Berberine alters gut microbial function through modulation of bile acids.

BACKGROUND: Berberine (BBR) is a plant-based nutraceutical that has been used for millennia to treat diarrheal infections and in contemporary medicine to improve patient lipid profiles. Reduction in lipids, particularly cholesterol, is achieved partly through up-regulation of bile acid synthesis and excretion into the gastrointestinal tract (GI). The efficacy of BBR is also thought to be dependent on structural and functional alterations of the gut microbiome. However, knowledge of the effects of BBR on gut microbiome communities is currently lacking. Distinguishing indirect effects of BBR on bacteria through altered bile acid profiles is particularly important in understanding how dietary nutraceuticals alter the microbiome. RESULTS: Germfree mice were colonized with a defined minimal gut bacterial consortium capable of functional bile acid metabolism (Bacteroides vulgatus, Bacteroides uniformis, Parabacteroides distasonis, Bilophila wadsworthia, Clostridium hylemonae, Clostridium hiranonis, Blautia producta; B4PC2). Multi-omics (bile acid metabolomics, 16S rDNA sequencing, cecal metatranscriptomics) were performed in order to provide a simple in vivo model from which to identify network-based correlations between bile acids and bacterial transcripts in the presence and absence of dietary BBR. Significant alterations in network topology and connectivity in function were observed, despite similarity in gut microbial alpha diversity (P = 0.30) and beta-diversity (P = 0.123) between control and BBR treatment. BBR increased cecal bile acid concentrations, (P < 0.05), most notably deoxycholic acid (DCA) (P < 0.001). Overall, analysis of transcriptomes and correlation networks indicates both bacterial species-specific responses to BBR, as well as functional commonalities among species, such as up-regulation of Na+/H+ antiporter, cell wall synthesis/repair, carbohydrate metabolism and amino acid metabolism. Bile acid concentrations in the GI tract increased significantly during BBR treatment and developed extensive correlation networks with expressed genes in the B4PC2 community. CONCLUSIONS: This work has important implications for interpreting the effects of BBR on structure and function of the complex gut microbiome, which may lead to targeted pharmaceutical interventions aimed to achieve the positive physiological effects previously observed with BBR supplementation.

Use of dried urine spots for screening of inborn errors of bile acid synthesis.

BACKGROUND: In pediatric patients with cholestasis of unknown cause, inborn errors of bile acid (BA) synthesis (IEBAS) may be considered. For the initial screening for IEBAS, clarification of the urine BA profile is essential. The transportation of urine in a frozen state via air delivery, however, is laborious and costly. This study assessed the feasibility of using dried urine spots (DUS) to establish a more convenient and affordable method of IEBAS screening. METHODS: We created DUS using urine samples from patients with 3ß-hydroxy-Δ5-C27-steroid dehydrogenase/isomerase deficiency (3ß-HSD) and Δ4-3-oxo-steroid 5ß-reductase deficiency as standard preparations. We started accepting DUS specimens by regular mail. RESULTS: The ratio of unusual to usual BA is essential for the initial detection of IEBAS, and the recovery rates of abnormal BA were acceptable. The recovery rate of Δ4-BA on day 28 decreased to 31.8% at 25°C, and to 19.6% at 37°C. Therefore, the sending of DUS should be avoided under conditions of high temperature. Of a total of 49 children with cholestasis, eight new patients were diagnosed with IEBAS using this screening method. CONCLUSION: The mailing screening system is expected to facilitate the shipment, from regions outside of Japan, of samples for IEBAS screening.

Studies on the Unusual 1ß-Hydroxylated Bile Acid Biosynthesis in Infants.

Unusual bile acids (1ß-hydroxylated bile acids), particularly 1ß-hydroxyl-cholic acid (CA-1ß-ol) and 1ß-hydroxyl-chenodeoxycholic acid (CDCA-1ß-ol), have been detected in the urine of infants. These acids are conjugated with amino acids, such as taurine, and are then excreted mainly via the urine. CA-1ß-ol and CDCA-1ß-ol are the predominant bile acids during infancy and are present in relatively large amounts in the urine. However, the biosynthetic pathway of 1ß-hydroxylated bile acids in infants remains unclear. To investigate the biosynthetic pathway of 1ß-hydroxylated bile acids during infancy, we performed a metabolic reaction using infant hepatocytes at 3 months after delivery. Glyco- and tauro-CA-1ß-ol were identified by LC/tandem mass spectrometry (MS/MS) analysis of the extracted culture medium incubated with cholic acids (CAs). Further, we identified that ketoconazole suppressed CA 1ß-hydroxylation and that the CYP3A subfamily was the primary group of enzymes responsible for CA-1ß-ol formation. The present study provides new information about the biosynthetic pathway of 1ß-hydroxylated bile acids during infancy.

Distinguishing primary from secondary Δ(4) -3-oxosteroid 5ß-reductase (SRD5B1, AKR1D1) deficiency by urinary steroid analysis.

OBJECTIVE: Deficiency of Δ(4) -3-oxosteroid 5ß-reductase (5ß-reductase), a bile acid synthesis disorder, presents findings of neonatal cholestasis and hyper-3-oxo-Δ(4) bile aciduria. The 5ß-reductase enzyme participates in not only bile acid synthesis but also hepatic steroid metabolism. Deficiency of 5ß-reductase includes 2 types: primary deficiency, with an SRD5B1 gene mutation; and secondary deficiency, lacking a mutation. Secondary deficiency is caused by fulminant liver failure from various aetiologies including neonatal hemochromatosis (NH). Distinguishing primary from secondary deficiency based on γ-glutamyltransferase (GGT), serum total bile acids (TBA), and urinary bile acid analysis using gas chromatography-mass spectroscopy (GC-MS) is very difficult. SRD5B1 gene analysis is the only reliable method. We examined urinary steroid analysis as a way to distinguish primary from secondary 5ß-reductase deficiency. DESIGN, PATIENTS AND MEASUREMENTS: We examined 12 patients with cholestatic jaundice, normal or slightly elevated GGT, and hyper-3-oxo-Δ(4) bile aciduria using urinary steroid analysis by GC-MS of both cortisol and cortisone compounds, such as 5ß-tetrahydrocortisol (5ß-THF) and 5ß-tetrahydrocortisone (5ß-THE). Patients previously were diagnosed with primary 5ß-reductase deficiency (n = 3), deficiency secondary to NH (n = 3) and deficiency secondary to other liver disorders (n = 6). RESULTS: Urinary steroid analysis in 3 primary deficiency and 3 NH patients showed low 5ß-THE and elevated 5α/5ß-THE ratios, making distinction difficult without also considering the clinical course and abdominal magnetic resonance imaging (MRI) findings, such as a very low signal intensity in liver and/or pancreas, especially in T2 -weighted images. In the six patients with other secondary deficiencies, urinary 5ß-THF and 5α/5ß-THF differed from those in primary deficiency (P < 0·05). CONCLUSIONS: Urinary steroid analysis can distinguish primary and NH-related deficiencies from other secondary deficiencies.

A simple and accurate HPLC method for fecal bile acid profile in healthy and cirrhotic subjects: validation by GC-MS and LC-MS.

We have developed a simple and accurate HPLC method for measurement of fecal bile acids using phenacyl derivatives of unconjugated bile acids, and applied it to the measurement of fecal bile acids in cirrhotic patients. The HPLC method has the following steps: 1) lyophilization of the stool sample; 2) reconstitution in buffer and enzymatic deconjugation using cholylglycine hydrolase/sulfatase; 3) incubation with 0.1 N NaOH in 50% isopropanol at 60°C to hydrolyze esterified bile acids; 4) extraction of bile acids from particulate material using 0.1 N NaOH; 5) isolation of deconjugated bile acids by solid phase extraction; 6) formation of phenacyl esters by derivatization using phenacyl bromide; and 7) HPLC separation measuring eluted peaks at 254 nm. The method was validated by showing that results obtained by HPLC agreed with those obtained by LC-MS/MS and GC-MS. We then applied the method to measuring total fecal bile acid (concentration) and bile acid profile in samples from 38 patients with cirrhosis (17 early, 21 advanced) and 10 healthy subjects. Bile acid concentrations were significantly lower in patients with advanced cirrhosis, suggesting impaired bile acid synthesis.

[Differential diagnosis of primary aldosteronism by measurement of hybrid steroids using mass spectrometry].

Primary aldosteronism (PA), characterized by the autonomous hypersecretion of aldosterone, is the most common cause of secondary hypertension. Patients with PA have a higher risk of cardiovascular morbidity than essential hypertension. The two common subtypes of PA, aldosterone-producing adenoma (APA) and idiopathic hyperaldosteronism (IHA), should be differentiated, because the former is an indication for adrenalectomy, and the latter is treated by medication. 18-Hydroxycortisol and 18-oxocortisol, known as hybrid steroids, have been recognized as markers for the differentiation of aldosterone-producing adenoma and rare glucocorticoid remediable hyperaldosteronism from other subtypes of PA. Hybrid steroids have been measured using immunoassays such as enzyme-linked immunoassays; however, immunoassays for hybrid steroids are not widely used. Recently, liquid chromatography-tandem mass spectrometry (LC-MS/MS) for hybrid steroids was developed. The ability to measure hybrid steroids using LC-MS/MS will be useful for the differential diagnosis of subtypes of PA.

Two neonatal cholestasis patients with mutations in the SRD5B1 (AKR1D1) gene: diagnosis and bile acid profiles during chenodeoxycholic acid treatment.

BACKGROUND AND AIMS: In two Japanese infants with neonatal cholestasis, 3-oxo-Δ(4)-steroid 5ß-reductase deficiency was diagnosed based on mutations of the SRD5B1 gene. Unusual bile acids such as elevated 3-oxo-Δ(4) bile acids were detected in their serum and urine by gas chromatography-mass spectrometry. We studied effects of oral chenodeoxycholic acid treatment. PATIENTS AND METHODS: SRD5B1 gene analysis used peripheral lymphocyte genomic DNA. Diagnosis and treatment of these two patients were investigated retrospectively and prospectively investigated. RESULTS: With respect to SRD5B1, one patient was heterozygous (R266Q, a novel mutation) while the other was a compound heterozygote (G223E/R261C). Chenodeoxycholic acid treatment was effective in improving liver function and decreasing unusual bile acids such as 7α-hydroxy- and 7α,12α-dihydroxy-3-oxo-4-cholen-24-oic acids in serum and urine. CONCLUSION: Primary bile acid treatment using chenodeoxycholic acid was effective for these patients treated in early infancy before the late stage of chronic cholestatic liver dysfunction.

Analysis of triacylglycerol hydroperoxides in human lipoproteins by Orbitrap mass spectrometer.

Herein, we represent a simple method for the detection and characterization of molecular species of triacylglycerol monohydroperoxides (TGOOH) in biological samples by use of reversed-phase liquid chromatography with a LTQ Orbitrap XL mass spectrometer (LC/LTQ Orbitrap) via an electrospray ionization source. Data were acquired using high-resolution, high-mass accuracy in Fourier-transform mode. Platform performance, related to the identification of TGOOH in human lipoproteins and plasma, was estimated using extracted ion chromatograms with mass tolerance windows of 5 ppm. Native low-density lipoproteins (nLDL) and native high-density lipoproteins (nHDL) from a healthy donor were oxidized by CuSO4 to generate oxidized LDL (oxLDL) and oxidized HDL (oxHDL). No TGOOH molecular species were detected in the nLDL and nHDL, whereas 11 species of TGOOH molecules were detected in the oxLDL and oxHDL. In positive-ion mode, TGOOH was found as [M + NH4](+). In negative-ion mode, TGOOH was observed as [M + CH3COO](-). TGOOH was more easily ionized in positive-ion mode than in negative-ion mode. The LC/LTQ Orbitrap method was applied to human plasma and three molecular species of TGOOH were detected. The limit of detection is 0.1 pmol (S/N = 10:1) for each synthesized TGOOH.

Measurement of transport activities of 3ß-hydroxy-Δ(5)-bile acids in bile salt export pump and multidrug resistance-associated proteins using LC-MS/MS.

A method has been developed for the measurement of transport activities in membrane vesicles obtained from Sf9 cells for 3ß-hydroxy-Δ(5)-bile acids by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. Calibration curves for the bile acids were linear over the range of 10 to 2000 pmol/mL, and the detection limit was less than 1 pmol/mL for 3ß-hydroxy-Δ(5)-bile acids using selected reaction monitoring analysis. The analytical method was applied to measurements of transport activities in membrane vesicles obtained from human multidrug resistance-associated protein 2-, 3-, and human bile salt export pump-expressing Sf9 cells for conjugated 3ß-hydroxy-Δ(5)-bile acids. The present study demonstrated that human multidrug resistance-associated protein 3 vesicles accepted conjugated 3ß-hydroxy-Δ(5)-bile acids along with common bile acids such as glycocholic acid and taurolithocholic acid 3-sulfate.

Quantitative determination of phosphatidylcholine hydroperoxides during copper oxidation of LDL and HDL by liquid chromatography/mass spectrometry.

1-Palmitoyl-2-linoleoylphosphatidylcholine monohydroperoxide (PC 16:0/18:2-OOH) and 1-stearoyl-2-linoleoylphosphatidylcholine monohydroperoxide (PC 18:0/18:2-OOH) were measured by liquid chromatography/mass spectrometry (LC/MS) using nonendogenous 1-palmitoyl-2-heptadecenoylphosphatidylcholine monohydroperoxide as an internal standard. The calibration curves for synthetic PC 16:0/18:2-OOH and PC 18:0/18:2-OOH, which were obtained by direct injection of the internal standard into the LC/MS system, were linear throughout the calibration range (0.8-12.8 pmol). Within-day and between-day coefficients of variation were less than 10%, and the recoveries were between 86% and 105%. The limit of detection (LOD) and the limit of quantification (LOQ) were determined using synthetic standards. The LOD (signal-to-noise ratio 3:1) was 0.01 pmol, and the LOQ (signal-to-noise ratio 6:1) was 0.08 pmol for both PC 16:0/18:2-OOH and PC 18:0/18:2-OOH. With use of this method, the concentrations of PC 16:0/18:2-OOH and PC 18:0/18:2-OOH in the lipoprotein fractions during copper-mediated oxidation were determined. We prepared oxLDL and oxHDL by incubating native LDL and native HDL from human plasma (n = 10) with CuSO(4) for up to 4 h. The time course of the PC 16:0/18:2-OOH and PC 18:0/18:2-OOH levels during oxidation consisted of three phases. For oxidized LDL, both compounds exhibited a slow lag phase and a subsequent rapidly increasing propagation phase, followed by a gradually decreasing degradation phase. In contrast, for oxidized HDL, both compounds initially exhibited a prompt propagation phase with a subsequent plateau phase, followed by a rapid degradation phase. The analytical LC/MS method for phosphatidylcholine hydroperoxides might be useful for the analysis of biological samples.

Detection and characterization of cholesteryl ester hydroperoxides in oxidized LDL and oxidized HDL by use of an Orbitrap mass spectrometer.

Oxidation of cholesteryl esters in lipoproteins by reactive oxygen species yields cholesteryl ester hydroperoxides (CEOOH). In this study, we developed a novel method for identification and characterization of CEOOH molecules in human lipoproteins by use of reversed-phase liquid chromatography with an hybrid linear ion trap-Orbitrap mass spectrometer (LC-LTQ Orbitrap). Electrospray ionization tandem mass spectrometric analysis was performed in both positive-ion and negative-ion modes. Identification of CEOOH molecules was completed by use of high-mass-accuracy (MA) mass spectrometric data obtained by using the spectrometer in Fourier-transform (FT) mode. Native low-density lipoproteins (nLDL) and native high-density lipoproteins (nHDL) from a healthy donor were oxidized by CuSO(4), furnishing oxidized LDL (oxLDL) and oxidized HDL (oxHDL). No CEOOH molecules were detected in the nLDL and the nHDL, whereas six CEOOH molecules were detected in the oxLDL and the oxHDL. In positive-ion mode, CEOOH was detected as [M + NH(4)](+) and [M + Na](+) ions. In negative-ion mode, CEOOH was detected as [M + CH(3)COO](-) ions. CEOOH were more easily ionized in positive-ion mode than in negative-ion mode. The LC-LTQ Orbitrap method was applied to human plasma and six species of CEOOH were detected. The limit of detection was 0.1 pmol (S/N = 5:1) for synthesized CEOOH.

Successful heterozygous living donor liver transplantation for an oxysterol 7α-hydroxylase deficiency in a Japanese patient.

Only 2 patients with an oxysterol 7α-hydroxylase deficiency caused by mutations of the cytochrome P450 7B1 (CYP7B1) gene have been reported; for both, the outcome was fatal. We describe the clinical and laboratory features, the hepatic and renal histological findings, and the results of bile acid and CYP7B1 gene analyses for a third patient. This Japanese infant presented with progressive cholestatic liver disease and underwent successful heterozygous living donor liver transplantation. Sources of relevant data included medical records, hepatic and renal histopathological findings, gas chromatography/mass spectrometry analyses of bile acids in serum and urine samples, and analyses of the CYP7B1 gene in the DNA of peripheral blood lymphocytes. Large excesses of 3ß-hydroxy-5-cholen-24-oic acid were detected in the patient's serum and urine. Cirrhosis and polycystic changes in the kidneys were documented. The demonstration of compound heterozygous mutations (R112X/R417C) of the CYP7B1 gene led to the diagnosis of an oxysterol 7α-hydroxylase deficiency. After liver transplantation with an allograft from a heterozygous living donor (the patient's mother), the features of decompensated hepatocellular failure abated, and the renal abnormalities were resolved. In conclusion, we report the first Japanese patient with an oxysterol 7α-hydroxylase deficiency associated with compound heterozygous mutations of the CYP7B1 gene; in this patient, liver transplantation with an allograft from a parental donor was effective.

Liquid chromatography-mass spectrometric determination of plasmalogens in human plasma.

A new liquid chromatography-mass spectrometry (LC/MS) method has been developed for the quantitative analysis of plasmalogens in human plasma using a nonendogenous plasmalogen (1-O-1'-(Z)-tricosenyl-2-oleoyl-rac-glycero-3-phosphocholine, PLS 23:0/18:1) as an internal standard. 1-O-1'-(Z)-Tricosenyl glyceryl ether was prepared by reacting lithioalkoxyallyl with 1-iodoeicosane as the key intermediate in the formation of PLS 23:0/18:1. In LC/MS analyses, PLS 23:0/18:1 generated significant fragment ions in positive and negative modes. In positive ion mode, the [M+H](+) of PLS 23:0/18:1 yielded unique fragments with cleavages at the sn-1 and sn-2 positions of the glycerol backbone. In negative ion mode, the [M+CH(3)COO](-) of PLS 23:0/18:1 resulted in characteristic fragmentation at the sn-2 and sn-3 positions. 1-O-1'-(Z)-Hexadecenyl-2-linoleoyl-rac-glycero-3-phosphocholine (PLS 16:0/18:2) and 2-arachidonoyl-O-1'-(Z)-hexadecenyl-rac-glycero-3-phosphocholine (PLS 16:0/20:4) were chemically synthesized as PLS 23:0/18:1. The calibration curves obtained for PLS 16:0/18:2 and PLS 16:0/20:4 were linear throughout the calibration range (0.04-1.60 pmol). The LOD (S/N = 5:1) was 0.008 pmol and the LOQ (S/N = 6:1) was 0.01 pmol for both PLS 16:0/18:2 and PLS 16:0/20:4. Plasma concentrations of PLS 16:0/18:2 and PLS 16:0/20:4 were 4.0 ± 1.3 µM and 3.5 ± 1.2 µM (mean ± SD), respectively, in five healthy volunteers.

Maternal and fetal circulation of unusual bile acids: a pilot study.

BACKGROUND: Large amounts of unusual bile acids are synthesized by the fetal liver in late gestation. These compounds are mostly transferred from fetus to mother, although some are excreted into the amniotic fluid. We investigated the role of placental transfer of bile acids in fetal bile acid metabolism, particularly with respect to the unusual bile acids (1ß-hydroxylated and ketonic bile acids). METHODS: We measured concentrations of bile acids in umbilical cord blood and urine of newborn infants, and in perinatal maternal serum and urine, using gas chromatography-mass spectrometry. Serum and urine specimens from healthy non-pregnant women were used as controls. RESULTS: In newborn infants at delivery, cord blood and urine contained mostly primary and 1ß-hydroxylated bile acids, respectively. We also detected large amounts of ketonic bile acids in their urine, and the urinary concentration of total bile acids was elevated. Main maternal bile acids at 30 and 35 weeks of gestation and at delivery were 1ß-hydroxylated bile acids. After delivery, main bile acids changed from 1ß-hydroxylated bile acids to primary bile acids (P < 0.03), which also predominated in healthy non-pregnant women. CONCLUSION: Fetally synthesized unusual bile acids were transported from fetus to mother. Pregnant women appear to excrete these bile acids into the urine, lowering both fetal and maternal serum bile acid concentrations.

Molecular genetic and bile acid profiles in two Japanese patients with 3beta-hydroxy-DELTA5-C27-steroid dehydrogenase/isomerase deficiency.

We report definitive diagnosis and effective chenodeoxycholic acid (CDCA) treatment of two Japanese children with 3[beta]-hydroxy-[DELTA]5-C27-steroid dehydrogenase/isomerase deficiency. Findings of cholestasis with normal serum [gamma]-glutamyltransferase activity and total bile acid concentration indicated the need for definitive bile acid analysis. Large amounts of 3[beta]-hydroxy-[DELTA]5 bile acids were detected by gas chromatography-mass spectrometry. HSD3B7 gene analysis using peripheral lymphocyte genomic DNA from the patients and their parents identified four novel mutations of the HSD3B7 gene in the patients. One had a homozygous mutation, 314delA; the other had compound heterozygous mutations: V132F, T149I, and 973_974insCCTGC. Interestingly, the second patient's mother had V132F and T149I mutations in one allele. Excessive 3[beta]-hydroxy-[DELTA]5-bile acids such as 3[beta],7[alpha]-dihydroxy- and 3[beta],7[alpha],12[alpha]-trihydroxy-5-cholenoic acids were detected in the first patient's urine; the second patient's urine contained large amounts of 3[beta]-hydroxy-5-cholenoic acid. Liver dysfunction in both patients decreased with ursodeoxycholic acid treatment, but unusual bile acids were still detected. Normalization of the patients' liver function and improvement of bile acid profiles occurred with CDCA treatment. Thus, we found mutations in the HSD3B7 gene accounting for autosomal recessive neonatal cholestasis caused by 3[beta]-hydroxy-[DELTA]5-C27-steroid dehydrogenase/isomerase deficiency. Early neonatal diagnosis permits initiation of CDCA treatment at this critical time, before the late cholestatic stage.

Developmental pattern of urinary bile acid profile in preterm infants.

BACKGROUND: Bile acid metabolism in preterm infants is yet to be fully characterized. We compared the developmental pattern of urinary bile acid profiles in ten infants born at gestational ages from 25 to 33 weeks with previous data from full-term infants from birth to about 7 months of age. METHODS: Gas chromatography-mass spectrometry was performed on serial samples. RESULTS: Total urinary bile acid concentrations gradually increased until 1 to 2 months of age. After this peak of excretion (30 to 60 micromol/mmol creatinine), total urinary bile acid concentrations gradually decreased to less than 20 micromol/mmol creatinine. The percentage of usual bile acids (mainly cholic acid) relative to total urinary total bile acids gradually deceased from approximately 30% at birth to less than 15% at 7 months of age. On the other hand, 1beta-hydroxylated bile acids (mainly 1beta,3alpha,7alpha,12alpha-tetrahydroxy-5beta-cholan-24-oic acid) relative to total urinary bile acids were increased gradually from 60% at birth to reach 70% to 80% at 1 month of age. The percentage of 1beta-hydroxylated bile acids relative to total urinary bile acids then remained stable at a high percentage (70% to 90%) until the age of 7 months. CONCLUSION: Physiological cholestasis in preterm infants persists longer than in full-term infants. Moreover, as large amounts of cholic and 1beta,3alpha,7alpha,12alpha-tetrahydroxy-5beta-cholan-24-oic acids were detected in urine from preterm infants during this study, the 25-hydroxylation pathway may be particularly important for bile acid synthesis in early preterm infants.

[Measurement of the transport activities of bile salt export pump using chemiluminescence detection method].

Monovalent bile acids, such as taurine- and glycine-conjugated bile acids, are excreted into bile by bile salt export pumps (BSEP, ABCB11). Human BSEP (hBSEP) is physiologically important because it was identified as the gene responsible for the genetic disease: progressive familial intrahepatic cholestasis type 2 (PFIC-2). The evaluation of the inhibitory effect of hBSEP transport activity provides significant information for predicting toxic potential in the early phase of drug development. The role and function of hBSEP have been investigated by the examination of the ATP-dependent transport of radioactive isotopically (RI)-labeled bile acid such as a tritium labeled taurocholic acid, in membrane vesicles obtained from hBSEP-expressing cells. The chemiluminescence detection method using 3alpha-hydroxysteroid dehydrogenase (3alpha-HSD) had been developed for a simple analysis of bile acids in human biological fluids. This method is extremely sensitive and it may be applicable for the measurements of bile acid transport activities by hBSEP vesicles without using RI-labeled bile acid. The present paper deals with an application of the chemiluminescence detection method using 3alpha-HSD with enzyme cycling method to the measurement of ATP-dependent transport activities of taurocholic acid (T-CA) in membrane vesicles obtained from hBSEP-expressing Sf9 cells. Calibration curves for T-CA was linear over the range from 10 to 400 pmol/ml. The values of the kinetic parameters for hBSEP vesicles obtained by the chemiluminescence detection method were comparable with the values of that obtained by liquid chromatography-mass spectrometry method. This assay method was highly useful for the measurements of bile acid transport activities.

Changes in conjugated urinary bile acids across age groups.

Bile acid compositions are known to change dramatically after birth with aging. However, no reports have described the transition of conjugated urinary bile acids from the neonatal period to adulthood, and such findings would noninvasively offer insights into hepatic function. The aim of this study was to investigate differences in bile acid species, conjugation rates, and patterns, and to pool characteristics for age groups. We measured urinary bile acids in spot urine samples from 92 healthy individuals ranging from birth to 58 years old using liquid chromatography tandem mass spectrometry (LC/ESI-MS/MS). Sixty-six unconjugated and conjugated bile acids were systematically determined. After birth, urinary bile acids dramatically changed from fetal (i.e., Δ4-, Δ5-, and polyhydroxy-bile acids) to mature (i.e., CA and CDCA) bile acids. Peak bile acid excretion was 6-8 days after birth, steadily decreasing thereafter. A major change in bile acid conjugation pattern (taurine to glycine) also occurred at 2-4 months old. Our data provide important information regarding transitions of bile acid biosynthesis, including conjugation. The data also support the existence of physiologic cholestasis in the neonatal period and the establishment of the intestinal bacterial flora in infants.

The 'in vivo lifestyle' of bile acid 7α-dehydroxylating bacteria: comparative genomics, metatranscriptomic, and bile acid metabolomics analysis of a defined microbial community in gnotobiotic mice.

The formation of secondary bile acids by gut microbes is a current topic of considerable biomedical interest. However, a detailed understanding of the biology of anaerobic bacteria in the genus Clostridium that are capable of generating secondary bile acids is lacking. We therefore sought to determine the transcriptional responses of two prominent secondary bile acid producing bacteria, Clostridium hylemonae and Clostridium hiranonis to bile salts (in vitro) and the cecal environment of gnotobiotic mice. The genomes of C. hylemonae DSM 15053 and C. hiranonis DSM 13275 were closed, and found to encode 3,647 genes (3,584 protein-coding) and 2,363 predicted genes (of which 2,239 are protein-coding), respectively, and 1,035 orthologs were shared between C. hylemonae and C. hiranonis. RNA-Seq analysis was performed in growth medium alone, and in the presence of cholic acid (CA) and deoxycholic acid (DCA). Growth with CA resulted in differential expression (>0.58 log2FC; FDR < 0.05) of 197 genes in C. hiranonis and 118 genes in C. hylemonae. The bile acid-inducible operons (bai) from each organism were highly upregulated in the presence of CA but not DCA. We then colonized germ-free mice with human gut bacterial isolates capable of metabolizing taurine-conjugated bile acids. This consortium included bile salt hydrolase-expressing Bacteroides uniformis ATCC 8492, Bacteroides vulgatus ATCC 8482, Parabacteroides distasonis DSM 20701, as well as taurine-respiring Bilophila wadsworthia DSM 11045, and deoxycholic/lithocholic acid generating Clostridium hylemonae DSM 15053 and Clostridium hiranonis DSM 13275. Butyrate and iso-bile acid-forming Blautia producta ATCC 27340 was also included. The Bacteroidetes made up 84.71% of 16S rDNA cecal reads, B. wadsworthia, constituted 14.7%, and the clostridia made up <.75% of 16S rDNA cecal reads. Bile acid metabolomics of the cecum, serum, and liver indicate that the synthetic community were capable of functional bile salt deconjugation, oxidation/isomerization, and 7α-dehydroxylation of bile acids. Cecal metatranscriptome analysis revealed expression of genes involved in metabolism of taurine-conjugated bile acids. The in vivo transcriptomes of C. hylemonae and C. hiranonis suggest fermentation of simple sugars and utilization of amino acids glycine and proline as electron acceptors. Genes predicted to be involved in trimethylamine (TMA) formation were also expressed.

SRD5B1 gene analysis needed for the accurate diagnosis of primary 3-oxo-Delta4-steroid 5beta-reductase deficiency.

BACKGROUND AND AIM: We encounter hyper-3-oxo-Delta(4) bile aciduria in patients with severe cholestatic liver disease or fulminant liver failure during the neonatal period. However, simply by bile acid analysis, it is difficult to distinguish hyper-3-oxo-Delta(4) bile aciduria from primary 3-oxo-Delta(4)-steroid 5beta-reductase deficiency. METHODS: To determine whether 3-oxo-Delta(4)-steroid 5beta-reductase (SRD5B1) gene analysis is required for the accurate diagnosis of 3-oxo-Delta(4)-steroid 5beta-reductase deficiency, we evaluated the laboratory data, bile acid analysis and SRD5B1 gene analysis from six patients with hyper-3-oxo-Delta(4) bile aciduria. RESULTS: Based upon the results, four patients who had developed neonatal liver failure were diagnosed as having neonatal hemochromatosis. Two patients with chronic cholestasis were diagnosed as having primary 3-oxo-Delta(4)-steroid 5beta-reductase deficiency by SRD5B1 gene analysis. The SRD5B1 gene in these two patients had a heterozygous mutation, G737A (Gly 223 Glu) in one patient and C217T (Arg 50 stop) in the other. CONCLUSIONS: Based upon our limited data, we conclude that SDR5B1 gene analysis is required for the accurate diagnosis of 3-oxo-Delta(4)-steroid 5beta-reductase deficiency. Moreover, we think that it is important to elucidate whether there is a heterozygous or a compound heterozygous mutation of the SRD5B1 gene in our two patients.