Mitotic activity of keratinocytes in nifedipine- and immunosuppressive medication-induced gingival overgrowth.
BACKGROUND
The purpose of the study was to compare mitotic activity in the basal cell layer of normal human gingiva and in nifedipine- and immunosuppressive medication-induced gingival overgrowth.


METHODS
Gingival samples were collected from 19 generally healthy individuals, 12 nifedipine-medicated cardiac patients, and 22 immunosuppression-medicated (azathioprine, prednisolone, and cyclosporin A) organ transplant recipients. The transplant recipients were divided into those not taking nifedipine and those taking nifedipine. Cryostat sections were stained with monoclonal antibody for Ki-67, using an avidin-biotin-enzyme complex method. The mitotic activities of epithelial cells were determined as percentages of Ki-67 labeled cells in relation to total numbers of epithelial cells in the basal layer of oral, oral sulcular, and sulcular epithelium.


RESULTS
Mitotic activities were significantly higher in all 3 medication groups in the oral epithelium (P < or =0.003), and in the immunosuppression group in the sulcular epithelium (P= 0.032) than in the controls. In the oral sulcular epithelium, mitotic activity was fairly similar in all medication groups. In the nifedipine group a significant negative correlation was found between duration of nifedipine medication and the percentage of Ki-67 labeled cells in the oral epithelium (P= 0.025).


CONCLUSIONS
The results suggest that the increased epithelial thickness observed in nifedipine- and cyclosporin A-induced gingival overgrowth is associated with increased mitotic activity, especially in the oral epithelium.
Nurmenniemi
P K
PK
Institute of Dentistry, University of Oulu, Finland.
Pernu
H E
HE
Knuuttila
M L
ML
D000328:Adult; D000368:Aged; D001379:Azathioprine / Q000009:adverse effects; D002121:Calcium Channel Blockers / Q000009:adverse effects*; D002452:Cell Count; D016572:Cyclosporine / Q000009:adverse effects; D004847:Epithelial Cells / Q000187:drug effects / Q000473:pathology; D004848:Epithelium / Q000187:drug effects / Q000473:pathology; D005260:Female; D005881:Gingiva / Q000187:drug effects* / Q000473:pathology; D019214:Gingival Overgrowth / Q000139:chemically induced* / Q000473:pathology; D005938:Glucocorticoids / Q000009:adverse effects; D006331:Heart Diseases / Q000188:drug therapy; D006801:Humans; D007124:Immunoenzyme Techniques; D007166:Immunosuppressive Agents / Q000009:adverse effects*; D015603:Keratinocytes / Q000187:drug effects* / Q000473:pathology; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D008875:Middle Aged; D008938:Mitosis / Q000187:drug effects*; D009543:Nifedipine / Q000009:adverse effects*; D016377:Organ Transplantation; D011239:Prednisolone / Q000009:adverse effects; D013223:Statistics as Topic; D018709:Statistics, Nonparametric
D002121:Calcium Channel Blockers; D005938:Glucocorticoids; D007166:Immunosuppressive Agents; D019394:Ki-67 Antigen; D016572:Cyclosporine; D011239:Prednisolone; D009543:Nifedipine; D001379:Azathioprine