INFLAMMATORY MECHANISMS IN VIRAL OTITIS MEDIA

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Acute otitis media (AOM) and viral upper respiratory tract infections (URIs) represent the two most common diseases affecting the human population, and account for substantial patient morbidity and health care costs. Epidemiological and experimental studies suggest that URIs play a causal role in the pathogenesis of AOM. Specifically, viruses can invade the middle ear (ME) space and invoke an inflammatory response that culminates in ME effusion (fluid) formation and consequent symptoms (pain, hearing loss). The molecular events responsible for the inflammatory response of the human ME following viral exposure have not been characterized. Studies using viral inoculation of nasal and tracheobronchial tissues suggest that the initiating inflammatory events are epithelium-mediated through local cytokine production. Since the ME normally does not contain aggregates of leukocytes, it is likely that the initiating events in viral otitis media are epithelium-mediated as well. The long-term goal of the present study is to investigate the ME mucosal response(s) to viral exposure in an effort to better understand the initiating events in AOM. Such knowledge will help develop new therapies for this significant disease. The goals of this project are to: (1) perform influenza A viral challenge experiments in the laboratory's normal ME epithelial cell culture system and measure expression of the interleukin (IL,)-1alpha, IL-1beta, IL-6, IL-8, IL-10 and tumor necrosis factor (TNF)-alpha genes using reverse transcriptase- polymerase chain reaction (RT-PCR), in situ hybridization, and enzyme-linked immunoabsorbent assays (ELISA); (2) evaluate the same cytokine responses in ME epithelial cells derived from "otitis-prone" individuals; and (3) evaluate the efficacy of several potentially inhibitory substances in these models. The results of these experiments will provide a better understanding of the initiating events in viral otitis media and, hopefully, will lead to the development of novel therapies for this disease. Successful completion of this award by the principal investigator (PI) will provide the added research training and career development for future large-scale studies as an independent investigator.