title: Pregnancy-associated plasma protein A as a marker of acute coronary syndromes.
abstract: BACKGROUND
  Circulating markers indicating the instability of atherosclerotic plaques could have diagnostic value in unstable angina or acute myocardial infarction. We evaluated pregnancy-associated plasma protein A (PAPP-A), a potentially proatherosclerotic metalloproteinase, as a marker of acute coronary syndromes.
  
  
  METHODS
  We examined the level of expression of PAPP-A in eight culprit unstable coronary plaques and four stable plaques from eight patients who had died suddenly of cardiac causes. We also measured circulating levels of PAPP-A, C-reactive protein, and insulin-like growth factor I (IGF-I) in 17 patients with acute myocardial infarction, 20 with unstable angina, 19 with stable angina, and 13 controls without atherosclerosis.
  
  
  RESULTS
  PAPP-A was abundantly expressed in plaque cells and extracellular matrix of ruptured and eroded unstable plaques, but not in stable plaques. Circulating PAPP-A levels were significantly higher in patients with unstable angina or acute myocardial infarction than in patients with stable angina and controls (P<0.001). A PAPP-A threshold value of 10 mlU per liter identified patients who had acute coronary syndromes with a sensitivity of 89.2 percent and a specificity of 81.3 percent. PAPP-A levels correlated with levels of C-reactive protein and free IGF-I, but not with markers of myocardial injury (troponin I and the MB isoform of creatine kinase).
  
  
  CONCLUSIONS
  PAPP-A is present in unstable plaques, and circulating levels are elevated in acute coronary syndromes; these increased levels may reflect the instability of atherosclerotic plaques. PAPP-A is a new candidate marker of unstable angina and acute myocardial infarction.
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic and Foundation, Rochester, Minn 55905, USA.
authors.forename: A
authors.initials: A
authors.lastname: Bayes-Genis
authors.forename: C A
authors.initials: CA
authors.lastname: Conover
authors.forename: M T
authors.initials: MT
authors.lastname: Overgaard
authors.forename: K R
authors.initials: KR
authors.lastname: Bailey
authors.forename: M
authors.initials: M
authors.lastname: Christiansen
authors.forename: D R
authors.initials: DR
authors.lastname: Holmes
authors.forename: R
authors.initials: R
authors.lastname: Virmani
authors.forename: C
authors.initials: C
authors.lastname: Oxvig
authors.forename: R S
authors.initials: RS
authors.lastname: Schwartz
mesh_terms: D000368:Aged; D000787:Angina Pectoris / Q000097:blood; D000789:Angina, Unstable / Q000097:blood* / Q000175:diagnosis; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D016022:Case-Control Studies; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000473:pathology; D003331:Coronary Vessels / Q000473:pathology; D016757:Death, Sudden, Cardiac; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000175:diagnosis; D009206:Myocardium / Q000473:pathology; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis*; D011379:Prognosis; D012044:Regression Analysis
chemical_list: D015415:Biomarkers; D007334:Insulin-Like Growth Factor I; D002097:C-Reactive Protein; D011266:Pregnancy-Associated Plasma Protein-A