title: Matrix metalloproteinase-9 genotype influences large artery stiffness through effects on aortic gene and protein expression.
abstract: OBJECTIVE
  Because large artery stiffening contributes to myocardial ischemia, its determinants are of relevance as potential risk markers. This study examined whether matrix metalloproteinase (MMP)-9 (gelatinase B) genotype is associated with large artery stiffening and aortic MMP-9 gene and protein expression.
  
  
  RESULTS
  MMP-9 genotype (C-1562T promoter polymorphism) was determined in 84 patients (73 male) with angiographically defined coronary artery disease (CAD). Carotid applanation tonometry was used to assess central blood pressures and, with Doppler velocimetry, to assess aortic stiffness (input and characteristic impedance). Gene expression real-time polymerase chain reaction (RT-PCR) and protein levels (Western blotting) were assessed in relation to genotype in aortic samples from a separate population. T-allele carriers (C/T and T/T) had stiffer large arteries (higher input and characteristic impedance) and higher carotid pulse and systolic blood pressure (all P<0.05) than C/C homozygotes. In aortic samples, gene expression was 5-fold higher and active protein levels were >2-fold higher in T-allele carriers.
  
  
  CONCLUSIONS
  Because the T allele was associated with greater MMP-9 mRNA and protein levels, the greater large artery stiffness in T-allele carriers may be secondary to excessive degradation of the arterial elastic matrix. The consequent higher pulse pressure may increase susceptibility to myocardial ischemia.
authors.affiliation: Alfred and Baker Medical Unit, Baker Medical Research Institute, University of Melbourne, Victoria, Australia.
authors.forename: Tanya L
authors.initials: TL
authors.lastname: Medley
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Cole
authors.forename: Anthony M
authors.initials: AM
authors.lastname: Dart
authors.forename: Christoph D
authors.initials: CD
authors.lastname: Gatzka
authors.forename: Bronwyn A
authors.initials: BA
authors.lastname: Kingwell
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D001011:Aorta / Q000201:enzymology / Q000473:pathology*; D001794:Blood Pressure; D009202:Cardiomyopathies / Q000201:enzymology / Q000473:pathology; D002339:Carotid Arteries / Q000473:pathology*; D017023:Coronary Angiography; D003327:Coronary Disease / Q000201:enzymology / Q000235:genetics*; D017097:Electric Impedance; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D008365:Manometry; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis; D012307:Risk Factors; D014463:Ultrasonography; D014694:Ventricular Outflow Obstruction / Q000000981:diagnostic imaging / Q000209:etiology
chemical_list: D012333:RNA, Messenger; D020780:Matrix Metalloproteinase 9