Long-Term Ursodeoxycholic Acid Therapy Does Not Alter Lithocholic Acid Levels in Patients with Cystic Fibrosis with Associated Liver Disease.

OBJECTIVE: To evaluate the fasting and postprandial serum bile acid composition in patients with cystic fibrosis-associated liver disease (CFLD) after chronic administration of ursodeoxycholic acid (UDCA) (20 mg/kg/day). The aim was to specifically focus on the extent of biotransformation of UDCA to its hepatotoxic metabolite, lithocholic acid, because of recent concerns regarding the safety of long-term, high-dose UDCA treatment for CFLD. STUDY DESIGN: Twenty patients with CFLD (median age 16 years, range: 2.4-35.0) prescribed UDCA therapy for at least 2 years were studied. Total and individual serum bile acids were measured by stable-isotope dilution mass spectrometry, in fasting and 2-hour postprandial samples taken during chronic UDCA (20 mg/kg/day) administration. RESULTS: During chronic UDCA administration (median duration 8 years, IQR: 6-16), UDCA became the predominant serum bile acid in all patients (median, IQR: 3.17, 1.25-5.56 µmol/L) and chenodeoxycholic acid concentrations were greater than cholic acid (1.86, 1.00-4.70 µmol/L vs 0.40, 0.24-2.71 µmol/L). The secondary bile acids, deoxycholate and lithocholate, were present in very low concentrations in fasted serum (<0.05 µmol/L). After UDCA administration, 2-hour postprandial concentrations of both UDCA and chenodeoxycholic acid significantly increased (P < .01), but no significant changes in serum lithocholic acid concentrations were observed. CONCLUSION: These data do not support recent suggestions that enhanced biotransformation of UDCA to the hepatotoxic secondary bile acid lithocholic occurs when patients with CFLD are treated with relatively high doses of UDCA.

Impaired oxidoreduction by 11ß-hydroxysteroid dehydrogenase 1 results in the accumulation of 7-oxolithocholic acid.

11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) mediates glucocorticoid activation and is currently considered as therapeutic target to treat metabolic diseases; however, biomarkers to assess its activity in vivo are still lacking. Recent in vitro experiments suggested that human 11ß-HSD1 metabolizes the secondary bile acid 7-oxolithocholic acid (7-oxoLCA) to chenodeoxycholic acid (CDCA) and minor amounts of ursodeoxycholic acid (UDCA). Here, we provide evidence from in vitro and in vivo studies for a major role of 11ß-HSD1 in the oxidoreduction of 7-oxoLCA and compare its level and metabolism in several species. Hepatic microsomes from liver-specific 11ß-HSD1-deficient mice were devoid of 7-oxoLCA oxidoreductase activity. Importantly, circulating and intrahepatic levels of 7-oxoLCA and its taurine conjugate were significantly elevated in mouse models of 11ß-HSD1 deficiency. Moreover, comparative enzymology of 11ß-HSD1-dependent oxidoreduction of 7-oxoLCA revealed that the guinea-pig enzyme is devoid of 7-oxoLCA oxidoreductase activity. Unlike in other species, 7-oxoLCA and its glycine conjugate are major bile acids in guinea-pigs. In conclusion, the oxidoreduction of 7-oxoLCA and its conjugated metabolites are catalyzed by 11ß-HSD1, and the lack of this activity leads to the accumulation of these bile acids in guinea-pigs and 11ß-HSD1-deficient mice. Thus, 7-oxoLCA and its conjugates may serve as biomarkers of impaired 11ß-HSD1 activity.

Lithocholic acid disrupts phospholipid and sphingolipid homeostasis leading to cholestasis in mice.

UNLABELLED: Lithocholic acid (LCA) is an endogenous compound associated with hepatic toxicity during cholestasis. LCA exposure in mice resulted in decreased serum lysophosphatidylcholine (LPC) and sphingomyelin levels due to elevated lysophosphatidylcholine acyltransferase (LPCAT) and sphingomyelin phosphodiesterase (SMPD) expression. Global metabolome analysis indicated significant decreases in serum palmitoyl-, stearoyl-, oleoyl-, and linoleoyl-LPC levels after LCA exposure. LCA treatment also resulted in decreased serum sphingomyelin levels and increased hepatic ceramide levels, and induction of LPCAT and SMPD messenger RNAs (mRNAs). Transforming growth factor-ß (TGF-ß) induced Lpcat2/4 and Smpd3 gene expression in primary hepatocytes and the induction was diminished by pretreatment with the SMAD3 inhibitor SIS3. Furthermore, alteration of the LPCs and Lpcat1/2/4 and Smpd3 expression was attenuated in LCA-treated farnesoid X receptor-null mice that are resistant to LCA-induced intrahepatic cholestasis. CONCLUSION: This study revealed that LCA induced disruption of phospholipid/sphingolipid homeostasis through TGF-ß signaling and that serum LPC is a biomarker for biliary injury.

Effect of probiotics on serum bile acids in patients with ulcerative colitis.

BACKGROUND/AIMS: Evaluation of bile acids (BA) is useful for assessing the changes of intestinal flora in patients with ulcerative colitis (UC). During enterohepatic circulation, the intestinal micro flora cause 7 alpha-dehydroxylation of cholic acid (CA) and chenodeoxycholic acid (CDCA), yielding deoxycholic acid(DCA) and lithocholic acid, respectively. The aim of the present study was to investigate the effects of probiotics in patients with UC by examining changes of the serum BA profile. METHODOLOGY: Twenty-seven patients were divided into the following 2 groups based on endoscopic findings: Fifteen patients with distal UC (dUC group) and 12 patients with pancolitis (pUC group). After treatment with mesalazine or salazosulfapyridine (5-ASA), all patients achieved remission. Then they were given 5-ASA plus the probiotic Clostridium butyricum Miyairi (3.0 g/day) for 4 weeks. RESULTS: After 4 weeks of probiotic treatment, %CDCA was significantly higher and %DCA was significantly lower in the pUC group than in the HV group. In contrast, the dUC group showed no significant differences of %CDCA or %DCA from the HV group after 4 weeks. CONCLUSIONS: Probiotic therapy restored intestinal flora involved in 7 alpha-dehydroxylation in the dUC group, but not in the pUC group.

High-dose ursodeoxycholic acid is associated with the development of colorectal neoplasia in patients with ulcerative colitis and primary sclerosing cholangitis.

OBJECTIVES: Some studies have suggested that ursodeoxycholic acid (UDCA) may have a chemopreventive effect on the development of colorectal neoplasia in patients with ulcerative colitis (UC) and primary sclerosing cholangitis (PSC). We examined the effects of high-dose (28-30 mg/kg/day) UDCA on the development of colorectal neoplasia in patients with UC and PSC. METHODS: Patients with UC and PSC enrolled in a prior, multicenter randomized placebo-controlled trial of high-dose UDCA were evaluated for the development of colorectal neoplasia. Patients with UC and PSC who received UDCA were compared with those who received placebo. We reviewed the pathology and colonoscopy reports for the development of low-grade or high-grade dysplasia or colorectal cancer. RESULTS: Fifty-six subjects were followed for a total of 235 patient years. Baseline characteristics (including duration of PSC and UC, medications, patient age, family history of colorectal cancer, and smoking status) were similar for both the groups. Patients who received high-dose UDCA had a significantly higher risk of developing colorectal neoplasia (dysplasia and cancer) during the study compared with those who received placebo (hazard ratio: 4.44, 95% confidence interval: 1.30-20.10, P=0.02). CONCLUSIONS: Long-term use of high-dose UDCA is associated with an increased risk of colorectal neoplasia in patients with UC and PSC.

Bile acid changes after high-dose ursodeoxycholic acid treatment in primary sclerosing cholangitis: Relation to disease progression.

UNLABELLED: High-dose (28-30 mg/kg/day) ursodeoxycholic acid (UDCA) treatment improves serum liver tests in patients with primary sclerosing cholangitis (PSC) but does not improve survival and is associated with increased rates of serious adverse events. The mechanism for the latter undesired effect remains unclear. High-dose UDCA could result in the production of hepatotoxic bile acids, such as lithocholic acid (LCA), because of limited small bowel absorption of UDCA and conversion of UDCA by bacteria in the colon. We determined the serum bile acid composition in 56 patients with PSC previously enrolled in a randomized, double-blind controlled trial of high-dose UDCA versus placebo. Samples for analysis were obtained at the baseline and at the end of treatment. The mean changes in the UDCA level (16.86 versus 0.05 micromol/L) and total bile acid level (17.21 versus -0.55 micromol/L) were significantly higher in the UDCA group (n = 29) versus the placebo group (n = 27) when pretreatment levels were compared (P < 0.0001). LCA was also markedly increased (0.22 versus 0.01 micromol/L) in the UDCA group compared to the placebo group (P = 0.001). No significant changes were detected for cholic acid, deoxycholic acid, or chenodeoxycholic acid. Patients (n = 9) in the UDCA group who reached clinical endpoints of disease progression (the development of cirrhosis, varices, liver transplantation, or death) tended to have greater increases in their posttreatment total bile acid levels (34.99 versus 9.21 micromol/L, P < 0.08) in comparison with those who did not. CONCLUSION: High-dose UDCA treatment in PSC patients results in marked UDCA enrichment and significant expansion of the total serum bile acid pool, including LCA.

Oral gavage of nano-encapsulated conjugated acrylic acid-bile acid formulation in type 1 diabetes altered pharmacological profile of bile acids, and improved glycaemia and suppressed inflammation.

BACKGROUND: Ursodeoxycholic acid (UDCA) is a secondary hydrophilic bile acid, metabolised in the gut, by microbiota. UDCA is currently prescribed for primary biliary cirrhosis, and of recently has shown ß-cell protective effects, which suggests potential antidiabetic effects. Thus, this study aimed to design targeted-delivery microcapsules for oral uptake of UDCA and test its effects in type 1 diabetes (T1D). METHODS: UDCA microcapsules were produced using alginate-NM30 matrix. Three equal groups of mice (6-7 mice per group) were gavaged daily UDCA powder, empty microcapsules and UDCA microcapsules for 7 days, then T1D was induced by alloxan injection and treatments continued until mice had to be euthanised due to weight loss > 10% or severe symptoms develop. Plasma, tissues, and faeces were collected and analysed for bile acids' concentrations. RESULTS: UDCA microcapsules brought about reduction in elevated blood glucose, reduced inflammation and altered concentrations of the primary bile acid chenodeoxycholic acid and the secondary bile acid lithocholic acid, without affecting survival rate of mice. CONCLUSION: The findings suggest that UDCA exerted direct protective effects on pancreatic ß-cells and this is likely to be associated with alterations of concentrations of primary and secondary bile acids in plasma and tissues. Three equal groups of mice were gavaged daily UDCA (ursodeoxycholic acid) powder, empty microcapsules and UDCA microcapsules for 7 days, then T1D was induced and treatments continued until mice had to be euthanised. UDCA microcapsules brought about reduction in elevated blood glucose, reduced inflammation and altered concentrations of the primary bile acid chenodeoxycholic acid and the secondary bile acid lithocholic acid, without affecting survival rate of mice. The findings suggest that UDCA exerted direct protective effects on pancreatic ß-cells and this is likely to be associated with alterations of concentrations of primary and secondary bile acids in plasma and tissues.

Effect of Rifampicin on the Plasma Concentrations of Bile Acid-O-Sulfates in Monkeys and Human Liver-Transplanted Chimeric Mice With or Without Bile Flow Diversion.

The present study examined the significance of enterohepatic circulation and the effect of rifampicin [an inhibitor of organic anion-transporting polypeptide 1B (OATP1B)] on the plasma concentrations of bile acid-O-sulfates (glycochenodeoxycholate-O-sulfate, lithocholate-O-sulfate, glycolithocholate-O-sulfate, and taurolithocholate-O-sulfate) in monkeys and human liver-transplanted chimeric mice (PXB mouse). Rifampicin significantly increased the area under the curve of bile acid-O-sulfates in monkeys (13-69 times) and PXB mice (13-25 times) without bile flow diversion. Bile flow diversion reduced the concentration of plasma bile acid-O-sulfates under control conditions in monkeys and the concentration of plasma glycochenodeoxycholate-O-sulfate in PXB mice. It also diminished diurnal variation of plasma lithocholate-O-sulfate, glycolithocholate-O-sulfate, and taurolithocholate-O-sulfate in PXB mice under control conditions. Bile flow diversion did not affect the plasma concentration of bile acid-O-sulfates in monkeys and PXB mice treated with rifampicin. Plasma coproporphyrin I and III levels were constant in monkeys throughout the study, even with bile flow diversion. This study demonstrated that bile acid-O-sulfates are endogenous OATP1B biomarkers in monkeys and PXB mice. Enterohepatic circulation can affect the baseline levels of plasma bile acid-O-sulfates and modify the effect of OATP1B inhibition.

Removing substances from blood by affinity chromatography. I. Removing bilirubin and other albumin-bound substances from plasma and blood with albumin-conjugated agarose beads.

Substances such as bilirubin that bind tightly to plasma proteins cannot readily be removed from blood. We describe here the use of affinity chromatography as a new approach to the removal of proteinbound metabolites and toxins from blood. Agarose beads were coupled via cyanogen bromide to human serum albumin so as to contain 30-50 mg of albumin/g wet wt. Such beads, when exposed to plasma from a patient with congenital nonhemolytic jaundice labeled with [(14)C]-bilirubin, bound more than 150 mug bilirubin/g of beads. The binding was saturable, concentration-dependent, relatively independent of flow rate, and reversible by elution with plasma, albumin, or 50% (vol/vol) ethanol. The beads could be repeatedly reused without loss of efficiency after ethanol elution and long storage in the cold. Salicylate, cortisol, and taurocholate, which bind weakly to albumin, were retarded by the beads but eluted with neutral buffer. Thyroxine, taurolithocholate, chenodeoxycholate, and digitoxin bound tightly but were eluted with 50% ethanol. Digoxin did not bind at all. When whole blood was passed over agarose-albumin beads, bilirubin was removed, calcium and magnesium fell slightly, but red cells, white cells, platelets, clotting factors, and a variety of electrolytes and proteins were substantially unchanged. Agarose-albumin beads may be useful for removing protein-bound substances from the blood of patients with liver failure, intoxication with protein-bound drugs, or specific metabolic deficits. Furthermore, it may be possible to make useful adsorbents by attaching other proteins to agarose or other polymer beads.

Biomarkers of unstable angina pectoris and yangxin decoction intervention: An exploratory metabonomics study of blood plasma.

BACKGROUND: This study aimed to explore the related metabolic biomarkers and to observe the effects of Yangxin Decoction (YXD) on plasma metabolism of patients with unstable angina (UA). METHODS: In total, 10 patients with UA (intervention group) and 10 healthy participants (control group) were recruited for this study from January 2009 to December 2010. Plasma samples from both groups were analyzed using liquid chromatography mass spectrometry (LC-MS). Principle component analysis (PCA) and partial least squares (PLS) were used to explore the correlations between metabolic markers in patients with UA. RESULTS: The LC-MS results indicated that the serum levels of 5 potential metabolic markers, namely, ceramide, glycocholic acid, allocholic acid, lithocholic acid, and leukotriene (LT) B4, were significantly higher in the intervention group than those in the control group. CONCLUSION: The results of this study demonstrated potential metabolic markers that can be used to distinguish and diagnose patients with UA.

Bile acid metabolism in extrahepatic biliary atresia: lithocholic acid in stored dried blood collected at neonatal screening.

Lithocholic acid (LCA) is a potent hepatotoxic compound. Fetal LCA may have a role in the pathogenesis of neonatal cholestasis/extrahepatic biliary atresia (EHBA). Fetal liver efficiently hydroxylates LCA in several positions. This may represent a detox-ification mechanism. In the present study LCA, cholic acid (CA) and chenodeoxycholic acid (CDCA) were quantitated by gas chromatography-mass spectrometry using selected ion monitoring in small amounts of stored dried blood from six newborn infants with EHBA and fourteen con-trols. The blood was collected at neonatal metabolic screening. Mean blood levels (+/- S.E.M.) of LCA were 0.11 +/- 0.04 microM in the in-fants with EHBA and 0.08 +/- 0.02 microM in the control infants. The correspon-ding levels for CA and CDCA were 15.6 +/- 3.6 microM and 7.4 +/- 2.5 microM in the infants with EHBA and 1.7 +/- 0.3 microM and 1.8 +/- 0.4 microM in the controls. The increased levels of CA and CDCA in the infants with liver disease can be explained by cholestasis. The low blood levels of LCA indicate a normal fetal metabolism of this bile acid in EHBA.

Oxidative stress markers, secondary bile acids and sulfated bile acids classify the clinical liver injury type: Promising diagnostic biomarkers for cholestasis.

Clinicians sometimes encounter difficulty in choosing a therapeutic strategy due to the uncertainty regarding the type of liver injury. In particular, cholestasis is difficult to diagnose by conventional markers at an early stage of disease. The aim of this study was to identify promising biomarkers for distinguishing the symptom-based types of liver injury (e.g. hepatocellular injury, cholestasis), which was derived from a rigorously statistical perspective. The associations between diagnostic biomarkers (e.g. bile acid components, oxidative stress markers and liver fibrosis markers) and the liver injury types were assessed by a multiple logistic regression analysis using 304 blood samples from patients with liver disease. As a result, reductions in the lithocholic acid (LCA) and deoxycholic acid (DCA) levels, and elevation of the serum sulfated bile acid (SSBA), liver fibrosis marker IV collagen (type IV collagen), hyaluronic acid (HA) and reactive oxygen species (ROS) levels were all significantly associated with cholestasis. On the other hand, elevations in the LCA and type IV collagen levels, and a reduction in the ursodeoxy cholic acid (UDCA) level, were significantly associated with hepatocellular injury. The receiver operating characteristic (ROC) analyses showed that the largest area under the ROC curve (AUC) was found for ROS, followed by DCA, HA, LCA, SSBA and type IV collagen in the cholestatic-type cases. These results indicated that ROS, the secondary bile acid levels such as DCA and LCA, and SSBA are promising biomarkers for cholestasis and for classifying the type of liver injuries. This comprehensive approach will allow for an accurate diagnosis, which will facilitate the selection of an appropriate therapy at the onset of disease.

Concentration of unsulfated lithocholic acid in portal and systemic venous plasma: evidence that lithocholic acid does not down regulate the hepatic cholesterol 7 alpha-hydroxylase activity in gallstone patients.

It has been proposed that lithocholic acid may have a physiological role for the regulation of bile acid synthesis in humans. In this study, the portal concentration and hepatic uptake of unsulfated lithocholic acid was determined in 21 gallstone patients-untreated, cholestyramine-treated and chenodeoxycholic acid-treated-at cholecystectomy. Lithocholic acid was analyzed by a combined gas-liquid mass-fragmentographic technique. In most of the patients a liver biopsy was obtained for assay of the cholesterol 7 alpha-hydroxylase activity. The portal venous concentration of unsulfated lithocholic acid averaged 0.32 mumol/l in untreated patients, constituting about 4% of the total bile acids. The apparent hepatic uptake of lithocholic acid averaged 78%, being as high as that of cholic acid. No significant correlation was obtained between the portal venous concentration of unsulfated lithocholic acid and the hepatic cholesterol 7 alpha-hydroxylase activity. This study thus confirms an enterohepatic circulation of lithocholic acid in humans. No evidence was obtained that the portal venous inflow of small amounts of lithocholic acid to the liver is of regulatory importance for the cholesterol 7 alpha-hydroxylase activity.

Increased cholesterol and decreased fluidity of red cell membranes (spur cell anemia) in progressive intrahepatic cholestasis.

Progressive hemolytic anemia occurred in a 4 1/2-year-old girl with familial intrahepatic cholestasis; a peripheral smear contained bizarre spiculated "spur" red cells. Analysis of this patient's fresh red cells revealed a 59% increase in cholesterol content with a normal phospholipid content and therefore an increase in the cholesterol/phospholipid molar ratio to 1.35 (normal = 0.92). A similar abnormality of lipid composition was present in serum lipoproteins. The lipid abnormality in red cell membrane was associated with a decrease in membrane fluidity, as assessed by the fluorescence polarization of the hydrophobic probe 1,6-diphenyl-1,3,5-hexatriene. Following incubation with patient's plasma, normal cells acquired a spur-shaped morphology with an associated decrease in osmotic fragility and a 25% increase in cholesterol content. The patient's cells, during incubation with normal plasma, acquired morphologic features of spiculated spherocytes with an increase in osmotic fragility and a 21% decrease in cholesterol content. Chenodeoxycholate and lithocholate were present in markedly elevated concentrations in serum. These studies show that a process identical to spur cell anemia in alcoholic cirrhosis may accompany severe liver disease in children with intrahepatic cholestasis.

Quantitative determination of individual non-sulfated bile acids and sulfated lithocholic acid in serum by mass fragmentography.

Individual non-sulfated bile acids and sulfated lithocholic acid in serum were determined by mass fragmentography. A hexafluoroisopropyl ester-trifluoroacetyl derivative of bile acid was prepared by the method of Imai et al. (J. Chromatogr. 120, 181, 1976). Deuterium labeled deoxycholic acid was used as an internal standard monitoring at m/z 623. Lithocholic acid, deoxycholic acid, chenodeoxycholic acid, ursodeoxycholic acid, and cholic acid were determined by monitoring the intensities of m/z 622, m/z 620, m/z 620, m/z 620, ad m/z 618, respectively. A serum sample of 200 microliters including 500 ng of internal standard was hydrolyzed with strong alkali, then acidified to pH 1 with 2N HCl under cooling on ice, and extracted with diethyl ether immediately. Ether extracts were derivatized without further purification. Besides this assay of non-sulfated bile acids, total serum lithocholic acid including the sulfated form was determined as follows: extraction was performed after mixing the acidified (pH 1 with 2 N HCl) hydrolysate with ether and incubation at 40 degrees C for 2 h. Bile acid peaks in the mass fragmentogram were not affected by other materials in these serum extracts. The average values of individual non-sulfated bile acids in sera from healthy fasting subjects (n=15) were as follows: lithocholic acid, 0.049 micrograms/ml; deoxycholic acid, 0.462 micrograms/ml; chenodeoxycholic acid, 0.671 micrograms/ml; ursodeoxycholic acid, 0.070 icrograms/ml; and cholic acid, 0.217 micrograms/ml. Total lithocholic acid (non-sulfated and sulfated) in sera was 0.166 microgram/ml.

Serum bile acid analysis.

Routine and research techniques are outlined for the analysis of bile acids in serum. The basis of these techniques is the use of liquid-solid extraction and liquid-gel chromatography coupled with the measurement of bile acids by gas chromatography using high resolution glass capillary columns and mass spectrometry which provides increased sensitivity compared with conventional methods of measurement. Problems associated with the isolation and purification of bile acids from serum are discussed and rapid and flexible methods for their metabolic profiling are described. The advantages and applicability of these procedures are illustrated with examples of profiles of bile acids in the serum from normal subjects, patients with liver disease and a patient with an ileal resection.

A radioimmunoassay for lithocholic acid conjugates in human serum and liver tissue.

A sensitive and specific radioimmunoassay for glycine and taurine conjugates of lithocholic acid (CLCA) has been developed. 3H-glycolithocholic acid (S.A. = 17Ci/mmol) was used as tracer. Separation of free from antibody-bound bile acid was carried out using ammonium sulphate (saturated solution). The antiserum showed high specificity for both glyco and tauro conjugated lithocholate (100% cross reaction) and lithocholic acid (25% cross reaction). The sensitivity of the assay (1 pmole/tube), was adequate for measuring CLCA in peripheral blood and hepatic tissue in man.

Cyclosporin A-mediated cholestasis in patients with chronic hepatitis after heart transplantation.

Viral chronic hepatitis often occurs in heart transplant recipients receiving cyclosporin. This essential immunosuppressive drug may induce cholestasis. We investigated the effect of treatment with cyclosporin on serum conjugated bile acids in patients with chronic hepatitis developing after heart transplantation. Fifty-nine patients were studied: 17 with chronic hepatitis, 15 heart transplant patients with normal alanine aminotransferase activity, and 27 heart transplant patients with chronic hepatitis, the last two groups receiving cyclosporin. Hepatic biochemical tests and total bile acid concentration were determined on fasting blood samples. The individual glyco- and tauroconjugated bile acids were quantified by high-performance liquid chromatography and direct spectrometry. In patients taking cyclosporin the bilirubin concentration and the alkaline phosphatase activity were increased only when hepatitis was present, in association with a slight increase in cholic acid level (5.13 microM vs. 0.68 microM; P < 0.01). Conjugated lithocholate concentration was dramatically higher when hepatitis and immunosuppression with cyclosporin were associated (1.17 microM vs. 0.03 and 0.04 microM; P < 0.01). Chenodeoxycholate was the main circulating bile acid only in the heart transplant patients treated with cyclosporin but without hepatitis. These results suggest that the mechanisms which explain the cyclosporin-associated modifications of the bile acid pool are different according to the presence or absence of hepatitis. The occurrence of hepatitis in patients on cyclosporin led to an increase in serum lithocholate and primary bile acid concentrations. Further studies are required to assess the effect of ursodeoxycholic acid for this cholestasis.

Evaluation of enzymic and radioimmunoassay methods for measuring serum bile acids.

Serum bile acids were measured in control subjects and in 23 patients with cirrhosis or cholestasis using an enzymic method which measures total non-sulphated bile acids and 2 commercially available radioimmunoassay methods which measure cholylglycine (CG) and sulpholithocholylglycine (SLCG) respectively. All 3 methods gave abnormal values in patients with cholestasis. In cirrhosis the CG method gave abnormal values more often than the enzymic method. The SLCG method was much less sensitive. Measurement of CG in 2 postprandial samples per patient detected only one patient with normal fasting but abnormal postprandial levels. Analysis of samples by gas liquid chromatography (GLC) showed that the enzymic and CG methods gave a good estimation of total non-sulphated bile acids and cholic acid respectively. Values determined by the SLCG method were much higher than the equivalent GLC values. The CG method is faster than the enzymic method and is less expensive provided sample are analysed in sufficiently large batches.