title: In situ localization and characterization of active proteases in chronically inflamed and healthy human gingival tissues.
abstract: BACKGROUND
  Studies have indicated an important role for host-derived proteases in the pathogenesis of periodontal disease. The objectives of this study were: 1) to develop an assay measuring protease activity in situ and 2) to localize and characterize the enzymatic activity in intact inflamed and healthy gingiva.
  
  
  METHODS
  Gingival specimens were prepared and over-laid with a quenched fluorescent substrate. Protease activity was visualized by fluorescence microscopy and correlated with histologic features.
  
  
  RESULTS
  In inflamed tissues, enzymatic activity was detected mainly in the connective tissue (predominantly matrix metalloproteases) and, to some extent, in the epithelium (predominantly serine proteases). In contrast, clinically healthy tissues failed to exhibit significant amounts of protease activity. Quantitative and qualitative characteristics of protease activity in intact tissues were found to be pH dependent.
  
  
  CONCLUSIONS
  The method described here enabled assessment of active proteases in intact tissues where cell-cell and cell-matrix interactions had been maintained. Our results indicate that there are substantial differences in the distribution of specific proteases between clinically healthy and inflamed periodontal tissues.
authors.affiliation: Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, USA. sarment@umich.edu
authors.forename: D P
authors.initials: DP
authors.lastname: Sarment
authors.forename: J
authors.initials: J
authors.lastname: Korostoff
authors.forename: M
authors.initials: M
authors.lastname: D'Angelo
authors.forename: A M
authors.initials: AM
authors.lastname: Polson
authors.forename: R S
authors.initials: RS
authors.lastname: Feldman
authors.forename: P C
authors.initials: PC
authors.lastname: Billings
mesh_terms: D000328:Adult; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000032:analysis* / Q000378:metabolism; D005881:Gingiva / Q000201:enzymology*; D005891:Gingivitis / Q000201:enzymology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D020782:Matrix Metalloproteinases / Q000032:analysis / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D012697:Serine Endopeptidases / Q000032:analysis / Q000378:metabolism; D018709:Statistics, Nonparametric; D014018:Tissue Distribution
chemical_list: D010450:Endopeptidases; D012697:Serine Endopeptidases; D020782:Matrix Metalloproteinases