title: Immunohistochemical investigations of cathepsin D activity in the structures of cholesteatoma.
abstract: BACKGROUND
  Cathepsin D decomposes cytoplasmic proteins, cell organelles, collagen, elastase and proteoglycans. It takes part in angiogenesis and activates osteoclasts, and is thought to play a major role in the destruction of bone tissue by cholesteatoma. The aim of the present study was to evaluate the activity of cathepsin D in the structures of cholesteatoma.
  
  
  METHODS
  Cholesteatomas were collected from 16 patients operated on for chronic inflammation of the middle ear. Specimens were fixed in formalin at pH 7.2, after which parrafin slices were made. Cathepsin D was assayed with a Dako set. Keratin was measured by the Kreyberg method. Normal skin from behind the ear was taken from the patients during the same operation. The samples included a stratified, desquamative epithelium (matrix), a streak containing connective tissue (perimatrix), and a mass of keratin debris.
  
  
  RESULTS
  Cathepsin D demonstrates high activity in perimatrix cells adjacent to bone tissue, while it occurs in trace amounts in the matrix. A highly positive reaction was observed within keratin, which was present in the superficial layer of the epithelium. Pseudocathepsin located in desquamative epithelial cells demonstrated a high positive reaction. There were trace amounts of cathepsin D within the dermis. In the control group (the skin samples), there were trace amounts of cathepsin D within the corneous layer of the epithelium.
  
  
  CONCLUSIONS
  Cathepsin D places a major role in bone tissue destruction due to cholesteatoma.
authors.affiliation: Department of Otolaryngology, Medical Academy in Białystok, Białystaok, Poland. ewaolsz@yahoo.com
authors.forename: Stanisław
authors.initials: S
authors.lastname: Chodynicki
authors.forename: Lech
authors.initials: L
authors.lastname: Chyczewski
authors.forename: Ewa
authors.initials: E
authors.lastname: Olszewska
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017209:Apoptosis; D001842:Bone and Bones / Q000378:metabolism / Q000473:pathology; D002402:Cathepsin D / Q000378:metabolism*; D018424:Cholesteatoma, Middle Ear / Q000378:metabolism* / Q000601:surgery*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged
chemical_list: D002402:Cathepsin D