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The human gallbladder increases cholesterol solubility in bile by differential lipid absorption: A study using a new in vitro model of isolated intra‐arterially perfused gallbladder
Author(s) -
Ginanni Corradini Stefano,
Ripani Cristina,
Della Guardia Paola,
Giovannelli Luca,
Elisei Walter,
Cantafora Alfredo,
Pisanelli Massimo Codacci,
Tebala Giovanni Domenico,
Nuzzo Gennaro,
Corsi Alessandro,
Attili Adolfo Francesco,
Capocaccia Livio,
Ziparo Vincenzo
Publication year - 1998
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.510280205
Subject(s) - gallbladder , cholesterol , phosphatidylcholine , medicine , phospholipid , in vivo , bile duct , biliary tract , cystic duct , chemistry , endocrinology , biology , biochemistry , microbiology and biotechnology , membrane
In this study, we first developed and validated a new in vitro isolated, intra‐arterially perfused, gallbladder model and then applied the method to investigate the absorption of biliary lipids by the gallbladder wall and the effect of this process on the composition of human bile. Oxygenated and glucose‐added buffer was perfused through the cystic artery to maintain organ viability. A standard pooled natural bile, radiolabeled with H 3 ‐cholesterol and C 14 ‐palmitoyl‐linoleoyl‐phosphatidylcholine, was instilled in the lumen via a cystic duct catheter. Changes in bile volume and lipid concentrations were monitored at time intervals to evaluate the disappearance of lipids from bile caused by gallbladder absorptive function. Organ viability was demonstrated by stable lactate dehydrogenase (LDH) organ release and oxygen consumption throughout the experiments. In the pig, disappearance rates of lipids from bile were similar in vitro and in vivo, demonstrating the validity of the isolated in vitro model for functional studies. By applying our in vitro isolated preparation to the human gallbladder, we found that 23% of cholesterol and 32% of phosphatidylcholine, but only 9% of bile salts, disappeared from bile in 5 hours. As a consequence, at the end of the experiments, cholesterol ( P < .05) and phospholipid ( P < .05) molar percentages were significantly reduced, while the bile salt ( P < .05) molar percentage was significantly increased with respect to values at the beginning of the studies. Our findings are of pathophysiological relevance and support the concept that the human gallbladder modifies the relative composition of biliary lipids in such a way as to increase cholesterol solubility in bile.