Prostaglandins, leukotrienes, and other arachidonic acid metabolites in the pathogenesis of otitis media

Among the various inflammatory mediators of otitis media (OM), metabolites of arachidonic acid (AA) such as prostaglandins (PGs) and leukotrienes (LTs) appear to play an important role in the pathogenesis of otitis media. In an effort to investigate the role of AA metabolites on the pathogenesis of otitis media, concentrations of AA metabolites were measured in middle ear effusion (MEE) from human and paralleling animal models of otitis media and the effects of inhibitors of AA metabolism, antibiotics, and tympanostomy tube (TT) on the outcome of animal models of OM were studied. Concentrations of AA metabolites in MEE were higher in the younger age group. Levels of PGE2 and LTB4 in MEE seem to represent the degree of inflammation of OM best. Lipoxygenase products seem to be associated with the mucoid type of MEE. In the study of animal models of OM, combined models and ears with TT showed more inflammation than single models and ears without TT. Study of the therapeutic use of inhibitors of AA metabolism, penicillin, and TT showed that lipoxygenase products may be more important in the pathogenesis of OM than the cyclo-oxygenase products, and that the use of a combination of penicillin and corticosteroid produces the best results. It is clear from these studies that arachidonic acid metabolites are important inflammatory mediators in the pathogenesis of otitis media.