To determine the association of serum
apolipoprotein (
apo) A-I and B concentrations, and
paraoxonase (PON)
high-density lipoprotein (HDL) associated
enzyme activity with angiographically determined
coronary artery disease (CAD) in Iranian diabetic and non-diabetic CAD patients and non-diabetic control subjects, 251 subjects aged 30-70 years, who underwent their first coronary angiography were matched and randomly assigned into three groups: CAD(+)DM(+), CAD(+)DM(-), and CAD(-)DM(-) (control).
Stenosis of > or =50% in one or more coronary arteries was classified as CAD(+). CAD(-) was defined as a maximum
stenosis of 10% in any coronary artery. Fasting serum concentrations of
cholesterol (TC),
triglycerides (TGs),
LDL-C, HDL-C,
apo A-I/B and PON activity were determined.
Apolipoprotein concentrations were measured in a fasting serum sample by immunoturbidometric assay and
paraoxonase/
arylesterase activities by spectrophotometric assay of
p-nitrophenol/
phenol production following addition of
paraoxon/
phenylacetate. Information concerning non-
lipid risk factors were collected by questionnaires. No significant difference was observed in HDL-C,
LDL-C,
apo A-I, and PON/
arylesterase activity between the study groups. The values of TC (213+/-38 vs 196+/-45, P<0.05), TGs (209+/-187 vs 151+/-113, P<0.01),
apo B (99+/-22 vs 96+/-24, P<0.0001), TC/HDL-C (4.8+/-1.5 vs 4.0+/-1.3, P<0.001) and
LDL-C/HDL-C (2.9+/-1.1 vs 2.4+/-1.1, P<0.05) were higher and
apo A-I/B (1.7+/-0.4 vs 2.0+/-0.6, P<0.01) was lower in CAD(+)DM(+) patients than in control subjects. In CAD(+)DM(-) group, only the level of
apo B (96+/-24 vs 85+/-18, P<0.01), and the ratio of
apo A-I/B (1.8+/-0.4 vs 2.0+/-0.6, P<0.01), were significantly higher than those of control group. On multiple logistic regression analysis, the best markers for discrimination between CAD(+) groups and CAD(-) control subjects were the ratio of
apo A-I/B in diabetic and
apo B in non-diabetic patients. The results suggest that in Iranian diabetic and non-diabetic patients with CAD the concentration of
apolipoproteins are better markers than traditional
lipid parameters in discriminating between CAD(+) and CAD(-) subjects. Lack of significant difference in PON activity between CAD patients and CAD(-) controls supports the concept of interethnic variability in PON polymorphism and unimodal distribution of its activity in non-Europid populations observed in other studies.