volume and leukocyte migration in the carrageenan-induced pleurisy and sponge models in the rat. Inhibitory effects of the compound on inflammatory responses and leukotriene production in leukocytes and target organs are important parameters suggestive of its therapeutic potential in asthma, psoriasis and inflammatory conditions.

Topics: Animals; Arachidonate Lipoxygenases; Arachidonic Acid; Arachidonic Acids; Benzoquinones; Biotransformation; Blood Platelets; Calcimycin; Dexamethasone; Guinea Pigs; Humans; Hydroxyeicosatetraenoic Acids; Indomethacin; Leukocytes; Leukotriene B4; Lipoxygenase Inhibitors; Male; Naphthoquinones; ortho-Aminobenzoates; Pleurisy; Quinones; Rats; Rats, Inbred Strains; Sheep