Clinical Significance of Expression of Plasminogen Activatiors in Aural Cholesteatoma

Kim, Hyung Jong; Kim, Jin Hwan; Lim, Hyun Joon

Abstract

BACKGROUND AND OBJECTIVES: Bone destruction is characteristic of aural cholesteatoma. Plasminogen activator (PA), one of serine proteases, acts as the specific trigger in a proteolytic cascade, which may play a certain role in cholesteatomatous destruction. We investigated the relationship between the degree of PA expression and clinical severity of cholesteatoma. MAERIALS AND METHODS: Twenty six gerbilline cholesteatomas and 22 human cholesteatoma tissues were used. Immunohistochemical stainings were performed using antibodies against urokinase type-PA (u-PA) and tissue type-PA (t-PA), respectively. The degrees of expressions of both PAs were scored by a pathologist using a four step grading system of one negative to three positives, and were also objectively measured by an image analysis program using the black and white densitometry. Clinical stages in animal cholesteatoma and the presence of preoperative otorrhea, ossicular destruction, bone destroying complications, type and extent of cholesteatoma in a human group were used as clinical parameters in determing the disease severity.
RESULTS
PA immunoexpressions were more intense in cholesteatoma than in normal skin, especially in suprabasal layer of the epithelium. The intensities of PA expression also increased as the stage of cholesteatoma became more advanced in an animal model. However, in human cholesteatoma, they didn't show any differences between the groups according to disease severity, although there was a difference of PA expression between the pars tensa and flaccida type cholesteatomas.
CONCLUSION
PA may play a role in the pathogenesis, and possibly progression, of aural cholesteatoma.