Expression of transforming growth factor-beta receptor II mRNA in cyclosporine-induced gingival overgrowth.

Gingival overgrowth (GO), characterized by increased cellular and extracellular matrix components in gingival tissue, is a frequent side effect of cyclosporine (CsA). In previous studies, elevated levels of transforming growth factor-beta (TGF-beta) have been detected in GO tissue, which led to the conclusion that TGF-beta plays a major part in the pathogenesis. TGF-beta activity is mediated by three receptors; TGF-beta receptor II (TGF-beta RII), the most important, has been immunohistochemically detected in GO and normal gingival tissue. The aim of this study was to clarify whether TGF-beta RII is overexpressed in CsA-induced GO. The expression of TGF-beta RII mRNA in GO tissue of patients on CsA (n = 10, 5 women, aged 42.5 +/- 14.9 years) with renal transplantation (transplant duration 3.6 +/- 0.96 years) was compared with that in healthy gingiva of control subjects (n = 10, 5 women, aged 42.5 +/- 7.6 years). Semiquantitative reverse transcribed-polymerase chain reactions (RT-PCR) were applied with glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as an internal standard. TGF-beta RII mRNA was readily detected in the GO tissue of patients on CsA. The level of TGF-beta RII mRNA relative to GAPDH in GO cases was not significantly higher than the relative TGF-beta mRNA level in normal gingiva (0.60 +/- 0.16 vs 0.52 +/- 0.19; P = .575). The precise mechanism of CsA-induced GO remains uncertain. According to our results, TGF-beta RII was not upregulated in CsA-induced GO, and may have no important role in this disorder. However, the involvement of TGF-beta in the molecular pathology of GO may be mediated via TGF-beta RI or RIII.

Inhibition of experimental gingivitis in beagle dogs with topical salivary histatins.

Histatins, histidine-rich proteins found within parotid and submandibular secretions, are a novel class of endogenous peptides with antimicrobial properties. This masked, randomized, placebo-controlled preclinical investigation examined the effect of 3 topical histatins on the development of plaque and gingivitis in beagle dogs. 16, female, 1-year-old beagles were brought to optimal gingival health by mechanical scaling and polishing followed by rigorous daily tooth brushing. At the conclusion of this pretreatment period, dogs were randomly divided into 4 groups for the application of test formulations, and were placed on a plaque-promoting diet. Test agents included 3 synthetic salivary histatins (histatin 5, P-113 and P-113D) which were incorporated in hydroxypropyl methylcellulose gel at a concentration of 0.125%, and a placebo, or negative control, which was the gel vehicle alone. Throughout the 10-week treatment period, test formulations (2.0 ml) were applied 2 x daily to all premolar teeth using a Monojet syringe. Plaque formation and gingival inflammation were assessed using the plaque (PI) and gingival (GI) indices on days 0, 7, 14, 21, 28, 42, 56 and 70. Furthermore, bleeding to probing was recorded as a percent of sites (%BOP) and according to the modified sulcus bleeding index (mSBI). Comparisons among groups and between group pairs (active versus placebo) were made with Kruskal-Wallis tests with the average of data over the interval, days 14-42, being the primary focus of the analysis. From baseline to day 7, all groups expressed similar indices. Thereafter, overall significant differences among the groups were noted at day 42 for PI, at days 21, 28, 42 and 70 for GI, and at days 14 and 28 for %BOP (p < 0.05). In particular, beagles treated with P-113 demonstrated significantly lower PI scores at day 42 (p < 0.05), significantly lower GI scores from days 21 through 42 (p < 0.05), and significantly lower %BOP scores at days 14 and 28 (p < 0.05) compared to beagles treated with placebo. Beagles treated with P-113D exhibited significantly lower GI at day 42 compared to the placebo (p < 0.05). For the primary analysis conducted over the midtreatment interval (days 14-42), significant differences were detected for all parameters except mSBI (p < 0.05). Accordingly, significantly lower PI scores were found for P-113, lower GI scores for P-113 and P-113D, and lower %BOP for P-113 and P-113D compared to placebo (p < 0.05). These data indicate that in the beagle model, salivary histatins, P-113 and P-113D, topically applied, can significantly reduce clinical signs of plaque formation and gingival inflammation.