Effects of liraglutide on gallbladder emptying: A randomized, placebo-controlled trial in adults with overweight or obesity.

AIMS: Treatment with liraglutide 3.0 mg has been associated with gallbladder-related adverse events. To conduct a single-centre, double-blind, 12-week trial comparing the effect of 0.6 mg liraglutide and steady-state liraglutide 3.0 mg with placebo on gallbladder emptying in adults with body mass index (BMI) ≥27 kg/m2 and without diabetes. METHODS: Participants were randomized 1:1 to once-daily subcutaneous liraglutide (n = 26) or placebo (n = 26), starting at 0.6 mg with 0.6-mg weekly increments to 3.0 mg, with nutritional and physical activity counselling. A 600-kcal (23.7 g fat) liquid meal test was performed at baseline, after the first dose and after 12 weeks. The primary endpoint was the 12-week maximum postprandial gallbladder ejection fraction (GBEFmax ), measured over 240 minutes after starting the meal. RESULTS: Baseline characteristics were similar between groups (mean ± SD overall age 47.6 ± 10.0 years, BMI 32.6 ±3.4 kg/m2 , 50% women). Mean 12-week GBEFmax (treatment difference -3.7%, 95% confidence interval [CI] -13.1, 5.7) and area under the GBEF curve in the first 60 minutes (-390% × min, 95% CI -919, 140) did not differ for liraglutide 3.0 mg (n = 23) vs placebo (n = 24). The median (range) time to GBEFmax was 151 (11-240) minutes with liraglutide 3.0 mg and 77 (22-212) minutes with placebo. Similar findings were noted after the first 0.6-mg liraglutide dose. Gastrointestinal disorders, notably nausea and constipation, were the most frequently reported adverse events. CONCLUSIONS: Treatment with liraglutide did not affect the GBEFmax but appeared to prolong the time to GBEFmax .

The bile acid-sequestering resin sevelamer eliminates the acute GLP-1 stimulatory effect of endogenously released bile acids in patients with type 2 diabetes.

AIMS: Discovery of the specific bile acid receptors farnesoid X receptor (FXR) and Takeda G protein-coupled receptor 5 (TGR5) in enteroendocrine L cells has prompted research focusing on the impact of bile acids on glucagon-like peptide-1 (GLP-1) secretion and glucose metabolism. The aim of the present study was to assess the GLP-1 secretory and gluco-metabolic effects of endogenously released bile, with and without concomitant administration of the bile acid-sequestering resin, sevelamer, in patients with type 2 diabetes. MATERIALS AND METHODS: We performed a randomized, placebo-controlled, double-blinded cross-over study including 15 metformin-treated patients with type 2 diabetes. During 4 experimental study days, either sevelamer 3200 mg or placebo in combination with intravenous infusion of cholecystokinin (CCK) (0.4 pmol sulfated CCK-8/kg/min) or saline was administered in randomized order. The primary endpoint was plasma GLP-1 excursions as measured by incremental area under the curve. Secondary endpoints included plasma responses of glucose, triglycerides, insulin, CCK, fibroblast growth factor-19 and 7α-hydroxy-4-cholesten-3-one (C4). In addition, gallbladder dynamics, gastric emptying, resting energy expenditure, appetite and ad libitum food intake were assessed. RESULTS: CCK-mediated gallbladder emptying was demonstrated to elicit a significant induction of GLP-1 secretion compared to saline, whereas concomitant single-dose administration of the bile acid sequestrant sevelamer was shown to eliminate the acute bile acid-induced increase in plasma GLP-1 excursions. CONCLUSIONS: Single-dose administration of sevelamer eliminated bile acid-mediated GLP-1 secretion in patients with type 2 diabetes, which could be explained by reduced bile acid stimulation of the basolaterally localized TGR5 on enteroendocrine L cells.

Cholecystokinin secretion is suppressed by glucagon-like peptide-1: clue to the mechanism of the adverse gallbladder events of GLP-1-derived drugs.

OBJECTIVE: Recent randomized and controlled trials of drugs derived from the gut hormone glucagon-like peptide-1 (GLP-1) show that the most frequent adverse symptoms are gastrointestinal, including gallbladder-related side effects such as cholithiasis and cholecystitis. Since the gut hormone cholecystokinin (CCK) stimulates bile secretion and regulates gallbladder motility and emptying, we examined the effect of GLP-1 on the secretion of CCK in normal subjects and patients with type 1 diabetes mellitus. MATERIALS AND METHODS: Plasma was sampled from 10 healthy subjects and 10 patients with diabetes. With plasma glucose concentrations clamped between 6 and 9 nmol/l, GLP-1 or saline was infused for 240 min during and after a meal. The plasma concentrations of CCK were measured with a highly specific radioimmunoassay. RESULTS: Basal plasma concentrations of CCK were similar in the normal subjects and in the diabetes patients. During the meal, the CCK concentrations rose significantly during saline infusion, whereas the GLP-1 infusion suppressed the secretion of CCK significantly in both normal subjects and in the diabetes patients. CONCLUSIONS: The results show that GLP-1 suppresses the secretion of CCK after a meal in normal and diabetic subjects. The suppression attenuates the gallbladder contractility. Our data, therefore, offer an explanation for the increased risk of adverse gallbladder events during treatment with GLP-1-derived drugs.

Ursodeoxycholic acid protects interstitial Cajal-like cells in the gallbladder from undergoing apoptosis by inhibiting TNF-α expression.

Hypomotility is a common symptom of gallstone disease, which is accompanied by a loss of interstitial Cajal-like cells (ICLCs) in the gallbladder. Ursodeoxycholic acid (UDCA) is widely used in treating gallstone disease, and has shown anti-apoptotic and anti-inflammatory effects apart from its ability to dissolve gallstones. In this study, we investigated the anti-apoptotic and anti-inflammatory effects of UDCA on ICLCs in guinea pigs with gallstones. Guinea pigs were fed a high-cholesterol diet for 8 weeks to induce the formation of gallstones. A group of animals was administered UDCA (50 mg·kg-1·d-1, ig) simultaneously. At the end of 8 weeks, the animals were euthanized with anesthesia, cholecystectomy was performed immediately and gallbladder was collected for further analysis. We showed that in the model group the contractility of gallbladder muscle strips in response to both acetylcholine (ACh) and CCK-8 was severely impaired, which was significantly improved by UDCA administration. Furthermore, UDCA administration significantly reduced the apoptotic ratio of ICLCs, based on the observation of co-localization imaging of apoptotic cells and c-kit-positive cells. Western blotting analysis and real-time PCR results revealed that the TNF-α/Caspase8/Caspase3 pathway was suppressed in the UDCA-treated animals, confirming the anti-apoptotic effect of UDCA in the gallbladder. The H&E staining showed that UDCA administration significantly attenuated inflammatory cell infiltration in the gallbladder wall. In conclusion, UDCA can protect ICLCs in the gallbladder from undergoing apoptosis by inhibiting the TNF-α/Caspase8/caspase3 pathway.

Evaluation of anti-diabetic effect and gall bladder function with 2-thio-5-thiomethyl substituted imidazoles as TGR5 receptor agonists.

A novel series of 2-thio-5-thiomethyl substituted imidazoles was discovered to be potent TGR5 agonists that possessed glucose-lowering effects while inhibiting gall bladder emptying in mice.

The cholecystokinin-1 receptor antagonist devazepide increases cholesterol cholelithogenesis in mice.

BACKGROUND: 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. DESIGN: 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. RESULTS: 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. CONCLUSIONS: 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.

Impaired gallbladder motility and the effect of metformin therapy in patients with polycystic ovary syndrome.

OBJECTIVE: Impaired gallbladder (GB) emptying is a well-documented contributor to gallstone formation. The aim of this study was to evaluate GB motility in patients with polycystic ovary syndrome (PCOS). METHODS: The study population consisted of 36 PCOS patients and 20 healthy controls. GB volume was calculated using the ellipsoid formula (π/6 × L × D × W) after three-dimensional measurements were made by ultrasound [length (L), width (W) and depth (D)]. Following the determination of fasting GB volume (V0), patients were given a standard liquid meal. GB volume measurement was then repeated after 10, 20, 30, 40, 50, 60, 75 and 90 min. Gallbladder ejection fraction (GBEF) was calculated after each measurement. PCOS patients were re-evaluated after a 12-week course of metformin therapy at a dose of 1000 mg/day. RESULTS: Mean baseline GB volume (V0) was significantly higher in the patient group compared to the control group (27·2 ± 12·5 cm(3) vs 13·3 ± 7·0 cm(3) , P < 0·001). While baseline GBEF values were similar between groups, increases in GBEF were significantly lower in the PCOS group starting from 20 min after consumption of a standard test meal. A 12-week course of metformin therapy resulted in significant improvements in GB volume and GBEF values with a reversal of metabolic and hormonal abnormalities. CONCLUSION: For the first time in the literature, we managed to demonstrate impaired GB motility in patients with PCOS. Metformin therapy not only improves the metabolic and hormonal imbalances associated with PCOS but also has a positive influence on GB motility.

Gallbladder emptying in patients with major depression: a case series.

INTRODUCTION: Although several adverse effects of antidepressants on the gastrointestinal tract have been described (bleeding, constipation, dolichocolon), their influence on gallbladder motility was not investigated.The aim of our study was to investigate the effects of selected antidepressants on gallbladder emptying in patients with major depression. METHODS: The study was set up as an open clinical trial, with the same intervention (ingestion of test meal provoking gallbladder emptying) undertaken in 112 patients with major depression. There were 30 patients not taking antidepressants (the control group), 25 patients taking amitriptyline, 30 patients taking maprotiline, and 27 patients taking fluoxetine. The volume of gallbladder in the study patients was measured by ultrasonography before the test meal, and 15, 30, 45 and 60 min after the meal. RESULTS: 1 h after ingestion of the study meal, the amitriptyline group showed incomplete gallbladder emptying (F=10.829, df=3, p=0.000; mean residual volume 11.0±6.1 mL), while in the control, maprotiline and fluoxetine groups emptying of gallbladder was complete (mean residual volumes 5.0±3.3 mL, 5.6±3.7 mL and 5.7±2.3 mL, respectively). DISCUSSION: In patients with cholecystitis, it would be wise to use antidepressants which do not impair gallbladder emptying, like maprotiline or fluoxetine, and to avoid amitriptyline.

Tempol protects the gallbladder against ischemia/reperfusion.

Impairment in gallbladder emptying, increase in residual volume, and reduced smooth muscle contractility are hallmarks of acute acalculous cholecystitis and seem to be related to ischemia/reperfusion (I/R). This study was designed to determine the effects of tempol, a general antioxidant, on I/R-induced changes in gallbladder contractile capacity, the mechanisms involved in the contractile process, and the level of inflammatory mediators. Experimental gallbladder I/R was induced in male guinea pigs by common bile duct ligation for 2 days, then a deligation of the duct was performed and after 2 days the animals were sacrificed. A group of animals was treated with tempol, administered in the drinking water at 1 mmol/l for 10 days prior the bile duct ligation and until animal sacrifice. Isometric tension recordings showed that KCl and cholecystokinin-induced contractions were impaired by I/R, which correlated with decreased F-actin content and detrimental effects on Ca(2+) influx. In addition, I/R depolarized mitochondrial membrane potential, as indicated by the reduction of the heterogeneity of the rhodamine123 fluorescence signal, and increased the expression of NF-kappaB, COX-2, and iNOS. Tempol treatment improved contractility via normalization of Ca(2+) handling and improvement of F-actin content. Moreover, the antioxidant ameliorated mitochondrial polarity and normalized the expression levels of the inflammatory mediators. These results show that antioxidant treatment protects the gallbladder from I/R, indicating the potential therapeutic benefits of tempol in I/R injury.

[Levosulpiride in the management of functional dyspepsia and delayed gastric emptying]. / Levosulpirida en el manejo de la dispepsia funcional y la gastroparesia.

Levosulpiride is a sulpiride isomer that exerts its prokinetic action through a dual mechanism: 1) as a D(2) dopamine receptor antagonist and 2) as a serotonin 5HT(4) receptor agonist, conferring this drug with a cholinergic effect. At a dosage of 25mg three times daily, levosulpiride accelerates gastric and gallbladder emptying. Clinical trials have shown that this agent is more effective than placebo in reducing the symptoms of dyspepsia, while comparative studies have demonstrated that its effect is similar or superior to that of other dopamine antagonists. The safety profile of levosulpiride is good and the frequency of adverse events is similar to that of other D(2) dopamine antagonists. Therefore, this drug is a useful therapeutic option in the management of patients with functional dyspepsia, as well as in those with delayed gastric emptying.

Glucagon-Like Peptide 2 Inhibits Postprandial Gallbladder Emptying in Man: A Randomized, Double-Blinded, Crossover Study.

INTRODUCTION: A recent study in mice points to the gut-derived hormone glucagon-like peptide 2 (GLP-2) as an important regulator of gallbladder motility inducing gallbladder relaxation and refilling. In this study, we evaluated the effect of exogenous GLP-2 on postprandial gallbladder motility in healthy men. METHODS: In a randomized, double-blinded, placebo-controlled, crossover study, we evaluated the effect of 4-hour intravenous infusions of high-dose GLP-2 (10 pmol × kg × min), low-dose GLP-2 (1 pmol × kg × min), and placebo (saline) on postprandial gallbladder motility. A 300-kcal liquid-mixed meal (added 1.5 g of acetaminophen for indirect measurement of gastric emptying) was served 30 minutes after start of intravenous infusions. Gallbladder volume was assessed by ultrasonography. RESULTS: Fifteen healthy men, age 24.3 (22.4-26.1) years (mean [95% confidence interval]) and body mass index 22.5 (21.7-23.4) kg × m, were included. Basal plasma GLP-2 concentration was 14 (11-17) pmol/L. During low-dose and high-dose GLP-2 infusions, steady-state postprandial plasma GLP-2 concentrations amounted to 201 (188-214) and 2,658 (2,443-2,873) pmol/L, respectively, compared with maximum postprandial plasma GLP-2 concentration of 34 (25-44) pmol/L during placebo. Gallbladder emptying (assessed as baseline-subtracted area under the curve for gallbladder volume) was reduced by low-dose GLP-2 (-0.8 [0.7-1.9] L × min, P < 0.0001) and nearly abolished by high-dose GLP-2 (1.3 [-1.7 to 0.01] L × min, P = 0.029) compared to placebo (-2.0 [-2.8 to -1.1] L × min). Compared to placebo, gastric emptying was reduced by high-dose GLP-2 (P = 0.0060 and 0.019), whereas low-dose GLP-2 did not affect gastric emptying (P = 0.13 and 0.85). DISCUSSION: Exogenous GLP-2 exerts a dose-dependent inhibitory effect on postprandial gallbladder emptying in healthy men.

Utilizing the Cholecystagogue, Ensure Plus, Results in Similar Hepatobiliary Scintigraphy Study Results and Patient Outcomes Status Post Cholecystectomy, in Comparison With Sincalide.

OBJECTIVE: To determine if use of the oral cholecystagogue, Ensure Plus (EP), in hepatobiliary scintigraphy (HBS) leads to a similar distribution of normal and abnormal gallbladder ejection fractions (GBEFs) versus other historical secondary findings of chronic biliary disease in a similar patient population compared with the conventional cholecystokinin analog, sincalide. The HBS findings analyzed included the GBEF, small bowel transit time, gallbladder fill time, and reversal of the normal gallbladder versus small bowel transit. The secondary objectives were to determine whether patient outcomes were significantly different for EP and sincalide HBS study patients following cholecystectomy, namely, the surgical pathology and patient-reported biliary-type pain. METHODS: We reviewed all HBS examinations over a retrospective 34-month period. Data from 446 patients who underwent sincalide or EP HBS with GBEF determination for evaluation of chronic symptoms concerning for biliary etiology met the inclusion criteria. The aforementioned HBS findings and postsurgical patient outcomes were obtained for each patient group. RESULTS: Comparing HBS examinations performed with sincalide or EP, no significant differences were noted in the major HBS findings of similar patient populations. Outcomes for the sincalide and EP groups status post cholecystectomy were assessed to determine their sensitivity, specificity, positive predictive value, and negative predictive value. The outcomes assessed were the histopathology and patient-reported amelioration of biliary-type pain. No significant differences were noted. CONCLUSIONS: The sincalide and EP cholecystagogues did not lead to significantly different HBS findings for similar patient populations or postcholecystectomy outcomes.

Effect of ezetimibe on the prevention and dissolution of cholesterol gallstones.

BACKGROUND & AIMS: Cholesterol cholelithiasis is one of the most prevalent and most costly digestive diseases in developed countries and its incidence has increased markedly in Asian countries owing to the adoption of Western-type dietary habits. Because animal experiments showed that high efficiency of intestinal cholesterol absorption contributes to gallstone formation, we explored whether the potent cholesterol absorption inhibitor ezetimibe could prevent gallstones and promote gallstone dissolution in mice and reduce biliary cholesterol content in human beings. METHODS: Male gallstone-susceptible C57L mice were fed a lithogenic diet and concomitantly administered with ezetimibe at 0, 0.8, 4, or 8 mg/kg/day for 8 or 12 weeks. Gallbladder biles and gallstones were examined by microscopy. Gallbladder emptying in response to cholecystokinin octapeptide was measured gravimetrically. Biliary lipid outputs were analyzed by physical-chemical methods. Cholesterol absorption efficiency was determined by fecal dual-isotope ratio and mass balance methods. Lipid changes in gallbladder biles of gallstone patients vs overweight subjects without gallstones were examined before (day 0) and at 30 days after ezetimibe treatment (20 mg/day). RESULTS: Ezetimibe prevented gallstones by effectively reducing intestinal cholesterol absorption and biliary cholesterol secretion, and protected gallbladder motility function by desaturating bile in mice. Treatment with ezetimibe promoted the dissolution of gallstones by forming an abundance of unsaturated micelles. Furthermore, ezetimibe significantly reduced biliary cholesterol saturation and retarded cholesterol crystallization in biles of patients with gallstones. CONCLUSIONS: Ezetimibe is a novel approach to reduce biliary cholesterol content and a promising strategy for preventing or treating cholesterol gallstones by inhibiting intestinal cholesterol absorption.

New Avenues in the Regulation of Gallbladder Motility-Implications for the Use of Glucagon-Like Peptide-Derived Drugs.

CONTEXT: Several cases of cholelithiasis and cholecystitis have been reported in patients treated with glucagon-like peptide 1 (GLP-1) receptor agonists (GLP-1RAs) and GLP-2 receptor agonists (GLP-2RAs), respectively. Thus, the effects of GLP-1 and GLP-2 on gallbladder motility have been investigated. We have provided an overview of the mechanisms regulating gallbladder motility and highlight novel findings on the effects of bile acids and glucagon-like peptides on gallbladder motility. EVIDENCE ACQUISITION: The articles included in the present review were identified using electronic literature searches. The search results were narrowed to data reporting the effects of bile acids and GLPs on gallbladder motility. EVIDENCE SYNTHESIS: Bile acids negate the effect of postprandial cholecystokinin-mediated gallbladder contraction. Two bile acid receptors seem to be involved in this feedback mechanism, the transmembrane Takeda G protein-coupled receptor 5 (TGR5) and the nuclear farnesoid X receptor. Furthermore, activation of TGR5 in enteroendocrine L cells leads to release of GLP-1 and, possibly, GLP-2. Recent findings have pointed to the existence of a bile acid-TGR5-L cell-GLP-2 axis that serves to terminate meal-induced gallbladder contraction and thereby initiate gallbladder refilling. GLP-2 might play a dominant role in this axis by directly relaxing the gallbladder. Moreover, recent findings have suggested GLP-1RA treatment prolongs the refilling phase of the gallbladder. CONCLUSIONS: GLP-2 receptor activation in rodents acutely increases the volume of the gallbladder, which might explain the risk of gallbladder diseases associated with GLP-2RA treatment observed in humans. GLP-1RA-induced prolongation of human gallbladder refilling may explain the gallbladder events observed in GLP-1RA clinical trials.

Discovery of imidazole carboxamides as potent and selective CCK1R agonists.

High-throughput screening revealed diaryl pyrazole 3 as a selective albeit modest cholecystokinin 1 receptor (CCK1R) agonist. SAR studies led to the discovery and optimization of a novel class of 1,2-diaryl imidazole carboxamides. Compound 44, which was profiled extensively, showed good in vivo mouse gallbladder emptying (mGBE) and lean mouse overnight food intake (ONFI) reduction activities.

Testosterone and dihydrotestosterone inhibit gallbladder motility through multiple signalling pathways.

Testosterone (T) has been shown to cause vasodilation in rabbit coronary arteries through a nongenomic pathway. Part of this T-induced relaxation was shown to be mediated by opening voltage dependent K(+) channels. T infusion also reduces peripheral resistance in human males with heart failure. The effects of T or its active metabolite 5-alpha dihydrotestosterone (DHT) are not well studied. This study investigates the effect of T and DHT on contraction in guinea pig gallbladder strips. T or DHT induced a concentration-dependent relaxation of cholecystokinin octapeptide (CCK)-induced tension. Pretreatment of the strips with PKA inhibitor 14-22 amide myristolated had no significant effect on the relaxation induced by either T or DHT. Pretreatment of strips with 2-APB, an inhibitor of IP(3) induced Ca(2+) release, produced a significant (p<0.001) reduction in the T- or DHT-induced relaxation. Bisindolymaleimide IV and chelerythrine Cl(-) when used in combination had no significant effect on the amount of CCK-induced tension, but significantly (p<0.01) decreased the amount of T- or DHT-induced relaxation. The flavone chrysin, an aromatase inhibitor, and genistein, an isoflavone, each produced a significant (p<0.01) reduction in CCK-induced tension. Chrysin significantly (p<0.05) increased T-induced relaxation; however, genistein had no effect on T-induced relaxation. It is concluded that T and DHT inhibits gallbladder motility rapidly by nongenomic actions of the hormones. Multiple pathways that include inhibition of intracellular Ca(2+) release, inhibition of extracellular Ca(2+) entry, and the actions of PKC may mediate this effect.

Effect of prednisolone administration on gallbladder emptying rate and gallbladder bile composition in dogs.

OBJECTIVE To investigate effects of prednisolone administration on gallbladder emptying rate and gallbladder bile composition in dogs. ANIMALS 6 healthy Beagles. PROCEDURES Prednisolone was administered (2 mg/kg, SC, once daily for 2 weeks) to each dog and tapered over 2 weeks. Gallbladder emptying rate and bile composition were evaluated before and after administration of prednisolone for 2 weeks as well as 1 week after cessation of prednisolone administration. RESULTS Gallbladder emptying rate decreased significantly after prednisolone administration (median, 27%; range, 0% to 38%), compared with rate before administration (median, 59%; range, 29% to 68%), but then increased 1 week after cessation of administration (median, 45%; range, 23% to 48%). Gallbladder bile mucin concentration decreased significantly after prednisolone administration (median, 8.8 mg/dL; range, 6.2 to 11.3 mg/dL), compared with concentration before administration (median, 13.1 mg/dL; range, 10.7 to 21.7 mg/dL), but then increased 1 week after cessation of administration (median, 14.3 mg/dL; range, 9.6 to 26.7 mg/dL). Gallbladder taurochenodeoxycholic acid concentration decreased significantly after prednisolone administration (8.1 mmol/L; range, 6.8 to 15.2 mmol/L), compared with concentration before administration (median, 27.2 mmol/L; range, 22.0 to 31.9 mmol/L), but then increased 1 week after cessation of administration (median, 26.4 mmol/L; range, 15.1 to 31.5 mmol/L). CONCLUSIONS AND CLINICAL RELEVANCE A lower gallbladder emptying rate caused by prednisolone administration may be involved in the pathogenesis of gallbladder disease in dogs. Further studies are required to determine the clinical importance of lower gallbladder bile mucin concentrations caused by glucocorticoid administration in the pathogenesis of gallbladder disease in dogs.

Effects of a Gluten-Containing Meal on Gastric Emptying and Gallbladder Contraction.

The ingestion of gluten has been associated with gastrointestinal symptoms even in the absence of detectable immune responses. Little is known about the pathophysiological effects of gluten on the upper gastrointestinal tract. We aimed to assess whether the ingestion of gluten leads to an impairment of the physiological mechanisms of gastric emptying, gallbladder contraction and relaxation. A total of 17 healthy subjects underwent ultrasound evaluation of gastric emptying dynamics and gallbladder contractions at baseline and every 30 min after a standard gluten-containing and gluten-free meal (250 kcal, 70% carbohydrates). The pattern of gastric emptying was similar after a standard meal with or without gluten, but differed in terms of the peak of the antral filling curve, which was wider (mean area 5.69, median 4.70, range 3.71‒9.27 cm² vs. mean 4.89, median 4.57, 2.27‒10.22 cm², p = 0.023) after the gluten-containing meal. The pattern of gallbladder contractions was different after the gluten-free meal (p < 0.05), with higher gallbladder volumes in the late refilling phases. The results of this study show that gluten ingestion exerts objective effects on gastric and gallbladder motility. Although the underlying pathophysiological mechanism remains unknown, these results could account for some of the gluten-related symptoms reported by patients with celiac disease and non-celiac gluten sensitivity.

Orlistat reduces gallbladder emptying by inhibition of CCK release in response to a test meal.

BACKGROUND AND AIMS: Orlistat is a covalent inhibitor of digestive lipase derived from lipstatin, the natural product of Streptomyces toxytricini. By blocking the active site of intestinal lipase, orlistat inhibits hydrolysis of dietary triglycerides and thus reduces the intestinal lipid absorption. It is uncertain whether intestinal inhibition of lipase by orlistat also interferes with nutrient-induced CCK release from intestinal I-cells. The aim of the present study was therefore to assess whether oral administration of orlistat inhibits CCK release in response to a test meal and thus causes impaired gallbladder emptying. METHODS: 22 healthy volunteers were given a test meal consisting of 200 ml dairy cream and two teaspoons of chocolate powder (552 kcal=2328 kJ; 56.0 g fat; 5.2 g proteins, 6.6 g carbohydrates), with and without oral application of 120 mg orlistat. Gallbladder volume was determined by ultrasound before and 5, 10, 20, 30 and 40 min after meal ingestion. In parallel, a venous blood sample was collected for the measurement of bioactive CCK. CCK activity was assessed using a bioassay with isolated rat pancreatic acini cells. RESULTS: Oral administration of orlistat significantly impairs gallbladder emptying. After ingestion of the test meal the gallbladder contracted by 78.5% in the control group, whereas the test group with orlistat only showed a contraction of 45.7% (p<0.01). Maximal contraction was reached after 35 to 40 min, the maximal gallbladder emptying was delayed up to 10 min by orlistat. Orlistat induced a significant reduction of bioactive CCK levels in response to a test meal (CCK(max) with orlistat=4.1 pmol/l; CCK(max) without orlistat=7.8 pmol/l). CCK levels were reduced by 47% and the onset of maximal CCK secretion was delayed up to 10 min. CONCLUSION: The inhibition of intestinal lipolytic activity by orlistat results in reduced gallbladder emptying through inhibition of meal-mediated CCK release. We therefore hypothesize that impaired gallbladder motility may represent a risk factor in chronic treatment of severe obesity using orlistat.