title: Expression of matrix metalloproteinases 1, 3, and 9 in differing extents of tendon retraction in the torn rotator cuff.
abstract: OBJECTIVE
  Differing extents of tendon retraction are found in full-thickness rotator cuff tears. The pathophysiologic context of tendon degeneration and the extent of tendon retraction are unclear. Tendon integrity depends on the extracellular matrix, which is regulated by matrix metalloproteinases (MMP). It is unknown which enzymes play a role in tendon degeneration. The hypotheses are that (1) the expression of MMPs 1, 3, and 9 is altered in the torn rotator cuff when compared with healthy tendon samples; and (2) that there is a relationship between MMP expression and the extent of tendon retraction in the torn cuff.
  
  
  METHODS
  Rotator cuff tendon samples of 33 patients with full-thickness rotator cuff tears (Bateman grade III) were harvested during reconstructive surgery. Samples were dehydrated and paraffin-embedded. Immunohistologic determination of MMP 1, 3, and 9 expression was performed by staining sample slices with MMP antibody. The extent of tendon retraction was determined intraoperatively according to Patte's classification and patients were assigned to 4 groups (control group, and by tendon retraction grade Patte I-III). The control group consisted of six healthy tendon samples.
  
  
  RESULTS
  Expression of MMPs 1 and 9 was significantly higher in torn cuff samples than in healthy tendons whereas MMP 3 expression was significantly decreased (P < 0.05). MMP 9 expression significantly increased with rising extent of tendon retraction in the torn cuff (P < 0.05). No significant association was found between expression of MMPs 1 and 3 and the rising extent of tendon retraction by Patte's classification.
  
  
  CONCLUSIONS
  Elevated expression of MMPs 1 and 9 as well as decreased MMP 3 expression can be detected in torn rotator cuff tendon tissue. There is a significant association between the extent of tendon retraction and MMP 9 expression. The results of this study give evidence that early surgical treatment of small and partial-thickness rotator cuff tears is required.
authors.affiliation: Department of Orthopedics and Rheumatology, University Hospital Marburg, Baldingerstrasse, 35043, Marburg, Germany. lakemeie@med.uni-marburg.de
authors.forename: Stefan
authors.initials: S
authors.lastname: Lakemeier
authors.forename: Juliane
authors.initials: J
authors.lastname: Braun
authors.forename: Turgay
authors.initials: T
authors.lastname: Efe
authors.forename: Christian
authors.initials: C
authors.lastname: Foelsch
authors.forename: Eleni
authors.initials: E
authors.lastname: Archontidou-Aprin
authors.forename: Susanne
authors.initials: S
authors.lastname: Fuchs-Winkelmann
authors.forename: Juergen R J
authors.initials: JR
authors.lastname: Paletta
authors.forename: Markus D
authors.initials: MD
authors.lastname: Schofer
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D020781:Matrix Metalloproteinase 1 / Q000378:metabolism*; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D008875:Middle Aged; D017006:Rotator Cuff / Q000201:enzymology* / Q000473:pathology / Q000601:surgery; D000070636:Rotator Cuff Injuries; D013708:Tendon Injuries / Q000201:enzymology* / Q000601:surgery
chemical_list: D019278:Matrix Metalloproteinase 3; D020780:Matrix Metalloproteinase 9; C522360:MMP1 protein, human; D020781:Matrix Metalloproteinase 1