title: High oxidized LDL and elevated plasma homocysteine contribute to the early reduction of myocardial flow reserve in healthy adults.
abstract: BACKGROUND
  Impairment of coronary blood flow reserve has been shown to be an early manifestation of atherosclerosis and coronary artery disease (CAD). We studied more closely the contribution of various risk factors on early deterioration of coronary function.
  
  
  METHODS
  Fifty-one young, apparently healthy adults, with normal or mildly elevated serum cholesterol levels but without other major risk factors for CAD, such as diabetes or hypertension, underwent positron emission tomography (PET) studies. Coronary flow reserve (CFR) was measured using O15-water. In addition to the classical risk factors, the role of several new risk indicators, such as low-density lipoprotein (LDL) oxidation, infection (Chlamydia pneumoniae antibodies), and inflammation parameters (adhesion molecules, ICAM, VCAM, selectin, and C-reactive protein), homocysteine and body iron stores were investigated.
  
  
  RESULTS
  Elevated lipid and lipoprotein levels were not associated with reduced coronary reactivity. However, high autoantibody titers against oxidized LDL (oxLDL) were associated with 21% lower CFR than low oxLDL (P < 0.05). Furthermore, high homocysteine levels predicted low CFR (P < 0.05). The other measured parameters, Chlamydia pneumoniae antibody levels, C-reactive protein and adhesion molecule concentrations did not associate with myocardial blood flow. In a stepwise regression model, oxLDL (P = 0.03), homocysteine (P = 0.04) and triglycerides (P = 0.018) were significant predictors of CFR.
  
  
  CONCLUSIONS
  The present study suggests an important role for oxidized LDL and plasma homocysteine on early impairment of coronary reactivity in young adults.
authors.affiliation: Department of Medicine, University of Tampere, Finland.
authors.forename: R
authors.initials: R
authors.lastname: Laaksonen
authors.forename: T
authors.initials: T
authors.lastname: Janatuinen
authors.forename: R
authors.initials: R
authors.lastname: Vesalainen
authors.forename: T
authors.initials: T
authors.lastname: Lehtimäki
authors.forename: I
authors.initials: I
authors.lastname: Elovaara
authors.forename: O
authors.initials: O
authors.lastname: Jaakkola
authors.forename: H
authors.initials: H
authors.lastname: Jokela
authors.forename: J
authors.initials: J
authors.lastname: Laakso
authors.forename: P
authors.initials: P
authors.lastname: Nuutila
authors.forename: K
authors.initials: K
authors.lastname: Punnonen
authors.forename: O
authors.initials: O
authors.lastname: Raitakari
authors.forename: P
authors.initials: P
authors.lastname: Saikku
authors.forename: K
authors.initials: K
authors.lastname: Salminen
authors.forename: J
authors.initials: J
authors.lastname: Knuuti
mesh_terms: D000241:Adenosine; D000328:Adult; D001323:Autoantibodies / Q000097:blood; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D015815:Cell Adhesion Molecules / Q000032:analysis; D023521:Chlamydophila Infections / Q000097:blood / Q000150:complications / Q000000981:diagnostic imaging; D016993:Chlamydophila pneumoniae; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D003326:Coronary Circulation; D003327:Coronary Disease / Q000097:blood / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005293:Ferritins / Q000097:blood; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008077:Lipoproteins, LDL / Q000097:blood* / Q000276:immunology; D008297:Male; D012039:Regional Blood Flow; D012307:Risk Factors; D012907:Smoking; D014055:Tomography, Emission-Computed; D014280:Triglycerides / Q000097:blood
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D015815:Cell Adhesion Molecules; D008076:Cholesterol, HDL; D008077:Lipoproteins, LDL; D014280:Triglycerides; C099252:oxidized low density lipoprotein; D006710:Homocysteine; D002097:C-Reactive Protein; D005293:Ferritins; D002784:Cholesterol; D000241:Adenosine