Cytokeratin expression in palatal and marginal mucosa of cleft palate patients.
OBJECTIVE
The margin of a palatal cleft is a unique anatomical site since the palatal mucosa is continuous with the nasal or nasopharyngeal mucosa. The aim of this study was to compare the expression patterns of cytokeratins and basal membrane components of the mucosa in the area of the cleft.


METHODS
Biopsies from the mucosa of the hard palate and from the cleft margin in the soft palate were obtained from five patients during the primary surgical closure of the cleft. The tissues were processed for haematoxylin-eosin staining and for immunohistochemistry. Antibodies against the cytokeratins (CK) 4, 7, 8, 10, 13, 16 and 18, and the basal membrane components heparan sulphate (HS) and collagen type IV (CIV) were used for immunostaining.


RESULTS
The nasopharyngeal epithelium was thinner than the epithelium of the soft palatal mucosa, and showed less interpapillary ridges. The nasopharyngeal epithelium was stratified but expressed the keratins of a simple epithelium (CK 7, 8 and 18). The expression pattern abruptly changed into that of a typical non-keratinized stratified epithelium (CK 4, 13) at the transition to the soft palatal epithelium. The epithelium of the hard palate was a fully differentiated, keratinized and stratified epithelium (CK 10, 16). The basal membrane was thinner in the nasopharyngeal epithelium, which might be related to the presence of abundant inflammatory cells.


CONCLUSIONS
The area around the palatal cleft showed three different types of epithelium. There was an abrupt transition in phenotype of the epithelium from the oral side to the nasopharyngeal side.
Guo
Ji H
JH
Key Laboratory of Oral Biomedical Engineering of Ministry of Education, School and Hospital of Stomatology, Wuhan University, 65 Luoyo Road, Postal Code 430079, Wuhan, PR China.
Maltha
Jaap C
JC
He
San G
SG
Krapels
Ingrid P C
IP
Spauwen
Paul H M
PH
Steegers-Theunissen
Regien P M
RP
Von den Hoff
Johannes W
JW
D002675:Child, Preschool; D002972:Cleft Palate / Q000378:metabolism* / Q000473:pathology; D004848:Epithelium / Q000737:chemistry / Q000473:pathology; D006801:Humans; D007223:Infant; D007633:Keratins / Q000032:analysis*; D009061:Mouth Mucosa / Q000737:chemistry* / Q000473:pathology; D009305:Nasopharynx / Q000737:chemistry* / Q000473:pathology; D021362:Palate, Hard / Q000737:chemistry* / Q000473:pathology
D007633:Keratins