Gene and protein localisation of tumour necrosis factor (TNF)-α converting enzyme in gingival tissues from periodontitis patients with drug-induced gingival overgrowth.

OBJECTIVE

It is known that tumour necrosis factor (TNF)-α converting enzyme (TACE) plays a crucial role in fibrotic inflammatory diseases, and is specifically inhibited by tissue inhibitor of metalloproteinase (TIMP)-3. Fibrotic drug-induced gingival overgrowth (GO) is often combined with periodontitis. However, neither TACE nor TIMP-3 has been thoroughly examined in periodontal tissues to date. The aim of the present study was to analyse mRNA expression of TACE and TIMP-3, and protein localisation of TACE in gingival tissues removed from drug-(calcium-channel blocker) induced GO and periodontitis.

METHODS

A total of 30 gingival tissue samples were taken from 15 GO and 15 periodontitis patients. The mRNA expression levels were analysed by quantitative reverse transcription polymerase chain-reaction (qRT-PCR) and the protein localisation was investigated by immunohistochemistry. Statistical analysis was performed using the Mann-Whitney U-test.

RESULTS

TACE and TIMP-3 mRNA levels were significantly higher in GO compared to the periodontitis groups, as revealed by qRT-PCR (p<0.05). TACE-producing cells were immunohistochemically detected among monocytes/macrophages, plasma cells and some epithelial cells. TACE immunoreactivity was shown to be more intense in GO than in periodontitis-gingival tissue.

CONCLUSIONS

We have demonstrated TACE expression in cells such as macrophages, plasma cells and epithelial cells, and its predominant expression in GO tissues. This data suggests that TACE expression in GO-gingiva could be involved in the pathogenesis of disease.