[Lipoprotein particles LpA-I, LpA-I: A-II and LpB in coronary artery disease].
BACKGROUND
High density lipoproteins are an heterogeneous population of particles. Two main subpopulations have been identified, one contains Apo A-I and Apo A-II and is denominated LpA-I:A-II and another one contains only Apo A-I and is denominated LpA-I.


OBJECTIVE
To measure the concentrations of these particles in patients with stable coronary artery disease.


METHODS
Serum lipids, A-I and B apolipoproteins, LpA-I, LpA-I:A-II and LpB particles were measured in 73 men aged 33 to 82 years with angiographically documented coronary artery disease (CAD) and 33 control subjects aged 39 to 76 years. LpA-I, LpA-I:A-II and LpB were measured by a noncompetitive enzyme linked immunoassay using previously characterized monoclonal antibodies against ApoA-I, ApoA-II and apoB.


RESULTS
Patients with CAD had significantly higher mean levels of LDL cholesterol than the control group (p = 0.038). The mean concentration of LpA-I particles in patients with CAD was significantly lower (p = 0.031) than in control subjects, while the concentration of LpA-I:A-II particles was significantly higher (p = 0.016). The percentage of coronary stenosis correlated negatively with LpA-I and positively with LpA-I:A-II. The best relative risk (RR) indicator in these patients was LDL-cholesterol. The relative risk increases 2.5 fold when LpA-I falls below the cut-off level. Likewise, the relative risk increases 3-fold when LpA-I:A-II raises over the cut-off level.


CONCLUSIONS
Our findings indicate that the quantification of LpA-I and LpA-I:A-II particles might allow a more accurate evaluation of the CAD risk than HDL cholesterol. LpA-I might represent the antiatherogenic fraction of HDL.
Calvo
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C
Departamento de Bioquímica Clínica e Inmunología, Facultad de Farmacia, Universidad de Concepción, Chile. ecalvo@udec.cl
Olmos
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A
Ulloa
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Bustos
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A
Toledo
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L
Durán
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D
Naveas
R
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001054:Apolipoproteins A / Q000097:blood*; D001055:Apolipoproteins B / Q000097:blood*; D016022:Case-Control Studies; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D003327:Coronary Disease / Q000097:blood* / Q000209:etiology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012307:Risk Factors; D018709:Statistics, Nonparametric
D001054:Apolipoproteins A; D001055:Apolipoproteins B; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL