Up-regulation of peroxidase proliferator-activated receptor gamma in cholesteatoma.
OBJECTIVE
To evaluate the localization and expression of peroxidase proliferator-activated receptor (PPAR)gamma in cholesteatoma epithelium.


METHODS
Experimental study.


METHODS
Reverse-transcription polymerase chain reaction was performed on cholesteatoma tissues from 10 adult patients undergoing tympanomastoid surgery for middle ear cholesteatoma and on 10 samples of normal external auditory canal skin tissue. The expression levels of PPARgamma to glyceraldehyde-3-phosphate dehydrogenase transcripts were semiquantified by densitometry. We also characterized the cellular localization of the PPARgamma protein immunohistochemically. Ki-67 was also localized to compare the proliferative activity of cells in cholesteatoma epithelium and in normal external auditory canal skin.


RESULTS
PPARgamma mRNA and protein were detected in normal external auditory canal skin and in cholesteatoma epithelium. The expression level of PPARgamma mRNA in cholesteatoma was significantly increased compared with that in normal external auditory canal skin. PPARgamma protein was expressed in cells mainly in the granular and prickle cell layers. However, the intensity of its expression was generally decreased in the parabasal layer of the cholesteatoma epithelium. Ki-67 was expressed in the nuclei of cells in the basal and parabasal layers, and a greater number of cells were Ki-67 immunopositive in cholesteatoma epithelium.


CONCLUSIONS
PPARgamma is up-regulated in the cholesteatoma epithelium compared with normal external auditory canal skin. These results suggest that PPARgamma may play an important role in the pathogenesis of cholesteatoma.
Hwang
Soon Jae
SJ
Department of Otorhinolaryngology-Head and Neck Surgery and Communication Disorder, Korea University College of Medicine, Seoul, Korea.
Kang
Hee Joon
HJ
Song
Jae-Jun
JJ
Kang
Jae Seong
JS
Woo
Jeong Soo
JS
Chae
Sung Won
SW
Lee
Heung-Man
HM
D000328:Adult; D015415:Biomarkers / Q000032:analysis; D001707:Biopsy, Needle; D016022:Case-Control Studies; D018424:Cholesteatoma, Middle Ear / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D013506:Otologic Surgical Procedures / Q000379:methods; D047492:Peroxisome Proliferator-Activated Receptors / Q000032:analysis / Q000378:metabolism*; D011336:Probability; D012333:RNA, Messenger / Q000032:analysis; D012016:Reference Values; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D015854:Up-Regulation
D015415:Biomarkers; D019394:Ki-67 Antigen; D047492:Peroxisome Proliferator-Activated Receptors; D012333:RNA, Messenger