prostaglandin-d2 and enofelast

The action of 5-lipoxygenase on arachidonic acid generates potent inflammatory mediators that may contribute to the pathophysiology of asthma.. Using the potent and selective 5-lipoxygenase inhibitor BI-L-239, we have examined the role of 5-lipoxygenase products in three animal models of asthma.. In vitro BI-L-239 inhibited 5-lipoxygenase product generation from human lung mast cells, alveolar macrophages, and peripheral blood leukocytes with a concentration that would provide 50% inhibition values of 28 to 340 nmol/L. A 36-fold selectivity for immunoreactive leukotriene C4 versus immunoreactive prostaglandin D2 inhibition was demonstrated in mast cells. In anesthetized cynomolgus monkeys, inhaled BI-L-239 provided dose-dependent inhibition of the inhaled Ascaris-induced immunoreactive leukotriene C4 release (maximum, 73%; bronchoalveolar lavage [BAL], 20 minutes), late-phase bronchoconstriction (maximum, 41%; +6 to 8 hours), and neutrophil infiltration (maximum, 63%; BAL, +8 hours). In conscious sheep, inhaled BI-L-239 provided dose-dependent inhibition of the inhaled Ascaris-induced late-phase bronchoconstriction (maximum, 66%; +6 to 8 hours) and increase in airway responsiveness (maximum, 82%; carbachol, +24 hours). The acute bronchoconstriction was shortened, and neutrophil infiltration diminished (maximum, 61%; BAL, +8 hours) in this model. Finally in conscious actively sensitized guinea pigs pretreated with pyrilamine and indomethacin, inhaled BI-L-239 attenuated acute bronchoconstriction (maximum, 80%; +5 to 15 minutes), leukocyte infiltration (58%; BAL, +3 days) and increase in airway responsiveness (100%; methacholine, +3 days) induced by three alternate-day ovalbumin inhalations.. In conclusion, results in these three animal models indicate that 5-lipoxygenase products may be major contributors to the bronchoconstriction (especially late phase), leukocyte infiltration, and airway hyperresponsiveness that characterize asthma.

Topics: Animals; Arachidonate 5-Lipoxygenase; Asthma; Bronchoconstriction; Dose-Response Relationship, Drug; Guinea Pigs; Humans; Lipoxygenase Inhibitors; Macaca fascicularis; Male; Phenols; Prostaglandin D2; Sheep; SRS-A

Inhaled BI-L-239 significantly inhibited i-LTC4 generation, late-phase bronchoconstriction and the influx of neutrophils into the lungs. We conclude that leukotriene generation and release within the lungs, following allergen exposure, in part mediate altered lung function and contribute to the development of airway inflammation. As such, treatment with a selective 5-lipoxygenase inhibitor may aid in the treatment of bronchial asthma and other allergic diseases.

Topics: Administration, Intranasal; Aerosols; Animals; Antigens; Beclomethasone; Bronchoalveolar Lavage Fluid; Bronchoconstriction; Dexamethasone; Leukotrienes; Lipoxygenase Inhibitors; Macaca fascicularis; Male; Phenols; Prostaglandin D2; SRS-A