Altered transfer of cholesteryl esters and phospholipids in plasma from alcohol abusers

The net mass transfer (NMT) of cholesteryl esters (CEs), triglycerides (TGs), and phospholipids (PLs) between lipoproteins was measured after incubation of fresh plasma for up to 2 hours from 18 male alcohol abusers and 17 male volunteer control subjects. In alcohol abusers the mean value of CE NMT was 3.7 nmol.mL-1.h-1 from apolipoprotein B-containing lipoproteins (apoB-containing lipoproteins) to HDL and in control subjects 8.7 nmol.mL-1.h-1 from HDL to apoB-containing lipoproteins. The NMT of PL was higher in alcohol abusers than in control subjects (35.0 vs 11.6 nmol.mL-1.h-1 from apoB-containing lipoproteins to HDL, respectively), and plasma PL transfer protein (TP) activity was 33% higher (P < .05) in alcohol abusers than in control subjects. The lack of correlation between the NMTs and CETP and PLTP activities suggests that the NMT could more closely reflect the role of lipoprotein properties in reverse cholesterol transport in vivo, whereas in vitro activities reflect the total capacity of transfer but not its direction. The rate of CE NMT from HDL to apoB-containing lipoproteins was dependent on the VLDL TG concentration. Moreover, at low VLDL TG levels, the increased HDL cholesterol concentration in alcohol abusers reversed the direction of CE NMT. This situation could be reconstructed in the plasma of control subjects by adding autologous HDL or VLDL to mimic the lipoprotein profiles of the alcohol abusers. Addition of VLDL enhanced the CE NMT from HDL to apoB-containing lipoproteins, whereas addition of HDL had an opposite effect, and at higher HDL levels, even reversed the direction of CE NMT. In conclusion, the NMT of CE and PL in alcohol abusers differs from that in control subjects. The concentrations of HDL and VLDL seem to be the major determinants of the direction of CE NMT in alcohol abusers.