Human Cholesteatoma Debris is Chemotactic for Monocytes

Abstract

Our previous studies have shown that cholesteatoma debris (ChD) stimulates macrophages to produce active oxygen species and a bone resorbing cytokine, tumor necrosis factor. Here we tested if ChD would induce chemotaxis of human peripheral blood monocytes, in vitro, using a microchamber technique. ChD induced migration of monocytes across Nuclepore filters. Although ChD contained lipopolysaccharides (LPS), minimal migration of monocytes to LPS was observed at concentrations of lOng to 10 μg/ml. On the other hand, 8M-urea-extracts from ChD, which consisted mainly of α-keratin, induced migratory response of monocytes, and showed a bell-shaped dose-response relation. From these results, we suggest that ChD initiates bone resorption through chemotaxis and activation of macrophages.