A case report of multiple-drug-induced gingival overgrowth with TIMP-3 over-expression

Microarray and quantitative RT-PCR analyses in calcium-channel blockers induced gingival overgrowth tissues of periodontitis patients

OBJECTIVES

The purpose of the present study was to analyse transcriptomes and mRNA expression levels for specific genes in calcium-channel blocker-induced gingival overgrowth (GO) tissues.

DESIGN

Eight gingival tissues samples (from both GO negative and positive sites) were harvested from four GO patients for microarray analyses. Twelve candidate genes were selected for further quantitative real time reverse transcription-polymerase chain reaction (qRT-PCR) analyses. Ten GO tissues from periodontitis patients and ten control gingival tissues from healthy subjects were compared by qRT-PCR. Mann-Whitney U-test was used for statistical evaluation.

RESULTS

In GO positive tissues, 163-1631 up-regulated and 100-695 down-regulated genes were identified with more than two-fold changes compared with GO negative tissues amongst patients by microarray experiments. No commonly expressed genes amongst the eight sets of microarray data were found. The clustering analysis confirmed that the entire transcriptome patterns showed similarities in individuals, but differences amongst the four patients. The qRT-PCR and statistical analyses for the candidate genes, though, revealed differential gene expressions between GO-positive and negative tissues. We found that matrix metalloproteinase (MMP)-1 and MMP-12 as well as cathepsin-L were significantly up-regulated whilst keratin-10 and transforming growth factor-β1 were significantly down-regulated in GO tissues of periodontitis patients compared with the control gingival tissues of healthy subjects.

CONCLUSION

The microarray analyses revealed that GO pathogenesis was complex and individually varied, though GO-affected gingival tissues were controlled at least by genes related to collagen metabolisms including regulated MMPs, cathepsin-L, growth factors, and keratins to maintain tissue homeostasis in vivo.

Differential gene and protein expression of tissue inhibitors of metalloproteinases (TIMP)-3 and TIMP-4 in gingival tissues from drug induced gingival overgrowth

OBJECTIVES

The purpose of this study was to analyse mRNA expression and protein localization of tissue inhibitors of metalloproteinases (TIMP)-3 and TIMP-4 in gingival tissues removed from drug (calcium-channel blocker) induced gingival overgrowth and periodontitis patients.

DESIGN

Employing RT-PCR, we evaluated TIMP-3 and TIMP-4 mRNA levels of 20 human gingival tissue samples taken from patients suffering gingival overgrowth (GO) and periodontitis (P). Then, using immunohistochemistry we investigated the TIMP-3 and TIMP-4 protein localization of five sample tissues from each group.

RESULTS

TIMP-4 mRNA levels in GO-gingiva tended to be lower than in P-gingiva but the results differed little (p = 0.22). Varying degrees of inflammation in the protein localization of TIMP-3 and TIMP-4 were found. TIMP-4 immunoreactivity (IR) was weak in the endothelial cells, fibroblasts, epithelial basal and parabasal cells while the degree of inflammation differed as well. TIMP-3 and TIMP-4 IR in inflammatory cells, including lymphocytes, plasma cells, and macrophages, were faint and intense respectively. For P-gingiva, both TIMP-3 and TIMP-4 IR expression was weak in the endothelial cells, fibroblasts, basal and parabasal epithelial layers. Expression of TIMP-3 was faint in the inflammatory cells, whereas TIMP-4 IR was strong.

CONCLUSION

Our findings suggest that TIMP-3 and TIMP-4 expression differs in GO and P-gingival tissues, both of which are potentially involved in pathogenesis.