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 afte r incubation of fresh plasma for up to 2 hours from 18 male alcohol ab users and 17 male volunteer control subjects. In alcohol abusers the m ean value of CE NMT was 3.7 nmol.mL(-1).h(-1) from apolipoprotein B-co ntaining lipoproteins (apoB-containing lipoproteins) to HDL and in con trol subjects 8.7 nmol.mL(-1).h(-1) from HDL to apoB-containing lipopr oteins. The NMT of PL was higher in alcohol abusers than in control su bjects (35.0 vs 11.6 nmol.mL(-1).h(-1) from apoB-containing lipoprotei ns to HDL, respectively), and plasma PL transfer protein (TP) activity was 33% higher (P<.05) in alcohol abusers than in control subjects. T he lack of correlation between the NMTs and CETP and PLTP activities s uggests that the NMT could more closely reflect the role of lipoprotei n properties in reverse cholesterol transport in vivo, whereas in vitr o activities reflect the total capacity of transfer but not its direct ion. The rate of CE NMT from HDL to apoB-containing lipoproteins was d ependent on the VLDL TG concentration. Moreover, at low VLDL TG levels , the increased HDL cholesterol concentration in alcohol abusers rever sed the direction of CE NMT. This situation could be reconstructed in the plasma of control subjects by adding autologous HDL or VLDL to mim ic the lipoprotein profiles of the alcohol abusers. Addition of VLDL e nhanced the CE NMT from HDL to apoB-containing lipoproteins, whereas a ddition 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 concentr ations of HDL and VLDL seem to be the major determinants of the direct ion of CE NMT in alcohol abusers.