title: Effects of age on plasma matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs).
abstract: BACKGROUND
  The mechanisms causing age-dependent changes in left ventricular (LV) structure and function are not completely understood. Matrix metalloproteinase (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) constitute one important proteolytic pathway affecting LV remodeling. However, whether these determinants of extracellular matrix (ECM) composition change as a function of age has not been examined in an aging population free of clinically significant cardiovascular disease.
  
  
  RESULTS
  Subjects (n = 77, age 20-90 years) with no evidence of cardiovascular disease underwent echocardiography and measurement of plasma MMP-2, 7, 8, and 9 and TIMP-1, 2, and 4 (enzyme-linked immunosorbent assay). As subject age increased, volume/mass ratio decreased and mitral E/A ratio decreased. As subject age increased, MMP-2 increased (from 1188 +/- 99 ng/mL to 1507 +/- 76 ng/mL), MMP-7 increased (from 1.2 +/- 0.1 ng/mL to 3.1 +/- 0.6 ng/mL), MMP-9 decreased (from 29 +/- 7 ng/mL to 8 +/- 2 ng/mL), and TIMP-1, 2, and 4 increased (from 728 +/- 46 ng/mL to 1093 +/- 73 ng/mL, from 34 +/- 5 ng/mL to 53 +/- 6 ng/mL, and from 1.26 +/- 0.22 ng/mL to 2.34 +/- 0.30 ng/mL, respectively) (all P < .05). There were significant correlations between decreased LV volume/mass and E/A ratio and increased MMP-7 and TIMP-1 and 4.
  
  
  CONCLUSIONS
  MMPs and TIMPs changed as a function of age in the absence of clinically significant cardiovascular disease. These age-dependent alterations in MMP and TIMP profiles favor ECM accumulation and were associated with concentric remodeling and decreased LV diastolic function. Because of these age-dependent changes in this proteolytic system, the superimposition of disease processes such as myocardial infarction or hypertensive heart disease in the older subject may result in different myocardial ECM remodeling than that seen in a younger subject.
authors.affiliation: Division of Cardiology, Department of Medicine, Medical University of South Carolina and RHJ Department of Veterans Affairs Medical Center, Charleston, South Carolina 29425, USA.
authors.forename: D Dirk
authors.initials: DD
authors.lastname: Bonnema
authors.forename: Carson S
authors.initials: CS
authors.lastname: Webb
authors.forename: Weems R
authors.initials: WR
authors.lastname: Pennington
authors.forename: Robert E
authors.initials: RE
authors.lastname: Stroud
authors.forename: Amy E
authors.initials: AE
authors.lastname: Leonardi
authors.forename: Leslie L
authors.initials: LL
authors.lastname: Clark
authors.forename: Catherine D
authors.initials: CD
authors.lastname: McClure
authors.forename: Laura
authors.initials: L
authors.lastname: Finklea
authors.forename: Francis G
authors.initials: FG
authors.lastname: Spinale
authors.forename: Michael R
authors.initials: MR
authors.lastname: Zile
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood* / Q000378:metabolism; D001794:Blood Pressure; D004452:Echocardiography; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D020783:Matrix Metalloproteinase 7 / Q000097:blood; D020782:Matrix Metalloproteinases / Q000097:blood*; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging; D009206:Myocardium / Q000378:metabolism; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000097:blood; D019714:Tissue Inhibitor of Metalloproteinases / Q000097:blood*; D016277:Ventricular Function, Left; D000097792:Tissue Inhibitor of Metalloproteinase-4