5-hydroxy-6-8-11-14-eicosatetraenoic-acid and azelastine

We investigated the effects of azelastine, an anti-allergic agent, on the release of arachidonic acid metabolites from cultured human umbilical vein endothelial cells (HUVEC). High performance liquid chromatography (HPLC) revealed that HUVEC treated with 10(-5) M azelastine released smaller amounts of arachidonic acid metabolites into the medium than control HUVEC. Azelastine significantly reduced the release of prostaglandin F2 alpha (PGF2 alpha), leukotriene B4 (LTB4) and 5-hydroxy-eicosatetraenoic acid (5-HETE) by HUVEC. These results suggest that azelastine may inhibit contraction of bronchial smooth muscle cells and reduce bronchial inflammation by suppressing the release of arachidonic acid metabolites from vascular endothelial cells.

Topics: Anti-Allergic Agents; Arachidonic Acid; Bronchoconstriction; Cells, Cultured; Chromatography, High Pressure Liquid; Dinoprost; Endothelium, Vascular; Humans; Hydroxyeicosatetraenoic Acids; Leukotriene B4; Muscle Contraction; Phthalazines; Umbilical Veins

Azelastine produced a concentration-dependent inhibition of calcium ionophore A23187 (0.2 microM) stimulated generation of 5-HETE, leukotriene B4, and leukotriene C4 in rat mixed peritoneal cells, yielding IC50 values of 35.5, 47.4, and 31.7 microM, respectively. Nordihydroguaiaretic acid (a potent 5-lipoxygenase inhibitor) also exerted a strong and concentration-dependent inhibition of 5-HETE and leukotriene B4 and C4 formation with IC50 values of 0.15, 0.09, and 0.1 microM, respectively. The inhibition of the formation of the products of the lipoxygenase pathway of arachidonic acid metabolism by azelastine may contribute to its overall antiallergic, antiasthmatic, and pulmonary anti-inflammatory activities.

Topics: Animals; Calcimycin; Depression, Chemical; Histamine H1 Antagonists; Hydroxyeicosatetraenoic Acids; Leukotriene B4; Peritoneal Cavity; Phthalazines; Radioimmunoassay; Rats; SRS-A

Azelastine, a newly synthesized antiallergic agent, strikingly inhibited the production of leukotriene B4 and C4 (LTB4 and LTC4) in murine peritoneal cells which had been stimulated by calcium ionophore A23187. The 50% inhibitory concentrations (IC50) of the agent were approximately 1.0 x 10(-5) M. In addition, azelastine significantly inhibited also 5-lipoxygenase activity in peritoneal cells with an IC50 of 1.0 x 10(-5) M, but not on LTC4 synthetase, LTA4 hydrolase or phospholipase A2 activity. Furthermore, azelastine showed little effect on either 12-lipoxygenase activity or thromboxane synthesis in human platelets. These results suggest that at least the drug's antiallergic effects can be attributed to its inhibiting action of 5-lipoxygenase in regard to arachidonate metabolism.

Topics: Animals; Blood Platelets; Calcimycin; Dose-Response Relationship, Drug; Epoxide Hydrolases; Glutathione Transferase; Hydroxyeicosatetraenoic Acids; Ketotifen; Leukotrienes; Lipoxygenase; Mice; ortho-Aminobenzoates; Peritoneal Cavity; Phospholipases A; Phospholipases A2; Phthalazines; Piperazines; Pyridazines; Thromboxanes

The dissolution of infarcted myocardium occurs after the infiltration of leukocytes. In the search for a mechanism of the leukocyte infiltration, we measured the production of lipoxygenase metabolites of arachidonic acid in the canine myocardium after ligation of the circumflex branch of the left coronary artery. At least 2 lipoxygenase products, namely 5- and 12-hydroxyeicosatetraenoic acids (HETEs), were augmented in myocardium subjected to ischemia lasting more than 6 hours, with levels of the latter being raised much more than the former. Augmentation of the HETEs in ischemic myocardium appeared to occur prior to any significant infiltration of leukocytes. More than 12 hours after coronary ligation, the infiltration of leukocytes became prominent and an increase in 12-HETE was observed. Calcium content in the infarcted myocardium appeared to be increased several hours before the increase in 12-HETE. These data suggest that the initial increment in 12-HETE may result from it being a product of infarcted myocardium, where Ca2+ is accumulated in the cell, and that the increased HETEs work as a leukocyte chemoattractant in infarcted myocardium. This hypothesis is supported by the independent experiment which showed that cultured cardiomyocytes produced lipoxygenase metabolites of arachidonic acid, including 12-HETEs etc, which exhibited neutrophil-chemoattractant activity when they were challenged by calcium ionophore and/or arachidonic acid. Azelastine-HCl, a lipoxygenase inhibitor, attenuated not only the above production of HETEs from the cardiomyocytes, but also production of HETEs and infiltration of neutrophils in ischemic myocardium, resulting in attenuation of the fibrous scar of infarcted myocardium.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Animals; Calcium; Chemotaxis, Leukocyte; Coronary Disease; Dogs; Hydroxyeicosatetraenoic Acids; Leukocytes; Lipoxygenase Inhibitors; Myocardium; Phthalazines