title: Matrix metalloproteinase and tissue inhibitor expression in atherosclerotic and nonatherosclerotic thoracic aortic aneurysms.
abstract: OBJECTIVE
  The altered expression of matrix metalloproteinases and their inhibitors influences the formation of atherosclerotic abdominal aortic aneurysms. Their association with thoracic aneurysms is less clear. This study describes the expression of metalloproteinases and their inhibitors in atherosclerotic and nonatherosclerotic thoracic aneurysms, and compares these with age-matched controls.
  
  
  METHODS
  Matrix metalloproteinase-2 and 9 activity were measured by antibody capture, and tissue inhibitor-1 and 2 levels were measured by enzyme-linked immunosorbent assay in 24 patients with atherosclerotic aneurysms and in 63 patients with nonatherosclerotic aneurysms. Gene expression was assessed with reverse transcriptase polymerase chain reaction. The results were compared with 17 controls.
  
  
  RESULTS
  Data are in nanograms per milligram of protein. Matrix metalloproteinase-2 activity was greater in controls than in the atherosclerotic and nonatherosclerotic groups (80 +/- 67 vs 49 +/- 50 and 35 +/- 44, P = .002). Matrix metalloproteinase-9 activity was greater in the atherosclerotic group than in the nonatherosclerotic group and controls (11.7 +/- 15.7 vs 2.5 +/- 2.2 and 1.7 +/- 1.9, P = .001). Tissue inhibitor-1 and 2 levels were greater in controls than in either aneurysm group (tissue inhibitor of metalloproteinase-1: 376 +/- 192 vs 234 +/- 233 and 174 +/- 148, P = .003; tissue inhibitor of metalloproteinase-2: 143 +/- 74 vs 14 +/- 13 and 27 +/- 43, P < .001). Atherosclerotic aneurysms expressed more matrix metalloproteinase mRNA than controls.
  
  
  CONCLUSIONS
  The metalloproteinase/tissue inhibitor phenotype of atherosclerotic thoracic aneurysms is similar to that of abdominal aneurysms. The diminished expression of metalloproteinases and tissue inhibitors in nonatherosclerotic thoracic aneurysms relative to aged controls may represent a loss of smooth muscle cells.
authors.affiliation: Department of Surgery, Division of Cardiothoracic Surgery, Fletcher Allen Health Care, Burlington, Vt 05401, USA. joseph.schmoker@vtmednet.org
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Schmoker
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: McPartland
authors.forename: Erika K
authors.initials: EK
authors.lastname: Fellinger
authors.forename: Jon
authors.initials: J
authors.lastname: Boyum
authors.forename: Lucy
authors.initials: L
authors.lastname: Trombley
authors.forename: Frank P
authors.initials: FP
authors.lastname: Ittleman
authors.forename: Christopher
authors.initials: C
authors.lastname: Terrien
authors.forename: Andrew
authors.initials: A
authors.lastname: Stanley
authors.forename: Alan
authors.initials: A
authors.lastname: Howard
mesh_terms: D000368:Aged; D017545:Aortic Aneurysm, Thoracic / Q000150:complications / Q000201:enzymology* / Q000235:genetics; D050197:Atherosclerosis / Q000150:complications / Q000201:enzymology* / Q000235:genetics; D005260:Female; D015870:Gene Expression; D006801:Humans; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism; D020782:Matrix Metalloproteinases / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics / Q000378:metabolism; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000235:genetics / Q000378:metabolism; D019714:Tissue Inhibitor of Metalloproteinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D019715:Tissue Inhibitor of Metalloproteinase-1; D019714:Tissue Inhibitor of Metalloproteinases; D019716:Tissue Inhibitor of Metalloproteinase-2; D020782:Matrix Metalloproteinases; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9