Changes in serum apolipoprotein and lipoprotein profile after alcohol withdrawal: Effect of apolipoprotein E polymorphism

Background: Apolipoprotein (Apo) E genotype and alcohol consumption or withdrawal strongly affect lipoprotein (Lp) metabolism and, as with any genetic and environmental factors, they might interact. The aim of this study was to investigate this gene/environment interaction by analyzing the effect of the apoE genotype on the alcohol withdrawal-induced alterations in the serum Apo and Lp profile. Methods: ApoE genotypes and concentrations of serum cholesterol, triglyceride, and Lps containing apoA-I, A-II, B, E, and C-III were determined in 84 male alcohol abusers before and after 3 weeks of abstinence. Results: After withdrawal, concentrations of serum apoA-I, LpA-I, LpA-I/A-II, apoC-III, LpC-III-non-B, apoE, and LpE-non-B significantly decreased, whereas those of triglycerides and apoB increased; levels of cholesterol, LpC-III:B, and LpB:E were not affected. ANOVA shows that apoE polymorphism effects were quite similar before and after alcohol withdrawal on all serum Apos and Lps (the interaction term between withdrawal and apoE genotype was not significant). The only interaction term that was borderline significant (p less than or equal to 0.10) concerned the apoB concentration. Before withdrawal, no association between apoB level and apoE polymorphism was observed, whereas after abstinence, a borderline significant (p less than or equal to 0.10) gradient of concentration across the three groups of subjects (epsilon2 carriers < epsilon3/epsilon3 < epsilon4 carriers) was noticed. Conclusions: Alcohol abstinence causes major changes in the antiatherogenic Apos and Lps and may increase those known to be atherogenic. Heavy alcohol consumption seems to alter the effect of apoE polymorphism on apoB levels, and further investigations are needed to clarify the mechanisms involved in this phenomenon: a defect in sialylation of apoE, formation of acetaldehyde adducts on apoB, or both.