title: Expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases in pigmented villonodular synovitis suggests their potential role for joint destruction.
abstract: OBJECTIVE
  Pigmented villonodular synovitis (PVNS) is an uncommon idiopathic, proliferative synovial disease. Since matrix metalloproteinases (MMP) are assumed to play an important role in the pathogenesis of PVNS, we examined the expression and activity of MMP and tissue inhibitor of metalloproteinases (TIMP) in PVNS.
  
  
  METHODS
  Synovial tissue samples were obtained from 10 patients with PVNS (knee 8, ankle 2) and 4 patients each with rheumatoid arthritis (RA) or osteoarthritis (OA) for comparison. Protein deposition and mRNA expression were determined by conventional immunohistochemical studies and reverse transcription-polymerase chain reaction (RT-PCR), respectively. Gelatin zymography was performed for detection of gelatin-degrading activity. The quantity of MMP and TIMP was measured by ELISA.
  
  
  RESULTS
  Intense immunostaining for MMP-1 was detected in both the multinucleated giant cells and mononuclear cells, whereas TIMP-1 was weakly positive. MMP-9 immunostained predominantly in the multinucleated cells, whereas other MMP and TIMP were weakly detected. RT-PCR analysis showed that mRNA expression of MMP-9 was stimulated in PVNS, whereas MMP-2 mRNA was not, compared to RA or OA. The gelatin zymogram indicated protease activities predominantly at 92 kDa and 67 kDa. In accord with the immunostaining results, the amount of MMP-1 and MMP-9 protein was significantly higher than that of TIMP-1 and MMP-2, respectively.
  
  
  CONCLUSIONS
  We characterized the expression and activity of MMP in PVNS and observed that PVNS tissues predominantly produce MMP-1 and MMP-9. Given that PVNS occasionally induces joint destruction, stimulated expression of MMP-1 and MMP-9 may contribute to the invasive activity and the bone and cartilage loss in PVNS.
authors.affiliation: Department of Orthopaedic Surgery, Aichi Prefectural Hospital, Aichi, Japan.
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Uchibori
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Nishida
authors.forename: Izuru
authors.initials: I
authors.lastname: Tabata
authors.forename: Hideshi
authors.initials: H
authors.lastname: Sugiura
authors.forename: Hiroatsu
authors.initials: H
authors.lastname: Nakashima
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Yamada
authors.forename: Naoki
authors.initials: N
authors.lastname: Ishiguro
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003470:Culture Media; D046508:Culture Techniques; D005260:Female; D005780:Gelatin; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007596:Joints / Q000378:metabolism / Q000473:pathology; D008297:Male; D020781:Matrix Metalloproteinase 1 / Q000235:genetics* / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013586:Synovitis, Pigmented Villonodular / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology*; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics* / Q000378:metabolism
chemical_list: D003470:Culture Media; D019715:Tissue Inhibitor of Metalloproteinase-1; D005780:Gelatin; D020780:Matrix Metalloproteinase 9; D020781:Matrix Metalloproteinase 1