Gallstone formation during weight-reduction dieting

We investigated the development of gallstones over an 8-week period from the onset of dieting in 51 obese men and women and 26 nondieting control subjects. Gallbladder examinations were performed by abdominal real-time ultrasonography for the detection of gallstones. Initial sonography was performed prior to dieting and only those subjects in whom initial sonograms showed no gallstones or sludge were included in the study. Repeated sonography was performed at 4-week intervals for 8 weeks while they remained on a 2100-kJ/d diet. Initial weight of subjects prior to dieting averaged 105.9 +/- 3.8 kg (162% of ideal body weight) and decreased to 89.4 +/- 3.2 kg (137.3% of ideal body weight) after 8 weeks of dieting. Sonography performed after 4 weeks of dieting revealed new-onset gallbladder sludge in 1 subject and gallstones in 4 subjects. After 8 weeks of dieting sludge was detected in 3 subjects and gallstones in 13 (25.5%). In contrast, none of the nondieting subjects developed any detectable gallbladder abnormalities. During the dieting period, 1 of 51 subjects developed symptoms of biliary colic, necessitating cholecystectomy. On cessation of dieting with reinstitution of normal feeding, 2 additional subjects with stones developed symptoms severe enough to require cholecystectomy. In all 3 cases, cholesterol gallstones were recovered at the time of surgery. Eleven of the 13 patients with gallstones were followed up for 6 months after discontinuation of the diet. Besides the 3 undergoing cholecystectomy, 4 subjects had gallstones on follow-up ultrasound examination, while sonographically detectable gallstones had disappeared in 4 subjects. We conclude that this form of weight-reduction dieting predisposes to the development of gallstones and that gallstone formation is a risk of this type of prolonged calorie restriction. Dissolution or evacuation of gallstones may occur with resumption of a normal diet.     

Changes in gallbladder motility and gallstone formation following laparoscopic gastric banding for morbid obestity.

Morbid obesity is associated with cholesterol gallstone formation, a risk compounded by rapid weight loss. Laparoscopic gastric banding allows for a measured rate of weight loss, but the subsequent risk for developing gallstones is unknown. METHOD: Twenty-six normal-weight volunteers (body mass index [BMI] less than 30) were compared with 14 morbidly obese patients (BMI greater than 40). Gallbladder volumes were measured ultrasonographically, after fasting and following stimulation with intravenous cholecystokinin-octapeptide (CCK-8) RESULTS: Preoperatively, fasting gallbladder volume and residual volume after CCK stimulation were both two times greater in the obese group (P<0.02 versus controls). Per cent gallbladder emptying was not different. Gallbladder refilling was four times higher in the obese patients (P<0.01). By six weeks postoperatively, the obese patients lost 1.4+/-0.1% body weight per week. Gallbladder emptying decreased 18.4% (80.3+/-3.9% to 65.5+/-6.9%; P<0.05); residual volume rose one-third (not significant), and refilling fell 60.5% (0.43+/-0.09 to 0.26+/-0.04 mL/min; P=0.07). Three patients with weight losses of greater than 1.7% per week developed gallstones; gallbladder emptying fell outside the 95 percentile. By six months, weight loss slowed to 0.5+/-0.1% per week; gallbladder motility improved modestly. No further stones developed. CONCLUSION: Rapid weight loss following laparoscopic gastric banding impairs gallbladder emptying and when pronounced, gallstones form by six weeks postoperatively. The accompanying reduction in gallbladder emptying, increased gallbladder residual volume and decreased refilling promote gallbladder stasis and hence stone formation.     

Sluggish small bowel motility is involved in determining increased biliary deoxycholic acid in cholesterol gallstone patients

OBJECTIVE: Our aim was to establish whether small intestine transit time is defective in subjects with cholesterol gallstones. METHODS: We enrolled 10 patients (eight women, two men; mean age, 48.7 yr; mean body mass index [BMI], 22.4 Kg/m2) with recently diagnosed cholelithiasis, with no liver pathology, who were not taking any drugs, and 11 comparable healthy volunteers (eight women, three men; mean age, 46.2 yr; mean BMI, 22.7 Kg/m2), who served as controls. All subjects underwent orocecal (by starch breath test technique and serum assays of salazopyrin), oroileal (by serum assays of tauroursodeoxycholic acid), and duodenoileal (by serum assays of taurocholic acid) transit times; cholesterol saturation index; and bile acid composition and gallbladder motility studies (by ultrasound). For serum assays, blood samples were collected over a period of 7 h. Gallbladder motility and orocecal transit time were evaluated simultaneously. RESULTS: All four means of assessing transit time gave longer times in cholesterol gallstone patients than in controls: orocecal transit time (salazopyrin) = 366 +/- 13 vs 258 +/- 16 min, p < 0.0005; orocecal transit time (starch breath test) = 415 +/- 139 vs 290 +/- 15 min, p < 0.01; duodenoileal transit time: 272 +/- 23 vs 205 +/- 23 min, p < 0.03; and oroileal transit time: 308 +/- 18 vs 230 +/- 19 min, p < 0.009. Cholesterol gallstone patients showed an increase in percent molar biliary deoxycholic acid (30% +/- 4.5% vs 16% +/- 1.3%, p < 0.02) and a decrease in percent molar cholic acid 32% +/- 2.2% vs 40% +/- 1.3%, p < 0.03) and chenodeoxycholic acid (34% +/- 3% vs 41% +/- 1.8%, p < 0.03), compared with controls; patients also had greater percent molar biliary cholesterol. A linear relationship (r2 = 0.6324, p = 0.0012) between biliary deoxycholic acid and small bowel transit time was found. Residual gallbladder volumes were larger in cholesterol gallstone patients (11.38 +/- 1.27 vs 7.55 +/- 0.39 ml, p < 0.04), whereas basal gallbladder volumes, although higher, did not reach statistical significance (24.25 +/- 2.41 vs 19.98 +/- 1.63 ml; p = ns). CONCLUSIONS: This study confirms that patients with cholesterol gallstones have delayed small bowel transit, defective gallbladder motor function, and increased biliary deoxycholic acid. Delayed small bowel transit may contribute to supersaturation of bile with cholesterol by increasing deoxycholic acid production.     

Changes in gallbladder bile composition following gallstone formation and weight reduction.

Changes in gallbladder bile composition that occurred in patients who developed gallstones during weight reduction were evaluated. Bile was sampled directly from the gallbladder in 11 morbidly obese patients with no gallstones at the time of gastric bypass surgery and after gallstones had formed at cholecystectomy. Bile salt concentration ([BS]) increased significantly from a mean of 82.7-157.7 mmol/L (P less than 0.05). The concentration of cholesterol in gallbladder bile increased slightly and cholesterol saturation declined slightly with weight reduction and gallstone formation. Gallbladder mucin concentration increased 18-fold from a mean of 62 to 1110 micrograms/mL (P less than 0.001). Both free [Ca2+] and total calcium [Ca] increased 40% from mean values of 1.12 and 5.05 mmol/L at gastric bypass to 1.86 and 8.60 mmol/L after gallstone formation (P less than 0.05). The increase in [Ca2+] observed after gallstone formation was much greater than anticipated from changes in [BS] alone. This excess [Ca2+] in gallbladder bile increased curvilinearly with increasing mucin concentration. These results show that both gallbladder mucin and [Ca2+] increase with gallstone formation in humans and that mucin may modulate [Ca2+] in gallbladder bile.     

Cholesterol metabolism in human gallbladder mucosa: relationship to cholesterol gallstone disease and effects of chenodeoxycholic acid and ursodeoxycholic acid treatment.

The objective of this study was to investigate cholesterol metabolism in human gallbladder mucosa, especially in relation to hepatic cholesterol metabolism, gallstone disease and treatment with bile acids. Gallbladder mucosa and liver tissue samples were collected in 44 patients undergoing cholecystectomy; 30 had cholesterol gallstones and the rest were stone free. Ten of the gallstone patients were treated with chenodeoxycholic acid and eight received ursodeoxycholic acid, with a daily dose of 15 mg/kg body wt, for 3 wk before surgery. The 3-hydroxy-3-methylglutaryl coenzyme A reductase activity, governing cholesterol synthesis, was considerably lower in the gallbladder mucosa than in liver tissue (28 +/- 6 and 120 +/- 40 pmol/min/mg protein). The acyl coenzyme A:acyltransferase activity in the gallbladder mucosa catalyzing the esterification of cholesterol was, on the other hand, several times higher than corresponding activity in the liver (92 +/- 23 and 11 +/- 2 pmol/min/mg protein). In the presence of exogenous cholesterol, the acyl coenzyme A:acyltransferase activity increased about twofold in the gallbladder mucosa. The acyl coenzyme A:acyltransferase activity of the gallbladder mucosa from untreated gallstone patients was not stimulated further by the addition of exogenous cholesterol. Otherwise, there were no significant differences in acyl coenzyme A:acyltransferase and 3-hydroxy-3-methylglutaryl coenzyme A reductase activities in the gallbladder mucosa of gallstone patients compared with gallstone-free controls. Treatment with chenodeoxycholic and ursodeoxycholic acids did not affect the 3-hydroxy-3-methylglutaryl coenzyme A reductase activity of the gallbladder mucosa but reduced the acyl coenzyme A:acyltransferase activity by 60% to 65%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of NSAIDs on gallbladder bile composition

Secretion of gallbladder mucin is an important step in gallstone pathogenesis. Previous studies have demonstrated that aspirin and other nonsteroidal antiinflammatory drugs (NSAIDs) can both inhibit gallbladder mucin secretion and prevent gallstone formation in animal models of cholesterol gallstone disease. The present study was performed to determine if chronic NSAID use was associated with a reduction in the mucin content or affected the lipid components of human gallbladder bile. Four groups of patients were identified retrospectively from a cohort of 230 morbidly obese patients who underwent gastric bypass surgery. The index group consisted of 18 patients who were found to have gallstones at gastric bypass surgery and had a history of chronic NSAID use. Three other patient groups were identified from the cohort by matching this index population for sex, race, and age according to the following criteria: (1) patients with gallstones who had not utilized NSAIDs, (2) patients without gallstones but with chronic NSAID use, and (3) patients without gallstones and without a history of NSAID use. Gallbladder bile was obtained from all patients by direct aspiration from the gallbladder at the time of surgery. Patients with gallstones had a significantly (P<0.02) greater concentration of gallbladder mucin in their gallbladder bile compared to patients without gallstones (0.897±0.226 vs 0.173±0.039 mg/ml). Among gallstone patients, gallbladder mucin was reduced in those patients with a history of chronic NSAID use (1.18±0.43 vs 0.74±0.19 mg/ml). Chronic NSAID use was also associated with a reduction in the cholesterol/phospholipid ratio of gallbladder bile in patients with and without gallstones. These data suggest that chronic NSAID use may later the mucin and lipid content of gallbladder bile in a manner that could reduce the risk for gallstone formation.Supported by NIH-FIRST award DK43264 (M.L.S.) and NIH grant DK47628 (E.W.M.) from the National Institutes of Digestive and Kidney Diseases.     

Small gallstones, preserved gallbladder motility, and fast crystallization are associated with pancreatitis

Acute pancreatitis is a severe complication of gallstones with considerable mortality. We sought to explore the potential risk factors for biliary pancreatitis. We compared postprandial gallbladder motility (via ultrasonography) and, after subsequent cholecystectomy, numbers, sizes, and types of gallstones; gallbladder bile composition; and cholesterol crystallization in 21 gallstone patients with previous pancreatitis and 30 patients with uncomplicated symptomatic gallstones. Gallbladder motility was stronger in pancreatitis patients than in patients with uncomplicated symptomatic gallstones (minimum postprandial gallbladder volumes: 5.8 +/- 1.0 vs. 8.1 +/- 0.7 mL; P = .005). Pancreatitis patients had more often sludge (41% vs. 13%; P = .03) and smaller and more gallstones than patients with symptomatic gallstones (smallest stone diameters: 2 +/- 1 vs. 8 +/- 2 mm; P = .001). Also, crystallization occurred much faster in the bile of pancreatitis patients (1.0 +/- 0.0 vs. 2.5 +/- 0.4 days; P < .001), possibly because of higher mucin concentrations (3.3 +/- 1.9 vs. 0.8 +/- 0.2 mg/mL; P = .04). No significant differences were found in types of gallstones, relative biliary lipid contents, cholesterol saturation indexes, bile salt species composition, phospholipid classes, total protein or immunoglobulin (G, M, and A), haptoglobin, and alpha-1 acid glycoprotein concentrations. In conclusion, patients with small gallbladder stones and/or preserved gallbladder motility are at increased risk of pancreatitis. The potential benefit of prophylactic cholecystectomy in this patient category has yet to be explored.     

Prevention or surgical treatment of gallstones in patients undergoing gastric bypass surgery for obesity

Opinion statement It is well known that obesity is a risk for gallstone formation and biliary sludge. Additionally, it has been clearly shown that rapid weight loss following bariatric surgery is a risk factor for cholesterol cholelithiasis. Multiple serious complications from gallstones such as cholecystitis, cholangitis, gallstone pancreatitis, and cholecystenteric fistulae may occur. Thus, it is necessary to employ medical or surgical methods to prevent or treat gallstones in this group. Therapy should be individualized. Although there is a high incidence of gallstones in this group, only a minority of individuals will develop symptomatic disease. When used in patients who are compliant, ursodeoxycholic acid therapy can be effective to prevent gallstone formation during rapid weight loss. The cost effectiveness of routine ursodeoxycholic acid therapy compared with the potential costs of complicated gallstone disease needs to be further investigated. Combined cholecystectomy with Roux-en-Y gastric bypass surgery is a safe and appropriate therapeutic option in those with preoperatively known gallstones, biliary sludge, and prior episodes of cholecystitis. However, routine cholecystectomy at the time of gastric bypass surgery is not warranted for all patients because of the increased time of operation and postoperative hospitalization, as well as all the potential complications after cholecystectomy. The approach of routine cholecystectomy in this setting subjects many patients to an unnecessary procedure because the majority will not develop symptoms or complications of gallstones. Furthermore, cholecystectomy is technically easier to perform after weight loss occurs.     

Gallbladder filling and emptying during cholesterol gallstone formation in the prairie dog. A cholescintigraphic study

We studied gallbladder bile flow before, during, and after cholesterol gallstone formation in the prairie dog using infusion cholescintigraphy with 99mTc-diethyl iminodiacetic acid. In 18 fasting animals partitioning of bile between gallbladder and intestine was determined every 15 min for 140 min, and gallbladder response to cholecystokinin (5 U/kg X h) was calculated from the gallbladder ejection fraction. Ten prairie dogs were then placed on a 0.4% cholesterol diet and 8 on a regular diet, and the studies were repeated 1, 2, and 6 wk later. The proportion of hepatic bile that entered the gallbladder relative to the intestine varied from one 15-min period to the next, and averaged 28.2% +/- 5.1% at 140 min. Partial spontaneous gallbladder emptying (ejection fraction 11.5% +/- 5.6%) was intermittently observed. Neither the number nor the ejection fraction of spontaneous gallbladder contractions changed during gallstone formation. By contrast, the percent of gallbladder emptying in response to cholecystokinin decreased from 72.1% +/- 5% to 25.9% +/- 9.3% (p less than 0.025) in the first week and was 14.3% +/- 5.5% at 6 wk (p less than 0.01 from prediet values, not significant from first week). Gallbladder filling decreased from 28.2% +/- 5.1% to 6.7% +/- 3% (p less than 0.01), but this change was only observed after 6 wk, when gallstones had formed. This study shows that bile flow into the gallbladder during fasting is not constant; the gallbladder contracts intermittently; gallbladder emptying in response to exogenous cholecystokinin is altered very early during gallstone formation; and gallbladder filling remains unaffected until later stages, when gallstones have formed.     

Nucleation time and lithogenic index in obese patients and in patients with cholecystolithiasis

The gallbladder bile of obese patients without gallstones is supersaturated with cholesterol. The cholesterol saturation index (CSI, LI) of 27 obese patients was 1.32 +/- 0.2. The CSI of 24 normal weight gallstone patients was determined with 1.16 +/- 0.37 and is therefore not significantly different from CSI of obese stone free individuals. The supersaturated bile from obese patients does not accelerated the nucleation of cholesterol crystals. The nucleation time of obese persons was statistically significant longer (16.0 +/- 3.0 days) than in gallstones patients (6.0 +/- 0.78 days) (p less than 0.001). In 50% of the patients with gallstones cholesterol monohydratcrystals were present in the native gallbladder bilde, whereas such crystals are found in only 3.7% of the obese group. Liquid crystals occurred more frequently and in larger number in the bile of the obese patients. The stone forming potency of gallbladder bile can be estimated better by the determination of nucleation time and cholesterol crystals occurrence than by the calculation of the saturation index (CSI).     

Changes in gallbladder bile composition and crystal detection time in morbidly obese subjects after bariatric surgery

The aim of the present study was to elucidate the mechanisms of development of cholesterol crystals and gallstones during weight reduction in obese subjects. Twenty-five morbidly obese, gallstone-free subjects underwent vertical-banded gastroplasty. Gallbladder bile was collected at the time of the operation via needle aspiration and 1.1-7.3 months after the operation via ultrasound-guided transhepatic puncture of the gallbladder. The mean weight loss was 17 kg. Two patients developed gallstones and 10 patients displayed cholesterol crystals in their bile. In patients with a follow-up time of less than 2 months (n = 13), cholesterol saturation increased from 90% to 114% but tended to decrease in the patients with a follow-up time of more than 2 months. The extraction of the concanavalin-A-binding fraction from gallbladder bile obtained after weight reduction in 7 patients prolonged crystallization detection time from 6 to 10 days. The hexosamine concentration, a marker for mucin, was increased by about 100% in bile obtained in 6 of 7 patients after weight reduction. In conclusion, the results indicate that crystallization-promoting compounds (mucin) are of great importance in the development of cholesterol crystals and gallstones in obese subjects during weight reduction, probably because of defective gallbladder emptying.     

Composition and immunofluorescence studies of biliary "sludge" in patients with cholesterol or mixed gallstones

BACKGROUND/AIMS: Gallbladder bile from patients with cholesterol or mixed gallstones frequently contains biliary "sludge", a suspension of cholesterol monohydrate crystals and pigment granules embedded in mucin and proteins. The composition of biliary "sludge" and the preferential localization of mucin and proteins could be an indicator for its potential role in gallstone formation. METHODS: Ultracentrifugation (100000 g/l h) was used to precipitate "sludge" from bile, and the concentration difference of its main components between native bile and ultracentrifuged bile samples was calculated. After purification of the sediment, immunolocalization was performed for the detection of mucin, IgA, albumin, aminopeptidase, and anionic polypeptide fraction using polyclonal and monoclonal antibodies. RESULTS: The amount of sludge in gallbladder bile was 4.26 mg/ml-0.78 (mean+/-SEM) in patients with cholesterol and 2.51 mg/ml+/-0.39 in patients with mixed stones and cholesterol was the main component (48.9+/-4.6% and 44.4+/-7.1%). The sediment appeared as a mixture of vesicular aggregates and pigment particles which were linked by a gel matrix of mucin containing cholesterol crystals. While anionic polypeptide fraction and aminopeptidase were associated to pigments, IgA was uniformly spread in the crystalline parts of "core-like" structures, and albumin, when it was present, appeared as randomly located small spots. CONCLUSIONS: Our study demonstrates that the cholesterol content and the distribution pattern of mucin and different proteins is similar in the sediments of biliary "sludge" to that previously shown in cholesterol and mixed gallstones. This suggests that biliary "sludge" represents an early stage of gallstone formation in these patients.     

Risk factors for the development of gallstone recurrence following medical dissolution. The British-Italian Gallstone Study Group

OBJECTIVE: To assess risk factors for gallstone recurrence following non-surgical treatment. DESIGN: A prospective follow-up of a multicentre cohort of post-dissolution gallstone patients. SETTING: Six gastroenterology units in the UK and Italy. PARTICIPANTS: One hundred and sixty-three patients with confirmed gallstone dissolution following non-surgical therapy (bile acids or lithotripsy plus bile acids), followed up by ultrasound scan and clinical assessment at 6-monthly intervals for up to 6 years (median, 25 months; range, 6-70 months). OUTCOME MEASURES: Subject-related variables (sex, age, height, weight, body mass index), gallstone-related variables (number, diameter, presence of symptoms, months to complete stone clearance), treatment modalities (bile acid therapy, extracorporeal shock wave lithotripsy) and follow-up related variables (weight change, use of non-steroidal anti-inflammatory agents, statins, pregnancies and/or use of oestrogens) were assessed by univariate and multivariate analysis as putative risk factors for gallstone recurrence. RESULTS: Forty-five gallstone recurrences were observed during the follow-up period. Multiple primary gallstones and length of time to achieve gallstone dissolution were the only variables associated with a significant increase in the recurrence rate. Appearance of biliary sludge during follow-up was also significantly related to development of gallstone recurrence. Use of statins or non-steroidal anti-inflammatory agents did not confer protection against recurrence. CONCLUSIONS: Patients with primary single stones are the best candidates for non-surgical treatment of gallstones, because of a low risk of gallstone recurrence. The positive association of recurrence with biliary sludge formation and time to dissolution of primary stones may provide indirect confirmation for the role of impaired gallbladder motility in the pathogenesis of this condition.     

Gallstones in obesity and weight loss

The prevalence of cholesterol gallstones is increased in obese persons. The risk is especially high in those with the highest body mass index (relative risk 5-6). Weight loss further increases the risk of gallstones: the prevalence of new gallstones reaches 10-12% after 8-16 weeks of low-calorie diet and more than 30% within 12-18 months after gastric by-pass surgery. About one-third of the stones are symptomatic. The increased prevalence of stones is mostly due to supersaturation of bile with cholesterol, because of an increased synthesis by the liver and secretion into bile. Saturation is further increased during weight loss. It returns toward normal after weight stabilization at a lower level, allowing spontaneous stone dissolution in some cases. Identified risk factors for gallstones during weight loss are a relative loss of weight greater than 24% of initial body weight, a rate of weight loss greater than 1.5 kg per week, a very low calorie diet with no fat, a long overnight fast period and a high serum triglyceride level. Ursodeoxycholic acid decreases cholesterol saturation of bile and gallstone incidence during weight loss. Other preventive measures include a control of weight loss rate, a reduction of the length of overnight fast, and maintenance of a small amount of fat in the diet.     

Increase in serum total cholesterol and low-density lipoprotein cholesterol by high-dose chenodeoxycholic acid in patients with radiolucent gallstones significantly reversed during preventive low dose after gallstone dissolution

This study examines the effects of high-dose chenodeoxycholic acid (CDCA) on serum lipids and lipoproteins in 25 patients who underwent a 12-month therapy with CDCA for the dissolution of cholesterol gallstones. All patients received a daily dose of CDCA of 15 mg/kg body weight. Complete dissolution of gallstones was achieved in 16 cases. After 6 months of therapy the mean total cholesterol levels and low-density lipoprotein cholesterol (C-LDL) significantly increased (p less than 0.001). The decrease of mean triglyceride levels was significant too (p less than 0.01), although it was greater among patients with effective gallstone dissolution than in patients with persistent gallstones. The effects of high-dose CDCA after 12 months of therapy were similar to those observed at 6 months. 12 patients of the gallstone dissolution group were treated with a continuous low dose of CDCA (250 mg/day) for preventing gallstone recurrence. 6 months after dissolution, the mean total cholesterol levels and C-LDL significantly decreased (p less than 0.01 and less than 0.05, respectively). High-dose administration of CDCA produced an increase in total cholesterol and C-LDL, but did not alter high-density lipoprotein cholesterol levels. These effects were significantly reversed when a preventive low dose of CDCA was given after gallstone dissolution.     

Gallbladder Motility and Lithogenesis in Obese Patients During Diet-Induced Weight Loss

Obesity and weight loss are important risk factors for gallstone development. The mechanisms involved are unknown. We prospectively studied changes in gallbladder (GB) emptying and bile composition during weight loss. We studied 12 alithiasic obese subjects who entered a six-month diet program (800–1200 kcal/day, 26 g fat/day). As controls we evaluated 12 healthy nulliparous nonobese young women. GB volumes were studied by ultrasonography (fasting volume, GBFV; residual volume after a liquid meal, GBRV) at entry and after 4 and 20 weeks of dieting. Bile acid pool size, biliary lipid composition, presence of cholesterol crystals, and nucleation time were also studied. Of 12 obese subjects studied (mean BMI 35.1 kg/m²), 10 remained in the program for six months, but only six completed the entire study protocol, obtaining a significant weight loss (BMI: 31.2 kg/m², P < 0.001). GBFV was greater in obese subjects than in nonobese controls (27.5 ± 10.7 vs 11.7 ± 6 ml; P < 0.05). GBRV and GB emptying curves were similar in both groups and did not change during weight loss. The obese subject who developed gallstones (1/10) was the only one who had cholesterol crystals in bile and a sluggish initial GB emptying. In conclusion: (1) obese subjects had a greater GBFV than controls; however, the GB emptying was adequate. (2) During weight loss we did not observe significant changes in GB kinetics or the bile parameters studied. (3) We observed a relatively low frequency of gallstone formation, which can be explained by a high fat content of the diet (26 g/day) and by the adequate GB emptying of our group of patients. (4) An abnormal GB contractility and cholesterol crystals in bile could be considered premonitory to gallstone formation.     

Age-associated gallstone formation in male and female CCK-1(A) receptor-deficient mice

Background Gallbladder dysmotility accelerates cholelithiasis. In turn, gallbladder dysmotility can occur secondary to inflammation and excess cholesterol accumulation in gallbladder smooth muscle. Methods The present study was designed to determine how much gallbladder dysmotility contributes to gallstone formation as a primary cause and whether a sex difference exists in gallstone formation by comparing cholecystokinin-1 receptor gene-deficient [CCK-1R(−/−)] male and female mice. Results No sludge or gallstone formation was observed in mice at 6 months of age. The frequency of sludge and gallstone formation in mice at 12 and 24 months of age was slightly higher in female CCK-1R(−/−) mice than in males, but the difference was not significant. Conclusions Gallbladder dysmotility may have accelerated sludge and gallstone formation, but its contribution was limited. A 12-month period was required to produce gallstones, and after the mice reached 12 months of age, further ageing did not increase the frequency of gallstones. The effect of sex did not reach a significant level.     

Influence of gallstones and ursodeoxycholic acid therapy on gallbladder emptying

Altered gallbladder motility could predispose to, or result from, gallstone formation and could also explain the alleged relief of biliary colic seen during bile acid therapy. Therefore, in 14 controls, 25 patients with radiolucent gallstones, and 14 patients with radiopaque gallstones, we used two techniques to measure gallbladder contraction--radionuclide imaging and real-time ultrasound--in response to one of two stimuli--a Lundh meal or intravenous cholecystokinin-octapeptide. Using the radionuclide technique, postprandial gallbladder emptying (t1/2) was prolonged (p less than 0.01) both in patients with radiopaque (26.7 +/- 3.1 min, mean +/- SEM) and radiolucent (21.7 +/- 3.1) gallstones when compared with controls (10.2 +/- 1.5). In patients with radiolucent stones, the t1/2 of gallbladder emptying became further prolonged (p less than 0.05) after 1 mo of therapy with 8-10 mg/kg body wt X day of ursodeoxycholic acid, to 32.1 +/- 4.4 min. A similar pattern of results was seen after cholecystokinin-octapeptide and also with real-time ultrasound. Thus, after both stimuli and using two independent techniques, gallbladder contraction was reduced in patients with gallstones. The slower and less complete gallbladder emptying with ursotherapy might explain the reduction in biliary colic noted during treatment.     

Effect of prolonged feeding with chenodeoxycholic acid on bile in patients with and without gallstones.

Nineteen patients who received chenodeoxycholic acid 750 mg/day for six months had duodenal bile aspirated before and after treatment. In five patients with hypertriglyceridaemia but no gallstones cholesterol saturation was reversed in every case, the mean cholesterol saturation index (SI +/- standard deviation) changing from 1-38 +/- 0-31 to 0-68 +/- 0-06 (P less than 0-005). In 14 patients with gallstones there was also an improvement in bile cholesterol content, but this was not sufficient to produce mean unsaturation, saturation index changing from 1-55 +/- 0-52 to 1-13 +/- 0-43 (P less than 0-05). Only seven of 14 patients with gallstone achieved cholesterol unsaturation. In four patients with hypertriglyceridaemia and gallstones, mean unsaturation was produced and the saturation index changed from 1-70 +/- 0-45 to 0-86 +/- 0-47 (P less than 0-05). When all nine patients with hypertriglyceridaemia were grouped, the mean saturation index fell from 1-52 +/- 0-40 to 0-76 +/- 0-30 after therapy (P less than 0-001). In contrast the 10 patients without hypertriglyceridaemia showed no significant fall in saturation index which was 1-50 +/- 0-54 before and 1-24 +/- 0-40 after therapy. The ability of chenodeoxycholic acid feeding to improve bile saturation with cholesterol correlated with the presence of hypertriglyceridaemia whether or not gallstones were present. It did not correlate with gallstone dissolution or body weight.     

Lack of response to chenodeoxycholic acid in obese and non-obese patients. Role of cholesterol synthesis and possible response to ursodeoxycholic acid.

This paper describes seven patients with radiolucent gallstones in functioning gallbladders who did not respond to chenodeoxycholic acid (CDCA). Despite large doses (greater than or equal to 19 mg CDCA/kg/day), CDCA-rich bile (CDCA conjugates 70-97% of total biliary bile acids) and greater than or equal to one year's treatment, their fasting duodenal bile remained supersaturated with cholesterol and their gallstones did not dissolve. Five patients came to cholecystectomy, gallstone analysis and liver biopsy for measurement of hepatic cholesterogenesis (HMGCoAR activity). In three who stopped CDCA before surgery, the mean HMGCoAR (pmol/mg microsomal protein/min) of 50.2 was higher than in our untreated gallstone controls (32.2 +/- SEM 2.0; P less than 0.05). Two patients who took CDCA until surgery had a mean HMGCoAR of 33.5--more than twice that in CDCA-treated gallstone controls. These findings suggest that non-response to CDCA may be related to high or unsuppressed hepatic cholesterogenesis. In one patient who did not respond to CDCA, treatment with 19 mg ursodeoxycholic acid/kg/day did desaturate his bile.