Gallstone cholesterol content is related to apolipoprotein E polymorphism.
BACKGROUND
The genetically determined phenotypes of apolipoprotein E are related to variations in lipoprotein levels and in the enterohepatic metabolism of cholesterol and bile acids. The present study was designed to elucidate the role of apolipoprotein E polymorphism in gallstone formation.


METHODS
Apolipoprotein E phenotype was determined in 169 consecutive cholecystectomy patients and in 200 controls. The cholesterol content of the gallstones (n = 169), the presence of cholesterol monohydrate crystals of fresh gallbladder bile (n = 142), and the nucleation time (n = 35) were also analyzed.


RESULTS
The median cholesterol content of the gallstones was higher in the apolipoprotein E4 category (phenotypes E4/4 and E4/3, 97%) than in the E3 (E3/3, 78%) and E2 patients (E2/2 and E2/3, 76%, P = 0.0003). In E4 patients, cholesterol crystals were found immediately after surgery in 27 of 40 (68%), whereas in E3 and E2 groups in 36 of 88 (41%), and 4 of 14 (29%) of the patients (P = 0.0001). The median nucleation time in E4 patients (2.5 days) was shorter than in patients with E3 (5.5 days) or E2 (6.0 days) (P = 0.0016).


CONCLUSIONS
These data indicate that apolipoprotein E polymorphism affects cholesterol content of cholelithiasis. We suggest that this phenomenon is mediated by the altered formation of cholesterol monohydrate crystals in different apolipoprotein E phenotypes.
Juvonen
T
T
Department of Surgery, University of Oulu, Finland.
Kervinen
K
K
Kairaluoma
M I
MI
Lajunen
L H
LH
Kesäniemi
Y A
YA
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D001057:Apolipoproteins E / Q000032:analysis / Q000235:genetics*; D001646:Bile / Q000737:chemistry; D002769:Cholelithiasis / Q000737:chemistry* / Q000235:genetics; D002784:Cholesterol / Q000032:analysis*; D003460:Crystallization; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011110:Polymorphism, Genetic
D001057:Apolipoproteins E; D002784:Cholesterol