Health-related quality of life in women with endometriosis: psychometric validation of the Endometriosis Health Profile 30 questionnaire using confirmatory factor analysis.

STUDY QUESTION: Which of the competing models of the Endometriosis Health Profile 30 Questionnaire (EHP-30) factor structure is best supported by confirmatory factor analysis (CFA)? SUMMARY ANSWER: Findings support a five-factor first-order model of the EHP-30, thereby lending support to the model originally suggested by the questionnaire developers. WHAT IS KNOWN ALREADY: Endometriosis has a negative impact on quality of life, and measures specifically developed to address this impact, such as the EHP-30, are vital in research and disease management. Previous studies have found different models of the EHP-30 factor structure, and generated uncertainty regarding how to use the questionnaire. CFA can be applied to compare competing factor models and determine the underlying structure of a questionnaire. STUDY DESIGN SIZE DURATION: This cross-sectional multicenter study included 304 women with endometriosis recruited from three different public health service endometriosis clinics (referral centers for treatment of severe endometriosis) and the Danish Endometriosis Patients Association from 2014 to 2015. PARTICIPANTS/MATERIALS SETTING METHODS: Diagnosis of endometriosis was confirmed in medical records for 84.2% and by histology for 66.8% of participants. Questionnaires (the licensed Danish version of the EHP-30) were sent by post two times with a 6- to 12-week interval. CFA was used to examine construct validity and Bland-Altman plots to examine test-retest reliability and the convergent validity with the Short Form 36 version 2. MAIN RESULTS AND THE ROLE OF CHANCE: Response rate was high (87.6%). CFA supported the original first-order five-factor structure of the EHP-30, and thereby, the use of five separate scale-scores in clinical and research practice. Visual inspection of Bland-Altman plots suggested excellent test-retest reliability of the EHP-30 and supported the use of a disease specific quality of life instrument for women with endometriosis. LIMITATIONS REASONS FOR CAUTION: Diagnosis could not be confirmed through histology data in 33.2% of participants. However, subgroup analyses based on women with confirmed histology only, yielded similar results. Data related to menstrual cycle stage and the use of hormonal and pain medication during questionnaire completion were not collected. A larger study, including data from different countries on different continents, would be better designed to exclude potential population bias. WIDER IMPLICATIONS OF THE FINDINGS: EHP-30, with its original five-factor structure, appears to be a valid, stable, and specific quality of life measure for women with endometriosis. It seems easy to understand, quick to administer, and importantly, scoring might be unaffected by cyclical/menstrual pain symptoms related to endometriosis. The finding of a five-factor model from different studies across several countries supports the crosscultural validity of the EHP-30. STUDY FUNDING/COMPETING INTERESTS: This work was supported by the Danish Endometriosis Association, which is a nongovernmental organization run by women with endometriosis and by a scholarship from the Health Research Fund of Central Denmark Region. The authors have no conflicts of interest. TRIAL REGISTRATION NUMBER: The Danish Data Protection Agency (J.nr: 2013-41-2264).

Enzymatic quantification of total serum bile acids as a monitoring strategy for women with intrahepatic cholestasis of pregnancy receiving ursodeoxycholic acid treatment: a cohort study.

OBJECTIVE: To evaluate enzymatic total serum bile acid quantification as a monitoring strategy for women with intrahepatic cholestasis of pregnancy (ICP) treated with ursodeoxycholic acid (UDCA). DESIGN: Cohort. SETTING: One UK university hospital. POPULATION: 29 ICP cases treated with UDCA. METHODS: Serial samples were collected prospectively throughout gestation. Total serum bile acids were measured enzymatically and individual bile acids by high-performance liquid chromatography-tandem mass spectrometry. Data were log-transformed and analysed with random effects generalised least square regression. MAIN OUTCOME MEASURES: The relationship between enzymatic total bile acid measurements and individual bile acid concentrations after UDCA treatment. RESULTS: In untreated women, cholic acid was the principal bile acid (51%) and UDCA concentrations were <0.5%, whereas UDCA constituted 60% (IQR 43-69) of serum bile acids following treatment and cholic acid fell to <20%. Changes in the total bile acid measurement reflected similar alterations in the concentrations of the pathologically elevated bile acids, e.g. a two-fold increase in enzymatic total bile acids is accompanied by approximately a two-fold increase in cholic acid and chenodeoxycholic acid at most UDCA doses (P < 0.001). Most of the effects of UDCA on cholic acid occur in the first week of treatment (60% relative reduction, P = 0.025, 95% CI 0.2-0.9, from 10 micromol/l (4.7-17.6) to 3.5 micromol/l (1.4-7.5). CONCLUSION: Ursodeoxycholic acid becomes the main component of the bile acid measurement after treatment. Enzymatic total bile acid assays are good predictors of both cholic acid and chenodeoxycholic acid, the primary bile acids that are raised prior to treatment. TWEETABLE ABSTRACT: Ursodeoxycholic acid constitutes approximately 60% of the bile acid measurement and reduces pathological cholic acid in treated women.

Arc-like magmas generated by mélange-peridotite interaction in the mantle wedge.

The mechanisms of transfer of crustal material from the subducting slab to the overlying mantle wedge are still debated. Mélange rocks, formed by mixing of sediments, oceanic crust, and ultramafics along the slab-mantle interface, are predicted to ascend as diapirs from the slab-top and transfer their compositional signatures to the source region of arc magmas. However, the compositions of melts that result from the interaction of mélanges with a peridotite wedge remain unknown. Here we present experimental evidence that melting of peridotite hybridized by mélanges produces melts that carry the major and trace element abundances observed in natural arc magmas. We propose that differences in nature and relative contributions of mélanges hybridizing the mantle produce a range of primary arc magmas, from tholeiitic to calc-alkaline. Thus, assimilation of mélanges into the wedge may play a key role in transferring subduction signatures from the slab to the source of arc magmas.

The ileal bile acid transporter inhibitor A4250 decreases serum bile acids by interrupting the enterohepatic circulation.

BACKGROUND: Reabsorption of bile acids from the intestine by ileal bile acid transporter is pivotal for the enterohepatic circulation of BAs and sterol homoeostasis. AIM: To assess tolerability and study, bile acid metabolism in a phase 1 trial with the selective ileal bile acid transporter inhibitor A4250. METHODS: A randomised double-blind, single-ascending dose (SAD) and multiple-ascending-dose study consisting of five cohorts comprising 40 individuals with a single administration of A4250 (0.1, 0.3, 1, 3, or 10 mg) or placebo and three cohorts comprising 24 individuals with a 1-week administration of A4250 (1 or 3 mg once daily or 1.5 mg twice daily) or placebo. For the multiple-ascending-dose study, bile acids were measured by HPLC-MS in plasma and faeces, and fibroblast growth factor 19 (FGF19) and 7α-hydroxy-4-cholesten-3-one (C4) were measured in plasma. RESULTS: No serious adverse events occurred and all participants finished the trial per protocol. At the end of the multiple-ascending-dose study, plasma total bile acids and FGF19 decreased by 47% and 76%, respectively, at 3 mg/day (P < 0.01), and by 15% and 16%, respectively, at 1.5 mg twice daily (P < 0.05). Plasma C4 and faecal bile acids increased at all dose regimens, by 555%, 664%, 292% and 338%, 421%, 420%, respectively (P < 0.01-0.05). The primary bile acids cholic and chenodeoxycholic acids constituted the majority of faecal bile acids in the A4250-treated groups. CONCLUSIONS: A4250 is well tolerated. By blocking ileal bile acid transporter in the terminal ileum, it highly efficiently interrupts the enterohepatic circulation of BAs, and should be of benefit to patients with cholestatic liver diseases. Clinical Trial registration EudraCT 2013-001175-21.

Maternal and fetal outcome in Swedish women with erythropoietic protoporphyria.

BACKGROUND: Painful photosensitivity is characteristic of erythropoietic protoporphyria (EPP). In women, symptoms may be affected by menstrual cycle and pregnancy but very little is known about maternal and fetal outcome. OBJECTIVES: To investigate the impact of menstruation, pregnancy and breast-feeding on photosensitivity and possible effects of EPP on maternal, fetal and neonatal outcome. METHODS: Retrospective study screening all 20 Swedish women alive and older than 18 years diagnosed with EPP with a total of 33 deliveries. Data were retrieved for 19 women and 32 deliveries in medical records and completed by a questionnaire sent to the patients. RESULTS: Photosensitivity worsened in five of 19 (26%) women around menstruation whereas amelioration was reported in 17 of 32 (53%) pregnancies and during 11 of 32 (34%) breast-feeding periods. Fertility rate was normal and there were no maternal or fetal complications apart from minor arterial hypertension in one woman. CONCLUSIONS: The study confirms changes in photosensitivity during menstruation and pregnancy. Amelioration during breast-feeding is a new finding. Pregnancy appears safe without increased risks of pregnancy complications or adverse effects on fetal or neonatal health.

Intrahepatic cholestasis of pregnancy and associated adverse pregnancy and fetal outcomes: a 12-year population-based cohort study.

OBJECTIVE: To determine the risk for adverse pregnancy and fetal outcomes in intrahepatic cholestasis of pregnancy (ICP). DESIGN: Population-based cohort study. SETTING: Swedish Medical Birth Register (MBR) 1997-2009. POPULATION: A total of 1,213,668 singleton deliveries. METHODS: Linkage of Hospital Discharge Register for exposure (ICP; n=5,477) with MBR for covariates. MAIN OUTCOME MEASURES: Gestational diabetes, pre-eclampsia, prematurity, and stillbirth. RESULTS: Intrahepatic cholestasis (ICP) was diagnosed in 0.32-0.58% of all pregnancies, with an increasing trend until 2005 (P<0.0001). Compared with women who did not have ICP, women with ICP were more likely to have gestational diabetes (adjusted odds ratio, aOR, 2.81; 95% CI 2.32-3.41) and pre-eclampsia (aOR 2.62, 95% CI 2.32-2.78). Women with ICP were also more likely to have spontaneous (aOR 1.60, 95% CI 1.47-1.93) and iatrogenic (aOR 5.95, 95% CI 5.23-6.60) preterm delivery, with increased rates of induction of labour (aOR 11.76, 95% CI 11.04-11.62). However, this actively managed cohort of ICP cases was not at increased risk of stillbirth (aOR 0.92, 95% CI 0.52-1.62). Infants in ICP deliveries were more likely to have a low (<7) 5-minute Apgar score (aOR 1.45, 95% CI 1.14-1.85) and be large for gestational age at birth (aOR 2.27, 95% CI 2.02-2.55). CONCLUSIONS: Over time, a greater proportion of Swedish pregnant women have received a diagnosis of ICP, probably because of an increased awareness of the disorder. Our data confirm an increased risk of preterm delivery, but not of stillbirth, in actively managed ICP. The high rates of gestational diabetes and pre-eclampsia are new findings, and need to be considered in the management of ICP pregnancies.

Stereological assessment of placental morphology in intrahepatic cholestasis of pregnancy.

OBJECTIVE: To apply stereology for the detection of possibly morphological abnormalities in placentas of women with intrahepatic cholestasis of pregnancy (ICP). STUDY DESIGN: Prospective case-control study of placentas from untreated and UDCA-treated ICP, respectively, and normal pregnancies, examined for morphological differences by systematic random sampling generated by computerized stereology methodology. MAIN OUTCOME MEASURES: Volume of placenta, surface area of terminal villi and capillaries, volume fraction of collagen, number of syncytial knots, and chorangiosis. RESULTS: Surface area of terminal villi and capillaries, and number of syncytial knots were higher in placentas from all ICP, as compared to controls (p < 0.01). A reduction of collagen was found in placentas from UDCA-treated ICP, both in comparison to placentas from untreated ICP and controls (p < 0.05). CONCLUSION: ICP affects the placenta morphologically as shown by increased terminal villous and capillary surface area, and number of syncytial knots.

Gallstone disease in Swedish twins: risk is associated with ABCG8 D19H genotype.

OBJECTIVE: Recently, variants of the hepatocanalicular cholesterol hemitransporters ABCG5/8 were linked to gallstone disease; ABCG8 D19H in Caucasians and ABCG5 Q604E in Chinese. We investigated these polymorphisms in Swedish twins by merging the Swedish Twin Registry with the Hospital Discharge and Causes of Death Registries for gallstone disease-related diagnoses. DESIGN: All monozygotic (MZ) twins with gallstone disease alive in the Stockholm area were invited to participate. Gallstone disease was defined by entry in all above mentioned registries, questionnaire or abdominal ultrasound. SUBJECTS: ABCG5 Q604E and ABCG8 D19H genotyping was performed in 24 unique MZ and eight dizygotic (DZ) twins from concordant pairs. Screening of the TwinGene database for gallstone disease resulted in an additional 20 concordant MZ and 54 twins from concordant DZ pairs. We included 109 concordantly stone-free MZ and 126 stone-free independent DZ twins as controls. RESULTS: Amongst the 341 twins, 20.8% carried at least one D19H allele as compared to 9.4% of stone-free controls. The association analysis showed that D19H positivity significantly increased the risk of gallstone disease [odds ratio (OR), 2.54; 95% confidence interval (CI), 1.33-4.82; P = 0.004]. We also found a trend for a positive association between gallstone disease and the Q604E variant (OR, 1.47; 95% CI, 1.00-2.16; P = 0.052). CONCLUSION: Twins carrying a heterozygous or homozygous ABCG8 D19H genotype have a significantly increased risk of gallstone disease. Our study confirms the ABCG8 D19H genotype as a major risk factor for gallstone disease.

Contribution of variant alleles of ABCB11 to susceptibility to intrahepatic cholestasis of pregnancy.

BACKGROUND: Intrahepatic cholestasis of pregnancy (ICP) has a complex aetiology with a significant genetic component. ABCB11 encodes the bile salt export pump (BSEP); mutations cause a spectrum of cholestatic disease, and are implicated in the aetiology of ICP. METHODS: ABCB11 variation in ICP was investigated by screening for five mutant alleles (E297G, D482G, N591S, D676Y and G855R) and the V444A polymorphism (c.1331T>C, rs2287622) in two ICP cohorts (n = 333 UK, n = 158 continental Europe), and controls (n = 261) for V444A. PCR primers were used to amplify and sequence patient and control DNA. The molecular basis for the observed phenotypes was investigated in silico by analysing the equivalent residues in the structure of the homologous bacterial transporter Sav1866. RESULTS: E297G was observed four times and D482G once. N591S was present in two patients; D676Y and G855R were not observed. The V444A polymorphism was associated with ICP (allelic analysis for C vs T: OR 1.7 (95% CI 1.4 to 2.1, p<0.001)). In addition, CC homozygotes were more likely to have ICP than TT homozygotes: OR 2.8 (95% CI 1.7 to 4.4 p<0.0001). Structural analyses suggest that E297G and D482G destabilize the protein fold of BSEP. The molecular basis of V444A and N591S was not apparent from the Sav1866 structure. CONCLUSIONS: Heterozygosity for the common ABCB11 mutations accounts for 1% of European ICP cases; these two mutants probably reduce the folding efficiency of BSEP. N591S is a recurrent mutation; however, the mechanism may be independent of protein stability or function. The V444A polymorphism is a significant risk factor for ICP in this population.

Body mass index, alcohol, tobacco and symptomatic gallstone disease: a Swedish twin study.

BACKGROUND/AIMS: Both genetic and environmental factors are involved in the pathogenesis of gallstone disease (GD). We aimed to examine the association between symptomatic GD and overweight (body mass index, BMI, 25-30 kg m(-2)), obesity (BMI > 30 kg m(-2)), alcohol, smoking and smoke-free tobacco by analysing a large twin population. METHODS: The Swedish Twin Registry (STR) was linked to the Swedish Hospital Discharge and Causes of Death Registries for GD and GD-surgery related diagnoses. Weight, height, use of alcohol, smoking and smoke-free tobacco were provided by STR and analysed for possible associations by conditional logistic regression. RESULTS: Overweight and obesity were associated with a significantly higher risk for symptomatic GD in the whole study population (OR 1.86 and OR 3.38; CI: 1.52-2.28 and 2.28-5.02 respectively). High alcohol consumption was associated with a lower risk for GD in the whole population (OR 0.62; CI: 0.51-0.74) with no difference between discordant monozygotic and dizygotic twins (OR 1.08 and OR 0.96; CI: 0.82-1.42 and 0.79-1.16). Smoking or smoke-free tobacco was not correlated with GD. CONCLUSION: Consistent with epidemiological studies, we found positive associations between BMI and the development of symptomatic GD. High alcohol consumption was associated with a decreased risk against GD. Tobacco use has no impact on GD.

Gallstone disease.

Gallstone disease is one of the most prevalent gastrointestinal diseases with a substantial burden to health care systems that is supposed to increase in ageing populations at risk. Aetiology and pathogenesis of cholesterol gallstones still are not well defined, and strategies for prevention and efficient nonsurgical therapies are missing. This review summarizes current concepts on the pathogenesis of cholesterol gallstones with focus on the uptake and secretion of biliary lipids and special emphasis on recent studies into the genetic background.

Intrahepatic cholestasis of pregnancy: the severe form is associated with common variants of the hepatobiliary phospholipid transporter ABCB4 gene.

BACKGROUND: Intrahepatic cholestasis of pregnancy (ICP) is characterised by troublesome maternal pruritus, raised serum bile acid levels and increased fetal risk. Mutations of the ABCB4 gene encoding the hepatobiliary phospholipid transporter have been identified in a small proportion of patients with cholestasis of pregnancy. In a recent prospective study on 693 patients with cholestasis of pregnancy, a cut-off level for serum bile acid (> or =40 micromol/l) was determined for increased risk of fetal complications. OBJECTIVES: To investigate whether common combinations of polymorphic alleles (haplotypes) of the genes encoding the hepatobiliary ATP-binding cassette (ABC) transporters for phospholipids (ABCB4) and bile acids (ABCB11) were associated with this severe form of cholestasis of pregnancy. METHODS: For genetic analysis, 52 women with bile acid levels > or =40 micromol/l (called cases) and 52 unaffected women (called controls) matched for age, parity and geographical residence were studied. Gene variants tagging common ABCB4 and ABCB11 haplotypes were genotyped and haplotype distributions were compared between cases and controls by permutation testing. RESULTS: In contrast with ABCB11 haplotypes, ABCB4 haplotypes differed between the two groups (p = 0.019), showing that the severe form of cholestasis of pregnancy is associated with the ABCB4 gene variants. Specifically, haplotype ABCB4_5 occurred more often in cases, whereas haplotypes ABCB4_3 and ABCB4_7 were more common in controls. These associations were reflected by different frequencies of at-risk alleles of the two tagging polymorphisms (c.711A: odds ratio (OR) 2.27, p = 0.04; deletion intron 5: OR 14.68, p = 0.012). CONCLUSION: Variants of ABCB4 represent genetic risk factors for the severe form of ICP in Sweden.

Hep27, a member of the short-chain dehydrogenase/reductase family, is an NADPH-dependent dicarbonyl reductase expressed in vascular endothelial tissue.

Human Hep27 was originally isolated from growth-arrested HepG2 cells and identified as a member of the superfamily of short-chain dehydrogenases/reductases (SDR). Its substrate specificity has not been determined, but a cross-species comparison suggests that it occurs in widely divergent species, such as human, Cenorhabditis elegans, Drosophila and Arabidopsis thaliana. In this study, Hep27 was expressed as a His(6) fusion protein, and subjected to a substrate screen, using a compound library of SDR substrates, comprising steroids, retinoids, sugars and carbonyl compounds. Whereas no steroid dehydrogenase or retinoid activity was detected, it was found that Hep27 catalyzed the NADPH-dependent reduction of dicarbonyl compounds, like 3,4-hexanedione and 1-phenyl-1,2-propanedione with similar turnover numbers as DCXR (a mitochondrial dicarbonyl reductase/xylulose reductase). In contrast, Hep27 does not convert sugar substrates like xylulose or threose. Based on its substrate specificity and expression in endothelial tissues, it is suggested that Hep27 functions as a dicarbonyl reductase in enzymatic inactivation of reactive carbonyls, involved in covalent modification of cellular components.

Isoursodeoxycholic acid: metabolism and therapeutic effects in primary biliary cirrhosis.

Significant amounts of ursodeoxycholic acid (UDCA) used for the treatment of patients with primary biliary cirrhosis (PBC) become epimerized at C-3 to isoUDCA. We investigated the metabolism of isoUDCA and a possible pharmacologic effect in five patients (51.4 +/- 5.8 years old; 3 females, 2 males) with PBC and persistent elevations of gamma-glutamyl transpeptidase (gamma-GT) and alkaline phosphatase despite treatment with UDCA for more than one year. Serum samples were analyzed for bile acid metabolites and surrogate markers of cholestasis in 4-week intervals after 1 g/d UDCA, wash-out, 0.5 g/d isoUDCA, 0.75 g/d isoUDCA, 0.75 g/d UDCA, and two further periods with 1 g/d UDCA. Bile acids in urine were analyzed after wash-out, 0.5 and 0.75 g/d isoUDCA, and 0.75 and 1 g/d UDCA. During wash-out, AST, AP, and gamma-GT rose significantly (P < 0.05) but reversed to previous levels during the first isoUDCA period, with 0.5 g/d only. No further improvements were observed after increasing the dose of isoUDCA or switching back to UDCA. In serum, the relative amounts of isoUDCA and UDCA were 8.1 +/- 7.4% and 16.2 +/- 6.4% during 0.5 g/d isoUDCA, 6.2 +/- 2.5% and 45.0 +/- 4.1% during 0.75 g/d isoUDCA, and 0.5;-3% and 56.4;-60.0%, respectively, during UDCA. In urine, UDCA was the predominant bile acid both during isoUDCA and UDCA medications. The similar serum enrichment and urinary excretion of UDCA during administration of either isoUDCA or UDCA together with low concentrations of the intermediate of isomerization, 3-dehydro-UDCA, indicate a first-pass epimerization of isoUDCA to UDCA in the liver. Approximately 25% of serum isoUDCA and 10% of serum UDCA were conjugated with either glucuronic acid or N-acetylglucosamine, indicating hepatic formation and systemic secretion of glycosidic conjugates. In PBC patients, isoUDCA becomes isomerized to UDCA and has similar effects on surrogate markers of cholestasis. Thus, isoUDCA has pro-drug characteristics.

Metabolism and effects on cholestasis of isoursodeoxycholic and ursodeoxycholic acids in bile duct ligated rats.

Isoursodeoxycholic acid (isoUDCA), the 3 beta-epimer of ursodeoxycholic acid (UDCA), may have pharmaceutical potential because of its similar hydrophilicity and in vitro cytoprotection as compared with UDCA. We compared metabolism and effects on cholestasis of UDCA and isoUDCA in experimental cholestasis in rats. Cholestasis was induced by bile duct ligation. For bile flow and biliary bile acid analysis, UDCA or isoUDCA were infused intraduodenally. For the study of chronic effects, chow was supplemented with 2.5 g/kg UDCA or isoUDCA for 3 weeks. Sham-operated animals served as controls. IsoUDCA became completely converted to UDCA in the liver. Choleresis and biliary bile acids were the same after the intraduodenal administration of either compound. Oral administration of UDCA or isoUDCA significantly improved liver biochemistry but not clinical and histological parameters in chronic cholestasis. The decrease of serum cholic acid in control animals was more pronounced after isoUDCA (-93%) than after UDCA (-76%). Only after UDCA, this decrease was compensated by increases of UDCA, beta-muricholic acid (MCA), and Delta(22)-beta-MCA. Our results show that isoUDCA has the same effect on choleresis and liver biochemistry as UDCA. IsoUDCA features pro-drug characteristics of UDCA and causes compared to the latter lower serum bile acid concentrations in non-cholestatic animals.

Primary cultures of human hepatocytes but not HepG2 hepatoblastoma cells are suitable for the study of glycosidic conjugation of bile acids.

To define the role of glycosidic conjugation of bile acids in humans, an in vitro model system is desirable. We studied the formation of glycosidic conjugates of bile acids in primary cultures of human hepatocytes, isolated from organ donor liver, and the human hepatoblastoma cell line, HepG2. Cells were incubated with 100 microM bile acids (chenodeoxycholic, CDCA; hyodeoxycholic, HDCA; and isoursodeoxycholic acids, isoUDCA) and 1-2 mM uridine diphosphoglycosides (UDP-glucose, UDP-Glc; UDP-glucuronic acid, UDP-GlcA, and UDP-N-acetylglucosamine, UDP-GlcNAc), and octyl glucoside. Media were analysed by electrospray-/gas chromatography-mass spectrometry and electrospray with collision induced dissociation. Primary cultures of human hepatocytes formed glycosidic bile acid conjugates with UDP-sugars (6alpha-Glc-HDCA, 6alpha-GlcA-HDCA, and 7beta-GlcNAc-isoUDCA) and octyl glucoside as sugar donors (3alpha-Glc-CDCA). HDCA was completely metabolised to either Glc-HDCA, a compound yet not found in vivo, or GlcA-HDCA. No glycosidic bile acid conjugate was found in media from experiments with HepG2. Thus, primary cultures of human hepatocytes, but not HepG2, are suitable in vitro systems for the study of glycosidic bile acid conjugation reactions.