Growth factors influence growth and differentiation of the middle ear mucosa

Objective: Otitis media is a major cause of morbidity in pediatric and adul t patients, This inflammatory condition is characterized by mucosal hyperpl asia that is thought to be mediated by the complex actions of growth factor s and their respective receptors. It was the purpose of this study to deter mine which growth factors might be responsible for the growth and different iation of the middle ear epithelium during otitis media, Study Design: The effect of several growth factors on the expansion and differentiation of no rmal middle ear mucosa was evaluated in tissue culture. Materials and Metho ds: Explants of normal rat middle ear mucosa were exposed in vitro to six d ifferent growth factors known to influence epithelial cells in other tissue s: epidermal growth factor, ampphiregulin, betacellulin, heregulin-alpha, k eratinocyte growth factor, and hepatocyte growth factor. Results: After 12 days, the growth and level of cytokeratin expression were analyzed for each of the explant outgrowths. Each factor appeared to have a significant, con centration-dependent effect on either the growth or differentiation of the cultured middle ear epithelial cells. Conclusion: The results suggest that several of the tested growth factors may play a significant role in control ling hyperplasia of the middle ear mucosa during otitis media.