Plasma lipoproteins affect rate of cholesterol absorbed from bile by gallbladder: preliminary data.
BACKGROUND
The excessive accumulation of cholesterol absorbed from bile by the gallbladder impairs its contractility and favours gallstone formation. The total low plasma and high density lipoprotein cholesterol concentrations are associated with gallstone disease.


OBJECTIVE
To investigate the effect of plasma lipoproteins on gallbladder cholesterol and phosphatidylcholine absorption from bile and to establish whether cholesterol absorption is Brefeldin A-sensitive.


METHODS
Gallbladder mucosa lipid absorption rates were measured using: 1) in vitro isolated intra-arterially perfused pig gallbladder model with and without plasma lipoproteins perfusing the vascular tree; 2) human gallbladder fragments mounted in Ussing chambers with plasma lipoproteins at different concentrations in the serosal side; 3) pig gallbladder fragments mounted in Ussing chambers in the presence and absence of Brefeldin A.


RESULTS
Total lipoproteins and high density lipoprotein significantly increased the release of biliary cholesterol and phosphatidylcholine in plasma and significantly decreased the tissue accumulation of cholesterol absorbed from bile. The scavenger effect of plasma lipoproteins on cholesterol absorbed from bile was concentration dependent. Brefeldin A did not influence gallbladder absorption of biliary cholesterol.


CONCLUSIONS
Biliary cholesterol is absorbed by gallbladder mucosa via a Brefeldin-insensitive pathway and is removed by plasma lipoproteins.
Della Guardia
P
P
Department of Clinical Medicine, University La Sapienza, Rome, Italy.
Grossi
A
A
Elisei
W
W
Eramo
A
A
de Santis
A D
AD
Attili
A F
AF
Genco
A
A
Basso
N
N
Ginanni Corradini
S G
SG
D000042:Absorption / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001646:Bile / Q000737:chemistry / Q000378:metabolism; D020126:Brefeldin A / Q000494:pharmacology; D002769:Cholelithiasis / Q000209:etiology / Q000503:physiopathology; D002784:Cholesterol / Q000378:metabolism*; D046508:Culture Techniques; D004195:Disease Models, Animal; D005704:Gallbladder / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D008075:Lipoproteins, HDL / Q000378:metabolism* / Q000494:pharmacology; D011336:Probability; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D013045:Species Specificity
D008075:Lipoproteins, HDL; D011500:Protein Synthesis Inhibitors; D020126:Brefeldin A; D002784:Cholesterol