Role of interleukin 6 in epithelial hyperproliferation and bone resorption in middle ear cholesteatomas.
Locally produced pro-inflammatory cytokines are considered to play an important role in the initiation and/or maintenance of inflammatory diseases. In cholesteatomatous lesions there are increased levels of some cytokines and inflammatory mediators like interleukin 1, tumor necrosis factor and colony-stimulating factor, etc. Interleukin 6 (IL-6) can be produced by different cells present in cholesteatoma (e.g. keratinocytes, lymphocytes, fibroblasts and macrophages). Until now, no data have been available on the role of IL-6 in cholesteatoma. In this study we used immunohistochemistry to investigate the presence and distribution of IL-6 in tissue samples from cholesteatoma patients. Levels of the cytokine were quantified in tissue extracts using an enzyme-linked immunosorbent assay. Finally, the presence of biologically active IL-6 was analyzed in the murine cell line 7TD1. Human skin samples obtained from the external ear canal were used as controls. Using the anti-IL-6 antibody in an alkaline phosphatase anti alkaline phosphatase technique, a moderate diffuse staining of the whole epidermis was observed in sections of normal skin. In cryostat sections of cholesteatoma samples, a stronger staining of the whole epithelium was observed. Many of the cells infiltrating the cholesteatoma stroma also showed positive immunostainings. The concentration of IL-6 in relation to the total protein concentration in cholesteatoma (119.33 +/- 30) were higher than in human skin (9.16 +/- 13). While IL-6 activity was not detected in skin samples, two of the ten cholesteatoma samples studied showed a stimulatory effect when incubated with the cell line 7TD1. The overexpression of IL-6 in middle ear cholesteatoma suggests a participation of this cytokine in some of the clinical features seen: epithelial hyperproliferation and bone resorption. The absence of biological activity in the majority of the cholesteatoma samples points to the presence of natural inhibitors for IL-6.
Bujía
J
J
Department of Otolaryngology, Head and Neck Surgery, Ludwig Maximilians University, Munich, Germany.
Kim
C
C
Ostos
P
P
Kastenbauer
E
E
Hültner
L
L
D001862:Bone Resorption / Q000209:etiology / Q000503:physiopathology*; D002465:Cell Movement / Q000502:physiology*; D002781:Cholesteatoma / Q000150:complications / Q000503:physiopathology*; D004432:Ear, Middle / Q000503:physiopathology* / Q000648:ultrastructure; D004797:Enzyme-Linked Immunosorbent Assay; D004848:Epithelium / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D015850:Interleukin-6 / Q000502:physiology*
D015850:Interleukin-6