LCAT-dependent conversion rate is a determinant of plasma preβ1-HDL concentration in healthy Japanese

Abstract Background Preβ1-HDL acts as a primary acceptor of cellular cholesterol. Preβ1-HDL is converted into α-migrating high-density lipoprotein (HDL) by lecithin/cholesterol acyltransferase (LCAT). We examined whether the LCAT-dependent conversion rate of preβ1-HDL is a determinant of the plasma preβ1-HDL concentration in healthy Japanese. Methods We measured the conversion half time (CHT preβ1 ), the time required for 50% of baseline preβ1-HDL to be changed into α-migrating HDL by LCAT, in 100 healthy Japanese (47 men, 53 women, 22–88 years). Results Preβ1-HDL concentration, as determined by immunoassay, was significantly lower in younger women ( n =24) than in older women (≥50 years, n =29) (16.8±3.3 vs. 21.7±8.0 mg/l apolipoprotein AI (apoAI), p n =24) and older ( n =23) men (21.2±6.8 vs. 22.5±6.6 mg/l apoAI). The mean CHT preβ1 for all subjects was 47.4±13.0 min, and was not influenced by gender or age. Preβ1-HDL concentration was positively correlated with CHT preβ1 in both men and women, suggesting that high preβ1-HDL levels may reflect delayed conversion of preβ1-HDL. Conclusion LCAT-dependent conversion rate is a determinant of plasma preβ1-HDL concentration in healthy Japanese. We speculate that preβ1-HDL concentration may be used as a metabolic marker for HDL maturation.