title: Possible participation of acidic pH in bone resorption in middle ear cholesteatoma.
abstract: OBJECTIVE
  The etiopathology of bone resorption in cholesteatoma is unclear. We studied pH in middle ear cholesteatoma tissue and the permeability of the cholesteatoma epithelium in an attempt to elucidate the mechanism of bone resorption in this disease.
  
  
  METHODS
  Laboratorial study.
  
  
  METHODS
  Cholesteatoma tissue was collected from patients with primary acquired middle ear cholesteatoma. The pH of the keratin debris of cholesteatoma was measured using a pH meter. The cholesteatoma epithelium was examined under a confocal laser scanning microscope, and under a transmission electron microscope. Expression of filaggrin in the cholesteatoma tissue was explored by fluorescence immunohistochemistry and by quantitative reverse transcription-polymerase chain reaction.
  
  
  RESULTS
  The pH of the keratin debris of cholesteatoma was acidic. The pH of the basal layer of the cholesteatoma epithelium was significantly lower than that of the antrum mucosa. Transmission electron microscope showed distinct penetration of lanthanum in the intercellular space of the basal, spinous, and granular layers of the cholesteatoma epithelium, but only a small amount of lanthanum in the granular layer in the normal skin. The expression of filaggrin mRNA was significantly lower in the cholesteatoma tissue than in the normal skin.
  
  
  CONCLUSIONS
  These results indicate that acid leakage through the cholesteatoma epithelium probably participates in the resorption of the underlying bone structure. The increased permeability of the cholesteatoma epithelium may be explained by a decrease in filaggrin expression.
authors.affiliation: Department of Otorhinolaryngology, Thai Nguyen University of Medicine and Pharmacy, Thai Nguyen, Vietnam.
authors.forename: Khac-Hung
authors.initials: KH
authors.lastname: Nguyen
authors.forename: Hideaki
authors.initials: H
authors.lastname: Suzuki
authors.forename: Toyoaki
authors.initials: T
authors.lastname: Ohbuchi
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Wakasugi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Koizumi
authors.forename: Koichi
authors.initials: K
authors.lastname: Hashida
authors.forename: Ryoko
authors.initials: R
authors.lastname: Baba
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Morimoto
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Doi
mesh_terms: D001862:Bone Resorption / Q000209:etiology* / Q000378:metabolism*; D018424:Cholesteatoma, Middle Ear / Q000150:complications*; D004848:Epithelium / Q000378:metabolism; D000091344:Filaggrin Proteins; D006801:Humans; D006863:Hydrogen-Ion Concentration
keywords: Cholesteatoma; bone resorption; filaggrin; pH; permeability