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

Effect of ursodeoxycholic acid on serum lipids of patients with primary biliary cirrhosis

OBJECTIVE

To study the effects of ursodeoxycholic acid (UDCA) on lipid levels in patients with primary biliary cirrhosis (PBC).

DESIGN

A randomized, placebo-controlled prospective trial of UDCA was conducted in 177 well-characterized patients with PBC.

MATERIAL AND METHODS

The two treatment groups (placebo and UDCA) were matched at entry with respect to age, sex, histologic stage of PBC, biochemical values, and serum lipid levels. Serum cholesterol, high-density lipoprotein cholesterol, and triglyceride levels were measured at entry, 1 year, and 2 years.

RESULTS

The decrease in total cholesterol level at 1 and 2 years in the UDCA-treated group was significant in comparison with that in the placebo group. Serum high-density lipoprotein cholesterol and triglyceride levels, however, were unchanged. No severe side effects from UDCA were noted. The changes in serum cholesterol levels at 2 years were directly and strongly correlated with changes in serum bilirubin concentrations (r = 0.70; P < 0.001) and inversely correlated with initial serum cholesterol levels (r = -0.86; P < 0.00001).

CONCLUSION

The cholesterol-lowering effect of UDCA could be related to amelioration of the underlying liver disease or to a direct effect of the drug on the metabolism of cholesterol in patients with hypercholesterolemia.

Effect of chenodeoxycholate and ursodeoxycholate on nucleation time in human gallbladder bile

The effects of treatment with chenodeoxycholic acid (CDCA) or ursodeoxycholic acid (UDCA) on nucleation time, biliary lipid concentration, and vesicular lipid composition were studied. Gallbladder bile was collected at the time of surgery from 33 cholesterol gallstone patients who were divided into three groups: 16 untreated, 9 pretreated with CDCA (400 mg/day), and 8 pretreated with UDCA (600 mg/day) for 1-3 weeks before surgery. Control bile samples were also collected from nine patients without cholelithiasis. Nucleation time was prolonged significantly in both CDCA- and UDCA-treated groups [12.6 +/- 8.5 (SD) and 21.0 +/- 0 days, respectively] compared with the untreated gallstone group (3.3 +/- 3.2 days). Both treatments significantly decreased the proportion and concentration of both cholesterol and phospholipids present in the vesicular phase. Treatment with UDCA decreased the cholesterol saturation index more than did CDCA at the dose used in this study. In the CDCA-treated group, patients without much change in cholesterol saturation index (greater than 1.0) showed a prolongation of the nucleation time with a significant decrease in vesicular cholesterol concentration, indicating a shift of cholesterol from vesicles to micelles. UDCA-treated patients and CDCA-treated patients with decreased cholesterol saturation index (less than 1.0) showed a greater effect. The authors conclude that UDCA prolongs the nucleation time mainly by decreasing the cholesterol saturation index, whereas CDCA does so by the dual effect of lowering the cholesterol saturation index and shifting cholesterol from vesicles to micelles.

Effect of chronic administration of ursodeoxycholic acid on the ileal absorption of endogenous bile acids in man

The effect of long-term administration of ursodeoxycholic acid on the ileal absorption of endogenous bile acids was determined using the tauro 23 (75Se) selena-25 homotaurocholic acid test in a controlled double-blind study involving healthy subjects (n = 15). Subjects received placebo or 13 to 15 mg/kg/day ursodeoxycholic acid for 5 wk. In the placebo group (n = 7) there was no change in the composition of serum bile acids or in the mean percentage of retention of tauro 23(75Se) selena-25 homotaurocholic acid (36.1% +/- 6.0% vs. 38.7% +/- 6.7%). In contrast, in the ursodeoxycholic acid group, serum ursodeoxycholic acid conjugates increased and the percentage of retention of tauro 23 (75Se) selena-25 homotaurocholic acid fell from 45.8% +/- 6.8% to 20.5% +/- 5.7% (p less than 0.01). We conclude that ursodeoxycholic acid administration reduces ileal absorption of endogenous bile acids. These findings provide a rational explanation for the changes in the composition of the bile acid pool during ursodeoxycholic acid therapy and could have important therapeutic implications.

Faecal steroid loss in healthy subjects during short-term treatment with ursodeoxycholic acid

Faecal steroid loss in healthy subjects during short-term treatment with ursodeoxycholic acid has been investigated. The data shows conclusively that lithocholic acid, a known co-mutagen and co-carcinogen is the major bacterial metabolite of ursodeoxycholic acid in the human intestine. Although ursodeoxycholic acid is now the drug of choice for dissolution of cholesterol gallstones, elevation of intestinal lithocholic acid may have long-term repercussions since it has been demonstrated that a high faecal lithocholic acid: deoxycholic acid ratio shows a positive correlation with the incidence of colorectal cancer.

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.

Gallstone dissolution with ursodeoxycholic acid in patients with chronic active hepatitis and two years follow-up. A pilot study

Chemical dissolution of cholesterol gallstones using ursodeoxycholic acid (UDCA) in six patients with histologically confirmed HBsAg-negative chronic active hepatitis was started after a minimum of one year of therapy with steroids, azathioprine, or chloroquine and a treatment-free period of 8-15 months. The treatment with UDCA lasted 3-20 months with a daily dose of 8-11 mg/kg. Four patients served as controls. A decrease in transaminases (P less than 0.05) occurred in all patients during the UDCA therapy. After completion of the treatment, the figures rose again, but did not return to the initial value. The stones dissolved in five patients. A second liver biopsy was carried out in two patients after UDCA therapy, and this showed no detectable deterioration. Four patients refused biopsy because the laboratory parameters had improved under UDCA. A stone recurred in one patient six months after the end of therapy; the others have remained free of stones for up to 24 months.

Cholesterol absorption and sterol balance in normal subjects receiving dietary fiber or ursodeoxycholic acid

Twelve normal subjects were placed on a constant diet and evaluated during three treatment periods, each lasting four weeks. Patients received regular diet alone during period A, regular diet plus 60 g/day wheat bran during period B, and regular diet plus 15 mg/kg/day ursodeoxycholic acid during period C. Cholesterol absorption, plasma lipid concentration, daily fecal excretion of neutral and acidic sterols, and sterol balance were determined following each treatment. No changes in serum lipid levels are observed in the three study periods. Bran administration increases fecal neutral sterol excretion and decreases cholesterol absorption (from 50.1 to 42.0%) with respect to period C. Ursodeoxycholic acid administration has no effect on fecal neutral sterol excretion, whereas bile acid excretion is markedly increased. Sterol balance (evaluated as neutral and acidic fecal sterols excreted per day minus dietary cholesterol plus ursodeoxycholic acid given per day) is lower during ursodeoxycholic acid feeding (360 +/- 145 mg/day) than during bran feeding (593 +/- 174 mg/day). In conclusion, ursodeoxycholic acid decreases sterol balance values; bran-rich diet increases sterol balance and reduces cholesterol absorption.

The role of bile acids in colonic carcinogenesis

Several line of evidence suggest that bile acids may be implicated in the pathogenesis of colonic cancer. A high consumption of fat and animal protein and a low dietary intake of fiber have been shown to be related to the incidence of colonic cancer. From these epidemiologic observations the hypothesis was proposed that the correlation between diet and colon cancer might be explained by the involvement of bile acids. Populations at a high risk of developing cancer were shown to have an increased excretion both of total and bacterially modified bile acids in their feces. Animal studies demonstrated a cocarcinogenic effect of bile acids and experimental diets containing large amounts of fat did not only induce an increased bile acid excretion but also an enhanced tumor formation in the colon. Furthermore, microbial in vitro tests showed a comutagenic activity of secondary bile acids. However, case control studies comparing the fecal bile acid excretion pattern in colonic cancer patients and control subjects failed to show such a clear relationship, which might be explained by rather similar dietary habits within one population and individual differences in sensitivity to environmental factors contributing to the tumor development. Cholecystectomy, leading to an increased exposure of bile acids to the intestinal microflora, has been suggested as a predisposing factor for the development of colonic cancer, but the results of experimental and epidemiologic studies so far are rather inconsistent.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of acute administration of bile acids on fatty acid composition of biliary phosphatidylcholine in man

Little is known on variations in fatty acid composition of biliary phosphatidylcholine (PC) during acute administration of particular bile acids (BAs) in man. Bile was collected hourly for 5 h in 6 T-tube patients (prereplacement period). Thereafter particular BAs were infused into the duodenum at a rate of 1 g/h for 5 h and bile collected hourly (replacement period). Each patient received two BAs at an interval of 3 days, following a cross-over design. Three patients received deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA) and a second 3 patients cholic acid (CA) and chenodeoxycholic acid (CDCA). Bile acid pool contained mainly the two primary BAs in the prereplacement period and more than 80% administered BAs in the replacement period. Hydrophobic and detergent BAs (DCA and CDCA) increased the secretion rates and the percentage of biliary PC species with arachidonic acid and stearic acid; in contrast less detergent BAs (UDCA and CA) did not significantly alter fatty acid composition of biliary PC. Thus, very hydrophobic and detergent BAs would seem to promote the preferential secretion into the bile of lecithin species present in the liver cell plasma membranes, rich in arachidonic and stearic acid.

Analysis of metabolic profiles of steroids in faeces of healthy subjects undergoing chenodeoxycholic acid treatment by liquid-gel chromatography and gas-liquid chromatography-mass spectrometry

The multicomponent analysis of faecal steroids is described. Steroids were removed from faeces by solvent stripping in a Soxhlet apparatus and the resulting extracts were fractionated by diethylaminohydroxypropyl Sephadex column chromatography into neutral sterols, free bile acids, glycine conjugated bile acids, taurine conjugated bile acids and sulphated steroids. In this study the method has been applied for faecal steroid analyses of healthy subjects undergoing chenodeoxycholic acid therapy. Chenodeoxycholic acid administration causes a considerable increase in the concentration of faecal lithocholic acid which is a known comutagenic bile acid. Furthermore it has been shown that conjugated bile acids can account for between 10 and 20% of the faecal bile acid pool. The method described is convenient and may be useful for epidemiological studies which require a large number of faecal samples to be analysed.

Relationships between squalene and cholesterol in bile: effect of ursodeoxycholic acid administration in patients with radiolucent gallstones

Squalene is an obligate intermediate of cholesterol synthesis and plasma squalene to cholesterol ratio correlates significantly with cholesterol synthesis rate in the liver. Sixteen nonobese patients with radiolucent gallstones were randomly allocated into two treatment groups receiving 15 mg/kg/day ursodeoxycholic acid (group A) or 15 mg/kg/day lactose (group B) administered three times daily for 30 days. In group A, biliary squalene to cholesterol ratio was significantly lowered (from 1.19 to 0.86, P less than 0.02), as was cholesterol saturation (from 1.39 to 0.95, P less than 0.001); levels of plasma very-low-density lipoprotein cholesterol (VLDL-C) (from 30 to 26 mg/dL) and plasma VLDL-triglyceride (VLDL-TG) (from 81 to 68 mg/dL) decreased significantly only in the group taking ursodeoxycholic acid. No variations of squalene concentrations and squalene to cholesterol ratio were observed in the plasma of both groups. Biliary cholesterol saturation during ursodeoxycholic acid administration correlated directly with squalene to cholesterol ratio in bile; reduction of these two parameters is accompanied by decreased VLDL-C levels.

Synthesis, intestinal absorption and metabolism of sarcosine conjugated ursodeoxycholic acid

Sarcosine conjugated ursodeoxycholic acid (SUDC) was synthesized and its intestinal absorption and metabolism were studied in rat and hamster. Intestinal absorption study using bile fistula rat shows that more than 90% of SUDC administered intraduodenally was excreted in the bile within 24 hr. No change of the administered bile acid was seen during the absorption from the intestine, the passage of the liver, and the excretion into the bile. When [24-14C]SUDC and [11,12-3H2]-ursodeoxycholic acid were administered orally to a hamster, more than 95% of both the administered 14C and 3H were recovered from the feces within 6 days. Most (77%) of the fecal 14C-labeled compound was SUDC, whereas 95% of the fecal 3H-labeled compound was unconjugated lithocholic acid. These results indicate that SUDC, unlike taurine or glycine conjugated bile acid, resists bacterial deconjugation and 7-dehydroxylation.

Ursodeoxycholic acid: a review of its pharmacological properties and therapeutic efficacy

Ursodeoxycholic acid is the 7 beta-hydroxy epimer of chenodeoxycholic acid and is normally present in only trace amounts in the bile. Oral administration of pharmacological doses markedly decreases biliary cholesterol saturation. Complete or partial dissolution of radiolucent gallstones located in a functioning gallbladder occurred in about 40 to 55% of patients treated with ursodeoxycholic acid in controlled studies of 6 months duration. Patients showing partial gallstone dissolution at that time are likely to continue improving possibly to complete gallstone dissolution with continued therapy. The success rate with ursodeoxycholic acid may be increased top about 80% if more stringent patient selection criteria are applied to include only those with non-calcified floating cholesterol stones of less than 10 to 15 mm diameter. Those with calcified stones or stones greater than 15 mm diameter or unlikely to respond to ursodeoxycholic acid therapy. The optimal dose in published studies was about 8 to 10 mg/kg/day, which is about half to two-thirds the dose of chenodeoxycholic acid (15 mg/kg/day) achieving approximately equivalent results. Ursodeoxycholic acid appears to be remarkably well tolerated, with diarrhoea occurring in only a very small proportion of patients. While surgery is clearly the preferred treatment in many patients with symptomatic gallstones, in a carefully selected subgroup of such patients gallstone dissolution therapy with ursodeoxycholic acid offers an important and worthwhile alternative.

Medical treatment of biliary duct stones: effect of ursodeoxycholic acid administration

Twenty-eight patients with radiolucent biliary duct stones without cholangitis and jaundice were randomly allocated into two treatment groups receiving ursodeoxycholic acid 12 mg/kg (group A) or placebo (group B) in three daily doses for 24 months. In group A stones disappeared completely in seven patients and partially in one; placebo administration had no effect on stone size and three patients of group B (only one of group A) went to surgery for complications. Ursodeoxycholic acid treatment did not adversely affect liver function tests, and alkaline phosphatase decreased. Abdominal and biliary colics also became less frequent in the first six months of therapy in group A, but not in the placebo group. The bile was supersaturated with cholesterol in both groups, but decreased significantly only in patients receiving ursodeoxycholic acid even though the lithogenic index remained high. Cholesterol saturation of bile does not seem to be the only factor determining the dissolution of biliary duct stones which sometimes contain cholesterol as the main component.

A combination of chenodeoxycholic acid and ursodeoxycholic acid is more effective than either alone in reducing biliary cholesterol saturation

The effects on biliary lipids of 10 mg per kg per day of chenodeoxycholic acid (CDCA), 10 mg per kg per day of ursodeoxycholic acid (UDCA), and their equimolar combination (5 mg per kg per day of each), all administered for 45 to 60 days, were investigated in 18 patients with gallstones in a double-blind study with a balanced latin square design. The molar percentage of cholesterol in bile (initial value 9.7 +/- 2.2) was significantly lower after UDCA (5.4 +/- 1.3) and the combination (5.2 +/- 1.2) than after CDCA (7.2 +/- 1.7). Nevertheless, when the ability to solubilize cholesterol was calculated, taking into account the percentage of biliary UDCA, then the differences in cholesterol saturation induced by UDCA alone and the combination also became considerable (saturation index: 0.94 +/- 0.12 as compared to 0.81 +/- 0.12). The total bile acid pool increased significantly after treatment with CDCA and the combination, but not after UDCA. Lithocholic acid was increased significantly only by treatment with CDCA. Diarrhea was observed in five patients with hypertransaminasemia and in four patients after CDCA, whereas both UDCA and the combination were well-tolerated. We conclude that the administration of a combination of equimolar doses of CDCA and UDCA can be recommended for medical treatment of gallstones since it has greater effects on bile cholesterol saturation than either alone, is better tolerated than CDCA, and is less expensive than UDCA.

Differing effects of ursodeoxycholic or chenodeoxycholic acid on biliary cholesterol saturation and bile acid metabolism in man. A dose-response study

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.

Fecal bile acid analysis in healthy Japanese subjects using a lipophilic anion exchanger, capillary column gas chromatography and mass spectrometry

Detailed fecal bile acid profiles of healthy Japanese subjects were studied using a lipophilic anion exchanger, capillary gas chromatography and mass spectrometry. Total dairy excretion of bile acid into feces corrected for by fecal markers were between 127.99 to 366.33 mumole per day. Unconjugated bile acids constituted a major part, between 80 and 96%, of fecal bile acids. Glycine conjugated, taurine conjugated and sulfated bile acids were between 1 to 6, 0 to 3 and 1 to 10%, respectively. Esterified bile acids at C-24 position existed between 1 to 5%. Primary bile acids ranged from 0 to 55%. There were a number of epimers of hydroxy- and keto-bile acids, and lithocholic and deoxycholic acid were major secondary bile acids among them. A cholenoic acid was detected in the unconjugated fraction of one subject. It seems necessary to analyze the details not only on the type of bile acids but also on the mode of conjugation in biological samples. Thus, the methodology described in this study has made it easier to investigate on the role of bile acid in the physiology or pathophysiology of the gastrointestinal tract.

Chenodeoxycholic acid: a review of its pharmacological properties and therapeutic use

Chenodeoxycholic acid (chenic acid; CDCA) is 1 of the 3 major biliary bile acids in man. When administered in pharmacological doses it causes a decrease in cholesterol saturation of bile, which in turn may lead to gradual dissolution of cholesterol gallstones. The stone dissolution rate during CDCA therapy has varied considerably from about one-third of patients overall to 80 to 90% in a highly selected group of patients. Radiolucent gallstones in a functioning gallbladder are absolute requirements. CDCA is well tolerated; diarrhoea (sometimes requiring dosage reduction) is the only frequent side effect. Although hepatotoxicity has occurred in certain animal species, and slight hypertransaminasaemia has occurred in some patients, definite liver damage has not been observed in man. CDCA is considered contraindicated in pregnancy, and in those patients with the complications from gallstones which require immediate surgery. Care should be taken in patients with liver disease. The only other proven agent for dissolving gallstones is the 7 beta-epimer of CDCA, ursodeoxycholic acid (UDCA). Preliminary results show that UDCA is as effective as CDCA, but at one-half to two-thirds the dose, without causing diarrhoea. Further studies need to be done with both CDCA and UDCA to improve criteria for selection of patients most likely to respond, and to establish optimum schedules for dosage and duration of treatment.