Bone resorption in cholesteatoma: epithelial-mesenchymal cell interaction and collagenase production.

Clinical evidence has shown that chronic otitis media with cholesteatoma causes greater bone resorption than otitis media without cholesteatoma. What is the role of the epithelium and its products on the morbidity of cholesteatoma? We have studied the mechanism of collagenase production in cultures of rat epidermal cells and skin fibroblast-like cells under various conditions. The epithelial cells significantly induced mesenchymal cells to produce collagenase. We conclude that interaction between epithelial cells and fibroblast-like cells enhances production of collagenase. This enhancement of proteolytic activity may be crucial in the series of molecular events resulting in bone resorption associated with cholesteatoma.