dinoprost and Otitis-Media-with-Effusion

Although previous studies have shown that prostaglandins (PGs), leukotrienes (LTs), and other arachidonic acid (AA) metabolites play an important role in the pathogenesis of otitis media with effusion (OME), the exact role of each AA metabolite in OME is still unknown. The purpose of this study was to examine the effect of several individual AA metabolites alone or in combination and AA itself on experimental otitis media in chinchillas. Normal chinchillas were inoculated daily with normal saline, PGE2, LTC4, LTC4 + PGE2, and AA through the superior bullae over 7 days. Animals were followed by otoscopy and tympanometry, samples of middle ear effusion were collected for biochemical assay, and temporal bones were processed for histopathology. The highest number of ears that developed OME was in the group inoculated with PGE2 + LTC4. The degree of inflammatory change was more pronounced in groups injected with LTC4 than any other group. The findings of this study suggest that eicosanoids PGE2, LTC4, and AA alone or in combination inoculated into the middle ear can induce OME.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Arachidonic Acid; Arachidonic Acids; Chinchilla; Dinoprost; Dinoprostone; Hydroxyeicosatetraenoic Acids; Leukocytes; Leukotriene B4; Mucous Membrane; Muramidase; Otitis Media with Effusion; Prostaglandin D2; SRS-A

Otitis media with effusion (OME) is a common middle ear inflammatory disease in the pediatric population. This article determines concentrations of three functionally and metabolically distinct inflammatory mediators in middle ear effusions (MEE) and corresponding plasma of children with OME. One hundred two patients (mean age, 4.9 years) with persistent OME were studied. Middle ear effusions were collected from all subjects and plasma from a subset at the time of tympanostomy tube insertion. Histamine was assayed radioisotopically, 13,14-dihydro-15-keto-prostaglandin F2 alpha (stable PGF2 alpha metabolite) by radioimmunoassay, and neutrophil chemotactic factor of anaphylaxis by modified Boyden chamber. Mean MEE levels of the mediators (39 +/- 13 ng/mL, 462 +/- 179 pg/mL, and 264% +/- 57% positive control, respectively) were markedly higher than those of corresponding plasma (0.5 +/- 0.1 ng/mL, 285 +/- 127 pg/mL, and 47% +/- 5% positive control, respectively). The mean histamine content of mucoid effusions (43.2 +/- 56.9 ng/mL) was significantly higher than that of purulent (22.5 +/- 10.5 ng/mL) and serous (17.9 +/- 16.8 ng/mL) effusions. Higher histamine levels were observed in effusions positive for Haemophilus influenzae when compared with those with other pathogenic isolates. The high concentrations of these mediators in MEE and their potential for inducing or sustaining the inflammatory process supports a role in the pathogenesis of OME.

Topics: Adolescent; Adult; Chemotactic Factors; Child; Child, Preschool; Chronic Disease; Dinoprost; Haemophilus influenzae; Histamine; Humans; Infant; Inflammation; Interleukin-8; Otitis Media with Effusion; Prostaglandins F