Factors for progression of periodontal diseases

Progression factors for periodontal diseases have been suggested by in vitro study of peripheral blood and gingival cells; however, those factors are not established in vivo. This investigation assessed biopsies of three groups of gingival tissues: those adjacent to a 1) < or =3 mm (normal), 2) 4-6 mm, and 3) >6 mm gingival sulcus, to determine changes in the gingival microenvironment coincident to the progression of periodontal disease. Superoxide dismutase (SOD) and catalase activity, and IL-12 and bcl-2 levels, were decreased at >6 mm; total protein and IL-6 concentrations were increased adjacent to >6 mm, as compared to < or =3 and 4-6 mm, sites. Apoptotic cells were evident only within gingiva adjacent to >6 mm sites. These data suggest that IL-12 is an important factor in the shift from a TH1 to TH2 cell profile and that a favorable gingival microenvironment for hyperinflammation may develop coincident to progression of periodontal diseases due to decreased bcl-2 and increased IL-6 concentrations within gingiva. These changes in the gingival microenvironment could impair apoptosis and promote enhanced release of reactive oxygen species (ROS) by phagocytes; decreased catalase and SOD activity could promote accumulation of ROS and result in additional tissue destruction.