Effect of apolipoprotein E polymorphism on bile lipid composition and the formation of cholesterol gallstone.
OBJECTIVE
It remains a matter of controversy whether possession of the apolipoprotein E4 (apoE4) allele is a genetic risk factor for the formation of cholesterol gallstones. The aim of the present study was to test this hypothesis by investigating the effect of apoE4 on bile lipid composition in normal subjects and in patients with cholesterol gallstones and to evaluate the distributions of apoE alleles in these two groups.


METHODS
The study population consisted of 79 patients who underwent open or laparoscopic cholecystectomy for symptomatic cholesterol gallstone disease. The control group (n = 53) included 11 patients with benign gallbladder polyps and 42 normal subjects acting as donors in living donor liver transplantation. The apoE genotypes were assessed by dot blot hybridization with digoxigenin-labeled probes. Bile lipid composition was determined by enzymatic assays and high performance liquid chromatography.


RESULTS
Bile lipid composition and cholesterol saturation index (CSI) were similar in the control subjects harboring the apoE4 allele and those without apoE4 (mean CSI, 85.9% and 72.2%, respectively, p = 0.69). Likewise, in the cholesterol gallstone patients, bile lipid composition and CSI were similar in the patients with and without apoE4 allele (mean CSI, 134.9% vs 152.2%, p = 0.6). Furthermore, the prevalence of the apoE4 allele was similar in the patients with cholesterol gallstones and in the control group (8.5% vs 7.6%, p = 0.46, OR = 0.88; 95% CI = 0.64-1.22).


CONCLUSIONS
The apoE4 allele is not a contributory factor to cholesterol gallstone formation, at least in the Japanese population.
Hasegawa
Kiyoshi
K
Division of Hepato-Biliary-Pancreatic Surgery, Department of Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
Terada
Sachiyo
S
Kubota
Keiichi
K
Itakura
Hiroshige
H
Imamura
Hiroshi
H
Ohnishi
Shin
S
Aoki
Taku
T
Ijichi
Masayoshi
M
Saiura
Akio
A
Makuuchi
Masatoshi
M
D000328:Adult; D000483:Alleles; D001057:Apolipoproteins E / Q000235:genetics*; D001646:Bile / Q000737:chemistry*; D001647:Bile Acids and Salts / Q000032:analysis; D016022:Case-Control Studies; D002769:Cholelithiasis / Q000209:etiology* / Q000378:metabolism*; D002784:Cholesterol / Q000378:metabolism*; D005260:Female; D005787:Gene Frequency; D006801:Humans; D008055:Lipids / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011110:Polymorphism, Genetic
D001057:Apolipoproteins E; D001647:Bile Acids and Salts; D008055:Lipids; D002784:Cholesterol