title: A local imbalance between MMP and TIMP may have an implication on the severity and course of appendicitis.
abstract: BACKGROUND
  Matrix metalloproteinases (MMPs) and the tissue inhibitors of MMPs (TIMPs) have been demonstrated to be involved in inflammatory conditions in the intestine. The purpose of this study was to investigate whether the alterations of the MMP/TIMP balance might reflect the course of the inflammatory process in acute appendicitis and if the expression and localisation of MMPs and TIMP is variable in the various clinical manifestations of appendicitis.
  
  
  METHODS
  The study comprises 40 patients (26 men and 14 women) having emergency appendectomy and a control group constituting of 10 patients (5 men and 5 women) having a hemicolectomy for other reasons. MMP and TIMP expressions were assessed and compared in tissue specimens from phlegmonous (n = 15), gangrenous (n = 7), perforated appendicitis (n = 11) and controls with noninflamed appendices (n = 10) by means of enzyme-linked immunosorbent assay technique. Localisation of the enzymes was performed by immunohistochemistry.
  
  
  RESULTS
  MMP-1 was significantly higher in gangrenous and perforated appendicitis compared with phlegmonous appendicitis and controls (p < 0.05) while MMP-2 was significantly lower in gangrenous appendicitis compared with phlegmonous appendicitis and controls. MMP-2 was also lower in perforated appendicitis when compared with controls (p < 0.01). Elevated expression of MMP-9 was demonstrated in all groups of appendicitis compared with the controls (p < 0.001).
  
  
  CONCLUSIONS
  MMP-9 is the most abundantly expressed MMP of those investigated in inflamed appendix. We postulate that a local imbalance between MMP-9 and TIMP-1 may trigger a perforation. These results suggest that MMPs might be useful as biomarkers of appendices prone to perforation.
authors.affiliation: Department of Surgery, Colorectal Unit, Sahlgrenska University Hospital/Ostra, Gothenburg University, Gothenburg, Sweden. anna.solberg@surgery.gu.se
authors.forename: Anna
authors.initials: A
authors.lastname: Solberg
authors.forename: Lena
authors.initials: L
authors.lastname: Holmdahl
authors.forename: Peter
authors.initials: P
authors.lastname: Falk
authors.forename: Ingrid
authors.initials: I
authors.lastname: Palmgren
authors.forename: Marie-Louise
authors.initials: ML
authors.lastname: Ivarsson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001062:Appendectomy / Q000009:adverse effects; D001064:Appendicitis / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D001065:Appendix / Q000378:metabolism*; D004630:Emergencies; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D008875:Middle Aged; D011183:Postoperative Complications; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism*
chemical_list: D019715:Tissue Inhibitor of Metalloproteinase-1; D020782:Matrix Metalloproteinases