Plasma preβ1-HDL level is elevated in unstable angina pectoris

Preβ1-HDL, a minor HDL subfraction consisting of apolipoprotein A-I (apoA-I), phospholipids and unesterified cholesterol, plays an important role in reverse cholesterol transport. Plasma preβ1-HDL levels have been reported to be increased in patients with coronary artery disease (CAD) and dyslipidemia. To clarify the clinical significance of measuring plasma preβ1-HDL levels, we examined those levels in 112 patients with CAD, consisting of 76 patients with stable CAD (sCAD) and 36 patients with unstable angina pectoris (uAP), and in 30 patients without CAD as controls. The preβ1-HDL levels were determined by immunoassay using a specific monoclonal antibody (Mab55201) that we established earlier. The mean preβ1-HDL level in the CAD patients was significantly higher than the level in the controls (34.8 ± 12.9 mg/L vs. 26.6 ± 6.9 mg/L, p < 0.001). In addition, the mean preβ1-HDL level was markedly higher in the uAP subgroup than in the sCAD subgroup (43.1 ± 11.5 mg/L vs. 30.9 ± 11.7 mg/L, p < 0.0001). These tendencies remained even after excluding dyslipidemic subjects.These results suggest that elevation of the plasma preβ1-HDL level is associated with the atherosclerotic phase of CAD and may be useful for identifying patients with uAP.