Vol. 99  No. May 2006

Proteinases Related to the Bone Destruction and those 
Inhibitors in Human Cholesteatoma of the Middle ear

Takeshi Kusunoki and Kiyotaka Murata
(Kinki University School of Medicine)

  Objective: We examined metalloproteinase-1 (MMP-1), cathepsin L, and inhibitors (tissue inhibitor of metalloproteinse-1 (TIMP-1), cystatin A, and Cu- and Zn-containing superoxide dismutase (Cu, Zn-SOD)) in human cholesteatoma of the middle ear. Using the above data, epithelia and subepithelial granulation was discussed.
Method: Cathepsin L activity in the cholesteatoma epithelium, granulation tissues in cholesteatoma, or granulation tissues in noncholesteatoma were measured using Barrett's method. Cystatin A expressions were observed by Western blot analysis. Moreover, MMP-1, TIMP-1, cathepsin L, and Cu, Zn-SOD were examined immunohistochemically.
Results: Although, MMP-1 and cathepsin L immunohistochemically showed both epithelial and subepithelial granulation, the mean cathepsin L activity was higher in subepithelial than epithelial granulation. Subepithelial granulations with high cathepsin L activity resulted in extensive bone destruction in cholesteatomas. Cystain A and Cu, Zn-SOD with inhibitors of MMP-1 and cathepsin L were more strongly positive in epithelial regions than in subepithelial granulation tissues.
Conclusion: These results suggest that the area related to bone destruction in human cholesteatoma is subepithelial granulation rather than epithelia.

Key words :
metalloproteinase-1, cathepsin, cystatin A, superoxide dismutase, human cholesteatoma

第99巻5号 目次   Vol.99 No.5 contents