Possible participation of acidic pH in bone resorption in middle ear cholesteatoma

Authors

  • Khac-Hung Nguyen MD, MSc,

    1. Department of Otorhinolaryngology, Thai Nguyen University of Medicine and Pharmacy, Thai Nguyen, Vietnam
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  • Hideaki Suzuki MD, PhD,

    Corresponding author
    1. Department of Otorhinolaryngology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
    • Send correspondence to Hideaki Suzuki, MD, PhD, Department of Otorhinolaryngology, School of Medicine, University of Occupational and Environmental Health, Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan. E-mail: suzuhyde@med.uoeh-u.ac.jp

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  • Toyoaki Ohbuchi MD,

    1. Department of Otorhinolaryngology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
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  • Tetsuro Wakasugi MD,

    1. Department of Otorhinolaryngology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
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  • Hiroki Koizumi MD,

    1. Department of Otorhinolaryngology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
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  • Koichi Hashida MD,

    1. Department of Otorhinolaryngology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
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  • Ryoko Baba PhD,

    1. Department of Anatomy, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
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  • Hiroyuki Morimoto DDS, PhD,

    1. Department of Anatomy, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
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  • Yoshiaki Doi MD, PhD

    1. Department of Anatomy, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
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  • This work was supported by a Grant-in-Aid for Scientific Research (C) (no. 18591893; 2010-2012) from the Japan Society for the Promotion of Science. The study protocols were approved by the Institutional Review Board of the University of Occupational and Environmental Health. The first and second authors (K.-H.N., H.S.) contributed equally to this work. The authors have no other funding, financial relationships, or conflicts of interest to disclose.

Abstract

Objectives/Hypothesis

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.

Study Design

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.

Level of Evidence

N/A. Laryngoscope, 124:245–250, 2014

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