Altered Transfer of Cholesteryl Esters and Phospholipids in Plasma From Alcohol Abusers

Abstract

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.

Beyond HDL-cholesterol increase: phospholipid enrichment and shift from HDL3 to HDL2 in alcohol consumers

“…In addition, alcohol-induced phospholipid transfer protein (PLTP) activity, which shifts PL from TG-rich lipoproteins to HDL, appears to increase HDL 2b at the expense of HDL 3a (large HDL 3 ) (37). The reduction of CETP and the increase of PLTP were confirmed by another study, which also observed an increase in the net PL transfer from apoB-containing lipoproteins to HDL in alcoholics (38). However, none of these enzymes seems to be changed in moderate alcohol consumers (39)(40)(41).…”

PLTP activity decreases with weight loss

“…An increase in NEFA is also a characteristic of other conditions associated with an increase in PLTP. PLTP activity is elevated in alcoholics, who demonstrate increased NEFA concentrations, and PLTP decreases upon withdrawal (33,34). PLTP activity decreases with the administration of Acipimox, which is thought to inhibit hormone-sensitive lipase and thus decrease NEFA release from adipose tissue (35).…”

Characterization of metabolic interrelationships and in silico phenotyping of lipoprotein particles using self-organizing maps

“…Here, we focus on an extensive set of UCF-based lipoprotein data in which the apoB particles were isolated as VLDL, IDL, and LDL fractions and the HDL particles separated to HDL 2 and HDL 3 (18)(19)(20). The use of UCF is tedious and expensive and thus, most often only the total HDL fraction is physically isolated and the IDL fraction might not be separately spun.…”

“…However, the molecular composition as well as the metabolic and structural interrelationships between lipoprotein particles are often hampered due to limited measurement data available and the molecular complexity of lipoprotein metabolism. Physical isolation of lipoproteins by sequential ultracentrifugation (UCF) is common to measure plasma lipoprotein concentrations ( 17 ) but most studies are restricted regarding the analyzed subpopulations and detailed attention is rarely paid to the molecular composition of the isolated particles.Here, we focus on an extensive set of UCF-based lipoprotein data in which the apoB particles were isolated as VLDL, IDL, and LDL fractions and the HDL particles separated to HDL 2 and HDL 3 (18)(19)(20). The use of UCF is tedious and expensive and thus, most often only the total HDL fraction is physically isolated and the IDL fraction might not be separately spun.…”