Abnormal urinary bile acids in a patient suffering from cerebrotendinous xanthomatosis during oral administration of ursodeoxycholic acid

Pathophysiology and Treatment of Lipid Abnormalities in Cerebrotendinous Xanthomatosis: An Integrative Review

Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive disorder caused by pathogenic variants in CYP27A1, leading to a deficiency in sterol 27-hydroxylase. This defect results in the accumulation of cholestanol and bile alcohols in various tissues, including the brain, tendons and peripheral nerves. We conducted this review to evaluate lipid profile abnormalities in patients with CTX. A search was conducted in PubMed, Embase and the Virtual Health Library in January 2023 to evaluate studies reporting the lipid profiles of CTX patients, including the levels of cholestanol, cholesterol and other lipids. Elevated levels of cholestanol were consistently observed. Most patients presented normal or low serum cholesterol levels. A decrease in chenodeoxycholic acid (CDCA) leads to increased synthesis of cholesterol metabolites, such as bile alcohols 23S-pentol and 25-tetrol 3-glucuronide, which may serve as surrogate follow-up markers in patients with CTX. Lipid abnormalities in CTX have clinical implications. Cholestanol deposition in tissues contributes to clinical manifestations, including neurological symptoms and tendon xanthomas. Dyslipidemia and abnormal cholesterol metabolism may also contribute to the increased risk of atherosclerosis and cardiovascular complications observed in some CTX patients.

Improved chemical synthesis, X-ray crystallographic analysis, and NMR characterization of (22R)-/(22S)-hydroxy epimers of bile acids

We report an improved synthesis of the (22R)- and (22S)-epimers of 3α,7α,12α,22-tetrahydroxy-5β-cholan-24-oic acid and 3α,7α,22-trihydroxy-5β-cholan-24-oic acid from cholic acid (CA) and chenodeoxycholic acid (CDCA), respectively. The principal reactions involved were as follows: (1) oxidative decarboxylation of the bile acid peracetates with lead tetraacetate, and (2) subsequent Reformatsky reaction of the 23,24-dinor-22-aldehydes with ethyl bromoacetate in the presence of activated Zn as a catalyst with the reaction temperature maintained precisely at 75 °C. The absolute configuration of the chiral center at C-22 of each epimer was established by single-crystal X-ray diffraction data using its ethyl ester-peracetate derivative. The (1)H- and (13)C-NMR spectra that permit the (22R)- and (22S)-epimers to be distinguished are reported as well as the specific (1)H shift effects induced by C(5)D(5)N. Bile acids having hydroxyl groups at C-22 are present in a variety of animal biles, previously have been difficult to identify, and are known to have distinctive physicochemical and biological properties.

Novel pathways of bile acid metabolism involving CYP3A4

The hepatic predominating cytochrome P450, CYP3A4, plays an essential role in the detoxification of bile acids and is important in pathological conditions such as cholestasis where CYP3A4 is adaptively up-regulated. However, the mechanism that triggers the up-regulation of CYP3A4 is still not clear. In this study, using recombinant CYP3A4 and human liver microsomes, we demonstrate that CYP3A4 can metabolise lithocholic acid into 3-dehydrolithocholic acid, a potent activator of the nuclear receptors, pregnane X receptor and 1,25-dihydroxy vitamin D3 receptor, which are known to regulate the expression of CYP3A4. This process thus provides a feed-forward metabolism of toxic bile acid that may be of importance in maintaining bile acid homeostasis. We also provide evidence for a novel CYP3A4-mediated metabolic pathway of the secondary bile acid deoxycholic acid. Patients treated with the antiepileptic drug carbamazepine, a CYP3A4 inducer, had markedly elevated urinary excretion of 1beta-hydroxydeoxycholic acid compared to healthy controls. The importance of CYP3A4 in this process was verified by incubations with recombinant CYP3A4 and human liver microsomes, both of which efficiently converted deoxycholic acid into 1beta-hydroxydeoxycholic acid. Interestingly, CYP3A4 was also found to be active against the secondary bile acid ursodeoxycholic acid.

Clinical and biochemical features, molecular diagnosis and long-term management of a case of cerebrotendinous xanthomatosis

Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive sterol storage disease characterised clinically by juvenile bilateral cataracts, progressive neurological dysfunction, and formation of tendon xanthomata. We describe the clinical and biochemical features, molecular diagnosis and long-term management of the first reported Australasian case of CTX. Molecular analysis confirmed the diagnosis of CTX and demonstrated that the patient was homozygous for a G-->A transition in the splice donor site of intron 4 of the sterol 27-hydroxylase gene. Serum cholestanol concentrations were decreased with the HMG-CoA reductase inhibitor simvastatin alone and greater reductions were achieved after the addition of the bile acid chenodeoxycholic acid; suggesting a synergistic effect of this combination. Despite serum cholestanol concentrations remaining within the low-normal range, there has been no significant improvement in mental and physical abilities or in EEG abnormalities with 5 years of treatment. Metabolism of radiolabeled 7-ketocholesterol to aqueous soluble products was absent in CTX-derived macrophages. Consistent with this finding, plasma 7 alpha-hydroxycholesterol, 7 beta-hydroxycholesterol, and 7-ketocholesterol concentrations were increased in the CTX subject compared with controls.

Gas chromatography of bile acids

Bile acids, the end products of cholesterol metabolism in the liver, are of vital importance in the tissue distribution of cholesterol. Abnormalities in cholesterol biosynthesis or metabolism are often reflected in the proportions, concentrations and conjugation of bile acids in various tissues and determination of bile acids in these tissues is important in the diagnosis of hepatobiliary diseases. Several methods for quantitative determination of bile acids in biological fluids are known and have been reviewed. In this review, we have discussed the gas-chromatographic method for determination of bile acids with special reference to bile acid quantitation in plasma, bile, urine and stool.

A two-year prospective study of the effect of ursodeoxycholic acid on urinary bile acid excretion and liver morphology in cystic fibrosis-associated liver disease

The efficacy of 2 years of treatment with ursodeoxycholic acid (UDCA) in cystic fibrosis (CF)-associated liver disease was evaluated by liver biopsies and liver function tests in 10 patients aged 8 to 28 years. The metabolism of UDCA was investigated by analysis of urinary bile acids with fast atom bombardment mass spectrometry (FABMS) and gas-liquid chromatography-mass spectrometry. Eight patients responded with normalization of liver function tests (LFT) and all with decreased serum levels of immunoglobulin G (IgG). Blind evaluation of liver biopsies indicated improved liver morphology with less inflammation and/or bile duct proliferation than before treatment with UDCA in 7 patients. Only 1 patient had signs of progression of clinical liver disease. The proportion of UDCA and isoUDCA in urine varied, but increased during treatment from a mean (median) of approximately 4% (3%) to 40% (40%) of total bile acids. The increase was not related to LFT. The secondary bile acids, such as lithocholic acid (LCA) and deoxycholic acid (DCA), did not increase significantly. The excretion pattern of glycosidic conjugates of UDCA and its metabolites was similar to that found in healthy individuals, UDCA and isoUDCA being mainly excreted in conjugation with N-acetylglucosamine. This study shows that UDCA modulates inflammation in CF-associated liver disease and indicates improvement of liver morphology during 2 years of treatment.

Effects of ursodeoxycholic acid on conjugated bile acids and progesterone metabolites in serum and urine of patients with intrahepatic cholestasis of pregnancy

BACKGROUND/AIMS AND METHODS

The mechanism(s) behind the effects of ursodeoxycholic acid on serum steroid sulphate profiles in patients with intrahepatic cholestasis of pregnancy is not clear. Conjugated progesterone metabolites and bile acids have therefore been analysed in serum and urine of patients with intrahepatic cholestasis of pregnancy before and during treatment with ursodeoxycholic acid using chromatographic and mass spectrometric methods.

RESULTS

The concentration of glycine-/taurine-conjugated bile acids decreased from 8.9+/-3 micromol/l (mean+/-SEM) before treatment to 1.8+/-0.6 micromol/l during treatment with ursodeoxycholic acid. The total bile acid excretion in urine decreased from 56+/-14 to 32+/-5.6 micromol/g creatinine. The proportion of cholic acid in serum and urine, and of 1beta-, 2beta- and 6alpha-hydroxylated cholic acids in urine decreased markedly during ursodeoxycholic acid while the percentages of 3alpha,12alpha-dihydroxy-3-oxo-4-cholenoic acid and chenodeoxycholic acid were unchanged. The levels in serum and excretion in urine of sulphated steroids decreased during ursodeoxycholic acid, by 45-49% for disulphates and 33-35% for monosulphates. The ratios of 3alpha- to 3beta-hydroxysteroid disulphates were lowered by ursodeoxycholic acid from 1.1 (mean) to 0.68 in serum, and from 1.2 to 0.70 in urine. The corresponding ratios for monosulphates before and during ursodeoxycholic acid were 6.9 and 4.5, respectively, in serum, and 21 and 5.2, respectively, in urine. The major monosulphates in urine, dominated by 5alpha-pregnane-3alpha, 20alpha-diol, were also conjugated with N-acetylglucosamine. The excretion of these double conjugates decreased from 27+/-8.4 to 15+/-5.3 micromol/g creatinine during ursodeoxycholic acid. In contrast to sulphated steroids, the concentrations of glucuronides were unchanged in serum and their excretion in urine tended to increase during ursodeoxycholic acid. The metabolism of ursodeoxycholic acid was similar to that described in nonpregnant subjects. In addition to metabolites hydroxylated in the 1beta-, 5beta-, 6alpha/beta and 22-positions, a 4-hydroxy-ursodeoxycholic acid was tentatively identified. This occurred predominantly as a double conjugate with glycine/taurine and glucuronic acid, as did other 4-hydroxylated bile acids of probable foetal origin.

CONCLUSIONS

The results are compatible with the contention that ursodeoxycholic acid stimulates the biliary excretion of sulphated progesterone metabolites, particularly those with a 3alpha-hydroxy-5alpha(H) configuration and disulphates. The effect(s) appears to be independent of the stimulation of bile acid secretion. An effect of ursodeoxycholic acid on the reductive metabolism of progesterone cannot be excluded.

Study of human isoursodeoxycholic acid metabolism

BACKGROUND/AIMS

The aim of this study was to examine the metabolism of isoursodeoxycholic acid (isoUDCA) in humans.

METHODS

IsoUDCA was synthesized of >99% purity and administered orally for 1 week, 3 x 250 mg/day, to six healthy male subjects. Bile acids were extracted from duodenal bile, serum, and 24-h urine samples collected before and at the end of the study period, separated into groups of conjugates, and analyzed by gas chromatography-mass spectrometry and fast atom bombardment mass spectrometry.

RESULTS

IsoUDCA was tolerated without any side effect. Liver function tests did not change. Bile acid concentrations (mean+/-SEM) increased from 11.9+/-1.87 to 15.3+/-1.37 mmol/l in bile (n.s.), and from 3.4+/-0.10 to 6.8+/-0.43 micromol/l in serum (p<0.05). Urinary excretion of bile acids increased from 5.3+/-0.29 to 82.2+/-7.84 micromol/24 h (p<0.01). All changes were due to significant increases of isoUDCA and UDCA in bile, serum and urine, and of 3-dehydro-UDCA, the 3-oxo intermediate of isomerization, in bile and in serum. The relative enrichments of isoUDCA, UDCA, and 3-dehydro-UDCA, were: in bile, 2.2%, 25.7%, and 0.7%; in serum, 24.7%, 23.5%, and 6.1%; and in urine, 83.7%, 2.0%, and 2.4%. Whereas 78% of serum isoUDCA was unconjugated, 93-94% of biliary and urinary isoUDCA was conjugated with N-acetylglucosamine.

CONCLUSIONS

This study indicates good tolerance and significant intestinal absorption of orally administered isoUDCA. IsoUDCA is extensively isomerized, probably both by intestinal and hepatic enzymes to yield UDCA which became the major biliary compound. In vitro, using the human hepatoblastoma cell line Hep G2, isoUDCA was found to be cytoprotective towards ethanol-induced cell injuries.

Delta 4-3-oxosteroid 5 beta-reductase deficiency: failure of ursodeoxycholic acid treatment and response to chenodeoxycholic acid plus cholic acid

BACKGROUND

In some infants with liver disease, 3-oxo-delta 4 bile acids are the major bile acids in urine, a phenomenon attributed to reduced activity of the delta 4-3-oxosteroid 5 beta-reductase required for synthesis of chenodeoxycholic acid and cholic acid. These patients form a heterogeneous group. Many have a known cause of hepatic dysfunction and plasma concentrations of chenodeoxycholic acid and cholic acid that are actually greater than those of the 3-oxo-delta 4 bile acids. It is unlikely that these patients have a primary genetic deficiency of the 5 beta-reductase enzyme.

AIMS

To document the bile acid profile, clinical phenotype, and response to treatment of an infant with cholestasis, increased plasma concentrations of 3-oxo-delta 4 bile acids, low plasma concentrations of chenodeoxycholic acid and cholic acid, and no other identifiable cause of liver disease.

PATIENTS

This infant was compared with normal infants and infants with cholestasis of known cause.

METHODS

Analysis of bile acids by liquid secondary ionisation mass spectrometry and gas chromatography-mass spectrometry.

RESULTS

The plasma bile acid profile of the patient was unique. She had chronic cholestatic liver disease associated with malabsorption of vitamins D and E and a normal gamma-glutamyltranspeptidase when the transaminases were increased. The liver disease failed to improve with ursodeoxycholic acid but responded to a combination of chenodeoxycholic acid and cholic acid.

CONCLUSION

Treatment of primary 5 beta-reductase deficiency requires the use of bile acids that inhibit cholesterol 7 alpha-hydroxylase.

The major metabolites of ursodeoxycholic acid in human urine are conjugated with N-acetylglucosamine

Ursodeoxycholic acid (750 mg/day) was administered orally to ten healthy subjects over a period of 10 days; 24 hr urine samples were collected the day before and on the last day of the study. Urinary bile acids were extracted, separated into groups of conjugates and analyzed by gas chromatography-mass spectrometry and fast atom bombardment mass spectrometry. Excretion of ursodeoxycholic acid rose from 70 to 2,915 micrograms/24 h. The highest increase was observed among N-acetylglucosamine conjugates, 90% of which constituted the previously unknown double conjugate of ursodeoxycholic acid with N-acetylglucosamine and glycine. Excretion of isoursodeoxycholic acid increased from 50 to 738 micrograms/24 h. This isomerization product of ursodeoxycholic acid was excreted almost exclusively as N-acetylglucosamine conjugate. In total, N-acetylglucosamine conjugates constituted 50% of urinary metabolites of ursodeoxycholic acid. In addition, metabolites of ursodeoxycholic acid hydroxylated at carbon atoms 1, 6, 22 and possibly 21 were observed. These compounds were also found as conjugates with N-acetylglucosamine. Their formation from ursodeoxycholic acid was definitely demonstrated by 13C-labeling after giving [24-13C]ursodeoxycholic acid to one of the healthy subjects and to a patient with extrahepatic cholestasis in whom hydroxylation of ursodeoxycholic acid at C-23 was also observed. The patient was also found to excrete the double conjugate of ursodeoxycholic acid with N-acetylglucosamine and taurine. The N-acetylglucosaminidation of ursodeoxycholic acid in vivo was shown to occur at C-7.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of ursodeoxycholic acid on liver and bile duct disease in primary sclerosing cholangitis. A 3-year pilot study with a placebo-controlled study period

Primary sclerosing cholangitis is a cholestatic disease of the liver characterized by progressive fibrotic inflammation and obliteration of the extra- and/or intrahepatic bile ducts. There is no effective therapy. We, therefore, studied the safety and efficacy of ursodeoxycholic acid in patients with primary sclerosing cholangitis with or without additional ulcerative colitis. In a 1-year ursodeoxycholic acid treatment period, which preceded the controlled study period, ursodeoxycholic acid was well tolerated in 22 of 24 patients with ulcerative colitis and in all three patients without ulcerative colitis. In two patients with ulcerative colitis the dose of 750 mg ursodeoxycholic acid/day led to diarrhea, but following reduction of the dose to 500 and 250 mg/day ursodeoxycholic acid was well tolerated. After 1 year of ursodeoxycholic acid treatment, 20 patients were randomly assigned to receive either ursodeoxycholic acid 750 mg/day or placebo. All of them finished a double-blind, placebo-controlled study period. During ursodeoxycholic acid treatment, the liver enzymes improved markedly. The difference in alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and gamma-glutamyltransferase between the placebo and ursodeoxycholic acid group was significant (p < 0.05). Following ursodeoxycholic acid treatment, pruritus and fatigue improved in half of the patients but the difference between the placebo and ursodeoxycholic acid group was not significant. According to the ethical guidelines, after 3 months of placebo treatment, the controlled study had to be discontinued because of a more than twofold increase of serum transaminases in 8/10 patients on placebo. After the end of the controlled study, all patients were continuously treated with ursodeoxycholic acid for up to 4 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Biotransformation of orally administered ursodeoxycholic acid in man as observed in gallbladder bile, serum and urine

The aim of this study was to evaluate the biotransformation of orally administered ursodeoxycholic acid in man. The distribution of ursodeoxycholic acid and its metabolites in gallbladder bile, in serum and in urine with emphasis on separation of their unconjugated, amidated and sulfated species in particular, was investigated. Seven gallstone patients were given 750 mg of ursodeoxycholic acid daily for 2-3 weeks. Six gallstone patients who did not receive ursodeoxycholic acid served as controls. Ursodeoxycholic acid became the major bile acid in gallbladder bile contributing 43% to total bile acids. 2% of biliary ursodeoxycholic acids were in the unconjugated form, 87% in the amidated form and 11% in the sulfated form. Iso-ursodeoxycholic acid was found in bile in small amounts and was present only as the sulfated species and not as the amidated one. Other metabolites of ursodeoxycholic acid tentatively identified in bile were 1 beta, 12 beta, 6 alpha- and 21,22-hydroxylated derivatives of ursodeoxycholic acid. Lithocholic acid in bile tended to increase under ursodeoxycholic acid treatment and was positively correlated to ursodeoxycholic acid. The concentration of cholic acid in bile decreased significantly whereas the levels of deoxycholic acid and chenodeoxycholic acid did not change. Total bile acid concentration in serum and excretion of bile acids in urine increased from 5.4 +/- 1.1 to 18.4 +/- 9.5 mumol l-1 (mean +/- SD, P < 0.005) and from 5.6 +/- 1.3 to 13.1 +/- 7.9 mumol g-1 creatinine (mean +/- SD, P < 0.05) after ursodeoxycholic acid ingestion mainly due to spillover and excretion of ursodeoxycholic acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Bile acid N-acetylglucosaminidation. In vivo and in vitro evidence for a selective conjugation reaction of 7 beta-hydroxylated bile acids in humans

The aim of this study was to define whether N-acetylglucosaminidation is a selective conjugation pathway of structurally related bile acids in humans. The following bile acids released enzymatically from N-acetylglucosaminides were identified: 3 alpha,7 beta-dihydroxy-5 beta-cholanoic (ursodeoxycholic), 3 beta, 7 beta-dihydroxy-5 beta-cholanoic (isoursodeoxycholic), 3 beta,7 beta-dihydroxy-5 alpha-cholanoic (alloisoursodeoxycholic), 3 beta,7 beta-dihydroxy-5-cholenoic, 3 alpha,7 beta,12 alpha-trihydroxy-5 beta-cholanoic, and 3 alpha,6 alpha,7 beta-trihydroxy-5 beta-cholanoic acids. The selectivity of conjugation was studied by administration of 0.5 g ursodeoxycholic (UDCA) or hyodeoxycholic (HDCA) acids, labeled with 13C, to patients with extrahepatic cholestasis, and of 0.5 g of 13C-labeled chenodeoxycholic acid (CDCA) to patients with extra- or intrahepatic cholestasis. After administration of [24-13C]-CDCA, labeled glucosides, and the glucuronide of CDCA were excreted in similar amounts. Labeled N-acetylglucosaminides of UDCA and isoUDCA were also formed. When [24-13C]-UDCA was given, 13C-label was detected in the N-acetylglucosaminide, the glucosides, and the glucuronide of UDCA, and in the N-acetylglucosaminide of isoUDCA. In the patient studied, 32% of the total UDCA excreted in urine was conjugated with N-acetylglucosamine. In contrast, 96% of the excreted amount of [24-13C]HDCA was glucuronidated, and 13C-labeled glucosides but no N-acetylglucosaminide were detected. The selectivity of N-acetylglucosaminidation towards bile acids containing a 7 beta-hydroxyl group was confirmed in vitro using human liver and kidney microsomes and uridine diphosphate glucose (UDP)-N-acetylglucosamine. These studies show that N-acetylglucosaminidation is a selective conjugation pathway for 7 beta-hydroxylated bile acids.

Formation of iso-ursodeoxycholic acid during administration of ursodeoxycholic acid in man

The appearance of iso-ursodeoxycholic acid (isoUDCA; 3 beta,7 beta-dihydroxy-5 beta-cholan-24-oic acid) in serum of patients with chronic cholestatic liver disease and of healthy subjects during administration of ursodeoxycholic acid (UDCA) is reported. Comparison of the mass spectrum of the newly appearing bile acid with that of authentic 3 beta,7 beta-dihydroxy-5 beta-cholan-24-oic acid revealed its identity as the 3 beta-epimer of UDCA. The appearance of 13C-isoUDCA in serum after ingestion of 13C-UDCA proved its product precursor relationship with UDCA. The putative intermediate in the epimerization of UDCA to isoUDCA, 3-oxo-7 beta-hydroxy-5 beta-cholan-24-oic acid, was identified in serum of patients with cholestatic liver disease during treatment with UDCA. Serum concentrations of isoUDCA after 4 weeks of UDCA treatment were 1.37 +/- 0.79 mumol/l (mean +/- S.D.) in eight patients with primary biliary cirrhosis (PBC), 1.25 +/- 0.91 mumol/l in six patients with primary sclerosing cholangitis (PSC) and 3.87 +/- 0.44 mumol/l in four healthy controls. The intestinal bacterial flora as well as microsomal enzymes of the liver may be involved in the epimerization of UDCA to isoUDCA as indicated by decreased serum levels of isoUDCA under antibiotic treatment with doxycycline (100 mg/day) in healthy subjects and a correlation (r = 0.873, p less than 0.001) between the hepatic microsomal function measured by the 14C-aminopyrine breath test and the fractional conversion of applied UDCA to isoUDCA (isoUDCA/UDCA + isoUDCA) in patients with PBC or PSC. Future studies of bile acid metabolism under UDCA treatment should include measurement of isoUDCA to further elucidate its biological role.

Ursodeoxycholic acid-induced changes of plasma and urinary bile acids in patients with primary biliary cirrhosis

Ursodeoxycholic acid treatment of patients with primary biliary cirrhosis may lead to relief of pruritus and improvement of biochemical liver tests. The changes in serum and urinary bile acids induced by ursodeoxycholic acid treatment were studied. After 29 patients with primary biliary cirrhosis were treated with ursodeoxycholic acid (750 to 1,000 mg/day) for 6 to 12 mo because of an increase in ursodeoxycholic acid, total plasma bile acids increased from 30.5 +/- 6 mumol/L (mean +/- S.E.M.) to 52.7 +/- 11.7 mumol/L (p less than 0.01). The increase in total plasma bile acids correlated significantly with concentrations of plasma bile acid before treatment (p less than 0.01). The concentrations of endogenous bile acids decreased, mainly because of a decrease of cholic acid. During treatment, glycine conjugation increased and taurine conjugation decreased, whereas sulfation and glucuronidation of bile acids were unchanged. In 10 patients with primary biliary cirrhosis in stages III and IV, urinary excretion of bile acids was also studied. After treatment, ursodeoxycholic acid and its 3-beta isomer and C-1-hydroxylated and C-6-hydroxylated derivatives were also excreted. During treatment, urinary excretion of endogenous bile acids decreased. The increase of ursodeoxycholic acid and the decrease of endogenous bile acids may both be related to the improvement of biochemical liver tests in precirrhotic stages of the disease. In cirrhosis, endogenous bile acids in plasma remained high and changes in liver tests were small.

Capillary gas chromatography/negative ion chemical ionization mass spectrometry for the quantification of bile acids including 1 beta-hydroxylated and unsaturated bile acids in serum and urine

12 bile acids, including 1 beta-hydroxylated and unsaturated bile acids, have been quantified by capillary gas chromatography/negative ion chemical ionization mass spectrometry, using the trimethylsilyl(TMS) ether derivatives of bile acid pentafluorobenzyl(PFB) esters. The analysis time is 12 min and the minimum measurable amount is 100 fg for each bile acid. Bile acids in 200 microL of serum and 50 microL of urine from healthy human adults were measured. These small sample sizes enhance the practicality of using this method as a screening test for bile acids in the serum and urine of human infants, where small sample size is a major problem.

Effect of ursodeoxycholic acid on bile acid metabolism in primary biliary cirrhosis

We have compared the effect of ursodeoxycholic acid with placebo on the clinical state, blood liver chemistries and serum and urinary bile acids in four patients with primary biliary cirrhosis. All parameters were evaluated monthly, and bile acid composition was measured by capillary gas-liquid chromatography. At the time of admission, all patients showed intense pruritus, and their serum alkaline phosphatase, AST and ALT levels were elevated 4.3, 2.7 and 2.3 times over control values. Serum bile acids were elevated almost 38-fold with 2.5 times more cholic acid than chenodeoxycholic acid. Urinary bile acid output was elevated 28 times the control values, and 36% were 1 beta-hydroxycholic acid, 1 beta-hydroxydeoxycholic acid and hyocholic acid (3 alpha,6 alpha, 7 alpha-trihydroxy-5 beta-cholanoic acid). Three months of placebo administration did not significantly affect the clinical or biochemical presentations, and the serum and urinary bile acid composition did not change. In contrast, ursodeoxycholic acid feeding (12 to 15 mg per kg per day) for 6 months abolished pruritus in two and lessened itching in two subjects and reduced serum alkaline phosphatase, AST and ALT levels by 21, 35 and 47%, respectively. The mean values for the total serum bile acid concentrations in these patients declined 26% from the pretreatment value, but the proportion of ursodeoxycholic acid increased from 3 to 40% of the total bile acids; thus, total fasting serum endogenous bile acid levels decreased almost 50%. Similar changes were noted in the urinary bile acids, in which ursodeoxycholic acid became the major bile acid, and approximately 18% were hydroxylated at C-1, C-6 and C-21.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebrotendinous xanthomatosis: a review of biochemical findings of the patient population in The Netherlands

This study gives a review of the results obtained from biochemical investigations of 20 patients in The Netherlands suffering from cerebrotendinous xanthomatosis, an inborn error of metabolism in bile acid synthesis. Diagnosis can best be established by determining the excretion of urinary bile alcohols, in particular 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha,23,25-pentol, in urine by means of capillary gas chromatography. Measurement of serum cholestanol levels or serum cholestanol/cholesterol ratios, commonly used for establishing cerebrotendinous xanthomatosis, are not reliable. The effectiveness of the different therapies, i.e. administration of bile acids, can be evaluated by monitoring the urinary excretion of bile alcohols. From such investigations it was concluded that cholic acid especially, but also chenodeoxycholic acid are the therapies of choice for the treatment of cerebrotendinous xanthomatosis. All patients, until now diagnosed in The Netherlands were not discovered before the third or fourth decade of life because the characteristic signs only then become manifest clearly. Unfortunately, because sterol storage is almost irreversible, therapy only results in minor improvements of the patient's condition. Therefore early detection of the presence of cerebrotendinous xanthomatosis is desirable so that treatment can start before extensive storage of sterols is a fact. We developed some laboratory assays with the purpose of early detection. One consists of the detection of cerebrotendinous xanthomatosis carriers by subjecting them to oral cholestyramine administration and monitoring the urinary excretion of the bile alcohol 5 beta-cholestane-3 alpha,7 alpha,12 alpha,23,25-pentol before and after treatment. Secondly, a relatively simple screening test for cerebrotendinous xanthomatosis was developed based on an enzymatic assay of 7 alpha-hydroxylated steroids in urine. After suitable modification this assay in principle allows the screening of large populations for the existence of cerebrotendinous xanthomatosis and thus to detect the disease at an earlier stage of life.