The physicochemical basis of cholesterol gallstone formation in man

Relationship of biliary phospholipid and cholesterol concentrations to the occurrence and dissolution of human gallstones

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A model for gallbladder function and cholesterol gallstone formation

An analysis of fluid mechanics and diffusion in the gallbladder predicts that there is a thin layer of high bile-constituent concentration near the gallbladder wall. Cholesterol may precipitate in this layer, even when the average cholesterol concentration in the gallbladder is below saturation. The amount precipitated increases with time, with increased average cholesterol concentration, and with decreased average lecithin concentration. If the gallbladder does not empty completely, the precipitated cholesterol particles may grow over many cycles of gall bladder filling and emptying. The analysis explains why cholesterol-gallstone formation is not correlated with bile-constituent concentration alone, why a flaccid, noncontractile, gallbladder has a greater chance of forming gallstones, why small stones are frequently found near the gallbladder wall, and why stones may be found in only one limb of a double gallbladder.

Effects of controlled interruption of the enterohepatic circulation of bile salts by biliary diversion and by ileal resection on bile salt secretion, synthesis, and pool size in the rhesus monkey

The effects of controlled interruption of the enterohepatic circulation (EHC) of bile salts by biliary diversion on bile volume, bile salt secretion and synthesis rates, bile salt pool size, and the relationship to fecal fat excretion were studied in 16 rhesus monkeys. Bile from a chronic bile fistula was returned to the intestine through an electronic stream-splitter which, by diverting different percentages of bile to a collecting system, provided graded and controlled interruption of the EHC. The increase in hepatic bile salt synthesis in response to interruption of the EHC was limited and reached a maximum rate at 20% interruption of the EHC. Up to this level of biliary diversion, the increased hepatic synthesis compensated for bile salt loss so that bile salt secretion and pool size were maintained at normal levels. With diversion of 33% or more, there was no further increase in hepatic bile salt synthesis to compensate for external loss, and as a result there was diminished bile salt secretion, a reduction in bile salt pool size, and steatorrhea was observed. The effects of interruption of the EHC by the streamsplitter were compared with those produced by resection of the distal one-third or two-thirds of small bowel. While ileal resection appreciably reduced bile salt secretion, the EHC was by no means abolished. Bile salt reabsorption from the residual intestine was greater after one-third than after two-thirds small bowel resection. These observations suggest that jejunal reabsorption of bile salts occurs and may well contribute to the normal EHC.

Pregnancy, cholesterol metabolism and gallstones

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