devazepide and Cholelithiasis

A defect in gallbladder contraction function plays a key role in the pathogenesis of gallstones. The cholecystokinin-1 receptor (CCK-1R) antagonists have been extensively investigated for their therapeutic effects on gastrointestinal and metabolic diseases in animal studies and clinical trials. However, it is still unknown whether they have a potential effect on gallstone formation.. To study whether the CCK-1R antagonists enhance cholelithogenesis, we investigated cholesterol crystallization, gallstone formation, hepatic lipid secretion, gallbladder emptying function and intestinal cholesterol absorption in male C57BL/6J mice treated by gavage with devazepide (4 mg/day/kg) or vehicle (as controls) twice per day and fed the lithogenic diet for 21 days.. During 21 days of feeding, oral administration of devazepide significantly accelerated cholesterol crystallization and crystal growth to microlithiasis, with 40% of mice forming gallstones, whereas only agglomerated cholesterol monohydrate crystals were found in mice receiving vehicle. Compared to the vehicle group, fasting and postprandial residual gallbladder volumes in response to the high-fat meal were significantly larger in the devazepide group during cholelithogenesis, showing reduced gallbladder emptying and bile stasis. Moreover, devazepide significantly increased hepatic secretion of biliary cholesterol, but not phospholipids or bile salts. The percentage of intestinal cholesterol absorption was higher in devazepide-treated mice, increasing the bioavailability of chylomicron-derived cholesterol in the liver for biliary hypersecretion into bile. These abnormalities induced supersaturated bile and rapid cholesterol crystallization.. The potent CCK-1R antagonist devazepide increases susceptibility to gallstone formation by impairing gallbladder emptying function, disrupting biliary cholesterol metabolism and enhancing intestinal cholesterol absorption in mice.

Topics: Animals; Bile Acids and Salts; Cholelithiasis; Cholesterol; Devazepide; Gallbladder; Gallbladder Emptying; Hormone Antagonists; Intestinal Mucosa; Intestines; Male; Mice; Mice, Inbred C57BL; Receptor, Cholecystokinin A

Human gallbladders with cholesterol stones exhibit impaired muscle contraction induced by agonists that act on transmembrane receptors, increased membrane cholesterol content, and abnormal cholesterol-to-phospholipid ratio compared with those with pigment stones. The present study was designed to investigate the functions of the CCK receptor of gallbladder muscle membranes by radioreceptor assay and cross-linking. 125I-labeled CCK-8 binding was time-dependent, competitive, and specific. Scatchard analysis showed that the maximum specific binding (Bmax) was significantly decreased in cholesterol compared with pigment stone gallbladders (0.18 +/- 0. 07 vs. 0.38 +/- 0.05 pmol/mg protein, P < 0.05). In contrast, the affinity for CCK was higher in cholesterol than pigment stone gallbladders (0.18 +/- 0.06 vs. 1.2 +/- 0.23 nM). Similar results were observed in binding studies with the CCK-A receptor antagonist [3H]L-364,718. Cross-linking and saturation binding studies also showed significantly less CCK binding in gallbladders with cholesterol stones. These abnormalities were reversible after incubation with cholesterol-free liposomes. The Bmax increased (P < 0.01) and the dissociation constant decreased (P < 0.001) after incubation with cholesterol-free liposomes. In conclusion, human gallbladders with cholesterol stones have impaired CCK receptor binding compared with those with pigment stones. These changes are reversed by removal of the excess membrane cholesterol. These receptor alterations may contribute to the defective contractility of the gallbladder muscle in patients with cholesterol stones.

Topics: Bile Pigments; Cell Membrane; Cholelithiasis; Cholesterol; Cross-Linking Reagents; Devazepide; Gallbladder; Hormone Antagonists; Humans; In Vitro Techniques; Liposomes; Muscle, Smooth; Receptor, Cholecystokinin A; Receptors, Cholecystokinin; Sincalide

Although gallbladder stasis exists in most patients with cholesterol gallstones, it is unknown whether stasis is a causative factor of gallstone disease or merely a consequence of it. We studied the impact of sustained gallbladder stasis induced by a cholecystokinin (CCK)-A receptor antagonist (MK-329) on gallstone formation in ground squirrels fed either a trace or a high-cholesterol diet. MK-329 markedly inhibited gallbladder contraction in vitro in response to CCK (at EC100, control: 3.6 +/- 0.5 vs. MK-329: 1.1 +/- 0.3 g; P < .05) and increased gallbladder fasting volume in vivo (control: 462 +/- 66 vs. MK-329: 1,004 +/- 121 microL; P < .05). Whereas the high-cholesterol diet alone (1%-cholesterol diet + placebo) increased the cholesterol saturation index (CSI) in control animals (trace-cholesterol diet + placebo), MK-329 significantly (P < .05) decreased the CSI in both hepatic and gallbladder bile in animals on the trace-(trace-cholesterol diet + MK-329) as well as on the high-cholesterol diets (1%-cholesterol diet + MK-329). The mucin content of the mucus layer on the epithelial surface of the gallbladder wall more than doubled (P < .05) with the high-cholesterol diet; adding MK-329 to the latter group produced a further 82% increase (P < .05). The cholesterol diet + MK-329 group had the highest (100%) incidence of cholesterol crystals that were evident in fresh gallbladder bile, coincident with a shortened nucleation time (2.5 +/- 0.6 days; P < .05 vs. the cholesterol diet + placebo group, 5.8 +/- 1.0 days or the other 2 groups, >21 days). Bile from animals on the trace-cholesterol diet, whether or not receiving MK-329, lacked crystals in bile and exhibited a normal nucleation time (>21 days). Thus, stasis per se may lower the CSI, but its detrimental effect on the gallbladder predominates locally, and so accelerates cholesterol crystal formation in this model.

Topics: Animals; Benzodiazepinones; Cholelithiasis; Cholesterol; Devazepide; Mucins; Sciuridae