title: Expression of a cathelicidin antimicrobial peptide is augmented in cholesteatoma.
abstract: OBJECTIVE
  Antimicrobial peptides are active defense components of innate immunity. Their importance was confirmed at epithelial surfaces as immediate barrier effectors in preventing infection. Cathelicidins are peptide antibiotics that are receiving increasing attention. Several studies have shown that overexpression of cathelicidin results in augmented protection against bacterial infection and prevention of local infection and systemic invasion of microbes. The goal of the study was to investigate whether cathelicidin is upregulated in cholesteatoma epithelium compared with normal skin.
  
  
  METHODS
  Twenty patients from a prospective study of cholesteatoma tissues and normal skins were enrolled in the study. The specimens were divided into two portions. One portion was used for subsequent RNA studies; the other was used for immunohistochemical staining.
  
  
  METHODS
  Reverse transcriptase-polymerase chain reaction was used to assess the expression levels of cathelicidin messenger RNA (mRNA) both in cholesteatoma and in normal skin. Presumptive concentration of cathelicidin mRNA and beta2-microglobulin mRNA was evaluated. Ratio of beta2-microglobulin to cathelicidin was analyzed in each group. The expressions of cathelicidin in cholesteatoma and normal skin epithelium were investigated by an immunohistochemical technique.
  
  
  RESULTS
  Cathelicidin mRNA in cholesteatoma epithelium was increased 5.5-fold compared with normal skin of the ear canal. In cholesteatoma epithelium, cathelicidin was located in all the layers, but in the normal skin it was expressed only in the granular and prickle cell layers.
  
  
  CONCLUSIONS
  Cathelicidin is augmented in cholesteatoma epithelium, and the data in the present study are in agreement with the hypothesis that cathelicidin is likely to act as a key component in the first line of defense at the surface epithelium.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Korea University, Guro Hospital, 80 Guro-dong, Guro-gu, Seoul 152-702, Korea.
authors.forename: Hak Hyun
authors.initials: HH
authors.lastname: Jung
authors.forename: Sung Won
authors.initials: SW
authors.lastname: Chae
authors.forename: Seol Ki
authors.initials: SK
authors.lastname: Jung
authors.forename: Seon Tae
authors.initials: ST
authors.lastname: Kim
authors.forename: Heung Man
authors.initials: HM
authors.lastname: Lee
authors.forename: Soon Jae
authors.initials: SJ
authors.lastname: Hwang
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism*; D018424:Cholesteatoma, Middle Ear / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D046508:Culture Techniques; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D010455:Peptides; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011446:Prospective Studies; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D001613:beta 2-Microglobulin / Q000235:genetics / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D018076:DNA, Complementary; D010455:Peptides; D012333:RNA, Messenger; D001613:beta 2-Microglobulin