Possible roles of medullasin in nifedipine-induced human gingival overgrowth

In order to clarify a possible pathophysiological role of medullasin, a neutrophil elastase-like proteinase, in nifedipine (NF)-induced gingival overgrowth, the distributions of medullasin-positive cells immunostained in specimens from patients with NF-induced gingival overgrowth and chronic marginal gingivitis were compared in three different biopsy areas. Twenty gingival biopsies were obtained from five patients with gingival overgrowth and 20 biopsies from another five patients with chronic marginal gingivitis. In the marginal gingivitis group, the mean percentage of positive cells in the vicinity of pocket epithelium (zone I) was significantly higher than in the areas of connective tissue of the mid-portion (zone II) and adjacent to oral epithelium (zone III) (p < 0.05). In the gingival overgrowth group, on the contrary, the positive cells significantly increased in zone II as compared with zones I and III (p < 0.05). Further, medullasin-positive cells of zones II and III in the overgrowth group had infiltrated more extensively than those in the gingivitis group (p < 0.001), indicating the participation of this enzyme in the mechanism of NF-induced gingival overgrowth. These observations suggest that medullasin may play a part in NF-induced overgrowth both in host defence and in immunoregulation, possibly cytotoxically.