Because remnants of
triglyceride-rich
lipoproteins (TRLP) are potentially atherogenic, the postprandial
lipoprotein metabolism was studied in 12 normocholesterolemic, normotriglyceridemic women, aged 60 +/- 2 years, with angiographically proven
coronary artery disease (CAD+;
cholesterol 5.7 +/- 0.1 (S.E.) mmol/l,
triglyceride 1.35 +/- 0.10 mmol/l) and in 12 individually matched controls, aged 59 +/- 2 years, without angiographical abnormalities (CAD-;
cholesterol 5.1 +/- 0.2 mmol/l and
triglyceride 1.16 +/- 0.13 mmol/l). Following an oral
retinyl palmitate-fat load, the CAD+ women showed a significantly higher
triglyceride response in the
chylomicron, or Sf > 1000, fraction (P < 0.05 vs. controls). Total plasma
apolipoprotein (
apo) B and
retinyl palmitate concentrations were similar in both groups. Fasting
apo B-48 levels in the d < 1.006 g/ml fraction were significantly higher in CAD+ cases (0.25 +/- 0.03 integrated optical density (iod) units) than CAD- controls (0.15 +/- 0.03; P < 0.05). Furthermore, after the fat load, a greater absolute and incremental
apo B-48 response in the
intermediate density lipoprotein (IDL) fraction (d = 1.006-1.019 g/ml) was observed in CAD+ cases (incremental area under the curve (Delta-AUC)8: 0.40 +/- 0.12 h.iod) than CAD- controls (0.01 +/- 0.06 h.iod; P = 0.01). Post-
heparin hepatic
lipase (HL) activities were higher in the CAD+ group: 422 +/- 22 mU/l vs 288 +/- 20 mU/ml in the CAD- group (P < 0.001) while
lipoprotein lipase (LPL) activities were identical. The results provide evidence that the metabolism of intestinal TRLP is significantly different in normolipidemic women with angiographically proven CAD compared with individually matched controls without
coronary disease. Fasting
apo B-48 levels in d< 1.006 g/ml fractions represent a potentially useful marker in women at risk for CAD.