Nucleation time of gall bladder bile in gall stone patients: influence of bile acid treatment.

The time required for precipitation of cholesterol crystals (nucleation time, NT) was determined and related to the cholesterol saturation in gall bladder bile of gall stone free subjects (n = 11), patients with pigment stones (n = 3), and patients with cholesterol gall stones (n = 30) undergoing cholecystectomy. Seven of the gall stone patients had been treated with chenodeoxycholic acid (CDCA) and nine with ursodeoxycholic acid (UDCA), 15 mg/kg/day for three weeks before operation. NT was longer in gall stone free subjects (mean, 20 days), patients with pigment stones (14 days) and patients treated with CDCA (24 days) and UDCA (17 days) compared with untreated patients with cholesterol gall stones (1.5 days). In spite of low cholesterol saturation and prolonged NT, and in contrast to those treated with CDCA, four of the nine patients treated with UDCA had cholesterol crystals in their bile. These observations give further support to the concept that the mechanism for inducing gall stone dissolution may be different for CDCA and UDCA.     

Combination therapy with oral ursodeoxycholic and chenodeoxycholic acids: pretreatment computed tomography of the gall bladder improves gall stone dissolution efficacy.

In a five year study, 55 patients with radiolucent gall stones were treated with the combination of 7.5 mg chenodeoxycholic acid (CDCA) and 5.0 mg ursodeoxycholic acid (UDCA)/kg/day--that is, half the monotherapeutic doses. Side effects were few but four patients could not tolerate the prescribed bile acids because of diarrhoea or nausea. Analysis of fasting duodenal bile confirmed that CDCA+UDCA converted supersaturated into unsaturated bile but the saturation indices did not predict the dissolution response. By actuarial analysis, the confirmed (by ultrasound x2) complete gall stone dissolution rates in all 55 patients were mean (SEM) 29 (7)% at 12 and 44 (8)% at 24 months. The advent of routine computed tomography before treatment enabled comparison of dissolution efficacy in those screened by computed tomography (n = 24), whose maximum gall stone attenuation was less than 100 Hounsfield units, with that in those not screened (n = 29). Although stone size and number were comparable, patients screened by computed tomography had significantly better dissolution rates (p less than 0.025) than those not screened in this way. At 12 months, partial or complete gall stone dissolution rates were 93 (7)% in the screened and 55 (11)% in the non-screened patients. At 18 months, complete dissolution rates were 64 (12%) and 20 (9)% respectively. Computed tomography before treatment is cost effective in selecting those patients likely to achieve gall stone dissolution on treatment with UDCA+CDCA.     

Hepatic biliary lipid secretion and gall bladder biliary lipid mass in gall stone patients: effect of ursodeoxycholic acid.

We have carried out overnight measurements of hepatic secretion rate and duodenal output of biliary lipids using a duodenal perfusion technique. We correlated these measurements with the fasting state mass of biliary lipids within the gall bladder on the following morning using a combined nasoduodenal intubation and isotope scanning technique. We studied six gall stone subjects before and during treatment with ursodeoxycholic acid 675 mg/day. Lipid mass within the gall bladder correlated with the corresponding overnight hepatic secretion rate for all three biliary lipids. During ursodeoxycholic acid treatment, there was an increase in gall bladder bile acid mass without significant change in cholesterol or phospholipid mass. We conclude that the mass of individual biliary lipids within the fasting gall bladder is influenced by overnight hepatic biliary lipid secretion rate; and that the effect of ursodeoxycholic acid (675 mg/day) on cholesterol saturation index of fasting gall bladder bile is mediated via an increase in bile acid mass rather than through a decrease in cholesterol mass within the gall bladder.     

Faecal bile acid loss and bile acid pool size during short-term treatment with ursodeoxycholic and chenodeoxycholic acid in patients with radiolucent gallstones.

Twelve non-obese patients with radiolucent gallstones were fed on a standard diet. After 10 days (period A), six patients received 15 mg/kg/day of ursodeoxycholic acid (UDCA) (group I) and the other six (group II) the same dose of chenodeoxycholic acid (CDCA) for 15 days (period B). An intravenous injection of 20 micro Ci of 14C-UDCA and of 14C-CDCA was given on the 11th day of period B to the patients of group I and II respectively. Stools were collected at the end of period A and B and one bile sample was collected on the 12th day of period B. The faecal bile acid loss was higher during chenotherapy (36.12 mumol/kg/day) than during ursotherapy (23.94 mumol/kg/day), as was the proportion of lithocholic acid (73% vs 43%) in the faeces. Decay constant rate of faecal radioactivity was 0.365 day-1 in group I and 0.642 in group II. The results indicate that faecal bile acid excretion and turnover rate are greater during CDCA than UDCA, while UDCA increases the bile acid pool size to an even greater extent than does CDCA (150.2 vs 94.9 mumol/kg). This is probably because the former is more slowly degraded to poorly reabsorbable compounds. In fact, the bile saturation index was 0.66 in group I and 1.05 in group II, even though biliary CDCA in the latter had risen to 69.6%.     

Distribution of cholesterol between vesicles and micelles in human gallbladder bile: influence of treatment with chenodeoxycholic acid and ursodeoxycholic acid

The present study aimed at determining the relative distribution of cholesterol between the vesicular and micellar phases in gallbladder bile of gallstone patients (n = 23) and gallstone-free subjects (n = 7). Nine of the gallstone patients were treated with chenodeoxycholic acid and seven were treated with ursodeoxycholic acid, 15 mg/kg/day, for 3 wk before cholecystectomy. The vesicular and micellar fractions in bile were separated by sucrose density gradient ultracentrifugation, and a clear separation between the two phases was obtained. The vesicles were further identified by quasielastic light scattering spectroscopy and appeared to be of a uniform size with a mean hydrodynamic radius of 760 A. The proportion of cholesterol in the vesicular fraction was significantly higher in the untreated gallstone group (40% +/- 4%) compared with the gallstone-free (28% +/- 3%), ursodeoxycholic acid (28% +/- 3%) and chenodeoxycholic acid (18% +/- 4%) groups. Despite a low cholesterol saturation of bile in the latter three groups (88% +/- 12%, 51% +/- 9% and 65% +/- 5%, respectively), a considerable part of the biliary cholesterol was carried in the vesicular fraction. The cholesterol/phospholipid ratio in the vesicular fraction averaged between 0.49 and 0.58 in the gallstone, gallstone-free and chenodeoxycholic acid groups, whereas the ursodeoxycholic acid group had a significantly lower ratio of 0.24. The nucleation time of bile from the gallstone group was short (2 +/- 1 days) compared with the gallstone-free, chenodeoxycholic acid and ursodeoxycholic acid groups (23 +/- 3, 24 +/- 6 and 14 +/- 3 days, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Optimum bile acid treatment for rapid gall stone dissolution.

To determine the optimum bile acid regimen for rapid gall stone dissolution, 48 gall stone patients were divided into four groups of 12 according to stone diameter and were randomly allocated to receive one of four treatment regimens: bedtime or mealtime chenodeoxycholic acid (CDCA, 12 mg/kg/day) and bedtime or mealtime ursodeoxycholic acid (UDCA, 12 mg/kg/day). An additional 10 patients treated with a combination of CDCA plus UDCA (each 6 mg/kg/day) at bedtime were matched with the 10 patients on bedtime CDCA and the 10 on bedtime UDCA. The gall stone dissolution rates at six and 12 months were determined by standardised oral cholecystography and expressed as the percentage reduction in the gall stone volume after treatment. The gall stone dissolution rate at six months was higher for UDCA than CDCA treatment (median 78% v 48%, p less than 0.01), and for bedtime than mealtime administration (69% v 39%, p less than 0.02). Both differences were greater for stones less than 8 mm diameter. The dissolution rate was faster for combination therapy than for CDCA alone at both six (82% v 36%, p less than 0.05) and 12 months (100% v 54%, p less than 0.05), but was not different from UDCA alone. We conclude that bile acid treatment should be confined to patients with small gall stones and that bedtime administration of combined UDCA and CDCA is likely to provide the most effective and safe combination.     

Increased activity of ionised calcium in gall bladder bile in gall stone disease.

The actual activity of ionised calcium (Ca2+) in gall bladder bile determined with an ion-selective electrode was significantly higher in patients with gall stone disease (n = 15) than in patients without gall stones (n = 10) (0.43 mmol/kg v 0.31 mmol/kg; p < 0.05). No change in the Ca2+ activity in any of the gall bladder bile samples was observed during equilibration with CO2. During titration with HCl/NaOH, however, the Ca2+ activity fell with increasing pH in a biphasic manner, with the breaking point occurring at a significantly lower median pH in patients with gall stones than in patients without (pH 7.1 v 8.2; p < 0.0001). The combination of a higher activity of calcium in bile and precipitation of bile salts taking place at a lower pH in patients with gall stone disease than in patients without gall stones suggests a major role for calcium and pH in the pathogenesis of gall stones. Strict anaerobic sampling is not necessary for the measurements of Ca2+ in gall bladder bile, because the Ca2+ was not significantly affected by the changes in pCO2. The metabolic studies suggest, however, that simultaneous measurements of the activity of Ca2+ and pH is important in order to interpret data for the calcium activity in gall bladder bile.     

Effect of ursodeoxycholic acid and chenodeoxycholic acid on cholesterol and bile acid metabolism

Orally administered UDCA dramatically reduces the secretion of cholesterol into the bile. During UDCA therapy cholesterol balance is maintained by a reduction in both the relative and absolute absorption of cholesterol and, perhaps, by a combined moderate enhancement of bile acid synthesis and a suppression of cholesterol production. The percentage of UDCA in the bile is limited by the inability of UDCA to suppress bile acid synthesis from cholesterol and by the conversion of UDCA to CDCA by the intestinal bacteria.     

Transformation of chenodeoxycholic acid to ursodeoxycholic acid in patients with Crohn's disease

In vivo 7 beta-epimerization of chenodeoxycholic acid to ursodeoxycholic acid and the role of 7-ketolithocholic acid as an intermediate in this biotransformation were studied in 11 patients with Crohn's disease and in 5 healthy volunteers. The incorporation of deuterium into biliary ursodeoxycholic acid and 7-ketolithocholic acid was determined by computed gas chromatography-mass fragmentography after ingestion of a dideuterated chenodeoxycholic acid, chenodeoxycholic-11,12-d2 acid. The incorporation of deuterium into ursodeoxycholic acid increased to a peak level at 48 h in the patients with Crohn's disease, but was delayed in healthy volunteers. In 8 patients and 2 healthy controls there were small amounts of 7-ketolithocholic acid in bile. The incorporation of deuterium into 7-ketolithocholic acid was confirmed in only 2 patients and the peak level was noted at 48 h. These observations suggest that 7-ketolithocholic acid is an intermediate of this biotransformation in patients with Crohn's disease.     

Quantitative ultrastructural studies of gall bladder epithelium in gall stone free subjects and patients with gall stones.

The present study aimed at a further evaluation of the role of glycoproteins in the formation of cholesterol gall stones in man. An electron microscopic morphometric study of the gall bladder epithelium was performed in six gall stone free subjects and 12 gall stone patients. Six of the gall stone patients were treated with ursodeoxycholic acid three weeks before cholecystectomy. The number and the volume density of the mucin containing secretory granules, were not significantly increased in gall stone patients compared with gall stone free subjects. Treatment with ursodeoxycholic acid did not affect the number or volume density of the secretory granules. Thus, these results do not give evidence for that the degree of cholesterol saturation influences mucin content in the gall bladder wall of man. A major new finding was that gall stone patients had a markedly reduced total lysosome area and volume density of lysosomes compared with gall stone free subjects, a finding which may be related to a decreased intracellular degradation of protein and/or mucin.     

Composition of gall bladder stones associated with octreotide: response to oral ursodeoxycholic acid.

Octreotide, an effective treatment for acromegaly, induces gall bladder stones in 13-60% of patients. Because knowledge of stone composition is essential for studies of their pathogenesis, treatment, and prevention, this was investigated by direct and indirect methods in 14 octreotide treated acromegalic patients with gall stones. Chemical analysis of gall stones retrieved at cholecystectomy from two patients, showed that they contained 71% and 87% cholesterol by weight. In the remaining 12 patients, localised computed tomography of the gall bladder showed that eight had stones with maximum attenuation scores of < 100 Hounsfield units (values of < 100 HU predict cholesterol rich, dissolvable stones). Gall bladder bile was obtained by ultrasound guided, fine needle puncture from six patients. All six patients had supersaturated bile (mean (SEM) cholesterol saturation index of 1.19 (0.08) (range 1.01-1.53)) and all had abnormally rapid cholesterol microcrystal nucleation times (< 4 days (range 1-4)), whilst in four, the bile contained cholesterol microcrystals immediately after sampling. Of the 12 patients considered for oral ursodeoxycholic acid (UDCA) treatment, two had a blocked cystic duct and were not started on UDCA while one was lost to follow up. After one year of treatment, five of the remaining nine patients showed either partial (n = 3) or complete (n = 2) gall stone dissolution, suggesting that their stones were cholesterol rich. This corresponds, by actuarial (life table) analysis, to a combined gall stone dissolution rate of 58.3 (15.9%). In conclusion, octreotide induced gall stones are generally small, multiple, and cholesterol rich although, in common with spontaneous gall stone disease, at presentation some patients will have a blocked cystic duct and some gall stones containing calcium.     

Gall stone disease without gall stones--bile acid and bile lipid metabolism after complete gall stone dissolution.

Although bile acid and bile lipid metabolism have been studied in established cholelithiasis, little is known about them in patients destined to develop gall stones, but in whom the stones have not yet appeared (prestone gall stone disease). After confirmed complete gall stone dissolution and withdrawal of treatment, gall stones recur frequently. Before the stones reappear, these patients have 'poststone gall stone disease'. In 13 such patients we confirmed complete gall stone dissolution with two normal cholecystograms and in 11 of the 13 by normal ultrasonography, measured bile acid and bile lipid composition in fasting duodenal bile, bile acid synthesis from marker corrected three day faecal bile acid excretion, bile acid pool size using an abbreviated isotope dilution technique, 'steady-state' bile lipid secretion using a duodenal amino acid perfusion system and then calculated the enterohepatic cycling frequency of the bile acid pool and the relationship between pool size and body weight. The results confirm that after withdrawal of treatment the biliary cholesterol saturation index reverts to levels (1.6 +/- SEM 0.4) comparable with those before dissolution therapy first began (1.6 +/- 0.2; NS). The mean bile acid pool size in the 13 patients of 4.4 +/- 0.5 mmol was comparable with that in untreated gall stone patients. Pool size was significantly smaller in the nine non-obese patients (3.5 +/- 0.3), than in the four obese (6.0 +/- 0.8; p less than 0.05). It also correlated significantly with body weight (r = 0.72) and with %IBW (r = 0.79). The coefficients of variation for biliary bile acid, phospholipid and cholesterol secretion were high, but the mean hourly secretion rates were of the same order as those seen in untreated gall stone patients studied with the amino acid duodenal perfusion stimulus. These results provide a baseline for assessing the response to postdissolution treatment and may indicate metabolic events leading to gall stone formation.     

Modulation of bile secretion by hepatic low-density lipoprotein uptake and by chenodeoxycholic acid and ursodeoxycholic acid treatment in the hamster

The effects of both apolipoprotein B,E receptor-dependent and receptor-independent uptake of low-density lipoprotein (LDL) in the liver on bile secretion were studied in bile fistula hamsters. Three groups of animals were studied after 4 wk of feeding either a control, chenodeoxycholic acid-, or ursodeoxycholic acid-containing diet. The hepatic receptor-dependent and receptor-independent uptake of LDL was related to both bile flow and biliary lipid secretion. The correlation with bile flow and biliary lipid secretion was positive for the receptor-dependent, but negative for the receptor-independent uptake of LDL. Although the receptor-mediated LDL uptake appeared to exert a strong influence on bile acid-independent bile flow, the receptor-independent uptake showed a significant relation with biliary bile acid excretion. Differences between the two mechanisms of LDL uptake were also evident in the biliary bile acid-cholesterol coupling, which was significantly stronger during receptor-independent than during receptor-dependent uptake of LDL. The effects of LDL uptake on bile secretion were modulated by the experimentally induced changes in both the content and composition of bile acids in the enterohepatic circulation.     

Reduced cholesterol metastability of hepatic bile and its further decline in gall bladder bile in patients with cholesterol gall stones.

The reduced metastability of biliary cholesterol in the gall bladder bile of patients with cholesterol gall stones has been well shown. The purpose of this study was to examine the hypothesis that such a difference in metastability already exists in hepatic bile. Paired hepatic and gall bladder bile samples were collected from 10 patients with cholesterol gall stones and six patients without gall stones. Cholesterol nucleation time, biliary lipid concentration, vesicular cholesterol distribution, and biliary protein concentration were measured and compared. The nucleation time in the hepatic bile of patients with cholesterol gall stones was significantly shorter than the gall stone free patients (8.2 (7.2) v 15.7 (5.8) days, p < 0.05), and was associated with a greater concentration of biliary lipid despite the lack of a difference in the cholesterol saturation index (CSI) and total protein concentration. During the storage of bile in the gall bladder, the nucleation time became quicker in the patients with cholesterol gall stone (2.9 (1.7) days) while it was similar in the gall stone free patients (17.3 (5.7) days) compared with that of the corresponding hepatic bile. These differences were associated with a higher CSI (1.44 (0.33) v 1.13 (0.14), p < 0.05) and a greater vesicular cholesterol distribution (19.7 (11.9) v 4.4 (1.4)%, p < 0.01) in the patients with cholesterol gall stones than the gall stone free patients. The concentrations of total lipid and protein in gall bladder bile were not significantly different between the two groups. In conclusion, patients with cholesterol gall stones produce less metastable hepatic bile by the evidence of shorter nucleation time. During the storage of the bile in the gall bladder, the metastability is reduced further only in the cholesterol gall stone patients but not in the gall stone free patients.     

Bile acids in bile during long-term chenodeoxycholic acid treatment.

Relative concentrations of conjugated and sulfated bile acids in duodenal bile were measured in 5 patients before and during treatment with 0.50-0.75 g of chenodeoxycholic acid per day for 3-4 months. Lithocholic acid constituted 0.8-3.3% (mean 1.8%) of total conjugated and sulfated bile acids before and 0-5.4% (mean 2.6%) during treatment. Lithocholic acid was the predominant bile acid in the sulfate fraction in three patients and chenodeoxycholic acid in two. Sulfated bile acids constituted less than 1% of total bile acids and did not increase during treatment. Ursodeoxycholic acid, the other major metabolite of chenodeoxycholic acid, was found in higher amounts during therapy. The unsaturated bile acid 3beta-hydroxy-delta5-cholenic acid, which was found exclusively as its sulfate ester, showed a slight fall. The average G/T conjugation ratio rose from 2.2 to 4.5.     

Deoxycholic acid in gall bladder bile does not account for the shortened nucleation time in patients with cholesterol gall stones.

The relations between the concentration of deoxycholic acid (DCA), the cholesterol saturation index, and the nucleation time in gall bladder bile were measured to determine the role of DCA in bile in the pathogenesis of cholesterol gall stone disease. Bile was obtained from patients with cholesterol gall stones (n = 30), subjects without gall stones (n = 35), and patients with pigment gall stones (n = 9). Three of 30 cholesterol gall stone patients and 10 of 35 gall stone free subjects were treated with antibiotics by mouth to decrease the concentration of bile DCA and determine the effect of DCA on biliary lithogenecity. Both the percentage and concentration of DCA in bile were similar in patients with and without cholesterol gall stones despite significant differences in their cholesterol saturation indices and nucleation times. Neither the percentage nor the concentration of DCA in bile correlated with either the cholesterol saturation index or the nucleation time. Analysis of subgroups with matching cholesterol saturation indices showed no correlation between the proportion of DCA in the bile and the cholesterol nucleation time. The proportion of DCA in bile was decreased by antibiotic treatment, but this had no effect on the cholesterol saturation index or nucleation time. These results suggest that DCA in bile is not responsible for biliary cholesterol saturation or cholesterol nucleation time.     

Differing effects of ursodeoxycholic or chenodeoxycholic acid on biliary cholesterol saturation and bile acid metabolism in man

A dose-response study comparing ursodeoxycholic and chenodeoxycholic acid was carried out in six men with asymptomatic radiolucent gallstones present in well-visualizing gallbladders. The study tested the effects of a low (averaging 6 mg/kg/day) or medium dose (averaging 11 mg/kg/day) of each bile acid on the cholesterol saturation of bile as well as on bile acid metabolism, as inferred from biliary and fecal bile acid composition. Ursodeoxycholic acid, at low or medium doses, induced bile desaturation in most patients, whereas chenodeoxycholic acid did not. Despite the greater desaturation efficacy of ursodeoxycholic acid, biliary bile acids became less enriched with the administered bile acid during ursodeoxycholic acid treatment than during chenodeoxycholic acid treatment. Both bile acids were nearly completely 7-dehydroxylated to lithocholic acid by colonic bacteria, but biliary lithocholic increased only slightly (and similarly) with each bile acid. Fecal bile acid composition suggested that administered ursodeoxycholic acid suppressed endogenous bile acid synthesis much less than chenodeoxycholic acid. The results indicate that ursodeoxycholic acid and chenodeoxycholic acid have similar but not identical effects on bile acid metabolism, but that for a given dose, ursodeoxycholic acid is a more potent desaturating agent than chenodeoxycholic acid. The results suggest that cholesterol gallstone dissolution with ursodeoxycholic acid should occur with a dose of 8–10 mg/kg in most nonobese patients.Supported in part by NIH grants AM 15887, 16770, and 21506.     

Ursocholic acid: bile acid and bile lipid dose response and clinical studies in patients with gall stones.

The biliary bile acid and bile lipid responses to six weeks treatment with approximately 5, 10, and 15 mg/kg/day of ursocholic acid (UCA) were studied in 11 gall stone patients. Maximum enrichment of bile with UCA (24 (SE) 4.9%) occurred with 15 mg UCA/kg/day. The maximum reduction in biliary cholesterol saturation was seen with the 10 mg/kg/day dose when the moles % cholesterol fell from 14 (2.4)% before treatment to 5.6 (0.83)% (p less than 0.02) and the saturation index fell from 1.4 (0.23) to 0.77 (0.13) (p less than 0.05). Clinical studies of the safety and efficacy of UCA in dissolving gall stones were carried out in 13 patients treated for up to two years with a dose of approximately 10 mg/kg/day. Diarrhoea caused withdrawal of treatment in three patients. There were no significant changes in liver function or haematology tests but fasting serum cholesterol tended to rise during treatment. Of nine patients treated for greater than 6 months, only one showed complete gall stone dissolution. As UCA may cause diarrhoea and hypercholesterolaemia, has only a modest effect on biliary cholesterol saturation and low gall stone dissolution efficacy, it is unlikely to replace existing forms of gall stone dissolution therapy.