title: Matrix metalloproteinase imbalance in inguinal hernia formation.
abstract: BACKGROUND
  Emerging evidence supports the role of matrix metalloproteinases (MMPs) in hernia formation. However, the imbalance between the proteolytic activity of MMPs and their endogenous inhibitors (TIMPs) has not been investigated. The aim of the present study was to determine changes of MMP and TIMP levels in patients with inguinal hernia.
  
  
  METHODS
  Two matrix metalloproteinases (MMP-9 and MMP-2) and their main inhibitors TIMP-1 and TIMP-2 were evaluated in consecutive patients undergoing inguinal hernia repair and control subjects. MMP/TIMP quantification was performed using ELISA in abdominal fascia tissue specimens and preoperative plasma samples.
  
  
  RESULTS
  Tissue explants from hernia patients produced significantly higher levels of MMP-9 and MMP-2, and reduced TIMP-1 and TIMP-2 concentrations compared to those of controls. In plasma, a reverse correlation was found regarding the concentrations of MMPs; the circulating levels of MMP-9 and MMP-2 were significantly lower in patients with inguinal hernia than controls. Furthermore, hernia patients were found to have elevated plasma levels of TIMP-2 and reduced plasma levels of TIMP-1.
  
  
  CONCLUSIONS
  The imbalance in MMP/TIMP activity indicates a dysregulation of the extracellular matrix degradation process in patients with inguinal hernia. The results of the present study suggest that impaired collagen metabolism may be an underlying pathophysiological mechanism of inguinal hernia formation.
authors.affiliation: Department of Vascular Surgery, Demokritos University of Thrace, Alexandroupolis, Greece. antoniou.ga@hotmail.com
authors.forename: George A
authors.initials: GA
authors.lastname: Antoniou
authors.forename: Ioannis K
authors.initials: IK
authors.lastname: Tentes
authors.forename: Stavros A
authors.initials: SA
authors.lastname: Antoniou
authors.forename: Constantinos
authors.initials: C
authors.lastname: Simopoulos
authors.forename: Miltos K
authors.initials: MK
authors.lastname: Lazarides
mesh_terms: D000009:Abdominal Muscles / Q000378:metabolism; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D005109:Extracellular Matrix / Q000378:metabolism; D006552:Hernia, Inguinal / Q000378:metabolism* / Q000503:physiopathology; D006801:Humans; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D008875:Middle Aged; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism
chemical_list: D015415:Biomarkers; D019715:Tissue Inhibitor of Metalloproteinase-1; D019716:Tissue Inhibitor of Metalloproteinase-2; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9