title: Ability of serum to decrease cellular acylCoA:cholesterol acyl transferase activity predicts cardiovascular outcomes.
abstract: BACKGROUND
  We evaluated whether cholesterol efflux activity of serum is associated with the presence of angiographic coronary artery disease (CAD) and the risk of major adverse cardiovascular events (MACE) and death.
  
  
  RESULTS
  We studied 168 men undergoing coronary angiography. Cholesterol efflux activity was measured in vitro by incubation of patient serum with human skin fibroblasts and defined as the ability of serum to decrease the pool of cholesterol available for esterification by the acylCoA:cholesterol acyl transferase (ACAT) reaction. We evaluated whether this activity was associated with the presence of CAD and the risk of MACE and death during a 4.5-year follow-up. Serum-induced changes in ACAT activity did not correlate with HDL levels or the presence of CAD. Patients in the highest tertile of change in ACAT activity had a significantly higher risk for MACE (HR, 2.15; 95% CI, 1.36 to 3.39; P=0.001) and death (HR, 2.23; 95% CI, 1.17 to 4.26; P=0.01). These correlations were independent of other risk markers including LDL, HDL, and C-reactive protein levels.
  
  
  CONCLUSIONS
  Serum-induced depletion of cellular cholesterol available for esterification by ACAT was a strong, independent predictor of MACE and death. We speculate that the ability of serum to decrease ACAT activity depends on ATP binding cassette transporter A1 (ABCA1)-mediated efflux. Furthermore, serum samples that induce larger changes in ACAT activity contain increased levels of HDL particles that preferentially interact with ABCA1 and that these particles accumulate in the serum of patients because of low activity of ABCA1 in vivo preventing or limiting the extent of apoA-I lipidation.
authors.affiliation: Miller School of Medicine, University of Miami, Miami, FL 33138, USA.
authors.forename: Julio A
authors.initials: JA
authors.lastname: Chirinos
authors.forename: Juan P
authors.initials: JP
authors.lastname: Zambrano
authors.forename: Simon
authors.initials: S
authors.lastname: Chakko
authors.forename: Alan
authors.initials: A
authors.lastname: Schob
authors.forename: Ronald B
authors.initials: RB
authors.lastname: Goldberg
authors.forename: Guido
authors.initials: G
authors.lastname: Perez
authors.forename: Armando J
authors.initials: AJ
authors.lastname: Mendez
mesh_terms: D000368:Aged; D002318:Cardiovascular Diseases / Q000097:blood* / Q000453:epidemiology / Q000401:mortality; D002784:Cholesterol / Q000097:blood*; D017023:Coronary Angiography / Q000379:methods*; D005006:Ethnicity; D006801:Humans; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D002785:Sterol O-Acyltransferase / Q000378:metabolism*; D016019:Survival Analysis; D013631:Tangier Disease / Q000097:blood / Q000378:metabolism; D016896:Treatment Outcome
chemical_list: D008055:Lipids; D002784:Cholesterol; D002785:Sterol O-Acyltransferase; C493492:sterol O-acyltransferase 1