LCAT-Dependent Conversion of Preβ1-HDL into α-Migrating HDL is Severely Delayed in Hemodialysis Patients

Prebeta1-HDL is a minor HDL subfraction that acts as an efficient initial acceptor of cell-derived free cholesterol. During 37 degrees C incubation, plasma prebeta1-HDL decreases over time due to its conversion to alpha-migrating HDL by lecithin:cholesterol acyltransferase (LCAT). This conversion may be delayed in hemodialysis patients who have decreased LCAT activity. To clarify whether LCAT-dependent conversion of prebeta1-HDL to alpha-migrating HDL is delayed in hemodialysis patients, prebeta1-HDL concentrations were determined in 45 hemodialysis patients and 45 gender-matched control subjects before and after 37 degrees C incubation with and without the LCAT inhibitor. It was found that the baseline prebeta1-HDL concentration in hemodialysis patients was more than twice that in the controls (44.9 +/- 21.4 versus 19.8 +/- 6.7 mg/L apoAI; P or =1.03 mmol/L) and low HDL-cholesterol levels (32 +/- 32 versus 28 +/- 23% of baseline; NS). DR(prebeta1) was positively correlated with LCAT activity (r = 0.617; P < 0.001). In conclusion, the LCAT-dependent conversion of prebeta1-HDL to alpha-migrating HDL is severely delayed in hemodialysis patients. The impaired catabolism of prebeta1-HDL may accelerate atherosclerosis in hemodialysis patients.