Converting gallbladder absorption to secretion: The role of intracellular calcium

Gallbladder disease in Shetland Sheepdogs: 38 cases (1995–2005)

“…Use of research models confirms that the gallbladder epithelium plays a dominant role in biliary sludge formation and that reduced gallbladder motility, other causes of bile stasis, or enhanced gallbladder water absorption augment biliary sludge formation. [11][12][13]25,26 However, microlithiasis in canine gallbladder bile differs from the syndrome described in humans and the classic prairie dog model of cholelithiasis. In dogs, gallbladder microlithiasis involves bilirubinate pigments complexed with calcium carbonate (termed pigment choleliths) and has been induced in healthy dogs fed a protein-restricted, methionine-deficient, highcarbohydrate diet.…”

“…In humans, gallbladder sludge is described as microlithiasis and is composed of a complex mixture of cholesterol crystals, precipitated bile pigments, mucin, and bile salts. 5,[10][11][12]25,26 As such, gallbladder sludge is recognized as an early and reversible phase of cholelith formation. Use of research models confirms that the gallbladder epithelium plays a dominant role in biliary sludge formation and that reduced gallbladder motility, other causes of bile stasis, or enhanced gallbladder water absorption augment biliary sludge formation.…”

Gallbladder mucocele in dogs: 30 cases (2000–2002)

“…Increased mucus secretion from the canine gallbladder epithelium has been documented with exposure to bile salts. 13,14 Factors that promote biliary stasis or increase the concentration of bile salts within the gallbladder lumen (such as increased water absorption across the gallbladder mucosa) increase the exposure of the gallbladder mucosa to bile salts 15 and could cause the formation of gallbladder mucocele. A primary role for the gallbladder mucosa in the formation of biliary sludge, a mobile mixture of cholesterol crystals, precipitated bile pigments, and bile salts, is well documented in humans.…”

“…A primary role for the gallbladder mucosa in the formation of biliary sludge, a mobile mixture of cholesterol crystals, precipitated bile pigments, and bile salts, is well documented in humans. 16,17 Decreased gallbladder motility, biliary stasis, and altered absorption of water from the gallbladder lumen are predisposing factors to the formation of biliary sludge, 15,17 and it is possible that biliary sludge is a precipitating factor in the formation of canine gallbladder mucoceles. The luminal concentrations of mucin and phospholipids in the gallbladder are the primary determinants of bile viscosity in humans with gallstones, 18 and it is possible that alterations in phospholipid concentrations may also be a precipitating factor in the formation of canine gallbladder mucoce-les.…”

The role of biliary calcium in gallstone pathogenesis

“…The role of intra-and extracellular calcium in the conversion of gallbladder absorption to secretion during cholesterol gallstone formation in the prairie dog was studied using the calcium ionophore A23187 (71). Sodium, chloride, and water fluxes were measured in the Ussing chamber with varying concentrations of calcium (5-10 mM) in the mucosal bathing solution and in the presence and absence of A23187.…”