title: Native matrix metalloproteinase characteristics may influence early stenosis of venous versus arterial coronary artery bypass grafting conduits.
abstract: OBJECTIVE
  Stenosis and occlusion rates of internal mammary artery (IMA) and saphenous vein (SV) coronary artery bypass grafts (CABGs) are markedly different, which result from respective disparities in vascular remodeling. Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) regulate vascular structure and may have important influence on graft patency. However, the MMP milieu and expression profile of the IMA and SV have not been contrasted. Therefore, the aim of this study was to assess and compare the native MMP systems in IMA vs SV conduits.
  
  
  METHODS
  IMA (n = 10) and SV (n = 10) specimens were obtained from patients undergoing CABG surgery. Protein levels of MMP-1, MMP-2, and MMP-9, TIMP-1, a membrane-bound MMP activator (MT1-MMP), and an extracellular MMP inducer protein (EMMPRIN) were determined by immunoblotting and quantified by densitometric analysis. MMP-2 and MMP-9 activity was determined by gelatin zymography.
  
  
  RESULTS
  MMP-2 levels were significantly higher in SV (2,218 +/- 351 pixels) vs IMA (1,012 +/- 213 pixels) specimens (mean +/- SEM]). There were no significant differences in MMP-1, MMP-9, or TIMP-1 content; however, MT1-MMP and EMMPRIN levels were significantly lower in SV (847 +/- 190 pixels, 1,742 +/- 461 pixels) vs IMA conduits (2,590 + 403 pixels, 5,606 + 678 pixels), respectively (p < 0.05). MMP-9 activity was similar while MMP-2 activity was significantly increased in SV vs IMA specimens.
  
  
  CONCLUSIONS
  SV and IMA conduits harbor the same MMP molecular constituents. However, MMP-2 levels and activity are significantly more abundant in the SV compared to the IMA. These differences may contribute to the early pathologic remodeling of the SV vs IMA conduit following CABG surgery.
authors.affiliation: Department of Surgery, Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912, USA. manstadt@mail.mcg.edu
authors.forename: Mark P
authors.initials: MP
authors.lastname: Anstadt
authors.forename: Dion L
authors.initials: DL
authors.lastname: Franga
authors.forename: Vera
authors.initials: V
authors.lastname: Portik-Dobos
authors.forename: Arjun
authors.initials: A
authors.lastname: Pennathur
authors.forename: Mary
authors.initials: M
authors.lastname: Bannan
authors.forename: Kwabena
authors.initials: K
authors.lastname: Mawulawde
authors.forename: Adviye
authors.initials: A
authors.lastname: Ergul
mesh_terms: D000368:Aged; D001026:Coronary Artery Bypass; D005260:Female; D006083:Graft Occlusion, Vascular / Q000201:enzymology / Q000209:etiology*; D006801:Humans; D008297:Male; D008323:Mammary Arteries / Q000637:transplantation*; D020782:Matrix Metalloproteinases / Q000096:biosynthesis*; D012501:Saphenous Vein / Q000637:transplantation*; D013997:Time Factors
chemical_list: D020782:Matrix Metalloproteinases